Small-scale fire performance assessment of intumescent coatings on metal tubes containing ammonium nitrate. A stepping-stone towards their application as a fire safety measure on road transportation tanks?

Ammonium nitrate is used in vast amounts globally, first and foremost as a component of fertilizers and explosive formulations. This usage necessitates its transportation which, as for most hazardous materials, involves certain risks. For oxidizing materials such as ammonium nitrate, the ultimate consequence of road transportation incidents is usually considered to be fire followed by explosion. Even though the probability in general is low, substantial reduction in its risk is a great gain for public safety. Thus, identifying novel and improving current safety measures for risk reduction, is an important aspect in the field of hazardous materials. Herein, a series of experiments are reported, which demonstrate the fire protection performance of two state-of-the-art intumescent passive fire protection materials on small-scale metal test tubes containing ammonium nitrate. Albeit being initial experiments on laboratory-scale, these results provide a promising starting point for further investigations on the potential of these materials for the fire protection of ammonium nitrate when carried in metal tanks. At its best, a prominent protection of ammonium nitrate from heat exposure was observed, as the temperature was kept well below its boiling point for more than 2.5 h. Successively, it resulted in a complete recovery of the sample material. This was in large contrast to the observed results for the unprotected test tubes, which led to complete decomposition of the sample after 11 min.     

工业大宗物资的铁路物流网络空间结构特征研究——以云南省为例

为提取工业大宗物资铁路物流网络特征,从物流网络流动格局、节点特征和运输轴线3个方面,基于社会网络分析与空间分析方法构建了考虑流入—流出双向性的工业大宗物资铁路物流网络特征分析体系,并以云南省为例,利用云南省工业大宗物资的铁路货运全OD数据透视该省煤、金矿、钢铁、石油、化工等5类工业大宗物资铁路物流网络的组织结构、空间运输联系、网络节点和主要通道。结果表明:云南省5类工业大宗物资物流网络组织均具有明显的小世界特性,网络整体呈现放射状,形成明显的集聚少核的空间分布格局,运输走向"廊道效应"显著。     

有机物料投入对喀斯特地区土壤磷素赋存形态与含phoD基因细菌群落的影响

针对喀斯特地区有机物料盈余、土壤养分贫瘠和易流失的特点,设置长期有机物料还田小区定位试验,试验包括6个处理：不施肥对照（CK）、无机肥（NPK）、无机肥+玉米秸秆（NPKS）、无机肥+农家肥（NPKM）、无机肥+滤泥（NPKL）和无机肥+甘蔗灰（NPKA）.研究不同有机物料投入对土壤磷赋存形态和磷活化功能微生物（含有机磷矿化基因细菌）群落结构的影响.通过3 a断续的观测,结果表明,土壤全磷（TP）、速效磷（Olsen-P）和二钙磷（Ca₂-P）含量呈逐年增加趋势,而氯化钙磷（CaCl₂-P）含量呈先降低再增加的趋势;与不施肥对照相比,有机物料投入尤其是滤泥配施能显著提高土壤全氮（TN）、TP、Olsen-P、CaCl₂-P和Ca₂-P含量,其次是甘蔗灰和农家肥配施处理;相关分析表明,CaCl₂-P、Ca₂-P和Olsen-P均与土壤交换性钙（Ca-ex）含量显著正相关;冗余分析（RDA）表明土壤TN、Ca-ex、有机碳（SOC）和土壤全钾（TK）含量是影响土壤磷组分的关键因子.高通量测序分析含有机磷矿化基因（含phoD基因）细菌群落结果表明,与不施肥对照相比,秸秆还田配施无机肥处理显著增加土壤含phoD基因细菌丰富度,但各处理间含phoD基因细菌群落结构无显著差异.RDA分析结果表明,土壤Ca-ex、TK、Olsen-P、pH和SOC是驱动含phoD基因细菌群落变化的关键因子.总体上看,无机肥配施滤泥、甘蔗灰和农家肥是广西喀斯特地区农田土壤较为合适的养分管理方式.研究可为喀斯特地区有机废弃资源利用与土壤磷素管理提供科学依据.     

