Engineering Commons^™

Investigation Of Velocity Distribution Within High Speed Waterjet, Hong Cao

Theses

The aim of this research was to investigate velocity distribution within the water jet at different conditions of jet formation. The water jet (WJ) velocity was measured by the use of Laser Transit Anemometer (LTA) and statistical technique which improved the accuracy of the velocity determination.

The velocities were measured for different diameters of the sapphire nozzle under different water pressures at different axial stand off distances and radial distances across the jet. The experiments performed in this study enabled us to evaluate the effects and conditions of the water jet on the velocity distribution. The acquired results provide information …

A Comparison Between Revealed Preference (Rp) And Stated Preference (Sp) Based On Results Of Simulations, Qiuzi Chen

Theses

This research quantifies the potential biases resulted from two different data generation methods used in transportation modeling: Revealed Preference (RP) and Stated Preference (SP) techniques. Revealed Preference technique is the conventional approach to generate data. It relies on observed or reported data of actual behavior. Stated preference technique is a new data generation method. It creates transportation scenarios using hypothetical data. Conventional studies favor the use of revealed reference. However, full description of advantages and weaknesses of using revealed preference technique is not available in literature, neither point-to-point comparison between stated preference and revealed preference techniques. This research contributes to …

Performance Evaluation And Sequence Control Of An Automatedmanufacturing System, Vijaykumar D. Desai

Theses

In an automated sequential manufacturing system Programmable Logic Controllers (PLC) are widely used. As the control specification varies, the control software needs to be rewritten to accommodate the new specification. Since PLC has high flexibility, one can update the current system while it is running thereby making easier implementation. In order to design flexible, reusable and maintainable control software, a good modeling tool is required. Petri nets are such a tool. Which facilitates analysis of behavioral properties, performance evaluation, and systematic construction of discrete event simulators and controllers. In this thesis a system with one robot and five sequential work …

Viscoelastic Effects On Parallel Flow Stability, Transition To Turbulence, And Turbulent Flow, Michael Garofalo

Theses

The classical two dimensional theory of stability of parallel flow is extended to viscoelastic fluids. How the elasticity of the fluid affects the point of stability and determines the point of transition to turbulence is analyzed. In addition the magnification of disturbances is elucidated. This study is based on a viscoelastic constitutive equation which has been successful in predicting the experimental trends of various unsteady high shear rate laminar flows. A viscoelastic stability equation which is an extension to the Orr-Sommerfeld equation for a Newtonian fluid is derived and solved for a flow between parallel plates superimposed by a two-dimensional …

Development Of An Expert System To Facilitate A Pump Manufacturing/Warehouse Facility, Muhammad Mutahir Ghauri

Theses

The objective of this study is to evaluate the effectiveness of utilizing an expert system technology as it relates to manufacturing. It appears that our industries are still uncertain about this technology. In the first phase of this study, procedure for deployment of this technology is discussed. Secondly a knowledge-based expert system is developed, using a VP-Expert microcomputer shell. The system is made of three modules, inventory module, cost analysis module, and decision making module (for the selection of pumps).

A warehouse was selected for the analysis, which carries the finished product in the form of pumps. The quantities and …

The Mobile Satellite Service (Mss) Systems For Global Personal Communications, Kiho Lee

Theses

A worldwide interest has arisen on personal communications via satellite systems. The recently proposed mobile satellite service(MSS) systems are categorized four areas: geostationary earth orbit(GEO) systems, medium earth orbit(MEO) systems, low earth orbit(LEO) systems, and highly elliptical orbit(HEO) systems. Most of the systems in each category are introduced and explained including some technical details. The communication links and orbital constellations of some systems are analyzed and compared with different categories, and with different systems. Some economical aspects of the systems are mentioned. The regulatory issues about frequency spectrum allocation, and the current technical trends in these systems are summarized.

Mechanical Behavior Of Polystyrene Foam Bead Lightweight Concrete, Hai-Ying Ni

Theses

This thesis is designed to investigate the effect of porosity on the mechanical properties (strength and modulus) of concrete, and to evaluate the effect of silica fume on the mechanical properties of the polystyrene foam bead lightweight concrete. In this research we made the lightweight concrete by using polystyrene foam beads as light weight aggregate and studied its mechanical properties in detail. Due to the near zero density and modulus of foam beads, we were able to consider it as "porosity". We could then control porosity in concrete by varying foam bead volume fraction.

