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A Study of Numerically Controlled Machines
This is a study of numerical control, its application, and the design of a numerical control program for a drilling machine. The study sought to obtain information on the function of numerical control; the different types of numerical control used by industry; and, the advantages of using numerical control.
Date:
August 1967
Creator:
Chan, John C. H.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
How Hitler Controlled the Press
Adolf Hitler advocated total control of the press for many years before he was elected Führer. Almost immediately after he assumed power in 1932, Hitler began writing new laws and regulations that totally exorcised all freedoms from the German press. This study follows the path that Hitler took to control the German press from 1920 until the end of World War II. It utilized translations of documents and statements by men whom Hitler appointed to control the press and books written by experts in the fields of communications as well as men who prosecuted Nazi war criminals after World War II. The study found that the control of the press was indeed a very necessary ingredient in Hitler's climb to power and remained crucial during his reign as Führer.
Date:
May 1982
Creator:
McConal, Billy Jon
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Principles and Application of Numerically Controlled Machines
The purpose of this study is threefold. First, numerical control will be analyzed objectively to ascertain its justification in terms of meeting the requirements of the basic manufacturing process phases. Secondly, the study will consist of an evaluation of the field of industrial arts in the Dallas-Fort Worth area to determine how numerical control has been accepted in the educational field and what preparation, if any, is being made to include the teaching of this new industrial concept. Thirdly, the study will investigate the feasibility and cost of installing numerically controlled equipment in the industrial arts laboratories of North Texas State University.
Date:
May 1968
Creator:
Koehler, Richard A.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Neutralization of the Figure Within a Controlled Environment
The questions I have addressed in regard to neutralization were as follows: 1. How important was the figure to the environment? 2. How far could the figure's physical presence be reduced and still contribute to the concepts of the painting? 3. How vividly was the figure presented while still complying with the requirements to meet neutralization? 4. Did color and texture aid in neutralizing the figure, and, if so, how? 5. Did the scale of the paintings have any effect on the neutralization process?
Date:
August 1979
Creator:
Gibson, John R.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The List
The List is a collection of short stories focusing on the inability to adapt, or learn from self-destructive patterns, and the bizarre ways people reach out for one another when they don't know what else to do.
Date:
December 2009
Creator:
O'Brien, Tanner Chase
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Dynamic Resource Management in RSVP- Controlled Unicast Networks
Resources are said to be fragmented in the network when they are available in non-contiguous blocks, and calls are dropped as they may not end sufficient resources. Hence, available resources may remain unutilized. In this thesis, the effect of resource fragmentation (RF) on RSVP-controlled networks was studied and new algorithms were proposed to reduce the effect of RF. In order to minimize the effect of RF, resources in the network are dynamically redistributed on different paths to make them available in contiguous blocks. Extra protocol messages are introduced to facilitate resource redistribution in the network. The Dynamic Resource Redistribution (DRR) algorithm when used in conjunction with RSVP, not only increased the number of calls accommodated into the network but also increased the overall resource utilization of the network. Issues such as how many resources need to be redistributed and of which call(s), and how these choices affect the redistribution process were investigated. Further, various simulation experiments were conducted to study the performance of the DRR algorithm on different network topologies with varying traffic characteristics.
Date:
December 2001
Creator:
Iyengar Prasanna, Venkatesan
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Cue-Controlled Relaxation: Saving Time Versus Efficacy
Cue-controlled relaxation is looked at to determine whether a component is efficacious as the entire procedure. Subjects were 40 male and 40 female undergraduates. Subjects were randomly assigned to one of four conditions: cue-controlled relaxation, progressive muscle relaxation, breathing exercises with a paired. cue word, on a presentation of the cue word without being paired. It was hypothesized that cue-controlled relaxation would be superior to a component of cue-controlled relaxation. It was determined that cue-controlled relaxation is not more efficacious than a particular component. Data suggests the majority of anxiety reduction takes place when the treatment focuses on the same modality from which the subject receives the most information about their anxiety. Implications and suggestions for further research are presented.
