Browsing by Subject "Temperature"
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Item AMPHIBIANS OF THE SOUTHERN GREAT PLAINS: HABITAT AND THE IMPACTS OF TEMPERATURE AND pH ON SURVIVAL(2013-05) Kissner, Jessica; Griffis-Kyle, Kerry; McIntyre, Nancy E.; Haukos, David A.; Wallace, Mark C.Global climate change has had an increasing role in the decline of amphibian populations due to direct (e.g. critical temperature thresholds) and indirect (e.g. temperature stress, spreading of disease, and habitat alteration and loss) effects of increasing atmospheric temperature. Due to the complexity of habitats needed to complete all of their life stages, amphibians are subject to stressors through a number of systems (e.g., water quality, climatic characteristics, and terrestrial habitat). Furthermore, habitat currently used by amphibians may become inhospitable due to indirect stressing effects of increased temperatures projected for the Southern Great Plains (SGP). To protect and manage for species at risk, we must first understand their basic community assemblages, distributions, habitat associations, and tolerances. Because little amphibian research has come from northeastern New Mexico, collecting data on these parameters will be a useful tool for future research and management in this area. The objectives of this study were to: (1) examine amphibian species presence, richness, an index of reproductive success, and larval growth in northeastern New Mexico and relate them to site-specific and landscape-level habitat characteristics and (2) identify environmental factors that may jeopardize population persistence in the future. After conducting field work, I determined an additional objective based on the current average high temperature (28.3°C) and pH ranges (4.9 to 9.4) I recorded: (3) to determine the effect of a 5.6°C increase in average summer temperature by 2090 (to 33.9°C) due to climate change on embryo and tadpole survival, the effects of pH 4.9 and 9.4 on embryo and tadpole survival, and the effects of the interactions between pH and temperature on embryo and tadpole survival. Over 2011 and 2012, I sampled each playa wetland 5 times over a 17-day sampling period after precipitation of >2cm using call, visual encounter, egg mass, dip net, and funnel trap surveys to examine the amphibian community. I also collected tadpole measurements throughout development to examine larval growth patterns. Water quality was sampled during each survey, and ArcMap was employed to determine landscape-level habitat features. I sampled 14 playa wetlands in northeastern New Mexico, detecting 7 amphibian species with a maximum species richness per playa of 4. I detected reproduction in 4-6 species (as Pelobatid tadpoles are difficult to identify to species), and larval growth in Anaxyrus cognatus, Pseudacris clarkii, and Pelobatid spp. was exponential up to age 17 days (all p < 0.01). I also documented the first New Mexico state record of Pseudacris clarkii (spotted chorus frog). Although I did not document any statistically significant associations between amphibian species presence, richness, or reproductive success and habitat characteristics, I observed a trend of no P. clarkii reproduction at the acidic sites (4.9-6.9) even though adults were present in playa wetlands with pH 4.9-9.4. Based on my field observations about amphibian natural history from 2011, I hypothesized that increased temperature due to global climate change in 2090 may influence the ability of anurans to survive in pH-stressed playas. I tested these hypotheses in the lab in order to strengthen my field-based inferences. In 2012, I performed a fully-factorial laboratory experiment using the 2011 pH extremes (4.9 and 9.4), 2011 current average temperature (28.3°C), and 2090 projected temperature (33.9°C ), with embryos from 3 pairs of wild-caught P. clarkii. The results of my experiment suggest that P. clarkii cannot successfully reproduce in water with high temperature (33.9°C), regardless of the pH conditions. Furthermore, survival to metamorphosis in acidic conditions (pH 4.9), regardless of temperature, is unlikely, findings consistent with both my field observations and laboratory results. Survival to metamorphosis in basic conditions (pH 9.4) is very low (9%), compared to survival at pH 7 (84 %) that other studies have documented. Based on my findings, an increase in summer temperature of 5.6°C over the next 70 years will likely cause mortality and extirpation of some amphibian species in the Southern Great Plains. My results demonstrate the threat to P. clarkii due to projected climate change and suggest that other amphibian species may also be vulnerable, particularly for anuran populations that are at the edge of their range such as Gastrophryne olivaea, a New Mexico state-endangered species. By combining field and laboratory techniques and coming to a similar conclusion, I have been able to provide conclusions about the effect of temperature and pH on amphibian survival and population persistence.Item Continuous canopy temperature as a tool for managing deficit irrigation(2012-12) Young, Andrew W.; Dotray, Peter A.; Mahan, James R.; Payton, Paxton R.Deficit irrigation is becoming a trend in agricultural lands with reduced water. With the declining water resources comes renewed interest in deficit irrigation strategies and enhanced management capabilities to provide water when and where it is needed. However, in the past, plant-monitoring capabilities to assess water status of the plant were very costly and labor intensive. The innovation in infrared thermometry systems has allowed for the technology to become smaller and more cost efficient. This investigation uses the established method of BIOTIC developed by research scientist at USDA/ARS. The BIOTIC method has been patented and licensed by a new technology startup company, Smartfield™, under the moniker Smartcrop™. The research conducted used the Smartcrop™ technology, which consists of wireless infrared sensors and base stations for recording data from sensors. This thesis focused on the 2009 and 2010 cotton growing seasons in the Lubbock area. Water and yield data were discussed and analyzed in detail along with other environmental data relevant to plant growth and yield. Analysis and discussion of large temperature data sets were conducted. Canopy temperature comparisons were made using the BIOTIC method along with air vs. canopy temperature comparisons and treatment temperature comparisons. Vapor pressure deficits were also discussed in detail for selected treatments over the growing seasons. Finally, daytime average canopy temperature comparisons provided accurate estimates of water through the plant as a predictor of yield.Item Density and Temperature in Quantum Nuclear Systems(2014-10-01) Zheng, HuaOne of the goals of nuclear physics is to study the Equation of State (EOS) of nuclear matter. In order to create the nuclear matter at different densities, we collide different nuclei and detect the fragments after the collisions with different beam energies in the laboratory. Then we extract information about finite nuclei by analyzing the collected data with different assumptions. As we know, quantum effects play an important role in many systems: the Cosmic Microwave Background (CMB) radiation, the specific heat of different metals, the suppression of density uctuations in a trapped Fermi gas, the enhancement of density fluctuations in a trapped Bose gas, the observation of Fermi pressure in trapped mixed Fermi and Bose gases, etc. The nucleus is a quantum many body system made of strongly interacting fermions, protons and neutrons (nucleons). Therefore, we are dealing with fermions and bosons in the nucleus-nucleus collisions. It is clear that we need to take into account the genuine quantum nature of particles when we extract the physical quantities for the EOS. In the past, some methods have employed the classical limit of low density and high temperature, e.g. double ratio thermometer, while other methods (e.g. two particle correlation) implement some quantum effects but they are only able to calculate one physical quantity, i.e. density p or temperature T. We would like to develop a method which takes into account the quantum nature of particles to extract the temperature and density of nuclear matter created in heavy-ion collisions. In this dissertation, we propose a new thermometer which includes quantum effects as manifested in quadrupole momentum fluctuations and multiplicity fluctuations of the detected particles. In the same framework, we are able to calculate the density of the studied particles. To test our method, we use the Constrained Molecular Dynamics (CoMD) model, which incorporates the Pauli principle, and we simulate the 40Ca + 40Ca collisions at different beam energies at impact parameter b = 1 fm up to 1000 fm/c. Later, we apply our method to do data analysis and extract the temperatures and densities for fermions and bosons respectively. The Fermi quenching for fermions is found in the simulation data. It has been confirmed in different experimental data. We also studied the possible Bose-Einstein condensate (BEC) for bosons in the same framework with CoMD and CoMD? which includes the boson correlations. Comparing the results with neutron case, we can see that the Coulomb effects play a role in the data analysis. To explore our method even further, we introduce the Coulomb correction for charged particles (both fermions and bosons). A method borrowed from electron scattering was adopted and applied to classical as well as quantum systems. In the model calculations, it was observed that when taking into account those effects, the T of p and n (as well as composite fermions in the classical case) are very similar, while the densities are not affected by the corrections. But for bosons, the temperatures and densities are very similar to the neutron case.Item Effect of temperature, dissolved inorganic carbon and light intensity on the growth rates of two microalgae species in monocultures and co-cultures(2014-05) Almada-Calvo, Fernando; Kinney, Kerry A.; Katz, Lynn E.The enormous biodiversity of microalgae as well as their high photosynthetic rates can be exploited for a wide variety of applications including the production of high value chemicals, nutraceuticals, aquaculture feed, and most recently, biofuels. Regardless of the application, the productivity of the microalgae culture must be optimized in order to make the systems economically feasible. One environmental factor that greatly affects the productivity of mass cultivation systems is temperature since it can be prohibitively expensive to control in outdoor systems. Temperature affects microalgae growth rates both directly by its effect on metabolic rates, and indirectly, by changing the bioavailability of the inorganic carbon present in solution. In the first part of this research, the effects of dissolved inorganic carbon (DIC) concentration (varied by sparging CO₂-enriched air) and temperature on the growth of a model microalga species (Nannochloris sp., UTEX LB1999) were investigated in a turbidostat bioreactor. The results indicate that increasing DIC concentration yields higher microalgae growth rates up to an optimum value (around 3 mM for Nannochloris sp.) but higher concentrations actually inhibited growth. Since increasing the temperature decreases the DIC concentration for a given gas pCO₂, it is necessary to adjust the pCO₂ to maintain the target DIC concentration in the optimal range for growth. In the next phase of the research, the effect of average light intensity (Gav) and temperature on the growth rate of two microalgae species (Nannochloris sp., UTEX1999. and