Engineering Commons^™

Photonic Band Tuning In 2d Photonic Crystals By Atomic Layer Deposition, Elton Graugnard, Davy P. Gaillot, Simon N. Dunham, Curtis W. Neff, Tsuyoshi Yamashita, Christopher J. Summers

Materials Science and Engineering Faculty Publications and Presentations

Atomic layer deposition (ALD) has become a powerful tool for the fabrication of high quality 3-dimentional photonic crystals (PCs) from both inorganic (opal) and organic (holographically patterned polymer) templates [1,2]. With ALD, highly conformal films can be grown with a precision of 0.05 nm, which, when combined with the availability of a wide range of low temperature film growth protocols, enables a high degree of control over material and structural properties to precisely tune optical properties [3]. Two-dimensional photonic crystals have been developed extensively for applications in optical interconnects, beam steering, and sensor devices; and are predominantly fabricated by electron-beam …

Sub-Surface Corrosion Research On Rock Bolt System, Perforated Ss Sheets And Steel Sets For The Yucca Mountain Repository — Quarterly Technical Report No. 9, Dhanesh Chandra, Jaak J.K. Daemen

Publications (YM)

This report shows the work done for this period in accordance to cooperative agreement of University of Nevada system for the Task 019 “Subsurface Corrosion Research on Rock Bolt System, Perforated SS Sheets and Steel Sets for the Yucca Mountain Repository”, the overall objective of which is to conduct corrosion research and predict the durability of rock-bolts and other underground metallic roof supports. We are performing oxidation tests using Thermogravimetric Analyzer (TGA), and Potentiodynamic tests to determine the corrosion rates of rock bolts, other support materials including bench mark materials.

In this quarter, we have performed:

Potentiodynamic tests were performed …

Comment On “Structural Stability Of Complex Hydrides: Libh4 Revisited”, Duane D. Johnson, Nikolai A. Zarkevich

Duane D. Johnson

A Comment on the Letter by Zbigniew Łodziana and Tejs Vegge, Phys. Rev. Lett. 93, 145501 (2004).

Factors Influencing Engineering Students' Decisions To Cheat By Type Of Assessment, Honor J. Passow, Mathew J. Mayhew, Cynthia J. Finelli, Trevor S. Harding, Donald D. Carpenter

Materials Engineering

Academic dishonesty (cheating) has been prevalent on college campuses for decades, and the percentage of students reporting cheating varies by college major. This study, based on a survey of 643 undergraduate engineering majors at 11 institutions, used two parallel hierarchical multiple regression analyses to predict the frequency of cheating on exams and the frequency of cheating on homework based on eight blocks of independent variables: demographics, pre-college cheating behavior, co-curricular participation, plus five blocks organized around Ajzen's Theory of Planned Behavior (moral obligation not to cheat, attitudes about cheating, evaluation of the costs and benefits of cheating, perceived social pressures …

Structure Effects Of Benzene Hydrogenation Studied With Sum Frequency Generation Vibrational Spectroscopy And Kinetics On Pt(111) And Pt(100) Single-Crystal Surfaces, Kaitlin M. Bratlie, Christopher J. Kliewer, Gabor A. Somorjai

Kaitlin M. Bratlie

Sum frequency generation (SFG) surface vibrational spectroscopy and kinetic measurements using gas chromatography have identified at least two reaction pathways for benzene hydrogenation on the Pt(100) and Pt(111) single-crystal surfaces at Torr pressures. Kinetic studies at low temperatures (310-370 K) show that benzene hydrogenation does not proceed through cyclohexene. A Langmuir-Hinshelwood-type rate law for the low-temperature reaction pathway is identified. The rate-determining step for this pathway is the addition of the first hydrogen atom to adsorbed benzene for both single-crystal surfaces, which is verified by the spectroscopic observation of adsorbed benzene at low temperatures on both the Pt(100) and Pt(111) …

Posterminaries: The Scales Of Judgement, Alexander H. King

Alexander H. King

Materials scientists are generally well-versed in physics, and physics, above all, is a science of measurements. The first instinct of a physicist is to parse a problem in terms of its measurables in the dimensions of mass, length, and time, and it is the shifting of attention down the scale of length that particularly characterizes our present times as the Nano Age.

