Power and Energy Commons^™

Study Of Secondary Electron Emission From Niobium At Cryogenic Temperatures, Anoop George

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this project is to study the properties of secondary electron emission from niobium samples, cleaned at the Los Alamos National Laboratory, at cryogenic temperatures to enhance existing multipacting codes with data on the samples. The predominant cause of power loss in radio-frequency superconducting accelerators cavities is multipacting. This project studies the secondary electron distribution from niobium metal due to incident primary electrons. The experiments on the niobium sample are performed in an environment close to that present in a superconducting accelerator cavity.

The experiment is performed in a vacuum chamber capable of achieving ultra high vacuum levels …

Application Of Nickel Foam Electrode For Electroreduction Intermediate Of Purine, Hui-Wen Yang, Xi-En Hu, Xue-Jun Wang

Journal of Electrochemistry

Nickel foam with weight uniformity, good porosity ,pore size and low resistivity as a three-dimensional cathode was used in a filter-press electrochemical reactor. The H₂SO₄ as supporting electrolyte, separator of cation ion exchange membrane, and the lead plate as an anode were used. The cyclic system consisted of electroreduction reactor, pump, store tank and ampere meter. NAU was electroreduced in the cathode chamber of the reactor. Purine intermediate was synthesized with DAU, and the results were compared with those of iron powder reduction process. A peak current in the electroreduction process was detected. The current density of …

A Preliminary Study Of Electrocrystallization Of Bismuth On Glassy Carbon, Min-Li Yang, Zhan-Jun Zhang

Journal of Electrochemistry

The electrocrystallization of bismuth on glassy carbon electrodes (GCEs) from nitrate solutions was studied by cyclic voltammetry and chronoamperometry. Cyclic voltammograms exhibit a crossover between the cathodic and anodic branches, characteristic of the formation of bismuth nuclei on GCEs, and show that the bismuth electrocrystallization on GCEs is a diffusion-controlled reaction. The current transients were analyzed with the Scharifker and the Heerman equations. With the increaseof Bi³⁺ concentration, the non-dimensional plots leaned to the theoretical curve for 3D instantaneous nucleation and growth. The overpotential dependence of nucleation and growth mechanism was also found. With the increase of overpotential, the …

Preparation And Characterization Of Mcm-41/Pvdf-Hfp Composite Microporous Polymer Electrolytes For Li-Ion Batteries, Zuo-Feng Chen, Yan-Xia Jiang, Quan-Chao Zhuang, Quan-Feng Dong, Shi-Gang Sun

Journal of Electrochemistry

MCM-41/vinylidine fluoride-hexafluropropene copolymer (PVdF-HFP) composite microporous polymer electrolytes were prepared with mixed solvent of N, N-Dimethylformamide (DMF) and acetone. The influence of MCM-41 and nano-SiO₂ on the porous structure of the microporous polymer electrolytes were studied with SEM. The results show that MCM-41 could take the place of the plasticizer in the process of making pores, and bring the preparation of microporous membranes easily. The preliminary electrochemical tests showed that the ion conductivity of composite microporous polymer electrolyte with 10% MCM-41 was about 10^-3 S cm^-1, and the performance of batteries was improved. The mesoporous MCM-41selected …

Investigation On Ru-Ti-Ir-Sn Oxide Anode Coatings For Electrolyzing Seawater, Ke Wang, Yan Han, Lei-Yuan Wang, Xiao-Ling Zhang, Yu-Pu Sun

Journal of Electrochemistry

The anode coatings of Ru-Ti-Ir-Sn oxide with various compositions were prepared by thermal decomposition. The physical and electrochemical properties of the coatings were characterized by scanning electron microscope (SEM), energy dispersive X-ray detector (EDX), accelerated life, current efficiency, anti-Mn²⁺ contamination, polarization curveandcyclic voltammetry tests. The results showed thatthe anode coating with optimized formula possessed excellent overall properties for electrolyzing seawater.

Study On Synthesis Of M-Phenoxy Benzoic Acid By Electrolysis Oxidation Method, Wei Xu, Chong-Tao Zhao

Journal of Electrochemistry

The m-phenoxy benzoic acid was synthesized by oxidation m-phenoxy toluene using Cr(Ⅵ)as oxidation media, which was prepared by electrolysis oxidation of Cr(Ⅲ)in the electrochemical bath using Nafion 417 as a diaphragm, Pb-PbO₂ as an anode and Pb as cathode. The effect factors on the electrochemical oxidation of Cr(Ⅲ)to Cr(Ⅵ)in this electrolysis were studied. Furthermore, the optimal conditions for electronic synthesis of m-phenoxy benzoic acid were also discussed.

