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In regions with cold climates, a layer of ice often forms on vehicle windshields, whichobstructs the driver’s view. To address this issue, vehicles are equipped with internal defrosters. However, at Scania, the evaluation of defroster design performancecurrently relies on time-consuming and costly physical testing. A more effectiveapproach would be to employ numerical techniques to accurately forecast defrostingpatterns. This would offer valuable insights for analyzing the defroster’s performanceduring the design phase.The objective of this thesis is to develop a methodology using the open-source CFDsoftware OpenFOAM to predict the performance of a vehicle’s defrosting system.This approach presents a quicker and more convenient way to design the systemcompared to conventional testing methods. Experimental results were obtained bymonitoring the defrosting process at regular intervals. However, uncertainties existedregarding boundary and ambient conditions as the experiments were not conductedto validate the CFD results. The temperature profile and mass flow rate at the inlet were unknown. The model’s geometry was pre-processed using ANSA, and thevolume mesh for the truck cabin was generated using the SnappyHexMesh utilityin OpenFOAM. Mesh verification demonstrated good quality, and the realizable k-εturbulence model was utilized. The Grid Convergence Index (GCI) was employedto compare different mesh sizes, ultimately achieving a converged mesh. The RKEmodel was found to be computationally efficient and suitable for defrosting simulations, producing similar results to the k-ω SST turbulence model.A time step study was conducted to determine an efficient time-step. Additionally,a temperature study was performed to address the uncertainty surrounding the inlet temperature. Various design points were examined, involving different heat-uptimes and maximum temperatures. The results indicated that a heat-up time of 600seconds and a maximum temperature of 308 Kelvin yielded similar outcomes to theexperiments. To address uncertainty regarding the inlet mass flow rate, a study wasconducted by varying the mass flow rate. Comparing the results with the experimental data, a mass flow rate of 450 kg/hr provided the most comparable defrostingperformance. The study also investigated the impact of the exterior domain anddetermined that removing it would lead to inaccurate defrosting predictions due to alack of heat transfer. Furthermore, a comparison of OpenFOAM and StarCCM+ forsteady-state solutions demonstrated satisfactory results in terms of turbulent kineticenergy and wall shear stress at the windshield. Attempts to optimize defrosting performance included optimizing the shape of the defroster vents. The effect of rotatingthe vents relative to the windshield surface on defrosting was assessed, but it wasconcluded that the angle had minimal impact on performance or the methodology isnot sensitive enough to differentiate the minor differences.In conclusion, this thesis presents an efficient methodology utilizing OpenFOAM topredict defrosting performance, encompassing complete windshield defrosting timeand ice melting rate. It holds potential for future defroster design processes. Furtherstudies could focus on alternative meshing methods to reduce computational costs.

<p>The present work relates to a new procedure, to perform temperature measurements with unprecedented accuracy. The new approach relies on a correction based on a two-wire probe thermocouple that enables a precise estimation of the conduction error. The difference between measured temperature by a thermocouple and total gas temperature for steady conditions can be decomposed into three main contributions: velocity error, conduction error and radiation error. Radiation error can be considered negligible for temperatures lower than 800K. The velocity error can be corrected using dedicated experimental calibrations to measure the recovery factor. However, the conduction error, remains an unresolved challenge in the aerospace and power-energy community. The proposed method includes a comprehensive correction with different options for the postprocessing. The method has been demonstrated using high-fidelity aero-structural computational simulations.</p>

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<p>I put department up there as Biomedical Engineering. The full title should be: School of Biomedical Engineering.</p> / <p>The work presented in this thesis was focused on the surface modification of biomaterials with combinations of polyethylene glycol (PEG) and bioactive molecules (protein anticoagulants) for improved blood compatibility. Since the fate of biomaterials in contact with blood depends significantly on plasma protein-surface interactions, the objective of this work was to reduce non-specific protein adsorption using PEG and to promote specific protein interactions that could inhibit clot formation using protein anticoagulants as modifiers.</p> <p>Two anticoagulant molecules were used in this work: hirudin, a specific inhibitor of thrombin and corn trypsin inhibitor (CTI), a specific inhibitor of clotting factor XIIa. Gold, used as a model substrate, was modified with PEG and anticoagulant molecules using two methods referred to as sequential and direct. In the sequential method PEG was first immobilized on the surface and then the bioactive molecule was attached (conjugated) to the PEG. In the direct method, a PEG-bioactive molecule conjugate was first formed and then immobilized on the surface. Surfaces were characterized by contact angle, ellipsometry and x-ray photoelectron spectroscopy (XPS). Uptake of the bioactive molecules was measured by radiolabeling. Biointeraction studies included plasma protein adsorption, bioactivity assays using chromogenic substrates and clotting time assays. For PEG-hirudin and PEG-CTI surfaces (both direct and sequential) the protein resistance was similar to that of the PEG-alone surfaces. Despite having a lower density of bioactive molecule (both hirudin and CTI), the sequential surfaces showed superior bioactivity compared to the direct ones.</p> <p>To determine the optimal ratio of free PEG and bioactive molecule-PEG conjugate on the surface (best combination of protein resistance and bioactivity), PEG-CTI was immobilized on gold substrate with varying ratio of conjugated to free PEG using both direct and sequential methods. As the ratio increased, protein resistance was maintained while specific interactions (bioactivity) increased. The optimal composition appeared to be where all PEG molecules are conjugated to a CTI molecule.</p> <p>In the final part of this project, PEG and CTI were immobilized on polyurethane as a material with applicability to medical device construction. A sequential method was developed for this substrate. Comparison of the PEG-CTI surface with PEG only or CTI only surfaces indicated that the combination of PEG-CTI was effective both in reducing non-specific protein adsorption and promoting the specific interactions of CTI with its target plasma protein, factor XIIa. In fact, the presence of PEG improved CTI interactions with FXIIa compared with CTI only surfaces. Thus, sequential attachment of PEG and CTI may be effective for modifying polyurethane surfaces used in blood-contacting medical devices.</p> / Doctor of Philosophy (PhD)

Commercial viewing was measured by a conjugate arrangement for 1 female and 3 male participants. Reinforcing qualities were evaluated according to screen variations and ratings. Subjects changed the screen clarity via knob pressing either making the screen more or less transparent, translucent or opaque based on commercial interest. Results were conducive to participant attentiveness or indifference to commercial viewing. Experimenter was able to identify the commercials that grasped and maintained the participants' viewing behavior. Conceptually this conjugate arrangement could enhance eye tracking technology to improve marketing and advertising strategies. This experiment yield results that suggest a more concrete analysis of consumer response to visual stimuli that maintains attending.

京都大学 / 新制・課程博士 / 博士(薬学) / 甲第24563号 / 薬博第861号 / 新制||薬||243(附属図書館) / 京都大学大学院薬学研究科薬学専攻 / (主査)教授 髙倉 喜信, 教授 山下 富義, 教授 小野 正博 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM