Power and Energy Commons^™

Characterization Of Hardening By Design Techniques On Commercial, Small Feature Sized Field-Programmable Gate Arrays, Thomas E. Simmons

Theses and Dissertations

In this thesis, a methodology is developed to experimentally test and evaluate a programmable logic device unde r gamma irradiation. The purpose of which is to determine the radiation effects and characterize the improvements of various hardening by design techniques. The techniques analyzed in this thesis include Error Correction Coding (ECC) and Triple Modular Redundancy (TMR). The TMR circuit includes three different functional implementations of adders compared to TMR voted circuits of those same adders. The TMR is implemented with the same functional adders and as a Functional TMR (FTMR) with three different function adders that are voted on. The …

Characterizing The Exhaust Plume Of The Three-Electrode Micro Pulsed Plasma Thrusters, Myeongkyo Seo

Theses and Dissertations

Three-electrode micro-PPTs are a new version of two electrode micro-PPTs devices. Performance predictions and contamination expectations are essential characteristics needed by satellite designers. In order to focus on thruster specific impulse, thrust and efficiency, measuring the exhaust velocity or impulse bit and propellant consumption rate is essential. While this is not always possible to measure directly, focusing on the ejected mass from the PPT provides significant information allowing determination of these performance statistics. Specifically, focusing on exhaust angle distribution and velocity of the exhaust particles is the emphasis of this work. The results show that the three-electrode micro-PPT is more …

Optimized Robust Adaptive Networks In Supervisory Control And Data Acquisition Systems, Luis A. Oquendo Class

Theses and Dissertations

This thesis investigates the application of a Exponential Weighted Moving Average (EWMA) to be used as a memory buffer in conjunction with Special Protection Schemes (SPS) using the Electric Power and Communication Synchronizing Simulator (EPOCHS). It is proposed that using an SPS incorporating EWMA can compensate for the network layer lack of guarantee of packet delivery and provide for the stability and integrity of the power grid under a catastrophic event. The performance of the proposed SPS is evaluated using a discrete event computer simulation developed using the NS2 network simulator and the Power System Simulator for Engineering (PSS/E) power …

Examination Of The Regional Supply And Demand Balance For Renewable Electricity In The United States Through 2015, Lori Bird, David Hurlbut, Pearl Donohoo, Karlynn Cory, Claire Kreycik

Publications (E)

This report examines the balance between the demand and supply of new renewable electricity in the United States on a regional basis through 2015. It expands on a 2007 NREL study (Swezey et al. 2007) that assessed the supplynational basis. As with the earlier study, this analysis relies on estimates of renewable energy supplies compared to demand for renewable energy generation needed to meet existing state renewable portfolio standard (RPS) policies in 28 states, as well as demand by consumers who voluntarily purchase renewable energy. However, it does not address demand by utilities that may procure cost-effective renewables through an …

Preparation And Performance Of Co And La Co-Doped Li-Rich Lithium Manganate, Da-Qiao Zhou

Journal of Electrochemistry

The cathode material of Li_1.1Co_0.02La_0.01Mn₂O₄ was successfully synthesized by the method of co-precipitation followed by a solid state reaction.In the sintering temperature range of 700～850 ℃,X-ray diffraction(XRD) results showed a single phase of each material and the increase of crystallization degree,and scanning electron microscopic(SEM) images indicated that the particle size increased and the specific surface area decreased,respectively,with increasing the sintering temperature.Due to its lower polarization resistance,the Co and La co-doped lithium-rich lithium manganate(sintered at 800 ℃) positive electrodes showed the most promising electrochemical performance.The capacity retention after 50 cycles reached 98.5%.

Electrochemical Properties Of Functionalized Carbon Nanotubes And Their Applications In Analysis Of 6-Mercaptopurine, Bao-Yi Lu, Yan-Yan Lai, Hong Li

Journal of Electrochemistry

The electrochemical behaviors and adsorption properties of single-walled carbon nanotubes such as SWNT,SWNT-COOH,and SWNT-OH and multi-walled carbon nanotubes including MWNT,MWNT-COOH,and MWNT-OH modified at a graphite electrode have been investigated by using [Fe(CN)₆]^3-anion and [Co(phen)₃]³⁺ cation.It was shown that shows good redox reversibility of [Fe(CN)₆]^3-/4-reactions on the existed carbon nanotubes(CNT) modified electrode.Based on the strong adsorptive property of [Co(phen)₃]³⁺ on the CNT surface,the [Co(phen)₃]³⁺/CNT modified graphite electrode can be obtained by progressive potential sweeping and developed to monitor quantitatively 6-mercaptopurine(6-MP).The adsorption capacity of …

