Dans cette thèse, deux problèmes complètement indépendants sont étudiés. Le premier sujet porte sur l'analyse mathématique d'un modèle simple de délamination de films minces et d'apparition de cloques. Le second sujet est une étude fine de l'équation des milieux poreux motivée par des problèmes d'intrusion saline. Dans le premier sujet de ce travail, nous considérons un modèle variationnel simple unidimensionnel décrivant la délamination de films minces sous l'effet d'un refroidissement. Nous caractérisons les minimiseurs globaux qui correspondent à trois types de films: non-délaminés, partiellement délaminés (appelés cloques) ou bien complètement délaminés. Deux paramètres jouent un rôle crucial dans un tel phénomène : la longueur du film et la température. Dans le plan de phase de ces deux derniers, nous classifions l'ensemble des minimiseurs. Comme conséquence de notre analyse, nous identifions explicitement les cloques les plus petites pour ce modèle. Dans le deuxième sujet, nous répondons d'abord à une question ouverte depuis longtemps concernant l'existence de nouvelles contractions pour l'équation de type milieux poreux. Pour m>0, nous nous sommes intéressés à des solutions positives de l'équation suivanteU_t=Delta U^m. Pour 0<m<2, nous présentons une nouvelle famille de contractions pour cette équation en toute dimension, ce qui induit une extension des propriétés de la contraction L^1. Notre contraction peut être considérée comme étant la quatrième contraction connue pour cette équation. Même pour le cas m=1, notre approche aboutit à des nouveaux résultats pour l'équation de la chaleur standard. Dans un second temps, nous avons traité le même problème mais en utilisant une approche différentielle différente basée sur les distances géodésiques. Cette approche originale et générale sert à fabriquer des familles de contractions pour des équations aux dérivées parielles non linéaires, d'évolutions ou stationnaires. Nous présentons dans ce cadre diverses applications. En particulier, nous traitons à nouveau l'équation des milieux poreux et l'équation doublement non linéaire / In this thesis, we study two completely independent problems. The first one focuses on a simple mathematical model of thin films delamination and blistering analysis. In the second one, we are interested in the study of the porous medium equation motivated by seawater intrusion problems. In the first part of this work, we consider a simple one-dimensional variational model, describing the delamination of thin films under cooling. We characterize the global minimizers, which correspond to films of three possible types : non delaminated, partially delaminated (called blisters), or fully delaminated. Two parameters play an important role : the length of the film and the cooling parameter. In the phase plane of those two parameters, we classify all the minimizers. As a consequence of our analysis, we identify explicitly the smallest possible blisters for this model. In the second part, we answer a long standing open question about the existence of new contractions for porous medium type equations. For m>0, we consider nonnegative solutions U(t,x) of the following equationU_t=Delta U^m.For 0<m<2, we present a new family of contractions for this equation in any dimension, which extends the L^1 contraction properties. Our contraction can be seen as the fourth known contraction for this equation. Even for the case m=1, our approach leads to new results for the standard heat equation. A second work focuses on the same problem but using a differential approach based on geodesic distances. This original and general method is used to produce families of contractions for nonlinear partial differential equations, of evolution or stationary type. We present in this part various applications of this original method. In particular, we are concerned with the porous medium and the doubly nonlinear equations

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The aim of the thesis is to propose the innovation of thermomould machine so that the complicated substitution of the distribution plate is eliminated. The diploma thesis documents the application of automatization in a small food processing company and contains a description of problems connected to the use of automatization in small and middle enterprises (SME). The thesis describes the solution of the universality of the distribution plate and its control by means of an operating systém that is implemented with a single-purpose board that is equipped with microelectronic components. The thesis ends with an economic analysis of the suggested solution.

