The objective of this work is to develop mathematical models for predicting the thermal stability of commercial diagnostic assays. These assays are a product of the Point of Care division of Abbott laboratories, and are used for analyzing patient blood samples for specific substances. The accuracy of the results from these diagnostic tests relies on the activity of specific biological and/or chemical components of the sensors. Mathematical models that describe the stability of these active components are useful for supporting product shelf-life claims and for the design and implementation of accelerated testing protocols. In the thesis, the stability of two diagnostic assay systems of interest to Abbott Point of Care is investigated using mathematical modeling. For the first assay system investigated, the biosensor associated with the assay is identified as an important factor for product stability. A second-order dynamic model is developed to describe the thermal stability of this biosensor. The model corresponds to a reversible reaction followed by an irreversible reaction, with rate coefficients having Arrhenius temperature dependencies. The second-order dynamic model provides improved predictions relative to a first-order dynamic model, based on a comparison between model fits for two experimental datasets, and a comparison of predictive ability for a validation dataset. The second-order dynamic model is used to extend the concept of Mean Kinetic Temperature concept from the pharmaceutical industry to systems with higher-order dynamics. For the second assay system investigated, the calibration fluid is identified as a key factor in assay stability. A first-order model is developed to describe the stability of the analyte within the calibration fluid. The first-order model captures most of the trend present in the data from calibration fluid incubation experiments. Finally, model predictions are used to investigate the amount of change in assay response that can be attributed to changes in concentration of analyte in the calibration fluid (after storage at elevated temperatures). The results show that the changes observed in assay responses are consistent with the magnitude of changes in calibrant analyte concentrations predicted by the model. / Thesis (Master, Chemical Engineering) -- Queen's University, 2011-02-02 00:09:23.758

This thesis investigates the electrical and electrochemical properties and the long-term stability of anodes of the solid oxide fuel cell (SOFC). A model is suggested, which describes the impedance spectra of symmetrical anode cells. According to this, the series resistance in the spectra is caused by the resistance of the electrolyte (YSZ), ohmic parts of the anodes, which are described as porous electrodes, and by the partial contacting of the anodes. A major contribution to it is provided by the nickel matrix in the anodes. The high frequency relaxation in the spectra is assigned to the transfer reaction, the low frequency to a gas diffusion inhibition along the gas supply channels. The degradation of the symmetrical anode cells, which has been observed in long-term experiments, is ascribed to a degradation of the electrolyte material, of the transfer reaction, of the nickel matrix in the anodes and of the contact resistance between the anodes and the current collecting nickel grids. The degradation rate of the last two depends on the gas composition. A model for the observed behaviour in time is presented. / Diese Arbeit untersucht die elektrischen und elektrochemischen Eigenschaften und die Langzeitbeständigkeit der Anoden von Festoxid-Brennstoffzellen (SOFC). Ein Modell wird vorgestellt, mit dem die Impedanzspektren symmetrischer Anodenzellen beschrieben werden können. Demnach ist der Serienwiderstand in den Spektren verursacht durch den Widerstand des Elektrolyten (YSZ), ohmsche Anteile in den Anoden, die als poröse Elektroden beschrieben werden, und durch die partielle Kontaktierung der Anoden. Maßgebliche Beiträge liefert hier die Nickelmatrix in den Anoden. Die hochfrequente Relaxation in den Spektren wird der Durchtrittsreaktion, die niederfrequente einer Gasdiffusionshemmung entlang der Gasversorgungskanäle zugeordnet. Die in Langzeitversuchen beobachtete Degradation der symmetrischen Anondenzellen wird zurückgeführt auf eine Degradation des Elektrolytmaterials, der Durchtrittsreaktion, der Nickelmatrix in den Anoden und des Kontaktwiderstandes zwischen den Anoden und den stromabnehmenden Nickelnetzen. Die Degradation der beiden letzteren ist in ihrer Rate abhängig von der Gaszusammensetzung. Ein Modell für das beobachtete zeitliche Verhalten wird vorgestellt.

Tato práce se se zabývá návrhem kinematiky zavěšení kol obou náprav. Na základě analýz jízdních dat, multi-body simulací v softwaru Adams Car, simulací v Matlabu a analytických kalkulací v Mathcadu, je navržena řada změn s cílem zlepšit jízdní vlastnosti vozu Formule student, tyto změny jsou následně implementovány do CAD modelu vozu. Jednotlivé změny kinematiky náprav jsou provedeny na základě analýzy konkrétního problému, který se snaží řešit. Jednou z problematik je zástavbová náročnost systému odpružení a zavěšení zadních kol, zde je cílem snížit hmotnost, výšku těžiště a moment setrvačnosti. Další problematikou je geometrie předního kola, kde je cílem zlepšit využití pneumatik a snížit síly v řízení. Dále se práce zabývá simulacemi elastokinematiky zadní nápravy, součástí je také návrh měřícího zařízení. V poslední části je zkoumán vliv provedených změn i elastokinematiky na jízdní dynamiku vozu v ustálených stavech za pomocí MM metody simulované s modelem celého vozu v Adams Car a zpracované v Matlabu.