Engineering Commons^™

Development Of Dehydrogenase-Based Bioanode Using Poly(Phenosafranin)-Functionalized Swcnt Nanocomposites And Its Application To Ethanol Biosensor, S. Saleh Farhana, Okajima Takeyoshi, Mao Lanqun, Takeo Ohsaka

Journal of Electrochemistry

A New type of dehydrogenase-based amperometric ethanol biosensor was constructed using alcohol dehydrogenase (ADH) which was immobilized on the edge-plane pyrolytic graphite (EPPG) electrode modified with poly(phenosafranin)-functionalized single-walled carbon nanotube (PPS-SWCNT). The PPS-SWCNT modified EPPG electrode was prepared by electropolymerization of phenosafranin on the EPPG electrode which was previously coated with SWCNT. The performance of the ADH/PPS-SWCNT/EPPG electrode was evaluated using cyclic voltammetry and amperometry in the presence of ethanol. The fabricated ethanol biosensor provided a reasonable sensitivity of 2.0 μA cm–2 mM–1 and a low detection limit (36 μM) for the electrocatalytic oxidation of ethanol with a linear concentration …

Electrochemical Performance Of Tin Dioxide/Carbon Xerogel Composites As Anode Materials For Lithium-Ion Batteries, Xiao-Jing Liu, Lin-Lin Qin, Yi-Ning Shi, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

The tin dioxide/carbon xerogel composites were synthesized by using vacuum infiltration method. Structural characterization and morphology of the composites were investigated by using XRD, TEM and SEM techniques. BET test was performed to determine the pore size distributions of carbon xerogels and the composites. The results showed that the nano-sized SnO2 particles (5~10 nm) were encapsulated in the pores of carbon xerogels. During the electrochemical tests the SnO2 in the composites exhibited capacity retention of 61.9% after 100 cycles of charge-discharge tests at 100 mA/g.

Study On The Electrochemical Behaviors Of Gc Electrode Modified With Carbon Nanotube-Polyelectrolytes And Its Application For Rutin Detection, Liang Hua, Xia-Qin Wu, Rong Wang

Journal of Electrochemistry

The electrochemical behaviors of rutin and ascorbic acid at single-wall carbon nanotube and polyelectrolytes (dimethyl-diallylammonium chloride, PDDA) film modified glassy carbon electrode was investigated. The cyclic voltammetric results showed that electron transfer of rutin at PDDA/SWCNTs/GC modified electrode is an adsorption-controlled process. The separation of oxidation peak potentials of rutin and ascorbic acid was more than 200 mV. The rutin concentration in the presence of AA were detected by differential pulse voltammetry (DPV). The experimental results indicated that the PDDA/SWCNTs/GC modified electrode can be used for the detection of rutin in the presence of high concentration of AA. The DPV …

Brief Introduction To Metal Corrosion And Protection, Hou-Yi Ma, Cong-Ying Cui, Ting Chen

Journal of Electrochemistry

This paper explains why corrosion processes are usually electrochemical in nature, describes the significance of electrochemical kinetic parameters of corrosion process, and briefly introduces the principles of corrosion protection, the most common corrosion protection methods and some special application of corrosion processes.

Effects Of Graphene On Electrochemical Behaviors Of Ni(Oh)2 As Supercapacitor Material, Zhen-Zhen Zhao, Wen-Bin Ni, Neng-Yue Gao, Hong-Bo Wang, Jian-Wei Zhao

Journal of Electrochemistry

The enhanced electrochemical properties of Ni(OH)2 by the oxidation defected graphene were studied by both experimental method and theoretical calculation. The composite material of nano-Ni(OH)2/graphene was prepared by potentiostatic deposition on the graphene substrate. Observed by TEM, the Ni(OH)2 nanoparticles were well dispersed on the graphene substrate with the diameter of 5.0±0.5 nm. The capacitance of the system measured by the electrochemical test was 1928 F?g-1. As indicated by the theoretical calculations, the composite material becomes conductive since Ni(OH)2 is combined with surface functional groups of the graphene through the strong chemical interaction. The electrons transfer from the graphene substrate …

Synthesis Of Limnpo4/C Used As Cathode Material For Lithium Ion Batteries, Xin Yang, Xue-Wu Liu, Gui-Chang Liu, Zhi-Cong Shi, Xin Li, Guo-Hua Chen

