M.S.

Dewatering fine coal is needed in many applications but has remained a great challenge. The hydrophobic-hydrophilic separation (HHS) method is a powerful technology to address this problem. However, organic solvents in solvent-coal slurries produced during HHS must be recovered for the method to be economically viable. Here, the experimental studies of recovering solvents from pentane-coal and hexane-coal slurries by combining liquid-solid filtration and in-situ vaporization and removing the solvent by a carrier gas (i.e., drying) are reported. The filtration behaviors are studied under different solid mass loading and filtration pressure. It is shown that using pressure filtration driven by 20 psig nitrogen, over 95% of solvents by mass in the slurries can be recovered, and filtration cakes can be formed in 60 s. The drying behavior was studied using nitrogen and steam at different temperatures and pressures. It is shown that residual solvents in filtration cakes can be reduced below 1400 ppm within 10 s by 15 psig steam superheated to 150C, while other parameter combinations are far less effective in removing solvents. Physical processes involved in drying and the structure of solvent-laden filtration cakes are analyzed in light of these results. / Master of Science / Coal particles below a certain size are discarded to waste tailing ponds as there is no economically viable method for processing them. However, a new process called hydrophobic-hydrophilic separation offers a solution to this problem. A hydrophobic solvent is used to displace water from a coal-water slurry, and it is then easier and cheaper to filter and dry this new coal-solvent slurry. In this work experimental studies of recovering solvents from pentane-coal and hexane-coal slurries by combining filtration and drying are reported. The filtration behaviors are studied under different solid mass loading and filtration pressures. It is shown that using pressure filtration driven by 20 psig nitrogen, over 95% of solvents by mass in the slurry can be recovered, and filtration cakes can be formed in 60 s. The drying behavior was studied using nitrogen and steam at different temperatures and pressures to evaporate any remaining solvents. It is shown that the remaining solvents in filtration cakes can be reduced below 1400 ppm within 10 s by using 15 psig steam superheated to 150C as a drying medium, while other parameter combinations are far less effective in removing solvents. Physical processes involved in drying and the structure of solvent-laden filtration cakes are analyzed in light of these results.

Within the educational community, there is a growing shift towards the development of essential skills, emphasizing process-skills over mastery of content. This shift is mirrored in the rapid changes in workplace-related technology, outpacing the creativity and flexibility of current graduates. Makerspaces and related technology education approaches have been increasingly implemented to offer students opportunities for developing these desired skills. Parallel to this effort, students who receive special education services but access the general education curriculum continue to lag behind the general education population in high-stakes testing, graduation-rates, and long-term employment outcomes. Remediation-based services often preclude students receiving services from exposure to technology- or other enrichment-based educational opportunities. The initial phase of this exploratory case study focused on the impacts of a technology-based enrichment club on a small group of special education learners. Through this proof-of-concept study, it became apparent that adult participants across stakeholder groups were showing evidence of transformative learning through their experiences with the club. The follow-up study, therefore, focused on changes in adult perceptions and/or practices resulting from these experiences, as evidenced through the Nerstrom Transformative Learning Model (2014). Following exposure, interviews were conducted with participating cosponsors, school-based educational leaders, and guest presenters from technical fields. These interviews were analyzed for both commonly identified and group-specific themes. Results suggest that experiences with the club challenged various assumptions held by participants, often leading to new perspectives on special education practices and students who receive services. These results suggest that potential shifts are a function of how many established perspective-based obstacles these challenged and reformed assumptions can address. Recommendations for future research include replication, extension beyond a club setting, and further exploration of identified themes, as well as investigating the deeper implications of obstacles to transformative learning. / Doctor of Education / Within the educational community, there is a growing shift towards the development of essential skills, emphasizing process-skills over mastery of content. This shift is mirrored in the rapid changes in workplace-related technology, outpacing the creativity and flexibility of current graduates. Makerspaces and related technology education approaches have been increasingly implemented to offer students opportunities for developing these desired skills. Parallel to this effort, students who receive special education services but access the general education curriculum continue to lag behind the general education population in high-stakes testing, graduation-rates, and long-term employment outcomes. Remediation-based services often preclude students receiving services from exposure to technology- or other enrichment-based educational opportunities. The initial phase of this exploratory case study focused on the impacts of a technology-based enrichment club on a small group of special education learners. Through this proof-of-concept study, it became apparent that adult participants across stakeholder groups were showing evidence of transformative learning through their experiences with the club. The follow-up study, therefore, focused on changes in adult perceptions and/or practices resulting from these experiences, as evidenced through the Nerstrom Transformative Learning Model (2014). Following exposure, interviews were conducted with participating cosponsors, school-based educational leaders, and guest presenters from technical fields. These interviews were analyzed for both commonly identified and group-specific themes. Results suggest that experiences with the club challenged various assumptions held by participants, often leading to new perspectives on special education practices and students who receive services. These results suggest that potential shifts are a function of how many established perspective-based obstacles these challenged and reformed assumptions can address. Recommendations for future research include replication, extension beyond a club setting, and further exploration of identified themes, as well as investigating the deeper implications of obstacles to transformative learning.

