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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.
151

Presente e futuro da análise de dados de fatores associados à soroprevalência da diarreia viral bovina / Present and future of data analysis of associated factors to seroprevalence of bovine viral diarrhea

Machado, Gustavo January 2016 (has links)
O vírus da diarreia viral bovina (BVDV) causa uma das doenças mais importantes de bovinos em termos de custos econômicos e sociais, uma vez que é largamente disseminado na população de gado leiteiro. Os objetivos do trabalho foram estimar a prevalência em nível de rebanho e investigar fatores associados aos níveis de anticorpos em leite de tanque através de um estudo transversal, bem como discutir e comparar diferentes técnicas de modelagem, as tradicionais como regressão e as menos usuais para este fim, como as de Machine learning (ML) como Random Forest. O estudo transversal foi realizado no estado do Rio Grande do Sul para a estimação da prevalência de doenças reprodutivas baseados em amostras de tanque de leite, partindo de uma população total de 81.307 rebanhos. Foram coletadas 388 amostras de tanque de leite, e nas propriedades selecionadas foi aplicado um questionário epidemiológico. Como resultados se identificou uma prevalência de 23,9% (IC95% = 19,8 - 28,1) de propriedades positivas. Através de análise de regressão de Poisson se identificou como fatores associados o BVDV: o exame retal como rotina para o diagnóstico de prenhes, Razão de Prevalência [PR] = 2,73 (IC 95%: 1.87-3.98), contato direto entre animais (contato via cerca de propriedades lindeiras) (PR=1,63, IC 95%: 1.13-2.95) e propriedades que não utilizavam inseminação artificial (PR=2.07, IC 95%: 1.38-3.09) Na técnica de Random Forest pôde-se identificar uma dependência na ocorrência de BVDV devido a: inseminação artificial quando realizada pelo proprietário da propriedade ou capataz, o número de vizinhos que também possuem criação de bovinos, e em concordância com os resultados da regressão quanto a dependência da ocorrência de BVDV devido a palpação retal. Como resultado, pôde-se perceber que o BVDV está distribuído no estado do RS e caso seja de interesse do poder público, o desenvolvimento de um programa de controle da doença pode ser baseado nos resultados encontrados. Por outro lado, a contribuição deste estudo vai além das tradicionais análises realizadas em epidemiologia veterinária, principalmente devido os bons resultados obtidos com a abordagem por ML neste estudo transversal. Por fim, a utilização de técnicas estatísticas mais avançadas contribuiu para elucidar melhor os fatores possivelmente envolvidos com a ocorrência de BVDV no rebanho leiteiro gaúcho. / The bovine viral diarrhea virus (BVDV) causes one of the most important disease of cattle in terms of economic and social costs, since it is widely disseminated in dairy cattle population. The objectives were to estimate the herd level prevalence at and investigate factors associated with antibody levels in bulk tank milk through a cross sectional study, discuss and compare different modeling techniques such as the traditional regression with the ones less used for this approach machine learning (ML). The cross sectional study was conducted in Rio Grande do Sul state to estimate the prevalence of reproductive diseases based on bulk tank milk samples, from a total population of 81,307 herds. Milk samples from 388 bulk tank were sampled, and an epidemiological questionnaire was applied in each farm. The prevalence was 23.9% (95% CI 19.8 - 28.1). Through the Poisson regression analysis, the following factors associated with BVDV were found: routine use of rectal examination for pregnancy (Prevalence Ratio [PR] = 2.73 (IC 95%: 1.87-3.98), direct contact between/among animals (contact over the fence of neighboring farms) (PR = 1.63, IC 95%: 1.13-2.95) and properties that did not use artificial insemination (PR = 2.07, IC 95%: 1.38-3.09). On the other hand, using ML techniques, it was identify a dependency upon the occurrence of BVDV due to: artificial insemination when carried out by the owner of the property or foreman; the number of neighbors who also have cattle, and in accordance with the regression results as the dependence of the occurrence of BVDV due to routine use of rectal examination for pregnancy. BVDV is spread across the State and if the government's interest to launch a disease control program measures should be focusing mainly on better conditions and care in reproduction. On the other hand, the contribution of this study goes beyond traditional analyzes in veterinary epidemiology, mainly due to the good results obtained with the approach by ML in this cross-sectional study. Finally, the use of advances statistics techniques it has been made progress to better elucidate the factors possibly involved in the occurrence of BVDV in state dairy herds.
152

