Engineering Commons^™

Calibration And Measurement Of Dielectric Properties Of Finite Thickness Composite Sheets With Open-Ended Coaxial Sensors, Stoyan I. Ganchev, Nasser N. Qaddoumi, Sasan Bakhtiari, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The application of open-ended coaxial sensors for dielectric measurement of finite thickness composite sheets is studied. Expressions for calculation of the complex aperture admittance for two geometries are presented. These expressions are used to calculate the dielectric constant of infinite half-space as well as finite thickness slabs. A more efficient method of such calculations, using a personal computer, for low to medium loss dielectrics is demonstrated. The question of when a dielectric layer may be considered as infinitely thick is also addressed, and examples are presented. A different calibration technique (compared to the conventional ones) is described and successfully implemented. …

An Interferometric Technique For B/A Measurement, E. Carr Everbach, R. E. Apfel

Engineering Faculty Works

An isentropic phase method is described for measuringin vitro the acoustic nonlinearity parameterB/A of several aqueous buffers, protein solutions, lipid oils, and emulsions. The technique relies upon the use of an acoustic interferometer to measure the small changes in sound speed that accompany a rapid hydrostaticpressure change of between one and two atmospheres. Average accuracies of 0.85% are attainable with this method.

Cumulative Average Pricing Method For Estimating Average Service Life, Mahendra Babu Hosangadi

Masters Theses

The study determined if accuracy of estimation of retirement price of industrial equipment was affected by using a cumulative average pricing (CAP) method at varying conditions of inflation rate, service life, and life characteristics. The study also determined the accuracy of estimating the average life of unaged data by simulated plant record (SPR) method. Thirty-six experiments were conducted at varying conditions of inflation rate, curve type and average life. The study was conducted for two left modal curves, two symmetrical modal curves and two right modal curves at 20 and 40 years average life using three different inflation rates: 3%, …

Transients In Power Systems, M. Belkhayat, J. Edwards, N. Hoonchareon, O. Marte, D. Stenberg, E. Walters

Department of Electrical and Computer Engineering Technical Reports

Power system engineering largely focuses on steady state analysis. The main areas of power system engineering are power flow studies and fault studies - both steady state technologies. But the world is largely transient, and power systems are always subject to time varying and short lived signals. This technical report concerns several important topics in transient analyses of power systems. The leading chapter deals with a new analytical tool-wavelets-for power system transients. Flicker and electric are furnace transients are discussed in Chapters I1 and IV. Chapter 111 deals with transients from shunt capacitor switching. The concluding chapters deal with transformer …

A Study On The Causes Of Variations In Transmissivity And Storativity During Pump Tests At Asylum Lake, Paul Joseph Pare

Masters Theses

Over a two year period, Western Michigan University ran a number of pump tests in the Asylum Lake Area in Kalamazoo, Michigan. The transmissivities and storativities calculated from these tests differed significantly from well to well in any particular test, and from pump test to pump test. Utilizing the computer programs AQTESOLV 3.0 and Aquifer Parameter Estimator, a number of T and S values were calculated. After analysis of the results, the following conclusion was drawn. The main reason for the deviations in the T and S values arose from the mixing of the results of numerous methods (some of …

Dynamic Pulse Buckling Of Columns With Viscous Damping, Murli Kadandale

Masters Theses

This is a study of dynamic pulse buckling of columns with viscous damping. The differential equations of motion were obtained using the Bemoulli-Navier hypothesis. The effects of axial and rotary inertia were included in the analysis. The Voigt-Kelvin model for a viscoelastic material is used. The Finite Difference Method was employed to solve the differential equations of motion. First columns without geometrical imperfections were studied, and a correlation between the damping modulus and the more familiar damping ratio was obtained. Then beams with initial geometrical imperfection were studied. A suitable dynamic buckling criterion was defined. It was observed that viscous …

Critical Assessment Of The Operator-Splitting Technique In Solving The Advection-Dispersion-Reaction Equation: 1. First-Order Reaction, Jagath J. Kaluarachchi, Jahangir Morshed

