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Made available in DSpace on 2016-12-08T16:24:16Z (GMT). No. of bitstreams: 1 PGCA14MA126.pdf: 1502489 bytes, checksum: 114ec2bccc4079c0c854d6aabdb2add0 (MD5) Previous issue date: 2014-02-25 / The study aimed to evaluate the health, zootechnical and economic behavior of pigs housed in the "wean-to-finish" system (WF) compared to the conventional production system. Two groups of pigs from the same sow farms, born and weaned in the same week, were evaluated. One group was housed in a conventional production system and the other in a WF adapted barn, both in collective pens. After the end of the nursery phase part of the WF group was transferred and housed in a conventional barn and replaced by part of the conventional group (CC), forming four groups (WF ,CC1 ,CC2 and CC3). For analysis of production was calculated the average daily feed intake (DFI), average daily gain (ADG) and feed conversion ratio (FCR). For economic analysis were determined the cost of ration per kilogram of live weight gain, the index of economic efficiency (IEE) and cost index (CI) . The health examination consisted of clinical monitoring (incidence of diarrhea, cough and sneezing), laboratory monitoring (necropsy and sample collection for histology and bacteriology) and slaughter, with the rates of pneumonia (IPP), atrophic rhinitis (RAP), kidney and liver lesions. Data were subjected to analysis of variance using the SAS statistical package, previously tested for normality of the residuals using the Shapiro-Wilk test, and the means of groups were compared by the Tukey test (5 %). Mortality was low in all groups, with the main reason of death the circovirosis. The rates of diarrhea were also not significant, with the highest incidence in nursery phase for the WF group. During the grow/finish the lowest index was of the WF, who not suffered transfer. Data from cough and sneezing were also not considered significant in all stages of review. In the slaughter-house the highest rates of RAP and IPP were of the WF group. The highest production rates for final body weight, ADG and CDR in nursery phase were of the WF group, but feed conversion ratio was better in CC. During the grow/finish the WF and CC3 group ended with similar final body weights and higher than the other groups. The ADG and FCR were equal to WF, CC1 and CC3 groups. In the economic aspect WF group had the lowest costs, with a difference of up to R$ 0.09 per kilogram of live weight gain compared to the other groups. The results of productive performance mainly linked with the economic aspect, shows that WF system can be a viable alternative for the pork industry / O trabalho teve como objetivo avaliar o comportamento zootécnico, econômico e sanitário de suínos alojados no sistema wean-to-finish (WF) em comparação ao sistema convencional de produção. Foram avaliados dois grupos de suínos provenientes das mesmas unidades produtoras de leitões, nascidos e desmamados na mesma semana. Um grupo foi alojado em um sistema convencional de produção e o outro em um galpão WF adaptado, ambos em baias coletivas. Após o termino da fase de creche parte do grupo WF foi transferido e alojado em um galpão convencional, e substituído por parte do grupo convencional (CC), formando-se quatro grupos (WF, CC1, CC2 e CC3). Para análise de produção foi calculados o consumo médio diário de ração (CDR), o ganho médio de peso diário (GPD) e a conversão alimentar (CA). Para análise econômica foram determinados o custo em ração por quilograma de ganho de peso vivo, o índice de eficiência econômica (IEE) e o índice de custo (IC). A análise sanitária consistiu em monitoria clínica (incidência de diarreia, tosse e espirro), monitoria laboratorial (necropsia com coleta de material para histologia e bacteriologia) e de abate, com os índices de pneumonia (IPP), rinite atrófica (RAP), lesões renais e hepáticas. Os dados foram submetidos à análise de variância utilizando-se o pacote estatístico SAS, previamente testados para normalidade dos resíduos pelo teste de Shapiro-Wilk, e as médias dos grupos comparadas pelo teste de Tukey (5%). A mortalidade foi baixa em todos os grupos, tendo como principal causa mortis a circovirose. Os índices de diarreia também não foram significativos, com maior incidência na fase de creche para o grupo WF. Nas fases de crescimento e terminação o índice mais baixo foi do WF que não sofreu transferência. Os dados de tosse e espirro também não foram considerados significativos em todas as fases de avaliação. No frigorífico os maiores índices de RAP e IPP foram do grupo WF. Os maiores índices produtivos para peso médio e GPD e CDR finais na fase de creche foram do grupo WF, porém a conversão alimentar do CC foi melhor. Nas fases de crescimento e terminação o grupo WF e o CC3 terminaram com peso médio final semelhante e maiores que os outros grupos. O GPD e a CA foram iguais para os grupos WF, CC1 e CC3. No aspecto econômico o grupo WF apresentou os menores custos, com diferença de até R$ 0,09 por quilograma de ganho de peso vivo em comparação aos demais grupos. Os resultados do desempenho produtivo associados principalmente ao aspecto econômico ajudaram a concluir que o sistema WF é uma alternativa viável dentro da cadeia produtiva de suínos

