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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Pore development in meat products during deep-fat frying

Kassama, Lamin Samboujang January 2003 (has links)
The relationships between moisture loss and oil uptake and their effects on porosity, pore size distribution and pore structure during deep-fat frying of chicken breast meat were investigated. Chicken meat samples were deep-fat fried in an industrial fryer. The frying oil temperatures were 170, 180 and 190°C and samples were fried for times ranging from 5 to 900 s.
172

A case study analysis of sleep disturbance in the Parkinson's disease patient with deep brain stimulation

Wells, Tamara 08 September 2011 (has links)
Parkinson’s disease (PD) is a neurodegenerative movement disorder and a leading cause of neurological disability in the older adult population. Historically, the research and treatment of PD has focused on the associated motor symptoms. Now the non-motor symptoms such as sleep disturbance are becoming an increased focus for researchers. Deep brain stimulation (DBS) is a surgical intervention that has proven to be beneficial for PD motor symptom management. There are claims from the literature that DBS may assist with the phenomenon of sleep disturbance. A case study analysis was done to explore this concept in the DBS-PD patient population using the framework of the Symptom Management Theory. From the analysis of the subjective and objective data gathered it is clear that the phenomenon of sleep disturbance in this population is multifaceted and that DBS may play a role in managing the phenomenon of sleep disturbance for this population.
173

Population structure of demersal fish species in the north eastern Atlantic

O'Sullivan, Martha January 2009 (has links)
Neutral microsatellite markers were used to analyse genetic variation in three demersal finfish species, whiting (<i>Merlangius merlangus</i>) haddock (<i>Melanogrammus aeglefinus</i>) and anglerfish (<i>Lophius piscatorius</i>) in the north east Atlantic.  For each species samples were collected from the North Sea and west of the British Isles while geographically distant samples were also collected from Icelandic waters.  In the case of the anglerfish study samples were also taken from the Bay of Biscay and the Mediterranean Sea. Whiting appears to show the highest level of structuring in the north east Atlantic with samples from Icelandic waters being significantly divergent from samples on the continental shelf.  Just one of the continental shelf haddock samples, the Irish Sea, showed evidence of divergence from the Icelandic samples.  This general lack of divergence between Icelandic and continental shelf haddock is most likely reflective of a combination of relatively recent isolation and large effective population sizes (N<sub>e</sub>).  Apart from a few significant results (P&lt;0.05) continental shelf haddock and whiting conspecific populations tended to show little divergence.  This would also appear to be due primarily to large effective population sizes and a relatively recent isolation.  <i>L. piscatorius </i>showed a total absence of genetic differentiation between all the Atlantic samples which is consistent with the long distance movements associated with this species.  There was however strong evidence of divergence between the Atlantic and Mediterranean anglerfish samples. Comparing the results of the molecular studies presented here with non molecular approaches to determining population structure highlights the importance of combining information from several approaches if a sustainable management plan is to be put in place for commercial species.
174

