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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.
21

Development of a low temperature geothermal organic rankine cycle standard.

Taylor, Leighton John January 2015 (has links)
The growth in renewable electricity generation is forecast to continue as fossil fuel levels decrease and carbon dioxide emissions are penalized. The growth in geothermal is becoming constrained as conventional high-temperature sources are fully exploited. Geothermal can be a cost competitive base load power source. Governments and utilities are looking at the potential of electricity generation from low temperature geothermal resources for future development. This technology, unlike the high and medium temperature, is not mature and there are a number of companies looking at entering the Organic Rankine Cycle (ORC) market. This thesis aims to provide a necessary step for reliable commercial develop this technology by developing the first draft of a low temperature geothermal ORC standard. The standard outlines the critical stages of a geothermal ORC project as the Prospecting stage; Pre-Feasibility stage, Feasibility stage, and the Detailed Design stage. The standard is unlike other standards that are used to design one component; this standard guides the engineers though the various critical steps of the ORC design to correctly assess the geothermal resource and to inform design and investment decisions. The standard provides particular guidance on critical factors in ORC design, primarily the working fluid selection and component selection limitations. Experienced industry engineers have provided advice and insight regarding the critical design points and processes. The draft standard was reviewed by a number of geothermal industry engineers who have worked with large scale, conventional ORCs. They each commented on the standard from their prospective in the industry and gave general feedback was that it is a technically relevant standard that can be used as a potential start point to develop a new standard for the low temperature binary ORC industry. The final draft standard has been submitted to the ISO for consideration. This thesis first sets out the general background on the state of the art and the industry for lowtemperature binary ORC power plants, and provides the review assessment of the standard draft. However, the bulk of the thesis is the standard itself. The standard represents a substantial contribution to the mechanical and thermal systems engineering field.
22

DETAILED MODELING OF MUFFLERS WITH PERFORATED TUBES USING SUBSTRUCTURE BOUNDARY ELEMENT METHOD

Datchanamourty, Balasubramanian 01 January 2004 (has links)
Perforated tubes in mufflers are generally modeled by the transfer impedance approach since modeling the actual geometry of the perforated tubes with holes is very expensive due to the enormity of the boundary elements required. With the development of the substructuring technique which greatly reduces the number of elements required detailed modeling of the perforated tubes has become possible. In this thesis mufflers with perforated tubes are analyzed by modeling the actual geometry and locations of holes on the perforated tubes. The Direct-mixed-body boundary element method with substructuring is used to model the mufflers. Mufflers of various geometry containing perforated tubes with holes of different sizes and porosity are tested. The results obtained from the analyses are compared with the empirical formula results and experimental results. A preliminary investigation on the detailed modeling of flow-through catalytic converters is also conducted.
23

Kernel Selection for Convergence and Efficiency in Markov Chain Monte Carol

Potter, Christopher C. J. 24 April 2013 (has links)
Markov Chain Monte Carlo (MCMC) is a technique for sampling from a target probability distribution, and has risen in importance as faster computing hardware has made possible the exploration of hitherto difficult distributions. Unfortunately, this powerful technique is often misapplied by poor selection of transition kernel for the Markov chain that is generated by the simulation. Some kernels are used without being checked against the convergence requirements for MCMC (total balance and ergodicity), but in this work we prove the existence of a simple proxy for total balance that is not as demanding as detailed balance, the most widely used standard. We show that, for discrete-state MCMC, that if a transition kernel is equivalent when it is “reversed” and applied to data which is also “reversed”, then it satisfies total balance. We go on to prove that the sequential single-variable update Metropolis kernel, where variables are simply updated in order, does indeed satisfy total balance for many discrete target distributions, such as the Ising model with uniform exchange constant. Also, two well-known papers by Gelman, Roberts, and Gilks (GRG)[1, 2] have proposed the application of the results of an interesting mathematical proof to the realistic optimization of Markov Chain Monte Carlo computer simulations. In particular, they advocated tuning the simulation parameters to select an acceptance ratio of 0.234 . In this paper, we point out that although the proof is valid, its result’s application to practical computations is not advisable, as the simulation algorithm considered in the proof is so inefficient that it produces very poor results under all circumstances. The algorithm used by Gelman, Roberts, and Gilks is also shown to introduce subtle time-dependent correlations into the simulation of intrinsically independent variables. These correlations are of particular interest since they will be present in all simulations that use multi-dimensional MCMC moves.
24

Klimatanpassning ur ett sårbarhetsperspektiv : En studie hur klimatanassning sker i Uppsala / Climate adaptation from a vulnerability perspective : Case study of climate changeadaptation in Uppsala municipality.