The Preparation And Performance Of The Aqueous Matrix For Molten Carbonate Fuel Cells, Hua-Xin Lin, Mo-Jie Ceng, Bao-Lian Yi

Journal of Electrochemistry

PVA matrix of MCFC was prepared from the α-LiAlO₂ powder, and polyvinylalcohol(PVA), Compared with the conventional PVB matrix, higher porosity, higher thermal weight loss and smaller maximum pore diameter were achieved for PVA matrix. Single cell was assembled with PVA matrix. At reaction gas pressure of 0.9 MPa, under reaction gas utilization of 20%, at 300 and 428.57 mA·cm^-2, the cell voltage was 0.849 and 0.739 V respectively, and the output power density was 254.7 and 316.7 mW·cm^-2 respectively, which are higher than those of the cell assembled with PVB matrix. During thermal cycles, the cell …

The Synthesis, Characteristics And Performance Of Cnt Composites As Anodic Materials In Litium-Ion Battery, Quan-Feng Dong, Ming-Sen Zheng, Zhen-Cai Huang, Ming-Gang Jin, Ya-Ding Zhan, Zu-Geng Lin

Journal of Electrochemistry

As an anodic material for lithium ion battery the carbon nano-tube (CNT) and some compounds based on tin have ever been investigated intensively. The fruited progress has not been made yet, however. In this paper the composites of CNT and Sn/SnO₂ were synthesized employing two methods and characterized by SEM and XRD. And the electrochemical performance of the composites was investigated.

The Effect Of Oxidant On Structure And Properties Of Pan/Ptfe Conducting Composite Membrane, Chang-Yuan Tao, Jing Chen, Jun Du, Cai-Xin Sun

Journal of Electrochemistry

The PAn/PTFE conducting composite membrane was prepared by means of in-situ permeating chemical polymerization, with (NH₄)₂S₂O₈ and Na₃VO₄ being used as an oxidant respectively. The polymerization-growth behavior of the aniline by using different oxidant was compared. In addition, the oxidant effect on the structure and properties of conducting composite membrane was discussed. The results of SEM micrographs, pore size distribution and electrochemical methods suggested that using either oxidants could also induce the product with small pore size and dense pore structure. Compared with (NH₄)₂S₂O …

An Evaluation Of Wind Turbine Technology At Peterson Afb, Randy C. Combs

Theses and Dissertations

Wind energy technology is a viable source for attaining the emission reduction and renewable energy use goals set forth by the executive office. In accordance with Executive Orders, the Air Force must reduce greenhouse emissions and energy consumption, and expand the use of renewable energy sources within its facilities nation-wide by year 2010. This mandate requires that the Air Force look at alternative electrical production and rely more on such renewable energy resources as wind power. The specific problem addressed by this research is whether on-site wind energy generation can be more economically feasible than the conventional energy consumption at …

Anodic Polarization Behaviors Of Carbon Steel In Bicarbonate Solution, Jing-Mao Zhao, Yu Zuo

Journal of Electrochemistry

The anodic polarization curves of mild steel were measured in sodium bicarbonate solution of various concentrations, and the surface products were analyzed by XPS. Two anodic current peaks and two passive zones are observed in all the curves. When HCO₃^- ions concentration is below 0.1mol/L, the two peaks are so close that the first passive zone is difficult to be observed. When HCO₃^- ions concentration is above 0.1 mol/L, the first peak appears clear, while the second becomes smaller. The XPS results indicate that the out layer of film formed at a higher potential is mainly …

Preparation And Characterization Of Lini0.85Co0.10(Timg)0.025O2 As Cathode Materials For Lithium-Ion Batteries, Xian-Jun Zhu, Hong-Hao Chen, Hui Zhan, Dai-Ling Yang, Yun-Hong Zhou

Journal of Electrochemistry

Cathode material of LiNi_0.85Co_0.10(TiMg)_0.025O₂ were prepared by solid state reaction at 725℃ for 24 h from LiOH·H₂O, Ni₂O₃, Co₂O₃, TiO₂ and Mg(OH)₂ under flowing oxygen, and were characterized by TG-DTA, XRD, SEM and electrochemical tests. Effort to simultaneously doped LiNiO₂ with Co-Ti-Mg has been tried to improve the cathode performance. The results show that co-doping definitely has a large beneficial effect in increasing the capacity (182.7mAh/g of the first discharge capacity for  LiNi_0.85Co_0.10(TiMg)_0.025O_{2 …}

