Materials Science and Engineering Commons^™

Academic Integrity Among Engineering Undergraduates: Seven Years Of Research By The E3 Team, Cynthia J. Finelli, Trevor S. Harding, Donald D. Carpenter

Materials Engineering

The E³ Team (Exploring Ethical decision-making in Engineering) is a group of engineering educators and educational researchers who have worked collaboratively since 2000 to understand the underlying causes of academic dishonesty in engineering undergraduate populations. The team was especially motivated by decades of others’ work showing that, when surveyed, engineering students were among those most likely to report frequently cheating. This paper summarizes some of the team’s more important findings from three major studies that surveyed a total of 1300 engineering and humanities undergraduates at eleven institutions. The paper also describes the next phase of the team’s research and …

Exciting Students About Materials Science And Engineering: A Project-Based, Service-Learning Museum Design Course, Katherine C. Chen

Materials Engineering

A new course was developed for Materials Engineering students to design, create, and install interactive, educational displays on Materials Science & Engineering for a science museum at a local K-6 charter school. The course grew out of an ASM Foundation grant “to excite young people in materials, science, and engineering careers,” and the challenge was put forth to Cal Poly students. A formal design sequence was applied to give the students the opportunity to learn about the design process, project management, and teamwork. User profiles were created for the stakeholders, and project values were established. The class partnered with the …

A Design Methodology For Empowering Project-Based Learning, Richard N. Savage

Materials Engineering

One of our primary objectives is to equip undergraduate engineering students to be successful global engineers, ready to face the challenges of the 21st century. Students need to develop self-directed learning skills, systems level thinking, the ability to integrate principles of sustainability into design solutions and recognize that they serve a global community. Project-based learning (PBL) has been identified as an effective process for developing these skills; however, to be effective, project-based learning activities require a clearly articulated design methodology. Engineering students must learn to recognize the similarities and differences between the scientific and design methods. Both can be looked …

Experimental Investigation And Numerical Modeling Of Hybrid Glass/Carbon Frp Section Combined With Concrete Slab, Stephen Craig Raynor

Theses

No abstract provided.

Continuous Steel Production And Apparatus, Kent D. Peaslee, Jörg Peter, D. G. C. Robertson, Brian G. Thomas, Lifeng Zhang

Materials Science and Engineering Faculty Research & Creative Works

A process for continuous refining of steel via multiple distinct reaction vessels for melting, oxidation, reduction, and refining for delivery of steel continuously to, for example, a tundish of a continuous caster system, and associated apparatus.

Tuning Magnetic Microstructures Of Reference Layer In Magnetic Tunneling Junctions, L. Yuan, Y. S. Lin, Dexin Wang, Sy-Hwang Liou

Materials Research Science and Engineering Center: Faculty Publications

Magnetic microstructures in the reference layer in magnetic tunneling junctions (MTJs) are tuned by a reversal field under ambient conditions to investigate their effects on the magnetoresistance (MR) and the exchange coupling field (H_E) between the reference layer and the free layer. Magnetization changes in the reference layer can be probed by measuring minor MR loops. The results show the H_E of the minor MR loops versus the applied reversal field changes from negative to positive and crosses zero. These results can be explained by the magnetic inhomogeneities at the interface between anti-ferromagnetic/pinned-ferromagnetic layers, which causes the …

Ferromagnetic Multipods Fabricated By Solution Phase Synthesis And Hydrogen Reduction, Y. C. Sui, Y. Zhao, Sitaram S. Jaswal, Xingzhong Li, David J. Sellmyer

Materials Research Science and Engineering Center: Faculty Publications

A simple approach combining pyrolysis and hydrogen reduction is formulated for making ferromagnetic-branched nanostructures called Co multipods. The CoO multipods (branched nanostructures) were produced through the pyrolysis of cobalt-oleate in octadecane at 280 °C with the presence of oleic acid under the protection of pure nitrogen. The angles between the nearest arms are 90°. After the reduction of the branched CoO nanostructures in flowing hydrogen gas in a tubular oven at 290°C, the CoO is reduced to pure cobalt with hexagonal crystal structure and the branched shapes are retained. Anisotropic magnetic properties were found for cobalt multipods on silicon substrates.

