scholarly journals Spatial Distribution of Oxygen Chemical Potential under Potential Gradients and Theoretical Maximum Power Density with 8YSZ Electrolyte

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Dae-Kwang Lim ◽  
Ha-Ni Im ◽  
Sun-Ju Song
Keyword(s):  
Spatial Distribution ◽  
Power Density ◽  
Chemical Potential ◽  
Maximum Power ◽  
Maximum Power Density ◽  
Theoretical Maximum ◽  
Potential Gradients ◽  
Oxygen Chemical Potential

Carbon Nano Tube-Polymer Hybrid Nanocomposite Electrodes for Porous Polydimethylsiloxane Sponge-Based Flexible Triboelectric Nanogenerators

2021 ◽  
Vol 21 (9) ◽  
pp. 4680-4684
Author(s):  
Dae-Hyeon Kwon ◽  
Jaebum Jeong ◽  
Yongju Lee ◽  
Jun-Kyu Park ◽  
Suwoong Lee ◽  
...  
Keyword(s):  
Power Density ◽  
Output Voltage ◽  
Maximum Power ◽  
Maximum Power Density ◽  
Flexible Electrodes ◽  
Flexible Devices ◽  
Copper Electrodes ◽  
Polymer Hybrid ◽  
Triboelectric Nanogenerators ◽  
Carbon Nano Tube

Flexible triboelectric nanogenerators (TENGs) have attracted much attention because of its environmentally friendly, practical, and cost-producing advantages. In flexible TENGs, it is important to study the flexible electrodes in order to fabricate the fully flexible devices. Here, we compared electrical characteristics of the sponge porous polydimethylsiloxane (PDMS)-based flexible TENGs with two types of flexible electrodes, copper and carbon nanotube (CNT)-PDMS electrodes. The output voltage and maximum power density of sponge PDMS-based flexible TENGs with copper and CNTPDMS electrodes were compared. The voltage and power density of sponge PDMS-based flexible TENGs with CNT-PDMS electrodes were improved compare to those with copper electrodes. The output voltage and the maximum power density of sponge PDMS-based flexible TENGs with copper and CNT-PDMS electrodes increased 4 times and 7 times, respectively. It is attributed to higher electrical conductivity and stably flow electricity of CNT than those of copper.

Influence of Composition of Gd-Doped Ceria Electrolyte on Performance of Solid Oxide Fuel Cell

2012 ◽  
Vol 724 ◽  
pp. 389-392 ◽  
Author(s):  
Yuta Ibusuki ◽  
Yoshihiro Hirata ◽  
Soichiro Sameshima ◽  
Naoki Matsunaga
Keyword(s):  
Power Density ◽  
Open Circuit ◽  
Solid Oxide ◽  
Maximum Power ◽  
Cell Performance ◽  
Excess Oxygen ◽  
Doped Ceria ◽  
Oxide Fuel ◽  
Maximum Power Density ◽  
Oxide Ion Conductivity

Cell performance was measured for four types of Ni (40 vol%)-Gd-doped ceria (GDC) anode-supported solid oxide fuel cells with GDC electrolyte (40-120 μm thickness) of Ce1-xGdxO2-x/2 compositions (x = 0.05, 0.1, 0.15 and 0.2) at 773-1073 K using a H2 fuel. (La0.8Sr0.2)(Co0.8Fe0.2)O3 cathode was printed on the GDC films. The open circuit voltage and maximum power density at 873-1073 K showed a maximum at x = 0.1. The maximum power density at x = 0.1 was 166 and 506 mW/cm2 at 873 and 1073 K, respectively. The excess oxygen vacancy at x = 0.1-0.2, which does not contribute to the oxide ion conductivity, reacts with a H2 fuel to form electrons (H2 + VO 2H+ + VO×, VO× VO + 2e-). This reaction reduces the cell performance.

Performance comparison of an irreversible closed variable-temperature heat reservoir brayton cycle under maximum power density and maximum power conditions

2005 ◽  
Vol 219 (7) ◽  
pp. 559-565 ◽  
Author(s):  
L Chen ◽  
J Zheng ◽  
F Sun ◽  
C Wu
Keyword(s):  
Power Density ◽  
Heat Exchangers ◽  
Variable Temperature ◽  
Thermal Capacity ◽  
Maximum Power ◽  
Working Fluid ◽  
Brayton Cycle ◽  
Maximum Power Density ◽  
Temperature Ratio ◽  
Temperature Heat

The power density is taken as an objective for performance analysis of an irreversible closed Brayton cycle coupled to variable-temperature heat reservoirs. The analytical formulas about the relationship between power density and working fluid temperature ratio (pressure ratio) are derived with the heat resistance losses in the hot- and cold-side heat exchangers, the irreversible compression and expansion losses in the compressor and turbine, and the effect of the finite thermal capacity rate of the heat reservoirs. The obtained results are compared with those results obtained by using the maximum power criterion. The influences of some design parameters, including the temperature ratio of the heat reservoirs, the effectivenesses of the heat exchangers between the working fluid and the heat reservoirs, and the efficiencies of the compressor and the turbine, on the maximum power density are provided by numerical examples, and the advantages and disadvantages of maximum power density design are analysed. The power plant design with maximum power density leads to a higher efficiency and smaller size. When the heat transfers between the working fluid and the heat reservoirs are carried out ideally and the thermal capacity rates of the heat reservoirs are infinite, the results of this article become similar to those obtained in the recent literature.

