Engineering Commons^™

The Effect Of Electrodes On The Thermally Stimulated Currents In Sodium Silicate Glass, Ruth Mogrovejo Cuzmar

Masters Theses

“Electrodes play an important role in the study of alkali ion motion in glasses when TSPC/TSDC techniques are used. Silver, gold and combinations of them were used in the study of Na⁺ motion in Na₂O·3SIO₂ glass. The lower temperature peak is not affected by any of these electrodes, so it is attributed to the bulk glass. A second and third peak are strongly dependent on the kind of electrode used. A gold anode is a blocking electrode, and a gold cathode, is partially blocking. There is a tendency for a space charge polarization to form when …

Sintering Of Catio₃ With The Addition Of Caco₃ And Lif, Surapol Pleekram

Masters Theses

"The densification of CaTiO₃ with the addition of 4.74, 5.90, 6.88 mol% CaCO₃ and 22 mol% LiF was investigated over the temperature range 800° to 1050°C, for sintering times ranging from 1 to 216 hours. It was found that CaCO₃ reacts with LiF and to form a liquid at a temperature of about 450°C. This liquid enhances the densification of CaTiO₃ . The densification process was followed by making weight loss, shrinkage and porosity measurements. The microstructural development was determined by scanning electron microscope examination of both fractured and polished surfaces. X-ray diffraction and DTA/TGA were …

An Evaluation Of Magnetic Field Shielding And Cross Talk For Various Cable Configurations, Amir Hossein Nafar

Masters Theses

"The effect of shield grounding on magnetic field coupling in coaxial and twisted pair cables, was studied for various positions of the ground connection at 50 KHz. For the case of only one end of shield grounded the attenuation was about 60 dB. Furthermore, the effect of frequency from 50-500 KHz was considered on three cases. Thus it was concluded that attenuation increases as frequency increases. A combined experimental and analytical investigation was also conducted to characterize the mechanism of cross talk between wires of ribbon cable and traces on printed circuit boards. Inductive and capacitive coupling were studied in …

The Effect Of The Degree Of Saturation On The Permeability Of A Compacted Clay To Organic Permeants, Mark Alan Harms

Masters Theses

"Relationships for permeability of kaolinite versus degree of saturation and permeability versus flow are developed for 0.005 N calcium sulphate, xylene and aniline permeants using the triaxial flexible wall permeameter. The clay was statically compacted at degrees of saturation of 50%, 75% and 100%. A gradient of 277 was used for the permeability tests.

The initial degree of saturation was inversely related to the permeability of the clay. Saturated clay samples were found to be virtually impervious to aniline and xylene. As the degree of saturation decreased, the permeability increased with the initial volume of flow equivalent to the volume …

Evaluation Of Low Temperature Properties Of Gas Oil, Dina Atef Abd El Ghaffar

Archived Theses and Dissertations

No abstract provided.

Final Design Report Of The Design Of A Climate Controlled Sleeping Chamber For Infants And Toddlers, Jennifer Stenger Stevens

Undergraduate Honors Capstone Projects

A climate controlled sleeping chamber, or air crib, for infants and toddlers is an alternative sleeping medium to the conventional crib. It is a chamber that is ventilated with air that is temperature and humidity controlled to provide an optimum sleeping environment for young children, ages 0 to 2 years. Its purpose is to enhance the psychological and physiological development of young children. Because it is easier to heat a small chamber than larger living quarters, the air crib also has economic advantages.

The design o climate controlled sleeping chamber must meet some minimum requirements. The system must provide an …

A Computational Model To Estimate The Thickness Of The Waterfilm Due To Rain On The Upper Surface Of An Airfoil, Padmanabha R. Chappidi

Retrospective Theses and Dissertations

Based on a two-phase boundary layer approach, a computational model is proposed to estimate the thickness of the waterfilm due to rain on the upper surface of an airfoil. The coupling between the air boundary layer and the water film is established by the conservation of mass and momentum at the interface. By a simple coordinate transformation, the interface is conformed to the finite difference grid system. Trajectory analysis of a raindrop of 1 mm diameter shows that the impingement of drops is high near the leading edge of the airfoil and decreases downstream. The finite difference equations of air/waterfilm …

Dissolution Of Multi-Component Systems, Robin Ashley Murphy

Doctoral Dissertations

"The validity of ideal barrier layer diffusion kinetics was examined in the NaCl/KCl - glycerol and Al₂O₃-CaO-Al₂O₃-SiO₂/slag corrosion systems. Single crystals and dense polycrystalline plates of pure NaCl or KCl exhibit steady-state corrosion rates within 10%, of calculated theoretical values, while dense mixtures of the two salts corrode at rates higher than either pure material. The results are compared to the grooving phenomena of NaCl/KCl bicrystals.

