Materials Science and Engineering Commons^™

Useful Approaches To Preventing Academic Dishonesty In The Classroom, Trevor S. Harding

Materials Engineering

Over the past three decades, academic dishonesty (a.k.a. cheating) has become an increasingly common occurrence among college-aged students, and engineering students are known to be among the most frequent culprits. At most universities, cheating is dealt with after the fact. Few institutions go beyond drafting an academic integrity policy to prevent cheating before it happens. The same situation exists in the classroom. The majority of college professors report doing little or nothing to reduce the frequency of cheating in their classes, usually because of a lack of awareness of its occurrence. And when cheating is observed, faculty overwhelmingly choose to …

On The Frequency And Causes Of Academic Dishonesty Among Engineering Students, Trevor S. Harding

Materials Engineering

According to studies of self-reported academic dishonesty conducted over time, cheating among college students has been on the increase since at least the 1940’s. This is especially true for engineering students who are now among the most likely to cheat compared to other disciplines. This paper will present a synopsis of the literature on academic dishonesty. In addition, the results of a pilot study on cheating among engineering students conducted at a small mid-western private engineering school are described. Engineering students in an introductory engineering materials course were asked to complete a survey on their perceptions of cheating; therefore, all …

Plasma Deposition Of Spin Chucks To Reduce Contamination Of Silicon Wafers, Richard N. Savage, Emir Gurer, Ed C. Lee

Materials Engineering

An apparatus for delivering a fluidic media to a wafer includes a housing defining a process chamber. A fluidic media delivery member is coupled to the process chamber. A rotatable chuck is positioned in the process chamber. The rotatable chuck has a wafer support surface coated with a coating material. A vacuum supply line is coupled to the rotatable chuck.

Assessment Of The Recycled Concrete Aggregates Structural Suitability For Road Construction, Abdulla Yousef Ali Al-Ali

Theses

In most aspects of modem life, there is a consensus among practitioners and decision makers of the importance of preserving the environment, and to find alternatives to the scarce natural materials. This can be accomplished by better utilization of the natural materials and/or recycling or reclaiming their waste, specially, if they are of finite resources. The recycled material could be an attractive alternative (both environmentally and economically) if its characteristics are proven to be close to those of the natural material.

Utilizing recycled mineral aggregates in the construction field in general and in highway pavement in specific is somehow governed …

Evaluation Of Some Organic Inhibitors For Stainless Steel Corrosion Using Different Electrochemical And Surface Techniques, Maryam Hassan Saeed Al-Hassan

Theses

Stainless steels have been extensively used in automotive, industrial, electronics, etc., applications. Iron (Fe) and chromium (Cr) are the main elements with weight percentage contribution of 60-75% and 10-25% respectively. Other elements, such as Ni, Co, Mo, Mn, C etc. are also present with variable concentrations. The purpose of this work is to use different electrochemical and surface techniques to study the corrosion behavior of stainless steel type 316 (percent composition of different chemical elements are listed in table 1) in acid media in presence and absence of different thiophene derivatives (list of inhibitors in figure 1). Moreover, other important …

Impedance And Photo-Electrochemical Properties Of Oxide Films On Stainless Steel Formed By Different Polarization Techniques, Mona Salim Saleh Ai Kaabi

Theses

Stainless steel alloys have a very active and important role in industry. Because many of

These industries have to work in aggressive media; stainless steels are threatened by corrosion

Which may affect their performance and cost the manufacturers millions of dollars yearly.

Several treatments have been taken part to solve this problem; one is by forming a protective

Oxide layer on the stainless steel (SS) surface to prevent it from corrosion. In this thesis; this way of protecting SS Surface is applied to two different types of Stainless Steel, those are AISI 316 and AISI 31 0; respectively. The oxide …

Neural Networks For Estimating Concrete, Lokman M. Sharara

Archived Theses and Dissertations

No abstract provided.

