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Tesi sul tema "Circulation"
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1
Burkell, James J. "Solids circulation rate measurement in a circulating fluidized bed". Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26217.
Testo completoAbstract (sommario):
This thesis documents the investigation of three methods of determining solids fluxes in a circulating fluidized bed (CFB). An impact flowmeter used the force of the recirculating particles striking a pan which spanned the diameter of the return column to measure solids circulation rates. A modified orifice, with a conical entrance section, used the additional pressure differential resulting from solids flowing counter-currently to gas to determine solids fluxes. The third method used the velocities of particles travelling through the vertical section of an L-valve to determine solids circulation rates.
The results obtained in this work show that the impact flowmeter and the method utilizing L-valve particle velocities are viable methods of measuring solids fluxes in a CFB. However, further research is required before these methods can be confidently used. The modified orifice, as studied, was not sensitive enough to sense solids circulation. However, the meter may offer potential if studied with co-current gas solids flow.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
2
Schubert, Bastian. "Circulation Structured". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/36173.
Testo completoAbstract (sommario):
Circulation is the way by which people move and interact with a piece of architecture. In public buildings, such as transportation terminals, it is crucial to have a floor plan that allows easy flow of pedestrian traffic. Effective circulation in public areas such as these ensures a visitor can navigate conveniently and efficiently. Also, using circulation elements such as elevators, escalators, and staircases, optimizes the flow of individuals through a building while providing visual appeal as they can be positioned and designed creatively
Within my thesis I am investigating the relation between the physical presence of architecture and the possibilities to provide order and sensualisation throught its circulation system. Humans follow specific quotes of orientation, but architecture can especially offer certain guidelines. Although structural solutions require essential knowledge, this thesis further requests the double use of structure as a circulation pathway in addition. The high-scale urban environment of New York City provides ground for this investigation.Master of Architecture
3
Feddersen, Falk. "Nearshore circulation /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035923.
Testo completo
4
Wang, Yixiong. "Comparative planetary circulation regimes in simple general circulation models". Thesis, University of Oxford, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.669741.
Testo completoAbstract (sommario):
This thesis presents the studies of terrestrial planetary atmospheric circula- tion regimes using simplified GCMs with different levels of complexity. Two different versions of the simplified GCM PUMA (Portable University Model for the Atmosphere) are used — PUMA-S with Newtonian cooling scheme and PUMA-G with a semi-grey two-band radiative transfer scheme and dry convective adjustment. A series of controlled experiments are conducted by varying planetary rotation rate and imposed equator-to-pole temperature dif- ference using PUMAS-S, and by varying rotation rate, planetary obliquity, and the ratio of optical depth in long-wave (thermal radiation) band to that in short-wave (stellar radiation) band using PUMA-G. These defining parame- ters are further combined with each other into dimensionless forms to establish parameter spaces, in which the occurences of different circulation regimes are mapped and classified. For the PUMA-S experiments, very coherent trends when varying planetary rotation rate (thermal Rossby number) is found. It is demonstrated that the GRW mechanism is mainly responsible for the equato- rial super-rotation observed in our experiments. Regular baroclinic waves are obtained at intermediate values of thermal Rossby number and depend strongly on the strength of radiative and frictional damping. Global atmospheric ener- getics in terms of Lorenz energy cycle and meridional heat transport efficiency also exhibits strong dependence on planetary rotation rate from our PUMA-S experiments. Theories of geostrophic turbulence (especially the recently in- troduced zonostrophic turbulence) and jet formation are examined using the PUMA-S experiments. For the PUMA-G experiments, Similar trends are ob- served with respect to varying planetary rotation rate, while new regimes like strongly subrotating atmospheres are found when varying obliquity in PUMA- G. Tidally-locked planets are also studied by modifying the incoming stellar irradiation in PUMA-G. It is found that atmospheric optical depth in the long- wave band plays an important role in setting the heat transport efficiency from day-side to night-side. These results provide significant insights into the ter- restrial planetary atmospheric circulation dynamics and the inference of circu- lation regimes of extrasolar planets. Future studies will focus on the effect of seasonal/diurnal cycle, the parametrisation of eddy heat transport efficiency, as well as the modification of the two-band semi-grey radiative transfer scheme to incorporate pressure broadening effects
5
Nelkien, Haim. "Thermally driven circulation". Woods Hole, Mass. : Woods Hole Oceanographic Institution, 1987. http://hdl.handle.net/1912/3152.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, and (Ph. D.)--Woods Hole Oceanographic Institution, 1987.Cover title. Includes bibliographical references (leaves 181-186).
6
Nelken, Haim. "Thermally driven circulation". Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/58495.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 1987.Includes bibliographical references (leaves 181-186).
Several problems connected by the theme of thermal forcing are addressed herein. The main topic is the stratification and flow field resulting from imposing a specified heat flux on a fluid that is otherwise confined to a rigid insulating basin. In addition to the traditional eddy viscosity and diffusivity, turbulent processes are also included by a convective overturning adjustment at locations where the local density field is unstable. Two classes of problems are treated. The first is the large scale meridional pattern of a fluid in an annulus. The detailed treatment is carried out in two steps. In the beginning (chapter 2) it is assumed that the fluid is very diffusive, hence, to first approximation no flow field is present. It is found that the convective overturning adjustment changes the character of the stratification in all the regions that are cooled from the top, resulting in a temperature field that is nearly depth independent in the northernmost latitudes. The response to a seasonal cycle in the forcing, and the differences between averaging the results from the end of each season compared to driving the fluid by a mean forcing are analyzed. In particular, the resulting sea surface temperature is warmer in the former procedure. This observation is important in models where the heat flux is sensitive to the gradient of air to sea surface temperatures. The analysis of the problem continues in chapter 5 where the contribution of the flow field is included in the same configuration. The dimensionless parameter controlling the circulation is now the Rayleigh number, which is a measure of the relative importance of gravitational and viscous forces. The effects of the convective overturning adjustment is investigated at different Rayleigh numbers. It is shown that not only is the stratification now always stable, but also that the vigorous vertical mixing reduces the effective Rayleigh number; thereby the flow field is more moderate, the thermocline deepens, and the horizontal surface temperature gradients are weaker. The interior of the fluid is colder compared to cases without convective overturning, and, because the amount of heat in the system is assumed to be fixed, the surface temperature is warmer. The fluid is not only forced by a mean heat flux, or a seasonally varying one, but its behavior under permanent winter and summer conditions is also investigated. A steady state for the experiments where the net heat flux does not vanish is defined as that state where the flow field and temperature structure are not changing with time except for an almost uniform temperature decrease or increase everywhere. It is found that when winter conditions prevail the circulation is very strong, while it is rather weak for continuous summer forcing. In contrast to those results, if a yearly cycle is imposed, the circulation tends to reach a minimum in the winter time and a maximum in the summer. This suggests that, depending on the Rayleigh number, there is a phase leg of several months between the response of the ocean and the imposed forcing. Differences between the two averaging procedures mentioned before are also observed when the flow field is present, especially for large Rayleigh numbers. The circulation is found to be weaker and the sea surface temperature colder in the mean of the seasonal realizations compared to the steady state derived by the mean forcing. As an extension to the numerical results, an analytic model is presented in chapter 4 for a similar annular configuration.
by Haim Nelken.
