Engineering Commons^™

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 …

Autonomic Nervous System Evaluation Using Time-Frequency Analysis, Sanjay Fernando

Theses

Spectral analysis of heartrate variability (HRV) provided an estimate of the sympathetic and parasympatheticinfluences on heart rate without drugs or other invasive procedures.However, there are many situations where heart rate changed rapidlyover time and the control of those changes was of considerable interest.Time-frequency analysis was utilized to expand the concept of spectralanalysis of HRV to describe changes in vagal tone and sympatho-vagalbalance as a function of time. As a result the assessment of the autonomicnervous system during rapid changes in heart rate was made.

There were three advantagesto calculating vagal tone and sympatho-vagal balance by using timefrequencyanalysis. First, vagal tone …

Cebus Demonstration System, Liang-Chuang Chen

Theses

A CEBus demonstration system is constructed and applied to aspects of home automation security. Two M68HC16Z1 evaluation boards are used as CEBus nodes. Two CEBus spread spectrum power line modems (SSC PLCEMS) interconnect the nodes. An SSC PLCEMS handles all spread spectrum signal generation and reception.

The application programs in the two boards are written in assembly language based upon CAL (Common Application Language), a CEBus standard.

The standard CEBus frame format and FCS (Frame Check Sequence) are implemented by software in the Data Link Layer. Encoding and decoding binary information into UST format are implemented in the Physical Layer. …

Processor Allocation For Partitionable Multiprocessor Systems, Nicholaos C. Antoniou

Theses

The processor allocation problem in an n-dimensional hypercube multipro-cessor is similar to the conventional memory allocation problem. The main objective is to maximize the utilization of available resources as well as minimize the inherent system fragmentation. In this thesis, a new processor allocation strategy is proposed, and compared with the existing strategies, such as, the Buddy strategy, the Single Gray Code strategy (SGC), the Multiple Gray Code (MGC), and the Maximal Set of Subcubes (MSS). We will show that our proposed processor allocation strategy outperforms the existing strategies, by having the advantage of being able to allocate unused processors to …

An Adaptive Correlator Receiver For Combined Suppression Of Co-Channel Interference And Narrow-Band Jammers In A Slowly Fading Channel, Raymond Carbone

Theses

This work deals with the adaptive correlation of a direct sequence spread spectrum signal in the presence of narrow-band, multipath and multiple user interference. The Least Mean Square and Recursive Least Square algorithms are employed for the adaptive convergence of the correlator receiver to minimize the mean squared error.

The performance of the adaptive correlator is compared with the matched filter correlator receiver and the conventional prediction filter for the suppression of narrow-band interference by calculating the bit error probability rate. The adaptive correlator is also compared with the RAKE receiver for multipath suppression and compared to the decorelating detector …

Passive Radiosonde Transducer Design For Remote Pressure Sensing Applications, Yang Gao

Theses

Intracranial pressure can be measured to accuracies within 1 milliTorr using passive microtransponders that are micromachined using silicon as a base technology. These microtransponders can operate with either a dual-oscillator or a phase-locked loop frequency scanned control system.

The current work describes the design of a totally implantable microsensor for biomedical applications with the aim to monitor and measure the epidural intracranial pressure . The implanting microsensor is basically an RLC device in which capacitance varies with fluid pressure. The resonant frequency of RLC Series connected device varies with chemically etched diaphragm electrode spacing and thereby measures the variations with …

Control Of Smart Structure Using Adaptive Dither, Tian Hong

Theses

In this thesis, a mathematical model of a piezoelectric stack actuator is presented to describe its voltage versus displacement hysteresis characteristices. This model can accommodate a wide range of piezoelectric materials, including the PZT (lead zirconate-lead titanate) type which is most popular in industrial applications.

Besides describing the conventional "single-loop" hysteresis, this model also accounts for the off-axis minor loops by augmenting the algorithm with loop indexing.

It is shown that the PZT hysteresis possesses certain "weak scalability" that enables the use of spectral analysis to measure the level of nonlinearity.

