Thesis (M.S.)--University of Wisconsin--Madison, 1971. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The diploma thesis is focusing on research of possible damage mechanism of U-tubes in a heat exchanger placed within a gas waste incinerator unit in a factory dealing with chemicals manufacturing. In the first phase of the research, in which a thermo – hydraulic calculation is being made, a specialized software tool HTRI Xchanger Suite® v6.00 is used. Using the software it is possible to simulate certain operational conditions in which the heat exchanger operates. The output from the first phase of the solution is to obtain a set of temperatures of the tube material throughout the length of the tubes. These data are consequently used in the second phase of the analysis. The second phase of the analysis is dealing with thermal lenght dilatation differences assessment between tubes in the tube bundle as a predected reason of oversize tension formed in tube material and damage following afterwards. Conclusions of the calculation made in the second phase of the analysis are then checked by calculation via ANSYS Workbench 11.

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N/A / Thesis / Master of Science (MS)

Due to concerns for the environmental and sociological implications of hydrocarbon use, farmers have begun to examine renewable energies and conservation techniques for crop production. Historically, most of the energy needs for climate control in tunnel systems have been met via passive heating, with fossil fuels occasionally providing a supplementary heat source. Five heating techniques were examined for kale (Brassica oleracea) and summer squash (Cucurbita pepo) season extension. Treatments consisted of a low tunnel heated by a solar-powered electrical strip placed under a water tube, a low tunnel heated by a passively heated water tube, a low tunnel heated by an earth-to-air heat-exchange tube, a traditional low tunnel, and a control unprotected plot. Aerogel blankets and SolaWrap® floating covers were also examined as floating covers to protect crops from cold temperatures. To predict energy output, the USDA ARS Virtual Grower was compared against data from the tunneled treatments. Treatments were tested in fall 2020 and spring 2021 with data was collected for air, soil, and tube temperature (ºC), crop growing degree - days, squash seed germination and kale height (cm) and dry biomass (g). The electrically heated water tube produced the highest mean spring day air (28.2 ºC), fall soil temperatures (14.6ºC), thermal tube temperature for the 24 - hour, day and night timeframe for both seasons. However, for soil, the passively heated water tube showed the best results amongst the two seasons heating the soil surface at a 24 - hour mean of 13.8 ºC for fall and 18.2 ºC for spring. The earth tube warmed tunnel air in spring with a mean internal 24 - hour temperature of 19.5 ºC for spring against the 15.7 ºC recorded during fall, while providing the highest mean minimum temperatures. For growing degree-days, all treatments outperformed the uncovered control, with the earth tube treatment performing better for the kale degree day 24 - hour mean of 9.1 for fall 2020 against its spring output of 12.6. The electric heated thermal tube and earth tube improved germination of summer squash during the fall 2020 trial, while the passive tube positively influenced germination during the spring 2021. No differences were observed amongst the treatments in either season for final kale canopy height or dry biomass, though the earth tube displayed the highest range and means. However, kale plants were taller and had greater dry biomass when grown in spring compared to fall. Solar powered heated water tube, earth tube and passively heated water tube accelerated kale development in spring. For the floating cover trial, while the SolaWrap® had the highest mean 24-hour temperature 21.0 ºC, the aerogel blanket showed temperature parity in the daily minimum and night temperatures, and both mean and cumulative kale and summer squash growing degree-days. The Virtual Grower program produced a significantly higher mean and summative kJ output compared to collected by factoring climate, solar radiation, and wind speeds. In the fall study, light limitations arrested kale and squash production rather than a freezing event with treatments being more effective in spring due to increasing daylength. The most effective treatment for spring was the solar powered heated water tube because it provided a first harvestable kale and summer squash at 2-3 whole weeks before conventional spring harvesting, while the earth tube showed a better performance in degree-day accumulation for the cool season kale and warm season squash for the fall extension trial, each having a 24 - hour mean of 9.1 and 12.6. / Master of Science in Life Sciences / Due to both environmental and cost concerns regarding hydrocarbons, farmers have been searching for alternative heating methods to extend the crop season production. At the Virginia Tech Urban Horticulture Center three trials occurred to examine such methods. The first one occurred in spring 2020 and fall 2021 and examined non – hydrocarbon heating methods for low – tunnel systems. Said techniques were a control exposed plot, a simple low – tunnel system, a tunnel that utilized an earth tube, a low – tunnel that had a water tube and a low – tunnel that had a water tube that was warmed by a heating tape powered by solar panels. Crops grown were kale (Brassica oleracea) and summer squash (Cucurbita pepo). Data for this section included mean overall 24 – hour, mean 24 – hour minimum and 24 – hour maximum air temperatures along with mean 24 – hour soil temperatures (oC) with growing degree – days, seed germination, mean seed germination time and kale end season canopy height (cm) and dry biomass (g). The second trial compared the use of aerogels and SolaWrap® as a floating cover against both each other and an exposed plot by looking at their overall 24 – hour, mean 24 – hour minimum and 24 – hour maximum air temperatures. The third section of the trial looked at how the USDA – ARS Virtual Grower Program predicted the required heating output against manual equations from the data gathered in the first part of the trial. For the first section, the best performing systems regarding temperature were the solar powered heating tape due to its ability to store solar energy as well as the earth tube for utilizing a heat source not limited to the presence of the sun. This temperature performance also positively influenced crop germination and development, though the simple water tube also showed better performance. The second section of the trial showed that while the SolaWrap® had a higher overall 24 – hour mean and 24 – hour maximum temperature, the aerogel showed a higher heat retention by having both an equal and higher mean 24 – hour minimum temperature. For the third section, the Virtual Grower showed a higher kJ output requirements due to its ability to factor in location and past climactic activity, something that the manual calculations couldn't do. This trial showed that alternative heating methods, materials and calculations can enhance and extend production, though additional research on both costs and technique optimization are required.