Electrochemical machining (ECM) is a non-conventional manufacturing process, which uses electrochemical dissolution to shape any conductive metal regardless of its mechanical properties and without leaving behind residual stresses or tool wear. Therefore, ECM can be an alternative for machining difficult-to-cut materials, complex geometries, and materials with improved characteristics, such as strength, heat-resistance or corrosion-resistance. Notwithstanding its great potential as a shaping tool, the ECM process is still not fully characterised and its research is an on-going process. Various phenomena are involved in ECM, e.g. electrodynamics, mass transfer, heat transfer, fluid dynamics and electrochemistry, which occur in parallel and this can lead to a different material dissolution rate at each point of the workpiece surface. This makes difficult an accurate prediction of the final workpiece geometry. This problem was addressed in the first part of the present thesis by developing a simulation model of the ECM process in a two-dimensional (2D) environment. A finite element analysis (FEA) package, COMSOL multiphysics® was used for this purpose due to its capacity to handle the diverse phenomena involved in ECM and couple them into a single solution. Experimental tests were carried out by applying ECM on stainless steel 316 (SS316) samples. This work was done in collaboration with pECM Systems Ltd® from Barnsley, UK. The interest of studying ECM on stainless steels (SS) resides on the fact that the application of ECM on SS typically results in various different surface finishes. The chromium in SS alloys usually induces the formation of a protective oxide film that prevents further corrosion of the alloy, giving the metal the special characteristic of corrosion resistance. This oxide film has low electrical conductivity; hence normal anodic dissolution often cannot proceed without oxide breakdown. Partial breakdown of the oxide film often occurs, which causes pits on the surface or a non-uniform surface finish. Therefore the role of the ECM machining parameters, such as interelectrode gap, voltage, electrolyte flow rate, and electrolyte inlet temperature, on the achievement of a uniform oxide film breakdown was evaluated in this work. Experimental results show that the resulting surface finish is highly influenced by the over-potential and current density, and by the characteristics of the electrolyte, flow rate and conductivity. The complexity of experimentally controlling these parameters emphasised the need for the development of a computational model that allows the simulation of the ECM process in full. The simulation of ECM in a three-dimensional (3D) environment is crucial to understand the behaviour of the ECM process in the real world. In a 3D model, information that was not visible before can be observed and a more detailed realistic solution can be achieved. Hence, in this work a computer aided design (CAD) software was used to construct a 3D geometry, which was imported to COMSOL Multiphysics® to simulate the ECM process, but this time in a 3D environment. This enhanced simulation model includes fluid dynamics, heat transfer, mass transfer, electrodynamics and electrochemistry, and has the novelty that an accurate computational simulation of the ECM process can be carry out a priori the experimental tests and allows the extraction of enough information from the ECM process in order to predict the workpiece final shape and surface finish. Moreover, this simulation model can be applied to diverse materials and electrolytes by modifying the input ECM parameters.

