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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.
1

Middle and Late Neolithic Enclosures in Britain

Gibson, Alex M. January 2014 (has links)
No / This paper outlines the types, developments and relationships of British enclosures in the middle and later Neolithic.
2

The dynamic modelling and testing of a vortex amplifier of low aspect ratio

Mo, Ronnie Sai-Yan January 1988 (has links)
No description available.
3

An Elephant Never Forgets ... The Right Microclimate : Thermal Comfort and Microclimatic Design of Asian Elephant Zoo Enclosures

Crawford, Erin 15 January 2013 (has links)
An animal’s ability to find thermal comfort can be can be limited within a zoo enclosure. This creates a need to design comfortable microclimates for the animal within their enclosure space. This is an exploratory study intended to investigate the relationships between an elephant’s movements throughout their space and the microclimatic conditions within its zoological enclosure. By outlining an understanding of microclimates and how they are affected by the landscape combined with knowledge of elephant behaviours it will be possible design or plan for microclimatic use within zoo enclosures. Observational data were collected from five Asian elephants (Elephas maximus). The movements of the elephants were monitored along with the use of microclimates within their enclosure. Thermal regulatory movements involving microclimatic use typically involved water and shade use, however evidence suggests that the animals were also avoiding terrestrial radiation from some of the gunite walls. It is important that animals are given the opportunity to find microclimates within the space to regulate their body temperature. Designing landscapes that incorporate microclimates within their habitats is crucial to the welfare and health of zoo elephants.
4

Innovative Bauern : Einhegungen, Bewässerung und Waldteilungen im Kanton Luzern im 16. und 17. Jahrhundert /

Ineichen, Andreas. January 1996 (has links)
Diss.--Philosophische Fakultät I--Universität Zürich, 1996. / Bibliogr. p. 257-272. Index.
5

Interactions Among Coexisting Larval Odonata: An in Situ Experiment Using Small Enclosures

Benke, Arthur C., Crowley, Philip H., Johnson, Dan M. 01 September 1982 (has links)
Field experiments using small replicated enclosures focused on interactions between larval populations of Epitheca cynosura and Ladona deplanata (Odonata: Anisoptera) - two species that emerge in early spring. The presence of Epitheca reduced the total biomass of Ladona, but Ladona had no significant effect on Epitheca. These early-emerging species reduced the biomass of small instars of late-emerging Anisoptera which colonized enclosures during the experiments; and the late-emerging Anisoptera seem to have inhibited colonization by Zygoptera larvae. Results are consistent with the importance of predatory (cannibalism or mutual predation) interactions in this community.
6

Convecção natural em cavidades triangulares /

Aquino, Felipe Rinaldo Queiroz de. January 2001 (has links)
Orientador: Maurício Araújo Zanardi / Resumo: Neste trabalho estuda-se a convecção natural laminar em regimes permanente e transiente em cavidades triangulares isósceles. Para a determinação das distribuições de velocidades e temperaturas são utilizadas as equações de conservação da massa, quantidade de movimento e de energia, com a aproximação de Boussinesq. A solução do sistema de equações diferenciais é feita através de um método de volumes finitos utilizando o esquema de discretização "Power-Law" proposto por Patankar e o procedimento SIMPLE é empregado para obtenção de equações de correção de pressões. Os sistemas de equações algébricas encontrados são solucionados numericamente por um algoritmo "line-by-line", que é uma combinação de um método direto TDMA para problemas unidimensionais com o método iterativo de Gauss-Siedel. Foram obtidas soluções para diversas combinações de condições de contorno de temperaturas conhecidas e paredes adiabáticas e as comparações com os resultados existentes na literatura comprovam a confiabilidade do modelo e do código computacional desenvolvidos. São apresentadas ainda soluções quando se consideram fluxos de calor constantes e variáveis com o tempo em uma das superfícies da cavidade. A influência do valor do número de Grashof e da razão de aspecto da cavidade é também discutida. / Abstract: In this work the laminar natural convection in enclosures of isosceles triangular shape is studied. Both the steady state and the transient regimes are included. The mass conservation, momentum and energy equations are used for the velocity and temperature profiles determination. The Boussinesq approach is also considered. The solution of the differential equation set is performed by using a finite volume method. The discretization scheme chosen was the Patankar's Power-Law Scheme and the SIMPLE algorithm is adopted to get a pressure correction equation. The resultant algebraic equations are solved by a line-by-line procedure that is a combination of a direct method (TDMA) and an iterative Gauss-Siedel method. The solution for some different boundary condition, involving prescribed temperatures and adiabatic walls, were obtained and were compared with the literature results. The good agreement between them validates the developed mathematical model and computational code. Here it is also presented solutions for the case of a constant or time dependent heat flux imposed over one of the sides of the enclosure. The influence of the Grashof number and the enclosure aspect ratio is discussed. / Doutor
7