“Not Quite Mechanical:” Tanks and Men on the Western Front

January 2018 (has links)
abstract: In 1916, in the middle of the First World War, Britain developed and deployed the first military tanks on a battlefield, signifying a huge step forward in the combination of mechanization and the military. Tanks represented progress in technical and mechanical terms, but their introduction to military goals and military environments required the men involved to develop immaterial meanings for the tanks. Tactically, tanks required investment from tank commanders and non-tank commanders alike, and incorporating tanks into the everyday routine of the battlefront required men to accommodate these machines into their experiences and perspectives. Reporting the actions of the tanks impelled newspapers and reporters to find ways of presenting the tanks to a civilian audience, tying them to British perspectives on war and granting them positive associations. This thesis sought to identify major concepts and ideas as applied to the British tanks deployed on the Western Front in the First World War, and to better understand how British audiences, both military and civilian, understood and adopted the tank into their understanding of the war. Different audiences had different expectations of the tank, shaped by the environment in which they understood it, and the reaction of those audiences laid the foundation for further development of the tank. / Dissertation/Thesis / Masters Thesis History 2018
153

Effects of headwinds on towing tank resistance and PMM tests for ONR Tumblehome

Cook, Shane Stuart 01 December 2011 (has links)
Calm water towing tank experiments consisting of resistance tests and static and dynamic planar motion mechanism (PMM) tests are performed for a surface combatant with primary focus on the effects of hurricane scale headwinds. The experiments are designed to gain a better understanding of the physics of ship response to wind and to provide a validation dataset for an unsteady Reynolds-averaged Navier Stokes (RANS)-based computational fluid dynamics (CFD) code used for computing both air and water flow around a ship. Hurricane scale wind speeds are chosen to maximize the measurable effect of wind on ship forces and motions for a more definitive analysis and comparison with CFD. The geometry is the 1/48.9 scale fully appended ONR Tumblehome model 5613, which has length L = 3.147 m and is equipped with a superstructure. Tests are performed in a 3.048 × 3.048 × 100 m towing tank with wind generated by a custom built wind carriage towed ahead of the ship model. Air-stream velocity measurements indicate a maximum relative wind speed magnitude of 9.38 m/s with 6 - 7% uniformity and RMS values of approximately 4.5%. The effects of three wind speeds on static and dynamic forces, moment, and motions are analyzed. Results show that wind contributes significantly to surge force (approximately 46% at Fr = 0.2). Resistance data shows agreement with CFD computations with errors averaging approximately 4%. The drag coefficient above water is approximately 0.3 and generally decreases with increasing ship speed. Sway force and yaw moment are largely affected when the ship experiences oblique orientation to the flow. Forces and moment exhibit quadratic scaling with wind speed. Roll is the most sensitive motion to wind and is counteracted by it up to 1.8° for PMM test conditions. In addition, harmonic amplitudes of forces and moment data from dynamic tests are used to determine hydrodynamic derivatives for all three wind conditions following a mathematical model. The effect of wind on hydrodynamic derivatives is significant with changes on the order of 10 - 100%.
154

Simulation of fluid-structure interaction for surface ships with linear/nonlinear deformations

