921 resultados para [JEL:D02] Microeconomics - General - Institutions: Design, Formation, and Operations
Resumo:
The construction industry with its nature of project delivery is very fragmented in terms of the various processes that encompass design, construction, facilities and assets management. Facilities managers are in the forefront of delivering sustainable assets management and hence further the venture for mitigation and adaptation to climate change. A questionnaire survey was conducted to establish perceptions, level of commitment and knowledge chasm in practising sustainable facilities management (FM). This has significant implications for sustainable design management, especially in a fragmented industry. The majority of questionnaire respondents indicated the importance of sustainability for their organization. Many of them stated that they reported on sustainability as part of their organization annual reporting with energy efficiency, recycling and waste reduction as the main concern for them. The overwhelming barrier for implementing sound, sustainable FM is the lack of consensual understanding and focus of individuals and organizations about sustainability. There is a knowledge chasm regarding practical information on delivering sustainable FM. Sustainability information asymmetry in design, construction and FM processes render any sustainable design as a sentiment and mere design aspiration. Skills and training provision, traditionally offered separately to designers and facilities managers, needs to be re-evaluated. Sustainability education and training should be developed to provide effective structures and processes to apply sustainability throughout the construction and FM industries coherently and as common practice.
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This paper summarizes the design, manufacturing, testing, and finite element analysis (FEA) of glass-fibre-reinforced polyester leaf springs for rail freight vehicles. FEA predictions of load-deflection curves under static loading are presented, together with comparisons with test results. Bending stress distribution at typical load conditions is plotted for the springs. The springs have been mounted on a real wagon and drop tests at tare and full load have been carried out on a purpose-built shaker rig. The transient response of the springs from tests and FEA is presented and discussed.
Resumo:
With the increasing production and consumption of potato and its products, glycoalkaloid (GA) formation and toxicity are likely to become an important focus for food safety researchers and public health agencies. Not only the presence of GA, particularly in the form of a-solanine and a-chaconine, but also the changes occurring as a result of various post-harvest handling practices and storage, are critical issues influencing the quality of stored potatoes. Studies on various factors (pre-harvest, during harvest anal post-harvest) affecting GA have been carried out from time to time, but it is difficult to compare the results of one study with another due to wide variation in the parameters chosen. This review aims to develop a clear understanding of these issues. Published information on the types of GA, their effects on health, their typical concentrations in potatoes, their formation mechanisms, and how their levels can be controlled by following appropriate post harvest practices and storage regimes are critically analysed. The levels of GA in potato can be controlled effectively by adopting appropriate post-harvest practices. Further studies are necessary, however, to investigate best practices, which either check completely or retard substantially their formation. (C) 2008 Society of Chemical Industry.
Resumo:
Background & aims: This study investigated the influence of four commercial lipid emulsions, Ivelip, ClinOleic, Omegaven and SMOFlipid (R), on lipid body formation, fatty acid composition and eicosanoid production by cultured human peripheral blood polymorphonuclear cells (PMN) and mononuclear cells (PBMC). Methods: PMN and PBMC were exposed to emulsions at concentrations ranging from 0.01 to 0.04%. Lipid body formation was assessed by microscopy, fatty acid composition by gas chromatography and eicosanoids by ELISA. Results: Stimulation of inflammatory cells and exposure to lipid emulsions promoted the formation of lipid bodies, but there did not appear to be differential effects of the emulsions tested. In contrast, there were differential effects of lipid emulsions on eicosanoid formation, particularly with regards to LTB4 production by PMN. Omegaven dramatically increased production of eicosanoids compared with the other emulsions in a dose-dependent manner. This effect was associated with a significantly higher level of lipid peroxides in the supernatants of cells exposed to Omegaven. Conclusions: Stimulation of inflammatory cells and exposure to lipid emulsions promotes lipid body formation and eicosanoid production, although the differential effects of different emulsions appear to be largely due to lipid peroxidation of unsaturated fatty acids in some emulsions in this in vitro system. (C) 2009 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
