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Formation, cultural use and management of Icelandic wet meadows : a palaeoenvironmental interpretationBarclay, Rebecca January 2016 (has links)
This thesis offers the first detailed palaeoenvironmental analysis of wetland areas within sub-Arctic enclosed homefield’s. Significance of meadows were previously mentioned only briefly in the literature, suggesting influences in settlement site selection as well as importance in quality fodder production, producing up to two thirds of total hay resources in a somewhat marginal agricultural landscape. Given the importance of hay resources in Iceland it seems unusual these areas have received so little attention to date, despite extensive research on all other aspects of the Norse farm system. The organic sediments within the meadows, given their development in-situ over extended time periods, have the ability to record aspects of the intimate relationship between societal and environmental change, and so in a robust and holistic way our methods set integrates radiocarbon measurement, tephrochronology, palynology and thin section micromorphology from the same core; reflecting these findings against existing paleoclimate and archaeological site data. This combined application of the core techniques – palynology and soil micromorphology, has proven successful in creating effective human ecodynamic records from each of the study farms. Records obtained from the three farm sites in northwest and northern Iceland exposed the varying importance and differing utilisation of these wetland areas. Meadows would appear to have played an import role in choice of settlement site across northern Iceland, through the provision of open areas, and additional and immediately available fodder resources at settlement, in a landscape dominated by dense scrub. Meadows were found to have been in continuous use, albeit at varying levels of intensity, from settlement to the present day. In this respect the semi-natural resources are found to be remarkably resilient, demonstrating little alterations to their composition following severe climatic downturns, including that of the Little Ice Age, and volcanic eruption. Acting as a robust resource and safety buffer for settlements, contributing to fodder resources where reliability of other resources is jeopardised by environmental conditions. Research in the more marginal northwest peninsula provides the first evidence of artificially created wet meadows in Iceland, developed to give sustained fodder production for over-wintering livestock in an environment that inherently had a short growing season and lacked soil fertility. A further example of the nuanced land management practices adopted in the agriculturally fragile farmscapes of the Norse North Atlantic. The findings of the thesis have wider implications for understanding the emergence of resilient and sustainable communities in agriculturally marginal environments; to this end there remains many opportunities to use palaeoenvironmental research to study ecosystem responses to natural and anthropogenic stresses, giving us a better understanding of capacities to withstand future stresses.
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A composite manufacturing process for producing class A finished components / Zelldra LombardLombard, Zelldra January 2014 (has links)
The purpose of this study was to develop a composite manufacturing process that would be able to deliver Class A surface finished products in the context of mould manufacturing methods. The problem required solving was to overcome the time needed to prepare Class A surfaces, by developing a composite manufacturing process that will deliver Class A surface finished products straight from the mould. The process was aimed at the entire development process, from mould and plug design up to the finished product.
A literature study and a factory mould survey were conducted with a view to obtain the necessary insights into surface finishing and composite manufacturing. These surveys were followed by seven constructional tests which determined the most appropriate solutions for the proposed manufacturing processes.
Test 1 was used to determine a quality finish standard for composites from the sanding grits used to finished composite surfaces versus surface roughness values used in other industries. The standard determined that a P800 finish has a roughness between 0.200 and 0.150 um and constitutes a Class A3 finish. P1000 to P1200 have a roughness between 0.150 um to 0.100 um and constitutes a Class A2 finish. Finally a P2000 and higher have a roughness of 0.100 um and lower and constitutes Class A1 surface finish. After the standard was set, the tests for finishing of the moulds, plugs and parts commenced.
Test 2 was conducted on the CNC manufacturing of plugs out of Nuceron651 tooling board. Tool path parameters were varied in a matrix. The samples with the best surface finish value were cut with a step-over of 0.5 and feed of 800 mm/min. These parameters were found to be the most influential. Test 2 and 4 revealed that the plug surface finishing should commence with conventional 2K paint finishing, with a possibility of acrylic split surface. This process produced projected mould surfaces between 0.150 um and 0.200 um, which can be categorised as Class A-3.