Paik, Kwang Jun 01 May 2010 (has links)
The present research develops a numerical fluid-structure interaction (FSI) code based on CFDShip-Iowa version 4, a general-purpose URANS/DES overset fluid solver. Linear and nonlinear FSI methods are developed to compute structural responses on surface ships or marine structures. The modal superposition transient analysis and the nonlinear FEM structure solver are used for small and large deformation FSI problems, respectively. The gluing method is applied to transfer the forces and displacements on non-matching grids for fluid and structure domains. The linear FEM solver is applied to deform the boundary layer grid with large deformation in the fluid domain, while the deformation is ignored in small deformation problems. Deformation of an interior point in the boundary layer grid is obtained using linear interpolation in both linear and nonlinear deformation problems. The S175 containership is studied in regular waves as an application example for the linear problem. Heave and pitch responses are compared with the experiments, showing good agreement. Time histories of vertical bending moment (VBM) are calculated using rigid model, one-way coupling, and two-way coupling approaches. The elastic models are able to capture the ringing of the VBM induced by slamming, while the rigid model shows a peak at the moment of slamming without further fluctuations. The two-way coupling method shows the effects of hull deformation on the amplitude and phase of VBM as well as the accelerations of heave and pitch. For the nonlinear deformation problem three sloshing tanks with an elastic bar clamped to its bottom or top are simulated and compared with the experiments and other numerical simulation results. The present simulation results show reasonable agreement with the experiments for bar deformation and free surface elevation. A secondary wave on the free surface is creadted by the vorticity generated from the free surface. The effect of the bar on the sloshing impact is studied comparing dynamic pressure acting on the tank wall without bar, with an elatic bar, and with a rigid bar.
155

Propriedades Físico-Químicas e Primórdios Da Perda de Estabilidade de Calda Inseticida em Misturas com Fungicidas e Adjuvantes /

January 2019 (has links)
Resumo: Devido a frequente demanda por aplicações de produtos fitossanitários dada pela ocorrência simultânea de pragas (insetos, doenças e planta-daninha) em uma mesma área e a procura do agricultor em otimizar recursos financeiros e operacionais na lavoura, a prática de misturas em tanque de diferentes classes de produtos fitossanitários tem sido cotidiana. Os efeitos resultantes das misturas, relativos a fatores como às formulações, às dosagens e a interação entre os produtos a serem aplicados, estão associados a compatibilidade entre as formulações e às alterações físico-química nas caldas, que podem resultar na perda de eficácia dos produtos aplicados e ainda em efeitos tóxicos para a cultura tratada e ao ambiente. Nesse cenário, o objetivo desse trabalho foi avaliar as propriedades físico-químicas de calda inseticida e identificar primórdios de perda da estabilidade de misturas com fungicidas e adjuvantes. Os tratamentos foram constituídos da combinação do inseticida tiametoxam + lambda-cialotrina com os fungicidas fluxapiroxade + piraclostrobina e clorotalonil e adjuvantes lecitina e ácido propiônico e óleo mineral. Foram realizadas avaliações de características físico-químicas das combinações, quanto ao pH, condutividade elétrica, tensão superficial e ângulo de contato resultantes das caldas preparadas. Para a avaliação dos primórdios de perda da estabilidade estoudou-se o comportamento reológico, a viscosidade, o potencial zeta, a distribuição de tamanho de partículas disper... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Due to frequent demand for pesticide applications, imports of financial and operational resources in tillage, a practice of tank storage of different classes phytosanitary products has been daily. The effects of the mixtures are factors such as the formulations, the dosages and the interactions between the products that are applied, are associated to the compatibility between the formulations and the physical of the chemical complex in the syrups, that can cause the breakage of its products and also in toxic effects on the treated crop and the environment. In this scenario, the use of chemical-chemical syrups proved to be insidious and identitarian, impairing the stability of the mixtures with fungicides and adjuvants. The isolates were constituted by the combination of the insecticide thiamethoxam + lambda-cyhalothrin with fungicides fluxapiroxade + pyraclostrobin and chlorothalonil and lecithin and propionic and mineral acid adjuvants. The physical, chemical and enzymatic properties, such as pH, electrical conductivity, surface tension and the contact bottom of the prepared syrups were discontinued. For an evaluation of the stability results, viscosity, zeta potential, dispersion capacity and physical stability of the grouts. The combination of the thiamethoxam + lambda-cyhalothrin insecticide with the chlorothalonil fungicide and the lecithin and propionic acid adjuvants and the mineral oil interfere with the coating of the target, eliminating the surface tension of the sy... (Complete abstract click electronic access below) / Mestre
156

