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REVISTA CONSTRUCŢIA DE MAŞINI - SERIE NOUĂ

Anul 63, Nr. 1 / 2011

Din sumar

TEHNOLOGIE INOVATIVĂ / INNOVATIVE TECHNOLOGY MODELARE ŞI SIMULARE / MODELLING AND SIMULATION ECONOMIE INDUSTRIALĂ. ECONOMIA CUNOAŞTERII /

INDUSTRIAL ECONOMY. KNOWLEDGE ECONOMY

DEZVOLTARE DURABILĂ /

SUSTAINABLE DEVELOPMENT

ISSN 0573 – 7419 EDITOR: ICTCM – CITAf 041303 Bucuresti Şos. Olteniţei nr. 103, sector 4, O.P. 8 Tel: 021 332.37.70/234 Fax: 021 332.07.75 / 021 332.31.95 E-mail: [email protected]

Responsabil editor: Irina Rădulescu Responsabil difuzare: Ionuţ Dimache INFORMAŢII, ABONAMENTE: Revista este evaluată CNCSIS la categoria B+, apare trimestrial. Abonamentele se fac direct, prin dispoziţie de plată sau mandat poştal, trimis pe adresa revistei. CONT – ICTCM: nr. RO58 RNCB 0075 0352 1240 0001; BCR sector 4 TIPAR: ICTCM – CITAf COPYRIGHT 2003 Toate drepturile asupra acestei ediţii sunt rezervate ICTCM – CITAf. Nu este permisă reproducerea integrală sau parţială a articolelor din revista „Tehnologia Inovativă” fără consimţământul scris al editorului. Opiniile exprimate în revistă aparţin semnatarilor articolelor, fără să reflecte obligatoriu şi punctul de vedere al editorului.

TEHNOLOGIA INOVATIVĂ – Revista „Construcţia de maşini” nr. 1 / 2011

ANUL 63 / 2011 – NR. 1

TEHNOLOGIA INOVATIVĂ

REVISTA CONSTRUCŢIA DE MAŞINI

COLEGIUL DE REDACŢIE Octavian BOLOGA - Universitatea „Lucian Blaga” din Sibiu

Olivier BONNEAU – Universitatea din Poitiers, Franţa

Ion BOSTAN – Universitatea Tehnică a Moldovei

K.D. BOUZAKIS – Aristoteles University of Thessaloniki, Grecia

Doug BRANHAM - Lubrication Systems Company, Houston, Texas, USA

Dan BRÎNDAŞU - Universitatea „Lucian Blaga” din Sibiu

Mircea CIOBANU - Universitatea „Ştefan cel Mare” din Suceava

Valeriu DULGHERU – Universitatea Tehnică a Moldovei

Dan FILIPOIU - Universitatea POLITEHNICA din Bucureşti

Michel FILLON – Universitatea din Poitiers, Franţa

Mohamed HAJJAM – Universitatea din Poitiers, Franţa

Tudor ICLĂNZAN - Universitatea „Politehnica” din Timişoara

Nicolae Valentin IVAN - Universitatea „TRANSILVANIA” din Braşov

Gheorghe MOGAN – Universitatea „TRANSILVANIA” din Braşov

Ilie MUSCĂ - Universitatea „Ştefan cel Mare” din Suceava

Nicolae OANCEA - Universitatea „Dunărea de Jos” din Galaţi

Dumitru OLARU - Universitatea Tehnică „Gheorghe Asachi” din Iaşi

Juozas PADGURSKAS – Lithuanian University of Agriculture, Lithuania

Radu POPESCU – Academia Română - INCE – CEIS, Bucureşti

Tudor PRISĂCARU - Universitatea POLITEHNICA din Bucureşti

Vasile PUIU - Universitatea din Bacău

Stanisław PYTKO - University of Science and Technology, Kraków, Poland

Alexandru RĂDULESCU - Universitatea POLITEHNICA din Bucureşti

Minodora RÎPĂ - Universitatea „Dunărea de Jos” din Galaţi

Lucian TUDOSE - Universitatea din Cluj

Thami ZEGHLOUL – Universitatea din Poitiers, Franţa


COMITET ONORIFIC

Gheorghe AMZA - Universitatea POLITEHNICA din Bucureşti

Niculae Napoleon ANTONESCU – Universitatea „Petrol şi Gaze” din Ploieşti

Traian AURITE - Universitatea POLITEHNICA din Bucureşti

Gavrilă CALEFARIU - Universitatea „TRANSILVANIA” din Braşov

Mircea COZMÎNCĂ - Universitatea Tehnică „Gheorghe Asachi” din Iaşi

Emanuel DIACONESCU – Universitatea „Ştefan cel Mare” din Suceava

Marian GHEORGHE - Universitatea POLITEHNICA din Bucureşti

Constantin ISPAS - Universitatea POLITEHNICA din Bucureşti

Valeriu JINESCU - Universitatea POLITEHNICA din Bucureşti

Aurel JULA - Universitatea „TRANSILVANIA” din Braşov

Constantin MINCIU - Universitatea POLITEHNICA din Bucureşti

Eugen PAY - Universitatea de Nord din Baia Mare

Iulian POPESCU - Universitatea din Craiova

Aurelian VLASE - Universitatea POLITEHNICA din Bucureşti

Ioan VOICA - Universitatea POLITEHNICA din Bucureşti

EDITOR

Oficiul de Informare Documentară pentru Industrie, Cercetare, Management din cadrul

Centrului Incubator Tehnologic de Afaceri S.C. ICTCM S.A. BUCUREŞTI

RESPONSABIL EDITOR

Irina Rădulescu

REDACTOR Irina Rădulescu

WEBMASTER Ramona Ioanid


CUPRINS

TEHNOLOGIE INOVATIVĂ / INNOVATIVE TECHNOLOGY

1. ABRASIVE FINISHING IN MAGNETIC FIELD – AN EFFICIENT METHOD OF PROCESSING. PART I: PHYSICAL MODELS AND TYPES OF PROCESSING pag. 11 Mircea Ciobanu1, Marius Băeşu2 Universitatea ”Ştefan cel Mare”, Suceava, ROMANIA

2. ABRASIVE FINISHING IN MAGNETIC FIELD (A.F.M.F.) – AN EFFICIENT METHOD OF PROCESSING. PART II: MATERIALS USED IN A.F.M.F. pag. 17 Marius Băeşu1, Mircea Ciobanu2 Universitatea ”Ştefan cel Mare”, Suceava, ROMANIA

3. 3D ABRASIVE WATERJET CUTTING AND MECHANICAL

MACHINING EQUIPMENT pag. 21 Cristian Birtu1, Valeriu Avramescu1, Roxana Grejdănescu1 S.C. ICTCM S.A. Bucharest, ROMANIA

4. METHODOLOGY OF MONITORING THE LOADINGS ON THE JAW CHUCK FOR DRILLING AND MILLING PROCESSING pag. 25 Raluca Magdalena Nita1, Adrian Ghionea2, Florin Sabou3 1 S.C. ICTCM S.A. - Mechanical Engineering and Research Institute, Faculty Engineering and Technological System Management, University POLITEHNICA of Bucharest, ROMANIA, 2 Prof. PHD Eng., Engineering and Technological System Management, University POLITEHNICA of Bucharest, ROMANIA 3 Universität Stuttgart, Institut für Werkzeugmaschinen, GERMANY

5. TEHNOLOGIE PENTRU SORTAREA ŞI MĂRUNŢIREA DEŞEURILOR POLIMERICE COMPOZITE. REALIZAREA UNEI FRACŢII DE RECICLAT DE ÎNALTĂ CALITATE, DESTINATĂ REUTILIZĂRII ÎN PROCESUL DE FABRICAŢIE (TECHNOLOGY FOR SORTING AND CRUMBLING OF THE POLYMERIC COMPOSITE WASTE. THE ACHIEVEMENT OF A HIGH-QUALITY RECYCLED FRACTION FOR THE REUSE IN MANUFACTURING PROCESS) pag. 33 Avramescu Valeriu1, Paun Loredana Theodora1, Teodorescu Florin1, Dumitru Condurache1, Rosu Dorin2, Nita Raluca Magdalena1, Teodorescu Horatiu3 1Mechanical Engineering and Research Institute, Bucharest, ROMANIA, 2Compozite Ltd, Braşov, ROMANIA, 3Transilvania University, Braşov, ROMANIA MODELARE ŞI SIMULARE / MODELLING AND SIMULATION

6. TENSILE TEST OF A COMPOSITE MATERIAL USED IN BULIDING OF A MULTIFUNCTIONAL MACHINE TOOL STRUCTURE pag. 39 Loredana Păun1, Valeriu Avramescu1, Horaţiu Teodorescu2 1 Mechanical Engineering and Research Institute, Bucharest, ROMANIA, 1 Mechanical Engineering and Research Institute, Bucharest, ROMANIA, 2 Transilvania University, Brasov, ROMANIA

7. AN APROXIMATIVE DEFORMATION ANALYSIS WITH FINITE ELEMENT METHOD FOR A DRILLING BAR pag. 43 Iuliana Iancu Universitatea POLITEHNICA Bucureşti, ROMANIA


ECONOMIE INDUSTRIALĂ. ECONOMIA CUNOAŞTERII / INDUSTRIAL ECONOMY. KNOWLEDGE ECONOMY

8. ISSUES CONCERNING THE SMEs ECONOMIC EVOLUTION AND SOCIAL RELATIONS

EXPLORED THROUGH COLLABORATIVE WORKING ENVIRONMENT pag. 49

Piţurescu Ioan1, Marian Aurel2, Rădulescu Irina3, Onu Ana Maria4, Rotaru Constantin5, Dobrea Cătălin6 1 S.C. ICTCM S.A. Bucharest, ROMANIA, e-mail:[email protected], 2 S.C. AMCAT S.R.L Bucharest, ROMANIA, e-mail: [email protected], 3 S.C. ICTCM S.A. Bucharest, ROMANIA, e-mail:[email protected], 4 INIMM Bucharest, ROMANIA, e-mail: [email protected], 5 INIMM Bucharest, ROMANIA, e-mail: [email protected], 6ASE Bucharest, ROMANIA, e-mail: [email protected] DEZVOLTARE DURABILĂ / SUSTAINABLE DEVELOPMENT

9. CONSIDERAŢII PRIVIND UTILIZAREA RESURSELOR ENERGETICE REGENERABILE.

STUDIU DE CAZ: SECTORUL ENERGETIC DIN ROMÂNIA (CONSIDERATIONS ON THE USE OF RENEWABLE ENERGY RESOURCES. CASE STUDY: THE ROMANIAN ENERGY SECTOR) pag. 55 Gheorghe Mihaela1, Rădulescu Alexandru Valentin2, Rădulescu Irina3 1Universitatea POLITEHNICA Bucureşti, Bucureşti , ROMANIA, e-mail: [email protected], 2Universitatea POLITEHNICA Bucureşti, Bucureşti , ROMANIA, e-mail: [email protected], 3 S.C. ICTCM S.A. Bucureşti, Bucureşti , ROMANIA, e-mail: [email protected]


ABSTRACTS “INNOVATIVE TECHNOLOGY” 1 / 2011

ABRASIVE FINISHING IN MAGNETIC FIELD – AN EFFICIENT METHOD OF PROCESSING.

PART I: PHYSICAL MODELS AND TYPES OF PROCESSING

Mircea Ciobanu1, Marius Băeşu2

1 Universitatea ”Ştefan cel Mare”, Suceava, ROMANIA, [email protected] 2 Universitatea ”Ştefan cel Mare”, Suceava, ROMANIA, [email protected]

The paper presents aspects concerning the use of magnetic field in finishing surfaces in manufacturing technologies. Abrasive finishing in magnetic field is defined as a process by which material is removed, such as in surface finishing and deburring, with the presence of a magnetic field in the machining zone (Baron, 1986). Fundamental research in this area have been done in USA , Russia, Japan, Ukraine, Belarus, England, Hungary, Germany, Bulgaria, Romania, India, China etc. In this process, the finishing pressure required to execute the microcutting is made with the help of a magnetic field. The authors aim to present a set of works that highlight this finishing process, which can be completed with the findings concerning its implementation in industry. ABRASIVE FINISHING IN MAGNETIC FIELD

(A.F.M.F.) – AN EFFICIENT METHOD OF PROCESSING.

PART II: MATERIALS USED IN A.F.M.F.

Marius Băeşu1, Mircea Ciobanu2 1 Universitatea ”Ştefan cel Mare”, Suceava, ROMANIA, [email protected] 2 Universitatea ”Ştefan cel Mare”, Suceava, ROMANIA, [email protected]

This paper summarizes the materials used in the abrasive finishing in magnetic field (AFMF). Thus, there are highlighted types of materials used in each of the AFMF finishing variants. The evolution of materials used in AFMF is continuous, meaning that there are new compositions of such materials. The main disadvantage is their cost and relatively difficult to obtain technology.

3D ABRASIVE WATERJET CUTTING AND MECHANICAL MACHINING EQUIPMENT

Cristian Birtu1, Valeriu Avramescu1, Roxana Grejdănescu1

1 S.C. ICTCM S.A. Bucharest, ROMANIA, e-mail: [email protected], [email protected],[email protected]

The paper presents a project achievement, which has as a main goal the development and the usage implementation of a complex/module equipment, which is dedicated to the conventional and nonconventional processing operations, on the same machine, for the current production of the beneficiary and also for the preparation for the ones which will be assimilated. Researches are based on the achievement of 3D abrasive waterjet cutting and mechanical machining equipment, which is designed to manufacture of materials using two technologies on the same equipment: waterjet cutting and mechanical machining (drilling).

METHODOLOGY OF MONITORING

THE LOADINGS ON THE JAW CHUCK FOR DRILLING AND MILLING PROCESSING Raluca Magdalena Nita1, Adrian Ghionea2, Florin Sabou3

1 S.C. ICTCM S.A. - Mechanical Engineering and Research Institute, Faculty Engineering and Technological System Management, University POLITEHNICA of Bucharest, ROMANIA, PDH student, e-mail: ralu_magda.yahoo.com 2 Prof. PHD Eng., Engineering and Technological System Management, University POLITEHNICA of Bucharest, ROMANIA 3 Universität Stuttgart, Institut für Werkzeugmaschinen, GERMANY

In this paper are presented the stages of preparing the technological system machine-tool-device-tool-work-piece assembly in order to implement a data acquisition system for recording the cutting forces on the principal orthogonal directions Fx, Fy, Fz and the cutting momentum Mz, during drilling, enlarging and lateral milling. During experimental researches were used three work-pieces from different materials: aluminum, ST52 and 42MoCrV. The paper also presents a methodology of monitoring for a jaw fixing device, for its integration in an advanced production system.


TEHNOLOGIE PENTRU SORTAREA SI MARUNTIREA DESEURILOR POLIMERICE COMPOZITE. REALIZAREA UNEI FRACTII

DE RECICLAT DE INALTA CALITATE, DESTINATA REUTILIZARII IN PROCESUL

DE FABRICATIE

(TECHNOLOGY FOR SORTING AND CRUMBLING OF THE POLYMERIC

COMPOSITE WASTE. THE ACHIEVEMENT OF A HIGH-QUALITY RECYCLED

FRACTION FOR THE REUSE IN MANUFACTURING PROCESS)

Avramescu Valeriu1, Paun Loredana Theodora1, Teodorescu Florin1, Dumitru Condurache1, Rosu Dorin2, Nita Raluca Magdalena1, Teodorescu Horatiu3

1Mechanical Engineering and Research Institute, Bucharest, ROMANIA, [email protected], 2Compozite Ltd, Brasov, ROMANIA, [email protected] 3Transilvania University, Brasov, ROMANIA, [email protected]

This paper presents a technology for sorting and crumbling of waste polymer composites and achieving a high quality recycled fractions by mechanical recovery of glass and/or carbon, for their reuse in the manufacturing of composite structures. The technical problem is solved by the technology of glass mechanical recovery and/or shredding carbon structures with composite materials and sorting them by means of special equipment for peeling, defibrillation and recovery.

TENSILE TEST OF A COMPOSITE MATERIAL USED IN BULIDING

OF A MULTIFUNCTIONAL MACHINE TOOL STRUCTURE

Loredana Păun1, Valeriu Avramescu1, Horaţiu Teodorescu2 1 Mechanical Engineering and Research Institute, Bucharest, ROMANIA, [email protected] 1 Mechanical Engineering and Research Institute, Bucharest, ROMANIA, [email protected] 2 Transilvania University, Brasov, ROMANIA, [email protected]

The paper presents an experimental analysies in order to find the tensile characteristic of a pulltruded composite material which is used in building of a CNC multifunctional machine tool structure, in order to get a low weight of the machine. The tensile test was accomplished on two directions becouse of the matreial anizotropy: along and perpendicular to fibre direction.The tensile test

shows that the mechanical properties along the fibre direction are much higher than the transverse to the fiber direction, which shows a strong anisotropy of the composite material.

AN APROXIMATIVE DEFORMATION ANALYSIS WITH FINITE ELEMENT

METHOD FOR A DRILLING BAR

Iuliana Iancu Universitatea POLITEHNICA Bucureşti, ROMANIA, [email protected] This paper is propose to analize the stability of a drilling bar, used finite element method.In the cutting process,behind the workpiece actions many forces and moments, which determine the instability in and after the process.In the technical system are the: cutting force, drilling moment,elastic forces of the system stifness of the system,damping forces of the system, fixture forces.Element finite method is based by discretization of the body and in mechanical method a body are the mixt of the many parts.

ISSUES CONCERNING THE SMEs

ECONOMIC EVOLUTION AND SOCIAL RELATIONS

EXPLORED THROUGH COLLABORATIVE WORKING

ENVIRONMENT Piţurescu Ioan1, Marian Aurel2, Rădulescu Irina3, Onu Ana Maria4, Rotaru Constantin5, Dobrea Cătălin6 1 S.C. ICTCM S.A. Bucharest, ROMANIA, e-mail:[email protected], 2 S.C. AMCAT S.R.L Bucharest, ROMANIA, e-mail: [email protected], 3 S.C. ICTCM S.A. Bucharest, ROMANIA, e-mail:[email protected], 4 INIMM Bucharest, ROMANIA, e-mail: [email protected], 5 INIMM Bucharest, ROMANIA, e-mail: [email protected], 6ASE Bucharest, ROMANIA, e-mail: [email protected] The paper analyzes the Romanian SMEs situation and it shows their economical development and social relation, also the problems appeared during their activity. Because they don’t have mechanisms and information capacity regarding key aspects of economic life, it has developed an useful tool for SMEs. Thus it is proposed an Integrated Platform for SMEs. It will ensure the interest vestors coupling for the economic agents, on various information categories related to the technological and organizational specifics, connected to the offers, aided by the Collaborative Work Environment.


CONSIDERAŢII PRIVIND UTILIZAREA RESURSELOR ENERGETICE

REGENERABILE. STUDIU DE CAZ: SECTORUL ENERGETIC

DIN ROMÂNIA

(CONSIDERATIONS ON THE USE OF RENEWABLE ENERGY RESOURCES.

CASE STUDY: THE ROMANIAN ENERGY SECTOR)

Gheorghe Mihaela1, Rădulescu Alexandru Valentin2, Rădulescu Irina3 1Universitatea POLITEHNICA Bucureşti, Bucureşti , ROMANIA, e-mail: [email protected], 2Universitatea POLITEHNICA Bucureşti, Bucureşti , ROMANIA, e-mail: [email protected], 3 S.C. ICTCM S.A. Bucureşti, Bucureşti , ROMANIA, e-mail: [email protected]

The paper describes the aims and main strands of EU policy on renewable energy resources use, the measures taken to conserve energy and reduce CO2 emissions, as well as priority projects and directions of development of the Romanian energy sector, in this context.


