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Vol 2 (5) August 2014
International Journal of Students’
Research in Technology & Management
(IJSRTM)
Content
1. Effect of Fiber Length on the Short-Term Flexural Creep Behavior of Polypropylene
C.Subramanian, Abdulrahman Khalfan Hassan Al Mamari and S.Senthilvelan
2. E-Waste: An Emerging Problem of Innovative Society
Rahila N. Gadi and Nabeel Ahmed N.Gadi
3. Trend Analysis of Climate Variability in Salalah, Oman
Mohammed Al-Habsi , Luminda Gunawardhana
and Ghazi Al-Rawas
4. Using a New Programme to Predict Thermal Comfort as a Base to Design Energy Efficient
Buildings
Hanan Al-Khatri and Mohamed B. Gadi
5. Wadi Flow Simulation Using Tank Model in Muscat, Oman
Mohammed Al-Housni, Luminda Gunawardhana and Ghazi Al-Rawas
6. Mobile Ad Hoc Networks
Parth Panchal and Meghana Shroff
International Journal of Students’ Research in Technology & Management
Vol 2 (05), August-September 2014, ISSN 2321-2543, pg 157-162
http://www.giapjournals.org/ijsrtm.html 157
Effect of Fiber Length on the Short-Term
Flexural Creep Behavior of Polypropylene C.Subramanian
*#1, Abdulrahman Khalfan Hassan Al Mamari
#2, S.Senthilvelan
#3
#1 Shinas College of Technology, Oman
#2 Petroleum Development Oman, Oman
#3 Indian Institute of Technology Guwahati, India
Abstract— Injection molded long fiber thermoplastic
components are being used in recent days as a viable replacement
for metals in many applications .Present work focus on the effect
of fiber length on the short-term flexural creep performance of
fiber reinforced thermoplastic polypropylene. Unreinforced
polypropylene, 20 wt % short and 20 wt % long glass fiber
reinforced polypropylene materials was injection-molded into
flexural test specimens. Short-term flexural creep tests were
performed for 2 h duration on molded specimen at various stress
levels with the aid of in-house developed flexural creep fixture.
Experimental creep performance of polypropylene composites
for 2 h is utilized to predict the creep performance with the aid of
four parameter HRZ model and compared with 24 h
experimental creep data. Creep strain was found to be increased
with respect to time for all the test materials and found to be
sensitive with respect to the stress level. Test results also revealed
that long fiber reinforced thermoplastic material possessed
enhanced creep resistance over their counter parts and HRZ
model is sufficient enough to predict creep performance of
polypropylene composites over wide range of stress.
Keywords- Injection molding, flexural creep, thermoplastic,
creep, strain
I. INTRODUCTION
Due to the mass production requirement in the automotive
industries, discontinuous long fiber reinforced thermoplastics
(LFRT) have shown significant role in replacing metals, short
fiber reinforced thermoplastics, thermoset sheet molding and
bulk molding composites [1]. The common problem
associated with unreinforced thermoplastics is creep under
moderate to severe stress at elevated temperature. Creep
resistance of thermoplastic composites is significantly
improved by increase in fiber loadings [2]. Dynamic
mechanical analysis (DMA) was utilized to investigate the
viscoelasticity of injection-molded nylon 6/6 material
reinforced with short and long glass fibers by Sepe[3] and
reported an increase in creep resistance for long glass fiber
reinforced nylon composites. Challa and Progelhof [4]
investigated the effect of temperature on the creep
characteristics of polycarbonate and developed a relationship
based on Arrhenius theory to develop creep master curves.
Pegoretti and Ricco [5] studied the propagation of crack under
creep for varying temperature conditions for polypropylene
composites and observed that speed with which the crack
progresses was dependent on the test temperature.
Krishnaswamy [6] performed extensive creep rupture testing
on high density polyethylene pipes at various hoop stress
levels and temperatures and observed the dependency of
density and crystallinity towards failure. Houshyar [7]
reported the improvement in creep properties with the addition
of long polypropylene fibers in propylene-co-ethylene (PPE)
matrix and visualized the improvement in interfacial
properties. Trans-crystallization of the polypropylene matrix
was observed in the PPE samples due to the thin layer of
matrix on the reinforcement, which was attributed to good
impregnation and wetting of the fibers. Greco et al. [8]
investigated the flexural creep behavior for compression
molded glass fiber reinforced polypropylene at various applied
stress level. The effect of matrix crystallinity was highlighted
for the improvement in creep properties for glass fiber
reinforced polypropylene in their work. Acha et al. [9] studied
the influence of interfacial adhesion in discontinuous jute fiber
reinforced polypropylene. Relation between interfacial
properties and creep deformation were investigated. Higher
creep resistance was observed for polypropylene composites
with good interfacial bonding which was confirmed by the
observation of the composite fractured surfaces.
Findley and Khosla [10] conducted creep tests for
unreinforced thermoplastics; polyethylene, polyvinyl chloride
and polystyrene. Approximation was carried out for the linear
viscoelastic region by power law and compared the creep
performance by estimating the power law coefficient and
power law exponent. Liou and Tseng [11] used Findley power
law to estimate the creep compliance of carbon fiber nylon
composites in hygrothermal condition. Power law model was
modified by Hadid et al. [12] by incorporating the time and
stress dependence during creep loading of polyamide
specimens and estimated four parameters for describing the
deformation occurring in the material and used stress–time
superposition principle to predict long-term material creep
behavior of injection molded fiber glass reinforced polyamide.
International Journal of Students’ Research in Technology & Management
Vol 2 (05), August-September 2014, ISSN 2321-2543, pg 157-162
http://www.giapjournals.org/ijsrtm.html 158
Master curves were developed and a perfect
superposition of the curves at various stress levels was
visualized. Novak [13] used strain energy equivalence theory
and developed a creep predictive model to predict the creep
behavior of talc filled polypropylene. Banik et al. [14]
reported the improvement in creep resistance due to
unidirectional reinforcement for polypropylene-polypropylene
composites. Burger and Findley power law model were used
to predict the short term creep behavior and the underlying
deformation mechanisms were also investigated. Liu et al.
[15] used multi-Kelvin element theory and power law
functions to predict creep compliance in polyethylene material
and compared with the tensile creep experiments.
Even though a lot of works were carried out in the past
pertaining to the experimental creep behavior of plastics and
composites, estimation and prediction of creep data using
mathematical and numerical modeling is limited. Hence in this
work the influence of reinforced fiber length on the creep
performance of thermoplastic composite at various stress
levels at room temperature condition was carried out. The
results obtained through flexural creep test were analyzed
using Findley power law model and empirical model proposed
by Hadid et al [12]. Short term experimental creep results
were used to predict long term creep behavior of the molded
specimen.
II. THEORECTICAL BACKGROUND
A. Findley’s Power Law Model
Mechanical behavior of polymeric material under constant
stress was developed by Findley and Khosla [10]. The general
form of the power law equation is given as
' nt= ε tε(t) (1)
where ε(t) is the time dependent strain,'tε is power law
coefficient which is stress and temperature dependent
coefficient, n is the power law exponent and t is the time after
loading.Power law model is simple in approach and
successfully predicted nonlinear viscoelastic creep behavior of
thermoplastic composites over large range of stress[10-
13]besides
this model is also recommended by American
Society of Civil Engineers (ASCE) for structural plastics
design manual in the analysis of composite materials for long
term structural behavior [16].
B. HRZ Model
Findley’s power law was unsuccessful in accounting for the
stress effect on the mechanical behavior of polymeric
material. The two power law parameters in the Findley-Khosla
model'tε and n are significantly influenced by the applied
stress level. Hadid et al. [12] modified the Findley’s power
law to incorporate time and stress dependence in the model
where the power law coefficient (ε't) and power law exponent
(n) were plotted with respect to stress level (ζ). The best
fitting curve proposed the relation between '
tε and ζ as
( )ζb'ε =at (2)
Similarly the best fitting curve proposed between n and ζ
value takes the form
( )n=c exp e.ζ (3)
Eqs. (2) and (3) are used in eq. (1) and strain at any particular
time (t) can be calculated using the following HRZ equation
cexp(e.ζ)bε(t)= aζ t (4)
where a, b ,c ,e are the curve fitting parameters obtained
from the regression analysis. Chevali et al. [17] used the four
parameter HRZ model to fit the experimental data obtained
from flexural creep investigation for nylon 6/6, polypropylene
and high-density polyethylene based long fiber thermoplastic
composites.
III. EXPERIMENTAL CREEP PERFORMANCE OF
POLYPROPYLENE COMPOSITES
A. Specimen Fabrication
In the current investigation, 20 wt % short glass fiber
reinforced polypropylene (SFPP), 20 wt % long glass fiber
reinforced polypropylene (LFPP) and unreinforced
polypropylene (UFPP) obtained from Saint Gobain were used
for injection molding the specimens. In general, lengths of the
reinforced fibers in the short and long fiber reinforced pellets
are 1 mm and 12.5 mm respectively [18]. Weight average
fiber length of the reinforced fibers after injection molding for
the chosen SFPP and LFPP materials are 0.440 mm and 1.251
mm respectively [19]. The base resin of LFPP and SFPP
materials were having same molecular weight with a melt flow
index of 40 g/10 min. According to the material supplier’s
data, silane type coupling agent has been used for the
manufacturing of SFPP and LFPP materials. Since both the
investigated materials used the same type and amount of
coupling agent, material behavior discussions were limited
only to the reinforced fiber length. Developed injection
molding dies and molded specimens are shown in Figs 1a and
1b. Raw materials were initially preheated for two hours at
353 K and during molding, screw speed of 50 rpm and a low
back pressure of 0.25 MPa were kept to retain the residual
fiber length. Process parameters used for injection molding are
listed in Table I. Due to the presence of reinforced fibers in
LFPP and SFPP materials, temperature in the three zones were
kept higher than unreinforced material.
International Journal of Students’ Research in Technology & Management
Vol 2 (05), August-September 2014, ISSN 2321-2543, pg 157-162
http://www.giapjournals.org/ijsrtm.html 159
Fig 1a .Die for preparing specimens
Fig 1b. Injection molded specimens for flexural creep testing
TABLE 1
INJECTION MOLDING PARAMETERS FOR THE SPECIMENS
Screw diameter 35 mm
L/D 20
Screw speed 50 rpm
Barrel temperature
Zone 1
Zone 2
Zone 3
255 ο C
250 ο C
240 ο C
Injection speed 50 mm/sec
Mold temperature 40 ο C
IV. EXPERIMENTAL METHODOLOGY
A fixture is developed in house to evaluate the creep
performance of molded specimen according to ASTM D2990
standard. The specimen is kept in between the supports as
shown in Fig 2a and the load is applied at the centre of the test
specimen with the means of steel rod attached with dead load.
When the load is applied at the center the specimen is
deflected and the deflection is recorded in the dial gauge as
shown in Fig 2b. Test specimens were loaded with respect to
various stress levels for 2 hrs. Constant load is maintained and
test specimen deflection ( δ(t) ) is continuously measured and
recorded. Creep strain at instantaneous time ( )ε(t) is
computed using the relation (5) [20].
2
6δ(t).dε(t) =
l (5)
where, δ (t) is the deflection at instantaneous time , d is
the thickness and l the test specimen length. The
corresponding stress is calculated using the relation
max3Pl
S =2
2wd
(6)
Where Smax is the stress and P is the load, l is the length
and w is the width and d is the thickness of the specimen .The
length, width and thickness of the specimen is 70mm, 13 and
3mm respectively.
Fig 2(a-b). Assembled view of the flexural creep fixture
V. RESULTS AND DISCUSSIONS
A. Creep Behavior of Polypropylene Thermoplastic
Composites
Creep performance evaluation was carried out at various
loading levels ranging from 18.84 N/mm2 to 47.17 N/mm
2 for
all the materials. Fig 3 shows the 2h creep response of the
chosen test specimens. A raise in creep strain was observed
with the time period for all the specimens. Subsequent to the
preliminary rapid increase in creep strain, the rate of creep
Dial Gauge
Fixture
Steel Rod
Dead Weight
Specimen
Dial gauge
Reading
Fixture
International Journal of Students’ Research in Technology & Management
Vol 2 (05), August-September 2014, ISSN 2321-2543, pg 157-162
http://www.giapjournals.org/ijsrtm.html 160
strain decreases. Three trails were conducted for
calculating creep strain for all the molded materials and the
deviation for LFPP, SFPP and UFPP were found to be 2.5 %,
3.2 % and 1.5 % respectively Improved creep resistance
behavior of long fiber reinforced polypropylene is observed is
due to the improved load transfer from the matrix to the
reinforced fibers and the matrix constriction to deformation.
Chevali et al. [17] also observed a similar behavior with the
increase in loading of glass fiber reinforcement in the nylon
composites.
Fig 3. Comparison of creep strain for three materials for a stress of
22.5N/mm2
Due to the increase in reinforced fiber length, stiffness
retention is more pronounced in LFPP. Due to the substantial
time requirement for the creep investigation, an empirical
model is made use in the subsequent section to predict the
creep strain for a specific period of time.
B. Empirical Model for Predicting Short Term Creep
Behavior
The creep performance of molded specimens was
experimentally investigated for 2h duration for the stress
range varying from 18.84, 22.25, 38.27 and 47.17 N//mm2
and the test results are shown in Fig (4a-4c) .It is vivid from
the results that for all the tested materials, creep strain
increases with time and found to be increased with applied
stress level. Power law function is fitted using eq. (1) for each
and every stress levels thereby power law coefficient ('
tε ),
power law exponent (n) and correlation index (R2) are
determined.
