Flexible Integrated Sensors: Transverse Piezoresistance and Longitudinal Thermal Resistance of One Single Carbon Fiber Beam

2019 ◽  
Vol 4 (12) ◽  
pp. 1900802
Author(s):  
Jingcheng Huang ◽  
Guoning Chen ◽  
Xiaoyan Hu ◽  
Songhui Li ◽  
Jingxiu Wen ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Thermal Resistance ◽  
Integrated Sensors ◽  
Transverse Piezoresistance

Hydrodynamic and Thermal Performance of a Vapor-Venting Microchannel Copper Heat Exchanger

2008 ◽  
Author(s):  
Milnes P. David ◽  
Amy Marconnet ◽  
Kenneth E. Goodson
Keyword(s):  
Heat Exchanger ◽  
Carbon Fiber ◽  
Pressure Drop ◽  
Thermal Resistance ◽  
Heat Exchangers ◽  
Single Phase ◽  
Two Phase ◽  
Microchannel Heat Exchanger ◽  
Large Pressure ◽  
Dry Out

Two-phase microfluidic cooling has the potential to achieve low thermal resistances with relatively small pumping power requirements compared to single-phase heat exchanger technology. Two-phase cooling systems face practical challenges however, due to the instabilities, large pressure drop, and dry-out potential associated with the vapor phase. Our past work demonstrated that a novel vapor-venting membrane attached to a silicon microchannel heat exchanger can reduce the pressure drop for two-phase convection. This work develops two different types of vapor-venting copper heat exchangers with integrated hydrophobic PTFE membranes and attached thermocouples to quantify the thermal resistance and pressure-drop improvement over a non-venting control. The first type of heat exchanger, consisting of a PTFE phase separation membrane and a 170 micron thick carbon-fiber support membrane, shows no improvement in the thermal resistance and pressure drop. The results suggest that condensation and leakage into the carbon-fiber membrane suppresses venting and results in poor device performance. The second type of heat exchanger, which evacuates any liquid water on the vapor side of the PTFE membrane using 200 ml/min of air, reduces the thermal resistance by almost 35% in the single-phase regime in comparison. This work shows that water management, mechanical and surface properties of the membrane as well as its attachment and support within the heat exchanger are all key elements of the design of vapor-venting heat exchangers.

scholarly journals Online Monitoring of Moisture Diffusion in Carbon Fiber Composites Using Miniaturized Flexible Material Integrated Sensors

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1748
Author(s):  
Martina Hübner ◽  
Dennis Lepke ◽  
Elisabeth Hardi ◽  
Michael Koerdt ◽  
Axel S. Herrmann ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Online Monitoring ◽  
Fiber Composite ◽  
Moisture Diffusion ◽  
Fiber Composites ◽  
Carbon Fiber Composites ◽  
Integrated Sensors ◽  
Monitoring Method ◽  
Moisture Measurement ◽  
Flexible Material

Moisture diffusion in carbon fiber composites changes the mechanical properties of the composite. Therefore, a monitoring method of the actual content of moisture in the composite is important. However, at the moment there are no online methods established. A common method is the measurement of the mass changes due to water uptake. This method is not suitable for online monitoring of a real composite part in service. We demonstrate that miniaturized flexible interdigital sensors are suitable for moisture measurement inside the carbon fiber composite. These sensors are directly integrated inside the composite. It was already demonstrated that these can be successfully used for resin-curing monitoring as a primary application. Here we demonstrate that the same sensors are also suitable for moisture measurement inside the material. In order to do so, we expose samples with and without integrated sensors to hot-wet conditions and measure the dielectric changes with the sensors and the mass gain. The moisture concentration and the measured admittance can be directly correlated to each other. This demonstrates that the sensors can be used for moisture measurement as a secondary application. In addition, it is shown that the sensors have the potential to measure the moisture locally inside the material.

