463 resultados para initialisation flaws


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The MID-K, a new kind of multi-pipe string detection tool is introduced. This tool provides a means of evaluating the condition of in-place pipe string, such as tubing and casino. It is capable of discriminating the defects of the inside and outside, and estimating the thickness of tubing and casing. It is accomplished by means of a low frequency eddy current to detect flaws on the inner surface and a magnetic flux leakage to inspect the full thickness. The measurement principle, the technology and applications are presented in this paper.

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This report compares the legal status of research data in the four KE partner countries. The report also addresses where European copyright and database law poses flaws and obstacles to the access to research data and singles out pre-conditions for openly available data. Background of the study Intellectual property right regulations regarding primary research data are a recurrent topic in the discussion on the improvement of access to research data. In fact in the final report of the High Level Expert Group on Scientific Data ‘Riding the Wave’ creating clarity on this was considered very important in improving awareness for all parties involved. According to the recommendations of the report legal issues should be “worked out so that they encourage, and not impede, global data sharing” http://cordis.europa.eu/fp7/ict/e-infrastructure/docs/hlg-sdi-report.pdf. While open access to research data is a widely recognised goal, achieving it remains a challenge. As European national laws still diverge and sometimes remain unclear it can be difficult for interested parties to fully comprehend in which ways open access to research data can be legally obtained. Based on these discussions the Knowledge Exchange working group on primary research data has commissioned a comparative report on the legal status of research data in the four KE partner countries. The study has been conducted by the Centre for Intellectual Property Law (CIER) at Utrecht University. The report aims at informing Knowledge Exchange and associated stakeholders on the state of the law concerning access to research data in the KE partner countries (Germany, Denmark, the Netherlands, and the United Kingdom) and to give an insight in how these laws work in practice. This is explained in several characteristic situations pertaining to open access to research data. The purpose of the report is to identify flaws and obstacles to the access to research data and to single out pre-conditions for openly available data. This is in view of the current discussions concerning open access to research data, especially those originating from publicly funded research. The report intends to be both a description of the status quo of the legislation and a practical instrument to prepare further activities in raising awareness on the potential benefit of improved access to research data, and developing means to support the improved access for research purposes

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Amorphous metals that form fully glassy parts over a few millimeters in thickness are still relatively new materials. Their glassy structure gives them particularly high strengths, high yield strains, high hardness values, high resilience, and low damping losses, but this can also result in an extremely low tolerance to the presence of flaws in the material. Since this glassy structure lacks the ordered crystal structure, it also lacks the crystalline defect (dislocations) that provides the micromechanism of toughening and flaw insensitivity in conventional metals. Without a sufficient and reliable toughness that results in a large tolerance of damage in the material, metallic glasses will struggle to be adopted commercially. Here, we identify the origin of toughness in metallic glass as the competition between the intrinsic toughening mechanism of shear banding ahead of a crack and crack propagation by the cavitation of the liquid inside the shear bands. We present a detailed study over the first three chapters mainly focusing on the process of shear banding; its crucial role in giving rise to one of the most damage-tolerant materials known, its extreme sensitivity to the configurational state of a glass with moderate toughness, and how the configurational state can be changed with the addition of minor elements. The last chapter is a novel investigation into the cavitation barrier in glass-forming liquids, the competing process to shear banding. The combination of our results represents an increased understanding of the major influences on the fracture toughness of metallic glasses and thus provides a path for the improvement and development of tougher metallic glasses.

