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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.
141

The Use of Evidence-Based Design in Hospital Renovation Projects

Whitaker, David S. 01 March 2018 (has links)
Since the 1960s, researchers have been exploring how the design of the built environment impacts the health and well-being of occupants and users. By the 1980s, further research began to focus on healthcare facilities in particular and how design could influence patient healing and medical staff performance (Alfonsi, 2014). Evidence-Based Design (EBD) is "the process of basing decisions about the built environment on credible research to achieve the best possible outcomes" (CHD, 2016). The desired outcomes of Evidence-Based Design recommendations include improvements in the following: patient healing, patient experience and comfort, medical staff performance, and medical staff job satisfaction (CHD, 2017). Extensive research has been done on the subject of EBD; however, the question remains whether or not the latest research findings are being utilized by the design and construction industries in practice. The purpose of this research is to determine whether or not the latest scientific knowledge and research findings are being implemented into hospital renovation projects by the healthcare design and construction industries. A list of recommendations from existing EBD literature was compiled. Construction documents from 30 recent healthcare facility renovation projects across the United States were then obtained and analyzed. The findings indicate that EBD recommendations are being adopted in practice at consistently high levels. These findings also reveal that there are still areas of potential improvement which could inform those who influence or determine building and design codes, standards, and guidelines. The results are instructive to owners, designers, and contractors by providing a glimpse into how well the industry is recognizing and implementing known best practices. The findings likewise open up new opportunities for further research which could lead to additional improvement in the healthcare facilities of the future.
142

Crack Healing in 304L Stainless Steel Using Additive Manufacturing and Friction Stir Processing (FSP)

Gygi, Cameron Scott 01 August 2017 (has links)
Continuing an investigation on using FSP to heal stress corrosion cracks (SCC) in welds on nuclear reactors, this study seeks to use AM in addition to FSP to aid crack repair. Previous studies address that current repair technology on nuclear reactors involves the use of TIG welding which can allow helium atoms to aggregate and form voids at the grain boundaries. This weakens the material and renders the repair ineffective. Another previous study evaluated the effectiveness of FSP alone in repairing SCC which did have defects depending on the parameters used during FSP. This study evaluated the use of AM in addition to FSP. Literature is available on FSP and AM separately and literature is available on technologies that used both them together. However, the current processes that are available that use both AM and FSP can be expensive and may be impractical for some purposes. This study shows a new process that is both less expensive and more practical in SCC repair. Initial proof of concept trials was performed on 1018 mild steel using both wire fed additive and insert additive technologies. A slot would be removed and filled in with an additive process and processed using FSP. Because of poor repeatability, substantial distortion, and voids present this study went forward using insert technologies in further experiments rather than wire wed additive technologies. In addition, the depth and width of the insert or area where the added material would be placed was varied in initial trails. Tensile testing was performed on initial steel trials and the stainless steel experiments and it demonstrated a correlation between depth of the added material and the tensile strength. Micro-hardness mapping performed on initial steel trials also showed hardening in the FSP stir zone. Three-point bend tests were performed to show that an existing crack underneath the FSP zone would not propagate through the nugget. All evaluations supported a substantial increase in yield strength increased after FSP.
143

Friction Bit Joining of Dissimilar Combinations of GADP 1180 Steel and AA 7085 – T76 Aluminum

Atwood, Lorne Steele 01 June 2016 (has links)
Friction Bit Joining (FBJ) is a method used to join lightweight metals to advanced high-strength steels (AHSS). The automotive industry is experiencing pressure to improve fuel efficiency in their vehicles. The use of AHSS and aluminum will reduce vehicle weight which will assist in reducing fuel consumption. Previous research achieved joint strengths well above that which was required in three out of the four standard joint strength tests using DP980 AHSS and 7075 aluminum. The joints were mechanically tested and passed the lap-shear tension, cross-tension, and fatigue cycling tests. The t-peel test configuration never passed the minimum requirements. The purpose of continuing research was to increase the joint strength using FBJ to join the aluminum and AHSS the automotive industry desires to use specifically in the t-peel test. In this study FBJ was used to join 7085 aluminum and GADP1180 AHSS. The galvanic coating on the AHSS and its increased strength with the different aluminum alloy required that all the tests be re-evaluated and proven to pass the standard tests. FBJ is a two-step process that uses a consumable bit. In the first step the welding machine spins the bit to cut through the aluminum, and the second step applies pressure to the bit as it comes in contact with the AHSS to create a friction weld.
144

An Investigation of the Impact A ROV Competition Curriculum has on Student Interest in sTEm, Specifically Technology and Engineering

