990 resultados para 187-1164


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Hoy en día la información sufre una evolución y transformación constantes, y para cualquier análisis o estudio hay que tener muy en cuenta las fuentes de información existentes en internet. El objetivo de este artículo es hacer un recorrido por la red centrando el interés en la selección de fuentes de información económica y empresarial. A la hora de seleccionar las fuentes electrónicas disponibles hay que tener en cuenta la diversa tipología documental existente: publicaciones periódicas, monografías, workingpapers, tesis, informes, actas de congresos, normas, patentes, etc.

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Volume 187 n. 1

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本书阐明了板壳断裂理论的基础。论证了Reissner型板壳断裂理论的科学性、经典板壳断裂理论的缺陷及在一定范围内仍具有的实用价值;介绍了作者所创意的研究Reissner型板壳断裂纹尖端场的方法等。

目录

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Adiabatic shear localization is a mode of failure that occurs in dynamic loading. It is characterized by thermal softening occurring over a very narrow region of a material and is usually a precursor to ductile fracture and catastrophic failure. This reference source is the first detailed study of the mechanics and modes of adiabatic shear localization in solids, and provides a systematic description of a number of aspects of adiabatic shear banding. The inclusion of the appendices which provide a quick reference section and a comprehensive collection of thermomechanical data allows rapid access and understanding of the subject and its phenomena. The concepts and techniques described in this work can usefully be applied to solve a multitude of problems encountered by those investigating fracture and damage in materials, impact dynamics, metal working and other areas. This reference book has come about in response to the pressing demand of mechanical and metallurgical engineers for a high quality summary of the knowledge gained over the last twenty years. While fulfilling this requirement, the book is also of great interest to academics and researchers into materials performance.

Table of Contents

1Introduction1
1.1What is an Adiabatic Shear Band?1
1.2The Importance of Adiabatic Shear Bands6
1.3Where Adiabatic Shear Bands Occur10
1.4Historical Aspects of Shear Bands11
1.5Adiabatic Shear Bands and Fracture Maps14
1.6Scope of the Book20
2Characteristic Aspects of Adiabatic Shear Bands24
2.1General Features24
2.2Deformed Bands27
2.3Transformed Bands28
2.4Variables Relevant to Adiabatic Shear Banding35
2.5Adiabatic Shear Bands in Non-Metals44
3Fracture and Damage Related to Adiabatic Shear Bands54
3.1Adiabatic Shear Band Induced Fracture54
3.2Microscopic Damage in Adiabatic Shear Bands57
3.3Metallurgical Implications69
3.4Effects of Stress State73
4Testing Methods76
4.1General Requirements and Remarks76
4.2Dynamic Torsion Tests80
4.3Dynamic Compression Tests91
4.4Contained Cylinder Tests95
4.5Transient Measurements98
5Constitutive Equations104
5.1Effect of Strain Rate on Stress-Strain Behaviour104
5.2Strain-Rate History Effects110
5.3Effect of Temperature on Stress-Strain Behaviour114
5.4Constitutive Equations for Non-Metals124
6Occurrence of Adiabatic Shear Bands125
6.1Empirical Criteria125
6.2One-Dimensional Equations and Linear Instability Analysis134
6.3Localization Analysis140
6.4Experimental Verification146
7Formation and Evolution of Shear Bands155
7.1Post-Instability Phenomena156
7.2Scaling and Approximations162
7.3Wave Trapping and Viscous Dissipation167
7.4The Intermediate Stage and the Formation of Adiabatic Shear Bands171
7.5Late Stage Behaviour and Post-Mortem Morphology179
7.6Adiabatic Shear Bands in Multi-Dimensional Stress States187
8Numerical Studies of Adiabatic Shear Bands194
8.1Objects, Problems and Techniques Involved in Numerical Simulations194
8.2One-Dimensional Simulation of Adiabatic Shear Banding199
8.3Simulation with Adaptive Finite Element Methods213
8.4Adiabatic Shear Bands in the Plane Strain Stress State218
9Selected Topics in Impact Dynamics229
9.1Planar Impact230
9.2Fragmentation237
9.3Penetration244
9.4Erosion255
9.5Ignition of Explosives261
9.6Explosive Welding268
10Selected Topics in Metalworking273
10.1Classification of Processes273
10.2Upsetting276
10.3Metalcutting286
10.4Blanking293
 Appendices297
AQuick Reference298
BSpecific Heat and Thermal Conductivity301
CThermal Softening and Related Temperature Dependence312
DMaterials Showing Adiabatic Shear Bands335
ESpecification of Selected Materials Showing Adiabatic Shear Bands341
FConversion Factors357
 References358
 Author Index369
 Subject Index375

