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A 42-year-old woman with idiopathic Raynaud's phenomenon developed localized necrosis of her fingertip after using an aerosol can of spray hair color. Laboratory measurements indicated that while such products did not achieve freezing temperatures, they did become cold enough to potentially produce vasospasm. Patients with Raynaud's phenomenon should be cautioned that use of some aerosol products may result in a cold induced injury.

It is well-known that the performance of the CS process is enhanced by increasing the process gas stagnation temperature, as this increases the gas velocity, and thus the particle velocity (kinetic energy). However, the influence of the initial substrate, coating, and particle impact temperatures on the CS process performance is still a topic that has barely been studied. This work focuses on establishing in a more systematic way how the initial substrate, coating, and particle impact temperatures affect the CS process performance by decoupling these three variables from the general spray parameters, namely the gas stagnation temperature. This decoupling is of crucial importance if one wants to be able to study the effect of each temperature and this approach has never been reported anywhere so far. In this work, two feedstock powder materials are used: pure aluminum and Inconel 718. The substrate material selected is Ti-6Al-4V. Therefore, the observations provided in this thesis are valid for the deposition of aluminum-on-Ti-6Al-4V and Inconel718-on-Ti-6Al-4V. To increase and control the initial substrate and coating temperatures while ensuring proper decoupling of other spray parameters, an induction heating system is used with the CS process. To control the initial particle temperature, independently from the gas stagnation temperature, powder preheater units are used. The powder is fed in the diverging section of the nozzle to avoid the uncontrollable heating usually observed by feeding the powder in the converging section. Single-particle impact testing and splat adhesion strength testing are carried out to evaluate the effect of the initial substrate temperature on individual particles. This is investigated using pure aluminum as the feedstock powder material. A finite element modeling is also carried out to complement the experimental results. The influence of the initial substrate temperature on the deposition process is quantified by measuring the deposition efficiency and coating porosity values. Micro-hardness testing and adhesion strength testing are used to characterized the as-sprayed coating mechanical properties. To study the influence of the coating temperature on the CS process performance, both powders, pure aluminum and Inconel 718, are used. The role of the coating temperature on the CS process is assessed by measuring the deposition efficiency and coating porosity values for the deposition of both powders. Micro-hardness, adhesion, and tensile strength measurements of the pure aluminum coatings is carried out. For the Inconel 718 coatings, only micro-hardness testing is conducted. To characterize the influence of the particle impact temperature on the CS process, Inconel 718 is used. The particle impact temperature is predicted using a computational fluid dynamics model. Deposition efficiency, coating porosity values, and micro-hardness testing are used to characterize the influence of the particle impact temperature on the CS process. The results in this thesis provide a path to optimize the CS process performance based on the influence of the initial substrate, coating, and particle impact temperatures. This work also demonstrates that other variables, such as particle impact velocity and feedstock powder material hardness, must also be considered to optimize the CS process performance through the use of different temperatures.

In individuals living with obesity, adipose tissue aids in reducing (H_loss) and also serves as a heat storage compartment. Moreover, lean body mass, which has a higher H_prod than adipose tissue plays a crucial role in energy production and thermoregulation. The extent of resistance to the cold remains underexplored in this population, and it is important to understand these responses given the global obesity rise and its health implications. This study aimed to quantify how various body anthropometric variations affected thermal responses in individuals living with obesity during acute compensable cold exposure. A liquid-conditioned suit, connected to a temperature-controlled water circulating bath set at 10°C, was used for 90 min to elicit a compensable cold response in these individuals. Validated methods regarding subjective thermal comfort and sensations, skin temperature (T_skin; °C), heat production (H_prod; kJ ⋅min⁻¹), metabolic fuel selection and shivering intensity were recorded to determine the effect of obesity (and muscle and fat mass) on thermogenic and thermal responses. Our study revealed that individuals with obesity, like their lean counterparts, manifest an increased H_prod during cold exposure by 1.7 ± 1.3 kJ ⋅min⁻¹. However, this increase was observed to be lesser in magnitude among individuals living with obesity compared to lean ones. We also explored the source of fuel during cold exposure and found that carbohydrate and lipid oxidation collectively accounted for a significant proportion of H_prod, with lipid oxidation dominating at 61%, and carbohydrates at 21%. Regarding muscle activity, it was observed that a decrease in T_skin incited an increase in shivering. However, similar to the metabolic responses, shivering in this cohort was much less pronounced than in lean individuals. The study opens avenues for further research, addressing the implications of repeated cold exposure and different lengths, temperatures, or modalities on individuals living with obesity.

Due to increasing power demands and decreasing component size, thermal management has become the bottleneck for many power electronic applications. The aerospace industry has focused on reducing weight, operating temperature, and pumping power of power converters since these will limit an aircrafts' range and load carrying capacity. This paper outlines a tool created in MATLAB to automate the cold plate design process for DC-DC converters (or similar applications). The tool incorporates a genetic algorithm to fi nd the optimal aligned or staggered pin fi n confi guration that maintains the devices below their critical junction temperature while reducing the system's overall weight and pressure drop. Utilizing this MATLAB design tool, a cold plate was designed, manufactured, and tested. The convection coefficient calculated within MATLAB (via empirical correlations) was veri fed using simplifi ed CFD simulations within 5% of each other. The same CFD setup, boundary condition types, and methodology are then applied for the full-sized prototype cold plate simulations. These simulations were then validated using the experimental results. For all cases, the percentage error between the simulated convection coefficient values (CFD) and the experimental results was less than 12%. The experiments' measured surface temperature and pressure drop errors were less than 8% of the predicted CFD results. Therefore, the MATLAB tool and its correlations/calculations could be veri fied (via CFD) and validated (experimentally) based on good agreement between the CFD and the experimental results. This three-pronged approach (analytical calculations, CFD simulations, and experimental validation) is an effective and robust method to solve heat transfer problems. Overall, with the framework outlined in this thesis, a complete cold plate design can now be completed in weeks instead of months. This streamlined approach will save companies signifi cant time and money in the design and simulation phases, making this tool a valuable addition to the current literature available. / Thesis / Master of Applied Science (MASc)

