Engineering Commons^™

Solitary Waves And Supersonic Reaction Front In Metastable Solids, Hendrik J. Viljoen, Lee L. Lauderback, D. Sornette

Hendrik J. Viljoen Publications

Motivated by an increasing number of remarkable experimental observations on the role of pressure and shear stress in solid reactions, explosions and detonations, we present a simple toy model that embodies nonlinear elasticity and dispersion as well as chemical or phase transformation. This generalization of the Toda Lattice provides an effective model for the description of the organization during an abrupt transformation in a solid. One of the challenges is to capture both the equilibrium degrees of freedom as well as to quantify the possible role of out-of-equilibrium perturbations. In the Toda Lattice, we verify that the particle velocities converge …

Design Methods For Auger Cip Piles In Compression, Giuliana A. Zelada, Richard Wesley Stephenson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This Paper Reports on a Study of 43 Compression Load Tests (Five Fully Instrumented) and Ten Pullout Tests of Auger Cast-In-Place (ACIP) Piles in Sand. Eight Design Methods Reported in the Literature Were Used to Predict the Measured Pile Capacities. Ultimate Load Capacities of the ACEP Load Tests Were Determined using Two Different Definitions of Ultimate Capacity and Compared with Predictions. Load Transfer Behavior Was Determined from a Study of the Fully Instrumented Pile Tests and Compared to Predicted Values. Recommendations Are Made Regarding the Design Approach Most Appropriate for These Foundations and the Best Procedure for Estimating Ultimate Capacity …

Prediction Of Airfoil Stall In Icing Conditions Using Wing Surface Pressures, Erik Pederson

Masters Theses

This thesis presents work on a Normalized Lift Coefficient instrumentation system that predicts airfoil stall in icing conditions. The system uses four surface pressures, measured aft of the ice formation, from which the aircraft's normalized lift coefficient is determined. The pressure port locations were selected such that the calibration algorithm remains nearly constant as the leading edge ice shape and thickness change. Data collected in the Western Michigan University Wind Tunnel is presented for three ice formations varying in both shape and thickness. The ice and no ice conditions were compared and a set of four ports was found that …

Texture And Young’S Modulus Of Nickel/Gamma-Alumina Composites, Abdulaziz Alamr

Masters Theses

To improve Young's modulus of 2024-T3 rolled aluminum specimens, it was electroplated with nickel reinforced with nano-particles of γAl₂O₃. Taguchi method was used to investigate the effect of coating variables, which were current density, coating time, and mixing rate, on the coating thickness. The coatings were tested for crystallographic texture, using pole figures of (200) and (111) for nickel and (400) for γAl₂O₃. Surface topography was measured using WYKO Vertical Interference Microscope. The crystallographic texture of nickel in the coating depended on the coating conditions. A universal testing machine was- used to …

Residual Stress And Wear Resistance Of Composite Coatings Of Nickel/Gamma-Alumina, Khaled Abdulrahman Al-Ogab

Masters Theses

Nickel reinforced with nanoparticles of γ−Al₂O₃ have been successfully codeposited on 2024-T3 cold rolled aluminum alloy by electrodeposition with direct current. The effects of current density, particle concentration in the nickel sulfamate bath, air agitation, and coating time on Ni/γ−Al₂O₃ composite have been investigated. The residual stresses and wear resistance of the Ni/γ−Al₂O₃ composite have been measured using X-ray diffractometer and pin-on-disk techniques respectively. The residual stress and wear resistance behavior of the composite were compared with those of nickel-only deposits. An annealed ground nickel, which was mechanically removed from the …

Small Below-Endurance-Limit Cycle Damage Contributions In Variable Sequence Loading For 2024-T351 Aluminum Alloy, Christopher M. Ngiau

Masters Theses

It is a common practice in industry today to totally discard the presence of small below-endurance/fatigue limit cycles while calculating damage accumulation using the Palmgren-Miner rule. However, it was experimentally found in a number of studies that small cycles with stress amplitudes below the fatigue/endurance limit do in fact contribute significantly to the damage accumulation in all types of materials. There was a need to investigate cases where small cycles would only be present for a certain percentage of the material's life. An experimental study was done on 2024- T351 aluminum alloy. Loading was done in low and high cyclic …

