沼泽湿地植物光合特性及固“碳”潜势对外源氮输入的响应

以沼泽湿地典型草甸植被小叶章(Calamagrostis angustifolia)为研究对象,在三江平原进行了野外培养实验,探讨了4个不同氮素输入水平(0(NO)、6(N6),12(N12)、24(N24)g·m-2· a-1)下沼泽湿地植物生长与光合特性的响应特征,并从光合固"碳"的角度分析了小叶章沼泽湿地的固"碳"潜势.结果表明,外源氮输入明显促进了小叶章的株高、叶面积及植株数,显著增加了碳的生物量积累,到植物生长季结束,N6、N12和N24三个施氮水平下,小叶章地上部分生物量分别比对照增加了58.79%、133.11%和190.55%.同时,小叶章叶片全氮含量、叶绿素、可溶性蛋白和游离氨基酸含量也显著增加,净光合速率明显提高,分别比对照增加了20.70%、26.69%和53.54%.从光合固"碳"的角度来看,外源氮输入能够促使沼泽湿地植物通过光合作用固定更多CO2.     

静电除尘器的粉尘非稳态收集过程

为了全面揭示电除尘器粉尘非稳态收集过程,建立完整的非稳态静电收尘理论,根据静电学基本原理,研究了极板粉尘层电荷导人、积累、释放的过程,推导出随粉尘层厚度增长而改变的动态收尘电场强度计算公式,进而得到荷电粒子动态驱进速度公式,最终形成静电除尘非稳态收集理论.研究结果表明,在静电收尘过程中,粒子驱进速度与粉尘比电阻、工作电压、粉尘层厚度等多种因素有关;随粉尘比电阻的升高,收尘效率下降,当供电电压为最佳工作电压时收尘效率最高.针对不同比电阻粉尘进行了多项实验研究,实验结果与理论研究结果吻合.非稳态静电收尘理论成功地解释了实际静电收尘过程中与传统静电收尘理论相矛盾的地方,为静电除尘器的设计及其运行参数的选取提供了更为科学的理论基础.     

从粉煤灰中提取多种微细氧化物的研究

将粉煤灰与Na2CO3按一定的比例混合后焙烧,采用酸碱联合法提取粉煤灰中氧化硅、氧化铝和氧化铁,分析了工艺条件对粉煤灰中氧化物提取率的影响。实验结果表明,从粉煤灰中提取氧化物的最佳条件是:碳酸钠与粉煤灰的比例0.6∶1.0,焙烧温度850℃、盐酸浓度4 mol/L,氢氧化钠浓度2.6 mol/L,浸取时间约6 h。在此条件下得出微细氧化硅、氧化铝、氧化铁的晶体,其平均粒度分别为氧化硅1.107μm,氧化铝1.334μm,氧化铁0.783μm。     

AB工艺污水厂A段不同溶解氧运行效果

对AB工艺城市污水处理厂A段不同溶解氧工况下的实际运行效果进行了监测分析。结果表明:A段按设计参数兼氧运行对BOD5、COD、SS的去除率最高,平均分别达到59.4%、77.2%、73.2%;总氮的去除率随A段溶解氧含量影响不大,平均为46.8%;总磷的去除率随溶解氧含量的增大而升高,最高可达80.2%。     

芳香有机物电化学氧化降解的研究

为了考察物质结构对难生物降解芳香化合物电催化氧化的影响,实验研究了典型的酚类和胺类芳香污染物的电化学氧化降解。结果表明:电催化氧化技术可有效处理水中的芳香化合物,苯环上取代基对有机物的电催化降解活性有很大影响,带有供电子取代基团的芳香化合物的电催化降解速率比带有吸电子取代基团的芳香化合物的电催化降解速率快。处理2 h,苯酚、苯胺和甲苯胺接近完全去除,对氯苯酚和对氯苯胺的去除率超过90%,对硝基苯酚和2,4-二氯酚的去除率也达到70%左右。     

Organically bound tritium (OBT) for various plants in the vicinity of a continuous atmospheric tritium release

