Digital Commons Network^™

Pwm Motor Control: Model And Servo Analysis, Rick J. Sandor

Theses

In recent years, the performance requirements of high power servo motor systems utilizing pulse width modulated (PWM) switching amplifiers have steadily increased. These PWM motor amplifiers perform an important function in the d.c. servo system by boosting the low level command signal to the high voltage and current levels required by the motor. Ideally, this power gain is to be constant over all input frequencies but, in reality, gain is frequency dependent which affects system dynamics. The amplifier gain and phase versus frequency relationships an*i amplifier noise and d.c. offsets which may affect system response must be known to the …

A Stability Test Of Dry Silver Microfilm, Christopher Edwards

Theses

A research project has been completed, in which experiments involving temperature and humidity were performed on 3M experimental microfilm samples. The experiments dealt with humidity levels usual to file storage conditions and elevated temperatures to allow for accelerated aging studies. Arrhenius plots were used to extrapolate the results obtained to normal room temperatures. The data obtained indicated that the film has a life expectancy of 62 years at 30% relative humidity and 53 years at 50% when stored at 24 C.

Frequency Filtering Characteristics Of The Halftone Contact Screening System, Rudolph J. Guttosch

Theses

A simplified model of the halftone contact screening system was devised and tested to determine the applicability of the model for predicting frequency transfer characteristics of the system. The model was tested using illuminance sinusoids of varying frequency as input to the halftone system. The output was obtained by optically correlating the exposing sine wave with its halftone image. It was found that the halftone system is capable of transfering information at frequencies greater than the screen frequency, and that the model generally underestimates the ability of the system to reproduce high frequency information, although the basic shape of the …

Analysis Of Deflection Temperature Under Load, Anand M. Jagani

Theses

Deflection Temperature Under Load (DTUL) is an experimental value commonly used by designers to characterize a plastic in a high temperature environment. This value is currently measured by a standard test procedure specified by the ASTM D-648. A theoretical analysis of this test was made and computer programs were developed to calculate the Deflection Temperaure of Plastics Under Load based upon temperature dependent flexural modulus data and temperature dependent thermal properties of the plastics of interest. The results obtained from the theoretical analysis agree closely with the experimental values found in the literature for two resins. An analysis of the …

An Inquiry Into Engineering Career Choice And Career Satisfaction, Gunars Bachs

Theses

The purpose of this thesis was to ascertain factors that motivate a person to study engineering, and to examine the aspects of engineering career satisfaction. This study was conducted as a survey by means of a mail questionnaire, which was distributed among graduates of New Jersey Institute of Technology. Another sample, comprised of master's degree recipients of NJIT who had received their bachelor's degree from other undergraduate schools, served as a control group.

Motivation factors and positive and negative aspects of the engineering career were established and ranked in order of their importance. A method to measure career satisfaction was …

An Investigation Of The Effects Of Required Homework Versus No-Homework On The Achievement Level Of Third Graders In Mathematics And Language, Dorothy L. Winton

Theses

Purposes of the Study: The purposes of this study were to examine the effects of two types of homework on the achievement level .of third graders in language and mathematics. Specifically, the study was designed to answer the question: Is there a significant difference in the achievement of students who have homework and those who do not have homework? Does the subject matter make a difference?

Procedures: In this study, twenty students from one classroom were randomly placed into two experimental groups of ten students each. Each experimental group was used as a control group for the other.

Both groups …

Peer Tutoring: A Systematic Approach To Individualizing Instruction For Academic Gains, Dorothy Payne

Theses

Can peer tutoring significantly improve student achievement, comparing students who received peer tutoring and students without peer tutoring? The purpose of this investigation was to determine whether peer tutoring, systematically controlled, could significantly improve student achievement, comparing students who received peer tutoring and students without peer tutoring.

The major research hypothesis is: There will be a significant difference between the mean gain scores of the experimental and control groups in counting money, telling time, and linear measurement as a result of the treatment from a systematic peer tutoring program.

