Permeable Reactive Barrier for the treatment of contaminated surface water in Katedan industrial development area, Hyderabad, India

Permeable Reactive Barrier （PRB） is an emplacement of inert material （s） in the subsurface, designed to intercept a contaminated plume, provides a preferential flow path through the reactive media, and transforms the contaminant into environmentally acceptable forms to attain concentration remediation goals at the discharge of the barrier. The phenomena, which help in remediation within PRB, are adsorption/sorption, precipitation, oxidation/reduction and biodegradation. Various materials like zero-valent iron, zero-valent bi-metals, natural zeolites, organic carbon, fly ash, zeolites, limestone, activated alumina, apatites, etc. have been tried by many researchers to remove organic and inorganic contaminants. In USA, Canada, and many European countries commercial full-scale and pilot scale PRBs are successfully working. The design and installation of full scale PRBs needs laboratory treatability and dynamic flow column experiments？ The concept of PRB is being applied to treat contaminated surface water in the Katedan industrial area, Hyderabad, India. National Geophysical Research Institute （NGRI）, Hyderabad, India, conducted systematic studies in collaboration with Norwegian Geotechnical Institute （NGI）, Norway, to develop PRB technique to decontaminate the surface water pollution due to industrial effluent. A site assessment study in the Katedan Industrial Area, were carried out and water, soil and sediment from the lakes of the area were found to be polluted with high concentrations of heavy metals like As, Pb, Cr, Cd, Ni, etc. Adsorption studies at NGRI with synthetic samples and in-situ industrial effluent using different reactive media for removing contaminants like arsenic, chromium, cadmium, copper, nickel, lead and zinc have been carried out and yielded satisfactory results. The performance of zero-valent iron and limestone is encouraging in removing As,     

城市化过程中土地征用风险表征及对策

从土地征用基本概念和基本特征着手，描述了土地征用的主要风险，其表现为土地征用权力滥用、侵害失地农民的权益、诱发集体土地黑市、诱发社会矛盾等方面。分析了产生风险的“公共利益需要”缺乏明确界定、土地征用的补偿标准偏低或滞后、土地征用及相关制度不健全或存在缺陷等主要原因。提出了控制与规避风险的对策与措施：严格限定公益性用地范围，提高征地补偿标准，扩大补偿范围，完善相关制度，严格土地征用程序。     

大变形有限元法分析边坡稳定性

边坡稳定性分析的重要任务是确定边坡潜在滑面的位置及相应的安全系数,鉴于坡体位移可在现场监测中直接得到,提出边坡潜在滑面确定的位移判据,采用大变形有限元首先计算出边坡的位移场,然后在开挖面的不同高度作塑性区内的水平位移参考线,依次连接参考线上的位移突变点即得到边坡失稳的潜在滑面位置,分析滑面上的应力以及岩体抗剪强度即得到边坡的整体安全系数。     

用于湿地气候效应模拟的三江平原下垫面数据获取

三江平原是我国沼泽湿地的重要分布区。在20世纪的后50 a中,三江平原在经过几次大规模的开荒后,其下垫面发生了明显的阶段性变化,湿地大面积消失,农田面积不断增加。为了认识20世纪下半叶不同时期三江平原湿地的气候效应,拟采用第三代区域气候模式(RegCM3)来开展研究。而目前被广泛用于RegCM3的GL-CC数据,所反映的研究区下垫面几乎不存在沼泽湿地,这与事实严重不符,所以必须获取三江平原有沼泽湿地存在的真实的下垫面数据,才能得到可靠的湿地气候效应的模拟结果。分别选择了4期(1954年、1985年、1996年和2000年)有阶段代表性的航片、TM影像数据为主要数据源,利用ERDAS8.7和Arcview3.2等软件,首先得到4期研究区的土地利用数据,然后通过土地利用数据类型向模式数据类型的转换,从4期研究区土地利用数据中提取出了三江平原下垫面的模式数据。经过误差分析,认为获取的4期三江平原下垫面模式数据准确的反映出研究区几个时期的湿地下垫面实况,可以作为三江平原湿地气候效应模拟的基础数据。     

