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Development of Commercial Applications for Recycled Plastics Using Finite Element AnalysisNarasimhamurthy, Nanjunda 15 November 2005 (has links) (PDF)
This thesis investigates the suitability of thermo-kinetically recycled plastics for use in commercial product applications using finite element analysis and statistics. Different recycled material blends were tested and evaluated for their use in commercial product applications. There are six different blends of thermo-kinetically recycled plastics used for testing and CATIA is used for finite element analysis. The different types of thermo-kinetically recycled plastics blends are: pop bottles made of PolyethyleneTeraphthalate (PET), milk jugs made of High-Density Polyethylene (HDPE), Vinyl seats made of Poly Vinyl Chloride (PVC) and small amount of Polypropylene (PP) and Urethane, electronic scrap made of engineering resins like Acrylo-Nitrile-Butadiene Styrene (ABS), Polystyrene (PS) and Polycarbonate (PC), agriculture waste consisting of Low Density Polyethylene (LDPE), industrial waste consisting of Nylon (PA66) and PolyethyleneTeraphthalate (PET), household waste consisting of Polystyrene (PS). The methods employed during the study include three phases for each of six blends available: 1.Density, tensile and impact testing of each blend 2.Correlation of mechanical properties to blend 3.Finite element analysis of the service performance of a product made from each thermo-kinetically recycled plastic blend This thesis shows that some of the recycled plastics materials that were tested are qualified to be used in the pallet. Those materials that qualified were Industrial waste consisting of Nylon and PolyethyleneTeraphthalate, household waste consisting of Polystyrene.
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Significant Trade Contractor Performance Characteristics as Evaluated by Big-D ConstructionJohnson, Conrad C. 20 March 2007 (has links) (PDF)
The purpose of this research is to determine which aspects, other than price, of trade contractor performance are the most important to the general contractor, Big-D Construction. The impression a trade contractor leaves on the project manager and superintendent provides an indication of their performance. To determine what tasks trade contractors perform that most greatly impact overall perception of the general contractor's project manager and superintendent, hundreds of trade contractors were evaluated in ten separate categories and were then given an overall rating. The correlation between each category and the overall rating was found. The categories were then sorted from highest correlation to lowest. Of the ten categories, professionalism had the highest correlation. Next to professionalism, schedule adherence was found to be most important. All of the next six categories: Coordination with other subs, quality of work, technical knowledge of drawings & specs, project close out (O&M's, punchlist, as-builts), monthly invoices - timely and accurate, and accuracy/timeliness of change orders, all had similar impact on overall performance. Daily clean-up and safety attitude, had the least impact on performance, with safety falling significantly lower than every other category. Overall, being professional, keeping to the schedule and doing good work are most important to project management teams, while keeping the job clean is noticeably less and safety is much less important.
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Objective Test Methods for Waveguide Audio SynthesisWood, Steven Gregory 21 March 2007 (has links) (PDF)
Acoustic Physical Modeling has emerged as a newer musical synthesis technique. The most common form of physical modeling synthesis in both industry and academia is digital waveguide synthesis. Commercially available for the past thirteen years, the top synthesizer manufacturers have chosen to include physical modeling synthesis in their top of the line models. In the area of audio quality testing, the most common tests have traditionally been group listening tests. While these tests are subjective and can be expensive and time-consuming, the results are validated by the groups' proper quality standards. Research has been conducted to evaluate objective testing procedures in order to find alternative methods for testing audio quality. This research has resulted in various standards approved by the International Telecommunication Union. Tests have proven the reliability of these objective test methods in the areas of telephony as well as various codecs, including MP3. The objective of this research is to determine whether objective test measurements can be used reliably in the area of acoustic physical modeling synthesis, specifically digital waveguide synthesis. Both the Perceptual Audio Quality Measure (PAQM) and Noise-To-Mask Ratio (NMR) objective tests will be performed on the Karplus-Strong algorithm form of Digital Waveguide synthesis. A corresponding listening test based on the Mean Opinion Score (MOS) will also be conducted, and the results from the objective and subjective tests will be compared. The results will show that more research and work needs to be done in this area, as neither the PAQM nor NMR algorithms sufficiently matched the output of the subjective listening tests. Recommendations will be made for future work.
