Explosive impulse on plates

This paper describes a series of very small scale model tests that were conducted in support of a full scale test program conducted by the Army Research Laboratory at Aberdeen, Maryland for the US Navy to investigate the impulse delivered to a military vehicle by a buried land mine. The full scale tests were conducted in July of 2004 and investigated the effect of various parameters on the impulse delivered. The vehicle was represented by a steel plate and depth of burial, standoff distance, and explosive size (up to 10 pounds of TNT) were changed in the seven tests conducted for the Navy. The full scale tests were conducted in saturated sand. The tests described in this paper used a maximum charge size of 3.3 gm of RDX and PETN. Each of the tests conducted for the Navy were simulated by the small scale tests and a prediction of the impulse that would be measured for each of the tests was made. The small scale tests (as well as the full scale tests results) were also used by the developers of various numerical codes that were also used to predict the impuse that would be measured in the full scale test series.This paper is accompanied by a paper by Taylor et al. (Taylor, L. C., Skaggs, R. R. and Gault, W., 2005, Vertical impulse measurement of mines buried in saturated sand, Fragblast, International Journal for Blasting and Fragmentation, 9, 19-28) in this issue of FRAGBLAST. In the next issue of FRAGBLAST several additional papers will be published. These will be the results of the numerical codes that were used to predict the impulse.     

Rehabilitation of storm water collection systems of urban environment using the small roads as conveyance channels

In this study a new grated inlet is proposed for small roads which do not have storm water collection systems. A setup was designed and constructed in the laboratory conditions to calibrate the grated inlet. The inlet is suggested to be installed at the end of the road where the road itself joins to another road or to a street. Thus, newly installed inlet will collaborate with existing storm water collecting system of the main road. Inlet structure covered by slots is installed across a 0.90-m wide flume which will act as a small road. The slots are longitudinal and parallel to the flow direction in order to curtail clogging. It is a tilting flume and both subcritical and supercritical flow regimes can be observed. The intercepted flow by the inlet is measured and the efficiency of the inlet is obtained in terms of longitudinal slope and the Froude number. It is observed that the grate efficiency gets higher as the longitudinal slope approaches to horizontal. Further the grate efficiency also depends on the total flow through the channel. As flow increases in the channel, the efficiency of the grate increases within the limit of the inlet or discharge channels capacity.     

壳幔Rb—Sr混合等时线及其地质意义

本文利用二元混合模型讨论了壳幔物质的不同混合环境对Ｒｂ－Ｓｒ等时线年龄的影响。一般情况下,混合作用将使岩体的同位素年龄变大;若地壳物质在混合之前经受过Ｒｂ丢失和（或）Ｓｒ获得事件,则等时线斜率的变化较大,可能得到很大的年龄和异常低的初始同位素比值,甚至斜率为负值。对一组分离的底辟小岩体而言,同一底辟岩体作矿物内部等时线能够得到结晶年龄,但用不同岩体的全岩得到的等时线则可能给出围岩年龄（条件是各底辟     

Importance of coloured inversion technique for thin hydrocarbon sand reservoir detection – A case in mid Cambay basin

Cambay basin is an intra-cratonic rift graben formed as a result of rifting which was occurred in late Cretaceous with Deccan lava eruption through linear trending NNW to SSE directional basin. The Deccan basalt forms the basement over which more than 7–11 km thick piles of Tertiary sediments have been deposited during syn-rift and post-rift phases of basin development. Cambay basin has been considered as one of the significant hydrocarbon prolific basin in India. The biggest challenge in current days for this basin is further exploration or exploration under development stage in small marginal field or unexplored left out areas in the basin part as most of the areas are already explored/discovered by various small to big E&;P (exploration &; production) industrial players. In this present study one such small marginal field has been chosen for “Exploration under Development” portfolio in mid Cambay basin. The amount of oil-in-place volume, investment and techno-economics analysis of small marginal field has made this study area. In view of further hydrocarbon exploration in this area this kind of study will provide a robust support in limited dataset. The reservoir sand quality of the study area is discrete, thin and less permeable. This kind of sand body detection through classical seismic interpretation approach is difficult and there will be always a big amount of uncertainties for findings the pay reservoir sand. In view of the limitation of available data and challenging geological setup of the reservoir, a quantitative approach has been taken to detect the thin reservoir sand in this study area. Primarily coloured inversion technique has been applied on post-stack seismic data based upon well to seismic correlation and reservoir sand detection in seismic interpretation and well log property analysis. This technique has produced higher detectability impedance/property volume with respect to normal post-stack seismic data signature. Based on high contrast impedance/elastic property further seismic based attribute analysis on reservoir section has been performed. The attribute analysis has been made along surface and 3D seismic data level, provided clear image about the thin hydrocarbon sand reservoir. Based upon quantitative interpretation approach coloured inverted volume the prospect was chosen for further drilling in the study area and drilling of that sand was turned to be a hydrocarbon discovery prospect. The unconventional approaches e.g. coloured inversion with limited dataset for this kind of small marginal field has potential to find the hydrocarbon.     