Studies On Polymer Light-Emitting Electrochemical Cells ——Introduction Of The Studies On The Electrochemistry Of Conducting Polymers In Cas Key Laboratory Of Organic Solids (Ⅱ), Yong-Fang Li

Journal of Electrochemistry

Polymer light-emitting electrochemical cell (LEC) is composed of a conjugated polymer(CP)/polymer electrolyte blend film sandwiched between an ITO anode and an Al cathode. When a bias voltage greater than Eg/e (where Eg is the energy gap of the CP, e is the electron charge) is applied on the two electrodes, the CP in the polymer blend film at the anode side will be oxidized (to form a p-doped region), and that at the cathode side will be reduced (to form a n-doped region), then a p-i-n junction will be produced. Light-emission occurs in the intrinsic region between the p- and …

A Study Of Metal Borides As High Capacity Anode Materials For Aqueous Primary Batteries, Ya-Dong Wang, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

The transition metal borides VB₂ and TiB₂ were tested as high capacity anode materials and their electrochemical behaviors were studied by cyclic voltammetry and discharge measurements. The experimental results indicated that transition metal borides VB₂ and TiB₂ electrodes can deliver exceptionally high discharge capacity of over 3100 mAh/g and 1 600 mAh/g respectively, corresponding to 11- and 6-electron oxidation reaction, although their parent elements V, Ti and boron, are almost completely electrochemically inert. The different electrochemical activitis were probably due to the electrochemical activation of boron, which clamp the potential to passivation for Ti and activity …

Application Of Carbon Paste Electrode On The Electrogenerative-Leaching Process Of Sulfide Minerals, Shao-Fen Wang, Zheng Fang, Yun-Yan Wang

Journal of Electrochemistry

The cyclic voltammetry curves of sulfide mineral electrodes or corresponding carbon paste electrodes in NaCl electrolytes have been obtained in this study. The experimental results indicate that acetylene black (revealed) the electro-catalytic propertyin the electrogenerative-leaching process of sulfide minerals. The output currentand potential of carbon paste electrodes were increased to some degrees while the activation energies were lower.

Preparation Of Poly (Bromophenol Blue) Modified Glassy Carbon Electrode And Its Electrocatalytic Activity, Wei Chen, Hong-Bin Luo, Xin-Hua Lin

Journal of Electrochemistry

A film of poly (bromophenol blue) was formed on a glassy carbon electrode by using cyclic voltammetry. A stable film could be obtained with a potential range from -1.0 V to +1.8 V (vs.Ag/AgCl). The experimental results showed that the poly (bromophenol blue) modified glassy carbon electrode could catalyse the oxidation of ascorbic acid. It decreased the oxidation potential by about 270mV but increased the peak current. Meanwhile, this electrode showed a good linear current response for the ascorbic acid range from 2.5 to 250 (g/mL).

Research On Phenol Wastewater Treatment By Electrochemical Oxidation, Tian-Cheng Li, Shen-Lin Zhu

Journal of Electrochemistry

Electrochemical oxidation is an effective technology for the phenol wastewater treatment, and the anode properties are important to the electrochemical oxidationefficiency. The over-potentials of oxygen evolution have been measured for thestainless steel, feasible graphite and SnO₂/Ti anode respectively. Moreover, the synthetic phenol wastewater was treated by the electrochemical oxidation with the stainless steel or feasible graphite anodes. The experimental results showed that the order of the over-potential is SnO₂/Ti > graphite > stainless steel; meanwhile, the COD values of purified water were approaching to or less than 100 mg·L^-1, and the phenol concentrations in the purified …

Influence Of Rare Earth Oxide On The Performance Of Secondary Zinc Electrodes, Xian-Ling Meng, Hua-Bin Yang, Jun-Hong Wang, Zuo-Xiang Zhou

Journal of Electrochemistry

Influence of La(OH)₃ or Ce(OH)₃ in secondary zinc electrode was investigated by the cyclic voltammetry, potentiodynamic polarizationand potentiostatic polarization tests and influence of La₂O₃ or CeO₂ in the charge/discharge performance of Zn/Ni battery was studied by galvanostatic charge/discharge experiment. The results showed that the film of rare earth hydroxide prevented the zincate species from transferring toward solution, enhanced hydrogen overpotential and decreased thecorrosion current density (i_corr), and therefore inhibited zinc corrosion. The potentiostatic polarization results at100mV overpotential showed that La(OH)₃ or Ce(OH)₃ oated on the zinc electrode effectively suppressed the …

The Fabrication And Electrochemical Studies On Carbon Nanotube Array Electrodes, Quan-Yong Gao, Jing Zhang, Yong Yang