In our experiments we used the …

Area And Perimeter Measurements Of Cells With Bound Fluorescent Antibodies, Aicha Weiss

Theses

The objective of this research was to geometrically analyze the characteristics of cells, specifically area and perimeter. The images were transferred from HP A900 system to an AVS work station. The images were visualized and manipulated by the AVS which permits the distinction between the cell body, fluorescent object, and background. The intrinsic geometry of the cell was determined by using image processing algorithms written in C. The images were then passed through a threshold filter, thereby yielding a black background and a white cell body. The perimeter calculation was then applied to the black and white images. Two test …

Case Study Of Assembly Defects In Manufactured Products, Michael J. Withka

Theses

Design for Quality Manufacturability (DFQM) is a design tool that empowers engineers to create designs that are easily and effectively transformed into manufactured products. The goal of this methodology is to make designers aware of design characteristics that may lead to product defects during the assembly process. Acknowledging the possibility of these defects will enable the designer to institute design modifications early in the design phase. The benefits realized in this approach are a reduction in the number of defects in the finished product, reduced product cycle times, a reduction in monitoring costs and a reduction in time-to-market.

This thesis …

A Systematic Approach To Defense Diversification, Sathappan Venkatachalam

Theses

The decline in defense spending has resulted in defense dependent companies seeking new markets through re-designing existing products, developing new products and restructuring their businesses. Defense diversification is defined as the process of transitioning a defense company's core capabilities (technologies, products, services) into commercial and non-Department of Defense government markets. A combination of site visits and review of the literature on defense diversification demonstrates the need for diversifying companies to adopt a systematic approach.

A concurrent new product development/product redevelopment model is proposed, based on the principles of concurrent engineering. The model consists of an eight phase development cycle and …

Scheduling Of Flexible Manufacturing Systems With Automated Guided Vehicles Using Petri Net Models, Hua-Sheng Chiu

Theses

In this thesis, Petri net models for Flexible Manufacturing Systems (EMS) are constructed. A firing sequence of the Petri net from the initial marking to the final marking can be seen as a schedule of the modeled FMS. By using the branch-and-bound algorithm, an optimal schedule of the FMS can be obtained.

Automated Guided Vehicle Systems (AGVS) are increasingly used for material handling in factories and warehouses. An AGVS can reduce labor costs and is ready to be integrated into an automated factory. This thesis presents two AGVS models (shared and duty) which integrate the control of AGVS with the …

Single-Axis Agonistic Motion Control System With Electro-Magnetic Actuators, Alexander Rokhvarg

Theses

A novel single-axis motion control system using solenoid electromagnet actuators is built and successfully controlled using a non-linear real-time control algorithm. Procedures for defining and modeling the electromagnetic actuator are established and implemented. Discrete-time nonlinear control law with global asymptotic stability and zero steady-state error is designed and numerically optimized. Stable operation with small-signal 0dB crossover frequency of 370 Rad/sec and positioning RMS steady-state error of better than 4 micron is achieved. Time domain parameters are verified on a working prototype. A step reference response positioning a 0.35 Kg mass payload over 1 cm travel in under 30 milliseconds is …

Synthesis Of Silicon Oxide/Vycor Composite Membrane Structures By An Optimized Lpcvd Process, Abhijit Datta

Theses

This study is focused on development of highly selective ceramic membrane structures consisting of silicon dioxide films synthesized by low pressure chemical vapor deposition (LPCVD) on mesoporous Vycor substrates. The ability of easily altering the composition of such films by varying the LPCVD processing parameters affords the opportunity of microengineering the pore structure by reducing the diameters of pre-existing pores in the support. The process parameters investigated include, deposition temperature, total pressure, and flow rate of oxygen. Both the kinetics and select properties of the deposits were examined. The growth rate as a function of temperature was seen to follow …

Simulation Of Activity Rhythms In The Hamster, Paul Qassis

Theses

In this research, an effort was made to better understand light-dark cycles which influence the physiological and psychological rhythms, circadian rhythms and their behavior. The research concentrated on mathematically modeling circadian rhythms (specifically hamsters' circadian activity rhythms) and establishing a physical correlation and creating a meaningful relationship between the mathematical model's parameters and the real biological oscillators which are responsible for these rhythms. The internal nature of the circadian rhythms is unclear. There is insufficient information and empirical data that describe them. Indirect means have to be employed for the description and exploration of such rhythms. Extensive real data analysis …

Electrical Power Dispatch To Motors Using Digital Modulating Techniques, David Michael Canny

Theses

The trend towards digital and microprocessor based control of power electronic converters has increased the level of research into digital modulating techniques. This thesis examines the inherent digital nature of Binary Rate Modulation with particular attention concentrated on its suitability for dispatching power to three-phase loads. The circuit topology of a three-level inverter is also examined and its performance aspects are compared with those of the more conventional two-level inverter.