Journal of Electrochemistry

The LiMnPO4/C composites were prepared using a solid-state reaction with addition of the resorcinol formaldehyde resin as the carbon source. The effects of reaction temperature and time on the crystal structure, morphology and electrochemical properties of the LiMnPO4/C composites were investigated. The results show that the best performance was achieved with the LiMnPO4/C composites synthesized at 600 oC for 12 h which had the particle sizes about 100~200 nm. The initial discharge capacities were 121.6 mAh?g-1 at 0.02C, 110 mAh?g-1 at 0.1C and more than 60 mAh?g-1 at 1C. An overall reversible capacity of 110 mAh?g-1 had been retained after …

Photogenerated Cathodic Protection Of Stainless Steel, Cheng-Gang Lin, Ze-Quan Lin, Jing Li, Chang-Jian Lin

Journal of Electrochemistry

A highly ordered Co-doped TiO2 nanotube layers were fabricated by potentiostatic anodization of pure titanium in fluorinated electrolyte solutions followed by ion-exchange method. The structure and composition of the as-prepared Co-doped TiO2 nanotube layers were characterized by SEM, XRD, UV-Vis, and XPS. The effects of dopant content on the morphologies, structural and photochemical properties of the TiO2 nanotube arrays were investigated. The performances of photogenerated cathodic protection and the photoelectrochemical response for the Co-doped TiO2 nanotube arrays under illumination and dark conditions were evaluated through the electrochemical measurements. The Co-doped TiO2 nanotubes showed a stronger absorption in the visible light …

Corrosion Characteristics Of Galvanized Flat Steel For Power Grounding In Nacl Solution Medium, Yong Li, Gao-Lin Wu, Bang-Fei Deng, Ping Yang, Xue-Ming Li, Qing-Bin Zong

Journal of Electrochemistry

The corrosion behavior of power grounding galvanized flat steel was studied by polarization measurement, electrochemical impedance spectroscopy and neutral salt spray test in 5% NaCl solutions. The surface morphologies of galvanized coating and structural properties of corrosion products were observed with scanning electron microscope and X-ray diffraction spectrometer, respectively. Results showed that under the temperatures of 20~60℃, the corrosion currents of galvanized flat steel increased with the temperature rising. The corrosion rate at 60℃ was 0.8408 mA?cm-2, which is 2.9 times larger than that at 20℃. The corrosion rate dropped after reaching the maximal value of 1.95 mg?cm-2?d-1 when the …

Electrochemical Performances Of C-Coating And Co-Doping Lifepo4, Ying Bai, Jue-Ming Yang, Chun-Bo Qing, Wei-Feng Zhang

Journal of Electrochemistry

Phospho-olivine LiFePO4 cathode materials were prepared by hydrothermal reaction at 200 oC. Sucrose was added as C-coating resource and Co was doped into the crystal lattice of LiFePO4. In order to investigate the improvements in the electrochemical properties of Co-doped LiFePO4, three samples, LiFePO4, C-coated LiFePO4 and C-coating-Co-doped LiFePO4, were synthesized under the same preparation conditions. Charge/discharge studies reveal that the Co-doped LiFePO4/C composite annealed at 400 oC exhibits marked improvement of specific capacity by diminishing the particle sizes and enhancement in the degree of crystallinity. The C-coating and Co-doped into the LiFePO4 crystal lattices improve the rate performance through …

Simultaneous Determination Of Dopamine(Da)And Epinephrine (Ep) At Ca/Gc Electrode, Wang Ren, Ying Zhang, Min-Jiao Li

Journal of Electrochemistry

The citric acid modified glassy carbon electrode (CA/GC) was prepared by potentiostatic technique and was used for detections of dopamine (DA), epinephrine (EP), and their mixtures by differential pulse voltammetry (DPV). The modified electrode shows the enhanced sensitivity and excellent electrochemical discrimination to DA and EP. The cathodic potential difference between DA and EP was about 380 mV, while no cathodic reduction of ascorbic acid (AA) was observed because the oxidation of AA is an irreversible reaction at the sensor. As a result, DA and EP could be determined simultaneously with the interferences of high concentrations of AA being eliminated. …

Study On The Fluorescent Carbon Nanodots With Electrochemical Methods, Bao-Ping Qi, Yan-Min Long, Lei Bao, Cui Liu, Zhi-Ling Zhang, Dai-Wen Pang