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The objective of this study was to evaluate the sensitivity of instantaneous latent heat flux (LE) estimation from Surface Energy Balance Algorithm for Land (SEBAL) by changing hot/cold pixel selections. The SEBAL model was programed in a Matlab environment and applied to Lower Fox Watershed in northeast Illinois using two Landsat 5 Thematic Mapper images acquired in summer 2006. Unlike most previous studies where hot/cold pixel were manually selected by image analysts, we emphasized an automated hot/cold pixel selection based on land cover map, normalized difference vegetation index (NDVI) map, and land surface temperature (LST) map. Various combinations of hot/cold pixels were automatically selected along the LST gradient. The LE estimations were then validated against ground-based eddy covariance observation. Results show that the LE estimations from SEBAL were sensitive to both hot and cold pixel selections and tend to be more sensitive to cold pixel selection. The absolute percentage difference (APD) of LE estimation compared with field observation data can range from 0.67% to 67.2% by varying hot and cold pixel combinations. The location of hot/cold pixels appears to have minor impact on SEBAL LE estimation. The LE estimation become acceptable (APD < 10%) when using the hot/cold pixels with a slightly higher/lower LST than LST extremes from the study area. This study provides insights into hot/cold pixel selection and the sensitivity of SEBAL-based LE estimation. Future research on SEBAL ET estimation should focus on enhancing automated hot/cold pixel selection algorithm to improve the model's operational use. / Master of Science

Thesis (Ph. D.)--University of California, San Diego, 2008. / Title from first page of PDF file (viewed December 16, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 206-219).

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Atsparumas šalčiui ir ištvermingumas žiemą – pagrindiniai veiksniai, lemiantys augalų geografinį pasiskirstymą. Be to, šie veiksniai turi didžiulę įtaką kultūrinių augalų derlingumui. Braškės, kurios yra tarp svarbiausių uoginių augalų pasaulyje ir Lietuvoje, stipriai pašąla esant nepastoviai sniego dangai, vis dažniau pasitaikančiomis permainingomis žiemojimo sąlygomis. Nepakankamas braškių ištvermingumas žiemą, aiškių kriterijų, kurie leistų per trumpesnį nei kelių metų laikotarpį atrinkti ištvermingas veisles nebuvimas, apsunkina naujų, adaptyvių, derlingų, kokybiškomis uogomis, braškių veislių sukūrimą ir introdukciją. Atsparumo šalčiui mechanizmai intensyviai tirti naudojant modelinius augalus, tačiau žinių apie žiemojančių kultūrinių augalų, kurių įvairovė labai didelė, ištvermingumo žiemą mechanizmus ir jo genetinį reguliavimą labai trūksta. Atsparių šalčiui augalų atrankai vykdyti reikalingos žinios apie augalų užsigrūdinimą, apie atsparumą šalčiui lemiančius veiksnius ir juos kontroliuojančius genus. Tiriant augalus kontroliuojamomis sąlygomis in vitro, galima ištirti atskirų veiksnių įtaką užsigrūdinimui ir atsparumui šalčiui, atsiribojant nuo, neišvengiamo natūraliomis sąlygomis, daugelio įvairių veiksnių poveikio. Braškių užsigrūdinimas ir atsparumas šalčiui svarbūs ne vien tik atrankai. Genetinių išteklių išsaugojimas ateities kartoms - svarbus šiuolaikinės biologijos uždavinys. Didelių kolekcijų išsaugojimą palengvina ir sąnaudas sumažina, augalų laikymas... [toliau žr. visą tekstą] / Cold hardiness and resistance in winter are key factors determining the geographical distribution of plants. In addition, these factors have a huge impact on harvest of cultural plants. Strawberries, which are among the most important berry plants in the world and in Lithuania, are vulnerable to cold because of unstable snow cover, which is more and more often occurring during variable wintering conditions. Insufficient resistance of strawberries in winter, absence of clear criteria, which enable to select the most resistant varieties during a shorter time than the few year period, impedes the development and introduction of new, adaptive, fertile, and of high-quality berries strawberry cultivars. The mechanisms of cold hardiness were intensively investigated using model plants. However, there is a lack of knowledge about the genetic regulation mechanisms of winterhardiness of cultural plants. For the selection of resistant to cold plants, the knowledge about plants cold acclimation and factors determining cold resistance and controlling genes is necessary. Investigating the plants under controlled conditions in vitro, it is possible to investigate the influence of individual factors on acclimation and cold hardiness by disassociating from the influence of many different factors, which is unavoidable under natural conditions. The cold acclimation and cold hardiness of strawberries are important not only for breeding. Preservation of plant genetic resources for future... [to full text]