Modeling Fracture In Z-Pinned Composite Co-Cured Laminates Using Smeared Properties And Cohesive Elements In Dyna3d, Jason K. Freels

Theses and Dissertations

The purpose of the present research was three-fold: 1) gain a more sophisticated understanding of the response of co-cured composite joints with and without through-thickness reinforcement (TTR), 2) compare the behavior of specimens reinforced with various sizes and densities of reinforcement, and 3) use experimental data to verify the existing DYNA3D smeared property model. Double cantilever beam, end-notch flexure and T-section specimens reinforced with 0.011" diameter z-pins at 2% and 4% volume densities were tested to determine the mode I, mode II and mixed mode (I and II) behavior. Results were added to preliminary research in which tests were conducted …

Effects Of Polishing Shot-Peened Surfaces On Fretting Fatigue Behavior Of Ti-6al-4v, Kasey S. Scheel

Theses and Dissertations

The research of this thesis was done to investigate the effects of polishing a shot-peened specimen of Ti-6Al-4V on the fretting fatigue life of that specimen. The shot-peening process, though one of the most beneficial techniques in prolonging fretting fatigue life, creates a textured surface that may lead to problems on the micro level. This research was done in an attempt to further improve the peening process by examining the effects of another surface treatment to be used in conjunction, surface polishing. The rough peened surface may contain abrupt changes in surface geometry that act as stress risers, which are …

Effects Of Environment On Creep Behavior Of Two Oxide-Oxide Ceramic Matrix Composites At 1200°C, Pavlos Koutsoukos

Theses and Dissertations

Previous studies by the advisor and graduate students examined creep behavior of the Nextel720/Alumina CMC in air and in 100% steam environments at 1200 and 1330°C. Results showed that while this oxide/oxide system exhibits an exceptionally high fatigue limit at 1200°C it also experiences substantial strain accumulation under sustained loading conditions. Furthermore, these earlier investigations revealed a significant degrading effect of 100% steam environment on material performance under both static and cyclic loadings. The present effort will investigate creep rupture behavior of Nextel720/Alumina composite in the inert gas environment. In addition, creep rupture behavior of Nextel720/Aluminosilicate CMC will be investigated …

Characterization Of Thermally Diffused Bordie Layers On Aisi 1018 Steel : Residual Stresses (By Synchrotron Radiation) And Microhardness, Joel A. Payne

Theses

Boronization is a thermal diffusion process in which needle like boride layers are formed at the surface of the metallic substrate. The boride coatings formed by the diffusion process have high hardness and strong ware and corrosion resistance. In order for coatings of this nature to be industrially successful, their service life should be long and characterization should be extensive. Measuring the residual stresses of the coatings caters to each of these aspects.

In this study, AISI 1018 steel samples were boronized by a powder-pack process for four hours at 850°C in an argon atmosphere. Characterization techniques included coating thickness, …

Submicron Patterning Using Laser Interference Lithography, Luigi Pollara Verdoni

Theses

In this thesis, the theory, fabrication protocol, and initial results of an alternative nanopatterning technique called Interferometric Lithography (IL) are presented. Comprised of the identical process attributes of traditional projection photolithography, IL mirrors the wafer preparation and development procedures of our existing clean room capabilities. The main departure is solely in means of pattern delineation. IL is a "mask less" technique that employs the interference fringe pattern of two coherent beams, and can therefore be generated with a commercial laser. Due to its simplicity, Interferometric Lithography provides an attractive supplement to existing methods of nano-patterning.