Reduction of Thermal Resistance of High-Power Amplifiers by Carbon Fiber-Reinforced Carbon Composite-Based Package

2012 ◽  
Vol 2 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Naotaka Kuroda ◽  
Akio Wakejima ◽  
Masahiro Tanomura ◽  
Kazuki Ota ◽  
Yuji Ando ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Thermal Resistance ◽  
High Power ◽  
Power Amplifiers ◽  
Carbon Composite ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced

Effects of high pressure on the crystallization of carbon fiber reinforced polyetheretherketone (CF/PEEK) laminate composites

1990 ◽  
Vol 48 (4) ◽  
pp. 876-877
Author(s):  
Hong-Ming Lin ◽  
C. H. Liu ◽  
R. F. Lee
Keyword(s):  
High Pressure ◽  
Carbon Fiber ◽  
Sample Surface ◽  
High Yield ◽  
Fiber Reinforced ◽  
Laminate Composites ◽  
Peek Composite ◽  
Continuous Carbon Fiber ◽  
Carbon Fiber Reinforced

Polyetheretherketone (PEEK) is a crystallizable thermoplastic used as composite matrix materials in application which requires high yield stress, high toughness, long term high temperature service, and resistance to solvent and radiation. There have been several reports on the crystallization behavior of neat PEEK and of CF/PEEK composite. Other reports discussed the effects of crystallization on the mechanical properties of PEEK and CF/PEEK composites. However, these reports were all concerned with the crystallization or melting processes at or close to atmospheric pressure. Thus, the effects of high pressure on the crystallization of CF/PEEK will be examined in this study.The continuous carbon fiber reinforced PEEK (CF/PEEK) laminate composite with 68 wt.% of fibers was obtained from Imperial Chemical Industry (ICI). For the high pressure experiments, HIP was used to keep these samples under 1000, 1500 or 2000 atm. Then the samples were slowly cooled from 420 °C to 60 °C in the cooling rate about 1 - 2 degree per minute to induce high pressure crystallization. After the high pressure treatment, the samples were scanned in regular DSC to study the crystallinity and the melting temperature. Following the regular polishing, etching, and gold coating of the sample surface, the scanning electron microscope (SEM) was used to image the microstructure of the crystals. Also the samples about 25mmx5mmx3mm were prepared for the 3-point bending tests.

Enhanced performance of supercapacitors by constructing a “mini parallel-plate capacitor” in an electrode with high dielectric constant materials

2020 ◽  
Vol 8 (32) ◽  
pp. 16661-16668
Author(s):  
Huayao Tu ◽  
Shouzhi Wang ◽  
Hehe Jiang ◽  
Zhenyan Liang ◽  
Dong Shi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Carbon Fiber ◽  
Parallel Plate ◽  
Sandwich Structure ◽  
High Dielectric Constant ◽  
Parallel Plate Capacitor ◽  
Plate Capacitor ◽  
Fiber Metal ◽  
High Dielectric ◽  
Mini Plate

The carbon fiber/metal oxide/metal oxynitride layer sandwich structure is constructed in the electrode to form a mini-plate capacitor. High dielectric constant metal oxides act as dielectric to increase their capacitance.

Contact lens with integrated sensors for the next generation of human health monitoring

2011 ◽  
Author(s):  
Huanfen Yao ◽  
Ilkka Lahdesmaki ◽  
Babak A. Parviz
Keyword(s):  
Human Health ◽  
Health Monitoring ◽  
Contact Lens ◽  
Next Generation ◽  
Integrated Sensors

Modification of activated carbon fiber pore structure by coke deposition

2001 ◽  
Vol 11 (PR3) ◽  
pp. Pr3-279-Pr3-286
Author(s):  
X. Dabou ◽  
P. Samaras ◽  
G. P. Sakellaropoulos
Keyword(s):  
Activated Carbon ◽  
Carbon Fiber ◽  
Pore Structure ◽  
Activated Carbon Fiber ◽  
Coke Deposition
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