Magnetization Reversal In Cubic Nanoparticles With Uniaxial Surface Anisotropy, Ralph Skomski, Xiao-Hui Wei, David J. Sellmyer

Materials Research Science and Engineering Center: Faculty Publications

The effect of surface anisotropy on the magnetization reversal in small magnetic particles is investigated. The model considers particles of cubic shape cut from a tetragonal crystal with cube faces in the (001) and equivalent planes. In particles having diameters of less than about 10 nm, the coercivity approaches the Stoner–Wohlfarth limit, but the anisotropy field differs from that of the bulk of the particles. With increasing particle size, the nucleation modes acquire the character of magnetic surface or bulk modes that reduce the coercivity.

Effective Demagnetizing Factors Of Complicated Particle Mixtures, Ralph Skomski, George C. Hadjipanayis, David J. Sellmyer

Materials Research Science and Engineering Center: Faculty Publications

Demagnetizing factors have been calculated for hierarchical mixtures and dispersions of magnetic particles, such as columns of platelike particles in a matrix and clusters of spherical particles. The theory involves a number of shape and density parameters describing particles, aggregates, and matrix. It approximates distant particles by a homogeneous medium and yields closed and easy-to-use expressions for the effective demagnetizing factor.

Continuous/Cluster-Pinned Recording Media, Ralph Skomski, M. L. Yan, Yinfan Xu, David J. Sellmyer

Materials Research Science and Engineering Center: Faculty Publications

We propose and theoretically investigate a new class of nanostructured magnetic recording films, cluster-pinned recording media. The films consist of magnetic clusters exchange coupled to a continuous hard layer with perpendicular anisotropy and low coercivity. Our calculations yield the coercivity and the cross-track correlation length as a function of film thickness and pinning density and strength. The mechanism is very similar to the Gaunt–Friedel pinning in bulk magnets, which differs from ordinary strong pinning by the selfconsistent dependence of wall curvature and coercivity on defect concentration. The main difference is the exponent for the coercivity as a function of the …

Effect Of Prior Aging On Fatigue Behavior Of Im7/Bmi 5250-4 Composite At 191°C, Christine G. Ladrido

Theses and Dissertations

IM7/BMI 5250-4 with carbon fiber orientations [± 45] and [0/90] were aged in air at 191 °C for up to 1000 hours. The weight loss was analyzed during the aging process. Tension to failure tests were performed on both the unaged and aged specimens to establish a baseline for the Ultimate Tensile Strengths and Young's Modulus. Tension-tension cyclic load fatigue testing was conducted on the specimen to determine the effect of prior aging on the fatigue response of the composite. Cyclic strain accumulation was not influenced by prior aging, but it was influenced by the stress levels applied. [± 45] …

High Temperature Degradation Of 5250-4 Polymer Resin, Patrick E. Link

Theses and Dissertations

5250-4 bismaleimide resin is used in high performance polymer matrix composites with high temperature aeronautical applications. This thesis investigated the thermal and oxidative degradation of 5250-4 neat resin powder in argon, air, and oxygen environments. The powder was aged at 163 deg. C, 177 deg. C, and 190 deg. C in all environments for at least 250 hours. Isothermal thermo-gravimetric analysis demonstrated that weight loss was negligible for aging in the argon environment, indicating weight loss is the result of an oxidative process at these temperatures. The 5250-4 powder exhibited an initial period of weight gain before eventually losing weight …

Development Of Knowledge Base Of Concrete Bridge Maintenance System, Bahre Karam

Masters Theses

Bridges are the key elements of any transportation system of a country. Bridges are expensive structures and therefore, it's essential to maintain and repair them on regular basis. Almost one third of the bridges in United States are reported to be in some what deteriorated conditions. This Research presents the development of knowledge base for decision support system for concrete bridges.

During this research various concrete bridge problems are investigated including COlTosion, delamination, cracks, spalling and scour etc. The inspection tools and techniques are addressed in order to identify these problems both for above and below water surface. The various …

The Effect Of Cold Work On The Mechanical Behavior Of Niti Shape Memory Alloys, Mohamed Elwi Mitwally

Archived Theses and Dissertations

No abstract provided.

Formation Of Rdx Nanoparticles By Rapid Expansion Of Supercritical Solution : In Situ Characterization By Laser Scattering, Takuya Matsunaga

Dissertations

Cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), a well-known energetic material, is highly explosive. Reduction of the sensitivity of RDX is desired for safe handling and

storage in military applications. Data on the sensitivity of RDX in the 10-1000 µm crystal size range suggested that the impact sensitivity could be further reduced by reduction of the crystal size to the sub-micron or nano-scale (Armstrong, 1990). Recent research with nano-RDX obtained using Rapid Expansion of Supercritical Solutions (RESS) confirmed these expectations (Stepanov, 2005).