Fig 4b. Creep strain for SFPP
The correlation index, R2 indicates that power law function
provides a good approximation to the visco elastic behavior at
every stress levels. It is vivid from Figs (4a-4c) that the power
law coefficient ('tε ) and power law exponent (n) are
dependent on the stress level and increases with the increase in
stress level
Since the power law coefficient ('tε ) and power law exponent
(n) are sensitive to the stress level, a methodology adopted by
Hadid et al.[12] was used to establish the dependence of
power law coefficient ('tε ) (Fig5a) and power law exponent
(n) (Fig 5b) on applied stress level. Fig 5a shows the best
fitting curve using eq. (2) and depicts the influence of applied
stress (ζ) on power law coefficient ('tε ) for the test specimen .
The constant curve fitting parameters (a, b from eq. 2) are also
shown in Fig 5a. In general the constant parameters a and b
are dependent on glass transition temperature, degree of
crystallinity, and fiber orientation in the composite[20] . These
parameters represent the instantaneous strain normally
visualized during the initial period of load application. Fig 5b
shows the best fitting curve using eq. (3) and elucidates the
influence of applied stress (ζ) on power law exponent (n) for
the test specimen. The constant curve fitting parameters (c, e
from eq. 3) are also shown in Fig 5b. The constant parameters
c and e are dependent on the time period of testing and
relaxation mechanisms involved for the composite. These
parameters represent the viscous response visualized during
the secondary creep process. Eq. (4) is used to predict creep
performance of molded specimen and compared with the 24 h
experimental data as shown in Fig 6 (a-c). It is found that HRZ
model predicted well with the experimental creep performance
of the chosen thermoplastic composite specimen.
International Journal of Students’ Research in Technology & Management
Vol 2 (05), August-September 2014, ISSN 2321-2543, pg 157-162
http://www.giapjournals.org/ijsrtm.html 161
Fig 4c. Creep strain for LFPP
Fig 5a. Variation of power law coefficients over stress
Fig 5b. Variation of power law exponents over stress
Fig 6a Experimental and predicted creep performance of UFPP for 55MPa
Fig 6b Experimental and predicted creep performance of SFPP for 40MPa
Fig 6c Experimental and predicted creep performance of LFPP for 20MPa
International Journal of Students’ Research in Technology & Management
Vol 2 (05), August-September 2014, ISSN 2321-2543, pg 157-162
http://www.giapjournals.org/ijsrtm.html 162
VI. CONCLUSIONS
Discontinuous fiber reinforced polypropylene composites
were injection molded and its short term flexural creep
performance is investigated. Due to the extensive time
requirement for the creep performance evaluation, HRZ model
was used in this work. Creep performance of the molded
specimens was experimentally evaluated for 2 h and short
term creep performance (24 h) was predicted with the aid of
HRZ model over wide range of stress. The predicted
performance was compared with 24 h experimental results and
found to be satisfactory. From the present investigation, HRZ
model was found to be useful in predicting the short-term
creep performance of viscoelastic engineering material.
Experimental results confirmed that long fiber reinforced
thermoplastics possessed enhanced creep retention
characteristic. HRZ model parameters were also utilized to
correlate investigated material characteristics.
REFERENCES
[1] J. Markarian, “Long fibre reinforcement drives
automotive market forward”, Plastics, Additives and
Compounding, Vol.7, pp.24-29, 2005.
[2] B.V. Gupta and J. Lahiri, “Non-linear viscoelastic
behavior of polypropylene and glass reinforced
polypropylene in creep,” Journal of Composite
Materials, Vol.14, pp.288-296, 1980.
[3] Sepe, M.P. Use of advanced characterization
techniques in evaluating the fitness-for-use of long-
glass fiber thermoplastics: San Francisco, 1994,
pp.2029-2032.
[4] S.R .Challa and R.C .Progelhof, “A study of creep
and creep rupture of polycarbonate”, Polymer
Engineering and Science, Vol.6, pp.546-554, 1995.
[5] A. Pegoretti and T.Ricco, “Creep crack growth in a
short glass fibres reinforced polypropylene
composite”, Journal of Material Science, Vol.19,
pp.4637-4641, 2001.
[6] R.K. Krishnaswamy, “Analysis of ductile and brittle
failures from creep rupture testing of high-density
polyethylene (HDPE) pipes”, Polymer, Vol. 28,
pp.11664 -11672, 2005.
[7] S.Houshyar , R.A.Shanks and A. Hodzic, “Tensile
creep behavior of polypropylene fibre reinforced
polypropylene composites”, Polymer Testing,Vol.
24,pp. 257-264,2005.
[8] A.Greco, Claudio Musardo and Alfonso Maffezzoli,
“Flexural creep behaviour of PP matrix woven
composite”, Composites Science and Technology,
Vol.67, pp.1148-1158, 2007.
[9] B.A. Acha M.M.Reboredo, and N.E.Marcovich,
“Creep and dynamic mechanical behavior of PP–jute
composites: Effect of the interfacial adhesion”,
Composites Part A: Applied Science and
Manufacturing, Vol.33, pp.1507-1516, 2007.
[10] W.N. Findley and G. Khosla, “Application of the
superposition principle and theories of mechanical
equation of state, strain, and time hardening to creep
of plastics under changing loads”, Journal of Applied
Physics, Vol.26, pp.821–832,1955.
[11] W.J. Liou and C.I. Tseng, “Creep behavior of nylon-
6 thermoplastic composites”, Polymer Composites,
Vol.18, pp.492-499, 1997.
[12] M.Hadid, S.Rechak and A.Tati, “Long-term bending
creep behavior prediction of injection molded
composite using stress-time correspondence
principle”, Materials Science and Engineering A,
Vol.385, pp.54-58, 2004.
[13] G.E. Novak, “Creep fracture of long fiber reinforced
nylon 66”, Polymer Composites, Vol.16, pp.38-51,
1995.
[14] K.Banik, J.Karger-Kocsis and T. Abraham, “Flexural
creep of all-polypropylene composites: Model
analysis”, Polymer Engineering Science, Vol.48,
pp.941-948, 2008.
[15] H.Liu, M.A.Polak and A.Penlidis, “A practical
approach to modeling time-dependent nonlinear
creep behavior of polyethylene for structural
applications”, Polymer Engineering Science, Vol.48,
pp.159-167, 2008.
[16] American Society of Civil Engineers, Structural
Plastic Design Manual, 1986.
[17] V.S.Chevali, D.R. Dean, and G.M. Janowski,
“Flexural creep behavior of discontinuous
thermoplastic composites: Non-linear viscoelastic
modeling and time–temperature-stress
superposition”, Composites: Part A, Vol. 40, pp. 870-
877, 2009.
[18] “Twintex Product Data Sheet”, Long fiber
thermoplastic pellets, 2005, USA.
[19] C.Subramanian and S.Senthilvelan, “Development
and preliminary performance evaluation of
discontinuous fiber reinforced thermoplastic leaf
spring”, Journal of Materials: Design and
Applications, Proc. of Ins. Mech. E Part L,Vol.
223(3), pp.131-142, 2009.
[20] “ASTM D-2990 Standard test methods for tensile,
compressive, and flexural creep and creep-rupture of
plastics”, ASTM International, Philadelphia.
International Journal of Students‟ Research in Technology & Management
Vol 2 (05), August-September 2014, ISSN 2321-2543, pg 163-167
http://www.giapjournals.org/ijsrtm.html 163
E-Waste: An Emerging Problem of
Innovative Society
Rahila N. Gadi#1
, Nabeel Ahmed N.Gadi*2
#Dept of E&CE-Al-Musanna’s College of Technology, Oman
*Dept of Community Medicine MM institute of Medical Science &Research Mullana, Haryana, India
Abstract– In the past few years there is a revolution in electronic
industry, which increases the volume and varieties of both solid
and hazardous wastes. Urbanization Industrialization, fast
changes in technologies leave a negative impact on health of
human beings. Also increases the pollution in air, land and
water. A growing municipal waste contains hazardous electrical
and electronics products. When dumped in landfill will pollute
the environment badly. This waste is usually named as E-waste
(Electrical an Electronics Waste).In the absence of suitable
techniques and protective measures, recycling e-waste can result
in toxic emissions to the air, water and soil and pose a serious
health and environmental hazard-waste is assuming serious
proportions in developing countries and urgent steps need to be
taken to mitigate this problem. This paper highlights the
problem posed by e-waste and its hazards on environment and
health
Keywords– E-waste (Electrical &Electronic waste), carcinogen,
landfills
I. INTRODUCTION
During the last few years, there is an increasing
acknowledgment of our impact on the environment due to our
lifestyle, while the need to adopt a more sustainable approach
concerning our consumption habits emerges as of particular
significance. This trend regards industrial sector affecting the
consumption habits and especially electronic industry where
the short life cycles and the rapidly developing technology
have led to increased E-waste volume [3]
Electrical and Electronics waste, also known as Electronic
waste or waste electrical & electronics equipment (WEEE), or
in short called E-waste, is used to describe obsolete or end of
life electrical & electronics equipment [4]. There is no
generally accepted definition of E-waste around the
world[2].According to the European Union directive WEEE
means Electrical or Electronic Equipment which is waste
within the meaning of article1(a) of directive75/442/EEC
,including all components, subassemblies and consumables
which are part of the product at the time of discarding
.However E-waste most often misunderstood as comprising
only computers related IT equipment or email spam[5].It is
universally understood as electronic waste disposed of by end
users and a wide range of products, from simple devices to
complex goods .Therefore E-waste comprises both white
goods such as refrigerators ,washing machines and
microwaves ,and brown goods which consists of TV ,Radios
and Computers that have reached their ends for their current
holder[6].
E-waste mainly comes from several sources:
Residue or leftover materials from electronic
products manufacturing process
.Leftover parts or materials or discarded EEE
generated from a repair shop
Obsolete EEE coming from all sector of society like
government offices, Companies, Education institutes,
Household etc
Obsolete electrical or electronic products brought in
by smuggling [7].
The production of electrical & electronic equipment (EEE)
is one of the fastest growing global manufacturing activities.
Rapid economic growth, coupled with urbanization and a
growing demand for consumer goods has greatly increased
both the consumption and the production of EEE [8][9][10]
II. MAGNITUDE OF PROBLEM
The magnitude of the problem is really huge and scary.
According to UNEP, global E-waste generation is growing by
about 40 million tons a year, and predicts that by 2020 in
South Africa & china E-waste from old computers will jump
by 200 to 400% from 2007 levels and by 500% in India
[2].Developing countries are the major dumping grounds for
E-waste. By 2020 there will be increase by 400 to 500%.The
spectrum of hazardous E-waste Mountain looms large
especially for developing countries with serious consequences
for the environment and public health[11].The global E-waste
production is accessed at 20-50 million ton/year, equal to 1-
3% of the estimated global urban waste production. Personal
computers, Cell phones and TV will contribute 5.5 Mt in 2010
and will increase to 9.8Mt in 2015.In developed countries E-
waste will stand for 8% of the urban waste volume[3].Each
International Journal of Students‟ Research in Technology & Management
Vol 2 (05), August-September 2014, ISSN 2321-2543, pg 163-167
http://www.giapjournals.org/ijsrtm.html 164
item‟s participation in the annual E-waste
production(kg/year),depends on each electronics‟ item‟s mass
M(Kg),its quantity (number) in the market and
consumption(N) and its Average life cycle L (year).
Estimated Life E = MN/L
For computers with an average 3 years life cycle
contributes to a greater extent to the total E-waste flow
compared to refrigerators and electric stoves, having an
average of 10-12 years [12].Certain electrical & electronics
equipment‟s which form the major part of the E-waste
generation along with their mass and estimated life cycle are
summarized in Table 1.
TABLE 1
ELECTRICAL & ELECTRONICS EQUIPMENTS & THEIR ESTIMATED
LIFE
Items Mass(Kg) Estimated Life(Yrs)
Personal Computer 25 3
Cell Phones 0.1 2
Television 30 5
Fax Machines 3 5
AC 55 10
Photo copier 60 8
Washing Machine 65 8
Refrigerator 35 10
Microwave 15 7
Vacuum Cleaner 10 10
III. IMPACT ON HEALTH & ENVIRONMENT
E-waste cannot be considered or treated like any kind of
waste, because it contains hazardous and toxic substances
such as heavy metals or others such as dioxins and furans
(produced when E-waste is incinerated).For instance, lead
represent 6% of the total weight of a computer monitor. It is
been reported that nearly 36 chemical elements are
incorporated in electronic equipment‟s [13].Electronic wastes
can cause widespread environmental damage due to the use of
toxic materials in the manufacture of electronics goods.
Hazardous metals such as lead (Pb) ,Mercury(Hg) and
hexavalent chromium[Cr(VI)],in one form or the other are
present in such wastes primarily consisting of cathode ray
tubes(CRTs),PCB, capacitors, mercury switches ,relays
.batteries etc. Liquid Cr tetardants on PCB, LCD, cartridges
from photocopying machines, selenium drums etc. Land
filling of E-waste can lead to the leaching of lead (Pb) into the
groundwater and leads to un-portability of water. If the CRT
is crushed and burned, it emits toxic fumes into the air cause
air pollution, which are very hazardous to human being as
well as animals. A rechargeable battery which contains toxic
substances that can contaminate when burned in incinerators
or disposed of in landfills .E-waste is much more hazardous
than many other municipal wastes. Long term exposure to
these substances damages the nervous system, kidney,
reproductive system, endocrine system and bones. It also
leads to carcinogen (cancer).Workers in E-waste recycling or
disposal sector are poorly protected against the risk of it. They
dismantle E-waste, often by hand in very unhealthy
conditions. The hazardous substances found in the E-waste
are considered dangerous to health. Inhaling or handling such
substances and being in contact with them on a regular basis
can damage the main organs of the human body. Working in
poorly-ventilated enclosed areas without masks and technical
expertise result in exposure to dangerous and slow poisoning
chemicals. Due to lack of awareness, workers are risking their
health [15][14].Scientist who examined Guiyu, China(one of
the popular destinations of E-waste recycling activities) have
determined that because of waste, the location has the highest
level of cancer causing dioxins in the world. Pregnant women
are six times more likely to suffer a miscarriage, and seven
out of ten kids have too much lead (Pb) in their blood [17]. E-
waste is not alone factor in causation of environmental and
health problems but its inadequate management which plays
as a catalyst in the magnitude of the problem.
