Experimental and theoretical investigations for mitigating NaAlH4 reactivity risks during postulated accident scenarios involving exposure to air or water

Experimental and theoretical studies were conducted to investigate the pyrophoricity and water-reactivity risks associated with employing sodium alanate (NaAlH₄) complex metal hydride in on-board vehicular hydrogen (H₂) storage systems. The ignition and explosivity of NaAlH₄ upon exposure to oxidizers in air or water were attributed to the spontaneous formation of stable hydroperoxyl intermediates on the NaAlH₄ surface and/or H₂ production, as well as the large driving force for NaAlH₄ conversion to favorable hydroxide products predicted by atomic and thermodynamic modeling. The major products from NaAlH₄ exposure to air: NaAl(OH)₄, gibbsite and bayerite Al(OH)₃, and Na₂CO₃ observed by XRD, were identified to be formed by surface-controlled reactions. The reactivity risks were significantly minimized, without compromising de-/re-hydrogenation cyclability, by compacting NaAlH₄ powder into wafers to reduce the available surface area. These core findings are of significance to risk mitigation and H₂ safety code and standard development for the safe use of NaAlH₄ for on-board H₂ storage in light-duty vehicles.     

Status of air pollution in Beijing

A study has been made on elements organic constituents, TSP, SO2,NO2 of atmospheric pollutants in Beijing. 17 elements, and some PAHs, e. g. B(a)P, B(b, j, k)P, and B(g, h, i)P, in airborne particles by X-ray fluorescence spectroscopy and HPLC, GC/MS, have been determined respectively. It has been shown that the elements Pb, Zn, S and Cu were more enriched in fine particles and different valence states of sulfur at various sites. It was found that the concentrations of S6+ and S2-were more than 85% and less than 15% of the total sulfur respectively. Concentrations of major PAHs and sulfur-containing compounds increased in winter and in urban area. High values for Pb and Zn in city, Fe and Mn at industrial area and Cu, Al rural sites were obtained respectively. This implies the functions of different elemental sources of various sites. Thus, elements can be from distingushed anthropogenic and natural sources.The main contribution of SO2 was found of to have same seasonal variation as the anthropogenic el     

Petroleum hydrocarbon concentrations in eight mollusc species along Tamilnadu coast, Bay of Bengal, India

Eight mollusc species and sediment samples collected from three different stations along Tamilnadu coast, Bay of Bengal, India were analysed for the levels of petroleum hydrocarbons to elucidate the status of the petroleum residues in mollusc meant for human consumption. The concentrations of petroleum hydrocarbons in sediments along Tamilnadu coast varied from 5.04–25.5 g/g dw (dry weight). High concentration of petroleum hydrocarbons in the sediment of Uppanar estuary (25.5 1.45 g/g dw) was perhaps land and marine based anthropogenic sources of this region. The petroleum hydrocarbon residues in eight mollusc species collected from Uppanar, Vellar and Coleroon estuaries varied between 2.44–6.04 g/g ww (wet weight). Although the concentration of petroleum hydrocarbons in sediment of the Uppanar region was markedly higher than the background, the petroleum hydrocarbon residues in mollusc collected from Uppanar estuary did not suggest bioaccumulation. The results signified that industrial growth has affected the aquatic environments and regular monitoring will help to adopt stringent pollution control measures for better management of the aquatic region.     

空气污染与儿童呼吸系统患病率的相关分析

 在流行病学调查和空气污染物监测的基础上，研究讨论了儿童呼吸系统患病率与空气污染之间的相关关系，结果表明，空气中细颗粒物（PM_2.5）和可吸入颗粒物（PM₁₀）与儿童呼吸系统患病率呈线性正相关关系，其影响比SO₂、Nox更密切．哮喘明显受颗粒物、SO₂、Nox的综合作用的影响．未感冒咳嗽发生率明显受细颗粒物和Nox污染综合作用的影响．     

全球沙尘气溶胶源汇分布及其变化特征的模拟分析

根据全球沙尘气溶胶气候模式GEM-AQ/EC模拟的1995~2004年的沙尘起沙量和干湿沉降量,分析了沙尘气溶胶源汇的全球时空变化特征.全球沙尘起沙量集中在各个主要沙漠地区,北非对全球沙尘气溶胶贡献最大为66.6%.沙尘气溶胶沉降的高值区分布在沙漠源区及其紧临的下风地区.最大净沙尘气溶胶接收主要分布在沙漠周围地区并形成净接收量大于10t/(km2×a)的位于0°N~60°N之间的北非、欧亚大陆、西太平洋、北印度洋、北美和大西洋的带状分布.在北非、阿拉伯半岛、中亚、东亚和澳大利亚5个主要沙漠地区中,起沙量和沉降量都存在明显的季节变化,除中亚其他4个区域干湿沉降量和起沙的季节变化基本一致;东亚地区沙尘气溶胶起沙量和总沉降量的季节变化最为明显,而北非沙漠起沙量和总沉降量的季节变化最小,其他3个区域的季节变化幅度基本相同.中亚起沙峰值和阿拉伯半岛起沙次峰值出现在夏季,其他区域的峰值均出现在春季.10年间全球陆地年平均起沙量为(1500±94)Mt,保持略微上升趋势.以北非沙漠起沙量年际变化率最低(6.3%), 而以东亚(28.3%)和澳大利亚(45.0%)起沙量年际变化最为明显;全球陆地的沙尘气溶胶沉降量以约9.9Mt/a的速率递减,全球海洋的沙尘气溶胶沉降递增.     

