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51.
Comprehensive field studies were initiated in 2002 to measure emissions of ammonia (NH3), hydrogen sulfide (H2S), carbon dioxide (CO2), methane (CH4), nonmethane hydrocarbons (NMHC), particulate matter <10 microm in diameter, and total suspended particulate from swine and poultry production buildings in the United States. This paper focuses on the quasicontinuous gas concentration measurement at multiple locations among paired barns in seven states. Documented principles, used in air pollution monitoring at industrial sources, were applied in developing quality assurance (QA) project plans for these studies. Air was sampled from multiple locations with each gas analyzed with one high quality commercial gas analyzer that was located in an environmentally controlled on-farm instrument shelter. A nominal 4 L/min gas sampling system was designed and constructed with Teflon wetted surfaces, bypass pumping, and sample line flow and pressure sensors. Three-way solenoids were used to automatically switch between multiple gas sampling lines with > or =10 min sampling intervals. Inside and outside gas sampling probes were between 10 and 115 m away from the analyzers. Analyzers used chemiluminescence, fluorescence, photoacoustic infrared, and photoionization detectors for NH3, H2S, CO2, CH4, and NMHC, respectively. Data were collected using personal computer-based data acquisition hardware and software. This paper discusses the methodology of gas concentration measurements and the unique challenges that livestock barns pose for achieving desired accuracy and precision, data representativeness, comparability and completeness, and instrument calibration and maintenance.  相似文献   
52.
Environmental Science and Pollution Research - With the acceleration of China’s urbanization process, construction activities have led to a substantial increase in construction waste....  相似文献   
53.
China is the world's largest energy consumer, and coal accounts for a higher proportion of the country's total energy consumption, yet during its 12th five-year plan (2011–2015), the coal share among total energy consumption significantly decreased. Previous studies exploring energy performance typically used energy consumption as an input, but this lacks the analytical capacity for the structure of energy consumption. Thus, this study splits energy input into two different inputs, coal consumption and non-coal energy consumption, and based on their differences with other variables, uses the hybrid dynamic data envelopment analysis model to assess the energy performance of China's provincial industrial sector during the period 2011 to 2015. We then compare coal consumption's and non-coal consumption's rooms for improvement and conclude that provinces in eastern and central China should reduce the amount of coal consumption, thereby improving energy performance. Conversely, provinces in the western region should target a balance between energy utilization efficiency and coal consumption.  相似文献   
54.
为了深入揭示安全生产水平同移动通信技术发展的内在联系,提出安全生产信息技术能力的概念及其监控管理连接、救援响应监测、定位导航追踪3方面子能力的定义,进而通过构建3方面子能力同移动通信主要性能指标之间的关系模型(SPITCMC),并对其进行深入分析和研究。研究结果表明:SPITCMC模型可以准确诠释过去移动通信技术发展对安全生产水平产生的影响,同时可用于预判未来移动通信技术发展对安全生产可能产生的影响程度,从而为后续相关工作的开展提供参考和借鉴。  相似文献   
55.
本文建立了准确预测多环芳烃(PAHs)及其烷基衍生物的正-辛醇/水分配系数(Kow)模型。模型表明PAHs的分配性质可用零阶价分子连接性指数(~°x~v)描述,~°x~v数值与PAHs的logKow成正比。应用本模型可以预测大范围PAHs的logKow值。  相似文献   
56.
Climate change: potential impact on plant diseases   总被引:1,自引:0,他引:1  
Global climate has changed since pre-industrial times. Atmospheric CO(2), a major greenhouse gas, has increased by nearly 30% and temperature has risen by 0.3 to 0.6 degrees C. The intergovernmental panel on climate change predicts that with the current emission scenario, global mean temperature would rise between 0.9 and 3.5 degrees C by the year 2100. There are, however, many uncertainties that influence these predictions. Despite the significance of weather on plant diseases, comprehensive analysis of how climate change will influence plant diseases that impact primary production in agricultural systems is presently unavailable. Evaluation of the limited literature in this area suggests that the most likely impact of climate change will be felt in three areas: in losses from plant diseases, in the efficacy of disease management strategies and in the geographical distribution of plant diseases. Climate change could have positive, negative or no impact on individual plant diseases. More research is needed to obtain base-line information on different disease systems. Most plant disease models use different climatic variables and operate at a different spatial and temporal scale than do the global climate models. Improvements in methodology are necessary to realistically assess disease impacts at a global scale.  相似文献   
57.
