Photochemical oxidation and dispersion of gaseous sulfur compounds from natural and anthropogenic sources around a coastal location

The photochemical oxidation and dispersion of reduced sulfur compounds (RSCs: H₂S, CH₃SH, DMS, CS₂, and DMDS) emitted from anthropogenic (A) and natural (N) sources were evaluated based on a numerical modeling approach. The anthropogenic emission concentrations of RSCs were measured from several sampling sites at the Donghae landfill (D-LF) (i.e., source type A) in South Korea during a series of field campaigns (May through December 2004). The emissions of natural RSCs in a coastal study area near the D-LF (i.e., source type N) were estimated from sea surface DMS concentrations and transfer velocity during the same study period. These emission data were then used as input to the CALPUFF dispersion model, revised with 34 chemical reactions for RSCs. A significant fraction of sulfur dioxide (SO₂) was produced photochemically during the summer (about 34% of total SO₂ concentrations) followed by fall (21%), spring (15%), and winter (5%). Photochemical production of SO₂ was dominated by H₂S (about 55% of total contributions) and DMS (24%). The largest impact of RSCs from source type A on SO₂ concentrations occurred around the D-LF during summer. The total SO₂ concentrations produced from source type N around the D-LF during the summer (a mean SO₂ concentration of 7.4 ppbv) were significantly higher than those (≤0.3 ppbv) during the other seasons. This may be because of the high RSC and SO₂ emissions and their photochemistry along with the wind convergence.     

建筑基坑(槽)土方坍塌的成因及预防措施

国内近年来在建筑施工中经常发生土方坍塌事故，给人民生命财产造成了巨大损失。为此我们必须认真分析事故原因，总结经验教训，采取有效改进措施，才能防止类似事故重复发生。     

Ag/Ag2SO3 plasmonic catalysts with high activity and stability for CO2 reduction with water vapor under visible light

Environmental Science and Pollution Research - The conversion of CO2 into useful raw materials for fuels and chemicals by solar energy is described using a plasmonic photocatalyst comprised of Ag...     

基于时差收敛算法的声发射源定位方法研究

本文针对传统基于时差的声发射定位方法精度及稳定性不足且易受检测环境影响的问题,提出了一种基于收敛算法的声发射源定位方法,经过循环迭代不断优化声发射信号的到达时刻计算方式,使得定位计算重构的定位源稳定收敛在近似同一区域,从而提高声发射源的定位准确度。     

Optimization of the food waste water incineration with respect to CO and NO<Subscript>x</Subscript> emission characteristics

The incineration of food waste water in conjunction with the domestic waste is getting attention as a food waste water treatment method, due to its low treatment cost and high efficiency. Many studies verified that the ammonia in the food waste water served as a reducing agent to suppress the generation of NO_x when the food waste water was injected and incinerated. However, they have not revealed the correlation between the change in the concentration of the CO and NO_x by the influence of the solid matters contained in the food waste water on the incineration of the wastes. The purpose of this study is to determine the optimum amount of the food waste water injected through four nozzles in the primary and secondary incineration chambers and to assess the correlation between the concentration of CO and NO_x in accordance with the food waste water injection in each chamber of the incinerator. For the study, four food waste water injection nozzles were installed; two (A and B) at the top of the primary incineration chamber and the other two (C and D) in the secondary incineration chamber. The correlation between the change in the concentration of CO and NO_x was studied adjusting the amount of the food waste water injected through the nozzles. From the result, Case II showed the concentration of CO and NO_x as 1.8–10 and 14–26 ppm, respectively, while Case I showed that of CO and NO_x as 15–30 and 9–18 ppm, respectively. Those levels are well below the Korean emission criteria, 50 ppm for CO and 80 ppm for NO_x. Based on the results, it is evident there is a certain trade-off between emission of CO and NO_x, and Case II which has relatively low concentration of CO is easier and cheaper to control.     

Ecological and economic impacts of green roofs and permeable pavements at the city level: the case of Corvallis,Oregon

A city's spatial footprint is covered by extensive impervious building roofs and paved surfaces, which contribute to greater storm-water runoff, more surface pollutants, and less carbon sequestration, hence, worse ecosystem services. This research conducts an empirical study on the ecological and economic impacts of a citywide adoption of green roofs and permeable pavements in Corvallis, OR. The effects on ecosystem services of using green roofs and pervious pavements for a low impact development are modelled using Integrated Value of Ecosystem Services Trade-offs and compared to those from the City's current conventional development without green roofs and pervious pavements. The differences are analysed for ecological impact by storm-water yield, storm-water purification, and carbon sequestration and economic impact by a cost-benefit comparison. The results indicate that low impact development, especially intensive green roofs on commercial/industrial buildings and permeable pavements for parking lots, plays a significant role, even with a higher initial implementation cost, for long-term urban sustainability.     