Ph.D.
7
Dugas, Bernard. "Persistent circulation anomalies in observations and in a general circulation model". Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74220.
Testo completoAbstract (sommario):
A comparative diagnostic study of upper-air persistent atmospheric events, as simulated by a general circulation model (GCM) and as observed, is presented. We start with an overview of the several theories that attempt to explain such phenomena. Particular emphasis is put on the model approach of Shutts (1983). We next show that the spatial distributions of persistent events is qualitatively similar in the GCM and observational data. The North-Atlantic events are extracted and a rotated empirical orthogonal function (REOF) analysis is done on the resulting data sets. The two REOF sets that are thus obtained are shown to greatly resemble one another. Both explain roughly 50% of their original data's variance. The relationships between the modes within a set are presented, so as to understand their probable combined evolution. The fourth chapter contains an evaluation of Shutt's theory. There, the third chapter's results are used to isolate a particular class of events, namely the strong +ATL2 dipoles. The time-tendencies associated to short time-scale synoptic waves are evaluated, using an E-vectors approach, taking care to distinguish between the onset, mature and demise phases of the events. It seems that these synoptic waves have a significant impact of the average life-cycle of this +ATL2 type of events, whether they be simulated by a GCM or obtained from a NMC set of analyses.
8
Solberg, Robert Glen. "Extracorporeal Circulation: Effect of Long-Term (24-Hour) Circulation on Blood Components". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/32157.
Testo completoAbstract (sommario):
Extracorporeal circulation damages blood and causes harmful side effects such as stroke and/or systemic inflammatory response in patients. Reactions of blood components to extracorporeal circulation include complement and inflammatory reactions, coagulation and thrombogenesis, frank hemolysis, and platelet activation and adhesion to the extracorporeal circuit. Non-physiologic pressure and flow produced by blood pumps contribute to blood injury. Two pump types, roller and centrifugal, are used for maintaining flow, with various models available from different manufacturers. This study compared the effects of these two pumps in identical, isolated, artificial circuits to a non-pumped control for a period of 24 hours on heparinized porcine blood. Hematology parameters were used to evaluate blood damage. Mean corpuscular volume, mean corpuscular hemoglobin, white blood cell count, platelet count, and mean platelet volume were affected by time of circulation. Mean corpuscular hemoglobin, platelet count, and red cell distribution width were different between circulated and non-circulated blood, however no differences were found between the pumping systems in any parameter. Red blood cell count, total hemoglobin, and hematocrit were not affected by time or treatment. The changes observed in this study have implications for the use of extracorporeal circulation in the clinical setting and in future use of blood as a potential organ perfusion medium.Master of Science
9
Li, Hai. "Bile acids enterohepatic circulation". [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2005. http://dare.uva.nl/document/77982.
Testo completo
10
Bean, Mark Shawn. "Modelling the thermohaline circulation". Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242716.
Testo completo
11
Kontovourkis, Odysseas. "Computer-generated circulation diagrams". Thesis, University of Bath, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512302.
Testo completoAbstract (sommario):
The way in which computers are used is important in the theory, philosophy and practice of architecture. Architects are already using computers to construct complex three dimensional geometric models of their buildings and are beginning to analyse these models using environmental and structural software, a development which raises new questions about the role of architects and engineers. This dissertation puts forward the hypothesis that architects will at times need to be actively involved in computer programming by writing or modifying software. The hypothesis is based on the assumption that the form of a building and its spatial configuration are influenced by the nature of the design process itself. If architects are to have a complete and subtle control over design and to identify their own personal aesthetic language, they must also have control over the design process including the way computer software tools are developed and used. The hypothesis is tested using the example of a ferry terminal, a building type whose function is largely dominated by passenger circulation. Even thought passengers have a very straightforward aim to reach their final destination, the rules governing the way passengers move around the building are complex and a single computer program will not be able to cover all possible aspects of such behaviour. Thus, architects must have the freedom to formulate different rules and study the effects they have on their design. This particularly applies in non-emergency situations when each individual moves inside the building according to different needs and desires. A program was written which runs in real time so that the architect can see the effect of changing the parameters that control the process. The program can be used as evaluation mechanism to study the performance of postulated design or it can be use as creative mechanism where the design may emerge out of the process in the same way that animals create paths in the woods. Either way, the general aim is to optimize the design according to criteria over which the architect, again, must have complete control.
12
Ledain, Santiago Richard. "La circulation du cautionnement". Thesis, Evry-Val d'Essonne, 2011. http://www.theses.fr/2011EVRY0044.
Testo completoAbstract (sommario):
La circulation du cautionnement recouvre deux réalités que sont son transfert à titre particulier, en tant qu’accessoire d’un contrat garanti dont le bénéfice est transféré, et sa transmission, dans le cadre de la transmission universelle d’un patrimoine. Pareille circulation entre créanciers successifs de la garantie issue du cautionnement n’est pas entravée par sa nature juridique, analysée en tant qu’obligation de praestere, pas plus qu’elle ne l’est en considération des mécanismes permettant cette circulation, que sont respectivement la cession de créance et la transmission universelle de patrimoine. En effet, l’un comme l’autre vont opérer une substitution dans la personne du créancier bénéficiaire, préservant ainsi intact le lien d’obligation originaire, et permettre dès lors un maintien des pleins effets du cautionnement pour l’avenir, en l’absence de modification de l’objet de l’engagement de la caution. Néanmoins, la position de la jurisprudence française est pour l’heure toute autre, où en considération de la nature intuitu personae dont le cautionnement est traditionnellement emprunt, le juge va invariablement refuser le maintien de l’obligation de couverture de la caution, pour ne retenir que la survie de son obligation de règlement suite à la circulation de ce dernier. En matière de circulation à titre universel, la difficulté s’inscrit également sur le terrain du droit des sociétés. L’exception jurisprudentielle au principe de la transmission universelle de patrimoine s’oppose à la volonté du législateur français ayant souhaité faire de ce mécanisme une procédure simplifiée de transmission de l’ensemble a priori unique et indivisible qu’est le patrimoine. Le législateur européen tout comme celui de certains pays voisins accueillent toutefois favorablement une telle circulation.En considération de ces obstacles, certaines alternatives au cautionnement ont été envisagées, alors que sur le plan de la prospective, plusieurs adaptations permettraient d’achever une circulation effective de ce dernierTwo different realities with respect to a guarantee which are basically its isolated transfer, as an accessory to a contract which benefit is assigned, and its transmission, within the frame of a wider transaction resulting in an entire patrimony being transmitted, are overlapped by the concept of circulation. Such a circulation of the warranty arising out of a contract of guarantee among successive creditors is not restricted neither by the legal nature of the latter, that can be construed as an obligation of “praestere”, nor by the mechanisms authorising such a circulation, which are respectively the French “cession de creance” and “transmission universelle de patrimoine”. Both mechanisms shall operate a substitution with respect to the beneficiating creditor, so as to preserve the specifics of the original link created between guarantor and creditor, in order to maintain the full effects of the guarantee for the future, in the absence of any alteration of the guarantor’s commitment purpose. However, French case law currently departs from this interpretation and, in consideration of the nature “intuitu personae” which traditionally affects the guarantee, systematically refuses to maintain the commitment of the guarantor to guarantee the creditor for the future, only allowing the survival of an obligation of payment further to the circulation of the actual guarantee. With respect to the transmission of the guarantee, certain issues also relate to companies law. The exception created by French case law to the universal transfer of patrimony mechanism challenges the position of the French legislator whose objective was to entail the transmission of a patrimony, considered a priori as a unique and indivisible whole, trough a simplified procedure. The European legislator, in the same fashion as certain neighbouring countries’, welcomed such a circulation. In consideration of these obstacles, certain alternatives to the guarantee have been contemplated, while from a prospective perspective, several adaptations might allow an effective circulation of the latter
13
Walther, Connie. "Atmospheric Circulation in Antarctica". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199278.