Integral cycle Binary Rate Modulation is applied to an ac voltage controller and this method of power dispatch, which displays an optimal ac cycle positioning property, is compared with Pulse …

An Investigation Into Artificial Intelligence Based Generative Computer Process Planning, William Tereshkovich

Theses

The process planning function can be further optimized with the introduction of an intelligent software package such as an Artificial Intelligence based Generative Computer Process Planning System. An AI based CAPP system, also categorized as an expert system, provides the vital link between design and manufacture, a "bridge" of knowledge in the information chain of manufacturing engineering. With the increasing role of computers in the process planning function, planning has become easier, faster, and more efficient.

This thesis provides an explanation of the process planning function and how artificial intelligence will improve it. Topics in AI techniques and procedures, knowledge …

A General Method For The Inverse Kinematics Of Rotational Displacements In Spatial Mechanisms, John D. Kliminski

Theses

An iterative technique was developed to solve the inverse kinematics problem for the joint rotations in both closed-loop and open-loop spatial mechanisms and robotic manipulators in any prescribed configuration. The method is based on fixing one link in space and maneuvering the other links to form a closed chain, following an approximation of the actual physical assembly of the mechanism. In order to apply the same principle to both types of mechanisms, an open-loop mechanism was modeled as a closed-loop mechanism by creating a fictitious fixed link in the free space between the base and the end of the chain …

A Silicon Knife Design And Fabrication, Mingli Wang

Theses

In this thesis, the design and fabrication of a silicon knife is described. The device design is based on the principle of oxidation sharpening.

The knife is made from a silicon wafer and can be made to be any chosen length up to 150 mm. It was made with the same basic procedures used in semiconductor chip manufacturing. This type of processing/manufacturing results in a knife with a high degree of sharpness and smoothness compared with existing knife technology.

The knife fabrication plan combines IC processing, techniques including anisotropic and isotropic etching of silicon, plasma dry etching and chemical etching …

Characterization Of Sleep Eeg, Seetharamiah Sateesh

Theses

The physiological relationship between the various components of sleep and its variation due to drug administration has been used as one of the primary tools to analyze the performance of drug. A number of studies have been performed in recent years in this direction. Electroencephalogram (EEG) has been characterized with the help of variables ranging from measurements of the duration of different sleep stages to the activities that define the stages themselves. Advances in computer hardware and software have improved the methods of data acquisition and storage. Analysis of long stretch of data has always been a problem considering the …

Artificial Dielectrics : Characteristics At Low And Microwave Frequencies, Nitish Agrawal

Theses

Artificial Dielectrics have been characterized using transmission line and s- parameter measurements. The complex dielectric constant and loss of graphite filled and non-poled piezoelectric-aggregate (Polyvinylidene Fluoride, PVDF) filled plastic (PMMA) has been characterized at low (1kHz-10kHz range, i.e., the VLF, very low frequency, range) and microwave frequencies. The average diameter diameter of graphite particles used was thirty microns. Measurements were performed on very fine graphite (one micron diameter grains) and 30 micron sized grains for comparison purposes. Fine grain graphite particles exhibited a, larger real dielectric constant, probably owing to a larger dipole effect. The dielectric constant characterization has also …

A Gis Based Multi-Modal Multiple Optimal Path Transit Advanced Traveler Information System, Nicholas A. Koncz

Theses

A method for the design and use of a Transit Advanced Traveler Information System (TATIS) using an off-the-shelf Geographic Information System (GIS) is developed in this thesis. The research design included: 1) representing multi-modal transit networks in a digital form with schedule databases; 2) development of a multiple "optimal" path algorithm that takes into account walking transfers using published time schedules; 3) incorporating user preferences and penalties in the algorithm; 4) development of a user-interface with suitable output capabilities; 5) using the prototype for sample inquiries giving performance measures.

This prototype was developed using the Arc/Info GIS developed by ESRI, …

Building Oriented Surface Generation Through Iges Specification, Jujiang Bao

Theses

This thesis focuses the use of Initial Graphics Exchange Specification to generate automatically three dimensional surfaces. Currently, different CAD systems utilize their own data formats to generate graphic databases which are not compatible with one another. Besides, most of the existing CAD systems require an interactive data input process which is very much time consuming. In order to solve above problems, an efficient algorithm has been developed in this research to automatically generate portable graphic database following ICES specifications. This portable graphic database can be adopted by different commercial CAD/CAM systems. Using the proposed method, the current design process can …

Low Pressure Chemical Vapor Deposition Of Silicon Nitride Films From Ditertiarybutylsilane, Xiangqun Fan

