A method of predicting delamination in fibre-reinforced composite materials including several previously disregarded strength issues is presented. Thermal residual stresses, volume of stressed material, in-plane stresses and the hydrostatic stress in the polymer matrix are introduced and their influence on composite material strength discussed. These factors are then applied in a stress based method for predicting delamination which can deal with both unidirectional and general laminates. The results from a series of scaled unidirectional specimens designed to produce interlaminar tensile strength data are used to determine the strength parameters for the method. The method is shown to be effective in predicting failure in the fill-in region of two 'T'- piece specimen designs to within 14%. The failures were dominated by tension acting between fibres in large blocks of unidirectional material which had high thermal residual stresses and tensile hydrostatic stress due to constraint from the surrounding material. The method is also applied to a series of test pieces which used general laminates. The designs are based on sandwich panel sections and a tapered I-beam specimen. In the sandwich panel specimens, the edge closure sections were constructed using 0,90 and ±45° plies. Delamination occurred in a region of dropped plies and curvature making all the stress components important in producing accurate predictions, which are within 16% of the failure loads in testing. The tapered I-beam specimens were designed to delaminate in a doubly-curved laminate region of 90 and ±45° plies. The delamination predictions were within 13% of the first delamination loads found in testing. The method produced failure predictions which were all within 16% of the failure loads of the tested specimens. It is found that the local geometry of the delamination region is critical in determining the stress levels in the specimens and therefore their strength. Variations in the manufacture of such specimens and components is therefore clearly important in establishing the delamination loads of composite structures.

Heat exchangers and steam headers are at the heart of any boiler and are susceptible to a range of failures including tube leaks, ligament cracking, creep and fatigue. These common forms of header failure mechanisms can be exacerbated by local thermal stresses due to temperature and flow maldistribution at full and partial boiler load operations. The purpose of this project is to develop process models of the outlet stubbox header of a final superheater (FSH) heat exchanger in a 620MW coal-fired drum type boiler. The process models were used to assess the impact of steam flow and temperature distribution on the thermal stresses in the header material. The process models were developed using Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA). Thermocouples were installed at key locations on the stubbox headers to monitor metal temperatures and the measured metal temperatures served as boundary values and for validation of the CFD results. The thermocouple data was analysed for three different steady state boiler loads, namely full load, 80% load and 60% load. It showed that the temperature distribution across these headers was not uniform, with a maximum temperature difference across the outlet stubbox of 40℃ at full load and 43℃ at partial loads. Other relevant power plant data, such as steam pressure, was provided from the power plant's Distributed Control System (DCS) and was used as boundary conditions for the CFD models. The exact mass flow distribution across the inlet stubs of the outlet stubbox header was unknown and was estimated using a CFD model of the inlet stubbox header and steam mass flow values from power plant's DCS system. A CFD model was created for each of the three boiler loads at steady state conditions. The CFD results provided the metal temperature profile, internal steam temperature distribution and pressure distribution across the header. The CFD solid temperatures were validated using the thermocouple readings and found to be in agreement. The CFD results were exported to the FEA models, where specific displacement constraints for thermal expansion were utilised. The FEA models were used to assess the extent of thermal stresses due to thermal expansion only, as well as stresses due to thermal expansion combined with internal pressure. High local stresses were found at the borehole crotch corners of the rear outlet branch and inlet stubs. However, these are below 0.2% proof strength at elevated temperatures. The high local stresses thus did not result in local plastic deformation but contribute to exacerbate steady state failure mechanisms such as creep.

No description available.

The effect of laser power pattern on the temperature and thermal stress distributions in LED die bonding process is investigated in this work. The wavelength of 940nm diode laser source is used in this study. The laser light is focus on the back of an AlN substrate. The eutectic Au80Sn20 solder metallized between die and substrate is soldered by the heat conducted from the controlled laser power. The finite element package software-MSC. Marc is employed to simulate the laser soldering process. The thermal-elastic-plastic models of the solid elements are used. The temperature dependent material properties are applied to characterize the temperature variation effect during the die bonding. The measured temperature data have also been used to derive the absorption coefficient, conductivity, specific heat of AlN substrate and the convection coefficient in free convection via the inverse engineering process. A difference between the simulated and measured temperature can be kept in 10%. The temperature and thermal stress distributions during the die bonding process have been simulated and studied. The distributions of residual stress induced in this die bonding process have also been studied. The effects of different laser soldering parameters, e.g. focus shift, defocus, inclined angle, on the die bonding are also studied.

