Performance evaluation of reverse logistics enterprise – an agent-based simulation approach

Reverse logistics (RL) has been applied in many industries and sectors since its conception. Unlike forward logistics, retracing consumer goods from the point of consumption to the point of inception is not a well-studied process. It involves many uncertainties such as time, quality and quantity of returns. The returned products can be remanufactured, have parts harvested, or be disposed safely. It is important to implement these activities in a cost-effective manner. The aim of this research is to measure the performance of the RL enterprise with the help of an agent-based simulation model. The major entities in the RL network are considered as Agents that can act independently. There are several different agents: collector agent, sorting-cum-reuse agent, remanufacturing agent, recycler agent, supplier agent and distributor agent. The individual performances of the agents are measured and recommendations are given to improve their performance, leading to the enhancement of the total performance of the RL enterprise. The approach is applied to a case study involving cell phone remanufacturing.     

废旧轮胎再制造过程的环境污染及防治研究

随着汽车和轮胎行业的迅速发展,由此产生的废旧轮胎也逐年增加。废旧轮胎再利用技术既可解决橡胶资源短缺问题,又能消除黑色污染,是循环经济的重要环节,在推广这一技术的同时,应注意其伴生的环境污染。再利用生产主要分为清洗、打磨、粘中垫胶、粘预硫化胎面、低温硫化等步骤。此过程将产生粉尘、非甲烷总烃废气、橡胶颗粒以及清洗废水等污染物。应对这些污染物采取有效的治理措施,使其满足达标排放和无害化的要求,以达到经济利益和环境保护的双赢。     

Two-echelon closed-loop supply chain deterministic inventory models in a batch production environment

This paper considers a two-echelon closed-loop supply chain consisting of a manufacturer and a remanufacturer at the upper echelon and a retailer at the lower echelon. The retailer faces a constant demand from customers, which is satisfied through recovered and new products received from the remanufacturer and the manufacturer, respectively. The manufacturer produces the product with finite rate, whereas the recovery of returned product is instantaneous at the remanufacturer. We develop three models to determine the optimal production-inventory policy of the players for minimizing the joint total cost of the system. In the first model, the retailer receives the product in batches from the manufacturer and the remanufacture simultaneously, whereas in the second and third models, the batches are received alternatively. In the third model, however, the procurement of raw material at the manufacturer is also considered. Numerical illustration is presented to examine the impact of certain key parameters.     

废弃轮胎制备中孔炭吸附材料工艺及性能研究

为了解决废弃轮胎造成的资源浪费和环境污染的问题,对以废弃轮胎橡胶为碳的前驱体原料,制备具有高吸附性能中孔炭材料工艺进行了系统的研究。通过XRD、扫描电镜以及比表面积分析,对制备的中孔炭微观结构和性能进行表征,讨论了炭化温度、碱炭比,以及活化温度和活化时间等工艺条件对制备中孔炭的产率、结构和性能的影响。结果表明,通过改变工艺条件制备的中孔炭的孔径分布可以在2~80 nm范围内进行调控。在500℃炭化温度,碱炭比为4∶1,900℃活化1 h的工艺条件下,制备的中孔炭的比表面积为473 m2/g,对甲基橙的最大吸附量达到254 mg/g。     

再制造工程——末端产品最佳资源化方式

再制造工程是一种末端产品的资源化利用方式。阐述了再制造工程的内涵、在全生命周期中的地位及国内外发展现状，分析了再制造所能够带来的巨大的资源效益、经济效益、社会效益和环境效益，得出结论：再制造工程是末端产品进行资源化处理的最佳利用方式。     

绿色再制造工业发展综述

绿色再制造工业是一个新兴工业，能够生产低价格、高品质、高环保的产品来满足公众需求，并为社会发展节约大量能源和材料。绿色再制造工业能够使社会财富进入健康的增长和可持续发展时期。通过综述再制造工业的发展历史、现状和巨大效益，提出再制造业的发展趋势，为再制造工业的研究提供有益参考。     