Factors controlling the spatial and temporal variability of dust emissions

New field measurement techniques are allowing researchers to better understand how surficial properties affect the temporal and spatial variability of dust emissions. In this paper we review the current understanding of the dust emission process and present new field measurements that examine how three surface properties： roughness, crust strength, and temporal changes of surface properties affect dust emissions. These data were collected using three unique measurement systems developed by our team. Roughness exerts considerable control on the entrainment threshold and emissions of dust from a surface. We have carried out a series of experiments designed to quantify roughness effects on aeolian sediment entrainment and transport in a shear stress partitioning framework. Our results show that the model of Raupach et al. （1993） provides very good agreement with available data to predict the amount of shearing stress on the intervening surface among roughness elements, relatively independent of their size and distribution. However, element size affects the aeolian sediment transport process beyond that attributable only to the reduction of surface shear stress caused by the roughness. Additional interactions of the elements with the saltation cloud appear to reduce the transport efficiency and potentially dust emissions as well. The effect of crust strength on dust emissions was assessed using a newly-developed pin penetrometer, which can measure crust strength in-situ. Previous researchers suggested that variation in crust strength even within a small area could lead to considerable spatial variability in dust emissions. Our measurements showed that crust strength is highly variable over a scale of centimeters. This variability may help to explain some of the observed scatter in field measurements of dust emissions for what appear to be homogeneous surfaces. Variability of dust emissions in time and space was also evaluated using a new instrument, the Portable In-Situ Wind Erosion Lab （PI-SWERL） developed to measure dust emissions from soil surfaces.     

Regional disparity in the changes of agricultura land use intensity in China during 1980-2002

Based on the cost-benefit data （1980-2002） of farm products and China Agriculture Yearbooks, this paper studies the regional disparity in the changes of the agricultural land use in China during the period 1980-2002 from three aspects such as the degree of intensity, the sown area and the abandoned farmland. The results show that： （1） The degree of intensity of land use in the westena region during 1980-2000 has a strong uptrend, but in the eastern and central regions the degree of intensity descends obviously and has shown a continuous downtrend since 1997. （2） The total sown area shrinks notably in the eastern region, while it enlarges constantly in the western region. （3） The sown area in the eastern, central and western regions has gone through a similar cyclic process： down （1980-1985）-up （1985-1991）-down （1991-1994）-up （1994-1999）-down （1999-2002）. However, there are obvious differences in amplitude variation and tendency among them. The sown area has shrunk in the eastern region and expanded in the central and western regions especially before 1999. （4） The most cases of abandoned farmland are reported in the central region, the second in the eastern region and the least in the western region. The abandonment phenomena chiefly occurred during 1992-1995 in the eastern region, and during 1998-2002 in the central region.     

科尔沁沙地土地利用与耕作方式对土壤风蚀的影响

土壤风蚀造成的直接生态后果是土地资源的退化。在春播前两次沙尘暴事件中,对科尔沁沙地几种具有代表性的土地类型的土壤风蚀量及土壤特性进行了野外测定、分析,结果表明:(1)在同一沙尘暴天气下,由于土地利用和耕作方式的不同,土壤风蚀量存在着差异,新垦农地和翻耕农地的风蚀量显著高于未垦草地、免耕农地和麻黄地;免耕农地则与未垦草地的风蚀量相差不大,风蚀危害较轻;麻黄地几乎不受风蚀侵害。新垦农地、翻耕农地、免耕农地、未垦草地、麻黄地两次观测的土壤风蚀量平均值依次为24.59、15.60、2.26、1.46和0.22 g/h.cm2。(2)基于土壤特性计算的土壤退化指数结果表明,新垦农地和翻耕农地发生了较为严重的退化。     

快速城市化过程中城市土地覆被的时空动态特征

1990~2005年间,是广州市经济快速发展和城市景观变化最大的时期,以同时段TM影像解译得到广州市的土地覆被类型图,从数量结构、空间信息及位置转移和景观等方面,分析了广州市土地覆被的动态特征.数量结构的研究结果显示:在快速城市化过程中广州市的耕地、林地等自然资源的利用程度在加大,自1995年起,这种变化的趋势开始减缓;土地覆被类型之间的信息与位置的转移变化频繁,并且表现出空间位置分异的特征.景观特征指数分析结果表明:广州市城市土地覆被向破碎化方向发展,城市建设用地呈扩展之势.     

森林碳汇决策与农村可持续发展研究(英文)

认为有必要在基于碳汇的土地利用和当地可持续发展之间建立一种更加明确的联系.依托一个中国-加拿大合作项目,以中国贵州省黎平县为例,阐述了一种将森林碳汇、森林资源管理以及如何促进当地可持续发展联系起来的综合评估方法,并且着重介绍了能帮助资源管理和规划部门实施这种综合评估的土地利用决策支持工具(LUDST) .