Test 5 and 6 determined methods for improving the mould surface quality and durability. It was established that the tooling gelcoat should be applied whilst being heated and backed with at least two layers of glass veil and a steady increase of GSM of structural glass fibres to prevent print-through. Test 3 determined that the mould corners could be strengthened with rovings pressed into the corner. It was also established that the moulds surfaces will require finishing after demoulding.
The final moulds were manufactured from a fibreglass composite structure with tooling gelcoat surface. A number of guidelines and a set process were developed in order to produce moulds with a surface finish of average 0.9 um, equivalent to Class A1. Release agents were tested in Test 7, and the Loctite Frekote 770-NC release system was deemed appropriate for use with In Mould Coating (IMC) of 2K Paint. These elements were all synthesised into plug, mould and part manufacturing processes.
The proposed processes were validated by the manufacturing of a JS instrument panel, which delivered a Class A2, 0.175 um, finish with IMC of 2K paint. With only a minor sanding of P3000 grit and polishing, the part was made into a Class A1 surface, measured at 0.63 um.
The study proved that it is possible to produce Class A finished part with IMC. This method can provide a solution aimed at the elimination of P600 and lower finishing of composite parts manufactured with IMC. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014
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A composite manufacturing process for producing class A finished components / Zelldra LombardLombard, Zelldra January 2014 (has links)
The purpose of this study was to develop a composite manufacturing process that would be able to deliver Class A surface finished products in the context of mould manufacturing methods. The problem required solving was to overcome the time needed to prepare Class A surfaces, by developing a composite manufacturing process that will deliver Class A surface finished products straight from the mould. The process was aimed at the entire development process, from mould and plug design up to the finished product.
A literature study and a factory mould survey were conducted with a view to obtain the necessary insights into surface finishing and composite manufacturing. These surveys were followed by seven constructional tests which determined the most appropriate solutions for the proposed manufacturing processes.
Test 1 was used to determine a quality finish standard for composites from the sanding grits used to finished composite surfaces versus surface roughness values used in other industries. The standard determined that a P800 finish has a roughness between 0.200 and 0.150 um and constitutes a Class A3 finish. P1000 to P1200 have a roughness between 0.150 um to 0.100 um and constitutes a Class A2 finish. Finally a P2000 and higher have a roughness of 0.100 um and lower and constitutes Class A1 surface finish. After the standard was set, the tests for finishing of the moulds, plugs and parts commenced.
Test 2 was conducted on the CNC manufacturing of plugs out of Nuceron651 tooling board. Tool path parameters were varied in a matrix. The samples with the best surface finish value were cut with a step-over of 0.5 and feed of 800 mm/min. These parameters were found to be the most influential. Test 2 and 4 revealed that the plug surface finishing should commence with conventional 2K paint finishing, with a possibility of acrylic split surface. This process produced projected mould surfaces between 0.150 um and 0.200 um, which can be categorised as Class A-3.
Test 5 and 6 determined methods for improving the mould surface quality and durability. It was established that the tooling gelcoat should be applied whilst being heated and backed with at least two layers of glass veil and a steady increase of GSM of structural glass fibres to prevent print-through. Test 3 determined that the mould corners could be strengthened with rovings pressed into the corner. It was also established that the moulds surfaces will require finishing after demoulding.
The final moulds were manufactured from a fibreglass composite structure with tooling gelcoat surface. A number of guidelines and a set process were developed in order to produce moulds with a surface finish of average 0.9 um, equivalent to Class A1. Release agents were tested in Test 7, and the Loctite Frekote 770-NC release system was deemed appropriate for use with In Mould Coating (IMC) of 2K Paint. These elements were all synthesised into plug, mould and part manufacturing processes.
The proposed processes were validated by the manufacturing of a JS instrument panel, which delivered a Class A2, 0.175 um, finish with IMC of 2K paint. With only a minor sanding of P3000 grit and polishing, the part was made into a Class A1 surface, measured at 0.63 um.