Civil and Environmental Engineering Faculty Publications

Operator-splitting technique (OST) is a common mathematical approach used in the solution of the advection-dispersion-reaction equation (ADRE), especially in the presence of biological decay, where the scales of transport and biological decay are far apart. The OST introduces a time-lag between the advection-dispersion and reaction stages by splitting the ADRE causing a breakdown of the physics of the problem, thus limiting its applicability. In this work, the applicability of the operator splitting technique is studied in parts. This first manuscript addresses the critical limitations of the operator-splitting technique as related to first-order decay, and the second manuscript extends the work …

Critical Assessment Of The Operator-Splitting Technique In Solving The Advection-Dispersion-Reaction Equation: 2. Monod Kinetics And Coupled Transport, Jahangir Morshed, Jagath J. Kaluarachchi

Civil and Environmental Engineering Faculty Publications

In the first manuscript of this two-part series, the behavior of the inherent time-lag error in the operator-splitting technique has been discussed. However, the discussion has been limited to the advection-dispersion-reaction equation with first-order kinetics. In this manuscript, the discussion is extended to address the applicability of the operator-splitting technique in solving the advection-dispersion-reaction equation with Monod kinetics. The discussion also considers the two-species coupled transport problem. The results of the analysis show that the behavior of the time-lag error causing a mass balance error is rather similar to those observed with first-order kinetics. The time-lag error directly depends on …

Compressible Flow Analysis Of Thrust Augmenting Ejectors, Mohamed Moujahid

Master's Theses - Daytona Beach

The present work was initiated due to the need for a method to understand and predict the thrust augmenting characteristics of jet ejectors. The mixing process in ejectors can be analyzed using either the control volume approach, or detailed models based on the Navier -Stokes Equations and the theory of turbulent jets. The control volume approach uses integrated forms of the conservation equations of mass, momentum and energy. It is chosen in the first part of the study since it affords the best vehicle for the parametric studies required to understand the potential of ejectors for a given application. Compressibility …

A Massively Parallel Computation Strategy For Fdtd: Time And Space Parallelism Applied To Electromagnetics Problems, Michael A. Jensen, Amir Fijany, Yahya Rahmat-Samii, Jacob Barhen

Faculty Publications

We present a novel strategy for incorporating massive parallelism into the solution of Maxwell's equations using finite-difference time-domain methods. In a departure from previous techniques wherein spatial parallelism is used, our approach exploits massive temporal parallelism by computing all of the time steps in parallel. Furthermore, in contrast to other methods which appear to concentrate on explicit schemes such as Yee's (1966) algorithm, our strategy uses the implicit Crank-Nicolson technique which provides superior numerical properties. We show that the use of temporal parallelism results in algorithms which offer a massive degree of coarse grain parallelism with minimum communication and synchronization …

Using Mathematica To Aid Simulation Analysis, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

As computer power has increased, so has the capability of software developers to write programs that assist people with time-consuming tasks. Mathematica is such a program. The objective of this paper is to demonstrate how Mathematica, a symbolic programming environment, can be used to aid simulation analysis. In addition to a general discussion of Mathematica’s uses, advantages, and disadvantages, several examples will be presented. The examples include using Mathematica for distribution fitting, queueing analysis, random number generation, and creating a surface plot for optimization.

The Effect Of Excitation Limits On Voltage Stability, Jyothi Ayyagari, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Voltage collapse has been commonly associated with insufficient reactive power support. Steady state studies have related reactive power generation limitations to the sudden onset of voltage instability. This paper extends this approach to the dynamic case. The relationship between the dynamic models and steady state behavior is established. The dynamic model is then used to investigate the sudden change in system stability when the maximum excitation limit is reached. Several illustrative examples are analyzed. Corrective actions are proposed which will move the physical system away from the region of instability.

Impacts Of The Extended-Weight Coal Haul Road System, Jerry G. Pigman, Joseph D. Crabtree, Kenneth R. Agent, R. Clark Graves, John A. Deacon

Kentucky Transportation Center Research Report

The Extended-Weight Coal Haul Road System, created by the Kentucky Legislature in 1986, consists of all roads which carry over 50,000 tons of coal in a calendar year. Trucks hauling coal on this system are authorized to exceed normal weight limits through the payment of an annual decal fee. A research study was initiated in July of 1992 to analyze the impacts of the extended-weight system.