Bulk forming and cutting are widely used to shape metals in industrial production. Bulk forming is characterized by large strains, extensive plastic deformation and large surface expansions. Cutting is characterized by high speeds, high pressures and high temperatures. The prevailing conditions during these processes lead to transfer of work material to tools. In bulk forming this is a significant problem. The transferred work material is hardened and becomes harder than the work material, causing galling. This leads to high friction and high forming forces, bad surface finish of the formed products and significant difficulties to produce complicated geometries. In cutting, transfer of work material can be desired for protection of the tool surface. However, the transfer film has to be of the correct type to provide a stable and predictive behaviour during operation. In this thesis the influence from tool material and surface treatment on work material transfer has been studied for both applications, with the use of simplified laboratory test methods followed by extensive surface studies. Both the tendency to, appearance of and chemical composition of work material transfer is evaluated. The results are compared with real industrial examples, to ensure that the correct mechanisms are mimicked. In forming, the problems arise when poor lubrication prevails, due to high forming forces or large surface expansions. The transfer of work material can then be avoided with the use of a galling resistant coating, offering low adhesion. However, the coating has to be as smooth as possible, to avoid activation of the work material and subsequent transfer. In cutting, the desired transfer film can be obtained by choosing the correct cutting parameters. The geometry and material of the fabricated component is often predetermined, setting the general cutting conditions, but the cutting speed influences the formation of the transfer film. Too low speed or too high speed leads to an unstable cutting process and poor surface finish of the piece. The speed intervals for each mechanism are partly determined by the tool material and thus by the tool coating.

This study presents a hybrid concurrent programming model combining the previously developed Fork-Join model (FJM) and Actor model (AM). With the advent of multi-core computers, there is a renewed interest in programming models that reduce the burden of reasoning about and writing efficient concurrent programs. The proposed hybrid model shows how the divide-and-conquer approach of the FJM and the no-shared mutable state and event-driven philosophy of the AM can be combined to solve certain classes of problems more efficiently and productively than either of the aforementioned models individually. The hybrid model adds actor creation and coordination to into the FJM, while also enabling parallelization within actors. This study uses the Habanero-Java and Scala programming languages as the base for the FJM and AM respectively, and provides an implementation of the hybrid model as an extension of the Scala language called Habanero-Scala. The hybrid model adds to the foundations of parallel programs, and to the tools available for the programmer to aid in productivity and performance while developing parallel software.

The design of an uncemented hip arthroplasty implant affects its long-term survival. Characteristics such as the form and the finish of the implant are crucial in order to achieve the best possible conditions for long-term implant survival. In this thesis we hypothesized that different shapes of stems and cups used in primary and revision total hip arthroplasty (THA), and their finish with hydroxyapatite (HA) coating affect implant stability and thus long-term survival. In 2 prospective cohort studies the clinical outcome, the stability measured with radiostereometric analysis (RSA), and the periprosthetic changes in bone mineral density (BMD) measured with dual-energy x-ray absorptiometry (DXA) were investigated in 2 uncemented THA implants – the CFP stem and the TOP cup. In 3 register studies the effect of HA coating on uncemented THA implants used in primary and revision arthroplasty was investigated. Both implants investigated in the prospective cohort studies showed an excellent short-term clinical outcome with good primary stability, but neither their novel form nor the finish with HA protected the implants from the proximal periprosthetic demineralization that usually occurs around other uncemented THA implants. The register studies revealed that HA coating on cups used in primary and revision THA is a risk factor for subsequent revision of the implant. The use of HA coating on the stem in primary THA did not affect long-term survival. Additionally, the shape of an implant plays a crucial role for implant stability and survival. In conclusion, this thesis highlights that the finish of implants with HA coating does not prevent periprosthetic proximal femoral bone loss and can even enhance the risk of revision of both primary and secondary cups. Importantly, the shape of uncemented THA implants affect their stability, showing that the implant form is a crucial factor for the long-term survival.