RESS process appeared to be one out of a few techniques of production of nanoscale energetic materials free of the risk of explosion. …

Catalysis Of Nano Tio2 For Horseradish Peroxidase, Ya-Qi Zhu, Hai Wu, Hiu Liu, Jie Ma

Journal of Electrochemistry

Horseradish peroxidase immobilized on the surface of titanium dioxide nanoparticles and nanotube modified glassy carbon electrode.The HRP direct electron transfer reaction was compared between TiO₂ nanoparticles and nanotube GC electrode.The results demonstrated that the HRP on TiO₂ nanotube /GC electrode could catalyze electron exchange reaction between electroactivity center of HRP and electrode.And the research of antibody labeled HRP provides a selected signal for antibody-antigen immunoassay.

Electrochemical Reduction Of Coals And The Oxygenic Functional Simulacrums Of Coals, Juan Lin, Zhao Wei

Journal of Electrochemistry

Electrochemical reduction of coals and the oxygenic functional simulacrums of coals has been studied.In this process,tetrabutylammonium was used as supporting electrolyte.The coal and the deoxidized coal were extracted by methanol.Qualitative analysis of the deoxidized products and the extractives was carried out on gas chromatograph-mass spectrometer.The deoxidized products of the oxygenic functional simulacrums of coals were analysed quantitatively with gas chromatograph spectrometer.The results show that the oxygenic functional groups on the coals surface decrease and the translation ratios of the oxygenic functional simulacrums of coals need further increase after electrochemical reduction,.The electrochemical tests show simultaneously the kinetics equations of every related …

Study On The Electricity Capability Of Ru((0.4-X))IrXTi(0.6)/Ti Electrode, Ling-Li Wang, Qiao Peng

Journal of Electrochemistry

The metal oxide anode of Ru_(0.4-x)Ir_xTi_0.6 has been prepared by thermal decomposition.The results indicate that,when the percent of IrO₂ is 10%,the electrode has low chlorine potential,high oxygen potential and excellent catalyze selectivity;strengthen life is long with IrO₂ content increased from 1.0h to 97h.It shows that the electrode anti-oxide corrosion perform is improved and intensifying life is long with addition of IrO₂.The film and reaction resistance are all fall with the addition of IrO₂.The addition of IrO₂ is in favor of thin crystal and makes the film more roughness.

Study On The Characteristics Of Vb(12) Modified Electrode By Electropolymerization, Hui-Ting Lian, Wen-Ji Wang

Journal of Electrochemistry

Preparation of the VB₁₂ modified electrode and its electrochemical characteristics were studied.The results showed that the VB₁₂ after electroactivated is able to electopolymerize on the GC by cyclic voltammetry(CV)in the DMSO solution.Differential pulse voltmmetry(DPV)showed that the VB₁₂ catalyzed the oxidation of NO₂^-,SO₃^2-and NH₂NH₂.The catalytic peak for NO₂^-on the modified electrode was observed at 0.76V(vs.SCE),but on the unmodified GC which at 1.0V.The catalytic currents increased linearly with the concentration of NO₂^-from 1.6×10^-6 to 4.3×10^-4 mol·L^-1 with a correlation coefficient …

Determination Of Ddopamine And Ascorbate On Gold Nanoparticle And 4,4-Bis (Methanethiol) Biphenyl (Mtp) Self-Assembled Monolayer Modified Gold Electrode, Hai-Yan Wang, Peng Liu, Ye Wang, Bao-Kang Jin

Journal of Electrochemistry

A new approach to construct an ampermetric biosensor was described.The 4,4-bis(methanethiol)biphenyl(MTP)is adsorbed on to a bare gold electrode to make self-assembled monolayers(MTP/Au SAMs).Then electrodeposited 2mg/mL HAuCl₄ at-200 mV,NG/MTP/Au electrode was prepared.When a differential pulse voltammetric(DPV)technique was used,the peak separation between DA and AA is 155 mV.Hence,the selective determination of dopamine(DA)and ascorbate(AA)in the binary mixture system can be performed.Under the chosen conditions,the peak currents are correspondent linearly to the concentrations of DA and AA in the range of 5.0×10^-7~1×10^-4 mol·L^-1 and 3.5×10^-6~1.0×10^-3mol·L^-1,respectively.The correlation coefficients were 0.998.The detection limit were 1.5×10 …

