Digital Commons Network^™

Effective Techniques For Selection Of Information Systems Personnel, Robert Reginald Downs

Theses

Although major developments in information systems have occurred within the last two decades, staffing to manage these systems has received limited attention. Staffing information systems personnel is investigated in this study to develop effective techniques that can be used in the selection process.

Recent literature on selection and staffing has been reviewed to establish methods that can be used to identify qualified candidates. Technological developments and the resulting effects upon organizational operations are examined, revealing the transition in the information systems management function as well as the effects upon the role of these personnel. The qualifications that are associated with …

Stepping Motor Control And Position Monitoring, Pei-Kuan Feng

Theses

Stepping motors provide precise digital control of speed, without speed detector feedback. A stepping motor can produce a large torque for a relatively small displacement, without a shaft-position sensor or special compensation. This provides accurate control of motor position. This thesis describes the development of stepping motor torque characteristics and the different approaches stepping motor phase current waveform detection. It is shown that one of the most useful indicators of rotor position is the initial rate of current rise. The Hybrid, Permanent-magnet and Variable-reluctance step motors have been applied in the drive circuits. The open-loop control circuits are implemented to …

The Tapered Dielectric Rod-Conical Antenna, Nicholas I. Georghiades

Theses

The problem of the linearly tapered dielectric rod/conical antenna, excited by the HEI1 hybrid mode in a metallic circular waveguide , is rigorously studied. A theoretical model, and numerical investigation for the radiation characteristics of such an antenna are presented. The model is based on the combination of classical analysis of the Electromagnetic Fields within the dielectric rod, Local Mode Theory, and the Equivalence Principle for the determination of equivalent current distributions.

The far-zone radiation field is considered to be the summation of the fields produced by two radiative components in the dielectric rod/conical structure: The "aperture" of the uniform …

Microcomputer-Controlled Respiratory Rate Monitor, David John Hartmann

Theses

In order to measure the metabolic change in an animal due to the administration of anti-obesity drugs, an instrument was constructed which will allow the continuous sampling of twelve individual animals residing in enclosed chambers. The instrument is based on the principle of Indirect Calorimetry, which measures metabolic rate by sampling the inlet and outlet concentrations of respiratory gases (oxygen and carbon dioxide) of the chamber. The system is controlled by an IBM PC which will control six chambers or twelve chambers simultaneously.

The system assesses the metabolic rate of the animal by calculating the Respiratory Quotient (RQ) and the …

A Computer-Based Microwave Interferometer Instrumentation System As A Non-Invasive Cardiopulmonary Monitor, Chin-Yee Eric Ho

Theses

The system comprises a microwave interferometer as a computer-based non-invasive cardiopulmonary monitor. The microwave interferometer records the mechanical vibration of the chest wall. The objective is to determine whether the signals may have diagnostic value and to evaluate the instrument as a non-invasive and non-contacting cardiopulmonary monitor.

With the help of a computer it is possible to analyze the mechanical vibration of the chest wall produced by the heart and thereby detect, and possibly categorize, cardiac abnormalities. This system is able to process two channels, the first signal from microwave interferometer records chest wall vibrations and the second signal is …

Role Of Contact Stresses In Surface Fatigue And Wear, Chih-Chi Huang

Theses

This thesis is devoted to the role and analysis of stress distribution at the area of load and slide contact in the surface fatigue. The orthogonal shear stresses are critical stresses for surface fatigue in pure rolling contact. On sliding combination with rolling, the maximum shear stresses become to be the prime cause for surface fatigue because they move from subsurface toward the surface. The compressive residual stress induced during manufacturing could increase the resistance to surface fatigue. Sliding speed rarely affects the stress distribution and surface fatigue. From investigation of the stick-slip region in the contact area, sliding wear …

Reliability Of Packaging In Microcircuits, Zia Iqbal

Theses

The semiconductor industry is faced with the problems of how to increase the level of reliability of semiconductor parts being used in the electronic systems which have had their lifetimes extended through new and better system design.

This paper deals with the reliability of packaging constructions commonly used in large scale integration / integrated circuits and will present the failure mechanisms and failure modes which can arise when proper processing is used. In addition, the materials used in each construction and how they affect reliabilty will be analyzed.

It is not the intention of this paper to present any new, …

Determination Of Project Duration For Resource Constrained Projects Without Using Resource Scheduling Procedure, Rabindra Nath Karmakar

Theses

The problem addressed in this thesis is that of determining the practicability of equating measures of network and resource characteristics to the early finish date of a project which is constrained by resources. The output of standard critical path calculations along with information on resource profiles that are easy to calculate can be of use in estimating resource constrained project duration.

