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Varma, Nitin. "Producing tea coolies?" Doctoral thesis, Humboldt-Universität zu Berlin, Philosophische Fakultät III, 2013. http://dx.doi.org/10.18452/16859.
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Als "Coolie" gilt gemeinhin der "ungelernte" Arbeiter. Das Anbieten von Leiharbeit hatte diverse präkoloniale Vorläufer. Im 19. Jahrhundert wurde der Versuch unternommen, den Begriff des "Coolies" durch diskursive Auslegungen und die Methoden einer "flexiblen-inflexiblen" Arbeit neu zu prägen. "Coolie"-Arbeit galt meist als ein Kompromiss zwischen der Vergangenheit (Sklavenarbeit) und der Zukunft (freie Arbeit/Lohnarbeit) und als Spagat zwischen beiden Systemen. Sie wurde als ein Übergangsstadium und Teil eines versprochenen Wandels dargestellt. Die Teeplantagen Assams nahmen wie viele andere tropische Plantagen in Südasien auch im 19. Jahrhundert offiziell ihren Betrieb auf. Ursprünglich wurden sie von lokalen Arbeitern betrieben. Erst in den späten 1850er-Jahren wurden die lokalen Arbeiter durch von außerhalb der Provinz importierten Arbeitskräften ersetzt, die in der historischen Literatur gemeinhin unproblematisch mit dem Begriff "Coolies" belegt werden. Durch eine Analyse des Übergangs von der lokal rekrutiert für "Kuli" Arbeit und durch eine Analyse seiner Einführung die Studie argumentiert, dass "Kuli" Arbeit wurde "produziert" in den Kolonialkapitalistischen Plantagen in Assam. Mein Anliegen besteht dabei ausdrücklich nicht darin, einen zügellosen kolonialen Kapitalismus nahezulegen, dessen Strategie es ist, "Coolies" zu definieren und hervorzubringen oder die historischen Umstände, Verhandlungen, Streitfragen und Krisen zu betonen. Ich versuche vielmehr, die Erzählungen vom plötzlichen Auftauchen des archetypischen Teeplantagen-"Coolies" (d.i. als importierter und unfreier Lohnarbeiter) zu hinterfragen und sein Erscheinen, sein Bestehen und seine Verlagerungen mehr im Sinne grundlegender und diskursiver Prozesse auszulegen.“Coolie” is a generic category for the “unskilled” manual labour. The offering of services for hire had various pre-colonial lineages. In the nineteenth century there was an attempt to recast the term in discursive constructions and material practices for “mobilized-immobilized” labour. Coolie labour was often proclaimed as a deliberate compromise straddling the regimes of the past (slave labour) and the future (free labour). It was portrayed as a stage in a promised transition. The tea plantations of Assam, like many other tropical plantations in South Asia, were inaugurated and formalized during this period. They were initially worked by the locals. In the late 1850s, the locals were replaced by labourers imported from outside the province who were unquestioningly designated “coolies” in the historical literature. Qualifying this framework of transition (local to coolie labour) and introduction (of coolie labour), this study makes a case for the “production” of coolie labour in the history of the colonial-capitalist plantations in Assam. The intention of the research is not to suggest an unfettered agency of colonial-capitalism in defining and “producing” coolies, with an emphasis on the attendant contingencies, negotiations, contestations and crises. The study intervenes in the narratives of an abrupt appearance of the archetypical coolie of the tea gardens (i.e., imported and indentured) and situates this archetype’s emergence, sustenance and shifts in the context of material and discursive processes.
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Araujo, Alexandre Martins de. "Entre-jornadas: coolies e negros nas plantations de trinidad, 1845 – 1890." Universidade Federal de Goiás, 2007. http://repositorio.bc.ufg.br/tede/handle/tede/4667.
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This study is on the relationship between Indian and African Descendant Community in Trinidad during the nineteenth century. Theses two populations coexisted under the tense atmosphere involving all kinds of stereotypes, dispersion policies and interest wars from local gazettes playing in defense of each involved group. Thus arises the following question: how was it possible for the two groups to work together, that is, in the same space of plantation, without serious conflicts? A probable response to this question is found on perception of existence of cultural negotiation spaces, built up by circumstance of “liminal stage”, into the “journeys”, in which people from different cultures can temporally seeing each other without social status.
Este estudo discute o relacionamento entre as comunidades de Indianos e Afro-descendentes em Trinidad, durante o século dezenove. Essas duas populações coexistiram sob uma tensa atmosfera envolvendo todo o tipo de construção de estereótipos, políticas de dispersão e guerras de interesses por parte de jornais locais em defesa de cada grupo envolvido. Assim, surge a seguinte questão: como foi possível, para os dois grupos trabalharem juntos, quer dizer, no mesmo espaço das Plantations sem sérios conflitos? Uma provável resposta a esta questão é encontrada na percepção da existência de espaços culturais de negociação, construídos por meio de circunstâncias de “estágios liminares”, dentro de “jornadas”, nas quais pessoas de diferentes culturas podem, temporariamente, perceber um ao outro despojados de status social.
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Varma, Nitin [Verfasser], Michael [Akademischer Betreuer] Mann, and Ravi [Akademischer Betreuer] Ahuja. "Producing tea coolies? : Work, life and protest in the colonial tea plantations of Assam, 1830s- 1920s / Nitin Varma. Gutachter: Michael Mann ; Ravi Ahuja." Berlin : Humboldt Universität zu Berlin, Philosophische Fakultät III, 2013. http://d-nb.info/1046073907/34.
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Morrison, John William. "Auxiliary cooling in heat pipe cooled hypersonic wings." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/17113.
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Al-Neama, Ahmed Fouad Mahmood. "Serpentine minichannel liquid-cooled heat sinks for electronics cooling applications." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/20318/.
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The increasing density of transistors in electronic components is leading to an inexorable rise in the heat dissipation that must be achieved in order to preserve reliability and performance. Hence, improving the thermal management of electronic devices is a crucial goal for future generations of electronic systems. Therefore, a complementary experimental and numerical investigation of single-phase water flow and heat transfer characteristics of the benefits of employing three different configurations of serpentine minichannel heat sink (MCHS) designs has been performed, to assess their suitability for the thermal management of electronic devices. These heat sinks are termed single (SPSMs), double (DPSMs) and triple path serpentine rectangular minichannels (TPSMs), and their performance is compared, both experimentally and numerically, with that of a design based on an array of straight rectangular minichannels (SRMs) in terms of pressure drop (ΔP), average Nusselt number (Nuavg) and total thermal resistance (Rth). The results showed that the serpentine channel bends are very influential in improving heat transfer by preventing both the hydrodynamic and thermal boundary layers from attaining a fully-developed state. The SPSM design provides the most effective heat transfer, followed by the DPSM and TPSM ones, both of which out-performed the SRM heat sink. The SPSM heat sink produced a 35% enhancement in Nuavg and a 19% reduction in Rth at a volumetric flow rate (Qin) of 0.5 l/min compared to the conventional SRM heat sink. These improvements in the heat transfer are, however, achieved at the expense of significantly larger ΔP. It was found that the incorporation of serpentine minichannels into heat sinks will significantly increase the heat-removal ability, but this must be balanced with the pressure drop requirement. Therefore, an experimental and numerical investigation of the benefit of introducing chevron fins has been carried out to examine the potential of decreasing pressure drop along with further thermal enhancement. This novel design is found to significantly reduce both the ΔP across the heat sink and the Rth by up to 60% and 10%, respectively, and to enhance the Nuavg by 15%, compared with the SPSM heat sink without chevron fins. Consequently, the design of the SPSM with and without chevron fins was then optimised in terms of the minichannel width (Wch) number of minichannels (Nch) and chevron oblique angle (θ). The optimisation process uses a 30 (without chevron fins) and 50 (with chevron fins) point Optimal Latin Hypercubes Design of Experiment, generated from a permutation genetic algorithm, and accurate metamodels built using a Moving Least Square (MLS) method. A Pareto front is then constructed to enable the compromises available between designs with a low pressure drop and those with low thermal resistance to be explored and appropriate design parameters to be chosen. These techniques have then been used to explore the feasibility of using serpentine MCHS and heat spreaders to cool GaN HEMTs.