Warm Forming Behaviour of ZEK100 and AZ31B Magnesium Alloy Sheet

Boba, Mariusz January 2014 (has links)
The current research addresses the formability of two magnesium sheet alloys, a conventional AZ31B and a rare earth alloyed ZEK100. Both alloys had a nominal thickness of 1.6 mm. Both Limiting Dome Height (LDH) and Cylindrical Cup Draw experiments were performed between room temperature and 350°C. To examine the effect of sheet directionality and anisotropy, LDH experiments were performed in both the sheet rolling and transverse directions. In addition, strain measurements were performed along both sheet orientations of the cylindrical cup and LDH specimens for which the geometry is symmetric. The LDH tests were used to study the formability of ZEK100 and AZ31B (O and H24 tempers) magnesium alloy sheet between room temperature and 350°C. At room temperature, AZ31B-O and AZ31B-H24 exhibit limited formability, with dome heights of only 11-12 mm prior to the onset of necking. In contrast, the dome heights of ZEK100 at room temperature reached 29 mm (a 140% improvement over AZ31B). Increasing the temperature above 200°C did not affect the relative ranking of the three sheet samples, however it did reduce the magnitude of the difference in dome heights. The rare earth alloyed ZEK100 had pronounced benefits at intermediate temperatures, achieving an LDH of 37 mm at 150°C; this dome height was only reached by AZ31B at a much higher temperature of 250°C. To further characterize the formability of ZEK100, forming limit curves (FLCs) were developed from the LDH tests in both the rolling and transverse directions. Comparisons to AZ31B were made at selected temperatures. Surface strain data was collected with an in situ digital image correlation (DIC) system incorporating two cameras for stereo observation. Results from these experiments further highlighted the enhanced formability relative to AZ31B over the entire temperature range between room temperature and 350°C, with the most dramatic improvements between room temperature and 150°C. The plane strain forming limit (FLC0) for ZEK100 at 150°C was 0.4 which equals that of AZ31B at 250°C. At higher temperatures (300°C), the two alloys exhibited similar performance with both achieving similar dome heights at necking of 37 mm (AZ31B) and 41 mm (ZEK100). To round out the investigation of ZEK100 for industrial applications, cylindrical cup deep drawing experiments were performed on ZEK100 sheet between 25°C and 250°C under isothermal and non-isothermal conditions. Draw ratios of 1.75, 2.00 and 2.25 were considered to examine the effects of draw ratio on draw depth. The effect of sheet anisotropy during deep drawing was investigated by measuring the earring profiles, sheet thickness and strain distribution along both the rolling and transverse directions. Isothermal test results showed enhanced warm temperature drawing performance of ZEK100 over AZ31B sheet; for example, a full draw of 203.2 mm (8”) blanks of ZEK100 was achieved with a tool temperature of 150°C, whereas a tool temperature of 225°C was needed to fully draw AZ31B-O blanks of this diameter. Non-isothermal deep draw experiments showed further improvement in drawability with significantly lower tooling temperatures required for a full cup draw using ZEK100. ZEK100 achieved a full draw of 228.6 mm (9") blanks with a die and blank holder temperature of 150°C and a cooled punch (25°C) while the same size blank of AZ31B required a die and blank holder temperature 225°C and a cooled punch (150°C). Temperature process windows were developed from the isothermal and non-isothermal results to show a direct comparison of drawing behaviour between ZEK100 and AZ31B. Overall, ZEK100 offers significantly improved forming performance compared to AZ31B, particularly at temperatures below 200°C. This lower temperature enhanced formability is attractive since it is less demanding in terms of lubricant requirements and reduces the need for higher temperature tooling.
175

A case study analysis of sleep disturbance in the Parkinson's disease patient with deep brain stimulation

Wells, Tamara 08 September 2011 (has links)
Parkinson’s disease (PD) is a neurodegenerative movement disorder and a leading cause of neurological disability in the older adult population. Historically, the research and treatment of PD has focused on the associated motor symptoms. Now the non-motor symptoms such as sleep disturbance are becoming an increased focus for researchers. Deep brain stimulation (DBS) is a surgical intervention that has proven to be beneficial for PD motor symptom management. There are claims from the literature that DBS may assist with the phenomenon of sleep disturbance. A case study analysis was done to explore this concept in the DBS-PD patient population using the framework of the Symptom Management Theory. From the analysis of the subjective and objective data gathered it is clear that the phenomenon of sleep disturbance in this population is multifaceted and that DBS may play a role in managing the phenomenon of sleep disturbance for this population.
176

Methodological approaches to the optimization of observatory systems for the study of benthic ecological processes

Robert, Katleen 15 August 2011 (has links)
Although the deep seafloor represents the largest biome on the planet, its benthos has remained understudied because of logistical difficulties and the cost of access. Long-term, time-series information is needed to understand the small-scale and inter-annual variations required to build predictive models of ecological processes. In this thesis, we employed three newly developed observatory systems, which coupled in situ imagery with environmental data to examine ecological processes in three deep-sea benthic habitats: 1) Megabenthic surface bioturbation on the upper continental slope (400m depth) near Barkley Canyon, off Vancouver Island, 2) Thermal response in polynoid taxa at Main Endeavour Hydrothermal Vent Field (2,100m depth) on the Juan de Fuca Ridge and 3) Behavioural rhythms and bacterial mat growth in Saanich Inlet (100m), a fjord in southern Vancouver Island. To ensure that the imagery collected was useful for quantitative hypothesis testing by a single observer, we employed a step-wise methodological approach, taking advantage of previously acquired knowledge and, in two cases, the interactive nature of cabled observatories, to tailor the sampling frequency to the variables of interest. The application of a diverse array of image analysis techniques and statistical models, easily extendable to other systems, was also demonstrated. The results obtained while conducting the protocol optimization phase described organism and community level responses to environmental variations. Using a remotely operated camera connected to the NEPTUNE Canada cabled observatory, we estimated that total surface sediment turnover by sea urchins and flatfish, the two most important megafaunal contributors, within the field of view required 93 to 125 days in the absence of phytodetrital accumulations. When employing a camera-temperature array system, the most frequently observed mobile megafaunal species, two polynoid taxa, were not found to exploit the recorded temperature gradients suggesting that they employed a thermoconforming strategy to cope with thermal variability. In the aphotic, mostly hypoxic benthos of Saanich Inlet, strong behavioural entrainment, neither diel nor tidal, was not observed. However, significant changes in species composition and bacterial mat substratum coverage were observed following intrusion of oxygenated waters, a yearly event resulting from specific bathymetric features and oceanographic dynamics of this fjord. A Bayesian approach to data modeling was found to be particularly well suited to protocol optimization purposes as complex models could be more easily and intuitively implemented. The further application of our multi-disciplinary step-wise approach will reduce the time required to approach new ecological questions and improve integration of studies carried in different locations. By carefully choosing ecosystem functions which can be used as indicators of change, the current baseline state of the system can be described. Informed long-term monitoring initiatives can then be implemented in order to quantify global ocean responses to anthropogenic factors such as climate change, resource extraction or eutrophication. / Graduate
177

