Fabrication of Carbon Fiber Embedded Carbon Aerogel via Supramolecular Assembly of Small Molecules in the Precursor Gel

2010 ◽  
Vol 146-147 ◽  
pp. 1917-1920
Author(s):  
Yuan Gang Li ◽  
Hua Jing Li ◽  
Bo Liu ◽  
An Ning Zhou ◽  
Xiao Gang Xi
Keyword(s):  
Carbon Fiber ◽  
Small Molecules ◽  
Surface Area ◽  
Supramolecular Assembly ◽  
Carbon Aerogel ◽  
Simple Addition ◽  
Electrical Conductivities ◽  
Maximum Conductivity

Carbon fiber embedded carbon aerogel (CFECA) was fabricated through simple addition of small organic gelators to the precursor formed by furfural and resorcinol. The surface area of the obtained CFECA decreased compared to that from the precursor without small gelator, but the electrical conductivities of the CFECA increased obviously. The maximum conductivity of the CFECA can reach 2.55 × 105 S/m which is more than three times as that of the referenced common carbon aerogel. The formation of CFECA was characterized by SEM as well as TEM observation.

Thermal, Raman and surface area studies of microcoiled carbon fiber synthesized by CVD microwave system

2002 ◽  
Vol 76 (3) ◽  
pp. 217-223 ◽  
Author(s):  
Jining Xie ◽  
Pramod K Sharma ◽  
V.V Varadan ◽  
V.K Varadan ◽  
Bhabendra K Pradhan ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Surface Area ◽  
Area Studies ◽  
Microwave System

A Study on Thermal and Electrical Conductivities of Ethylene-Butene Copolymer Composites with Carbon Fibers

2021 ◽  
Vol 36 (4) ◽  
pp. 417-422
Author(s):  
Y. Hamid ◽  
P. Svoboda
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Carbon Fiber ◽  
Electric Conductivity ◽  
Carbon Fibers ◽  
Mechanical Strain ◽  
Electric Resistance ◽  
Resistance Change ◽  
Electrical Conductivities ◽  
Fiber Sample

Abstract Ethylene-butene copolymer (EBC)/carbon-fiber (CF) composites can be utilized as an electromechanical material due to their ability to change electric resistance with mechanical strain. The electro-mechanical properties and thermal conductivity of ethylene butene copolymer (EBC) composites with carbon fibers were studied. Carbon fibers were introduced to EBC with various concentrations (5 to 25 wt%). The results showed that carbon fibers’ addition to EBC improves the electric conductivity up to 10 times. Increasing the load up to 2.9 MPa will raise the electric resistance change by 4 500% for a 25% fiber sample. It is also noted that the EBC/CF composites’ electric resistance underwent a dramatic increase in raising the strain. For example, the resistance change was around 13 times higher at 15% strain compared to 5% strain. The thermal conductivity tests showed that the addition of carbon fibers increases the thermal conductivity by 40%, from 0.19 to 0.27 Wm–1K–1.

scholarly journals Highly Mesoporous Carbon Aerogel as Catalyst Support in Proton Exchange Membrane Fuel Cells

2019 ◽  
Author(s):  
Kevin Gu ◽  
Eric J. Kim ◽  
Sunil K. Sharma ◽  
Keyword(s):  
Fuel Cells ◽  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Mesoporous Carbon ◽  
Proton Exchange Membrane ◽  
Catalyst Support ◽  
Carbon Aerogel ◽  
Proton Exchange ◽  
Exchange Membrane

<p>Carbon aerogel possesses unique structural and electrical properties, such as high mesopore volume, specific surface area, and electrical conductivity, which make it suitable for use as a catalyst support in Proton Exchange Membrane Fuel Cells (PEMFC). In this study, we present a novel synthesis of highly mesoporous carbon aerogel via ambient-drying and investigate its application in PEMFCs. The structural effects of activation on carbon aerogel were also studied. The TEM, XRF, Non Localized Density Function Theory (NLDFT) and BJH analysis were carried out to observe the morphology and pore structure. Pt on carbon aerogel and activated carbon aerogel show efficient activity in both oxygen reduction and hydrogen oxidation reactions compared to Pt on Vulcan XC-72, with increases up to 715% and 195% in specific power density, respectively. The enhanced performance of carbon aerogel is attributed to its large specific surface area and high mesopore to micropore ratio. Accelerated stress tests show that carbon aerogel has comparable durability with Vulcan XC-72, while activated carbon aerogel is less durable than both materials. Thus, the mesoporous carbon aerogel provides an efficient, lower-cost alternative to existing microporous carbon material as a catalyst support in PEMFCs.</p><p></p>