Testo completoAbstract (sommario):
Validation of the Regional Climate Model HIRHAM with measurements, especially from radiosondes and GPS-signal-retrieval. Analysis of synoptical structures in Antarctica and comparison of the precipitation in different phases of the Antarctic Oscillation.
14
Iizawa, Isao. "Urban Heat Island Circulation". Kyoto University, 2009. http://hdl.handle.net/2433/123927.
Testo completoAbstract (sommario):
Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第14712号
人博第448号
新制||人||110(附属図書館)
20||人博||448(吉田南総合図書館)
UT51-2009-D424
京都大学大学院人間・環境学研究科環境相関研究専攻
(主査)准教授 酒井 敏, 教授 鎌田 浩毅, 教授 石川 尚人
学位規則第4条第1項該当
15
Rider, Kelly Elizabeth. "Shelf circulation patterns off Nigeria". Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/2252.
Testo completoAbstract (sommario):
Little has been published about the shelf circulation off the coast of Nigeria. Due to increased activity and associated incidents in the shallow waters offshore Nigeria, there is a need to more clearly define the near-shore circulation patterns. An oil spill occurred in January of 1998, the slick drifted in the opposite direction at twice the speed as was anticipated. It was believed that the heavy discharge from the Niger River Delta would have a strong influence on the near-shore circulation patterns and was the reason for this unexpected drift. This thesis investigates the river discharge by examining hydrographic data taken along the coastline. Using Acoustic Doppler Current Profilers, this thesis also investigates other possible forcing factors to gain an overall understanding of Nigeria??s shallow water circulation. Indeed river discharge plays an important role in the near-shore circulation as the coastal waters are highly stratified; however, the coastal waters are also strongly influenced by a cross-shelf semidiurnal tide, weather events and seasonal events, such as eddies and coastal upwelling. The resulting currents are a combination of a strong bi-directional cross-shelf tidal current with a strong bi-directional alongshelf current. The waters off Nigeria are highly stratified; they have spatial coherence and a uniform vertical structure along the coastline. These coastal waters may also be influenced by a remotely forced upwelling event and by northerly drift from the Congo River. The shelf circulation is clearly a complicated system and will require further investigation to be fully defined.
16
Cirovic, Srdjan. "Cerebral circulation during acceleration stress". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ58910.pdf.
Testo completo
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Khan, Sofia. "Studies in posterior circulation stroke". Thesis, St George's, University of London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.589798.
Testo completoAbstract (sommario):
Posterior circulation ischemic stroke accounts for a quarter of ischemic strokes. Recent studies have shown that these patients have a high early risk of further ischaemic events especially if they have 2:50% vertebrobasilar (VB) stenosis; there is paucity of data on the diagnosis and management of these patients. The gold standard technique to diagnose VB stenosis is intra-arterial angiography (IAA) which carries a risk of stroke; this can be avoided by using non-invasive imaging techniques. I systematically reviewed the literature on studies which compared the accuracy of three commonly used non-invasive imaging techniques (contrast-enhanced magnetic resonance angiography (CE-MRA), computed tomographic angiography (CTA) and duplex ultrasonography) to IAA, the gold standard, in order to diagnose VB stenosis. There were 13 studies for vertebral stenosis, these showed CE-MRA and possibly CTA to be better than duplex. I then performed the first prospective study (40 patients) comparing CE-MRA, CTA and duplex to IAA in the same patient group demonstrating that CE-MRA had the highest sensitivity followed by CTA and then duplex. The two main studies which have shown that 2:50% symptomatic VB stenosis carries a high risk of further ischaemic events followed-up patients for 90 days. I examined my patient group with longer term follow-up (mean 14 months). This study showed a higher risk of recurrent ischaemic events (odds ratio (OR) 2.56(95%CI 1.11-5.9),p=0.023) and VB stroke or TIA (OR 2.8(95%CI 1.24-6.32),p=0.01 ). I reviewed data from patients who had endovascular vertebral intervention at St George's and systematically reviewed the literature. This study showed that vertebral artery stenting is a technically successful procedure (99.4%) with a periprocedural stroke risk of 0.5%; one year TIA, stroke and mortality rate was 3.9%, 5.0%, and 3.6% respectively. However, the included studies were retrospective studies of varying quality; large-scale prospective trials are needed to determine the benefits of stenting.
18
Jones, Richard David. "Hypoxia and the pulmonary circulation". Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301608.
Testo completo
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Barrial, Dominique. "Contrôle pénal et circulation routière". Aix-Marseille 3, 1992. http://www.theses.fr/1992AIX32026.
Testo completoAbstract (sommario):
Le developpement toujours croissant de l'insecurite routiere met en evidence l'inefficacite des moyens de lutte contre la delinquance routiere. D'une part le controle penal auquel on a largement eu recours n'apparait plus comme une reponse adequate. Le droit penal routier est devenu un instrument dont l'objectif, marque par une grande diversite, est de plus oriente vers la maitrise non de la delinquance routiere mais des consequences pratiques de ce phenomene criminel. D'autre part, le recours a des controles de natures diverses renforce le caractere eclate et heterogene du controle. La perte d'unite tant dans l'objet des instruments de controle que dans leur nature doit etre enrauyee pour arriver a un droit objectivise par la securite routiereThe ever increasing phenomenon of insecurity on the highway clearly shows the ineffectiveness of the means used against road delinquency. On the one hand, punitive control, which has been widely used so far, now seems to be an inadequate response. The highway penal system hes become an instrument the aim of which, in its diversity, is to control the practical consequences of highway offenses, rather than to curb effectively that particular form of crime. On the other hand, the use of a variety of checks and controls reinforces the scattered and heterogeneous nature of the supervising of highway delinquency. Such a loss unity in the purposes, as well as in the instruments used for control activities, has to be counteracted if one is to reach a form of legal system that is clearly objectified by the concept of highway safety
20
Jasmin, Jean-François. "Système endothéline et circulation pulmonaire /". [Montréal] : Université de Montréal, 2003. http://wwwlib.umi.com/cr/umontreal/fullcit?pNQ92761.