Water and Health in the Nandamojo Watershed of Costa Rica: Community Perceptions towards Water, Sanitation, and the Environment

Mcknight, James 13 June 2014 (has links)
Understanding the relationships between human health, water, sanitation, and environmental health is a requirement to understanding the challenges that face researchers when it comes to addressing global health relating to water and sanitation. Access to improved water and sanitation is not only a precondition to health, but to all aspects of daily living. Target 7.C of the Millennium Development Goals (MDGs) addresses worldwide disparities in access to improved water and sanitation by calling for the reduction in "half of the proportion of people without sustainable access to safe drinking water and sanitation by 2015". Over 90% of the population of Costa Rica has access to improved water and sanitation, thus exceeding the water and sanitation targets for the Millennium Development Goals (MDGs). Despite having access to water and sanitation, little is known whether communities are only interested in access or if quality and quantity of water and sanitation systems are as equally as important. Target 7.c of the MDGs does not include water quality in the definition of safe water. Furthermore, the use of the words "safe" and "improved" in the target are often interchanged and can be misleading, especially when considering the impact of water quality on population health. In Costa Rica, households in the Nandamojo watershed have access to improved water and sanitation; it is unclear whether the drinking water is potable with respect to Costa Rican and the World Health Organization (WHO) water quality standards. The impact of leaking septic systems on human and environmental health is also unknown. Illnesses associated with recreational water are an increasing public health problem, causing a great burden of disease in bathers every year. The global health impact of infectious diseases associated with recreational water exposure has been estimated at around three million disability-adjusted life years (DALYs) per year, resulting in an estimated economic loss of around twelve billion dollars per year. Fecal and chemical contamination of recreational water is a concern, especially in areas of non-point source pollution. Health-based water monitoring is often conducted in recreational waters as a tool for assessing risk. In Costa Rica, recreational water sampling is conducted at coastal beach areas only, neglecting other surface waters used by residents and tourists. Community perspectives regarding recreational water use and the associated risks are limited. Understanding these perspectives will enable public health professionals to better target community needs, such as education and to address the concerns of participating communities. This dissertation was divided into three chapters. The first chapter explored community perceptions on improved water and sanitation, the second chapter assessed community water systems and the risk of acute diarrheal disease, and the third chapter captured community perceptions on recreational water use and the risk of waterborne illness. Methodologies for water sampling and analyses were used to assess water quality, while household interviews and focus groups were conducted to capture qualitative data. Results from the first chapter showed participants had positive perceptions towards their improved water and sanitation systems. Household interviews revealed almost half of the respondents had concerns with water quality, while less than 25% did not think their septic tanks leaked or overflowed during rain events. Focus group discussions revealed common themes. Participants identified water quality, health, pipes, water scarcity, odors, insects, and overflow/infiltration of water and sanitation to be important issues. Participants revealed convenience, improved health and safety and the lack of odors to be themes directly related to customer satisfaction of improved water and sanitation. Results from the second study revealed 57% of household samples had total coliform bacteria above the Costa Rican standard for safe drinking water exceeding the single standard limit of zero, while 61% failed the World Health Organization standard for fecal coliforms exceeding the single standard limit of zero. AGII was identified in 41 of the 378 household residents (11%). The odds ratio for AGII among household residents with a water sample positive for total coliforms was 1.88 (0.81-3.17). Fecal coliforms were statistically significant for those with AGII (OR = 3.19, 1.43-7.12). Regression modeling analyses revealed individuals with AGII and household drinking water positive for fecal coliforms to be statistically significant (OR = 3.01, 1.33 - 6.84), while other covariates (total coliforms, gender, treated water, and families) also had odds ratios greater than one, but were not significant. Results from the third chapter indicated most respondents felt recreational water sources, such as streams and rivers were contaminated with human, animal, and chemical wastes. Focus group participants also stated they did not use inland waters for recreational purposes for these reasons. However, many did admit using marine water for recreational bathing and felt these areas were not contaminated. These beliefs did coincide with the water quality results from freshwater sources, but not marine sources. Fecal coliform contamination was widespread throughout the watershed in freshwater sources. Marine water samples failed the World Health Organization (WHO) and Costa Rican recreational water standards for fecal coliform and enterococci in 36% and 6% of the samples, respectively. The overall results of this dissertation suggest that the definitions of improved water and sanitation have to include, at a minimum, water quality, water quantity, proper construction and containment of storage tanks, and oversight and maintenance of these systems. Given the challenges facing communities in the Nandamojo watershed regarding water and sanitation, it is essential for scientists, researchers, policy makers, water committees, health providers, and community members to design and implement strategies in water resource management and proper waste management. Communities and water committees would also be best served if they worked with government agencies to conduct concurrent testing of both recreational water and drinking water, especially since both them target many of the same parameters.
157

