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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
491

乱流中の変動圧力の計測について

辻, 義之, TSUJI, Yoshiyuki, 今飯田, 純, IMAIIDA, Jun, 阿部, 浩幸, ABE, Hiroyuki 07 1900 (has links)
No description available.
492

Asymptotic Behaviour of Capillary Problems governed by Disjoining Pressure Potentials

Thomys, Oliver 05 August 2010 (has links) (PDF)
Introduction Capillarity describes the effects caused by the surface tension on liquids. When considering small amounts ofliquid,thesurfacetension becomes the dominating parameter. In this situation the arising mathematical task is to determine the occurring capillary surface. At the beginning of the research on this topic, problems such as the ascent of fluids in a circular tube, on a vertical wall or on a wedge were some of the first problems scientists were concerned with. At the beginning of the 19th century, scientists like Young1, Laplace2, Taylor 3 and Gauß 4 established the mathematical foundations of this field. For the capillary tube5 they found, by applying variational methods, the so called mean curvature equation or capillary equation with the associated boundary condition. As Finn in [Fin86, Chapter 1] describes, this leads to the following boundary value problem: divTu = u + in , · Tu = cos on @ where Tu = ∇u p 1 + |∇u|2 . is called the Lagrange6 multiplier and is the contact angle, established between the capillary surface and the container wall. In the past, one tried to solve the problem by linearisation – with more or less satisfying results. In the last decades, expedited by the developing of micromechanics and the arising space-technology, capillary effects became more and more significant. Thereby the observed results differed from the predicted. The reason is the strong non-linearity of the problem. Interior molecular forces are responsible for the establishing of equilibrium surfaces. The force, operating between two materials, is called adhesion and cohesion is the molecular force within a medium. Under some specifications there arises a non-negligible force, called disjoining pressure. This pressure causes an additional term in the capillary equation, which 1Thomas Young (*13 June 1773, Milverton; †10 May 1829, London); Englisch polymath; made notable contributions to the fields of vision, light, solid mechanics, energy, physiology, language, musical harmony and Egyptology, found the Young–Laplace equation 2Pierre-Simon (Marquis de) Laplace (28 March 1749, Beaumont-en-Auge; †5 March 1827, Paris); French mathematician and astronomer; found the Young–Laplace equation 3Brook Taylor (*18 August 1685, Edmonton; †29 December 1731, Somerset House/London); English mathematician; experiments in capillary attraction 4Johann Carl Friedlich Gauß (*30 April 1777, Braunschweig; †23 February 1855, G¨ottingen); German mathematician and scientist; contributed significantly to many fields, including number theory, statistics, analysis, differential geometry, geodesy, geophysics, electrostatics, astronomy and optics 5A capillary tube is a container with cross-section and perpendicular container walls, which contains an amount of liquid. 6Joseph-Louis de Lagrange (*25 January 1736, Turin; †10 April 1813, Paris); Italian mathematician and astronomer. 7 is called the disjoining pressure potential, denoted by P(x, u(x)). That is, we are led to the following modified capillary equation, see [MMS08]: divTu = u + P + in , with a similar boundary condition (see Section 1.3 for more details). The main task of this paper is to examine the behaviour of the capillary problem, considering the disturbance P. A generic example for such configurations is vapour nitrogen//liquid nitrogen//quartz, see also [Isr92, Chapter 11] or [MMS08]. The present work with regard to contents is divided in three parts. In the first part, inspired by the work of Concus and Finn [CF74], [FH89], we prove a Comparison Principle. As in the classical context, this principle is a powerful tool to find solutions of the boundary problem. Thus we can see that the disjoining pressure potential is the key for the asymptotic of the solutions. The second part is concerned with the asymptotic behaviour of the solutions for some classical cases. In particular for the capillary tube with circular cross-section (see [Mie93b], [Mie94], [Mie96] for the classical setting) the ascent on a horizontal wall and between two parallel horizontal plates, results are presented. There we are able to specify the asymptotic behaviour up to a constant term. In the last part we observe the solution of the problem on a corner. There it is more difficult to obtain a result. But in return, we gain a better result near the cusp of the edge. In the articles of Miersemann [Mie88], [Mie89], [Mie90] or Scholz [Sch04] some results for the classical setting are given. The formal arrangement is divided into three main chapters. The first of them is a summary of some notations which will be needed in the following chapters and also the physical background is illuminated. The main part, where asymptotic results are presented, is contained in Chapter 2. To afford a better reading, most of the proofs are given in Chapter 3.8
493

Studies on the effects of hydrostatic pressureon rat retinal ganglion cell line RGC5.