Time-Resolved Photoluminescence Of Inas/Gainsb Quantum Well Lasers, Michael R. Mckay

Theses and Dissertations

In the world of semiconductor photonic device fabrication, one important objective may be to extract as much light as possible from the device. In these devices, photons are created when electrons recombine with holes by transitioning from a high-energy state to a lower one. Unfortunately, electron-hole recombination does not always result in the formation of a photon. There are three basic types of recombination: the first results in the formation of a photon and is called radiative recombination; and the second and third, known as Shockley-Read-Hall and Auger recombination, result in the heating of the device and do not produce …

Single-Sided Noninvasive Inspection Of Multielement Sample Using Fan-Beam Multiplexed Compton Scatter Tomography, Matthew A. Lange

Theses and Dissertations

As aircraft age, corrosion forms upon unobservable surfaces, particularly at the junction of the sheet aluminum and the steel rivets used to attach the sheets to the airframe, degrading the aircraft s airworthiness. Previous research developed a noninvasive technique for the evaluation of the material composition of aluminum surfaces, utilizing the information encoded in the energy spectra of Compton-scattered gamma emissions. The spectra are gathered by a six-element, high purity germanium detector array. A, first principles, deterministic computer code is used to reconstruct a two-dimensional map of the electron density of aluminum samples. Previous efforts, to image pure aluminum samples, …

Low Energy Implantation Of Boron With Decaborane Ions, Maria Angela Albano

Dissertations

The goal of this dissertation was to determine the feasibility of a novel approach to forming ultra shallow p-type junctions (tens of nm.) needed for future generations of Si MOS devices. In the new approach, B dopant atoms are implanted by cluster ions obtained by ionization of decaborane (B₁₀H₁₄)vapor. Each B atom carries only ~9% of the cluster kinetic energy and the B dose per unit charge is 10 times larger than in the case of monomer ion beams. Thus, the problems of spacecharge, limiting the extraction and transport of low energy (< = 1 keV) beams of B⁺ ions, can …

Observation Of Magnetic Moments In The Superconducting State Of Yba2⁢Cu3⁢O6.6, Herbert A. Mook, Pengcheng Dai, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Neutron scattering measurements for YBa_2⁢Cu_3⁢O_6.6 have identified small magnetic moments that increase in strength as the temperature is reduced below T* and further increase below T_c. An analysis of the data shows the moments are antiferromagnetic between the Cu-O planes with a correlation length of longer than 195 Å in the a-b plane and about 35 Å along the c axis. The origin of the moments is unknown, and their properties are discussed both in terms of Cu spin magnetism and orbital bond currents.

Observation Of Magnetic Moments In The Superconducting State Of Yba2⁢Cu3⁢O6.6, Herbert A. Mook, Pengcheng Dai, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Neutron scattering measurements for YBa_2⁢Cu_3⁢O_6.6 have identified small magnetic moments that increase in strength as the temperature is reduced below T* and further increase below T_c. An analysis of the data shows the moments are antiferromagnetic between the Cu-O planes with a correlation length of longer than 195 Å in the a-b plane and about 35 Å along the c axis. The origin of the moments is unknown, and their properties are discussed both in terms of Cu spin magnetism and orbital bond currents.

Anisotropy In The Electronic Screening Of Oxygen Lattice Modes In Yba2cu3o6.95, R. J. Mcqueeny, T. Egami, J.-H. Chung, Y. Petrov, M. Yethiraj, M. Arai, Y. Inamura, Y. Endoh, C. Frost, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Inelastic neutron scattering data from a twinned single-crystal of YBa₂Cu₃O_6.95 are presented that show a distinct a-b plane anisotropy in the oxygen vibrations. The Cu-O bond-stretching type phonons are simultaneously observed along the a and b directions due to a 4 meV splitting arising from the orthorhombicity. The present results show the bond-stretching branch along b (parallel to the chain) has a continuous dispersion, while the branch along a is discontinuous, suggesting a possibility of short-range cell-doubling along a. Furthermore, the LO mode along a is split in en ergy from its TO partner at …

Performance Of Proton Exchange Membranefuel Cell With Co/H2 Fuel, Hong-Mei Yu, Zhong-Jun Hou, Bao-Lian Yi, Ke-Wan Bi, Jing-Xin Zhang, Zhi-Yin Lin, Ming Han

Journal of Electrochemistry

Fuel of proton exchange membrane fuel cell(PEMFC) mostly comes from reformatecontains CO which will poison the fuel cell electrocatalyst. The effect of CO on the performance of PEMFC was studied in this paper. The results of the experiment show that when CO is fed inPEMFC ,the cell voltage will be decreased violently,then it will become steady with some vibration. The poison will become more serious with higher CO content and weaker at higher temperature. The adsorption of CO on the electrocatalyst is reversible. The PtRu electrocatalyst is moresuitable for the electrocatalysis of CO/H₂ than Pt electrocatalyst.