Resumo:
Studies have suggested that diets rich in polyphenols Such as flavonoids may lead to a reduced risk of gastrointestinal cancers. We demonstrate the ability of monomeric and dimeric flavanols to scavenge reactive nitrogen species derived from nitrous acid. Both epicatechin and dimer B2 (epicatechin dimer) inhibited nitrous acid-induced formation of 3-nitrotyrosine and the formation of the carcinogenic N-nitrosamine, N-nitrosodimethylamine. The reaction of monomeric and dimeric epicatechin with nitrous acid led to the formation of mono- and di-nitroso flavanols, whereas the reaction with hesperetin resulted primarily in the formation of nitrated products. Although, epicatechin was transferred across the jejunum of the small intestine yielding metabolites, its nitroso form was not absorbed. Dimer B2 but not epicatechin monomer inhibited the proliferation of, and triggered apoptosis in, Caco-2 cells. The latter was accompanied by caspase-3 activation and reductions in Akt phosphorylation, suggesting activation of apoptosis via inhibition of prosurvival signaling. Furthermore, the dinitroso derivative of dimer B2, and to a lesser extent the dinitroso-epicatechin, also induced significant toxic effects in Caco-2 cells. The inhibitory effects on cellular proliferation were paralleled by early inhibition of ERK 1/2 phosphorylation and later reductions in cyclin D I levels, indicating modulation of cell cycle regulation in Caco-2 cells. These effects highlight multiple routes in which dietary derived flavanols may exert beneficial effects in the gastrointestinal tract. (c) 2005 Elsevier Inc. All rights reserved.
Resumo:
The two major applications of microwave remote sensors are radiometer and radar. Because of its importance and the nature of the application, much research has been made on the various aspects of the radar. This paper will focus on the various aspects of the radiometer from a design point of view and the Low Noise Amplifier will be designed and implemented. The paper is based on a study in radio Frequency Communications engineering and understanding of electronic and RF circuits. Some research study about the radiometer and practical implementation of Low Noise Amplifier for Radiometer will be the main focus of this paper. Basically the paper is divided into two parts. In the first part some background study about the radiometer will be carried out and commonly used types of radiometer will be discussed. In the second part LNA for the radiometer will be designed.
Resumo:
This paper describes the design, implementation and testing of an intelligent knowledge-based supervisory control (IKBSC) system for a hot rolling mill process. A novel architecture is used to integrate an expert system with an existing supervisory control system and a new optimization methodology for scheduling the soaking pits in which the material is heated prior to rolling. The resulting IKBSC system was applied to an aluminium hot rolling mill process to improve the shape quality of low-gauge plate and to optimise the use of the soaking pits to reduce energy consumption. The results from the trials demonstrate the advantages to be gained from the IKBSC system that integrates knowledge contained within data, plant and human resources with existing model-based systems. (c) 2005 Elsevier Ltd. All rights reserved.
Resumo:
The self-assembly of PEGylated peptides containing a modified sequence from the amyloid beta peptide, YYKLVFF, has been studied in aqueous solution. Two PEG molar masses, PEG1k and PEG3k, were used in the conjugates. It is shown that both YYKLVFF–PEG hybrids form fibrils comprising a peptide core and a PEG corona. The fibrils are much longer for YYKLVFF–PEG1k, pointing to an influence of PEG chain length. The beta-sheet secondary structure of the peptide is retained in the conjugate. Lyotropic liquid crystal phases, specifically nematic and hexagonal columnar phases, are formed at sufficiently high concentration. Flow alignment of these mesophases was investigated by small-angle neutron scattering with in situ steady shearing in a Couette cell. On drying, PEG crystallization occurs leading to characteristic peaks in the X-ray diffraction pattern, and to lamellar structures imaged by atomic force microscopy. The X-ray diffraction pattern retains features of the cross-beta pattern from the beta-sheet structure, showing that this is not disrupted by PEG crystallization.