11

ABRASIVE FINISHING IN MAGNETIC FIELD – AN EFFICIENT METHOD OF PROCESSING.

PART I: PHYSICAL MODELS AND TYPES OF PROCESSING

Mircea Ciobanu1, Marius Băeşu2


REZUMAT Lucrarea prezintă aspecte privind utilizarea câmpului magnetic la finisarea suprafeţelor în construcţia de maşini. Un proces magnetic abraziv este definit ca un proces (finisare, debavurare), prin care materialul este îndepărtat în prezenţa unui câmp magnetic în zona de prelucrare (Baron, 1986). Cercetări fundamentale în domeniu au fost efectuate în Statele Unite ale Americii, Rusia, Japonia, Ucraina, Belarus, Anglia, Ungaria, Germania, Bulgaria, România, India, China etc. În cadrul acesui procedeu, presiunea de finisare necesară grăunţilor pentru a realize microaşchierea, este generată cu ajutorul unui câmp magnetic. Autorii îşi propun să prezinte un set de lucrări care să evidenţieze acest procedeu de finisare, care poate fi completat cu concluziile privind punerea sa în aplicare în industrie. ABSTRACT The paper presents aspects concerning the use of magnetic field in finishing surfaces in manufacturing technologies. Abrasive finishing in magnetic field is defined as a process by which material is removed, such as in surface finishing and deburring, with the presence of a magnetic field in the machining zone (Baron, 1986). Fundamental research in this area have been done in USA , Russia, Japan, Ukraine, Belarus, England, Hungary, Germany, Bulgaria, Romania, India, China etc. In this process, the finishing pressure required to execute the microcutting is made with the help of a magnetic field. The authors aim to present a set of works that highlight this finishing process, which can be completed with the findings concerning its implementation in industry. KEYWORDS: finishing, abrasive, magnetic abrasive finishing. CUVINTE CHEIE: finisare, abraziv, finisare magneto-abrazivă.

1. INTRODUCTION

In recent years there has been a considerable increase in use of magnetic technique for many purposes in the metalworking field. Magnetic forces provides elegant solutions to many problems that can resolved but clumsily by purely mechanical means. Magnetic methods are commonly used for work holding: the convenient location of instruments and tools and their component parts ; the separation and handling of steel sheets ; the clarifying of coolant and many others purposes.

They also find application in the inspection of

materials and finishing work and are now being used for forming metal and such unusual purpose as the provision of virtually frictionless bearings in highly specialized equipment.

The four popular types of magnetic abrasive process are: Magnetic Abrasive Finishing (MAF); Magnetic Fluid Grinding (MFG) also called Magnetorheological Finishing (MRF), Magnetic Abrasive Jet Machining (MAJ) and Magnetorheological Abrasive Flow Finishing (MRAFF) [13].


12

1. Magnetic Abrasive Finishing is based on the magnetic field capacity of rising and carrying small grained particles that should have abrasive and magnetic properties. Between the poles of the magnetic system and the piece to be finished it occurs a "magnetic abrasive brush", characterized by the orientation of the particles along the magnetic force lines.

2. Magnetic Fluid Grinding had been developed as a new process, which can remove materials more rapidly than the lapping process that is conventionally used. The MRF process relies on a unique "smart fluid" which changes viscosity and responds to external conditions. The fluid is a sherry of water and other materials, mainly carbonyl iron powder and an abrasive material, cerium oxide. Magnetic fluid grinding has been shown to be effective in grinding of ceramic balls, a metal cylinder end, a ceramic cylinder, ceramic rollers, ceramic plates and a metal pipe.

3. For the last few years, a new concept in finishing processes called Magnetic Abrasive Jet Machining has been being developed.

A schematic diagram of magnetic abrasive jet machining system consists of a fluid supply system, a nozzle, electromagnet parts, a power supply, a mixing chamber, discharge parts, and an abrasive tank. While machining, working fluid mixed with magnetic abrasives is jetted into the internal surface of the tube, with magnetic abrasives in the jetted mixed fluid are moved to the internal surface by magnetic force, where the magnetic abrasives finish the internal surface effectively and precisely.

4. Magnetorheological Abrasive Flow Finishing (MRAFF) is a novel precision finishing process developed at Indian Institute of Technology, for nanofinishing of complex internal geometries using smart magnetorheological polishing fluid. MRAFF process provides better in process control over rheological properties of abrasive laden magnetorheological finishing medium.

Table 1 [14] summarizes the essentials and the latest news on MAF, MRF and MJM and MRAFF. Table 1: Examples of MAF, MRF, MJM and MRAFF

processes

[1]

[2]

[3]

[4]

[5]

[6]


13

[7]

[8]

[9]

[10]

[11]

2. PHYSICAL MODELS OF MAGNETO-ABRASIVE FINISHING

In order to create a physical model for magneto-abrasive finishing when using magneto-abrasive grains, it started from the idea to make a full physical model specific for flat surfaces finishing which then it can be easily adopted for other types of exterior surfaces of revolution, interior revolution surfacesand even neanalitical.

The model is similar to that conducted by Iu. M. Baron [8] but it is supplemented by taking into account the frictional forces between the grains (fi) (Fig. 3.9) and the forces of interaction between them (Pi). Given the static situation when between the object that transfers the energy (OT) and processed object OP there is no relative motion (fig. 1) and the situation when between them there occurs speed V (figure 2).

It is assumed that the microcutting forces that appear due to contact between the powders and the processed surface are determined not only by the forces that act directly on the grains, but through the action of grains upon those surrounding them.

Considering an element of volume (DV) in the working area (ML) formed inside the working air gap (fig, 1), it will be calculated by generalizing the set of forces that appears.

The forces above are considered specific ones, acting on volume elements considered.

∑n

isp

i=1

∆FF =

∆V (1)

where: Fi – forces of the same nature that act upon "i" grains within the limits of volume V.

Figure 1. Physical model of MFA(static)


14

Figure 2. Physical model of MFA(motion )

Within the area occupied by the powder and on

the surfaces inside the working area it will be acted with normal and tangential forces, respectively normal and tangential strains:

∑n

Ni

i=1

σ =F

∆S ∑

nTi

i=1

Fτ =

∆S (2)

where: NiF and TiF are normal, respectively tangential forces that act upon a surface element ∆S .

It is assumed that the magnetic field is homogeneous on y and z axis, and inhomogeneous on x direction. It is considered that the magneto-abrasive powder is evenly distributed in the working area gap aa1, bb1, and that it is bounded by the law of magnetic pressure variation Pm.

In the presence of the magnetic field, the specific magnetic forces will act upon initial volumes in the working environment, creating σy and σz tensions.

y z z

µσ = ξ× σ = × σ

1 - µ (3)

where: ξ -lateral pressure ratio; µ - Poisson’s ratio for the working environment.

The tension σz, together with the specific forces FMsp, create pressures (Py) on the surfaces of the energy transfer object (OT) and on the processed object (OP), with the law of variation as shown in Figure 1.

Considering the equation F = 1 µ × V × B× B∇

and considering the relation ( )0P = µ × 1× r ×θ d results:

⋅ ⋅ ⋅ ⋅ ⋅∑∑ Mi

i

Msp

p p

VF 1 C δBF = = B B = B

∆V µ ∆V µ δn∇ (4)

where:

C - is the ratio between the volume content of the ferromagnetic and the abrasive constituents; µp - magnetic permeability of the powder for induction B, n - the direction of the magnetic induction gradient in the considered point.

Considering the relation (4), it can be determined the following components, respectively Fzsp and Fysp:

⋅ ⋅=p

zsp

C δBB

µ δzF ⋅ ⋅=

p

ysp

C δBB

µ δyF (5)

The concentration C is calculated with the relation:

∑ pi

M

γVC = =

∆V γ (6)

where: γp - specific weight of the abrasive powder; γM - compact grain specific weight (the part that contains both magnetic and abrasive contents).

Determination of lateral magnetic pressure PM requires considering the transfer of a small amount of �V material, from the separation line (Figure 1, on the right) bb1, from position I inside the working gap, to position II, outside its limits.

The magnetic energy of the volume will be modified without substantially changing the magnetic field distribution.

Specific magnetic energy of this volume, Wsp, will be calculated with the help of the equation (7) :

∑ 2 2

isp

0 0

V B BW = - × = -C×∆V 2× µ 2× µ

(7)

The magnetic pressure PM actually represents the

difference between the specific energies for the two positions I and II, respectively:

( )2 2M spc spi i e

0

CP = W -W = B - B2× µ

(8)

where Bi and Be are the values of magnetic induction corresponding to the two positions in any point of the line of separation.

Considering the relative movement of the processed object (OP), given the speed v, toward the subject of energy transfer (OT) and toward the working environment (ML), there will occure frictional forces and, in the same time, the forces pi and fi respectively the frictional forces between the grains and the interaction forces between these (figure 2).


15

Magneto-abrasive powder mass will assume a new position aa1bb1, leading to an increased pressure Py in the ad area.

Depending on the position of the grain, there can be determined the forces Fz and Fy acting on it:

( ) ( ) ( )

( ) ( ) ( )z

2y ysp ysp i

2zsp zsp i

∆SF g = F g × = F g × rN∆SF g = F g × = F g × rN

(9)

where: N = ∆S/r2 - the number of grains to be found in the surface element; r1 - grain radius [mm].

Separating a vertical column in the working environment, there can be determined the magnetic pressure Py that acts within the area:

( ) ( )

∫ ∫δ δ

y yspp0 0

2 2

yp p

C δyP = F × dy = × B× × dyµ δx

B δ; g B 0; gP = C× -

µ µ

(10)

If the magnetic induction B(δ;g) at the point of coordinates y=δ and z=g is higher than the magnetic induction B(0;g), then Py is positive and leaded toward the facing pole piece.

If B(0;g)>B(δ;g), then Py is negative and directed toward the work piece.

The link between Fz force and the internal friction forces and the interaction forces results from the equation:

⟩∑ ∑iz i ii i

BF × f × R + P × a

2 (11)

equation that if it is followed leads to the ending of the penetration of the grain’s peak in the work piece, with the quantity h and a new peak comes into action.

Abrasive cutting will be conditioned by the ratio h/g where g is the grain radius of the blunt tip.

In the case of a magnetic abrasive finishing process, a ferrofluid mixed with abrasive grains is used as a polishing compound. The physical model presented in this paper is shown in Figure 3.

Figure 3: Physical model of MFG

This process is based on the levitation property of non - ferromagnetic bodies sunken in a ferrofluid. The levitation occurs due to the force which a ferrofluid. placed into a magnetic field gradient, exerts upon these bodies. This force is oriented in an opposite direction to the gradient. The expression of electromagnetic levitation force depends on the shape of non - magnetic grains (spheres, revolution ellipsoids, cubes, cones, double cones, tetrahedrons) and on their orientation with respect to the coordinate axes.

The correct evaluations of the levitation force which acts upon a certain grain is quite a complex operation, because it must consider both the presence of the detached micro - chip, which can be magnetic or non -magnetic, and the properties of the involved ferrofluid. It is possible to determine experimental values for a correction coefficient that should be taken into account in the above mentioned situations.

A precise evaluation of the levitation force should use the complete system of equations from magne'e-hydrodynamics as well as the distortions that occur among the force assembly when introducing the abrasive grains.

A fluid suspension containing 30% SiC grains was used as a polishing compound.

The magneto - gravitational force acting upon grains immersed in ferrofluid is known to represent the force F resulting from combination of the magnetic force FMZ with the gravitational force FG, according to Figure 1:

G MZF + F + F = 0 (12) The force acting on the unit volume of a grain

placed in a ferrofluid is: ( )MZ 0 gF = µ M - M dH dz k (13)

where: M - ferrofluid magnetization; Mg - magnetization of the grain immersed in the ferrofluid; µ0 - magnetic permeability in vacuum. The levitation force, acting on non-magnetic grains immersed in the ferrofluid is:

∫r

0lk

g

µ dHF = M kdvV dz

(14)

where: Vg - the volume of the immersed grains; dH/dz – the magnetic field gradient; k

r - the unit vector.

Gravitational force acting on the unit volume of the grain in ferrofluid is:

( )G g fF = ρ - ρ × g× J (15) where: J - vertical unit vector.

The resultant force is give by Equation (16) and depends on the direction of action of the levitation forces.


16

The magneto - gravitational force F acts upon the grains in the ferrofluid, lifting them or bringing them down. This force needs an adequate change of the shape of polar piece or even of the entire finishing equipment.

( ) ( )g f 0 gdHFK + ρ - ρ gJ + µ M - M K = 0dz

(16)

3. CONCLUSIONS

The magnetic abrasive process is suitable for finishing very hard or heat-treated parts and shaping very hard non-metallic materials, such as ceramics and glass. In addition to inner surface tubing, magnetic abrasive finishing allows for more flexibility regarding the surface shape, which is applicable for the finishing of a complex part, because a clearance of several millimeters is permitted between the work and the pole. So although at present magnetic abrasive process is still at the level of research in labs, it has a great potential to be applied in industries.

In magnetorheological finishing, mechanical energy required for material removal over the portion of the work piece is generated by the magnetically controlled hydrodynamic flow of a magnetorheological polishing fluid.

A fundamental advantage of MRF over existing technologies is that this sub aperture polishing tool conforms to any surface and does not wear since the state of the recirculated fluid is continuously monitored and maintained.

MRF is enabling technology that may produce surface accuracy of the order of lOnm peak - to valley and surface microroughness less than 10 A.

Ferrofluids are colloidal suspension of surfactant - coated magnetic particles in a liquid medium, where the sizes of the particles are of several nanometers.

Magnetorheological fluid refers to a liquid similar to ferrofluid that solidify in the presence of a magnetic field. MR fluid have micrometer scale magnetic particles that are 1-3 order of magnitude larger than those of ferrofluids.

In contrast to know jet polishing method (magnetorheological jet finishing technology) is based on an assumption that the energy required for polishing may be supplied by the radial spread of a liquid jet over a surface to be polished. The round jet of magnetorheological (MR) fluid, containing abrasive particles, is magnetized by an axial magnetic field when it flow out of the nozzle. A local magnetic field induces longitudinal filer illation and high apparent viscosity within the MR fluid. It was established that MR jet finishing can produce high precision surfaces on the order of nanometers p-v with roughness < lnm rms.

REFERENCES [1]. Baron, Iu. M., “Magneto-abrasive machining of piece and

cutting tools”, Masinostroenije, 1986, Moskva [2]. Kurobe, T., Imanaka, O., Tachibana, S., “ Magnetic Field

Assisted Fine Finishing”, 1983, B.J.S.P.E, vol. 17, nr.l, pp.49-50

[3]. Childs, T.H.C., Mahmood, S., Joon, H.D., “Magnetic Fluid Guiding of Ceramic Balls”, Tribology International, vol.28, nr.6, pp.341-348, 1995

[4]. Umehara, N., Komanduri, R., “Magnetic Fluid Guiding of HIP-SI3N4 Rollers”, Wear, no. 192, pp.85-93, 1995

[5]. Fox, M., Agrawal, K., Shimeno, T., Komanduri, R., “Magnetic Abrasive Finishing of Rollers”, Annals of the C.I.R.P, vol. 43, pp.181-184, 1994

[6]. Umehara, N., Kobayaschi, T., Kato, K., “Internal Polishing of Tube with Magnetic Fluid Grinding. Part I: Fundamental Polishing Properties with Taper-Type Tools”, in Journal of Magnetism and Magnetic Materials, no. 149, pp. 180-184, 1995

[7]. Umehara, N., Kobayaschi, T., Kato, K.,” Internal Polishing of Tube with Magnetic Fluid Grinding. Part II: Fundamental Polishing Properties with Rotating Balls and with Oscillating Balls”, in Journal of Magnetism and Magnetic Materials, no. 149, pp. 185 -191, 1995

[8]. Shimura, T., “A New Process for Internal Finishing of Non-Ferromagnetic Tubing Using Rotating Magnetic Field”, Transaction of MAURI/SME; vol. XXI, pp. 1-13, 1993

[9]. Shimura, T., Yamaguchi, H., “A New Process for Internal Finishing of Tube by the Application of a Magnetic Field”, Journal of the Japan Society of Grinding Engineers, vol. 38, nr.l, pp. 15-18, 1994.

[10]. Kordonski, W., Golini, D., “Multiple Application of Magnetorheological Effect in High Precision Finishing”, Journal of Intelligent Material System and Structures, vol. 13, nr. 7-8, 401-404 pp, 2002.

[11]. Jha, B.H., Jain, V.K., “Design and development of MRAFF process”, International Journal of Machine Tools Manufacture, pp 1019-1029, 2004

[12]. Kordonski, W.I., Shorey, A.B., Tricard, M., “Magnetotheological Jet Technology”, Proceedings of IMECE 04, ASME International Engineering Congress, Anaheim, California, USA, 13-14 November, 2004

[13]. Ciobanu, M., “ Developments and Contributions Concerning the Optimization of Working Parameters in Magneto-Abrasive Finishing with Magnetic Fluid”, Ph.D. Thesis, Polytechnic Institute of Iasi, 1993

[14] Ciobanu, M., “Multiple application of magnetic abrasive finishing process”, Annals of MTeM for 2007 & Proceedings of the 8th International MTeM Conference, Cluj-Napoca, Romania, 101-104 pp, 2007

[15] Baron, Y.M., Ko,S.L., Park, J.I., “Characterization of the MAM and Its Applications to Deburing”, Key Engineering Materials, vol.2, pp 291-296., 2005

[16] Jha, B.H., “Design and development of MAF process”, International Journal of Machine Tools and Manufacture, Vol. 1, pp.101-109, 2004

[17] Kordonsky, W., “Multiple Application of MRF Effect in High Precision Finishing”, Journal of Intelligent Material System and Structure, Vol.13, pp. 401-404, 2002

[18] Sun, H.W., Yang, S.C., “Study of the finishing mechanism of fluid magnetic abrasive”, International Journal of Computer Application in Technology, nr. 2-4, pp. 141-144, 2007

[19] Wang, Y., Hu. D., “Study on the inner surface finishing of tubing by magnetic abrasive finishing”, International Journal of machine tools and manufacturing, vol.45, pp. 43-49, 2005.


17

ABRASIVE FINISHING IN MAGNETIC FIELD (A.F.M.F.) – AN EFFICIENT METHOD OF PROCESSING.

PART II: MATERIALS USED IN A.F.M.F..

Marius Băeşu1, Mircea Ciobanu2


REZUMAT Lucrarea prezintă o sinteză privind materialele utilizate in cadrul finisării abrasive în camp magnetic (AFMF). Astfel, sunt evidenţiate tipurile de materiale folosite în cadrul fiecăreia dintre variantele de finisare AFMF.Evoluţia materialelor utilizate în cadrul AFMF este continuă, în sensul că apar noi compoziţii de astfel de materiale. Principalul dezavantaj îl constituie costul lor, precum şi tehnologia relativ dificilă de obţinere. ABSTRACT This paper summarizes the materials used in the abrasive finishing in magnetic field (AFMF). Thus, there are highlighted types of materials used in each of the AFMF finishing variants. The evolution of materials used in AFMF is continuous, meaning that there are new compositions of such materials. The main disadvantage is their cost and relatively difficult to obtain technology. KEYWORDS: finishing, abrasive, materials, magnetic abrasive finishing. CUVINTE CHEIE: finisare, abraziv, materiale, finisare magneto-abrazivă.

1. INTRODUCTION The magneto-abrasive finishing is based on the

magnetic field capacity to lift and carry small grain particles, which must have magnetic and abrasive properties, between the poles of a magnetic system and the finished piece forming a so-called "magneto-abrasive brush "determined by the orientation of particles along the lines of magnetic force.