Phaeodactylum tricornutum, UTEX646) was investigated. Growth rates were measured over a range of average light intensities and temperatures using a turbidostat bioreactor. A multiplicative model was developed to describe growth as a function of both average light intensity and temperature. In the third phase of this research, both microalgae species were grown together to explore the effects of temperature fluctuations on the population dynamics of the co-culture. It was observed that Nannochloris was inhibited by the presence of P. tricornutum in the medium, probably due to the excretion of secondary metabolites into the medium that affected Nannochloris growth (allelopathic effects). The temperature and average light intensity model developed under monoculture conditions was modified to incorporate the allelopathic effects observed. The resulting model provided a reasonable fit to the dynamic behavior of a Nannochloris/P. tricornutum co-culture subjected to temperature variations in chemostat experiments.Item Effects of auditory and thermal stimuli on 3,4- methylenedioxymethamphetamine (MDMA)-induced neurochemical and behavioral responses(2009-12) Feduccia, Allison Anne; Duvauchelle, Christine L.The amphetamine derivative, 3,4-methylenedioxymethamphetamine (MDMA), is a popular drug often taken by young adults at dance clubs or rave parties. Laser light shows, fast-paced electronic music, and hot crowded dance floors are characteristic of these events, and Ecstasy users report that the acute effects of the drug are potentiated by these stimulatory conditions. However, it remains largely unknown how environmental stimuli impact the neurochemical and physiological effects of MDMA. The aim of the first study presented in this dissertation was to investigate how auditory stimuli (music, white noise, and no additional sound) influence MDMA conditioned place preference (CPP), self-administration, and nucleus accumbens (NAcc) dopamine (DA) and serotonin (5-HT) responses. Findings revealed a significant CPP for animals exposed to white noise during MDMA conditioning trials. After self-administration of MDMA (1.5 mg/kg), NAcc DA and 5-HT were highest in rats exposed to music during the test session. The second study aimed to investigate the effects of ambient temperature (23°or 32°C) on long-term MDMA self-administration and neurochemical responses. Results indicated no difference in self-administration or locomotor activity rates for the high versus room temperature groups across sessions. However, MDMA (3.0 mg/kg) administered in high ambient temperature resulted in significantly greater NAcc serotonin release compared to when taken at room temperature, but no differences in dopamine response was determined between the two conditions. Overall, these results indicate that auditory and thermal stimuli can effect MDMA-induced behavioral and neurochemical responses. The last aim tested a novel apparatus and method for use in animal models of drug reinforcement. By combining traditional CPP and self-administration procedures, this approach provided more informative data and circumvented some inherent drawbacks of each method alone. In addition to confirming the ability to produce drug conditioned place preferences after short- and long-term experiments, the long-term version of the procedure revealed a significant positive relationship between lever response rate and CPP magnitude. Therefore, this experimental design can be used to identify subgroups of rats that may vary in sensitivity to drug motivational effects. Further study of these populations may be useful in the development of behavioral and pharmacological therapies for drug addiction.Item Estimating climatic influence on spatial and temporal variations of grassland gross primary production: A remote sensing approach(2007-05) El-Masri, Bassil; Rahman, A. Faiz; Tissue, David T.; Fish, Ernest B.The influence of climate change on the global carbon (C) cycle, as well as changes in ecosystem properties that affect climate, are two active areas of research in global change studies. Examining spatial and temporal climate variations and their relationships with grassland gross primary production (GPP) is important to quantify this biome’s role in the global carbon cycle and climate dynamics. Remote sensing is an important method to study these spatially explicit phenomena. The primary objective of this study is to couple variations in US grassland GPP to spatial and temporal variations in precipitation and temperature. The spatial and temporal variability in grassland gross primary production (GPP) was assessed for four years (2001 – 2004). At continental scale, GPP was positively correlated with annual (January to December), hydrological year (September to August) precipitation, and temperature. Multiple linear regressions between precipitation, temperature, and their interaction improved the correlation with GPP. Highest values of correlation were observed on the south and north of the study area. However, hydrological year precipitation showed better correlation with grassland GPP suggesting that a time lag of 3 months exist between hydrological year precipitation and annual precipitation when correlated with vegetation growth. Modeling using ECOSYS and climatic model precipitation data suggested that under high CO2 emission scenario, grassland GPP will increase especially in the northern parts of the study area.Item Evaluation of test methods to measure cold tolerance in cotton(Texas Tech University, 1999-12) Schulze, Daniel H.Profitable cotton (Gossypium hirsutum L.) production on the Southern High Plains of Texas is dependent upon an interaction of many environmental and physiological factors that vary from year to year. The first goal in cotton production is the establishment of a uniform and vigorous healthy stand of seedlings in