Many of the recent advances in enhancing the thermoelectric figure of merit are linked to nanoscale phenomena found both in bulk samples containing nanoscale constituents and in nanoscale samples themselves. Prior theoretical and experimental proof-of-principle studies on quantum-well superlattice and quantum-wire samples have now evolved into studies on bulk samples containing nanostructured constituents prepared by chemical or physical approaches. In this Review, nanostructural composites are shown to exhibit nanostructures and properties that show promise for thermoelectric applications, thus bringing together low-dimensional and bulk materials for thermoelectric applications. Particular emphasis is given in this Review to the ability to achieve 1) a simultaneous increase in the power factor and a decrease in the thermal conductivity in the same nanocomposite sample and for transport in the same direction and 2) lower values of the thermal conductivity in these nanocomposites as compared to alloy samples of the same chemical composition. The outlook for future research directions for nanocomposite thermoelectric materials is also discussed.

https://www.bc.edu/content/dam/files/schools/cas_sites/physics/pdf/Ren/AdvMater_19_1043_2007.pdf

New Directions for Low-Dimensional Thermoelectric Materials**

A method of fusing biomaterial and tissue using radiofrequency energy includes the steps of: providing a vessel sealing instrument having opposing jaw members which are movable relative to one another to compress tissue therebetween. The vessel sealing instrument includes at least one stop member affixed thereto for regulating the distance between the opposing jaw members. The method also includes the steps of: providing a biomaterial; positioning the biomaterial in abutting relation to tissue; approximating the biomaterial and tissue between the jaw members; compressing the biomaterial and tissue between the jaw members under a working pressure within the range of about 3 kg/cm 2 to about 16 kg/cm 2 ; and energizing the jaw members with radiofrequency energy to effectively fuse the biomaterial and the tissue such that the biomaterial and the tissue reform into a single, fused mass.

Method of fusing biomaterials with radiofrequency energy

A laparoscopic bipolar electrosurgical instrument for sealing tissue includes a handle having an elongated tube affixed thereto. The tube includes first and second jaw members having electrically conductive sealing surfaces attached to a distal end thereof which are movable from a first position for approximating tissue to a second position for grasping tissue therebetween. The handle includes a fixed handle and a handle which is movable relative to the fixed handle to effect movement of the jaw members from the first position to the second position for grasping tissue. The jaw members connect to a source of electrosurgical energy such that the opposable sealing surfaces are capable of conducting electrosurgical energy through tissue held therebetween. A stop is included for maintaining a minimum separation distance between opposing sealing surfaces. A ratchet is also included to maintain a closure force in the range of about 7 kg/cm 2 to about 13 kg/cm 2 between opposing sealing surfaces.

Laparoscopic bipolar electrosurgical instrument

An electrosurgical system is disclosed. The electrosurgical system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue. The electrosurgical generator includes impedance sensing circuitry which measures impedance of tissue, a microprocessor configured to determine whether a tissue reaction has occurred as a function of a minimum impedance value and a predetermined rise in impedance, wherein tissue reaction corresponds to a boiling point of tissue fluid, and an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue.

Vessel sealing system

An endoscopic forceps includes a housing having a shaft attached thereto, the shaft including a pair of jaw members disposed at a distal end thereof. The forceps also includes a drive assembly disposed in the housing which moves the jaw members relative to one another from a first position wherein the jaw members are disposed in spaced relation relative to one another to a second position wherein the jaw members are closer to one another for manipulating tissue. A pair of handles is operatively connected to the drive assembly and the handles are movable relative to the housing to actuate the drive assembly to move the jaw members. Each of the jaw members is adapted to connect to a source of electrical energy such that the jaw members are capable of conducting energy for treating tissue. The forceps also includes a first switch disposed on the housing which is activatable to selectively deliver energy of a first electrical potential to at least one jaw member for treating tissue in a monopolar fashion. A second switch is disposed on the housing and is activatable to selectively deliver energy of a first electrical potential to one jaw member and selectively deliver energy of a second electrical potential to the other jaw member for treating tissue in a bipolar fashion.

