湘江干流水环境质量演变特征及其关键因素定量识别

为科学有效地保护湘江流域水环境，定量识别湘江干流主要水质指标的驱动因素，该研究基于1990~2016年水质监测数据及沿岸永州 长沙五市社会经济发展指标，采用Mann-Kendall检验法分析湘江干流水环境演变趋势，通过逐步回归分析确定各地区各水质指标主要驱动因素。结果表明：湘江干流COD_Mn、Cd、As整体呈下降趋势，上游BOD₅呈下降趋势，上中游NH₃-N呈上升趋势，中游衡阳、株洲市重金属Cr⁶⁺呈上升趋势，衡阳市TP呈上升趋势，中下游BOD₅呈上升趋势；定量追溯各水质指标影响因素得出工业污染是湘江干流重金属As、Cr⁶⁺、Cd主要驱动因素，永衡株潭地区NH₃-N，衡阳市BOD₅、COD_Mn、TP及衡株潭地区BOD₅均以农业污染影响为主；发现产业结构调整对干流水环境有显著影响，建议在流域产业结构调整过程中加强转型升级。     

空调控温过程的系统动力学模拟分析

以房间、人员、设备和空调设备组成的空调控温系统为单元,以室温为目标,研究影响室温的各因素之间的关系,找出哪种因素是主要因素.运用Vensim软件建立空调控温系统的因果图和流图,并建立速率方程,进而进行模拟.根据模拟结果,对室温和温差进行分析,并探讨了空调调节系数、房子散热系数变动时对室温和波动时间的影响情况.验证了空调控温过程中室温的震荡过程和空调机发生作用的反应延迟时间.     

地震救灾过渡安置点避雷针的布设选点及安装要求

"5.12"汶川8级大地震波及范围很大,给陕西省部分地方造成了不小的损失.灾后,汉中、宝鸡的地震救灾过渡安置点由于缺乏防雷电保护,打雷时有遭受雷电灾害的可能,亟需要对其采取防雷电保护措施.对救灾过渡安置点采用独立避雷针进行防护,该措施安全可靠、简便易行,就成为首选,其布设选点要科学、规范,可使其效益最大化,避雷针的制作和安装应符合技术标准要求,做到牢固可靠,在施工中要因地制宜.综合考虑,始终把安全和牢靠放在首位.     

脆弱生态环境耦合下的贫困地区可持续发展研究

研究表明，中国贫困地区的分布与脆弱生态环境的分布存在一种地理空间意义上的耦合，这种耦合是一种非良性的耦合，存在着诸多问题并我着当地的社会经济发展，要改变这一现状，实现区域社会经济可持续发展，必须革新现有的贫困人口生存方式和社会经济发展模式，据此，本文提出了实现贫困地区社会经济可持续发展的战略措施应是依托现有的资源优势，推广生态农业技术，发展绿色食品和开展生态旅游。     

废水产氢产酸/同型产乙酸耦合产酸条件优化

为了更好地发挥产氢产酸/同型产乙酸耦合系统在废水厌氧发酵生产乙酸方面的优势,有必要寻找一种简单有效的方法以获得该系统产酸的优化条件.利用经过加热处理并活化的厌氧污泥作种泥,以模拟废水中的葡萄糖为底物,针对发酵时间、底物浓度、种泥浓度、初始pH进行4因素10水平均匀设计实验,得到了乙酸生产指标与产酸条件之间关系的回归方程;也得到了以高乙酸产量为主要目标导向同时兼顾高乙酸产率和高乙酸生产强度目标的优化条件;优化条件实验乙酸浓度比均匀设计中最高乙酸浓度提高20%左右.研究表明,将均匀设计应用于废水产氢产酸/同型产乙酸耦合产酸条件优化,可以避免盲目性,迅速获得满意结果.     

氯苯嘧啶醇在水体中的光解机制研究

以太阳光为实验光源研究了氯苯嘧啶醇在水溶液中的光解,考察了pH、水体类型、溶解氧及卤素离子等对其光解的影响.结果表明,氯苯嘧啶醇在水溶液中的光解符合一级动力学方程,在不同水体中氯苯嘧啶醇光解的速率大小顺序为:重蒸水>水库水>湖水>池塘水;氯苯嘧啶醇光解的半衰期随着溶液pH的增大而延长,当pH为5、7、9、11时光解半衰期分别为5.00、6.86、7.45、7.53 h;3种卤素离子对氯苯嘧啶醇光解有很大的影响,均表现出强的猝灭作用,3种离子的猝灭能力的大小顺序为Ⅰ->Br->Cl-;溶解氧和三重态光猝灭剂山梨酸均对氯苯嘧啶醇在水中的光解没有影响,而三重态光敏剂丙酮则对其光解有较强的猝灭作用,表明氯苯嘧啶醇在水中的光解主要以直接光解为主,光解过程不经历三重态.     