High Utilization Aupt Nanoparticles Supported On Mwcnts For Methanol Electro-Oxidation In Alkaline Medium, Xun Guo, Dao-Jun Guo, Xin-Ping Qiu, Li-Quan Chen, Wen-Tao Zhu

Journal of Electrochemistry

We synthesized gold-platinum electrocatalysts supported on multi-walled carbon nanotubes(MWCNTs) with high utilization by a simple one-step method.A high Pt loading series of bimetallic AuPt/MWCNTs catalysts were prepared by the improved ethylene glycol reduction method,and then were compared in terms of the electrocatalytic activity for methanol electro-oxidation using cyclic voltammetry(CV) and chronoamperometry in alkaline solutions.The structure of AuPt/MWCNTs was characterized by the transmission electron microscopy(TEM),X-ray diffraction(XRD) and energy-dispersive X-ray spectroscopy(EDS).The results showed that the AuPt/MWCNTs catalysts had high Pt utilization,uniform AuPt nanoparticles size and good electrocatalytic activity for methanol electro-oxidation.The effect of Au/Pt mass ratio on electrocatalytic activity was also investigated.The …

Preparation And Electrochemical Performance Of Li3V2(Po4)3, Hou-Gang Fan, Tao Jiang, Chun-Zhong Wang, Gang Chen, Ying-Jin Wei

Journal of Electrochemistry

The carbon coating Li₃V₂(PO₄)₃ powder samples were synthesized by carbon incorporation solid state reaction.The structure,morphology and electrochemical properties have been studied by X-ray powder diffraction,scanning electron microscopy and automatic battery tester system,respectively.Carbon coating on Li₃V₂(PO₄)₃ would prevent the particles from agglomerating,reduce the particle size,raise the conductivity and improve the samples′ electrochemical performance.

Silicon Nanowires As Anode Materials For Lithium Ion Batteries, Yan-Peng Fu, Hui-Xin Chen, Yong Yang

Journal of Electrochemistry

The SiNWs electrodes were fabricated by coating and direct growth methods,respectively.The structure,morphology and electrochemical performance of such materials were characterized by XRD,SEM and charge-discharge tests.The results show that the electrodes prepared by direct growth method had higher capacity,better battery life and also displayed and excellent cyclability at higher currents.During the process of lithiation,the initial crystalline Si transformed to amorphous LixSi,and the average diameter of the SiNWs increased.Despite the large volume changed,the SiNWs remained intact and did not break into smaller particles.

Electrocatalytic Reduction Of Oxygen On Tungsten Carbide Electrode, Chun-An Ma, Yun Huang, Ying-Hong Zhu, Zhao-Yang Chen

Journal of Electrochemistry

Tungsten carbide(WC) catalysts were prepared by gas-solid reaction using ammonium metatungstate as precursors which were pretreated with spray drying sphere miniaturation,carbon monoxide as carrier gas and hydrogen as deoxidizing gas.The WC electrode was fabricated using WC catalyst powders and PTFE as binding agent,and characterized by XRD and SEM.Electrocatalyst behavior of WC for oxygen reduction reaction in the sulphuric acid solution was studied by steady-state voltammetry and cyclic voltammetry.The results show that the WC powders obtained were in spheric particles and the prepared WC electrode had a good electrocatalyst activity to the oxygen reduction reaction.The electrode reaction was controlled by adsorption.The …

Nano-Sn/Hard Carbon Composite As Anode Material For Lithium Ion Batteries, Bing-Kun Guo, Jie Shu, Kun Tang, Ying Bai, Zhao-Xiang Wang, Li-Quan Chen

Journal of Electrochemistry

The tin(Sn) nano particles were embedded into the mesopores of hard carbon spherules(HCS) to form a composite anode material for lithium ion batteries.The structure of the obtained composite was characterized by X-ray diffraction(XRD) while its electrochemical performances were evaluated with galvanostatic cycling.It is found that the embedding Sn nanoparticles into porous HCS not only result in a composite material with high lithium storage capacity and capacity retention,but also increase the initial coulombic efficiency of the composite.Based on the infrared spectroscopic analysis,the enhanced initial coulombic efficiency is attributed to the inductive decomposition of the ROCO₂Li species in the solid …

19th International Symposium Of Fine Chemistry And Functional Polymers (Fcfp-Xix) & Iupac 5th Internaitonal Symoposium On Novel Materials And Synthesis (Nms-V), Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Preparation Of The Protic Ionic Liquid/Pvdf-Hfp Composite Membranes And Its Performance For Dmfc, Rui-Ying Miao, Jian-Ling Li, Yong Fang, Xin-Dong Wang

