Engineering Science and Materials Commons^™

Basic Principles And Applications Of Secm In Metal Corrosion, Fa-He Cao, Yan Xia, Wen-Juan Liu, Lin-Rong Chang, Jian-Qing Zhang

Journal of Electrochemistry

Scanning electrochemical microscopy (SECM) is chemical microscopy with higher spatial resolution. After 24 years of development, SECM has been widely applied in mapping and kinetics study of heterogeneous electron transfer in localized processes at solid-liquid or liquid-liquid interfaces. The fundamentals and recent advances of SECM in corrosion applications are described, including SECM mapping and kinetics on localized corrosion of metal or coating. Research work of SECM in corrosion by our group is also introduced. Future applications of SECM in corrosion are highlighted.

A Comparative Study In Pretreatments Of Acid Chemical Wastewater By Electrochemical Oxidation And Ozonation, Han-Shui Liu, Su Yu, Shao-Ping Tong, Chun-An Ma

Journal of Electrochemistry

Under the condition of keeping certain acidity, the pretreatment efficiency of an acid chemical wastewater (pH 0.85) by electrochemical oxidation was compared with that by ozonation. The results showed that the electrochemical oxidation pretreatment could obtain a better result than the ozonation at pH 0.85. After the addition of 2 g·L^-1 NaCl and with the electrochemical oxidation pretreatment at 30 mA·cm^-2, the removal rate of chemical oxygen demand (CODCr) reached 43.4%, and the value of biochemical oxygen demand/chemical oxygen demand (BOD₅/COD_Cr) also increased from 0.034 to 0.14 in 20 minutes, indicating significantly improvement …

Applications Of Spectroscopic Ellipsometry In Corrosion Investigation, Ling-Jie Li, Yu-Ling He, Jing-Lei Lei, Sheng Tao Zhang

Journal of Electrochemistry

As a highly-sensitive and non-destructive in situ technique, spectroscopic ellipsometry has been widely applied in corrosion investigation to acquire the dynamic information of the “electrode-medium” interface during corrosion. This paper lays out some representative demonstrations in several established optical models used to interpret data obtained with spectroscopic ellipsometry in corrosion investigation. In addition, the latest trends in development of this technique are analyzed.

Corrosion Behavior Of Zinc Covered With Thin Electrolyte Layers Under External Electric Field, Xu-Jie Yuan, Jun-Xi Zhang, Shi-Ming Zhang, Tian Tan, Qi-Meng Chen

Journal of Electrochemistry

The corrosion behavior of zinc covered with thin electrolyte layers (TELs) under an application of external electric field was investigated by performing corrosion potential and cathodic polarization current measurements. The results showed that the Ecorr and ic values first increased and then decreased with the increase of electrolyte layer thickness. Pure zinc exhibited the maximum corrosion potential as the TELs increased to 400 μm under the controls of cathodic process and corrosion products. The application of external electric field resulted in either a negative shift in corrosion potential of zinc or an increase of cathodic current. The effect of external …

Experimental Design Methodology Applied To The Oxidation Of Quinolines In Aqueous Medium By Electro-Fenton Process, Souissi Souhaila Trabelsi, Nihal Oturan, Nizar Bellakhal, Mehmet A. Oturan

Journal of Electrochemistry

The degradation behavior of 8-hydroxyquinoleine sulfate (8-HQS), a model molecule of quinolines, was studied in an aqueous medium by electro-Fenton process using a carbon felt cathode and a platinum anode. The great oxidation ability of this process is due to a large production of hydroxyl radical (OH) by electrochemically induced Fenton’s reagent (H2O2, Fe2+). Hydroxyl radicals are very powerful oxidizing agents which react on organics up to complete mineralization. A factorial experimental design was used for determining the operating parameters on the degradation of 8-HQS in an aqueous medium. The results showed that the current intensity and the initial concentration …

Designing Meaningful Molecular Dynamics (Md) Simulations: The Lithiation Of Silicon, María Camila Rincon, Alejandro Strachan, Hojin Kim, David Guzman, Mathew Cherukara

The Summer Undergraduate Research Fellowship (SURF) Symposium

Molecular dynamics (MD) is used to understand the properties of materials by following the time evolution of the system and exploring the interactions between its constituent atoms. MD simulation allows making reliable predictions of various properties of materials; however, designing useful computer experiments is a complex task that requires the appropriate selection of interatomic interactions (force fields) and other conditions. In this work we discuss some aspects of molecular dynamics that would help the inexperienced users design reliable simulations. The simulation of the lithiation process of silicon is taken as an example for better understanding.

