Browsing by Subject "temperature"
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Item A new sensor concept for simultaneous measurement of pressure, temperature and thickness of plate structures using modified wave propagation theory(Texas A&M University, 2005-11-01) Lo, Tzu-WeiThis thesis presents a multi-purpose sensor concept viable for the simultaneous measurement of pressure, temperature and thickness of plate structures. It also establishes the knowledge base necessary for future sensor design. Thermal-Acousto Photonic Non-Destructive Evaluation (TAP-NDE) is employed to remotely initiate and acquire interrogating ultrasonic waves. Parameters including pressure, temperature and plate thickness are determined through exploring the dispersion features of the interrogating waves. A theoretical study is performed, through which a modified wave propagation theory applicable to homogeneous, isotropic, linear elastic materials is formulated along with an associated numerical model. A numerical scheme for solving the model is also developed using FEMLAB, a finite element based PDE solver. Gabor Wavelet Transform (GWT) is employed to map numerical time waveforms into the joint time-frequency domain. Wave time-frequency information enables dispersion curves to be extracted and material pressure, temperature and thickness to be determined. A sensor configuration design integrating the wave generation and sensing components of the proven TAP-NDE technology is also developed. Conclusions of the research are drawn from wave dispersion obtained corresponding to the following ranges of parameters: 300-500kHz for frequency, 25-300oC for temperature, 1-3mm for plate thickness, and 6 10 1?? - 7 1 10 ?? N/m for pressure. Each of the three parameters considered in the study has a different level of impact on plate wave dispersion. Plate thickness is found to have the most impact on wave dispersion, followed by temperature of the plate. The effect attributable to pressure is the least prominent among the three parameters considered. Plate thickness and temperature can be readily measured while simultaneously resolved using dispersion curves. However, pressure variation can only be differentiated when the plate is smaller than 1mm in thickness. It is observed that the thicker the plate, the faster the frequency group velocity. Also, the group velocities of all frequency components considered are seen to increase with increasing temperature, but decrease with increasing pressure.Item A Novel Model for Fracture Acidizing with Important Thermal Effects(2013-12-05) Lyons, JohnFracture acidizing is a well stimulation technique used to improve the productivity of low-permeability reservoirs, and to bypass deep formation damage. The reaction of injected acid with the rock matrix forms etched channels (that depend on injection rate, mass transport properties, formation mineralogy, reaction chemistry of the acid, and temperature) through which oil and gas can then flow upon production. The use of a model that can effectively describe fracture acidizing is an essential step in designing an efficient and economical treatment. Several studies have been conducted on modeling fracture acidizing, however, most of these studies have not accounted for the effect of variation in acid temperature (by heat exchange with the formation and the heat generated by acid reaction with the rock) on reaction rate and mass transfer of acid inside the fracture. In this study, a new fracture acidizing model is presented that uses the lattice Boltzmann method for fluid transport and takes into account these temperature effects. The lattice Boltzmann method incorporates both accurate hydrodynamics and reaction kinetics at the solid-liquid interface. This method is also well known for its capability to handle re- active transport in complex geometries. This enables the method to model realistic fracture shapes, on a pore-scale level, and predict the shape of the fracture after acidizing. Results of carbonate fracture dissolution with and without the thermal effects are presented. It is found that including thermal effects alters the predicted shape of the fracture after acidizing.Item Algal biofuels : the effect of temperature on algal growth and lipid content(2009-08) Klenzendorf, Stephanie Marie; Marshall, Jill Ann; Mehdy, Mona Cynthia, 1955-; Sathasivan, KanagasabapathiReplacing fossil fuels with algae, a renewable resource, is an exciting possibility. This study evaluates the algae found in South Texas brackish water ponds used for aquaculture of fish as a possible source of biofuels. Samples of algae from these ponds were cultured at varying temperatures ranging from 15.5ºC to 36.5ºC. High levels of growth were observed at 20.5ºC