Journal of Electrochemistry

The protic ionic liquid(PIL) α-methyl pyridinium trifluoroacetate([α-MPyH]Tfa) was synthesized by acid & alkali neutralization.Then PIL/PVDF-HFP composite membranes were prepared by means of phase inversion method using acetone as solvent.The conductivities of the composite membrane increased with the temperature and reached 8×10^-3 S/cm,1×10^-2 S/cm and 3×10^-2 S/cm at room-temperature,30 ℃ and 80 ℃,respectively,by electrochemical impedance method.The properties of the methanol-rejecting of the membranes were measured by chronoamperometry as well.The results indicate that the properties of methanol-resistance of the membranes before and after IL combination were equivalent approximately.

Mesoporous Carbon For High Power Supercapacitors, Bin Xu, Lu Peng, Guo-Qing Wang, Gao-Ping Cao, Feng Wu, Yu-Sheng Yang

Journal of Electrochemistry

Mesoporous carbon for supercapacitors was prepared from sucrose using nano-CaCO₃ as template.The microstructure of the carbon was characterized with N₂ adsorption and transmission electron microscopy(TEM) observation.The electrochemical performances were evaluated in 6mol·L^-1 KOH aqueous electrolyte with galvanostatic charge/discharge,cyclic voltammetry,and ac impedance spectroscopy.The sucrose-based mesoporous carbon had a surface area of 606 m²/g and enriched mesopores in the range of 10～30 nm.The mesoporous carbon presented a specific capacitance of 125 F/g at a current density of 50 mA/g and outstanding excellent rate performance.As the current density increased to 20 000 mA/g,its capacitance remained at 88 F/g,much …

Preparation And Performance Of The Thin-Film Libpon Electrolyte, Feng Wu, Ya-Dong Liu, Ren-Jie Chen, Shi Chen

Journal of Electrochemistry

The LiBPON thin-film electrolyte was prepared by magnetron sputtering,and the relationship between the performance and the deposition condition was investigated.As seen in the SEM images,the thin films are dense and uniform without cracks,and according to the XRD patterns they have an amorphous structure.The electrochemical performance of the electrolyte was characterized by electrochemical impedance spectroscopy(EIS).The ionic conductivities of the thin film decreased with the RF power,but increased with the N₂ pressure.The an ionic conductivity of 3.5×10^-6 S/cm at room temperature was found from the electrochemical measurement.While the deposition rate increased with the RF power,but decreased with the N_{2 …}

Photoelectrochemical Properties Of Tio2 Nanoparticles, Jie Qu, Ying Li, Qi-Wei Jiang, Xue-Ping Gao

Journal of Electrochemistry

The protonated titanate nanoparticles were obtained at room temperature and subsequently calcined at different temperatures(300 ℃,400 ℃,500 ℃,600 ℃ and 700 ℃) in air.The obtained products were characterized by XRD,TEM and UV-Vis.It is found that the grain sizes of TiO₂ nanoparticles calcined at 300 ℃ were about 20 nm,and increased gradually with the temperature rise.Photoelectric performance was measured with I～V curve and electrochemical impedance spectroscopy(EIS).The TiO₂ nanoparticles obtained at 500 ℃ showed the best photoelectrochemical properties with a photovoltaic conversion efficiency of 6.39%,which is much higher than those at other temperatures.In addition,it is also demonstrated that the charge …

Electrooxidation Behaviors Of Tib2 As High Capacity Anodic Material In Neutral Aqueous Electrolytes, Ya-Dong Wang, Xian-Yong Guang, Zhi-Xin Wang, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

Titanium diborides were investigated as an anodic material for neutral aqueous batteries. It is revealed that this material shows superiorly high electrochemical activities in the neutral electrolytes. The discharge capacities observed for TiB₂ reached 1300 mAh/g at the constant current density of 50 mA/g, exceeding all the metal electrodes reported so far. The electrooxidation of this compound was found to proceed via the electrochemical dissolution of boron to form borofluoride, while titanium remained unchanged at the electrode. These results suggest a possible use of the boride compounds as a new material for constructing neutral aqueous batteries with high electrochemical …

The Electrochemical Performance Of Ncf-Sulfur Cathode, Chun-Rong Zhao, Zhong-Bao Yu, Wei-Kun Wang, Yu-Sheng Yang

Journal of Electrochemistry

The electrochemical performance of NCF-sulfur cathode, with different NCF contents, was investigated by constant current discharge, cyclic voltammetry and AC impedance methods. The morphologies of the cathodes were observed using scanning electron microscopy. The results indicate that the cycle life and rate capability of NCF-sulfur cathode increased. Better performance of sulfur cathode was obtained by 3% and 5% NCF conductive addition. When the current density was 0.4 mA/cm², the 3% NCF-sulfur cathode had an initial capacity of 880 mAh/g and a reversible capacity of 630 mAh/g after 20 cycles.

