Engineering Commons^™

Oodini 2.0 : An Enhances Graphical Schema Representation For Object-Oriented Database, Kamil Shahab

Theses

The graphical representation of object-oriented database (OODB) schemas is useful for The designers and users of a database system. The aim of our project was to enhance the existing version of OOdini, an interactive graphical tool for editing OODB schema. The new features include interactive modification and description of objects in the schema. Data structures for representing classes and attributes have been altered to incorporate object/data types as well as a descriptive string. The software has been implemented using ObjectMaker, a toolkit to design your own methodology using the ObjectMaker Extension Language.

Role Of Sympathovagal Imbalance In Syncope Using Heart Rate Variability Analysis, Jayadeep Krishnah Unni

Theses

One of the common and challenging problems confronting the physician in clinical practice is recurrent syncope. Despite extensive evaluations, the causes of these cases Of syncope are not found in more than 40% of the patients.

It is thought that most patients who experience unexplained syncope do so because of transient, unpredictable episodes of vasovagally mediated hypotension and bradycardia. It is hypothesized that impaired inhibition of parasympathetic tone during stress accompanies the development of syncope. Head-up tilt table testing reportedly provokes vasovagal episodes effectively in susceptible persons.

This study attempts to explain the role played by the sympathetic and parasympathetic …

Vibration Control On Linear Robots With Digital Servocompensator, Roger Kobla Kwadzogah

Theses

Control application for active damping of structural vibrations and acoustic noise in mechanical systems is one of the engineering fields that can benefit from advances made in digital signal processors. This thesis project is one such application. It is about a vibration control at the loading point of a high speed linear robotic workcell. A lead zirconate titanate piezoelectric ceramic is used as the actuator and an accelerometer provides the sensing. From experimentally measured frequency response of this system, a shaping filter is designed and added on. The reshaped system is fitted with a third order transfer function design model. …

Coagulation And Disinfection By-Products Formation Potential Of Dissolved Organic Matter Fractions, Neeraj S. Pipada

Theses

Both the proposed United States Environmental Protection Agency (USEPA) Disinfectants- Disinfection By-Products and Enhanced Surface Water Treatment rules have provisions for minimizing the formation of undesirable precursors of disinfection by-products (DBPs) in drinking water Natural Organic Matter (NOM) contains many of the precursors to the DBPs formed following disinfection of drinking water. DAX-8 resin procedures were used to isolate and fractionate NOM into six dissolved organic matter (DOM) fractions; Hydrophobic acid (FA), base (FB), neutral (FN), and hydrophilic acid (PA), base (PB) and neutral (PN). Aluminum sulfate (alum) jar coagulation tests were performed to determine the optimum coagulation ranges of …

Graphical User Interface For The Dsp : Using Texas Instruments Tms320c31 And Labview, Tahir Nazir

Theses

Digital Signal Processors (DSP's) have become very popular due to their ease of operation, economic value, adaptability and availability. However, the development environments for the DSP are still the archaic Assembly and C language programming. It is tedious, error prone and time consuming to develop and use DSP applications using these compared to Graphical User Interface development tools if available. In the modern age programming is very heavily done in object oriented graphical languages like the Visual C++ and Visual Basic. Windows also gives a good graphical user interface.

LAB VIEW with its readily available ensemble of good analysis, programming …

In Situ Enhancement Of Well Recovery By Pneumatic Media Injection, Michael Thomas Galbraith

Theses

The objective of this thesis was to develop a new process for enhancing recovery wells at hazardous waste sites. The process, known as an extended radius well (ERW), involves injection of ceramic beads directly into groundwater plumes to create drainage paths for liquid contaminants. This is a variant of Pneumatic Fracturing, which is a patented in situ remediation process developed to increase permeability of soil and rock formations by injection of high pressure gas.

The research study comprised laboratory investigations, engineering scale tests, and a field pilot demonstration. The laboratory investigations examined the properties of several candidate media to determine …

Computer Simulation Of Cerebrovascular Responses During Induced Hypotension, John A. Schalago

Theses

The purpose of this project was to develop a computer model of cerebrovascular hemodynamics interacting with a pharmacodynamic drug model to examine the effects of three commonly used anti-hypertensive drugs upon intracranial pressure and cerebral blood flow. The model is used to predict cerebrovascular response during the administration of commonly used anti-hypertensive agents.