and the highest lipid content was measured at 23.0ºC. Temperature was also a factor in the distribution of microalgal taxa throughout the temperature gradient. This information will be added to the growing body of research investigating similar cultures of algae for future biofuel production.Item An Improved Model for Sandstone Acidizing and Study of the Effect of Mineralogy and Temperature on Sandstone Acidizing Treatments and Simulation(2013-01-14) Agarwal, Amit KumarSandstone acidizing is a complex operation because the acidizing fluid reacts with a variety of minerals present in the formation that results in a wide range of reaction products. The hydrofluoric acid (HF) reaction rate differs widely from mineral to mineral because of the variation in the reaction rate and the area of contact with the injected fluid. The series of reactions occurring in sandstone makes it all the more difficult to find the exact individual reaction rate constants. An improved model that provides better estimates of the outcome of a sandstone acidizing treatment is developed following a review of previous sandstone acidizing models. The model follows the lumped mineral methodology and is based mainly on the kinetic approach. The use of accurate reaction-rate laws allows the model to effectively predict the consumption of acidizing fluid during the stimulation treatment. The consideration of a proper equation for the silica gel filming factor accounts for the fact that some clay becomes inaccessible to the acid when silica gel precipitates on their surface. The proposed model is shown here to be valid in extrapolating laboratory coreflood data and predicting the effluent acid concentration at various flow rates. The damage during sandstone acidizing can be minimized when stimulation treatments are designed according to the percentage of carbonate in the formation, type and amount of clay in the formation and the reservoir bottomhole temperature. Most of the available software for design and evaluation of acidizing treatments do not consider the temperature and mineralogy effects extensively. We studied one such software and developed recommendations to improve the design and evaluation of sandstone acidizing treatments by taking into account the multifaceted effects of temperature and mineralogy in increasingly deep and hot sandstone environments. These recommendations will be of great use in the times to come as most of the wells will have to be drilled at greater depths in search for new reserves.Item Detection of water or gas entry into horizontal wells by using permanent downhole monitoring systems(Texas A&M University, 2007-09-17) Yoshioka, KeitaWith the recent development of temperature measurement systems, continuous wellbore temperature profiles can be obtained with high precision. Small temperature changes can be detected by modern temperature-measuring instruments, such as fiber optic distributed temperature sensors (DTS) in intelligent completions. Analyzing such changes will potentially aid the diagnosis of downhole flow conditions. In vertical wells, temperature logs have been used successfully to diagnose the downhole flow conditions because geothermal temperature differences in depth make the wellbore temperature sensitive to the amount and the type of fluids flowing in the wellbore. Geothermal temperature does not change, however, along a horizontal wellbore, which leads to small temperature variations in horizontal wells, and interpretations of temperature profiles become harder to make than those for vertical wells. For horizontal wells, the primary temperature differences are caused by frictional effects. Therefore, in developing a thermal model for producing horizontal wellbore, subtle temperature changes should be accounted for. This study rigorously derives governing equations for thermal reservoir and wellbore flow and develops a prediction model of temperature and pressure. With the prediction model developed, inversion studies of synthetic and field examples are presented. These results are essential to identify water or gas entry, to guide the flow control devices in intelligent completions, and to decide if reservoir stimulation is needed in particular horizontal sections. This study will complete and validate these inversion studies. The utility and effect of temperature and pressure measurement in horizontal wells for flow condition interpretation have been demonstrated through synthetic and field examples.Item Early-age concrete temperature and moisture relative to curing effectiveness and projected effects on selected aspects of slab behavior(2009-05-15) Ye, DanConcrete curing has long been realized to be important to produce durable concrete. Curing compound is widely used to