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A New Spectroscopic Method for the Non-Destructive Characterization of Weathering Damage in PlasticsGeorge, Andrew Robert 20 November 2006 (has links) (PDF)
The weathering of plastics and composites is a problem because of the loss of both physical and mechanical properties that it causes in these materials. But this weathering effect has been difficult, and in some cases, impossible to characterize without the destruction of the plastic or composite part. Clearly a rapid, reliable, and non-destructive test for the extent of the weathering damage is critically needed. A recent problem that arose at Superyacht Solutions, a boat repair company in Australia, required a solution to just this problem. Such a test was developed for Superyacht Solutions, and is being applied across a wide range of plastic materials. The chemical foundation upon which this solution rests is also being confirmed. The Superyacht Solutions problem was that a boat was brought in for repair which was yellowing dramatically. Surface erosion was confirmed by scanning electron microscope (SEM) surface studies. A loss of mechanical properties was also suspected. A new spectroscopic method of analysis was developed that not only identified the problem as extensive oxidation, but was able to quantify the extent of damage that occurred through a non-destructive technique. This method has also been applied to other plastics with encouraging initial results. The method used and its theoretical basis are included in this thesis.
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A Solution for Commodity Field Hauling with Self-Unloading Semi-TrailersWilkerson, Lee Pagens 14 July 2006 (has links) (PDF)
Commodity hauling of bulk goods is a growing enterprise that has expanded from hauling agricultural products to hauling many other bulk products. Commodity trailers are used to haul agricultural products from storage facilities to processing plants. These trailers are designed for highway use but are frequently required to work in field conditions as well. In many cases this environment overstresses these trailers and results in permanent irreparable damage. In addition to the structural problems of these trailers, the current systems for unloading the bulk produce from these trailers have serious inadequacies. While functional, the currently used chain and non-chain driven belt discharge devices are expensive and often problematic, requiring frequent maintenance and replacement. Furthermore, the discharge device also causes damage to the produce. This thesis provides innovative solutions to these two key problems and introduces a completely new trailer design that can be used for both field and road conditions. The main chassis of the trailer has a framework of ribs supported by two I-beams. This unique rib design combined with the main I beams act as large vertebra, which results in a rigid underbody that maintains flexibility and strength. Special consideration was taken while creating this design to account for dynamic loading on soft muddy soils or uneven surfaces while still maintaining the desired lightweight trailer characteristics. In addition to the improved trailer frame and body design, a simple and effective device for unloading bulk products was constructed. The new design-a belt-over-chain system-is actually two separate systems performing one job in unison with different characteristics and speeds. The system works by means of a hydraulic orbit motor that actuates the drive chains into motion. The weight of bulk commodities on the chain presses the unattached conveyor belt against the chain and cross-members, creating friction, which advances the conveyor belt. This thesis solves two of the problems associated with hauling bulk produce from the field to the storage facility and sets the groundwork for improving the hauling capabilities used to move commodities from the field. Finally, this thesis introduces a new commodity self-unloading trailer for hauling produce, which has a belt system that preserves quality and a body design that provides trailer longevity.
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The Study of Superintendent Training and its Effects on Homebuilding Cycle TimeBurk, John Wesley 25 June 2008 (has links) (PDF)
This study was conducted to determine how much time would be saved in the homebuilding cycle when field superintendents received training. The study took place during the 2007 calendar year with a production homebuilder in southern Nevada. New technologies and techniques were introduced during weekly training meetings that were held at both the corporate office and construction job sites. A scheduling tool was introduced along with new procedures and policies. The superintendents were required to report daily on the tasks that had been completed. This gave the superintendent and upper management the ability to follow the home throughout the building process and track the results. Additionally, new policies were created to improve build quality and increase customer satisfaction. This study compared over 300 homes built in 2006 (untrained superintendents) versus nearly 300 homes built in 2007 (trained superintendents). A substantial reduction in cycle time was found when compared to the homes built before the training period, with some projects reducing their average cycle time by over 140 days. Superintendent satisfaction in regards to the training was found to be above average. Through the reduction in cycle time, the company reduced their daily interest costs by nearly 3 million dollars.