作物秸秆材料处理养殖废水中氮的周年去除效果及其对氮循环微生物丰度的影响

基于前期研究,利用秸秆材料处理养殖废水,能够有效降低养殖废水中氮的浓度,但周年去除效果及其对氮循环微生物丰度的影响尚不清楚.设置麦秸、玉米秆、稻草和空白对照这4个处理,试验周期为1 a,研究秸秆材料处理养殖废水中氮的周年去除效果及其氮循环微生物功能基因丰度动态变化.结果表明：① 3种作物秸秆对养殖废水TN和NH₄⁺-N等主要污染物的去除效率均以前6个月为最佳,后6个月去除效率明显下降;稻草及麦秸对TN和NH₄⁺-N的周年去除效果较好,其中稻草和麦秸对TN去除率分别为（32.81±11.34）%和（32.99±9.60）%,对NH₄⁺-N去除率分别为（35.3±13.23）%和（34.97±12.00）%;②添加秸秆材料生物基质消纳系统中氮循环微生物功能基因nirK、nirS和hzsB基因丰度为6.45×10⁹、6.18×10⁹和2.31×10⁹copies·L^-1,AOA和AOB基因丰度分别为6.12×10¹⁰copies·L^-1和4.93×10⁹copies·L^-1;16S rRNA高达8.90×10¹⁰copies·L^-1,均显著高于空白处理（P<0.05）.其中添加稻草和麦秸处理中hzsB基因和nirS基因丰度相对较高,表明添加稻草和麦秸显著增强了生物基质消纳系统厌氧氨氧化和反硝化微生物作用.同时,相较于其他处理,添加麦秸增加了生物基质池AOA和AOB基因丰度,表明麦秸能够促进生物基质消纳系统的硝化作用.以上研究结果为秸秆材料处理养殖废水中氮去除分子机制提供了数据支撑.     

赶不上定理及其循环经济理论意义

阐释了在一个正常发展的长时期的宏观经济体系中人均物质消费量永远上升的观点,研究了人均GDP增长速度和物质利用强度变化速度之间的数量关系,根据二者变化速度相对快慢提出和证明了保证人均物质消费量上升的充分必要条件即赶不上定理.利用赶不上定理,论述了循环经济是解决人类经济增长的无限性与自然资源有限性之间的矛盾的根本途径,当人均GDP增长速度为零时进行结构调整必然降低人均物质消费量,引发社会不安定现象;当人均GDP增长速度足够快时,可以大幅度进行结构调整而不降低人均物质消费量.     

Radiation Crosslinking of Poly(Butylene Succinate) in the Presence of Inorganic Material and Its Biodegradability

Three kinds of poly(butylene succinate)s (PBS) with different molecular weight were irradiated with electron beams in the presence of inorganic material. Fourteen kinds of inorganic materials were used in this work. The presence of inorganic material inside cross-linked PBS samples enhances the yield of gel formation. The heat stabilities of PBS samples were checked; it was found that silicon dioxide and carbon black significantly improve these properties. Enzymatic and soil burial tests were performed; the presence of these inorganic materials in cross-linked PBS accelerates the rate of biodegradation.     

Life cycle assessment of biofibres replacing glass fibres as reinforcement in plastics

This article aims to determine the environmental performance of China reed fibre used as a substitute for glass fibre as reinforcement in plastics and to identify key environmental parameters. A life cycle assessment (LCA) is performed on these two materials for an application to plastic transport pallets. Transport pallets reinforced with China reed fibre prove to be ecologically advantageous if they have a minimal lifetime of 3 years compared with the 5-year lifetime of the conventional pallet. The energy consumption and other environmental impacts are strongly reduced by the use of raw renewable fibres, due to three important factors: (a) the substitution of glass fibre production by the natural fibre production; (b) the indirect reduction in the use of polypropylene linked to the higher proportion of China reed fibre used and (c) the reduced pallet weight, which reduces fuel consumption during transport. Considering the whole life cycle, the polypropylene production process and the transport cause the strongest environmental impacts during the use phase of the life cycle. Since thermoplastic composites are hardly biodegradable, incineration has to be preferred to discharge on landfills at the end of its useful life cycle. The potential advantages of the renewable fibres will be effective only if a purer fibre extraction is obtained to ensure an optimal material stiffness, a topic for further research. China reed biofibres are finally compared with other usages of biomass, biomaterials, in general, can enable a three to ten times more efficient valorisation of biomass than mere heat production or biofuels for transport.     

多孔填充材料的防火防爆机理及应用

在液化气体、燃料储罐内填充多孔材料,可有效地减少或避免储罐发生爆炸事故.本文分析了这类材料的防爆机理并简要介绍了其应用情况.     

滇池富营养化水体新型除藻材料的试验研究

通过实验室小试 (2 0L)和滇池水体围栏扩大试验 (30 0m2 ) ,研究新型轻质除藻材料对滇池湖水中藻类的除藻及净化作用。小试结果表明 ,该除藻材料放入滇池水样实验 2 6d后 ,水质明显好转 ,藻类去除率可达 98% ,COD、TN及TP的去除率达到 38%～ 62 %。滇池湖边 30 0m2 水面围栏扩大试验结果显示 ,除藻材料放入试验区水体 1 0d后 ,水体中藻类含量明显减少 ,水体透光率从 55 %增加到 80 % ,水质状况也有很大改善。研究表明 ,该除藻材料是一种具有研究和应用价值的新型水体除藻材料。     

大气二氧化硫(片剂)标准样品的研究

介绍了一种研制大气ＳＯ２(片剂)标准样品的新方法,重点论述了研究过程中对样品进行的均匀性、稳定性检验和定值。研究结果表明,样品均匀性良好、定值可靠,稳定期达３ａ以上。该标准样品已广泛应用于我国环境监测系统,并被批准为国家环境标准样品