Time-Varying System Identification Using Modulating Functions And Spline Models With Application To Bio-Processes, Sridhar Ungarala, Tomas B. Co

Chemical & Biomedical Engineering Faculty Publications

Time dependent parameters are frequently encountered in many real processes which need to be monitored for process modeling, control and supervision purposes. Modulating functions methods are especially suitable for this task because they use the original continuous-time differential equations and avoid differentiation of noisy signals. Among the many versions of the method available, Pearson–Lee method offers a computationally efficient alternative. In this paper, Pearson–Lee method is generalized for non-stationary continuous-time systems and the on-line version is developed. The time dependent parameters are modeled as polynomial splines inside a moving data window and recursion formulae using shifting properties of …

Finite-Aperture Wire Grid Polarizers, Michael A. Jensen, Gregory P. Nordin

Faculty Publications

The transmission characteristics of wire grid polarizers fabricated in finite apertures are investigated by using a three-dimensional finite-difference time-domain formulation. Specifically, the optical transmissivity and extinction ratio are characterized for a wide variety of geometrical parameters including aperture size in both dimensions, conducting wire fill factor, and polarizer thickness. A dispersive material model is used to investigate the performance of polarizers fabricated by using realistic metals at infrared wavelengths. The results indicate that the aperture dimension significantly impacts the polarizer transmission behavior and that the extinction of the unwanted polarization is often limited by depolarizing scattering that is due to …

The Viscoelastic Behavior Of Pigmented Latex Coating Films, Katharina Prall

Electronic Theses and Dissertations

The mechanical properties of paper coatings are essential for use performance of coated paper (e.g. calendering, printing degradation during printing operations, pick). This study investigates the microscopic and macroscopic mechanisms that determine the viscoelastic behavior of pigmented latex coating films. Pigmented coating layers were prepared with different microstructures. This was achieved by using different pigment types and shapes (polystyrene plastic pigment - spheres, precipitated calcium carbonate - rhombs, clay - plates), and changing pigment volume concentration (PVC). Two styrene-butadiene latices with different degree of carboxylation (acidic level 0.3% and 4.5%) were evaluated to determine effect of adhesion. The viscoelastic material …

Itanium's New Basic Operation Of Fused Multiply-Add: Theoretical Explanation And Theoretical Challenge, Vladik Kreinovich

Departmental Technical Reports (CS)

A new Intel's 64-bit chip Itanium has a new instruction set which includes a fused multiply-add instruction x1+x2*x3. In this short article, we explain the empirical reasons behind the choice of this instruction, give possible theoretical explanation for this choice, and mention a related theoretical challenge.

Novel Processing Of Hydroxyapatite-Zirconia Composites Using Nano-Sized Particles, Mark R. Towler, I. R. Gibson, S. M. Best

Chemical and Biochemical Engineering Faculty Research & Creative Works

A method to produce composites of hydroxyapatite (HA) with ZrO2 (Y-TZP) additions between 0 and 10 wt % at a low sinter temperature of 750 °C is presented. The method limits the amount of reaction between the HA and ZrO2. A ZrO2 loading level that would improve strength while limiting the decomposition of the HA is studied.

Computer-Based Methods For Constructing Two-Level Fractional-Factorial Experimental Designs With A Requirement Set, Steven L. Forsythe

Theses and Dissertations

This dissertation developed four methodologies for computer-aided experimental design of two-level fractional factorial designs with requirement sets (DOE/RS). The requirement sets identify all the experimental factors and the appropriate interaction terms to be evaluated in the experiment. Taguchi graphs and similar manual methods provide techniques for solving the DOE/RS problem. Unfortunately, these methods are limited because they become difficult to use as the number of factors or interaction terms exceeds ten. This research showed that the DOE/RS problem belongs to a class of difficult-to-solve problems known as NP-Complete. It is the combinatorial nature of NP-Complete problems that causes them to …

Estimating Budget Relationships With A Leontief Input-Output Model, Guenever L. R. Shariff