The study proved that it is possible to produce Class A finished part with IMC. This method can provide a solution aimed at the elimination of P600 and lower finishing of composite parts manufactured with IMC. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014
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MODELING OF THE SURFACE ATTENUATION EFFECTS OF RAIN ON COMPOSITE ANTENNA STRUCTURES AT KA-BANDBorsholm, Atle 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / During the NASA Ka-band propagation experiment it was discovered that rainwater on the antenna caused significant attenuation. It is necessary to estimate the losses caused by water on the antenna in order to separate these losses from the atmospheric propagation losses. A prediction model is developed for losses caused by rainwater on a satellite dish antenna. The model is based entirely on physical parameters including elevation angle, dish diameter, focal length, properties of present coating layers, feed window properties, frequency, polarization, water temperature and rain rate. The prediction model is implemented using Matlab and has been tested against experimental data.
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Wet/Dry Mapping - Reference Maps (separate Start and End maps)Underwood, Brian 06 1900 (has links)
A collection of reference maps for volunteers to use during data collection. Each map provides a detailed (zoomed in .5x1 mi.) view of where this particular section ends.
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Polymeric stabilizers maintaining the supersaturation solubility of itraconazole nanocrystals after dissolution processKubačková, Jana January 2016 (has links)
Title of thesis: Polymeric stabilizers maintaining the saturation solubility of itraconazole nanocrystals after dissolution process Author: Jana Kubačková Department: Pharmaceutical Technology Supervisor: PharmDr. Ondřej Holas, Ph.D. Specialized supervisor: Assoc. Prof. Leena Peltonen, Ph.D. The increase of bioavailability of poorly water soluble drugs is still an issue. One of the techniques improving aqueous drug substance solubility, and consequently enhancing bioavailability, is formation of nanoparticles. However, the bioavailability is determined by the concentration of the dissolved drug achieved at the time of absorption. This fact emphasizes the importance of the maintenance of the high solubility until the absorption area is reached. Sufficiently stabilised nanocrystalline drugs offer a solution to this problem. In this thesis, the solid nanoparticle formations of an antifungal agent itraconazole (ITZ) are presented. Wet milling was employed to create the nanosuspension stabilised by binary mixture of stabilisers or by a single stabiliser. An aggregation inhibitor Poloxamer 407 (F127) in the combination with a polymeric precipitation inhibitor hydroxypropyl methylcellulose (HPMC) or polyvinyl pyrrolidone (PVP) at different ratios, or a single precipitation inhibitor, were utilised. The...
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The potential for accident reduction by improving urban skid resistance levelsYoung, Arthur Edward January 1985 (has links)
The problem of providing adequate wet-road skid resistance on urban roads has received relatively little attention from highway maintenance authorities. This study is an assessment of the potential for reducing accident rates by improving skid resistance levels on such roads. Reasons for the neglect of urban skid resistance are discussed and an assessment made of the scale of the skidding problem in this context. Evidence is presented to demonstrate that the potential for accident reduction is greater than is indicated by the statistics for reported skidding accidents. The pattern of frictional demand and the measurement of skid resistance are discussed, as are the technical difficulties associated with maintaining good skid resistance on heavily-trafficked roads. The performance of conventional surfacing materials is assessed and recently-developed materials are evaluated. It is suggested that the attainment of high skid resistance is inhibited by economic rather than technical factors. Nationally-proposed standards for skid resistance are examined and modifications are suggested for urban use. The problem of defining accident risk at an individual site is examined and the relationship between accident rate and skid resistance investigated using regression techniques with data from the Greater London area. Criteria are developed for identifying sites where an improvement in skid resistance is likely to be effective in reducing accidents and consideration is given to the economic justification for skid resistance improvements. Alternative strategies are considered and a policy is proposed which would be practicable and cost-effective and, it is argued, could lead to a substantial reduction in accident rates.
