Les agro-composites font l'objet de nombreuses études et applications industrielles en raison des multiples propriétés mécaniques qu'ils présentent. Ces propriétés présentent de grandes perspectives comparées à celles des composites traditionnels. Cependant les connaissances sur le comportement mécanique de l'interface fibre/matrice restent limitées. De plus, la différence de propriété entre la fibre hydrophile et la matrice hydrophobe peut causer des défauts au niveau de l’interface. Il est donc important de caractériser finement la décohésion à l'interface au cours d'une sollicitation. Plusieurs méthodes ont été proposées dans la littérature, elles sont généralement très complexes à mettre en œuvre et sont coûteuses. Dans cette étude, nous avons développé une méthode de caractérisation en se basant sur l'essai de « pull-out ». La géométrie de la fibre a été prise en compte dans le calcul des propriétés mécaniques de l'interface par la mise à profit d'une approche inspirée de la tomographie. L'influence de la température d'élaboration sur les propriétés mécaniques de l'interface a été étudiée de manière à définir la température optimale. L'évolution des propriétés interfaciales a été suivie au cours d'un vieillissement en humidité relative. Après quatre semaines, la résistance au cisaillement et la rigidité au cisaillement de l'interface sont diminuées fortement alors que la déformation à la rupture est augmentée / Agro-composites are increasingly studied and applied to various industries over recent years due to good mechanical properties compared to conventional composites especially in terms of specific values. However, since low adhesion between the hydrophilic fiber and hydrophobic matrix, which occurs one of the main breaks modes in this kind of material, the characterization of the interface becomes a key problem. For investigation of this issue, existing methods show limitation for reasons of complexity (in preparation, in principle) and of cost. In this study, we developed a « pull-out ». In particular, the real fiber geometry of the plant fiber was taken into the calculation of mechanical properties of interface using a tomography inspired method. By checking the effective temperature of the molding then varying it, we studied the effect of this processing parameter to mechanical properties of fibre/matrix interface and determined the optimal conditions. The developed experimental protocol is applied to aged interfaces in order to clarifying the evolution of interfacial properties during the aging time to relative humidity. After four weeks, the interfacial shear strength and the shear modulus of the interface were greatly reduced while the shear deformation at the rupture was greatly increased

Cette thèse explore l’utilisation des réseaux Bayésiens (RB) afin de répondre à des problématiques de dégradation en grandes dimensions concernant des infrastructures du génie civil. Alors que les approches traditionnelles basées l’évolution physique déterministe de détérioration sont déficientes pour des problèmes à grande échelle, les gestionnaires d’ouvrages ont développé une connaissance de modèles nécessitant la gestion de l’incertain. L’utilisation de la dépendance probabiliste se révèle être une approche adéquate dans ce contexte tandis que la possibilité de modéliser l’incertain est une composante attrayante. Le concept de dépendance au sein des RB s’exprime principalement de deux façons. D’une part, les probabilités conditionnelles classiques s’appuyant le théorème de Bayes et d’autre part, une classe de RB faisant l’usage de copules et corrélation de rang comme mesures de dépendance. Nous présentons à la fois des contributions théoriques et pratiques dans le cadre de ces deux classes de RB ; les RB dynamiques discrets et les RB non paramétriques, respectivement. Des problématiques concernant la paramétrisation de chacune des classes sont également abordées. Dans un contexte théorique, nous montrons que les RBNP permet de caractériser n’importe quel processus de Markov. / This thesis explores high-dimensional deterioration-related problems using Bayesian networks (BN). Asset managers become more and more familiar on how to reason with uncertainty as traditional physics-based models fail to fully encompass the dynamics of large-scale degradation issues. Probabilistic dependence is able to achieve this while the ability to incorporate randomness is enticing.In fact, dependence in BN is mainly expressed in two ways. On the one hand, classic conditional probabilities that lean on thewell-known Bayes rule and, on the other hand, a more recent classof BN featuring copulae and rank correlation as dependence metrics. Both theoretical and practical contributions are presented for the two classes of BN referred to as discrete dynamic andnon-parametric BN, respectively. Issues related to the parametrization for each class of BN are addressed. For the discrete dynamic class, we extend the current framework by incorporating an additional dimension. We observed that this dimension allows to have more control on the deterioration mechanism through the main endogenous governing variables impacting it. For the non-parametric class, we demonstrate its remarkable capacity to handle a high-dimension crack growth issue for a steel bridge. We further show that this type of BN can characterize any Markov process.