Bates, Daniel Gordon 01 June 2016 (has links)
This research investigates the impact a Remotely Operated Vehicle (ROV) program has on student interest in, and perception of, technology and engineering (sTEm). ROV programs embed areas of science, technology, engineering and math (STEM) into their curriculum; however, emphasis for this study is placed on interest and perception of the "T" and "E" of STEM. Although there are many articles detailing the benefits of ROV programs, there is little empirical data documenting the impact on student interest and perception of sTEm. This study outlines the background of a few major ROV programs in the U.S.; specifically Utah Underwater Robotics (UUR), an ROV statewide program within a landlocked state, the methods for gathering data and findings from a sTEm survey instrument administered to over 300 students ranging from 6th to 12th grade who participated in a five-month ROV program and near 50 students who did not. Key findings include: 1. Males were more interested in technology and engineering than females, regardless of whether they participated in the UUR ROV program. 2. Male and female students in the UUR program were more interested and had a more positive perception of engineering than those who did not participate in the UUR ROV program. 3. Females in the UUR program reported more interest in engineering careers and activities than females not in the program. 4. Females in the program reported more interest and self-efficacy in science than females not in the program. 5. Males in the UUR program reported more awareness of the positive and negative consequences of technology and engineering than those who did not participate.
145

Computing Research in Academia: Classifications, Keywords, Perceptions, and Connections

Kim, Sung Han 01 May 2016 (has links)
The Association for Computing Machinery (ACM) recognizes five computing disciplines: Computer Science (CS), Computer Engineering (CE), Information Technology (IT), Information Systems (IS), and Software Engineering (SE). Founded in 1947 the ACM is the world's largest society for computing educators, researchers, and professionals. While Computer Science has been a degree program since 1962, the other four are relatively new. This research focuses on understanding the graduate research in four of the five ACM disciplines (CS, CE, IT, and IS) using a large body of thesis and dissertation metadata. SE is not found in the metadata and graduate work in SE is not included. IS is no longer officially found in the metadata so its representative ProQuest replacement, Information Science although not an ACM recognized discipline is used based on the commonality of the associated ProQuest Classification code. The research is performed using co-word and graph analysis of author-supplied Classifications, Departments, and keywords. Similarities and differences between the disciplines are identified. Whether the computing discipline is the primary or the secondary focus of the research makes a large difference in the connections it makes with other academic disciplines. It was found that the Departments from which computing research originates varies widely but the majority come from computing-related Departments. Finally, gaps are apparent from the practitioners' views of the computing disciplines versus the public's view.
146

DEFORMATION-BASED EXCAVATION SUPPORT SYSTEM DESIGN METHOD

Intsiful, Sekyi K 01 January 2015 (has links)
Development in urban areas around the world has steadily increased in recent years. This rapid development has not been matched by the ever decreasing open space commonly associated with urban centers. Vertical construction, thus, lends itself a very useful solution to this problem. Deep excavation is often required for urban construction. Unfortunately, the ground movements associated with deep excavation can result in damage to adjacent buildings. Thus, it is critically important to accurately predict the damage potential of nearby deep excavations and designing adequate support systems. A new design method is proposed, as an attempt, to address the problem. The method is semi-empirical and directly links excavation-induced distortions experienced by nearby buildings and the components of the excavation support system. Unlike, the traditional limit equilibrium approach, the method is driven by the distortions in adjacent buildings. It goes further to propose a preliminary cost chart to help designers during the design phase. The benefit is that initial cost is known real time and will help speed up making business decisions. A new design flowchart is proposed to guide the designer through a step-by-step procedure. The method is validated using 2D Plaxis (the finite element program) simulation. Though the nature of deep excavation is three-dimensional, a plane strain condition is valid when the length of the excavation is long. Hence, two-dimensional finite element simulation was considered appropriate for this effort. Five hypothetical cases were compared and the model performed very well. The lack of available literature on this approach made verification difficult. It is hoped that future case histories will be used to ascertain the veracity of the deformation-based design method.
147

Bridge Deck Cracking Investigation and Repair

Vargas, Vidal Velez 01 January 2012 (has links)
The focus of this study is to investigate the cracking of concrete bridge decks and the sealants used in repairing transverse cracks. Cracking could occur in both hardened mature concrete and early age concrete. Several factors affect concrete cracking, such as age-dependent material properties, thermal- and moisture-related stresses and strains, material viscoelastic behavior, restraints, concrete expansion and contraction, casting sequence, formwork, material characteristics, and environmental exposure. The causes of early age cracking are primarily attributed to effects such as plastic shrinkage, temperature effects, autogenous shrinkage, and drying shrinkage. This deck cracking could greatly reduce durability, lead to a loss of functionality, loss of stiffness, and ultimately the loss of structural safety. The study investigates the deck cracking in general and also the transverse cracks developed in hardened concrete at early ages before service loads application. Both experimental and analytical investigations were performed. The experimental study included testing of 9 reinforced concrete slab specimens (18”x 48”x 5.5”). Cracks were induced in the slabs with different crack widths and lengths, sealed with 4 different materials of sealants, and tested under static loading. The study also included tensile testing of dry hardened samples of sealants. In addition, field application was performed on a bridge, where transverse deck cracks were sealed using 4 different sealant materials; cores were taken and tested according to ASTM-C496. The results of the testing showed that the 3-part HMWM was the best performing sealer for cracks between 0.01 and 0.019 inches of width with the epoxy sealer performing the best for cracks wider than 0.02 inches.
148

Driver Behavior Evaluation of Variable Speed Limits and a Conceptual Framework for Optimal VSL Location Identification