Li, Shaojuan, Medical Sciences, Faculty of Medicine, UNSW January 2008 (has links)
Glaucoma is characterized by retinal ganglion cell apoptosis leading to a corresponding loss of the visual field. Elevated intraocular pressure is the principal clinical association of this disease and its reduction remains the mainstay of current therapy. This research established an in-vitro glaucoma model and investigated the direct effects of increased hydrostatic pressure on retinal ganglion cell survival as well as the cellular response to changes in pressure. In the first part of this thesis (chapter 3) the direct effects of pressure on retinal ganglion cell survival was established. The differentiated RGC5 cell line was subjected to elevated pressure 100 mmHg for a period of two hours in a pressure chamber. Cell apoptosis was then detected by TdT-mediated dITP Nick-End Labelling (TUNEL). Quantitative analysis of the percentage of apoptotic cells between the control and pressure groups by Laser Scanning Cytometry (LSC) revealed that pressure alone induced significant apoptosis. Furthermore, caspase-3 cleavage was detected in the pressure treated cells by Western blot analysis. The next three chapters investigated how the applied pressure may be mediated through cellular mechno-sensitive structures. TWIK Related Arachiodonic Acid stimulated K+ channel (TRAAK) is a mechano-gated neuronal potassium channel, which can be opened by pressure and arachidonic acid. In chapter 4, TRAAK was identified as expressed on the rat RGC5 cell line. This was determined by both immunostaining and RT-PCR. Opening this channel by arachidonic acid induced significant apoptosis in RGC5 neurons; elevated extracellular K+ concentration and blockage of TRAAK by gadolinium inhibited both arachidonic acid and pressure-induced apoptosis. These results indicated that elevated pressure resulted in opening of the outward potassium channel-TRAAK and consequently potassium ion efflux and apoptotic volume decrease (AVD). Data from chapter 5 revealed that pressure also caused actin reorganization with both F- and G-actin shifts. At the early stage (following 2 hours pressure treatment), actin polymerization led to G-actin pool decrease and disinhibition of DNase1 in the cytoplasm. This has been suggested to lead to DNase1 nuclear translocation and contribution to DNA fragmentation associated with apoptosis. The preliminary microarray results of chapter 6 revealed pressure effects on gene expression Included in the many up- and down-regulated genes was; down-regulation of antiapoptotic gene- BcL-x and up- regulation of Damage-Induced Neuronal Endopeptidase (DINE) after pressure treatment. This study showed that elevated pressure induced RGC5 apoptosis and affected multi cellular mechanosnesitive structures. These results may indicate new mechanisms of RGC neuron apoptosis and further therapeutic strategies.
494