Twenty two different equations ( developed by Hall) were used to find the estimated project finish dates. These results were compared to the schedule resulting from the application of the heuristic rule of minimum activity float. It is shown …

Schema Based Wiring Tool : A Computer Network And Cad Design System, Jia Jing Zhang

Theses

For the purpose of building a SBC-8052-Basic micro-controller based instrument system, a new SCHEMA II Computer Aided Design system for IBM-PC is used to enhance circuits design routine, and it is described here. The new features of this CAD are discussed, and the design example of a new version of the SBC-8052-Basic micro-controller is given here in detail.

Since the wiring board system is adopted as tool of the laboratory development and controlled by the QL microcomputer, and since SCHEMA II CAD, on the other hand, is used on the IBM-PC-AT, communication between the two microcomputers is accomplished, and the …

Softening Response Of Concrete In Direct Tension, Teresa Cintora

Theses

Due to the increased attention in nonlinear fracture mechanics and numerical methods of cementitious material, it has become necessary to have a reliable investigation of the post-peak softening response of concrete under direct uniaxial loading. But due to the brittleness of the material previous researchers have encountered great difficulty in obtaining complete data regarding the load-deformation behavior. This study uses a strain-controlled testing method and therefore the post-peak curve can be more easily obtained. Based on these results a unique formula for the normalized load vs. deformation curve has been proposed to be applied in fracture analysis applications.

Microbial Phenol Degradation Utilizing A Complete-Mix Biological Reactor : The Effects Of Dissolved Oxygen Content, Keith Kollar

Theses

Experiments were conducted using phenol as a sole carbon source in a series of completely mixed biological reactors with solids recycle (CMBR). The reactor working volume was 4 liters, and solids were recycled from 3 liter clarifiers. Dissolved oxygen concentration (DO) was varied in order to determine the impact of this important variable on system operability.

Phenol was removed at better than 99 percent efficiency during most of the runs. Filamentous growth was not observed during any run. However, bulking did occur at higher DO levels, which was the result of microbial slime production.

Study Of The Structure And Capacity Of Construction Industry In Pakistan, Tayyab A. Ansari

Theses

The construction industry is the second largest sector in Pakistan's economy after agriculture. It is a fragmented industry which includes very small and very large contracting groups. It includes professional groups such as architects, engineers, management personnel etc. Major part of this industry is dominated by material's suppliers, vendors etc.

In the light of the developments which have taken place particularly over the last ten years, the study has covered the capacity of the construction industry in terms of estimated output, availability of manpower, demand and production of building materials , financial problems, credit, quality of work, the role of …

Pentachlorophenol And Oxygen Consumption Of Immobilized Mixed Bacterial Culture, Tesfamariam Stephanos Tsadwa

Theses

This study was undertaken to investigate the effects of Pentachlorophenol (PCP) concentration on oxygen consumption of immobilized microbial cells. The microbial population, from a municipal wastewater treatment plant, was immobilized in calcium alginate gel. The following studies have also been conducted in this project:

1. Comparison of the effect of PCP concentration on oxygen uptake between immobilized and free cells.
2. Comparison of the effects of PCP concentration on oxygen uptake between acclimated and an unacclimated bacterial beads.

Dissolved oxygen concentration was monitored using a flow Clark-type oxygen probe, in a micro-assay bioreactor. It was found that PCP concentrations higher than 2000ppm …

A New Hazardous Waste Treatment Technology Utilizing Low Power Density Microwave Energy, Gabriele Else Windgasse

Theses

Two major applications of a new hazardous waste treatment technology using low power density microwave energy have been characterized: 1) Desorption of organic materials such as: trichloro-ethylene, para-xylene, naphthalene and gasoline hydrocarbons from substrates such as: sand and granulated activated carbon was achieved by microwave induced steam distillation and the application of a new phenomenon: arcing between GAC particles when they are exposed to microwave radiation. All contaminants could be removed to 100% (non-detectable with GC and GC-MS). 2) Decomposition of organic contaminants such as: trichloro-ethylene and trichloro-ethane in arcing/heating GAC beds. A new fluidized bed reactor ("RDW-reactor", after Ray, …

Adsorption And Kinetics Of Adsorption By Flyash In Solution, Murthy K. Jogimahanti

Theses

The phenomena of adsorption is extremely important in water/wastewater treatment process. A process which uses flyash as the sorbent for removing organic compounds from aqueous solutions has been investigated. Also, the rate at which this process occurs, i.e., the kinetics of adsorption, has been studied. Single solute systems were examined and the samples were analyzed using a Flame Ionization Detector Gas Chromatograph. The potentialities of adsorption on flyash as a method of renovation of water have not been realized fully, because little knowledge is available regarding the effective application of the method for this purpose.

