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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.
11

Kampen om allmänningarna  i fyra värmländska socknar under frihetstiden

Hammarén, Lars January 2020 (has links)
This paper is about the dissolution and privatization of parish commons in 18:th century Sweden. The study focuses on four parishses (Hammarö, Väse, Ölme and Lungsund) all of them situated in the south of Värmland County. This is a region where ironworks were especially important for the eco-nomy of Sweden. The Ironworks required a lot of forest resources, of which there were a lot on the commons. This need resulted in a struggle for the resources between the ironworks and the peasants who needed it for their buildings, firewoods and pastures. With support of the state, the ironworks got parts of the commons for their supply of wood raw material.    However, this also resulted in an increased pressure on the remaining parts of the commons which the peasants could continue to use for their individual needs. The competition among the peasants led to troubles and mismanagement of the forests in the commons. In this situation, peasants who were well - off (’skattebönder’), began to work for division and privatization of the commons. The primary aim of this study is to analyze how and why this process of privatization took place. Which were the driving forces, and which were the role of different actors – the state, the aristocracy, the industrialists and different groups among the peasants – in this process?    Privatization of commonable lands in Sweden usually occurred in connection with the enclosure which in Sweden took place from the end of the 18:th century. However, In this study I have found that in at least two of the parishes, the division and privatization occurred about half a century before that enclosure, namely around 1742.    In this paper I also point to the striking similarities between the problems that occurred in these parishes and problems that always arise in commons in all areas. This problem has been discussed by authors like Garret Hardin and Ellinor Ostrom, among many others. Problems that has given rise to the concept ‘the tragedy of the commons’.
12

Artificial Neural Network-Based Approaches for Modeling the Radiated Emissions from Printed Circuit Board Structures and Shields

Kvale, David Thomas January 2010 (has links)
No description available.
13

Multi-Scale Thermal Modeling Methodology for High Power-Electronic Cabinets

Burton, Ludovic Nicolas 24 August 2007 (has links)
Future generation of all-electric ships will be highly dependent on electric power, since every single system aboard such as the drive propulsion, the weapon system, the communication and navigation systems will be electrically powered. Power conversion modules (PCM) will be used to transform and distribute the power as desired in various zone within the ships. As power densities increase at both components and systems-levels, high-fidelity thermal models of those PCMs are indispensable to reach high performance and energy efficient designs. Efficient systems-level thermal management requires modeling and analysis of complex turbulent fluid flow and heat transfer processes across several decades of length scales. In this thesis, a methodology for thermal modeling of complex PCM cabinets used in naval applications is offered. High fidelity computational fluid dynamics and heat transfer (CFD/HT) models are created in order to analyze the heat dissipation from the chip to the multi-cabinet level and optimize turbulent convection cooling inside the cabinet enclosure. Conventional CFD/HT modeling techniques for such complex and multi-scale systems are severely limited as a design or optimization tool. The large size of such models and the complex physics involved result in extremely slow processing time. A multi-scale approach has been developed to predict accurately the overall airflow conditions at the cabinet level as well as the airflow around components which dictates the chip temperature in details. Various models of different length scales are linked together by matching the boundary conditions. The advantage is that it allows high fidelity models at each length scale and more detailed simulations are obtained than what could have been accomplished with a single model methodology. It was found that the power cabinets under the prescribed design parameters, experience operating point airflow rates that are much lower than the design requirements. The flow is unevenly distributed through the various bays. Approximately 90 % of the cold plenum inlet flow rate goes exclusively through Bay 1 and Bay 2. Re-circulation and reverse flow are observed in regions experiencing a lack of flow motion. As a result high temperature of the air flow and consequently high component temperatures are also experienced in the upper bays of the cabinet. A proper orthogonal decomposition (POD) methodology has been performed to develop reduced-order compact models of the PCM cabinets. The reduced-order modeling approach based on POD reduces the numerical models containing 35 x 109 DOF down to less than 20 DOF, while still retaining a great accuracy. The reduced-order models developed yields prediction of the full-field 3-D cabinet within 30 seconds as opposed to the CFD/HT simulations that take more than 3 hours using a high power computer cluster. The reduced-order modeling methodology developed could be a useful tool to quickly and accurately characterize the thermal behavior of any electronics system and provides a good basis for thermal design and optimization purposes.
14