The magneto-abrasive finishing can be considered a subset of technological methods of dimensional processing with mass change that removes excess material in the form of chips or microchips.

The dimensional processing, by removing material, takes place by introducing a quantity of external energy in the processing area, in this case the energy inserted being a magnetic one and serves as a binder for the magneto-abrasive particles and, in the same time, exerts a pressure upon them.

Since the degree of elasticity of the binder is easily adjusted by changing the magnetic field strength, it is estimated that magneto-abrasive finishing is close to finishing with abrasive incorporated in frames, bars or blades.

It minimizes the possibility of microcracks on the

surface of the workpiece, particularly in hard brittle material, due to controlled low forces acting on abrasive particles [3]. This process is able to produce surface roughness of nanometer range on flat surfaces as well as internal and external cylindrical surfaces [3]. It can also be used for internal finishing of non-rotatable workpieces such as elbows and bent tubes [4]. The MAF process offers many advantages, such as self-sharpening, self-adaptability, controllability, and the finishing tools require neither compensation nor dressing [5].

In MAF, the workpiece is kept between the two poles of a magnet. The working gap between the workpiece and the magnet is filled with magnetic abrasive particles (MAPs) composed of ferromagnetic particles and abrasive powder. MAPs can be used as bonded or unbonded. Bonded MAPs are prepared by sintering of ferromagnetic particles and abrasive powder whereas unbonded MAPs are a mechanical mixture of ferromagnetic particles and abrasive powder with a small amount of lubricant [6,7,8]. The purpose of the lubricant is to provide some holding strength between the constituents of MAPs.


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The object of energy transfer (OT. Fig. 1) exerts a force or pressure upon the workpiece (WP), realizing the removal of micro-chips. All processing is performed in the working medium (WM).

The energy inserted into the working area causes basic processes with a continuing, cumulative and progressive character. It also causes state changes of the workpiece, of the working area and even of the object of energy transfer (the surfaces of the polar parts that come into contact with the workpiece).

Figure 1. The three elements of the MAF

The idea of using the power of a magnetic field for

machining belongs to Karlov, a Russian specialist who, in 1938[1, 3], proposed a model for finishing the inner surfaces of pipes using powders that possess magnetic and abrasive properties. The process was performed in an alternating magnetic field, changing the polarity cyclicly.

Mechanical mixtures of iron powders and abrasive materials, e.g. electrocorindon or cobalt-nickel alloys are inefficient, their abrasive characteristics being reduced.

As the magnetic part it is used iron or iron-cobalt alloy and as the abrasive part it can be used various oxides, synthetic diamond and some hard fusible compounds. Using one or another of the components must take into account their cost.

In recent years, it has become widespread, to use magneto-rheological environments (ferrofluid or magnetic fluid) to finish different materials in a magnetic field.

A variant of this method is the use of abrasive grains mixed with ferrofluids (electrocorindon, silicon carbide, industrial diamonds) based on the first degree levitation property of the ferrofluids and on the ferrofluids separators principle

Setting the maximum performance of these work mediums and improving the quality of the surfaces when processing with the help of these mediums imply an interdisciplinary research and a collaboration between metallurgy (powder metallurgy) and technology (machined specialists).

Table 1 describes the structural aspects, features, advantages and deficiences of working media used in magnetic abrasive finishing.

Table 1. Working media for MAF [9] Nr. crt Type Composition

1 Ferromagnetic - Ferroboron, - Ferrowolfram, - Chilled iron, etc.

2 Ferromagnetic matrix + abrasives

- Fe + TiC (15%) - Fe + WC (20%) - Fe + ZrC (10-20%) - Fe + Al2O3 (10-20%) - Fe + Cr3C2 (20-30%) - Fe + W2B5 (10-30%)

3 Ferromagnetic matrix + diamond grains

D = 100 250

µm

d = 5 40 µm

4 Ferrofluids + abrasives

- Ferrofluid • dispersing medium; • disperse phase; • stabilizing agent.

- Abrasives: • Al2O3; • TiC; • Cr3C2.

5 Magneto-rheological fluid + abrasives

- suspensions of magnetizable particles(carbonyl iron particle - CIP) - non-magnetic base liquid (natural oil, mineral oil, water or glycol)

In Table 2 there are presented different shapes of

the magneto abrasive particles (MAPs)or grains(MAGs) and their composition.

Table 2. Shapes and composition of MAPs/MAGs [1] Structural Issues

features Advantages Weaknesses

Homogeneous granular material (alloy or compound)..

- composition widely variable. - grain shape is variable, and its resistance is high.

- no cutting edges; - failure to ensure superior magnetic characteristics; - reduced cutting capacity.

Grains with relatively symmetric radials arranged abrasive part.

- high cutting capacity; - good magnetic characteristics; - possibility of self sharpening.

- the cutting capacity is limited by the melting temperature of the material and therefore the grain has a lower resistance; - there is a


19

Structural Issues features Advantages Weaknesses

Sharp abrasive component which consists of a housing in which the composite material is found.

- superior dispersion of the abrasive; - high resistance - good grinding capacity due to better dispersion.

decrease in the magnetic characteristics of grain due to abrasive compounds.

Monolayer type ferromagnetic compound with abrasive embedded in the surface .

- the magnetic characteristics of grain are increasing; - the cutting capacity is significantly increasing

- the destruction speed of the abrasive layer is high - the strength of the powder is reduced.

Monolayer ferromagnetic compound with abrasive in depth.

- superior magnetic characteristics; - high resistance.

- there is a decrease in the magnetic characteristics of the powder.

Ferromagnetic material covered by a hard abrasive film.

- superior magnetic characteristics;

- lack of contact with the machined surface.

- due to the lack of cutting edge, the cutting capacity is reduced.

Ordinary fluids do not have suitable magnetic

properties to be handled easily by the action of a magnetic field. A liquid medium with such properties have great practical interest, therefore, more than two decades ago, NASA first synthesized magnetic liquids, ultrastable colloidal suspensions of magnetic particles, which in a first approximation, behaves as a cvasihomogeneous liquid with relatively high magnetic susceptibility.

Ferrofluids (FF) are suspensions of small magnetic particles with a mean diameter of about 10 nm in appropriate carrier liquids. The particles contain only a single magnetic domain and can thus be treated as small thermally agitated permanent magnets in a carrier liquid [10].

The special feature of FF is the combination of normal liquid behavior with superparamagnetic properties. Moreover, some properties like the viscosity, the phase behavior, or their optical birefringence properties, can be changed by applying an external magnetic field [11].

The magnetic fliquids or ferrofluids (also called magnetic fluids) have three main components: liquid base (in principle any liquid), ultrafine magnetic particles (typically, Fe3O4, Fe or Co) and stabilizer (a long chain surfactant) covering each particle with a monomolecular layer.

Due to the very small size of magnetic particles (≤ A) and soluble stabilizer layer in the liquid base, the particles practically integrate in liquid structure, which confers the properties of a "magnetic fluid", even in the presence of a strong and uneven magnetic field, with a destabilized action on any ordinary magnetic suspension.

The synthesis of ferrofluids has two main steps: (a) the preparation of nanosized magnetic particles (2-15 nm) and (b) the subsequent dispersion/stabilization of the nanoparticles in various non-polar and polar carrier liquids. In what concerns the ferrite nanoparticles, the most efficient route is the chemical co-precipitation process [12].

Depending on the carrier properties and applications envisaged, different procedures of ferrofluid synthesis were developed.

The magneto-rheological fluid consists of: a). Carrier fluid. b). Ferrous particles with micrometer diameter,

with a concentration of 30-40% by volume. c). Surface-active additives used to prevent the

particle fixation (antiflocculating material). There are three types of carrier fluid, based on: - hidrocarbonate oils; - Silicone oil; - Water. When exposed to a magnetic field, the ferrous

particles in the fluid settle in columnar structures formed along the lines of the magnetic flux.

These columnar structures can cause a major change in the properties of the fluid, determining an effective transformation of the fluid into a semisolid.

The magnetic field changes the shear strength value of the magneto-rheological fluid (MR) meaning that the shear strength increases in the same time with the intensity of the magnetic field.

The magneto-rheological fluids are colloidal suspensions of non-ferrous particles. If these fluids are not subject to the action of a magnetic field, they have a Newtonian fluid behavior similar to ferrous hydraulic fluids dispersed and they form magnetic dipoles.

The variation of the intensity of the magnetic field leads to changes of the apparent viscosity of the magneto-rheological fluid (viscosity change does not occur as defined, but the mix represented by MR fluid meets, becoming semisolid, under the action of a magnetic field).


20

The action of the magnetic field increases the shear resistance.

The higher the intensity of the magnetic field, the higher the resistance of the flow in its areas of action (until reaching the center of saturation) the saturation occurs when any increase of the current is not followed by an increase of the magnetic forces in the fluid [13].

Magneto-rheological fluids are capable to develop large forces in magnetic field active regions,because the flow resistance in those areas is high.

In general, an MR fluid finishing process (Fig. 2) uses the controllability of the fluid rheological characteristics via an external magnetic field. First, the MR fluid is mixed properly with hard, non-magnetizable abrasives, such as diamond, silicon carbide, or aluminum oxide powders (in cases where the polishing of glass or silicon is needed, chemically active abrasives are often mixed solely or additionally), which are then pushed into the interface through a nozzle between the workpiece and the permanent or electromagnetic tool surfaces moving against each other. The magnetic buoyancy force caused by the gradient of the magnetic field intensity continuously pushes internal abrasives outward to the surface. Abrasives on the surface are then exerted by the MR fluid and join the surrounding CI particles (the main ingredient of the MR fluid) to abrade the workpiece surface with a given pressure and velocity, and material removal occurs on asperities when the induced stress applied to an asperity exceeds the yield stress and causes a plastic flow.

Figure 2. Conventional MRF processes with (a) non-magnetizable abrasives, and (b) conventional MRF processes with magnetizable abrasives [15]

3. CONCLUSIONS

The paper presented a summary of the types of materials used in AFMF and find that their evolution is continuous, meaning that there are new and new compositions of such materials.

The main disadvantage is related to their cost and relatively difficult to obtain technology.

REFERENCES [1]. Baron, Iu. M., “Magneto-abrasive machining of piece and

cutting tools”, Masinostroenije, 1986, Moskva [2]. Baron, Iu. M., Ko, S. -L., Park, J. I., “Technique of Comparison and Optimization of Conditions for Magnetic

Abrasive Finishing”, Key Engineering Materials, Vols. 291-292, pp. 297-302, 2005

[3]. Jain, V.K., “Advanced machining processes”, Allied Publishers, 2002, Delhi

[4]. Jain , V.K., Kumar, P., Behra, P.K., Jayswal, S. C., Effect of workinggap and cicumferential speed on the performance of magnetic abrasive finishing process”, Wear Elsevier, vol. 250, pp. 384–390, 2001

[5]. Yamguchi, H., Shinmura, T., “Study of surface modification resulting from an internal magnetic abrasive finishing”, Wear Elsevier, vol. 225, pp. 246–255, 1999

[6]. Chang, G.W., Yan, B.H., Hsu, R.T., “Study on cylindrical magnetic abrasive finishing using unbonded magnetic abrasives”, Int. J. Mach. Tools, Manuf ., vol. 42, pp. 575–583, 2002

[7]. Shinmura, T., Takazawa, K., Hatano, E., “Study on magnetic abrasive finishing-effects of machining fluid on finishing characteristics”, Bull Japan Soc Precis. Eng ., vol. 20(1), pp. 52–54, 1986

[8]. Jayswal, S.C., Jain, V.K., Dixit, P.M., “Modeling and simulation of magnetic abrasive finishing process”, Int. J. Adv. Manuf. Technol.,vol. 26, pp. 477–490, 2005

[9]. Ciobanu, M., “ Developments and Contributions Concerning the Optimization of Working Parameters in Magneto-Abrasive Finishing with Magnetic Fluid”, Ph.D. Thesis, Polytechnic Institute of Iasi, 1993

[10]. Holm, C., Weis, J.-J., “The structure of ferrofluids: A status report”, Current Opinion in Colloid & Interface Science, vol. 10, pp. 133 – 140, 2005

[11]. Zubarev, A.Yu., IskakovaJha, L.Yu., “Rheological properties of ferrofluids with drop-like aggregates”, Physica, vol. A 376, pp. 38–50, 2007

[12]. Vékás, L., “FERROFLUIDS. Synthesis, properties and applications”, European Summer School on Magnetism - New magnetic materials and their applications , Cluj Napoca, Romania, 2007

[13]. Shiraishi, T., Morishita, S., Gavin, H.P., “ Estimation of equivalent permeability in magnetorheological fluid considering cluster formation of particles”, Journal of Applied Mechanics, vol. 71, pp. 201-207, 2004

[14] Sadiq, A., Shunmugam, M.S., “A novel method to improve finish on non-magnetic surfaces in magneto-rheological abrasive honing process”, Tribology International, vol. 43, pp. 1122-1126, 2010

[15] Jang, K.-I., Seok, J., Min, B.-K., Lee, S.-J., “An electrochemomechanical polishing process using magnetorheological fluid”, International Journal of Machine Tools & Manufacture, vol. 50, pp. 869–881, 2010


21

3D ABRASIVE WATERJET CUTTING AND MECHANICAL MACHINING EQUIPMENT

Cristian Birtu1, Valeriu Avramescu1, Roxana Grejdănescu1

1 S.C. ICTCM S.A. Bucharest, ROMANIA,

e-mail: [email protected], [email protected],[email protected]

REZUMAT Lucrarea prezintă realizarea din cadrul unui proiect, ce are ca scop principal dezvoltarea şi implementarea utilizării unui echipament modular complex, dedicat operaţiilor de prelucrare convenţionale şi neconvenţionale, pe aceeaşi maşină, pentru producţia curentă a beneficiarului şi, de asemenea, pentru pregătirea celor care vor fi asimilate. Cercetările se bazează pe realizarea unui echipament de prelucrare cu jet hidroabraziv şi prin aschiere în 3D, care este destinat pentru prelucrarea, pe acelaşi utilaj, a materialelor, prin două metode tehnologice: tăiere cu jet hidroabraziv şi prelucrare prin aşchiere (găurire).

ABSTRACT The paper presents a project achievement, which has as a main goal the development and the usage implementation of a complex/module equipment, which is dedicated to the conventional and nonconventional processing operations, on the same machine, for the current production of the beneficiary and also for the preparation for the ones which will be assimilated. Researches are based on the achievement of 3D abrasive waterjet cutting and mechanical machining equipment, which is designed to manufacture of materials using two technologies on the same equipment: waterjet cutting and mechanical machining (drilling). KEYWORDS: abrasive waterjet, 3D manufacturing, cutting, drilling CUVINTE CHEIE: jet hidroabraziv, prelucrare 3D, tăiere, găurire

1. INTRODUCTION

The paper presents a project achievement, which has as a main goal the development and the usage implementation of a complex/module equipment, which is dedicated to the conventional and nonconventional processing operations, on the same machine, for the current production of the beneficiary and also for the preparation for the ones which will be assimilated.

The main propose of the project is to develop the technological capacity of a small enterprise which activates in the production area, by assimilating in production the applicative results, which are developed by the project coordinator, the progress of the project’s specific activities being made in partnership by the ones mentioned above and a competent center from an educational institution.

Another purpose is to increase the competition of

the industrial partner and also its capacity to create new products or to offer new technological services in its activity area.

Researches are based on the achievement of 3D abrasive waterjet cutting and mechanical machining equipment, which is designed to manufacture of materials using two technologies on the same equipment: waterjet cutting and mechanical machinning (drilling), [1].

2. INNOVATIVE ASPECTS AND EQUIPMENT COMPETITIVENESS A. Innovative aspects of the equipment There are presented equipment innovative aspects:


22

• There are known equipment for water jet cutting and equipment for machining (boring and milling) which are manufacturing parts and/or subassemblies with complex shapes in 3D successively;

• The disadvantages of these manufacturing methods applied successively on the same part are: - the positioning and orientation errors of the

part are accumulating when the part is transferred from one equipment to another one;

- the positioning and orientation time is accumulating;

• The method of combined manufacturing of parts with water jet and machining technologies on the same equipment avoid above mentioned disadvantages as follows: - the part is oriented and clamped on the work

table of the equipment one time only; - all needed manufacturing operations (water jet cutting, boring etc) are performed successive, without other human intervention / process interuption; B. Competitiveness of the equipment The competitivness of the technical solution is sustained by the following considerations: • Technological flexibility: the equipment was

designed to comply with requests of every small or medium company shop floor, for water jet cutting and machining of materials as aluminum, steel, waterproof steel, wood or granite;

• Increased quality of manufacturing operations; • Flexibility for manufactured part shape;

3. EQUIPMENT CONFIGURATION

The equipment consist of the following functional units (figure 1):

1. – Waterjet cutting and mechanical machining table with CNC command; 2. – CNC command unit; 3. – Very high pressure unit. Figure 2 presents a general view of Waterjet

cutting and mechanical machining table with CNC command. The notations have the following meaning: 1. – longitudinal slide X; 2. – cross slide Y; 3 – vertical slide Z.

Figure 1. 3D abrasive waterjet cutting and mechanical machining equipment


23

Figure 2. Waterjet cutting and mechanical machining table with CNC command – general view

Figure 3. Very high pressure unit Figure 4. Vertical slide Z

Figure 3 presents the very high pressure unit and figure 4 presents vertical slide Z.

The notations have the following meaning:

1- mechanical machinning head (drilling); 2 – waterjet cutting head. There are presented main equipment’s technical characteristiques:

- maximum (longitudinal x cross x vertical) strokes: … 1500 x 1000 x 200 mm; - working table’s surface: ... 1800 x 1600 mm; - longitudinal / cross speeds (max.): ... 10 m/min; - vertical speed (max): ... 0,22 m/min; - water jet cutting pressure (max).: ... 4000 bar; - cutting water flow (max.): ... 1,2 l / min; - motor of mechanical machining tool (380 V/50 Hz): ... 750 W / 2950 rot/min; - X, Y and Z axes servo-motors: ... 660 W/2,1 Nm;

12


24

- vertical feed force (max.): ... 5000 N; - boring diameter max. (carbon steel): ... Ø10 mm; - water jet cutting depth max. (carbon steel)... 20 mm.

The proposed technology has as components the following elements:

- cutting equipment with hydrobrasive jet; - subassembly for cutting processing, which is put in the cutting head’s place; - subassembly for water and abrasive material filtering and recovery; - devices/subassemblies for transfer, processed products positioning.

Regarding the equipment, water jet cutting machine was conceived to be perfectly displaced in any workshop where there are accomplished cutting operations in materials as: aluminium, steel, stainless steel, but also the wood and the granite. More then the fact that there are possible cuttings for various structures of materials, the cuttings’ quality is bigger and faster.

4. CONCLUSIONS. ESTIMATION OF

ECONOMICAL RESULTS

The proposed technology’s advantages comparing with the nowadays national technologies are the following:

• Flexibility and increased productivity; • Don’t result residual waters, chemically polluted; • Technology easy to be automated, with simple

equipments for international transfer. The originality level of the adopted solution is

proved by the following aspects:

• A new combined equipment, which allows the achievement in the same post of two technological, conventional and unconventional, operations;

• The conceiving of a flexible cutting technological cell; • The conceiving of a technology optimized from the

material and financial fluxes point of view, moduled in the same time and easy to be automated.

The technology, proposed to be achieved in this

project, has a high complexity level, resolving by a compact technological line, problems related to: processing profiled 3D by two different technologies (cutting with hydroabrasive jet and normal cutting), technologic transfer, water jet filtering and greening.

