The machining of a new alloy often presents a challenge. While useful assumptions can be drawn from materials of similar properties, there will always be unpredictable outcomes. Titanium alloys have been employed in the aerospace industry due to their high mechanical properties and good strength-to-weight ratio. Ti-64 (Ti-6Al-4V) was the standard choice until recently, when Ti-555.3 (Ti-5Al-5V-5Mo-3Cr) began to take its place. Ti-555.3 has improved resistance to fatigue and higher mechanical properties compared to Ti-64 and is able to maintain its strength when exposed to high temperatures, which warrants its acceptance for many applications. However, its chemical reactivity, low thermal conductivity and high mechanical properties are known to cause challenges when cutting this alloy. Making use of both experimental procedures and computational resources, this work presents a comparison between these two aerospace alloys under different process conditions, setting the ground for further academic development and optimization strategies. Determining that these alloys are substantially different from a machinability standpoint (lower tool life, abrasion & chipping as dominant wear mechanisms and nonuniform chip formation for Ti555.3 versus Ti-64). Based on this further investigation should be carried out for optimal tooling selection to improve the machining of Ti555.3. / Thesis / Master of Applied Science (MASc)

Encephalitozoon cuniculi is a zoonotic protozoan parasite in the phylum Microspora that has been shown to naturally infect several host species, including humans, rabbits and dogs. Currently, serological diagnosis of infection is made using the immunofluorescense assay (IFA) or enzyme-linked immunosorbent assay (ELISA). Although these methods are sensitive and reliable, there are several drawbacks to both tests. Cross-reactivity between other Encephalitozoon species is common, and specialized equipment is required for IFA and ELISA. Most wildlife species are unable to be tested using these methods, because species-specific antibodies are required. One goal of this work was to develop a new serological test for diagnosing E. cuniculi infection that would be more practical for use in small veterinary and medical clinics. The effectiveness of the agglutination test was examined in CD-1 and C3H/He mice infected with E. cuniculi or one of 2 other Encephalitozoon species. The results indicate that the agglutination test is 86% sensitive and 98% specific for E. cuniculi, with limited cross-reactivity to E. intestinalis. The test is fast and easy to conduct, and requires no specialized equipment or species-specific antibodies. Recent reports of microsporidial DNA in crop irrigation waters suggest that unpasteurized juice products may be contaminated with E. cuniculi. High pressure processing (HPP) is an effective means of eliminating bacteria and extending the shelf life of products while maintaining the sensory features of food and beverages. The effect of HPP on the in vitro infectivity of E. cuniculi spores was examined. Spores were exposed to between 140 and 550 MPa for 1 min, and then spores were loaded onto cell culture flasks or were kept for examination by transmission electron microscopy (TEM). Spores treated with between 200 and 275 MPa showed reduction in infectivity. Following treatment of 345 MPa or more, spores were unable to infect host cells. No morphologic changes were observed in pressure-treated spores using TEM. The effect of disinfectants on in vitro infectivity of E. cuniculi spores was also examined. Spores of E. cuniculi were exposed to several dilutions of commercial bleach, HiTor and Roccal, and 70% ethanol for 10 minutes and then loaded onto Hs68 cells. The results of this study showed that all concentrations of disinfectants tested were lethal to E. cuniculi spores. Encephalitozoon cuniculi spores are more sensitive to disinfectants than are coccidian oocysts and other parasite cysts. / Master of Science