Analyses in this report are based on the following: historical data on coal production and transportation: data from coal decal applications; interviews of legislators. transportation officials. coal company representatives. and coal trucking representatives: newspaper …

Guidelines For The Installation Of Left-Turn Phasing, Kenneth R. Agent, Nikiforos Stamatiadis, Bryan Dyer

Kentucky Transportation Center Research Report

The objective of this study was to update the guidelines to be considered when determining whether left-turn phasing should be used and the appropriate type at phasing to use. Emphasis was placed on high speed areas.

There were 264 intersections included in the study with data obtained tor 518 approaches at these intersections. The data included accidents and characteristics at the intersection. Traffic conflict data were collected. Simulation models were used to estimate delays.

Recommendations were made concerning guidelines to consider when deciding whether to install left turn phasing and whether to use protected-only or protected/permitted phasing. Variables considered included …

The Effects Of Risk Management Program Implementation On Worker Safety Knowledge, John C. Donnelly

Community & Environmental Health Theses & Dissertations

This study examined the effect of the implementation of a risk management program tool on worker safety knowledge in a composite building material fabrication facility whose workers suffered from an increasingly high injury (incidence) rate in recent years. Risk assessment codes (RACs) and job safety analyses (JSAs) were the primary tools used to introduce workers to the concept of risk. Because employee involvement is a crucial element in JSA development. employee input was frequently solicited throughout JSA development.

The study instrument consisted of a pre-test and post-test survey, to which an experimental and control group were subjected. The instrument was …

Design Modification And Optimization Of The Interior Ballistics For An Existing Naval Gun System., Gregory Allen Dennison

Electronic Theses and Dissertations

This thesis determines the physical, chemical and thermodynamic properties of an advanced solid propellant that can be used in the proposed upgrade of the Navy's 5-inch, Mark 45 gun system to achieve a muzzle energy of 14.928x16^6 ft-lbf (20.24 mega Joules(MJ)) firing a proposed 110 pound Precision Guided Munition (PGM). This energy level corresponds to an 95% increase over the current system that uses Navy Cool, or NACO, solid propellant and a 70 pound projectile. The propellant properties were parameterized using the interior ballistics simulation code known as Interior Ballistics of High Velocity Guns - 2 (IBHVG2), version 505D. The …

An Investigation Of Turbulent Taylor-Couette Flow Using Laser Doppler Velocimetry In A Refractive Index Matched Facility, Joseph C. Parker

Masters Theses

Turbulent Taylor-Couette flow between an annulus formed by two concentric cylinders with dead end walls is comprised of complex patterns of vortices. An experimental apparatus was designed to provide refractive index matching between the annulus and working fluid. Optical access was maintained through three sides of the annulus and one end wall. An aqueous solution of sodium iodide was formulated to match the refractive index of the Plexiglas annulus. Laser Doppler Velocimetry was used to measure the three components of velocity and turbulence intensity throughout a planar section in the annulus. The annulus dimensions were: ƞ= 0.672, d = 15.08 …

The Effect Of Rotor Wake/Exit Guide Vane Interaction On The Total Pressure Losses In An Airfoil Cascade, Aaron Mosebach

Masters Theses

Computational simulations have been performed to study the effects of unsteady rotor wakes on the total pressure losses and the boundary layer characteristics in a compressor cascade. In the numerical simulations, transitional and turbulent flow conditions were modeled at design and off-design inlet flow angles, and for varying rotor wake widths and wake velocity deficits.

First, simulations were performed in the absence of rotor wakes at the inlet of the EGV (Exit Guide Vane) cascade. Second, simulations were performed for different wake width and wake velocity deficit values at the inlet of the EGV cascade. The majority of the numerical …

Activation Of Precipitated Iron Fischer-Tropsch Catalysts, Mehul D. Shroff

Chemical and Biological Engineering ETDs

The Fischer-Tropsch Synthesis (FTS) is an important step in the manufacture of synthetic fuels from coal. The use of iron catalysts for FTS, though desirable from the standpoint of process economy, is hampered by problems relating to catalyst attrition and carbon buildup. In addition, from a research perspective, there has been a long-standing controversy in the literature with regard to the nature of the active phase.