Flyash has been known to …

A Silicon Photodiode Array For Soft X-Ray Sensing, Chih-Te Hu

Theses

An array of 30 x 30 sensing cells including logic within each cell and a self-scan address circuit are described. A unique scintillation technique is used to increase the threshold sensitivity 60dB for X-ray photon sensing beyond that obtainable with conventional photodiode sensors. Simulations for the sensing cell and some additional logic elements are based on SPICE version 2G5 and HILO 3. Worst case analysis includes variations in threshold voltage V_TP and V_TN for the CMOS circuit components. The final CMOS chip dimension using MOSIS 1.2 micron rules is 10mm x 10mm base on the 80 …

Sorptive And Geotechnical Characteristics Of Kaolinite, Chi-Yuan Shih

Theses

The sorption/desorption behavior of phenol and chlorobenzene as well as their influence on geotechnical characteristics of kaolinite were studied. The results reveal that the sorption process follows closely with the Freundlich adsorption isotherm whereas the sorption/desorption ratio depends upon the characteristics of organic compounds.

A series of geotechnical properties tests was also undertaken after achieving equilibrium at different concentrations of organic compounds. It was found that the parameters such as liquid limit, plastic limit, optimum moisture content, and dry density increase with an increasing-concentration of organic compounds.

The relationship between the geotechnical, properties and sorption behavior of soils provides the …

Investigation Of Different Cmos Dram Sense Amplifier Configurations In Vlsi, Bihju Chiu

Theses

Sense amplifiers are particularly difficult circuits to design. In this work, only CMOS sense amplifiers are considered. There are typically two configurations of CMOS sense amplifiers: the cross-connected flip flop configuration and the current-mirror configuration. They are widely used nowadays with various modifications. These improved configurations are simulated and optimized with SPICE package, and their relative performances are also compared in this thesis.

Determination Of Polycyclic Aromatic Hydrocarbons From Incineration Emission Samples, Robert Cebula

Theses

Stack emissions from five sources (one pulverized coal combustion operation, three sewage sludge incineration operations and one gray tin refractory operation) were sampled by use of U.S. EPA Modified Method 5 isokinetic sampling unit for vapor and particulate effluent. The sampling unit provided XAD-2 resin samples, polytetrafluoroethylene and glass fiber filters and impinger washings of dichloromethane. The resins were soxhlet extracted using dichloromethane (DCM) and the filters were soxhlet extracted using DCM followed by acetone. Fractionation of extracts was accomplished by thin layer chromatography. The resulting fractions were analyzed for polycyclic aromatic hydrocarbons (PAH), nitro-PAH and quinone-PAH by high-performance liquid …

An Investigation Of Electrical And Optical Properties Of Reactively Sputtered Silicon Nitride And Amorphous Hydrogenated Silicon Thin Films, Tae Hoon Kim

Theses

Thin films of silicon nitride and amorphous hydrogenated silicon were prepared by radio frequency reactive sputter deposition and their properties optimized for their use as low temperature passivation coatings for optoelectronic devices. The effect of various sputter deposition parameters on the conduction and optical properties were studied. Infrared spectrophotometry and ellipsometry were used to determined the optical properties of the films whereas the electrical properties were determined from current-voltage measurements of MIS capacitors.

Typical parameters of a sputter deposition run for the best Si₃N₄ films were: base pressure, 1-2x10^-6 torr; sputtering pressure, 5 mtorr; nitrogen partial …

A Model For The Determination Of Market Based Pricing Of Telecommunication Products, Katherine J. Sullivan

Theses

The deregulation of AT&T, has impacted telecommunication product pricing in the U.S. market. Previously, pricing had been based on cost plus mark-up, as stipulated by regulatory commissions. Now, pricing decisions require consideration of the competitive impact, consumer demand for the product, corporate pricing objectives and marketing strategies. This paper proposes a pricing process that is relevant for this new environment which enables the product manager to price properly.

The method proposed utilizes microeconomic theory and takes into account the product test price, unit cost, opportunity cost, nonprice factor cost and consumer demand. Incorporating a number of different pricing strategies, it …

Bead Design For Biodegradation Of 2-Chlorophenol Using Microorganisms Entrapped In Alginate Gel, Fayaz Lakhwala

Theses

The performance of immobilized cell reactors varies with a number of parameters, one of which is proper bead design. A mixed microbial population from a waste water treatment plant was immobilized in calcium alginate gel. The viability of these organisms was studied in a microassay reactor by varying parameters such as concentration of calcium chloride, concentration of sodium alginate, temperature of operation, biomass concentration within the beads and concentration of a model compound (2-chlorophenol). The effect of storage on viability over a period of three months was also investigated. It was found possible to have access to active biomass by …

Use Of Recirculation Reactor To Study Biodegradation Of Aroclor 1242, A Polychlorinated Biphenyl, Babu S. Sanji

Theses

The performance of immobilized microorganisms in the detoxification of hazardous waste was investigated using a recirculation flow reactor, run in a batch mode. A mixed microbial population from a wastewater treatment plant was immobilized in calcium alginate gel. The bio-oxidation ability of these microbes towards a model toxin Aroclor 1242 (R) (PCB 1242) was studied.