Testo completoAbstract (sommario):
Thèse (Ph.D.) -- Université de Montréal, 2004."Thèse présentée à la Faculté des études supérieures en vue de l'obtention du grade de PhD en Physiologie" Version électronique également disponible sur Internet.
21
Su, Lin 1966. "A diagnostic study of the summer southern hemisphere circulation of the CCC general circulation model /". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60493.
Testo completoAbstract (sommario):
The medium scale planetary wave regime, consisting largely of zonal wavenumbers 5-7, frequently dominate the summer Southern Hemisphere tropospheric circulation. We perform a diagnostic study of this circulation as simulated by the Canadian Climate Centre (CCC) general circulation model (GCM). The analysis of Hovmoller diagrams, space-time and zonal wavenumber spectra shows that the CCC GCM is able to simulate the observed medium scale wave regime.The zonally averaged meridional eddy heat and momentum transports and the associated baroclinic and barotropic energy conversions are also examined. The distributions of the transports on the vertical plane agree well with observations. When compared to the observed summer 1979 distributions, some quantitative differences remain: the vertical structure of the heat transport is too baroclinic, while the momentum transport tends to be too weak. The baroclinic and barotropic conversions all show a medium scale wave signal. The time evolution of the Richardson number of the mean flow suggests that the medium scale wave is due to a finite amplitude baroclinic instability.
22
Saito, Ryu. "Influence of the surface on the atmospheric circulation of Mars : study with a general circulation model /". Katlenburg-Lindau : Copernicus, 2007. http://www.gbv.de/dms/bs/toc/535034385.pdf.
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Orr, Yishay Medical Sciences Faculty of Medicine UNSW. "Circulating neutrophil activation and recruitment during the systemic inflammatory response to cardiac surgery with extracorporeal circulation". Publisher:University of New South Wales. Medical Sciences, 2008. http://handle.unsw.edu.au/1959.4/41227.
Testo completoAbstract (sommario):
Circulating neutrophil activation occurs during cardiac surgery with extracorporeal circulation (ECC) and is implicated in the pathophysiology of inflammatory tissue injury and peri-operative organ dysfunction. However, neutrophil directed antiinflammatory strategies have failed to demonstrate consistent therapeutic benefit indicating that the nature and significance of peri-operative circulating neutrophil activation remains incompletely defined. In particular, conformational activation of the b2 integrin Mac-1 (CD11b/CD18), which is required for neutrophil adhesion competence and facilitation of effector functions, has not previously been investigated during cardiac surgery, and the relative contribution of cellular activation and bone marrow neutrophil recruitment to peri-operative changes in circulating neutrophil phenotype and function is unknown. A novel whole blood flow cytometric technique was used to analyze circulating neutrophil phenotype (total Mac-1, conformationally-active CD11b, CD10, CD16, L-selectin and P-selectin glycoprotein ligand-1) and function in cardiac surgery patients to characterize the nature of changes in Mac-1 expression and activation status, and the effects of relative neutrophil immaturity on circulating neutrophil phenotype and function. The effect of heparin, a known CD11b ligand, on Mac-1 epitope expression was also investigated. Circulating neutrophil numbers observed during ECC were mathematically modeled to determine the acute response of the bone marrow neutrophil reserve to an inflammatory stimulus. Plasma cytokine, chemokine and acute phase mediators were measured in cardiac and lung surgery patients to determine potential regulators of systemic neutrophil recruitment. Neutrophils newlyemergent from the bone marrow were characterized as CD10-/CD16low and exhibited distinct changes in cell surface markers and enhanced functional responses, relative to their more mature CD10+ counterparts. Conformational activation of CD11b occurred peri-operatively and provided a more sensitive measure of circulating neutrophil activation status than changes in total Mac-1 or L-selectin expression, although detection of Mac-1 epitopes was reduced in the presence of heparin. Modeling of circulating neutrophil numbers predicted that post-mitotic maturation time was acutely abbreviated by 8.4 hours during 71 minutes of ECC. Systemic chemokine release occurred with cardiac but not non-cardiac thoracic surgery indicating some specificity of the acute inflammatory response. These findings expand the understanding of peri-operative circulating neutrophil activation and recruitment, and identify potential therapeutic targets to limit neutrophil injurious potential during cardiac surgery with ECC.
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Marlot, Grégoire Crozet Yves. "Efficacité et acceptabilité de la régulation de la congestion". Lyon : Université Lumière Lyon 2, 2002. http://theses.univ-lyon2.fr/sdx/theses/lyon2/2002/marlot_g_notice.
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Henn, Vincent Faure René-Michel. "Information routière et affectation du trafic : vers une modélisation floue". [s.l.] : [s.n.], 2001. http://www.univ-lille1.fr/bustl-grisemine/pdf/extheses/50386-2001-Henn.pdf.
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Schirmer, Clemens. "Endovascular treatment of posterior circulation aneurysms". Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-14510.
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Brimioulle, Serge. "Acid-base status and pulmonary circulation". Doctoral thesis, Universite Libre de Bruxelles, 1990. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/213199.
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Simaga, Bamodi. "Circulation pulmonaire chez l'Africain sub-saharien". Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/240709.