The effects of weld-induced imperfections on the stability of axially loaded steel silos

Pircher, Martin, University of Western Sydney, College of Science, Technology and Environment, School of Civic Engineering and Environment January 2000 (has links)
The strength of thin-walled cylindrical shell structures is highly dependent on the nature and magnitude of imperfections. Most importantly, circumferential imperfections have been reported to have an especially detrimental effect on the buckling resistance of these shells under axial load. Due to the manufacturing techniques commonly used during the erection of steel silos and tanks, specific types of imperfections are introduced into these structures, among them circumferential weld-induced imperfections between strakes of steel plates. The main objective of this thesis was to investigate the exact nature of these circumferential welds and their influence on the buckling resistance of silos and tanks under axial load. The results of a survey of imperfections in existing silos at a location in Port Kembla / Australia (Ding 1992) were used to develop and calibrate a shape function which accurately describes the geometric features of circumferential weld imperfections. It was found that after filtering out the effects of overall imperfections, three parameters governed the shape of the surveyed imperfections: the depth; the wave length; and the roundness. A study on several factors influencing the buckling of silos and tanks was carried out using the finite element method. The interaction between neighbouring circumferential weld imperfections was investigated and it was found that the influence on the buckling behaviour depended on the strake height in relation to the linear meridional bending half wave length and the depth of the imperfection. The strengthening effect of weld-induced residual stress fields for a range of different geometries was also studied, and diagrams were derived giving the influence of the newly developed shape function on the buckling behaviour. A post-buckling analysis was undertaken and a model for the post-buckling behaviour of cylindrical thin-walled shells with circumferential weld imperfections was developed. The methods used for the analysis of thin-walled cylinders were applied in a study on the buckling behaviour of welded box-sections. It was found that weld-induced residual stress fields governed the buckling behaviour of these columns / Doctor of Philosophy (PhD)
158

Radiotherapy X-ray dose distribution beneath retracted patient compensators

Piyaratna, Nelson, University of Western Sydney, Nepean, Faculty of Science and Technology January 1995 (has links)
Computer designed missing tissue and dose compensators have been produced and dosimetrically tested under a linear accelerator 6MV X-ray beam. Missing tissues compensators were developed to correct for patient external contour change only. Target dose compensators were developed to achieve a uniform dose throughout the target volume. With compensators present in the beam, data acquisition was repeated in a water phantom and an Anthropomorphic phantom. Clinically acceptable dose uniformity was achieved within these phantoms. For external contour compensation flat isodose curves were obtained giving an even dose in the region of interest. The dose difference found was within plus/minus 3% only. For the phantoms containing inhomogeneities dose uniformity to target volume was achieved within plus/minus 7%. Prediction of radiation dose was made using a GE Target Series 2 Treatment Planning Computer for each of the phantoms. Validation of the computer predicted dose was carried out using diode and TLD measurements. The measured data in the water tank was consistent with the computer data within plus/minus 2% for external contour changes and for inhomogeneities. The TLD measured results in the anthropomorphic phantom agreed with the planning computer results within 6%. Up to 4% of the difference is explainable due to supra-linearity and scatter effects / Master of Science (Hons) (Physics)
159

