Life cycle environmental performance and improvement of a yogurt product delivery system

A life cycle assessment was conducted to evaluate the environmental performance of the yogurt product delivery system used by Stonyfield Farm. A life cycle model was developed which included material production, manufacturing and disposition for primary and secondary packaging, as well as the related transportation links between these stages and filling, retail and the point of consumption. Product delivery systems (PDS) that utilized 4, 6, 8 and 32 oz polypropylene (PP) cups and 2 oz linear low‐density polyethylene (LLDPE) tubes were analysed. Ten strategies for improving the environmental performance of these systems were proposed and their impacts on the total life cycle burden were analysed. The life cycle energy consumption for the 2, 4, 6, 8 and 32 oz containers was 4050, 4670, 5230, 4390 and 3620 MJ/1000 lb yogurt delivered to market, respectively. Material production of the primary packaging accounted for 58% of the life cycle energy, while Distribution 3 (yogurt delivery to distributors/retailers) alone accounted for one‐third of the life cycle total energy. The life cycle solid waste profile showed that as the container size decreased, the solid waste burden increased, from 27.3 kg (32 oz) to 42.8 kg (6 oz) per 1000 lb yogurt delivered to market. This relationship was even more pronounced for the 4 oz (47.5 kg) and 2 oz (56.2 kg) product delivery systems. The greatest potential improvements in the environmental performance of the PDS are achievable through redesigning the primary packaging and using alternative manufacturing techniques for the yogurt cups. Shifting from injection moulding to thermoforming of 32 oz container reduces the life cycle energy and solid waste by 18.6% and 19.5%, respectively, primarily due to light‐weighting. Elimination of lids for 6 oz and 8 oz containers provided similar benefits. Consumers purchasing yogurt in 32 oz instead of 6 oz containers can save 14.5% of the life cycle energy and decrease solid waste by 27.2%. Copyright © 2004 John Wiley & Sons, Ltd.     

球团法处理冶金废料

介绍了两种处理冶金废料的方法：冷固结团块法和微型竖炉球团法。冷固结团块法系采用氧化焙烧一冷固结团块工艺，这种方法可有效地除去废料中杂质，生产出的团块质量好；微型竖炉球团又分鼓风竖炉和抽风竖炉两种工艺。两种竖炉均可生产出质量良好的球团矿，两种方法实践证明，技术上是可行的，经济上是合算的。团块和球团矿符合转炉炼钢的要求。     

24m2沸腾炉系统余热锅炉的改进

余热锅炉是一种非标设计、非标制作的锅炉，它运行的好坏与其所配置的冶金炉烟气性质有着非常密切的关系。本介绍了我厂24m^2锌焙烧沸腾炉余热锅炉在结构及配置等方面进行改进前后的不同状况。     

Marine Wastewater Discharges from Multiport Diffusers. II: Unstratified Flowing Water

Laboratory experiments on the near-field mixing of buoyant plumes discharged from multiport diffusers into unstratified flowing water are reported. The spatial variation of dilution was measured by a newly developed three-dimensional laser-induced fluorescence system and a microconductivity probe. The near-field hydrodynamics are complex. The plumes discharged upstream dilute and merge more rapidly than those discharged downstream. Even with wide port spacing, the plumes eventually merge to form a laterally uniform surface wastefield. The density profile in this wastefield becomes gravitationally stable and suppresses mixing, marking the end of the near field. The value of the port spacing ratio, s/H, below which the discharge approximates a line plume is greater for discharge into a flowing current than into a stationary environment, so the port spacing plays a lesser role in a flowing current. The mixing and dilution that occurs in the surface layer is less than for a discharge into a stationary environment, and it decreases as the current speed increases. Semiempirical equations to predict the major near field characteristics are presented.     

聚变驱动次临界堆双冷嬗变包层第一壁结构热应力计算与分析

使用有限元程序对聚变次临界堆双冷嬗变包层第一壁进行数值模拟 ,给出不同载荷条件下的温度场和应力场分布 ,结果证明典型氦气系统设计满足热工要求。依据数值模拟结果对第一壁氦气载热能力进行分析 ,并考虑了流道形状对结构热应力的影响。     

餐厨垃圾发酵生产乳酸的工艺优化

为提高餐厨垃圾发酵生产乳酸的效率,采用Plackett-Burman和中心复合两种统计试验方法对影响发酵的因素进行初筛和优化.Plackett-Burman实验的结果表明,影响乳酸发酵的正向显著性因素有乳酸菌TD175、糖化酶、吐温80、纤维素酶;灭菌是负显著性因素.通过中心复合试验设计,确定最佳发酵工艺:乳酸菌接种量6.6%,糖化酶160U/g,纤维素酶60U/g,吐温800.08%,温度45℃.最佳工艺条件下发酵40h,乳酸产量能达到66.13g/L,每克干垃圾产乳酸0.53g.餐厨垃圾的乳酸发酵无需灭菌、无需额外营养物,具有良好的经济效益和应用前景.     

利用铜尾矿烧制水泥熟料的技术研究

利用给定铜尾矿在系统分析的基础上,掺加其它一些原料,在实验室烧制高标号水泥熟料。     

国际核电发展动态及我国核电发展的思考

随着世界性金融危机引发的全球经济衰退,使人们更加坚信核能发电在保障能源供应和平抑能源市场价格波动方面的重要作用,核电建设必将进入迅速发展阶段.中国作为资源耗量多的国家,一定会及时跟进,加快核电建设,这样一来,将为国家带来丰厚的经济利益,同时也将有效解决资源过分利用和环境保护的问题,产生良好的社会效益.     

放射性废物焚烧设备及工艺应用进展

热解焚烧是处理放射性有机废物的重要工艺,能大幅提高废物处理的体积。由于现有焚烧炉设备建成时间较早,且放射性废物种类增加,其运行和维护保养都面临新的挑战。本文概述了国内外放射性焚烧炉的发展现状和工艺特点,对焚烧炉运行中的问题进行归类,并展望未来的改进方向。     

水泥窑协同处置危险废物工艺影响研究

水泥窑协同处置危险废物具有热容量大、停留时间长、成本低、无废渣排出及处理彻底等技术优势,成为危废资源化利用和无害化处置的有效补充。本文从水泥窑工艺安全、产品质量等角度分析影响水泥窑协同处置危废稳定运行的影响因素,提出了保证水泥窑协同处置危废系统连续稳定运行的相应措施。