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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.
1

Repair versus replace, a second look : the windows of the tower at the University of Texas at Austin

Freeman, Emily Paige, 1984- 02 November 2010 (has links)
The Secretary of the Interior’s Standards for the Treatment of Historic Buildings promote repair rather than replacement of deteriorated features when possible. Though replacement and retrofitted elements may provide improved energy efficiency with a minor impact on appearance, there is currently no guide for objectively considering the potential benefits of such treatments for historic buildings. In an effort to provide decision-making tools to those seeking to balance both preservation and economic/ sustainability concerns, this thesis will present an approach to weighing treatment options specifically for windows, including modifications for energy efficiency that are not specifically endorsed by the Secretary of the Interior’s Standards. This thesis explores the critical decision processes involved in selecting to repair or replace deteriorated historic windows, and examines those of the Main Building Tower of the University of Texas as a case study. The steel windows of the Tower, which was completed in 1937, suffer from corrosion and are not performing optimally in terms of energy efficiency. An understanding of the history and significance of the building, the current condition and performance of the windows, balanced against project-specific goals and an evaluation of current treatment options for historic windows helped narrow the potential options for the Tower. Including a “decision tree” that assists users in selecting an appropriate treatment, this thesis maps the considerations necessary to arrive at an informed solution, which may be applied to other projects with varying existing conditions and project objectives. / text
2

A New Technique: Replace Algorithm To Retrieve A Version From A Repository Instead Of Delta Application

Otlu, Suleyman Onur 01 April 2004 (has links) (PDF)
The thesis introduces a new technique that is an alternative method instead of applying deltas to literal file sequentially to retrieve a version from a repository. To my best knowledge / this is the first investigation about delta combination for copy/insert instruction type with many experimental results and conclusions. The thesis proves that the delta combination eliminates unnecessary I/O process for intermediate versions when delta application is considered, therefore reduces I/O time. Deltas are applied to literal sequentially to generate the required version in the classical way. Replace algorithm combines delta files which would be applied in delta application as combined delta, and applies it to literal to generate the required one. Apply runs in O (size (D)) time where D is the destination file and size (D) is its size. To retrieve nth version in a chain where 1st version is literal, it requires n-1 time apply. Replace algorithm runs in O (i + c * log2 n) time where i is the total length of all inserts, c is the total length of all copies in destination delta, and n is the number of instructions in source delta. To retrieve the same nth version, it requires n-2 time replace and one apply.
3

Forest Carbon Dynamic – Positive and Negative perspectives on the use of Biomass Energy to replace Fossil Fuel

Lundmark, Kennia January 2018 (has links)
From 1970 to 2010, circa 78% of the Greenhouse gases emissions came from the emissions of CO2 derived from industrial processes and fossil fuel combustion. The fossil energy resources (coal, oil and natural gas) increase the concentration of carbon dioxide in the atmosphere causing diverse changes related to global warming. Despite policies adopted to mitigate the climate change, global warming is not decreased. This literature review will analyze and investigate the use of forest biomass to replace fossil fuel energy and how it can affect climate change. This study used secondary data to identify the main perspectives in the use of forest biomass to produce energy. The policies at the global, regional and national level are also described. How the national level is influenced by the international and regional level and how the policies match with the current knowledge on the theme. The results showed that the use of forest biomass was better to replace coal than natural gas or oil, due to the payback time. The use of old-growth forests or natural forest increases the time to the released emissions to be offset. Residues showed to have faster payback time than other forest biomass, as well as, the use of this biomass avoid cut down trees. However, the use of residues can cause serious impacts, as biodiversity loss. The conclusion was that the use of biomass will increase the CO2 emissions, whether all emissions are included. Despite the payback time is faster to forest biomass than fossil fuel, biomass is not a good alternative to replace fossil fuel energy. Because of the combustion efficiency of biomass is less than fossil fuel to produce the same amount the energy. Regarding the policies, there are contradictions between the international and regional level about the use of forests. As also, regional level has contradictions in their criteria that should be avoided. If the forest biomass has to be use, this study recommended the use of residues. / <p>20180619</p>
4