Utilizing a 325 nm HeCd …

Calcined Temperatures Influence On Synthesis And Electrochemistry Charactarization Of Li[Ni_(0.475)Mn_(0.475)Co_(0.05)]O_(2) For Li-Ion Batteries, Li-Qin Wang, Li-Fang Jiao, Hua-Tang Yuan

Journal of Electrochemistry

Layered Li[Ni_(0.475)Mn_(0.475)Co_(0.05)]O_(2) materials have been prepared by a solid-state pyrolysis method.Experiments of XRD,SEM,cyclic voltammetry and charge/discharge cycling were carried out.It can be learned that when calclined at 800 ℃,the sample showed the highest first discharge capacity of 178.8 mAh·g~(-1) at a current density of 20 mA/g in the voltage range 2.3~4.6 V.

Investigations On Electrochemical Characteristics Of Liv_(3)O_(8) Electrode In Lithium Sulfate-Water-Ethanol Electrolytes, An-Bao Yuan

Journal of Electrochemistry

The active material of LiV_(3)O_(8)prepared using low-temperature pre-reaction in solution followed by intermediate-temperature calcination at 450 ℃.The product was characterized by X-ray diffraction analysis and scanning electron microscope observation.The performance of LiV_(3)O_(8) electrode in neutral lithium sulfate-water-ethanol electrolytes was investigated using electrochemical methods.Galvanostatic charge/discharge results indicated that the specific capacity of LiV_(3)O_(8) electrode decreases with ethanol content increasing in electrolyte.The most appropriate water/ethanol volumetric ratio is 4 ∶1 in terms of conductivity of the electrolyte and stability of the electrode.AC impedance measurements demonstrated that the ohmic resistance of the electrolyte as well as the charge transfer resistance of the electrode/electrolyte …

Immobilization Of Cytochrome C On The Surface Of Single-Wall Carbon Nanotube And Its Direct Electron Transfer And Electrocatalysis, Ya-Jing Yin, Ya-Fen Lv, Ping Wu, Pan Du, Yan-Mao Shi, Chen-Xin Cai

Journal of Electrochemistry

Cytochrome c(Cyto c) was immobilized on the surface of the single-wall carbon nanotube(SWNT) by using the method of adsorption.Infrared spectroscopy indicated that the Cyto c remained in its original structure and did not undergo structural change after its immobilization on the SWNT.The direct electrochemistry of cyto c,which was adsorbed on the surface of the SWNT,was studied by cyclic voltammetry.The voltammetric results demonstrated that the SWNT had promoting effects on the direct electron transfer of Cyto c and also indicated that the immobilized Cyto c retained its bioelectrocatalytic activity to the reduction of H_(2)O_(2).This modified electrode might be used in development …

Electrochemical Behavior Of Electrolytic Manganese Dioxide In Mgso_(4) Solution, Dan-Mei Yu, Yu-Jun Si, Chang-Guo Chen, Yu-Ping Liu, Yan Liu

Journal of Electrochemistry

The rechargeability and crystal structure changing of electrolytic manganese dioxide(EMD) in MgSO_(4) electrolyte were investigated by cyclic voltammetry,galvanostatic charge/discharge and X-ray diffraction.The results have shown that the EMD has good rechargeability;after several initial cycles,the charge and discharge became stability;after discharge,the γ-MnO_(2) structure of EMD was changed,the production was reversible and could be recharged to γ-MnO_(2) structure again which ensured the rechargeability of EMD.

