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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Literature review of rock properties for analysis of navigation structures founded on rock

Benson, Carl Philip 15 November 2013 (has links)
A review of behavioral rock properties used for input to the finite element method are summarized. Rock properties presented in the literature were primarily obtained from laboratory specimens. Methods to determine applicable field properties via testing, calculations and empirical correlations are included. Suggested behavioral properties of the structural concrete-to-rock interface are proposed. Specific property values, resulting from the literature review, are presented as input for a finite element parametric evaluation of navigation structures. / Master of Science
272

The development of a continuous peanut drier

Cannon, Buford Mullis 15 November 2013 (has links)
This study indicates that peanuts can be dried continuously using supplemental heat and still retain a palatable flavor. It has brought to focus many problems heretofore recognized. / Master of Science
273

Handweavers' enduring product involvement with craft yarns and selected information processing variables

Rendleman, Susan Ruth 11 June 2009 (has links)
This study investigated attributes of craft yarns of most interest to handweavers, sources of information used by handweavers to learn about craft yarns, and methods used by handweavers to communicate information about handwoven textiles to ultimate consumers. In addition, the extent of the sample group of handweavers’ knowledge of Federal Trade Commission TRR 16 C.F.R. 423 on care labeling for garments was examined. Finally, relationships between information processing behaviors drawn from the theory of enduring product involvement were examined. The survey was returned by 81 handweavers from four handweaver’s guilds in three Southeastern states. The yarn attribute with the highest importance rating was "matching the type of yarn to what it will be used for" with a mean importance rating of 5.649 out of 6. Important sources of care information for handweavers were experience, yarn wrappers, and other weavers. On the yarn wrapper, the most important information was fiber content and length in yards. Also of strong importance were washfastness rating, written care instructions, and lightfastness rating. Only two of seventeen weavers who sold their products included a permanently attached care label as required by law. And 70% of the weavers incorrectly believed that a paper hang tag was an acceptable care label for a garment when it was sold. Five elements of enduring product involvement were operationalized in the instrument: centrality to egoidentity, hedonic value, self-reported expertise, craft-related activities, and specialized fiber-art interests and activities. Each of the five elements had a high positive correlation to the overall score (p < .0001). The correlation between the involvement score and information seeking behavior frequency score was low, (0.345) but significant (p < .001), while the correlation between the involvement score and importance of attributes was not significant. / Master of Science
274

Study of truck allocation and truck dispatching problems in open pit mines

Maran, Juliano 17 November 2012 (has links)
In recent years, fierce competition, rising production costs and depressed prices for mineral products, have forced mining companies to find ways to improve efficiency and lower production costs. Given the fact that loading and hauling operations account for up to 60 % of the total costs in surface mining, the optimization and control of these operations can provide substantial reductions in the costs. Assignment of truck to shovels has been traditionally performed by fixed truck allocation and by truck dispatching. Several operations research and simulation techniques, which can be used to solve problems concerning surface mining operations, are discussed. The types of problems addressed are: how to allocate trucks to loading equipment, how to evaluate the performance of an existing operation, and how to predict the performance of a future system. For truck allocation, operations research methods such as: dynamic programming, integer programming, and heuristic algorithms are discussed. These methods are used mainly for decision making purposes. Queuing theory techniques, also analyzed, are used mainly for evaluation purposes. / Master of Science
275

The effects of hearing protection on speech discrimination in differing noise spectra

Horylev, Matthew James 17 November 2012 (has links)
This research project was aimed at investigation of speech communication issues in industrial noise environments where workers utilize hearing protection devices (HPDs). A controlled empirical study was conducted to determine the effects of several independent variables on speech reception and discrimination including: l). subject's hearing configuration (unoccluded or earplug, earcap, earmuff-occluded), 2). ambient noise intensity level (60, 83 dBA), 3). ambient noise spectral type (low, white approximation, high frequency), 4). speaker's voice level (63 or 65 dBA in 60 dBA noise, 82 or 88 dBA in 83 dBA noise), and 5). subject's hearing level (normal hearing, slight loss, or moderate loss) used as a blocking variable. Isophonemic word discrimination, with male-voiced word lists presented through loudspeakers in an anechoic field, served as the experimental task. Twenty-three males and twenty-two females participated in the experiment and a mixed-factors, partial hierarchical design was used for data collection. Analysis of variance and Newman-Keuls multiple-range tests were applied to the data. All main effects, with the exception of hearing level blocks, were significant, in addition to several interactions. These are discussed in detail and depicted graphically. One fundamental finding was that none of the hearing protection devices degraded speech discrimination (in comparison to an unoccluded condition) in the 83 dBA ambient noise level. In fact, the most protective HPD significantly enhanced speech discrimination in the high noise level. In the low ambient noise level, there was some reduction in discrimination due to the wearing of an HPD, but this effect is not of concern because HPDs are not needed at low ambient levels for protection purposes. From the results, it appears that properly selected HPDs can be expected to at least maintain speech discrimination levels (equivalent to unoccluded levels) in moderately-high intensity industrial noises of varied spectral characteristics. / Master of Science
276