Estimate of economical results

Estimated economical efects/results for the user/owner of this combined technology equipment comparing with users of two special equipments for each technology (waterjet cutting and mechanical machining) are the following:

• Increase of market offered product range, both

for actual and perspective products); • Possibility to offer of customer personalised

products; • Possibility to realise and implement in

production/on market new products, with new design;

• Decrease of manufacturing cost with 10.. 15%; • Increase of product port-folio with 10%; • Increase the overall product quality.

REFERENCES [1]. Technology and equipment for processing with

hydro abrasive jet and by 3D CNC cutting, http://www.ictcm.ro/pncdi2007_2008/2008_tehjet3d/en-pncdi/index.html.


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METHODOLOGY OF MONITORING THE LOADINGS ON THE JAW CHUCK FOR DRILLING AND MILLING

PROCESSING

Raluca Magdalena Nita1, Adrian Ghionea2, Florin Sabou3

1 S.C. ICTCM S.A. - Mechanical Engineering And Research Institute, Faculty Engineering and Technological

System Management, University Politehnica Of Bucharest, ROMANIA, PDH student, e-mail: ralu_magda.yahoo.com

2 Prof. PHD Eng., Engineering and Technological System Management, University Politehnica of Bucharest, ROMANIA

3 Universität Stuttgart, Institut für Werkzeugmaschinen, GERMANY

REZUMAT În lucrare sunt prezentate etapele pregătirii ansamblului sistemului tehnologic maşina-unealtă-dispozitiv-sculă-piesă în vederea implementării unui sistem de achiziţie de date pentru înregistrarea forţelor şi momentelor de aşchiere pe cele trei direcţii principale Fx, Fy şi Fz şi a momentului Mz, în timpul prelucrărilor de găurire, lărgire şi frezare laterală. În timpul cercetărilor experimentale au fost utilizate trei piese din materiale diferite: aluminiu, ST52 şi 42MoCrV. De asemenea lucrarea propune o metodologie de monitorizare a unui dispozitiv de fixare cu bacuri, în vederea integrării acestuia in sistemele de producţie avansate. ABSTRACT In this paper are presented the stages of preparing the technological system machine-tool-device-tool-work-piece assembly in order to implement a data acquisition system for recording the cutting forces on the principal orthogonal directions Fx, Fy, Fz and the cutting momentum Mz, during drilling, enlarging and lateral milling. During experimental researches were used three work-pieces from different materials: aluminum, ST52 and 42MoCrV. The paper also presents a methodology of monitoring for a jaw fixing device, for its integration in an advanced production system.

KEYWORDS: mechatronic device, sensors, transductors, monitoring system, advanced production system CUVINTE CHEIE: dispozitiv mecatronic, senzori, traductoare, sistem de monitorizare, sistem de productie avansat

1. THE CONCEPT OF MECHATRONIC FIXING SYSTEM The development of different technologies beaded to the productions technologies leaded to the improvement of automation, flexibility [1, 2, 3] and productivity [4] increasing. The monitoring strategies have developed on the data transmission but also on them processing [5, 6]. An important role in the technologic system is given to the clamping device of

the work-piece and/or the tool. These are equipped with one or more sensors [7, 8]. Researches in the domain had leaded to the adaptronic system that assures an autonomous and adaptive control of the process and of the cutting conditions, and also a static and dynamic compensation of the errors that appears during processing [9, 10]. When a work piece is it positioned and fixed with the help of a device with sensors the dynamic response of the system could be used for the characterization of the fixing state, because when the contact between the work-piece and the devices


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modify, the answer of the system will correspondently modify. The sensors and the transductors in which they are included have the role of taking over the primer information referring to the achieved measures from the systems, measures that in general are not electric and to convert them in an electric one.

The variety of sensors is very large because, on a hand, it exist a great number of measurable measures, and on the other hand, for every measurable measure, could exist different methods of measuring, in concordance with the phenomena on which the conversion it is based.

The mechatronic orientation and fixing, figure 1, have the possibility to modify the behavior as an adaptation to the modifications from the process. Such systems it can be considered intelligent.

Through intelligence it can be understood them capacity to achieve a certain scope and to have a specific behavior in uncertain situations, in others words in the moments that appears unexpected or unpredictable events and also uncompleted and insufficient information for deciding what it should be done.

Figure 1. Mechatronic fixing system In the analyzed situation the included

intelligence in an orientation fixing systems has the role to improve its functional performances, to make the assembly machine-tool-device easier to use, in higher condition of precision and safety. 2. DEVICES, EXPERIMENTATION, DATA ACQUISITION AND DATA PROCESSING

The presented researches were done at Universtät Stuttgart, Institut fur Werkzeugmaschinen, Deutchland. These researches are based theoretical studies and experimental researches in the domain of orientation and clamping systems for the work-pieces.

The experimental researches had taken into consideration the mechanical part of the devices, as components of the complex processing systems, as CN machine-tools.

As a first stage of the experiments we analyzed the technologic possibilities of the work-piece processing, the monitoring and the data acquisitions for the processes parameters. The preparing the system MTDWT was realized taking into consideration the adjustment and programming the used machine-tools, the orientation and fixing of the work-pieces, tools adjustment

The schematic representations of the activities before processing the work-pieces it is represented in figure2. For processing the work piece was used a CN machine-tool, a milling center produced by Hermle.

Figure 2. Experimental setup

For the data acquisition during the processing of the work-piece were create an experimental montage using a Kistler 9272 dynamometer, which was mounted directly on the work-piece table. So, was realized an experimental montage represented in figure 3. For the date acquisition and recode was also used a data acquisition board, a multiplexor for multichannel recording, a PC with Windows XP, a LABVIEW interface.

The Kistler 9272 dynamometer represented in figure 4, is an equipment capable of recording the signals and four channels in order to give information about the cutting momentum Mz and cutting forces on the 3 orthogonal directions Fx, Fy and Fz.

The half finished product is a bar of 40mm and a diameter of 70mm. For comparison the cutting forces and momentum, as loadings elements, were used different type of materials, such as aluminum, ST52 and 42MoCrV.


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Figure 3. Preparing the technologic system

Figure 4. Kistler Dynamometer

The clamping device used for the orientation and fixing of the device is one from Röhm, precisely a 3 jaw chuck.

A sketch of the proposed work-piece represented in figure. 5, are distinctly marked the surfaces realized through drilling, enlarging and lateral milling. For the specification of the orientation and fixing of the half-finished products in the operating plan (O.P.) and for the identification and location construction was necessary to use the informational symbolization, which operates with suggestive graphic signs. From functional-cinematic information points of view are specified the number of discharged freedom degrees for every surface, the surface type and orientation.

The experimental results recorded during processing are represented in the figures 6-23, and include the forces on the principal directions Fx, Fy and Fz, and respectively Mz, for every of the 3 materials and the applied technological proceedings.

Figure 5. Proposed work-piece

Figure 6. Cutting force for aluminum drilling


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Figure 7. Cutting momentum for aluminum drilling

Figure 8. Cutting forces for aluminum enlarging

Figure 9. Cutting momentum for aluminum enlarging

Figure 10. Cutting forces for aluminum lateral milling

Figure 11. Cutting momentum for aluminum lateral milling

Figure 12. Cutting forces for ST52 drilling

Figure 13. Cutting momentum for ST52 drilling

Figure 14.Cutting forces for ST52 enlarging


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Figure 15. Cutting momentum for ST52 enlarging

Figure 16. Cutting forces for ST52 lateral milling

Figure 17. Cutting momentum for ST52 lateral milling

Figure 18. Cutting forces for 42MoCrV drilling

Figure 19. Cutting momentum for 42MoCrV drilling

Figure 20. Cutting forces for 42MoCrV enlarging

Figure 21. Cutting momentum for 42MoCrV enlarging

Figure 22. Cutting forces for 42MoCrV lateral milling

Figure 23. Cutting momentum for 42MoCrV lateral milling


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3. METHODOLOGY FOR THE COMMAND AND MONITORING OF A FIXING DEVICE WITH JWAS

The device integration in an advanced production system means taken into consideration of two important aspects for its functioning, on a hand the spatial integration, that means establishing links with the electric and mechanical part, and on the other hand functional integration, represented by the two systems links with the informatics part.

The device integration in the production advanced systems means a permanent link of all these with the equipments that are component of the respective system. This fact involves beside the existence of the classic device structure also data acquisition and data processing systems, command and control systems, all this equipments leading to the existence of some process monitoring systems. After analyzing of the experimental results and taking into consideration the actual trend of improving the intelligence of the devices we consider that is important to elaborate a methodology of active monitoring in real time of the entire processing.

The proposed methodology starts with measuring the cutting forces on the orthogonal directions and the cutting momentum Mz. The data recorded during the cutting process with the help of the data acquisition system are saved in a text file. This data are read and transformed in a excel format, as shown in figure 24.

Figure 24. Necessary clamping force calculation

In figure 25 is presented the methodology of

calculation of the necessary clamping force that it should be developed by the clamping system.

Because of this it was necessary to create a computer program - MathCAD programming language, which contains as input the size and the material characteristics of the work-piece, the forces and the moments acquired during the processing and also the construction characteristics of the device.

The final result of calculation is needed to determine the clamping force. In order to increase reliability, improve accuracy of processing is necessary to compare the data obtained calculating with the actual clamping force, measured during processing. Reason for we propose the creation of an experimental assembly similar with the one in figure 26.

On the jaws used for clamping the piece is mounted a force transducer, which records the amount of clamping force via the data acquisition system. In a comparison program are read on the one hand the necessary clamping force values, and on the other the value of real clamping force, ensured by the fixture.

When clamping force value assured by the fixture is less than the required clamping force due to actual processing conditions is indicated the existence of the possibility of modifying the processing parameters.

Because of the complexity of the control programs in the machine code language, this is difficult to realize. A simpler solution would be establishing a protocol of communication with the machine-tool command system, to stop it when the safety processing conditions are not ensured.

Figure 25. Methodology of calculating the necessary clamping force


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Figure 26. Methodology for the command and monitoring of a fixing device with jaws

CONCLUSIONS

The methodology for monitoring of a fixing device with jaws proposed in this paper brings a contribution the integration of this kind of device in an advanced production system.

In the proposed methodology are taken into consideration two important aspects of the integration, namely and spatial and functional integration.

From spatial integration point of view the methodology proposes the link between the electrical and mechanical, and from functional point of view the link between informatics systems and mechanical and electrical part.

By applying this methodology is respected the current trend of increasing the intelligence of devices, by implementing a process for real-time monitoring and establishing, in real time, a protocol for communication with the entire production system. ACKNOWLEDGEMENTS The work has been funded by the Sectoral Operational Programme Human Resources Development 2007-2013 of the Romanian Ministry of Labour, Family and Social Protection through the Financial Agreement POSDRU/6/1.5/S/16. I also thanks to Mr. Florin Sabou, diplomat engineer at Universtät Stuttgart, Deutchland, Institut fur Werkzeugmaschinen, for his help in conducting these experiments.

REFERENCES [1] Wiendahl H-P, ElMaraghy HA, Nyhuis P, Za¨h MF, Wiendahl H-H, Duffie N, Brieke M. (2007) Changeable Manufacturing—Classification Design and Operation. Annals of the CIRP Manufacturing Technology, 56 (2). p. 783–809. [2] Moriwaki T. (2008) Multi-functional Machine Tool .Annals of the CIRP Manufacturing Technology, 57 (2). p. 736–749. [3] Koren Y, Heisel U, Jovane F, Moriwaki T, Pritschow G, Ulsoy G, van Brussel H. (2008) Reconfigurable Manufacturing Systems Annals of the CIRP Manufacturingn Technology, 48 (2). p. 527–540. [4] Byrne G, Dornfeld D, Denkena B. (2003) Advancing Cutting Technology Annals of the CIRP Manufacturing Technology, 52 (2). p. 483. [5] Lapp C (2002) Identifikation und Regelung von Bearbeitungskra¨ften an direkt getriebenen Vorschubeinheiten, Dr.-Ing. Dissertation, University of Hannover. [6] Pritschow G, Fritz S (2004) Rekonstruktion von Prozesskra¨ften bei Direktantrieben unter Verwendung des Ferraris-Sensors. Autonome Produktion, Springer, Berlin. [7] Tonshoff HK, Inasaki I (2001) Sensors in Manufacturing. Wiley-VCH. ISBN 3-527r-r29558-5. [8] Byrne G, Dornfeld D, Inasaki I, Ketteler G, Konig W, Teti R. (1995) Tool Condition Monitoring (TCM) The Status of Research and Industrial Application Annals of the CIRP Manufacturing Technology, 44 (2). p. 541–567 [9] Neugebauer R, Denkena B, Wegener K. (2007) Mechatronic Systems for Machine Tools Annals of the CIRP Manufacturing Technology, 56 (2). p. 657–686. [10] Janocha H (2007) Adaptronics and Smart Structures: Basics, Materials, Design and Applications. Springer, Berlin.


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Quick Info Regional Innovation Monitor - platform is online! The Regional Innovation Monitor (RIM) is an initiative of the European Commission's Directorate General for Enterprise and Industry, which has the objective to describe and analyse innovation policy trends across EU regions. RIM covers EU-20 Member States: Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, the Netherlands, Poland, Portugal, Romania, Slovakia, Spain, Sweden, UK. The project is based on methodologies developed in the context of the INNO-Policy Trendchart which covers innovation policies at national level as part of the PRO INNO Europe initiative. Those interested in regional innovation policies can create an account giving them priviliged access to a collaborative platform.

In line with Europe 2020, the EU’s strategy for smart, sustainable and inclusive growth, the Directorate General Enterprise and Industry is working towards five general objectives: to strengthen Europe's industrial base and promote the transition to a low carbon economy; to promote innovation as a means to generate new sources of growth and meet societal needs; to encourage the creation and growth of SMEs and promote an entrepreneurial culture; to ensure an open internal market for goods; and to support the European presence in space.

The Directorate General (DG) has a key role to play in the implementation of Europe 2020. It is responsible for two of the seven flagship initiatives:

• "An industrial policy for the globalisation era" to improve the business environment, notably for SMEs, and to support the development of a strong and sustainable industrial base able to compete globally, and

• "Innovation Union" to improve framework conditions and access to finance for research and innovation so as to ensure that innovative ideas can be turned into products and services that create growth and jobs.

Both of these initiatives are crucial to help set Europe on the right track to becoming a more competitive, innovative and resource-efficient economy, ready to tackle today's and tomorrow's challenges.

As outlined in the Commission's Work Programme, the DG is working on a number of measures to deliver Europe 2020 in the enterprise and industry policy area.

In the context of ensuring a well-functioning internal market for goods, the DG will also continue its day-to-day management of legislation governing the placing of products on the market. This ensures the free movement of goods while taking into account the need for safety and to protect the environment. Information on all the legislation by sector is contained in an information tool known as “The Pink Book” which is updated yearly with all the latest legislative developments. The most recent edition [408 KB] covers the period up to 31 December 2009.

DG Enterprise and Industry employs around 1,000 people in its departments and units [21 KB] and is responsible for a budget of some € 1.5 billion.

An Annual Activity Report presents how the DG's work has been carried out in any given year and follows up on the annual work programme. In it, the Director-General reports on his duties as authorising officer and details how the budget was spent. Evaluations are also done regularly to determine the effectiveness of the projects undertaken.

(source: http://ec.europa.eu/enterprise/dg/index_en.htm)


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TEHNOLOGIE PENTRU SORTAREA SI MARUNTIREA DESEURILOR POLIMERICE COMPOZITE.

REALIZAREA UNEI FRACTII DE RECICLAT DE INALTA CALITATE, DESTINATA REUTILIZARII IN PROCESUL

DE FABRICATIE

Avramescu Valeriu1, Paun Loredana Theodora1, Teodorescu Florin1, Dumitru Condurache1, Rosu Dorin2, Nita Raluca Magdalena1, Teodorescu Horatiu3

1Mechanical Engineering and Research Institute, Bucharest, ROMANIA, [email protected]

1Mechanical Engineering and Research Institute, Bucharest, ROMANIA, [email protected] 1Mechanical Engineering and Research Institute, Bucharest, ROMANIA, [email protected] 1Mechanical Engineering and Research Institute, Bucharest, ROMANIA, [email protected]

2Compozite Ltd, Brasov, ROMANIA, [email protected] 1Mechanical Engineering and Research Institute, Bucharest, ROMANIA, [email protected]

3Transilvania University, Brasov, ROMANIA, [email protected]

REZUMAT Lucrarea prezinta o tehnologie pentru pentru sortarea şi mărunţirea deşeurilor polimerice compozite şi realizarea unei fracţii de reciclat de înaltă calitate prin recuperarea mecanică a fibrelor de sticlă şi/sau de carbon, destinată reutilizării acestora în procesul de fabricaţie al structurilor din materiale compozite. Problema tehnică pe care o rezolvă tehnologia este recuperarea mecanică a fibrelor de sticlă şi/sau de carbon odată cu mărunţirea structurilor de materiale compozite şi sortarea acestora, cu ajutorul unor echipamente speciale de decojire, defibrilare şi recuperare. ABSTRACT This paper presents a technology for sorting and crumbling of waste polymer composites and achieving a high quality recycled fractions by mechanical recovery of glass and/or carbon, for their reuse in the manufacturing of composite structures. The technical problem is solved by the technology of glass mechanical recovery and/or shredding carbon structures with composite materials and sorting them by means of special equipment for peeling, defibrillation and recovery. KEYWORDS: recycling, composite materials, fraction, sorting, crumbling, recovery CUVINTE CHEIE: reciclare, materiale compozite, fractie, sortare, maruntire, recuperare

1. INTRODUCERE

In general la reciclarea materialelor polimerice compozite apar dificultati deosebite deoarece materialele polimerice reprezinta o gama de materiale foarte variate. In prezent sunt fabricate peste 50 de tipuri de rasini polimerice care pot fi sau nu armate cu fibre -in mod predominant termoplaste (polipropilena, polistirenul, policlorura de vinil, pliamide, poliester si poliuretan).

Aceste rasini termoplaste pot fi retopite (si regranulate) si reutilizate prin compoundare (amestecare) cu materialul nou. Rasinile duroplaste insa nu mai sunt fuzibile si ca atare acestea (rasinile poliestarice nesaturate, rasinile vinilice, epoxi, fenolice) trebuiesc reciclate prin selctare si maruntire.

Materialele compozite polimerice sunt materiale care nu pot fi depozitate in locuri obisnuite, la ora actuala toate firmele de gestionare a deseurilor refuza


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sa rdicice deseurile de materiale polimerice compozite.

Nu exista la nivel national o strategie de protectie a mediului prin inglobarea materialelor polimerice compozite intr-un program gestionare a acestor tipuri de deseuri. Ca urmare aceste deseuri raman la producatorii de piese specifice din material polimeric compozit unde se aduna in locuri special amenajate din incinta intreprinderilor.

O reciclare 100% nu este insa posibila. Probleme apar la proasta sortare a fractiilor, precum si la presare. Fractia de dimensiuni mari se foloseste, de obicei, armarea pieselor din materiale compozite termorigide precum SMC, sau BMC, dar si la inglobarea in structuri din industria de constructii.

Tehnologia de reciclare cuprinde: livrare deseuri si separare; selectare si sortare deseuri; alimentare pentru instalatia de maruntire (utilaj tip shredder), maruntire si filtrare, compactare, livrarea reciclantului pentru refolosire la firme de constructii specializate. Se cunosc tehnologii şi echipamente de sortare şi mărunţire a deşeurilor compozite cu realizarea de fracţii de reciclat de mărimi (granulaţii) grosiere, normale, fine şi foarte fine şi dimensiuni corespunzătoare, fără recuperarea fibrelor de sticlă/de carbon.