Corrosion Electrochemical Behavior Of Aluminum Flake Pigmented Water-Borne Epoxy Coating On Carbon Steel In Nacl Solution, Li-Li Xue, Li-Kun Xu, Qing-Fen Li, Hong-Qing Song, Wen-Juan Zhou, Guang-Zhang Chen

Journal of Electrochemistry

The corrosion electrochemical behavior of a water-borne epoxy coating pigmented with aluminum flake on carbon steel with artificial scratch defect was studied in 3.5% NaCl solution using electrochemical impedance spectroscopy(EIS)and scanning vibrating electrode technique(SVET).The results indicated that the defect presented anodic electroactivity at the initial stage of immersion,which extended gradually with time from the scratch into the neighboring coating,lowering the coating impedance.With further immersion,however,the electroactivity of the coating/steel interface decreased significantly due to the self-repairing of the corrosion products,causing an obvious increase of the coating impedance.In the later period of immersion,more scattered electroactive areas appeared under the coating because of …

Template Synthesis And Electrochemical Studies Of Ag(Core)Au(Shell) Nanowires, Li Ling, Ya-Xian Yuan, Min-Min Xu, Jian-Lin Yao, Ren-Ao Gu

Journal of Electrochemistry

Agcore Aushell nanowires with different thicknesses were prepared by combining template synthesis and chemical reduction method,and characterized by SEM and cyclic voltammetry(CV).The CV results revealed that the AgcoreAushell nanowires with pinhole were transferred to pinhole free structure after several potential scans.By using thiophenol(TP)and p-aminothiophenol(PATP)as probe,the surface enhanced Raman scattering(SERS)effect was investigated on the core-shell nanowires.The results indicated that AgcoreAushell nanowires could be served as a potential SERS substrate,and the difference in the spectral feature of PATP adsorbed onto Au and Ag nanowires enable us to diagnose the pinhole effect of core-shell nanowires by SERS.

Electricity Generation From A Microbial Fuel Cell Employing Desulfovibrio Salexigens, Ping Ding, Hai-Bo Shao, Guang-Zhou Liu, Dong-Xia Duan, Ting Ma, Si-Jun Chen, Jian-Ming Wang, Jian-Qing Zhang

Journal of Electrochemistry

A microbial fuel cell of laboratory scale employing Desulfovibrio salexigens in lactate based seawater substrate was proposed.Electricity was continuously harvested after inoculation.During 20 days of fermentation/discharge,COD values of the substrate decreased by 61.7%,in which 9.81% was converted to electricity.

The Research Of Several Electrodes For Spe Water Electrolysis, Jian-Bo Meng, Ge Sang, Yan Xue, Wei Cao, Xiao-Qiu Ye

Journal of Electrochemistry

Performances of the IrRu/Nafion 117/PbAg,IrRu/Nafion 117/Ni,IrRu/Nafion 117/TiNi,Ag/Nafion 117/Ni and C/Nafion 117/PtRu for the SPE water electrolysis have been investigated.The order of the electrocatalysis activity for the anodic electrodes as mentioned above is IrRu>Ag>C,and that of cathodic electrode is Ni>PbAg>TiNi.While the stability of TiNi was much better than Ni,and that of PbAg is best.Moreover,the current efficiency was raised with the increase of current density.

Study On The Contribution Of Cobalt Additives To Foam Nickel Electrodes, Xiao-Feng Li, Tong-Chi Xia, Shao-Peng Yi, Xiu-Juan Gu, Yu-Lin Song

Journal of Electrochemistry

Two incorporation ways of the cobalt additives into foam nickel electrodes,i.e.the co-precipitated and admixed method are used.The results of X-ray diffraction(XRD),cyclic voltammetry,electrochemical impedance spectrum(EIS)and galvanostatic charge-discharge curves show that(Ⅰ)there is a decrease in intensity and increase in half peak breadths of the diffraction peaks of Ni(OH)₂ with co-precipitated cobalt additive;(Ⅱ)the electrochemical activity of nickel hydroxide can be improved by both incorporation ways and the effect of admixed CoO is more notable;(Ⅲ)β-CoOOH derived from admixed CoO is not stable at lower potential,thus results in an irreversible capacity loss of nickel-metal-hydride(Ni-MH)battery after imposed overdischarged-state storage.

