A whole genome scan was conducted to identify and fine map QTL regions for ultrasound and carcass merit traits in beef cattle. A total of 465 steers and bulls, genotyped for 4592 SNPs, were analysed for 16 ultrasound and carcass merit traits using interval mapping, single marker regression and Bayesian shrinkage approaches. Thirty QTL and 22 SNPs associated with traits were identified by interval mapping and single marker regression respectively. In Bayesian shrinkage estimation, 218 QTL were identified, wherein 11 of the 30 QTL identified by interval mapping were confirmed. The proportions of QTL variance on the trait variations estimated by Bayesian shrinkage analysis were relatively small. They ranged from 0.1 to 4.8% compared to 6.1 to 11.7% in interval mapping because the QTL in Bayesian approach were adjusted to remove effects of other QTL in the genome. These results are useful for detection of underlying causative QTN variants. / Animal Science

Global concern about the environmental impacts of waste disposal and stringent implementation of environmental laws lead to numerous research on recycled materials. Increased awareness about the inherent engineering values of waste materials, lack of landfill sites and strong demand for construction materials have encouraged research on composite materials, which are either fully or partly made of recycled materials. This trend is particularly strong in transportation and geotechnical projects, where huge quantities of raw materials are normally consumed. Owing to the low mass-to-volume ratio, disposal of Expanded Polystyrene (EPS) is a major problem. In addition, EPS recycling methods are expensive, labour intensive and energy demanding. Hence, this thesis is focused on the development of a new soil composite made by mixing recycled EPS with expansive clays. Given the high cost of damage to various buildings, structures and pavements caused by the unpredictable ground movements associated with expansive soils, it has been considered prudent to try and develop a new method of soil modification using recycled EPS beads as a swell-shrink modifier and desiccation crack controller. The innovative application of recycled EPS as a soil modifier will minimise the quantity of waste EPS destined to the landfill considerably. An extensive experimental investigation has been carried out using laboratory reconstituted expansive soils - to represent varied plasticity indices - consisting of fine sand and sodium bentonite. Three soils notated as SB16, SB24 and SB32 representing 16%, 24% and 32% of bentonite contents respectively were tested with four EPS contents of 0.0%, 0.3%, 0.6% and 0.9%. The tests performed include compaction, free swell, swell pressure, shrinkage, desiccation, shear strength and hydraulic conductivity. All the tests have been performed at the respective maximum dry unit weight and optimum moisture content of the mixes. It has been observed that by mixing of recycled EPS beads with the reconstituted soil, a lightweight geomaterial is produced with improved engineering properties in terms of dry unit weight, swelling, shrinkage and desiccation. The EPS addition depends on the moulding moisture content of the soil. With increasing moisture content, additional EPS can be added. Also, there is a reduction in dry unit weight with the addition of EPS. Furthermore, the reduction of swell-shrink potential and desiccation cracking in soils, for example, is related to the partial replacement of soil particles as well as the elasticity of the EPS beads. There is a reduction in shear strength with the addition of EPS to soils. However, mixing of chemical stabilisers along with EPS can enhance the strength in addition to improved overall properties.

