Identification of potential electrotrophic microbial community in paddy soils by enrichment of microbial electrolysis cell biocathodes

Electrotrophs are microbes that can receive electrons directly from cathode in a microbial electrolysis cell (MEC). They not only participate in organic biosynthesis, but also be crucial in cathode-based bioremediation. However, little is known about the electrotrophic community in paddy soils. Here, the putative electrotrophs were enriched by cathodes of MECs constructed from five paddy soils with various properties using bicarbonate as an electron acceptor, and identified by 16S rRNA-gene based Illumina sequencing. The electrons were gradually consumed on the cathodes, and 25%–45% of which were recovered to reduce bicarbonate to acetic acid during MEC operation. Firmicutes was the dominant bacterial phylum on the cathodes, and Bacillus genus within this phylum was greatly enriched and was the most abundant population among the detected putative electrotrophs for almost all soils. Furthermore, several other members of Firmicutes and Proteobacteria may also participate in electrotrophic process in different soils. Soil pH, amorphous iron and electrical conductivity significantly influenced the putative electrotrophic bacterial community, which explained about 33.5% of the community structural variation. This study provides a basis for understanding the microbial diversity of putative electrotrophs in paddy soils, and highlights the importance of soil properties in shaping the community of putative electrotrophs.     

Removal and desorption of chromium in synthetic effluent by a mixed culture in a bioreactor with a magnetic field

Two chromium removal experiments were performed in bioreactors with and without a magnetic field under the same conditions.The release of the chromium present in the biomass was tested in two experiments one with the initial pH of the medium and one with pH 4.0.The objective was to remove Cr(Ⅵ) and total Cr from the effluent,this was carried out by placing biological treatments of synthetic effluent contaminated with 100 mg/L of Cr(Ⅵ) in a bioreactor with neodymium magnets that applied a magnetic field(intensity85.4 mT) to the mixed culture.The removal of Cr(Ⅵ) was approximately 100.0% for the bioreactor with a magnetic field and 93,3% for the bioreactor without a magnetic field for9 hr of recirculation of the synthetic effluent by the bioreactor.The removal of total Cr was61.6% and 48.4%,with and without a magnetic field,respectively;for 24 hr.The desorption of Cr(VI) in the synthetic effluent was 0.05 mg/L,which is below the limit established by Brazilian legislation(0.1 mg/L) for the discharge of effluent containing Cr(Ⅵ) into bodies of water.The results obtained for the removal of chromium in synthetic effluent suggested that there was no significant influence on the viable cell count of the mixed culture.The desorption of Cr(Ⅵ) in synthetic effluent after bioadsorption of chromium by the mixed culture in the process of removal of chromium in bioreactors with and without a magnetic field was not significant in either of the experiments with different initial pHs.     

双区静电除尘器的数值模拟研究

采用数模拟的方法研究了双区静电除尘器内流场分布、颗粒荷电及颗粒运动等难以直接测量的物理过程,构建了双区静电除尘过程完整的数值模型.采用泊松方程、电流连续性方程和匀强电场方程描述电场,采用N-S方程和雷诺应力标准湍流模型描述流场,采用拉格朗日法描述颗粒运动轨迹.通过截面风速与颗粒去除率的模拟值与实验值的对比,验证了数值模型在模拟内部流场和颗粒运动时的准确性.数值模拟结果表明：双区静电除尘器内部流场分布对入口风速的变化非常敏感;颗粒荷电方式占比由颗粒粒径决定;荷电区内颗粒向极板的趋近过程由流体曳力和电场力共同完成,收尘区内的趋近过程则由电场力主导;入口流速通过改变颗粒前进速度和内部流场形态来影响颗粒运动轨迹.     

基于 GJB 150.26 的军用装备流体污染试验实施方法

从适用性、参数选取、试验程序等角度深度梳理GJB 150.26试验标准,并研究流体污染试验程序的实施方法。通过对流体污染试验的研究背景和应用需求、相关标准应用现状和试验适用范围进行说明介绍,围绕基于GJB 150.26的流体污染试验参数选取原则、试验程序制定方法,探究符合标准架构的试验实施流程体系。按照所归纳研究整理的试验实施流程体系,结合工程实例对某型机载产品基于GJB 150.26的试验标准,针对其实际使用情况和相关技术协议文件制定了流体污染试验程序,进行了试验实施验证。流体污染试验实施目前在我国环境适应性工程领域缺乏理论基础指导,具备较大的开拓空间,通过对其实施方法和程序的研究能够有效地提升军用装备开展特种环境试验的技术能力。     

Selecting Socio-Economic Metrics for Watershed Management

The selection of social and economic metrics to document baseline conditions and analyze the dynamic relationships between ecosystems and human communities are important decisions for scientists, managers, and watershed citizens. A large variety of social and economic data is available but these have limited use without theoretical frameworks. In this paper, several frameworks for reviewing social-ecosystem relations are offered, namely social sanctions, sense of place, civic structure, and cultural differences. Underlying all of these frameworks are attitudes, beliefs, values, and norms that affect which questions are asked and which indicators are chosen. Much work and significant challenges remain in developing a standard set of spatially based socio-economic metrics for watershed management.     

Y5复合产絮菌及其产絮物絮凝特性试验研究

从含大量微生物菌群的土壤中筛选出了具有产絮效果的Y5菌液。比较不同培养条件下Y5菌液的絮凝率得出 :菌液絮凝性能是其中 3种复合菌株共同作用的结果 ;培养基初始pH值在 5 .0～ 9.0的范围内时 ,Y5菌液的生长量及其上清液的絮凝率都较高。     

用好防灾科技学院教育平台创建和弘扬防震减灾文化-恭贺母校升本暨校庆30周年

本文对防震减灾文化的组成、创建动力及其方法进行了探讨.初次提出了防震减灾文化的概念,并对创建防震减灾文化的目的和如何创建、弘扬防震减灾文化提出了看法和观点.     

用好防灾科技学院教育平台 创建和弘扬防震减灾文化——恭贺母校升本暨校庆30周年

本文对防震减灾文化的组成、创建动力及其方法进行了探讨。初次提出了防震减灾文化的概念，并对创建防震减灾文化的目的和如何创建、弘扬防震减灾文化提出了看法和观点。     

国产防锈水对威斯塔大鼠致癌性研究

对使用国产防锈水(主要成分为亚硝酸钠和三乙醇胺)的一个工厂进行肿瘤流行病学调查,发现该厂人员恶性肿瘤发病率略有增加。经长期给大白鼠饮用防锈水实验证明,该法可导致大鼠胰腺腺泡增生和不典型增生并能诱发出对照动物所没有的胰腺癌,同时还可引起胃粘膜的增生和胃乳头状瘤。     

花岗岩类岩体与金矿床成因关系的探讨

花岗岩类岩体与金矿床存在着密切的空间联系，其成因关系一直是矿床学界争论的焦点，目前传统的岩浆热液成因观点仍居统治地位。随着地质资料的积累，高温高压实验技术，尤其是金矿床同位素定年技术的进展，传统观点受到了严峻挑战。成岩成矿的时代与时差、成矿流体的来源和成矿物质的来源等确定金矿床成因类型关键因素的综合研究表明，有密切空间关系的金矿床与花岗岩类岩体之间，在多数情况下两者并无直接的成因联系，金矿床不是岩浆热液成因，而是与大气降水或建造水有关的改造成矿作用的产物。