Engineering Commons^™

Calculation Of Corrosion Rate Of Passive Metals With Charge Curve Analysis Technique, Yuan-Sheng Zhang, Min Gong

Journal of Electrochemistry

This work contains two parts: (1) A charge curve equation having no appro-ximation for passivated metal corrosion systems is derived and compared with the routine charge curve equation, which is virtual only when the polarization is minim(linear range). (2) It is simpler to analyze charge curve data by from of charge differential equation than from charge curve equation. After the charge curve data are measured, the slope of charge curve is computed by numerical differentiation method, then the charge differential equation may be transformed to a set of linear equations using polynomial approximation. The electrochemical parameters of corrosion system would …

Direct Electrolysis Of Seawater On Conducting Film For Microbial Anticorrosion 1. Simulation And Measurement Technique, Wei-Ling Hu, Ling-Ling Wu, Jing Zhou, Jing-Xin Li, Jin Luo, Zhong-Hua Lin

Journal of Electrochemistry

Based on the electrochemical micro probe and the weak signal detection technique, simulated test and measurement system were set up by the use of four-electrode cell(including a micro electrode), bipotentiostat, lock-in amplifier and three-dimensional micro manipulating device. Based on the system, the micrometer scale concentration distribution of trace hypochlorite, which is produced by direct electrolysis of seawater on the conducting film for preventing microbial corrosion has been obtained for the first time. Both relationships between concentration of hypochlorite and its reduction current, which is termed an working curve, and between the reduction current of hypochlorite and measured time are reported.

The Techniques Of The Paired Electrosynthesis, Hong-Kun Zhang, Deng-Ping Gu

Journal of Electrochemistry

In this Paper, we introduce our work on paired electrosynthesis. In conjunction with our research practice, we introduce electrolytic conditions,such as material of electrode ,courrent density and electrolytic temperature etc,as reference for researcher. We categorize the paired electrosynthesis techniques to widen our view on the paired electroorganic synthesis and to promote the deveopments of paired electrosynthesis techniques.

A Study Self-Passivation Of Passivie Film Of Stainless Steel In Vinylon Aldehyde Solution, Si-Fu Hu, Chuan-Bi Xu, Zhu-Qiu Cheng

Journal of Electrochemistry

Properties of self-passivation for the anodic passive film of 1Cr18Ni9Ti and the firsthand passive film of SUS 36 stainless steel in vinylon aldehyde solution(H₂SO₄(240 g/L)+Na₂SO₄(70 g/L)+HCHO(25 g/L)+[Fe³⁺](35.4 mg/L)+[Cl^-](240 mg/L) at 70 ℃ were studied by galvanostatic and potentiostatic polarization mesurements. The effects of compponents of vinylon aldehyde solution, i.e. Fe³⁺ and Cl^-, on the passivation behaviours of stainless steel have also been investigated. The experimental results showed there is a conversion zone of the active/passive state if the area ratio of active/passive state on these …

Influence Of Thiourea And Its Derivate On The Process Of Cathodic Electrodeposition Of Copper, Yun-Hui Dong, Ai-Hong Zou, Yun-Xia Zhao

Journal of Electrochemistry

The effects of thiourea and its derivate on the electrodeposition of copper from the dilute acid sulphate solutions have been studied by using potential sweep techniques at quasisteady state. Limiting current densities (I_d), exchange current densities (i₀) and α_n are obtained by data processing with the least square method. Thiourea has a depolarizing effect on the copper depositing at concentrations below 8 mg·L^-1, and a polarizing effect at higher concentration (>10 mg·L^-1), and it changes the mechanism of copper deposition reaction. Propenyltiourea and Phenylthiourea have a depolarizing effect on the …

Preparation And Ionic Conductivity Of Nanometer-Sized Li2+XGdXSi1+XO3 By The Sol-Gel Method, Ru-Fen Chen, Xiu-Qin Song, Hua-Ting Liu

Journal of Electrochemistry

Li_2+xGd_xSi_1-xO₃(x =0～0.15) samples have been prepared by the Sol-Gel method. The power samples were characterized by DTA-TG, XRD and TEM. Ionic conductivity of the sinter was determined by means of A-C impedance measurements. The experimental results showed that the range of solid-solution was 0 < x ≤ 0.09, while the conductivity of samples raised with increasing amount of Gd₂O₃ added, and average grain size of samples was 80 nm. In comparing with the samples by the conventional solid state reaction, the samples prepared by Sol-Gel method required lower temperature and presented higher ionic conductivity.

