青藏铁路行车安全保障信息系统研究

分析了影响青藏铁路行车安全的主要因素 ,基于青藏铁路“快速通过高原 ,减少站点布局 ,减少定员 ,减少劳动强度”的原则 ,提出了建设青藏铁路行车安全保障信息系统的总体设计思想 ,并根据青藏铁路站点分布和自然条件情况 ,提出了青藏铁路行车安全保障信息系统及其各子系统的初步设计方案。利用现代化的传感技术、自动检测技术 ,自动采集设备的运行状态信息及环境因素信息 ,并应用先进的信息处理技术和计算机网络传输技术 ,将各种安全信息传送至调度中心和维修部门 ,实现行车事故的预测与预防     

Successfully applying sparging technologies

Air sparging is an innovative methodology for remediating organic compounds present in contaminated, saturated soil zones. In the application of the technology, sparging (injection) wells are used to inject a hydrocarbon-free gaseous medium (typically air) into the saturated zone below or within the areas of contamination. Two major mechanisms of remediation are engaged/enhanced due to the sparging process. First, volatile organic compounds are dissolved in the groundwater and sorbed on the soil partition into the advective air phase, effectively simulating an in-situ air stripping system. The stripped contaminants are transported in the air phase to the vadose zone, generally within the radius of influence of a standard vapor extraction and vapor treatment system. Second, with optimal environmental conditions, volatile and semivolatile organic compounds may be biodegraded by utilizing the sparging process to oxygenate the groundwater, thereby enhancing the growth and activity of the indigenous bacterial community. Air sparging is a complex multifluid phase process which has been applied successfully in Europe since the mid-1980s. Major design considerations include site geology, contaminant type, gas injection pressures and flow rates, injection interval (areal and vertical), and site-specific biofeasibility parameters. Site-specific geology and biofeasibility are the dominant design parameters. Pilot testing and full-scale design considerations should also be addressed. Mathematical models have been developed to simulate the air flow field during the sparging process and to examine the limitations imposed by site geology. Correct design and operation of this technology have been demonstrated to achieve groundwater cleanup to low part-per-billion contaminant levels. Incorrect design and operation can introduce significant pollution liability through undesirable contaminant migration in both the dissolved and vapor phases.     

Can new passenger cars reduce pedestrian lower extremity injury? A review of geometrical changes of front-end design before and after regulatory efforts

Objective: Pedestrian lower extremity represents the most frequently injured body region in car-to-pedestrian accidents. The European Directive concerning pedestrian safety was established in 2003 for evaluating pedestrian protection performance of car models. However, design changes have not been quantified since then. The goal of this study was to investigate front-end profiles of representative passenger car models and the potential influence on pedestrian lower extremity injury risk.

Methods: The front-end styling of sedans and sport utility vehicles (SUV) released from 2008 to 2011 was characterized by the geometrical parameters related to pedestrian safety and compared to representative car models before 2003. The influence of geometrical design change on the resultant risk of injury to pedestrian lower extremity—that is, knee ligament rupture and long bone fracture—was estimated by a previously developed assessment tool assuming identical structural stiffness. Based on response surface generated from simulation results of a human body model (HBM), the tool provided kinematic and kinetic responses of pedestrian lower extremity resulted from a given car's front-end design.

Results: Newer passenger cars exhibited a “flatter” front-end design. The median value of the sedan models provided 87.5 mm less bottom depth, and the SUV models exhibited 94.7 mm less bottom depth. In the lateral impact configuration similar to that in the regulatory test methods, these geometrical changes tend to reduce the injury risk of human knee ligament rupture by 36.6 and 39.6% based on computational approximation. The geometrical changes did not significantly influence the long bone fracture risk.

Conclusions: The present study reviewed the geometrical changes in car front-ends along with regulatory concerns regarding pedestrian safety. A preliminary quantitative benefit of the lower extremity injury reduction was estimated based on these geometrical features. Further investigation is recommended on the structural changes and inclusion of more accident scenarios.     

