煤矸石堆场Fe、Mn迁移累积效应研究

通过对贵州织金典型煤矿区矸石堆场周边地表水体及耕地进行调查与采样分析,探讨了煤矸石堆场Fe、Mn元素迁移对周边地表水体及耕地累积效应的影响。研究结果表明:受煤矸石堆场酸性排水的影响,煤矸石堆场周边溪沟水Fe、Mn含量分别达0.81~32.14mg/L、1.17~8.42mg/L,超过"集中式生活饮用水地表水源地标准"限值的3~107、12~84倍。堆场周边旱作土中Fe、Mn含量分别达63 530~85 990mg/kg、243.1~910.1mg/kg,水稻土达46 940~75 810mg/kg、144.5~409.1mg/kg,Fe、Mn累积指数旱作土分别达1.61、2.97,水稻土分别达1.24、1.33。随着与堆场距离的增大,水稻土Fe、Mn含量逐步降低,在500m范围内Fe降低了35%,Mn降低了61%,而旱作土变化规律不明显。     

高蛋白有机废弃物厌氧消化系统稳定性及其耐氨氮机制解析

病死及自然灾害产生的大量畜禽尸体的不恰当处理处置会带来较为严重的环境卫生和公众安全隐患.本研究利用厌氧消化技术对畜禽尸体这类高蛋白有机废弃物的无害化处理进行尝试,旨在探索其适宜的有机负荷条件、系统的稳定性及潜在的氨抑制风险.研究表明高蛋白有机废物(以猪肉作为实验样品)作为厌氧消化基质时,系统稳定运行的有机负荷能够达倒(4.76±0.41)kg·m~(-3)·d~(-1);同时,VS降解率、单位体积沼气产率、单位添加VS沼气产率、单位降解VS沼气产率以及甲烷含量分别能达到95%、(3.72±0.21)L·L~(-1)·d~(-1)、(0.78±0.02)m~3·kg~(-1)、(0.82±0.02)m~3·kg~(-1)以及65%.在该条件下,TAN和FAN的浓度与系统产气性能没有直接线性关系,且在浓度高达5700 mg·L~(-1)和700 mg·L~(-1)时未呈现对系统的明显抑制作用.454高通量焦磷酸测序法对系统内古菌种群相对密度的分析结果表明,系统中氨抑制问题得到一定程度的缓解或者消除的原因可能为甲烷八叠球菌属(Methanosarcina)的优势地位并未受到明显影响,以及整个产甲烷菌种群在系统运行过程所得到的明显驯化.     

模拟状态下高尔夫球场果岭区域土壤氮磷浸出物对铁岗水库水质影响研究

通过采集高尔夫球场即将淹没的果岭土壤进行实验室条件下的模拟库基样品试验,对水库扩容后蓄水初期水质的变化情况进行了研究.结果表明:库水所含主要成分pH、高锰酸钾盐指数、总氮、总磷、氨氮和硝酸盐氮分别为7.4(mg/L)、30.8(mg/L)、1.16(mg/L)、1.189(mg/L)、0.21(mg/L)和0.11(mg/L);果岭20 cm土层库基土样pH、有机质、硝酸盐氮、氨态氮和有效磷分别为6.41(mg/kg)、10.29(mg/kg)、25.48(mg/kg)、25.76(mg/kg)和140.77(mg/kg).现有库基成分会改变库水高锰酸钾盐指标的升高.库水本身的总磷和总氮含量就严重超标.果岭库基本身的磷氮含量也很高.浸泡后果岭库基土样对降低浸出物总磷的严重超标起到了对冲的作用,致使总磷含量大为降低.     

Southwestern Intermittent and Ephemeral Stream Connectivity

Ephemeral and intermittent streams are abundant in the arid and semiarid landscapes of the Western and Southwestern United States (U.S.). Connectivity of ephemeral and intermittent streams to the relatively few perennial reaches through runoff is a major driver of the ecohydrology of the region. These streams supply water, sediment, nutrients, and biota to downstream reaches and rivers. In addition, they provide runoff to recharge alluvial and regional groundwater aquifers that support baseflow in perennial mainstem stream reaches over extended periods when little or no precipitation occurs. Episodic runoff, as well as groundwater inflow to surface water in streams support limited naturally occurring riparian communities. This paper provides an overview and comprehensive examination of factors affecting the hydrologic, chemical, and ecological connectivity of ephemeral and intermittent streams on perennial or intermittent rivers in the arid and semiarid Southwestern U.S. Connectivity as influenced and moderated through the physical landscape, climate, and human impacts to downstream waters or rivers is presented first at the broader Southwestern scale, and secondly drawing on a specific and more detailed example of the San Pedro Basin due to its history of extensive observations and research in the basin. A wide array of evidence clearly illustrates hydrologic, chemical, and ecological connectivity of ephemeral and intermittent streams throughout stream networks.     

A Water Allocation Decision‐Support Model and Tool for Predictions in Ungauged Basins in Northeast British Columbia,Canada

Pressures on water resources due to changing climate, increasing demands, and enhanced recognition of environmental flow needs result in the need for hydrology information to support informed water allocation decisions. However, the absence of hydrometric measurements and limited access to hydrology information in many areas impairs water allocation decision‐making. This paper describes a water balance‐based modeling approach and an innovative web‐based decision‐support hydrology tool developed to address this need. Using high‐resolution climate, vegetation, and watershed data, a simple gridded water balance model, adjusted to account for locational variability, was developed and calibrated against gauged watersheds, to model mean annual runoff. Mean monthly runoff was modeled empirically, using multivariate regression. The modeled annual runoff results are within 20% of the observed mean annual discharge for 78% of the calibration watersheds, with a mean absolute error of 16%. Modeled monthly runoff corresponds well to observed monthly runoff, with a median Nash–Sutcliffe statistic of 0.92 and a median Spearman rank correlation statistic of 0.98. Monthly and annual flow estimates produced from the model are incorporated into a map‐ and watershed‐based decision‐support system referred to as the Northeast Water Tool, to provide critical information to decision makers and others on natural water supply, existing allocations, and the needs of the environment.     