Juices have been implicated in numerous foodborne outbreaks over the last couple of decades. The FDA requires a 5-log10 reduction in juice products, which is most commonly achieved through pasteurization. However, pasteurization deteriorates some sensorial properties and nutritive value. Coconut water (CW; classified as a juice), is rapidly gaining popularity increasing over 300% since 2005. CW has not been implicated in a microbial outbreak, but is thermally processed to achieve the required 5-log10 CFU/ml reduction, which results in negative organoleptic properties. The objectives of this study are to determine whether E. coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes can grow in CW, and evaluate the use of High Pressure Processing (HPP) to reduce populations of these bacteria in CW. The three pathogens were inoculated separately into CW and bacterial populations were enumerated over 24 hours. All three bacteria reached at least 8-log10 CFU/ml after 24 hours, which was not significantly different from the control (TSB). CW was then inoculated with each pathogen and processed using HPP (400, 5000, or 600 MPa) for 120 seconds. The D-glucose, D-fructose, sucrose, and phenol oxidase levels in the CW were assessed before and after treatments. Following processing, the pathogens were enumerated from the CW. All three pathogens were reduced by more than 6-log10 CFU/ml following treatments of 500 and 600 MPa, enough to achieve the mandatory 5-log CFu/m reduction. There were no significant changes in the D-glucose, D-fructose, sucrose, and phenol oxidase activity after any of the treatments. / Master of Science in Life Sciences

Critical heat flux (CHF) and post-CHF are two critical phenomena in light water-cooled nuclear power plants regarding safety. Even though the general trends of CHF and post- CHF are known, the exact mechanisms are still unknown. To better understand CHF and post-CHF, experimental flow boiling facilities are constructed around the world. However, these facilities are limited in their experimental conditions and spatial resolution necessary to advance our understanding of two-phase heat transfer. Previous rod surface measurements were collected with thermocouples to measure CHF location and temperature excursion, yet thermocouples provide limited spatial resolution, which leads to significant uncertainties in the CHF prediction. On the other hand, optical fiber temperature sensors can measure the temperature and the CHF propagation with high spatial resolution. Also, the capability of the optical fiber at high temperatures has been proven in previous studies. The current study aims to apply optical fiber at high-pressure and high mass fluxes. The high-Pressure HIgh-temperature annuLUS flow (PHILUS) facility was designed to provide desired working conditions in the test section that uses optical fiber temperature sensors. The PHILUS test section has a length of 1320 mm, with 1000 mm of heated length. The working conditions of the PHILUS are up to 18 MPa, temperatures up to 357◦C, and coolant mass flux from 500 to 3700 kg/m2s. The main components of the loop are a steam separator, two heat exchangers (a condenser and a cooler), a bladder-type accumulator, two bypass lines, and a high-pressure pump. Coolant-Boiling in Rod Arrays-Two Fluids (COBRA-TF) code was used to design the CHF and post-CHF experiments to be performed at the PHILUS facility. / Master of Science / A nuclear power plant produces heat which is transferred from the reactor core through the coolant. The coolant water flows through the reactor core to safely transport the heat that ultimately is used to produce electrical energy. If the balance between the power produced by fission and the energy removed by the coolant is changed, it can lead to potential damage to the reactor core. The maximum heat transfer rate occurs at the point where a vapor blanket covers the surface of the fuel cladding. At this point, known as Critical Heat Flux (CHF), the surface temperature drastically increases. To better understand and better predict the CHF, experimental facilities are needed. Even though there are several facilities worldwide, most of them have limited working conditions and measurement capabilities. Past experiments used thermocouples to measure the surface temperature with a very small spatial resolution, which causes very large uncertainties in the CHF and post-CHF predictions. On the other hand, optical fiber sensors can be used to measure temperature with very high spatial resolution. The high-Pressure HIgh-temperature annuLUS flow (PHILUS) facility was designed in this work to apply optical fibers in the measurement of the rod surface temperature and simulations were performed to show its advantages. The working conditions of the PHILUS are comparable to commercial pressurized water reactors.