Rapid growth of environmental research in China

正Environmental research in China has grown tremendously over the last thirty years.This rapid and sustained growth has been supported by the remarkable increases in research funding,the number of graduate students,the degree-offering programs in environmental sciences and engineering,the state-of-the-art facilities,and international collaboration.In 1986 when the National Natural Science Foundation of     

Professor William R. Cullen and arsenic chemistry

正This special issue of the Journal of Environmental Sciences honors Professor William R.Cullen for his outstanding contributions to synthetic chemistry,environmental chemistry,microbiology,and toxicology of arsenic and its compounds.It is very fitting that the papers in this issue cover a diverse range of topics of arsenic     

震后灾区重建城镇生活垃圾的无害化处理对策

针对生活垃圾所产生的环境危害,及其处理过程中存在的二次污染,结合我国城镇发展过程中生活垃圾处理方面存在的问题,提出了灾区震后重建城镇生活垃圾综合处理的无害化对策。     

苏州市生活垃圾焚烧飞灰水泥窑煅烧资源化示范工程

生活垃圾焚烧飞灰水泥窑煅烧资源化利用项目是十一五国家科技支撑计划苏州城市循环经济发展共性技术开发与应用研究子课题之一。该课题目标要求在苏州建成一套日处理30 t焚烧飞灰的水泥窑煅烧资源化示范工程,二恶英分解破坏率大于99.99%,重金属总固定率不小于80%,不影响水泥熟料产品质量,混凝土制品式样按国家标准浸出方法测试结果满足地下水三级质量标准要求,产生的废水、废气达到排放标准。     

Assessment of toxicity potential of metallic elements in discarded electronics: A case study of mobile phones in China

The electronic waste (e-waste) is increasingly flooding Asia,especially China.E-waste could precipitate a growing volume of toxic input to the local environment if it was not handed properly.This makes the evaluation of environmental impact from electronics an essentially important task for the life cycle assessment (LCA) and the end-of-life management of electronic products.This study presented a quantitative investigation on the environmental performance of typical electronics.Two types of disposed mobile...     

Effects of the interactions between selenium and phosphorus on the growth and selenium accumulation in rice (Oryza sativa)

The solution culture, paddy soil culture and the simulation experiments in the laboratory were conducted to clarify the interactions between selenium and phosphorus, and its effects on the growth and selenium accumulation in rice. Results revealed that a suitable supply of selenium could promote rice growth and excessive selenium could injure rice plant, causing lower biomass, especially in the roots. The supply of selenite could enhance the selenium contents of rice shoots and roots in solution culture and in soil culture. The selenium concentrations in roots were much higher than those in shoots supplied with the same rates of selenium and phosphorus. The interaction between selenium and phosphorus was evident. When the phosphorus supply increased to meet the needs of plant growth, phosphorus could promote absorption and accumulation of selenium in the shoots. If the phosphorus supply was excessive, phosphorus could inhibit the accumulation of selenium in the shoots at the lower selenite level (2 micromol l(-1)), but could not at the higher selenite level (10 micromol l(-1)). With the supply of phosphate increased, the selenium concentrations in the roots decreased significantly at both selenite levels. The presence of phosphate could decrease Se sorption on the soil surface and increase the selenium concentration in the soil solution. The concentrations of selenium in shoots and roots supplied with 0.08 g kg(-1) phosphorus were lower than those with no phosphorus supplied. With the increase of phosphorus added to 0.4 g kg(-1), the selenium concentration in shoots and roots increased. The effect of phosphorus on the concentration was statistically significant at all three selenium levels.     

Distribution of organo-chlorine pesticides (DDT and HCH) between plant and soil system

This paper reports a study of the distribution of organo-chlorine pesticides (DDT and HCH) between rice plants and the soil system by spraying before the heading stage at four different dosage levels--control, normal dosage (15 kg ha(-1) of 6% HCH and 7.5 kg ha(-1) of 25% DDT), double dosage and four times dosage. Soil and plant samples were taken respectively at the 1st h, 3rd, 10th, 20th, and 40th day after spraying and at the harvest time. The results indicate that less than 5% of HCH and 15% of DDT were absorbed by the surface of rice leaves for normal dosage. Most of both pesticides moved into the soil in solution after spraying. Compared with DDT, HCH was degraded and run off more easily. HCH residues in the surface soil layer (1-3 cm) were already below 6.4 microg kg(-1) at the mature stage, lower than Chinese Environmental Quality Standard for Agricultural Soils: HCH < 0.05 mg kg(-1). However DDT residues in the surface soil layer remained 172 microg kg(-1), higher than the national standard: DDT < 0.05 mg kg(-1). According to the test f OCP residues in rice seeds, it can be concluded that the OCP sprayed onto the surface of rice leaves can move into rice plants and accumulate in the seeds at the mature stage. HCH residues in rice seeds of the double and four times dosage treatments, and DDT residues in all treatments, exceeded the Chinese National Food Standard (HCH < 0.10 mg kg(-1), DDT < 0.20 mg kg(-1)).