The main purpose of this research is to utilize the FEMLAB multiphysics software as to analyze the thermal stress of Cu/Diamond/Cu three-layered heat spreader device. The alteration of film thickness under different temperatures(allowing the device to increase from room temperature of 27¢XC to 100¢XC, 200¢XC and 300¢XC), with upper Cu layer of 2µm, altered middle diamond layer(20µm, 50µm 100µm), and lower Cu layer(100µm, 200µm, 300µm)(assuming that there is no residual stress produced after the manufacture of heat spreader device), is regarded as the conditional parameter of heat spreader device in analyzing the deformation rate and stress variation produced. After simulation of the research, it was found out that a maximum shear stress is attained under a fixed temperature load. And, when the film thickness is altered and under a fixed thick of Cu layer, the shear stress will become bigger due to the thickness of the diamond layer increases, when the diamond layer is 50-70µm, stress increases slowly; but it is considered to be the greatest effect when the heat transfer of diamond is at 100µm; thus selection of 70µm would be a better option in this paper suggestion, and that the alteration of the thickness of lower Cu layer will not cause great effect to max shear stress.) After stabilizing the thickness of upper Cu layer and middle diamond layer, the maximum deformation rate will become smaller when the thickness of lower Cu layer increases.

Abstract The thesis is aimed to analyze the flip chip in chip scale package (CSP) by finite element method incorporated with software ANSYS due to thermally cyclic loading. The coefficient of thermal expansion (CTE) of underfill and different mechanical properties of four kinds underfill-A, B, C, D and with/without metal cap are considered as parameters. The effects of above-mentioned parameters on package¡¦s displacement, strain and stress fields are studied. The results show that the maximum equivalent strain and stress take place at the interface between chip and underfill far away from the center of the whole package and on the top of the most outside solder bump in the solder joint. The larger the CTE of underfill is, the larger the maximum equivalent strain and stress are. Package with metal cap can reduce the displacement to almost half or more of that without cap, but increase the values of maximum equivalent strain and stress. No matter with metal cap or not, the underfill D is the best choice. Hence, the underfill material properties possess lower CTE and larger Young¡¦s modulus than those of solder bump.