In order to quantify tritium impact on the environmental, we studied vegetation continuously exposed to a tritiated atmosphere. We chose lichens as bio-indicators, trees for determination of past tritium releases of the Valduc Centre, and lettuce as edible vegetables for dose calculation regarding neighbourhood. The Pasquill and Doury models from the literature were tested to estimate tritium concentration in the air around vegetable for distance from the release point less than 500m. The results in tree rings show that organically bound tritium (OBT) concentration was strongly correlated with tritium releases. Using the GASCON model, the modelled variation of OBT concentration with distance was correlated with the measurements. Although lichens are recognized as bio-indicators, our experiments show that they were not convenient for environmental surveys because their age is not definitive. Thus, tritium integration time cannot be precisely determined. Furthermore, their biological metabolism is not well known and tritium concentration appears to be largely dependent on species. An average conversion rate of HTO to OBT was determined for lettuce of about 0.20-0.24%h(-1). Nevertheless, even if it is equivalent to values already published in the literature for other vegetation, we have shown that this conversion rate, established by weekly samples, varies by a factor of 10 during the different stages of lettuce development, and that its variation is linked to the biomass derivative.     

Effect of bioethanol and thermal barrier coating on the performance of dual fuel engine operating on Honge oil methyl ester (HOME) and producer gas induction

Alternative fuels have numerous advantages compared to fossil fuels as they are renewable, biodegradable; provide energy security and foreign exchange saving besides addressing environmental concerns and socio-economic issues as well. Renewable fuels can be used predominantly as fuel for both transportation and power generation applications. Improved engine performance with reduced engine exhaust emissions is a major research objective in engine development. Today, the use of biomass derived producer gas is more relevant for addressing rural power generation and is a promising technique for controlling both nitric oxide (NO_x) and soot emission levels. In view of this, exhaustive experiments on the use of Honge oil methyl ester (HOME)–Producer gas in a dual fuel engine have been carried out with an intension of improving its fuel efficiency. This paper mainly presents results on a single cylinder four stroke direct injection diesel engine operated in dual fuel mode using HOME–Producer gas combination with and without bio-ethanol addition and thermal barrier coating (TBC). Further, the results were compared with diesel–producer gas mode of operation. Experimental investigation on dual fuel operation using HOME+5% bioethanol (BE5)–Producer gas operation with TBC showed 12.35% increased brake thermal efficiency with decreased hydrocarbon and carbon monoxide emissions and increased NO_x emission levels compared to HOME–Producer gas mode of operation.     

Sustainable options of post treatment of UASB effluent treating sewage: A review

The upflow anaerobic sludge blanket (UASB) process is reported to be a sustainable technology for domestic wastewaters treatment in developing countries and for small communities. However, the inability of UASB process to meet the desired disposal standards has given enough impetus for subsequent post treatment. In order to upgrade the UASB based sewage treatment plants (STPs) to achieve desired effluent quality for disposal or for reuse, various technological options are available and broadly differentiated as primary post-treatment for the removal of organic and inorganic compounds and suspended matter; secondary post-treatment for the removal of hardly degradable soluble matter, colloidal and nutrients; and polishing systems for removals of pathogens. Hence, this paper discusses the different systems for the treatment of UASB reactor effluent treating sewage. Additionally, a comparative review, an economic evaluation of some of the emerging options was conducted and based on the extensive review of different integrated combination, i.e. UASB-different aerobic systems, a treatment concept based on natural biological mineralization route recognized as an advanced technology to meet all practical aspects to make it a sustainable for environmental protection, resource preservation and recovering maximum resources.     

煤巷掘进过程中粉尘浓度影响因素分析

为了掌握煤巷掘进过程中粉尘浓度变化的影响因素,根据气固两相流理论,针对矿井掘进工作面的特点,采用计算流体力学的离散相模型（DPM）考察了掘进巷道风速、风筒直径、风筒出风口到掘进工作面距离以及风筒的悬挂高度对粉尘浓度变化的影响。结果发现：当掘进巷道风速为0.25-4 m/s时,提高巷道内的通风风速,可以降低巷道内的粉尘浓度,缩短呼吸性粉尘浓度达到稳定的时间,减小工作面粉尘的危害;有利于通风除尘的风筒相关参数为风筒直径0.4-0.6 m、风筒出风口到掘进工作面距离6-7 m、风筒悬挂高度2.0-2.2 m。