213 research outputs found
The WTO: A Train Wreck in Progress?
This article argues that the WTO entrenches an asymmetrical, non-reciprocal trading system that benefits multi-national corporations especially, at the expense of industrial workers, farmers, and a wide range of business enterprises. It argues that the WTO doesn\u27t deserve to survive in its present, unbalanced, and unsustainable form, and that it is doubtful that its voting regime, accumulated asymmetries, and overall rigidity can be overhauled. The author posits that bilateral and regional trade bargaining will become increasingly important and that world market forces are likely to bypass, and perhaps overwhelm, the WTO
Fabric anisotropy & DEM informed two-surface hyperplasticity : constitutive formulation, asymptotic states & experimental validation.
In geotechnical analysis continuum idealisations of the bulk material still provide the most appropriate approach for engineers designing large-scale structures. In this area, the most successful framework for describing the behaviour of soils is Critical State (CS) soil mechanics. However, the findings from discrete element method (DEM) analysis, such as the uniqueness of the CS, can provide invaluable information in the
development such models. This paper details the key concepts behind a two-surface hyperplasticity model (?) whose development was informed by recent DEM findings on the uniqueness of the CS. Asymptotic states of the model will be confirmed and the DEM-continuum-experimental loop will be closed through comparison of the developed model with experimental data on coarse-grained particulate media. This will demonstrate, that providing the previous stress history is accounted for, the proposed model is suitable for a variety of particulate media
Impact of a Pharmacy Benefit Change on New Use of Mail Order Pharmacy among Diabetes Patients: The Diabetes Study of Northern California (DISTANCE)
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110855/1/hesr12223-sup-0001-AuthorMatrix.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/110855/2/hesr12223.pd
Quasibrittle fracture scaling and size effect
The report attempts a broad review of the problem of size effect or scaling of failure, which has recently come to the forefront of attention because of its importance for concrete and geotechnical engineering, geomechanics, arctic ice engineering, as well as in designing large loadbearing parts made of advanced ceramics and composites, e.g. for aircraft or ships. First the main results of Weibull statistical theory of random strength are briefly summarized and its applicability and limitations described. In this theory as well as plasticity, elasticity with a strength limit, and linear elastic fracture mechanics (LEFM), the size effect is a simple power law because no characteristic size or length is present. Attention is then focused on the deterministic size effect in quasibrittle materials which, because of the existence of a non-negligible material length characterizing the size of the fracture process zone, represents the bridging between the simple powerlaw size effects of plasticity and of LEFM. The energetic theory of quasibrittle size effect in the bridging region is explained and then a host of recent refinements, extensions and ramifications are discussed. Comments on other types of size effect, including that which might be associated with the fractal geometry of fracture, are also made. The historical development of the size effect theories is outlined and the recent trends of research are emphasized
Quasibrittle fracture scaling and size effect
The report attempts a broad review of the problem of
size effect or scaling of failure, which has recently come
to the forefront of attention because of its importance
for concrete and geotechnical engineering, geomechanics,
arctic ice engineering, as well as in designing large loadbearing
parts made of advanced ceramics and composites,
e.g. for aircraft or ships. First the main results of Weibull
statistical theory of random strength are briefly summarized
and its applicability and limitations described. In
this theory as well as plasticity, elasticity with a strength
limit, and linear elastic fracture mechanics (LEFM), the
size effect is a simple power law because no characteristic
size or length is present. Attention is then focused
on the deterministic size effect in quasibrittle materials
which, because of the existence of a non-negligible material
length characterizing the size of the fracture process
zone, represents the bridging between the simple powerlaw
size effects of plasticity and of LEFM. The energetic
theory of quasibrittle size effect in the bridging region is
explained and then a host of recent refinements, extensions
and ramifications are discussed. Comments on other
types of size effect, including that which might be associated
with the fractal geometry of fracture, are also made.
The historical development of the size effect theories is
outlined and the recent trends of research are emphasized
Diagnosis / Intervention criteria in damaged slabs by severe corrosion of prestressed joists
This research defines diagnosis criteria in R/C one-way slabs with severe corrosion at the lower prestressed reinforcement of the joists and proposes specific actuation criteria and constructive recommendations to increase the safety. The corrosion of this reinforcement is the most common damage in building structures, and the use of aluminous cement in the precast joists can aggravate the corrosion.
The usual cases of entire residential buildings with different degrees of damage and with a few or all joists affected in a slab have been simulated. ACI-318 is used as an acceptance criterion for existing structures in the simulations, and a ratio between the ultimate load and the service load is defined as valuation coefficient. By this way, the residual safety for a damaged structure is known.
