985 resultados para Car body structures


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1. Little is known on the occurrence and magnitude of faster than normal (catch-up) growth in response to periods of undernutrition in the wild, and the extent to which different body structures compensate and over what timescales is poorly understood. 2. We investigated catch-up growth in nestling Alpine Swifts, Apus melba, by comparing nestling growth trajectories in response to a naturally occurring 1-week period of inclement weather and undernutrition with growth of nestlings reared in a good year. 3. In response to undernutrition, nestlings exhibited a hierarchy of tissues preservation and compensation, with body mass being restored quickly after the end of the period of undernutrition, acceleration of skeletal growth occurring later in development, and compensation in wing length occurring mostly due to a prolongation of growth and delayed fledging. 4. The effect of undernutrition and subsequent catch-up growth was age-dependent, with older nestlings being more resilient to undernutrition, and in turn having less need to compensate later in the development. 5. This shows that young in a free-living bird population can compensate in body mass and body size for a naturally occurring period of undernutrition, and that the timing and extent of compensation varies with age and between body structures.

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Background, aim, and scope A coupled Life Cycle Costing and life cycle assessment has been performed for car-bodies of the Korean Tilting Train eXpress (TTX) project using European and Korean databases, with the objective of assessing environmental and cost performance to aid materials and process selection. More specifically, the potential of polymer composite car-body structures for the Korean Tilting Train eXpress (TTX) has been investigated. Materials and methods This assessment includes the cost of both carriage manufacturing and use phases, coupled with the life cycle environmental impacts of all stages from raw material production, through carriage manufacture and use, to end-of-life scenarios. Metallic carriages were compared with two composite options: hybrid steel-composite and full-composite carriages. The total planned production for this regional Korean train was 440 cars, with an annual production volume of 80 cars. Results and discussion The coupled analyses were used to generate plots of cost versus energy consumption and environmental impacts. The results show that the raw material and manufacturing phase costs are approximately half of the total life cycle costs, whilst their environmental impact is relatively insignificant (3-8%). The use phase of the car-body has the largest environmental impact for all scenarios, with near negligible contributions from the other phases. Since steel rail carriages weigh more (27-51%), the use phase cost is correspondingly higher, resulting in both the greatest environmental impact and the highest life cycle cost. Compared to the steel scenario, the hybrid composite variant has a lower life cycle cost (16%) and a lower environmental impact (26%). Though the full composite rail carriage may have the highest manufacturing cost, it results in the lowest total life cycle costs and lowest environmental impacts. Conclusions and recommendations This coupled cost and life cycle assessment showed that the full composite variant was the optimum solution. This case study showed that coupling of technical cost models with life cycle assessment offers an efficient route to accurately evaluate economic and environmental performance in a consistent way.

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The developments in materials over the last decade have been considerable within the automotive industry, being one of the leaders in innovative product applications. Sustainable product development of an automotive structure requires a balanced approach towards technological, economical and ecological aspects. The introduction of new materials and processes is dependent on satisfying different factors. Competitive and legislative pressures, creating the need for change, affect these factors considerably. The process, direction and speed of change are often reactive. Current paper shows the application of aluminium alloys, for the use in the bottom structure of a car to face the problem for the weight of the entire bottom structure under static load conditions, including stiffness, strength and buckling constraints. In addition to minimized mass and materials' price, the assessment of an environmental impact of materials-candidates during the entire life cycle of the structure is considered.