考虑盾构铰接作用的小半径曲线隧道开挖诱发地层沉降分析

目前针对小半径曲线隧道开挖诱发地层沉降的理论研究均将盾构机视为一个连续的整体,未考虑盾构机铰接装置带来的影响,由此不能正确评估小曲率盾构开挖路径变化带来的超挖效应等。首先,根据盾构机铰接位置以及盾构机与小曲率隧道开挖路径的几何位置关系,得到了小曲率隧道开挖过程中不同盾构铰接位置超挖量及盾构铰接角计算公式;其次,基于镜像法及Mindlin解,求解了铰接盾构施工时因超挖地层损失、盾尾地层损失、开挖面不均匀推力、盾壳不均匀摩擦力及盾尾处注浆压力等共同影响的地层沉降;最后,采用工程监测数据与理论解进行对比验证,得到较好的一致性。此外,针对隧道转弯半径、前盾长度、盾构铰接角及超挖量等进行了参数分析。分析结果表明：不考虑盾构铰接装置的影响将过高估计地层损失而导致地层沉降预测值偏大。随着转弯半径的减小,前盾长度、盾构铰接角及超挖量的增加,地层沉降增大,但其值变化均对开挖面前方沉降影响较小,对开挖面后方沉降影响较大。在开挖面后方,随着与开挖面距离的增大,当转弯半径取值较小,前盾长度、盾构铰接角及超挖量取值较大时,纵向地表沉降呈先增大后减小趋势。     

重庆市两江隧道合理覆盖层厚度研究

重庆市拟通过朝天门两江隧道等来实现渝中半岛、江北城和南岸弹子石三地之间的快捷连接。江底隧道的覆盖层厚度十分重要。如果覆盖层厚度太小,江底隧道工作面就有面临严重的失稳问题和江水涌入的危险,会使辅助工法的投入增大,另一方面覆盖层厚度太大将增加江底隧道的长度、坡度与造价。分别采用工程类比法与数值模拟法确定了重庆市朝天门两江隧道越江段钻爆法施工的合理覆盖层厚度。     

Geochemical aspects of permeability controlled partial melting and fractional crystallization

Magma accumulation in the mantle requires that the mantle be permeable. Experimental investigations show that the permeability threshold first will be attained after a certain degree of partial melting. The influence of the permeability threshold on the composition of partial melts is evaluated using the fayalite-forsterite system as an example. In addition the variation in trace element concentrations are calculated for different distribution coefficients. Primary magmas formed by accumulation when a minimal degree of partial melting is required for permeability display a remarkably small variation in composition up to 30% partial melting. It is suggested from REE abundances that primary tholeiitic magmas have been generated by permeability controlled partial melting. The compositions of the primary magmas generated by permeability controlled partial melting will not differ much from the compositions obtained by batch melting, but the degrees of partial melting will differ for similar compositions.     

微量陨石激光熔样稀有气体测定方法

微量陨石激光熔样稀有气体测定方法是一种可以在微米尺度上对几毫克陨石样品进行准确稀有气体同位素分析的方法,克服了传统全岩熔融法在测量时存在样品用量大、前处理过程复杂和样品稀有气体分布不均导致不同组分的宇宙射线暴露历史无法进一步区分等问题。但是由于该方法所用样品体积小和样品用量低,要求实验室具有超低本底的稀有气体提取系统,目前国内在微量陨石稀有气体分析技术方面尚处于起步阶段。本文采用金刚石激光样品窗成功研制了超低本底的气体提取系统,通过系统体积标定和天平称量误差、热本底、干扰元素、质量歧视及质谱灵敏度等参数的校正,在中国科学院地质与地球物理研究所建立了微量陨石激光熔样稀有气体测定方法,并对毫克级微量钙长辉长无球粒陨石Millbillillie粉末标样进行了稀有气体同位素含量和比值测定,计算获得准确一致的宇宙暴露年龄。该方法的建立,将为我国迅速发展的比较行星学和深空探测提供重要技术支撑。     

Predation Risk Experienced by Mummichog, Fundulus heteroclitus, in Intertidal and Subtidal Salt Marsh Habitats

It is often presumed that salt marshes provide a predation refuge for small fishes, but predation risks have rarely been compared in intertidal and subtidal habitats, making the importance of salt marshes as a predation refuge speculative. We measured relative survival of tethered mummichog (Fundulus heteroclitus) in four habitats in a salt marsh?Ctidal creek system: unvegetated and vegetated intertidal areas and the subtidal creek at high and low tide. At high tide, mummichog in the intertidal zone had significantly higher survival than in the subtidal creek in June through August. Survival rates in unvegetated and vegetated intertidal habitats were not significantly different, suggesting that higher intertidal survival was due to less abundant predators compared with the creek, rather than predators being less effective in vegetation. The lower predation risk experienced by mummichog in the intertidal marsh suggests that access to intertidal habitats will be important for production of small estuarine fishes.     