cure concrete in the field. The current curing membrane evaluation method ASTM C 156, however, is incapable of distinguishing the curing compound quality and guiding the curing practice in the field. A new laboratory curing membrane evaluation protocol is developed in this study. It has the ability to rank the quality of curing compound and guide curing practice in the field according to the field ambient weather conditions and the type of curing compound. A series of field tests were conducted to investigate the key factors that affect the curing effectiveness in the field conditions. A finite element program, temperature and moisture analysis for curing concrete (TMAC2), is updated to solve the coupled and nonlinear heat transfer and moisture transport problems in early-age concrete. Moisture capacity is induced into the TMAC2, which makes it unique to characterize the self-desiccation. A full scale concrete pavement test study was conducted at the FAA National Airport Pavement Test Facility (NAPTF) near Atlantic City, New Jersey. In this study, the material properties, i.e. thermal conductivity and moisture diffusivity, were backcalculated from field data. Thereafter, backcalculated material properties were used to forward-calculate the temperature and moisture histories of all other sections. High order shear deformable theory is used to model the concrete slab curling and warping behavior because of highly nonlinear temperature and moisture gradients. The maximum shear strain is obtained a couple of inches below the concrete slab. This might account for the occurrence of delamination.Item Effects of Nutrient Supply and Cooling on Growth, Flower Bud Differentiation, and Propagation of the Nobile Dendrobium Orchid(2009-05-15) Yen, Christine Yung-TingStudies of Dendrobium Sea Mary ?Snow King? investigated the effect of nutrient termination (1 Aug., 1 Sept., or 1 Oct.) and reapplication [at the beginning, in the middle, immediately after, or 2 weeks after (relative to cooling), or no nutrient reapplication] on growth and flowering, quantified cooling requirements (10, 13, 15, or 18 ?C for 2 to 6 weeks) for flowering, and determined optimum nutrient termination (on the three above dates) and nutrient rate (0.33, 0.67, or 1.33 g?L-1 15N-2.3P-12.9K) for producing single-node cuttings. Regardless of reapplication stages, nutrient termination on 1 Oct. caused taller plants with more nodes, more leaves, more flowering nodes, more total flowers, and fewer aborted flowers than those being terminated earlier. Only buds protruding above 2 mm from pseudobulb surface showed differentiated floral structures. Plants with 1 Aug. nutrient termination had larger flower primordia than those with 1 Oct., indicating flower differentiated earlier or faster with an earlier nutrient termination. No reversion of reproductive to vegetative buds arose due to either late nutrient termination or resumption of nutrients during cooling. Interactions between temperature and cooling duration were significant on time required for anthesis and full flowering, recorded from either beginning or completion of cooling, average flower number per flowering node, and flower diameter. Increasing cooling duration from 2 to 6 weeks led plants to reach anthesis and full flowering faster after cooling; however, the increasing cooling duration actually extended total time for producing flowering crops. Increasing temperature from 10 to 15 ?C accelerated flowering after cooling. Plants had more flowering nodes and total flowers when cooled at 10 to 15 ?C than at 18 ?C. The results suggest that 3 weeks of cooling at 13 or 15 ?C produce quality flowering plants that require less time to reach flowering. Plants fertilized at 0.67 or 1.33 g?L-1 were taller with 18% more nodes and more leaves than those receiving 0.33 g?L-1. Increasing nutrient rate with prolonged supply to the plants caused more single-node cuttings to grow into vegetative shoots for propagation, fewer cuttings to transition to flowering nodes, and less flower abortion to occur.Item Field application of an interpretation method of downhole temperature and pressure data for detecting water entry in horizontal/highly inclined gas wells(2009-05-15) Achinivu, Ochi I.In the oil and gas industry today, continuous wellbore data can be obtained with high precision. This accurate and reliable downhole data acquisition is made possible by advancements in permanent monitoring systems such as downhole pressure and temperature gauges and fiber optic sensors. The monitoring instruments are increasingly incorporated as part of the intelligent completion in oil wells where they provide bottomhole temperature, pressure and sometimes volumetric flow rate along the wellbore - offering the