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《钢铁冶炼》2013,40(8):597-602
AbstractIn the last decades the European steel industry has made continuous efforts to reduce residues and byproducts and to increase recycling in order to reduce its environmental impact. While some steelmaking slags have been widely characterised and, to a certain extent reused, ladle furnace (LF) slag is used in different applications because of its specific properties. The main purpose of the case study presented in this paper concerns the reduction of potential LF slag environmental impacts, because of its intrinsic physicochemical properties. During the handling and cooling of LF slag, it disintegrates into a powder due to instability of the dicalcium silicate, causing an increase in dust emissions to the environment. The approach presented in this paper aims to reduce this phenomenon in order to achieve a more sustainable solution in term of reduction of powder dispersion in the environment, of costs saving and of nuisance reduction in the surroundings areas. 相似文献
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《应用陶瓷进展》2013,112(2):88-98
AbstractThe development of robust methods for determining fracture toughness and for interlaboratory assessment of results is discussed with respect to procedural standardisation. Acceptable methods are based on meeting several criteria, including ease and cost-effectiveness of testpiece manufacture, the method of introducing a sharp precrack and the acceptability of appropriate fracture toughness analysis. The four simplest methods meeting these criteria are reviewed in detail, together with information on their reproducibility gathered during international round robin exercises. Not all these methods are effective on all materials, and users need to be aware of their limitations. Details of calibration equations and some experimental nuances are given. 相似文献
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《钢铁冶炼》2013,40(1):35-40
AbstractThe purpose of this study was to develop a product design model for estimating the impact toughness of low alloy steel plates. The rejection probability in a Charpy V test is predicted with process variables and chemical composition. Joint modelling of the mean and deviation was used in order to improve the results. The proposed method is suitable for the whole production line, including all grades of steel in production and it is not restricted to a few test temperatures. Using the proposed model the product design group could have recognised most of the rejections before production. Next, the developed model will be implemented into a graphical simulation tool that is in daily use in the product planning department and already contains some other mechanical property models. The model will guide designers in predicting the related risk of rejection and in producing desired properties in the product at lower cost. 相似文献
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AbstractBeginning as early as the 1960s, concerns were voiced as to the adequacy of the package test standards imposed by the transport regulations promulgated by the International Atomic Energy Agency. One concern that was frequently raised and has continued to the present time is that the test standards do not necessarily simulate real accidents. The purpose of the crash tests described here that were done with typical packages carried in full scale vehicles was to assess the IAEA standards, their adequacy and to suggest changes to them that might be needed. It was also hoped that the tests, which were performed in the USA and in the UK, would show to regulators, to users of the regulations and to the public that current regulations already provide a very high level of safety for real world accidents. With time, much of the original information regarding these tests and their results has been lost. The few documents that remain have been surveyed and this paper presents summaries from this survey of the tests and their results. 相似文献
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A series of polypropylene-fibre continuous-filament yarns was used to manufacture a set of simplified carpet-like structures. Recovery and wear tests on these samples are described and the results compared with those of single-filament recovery tests discussed in Parts I and II of this series. It is concluded that single-filament testing can indicate very poor or very good yarns, although unconsidered effects dominate the performance of intermediate samples. 相似文献
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《International Journal of Cast Metals Research》2013,26(1-4):31-38
AbstractThis study aims to clarify the influence of additive elements of Ni and Mn on tensile and impact properties of three kinds of spheroidal graphite cast irons (SG irons), which are as cast, annealed and austempered samples. Spheroidal graphite cast irons with Ni (0–4˙5 mass-%) and Mn (0–0˙5 mass-%) melted by a high frequency induction furnace and cast into a Y block CO2 mould with 30 mm in thickness. From the viewpoint of heat treatment, tensile strength and hardness of SG irons become larger in the order of ferritised<as cast<austempered ones. Matrix structures of SG irons, which are conducted to austempering treatment from α and γ mixture range, consists of bainitic ferrite with high toughness. Austempered SG iron with 3%Ni in 0˙1%Mn series is found to become higher tensile strength compound with elongation and toughness of 901 MPa, 17% and 915 kJ m?2. 相似文献
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《Science & Technology of Welding & Joining》2013,18(3):335-338
AbstractVibration of welded parts is usually applied to achieve effects similar to thermal stress relief. With vibration, it is not only residual stresses that are affected. Using two different welding processes, the influence of vibration on hardness and toughness of the weld was measured. For each welding process, two series of Charpy specimens were made over the temperature range from -60 to +20°C. The only difference between the two series was in performing welding with or without vibration. Slight differences in weld metal hardness were observed. Toughness measurements show an increase in impact toughness and a significant increase in fracture toughness in samples which were vibrated during welding. 相似文献
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《塑料、橡胶和复合材料》2013,42(1):43-53
AbstractAn extensive study of the fibre orientation structures developed in a transverse ribbed plate during injection moulding, and the use of these structures to investigate the effect of local fibre orientation state on crack initiation resistance, is reported. The fibre orientation results for the ribbed plate, measured using large area image analysis system developed at Leeds University, showed that after an initial settling down period, the central core region, where the fibres are aligned perpendicular to the flow direction, decreased in size monotonically, with an associated monotonic increase in the outer shell regions, where the fibres are aligned preferentially along the injection direction. Interestingly, the level of orientation in the two regions remained almost constant: only the proportions of the two regions were found to change with flow length. Across the plate, close to the gate, the central core region was found to have a lens-like shape, while at the other end of the plate the core was thinner and also consistent in thickness across the sample width. The transverse rib was found to cause little disturbance to the fibre orientation of the base plate. The different proportions of the shell and core regions at different locations over the ribbed plate provided an ideal case to test the proposition of Friedrich that the crack resistance of a short fibre reinforced material depends on the number of fibres that are perpendicular to the crack tip. The impact test results gathered in this way confirmed this hypothesis of Friedrich. 相似文献
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ABSTRACTThis paper assesses the potential role of investments in irrigation in Sub-Saharan Africa in improving food security and self-sufficiency in the region. Focusing on the region’s drylands, the study identifies a potential for expanded irrigated area of 6–14 million hectares (ha), depending on technology costs and other factors. Linkage of these results with a global agricultural trade model shows that accelerated irrigation investment can effectively reduce growing food import dependency from 54% under a business-as-usual scenario to a much smaller 17–40%; and can also reduce the population at risk of hunger and child under-nutrition. 相似文献