Results are in accordance with the extensive experience in real intervention cases, which often still have high safety reserves.Vercher Sanchis, JM.; Gil Benso, E.; Mas Tomas, MDLA.; Lerma Elvira, C. (2013). Diagnosis / Intervention criteria in damaged slabs by severe corrosion of prestressed joists. Journal of Performance of Constructed Facilities. (04014040). doi:10.1061/(ASCE)CF.1943-5509.0000515S0401404
Residual safety for flexural bending of slabs with corrosion in the joists
[EN] A large number of slabs with severe corrosion problems at the precast joists have appeared in Spain, often increased by the use of aluminous cement. The purpose of this paper is to evaluate the residual safety for the bending mechanisms in the most common cases of damaged slabs, to decide the magnitude of the needed intervention. The damaged slabs have been evaluated as a part of an entire building, since the boundary conditions are essential for obtaining actual behavior, taking into account the different phases of the construction process and deterioration over time. A major cracking in the
constructive elements are not frequently observed in inspections, and it is found that there is a sufficient residual safety to undertake the rehabilitation works without exceptional measures.[ES] A nivel nacional han aparecido un gran número de forjados de viguetas prefabricadas con graves problemas de corrosión, potenciada en muchas ocasiones por el empleo del cemento aluminoso. El propósito de este trabajo es evaluar la seguridad residual de los mecanismos de flexión en los casos más habituales de forjados dañados, para decidir la magnitud de la intervención necesaria.
Los forjados dañados se han evaluado formando parte de un edificio completo, ya que las condiciones de contorno son fundamentales para la obtención del Comportamiento real, teniendo en cuenta las distintas fases del proceso constructivo y de deterioro en el tiempo. En bastantes ocasiones en la inspección no se observa una fisuración importante en los elementos constructivos, como solados o tabiquerÃa, y hemos comprobado que existe una seguridad residual suficiente para acometer las obras de rehabilitación sin necesidad de adoptar medidas excepcionales.Gil Benso, E.; Vercher Sanchis, JM.; Mas Tomas, MDLA.; Fenollosa Forner, EJ. (2015). Seguridad remanente a flexión en forjados con corrosión en las viguetas. Informes de la Construcción. 67(537):1-10. doi:10.3989/ic.13.084S11067537Morán Cabré, F. (1994). Estimación de la seguridad residual en estructuras de hormigón con problemas patológicos. Informes de la Construcción, 46(434), 39-51. doi:10.3989/ic.1994.v46.i434.1107(2) Giménez, E. (2007). Estudio experimental y numérico de soportes de hormigón armado reforzados con perfiles metálicos sometidos a esfuerzos de compresión simple (Tesis Doctoral). Valencia: Universidad Politécnica de Valencia.(3) Vieitez, J.A., RamÃrez, J.L. (1984). PatologÃa de la Construcción en Espa-a: Aproximación EstadÃstica. Resumen de Tesis Doctoral. Informes de la Construcción, 36(364): 5-15.(4) Instituto Valenciano de la Edificación (IVE). (2008). GuÃa para la Inspección y Evaluación Preliminar de estructuras de hormigón en edificios existentes. Serie guÃas de la calidad. Valencia: Generalitat Valenciana - Conselleria de Medi Ambient, Aigua, Urbanisme i Habitatge.(5) Instituto Valenciano de la Edificación (IVE). (2008). Experiencia en Inspección de estructuras en edificios. Comunidad Valenciana 1991-2008. Serie guÃas de la calidad. Valencia: Generalitat Valenciana - Conselleria de Medi Ambient, Aigua, Urbanisme i Habitatge.(6) Grupo Espa-ol del Hormigón (GEHO). (1994). Reparación y refuerzo de estructuras hormigón. GuÃa FIP de buena práctica. BoletÃn GEHO, 14. Madrid.Evangelista, A. D., Leonardis, A. D., Valente, C., & Zuccarino, L. (2011). Design and testing of corrosion damaged prestressed concrete joists: the Pescara Benchmark. Journal of Physics: Conference Series, 305, 012081. doi:10.1088/1742-6596/305/1/012081Coronelli, D., & Gambarova, P. (2004). Structural Assessment of Corroded Reinforced Concrete Beams: Modeling Guidelines. Journal of Structural Engineering, 130(8), 1214-1224. doi:10.1061/(asce)0733-9445(2004)130:8(1214)Foster, S. ., Bailey, C. ., Burgess, I. ., & Plank, R. . (2004). Experimental behaviour of concrete floor slabs at large displacements. Engineering Structures, 26(9), 1231-1247. doi:10.1016/j.engstruct.2004.04.002(11) Ministerio de Vivienda. (2006, 28 de marzo). Código Técnico de la Edificación (CTE). BoletÃn Oficial del Estado, nº 74: 11816-11831. Madrid, Espa-a.(12) Bangash, M.Y.H. (1989). Concrete and concrete structures: Numerical modeling and applications. London - New York: Elsevier Applied Science.(13) Willam, K.J., Warnke, E.D. (1975). Constitutive model for the triaxial behavior of concrete. En Proceedings of the International Association for Bridge and Structural Engineering, ISMES, 19: 1-30. Bergamo, Italy.