promise of revolutionary changes in the way these wells are operated. However, to fully realize the value of these intelligent completions, there is a need for a systematic data analysis process to interpret accurately and efficiently the raw data being acquired. This process will improve our understanding of the reservoir and production conditions and enable us make decisions for well control and well performance optimization. In this study, we evaluated the practical application of an interpretation model, developed in a previous research work, to field data. To achieve the objectives, we developed a simple and detailed analysis procedure and built Excel user interface for data entry, data update and data output, including diagnostic charts and graphs. By applying our interpretation procedure to the acquired field data we predicted temperature and pressure along the wellbore. Based on the predicted data, we used an inversion method to infer the flow profile - demonstrating how the monitored raw downhole temperature and pressure can be converted into useful knowledge of the phase flow profiles and fluid entry along the wellbore. Finally, we illustrated the sensitivity of reservoir parameters on accuracy of interpretation, and generated practical guidelines on how to initialize the inverse process. Field production logging data were used for validation and application purposes. From the analysis, we obtained the production profile along the wellbore; the fluid entry location i.e. the productive and non-productive locations along the wellbore; and identified the fluid type i.e. gas or water being produced along the wellbore. These results show that temperature and pressure profiles could provide sufficient information for fluid identity and inflow distribution in gas wells.Item Genetic and Biochemical Analysis of Innate Immunity in Arabidopsis thaliana(2013-11-08) Cheng, ChengPerception of evolutionarily conserved pathogen-associated molecular patterns (PAMPs) elicits rapid and profound transcriptional reprogramming in hosts and activates defense to pathogen attack. The molecular signaling networks underlying this plant pattern-triggered immunity (PTI) remain fragmented. We identified a series of mutants with altered pFRK1::LUC activity were identified and named as Arabidopsis genes governing immune gene expression (aggie) through forward genetic screening. Map-based cloning identified Aggie1 as encoding Arabidopsis C-terminal domain (CTD) phosphatase-like 3 (CPL3), a homolog of yeast FCP1 phosphatase that dephosphorylates the CTD of RNA polymerase II (RNAPII) during the transcription cycle. MAMP perception induced a rapid and transient CTD phosphorylation in Arabidopsis, underlying the modulation of CTD phosphorylation dynamics controlling plant immune responsive gene expression. Aggie1/CPL3 specifically dephosphorylated Ser2 of the CTD in vivo and in vitro and preferentially interacted with phosphorylated CTD. Transcriptional analysis indicates that cpl3 showed overall enhanced flg22-mediated transcription responses. Thus, Aggie1 negatively regulates immune responsive gene expression essential for suppression of pathogen growth by modulating the phosphorylation status of RNAPII CTD. Cyclin-dependent kinases C (CDKC) functions as RNAPII kinases. Interestingly, we also found the silencing of cdkc1 and cdkc2 in wild type reduced flg22-mediated transcription responses and the plants were more susceptible to Pseudomonas syringae DC3000, suggesting their positive role in PAMP-triggered immunity. Temperature fluctuation is a key determinant for microbial invasion into the host and for host evasion of the microbe. In contrast to mammals that maintain constant body temperature, plant internal temperature oscillates on a daily basis. It remains elusive how plants operate inducible defenses in response to temperature fluctuation. We report that ambient temperature changes lead to pronounced shifts of two distinct plant immune responses: pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI). Plants preferentially activate ETI signaling at relatively lower temperatures (10~23?C), whereas they switch to PTI signaling at moderately elevated temperatures (23~32?C). The Arabidopsis arp6 and hta9hta11 mutants, phenocopying plants grown at the elevated temperatures, exhibit enhanced PTI and yet reduced ETI responses. As the secretion of bacterial effectors favors low temperatures whereas bacteria multiply vigorously at elevated temperatures accompanied with increased MAMP production, our findings suggest that temperature oscillation might have driven dynamic co-evolution of distinct plant immune signaling responding to pathogen physiological changes.Item Laser Scattering as a Tool to Determine the Effect of