Possible particulate nitrite formation and its atmospheric implications inferred from the observations in Seoul,Korea

Simultaneous measurements of gaseous species and fine-mode, particulate inorganic components were performed at the University of Seoul, Seoul in Korea. In the simultaneous measurements, a certain level of nitrous acid (HONO) was observed in the gas-phase, indicating possible heterogeneous HONO production on the surface of the ambient aerosols. On the other hand, high particulate nitrite (NO^2?) concentrations of 1.41(±2.26) μg/m³ were also measured, which sometimes reached 18.54 μg/m³. In contrast, low HONO-to-NO₂ ratios of 0.007(±0.006) were observed in Seoul. This indicates that a significant fraction of HONO is dissolved in atmospheric aerosols. Around the Seoul site, sufficient alkalinity may have been provided to the atmospheric aerosols from the excessive presence of NH₃ in the gas-phase. Due to the alkaline particulate conditions (defined in this study as a particle pH >～3.29), the HONO molecules produced at the surface of the atmospheric aerosols appeared to have been converted into particulate nitrite, thereby preventing their further participation in the atmospheric O₃/NO_y/HO_x photochemical cycles. It was estimated that a minimum average of 65% of HONO was captured by alkaline, anthropogenic, urban particles in the Seoul measurements.     

Science, Power, and System Dynamics: the Political Economy of Conservation Biology

Abstract: Frustration with the lack of action on conservation issues by governments has sparked debate around the policy role of conservation biologists. We analyzed the political economy of conservation biology, that is, of the dynamics of the political and economic structures within which conservation biology operates, and we suggest more productive means for conservation biologists to achieve conservation goals. Within the modern state, conservation goals are marginalized because the growth needs of industrial capital have the highest priority. Environmental advocacy within this system largely addresses only proximate concerns and has limited success. Science is a product of modern society, but scientists now need to foster novel institutional arrangements in which humans can function within the limits of natural systems. This entails a larger recognition of the inherent contradictions residing within current institutions that themselves depend on unsustainably high resource flows. As one critical counterbalance to these institutions, we discuss community-based management and research as primary institutions through which sustainable use of natural resources might be achieved.     

A Comparison Study of Wheat Gluten Composites Filled with Dialdehyde Starch and Native Starch

Environmentally friendly green composites were prepared by blending Wheat gluten (WG) as matrix, dialdehyde starch (DAS) as filler and glycerol as plasticizer followed by compression molding of the mixture at 110 °C. The properties of the WG/DAS composite are compared with those of the WG/native wheat starch (NWS) composites. While tensile strength and strain at break decrease with increasing NWS content in the WG/NWS composites, a small content of DAS could improve tensile strength and strain at break simultaneously in the WG/DAS composites. The WG/DAS composites exhibit reduced moisture absorption in comparison with the WG/NEW composites. Formation of chemical bonding between DAS and WG is beneficial for the dispersion of DAS in the WG matrix and WG/DAS composites exhibit improved mechanical properties and reduced moisture absorption over the WG/NWS composites.     

转轮式洗轮机对车轮带泥的冲洗效果

施工车辆车轮带泥是我国道路扬尘污染控制面临的共性和突出问题。为在国内推广使用洗轮机提供技术依据，通过检测工地出口外道路积尘负荷来估算转轮式洗轮机对车轮带泥的冲洗效率，并以该洗轮机作为车轮带泥检测设备，检测和统计北京市车轮带泥量。结果表明，（1）转轮式洗轮机可以将工地出口外100m道路积尘负荷增量由64．4g／m2降至5．9g／m2，转轮式洗轮机对车轮带泥的冲洗效率大于90％；（2）渣土车和混凝土车车轮带泥量的平均值分别为5．1和2．2kg／车；（3）北京市未来车轮带泥量将超过8．8万t／a，施工车辆全部经过转轮式洗轮机冲洗后，车轮带泥量可削减7．9万t／a。建议在相关法律法规中以强制性条款落实施工车辆车轮带泥机械化冲洗要求。