Journal of Electrochemistry

Carbon nanodots are a new class of fluorescent nanoparticles with a carbon-based core, which possess wavelength-tunable luminescence, high photostability, resistance to photobleaching, water-solubility, and ease of bioconjugation. Owing to their attractive merits, carbon nanodots like other carbon nanomaterials such as fullerene, carbon nanotubes and graphene, have attracted much attention. In addition, carbon nanodots can be inexpensively produced by electrochemical methods with simple post-processing under mild conditions. Electrochemical approaches have unique advantages in the analysis of surface structures and luminescence mechanism of materials. In this review, recent advances in electrochemical methods used for the synthesis and luminescence mechanism of fluorescent carbon …

Surface Diffusion Of Adsorptive Species On Gold Nanoelectrodes, Bao-Fa Su, Wei Wang, Dong-Ping Zhan, Bin Ren, Zhong-Qun Tian

Journal of Electrochemistry

Gold nanoelectrodes were prepared successfully by a programmed laser puller. The Faraday adsorptions of oxygen and iodine, and the underpotential deposition of lead on the gold nanoelectrodes were investigated. The results showed that the active areas of nanoelectrodes were dramatically higher than their appearant geometry areas, which is caused by the surface diffusion of adsorptive species from the nanoscale gold/electrolyte interface to the adjacent gold surface.

Study On Residual Powders Of Lithium-Ion Batteries With Different Voltages After Explosion, He Li, Zhi-Kui Chen, Ji-Na Cao, Guang-Chuan Liang

Journal of Electrochemistry

The residual powders of lithium-ion batteries at different voltages after explosion were obtained by using the battery impact testing machine. And these powders have been investigated by weighing, water solution and X-ray diffraction (XRD). The results showed that the integrity status of copper current collector and weight of residual powders decreased gradually with increasing of battery voltage, rising of burning temperature and releasing of burning duration time. The residual powders could be separated to insoluble powders and soluble powders by the water solution. The proportion of the insoluble powders is more (about 90%) including C, Co and CoO, while the …

Undergraduate Research Opportunities Program 2011, Nicholle Booker, University Of Nevada, Las Vegas

Undergraduate Research Opportunities Program (UROP)

Undergraduate Research Opportunities Program

On August 9, 2011 the UNLV College of Sciences will celebrate the accomplishments of undergraduate students participating in the Summer 2011 Undergraduate Research Opportunities Program (UROP) and the Research Experience For Undergraduates (REU) Program.

The public is invited to attend, beginning at 10:00 a.m.

Please join us to view student research posters. Student research topics include: biomedicine and human health, Nevada's fragile environment and ecosystems, climate change, stem cell research, microbiology, astrophysics, and many others.

Over 25 UNLV undergraduates and a cohort of 25 undergraduates selected from colleges and universities across the nation will mark the …

Effect Of Au Content On Microstructural Evolution Of Snagcu Solder Joints That Undergo Isothermal Aging And Reliability Testing, Patrick J. Hyland

Master's Theses

Electronics, especially, printed circuit boards (PCBs) are a widespread technology. Metal coatings or “surface finishes” are often added to PCB board pads and component leads during manufacturing to improve their performance. Electroplated nickel/gold over copper is a popular surface finish for printed circuit boards and component leads. The presence of gold in solder joints, however, is known to have detrimental effects referred to as gold embrittlement. It is generally understood that tin-lead solder joints with less than 3 weight percent (wt%) of gold will not experience reliability issues. The acceptable level of gold in lead-free solder joints, however, is less …

Design Optimization Of An Lpg Thermal Cracker For Multiple Objectives, Reza Nabavi, G.P Rangaiah, A Niaei, D Salari

Seyed Reza nabavi

Ethylene and propylene, building blocks of the petrochemical industries, are mostly produced by steam cracking of hydrocarbons. In our recent work (Nabavi, Rangaiah, Niaei and Salari, Multiobjective Optimization of an Industrial LPG Thermal Cracker using a First Principles Model, Ind. Eng. Chem. Res. 2009, 48, 9523-9533), operation of an industrial liquefied petroleum gas (LPG) cracker was optimized for several sets of two and three objectives. In this work, optimization of an LPG cracker design is investigated for multiple objectives. The objectives considered are maximization of annual ethylene and propylene production, selectivity and run length, and minimization of severity and total …

Concentration Oscillations In The Processes Of Unsaturated Compounds Oxidative Carbonylation. 1. Processes Of Acetylene And Phenylacetylene Oxidative Carbonylation (In Russian), Sergey N. Gorodsky, Katarina Novakovic

Sergey N. Gorodsky

This review describes the processes of oxidative carbonylation of acetylene and phenylacetylene, occurring in the oscillatory mode under conditions of homogeneous catalysis by palladium complexes.