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Al-Maeeni, Lway. "Sub-cooled nucleate boiling flow cooling experiment in a small rectangular channel." Thesis, KTH, Fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-170396.
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Fu, Kang. "Experimental and analytic evaluation of gas-cooled reactor cavity cooling system performance." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13290.
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Kroger, Detlev G. "Air-cooled heat exchangers and cooling towers : thermal-flow performance evaluation and design." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49822.
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Thesis (PhD)--Stellenbosch University, 2004.ENGLISH ABSTRACT: During the last 30 years I have been involved in the theory and practice of thermal engineering and in particular, in the areas of air-cooled heat exchangers and cooling towers for the power, refrigeration, process and petrochemical industries in South Africa and internationally. During this period, I have authored and co-authored more than 120 papers that were published in technical journals or presented at conferences nationally or internationally. Most of these papers are included in a manuscript entitled "Air-cooled Heat Exchangers and Cooling Towers", in which Ipresent a systematic approach to the thermal performance evaluation and design of industrial air-cooled heat exchangers and cooling towers. This original publication also includes the relevant practice applicable to the design of cooling systems, based on my experience as a consultant to industry. Design offices throughout the world presently follow our design methods, or at least employ many of our research results. Our work has furthermore contributed to the development of improved cooling system designs (e.g. new dephlegmator header designs), components (e.g. single-row flattened finned tubes) and product improvement and quality control (e.g. performance testing and measurement of thermal contact resistance between fin and tube during production). Many of our research findings have found application in the modification of existing cooling systems. The manuscript has also been used as reference work during the presentation of short courses to practising engineers and consultants in industry and to engineering graduates at the University of Stellenbosch. A two-volume edition of this manuscript was published by PennWell Corp., Tulsa, Oklahoma, USA in 2004.
AFRIKAANSE OPSOMMING: Gedurende die laaste 30 jaar was ek betrokke by die teorie en praktyk van lugverkoelde warmteoordraers en koeltorings vir die kragopwekkings-, verkoelings-, proses- en petro-chemiesenywerhede in Suid-Afrika sowel as in die buiteland. Gedurende hierdie periode was ek outeur en mede-outeur van meer as 120 publikasies wat in tegniese tydskrifte, of by plaaslike of oorsese konferensies aangebied is. Die meeste van hierdie publikasies vorm deel van 'n manuskrip getiteld "Air-cooled Heat Exchangers and Cooling Towers" waarin ek 'n sistematiese benadering tot die bepaling van die termiese vermoë en ontwerp van industriële lugverkoelde warmteoordraers en koeltorings aanbied. Hierdie oorspronklike publikasie bevat ook die relevante praktyk wat van toepassing is op verkoelingsaanlegte. Ontwerpkantore wêreldwyd volg tans hierdie ontwerpsmetodes, of gebruik ten minste baie van ons navorsingsresultate. Ons werk het verder bygedra tot die ontwikkeling van verbeterde verkoelingsaanlegte (bv. nuwe deflegmatore), komponente (bv. enkelbuisry platvinbuise ) en verbeterde produkte en kwaliteitskontrole (bv. toetsing van verkoelingsvermoë oftermiese kontakweerstand tussen vin en buis gedurende produksie). Baie van ons bevindinge het toepassing gevind in die modifikasie van verkoelingsaanlegte. Die manuskrip is ook as verwysing gebruik gedurende die aanbieding van kort kursusse aan ingenieurs in die praktyk en aan nagraadse studente aan die Universiteit van Stellenbosch. 'n Twee-volume uitgawe van die manuskrip is deur PennWell Corp., Tulsa, Oklahome, VSA in 2004 gepubliseer.
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Griffiths, Philip Gavin, and phil@philgriffiths id au. "The making of White Australia: Ruling class agendas, 1876-1888." The Australian National University. Faculty of Arts, 2007. http://thesis.anu.edu.au./public/adt-ANU20080101.181655.
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This thesis argues that the colonial ruling class developed its first White Australia policy in 1888, creating most of the precedents for the federal legislation of 1901. White Australia was central to the making of the Australian working class, to the shaping of Australian nationalism, and the development of federal political institutions. It has long been understood as a product of labour movement mobilising, but this thesis rejects that approach, arguing that the labour movement lacked the power to impose such a fundamental national policy, and that the key decisions which led to White Australia were demonstrably not products of labour movement action.
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It finds three great ruling class agendas behind the decisions to exclude Chinese immigrants, and severely limit the use of indentured coloured labour. Chinese people were seen as a strategic threat to Anglo-Australian control of the continent, and this fear was sharpened in the mid-1880s when China was seen as a rising military power, and a necessary ally for Britain in its global rivalry with Russia. The second ruling class agenda was the building of a modern industrial economy, which might be threatened by industries resting on indentured labour in the north. The third agenda was the desire to construct an homogenous people, which was seen as necessary for containing social discontent and allowing free institutions, such as parliamentary democracy.
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These agendas, and the ruling class interests behind them, challenged other major ruling class interests and ideologies. The result was a series of dilemmas and conflicts within the ruling class, and the resolution of these moved the colonial governments towards the White Australia policy of 1901. The thesis therefore describes the conflict over the use of Pacific Islanders by pastoralists in Queensland, the campaign for indentured Indian labour by sugar planters and the radical strategy of submerging this into a campaign for North Queensland separation, and the strike and anti-Chinese campaign in opposition to the use of Chinese workers by the Australasian Steam Navigation Company in 1878. The first White Australia policy of 1888 was the outcome of three separate struggles by the majority of the Anglo-Australian ruling classto narrowly restrict the use of indentured labour in Queensland, to assert the right of the colonies to decide their collective immigration policies independently of Britain, and to force South Australia to accept the end of Chinese immigration into its Northern Territory. The dominant elements in the ruling class had already agreed that any serious move towards federation was to be conditional on the building of a white, predominantly British, population across the whole continent, and in 1888 they imposed that policy on their own societies and the British government.
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Kim, Taewhan. "Buffer gas cooling of ions in a radio frequency quadrupole ion guide, a study of the cooling process and cooled beam properties." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0021/NQ44656.pdf.
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Kim, Taeman. "Buffer gas cooling of ions in a radio frequency quadrupole ion guide : a study of the cooling process and cooled beam properties." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35666.
