生态足迹计算模型应用中热点问题及探讨

简要介绍了生态足迹计算模型,论述了近年国际上争论的几个主要热点问题,数据的准确完整性,初级产品与二级产品,均衡因子与产量因子,全球产量与本地产量,以及能源足迹计算等,并对其进行了探讨和指出今后研究发展的方向。     

Petroleum contaminated soil in Oman: Evaluation of bioremediation treatment and potential for reuse in hot asphalt mix concrete

This paper presents a study that aims at evaluating the leaching characteristics of petroleum contaminated soils as well as their application in hot mix asphalt concrete. Soil samples are environmentally characterized in terms of their total heavy metals and hydrocarbon compounds and leachability. The total petroleum hydrocarbon (TPH) present in the PCS before and after treatment was determined to be 6.8% and 5.3% by dry weight, indicating a reduction of 1% in the TPH of PCS due to the current treatment employed. Results of the total heavy metal analysis on soils indicate that the concentrations of heavy metals are lower when extraction of the soil samples is carried out using hexane in comparison to TCE. The results show that the clean soils present in the vicinity of contaminated sites contain heavy metals in the following decreasing order: nickel (Ni), followed by chromium (Cr), zinc (Zn), copper (Cu), lead (Pb), and vanadium (V). The current treatment practice employed for remediation of the contaminated soil reduces the concentrations of nickel and chromium, but increases the concentrations of all remaining heavy metals.     

高氟温泉水中氟在周边水环境中的分布特征与评价

针对温泉水中高氟现象,本实验利用离子选择性电极法,分析测定高氟温泉水周边河水中氟含量及河水底泥中氟含量。通过对高氟温泉水分布特征的研究可初步得知,温泉中高氟在周边水环境中分布因其氟含量大、不易被重视,对环境的影响相对较大。     

Effect of aging level on viscoelastic properties of asphalt binder containing waste polyethylene

Due to inherent advantages, waste polyethylene (generated from domestic sources) has been used as asphalt modifier. This article discusses viscoelastic properties of the polyethylene modified asphalt binder. Several asphalt concrete mixtures were designed by varying polyethylene and asphalt content. Shredded polyethylene incorporated into asphalt concrete by dry mixing process. Using optimised asphalt content (at several polyethylene percentages), mixtures were prepared and compacted. These compacted specimens were aged for different duration in convection oven. Asphalt binder (from aged specimens) was extracted and tested for its viscoelastic properties using dynamic shear rheometer. Comparison of mastercurves indicated increase in complex modulus and decrease in phase angle values with addition of polyethylene at all reduced frequencies. However, the extent of change was highly dependent on frequency, aging duration and polyethylene content. This indicates that the addition of polyethylene provides more resilience to asphalt binder especially with less aging time. Storage modulus mastercurves (at lower frequencies) and relaxation modulus values (at longer time) indicate polyethylene provides additional stiffening to binder. Further, changes in viscous modulus with addition of polyethylene were marginal. Overall results indicate that waste polyethylene improves the properties of asphalt binder over extended loading period when heated for less time during mixing.     

辐射板强化喷管换热与红外抑制效果试验研究

试验研究了在发动机喷管中加装金属辐射板前后,喷管壁面温度、热喷流温度与喷管红外辐射特征的变化。结果表明,加装金属辐射板后,热喷流与喷管壁面之间的热量传递显著增强,热喷流中心温度降低,壁面温度明显升高,在90°方向上,热喷流3～5μm波段的红外辐射强度降低了38.5%。文中从热喷流、喷管壁面以及金属辐射板等相关部件的温度变化情况对红外辐射强度的变化原因进行了解释。      

国内船舶碰撞事故科研产出及主题趋势挖掘

为了全面认识国内船舶碰撞研究的整体现状及趋势,基于中国知网的2000—2016年506篇船舶碰撞学位论文和1957—2016年1 620篇期刊论文,使用科学计量和知识图谱的方法进行了可视化分析。结果表明:学位论文和期刊论文的产出主要集中以大连海事大学、上海海事大学、上海交通大学以及武汉理工大学为核心形成不同的研究团队。关于船舶碰撞的学位论文主要集中在AI、船舶避碰、数值仿真等方面,期刊论文的热点主要分布在船舶避碰、碰撞事故、碰撞危险等方面。整体来看,2000年以后学位和期刊论文在研究上的趋势是相近的,都在关注AI、数值模拟方法和碰撞责任主体等方面的避碰主题,近期新兴的研究更加关注在一些船舶碰撞微观的层面。     

西蒙得木对金沙江干热河谷生态保护的作用

金沙江干热河谷生态条件恶劣，水土流失严重，对长江流域中下游特别是三峡大坝存在着极大的负面影响。治理长江流域，保护三峡大坝的重要源头是金沙江干热河谷的生态环境建设。西蒙得木生长的生态环境与金沙江干热河谷的生态环境非常相似，并且西蒙得木具有极高的经济价值，因此在金沙江干热河谷种植西蒙得木，既能改良生态环境，又能发展当地经济。     

室外风压、火风压对建筑物热压中和面位置的影响

首次提出风压与热压可完全分解 ,风压不改变热压本身的压力特性的观点 ,确定风压与热压共同作用下的新的中和面 ;提出火灾层火风压造成的空气渗进、烟气的排出过程属内部循环的观点 ;对于火灾烟气窜入建筑内部竖井通道的情况 ,则根据中和面上下各楼层总渗进、渗出平衡的观点 ,确定火灾引起的新的中和面位置。     

分光光度法测定浮游植物叶绿素a的比较研究

对浮游植物叶绿素a测定方法中的国家标准方法丙酮三色法与目前国际上使用的方法乙醇单色法进性了比较,实验材料使用了实验室培养的栅藻,避免了藻类种类对于测定结果的影响。实验结果显示,乙醇法的萃取率高于丙酮法,但由于乙醇法实验条件的难以控制,其结果的方差较大;两种方法的测定结果间的相关性很好,相关系数为0.9998,因此得出两种方法测定结果间的换算公式为Chla乙醇=1.658 Chla丙酮-5.821。还研究了乙酸滤膜的溶解对于测定结果的影响,结果表明乙酸滤膜的溶解未对测定结果造成明显的影响。     

NiTi形状记忆合金的加工方法

对NiTi形状记忆合金的多种加工方法如锻造、热挤压、轧制和拉拔、冷加工、粉末成形、包套碎片挤压成形、溅射沉积加工等进行了详细介绍。