were obtained and the actions initiated to correct

deviations. It also overlooks the possibility that

the process conditions may have changed during

the response and analysis lag time. Real-time

composition monitoring and control of the

chemical and combustion processes require

sensors to overcome these limitations. Sensor

technology for gas sensing applications should

be selective, sensitive to trace species, fast, small,

accurate, reproducible, stable in extreme

environments, durable and affordable. This

invention relates to methods of monitoring

environmental variables in general and chemical

composition in particular, and sensors for such

monitoring. These low-cost sensors comprised

multiple layers in a laminated stack. Very high

numbers of sensing layers (e.g. 500) may be

incorporated into a single laminated sensor

device. The sensors may signal changes in

environmental state such as chemical

composition due to changes in sensor properties

such as resistivity, capacitance, inductance,

permittivity, permeability, refractive index,

chromaticity, transparency to light, reflection

characteristics, resonance frequency, and/or

magnetic characteristics.

Patent number: US 6202471

Publication date: 20 March 200 1

Inventors: Tapesh Yadav, Clayton Kostlecky,

William Leigh, Anthony Vigilotti, Chuanjing

Xu, Yinbao Yang

System for enhancing the sound of an acoustic instrument Applicant: Georgia Tech Research Corporation,

USA

In 1990, the ‘Mendelssohn’ Stradivarius violin

sold at Christie’s in London for $1.7 million. A

good violin at a typical music store sells for

around $2,000. The structure and geometry of

the two instruments are very similar, yet

differences in the structural dynamics of the two

instruments cause them to vibrate differently, in

turn causing differences in the sound produced

which ultimately determines quality and, to a

large extent, price. The relatively new field of

smart structural/acoustic control is centred

around changing the structural dynamics of an

acoustically radiative structure to change

(usually suppress) the sound resulting from

vibration of the structure. Smarr structural/

acoustic control also has the potential to force

one acoustically radiative structure to behave

like a target acoustically radiative structure, thus

replicating its acoustic properties. The concept

of acoustic replication using smart structures

has far-reaching implications, from the field of

acoustic musical instruments to aircraft

cockpits. This invention involves a system that

provides sound control for an acoustic musical

instrument. Typical to all acoustic instruments,

the instruments have a structure or housing that

defines a vented acoustic chamber. An input or

sound inducing mechanism (such as strings of a

guitar) imparts a vibration to the structure

which causes acoustic waves to resonate within

the acoustic chamber. The motion of air in and

out of the vent causes acoustic waves to emanate

from the chamber that combine with the

acoustic waves emanating from the structure to

form sound/musical notes. In accordance with

the invention, a system controls the sound

emanating from such an acoustic instrument. In

accordance with one embodiment of the

invention, at least one integral or smart sensor is

disposed adjacent to a sensing location of the

structure, and the sensor is configured to

generate sensed electric signals indicative of the

magnitude of structural vibration of the

structure at the sensing location. A controller in

communication with the sensor, includes a

processor for processing the sensed electric

signals in accordance with a predetermined

method (e.g. a computer program). In response,

the controller produces output electrical signals.

At leasr one integral or smart actuator is

disposed adjacent to an actuator location of the

structure, and the actuator is in communication

with the controller and is configured to receive

the output electrical signals and induce

structural vibration of the structure at the

actuator location. As a result of the structure

and operation, the induced vibration of the

structure at the actuator location creates

acoustics that alter the sound emanating from

the acoustic chamber as well as that emanating

from the structure. Specifically, signature

frequency response characteristics of acoustic

instruments - like damping and frequency

values of structural and acoustic resonances -

can be used to alter the sound of the acoustic

instruments. The use of integral or smart

sensors and actuators puts no restrictions on the

movement of the acoustic instrument player,

since they are part of the guitar structure.

Patent numbe,: US 6320 113

Publication date: 20 November 2001

Inventors: Steven F. Griffin, Chance C. McCall,

Sathya V Hanagud

Composite spoolable tube Applicant: Fiberspar Corporation, USA

It is the aim of this invention to provide an

apparatus and method for providing a

substantially non-ferrous spoolable tube that does

not suffer from the structural limitations of steel

tubing and that is capable of being deployed and

spooled under oilfield borehole conditions. The

invention provides a composite coiled tube

capable of working over wells and delivering

various chemicals down hole quickly and

inexpensively. The invention includes providing a

@ Smart Materials Bulletin February 2002

coiled tubing capable of repeated spooling and

bending without suffering fatigue sufficient to

cause fracturing and failing of the coiled tube;

being capable of carrying corrosive fluids without

causing corrosion in the tube; providing less

weight; and capable of withstanding higher

internal and external pressure levels, without

loosing tube integrity. The spoolable tube

exhibits unique anistropic characteristics that

provide improved burst and collapse pressures,

increased tensile strength, compression strength,

and load carrying capacity, while still remaining

sufftciently bendable to be spooled onto a reel in

an open bore configuration. The spoolable

composite tube can include an inner liner, an

interface layer, fibre composite layers, a pressure

barrier layer, and an outer protective layer. The

fibre composite layers can have a unique triaxial

braid structure.

Patent number: US 6286558

Publication date: 11 September 2001

Inventors: Peter A. Quigley, Stephen C. Nolet,

Jerry G. Williams

Damping vibration in turbomachine

components Applicant: United Technologies Corporation,

USA

To prevent damage to an airfoil, the

magnitudes of the steady state and vibratory

strains must not exceed the structural limits of

the airfoil. In order to keep the vibratory strain

of the airfoil within limits, the engine is often

operated at lower than optimum conditions,

resulting in a reduced engine operating

efficiency. Various approaches exist for

reducing airfoil vibration. Some involve

stiffening the structure of the airfoil or make

use of a shroud, at a midspan point on the

airfoil. Passive vibration damping is another

approach where damping employs sliding

friction devices, such as those employed under

blade platforms, relying on friction to dampen

vibratory motion with limited effectiveness.

This invention reduces the magnitude of

vibratory strain in a turbomachine component

that experiences high steady state strain. In the

case of a passive embodiment, this is achieved

by coupling a mechanical-to-electromagnetic

energy converter to an interior and/or exterior

surface of the component, and/or embedding

the energy converter within the component. In

the case of an active embodiment, this is

achieved by coupling a mechanical-to-

electromagnetic energy converter to an interior

and/or exterior surface of the component.

Patent number: US 6299410

Publication ahe: 9 October 2001

Inventors: Gary R. Hilbert, David D. Pearson,

Edward F. Crawley