Improvement of the assimilable organic carbon (AOC) analytical method for reclaimed water

Microbial growth is an issue of concern that may cause hygienic and aesthetic problems during the transportation and usage of reclaimed water. Assimilable organic carbon (AOC) is an important parameter which determines the heterotrophic bacterial growth potential of water. Pseudomonas fluorescens P17 and Spirillum sp. NOX are widely used to measure AOC in drinking water. The AOC values of various reclaimed water samples determined by P17 and NOX were compared with those determined by the new strains isolated from reclaimed water in this study. It showed that the conventional test strains were not suitable for AOC measurement of reclaimed water in certain cases. In addition to P17 and NOX, Stenotrophomonas sp. ZJ2, Pseudomonas saponiphila G3 and Enterobacter sp. G6, were selected as test strains for AOC measurement of reclaimed water. Key aspects of the bioassay including inoculum cell density, incubation temperature, incubation time and the pH of samples were evaluated for the newly selected test strains. Higher inoculum density (10⁴ CFU·mL^-1) and higher incubation temperature (25°C) could reduce the time required for the tests. The AOC results of various collected samples showed the advantages of the method proposed based on those five strains in evaluating the biologic stability of reclaimed water.     

Re-evaluation and re-classification of erionite series minerals

Governments and industries have introduced regulatory measures requiring safety controls to limit asbestos exposure of the general public and asbestos workers. Although erionite is a more potent health hazard mineral than asbestos, it has received far less attention. Precise definition of erionite, types of these fibrous minerals, and most importantly, characterization requirements still raise questions and often lead to arguments and even legal disputes. Many bulk erionite samples used in animal and cell experiments for carcinogenicity are not mineralogically pure. To test this hypothesis, we characterized two erionite standards from Rome, Oregon, and Pine Valley, Nevada, USA. These standards were characterized quantitatively using modern analytical techniques, and one of them, the erionite standard from Rome, Oregon, passed the required tests for positive identification, but the other, the erionite standard from Pine Valley, Nevada, did not. Furthermore, we observed ambiguous definitions, incorrect identifications, and inaccurate reporting of clinical investigations. To address this problem, we established characterization guidelines for positive identification of erionite using a modified balance error formula, and we re-evaluated and re-classified published erionite data from the literature as erionite-Ca, erionite-Na, and erionite-K. If data did not pass either the E% or Mg-content test, then we propose that reference to them in the literature be disregarded. Erionite requires special attention from the mineralogical community to help establish its true carcinogenetic properties. We believe that the characterization guidelines established in this paper will contribute to setting up rules and regulations for evaluation of erionite by regulatory agencies.     

动态浸出模拟实验系统与静态浸出试验的对比

建立了动态浸出试验－－小柱模拟实验系统,研究在非饱和水条件下危险物质在填埋场中的迁移和浸出规律,并和静肪浸出实验进行比较,结果表明,在非饱和入渗条件下危险物质的浸出浓度要比静态浸出实验的结果小１００倍左右,危险发的浸出速率也远小于静实验的结果,同时,危险物质的浸出速率随废物层饮水度的增加而迅速增加。     

2297-T87铝锂合金用于大气腐蚀性的比较

目的利用铝锂合金的大气腐蚀试验结果评价大气腐蚀性。方法对第三代铝锂合金2297-T87在6个自然环境试验站户外暴露后的腐蚀质量损失、腐蚀速率、腐蚀深度、拉伸性能进行分析,综合评价各地区大气腐蚀性。结果2297-T87铝锂合金在团岛、万宁、永兴岛暴露1年后出现显著腐蚀,腐蚀质量损失和腐蚀速率约为江津的2倍、西双版纳的4倍,北京的腐蚀质量损失和腐蚀速率最低。合金最大腐蚀深度的变化趋势与腐蚀质量损失和腐蚀速率的变化趋势一致。观察横截面发现,在万宁、永兴岛、江津暴露后,合金发生严重的点蚀,在腐蚀产物覆盖区域下方形成不规则蚀坑,而在团岛暴露后,合金内部发生晶间腐蚀。合金在江津、永兴岛、万宁、团岛暴露后的拉伸性能仍比较接近,且拉伸强度保持率在90%以上。结论将2297-T87铝锂合金暴露1年后的腐蚀质量损失、腐蚀速率、腐蚀深度作为表征指标,获得各试验站的大气腐蚀性顺序为:北京<西双版纳<江津<永兴岛<万宁<团岛。     