Salmonella enterica has been associated with several outbreaks due to consumption of low water activity foods including spices. Consequently, to improve microbiological quality, spices are commonly treated before ultimately reaching consumers. These processes may result in sub-lethal injury to cells, which can lead to an underestimation of microbial populations when plating on selective media. Sub-lethally injured cells are difficult to enumerate due to reduced ability to grow on selective microbiological media. Poor recovery of sub-lethally-injured cells may obscure process validation results and lead to overestimation of process effect. Therefore, this work was performed to determine the influence of agar overlay and media supplementation methods on the recovery of Salmonella from steam and ethylene oxide treated peppercorns and cumin seeds. Traditional agar overlay allowed recovery of significantly more Salmonella (p < 0.05) from inoculated peppercorns treated with steam (65.5C, 15 sec.) than selective media (XLT4) or solid agar overlay. Additional supplementation of the TSA base to contain 3,3'-thiodipropionic acid further improved Salmonella recovery from steam treated peppercorns (p < 0.05). For peppercorns and cumin seeds subjected to ethylene oxide, neither sodium pyruvate + yeast extract, 3,3'-thiodipropionic acid, glycerophosphate, ATP, nor magnesium enhanced recovery compared to overlay alone but both methods recovered significantly higher numbers than XLT-4 alone (p < 0.05) for both cumin seeds and peppercorns. / Master of Science in Life Sciences

The VPI plant has met the load situation of the 1935-1936 heating season with a small margin of capacity. Should it have been considered necessary, as a matter of policy, to carry reserve through this heating season, 20,751 pounds per hour of steam capacity would have been lacking. To meet the maximum possible hourly-load anticipated for the 1936- 1937 heating season, it would require an increase in the present capacity of the plant of 11 percent. Considering the carrying of ample reserve, an increase of 117 percent would be necessary. In that the load has reached and passed the most economical output from the standpoint of fuel consumption, forcing of present equipment will now involve economic losses that may be used to offset the costs of a new boiler installation. The load duration curve shown in Fig. 11 will be valuable in economic studies of this type. In conclusion, the authors suggest the possibility of using capacity now latent in the plant. The building of a storage place to make dry coal available tor No.4 boiler would release approximately 6,700 pounds per hour of latent steam capacity. Further gains could be made by forcing boilers 1, 2, and 3 to higher ratings with excess air during the peak hours, while the use of a higher grade bituminous coal during the heavy heating season would also show substantial gains in capacity. / Master of Science

After reviewing all available literature on heat transfer to superheated steam at high temperatures and pressures, it was concluded that further investigation of this problem would be of value. The thesis was concerned with the derivation of three heat transfer film coefficient equations and their related error equations. The three equations thus derived were not used to determine the value of the heat transfer film coefficient. No experimentation was performed to obtain the necessary data required by the three equations for calculating the heat transfer film coefficient value. Instead an error analysis was made of the film coefficient equations using the derived error equations. Prediction of the most accurate film coefficient equation was made based on results obtained from this analysis. Recommendations for the test apparatus and arrangement, test section design, and experimental procedure were advanced based on the error analysis results. No attempt was made in the thesis to develop an experimental heat transfer film coefficient similar to the equations found in the reviewed literature. / Master of Science