Temperature on Diatom Aggregation(2011-10-21) Rzadkowolski, Charles EdwardDiatoms are estimated to contribute 25 percent of the primary production on Earth and therefore they play a significant role in the global carbon cycle. Diatom blooms often terminate with the formation of aggregates that sink rapidly from surface waters, affecting the flux of organic carbon from the surface to deep waters and the sea floor. The role of carbon-rich transparent exopolymeric particles (TEP) in aggregate formation as ocean temperature increases has yet to investigated in continuous cultures. I hypothesize that temperature increase can influence the production of TEP, a fraction of total suspended exopolymers. To test the hypothesis, a laser in situ scattering and transmissometry instrument (LISST-100X, Sequoia Instruments) successfully counted and sized six individual diatom species in batch culture: Chaetoceros muelleri, Coscinodiscus wailesii, Thalassiosira weissflogii, Phaeodactylum tricornutum, Skeletonema costatum, and Skeletonema marinoi and successfully demonstrated its efficacy in detecting diatom aggregates using S. costatum. Four replicate continuous cultures were sampled for particle size distribution (PSD), nutrients, chlorophyll a, total carbohydrates, prokaryote concentration, and TEP at temperatures of 22.5, 27 and then 20 degrees C. While TEP particles were scarce, acid polysaccharide (APS)-coated C. muelleri cells were observed, forming dense webs on the filters. Both carbohydrate per cell and APS area per cell were found to significantly correlate with temperature (p<0.05) while significant difference between APS concentration at each temperature was only found between 27 and 22.5 or 20 degrees C (p<0.05). Net changes in PSDs with increasing temperature showed that distributions of relative volume concentration decreased in the smallest size bins and increased in the largest size bins. Our results show that increasing the temperatures of nitrogen-limited C. muelleri cultures did not cause increased TEP formation but instead resulted in increased cell-surface coating. Increasing concentration of cell coatings and TEP particles will cause diatoms to aggregate more readily, enhancing their sinking rate away from the ocean surface. Increased ocean temperature has great implications for diatom blooms and other microorganisms, causing greater export of carbon out of the surface waters and potentially altering the microbial loop.Item Temperature and Scaling Studies from Projectile Fragmentation of 86,78Kr+64,58Ni at 35 MeV/A.(2010-01-14) Wuenschel, Sara K.Many observables have been developed to study the effects of the two component nature of nuclei. This dissertation has experimentally probed caloric curves as well as scaling observables for their dependence on the asymmetric portion of the nuclear equation of state. Projectile fragmentation sources were identified from the reactions of 86,78Kr+64,58Ni at 35 MeV/A taken on the NIMROD-ISiS array. The angular coverage, excellent isotopic resolution, and Neutron Ball allow for quasi-complete event reconstruction in both charge and mass. A new thermometer for nuclear fragmentation studies has been derived and is presented here. In this thermometer, the temperature is obtained from fluctuations of the transverse momentum. The proton transverse momentum fluctuations are used in this thesis to study the N/Z dependence of the nuclear caloric curve. The caloric curve constructed from proton momentum fluctuations does not show a significant dependence on the source N/Z ratio. Two other thermometers have also been studied in this thesis: the double isotope ratio, and moving source slope thermometers. These thermometers show no statistically significant dependence on the source N/Z. The source density has been derived from the evolution of fragment Coulomb barriers with increasing E*/A. This density showed no source N/Z dependence. However, a strong evolution in source density over the E*/A=1.5-7.5 MeV region was observed. Fragment scaling was investigated through isoscaling and power law scaling. The power law scaling showed a strong dependence on the source N/Z. This source N/Z dependence was further investigated through isoscaling. The fragment yields of this data have been shown to exhibit consistent isoscaling for Z=1-17. In addition, isoscaling was observed in data cut on the E*/A of the source yielding decreasing slopes (a) as a function of E*/A. This decrease, normalized to the asymmetries of the sources (a/delta), has been linked to a decrease in the asymmetry coefficient Csym. This dissertation has shown that the experimentally observed decrease in Csym with E*/A is well correlated to the temperature and density changes experimentally observed in