The sample for the study consisted of 16 second grade students …

The American Manager In Saudi Arabia, Sharif F. Luwe

Theses

This study was designed to investigate the managerial environment, attitude, and experience of the American employees who were involved in the American multi national corporation which operates in the Saudi Arabia . Due to the multicultural nature of t his kind of global business setting many problems were generated because of cultural differences in values, belief systems, education, and economics.

The instrument used in the study was a survey designed by the author and arranged to secure data that would give a broad spectrum of the whole operation, in its varied and different components. The survey was distributed through the …

Is Nutrition Cai [Computer Assisted Instruction] An Effective Substitute For An Instructor, Deborah Falls Lockhart

Theses

Unavailable.

A Validation Study For Four Tests Of Behavioral Cognition, Kenneth J. Kish

Theses

This study is a predictive validity study employing subjects who were currently employed as psychiatric nurses on the four locked psychiatric units at Barnes Hospital, in St. Louis, Missouri. The purpose of the study was t o examine the relationship of four tests of social intelligence or behavioral cognition, and on the job performance, looking for a correlation between test scores and successful job performance . The criteria of job performance employed in the study were five scales designed by the researcher according to the behaviorally anchored scales model of performance reviews. Employees were rated by their respective supervisors using …

Small D.C. Bipolar Electromagnetic Design: Optimization And Analysis, John J. Breen

Theses

The design of electromagnets is an iterative process in which the designer arrives at a solution to his design problem through repeated design trials. This procedure can be time consuming, and the resultant configuration may or may not be the best one for the constraints imposed on it. In addition, the designer must have a reasonable knowledge of magnetics to carry out these design steps. This paper presents the basic equations necessary for designing and analyzing a horseshoe-shaped D.C. electromagnet. With this base, two methods are developed to optimize a design for maximum holding force, subject to prespecified constraints. The …

Experimental Quantification Of The Image Quality Loss Due To The Effect Of Screen Ruling, Chantana Tangseree

Theses

The purpose of this research is to measure the amount of image quality loss due to the effect of screening an image with halftone screens. This was done by using screens of different line number and images with differing amounts of image quality. Six black and white continuous tone positive originals were used to scale the image quality. These prints had been produced so as to have equal steps of image quality from the sharpest and ranging to some lower image quality which was at or slightly below a just acceptable level of image quality. Each of these images was …

Optimization Of A Photographic Shutter By Minimization Of Closing Time Variability, Steven D. Daniels

Theses

A photographic shutter was considered, comprised of a mechanically driven, pivoted opening blade and a spring driven, pivoted closing blade which is released by a magnetic holding coil through an armature lever. The magnitude of the viscous drag of air on the closing blade is approximated, and its effect on the travel time (lag time) of the blade is determined to be insignificant. A set of equations is derived representing the dynamic performance of the combination of the closing blade and the armature lever. These equations are used to develop a mathematical representation of the variation in lag time due …

In Vivo Spectral Absorption Analysis Enabling The Classification Of Pigmented Cutaneous Lesions: Investigating System Design And The Role Of Faculative Melanin In The Spectral Determination Of Skin Type Classification, Howard E. Mahran

Theses

A spectroradiometer was designed and built to record in vivo absorption characteristics of the lateral elbow. An analysis of variance of spectral characteristics between 400 and 1100 nanometers of faculative melanin to skin types one two and three was performed. The hypothysis that skin type could be differentiate by spectral recordings of in vivo faculative melanin was rejected. Further research is required to correlate constitutional melanin to skin type classification, in order to form a reference for pigmented cutaneous lesion classification.

Linearity Of An Electrophotographic Image Reproduction System, Lloyd Clark

Theses

The linearity of image transfer is analyzed for a high resolution electrophotographic film and electrodeveloper combination. The extent of nonlinearities introduced upon transfer through the photoconduction and electrodevelopment stages is conceptualized in terms of inherent physical mechanisms. A spectral shift in narrow band exposing radiation is used to test significance of exponential absorption on linearity of photoconduction transfer. Variations in development electrode spacing and development time test for nonlinearity induced by temporal and spatial frequency dependent depletion of electrodeveloper particles. As the electrophotographic film employed in the test exhibited low absorption coefficients in all spectral bands, exponential absorption of exposing …

Comparison Of Methods Of Mtf/Otf Analysis For Optical Systems, Jean Croteau

Theses

A comparison study for the methods of obtaining the MTF of optical systems was performed. It is demonstrated that non-Fourier methods are as good predictors of the MTF as are the Fourier methods. A new technique based on the moment theorem is introduced and is found to be a good predictor. A computer algorithm has been written to perform all the necessary operations.

