Impact of Short-Cut SWCF Yarn on Conductivity and Electrical Heatability of Silicone–MWCNT Composites

The incorporation of MWCNTs in polymer systems up to the percolation range renders them electrically conductive. However, this conductivity is not high enough for heating applications in the low-voltage range (<24 V). The combination of nanoscaled MWCNTs with microscaled short SWCNT fibers that was investigated in this study causes an abrupt rise in the conductivity of the material by more than an order of magnitude. Silicone was used as a flexible and high-temperature-resistant matrix polymer. Conductive silicone coatings and films with SWCF contents of 1.5% to 5% and constant MWCNT contents of 3% and 5% were developed, and their electrical and thermal properties in the voltage range between 6 and 48 V were investigated. The electrical conductivity of 3% MWCNT composite materials rose with a 5% addition of SWCFs. Because of this spike in conductivity, output power of 1260 W/m2 was achieved, for example, for a 100 µm thick composite containing 3% MWCNT and 4% SWCF at 24 V with a line spacing of 20 cm. Thermal measurements show a temperature increase of 69 K under these conditions. These findings support the use of such conductive silicone composites for high-performance coatings and films for challenging and high-quality applications.

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Full-Bridge Active-Clamp Forward-Flyback Converter with an Integrated Transformer for High-Performance and Low Cost Low-Voltage DC Converter of Vehicle Applications

Energies ◽

10.3390/en13040863 ◽

2020 ◽

Vol 13 (4) ◽

pp. 863 ◽

Cited By ~ 1

Author(s):

Jaeil Baek ◽

Han-Shin Youn

Keyword(s):

High Power ◽

High Performance ◽

Low Voltage ◽

Low Cost ◽

Primary Root ◽

Input Voltage ◽

Oxide Semiconductor ◽

Duty Ratio ◽

Voltage Range ◽

Active Clamp

This paper presents a full-bridge active-clamp forward-flyback (FBACFF) converter with an integrated transformer sharing a single primary winding. Compared to the conventional active-clamp-forward (ACF) converter, the proposed converter has low voltage stress on the primary switches due to its full-bridge active-clamp structure, which can leverage high performance Silicon- metal–oxide–semiconductor field-effect transistor (Si-MOSFET) of low voltage rating and low channel resistance. Integrating forward and flyback operations allows the proposed converter to have much lower primary root mean square (RMS) current than the conventional phase-shifted-full-bridge (PSFB) converter, while covering wide input/output voltage range with duty ratio over 0.5. The proposed integrated transformer reduces the transformer conduction loss and simplify the secondary structure of the proposed converter. As a result, the proposed converter has several advantages: (1) high heavy load efficiency, (2) wide input voltage range operation, (3) high power density with the integrated transformer, and (4) low cost. The proposed converter is a very promising candidate for applications with wide input voltage range and high power, such as the low-voltage DC (LDC) converter for eco-friendly vehicles.

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Low-Voltage Icing Protection Film for Automotive and Aeronautical Industries

Nanomaterials ◽

10.3390/nano10071343 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1343 ◽

Cited By ~ 1

Author(s):

Liberata Guadagno ◽

Fabiana Foglia ◽

Roberto Pantani ◽

Maria Dolores Romero-Sanchez ◽

Blanca Calderón ◽

...

Keyword(s):

Energy Consumption ◽

Composite Structures ◽

High Performance ◽

Low Voltage ◽

Expanded Graphite ◽

Operating Conditions ◽

Motor Vehicles ◽

Electrically Conductive ◽

Joule Effect ◽

Conductive Films

High-performance heater films are here proposed. They manifest great applicative potentiality in the de-icing technology of aircraft and motor vehicles. The films are suitable to be integrated into composite structures for the de/anti-icing function, which can be activated if the need arises. The heating is based on the joule effect of the current flowing through the electrically conductive films. Voltage and current parameters have been set based on the generators’ capacities on-board an aircraft and a car, as well as on the energy consumption during the operating conditions and the autonomy in the time. Green processes have been employed through all preparative steps of the films, which are composed of expanded graphite (60% wt/wt) and polyvinyl alcohol (PVA) (40% wt/wt). The results reveal a very significant influence of the aspect ratio of the filler on the heating and de-icing performance and suggest how to enhance the de-icing efficiency saving energy and adapting the current on-board aircraft/car generators for de-icing operations.

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Effective Power Signal Filtering Using LC Filters with Air Core Coils

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.605.251 ◽

2014 ◽

Vol 605 ◽

pp. 251-254

Author(s):

Jose Andrés Somolinos ◽

Rafael Morales ◽

Carlos Morón ◽

Alfonso Garcia

Keyword(s):

High Performance ◽

Low Voltage ◽

Setting Time ◽

Good Time ◽

Voltage Range ◽

Dc System ◽

Air Core ◽

Wide Range ◽

Computer Controlled ◽

Lc Filter

Computer controlled power supplies are usually expensive when high performance (power, wide voltage range, low ripple factor and low response time) are required. This paper presents a simple and effective computer controlled DC system based on a commercial V/f inverter combined with a three-phase bridge rectifier and a LC power filter. Because of the widely variable frequency range of the V/f inverter when a wide range of voltage is required, amorphous or ferromagnetic core coils are avoided, and air core coils become an excellent solution to implement the filter and increase the efficiency of the power system. The proposed method for designing the LC filter is based on the full dynamic model of the filter-load set and the selection of the desired poles of the system according to the load to be coupled. The proposed topology lets obtain good time responses (setting time less than 100 ms) and good ripple factor (less than 1%) without any overshooting, even when low voltage output is required.