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Neste trabalho aborda-se o desenvolvimento da carroçaria do Veículo Eléctrico Ecológico – VEECO recorrendo a tecnologias assistidas por computador. Devido à impossibilidade de abranger toda a temática das tecnologias assistidas por computador, associadas ao desenvolvimento de uma carroçaria automóvel, o foco deste trabalho assenta no processo de obtenção de um modelo digital válido e no estudo do desempenho aerodinâmico da carroçaria. A existência de um modelo digital válido é a base de qualquer processo de desenvolvimento associado a tecnologias assistidas por computador. Neste sentido, numa primeira etapa, foram aplicadas e desenvolvidas técnicas e metodologias que permitem o desenvolvimento de uma carroçaria desde a sua fase de “design” até à obtenção de um modelo digital CAD. Estas abrangem a conversão e importação de dados, a realização de engenharia inversa, a construção/reconstrução CAD em CATIA V5 e a preparação/correcção de modelos CAD para a análise numérica. Numa segunda etapa realizou-se o estudo da aerodinâmica exterior da carroçaria, recorrendo à ferramenta de análise computacional de fluidos (CFD) Flow Simulation da CosmosFloworks integrado no programa SolidWorks 2010. Associado à temática do estudo aerodinâmico e devido à elevada importância da validação dos resultados numéricos por meio de dados experimentais, foi realizado o estudo de análise dimensional que permite a realização de ensaios experimentais à escala, bem como a análise dos resultados experimentais obtidos.

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Dissertation presented to obrain the Ph.D degree in Biology. Developmental Biology

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The Finite Element Method is a well-known technique, being extensively applied in different areas. Studies using the Finite Element Method (FEM) are targeted to improve cardiac ablation procedures. For such simulations, the finite element meshes should consider the size and histological features of the target structures. However, it is possible to verify that some methods or tools used to generate meshes of human body structures are still limited, due to nondetailed models, nontrivial preprocessing, or mainly limitation in the use condition. In this paper, alternatives are demonstrated to solid modeling and automatic generation of highly refined tetrahedral meshes, with quality compatible with other studies focused on mesh generation. The innovations presented here are strategies to integrate Open Source Software (OSS). The chosen techniques and strategies are presented and discussed, considering cardiac structures as a first application context. © 2013 E. Pavarino et al.

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The door-closing process can reinforce the impression of a solid, rock-proof, car body or of a rather cheap, flimsy vehicle. As there are no real prototypes during rubber profile bidding-out stages, engineers need to carry out non-linear numerical simulations that involve complex phenomena as well as static and dynamic loads for several profile candidates. This paper presents a structured virtual design tool based on FEM, including constitutive laws and incompressibility constraints allowing to predict more realistically the final closing forces and even to estimate sealing overpressure as an additional guarantee of noise insulation. Comparisons with results of physical tests are performed.

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Scanning force microscopy was used to image rat basophilic leukemia (RBL-2H3) cell surfaces under different stimulation conditions that either permit or inhibit secretion. Cross-linking the surface IgE receptors with dinitrophenol-conjugated bovine serum albumin initiates secretion in RBL cells with concomitant spreading of the cell body. Structures at the cell surface approximately 1.5 microns in diameter relate to secretion both spatially and temporally. The position of these surface pits and their sizes suggest that they may be related to the dense-core granules positioned along the cytoskeletal filaments in detergent-extracted, unactivated RBL cell processes. Topographic scanning force microscopy images of RBL cell surfaces at 2, 5, and 35 min after activation show that these structures persist and change in cross-sectional profile with time after activation. These structures may be related to the membrane retrieval mechanism of cells after intense stimulation.

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The molecular mechanism of how insects recognize intruding microorganisms and parasites and distinguish them from own body structures is not well known. We explored evolutionary adaptations in an insect parasitoid host interaction to identify components that interfere with the recognition of foreign objects and cellular encapsulation. Because some parasitoids provide protection for the developing wasp in the absence of an overt suppression of the insect host defense, we analyzed the surface of eggs and symbiotic viruses for protective properties. Here we report on the molecular cloning of a 32-kDa protein (Crp32) that is one of the major protective components. It is produced in the calyx cells of the female wasp ovaries and attached to the surface of the egg and other particles including polydnaviruses. The recombinant protein confers protection to coated objects in a cellular encapsulation assay suggesting that a layer of Crp32 may prevent cellular encapsulation reactions by a local inactivation of the host defense system.

