Most heat transfer tubes are designed for either fully uniform wall temperature or fully uniform wall heat flux boundary conditions under forced convection. Several applications, including but not limited to the solar collectors of renewable energy systems, do however operate with non-uniform boundary conditions. Limited research has been conducted on non-uniform wall heat flux heat transfer coefficients in circular tubes, especially for mixed convection conditions. Such works are normally numerical in nature and little experimental work is available. In this experimental investigation the effects of the circumferential heat flux distribution and heat flux intensity on the single phase (liquid) internal heat transfer coefficient were considered for a horizontal circular tube. Focus was placed on the laminar flow regime of water within a stainless steel tube with an inner diameter of 27.8 mm and a length to diameter ratio of 72. Different outer wall heat flux conditions, including fully uniform and partially uniform heat fluxes were studied for Reynolds numbers ranging from 650 to 2 600 and a Prandtl number range of 4 to 7. The heat flux conditions included 360˚ (uniform) heating, lower 180˚ heating, upper 180˚ heating, 180˚ left and right hemispherical heating, lower 90˚ heating, upper 90˚ heating and slanted 180˚ heating. Depending on the angle span of the heating, local heat fluxes of 6 631 W/m2 , 4 421 W/m2 , 3 316 W/m2 , 2 210 W/m2 and 1 658 W/m2 were applied. Results indicate that the local and average steady state Nusselt numbers are greatly influenced by the applied heat flux position and intensity. Highest average heat transfer coefficients were achieved for case where the applied heat flux was positioned on the lower half (in terms of gravity) of the tubes circumference, while the lowest heat transfer coefficients were achieved when the heating was applied to the upper half of the tube. Variations in the heat transfer coefficient were found to be due to the secondary buoyancy induced flow effect. The relative thermal performance of the different heating scenarios where characterised and described by means of newly developed heat transfer coefficient correlations for fully uniform heating, lower 180° heating, and upper 180° heating. / Dissertation (MEng)--University of Pretoria, 2018. / Mechanical and Aeronautical Engineering / MEng / Unrestricted

Bibliography: pages 90-94. / Ordered spaces were introduced by Leopoldo Nachbin [1948 a, b, c, 1950, 1965]. We will be primarily concerned with completely regular ordered spaces, because they are precisely those ordered spaces which admit quasi-uniform structures. A recent and convenient study of these spaces is in the book by P. Fletcher and W.F. Lindgren [1982]. In this thesis we consider functorial quasi-uniformities over (partially) ordered spaces. The functorial methods which we use were developed by Brummer [1971, 1977, 1979, 1982] and Brummer and Hager [1984, 1987] in the context of functorial uniformities over completely regular topological spaces, and of functorial quasi-uniformities over pairwise. completely regular bitopological spaces. We obtain results which are to a large extent analogous to results in those papers. We also introduce some functors which relate our functorial quasi-uniformities to the structures studied by Brummer and others (e.g. Salbany [1984]).

History can be experiences in many ways, it can be taught in schools, it can be studied by archaeologists in the field. It can also be done by reading historical fiction, and it can be experienced through walking a mile in an historical person’s shoes. Literally walking. This thesis focuses on the experiences of wearing a Legionnaire uniform during the historically inspired larp Legion, made by the company Rolling, in the czech republic. The thesis explores the physical experience of wearing a uniform in harsh winter terrain during this larp as well the emotional process a person goes through while in uniform during the larp The main questions of issue were:  * How does modern humans experience this kind of historical uniform in winter terrain? * What does the uniform do with the person wearing it?  The first question focused on the physical part of wearing the uniform, and the second question focused more on the emotional part of wearing it.  The data was collected by asking larpers who had attended the larp to fill out a survey containing questions about their experiences.  The analysis was done using Actor Network Theory, a theory which made it possible to see connections between the larpers, the terrain, the temperature, and the uniform itself. Maslow’s hierarchy of needs was also used to further analyse the data.  The results of this study show that there are many clusters of actors that play an important part of the experiences of wearing the uniform. The temperature was an important actor, as well as how the uniform erased differences between individuals making comradery a major part of the experience. Emotions of inner strength, confidence and calm were also important parts of what the larpers experiences when wearing the uniform.

Mississippi growers often have issues with corn seedling establishment due to saturated and cool soils, which can reduce productivity. Our first objective was to quantify yield reduction associated with variable emergence. Four patterns simulating various extent of affected plants and four different emergence delays were hand planted uniformly at a standard population. Plants were closely monitored to document emergence variability. Growth stages were measured three separate ways to identify the best field method to characterize stand variability. Data suggest there were yield disadvantages associated with emergence variability. Another objective was to evaluate practical replanting methods for Mid-South corn growers. Treatments included four populations planted at a normal time and replant interval. Two different series of treatments were imposed to evaluate the productivity of intra-planting seed in a partial stand. Corn grain yield was 11% greater when replanting in a clean seedbed, compared to all intra-planted treatments.

Syftet med mitt examensarbete är att undersöka ifall införandet av en skoluniform skulle få bort kläders betydelse i dagens skola. Till min hjälp har jag använt mig av fem frågeställningar som alla handlar om kläders betydelse inom skolan. Den metod jag använt är kvalitativ, både observation och intervju. Jag valde, slumpmässigt ut åtta elever i årskurs 9 för intervju. Resultatet av både observationen och intervjuerna vittnar om att kläder har en stark betydelse för vem man är. Det är viktigt att se bra ut och att ha snygga kläder. De som har samma kläder på sig i flera dagar, eller som inte har fina kläder, kan fara illa i form av mobbning och utanförskap. Förvånansvärt många tyckte att införandet av en skoluniform hade varit bra, sett ur ett statusperspektiv.

<p> A general, consistent, nonlinear theory for open thin-walled elastic beams is presented. The theory takes into account geometric nonlinearities caused by large rotation of the cross section of the beam. The nonlinear differential equations of deformation and response are derived by means of application of Hamilton's principle. It is found that the set of equations reduces to the results obtained by Cullimore and Gregory in the special cases of large uniform torsion of thin-walled members. A solution of a thin-walled beam, subjected to large non-uniform torsional deformation due to application of torques at the ends, is obtained. Comparison is made on the torque - rotation characteristics of a thin-walled beam subjected to large uniform torsion and large non-uniform torsion to show the effect of end constraint from warping.</p> <p> A set of nonlinear equations to study the stability of a thin-walled beam of open cross section, under axial loading (spatial stability) and lateral loading (lateral stability), is presented. Using the derived equations, the dynamic stability of thin-walled beams of symmetrical and monosymmetrical cross sections subjected to axial loads, is investigated. The regions of parametric instability, the steady state amplitudes of oscillations, once parametric instability takes place, and the non-steady state solutions, to show the growth of the parametric oscillations, are carried out.</p> <p> The effect of viscous damping on the steady state amplitude and the growth behaviour of the parametrically excited oscillations is shown. The dynamic stability of a thin-walled beam of symmetrical I section and a monosymmetrical split ring section are worked out in detail as examples.</p> / Thesis / Doctor of Philosophy (PhD)

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