Journal of Electrochemistry

An improved technique for fabrication of carbon nanotube array electrodes has been proposed in this work. Firstly, carbon nanotubes (CNs) array electrodes were prepared by combsination of Chemical Vapor Decomposition (CVD) method and sputtering techniques in anodized aluminum oxide (AAO) membrane. The CNs/AAO was immersed into HF solution to remove the barrier layer. Controlling the immersing time, the CNs array electrodes with different length contacted with electrolyte can be prepared. The morphology of CNs array electrodes was observed by SEM. The electrochemical properties of CNs array electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Cyclic voltammetric curves of …

Operation Of High-Voltage Transverse Shock Wave Ferromagnetic Generator In The Open Circuit And Charging Modes, Sergey I. Shkuratov, Evgueni F. Talantsev, Jason Baird, Larry L. Altgilbers, Allen H. Stults, Stanislav V. Kolossenok

Mining Engineering Faculty Research & Creative Works

Results of the investigation of the operation of explosive-driven high-voltage shock wave ferromagnetic generators (FMGs) in the open circuit and charging modes are presented. FMGs are based on the transverse (when the shock wave propagates across the magnetization vector M) shock demagnetization of Nd2Fe14B hard ferromagnetic energy-carrying elements of diameter 2.22 cm and length 2.54 cm (volume 8.5 cm3). In the charging mode the capacitance of capacitor banks compatt was varied from 18 to 36 nF. The energy transferred to the capacitor bank reached 0.38 J. FMGs provided pulsed powers of 35-45 kW in times ranging from 10 to 15 …

Microbubble-Based Model Analysis Of Liquid Breakdown Initiation By A Submicrosecond Pulse, J. Qian, R. P. Joshi, K. H. Schoenbach, J. Dickens, A. Neuber, M. Butcher, M. Cevallos, H. Krompholz, E. Schamiloglu, J. Gaudet

Electrical & Computer Engineering Faculty Publications

An electrical breakdown model for liquids in response to a submicrosecond(∼100ns) voltage pulse is presented, and quantitative evaluations carried out. It is proposed that breakdown is initiated by field emission at the interface of pre-existing microbubbles. Impact ionization within the microbubble gas then contributes to plasma development, with cathode injection having a delayed and secondary role. Continuous field emission at the streamer tip contributes to filament growth and propagation. This model can adequately explain almost all of the experimentally observed features, including dendritic structures and fluctuations in the prebreakdown current. Two-dimensional, time-dependent simulations have been carried out based on a …

Power Analysis And Optimization Techniques For Energy Efficient Computer Systems, Wissam Chedid, Chansu Yu, Ben Lee

Electrical and Computer Engineering Faculty Publications

Reducing power consumption has become a major challenge in the design and operation of to-day’s computer systems. This chapter describes different techniques addressing this challenge at different levels of system hardware, such as CPU, memory, and internal interconnection network, as well as at different levels of software components, such as compiler, operating system and user applications. These techniques can be broadly categorized into two types: Design time power analysis versus run-time dynamic power management. Mechanisms in the first category use ana-lytical energy models that are integrated into existing simulators to measure the system’s power consumption and thus help engineers to …

2004 Fall Engr333 Final Report On Co-Generation (Section A), Matt Dekam, Chris Wiesehan, Jason Flietstra, Jeremy Hanson, Brian Katerberg, Kevin Palmer, Aaron Svacha, Aaron Buys, Josh Blocker, Matt Vredevoogd, Andrew Huisjen, Thomas Totoe, Andy Vandermoren, Chris Vanroekel

ENGR 333

The goal of the project was to construct a realistic plan to get Calvin off the grid. This means that Calvin would own and operate on-site facilities that generate all the electricity consumed by the campus. Current peak load for the college is approximately three megawatts. Upon completion of the new recreation center and dining hall renovation, future load will climb to roughly five megawatts. As a result, the desired system to remove the college from the grid would provide five megawatts.

2004 Fall Engr333 Final Report On Wind Generation (Section B), Terry Austen, Kristin De Groot, Matt Ooms, Andy Van Noord, Kurt Koubal, Dan Kuiper, Andy Wermel, Ryan Dewall, Eddie Lucas, Dawn Svenkeson

ENGR 333

An energy savings plan for Calvin College has been developed. The plan suggests implementing a small-scale wind turbine pilot program and an energy usage awareness program (Powerful Savings). If implemented, this proposal could save around $6,400 annually with a payback period of 8 years.