A Study Of The Corrosion On Bronze, Hong-Fan Zhu, Hao Zhou

Journal of Electrochemistry

The bronze is the treasure in chinese metallic antique, which was typified by product in Shang-Zhou period (three thousands years ago). Because of corrosion, archaeological messages, such as inscription and pattern on the surface of bronze, would be damaged then the value of bronze antique decreased. The bronze disease is a common disease which forms powdery rust on the surface of bronze in atmospheric environment, the powdery rust emerge from under incrusted rust, then spreads, and eventually leads to bronze damaged. This paper investigates the bronze disease. According to the chemical and electrochemical tests in simulated occluded cell, the variation …

The Effects Of Metallic Cobalt Abbition On The Performance Of Pasted Nickel Electrodes, An-Bao Yuan, Jian-Qing Zhang, Wan-Chun Ding, Shao-An Cheng, Chu-Nan Cao

Journal of Electrochemistry

The Ni-foam pasted nickel electrodes prepared by coprecipitated Ni_1-XZn_X(OH)₂ with and without cobalt power addition have been studied. The electrode with addition of metallic cobalt showed a higher performance both in discharge capacity and cycle life. It is known from the experiment results that the addition of Co can remarkably increase the active material utilization which is suggested to be improvement of discharge depth due to the conducting CoOOH formed in the first activation charging. The superior capacity during cycling could be attributed to the synergistic action of zinc and cobalt addition ,especially to the …

Study On Synthesizing Of 2-Methylbutanoic Acid By Indirect Electrooxidation, Chong-Tao Zhao, Ze-Shan Zhu

Journal of Electrochemistry

The working conditions of synthesizing 2-methylbutanoic acid by oxidizing 2-methyl-1-butanol with tetrabutylammonium hydrosulfate (TBAS) or tetrabutylammonium perchlorate (TBAP) as phase transfer catalyst in sulfuric acid Cr(Ⅵ) oxidation medium was studied. The Cr(Ⅵ) oxidation medium could be electrolytic regenerated from Cr(Ⅲ), during above oxidation reaction. Under the optinum condition, the yield of 2-methylbutanoic acid is more than 95%.

The Ac-Impedance Analysis For Pluse Oxide Film Of Aluminium Alloy, Ai-Ling Du, Xi-Cheng Ma, He-Ming Zhang

Journal of Electrochemistry

Bode diagrams for aluminum PC (abbreviated from pulse current) oxide films were first obtained by AC-impedance measurements in a wide range of frequency. The experimental results show that different kinds of electrical equivalent circuits can be used for representing PC films and DC (abbreviated from direct current) oxide films separately, the main differences between them are their porous layers, the PC films are more even with little defects.Those are also verified by SEM and V-I characteristic curve measurements.

Electrochemical Synthesis Of Fes Electrode And Its Behavior Measurement, Cong-Sheng Guan

Journal of Electrochemistry

The Potential for the electrochemical synthesis of FeS electrode has been obtained by cyclic voltammetry. FeS electrodes were synthesiaed by controlling Fe electrode at -1.0 V in LiCl-KCl-Li₂S and Li(FClI)-Li₂S melts and their behavior were measured also. The FeS electrode synthesized in molten Li(FClI)-Li₂S has the best charge and discharge properties.

When Bad Leads To Good: Airplane Crashes And The Political Psychology Of Stress, Ibpp Editor

International Bulletin of Political Psychology

This article begins a series on research presented at the 1999 Annual Convention of the American Psychological Association. The article suggests some of the complexities in the construct of stress and applies them to research on the psychological aftermath of surviving an airplane crash.

An Assessment Of Renewable Energy Options At Brooks Camp, Katmai National Park And Preserve, Florida Solar Energy Center, Gerard Ventre

FSEC Energy Research Center®

At the request of Brad Richie, NPS Alaska Support Office and manager of the Brooks Camp relocation project, a renewable energy team (RET) from the Department of Energy/Federal Energy Management Program (DOE/FEMP) conducted an on-site power system assessment at Brooks Camp. The assessment included:

• An evaluation of the current electrical loads at the site,
• An evaluation of the current facility power system,
• A review of the plans for the relocated facility and planned power needs,
• An assessment of the renewable resources and possible siting options, and
• The identification of potential opportunities for renewable power systems.