this data.Item The effects of temperature and humidity on the eggs of Aedes aegypti (L.) and Aedes albopictus (Skuse) in Texas(2009-05-15) Dickerson, Catherine ZindlerCausative influences that impact the separation of Ae. aegypti and Ae. albopictus populations in different geographic areas were determined, as well as how they are affected by the abiotic conditions as seen in the habitats they frequent in Texas. The eggs of Ae. albopictus and Ae. aegypti collected from McAllen and Brownsville, Texas, and laboratory populations of these two species were subjected to 25 different temperature and relative humidity conditions for up to three months. In most treatments, Ae. aegypti eggs had a greater percent hatch than Ae. albopictus, regardless of temperature or relative humidity. With an increase in relative humidity, the percent hatch for both species increased, but at the higher temperatures of 32? and 35?C the amount of time the eggs were exposed to those temperatures had a greater negative effect on the percent hatch than did the positive effect of increase in relative humidity. The surface area, volume and surface-area-to-volume ratio of Ae. aegypti and Ae. albopictus eggs with and without the chorionic egg pad, and the size of the chorionic egg pad were calculated for fifty eggs of each species of mosquito from populations collected in McAllen and Brownsville and from the laboratory populations. Ae. aegypti had a larger egg volume, and a larger surface area; but, it is likely their larger egg pad compensates for this high surface-area-to-volume ratio by holding moisture along the egg?s surface and that the egg pad is associated with the high desiccation resistance seen in Ae. aegypti eggs. Development rates for both species of mosquitoes from populations collected in Galveston and Brownsville, Texas, and laboratory populations were produced by measuring the development time from a hatched egg to the adult at seven temperatures. The temperature optima (28?-33?C) were similar for all populations; however, the rate of development for Ae. aegypti was significantly faster at the temperature optima. It is likely that this faster development rate in the Ae. aegypti population helps to maintain a population in climates that have this range of temperatures given that Ae. albopictus is a superior competitor in the larval and adult stages.Item The Molecular and Physiological Basis for Temperature Mediated Regulation of Dwarfness in Tifdward Bermudagrass(2014-04-03) Abernathy, ScottTifdwarf (C. dactylon (L.) Pers. x C. transvaalensis (Burtt-Davies) has been used on putting greens in the southern US for over 50 years. Dwarfism in Tifdwarf (TD) bermudagrass is a conditional trait. Tifdwarf internodes and leaves elongate when exposed to suboptimal temperatures. This study further quantified physiological aspects of this response and investigated the role of gibberellins in the temperature mediated release of TD dwarfism. In controlled environment studies, TD internode and leaf lengths were two times longer in suboptimal (27?C/19?C day/night) compared to optimal temperatures (35/27?C). In NuMex Sahara (NM), a non-dwarf bermudagrass, internode and leaf length decreased or showed no response to suboptimal temperatures. When grown under suboptimal temperatures, TD accumulated the same or less biomass than optimal treatments. NM accumulated less biomass. Suboptimal temperature reduced respiration in TD but had no affect on photosynthesis. To investigate the role of gibberellins in conditional dwarfism, expression patterns for GA20ox1, GA20ox2, GA3ox, GA2oxa, GA2oxb and GAMyb were analyzed. Under optimal temperatures, GA20ox2 and GA3ox expression were higher and GA2oxa expression was lower in TD than NM. Similar expression patterns are common in many GA associated dwarf mutants. Despite limited phenotypic differences in NM given different temperature treatments, GA20ox2 and GA3ox were elevated and GA2oxa and GAMyb were depressed in suboptimal treatments. Unlike NM, and despite robust phenotypic changes, TD displayed minimal molecular responses to suboptimal temperatures. Only GA2oxa and GA2oxb displayed differential expression patterns between treatments. Both were higher in the suboptimal temperature regime. The GA biosynthetic inhibitors CCC and flurprimidol decreased TD internode length while GA3 increased length under both temperature treatments, however internodes from suboptimal treatments remained longer than optimal treatments. Trinexapac-ethyl also decreased internode length in both temperature treatments, but at the high application rate, no difference was measured between temperature treatments. Therefore, functional late-stage GA metabolic and/or catabolic enzymes are required for temperature