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The buffer gas cooling process and the properties of the cooled beam in a novel rf quadrupole ion beam guide with axial field was studied. The operation principle of the axial field quadrupole ion beam guide is similar to the quadrupole mass filter operating in AC only mode but the rods were segmented and differential DC biases were applied to produce the axial field. It was operated in buffer gas.A Monte Carlo simulation was developed and the simulation results were compared with the experimental results. The beam distribution in a thermal equilibrium was assumed as the thermal equilibrium distribution in a simple harmonic motion with rf distortion and the assumption was confirmed by the Monte Carlo simulation.
The temperature of the cooled beam was measured with a beam profile, measurement system which consists of a miniature quadrupole ion beam guide aid a rotating semi-circular Faraday plate. The temperature of the cooled beam was measured to be 0.0424 +/- 0.0026 eV in the experiment while that of the simulated beam was 0.0372 +/- 0.0009 eV. The variation of beam temperature with beam current was 0.0153 +/- 0.0026 eV/nA. The maximum achieved ion transmission was 80%. The transmitted ion beam's energy spread was measured with a retarding potential energy analyzer to be less than 0.1 eV. The cooling time was 0.7 ms with 1V/ cm axial field and was observed to be very dependent on the ion current when there was no axial field.
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Wei, Hong-Chan. "Reactor cavity cooling system heat removal analysis for a high temperature gas cooled reactor." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0024427.
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Ratts, Eric B. (Eric Bradley) 1963. "Cooling enhancement of forced convection air cooled chip array through active and passive flow modulation." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15072.
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Aljohani, Faraj Jaber R. "Improving Cooling Effectiveness in Air-Cooled Data Centres: Analysis and Assessment using Computational Fluid Dynamics." Thesis, Curtin University, 2018. http://hdl.handle.net/20.500.11937/75227.
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Datacentre efficiency becomes increasingly important as demand for IT infrastructure grows. This thesis presents detailed Computational Fluid Dynamics analyses of flow and heat transfer within typical raised floor datacentres. Compared with previous studies, greater understanding of the unsteady flow and heat transfer in datacentres resulted from using Scale-Adaptive turbulence modelling instead of a RANS approach. This led to a novel rack-level sub-cooler design, which was shown to allow higher volumetric heat generation rates within datacentres.
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Hausgen, Paul E. "An analysis of mono-dispersed liquid droplet cooling." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/16746.
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Delaney, Michael J. (Michael James) 1979. "Risk-informed design guidance for a Generation-IV gas-cooled fast reactor emergency core cooling system." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17747.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2004.Includes bibliographical references (p. 75-77).
Fundamental objectives of sustainability, economics, safety and reliability, and proliferation resistance, physical protection and stakeholder relations must be considered during the design of an advanced reactor. However, an advanced reactor's core damage frequency dominates all other considerations at the preliminary stage of reactor design. An iterative four-step methodology to guide the MIT gas-cooled fast reactor emergency core cooling system design through PRA insights was utilized based upon the preliminary stage of the reactor design and activities currently ongoing in the nuclear industry, regulator, and universities regarding advanced reactors. Advanced reactor designs also face an uncertain regulatory environment. It was concluded from the move towards risk- informed regulations of current reactors, that there will be some level of probabilistic insights in the regulations and supporting regulatory documents for advanced, "Generation-IV" nuclear reactors. The four-step methodology is moreover used to help designers analyze designs under potential risk-informed regulations and predict design justifications the regulator will require during the licensing process. The iterative design guidance methodology led to a reduction of the CDF contribution due to a LOCA of over three orders of magnitude from the baseline ECCS design (from 1.19x10-5 to 6.48x10-8 for the 3x100% loop configuration) and potential ECCS licensing issues were identified. This illustrates the value of formal design guidance based upon PRA.
by Michael J. Delaney.
S.M.
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Vacková, Tereza. "Chlazení ve vzduchotechnice." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-371992.
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This diploma thesis deals with the issue of regrigerant cooling. The theoretical part describes laws of termodynamics, basic thermodynamic processes of ideal gas and cooling cycles. The dependence of the cooler bypass factor of air handling unit on its capacity is the main issue of the experimental part. The aim of practical part is to design the air-conditioning device using knowledge of experimental part and compare it with the proposal of air-conditiong device in my bachelor thesis.
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Větrovec, Ondřej. "Návrh řešení chladiče elektrického komponentu automobilového světlometu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231796.
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This thesis is concerned with the cooling of electronic component. The work focuses on contemporary design of LED signal functions used in modern automotive headlamps and a on new design solution for the DRL function in the headlamp Skoda Octavia, including the use of alternative materials for cooler.
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Katta, Kiran Kumar. "Phase change cooling applications engine cooling /." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Giacomelli, Gene, and Kathryn Hahne. "Evaporative Cooling in Semi-Arid Climates." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008. http://hdl.handle.net/10150/146294.
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2 pp.In the semi-arid climate of southern AZ, evaporative cooling systems are commonly used and very effective for cooling homes (swamp coolers), outdoor areas (misters), and for greenhouses used for commercial and horticultural plant production (pad-and-fan, high-pressure-fog). The purpose of this brochure is to educate users about strategies they can employ to save water and improve the performance of evaporative cooling systems. Principles of operation, a list of advantages and disadvantages, and a comparison of common systems is also included, to help users decide the best system for them.
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Adams, Imani Noel. "Comprehensive Analysis of a Scaled-Down Low-Temperature Direct Reactor Auxiliary Cooling System for Fluoride Salt-Cooled High-Temperature Reactors." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366464705.
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Chen, Ruiping. "Laser cooling of atoms for ultracold cooling." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479242.
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Maciel, Alisson Ceccatto. "Viabilidade do sêmen equino armazenado em um sistema de polietileno para transporte por até oito horas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/108172.