(14) Vercher, J. (2013). Seguridad residual en los forjados con corrosión severa (Tesis Doctoral). Valencia: Universidat Politècnica de València.Cubel, F., Mas, A., Vercher, J., & Gil, E. (2012). Design and construction recommendations for brick enclosures with continuous air chamber. Construction and Building Materials, 36, 151-164. doi:10.1016/j.conbuildmat.2012.04.128Brencich, A., & Felice, G. de. (2009). Brickwork under eccentric compression: Experimental results and macroscopic models. Construction and Building Materials, 23(5), 1935-1946. doi:10.1016/j.conbuildmat.2008.09.004Dilrukshi, K. G. S., Dias, W. P. S., & Rajapakse, R. K. N. D. (2010). Numerical modelling of cracks in masonry walls due to thermal movements in an overlying slab. Engineering Structures, 32(5), 1411-1422. doi:10.1016/j.engstruct.2010.01.019(18) Fanning, P. (2001). Nonlinear models of reinforced and post-tensioned concrete beams. Electronic Journal of Structural Engineering, 2: 111-119.(19) Tavio, T., Tata, A. (2009). Predicting nonlinear behavior and stress-strain relationship of rectangular confined reinforced concrete columns with Ansys. Civil Engineering Dimension, 11(1): 23-31.Rodriguez, J., Ortega, L., & Casal, J. (1997). Load carrying capacity of concrete structures with corroded reinforcement. Construction and Building Materials, 11(4), 239-248. doi:10.1016/s0950-0618(97)00043-
Application of plastic-damage multidirectional fixed smeared crack model in analysis of RC structures
This paper describes a plasticity-damage multidirectional fixed smeared cracking (PDSC) model to simulate the failure process of concrete and reinforced concrete (RC) structures subjected to different loading paths. The model proposes a unified approach combining a multidirectional fixed smeared crack model to simulate the crack initiation and propagation with a plastic-damage model to account for the inelastic compressive behaviour of concrete between cracks. The smeared crack model considers the possibility of forming several cracks in the same integration point during the cracking process. The plasticity part accounts for the development of irreversible strains and volumetric strain in compression, whereas the strain softening and stiffness degradation of the material under compression are controlled by an isotropic strain base damage model. The theoretical aspects about coupling the fracture, plasticity, and damage components of the model, as well as the model appraisal at both material and structural levels, have been detailed in a former publication. This study briefly summarizes the model formulations, and is mainly dedicated to further explore the potentialities of the proposed constitutive model for the analysis of concrete and RC structures. The model is employed to simulate experimental tests that are governed by nonlinear phenomenon due to simultaneous occurrence of cracking and inelastic deformation in compression. The numerical simulations have predicted with good accuracy the load carrying capacity, ductility, crack pattern, plastic (compressive) zone, and failure modes of all types of structures analysed. The influence of the model parameters that simulate the nonlinear behaviour of concrete under tension and compression is analysed through a parametric study.Portuguese Foundation for Science and Technology in the scope of the SlabSys-HFRC research project, with reference PTDC/ECM/120394/201
14th Annual Conference on Legal Issues For Financial Institutions
Materials from the 14th Annual Conference on Legal Issues For Financial Institutions held by UK/CLE in March 1994
Increased oxidative metabolism following hypoxia in the type 2 diabetic heart, despite normal hypoxia signalling and metabolic adaptation
Hypoxia activates the hypoxia-inducible factor (HIF), promoting glycolysis and suppressing mitochondrial respiration. In the type 2 diabetic heart, glycolysis is suppressed whereas fatty acid metabolism is promoted. The diabetic heart experiences chronic hypoxia as a consequence of increased obstructive sleep apnoea and cardiovascular disease. Given the opposing metabolic effects of hypoxia and diabetes, we questioned whether diabetes affects cardiac metabolic adaptation to hypoxia. Control and type 2 diabetic rats were housed for 3 weeks in normoxia or 11% oxygen. Metabolism and function were measured in the isolated perfused heart using radiolabelled substrates. Following chronic hypoxia, both control and diabetic hearts upregulated glycolysis, lactate efflux and glycogen content and decreased fatty acid oxidation rates, with similar activation of HIF signalling pathways. However, hypoxia-induced changes were superimposed on diabetic hearts that were metabolically abnormal in normoxia, resulting in glycolytic rates 30% lower, and fatty acid oxidation 36% higher, in hypoxic diabetic hearts than hypoxic controls. Peroxisome proliferator-activated receptor α target proteins were suppressed by hypoxia, but activated by diabetes. Mitochondrial respiration in diabetic hearts was divergently activated following hypoxia compared with controls. These differences in metabolism were associated with decreased contractile recovery of the hypoxic diabetic heart following an acute hypoxic insult. In conclusion, type 2 diabetic hearts retain metabolic flexibility to adapt to hypoxia, with normal HIF signalling pathways. However, they are more dependent on oxidative metabolism following hypoxia due to abnormal normoxic metabolism, which was associated with a functional deficit in response to stress
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