Low Pressure Die Casting (LPDC) process is one the most common casting process to produce structural automotive components, such as alloy wheels and suspension components. It has been identified that cavity filling and solidification process are two most critical aspects to produce premium quality casting components.During the solidification process of casting alloy, it is a well known phenomenon that metal experiences volumetric shrinkage due to its density difference between liquid and solid phase. When this volumetric shrinkage is not properly compensated, then a casting defect commonly known as solidification shrinkage occurs. The solidification shrinkage has very detrimental effects on structural integrity required for premium quality casting such as aluminium alloy wheels.Literature and practical experiences of foundry men show that it is critical to achieve unidirectional solidification pattern by avoiding an isolated hot spot in order to minimise the solidification shrinkage. However, it is found that the geometry of industrial casting applications is often constrained by other design factors that would not naturally avoid these isolated hot spots. The subject of this research, aluminium alloy wheels, is not excluded from this constraint.In aluminium alloy wheels, an isolated hot spot is commonly observed in an area known as rim and spoke junction due to its geometry constraints. Consequently, the solidification shrinkage is commonly experienced, which is undesirable due to its detrimental effects for the structural integrity of alloy wheels. In order to minimise the solidification shrinkage, forced cooling method is applied to avoid an isolated hot spot. The control of this forced cooling is achieved by cooling media, flow rate of cooling media and duration cooling circuit. Foundry experiments in industrial environment were conducted producing aluminium alloy wheels using commercially treated A356 (Al-Si) alloy, where different durations of cooling circuit were used to understand the sensitivity of solidification shrinkage formation to the duration of cooling circuit. This was followed by metallurgical structure analysis and numerical modelling to suggest the sensitivity of cooling circuit duration in controlling solidification shrinkage.The major finding conclusion of this research is that control of the shrinkage formation is not very sensitive to the duration cooling circuit. It is suggested that as casting solidifies initially from the mould wall, it retracts away from the cast-mould interface due to thermal contraction. Consequently, air gap is formed between casting and mould interface, creating an effective thermal resistance layer. Thereafter, heat transfer across the cast-mould interface is not sensitive to the change in the cooling channel which is a distance to the cast-mould interface.Some limitations of numerical modelling and metallurgical analysis were also identified during this research and recommendations were made to improve the accuracy of local hot spot prediction in production of aluminium alloy wheels. More specifically, numerical modelling of the effect of grain refinement and use of non homogeneous material property (particularly fraction of solid) for rapidly chilled area. Fraction of eutectic rather than secondary dendrites arm spacing is a proper microstructure parameter that can be used to locate the hot spot.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2006. / Härtill 5 uppsatser.

Le projet français de stockage des déchets nucléaires, géré par l’Andra, nécessite la récolte de données expérimentales sur la durabilité des bétons de référence. Dans cette étude, les sollicitations prises en compte sont les processus de désaturation/resaturation, la charge thermique et l’évolution mécanique. Ainsi l’analyse porte ainsi sur le couplage thermo-hydro-mécanique des bétons de référence de l’Andra, fabriqués à base de ciment CEM I et CEM V/A. L’état de saturation en eau et les retraits des matériaux, soumis à la dessiccation ou à la resaturation, sont conditionnés par les différentes conditions thermiques et hydriques imposées, ainsi que de leurs caractéristiques microstructurales. Par ailleurs, l’étude de l’évolution mécanique est approfondie à 20°C en fonction de l’état de saturation en eau. A court terme, différents essais ponctuels mettent en évidence un endommagement hydrique qui conditionne le comportement mécanique. A long terme, l’étude du fluage sous dessiccation révèle le couplage existant entre la durabilité, l’évolution mécanique des matériaux et la dessiccation / The French project of the storage of nuclear wastes, which is managed by the Andra, needs some experimental data on the durability of the concrete. Loadings which are taken into account are the desaturation/resaturation processes, the heat load and the mechanical evolution. Hence this study focuses on the coupling thermo-hydro-mechanical on concretes of the research program of Andra, made with CEM I and CEM V/A cement type. The water saturation degree and shrinkages of materials, which are subjected to desiccation or resaturation, are dependent on the imposed thermal and hydrous conditions and on their microstructural characteristics. Moreover the study of the mechanical evolution is gone further at 20°C in function of the water saturation degree. Different short-term tests highlight a hydrous damage, which determine the mechanical behaviour. The long-term study of desiccation creep shows the coupling between the durability, the mechanical evolution and the desiccation