Polycrystalline Al₂O₃ is shown to corrode at the same rate as single crystal sapphire at 1400°C in CaO-SiO₂-Al_{2 …}

Two New Parallel Processors For Real Time Classification Of 3-D Moving Objects And Quad Tree Generation, Farjam Majd

Dissertations and Theses

Two related image processing problems are addressed in this thesis. First, the problem of identification of 3-D objects in real time is explored. An algorithm to solve this problem and a hardware system for parallel implementation of this algorithm are proposed. The classification scheme is based on the "Invariant Numerical Shape Modeling" (INSM) algorithm originally developed for 2-D pattern recognition such as alphanumeric characters. This algorithm is then extended to 3-D and is used for general 3-D object identification. The hardware system is an SIMD parallel processor, designed in bit slice fashion for expandability. It consists of a library of …

A Study Of Shadow Contrast For A Grating, Steve Eugene Watkins

Masters Theses

"A theoretical and experimental investigation of the causes of the reduction of the contrast in the shadow of a grating has been made. The variation of the shadow contrast is shown to be different for the two causes--diffraction and divergence. The conditions which determine the dominant effect are presented. Also, the contrast pattern due to diffraction is shown to have a squared scaling law while the divergence pattern is shown to scale linearly. This understanding of the shadow contrast increases the versatility and usefulness of the shadow moire technique, an optical method for determining the topography of surfaces"--Abstract, page ii.

Automated Evaluation Of Reservoir Parameters Applying Pressure Transient Theory, Steven Robert Homoky

Masters Theses

"This study presents an investigation to automatically evaluate reservoir parameters using pressure transient theory. Methods will be introduced to numerically fit the well test data in the real (time) domain (specifically the pressure change as a function of test time). The numerical fit and known fluid, rock and well properties will be used to evaluate the dimensionless storage coefficient. The theoretical dimensionless pressure (being a function of skin factor, permeability, and dimensionless storage coefficient) is obtained by Laplace Inversion. The ability to evaluate the dimensionless storage coefficient thus reduces the parameters of the pressure equation by one. Varying the skin …

Evaluation Of A Near-Surface Low-Level Radioactive Waste Disposal Facility For The State Of Missouri, Christine Lang Nelson

Masters Theses

"A low-level radioactive waste disposal facility for the state of Missouri Is designed. The proposed facility Is to be placed in a mined opening within a Precambrian granite outcrop in southeastern Missouri.

A safety assessment of the proposed facility was performed. The method used was fault tree analysis.

The threat of seismic activity within the region ls seen to be the main determent to the proposed design. Groundwater modelling was not possible due to a lack of data.

The facility design Includes a provision for the retrieval of the low-level waste once the waste has decayed to acceptable levels"-- Abstract, …

Development Of Apparatus For Constant-Hydraulic-Gradient And Constant-Rate-Of-Strain Consolidation Tests, Jack F. Geerlings

Masters Theses

"A back pressure type consolidometer manufactured by Anteus Laboratory Equipment Company is modified to perform either constant hydraulic gradient or constant rate of strain consolidation tests. The modification of the consolidometer and its instrumentation are described. Computer software is developed for the purpose of apparatus control and for test data acquisition and analysis.

Constant hydraulic gradient and constant rate of strain consolidation tests are performed on samples consolidated from a slurry in the laboratory. Results of these tests are compared with incremental consolidation tests performed with an oedometer.

The modified apparatus was found to be suitable for use in both …

Oxygen Absorption And Diffusion In Tissue, Bo Henrik Arve

Masters Theses

"A mathematical model which describes the diffusion of oxygen in absorbing tissue is presented. The model accounts for the presence of a moving boundary which marks the deepest penetration of oxygen into the absorbing medium and predicts the steady state and unsteady state distribution of oxygen through the absorbing tissue.

Results are shown for zeroth, half, first, one and a half, and second order rates of absorption as well as when the rate of absorption is described by the Michaelis - Menten equation.

The model predictions show that the total time for the moving boundary to recede to the surface …

Electric And Magnetic Field Induction On Parallel Transmission Lines, Robert Joseph Schnell

Masters Theses

"The theory behind electric and magnetic field induction is developed. The theory is then applied to the calculations of induced voltages and currents on a de-energized three phase transmission line paralleling an energized three phase transmission line. The effect of shield wires on the induction phenomena is explained. Interactive computer programs for both electric and magnetic field induction are presented and instructions given for their use. Both programs are stored on disks and are for use on an IBM (or compatible) personal computer. Example problems are posed and solved"--Abstract, page ii.

A Theoretical Study Of Antecedent Soil Moisture As It Relates To The Rainfall-Runoff Relationship, Karen Sue Angert

Masters Theses

"This paper addresses the feasibility of using antecedent soil moisture as a tool for predicting the extractions from rainfall due to the infiltration process by solving the one-dimensional equation for saturated- unsaturated flow through porous media. Soil moisture characteristics in the form of empirical equations were used to incorporate the hysteretic behavior of the soil-water relationships into the model. Two sets of parameters were developed to be representative of a silty sand and a silty fine sand.

