Recovery of gold by chicken egg shell membrane-conjugated chitosan beads

We have successfully prepared a bead-type adsorbent from two materials with different adsorption characteristics. Heavy metals were removed by greatly swollen egg shell membrane-conjugated chitosan beads. The egg shell membrane accumulated and removed precious metal ions from a dilute aqueous solution with a high affinity in a short contact time. Experiments suggested that chitosan beads could take up gold ions with great capacity and selectivity by conjugation with egg shell membrane. Under certain conditions, the selective removal of gold and copper in a mixture of gold and copper ions by egg shell membrane-conjugated chitosan beads was 100% and 2%, respectively. Egg shell membrane-conjugated chitosan beads can be seen as a promising material to recover gold in wastewater from various industries, such as electroplating.     

Influences of Magnesium <Emphasis Type="Italic">tri-</Emphasis>Silicate on the Physical,Mechanical, and Degradable Properties of Ultraviolet (UV) Radiation Cured Plain Board Surface

A series of formulations were prepared with different percentages of oligomer, epoxy diacrylate (EA-1020 ), monomer, 1,6 Hexane diol diacrylate,(HDDA) and different percentages of filler (Magnesium tri-silicate, Mg₂Si₃O₈). Irgacure 369 [2-Benzyl-2-dimethyl-amine-1 (4-morpholinophenyl) butanone-1] was used in the formulations as photoinitiator. Ultraviolet (UV) cured thin polymer films were prepared from these formulating solutions on clean glass plates. Pendulum hardness (PH), gel content and macro scratch hardness (MSH) of the UV cured films were studied. One percent Mg₂Si₃O₈ containing formulation showed the premium properties. The substrates (plain board) were coated by these formulating solutions and cured under the same UV lamp at different intensities of radiation. Various properties of the coated surface such as PH, gloss, adhesion, abrasion and MSH were investigated. The base coat containing 1% Mg₂Si₃O₈ and top coat containing 48% HDDA produced the best performance among all the formulations inspected. The degradable properties in different weathering conditions on PH, gloss, adhesion, abrasion and MSH were measured. The surface cured with the optimized formulation (E) again yielded the minimum loss of the properties.     

大空间建筑火灾中热烟气层发展规律的理论分析

对几类典型的大空间建筑火灾中热烟气层的发展规律进行了理论分析,并和文献中的实验结果进行了对比。理论分析表明热烟气层的发展速率除了与火源的功率和大空间的几何尺寸有关外,还取决于火羽流的种类。给出了轴对称火羽流、二维线性溢流和沿墙壁的二维线性火羽流情况下的热烟气层发展速率的表达式,对大空间建筑的火灾安全设计与灾害预测具有指导意义。     

城市内涝灾害风险评估及综合应对研究进展

城市内涝灾害风险评估是城市内涝灾害管理,减少内涝灾害损失的有效途径。基于自然灾害风险评估理论,对城市内涝形成机理和风险评估方法进行了概述。从规划、建设和管理三个层面提出应对城市内涝的总体思路和技术框架,并指出相应的关键技术问题。最后,指出未来城市内涝灾害风险评估和综合应对的研究工作重点:①加强城市内涝形成机理的研究;②完善城市内涝灾害风险评估的理论与方法;③构建城市内涝灾害数据库;④城市内涝应对与城市水生态修复相结合。     

基于GIS的松花江干流暴雨洪涝灾害风险评估

以黑龙江省内的松花江干流流域作为研究区,从现代灾害风险理论出发,综合运用GIS空间分析和灾害风险评估数学方法,对松花江干流流域的暴雨洪涝灾害风险进行了定量评价.研究利用遥感数据和社会经济数据,在空间分析基础上,通过对暴雨洪涝灾害的危险性、承灾体的暴露性、脆弱性以及区域防灾减灾能力的分析,确定影响各个县市暴雨洪涝灾害风险的具体方面.并将因子集成为洪涝灾害风险指数(FDRI),在此基础之上绘制出松花江干流流域的洪涝灾害风险区划图,结果表明松花江干流洪涝灾害风险以哈尔滨和佳木斯两市最大,上游洪涝灾害风险大于下游.     