IV. STRATEGIES FOR REDUCTION OF E- WASTE
The best option for dealing with E-waste is to reduce the
volume. Designers should ensure that the product is built for
re-use and/or upgradability. Stress should be laid on use of
less toxic, easily recoverable and recyclable materials which
can be taken back for refurbishment, remanufacturing,
disassembly and reuse. Recycling and reuse of material are
the next level of potential options to reduce E-waste.
Recovery of metals, plastic, glass and other materials reduces
the magnitude of E-waste. These options have a potential to
conserve the energy and keep the environment free of toxic
materials that would otherwise have been released. It is high
time the manufactures, consumers, regulators, municipal
authorities and policy makers take up the matter seriously so
that the different critical elements are addressed in an
integrated manner. It is need of the hour to have an “E-waste
policy “and national regulatory framework for promotion of
such activities. An E-waste policy is best created but those
who understand the issues. So it is best for industry to initiate
policy formation collectively, but user involvement.
Sustainability of E-waste management system has to be
ensured by improving the effectiveness of collection and
recycling system (e.g: public-private partnership in setting up
buy back or drop off center) and by designing in advance
funding [1][15].The E-waste generated every year globally is
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40-50 million ton out of which 15 to 20 % is
recycled and remaining is dumped in landfills/incinerators. If
we have a good and effective recycling system and good
policies to carry recycling process than we can sustain our
natural resources which is depleting very fast
V. E-WASTE MANAGEMENT
To have a better management of E-waste the end user
should be aware of the hazardous affects of E-waste. Proper
awareness should be given and in turn survey should be
conducted to find what people are doing with their E-waste. Is
they are just dumping in the store room or selling to scrap
people or they are giving back to the company .Find the
amount of E-waste generated, by surveys from all sector of
society, awareness program to educate the people how to
reuse the existing Electrical & Electronics products. Next step
will be the design of a proper E-waste management system to
reduce and to recycle the E-waste generated. The first in the
process is to collect the E-waste from all sector of the society
i.e from companies, institution, residential, hospitals etc.
The second step involved to manage the E-waste is to
apply the principle of three R i.e. Reduce, Reuse and Recycle.
As the duty of the user is that try to minimize the E-waste
generation by up grading the system or repair it. If those
things will not give the expected output then try to resale or
recycle it. Many companies have take back schemes.
Segregation & dismantling of the various equipment or
components is the third step where under proper environment
this process is carried out. In the recycling process we can
recovery many valuable materials and metals. Which can be
reused? The last part is the hazardous materials disposal that
has to be done with at most cares.[1][2][16]
VI.NEED FOR E-WASTE POLICY AND REGULATION
The policy should address all issues ranging from
production and trade to final disposal, including technology
transfer for the recycling of electronics waste. Clear
regulatory instruments, adequate to control both legal or
illegal exports and imports of E-waste and ensuring their
environmentally sound management should be in place.
According to the EU the designers and the manufactures have
to obey the RoHS directive which bans or restrict the use of
certain hazardous substances like lead and its compound,
Cadmium and ,its compound, Mercury, hexavalent chromium,
polybrominated biphenyls[1].The regulations should prohibit
the disposal of E-waste in municipal landfills and encourage
owners and generators of E-waste to properly recycle the
waste. Manufactures of products must be financially,
physically and legally responsible for their products. Better
management of hazardous substances may be implemented
through measures such as
Specific product take back obligations for industry.
Financial responsibility for actions and schemes
Greater attention to the role of new product design.
Follow RoHS directives.
Greater scrutiny of cross border movements of
electrical & electronic products and E-waste
Increasing public awareness by labeling products as
“Environmental Hazard”
Personal protection measures (masks, Gloves,
shields, protective glasses etc) should be made
available to all the workers who are engaged with E-
waste management.
The key questions about the effectiveness of legislation
would includes
What is to be covered by the Term Electronic Waste
Who pays for disposal is the producer responsibility
the answer.
What would be the benefits of voluntary
commitments
How can sufficient recovery of materials be achieved
to guarantee recycling firms a reliable and adequate
flow of secondary materials [18].
A. Benefits of E-Waste
Conservation of natural resources
Preventing soil, water and air contamination by toxic
chemicals.
By back offers for consumers
Creates new jobs in the market
Creates new markets for secondary materials and
components
B. Energy Efficiency [19][16]
Reduction of energy requirement, cost involved in E-
waste recycling is comparatively less than the cost involved in
mining and processing of new materials from scratch.
Recycling of Aluminum can save 95% of energy than
production from basic ore. Recycling of plastic can save 70%
of energy and glass up to 40%.Recovering of metals from
recycling process generates only a fraction amount of co2
emission compared from natural process. Innovation in E-
waste treatment should focus on the major needs to improve
overall sustainability [1][18].Some of the policies in place
globally for effectively managing E-waste are mention in
table 2.
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TABLE 2
REGULATORY MODEL
Producers
Responsibility
Government
Responsibility
Model Commonly known
as EPR
Manufacturers
financially
responsible beyond
point of sale. Take back Schemes &
recycle them up to
a defined
percentage by the
manufacturers
Funding model for
this activity varies
from company to
company
End consumer
taxed a recycling
fee on the
purchased product.
This Tax/Fees is
used to fund the E-
waste collection &
recycling activity
Government is
responsible to
monitor & collect
the E-waste
Current Examples European Union
Japan, South
Korea, Taiwan
Switzerland
California(USA)
Likely Implications Pressure on
manufacturers to
follow RoHS
directive
No incentives for
manufacturer to
create cleaner
design.E-waste not
likely to reduce as
manufacturers do
not have any
liability
VII. CONCLUSION
The Electronic market has revolutionized the whole world
over last decades as Electrical & Electronics products
increasingly capture the major part of our lifestyle. While no
one can give the exact figures how much E-waste is presently
generated or how much of this is hazardous, what is definite is
that if we the people living in the innovative society don‟t try
to manage the E-waste properly then E-waste have the
potential of threatening human health and its environment.
Initiatives are been taken to reduce the volume of generation
and to have an effective recycling techniques, which can
sustain the natural resources as well as conserve the energy.
E-waste in developing countries is a menace. There is lack of
awareness among the people about E-waste. This paper
highlights some of the problems, their impact on human
health and environment, briefly explains how to have an
effective E-waste management system with examples
REFERENCES
[1] Dejo Olowu Article „Menace of E-Wastes in
Developing CountriesAn Agenda for Legal and Policy
Responses‟, Lead Journal-ISS1746-58938/1 Law,
Environment and Development Journal (2012), p.59,
available at http://www.lead-
journal.org/content/12059.pdf
[2] Sustainable Innovation & Technology Transfer
Industrial Sector studies Recycling from E-waste to
resources, July 200 UNEP-STEP
[3] G. Gaidajis*, k. Angelakoglou and d. Aktsoglou, e-
waste: environmental problems and current
management, journal of Engineering science and
technology review 3 (1) (2010) 193- 199
[4] Y. C. Jang and h. Yoon, 2006. The practice and
challenges of electronic waste recycling in korea with
emphasis on extended producer responsibility (EPR).
Anweshaborthaku, pardeepsingh international journal of
environmental sciences volume 3 no.1, 2012
[5] Deepalisinhakhetriwal, philippkraeuchi, rolfwidmer,
2007. Producer responsibility for ewaste management:
key issues for consideration – learning from the swiss
experience.Journal of environmental management,
2007. Xx: 1–1
[6] Shah alam, selangor, electrical and electronic waste
management practice by households in , malaysia,2010,
international journal of environmental sciences volume
1, no 2 ,2010
[7] Ramesh babu b, parandeak, ahmedbasha c. Electrical
and electronic waste: a global environmental problem.
Waste manag res. 2007;25:307–18. [pubmed].
[8] Sinha s. Downside of the digital revolution. Published in
toxics link, 28/12/2007. Accessed 13 feb/96/ec . 2013.
Available: http://www.toxicslink.org/art-
view.php?id=124
[9] V. O. Akinseye, electronic waste components in
developing countries: harmless substances or potential
carcinogen, 2013, annual review & research in biology,
3(3): 131-147 , 2013
[10] Bina rani et al, j advscient res, 2012, 3(1): 17-21 17
[11] K. Betts, producing usable materials from e-waste,
environ sci technol. 42, pp. 6782–6783 (2008)
[12] Musson se, jangnyc, townsendtg, chungih.
Characterization of lead leachability from cathode ray
tubes using the toxicity characteristic leaching
procedure. Environmental science & technology.
2000;34(20):4376-4381
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[13] Ajeetsaojie-waste management: an emerging
environmental and health issue in india,national journal
of medical research,volume 2 issue 1 jan – march 2012
issn 2249 4995
[14] India together: un report spotlights india‟s e-waste pile
up – 31 march 2010. Available from:
http://www.indiatogether.org/2010/mar/env-
unewaste.htm
[15] Electronic waste: where does it go and what happens to
it? By michellecastillo: january 2011. Available from:
http://techland.time.com.
[16] Environment, energy and transportation program;
electronic waste. National conference of state
legislatures [cited june 10, 2006]; available from
http://www.ncsl.org/programs/environ/cleanup/
elecwaste.
[17] Waste wise update: electronics reuse and recycling.
Environmental protection agency 2000 [cited july 14,
2006]; available from: http://
www.epa.gov/wastewise/wrr/updates.htm.
[18] Article on Benefits of E-waste Recycling by Drew
Hendricks in Growing Green Jobs August 6, 2012
Available from www.ewaste.htm
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Trend Analysis of Climate Variability in Salalah,
Oman Mohammed Al-Habsi
#1, Luminda Gunawardhana
#2, Ghazi Al-Rawas
#3
# Department of Civil and Architectural Engineering, Sultan Qaboos University
P.O. Box 33, Postal code 123, Al-Khoud, Sultanate of Oman 1 [email protected]
Abstract—The frequency and intensity of weather events are
expected to change as climate change, which may result in more
frequent and intensive disasters such as flash floods and
persistent droughts. Subsequent impacts will affect regions in
different ways, but projected to worsen conditions in water
scares countries like Oman. In Oman, changes in precipitation
and temperature have already begun to be detected, although a
comprehensive analysis to determine long-term trends has yet to
be conducted. We analyzed daily precipitation and temperature
records in Salalah city of Oman, mainly focusing on extremes. A
set of climate indices, defined in the RClimDex software package,
were derived from the longest available daily series (precipitation
over the period 1943-2011 and temperature over the period 1991-
2011). Results showed significant changes in daily minimum and
maximum temperatures associate with cooling as well as
warming. The annual number of cold nights (percentage of days
when daily minimum temperature (TN) less than 10th percentile
of that during base period: 1991-2000) decreased by 8 days per
decade (p-value = 0.3). On the other hand, the annual number of
warm nights (percentage of days when daily minimum
temperature (TN) larger than 90th percentile of that during base
period) increased by 10 days per decade (p-value = 0.3). In
contrast, the annual occurrence of cold days increased by 11 days
per decade (p-value = 0.25), while the annual occurrence of warm
days decreased by 4 days per decade (p-value = 0.62). The
significant trends apparent in minimum temperatures reveal that
Salalah area has become less cold rather than hotter. Moreover,
contrary trends in minimum and maximum temperatures
indicate that, in long-term, daily temperature range has
decreased in this area.
Annual total precipitation averaged over the period 1943-2011
is 95 mm, which shows a statistically weak negative trend with a -
2 mm/10 yr rate. There is also a tendency for precipitation
extremes according to many indices. The contribution from very
wet days to the annual precipitation totals steadily increases with
significance at 87% level. The positive trend in simple daily
intensity index is also clear and reasonably significant (p-value =
0.29). Results of all these indices lead us to conclude that
precipitation intensity in Salalah has increased while mean
precipitation changes are less marked.
I. INTRODUCTION
Extreme weather events are causing extensive damage to
economy, environment and human life. For example, the
supper cyclone, hurricane gonu in 2007 caused extensive
damage along coastline cities, with total rainfall reached 610
mm near the coast. The cyclone caused about 4 billion in
damage (2007 USD) and 49 deaths (Rafy and Hafez, 2008).
Many studies show that these extreme events that used to be
rare in more than 60 years before are becoming frequent in
many parts of the world in recent decades. Alexander et al.
(2006) assessed changes in daily temperature and precipitation
extremes. They found that the trends in minimum temperature
are more significant, implying that many regions become less
cold rather than hotter. Easterling et al. (2000) revealed the
heavy precipitation change in Siberia and northern Japan
while mean precipitation changes are less marked. Therefore,
greater understanding of occurrence of past extremes is prime
important to avoid or at least to reduce the damages such as
catastrophic floods and prolonged period of droughts
(Beniston et al. 2007; Fowler et al. 2005).