Electrosynthesis Of 2,2-Dimethylolpropionic Acid, Hong-Yan Sun, Zhen-Hai Liang

Journal of Electrochemistry

The Ti/SnO₂+Sb₂O₄/PbO₂ electrode was prepared.The structure phase and valent state were characterized by means of XRD and XPS.The 2,2-dimethylolpropionic acid was synthesized on the Ti/SnO₂+Sb₂O₄/PbO₂ anode by direct electro-oxidation of 2,2-dimethylolpropionaldehyde.The product and crude material were analyzed by HPLC,the effects of the concentration of 2,2-dimethylolpropionaldehyde,pH,potential and reaction temperature were studied.The results showed that the optimum conditions were anode potential 1.8 V,pH=1,reaction temperature 15 ℃ and 2,2-dimethylolpropionaldehyde concentration 0.10mol/L.Under the optimum conditions,the selectivity of 36%,the current efficiency of 28% and the conversion of 58% were reached.The reported …

Voltage Delay On Li/Socl2 And Bcx Cells During Discharge, Shu-Tao Liu, Yi-Ping Wu, Hong-Hua Ge, Guo-Ding Zhou

Journal of Electrochemistry

The impedance change of both lithium and carbon electrodes during the process of discharge was studied by AC impedance spectroscopy.It shows that the impedance of lithium electrode at initial stage was reduced by 80%～90% and kept nearly unchanged after wards;the carbon electrode impedance initially did not change much but quickly increased just before the end of discharge.The improvement of voltage delay might be related with the higher open-circuit voltage of BCX cell.It is suggested that the voltage delay problem may be solved by the application of supercapacitor.

Synthesis,Characteristics And Electrochemical Performance Of Nano-Sized Snco/Graphite Composites As Anode For Lithium Ion Batteries, Jin-Shu Cai, Ling Huang, Fu-Sheng Ke, Shi-Gang Sun

Journal of Electrochemistry

The nano-structural Sn-Co/graphite composites were prepared by chemical reduction of the alloy electroless deposition solution in graphite suspensions, and the composites were annealed at 500 ℃. The phase structure and surface morphology of the composites were measured by XRD, SEM and Raman. The results indicate that there were high dispersions and high loadings of Sn-Co nanoparticles on graphite by thermal treatment. Electrochemical lithium storage performance was studied preliminarily on the obtained samples. The graphite modified with the Sn-Co nanoparticles possessed a higher electrochemical reversible capacity than that of graphite during the charge and discharge process. The appetency between the Sn-Co …

Power Generation By Harvesting Ambient Energy With A Micro-Electromagnetic Generator, James H. Shields

Theses and Dissertations

This thesis investigated the potential power output of a micro-electromagnetic generator fabricated using typical microfabrication materials and techniques. The design was based on a desire to free bio-implanted or remote electronic devices from batteries and their finite power supplies. A micro-electromagnetic generator could harvest energy from the ambient environment and power such devices indefinitely. Designs for the stator coil and rotor magnet components of the generator were optimized to produce maximum current density based upon electromagnetic theory. The relative orientation of the coil to the rotor and material selection for each component were considered. Coils were fabricated using low-resistance gold. …

Fabrication Of Silicon Photovoltaic Micro-Particles For Low-Cost Solar Energy Generation, Siddhartha Kala

Electronic Theses and Dissertations

The relatively high cost of the high quality semiconductor materials (typically silicon) and complex conventional techniques for the fabrication of solar cells result in the overall high cost of the commercially available solar cells. Although, research in the field of solar technologies has been going on for a long time, but, utilization of solar energy still remains limited to a very few applications, owing to the high manufacturing costs and lower efficiency. In this work we present a new solar technology based on silicon photovoltaic micro-particles and demonstrate a fabrication technique for such particles. The photovoltaic micro-particles can be manufactured …

The Solar Transformity Of Petroleum Fuels, S. Bastianoni, D. E. Campbell, R. Ridolfi, F. M. Pulselli

United States Environmental Protection Agency: Publications

Petroleum fuels are the primary energy basis for transportation and industry. They are almost always an important input to the economic and social activities of humanity. Emergy analyses require accurate estimates with specified uncertainty for the transformities of major energy and material inputs to economic and environmental systems. In this study, the oil refining processes in Italy and the United States were examined to estimate the transformity and specific emergy of petroleum derivatives. Based on our assumptions that petroleum derivatives are splits of a complex hydrocarbon mixture and that the emergy is split based on the fraction of energy in …