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O objetivo deste estudo foi testar um sistema de Polietileno para o transporte de sêmen equino refrigerado por um período de até oito horas. Foram utilizados um total de 87 ejaculados de cinco diferentes garanhões, com idade média de 10 anos, sendo três da raça Puro Sangue de Corrida e dois da raça Pônei Miniatura Brasileiro. Os garanhões foram coletados duas vezes por semana utilizando vagina artificial. Após cada coleta, o sêmen foi avaliado a fresco e diluído na proporção 1+1 (diluente + sêmen) com leite desnatado UHT e dividido em quatro alíquotas de igual volume. No grupo controle (GC) o sêmen foi analisado logo após a diluição (zero hora – 0h). Nos demais grupos o sêmen foi mantido por oito horas (8h) em três diferentes sistemas de transporte: Equitainer® (GE), Botuflex®(GB) e Sistema de Polietileno - Refrigerado (SP) ou Não-Refrigerado (SPN). Foram avaliadas a motilidade total, vigor, a integridade de membrana plasmática (CFDA/PI), funcionalidade de membrana plasmática (HOST) e morfologia espermática. No SP não ocorreu diferença estatística em todos os parâmetros avaliados, quando comparado com o GE e o GB (médias da motilidade total = 45,00%, 49,29% e 46,40%; médias do vigor = 2,04, 2,18 e 2,01; médias do CFDA/PI = 71,12%, 73,29%, 71,32; médias do HOST = 39,70%, 41,21% e 39,76%; e médias da morfologia = 80,50%, 82,29% e 81,28%, valores respectivos de cada parâmetro para SP, GE e GB), enquanto o SPN apresentou valores médios inferiores ao GE para todos os parâmetros avaliados (médias da motilidade total = 50,65% e 62,60%; médias do vigor espermático = 1,78 e 2,43; médias do CFDA/PI = 72,56% e 78,30%; médias do HOST = 43,56% e 48,87%; médias da morfologia = 77,17% e 84,82%, respectivamente para SPN e GE). Com base nos dados podemos concluir que o SP foi igual ou não diferiu dos demais sistemas estudados, já o SPN se apresentou inferior aos demais sistemas estudados neste experimento. Portanto, o uso do SP é indicado para o transporte de sêmen refrigerado por oito horas, quando comparado aos demais sistemas estudados neste trabalho.The aim of this study was to test a polyethylene system to ship equine cooled semen. A total of 87 ejaculates from five different stallions with known fertility, mean age 10 years, were used, being three Thoroughbred and two Miniature Pony horse. The stallions were collected twice a week using an artificial vagina. After each collection the semen was diluted 1+1 (diluent+semen) with UHT skim milk and divided into four aliquots of equal volume, yielding a total of four groups. In the control group (CG) the semen was analyzed immediately after dilution (zero hour - 0h). In the other groups semen was stored for eight hours (8h) in three different transport systems: Equitainer® (EG), Botuflex® (BG) and Polyethylene System - Cooled (PS) or Non-Cooled (NPS). The total motility, vigor, plasma membrane integrity (CFDA/PI), plasma membrane functionality (HOST) and sperm morphology were evaluated. In PS did not occur a statistical difference in all parameters compared with EG and BG (averages of total motility = 45.00%, 49.29% and 46.40%, the average effect = 2.04, 2 18 and 2.01; averages CFDA / PI = 71.12%, 73.29%, 71.32; averages HOST = 39.70%, 41.21% and 39.76%, and the average of morphology = 80.50%, 82.29% and 81.28%, respective values of each parameter to PS, EG and BG), while the NPS showed lower mean values than the EG to all parameters (total motility averages = 50,65% and 62,60%, sperm vigor averages = 1,78 and 2,43; CFDA / PI averages = 72,56% and 78,30%; HOST averages = 43,56% and 48,87 %, morphology averages = 77.17% and 84.82%, respectively for NPS and EG). Based on the results we can conclude that the PS was equal or did not differ from the other systems studied, the NPS already performed lower than the other systems studied in this experiment. Therefore, the use of the SP is indicated for the transport of cooled semen for eight hours as compared to other systems studied in this work.
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Bastl, Ondřej. "Chladicí okruh pro formulový motor." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230484.
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Diploma thesis is focused on design engine cooling system for formula vehicle type. The aim is introduce with cooling systems of Formula Student/SAE car and competition rules. Based on the famous engine determine the initial conditions for the cooling system. In addition to design all parts of the cooling system and check affordability.
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Alsaiari, Abdulmohsen Omar. "Augmentation of Jet Impingement Heat Transfer on a Grooved Surface Under Wet and Dry Conditions." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/98502.
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Array jet impingement cooling experiments were performed on flat and grooved surfaces with the surface at a constant temperature. For the flat surface, power and temperature measurements were performed to obtain convection coefficients under a wide range of operating conditions such as jet speed, orifice to surface stand-of distance, and open area percentage. Cooling performance (CP) was calculated as the ratio between heat transfer and fan power. An empirical model was developed to predict jet impingement heat transfer taking into account the entrainment effects. Experimental results showed that jet impingement can provide high transfer rates with lower rates of cooling cost in comparison to contemporary conventional techniques in the industry. CP values over 279 were measured which are significantly higher than the standard values of 70 to 95 in current technology. The model enhanced prediction accuracy by taking into account the entrainment effects; an effect that is rarely considered in the literature. Experiments on the grooved surfaces were performed at dry and wet surface conditions. Under dry conditions, results showed 10%~55% improvement in heat transfer when compared to the flat surface. Improvement percentage tends to be higher at wider gaps between the array of orifices and the grooved surface. An improvement of 30%~40% was observed when increasing Re either by increasing orifice diameter or jet speed. Similar improvement was observed at higher flow open area percentages. No significant improvement in heat transfer resulted from decreasing the size of the grooves from 3.56mm to 2.54mm. Similarly, no noticeable change in heat transfer resulted from changing the relative position of the jets striking the surface at the top of the grooves to the bottom of the grooves. Deeper grooves with twice the depth gave statistically similar average heat transfer coefficients as shallower grooves. Under wet conditions, a hybrid cooling technique approach was proposed by using air jets impinging on a grooved surface with the grooves containing water. The approached is proposed and evaluated experimentally for its feasibility as an alternative for cooling towers of thermoelectric power plants. Convection heat and mass transfer coefficients were measured experimentally using the heat mass transfer analogy. Results showed that hybrid jet impingement provided high magnitudes of heat flux at low jet speeds and flow rates. High coefficients of performance CP > 3000, and heat fluxes > 8,000W/m2 were observed. Hybrid jet impingement showed 500% improvement as compared to jet impingement on a dry flat surface. CP values of hybrid jet impingement is 600% to 1,500% more as compared to performance of air-cooled condensers and wet cooling towers. Water use for hybrid jet impingement cooling is efficient since evaporation energy is absorbed from the surface directly instead of cooling air to near wet-bulb temperature.PHD
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Graça, Guilherme Carrilho da 1972. "Ventilative cooling." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/66785.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 1999.Includes bibliographical references (p. 131-134).
This thesis evaluates the performance of daytime and nighttime passive ventilation cooling strategies for Beijing, Shanghai and Tokyo. A new simulation method for cross-ventilated wind driven airflow is presented . This method decouples the airflow model from the thermal model allowing for fast real weather simulation of the building thermal performance. The simulation is performed on a six-story, isolated, suburban apartment building, considered to be typical of the three cities. The performance of the two natural ventilation strategies on this building is compared . The impact on the performance of different types of construction is assessed for the night cooling ventilation strategy. The results show that night cooling is superior to daytime ventilative cooling in the three cities. Night cooling can successfully replace air conditioning systems for a significant part of the cooling season in Beijing and Tokyo. For Shanghai, neither of the two passive ventilation systems can be considered successful. In both Beijing and Tokyo the application of night cooling may cause condensation in partitions. The use of heavyweight partitions does not show a noticeable improvement over normal construction (using 10cm concrete partitions) . On the other hand, the lightweight case shows a noticeable degradation in system performance. Therefore, the normal structural system is the best option. The use of carpet has a very negative impact on night cooling performance, and is therefore not advised.
by Guilherme Carrilho da Graça.
S.M.
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Rizvani, Lejla. "Cooling Oasis." Thesis, KTH, Arkitektur, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298809.
Full textAbstract:
The urban heat island, UHI, is a phenomenon that occurs in all cities. This phenomenon is an effect of us humans and the environments we have built. What happens in cities are that they re-emit the suns heat and other energies trapping them in this heat island. The re-emitting happens through the pavement of the city, lack of greenery, roads and how the city is built and its geometry. Cities with skycrapers and of high density see a greater impact of the urban heat island where the wind flow is reduced and more heat is trapped and stored. The UHI is worst experienced in places with a very hot climate, such as the arid desert climate with extreme temperatures year round, like in the UAE and Dubai. It is vital to tackle the UHI effect problem, because it puts people at danger. Many lives are shed each year due to heat strokes, that can be reduced if we take this problem into consideration when we design our cities. The UHI effect can be reduced by simple yet effective steps.