The process and outcome of psychoanalytic psychotherapy have been studied for a long time. However, the experiences of patients, particularly in therapies where goals were not met, have not yet been the target of extensive research. Psychoanalytic psychotherapy with young adults might face particular challenges. The overall aim of this thesis was to explore the experiences of young adults in psychoanalytic psychotherapy, with a particular focus on differences between suboptimal therapies and therapies with generally good outcome. The setting was naturalistic, and perspectives of the patient, therapist and observer were combined. Qualitative and quantitative methods were used. Study I explored experiences of psychotherapy process and outcome among seven patients in psychoanalytic psychotherapy, who expressed dissatisfaction. Interviews at termination and 18 months later were analysed using grounded theory and compared to therapist experiences. Patients experienced abandonment with their problems in and after therapy, since therapy according to the patients lacked connections to daily life, as well as flexibility, activity and understanding from the therapist. Therapists presented a different picture of the same therapies, mainly focused on the difficulties of the patients. Study II analysed the experiences of 20 non-improved or deteriorated young adult psychotherapy patients at termination of therapy and 36 months later. Non-improvement and deterioration were calculated based on the reliable change index on self-rating scores. The grounded theory analysis of interviews established spinning one’s wheels as a core category. The relationship to the therapist was described as artificial, although at times helpful. Participants experienced their own activity in life and active components of therapy as helpful, but thought focus in therapy was too much on past experiences. Study III explored the experiences of 17 young adult patients, in psychoanalytic individual or group therapy, overcoming depression. The analysis of interviews from therapy termination and 18 months later indicated that finding an identity and a place in life were perceived as intertwined with symptom relief. Negative experiences included difficulties to change oneself, fear of change, and problems in therapy, such as too little activity on the therapist’s part. The results were discussed in relation to young adulthood, therapeutic alliance, mentalization, and attachment. The conclusion was expressed in a comprehensive process model of suboptimal therapy with young adults, with suggested ways to prevent such a development. The therapist’s meta-communication and correct assessment of the patient’s mentalization capacity from moment to moment are proposed as crucial. Regarding clinical implications, therapists of young adult patients need to establish meta-communication on therapy progress, as even experienced therapists might be unaware of dissatisfaction or deterioration. Meta-communication could be considered part of the treatment itself, as it may foster mentalization and good outcome. Further, the period of young adulthood entails decisions and developing an adult life, and therapists need to make room for this by active interventions.

This research aims to assess the causes of inefficient and unstable operation of centrifugal compressors and turboexpanders in process gas applications in order to provide a solution for performance restoration and enhancement. It encompasses thermodynamic and flow evaluations to examine the efficiency and operating range improvement options of new units. Besides, this work is complemented by a technoeconomic analysis to provide a rounded outcome from these studies. In order to achieve the desired objectives, a novel integrated approach has been developed to assess the design and performance of multi-stage centrifugal compressors. The proposed systematic methodology involves five basic elements including evaluation of compressor selection, compressor sizing and casing structure, performance prediction at the design and off-design conditions, modelling of efficiency and head deterioration causes; and stage design evaluation. This will contribute towards evaluating the geometrical parameters of the new units’ designs at the early preliminary design phase, and thus, will be useful to identify the options for efficiency and operating range enhancements. For installed units, this approach can be implemented to assess the cause of inefficient and unstable operation by assessing the available operation data. A method was developed to predict the performance curve of multi-stage centrifugal compressor based on a stage stacking technique. This approach considers the advantages of Lüdtke and Casey-Robinson methods with an incorporation of a methodology for compressor selection and sizing to generate more accurate results. To emphasize the validity of the developed model, it has been evaluated for both low and high flow coefficient applications. The