Leaching behavior of lignite fly ash with shake and column tests

The maximum concentration of the majority of the trace metals in the leachates from shake and column test of lignite fly ash (LFA) was within the prescribed limits; however, total dissolved solids, total hardness, cations and anions (except K⁺), being above the prescribed limits, may lead to the increase in the hardness and salinity in the soil on the disposal of LFA. Present generation of huge amount of fly ash from thermal power plants (TPPs) is a big challenge concerning contamination of soil, crop produce and surface and ground water bodies due to the presence of some of the toxic trace metals in it. The leaching behavior of alkaline LFA (pH, 10.94), from TPP of Neyveli Lignite Corporation (NLC), India, was investigated by shake and column tests using water and sodium acetate buffer. The leaching of trace metals from LFA was governed by their concentrations, association with the ash particles, leaching duration and pH of the leachate (most influencing parameter). The leaching of metals followed the order: buffer column > aqueous column > aqueous shake > buffer shake test.     

Seismic response of structures with coupled vertical stiffness–strength irregularities

Several seismic design codes around the world restrict the use of theit Equivalent Lateral Force analysis method to structures satisfying structural regularity limits. These regularity limits are based on engineering judgement and lack quantitative justification. One common irregularity is that of a change in vertical stiffness over the building height. This stiffness irregularity is almost always associated with a change in vertical strength over the building height. For this reason, the effect of various realistic combinations of stiffness–strength irregularity in shear‐type buildings is evaluated to quantify regularity limits. Structures analysed had 3, 5, 9 and 15 storeys, and the floor mass at all the levels were kept the same. Both regular and irregular structures were designed in accordance with the Equivalent Lateral Force procedure to produce the same engineering demand parameter. Structural ductility factors of 1, 2, 3, 4 and 6, and target (design) interstorey drift ratios ranging between 0.5 and 3%, were used in this study. The irregular structures were created by modifying specific storey lateral stiffnesses from that of the regular structure. Strengths at these storeys were also modified to ensure realistic relationships between stiffness and strength. The modified structures were then redesigned until the target interstorey drift ratio was achieved at the critical storey. Inelastic dynamic time‐history analysis was conducted to compare the maximum interstorey drift ratio demands of the regular and irregular structures. Simple equations were developed to estimate possible variations in demand due to vertical stiffness–strength irregularity applied at critical locations in structures. Copyright © 2011 John Wiley & Sons, Ltd.     

Reproduction in Galaxias fasciatus Gray (Salmoniformes : Galaxiidae)

A study of the reproductive cycle was made on Galaxias fasciatus Gray from streams on Banks Peninsula, South Island, New Zealand. There was no spawning migration; adults remained in the usual adult habitat to breed. The course of gonad maturation showed that spawning occurred in the autumn, from the end of April to mid‐June. Most males matured at 2 years of age and most females at 4 years old. Egg numbers in the females varied from 3800 to 23 600. Males were predominant in age groups 1–4, females in the older age groups. Amongst fish of potential breeding age there was an excess of males. Circumstantial evidence suggested that eggs were laid among piles of water‐logged debris lodged in pools and backwaters. The larvae, which are briefly described, probably hatch during floods to be swept quickly downstream to the sea.     

建筑工程竣工测量质量控制探讨

竣工测量为规划验收及监督管理提供依据,精度要求较高,测量内容与普通测量有所不同。本文首先介绍了竣工测量过程中应该从项目管理、外业测绘、资料整理、成果检查等方面采取质量控制措施。同时,介绍了竣工测量中应该注意的问题。     

浅谈建筑竣工测量面积计算自动化

建设工程竣工测量面积直接影响城市规划管理部门的行政决策和建设单位的经济效益,所以竣工面积计算的准确性很重要.文章对房屋竣工测量过程中有关房屋建筑面积计算问题进行了探讨,提出了实际工作中的解决方法及建议.     

Stratigraphy of a Lateglacial lake basin sediment sequence at Turret Bank,upper Glen Roy,Lochaber: implications for the age of the Turret Fan

New lithostratigraphical, pollen-stratigraphical and tephrostratigraphical data are presented for a sediment sequence at Turret Bank, a site that lies close to the confluence of the River Turret with the River Roy in Lochaber, the western Scottish Highlands. The site is also adjacent to the inner margin of a major gravel fan, the Glen Turret Fan, the age of which has been debated and has a crucial bearing on the overall sequence of events in Glen Roy, especially concerning the maximum limit of Loch Lomond Readvance (Younger Dryas) ice. Several lines of evidence point to the sediment sequence at Turret Bank having been wholly deposited during the Loch Lomond Stadial-early Holocene transition: (i) the pollen sequence is typical for this transitional period; (ii) varved deposits preserved in the sequence bear a strong resemblance to mid-Stadial varves in a regional master varve scheme for Glen Roy and vicinity (the Lochaber Master Varve Chronology); and (iii) an early Holocene tephra – the Askja-S Tephra – is preserved within the sequence. Some limitations with the new data are considered, but it is concluded that the coherent integration of lithostratigraphic, geomorphological, pollen-stratigraphical and tephrostratigraphical data point to the likelihood that Loch Lomond Readvance ice extended to the inner margin of the Glen Turret Fan, and that the fan was probably constructed by glacial meltwaters at this time.     