Fish intestinal cultures for ecotoxicological studies : in vitro and primary culture models

Langan, Laura January 2017 (has links)
Ecotoxicity testing of chemicals for environmental risk assessment is an area where a high number of vertebrates are used across a variety of industrial sectors. The application of the 3Rs in toxicity testing using fish address both the ethical and societal concerns around this issue in addition to the increasing legislative requests for the incorporation of animal alternatives. This thesis aims to highlight the potential of 3D cell culture models to "bridge the gap" between in vitro and in vivo screening procedures for testing of chemicals with the potential to persist or bioaccumulate thereby improving the predictive power of screening procedures. This thesis examines two alternative methods for their potential use as an intestinal based toxicokinetic tool for environmental risk assessment, utilising an in vitro fish cell line replacement tool (RTgutGC). In addition, for the first time a new intestinal primary cell culture based model was developed to address both intestine region specific response (pyloric, anterior, mid and posterior) and size related adaptability to toxins. Paramagnetic oximetry was used to measure oxygen content within 3D structures (spheroids) in order to better understand the microenvironment of these culture models. Using histology, immunohistochemistry, transepithelial electrical resistance (TEER), transmission electron microscopy (TEM), metabolic, fluorescence and gene expression assays, the comparability of this system to native intestinal response was established. Following exposure to carefully chosen environmental contaminants (Benzo[a]pyrene and Copper), the RTgutGC cell line demonstrated comparable responses to existing literature in terms of uptake, metabolism, DNA damage and the presence an equivalent saturable level. Primary enterocytes cultured on transwell inserts remained viable for upto six weeks, with permeability and metabolic activity comparable to native tissue (both in vitro and ex vivo). Taken in combination, these features of enterocytes represent a profile more closely representative of the intestine then the widely used "gut sac" method. With the potential advantages of incorporating complexity at differing levels (connective tissue layer, intestinal bacteria biome), the intestinal models described offer the potential to screen highly persistent toxins which may require prolonged incubation, in addition to the exploration of complex experimental designs which minimise animal usage (uptake, depuration, uptake). As a consequence, the models developed within this thesis significantly enrich the emerging fish based in vitro testing strategies.
5

Effect of Soil Replacement Option on Surface Deflections for Expansive Clay Profiles

January 2013 (has links)
abstract: Urbanization and infrastructure development often brings dramatic changes in the surface and groundwater regimes. These changes in moisture content may be particularly problematic when subsurface soils are moisture sensitive such as expansive soils. Residential foundations such as slab-on ground may be built on unsaturated expansive soils and therefore have to resist the deformations associated with change in moisture content (matric suction) in the soil. The problem is more pronounced in arid and semi arid regions with drying periods followed by wet season resulting in large changes in soil suction. Moisture content change causes volume change in expansive soil which causes serious damage to the structures. In order to mitigate these ill effects various mitigation are adopted. The most commonly adopted method in the US is the removal and replacement of upper soils in the profile. The remove and replace method, although heavily used, is not well understood with regard to its impact on the depth of soil wetting or near-surface differential soil movements. In this study the effectiveness of the remove and replace method is studied. A parametric study is done with various removal and replacement materials used and analyzed to obtain the optimal replacement depths and best material. The depth of wetting and heave caused in expansive soil profile under climatic conditions and common irrigation scenarios are studied for arid regions. Soil suction changes and associated soil deformations are analyzed using finite element codes for unsaturated flow and stress/deformation, SVFlux and SVSolid, respectively. The effectiveness and fundamental mechanisms at play in mitigation of expansive soils for remove and replace methods are studied, and include (1) its role in reducing the depth and degree of wetting, and (2) its effect in reducing the overall heave potential, and (3) the effectiveness of this method in pushing the seat of movement deeper within the soil profile to reduce differential soil surface movements. Various non-expansive replacement layers and different surface flux boundary conditions are analyzed, and the concept of optimal depth and soil is introduced. General observations are made concerning the efficacy of remove and replace as a mitigation method. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2013
6

Statistical Inference for Costs and Incremental Cost-Effectiveness Ratios with Censored Data