The RET activities were coordinated …

University Nanosatellite Distributed Satellite Capabilities To Support Techsat 21, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A published article that included Professor Bob Twiggs titled "University Nanosatellite Distributed Satellite Capabilities to Support TechSat 21" from August 23, 1999.

Nutrient Balance On Nebraska Livestock Confinement Systems, Richard K. Koelsch, Gary Lesoing

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Managing the environmental risk associated with livestock production is a significant challenge. Nitrogen and phosphorus are commonly implicated as the sources of ground and surface water quality problems associated with livestock production. The degree of imbalance between these nutrient inputs and the managed nutrient outputs for a livestock operation defines the magnitude of potential environmental risk and provides insight as to the underlying causes of these challenges. A nitrogen and phosphorus balance was constructed for 33 Nebraska confinement livestock operations. Twenty-five and 17 of these operations experienced significant nitrogen and phosphorus imbalances, respectively (50% more nutrient inputs than outputs). Nutrient …

Apparatus And Method For Triboelectrostatic Separation, John M. Stencel, John L. Schaefer, Heng Ban, James K. Neathery

Center for Applied Energy Research Faculty Patents

A triboelectrostatic separation apparatus includes a separator with an inlet, a separation chamber, first and second electrodes, a variable voltage source for applying respective positive and negative voltage potentials to the electrodes, a pair of separated particle outlets and a curtain gas flow generation system. The curtain gas flow generation system includes a source of curtain gas at positive pressure, a metering valve for matching curtain gas flow velocity to particle flow velocity and flow straighteners for eliminating eddy currents. A method for separating electrostatically charged particles is also described.

Isotropic Dielectric Functions Of Highly Disordered AlXGa1-XInp (0≤X≤1) Lattice Matched To Gaas, Mathias Schubert, John A. Woollam, G. Leibiger, B. Rheinlander, I. Pietzonka, T. Sab, V. Gottschalch

Department of Electrical and Computer Engineering: Faculty Publications

Determination of the complex dielectric function and the critical-point energies of (Al_xGa_1-x)_0.51In_0.49P, over the full range of composition x and for photon energies E from 0.75 to 5 eV is reported from variable angle of incidence spectroscopic ellipsometry. Native-oxide effects on the (Al_xGa_1-x)_0.51In_0.49P optical functions are removed numerically. The highly disordered state of the metalorganic vapor-phase epitaxy grown samples is analyzed by transmission electron microscopy. Optical anisotropy investigations revealed that the order-induced optical birefringence is negligible throughout. The augmentation of A. D. …

An Experimental And Analytical Study Of Ice Part Fabrication With Rapid Freeze Prototyping, Wei Zhang, Ming-Chuan Leu, Guanghua Sui, Zhiming Ji

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid Freeze Prototyping (RFP) is a new solid freeform fabrication process that builds an ice part by rapidly freezing water layer by layer. In this paper, we will present our recent progress in the development of this novel process. An experimental system has been built for conducting the research. It consists of an XY-table and Z-stroke driven by micro-stepping motors and a water dispensing and deposition subsystem which incorporates a solenoid valve and a syringe pump placed inside a freezer. Simple heat transfer analysis is made to help select proper values of process parameters and predict part building failures. Example …

Assessment Of Environmental Performance Of Rapid Prototyping And Rapid Tooling Processes, Yanchun Luo, Ming-Chuan Leu, Zhiming Ji

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A method for assessing the environmental performance of solid freeform fabrication (SFF) based rapid prototyping and rapid tooling processes is presented in this paper. In this method of assessment, each process is divided into a number of life stages. The environmental effect of each process stage is analyzed and evaluated based on an environmental index utilizing the Eco-indicators that were compiled by PreConsultants of the Netherlands. The effects of various life stages are then combined to obtain the environmental performance of a process. In the assessment of SFF processes, we consider the material use in the fabrication of a part, …

Rapid Tooling By Integrating Electroforming And Solid Freeform Fabrication Techniques, Bo Yang, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper describes a rapid tooling process that integrates solid freeform fabrication (SFF) with electroforming to produce metal tools including molds, dies, and electrical discharge machining (EDM) electrodes. Based on experimental data analysis, the geometry and material of the SFF part, the properties of the electroformed metal, and the process parameters are significant factors that cause inaccuracy in the manufactured tools. Thermomechanical modeling and numerical simulation is used to determine the geometry of the SFF part and the electroform thickness for minimizing the manufacturing time and cost while satisfying the tooling accuracy requirement.