mediated adjustments in TD morphology. No difference due to temperature was observed in bermudagrass internode length when an inhibitor combination plus GA3 was applied. This suggests that the temperature mediated adjustments in morphology are not the result of altered GA sensitivity.Item Transient Temperature Modeling For Wellbore Fluid Under Static and Dynamic Conditions(2014-04-22) Ali, MuhammadModeling flowing wellbore fluid transient temperature is important in many petroleum engineering problems, including, pressure transient testing, flow assurance and wellbore integrity during production, preservation of drilling equipment integrity for geothermal wells and prediction of injection fluid temperatures. In this thesis, development and usage of three models for transient fluid temperature are presented. Two models predict transient temperature of flowing fluid under separate flow configurations and one is for a static fluid column. Additionally, an improvement to an existing transient temperature solution is given. The transient rate model predicts the transient temperature when a flow rate, during production, is changed from some initial value to a new one. This model is particularly useful for pressure transient tests involving multiple disparate constant flow rates where bottomhole pressure has to be calculated from the wellhead pressure. Dependence of fluid density on variable temperature during the test necessitates that effects of unsteady temperature changes are taken into account for accurate calculation of downhole pressure. The single rate injection model predicts transient temperature of wellbore fluids during injection operations. This model can help in design of acidizing treatments by allowing users to calculate the time required to cool down the well with water pre-flush. This model can also be used for calculation of depth of effectiveness of wax removal treatment, in case of hot oil injection. Very high temperatures during drilling operations can deteriorate mud rheological properties. The conduction model lets the user calculate the time window available for taking corrective actions after an accidental cessation of mud circulation occurs. Method of Laplace transform enabled solution of a temperature distribution equation to create the transient rate model and the injection model. Conduction model was developed by solving the transient heat conduction equation for a multilayer cylinder with mud in annulus and tubing analogous to two layers of the cylinder. All solutions were implemented using conventional spreadsheet software with rudimentary programming.Item Utilizing body temperature to evaluate ovulation in mature mares(Texas A&M University, 2006-08-16) Bowman, Marissa CoralThe equine breeding industry continues to be somewhat inefficient, even with existing technology. On average, foaling rates are low when compared with that of other livestock. One major contributor is the inability to accurately predict ovulation in mares, which ovulate before the end of estrus, leaving much variability in coordinating insemination. A more efficient, less invasive method that could replace or reduce the need for constant teasing and ultrasonography to evaluate follicular activity is needed. In both dairy cattle and women, a change in body temperature has been shown to occur immediately prior to ovulation. Research on horses has been limited, although one study reported no useable relationship between body temperature and ovulation in mares (Ammons, 1989). The current study utilized thirty-eight mature cycling American Quarter Horse mares, and was conducted from March-August 2004. Each mare was implanted in the nuchal ligament with a microchip that can be used for identification purposes, but is also capable of reporting body temperature. Once an ovulatory follicle (>35mm) was detected using ultrasonography and the mare was exhibiting signs of estrus, the mare's follicle size and temperature were recorded approximately every six hours until ovulation. Not only was the temperature collected using the microchips, but the corresponding rectal temperature was also recorded using a digital thermometer. A significant effect (p<0.05) on body temperature was noted in relation to the presence or absence of an ovulatory follicle (>35mm) under different circumstances. When evaluating the rectal temperatures, no significant difference was found in temperature in relation to the presence or absence of a follicle. However, in the temperatures obtained using the microchip, temperature was higher (p<0.05) with the presence of a follicle of greater than 35mm. This may be due to the extreme sensitivity of the microchip implant and its ability to more closely reflect minute changes in body temperature.