Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / by Christopher Lloyd Hoxie. / Ph.D.

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Nuclear Engineering. / Microfiche copy available in Archives and Science. / Includes bibliographical references. / M.S.

Thesis. 1978. Nucl.E.--Massachusetts Institute of Technology. Dept. of Nuclear Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / Nucl.E.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE / Includes bibliographical references. / by Bruce William Hagemeier. / M.S.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 247-249. / by Wee Tee Loh. / Ph.D.

京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第17914号 / エネ博第286号 / 新制||エネ||59(附属図書館) / 30734 / 京都大学大学院エネルギー科学研究科エネルギー変換科学専攻 / (主査)教授 木村 晃彦, 教授 星出 敏彦, 教授 小西 哲之 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM

Burrs are rough protrusions that form along the edge of a component during processing and are commonly produced during machining. Generally, the presence and severity of a burr directly impacts the final part quality. Thus, burrs need to be removed in subsequent processes to avoid injury when handling a part and/or negatively impacting the part's functionality. The size, shape, and nature of the attachment of the burr to the cutting edge are highly dependent on the material, tooling, and process parameters used during machining. This research aimed to develop two new approaches to minimize and/or eliminate burr formation during the drilling of ductile materials. The first new method outlined in this thesis relates to injecting materials in different forms at high pressures under the workpiece on the side from which the drilling tool exits to support the drilling thrust force and thereby minimize exit burr formation. The second method introduced a novel technique for designing and testing highly effective step drills based on the workpiece material and cutting parameters, using commercial drills. Testing the two approaches showed promising results for producing comparatively smaller exit burrs. / Thesis / Master of Applied Science (MASc)

Pressurized hot water and DTPA-Sorbitol are two relatively new soil boron (B) extraction methods with potential to replace the cumbersome hot water extraction. The objective of this research is to produce data in support of acceptance or rejection of these two alternative B extractions. The three soil tests were used to extract B from samples of calcareous sand and silt loam and limed, loamy fine sand treated with 10 levels of B and incubated for 7 and 28 d. As B application increased so did extractable B with each extraction method. High correlations (r of 0.977 to 0.999) were observed between extractable B and rate of B application with all three methods. Hot water generally extracted the least and pressurized hot water the most B regardless of soil type, rate of application or duration of incubation. Greenhouse and field experiments were conducted on one limed acid and two alkaline soils naturally low in B to test alfalfa response to B fertilizer. Values from the three soil extraction methods were correlated to yield, B tissue concentration and total B removal of alfalfa. In greenhouse studies with varying levels of soil applied B, highly significant relationships exist between extractable soil B and both tissue B concentration and total B removal. Correlations between yield and extractable soil B were impossible to obtain because of a lack of alfalfa yield responses to applied boron. All three methods accurately predict plant B tissue concentrations and total B removal. The field experiment produced a significant positive relationship between total alfalfa yield and extractable B using hot water and pressurized hot water extractions, but not using DTPA-Sorbitol. The results observed in this research support pressurized hot water extraction as the better of the two alternatives to replace hot water extraction in a broad range of soil types.

This work evaluates the relative significance of forces determining the motion of a pulverized coal particle under conditions representative of a pressurized oxy-coal combustor. The gravity force and surface forces of drag, fluid stress, added mass, and Basset history are discussed and appropriate forms of these force equations are chosen, with a consideration of spherical and non-spherical drag and the Basset history kernel. Studies from the literature that emphasize specific forces are used to validate the implementation of the force equations and correlations. Modeling is based on time-averaged, one-dimensional motion of a single non-reacting particle along the centerline of a round, turbulent jet. The numerical methodology employed for solving the particle equation of motion is described in detail, and simulated particle motion is compared to experimental and high-fidelity simulations from the literature. Comparisons show the numerical methodology performs adequately relative to higher fidelity simulations and experimental test cases for one-dimensional, time-invariant conditions. To assess the effect of pressure on particle forces and motion under different conditions, simulation cases are run for particle diameters of 20 μm, 50 μm, 125 μm, gas temperatures of 300 K and 1500 K, and gas pressures of 1.01325 bar, 2 bar, 5 bar, 10 bar, 20 bar, 40 bar. Simulations are conducted over a 0.75-m length in a simplified environment representative of the pressurized oxy-coal (POC) combustor at Brigham Young University. Results show that all surface forces examined can be locally significant at high gas pressures when particle and gas velocity differences, i.e., particle Reynolds numbers, are greatest. The following trends are found for the behavior of surface forces in simplified, POC combustor simulations: 1) The quasi-steady drag force is always significant, though it's relative contribution to particle motion decreases as particles traverse regions with significant fluid velocity gradients or significant values for the substantial derivative of fluid velocity. Furthermore, quasi-steady drag is the only surface force that is significant throughout the entirety of a particle's trajectory. The relative contribution of the drag force decreases with increasing gas pressure. 2) The impact of the fluid stress force on particle motion increases with increasing gas pressure and particle size. The fluid stress force can be locally important for all of the particles sizes when at a gas temperature of 300 K and elevated pressure, as particles traverse regions with significant substantial derivatives of fluid velocity. The local impact of the fluid stress force is largely negligible at 1500 K, except for the case of the largest particle at the greatest pressure. 3) The behavior of the added mass force largely mirrors that of the fluid stress force, though the added mass force is generally of lesser magnitude. Therefore, the added mass force can be locally important for all of the particles sizes when at a gas temperature of 300 K and elevated pressure, as particles traverse regions with significant substantial derivatives of fluid velocity. The added mass force is generally the least significant of the analyzed surface forces. 4) The Basset history force is locally significant for all cases where the particles are traversing regions with significant fluid velocity gradients. The impact of the Basset history force on particle motion increases with increasing gas pressure and particle size, while decreasing as gas temperature increases.

A new method of power production, called pressurized oxy-fuel combustion, burns coal with CO2 and oxygen, rather than air, bringing us closer to the end goal of developing zero emission coal-fired utility boilers. However, high-pressure, high-temperature systems such as these are under-studied, and their behavior is difficult to measure. An accurate model for previously untested conditions requires data for validation. The heat release profile of flames and their radiative intensity is one of the key data sets required for model validation of an oxy-coal combustion system. A radiometer can be used to obtain the necessary radiative heat flux data. However, several studies show significant measurement errors of past radiometer designs. This work focuses on developing a narrow angle radiometer that can be used to describe radiative heat transfer from a pressurized oxy-coal flame. The sensitivity of the instrument to outside environmental influences is thoroughly examined, making it possible to obtain the axial radiative heat flux profile of the flame in a 100kW pressurized facility by accurately converting the measured quantities into radiative heat flux. Design aspects of the radiometer are chosen to improve the accuracy of radiative heat flux measurements as well as conform to the physical constraints of the 100kW pressurized facility. The radiometer is built with a 0.079-inch aperture, an 8.63-inch probe internally coated with high emissivity coating, four baffles spaced evenly down the length of the probe, no optic lens, a thermopile as the sensor, argon purge gas, and a water-cooled jacket. The radiometer has a viewing angle of 1.33 degrees. The instrument is calibrated with a black body radiator, and these calibration data are used in combination with radiation models to convert the radiometer signal in mV to radiative heat flux in kW/m2. Environmental factors affecting accuracy are studied. The results of the calibration data show that the radiometer measurements will produce a calculated heat flux that is accurate to within 5.98E-04 kW/m2.