Fuzzy AHP-based study of cleaner production implementation in Taiwan PWB manufacturer

In recent years, many electronic manufacturing firms have looked upon Cleaner Production (CP) as the means by which they could maintain environmental practice and competitive advantages. CP has been adopted by companies as an important factor in enhancing industrial productivity. Sustainable projects that deal appropriately with environmental and social factors are also more likely to be the most profitable.This paper investigated the criteria and attributes that determine a successful adoption and implementation of CP in reference to PWB manufacture in Taiwan. Fuzzy Analytic Hierarchy Process (FAHP) methodology is used to discuss the different decision criteria that include Organizing, Systems and Technologies, Measurement and Feedback, Working environment and Worker's Culture which are all vital factors in an effective CP implementation. AHP is an efficient tool in controlling the fuzziness of the data involved in choosing the most preferred decision variables. The linguistic level of comparisons produced by the manufacturers and experts are tapped and constructed in a form of triangular fuzzy numbers in order to construct fuzzy pairwise comparison matrices. The implementation of the system is demonstrated by a problem involving three stages of hierarchy which contains different criteria and attributes at a wider perspective within an environmental uncertainty. The findings advocate that these enterprises would need to setup the priorities of the CP implementation. The results suggest a generic hierarchical model of organizations of which the highest level is to be prioritized among the CP implementation factors.     

At a tipping point? How the debate on biofuel standards sparks innovative ideas for the general future of standardisation and certification schemes

Consumer demand for environmentally and socially responsible products is the driving force behind the expansion of competing certification systems. Paradoxically, this has led to an increasingly crowded marketplace for labels and confusion among stakeholders such as producers, retailers and buyers, rather than providing clear and reliable product information as intended. The situation has sparked a debate about the future of certification schemes and the need for a more streamlined system. This article explores some of the innovative ideas coming from the current discussion regarding biofuel certification and standardisation and outlines how those ideas can be applied to create a global generic standard-setting scheme for natural resources.     

Operational decisions in response to a performance-based regulation to reduce organic waste impacts near Atlantic salmon farms in British Columbia,Canada

Nutrient enrichment of the seafloor (benthos) has been a primary subject of investigation since the beginning of commercial salmon farming. Waste feed and feces passing through the containment nets can create zones of organic enrichment to the benthos in the vicinity of the pen cages. Early studies of salmon farming in British Columbia Canada (500–1200 metric ton production farms) showed that these effects varied greatly and were reduced where conditions of adequate water depth and strong tidal currents were present. More recent studies of farms producing in excess of 2000 tons of fish have documented measurable organic benthic impacts.The implementation of a performance-based waste regulation in British Columbia in 2002 has caused operational changes to achieve and maintain compliance. This paper describes field monitoring data for four representative farm operations including the waste impact levels prior to the implementation of regulatory standards and the effect of adaptive management actions taken to reduce organic enrichment such as modified feed delivery, relatively small position changes to the cages or reducing site production to achieve continuing compliance.Monitoring over several full production cycles at selected farms indicated that sediment impacts at maximum production levels have decreased while maintaining, and in some cases increasing overall production of salmon.     

A 50 MW concentrating solar power plant for Jordan

The potential of concentrating solar power plant (CSPP) technology in Jordan is assessed and the next steps for development of the first CSPP in the country are presented. For this purpose, a prototype of a 50 MW CSPP for electricity generation in Jordan is proposed and analysis of its economic feasibility has been performed. Moreover, a calculation model – using the concept design of the proposed CSPP, and the solar irradiation data – was developed to estimate the energy yield of the plant. Based on the analyzed solar irradiation data, it was found that Jordan has an outstanding potential for CSPP, especially in the southern locations of the country such as Quweira. At the same time Jordan's energy master plan is seeking for independent energy supply and for an increasing share of renewable energies. Furthermore, Jordan's demand curve over a day closely matches the electricity production of the proposed plant. Combination of these factors creates a very favorable situation. Therefore, establishment of the proposed 50 MW CSPP is highly recommended not only in Jordan, but also in many other countries, which have similar political and economical conditions such as those countries located in the Middle East and North Africa (MENA) region.     

Cleaner tanning practices for tannery pollution abatement: Role of enzymes in eco-friendly vegetable tanning

Concern about pollution related problems in the global scenario are persuading all the processing industries to adopt cleaner manufacturing practices. Thus, the leather industry is also under pressure to look for effective alternative tanning materials for chromium. Natural products like vegetable tannins are regaining importance. However, there are limitations in the use of vegetable tanning materials because of its high organic load in the effluent, which are difficult to degrade leading to high chemical oxygen demand (COD). Moreover, conventional vegetable tanning process requires partial pickling that involves the use of sodium chloride, to suppress osmotic swelling. This results in very high amount of total dissolved solid (TDS) content in wastewaters. In this investigation, an attempt has been made to design an eco-friendly vegetable tanning process combining pickle-free tanning and application of proteolytic enzymes to improve the exhaustion of vegetable tannins. Such an approach has resulted in more than 95% tannin exhaustion in the case of the experimental process, an increase of 10% compared with the conventional vegetable tanning process. The tanned leathers showed slight improvement in hydrothermal stability. Physical and tactile evaluation of experimental leathers has been better than conventionally tanned leathers. Surface colour values illustrated negligible variation in colour and shade between control and experimental leathers. The resultant leather showed opened up, split compact fibre structure that has been well coated, indicating that the enzyme assisted tanning process did not bring about any major change or destruction on the fibre structure of the leathers. The optimized system has been field tested in a commercial tannery. The results showed that the enzyme assisted tanning process is efficient in terms of improved quality of leather and also led to reduction in total solids (TS), chlorides and COD loads. The enzyme assisted tanning system presented appears to be a viable option for combating pollution arising from the conventional vegetable tanning system.