Dezavantajul acestor tehnologii şi echipamente este acela că ele rezolvă doar problemele legate de sortare şi mărunţire, la granulaţii diferite, însă nu asigură şi recuperarea de fibre de sticlă şi/sau de carbon. Se asigură astfel doar posibilitatea de reciclare a deşeurilor de materiale compozite şi nu recuperarea şi valorificarea fibrelor de sticlă şi/sau de carbon, de altfel cele mai scumpe din procesul de fabricaţie. Deasemenea sunt cunoscute tehnologii şi echipamente speciale, nemecanice, care asigură extragerea chimică, termică etc. a fibrelor de sticlă şi/sau de carbon din deşeurile de materiale deja sortate şi mărunţite.

Dezavantajele acestor tehnologii şi echipamente sunt acelea că nu se pot recupera fibre de sticlă şi/sau de carbon prin tehnologiile şi echipamentele de sortare şi mărunţire cunoscute, fiind necesare alte tehnologii şi echipamente specifice care induc costuri suplimentare energetice, de materiale, umane etc. Totodată aceste tehnologii şi echipamente sunt neecologice sau necesită costuri importante pentru ecologizarea proceselor respective.

In acest sens, SC ICTCM Institutul de Cercetare si Proiectare Tehnologica prntru Constructii Masini SA Bucuresti, a dezvoltat o tehnologie pentru sortarea şi mărunţirea deşeurilor polimerice compozite şi realizarea unei fracţii de reciclat de înaltă calitate prin recuperarea mecanică a fibrelor de sticlă şi/sau de carbon, destinată reutilizării acestora în procesul de fabricaţie al structurilor din materiale compozite.

Problema tehnică pe care o rezolvă tehnologia este recuperarea mecanică a fibrelor de sticlă şi/sau de carbon odată cu mărunţirea structurilor de materiale

compozite şi sortarea acestora, cu ajutorul unor echipamente speciale de decojire, defibrilare şi recuperare. 2. DESCRIEREA TEHNOLOGIEI

Tehnologia şi echipamentele pentru sortarea şi mărunţirea deşeurilor polimerice compozite şi realizarea unei fracţii de reciclat de înaltă calitate prin recuperarea mecanică a fibrelor de sticlă şi/sau de carbon, conform tehnologiei, înlătură dezavantajele actuale prin aceea că recuperarea fibrelor de sticlă şi/sau de carbon se realizează odată cu mărunţirea deşeurilor de materiale compozite, după sortare şi debitare, în utilaje speciale specifice decojirii, defibrilării şi recuperării propriu-zise a fibrelor de sticlă şi/sau de carbon, precum şi prin obţinerea simultană de fracţii de reciclat de mărimi (granulaţii) grosiere, normale, fine şi foarte fine şi fracţii de fibre de sticlă şi/sau de carbon recuperate.

In figurile urmatoare sunt prezentate cateva scheme logice reprezentative ale procesului de maruntire si reciclare a deseurilor polimerice compozite. Schemele logice sunt inlantuite intr-un ansamblu care reprezinta practic o tehnologie si linie tehnologica pentru sortarea si maruntirea deseurilor polimerice compozite si realizarea unei fractii de reciclat de inalta calitate.

In prima faza deseurile compozite sunt depozitate intr-un container. Daca deseurile vin presortate vor fi depozitate in containere speciale dedicate tipului de deseu presortat. Urmeaza o statie de sortare a materialelor compozite functie de tipul rasinii (figura 1).

Deseurile din materiale termoplaste sunt sortate si depozitate separate intr-un container destinat numai deseurilor termoplaste. Acestea, dupa ce sunt indepartate eventualele insertii metalice sunt duse la topit. Se stie ca deseurile din rasini termoplaste pot fi reciclate prin topire deoarece rasinile termoplaste sunt fuzibile. Se reobtin astfel prin sublimarea rasinii termoplaste valoroasele fibra de stical sau carbon care vor fi reintroduse in procesul de fabricatie al beneficiarului. Materialele composite duroplaste nu mai pot fi retopite. Aceste dupa sortare vor fi depozitate intr-un container separate. Pentru acestea in prima faza are loc o debitare la dimensiuni convenabile 200x 200 mm, astfel incat sa poata fi introduce in instalatiile de maruntire si sortare. Se obtin astfel straifuri de materiale. Spargerea crustei de rasina impregnate pe ambele fete cu reglare la grosimea materialului se realizeaza in utilajul de decojire (figura 2) a structurilor din materiale compozite.


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Figura 1. Statie de sortare

Figura 2. Utilaj de decojire a structurilor Figura 3. Utilaj de defibrilare a structurilor din materiale compozite din materiale compozite

In urma spargerii crustei de rasina va rezulta un

deseu intermediar sub forma unei paturi de fibre cu rasina si a unei fractii de rasina durificata pura care va fi despozitata intr-un recipient special.

Particulele grosiere de rasina precum si particulele fine de rasina si praful rezultat vor fin reintroduse in procesul de fabricatie atat ca umplutura – mai ales in cazul particulelor grosiere –, dar si ca material suport pentru asigurarea unor suprafete lucioase, de inalta calitate a produselor rezultate. Ulterior patura de fibra cu rasina va fi introdusa intr-o

instalatie de defibrilare (figura 3) in care se realizeaza o prima separare a fibrelor printr-un procedeu de indepartare a fibrelor asemanator unui darac.

Practic periile rotitoare ce se afla pe un tambur sau pe doi tamburi printre care trece deseul de material compozit cu fibra de sticla/carbon, vor realiza disocierea fibrelor de rasina, desprinderea lor de pe fibrele de sticla/carbon si eliberarea fibrelor. Reglarea distantei dintre cei doi tamburi functie de grosimea deseului supus procesului de defibrilare


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asigura si evitarea pericolului spargerii/rupei fibrei de sticla/carbon.

Fractia de rasina constituie deseu si va fi depozitata in containerul special pentru rasina macinata. Fibrele obtinute dupa defibrilare nu sunt inca in stare pura.

Pentru a se indeparta si mai mult rasina de pe fibre, deseul intermediar va fi introdus intr-o moara cu valturi, (figura 4) in care are loc maruntirea fibrelor la dimensiuni de 5-8 mm.

Pentru alte dimensiuni utilajul poate fi echipat cu alte tipuri de cutite speciale care pot asigura atat marimea desului maruntit cat si tipul de deseu compozit supus procesului de maruntire.

Figura 4. Utilaj de maruntire - moara cu valturi

pentru maruntit structuri polimerice armate

Deseul de pulbere de rasina rezultat din aceasta instalatie va fi depozitat in containerul pentru rasina. Pentru o separare completa a fibrelor de sticla/carbon din deseurile trecute deja prin procesele de decojire si defibrilare, aceasta ultima fractie va fi introdusa in instalatia finala de recuparare a fibrelor de sticla/carbon (figura 5).

Acest utilaj, specializat, care preia solutia tehnica a unui darac clasic intr-o conceptie moderna, pe baza unui tambur rotativ care preia deseul supus separarii si trece cu acesta prin fata unor piepteni speciali care asigura „scarmanarea” longitudinala a fibrelor pentru a desprinde si ultimele particule de rasina inca impregnate si separarea fibrelor de sticla/carbon aproape pure, fara urma de rasina.

Se asigura totodata si măcinarea tuturor fracţiilor de răşină aspirate de instalaţia de exhaustare şi obţinerea unei pudre de răşină cu granulaţie de ordinul 0,2 mm.

Figura 5. Instalatie de recuperare –

utilaj de macinare CONCLUZII

Tehnologia pentru sortarea şi mărunţirea deşeurilor polimerice compozite şi realizarea unei fracţii de reciclat de înaltă calitate prin recuperarea mecanică a fibrelor de sticlă şi/sau de carbon, permite recuperarea mecanică a fibrelor de sticlă şi/de carbon în utilaje speciale specifice de decojire, defibrilare şi recuperare mecanică propriu-zisă odată cu mărunţirea avansată a deşeurilor de materiale compozite armate cu fibre de sticlă şi/sau de carbon.

Tehnologia si linia tehnologica contine practic patru tehnologii distincte si patru tipuri de utilaje precum si o serie de echipamente, aparatura, sisteme de transfer si manipulare etc. integrate in mod unitar pentru a realiza cinci tipuri de procese: - procesul de sortare pe tipuri de materiale

compozite dar si pentru eliminarea oricaror alte materiale de alta natura;

- procesul de decojire a deseurilor compozite care contin fibre de sticla/carbon prin desprinderea particulelor de rasina;

- procesul de defibrilare a deseurilor compozite care contin fibre de sticla/carbon si trecute prin procesul de decojire, prin desprinderea avansata a particulelor de rasina si obinerea de fibre relativ curate, parte din ele in stare pura;

- procesul de recuperare a fibrelor de sticla/carbon din deseurilor care le contin si care au trecut prin procesele de decojire si defibrilare, in vederea obtinerii de fibre pure de sticla/carbon;

- procesul de maruntire a desurilor compozite care

nu sunt supuse proceselor de decojire, defibrilare


37

si recuperare sau care nu contin fibre de sticla/carbon. Implementarea tehnologiei pentru sortarea si

maruntirea deseurilor polimerice compozite duce la reducerea risipei de energie prin realizarea unei instalatii de reciclarea ecologica a deseurilor din materiale compozite polimerice armate cu fibre de sticla sau fibre de carbon, deseuri ce rezulta din procesul tehnologic al IMM-urilor de profil;

Alte avantaje ale implementarii tehnologiei descrise sunt: - contribuţia la creşterea competitivităţii

economice şi la asigurarea dezvoltării economice durabile;

- creşterea cifrei de afaceri şi a profitului; - dezvoltarea capacităţii tehnologice şi creşterea

productivităţii; - creşterea capacităţii proprii de cercetare-

dezvoltare. - imbunatatirea condiţiilor de muncă, viaţă şi

sănătate prin reducerea noxelor cu peste 80%.

BIBLIOGRAFIE [1]. Teodorescu, F., Avramescu, V., Craciunoiu, S. Stanca, G., “Expansiunea utilizarii materialelor compozite. Noi materiale

compozite, noi aplicatii si noi tendinte ale dezvoltarii in viitor. Aspecte tehnologice. Aspecte privind reciclarea acestora. Abordari actuale si de perspectiva”, Tehnologia Inovativa, Nr. 1, 2006, Bucharest.

[2]. Masina multifunctionala pentru sortarea si maruntirea deseurilor polimerice compozite si realizarea unei fractii de reciclat de inalta calitate, destinata reutilizarii in procesul de fabricatie, contract 267/2008 – program INOVARE.

Quick Info

5th EU Conference: eRenewablia, eHydrogenia, eEficencia 2011, Bucharest, Academia Romana, 20-21 Sept 2011 The yearly European Conference provides a forum for the presentation, discussion, dissemination, generation of new ideas in the fields. The Conference adds scientific contributions in the speeding the accomplishment of successes in above, very important scientific and technical fields. The Conference adds add contributions at the speeding of the implementation of the Hydrogen Economy, Renewable Energy sources / RES & EEB Energy Efficient Buildings, IT & C in Energy Applications. The Conference creates projects, projects proposals and European research consortia. The Conference generates important influences, promotion, at the dissemination, awareness creation, correct information and responses from the stakeholders and end-users, and the creation of the EU Research and Activities Consortia and of EU Projects Proposals BROKERAGE. The papers will be printed in the Conference Preprints Handbook.


38

ACADEMIA ROMÂNĂ

The 5-th TRADITIONAL EUROPEAN & INTERNATIONAL CONFERENCE & EXHIBITION

eRENEWABLIA ©, eHYDROGENIA ©,

eEFFICIENCIA©, 2011 on

RENEWABLE ENERGY, HYDROGEN, ENERGY SAVING, EEB, EEBD, ENERGY EFFICIENCY, IT & C in ENERGY

and THEIRS ECONOMIC / ENVIRONMENT CONSEQUENCES:

September 20-21, 2011, Bucharest, ROMANIA,

http://www.ipa.ro/html/evenimente.html

at: ACADEMIA ROMÂNĂ, AULA MAGNA, calea Victoriei 125


39

TENSILE TEST OF A COMPOSITE MATERIAL USED IN BULIDING OF A MULTIFUNCTIONAL

MACHINE TOOL STRUCTURE

Loredana Păun1, Valeriu Avramescu1, Horaţiu Teodorescu2

1 Mechanical Engineering and Research Institute, Bucharest, ROMANIA, [email protected] 1 Mechanical Engineering and Research Institute, Bucharest, ROMANIA, [email protected]

2 Transilvania University, Brasov, ROMANIA, [email protected]

REZUMAT Lucrarea prezintă o analiză experimentală privind determinarea caracteristicilor la tracţiune, a unui material compozit pultruzionat utilizat in construcţia structurii unei maşini-unelte multifuncţionale CNC, cu scopul de a obţine o greutate cât mai redusă a maşinii.Încercările au fost realizate pe două direcţii datorită anizotropiei materialului: de-a lungul fibrei şi perpendicular pe fibră.În urma analizei se observă ca proprietăţile mecanice determinate de-a lungul fibrei au valori mult mai ridicate decât cele detrminate perpendicular pe direcţia fibrei, ceea ce denotâ o puternică anizotropie a materialului compozit.

ABSTRACT The paper presents an experimental analysies in order to find the tensile characteristic of a pulltruded composite material which is used in building of a CNC multifunctional machine tool structure, in order to get a low weight of the machine. The tensile test was accomplished on two directions becouse of the matreial anizotropy: along and perpendicular to fibre direction.The tensile test shows that the mechanical properties along the fibre direction are much higher than the transverse to the fiber direction, which shows a strong anisotropy of the composite material.

KEYWORDS: machine tools, composite materials, tensile, pulltruded, fibres. CUVINTE CHEIE: masini unelte, materiale compozite, tractiune, pultruzionat, fibre.

1. INTRODUCTION

Technical progress made in the material area is likely to generate a reconsideration of industrial strategies that have been imposed so far in a standardized production system. The significance of the proposed reconsideration is that, for any product, there is definitely a required material, but it creates a competition between different materials, one based on features and its cost, will be chosen for some period of time. In this competition we have seen materials with scientific and practical interest because their evolution is still growing, and the characteristics of these materials can meet the technical and economic conditions of any new product [1].

New materials are defined as synthetic

materials, metal, metallic, organic or inorganic, and combinations of these applications developed specifically for structural or functional characteristics. These materials, usually enter to the consumer market or industry performance because they have satisfying the criteria of mechanical, electrical, chemical and environmental. On this basis, new materials have already acquired a fairly extensive use in construction machinery and technology, aerospace, shipping, rolling stock, electronics and electronics, consumer goods, etc.

Starting from the current stage of researches regarding the utilization of composite materials in various fields, it is proposed an approach to a less development direction, namely the use of composite


40

materials in building of some structure elements which are specific to machine tools [2].

In this way, the Mechanical Engineering and Research Institute has developed a prototype of a multifunctional CNC machine tool for processing by turning, milling, drilling, boring, mortising, toothing and also by plane, cylindrical and helycoidal rectification (fig. 1). In order to get a reduced weight of the multifunctional machine, the frame was made from pultruded composite profiles reinforced with glass fiber which are bounded by metal straps [3].

The objective of this paper is to accomplish an experimental analysis in order to define the resistance characteristics of this pulltruded composite material which is used in the structure building of multifunctional machine tool, after the tensile test.

Figure 1. Multifunctional machine tool

2. MATERIAL AND METHOD

The used material is done by continual reinforced material being pulled through a guide where the fibers are placed precisely in relation to the profile cross section. The fibres are then led through processing equipment where the fibres are impregnated with the matrix material. The combined mixture of fibres and matrix is pulled on through the heated equipment where the profile is cured in its final geometry.

The combination of reinforcemnt in the profile, the type and number of continuous fibres, as well as the type and dimensions of complex weaves and mats are arranged in a way that facilitates visual cheking when the fibres and mats are positioned in a prifile. Precise positioning of fibres and mats are positioned in relation to the cross section of a profile is very important to the properties and qualities of the finished product [4].

The advantages of this pultruded composite material are:

• very fast and economic method to impregnate and cure a polymer matrix composite material,

• the resin content required for impregnation can be controlled very accurate,

• the mechanical properties of the laminates are very good since the profiles present straight unidirectional oriented fibers and high fibers volume fractions can be obtained,

• the impregnation with resin can be accomplished into a closed zone so that volatile emission can be limited.

General properties of composite materials are influenced by the nature and properties of the constituents. In case of fiber reinforced composite materials, the fiber orientation has a strong influence on the material anisotropy. In this respect, the material has been tested along the fibers direction and also transverse to this direction [5].

The tested material is from an I profile. Figure 2 shows the main directions for the material constants stated. 00 indicates the longitudinal direction of the profile. This is also the pulling direction during the pultrusion process, as well as the direction normally used for deflecting beams or columns. The direction which is transverse to the longitudinal direction of the profile is indicated as 900 [4].

Figure 2. Fibres directions – I profile

The material was tensile tested in order to find

its mechanical characteristics. Because of the different characteristics of the material on two directions (along and transverse to fibers direction), the tests have been accomplished on two sets of five samples (fig. 3).

Tensile characteristics of any type of composite material are: - Initial tangent modulus of elasticity and tensile secant modulus; - Maximum tensile stress;


41

- Elongation at maximum force or elongation at break.

Figure 3. Samples cut from I profile

The method consists in applying a progressive

tensile load on the sample longitudinal axis. The test speed is practically the displacing speed

of the fixed clamps to the samples during the machine is working. The speed is chosen so as to ensure a growth speed of the percentage extension rate about 1… 2% per minute. For the tensile test is choosen a speed of 7.5 mm / min for: - Determination of stress; - Determination of elongation; - Determination of tensile modulus of elasticity.

The indivated speed, which is measured during the machine runing, must be maintained to within ± 10%.

The width b is measuring with micrometer, with an accuracy of 0.1 mm and the thickness h with an accuracy of 0.02 mm.

The measurement is made at the sample center and at a distance of 5 mm from each end of the reference length, to its center. Is calculating the arithmetic average of the values found for the width and thickness, which will be used in calculations.

The sample is fixing in the machine clips, ensuring that the longitudinal axis of the sample axis coincides with the axeis of the tested machine. The extensomter is checking and calibrating. If during the clutch in clamp, the sample suffered a tensile effort, the sample is removed before the elongation measurement. The tensile speed is set at 2 mm / min, then is recorded the appropriate elongations and forces.

The main features of the sample are: - sample’s lenght (F): 150±0.5 mm; - width extremities (C): 20±0.5 mm; - sample’s thickness (h): 10±0.5 mm; - length of calibrated tarth (B): 60±0.5 mm; - width of calibrated parth (b): 10±0.5 mm; - reference length (L0): 50±0.5 mm; - distance between clamps (E): 115±5 mm; - distance between coupons (D): 105±5 mm; - length of the coupons (T): 20; - coupons’ thickness (hT): 9±0.5 mm.

Figure 4: Main features of the sample

The samples have been cut according to ISO 527-5:2009 (Plastic – Determination of tensile properties – Part 4: Test conditions for unidirectional fiber-reinforced plastic composites). To avoid the sample degradation during the cutting process, it was used a diamond cutting disc at high speed rotation using a water cooling system.

