Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 194 for “"Temperature difference"”.
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A study of the controllability of air movements in predominantly naturally ventilated houses.
… doorway openings, due to the effects of temperature difference and combined temperature and pressure difference. The method of measurement uses tracer gases which are injected into spaces and their growths and decays are monitored. These concentration histories, when suitably analysed, …
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Breaking the thermo-mechanical coupling of thermoelectric materials : determining the viability of a thermoelectric generator
Thermoelectric power generators (TEGs) convert a temperature difference into electricity. This temperature difference can be created from waste heat. Since up to 50% [1] of US industrial energy input is lost as waste heat, an economical means of recovering waste heat and converting it into useful …
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Comparative study of advanced heat pumps
… rejection or heat absorption space. A cool side temperature difference between 0 and 20{dollar}\sp\circ{dollar}C is investigated, and this temperature difference accounts for both thermal resistance and cooling load. An outside temperature ranging between 35{dollar}\sp\circ{dollar}C and …
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Condensing heat transfer within horizontal tubes
… was to study the effect of vapor velocity, temperature difference and fluid properties upon the heat transfer coefficient of a vapor condensing within a horizontal tube. Condensing heat transfer coefficients for propane were measured over a wide range of conditions. The data would not …
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Design of a single orifice pulse tube refrigerator through the development of a first-order model
… pulse tube refrigerator, but that the predicted temperature difference was approximately five times higher than the measured temperature difference. It is believed that the model can be improved with provisions for flow choking as well as warnings for behavior outside of the accepted operating …
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Using thermal imaging data to explore behaviour in a critically endangered frog species, Craugastor ranoides
… environmental conditions to regulate their body temperature and physiological functions. Thermal imaging can be used as a non-invasive method to study thermal behaviour. Thermal images measure the surface temperature of species as well as surrounding substrate. The present study used Craugastor …
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Heat transfer rates for filmwise, dropwise, and superhydrophobic condensation on silicon substrates
… as much as 50 kW/m 2 less than FWC at the same temperature difference, representing a 25% reduction. However, the SHC heat transfer rates remain above those of FWC by as much as 50 kW/m² at the same temperature difference, representing a 20% improvement. These studies suggest that SHC may be a …
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Theoretical, Experimental, and Numerical Investigations Into Laser Repair of Adhered MEMS Structures
A MEMS temperature sensor based on the buckling of fixed-fixed beams due to thermal expansion is designed, fabricated, and tested. Difficulties from fabrication including residual stress, and limited temporal and spatial resolution of the imaging system hindered the device performance, but …
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The effect of a knurled heat transfer surface upon pool nucleate boiling of normal pentane
… boiled was normal pentane at its saturation temperature and a pressure of 760 millimeters mercury.</p> <p>For some of the knurled surfaces the temperature difference required to produce a given heat flux was found to be less than half that required for an unknurled control surface. For all of …
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Laser (Cooling) Refrigeration in Erbium Based Solid State Materials
… energy levels that could bring obtainable temperatures two orders of magnitude lower. Erbium transitions of interest for cooling fall in the near IR region (0.87 microns and 1.5 microns). Lasers for one of these transitions, in the 1.5 micron region, are well developed for communication and …
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Modeling of the Evaporation and Condensation of Zeotropic Refrigerant Mixtures in Horizontal Annular Flow
… cause circumferential and axial composition and temperature gradients in the liquid film when zeotropic mixtures undergo evaporation and condensation. Heat transfer in mixtures is shown to be less than the ideal limit due to mass transfer resistance in the vapor. The mass transfer resistance …
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Thermal Coefficients and their Relation to the Onsacer Coefficients
… which describes the behavior of a system due to differences within the system or between the system and its surroundings. These differences give rise to thermodynamic forces which can cause flows of quantities such as charge and energy. One example of such a force is the temperature gradient due …
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Comparing the Efficiency of Heterogeneous and Homogeneous Data Center Workloads
… include processor utilization as well as the temperatures of both the hot and cold aisles during the entirety of the experimental procedure.</p> <p>The experimental research hopes to show that the balanced workload has a positive effect on the temperature difference observed across the hot and …
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Calculation of gas-wall heat transfer from pressure and volume data for spaces with inflow and outflow
… condition can be out of phase with the temperature difference. For studies with closed piston-cylinder gas springs, this heat transfer phase shift has been successfully predicted with the use of a complex Nusselt number. Since a complex,number has both a magnitude and a phase, a complex …
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Convection in Corrugated Slots
… The buoyancy forces associated with the temperature difference between isothermal plates drive the natural convection. This temperature difference is expressed in terms of the Rayleigh number Ra and the analysis is limited to its subcritical values where no secondary motion takes place in …
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Design, prototyping, and testing of an apparatus for establishing a linear temperature gradient in experimental fish tanks
… the ability to select their surrounding water temperature in order to react to a simulated viral infection with an optimized immune response. Although countless immunology studies have been performed with zebrafish to date, their validity came into question in early 2013 when it was …
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The investigation of the effects of temperature, pump pressure and the size of the pipe on the critical Reynolds number and the study of the variation of heat transmission film coefficient of the viscous fluid in the transition region
… A = total cooling surface, in sq ft ΔT = mean temperature difference between the oil and the pipe wall, in °F The rate of heat flow is calculated from the temperature drop and the rate of flow of oil. The cooling surface is obtained by multiplying the actual inside periphery of 3/8 pipe by the …
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An SEM surface study of nucleate pool boiling heat transfer to saturated liquid nitrogen reduced pressures from 0.1 to 0.9
… surfaces yielding higher heat flux values. The temperature difference at burnout was found to be a function of both surface chemistry and roughness. Some existing correlations for both nucleate boiling and maximum heat fluxes were examined and shown to inadequately predict the data, primarily …
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The Structure and Intensity of Winter Mesoscale Lake -Effect Circulations Associated With an Isolated Lake
… a dimensionless quantity comprised of lake-air temperature difference, fetch distance, air temperature, and boundary layer height to improve its predictive capability. The intensity index: (1) accounts for the relative contributions of variables fundamental to the lake-effect system, (2) …
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Exergy analysis of a Stirling cycle
… in using Stirling engines in low to medium temperature solar thermal applications, and for waste heat recovery. To develop high-performance engines that are also economically viable, advanced mathematical models that accurately predict performance and give insight into the different loss …
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