obtained results show a significant improvement in the estimated efficiency, pressure ratio, shaft power and operating range as compared with the existing methods. The centrifugal compressor is designed to run under various operating conditions and different gas compositions with the primary objective of high efficiency and reliability. Therefore, a new iterative method has been developed to predict the equivalent compressor performance at off-design conditions. This technique uses the performance parameters at design conditions as a reference point to derive the corresponding performance characteristics at numerous suction conditions with less dependency on the geometrical features. Through a case study on a gas transport centrifugal compressor, it was found that the developed approach can be applied for design evaluation on the expected variation of working conditions, and for the operation diagnosis of installed units as well. Furthermore, a parametric study has been conducted to investigate the effect of gas properties on the stage efficiency, surge margin, and compressor structure. The obtained results support the need for considering the gas properties variation when the off-design performance is derived. To evaluate the impact of internal blockage on the performance parameters, this study proposed an approach to model the effect of non-reactive deposits, which has been qualified using four operation cases and the obtained results are compared with the internal inspection findings from the stage overhauling process. This also covers the influential aspects of flow blockage on the technical and economic values. Since the main challenge here is to analyze the process gas composition in real time, the influences of the non-reactive deposits have been compared with the effect of the unanticipated gas composition change. Subsequently, it has turned out that the pressureratio parameter is not enough to assess the possibility of flow blockage and unexpected gas properties change. Moreover, it was observed that the stage discharge pressure was more sensitive to the fouled aftercooler comparing with suction and internal blockage. However, the effect of contaminated aftercooler on the surge point and discharge pressure and temperature of the upstream stage was found greater than its impact on the shaft power. Thus, a substantial surge margin reduction was detected when the first stage was operating with a fouled aftercooler comparing with the measured reduction as a result of unanticipated gas properties change. Furthermore, a larger pressure ratio drop was measured in the case of liquid carryover which revealed a more significant impact of the two phases densities difference comparing with the gas volume fraction (GVF) effect. The possibility of hydrate formation has been assessed using hydrate formation temperature (HFT) criteria. Additionally, this research highlights a number of challenges facing the selection of typical centrifugal stage design by assessing the contribution of design characteristics on the operating efficiency and stable flow range. Besides, an empirical-based-model was established to select the optimum impeller and diffuser configurations in order to make a compromise decision based on technical and economic perspective. It was concluded that there is no absolute answer to the question of optimum rotor and stator configuration. The preliminary aerothermodynamic evaluation exposed that the selection of the optimum impeller structure is governed by several variables: stage efficiency, pressure loss coefficient, manufacturing cost, required power cost, resonance frequency and stable operating range. Hence, an evaluation is required to compromise between these parameters to ensure better performance. Furthermore, it was argued throughout this study that the decision-making process of the typical stage geometrical features has to be based upon the long-term economic performance optimization. Thus, for higher long-term economic performance, it is not sufficient to select the characteristics of the impeller and diffuser geometry based on the low manufacturing cost or efficiency improvement criterion only. For turboexpanders, a simple and low cost tool has been developed to determine the optimum turboexpander characteristics by analysing the generated design alternatives. This approach was used in designing a turboexpander for hydrocarbon liquefaction process. Moreover, since the turboexpanders are expected to run continuously at severe gas conditions, the performance of the selected turboexpander was evaluated at different inlet flow rates and gas temperatures. It has turned out that designing a turboexpander with the maximum isentropic efficiency is not always possible due to the limitations of the aerodynamic parameters for each component. Therefore, it is necessary to assess the stage geometrical features prior the construction process to compromise between the high capital cost and the high energetic efficiency.

