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This research study focuses on evaluating the design of HSC prestressed bridge girders. Specifically there were three major objectives. First, to determine the current state of practice for the design of HSC prestressed bridge girders. Second, to evaluate the controlling limit states for the design of HSC prestressed bridge girders and identify areas where some economy in design may be gained. Third, to conduct a preliminary assessment of the impact of raising critical design criteria with an objective of increasing the economy and potential span length of HSC prestressed girders. The first objective was accomplished through a literature search and survey. The literature search included review of design criteria for both the AASHTO Standard and LRFD Specifications. Review of relevant case studies of the performance of HSC prestressed b...
Quantifying the drilling or recompletion potential in producing gas basins is often a challenging problem, because of large variability in rock quality, well spacing, and well completion practices, and the large number of wells involved. Complete integrated reservoir studies to determine infill potential are often too time-consuming and costly for many producing gas basins. In this work we evaluate the accuracy of a statistical moving-window technique that has been used in tight-gas formations to assess infill and recompletion potential. The primary advantages of the technique are its speed and its reliance upon well location and production data only. We used the statistical method to analyze simulated low-permeability, 100-well production data sets, then compared the moving-window infill-well predictions to those from reservoir ...
Pavements are a major part of the infrastructure in the United States. Moisture damage of these pavements is a significant problem. To predict and prevent this kind of moisture damage a great deal of research has been performed on this issue in past. This study validates an analytical approach based on surface energy aimed at assessing moisture damage. Two types of bitumen and three aggregates are evaluated in the study. The two types of bitumen represent very different chemical extremes and the three aggregates (a limestone, siliceous gravel, and granite) represent a considerable range in mineralogy. Moisture damage was monitered as a change in dynamic modulus with load cycles. The analysis demonstrates the need to consider mixture compliance as well as bond energy in order to predict moisture damage. Mixtures with the ...
To make sound investment decisions, decision makers need accurate estimates of the uncertainties present in forecasts of reservoir performance. In this work I propose a method, the integrated mismatch method, that incorporates the misfit in the history match into the estimation of uncertainty in the prediction. I applied the integrated mismatch method, which overcomes some deficiencies of existing methods, to uncertainty estimation in two reservoir studies and compared results to estimations from existing methods. The integrated mismatch method tends to generate smaller ranges of uncertainty than many existing methods. When starting from nonoptimal reservoir models, in some cases the integrated mismatch method is able to bracket the true reserves value while other methods fail to bracket it. The results show that even starting from a ...
The goal of this study was to examine the impact of Africanization on the genetic structure of the Welder Wildlife Refuge feral honey bee population by scoring mtDNA and microsatellite polymorphisms. Adult honey bee workers, collected between 1991 and 2001, were screened for mtDNA using the cytochrome b/BglII, ls rRNA/EcoRI, and COI/HinfI PCR-based assays. The procedure allowed identification of four mitotypes: eastern European, western European, A. m. lamarckii, and A. m. scutellata. The relative frequencies of the four mitotypes changed radically during the 11-year period. Prior to immigration of Africanized honey bees, the resident population was essentially of eastern European maternal ancestry. The first colony of A. m. scutellata mitotype was detected in 1993. Between 1995 and 1996 there was a mitotype turnover in the populati...
Sorghum (Sorghum bicolor [L.] Moench) is fifth among the major cereal crops in the world in terms of production area and total production. Grain sorghum can be successfully produced in a wide range of environments, its productivity is severely limited by pathogens, insects and abiotic stresses. One of these pathogens is Claviceps africana Frederickson Mantle & de Milliano, commonly known as ergot. As is the case with many sorghum diseases, the best long term approach to control ergot may be the use of genetic resistance. There is limited information about resistance to C. africana in sorghum, and the reported resistance in most lines is fertility-based. Dahlberg (1999) first reported the line IS8525 to have the most tolerance to ergot of any of the accessions screened in Puerto Rico. The specific objectives of this research are: (1)...
The main objectives of this research are (a) to investigate the thermal effect of double skin facades in office buildings in hot climates and (b) to propose guidelines for their efficient design based on this evaluation. The study involves the energy performance analysis of two buildings in India. A base case with the existing building skin was simulated for both the cities. The main source for the high cooling loads was found to be heat gain through windows and walls. This led to the evolution of a series of facade strategies with the goals of reducing heat gain, providing ventilation and day-lighting. The buildings were then simulated for their energy performance with the proposed double-skin strategies. Each of these strategies was varied according to the layers constituting the facade, the transparency of the facade and the orienta...
The Jacob field was discovered in the year 1931. In the year 2002, due to the low productivity of the field, the company wanted to determine whether to keep operating, abandon or sell the field. So they asked Texas A&M University to perform the study, determine the oil potential, and make recommendations to improve production. Since no previous reservoir study was performed in this field, the original oil in place and the current status of depletion was unknown. Therefore a complete integrated study was needed in order to learn about the reservoir and evaluate it in a qualitative and quantitative manner, before making any recommendation. The current pay zone underlying the Jacob field forms a monocline structure composed of unconsolidated young clastic sediments deposited in the Eocene epoch of the stratigraphic column of the Nueces ...
This study evaluated the applicability of remote sensing instrumentation for site- specific management of abiotic and biotic stress on cotton grown under a center pivot. Three different irrigation regimes (100%, 75%, and 50% ETc) were imposed on a cotton field to 1) monitor canopy temperatures of cotton with infrared thermometers (IRTs) in order to pinpoint areas of biotic and abiotic stress, 2) compare aerial infrared photography to IRTs mounted on center pivots to correlate areas of biotic and abiotic stress, and 3) relate yield to canopy temperatures. Pivot-mounted IRTs and IR camera were able to differentiate water stress between the irrigation regimes, however, only the IR camera was effectively able to distinguish between biotic (cotton root rot) and abiotic (drought) stress with the assistance of groundtruthing. The 5...
The purpose of this study was to explore the relationships between career resilience and career beliefs among employees in Taiwan. This study also examined whether selected demographic variables had effects on career resilience and career beliefs. A pilot study involving 178 participants was conducted in Taiwan to validate the instruments used in the main study. Twenty items were selected for measuring career resilience. These items were taken from London's Career Motivation Inventory (1993b), Noe, R. A., Noe, A. W., and Bachhuber's measures of career motivation (1990), and Michigan's Career Resilience Scale (Bice, 1999, January 24-30). Forty-nine items consisting of 10 subscales in the Career Beliefs Scale were adopted from Yang's Chinese Career Beliefs Inventory-Form B (1996). The study had 578 current employees from diverse wo...
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