Network Modeling Of The Convective Flow And Diffusion Of Molecules Adsorbing In Monoliths And In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A cubic lattice network of interconnected pores was constructed to represent the porous structure existing in a monolith (continuous bed) or in a column packed with porous chromatographic particles. Expressions were also constructed and utilized to simulate, through the use of the pore network model, the intraparticle interstitial velocity and pore diffusivity of adsorbate molecules in porous chromatographic particles or in monoliths under retained and unretained conditions. The combined effects of steric hindrance at the entrance to the pores and frictional resistance within the pores, as well as the effects of pore size, pore connectivity, n(T), of the porous network, …

Polycrystalline Conducting Polymers And Precursors Thereof Having Adjustable Morphology And Physical Properties, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

Polycrystalline materials containing crystallies of precursors to electrically conductive polymers and electrically conductive polymers are described which have an adjustable high degree of crystallinity. The intersticial regions between the crystallites contains amorphous material containing precursors to electrically conductive polymers and/or electrically conductive polymers. The degree of crystallinity is achieved by preparing the materials under conditions which provide a high degree of mobility to the polymer molecules permitting them to associate with one another to form a crystalline state. This is preferable achieved by including additives, such as plasticizers and diluents, to the solution from which the polycrystalline material is formed. …

Electrodeposition Of Cerium-Based Coatings For Corrosion Protection Of Aluminum Alloys, James O. Stoffer, Thomas J. O'Keefe, Xuan Lin, Eric L. Morris, Pu Yu, Srinivas Pravin Sitaram

Chemistry Faculty Research & Creative Works

A process for enhancing the corrosion resistance of an aluminum-containing component with a cerium based coating. An aluminum-containing cathode and an oxygen- evolving anode are immersed in an electrolyte comprising water, solvent, oxidizing agent and cerium ions. An electrical current is passed through the electrolyte by applying electrical current to deposit a cerium based coating onto the cathode. An electrolyte for use in depositing a cerium based coating. An electrodeposited cerium-based coating. An aluminum aircraft structural component having a cerium-based coating thereon.

Models For Magnetoresistance In Tunnel Junctions, Shi C. Zhang, P. M. Levy

Materials Science and Engineering Faculty Research & Creative Works

We show there are putative pitfalls when one predicts the magnetoresistance of magnetic tunnel junctions (JMR) based on different toy models. Amongst them are the sensitivity of the MR to the details of the profile of the potential barrier between the metallic electrodes and the insulating barrier, and the common assumption of only one band of electrons. We indicate the ingredients that are necessary to obtain a more complete description of the JMR of magnetic tunnel junctions.

Ccfss Technical Bulletin August 1999, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Technical Bulletins (1993 - 2020)

No abstract provided.

Acuta Enews August 1999, Vol. 28, No. 8

ACUTA Newsletters

In This Issue

Annual Conference Highlights

ACUTA EVENTS

ACUTA Upgrades Web Site

DC Update

Indiana University Hosts Local Events

Board Report

Overheard on the Listserve

Welcome New Members

Positions Available

Ccfss News August 1999, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

Chu Spaces - A New Approach To Describing Uncertainty In Systems, Vladik Kreinovich, Guoqing Liu, Hung T. Nguyen

Departmental Technical Reports (CS)

This paper proposes the use of a specific type of categories for modeling and fusing information in complex systems in which uncertainty of various types need to be taken into account.

Neural Network Approach To Speech Pathology, Antonio P. Salvatore, Nicole A. Thorne, Charlotte M. Gross

Departmental Technical Reports (CS)

A speech problem can be caused by different reasons, from psychological to organic. The existing diagnostic of speech pathologies relies on skilled doctors who can often diagnose by simply listening to the patient. We show that neural networks can simulate this ability and thus provide an automated (preliminary) diagnosis.

Kolmogorov Complexity-Based Ideas For Locating Text In Web Images, Martin Schmidt, Vladik Kreinovich, Luc Longpre

Departmental Technical Reports (CS)

The gaining popularity of the World Wide Web increases security risks. Search tools monitor plain text in web pages, but search for text in graphical images is still difficult. For this search, we use the fact that the compressed images with text have different size than images without text.