Harrington, Curt P 18 March 2015 (has links)
Static speed limits are the norm across the world’s roadway networks. However, advances in technology and increased applications in intelligent transportation systems (ITS) provide a mechanism for upgrading traditional speed limits into an active traffic management system. More specifically, variable speed limits (VSLs) can be used in high crash severity locations and in real-time congestion and weather events to increase traffic safety and operations. Much of the available literature on VSLs focuses upon crash prediction algorithms for VSLs, simulations, and effectiveness of real-world VSL implementations. One noticeable gap in the existing literature is related to driver compliance under varied configurations of alerting drivers of the variable speeds. An additional gap in literature is related to existence of a conceptual framework for identifying optimal corridors for potential VSL implementation. Within this thesis drivers’ willingness to comply with VSLs was investigated via focus groups and static surveys during the experimental process. Connections are made between driver speed choice and type of speed limit condition including uniform speed vi limit (USL) versus VSL, overhead mount versus side mount, presence of an explanatory message, and the numerical speed limit value. An analysis of the survey results was completed to isolate critical factors in VSL compliance. Opinions and perspectives on VSLs are derived through the focus group sessions Lastly, a case study approach is presented in which a region is chosen, and implementation metrics are analyzed on the major roadway networks using a GIS platform to create a composite ranking system for potential optimal VSL corridors. The study aims to be used as a foundation to justify use of certain types of VSLs in addition to creating a conceptual framework for VSL implementation zone identification.
149

Multidimensional Highway Construction Cost Indexes Using Dynamic Item Basket

Shrestha, Joseph, Jeong, H. David, Gransberg, Douglas D. 01 August 2017 (has links)
A highway construction cost index (HCCI) is an indicator of the purchasing power of a highway agency. Thus, it must reflect the actual construction market conditions. However, current methods used by most state departments of transportation are not robust enough to meet this primary goal due to (1) a significantly insufficient sample size of bid items used in HCCI calculation; and (2) inability to address the need to track highway construction market conditions in specific submarket segments such as, but not limited to, various project types, sizes, and locations. This study proposes an advanced methodology to overcome these apparent limitations using two new concepts: (1) dynamic item basket; and (2) multidimensional HCCIs. The dynamic item basket process identifies and utilizes an optimum amount of bid-item data to calculate HCCIs in order to minimize the potential error due to a small sample size, which leads to a better reflection of the current market conditions. Multidimensional HCCIs dissect the state highway construction market into distinctively smaller sectors of interest and thus, allow state Departments of Transportation to understand the market conditions with much higher granularity. A framework is developed to integrate these two concepts and a standalone prototype system, named the Dyna-Mu-HCCI System, is developed to automate the data-processing part of the framework. The historical bid data of the Montana Department of Transportation are used to evaluate the performance of the Dyna-Mu-HCCI System and measure the effects of the dynamic item basket (DIB) and multidimensional HCCIs. The results show an eightfold increase in terms of the number of bid items used in calculating HCCIs and at least a 20% increase in terms of the total cost of bid items used. In addition, the multidimensional HCCIs reveal different cost-change patterns from different highway sectors. For example, the bridge construction market historically shows a very different trend compared with the overall highway construction market. The new methodology is expected to aid state Departments of Transportation in making more-reliable decisions in preparing business plans and budgets with more accurate and detailed information about the construction market conditions. Further, the prototype Dyna-Mu-HCCI System is expected to significantly facilitate the HCCI calculation process and rapidly implement this new system.
150

Factors Associated with Crash Severities in Built-up Areas Along Rural Highways of Nevada: A Case Study of 11 Towns

Shrestha, Pramen P., Shrestha, Joseph 01 February 2017 (has links)
In 2014, 32,675 deaths were recorded in vehicle crashes within the United States. Out of these, 51% of the fatalities occurred in rural highways compared to 49% in urban highways. No specific crash data are available for the built-up areas along rural highways. Due to high fatalities in rural highways, it is important to identify the factors that cause the vehicle crashes. The main objective of this study is to determine the factors associated with severities of crashes that occurred in built-up areas along the rural highways of Nevada. Those factors could aid in making informed decisions while setting up speed zones in these built-up areas. Using descriptive statistics and binary logistic regression model, 337 crashes that occurred in 11 towns along the rural highways from 2002 to 2010 were analyzed. The results showed that more crashes occurred during favorable driving conditions, e.g., 87% crashes on dry roads and 70% crashes in clear weather. The binary logistic regression model showed that crashes occurred from midnight until 4 a.m. were 58.3% likely to be injury crashes rather than property damage only crashes, when other factors were kept at their mean values. Crashes on weekdays were three times more likely to be injury crashes than that occurred on weekends. When other factors were kept at their mean value, crashes involving motorcycles had an 80.2% probability of being injury crashes. Speeding was found to be 17 times more responsible for injury crashes than mechanical defects of the vehicle. As a result of this study, the Nevada Department of Transportation now can take various steps to improve public safety, including steps to reduce speeding and encourage the use of helmets for motorcycle riders.

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