Compression Testing And Failure Modes Of Steel-Concrete Composite (Sc) Structures For Nuclear Containment, Patrick Michael Wanamaker, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Although being able to provide much cleaner power than burning coal and other fossil fuels, nuclear power plants are still a tough sell to the general public due to their history of being spontaneously dangerous. The containment structures surrounding these nuclear plants, however, can play a huge role in reducing the risks associated with them. Relatively new designs for these containment assemblies, known as SC (steel-concrete composite) structures, aim to increase the strength and durability of the containment facilities while keeping costs down. By varying the spacing between shear studs, the ratio of concrete to steel, and the ratio of …

Code Optimization For Phase Field Method, Sergio Andres Monsalve, Marisol Koslowski

The Summer Undergraduate Research Fellowship (SURF) Symposium

The Phase field model method for studying grain dislocation at atomic level after applying an external force to the materials being tested, enables simulate the behavior of different materials after applying stress. With the appropriate numerical method the simulation could change drastically the complexity of the algorithm. Finding the most accurate and stable numerical method for the phase field model give us a considerable improving in the performance of the code used to simulate the phase field dynamic dislocation in larger and more complex simulations can be performed. We made an statistic comparison between the different methods, comparing stability and …

Evaluation Of Phase Change Materials For Cooling In A Super-Insulated Passive House, Jeffrey Stephen Lauck

Dissertations and Theses

Due to factors such as rising energy costs, diminishing resources, and climate change, the demand for high performance buildings is on the rise. As a result, several new building standards have emerged including the Passive House Standard, a rigorous energy-use standard based on a super-insulated and very tightly sealed building envelope. The standard requires that that air infiltration is less than or equal to 0.6 air changes per hour at a 50 Pascal pressure difference, annual heating energy is less than or equal to 15kWh/m2, and total annual source energy is less than or equal to 120 kWh/m2. A common …

Calculation Of Colouration Voltage For A Multifunctional Glazing Powered By Photovoltaic, Aritra Ghosh, Brian Norton, Aidan Duffy

Conference papers

Multifunctional glazing is a combination of various glazing systems and can comprise permutations of vacuum glazing, aerogel glazing, PV double glazing and Electrochromic (EC) glazing. It controls solar heat gain, improves thermal conductivity and can generate small scale electricity, in a variety of climates. The objective of this research is to investigate the switching voltage of multifunctional glazing, with respect to orientation, time of day and temperature of the system. We report a relation between temperature and voltage required for the switching condition.

Design And Assembly Of Nanostructured Complex Metal Oxide Materials For The Construction Of Batteries And Thermoelectric Devices, Gautam Ganapati Yadav

Open Access Dissertations

Thermoelectric devices and lithium-ion batteries are among the fastest growing energy technologies. Thermoelectric devices generate energy from waste heat, whereas lithium-ion batteries store energy for use in commercial applications. Two different topics are bound with a common thread in this thesis - nanotechnology! In fact, nanostructuring is a more preferred term for the approach I have taken herein. Another commonality between these two topics is the material system I have used to prove my hypotheses - complex metal oxides.

Complex metal oxides can be used for both energy generation and storage as they are stable at high temperatures, are benign …

Fabricating Complex-Shaped Components By Room-Temperature Injection Molding Of Aqueous Ceramic Suspension Gels, Valerie Lynn Wiesner

Open Access Dissertations

Water-based ceramic suspension gels (CeraSGels) effectively produced dense, near-net shape ceramic parts by room-temperature injection molding, a novel processing method based on traditional ceramic injection molding. This alternative method eliminated the need for heating and cooling feedstocks to process, as is required in conventional injection molding, through control of the rheological response of the CeraSGels by simply varying polymer content without the use of any harsh crosslinking or curing agents or further chemical processes. The development of room-temperature injection molding initially focused on forming CeraSGels based on alumina, a readily available model material, in order to optimize suspension preparation and …

Preparation Of Mesoporous Silica Supported Ruthenium Oxides And The Application And Kinetic Study In The Catalysis Of Water Oxidation, Yang Zhang

Open Access Dissertations

Photo-induced water splitting of water into H2 and O2 has been a major focus in the development of clean and renewable energy. The development of viable and efficient catalysts that facilitates O2 production remains the major challenge in the study of the corresponding half-reaction of water oxidation. There are plenty of metal oxides reported active in the catalysis of water oxidation. However, several important performance bench marks of those materials, such as the non-stoichiometric production of O2, slow reaction rate and/or low quantum efficiency, remain to be improved.