Design Of A Photoreactor For The Oxidation Of Toxic Pollutants In Water By Ozone And Ultraviolet Radiation, Shahab Rashid Khan

Theses

A photoreactor has been designed to oxidize refractory chemicals found in water using ozone and ultraviolet radiation. The feasibility of the ozone/UV process has been examined by conducting experiments with three model compounds, namely, (1) o-chlorophenol (2) m-chlorophenol and (3) p-chloro phenol. For o-chlorophenol and p-chloro-phenol, reactions were very fast with ozone/UV oxidation and somewhat slower with m-chlorophenol. It is concluded that UV irradiation increases the decomposition of ozone and the resulting unstable intermediates are much more reactive than ozone. Ultraviolet light also helps in decomposing the substrate molecules. The effect of UV upon decomposition of ozone is more pronounced …

An Interactive Procedure For Numerical Design Optimization, Jaehwan Lee

Theses

An interactive version of the numerical design optimization method of Pappas for the solution of nonlinear optimization problems is presented in this thesis, A designer intervention strategy is employed herein for interactive optimization to allow the designer to control and manage the optimization process. This procedure embodied in the interactive CADOP6 program is tested on the ten bench mark problems of Eason and Fenton to illustrate the designer intervented optimization process and to provide a comparison with the fully automated procedure of Pappas This designer intervented interactive program appears more effective and faster than the completely automated CADOP5 code on …

Spectral Analysis Of Brainstem Auditory Evoked Responses, Amir Hossein Massumkhani

Theses

In this study, the power spectrum density of the brainstem auditory evoked responses is estimated by the method of periodogram. Several techniques for reducing the leakage due to the finite length of data, smoothing the spectrum and reducing the ambiguity in the spectrum due to the resolution are studied. It is shown that a Hamming window reduces the leakage considerably and zero extention of the data to 512 points produces sufficient spectrum bandwidth. Three major peaks are observed at 100, 500, and 1000 Hz which are stable for different evoked responses. In one case with a delayed wave V, the …

Measurement Of Thermal Conductivity Of Polymers Using Line Source Method, Manojkumar C. Patel

Theses

The purpose of this investigation was to evaluate the Line Source technique to measure the thermal conductivity of different molten polymers. Although the results obtained using this method are within acceptable experimental error limits, due to tec reasons explained, the results are not as accurate as claimed in the literature which describe this technique.

Radiation Heat Transfer Analysis Of A Czochralski Furnace With A Radiation Shield, Frederick A. Merz

Theses

This paper reports on the radiation heat transfer from the melt in a Czochralski crystal growing furnace in the presence of a radiation shield The change of radiation heat transfer effects three basic areas, the cooling rate of the crystal, the bulk flow and the bulk temperature of the melt. The shield is installed above the melt to inhibit the heat transfer from the melt to the cooling crystal, allowing the crystal to grow 40% faster. Radiation is the primary mode of heat transfer in the furnace where the temperature to grow silicon crystals is around 1773K. The governing equations …

Mathematical Model Of Temperature Profiles And Coking In A Crude Oil Heater Tube, Joseph C. Polimeni

Theses

A mathematical model to predict temperature profiles and coking of crude oil in furnace tubes is presented. The model assumes that the coking mechanism is due to a reaction in the laminar sublayer, whose rate depends upon the temperature profile. That profile is obtained by a numerical solution of the appropriate transport equations, with velocity profiles that may be laminar or turbulent, and including the temperature dependence of the crude oil properties. In addition, velocity and temperature profiles were adjusted when necessary to ensure closure of the heat and material balances. As a by-product of this study, a correction was …

The Quasisteady Approach For Thermal Analysis Of Frost Action Below Refrigerated Warehouses, Milan Kumar Bag

Theses

The quasisteady method of analysis has been used to determine the frost depth below refrigerated warehouses. For the case when the ground temperature is different from phase change temperature, the solution is obtained by numerical integration of the equation governing the phase change process. When the ground temperature approaches the phase change temperature closed form solution is obtained. The results obtained from the quasisteady method compare well with the experimental results. The results presented in this thesis should find use in the design of the refrigerated warehouses in the colder regions of the world.

Lifo Perishable Inventory (S,S,T) Model And Its Related Discount Policy, Yuan-Shyi Chiu

Theses

The objective of this thesis is to determine the optimal (s,S,T) ordering policy for a perishable inventory system with a fixed product lifetime and Poisson demand. The simulation technique is utilized to identify the optimal ordering policy which minimizes the total cost consisted of ordering, holding, shortage, and outdate costs. Upon the establishment of the optimal ordering policy, a discount policy on the outdating items is proposed to provide decision maker(s) with tradeoff between the profit and the average outdate cost.

The computer programs written in FORTRAN are designed to generate the optimal (s,S,T) ordering policy of any above-mentioned inventory …

Data Acquisition And Parameter Identification In Electro-Oculography, Wolfgang Poelzleitner

Theses

Electro-Oculography (EOG) is used in clinical ophthalmology to measure the time response of the corneoretinal potential (CRP) to changes in light intensity. An automatized data acquisition and system modeling link has been developed that significantly reduces processing time presently required for EOG. The data acquisition is performed on a microprocessor based instrument, which supervises the EOG-test, measures the potential and, after completion of the test, transfers the results to a mainframe computer. Parameter identification routines provide graphical representation and mathematical models for the CRP. Both nonlinear curve fitting methods and Least Squares System Identification schemes are used.

Landscape: Inside And Out, Linda E. Mccausland

Theses

Not Included

Effect Of Title Iv-B Funding In St. Charles County Public Libraries, 1976-1982, Lucinda Menkhus

Theses

In 1974 Congress consolidated several existing educational programs into the Elementary and Secondary Education Act Title IV. Part B of that bill was designed to provide instructional materials for schools. A majority of Title IV-B money nationwide was used to purchase library books, audiovisual hardware, and audiovisual software.

This study was designed to examine the possible benefits Title IV-B funding had on St. Charles j County school libraries. Between 1976 and 1982, 15 school libraries were able to meet Missouri State standards in the size of the collection category. This study was needed to show that Title IV-B played an …

A Curriculum Guide For Training Teachers Of Students Who Are Blind/Low Vision In Tanzania, East Africa, Jean Latimore Smith

Theses

This is a project for training teachers of students who are blind or have low vision in Tanzania, East Africa. Blindness is viewed as one of the most feared disabilities to afflict mankind . There are millions of people throughout the world who are blind or have low vision; young-old, men-women, boys-girls, black-white, rich- poor, there are no barriers . In Tanzania, East Africa, £or every 100,000 people in certain areas, there are an estimated 500 people who are blind. It is because of this high incidence that this project is written . Since research does not indicate any concrete …

Geometric Abstract Design, Sanghye Han

Theses

This thesis is a presentation of four grid designs. They are woven on a multi-harness loom and utilize a strip-weaving technique. The designs are based on a series of colors, and consist of three grid elements; the line, the square and the rectangle. Through the variation of colors and the repeated arrangement of patterns consisting of the aforementioned grid elements, my intention is to have a form of geometric abstraction result from my designs.

A Model To Predict The Reflectance From A Concrete Surface As A Function Of The Sun-Object-Image Angular Relationship, George C. Grogan

Theses

A study was made of the variation in the reflectance of a concrete sample as the sun-object-image angular relationship was varied. The research work was performed in the controlled conditions of a laboratory so that atmospheric effects could be neglected. Reflectance measurements were taken from a. concrete sample whose surface roughness had been measured. Both specular and diffuse illumination in the red (630 - 680nm) wavelength region of the visible spectrum were measured. A model which can be used to predict the reflectance value for a given sun-object-image angular relationship was developed. Actual reflectance measurements taken outdoors agreed to within …