Evaluation of Material Biodegradability in Real Conditions–Development of a Burial Test and an Analysis Methodology Based on Numerical Vision

This work validated a burial protocol for in situ testing and presents a robust, repeatable and time-saving technique to measure degraded areas in the sample, i.e. an image analysis method. 1440 specimens of degraded samples have been compiled in a data base. To this end, twenty samples presenting different levels of biodegradability (i.e. PHBV/HV, PLA, PCL, PCL-Starch, paper, PE, PE-Starch) were buried at 4 different locations and then disinterred at 4, 6, 9, 12, 18, and 24-month intervals. The biodegradation levels of these samples were determined by computing weight and area loss. Weight loss was measured after careful cleaning, whereas area loss was quantified using image analysis. Image analysis gives reliable information on visual pollution while only requiring a rudimentary and thus quicker cleaning of the samples.     

Technetium: A toxic waste product of the nuclear fuel cycle: Effects on soybean growth and development

Technetium-99 (⁹⁹Tc) is formed in significant amounts (6.2% fission yield) during fission in both nuclear reactors and nuclear bombs. The effects of technetium on soybeans (Glycine max) were studied in relation to (a) cytochemical events in the apical meristems of germinating seedlings; (b) growth responses to 0, 0.04, 0.2, 1.0, 5.0, and 20.0 ppm Tc; (c) growth responses to varying levels of Tc after a prior 5-day germination on Tc-free media, and (d) response to Tc in the presence of added manganese.By 20 days, reductions in growth were evident at all levels of Tc except 0.04 ppm (Experiment 2). Root growth was most severely affected, and seedling abnormality at 20 ppm was fivefold greater than that of the controls. The effect of 20 ppm Tc was evident at 10 days when the accumulated absorption dose was approximately 25 rads. The first evidence of damage at this dose was a delay in the initiation of the first trifoliate leaf. The shoot meristem size was 1.2-fold smaller than that of the control; however, there was no cytological evidence of radiation-induced damage. Observation of mitotic figures did not reveal any chromosome aberrations, micronuclei, or chromosome bridges. The lowest level of Tc showing toxicity was 0.2 ppm which resulted in a 31% reduction in growth at 20 days. The accumulated dose was 0.5 rad (0.025 rad/day) and thus it seems unlikely that the rapid inhibition of growth and development is due to radiological toxicity. It is quite probable that the growth effects are due to chemical toxicity possibly due to nutrient competition and/or substitution in uptake or metabolism. However, extremely low doses of radiation have been shown to delay the onset of DNA synthesis (possibly by membrane effects) inTradescantia and until the actual mechanism of Tc inhibition is determined a radiation effect cannot be totally ruled out.This research was partially supported by ERDA Contract EY-76-S-02-4139     

宝鸡市生态城市建设评价

结合生态城市的相关理论和不同学者的研究,遵循生态城市评价指标选择的原则和研究区域的实际情况,从经济、社会和自然三方面建立了宝鸡市生态城市建设的评价指标体系。通过采用熵权法确定各评价指标的权值,对宝鸡市近几年的生态城市建设进行了简要评价。结果表明,2004—2008年宝鸡市的生态城市建设十分成功,但在集中力量建设生态环境的同时,忽略了对城市的经济建设,使宝鸡市的经济结构开始出现不合理现象。建议宝鸡市在大力建设生态城市的同时,要集中力量在经济建设方面,以达到自然、经济与社会和谐发展的目的。     

热闷钢渣用单轨移动罩车的设计

根据钢渣热闷工艺要求进行单轨移动罩车的结构设计与行走装置的设计,通过三维建模软件及理论力学分析计算此罩车的配重及质心,使罩车与导向装置接触处的压力最小,且罩车施加给低地轨的横向静摩擦力最小。通过此方法设计的单轨移动罩车能大大改善钢渣热闷厂房的工作环境,减少厂房的腐蚀,提高厂房屋顶的寿命周期。     

基于改进组合赋权-TOPSIS模型的农村污水处理设施效果评价

农村生活污水处理设施运行效果的优劣关系农村环境综合整治、乡村振兴战略规划目标的实现.为分类评价农村污水处理设施运行效果,从经济、技术和管理3个层面确定了12项评价指标,建立了农村污水处理设施效果评价指标体系;并利用多准则决策理论,构建了基于模糊层次分析法（FAHP）、改进熵权法和逼近理想解排序法（TOPSIS）的农村污水处理设施效果评价模型,对农村污水处理设施效果进行评价研究.选取15座农村污水处理设施作为评价对象,分规划设计和运行管理两阶段,开展设施效果评价,对评价对象进行优劣排序,验证该方法的可行性.结果表明,建立的农村污水处理设施评价指标体系和构建的评价方法具有较高实践可行性和较强实际适用性;评价方法较好地区分了规划设计阶段和运行管理阶段重要的考量指标;实际案例验证中规划设计阶段和运行管理阶段均是XBT污水处理站排名最高（相对贴近度分别为0.9137、0.8961）,DYZ污水处理站排名最低（相对贴近度分别为0.2759、0.2961）,计算结果与实际情况一致.研究结果可为本区域农村污水处理设施规划设计和运行管理提供技术支撑,为同类地区农村污水处理设施评价提供技术参考.     

区域污染源排污总量分配方案初探

文章以实现区域可持续发展为目标,对区域污染物排污总量的分配进行了初步探索,通过分析对其有影响的各种因素,最终为特定区域发展规划的制定,可持续发展的实现,提供了一种较好的污染物排污总量分配方案。     

Effects of mid-trimester induced abortion on the subsequent pregnancy

The outcome of the pregnancy following (a) a mid-trimester termination of pregnancy (TOP) for fetal neural tube defect (NTD) (77 women=group 1); (b) mid-trimester TOP for fetal Down's syndrome (13 women=group 2); (c) delivery of a baby with NTD (119 women=group 3) was studied. The prenatal fetal loss was relatively high in all groups. In group 1 it was similar to that found in other studies after first trimester TOP, in group 2 it was associated with advanced maternal age and the unexpected finding in group 3 was not attributable to advanced maternal age. It is suggested that a previous NTD per se might increase the risk of fetal loss in the next pregnancy. A previous mid-trimester TOP for NTD was not associated with an increase in premature labour, small for dates babies or congenital abnormality in the next pregnancy, but there was a slight increase in the number of babies weighing less than 2500 g.