Ruthenium oxide (RuO2) has long been known as one of the most …

A New Angle On Microscopic Suspension Feeders Near Boundaries, Rachel E. Pepper, Marcus Roper, Sangjin Ryu, Nobuyoshi Matsumoto, Moeto Nagai, Howard A. Stone

Department of Mechanical and Materials Engineering: Faculty Publications

Microscopic sessile suspension feeders are a critical component in aquatic ecosystems, acting as an intermediate trophic stage between bacteria and higher eukaryotic taxa. Because they live attached to boundaries, it has long been thought that recirculation of the feeding currents produced by sessile suspension feeders inhibits their ability to access fresh fluid. However, previous models for the feeding flows of these organisms assume that they feed by pushing fluid perpendicular to surfaces they live upon, whereas we observe that sessile suspension feeders often feed at an angle to these boundaries. Using experiments and calculations, we show that living suspension feeders …

Modeling The Impact Of Simulated Educational Interventions On The Use And Abuse Of Pharmaceutical Opioids In The United States: A Report On Initial Efforts, Wayne Wakeland, Alexandra E. Nielsen, Teresa D. Schmidt, Dennis Mccarty, Lynn Webster, John Fitzgerald, J. David Haddox

Systems Science Faculty Publications and Presentations

Three educational interventions were simulated in a system dynamics model of the medical use, trafficking, and nonmedical use of pharmaceutical opioids. The study relied on secondary data obtained in the literature for the period of 1995 to 2008 as well as expert panel recommendations regarding model parameters and structure. The behavior of the resulting systems-level model was tested for fit against reference behavior data. After the base model was tested, logic to represent three educational interventions was added and the impact of each intervention on simulated overdose deaths was evaluated over a 7-year evaluation period, 2008 to 2015. Principal findings …

Metal-Assisted Etching Of Silicon Molds For Electroforming, Ralu Divan, Dan Rosenthal '14, Karim Ogando, Leonidas E. Ocola, Daniel Rosenmann, Nicolaie Moldovan

Student Publications & Research

Ordered arrays of high-aspect-ratio micro/nanostructures in semiconductors stirred a huge scientific interest due to their unique one-dimensional physical morphology and the associated electrical, mechanical, chemical, optoelectronic, and thermal properties. Metal-assisted chemical etching enables fabrication of such high aspect ratio Si nanostructures with controlled diameter, shape, length, and packing density, but suffers from structure deformation and shape inconsistency due to uncontrolled migration of noble metal structures during etching. Hereby the authors prove that a Ti adhesion layer helps in stabilizing gold structures, preventing their migration on the wafer surface while not impeding the etching. Based on this finding, the authors demonstrate …

The Role Of Mechanically Induced Erk Phosphorylation In Stem Cell Adipogenesis, Daniel E. Menter

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Mechanical cell stimulation has only recently been highlighted for its ability to direct cell function and fate. The development of techniques to apply controlled mechanical stimulation to cells has allowed researchers to examine the effects of forces on cell behavior. These studies have shown that cells, and in particular, stem cells are very sensitive to mechanical stimuli. While the potential impact of mechanical forces has been demonstrated by these studies, there have not been many studies that compare the differing effects of stimulation profiles and methods. Further, molecular mechanosensing mechanisms have not been identified. In this work, we compared the …

Me-Em Enewsbrief, September 2013, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical Engineering-Engineering Mechanics eNewsBrief

No abstract provided.

Finite Element Analysis Of The Ramberg-Osgood Bar, Dongming Wei

Dongming Wei

In this work, we present a priori error estimates of finite element approximations of the solution for the equilibrium equation of an axially loaded Ramberg-Osgood bar. The existence and uniqueness of the solution to the associated nonlinear two point boundary value problem is established and used as a foundation for the finite element analysis.