Electrodeposition Of Nano-Sb-Zn Alloy In Acetamide-Urea-Nabr-Kbr Melt, Peng Liu, Xin-Ai Guo, Ye-Xiang Tong, Qi-Qin Yang

Journal of Electrochemistry

The electroreduction of Zn(II) and Sb(III) in acetamide-urea-NaBr-KBr(343 K) were studied by cyclic volatmmetry.The reduction of Zn(II) or Sb(III) to the metals is an irreversible process.The transfer coefficient of Zn(II)+2e→Zn and Sb(III) +3e→Sb were calculated to be 0.231 and 0.319,the diffusion coefficient of Zn(II) and Sb(III) in the melt were determined as 1.70 10~(-6) and 3.21 10~(-6) cm~(2)· s~(-1) respectively.The Zn-Sb films with different Zn content from 29.67 at% to 97.34 at% were electrodeposited in acetamide-urea-NaBr-KBr melt at 343 K by controlling the deposition potential and the Zn(II)/Sb(III) molar ratio.The morphology of Zn-Sb film was observed by SEM.Zn-Sb film comprises …

Investigation On The Resistance To Electrochemical Oxidation Of Carbon Nanotubes With Various Diameters, Yu-Yan Shao, Ge-Ping Yin, Yun-Zhi Gao, Peng-Fei Shi

Journal of Electrochemistry

The resistance to electrochemical oxidation of multi-wall carbon nanotubes(CNT) with various diameters is investigated by applying a fixed potential of 1.2 V(RHE) for 120 h in 0.5 mol L~(-1) H_(2)SO_(4).The oxidation current of CNTs decreases with their diameters,but CNTs between 10~20 nm in diameter(D1020) shows the lowest oxidation current.XPS analysis shows that,after oxidation,the increase in surface oxygen for D1020 is the smallest,implying that the oxidation degree for D1020 is the lowest.The conclusion can be reached that CNTs between 10~20 nm in diameter are the most resistant to electrochemical oxidation.The difference in electrochemical stability of CNTs is attributed to the difference …

Pre-Oxidative Amperometric Glucose Biosensor Incorporated With Carbon Nanotube And Pbo_(2), Hong-Lan Qi, Cheng-Xiao Zhang

Journal of Electrochemistry

A pre-oxidative amperometric glucose biosensor incorporated with carbon nanotube,ferrocenemonocarboxylic acid and PbO_(2) was designed.The interferences coming from reduced substances,such as ascoribic acid and urine acid were eliminated by PbO_(2).The oxidative current is linear at the potential of +0.40 V(vs.SCE) to the concentration of glucose in the range from 0.50 to 20 mmol·L~(-1),and the detection limit of glucose is 0.1 mol L~(-1).The relative standard deviation is 3.3% for seven successive assays at 5.0 mmol·L~(-1)glucose.This biosensors have been applied to determination of the glucose in serum with satisfying results.

Study On The Preparetion And Electrochemical Beavior Of Nitrogen Doped Tetrahedral Amorphous Carbon Electrode, Ke Liu

Journal of Electrochemistry

taC∶N films are a good materials for semiconductor electrodes.But further studies are hampered by the ohmic contact problem,which occurs between the silicon and the lead.By studying the influence of heat treatment on the film's property,it is believed that ohmic contact should be made on the silicon first,and then the film be deposited.A set of taC∶N electrodes with various nitrogen content have been prepared.CV study indicates that the cathodic limits move slowly to positive direction.while the anodic limits are unchanged with the increasing of nitrogen content.As a result,the electrochemical windows get narrow either.

Preparation And Supercapacitor Properties Of Yttrium Doped Nio, Dan-Dan Han

Journal of Electrochemistry

Yttrium doped Nano-NiO were synthesized by chemical precipitation method.Characterization and performance of the samples were studied by X-ray diffraction,the results showed that the doping Yttrium did not change the crystal structure of NiO,but the size of crystalline grain was reduced.The electrochemical properties of the electrode materials were measured in the three electrode system.Electrochemical properties of NiO were researched by cyclic voltammetry,constant current charge/discharge and AC impedance methods.It could be seen that the chemical doping improved the specific capacitance and the utilization of active materials.When the weight ratio of NiO with Y_(2)O_(3)was 1∶0.1,the composite material had the best properties.The maximum discharge …

Voltammetric Behavior And Its Determination Of Acetaminophen At Poly (Congo Red) Modified Electrode, Hong-Bin Luo, Ya-Feng Zhang, Wei Chen, Xin-Hua Lin