Energy From The Skies: Empowering Future Generations, Petros J. Katsioloudis, Stella Bondi, Walter F. Deal

STEMPS Faculty Publications

The article discusses the development of photovoltaic technology. The first account of the use of solar power during war in western civilization was in the second century B.C. during the battle of Syracuse with Archimedes' famed Death Ray. In the late 1800s and early 1900s many advances occurred including the invention of solar-powered engines, the discovery of the photoconductivity of selenium and its ability to produce electricity when exposed to light, and the construction of the first solar cells from selenium wafers. Photovoltaic technology was born in the U.S. in 1954 when Daryl Chapin, Calvin Fuller, and Gerald Pearson developed …

Islanded Operation Of A Distribution Feeder With Distributed Generation, Chandu Venu

UNLV Theses, Dissertations, Professional Papers, and Capstones

A distribution system that is equipped with distributed generators, such as roof-mounted photovoltaic systems, can operate as a microgrid (i.e., separated from the grid) under some specific conditions. A key feature of a microgrid is its ability to separate and isolate itself from the utility seamlessly with little or no disruption to the loads within the microgrid. Then, when the utility grid returns to normal, the microgrid automatically resynchronizes and reconnects itself to the grid, in an equally seamless manner. This thesis addresses the conditions necessary for proper microgrid operation: these include local generation-load mismatch, local energy storage, load switching, …

Engineering Of A Single Alkaline Fuel Cell Part Ii: Long Term Operation In Air, Jonathan Blackledge, Eugene Coyle, David Kennedy, Heinz Schmidt-Walter, Hans Kohnke, Steffen Schudt, Gerhard Sauer, James Hamilton

Articles

Research into renewable energy sources has previously lacked sufficient investment. However, emphasis has now shifted and funding is being made available in a proactive manner by various governments eager to encourage renewable energy technology and reduce carbon taxes. Fuel Cells offer a realistic, sustainable and clean alternative energy option for stationary and mobile applications. Hydrogen and fuel cell technologies are recognised by many as possible long term energy solutions, but to-date, have failed to make an impact on the energy market. This is due to a number of key reasons, some of which include efficiency, scale, accessories and power output. …

Engineering Of A Single Alkaline Fuel Cell Part I: Construction Of A Test Bed, Jonathan Blackledge, James Brunton, Eugene Coyle, David Kennedy, Heinz Schmidt-Walter, Hans Kohnke, Gerhard Sauer, Steffen Schudt, James Hamilton

Articles

Fuel Cells offer a realistic, sustainable and clean alternative energy option for stationary and mobile applications. Hydrogen and fuel cell technologies are recognised by many as possible long term energy solutions, but to-date have failed to make an impact on the energy market. This is due to a number of key reasons, some of which include, efficiency, scale, accessories and power output. Applying fuel cells to small telecommunication components requires the applications of Micro and Nanotechnology, which have yet to be perfected to make them long lasting and cost effective. This paper outlines the reasons for commercialisation of fuel cells …

Analysis And Design Of Continuous Input Current Multiphase Interleaved Buck Converter, Sean Michael Zich

Master's Theses

The power requirements for microprocessors have been increasing per Moore's Law. According to International Technology Roadmap (ITRS), Voltage Regulator Module (VRM) for microprocessors will be about 200 W at 1 V output in 2010. With the VRM’s topology of synchronous buck, serious technical challenges such as small duty cycle, high switching frequencies, and higher current demands, contribute to decreased power density and increased cost.

This thesis proposes a Continuous Input Current Multiphase Interleaved Buck topology to solve the technical challenges of powering future microprocessors. This new topology is aimed to improve past topologies by providing continuous input current and improved …

Spectroscopic Investigation Of Palladium-Copper Bimetallic Systems For Pem Fuel Cell Catalysts, Timo Hofmann

UNLV Theses, Dissertations, Professional Papers, and Capstones

One of the main barriers to commercialization of polymer electrolyte membrane fuel cells systems is cost, which is largely due to the need of platinum (Pt)-containing catalysts. In this thesis we investigate bimetallic systems consisting of a base metal (copper) and a noble metal (palladium) that, as an alloy on the nanoscale, mimic the electronic properties that make Pt desirable as a catalyst.

We present a detailed investigation of the electronic structure of carbon-supported Pd/Cu nanoparticle catalysts, model bilayer thin film systems, alloys, and various metal reference samples. We have investigated the valence band structure of the catalysts using a …