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(1 - 5 of 5)
- Title
- Carbon nano-fibers for electrochemical double-layer capacitors.
- Creator
- Cao, Xuejun., Florida Atlantic University, Lipka, Stephen M.
- Abstract/Description
-
A novel carbon nano-fiber was prepared using catalytic vapor phase growth. Electrochemical capacitors were assembled using these fibers. Physical analysis was conducted on the carbon nano-fibers and electrochemical analysis was performed on capacitors made from these carbon nano-fibers. Scanning electron microscopy revealed that the nano-fibers had diameters ranging from 20nm to 400nm. X-ray diffraction showed the nano-fibers were more ordered than some commercial carbon fibers. BET...
Show moreA novel carbon nano-fiber was prepared using catalytic vapor phase growth. Electrochemical capacitors were assembled using these fibers. Physical analysis was conducted on the carbon nano-fibers and electrochemical analysis was performed on capacitors made from these carbon nano-fibers. Scanning electron microscopy revealed that the nano-fibers had diameters ranging from 20nm to 400nm. X-ray diffraction showed the nano-fibers were more ordered than some commercial carbon fibers. BET adsorption yielded specific surface areas of the nano-fibers at around 400 m$\sp2$/g. Electrochemical studies including cyclic voltammetry and electrochemical impedance spectroscopy indicated that capacitors made from carbon nano-fibers were promising for practical use. Further modification/activation of the carbon nano-fibers was conducted and capacitors made from these materials were also evaluated.
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/15622
- Subject Headings
- Capacitors, Electric double layer, Carbon fibers
- Format
- Document (PDF)
- Title
- Electrochemical double-layer capacitors utilizing low surface area graphite fibers.
- Creator
- Zawacki, David Isaiah., Florida Atlantic University, Lipka, Stephen M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Electrochemical double-layer capacitors were constructed using low surface area carbon fibers that are commercially available. The fibers were made from polyacrylonitrile (PAN) and pitch and vary from low (LC = 14A, d002 = 3.54A) to high (LC = 169A, d002 = 3.40A) crystallinity. High energy densities (up to 7.83 Wh/kg) were obtained by electrochemically intercalating HSO4- ions between the graphene planes of the carbon fibers. The intercalation process was strongly influenced by the...
Show moreElectrochemical double-layer capacitors were constructed using low surface area carbon fibers that are commercially available. The fibers were made from polyacrylonitrile (PAN) and pitch and vary from low (LC = 14A, d002 = 3.54A) to high (LC = 169A, d002 = 3.40A) crystallinity. High energy densities (up to 7.83 Wh/kg) were obtained by electrochemically intercalating HSO4- ions between the graphene planes of the carbon fibers. The intercalation process was strongly influenced by the crystallinity of the carbon fiber and by the precursors from which the fiber was manufactured. All the pitch fibers had a higher structural order and a higher carbon content than the PAN fibers. A total of 10 capacitors were constructed. Nine of these were constructed from fibers that were electrochemically activated and one was constructed from fiber as received. 38 w/o sulfuric acid was used as the electrolyte for each of these capacitors. Performance of the capacitors decreased as the structural order and carbon content of the fibers decreased.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15427
- Subject Headings
- Capacitors, Electric double layer, Graphite fibers
- Format
- Document (PDF)
- Title
- THE DESIGN OF SWITCHED-CAPACITOR HIGHPASS FILTERS.
- Creator
- LEE, KING FU., Florida Atlantic University, Gazourian, Martin G., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The design of high order switched-capacitor highpass filters is presented. Emphasis is placed on the design procedures of cascaded biquadratic sections and ladder network realizations of switchedcapacitor highpass filters. The stability problem of the doubly terminated switched-capacitor ladder highpass filter is discussed. Design examples are presented to illustrate the design procedures. The sensitivities of the realization methods are discussed. An .analytical equation of the gain...