Collaborative Research: Mechanics Of Growing Bodies: A Riemannian Geometric Approach, Alireza Shamsaei Sarvestani

University of Maine Office of Research Administration: Grant Reports

The research objective of this grant is to elucidate a differential/Riemannian geometric formulation for the mechanics of growing bodies. The proposed work is based on the concept of a changing material manifold whose dynamics predicts the evolution of the relaxed state of a material body. This theory is applicable to biological tissues in which growth and remodeling are coupled with large deformations. To achieve the research objective of this proposal, a theory of continuum mechanics based on a dynamic material manifold is introduced that couples the growth/remodeling of biological tissues with their large deformations. The proposed research will put growth …

Advanced Treatment Of Dyeing Wastewater For Reuse By Electrochemical Oxidation, Fei-Xiang Chen, Chu-Yin Yang, Ming-Ming Zhou, Jia-De Wang

Journal of Electrochemistry

In response to the characteristics of dye wastewater, the electrochemical oxidation of effluents from the biochemical process of dyeing wastewater was studied in the electrochemical reactor using PbO₂/Ti electrode as the anode and stainless steel plate as the cathode. The results revealed that the electrochemical oxidation could simultaneously remove the Chemical Oxygen Demand (COD), ammonia and chromaticity. At the residence time of 60 min and current density of 10 mA·cm^-2, the COD, ammonia, chromaticity, concentration of chloride ion and pH values could meet the water standards for “the reuse of urban recycling water-water quality standard for …

Electrochemically Switched Ion Exchange Properties Of Pani-Snp Composite Films In Wastewater Containing Ni2+ And Cd2+, Yan-Ting Feng, Jun-Qiang Xiao, Xiao-Gang Hao, Xu-Li Ma, Zhong-De Wang, Nian-Chen Han

Journal of Electrochemistry

Electroactive PANI-SnP composite films were prepared by drop-coating method on Pt electrodes and investigated as electrochemically switched ion exchange (ESIX) materials for the separation of Cd²⁺ from aqueous solutions. The composition and morphology of the composite film were characterized by Fourier transform infrared spectrometer (FTIR) and scanning electron microscope (SEM). In solutions containing 0.1 mol·L^-1 Ni(NO₃)₂ and Cd(NO₃)₂, cyclic voltammetry (CV) and electrochemical quartz crystal microbalance (EQCM) were used to investigate the electrochemical behavior and ion-exchange mechanism of PANI-SnP composite film. The elementary composition of PANI-SnP composite films in both oxidation …

Research Progress Of Intermediate Layers In Ti-Based Oxide Anodes, Xiu-Li Song, Hui-Min Yang, Zhen-Hai Liang

Journal of Electrochemistry

Titanium (Ti)-based oxide anodes are excellent anode materials which have been applied widely in electrochemical fields all over the world. Adding intermediate layers in Ti-based oxide anodes can improve the conductivity, lengthen the lifetime and strengthen the stability between Ti base and metal oxides active layers of electrodes. This article reviews the research progress of intermediate layers in Ti-based oxide anodes. At the same time, current problems existed in the field of Ti-based oxide anodes are pointed out and future development trend in oxide electrode with intermediate layers is prospected.

Using Hydrolyzed Sludge Liquor As The Substrate Of Microbial Fuel Cell, Liang Peng, Guo Chao, Huang Xia

Journal of Electrochemistry

Hydrolyzed sludge liquor was used as the substrate of microbial fuel cell. When the thermal treatment time increased from 2 h to 96 h, pH varied little between 7.4 and 8.0. When the treatment time increased, the conductivity, COD and alkaline condition increased to 2.53 mS·cm^-1, 2520 mg·L^-1 and 800 mg·L^-1, respectively. Meanwhile, the power density increased to 25 W·m^-3. The COD removal increased firstly, then decreased, and finally reached the maximum of 47% at the hydrolyzed time of 6 h. The maximal coulombic efficiency was 71% when the treatment time was 4 …

Electrosynthesis Of Glycerol Carbonate From Co2 And Glycerol, Huan Wang, Mei-Xia Zhu, La-Xia Wu, Xiao-Ming Xu, Xue-Ru Zhao, Jia-Xing Lu

Journal of Electrochemistry

Glycerol carbonate was obtained from glycerol and carbon dioxide under room temperature and normal pressure by electrochemical method. The effects of synthesis conditions, such as cathode, charge, current density and temperature, on the reaction of glycerol and carbon dioxide have been investigated. The yields of 73% were produced by electrosynthesis of carbonate under the optimized condition, which is much higher than that by common catalysis method. The electrochemical behavior of the reaction system has been studied by cyclic voltammetry, through which the reaction process has been proposed.