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Current State of Biological High-Resolution Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102985 ◽

1988 ◽

Vol 46 ◽

pp. 180-181 ◽

Cited By ~ 1

Author(s):

Klaus-Ruediger Peters

Keyword(s):

High Performance ◽

Low Voltage ◽

Backscattered Electrons ◽

Lens Position ◽

Low Voltage Operation ◽

Signal Collection ◽

Probe Size ◽

Electron Microscopes ◽

Scanning Electron Microscopes ◽

Scanning Electron

A new generation of high performance field emission scanning electron microscopes (FSEM) is now commercially available (JEOL 890, Hitachi S 900, ISI OS 130-F) characterized by an "in lens" position of the specimen where probe diameters are reduced and signal collection improved. Additionally, low voltage operation is extended to 1 kV. Compared to the first generation of FSEM (JE0L JSM 30, Hitachi S 800), which utilized a specimen position below the final lens, specimen size had to be reduced but useful magnification could be impressively increased in both low (1-4 kV) and high (5-40 kV) voltage operation, i.e. from 50,000 to 200,000 and 250,000 to 1,000,000 x respectively.At high accelerating voltage and magnification, contrasts on biological specimens are well characterized1 and are produced by the entering probe electrons in the outmost surface layer within -vl nm depth. Backscattered electrons produce only a background signal. Under these conditions (FIG. 1) image quality is similar to conventional TEM (FIG. 2) and only limited at magnifications >1,000,000 x by probe size (0.5 nm) or non-localization effects (%0.5 nm).

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Transient self back-biased buffer for low-voltage high-performance applications in standard CMOS technologies

Electronics Letters ◽

10.1049/el:19990116 ◽

1999 ◽

Vol 35 (2) ◽

pp. 112 ◽

Cited By ~ 3

Author(s):

Y. Moisiadis ◽

I. Bouras ◽

C. Papadas ◽

J.-P. Schoellkopf

Keyword(s):

High Performance ◽

Low Voltage

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A Low-Voltage High-Performance Frequency Divider exploiting Folded MCML

2021 IEEE International Symposium on Circuits and Systems (ISCAS) ◽

10.1109/iscas51556.2021.9401445 ◽

2021 ◽

Author(s):

Francesco Centurelli ◽

Giuseppe Scotti ◽

Alessandro Trifiletti ◽

Gaetano Palumbo

Keyword(s):

High Performance ◽

Low Voltage ◽

Frequency Divider

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Reliability-Oriented Design of Inverter-Fed Low-Voltage Electrical Machines: Potential Solutions

Energies ◽

10.3390/en14144144 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4144

Author(s):

Yatai Ji ◽

Paolo Giangrande ◽

Vincenzo Madonna ◽

Weiduo Zhao ◽

Michael Galea

Keyword(s):

Power Density ◽

High Speed ◽

High Performance ◽

Low Voltage ◽

Electrical Machines ◽

Design Stage ◽

Switching Frequency ◽

Special Focus ◽

Electrical Machine ◽

Engineering Approach

Transportation electrification has kept pushing low-voltage inverter-fed electrical machines to reach a higher power density while guaranteeing appropriate reliability levels. Methods commonly adopted to boost power density (i.e., higher current density, faster switching frequency for high speed, and higher DC link voltage) will unavoidably increase the stress to the insulation system which leads to a decrease in reliability. Thus, a trade-off is required between power density and reliability during the machine design. Currently, it is a challenging task to evaluate reliability during the design stage and the over-engineering approach is applied. To solve this problem, physics of failure (POF) is introduced and its feasibility for electrical machine (EM) design is discussed through reviewing past work on insulation investigation. Then the special focus is given to partial discharge (PD) whose occurrence means the end-of-life of low-voltage EMs. The PD-free design methodology based on understanding the physics of PD is presented to substitute the over-engineering approach. Finally, a comprehensive reliability-oriented design (ROD) approach adopting POF and PD-free design strategy is given as a potential solution for reliable and high-performance inverter-fed low-voltage EM design.

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A Peristaltic Micropump Based on the Fast Electrochemical Actuator: Design, Fabrication, and Preliminary Testing

Actuators ◽

10.3390/act10030062 ◽

2021 ◽

Vol 10 (3) ◽

pp. 62

Author(s):

Ilia Uvarov ◽

Pavel Shlepakov ◽

Artem Melenev ◽

Kechun Ma ◽

Vitaly Svetovoy ◽

...

Keyword(s):

High Performance ◽

Drug Delivery Systems ◽

Main Part ◽

Fabrication Technology ◽

Fabrication Procedure ◽

Order Of Magnitude ◽

Peristaltic Micropump ◽

Biomedical Field ◽

Lift Off ◽

Actuator Design

Microfluidic devices providing an accurate delivery of fluids at required rates are of considerable interest, especially for the biomedical field. The progress is limited by the lack of micropumps, which are compact, have high performance, and are compatible with standard microfabrication. This paper describes a micropump based on a new driving principle. The pump contains three membrane actuators operating peristaltically. The actuators are driven by nanobubbles of hydrogen and oxygen, which are generated in the chamber by a series of short voltage pulses of alternating polarity applied to the electrodes. This process guaranties the response time of the actuators to be much shorter than that of any other electrochemical device. The main part of the pump has a size of about 3 mm, which is an order of magnitude smaller in comparison with conventional micropumps. The pump is fabricated in glass and silicon wafers using standard cleanroom processes. The channels are formed in SU-8 photoresist and the membrane is made of SiNx. The channels are sealed by two processes of bonding between SU-8 and SiNx. Functionality of the channels and membranes is demonstrated. A defect of electrodes related to the lift-off fabrication procedure did not allow a demonstration of the pumping process although a flow rate of 1.5 µl/min and dosage accuracy of 0.25 nl are expected. The working characteristics of the pump make it attractive for the use in portable drug delivery systems, but the fabrication technology must be improved.

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