Chen, Shuai 2012 May 1900 (has links)
Cost-effectiveness analysis is widely conducted in the economic evaluation of new treatment options. In many clinical and observational studies of costs, data are often censored. Censoring brings challenges to both medical cost estimation and cost-effectiveness analysis. Although methods have been proposed for estimating the mean costs with censored data, they are often derived from theory and it is not always easy to understand how these methods work. We provide an alternative method for estimating the mean cost more efficiently based on a replace-from-the-right algorithm, and show that this estimator is equivalent to an existing estimator based on the inverse probability weighting principle and semiparametric efficiency theory. Therefore, we provide an intuitive explanation to a theoretically derived mean cost estimator. In many applications, it is also important to estimate the survival function of costs. We propose a generalized redistribute-to-the right algorithm for estimating the survival function of costs with censored data, and show that it is equivalent to a simple weighted survival estimator of costs based on inverse probability weighting techniques. Motivated by this redistribute-to-the-right principle, we also develop a more efficient survival estimator for costs, which has the desirable property of being monotone, and more efficient, although not always consistent. We conduct simulation to compare our method with some existing survival estimators for costs, and find the bias seems quite small. Thus, it may be considered as a candidate for survival estimator for costs in a real setting when the censoring is heavy and cost history information is available. Finally, we consider one special situation in conducting cost-effectiveness analysis, when the terminating events for survival time and costs are different. Traditional methods for statistical inference cannot deal with such data. We propose a new method for deriving the confidence interval for the incremental cost-effectiveness ratio under this situation, based on counting process and the general theory for missing data process. The simulation studies show that our method performs very well for some practical settings. Our proposed method has a great potential of being applied to a real setting when different terminating events exist for survival time and costs.
7

Longevity of Crown Margin Repairs Using Glass Ionomer: A Retrospective Study

Watson, Justin I. January 2020 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Objectives: Repair of crown margins may extend the functional life of existing crowns. However, the longevity of such treatment is unknown. This study determined the survival time of crown margin repairs (CMR) with glass-ionomer (GI) and resin-modified glass-ionomer cements. Methods: We queried axiUm (Exan Group, Coquitlam, BC, Canada) database for permanent teeth that underwent CMR in the Graduate Operative Dentistry Clinic, Indiana University School of Dentistry (IUSD), Indianapolis, Ind., USA, from January 1, 2006 through January 1, 2018. Since there is no CDT code for the CMR procedure, CDT codes for resin-composite and GI restorations (D23XX) were queried; these patients also had treatment notes that indicated CMR. The final data set included patient ID, birth date, gender, dates of treatments, CDT codes, tooth type, tooth surface and existing findings. Two examiners developed guidelines for record review and manually reviewed the clinical notes of patient records to confirm CMR. Only records that were confirmed with the presence of CMR were retained in the final dataset for survival analysis. Survival time was calculated by Kaplan-Meier statistics and a Cox Proportional Hazards model was performed to assess the influence of selected variables (p < 0.05). Results: 214 teeth (115 patients) with CMR were evaluated. Patient average age was 69.4  11.7 years old. Posterior teeth accounted for 78.5 percent (n = 168) of teeth treated. CMRs using GI had a projected 5-year survival rate of 62.9 percent (K-M Analysis) and an 8.9 percent annual failure rate. Cox Proportional Hazards Regression analysis revealed that none of the factors examined (age, gender, tooth type) affected time to failure. Conclusion: CMRs may extend the longevity of crowns with defective margins. Larger EHR studies or case control studies are needed to investigate other variables, such as the caries risk status or the severity of defects that may affect the survival rate of CMRs.
8

Replacement of Lead in a Norma Precision AB Hunting Bullet

Petersson, Christopher, Klara, Trydell January 2017 (has links)
No description available.
9

srcDiff: Syntactic Differencing to Support Software Maintenance and Evolution

Decker, Michael John 24 July 2017 (has links)
No description available.
10

Logical specification of finite-state transductions for natural language processing

Vaillette, Nathan 04 February 2004 (has links)
No description available.

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