This research study explored the effects of a public servants‟ strike on psychiatric patients. This is achieved through investigating the subjective lived experiences of events prior to, during and ensuing a public servants' strike. In addition, strike action within the health care sector as a worldwide phenomenon is discussed. This provides a conceptual understanding of strike action within the health care sector, as well as critical issues raised around the use of strikes as a medium of communication. During the public servants' strike of August 2010, 446 patients were discharged from a specialized psychiatric facility in the greater Gauteng region. The sample for this research was taken from this population and comprises of three (n=3) psychiatric patients, two Afrikaans speaking males and one Sotho speaking male. At the time of the interview, all three participants had been hospitalized and received further psychiatric treatment. The researcher made use of Interpretive Phenomenological Analysis (IPA) as the method to gather and interpret the raw data. The data is discussed within three subordinate themes, namely the subjective experiences prior to, during and ensuing the strike. In addition global themes throughout the patient‟s subjective lived experiences are discussed without sequential significance. The results from this study support current literature that strikes have a direct impact on the treatment of psychiatric patients. In addition the subjective accounts of the patients did not indicate any significant deterioration in functioning during the strike. However in subsequent months following their discharge, all of the participants experienced some form of conflict which contributed to their rehospitalisation. Copyright / Dissertation (MA)--University of Pretoria, 2013. / Psychology / unrestricted

Submitted by biblioteca unifenas (biblioteca@unifenas.br) on 2016-05-06T13:19:09Z No. of bitstreams: 1 Gilmara da Silva Melo Dissertacao.pdf: 988532 bytes, checksum: d457e85e340065bc994acfb16c3eb9cb (MD5) / Made available in DSpace on 2016-05-06T13:19:10Z (GMT). No. of bitstreams: 1 Gilmara da Silva Melo Dissertacao.pdf: 988532 bytes, checksum: d457e85e340065bc994acfb16c3eb9cb (MD5) Previous issue date: 2015-12-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The sheep industry in Brazil is presented as a promising activity, not only for increased consumption of meat of this species, but also the future possibility that sees both the national and international market. Among many factors that can contribute to the consolidation of this activity, the quality of meat is the main factor. Although the demand for lamb is high, supply is low and unstable, being a limiting factor in the marketing of this product in addition to the lack of concise information of the quality characteristics and physical-chemical profile. Based on the above, the aim of this research was to determine the pH, color, tenderness, weight loss by cooking, water holding capacity and profile of fatty acids from lamb supplemented with vitamin E. The experiment was conducted in partnership with the Animal Science Department of Universidade Federal de São João del Rei (UFSJ) and analyzes were sent for analysis to the Department of Food science at the Universidade Federal def Lavras and Meat Technology Laboratory of the Universidade Estadual Paulista, campus Jaboticaba. Twelve Texel lambs were used with initial average weight of 25 kg and 42 kg final. And the diet consisted of hay Tifiton 85, ground corn, soybean meal and commercial mineral supplement formulated according to recommendations of NRC (2007), with or not vitamin E. The experimental design was completely randomized with two treatments and six replications. Data were analyzed by the GLM procedure of the SAS (2001) and the averages compared by test T at 5% probability. In this study, the use of vitamin E depreciated the quality of sheep meat. / A ovinocultura de corte no Brasil apresenta-se, como uma atividade promissora, não somente pelo aumento no consumo da carne desta espécie, mas também pela possibilidade futura de uma carne de qualidade, que se vislumbra tanto para o mercado nacional como internacional. Entre os vários fatores que podem contribuir para a consolidação desta atividade, a qualidade da carne é a principal. Embora a demanda pela carne ovina seja elevada, a oferta é baixa e instável, sendo um fator limitante na comercialização deste produto, além da carência de informações sobre as características de qualidade e perfil físico-químico. Com base no exposto, objetivou-se com esta pesquisa determinar o pH, cor, maciez, perda de peso por cozimento, capacidade de retenção de água e perfil de ácidos graxos da carne de cordeiros suplementados com vitamina E. O experimento foi conduzido em parceria com o Departamento de Zootecnia da Universidade Federal de São João Del Rei (UFSJ) e as amostras foram enviadas para análise ao Departamento de Ciência dos alimentos da Universidade Federal de Lavras e ao Laboratório de Tecnologia de Carnes da Universidade Estadual Paulista, Câmpus de Jaboticabal. Foram utilizados 12 cordeiros da raça Texel com peso inicial médio de 25 Kg e final de 42 Kg. A dieta composta foi feno de Tifiton 85, milho moído, farelo de soja e suplemento mineral comercial, formulada segundo recomendações do NRC (2007), acrescida ou não de vitamina E. O delineamento experimental utilizado foi o inteiramente casualizado com dois tratamentos e seis repetições. Os dados foram analisados pelo procedimento GLM do SAS (2001) e as médias comparadas pelo teste t, a 5% de probabilidade. Neste estudo, a utilização da vitamina E depreciou a qualidade da carne ovina.