Testo completoAbstract (sommario):
L’adaptation de la circulation pulmonaire à l’effort se fait essentiellement par l’augmentation de sa compliance. Cette distensibilité explique la chute de la résistance vasculaire pulmonaire (RVP). La résistance et la distensibilité vasculaire pulmonaire (α) à l’effort sont corrélées à l’aptitude aérobie. Cependant ces déterminants hémodynamiques majeurs de la circulation pulmonaire à l’effort sont modifiés par des caractères génétiques liés à l’origine géographiques et à l’appartenance au sexe masculin. Les sujets masculins Africains sub-sahariens ont une circulation pulmonaire moins distensible en réponse au débit cardiaque élevé en témoignent, leurs résistances vasculaires pulmonaires élevées, leurs pentes de relation multipoint pression artérielle pulmonaire moyenne débit cardiaque (PAPm-DC) raide. À cet effet, ils ont une moindre réserve vasculaire associée à une faible consommation maximale d’oxygène (VO2max), comparés aux Caucasiens appariés par l’âge, le sexe, le poids, la taille la dimension corporelle. Nous avons évalué l’aptitude aérobie de nos sujets par un test d’effort cardiorespiratoire incrémental sur bicyclette ergométrique. Il a permis la mesure des paramètres respiratoires et métaboliques (ventilation, consommation d’oxygène et production du dioxyde de carbone (CO2), de la fréquence cardiaque (Fc) et des pressions artérielles systémiques aux différents niveaux de l’effort. Il a aussi permis une analyse fine du comportement des sujets à l’effort, de la cause de leur limitation à l’effort. Des études préliminaires ont rapporté la faisabilité des mesures non invasives des paramètres hémodynamiques de la circulation pulmonaire au repos et à l’effort par échocardiographie. Il existe cependant une excellente corrélation entre les mesures des paramètres hémodynamiques de la circulation pulmonaire à l’effort obtenues par le cathétérisme cardiaque droit et celles recueillies par l’échocardiographie (R = 0,98). L’estimation du débit cardiaque et de la pression artérielle pulmonaire par échocardiographie à l’effort permet aussi une approximation raisonnable de leurs relations (PAPm-DC). À cet effet, nous avons jugé raisonnable d’évaluer l’état fonctionnel de la circulation pulmonaire des sujets par l’échocardiographie. La mesure de la capacité de diffusion pulmonaire qui est aussi une approche de la circulation pulmonaire nous a permis la mesure du composant membranaire de la diffusion pulmonaire et d’estimer le volume sanguin capillaire (Vc) par application de l’équation de Roughton et Forster pour l’oxyde nitrique et le monoxyde de carbone qui suit :1 / DL = 1 / Dm + 1 / θ.VcOù :• DL :diffusion pulmonaire,• Dm :diffusion membranaire,• θ :affinité pour l’hémoglobine,• Vc :volume capillaire. Plusieurs études ont démontré une corrélation entre le rapport taille assise / taille debout ou l’indice de Cormic et les volumes pulmonaires. À cet effet, la différence de proportion de taille entre les sujets d’origine Africaine et les Caucasiens Européens a une grande influence sur les volumes pulmonaires comme le volume expiratoire maximal en une seconde (VEMS) et de la capacité vitale forcée (CVF) ainsi que la capacité pulmonaire totale (CPT). Les études ont rapporté une diminution du VEMS et de la CVF chez les Afro-américains comparés aux blancs Caucasiens en rapport avec la différence de proportions du corps, la taille assise étant plus petite chez les descendants Africains que celle des Caucasiens. Cependant nous avons suggéré que cette différence de proportion de taille peut influencer la capacité de diffusion pulmonaire. Cela a été confirmé par les valeurs des paramètres de diffusion pulmonaire mesurées au repos et à l’effort chez les Africains et comparées à celles des sujets Caucasiens dans les mêmes conditions. Nous avons observé une diminution de volume alvéolaire (VA), de la DLNO, de la DLCO, et du Vc aussi bien entre les sujets masculins qu’entre les sujets féminins au repos et à l’effort. La différence interraciale de DLNO et de DLCO disparait quand on les corrige pour le VA. Le rapport DLNO / DLCO était aussi élevé au repos chez les Africains et persistait à l’effort. Les travaux de recherche réunis dans la présente thèse avaient pour but :(1) d’évaluer l’adaptation hémodynamique de la circulation pulmonaire à l’effort et de mesurer la capacité de diffusion pulmonaire au repos et à l’effort chez les sujets normaux Africains subsahariens et (2) de comparer les valeurs obtenues à celles mesurés chez les sujets normaux Caucasiens dans les mêmes conditions d’études, les sujets étant bien appariés par l’âge, le sexe, le poids, la taille et la surface corporelle.Dans une première étude, nous avons mesuré les paramètres hémodynamiques de la circulation pulmonaire à l’effort chez les sujets Africains et les comparer à ceux des sujets Caucasiens. Chez les sujets masculins Africains, la circulation pulmonaire était caractérisée par une résistance élevée, une faible distensibilité avec une réserve vasculaire diminuée corrélée à faible consommation maximale d’oxygène.Dans une seconde étude nous avons évalué l’effet de la dysanapsie sur la capacité de diffusion pulmonaire au repos et à l’effort. Les résultats montrent que les paramètres de diffusion pulmonaire (VA, DLCO, DLNO, et Vc) sont diminués aussi bien chez les sujets masculins que chez les sujets féminins Africains en rapport avec leur plus petit volume pulmonaire. Quand on corrige les valeurs de la DLNO et de la DLCO pour le VA, la différence interraciale disparaisse. Le rapport DLNO / DLCO était élevé chez les sujets Africains au repos et à l’effort. En conclusion :nos travaux de recherche ont démontré que :(1) la circulation pulmonaire est intrinsèquement résistive et moins distensible chez les sujets masculins Africains en réponse à un débit cardiaque élevé. Cet état fonctionnel diminue la réserve vasculaire pulmonaire et la consommation maximale d’oxygène, (2) la capacité de diffusion pulmonaire est aussi diminuée par l’effet de la dysanapsie chez les Africains subsahariens.Doctorat en Sciences biomédicales et pharmaceutiques (Médecine)
info:eu-repo/semantics/nonPublished
29
Bilyachenko, Alexey. "La circulation internationale des situations juridiques". Thesis, La Rochelle, 2016. http://www.theses.fr/2016LAROD001/document.
Testo completoAbstract (sommario):
La présente thèse part d’une tendance de la jurisprudence européenne, destinée à influencer la jurisprudence nationale de droit international privé, et se trouve dans le prolongement d’un grand débat doctrinal d’actualité. Il s’agit de la méthode de reconnaissance des situations juridiques, qui suppose l’abandon de la règle de conflit de lois. L’objectif est de conceptualiser cette nouvelle méthode et d’en définir le domaine et les conditions de mise en œuvre. Vu les particularités du sujet, la recherche passe nécessairement par plusieurs thèmes fondamentaux du droit international privé mais aussi du droit européen, du droit privé général et de la théorie du droitInspired by a trend in the European case law, which is meant to affect the national ones, the dissertation takes part to a topical debate among European academics on the putting aside the choice-of-law rules. It is about application of so-called recognition method to the foreign legal situations that haven’t been enacted in court. The purpose is to conceptualise this new method and to determine its scope and its modalities. Given the particularity of the task, the study necessarily bears on several pivotal topics of private international law but also of European law, general private law and jurisprudence
30
Kho, Tjioe Liang. "Dopamine and the circulation in man". Maastricht : Maastricht : Rijksuniversiteit Limburg ; University Library, Maastricht University [Host], 1987. http://arno.unimaas.nl/show.cgi?fid=5365.
Testo completo
31
Ruissen, Cornelis Jan. "Fetoplacental circulation measurements, techniques and applications /". Maastricht : Maastricht : Datawyse ; University Library, Maastricht University [Host], 1990. http://arno.unimaas.nl/show.cgi?fid=5597.
Testo completo
32
Brandefelt, Jenny. "Atmospheric circulation regimes and climate change". Doctoral thesis, Stockholm : Dept. of Meteorology, Stockholm University, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-530.
Testo completo
33
Shrewsbury, George D. "Dynamic stall of circulation control airfoils". Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/12397.