7A04铝合金在周浸试验中的腐蚀行为研究

采用周期浸泡的腐蚀试验方法,并通过电化学阻抗谱(EIS)、扫描电子显微镜(SEM)等检测技术,研究了7A04铝合金的腐蚀行为和腐蚀机理.结果表明,7A04铝合金的腐蚀动力学符合幂函数规律,其腐蚀历程为由点蚀经短暂的晶间腐蚀后快速发展为剥蚀,EIS由高中频3个容抗弧和低频收缩的感抗弧组成.     

大吨位起重机载荷试验的解决方案

本文介绍了国内外试重水袋的发展现状和水袋的结构组成,从试重水袋的安全、经济、节能、环保、高精度等优势进行了论述。提出了大型起重机载荷试验的解决方案,即水袋载荷试验法。     

树脂锚杆锚固长度声波探测技术及数值试验

针对煤岩巷道锚杆支护锚固失效引起的冒顶问题,建立了煤岩巷道顶板锚杆树脂锚固模型,采用数值模拟的方法对不同锚固方式下树脂锚杆的波导特性进行研究,得到了不同锚固长度与树脂锚杆激振响应特性曲线。通过对比分析,研究得出无论何种锚固方式,检测结果与实际锚固长度的误差大约在1%-6%,同时可采用修正补偿的方法降低检测误差。研究结果得出:采用应力反射波法检测树脂锚杆的锚固长度是一种行之有效的无损检测方法,可实现树脂锚杆锚固长度的便携、准确检测提供技术支持。     

生物炭基缓释肥的制备及其对土壤理化性质的影响

通过淋溶试验分析生物炭热解温度、生物炭与尿素比例、粘结剂含量对生物炭基缓释肥缓释性能的影响,采用土壤培育试验研究生物炭基缓释肥对土壤理化性质的影响。结果表明,600 ℃下热解而成的生物炭缓释性能优于300 ℃下热解形成的生物炭;生物炭添加比例和粘结剂含量的增加能提升生物炭基缓释肥的缓释性能;生物炭基缓释肥的加入可降低培育土壤的容重,增大土壤的饱和导水率,提高土壤pH值和土壤有机质含量。     

雷达吸波复合材料外观失效机理分析及控制方法研究

目的 解决多层泡沫夹芯结构的雷达吸波复合材料在环境效应下产生外观失效的问题。方法 制备3种类型的雷达吸波复合材料,开展典型自然环境试验。观察试验样品外观状态,并检测变形量。通过观察泡沫的微观组织形貌,检测热膨胀量变化及泡沫与树脂间的粘黏强度,用气相色谱质谱联用仪GCMS检测复合材料裂解气体成分,分析复合材料外观失效成因,并提出解决技术途径。结果 6个月自然环境试验后,1#、2#样品外观失效,而3#样品无明显变化。复合材料100℃裂解气体成分为氮气、二氯一氟乙烷、甲基膦酸二甲脂。4种泡沫在22～85℃的最大热膨胀量分别为–0.18%、–0.37%、–0.30%、–0.45%。环氧树脂与4种泡沫的粘黏强度在41～52N,而聚氨酯树脂达到了54～81N。结论 雷达吸波复合材料泡孔内残留气体的释放,是导致外观失效的根本原因。通过热处理工艺,减少样品残留气体量,并提升胶黏剂与泡沫的粘黏复合强度,是提升复合材料环境适应性的有效技术途径。     

非电力驱动多用途系列喷射式吸风器研制与应用

给出喷射式吸风器的结构及其工作原理;介绍了喷射器的性能与特点;笔者运用喷射器在大型化肥塔类设备内外施焊、等离子切割、球罐喷砂、箱式电炉模壳焙烧及马达线圈高温浸漆等10个不同施工场所进行了实际应用和验证,结果表明,该系列吸风器通风换气或排烟、排尘、排毒等性能安全可靠,且使用效果良好;同时,进一步研讨了改进和完善喷射式吸风器的有关技术问题。