Aircraft noise and child blood pressure

Morrell, Stephen Louis January 2003 (has links)
The purpose of the study was to examine the existence of an association between child blood pressure (BP) and exposure to domestic jet aircraft noise in the context of the construction of a new parallel north-south runway at Sydney (Kingsford-Smith) Airport. The baseline study was commissioned and funded by the Federal Airports Corporation (FAC), with measurements conducted in 1994 and 1995. A follow-up longitudinal component to the study was subsequently commissioned and funded by the FAC in 1997, and measurements conducted in the same year. As the same individuals were measured and re-measured over changing conditions of exposure to aircraft noise, the quasiexperimental nature of the study allowed inferences to be made regarding exposure to aircraft noise and child BP. The main hypotheses for testing were that BP, and within-subject longitudinal changes in BP, are positively related to domestic jet aircraft noise exposure and longitudinal changes in domestic jet aircraft noise exposure respectively. Subsidiary hypotheses tested for evidence of short- and long-term BP adaptation effects where BPs were related to prior changes to aircraft noise exposures. A sample of 75 primary schools within a 20 km radius of Sydney Airport under various noise exposure conditions, both existing and those projected with the advent of the new runway, participated in the study. The baseline cohort comprised 1,230 Year 3/4 children attending the schools in 1994 and 1995, and the follow-up participants comprised 628 of the original baseline sample re-measured in 1997. Study participants were enrolled by active parental consent. The baseline response rate was approximately 40% of children in the participating schools. Systolic (SBP) and diastolic (DBP) blood pressure readings of the children were taken using automated BP measuring equipment along with anthropometric measurements (heights, weights, skinfold thicknesses and waist measurements). Parental surveys captured items pertaining to the child�s ethnic background as measured by the country of birth of the child and parent(s), residential address and housing structure, child eating habits and activity levels, along with family and child history of high blood pressure. Aircraft noise exposure data were collected by the National Acoustic Laboratories and processed into the energy-averaged noise metric used in Australia for aircraft noise exposure assessment called the Australian Noise Exposure Index (ANEI). Mean exposures for a given calendar month were used in the analysis. ANEI values were geocoded to exact geographic locations using digitised street maps from which values for each house and school address, also geocoded, were interpolated. A child BP measured in a given month was matched to a aircraft noise exposure value both at their school and residential address for that month for analysis. After adjusting for confounding and other factors, the cross-sectional relationship between BP and aircraft noise exposure was found to be inconsistent. SBP was nonsignificantly negatively associated with school aircraft noise exposure at baseline (0.05 mmHg/ANEI, cluster-sampling-adjusted p&gt0.05), but positively and non-significantly associated with school aircraft noise exposure at follow-up (0.05 mmHg/ANEI, p&gt0.05). As for SBP, baseline DBP was significantly negatively related to school aircraft noise exposure at (0.09 mmHg/ANEI, p&lt0.001) and non-significantly positively associated with school aircraft noise exposure at follow-up (0.05 mmHg/ANEI, p&gt0.05). Within-subject BP changes, occurring from baseline to follow-up, regressed on corresponding longitudinal changes in aircraft noise exposures produced inconsistent results. SBP change was positively and non-significantly (0.027 mmHg/ANEI, p&gt0.05) associated with corresponding school aircraft noise exposure change, while SBP change was negatively associated total aircraft noise exposure change (statistically nonsignificant, 0.06 mmHg/ANEI, p&gt0.05). DBP changes were similarly and nonsignificantly related to corresponding aircraft noise exposure changes. Some evidence for short-term BP adaptation to recent changes in aircraft noise exposure was found. Consistent negative associations between systolic and diastolic BP and recent changes in school aircraft noise exposure were found. This association was statistically significant at study baseline (SBP: 0.19 mmHg/ANEI, p&lt0.001; DBP: 0.12 mmHg/ANEI, p&lt0.001), and of similar magnitude although not statistically significant at follow-up (SBP: 0.14 mmHg/ANEI; DBP: 0.10 mmHg/ANEI, p&gt0.05). In the presence of inconsistent cross-sectional BP-aircraft noise exposure associations, this finding is consistent with evidence of a homoeostatic BP response to recent changes in aircraft noise exposure, where resting BP returns to pre-existing levels unrelated to aircraft noise exposure. The public health implication of this finding appears to be benign.
495

Water for weststate, U.S.A. the association in the politics of water resource development.

Eiselein, E. B. January 1969 (has links) (PDF)
Thesis (Ph. D. - Anthropology)--University of Arizona. / Includes bibliographical references.
496

Blood pressure reduction following the accumulation of short physical activity sessions versus a continuous physical activity session in prehypertension

Park, Saejong. January 2006 (has links)
Thesis (Ph. D.)--Indiana University, 2006. / Includes bibliographical references. Also available online (PDF file) by a subscription to the set or by purchasing the individual file.
497

Blood pressure reduction following the accumulation of short physical activity sessions versus a continuous physical activity session in prehypertension

Park, Saejong. January 2006 (has links)
Thesis (Ph. D.)--Indiana University, 2006. / Includes bibliographical references.
498

The interactions of pressure sensitive adhesive with paper surfaces

Zhao, Boxin. Pelton, Robert H. January 2004 (has links)
Thesis (Ph.D.)--McMaster University, 2004. / Supervisor: Robert Pelton. Includes bibliographical references.
499

New well testing applications of the pressure derivative /

Onur, Mustafa. January 1989 (has links)
Thesis (Ph.D.)--University of Tulsa, 1989.
500

Two-phase pressure drop and holdup in flows through large diameter vertical tubing /

Güler-Quadir, Nihal. January 1900 (has links)
Thesis (Ph.D.)--University of Tulsa, 1991. / Bibliography: leaves 172-174.

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