DESIGN OF PARTIAL ENCLOSURES FOR ACOUSTICAL APPLICATIONS

Carter, Amy Elizabeth 01 January 2006 (has links)
Enclosures are a very common way to reduce noise emissions from machinery. However, enclosures display complex acoustic behavior that is difficult to predict. The research presented in this thesis uses the boundary element method in order to better understand the acoustic behavior of a partial enclosure. Insertion loss was used as the performance measure and the effect of several design factors on the overall insertion loss was documented. Results indicate that the most important factors affecting enclosure performance are the opening size, amount of absorption, and the source-to-opening distance.
8

Shielding characteristics of a commercial 19-inch rack-based cabinet

Chen, Jue, January 2007 (has links) (PDF)
Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed February 5, 2008) Includes bibliographical references (p. 82).
9

Experimentally validated multiscale thermal modeling of electronic cabinets

Nie, Qihong. January 2008 (has links)
Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Joshi, Yogendra; Committee Member: Gallivan, Martha; Committee Member: Graham, Samuel; Committee Member: Yeung, Pui-Kuen; Committee Member: Zhang, Zhuomin. Part of the SMARTech Electronic Thesis and Dissertation Collection.
10

Convecção natural em cavidades triangulares

Aquino, Felipe Rinaldo Queiroz de [UNESP] January 2001 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2001Bitstream added on 2014-06-13T18:42:36Z : No. of bitstreams: 1 aquino_frq_dr_guara.pdf: 1771311 bytes, checksum: ae592e11d2c944ae8a940fa51ec488cf (MD5) / Neste trabalho estuda-se a convecção natural laminar em regimes permanente e transiente em cavidades triangulares isósceles. Para a determinação das distribuições de velocidades e temperaturas são utilizadas as equações de conservação da massa, quantidade de movimento e de energia, com a aproximação de Boussinesq. A solução do sistema de equações diferenciais é feita através de um método de volumes finitos utilizando o esquema de discretização Power-Law proposto por Patankar e o procedimento SIMPLE é empregado para obtenção de equações de correção de pressões. Os sistemas de equações algébricas encontrados são solucionados numericamente por um algoritmo line-by-line, que é uma combinação de um método direto TDMA para problemas unidimensionais com o método iterativo de Gauss-Siedel. Foram obtidas soluções para diversas combinações de condições de contorno de temperaturas conhecidas e paredes adiabáticas e as comparações com os resultados existentes na literatura comprovam a confiabilidade do modelo e do código computacional desenvolvidos. São apresentadas ainda soluções quando se consideram fluxos de calor constantes e variáveis com o tempo em uma das superfícies da cavidade. A influência do valor do número de Grashof e da razão de aspecto da cavidade é também discutida. / In this work the laminar natural convection in enclosures of isosceles triangular shape is studied. Both the steady state and the transient regimes are included. The mass conservation, momentum and energy equations are used for the velocity and temperature profiles determination. The Boussinesq approach is also considered. The solution of the differential equation set is performed by using a finite volume method. The discretization scheme chosen was the Patankar's Power-Law Scheme and the SIMPLE algorithm is adopted to get a pressure correction equation. The resultant algebraic equations are solved by a line-by-line procedure that is a combination of a direct method (TDMA) and an iterative Gauss-Siedel method. The solution for some different boundary condition, involving prescribed temperatures and adiabatic walls, were obtained and were compared with the literature results. The good agreement between them validates the developed mathematical model and computational code. Here it is also presented solutions for the case of a constant or time dependent heat flux imposed over one of the sides of the enclosure. The influence of the Grashof number and the enclosure aspect ratio is discussed.

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