the field. The establishment of an ideal stand of cotton seedlings on the Southern High Plains, where planting typically begins in May, is often impaired by suboptimum environmental conditions. Environmental conditions during planting are characterized by cool nights due to the areas high elevation, low relative humidity, and lingering cold fronts. These environmental conditions allow for temperatures to fall below critical levels for optimum seedling germination and establishment such that seedlings may experience chilling injury. Producers, however, often must plant in these suboptimal and potentially detrimental conditions because of the area's short growing season. This allows the crop to mature before temperatures drop below critical levels for crop maturation in the fall which would compromise lint yield and quality. Low temperatures play a critical role in seedling germination, establishment, growth and development of many tropical and subtropical crops such as cotton which are chilling sensitive. Crops that are chillng sensitive are injured or killed by low temperatures that are well above freezing. Chilling injury in cotton is characterized by low germination, low vigor seedlings, aborted radicle root tips, and delayed crop maturation. The optimum temperature for cotton seedling germination and establishment is between 30-35° C. Physiological zero for cotton is considered around 15° C, although chilling damage has been reported as high as 20° C.Item Gas Seal Leakage at High Temperature: A Labyrinth Seal and an All-Metal Complaint Seal of Similar Clearance(2013-07-31) Anderson, AlainReducing secondary leakage is a common challenge in numerous machines, particularly in steam and gas turbines. Too large leakage in seals produces a substantial loss in efficiency and power delivery with an increase in specific fuel consumption. Various seal types exist, each with unique advantages and disadvantages as per leakage, power loss, and wear. Labyrinth seals are most common due to their simple design and low cost. Their main drawback is a too high leakage due to enlarged (worn) clearances when a rotor vibrates. More complicated seal types, such as brush seals can withstand rotor excursions and ensure lower leakage rates than with labyrinth seals. Brush seals utilize a bristle bed which contacts the rotor and wears out thereby reducing leakage performance. The HALOTM seal, an all-metal seal with flexibly supported shoes, is engineered as a clearance control seal to reduce leakage even more, in particular for operation with high pressure differentials and with high surface rotor speeds. Static leakage tests with hot air at a high temperature (max. 300?C) conducted in a test rig holding a labyrinth seal and a novel all-metal seal (HALOTM seal), both of the same diameter, length and clearance, show the novel seal leaks ~1/5 the flow of a labyrinth seal for pressure ratios (Ps/Pa) > 3.5. The savings in leakage are maximized during operation at high pressure differentials. Leakage measurements with a rotor spinning to a maximum speed of 2,700 rpm (surface speed = 23.6 m/s) produce a slight decrease in leakage with increasing rotor speed. The research product is a reliable leakage data base enabling the application of a state of the art sealing technology that increases system efficiency by reducing leakage and extends maintenance intervals by eliminating wear of components.Item High Temperature, Permanent Magnet Biased Magnetic Bearings(2010-07-14) Gandhi, Varun R.The Electron Energy Corporation (EEC) along with the National Aeronautics and Space Administration (NASA) is researching magnetic bearings. The purpose of this research was to design and develop a high-temperature (1000?F) magnetic bearing system using High Temperature Permanent Magnets (HTPM), developed by the EEC. The entire system consisted of two radial bearings, one thrust bearing, one motor and 2 sets of catcher bearings. This high temperature magnetic bearing system will be used in high performance, high speed and high temperature applications like space vehicles, jet engines and deep sea equipment. The bearing system had a target design to carry a load equal to 500 lb-f (2225N). Another objective was to design and build a test rig fixture to measure the load capacity of the designed high temperature radial magnetic bearing (HTRMB) called Radial Bearing Force Test Rig (RBFTR). A novel feature of this high temperature magnetic bearing is its homopolar construction which incorporates state of the art high temperature, 1000 ?F, permanent magnets. A second feature is its fault tolerance capability which provides the desired control forces even if half the coils have failed. The permanent magnet bias of the radial magnetic bearing reduces the amount of current required for magnetic bearing operation. This reduces the power loss due to the coil current resistance and also increases the system efficiency because magnetic field of the HTPM is used to take up the major portion of the static load on the bearing. The bias flux of the homopolar radial bearing is produced by the EEC HTPM to reduce the related ohmic losses of an electromagnetic circuit significantly. An experimental procedure was developed using the Radial Bearing Force Test Rig (RBTFR) to measure actual load capacity of the designed bearing at the test rig. All the results obtained from the experiment were compiled and analyzed to determine the relation between bearing force, applied current and temperature.Item History and Analysis of Distributed Acoustic Sensing (DAS) for Oilfield Applications(2013-05-15) Kimbell, JeremiahThe inherent nature of distributed acoustic sensing technology is a direct result of two key components: optical fiber and the speed of light. Because the speed of light is constant and optical fiber is an isolated medium, combining the two creates a mechanism