SpinChem AB's rotating bed reactor (RBR) is a small cylindrical centrifuge that allowsfor eective convective reactions between chemical substances. The aim of my master'sdissertation was to develop a measurement system that could estimate the uid velocity insidethe RBR. This report covers a quick pre-study of dierent uid measurement methods,details how we designed and constructed the system using integrated circuits and other electroniccomponents, and illustrates calibration results and nal velocity measurements. Thesystem design was based on the architecture of hot-wire constant temperature anemometry(CTA), a technique that measures the uid velocity over a heated metal wire. The resultsof this project is the measurement system itself, and the calibration and velocity measurementsgathered from experimentation. Two issues we encountered was that the calibrationprocess resulted in an overestimation of the velocity in the order of 4000 cm/s, and thatthe response to changes in velocity rates was quite slow. However, a slight tuning of thetwo calibration constants A0 & B0 smoothed the velocity estimation out to 40 cm/s, whichis more what we would expect. This illustrated how sensitive the results were to errors inthe calibration. Further investigation of the slow response, and a more stringently executedcalibration setup, could make the CTA a potential candidate for estimating the uid velocityinside the RBR.

This study involves analyses and experiments of magnesium¡¦s hot extrusion of thin sheets and tubes. At first, hot compression tests are conducted to obtain the magnesium¡¦s plastic flow stresses in high tempearatures, which will be used in the finite element analysis. In the FE simulations of thin sheet extrusion, the flow pattern of the magnesium billet within the die, the temperature history at die exit and the elastic deformation of the die is analyzed. Sound and good thin sheets are obtained by appropriate die design, initial billet temperature and extrusion velocity¡¦s control. The goal of constant temperature extrusion is expected to achieved by controlling the extrusion velocity which will influences the billet temperature at die exit. In FE simulations of thin tube extrusion, the flow pattern of the magnesium billet within the port-holes, welding chamber and die bearing is analyzed. The elastic deformation of the die is dicussed. Extrusion of sound thin tubes is achieved by appropriate extrusion conditions. Finally, hot extrusion experiments are conducted and the experimental values of the extrusion load and dimensions of the products are compared with the analytical values to verify the validity of the analytical models.

no / Small-scale heterogeneity of biogenic carbonate elemental composition can be a significant source of error in the accurate use of element/Ca ratios as geochemical proxies. In this study ion microprobe (SIMS) profiles showed significant small-scale variability of Mg/Ca, Sr/Ca and Mn/Ca ratios in new shell calcite of the marine bivalves Pecten maximus and Mytilus edulis that was precipitated during a constant-temperature culturing experiment. Elevated Mg/Ca, Sr/Ca and Mn/Ca ratios were found to be associated with the deposition of elaborate shell features, i.e. a shell surface stria in P. maximus and surface shell disturbance marks in both species, the latter a common occurrence in bivalve shells. In both species the observed small-scale elemental heterogeneity most likely was not controlled by variable transport of ions to the extra-pallial fluid, but by factors such as the influence of shell organic content and/or crystal size and orientation, the latter reflecting conditions at the shell crystalsolution interface. In the mid and innermost regions of the P. maximus shell the lack of significant small-scale variation of Mg/Ca ratios, which is consistent with growth at constant temperature, suggest a potential application as a palaeotemperature proxy. Cross-growth band element/Ca ratio profiles in the interior of bivalve shells may provide more promising palaeo-environmental tools than sampling from the outer region of bivalve shells.

No description available.

