O presente trabalho estuda a degradação fotocatalítica da nicotina em solução aquosa, um alcaloide altamente tóxico que tem sido detectado em efluentes, águas subterrâneas e água mineral. Os experimentos foram realizados em um reator batelada sob irradiação ultravioleta, tendo sido avaliadas três principais variáveis: concentração inicial do contaminante, concentração de catalisador e pH inicial da solução. Foram realizados dois planejamentos de experimentos para os catalisadores comerciais ZnO e TiO2, com o objetivo de encontrar a melhor condição para promover a degradação da nicotina em água. Outros catalisadores, preparados a partir de resíduos industriais e laboratoriais, foram testados nas condições otimizadas. O método analítico empregado para quantificar a nicotina nas amostras foi a cromatografia líquida de alta eficiência, o que permitiu registrar a formação de intermediários e subprodutos de reação. Os resultados experimentais demostraram que a degradação da nicotina por fotocatálise heterogênea é um processo bastante eficiente. Em ambos os planejamentos, o pH foi a variável que exerceu o maior efeito sobre a degradação, sendo este fortemente positivo. Já a concentração inicial de nicotina exerceu efeito negativo sobre a resposta e a concentração de catalisador em suspensão exibiu um ponto ótimo, que correspondeu a 0,91 g.L-1 para o ZnO, e 1,20 g.L-1 para o TiO2. Ensaios foram realizados nas condições otimizadas encontradas, onde cerca de 98% da molécula foi degradada utilizando ZnO em suspensão e 88% empregando TiO2, em uma hora de reação. A degradação fotocatalítica da nicotina demonstrou seguir uma cinética de pseudoprimeira ordem dentro do tempo de reação de 60 minutos, para os dois catalisadores comerciais. Entre os catalisadores não convencionais que foram testados, aquele que demonstrou o maior percentual de degradação foi obtido a partir de resíduo de uma indústria petroquímica, cerca de 43%. / The present work studies the photocatalytic degradation of nicotine in aqueous solution. This alkaloid is highly toxic and it has been detected in wastewater, groundwater and mineral water. The experiments were performed in a batch reactor under ultraviolet radiation. Three main variables of process were evaluated: initial concentration of pollutant, catalyst concentration and initial pH of the solution. Two experimental designs were performed for commercial catalysts ZnO and TiO2. The purpose was to find the best condition to promote the nicotine degradation in water. Other catalysts prepared from industrial and laboratory waste were tested under the optimized conditions. Analytical method used to quantify nicotine and its degradation products in all samples was high performance liquid chromatography. Experimental results showed that nicotine degradation by heterogeneous photocatalysis is a very efficient process. In both designs, initial pH was the most significant variable which has a strong positive effect. Initial nicotine concentration showed a negative effect, and catalyst concentration exhibited an optimal value for both commercial catalysts: 0,91 g.L-1 using ZnO, and 1,20 g.L-1 with TiO2. At the best conditions, about 98% of the molecule was degraded using ZnO and 88% with TiO2. Photocatalytic nicotine degradation followed a pseudo first order kinetic until 60 minutes of reaction for both commercial catalysts. Among the non-conventional catalysts tested, the one prepared from a petrochemical industry residue exhibited the highest photocatalytic degradation, about 43%.

Harvesting heads are an essential part of today’s forestry industry, enabling a high rate of tree felling from a single operator. Requirements for the forestry machine they are attached to are strongly linked to the weight of the harvesting head, providing an incentive to make the heads as light as possible. This can be done in various ways, of which one is switching the material to one that is lighter.This thesis examined the feasibility of producing the frame of a harvesting head in carbon fiber reinforced polymer. This was done through a redesign approach in several phases. The design and requirements of the existing harvesting head were detailed, the strengths and weaknesses of the material were studied, and topology optimization was utilized as a tool for better understanding the load paths and possible material placement. Concepts aimed at enabling production and use of the new frame while keeping features necessary for component attachment and function was then generated.The results showed a frame made largely from carbon fiber reinforced polymer, but with elements of steel, and with a total weight reduction of 45% compared to the original design. The conclusions of the thesis, within the established delimitations, is that a frame from this material is possible but complex to produce.