Atmospheric Corrosion Of Steels In China, Cai-Feng Liang

Journal of Electrochemistry

Data of eight year atmospheric exposures of 17 steels at 7 sites in China were analyzed. The result showed that the most detrimental pollution is sulfur dioxide and chloride ion for corrosion of carbon steels and low alloy weathering steels. This is in accordance with the common knowledge.The effect of sulfur dioxide is serious in the first few years and becomes weak obviously in the later years. The environment factor of humid hot is much more important in long run than the ordinarily acknowledged humidity, pollution for non weathering steels,although it is not obvious in the beginning. If pollution were …

Properties Of Metallized Polyo-Toluididemembrane Modified Electrode, Li-Zong Dai, Yi-Ting Xu, Hui-Huang Wu

Journal of Electrochemistry

The platinum particles were electrodeposited on poly(o-toluidide), POT, modified electrode, and the surface configuration and crystal orientation of Pt particles were investigated by SEM and XRD. At the same time the oxidation of isopropanol on platinized POT modified electrode was studied. The results indicate that Pt particles deposite towards preferred-orientation; moreover the increase in polymer electroactivity due to proton doping affects the dimension and graininess of deposited Pt particles. At the metallized polymer electrode the oxidation of isopropanol can occur in POT electroactive potential region, however at the more positive than 0.70 V (SCE) potential where POT loses redox activity …

Galvanic Corrosion Of Tin-W Electro-Couple During Tungsten Chemical Mechanical Polishing, Xuan Cheng, Chang-Jian Lin

Journal of Electrochemistry

Chemical mechanical polishing (CMP) is a process whereby mechanicaland chemical forces are combined to remove material from a wafer and polish it to a flatsurface. Tungsten CMP is an important prcess to gain the global planarity of siliconwafers with tungsten (W) plugs. Tungsten is actually deposited on a thin adhesive layerof titanium nitride (TiN) on silicon. When close to the final stage of polishing, TiN and W will be simultaneously exposed to the polishing chemistry, forming a galvaniccouple. The corrsion of TiN and W couple will result in different polish rate.

Electrochemical Behavior Of Tinicu Shape Memry Alloy In Simulated Body Fluid, Cheng-Hao Liang, Hong-Yan Sui

Journal of Electrochemistry

The study of TiNiCu shape memory alloys (SMA) in Hank's simulated body fluidwas carried out. The results showed that narrow passive range was found in acid environment andactive anodic dissolution was discovered at 100~150 mV vs SCE on anodic polarization cure ofTiNiCu SMA. Temperature had little effect on anodic polarization. With the decrease of pH andthe increase of Cl^- concentration ,pitting corrosion potential (E_b) shifted negatively. The electrochemical capability of TiNiCu SMA was inferior to that of TiNi SMA. Observations by means ofXRD and SEM indicate that TiNiCu SMA is not in single crystal structure, which caused …

Study Of The Oxidation Dynamics Of Tizro2 Metal-Ceramics, Wen-Chao Li, Li-Dong Teng

Journal of Electrochemistry

The oxidation dynamics of hot-pressed Ti-ZrO₂ metal-ceramics with the compositionof 50 vol.% Ti and 50 vol.% ZrO₂ has been studied.Thermodynamic analysis shows that Ticould react with O₂ but not with N₂ in the oxidizing process of TiZrO₂ composites at 0.1 MPa air. The oxidation dynamic behavior of Ti-ZrO₂ composites is analogous to that of pure Ti. Theactivation energy for the oxygen diffusion in Ti-ZrO₂ composites is higher than that in Ti solutions, for the presence of ZrO₂ restrains the oxygen diffusion in Ti-ZrO₂ composites. At early stagethe oxidation of Ti-ZrO_{2 …}

Preparation And Properties Of Separator For Lithium-Ion Battery, Xu-Mei Ren, Feng Wu, Chuan Wu, Han-Jun Li, Xue-Jie Huang

Journal of Electrochemistry

Lithium-ion batteries are well adapted to the new multimedia applications. PP/PE based microporous film is commonly used as separator in commercial lithium ion batteries. Herewe report a microporous film which is superior to the commercial available separator. The microporous PVDF polymer separators were prepared by the phase inversion process. The pore size of the separator is Φ 7 μm , and it's porosity is 75 %. The membrane in LiPF₆-EC/DEC showedhigh ionic conductivity (above 10^-3 S/cm at room temperature), and good mechanical properties(10³ kg/cm²). The half-cells consisted of Li/PVDF separator/MCMB showed excellent cyclingcharacteristics and …