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

The mineral prehnite, Ca2(Al,Fe,Mn)(AlSi3O10)(OH)2, is a layered structure consisting of double-sheets of (Al,Si)O4 and SiO4 tetrahedra alternating with single sheets of AlO4(OH)2 octahedra. To understand the ordering in the structure and differences between various samples of prehnite, single-crystal X-ray diffraction data at ambient conditions were collected on four single crystals of prehnite from different localities. The positions of the H atoms have been determined for the first time, from a combination of X-ray and neutron diffraction data. The equation of state and high-pressure behavior of prehnite have been investigated using single-crystal X-ray diffraction up to 9.75(3) GPa. A second-order Birch–Murnaghan equation of state fit to the isothermal P-V data to 8.7 GPa yields a bulk modulus, K = 109.29(18) GPa. Structural data collected at high pressures indicate that the structure compresses uniformly. Above 8.7 GPa there is additional softening of the volume and the b-axis related to polyhedral tilting. However, the average structure is maintained across the transition. Ambient and high-pressure Raman and synchrotron infrared spectra were collected from 1 bar to 20 GPa. Raman spectra measured at ambient conditions of four prehnite crystals with different compositions confirmed that there are no structural changes with different compositions. High-pressure results showed the majority of modes shift to higher frequencies (in a smooth, linear fashion) with increasing pressure. The greatest change in the spectra is the softening of the modes in the OH-stretching region above 9 GPa, thought to be related to the polyhedral tilting around the H environment. / Master of Science

The motivation for the determination of the viscosity of polymer solutions in dense fluids at the critical polymer concentration stems from the need to understand the factors that influence the time scale of phase separation in systems that undergo spinodal decomposition upon a pressure quench. In a recent investigation of PDMS + CO₂ and PE + n-pentane where molecular weights of the polymers and the critical polymer concentrations were comparable, significant differences were observed in the time evolution of new phase growth. Among the reasons that contribute to the difference in phase separation kinetics is the viscosity of the solutions. This thesis has been carried out to experimentally demonstrate the differences in viscosities of solutions at their critical polymer concentration. Specifically, the thesis focused on the high-pressure density and viscosity of solutions of poly(dimethylsiloxane) (Mw = 93,700, Mw/Mn = 2.99) in supercritical carbon dioxide and of polyethylene (Mw = 121,000, Mw/Mn = 4.3) in near-critical n-pentane. The measurements have been carried out at the critical polymer concentrations, which is 5.5 wt % for solution of PDMS in CO2 and 5.75 wt % for solution of PE in n-pentane. For PDMS + CO₂ system, the measurements were conducted at 55, 70, 85 and 100 oC and pressures up to 50 MPa. For PE + n-pentane system, the measurements were conducted at 140 and 150 °C and again up to 50 MPa. All measurements were conducted in the one-phase homogenous regions. At these temperatures and pressures, the viscosities were observed to be in the range from 0.14 mPa.s to 0.22 mPa.s for PDMS + CO₂, and from 2.3 mPa.s to 4.6 mPa.s for PE + n-pentane systems. In both systems the viscosities increase with pressure and decrease with temperature. The temperature and pressure dependence could be described by Arrhenius type relationships in terms of flow activation energy (E#) and flow activation volume (V#) parameters. The flow activation energies in PDMS + CO₂ system were about 7 kJ/mol compared to about 18 kJ/mol for the PE + n-pentane system. The activation volumes were in the range 40-64 cm3/mol for PDMS + CO₂ system and 65-75 cm3/mol for the PE + n-pentane solution. The higher values of E# and V# represent the higher sensitivity of viscosity to temperature and pressure changes in the PE + n-pentane system. The viscosity data could also be correlated in terms of density using free-volume based Doolittle type equations. Density is shown to be an effective scaling parameter to describe T/P dependency of viscosity. The closed packed volumes suggested from density correlations were found to be around 0.33 cm³/g for the PDMS and 0.48 cm3/g for the PE systems. Comparison of the viscosity data in these systems with the data on the kinetics of pressure-induced phase separation confirms that the slower kinetics in the PE + n-pentane stems from the higher viscosity in this solution compared to the PDMS + CO₂ system, despite the similarity in the molecular weight of the polymer and the critical polymer concentrations. These viscosity and density measurements were conducted in a special falling-body type viscometer. In the course of this thesis a more reliable procedure for determining the terminal velocity of the falling sinker was implemented. This is based on the precise and more complete description of the position of the sinker with time with the aid of a set of linear variable differential transformers (LVDTs). The design of the new arrangement and procedure for terminal velocity determination and calibration procedures for the viscometer are also presented. The densities and viscosities are determined with an accuracy of ± 1 % and ± 5 % or better, respectively. / Master of Science

No description available.