Extractions as infiltration from a given storm hyetograph and the total volume of direct runoff were computed for different initial moisture states. When …

A Management Training Model For Engineers In Saudi Arabia, Majid Al-Kassabi

Doctoral Dissertations

“Great economic growth has occurred in Saudi Arabia in the last decade creating overwhelming demands for professionally trained people. The emerging Saudi professionals are mostly engineers who have been put in managerial positions without the benefit of managerial training.

Objectives of this research were 1) To identify the skills needed by engineers to become managers; 2) To identify problems and constraints inherent in management training programs; 3) To identify the impact of a model training program on the individual; and 4) The impact of a model training program on the firm.

A training program was implemented using an experimental group …

An Analysis Of Mill Sound Levels To Aid In The Control And Understanding Of The Grinding Process, Scott Douglas Morrison

Doctoral Dissertations

“An experimental study has been made to evaluate the relationships between grinding parameters and the directional sound levels emitted from the collision of the grinding media with the mill wall for a laboratory batch ball mill.

Discrete frequency and single frequency band sound pressure level measurements were performed to investigate the changes in sound levels with grind time. It was demonstrated that the reduction in sound levels with grind time observed for a narrow sized feed can be used to indicate optimum breakage rates, overall time-based particle size distribution, and ore character.

The relationships established with the discrete frequency and …

Numerical Simulation Of Mixing Processes In Two-Dimensional Channel Flows, Milan Karel Straka

Doctoral Dissertations

"Recently, considerable interest has arisen in the numerical simulation of laminar and turbulent transport phenomena. More knowledge in this field is needed to improve predictions of heat and mass transfer processes in a variety of technical fields.

In this work a new computationally efficient transport model is developed. It consists of partially parabolized time-dependent equations of motion, continuity, and concentration of nonconservative species. Pertinent equations are solved numerically for both laminar and turbulent flow.

Results of calculations of laminar flow in the entry region of a parallel-plate channel agree well with the work of other authors. For turbulent flows, the …

Kinetics And Reactor Design In The Pyrolysis Of Tar Sands, Charles Arthur Lechner

Doctoral Dissertations

"Data from the thermal decomposition of bitumen from Utah tar sands was obtained and analysed with both isothermal and non-isothermal chemical reaction models. The use of a power rate law to describe the complex kinetics of pyrolysis gave agreement with the experimental data that was approximate, but adequate for design purposes. The results indicated a reaction rate that was second order in bitumen content, with an activation energy of about 17 to 20 kcal/gmol.

Data for the boiling point distribution of the products was consistent with a change of mechanism from vaporization to pyrolysis as the samples are heated. Higher …

Electrochemical Evaluation Of Zinc Electrolyte, Rajesh Kumar Singh

Doctoral Dissertations

"The polarization characteristics of acidified zinc sulfate electrolyte with varying solution chemistries were examined by cyclic voltammetry. An attempt was made to correlate the polarization results with the morphological and current efficiency data in order to develop a better understanding of the more fundamental aspects of impurity and additive behavior during the zinc electrodeposition process.

A statistical screening design program was conducted to determine the effects of certain operating parameters on the nucleation potential of zinc from sulfate electrolyte. The variables studied included: solution temperature, H₂SO₄ and Zn concentration, and scan rate. The solution temperature was found to be the …

Mass Transport Considerations In Electrometallurgical Reactions, Jose Rolando Sami Cuzmar

Doctoral Dissertations

"The research program described is divided into three segments. In the first part, the morphology and kinetic studies of Cd²⁺ removal from ZnSO₄ solutions using Zn dust as a reducing agent are presented. In the absence of impurities, the morphology of the Cd deposit shows the formation of two-dimensional or leaf-like dendrites capable of interlocking and forming agglomerates or balls. The size and strength of the agglomerates depend on the initial Cd²⁺ concentration to Zn metal surface area ratio, the rate of Cd ²⁺ removal, and the reactor geometry. The presence of additives, like Cu²⁺ and …

Transient Flow Inverse Study Calculation Of Unsaturated Permeability Of Wood, Farid Piroozmandi

Dissertations and Theses

One of the major processes in lumber industry is wood drying. This process consumes large amounts of energy and capital, and due to the length of time it takes, it acts as a governing factor in lumber production levels. Development of improvements in processes and equipment used in wood drying can be expedited through computer simulation of various drying procedures. These numerical simulations depend on the accuracy of numerical models representing wood transport properties, including functional dependency of liquid permeability through wood with respect to local saturation level. Data available in the literature mainly represent wood permeability properties at fully …

The Direct Summation Of Totally Self-Checking Checkers, Stefean Andrew Fedyschyn

Electrical & Computer Engineering Theses & Dissertations

A new technique for reducing the complexity of designing Totally Self-Checking (TSC) checkers for m-out-of-n codes is presented. The method is based on the partitioning of the input variables into r classes, then partitioning the code groups generated into Z output partitions. Comparison with earlier results reveals improvements in design simplicity and logic and testing complexity.