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34
De, Neeve Eileen O'Brien. "Bernard Lonergan's "Circulation analysis" and macrodynamics". Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74336.
Testo completoAbstract (sommario):
Bernard Lonergan's economic writings have not been fully evaluated by economists although two recent papers by Burley (1989a, 1989b) show that work has begun. The purpose of this dissertation, therefore, is to situate Lonergan's (1944) economics essay, Circulation Analysis, in the history of economic thought of the period as well as to present a Lonerganian cycle model.Circulation Analysis examines fundamental macrodynamic processes to explain fluctuations. It was written in the early 1940s following a period of controversy and debate that led to the current paradigms of economic dynamics. The two sides of the debate are exemplified by Harrod (1936) and Hayek (1933 (1928), 1939), in particular. The controversy ended with World War II and the emerging hegemony of the Anglo-American approach, which separated macrodynamics into growth theory (long-run supply problems), and stabilization theory (short-run demand problems).
This dissertation argues that this dichotomy is unsatisfactory and proposes Lonergan's pure cycle as an alternative paradigm. Lonergan's pure cycle restores the importance of supply-side dynamics in the short-run, without denying the primacy of demand issues in the analysis of deviations. A Lonerganian approach views demand shocks as essentially monetary, but also contends that the distribution of nominal income can cause shocks, if it is not synchronized with changes in real variables.
In this thesis a Lonerganian model is presented that uses a Kydland-Prescott (1982) type of "time-to-build" technology. The model is subjected to permanent productivity shocks to investment, which explain, with a lag, equilibrium output. The monetary and distributional shocks to demand, which are temporary, can then explain the deviation of actual output from its equilibrium value. The model uses a Beveridge and Nelson (1981) approach, which specifies changes in growth rates of variables as a function of permanent and temporary shocks. The shocks are identified because the model is recursive: first, the productivity shock determines investment and equilibrium output; then, the monetary shock determines prices and sales of consumer goods. Simulation results are presented.
35
Gillett, Nathan Peter. "Climate change and the atmospheric circulation". Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393444.
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36
Jones, Matthew Stephen. "Satellite techniques for studying ocean circulation". Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.568439.
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37
Santer, B. D. "Regional validation of General Circulation Models". Thesis, University of East Anglia, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383549.
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Stephens, James C. "Aspects of the oceanic thermohaline circulation". Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342459.
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39
Thomas, Margot Ross. "Fetal cells in the maternal circulation". Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363337.
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40
Williams, David Reid. "The pulmonary circulation at high altitude". Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316610.
Testo completo
41
Forster, M. "Computational modelling of transonic circulation control". Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3018248/.
Testo completoAbstract (sommario):
This Ph.D. thesis focusses upon computational fluid dynamics simulations of circulation control in transonic freestream speeds for applications to unmanned combat air vehicles. The work addresses Coanda shape designs and their effectiveness for transonic circulation control using supersonic jets, with comparisons against traditional control surfaces. Previous works have thus far only investigated transonic circulation control on elliptical sectioned wings with unrepresentatively thick trailing edges and improvements in performance made by considering elliptical Coanda devices or increasing radii of curvature. In this work, a supercritical aerofoil was first modified to accommodate a small Coanda surface with minimal effects on the base drag and a comparison made between the performance of using several Coanda designs and a hinged control surface. The use of a step was demonstrated to make a circulation control device with a simple converging nozzle as effective as ailerons and flaps up to moderate deflection angles and that the limitations are due to breakdowns in the mean flow in a similar fashion to traditional devices. In addition an optimisation study was performed using modern numerical methods on the contouring of the Coanda surface, which identified a shape that performed well for both transonic and subsonic freestream conditions. Circulation control was then applied to a three-dimensional unmanned combat air vehicle planform and assessed at transonic conditions for use in roll, pitch and yaw control. From the range of conditions investigated the findings suggest that, for a three-dimensional representative geometry, circulation control can match the performance of conventional controls for roll and pitch. The results also suggest that for benign transonic conditions, circulation control can also provide control similar effectiveness to split flaps for yaw control. The findings open up insights into transonic circulation control and hopefully will promote further research in both academia and industry, where a lack of CFD validation quality experimental data for a transonic test case with supersonic blowing prohibits the technology from advancing.
42
Mardapitta-Hadjipandeli, Lida. "Numerical modelling of tide-induced circulation". Thesis, University of Birmingham, 1986. http://etheses.bham.ac.uk//id/eprint/4529/.
Testo completoAbstract (sommario):
A finite difference computational model has been enhanced and refined to simulate tide-induced circulatory flows, with special reference to eddies shed in the lee of headlands and tidal circulation and flushing in narrow entranced coastal basins. The model is of the two-dimensional depth-integrated type and includes a relatively simple "zero-equation" turbulence model. In the turbulence model particular emphasis has been placed on the representation of the free shear layer turbulence, occurring in the mixing zone of eddying flows. This component of turbulent structure has been expressed in terms of a constant eddy viscosity across the shear layer and a semi-empirical velocity distribution. The finite difference representation of the hydrodynamic and mass transport equations was based on the Alternating Direction Implicit scheme, with the hydrodynamic equations involving a double iteration to represent the advective acceleration terms in a time-centred form. The solution of the governing equations yielded the depth-mean velocity, water elevation and concentration fields throughout the computational domain.The model's ability to simulate tide-induced circulatory flows was tested against field measurements from around Rattray Island, and laboratory model studies of idealised rectangular harbours. The agreement between numerical predictions and measurements proved to be encouraging in both cases. The one-way interaction nesting technique has been adopted and applied with success to the harbour simulations. A final application of the numerical model to prototype harbours, enabled comparisons to be made between prototype and laboratory model predictions, an exercise which highlighted the problems associated with scaling effects in distorted physical models.
43
Lucarini, Valerio. "Thermohaline circulation stability : a box model". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/30128.
Testo completoAbstract (sommario):
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2003.Includes bibliographical references (leaves 87-97).
A thorough analysis of the stability of uncoupled and coupled versions of an inter-hemispheric 3-box model of Thermohaline Circulation (THC) is presented. The model consists of a northern high latitudes box, a tropical box, and a southern high latitudes box, which respectively can be thought as corresponding to the northern, tropical and southern Atlantic ocean. We study how the strength of THC changes when the system undergoes forcings that are analogous to those of global warming conditions. In each class of experiments, we determine, using suitably defined metrics, the boundary dividing the set of forcing scenarios that lead the system to equilibria characterized by a THC pattern similar to the present one, from those that drive the system to equilibria where the THC is reversed. In the case of the uncoupled model, we apply to the equilibrium state perturbations to the moisture and heat fluxes into the three boxes. High rates of increase in the moisture flux into the northern high-latitude box lead to a THC breakdown at smaller total final increases in the moisture flux than low rates, while the presence of moisture flux increases into the southern high-latitude box strongly inhibit the breakdown and can prevent it, in the case of slow rates in the Northern Hemisphere. Similarly, a fast heat flux increases in the North Hemisphere destabilize the system more effectively than slow ones, and again the enhancement of the heat fluxes in the Southern Hemisphere tend to drive the system towards stability. In all cases analyzed slow forcings, if sufficiently weak in the Southern Hemisphere, lead to the reversal of the THC.