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The adoption of faster modes of transportation (mainly the private car) has changed profoundly the spatial organisation of cities. The increase in distance covered due to increased speed of travel and to urban sprawl leads to an increase in energy consumption, being the transportation sector a huge consumer responsible for 61.5% of total world oil consumption and a global final energy consumption of 31.6% in EU-27 (2007). Due to unsustainable transportation conditions, many cities suffer from congestion and various other traffic problems. Such situations get worse with solutions mostly seen in the development of new infrastructure for motorized modes of transportation, and construction of car parking structures. The bicycle, considered the most efficient among all modes of transportation including walking, is a travel mode that can be adopted in most cities contributing for urban sustainability given the associated environmental, economic and social advantages. In many nations a large number of policy initiatives have focused on discouraging the use of private cars, encouraging the use of sustainable modes of transportation, like public transportation and other forms such as bicycling. Given the importance of developing initiatives that favour the use of bicycle as an urban transportation mode, an analysis of city suitability, including distances and slopes of street network, is crucial in order to help decision-makers to plan the city for bicycle. In this research Geographical Information Systems (GIS) technology was used for this purpose and some results are presented concerning the city of Coimbra.

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Os componentes obtidos através da conformação plástica de chapas têm uma grande importância, tanto na etapa de concepção do produto como na etapa de produção na indústria automóvel. Isto comprova-se pelo facto de, em média, cada automóvel integrar cerca de 500 componentes estampados para construir o chassis e a carroçaria [Alves 2003]. Deste total de componentes, 50 são de grandes dimensões (portas, tejadilho, painéis inferior e laterais, entre outros) e necessitam, em média, de cinco ferramentas para o seu fabrico, sendo o custo estimado para cada ferramenta de 230 000 € [Col 2000, Alves 2003]. Para além da indústria automóvel, a conformação plástica de chapas metálicas é um processo tecnológico presente nas indústrias relativas à aeroespacial, petrolífera, decoração, alimentar, entre outras. Do ponto de vista do enquadramento económico, cerca de 20% do custo total de um automóvel novo é devido à incorporação de componentes metálicos estampados. [Alves 2003]. A pressão do “Mercado Global” faz com que os custos relativos à matéria-prima, energia e mão-de-obra sejam uma constante em termos de redução do seu impacte no orçamento das empresas fornecedoras destes produtos. É neste contexto que surge a necessidade da realização deste estudo de Benchmark de Softwares, tornando-se bastante importante, quer ao nível da competitividade industrial, quer ao nível da inovação para novos produtos. A análise por elementos finitos desempenha um papel primordial no tryout virtual e otimização das ferramentas e processos de conformação plástica. Os objetivos principais deste estudo de simulação numérica são a identificação e comparação dos resultados obtidos pelo AUTOFORM e pelo PAMSTAMP, para cada uma das variáveis identificadas como as mais influentes na robustez dos processos de estampagem de chapa metálica. Estas variáveis identificadas são: consumo de material (Draw-in) após conformação; forças de conformação; valores de variação de espessura e dos valores de extensão e resultados de Springback. Os resultados obtidos são comparados com os resultados experimentais e, desta forma, avalia-se a capacidade inovadora e a eficácia de cada um dos softwares, obtendo-se assim, uma orientação mais real para o software mais indicado aos objetivos impostos pela indústria automóvel. Para este efeito, a indústria automóvel, como maior impulsionador e motor da investigação na área da simulação numérica aplicada aos processos de estampagem, tem aderido em peso ao Benchmarking. Um exemplo disto, é o que acontece nas conferências Numisheet. O Benchmark #2 da conferência Numisheet 2008 é analisado pormenorizadamente e os resultados numéricos e experimentais são comparados e apresentados. Dois materiais distintos (aço HC260LAD e liga de alumínio AC170), assim como três modelos com geometrias diferentes (com e sem freios) são apresentados neste relatório. Com vista à redução dos ciclos tentativa-erro, tem-se adotado ciclos virtuais ou numéricos e tem-se incrementado a interatividade entre as fases de concepção e projeto, num conceito muito próprio, mas cada vez mais abrangente, denominado “produção virtual”. É nesta filosofia que se insere a simulação numérica dos processos de conformação de chapa.