In-line vessel sealer and divider

for materials. This journal paper detail enables the researcher to readily reproduce many of the materials presented. The chapters on conductive polymers range from uses for anticorrosion, electrochemical processes, carbon films and synthesis of various well-known conducting polymers. Applications of conductive polymers discussed include transparent/flexible electrodes, static discharge, EM1 shielding, polymer batteries, microelectronics and electro-chromic devices. Each chapter reviews the basic fundamentals of electronic conduction process for the materials being discussed, material processing and current applications. The chapters on linear and nonlinear materials used for electro-optic applications include modulator waveguides, light emission, electrical properties of ion-implanted polymers, and various optical properties. There are also chapters on various other topics on the electrical properties of polymer gels, ferroelectric liquid crystalline polymers, and electro-active polymers for biomedical applications. This reference book would be useful to those in the field of conductive polymers and electro-optic devices that use polymers as the active media. This book provides up-to-date information in the field of conductive polymers and polymers used in electro-optical devices as well as lists of recent references with each chapter.

Handbook of Instrumental Techniques for Analytical Chemistry

This is a classic reference text that has been updated and revised to include some recent developments in polymer science, including topics on nanocomposites, DNA and proteins, and glass transition of nano-thin film plastics. Although the coverage of the new topics does not do them justice, the strength of this book remains in the fundamentals. Some of the topics covered include: the basic structure of common polymers; chain structure; molecular weights; concentrated solutions; the amorphous state; the crystalline state; glass transition; cross-linking; and polymer blends. The text is well written, and there are many illustrations, photographs, graphs and tables. The book is easy to follow and understand and is highly recommended as a basic text on polymer science or as a textbook for undergraduate studies. It could also be used by engineers and scientists working in the filed who need a good book on fundamentals.

Introduction to Physical Polymer Science, 4th Edition [Book Review]

A shorting system, which eliminates persistent arcing faults in power distribution equipment, includes a first shorting switch having separable contacts, an actuation input and a fuse electrically connected in series with those contacts. A second shorting switch includes an actuation input and separable contacts, which are electrically connected in parallel with the series combination of the fuse and the first shorting switch contacts. A detection circuit includes one or more arcing light sensors and an actuation circuit. The light sensors detect arcing fault light and the actuation circuit responsively outputs a first trigger signal to the first shorting switch actuation input to close its contacts. For a persistent arcing fault, which is not eliminated by the first shorting switch, a predetermined time after the first trigger signal, the actuation circuit responsively outputs a second trigger signal to the second shorting switch actuation input to close its contacts.

System for eliminating arcing faults and power distribution system employing the same

Under certain circumstances, unintentional series arcing, caused from damaged line cords and loose connections, can pose a serious fire and safety hazard. This work, focusing on residential 115 V/sub ac/ applications, shows how continuous bursts of ignited gases can be created from overheated PVC insulation created from glowing contacts with subsequent series arcing, or surface breakdown with subsequent series arcing. Also, surprisingly, these potentially hazardous fire conditions were created with currents as low as 0.9 A/sub rms/, at 115 V/sub ac/ (100 W lamp load). Little research is available about the interaction of glowing contacts, formed from loose or broken copper conductors in wiring (outlets, switches, line conductors, etc.), with electrical insulation. This work shows how glowing contacts and surface arcing can decompose PVC insulation, form ignitable gases, and that it is possible for the subsequent series arc to ignite, and burn insulation. Two conditions are identified that can create an overheated connection - a glowing contact and/or breakdown over a charred insulation surface. Mechanisms are discussed along with data for glowing contact voltage drop, photographs of glowing connections, and a gas chromatograph analysis of the evolved gases emitted from overheated PVC wiring. Selected high-speed video frames (1000 fps) taken from videos of the series arc and bursts of ignitable gasses along with synchronized current and voltage waveforms over a current range of 0.9 A/sub rms/ to 5 A/sub rms/ are presented. These findings are useful for advancing the state-of-the-art in fire protection by providing a better understanding of how electrical fires can initiate.

Conditions for series arcing phenomena in PVC wiring

Arcing faults in electric power systems, such as switchgear, are detected by gathering light from components in the system and splitting the gathered light into two beams. The first beam is passed through a first narrow band filter to extract a wavelength characteristic of arcing in the material of the selected component, such as the copper in the switchgear conductors. The second beam is passed through a second filter having a narrow bandwidth, not including the characteristic wavelength. The extracted light signals are converted to a sensed light electrical signal and a background light electrical signal, respectively, by photodiodes and compared. If the sensed light electrical signal exceeds the background light electrical signal by a selected threshold, an output device such as a trip solenoid is actuated.

John J. Shea

Papers

Handbook of Instrumental Techniques for Analytical Chemistry

Introduction to Physical Polymer Science, 4th Edition [Book Review]

System for eliminating arcing faults and power distribution system employing the same

Conditions for series arcing phenomena in PVC wiring

Apparatus and method for optically detecting arcing faults in electric power systems in the presence of other light sources