The mathematical model of intracranial hemodynamics is a seven compartment constant volume system. A series of resistances relate blood and cerebrospinal fluxes to pressure gradients between compartments. Arterial, venous and tissues compliance are included. Autoregulation is modeled by transmural pressure-dependent arterial-arteriolar resistance. The effects of three drugs …

A Study On The Cathode Protection Potential Against Pitting Corrosion, Chun-Chun Xu, You-Ping Liu, Xiao-Bo Zhang, Xu-Hui Zhao

Journal of Electrochemistry

The methods have been developed to determine the protection potential against pitting corrosion. They are based on the theory that the pitting protection potential (E_p) is actually the transition potential of the direction of current between the occluded cell and the external surface (E_T). E_T lasts from -220 mV to -440 mV (SCE), the lowest of which can be considered as cathode protection potential. The E_p values determined with cyclic potentiodynamic polarization method is included in the E_T with above methods.

The Adsorption Stability Of Interface Corrosion Inhibitor, Fu-Xing Gan, Di-Hua Wang, Jin-Yun Zou

Journal of Electrochemistry

Some new results on the adsorption stability of interface corrosion inhibitor are presented. The concept of adsorption stability and the factors influencing the adsorption stability were discussed. It is shown that the anodic desorption potential can be employed to evaluate the adsorption stability of the inhibitor as an empirical character in some conditions. Electrochemical oscillations phenomena were observed for the first time on a rotating iron electrode in H₂SO₄ solution containing organic inhibitor in the active potential region. These potentiostatic current oscillations can occur under cathodic polarization, as well as under anodic plarization. The oscillation period, amplitude, …

The Behaviors Of Capacity Loss Of Limn2O4 Cathodeat Elevated Temperatures, Xiao-Hong Hu, Han-Xi Yang, Xin-Ping Ai, Sheng-Xian Li, Xin-Lin Hong

Journal of Electrochemistry

The capacity loss of spinel LiMn₂O₄ cathode at elevated temperatures was evaluated by constant current charge-discharge methods and it was found that serious capacity loss and cycleability decrease occured at above 50, especially for the charged cells. The mechanisms for this phenomena were examined by atomic emission and infrared spectrometry of the electrolyte, XRD measurment of the cycled elecrode and microelectrode voltammetry of LiMn₂O₄ at room and elevated temperatures. The results showed that with increasing temperature, Mn and Li ions tended to redistribute partly in the spinel framework due to the disproportion of Mn …

Study On The Microband Array Electrode-Based Glucose Microsensor, Neng-Qin Jia, Chui-Jue Sun, Lin Gao, Zong-Rang Zhang, Jian-Zhong Zhu, Guo-Xiong Zhang

Journal of Electrochemistry

The microband array electrode (MAE) consisting of 11 Pt microband of 5 m in wide, 2000 m long and 85 m gap was fabricated with a thin film techology. The MAE was characterized by means of cyclic voltammetry in a solution of K₃Fe(CN)₆ and H₂O₂. The results showed higher current density on MAE than on conventional Pt eletrode due to the strong edge effect of the former. A glucose microsensor was constructed with the substrate electrode of microband array. Microband array electrode was modified by Nafion followed by the immobilization of ferrocene onto …

Oxidation And Adsorption Of Deoxyribonucleic Acid At Highly Ordered Pyrolytic Graphite And Glass Carbon Electrode, Jian-Zhang Zhou, Ling-Ling Wu, Jin Luo, Zhong-Hua Lin

Journal of Electrochemistry

It is shown that calf thymus DNA (CT DNA) can be adsorbed at highly ordered pyrolytic graphite (HOPG) electrode and detected by differential pulse voltammetry (DPV) and electrochemical atomic force microscopy (ECAFM). It is found that controlled potential pre-polarization influences largely the adsorption of dsDNA while it has little influence on ssDNA. It is demonstrated that ECAFM is useful to exploit adsorption of DNA at HOPGE. The pattern of adsorption of DNA at HOPG electrode that fits best with the experimental data is proposed. The results aslo shows that UV/Vis reflection spectroscopy, which has not been used in studying electrochemical …

Influence Of Ptfe And Nafion On The Utilization Efficiency Of Pt/C Catalyst In Pemfc, Xiao-Liang Cheng, Bao-Lian Yi, Jing-Xin Zhang, Ming Han, Ya-Guang Qiao