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OBJECTIVE: The aim of this pilot study was to describe problems in functioning and associated rehabilitation needs in persons with spinal cord injury after the 2010 earthquake in Haiti by applying a newly developed tool based on the International Classification of Functioning, Disability and Health (ICF). DESIGN: Pilot study. SUBJECTS: Eighteen persons with spinal cord injury (11 women, 7 men) participated in the needs assessment. Eleven patients had complete lesions (American Spinal Injury Association Impairment Scale; AIS A), one patient had tetraplegia. METHODS: Data collection included information from the International Spinal Cord Injury Core Data Set and a newly developed needs assessment tool based on ICF Core Sets. This tool assesses the level of functioning, the corresponding rehabilitation need, and required health professional. Data were summarized using descriptive statistics. RESULTS: In body functions and body structures, patients showed typical problems following spinal cord injury. Nearly all patients showed limitations and restrictions in their activities and participation related to mobility, self-care and aspects of social integration. Several environmental factors presented barriers to these limitations and restrictions. However, the availability of products and social support were identified as facilitators. Rehabilitation needs were identified in nearly all aspects of functioning. To address these needs, a multidisciplinary approach would be needed. CONCLUSION: This ICF-based needs assessment provided useful information for rehabilitation planning in the context of natural disaster. Future studies are required to test and, if necessary, adapt the assessment.

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A fundamental question in developmental biology is how tissues are patterned to give rise to differentiated body structures with distinct morphologies. The Drosophila wing disc offers an accessible model to understand epithelial spatial patterning. It has been studied extensively using genetic and molecular approaches. Bristle patterns on the thorax, which arise from the medial part of the wing disc, are a classical model of pattern formation, dependent on a pre-pattern of trans-activators and –repressors. Despite of decades of molecular studies, we still only know a subset of the factors that determine the pre-pattern. We are applying a novel and interdisciplinary approach to predict regulatory interactions in this system. It is based on the description of expression patterns by simple logical relations (addition, subtraction, intersection and union) between simple shapes (graphical primitives). Similarities and relations between primitives have been shown to be predictive of regulatory relationships between the corresponding regulatory factors in other Systems, such as the Drosophila egg. Furthermore, they provide the basis for dynamical models of the bristle-patterning network, which enable us to make even more detailed predictions on gene regulation and expression dynamics. We have obtained a data-set of wing disc expression patterns which we are now processing to obtain average expression patterns for each gene. Through triangulation of the images we can transform the expression patterns into vectors which can easily be analysed by Standard clustering methods. These analyses will allow us to identify primitives and regulatory interactions. We expect to identify new regulatory interactions and to understand the basic Dynamics of the regulatory network responsible for thorax patterning. These results will provide us with a better understanding of the rules governing gene regulatory networks in general, and provide the basis for future studies of the evolution of the thorax-patterning network in particular.

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Nykyään auton korien tuotekehitysprosessissa jää hyvin vähän aikaa korin rakenteiden optimointiin. Rakenteiden optimointi tehdään virtuaalitestauksen avulla siten, että yhdellä elementtimallilla tehdään erilaisia testejä ja optimoidaan useita omaisuuksia samanaikaisesti. Tässä tutkimuksessa tavoitteena on kehittää auton korin FEM-malli, jolla voidaan suorittaa mahdollisimman monta erilaista virtuaalitestiä. Rakennetun mallin toimivuutta testattiin tekemällä sille ympäriajoturvallisuustesti ja saatuja tuloksia verrattiin oikean auton testiin.