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Analysis of Construction-Related Research Compared to Needs of Industry ProfessionalsGraham, Sterling 10 September 2010 (has links) (PDF)
Research plays a large role in the advancement of any industry. It is particularly important that relevant research is performed in an industry as large and critical as the construction industry. A review of literature shows that historically research has not played a major role in the advancement of the construction industry. The work of this thesis was to explore whether there has been a change in this relationship, or not. This thesis explored whether the construction-related research being done is in alignment with the needs of industry. Comparisons of the rankings of construction research and industry views were done to evaluate their correlation to each other. This evaluation was done through a review of literature of four construction research journals. Articles were gathered and classified in common construction themes. Each research theme was given a ranking based on the quantity of articles classified into common construction themes. The research ranking demonstrated that the most popular research theme was training/ human resources, followed by management/ risks and technology/ innovation. A survey was sent to 259 industry professionals asking them to rank the 22 construction themes. A response rate of 14% was achieved through the survey respondents. Survey respondents determine that the most important research theme is constructability, followed by estimating/ bidding and economics/cost control. Findings demonstrate that there was no correlation between the themes that were popularly researched and what is most important to the construction professionals.
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Natural Fibers and Fiberglass: A Technical and Economic ComparisonZsiros, Justin Andrew 11 June 2010 (has links) (PDF)
Natural fibers have received attention in recent years because of their minimal environmental impact, reasonably good properties, and low cost. There is a wide variety of natural fibers suitable for composite applications, the most common of which is flax. Flax has advantages in tensile strength, light weight, and low cost over other natural fibers. As with other natural and synthetic fibers, flax is used to reinforce both thermoset and thermoplastic matrices. When flax is used in thermoplastic matrices, polypropylene and polyethylene are the main resins used. Although at first glance flax may seem to be a cheaper alternative to fiberglass, this may not necessarily be as advantageous as one would hope. A full economic valuation should be based on raw material costs and full processing costs. Although flax fibers used in composites are generally a waste product from linen flax, they require additional processing which can significantly reduce flax's economic advantage over glass. This paper attempts to place some measure of economic comparison coupled with property comparisons between natural (mainly flax) fibers and glass fibers. Our tests compare tensile, flexural, and drop impact properties, as well as heat sensitivity, and colorant acceptance.
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The Use of Building Information Modeling in Generating Hard Bid EstimatesJensen, Peter Samuel 16 December 2010 (has links) (PDF)
Building Information Modeling has provided many benefits to the architectural, engineering, construction and facilities management communities. Many studies have been done to validate the asserted benefits, including benefits to the field of estimating. The studies on estimating are currently limited to the realm of conceptual estimates, and have only treated detailed estimates in the abstract. The purpose of this study was to determine how BIM was being used by companies in a hard bid, or detailed estimate scenario. The research team used the Deseret Towers housing project at Brigham Young University as the basis for the research. A building information model (BIM) was provided to all bidders on the project, and at the conclusion of the bidding process a survey was used to determine how the contractors used the model in their bidding processes. The findings determined that a few of the contractors did use the model for quantity takeoff, and one actually used the quantities as the basis for the submitted bid. Additionally, the survey attempted to determine the prevailing attitudes of the estimators toward BIM as a tool in estimating, and their opinions of the future of BIM in estimating.
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Tool Life of Various Tool Materials When Friction Spot Welding DP980 SteelRidges, Christopher Shane 10 March 2011 (has links) (PDF)
In this study, friction spot welding was used to join DP980 steel sheet. Four different ultra-hard tool materials were used with the objective of determining which tool material produced the highest number of acceptable-strength welds. Three of the tools were composed of various mixtures of polycrystalline cubic Boron Nitride (PCBN), Tungsten, and Rhenium. These materials are referred to herein as Q60, Q70, and Q80, the "Qxx" designation denoting the percentage of the volume of the tool material composed of PCBN. The fourth tool tested was composed entirely of PCBN. The Q70 tool produced approximately 1100 welds of acceptable strength before average weld strength decreased below the acceptable value, and the Q60 tool produced approximately 600 welds of acceptable strength. The Q80 material did not produce any welds with strengths above the acceptable value. However, Q80 produced the greatest number of welds of consistent strength. The PCBN tool, being the hardest, also did not produce any welds of acceptable strength, and failed at 257 welds. This failure is presumed to be a result of a tool/parameter mismatch which caused excessive loads on the tool. This research revealed that the weld parameters and tool materials used in this study will not generally provide for feasibility of implementation in industry. Further advances in weld parameter selection, tool geometry, and tool materials will be necessary in order to make friction spot joining of high strength steels an economically viable option.
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