The cabin environment of a commercial aircraft, including cabin layout and the quality of air supply, is crucial to the airline operators. These aspects directly affect the passengers’ experience and willing to travel. This aim of this thesis is to design the cabin layout for flying wing aircraft as part of cabin environment work, followed by the air quality work, which is to understand what effect the ECS can have in terms of cabin air contamination. The project, initially, focuses on the cabin layout, including passenger cabin configuration, seat arrangement and its own size due to the top requirements, of a conventional aircraft and further into that of a flying wing aircraft. The cabin work in respect of aircraft conceptual design is discussed and conducted by comparing different design approaches. Before the evaluation of cabin air quality, an overall examination of the main ECS components involved in the contaminants access will be carried on and, therefore, attempt to discover how these components influence the property of the concerned contaminants. By case study in the B767 ECS, there are some comments and discussions regarding the relationship between the cabin air contaminations and the passing by ambient environment. The thesis ends up with a conclusion explaining whether or not the contaminated air enters the occupants’ compartments on aircraft and proposing some approaches and engineering solutions to the continue research.

Misalignment in turbomachinery has been commonly known to produce twotimes- running-speed (2N) response. This project aimed to investigate the source of the 2N vibration response seen in misaligned vibrating machinery by simulating misalignment through a coupling. Three flexible disc-pack couplings (4-bolt, 6-bolt, and 8-bolt coupling) were modeled, and parallel and angular misalignments were simulated using a finite element program. The stiffness terms obtained from the coupling simulations had 1N, 2N, and 3N harmonic components. The 4-bolt coupling had large 1N reaction components under angular and parallel misalignment. The 6-bolt coupling model only had a 1N reaction component under angular misalignment, and both cases of parallel misalignment showed a strong 2N reaction component, larger than both the 1N and 3N components. The 8-bolt coupling model under angular misalignment produced large 1N reaction components. Under parallel misalignment, it produced 1N, 2N, and 3N components that were similar in magnitude. All the couplings behaved linearly in the range studied. A simple model predicted that the 2N frequency seen in the response is caused by the harmonic (1N) term in the stiffness. The amplitude of the 2N component in the response depends on the amplitude of the 1N term in the stiffness compared to the average value of the stiffness and the frequency ratio. The rotordynamic response of a parallel and angular misaligned system was completed in XLTRC2. When the frequency ratio was 0.5, the system response with the 4-bolt and 6-bolt coupling had a synchronous 1N component that was much larger than the 2N component. The response did not have a 2N component when the 8-bolt coupling was used but the response did have a 1.6N component that was considerably larger than the 1N component. When the frequency ratio was 2, the system response with the 4-bolt and 6-bolt coupling had a synchronous 1N component and a relatively small ½ frequency component. The response with the 8-bolt coupling had a 0.4N component that was larger than the 1N component. A 5-tilting pad journal bearing was also tested to better understand its behavior under misalignment because some experts attribute the 2N response to the nonlinear forces produced by bearings with high unit loads. The response of the 5-tilting pad bearing did not produce any 2N components while the bearing was subjected to unit loads of up to 34.5 bars.

This work shows that toughness (resistance) to fracture propagation is an inherent characteristic of cohesionless particulate materials, which is significant for understanding hydraulic fracturing in geotechnical, geological, and petroleum applications. We have developed experimental techniques to quantify the initiation and propagation of fluid-driven fractures in saturated particulate materials. The fracturing liquid is injected into particulate materials, where the fluid flow is localized in thin crack-like conduits. By analogy, we call them 'cracks' or 'hydraulic fractures'. Based on the laboratory observations and scale analysis, this work offers physical concepts to explain the observed phenomena. When a fracture propagates in a solid, new surfaces are created by breaking material bonds. Consequently, the material is in tension at the fracture tip. In contrast, all parts of the cohesionless particulate material (including the tip zone of hydraulic fracture) are likely to be in compression. In solid materials, the fluid front lags behind the front of the propagating fracture, while the lag zone is absent for fluid-driven fractures in cohesionless materials. The compressive stress state and the absence of the fluid lag are important characteristics of hydraulic fracturing in particulate materials with low, or no, cohesion. Our experimental results show that the primary factor affecting peak (initiation) pressure is the magnitude of the remote stresses. The morphology of fracture and fluid leak-off zone, however, changes significantly not only with stresses, but also with other parameters such as flow rate, fluid rheology, and permeability. Typical features of the observed fractures are multiple off-shots and the bluntness of the fracture tip. This suggests the importance of inelastic deformation in the process of fracture propagation in cohesionless materials. Similar to solid materials, fractures propagated perpendicular to the least compressive stress. However, peak injection pressures are significantly greater than the maximum principle stresses in the experiments. Further, by incorporating the dominate experimental parameters into dimensionless form; a reasonable power-law fit is achieved between a dimensionless peak injection pressure and dimensionless stress. Scaling indicates that there is a high pressure gradient in the leak-off zone in the direction normal to the fracture. Fluid pressure does not decrease considerably along the fracture, however, due to the relatively wide fracture aperture. This suggests that hydraulic fractures in unconsolidated materials propagate within the toughness-dominated regime. Furthermore, the theoretical model of toughness-dominated hydraulic fracturing can be matched to the experimental pressure-time dependences with only one fitting parameter. Scale analysis shows that large apertures at the fracture tip correspond to relatively large 'effective' fracture (surface) energy, which can be orders of magnitude greater than typical for hard rocks.