Power Density Analysis for a Regenerated Closed Brayton Cycle

2001 ◽  
Vol 08 (04) ◽  
pp. 377-391 ◽  
Author(s):  
Lingen Chen ◽  
Junlin Zheng ◽  
Fengrui Sun ◽  
Chih Wu
Keyword(s):  
Power Density ◽  
Heat Exchangers ◽  
Pressure Ratio ◽  
Maximum Power ◽  
Design Parameters ◽  
Working Fluid ◽  
Brayton Cycle ◽  
Maximum Power Density ◽  
Recovery Coefficient ◽  
Advantages And Disadvantages

In this paper, the power density, defined as the ratio of power output to the maximum specific volume in the cycle, is set as the objective for performance analysis of an irreversible, regenerated and closed Brayton cycle coupled to constant-temperature heat reservoirs from the viewpoint of finite time thermodynamics (FTT) or entropy generation minimization (EGM). The analytical formulae about the relations between power density and pressure ratio are derived with the heat resistance losses in the hot- and cold-side heat exchangers and the regenerator, the irreversible compression and expansion losses in the compressor and turbine, and the pressure loss in the pipe. The results obtained are compared with those obtained by using the maximum power criterion. The influences of some design parameters, including the effectiveness of the regenerator, the temperature ratio of heat reservoirs, the effectivenesses of heat exchangers between working fluid and heat reservoirs, the efficiencies of the compressor and the turbine, and the pressure recovery coefficient, on the maximum power density are illustrated by numerical examples, and advantages and disadvantages of maximum power density design are analyzed. When heat transfers between working fluid and heat reservoirs are carried out ideally, the results of this paper coincide with those obtained in recent literature.

scholarly journals Natural Wolframite Used as Cathode Photocatalyst for Improving the Performance of Microbial Fuel Cells

2018 ◽  
Vol 8 (12) ◽  
pp. 2504
Author(s):  
Junxian Shi ◽  
Anhuai Lu ◽  
Haibin Chu ◽  
Hongyu Wu ◽  
Hongrui Ding
Keyword(s):  
Fuel Cells ◽  
Power Density ◽  
Microbial Fuel Cells ◽  
Environmental Remediation ◽  
Low Cost ◽  
Reduction Process ◽  
Maximum Power ◽  
Maximum Power Density ◽  
Graphite Cathode ◽  
Vis Spectroscopy

Developing simple and cheap electrocatalysts or photocatalysts for cathodes to increase the oxygen reduction process is a key factor for better utilization of microbial fuel cells (MFCs). Here, we report the investigation of natural wolframite employed as a low-cost cathode photocatalyst to improve the performance of MFCs. The semiconducting wolframite was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. The band gap and photo respond activities were determined by UV-vis spectroscopy and linear sweep voltammetry (LSV), respectively. Compared with the normal graphite cathode, when MFCs were equipped with a wolframite-coated cathode, the maximum power density was increased from 41.47 mW·m−2 to 95.51 mW·m−2. Notably, the maximum power density further improved to 135.57 mW·m−2 under light irradiation, which was 2.4 times higher than with a graphite cathode. Our research demonstrated that natural wolframite, a low-cost and abundant natural semiconducting mineral, showed promise as an effective photocathode catalyst which has great potential applications related to utilizing natural minerals in MFCs and for environmental remediation by MFCs in the future.

scholarly journals Forevacuum plasma source of continuous electron beam

2019 ◽  
Vol 37 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Aleksandr Klimov ◽  
Ilya Bakeev ◽  
Efim Oks ◽  
Aleksey Zenin
Keyword(s):  
Electron Beam ◽  
Power Density ◽  
Hollow Cathode ◽  
Plasma Source ◽  
Electron Source ◽  
Hollow Cathode Discharge ◽  
Maximum Power ◽  
Maximum Power Density ◽  
Plasma Cathode ◽  
Pressure Plasma

AbstractWe describe here the design, main parameters, and characteristics of a forevacuum-pressure plasma-cathode electron source based on a hollow-cathode discharge. The source generates a continuous focused electron beam with energy up to 30 keV and current up to 300 mA at a pressure of 10–50 Pa. The focused electron beam reaches a maximum power density of 106 W/cm2. The source utility has been demonstrated by its application for processing and cutting of ceramic.

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