Essay is devoted to assessment of the existing structure. Primarily is focused on the buildings history, performed structures upgrades, design of structural plans and design process to improve remaining working life of the building.

This research aimed to determine whether wood microsites ("nurse logs"), which are regeneration sites in Pacific Northwest (PNW) subalpine forests, supported regeneration at timberline-alpine meadow borders. Upward advance of forests and conifer invasion into alpine meadows, which may be occurring in conjunction with climate warming, have gained worldwide attention. Successful alpine meadow seedling regeneration depends on suitable substrate availability, or microsites, for seedling establishment. To better understand factors associated with wood microsite occurrence, mechanisms of wood input were determined and four specific hypotheses were posed to assess: (1) seedling density and seedling survival; (2) growing season length, summer mean growing temperature, and growing degree hours (GDH); (3) active measures of seedling growth; and (4) global wood microsite climate associations. Of four studies, three were conducted in the Cascade Mountains of Washington state along a west - east precipitation gradient and one study, assessed various microsites globally. For Cascades-related research, wood and adjacent soil substrate temperature, moisture, and associated seedling density, survival, stomatal conductance, water potential, and leaf nitrogen were compared by percent transmitted radiation at 4 to 14 study sites. Analysis of variance (ANOVA), t-tests, regressions, and classification and regression trees (CARTs) were used to assess significance of comparisons. Wood microsites, common at 13 of 14 random Cascade sites, had greater seedling densities, greater seedling survival, greater volumetric moisture content (VWC), greater temperature, and greater number of GDH, as compared to adjacent soils. Greater seedling densities were positively associated with VWC (> 12%), conditions most commonly associated with wood substrate presence. For sites having > 25% percent transmitted radiation, positive relationships existed between stomatal conductance and VWC. Globally, high-elevation forests with wood microsites had mean annual precipitation from 86 cm to 320 cm and mean annual temperatures from 1.5°C to 4.7°C. In general, wood microsites facilitated alpine meadow regeneration better than adjacent soils. Management implications included enhanced understanding of factors associated with upward forest advance and wood use for restoration. Globally, wood microsites importance is likely underrepresented. Wood microsites role with warming climate will depend on precipitation pattern, timing, magnitude, and frequency.

No description available.

The durability of concrete is of major concern in all types of concrete structures where the combined effect of exposure conditions and the type and quality of the concrete material usually determines the rate of degradation. Furthermore, there are synergy effects between different deterioration mechanisms, which means that the combined rate of degradation is higher than the sum of the individual rates of each mechanism. Therefore, to accurately predict the residual service life of existing structures or when designing new structures, it is essential to consider all these aspects. This means that various chemical and physical processes, as well as how these interact, must be taken into account in models aiming to be used for service life predictions. This thesis presents the first part of a research project with the aim to investigate common deterioration mechanisms of concrete in hydraulic structures, and to improve the knowledge how these and other related phenomena can be described using mathematical models. The objective is also to study how different mechanisms interact and to find suitable approaches to account for these interactions in the models. To this end, a literature survey on commonly detected damage in hydraulic structures is presented. In addition, it also addresses in what types of and where in hydraulic structures the various damage types are usually observed. The mathematical models presented in this part of the project are focused on long-term water absorption in air-entrained concrete as well as on freezing of partially saturated air-entrained concrete. Both models are based on a multiphase description of concrete and poromechanics to describe the coupled hygro-thermo-mechanical behaviour. The thesis also presents some of the basic concepts of multiphase modelling of porous media, including discretization of the models using the finite element method (FEM). Furthermore, it covers the simplifications that are usually introduced in the general macroscopic balance equations for mass, energy and linear momentum when modelling cement-based materials. To verify the developed models and to show their capabilities, simulation results are compared with experimental data, in situ measurements and other simulations from the literature. The results indicate that both models perform well and can be used to predict long-term moisture conditions in hydraulic structures as well as freezing-induced strains in partially saturated air-entrained concrete, respectively. Even though no interactions with other deterioration mechanisms are included in the models, the development and use of these have given insights to which parameters that are important to consider in such extensions. Furthermore, based on the insights gained, the complexity of describing the full interactions between several mechanisms in mathematical models is also discussed. It is concluded that models aiming to be used for service life predictions of hydraulic structures in day-to-day engineering work need to be simplified. However, the type of advanced models presented in this thesis can serve as a basis to study which aspects and parameters that are essential to consider in simplified prediction models. / Beständigheten hos betong är av avgörande betydelse i alla typer av betongkonstruktioner där den kombinerade effekten av exponeringsförhållanden samt typ och kvalitet på betongmaterialet vanligtvis avgör nedbrytningshastigheten. Dessutom finns synergieffekter mellan olika nedbrytningsmekanismer som innebär att den kombinerade nedbrytningshastigheten är större än summan av de enskilda nedbrytningshastigheterna. För att noggrant kunna prediktera den återstående livislängden hos befintliga konstruktioner eller vid design av nya konstruktioner är det därför viktigt att ta hänsyn till samtliga av dessa aspekter. Detta innebär att olika kemiska och fysikaliska processer, samt hur dessa interagerar med varandra, måste tas i beaktande i modeller som avses användas för livslängdsbedömningar. Den här licentiatuppsatsen presenterar den första delen av ett forskningsprojekt där målet är att studera vanligt förekommande nedbrytningsmekanismer i vattenbyggnadskonstruktioner och att öka kunskapen om hur dessa och andra relaterade fenomen kan beskrivas med matematiska modeller. Målet är också att studera hur olika nedbrytningsmekanismer samverkar och att hitta lämpliga tillvägagångssätt att ta hänsyn till dessa interaktioner i modellerna. För detta ändamål presenteras en litteraturstudie avseende vanligt förekommande skador i vattenbyggnadskonstruktioner. Dessutom behandlar denna i vilka typer av vattenbyggnadskonstruktioner och var i dessa som de olika typerna av skador vanligtvis observeras. De matematiska modeller som presenteras i denna del av projektet är inriktade på långtidsabsorption av vatten i lufttillsatt betong samt på frysning i delvis vattenmättad lufttillsatt betong. Båda modellerna är baserade på en multifasbeskrivning av betong samt poromekanik för att beskriva det kopplade hydro-termo-mekaniska beteendet. Uppsatsen presenterar också några av de grundläggande koncepten gällande multifasmodellering av porösa material, inklusive diskretisering av modellerna genom användning av finita elementmetoden (FEM). Dessutom beskrivs de förenklingar som vanligtvis införs i de generella makroskopiska balansekvationerna för massa, energi och rörelsemängd då cementbaserade material modelleras. Simuleringsresultat från de utvecklade modellerna jämförs med försöksdata, fältmätningar samt andra simuleringsresultat från litteraturen för att verifiera modellerna samt visa hur de beter sig. Resultaten visar att båda modellerna ger tillfredställande resultat och kan användas för att uppskatta de långsiktiga fuktförhållandena i vattenbyggnadskonstruktioner samt frysinducerade töjningar i delvis vattenmättad lufttillsatt betong. Även om inga interaktioner mellan andra nedbrytningsmekanismer inkluderades i modellerna, så har utvecklingen samt användandet av dessa gett insikter gällande vilka parametrar som är viktiga att beakta i sådana vidareutvecklingar. Baserat på dessa insikter diskuteras också komplexiteten i att beskriva interaktionen mellan flertalet mekanismer i matematiska modeller. Det konstateras också att modeller som avses användas i dagligt ingenjörsarbete för livstidsbedömningar av vattenbyggnadskonstruktioner behöver förenklas. Däremot kan den typ av avancerade modeller som presenteras i denna uppsats användas som en grund för att studera vilka aspekter och parametrar som är viktiga att beakta i förenklade modeller. / <p>QC 20180403</p>