No description available.

Compost bedded pack (CBP) barn design and pack maintenance procedures vary considerably, making advising and problem-solving challenging. One objective of this research was to characterize herd performance and management practices employed by Kentucky CBP managers (42 farms and 47 CBP facilities). Producer satisfaction, changes in historical bulk-tank somatic cell count, and improvement in herd performance parameters after transitioning to a CBP barn support reported CBP barn system benefits. Daily milk production increased from before moving into the CBP barn to the second year after (29.3 ± 0.3 vs. 30.7 ± 0.3 kg, respectively; P < 0.05) for farms using the CBP barn as the primary housing facility (n = 8). Increasing stirring frequency, stirring depth, and ambient temperatures increased pack temperature. Increased drying rate decreased CBP moisture. Increased 20.3 cm depth CBP temperature and ambient temperatures improved cow hygiene. Mastitis-causing bacteria thrive in conditions similar to optimal composting bacteria conditions, making reduction of these bacteria difficult in an active composting environment. Producers must pay attention to other management areas where preventive measures can be employed. The New Dairy Housing Investment Analysis Dashboard provides users an interactive and flexible decision tool to make more informed facility investment decisions.

In the last few years researchers have more and more focussed on the possible use of cryotherapy as an acute and long term recovery facilitating technique by sportsmen and women. Barnette (2006) did, however, state that research supporting cryotherapy as a recovery facilitating technique, is not convincing and that the majority of research show that it has a negative impact on the recovery of subjects after exercise. It is against this background that the aim of the study was firstly to critically analyse the available literature of the past fifteen years (1992-2007) with regard to the study subject; die nature of the cryotherapy technique that was used as well as the findings with regards to the effects of these types of techniques on a wide variety of physiological variables, physical and motor performance; secondly, to provide guidelines for the use of cryotherapy as a recovery facilitating technique and thirdly to determine the effect of cryotherapy on the acute recovery of University netball players' lower leg muscles in an isokinetic ankle exercise. Firstly, it was shown that ice water immersion and ice pack application are the most common techniques that are used in cryotherapy studies. The results in the majority of articles indicated that cryotherapy had a non-significant acute effect on isokinetic, eccentric and concentric peak torque as well as time to reach peak torque and the angle at which the peak torque was reached; isometric, maximal and sub-maximal strength and accuracy of strength execution; normalized, average vertical ground reaction force as well as time of reaching peak power and vertical jump height; baseball pitching accuracy, proprioception, ankle joint range of movement, positioning and speed during execution of a movement; blood lactate removal and blood flow speed as well as muscle soreness after completion of an exercise. With regard to the long term effects of cryotherapy research showed that isotonic hand grip strength and endurance, plasma adrenaline, non-adrenaline, dopamine, renine, aldosterone, heart rate and blood pressure after 6 weeks; respiratory gas exchange ratio, heart rate, muscle glycogen concentration, plasma lactate, glucose and free fatty acids after 8 weeks or brachial artery cross-section and vascular endothelial growth factor after 4 weeks of exercise and cryotherapy did not experience any significant changes between the cryotherapy and control group. Other physical, motor performance and physiological variables did not show a certain trend with regards to the way they were affected by cryotherapy. In some cases variables were affected significantly negatively while the opposite was true in other cases where variables were significantly positively influenced. With regard to the results of the study on the acute recovery of University netball players' lower leg muscles due to cryotherapy, it was found that the acute recovery of only four isokinetic variables were significantly influenced (p = 0.05) by cryotherapy, namely: left leg relative total dorsiflexion work, average peak dorsiflexion torque, right dorsiflexion and plantar flexion endurance. The acute recovery of the first mentioned strength endurance related variable was significantly negatively influenced by the cryotherapy. In contrast with this result the acute recovery of the three last mentioned isokinetic muscle relative peak torque and endurance related variables were significantly positively influenced by the cryotherapy. The overall conclusion that can therefore be drawn from the above-mentioned results show that the majority of isokinetic plantar- and dorsiflexion torque variables (12 out of 16, 75%) as well as other physical, motor performance and physiological variables experience no significant effect with regards to acute and long term recovery due to cryotherapy. The research did, however, show that the effectiveness of cryotherapy was influenced by the adiposity thickness, nature of the cryotherapy application, type of medium that was used for cryotherapy application and the length of time during which cryotherapy was applied. The recommendation for the use of cryotherapy as a recovery facilitating technique can be summarised as follows: the temperature of the cryotherapy medium that is used, must vary between 5°C and 10°C; the duration of cryotherapy between 15 and 20 minutes; the most general application area: for ice water immersion - immersed up until the level of the gluteal fold or crista ileac and the whole arm or forearm; for ice pack application - on the thigh, ankle and peripheral of the shoulder; the most common and effective ice pack application is direct on the skin surface by means of a bag filled with between 500 g and 1 500 g cubic formed ice. For long term use more that 2 consecutive days of cryotherapy application is recommended. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2008.