An investigation of double-glass-covered trapezoidal salt-gradient solar pond coupled with reflector

In the present study, a trapezoidal salt-gradient solar pond (TSGSP) has been investigated experimentally. The top surface of solar pond has been covered with double-glass cover in order to reduce the evaporative and convective losses from the top. This results in increase of temperature even in the top zone of the solar pond and leads to more volume utilization for heat storage in the pond. A reflector made of aluminium sheet has been used to enhance the solar intensity on the solar pond during sunny hours. A procedure, to determine optimum tilt angle of reflector in order to utilize maximum amount of solar energy at noon, has been proposed. The use of reflector enhanced the average solar intensity on the top surface of solar pond by 22%. The maximum average temperature of trapezoidal solar pond with glass cover and reflector has been observed to be 70.5°C. The thermal efficiencies of LCZ, NCZ and UCZ for the trapezoidal solar pond with double-glass cover and reflector have been estimated to be 32.73%, 23.22% and 5.30%, respectively. In addition to experimental investigation, the sunny area ratio of TSGSP has been theoretically computed and compared with the cuboid solar pond having same top surface area and depth in order to see the effect of pond shape on sunny area ratio. The average yearly sunny area ratio of trapezoidal solar pond has been determined to be 11% higher than that of cuboid one.     

陕南农村冬季PM_(2.5)主要化学组分特征

通过对陕南农村冬季PM_(2.5)采样分析,获得PM_(2.5)质量浓度及主要化学组分特征。PM_(2.5)平均质量浓度为89.5±42.0μg·m~(-3),超过国家二级标准。观测期间PM_(2.5)中OC、EC浓度平均值分别为16.0±6.9μg·m~(-3)和5.7±3.2μg·m~(-3),OC/EC平均比值为3.0±0.4。主要水溶性离子组分为NO_3~-、SO_4~(2-)和NH_4~+。粒子数浓度与表面积浓度峰值主要集中在0.5μm以下粒径段。PAHs、BeP和BaP平均质量浓度分别为48.9±10.9 ng·m~(-3)、3.0±0.9 ng·m~(-3)和1.2±0.7 ng·m~(-3),PAHs污染较严重,强致癌物BaP浓度超过国家环境空气质量标准年平均浓度限值。当地农村以石煤为主的能源结构及采用的燃烧方式是导致污染的重要因素。     

武汉地区基坑一般黏性土的力学特性与其物理指标间的相关性研究

一般黏性土作为武汉地区基坑工程中常见土层,对其工程特性与其物理力学参数的相关性研究对提高深基坑支护技术和经济性具有重要的现实意义。为研究武汉地区基坑工程典型一般黏性土的物理力学特性,以武汉地区45个基坑工程为基础,采用数理统计及回归分析方法,分析了武汉地区一般黏性土的工程特性与其物理力学参数间的相关关系。结果表明:武汉地区基坑工程一般黏性土的静力触探指标PS值变化范围为0.8~1.6 MPa,标准贯入指标N值的变化范围为3~7,土体饱和度较高,可塑及压缩性中等偏高,这将对基坑及高层建筑沉降变形产生不利影响;此外,一般黏性土的含水率、孔隙比、液限系数与直剪试验条件下抗剪强度指标c、值间呈负相关关系,一般黏性土的压缩模量与直剪试验条件下抗剪强度指标c、值间呈正相关关系。该研究结果可为武汉地区基坑工程设计的参数取值提供依据。     

难熔金属表面高温防护涂层研究进展与技术展望

回顾了难熔金属五大高温防护涂层体系的发展现状,即生成保护性氧化膜的金属间化合物涂层、贵金属涂层、生成保护性氧化膜的合金涂层、惰性氧化物陶瓷涂层以及玻璃陶瓷基复合涂层,总结了这些涂层的高温防护机理、制备方法以及失效机制。基于单一的传统高温防护涂层体系已经难以满足新一代高比冲姿、轨控火箭发动机以及高超声速飞行器热端部件对高温防护涂层提出的抗超高温氧化性能、优良的抗热震性能、良好的抗热冲刷(烧蚀)性能以及长服役寿命等性能需求的现状,简要介绍了过渡族金属的硼化物、碳化物等几种潜在的新型高温防护涂层材料体系,以及相应的涂层制备方法,这些新型涂层体系的发展有望满足现代宇航工业难熔金属热端部件的高温防护需求。     

厌氧发酵产沼气过程中脱氢酶活性检测工艺及其优化

为了优化脱氢酶活性这一指标在厌氧发酵产沼气系统中的检测方法,分别以小麦秸秆、羊粪及其混合原料(质量比1∶1)为发酵底物,通过Box-Behnken试验及响应面分析法确定并优化了沼气发酵系统中碘硝基四唑紫法脱氢酶活性的检测工艺,并对脱氢酶活性与甲烷产量进行了相关性分析.结果表明,3种底物均以乙醇作为萃取剂,以甲醛作为终止剂时显色效果最好.分别以秸秆、粪便及其混合为发酵底物时,脱氢酶检测在pH值分别为6.5、7.2、7.7,反应温度均在37℃下,碘硝基四唑紫质量分数均为0.15%,反应时间均为50 min时比色效果最好.相关性分析显示,厌氧发酵产沼气系统中脱氢酶活性与甲烷产量相关性显著.