The compatibility properties of some contemporary finish coats together with their complementary layers used in insulated exterior walls were examined in terms of water vapour permeability and modulus of elasticity. Basic physical and mechanical properties of some synthetic-, cement- and polymer-based external finish coats were analyzed in laboratory. Some additional samples, complementing the wall section, were also examined for their water vapour permeability. Results showed that the finish coats were high vapour permeable although they had high resistance to water vapour permeation, which was achieved by their application in thin layers. Cement-based undercoats were found to be medium permeable. The application of primer and/or paint was found to decrease the permeability of finish coats in different ranges. Thermal insulation layer was found to interrupt water vapour flow considerably. Among polystyrene- and mineral-wool-based thermal insulation boards, rockwool was recommended as the insulation layer due to its medium vapour permeability. In conclusion, walls insulated externally with rockwool boards and plastered with polymer-based finish coat, FC8ACB or synthetic-based finish coat FC3SB were found to be the most proper combination in terms of breathing and thermal resistance capabilities. All finish coats seemed to have sufficient strength and except the synthetic-based finish coat, FC2SB, they seemed to be compatible with each other and with the masonry in terms of their Emod values. Further studies were recommended on some other compatibility properties of finishing systems, such as thermal and moisture dilatation properties, and on the relation between the resistance to water vapour permeation and water permeability.

Unlike straight turning, the effective cutting conditions and tool geometry in contour turning operations are changing with changing workpiece profile. This causes a wide variation in machining performance such as chip flow and chip breakability during the operation. This thesis presents a new methodology for optimizing the machining performance, namely, chip breakability and surface roughness in contour finish turning operations. First, a computer program to calculate the effective cutting conditions and tool geometry along the contour workpiece profile is developed. Second, a methodology to predict the chip side-flow for complex grooved tool inserts is formulated and integrated in the current predictive model for contour turning operations. Third, experimental databases are established and numerical data interpolation is applied to predict the cutting forces, chip shape and size, and surface roughness for 1045 steel work material. Finally, based on the machining performance predictions, a new optimization program is developed to determine the optimum cutting conditions in contour finish turning operations.

Este trabalho apresenta resultados de testes com processo de usinagem para diferentes ferramentas de torneamento. Foram realizados ensaios para avaliar a diferença de comportamento quantoa esforçosde cortee acabamentosuperficialem operaçãode torneamento para um mesmo tipo de ferramenta, com variação na superfície de saída, sendo uma com quebra cavaco com outra de superfície de saída lisa. O material usinado foi aço ao carbono 1045 recozido, testado para duas diferentes velocidades, variando-se também a profundidade de corte e avanço para cada ensaio. Os testes foram executados em um torno mecânico convencional, onde as variáveis do processo foram coletadas com um sistema de aquisição de dados, através de um dinamômetro piezoelétrico para avaliação das forças de corte e um rugosímetro portátil para medida da rugas idade superficial. Observou-se nos resultados, uma forte diminuição dos esforços quando aplicada a ferramenta sinuosa com quebra-cavaco, bem como melhoria nas características do cavaco. Em relação à rugas idade superficial houve uma pequena melhora quando utilizada a ferramenta com superfície de saída lisa, situação decorrente das condições de remoção do cavaco. / This wark presents the results af machiningpracess tests with different turning tools. Tests were done to evaluate behaviors differenceson cutting efforts and surface finishing in turning operations to a same type of tool, with a variation on rake face, where one had a chipbreaker groove and the other are flat. The machining material was 1045 annealed carbon steel, tested to two different cutting speeds, changing also the depth of cut and the feed rate for each case. The tests were done in a conventionallathe, where the process variances were collected by a data acquisition system, through a piezoelectric dynamometer to evaluate the cut efforts and a portable rugosimeter to measure the surface roughness. The results show a strong reduction of the efforts when grooved tools with chip-breaker were applied as well an improvement on the chip characteristics. In relation to the surface roughness, it was observed a slight improvement when the tlat tool was used, because ofthe conditions of chip remova!.