TEIXEIRA, Marcílio Costa. Comportamento e desempenho de novilhas pardo-suiça e girolanda em sistema de pastejo rotacionado irrigado no semi-árido nordestino. 2005. 67 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Zootecnia, Fortaleza-CE, 2005 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-05T12:36:47Z No. of bitstreams: 1 2005_dis_mcteixeira.pdf: 299201 bytes, checksum: 50de5c2f75387755b3dbdee039a28647 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-05T12:38:42Z (GMT) No. of bitstreams: 1 2005_dis_mcteixeira.pdf: 299201 bytes, checksum: 50de5c2f75387755b3dbdee039a28647 (MD5) / Made available in DSpace on 2016-08-05T12:38:43Z (GMT). No. of bitstreams: 1 2005_dis_mcteixeira.pdf: 299201 bytes, checksum: 50de5c2f75387755b3dbdee039a28647 (MD5) Previous issue date: 2005 / The experiment took place at the experimental station of Vale do Curu (FEVC) of the Federal University of Ceará. The station is located in the irrigated area of the Pentecoste county which is located in the semi-arid region of Ceará. Heifers of Brown-Swiss an Girolanda were kept under a continuous grazing system with irrigated pasture of Panicum maximum (CV): Colonião. Two treatments were applied: mineral salt (SM) and mineral salt plus protein (SMP). The body wight and corporal measurement (thorax perimeter, hip height, and length of mammary gland) were made concomitantly and every 15 days. The samples of pasture and simulated grazing were analyzed for dry matter, brute protein,neutral detergent fiber, and acid detergent fiber prior to the animal entrance into the pasture.The experimental units were distributed in a complete randomized block design (CRBD)with ten heifers per treatment. The animals showed good average weight gain (1,029 kg/animal/day), no statistical difference was observed between the treatments even with a higher intake of SMP. The corporal measures showed little variation between pasture fields and between cycles that could be attributed to irregular manure deposition. The grass available for the animal had good protein and fiber contents. The activity was economically stable, with possibility of expansion and of being self sustainable for a long time. The post wean producer in these areas could be demanded for this phase of growth by more specialized producers. / O experimento foi conduzido na Fazenda Experimental Vale do Curu (FEVC) da Universidade Federal do Ceará (UFC), localizada no perímetro irrigado do município de Pentecoste, região semi-árida do Ceará. Utilizou-se novilhas da raça Parda-Suíça e Girolanda, que foram mantidas em sistema de pastejo irrigado continuo de capim Colonião (Panicum maximum, Jacq), sendo distribuídos em dois tratamentos: sal mineral proteinado (SMP) e sal mineral (SM). As pesagens e mensurações alométricas (perímetro torácico, altura de cernelha e comprimento da glândula mamária) foram realizadas quinzenalmente. As coletas do pasto e o pastejo simulado, para análise bromatológica (matéria seca, proteína bruta, fibra em detergente neutro e fibra em detergente ácido) eram feitas sempre antes e no momento da entrada dos animais no piquete, respectivamente. Os animais foram distribuídos em um delineamento inteiramente casualizado com dez novilhas por tratamento. Os animais apresentaram um bom ganho médio de peso (1,029 kg/animal/dia), não havendo diferença entre os tratamentos, mesmo com o maior consumo de suplemento no tratamento SMP. A análise bromatológica mostrou que houve pouca variação entre piquetes e entre ciclos, atribuídas a irregularidade na adubação a lanço. A atividade mostrou-se economicamente estável, com possibilidade de expansão e de se manter por longo prazo. A recria em tais áreas poderá estimular a terceirização desta fase por produtores mais especializados.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O experimento foi conduzido na Fazenda Experimental Vale do Curu (FEVC) da Universidade Federal do Cearà (UFC), localizada no perÃmetro irrigado do municÃpio de Pentecoste, regiÃo semi-Ãrida do CearÃ. Utilizou-se novilhas da raÃa Parda-SuÃÃa e Girolanda, que foram mantidas em sistema de pastejo irrigado continuo de capim ColoniÃo (Panicum maximum, Jacq), sendo distribuÃdos em dois tratamentos: sal mineral proteinado (SMP) e sal mineral (SM). As pesagens e mensuraÃÃes alomÃtricas (perÃmetro torÃcico, altura de cernelha e comprimento da glÃndula mamÃria) foram realizadas quinzenalmente. As coletas do pasto e o pastejo simulado, para anÃlise bromatolÃgica (matÃria seca, proteÃna bruta, fibra em detergente neutro e fibra em detergente Ãcido) eram feitas sempre antes e no momento da entrada dos animais no piquete, respectivamente. Os animais foram distribuÃdos em um delineamento inteiramente casualizado com dez novilhas por tratamento. Os animais apresentaram um bom ganho mÃdio de peso (1,029 kg/animal/dia), nÃo havendo diferenÃa entre os tratamentos, mesmo com o maior consumo de suplemento no tratamento SMP. A anÃlise bromatolÃgica mostrou que houve pouca variaÃÃo entre piquetes e entre ciclos, atribuÃdas a irregularidade na adubaÃÃo a lanÃo. A atividade mostrou-se economicamente estÃvel, com possibilidade de expansÃo e de se manter por longo prazo. A recria em tais Ãreas poderà estimular a terceirizaÃÃo desta fase por produtores mais especializados. / The experiment took place at the experimental station of Vale do Curu (FEVC) of the Federal University of CearÃ. The station is located in the irrigated area of the Pentecoste county which is located in the semi-arid region of CearÃ. Heifers of Brown-Swiss an Girolanda were kept under a continuous grazing system with irrigated pasture of Panicum maximum (CV): ColoniÃo. Two treatments were applied: mineral salt (SM) and mineral salt plus protein (SMP). The body wight and corporal measurement (thorax perimeter, hip height, and length of mammary gland) were made concomitantly and every 15 days. The samples of pasture and simulated grazing were analyzed for dry matter, brute protein,neutral detergent fiber, and acid detergent fiber prior to the animal entrance into the pasture.The experimental units were distributed in a complete randomized block design (CRBD)with ten heifers per treatment. The animals showed good average weight gain (1,029 kg/animal/day), no statistical difference was observed between the treatments even with a higher intake of SMP. The corporal measures showed little variation between pasture fields and between cycles that could be attributed to irregular manure deposition. The grass available for the animal had good protein and fiber contents. The activity was economically stable, with possibility of expansion and of being self sustainable for a long time. The post wean producer in these areas could be demanded for this phase of growth by more specialized producers.