不同地震序列类型地震的特征性质研究

收集整理了1993年以来的地震资料,建立M5地震和M6地震两个样本组,选取发震断层、震源复杂性、视应力3个参数,使用模糊等价关系的聚类分析方法对地震进行分类,把具有相同性质的地震归为同一类,研究孤立型、主余型、多震型地震的某些特征性质。结果表明:1孤立型地震性质:震源错动方式简单,应力降高或很高,视应力低或很低,震源区介质非均匀程度低;2多震型地震性质:对于走滑断层地震,震源错动方式复杂,应力降低或很低,视应力偏高或很高,震源区介质非均匀程度较高。     

Nitrogen-retaining property of compost in an aerobic thermophilic composting reactor for the sanitary disposal of human feces

Aerobic composting is a method for the sanitary disposal of human feces as is used in bio-toilet systems. As the products of composting can be utilized as a fertilizer, it would be beneficial if the composting conditions could be more precisely controlled for the retention of fecal nitrogen as long as possible in the compost. In this study, batch experiments were conducted using a closed aerobic thermophilic composting reactor with sawdust as the bulk matrix to simulate the condition of a bio-toilet for the sanitary disposal of human feces. Attention was paid to the characteristics of nitrogen transformation. Under the controlled conditions of temperature at 60°C, moisture content at 60%,anda continuous air supply, more than 70% fecal organic removal was obtained, while merely 17% fecal nitrogen loss was observed over a two-week composting period. The nitrogen loss was found to occur mainly in the first 24 h with the rapid depletion of inorganic nitrogen but with an almost unchanged organic nitrogen content. The fecal NH₄-N which was the main component of the inorganic nitrogen ( > 90%) decreased rapidly in the first day, decreased at a slower rate over the following days, and finally disappeared entirely. The depletion of NH₄-N was accompanied by the accumulation of NH₃ gas in the ammonia absorber connected to the reactor. A mass balance between the exhausted NH₃ gas and the fecal NH₄-N content in the first 24 hours indicated that the conversion of ammonium into gaseous ammonia was the main reason for nitrogen loss. Thermophilic composting could be considered as a way to keep a high organic nitrogen content in the compost for better utilization as a fertilizer.     

亚硝态氮和氨态氮急性胁迫下曼氏无针乌贼幼体血液的生化指标

将曼氏无针乌贼幼体置于24 h半致死剂量的亚硝态氮和氨态氮溶液中(10 mg·L-1 NaNO2和300 mg·L-1 NH4Cl),检测6、12和24 h各点及对照组曼氏无针乌贼幼体血液生化指标的变化.结果表明,随着处理时间的延长,NaNO2处理组血细胞密度(THC)(p＜0.05)、甘油三酯(TG)(p＜0.05)...     

彗星电泳法测定双酚A对雄性幼龄小鼠脑细胞的DNA损伤

双酚A是一种日常生活中无处不在的环境雌激素,具有生殖和神经毒性,但低剂量长期暴露对发育期青少年的危害性常常被低估或忽视。本研究以4周龄雄性清洁级小鼠为实验对象,以茶油作为溶媒对照,分别以双酚A浓度为0μg·m L-1、0.1μg·m L-1、10μg·m L-1和1 000μg·m L-1的茶油灌胃小鼠8周,然后利用彗星电泳法检测各组小鼠脑细胞的DNA损伤。结果显示,不同浓度双酚A暴露8周后,彗星电泳图像显示小鼠脑细胞DNA出现不同程度的损伤,随着暴露剂量的增加,带有彗尾的脑细胞比率从对照组小鼠的9.5%分别升高到暴露组小鼠的34.5%、36.0%和50.5%,细胞总体的尾部DNA含量、尾长和尾矩也都逐渐增加,而且各双酚A暴露组小鼠与溶媒对照组小鼠脑细胞都具有显著性差异(P0.01),这说明中长期双酚A暴露(包括低浓度环境暴露)会导致雄性幼龄小鼠脑细胞的DNA损伤。     

水环境中4-叔辛基苯酚的污染现状与生态风险评估

4-叔辛基苯酚是一种具有内分泌干扰效应的有机污染物,已广泛存在于环境介质中,有必要关注其生态风险。本文依据2010年以来4-叔辛基苯酚在我国8个湖库、11条主要河流、9个城市市内河流、污水处理厂进出水以及近海的水体和沉积物的环境暴露浓度数据,以及4-叔辛基苯酚的急慢性毒性数据。采用物种敏感性分布法(species sensitivity distribution, SSD)估算了4-叔辛基苯酚淡水、海水以及沉积物的预测无效应浓度(predicted no effect concentration, PNEC),并采用商值法对其进行了生态风险评估。结果表明,长江水系、珠江水系中4条河流地表水部分点位生态风险高,且珠江水系的风险相对较高;9个城市中的上海、广州、宁波、济南、太原和东莞6个城市河流部分点位生态风险较高;28个淡水地表水点位中,高生态风险占比为35.7%。10处有浓度数据报道的淡水沉积物中,9处为低风险,1处为中风险,海水及海洋沉积物均为低风险,4-叔辛基苯酚对我国淡水环境的影响应该引起重视。