Journal of Electrochemistry

With cycling voltammetry curve(C-V), TEM and SEM photographs, the influence of PTFE and Nafion on the platinum utilization in catalyst layer of PEMFC was investigated. The results show that in gas diffusion electrode, the blocking effect of PTFE in the platinum utilization is not pronunced. In the thin-film catalyst layer, the electron conduct of the catalyst was blocked by the nafion solid and this caused the decrease of platinum utilization. With the increase of the nafion content in the catalyst layer, both platinum utilization and the electron conductivity decreased in the catalyst layer. Because the molecule size of nafion is …

Preparation And Application Of Gold-Film On The Surface Of Bacterial-Modified Carbon Paste Electrode, Rong-Zong Hu, Yan-Ping Ruan, Hao Xu, Jin-Kun Fu, Wei-De Zhang, Wen-Yun Hu

Journal of Electrochemistry

A novel method for preparation of gold-film composed of ultra-fine gold particles was reported in this paper. The gold-film was prepared by electrochemical method on the surface of the paste electrode modified with the strain Bacillus sp. D01 which has strong ability to absorb and reduce Au³⁺. In addition, this paper reported an experimental method of determining trace amount of Cu²⁺ in water solution using cathodic stripping analysis to estimate the performances of the obtained gold-film. The experimental results indicated that this new method for preparation of gold-film is simple. The obtained gold-film electrode is stable and …

The Influence Of Heat On The Measurement Of Photocurrent At The Anodic Film Of Nickel Electrode, Hang Chen, Zhi-Yu Jiang

Journal of Electrochemistry

The influence of heat on the measurement of photocurrent for nickel electrode in 1 mol/L NaOH solution was investigated by using the photocurrent, photothermal and thermal current methods. It was found that the appearance of photocurrent in potential region of -0.75~0.20 V (vs. Hg/HgO electrode) was due to the p-type semiconductor properties of Ni(OH)₂ film in which is agree with the previous report. In the Ni(OH)₂/NiOOH redox potential region, the increase of temperature at the surface of working electrode during irradiation significantly promoted the electrochemical reaction strongly. The photocurrent observed in potential region 0.20~0.57 V is mainly …

Effects Of Nickel Content And Simulated Heat Affected Zone Of 2205 Duplex Stainless Steel On Pitting Corrosion, Horng-Yih Liou, Ju-Tung Lee, Wen-Ta Tsai, Rong-Iuan Hsieh, Yeongtsuen Pan

Journal of Electrochemistry

The effects of nickel content and Gleeble simulated heat affected zone (HAZ) of 2205 stainless steel on pitting corrosion were investigated in this paper. The results showed that nickel content, ranging from 4.5 wt% to 6.5 wt% in base metal, had only a minor effect on the electrochemical polarization curves, with all E_np's and E_pp's falling in the rang of 1100~1200 mV. Comparing with the base metal, the simulated HAZ microstructure caused an increase in the anodic current density, a distinct decrease in both E_np and E_pp , and a reduction in the passive …

The Influential Factors On The Triboelectrochemical Behaviors Of The Passive Alloys, Dong-Bai Sun, Tao Li, Hong-Ying Yu, De-Jun Yang

Journal of Electrochemistry

The tribocorrosion process of Fe-Cr alloys with different Cr content in H₂SO₄ solution was investigated. The influence of applied load, friction velocity, Cr content and concentration of H₂SO₄ in solution on the triboelectrochemical behaviors of the alloys was analyzed. It is shown that applied load and friction velocity have singnificant influence on the tribocurrent density in passive region when friction process occurs on part of the surface of alloy. Increasing the corrosion resistance of alloys or decreasing the aggressive of the solution can reduce the alloy removal velocity.

Investigation Of Solution Chemistry In Crevice Of Carbon Steel And Its Anodic Polarization Behavior, Zhuo Chen, Cui-Wei Du, Bei Cao, Yin-Shun Wu, Hai Yang, Zheng-Rong Zhang

Journal of Electrochemistry

A self-made wedge-shaped simulated crevice apparatus was designed to investigate the solution chemistry in crevice of carbon steel and its anodic polarization behavior. For carbon steel with 3.5%(wt) NaCl, the change and the distribution of electrode potential, concentration of Cl^- and pH value of solution in the crevice, and the current density of metal in the crevice were measured respectively under various conditions of anodic polarization. The results showed that without polarization the metal about 2 cm away from the opening of the crevice was attacked preferentially because of its lowest free corrosion potential. The anodic polarization promoted the …

Zro2 And Zro2-Y2O3 Coatings Deposited By High Energy Pulse, Wei-Ping Yu, Ye-Dong He, Li-Na Zhang, De-Ren Wang

Journal of Electrochemistry

The basic rule and influence factors on deposition of ZrO₂ and ZrO₂-Y₂O₃ coatings by high energy pulse were studied. After the oxidizing experiment in air at 1 000 for 100 h, it was shown that the oxidation resistance of 18-8 stainless steel was marketly enhanced by depositing ZrO₂ and ZrO₂-Y₂O₃ coatings. The oxidation resistance was increased about 20 times and the oxide scale spallation resistance was increased about 100 times.