Theses and Dissertations

Forty years ago, the Office of the Secretary of Defense proposed using the Leontief input-output model to assess tradeoffs in the Department of Defense's (DoD) budget. We demonstrate that the Leontief input-output model can assess tradeoffs in the Air Force's budget. To increase one part of the Air Force's budget, we need to know the interrelationships between that budget area and the other areas. In this research, we look at different methods of how the functional areas might interact. We demonstrate our methodology on two data sets - DoD and the Air Force aggregate budget data. By looking at how …

An Atm System Model And Wireless Channel Simulation, Karen Dunne

Masters

Congestion in the low frequency regions of the electromagnetic spectrum and demand for support of high bandwidth applications has prompted widespread investigations into networking technologies and communications media. Traditional networking technologies such as Ethernet that are not capable of adequately supporting high bandwidth applications (e.g. videoconferencing) are being replaced by high speed, high bandwidth technologies such as Asynchronous Transfer Mode (ATM). In the communications media market, wireless systems are becoming ubiquitous due to their ease of installation and maintenance costs. In this research, the networking technology of interest is ATM. ATM used a cell switching architecture that allows seamless support …

Covalidation Of Dissimilarly Structured Models, Samuel A. Wright

Theses and Dissertations

A methodology is presented which allows comparison between models constructed under different modeling paradigms. Consider the following situation: Two models are constructed to study different aspects of the same system. One model simulates a fleet of aircraft moving a given combination of cargo and passengers from an onload point to an offload point. A second model is a linear programming model that optimizes the aircraft and route selection required for the same scenario. We develop a methodology to structure the comparison between large-scale models such as these. Models that compare favorably using this methodology are deemed covalid. Models that perform …

Optimal Design Of Beams Undergoing Harmonic Bending And Torsion Using Finite Elements, Arnoldo Garcia

Theses and Dissertations - UTB/UTPA

In this study, the objective is to determine the natural frequency of an Euler-Bernoulli beam with an intermediate mass and inertial component. The beam is studied with fixed and relaxed end conditions. The beam is also modeled with an intermediate support. The models are then compared with an approximate closed form solution for the natural frequency. Results show that the closed form equation is within 2% percent when compared to the exact natural frequency equation.

The beam is modeled with a finite element software. The goal is to minimize the weight of a beam structure subject to harmonic excitation. Results …

Direct Generation Of Optical Diffractive Elements In Perfluorocyclobutane (Pfcb) Polymers By Soft Lithography, Gregory P. Nordin, J. Ballato, P. C. Deguzman, S. Foulger, H. Shah, D. Smith

Faculty Publications

Optically diffractive line gratings with 0.58- m feature sizes have been generated in 100- m perfluorocyclobutane (PFCB) polymer films by direct micromolding using only a silicon master. Strong reflectivities from the green to red portions of the visible spectrum, depending on incident beam angle, were observed with 3 dB bandwidths of approximately 30 nm. This negative mold-free technique permits, for the first time to our knowledge, feature reproduction at submicrometer size scales, eliminates several steps from conventional soft lithographic methods, and marks itself as a practical means for rapidly generating planar photonic structures that operate spectrally in the visible and …

Effect Of Gate Leakage Current On Noise Properties Of Algan/Gan Field Effect Transistors, S. L. Rumyantsev, N. Pala, M. S. Shur, R. Gaska, M. E. Levinshtein, M. Asif Khan, Grigory Simin, X. Hu, J. Yang

Faculty Publications

The effect of the gate leakage current fluctuations on noiseproperties of AlGaN/GaN heterostructurefield effect transistors(HFETs) has been studied in conventional HFET structures and in AlGaN/GaN metal-oxide-semiconductorheterostructurefield effect transistors (MOS-HFETs). The comparison of the noiseproperties of conventional AlGaN/GaN HFETs and AlGaN/GaN MOS-HFETs fabricated on the same wafer, allowed us to estimate the contribution of the gate currentnoise to the HFET’s output noise. The effect of the gate current fluctuations on output noiseproperties of HFETs depends on the level of noise in the AlGaN/GaN HFETs. For the transistors with a relatively high magnitude of the Hooge parameter α∼10⁻³, even a …

Deformation And Limit Strain Analysis Of Superplastic Materials Using Finite Elements, Noha Mohamed Hassan

Archived Theses and Dissertations

No abstract provided.