As ocean temperatures continue to rise, the effect of temperature on marine organisms becomes highly relevant. The Red Sea is the warmest sea and is rapidly warming with current surface temperatures (28 – 34 °C) already exceeding those of most tropical systems. This has major consequences for organisms that may already find themselves at their thermal limits. The aim of this project was to define the thermal limits and thresholds of certain Red Sea species. Firstly, to better understand the thermal regimes of the Red Sea, we looked at decadal trends in maximum sea surface temperature across the basin. Then, we tested the thermal capacities of Red Sea mangroves and zooplankton, two key ecological groups, by performing thermal stress experiments in the laboratory. We found that the Red Sea basin is warming faster than the global average (0.17 °C decade-1), the thermal limit of mangrove propagules is between 33 and 35 °C, and the limits among the most common zooplankton groups range from 30 to 36 °C. This project gives us a better understanding of how organisms respond to extreme temperatures and how they may be affected in a future, warmer, ocean.

Orientador: Lindsay Unno Gimenes / Coorientador: Alexandre Rossetto Garcia / Coorientador: José Ricardo Macedo Pezzopane / Resumo: O uso do sistema silvipastoril tem sido sugerido como uma alternativa para aumentar a produtividade e sustentabilidade da pecuária, além de oferecer maior conforto térmico aos animais criados em áreas de clima tropical. No entanto, existem diversas dúvidas sobre os impactos de sua adoção quanto a aspectos reprodutivos. Nesta tese, avaliou-se o impacto do sistema silvipastoril (SP) comparado ao sistema de pastejo rotacionado intensivo (RI)sobre o conforto térmico (CT) de fêmeas bovinas da raça Canchim, caracterizando o efeito do microclima desses sistemas sobre variáveis fisiológicas (exp. 1 e 2) e sobre o perfil metabólico e a produção in vitro de embriões (PIVE; exp. 2). Em ambos, foi realizada monitoração microclimática e calculados o índice de temperatura de globo úmido (ITGU) e a carga térmica radiante (CTR). Foram também aferidas, as temperaturas: retal (TR), com o uso de termômetro de mercúrio e de superfície corpórea de linha do dorso (TD) por meio de câmera termográfica, além disso, peso vivo (PV;kg), ECC, a estimativa da ingestão de matéria seca (IMS) e colheita de sangue para dosagem de cortisol foram realizados. No experimento 1, 32 novilhas com idade de 16,2 ± 0,05 e 249,8 ± 1,75 kg de peso vivo, foram também avaliadas quanto a frequência respiratória (FR; mpm) e frequência cardíaca (FC; bpm). No experimento 2, 18 vacas com média de 26,2 ± 2,2 dias pós-parto, 41,2 ± 0,6 meses de idade e 477,0 ± 12,0 de peso vivo (kg), passaram por avaliação ultrassonográfica, e fo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Silvopastoral systems has been suggested as an alternative to increase productivity and sustainability in livestock production. In addition, can offer thermal comfort to animals managed in tropical climate areas. However, there are several doubts about the impacts on reproductive performance when using these systems. In this thesis, the impact of use of silvopastoral system (SP) in compare to the intensive rotational grazing (IR) system on the thermal comfort (TC) of Canchim cattle, was evaluated, characterizing the effect of the microclimate of these systems on physiological variables (experiment #1 and #2) and on the metabolic profile and the in vitro production of embryos (PIV) (experiment#2). In both, microclimatic monitoring was performed and the black globe humidity index (ITGU) and radiant heat load (CTR) were calculated. Were also monitored rectal temperature (RT), with the use of a mercury thermometer and body surface temperature of back line (BLT) using thermographic camera. Heifers and cows were evaluated monthly to body weight (BW; kg), BCS measurement, dry matter intake (DMI; kg DM/d) and to collect blood samples for cortisol assay. In experiment 1, 32 heifers (16.2 ± 0.05 mo of age; 249.8 ± 1.75 kg of BW) were also evaluated to respiratory rate (RR; mpm) and heart rate (HR; bpm). In experiment 2, 18 cows (26.2 ± 2.2 d postpartum; 41.2 ± 0.6 mo of age; 477.0 ± 12.0 kg of BW) were evaluated by ovarian ultrasonography, and, were submitted to ultrasound-guided folli... (Complete abstract click electronic access below) / Doutor