[pt] Mavroeidis (2005) alertou que equações de equlíbrio motivadas por modelos macroeconômicos com expectatvas racionais poderiam ser fracamente identificados devido ao uso de instrumentos fracos. Eu argumento que, embora tais preocupações sejam legítimas, elas não são empiricamente graves, contanto que instrumentos sejam devidamente selecionados. Eu utilizo um modelo DSGE estimado de média escala como laboratório para avaliar estimação uniequacional de condições de equilíbrio macroeconômicas. Apresento estimadores baseados no LASSO que selecionam instrumentos e tem boa performance em amostra finita, que argumento funcionam melhor em relações que incluem termos de expectativa, como a Curva de Phillips Novo Keynesiana. Por último, faço uma aplicação empírica para a Curva de Phillips da economia dos Estados-Unidos e as estimativas validam um componente de expectativa predominante. / [en] Mavroeidis (2005) alerted that equilibrium conditions from typical rational expectations macroeconomic models could be weakly identified due to the use of poor instruments. I argue that, although such concerns are legitimate, they are not empirically severe, provided instruments are properly selected. I use an estimated medium scale DSGE model as a laboratory to assess single-equation estimation of macroeconomic equilibrium conditions. I present LASSO-based estimators to select instruments that perform well in finite samples, which I argue have a better chance of performing for forward-looking relationships, such as the New Keynesian Phillips Curve. Finally, I provide an empirical application of the estimators for the US economy s Phillips Curve and show that it validates a dominant forward looking behavior.

Dynamic covariance estimation for multivariate time series suffers from the curse of dimensionality. This renders parsimonious estimation methods essential for conducting reliable statistical inference. In this paper, the issue is addressed by modeling the underlying co-volatility dynamics of a time series vector through a lower dimensional collection of latent time-varying stochastic factors. Furthermore, we apply a Normal-Gamma prior to the elements of the factor loadings matrix. This hierarchical shrinkage prior effectively pulls the factor loadings of unimportant factors towards zero, thereby increasing parsimony even more. We apply the model to simulated data as well as daily log-returns of 300 S&P 500 stocks and demonstrate the effectiveness of the shrinkage prior to obtain sparse loadings matrices and more precise correlation estimates. Moreover, we investigate predictive performance and discuss different choices for the number of latent factors. Additionally to being a stand-alone tool, the algorithm is designed to act as a "plug and play" extension for other MCMC samplers; it is implemented in the R package factorstochvol. (author's abstract) / Series: Research Report Series / Department of Statistics and Mathematics

abstract: Early-age cracks in fresh concrete occur mainly due to high rate of surface evaporation and restraint offered by the contracting solid phase. Available test methods that simulate severe drying conditions, however, were not originally designed to focus on evaporation and transport characteristics of the liquid-gas phases in a hydrating cementitious microstructure. Therefore, these tests lack accurate measurement of the drying rate and data interpretation based on the principles of transport properties is limited. A vacuum-based test method capable of simulating early-age cracks in 2-D cement paste is developed which continuously monitors the weight loss and changes to the surface characteristics. 2-D crack evolution is documented using time-lapse photography. Effects of sample size, w/c ratio, initial curing and fiber content are studied. In the subsequent analysis, the cement paste phase is considered as a porous medium and moisture transport is described based on surface mass transfer and internal moisture transport characteristics. Results indicate that drying occurs in two stages: constant drying rate period (stage I), followed by a falling drying rate period (stage II). Vapor diffusion in stage I and unsaturated flow within porous medium in stage II determine the overall rate of evaporation. The mass loss results are analyzed using diffusion-based models. Results show that moisture diffusivity in stage I is higher than its value in stage II by more than one order of magnitude. The drying model is used in conjunction with a shrinkage model to predict the development of capillary pressures. Similar approach is implemented in drying restrained ring specimens to predict 1-D crack width development. An analytical approach relates diffusion, shrinkage, creep, tensile and fracture properties to interpret the experimental data. Evaporation potential is introduced based on the boundary layer concept, mass transfer, and a driving force consisting of the concentration gradient. Effect of wind velocity is reflected on Reynolds number which affects the boundary layer on sample surface. This parameter along with Schmidt and Sherwood numbers are used for prediction of mass transfer coefficient. Concentration gradient is shown to be a strong function of temperature and relative humidity and used to predict the evaporation potential. Results of modeling efforts are compared with a variety of test results reported in the literature. Diffusivity data and results of 1-D and 2-D image analyses indicate significant effects of fibers on controlling early-age cracks. Presented models are capable of predicting evaporation rates and moisture flow through hydrating cement-based materials during early-age drying and shrinkage conditions. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2011