Effects Of Fluoroethylene Carbonate Additive On Low Temperature Performance Of Li-Ion Batteries, Feng-Ju Bian, Zhong-Ru Zhang, Yong Yang

Journal of Electrochemistry

The effects of fluoroethylene carbonate (FEC) on the low temperature performance of lithium ion phosphate full battery are evaluated by different techniques. By addition of 5 wt% FEC into a commercial electrolyte, effective solid electrolyte interface (SEI) film can be formed on the graphite electrodes, the discharge capacity retention at -40 ^oC was increased from 31.7% to 43.7%, and the discharge voltage plateau of the cell is raised. This is attributed to a reduced charge transfer resistance and a lowered polarization on the graphite electrode by electrochemical impedance spectroscopy (EIS) and reference electrode test.

Electrochemical Behavior And Content Determination Of Paeonol At Poly Sudan Ⅲ Modified Electrode, Yan-Jie Zheng, Ai-Lin Liu, Yun Lei, Xin-Hua Lin

Journal of Electrochemistry

The poly SudanⅢ modified electrode was characterized by electrochemical impedance spectroscopy（EIS）and cyclic voltammetry (CV), while the electrochemical behavior of paeonol was studied by cyclic voltammetry (CV). The result shows that the poly Sudan Ⅲ modified electrode exhibits excellent electrocatalytic effect on the oxidation of paeonol. The peak currents of differential pulse voltammetry are linear to the paeonol concentrations over the range of 3.0*10^-7 ~ 2.2*10^-5 mol·L^-1. The detection limit has been estimated to be 5.0*10^-8 mol·L^-1. This method can be used for determination of paeonol content in real sample with satisfactory results.

Voltage Reversal Behavior In Microbial-Anode Fuel Cells, En-Ren Zhang, Jun-Le Niu, Lei Liu, Guo-Wang Diao

Journal of Electrochemistry

Voltage reversal behavior was investigated in microbial-anode fuel cells (MFCs). Electricity-producing biofilms were developed on the surface of anodes in MFCs inoculated with mixed inoculum from activated sludge. MFC duplicates generally exhibited different performances with respect to the internal resistance, the voltage output and the discharging duration when operating in batch mode. Voltage reversal was observed to occur first in the MFC with lower performance when connecting MFCs in series. Analysis of electrode potentials indicated that the potentials of microbial anodes quickly shifted to more positive values when enhancing discharge current, resulting in voltage reversal in MFCs. Increasing temperature would …

Electrocatalytic Oxidation Degradation Kinetics Of Oxalic Acid In A Cylindrical Electrochemical Reactor With Ti/Iro2-Ta2O5 Anode, Jing Su, Hai-Bo Lin, Hong Xu, Wei-Min Huang, Ya-Peng He

Journal of Electrochemistry

The electrocatalytic oxidation degradation kinetics of oxalic acid in a cylindrical electrochemical reactor with Ti/IrO₂-Ta₂O₅ as an anode was studied. The relation between instantaneous current efficiency and organic concentration in bulk was established based on the two paths for direct electrochemical oxidations, and the theoretical model was verified by experiments. The experimental resultswere reasonably consistent with the established kinetic model. Furthermore, the competition between the two paths was explored with the modelparameter analysis.

Graphene Quantum Dots Enhanced Electrochemical Performance Of Polypyrrole As Supercapacitor Electrode, Kun Wu, Si-Zhe Xu, Xue-Jiao Zhou, Hai-Xia Wu

Journal of Electrochemistry

With an objective to develop electrode materials with high specific capacitance and good stability, a completely new nanocomposite of Polypyrrole (PPY) and graphene quantum dots (GQD) was successfully obtained through in-situ polymerization of pyrrole in the presence of GQD suspension. The obtained composites with different mass ratios were characterized by X-Ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). GQD enhanced electrochemical performance of PPY and, as supercapacitor electrodes, the PPY/GQD composites with the mass ratio of PPY to GQD at 50:1 showed a competitive specific capacitance of 485 F·g^-1 at a scan rate of …