After a suitable mathematical model has been obtained, a …

Influences Of Cardiac And Respiratory Parameters On Heart Rate Variability, Melissa Leifer

Theses

Heart rate variability is a result of variation in the activity of the sympathetic and parasympathetic nervous systems. Methods have been developed to determine the level of parasympathetic activity by observing the heart rate variability spectrum. Most of the previously published research uses only level of parasympathetic activity and respiratory rate to draw conclusions about the interactions of the autonomic nervous system with physiological parameters. In order to gain a complete understanding of the autonomic nervous system and the mechanisms responsible for heart rate variability, respiratory volume, cardiac variables and pulmonary variables need to be considered. In addition, amount of …

Data Broadcasting And Reduction, Prefix Computation, And Sorting On Reduced Hypercube (Rh) Parallel Computers, Arup Mukherjee

Theses

The binary hypercube parallel computer has been very popular due to its rich interconnection structure and small average internode distance which allow the efficient embedding of frequently used topologies. Communication patterns of many parallel algorithms also match the hypercube topology. The hypercube has high VLSI complexity. however. due to the logarithmic increase in the number of connections to each node with the increase in the number of dimensions of the hypercube. The reduced hypercube (RH) interconnection network. which is obtained by a uniform reduction in the number of links for each hypercube node. yields lower-complexity interconnection networks when compared to …

Integration Of Surfactants And Time Release Nutrients With Pneumatic Fracturing Process, Atiqur Md. Rahman

Theses

The objective of this laboratory study was the development of two novel improvements to the pneumatic fracturing process which would extend its present application. The first involved use of surfactant during pneumatic injection, and the second was subsurface injection of "time-release" dry nutrient pellets for enhancement of in situ biodegradation.

Bench scale tests demonstrated that pneumatic fracturing can be successfully performed with air containing a surfactant solution (foam fracturing). The results showed that foam fracturing followed by increased the rate of surrogate contaminant removal from 8% to 10% compared with regular pneumatic fracturing. These increases were attributed to enlarged fracture …

The Influence Of Hydrodynamics And Particle Size On The Rejection Properties Of Ultrafiltration Membranes, Usama M. Shahin

Theses

A mathematical model based on the flow hydrodynamics is developed to calculate the treatment efficiency of ultrafiltration process. This model relates the treatment efficiency with the consideration of both fixed parameters and variable parameters. The fixed parameters are function of the intrinsic rejection coefficient, diffusion coefficient, and viscosity whereas the variable parameters can be related to the fluid velocity, volume flux, and cartridge dimensions. The model has been examined by solutions with solutes that have different molecular weights. The experimental data fits the proposed mathematical model very closely suggesting its suitability to evaluate the rejection efficiency in ultrafiltration. As such …

Artificial Dielectric Materials : Synthesis And Optical Characterization Of Small Metal Clusters Embedded In Polymeric Matrix, Nazneen Karim Shilpee

Theses

This study is concerned with the fabrication of films made of gold, nickel, and silicon clusters dispersed in a polymeric matrix. The films were fabricated by use of metal or semiconductor sputtering and plasma polymerization of Methyl Methacrylate monomer in a capacitively coupled RF (13.56 MHz) sputtering system. Optical transmittance and optical reflectance were measured as a function of wavelength. The optical absorption of metal or silicon clusters was studied as a function of cluster size. Cluster size and content were determined from Transmission Electron Micrographs (TEM). The absorption band resulting from a plasma resonance in the clusters was found …

Cervical Spine Bone Anchoring System Csbas Pullout Testing And Comparisons, Konstantin Caploon

Theses

The purpose of this study is to prove the effectiveness of the newly designed and patented Cervical Spine Bone Anchoring System (CSBAS). It is a posterior fixation device intended to be used with spine bone-plate systems. Its purposes are to substitute for conventional bone screws, significantly decrease the neurological and vascular risks associated with screws, and have comparable bone purchase strength.

Three CSBAS sizes (10mm, 12mm, and 14mm) were compared to four conventional bone screws in six human cadaveric cervical spines (C2-C7). Post-implantation axial pullout tests of each device using an MTS servohydraulic testing machine yielded bone purchase strength.