Modeling Of A Meat Cooking Process For On-Line Monitoring And Control, Oralia Garcia

Theses and Dissertations - UTB/UTPA

A heat transfer model is developed to predict cooking time of meat patties given the initial temperature of meat, oven temperature, and meat properties to monitor and control a cooking process on-line. Experiments were performed to find the cause of variability in cooked weight and raw temperature effects in forming and final cooked temperature. Advanced charting techniques concluded that only common causes of variability were present in the process. Thermal conductivity experiments were performed to determine the thermal conductivity of meat (k), which was compared with the properties of meat published in literature to validate the experiment. Oven design analysis …

Strassen's Algorithm Made (Somewhat) More Natural: A Pedagogical Remark, Ann Q. Gates, Vladik Kreinovich

Departmental Technical Reports (CS)

Strassen's 1969 algorithm for fast matrix multiplication is based on the possibility to multiply two 2 x 2 matrices A and B by using 7 multiplications instead of the usual 8. The corresponding formulas are an important part of any algorithms course, but, unfortunately, even in the best textbook expositions. they look very ad hoc. In this paper, we show that the use of natural symmetries can make these formulas more natural.

Hybridization Of Dna By Sequential Immobilization Of Oligonucleotides At The Air-Water Interface, Murali Sastry, Vidya Ramakrishnan, Mrunalini Pattarkine, Anand Gole, K. N. Ganesh

Faculty Works

The hybridization of DNA by sequential electrostatic and hydrogen-bonding immobilization of single-stranded complementary oligonucleotides at the air-water interface with cationic Langmuir monolayers is demonstrated. The complexation of the single-stranded DNA molecules with octadecylamine (ODA) Langmuir monolayers was followed in time by monitoring the pressure-area isotherms. A large (and slow) expansion of the ODA monolayer was observed during each stage of complexation in the following sequence: primary single-stranded DNA followed by complementary single-stranded DNA followed by the intercalator, ethidium bromide. Langmuir-Blodgett (LB) films of the ODA-DNA complex were formed on different substrates and characterized using quartz-crystal microgravimetry (QCM), Fourier transform infrared …

Electrochemical Hydrogen Storage Properties Of Carbon Nanotubes, Xue Qin, Xue Ping Gao, Feng Wu, Hong Liu, Ying Lan, Hua-Tang Yuan, De Ying Song, Pan Wen Shen

Journal of Electrochemistry

The electrochemical properties of carbon nanotubes (CNTs) electrode have been investigated in this paper. The high discharge capacity of 200 mAh·g 1 was measured for the CNTs Ni electrode at a discharge density of 200 mA·g 1 . CNTs Ni electrode, the high electrochemical activity and the long cycle life were observed. The electrochemical mechanism of hydrogen adsorption and oxidation at the CNTs Ni electrode was studied by cyclic voltammertry method.

A Study Of Monitoring Corrosion Of Metal Via An Optic Waveguide Sensing Method, Xue Ming Li, Wei Ming Chen, Shang Lian Huang, Na Zhang, Zong-Qing Huang

Journal of Electrochemistry

An optical wave guide sensing method was proposed for monitoring corrosion of metal in outdoors steel structures. Replacing the cladding of wave guide with metal film in a particular location, the method takes the metal film as the corrosion sensitive film. The experiment of waveguide sensor was carried out on a 721 colorimetric vessel, with which the soution is held in itself and the light is propagated in its sidewall. A Fe C alloy film was electroplated onto the inner sied of vessel to form the corrosion sensitive film. The structure of the Fe C alloy film was studied by …

The Electrochemical Performance Of The Spinel Limn_2o_4, Shi Gang Lu, Yu Cheng Sun, Ren Min Liu, Wei-Hua Jin, Wen-Zhong Li, Cang Han