Figure 5. Detail during the tensile test

3. RESULTS

The followings are the results from the tensile

test, emphasizing the extension depending on load displacement, for the two directions of fibers (fig. 6 and fig. 8). Also, have been determined the Young’s modulus of bending for the two direction of fibers (fig. 7 and fig. 9)

Figure 6. Tensile test – Load – extension distributions

of five samples cut along to fibers direction


42

Figure 7. Tensile test – Load – extension distributions

of five samples cut transverse to fibers direction

0

10000

20000

30000

40000

50000

60000

1 2 3 4 5

Number of samples

You

ng's

Mod

ulus

[MP

a]

Figure 8. Young’s modulus determined along to fibers direction

0

5000

10000

15000

20000

25000

1 2 3 4 5

Number of Samples

Youn

g's

Mod

ulus

Figure 9: Young’s modulus determined transverse

to fibers direction

Were also determined stiffness, maximum bending strain at maximum load and maximum bending stress at maximum extension, both along and perpendicular on fibers direction. In the table 1 are sown the determined characteristics of the material, specifying the maximum and minimum values. Following main features have been also determined: - Stifness: up to 5293500 N/m determinated along to fibres direction and also traverse to fibres direction; - Load at maximum load: up to 16.920 kN determinated along to fibres direction;

- Load at maximum load: up to 2.3696 kN determinated transverse to fibres direction; - Stress at maxiumum load: up to 352.50 MPa determinated along to fibres direction; - Stress at maxiumum load: up to 48.358 MPa determinated transverse to fibres direction; - Extension at maximum load: up to 0.78467 mm determinated along to fibres direction; - Extension at maximum load: up to 0.49996 mm determinated transverse to fibres direction. CONCLUSIONS

The tensile test on samples cut from a profile which is used in building of a machine tool structure, was accomplished along and transverse to the fibers direction.

After analyzing the experimental data is observed as determined mechanical properties along the fiber are much higher than the measured transverse to the fiber, which shows a strong anisotropy of the material.

Also, the test put in evidence some of the main advantages of this kind of composite material: has a good resistance to wear, oxidation and corrosion, is also a good vibration absorber, high value of Young’s modulus has a positive influence on the static and dynamic stiffness of the machine tool structure. Acknowledgement

The work has been funded by the Sectoral Operational Programme Human Resources Development 2007-2013 of the Romanian Ministry of Labour, Family and Social Protection through the Financial Agreement POSDRU/6/1.5/S/19.

The tensile test was accomplished at the Testing Laboratory of Composite Materials from Transilvania University from Brasov.

The samples was cut at the SC COMPOZITE SRL Brasov. REFERENCES

[1]. Alămoreanu, E., Negruţ, C., Calculation of composite

structure, Politehnica University Bucharest, 1993. [2]. Alămoreanu, E., Chiriţă, R., Bars and plates made from

composite materials, Technical Publishing, Bucharest, 1997. [3]. Project Multifunctional CNC machine for processing by

turning, milling, drilling, boreing, mortesing, thoothing and plane, cylindrical exterior and interior and helycoidal rectification – Contract 45/2007 – developed between 2007-2009 within INNOVATION National Program – AMCSIT.

[4]. *** www.fiberline.com [5]. Rosu, D., Goia, I., Teodorescu-D., H., Static and dynamic

behaviour of an extreme rigid and ultra lightweight sandwich structure, The IVth International Conference of Machines dynamic, Brasov, 2005.


43

AN APROXIMATIVE DEFORMATION ANALYSIS WITH FINITE ELEMENT METHOD FOR A DRILLING BAR

Iuliana Iancu

1 Universitatea POLITEHNICA Bucureşti, Romania, [email protected]

REZUMAT Lucrarea de faţă îsi propune analiza stabilităţii unei piese prelucrate prin găurire, folosind metoda elementelor finite. În timpul prelucării asupra piesei acţionează diverse acţiuni (forţe, momente), care vor determina stabilitatea piesei în şi după procesul de prelucrare. Asupra piesei vor acţiona: forţele şi momentele de aşchiere, forţele elastice ale sistemului tehnologic, forţele de strângere ale dispozitivului. Metoda elementelor finite are la bază discretizarea corpului, care în metoda mecanicistă este o sumă a părţilor.

ABSTRACT This paper is propose to analize the stability of a drilling bar , used finite element method.In the cutting process,behind the workpiece actions many forces and moments, which determine the instability in and after the process.In the technical system are the: cutting force, drilling moment,elastic forces of the system stifness of the system,damping forces of the system, fixture forces.Element finite method is based by discretization of the body and in mechanical method a body are the mixt of the many parts.

KEYWORDS: damping system, stiffness system, linear nodal displacements, nodal angular displacements,boundary conditions. CUVINTE CHEIE: amortizarea sistemului, rigiditatea sistemului, deplasările liniare nodale, condiţii limită.

1. INTRODUCTION

Ema and others [1-4] studied the conditions (cutting regime parameters, tools geometry) occured during the drill vibrations. Qiang in [5] presented a diametric deviation calculation model worked by a turning bar. Yang and others [6] developed a method to compensate for the errors.This study involves drilling a processed straight bar, and the known data are: imprecision fixing tool, system stiffness, cutting forces, workpiece geometry. In Figure 1 is presented the bar. 2. STATIC CUTTING MODEL Are known inaccuracies of the tool mounting holes will be send to processing. Due to the forces of drilling, bending subject bar and attachement will enter the bar marked with two clamping forces. The dynamic model requires as input data:equivalent

mass, equivalent damping and equivalent rigidity. For the study the stabilitty of the workpiece we use the element finite method. 2.1. The finite element method From the point of mechanical method the body is considered like a total part sum. It is based on: - the division the body in small parts, named finite element, with geometric simple form, and unknown function at it ist o define for each elements; -we can apply discret method; -choose a model wich respect the geometry of the structure; -the conection of element it is made on nodal points; -the approximate caracter results from really discretization with finite elements geometry; -we need to put the continuity condition in nodal points.


44

For the wording of the method we must have the number of ecuation is equal with the number of unknown variables. The ecuation may be resolve with three methods: -directly, or variational; -residualy; -energy balance. In the figure 1 are observe: -in nodal point 1 are R1 the reaction of the fixture,M1the moment from the fixture,and FS the pressing force; - in nodal point 2are Fa cutting force,Ma drilling force; Fe elasticity force; - in nodal point 3are Fa cutting force,Ma drilling force; Fe elasticity force; -in nodal point 4 are R4 the reaction of the fixture,M1the moment from the fixture,and FS the pressing force. (a)

(b)

(c)

(d)

Figure 1 : (a)Dynamic model ; (b)Theoretical bar actions ;(c) Real bar actions ;(d) Element finite model. But we know that is the teoretical situation, in practice there are so many inaccuracy for example: the inaccuracy of the tools, the inaccuracy of table machine tool, the inaccuracy of the fixture. For the reasom we have all the forces decompose in two components: - one is vertical note Fn normal force - one is tangent note Ft ( in Figure 1.c ) We note α the angle of the tool with Z axis and β the angle of the machine table with axis Z. 2.2 Decompose the forces: Fta,te R1,4 FS Fa,e α R1,4n β Fna,ne FSn R1,4t FSt Fna,ne =Fa,e cosα (1)

Fte,ne= Fa,e sinα (2)

R(1,4)n = R(1,4)cosβ (3)

R(1,4)t =R(1,4) sinβ (4)

FSn= FS cosβ (5)

FSt = FS sinβ (6)

2.3. The static equilibrium =0 (7)

=0 (8)

=0 (9)

Are more possibilities: to make both drill together and each drill separately, first we suppose we can do together and in this condition using the sign rules we can writte:

-2FS cosβ- 2(Fa +Fe)cosα +(R1+R4) cosβ =0 (10)

(R1+R4) sinβ –FS sinβ- 2(Fa +Fe)sinα=0 (11)


45

M1 +(Fa +Fe)(L1+ L2)sinα -( R4-FS) Ltsinβ +2Ma =0

(12)

(FS- R1)Lt sinβ - (Fa+Fe) (L2+2L3)sinα =0 (13)

The clamping force and the elastic force are: FS = (14)

Fe = (15)

Notations: Li the length of the bar elements; E modulus of elasticity; I moment of inertia; D bar diameter; δ global displacements; uiz linear nodal displacement; θiz angular nodal displacement;

resultant forces of nodal i; resultant moments of nodal i;

system moving along the axis; clamping rigidity; fixture rigidity;

K total stiffness rigidity matrix. The basic equation of the finite element method:

K δ = F (16) δ = [u1 θ1 u2 θ2 u3 θ3 u4 θ4 ]T (17) P =[ …]T (18) Writte the resultants of moment and forces in every nodal point : = - FS cosβ+ R1 cosβ (19)

= - Fa cosα+ Fe cosα (20)

= - FS cosβ+ R4 cosβ (21)

= (22)

= = (23)

=0 (24)

Then P became:

P = = (25)

Phan and other in [P1] have shown how to calculate the stiffness matrix for each element ( than we have 3stiffness matrix) in relation

Ki = (26)

For the circular section the moment of inertia is :

I = (27)

Solving equation (16) involves writting constraints:

= (28)

default:

K11 + (29)

(30) Where the is the vector of restricted nodal degrees of fredom and is the vector of free nodal degrees of fredom,P1 vector of unknown nodal actions and P2 vector of known nodal actions. The fixture introduce the constrains :

= =0 (31)

Introduce the (31) in (29) and (30) then we can writte:

(32)

(33)

= (34)


46

= (35)

We are interest for matrix of displacement δ2 , from relations (16), (29) and (30) :

= K22-1 (36)

3.SIMULATION RESULTS AND DISCUSSION 3.1. Input data For analyze by finite method it is necessary to have inportant data : the type of machine tools, the type of tools,the workpiece geometry , tools and workpiece materials. To make a more detalied study we supose we have more cases: two workpiece material, two type of tools, same machine tools. Workpiece material: OLC 45, 10AlCr70 Cutting type: internal and external coolant D= 20 mm d= 8 mm L1= L3=20 mm , L2 = 80 mm E modulus of elasticvity: E= 2, 1.105MPa(OLC45) E= 0,7 .105MPa(10Al Cr 70 ) Calculation of moment of inertie:

- For the workpiece without drill : I1 = π mm4 = 7853 mm4

- For the drills: I2 = π mm4 = 200,96 mm4 And the total moment of inertie is: It = I1 - 2 I2 = 7451,08 mm4

3.2 Cutting force and drilling moment For calculate the cutting force and drilling moment we use coroguide .com

For workpiece OLC 45 Cutting parameters for internal coolant:

Figure 2 : Drill internal coolant

vcMin - vcMax Cutting speed (vc): Spindle speed (n):

80 - 140 99 m/min

3939 rpm

fnMin - fnMax Feed (fn): Feed (vf):

0.15 - 0.34 0.25 mm/r

985 mm/min

Feed force (Ff): 1292 N

Torque (Mc): 5.5 Nm

Where: vc cutting speed fn feed Ff feed force ( Fa) Mc torque (Ma ) From this tabel we observe: =1292 N; = 5,5 N . Cutting parameters for external coolant:

Figure 3 : Drill external coolant

vcMin - vcMax Cutting speed (vc): Spindle speed (n):

80 - 140 99 m/min

3939 rpm



47

0.15 - 0.34 0.25 mm/r

985 mm/min

Feed force (Ff): 1292 N

Torque (Mc): 5.5 Nm

For workpiece10AlCr70

Cutting paramaters for internal coolant: vcMin - vcMax Cutting speed (vc): Spindle speed (n):

80 - 140 62 m/min

2467 rpm


0.15 - 0.34 0.14 mm/r

345 mm/min

Feed force (Ff): 900

N

Torque (Mc): 3.8 Nm

Observation : in case for OLC45 workpiece material the cutting parameters are higher than 10AlCr70, so the displacements will be higher. 3.3. Output data We replace he cutting force and drilling moment in the relation (36), in each material case, for calculate the displacements (linear and angular): u2z =

(37) θ2z =

(38) u3z =

(39) θ3z =

(40) θ4z = (41)

3.4 Flow chart We can make a flow chart for resolve the angular and linear displacement.For this we need the input data which are:

workpiece material, geometry; cutting parameters; tool parameters, material,geometry; reference system.

The most important is to create the finite element model to divide the body in small parts, to choose a model wich respect the geometry of the structure, to include the inaccuracy of machine tools and devices, to put the constrains and the boundary conditions. The output data are : the linear and angular displacements of nodes.

Figure 4 : Flow chart for linear and angular

displacement CONCLUSIONS The most important parameters for fixing device are stiffness and location. The inaccuracy of machine tools in special of tools : geometry can influnce the quality of workpiece. The linear and angular displacements are dependsof:

OUPUT

Reference coordinate system

Static cutting model Dynamic cutting model

Finite element model

Stiffness matrix of elemenets

Total stiffness matrix

Calculate: Fa,Mb

Fixture constrains

coroguide

,

INPUT

Displacements: uiz; θ2z

Workpiece :material, tool Type of cutting Inaccuracy machine tool


48

- tool geometry; - workpiece geometry; - cutting forces and drilling moment.

u2z =

(42) θ2z = (43)

u3z = (44)

θ3z = (45)

θ4z = (46)

REFERENCES [1]. Ema, S., Marui, E., „Theoretical analysion chatter vibration in drilling and its suppresion” ,Journal Material Process Technology 138 (1/3) ( 2003) 572-578. [2]. Ema, S., Fujii,H., Marui, E., „Whirlling vibration in drilling Part 1: cause of vibration and role of chisel edge”, ASME Journal of Engineering for industry 108 (3) (1986) 157-162. [3]. Ema, S., Fujii,H., Marui, E., „Whirlling vibration in drilling Part 2: influence of drill geometry particularity of the drill flank of the initiation of the vivration”, ASME Journal of Engineering for industry 108 (3) (1986) 163-168. [4]. Ema, S., Fujii,H., Marui, E.,”Whirlling vibration in drilling Part 3: vibration analysis in drilling workpiece with a pilot hole” , ASME Journal of Engineering for industry 110 (4) (1988) 315-321. [5]. Qiang, L., Z., Finite element calculation of the deformation of multidiameter workpiece during turning” , Journal of Material Processing Technology 98 (2000) 310-316. [6]. Jianling, G., Rongdi,” A united model of diametral error in slender bar turnning with a follower rest”, International Journal of Machine Tools and Manufacture 46(2006) 1002- 1012. [7]. Phan, V.a., Baron, L., Mayer, J.R.R., Cloutier, G., „Finite element and experimental studies of diametral errors in cantilever bar turning” , Applied Matematical Modelling 27( 2003) 221-232. [8]. www.coroguide.com

Quick Info

YOU CAN 'CREATE THE FUTURE' www.createthefuture2011.com You are invited to enter the 2011 "Create the Future" Design Contest, sponsored by COMSOL, Creo - a PTC product, and Tech Briefs Media Group. The ninth annual contest will recognize outstanding innovations in product design, awarding a Grand Prize of $20,000 USD. New this year is an Electronics Design category sponsored by Digi-Key Corp. Additional entry categories include Consumer Products; Machinery & Equipment; Medical; Safety and Security; Sustainable Technologies; and Transportation. Entries can be submitted by individuals and/or teams in up to seven categories. The top entry in each category will receive a workstation computer from Hewlett-Packard. The top ten most popular entries, as voted on by site registrants, will get a 3D mouse from 3Dconnexion. All qualified entrants will be included in a drawing for NASA Tech Briefs T-shirts, and the winning entries will be featured in a special supplement to NASA Tech Briefs magazine. All entries must be received by June 30, 2011. There is no cost to enter. Visit www.createthefuture2011.com for details and the official entry form.


49

ISSUES CONCERNING THE SMEs ECONOMIC EVOLUTION AND SOCIAL RELATIONS EXPLORED THROUGH

COLLABORATIVE WORKING ENVIRONMENT

Piţurescu Ioan1, Marian Aurel2, Rădulescu Irina3, Onu Ana Maria4, Rotaru Constantin5, Dobrea Cătălin6

1 S.C. ICTCM S.A. Bucharest, ROMANIA, e-mail:[email protected], 2 S.C. AMCAT S.R.L Bucharest, ROMANIA, e-mail: [email protected],

3 S.C. ICTCM S.A. Bucharest, ROMANIA, e-mail:[email protected], 4 INIMM Bucharest, ROMANIA, e-mail: [email protected],

5 INIMM Bucharest, ROMANIA, e-mail: [email protected], 6ASE Bucharest, ROMANIA, e-mail: [email protected]

REZUMAT Lucrarea analizează situaţia IMM-urilor din România, prezintă evoluţia lor economică şi relaţia lor socială, precum şi problemele ivite în desfăşurarea activităţii lor. Deoarece acestea nu beneficiază de mecanismele şi de capacitate de informare, în ceea ce priveşte aspectele esenţiale ale vieţii economice, s-a dezvoltat un instrument util IMM-urilor. Astfel, se propune ideea de Platformă Integrată pentru IMM-uri. Ea va asigura cuplarea vectorilor de interes ai agentilor economici, pe diverse categorii de informatii relationate cu specificul tehnologic şi organizatoric al acestora, cu ofertele, cu ajutorul Mediului Colaborativ de Lucru.

ABSTRACT The paper analyzes the Romanian SMEs situation and it shows their economical development and social relation, also the problems appeared during their activity. Because they don’t have mechanisms and information capacity regarding key aspects of economic life, it has developed an useful tool for SMEs. Thus it is proposed an Integrated Platform for SMEs. It will ensure the interest vestors coupling for the economic agents, on various information categories related to the technological and organizational specifics, connected to the offers, aided by the Collaborative Work Environment.

KEYWORDS: SME, economy, Integrated Platform, Collaborative Working Environment CUVINTE CHEIE: IMM, economie, Platformă Integrată, Mediu Colaborativ de Lucru

1. INTRODUCTION. SMEs POSITION

IN THE ROMANIAN ECONOMIC CONTEXT.

The transition to a market economy begun in 1990 on an exacerbated system crisis, with a state premature withdrawal of the economy, even though it remained a major shareholder in firms, which have been "invited" to privatization. Economic society infrastructure was not ready for this trade, especially in the enterprise culture direction and in the new economy management direction.

During 1993 – 2000 years, the economic structures were transformed into the 'market economy' idea, beginning with state small and medium enterprises systematic privatization and also marking an upward trend in the private SMEs development.

SMEs constitute the most numerous and important firms sample, with their characteristics and functions, but at a reduced scale. Their multitude gives them power and importance, at macro-economic level. Examples to be mentioned are:

- SMEs generate the largest GDP share, in 2007 the percentage is 67.5%;


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- they provide jobs, to over 60% of employed population;

- they constantly generate new jobs, with the highest vitality;

- SMEs generate the most powerful source for the application of innovation in the economy;

- they produce the greatest variety of products, at the lowest possible cost,

- SME is the most flexible company to the production profile changes, which is correlated with market requirements.

These observations should not lead to the conclusion that they underestimate the importance of big enterprises, but national economy guidance and developing directions are different, depending on the branches and fields of national economy, referring to large companies from heavy industry and mining, [1].

In this context we must emphasize the necessity and the existence of a tight horizontal collaboration between SMEs and large enterprises.

Figure 1 presents the increase degree of percentages of SMEs contribution share over national economy GDP.

By analyzing trends for new SME units establishment (Figure 2), it is observed a continuous growing, the chart shows percentages growth rate in comparison to 1995.

The continuous and profound change of the national economy production and selling structure has affected SMEs.

The 2006 data regarding the firms’ number and their size distribution, related to the employees’ number, reveals that the share of companies with up to nine employees (micro enterprises) is overwhelming; these facts has advantages, but also disadvantages.

For 2007 the SMEs number was: - micro SMEs, with 1-9 employees = 508314 firms, - small SMEs, with 10-49 employees = 45 525 firms, - medium enterprises, SMEs with 49-249 employees

= 8881 firms, - large enterprises, firms with over 250 employees = 1636 firms.