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Podadera, Aliseda Ivan. "New developments on preparation of cooled and bunched radioactive ion beams at ISOL-Facilities: the ISCOOL project and the rotating wall cooling." Doctoral thesis, Universitat Politècnica de Catalunya, 2006. http://hdl.handle.net/10803/6619.
Full textAbstract:
Last years have become very productive for the research, construction and development of new facilities devoted to the production of beams with exotic radioisotopes (Radioactive Ion Beams, RIB). These beams are later used for experiments in fields like nuclear physics, atomic physics, astrophysics or medicine, among others. Within this kind of facilities, the ISOL facilities stand out. They are based on the on-line separation of radioactive isotopes produced in nuclear reactions between a target and a high-energy proton beam. The ISOL method was the pioneer for these facilities and it has kept up to now the leadership of RIB facilities. The main reason is ISOLDE, an ISOL facility located at CERN, the largest accelerator complex in the world, where this doctoral thesis has been carried out.The first innovation which is described is the design of an ion trap for the cooling and bunching of RIB's for ISOLDE, the so-called ISCOOL (ISOLDE COOLer). It is an Radio Frequency Quadrupole ion Cooler and Buncher (RFQCB), device based on the Paul traps. In these traps, the ions are confined in the three dimensions by electric fields. The ions are confined on the transverse plane with the pseudopotential well created by the Radio Frequency Quadrupole (RFQ) and focused on the longitudinal axis. At the same time, a gas (normally helium) fills the chamber with a pressure between 10-3 and 10-2 mbar. The collisions between the atoms or molecules of the gas and the ions. In addition, to drive the ions to the extraction of the RFQCB, an axial electric field is created by segmented electrodes. Different voltages are applied to these electrodes in order to choose the shape of the field. The shape can be chosen to create a potential well close to the extraction from the RFQCB in which the ions are accumulated and extracted as bunches, by the fast-switch of the voltages applied to the axial electrodes.
The new ISCOOL will be installed as a permanent device of the ISOLDE beam lines.
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Redmond, Matthew J. "Thermal management of 3-D stacked chips using thermoelectric and microfluidic devices." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50240.
Full textAbstract:
This thesis employs computational and experimental methods to explore hotspot cooling and high heat flux removal from a 3-D stacked chip using thermoelectric and microfluidic devices. Stacked chips are expected to improve microelectronics performance, but present severe thermal management challenges. The thesis provides an assessment of both thermoelectric and microfluidic technologies and provides guidance for their implementation in the 3-D stacked chips.
A detailed 3-D thermal model of a stacked electronic package with two dies and four ultrathin integrated TECs is developed to investigate the efficacy of TECs in hotspot cooling for 3-D technology. The numerical analysis suggests that TECs can be used for on demand cooling of hotspots in 3-D stacked chip architecture. A strong vertical coupling is observed between the top and bottom TECs and it is found that the bottom TECs can detrimentally heat the top hotspots. As a result, TECs need to be carefully placed inside the package to avoid such undesired heating. Thermal contact resistances between dies, inside the TEC module, and between the TEC and heat spreader are shown to significantly affect TEC performance.
TECs are most effective for cooling localized hotspots, but microchannels are advantageous for cooling large background heat fluxes. In the present work, the results of heat transfer and pressure drop experiments in the microchannels with water as the working fluid are presented and compared to the previous microchannel experiments and CFD simulations. Heat removal rates of greater than 100 W/cm2 are demonstrated with these microchannels, with a pressure drop of 75 kPa or less. A novel empirical correlation modeling method is proposed, which uses finite element modeling to model conduction in the channel walls and substrate, coupled with an empirical correlation to determine the convection coefficient. This empirical correlation modeling method is compared to resistor network and CFD modeling. The proposed modeling method produced more accurate results than resistor network modeling, while solving 60% faster than a conjugate heat transfer model using CFD.
The results of this work demonstrate that microchannels have the ability to remove high heat fluxes from microelectronic packages using water as a working fluid. Additionally, TECs can locally cool hotspots, but must be carefully placed to avoid undesired heating. Future work should focus on overcoming practical challenges including fabrication, cost, and reliability which are preventing these technologies from being fully leveraged.
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Fletcher, Daniel Alden. "Internal cooling of turbine blades : the matrix cooling method." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360259.
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VILAFRANCA, MANGUÁN ANA. "Convesion of industrial compression cooling to absorption cooling in an integrated district heating and cooling system." Thesis, University of Gävle, University of Gävle, Department of Technology and Built Environment, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-4145.
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Astra Zeneca plant in Gärtuna has many compression cooling machines for comfort that consume about 11.7 GWh of electricity per year. Many of the cooling machines are old; due to the increase of production of the plant, cooling capacity was limited and new machines have been built. Now, the cooling capacity is over-sized. Söderenergi is the district heating plant that supplies heating to Astra Zeneca plant. Due to the strict environmental policy in the energy plant, last year, a bio-fuelled CHP plant was built. It is awarded with the electricity certificate system.
The study investigates the possibility for converting some of the compression cooling to absorption cooling and then analyzes the effects of the district heating system through MODEST optimizations. The effects of the analysis are studied in a system composed by the district heating system in Södertälje and cooling system in Astra Zeneca. In the current system the district heating production is from boiler and compression system supplies cooling to Astra Zeneca. The future system includes a CHP plant for the heating production, and compression system is converted to absorption system in Astra Zeneca. Four effects are analyzed in the system: optimal distribution of the district heating production with the plants available, saving fuel, environmental impact and total cost. The environmental impact has been analyzed considering the marginal electricity from coal condensing plants. The total cost is divided in two parts: production cost, in which district heating cost, purchase of electricity and Emissions Trading cost are included, and investment costs. The progressive changes are introduced in the system as four different scenarios.
The introduction of the absorption machines in the system with the current district heating production increases the total cost due to the low electricity price in Sweden. The introduction of the CHP plant in the district heating production supposes a profit of the production cost with compression system due to the high income of the electricity produced that is sold to the grid; it profit increases when compression is replaced by absorption system. The fuel used in the production of the future system decreases and also the emissions. Then, the future system becomes an opportunity from an environmental and economical point of view. At higher purchase electricity prices predicted in the open electricity market for an immediately future, the future system will become more economically advantageous.
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Sivagurunathan, Shivani. "Coolie cartography : crossing frontiers through coolitude." Thesis, University of Warwick, 2007. http://wrap.warwick.ac.uk/1161/.