Theses

In this study amorphous stoichiometric silicon nitride films were synthesized by low pressure chemical vapor deposition (LPCVD) using DTBS (ditertiarybutylsilane) and ammonia (NH₃). The growth kinetics were determined as a function of temperature in the range of 600-900 00, pressure in the range of 0.2-1.1 Torr, DTBS flow rate in the range of 10-50 sccm, and NH₃/DTBS flow ratio in the range of 5-20. At constant condition of pressure (0.5 Torr), DTBS flow rate (10sccm) and NH₃ flow rate (100 sccm), the deposition rate of as-deposited silicon nitride films was found to follow an Arrehnius …

Cad Study Of Linear Tapered Slot Antenna, Anthony W. Kwan

Theses

Linear Tapered Slot Antenna (LTSA) is an attractive candidate as a radiating element in frequency scanning arrays. LTSA element backed by a rectangular cavity had been investigated and is proven to posses various physical design parameters suitable to optimize its performance. This study is focused on the feed position variation to optimize the performance while maximum of the current density variation is maintained in the slot region. It was observed that if the stub base of the microstrip feed structure is located in the middle of the slot region, current maximum can be obtained within the slot region at the …

Adaptive Receivers For Direct-Spread And Multi-Carrier Code Division Multiple Access Systems, Xiangqun Liu

Theses

In this thesis, the detection of Direct Sequence Code Division Multiple Access (DS-CDMA) signals in an AWGN channel and Multi-Carrier (MC) CDMA signals in a time-dispersion channel is discussed.

The DS-CDMA receiver employs an adaptive multiuser interference canceler that utilizes deadzone limiters in the tentative decision stage. With weights adjusted adaptively, the prior knowledge of signal powers is unnecessary. The steady state error performance of this receiver is obtained and found to be superior to the performance of the same receiver using hard limiters for tentative decisions. The channel is considered non-fading in. this receiver.

Modeling the frequency selective channel …

Decentralized Optimal Control In Descriptor Systems, Hag-Yeon Park

Theses

Application of Matrix Minimum Principle to a linear decentralized optimal control in descriptor systems is studied in this thesis. Linear-quadratic index of performance with Gaussian initial state is considered. The necessary and sufficient conditions for optimality are derived

An additional constraint is imposed such that the controllers are linear function of output y(t) rather than of the state vector x(t). The optimal gain matrix G_i^* is then specified by the necessary conditions.

Two examples are developed to illustrate the concept.

Correlation Between Tidal Volume Measured By Spirometry And Impedance Pneumography, Krithika Seshadri

Theses

In this study, an alternative method, impedance pneumography was used to measure the respiration volume. The respiration volume was measured both by using a conventional spirometer and an impedance pneumograph, and evaluated quantitatively in 17 subjects using linear and nonlinear regression algorithms.

Data were collected from 17 normal, healthy subjects during rest and paced breathing conditions. A technique was developed to measure tidal volume by impedance pneumography. The respiration volume measured by the spirometer was correlated with the volume measured by the pneumograph. Different electrode positions and postures were included in the study to determine the position and posture which …

The Use And Evaluation Of Cleaner Wicks To Accelerate In Situ Bioremediation Of Organically Contaminated Groundwater And Soil, Brian Michael Sielski

Theses

The adaptation of Cleaner Wicks to accelerate in situ bioremediation of organically contaminated ground water and soil can be accomplished by making minor modifications to the Cleaner Wick design.

Once these changes in the Cleaner Wick design have been made the two primary ingredients necessary for aerobic microorganisms, nutrients and oxygen, can be delivered via the Cleaner Wick to the subsurface environment both above and below the water table to stimulate microbial growth and activity. Therefore, the microbial population will be able to biodegrade the target contaminants, rendering them harmless products such as carbon dioxide and water.

An adequate understanding …

A Distributed Network Architecture For Video-On-Demand, Ge Dai

Theses

The objective of this thesis is to design a distributed network architecture that provides video - on - demand services to public subscribers. This architecture is proposed as an alternative to a centralized video service system. The latter system is currently being developed by Oracle Corporation and NCube Corporation.

A simulator is developed to compare the performance of both the distributed and centralized video server architectures. Moreover, an estimate of the cost of both systems is derived using current price data.

It is shown that the distributed video server architecture offers a better cost / performance trade-off than the centralized …

Computerized Scoring Of Sleep Stage Data, Subbarao Narayana

Theses

Sleep is a non-uniform biological state which has been subdivided into different stages. The basic criteria behind staging are the amplitude and frequency variations of sleep data. The sleep analysis is carried out by considering the characteristic variation of all three EEG, EOG and EMG signals. The polygraphic recording of nocturnal sleep is a method of research widely used in neurophysiology laboratories, both for the clinical study of sleep and for the evaluation of the therapeutic effectiveness of drugs acting on sleep. The analysis of this method is carried out by an expert individual whose depth of knowledge regarding the …