Tests were conducted in the Lubrication Laboratory of the Virginia Polytechnic Institute to study the effect of several metals on the deterioration of steam-turbine oils. A special test apparatus was constructed and three commercial turbine oils were tested in the presence of 14 different metal and metal combination. Included in this group of metals were five bearing metals, several metals now extensively used in turbine lubricating systems, and several metals that are not at present used in turbine oiling systems. Oxidation of the oils was accomplished by heating the oil in glass containers at 275°F for 200 hours, in the presence of the metals. The oil samples were then subjected to laboratory inspections to determine the extent of oxidation. It was found that in the case of oil A copper, lead and the copper-lead combination were increasingly effective in increasing the viscosity and acidity. Brass, copper, and copper-lead were increasingly effective in promoting sludge formation. With oil B copper, lead, and the copper-lead combination were increasingly effective in promoting sludge formation and increasing the viscosity. Steel, lead and the copper-lead combination were increasingly effective in producing acidity. Copper, metal No. 9, and the copper-lead combination were increasingly effective in increasing the viscosity of oil C. Copper, metal Ho. 5, and copper-lead produced acidity in increasing amounts. Aluminum, zinc, and cooper were increasingly effective in promoting sludge formation. Tin showed the least effect on solidity in the case of all three oil. It caused the lowest sludge formation with oils A and B and was low with oil C. The viscosity of oil A was least affected by metal No. 6, of oil B by metal No. 8, end of oil C by steel. / Master of Science

In 1939, a fifth steam generating unit was added to the Virginia Polytechnic Institute Central Heating and Power Plant. This unit was an E. Keeler, 500 horsepower, three drum, bent water tube type boiler, fired by a Westinghouse five retort underfeed stoker with link-grate section. Soon after the installation of this unit, W.F. Diamond and C.F. DeBush made an investigation to determine the effects of various fuel bed depths on the efficiency of the unity. Approximately 6 1/2 years have elapsed since their investigation was completed. No other tests have been conducted on the unit up to now. Consequently, its performance characteristics and maximum thermal efficiency at the present time are not accurately known. Even though Diamond and DeBusk made their investigation to determine the effect of various depths of fuel bed on the performance of the unit, the optimum percentage C0₂, and the range of load for maximum thermal efficiency, there is at the present time, a decided difference of opinion among the power plant personnel regarding these facts. It is contemplated that a sixth unit will shortly be installed in the V.P.I. Power Plant. Therefore, it is necessary to know what maximum continuous load and what peak loads for short periods of time the No. five until can be expected to carry now that it has been in operation for almost seven years. During the past two or three years, the operation of the stoker on the No. five unit has not been satisfactory. Large coke trees (see Discussion of Results, page 67) are formed in the fuel bed at the front end of the stoker where coal enters the furnace. There coke trees ride on the fuel bed as it moves from the front end of the furnace to the ash discharge orifice (see Fig 18), and are only partially consumed during combustion. When they reach the ash discharge orifice clogging results. This necessitates cleaning the orifice and ash discharge plates with a firing iron. Actual cases have been known to occur when a complete loss of load and a 50 per cent reduction in steam pressure have resulted from the clogging of the orifice. / Master of Science

The development and evaluation of a fuel cell test stand incorporating various methods for controlling the temperature and humidity of fuel cell reactants is described. The test stand is capable of accurately metering gas flows, controlling the temperature and humidity of the gases, and delivering the gases to the fuel cell in a safe manner. Additionally, the test stand can measure the voltage and current produced by the fuel cell during operation. Two test stands were constructed and evaluated, one using steam injection for fuel cell stacks and the other using flash evaporation for individual fuel cells. Both test stands were shown to provide adequate control at the upper end of the design range. The flash evaporation test apparatus was used to investigate the effect of inlet gas humidity on fuel cell performance. The results from this investigation showed that, for a fuel cell and reactant temperature of 75°C, the best performance was achieved with a high relative humidity (90%RH) for the hydrogen and a comparatively low relative humidity (60%) for the air. / Master of Science

Mat conditions of temperature and gas pressure were measured in three locations for one conventional and four steam-injection press schedules used in the laboratory scale manufacture of aspen (Populus grandidentata and Populus tremuloides) flakeboard. Two resins, phenol formaldehyde and polymeric MDI, were used. Steam-injection press schedules varied from low steam input to high steam input by adjusting steam pressure, steam time, and the density range for steam-injection during press closing. Steam-injection rapidly raises mat core temperatures as compared to conventional pressing. Temperature and gas pressure were positively correlated with the amount of steam input. Flakeboard strength and dimensional stability properties were tested. Steam-injection pressing produced panels with superior dimensional stability as compared to conventional pressing. The high steam press schedule produced internal bond and shear strengths equal to the conventional press schedule for phenol formaldehyde. Medium steam press schedules produced superior internal bond and shear strengths to the conventional press schedule for polymeric MDI. The conventional press schedule produced superior static bending MOR strengths for both resins. A fluorescence microscope was interfaced with a digitizing image analysis system to measure resin penetration area on flakes recovered from inside of the mat. Wood anatomy was found to be the dominating factor in creating high variablity in resin penetration area measurements, as differences could not be detected due to the press schedules or resin type. / Master of Science