Miniature Mass Spectrometry: Rf Amplitude Control System Design, Matthew Allen Kirleis

Purdue Polytechnic Masters Theses

This thesis covers the methods used to construct and characterize a custom digital RF amplitude control system. Many types of mass spectrometers exist, but few have been miniaturized as much as the Mini instruments developed at Purdue University. The goal of this research was to improve upon an earlier amplitude control system consisting of analog circuits first implemented in the Mini 11.5 mass spectrometer developed at Purdue University.

A custom set of control and data acquisition electronics were developed for testing the digital and analog control systems in a Mini 11.5 mass spectrometer chassis. A MATLAB Simulink simulation was done …

53rd Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 53rd annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Snowmass, Colorado, July 24-28, 2011.

New Nanosystem Mixed Reactor For Urban Wastewater Treatment, Masoud Rastegar, Kamran Rahmati Shadbad

Masoud Rastegar

No abstract provided.

Do Wind Turbines Affect Weather Conditions?: A Case Study In Indiana, Meghan F. Henschen, Brittany Herrholtz, Lacey Rhudy, Kathryn Demchak, Brian Doogs, Joshua Holland, Erik Larson, Johnny Martin, Matthew Rudkin

The Journal of Purdue Undergraduate Research

Wind turbines are becoming increasingly widespread in the United States as the world looks for cleaner sources of energy. Scientists, policymakers, and citizens have strong opinions regarding the positive and negative effects of wind energy projects, and there is a great deal of misinformation about wind energy circulating on the Web and other media sources. The purpose of this study is to gain a better understanding of how the rotation of hundreds of turbines can influence local weather conditions within a wind farm and in the surrounding areas. This experiment measures temperature, atmospheric pressure, wind speed, wind direction, relative humidity, …

Vuv Absorption Cross Section Of Benzene, Relevance For Titan’S Atmosphere, F-J. Capalbo, Y. Bénilan, N. Fray, M. Schwell, Et. Es-Sebbar, N. Champion, T. Koskinen, R. Yelle

Dr. Et-touhami Es-sebbar

Saturn's largest satellite, Titan, is the only one in the Solar System known to have a thick N2/CH4, planet like atmosphere. The dissociation of these principal components and the recombination of the products make this atmosphere to be rich in organic compounds of high interest for astrobiology. Solar and stellar occultations observed by the Ultraviolet Imaging Spectrograph (UVIS) on board the Cassini spacecraft can be used to characterize the composition of Titan’s upper atmosphere (400 – 1400 km). The results depend strongly on the knowledge of the molecular absorption cross sections of the atmospheric constituents (Ferradaz et al. 2009). This …

Using Nanotechnology To Detect Nerve Agents, Mark N. Goltz, Dong-Shik Kim, Leeann Racz

Faculty Publications

Nanotechnology has opened a wide range of opportunities having potential impacts in areas as diverse as medicine and consumer products. In collaboration with researchers at the University of Toledo UT, Air Force Institute of Technology AFIT scientists are exploring the possibility of using a nanoscale organic matrix to detect organophosphate OP nerve agents. Current techniques for detecting OP compounds are expensive and time consuming. Developing a nanoscale organic matrix sensor would allow for direct, real-time sensing under field conditions. This article describes the science behind such a sensor and its possible applications. High-performance sensors are needed to protect Soldiers and …

Effect Of Freshman Chemistry On Student Performance In Sophomore Engineering Courses, Michael A. Collura, Shannon Ciston, Nancy Ortins Savage

Chemistry and Chemical Engineering Faculty Publications

The role of first year chemistry courses in engineering programs varies somewhat across programs and disciplines. Clearly most engineering majors will encounter chemistry topics of a general nature in some of their upper-level course work. The purpose of requiring chemistry in the first year, however, goes well beyond learning chemical concepts. As a quantitative science, chemistry requires the use of math, principally algebra, on a regular basis in solving various problems. Students should gain an appreciation of the importance of units in solving problems should come to understand the difference between implicit and explicit properties and should develop other quantitative …

Modelling Of The Adsorption‐Catalytic Processes In The Multi‐Dispersed Bed, Sergey V. Zazhigalov, Natali A. Chumakova, Andrey N. Zagoruiko