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Following the abolition of Transatlantic slavery, the British introduced a new scheme of labour to replace the former. 'Indian indentureship', as it was referred to, affected nearly 2 million Indian coolies who defied the traditional ban against crossing the kala pani (dark waters) in order to work on plantations in countries such as British Guiana, Trinidad, Malaya, South Africa and Fiji. In effect, the Indian labour: diaspora emerged and established itself across the globe. Despite over 100 years of labouring and contributing to the development of their new homes, the coolies and their descendents still face political, social and cultural marginalization. The aim of this thesis is to explore the consequences of indentureship in various societies through a parallelization of inter-national coolie conditions as represented by writers of the diaspora. The three areas selected for this study are Guyana, Malaysia and Fiji. David Dabydeen (Guyana), K.S.Maniam (Malaysia) and Satendra Nandan (Fiji) all share the impetus to disclose the past as a portal into the present, thereby dismpting normative time, and by implication, a fixed sense of history. However; the most striking similarity between these writers, despite their geographical and social distance, is their literary method which centres on the theory of coolitude. Coolitude was coined by Khal Torabully as a means of recuperating the voiceless coolie, firstly, by re-membering the sea voyage across the kizla pani and secondly, by highlighting the coolie's place in the mosaic of multicultural societies. Chapter 1 details the historical, theoretical and methodical foundations of the thesis. Chapter 2 explores Dabydeen's novels The Counting House and Our Lady of Demerara while Chapter 3 is a detailed study of Maniam's novels The Return and In A Far Country. The final chapter considers Nandan's novel The Wounded Sea and collection of poetry Lines Across Black Waters. Each literary analysis seeks to understand how coolitude, as a means to historically and politically place the coolie in the current world,: links spaces between countries both through a shared colonial history and a common postcolonial condition.
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Guy, Ashley Ray. "Effect of Blowing Ratio on the Nusselt Number and Film Cooling Effectiveness Distributions of a Showerhead Film Cooled Blade in a Transonic Cascade." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/43764.
Full textAbstract:
This paper investigates the effect of blowing ratio on the film cooling performance of a showerhead film cooled first stage turbine blade. The blade was instrumented with double-sided thin film heat flux gages to experimentally characterize the Nusselt number and film cooling effectiveness distributions over the surface of the blade. The blade was arranged in a two-dimensional, linear cascade within a transonic, blowdown type wind tunnel. The wind tunnel freestream conditions were varied over two exit Mach numbers, Me=0.78 and Me=1.01, with an inlet freestream turbulence intensity of 12% , with an integral length scale normalized by blade chord of 0.26 generated by a passive, mesh turbulence grid. The coolant conditions were varied by changing the ratio of coolant to freestream mass flux, blowing ratio, over three values, BR=0.60, 1.0, and 1.5 while keeping a density ratio of 1.7.
Experimental results show that ingestion of freestream flow into the showerhead cooling plenum can occur below a blowing ratio of 0.6. Film cooling increases Nusselt number over the uncooled case and increasing the blowing ratio also increases Nusselt number. At a blowing ratio of 1.5 and Me=1.01 a large drop in effectiveness just downstream of injection on both the pressure and suction surfaces is evidence of jet liftoff. The blowing ratio of 1.0 was found to have superior heat load reduction over the blade surface at both freestream conditions tested. The blowing ratio of 1.0 reduced the heat load by as much as 39% and 32% at Me=0.78 and 1.01, respectively.Master of Science
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Ozmen, Emin Mehmet. "Part Cooling Analysis By Conformal Cooling Channels In Injection Molding." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12609186/index.pdf.
Full textAbstract:
Straight cooling channels are the most common method of controlling part temperature in
injection molding process. However, straight cooling channels are not enough to manage
temperature uniformity of the parts. In this work, a numerical study is conducted to decrease
cycle time and cost of the injection molded parts by using conformal cooling channels. For this
purpose, the commercial injection molding simulation program Moldflow is used.
The governing physical equations for injection molding were derived and presented. The
assumptions of the model were checked for simple geometries by comparing analytical results
and numerical results of Moldflow. Then, the effect of conformal cooling channels is
investigated for injection molding of a half cylinder shell part. It was seen that conformal cooling
channels cools part faster and more uniform than straight cooling channels without corruption on
the surface appearance.
Finally, a real life case study was presented. For this purpose, a refrigerator shelf that is
manufactured by the Arçelik Company was studied. The process was simulated using actual process parameters and simulation results were compared with production results. Then, the process was simulated using conformal cooling channels and compared with production results. It is seen that the cycle time of the refrigerator shelf was decreased considerably while preserving surface quality appearance.
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Omma, Henrik Nilsen. "Jet-powered cooling cores : reversing cooling flows through AGN activity." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419330.
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Aghasi, Paul P. "Dependence of Film Cooling Effectiveness on 3D Printed Cooling Holes." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458893416.
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Owen, Michael Trevor Foxwell. "A numerical investigation of air-cooled steam condenser performance under windy conditions." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4101.
Full textAbstract:
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: This study is aimed at the development of an efficient and reliable method of evaluating the performance of an air-cooled steam condenser (ACSC) under windy conditions, using computational fluid dynamics (CFD). A two-step modelling approach is employed as a result of computational limitations. The numerical ACSC model developed in this study makes use of the pressure jump fan model, amongst other approximations, in an attempt to minimize the computational expense of the performance evaluation. The accuracy of the numerical model is verified through a comparison of the numerical results to test data collected during full scale tests carried out on an operational ACSC. Good correlation is achieved between the numerical results and test data. Further verification is carried out through a comparison to previous numerical work. Satisfactory convergence is achieved for the most part and the few discrepancies in the results are explained. The effect of wind on ACSC performance at El Dorado Power Plant (Nevada, USA) is investigated and it is found that reduced fan performance due to distorted flow at the inlet of the upstream fans is the primary contributor to the reduction in performance associated with increased wind speed in this case. An attempt is subsequently made to identify effective wind effect mitigation measures. To this end the effects of wind screens, solid walkways and increasing the fan power are investigated. It is found that the installation of an appropriate wind screen configuration provides a useful means of reducing the negative effects of wind on ACSC performance and an improved wind screen configuration is suggested for El Dorado. Solid walkways are also shown to be beneficial to ACSC performance under windy conditions. It is further found that ACSC performance increases with walkway width but that the installation of excessively wide walkways is not justifiable. Finally, increasing the fan power during periods of unfavourable ambient conditions is shown to have limited benefit in this case. The model developed in this study has the potential to allow for the evaluation of large ACSC installations and provides a reliable platform from which further investigations into improving ACSC performance under windy conditions can be carried out.