The place of ecological–geophysical studies in the system of urban ecology

According to the forecasts of the World Health Organization, 70% of the world’s population will have lived in large and small cities by 2050. This means that more than two-thirds of the planet’s population will become a part of new natural-technical formation, that is, geobiotechnoecosystems. Such ecosystems are characterized by profound changes in natural properties during active human impacts and by acquiring new qualities. The changes manifest themselves in all ecological functions of the terrestrial spheres: the atmosphere, the hydrosphere, and the lithosphere, including a change in the geophysical (energetic) potential as well. The presented material can be considered as a basis for the formation of Geophysical Urban Ecology, which is a new scientific and practical field.     

Hydrological and hydrogeological characteristics of Wadi el Mujib catchment area,Jordan

Hydrological and hydrogeological data in the area have been verified to evaluate the availability and the potentiality of the water resources for the proposed damsites in the Wadi el Mujib catchment area, which is considered a semiarid to arid region. The quantity of the surface waters is very small compared with the surface area of the basin, however, due to the shortage of precipitation in the country and the necessity to attain socioeconomic objectives, the investigation of these waters has become more vital. The most reliable exploitation can be essentially achieved by constructing small storage dams on the suitable sites in order to benefit from the flood waters coming from the main wadis. For the above purpose, the hydrogeological and hydrological study of Wadi el Mujib catchment area was carried out, where the Wadi Mujib dam site will be constructed. The hydrogeological investigation of the groundwater was performed by constructing a groundwater contour map of the Amman-Wadi Es Sir aquifer (B2/A7) so as to verify the groundwater flow system and to determine the potentiality of the aquifer from the hydraulic parameters obtained from the pumping test analysis. The hydrological feasibility study of the dam was carried out by evaluating the water balance for a long-term period (1970 to 1990) in order to obtain reliable data that can be used to estimate the recharge to B2/A7 aquifer. In addition, a frequency analysis was performed to estimate the flood design of the reservoir area as well as the spillway at the proposed dam site.     

综合利用小水库群简易优化调度

提出一种以弃水量最小为目标函数的水库群简易优化调度方法──动态空库系数法。任一时刻某水库的空库系数反映该水库在该时刻的蓄水能力和供水能力。本法用时段初各水库空库系数的大小决定水库群的蓄放水次序,在满足约束条件下,时段末保持各水库的空库系数相等,由此尽可能地拦蓄径流,使弃水量最小。     

From labour lines to urban living: Health transition in Mauritius

Recently Mauritius has witnessed a rapid urbanization process. In such a small space, with a high population density and an improving economic situation — shifting from an agricultural-based to an industrial one — it is possible nowadays to distinguish the growth of major villages into well-structured urban centres. Contrary to the trend observed in some economically less developed countries (LDCs), health characteristics have veered mostly towards trends exhibited by economically more developed countries (MDCs). This paper will describe briefly the urbanization processes at work in Mauritius and will explore the changing health characteristics and provisions observed in such a small island state. It will try to lay the foundation for comparison with other small island states transcending the MDC/LDS divide.     

Flooding of Sinking Creek,Garretts Spring karst drainage basin,Jessamine and Woodford counties,Kentucky, USA

Tashamingo Subdivision in Sinking Creek karst valley, a tributary of the Garretts Spring drainage basin in Jessamine and Woodford counties, Kentucky, was flooded in February 1989. To determine the cause of flooding, the groundwater basin boundary was mapped, discharge data were measured to determine intake capacity of swallets, and hydrologic modeling of the basin was conducted. Swallet capacity was determined to be limited by the hydraulic parameters of the conduit, rather than by obstruction by trash. Flooding from a precipitation event is more likely, and will be higher, when antecedent soil moisture conditions in the watershed are near saturation. Hydrologic modeling shows that suburban development of 20 percent of the southeast basin will cause a small increase in flood stage at Tashamingo Subdivision.     