2004 Fall Student Seminar, Matt Dekam, Chris Wiesehan, Jason Flietstra, Jeremy Hanson, Brian Katerberg, Kevin Palmer, Aaron Svacha, Aaron Buys, Josh Blocker, Matt Vredevoogd, Andrew Huisjen, Thomas Totoe, Andy Vandermoren, Chris Vanroekel, Terry Austen, Kristin De Groot, Matt Ooms, Andy Van Noord, Kurt Koubal, Dan Kuiper, Andy Wermel, Ryan Dewall, Eddie Lucas, Dawn Svenkeson

ENGR 333

File for student presentation, given by students in the Fall 2004 class of ENGR333.

Electrochemical Behaviours Of Hemoglobin-Ddab-Modified Powder Microelectrode And The Application Of The Powder Microelectrode In Determination Of Nitric Oxide, Zhi-Mou Guo, Huan Liu, Jian Chen, Wen-Ting Zhang

Journal of Electrochemistry

The electrochemical behaviours of DDAB-Hb-PME were studied in this paper. The (apparent) surface concentration of Hb was enhanced greatly by using the powder microelectrode (technique). NO reacts with Hb and absorbs on the surface of the modified carbon powder. Therefore, the output of the electrode was enhanced greatly by employing PME with higher reaction surface (area). The sensitivity of DDAB-Hb-PME is 3.1 mA/μmol·L^-1·cm², which is much larger than the values obtained with the traditional electrodes. The detection limit is 9 nmol·L^-1 and the linear response range is 9～100 nmol·L^-1.

Improvement And Its Mechanism Of Storage Performance Of Ni-Mh Battery, Xiao-Feng Li, Li-Ping Ma, Yu-Wan Lou, Feng Li, Bao-Jia Xia

Journal of Electrochemistry

The storage performance of nickel-metal-hydride (Ni-MH) battery was studied by using galvanostatic charge-discharge and cyclic voltammetry. The experimental results indicated that CoOOH could not be completely restored after its being thoroughly reduced at lower potential, which might weaken electric conduction network in the positive electrode and result in fading of electrochemical properties of Ni-MH battery. Addition of nickel powder as a conductive agent into the positive electrode was beneficial to the capacity recovery after storage.

Electrocatalytic Performances Of Carbon Nanotube Air Electrode For Oxygen Reduction, Feng-Ming Zhao, Chun-An Ma

Journal of Electrochemistry

The air electrodes with different mass ratio of Pt/active carbon or carbon nanotube as catalyst layer material have been prepared. The electrocatalytic performances for oxygen reduction were evaluated by means of polarization curve and electrochemical impedance spectroscopy (EIS). The results disclosed that carbon nanotubes dealt with nitric acid in the catalyst layer had been improved obviously on the electrocatalytic activity. After the surface of carbon nanotube was oxygenated and aggraded with platinum, the catalyst had obviously effects on the electrocatalytic activity. The air electrode with the mass ratio of active carbon to Pt/carbon nanotube in 4∶1 showed better electrocatalytic activity, …

The Investigation Of Bafesi/C Alloy Composite As Anode Materials For Li-Ion Battery, Rui-Xiang Feng, Hua Dong, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

A novel BaFeSi/C composite was prepared by mechanical ball milling, and lithium insertion reactions on the composite electrode were investigated by cyclic voltammetry , charge-discharge measurements, XRD and XPS spectroscopy. It is demonstrated that the capacity retention with indiscernible capacity decas during charge-discharge cycling. The improved cycling ability of the composite is suggested from a cooperative action by inactive FeSi₂ and BaSi₂ matrix and outer graphite shell, which both buffer the volumetric changes of the active Si phase and provide a good connection for electronic and ionic conduction during lithium insertion and extraction processes.

LicoXNi1-XO2 Cathode Materials Prepared By Electrolysis Of Co And Ni, Jin-Ping Wei, Xin Sun, Xiao-Yu Wang, Xi-Kui Bian, Jin-Ling Zhai, Yan-Jie Yan-Jie

Journal of Electrochemistry

A new electrolytic method was developed to prepare LiCo_xNi_1-xO₂ as a cathode material of lithium-ion battery. Contrary to the traditional method, electrolytic method is a potential method with simple process to industrialization and no pollution. Metal cobalt and nickel were electrolysed in parallel to prepare the precursor of Co_xNi_{1- x}(OH)₂.Different compositional precursors could be conveniently prepared by changing electrolytic current. The LiCo_0.3Ni_0.7O₂ cathode prepared by this method was found favorable charge-discharge and cycle properties. For the LiCo_0.3Ni_0.7O₂ cathode material, …