The effect of activation and reaction treatments on the resulting phase transformations in a commercial, precipitated and spray-dried, Fe₂O₃ - CuO - K₂O Fischer-Tropsch catalyst have been studied. Different …

A Finite Element Analysis Of The Forward Rod Extrusion Process With An Emphasis On Die Profile Optimization, Mahmoud Mohamed Nagui Shatla

Archived Theses and Dissertations

No abstract provided.

Simultaneous Detection System Combining Studies Of Programmedpotential Step Technique And Time-Resolved Ftir Spectroscopy, Shigang Sun, Xiaoyu Chen, Guoqiang Lu, Wenfeng Lin, Nanhai Li, Shenpei Chen, Hongping Dai, Jiqian Mu

Journal of Electrochemistry

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A Photoelectrochemical Investigation Of A.C.Modulated Passive Films On 304 Stainless Steel In Weak-Alkaline And Neutral Solution, Tianbao Du, Chunan Cao, Jiakang Yu, Haichao Lin

Journal of Electrochemistry

A photoelectrochemical investigation has been carried out on AISI 304 stainless steeI AV modulated passive film in 0.1mol/L Na₂B₄O₇ and 0.5 mol/L Na₂SO₄ solution. Photo current curve depends on the potential, passive condition and testing solutions. The results of the measurements indicate that the photoresponse is determined by the defects in the electronic structure of the films whenthe defects lead to localized states in the bandgap region. It is concluded that the passive film on AISI 304 stainless steel is in a highly disordered amorphous state.

Growth Kinetics And Breakdown Of Passive Films On Rebar Electrodes In Simulated Cement Pore Solution, Wei Chu, Yuanxiang Shi, Baoming Wei, Yong Yang, Xuguang Chen, Zugeng Lin

Journal of Electrochemistry

The growth kinetics and breakdown of passive films on REBAR electrodes insimulated cement solution (pH=12.5 and 13.8) have been investigated using in situ photoelectrochemical methods and potential step method. The results show that there are two mainstages in the growth of the film, with two rate functions characterized by linear relation between thefilm thickness and the direct logarithm of time. There is a sign in laser-scanning photoelectrochemical microscopic image just before the passive film breaks down. The addition of inhibitor NaNO₂ changes the growth kinetics and thickness of the film, and therefore improves the resistance of pitting corrosion induced …

Fabrication And Electrochemical Behaviors Of Thin Films Of Polyaniline By Langmuir-Blodgett Technique And Electropolymerization, Benzeng Hua, Zhaoxiong Xie, Yanzhen Chen, Yunhong Zhang

Journal of Electrochemistry

Hydrogen-bond between stearic acid and aniline in subphase lead to Langmuir monotayers of stearic acid-aniline, the molecular area of stearic acid-aniline is 26 nm². With surfacepressure increased into 50 mN/M, the hydrogen-bond would be rearranged, aniline molecular transales into vertical from horizontal, surface pressure decreased quickly. A new kind of Langmuirmonolayer is formed instead of collapse, it's molecular area decreases into 24 nm² and thicknessin creases with 0.25 nm. After electroreduction of L-B films depeited onto the surface of SnO₂ electrode, anilne layers between two stear acid matix could be polymerized into thin films of polyanilne. …

Cyclic Voltammetric Calorimetry Studying The Deposition Of Copper Of Pt Electrodes, Yongchun Zhu, Robin. H. J. Clark