Hydrocolloid stabilizers are commonly used in ice cream formulations to provide body and reduce ice crystal growth during storage. We conducted a retail survey of 65 different vanilla ice cream brands and found the majority of manufacturers primarily use 1 or more of 4 different hydrocolloid sources: guar gum, carrageenan, locust and carob bean gum, or cellulose gum or gel. However, many consumers view hydrocolloids as unnatural, and the presence of hydrocolloids on an ingredient declaration may negatively affect purchase intent. Our survey of 705 consumers showed significant differences in purchase intent for vanilla ice cream, based on ingredient declarations containing different hydrocolloid stabilizers. A response surface central composite design was used to optimize ice cream stability using combinations of tapioca flour, carob bean gum, and citrus fiber, 3 consumer-preferred hydrocolloid stabilizers. Instrumental evaluations considered the dependent variables mix viscosity, ice cream hardness and toughness, melt-rate, and ice crystal size. A trained sensory panel also rated iciness, melt-rate, ease of breakdown in the mouth, and vanilla intensity. Each of the dependent variables from the trained panel and instrumental analysis were measured before and after a 3-week accelerated temperature cycling test. A regression analysis of the central composite design data combined instrumental and trained-panel results to compute a response surface based on the regression equation of each attribute. Using the response surface, 3 different optimized mix formulations were determined. The 3 different mixes were optimized using: 1) all dependent variables evaluated, 2) only sensory iciness scores, and 3) ice crystal size only. An untrained consumer panel evaluated samples before and after temperature cycling test, and rated vanilla ice creams prepared from all 3 optimized mixes against a control ice cream, prepared with a natural commercial stabilizer blend. The uncycled products prepared using optimized stabilizer blend were at statistical parity with the control product for overall acceptance, purchase likelihood, preference, sweetness and vanilla intensity, rate of melting in the mouth, texture and hardness. One or more of the optimized products were rated significantly better than the control for creaminess and texture. For products subjected to temperature cycling, 1 or more of the optimized products were rated significantly better than control for all attributes except sweetness and vanilla flavor intensity. This research indicates that more consumer-preferred options for ice cream stabilization are available to the ice cream industry, with performance and sensory results equal to other commercial hydrocolloid stabilizer blends.

Aortic stenosis is a serious cardiovascular disease that requires urgent attention and surgical intervention. If not treated, aortic stenosis can result in heart attack or cardiac arrest. Transcatheter Aortic Valve Replacement is a surgical technique that is used to treat aortic stenosis. Like all heart surgery, the procedure is difficult to perform and may lead to life-threatening complications. It is therefore important for a surgeon to be able to plan and rehearse the surgery before the operation to minimise risk to the patient. A detailed study was carried out to develop a 3D-printed, improved surgical tool for patient-specific planning and rehearsal of a Transcatheter Aortic Valve Replacement procedure. With this new tool, a cardiologist will be able better to understand a specific patient’s heart geometry and practice the procedure in advance. Computer tomography images were processed using image segmentation software to identify the anatomy of a specific patient’s heart and the surrounding blood vessels. Using materials design concepts, a polymer composite was developed that is able to mimic the mechanical properties of aortic tissue. State-of-art multi-material 3D printing technology was then used to produce a replica aorta with a geometry that matched that of the patient. An artificial aortic valve, identical to the type used in the Transcatheter Aortic valve replacement procedure, was then fitted to the replica aorta and was shown, using a standard test, to be a good fit with no obvious leaks. / Aortastenos är en hjärtsjukdom som får mycket uppmärksamhet och kräver kirurgi på grund av dess katastrofala komplikationer. Den allvarligaste komplikationen av aortastenos är hjärtinfarkt och resulterande hjärtstopp. Transcatheter Aortic Valve Replacement är en kardiovaskulär intervention som erbjuds för patienter med aortastenos. Denna typ av hjärtkirurgi är komplex och kan orsaka livshotande situationer för patienten om något går snett under operationen. Det är därför viktigt för kirurgen att kunna planera ingreppet innan han eller hon utför själva operationen för att minimera fara för patienten. Denna detaljerade studie ämnar utveckla och förbättra det kirurgiska verktyget för preoperativ planering av Transcatheter Aortic Valve Replacement genom 3D- tryckning. Forskningsarbetet kommer att ge kardiologer ett nytt sätt att förstå patientens hjärta i detalj och ett ökat förtroende för att träna på ingreppet på förhand. Datortomografibilder behandlades med hjälp av en bildsegmentationsprogramvara för att kunna skapa en anatomiskt korrekt kopia av patientens hjärta och tillhörande kärl. Genom att applicera material-vetenskapslära kan ett nytt kompositmaterial utvecklas med exakt samma mekaniska egenskaper som naturlig aortavävnad. Den mest moderna 3D-trycktekniken användes sedan för att producera en patientspecifik aorta. En artificiell aortaklaff placerades i den nyproducerade aortamodellen och tester visade en perfekt matchning utan läckage.

In this project, the scan strategy of selective laser melting (SLM) for thin walled structures was investigated by changing laser parameters and tool path. Producing thin walled structures is difficult due to defects such as warpage and porosity. A layer on the SLM 125 consists of hatch volume, fill contours, and borders, however, for thin walls, hatch volume can become unavailable, resulting in a solely border/fill contour laser tool path. Three central composite designs (CCD) were created to optimize the laser parameters of borders to minimize leakage rate and porosity. The two factors changed were border laser power and scanning speed. The center points of the CCDs were 0.24 J/mm, 0.20 J/mm, and 0.16 J/mm, respectively. This border linear energy density value was calculated by (border laser power / border scanning speed). A machined aluminum fixture was designed and assembled with pneumatics to perform a pressure drop leakage test. Additionally, micrographs of 500μm and 200μm wall thicknesses were analyzed to study between and within layers as well as melt pool dimensions. In the 200μm thick samples, there was delamination and insufficient overlap in border only prints. For border only prints, a lower border linear energy density is recommended, similar to Cal Poly’s hatch volume optimized parameters of 0.15 J/mm.