This thesis also presents a new method of TSC checker design where a j-level m₁/n₁ code and a k-level m₂/n₂ code TSC checker are directly summed to form a max [j,k]-level (m₁ + m₂) / …

Long-Term System Performance Of A Direct Expansion Solar Assisted Heat Pump, Majid Abazeri

Mechanical & Aerospace Engineering Theses & Dissertations

The long-term thermal performance of a direct expansion solar assisted heat pump is determined from the transient system simulation of the system. The system employs a bare collector which also acts as the heat pump evaporator. Of particular interest in this study is the

configuration in which the compressor and the collector area are properly matched from the long-term thermal performance viewpoint. This matching is achieved through continuous as well as two step compressor capacity modulation. In addition to examining the effects of compressor capacity modulation, the effects of various system parameters such as collector area„ storage volume, load temperature, …

Computer Aided Simulation Of A Heating, Ventilating, And Air Conditioning System In A Building, Sunil Shrikrishna Kulkarni

Mechanical & Aerospace Engineering Theses & Dissertations

The Godwin Life Science Building on the Old Dominion University campus presents an interesting problem in terms of energy conservation. The building is the maximum energy resource consumer on the campus, having a criterion value of 234 KBtu/sq.ft-year (2657 MJoules/sq. rneter-year). A Simplified Energy Analysis Method (ASEAM) loads and systems computer program was used to simulate the building and its heating, ventilating, and air conditioning (HVAC) plant in order to understand the building's high annual energy resource consumption rate, and to devise ways to overcome it. The main goal was to assess and propose energy conservation improvements to the existing …

Development Of Dynamic Testing Machine For Laboratory Modeling Of The Rock Fracturing Phenomenon, Mohammad Ali Moghaddass Zadeh Kermani

Theses

The purpose of this thesis is to develop a dynamic testing machine for laboratory modeling of the rock fracturing phenomenon. Bearing stratum fracturing is a construction difficulty which occurs when end-bearing piles are driven to weak rock or weathered sound rock. It is a pile group effect and can result in significantly less pile carrying capacity than the final driving resistance would normally indicate.

A linear scaling factor was derived to establish similitude between the laboratory apparatus and field conditions. This scaling factor is approximate and was used for overall sizing of the apparatus and its components. A more exact …

Load Flow And Contingency Analysis In Power Systems, Kianfar Sorooshian

Dissertations and Theses

A load flow and contingency analysis program for secure design, planning and operation of power systems. Depending on the application either Newton-Raphson or Fast-Decoupled method is employed to solve the load flow. Fault analysis is done by Z bus method. Contingency analysis may be done following the load flow solution by Fast-Decoupled method. The program is also interfaced with a graphic system which displays a single line diagram of the system on the graphic screen along with relevant data and informs the operator of any change by flashing the faulted bus or the line outage.

Study Of Longitudinal Landing Flying Qualities Evaluation Using Pilot Model Theory, Eric D. Didomenico

Theses and Dissertations

Control Anticipation Parameter (CAP), used in MIL-SPEC-8785C as a longitudinal handling qualities criterion does not adequately distinguish between different flight phases. Recent flight test data from the Landing Approach Higher Order Systems (LAHOS) study further indicate the inadequacy of the second order approximations for higher order longitudinal landing flying qualities. Nine Aircraft that fall within the Level 1 boundary reveal pilot ratings ranging from 1.5 to 10 (Cooper/Harper). These nine aircraft are studied by combining their longitudinal dynamics with pilot modelling to examine a better method of landing flying quality prediction and evaluation. Pilot model theory (cross-over pilot model) is …

Solution To Eigenvalue Problems Of Antisymmetric Cross-Ply And Antisymmetric Angle-Ply Laminated Plates Using Affine Transformations, Zaffir A. Chaudry

Theses and Dissertations

Using affine transformations and suitably recasting the buckling vibration differential equations, the eigenvalue problem of anti-symmetric cross-ply and antisymmetric angle-ply laminated rectangular plates has been reduced to a function of two strong material constants, the generalized rigidity ratio, whose range is in the closed interval from 0 to 1, and the ratio of principal lamina stiffness. With the reduction in number of constants an exhaustive parameter study of buckling and vibration solution trends, is possible. The buckling coefficients decrease with decreasing value of generalized rigidity ratio for both antisymmetric cross-ply and antisymmetric angle-ply laminates. For a given aspect ratio, and …