Andrey N Zagoruiko

The simulation work is dedicated to the multidispersed adsorption-catalytic packing, consisting of comparatively large pellets (say, 5-10 mm) of the catalyst-adsorbent and of catalytically active micro-fibers with typical thickness of ~10 microns. During the heating at the regeneration stage the micro-fiber catalyst must be heated much more rapidly than adsorbent-catalyst, due to the much higher unit outer surface area improving the heat exchange. When the adsorbent-catalyst temperature is becoming high enough for partial desorption of chemisorbed VOC, the temperature of the micro-fibrous catalyst will be already as high as necessary one for complete oxidation of desorbed VOCs. This theoretical concept …

Process Of Combined Oxidation Of Co And So2 In Waste Gases Of Non‐Ferrous Smelters At Platinum Glass‐Fiber Catalyst, Sergey V. Vanag, Andrey N. Zagoruiko

Andrey N Zagoruiko

The work is dedicated to the development of the efficient catalyst for the oxidation of CO in presence of significant amounts of SO2. It was experimentally shown that the Pt/Zr-Si glas-fiber-based catalyst is capable to provide complete CO conversion in SO2 presence at temperatures less 300 С, at the same time showing high resistance to deactivation. Application of such catalyst in the reverse-process will allow to raise essentially efficiency of purification of waste metallurgical gases from SO2 under presence of significant amounts (up to 1-2% vol.) of CO.

New Developments In The Area Of Nonstationary And Sorption-Enhanced Catalytic Processes, Andrey N. Zagoruiko

Andrey N Zagoruiko

The presentation is dedicated to catalytic processes performed under artificially created catalyst nonstationarity. It is shown that the highest technological effect can be achieved for a controlled combination of the thermal nonstationarity with the composition nonstationarity of the catalyst surface. Prospective for application of unsteady catalytic and sorption-catalytic processes are analyzed for different case applications: VOC incineration, hydrogen production by steam conversion of hydrocarbons and organic feedsctock, selective anaerobic oxidation of hydrocarbons. In general, unsteady state and sorption-catalytic ideology discovers new degrees of freedom for process development and may become the basement for new generation of highly-efficient catalytic technologies in …

Artificial Muscle Project: Process Development Of Polydimethyl Siloxane Thin Films For Use In Dielectric Electroactive Polymer Artificial Muscle Actuators, Vincent J. Gayotin, Richard W. Morrison, Paul A. Preisser

Materials Engineering

An artificial muscle design was created founded on the principles of a dielectric electroactive polymer (DEAP), which is fundamentally similar to a capacitor. A polydimethyl siloxane (PDMS)-based elastomer, Sylgard 184 from Dow Corning, was chosen for the design and spun coat onto polystyrene (PS) Petri dishes at varying speeds to create a thin film, using speeds of 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, and 6000 rpm. The film thicknesses were measured optically through use of a microscope with coupled computer imaging software to generate a characteristic curve of film thickness to spin speed, achieving a minimum film thickness …

The Effects Of Cure Schedule On Properties Of Glass-Fiber Reinforced Epoxy Matrix Composites, Trevor J. Lee

Materials Engineering

Two different two-component resin systems were cured, via Differential Scanning Calorimetry, for the times recommended by their respective manufacturers. The resin cure schedules were designed to simulate typical and attainable processing conditions; they were cured at 120°F, 140°F, and 160°F, and in-mold post-cured at 200°F, 230°F, and 260°F. The resulting scans were then compared to a baseline cure for each resin system, consisting of two heating-cooling cycles at a constant rate of temperature change. These baseline cures were then used to determine the percent cure of each sample and the shift in glass transition temperature between the baseline cure and …

Unlv Stars Unabridged Report, University Of Nevada, Las Vegas

Reports (USI)

University of Nevada, Las Vegas, by earning a 2011 Silver Rating in the Sustainability Tracking, Assessment & Ratings System (STARS), is ahead of the curve among public universities – and improving.

STARS is a voluntary, self–reporting framework developed by the Association for the Advancement of Sustainability in Higher Education (AASHE) to help measure sustainability performance over time and among colleges and universities nationwide. The UNLV Sustainability Council oversaw STARS, which by measuring sustainability can help UNLV to reduce energy consumption and waste, improve education, attract research, and generate jobs.

A rating of Silver puts UNLV in great company – with …