Nobel Biocare är världsledande inom tillverkning av tandimplantat. Implantaten tillverkas av titan och måste efter tillverkning sterilförpackas för att skyddas från oönskade partiklar. Förpackningen som används är en blisterförpackning som limmas ihop i en blistermaskin. För att kontrollera att förpackningen uppfyller de krav som ställs på medicinsk tillverkning kontrolleras tätheten med hjälp av tre olika kvalitetskontroller. Dessa kontroller är tidskrävande och innebär onödig kassation då de blisterark som kontrolleras måste kasseras.  Syftet med detta arbete var att undersöka möjligheten att automatisera de manuella kvalitetskontrollerna. Automation skulle innebära besparingar i både tid och material. Det skulle också innebära att en relativt stor golvyta i förpackningsrummet skulle kunna frigöras, ytan rymmer i dagsläget två bord med diverse hjälpmedel som behövs för att utföra de manuella kvalitetskontrollerna. I samråd med företaget riktades arbetet in på att undersöka om automatiseringen skulle kunna göras med hjälp av visionsystem.  Eftersom blisterförpackningarna till större delen består av plast ansågs belysningen för visionsystemet vara den största utmaningen. Tester genomfördes på företaget Prevas i Karlstad där olika typer av ljussättning provades tillsammans med en visionkamera. Testerna visar att limmet på blisterförpackningarna är fluorescerande och blev tydligt i UV-ljus. Detta innebär att UV-ljus skulle kunna användas vid en automatisering med visionsystem.   Slutligen kontaktades olika företag, bland annat Karlskoga Automation och Neurolearn. Företagskontakt var en viktig del i arbetet då samtliga företag som kontaktades arbetar med automationslösningar. De företag som projektet presenterades för ansåg att det är möjligt att ersätta de manuella kvalitetskontrollerna med ett visionsystem och de hade möjlighet att leverera en sådan lösning till Nobel Biocare. / Nobel Biocare is a world leading company in the manufacture of dental implants. The implants are made of titanium and must be packed sterile to protect the implants from unwanted particles. The package used is a blister pack that is glued together in a blister machine. Three different quality controls are done manually to ensure that the packaging meets the requirements for medical manufacture. The quality controls are time-consuming and involve unnecessary disposal.  The purpose of this thesis was to investigate the possibility of this process being automated. Automation would mean that savings can be made for time and materials. It would also mean that a relatively large floorspace could be freed up in the packing room. The surface currently holds two tables that contains various equipment used to perform the manual quality controls. In consultation with the company the investigation was focused on using a vision system for automation. Since the blister packs mostly consists of plastic the lighting for the vision system was considered to be the biggest challenge. Lighting tests were performed at Prevas in Karlstad where a vision camera and different types of lights were used. The result shows that the blister packs contain fluorescent glue that became visible in UV light. This means that UV light can be used to automate the process with a vision system.  Finally, various companies were contacted, including Karlskoga Automation and Neurolearn. All companies that were contacted work with creating automation solutions and that made the contact important for this thesis. The companies to which the project was presented, they all considered it to be achievable. They also could deliver such a solution for Nobel Biocare.

Aromatic polyimides have found widespread applicability which can be partially attributed to their thermal stability, chemical resistance, and high glass transition temperature. However, deficiencies in their processability, solubility, transparency, and relatively high dielectric constants do not always provide the optimum properties for many specialty microelectronics applications. The incorporation of aliphatic segments to form partially aliphatic polyimides, has been used to counteract these shortcomings. Many of the potential uses of partially aliphatic polyimides require them to adhere to ceramic substrates, a main topic of this research. Polyimides and copolyimides that varied in chemical composition by their aliphatic content were characterized by their molecular weight, glass transition temperature, thermal stability, coefficient of thermal expansion, refractive index, dielectric behavior, and mechanical properties. Structure-property relationships were established. The gamma and beta sub-Tg viscoelastic relaxations were investigated to understand their molecular origins. The adhesion performance of a selected series of partially aliphatic polyimides to SiO2/Si was examined using a shaft loaded blister test, which was designed and instrumented for use in a dynamic mechanical analysis instrument. The adhesion was studied at high and low percent relative humidities and for several temperatures to examine if adhesion strength is influenced by polymer chemical composition. The adhesion energy could not be quantified for the entire series of polyimides. It was possible to interpret the quantitative adhesive fracture energies along with the qualitative adhesion strength behaviors, the failure surface analyses, and to offer an understanding of the adhesive chemical structure-physical property relationships. These understandings provide a conclusion that the incorporation of aliphatic segments into the polyimide chemical structure improves the durability of the adhesive bond to SiO2/Si under high percent relative humidities. / Ph. D.

Mechanical fatigue testing has shown that MEAs (membrane electrode assemblies) fail at lower stresses than PEMs (proton exchange membranes) at comparable times under load. The failure of MEAs at lower stresses is influenced by the presence of mud cracks in the catalyst layers acting as stress concentrators. Fatigue testing of MEAs has shown that smaller-scale cracking occurs in the membrane within these mud cracks, leading to leaking during mechanical fatigue testing and the failure of the membrane. In addition, this testing of MEAs has further established that the cyclic pressurization pattern, which affects the viscoelastic behavior of the membranes, has a significant effect on the relative lifetime of the MEA. To investigate this behavior, pressure-loaded blister tests were performed at 90 °C to determine the biaxial fatigue strength of Gore-Primea® Series 57 MEAs. In these volume-controlled tests, the leak rate was measured as a function of fatigue cycles. Failure was defined as occurring when the leak rate exceeded a specified threshold. Post-mortem characterization FESEM (field emission scanning electron microscopy) was conducted to provide visual documentation of leaking failure sites. To elucidate the viscoelastic behavior of the MEA based on these results, testing was conducted using a DMA to determine the stress relaxation behavior of the membrane. This data was then used in a FEA program (ABAQUS) to determine its effect on the mechanical behavior of the MEAs. A linear damage accumulation model used the ABAQUS results to predict lifetimes of the membrane in the MEAs. The models showed that under volume-controlled loading, the stress decays with time and the stress dropped towards the edges of the blisters. The lifetimes of the MEAs varied depending on the cycling pattern applied. This is important for understanding failure mechanisms of MEAs under fatigue loading, and will help the fuel cell industry in designing membranes that better withstand imposed hygrothermal stresses experienced during typical operating conditions. / Master of Science

This study analyzes the structure and biophysical correlates of density of two whitebark pine (Pinus albicaulis) populations in the northern Rocky Mountains. Whitebark pine is a keystone species and an important component of treeline ecosystem dynamics; however, subalpine populations have declined nearly rangewide in recent decades. Though declines in subalpine forests have been well documented in the literature, few studies have assessed population structure and habitat requirements at treeline. Various disturbances have combined to impact whitebark pine populations across its range, but the primary threat at treeline sites in the northern Rocky Mountains is white pine blister rust, caused by the exotic fungal pathogen Cronartium ribicola. In this study, I aim to: 1) assess population structure and regeneration within two geographically different treelines experiencing contrasting levels of infection, and 2) examine associations among several biophysical variables and whitebark pine density to better understand treeline habitat variability and regeneration patterns. I used density-diameter curves and non-parametric Kruskal-Wallis tests to compare population structure between sites, and developed generalized linear mixed models to assess correlations between whitebark pine density and biophysical site variables. The results demonstrate that despite very different ecosystems and blister rust infection rates, our two study sites have similar population structure. Our model results highlight marked differences between populations in terms of biophysical correlates of density. While correlations are similar within site, seedlings and saplings have stronger correlations with biophysical variables than established trees. / Master of Science