In order to exploit unconventional gas and estimate carbon dioxide storage potential in shale formations and coal seams, two key questions need to be initially answered: 1) What is the total gas-in-place (GIP) in the subsurface reservoirs? 2) What is the exact ratio between bulk gas content and adsorbed gas content? Both questions require precise estimation of adsorbed phase capacity of gases (methane and carbon dioxide) and their adsorption behavior in shale and coal. This dissertation therefore analyzes adsorption isotherms, thermodynamics, and kinetics properties of methane and carbon dioxide in shale and coal based on experimental results to provide preliminary answers to both questions. It was found that the dual-site Langmuir model can describe both methane and carbon dioxide adsorption isotherms in shale and coal under high pressure and high temperature conditions (up to 27 MPa and 355.15K). This allows for accurate estimation of the true methane and carbon dioxide GIP content and the relative quantity of adsorbed phases of gases at in situ temperatures and pressures representative of deep shale formations and coal seams. The concept of a deep shale gas reservoir is then proposed to optimize shale gas development methodology based on the successful application of the model for methane adsorption in shale. Based on the dual-site Langmuir model, the isosteric heat of adsorption is calculated analytically by considering both the real gas behavior and the adsorbed phase under high pressure, both of which are ignored in the classic Clausius–Clapeyron approximation. It was also found that the isosteric heat of adsorption in Henry's pressure region is independent of temperature and can serve as a quantified index to evaluate the methane adsorption affinity on coal. In order to understand the dynamic response of gas adsorption in coal for carbon sequestration, both gas adsorption kinetics and pore structure of coal are investigated. The pseudo-second order model is applied to simulate the adsorption kinetics of carbon dioxide in coals under different pressures. Coal particle size effects on pore characterization of coal and carbon dioxide and nitrogen ad/desorption behavior in coal was also investigated. / Ph. D. / Shale gas is natural gas that is found trapped within subsurface shale formations, and the in-situ pressure and temperature of shale formations can go up to 27MPa and 86℃. Shale gas, the main component of which is methane, mainly consists of adsorbed phase and free compressed gas in shale formations. The adsorbed phase accounts for 20-85% of the total gas-in-place resource. Thus, the estimation of amount of methane adsorbed in shale under in-situ conditions are extremely important for determining the total gas-in-place quantity and the working life of a shale gas production well and its economic viability. This work provides a method for accurate estimation of the shale gas-in-place resource under in-situ shale formation conditions. The method is based on laboratory methane adsorption test data in shale at high pressure (up to 27MPa) and high temperature (up to 82℃) conditions. According to this method, it was found that for depths greater than 1000 m (> 15 MPa) in the subsurface, the shale gas resources have historically been significantly overestimated. For Longmaxi shale (2500 – 3000 m in depth), classical approaches overestimate the GIP by up to 35%. The ratio of the adsorbed phase compared to the free gas has been significantly underestimated. Shale gas production follows pressure depletion of shale formations. The pressure depletion process allows methane in the adsorbed phase to become free gas, which is known as the physical desorption process. Desorption is an endothermic process while adsorption is an exothermic process, both of them are reversible. Thus, the heat transfer process during shale gas production requires a thermodynamic analysis of methane adsorption in shale. This work investigates the isosteric heat of adsorption for methane in shale by considering both the real gas behavior and the volume effect of the adsorbed phase, not previously considered for methane in shale. The temperature dependence as well as the uptake dependence of the isosteric heat can be readily investigated by the applied method. This study lays the foundation for future investigations of the thermodynamics and heat transfer characteristics of the interaction between high pressure methane and shale. This work also investigates gas adsorption kinetics properties in coal and the particle size effect on pore characterization of coal using the gas adsorption approach. Results show that particle size of coal samples can significantly influence the sorption behavior of gas in coal, which finally affects pore characterization of coal. It is difficult to characterize the pore structure of coal using only one coal particle size. Carbon dioxide adsorption kinetics in coal, which can be modelled by the pseudo-second order model, is a combination of both bulk diffusion-controlled and surface interaction-controlled processes; the former dominates the initial stage while the latter controls the majority of the overall process.

No description available.