A non-ionic surfactant (Triton X-405 (R)) was used as a medium in the enhancement of the solubility of Aroclor 1242 in aqueous phase.

Dissolved oxygen concentration was monitored using a flow Clark-type dissolved oxygen probe. Oxygen consumption was compared to the biodegradation of Aroclor 1242. …

Design Of A Fiber Optic Oxygen Sensor Based On Immobilized Hemoglobin, Mendu Govind Raj

Theses

The fiber optic Oxygen sensor consists of a thin layer of immobilized deoxyhemoglobin at the common end of a bifurcated fiber. Immobilization is done using the alginate gel procedure. The immobilized reagent is separated from the standard oxygen sample by the gel with or without semi-permeable membrane, and the entire configuration is enclosed in an oxygen free sample cell. Light from a tungsten-halogen lamp, filtered through a 405nm filter is passed through one arm of a bifurcated fiber to the sample cell. The reflected intensity (a highly polished aluminum foil or a plate is placed at the bottom of the …

Investigation Of Forces In The Course Of The Water Jet--Work Piece Interaction, Hung-Yuan Li

Theses

This study is concerned with the dynamic of the interaction between the water jet and the work-piece. The piezoelectric transducer was used to construct an experimental setup. The simultaneous use of the constructed setup and strain gage enables us to validate the experimental procedure. The forces in the impingment zone were measured at different operational conditions. Totally about 400 different combinations of these conditions were tested. It was found that the force is mainly determined by the diameter of the sapphire. The effects of the abrasive size , abrasive flow rate, the diameter of the carbide tube, and the stand-off …

Synergistic Fillers In Polymer Concrete : New Composites, Syed Hassan Javed

Theses

The objective of this study was to examine the effects of synergistic fillers on underwater construction, burning and mechanical properties of polymer portland cement concrete(PPCC).

Fine grains of hydrous calcium sulfate, Trihydrated alumina, Calcium carbonate and fibrous unhydrous calcium sulfate were examined in PPCC. It has been observed that these synergistic filler improves the mechanical property (stress) and reduce the average time of burning of PPCC. With fixed quantity of polymer, the deterioration of PPCC in water increases by replacing the sand with above stated fillers.

Comparison Of Various Techniques For The Detection Of Lines In 2-Dimensional Images, Somayajulu Bhamidipati

Theses

The detection of straight lines in 2-dimensional images leading to polygonal approximation to the boundaries of the objects is one of the important stages in scene analysis as it leads to the description of the images. The comparison of three diverse approaches for this problem in terms of the efficiency and accuracy is made, and their performance for different types of data and different sets of parameters is studied in this thesis.

The data points are generated using either an edge detection algorithm using chain encoding on real images or a synthetic data generator, which can create a variety of …

Data Flow Dependency Generator, Chin-Piao Chan

Theses

Data flow is a new approach to parallel computing. The concept is to enable the execution of an instruction whenever its operands become available. The only constraints in a data flow machine are the data flow dependencies between instructions.

In this thesis, a simulation package called the Data Flow Dependency Generator is developed. This package is designed to express the idea of data flow computations, the data flow dependencies and the use of multiprocessors.

Given a number of processors, a number of time units for each operation and a program, the Data Flow Dependency Generator finds the data dependencies between …

Utilization Of The Theory Of Constraints Approach For Improving A Manufacturing Enterprise Profitability : A Case Study, Yaron Chaut

Theses

The past two decades have been a difficult period for the U.S. as it lost its dominant position in one manufacturing industry after another to Japan. The American worker was initially blamed for this phenomenon - he was too expensive, was less productive, and produced lower quality products then the Japanese worker. The opening of factories in the U.S. managed by Japanese with American workers proved this claim to be wrong, as their products were competitive and often even better then the original Japanese products. It also indicated that the Japanese production planning and control methods are the primary reason …

Expert Systems Approach For Means Of Egress Analysis, Dimitrios N. Dontas

Theses

The use of Expert Systems has grown dramatically during the 1980's. Developed as a branch of Artificial intelligence, knowledge based Expert Systems were at first of academic interest only. With successful application of knowledge based Expert Systems to medical and other diagnostic problems, industrial and commercial use of this technique is also increasing significantly. As of 1986, fifty percent of the Fortune 500 companies are embarked in their own Expert Systems research.

A variety of knowledge based Expert Systems has been developed for the Civil Engineering design and construction industries. The applications cover a wide range of subjects, including among …