In Oman, changes in precipitation and temperature have
already detected (Al Rawas and Valeo, 2010), although a
comprehensive analysis to determine long-term trends has yet
be conducted. With efforts to build a long-term database, the
Sultan Qaboos University now possessed quality controlled
records of daily temperature over the period 1991-2011 and
daily precipitation over the period 1943-2011. The objective
of this research is to use these data to evaluate the trends of
extreme temperature and precipitation change in Salalah.
II. STUDY AREA
Salalah, the second largest city in the Sultanate of Oman,
located in southern of Oman and on the edge of the Indian
Ocean (Fig. 1). Annual total precipitation averaged over the
period 1943-2011 is 95 mm, which shows statistically weak
negative trend of a 2 mm/10-years. Mean annual temperature
during 1980-2008 warms at a rate of 0.12°C/10-years, which
is relatively small compared to warmings recorded in northern
cities such as Sur and Khasab (1.03 and 0.5°C per decade,
respectively). Salalah costal plain serves one of the intense
agricultural fields in the Sultanate of Oman. Consequently,
over the time, saline water intrusion has become one of the
major issues for the management of sustainable groundwater
resource. By the end of 2003, a main project was operated to
treat wastewater and re-inject 20000 m3 daily in the coastal
wells in Salalah in order to stop seawater intrusion. In past,
severe cyclones have occurred in Salalah area in 1959, 1963
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and 1966. In 2002, a tropical storm affected Salalah
city which brought 58.6 mm rain in the city area and 250.6
mm rain in adjoining mountains.
Fig. 1. Study area in Oman
III. METHODOLOGY
In this study, maximum and minimum temperatures, and
precipitation trends were analysed using a selection of 27
indices. These indices were calculated using RClimDex
software, which was developed by the Expert Team on
Climate Change Detection, Monitoring and Indices
(ETCCDMI) to analyse many aspects of a changing climate
(Alexander et al. 2006). The quality control procedure in
RClimDex was applied to identify errors in data processing.
Both minimum and maximum daily temperatures were
considered as missing values if daily minimum temperature is
greater than daily maximum temperature. Daily maximum and
minimum temperature records were defined as outliers if they
lye outside the range of four standard deviations (STDEV)
from the mean of the records (Mean ± 4 × STDEV). Negative
precipitation records were also considered as missing values.
Homogeneity test was conducted using RHtest software
package to identify abrupt changes in data series. However, no
artificial step changes were detected.
IV. RESULTS AND DISCUSSION
The set of 27 indices used in this study includes 16
temperatures related and 11 precipitation related indices
which describe changes in intensity, frequency and duration of
temperature and precipitation events. For space reason, we
present specific indices with significant impacts, together with
combined indices, if the thresholds represent to values of
hydrological significance. A trend is said to be detected when
a test of the null hypothesis that no trend is present is rejected
at a high significance level, such as 5% or 10%.
We found no significant changes in most of precipitation
indices (Table 1). However, consecutive wet days (CED)
shows negative trend with a confidence 89% (Fig. 2). On the
other hand, consecutive dry days (CDD) increases but exhibits
only a statistically weak relationship with standard error larger
than the slope of the fitted linear regression line. The simple
TABLE I
TEST STATISTICS OF PRECIPITATION INDICES
Index Slope Standard
error P-value
Significant at
5% 10%
CDD 0.253 0.38 0.507 No No
CWD -0.031 0.020 0.113* No No
PRCPTOT -0.194 0.535 0.718 No No
RX1day 0.018 0.211 0.933 No No
RX5day -0.157 0.284 0.581 No Yes
R95P 0.153 0.466 0.744 No No
R95P/
PRCTOT 0.0027 0.0017 0.130* No No
SDII 0.015 0.014 0.285 No No *Significance level < 25%
Fig. 2. Trend of consecutive wet days (CWD)
Fig. 3. Trend of simple daily intensity index (SDII)
Salalah
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Fig. 4. Contribution from very wet days to total precipitation
daily intensity index (SDII), which is the ratio of annual
precipitation and number of wet days, shows a reasonably
positive trend with a confidence of 71% (Fig. 3). Figure 4
depicts that the contribution from very wet days to the annual
precipitation total steady increases with a reasonable high
confidence of 87%. In other words, the probability of the null
hypothesis (no contribution from extreme precipitation)
becomes true is less than 0.13. These results lead us to
conclude that precipitation intensity in Salalah has increased
while the annual total precipitation slightly decreases.
Both absolute temperature indices: TNn (annual minimum
value of daily minimum temperature) and TXx (annual
maximum value of daily maximum temperature) in Table II
exhibit no statistically significant change. However, the trends
of TNx (annual maximum value of daily minimum
temperature, Fig. 5) and TXn (annual minimum value of daily
maximum temperature, Fig. 6) are relatively significant. The
absolute magnitude of the gradients of two curves is higher
than standard errors, even though none of them are
statistically significant at 10% level. The extreme temperature
range (ETR) index calculated from the difference between
TXn and TNx indicates a reasonably strong upward trend (Fig.
7) with a confidence of 86%. In practical point of view, these
changes indicate that the temperature of warmest nights
increases while the temperature of coolest day times decreases.
When the percentile based indices were considered, the annual
number of cold nights (percentage of days when daily
minimum temperature (TN) less than 10th
percentile of that
during base period: 1991-2000) decreased by 8 days per
decade (p-value = 0.3). On the other hand, the annual number
of warm nights (percentage of days when daily minimum
temperature (TN) larger than 90th
percentile of that during
base period) increased by 10 days per decade (p-value = 0.3).
In contrast, the annual occurrence of cold days increased by
11 days per decade (p-value = 0.25), while the annual
occurrence of warm days decreased by 4 days per decade (p-
value = 0.62).
V. CONCLUSIONS
In this study, precipitation and temperature extremes in
Salalah, Oman were investigated using a set of climate indices.
The significant trends apparent in minimum temperatures
reveal that Salalah area has become less cold rather than hotter.
Moreover, contrary trends in minimum and maximum
temperatures indicate that, in long-term, daily temperature
range has decreased in this area.
Many precipitation indices show no statistically significant
trend. However, there is a tendency for precipitation extremes
according to some indices. The contribution from very wet
days to the annual precipitation totals steadily increases with a
confidence of 87%. The positive trend in simple daily
intensity index is also clear and reasonably significant (p-
value = 0.29). However, the annual total precipitation
averaged over the period 1943-2011 shows a weak negative
trend with a -2 mm/10 yr rate. Results of all these indices lead
us to conclude that precipitation intensity in Salalah has
increased while mean precipitation changes are less marked
TABLE III TEST STATISTICS OF TEMPERATURE INDICES
Index Slope Standard
error
P-
value
Significant at
5% 10%
TNn -0.016 0.027 0.562 No No
TXx -0.077 0.105 0.472 No No
TNx 0.024 0.024 0.338 No No
TXn -0.056 0.052 0.299 No No
CSDI -0.353 0.270 0.206* No No
DTR -0.02 0.008 0.025* No No
TN10P -0.217 0.202 0.296 No No
TN90P 0.282 0.266 0.302 No No
TX10P 0.313 0.265 0.253 No No
TX90P -0.120 0.239 0.622 No No
ETR 0.079 0.051 0.137* No No *Significance level < 25%
Fig. 5. Trend of annual maximum value of daily minimum temperature (TNx)
International Journal of Students’ Research in Technology & Management
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Fig. 6. Trend of annual minimum value of daily maximum temperature (TXn)
Fig. 7. Trend of extreme temperature range index (ETR)
ACKNOWLEDGMENT
Authors wishes to acknowledge Prof. Xuebin Zhang and
Prof. Feng Yang at the Climate Research Branch of
Meteorological Service of Canada for providing RClimDex.
REFERENCES
[1] M. E. Rafy, and Y. Hafez, ―Anomalies in meteorological
fields over northern Asia and its impact on Hurricane
Gonu,‖ 28th
Conference on Hurricanes and Tropical
Meteorology, pp. 1–12, 2008.
[2] L. V. Alexander, et al., ―Global observed changes in
daily extremes of temperature and precipitation,‖
Journal of Geophysical Research, 111, D05109,
doi:10.1029/2005JD006290, 2006.
[3] D. R. Easterling, T. R. Karl, K. P. Gallo, D. A. Robinson,
K. E. Trenberth and A. Dai, ―Observed climate
variability and change of relevance to the biosphere,‖
Journal of Geophysical Researches vol. 105, pp. 101–
114, 2000.
[4] G. A. Al-Rawas and C. Valeo, ―Relation between Wadi
drainage characteristics and peak flood flows in arid
northern Oman,‖ Hydrological Sciences Journal,vol. 55,
pp. 377-393, 2010.
[5] M. Beniston et al., ―Future extreme events in European
climate: an exploration of regional climate model
projections,‖ Climatic Change, vol. 81, pp. 71–95, 2007.
[6] H. J. Fowler, M. Ekstrom, C. G. Kilsby and P. D. Jones,
―New estimates of future changes in extreme rainfall
across the UK using regional climate model integrations,
1. Assessment of control climate,‖ Journal of Hydrology,
vol. 300, pp. 212–233, 2005.
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Using a New Programme to Predict Thermal
Comfort as a Base to Design Energy Efficient
Buildings
Hanan Al-Khatri # ¹, Mohamed B. Gadi*²
# Civil and Architectural Engineering Department, Sultan Qaboos University, Oman
* Department of Architecture and Built Environment, University of Nottingham, UK
Abstract---- A strong relationship relates the thermal comfort and
the consumption of energy, especially in the hot arid climate
where the installation of HVAC systems is unavoidable. In fact, it
has been reported that the HVAC systems are responsible for
consuming huge amounts of the total energy used by the
buildings that can globally reach up to 40% of the total primary
energy requirement. The future estimations indicate that the
energy consumption is likely to continue growing in the
developed economies to exceed that of the developed countries in
2020. Under these situations, it seems that the shift towards more
energy efficient buildings is not an option. Because part of any
successful environmental design is to understand the potentials of
the site, the proposed programme (THERCOM) assists in
weighing the indoor and outdoor thermal comfort in different
climates in order to provide better understanding of the site
environment as well as testing the thermal comfort chances of the
initial concepts.
Keywords---- energy efficient buildings, indoor thermal comfort,
outdoor thermal comfort, passive design, arid climate, equatorial
climate, warm temperate climate
I. INTRODUCTION
The current records indicate that the buildings sector is
responsible for consuming 40% approximately of the total
primary energy requirements [1]. For any typical building,
around 80% of this amount is consumed as an operational
energy from which huge amounts are consumed for the
HVAC systems alone [2]. This pattern of consumption is
forecasted to grow as the future estimations predict that in
2020, the energy consumption of the developed economies are
likely to exceed that of the developed countries [1].
The associated negative influences for these consumption
patterns on the ecological systems of the planet impose their
regulation. Hence, the concept of the energy efficient
buildings is an attractive option. The energy efficient
buildings can be characterised by their ability to satisfy both
the proposed design requirements and the operational
demands using the possible minimum energy compared with
other buildings in the same design category [3]. This is mainly
attained via applying the passive environmental design
strategies in addition to utilising the renewable energy
technologies.
In this regard, it may worth mentioning that the thermal
comfort opportunities are defined to a large extent by the
passive design strategies which in turn are mostly defined by
the early design decisions. Thus, it is crucial to analyse and
appreciate the thermal comfort demands in the early stages of
the design in order to satisfy them passively as much as
possible. Under the unavoidable conditions when the HVAC
systems are required to modify the thermal conditions, the
analysis of the thermal demands is still of benefit as it can be
related to control the set points in order to achieve the optimal
efficiency which will be reflected in potential savings.
However, in constructing such buildings, it is crucial to
ensure that the proposed efficiency during the design stages is
reflected in the operational stages as well. In fact, it has been
reported that some of the energy efficient buildings tend to
consume huge amounts of energy in order to keep them
running properly, regardless of the apparent efficiency in the
design stage [3].
The excess consumption of the operational energy may be
partially due to the nature of the method by which the
performance of these buildings is assessed. Frequently, a
simulation approach is implemented to compare the intended
scenario of the energy consumption with an ideal one.
Although the patterns of the occupants' behaviour are often
included, it is difficult to predict the actual patterns.
Therefore, and taking into consideration that most of the
operational energy is consumed to achieve the thermal
comfort, it may be advantageous to view the thermal comfort
demands from the approach of the adaptive models instead of
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applying the analytical ones. The former models are
tailored towards specific groups of people in harmony with
certain types of climates and they intensively consider the
behavioural adaptations patterns [4]. As a result, most likely
their predictions will resemble the actual patterns of
consuming the energy in order to achieve the required thermal
comfort.
Additionally and based on the characteristics of the energy
efficient buildings, it can be understood that, at least in certain
periods of the year, these buildings encompass the concept of
the free running buildings that satisfy the heating and cooling
demands passively. In a comparison with the buildings that
depend on the HVAC systems, the free running buildings
reduce the operational energy by around 50% [5]. However, in
the attempt to use less energy, the risk of achieving poor
quality of the indoor environment is obvious. This situation
can partially be avoided by the comprehensive analysis of
both the buildings thermal demands and the site potentials
which leads to defining the periods at which the buildings can
be operated on the free running mode. Inversely, in the
situations of the uncomfortable conditions, the results of this
analysis can be utilized to define adaptive set points that
achieve the maximum potential savings.
II. THERCOM PROGRAMME
Based on the Visual Basic programming language, the
proposed programme (Thermal Comfort in Different Climates
- THERCOM) has been developed to measure and predict the
thermal comfort in the free running buildings (to download a
trial version of the programme, kindly visit:
http://www.nottingham.ac.uk/~lazmbg/MScREA/). It does so
by means of measuring the wet bulb globe temperature index,
the adaptive model for thermal comfort, and the tropical
summer index. In addition, it assess the thermal comfort in the
outdoor environments by means of measuring the wet bulb
globe temperature index, the wind chill index, the discomfort
index, and the heat index.
