Analytical three-dimensional temperature field in the liquid and heat-affected zones and prediction of the three-dimensional fusion zone shape around the keyhole produced by a moving high-intensity beam are provided. Determination of the fusion zone shapes is of fundamental and practical importance to understand properties and microstructures of joints. In this work, the keyhole is idealized by a paraboloid of revolution in a finite workpiece subject to an incident flux of a Gaussian distribution.Introducing analytical solutions of three-dimensional analytical temperature field, the dimensionless width, leading and rear edges, and depth of the fusion zone are analytically found to be a function of the dimensionless parameters governing beam power per unit penetration, location of the workpiece surface and shape of the keyhole. The dimensionless parameters governing the keyhole shape can be evaluated from a force balance at the keyhole base. The results show the effects of welding parameters, such as the dimensionless beam power, Peclet number, cavity opening radius, Biot number, thickness of workpiece, and the parameter approximating convection, on the shape of the fusion zone and the temperature of keyhole surface. A significant difference in the fusion zone shapes predicted between the line-source solution and this work indicates the strong effects of three-dimensional heat transfer. Agreement between the prediction from this work and available experimental data is achieved.

Univ., Diss.--Bremen, 2003. / Enth. außerdem 4 Originalpublikationen.

Leakage of stored bulk phase CO₂ is of particular risk to sequestration in deep saline aquifers due to the fact that when injected into typical saline aquifers, the CO₂ rich gas phase has lesser density than the aqueous phase resulting in buoyancy driven flow of the fluids. As the CO₂ migrates upward, the security of its storage depends upon the trapping mechanisms that counteract the migration. While there are a variety of trapping mechanisms the mechanism serving as motivation for this research is local capillary trapping. Local capillary trapping occurs during buoyancy-driven migration of bulk phase CO₂ within a saline aquifer (Saadatpoor, 2009). When the rising CO₂ plume encounters a region where capillary entry pressure is locally larger than average, CO₂ accumulates beneath the region. While research is continued by means of numerical simulation, research at the bench scale is needed to validate the conclusions made from simulation work. Presented is the development of a bench scale experiment whose objective is to assess local capillary trapping. The initial step in accomplishing this objective is to understand the fluid dynamics of CO₂ and brine in a saline aquifer which is categorized as two phase immiscible buoyancy driven displacement. Parameters influencing this displacement include density, viscosity, wettability and heterogeneity. A bench scale environment created to be analogous to CO₂ and brine in a saline aquifer is created in a quasi-two dimensional experimental apparatus, which allows for observation of plume migration at ambient conditions. A fluid pair analogous to supercritical CO₂ and brine is developed to mimic the density and viscosity relationship found at pressure and temperature typical of storage aquifers. The influences of viscosity ratio, density differences, porous medium wettability and heterogeneity are observed in series of experimental sequences. Three different fluid pairs with different viscosity ratios and density differences are used to assess density and viscosity influences. Porous media of varying grain size and wettability are used to assess the influence of heterogeneity and wettability. Results are qualitatively consistent with theoretical results and those from previous works. / text

Rationale: The pathophysiologic differences between classic asthma (CA), cough variant asthma (CVA), and methacholine (MCh)-induced cough but normal airway sensitivity (COUGH) are poorly understood and may relate to differences in small airway function. We hypothesized that the bronchodilating and bronchoprotective effects of DIs are: (a) absent or impaired in individuals with CA; (b) impaired in individuals with CVA; and (c) preserved in those with COUGH. Purpose: To compare the effect of DIs in individuals with CA, CVA and COUGH using high-dose methacholine (MCh). Methods: Individuals aged 18-65 years with CA, or suspected CVA attended 3 visits. On visit 1, subjects performed body plethysmography and high-dose MCh testing to a maximum change (Δ) in FEV1 of 50% from baseline (MAX). On visits 2 and 3, subjects performed one of two modified single-dose MCh challenge tests with or without DIs prior to MCh administration. Partial and maximal-flow volume curves (used to calculated a DI index), impulse oscillometry (IOS) measurements and breathlessness (Borg scale) were recorded at baseline and at each dose of MCh. Lung volumes were measured by body plethysmography at baseline and MAX. Responses from baseline to a 20% decline in FEV1 (PC20) or MAX, and between visits with or without DIs were compared using paired t-tests. Between group differences were assessed by analysis of variance. Results: 19 subjects (14 female; 45.1±13.1 years (MEAN±SD)) completed the protocol (n=8 CA, n=7 CVA, and n=4 COUGH). At the dose nearest to PC20, the DI index was positive in all 3 groups, indicating preserved bronchodilation (CA: 0.88±0.67; CVA: 0.33±0.39; COUGH: 0.016±0.46; P=.0.076). There were no significant differences in: the Δs in spirometry, lung volumes, airway resistance, IOS measurements, closing indices, the DI index, or dyspnea when the single dose of MCh was preceded either by five DIs or by DI avoidance in CVA and COUGH. DIs in CA resulted in greater Δs in mid-to-late flows. Conclusion: The bronchodilating effect of DIs is preserved in CA, CVA and COUGH. The bronchoprotective effect may fall along a continuum. A larger study including subjects with more severe CA is required to definitively test the hypotheses. / Thesis (Master, Physiology) -- Queen's University, 2014-06-28 11:23:29.814

No description available.

The work described in this thesis is concerned with the behaviour, analysis and design of reinforced concrete beams. A brief historical review of the methods of analysis on deep beams is given. The current major codes of practice and design manuals associated with reinforced concrete deep beams are reviewed. This study has been useful in identifying the limitations of the current design documents on the subject of deep beams. Because of the acute shortage of information regarding buckling, web-opening and combined loading, three test programmes are performed to provide experimental evidence on these topics. Their behaviour is examined in terms crack developments, crack patterns, modes of failure, in-plane and lateral displacements, ultimate loads, strains and stresses. The ultimate buckling strength of the slender deep beams without web-openings are analysed using the methods described in the CIRIA Guide (1977). Adopting the same methods in the guide, an attempt has been made to analyse the buckling strength of deep beams with web-openings. Based on the structural idealization of Kong et al (1973), a modified approach is proposed for the ultimate shear strength of deep beams with web-openings. In addition, the CIRIA ultimate shear interaction equation for deep beams under combined top and bottom loadings is studied and an equation is proposed for the uniformly distributed loading cases. Finally, based upon these findings, some design recommendations are given.

Thesis (Ph.D.)--York University, 2006. Graduate Programme in Physics and Astronomy. / Typescript. Includes bibliographical references (leaves 161-166). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR29528

Thesis (Ph. D.)--University of Wisconsin--Madison, 1955. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

"January 1992." / "Technical report." "Funding was provided by the Office of Naval Research through Contract no. N00014-90-C-0098." Includes bibliographical references (p. 37-38).

Thesis--Oregon State University. / Photocopy of typescript. Ann Arbor, Mich. : Xerox University Microfilms, 1976. -- 21 cm. Bibliography: leaves 126-129.