Inland Saline Aquaculture: Overcoming Biological and Technical Constraints Towards the Development of an Industry.

gavin.partridge@challengertafe.wa.edu.au, Gavin Partridge January 2008 (has links)
Secondary salinisation has rendered over 100 million hectares of land throughout the world, and over 5 million hectares in Australia, unsuitable for conventional agriculture. The utilization of salinised land and its associated water resources for mariculture is an adaptive approach to this environmental problem with many potential economic, social and environmental benefits. Despite this, inland mariculture is yet to develop into an industrial-scale, rural enterprise. The main aim of this study was therefore to identify and address some of the technical and biological limitations to the development of an inland finfish mariculture industry. Three technical aspects essential to the development of an Australian inland mariculture industry were reviewed; potential sources of water, the species suitable for culture in these water sources and the production systems available to produce them. Based on factors such as their quantity, quality and proximity to infrastructure, the most appropriate water sources were deemed to be groundwater obtained from interception schemes and waters from operational or disused mines. In terms of species, mulloway (Argyrosomus japonicus) were identified as having many positive attributes for inland mariculture, including being temperate and therefore having the ability to be cultured year-round in the regions where the majority of secondary salinity occurs. Seasonal production of barramundi (Lates calcarifer) in ponds in the temperate climatic zones has potential, but may be more appropriate for those salinised water sources located in the warmer parts of the country. Rainbow trout (Oncorhynchus mykiss) were also identified as having excellent potential provided water temperature can be maintained below the upper lethal limit and also have potential for seasonal production, perhaps in rotation with barramundi. In terms of production systems, pond-based culture methods were found to have many advantages specific to inland mariculture. Static ponds enable culture in areas with low groundwater yield and more cost-effective potassium supplementation compared with flow through ponds. Static ponds also largely overcome the issues associated with the disposal of salt-laden and eutrophied waste water; however yields from static ponds are typically low and limited by the nutrient input into the pond. In response to the yield constraints of static pond culture, a new culture technology known as the Semi-Intensive Floating Tank System (SIFTS) was designed, patented and constructed in collaboration with the aquaculture industry and tested in a static inland saline pond in the wheatbelt of Western Australia. This technology was designed to reduce nutrient input into ponds by the collection of settleable wastes and to provide large volumes of well-oxygenated water to the target species, to ameliorate the loss of fish from low dissolved oxygen during strong microalgal blooms. The three species identified above has having excellent potential for inland mariculture (mulloway, rainbow trout, and barramundi) were grown in SIFTS held within a 0.13 ha static, inland saline water body (salinity 14 ppt) over a period of 292 days, yielding the equivalent of 26 tonnes/ha/year (total for all three species). Rainbow trout were grown with an FCR of 0.97 from 83 to 697 grams over 111 days (SGR, 1.91%/day) between June and September, when average daily water temperatures ranged from 12.3„aC to 18.2„aC. Over the same time period, mulloway grew only from 100 to 116 grams, however, once temperatures increased to approximately 21„aC in October, feed intake increased and mulloway grew to an average size of 384 grams over 174 days with an SGR and FCR of 0.68 %/day and 1.39, respectively. Barramundi stocked in November with an average weight of 40 grams increased to 435 grams in 138 days (SGR 1.73%/day) with an FCR of 0.90. The SIFTS significantly reduced nutrient input into the pond by removing settleable wastes as a thick sludge with a dry matter content of 5 to 10%. The total quantity of dry waste removed over the 292 day culture period was 527 kg (5 tonnes/ha/yr), which was calculated to contain 15 kg of nitrogen (144 kg/ha/yr) and 16 kg of phosphorus (153 kg/ha/yr). The release of soluble nutrients into the pond resulted in blooms of macro- and micro- algae which caused large and potentially lethal diurnal fluctuations in dissolved oxygen within the pond, however, comparatively stable levels of dissolved oxygen were maintained within each SIFT through the use of air lift pumps. It is well documented that saline groundwater is deficient in potassium which, depending on the extent of the deficiency, can negatively impact on the performance of marine species, including fish. The physiological effects of this deficiency on fish, however, have not been previously described. As such, I conducted a bioassay investigating the physiological effects of a hypersaline (45 ppt) groundwater source containing 25% of the potassium found in equivalent salinity seawater (i.e. 25% K-equivalence) on juvenile barramundi. Histopathological examination of moribund fish revealed severe degeneration and necrosis of skeletal muscles, marked hyperplasia of branchial chloride cells and renal tubular necrosis. Clinical chemistry findings included hypernatraemia and hyperchloridaemia of the blood plasma and lowered muscle potassium levels. It was concluded from this study that the principal cause of death of these barramundi was skeletal myopathy induced by unsustainable buffering of blood plasma potassium levels from the muscle. Although such hypokalaemic muscle myopathies have been previously described in mammals and birds, this was the