It is important to emphasize that 98% of SMEs made a turnover of 2 million EU each, and only 6503 firms made over this amount. Micro SMEs are 92.2% from the firms with less 2 ml. EU turnover.

There are also State-private capital firms and it is revealed the emergence of companies with foreign capital, but their number had decreased. In general, all types of ownership show a decrease, comparing to 2005; an exception are limited societies that had an increase of more than 1.9% , [2].

To know the size, the SMEs activity areas and their share in relation to the SMEs total turnover, in units’ number and percentages, Table 1 shows the SMEs size top 10.

percentages of SMEs contribution share over GDP

020406080

1990

1995

2000

2001

2003

2004

2005

2006

2007

anul

% d

in P

IB GDP percentage

2 per. Mov. Avg.(GDP percentage)

Figure 1. The increase degree of percentages of SMEs contribution share over national economy GDP

new SMEs creation rate compared to 1995

010203040

1996

1998

2000

2002

2004

2006

anul

rata

in %

share percentages

2 per. Mov. Avg.(share percentages )

Figure 2. Trends for new SME units establishment


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Table 1. The SMEs size top 10. ___________________________________________________________________Domain Micro SMEs Small SMEs Medium enterprises CAEN Firms number %Turnover Poz Firms number %Turnover Poz Firms number %Turnover Poz Code __________________________________________________________________________________________ 51 Wholesale and intermediary (without motor) 60073 31,04 1 5230 34,82 1 828 26,56 1 52 Retail (without motor) 145544 19,95 2 6316 11,91 2 447 5,45 5 74 Other service activities 61488 8,11 3 2370 4,47 5 624 2,90 6 45 Constructions 36760 6,73 4 5389 8,33 3 1265 11,65 2 50 Wholesale and retail (auto repair) and fuel 16091 5,99 5 1925 7,20 4 271 7,8 3 60 Land transport and pipelines 26426 4,48 6 1926 3,88 6 329 2,63 9 70 Real Estate 16756 2,54 7 - - - - - - 55 Hotels and Restaurants 23497 2,02 8 - - 15 Food and beverage - - - 2541 3,08 7 599 5,81 4 72 Informatics and others 12831 1,59 10 - - 1 Agriculture,hunting 12004 1,63 9 1152 1,79 10 - 28 Machinery construction Industry and metal products - - 1366 2,18 8 361 2,78 8 63 Transport connected activities, travel agencies - - 438 1,81 9 37 Recyclable waste and scrap materials - - - - 85 2,89 7 25 Metallic construction and metal products 148 2,54 10 ___________________________________________________________________________________________ THE TOTAL AREA AND SIZE 371817 84,13 28743 79,55 4957 71,52 TOTAL SMEs 508314 100 45525 100 8881 100 % of SMEs Total 73.16 63,13 55,81

It the 15 areas listed there are involved more than 72% of the SMEs total number and their turnover value is representing over 78% of the SMEs total turnover; it is an important information in order to limit the area of SMEs economic information analysis vectors on the fields, [1] , [2].

2. SMEs ECONOMIC EVOLUTION

The number of new established firms was 76,083,

in the first half of the 2008 year; it is a 3.5% growth from the same period of precedent year, when 73,446 firms were registered, according to the National Trade Register Office data, at NewsIn request.

Most start-up companies are engaged in wholesale and retail trade and motor vehicles repair (21478 firms). These are followed by construction companies (14252 set up companies) and companies with scientific and technical activities (7893 set up companies).

Fewest new founded companies are in private households’ activities areas, with domestic personnel employers (52), in electricity, gas, steam and air conditioning production and supply (141) and mining (161). Concerning the national distribution, Bucharest holds 12845 set up companies, representing 16.9% share of the total. It is followed by Cluj county, with 4091 firms (5.4%), Constanta county (3144 new set up firms) and Iasi (3095 companies), each having 4.1 % share of the total. Compared to the same period in 2007, the first half of 2008 registered a 2.5% growth of new established Romanian capital companies, while firms with foreign capital and mix one had a 2% and 0 5% decrease.


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There are also mutations concerning the domains and the SMEs turnover that can illustrate by the real estate domain, the recovery of recyclable waste, metal buildings, which reached the top 10 activities in 2006.

About Romanian SMEs participation on international markets it can be seen a low presence and contribution to the European and global economy. However, there must be mentioned the Romanian SMEs with industry participation in international markets, as importers and exporters, the exporters from agriculture domain, the importers represented by hotels and restaurants, transport and communications (5.5% importers, 6.3% exporters and 14.1% subcontractors). Concerning the size category, there is a gap between micro-enterprises and those from small category and medium one. Moreover, micro-businesses in Romania are not trained to seize the economic globalization; they remained oriented mainly towards the goods and services domestic market. It is an obstacles complex standing in front of exporters, the most common reason is the lack of information about foreign markets, while in sectors areas the lack of capital and financing are the main obstacles for transport and communications companies (64.9 %).

SMEs show a balanced optimism about the evolution of their business. Micro-enterprises are much more cautious appreciation of their business than firms in the middle category. Referring to investments in progress, one third of SMEs have no plan to make investment. Among firms that had investment plans, most of them were concerned to acquire technologies and less to invest in environmental protection.

Romanian SME investments are small. Analysis by activities sectors reveals a distinct positive situation in the "Hotels and restaurants" sector and a moderate one in Transport and Communications industries. Analyzing the SMEs size categories, there is a direct correlation between firms’ size and investments size.

Concerning the new products introduction on the market, only one third of SMEs have been able to promote such products. In industry and energy the new products area occupy 38%, in agriculture there are 30%, trade presents 35%, construction, transport and communications reached only 10%. Third of SMEs that have succeeded in the new products market introduction have appealed to three sources: imported new products (45.5%), products developed by other Romanian firms (46%) and products created by own business (40.8%).

New technologies acquisition on the SME sector is low; the most interested companies are in industry and energy, construction trade, transport and communications. Middle class firms have acquired new technology in a 39.6% share, nearly double than the micro SMEs (20.2%), [3].

3. SMEs MANAGEMENT AND SOCIAL RELATIONS

Concerning the quality management system introduction, it remains a major challenge for all SMEs. Thus, agriculture is the weakest, followed by construction, hotels and restaurants. The positive way is given by the industry and energy, trade, services, transport and communications. Actually, none of the sectors are in an advanced position, although analysis shows some differences by sector. There is a direct correlation between company size and capacity to introduce quality systems. SMEs lead at the standard certification category, but there are behind position in environmental management category. Transport and communications category leads by 100%, followed by hotels and restaurants, construction (85%), Commerce, Industry and Energy (75%).

About SMEs attitude towards the business climate, positive developments have been particularly felt by construction companies (33%) and services (31.8%), while transport and communications companies had strong negative developments (28.3% against an average of 18.5%). Medium-sized enterprises (26.6%) assess more than other types of companies that the business environment in Romania has improved.

About regulatory framework, SMEs appreciate the regulations quality of sub-satisfactory and a relatively high level of taxation. Whatever SMEs sector, they are jointed in the assessments about the regulations clarity and new levels of taxation. On matters that require Government support, improved legislation is the leading SME's claims of Executive involvement (68.7% of companies). A large percentage of SMEs (45.1%) believe that their problems are less understood by the Government, [3]. 4. THE FACILITIES OFFERED BY

THE COLLABORATIVE WORKING ENVIRONMENT

Because SMEs are represented by 750,000

economic entities and they make 74% of Romania's Gross Domestic Product (GDP), it is important to assist and to facilitate their activities. Their number increases every year; even the SMEs lifecycle is relatively short, the SMEs annual growth rate is about 12%, in the last 15 years.

Considering the globalization terms, market is highly competitive and the SMEs do not benefit from the mechanisms and information capacity, concerning the essential aspects of economic life: business opportunities, market trends, technological opportunities, the collaborative labor market, legal information, organizational advice.


53

The information space (WEB) offers a data infinity, into a heterogeneous structure; they can cross each SMEs specific interest area. WEB site constitutes an optimal environment for the information transfer for the common interest group (clusters) created by economic entities linked by associated areas, complementary interests and other nearby areal.

Connecting request offers in services area was supported by the creation of Web Service-oriented Computing Environment. Informatics structure is based on Web services standards including W3C language for describing WSDL, UDDI and SOAP on the XML messages structure. An adequate language for semantic descriptions is OWL - Web Ontology Language.

WEB services has led to the definition of Collaborative Working Environment (CWE) s which belong other derivatives concepts. It is developed a special project that will create an Integrated Platform for SMEs. It will provide interest vectors coupling for SMEs economic agents, for various information categories related to their technological and organizational specific and the offers. Those include information concerning the economic, technological, organizational, market categories holded by WEB; the defined area is the Collaborative Working Environment, [4], [5].

It will be created a structure of classes and information types, represented by the special ontological categories oriented on SMEs specific and it will be automatically done by an informatic mechanism for forecast information in real-time for SMEs requirements; it will be connected to a Selections Referentials Collection Library.

The Integrated Platform will achieve: CWE specific functions for SMEs customers: horizontal collaborative or complementary activities, specific services, management support services, management guidance and marketing services, information services and workforce assistance, others, [6].

The most important activities to achieve are: the Selections Referentials Collection Library creation (SRCL), providing SMEs direct assistance related to CWE, ensuring the communication functions with clients.

To CWE automatic exploration and to represent SMEs interest vectors will be developed: ► a taxonomy that will define specific categories of SMEs services and activities, the request customer services and products, actions and events, economic agents definition; ► a semantics relationally based on taxonometrical defined categories that will generate ontological

categories necessary for the Collaborative Working Environment Web exploration.

Information searching mechanism will be presented on five logical levels: the interface level, the logical rules represented by semantics, the database level, the ontological categories level that is represented by the developed taxonomy and semantic.

Selections Referentials Collection Library will be an information depository with its own structure and it will be continuously completed, managed and updated, regardless specific customer requirements; the structure is dynamic and it can be expanded along with the diversifying of customer needs.

Database system sources are: customers data records, statistical data and information obtained from time database processing, SRCL recorded data.

5. CONCLUSIONS

The Collaborative Working Environment will introduce changes and it will have impact in working methods and in the information system, by: - the data collection, analysis and interpretation; - the information and knowledge concerning the decision-making environment, - the recognition of economic criteria and decision alternative; - the economic and mathematical models, specific to the analyzed decision situation; - the different solutions establishment, the adoption and implementation of final solution.

The Collaborative Working Environment will lead to the defining and achieving of a future Integrated Platform to support SMEs, which will have the primary function - the SME operators’ interest vectors coupling, on various information categories, related to the technological and organizational specific, with Web information. REFERENCES [1]. ***. Raportul anual al sectorului IMM din România 2007: Ministerul pentru IMM Comerţ, Turism şi Profesii Libere, 2007, Bucureşti. [2]. ***. Anuarul Statistic al Romaniei 2007 - Institutul Naţional de Statistică, 2007, Bucureşti. [3]. Roşca, Ion, Nicolescu, Ovidiu, Trandafir, Ileana, Isaic-Maniu, Irina, Uscatu, Cristian. O evaluare a adoptării e- business în România din perspectiva interesului IMM-urilor : Revista de Informatică economică nr.4, 2002. ISSN: 1453 – 1305, Bucureşti. [4]. European Commission. New Collaborative Working Environments 2020, Report on industry - led FP7 consultations and 3rd Report of the Experts Group on Collaboration @ Work, February 2006. [5]. European Commission. Collaboration@Work, The 2006 report on new working environments and practices, October 2006. [6]. Dobrican, Ovidiu. An exemple of Collaborative System: International Workshop “Collaborative Support Systems in Business and Education”, 2005. ISBN: 973-651-008-9.


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Quick Info BROKERAGE EVENT VISIO 2011 Event Type: Brokerage Events Start Date: 2-Jun-2011 End Date: 2-Jun-2011 City: Bibao Country: Spain

Description:

The 4th edition of VISIO, one of the largest European Events in the subject of Watch and Intelligence and the main in Spain, will take place in Bilbao from 2nd until 3th of June 2011 at AlhóndigaBilbao. The conference will include Exhibition, Technical seminars and Workshops and Networking activities. Within the framework of these international conference, the Basque Enterprise Europe Network organises the 2nd of June 2011 a brokerage event focused on different areas of watch and intelligence subjects. At the Brokerage Event VISIO 2011, client companies, technicians, advisors, tool developers, knowledge and technology transfer specialists and other professionals will have the opportunity to establish contact, through pre-arranged individual meetings, with the aim of establishing links between business and technological offers and the demands of the users. EC Programmes:

Industrial Sectors:

• INFORMATION TECHNOLOGY

SEAGITAL : the international event on IT for sea

Event Type: Conference/Seminar/Information Day Start Date: 8-Jun-2011 End Date: 9-Jun-2011 City: Le Havre Country: France Description:

SIMULATION : The theme of the first SEAGITAL convention For its first year, SEAGITAL has chosen to explore simulation applications in the maritime sector. Simulation is a common theme shared by all the fields involved the maritime world and is of interest for both the effectiveness and the safety of marine-related trades, with the most advanced digital technologies: 2D and 3D simulation, immersive technology, virtual reality, augmented reality, serious games, etc…. Industrial Sectors: � Transport

� Materials technology � Information processing, information systems � Telecommunications � ENERGY � ENVIRONMENT � Fisheries, resources of the sea

For more information : Name: Lecarpentier First Name: Géraldine Telephone: 00 33 2 32 38 81 49 Fax: 00 33 2 32 38 81 07 Email: [email protected]


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CONSIDERAŢII PRIVIND UTILIZAREA RESURSELOR ENERGETICE REGENERABILE.

STUDIU DE CAZ: SECTORUL ENERGETIC DIN ROMÂNIA

Gheorghe Mihaela1, Rădulescu Alexandru Valentin2, Rădulescu Irina3

1Universitatea POLITEHNICA Bucureşti, Bucureşti , ROMANIA, e-mail: [email protected], 2Universitatea POLITEHNICA Bucureşti, Bucureşti , ROMANIA, e-mail: [email protected],

3 S.C. ICTCM S.A. Bucureşti, Bucureşti , ROMANIA, e-mail: [email protected]

REZUMAT Lucrarea prezintă obiectivele şi principalele direcţii de acţiune ale Politicii Europene privind utilizarea resurselor energetice regenerabile, măsurile întreprinse pentru conservarea energiei şi reducerea emisiei de CO2, precum şi proiectele prioritare şi direcţiile de dezvoltare a sectorului energetic românesc, în acest context. ABSTRACT The paper describes the aims and main strands of EU policy on renewable energy resources use, the measures taken to conserve energy and reduce CO2 emissions, as well as priority projects and directions of development of the Romanian energy sector, in this context. KEYWORDS: renewable energy, energy resources, conservation CUVINTE CHEIE: energie regenerabilă, resurse energetice, conservare

1. UTILIZAREA RESURSELOR

ENERGETICE REGENERABILE CA MIJLOC DE CONSERVARE A ENERGIEI ŞI DE REDUCERE A EMISIEI DE C02

Politica Europeană de utilizare a resurselor energetice regenerabile

Pentru a stopa extinderea surselor energetice

poluante, a răspunde limitărilor impuse de mediu şi a asigura necesarul energetic în viitor, Uniunea Europeană a lansat încă din 1997, documentul strategic "Cartea Albă a Surselor de Energie Regenerabilă", care susţine intensificarea şi extinderea utilizării resurselor regenerabile, pentru energie, [1].

In „Cartea Verde a Siguranţei Alimentării cu energie”(2000), Comisia Europeană relevă faptul că dependenţa faţă de importurile de combustibil şi gaze naturale este în creştere, în corespondenţă cu consumul. Uniunea Europeană importă acum 50% din necesarul său energetic, iar în jurul anului 2030 se prevede o pondere de 70%, datorită creşterii ponderii combustibililor fosili.

Această situaţie face ca Statele Membre să fie vulnerabile din punct de vedere economic, politic şi acţiunea să aibă un impact serios asupra mediului înconjurător. In acelaşi timp trebuie avută în vedere şi contribuţia la reducerea emisiilor de gaze cu efect de seră, [2].

In contextul în care combustibilii fosili convenţionali şi energia nucleară vor continua să aibă un rol principal în producţia de energie, Uniunea Europeană are un program special de acţiune pentru promovarea energiei regenerabile.

Acest program este în deplină concordanţă cu strategia Uniunii Europene pentru dezvoltare durabilă, adoptată în anul 2001, al cărei plan cadru are ca priorităţi: - schimbarea climatică şi utilizarea energiei "curate" (adică a surselor de energie ce nu dăunează mediului); - sănătatea publică; - gestionarea responsabilă a resurselor naturale: - sistemele de transport şi utilizarea terenurilor.

In rezoluţia privind schimbarea climatică (14 februarie 2007), Parlamentul European a punctat faptul că politica energetică reprezintă un element vital al strategiei globale a UE privind schimbările climatice, în care sursele de energie regenerabile şi


56

tehnologiile eficiente din punct de vedere energetic joacă un rol important.

Foaia de parcurs pentru energia regenerabilă prezentată în ianuarie 2007 a stabilit o viziune pe termen lung privind sursele de energie regenerabile în UE. Obiectivele generale obligatorii sunt 20% (cu extindere de până la 25%, prin hotărârile din noiembrie 2008) pentru ponderea energiei regenerabile în cadrul consumului de energie şi minim 10% pentru biocombustibili în transporturi, obiective care trebuie realizate de către fiecare Stat Membru şi pe baza cărora sunt stabilite obiectivele naţionale obligatorii până in 2020, [3].

Există două directive în domeniul energiei regenerabile: pentru electricitate şi pentru biocombustibili. Al treilea sector, încălzirea şi răcirea, nu a fost legiferat până în prezent la nivel european.

Directiva 2001/77/EC (27.09.2001) privind "Promovarea energiei electrice produsă din surse regenerabile pe piaţa unică de energie" stabileşte o cotă orientativă de electricitate de 12% produsă din surse de energie regenerabile, în consumul comunitar total de electricitate până în 2010, [4].

Principalele ei direcţii de acţiune constau în: - creşterea gradului de valorificare a surselor

regenerabile de energie în producţia de energie electrică şi termică;

- stabilirea unei cote-ţintă privind consumul de energie electrică produsă din surse regenerabile de energie, în mod diferenţiat de la o ţară la alta;

- adoptarea de proceduri adecvate pentru finanţarea investiţiilor în sectorul surselor regenerabile de energie;

- simplificarea şi adecvarea procedurilor administrative de implementare a proiectelor de valorificare a surselor regenerabile de energie;

- accesul garantat şi prioritar la reţelele de transport şi distribuţie de energie;

- garantarea originii energiei produse pe bază de surse regenerabile de energie.

Directiva 2003/30/CE (17.05.2003) a Parlamentului European şi a Consiliului de promovare a utilizării biocombustibililor şi a altor combustibili regenerabili pentru transport stabileşte un obiectiv de 5,75% biocombustibili pentru toate tipurile de benzine şi motorine pentru transport plasate pe piaţă până la 31 decembrie 2010, [5].

Concluzia Comisiei, în urma evaluării intermediare, este că obiectivul pentru 2010 nu poate fi realizat - estimările vizează o pondere de aproximativ 4.2%.

Ca urmare a extinderii Uniunii Europene, prin aderarea a noi ţări membre, noul obiectiv strategic, urmărit prin "Cartea Albă a Surselor de Energie Regenerabilă" stabilit conform Documentului SEC (2004) 547 adoptat de Comisia Comunităţii Europene la Bruxelles, in 26.5.2004, este de a majora contribuţia energiei regenerabile, până în anul 2010, de la 12% la 21%.