This paper evaluates the effective width of composite steel beams with precast hollowcore slabs numerically using the finite element method. A parametric study, carried out on 27 beams with different steel cross sections, hollowcore unit depths and spans, is presented. The effective width of the slab is predicted for both the elastic and plastic ranges. 8-node three-dimensional solid elements are used to model the composite beam components. The material non-linearity of all the components is taken into consideration. The non-linear load-slip characteristics of the headed shear stud connectors are included in the analysis. The moment-deflection behaviour of the composite beams, the ultimate moment capacity and the modes of failure are also presented. Finally, the ultimate moment capacity of the beams evaluated using the present FE analysis was compared with the results calculated using the rigid – plastic method.

Yes / This paper investigates the coupled effect of functionalized multiwall carbon nanotubes (MWCNTs-COOH), nanomontmorillonite (NM), and sodium dodecyl benzene sulfonate (SDBS) anionic surfactant on compressive and flexural strengths of cement paste. The response surface methodology (RSM) was used to optimize the content of the two nanomaterials and surfactant, and to analyze the effect of their interactions on mechanical properties and microstructural characteristics of the paste. Test results indicate that the simultaneous use of NM and MWCNT can lead to 30% gain in compressive strength and 40% increase in flexural strength. Using analysis of variance, it was possible to predict the optimal weight percentage of nanomaterials. Atomic Force Microscope observations showed that the use of NM and MWCNT can reduce the surface roughness of cement paste and refine porosity, thus reducing the risk of cracking at the cement matrix and improving the homogeneity of the microstructure.

Within the home environment there exits a host of digital color imaging (DCI) system configurations. The combination of devices and software at the consumer's desktop with devices and services at a remote location (e.g., Print at Kodak), creates a complex interaction of device, contextual, and observer characteristics. In particular, the cathode-ray tube (CRT) display has the potential to influence consumers' perceptions of image quality and their subsequent image manipulation activities. Depending on the inherent color bias and apparent contrast of the CRT, extensive image manipulation may occur, significantly altering the digital values of the image. Output generated by a remote printer will reflect any image manipulation undertaken by the consumer. If manipulation was extensive, what the consumer receives from a remote printer will appear quite different from the softcopy version and thus, may be deemed unacceptable. This research was designed to address the softcopy-hardcopy matching issues that arise from the home DCI system configuration just described. The primary study examined how the CRT display influenced perceived color quality of photographs generated at two points in a DCI system; on-screen photographs (softcopy) and photographic quality prints (hardcopy). CRT gamma, color temperature, and excitation purity were manipulated using an orthogonal, blocked, central composite design. Twenty-two Eastman Kodak Company employees viewed 6 photographs under each of the 15 CRT conditions. Participants rated the color quality of each softcopy photograph, then were given an opportunity to edit color balance, brightness, and contrast for each photograph. The edited photos were printed and rated once again for color quality and acceptability. Results indicated that monitor calibration influenced perceived softcopy color quality, softcopy editing behavior, and subsequent perceived hardcopy color quality. Perception of softcopy color quality ratings was determined predominantly by the CRT gamma level. Participants responded to CRT color balance differences through their editing behavior. In some cases, edits were large enough to significantly and negatively impact perceived hardcopy color quality. Gamma in particular, was the most significant predictor of hardcopy color quality ratings and rejection rates. Additional differences were observed between first- and third-party photographs. Results from this research may be applied to the development of monitor calibration tools, scene balancing algorithms, and software, for the purpose of accommodating consumer image manipulation behavior, in the context of the home DCI system presented herein. / Ph. D.

This manuscrit is a compact presentation of my research done between 1993 and 2008 and which concerns the global optimization of mechanical systems. General and specialized global optimization algorithms are presented. With respect to previously published work, an updated presentation of my work on composite optimization is given.

This thesis deals with the possibility of applying the method of Design of Experiments (DoE) on specific data. In the first chapter of theoretical part, this method is described in detail. The basic principles and guidelines for the design of the experiment are written there. In the next two chapters, factorial design of the experiment and response surface design are described. The latter one includes a central composite design and Box-Behnken design. The following chapter contains practical part, which focuses on modelling firing range of ball from a catapult using the above three types of experimental design. In this work, the models are analysed together with their different characteristics. Their comparison is made by using prediction and confidence intervals and by response optimizing. The last part of the thesis comprises overall evaluation.