Date:
August 1983
Creator:
Todd, John Bruce
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Novel Phase-Chance Soft Actuators Controlled via Peltier
Soft actuation methods are a developing field of robotics deemed suitable for physical human-robot interactions due to the adaptability of materials and compliant structures. Thermo-active soft actuators are a subset of these which convert thermal energy to mechanical work in the form of elongation, bending, or twisting to conform to the environment. This study is divided into three major studies that all use actuators with a working principle of phase-change fluid vaporizing for expansion with applied heat from a Peltier. The first study evaluates the bandwidth and efficiency between (i) traditional Joule heating, and (ii) Peltier heating, finding that Peltier heating can considerably improve the operational bandwidth of the actuator. The second study uses a thin membrane actuator placed in a braided mesh to form a McKibben muscle capable of lifting 5N, and formed into a gripper capable of manipulating objects within the environment. The third study uses actuators of a solid, hollow and flexible Peltier embedded silicone structure and are evaluated and optimized in order to increase actuation speed, finding that the embedded flexible Peltier design was able to elongate over 50% of its original height in 20 seconds. The overall aim of all of these studies was to …
Date:
July 2023
Creator:
Johnson, Daniel Cody
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Pressure Controlled Topochemical Polymerization in Two-Dimensional Hybrid Perovskite
Mechanical pressure offers unique control over the energy landscape of chemical reactions, opening up pathways that are inaccessible through conventional thermochemistry. We hypothesize that the reduced dimensionality defines the conformational space of the high-pressure reaction, giving rise to new selectivity that is unavailable in 3D systems. Here, we demonstrate this concept through the pressure-controlled topochemical polymerization of the diacetylene molecule deca‐3,5‐diyn‐1‐amine (DDA) incorporated in the two-dimensional (2D) perovskite [DDA]2PbBr4. Compression at 3 GPa drives the first topochemical polymerization through 1,2 addition, forming a polyene product at room temperature. The reaction is initiated by the mechanical bending of the linear DDA molecule, a mechanism fundamentally different from the 1,4-addition in 3D solids. Importantly, pressure hinders the second 1,2-addition by disfavoring the gauche conformation between the remaining acetylene groups, allowing for the selective formation of polyene versus polyacene products. We characterize the reaction mechanisms and products using spectroscopies (Raman, X-ray photoelectron, ultraviolet-visible), X-ray diffraction and density-functional theory simulations. These results highlight the important role of dimensionality in high-pressure chemistry, and offers a new paradigm for creating low-dimensional functional materials.
Date:
December 2021
Creator:
Abu-Amara, Lama Marwan
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
A Voltage-Controlled Incandescent Lamp Driver for Musical Performances of Multimedia Works
Performances of multimedia works are hampered by the difficulty of controlling large numbers of incandescent lamps rapidly and accurately. The instrument described in this document is aimed at alleviating this problem. Chapter I describes the design and operation of the voltage-controlled dimmer unit and the DC controller. Chapter II describes step-by-step procedures for building the instrument. Schematics, wiring diagrams, and illustrative photographs are included. Chapter III discusses some of the aesthetics and philosophy of multimedia composition, and then describes various scenarios which utilize the instrument. Included are the connection of peripheral control equipment, audio/Video interfacing, and the potential for constructing prepared tapes which will automatically drive the dimmers. The prototype was built at the NTSU Electronic Music Center.
Date:
August 1975
Creator:
Balentine, Bruce
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Effects of a Remote-Controlled Tactile Prompt on the Initiation Skills of a Child with Autism
A 4-year old child with autism was taught to make a social initiation statement following a remote-controlled tactile prompt (RCT). The RCT prompt was taught by using a time-delay procedure with written script cards containing initiation statements. Training trials occurred in 6 different play locations in the child's room. Restricted Trial training consisted of allowing the child to play independently, activating the RCT prompt and playing with the child based on any initiation until a warning to end was given. In Free Play training, the warning to end the activity was removed. The child's initiation statements increased from 0 in baseline, to spontaneous initiations in 100% of the trials in all training and generalization phases. The number of words in an initiation statement increased from 3 to 25 per trial. Spontaneous initiations in the No RCT phase generalized to the child's mother without training.
