印度Sukinda铬铁矿区水样的重金属污染、理化性质和微生物的评价(英文)

分析了Sukinda铬铁矿采石场及其邻近区域水样的重金属污染及理化性质和微生物含量。铬铁矿的水样含有高浓度重金属,其浓度顺序为Cr>Fe>Zn>Ni>Co>Mn,然而该地区的地下水除了Fe以外并没有受到重金属污染。矿井水样的理化参数与正常水的有差别。与相邻矿水样相比,矿井水样含有一些低浓度的微生物种群,包括细菌、真菌和放线菌。金属浓度与相关的理化参数显示了他们之间有正、负响应,而金属浓度和微生物种群之间表现出了负的相关性。从铬铁矿废水中纯化出来的菌株对铬和其他的重金属以及抗生素表现出高的耐受性,可作为重金属污染的指示剂。     

搅拌摩擦对接焊6061铝合金的高周疲劳行为（英文）

对6061铝合金进行搅拌摩擦对接焊,其焊接工艺参数为:旋转速度600、800、1000、1200 r/min,前进速度80、100 mm/min,探针插入深度1.85 mm。基于搅拌摩擦焊参数计算得到的能量输入结果表明,在输入能量为196~405 kJ的情况下,接头在297~354 kJ的输入能量范围内有最大的抗拉强度。在不同的应力比(R=0.5,0.3,0.1,-0.3,-0.5)下,将高强度、低强度2种焊接头进行疲劳测试。结果表明,对于这2种焊接头,显微组织特征明显影响其疲劳性能,比如搅拌区、热力影响区(TMAZ)和热影响区。从接头的显微组织、裂纹扩展路径和断裂表面观察等方面对其疲劳强度进行讨论。     

Effect of extrusion on properties of Al-based composite

An aluminium alloy and its composite with dispersed SiC particles made by liquid metallurgy route were extruded under optimized conditions.The properties were characterized in terms of microstructure,hardness and sliding wear behaviour and then compared between the extruded and cast alloys and composites,in order to understand the benefits of composite and extrusion on the alloy.It was observed that composites drastically increased the hardness and the extruded composites further increased this value.The advantage of composites was realized in sliding wear tests.     

Seventeen-lump model for the simulation of an industrial fluid catalytic cracking unit (FCCU)

A 17-lump kinetic model has been developed for the riser–reactor cum regenerator of a fluid catalytic cracking unit (FCCU). This accounts for cracking, hydrogen transfer, aromatization, isomerization, alkylation and dimerization, as well as catalyst deactivation due to the coke deposition in its pores. A model for the industrial combustor–regenerator unit is also developed. The lumping scheme includes the detailed characterization in terms of the paraffins, naphthenes and aromatics (PNAs) for the VGO feed and also the detailed compositions of the two important products: gasoline and LPG. A total of 199 kinetic parameters for the riser–reactor cum regenerator have been fitted (tuned) using 192 sets of plant data (under different operating conditions) from an industrial FCC unit. The tuned model of the integrated FCCU was run for 15 additional operating conditions. The match was found to be quite good.     

Multi-stage,multi-facility,batch production system with deterministic demand over a finite time horizon

Researches on multi-stage production systems, so far, have tended to schedule production according to the overall optimal batch size of the entire shop with little consideration of the influence of the individual stages of production on the batch sizes that are considered optimal. The authors have attempted, in this paper, to investigate the effects of scheduling according to the optimality of the respective production stages. The results are compared with those of the more common case of overall optimal batch scheduling     

Dilatometric Sintering of Ti-2A1 and Ti-5AI Elemental Powders

The effect of Al addition (2 and 5 at. pct) on sintering kinetics of Ti power were investigated. Al reduces the sintering rates, sinter density, increases activation energy of sintering and accelerates the grain growth. Sintering was controlled by mixed mode, i.e. transient liquid phase sintering, formation of intermetallics, and Ti grain boundary diffusion in TiAl2 and other intermetallics.     

CASHeW: Cluster-based Adaptive Scheme for Multimedia Delivery in Heterogeneous Wireless Networks

Multimedia streaming over heterogeneous wireless networks has attracted significant interest in recent years from both telecom network operators and end users. However, the heterogeneity of the wireless network makes it very difficult to synchronize real-time multimedia streaming to different types of end-user devices across different wireless networks. In addition, with different delay and packet loss across different networks, multimedia delivery over the heterogeneous wireless networks cannot provide good quality streaming video. This paper proposes CASHeW—a novel cluster-based design with an in-built feedback-based adaptive mechanism that results in a higher video perceived quality in two-hop heterogeneous wireless network environments. CASHeW employs a proxy-client-server mechanism between the base station (BS) and the end-user; and importantly uses a quality-oriented adaptive scheme for efficient multimedia delivery. Simulation-based tests indicate that the performance of CASHeW not only outperforms transport layer adaptive delivery protocols like the TCP-Friendly Rate Control Protocol (TFRCP) and Loss Delay Adaptation (LDA+), but also is better than that of medium access control (MAC) layer protocols such as the Receiver Based Auto Rate (RBAR) and Enhanced Distributed Channel Access (EDCA) in terms of average perceived quality, average bit rate and loss rate.     

Determination of iodine-bromine numbers of some edible oils with two N-bromoimides

The iodine-bromine numbers of some edible oils such as coconut oil, gingelly oil, groundnut oil, mustard oil, olive oil, palm oil and sunflower oil were determined titrimetrically using the N-bromoimides, N-bromophthalimide (NBP) and N-bromosaccharin (NBSA). The proposed excess-back titration methods were based on quantitative bromination of the glycerides of unsaturated fatty acids present in the oils and both the methods were simple, rapid and accurate.     

Operator training in a repetitive production task— a comprehensive approach

For a repetitive production task, a comprehensive operator training method was developed through the use of MTM analysis, operator instruction sheet, demonstration, practice session, feedback and guidance. At the end of 72 minutes demonstration and practice session, all the operators were able to perform the assigned drilling task by employing the prescribed motions and came close to reaching the measured production standard. The average quantity and quality output increased from the draft to the fourth quarter (15-minute) by 25 and 37%, respectively. Statistically the improvement was highly significant.     

Electrowinning of Copper in the Presence of Anodic Depolarisers - A Review

Abstract

Alternative anodic reactions have been investigated to reduce the cell voltage and hence energy consumption in the electrowinning of copper. It is necessary to avoid oxygen evolution reaction at the anode, which requires a high potential of 2 V in order to reduce the cell voltage. An extensive literature review reveals that the cell voltage can be reduced by using various ionic couples, such as Fe²⁺/Fe³⁺, Cu²⁺/Cu¹⁺. Addition of cobalt, soluble sulfites and sulfur dioxide to the electrolyte modifies the anodic reaction. Examination of several electrode materials for anodic oxidation confirms that graphite is the most suitable material. Some fundamental studies on the anodic oxidation of sulfur dioxide have also been reviewed.