insulated from environmental interference that effectively ?moves? at the speed of light. This process is most visible in the telecommunications industry where the technology transports large amounts of data over significant distances at very high speeds. The same factors that make optical fiber excellent for transporting data (high speed and low environmental interference) also make the technology very applicable for precise measuring applications. Because optical fiber is insulated, a change to the fiber will have a pronounced (measurable) effect. These measurable effects manifest themselves as changes in the amount of light that is reflected within the optical fiber. This change in reflected light can be measured and quantified to indicate both the specific location along the fiber where the change in reflection occurred and the magnitude of the change in reflection. Knowing both the location of the affected area and the extent to which the reflection changed allows for precise measuring and subsequently, educated inferences about what caused the changes initially. The ability of optical fiber to detect changes at myriad intervals over long distances has particular appeal for functions involving remote and hard to get to environments. Both of these conditions are inherent to the petroleum industry and provide substantial incentive for investigating DAS for oilfield applications.Item Increased temperature effects on fish-mediated nutrient cycling in an East Texas stream(2017-11-07) McWilliams, Jessica Lynn; Hargrave, Chad W.The unprecedented rate of global warming is an inevitable outcome of anthropogenic CO2 release into the atmosphere and complex climatic feedbacks. In ectotherms, increasing temperature may increase metabolic rates, which could enhance the energy demands of individuals and should accelerate resource acquisition. Population size and fish biomass were measured seasonally in a small second order stream over a 10-year period to examine seasonal variation in these parameters. I examined effects of increased temperature on nitrogen and phosphorus excretion in the four most abundant fish in this stream system. These fishes represent three functional feeding guilds common to many temperate stream ecosystems and comprise approximately 80-90% of the fish community. I developed temperature dependent nitrogen and phosphorus excretion models for fishes and applied these models to daily average temperatures in the stream. I then simulated climate warming (+2, +4, & +6°C) to examine the potential effects of increased temperature on fish-mediated nutrient dynamics in a southern temperate stream ecosystem. I found that increased temperature does increase nutrient cycling and nutrient flux within aquatic ecosystems; however, these effects appear to be tied to population size, biomass in addition to seasonal temperature. With increased temperature effects in spring and autumn having the greatest effect, when temperatures are cool and fish abundance and biomass is also greatest.Item Individual-based null models and resampling methods for the analysis of heterochronic differences in development(Texas Tech University, 1999-12) Konu, OzlenApplication of parametric bootstrapping and randomization methods to the analysis of heterochrony (differential timing of developmental events at the cellular or organismal level) may allow scientists to quantitatively test hypotheses about the effects of environmental variability on heterochrony. Herein, I focused on quantitative analysis and modeling of heterochrony, for (1) hierarchical (cell lineages), and (2) serial cossification sequences) developmental systems. For (1), I used the published data on embryogenesis of Caenorhabditis elegans (Schnabel et al., 1997) to simulate and compare cell lineages ('ABarpp' sublineage) at different temperatures (20 vs. 25C). The simulations suggested that the relative frequencies of the shared sequences were significantly different between groups (X^=3569, p<10'^ 10,000 iterations/group), indicating an increase in heterochrony as a response to increased temperature. The presence or absence of bilateral asymmetry in the timing of cell divisions was tested based on a null model of random sequence. Results of Wilcoxon tests on paired differences between the left and right ranks indicated that a) terminal cells on the right side of the embryo were likely to divide earlier than those on the left; and b) higher temperatures increased the degree of asymmetry. The effects of physical constraints (e.g., handedness of the early embryonic body plan) that may lead to the emergence of such an asymmetric pattern were discussed. For (2), I analyzed the ossification patterns of the vertebrae and branchial arches in the zebrafish. Danio rerio, exposed to different levels of thyroid hormone (T3). i.e., 1 ng/ml and 5 ng/ml. Onset of ossification showed a dose-dependent response to T3, such that onh at a higher dose, significant differences were observed (paired Wilcoxon tests; control vs. 1 ng/ml T3. p = 0.083; control \ s. 5 ng/ml, p = 0.002; 1 ng/ml T3 vs. 5 ng/ml T3, p = 0.004). On the other hand, the rate of vertebral ossifications was positively correlated with age for individuals exposed to 1 ng/ml T3 whereas at 5 ng/ml T3, number of ossifications reached an asymptote over time. Randomized Mantel's tests suggested that branchial arches responded to 5ng/ml T3 more than they did to 1 ng/ml T3, whereas vertebral development was accelerated at both dosages. Randomized sign tests revealed that there is a tendenc>' for the vertebrae to ossify from an anterior to posterior direction (control: p = 0.02; 1 ng/ml: p = 0.007; 5 ng/ml: p = 0.008). However, vertebrae that belong to the Weberian apparatus ossified independently of the more caudal vertebrae. This allometry suggests that the genetic and epigenetic mechanisms governing the