In the last few years researchers have more and more focussed on the possible use of cryotherapy as an acute and long term recovery facilitating technique by sportsmen and women. Barnette (2006) did, however, state that research supporting cryotherapy as a recovery facilitating technique, is not convincing and that the majority of research show that it has a negative impact on the recovery of subjects after exercise. It is against this background that the aim of the study was firstly to critically analyse the available literature of the past fifteen years (1992-2007) with regard to the study subject; die nature of the cryotherapy technique that was used as well as the findings with regards to the effects of these types of techniques on a wide variety of physiological variables, physical and motor performance; secondly, to provide guidelines for the use of cryotherapy as a recovery facilitating technique and thirdly to determine the effect of cryotherapy on the acute recovery of University netball players' lower leg muscles in an isokinetic ankle exercise. Firstly, it was shown that ice water immersion and ice pack application are the most common techniques that are used in cryotherapy studies. The results in the majority of articles indicated that cryotherapy had a non-significant acute effect on isokinetic, eccentric and concentric peak torque as well as time to reach peak torque and the angle at which the peak torque was reached; isometric, maximal and sub-maximal strength and accuracy of strength execution; normalized, average vertical ground reaction force as well as time of reaching peak power and vertical jump height; baseball pitching accuracy, proprioception, ankle joint range of movement, positioning and speed during execution of a movement; blood lactate removal and blood flow speed as well as muscle soreness after completion of an exercise. With regard to the long term effects of cryotherapy research showed that isotonic hand grip strength and endurance, plasma adrenaline, non-adrenaline, dopamine, renine, aldosterone, heart rate and blood pressure after 6 weeks; respiratory gas exchange ratio, heart rate, muscle glycogen concentration, plasma lactate, glucose and free fatty acids after 8 weeks or brachial artery cross-section and vascular endothelial growth factor after 4 weeks of exercise and cryotherapy did not experience any significant changes between the cryotherapy and control group. Other physical, motor performance and physiological variables did not show a certain trend with regards to the way they were affected by cryotherapy. In some cases variables were affected significantly negatively while the opposite was true in other cases where variables were significantly positively influenced. With regard to the results of the study on the acute recovery of University netball players' lower leg muscles due to cryotherapy, it was found that the acute recovery of only four isokinetic variables were significantly influenced (p = 0.05) by cryotherapy, namely: left leg relative total dorsiflexion work, average peak dorsiflexion torque, right dorsiflexion and plantar flexion endurance. The acute recovery of the first mentioned strength endurance related variable was significantly negatively influenced by the cryotherapy. In contrast with this result the acute recovery of the three last mentioned isokinetic muscle relative peak torque and endurance related variables were significantly positively influenced by the cryotherapy. The overall conclusion that can therefore be drawn from the above-mentioned results show that the majority of isokinetic plantar- and dorsiflexion torque variables (12 out of 16, 75%) as well as other physical, motor performance and physiological variables experience no significant effect with regards to acute and long term recovery due to cryotherapy. The research did, however, show that the effectiveness of cryotherapy was influenced by the adiposity thickness, nature of the cryotherapy application, type of medium that was used for cryotherapy application and the length of time during which cryotherapy was applied. The recommendation for the use of cryotherapy as a recovery facilitating technique can be summarised as follows: the temperature of the cryotherapy medium that is used, must vary between 5°C and 10°C; the duration of cryotherapy between 15 and 20 minutes; the most general application area: for ice water immersion - immersed up until the level of the gluteal fold or crista ileac and the whole arm or forearm; for ice pack application - on the thigh, ankle and peripheral of the shoulder; the most common and effective ice pack application is direct on the skin surface by means of a bag filled with between 500 g and 1 500 g cubic formed ice. For long term use more that 2 consecutive days of cryotherapy application is recommended. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2008.