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An understanding of the mechanics of nanoscale metals and semiconductors is necessary for the safe and prolonged operation of nanostructured devices from transistors to nanowire- based solar cells to miniaturized electrodes. This is a fascinating but challenging pursuit because mechanical properties that are size-invariant in conventional materials, such as strength, ductility and fracture behavior, can depend critically on sample size when materials are reduced to sub- micron dimensions. In this thesis, the effect of nanoscale sample size, microstructure and structural geometry on mechanical strength, deformation and fracture are explored for several classes of solid materials. Nanocrystalline platinum nano-cylinders with diameters of 60 nm to 1 μm and 12 nm sized grains are fabricated and tested in compression. We find that nano-sized metals containing few grains weaken as sample diameter is reduced relative to grain size due to a change from deformation governed by internal grains to surface grain governed deformation. Fracture at the nanoscale is explored by performing in-situ SEM tension tests on nanocrystalline platinum and amorphous, metallic glass nano-cylinders containing purposely introduced structural flaws. It is found that failure location, mechanism and strength are determined by the stress concentration with the highest local stress whether this is at the structural flaw or a microstructural feature. Principles of nano-mechanics are used to design and test mechanically robust hierarchical nanostructures with structural and electrochemical applications. 2-photon lithography and electroplating are used to fabricate 3D solid Cu octet meso-lattices with micron- scale features that exhibit strength higher than that of bulk Cu. An in-situ SEM lithiation stage is developed and used to simultaneously examine morphological and electrochemical changes in Si-coated Cu meso-lattices that are of interest as high energy capacity electrodes for Li-ion batteries.

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Talbot effect of a grating with different flaws is analyzed with the finite-difference time-domain (FDTD) method. The FDTD method can show the exact near-field distribution of different flaws in a high-density grating, which is impossible to obtain with the conventional Fourier transform method. The numerical results indicate that if a grating is perfect, its Talbot imaging should also be perfect; if the grating is distorted, its Talbot imaging would also be distorted. Furthermore, we can evaluate high density gratings by detecting the near-field distribution.

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The article analyses the construction process, the evolution and the disturbing future of the facade enclosure of the collective housing constructions built during the developmental period in the province of Gipuzkoa. 128 residential complexes were checked, and 17 people who directly took part in the construction of many of these buildings were interviewed. After examining the material and elements that make up the conventional facade solution used in Gipuzkoa and in much of Spain not only during those years but also up to the present time, the effects and causes of its main damages and flaws were studied. Its complex and costly adaptation to current demands is going to require a strong effort from society at large, and this raises the question of whether the life cycle of this construction system should be terminated once and for all.

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O presente trabalho, plasmado em metodologia jurídica, reflete criticamente sobre o problema da motivação da sentença civil como elemento de organização e de funcionamento do Estado Constitucional Democrático de Direito. A motivação é condição essencial de jurisdicionalidade, no sentido de que sem motivação não há exercício legítimo da função jurisdicional. O trabalho faz uma abordagem da natureza da motivação como discurso justificativo, jurídico e racional, da validade dos critérios de escolha ou de valoração empregados pelo juiz em sua decisão. O raciocínio do juiz é apresentado sob dupla feição: raciocínio decisório interno (contexto de descoberta ou deliberação) e raciocínio justificativo externo (contexto de justificação ou de validação). O conjunto das funções técnico-instrumental (endoprocessual) e político-garantística (extraprocessual) é objeto de investigação. A motivação, nos planos teórico e prático, exerce também a função de garantia do garantismo processual. A tese da inexistência jurídica da sentença tem três eixos teóricos: omissão total da motivação gráfica; falta de motivação ideológica, equiparada à hipótese de ausência de motivação gráfica; incompatibilidade lógica radical entre as premissas ou entre as premissas e a conclusão final, que também equivale à ausência total de motivação. O trabalho retrata um modelo de injustiça atemporal vivificado pelo juiz Crono, oposto à motivação como inestimável fator de legitimação argumentativa da jurisdição. A obrigatoriedade de motivação pública é o traço característico da jurisdição de nossa contemporaneidade e representa a maior conquista civilizatória do processo équo e justo.

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This paper presents nine tenets for management as formulated in the literature in recent decades. These tenets, and the principles behind them, form the foundation for systemic management. All tenets are interrelated and far from mutually exclusive or discrete. When we consider them seriously and simultaneously, these tenets expose serious flaws of conventional resource management and define systemic management. Systemic management requires that we manage inclusively and avoid restricting management to any particular interaction between humans and other elements of nature. The management tenets presented here are considered with particular attention to the interrelationships among both the tenets and principles upon which they are based. The case is made that the tenets are inseparable and should be applied collectively. Combined consideration of the tenets clarifies the role of science, contributes to progress in defining management, and leads to the development of ways we can avoid mistakes of past management. Systemic management emerges as at least one form of management that will consistently account for and apply to the complexities of nature.