first description of such myopathies in fish. It was hypothesized from the results described above that the physiological effects of potassium deficiency are dependent on salinity and that they would be ameliorated by potassium supplementation. These predictions were tested in a subsequent study which measured the effects of potassium supplementation between 25% and 100% K-equivalence on the growth, survival and physiological response of juvenile barramundi at hyperosmotic (45 ppt), near-isosmotic (15 ppt) and hyposmotic (5 ppt) salinities. Unlike those juvenile barramundi reared at 45 ppt and 25% K-equivalence in the previous study, those reared in 50% K-equivalence water at 45 ppt in this study survived for four weeks but lost weight; whereas at 75% and 100% K-equivalences fish both survived and gained weight. Homeostasis of blood plasma potassium was maintained by buffering from skeletal muscle. Fish reared in 50% K-equivalence at this salinity exhibited muscle dehydration, increased branchial, renal and intestinal (Na+-K+)ATPase activity and elevated blood sodium and chloride, suggesting they were experiencing osmotic stress. At 15 ppt, equal rates of growth were obtained between all K-equivalence treatments. Buffering of plasma potassium by muscle also occurred but appeared to be in a state of equilibrium. Barramundi at 5 ppt displayed equal growth among treatments. At this salinity, buffering of plasma potassium from muscle did not occur and at 25% K-equivalence blood potassium was significantly lower than at all other K-equivalence treatments but with no apparent effect on growth, survival or (Na+-K+)ATPase activities. These data confirmed the hypothesis that proportionally more potassium is required at hyperosmotic salinities compared to iso- and hypo- osmotic salinities and also demonstrated that barramundi have a lower requirement for potassium than other marine and estuarine species being investigated for culture in inland saline groundwater. In addition to ongrowing fish, saline groundwater has potential for hatchery production. Specific advantages include the vertical integration of inland saline farms and the production of disease-free certified stock through isolation from the pathogens and parasites found naturally in coastal water. To determine the potential of utilizing inland saline groundwater for hatchery production, barramundi larvae were reared from 2 to 25 days post hatch in 14 ppt saline groundwater with either no potassium supplementation (38% K-equivalence) or full potassium supplementation (100% K-equivalence). Growth, survival and swimbladder inflation of these larvae were compared against those grown in control treatments of seawater (32 ppt) and seawater diluted to 14 ppt. Those reared in saline groundwater with 38% K-equivalence exhibited complete mortality within 2 days, whilst those held in groundwater with full supplementation survived at a rate equal to both control treatments (pooled average 51.1 ¡Ó 0.5%). At 25 days post hatch, there was no significant difference in larval length or dry weight between those grown in the 14 ppt control treatment and those in the saline groundwater with full potassium supplementation. There were no significant differences in swim bladder inflation between any of the surviving treatments (average 93.3 ¡Ó 2.5%). This is the first description of rearing barramundi larvae both in low salinity seawater and in saline groundwater, and demonstrates that the requirement for potassium by larval barramundi is higher than for juveniles of the same species. In addition to a deficiency in potassium, saline groundwater in Western Australia often contains an elevated concentration of manganese relative to seawater as a result of anaerobic reduction of manganese oxides or the pedogenic weathering of manganese-bearing rock. The effects of elevated manganese on marine or estuarine fish have not been described and a study was therefore conducted to determine if manganese, at a concentration typical of that found in saline groundwater, has any impact on fish. The effects of 5 mg/L of dissolved manganese on juvenile mulloway at salinities of 5, 15 and 45 ppt were determined by comparing the survival, growth and blood and organ chemistry with those grown at the same salinities without manganese addition. Survival of mulloway at 45 ppt in the presence of 5 mg/L of manganese (73 ¡Ó 13%) was significantly lower than all other treatments, which achieved 100% survival. Those fish grown in seawater without manganese exhibited rapid growth, which was not affected by salinity (SGR = 4.05 ¡Ó 0.29%/day). Those fish grown at 5 ppt and 45 ppt in the presence of manganese lost weight over the two week trial (SGR 0.17 ¡Ó 0.42 and -0.44 ¡Ó 0.83%/day, respectively), whilst those at 15 ppt gained only a small amount of weight (SGR 1.70 ¡Ó 0.20%/day). Growth was therefore affected by manganese and by the interaction of manganese and salinity, but not salinity alone. Manganese was found to accumulate in the gills, liver and muscle of the fish. No gill epithelial damage or other significant histological findings were found, however, significant differences in blood chemistry were observed. Blood sodium and chloride of manganese exposed fish were significantly elevated in hyperosmotic salinity (45 ppt) and depressed at hyposmotic salinity (5 ppt) compared with unexposed fish; consistent with manganese causing apoptosis or necrosis to chloride cells. Blood potassium was significantly elevated and liver potassium significantly reduced at all salinities in the presence of manganese. These findings are consistent with manganese interfering with carbohydrate metabolism. There were no differences in blood sodium, chloride or potassium across salinities in fish not exposed to manganese, demonstrating mulloway are capable of efficient osmoregulation across this salinity range.
160