In …

Behavior Of Concrete And Slender Reinforced Concrete Columns Under Cyclic Axial Compression With Bidirectional Eccentricities, Byong Youl Bahn

Dissertations

A rational analysis of reinforced concrete (R/C) structures requires satisfactory modeling of the behavior of concrete under general loading patterns. The behavioral characteristics of concrete dominantly depends upon its load history. For the study of concrete behavior, parametric study and experimental investigation into the behavior of concrete under load history of random cycles are performed. Through parametric study, the applicability of the previous concrete models is examined and a physically motivated modeling for the cyclic stress-strain relationships is proposed. The present modeling of concrete under general cyclic loading is initiated to provide substantial applicability, flexibility of mathematical expressions and furthermore …

Theoretical Evaluation Of The Break Off Test For Concrete, Arjuna Priyara Ranasinghe

Dissertations

Strength of concrete is normally measured using the standard cylinder or cube. The measured strength is used for design. The accuracy of concrete strength is frequently challenged, particularly in large concrete structures where size effect of the test specimens is attributed for the differences. Many nondestructive tests were developed to evaluate concrete strengths. In recent years, it was obvious that these tests are unreliable. As the infrastructure decays, more nondestructive tests are required to evaluate the existing structures.

The Break Off Test is a recently developed nondestructive test. Although substantial amount of experimental investigations have been carried out on this …

Particle Dynamics Modeling Of Vibrating Granular Beds, Yidan Lan

Dissertations

Particle dynamics modeling is done to study the behavior of granular beds subjected to vibrations imposed by a plane boundary which oscillates sinusoidally about a zero mean speed. Significant differences between the lower and higher shaking acceleration regions are found for the granular temperature and solids fraction depth profiles, which characterize the effectiveness of the boundary in fluidizing the beds. When higher accelerations are applied, the temperature is maximum at the vibrating floor and attenuates through the depth, while the solids fraction profiles exhibit a maximum at some intermediate depth. At lower acceleration values, most of the mass is located …

Oxidation Of Pollutants In A Batch Recirculation Bioreactor With Immobilized Microorganisms, Jongtai Jung

Dissertations

The purpose of this work was to study bio-oxidative destruction of several substrates in an immobilized cell batch bioreactor in recirculation configuration. This system was used in three cases: a series of substrates usually used as monomers, ethylene glycol and its tetramer, and phenol under magnetic irradiation. In addition, kinetic studies were performed and experimental versus predicted results compared.

The substances styrene, methyl methacrylate (MMA), and β-hydroxybutyric acid (HBA), common monomers, were biologically treated using an acclimated mixed microbial community immobilized in calcium alginate gel. A comparison of biodegradation rates (3.3, 9.4, and 15 ppm/hr for styrene, MMA, and HBA, …

Motion Estimation Using Optical Flow Field, Jingning Pan

Dissertations

Over the last decade, many low-level vision algorithms have been devised for extracting depth from intensity images. Most of them are based on motion of the rigid observer. Translation and rotation are constants with respect to space coordinates. When multi-objects move and/or the objects change shape, the algorithms cannot be used.

In this dissertation, we develop a new robust framework for the determination of dense 3-D position and motion fields from a stereo image sequence. The framework is based on unified optical flow field (UOFF). In the UOFF approach, a four frame mode is used to compute six dense 3-D …

Adaptive Nonlinear Control Using Fuzzy Logic And Neural Networks, Shu-Chieh Chang

Dissertations

The problem of adaptive nonlinear control, i.e. the control of nonlinear dynamic systems with unknown parameters, is considered. Current techniques usually assume that either the control system is linearizable or the type of nonlinearity is known. This results in poor control quality for many practical problems. Moreover, the control system design becomes too complex for a practicing engineer. The objective of this thesis is to provide a practical, systematic approach for solving the problem of identification and control of nonlinear systems with unknown parameters, when the explicit linear parametrization is either unknown or impossible.

Fuzzy logic (FL) and neural networks …

Removal Of Vapors From Air By Selective Membrane Processes, Junseok Cha

Dissertations

The behaviors of different membrane modules for the selective removal and recovery of water vapor and some volatile organic compounds (VOCs) from N₂ have been studied. For the selective permeation-based removal of water vapor from N₂, a polymeric water-swollen gel membrane in the form of Cuprophan hollow fiber was employed. A thin film composite type rubbery membrane module was studied for the selective removal of VOCs like toluene or methanol from N₂ by permeation. The usefulness of pore-condensation phenomenon-based removal of toluene or xylene from N₂ was explored using a microporous ceramic tubular membrane.

The …