(cont.) In the coupled model a direct representation of the radiative forcing is possible, since the main atmospheric physical processes responsible for freshwater and heat fluxes are formulated separately. Although only weakly asymmetric or symmetric radiative forcings are representative of physically reasonable conditions, we consider general asymmetric forcings, in order to get a more complete picture of the mathematical properties of the system. We also consider different choices for the atmospheric transport parametrizations and for the ratio between the high latitude to tropical radiative forcing, and analyze the sensitivity of our results to changes in these parameters. We generally find that fast forcings are more effective than slow forcings in disrupting the present THC patterns, forcings that are stronger in the northern box are also more effective in destabilizing the system, and that very slow forcings do not destabilize the system whatever their asymmetry, unless the radiative forcings are very asymmetric and the atmospheric transport is a relatively weak function of the meridional temperature gradient. The changes in the strength of the THC are primarily forced by changes in the latent heat transports, because of their sensitivity to temperature that arises from the Clausius-Clapeyron relation.
by Valerio Lucarini.
S.M.
44
Guma, Anthony C. (Anthony Christian) 1975. "Urban Relay : circulation morphology [accelerator city]". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8755.
Testo completoAbstract (sommario):
Thesis (M.Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 2001.Includes bibliographical references (p. 98-99).
Generally, in the contemporary cities vertical buildings are conceived and implemented as subdivided volumes that set up highly regularized modes of inhabitation. This condition limits the possibility for more complex and adaptive spatial relationships between program and use. This limitation exists at a time when the relationship between individuals and their patterns of living is becoming increasingly more complex. This thesis will explore the design of the mixed-use building through a study of program, circulation, skin, and form. Sited in Boston at a point of intersection between programs, people, and of conflicting physical parameters, this project will develop a system to (re)organize space within a given volume and the flows through it. This system of programmatic organization will be mediated through a responsive network of circulation and the articulation of surfaces that frame the minimal spaces between uses.
Anthony C. Guma.
M.Arch.
45
Noble, Taryn Lee. "Southern Ocean circulation and sediment sourcing". Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610485.
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46
Hobbs, Kyle. "Thermally driven natural circulation water pump". Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97066.
Testo completoAbstract (sommario):
Thesis (MEng)--Stellenbosch University, 2015.ENGLISH ABSTRACT: The water utilized by passive air-conditioning systems in buildings is typically required at higher elevations. The thermally driven natural circulation water pump (TDNCWP) is a passively driven pumping system for delivering water from ground level against gravity to a higher elevation. It consists of a humid air closed duct loop to which a temperature difference is applied, resulting in a density gradient driven flow. A hot water evaporation tray inside the loop at ground level introduces water vapour to the loop air flow, and a cold condensation plate inside the loop at the elevated level removes this water vapour for passive airconditioning usage. In this thesis, a one-dimensional theoretical and numerical simulation model is developed. Experiments were conducted on two experimental TDNCWP set-ups of different cross sectional areas to evaluate the pump design and the theoretical model. It is shown in this thesis that the TDNCWP can provide water at varied elevations using non-mechanical, passive means. A temperature difference of 9 to 12.5 °C induced an average velocity of 0.4 to 0.6 m/s for a duct cross section of 100 mm2. For a larger cross section of 400 mm2, a temperature difference of 2 to 5 °C induced an average velocity of 0.25 to 0.3 m/s. An asymmetrical velocity profile was observed which varied at different points in the loop. A water delivery rate of 1.2 to 7.5 L/day was experimentally determined which compares well to the passive air-conditioning water requirements of a small building. The theoretical model over-predicted the delivery rate at increased duct cross sectional areas but fared well when compared to the smaller experimental model results. Further refinement of the numerical model and the TDNCWP design is required, and recommendations were made regarding this. It is clear however that the TDNCWP provides an alternative to a conventional water pump for low-volume water pumping requirements.
AFRIKAANSE OPSOMMING: Die water wat gebruik word deur passiewe lugversorgingstelsels in geboue word tipies benodig op hoër vlakte. Die termies gedrewe natuurlike sirkulasie waterpomp (TDNCWP) is ʼn passiewe gedrewe pomp stelsel vir die lewering van water vanaf die grondvlak teen swaartekrag na ʼn hoër vlak. Dit bestaan uit 'n vogtige geslote lug geut siklus waarop ʼn temperatuur verskil toegepas word, dit lei tot vloei gedrewe deur ʼn digtheids gradiënt. ʼn Warm water verdampings-pan binne die geut op grondvlak stel waterdamp aan die geut lugvloei toe, en ʼn koue kondensasie plaat binne die geut op die verhoogde vlak verwyder hierdie waterdamp vir passiewe lugversorgings gebruik. In hierdie tesis word ʼn eendimensionele teoretiese en numeriese simulasie model ontwikkel. Eksperimente is uitgevoer op twee eksperimentele TDNCWP stelsels van verskillende deursnee grootes om die pomp ontwerp en die teoretiese model te evalueer. Die tesis dui aan dat die TDNCWP water kan voorsien teen verskillende hoogtes op ʼn nie-meganiese, passiewe wyse. ʼn Temperatuur verskil van 9 tot 12.5 °C veroorsaak ʼn gemiddelde snelheid van 0.4 tot 0.6 m/s vir ʼn geut deursnit van 100 mm2.Vir ʼn groter deursnit van 400 mm2, het ʼn temperatuur verskil van 2 tot 5 °C ʼn gemiddelde snelheid van 0.25 tot 0.3 m/s veroorsaak. ʼn Asimmetriese snelheidsprofiel was waargeneem wat gewissel het op verskillende punte in die siklus. ʼn Water voorsienings tempo van 1.2 tot 7.5 L / dag was eksperimenteel waargeneem wat goed vergelyk met die passiewe water lugversorging vereistes van 'n klein gebou. Die teoretiese model het ʼn groter voorsienings tempo voorspel vir die groot deursneë, maar het goed gevaar in vergelyking met die kleiner eksperimentele model. Verdere verfyning van die numeriese model en die TDNCWP ontwerp word vereis, en aanbevelings is gemaak ten opsigte van hiervan. Dit is egter duidelik dat die TDNCWP ʼn alternatief is vir konvensionele lae-volume water pomp applikasies.
National Research Foundation (NRF)
47
Hawker, Elizabeth J. "The Nordic Seas circulation and exchanges". Thesis, University of Southampton, 2005. https://eprints.soton.ac.uk/18669/.