In May of 2006, the Hrubec group suddenly began to observe neural tube defects (NTDs) in embryos of untreated control mice. Unintentional exposure to a teratogenic agent in tap water was identified as the cause. We aimed to identify the contaminant, but first we demonstrated that the NTDs were pathological being present on both gestational day 9 and 10. We also found that a second species, rats, developed NTDs when exposed to tap waters. Disinfection by-products (DBPs) arise when natural organic matter in municipal water sources reacts with disinfectants used in the water treatment process. Purge and trap gas chromatography-mass spectrometry (PT GC-MS) and animal exposure studies were used to determine if the teratogenic contaminant was a DBP. Since the distribution pattern of DBPs did not match the distribution pattern of NTDs, we concluded that a DBP was not likely to be responsible for the observed malformations. Pharmaceuticals and personal care products have emerged as ubiquitous contaminants of ground and surface waters, and have been detected in drinking water. In order to analyze for these compounds, we submitted different water samples to a commercial water analysis lab (AXYS Analytical Services, Sidney, BC, Canada). Several pharmaceuticals were identified in a number of samples, including a known teratogenic drug used to treat mood disorders and seizures: carbamazepine. Further analysis for carbamazepine was conducted in-house. Carbamazepine was found in several ground, surface, and tap waters, at various concentrations. To establish whether or not carbamazepine was responsible for NTDs in our mice, we conducted 2 dosing studies. Carbamazepine was provided to mice at concentrations detected in tap water, as well as approximately 2 x and 1000 x that concentration. Both studies found no significant differences in NTD rates among the dose groups. As no dose effect was observed, we concluded that CBZ was not directly responsible for the malformations. The identity of the teratogenic contaminant is not known at this time, but is unlikely to be a DBP or low concentrations of the pharmaceutical carbamazepine. / Master of Science

A new dynamic model is presented for piezoelectric tube actuators commonly used in high-precision instruments. The model captures coupling between motions in all three axes such as bending motion due to a supposedly pure extension of the actuator. Both hysteresis and creep phenomena are included in the overall actuator model permitting modeling nonlinear sensitivity in the voltage to displacement response. Experimental data on hysteresis and creep are presented to support the modeling. Experiments and model predictions show that due to coupling a voltage Vz corresponding to vertical displacement will produce lateral displacement that acts as a disturbance to the main lateral response. The resonance frequency for the lateral dynamics is inherently lower than that of the longitudinal dynamics. Therefore, Vz is expected to contain frequencies that may excite the lateral resonance. Accordingly, this out of bandwidth disturbance will not be well compensated for either in open or closed loop control of the actuator. In order to preserve performance in open loop actuator control and stability and performance in closed loop control, a large reduction in the bandwidth of vertical motion would be required to avoid exciting the first bending mode. / Singapore-MIT Alliance (SMA)

<p>Over-inflation of an endotracheal tube (ETT) cuff may lead to tracheal necrosis, whereas under- inflation increases the risk of pulmonary aspiration. The objectives of this 2-phase study were to 1) identify the frequency of abnormal ETT cuff inflation in anesthetized dogs, 2) evaluate ETT cuff inflation with 3 devices (regular syringe, Tru-CuffTM syringe, AG Cuffill syringe) in achieving proper cuff pressure (20-30 cmH2O). Dogs undergoing general anesthesia at Purdue Veterinary Medicine Teaching Hospital (PVMTH) were included. The standard operating procedure (SOP) of PVMTH was used for ETT size selection and cuff inflation. The results of objective 1 showed that 50 of the 80 dogs required ETT cuff inflation. Among these 50 dogs, only 14% had proper cuff inflation; 76% of the cuffs were over-inflated and 10% were under-inflated. For objective 2, 90 dogs were equally assigned to the 3 devices for ETT cuff inflation and cuff pressure was assessed with an aneroid manometer. The results showed that 80% of the ETT cuffs were over-inflated with the regular syringe, whereas only 6.7% and 3.3% ETT cuffs were over-inflated with the Tru-CuffTM and AG Cuffill syringes, respectively. The AG Cuffill syringe treatment group had a significantly higher percentage of proper inflated ETT cuffs (86.7%; both p < 0.05) compared to the other two groups (regular [3.3%]; Tru-CuffTM [50%]). We concluded that there was a high frequency of improper ETT cuff inflation when using SOP coupled with a regular syringe. The use of an AG Cuffill syringe significantly reduced improper ETT cuff inflation.</p>