Whitebark pine (Pinus albicaulis) is a foundation and keystone species at alpine treelines of the northern Rocky Mountains and is threatened by the fungus white pine blister rust (Cronartium ribicola). This disease affects all five-needled white pines, but has caused particularly widespread mortality in whitebark pine. Objectives of this research were: 1) to characterize the landscape structure of the treeline study sites at Divide Mountain in Glacier National Park and at Wyoming Creek in the Beartooth Mountains of Montana using landscape metrics and fieldwork; 2) to determine the frequency of blister rust infection of whitebark pine trees and determine if landscape pattern is correlated with higher infection rates; and 3) to characterize the climate at alpine treeline. I used both field surveys and subsequent statistical analysis to meet these objectives. Field data collection included detailed surveys of blister rust infection of treeline whitebark pine and characterization of landscape cover type in a combined total of 60 quadrats, positioned at the study sites using a random sampling scheme stratified by aspect. Landscape analysis of metrics such as patch area, proximity and contagion were generated in FRAGSTATS software and ArcGIS. Spearman's rank correlation analysis found significant correlations between tree island patch size, patch perimeter, and percent of landscape and blister rust infection intensity at both study sites. These findings support previous research involving the relationship between patch area and blister rust infection rates and contribute to the field of landscape ecology by understanding what other landscape metrics are significant in invasive disease infection patterns. / Master of Science

Environmental fluctuations in operating fuel cells impose significant biaxial stresses in the constrained proton exchange membranes (PEM). The PEM's ability to withstand cyclic environment-induced stresses plays an important role in membrane integrity and consequently, fuel cell durability. In this thesis, pressure loaded blister tests are used to study the mechanical durability of Gore-Select® series 57 over a range of times, temperatures, and loading histories. Ramped pressure tests are used with a linear viscoelastic analog to Hencky's classical solution for a pressurized circular membrane to estimate biaxial burst strength values. Biaxial strength master curves are constructed using traditional time-temperature superposition principle techniques and the associated temperature shift factors show good agreement when compared with shifts obtained from other modes of testing on the material. Investigating a more rigorous blister stress analysis becomes nontrivial due to the substantial deflections and thinning of the membrane. To further improve the analysis, the digital image correlation (DIC) technique is used to measure full-field displacements under ramped and constant pressure loading. The measured displacements are then used to validate the constitutive model and methods of the finite element analysis (FEA). With confidence in the FEA, stress histories of constant pressure tests are used to develop linear damage accumulation and residual strength based lifetime prediction models. Robust models, validated by successfully predicting fatigue failures, suggest the ability to predict failures under any given stress history whether mechanically or environmentally induced - a critical step in the effort to predict fuel cell failures caused by membrane mechanical failure. / Master of Science

Three epoxy-coated reinforcing steel (ECR) types removed from job sites, one shipped directly from the coater's plant, three commercial corrosion inhibitors, and one ECR plus a corrosion inhibitor were evaluated as reinforcing steel corrosion protection systems against chloride induced corrosion. The three corrosion inhibitors were calcium nitrite, an aqueous mixture of esters and amines, and a mixture of alcohol and amine. The ECR was tested in two groups, 0% and 1% coating damage. Corrosion protection performance was evaluated by the amount of visually observed blister surface area, for the ECR, and corroded surface area, for the tested corrosion inhibitors. Results of the ECR testing demonstrated that coating debondment and corrosion of ECR is directly related to the amount of damage present in the coating, as well as coating thickness. For the bare steel tested with and without corrosion inhibitors, the results showed that corrosion increases with increasing chloride concentrations. Corrosion inhibition characteristics were demonstrated only by the calcium nitrite corrosion inhibitor. A corrosion protection evaluation test was developed for concrete corrosion inhibitor admixtures. The test solution is a simulated concrete pore water. Corrosion is accelerated by evaluating the temperature to field conditions of 40 C. The test consists of a 7 day pretreatment period followed by a 90 day test period. The corrosive sodium chloride is added to the solution containing the bare or epoxy-coated reinforcing steel specimens after the 7 day pretreatment period. In addition, the solution is periodically saturated with oxygen. / Master of Science