Date:
August 1999
Creator:
Bingham-Watts, Kera L.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
A Study to Develop a Curriculum Guide for Use in Teaching Numerically Controlled Drafting Courses
The problem with which this study is concerned is that of developing a curriculum guide educators can use in planning and organizing a course of study involving computer drafting at the junior college and technical vocational school levels. This study is also concerned with the impact of computer drafting on the present drafting curriculum.
Date:
December 1970
Creator:
Driskell, Hollis E.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Virtual Classroom As a Tool for the Assessment of Automatic and Controlled Processing in Autism Spectrum Disorders
Assessment of executive functioning in neurodevelopmental disorders (e.g., autism) is a crucial aspect of neuropsychological evaluations. The executive functions are accomplished by the supervisory attentional system (SAS) and include such processes as inhibition, switching, and planning. Autism spectrum disorder (ASD) tends to present similarly to other neurodevelopmental disorders (e.g., ADHD). For example, ASD and ADHD may share similar etiological underpinnings in the frontostriatal system of the frontal lobe. Research on executive functioning in ASD has been mixed, thus the precise nature of executive functioning deficits in ASD remains equivocal. In recent years, simulation technologies have emerged as an avenue to assess neurocognitive functioning in individuals with neurodevelopmental disorders impacting frontostriatal function. Simulation technology enables neuropsychologists to assess neurocognitive functioning within a testing environment that replicates environments in which the subject is likely to be in everyday life, as well as present controlled, real-world distractions, which may be better able to tap “hot” executive functions. A Virtual Classroom Continuous Performance Test (CPT) has been used successfully to assess attention in individuals with neurodevelopmental disorders impacting frontostriatal function. The current study aimed to investigate executive functioning in individuals with high functioning ASD using a new construct driven Stroop assessment embedded into the …
Date:
August 2015
Creator:
Carlew, Anne R.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Attainment of Low Levels of Muscle Tension: Biofeedback-Assisted/Cue-Controlled Relaxation and Biofeedback Training Compared
Cue-controlled relaxation appeas to have several advantages over prominent anxiety-reduction treatments. It does not require the formulation of conditioned stimulus hierarchies nor the use of mental imagery as does systematic desensitization nor the application of noxious stimularion (farradic shock) utilized in anxiety relief. However, its efficacy, in quantitative terms, has not been determined. The present study compared the effectiveness in attainment of relaxation of instructional set, biofeedback training, and biofeedback-assisted/cue-controlled relaxation training procedures. Results indicate that cue-controlled relaxation training was more effective in terms of mean level of frontal is EMG and degree of maintenance of low EMG levels than either biofeedback training or instructions.
Date:
August 1978
Creator:
Ewing, Jack Winston
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Exploring the Effects of Cultural Consequences Identified through a Ranking Task on the Interlocking Behavioral Contingencies of Ethically Self-Controlled Responses with Participants with Pre-Existing Relationships
This study explored the effects of cultural consequences identified through a ranking task on the selection of interlocking behavioral contingencies and aggregate products constituting ethically self-controlled responses when participants had pre-existing relationships. Two experiments were conducted to explore these effects. Experiment 1 had two triads of three participants each recruited from a university-based autism center. Experiment 2 had three triads of three participants each; participants in Triads 3 and 4 were recruited from a university-based rock-climbing club while participants in Triad 5 were recruited from the same university-based autism center as in Experiment 1. All participants were exposed to a task that involved choosing odd or even rows from a matrix displayed throughout the experimental session. Individual contingencies were programmed in all conditions while metacontingencies were programmed in some conditions. Participants selected the topography of the cultural consequence through a pre-experimental ranking task prior to the onset of the experimental session. A change was made to the experimenter's verbal behavior in all operant and metacontingency conditions for Experiment 2. The results of both experiments indicate that identification of the cultural consequence through a ranking task with participants having pre-existing relationships did have an effect on the continued selection of the …
Date:
May 2022
Creator:
Elwood, Chelsea Christina
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Design and Optimization of Components in a 45nm CMOS Phase Locked Loop
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A novel scheme of optimizing the individual components of a phase locked loop (PLL) which is used for stable clock generation and synchronization of signals is considered in this work. Verilog-A is used for the high level system design of the main components of the PLL, followed by the individual component wise optimization. The design of experiments (DOE) approach to optimize the analog, 45nm voltage controlled oscillator (VCO) is presented. Also a mixed signal analysis using the analog and digital Verilog behavior of components is studied. Overall a high level system design of a PLL, a systematic optimization of each of its components, and an analog and mixed signal behavioral design approach have been implemented using cadence custom IC design tools.