Small x physics

Askew, Adrian John January 1995 (has links)
We study the small-z limit of the structure functions for deep inelastic scattering in Quantum Chromodynamics. The standard approach to this process, based on the DGLAP equations, runs into difficulties in the small-x region due to the higher order corrections becoming large. As an attempt to overcome these obstacles we reinterpret the small-z limit in terms of high energy asymptotics. The relevant high energy formalism is developed in terms of Reggeon Field Theory, which leads to the BFKL equation for the scattering amplitude. These results are reviewed fully, for completeness. We then apply the resulting formalism to structure functions at small-z to determine the phenomenological implications of this high energy resummation. The DESY electron-proton collider HERA is presently exploring the region of the structure functions for x ≤ 10(^-3), Q(^2) ~ 10 GeV(^2) and the results of these experiments are compared with our theoretical analysis. The structure functions are a very inclusive measurement; so in order to try and focus on some cleaner indication of the BFKL behaviour we then turn to an analysis of dijet production in deep inelastic scattering. The results of the BFKL formalism are compared with standard analysis in terms of the DGLAP equations.
178

Quality changes in chicken nuggets fried in oils with different degrees of hydrogenation

Li, Yunsheng, 1972- January 2005 (has links)
The goal of this research was to investigate the influence of the degree of hydrogenation of frying oil on quality and textural changes in chicken nuggets during deep-fat frying. Thermal stabilities of the frying oils were also studied. The frying oil consisted of blends of hydrogenated and non-hydrogenated oils mixed at different ratios. Physical and textural attributes of the products, as well as the moisture and fat contents, were measured at various frying times. Oil samples were withdrawn at different times and analyzed for colour, free fat acid (FFA) content, viscosity and dielectric properties. Physical and textural properties of chicken nuggets were influenced by frying time and the degree of oil hydrogenation. The experimental data, for changes in the properties of both flying oil and fried product, was adequately described using first order reaction kinetics. Increasing frying time decreased product lightness whereas chroma and hardness values increased. Frying in oils with higher degrees of hydrogenation resulted in products with lighter and harder (more crispy) texture. Products fried in non-hydrogenated oil absorbed more oil but also retained more moisture compared to samples fried in hydrogenated oil. The rate of change in the colour parameters of oils was observed to increase with increasing frying time and the degree of hydrogenation. The chroma values of the oils increased when frying time increased and degree of hydrogenation decreased. The viscosity of oil tended to increase with increasing degree of hydrogenation. The FFA content and dielectric constant of the frying oils correlated with frying time and degree of hydrogenation.
179

A feasibility study of exploration for deep seated ore bodies in the Skellefte field

Malmqvist, Kerstin January 1979 (has links)
Simulation technique has been used for a feasibility study of a deep exploration project for massive sulphides in an old mining district, the Skellefte field. The outcome under very different conditions has been studied. Under the specific conditions of the well known Skellefte field it is found to be possible to even calibrate the mathematical model.It is found that when the geology is not known in detail, an outcome of the order of 50 tons per meter drillhole is to be expected under a simple drilling strategy.When a certain knowledge about the general structures down to around 1 000 m is established, it is possible to improve the outcome by a factor of 2 through an optimization of the depth of investigation. The optimal depth of investigation is in the order of 500 m.On the other hand, when a minimum ore value is introduced as a function of depth, the expected outcome will again decrease with a factor of about 3.It must be underlined, that these results are average values in a mathematical model and do not say anything about the outcome in the single exploration case. However, in exploration campaigns of the order of 40 drillholes to a depth of 1000 m an analysis shows that at least one deep seated large body was found in 25% ot the exploration campaigns.Faced with the problem whether to go or not to go into a deep exploration phase, this technique can headlight the problem and it can give an estimate about the order of costs and benefits. / digitalisering@umu
180

Deep inelastic scattering and bag model /

Signal, Anthony Ian. January 1988 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, 1988. / Typescript. Copies of three papers (2 published), co-authored by the author, in back. Includes bibliographical references (leaves 179-186).

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