A reassessment of the role of animals at the Etton Causewayed Enclosure

Parmenter, Philippa Claire Rousell January 2014 (has links)
In recent years, causewayed enclosures have come to be regarded as being ceremonial or ritual sites. This classification is derived from a perceived lack of evidence pertaining to domestic settlement, in the form of houses and 'typical' domestic animal bone assemblages, and a perceived abundance of 'atypical' material and methods of deposition. This thesis explores the animal bone from the Etton causewayed enclosure in order to ascertain whether these perceptions have an empirical basis. Etton was excavated in the 1980s, and the published literature relating to the site appeared to conform to the stereotypes established for causewayed enclosure sites, however during preliminary analysis, it became clear that the animal bone data was not complete and that many of the inferences regarding the role of animals at Etton were the result of presumption or data being taken out of context. Specifically, this thesis looks at the nature of the fractures on the animal bones from Etton, and also from a similar causewayed enclosure at Staines in order to establish a clear taphonomic history for the faunal remains on the site, from which aspects of the role of animals can be deduced. In archaeological literature the absence of 'fresh', or helical fractures (which tend to result from the conscious decision to break a bone for marrow) is said to support the hypothesis that sites of this type were not domestic in nature. This assertion has been made despite the fact that no detailed studies into bone fracture at Neolithic sites have ever been undertaken. This thesis demonstrates that at both Etton and Staines, fresh fractures were abundant and considers the potential implications of this for these sites. In so doing it highlights the dangers of presuming evidence exists or does not exist, and of cherry-picking data to fit a preordained ideal rather than allowing the data to speak for itself. At Etton and Staines, the animal bone speaks not necessarily of a categorically ceremonial or ritual economy, divorced from the domestic economy of the time, but of a more mundane economy, with occasional 'atypical' activity, that was standard for the inhabitants of causewayed enclosures, whether at this type of site or elsewhere.
15

A Comparative Study of Climate Based Design of Building Enclosures

McGlohn, Emily, McGlohn, Emily January 2012 (has links)
This thesis attempts to determine if misconception about vapor retarders and air barrier systems affects building enclosure design and construction. Literature on this subject is continually evolving and often contradictory, supporting confusion. A survey of designers and builders representing four climate zones within the United States was done. Respondents disclosed where they learned about building enclosures and shared how clear or confusing they think the resources are on this subject and also weighed in on a few basic principles about enclosure design. Results show that most building professionals learn about enclosures through experience or a colleague. The internet is the first written resource they use when questions arise. The most significant misconceptions identified are that in some cases vapor retarder placement does not follow accepted building science or code requirements and that a portion of respondents only consider the air barrier system the vertical surfaces of an enclosure.
16

Convecção natural em cavidade quadrada com sólido interno aquecida e resfriada pelas paredes adjacentes / Natural convection in a square enclosure heated and cooled at the adjacent walls with an internal conducting body

Lima, Thiago Parente, 1983- 25 August 2018 (has links)
Orientador: Marcelo Moreira Ganzarolli / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-25T19:25:21Z (GMT). No. of bitstreams: 1 Lima_ThiagoParente_D.pdf: 4552077 bytes, checksum: 0daf2dd559f652d5de2d91531c795a2d (MD5) Previous issue date: 2014 / Resumo: A convecção natural em cavidades é um dos problemas fundamentais da transferência de calor. Nesse trabalho é estudada a transferência de calor conjugada em uma cavidade quadrada aquecida e resfriada por paredes adjacentes e com um sólido condutor inserido em seu centro. O tamanho e condutividade do sólido no interior da cavidade são caracterizados pelos parâmetros adimensionais ? e k*, definidos pela razão entre as dimensões do bloco e da cavidade, W/L, e a razão entre as condutividades do sólido e fluido, ks/kf, respectivamente. O efeito do bloco na transferência de calor da cavidade é investigado a partir de um estudo paramétrico abrangendo a faixa de número de Rayleigh (Ra) de 10^3 a 10^6, ? de 0,1 a 0,9, k* de 0,001 a 100 e número de Prandtl de 0,7 e 7,0. Os resultados são obtidos a partir da solução numérica das equações governantes e apresentados na forma de número de Nusselt, isolinhas de temperatura, função corrente e de calor. A transferência de calor na cavidade é governada pelo número de Rayleigh, tamanho e condutividade do bloco. O número de Prandtl, dentro da faixa investigada, mostrou pouca influência nos resultados. Nas cavidades com blocos de tamanho ?<0,3 a transferência de calor na cavidade apresenta as mesmas características da cavidade sem bloco, com o número de Nusselt sendo função apenas de Rayleigh. Para blocos maiores, o comportamento do Nusselt passa a depender também do tamanho e condutividade do bloco. De forma geral, para ?>0,8 e k*>10, a influência de Rayleigh na transferência de calor é bastante reduzida e o regime de transferência de calor na cavidade se aproxima do limite de condução pura. Na cavidade aquecida por baixo, a transferência de calor pode ser aumentada com relação à cavidade sem bloco quando um bloco de baixa condutividade é inserido. O aumento relativo do Nusselt na cavidade aquecida por baixo é observado para 10^5?Ra?10^6 e 0,4 / Abstract: Natural convection in enclosures is a fundamental problem in heat transfer. In this work the conjugate heat transfer in a square enclosure heated and cooled at the adjacent walls with an internal conducting solid body is studied. In order to characterize the size and thermal conductivity of the internal solid, the dimensionless parameters ? and k* are defined as the ratio of the solid and enclosure dimensions, W/L, and the solid and fluid conductivities, ks/kf, respectively. The effect of the block on the enclosure heat transfer is investigated in a range of the Rayleigh number (Ra) from 10^3 to 10^6, ? from 0.1 to 0.9, k* from 0.001 to 100 and Prandtl number of 0.7 and 7.0. The results are reported in the form of averaged Nusselt numbers, isotherms, streamlines and heatlines. The heat transfer process in the enclosure is governed by the Rayleigh number, solid size and thermal conductivity. The Prandtl number, in the range evaluated, shows little influence on the results reported. For dimensionless block sizes of ?<0.3, the heat transfer in the enclosure is not affected by the block and the Nusselt number remains a function of the Rayleigh number. As the block size increases, the Nusselt number becomes also dependent of the block size and its thermal conductivity. In the range of ?>0.8 and k*>10, the Nusselt number dependence on the Rayleigh number weakens and the enclosure heat transfer approximates of the pure conduction limit. In the enclosures heated from below the Nusselt number, in comparison with that with no solid body, is enhanced by a centered low conductivity solid body. The increase of Nusselt number is observed in the range of 10^5?Ra?10^6 and 0.4 / Doutorado / Termica e Fluidos / Doutor em Engenharia Mecânica
17