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Modelling the pharmacokinetics and pharmacodynamics of macromolecules for the treatment of wet AMDHutton-Smith, Laurence January 2018 (has links)
Wet age related macular degeneration (wet AMD) is a highly debilitating retinal disease, the third leading cause of blindness in the world and one the most expensive ocular conditions to care for. Wet AMD is characterised by the proliferation of neovasculature through the retinal posterior and theorised to be, at least in part, induced and driven by excess vascular endothelial growth factor (VEGF). Many current treatments for wet AMD utilise anti-VEGF macromolecules that bind to VEGF. The retina, however, remains a largely inaccessible, and delicate, anatomical region. Due to difficulties in collecting clinical and experimental data, mathematical modelling is playing an increasingly prominent role in understanding the distribution (Pharmacokinetics, PK) and drug-to-target interactions (Pharmacodynamics, PD) for treatments of wet AMD. This thesis will focus on ordinary/partial differential equation (ODE/PDE) models for the PK/PD of anti-VEGF therapeutics, administered via intravitreal (IVT) injection into the mammalian eye. We start in Chapter 2 with a 2-compartment PK/PD ODE model of drug-VEGF interactions in the eye, analysing a clinical dataset to estimate key binding parameters between VEGF and the typical anti-VEGF molecule, ranibizumab. In Chapter 3, we extend the PK ODE framework of the 2-compartment model to include a mechanistic description of the retina, to estimate retinal permeability to macromolecules used for treating wet AMD. In Chapter 4, using the retinal PK model, we reintroduce VEGF to predict concentrations of free VEGF in the retina post-IVT injection. Chapters 5 and 6 model a hypothetical class of anti-VEGF molecules designed to bind not only VEGF but also existing vitreal superstructures, analysing how dose and binding kinetics impact ocular retention. Alongside these models we present analogous PDE models, addressing whether the assumption that concentrations are homogeneous across anatomical regions, as implicit in ODE models, is appropriate for macromolecular PK/PD in the mammalian eye.
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A study of environmental education in Missouri a survey of project wet facilitators' understandings of environmental education /Long, Blaise Edward, January 2007 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 29, 2007) Vita. Includes bibliographical references.
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Dry Versus Wet Aging of Beef: Retail Cutting Yields and Palatability Evaluations of Steaks Using Alternative Cutting StylesSmith, Amanda 1987- 14 March 2013 (has links)
Boneless ribeye rolls (n = 12) and boneless top sirloin butts (n = 12) were obtained from heavy weight carcasses (mean = 407.8 kg), assigned to one of two aging treatments (dry or wet) and aged for 35 days at a commercial aging facility. Cutting tests were performed at the end of the aging period to determine retail yields. Subprimals were fabricated using the Beef Alternative Merchandising cutting styles, isolating four specific muscles: M. spinalis thoracis, M. longissimus thoracis, M. gluteobiceps, and M. gluteus medius. Retail cutting tests showed wet-aged subprimals had higher (P < 0.0001) total saleable yield percentages with decreased cooler shrink and gross cut loss percentages. This resulted in wet-aged ribeye rolls and top sirloin butts yielding 1.5 times and 1.3 times more saleable product than dry-aged counterparts, respectively. In order to determine palatability characteristics, consumer sensory evaluations and trained panel evaluations were preformed. Palatability related to aging and muscle type resulted in significant differences. From a consumer standpoint, aging treatment influenced OLIKE, FLAV, FLEVEL, and BEEFLIKE but only through the interaction of aging treatment x muscle. Clearly, consumers rated the wet-aged, M. spinalis thoracis highest in each of the previously stated attributes. Aging also affected JUIC, whereas muscle type had a significant (P < 0.0001) effect on FLVBF, TEND, LEVTEND, JUIC, and LEVJUIC. As far as trained sensory attributes were concerned, a more concrete flavor profile of aged beef was obtained. In addition, dry-aged steaks had greater (P < 0.0001) cooking yield percentages when compared to wet-aged steaks.
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