Date:
December 2006
Creator:
Sarivisetti, Gayathri
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Simulink® Based Design and Implementation of a Solar Power Based Mobile Charger
Electrical energy is used at approximately the rate of 15 Terawatts world-wide. Generating this much energy has become a primary concern for all nations. There are many ways of generating energy among which the most commonly used are non-renewable and will extinct much sooner than expected. Very active research is going on both to increase the use of renewable energy sources and to use the available energy with more efficiency. Among these sources, solar energy is being considered as the most abundant and has received high attention. The mobile phone has become one of the basic needs of modern life, with almost every human being having one.Individually a mobile phone consumes little power but collectively this becomes very large. This consideration motivated the research undertaken in this masters thesis. The objective of this thesis is to design a model for solar power based charging circuits for mobile phone using Simulink(R). This thesis explains a design procedure of solar power based mobile charger circuit using Simulink(R) which includes the models for the photo-voltaic array, maximum power point tracker, pulse width modulator, DC-DC converter and a battery. The first part of the thesis concentrates on electron level behavior of a solar cell, …
Date:
May 2016
Creator:
Mukka, Manoj Kumar
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Program Components for a Corporate Wellness Program
This study was to determine if the importance assigned by health educators (judges) to components of corporate health promotion programs is the same as or different from program components most frequently offered by corporations for employees. This involved establishing a list of program components that judges felt were important for wellness programs and comparing this list with programs actually existing in polled corporations. A literature review was used to establish an initial list of program components. Thirty-eight judges returned questionnaires incorporating the list. A Spearman's rho and scattergram were used to test for correlations between judges' opinions and corporate practices. The report concludes that no correlation exists but that there is agreement among the judges polled that corporations should promote employee wellness programs.
Date:
May 1984
Creator:
McNeely, Jerry J.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Effect of Retting on Surface Chemistry and Mechanical Performance Interactions in Natural Fibers for High Performance Polymer Composites
Sustainability through replacement of non-renewable fibers with renewable fibers is an ecological need. Impact of transportation costs from South-east Asia on the life cycle analysis of the composite is detrimental. Kenaf is an easily grown crop in America. Farm based processing involves placing the harvested crop in rivers and ponds, where retting of the fibers from the plant (separation into fibers) can take 2 weeks or more. The objective of this thesis is to analyze industrially viable processes for generating fibers and examine their synergistic impact on mechanical performance, surface topography and chemistry for functional composites. Comparison has been made with commercial and conventional retting process, including alkali retting, enzymatic retting, retting in river and pond water (retting occurs by natural microbial population) with controlled microbial retting. The resulting kenaf fibers were characterized by dynamic mechanical analysis (DMA), Raman spectroscopy (FT-Raman), Fourier transform infrared spectroscopy (FT-IR), polarized optical microscopy (POM), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) optical fluorescence microscopy, atomic force microscopy (AFM) and carbohydrate analysis. DMA results showed that pectinase and microbe treated fibers have superior viscoelastic properties compared to alkali retting. XPS, Raman, FT-IR and biochemical analysis indicated that the controlled microbial and pectinase retting was …
Date:
May 2013
Creator:
Ramesh, Dinesh
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Treatment of Migraine Headache Utilizing Cerebral Electrostimulation
Cerebral electrostimulation (CES) as a treatment for migraine headache was investigated. Eighteen participants recorded data on headaches for two baseline weeks. Six were assigned to each of three groups--an active treatment group receiving CES, a placebo group receiving a simulated version of CES, and a no-treatment control group placed on a waiting list during the study. The CES group evidenced a significant reduction in headache duration and intensity relative to the placebo group. The waiting list control group did as well as the CES group. A number of hypotheses were put forth in an attempt to account for the unexpected finding.