The gravel fans of upper Glen Roy,Lochaber, Scotland: their importance for understanding glacial,proglacial and glaciolacustrine dynamics during the Younger Dryas cold period in an Atlantic margin setting

Over the past 200 years significant research effort has gone into explaining the origin of the obvious former shorelines in Glen Roy (the so-called “Parallel Roads”). The large gravel deposit at the mouth of Glen Turret has attracted similar interest, but a solution to its origin and age remains contested: the same applies to the associated gravel fans in upper Glen Roy. This paper presents the results of systematic mapping and instrumental levelling of these features and new evidence from two previously unrecorded gravel fans in the nearby Allt Chonnal valley. Interpretation of altitudinal and lithofacies data indicates that all the fans (including the one at the mouth of Glen Turret) were deposited in a series of ice-dammed lakes during the Loch Lomond Stadial (Younger Dryas). The largest gravel fans were deposited in the shallow lake heads of the 260 m, 325 m and 350 m lakes in upper Glen Roy, infilling these areas to the extent that deposition was in part subaerial. The absence of foreset bedding from the deposits is explained by the relatively shallow depth of lake waters, which inhibited development of classic Gilbert-type deltas and encouraged Hjulström-type fans. The previous assumption that gravel deposition into the 325 m and 350 m lakes was relatively limited is shown to be erroneous. The Allt Chonnal gravel fans, deposited into these lakes, have an estimated combined volume of 6,000,000 m³ deposited in about 200 years. Significant gravel deposition into these former lakes continued at least until glaciers started to retreat in Glen Roy. When glacier retreat began, gravel deposition was reduced by over 85%. This research also concludes that the glacier which deposited the Turret fan emanated from Glen Gloy, supplied not only by ice from the south but also from ice that spilled into Glen Gloy from the adjacent Great Glen. The Loch Lomond Stadial (LLS) ice cap mapped in the Monadhliath Mountains was connected to the west Highland ice cap, which at the time filled the Great Glen. Regional equilibrium line altitude (ELA) estimates, based solely on the Monadhliath LLS ice cap evidence, may therefore be altitudinally too high.     

土力学理论的发展和面临的挑战

随着社会经济的不断发展,土力学所要分析和处理问题的范围越来越广,问题本身也越来越深入和复杂。这些问题主要是由于土与环境的相互作用而产生的。为了分析和处理这些问题,经典土力学需要拓宽和深入发展,它应该包含一些新的现象和新的变量以及相应的新理论。论述了土力学所面临的三大挑战,即①没有严格、统一和完备的土力学理论;②对更具一般意义的非饱和土的行为的研究不够充分,现有的认识也不完善;③没有在多种环境作用下土的统一和完备的多场耦合理论。还论及了其他一些超出经典土力学范围的问题。     

Altitudinal levels and altitudinal limits in high mountains

In lowlands climate-specific processes due to weathering and erosion are dominant, whilst the geomorphology of mountains is dependent on the geologic-tectonic structure, i.e., the energy of erosion that increases according to the vertical. The expression "extremely high mountains" has been established as the extreme of a continuous mountain classification. It has to be understood in terms of geomorphology, glaciology and vegetation. Correspondence of the planetary and hypsometric change of forms is of great value as synthetic explanation. It is confirmed with regard to vegetation, periglacial geomorphology and glaciology. Due to the world-wide reconstruction of the snowline its paleoclimatic importance increases, too. Apart from lower limits the periglacial and glacial altitudinal levels also show zones of optimum development and climatic upper limits in the highest mountains of the earth. According to the proportion of the altitudinal levels a classification as to arid, temperate and humid high mountains has been carried out.     

萨拉乌苏河流域第四系岩石地层及其时间界限

根据对位于鄂尔多斯高原毛乌素沙漠东南部边缘萨拉乌苏河流域的米浪沟湾剖面岩石地层划分并结合年代测试结果,提出了如下一些看法1以组为代表的岩石地层单元的形成时间为离石组>150000aB.P.、萨拉乌苏组150000-75000aB.P.、城川组75000-10000aB.P.、大沟湾组-滴哨沟湾组10000-1000aB.P.、范家沟湾组1000aB.P.-现代.2以上岩石单元与黄土高原相同时期层系具有较好的对比关系离石组\萨拉乌苏组、萨拉乌苏组\城川组和城川组\大沟湾组在地质时代上依次与L₂\S₁(时限为140000aB.P.)、S1\L1(时限为80000aB.P.)和L1\S0(时限为11000-10000aB.P.)大体是等时的.3如以过去全球变化而论,则目前已经可以确切地将米浪沟湾剖面诸岩石单元与深海和大陆冰川最近地质时期的若干氧同位素阶段进行对比,以“”表示为离石组MIS6、萨拉乌苏组MIS5、城川组MIS2～MIS4、大沟湾组+滴哨沟湾组+范家沟湾组MIS1.显然,这一对比关系清楚地说明,我国沙漠万年时间尺度环境演变,与黄土的研究结果一样,在很大程度上受到北半球冰期间冰期气候波动的影响.据此,可以按气候地层进行划分,将离石组、萨拉乌苏组、城川组、大沟湾组+滴哨沟湾组+范家沟湾组的时代分别置于里斯冰期、里斯-玉木间冰期(末次间冰期)、玉木冰期(末次冰期)和冰后期。