Journal of Electrochemistry

Cyclic voltammetry was used to prepare poly(Congo Red) film on glassy carbon electrode and to study the electrochemical behavior of acetaminophen on poly(congo red) modified electrode.Experimental resultal shows that the poly(congo red) modified electrode exhibits excellent electrocatalytic effect on the oxidation of acetaminophen.The peak currents of linear sweep voltammogram are linear to the acetaminophen concentrations over the range of 2.0×10~(-7) ～2.0×10~(-6) mol·L~(-1).The detection limit has been estimated to be 4.0×10~(-8) mol·L~(-1).This method can be used for the determination of acetaminophenin real sample.

The Influence Of Pva As Disperser On Lifepo_(4) Synthesized By Hydrothermal Reaction, Hui-Lin Li, Hui Zhan

Journal of Electrochemistry

LiFePO_(4) was synthesized by means of hydrothermal reaction,in which PVA acts as disperser and glucose as carbon source.The samples were characterized by X-ray diffraction,scanning electron microscopy and electrochemical measurement.SEM results show that the sample is homogeneously composed of grains with a particle size of ca.200nm.In the charge/discharge test,the products exhibited a 3.45V discharge voltage plateau and a maximum specific capacity of 140mAh/g.After 40 cycles,its capacity only declined by 2.1%.Besides these,the mechanism for the influence of the particle size and carbon coating on the electrochemical property of LiFePO_(4)material was discussed in detail.

Study On The Microstructure Of Pb-Sn Alloy Obtained From Quasi-Two-Dimensional Electrodeposition, Bin Sun

Journal of Electrochemistry

A two-layered structure of eutectic-solid sulotion is formed in the microstructure of Pb-Sn alloy obtained from quasi-two-dimensional electrodeposition.It is showed that this unique structure is caused by the variation of the current density on the growth interface.When the interface is located in the front of the whole deposits,the current density is high.So the Pb and Sn can deposit together and the eutectic texture forms.When the interface is in the rear of the whole deposits,the current density is low.At this moment the electrodeposition of Pb is the dominant reaction,and the Pb-based solid solution appears.

Influence Of Crystallinity On The Kinetics Of Li Ion Insertation And Deinsertation In Spinel Limn_(2)O_(4), Rong-Hua Zeng, Dong-Sheng Lv, Wei-Shan Li

Journal of Electrochemistry

Two spinel lithium manganese oxides of different crystallinity were prepared by sol-gel process and were studied by using inducfively coupled plasma,X-ray diffraction,scaning electron micrographs,constant charging and discharging,cyclic voltammetry and electrochemical impedance spectrometry,the results show that the sample treated under 700 ℃ has higher crystallinity than the sample treated under 500 ℃,however,the sample with lower crystallinity has higher discharge capacity and better cyclic performance that due to quicker charge exchange speed and quicker diffusion speed of Li-ion.

Studies On Performance And Electrode Materials For All Vanadium Flow Battery, Yuan Jun

Journal of Electrochemistry

In this paper,cyclic voltammetry has been used to study the electrochemical performance of the treated and untreated graphite,soft graphite and PAN-carbon cloth in vanadium sulfate solution.The results show that: the reversibility of reaction can be improved on the surface of treated electrode,and the current can also increase;the electrochemical performance of treated electrode is remarkably enhanced;in the process of charge/discharge,the charge current can reach up to 20 mA/cm~(2),and discharge current up to 15 mA/cm~(2);surface morphology of the treated and untreated graphite show that the treatment can change the surface structure of electrode and also add the reaction area.