A study to determine the optimum accomplishments for Virginia high school students on certain office machines

Greene, Richard Sherman 07 November 2012 (has links)
There appears to be little difference in student accomplishment on the operations of the different machines regardless of the number of hours of training. There was no significant increase in the number of correct problems from the lâ 5 hour training period to the 16-20 hour training period on many of the machine operations. / Master of Science
277

Testing of a counter-flow, stack-type sawdust dryer

Grace, Laura A. 21 November 2012 (has links)
The objective of this research was to test a prototype sawdust dryer designed by Arrowhead Forest Products, a wood products firm based in St. Louis. The dryer is designed to be used by small to medium sized sawmills and pallet mills. A series of 50 one hour or longer trials were conducted to develop operating parameters and test the sensitivity of the dryer performance to species, operating speed, throughput rate and Xi atmospheric conditions. Performance criteria measured included moisture content removed, final moisture content and pounds of water removed per hour in the entire system and the individual system components. Performance measures were developed from 30 one kilogram sawdust samples collected during each trial. The sampling procedure paired samples pulled with temperature profiles across the dryer and ambient weather conditions. Analysis of variance and analysis of covariance were used to explore relationships and interactions between the variables of interest. The system proved capable of removing 10% to over 60% of the initial moisture in the sawdust. The amount of drying that occurred was dependant on the throughput rate of sawdust. The overall energy efficiency of the system was approximately 60%. / Master of Science
278

Psychophysical assessment of load-carrying in internal and external-frame backpacks

Meunier, Pierre 02 May 2009 (has links)
The psychophysical method of adjustment was used to determine whether slight changes in load position and comfort could have significant effects on the maximum backpack load acceptable to subjects. Four males and four females, who were accustomed to walking with backpacks, were given 15 minutes to adjust the load until it was, in their judgment, neither too heavy nor too light for an 8-hour trek. The variables in this 2³ within-subject experimental design were horizontal and vertical load position, as well as backpack type. The levels of the horizontal load position differed by a distance of 4.0 cm, which corresponds to the difference between the internal and external-frame backpacks used in the experiment. The vertical distance levels were 1/3 and 2/3 of the height of the pack. The pack types (internal and external-frame) were selected on the basis of their harnesses, to provide two distinct levels of comfort. The results indicated that the horizontal and vertical load positions did not have an appreciable effect on the psychophysically determined maximum acceptable load, although there was a significant interaction between the horizontal position and pack type. There was a significant difference in trunk angle due to Pack type and Horizontal load position. The stride rate was not affected by the treatment conditions, but it decreased significantly with the addition of load. There was a significant difference in comfort ratings between backpacks, with subjects choosing to carry 6% larger loads in the one they rated as more comfortable (the external-frame backpack). / Master of Science
279

Efficiency studies with different types of dairy barn equipment and barn arrangements

Howe, James Wheelock January 1951 (has links)
This study was made to secure data on the use of different types of barn equipment and bam arrangements. The following outline lists the various phases of the study. Outline of Investigation 1. Efficiency of labor with different types of barn equipment and barn arrangements a. Cleaning and brushing cows b. Cleaning stalls c. Removing manure from barn d. Feeding cows roughage and grain (1) Feeding silage (2) Feeding hay (3) Feeding grain e. Fastening and unfastening cows in stalls f. Location of milker vacuum lines 2. Efficiency of different types of stalls a. Amount of bedding require b. Cleanliness of cows c. Feed wastage d. Comfort of cows e. Production / Master of Science
280

An air sampling system to estimate concentrations of argon-41 in the V.P.I. physics building during reactor operation

Putney, Irvin Turner January 1963 (has links)
A gamma scintillation spectrometer was assembled. and calibrated in a low background radiation area to analyze air samples. Air samples were taken from different locations in the physics building during reactor operation to determine the concentrations of A⁴¹ released to the surroundings of the building during reactor operation. The samples were collected in a one gallon polyethylene bottle with a 3 ¾” x 3 ¾” cylindrical well sealed in the bottom. The air samples were taken to the counting area and the sampling bottle placed on the detector, a 3” x 3" cylindrical NaI(TI) crystal which fitted into the well. The pulses from the detector were fed te a multi-channel analyzer. From the number of pulses per unit time under the photo-peak, the concentration of A⁴¹ for each location was determined. Samples were analyzed for 4, 7, and 10 kw from which a linear extrapolation was made to estimate the concentrations of A⁴¹ in these locations if higher power operation is authorized. / Master of Science

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