THERCOM can measure the thermal comfort in
twelve different cities located in three climates based on the
Koppen-Geiger climate classification. Based on the integrated
data, the predictions can be calculated for 24 hours in each
month for all the integrated indices, except those of the
adaptive model for thermal comfort. This exception was due
to the nature of the integrated formula which is based on the
outdoor monthly mean temperature. The integrated climates
are: the equatorial, arid, and warm temperate climates. The
exclusion of the remaining two climates, i.e. snow and polar,
was due to the relatively low populations in regions where
these climates are dominant [6]. More details about the
programme can be obtained from [7].
By predicting the interior thermal conditions, THERCOM
assists in facilitating the selection of the most optimum design
among the different design alternatives through comparing the
thermal performance [5], [8]. In addition, by defining the
periods at which the interior thermal conditions are
comfortable, the programme in fact defines the periods at
which the HVAC system can be switched off in the examined
building. On the other hand, predicting the outdoor thermal
conditions is crucial in order to design the exterior
environments properly as they affect the indoor environments
[9].
III. METHODOLOGY
The concept of the energy efficient buildings implies the
good matching between the site environment and the used
materials and equipment [3]. Based on this, and for the
purpose of the study at hand, four mock-up models were
constructed with different construction materials for the roof.
The thermal performance of these models was investigated
based on the effectiveness of the roof materials in contributing
towards providing the comfortable thermal conditions.
A. Constructional Details
Despite the construction of the roof, the four models share
identical dimensions, properties, and construction materials of
the other parts of the models. They are basically a 3 m x 3 m x
3 m models with one 40 mm foam core plywood door (1 m x
2.2 m) located at the east facade and a single pane of glass
with aluminium frame window (1.5 m x 1.5 m) located at the
west facade. Brick concrete blocks with total thickness of 340
mm were used for the walls and a 100 mm concrete slab
placed on the ground for the floor. The construction of these
elements is detailed in Table 1.
For the roof, the investigated four construction systems
are:
- Cinder concrete with insulation
- Hardboard slab with insulation
- Timber slab without insulation
- Concrete roof with asphalt cover
The detailed components and their properties are displayed
in Table 2.
The models are assumed to be located in Colombo city. It
has been found that the west wind is dominant according to a
previous analysis study of the city climate.
Therefore, the window was positioned on the west facade
in order to encourage the natural ventilation. The wind
velocity was modified based on the wind power low and based
on Melaragno method to account for the changes in the wind
velocity inside the buildings [10].
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TABLE 1
CONSTRUCTIONAL DETAILS OF THE MODELS ELEMENTS EXCEPT THE ROOF
Layer Width
(mm)
Density
(kg/m³)
Specific
heat
(J/kg.ºC)
Conductivity
(W/m.ºC)
Wall
Brick
Masonry
Medium
110 2000 836.8 0.711
Concrete
Cinder 220 1600 656.9 0.335
Plaster
Building
(Molded Dry)
10 1250 1088 0.431
Floor
Concrete 100 3800 656.9 0.837
Door
Plywood 3 530 1400 0.140
Polystyrene
Foam 34 46 1130 0.008
Plywood 3 530 1400 0.140
Window
Glass
Standard 6 2300 836 1.046
B. Selected Thermal Index
THERCOM programme was used to compute the thermal
comfort for the explored models by means of calculating the
Tropical Summer Index. This model was selected for the
study at hand based on the coincidence of its climatic
boundaries and the climatic conditions of the chosen city [7].
The investigated period includes 288 hours distributed as 24
hours from each month.
IV. RESULTS AND DISCUSSION
A. Periods of Switching-off HVAC
For each model, the dominant thermal conditions over the
examined period are presented in their percentages of thermal
sensation as depicted in Figure 1. As can be noted from the
pie chart of the first model, a comfortable thermal sensation
was dominant in 83% of the investigated hours followed by
slightly warm sensation with a percentage of 16%. In 1% of
the investigated hours, the dominant sensation was slightly
cool.
For the second model, the pie chart indicates that in 78%
of the examined hours, the thermal conditions were
considered as comfortable. In 21% and 1% of the investigated
hours, slightly warm and slightly cool sensations were
presented respectively. For the third model, the thermal
sensation of 76% of the tested hours was comfortable. In the
remaining hours, a slightly cool sensation was present.
TABLE 2
DETAILS OF THE ROOF CONSTRUCTION
Layer Width
(mm)
Density
(kg/m³)
Specific
heat
(J/kg.ºC)
Conductivit
y (W/m.ºC)
Case 1: Cinder concrete with insulation
Aggregate 10 2240 840 1.8
Rubber natural 2 930 2092 0.138
Polystyrene
foam 50 46 1130 0.008
Polyethylene 1 950 2301 0.502
Concrete cinder 100 1600 656.9 0.335
Plaster ceiling
tiles 10 1120 840 0.38
Case 2: Hardboard slab with insulation
Aggregate 10 2240 920 1.3
Rubber
Polyurethane
elastomer
2 1250 1674 0.293
Hardboard slab 10 1000 1680 0.29
Wool, fibrous 10 96 840 0.043
Board 10 160 1890 0.04
Coat 10 2300 1700 1.2
Case 3: Timber slab without insulation
Sand 10 2240 840 1.74
Rubber 2 1100 2092 0.293
Slab 10 300 960 0.055
Plaster Board 10 1250 1088 0.431
Case 4: Concrete roof with asphalt cover
Asphalt cover 6 900 1966 0.088
Concrete
lightweight 150 950 656.9 0.209
Plaster 10 1250 1088 0.431
The fourth model has a different thermal scenario as
demonstrated from the Figure. The comfortable conditions
were dominant in only 52% of the examined hours, with the
slightly warm and warm sensations forming the remaining
percentages as 42% and 6% respectively.
Based on these percentages, it can be concluded that the
longest period in which the mechanical ventilation systems
can be switched off is of the first model followed by the
second, third, and fourth with percentages of 83%, 78%, 76%,
and 52% respectively.
For the rest of the investigated hours, it may be necessary
to use the HVAC systems to achieve the required comfortable
thermal conditions with an obvious need for cooling in the
four cases.
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Fig. 1 Percentages of the thermal sensations of the examined models
A detailed examination of the thermal conditions distributions
as depicted in Figure 2 shows that for the first model, the
mechanical ventilation can be switched off in about 14 hours
from 20 to 10. Although an identical scenario is applicable for
models 2 and 3 as can be noted from the Figure, the scope of
switching off the HVAC systems in the hours from 10 to 20 is
greater for the first model in comparison with the other
models. In the fourth model, the hours at which the HVAC
system can be switched off are limited to around 9 hours in
each of January and February, 6 hours in each of May, June,
November, and December, and the maximum is 13 hours in
each of the months from July to October including both.
Nevertheless, it should not be forgotten that it is possible
to expand the comfortable thermal conditions through the
implementation of the passive design strategies. These
strategies include the proper selection of the materials of the
building envelope, the proper proportion of the openings to
the solid area of the envelope, the orientation, the aspect ratio,
Fig. 2 Hours distribution of thermal sensations of the examined models
Periods of Switching HVAC off
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the integration of the shading devices, etc.
Additionally, it should be mentioned that the use of the fans is
permitted [12] as they consume negligible amount of energy
compared with the HVAC systems to achieve an identical
extension of the comfortable conditions.
B. Selecting the Optimum Roof System
From other perspective, the statistical variance of the
tropical summer index temperatures was calculated for the
four models to show values of 1.92, 2.54, 3.11, and 3.89,
where the means of the index temperatures were 28.59 ºC,
28.69 ºC, 28.91 ºC, and 30.29 ºC in sequence.
The narrowest spread of the index temperatures of the first
model from its mean value, in addition to its longest
comfortable period and consequently shortest uncomfortable
periods especially those with slightly warm conditions in
comparison with other models, indicate that the first model
may be considered as the optimum option within the
investigated alternatives.
Table 3 shows the thermal resistance of the four examined
roofs. It is clear from the table that the first model has the best
thermal performance as it has the highest thermal resistance.
A closer look clarifies that this resistance is mainly due to the
presence of the thick insulation layer (layer 3: Polystyrene
foam) which alone contributes of about 95% of the total roof
resistance.
TABLE 3
DETAILS OF THE ROOF CONSTRUCTION
Resistance of Model 1 Model 2 Model 3 Model 4
Layer 1 0.006 0.008 0.006 0.068
Layer 2 0.014 0.007 0.007 0.718
Layer 3 6.250 0.034 0.182 0.023
Layer 4 0.002 0.233 0.023 -
Layer 5 0.299 0.250 - -
Layer 6 0.026 0.008 - -
Total 6.597 0.532 0.218 0.809
Nonetheless, the relatively good thermal performance of
the first model may additionally be partially due to the
combined effect of the high thermal mass of the concrete deck
in addition to the position of the insulation layer where it was
located above the structural deck close to the outer surface.
This according to [11] is the optimum position for the
insulation to insure the most comfortable thermal conditions
in the hot periods. For the first model, the order of the
construction materials with the insulation closer to the outer
surface insures that most of the heat is being prevented from
passing through conduction to the interior layers of the roof.
The permitted amount is absorbed and stored in the thermal
mass of the concrete and thus delayed from affecting the
interior conditions.
Although a fibrous wool thermal insulation was used in
the second model, its thinness and position towards the inner
side of the roof, in addition to the low thermal mass of the
hard board deck, might contributed towards the lower thermal
performance of this model in comparison with the first model.
Moreover, the lack of the insulation layer had an influence
on the much lower thermal performance of the remaining
models. However, the lower thermal mass of the timber slab
of the third model had a relatively positive impact on the
interior thermal conditions as it has a shorter time lag. This
insures that the indoor temperature follows the exterior
temperature. On the other hand, the high thermal mass of the
concrete deck had contributed in the continuous heat stress
during the night period as it can be noted from Figure 2.
IV. CONCLUSION
Under the current rates of energy consumption, it is
important to consider the occupants' behaviour from the early
stages of design as most of the operational energy is
consumed to achieve the thermal comfort. This consideration
is crucial for the energy efficient buildings as the risk of
having poor quality of indoor environment is possible under
the attempts to reduce the consumption of the operational
energy.
Although calculating the thermal resistance may give an
impression about the thermal performance of the examined
roofs, the effect of the different construction systems and
materials on the actual thermal conditions remains unclear.
Hence, it is important to consult tools such as THERCOM to
understand the predicted thermal comfort experience of the
users by means of computing the thermal comfort indices
suitable for the cases under consideration.
THERCOM is of great importance as it helps in better
understanding and good appreciation of the available thermal
comfort opportunities and the deviation from the required
conditions. This understanding helps in making decisions
about selecting the appropriate equipment, materials,
amenities and possibly adjusting the operating patterns which
eventually will increase the efficiency of the buildings.
In the study at hand, four mock-up models were tested to
explore the thermal performance of the roof construction
system and materials. The thermal comfort conditions were
investigated using the tropical summer index. The aim of this
examination was to define the periods at which the HVAC
systems can be switched off and to select the most optimum
construction system among the explored roofs. The first
model, cinder concrete with insulation, had the optimum
thermal performance. Possible factors incorporated to achieve
this performance include the position of the insulation layer,
its high thermal resistance, and the high thermal mass of the
concrete deck.
Furthermore, and in order to extent the comfortable
conditions of the first model further, it is recommended to
select the construction systems of the other parts of the
building envelope based on their thermal properties, in
particular the thermal mass. However, careful planning of the
buildings layouts should be maintained to ensure the
continuity of the natural ventilation.
International Journal of Students’ Research in Technology & Management
Vol 2 (05), August-September 2014, ISSN 2321-2543, pg 172-177
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Finally, it is recommended to perform further
investigations to explore the extent at which the comfortable
thermal conditions may be extended by means of using fans as
a step before the unavoidable use of the HVAC systems.
REFERENCES
[1] L. Yang, H. Yan, and J. C. Lam, “Thermal comfort and
building energy consumption implications - A review,”
Applied Energy, vol. 115, pp. 164-173, 2014.
[2] M. K. Singh, S. Mahapatra, and S. K. Atreya,
“Adaptive thermal comfort model for different climatic
zones of North-East India,” Applied Energy, vol. 88,
pp. 2420-2428, 2011.
[3] A. Meier, T. Olofsson, and R. Lamberts, “What is an
Energy-Efficient Building?,” in Proc. ENTAC, 2002, p.
3.
[4] R. de Dear and G. S. Brager, “The adaptive model of
thermal comfort and energy conservation in the built
environment,” International Journal of Biometeorolgy,
vol. 45, pp. 100-108, 2001.
[5] M. A. Humphreys, H. B. Rijal, and J. F. Nicol,
“Updating the adaptive relation between climate and
comfort indoors; new insights and an extended
database,” Building and Environment, vol. 63, pp. 40-
55, 2013.
[6] A. K. Mishra and M. Ramgopal, “Field studies on
human thermal comfort - An overview,” Building and
Environment, vol. 64, pp. 94-106, 2013.
[7] H. Al-Khatri and M. B. Gadi, “Development of a new
computer model for predicting thermal comfort in
different climates using Visual Basic programming
language,” in Proc. People and Buildings, 2013, paper
MC2013-P24.
[8] N. Djongyang, R. Tchinda, and D. Njomo, “Thermal
comfort: A review paper,” Renewable and Sustainable
Energy Reviews, vol. 14, pp. 2626-2640, 2010.