L’immobilier est un actif récalcitrant, hétérogène et illiquide, ces incertitudes constituent l`appréhension du risque en immobilier d`entreprise. Nous suggérons que le risque peut être évaluer à travers une somme de mesure de risque : en premier lieu dans une approche globale de la volatilité, ce que peut nous proposer une analyse de portefeuille, puis dans une approche plus fine, que peut nous donner la prime de risque d`un marché bureau. Notre travail doctoral se propose d’adapter les outils hérités du monde financier à l’évaluation du risque dans les principaux marchés de bureau Européen. Notre thèse sera rédigée en anglais et la question de recherche s`articulera autour de trois grands axes que nous illustrons sous forme d’articles. / The real estate asset class is tangible, heterogeneous and illiquid. It gives a specific investment universe that needs to be understood by investors, because the uncertainties created by this universe compose the risk of real estate investment. We suggest modelling risks across a sum of risk unit appraisal, on one hand, in constructing portfolio analysis, and on the other hand, through the office market risk premium modelling. Our doctoral study proposes to adapt financial theorems to risk modelling in the main European office markets. Our thesis will be written in Englishand its body will be articulated around three axes whereby those will be illustrated under the form of article.

As vigas mistas de aço e concreto têm sido muito empregadas em obras civis de pequeno e grande porte. O emprego em conjunto de vigas de aço e lajes de concreto armado visa explorar as melhores características de cada um dos elementos, gerando uma solução estrutural econômica e eficiente. Os conectores de cisalhamento, que são os dispositivos de união desses elementos, permitem a transferência do esforço cortante ao longo da estrutura. O presente trabalho trata-se de uma continuação do estudo realizado por Tamayo (2011), o qual desenvolveu um código computacional em linguagem Fortran 90, utilizando o método dos elementos finitos, que é capaz de representar estruturas de vigas mistas em análises de curta duração. A teoria da plasticidade associada com um algoritmo de retorno explícito para o concreto e aço foi empregada em um procedimento incremental iterativo. O presente trabalho visa incluir a análise de serviço no código elasto-plástico, ou seja, a consideração dos efeitos de longa duração que interferem na distribuição de tensões e deformações da estrutura. A teoria da solidificação proposta por Bazant e Prasannan (1988) foi empregada para analisar os efeitos devido à fluência do concreto. Para o cálculo da fluência empregou-se um modelo reológico baseado na cadeia de Kelvin em série. Usando conceitos da série de Dirichlet, os parâmetros desta cadeia foram obtidos através de uma aproximação por mínimos quadrados. Em conjunto com a teoria da solidificação, os modelos de fluência e retração, propostos pelo Comité Euro-International du Béton (1990), foram utilizados. O amolecimento do concreto foi adicionado ao modelo computacional. Para os conectores de cisalhamento foi testada uma nova formulação empregando uma rigidez secante. As tarefas de pré e pós processamento foram realizadas através do software GiD que auxiliou nas etapas de geração da geometria e malha de elementos finitos, confecção de arquivo de entrada, e visualização dos resultados. Exemplos testados experimentalmente foram empregados para validação do modelo numérico proposto. / Steel-concrete composite beams have been widely applied to both small and large civil works. The combined use of steel beams and reinforced concrete slabs aims to explore the best features of each one, creating an efficient structural solution with low cost. The shear connectors are the device joining the steel beam and concrete slab, allowing the transfer of shear along the structure. This work follows the research of Tamayo (2011) who developed a program in Fortran 90 language, using the finite element method, capable of representing composite beam structures in short time analyzes. The associated theory of plasticity with an explicit return algorithm for concrete and steel was used in an incremental iterative procedure. This study aims to include the service analysis into the code, which means to account for long-term effects that influence the stress and strain distribution in the structure. The solidification theory proposed by Bazant and Prasannan (1988) was used to examine the creep effects of concrete. For the creep calculation, a rheological model based on the Kelvin chain in series was employed. Using concepts of Dirichlet series, the chain parameters were obtained through a least squares approximation. Together with the solidification theory, the creep and shrinkage models proposed by the Comité Euro-International du Béton (1990) were used. The concrete softening was added to the computational model. A new formulation using secant stiffness was tested for the shear connectors modeling. The pre and post processing tasks were performed using the GiD software, which was used for geometry and finite element mesh generation, input file writing, and results viewing. Specimens tested experimentally were used for the validation of the proposed numerical model.