The Effect Of Calcium On The Properties Of Molybdenum Nitride Electrode, Yun-Gui Zhu, Xue-Liang Li, Dao-Rong Lu, Jian-Bo He, Ji-Huai Xia

Journal of Electrochemistry

The effect of calcium on the properties of molybdenum nitride film electrode wasstudied by using XRD, SEM and cyclic voltammetry. The results show that the specific electriccapacity and the voltage operating range of electrode vary with the concentration of additive in thedipping solution. At the optimum concentration of additive in the dipping solution, the specificelectric capacity of the electrode is 2.1 times as large as that of the electrode prepared in the dipping solution without additive, and the voltage operating range of electrode is increased by 0.11 V. The active mechanism of calcium on the properties of film electrode suggested …

Corrosion Behavior Of Titanium In Fgd System, J-C Lin, T-L Chang, C-T Dung, S-L Lee, S-D Chyou, S-D Guo

Journal of Electrochemistry

In-situ corrosion test of titanium in flue gas desulfurization(FGD) system has been studied. Specimens of commercial Ti alloy have been put in four different locations (i. e , cooler, pre-scruber, absorber and heater) of the FGD system for 271 days. The corrosion rate is very low (i.e.<1 mpy) in all locations. Almost no corrosion can be found in the prescruber(0 mpy), but a sensible corrosion rate is estimated in the heater (0.58 mpy). Examination through SEM, all the specimens are subject to pitting corrosion except those in the prescruber. ESCA analysis indicates that the surface film for the specimen in prescruber is calcium carbonate, but titanium nitrate for the specimen in heater. Cyclic anodic potentiodynamic polarization (CAPP) of titanium in aerated and deaerated green solution provides an interpretation on the corrosion behavior of the titanium in the FGD system.

Performance Of A Direct Methanol Fuel Cell, Zhao-Bin Wei, Jian-Guo Liu, Ya-Guang Jiao, Wei-Jiang Zhou, Wen-Zhen Li, Li-Kang Chen, Qin Xin, Bao-Lian Yi

Journal of Electrochemistry

A direct methanol fuel cell with 9cm² active area consists of Pt-Ru/C anode ,Pt/Ccathode and Nafion 115 membrane. The effect of operating conditions: methanol solution concentration, oxygen pressure and cell temperature on the cell performances was investigated. The results show that performance of single cell was enhanced by increasing oxygen pressure and celltemperature ,and a maximum power density 75 mW/cm² was obtained in the range of 250-300mA/cm² current density, 0.2 MPa oxygen pressure, 1.0 mol/L methanol concentration and 75 ℃ cell temperature. When cell operating at room temperature, a relatively low, but a stable performance of cell …

Study On Corrosion Resistance Of Electroless Nickel Composite Coatings, Tsong-Jen Yang, Meng-Feng Jou

Journal of Electrochemistry

The eletroless nickel composite coating was prepared by uniform dispersion of diamond (or PTFE) particles throughout electroless nickel deposition. Corrosion resistance of composite coating in 3.5% NaCl aqueous solution was investigated by electrochemical analysis, dipping test and salt spray test. The results showed that the corrosion resistance of composite coating was inferior to that of electroless nickel coating if small amount of particles was added to the composite coating. Microsturctural analysis by SEM, AES, XRD, and EPMA indicated that the distribution of phosphorus is not homogeneous in the composite coating. The phosphorus_rich region acts as microcathode, however, the phosphorus-lean region …

Preparation Of Ti-Based Nanocrystalline Tio2 Film Electrode With High Activity, Dao-Bao Chu, Guang-Xia Shen, Xing-Fu Zhou, Chang-Jian Lin, Hua-Shui Lin

Journal of Electrochemistry

The potentiostatic electrosynthesis of Ti(EtO)₄ was studied by anodic dissolution of metal titanium(TA1) in solution of 0.005 mol·L^-1 (EtO)₄NBr in the ethanol (AR) in the presence negligible CH₃COCH₂COCH₃. The Ti-based nanocrystalline TiO₂ Film electrode (Ti/nano-TiO₂) was prepared by sol-gel method. By TEM, SEM and XRD, it has been shown that the anatase particle of TiO₂ was 10～35 nm in diameter and the film was 0.5 μm in thickness. The nanocrystalline film was composed of a three-diminsional network of interconnected particles. Reodx behavior and electrocatalytic activities of …