development of cranial, Weberian, and trunk regions are at least partially decoupled. The importance of such modularity in generating novel morphs is discussed in the light of the genetic {Hox genes) and epigenetic (endocrine) mechanisms.Item The influence of temperature on the fate and transport of phthlates in indoor environments(2014-05) Bi, Chenyang; Xu, Ying (Assistant professor)Phthalate esters are extensively used as plasticizers in building materials and consumer products, but are associated with serious health concerns. They are ubiquitous indoors, redistributing from their original source to all interior surfaces, including airborne particles, dust, and skin. The main objective of the research is to investigate the influence of temperature on the fate and transport of phthalates in indoor environments. In this study, the concentrations of benzyl butyl phthalate (BBzP) and di-2-ethylhexyl phthalate (DEHP) in indoor air, settled dust, and on different interior surfaces including mirror, glass, plate, cloth and wood were measured periodically in a test house. The measurements were conducted at temperatures of 21°C and 30°C, respectively. In addition, sorption kinetics was also monitored at the temperature of 21°C. The air concentrations of BBzP and DEHP at 21°C range from 141 ng/m₃ to 210 ng/m₃ and 66 ng/ m₃ to 100 ng/ m₃, respectively. For impervious surfaces such as dish plates, the surface concentrations reached steady-state concentrations in less than 24 hours, to the level between 2 and 8 [mu]g/m₂ for both BBzP and DEHP. In contrast, the time to reach steady state was much longer for porous surfaces such as hardwood (>1 week) and dust (> months). With the temperature increase to 30°C, the gas phase concentrations of BBzP and DEHP increased by about five times, and the surface concentrations on various surfaces also increased correspondingly. This investigation suggests that temperature has an important influence on the fate and transport of phthalates in indoor environments.Item Interpreting Horizontal Well Flow Profiles and Optimizing Well Performance by Downhole Temperature and Pressure Data(2011-02-22) Li, ZhuoyiHorizontal well temperature and pressure distributions can be measured by production logging or downhole permanent sensors, such as fiber optic distributed temperature sensors (DTS). Correct interpretation of temperature and pressure data can be used to obtain downhole flow conditions, which is key information to control and optimize horizontal well production. However, the fluid flow in the reservoir is often multiphase and complex, which makes temperature and pressure interpretation very difficult. In addition, the continuous measurement provides transient temperature behavior which increases the complexity of the problem. To interpret these measured data correctly, a comprehensive model is required. In this study, an interpretation model is developed to predict flow profile of a horizontal well from downhole temperature and pressure measurement. The model consists of a wellbore model and a reservoir model. The reservoir model can handle transient, multiphase flow and it includes a flow model and a thermal model. The calculation of the reservoir flow model is based on the streamline simulation and the calculation of reservoir thermal model is based on the finite difference method. The reservoir thermal model includes thermal expansion and viscous dissipation heating which can reflect small temperature changes caused by pressure difference. We combine the reservoir model with a horizontal well flow and temperature model as the forward model. Based on this forward model, by making the forward calculated temperature and pressure match the observed data, we can inverse temperature and pressure data to downhole flow rate profiles. Two commonly used inversion methods, Levenberg- Marquardt method and Marcov chain Monte Carlo method, are discussed in the study. Field applications illustrate the feasibility of using this model to interpret the field measured data and assist production optimization. The reservoir model also reveals the relationship between temperature behavior and reservoir permeability characteristic. The measured temperature information can help us to characterize a reservoir when the reservoir modeling is done only with limited information. The transient temperature information can be used in horizontal well optimization by controlling the flow rate until favorite temperature distribution is achieved. With temperature feedback and inflow control valves (ICVs), we developed a procedure of using DTS data to optimize horizontal well performance. The synthetic examples show that this method is useful at a certain level of temperature resolution and data noise.Item Intra-meander groundwater-surface water interactions in a losing experimental stream(2010-08) Nowinski, John David; Cardenas, Meinhard Bayani, 1977-; Sharp, John M.; Bennett, Philip C.Groundwater-surface water interactions between streams and shallow alluvial aquifers can significantly affect their thermal and chemical regimes and thus are critical for effective management of water resources and riparian ecosystems. Of particular significance is the hyporheic zone, an area delineated by subsurface flow paths that begin and end in surface water bodies. Although detailed work has examined hyporheic flow in the vertical dimension, some studies have suggested that the drop in a stream’s elevation as it flows downstream can laterally extend the hyporheic zone. This study examines intra-meander hyporheic flow using extensive field measurements in a full-scale experimental stream-aquifer system. Synoptic head measurements from 2008 and 2009 and a lithium tracer test were conducted to determine the extent and nature of hyporheic flow within the meander. Permeability was measured and sediment cores were analyzed