Bioassay: A useful tool for evaluating reclaimed water safety

Wastewater reclamation and reuse has been proved to be an effective way to relieve the fresh water crisis. However, toxic contaminants remaining in reclaimed water could lead to potential risk for reuse, and the conventional water quality standards have difficulty guaranteeing the safety of reclaimed water. Bioassays can vividly reflect the integrated biological effects of multiple toxic substances in water as a whole, and could be a powerful tool for evaluating the safety of reclaimed water. Therefore, in this study, the advantages and disadvantages of using bioassays for evaluating the safety of reclaimed water were compared with those of conventional water quality standards. Although bioassays have been widely used to describe the toxic effects of reclaimed water and treatment efficiency of reclamation techniques, a single bioassay cannot reflect the complex toxicity of reclaimed water, and a battery of bioassays involving multiple biological effects or in vitro tests with specific toxicity mechanisms would be recommended. Furthermore, in order to evaluate the safety of reclaimed water based on bioassay results, various methods including potential toxicology, the toxicity unit classification system, and a potential eco-toxic effects probe are summarized as well. Especially, some integrated ranking methods based on a bioassay battery involving multiple toxicity effects are recommended as useful tools for evaluating the safety of reclaimed water, which will benefit the promotion and guarantee the rapid development of the reclamation and reuse of wastewater.     

Hygroscopicity measurement of sodium carbonate, β-alanine and internally mixed β-alanine/Na2CO3 particles by ATR-FTIR

Water-uptakes of pure sodium carbonate(Na_2CO_3),pure β-alanine and internally mixedβ-alanine/Na_2CO_3 aerosol particles with different mole ratios are first monitored using attenuated total reflectance Fourier transform infrared spectroscopy(ATR-FTIR) technique.For pure Na_2CO_3 aerosol particles,combining the absorptions at 877 and 1422 cm-1 with abrupt water loss shows the efflorescence relative humidity(ERH) of 62.9%–51.9%.Upon humidifying,solid Na_2CO_3 firstly absorbs water to from Na_2CO_3·H2 O crystal at 72.0% RH and then deliquesces at 84.5% RH(DRH).As for pure β-alanine particles,the crystallization takes place in the range of 42.4%–33.2% RH and becomes droplets at ～ 88.2% RH.When β-alanine is mixed with Na_2CO_3 at various mole ratios,it shows no efflorescence of Na_2CO_3 whenβ-alanine to Na_2CO_3 mole ratio(OIR) is 2:1.For 1:1 and 1:2 β-alanine/Na_2CO_3 aerosols,the ERHs of Na_2CO_3 are 51.8%–42.3% and 57.1%–42.3%,respectively.While β-alanine crystal appears from 62.7% RH for 2:1 and 59.4% RH for both 1:1 and 1:2 particles and lasts to driest state.On hydration,the DRH is 44.7%–75.2% for Na_2CO_3 with the OIR of 1:1 and 44.7%–69.0%for 1:2 mixture,and those of β-alanine are 74.8% for 2:1 mixture and 68.9% for two others.After the first dehumidification–humidification,all the water contents decrease despite of constituent fraction.And at ～ 92% RH,the remaining water contents are 92%,89% and 82%at ～ 92% RH,corresponding to OIR of 2:1,1:1 and 1:2 mixed system,respectively.     

Development of a static test apparatus for evaluating the performance of three PM2.5 separators commonly used in China

PM_(2.5) separator directly affects the accuracy of PM_(2.5) sampling.The specification testing and evaluation for PM_(2.5) separator is particularly important,especially under China's wide variation of terrain and climate.In this study,first a static test apparatus based on polydisperse aerosol was established and calibrated to evaluate the performance of the PM_(2.5) separators.A uniform mixing chamber was developed to make particles mix completely.The aerosol concentration relative standard deviations of three test points at the same horizontal chamber position were less than 0.57%,and the particle size distribution obeyed logarithmic normal distribution with an R~2 of 0.996.The flow rate deviation between the measurement and the set point flow rate agreed to within ± 1.0% in the range of -40 to 50℃.Secondly,the separation,flow and loading characteristics of three cyclone separators(VSCC-A,SCC-A and SCC112) were evaluated using this system.The results showed that the 50% cutoff sizes(D_(50)) of the three cyclones were 2.48,2.47 and 2.44 μm when worked at the manufacturer's recommended flow rates,respectively.The geometric standard deviation(GSD) of the capture efficiency of VSCCA was 1.23,showed a slightly sharper than SCC-A(GSD = 1.27),while the SCC112 did not meet the relevant indicator(GSD = 1.2 ± 0.1) with a GSD = 1.44.The flow rate and loading test had a great effect on D_(50),while the GSD remained almost the same as before.In addition,the maintenance frequency under different air pollution conditions of the cyclones was summarized according to the loading test.