Icke modellbaserad ekoföljning för radarnivåmätning / Echo tracking for tank gauging applications using non model based methods

Toverland, Anders January 2006 (has links)
<p>Denna rapport behandlar en fullständig metod för att följa, associera och klassificera ekospår. Vid radarnivåmätning ska ekon som härstammar ifrån samma fysikaliska objekt följas över tiden och klassificeras. Dagens radarnivågivare löser problemet genom konfiguration. Tankens geometri samt vilka störande objekt som finns anges vid installation.</p><p>Den framtagna metoden har delats upp i tre delmoment. Först binds individuella inmätta ekon samman till linjesegment. Dessa segment associeras samman till ekospår varefter dessa klassas fysikaliskt. Metoden kräver betydligt mindre konfiguration än den lösning som används för tillfället.</p> / <p>In this report a method for target tracking, association and classification of echo tracks in radar level gauges is discussed. In tank gauging echoes from the same physical object are called an echo track. The echoes must be tracked over time and classified. Currently radar level gauge units requires configuration to achieve classifications of echo</p><p>tracks. At installation tank geometry and disturbing echoes has to be registered.</p><p>The method has been divided into three parts. Firstly individual measured echoes are replaced by line segments. Association algorithms then create echo tracks from these segments. The third step is to classify these tracks physically. This method eliminates registering of disturbing echoes.</p>

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