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Hoje em dia, distribuições de grandes volumes de dados por redes TCP/IP corporativas trazem problemas como a alta utilização da rede e de servidores, longos períodos para conclusão e maior sensibilidade a falhas na infraestrutura de rede. Estes problemas podem ser reduzidos com utilização de redes par-a-par (P2P). O objetivo desta dissertação é analisar o desempenho do protocolo BitTorrent padrão em redes corporativas e também realizar a análise após uma modificação no comportamento padrão do protocolo BitTorrent. Nesta modificação, o rastreador identifica o endereço IP do par que está solicitando a lista de endereços IP do enxame e envia somente aqueles pertencentes à mesma rede local e ao semeador original, com o objetivo de reduzir o tráfego em redes de longa distância. Em cenários corporativos típicos, as simulações mostraram que a alteração é capaz de reduzir o consumo médio de banda e o tempo médio dos downloads, quando comparados ao BitTorrent padrão, além de conferir maior robustez à distribuição em casos de falhas em enlaces de longa distância. As simulações mostraram também que em ambientes mais complexos, com muitos clientes, e onde a restrição de banda em enlaces de longa distância provoca congestionamento e descartes, o desempenho do protocolo BitTorrent padrão pode ser semelhante a uma distribuição em arquitetura cliente-servidor. Neste último caso, a modificação proposta mostrou resultados consistentes de melhoria do desempenho da distribuição.

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A indústria de petróleo e gás apresenta sérios problemas relacionados à corrosão. Nas petroquímicas e nas instalações de refino de petróleo, as falhas em materiais estão relacionadas com a corrosão, além disso, os processos de corrosão de metais são problemas no mundo, causando ônus em processos industriais e gerando situações de risco como a corrosão de pilares metálicos em pontes ou em fuselagens de aviões. Dentre os meios corrosivos, um muito comum é o meio ácido, que será o meio estudado neste trabalho. Com todos os problemas citados, se faz necessário o estudo de inibidores de corrosão com alta eficiência, estabilidade e que, preferencialmente, não agridam o meio ambiente. Alguns inibidores de corrosão apresentam solubilidade limitada em água, sendo necessária a utilização de alguns solventes não tão amigáveis ao meio ambiente. Então, propôs-se formar um complexo de inclusão para tornar possível a solubilização de inibidores convencionais em solução aquosa, como algumas tioureias, que apresentam solubilidade limitada em água. Essa completa solubilização do inibidor de corrosão orgânico em meio aquoso é possível com a utilização de um aditivo (hospedeiro) capaz de encapsular tais moléculas (convidados) via interações não covalentes, de modo a alcançar o máximo desempenho de inibição. Para a formação do complexo de inclusão foi usado como molécula hospedeira, a α e a β hidroxipropilciclodextrina e como molécula convidada a dibenziltioureia. A intenção foi testar a melhora da ação inibidora da corrosão do aço carbono em meio de HCl 1mol.L-1 com ensaios de perda de massa, de impedância, polarização e microscopia eletrônica de varredura (MEV), além de evidenciar a formação destes complexos de inclusão através da espectroscopia de absorção vibracional no infravermelho, espectroscopia de RMN de 1H, espectroscopia de absorção no Ultra-violeta e análise térmica diferencial (DTA)

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The use of PC-based PD6493:1991 fracture assessment procedures has revealed that, under certain circumstances, flaws of different dimensions may be found as being limiting or critical for identical applied conditions. The main causes for multiple solutions are a steep applied stress gradient, residual stress relaxation and flaw re-characterisation. This work uses several case studies to illustrate some of the circumstances under which multiple solutions occurs.

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Accurate simulation of rolling-tyre vibrations, and the associated noise, requires knowledge of road-surface topology. Full scans of the surface types in common use are, however, not widely available, and are likely to remain so. Ways of producing simulated surfaces from incomplete starting information are thus needed. In this paper, a simulation methodology based solely on line measurements is developed, and validated against a full two-dimensional height map of a real asphalt surface. First the tribological characteristics-asperity height, curvature and nearest-neighbour distributions-of the real surface are analysed. It is then shown that a standard simulation technique, which matches the (isotropic) spectrum and the probability distribution of the height measurements, is unable to reproduce these characteristics satisfactorily. A modification, whereby the inherent granularity of the surface is enforced at the initialisation stage, is introduced, and found to produce simulations whose tribological characteristics are in excellent agreement with the measurements. This method will thus make high-fidelity tyre-vibration calculations feasible for researchers with access to line-scan data only. In addition, the approach to surface tribological characterisation set out here provides a template for efficient cataloguing of road textures, as long as the resulting information can subsequently be used to produce sample realisations. A third simulation algorithm, which successfully addresses this requirement, is therefore also presented. © 2011 Elsevier B.V.