from 2008 to 2009 to assess aquifer properties. Finally, transient head and temperature measurements were collected during flooding events to assess the sensitivity of intra-meander hyporheic flow and temperature to stream discharge. Results verify that hyporheic flow through meanders occurs, but show that it is sensitive to whether a stream is gaining or losing water to the subsurface overall. In addition, permeability and core grain size results indicate moderate heterogeneity in permeability can occur in aquifers composed of relatively uniform sediment. Results also demonstrate that permeability in alluvial aquifers can evolve through time. Such evolution may be driven by groundwater flow, which transports fine particles from areas where porosity and permeability are relatively high and deposits them where they are relatively low, thus creating a positive feedback loop. Finally, measurements during flooding indicate that steady-state hyporheic flow and the thermal regime within the aquifer are largely insensitive to stream discharge. Together, these results expand upon previous field studies of intra-meander hyporheic flow and verify previous modeling work, although they demonstrate a level of complexity within these systems that should be considered in future work.Item Joint Inversion of Production and Temperature Data Illuminates Vertical Permeability Distribution in Deep Reservoirs(2012-10-19) Zhang, ZhishuaiCharacterization of connectivity in compartmentalized deepwater Gulf of Mexico (GoM) reservoirs is an outstanding challenge of the industry that can significantly impact the development planning and recovery from these assets. In these deep formations, temperature gradient can be quite significant and temperature data can provide valuable information about field connectivity, vertical fluid displacement, and permeability distribution in the vertical direction. In this paper, we examine the importance of temperature data by integrating production and temperature data jointly and individually and conclude that including the temperature data in history matching of deep GoM reservoirs can increase the resolution of reservoir permeability distribution map in the vertical direction. To illustrate the importance of temperature measurements, we use a coupled heat and fluid flow transport model to predict the heat and fluid transport in the reservoir. Using this model we ran a series of data integration studies including: 1) integration of production data alone, 2) integration of temperature data alone, and 3) joint integration of production and temperature data. For data integration, we applied four algorithms: Maximum A-Posteriori (MAP), Randomized Maximum Likelihood (RML), Sparsity Regularized Reconstruction and Sparsity Regularized RML methods. The RML and Sparsity Regularized RML approaches were used because they allow for uncertainty quantification and estimation of reservoir heterogeneity at a higher resolution. We also investigated the sensitivity of temperature and production data to the distribution of permeability, which showed that while production data primarily resolved the distribution of permeability in the horizontal direction, the temperature data did not display much sensitivity to permeability in the horizontal extent of the reservoir. The results of these experiments were compelling in that they clearly illuminated the role of temperature data in enhancing the resolution of reservoir permeability maps with depth. We present several experiments that clearly illustrate and support the conclusions of this study.Item Laboratory Study to Identify the Impact of Fracture Design Parameters over the Final Fracture Conductivity Using the Dynamic Fracture Conductivity Test Procedure(2011-08-08) Pieve La Rosa, Andres EduardoThis investigation carried out the analysis of fracture conductivity in a tight reservoir using laboratory experiments, by applying the procedure known as the dynamic fracture conductivity test. Considering the large number of experiments necessary to evaluate the effect of each parameter and the possible interaction of their combinations, the schedules of experiments were planned using a fractional factorial design. This design is used during the initial stage of studies to identify and discharge those factors that have little or no effect. Finally, the most important factors can then be studied in more detail during subsequent experiments. The objectives of this investigation were focused on identifying the effect of formation parameters such as closure stress, and temperature and fracture fluid parameters such as proppant loading over the final conductivity of a hydraulic fracture treatment. With the purpose of estimating the relation between fracture conductivity and the design parameters, two series of experiments were performed. The first set of experiments estimated the effects of the aliases parameters. The isolated effect of each independent parameter was obtained after the culmination of the second set of experiments. The preliminary test results indicated that the parameters with major negative effect over the final conductivity were closure stress and temperature. Some additional results show that proppant distribution had a considerable role over the final fracture conductivity when a low proppant concentration was used. Channels and void spaces in the proppant pack were detected on these cases improving the conductivity of the fracture, by creating paths of high permeability. It was observed that with experiments at temperatures around 250 degrees F, the unbroken gel dried up creating permeable scales that resulted in a significant loss in conductivity. The results of this investigation demonstrated that dynamic fracture conductivity test procedure is an excellent tool to more accurately represent the effects of design parameters over the