Microscale investigation of thin film surface ageing of bitumen

This paper investigates the mechanism of bitumen surface ageing, which was validated utilizing the atomic force microscopy and the differential scanning calorimetry. To validate the surface ageing, three different types of bitumen with different natural wax content were conditioned in four different modes: both ultraviolet and air, only ultraviolet, only air and without any exposure, for 15 and 30 days. From the atomic force microscopy investigation after 15 and 30 days of conditioning period, it was found that regardless the bitumen type, the percentage of microstructure on the surface reduced with the degree of exposure and time. Comparing all the four different exposures, it was observed that ultraviolet radiation caused more surface ageing than the oxidation. It was also found that the combined effect was not simply a summation or multiplication of the individual effects. The differential scanning calorimetry investigation showed that the amount of crystalline fractions in bitumen remain constant even after the systematic conditioning. Interestingly, during the cooling cycle, crystallization of wax molecules started earlier for the exposed specimens than the without exposed one. The analysis of the obtained results indicated that the ageing created a thin film upon the exposed surface, which acts as a barrier and creates difficulty for the wax induced microstructures to float up at the surface. From the differential scanning calorimetry analysis, it can be concluded that the ageing product induced impurities in the bitumen matrix, which acts as a promoter in the crystallization process.     

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.     

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。     

搅拌摩擦对接焊6061铝合金的高周疲劳行为

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。     

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。     

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     

Rectification and recognition of text in 3-D scenes

Real-world text on street signs, nameplates, etc. often lies in an oblique plane and hence cannot be recognized by traditional OCR systems due to perspective distortion. Furthermore, such text often comprises only one or two lines, preventing the use of existing perspective rectification methods that were primarily designed for images of document pages. We propose an approach that reliably rectifies and subsequently recognizes individual lines of text. Our system, which includes novel algorithms for extraction of text from real-world scenery, perspective rectification, and binarization, has been rigorously tested on still imagery as well as on MPEG-2 video clips in real time.Received: 15 December 2003, Published online: 14 December 2004Gregory K. Myers: Correspondence to     

Corrosion Behavior of MIG Brazed and MIG Welded Joints of Automotive DP600-GI Steel Sheet

Galvanized dual-phase steel sheets are extensively used by the auto industry for their corrosion resistance property. Welding by the metal inert gas (MIG) process causes degradation of the steel in the vicinity of the joint due to excessive zinc evaporation. In order to minimize Zn loss, the MIG brazing process has been tried out in lap joint configuration over a heat input range of 136–204 J mm^?1. The amount of zinc loss, intermetallic formation and corrosion properties in the joint area has been evaluated for both MIG brazing and MIG welding. Corrosion rate of 21 mm year^?1 has been reduced to 2 mm year^?1 by adopting MIGB in place MIGW. Impedance study has shown that the corrosion mechanism in base metal, MIG brazed and MIG welded joints is dominated by charge transfer, diffusion and mixed mode control processes, respectively.     

Mathematical Transforms in Design: Case Study on Feedback Control of a Customizable Automotive Suspension

Engineering design and analysis is replete with examples of mathematical transforms. This paper discusses the use of mathematical transforms at the operational stage implemented by superimposing the system with a control system to (1) convert a decoupled or coupled system to uncoupled, (2) achieve robustness to noise factors and (3) eliminate imaginary complexity. This paper proves with examples that such controller design and implementation is much easier for an uncoupled or decoupled design as compared to a coupled design. The case study presents a new customizable automotive suspension with independent control of stiffness, damping and ride-height. This system was proposed, designed and built using axiomatic design principles. The mechanical design is decoupled with respect to the functional requirements (FRs) of stiffness and ride-height; moreover ride-height is affected by the load on the vehicle (noise factor). This paper presents the design and implementation of a feedback control system for the customizable suspension to uncouple the system and to make it robust to the noise factor.