AFRIKAANSE OPSOMMING: Hierdie studie is daarop gemik om die ontwikkeling van 'n geskikte en betroubare metode van evaluering van die verrigting van ’n lugverkoelde stoom-kondensator (air-cooled steam condenser, ACSC) onder winderige toestande, met behulp van numeriese vloei-dinamika. ’n Twee-stap modelleringsbenadering is aangewend as gevolg van rekenaar beperkings. Die numeriese ACSC-model wat in hierdie studie ontwikkel is, maak gebruik van die druksprong waaier model, asook ander benaderings, in ’n poging om die berekeningskoste van die verrigting-evaluering te verminder. Die akkuraatheid van die numeriese model is bevestig deur middel van ’n vergelyking van die numeriese resultate met toetsdata ingesamel tydens die volskaal toetse uitgevoer op ’n operasionele ACSC. Goeie korrelasie is bereik tussen die numeriese resultate en toetsdata. Verdere bevestiging is uitgevoer deur middel van ’n vergelyking met vorige numeriese werk. Bevredigende konvergensie is in die algemeen bereik en die paar verskille in die resultate word verduidelik. Die effek van wind op ACSC verrigting by El Dorado Power Plant (Nevada, VSA) is ondersoek, en daar is bevind dat verlaagde waaierverrigting, as gevolg van vervormde vloei by die inlaat van die stroomop waaiers, die primêre bydraer is tot die afname in ACSC werkverrigting geassosieer met verhoogde windsnelheid in hierdie geval. ’n Poging word dan aangewend om effektiewe wind-effek velagingsmaatreëls te identifiseer. Windskerms, soliede wandelvlakke en die verhoging van die waaierkrag word gevolglik ondersoek. Daar is bevind dat die installasie van ’n toepaslike windskerm-opset ’n nuttige middel tot ’n vermindering van die negatiewe effekte van wind op ACSC verrigting bied, en ’n verbeterde windskerm opset is voorgestel vir El Dorado. Soliede wandelvlakke word ook aanbeveel as voordelig vir ACSC verrigting onder winderige toestande. Dit is verder bevind dat die ACSC prestasie verhoog met wandelvlak breedte, maar dat die installasie van ’n te ruim wandelvlak nie regverdigbaar is nie. Ten slotte, word bewys dat die verhoging van die waaierkrag tydens periodes van ongunstige omgewingsomstandighede ’n beperkte voordeel in hierdie geval het. Die model wat ontwikkel is in hierdie studie het die potensiaal om voorsiening te maak vir die evaluering van groot ACSC- installasies en bied ’n betroubare platform vanwaar verdere ondersoeke tot die verbetering van ACSC verrigting onder winderige toestande uitgevoer kan word.
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Ondrejka, Filip. "Nekonvenční chladicí systémy pro Formuli Student." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-444964.
Full textAbstract:
This master’s thesis deals with the design and manufacture of a heat exchanger with polymeric hollow fibers for a Formula Student vehicle. The work can be divided into three parts. The first part contains a review of heat transfer and heat exchangers, the second part deals with polymeric fiber heat exchangers design and manufacture of of polymeric hollow fibers heat exchanger with a heat exchanger for a Formula Student vehicle. The last part deals with the comparison of polymeric hollow fibers heat exchanger with the original aluminum heat exchanger and the evaluation of the measurement results.
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Manasrah, Ahmad. "Application and Analysis of Asymmetrical Hot and Cold Stimuli." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6309.
Full textAbstract:
The human body has a unique mechanism for perceiving surrounding temperatures. When an object is in contact with the skin, we do not feel its temperature. Instead, we feel the temperature change that is caused on our skin by that object. The faster the heat is transferred, the more intense the thermal sensation is. In this dissertation, a new dynamic thermal display method, where different rates of warm and cold are applied on the skin to generate a unique sensation, is presented. The new method can be related in a wide range of applications including thermal haptics and virtual reality.
To understand the perception of temperature and the general thermal state of the human body, the first aspect of this dissertation focuses on investigating the interaction between temperature change and perception on a large scale. Three field surveys were conducted inside airconditioned buildings to investigate the change in the thermal state and temperature perception of occupants when the room temperature changes. The results showed that the participants’ prediction of constant operating temperature was poor, however, their prediction was significantly improved when temperature changes were presented.
In order to more accurately investigate the perception of temperature on the skin, a new thermal display method using multiple-channel thermal actuators was developed. The principle of this method is to apply slow and fast rates of temperature change simultaneously on the skin. The slowly changing temperatures are below the perceptual threshold of the thermal receptors, therefore will not be detected whereas the quickly changing temperatures are above the perceptual threshold, hence, will be detected. The idea here is to keep the average surface temperature of the skin constant, however a person will perceive a sensation of continuous cooling. This method was tested through a series of experiments, and the results showed that it is capable of generating a continuous cooling sensation without changing the average temperature of the stimulation area. Multiple variations of this method were tested including different heating and cooling rates of change, different skin locations and patterns of stimuli. Also, a continuous warming was generated using similar concept.
To further investigate the temperature distribution that is caused by this method and its effect on the skin, a computational simulation was conducted. An approximate model of the skin was used to monitor its surface temperature and record the temperatures in the stimulation area when the continuous cooling method is applied. The results of the simulation showed that the temperature under the surface of the stimulation area was affected by the continuous cooling method that was applied on the skin model, however this method did not affect the average surface temperature of the skin. These findings may later determine the efficiency and intensity of the method of continuous cooling, and allow us to investigate different technically challenging variations of this method.
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Chan, Ying-kit. "Strange star cooling." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B3138254X.
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Chan, Ying-kit, and 陳英傑. "Strange star cooling." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B3138254X.
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Collins, Matthew C. J. "Casing effusion cooling." Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:8a7204f5-9436-4c11-b6d6-25aef0bff8f7.
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The design, modelling and testing of a film cooling system intended for the casing of an unshrouded HP turbine rotor is described in this thesis. Due to the dense network of small film cooling holes employed in such a system, this is often referred to as a casing effusion cooling scheme. Though there are patent references to such systems, there is as yet very limited published material on the aero thermal performance of such film cooling schemes. The casing of an unshrouded HP rotor is an incredibly hostile environment, witnessing the periodic passing of the HP rotor tips within close proximity at a frequency of ∼10 kHz. These blade passing events subject the casing to extremely large amplitude fluctuations of pressure and heat load, which may at first seem to preclude the use of a film cooling scheme. This thesis details many theoretical, computational and experimental advancements related to the research topic. Highlights include: The introduction of a new fundamental mechanism to the field of film cooling, the propagation and reflection of pressure waves within film cooling holes and the impact on film cooling performance. The development of new miniature thin film heat flux gauges manufactured using a new process. Sensor resolution is improved by a factor of seven. The first published computational model reporting heat transfer data on a film cooled rotor casing. Improvements to heat transfer data processing techniques and theory. These are applied to experimental work to produce the highest resolution heat transfer data obtained on the casing of a scaled rotating transonic HP rotor for both uncooled and cooled geometries. Computational models are used to demonstrate that coolant injection on the rotor casing reduces the over-tip leakage mass flow, offsetting the spoiling and mixing losses that film cooling schemes introduce. Much of the work in this thesis is based on papers that have been submitted to or are pending submission. To date three papers have been presented at conference with two published in journals and the third recommended and pending journal publication. Two other papers are pending submission. A patent has also been filed with the European and American patent office regarding novel film cooling hole shapes designed to make use of acoustic effects.
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Fernandes, Rita. "Efficient Volvo Bus Cooling System,Using Electrical Fans : A comparison between hydraulic and electrical fans." Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-155901.
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Economical and environmental factors together with energy policies towards more efficient systemsare the driving force for the development of the vehicle industry. Significant changes have beenmade to fulfill new emissions legislation but the basic internal combustion vehicle architecture hasbeen kept. New emission treatment systems that increase the thermal loading of the cooling systemhad been added within the same package envelope as before, which means less space to place coolingfans and a greater need for airflow. Changes in the cooling system, namely the replacement of thehydraulic fan drive system by electrical fans is one of the energy efficient alternatives for severalcity buses under certain environments, like the ”typical red city buses”, well-known in the UnitedKingdom. In this thesis study, hydraulic fans are compared with electrical fans and a road-mapof the benefits and drawbacks of the two systems is developed, based on real traffic performanceperformance data and the results of existing simulations and tests. In addition, new simulations arepresented in order to find the most efficient design for the cooling system as well as a comparisonof these results with previous ones. This road map will be used later by Volvo-Buses Group as atool to better understand in which circumstances electrical fans can be beneficial, in terms of fuelconsumption, noise production, cooling performance, control of the fans and associated costs.