Numerical Study Of Combined Transport Processes In An Enclosure

Narasimham, G S V L 08 1900 (has links) (PDF)
No description available.
18

Foraging Decisions of Nocturnal Mice Under Direct and Indirect Cues of Predation Risk

Capers, Robbin G 26 June 2010 (has links)
The perception of increased predation risk by nocturnal mice and other small mammals has been shown to reduce activity levels, particularly in foraging effort. Various cues of predation risk have been used in previous studies, but few have assessed the potential interactions between different types of cues. I conducted field, laboratory, and enclosure experiments using predator scents, artificial light, and microhabitat variables to determine the effects of direct and indirect cues of predation risk on foraging behavior in wild nocturnal mice. Experimental foraging trays served as artificial resource patches, and giving-up densities were measured in order to test for foraging persistence in patches exposed to cues of predation risk. Cotton mice (Peromyscus gossypinus) were used in laboratory and enclosure trials, and were the most common mice present at the sites used for field trials. Although previous foraging studies have used other Peromyscus species, this species has not been tested, but ranges over densely populated areas of the United States where artificial light could potentially affect its behavior. In outdoor and laboratory enclosures, cotton mice showed no aversive response to bobcat urine, cloths rubbed on cats, or snake sheds, but did exhibit avoidance of cat fur and artificial light. In the field experiment, mice showed a strong preference for covered microhabitats, but did not avoid bobcat urine or artificial light. Foraging in artificial resource patches also increased throughout the duration of the field experiment, possibly coinciding with a reduction in naturally-available forage. Mice in this population appear to use cover as their primary means of avoiding detection or capture by predators, though they do avoid artificial light and at least one fur-derived odor when their available options for escape are reduced.
19

Distance to the Border in Spatial Point Patterns

Joyner, Michele, Ross, Chelsea, Seier, Edith 01 November 2013 (has links)
The analysis of spatial point patterns is commonly focused on the distances to the nearest neighbor. The distance of organisms to the edge of the enclosure is also of interest in some biological studies performed in the laboratory. We define the B (border) function and derive its shape assuming complete spatial randomness (CSR) for square, rectangular, circular, and some three-dimensional arenas. The idea is then extended outside the laboratory setting to work with maps and points located in geographical regions. Commands in R ( R Core Team, 2012) to calculate and plot the empirical B̂ function are included. The B function, based on distances to the nearest edge, in addition to the G function, based on distances to the nearest neighbor, contributes to the understanding of the spatial distribution of the points.
20

Distance to the Border in Spatial Point Patterns

Joyner, Michele, Ross, Chelsea, Seier, Edith 01 November 2013 (has links)
The analysis of spatial point patterns is commonly focused on the distances to the nearest neighbor. The distance of organisms to the edge of the enclosure is also of interest in some biological studies performed in the laboratory. We define the B (border) function and derive its shape assuming complete spatial randomness (CSR) for square, rectangular, circular, and some three-dimensional arenas. The idea is then extended outside the laboratory setting to work with maps and points located in geographical regions. Commands in R ( R Core Team, 2012) to calculate and plot the empirical B̂ function are included. The B function, based on distances to the nearest edge, in addition to the G function, based on distances to the nearest neighbor, contributes to the understanding of the spatial distribution of the points.

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