Lin YJ  Teng LS  Lee A  Chen YL 《Chemosphere》2004,55(6):879-884
The objective of this study was to investigate the effect of diethylamine and xenon simulated sunlight on the photodegradation of two forms of PCBs including PCBs in transformer oil and PCB congener 138. The result of GC chromatograms illustrated the shifting pattern of higher chlorinated biphenyls in transformer oil degraded to lower chlorinated biphenyls with the extension of exposure time. The effect of diethylamine and xenon simulated sunlight was significant on the photodegradation of both PCBs in transformer oil and congener 138. The initial degradation rates of congener 138 (1.14 x 10(-9) to 4.47 x 10(-9) mol l(-1) h(-1)) were in direct proportion to the initial concentrations of congener 138 which confirmed the pseudo-first-order reaction of PCB photodegradation. The apparent quantum yields (phi) of congener 138 using diethylamine in xenon photoreactor were ranged between 2.08 x 10(-2) and 9.8 x 10(-4). PCB congeners 123, 97, 70, 67, 33, 29, 17, 12, and 9 were detected as the descendants of the photodegradation of congener 138 through dechlorination. The major pathway of congener 138 photodegradation in this study was via para-dechlorination.  相似文献   
58.
Lin YJ  Lee A  Teng LS  Lin HT 《Chemosphere》2002,48(1):1-8
The objective of this study was to compare the effect of various experimental factors on the photoisomerization of nitrobenzaldehyde. The experimental factors included light source, light energy, exposure time, light path distance and the concentration of nitrobenzaldehyde. The results showed that the photoisomerization of nitrobenzaldehyde increased with increasing light exposure. Different light sources and light path distances demonstrated significant impact on the reaction rate constants and half-lives of nitrobenzaldehyde. Although the light energy of UV photoreactor was 47% lower than that of xenon photoreactor, quantum yield and UV/VIS absorption pattern confirmed the finding that the effect of ultraviolet photoreactor on nitrobenzaldehyde was similar to that of xenon photoreactor with the light path of 17 cm. It was caused by the shorter wavelength of UV photoreactor mainly on 254 nn. The product of nitrobenzaldehyde photoisomerization, nitrosobenzoic acid, was detected from samples after 5 or 10 min exposure of three light sources. The concentrations of nitrosobenzoic acid increased with the increasing of exposure time up to 20 or 60 min.  相似文献   
59.
氧化亚氮(N2O)是一种在大气中存留时间很长的强效温室气体,并被认为是21世纪破坏臭氧层的重要物质之一,气候预测需要对自然与人为排放的包括N2O在内的温室气体进行全面准确地估算.内陆水体是N2O的重要排放源,由于人为氮输入的增加,江河N2O的排放量可能逐年升高.本研究总结了江河N2O排放速率的研究方法,重点汇总了中国各气候带十大流域江河N2O的溶存浓度和水气界面交换通量,并与世界其他河流进行比较.结果表明我国江河溶存N2O浓度为0.3~1591 nmol·L-1,N2O释放通量为-12.2~2262.1 μmol·m-2·d-1,总体与世界其他江河的范围值具有可比性.在此基础上,进一步分析了江河N2O的产生和释放机理,探讨了水中溶解性无机氮、溶解氧、有机碳以及水文、地形地貌与气象条件等对江河N2O产生和释放的影响,并讨论了变化环境下江河N2O的排放特征.  相似文献   
60.
在两性修饰剂十二烷基二甲基甜菜碱(BS-12)和阳离子型表面修饰剂十六烷基三甲基溴化铵(CTMAB)复配修饰膨润土吸附苯酚最佳修饰比例的基础上,通过添加膨润土改变2种黄棕壤中的蒙脱石含量(分别为6%和43%),利用X射线衍射和有机碳含量表征了蒙脱石含量对BS+CTMAB复配修饰黄棕壤性质的影响.同时,采用批处理法研究了蒙脱石含量对BS-12+CTMAB复配修饰黄棕壤吸附苯酚能力的影响,对比了不同温度、p H和离子强度下吸附的差异,并探讨了影响机制.结果表明,CTMAB复配修饰增加了BS-12修饰土样的TOC含量并增强了土样对苯酚的吸附能力,且苯酚在复配修饰土中的解吸程度均高于CK、BS-12和CTMAB修饰土;随着黄棕壤中蒙脱石含量的增大,BS-12、CTMAB修饰和BS-12+CTMAB复配修饰土蒙脱石层间距、TOC含量和对苯酚吸附能力整体上均呈增加趋势;单因素对各修饰土样吸附苯酚的影响程度上,温度、p H逐渐减小,离子强度逐渐增大;蒙脱石含量决定的TOC是影响修饰土样对苯酚吸附能力大小的关键因素,修饰土样对苯酚的吸附依然以分配作用为主.  相似文献   
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