Date:
December 1976
Creator:
England, Ronald R.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Processing, Structure, and Tribological Property Interrelationships in Sputtered Nanocrystalline ZnO Coatings
Solid lubricant coatings with controlled microstructures are good candidates in providing lubricity in moving mechanical assembly applications, such as orthopedics and bearing steels. Nanocrystalline ZnO coatings with a layered wurtzite crystal structure have the potential to function as a lubricious material by its defective structure which is controlled by sputter deposition. The interrelationships between sputtered ZnO, its nanocrystalline structure and its lubricity will be discussed in this thesis. The nanocrystalline ZnO coatings were deposited on silicon substrates and Ti alloys by RF magnetron sputtering with different substrate adhesion layers, direct current biases, and temperatures. X-ray diffraction identified that the ZnO (0002) preferred orientation was necessary to achieve low sliding friction and wear along with substrate biasing. In addition, other analyses such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) were utilized to study the solid lubrication mechanisms responsible for low friction and wear.
Date:
August 2009
Creator:
Tu, Wei-Lun
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Toward an Experimental Analysis of a Competition between Dimensions of Cultural Consequences
The exponential growth of the human population has contributed to the overuse and degradation of common pool resources. Using science as a tool for informed policy-making can improve the management of our common pool resources. Understanding the conditions that influence groups of individuals to make ethical self-controlled choices may help solve problems related to the overuse and degradation of common pool resources. Ethical self-control involves the conflict of choice between one that will benefit the individual versus one that will benefit the group. The cumulative effect of many individuals behaving in an ethically self-controlled manner with common resource use may offset some of the harm posed by overuse of common pool resources. Metacontingency arrangements involving ethical self-control may provide some insight as to if and how groups may cooperate to manage a common pool resource. This manuscript proposes an experimental preparation and methodology to evaluate the effects of competing magnitudes of cultural consequences on culturants and their cumulative effect on common pool resources; and provides an analysis and discussion of five trends that might result from such a line of research.
Date:
August 2020
Creator:
Guerrero, Maria Brenda
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Use of GIS to Identify and Delineate Areas of Fluoride, Sulfate, Chloride, and Nitrate Levels in the Woodbine Aquifer, North Central Texas, in the 1950s, 1960s, 1970s, 1980s, and 1990s
ArcView and ArcInfo were used to identify and delineate areas contaminated by fluoride, sulfate, chloride, and nitrate in the Woodbine Aquifer. Water analysis data were obtained from the TWDB from the 1950s to 1990s covering 9 counties. 1990s land use data were obtained to determine the relationship with each contaminant. Spearman's rank correlation coefficients and Kruskal-Wallis tests were used to calculate relationships between variables. Land uses had little effect on distributions of contaminants. Sulfate and fluoride levels were most problematic in the aquifer. Depth and lithology controlled the distributions of each contaminant. Nitrate patterns were controlled mainly by land use rather than geology, but were below the maximum contaminant level. In general, contaminant concentrations have decreased since the 1950s.
Date:
August 2001
Creator:
Sanmanee, Sirichai
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Impact of Processing Parameters and Forces on Channels Created by Friction Stir Bobbin Tools
In this thesis, friction stir channeling (FSC) and its process parameters influence on geometry, surface quality and productivity are explored. The probe of the friction stir processing (FSP) tool used to perform these tests was a modified submerged bobbin tool made of MP 159 Co-Ni alloy. The body was made from H13 tool steel. To find the optimal channel conditions for a targeted range of process parameters, multiple 6061 aluminum samples were prepared with a U shape guide to test the effects of different spindle speeds and feed rates. Using a gantry-type computer numerical control (CNC) friction stir welding (FSW) machine, the aluminum coupons were subjected to calibration experiments, force control tests, and an increased production rate to test these effects. It was found through experimentation that the programmed feed rates, spindle speeds and forces produced by the machine had an impact on the channel geometry. It was determined from the force-controlled setup that 8.46 mm/s at 750 RPM was the best combination of results for the four conditions tested on a CNC friction stir processing-machine. It was then tested at 10.58 mm/s at 800 RPM, which had comparable results with the best combination of input parameters from the force-controlled …
Date:
May 2022
Creator:
Koonce, James G
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library