Electrochemical Behavior Of Riboflavin On Glassy Carbon Electrode, Hong Li, Lin-Cai Jiang, Liang-Nian Ji

Journal of Electrochemistry

The electrochemical behavior of riboflavin(RF) on glassy carbon has been investigated by using potential sweep, rotating ring-disc electrode and the measurement of differential capacitance. It is shown that a single well-behaved oxidation-reduction wave corresponding to a reversible two-electrons reaction apears in medium of pH<6, and the adsorption of RFH₂ formed by electro-reduction is weak and hence its solubility is good. In medium of pH>6, there are two separating but overlapping partly oxidation-reduction waves corresponding to two-step one-electron reaction. The adsorptions of RFH and RFH₂ produced by reduction reactions in medium of 6

Study On The Hydrogen Permeation Through Zinc Electrodeposit, Jiang-Li Cao, Ji-Xun Wu, Yan-Ping Lu, Jie Shi

Journal of Electrochemistry

The electrochemical hydrogen-permeation technique was used to study hydrogen permeation through zinc electrodeposit with bilayer specimens of Fe substrate/zinc electrodeposit. The effect of coating thickness on hydrogen diffusion coefficient and hydrogen steady-state flux was studied. The results showed that hydrogen diffusion coefficient was approximately in the range of 10-11 cm²·s^-1 rank and zinc coating could retard hydrogen permeation. Accordingly, hydrogen steady-state flux and effective diffusion coefficient declined while the coating thickness increased.

In Situ Ftir Spectroelectrochemical Study Of Palladium Hexacyanoferrate Thin Film Deposited On Glassy Carbon Electrode, Ai-Li Bo, Xiang-Qin Lin

Journal of Electrochemistry

The electrochemically deposited Palladium hexacyanoferrate thin film on Glassy Carbon electrode (PdHCF|GC) has been studied in HCl, KCl and NaCl solutions by in-situ external reflection FTIR spectroelectrochemical technique. It is found that the behavior of the electroactive PdHCF film can be understood in terms of two states: Pd₂Fe(II)(CN)₆ formed in the inner layer and (M⁺)2Fe(II)(CN)₆ (M⁺: electrolyte cation) formed in the outer layer. The inner layer is oxidized at E_m=0.87 V in 1 mol/L KCl, while for the outer layer Em=0.77 V(vs. Ag/AgCl). In 1 mol/L NaCl or HCl solutions, …

Effect Of Inhibitor On Electrochemical Behavior Of 1cr18 Stainless Steel In Acidic Solution Under Friction, Jin-Ping Xiong

Journal of Electrochemistry

The electrochemical behavior of 1Cr18 stainless steel had been studied using a reciprocating triboelectrochemical equipment under friction in 0.2 mol/L H₂SO₄ solution with and without addition of thiourea, the frictionized surface of 1Cr18 stainless steel had been examined by the SEM, XPS and IR. The results showed that the loss rate of 1Cr18 stainless steel in the solution could be reduced by addition of thiourea. The adsorption of thiourea on the surface of 1Cr18 stainless steel prohibited the oxidization of Cr³⁺ to form Cr(Ⅵ) and formation of passive film consisting of CrO₄^2- or/and Cr(Ⅵ), …

Z-Protected Glutamic Acid-Based Biodegradable Thermoplastic And Thermosetting Polyesters: Synthesis And Characterization, R. M. Tadros, Hossein Noureddini, Delmar C. Timm

Papers in Biomaterials

Biodegradable polymers were formed from N-benzyloxycarbonyl-L-glutamic acid with the comonomers ethylene glycol, diglycidyl ether of 1,4-butanediol, and diglycidyl ether of bisphenol A. The three polymers were a linear and a cross-linked heterochain polyester and a cross-linked polyester that contained aromatic units within its network chains. The thermoplastic resin and the soluble fractions for the thermosetting resins were characterized by gel permeation chromatography. Conversions for carboxylic acid were determined by titrations. A quality, 22,000 molecular weight thermoplastic resin was formed. The two thermosets were cured past their gel points. Gelation analysis revealed that the relative rate constants for the sequential oxirane/acid …

Method Of Coupling Ligands Onto Supports And Products Produced Therefrom , William H. Velander, Anuradha Subramanian

Department of Chemical and Biomolecular Engineering: Patents

A method is disclosed for coupling a ligand within a porous support. The method involves mixing ligand and porous support under conditions sufficient to suppress coupling conditions of the ligand to the porous support while enhancing the relative rate of diffusion, to the rate of reaction, of the ligand into and within the porous support, and then altering the conditions to enhance rapid coupling of the ligand within the porous support. The alteration from diffusion conditions to coupling conditions involves a change in the reaction solution of pH, ionic strength, temperature, coupling competitor, such that a relatively lower Thiele Modulus …

Method Of Coupling Ligands Onto Supports And Products Produced Therefrom , William H. Velander

Department of Chemical and Biomolecular Engineering: Patents

A method is disclosed for coupling a ligand within a porous support. The method involves mixing ligand and porous support under conditions sufficient to suppress coupling conditions of the ligand to the porous support while enhancing the relative rate of diffusion, to the rate of reaction, of the ligand into and within the porous support, and then altering the conditions to enhance rapid coupling of the ligand within the porous support. The alteration from diffusion conditions to coupling conditions involves a change in the reaction solution of pH, ionic strength, temperature, coupling competitor, such that a relatively lower Thiele Modulus …

Sensors Location Effect On The Dynamic Behaviour Of The Composite Structure With Flaw Detection, Eltahry Elghandour, Faysal Kolkailah, Abdel- Hamid I. Mourad

Aerospace Engineering

In this paper presents an experimental and numerical investigation ofthe natural frequency of composite material cantilever plates. The stacking sequence of tbe composite plate is Quasi-isotropic laminated plate is [2(0j/±45°/2(90°)]" The plate was subjected to incremental cuts and tests to determine changes in new modal properties. The study included white noise and sinusoidal dynamic testing techniques and a virtual instrument dynamic analyzer. In this study also, determining the resonant frequencies of the undamaged and damaged plate, and evaluating the capabilities of piezoelectric ceramics (PZT's) for fault detection based on their sensitivity and accuracy changes in modal parameters. Numerical results are …

Mixed Mode Stable Crack Extensions Through Stiffened Specimens, Abdel-Hamid I. Mourad, Eltahry Elghandour, Faysal A. Kolkailah

Aerospace Engineering

This study presents an experimental investigation of fracture mechanics for isotropic material, aluminum alloy D16AT. The problem of stable crack growth (SCG) has been addressed in this paper. Experimental results are presented for symmetrically stiffened and unstiffened three point bend specimens subjected to different modes, mode I and mixed mode. The stiffeners are doubly bonded to the fatigue pre-cracked specimens parallel to the length at a certain distance behind the crack tip using an adhesive Redux 410 NA. Results concerning load displacement variation, growth of plastic zones, instantaneous crack edge profiles, and tunneling are presented. There is evidence that the …

The Magnetic Excitation Spectrum And Thermodynamics Of High-Tc Superconductors, Pengcheng Dai, Herbert A. Mook, Stephen M. Hayden, Gabriel Aeppli, Toby G. Perring, Rodney Dale Hunt, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Inelastic neutron scattering was used to study the wave vector– and frequency dependent magnetic fluctuations in single crystals of superconducting YBa₂Cu₃O_6+x. The spectra contain several important features, including a gap in the superconducting state, a pseudo gap in the normal state, and the much-discussed resonance peak. The appearance of the pseudo gap determined from transport and nuclear resonance coincides with formation of the resonance in the magnetic excitations. The exchange energy associated with the resonance has the temperature and doping dependences as well as the magnitude to describe approximately the electronic specific heat near …

The Magnetic Excitation Spectrum And Thermodynamics Of High-Tc Superconductors, Pengcheng Dai, Herbert A. Mook, Stephen M. Hayden, Toby G. Perring, Gabriel Aeppli, Rodney Dale Hunt, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Inelastic neutron scattering was used to study the wave vector– and frequency dependent magnetic fluctuations in single crystals of superconducting YBa₂Cu₃O_6+x. The spectra contain several important features, including a gap in the superconducting state, a pseudo gap in the normal state, and the much-discussed resonance peak. The appearance of the pseudo gap determined from transport and nuclear resonance coincides with formation of the resonance in the magnetic excitations. The exchange energy associated with the resonance has the temperature and doping dependences as well as the magnitude to describe approximately the electronic specific heat near …