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The absence of adequate inspection data from difficult-to-access areas on pipelines, such as cased-road crossings, makes determination of fitness for continued service and compliance with increasingly stringent regulatory requirements problematic. Screening for corrosion using long-range guided wave testing is a relatively new inspection technique. The complexity of the possible modes of vibration means the technique can be difficult to implement effectively but this also means that it has great potential for both detecting and characterizing flaws. The ability to determine flaw size would enable the direct application of standard procedures for determining fitness-for-service, such as ASME B31G, RSTRENG, or equivalent for tens of metres of pipeline from a single inspection location. This paper presents a new technique for flaw sizing using guided wave inspection data. The technique has been developed using finite element models and experimentally validated on 6'' Schedule 40 steel pipe. Some basic fitness-for-service assessments have been carried out using the measured values and the maximum allowable operating pressure was accurately determined. © 2011 American Institute of Physics.

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This paper reports the mechanical properties and fracture behavior of silicon carbide (3C-SiC) thin films grown on silicon substrates. Using bulge testing combined with a refined load-deflection model of long rectangular membranes, which takes into account the bending stiffness and prestress of the membrane material, the Young's modulus, prestress, and fracture strength for the 3C-SiC thin films with thicknesses of 0.40 and 1.42 mu m were extracted. The stress distribution in the membranes under a load was calculated analytically. The prestresses for the two films were 322 +/- 47 and 201 +/- 34 MPa, respectively. The thinner 3C-SiC film with a strong (111) orientation has a plane-gstrain moduli of 415 +/- 61 GPa, whereas the thicker film with a mixture of both (111) and (110) orientations exhibited a plane-strain moduli of 329 +/- 49 GPa. The corresponding fracture strengths for the two kinds of SiC films were 6.49 +/- 0.88 and 3.16 +/- 0.38 GPa, respectively. The reference stresses were computed by integrating the local stress of the membrane at the fracture over edge, surface, and volume of the specimens and were fitted with Weibull distribution function. For the 0.40-mu m-thick membranes, the surface integration has a better agreement between the data and the model, implying that the surface flaws are the dominant fracture origin. For the 1.42-mu m-thick membranes, the surface integration presented only a slightly better fitting quality than the other two, and therefore, it is difficult to rule out unambiguously the effects of the volume and edge flaws.

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The mechanical properties and fracture behavior of silicon nitride (SiNx) thin film fabricated by plasma-enhanced chemical vapor deposition is reported. Plane-strain moduli, prestresses, and fracture strengths of silicon nitride thin film; deposited both oil a bare Si substrate and oil a thermally oxidized Si substrate were extracted using bulge testing combined with a refined load-deflection model of long rectangular membranes. The plane-strain modu i and prestresses of SiNx thin films have little dependence on the substrates, that is, for the bare Si substrate, they are 133 +/- 19 GPa and 178 +/- 22 MPa, respectively, while for the thermally oxidized substrate, they are 140 +/- 26 Gila and 194 +/- 34 MPa, respectively. However, the fracture strength values of SiNx films grown on the two substrates are quite different, i.e., 1.53 +/- 0.33 Gila and 3.08 +/- 0.79 GPa for the bare Si substrate a A the oxidized Si substrate, respectively. The reference stresses were computed by integrating the local stress of the membrane at the fracture over the edge, Surface, and volume of the specimens and fitted with the Weibull distribution function. For SiNx thin film produced oil the bare Si Substrate, the Volume integration gave a significantly better agreement between data and model, implying that the volume flaws re the dominant fracture origin. For SiNx thin film grown on the oxidized Si substrate, the fit quality of surface and edge integration was significantly better than the Volume integration, and the dominant surface and edge flaws could be caused by buffered HF attacking the SiNx layer during SiO2 removal. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.