Determination Of Tetracyclines Based On The Flow-Through Electrochemical Detection Cell With Nickel Electrode, Dan-Mei Pan, Rong-Zong Hu, Dong-Ping Wei, Hao-Dong Ding

Journal of Electrochemistry

The electrochemical responses to tetracycline at the nickel electrode in alkaline solution were compared with that of gold and glassy carbon electrode by voltammetry.The electrocatalytic oxidation characteristics of tetracycline at nickel electrode were discussed.Subsequently a flow-through amperometric detection cell with nickel as the working electrode was designed to detect tetracycline,oxytetracycline,and doxycycline.Standard calibration graphs for the tetracyclines yielded linear ranges of 0.1~15 mg/L.Detection limits(S/N=3)of 35,45 and 43 μg/L were obtained for tetracycline,oxytetracycline and doxycycline,respectively.The system was applied for the determination of the three antibiotics in single-component drug formulations.

Study On The Electrogeneration And Properties Of Superoxide Ion In Aprotic Media By Using Carbon Nanotubes Powder Microelectrode, Ying-Liang Wei, Chen Shao, Hui Feng

Journal of Electrochemistry

Multi-wall carbon nanotubes are filled in the cavity at the tip of a microelectrode to form a carbon nanotubes powder microelectrode(CNTs-PME).The CNTs-PME is used to study the electrochemical reduction of oxygen in aprotic media.It is a nearly reversible redox process of the O₂/O₂^- couple at the CNTs-PME in the dimethyl sulfoxide(DMSO)solution.The heterogeneous electron transfer rate constant(ks)can be measured by steady-state voltammogram and the result is 9.8 10^-3cm /s.As a weak oxidant,the reaction of O₂^- with epinephrine was studied by cyclic voltammetry.Additionally,the reaction of O₂^- with benzoic acid was also discussed …

Square Wave Stripping Voltammetric Behaviors Of Actinomycin D On Glod Electrode And Its Application, Qing-Tao Zhu, Fang Liao, Xiao-Ying He

Journal of Electrochemistry

The electrochemical behaviors of Actinomycin D(ACTD)at glod electrode were investigated by square wave stripping voltammeter in the KH₂PO₄-Na₂HPO₄ buffer solution(pH=5.90).The sensitive oxidation peak of ACTD was observed and the potential peak for ACTD is-0.17 V(vs.SCE).The Experimental parameters,such as pH value,amplitude,accumulation potential and time were optimized,and a direct electroanalytical method for determining ACTD was developed.The peak currents were proportional to the concentration of ACTD in the range of 0.1μmol·L^-1～10.0μmol·L^-1,and the linear regression coefficient equaled 0.9991.The detection limit for ACTD was 1.0×10^-8mol·L^-1.

Voltammetric Behavior And Electrocatalytic Properties Of Hemoglobin At Glassy Carbon Electrode Modified With Lauric Acid, Xin-Rui Miao, Xu-Hong Zhang, Ying Xie

Journal of Electrochemistry

The electrochemical behavior of hemoglobin at glassy carbon(GC)electrode modified with Lauric Acid was studied.In the potential of +0.6～-0.7 V(vs.Ag/AgCl),an irreversible cathodic peak was observed at-0.3 V at the scan rate of 20 mV·s^-1.In the medium of 0.02 mol·L^-1 KH₂PO₄-Na₂HPO₄(pH 7.0),ip increased with the increasing concentration of Hb and the value of pH.The peak currents were proportional to the concentrations of hemoglobin in the range of 1.00×10^-8～5.00×10^-9 mol·L^-1 and 1.92×10^-6～2.06×10^-7 mol·L^-1.The data was analyzed in details by simulating in order to …

Modification Of Electrolytic Manganese Dioxide, Shu-Rong Ding, Xin-Hai Li, Zhi-Xing Wang, Hua-Jun Guo

Journal of Electrochemistry

The EMD samples coated with CMD-Bi compound were prepared by liquid-phase surface treatment method.XRD and SEM research indicated that the modified manganese dioxide, i.e, EMD/CMD-Bi, could keep γ-MnO₂ crystal structure of EMD and had more pores on its surface with an obvious floccule layer.Electrochemical test indicated that the second electron reduction peak current increased by 1.5 times and the discharge capacity increased by 40.8% and 78.3% respectively than that of pure EMD electrode under the condition of-0.8 V(vs.Hg/HgO) cut-off voltage at 30.8 mA/g and 102.7 mA/g current density.