This thesis presents a detailed, two-dimensional analysis of the performance of multi-element guard-heated hot-film wall shear stress microsensors for turbulent flows. Previous studies of conventional, single-element sensors show that a significant portion of heat generated in the hot-film travels through the substrate before reaching the fluid, causing spectral and phase errors in the wall shear stress signal and drastically reducing the spatial resolution of the sensor. Earlier attempts to reduce these errors have focused on reducing the effective thermal conductivity of the substrate. New guard-heated microsensor designs proposed to overcome the severe deficiencies of the conventional design are investigated in this thesis. Guard-heaters remove the errors associated with substrate heat conduction, by forcing zero temperature gradient at the edges and bottom face of the hot-film, and hence, block the indirect heat transfer to the flow. Air and water flow over the sensors are studied numerically to investigate design, performance and signal strength of the guard-heated sensors. Our results show, particularly for measurements in low-conductivity fluids such as air, that edge guard-heating needs to be supplemented by a sub-surface guard-heater, to make substrate conduction errors negligible. With this two-plane guard-heating, a strong non-linearity in the standard single-element designs can be corrected, and spectral and phase errors arising from substrate conduction can be eliminated. / Graduate / 0548 / etrati@uvic.ca

Simulations of particle systems at constant temperature may be used to estimate several of the system’s physical properties, and some require integration over very long time to be accurate. To achieve sufficient accuracy in finite time the choice of numerical scheme is important and we suggest to use the symplectic Euler method combined with a step in an Ornstein-Uhlenbeck process. This scheme is computationally very cheap and is often used in applications of molecular dynamics. This thesis strives to motivate the usage of the scheme due to the lack of theoretical results and comparisons to alternative methods. We conduct three numerical experiments to evaluate the scheme. The design of each experiment aims to expose weaknesses or strengths of the method. For both model problems and more realistic experiments are the results positive in favor of the method; the symplectic Euler method combined with an Ornstein- Uhlenbeck step does perform well over long times. / Simuleringar av partikelsystem vid konstant temperatur kan användas för att uppskatta flera av systemets fysiska egenskaper. Vissa klasser av egenskaper kräver integration över väldigt lång tid för att uppnå hög noggrannhet och för att uppnå detta i ändlig tid är valet av numerisk metod viktigt. Vi föreslår att använda den symplektiska Euler-metoden i kombination med ett implicit steg i en Ornstein-Uhlenbeck-process. Detta stegschema kräver låg beräkning jämfört med andra scheman och används redan i olika applikationer av molekyldynamik. Detta examensarbete eftersträvar att än mer motivera användandet av schemat, eftersom teoretiska resultat som stödjer metoder är få, och avsaknaden av tidigare liknande studier är betydlig. Vi genomför tre numeriska experiment för att pröva schemat. Under utformningen av experimenten har vi försökt att inkorporera olika fenomen som kan orsaka svårigheter för metoden för att exponera svagheter eller styrkor hos den. För båda modellproblem och för ett mer realistiskt experiment är resultaten positiva till schemats fördel; metoden att kombinera ett symplektisk Euler-steg med ett steg i Ornstein-Uhlenbeck-processen presterar bra över lång tid.

The master's thesis is devoted to the design development, the calculation of the thermal and gas-dynamic modes of operation of a furnace furnace of the baraban type, designed to heat metal products before quenching. In the course of work, heat engineering calculations were carried out for a new drum-type furnace design, the heat balance of the furnace was obtained, and computer simulation of gas dynamics in the working space of the chamber furnace was carried out in the Ansys Fluent software module. The results of the work can be used in the performance of research and development work at metallurgical enterprises, as well as in the educational process for training bachelors and undergraduates in the direction of “Metallurgy” (bachelor’s and master’s level). / Магистерская диссертация посвящена разработке конструкции, расчету теплового и газодинамического режимов работы камерной печи барабанного типа, предназначенной для нагрева металлических изделий перед закалкой. В ходе работы проведены теплотехнические расчеты для новой конструкции печи барабанного типа, получен тепловой баланс печи, в программном модуле Ansys Fluent проведено компьютерное моделирование газодинамики в рабочем пространстве камерной печи. Результаты работы могут быть использованы при выполнении научно-исследовательских работ на металлургических предприятиях, а также в учебном процессе для обучения бакалавров и магистрантов по направлению «Металлургия» (уровень бакалавриата и магистратуры).