Show moreThe design of high order switched-capacitor highpass filters is presented. Emphasis is placed on the design procedures of cascaded biquadratic sections and ladder network realizations of switchedcapacitor highpass filters. The stability problem of the doubly terminated switched-capacitor ladder highpass filter is discussed. Design examples are presented to illustrate the design procedures. The sensitivities of the realization methods are discussed. An .analytical equation of the gain deviation for the cascaded biquadratic sections realization is derived. Monte Carlo analysis is performed for the design examples. The results of the analyses are compared to reveal the differences in sensitivities in terms of the order of the filters and the type of realizations.
Show less - Date Issued
- 1983
- PURL
- http://purl.flvc.org/fcla/dt/14169
- Subject Headings
- Switched capacitor circuits, Digital filters (Mathematics)
- Format
- Document (PDF)
- Title
- CVD synthesis of carbon nanotubes as active materials for electrochemical capacitors.
- Creator
- Merritt, Ryan Patrick., Florida Atlantic University, Lipka, Stephen M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Results are reported on a method to synthesize multi-wall carbon Nanotubes (MWNTs) using a liquid injection chemical vapor deposition (CVD) method centered around ferrocene as the catalyst precursor. These materials were specifically targeted as active materials for electrochemical double layer capacitors (EDLCs). A parameteric study was developed to optimize material synthesis based on growth parameters, characterize physical growth properties, and evaluate the performance of the MWNTs as...
Show moreResults are reported on a method to synthesize multi-wall carbon Nanotubes (MWNTs) using a liquid injection chemical vapor deposition (CVD) method centered around ferrocene as the catalyst precursor. These materials were specifically targeted as active materials for electrochemical double layer capacitors (EDLCs). A parameteric study was developed to optimize material synthesis based on growth parameters, characterize physical growth properties, and evaluate the performance of the MWNTs as electrodes in electrochemical capacitors. Physical data includes scanning electron micrographs (SEM), transmission electron micrographs (TEM), and x-ray powder diffraction (XRD). Electrochemical performance data is given based on cyclic voltammetry (CV) and impedance spectroscopy (EIS).
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/13037
- Subject Headings
- Chemical vapor deposition, Electric double layer, Electrolytic capacitors, Nanotubes
- Format
- Document (PDF)
- Title
- Modeling and analysis of aluminum/air fuel cell.
- Creator
- Leon, Armando J., Zilouchian, Ali, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The technical and scientific challenges to provide reliable sources energy for US and global economy are enormous tasks, and especially so when combined with strategic and recent economic concerns of the last five years. It is clear that as part of the mix of energy sources necessary to deal with these challenges, fuel cells technology will play critical or even a central role. The US Department of Energy, as well as a number of the national laboratories and academic institutions have been...
Show moreThe technical and scientific challenges to provide reliable sources energy for US and global economy are enormous tasks, and especially so when combined with strategic and recent economic concerns of the last five years. It is clear that as part of the mix of energy sources necessary to deal with these challenges, fuel cells technology will play critical or even a central role. The US Department of Energy, as well as a number of the national laboratories and academic institutions have been aware of the importance such technology for some time. Recently, car manufacturers, transportation experts, and even utilities are paying attention to this vital source of energy for the future. In this thesis, a review of the main fuel cell technologies is presented with the focus on the modeling, and control of one particular and promising fuel cell technology, aluminum air fuel cells. The basic principles of this fuel cell technology are presented. A major part of the study consists of a description of the electrochemistry of the process, modeling, and simulations of aluminum air FC using Matlab Simulink™. The controller design of the proposed model is also presented. In sequel, a power management unit is designed and analyzed as an alternative source of power. Thus, the system commutes between the fuel cell output and the alternative power source in order to fulfill a changing power load demand. Finally, a cost analysis and assessment of this technology for portable devices, conclusions and future recommendations are presented.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fau/fd/FA0004032
- Subject Headings
- Biomass energy, Electrocatalysis, Electrolytic capacitors -- Materials, Fuel cells -- Materials, MATLAB, Nanostructured materials, Renewable energy sources
- Format
- Document (PDF)