The objectives of this study were to determine the microbial ecology of “blown-pack” fresh beef obtained from a federally inspected facility and to use biopreservation to prevent spoilage of vacuum packaged chilled beef. Organic acids and alcohols in the purge obtained from the “blown” beef packages were detected using HPLC. PCR analysis indicated that Clostridium spp. were present in the purge of the commercial sample. Biochemical tests, RFLP and 16S rDNA sequencing were used to identify organisms isolated from the meat. Out of 66 isolated strains, 26 isolates were strict anaerobes and RFLP indicated that all were clonal isolates. Based on sequence analysis, the isolate was identified as Clostridium putrefaciens. The isolate caused “blown-pack” spoilage and produced butyric and propionic acids when inoculated onto fresh meat and Carnobacterium maltaromaticum UAL307 prevented the production gas and obvious signs of spoilage. / Food Science and Technology

Thesis (M.S.)--University of Montana, 2007. / Title from title screen. Description based on contents viewed Aug. 17, 2007. Includes bibliographical references (p. 113-120).

[pt] Um dos maiores problemas na indústria do petróleo durante a extração de hidrocarbonetos é a produção de sólidos, grãos de areia que usualmente são gerados a partir de formações pouco consolidadas, como nos arenitos, podendo causar erosão nas linhas de produção, equipamentos de elevação e de superfície, colapso de revestimentos e obstrução do poço. Esses eventos e outros relacionados representam para essa atividade, elevados custos ambientais e econômicos. Nesta dissertação foi simulado experimentalmente o funcionamento de sistemas de contenção de sólidos mais utilizados para poços horizontais sem revestimento, estes ensaios foram executados em blocos de arenitos sintéticos de grandes dimensões, através de uma célula cúbica que permitiu a aplicação de cargas de forma independente em três dimensões, sendo submetidos os corpos de prova a um estado plano de deformações, priorizando-se n os seguintes objetivos: primeiro analisar o comportamento mecânico de sistemas de contenção de areia em três casos, e segundo observar os efeitos físicos produzidos no gravel pack, quando submetido a um estado anisotrópico de tensões em uma formação com potencial de produção de sólidos. Os resultados foram satisfatórios mostrando em cada caso comportamentos similares, verificando-se que a tela centralizada com o gravel pack oferece melhores condições de suporte para a formação e para estabilidade do poço. / [en] A major problem in the oil industry during the extraction of hydrocarbons is the production of solid sand grains that are usually generated from some consolidated formations, as in sandstones, may cause erosion on production lines, lifting equipment and surface coatings collapse and obstruction of the well. These and other related events account for this activity, high environmental and economic costs. In this dissertation was simulated experimentally the operation of solid containment systems used to more horizontal wells without coating, these tests were run on synthetic sandstone blocks of large dimensions, through a cubic cell which allowed the application of loads independently in three dimensions, and subjected the specimens to a state plan deformations, focusing on the following objectives: first to analyze the mechanical behavior of systems containing sand in three cases, and second to observe the physical effects produced in the gravel pack, when subjected to an anisotropic state of stresses in a formation with a production potential of solids. The results were satisfactory in each case showing similar behavior, verifying that the central screen with gravel pack offers better support for the formation and stability of the well.