Studies On Synthesis And Electrochemical Performance Of Li_(X)Ni_(1/3)Mn_(1/3)Co_(1/3)O_(2) As Cathode Material For Lithium Ion Batteries, Xiao-Jian Guo, Jie Li, Yi-Xiao Li, Yong Yang

Journal of Electrochemistry

A series of LiNi_(1/3)Mn_(1/3)Co_(1/3)O_(2) were synthesized by a combined hydroxides coprecipitation and calcination method.Effects of synthesizing temperature of coprecipitations and the Li∶M ratios on structure and electrochemical performance of the materials were studied.The results showed that materials synthesized with coprecipitation at room temperature(~20 ~(o)C) delivered the best electrochemical performance.Another series of cathode materials Li_(x)Ni_(1/3)Mn_(1/3)Co_(1/3)O_(2) with different Li∶M ratios were synthesized with this method.The results showed that sintering at high temperature could cause loss of LiOH,thus more LiOH should be added.It is demonstrated that Li_(1.08)Ni_(1/3)Mn_(1/3)Co_(1/3)O_(2) had the best electrochemical performance.

The Property Study Of Libob-Pc/Dec Electrolyte, Ying-Kun Ning, Bi-Tao Yu, Fu-Shen Li, Wei-Hua Qiu

Journal of Electrochemistry

The new electrolyte salt LiBOB for Li-ion battery was synthesized in laboratory,and series of electrolytes of LiBOB and PC/DEC was compounded.The conductivity of the electrolytes was compared by changing the temperature and concentration.The cycling performance of charging-discharging was also compared by the charging-discharging test,the results showed that the varying regularity of conductivities and cycling stability and capacity were not always identical,but there were a suitable electrolyte for Li/ARG cell.The A.C.impedance and CV were used to test the compatibility of the most suitable electrolyte and ARG anode.Conclusion can be drawn that the ARG anode can be protected very well by SEI …

Recycling Of The Spent Nickel-Cadmium Batteries Based On Bioleaching Process, Liang-Shu Xia, Shi-Fu Fu, Zhong-Qing Chen

Journal of Electrochemistry

Less than 1 percent of discarded dry batteries are recovered in china.it is necessary to find an economic,fast and environmentally friendly process to recycle spent dry batteries.Bioleaching is better one of the few technology applied for the recovery of the toxic metals from hazardous spent batteries.In this study,after the acidified sludge made by the inoculated and cultured indigenous sewage sludge was acted as leaching bacteria species,the influence of the different pH values,the different residence time of the sludge in bioreactor(RTB),the leaching time,whether or not adding Fe(iron powder) to the leaching liquid on the leaching rate of Ni,Cd was tested.The results …

Research Of Explosion Mechanism Of Lithium-Ion Battery, Yu-Hong Chen, Zhi-Yuan Tang

Journal of Electrochemistry

The heat character of Lithium-ion battery materials and explosion mechanism of Lithium-ion cells under the overcharge,short-circuit and other abuse behavior are tested by C_(80) calorimeter,_()DSC and charge-discharge instrument.SEI reactions,Li_xC_(6)/electrolyte and Li_xC_(6)/PVDF reactions take place at the anodes.Electrolyte and solvent reactions happen after 178℃ and Li_(1-x)Co_(1/3)Ni_(1/3)Mn_(1/3)O_(2) decomposes after 230℃.The batteries explode at 150℃ oven test or 1.5C,5.5 V overcharge and do not explode at short-circuit.

Investigation Of The Direct Electrochemical Reduction Of Cr_(2)O_(3) Powder In Molten Cacl_(2) By A Metallic Cavity Electrode, Guo-Hong Qiu, Di-Hua Wang, Xian-Bo Jin, Xiao-Hong Hu, Zheng Chen

Journal of Electrochemistry

A metallic cavity electrode is used for further investigation of the electrochemical behaviour of(Cr_(2)O_3) powder in molten CaCl_(2)(Na: ~0.02% by mass,Mg: < 0.005% by mass) at 900 ℃.The Cr_(2)O_(3) powder reduction mechanism was confirmed in line with EDX and SEM analysis of the potentiostatic electrolysis products.The correlations between the particle size of metallised product and the electrolysis potential,or electrolysis time were analysed.