Effects of coronary flow reduction on capillary-myocardial exchange in dogs

1978 ◽  
Vol 234 (6) ◽  
pp. H679-H689 ◽  
Author(s):  
T. R. Harris ◽  
C. A. Gervin ◽  
D. Burks ◽  
P. Custer
Keyword(s):  
Small Molecules ◽  
Surface Area ◽  
Coronary Flow ◽  
Paired Comparison ◽  
Tritiated Water ◽  
Flow Reduction ◽  
Flow Restriction ◽  
Permeability Surface ◽  
Control Situations ◽  
Multiple Indicator

The effects of coronary flow reduction on tracer capillary permeability surface area (PS) and distribution volumes were studied in open-chest dog preparations. A mixture of 51Cr-labeled red blood cells, 125I-labeled albumin, [14C]sucrose, and tritiated water (3H2O) was introduced into a shunt connecting the carotid and left anterior descending coronary arteries. Sampling from the coronary sinus produced a multiple indicator curve from which [14C]sucrose PS and 3H2O volumes were computed. Curves were observed in control situations and after the cannula was partially clamped. In six dogs, cardiac lymph was collected and analyzed for total protein. Paired comparison of control and flow-restricted indicator curves showed that flow reduction decreased the absolute values of PS and tracer volumes. The ratio of sucrose volume to weight of perfused tissue increased with flow reduction. The ratio of sucrose PS to weight of perfused tissue increased with moderate flow reduction and decreased with severe flow reduction. The results suggest that flow reduction has two effects which competively affect exchange: 1) flow restriction reduces surface area by capillary derecruitment, and 2) the remaining functional capillaries appear to undergo an increase in permeability to small molecules.

Effect of Impurity and Gas Nature on Microstructure of SiC Microtubes in Double Step Reaction Process

2006 ◽  
Vol 510-511 ◽  
pp. 302-305
Author(s):  
Sang Won Myoung ◽  
Jin Ho Kang ◽  
Seong Hwan Park ◽  
Seoung Soo Lee ◽  
Dong Won Joo ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Surface Area ◽  
Carbon Fibers ◽  
Hydrogen Gas ◽  
Reaction Process ◽  
Qualitative Properties ◽  
Double Step ◽  
Small Surface ◽  
Membrane Type ◽  
Fiber Preforms

A novel process in the synthesis of SiC microtubes is proposed, based on modified CVD process. This process was adopted to siliconize the carbon fibers that perform with relatively small surface area, either partially or completely, into the SiC microtubes with large surface area. An oxidic vapor generated from a metal reacts with a carbon solid preform, which leads to a carbide possessing with a unique morphology. The carbon fiber preforms have been unidirectionally arranged into alumina tube, and then a solid-vapor reaction between carbon fiber preforms and SiO vapor originated from the mixture powder pack of Si and SiO2 has been carried out in restoration atmosphere (argon gas/hydrogen gas = 80/20) at 1450°C. The synthesized SiC.C composites were re-sintered with the modified mixture powder pack of Si, SiO2, Al, and Al2O3 at the same condition, in which amounts of Al and Al2O3 employed as a impurity have been controlled under 1 wt% with different mole ratios (Al2O3 : Al = 1:1, 2:1, 3:1). Two kinds of SiO and AlO vapors are generated in the second step reaction process, which react with carbon residuals. The quantitative and qualitative properties of the SiC micorotubes were analyzed by using TGA, SEM, and XRD. The inner morphology of the SiC micorotubes is dependent on the impurity concentration and the gas nature, showing the grains grown with membrane type in the second reaction process because of the impurity.

scholarly journals From double-helix structured seaweed to S-doped carbon aerogel with ultra-high surface area for energy storage

2019 ◽  
Vol 17 ◽  
pp. 22-30 ◽  
Author(s):  
Daohao Li ◽  
Guojing Chang ◽  
Lu Zong ◽  
Pan Xue ◽  
Yu Wang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Surface Area ◽  
Double Helix ◽  
High Surface ◽  
High Surface Area ◽  
Carbon Aerogel
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