[9] L. Shashua-Bar, I. X. Tsiros, and M. Hoffman,
“Passive cooling design options to ameliorate thermal
comfort in urban streets of a Mediterranean climate
(Athens) under hot summer conditions,” Building and
Environment, vol. 57, pp. 110-119, 2012.
[10] F. Allard, Natural ventilation in buildings: a design
handbook, Ed., London, UK: James & James, 1998.
[11] I. C. d'Energia, Ed., Sustainable building: Design
manual, New Delhi, India: The Energy and Resources
Institute, 2004, vol. 2.
[12] F. Nicol and M. Humphreys, “Derivation of the
adaptive equations for thermal comfort in free-running
buildings in European standard EN15251,” Building
and Environment, vol. 45, no. 1, pp. 11 - 17, 2012.
International Journal of Students’ Research in Technology & Management
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Wadi Flow Simulation Using Tank Model
in Muscat, Oman Mohammed Al-Housni
#1, Luminda Gunawardhana
#2, Ghazi Al-Rawas
#3
# Department of Civil and Architectural Engineering, Sultan Qaboos University
P.O. Box 33, Postal code 123, Al-Khoud, Sultanate of Oman
Abstract— In Oman, changes in precipitation intensity and
frequency have already begun to be detected, although the
attributed impacts, such as, flash flooding is poorly understood.
For example, the supper cyclonic storm, hurricane Gonu in 2007
led to the worst natural disaster on record in Oman, with total
rainfall reached 610 mm near the cost. The cyclone and flash
flood caused about $4 billion in damage (2007 USD) and 49
deaths. The objective of this study is to develop a Wadi-flow
simulation model to understand precipitation-river discharge
relationship in Muscat. A lumped-parameter, non-linear,
rainfall-runoff model was used. The Food and Agriculture
Organization (FAO-56) modified Hargreaves equation was used
for estimating reference evapotranspiration (ET0). Precipitation
and temperature data during 1996-2003 were obtained from the
Muscat-airport meteorological station. Observed river
discharges during 26-30, March 1997 were used to calibrate the
model and observations during 1997-2003 were used to verify
our simulations. Simulated water discharges agreed with the
corresponding observations, with the Nash–Sutcliffe model
efficiency coefficient equals to 0.88. This developed model will
later be used with a set of General Circulation Model scenarios
(GCM) to understand the Wadi-flow variations under changing
climate conditions.
I. INTRODUCTION
Oman, located in south-Eastern corner of the Arabian
Peninsula, encompasses a diverse range of topography,
including mountain ranges, low land, coastal areas and arid
deserts. The coastal line of Oman extends over 3165 km and
experiences very severe tropical cyclones. The supper
cyclonic storm, hurricane Gonu in 2007 led to the worst
natural disaster on record in Oman, with total rainfall reached
610 mm near the cost. The cyclone and flash flood caused
about $4 billion in damage (2007 USD) and 49 deaths (Rafy
and Hafez, 2008). Recently changes in intensity and frequency
of the weather events and subsequent impacts demand
countermeasures to adopt with these changes in future.
Hydrological model is an effective tool that could provide
river discharge response attributed to the changes in weather
variables and can be used for planning countermeasures to
cope with the potential impacts.
The tank model developed by Sugawara (1984) is a
lumped parameter, non-linear rainfall- runoff model. The tank
model is composed one, two, three or four tanks laid vertically
in series. Various coefficients represent different hydrological
processes such as surface and subsurface runoff and
infiltration. The different in magnitude of these coefficients in
different catchments reflects the geographical features of the
watersheds. Gunawardhana and Kazama (2012) used the tank
model to study water availability and low-flow analysis of the
Tagliamento River discharge in Italy under changing climate
conditions. Also, this tank model has been used for river
discharge simulations in 12 catchment areas in Japan (Yokoo
et al., 2001). Both studies were done in humid regions, but in
this research, we test the performances of the tank model to
simulate wadi flow in arid region in Oman.
The objective of this study is to develop a Wadi-flow
simulation model to understand precipitation-river discharge
relationship in Muscat (Al-Khoud catchment area). The
developed model is expected to use for climate change
scenarios in future studies to predict wadi flow variations
under changing climate conditions.
II. STUDY AREA
Wadi Al-Khoud in Oman is located in the northern part of
Oman and at the western-north part of Muscat. The
downstream of catchment area is towards northeast Gulf of
Oman (Fig1). The total catchment area approximately is about
1740 km2. The elevation in the catchment area ranges from 41
m at the catchment outlet in Al-Khoud to 2339 m in the inland
mountain area. The climate is arid and it is important for the
water resources, especially for agriculture and domestic
purposes. The annul precipitation occurs in November,
December, March and April as observed from previous data.
The average annual rainfall in Muscat is around 63mm (Al-
Khoud station) to 210 mm (JabalBani Jabir). According to the
meteorological records from 1984 to 2003, the annual average
maximum and minimum temperatures near the catchment
outlet were approximately 33 and 24C°, respectively. The
geology of the catchment area mainly consists of 55% of
igneous and volcanic rocks, whereas, 3% of metamorphic
rocks, 16% of sedimentary rocks and 26% of recent deposits.
III. THEORY
The tank model is a simple non-linear rainfall-runoff
model composed of one or several tanks (Fig. 2). The
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coefficients represented for different hydrological
processes (surface and subsurface runoff and infiltration) are
generally obtained by matching observed and simulated data.
Magnitude differences of these coefficients in different
catchments reflect the geographical features of the watersheds.
The rainfall summed to put into the first tank at the top.
Evapotranspiration is directly subtracted from the top tank.
Among the four tanks in the model, first tank at the top
account for rapid runoff near the ground surface and second
tank models the shallow subsurface runoff process. Other two
tanks at the bottom delayed surplus water from the top two
tanks.
Fig. 1. Study area in Oman
This phenomenon represents hydrological role of the deep
aquifers that accumulate the infiltrating water from the ground
surface and released in to the downstream with certain time
delays (Todini, 2007). Representative mathematical model for
the water exchange between tanks and daily runoff generation
can be expressed as follows.
(1)
(2)
(3)
4
1
,
x
nxn RQ (5)
where
x: number of tanks counted from top
n: number of days from the beginning (1/d)
Δt: length of time step
A(x): runoff coefficient of xth
tank (1/d)
B(x): infiltration coefficient of xth
tank (1/d)
H(x,n): water depth in xth
tank at nth
day (mm)
Z(x): height of runoff hole of xth
tank (mm)
R(x,n): runoff from xth
tank at nth
day (mm/d)
I(x,n): infiltration in xth
tank at nth
day (mm/d)
T(n): total input to first tank at nth
day (mm/d)
Evt(n): evapotranspiration at nth
day (mm/d)
Q(n): total runoff at nth
day (mm/d)
P(n): precipitation at nth
day (mm/d)
Fig. 2. Tank model structure for runoff generation
I(x,n) = B(x)× H(x,n)
T(n) = P(n) – Evt(n)
R(x,n) = A(x)× [H(x,n)-Z(x)] H(x,n) > Z(x)
0 H(x,n) ≤ Z(x)
H(x,n)-[R(x,n)×Δt]-[I(x,n)×Δt]+[T(n+1)×Δt] x=1
H(x,n)-[R(x,n)×Δt]-[I(x,n)×Δt]+[I(x–1, n)×Δt] x≠1
H(x,n+1)=
(4)
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TABLE I
TANK MODEL COEFFICIENTS
* based on 12 catchments in southern Japan from Yokoo et al.
The Food and Agriculture Organization (FAO-56)
modified Hargreaves equation, one of the widely used
temperature based method, was used for estimating reference
evapotranspiration (ET0).
aRTTTT
ET
minmax
minmax0 8.17
2
0023.0
(6)
where Tmax(°C) is the maximum daily air temperature,
Tmin(°C) is the minimum daily air temperature, Ra (MJ/m2/d) is
the extra-terrestrial solar radiation and λ is the latent heat of
vaporization (2.45 MJ/m2/d). Actual evapotranspiration was
estimated by matching observed river discharge with
simulations. Precipitation and temperature data during 1996-
2003 were obtained from the Muscat-airport meteorological
station. The Nash–Sutcliffe model efficiency coefficient is
used to assess the predictive power of hydrological models. It
is defined as:
T
t
t
m
t
o
T
t
t
m
t
o
E
1
2
1
2
1
where Qo is observed discharge, and Qm is modelled
discharge. Qot is observed discharge at time t. The closer the
model efficiency is to 1, the more accurate the model is. If the
simulated discharges obtained from the tank model and
historical discharges have a trend and significant correlations,
the simulation is considered successful and the tank model can
be used to evaluate the flow phenomena for the concerning
watersheds.
IV. RESULTS AND DISCUSSIONS
Model calibration was done by matching observed river
discharges at gage station at the outlet of the catchment area in
1997 and the model verification was done according to data
observed in 1997, 1999, 2000 and 2003 (Fig.3). Simulated
wadi flow agreed with the corresponding observations, with
Nash-Sutcliffe model efficiency coefficient of 0.88. Table 1
shows the calibrated model parameters in Al-Khoud
catchment area. These model parameters in Al-Khoud were
compared with the derived parameters in 12 catchment areas
in Japan for understanding parameter dependency on different
geographical and climatic settings.
The coefficients of the tank model represent different
hydrological processes of the catchment. As example, larger
A1 coefficient produces higher rapid surface runoff near the
ground surface, while larger B1 coefficient stands for higher
infiltration capacity. According to Table 1, A11 coefficient in
Al-Khoud catchments is smaller than that in Japanese
catchments. This is because top soil layer in Oman catchments
generally has very low soil moisture content due to extreme
dry condition in air and high evaporation throughout the year.
Therefore, infiltration potential is higher and runoff potential
in very shallow subsurface layer is low in catchments in Oman
than them in Japan. For this reason, Al-Khoud catchments
generate smaller A11 coefficients for the tank models than in
Japanese catchments. In contrast, A12 coefficient for Al-
Khoud catchment area is greater than Japanese catchment
area. This can be attributed to the high representative gradient
(RG) of the catchments in Oman than in Japan. Steep slope in
Al-Khoud catchment area increases the runoff potential in the
shallow subsurface layers. Therefore, infiltrated water from
the top soil surface rapidly flows to downstream areas rather
than recharging deep aquifers. For the same reason, Al-Khoud
catchment area has small storage capacities (Z11, Z12 and Z2)
than the Japanese catchments. Moreover the land-use types in
the catchment area have a significant effect in retaining water
in shallow subsurface layers. Absence of full grown trees with
deep spread roots in Oman facilitates rapid subsurface flow
which attenuates groundwater recharge and subsurface
storage. This phenomenon replicate with small Z coefficients
in Oman than in Japan. B1 coefficients between two
catchments also depict significant differences. These
variations indicate that the Al-Khoud catchment has higher
infiltration capacity than the Japanese catchments, which may
also be attributed to the low soil moisture content in Al-Khoud
than in Japanese catchments.
V. CONCLUSIONS AND RECOMMENDATIONS
The objective of this study was to develop a rainfall-runoff
model to simulate Wadi flow in Muscat, Oman. Wadi Al-
Khoud catchment area was selected. Model calibration was
Catchment area Model parameter
A11 A12 B1 A2 B2 A3 B3 A4
Al-Khoud 0.14 0.35 0.37 0.05 0.05 0.02 0.03 0.0003
Southern Japan* 0.4 0.2 0.15 0.1 0.05 0.02 0.03 0.003
Z11 Z12 Z2 Z3 H4 H3 H2 H1
Al-Khoud 1 0.1 5 10 0 0 0 0
Southern Japan* 40 15 20 10 200 40 2 1
(7)
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carried out with observations in 1997. The simulated
Wadi flow model was verified with observation in 1997,
1999, 2000 and 2004. The Nash–Sutcliffe model efficiency
coefficient of 0.88 could be obtained. The calibrated tank
model parameters in Wadi Al-koud catchment area were
compared with the parameters calibrated in several
catchments in Japan. Physical meaning of the tank model
parameters in arid environment could be successfully
interpreted. It was found that the differences of model
parameters of two catchment areas depend on vegetation
cover, topography (RG) and soil moisture content.
The tank model performance highly depends on input data
quality. Lack of long-term quality controlled rainfall and river
discharge records was a major constrain. Respective
authorities are therefore encouraged to maintain a long-term
data base to facilitate academic community.
The results of this study showed the ability of the tank
model to simulate Wadi flow with a reasonable accuracy and
therefore will be applicable for climate impact predictions. In
the next step of this study, downscaled GCMs scenarios from
several models for different climate variables will be used
with the developed tank model to simulate wadi flow
variations in future.
REFERENCES
[1] M. E. Rafy, and Y. Hafez, “Anomalies in meteorological fields over
northern Asia and its impact on Hurricane Gonu,” 28th Conference on Hurricanes and Tropical Meteorology, pp. 1–12, 2008.
[2] M. Sugawara, “On the analysis of runoff structure about several
Japanese River,” Japanese Journal of Geophysic, vol. 4, pp. 1-76, 1961. [3] L. N. Gunawardhana and S. Kazama, “A water availability and low-
flow analysis of the Tagliamento river discharge in Italy under
changing climate conditions,” Hydrology and Earth System Sciences, vol. 16, pp. 1033-1045, 2012.
[4] Y. Yokoo, S. Kazama, M. Sawamoto and H. Nishimura,
“Regionalization of lumped water balance model parameters based on multiple regression,” Journal of Hydrology, vol. 246, pp. 209-222,
2001.
[5] E. Todini, “Hydrologigal catchment modeling: past, present and future,” Hydrology and Earth System Sciences, vol. 11, pp. 468-482,
2007.