Thomsson, Michaéla January 2014 (has links)
Bebyggda områden och byggnader har genom historien behövt anpassas för klimatet och vädret. Ibland är vädret mer extremt med stora mänder vatten eller vind. Med ett föränderligt klimat ändras förutsättningar för bebyggelse i städer som i Uppsala stad. Denna skrift behandlar dels kravbilden på kommuner avseende klimatförändringar och detaljplanering. Vidare studeras hur kommunen arbetar med frågan. Klimatförändringar kan gestaltas på flera sätt men denna studie studerar främst aspekter som berör översvämning. Det finns mycket kunskap och metoder att använda vid anpassning till ändrat väderklimat. Lagstiftning som berör detaljplanering och klimatförändring har analyserats. Vidare har intervjuer med tjänstemän verksamma inom Uppsala utförts för att får en bättre uppfattning om klimatanpassningsarbetet inom kommunen. Texten innehåller även en studie av valda detaljplaner, inom Uppsala kommun, som bedömts vara inom riskzon för översvmämning och erosion i urban miljö. Vid all urban planering är det en fråga om priotiteringar inom olika områden. Ibland uppnås synergieffekter, vilket framgår i några av valda detaljplaner. Men för att göra mer än vad lagstiftning kräver behöver fördelarna med klimatanpassning lyftas fram tydligare i organisationen och klimatanpassning måste oftare ses utifrån ett mer övergripande planeringsperspektiv än detaljplanenivå. / Climate change will affect local urban areas differently and society’s ability to handle changes depend in some part on what is considered in the planning process. This paper examines what the municipality is required to do regarding planning for and climate change. It then presents the results of a case study conducted in Uppsala municipality, which contains a study of approved planes in Uppsala town and interviews with employees at Uppsala municipality and region office. The results are that some aspects of climate change are more considered than other in this case study of urban planning. One can build houses in areas at risk but with the right precautions. There is potential to make society more adapted to climate change but it needs to be prioritized and located starting with planning for it.
25

超小型燃焼器の開発に関する詳細素反応機構を考慮した数値解析

YAMAMOTO, Kazuhiro, YAMASHITA, Hiroshi, SUZUKI, Shin, 山本, 和弘, 山下, 博史, 鈴木, 新 January 2008 (has links)
No description available.
26

センターエアーバーナによる燃焼器の小型化に関する数値解析

YAMAMOTO, Kazuhiro, YAMASHITA, Hiroshi, MAKITA, Yuichiro, 山本, 和弘, 山下, 博史, 槙田, 雄一郎 January 2009 (has links)
No description available.
27

Numerical Study on Spark Ignition Characteristics of Methane-air Mixture Using Detailed Chemical Kinetics : Effect of Electrode Temperature and Energy Channel Length on Flame Propagation and Relationship between Minimum Ignition Energy and Equivalence Ratio

YAMAMOTO, Kazuhiro, YAMASHITA, Hiroshi, HAN, Jilin January 2009 (has links)
No description available.
28

From page to page to stage translation and dramaturgy issues of Once upon a rainy night /

Xu, Junying. January 2008 (has links)
Thesis (M.A.)--Miami University, Dept. of Theatre, 2008. / Title from first page of PDF document. Includes bibliographical references (p. 70).
29

Realizace a zaměření sítě polohových a výškových bodů v povodí Jenín různými metodami. / Project and surveying of the network for planimetry and hight points in the area of the river Jenín using several methods.

SVOBODOVÁ, Lenka January 2010 (has links)
Dissertation was worked on the theme " Project and surveying of the network for planimetry and hight points in the area of the river Jenín using several methods". Target of this dissertation was building of point field, their planimetry and altitude destination like basis for another telemetry in range. On the basis of geodetic and map data was effected reconnaissance of the area, estimation of current point field, their completion to required density and locating new points by geodetic and GPS methods. It was built net of 16 points of the detailed planimetry point field and eight of them was subjekt of my dissertation. For planimetry and altitude survey by GPS method was used Trimble 4600LS device. By geodetic method points was located by electronic total station Leica TCR 407 power. Altitude of the three points was determined by the technical levelling using levelling machine Topcon AT {--} 22A and the other hights of points was calculated trigonometrically. Part of dissertation was processing of surveyed data, execution of graphic enclosure and comparing both methods.
30

Förtäta eller dö? : En studie av stadens översiktsplanering kontra färdigt resultat / Densify or die? : A study of the city's comprehensive planning versus the outcome

Apostolidis, Georgios January 2018 (has links)
Densification is a summary word to devote denser housing in the city centre, yet airy and varied. The goal is for more people to move to the city centre to live, work and perform all kinds of activities such as shopping, work out or just go out and have a good time. Karlstad's vision is densification with a living and growing centre as a goal, as well as well-functioning public transport for commuters from near and far. Extended housing and activities with environmental thinking and well-being as well as more jobs are the goals the municipality wants to achieve with densification. Hence, the study partakes attempts to evaluate how Karlstad municipality's detailed plans are in line with today's six-year-old general plan visions regarding densification. This is done by a categorization based on an article from Boyko & Cooper 2011 that created a summary of several researchers' views regarding the concept of densification and its inclusion. Here, compromises have been made by putting interesting theories against each other to make as fair a review as possible. An account of theories leads to reclarification of parts of the material to realize the current densification. The result of my study shows densification as something active that takes place in cities, either by increasing or getting closer to people or housing. How the densification is visualized or not determines the established extent shifts, but something that is often encountered is the accumulation of built-in surface, the number of people in a certain place or the proportion of a specific spatial space that has been built. Karlstad describes densification and it is also something that is exemplified, however, if the starting point is that increased possibilities for more people to choose public transport should not be considered implemented based on my study. Furthermore, there is a description of how Karlstad wants to densify with focus on the central parts to further grow beyond what cannot be noted in the detailed plans discussed. To some extent, Karlstad creates densification, but if it in turn leads to increased opportunities for individuals to use more sustainable alternatives to relocation should not be considered realized. Karlstad's vision of building inside and out is not infused, and the densification described in the overview plan has not given an impression in the detailed plans adopted today

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