用VB6.0开发AutoCAD2000的轮胎模排字系统

介绍了以VB6 .0为开发环境 ,运用ActiveXAutomation提供的接口进行AutoCAD的二次开发 ,重点阐述了用VB来开发AutoCAD轮胎模排字系统的算法和步骤 ,并给出了部分代码和例证 ,实践应用效果良好     

Fuel from waste tyres and particulate matter emitted from the process

The interest in obtaining alternative fuels from waste sources and at the same time diminishing the impact of waste disposal has drawn attention to scrap tyres' carbon recovery. In order to thermally degrade used tyre rubber, a laboratory pyrolysis system was developed in this work. The installation devised focused on the production of liquid pyrolysates, where shredded rubber was supplied as the feedstock and nitrogen used as the carrier gas to provide an oxygen-free atmosphere. The variables affecting the performance of the process were investigated, including target temperature, heating rate and total residence time. Characterization of the volatile matter released was conducted by means of mass spectrometry to determine the composition of products, and particulate matter analysis to ascertain the aerosol content in the gas stream. The reproducibility of experiments, the influence of the temperature and time, and differences between the vapours before condensation and the exhaust gases are discussed. This work identified that the larger hydrocarbon fragments condense to constitute the oils, whereas the lighter molecules remain as non-condensable gases. This work also identified that the total number of nano-scale particles carried by the exhaust stream varies with temperature; significant changes in the composition of products and particle content were reported at approximately 400°C. The high number of nano-scale solid particulate matter present in the exhaust gases suggests that a thorough treatment for that stream would be required to avoid human health hazards.     

Catalytic conversion of waste tyres into valuable hydrocarbons

Tyre recycling has become a necessity because of the huge piles of tyres that represent a threat to the environment. The used tyres represent a source of energy and valuable chemical products. Waste tyres were pyrolysed catalytically in a batch reactor under atmospheric pressure. Calcium carbide was used as a catalyst to explore its effect on pyrolysis product distribution. The effect of temperature, amount of catalyst and time on the yields of the pyrolysed products was investigated. Char yield decreased with increase of pyrolysis temperature while total gas and liquid yields increased. The liquid fraction was obtained with boiling point up to 320 °C. The physical and chemical properties of the pyrolysed products obtained were characterized. The catalytic pyrolysis produced 45 wt.% aromatic, 35 wt.% aliphatic and 20 wt.% of polar hydrocarbons. The distillation data showed that ∼80% of oil has boiling point below 270 °C which is the boiling point for 50% of distilled product in commercial diesel oil. The oil fraction was found to have high gross calorific value; GCV (42.8 MJ kg⁻¹). Its Specific gravity, viscosity, Kinematic viscosity, freezing point and diesel index were also within the limits of diesel fuel. The char residues were studied to investigate their characteristics for use as a possible adsorbent. Surface area of char before and after acid demineralization was determined to determine the adsorptive features for waste water treatment.     

Pollution prevention in the pharmaceutical industry

The pharmaceutical industry traditionally uses complex batch-type processes in the manufacture of medicines, although the production of specific medicines by continuous processes is currently envisaged. Due to the diversity of these processes, it is difficult to define a general set of waste prevention guidelines that would apply to all drug manufacturing. The most applicable methods of prevention can, however, be delineated for each of the five steps in the pharmaceutical manufacturing, i.e. (i) research and development, (ii) chemical synthesis, (iii) natural product extraction, (iv) fermentation and (v) product formulation. Waste streams generally arise from cleaning and sterilising equipment, chemical spills, rejected by-products and the processes themselves. Prevention mainly involves waste reduction by materials substitution, process modification/optimisation, waste stream segregation and solvent waste recycling. These measures are assessed and lead to guidelines for waste minimisation methods according to the waste streams under scrutiny.