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Fig. 3. Observed and simulated wadi flows
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Mobile Ad Hoc Networks
Parth Panchal1, Meghana Shroff2 Student, III year, Bachelor of Technology (Electronics)
Mukesh Patel Institute of Technology Management and Engineering NMIMS, SVKM
Mumbai [email protected]
Abstract— A mobile ad hoc network (MANET) is a self-
configuring infrastructure-less network of mobile devices
connected by wireless. The primary challenge in building a
MANET is equipping each device to continuously maintain the
information required to properly route traffic. AODV is a novel
algorithm for the operation of such ad hoc networks. This
routing algorithm is quite suitable for a dynamic self-starting
network, as required by users wishing to utilize ad hoc
networks. AODV provides loop free routes even while repairing
broken links. We attempt to build such a network using AODV.
Keywords— MANET, AODV, Ad hoc, network simulator NS
I. INTRODUCTION
Laptop computers continue to show improvements in
convenience mobility memory capacity and availability of
disk storage. The smaller computers can be equipped with
gigabytes of disk storage high resolution color displays
pointing devices and wireless communications adapters.
Moreover because many of these small (in size only)
computers operate with battery power users are free to
move about at their convenience without being constrained
by wires. More recently the interest in this subject has
grown due to availability of license free wireless
communication devices that users of laptop computers can
use to communicate with each other. Several recent papers
on this topic have focused on the algorithmic complexity of
choosing the optimal set of ad hoc routers while others
have proposed new routing solutions leveraging features
from the existing Internet routing algorithms.
As mentioned earlier, each device in a MANET is free
to move independently in any direction, and will therefore
change its links to other devices frequently. Each must
forward traffic unrelated to its own use, and therefore be a
router. Such networks may operate by themselves or may
be connected to the larger Internet. MANETs are a kind of
Wireless ad hoc network that usually has a routable
networking environment on top of a Link Layer ad hoc
network.
A. Destination-Sequenced Distance-Vector
The Destination-Sequenced Distance-Vector (DSDV)
Routing Algorithm is based on the idea of the classical
Bellman-Ford Routing Algorithm with certain
improvements. Every mobile station maintains a routing
table that lists all available destinations, the number of
hops to reach the destination and the sequence number
assigned by the destination node. The sequence number is
used to distinguish stale routes from new ones and thus
avoid the formation of loops. The stations periodically
transmit their routing tables to their immediate neighbors.
A station also transmits its routing table if a significant
change has occurred in its table from the last update sent.
So, the update is both time-driven and event-driven.
The routing table updates can be sent in two ways: a
“full dump” or an incremental update. A full dump sends
the full routing table to the neighbors and could span many
packets whereas in an incremental update only those entries
from the routing table are sent that has a metric change
since the last update and it must fit in a packet. If there is
space in the incremental update packet then those entries
may be included whose sequence number has changed.
When the network is relatively stable, incremental updates
are sent to avoid extra traffic and full dump are relatively
infrequent. In a fast-changing network, incremental packets
can grow big so full dumps will be more frequent.
B. Dynamic State Routing (DSR)
The key distinguishing feature of DSR is the use of link
state routing. The sender/source knows the complete hop-
by-hop route. The routes are stored in route cache. A route
discovery process is used to dynamically discover routes.
Route discovery works by flooding the network with
RREQ packets. Each node receiving an RREQ rebroadcasts
it, unless it is the destination or it has a route to the
destination in its route cache. Such a node replies to the
RREQ with a route reply (RREP) packet that is routed back
to the original source. RREQ and RREP packets are also
source routed. The RREQ builds up the path traversed
across the network. The RREP routes itself back to the
source by traversing this path backward. The route carried
back by the RREP packet is cached at the source for future
use. If any link on a source route is broken, the source node
is notified using a route error (RERR) packet. The source
removes any route using this link from its cache. A new
route discovery process must be initiated by the source if
this route is still needed. DSR makes very aggressive use of
source routing and route caching.
C. Ad hoc On-Demand Distance Vector (AODV)
AODV discovers routes on an as needed basis via a
similar route discovery process. However, AODV adopts a
very different mechanism to maintain routing information.
It uses traditional routing tables, one entry per destination.
It builds routes between nodes only when it is required by
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source nodes and also it maintains these routes as
long as they are needed by these sources. AODV forms
trees which connect multicast group members. The trees
are composed of the group members and the nodes needed
to connect the members. AODV uses sequence numbers to
ensure the freshness of routes. It is loop-free, self-starting,
and scales to large numbers of mobile nodes.
Although AODV does not depend specifically on
particular aspects of the physical medium across which
packets are disseminated, its development has been largely
motivated by limited range broadcast media, such as those
utilized by infrared or radio frequency wireless
communications adapters. We do not make any attempt to
use specific characteristics of the physical medium in our
algorithm nor to handle the problems posed by
channelization needs of radio frequency transmitters.
Nodes that need to operate over multiple channels are
presumed to be able to do so. The algorithm works on
wired media as well as wireless media as long as links
along which packets may be transmitted are available. The
only requirement placed on the broadcast medium is that
neighboring nodes can detect each other’s broadcasts.
AODV uses symmetric links between neighboring nodes. It
does not attempt to follow paths between nodes when one
of the nodes cannot hear the other one however we may
include the use of such links in future enhancements.
II. AODV PROTOCOL
AODV builds routes using a route request (RREQ) and
route reply (RREP) message cycle. When a source node
desires a route to a destination for which it does not
already have a route, it broadcasts a RREQ packet to the
network. Nodes receiving this packet update their
information for the source node and set up backward
pointers to the source node in the routing tables. In
addition to the source node's IP address, current sequence
number, and broadcast ID, the RREQ also contains the
most recent sequence number for the destination of which
the source node is aware.
Fig 1: Route discovery
Fig 2: RREQ Packet Format
A node receiving the RREQ may send a RREP if it is
either the destination or if it has a route to the destination
with corresponding sequence number greater than or equal
to that contained in the RREQ. If this is the case, it unicasts
a RREP back to the source. Otherwise, it rebroadcasts the
RREQ. Nodes keep track of the RREQ's source IP address
and broadcast ID. If they receive a RREQ which they have
already processed, they discard the RREQ and do not
forward it.
Fig 3: Route reply
Figure 4: RREP Packet Format
As the RREP propagates back to the source, nodes set up
forward pointers to the destination. Once the source node
receives the RREP, it may begin to forward data packets to
the destination. If the source later receives a RREP
containing a greater sequence number or contains the same
sequence number with a smaller hop count, it may update
its routing information for that destination and begin using
the better route.
Fig 5: AODV Algorithm
As long as the route remains active, it will continue to be
maintained. Once the source stops sending data packets, the
links will time out and eventually be deleted from the
intermediate node routing tables. If a link break occurs while
the route is active, the node upstream of the break
propagates a route error (RERR) message to the source node
to inform it. After receiving the RERR, if the source node
still desires the route, it can restart route discovery.
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The algorithm’s primary objectives are:
• To broadcast discovery packets only when necessary
• To distinguish between local connectivity management
neighborhood detection and general topology
maintenance
• To disseminate information about changes in local
connectivity to those neighboring mobile nodes that are
likely to need the information
Multicast routes are set up in a similar manner. A node
wishing to join a multicast group broadcasts a RREQ with
the destination IP address set to that of the multicast group
and with the 'J'(join) flag set to indicate that it would like
to join the group. Any node receiving this RREQ that is a
member of the multicast tree that has a fresh enough
sequence number for the multicast group may send a
RREP. As the RREPs propagate back to the source, the
nodes forwarding the message set up pointers in their
multicast route tables. As the source node receives the
RREPs, it keeps track of the route with the freshest
sequence number, and beyond that the smallest hop count
to the next multicast group member. After the specified
period, the source node will unicast a Multicast Activation
(MACT) message to its selected next hop. This message
serves the purpose of activating the route. A node that does
not receive this message that had set up a multicast route
pointer will timeout and delete the pointer. If the node
receiving the MACT was not already a part of the multicast
tree, it will also have been keeping track of the best route
from the RREPs it received. Hence it must also unicast a
MACT to its next hop, and so on until a node that was
previously a member of the multicast tree is reached.
AODV maintains routes for as long as the route is
active. This includes maintaining a multicast tree for the
life of the multicast group. Because the network nodes are
mobile, it is likely that many link breakages along a route
will occur during the lifetime of that route. The only other
circumstance in which a node may change the destination
sequence number in one of its route table entries is in
response to a lost or expired link to the next hop towards
that destination.
Once the next hop becomes unreachable, the node
upstream of the break propagates an unsolicited RREP with
a fresh sequence number i.e. a sequence number that is one
greater than the previously known sequence number, and
hop count of ∞ to all active upstream neighbors. Those
nodes subsequently relay that message to their active
neighbors and so on. This process continues until all active
source nodes are notified. It terminates because AODV
maintains only loop free routes and there are only a finite
number of nodes in the ad hoc network. Consider node A
wants to connect to node B, but the link is broken in
between. This means that node A knows that the link to
node B is down and increments the Sequence number and
broadcast it.
III. SIMULATION IN NS2
We have simulated AODV using an event simulator
NS2. The main objective of our simulations is to show that
on demand route establishment with AODV is both quick
and accurate. Additional objectives include showing that
AODV scales well to large networks and determining the
optimal value for each of the necessary parameters.
A. Simulation environment
The simulation experiment is carried out in LINUX
(Ubuntu 12.04). The detailed simulation model is based on
network simulator-2 (ver-2.36), is used in the evaluation.
The NS instructions can be used to define the topology
structure of the network and the motion mode of the nodes,
to configure the service source and the receiver, to create
the statistical data track file and so on.
The following simulation results were obtained
Figure 6: Simulation scenario in the beginning
Figure 7: Simulation scenario
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Figure 8: Simulation scenario 2
Figure 9: Simulation scenario 3
Figure 10: Simulation scenario 4
B. Performance Analysis
For AODV, packet delivery ratio is independent of
offered traffic load, delivering between 85% and 100% of
the packets in all cases. The lazy approach used by AODV
to build the routing information as and when it is created
makes it more adaptive and results in better performance
(high packet delivery fraction and lower average end-to-
end packet delays). In the presence of high mobility, link
failures can happen very frequently. Link failures trigger
new route discoveries in AODV since it has at most one
route per destination in its routing table. Thus, the
frequency of route discoveries in AODV is directly
proportional to the number of route breaks.
Figure 11: Simulation scenario 5
Figure 12: Simulation scenario 6
Performance of AODV protocols in MANET can be
realized by quantitative study of values of different metrics
used to measure performance of routing protocols which
are as follows:
1) Average End-to-End Delay: It is defined as average
time taken by data packets to propagate from source to
destination across a MANET. This includes all possible
delays caused by buffering during routing discovery
latency, queuing at the interface queue, and retransmission
delays at the MAC, propagation and transfer times. The
lower value of end to end delay means better performance
of the protocol.
End to end delay = Σ (arrive time - send time)
2) Packet Delivery Ratio: It is a ratio of the number of
packets received by the destination to the number of
packets sent by the source. This illustrates the level of
delivered data to the destination. The greater value of
packet delivery ratio means better performance of the
protocol.
PDR = Σ No. of packet received / Σ No. of packet sent
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3) Packet Loss: It is the measure of number of packets
dropped by nodes due to various reasons. The lower value
of the packet lost, the better performance of the protocol.
Packet lost = No of packet sent – No of packets received.
III. CONCLUSION
In summary, we present a distance vector algorithm that
is suitable for use with ad hoc networks. AODV has the
following features:
• Nodes store only the routes that are needed
• Need for broadcast is minimized
• Reduces memory requirements and needless duplications
• Quick response to link breakage in active routes
• Loop free routes maintained by use of destination
• Sequence numbers scalable to large populations of nodes
Compared to DSDV and other algorithms which store
continuously updated routes to all destinations in the ad
hoc network our algorithm has longer latency for route
establishment. But within the limits imposed by worst case
route establishment latency, AODV is a sensible choice for
ad hoc network establishment. We look forward to further
development of the protocol for quality of service
intermediate route rebuilding and various interconnection
topologies with fixed networks and the Internet.
A. Future Scope
We believe strongly in the scope of MANET, essentially
in the form of Vehicular Ad hoc Network. Vehicular ad
hoc network is a special form of MANET which is a
vehicle to vehicle & vehicle to roadside wireless
communication network. It has great scope in vehicle
collision warning, security distance warning, driver
assistance, cooperative driving, and cooperative cruise
control, dissemination of road information, internet access,
map location, automatic parking and driverless vehicles. It
also has applications for emergency services, conferencing
battlefield communications and community based
networking.
ACKNOWLEDGMENT
We would like to express our sincere gratitude towards
Mr. Sharad Wagh, Assisstant Professor, NMIMS, for his
technical guidance and constant encouragement throughout
the project, and for his priceless inputs and patience to deal
with our queries.
We would also like to thank the authority of SVKM’s
NMIMS for providing us with a good environment and
facilities to complete this project. Without help of the
aforementioned, we would have faced many difficulties
while doing this project.
REFERENCES [1] C. Perkins, E. Belding-Royer, and S. Das. Ad hoc On- Demand
Distance Vector (AODV) Routing. RFC 3561 (Experimental), July
2003. [2] Y. C. Hu, D. Johnson, and A. Perrig. -SEAD: Secure efficient
distance vector routing for mobile wireless ad hoc networks,‖ in
Fourth IEEE Workshop on Mobile Computing Systems and Applications (WMCSA '02), 2002, p. 313.