Tabelul 1. Analiza tehnico - economică a variantelor de dezvoltare a Sistemului Energetic Naţional, [6] Valoarea investiţiilor [mld.Euro] Cheltuieli de exploatare şi întreţinere

[mld.Euro] TOTAL TOTAL

Scen

ariu

l

Pute

rea

nou

inst

alat

a in

20

09-2

035

[MW

]

2009- 2035

2009-2015

2016-2025

2026-2035

2009-2035 2010 2015 2020 2025 2030 2035

SIX 14.423 12,128 5,362 3,207 3,559 51,205 1,729 1,510 1,660 1,749 1,709 1,868

SX 16.523 14,361 7,016 4,107 3,238 47,884 1,649 1,399 1,486 1,579 1,559 1,716

SXI 17.323 15,365 6,435 5,905 3,025 47,541 1,649 1,443 1,474 1,543 1,527 1,685SXII 14.579 15,658 7,532 5,274 2,852 50,419 1,729 1,607 1,621 1,717 1,637 1,803SXIII 14-323 12,217 3,074 6,234 2,909 54,324 1,724 1,534 1,706 1,921 1,813 1,983SXIV 14.539 14,826 3,633 7,998 3,195 54,175 1,724 1,534 1,746 1,836 1,889 2,055SXV 18,139 18,999 7,040 8,235 3,724 51,692 1,649 1,546 1,587 1,756 1,771 1,966SXVI 14.539 14,457 3,701 6,963 3,793 55,002 1,750 1,715 1,755 1,911 1,868 2,013SXVII 18.439 18,471 7,034 7,663 3,774 51,779 1,683 1,546 1,586 1,757 1,809 1,975


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Analiza tehnico - economică a variantelor de dezvoltare a Sistemului Energetic Naţional (SEN) arată că limitările surselor lunare de lignit autohton determină o creştere a investiţiilor cu circa 3% şi o creştere lentă a emisiilor de C02.

Adoptarea tehnologiilor cu zero emisii de C02 conduce la creşterea costului energiei produse cu circa 30%. în scenariile (SXII ÷ SXIV) investiţiile sunt cu (6 ÷ 6,5)% mai mari în scenariul SI. Se consideră că prin aplicarea acestor scenarii va scădea independenţa energetică a României de la circa 80% în prezent la 19% în anul 2035 şi că este necesar să se recurgă la selectarea unui program optim de dezvoltare a SEN ţinând seama de ierarhizarea scenariilor analizate şi să se completeze strategia energetică naţională, astfel încât să se poată conduce la integrarea cu efort minim a SEN în cadrul Sistemului Energetic European.

Din analiza făcută rezultă ca posibilă extinderea puterii SEN cu 14, 539 GW pâna in 2035, in condiţiile utilizării cu prioritate a lignitului din ţară, promovarea cu prioritate a programelor hidroenergetice şi reducerea dependenţei de gazele naturale din import. Acestea vor conduce la costuri cu 7% mai mari faţă de alte variante, dar vor contribui la creşterea siguranţei în alimentarea consumatorilor şi vor înlesni încadrarea SEN în cerinţele Noi Politici Energetice a Uniunii Europene, [6].

2. PROIECTE PRIORITARE ŞI DIRECŢII DE DEZVOLTARE A SECTORULUI ENERGETIC ROMÂNESC

Prezentarea proiectelor prioritare

Proiectele care se vor realiza din fondurile

POSCCE sunt pregătite pentru aplicaţii semnificative bazate pe următoarele, [7]: - Investiţii în instalaţii care favorizează economii

de resurse şi energie electrică (schimbarea resurselor combustibile, instalarea automatelor programabile pentru înregistrarea depăşirilor consumurilor specifice şi proprii tehnologice la nivelul echipamentelor şi aplicarea tehnicii Demand Side Management la nivelul întregului sistem de producţie transport şi distribuţie a energiei).

- Realizarea instalaţiilor de reducere a poluării (desulfurare, arzătoare cu noxe reduse, filtre pentru micşorarea emisiilor nocive etc).

- Modernizarea capacităţilor de producere a energiei prin utilizarea biomasei, a energiei solare, eoliene, geotermale, biocarburanţi şi a altor resurse regenerabile performante.

Cofinanţarea totală asigurată din fonduri structurale pentru domeniile menţionate abordate în intervalul (2009 ÷ 2013) va fi de circa 638 mil.Euro la preţuri curente.

Resursele energetice primare prognozate să acopere cererile de energie transformată pe orizontul 2015, se cifrează astfel: întregul potenţial va atinge în anul 2015 circa 32,67 mil.tep (tonă echivalent petrol), din care:

• cărbune 7,75 mil.tep (lignit 6,25 mil.tep huilă 1,5 mil.tep);

• gaze naturale 8,5 mil.tep; • energie hidro 1,6 mil.tep; • energie nucleară 5,72 mil.tep, • alte surse 4 mil.tep. Proiectele strategice (Nabuco, PEOP-Pan

European Oil Pipeline, proiecte pentru rezolvarea infrastructurii critice) deschid calea spre o colaborare internaţională a sectorului energetic românesc în vederea creşterii performanţelor tehnologico-manageriale a tuturor agenţilor economici din SEN (sectorul resurselor primare, centralele, reţelele electrice şi termice, consumatorii ca surse de consum raţional al energiilor transformate etc).

Proiectul Nabuco urmăreşte conectarea şi valorificarea rezervelor de gaze naturale din perimetrul Mării Negre şi din Orientul Mijlociu cu pieţele europene, prin construirea unor conducte care vor traversa cinci ţări (Turcia, Bulgaria, România, Ungaria şi Austria), în lungime de 3282 km, din care 457 km pe teritoriul ţării noastre, cu termen final de punere în funcţiune în anul 2011. Reţeaua Nabuco va transporta în 2011 circa 8 mld.m³ gaze, cu o extensie până la 25,5 mld.m³ în 2030. Importul de gaze din acesta sursă va fi pentru SEN de (2÷5) 10la9 m³ /an. Acest proiect va stimula competiţia pe piaţa internă de gaze şi pe cea externă, creată de livrările gazelor din Rusia la preţuri nemoderate.

Proiectul PEOP prevede realizarea unei conducte de transport a resurselor petrolifere (sistem de tranzit) între Constanţa şi Trieste (Italia). Prin această conductă se va transporta între (50÷170) 106 tone petrol în anul 2010, cu extensie la 344 mil.tone în anul 2020. Lungimea totală a conductei este de 1360 km din care 649 pe teritoriul României. Piaţa total accesibilă este de 298 mil.t/an. Proiectul este atractiv prin modalităţile comercial viabile şi sigure de transport ţiţei pe distanţe lungi.

Proiectele destinate rezolvării infrastructurii critice a sistemelor distribuite de mari dimensiuni, cu comportament neliniar susceptibil de multiple ameninţări nocive la nivelul resurselor, serviciilor, sisteme informatice, indisponibilităţi datorită avariilor, necontrolat ar avea un impact devastator asupra siguranţei sistemului energetic, cu repercursiuni asupra bunăstării cetăţenilor şi asupra funcţionării normale a autorităţilor statului.


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Studiul infrastructurilor critice reclamă identificarea şi inventarierea vulnerabilităţilor (risc, catastrofe, haos) şi stabilirea măsurilor specifice de protecţie, intervenţie şi recuperare, proiectare şi implementarea unor sisteme informatice performante, cu acţiune preventivă care elimină situaţiile de criză in rezoluţia privind schimbarea climatică (14 februarie 2007), Parlamentul European a anunţat faptul că politica energetică reprezintă un element vital al strategiei globale a UE privind schimbările climatice, în care sursele de energie regenerabile şi tehnologiile eficiente din punct de vedere energetic joacă un rol important.

Uniunea Europeană susţine în continuare utilizarea energiei regenerabile, ţinând seama de faptul că exploatarea acesteia contribuie la încetinirea schimbarilor climatice prin reducerea emisiilor de gaze cu efect de seră, la dezvoltarea durabilă, siguranţă în aprovizionare şi la dezvoltarea unei industrii bazate pe cunoaştere, care să creeze locuri de muncă, să contribuie la creştere economică, competitivitate şi dezvoltare regională.

Foaia de parcurs pentru energia regenerabilă prezentată în ianuarie 2007 a stabilit o moţiune pe termen lung privind sursele de energie regenerabile în Uniunea Europeană.

In prezent se află în dezbatere o nouă Directivă a Parlamentului European şi a Consiliului Uniunii Europene privind promovarea utilizării energiei din surse regenerabile.

Trei sectoare sunt aproape de domeniul energiei regenerabile: electricitatea, încălzirea şi răcirea şi transporturile.

Directivele generale obligatorii sunt de 20% (cu extindere de până la 25% prin hotărârile din noiembrie 2008) pentru ponderea energiei regenerabile în cadrul consumului de energie şi minim pentru biocombustibili în transporturi, ce trebuie realizate de către fiecare Stat Membru, pe seama cărora sunt stabilite obiectivele naţionale obligatorii până în 2020.

Pentru România, pentru care ponderea energiei din surse regenerabile în consumul final de energie era în 2005 de 17,8%, obiectivul privind ponderea energiei din surse de energie regenerabile în consumul final de energie în 2020 este de 24% .

Dezvoltarea unei pieţe pentru sursele şi tehnologiile de energie regenerabilă are de asemenea, un impact pozitiv clar asupra siguranţei în aprovizionarea cu energie, oportunităţilor de dezvoltare regională şi locală, dezvoltării regionale şi rurale, perspectivelor de export şi oportunităţilor de ocupare a forţei de muncă, în special în ceea ce priveşte intreprinderile mici şi mijlocii şi producătorii independenţi de energie.

In această propunere sunt definiţi combustibilii lichizi proveniţi din surse regenerabile în domeniul de utilizare: energie sau transporturi. Astfel au fost introduse definiţiile: • „biolichid" este combustibilul lichid utilizat în

scopuri energetice, produs din biomasa; • „biocombustibil" este combustibilul lichid sau

gazos pentru transport, produs din biomasa. Reducerea emisiilor de gaze cu efect de seră

datorată utilizării biocombustibililor şi a altor biolichide luate în considerare în scopurile energetice se estimează la cel puţin 35 %.

Trebuie evidenţiat că dacă terenul care deţine rezerve mari de carbon în sol este transformat în vederea cultivării materiilor prime pentru biocombustibili şi alte biolichide, o parte a rezervelor de carbon va fi, în general, eliberat în atmosferă, ducând la formarea dioxidului de carbon.

Prin urmare biocombustibilii şi celelalte biolichide nu se pot obţine din materii prime ce provin de pe terenuri cu stocuri mari de carbon, adică de pe terenuri care în 2008 reprezentau: a) zone umede, adică terenuri acoperite sau saturate cu apă în mod permanent sau pentru o perioada semnificativă a anului, inclusiv turbării neexploatate; b) suprafeţe dens împădurite, adică terenuri care acoperă mai mult de 1 hectar, cu copaci mai înalţi de 5 metri şi un coronament de peste 30% sau copaci care pot atinge aceste praguri in situ.

In acelaşi context, biocombustibilii şi celelelte biolichide care sunt luate in considerare in scopuri energetice şi de transport nu se obţin din materii prime ce provin de pe terenuri bogate în biodiversitate, adică de pe terenuri care în ianuarie 2008 sau după această dată deţineau unul din următoarele statute: a) pădure neafectată de activitate umană semnificativă, adică o pădure în care nu a avut loc nici o intervenţie umană semnificativă cunoscută sau unde ultima intervenţie umană semnificativă a avut loc cu suficient de mult timp în urmă, astfel încât structura şi procesele speciilor naturale să se fi putut restabili; b) zone desemnate în scopul protecţiei naturii, exceptând cazul în care se furnizează dovezi conform cărora producţia de materie primă respectivă nu a adus atingere acestui scop. c) păşune bogată în biodiversitate, cu alte cuvinte păşune bogată în specii, nefertilizată şi nedegradată.

Pentru unificarea metodologiilor de evaluare a influenţei asupra mediului se propun reguli pentru calcularea impactului asupra formării gazelor cu efect de seră pentru biocombustibili, alte biolichide şi omologii lor combustibili fosili.


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3. CONCLUZII

Datorită faptului că politica energetică reprezintă un element vital al strategiei globale a Uniunii Europene privind schimbările climatice, este de maximă importanţă să se traseze obiective realiste şi să se ia măsuri corespunzătoare privind sursele de energie regenerabile şi găsirea şi implementarea unor tehnologii eficiente din punct de vedere energetic.

Atât la nivel mondial, cât şi al Uniunii Europene, se pune un accent din ce în ce mai mare pe utilizarea energiei regenerabile, datorită faptului că exploatarea acesteia contribuie la încetinirea schimbarilor climatice prin reducerea emisiilor de gaze cu efect de seră, la dezvoltarea durabilă şi siguranţă în aprovizionare. De asemenea aceasta are un rol deosebit în dezvoltarea unei industrii bazate pe cunoaştere, care să creeze locuri de muncă, să contribuie la creştere economică, competitivitate şi dezvoltare regională.

Pentru România este important atât să îşi respecte obligaţiile asumate privind politica energiei regenerabile, la nivel european, dar să şi participe la proiectele startegice cu alte ţări.

Dezvoltarea unei pieţe pentru sursele şi tehnologiile de energie regenerabilă în ţara noastră are un impact pozitiv clar asupra siguranţei în aprovizionarea cu energie, oportunităţilor de dezvoltare regională şi locală, dezvoltării regionale şi rurale, perspectivelor de export şi oportunităţilor de ocupare a forţei de muncă, în special în ceea ce priveşte intreprinderile mici şi mijlocii şi producătorii independenţi de energie.

BIBLIOGRAFIE

[1]. EUROPEAN COMMISSION. Communication from the Commission. ENERGY FOR THE FUTURE:RENEWABLE SOURCES OF ENERGY.White Paper for a Community Strategyand Action Plan, COM(97)599 final (26/11/1997) [2]. EUROPEAN COMMISSION. Green Paper “Towards a European strategy for the security of energy supply”, COM/2000/0769 final, Nov. 2000 [3]. ***, Strategia de la Lisabona (Consiliul European din 8 şi 9 martie 2007), http://www.europarl.europa.eu/sides/ [4]. European Parliament and Council, Directive of the European Parliament and of the Council on the promotion of electricity produced from renewable energy sources in the internal electricity market. Directive 2001/77/EC – 27 September 2001, Brussels. [5]. European Parliament and Council, The European Strategy on Biofuels, Directive 2003/30 CE, http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L2003:283:0051:0070:EN:PDF [6]. ***, Strategia naţională de dezvoltare energetică a României pe termen mediu 2001– 2004, iunie 2001 [7]. ***, Strategia de dezvoltare energetică a României pe termen lung 2002 – 2015, 2002.

Quick Info

Event Type:

Brokerage Events

Start Date:

14-Sep-2011

End Date:

16-Sep-2011

City: Ankara

Country: Turkey

Description:

"International Electricity Summit/EIF 2011" is a platform in which many different topics concerning electricity generation in Turkey and all around the World will be discussed. The purpose of the congress which will be held with supports of Republic of

Turkey Ministry of Energy and Natural Resources is to evaluate different electricity generation sources multi-faceted and to create an atmosphere in which latest developments and applications could be discussed and handled in every detail.

Throughout this conference, a brokerage event between domestic and foreign companies will be organised with supports of Technology Development Foundation of Turkey; a partner of Europe Enterprise Network- BSN Anatolia Consortium and Republic of Turkey Prime Ministry Investment

Support and Promotion Agency. Congress will be held in Ankara Sheraton Hotel & Convention Center from 14 to 16 September 2011. Representatives of many national and international energy companies and also many academicians,

bureaucrats and representatives of non-governmental organizations will attend to the congress. Main topics to be held in the congress: • Incentives, finance and investments about

renewable energy resources • Problems of electricity generation from natural gas and their solutions • Nuclear energy investment, finance and its applications • Electricity generation, problems of its transmission

and distribution and legal arrangements.

EC Programmes:

Industrial

Sectors:

• ENERGY


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ETNDT5 brokerage event

Event Type: Brokerage Events

Start Date: 19-Sep-2011

End Date: 20-Sep-2011

City: Ioannina

Country: Greece

Description:

Emerging Technologies in Non Destructive Testing (NDT) is an international conference with 16 years of history. It was initiated as a Belgian - Greek conference in Patras and since 1999 the Conference also hosts a technology transfer brokerage event

organised by Praxi/HELP-FORWARD Network. The aim of ETNDT5 is to bring together colleagues from academia and industry in all novel NDT related research areas and applications. The 5th Conference is focusing on NDT and Safety of Civil Engineering

Structures. Topics include among others: - New NDT methodologies and techniques - NDT and Safety of Civil Engineering Structures - NDT for risk based inspection and fitness for service

- NDT and damage tolerance design - On-line inspection - Structural health monitoring - Remote NDT - Smart materials and Structures - NDT applications in naval and aircraft structures

- NDT in Biomedicine and bio-engineering The September 2011 TT Event will take place in parallel to the etech-ndt5 Conference on 19 & 20 September 2011, in Ioannina, Greece.

Target groups. Scientists and entrepreneurs, developers, engineers and practitioners, as well as companies - end users of NDT technologies will be able to review recent developments, identify outstanding needs and solutions for their business.

The Brokerage process. The interested parties will

register and then submit their technology (offer and

request), business and research cooperation profiles, which will be incorporated in the TT Event e-catalogue. The e-catalogue will be distributed to all participants at least a month prior to the Event. Provisional deadlines:

01/06/2011: Technology / Business profile submission 01/07/2011: distribution of e-catalogue 01/08/2011: Expressions of Interest for bilateral meeting collected 01/09/2011: Bilateral meetings timetable

Participants can register (fees) through the conference website: //www.etech-ndt5.uoi.gr/

Industrial Sectors:

• MEASUREMENTS AND STANDARDS

For more information :

Name: KALODIMOU

First Name:

Vassiliki

Telephone: +30 210 3607690

Fax: +30 210 3636109

Email: [email protected]


61


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Revista oferă specialiştilor

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în paginile Revistei.

Instrucţiunile privind redactarea şi trimiterea lucrărilor pot fi obţinute la adresa:

Irina Rădulescu S.C. ICTCM S.A. Bucureşti Şos. Olteniţei nr. 103 Sect. 4 Bucureşti Tel: 021 332 37 70 / 234 Fax: 021 332 07 75 E-mail: [email protected]


SERIE NOUĂ

S. C. ICTCM S. A. Bucureşti şi OID – ICTCM

vă oferă posibilitatea unui abonament pentru 4 numere revistă ⁄ an

la preţul de 60 lei ⁄ an. Pentru detalii şi informaţii suplimentare vă rugăm să luaţi legătura cu:

Irina Rădulescu S.C. ICTCM S.A. Bucureşti Şos. Olteniţei nr. 103 Sect. 4 Bucureşti Tel: 021 332 37 70 / 234 Fax: 021 332 07 75 E-mail: [email protected]

REVISTA CONSTRUCŢIA DE MAŞINI SERIE NOUĂ

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publică revista "Tehnologia Inovativă” – seria nouă a Revistei "Construcţia de maşini", realizează prospecte, cataloage, postere, la comandă,

în condiţii grafice deosebite, cu macheta beneficiarului sau cu design şi machete proprii.

Documents

REVISTA CONSTRUCŢ Ş - ICTCM form TI 1_2011.pdf · maruntirea deseurilor polimerice compozite. realizarea unei fractii de reciclat de inalta calitate, destinata reutilizarii in procesul