Journal of Electrochemistry

The cathode material spinel LiMn 2O 4 of lithium ion battery was synthesized by making use of solid state reaction at 750～850 ℃. The discharge capacity was 115～125 mAh g -1 . It was observed that the capacity loss increase at the elvated 55 ℃ temperature. A little excess Li content and the Co doped spined could improved the cycle capability of the cathode material. The dissolution of the spined in the electrolyte was measured. The treatment method was used to stabilize the LiMn 2O 4 structure. It was found that the spinel LiMn 2O 4, treated with layer compound …

The Study Of Pretreatment For The Determination Of The Conventional Anion In Sea Water By Ic——The Method Of Electrolysing Argentine Electrode, Lei Guo, Wei Yang, Rong Zong Hu

Journal of Electrochemistry

The method of pretreatment to determine trace amounts of Br ,NO 3 and SO 4 2 in sea water by ion chromatography was proposed, by which the electrolysing argentine electrode was used to minimize the disturbance of Cl -. The results indicate that the method is simple, convenient, quick and efficient with recovery rates over 95 percent.

Study On Electrodeposition Of Ingaas Thin Film, Yu Chun Li, Xi Lian Wang, Jing Ke Han, Ai-Zhen Han, Yuan-Kai Gao, Zhi-Wei Yang

Journal of Electrochemistry

The principle and the experimental method of the electrodeposition are discribed in detail in this paper.InGaAs thin film was prepared by using optimized electrodeposited conditions. The radiative wave length of the film was between 1.3～1.5 μm, the composition of the film was analyzed by energy spectrometer and the transmission spectrum of the film was measured by spectrophotometer and monochromator. The V I chractristic of the conductive type and the topography of the In x Ga 1 x As film were also studied.

A Study Of The Adsorption Behaviors On The Surface Of Gold Electrode By In-Situ Electrochemical Raman Spectroscopy, Xia Qin Wu, Xiao Wei Cao, Zhe Su Wang, Xiao-Yun Meng, Zong-Rang Zhang

Journal of Electrochemistry

The results of in situ measurements with Raman spectroelectrochemical thchnique on bare gold electrode and adenine modified gold electrode were reported. The adsorption behaviors of adenine and superoxide dismutase(SOD) and their interactions with gold electrode were analyed. The mechanism of promoted electron transfer process of SOD in the presence of adenine at gold electrode surface is discussed.

Studies Of Adsorption And Oxidation Of Ethanol On Nm-Pt/Gc Electrode——I.Cyclic Voltammograms And In-Situ Ftir Spectroscopy In Alkaline Media, Guo-Lian Chen, Shi-Gang Sun, Sheng-Pei Chen, Zhi-You Zhou

Journal of Electrochemistry

The electro_oxidation of ethanol on nm_Pt/GC electrode in alkaline solutions containing 0.02 mol·L -1 NaOH+0.1 mol·L -1 CH 3CH 2OH was investigated by using cyclic voltammetry and in_situ FTIR spectroscopy. The experimental results demonstrated that the main product of ethanol oxidation is CH 3COO -,only very small amount of CH 3CHO has been determined simultaneously. In contrast with the dual path reaction mechanism for the oxidation of ethanol in acid media,the oxidation of ethanol in alkaline media didn't pass through the dissociative adsorption,and no adsorbed species could be determined even using a nm_Pt/GC electrode that gives rise to enhancement of …

Electrochemical Polymerization Of Biphenyl And P-Terphenyl In Organic Solvent, Sheng Cui, Yun Yun

Journal of Electrochemistry

Polymers were prepared by oxidation of biphenyl and p terphenyl by consecutive cyclic voltammetry and at a constant potential in rigorously dried dichloromethane solutions. In situ studies on the polymerization properties and deposited polymer were also proceeded employing electrochemical quartz crystal micro balance, spectroelectrochemical measurements. The great mass deposition was observed as the biphenyl and p terphenyl monomers are oxidized indicating that polymers were formed by the oxidation of biphenyl and p terphenyl in the solution and then deposited on the platinum electrode surfaces. Polymerization can be further confirmed by the red shifts of spectra observed by spectroelectrochemical measurements. The …