[3] Ashokan, Manel Guerrero Zapata. -Securing ad hoc routing
protocols, 2002, ‖ in ACM workshop on Wireless security [4] S. Kent, C. Lynn, J. Mikkelson, and K. Seo. Secure border gateway
protocol (S-BGP) -real world performance and deployment issues,
2000. [5] A. Nagaraju, Dr S Ramachandram and Dr C. R. Rao. Applying
heuristic technique to ad-hoc on demand distance vector routing to
reduce broadcast, ‖ in the World Congress on Engineering Vol II, WCE 2007, London, U.K, 2007
[6] NS-2, The ns Manual (formally known as NS Documentation)
available at http: //www. isi.edu/nsnam/ ns/doc.
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Constraints Faced by Rural Women Members in
Functioning of SHGs in Allahabad District
of Uttar Pradesh Rukhsana*, Dipak Kumar Bose**, Priyanka Singh***
*Ph. D. Scholar, **Associate Professor
Departmentt of Agriculture Extension & Communication, Allahabad School of Agriculture SHIATS, Allahabad
***Assistant Professor, Department of Arts for Women
Chitamber School of Humanities Social Sciences, SHIATS, Allahabad
Abstract— The present study was undertaken to study the
constraints faced by rural women members in functioning of
Self Help Groups. Hundred and fifty rural women members of
SHGs from Allahabad district represented the sample for the
study. A structured interview schedule was used for the
collection of data. The findings revealed that the major
constraints faced by the women members were lack of formal
education, no freedom to take decisions, dominance of group
leaders, decision made at administrative level, less cooperation
of officials , less profit, travel expenses for disbursement of loan,
poor monitoring and technical guidance, inadequate space for
enterprise, high cost of raw materials, lack of storage facilities,
non-cooperation between educated and uneducated people and
non cooperation from family members. These constraints may
be solved through extension strategies like adult education,
vocational training of members, facilitating of bank officials and
providing proper marketing facilities.
I. INTRODUCTION
The SHG is a viable organized set up to disburse micro-
credit to the rural women for the purpose of making them
enterprising and encouraging to enter into entrepreneurial
activities. The formation of SHG is not ultimately a micro
credit project but an empowering process. These SHG have
common perception of need and an impulse towards
collective action. Empowering women is not just for
meeting their economic needs but also for more holistic
social development. The SHGs empower women both
socially and economically. They encourage women to
participate in decision making in the households,
community and local democratic sector and prepare women
to take up leadership position. (Ramachandran and
Balakrishnan 2008).
The SHG-Bank linkage model is the indigenous model
of micro-credit evolved in India and has been widely
acclaimed as a successful model. SHG-Bank linkage
programme is considered a promising approach to reach
the poor and has since its inception made rapid strides
exhibiting considerable democratic functioning and group
dynamism. The number of 500 Bank linked SHGs in 1991-
1992 has gone up to more than 34 lakh by the end of
March 2008. Cumulatively, these SHGs have accessed
credit of Rs. 22,268 crore from banks during the period.
About 4.1 crore poor households have gained access to the
formal banking system through the programme. The faster
growth in bank loans to SHGs has led to almost a four-fold
increase in the average loans per SHG from Rs. 16,816 in
1999-2000 to Rs. 63,926 in 2007-08. These figures reflect
the outstanding success of the programme. (Kumar and
Golait, 2009).
On the other hand it has been revealed through various
research studies that the real economic growth of the SHG
beneficiaries has not been achieved. Despite policy
initiatives, the extent of inclusion is very low in rural and
semi - urban India. There are still 90 million people who
are excluded from the formal banking system for various
reasons like lack of knowledge in the rural poor related to
banking and banking products, high transaction costs and
illiteracy. In this scenario, microfinance, which is defined
as the provision of financial services to the low income and
vulnerable groups of the society is playing a challenging
role in achieving twin goals of financial inclusion and
poverty eradication in economically viable manner. (Rupa
et al 2012)
Mehta (2012) also reported some major issues and
problems indicating SHG status. Most members of the
SHG have no knowledge about the SHG and they do not
have a principal occupation. Women member perform dual
role in society relating to production and reproduction so
they are over burdened and their contribution to the family
economy and national economy remains largely invisible
and undervalued. The existing communication channels are
not adequate and do not reach to the BPL members of the
society. There is unchecked exploitation of SHG women
members in houses, at working place and public place.
Despite all the notable efforts on part of the government
and non- government agencies, access to financial services
for all at affordable rates remains a distant dream.
Remoteness of rural areas and poor infrastructure leads to
market inefficiencies and a huge gap between demand and
supply. Problem is compounded by the fact that rural
population is still largely illiterate and not so technology
driven. Kumar and Anand (2007). Critical gaps have been
observed in the management of day to day activities of the
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Self Help Groups relating to different group
dynamics, organizational management, financial
management, arrangement of livelihood activities, internal
monitoring, accountability etc. Intensive and extensive
training programmes involving community resource
persons, coordinators will have to be organized for existing
as well as new Self-help Groups, so that village level
organizations (Primary Federations) can be conveniently
formed with the help of these groups. (Zakir et al 2011).
II. MATERIALS AND METHODS
The present research study was conducted in three
blocks of Allahabad District of UP viz; Chaka, Jasra and
Handia. A list of SHGs operating in these three blocks was
obtained from the block office. A proportionate random
sample of 30 Self Help Group was selected from the three
selected blocks. Five office bearers (women members)
from each selected Self Help Group was taken as the
sample of the study, thus a total of 150 respondents were
selected for the present study. An interview schedule was
constructed which consisted of list of statements related to
personal constraints, organizational constraints,
economic/financial constraints, managerial constraints,
social constraints and marketing related constraints. The
data was collected through personal interview method by
using pretested structured interview schedule and the
collected data were compiled, tabulated and analyzed.
III. RESULTS AND DISCUSSION
After analyzing the data regarding socio-economic
characteristics it was found that majority of the
respondents were in the age group of 30-40 years
(50.66%), married (85.33%), illiterate (48.67%), had
nuclear family (62.67%) and were daily wage labours
(48.67%).
A. Personal problems faced by the respondents
The data with regard to personal problems faced by the
respondents are presented in table 1. It is evident from the
table that majority of the respondents i.e. 68.67 per cent
faced the problem of lack of formal education and got
ranked I. TABLE I
DISTRIBUTION OF RESPONDENTS ACCORDING TO THE PERSONAL PROBLEMS FACED
N=150
Personal problems Frequency Percentage Rank
No freedom to take
decisions
42 28.00 II
Lack of motivation 26 17.33 III
Lack of formal
education
103 68.67 I
*multiple response
Most of the SHGs members were illiterate, due to which
they lack confidence and are unable to take decision at
their own. In the study it was found that about 28 percent
of the respondents had no freedom to take decisions (II
Rank) and 17.33 per cent of the respondents were those
were having the problem of lack of motivation and placed
at III rank.
B. Organisational Constraints Faced by the Respondents
The table 2 reveals the data regarding the organisational
constraints faced by the SHG members which clearly
indicates that about half of the respondents reported that
the decision related to group functioning and income
generating activities were taken at higher level and the
respondents were not involved into it. Near about 28.67 per
cent of the respondent complain of conflicts among group
members resulting in non cooperation among the group
members. TABLE II
DISTRIBUTION OF RESPONDENTS ACCORDING TO THE
ORGANIZATIONAL CONTRAINTS FACED N=150
Organizational
constraints
Frequency Percentage Rank
Dominance of group
leaders
88 58.67 I
Conflicts in group 43 28.67 V
Lack of participatory
approach
59 39.33 III
Irregular meetings 21 14.00 VII
Decision made at
administrative level
74 49.33 II
Poor record keeping 37 24.00 VI
Inadequate training 44 29.33 IV
*multiple response
The constraints of dominance of group leaders was
reported by about 58.67 per cent of the respondents (Rank
I) while 39.33 per cent were those who faced the problem
of lack of participatory approach. The problem of irregular
meeting was reported by about 14.00 per cent of the
respondents (rank VII) followed by 24.00 per cent who
complain that the records were not maintained properly
(rank VI) and about 29.33 per cent complaint of inadequate
training.
C. Economic/Financial constraints faced by the
respondents
The table 3 indicates the economic/financial constraints
faced by the SHG members. It is revealed from the table
that a large percentage of the respondents i.e. 62.67 per
cent felt that the profit earned through the income
generating activities are too little (rank I) followed by
54.67 per cent who reported that it was an extra burden for
them to arrange for travel expenses to visit the bank often.
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TABLE III
DISTRIBUTION OF RESPONDENTS ACCORDING TO THE ECONOMIC/ FINANCIAL CONSTRAINTS FACED
N=150
Economic/ Financial
constraints
Frequency Percentage Rank
Inadequate loan
transactions
32 21.33 IV
Exhaustive procedure in
getting loan
28 18.67 VI
Travel expenses for
disbursement of loan
82 54.67 II
Irregular saving
procedure and loan
repayment of members
49 32.67 III
Less cooperation of
officials
30 20.00 V
Less profit 94 62.67 I
Short duration of
repayment of loan
17 11.33 VII
*multiple response
About 21.33 per cent of the respondents reported that the
loan amount disbursed to them is insufficient to start a
profitable venture and got IV rank. The constraints at the
III rank was reported by about 32.67 per cent of the
respondents who complaint of irregular saving procedure
of the members and some of the members of SHGs did not
repay loan amount in time. About 18.67 per cent of the
respondents faced the difficulties in disbursement of loan
due to exhaustive procedure (VI rank) followed by 11.33
per cent who felt that the duration of repayment of loan is
short and must be increased and this constraints was placed
at VII rank.
D. Managerial constraints in functioning of SHGs
The data enfolded in table 4 shows the managerial
constraints faced by the respondents. It is clear from the
table that about 45.33 per cent of the respondents faced the
difficulties of poor monitoring and technical guidance (I
rank) and about 28.67 per cent of the respondents had the
constraints of lack of space for the enterprise which was
ranked II. TABLE IV
DISTRIBUTION OF RESPONDENTS ACCORDING TO MANAGERIAL CONSTRAINTS FACED
N=150
Managerial constraints Frequency Percentage Rank
No exposure in record
maintenance
38 25.33 III
Inadequate space for
enterprise
43 28.67 II
No permanency in
getting materials
32 21.33 IV
Unskilled women group
members
10 6.67 V
Poor monitoring and
technical guidance
68 45.33 I
*multiple response
About 6.67 per cent of the respondents had unskilled
women group members in their SHG followed by 25.33 per
cent who complaint of no exposure in record maintenance
and were placed at V and III rank respectively. No
permanency in getting the material was faced by about
21.33 per cent of the respondents and got IV rank.
E. Marketing Constraints Faced by the Respondents
There were some marketing related
constraints faced by the respondents which are presented in
table 5. About 36 per cent of the respondents faced the
problem of high market cost of raw material which got I
rank. The raw material for the dairy, piggery and goat
rearing is fodder and the medicines when their animals fell
ill. The market cost of veterinary drugs was perceived as
high by the respondents. SHG members engaged in
namkeen making felt the market cost of besan, peanut etc
was high. TABLE V
DISTRIBUTION OF RESPONDENTS ACCORDING TO THE MARKETING RELATED CONSTRAINTS FACED
N=150
Marketing related
constraints
Frequency Percentage Rank
No market demand of
the product
32 21.33 II
Lack of transportation 17 11.33 V
Lack of storage
facilities
22 14.67 IV
Lack of market
information
30 20.00 III
High cost of raw
materials
54 36.00 I
*multiple response
Lack of market demand of the product was faced by
about 21.33 per cent of the SHG members (II rank)
followed by 20.00 per cent who lack the information of
market demand and placed at III rank. Near about 14.67
per cent of the respondents had no storage facilities due to
lack of space while, problem of lack of transportation was
faced by about 11.33 per cent of the SHG members and
these problems got IV and V rank respectively.
F. Social Constraints Faced by the Respondents
The data set in table 6 shows the social
problems faced by the respondents. The data clearly
indicates that the problem getting rank I was faced by
about 25.33 per cent of the SHG members who reported the
problem of conflict among educated and uneducated people
due to differences in cognitive understanding. About 22.67
per cent of the respondents faced the problem of
jealousness of friends and neighbor (rank II) while only
about 7.33 per cent of the SHG members were those who
faced the problem of caste system in the group/village.
International Journal of Students’ Research in Technology & Management
Vol 2 (05), August-September 2014, ISSN 2321-2543, pg 188-191
http://www.giapjournals.org/ijsrtm.html 191
Table 6: Distribution of respondents according to the
social constraints faced by them (N=150)
Social constraints Frequency Percentage Rank
Non cooperation from
family members
17 11.33 IV
Jealousness of friends
and neighbor
34 22.67 II
Cultural taboos not
permitting
29 19.33 III
Non-cooperation
between educated and
uneducated people
38 25.33 I
*multiple response
About 11.33 per cent of the respondents faced the
problem of non cooperation of family members followed
by 19.33 per cent who faced the difficulty of cultural
taboos.
IV. CONCLUSION
The study therefore reflects that the major constraints
faced were lack of formal education, no freedom to take
decisions, dominance of group leaders, decision made at
administrative level, less cooperation of officials, less
profit, travel expenses for disbursement of loan, poor
monitoring and technical guidance, inadequate space for
enterprise, high cost of raw materials, lack of storage
facilities, non-cooperation between educated and
uneducated people and non cooperation from family
members. These constraints may be solved through
extension strategies like adult education, vocational
training of members, facilitating of bank officials and
providing proper marketing facilities.It is therefore
suggested that the women members need to be sufficiently
exposed to the objectives and functioning of the SHGs so
that they could manage the group effectively. This also will
develop their interest in undertaking various activities with
credit facilities, need based training and generate income
which will definitely make them empowered.
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