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This dissertation is an assessment of the status of odontocetes in Hawaiian waters focussing on O´ahu. The work builds on available literature, and on data collected by the author and by others in Hawaiian waters. Abundance and distribution patterns of odontocetes were derived from stranding and aerial survey data. A stranding network operated by the National Marine Fisheries Service, Pacific Area Office collected 187 stranding reports throughout the main Hawaiian Islands between 1937 and 2002. These reports included 16 odontocete species. Number of stranding reports increased over time and was highest on O´ahu. Strandings occurred throughout the year. The difference in number of strandings per month was not significant. Fifteen of the 16 species reported in the stranding record for the main Hawaiian Islands were also reported by aerial survey studies of the area between 1993 and 1998. Only 7 of the species reported were detected during aerial transects around O′ahu between 1998 and 2000. Based on the stranding record, Kogia sp., melon-headed whales, striped dolphins and dwarf killer whale appear to be more common than suggested by aerial surveys. Conversely, pilot whales and bottlenose dolphins were more common, according to aerial surveys, than predicted by the stranding data. Aerial surveys of waters between 0 and 500m around the Island of O′ahu showed that the most abundant species by frequency of occurrence was the pilot whale (30% of sightings), followed by the spinner (16%) and bottlenose dolphin (14%). Because of small sample size, abundance estimates for odontocetes have a high level of uncertainty. The unavailability of a correction factor for g(0)<1, and the reduced visibility below the aircraft further reduced accuracy and increased the inherent underestimation in the data. The most abundant species according to distance sampling estimates were spotted dolphins, pilot whales, false killer whales and spinner dolphins. A natural factor shaping the ecology of odontocete populations is predation pressure both by other odontocetes and, more frequently, by sharks. An account of predation by a tiger shark on a spotted dolphin near Penguin Banks is used as an example of the potential mechanisms of predation by sharks on odontocetes.

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[EN] This article investigates the question of the licensing of null arguments in the so-called pro-drop languages. By focusing on the licensing of null subjects in the different types of -T(Z)E nominalizations in Basque, it aims at defining in a precise way the crucial feature that makes pro-drop possible in a clause. The central claim is that what licenses subject-drop is the assignment of structural Case. That is, it is argued that a subject can be null if and only if it is assigned structural Case. Different aspects of T(Z)E nominalizations are also explored, which show that even if these clauses are similar in the surface, they can be syntactically very different and furthermore, that infinitive clauses marked with the same nominalizing morpheme can also have diverging structures.

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Uno de los objetivos de este artículo ha sido identificar el modo en que las nuevas formas organizativas suponen una transformación drástica con respecto a los modelos tradicionales. Los nuevos modelos y, en particular, el de organización virtual supone la aparición de un nuevo marco conceptual. La innovación no reside tanto en que se abordan nuevas soluciones para los problemas, como en la transformación de los propios problemas y cuestiones clave.

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El objetivo de este artículo es diseñar una estrategia de búsqueda que nos ayude a localizar información sobre un tema concreto: Ética, economía y empresa. El punto de partida será una estrategia de búsqueda determinada que servirá como excusa para consultar una selección de diversas fuentes de información: catálogo de la biblioteca, bases de datos y revistas electrónicas. Para finalizar el articulo se propone como instrumento para seleccionar resultados el factor de impacto JCR y como medio mara gestionar las referencias bibliográficas el gestor Reference Manager

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Começou a ser distribuído hoje o parecer do relator Bernardo Cabral às duas mil emendas apresentadas ao projeto de Constituição. O relator deu parecer a favor de 30% das emendas, rejeitando a maioria. As emendas com 280 assinaturas nem sempre receberam parecer favorável, mas foram todas acolhidas. De acordo com o novo Regimento, o parecer do Relator tem importância secundária, porque todos os artigos terão que ser votados no Plenário. Caso a emenda não tenha sido aprovada pelo relator, o constituinte pode apresentar um destaque para que o assunto volte a análise de todos os constituintes. Constituintes fazem um gráfico em que evidencia os assuntos consensuais. A partir de amanhã começa a faze do pedido de destaque. Os constituintes terão até a segunda feira, às 6 da tarde para apresentar os seus pedidos. Cada constituinte tem direito a 6 destaques. O destaque para votação em separado precisa de 187 assinaturas. As matérias da Ordem econômica e da Ordem social, receberá atenção especial. Constituintes encontram dificuldades diante das restrições do Regimento.

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Analisa o debate em torno da atividade dos grupos de pressão, especialmente a sua regulamentação, prática essa também conhecida como lobby. Para isso, dividiu-se a análise em quatro partes, incluindo conceitos, teorias consagradas, formas e mecanismos de atuação e as possibilidades de regulamentação da atividade no Brasil.

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The aim of this study was to examine areas in which fishermen cooperatives can become involved and then suggest operational guidelines in order to increase fishermen income and also to make the Green Revolution Programme a success through increased production of fish. The paper enumerated different areas in which fishermen cooperatives can participate. These include: thrift and credits, thrift and savings, consumers and building cooperative societies. It is the belief of the author that the expansion of fishermen cooperatives into the areas mentioned in this paper can enable members to process and market their products more economically, buy supplies and equipment in large quantities and obtain lower cost credit