New Progress In Studies Of Lithium Nickel Oxide As Positive Electrode Materials Of Lithium Ion Batteris, Han-San Liu, Yong Yang, Zhong-Ru Zhang, Zu-Geng Lin

Journal of Electrochemistry

Lithium nickel oxide as the positive electrode of lithium ion batteries has aroused more and more interests.This paper reviews the recent reserches on synthesis and element-substitution of LiNiO₂ cathode material,and summarizes the intrinsical relationship between properties and sturcture of the material.The developments of new synthesis methods and mutilsubstitution of the material are expecting to be studied in the future research.

Electrochemistry Characteristic Of Carbon Steel Under Biofilm And Sulfide Film, Ze-Hua Dong, Xing-Peng Guo, Jia-Shen Zheng, Li-Ming Xu

Journal of Electrochemistry

Wire Beam Electrode (WBE) made of Q235 carbon steel was applied to study theheterogeneous corrosion beneath biofilm formed by Sulfate Reducing Bacteria (SRB) in cultureand sulfide film in solution with 1% NaCl and 300 mg/L⋅S^2-. The potential, galvanic density mapping, as well as polarization curve and Electrochemical Impedance Spectrum (EIS) were measured to predict the localized corrosion under biofilm and sulfide film. As a result, the mappingshowed the potential fluctuation on the WBE suface decreased over time due to the conductivityof the biofilm and sulfide film. Therefore, the potential mapping could not be a criterion of localized corrosion …

The Effect Of Preparation Condition On The Photoelectrochemical Performance Of Both The Pani Film And Tio2-Pani Composite Film On Au, Huai-Guo Huang, Hong-Ping Zhang, Zhi-Xin Zheng, Yan-Yan Xi, Ling-Ling Wu, Zhong-Hua Lin

Journal of Electrochemistry

Both the PANI (polyaniline) film and TiO₂-PANI composite film on the PATP(paminothiophenol)/Au substrate were obtained under different preparation condition by electrochemical methods, and their photoelectrochemical performances were alo studied. The resultsshowed that the photoelectrochemical performances of the films depend deeply on the comditionsof preparation. The self-assembling of PATP favors the adhesion of PANl. The partially-oxidizedPANI has a greater photoelectrochemical response than that of the reduced PANI and oxidized PANl. There is an optimum of film thickness for the photoelectrochemical performance of PANI film. Heat treating is in favor of the photoelectrochemical performance of TiO₂, but decreases …

Cluster Monte Carlo Simulations Of The Nematic--Isotropic Transition, Nikolai V. Priezjev, Robert A. Pelcovits

Mechanical and Materials Engineering Faculty Publications

We report the results of simulations of the three-dimensional Lebwohl-Lasher model of the nematic-isotropic transition using a single cluster Monte Carlo algorithm. The algorithm, first introduced by Kunz and Zumbach to study two-dimensional nematics, is a modification of the Wolff algorithm for spin systems, and greatly reduces critical slowing down. We calculate the free energy in the neighborhood of the transition for systems up to linear size 70. We find a double well structure with a barrier that grows with increasing system size. We thus obtain an upper estimate of the value of the transition temperature in the thermodynamic limit.

Studies On The Formation Of Dna-Cationic Lipid Composite Films And Dna Hybridization In The Composites, Murali Sastry, Vidya Ramakrishnan, Mrunalini Pattarkine, Krishna N. Ganesh

Faculty Works

The formation of composite films of double-stranded DNA and cationic lipid molecules (octadecylamine, ODA) and the hybridization of complementary single-stranded DNA molecules in such composite films are demonstrated. The immobilization of DNA is accomplished by simple immersion of a thermally evaporated ODA film in the DNA solution at close to physiological pH. The entrapment of the DNA molecules in the cationic lipid film is dominated by attractive electrostatic interaction between the negatively charged phosphate backbone of the DNA molecules and the protonated amine molecules in the thermally evaporated film and has been quantified using quartz crystal microgravimetry (QCM). Fluorescence studies …