Journal of Electrochemistry

In the present paper, cyclic voltammetric calorimetry has been used to study thedeposition of copper on platinum electrode from LiClO₄ aqueous solution. Cyclic voltammetric thermogram and cyclic voltammetric differential thermogram show that the deposition of copper on theelectrode is an exothermal process with a strong interaction between copper and platinum layer (-3227.0 kJ /mol). The electrochemical oxidation of the deposited copper is composed of twoprocesses: an endothermal activation process with 747.0 kJ/mol of activation enthalpy, and an exothermal oxidation reaction with -189.9 kJ/mol of the reaction enthalpy, which are accord with the data from the theoritical estimation and thermodynamic …

Electrochemical Behaviors Of The Loaded Stainless Steel In Dilute Thiosulphate Solution, Changjian Lin, Zude Feng, Fuling Lin, Fayang Wang, Jianguang Tang, Yuanhui Wang

Journal of Electrochemistry

The electrochemical behavior of 18/8 stainless steel in dilute thiosulphate solutionduring strained loading was studied by various electrochemical techniques and scanning electronmicroscope. It is evidenced that the corrosion activity of stainless steel increased with strained loading. The dynamic process of repassivation, which may datermine the initiation, the cease and development of the stress corrosion cracking for stainless steel, was strongly influenced by both electrochemical andloading conditions. Pitting corrosion may locate preferentially on the sites which was suffered mostloading. The propagation of pitting corrosion of stainless steel may induce stress corrosion crakingunder certain conditions.

Study Of The Modified Electrolytic Manganese Dioxide, Guohui Yuan, Dewei Chu, Rihui Shen, Hongwei Pan, Cuifen Zhang

Journal of Electrochemistry

A modified electrolytic manganese dioside doped with Bi (Bi-EMD)wasprepared and examined by XRD and XPS. It is predominantly γ-mnO₂ and the Bi exists as Bi₂O₃ in the modified material. The content of Bi in Bi-EMDs increased with the increasement of Bi³⁺ concentration in electrolyte, and reached 14.3(wt)% from the bath of 0.008 mol·L^-1 Bi³⁺ used. Some Zn/Bi-EMD prototype batteries of AA size were assembled, and which cycle life tests showedthat the Bi-EMD has better reversibility.

The Composition Structure And Corrosion Resistance Of Al-Mn Alloy Plating, Jiaju Guo, Naiming Guo

Journal of Electrochemistry

The Al-Mn alloy plating was electrodeposition from low temperature molten salts (below 200℃), its chemical composition control, corrosion resistance as well as the relationshipbetween chemical composition and structure were studied. The results indicate that the main effect onchemical composition of Al-Mn alloy plating is Mn ion concentration in molten salts. The Mn contentin the range of 25～40(wt)%, Al-Mn alloy plating has amorphous structure. In 0.5 mol/L H₂SO₄ and NaCl solution ,corrosion resistance of the alloy plating is much better. When the alloy has amorphous structure, corrosion resistance of plating has been remarkably increased.

Studies Of In-Situ Raman Spectroscopy On Deprotonation And Degeneration Of Ppy Films, Jinsong Gao, Jing Chen, Yanzhen Chen, Qi Xue, Zhongqun Tian

Journal of Electrochemistry

By combining the in-situ Raman spectroscopic technique with the normal electrochemical measurements, the behavior and structure of PPY films in neutral or basic solutions were studied. The oxidized PPY loses protons on the N atoms of pyrrole rings and is deprotonated in these solutions, resulting the formation of the quinoid structure. It makes the C=C stretching vibration bonds of PPY split. Because this quinoid structure can′t be further oxidized, the PPY becomes more difficult to be oxidized and less reversible with the increasing of pH value of solutions and the degree of deprotonation of PPY. In the strong basic solution …

Catalytic Oxidation Of Methanol On Pt/C-Spe And Ptru/C-Spe Electodes, Aihua Su, Changzhi Li, Gongquan Sun, Ying Zhang, Tianhong Lu

Journal of Electrochemistry

Anode catalysts of methanol oxidation for direct methanol fuel cell, Pt/C and PtRu/C, ere prepared by chemical reduction in this work. The results indicated that the PtRu/C showed higher electrocatalytic activity than that of Pt/C. It was explained by XRD and XPS analyses that the existence of Ru enhanced the catalytic activity for electrochemical oxidation of methanol.