fracture conductivity. These results are also the first step in the development of a statistical model that can be used to predict dynamic fracture conductivity.Item Novel methods of characterizing phthalate emissions and their fate and transport in residential indoor environments(2014-12) Liang, Yirui; Xu, Ying (Assistant professor)Phthalates have been used pervasively as plasticizers in consumer products and building materials. These semi-volatile organic compounds (SVOCs) are ubiquitous in indoor environments, redistributing from their original sources to indoor air, and subsequently to all interior surfaces. Because they partition strongly to surfaces, most phthalates persist for years after the source is removed. Biomonitoring data based on blood and urine testing provide direct evidence of the universal and significant human exposure to phthalates, which may result in serious adverse health effects. However, effective strategies to limit exposures to phthalates remain hamstrung by our poor understanding of their sources and fate and transport in indoor environments. The goal of this research is to explicitly elucidate the fundamental mechanisms governing emission, transport, and human exposure associated with phthalates in indoor environments. The specific research objectives are to 1) develop a novel, rapid, small-chamber method to determine the key parameters that control phthalate emissions and characterize the emissions; 2) investigate the influences of temperature, air flow rate, and surface sorption on phthalate emissions via a series of controlled tests in small and large chambers; 3) develop and validate a new indoor fate and transport model for phthalates with consideration of particle dynamics and its effects on emission and sorption. This research, which connects emission measurements to chemical transport and exposure assessment, will explicitly elucidate the fundamental mechanisms governing emission, transport, and human exposure associated with phthalates in indoor environments.Item Post-harvest high heat treatment on grapes and the effects on wine quality relating compounds(2012-12) Zhang, Yanmei; Trela, Brent; Hellman, Edward W.; Mansouri, HosseinThis research evaluated simulated accumulated summer temperature conditions in grape shipping containers during transportation from vineyard to winery in Texas. Temperature treatments were applied to five batches of destemmed grapes comprised of three batches of red varieties and two batches of white varieties. After 0 to 15 hr treatments, the berries were processed and fermented to wines in micro scale. Phenolic constituents important to wine quality sensory perception, including total phenolics, anthocyanins, tannins and polymeric pigments, as well as color intensity, hue and standard wine parameters were quantified to evaluate the effects of heat at post-harvest stage on the subsequent wines. The results indicate that long distance transportation of berries in Texas may result in high phenolic extraction and elevated browning in white wines, while red wines tended to change red color intensity, tannin concentrations and red pigment profiles, which might not affect red wines sensorily. Heat treatment did not affect pH, titratable acidity, ethanol concentrations, browning, total phenolic concentrations or anthocyanin concentrations compared to the wines made from the low heat treated berries. The composition of phenolic constituents in red wines is relatively stable after the heat treatment before vinification.Item Real-Time Evaluation of Stimulation and Diversion in Horizontal Wells(2012-02-14) Tabatabaei Bafruei, Seyed MohammadOptimum fluid placement is crucial for successful acid stimulation treatments of long horizontal wells where there is a broad variation of reservoir properties along the wellbore. Various methods have been developed and applied in the field to determine acid placement and the effectiveness of diversion process, but determining the injection profile during a course of matrix acidizing still remains as a challenge. Recently distributed temperature sensing technology (DTS) has enabled us to observe dynamic temperature profiles along a horizontal wellbore during acid treatments. Quantitative interpretation of dynamic temperature data can provide us with an invaluable tool to assess the effectiveness of the treatment as well as optimize the treatment through on-the-fly modification of the treatment parameters such as volume, injection rate and diversion method. In this study we first discuss how fluid placement can be quantified using dynamic temperature data. A mathematical model has been developed to simulate the temperature behavior along horizontal wellbores during and shortly after acid treatments. This model couples a wellbore and a near-wellbore thermal model considering the effect of both mass and heat transfer between the wellbore and the formation. The model accounts for all significant thermal processes involved during a treatment, including heat of reaction, conduction, convection. Then a fast and reliable inversion procedure is used to interpret the acid distribution profiles from the measured temperature profiles. We extend the real-time monitoring and evaluation of the acid stimulation treatment in horizontal wells to calculate the evolving skin factor as a function of time and location along the wellbore. As the skin factor is a reflection of the injectivity, it will indicate directly if the acid stimulation is effective and if diversion is successful. The approach to monitor the evolving skin along the lateral is to use a proper pressure transient model to calculate skin factor by integrating the inversion results of the temperature data (acid injection profile) with either surface or bottomhole injection pressure. This method can help engineers to optimize an acid stimulation in the field.