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Greifenstein, Max [Verfasser], Andreas [Akademischer Betreuer] Dreizler, and Simone [Akademischer Betreuer] Hochgreb. "Experimental investigations of flame-cooling air interaction in an effusion cooled pressurized single sector model gas turbine combustor / Max Greifenstein ; Andreas Dreizler, Simone Hochgreb." Darmstadt : Universitäts- und Landesbibliothek, 2021. http://d-nb.info/1237816939/34.
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Ryjkov, Vladimir Leonidovich. "Laser cooling and sympathetic cooling in a linear quadrupole rf trap." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1637.
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An investigation of the sympathetic cooling
method for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap. The dependence of
rf heating rates on the ion temperature, trapping parameters,
and the number of ions is obtained. New rf heating mechanism
affecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra
of the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of
the laser cooled Mg$^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and
the influence of the rf heating rates on the fluorescence lineshapes
is also discussed. Cooling of the heavy ($m=720$a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg$^+$ ions($m=24$a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg$^+$ ion crystal structures at mK temperatures.
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Birkne, Oskar, and Jana Hanke. "Cooling a Bottle of Champagne: Mathematical Models for the Cooling Process." Thesis, KTH, Teoretisk fysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103462.
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Yang, Yifan. "Personal-portable Cooling Garment Based on Adsorption Vacuum Membrane Evaporative Cooling." Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19835.
Full textAbstract:
A cutting edge man-portable AVMEC cooling garment was demonstrated to be able to provide sufficient cooling for personnel working at mediate activity loads. Studies were first carried out in a well controlled vacuum desiccator at room temperature to elucidate the effects of several key parameters on the performance of an AVEC device, which was similar to AVMEC except that membrane was not involved. Under the best condition, an average cooling capacity of 179 W/M2 was achieved in a period of four hours and cooling continued at a slowly declining rate for another four hours afterward. The temperature of water was maintained at approximately 12.5 oC after the pseudo steady state was established. Then, it was shown that the AVMEC cooling pads were able to provide a cooling capacity of 277.4 W/m2 in a 37 oC ambient environment (incubator). The temperature of the cooling core surface was maintained in a range of 20 – 21.8 oC in the one-hour test period. No power supply was required except for the initialization stage, which took 5 minutes. Furthermore, human subject tests with or without wearing NWBC (Nuclear Warfare Biological and Chemical) suit demonstrated that, a AVMEC garment composed of 12 cooling pads were able to maintain the core body temperature of the subjects below 38.5 oC for up to 90 minutes while the subject was walking on a treadmill at a speed of 2 miles per hour in an environment of 40 oC and 50% RH (relative humidity). These results indicate that the AVMEC garment is a promising man-portable personal cooling technology.
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Chambers, Andrew. "An investigation of impingement cooling applied to turbine blade cooling passages." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400071.
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Balvin, Garcia Suley Virginia, Ruiz Erwin Jhonnatan Otarola, Flórez Karla Vanessa Ramírez, and Lozano Lilian Isela Seminario. "FRESH COOLER." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/653179.
Full textAbstract:
Hoy en día las tendencias por lo saludable están en ascenso, las circunstancias de salubridad mundial nos exigen pensar más en el bienestar propio y en las costumbres alimenticias a adoptar para reducir situaciones médicas de riesgo, es necesario adoptar una cultura de comidas saludables buscando soluciones que nos faciliten llevar a cabo actividades relacionadas a ella.
El presente trabajo de investigación está basado en la elaboración de contenedores con filtros de etileno, los cuales preservan por más tiempo los alimentos perecibles (frutas y verduras); buscamos replicar y traer al mercado doméstico una experiencia real aplicada hoy en la exportación de estos productos alrededor del mundo; basados en la investigación de mercado del proyecto evidenciamos que nuestro producto facilita el almacenamiento y la conservación de dichos alimentos. Este proyecto muestra las bondades del Filtro de Etileno que alarga la vida de alimentos perecibles a través de un compuesto químico llamado Permanganato de Potasio que, gracias a su propiedad antibacterial y aplicación aprobada para alimentos, elimina las bacterias que producen la oxidación de frutas. En estos momentos donde salir de casa o comprar con frecuencia representa un riesgo para la salud consideramos que nuestro producto solucionará este problema y reducirá considerablemente las perdidas por descomposición.
La empresa venderá los productos a través del canal retail, para llegar a más familias peruanas, el precio varía según el tamaño, pequeño S/22.00, mediano: S/29.00 y grande S/39.00.
Los filtros de Etileno se importarán de Italia y los envases de vidrio de China.Today the trends for healthy are on the rise, the circumstances of global health require us to think more about our well-being and the eating habits to adopt to reduce risky medical situations, it is necessary to adopt a culture of healthy meals looking for solutions that facilitate us to carry out activities related to it. The present research work is based on the elaboration of containers with ethylene filters, which preserve perishable foods (fruits and vegetables) for a longer time; We seek to replicate and bring to the domestic market a real experience applied today in the export of these products around the world; Based on the project's market research, we show that our product facilitates the storage and preservation of these foods. This project shows the benefits of the Ethylene Filter that lengthens the life of perishable foods through a chemical compound called Potassium Permanganate that, thanks to its antibacterial property and approved application for food, eliminates bacteria that cause oxidation of fruits. At these times were leaving home or shopping frequently represents a health risk, we believe that our product will solve this problem and considerably reduce losses due to decomposition. The company will sell the products through the retail channel, to reach more Peruvian families, the price varies according to size, small S / 22.00, medium: S / 29.00 and large S / 39.00. Ethylene filters will be imported from Italy and glass containers from China.
Trabajo de investigación
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Johansson, Eric. "Optimization of Ground Source Cooling Combined with Free Cooling for Protected Sites." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98657.
Full textAbstract:
Ground source cooling is commonly used for cooling of electronics in protected sites. Sometimes the boreholes are combined with free cooling from the air using a dry cooler to reduce the amount and length of the boreholes, which is the biggest part of the costs. The dry cooler can have two different running modes. In unloading mode the dry cooler is started at a certain temperature and the fans are slowed down at low temperatures so that the cooling power never exceeds the cooling demand. The extracted cooling is used to unload the boreholes. In recharging mode the dry cooler is started at a certain temperature and is operating at full capacity below this temperature. The excess cooling that is extracted in this mode is used to recharge the boreholes. The numerical simulation tool COMSOL Multiphysics was used to evaluate the borehole performance. The software can simulate tilted boreholes with good accuracy and makes it possible to adjust the geometry in any desired way. In this thesis, the performance of a 100 kW ground source cooling system is evaluated for a number of cases both with and without dry coolers in different running modes and sizes. The best solution in respect to life cycle cost, technical feasibility and environmental impact is chosen to be an unloading case with a dry cooler with 100 kW capacity at 8 °C. Using only boreholes gives less carbon dioxide emissions but much higher costs.