Testo completoAbstract (sommario):
The Nordic Seas provide the main oceanic connection between the Arctic and the deep global oceans via dense overflows between Greenland and Scotland, into the North Atlantic. An understanding of the circulation and exchanges of this region is vital for any consideration of the implications of high latitude climate change to variability in the Atlantic thermohaline circulation and consequences for regional (European) climate. This thesis makes use of a unique data set of near synoptic hydrographic and LADCP (lowered acoustic Doppler current profiler) measurements across the entire region during summer 1999. The box inverse method is applied to this hydrographic data, using computed geostrophic velocities referenced to detided LADCP measurements. The full summer Nordic Sea flux field (volume, heat and freshwater) is quantified, studying both the exchanges across the openings to the Nordic Seas, and the interior circulation. The total volume transports imply an inflow of 1.3 ± 0.5 Sv to the Nordic Seas from the Arctic Ocean, and a net export of 1.2 ± 0.5 Sv across the Greenland-Scotland Ridge into the North Atlantic. Within the Nordic Seas 4.0 ± 1.3 Sv of the warm saline inflow (s0 < 27.8) are converted to more dense waters, with the majority of the transformation (and ocean-atmosphere heat loss) occurring over the southern part of the Nordic Seas. The total heat convergence within the Nordic Seas is 137 ± 44 TW, giving an average flux of 51 ± 16 W m–2, and the net input of freshwater to the Nordic Seas is 0.059 ± 0.019 Sv. The sensitivity of the summer circulation and fluxes is investigated; considering the formal error estimates from the inverse model, together with the errors implied from inverse and oceanographic sensitivity tests. Supplementary winter data is used to construct a winter circulation providing an indication of significant seasonal variability. This infers that an estimate of the annual mean fluxes based on summer data alone cannot be justified.
48
Aweda, Moses Adebayo. "Microcapteurs : application en circulation extra-corporelle". Toulouse 3, 1988. http://www.theses.fr/1988TOU30213.
Testo completoAbstract (sommario):
Ce travail concerne l'étude des microcapteurs pour les mesures in-vivo en continu des paramètres sanguins au cours d'une circulation extracorporelle (CEC), et en particulier le pH et la conductivité ionique du sang. Une brève présentation de CEC précède un rappel succinct des principes de fonctionnement des différents microcapteurs de pH. Les mesures invasives dans le sang posent un certain nombre de problèmes du fait des systèmes de défense immunologique. Une étude de quelques membranes biocompatibles et semi-perméables aux ions a été réalisée, le but étant l'application à l'interface sang/microcapteur. Les microcapteurs de pH en Ir/Ir02 ont été revêtus de ces membranes biocompatibles. L'encapsulation du microcapteur de conductivité ionique sous une forme utilisable dans une CEC, et la réalisation d'un conductimètre adapté ont été effectuées. Un système informatisé d'acquisition des données, permettant le monitorage simultané et continu des paramètres sanguins dans une CECpendant quelques heures a été réalisé. La fiabilité des microcapteurs étudiés et du système d'acquisition des données a été testée dans une CEC avec un mouton pendant environ six heuresThis work is a study of microsensors for continuous in-vivo measurements of blood parameters during extracorporeal circulation (ECC), in particular blood pH and ionic conductivity. A brief introduction of ECC has been given, follo[w]ed by a concise summary of the working principles of different pH microsensors. Invasive measurements are faced with a number of problems due to the immunological defence systems in the blood. Some biocompatible and semipermeable membranes have been studied for use as materials for blood/microsensor interfaces. The Ir/Ir02 pH microsensors have been coated with these biocompatible membranes. The packaging of the ionic conductivity microsensor in a convinient form for use in an ECC has been done and a suitable conductimeter designed. A computerized data acquisition system, suitable for simultaneous and continuous monitoring of blood parameters during an ECC for some hours has been built. The performance of the microsensors and the data acquiston system was tested for about six hours in an ECC with a sheep
49
Fleury, Laurence. "Equilibres multiples de la circulation thermohaline". Toulouse 3, 1996. http://www.theses.fr/1996TOU30137.
Testo completoAbstract (sommario):
A l'echelle planetaire, les forcages de chaleur et d'eau douce agissent de facon antagoniste sur le champ de densite de surface de l'ocean. Cette competition entre les effets thermique et salin autorise plusieurs modes operatoires de la circulation dite thermohaline. Ses equilibres multiples sont ici etudies via la comparaison entre un modele numerique bidimensionnel et une equation asymptotique derivee dans la limite d'une couche oceanique fine. Les resultats des simulations numeriques et les solutions asymptotiques, obtenus avec differents forcages, presentent des similitudes mais egalement des differences qui sont exprimees a l'aide de criteres simples. Ainsi l'analyse asymptotique s'avere un outil simple et puissant de prediction des equilibres simules. Ensuite, une methode de suivi des solutions stationnaires dans l'espace des parametres a ete utilisee pour etudier l'equation asymptotique. La structure bifurcatoire observee est analogue a celle du modele bidimensionnel. Une parametrisation de la rotation et du forcage dynamique est introduite dans chacun des modeles. Leur symetrie peut etre brisee et leurs diagrammes de bifurcation evoluent de facon analogue.
50
Antony, Isabelle. "Circulation coronaire dans l'hypertension arterielle essentielle". Paris 6, 1998. http://www.theses.fr/1998PA066388.
Testo completoAbstract (sommario):
Ce travail aborde les anomalies de la circulation coronaire mises en evidence chez des patients hypertendus sans autre facteur de risque cardiovasculaire, dont les arteres coronaires sont angiographiquement normales. Ces anomalies, presentes au stade precoce de l'hypertension arterielle, concernent les gros troncs epicardiques et la microcirculation coronaire. La diminution de conductance des arteres coronaires epicardiques (reduction de leur calibre), les perturbations de la vasomotricite des arteres coronaires epicardiques et resistives (etude de la vasodilatation flux-dependante et de la reponse au test au froid), et la diminution de la surface de section maximale de la microcirculation coronaire (diminution de la reserve coronaire) pourraient avoir des effets additifs et limiter de facon significative l'augmentation du debit coronaire necessaire a l'augmentation de la demande en oxygene du myocarde, provoquant des episodes hypoxiques ou anoxiques symptomatiques (angor) ou asymptomatiques (ischemie silencieuse). Le role de l'endothelium est fondamental dans les anomalies de la vasomotricite coronaire. La dysfonction coronaire endotheliale est commune a l'hypertension arterielle et aux autres facteurs de risque cardiovasculaire, et l'endothelium vasculaire a aussi un role cle dans la physiopathologie de l'atherogenese et de la thrombogenese. Les effets du traitement antihypertenseur paraissent prometteurs sur la reserve coronaire (antagonistes des canaux calciques et inhibiteurs de l'enzyme de conversion), et sur la vasomotricite coronaire des arteres epicardiques et resistives (inhibiteurs de l'enzyme de conversion). Des etudes devront etre realisees chez l'hypertendu afin de savoir si certaines classes therapeutiques peuvent diminuer la morbidite/mortalite cardiaque, et par quels mecanismes.