Regional Distribution and Prospects of Potash in China

China was formed by amalgamation of several small continental blocks (cratons), micro, blocks and orogenic belts in different paleoclimatic settings. It may be correlated with other continental blocks but has its own specific characteristics; therefore the tectonic environments of China’s marine and continental saline basins and salt, and potash, forming environment have some specific characteristics: multiple phases of salt formation, difference in salt, forming ages, migration and concentration of salt, forming processes and diversity of component materials, as well as small sizes of marine saline basins and great changes of saline basins in the late stage and occurrence of abundant liquid mineral resources. The nature of the tectonic basement exerted a key controlling effect on the formation of potash basins. The stable tectonic region was favorable for potash concentration in a quasi, stable region, and quasi, and the quasi-stable region was favorable for salt concentration and potash formation in a local stable tectonic region. Most China’s major ancient saline basins occur in “quasi, cratons (continental block)”; especially all the marine saline basins occur in continental blocks with the Precambrian basement. These regions are the key ones for potash search. Most relatively large, scale soluble salt deposits are developed in relatively stable continental nuclei. According to the characteristics of the tectonic domains where China’s salt, forming basins are located, the North China, Yangtze and Tarim, Qaidam salt minerogenetic domains and the northern Qiangtang, western Yunnan salt minerogenetic belt may be distinguished. Their salt and potash prospects will be discussed separately.     

分布式水文模型子流域划分中界河、海岸线的处理研究

流域划分是分布式水文模型最重要的基础工作之一.有的区域以界河或者海洋为边界,界河、海岸线上河流出口点众多,如果按照传统流域划分方法,不仅出口点定位工作量大,而且容易遗漏部分小的河流出口点,导致模拟范围与研究区域偏离过大.针对这些问题,本文提出了一种子流域划分过程中界河、海岸线的处理方法.即,通过对DEM进行特殊处理,生成界河、海岸线的模拟河网,然后选择界河的末端和海岸线的任意一端作为出口点,从而大大减小了出口点选择的工作量,提高了模拟范围与研究区域吻合的程度.该算法被成功应用到松辽流域,该区域西北面、北面、东面、东南通过国际界河和跨境河流与蒙、俄、朝三国相邻,南面比邻黄、渤海.     

试论地球运动与地质灾害及自然灾害系统

各种地质灾害与自然灾害不是孤立出现的,而是构成相互联系的灾害系统。灾害系统受控于地球的运动与天体活动。现在地球的运动已进入一个新的活跃时期,推测灾害有加剧的趋势,因此研究灾害系统的规律,制定灾害预测和防御措施是一项重要的工作。     

新疆哈密五堡乡缺水地区找水经验

通过在新疆哈密五堡乡南大草滩严重缺水地区的水地质勘察，找到了一个日供水量为3000m^3/d的小型水源地，为在同类地区找水提供了一定的找水经验。     

Evaluate the performance of an accelerated initial stiffness method in three dimensional finite element analysis

Newton’s method is a commonly used algorithm for elasto-plastic finite element analysis and has three common variations: the full Newton–Raphson method, the modified Newton–Raphson method and the initial stiffness method. The Newton–Raphson methods can converge to the solution in a small number of iterations when the system is stable; however, the methods can be quite computationally expensive in some types of problems, for example where the tangent stiffness matrix is unsymmetric or the plasticity is highly localized. The initial stiffness method is robust in those cases but requires a larger number of iterations. This prompted the formulation of many acceleration techniques in literature. In this paper, those techniques will be briefly discussed. This will be followed by the development of a modified acceleration technique for the initial stiffness method. The performance of the modified accelerated initial stiffness method will be examined in elasto-plastic analyses, using both direct and iterative matrix solvers. The results will be compared – in terms of the required number of iterations and the computation time – with an existing accelerated initial stiffness method, the non-accelerated initial stiffness method and the Newton–Raphson tangent stiffness method.     

海洋沉积物有机碳和稳定氮同位素分析的前处理影响

海洋沉积物中的有机碳和稳定氮同位素为海洋古环境和碳氮循环提供了大量信息,然而不同的前处理方法对有机碳和稳定氮同位素测定结果的准确性产生不同程度的影响.笔者通过大量条件实验,分析了前处理过程中影响结果准确性的可能因素.①器皿材质:使用聚丙烯和玻璃离心管进行酸处理所得样品的δ13C和δ15N基本无差别.②干燥方式:样品经热烘干燥会导致样品中轻碳组分和易挥发组分的逸散,引起样品中δ13C的分馏.鲜样和酸处理后样均采用热烘干燥会引起样品中δ15N发生明显分馏.③驱酸方式和洗酸程度:水洗造成溶解性有机碳和氮的损失,致使δ13C和δ15N值较真实值偏正,但酸蒸法不能保证氯离子的有效驱除.洗至中性后的洗酸次数对δ13C影响甚小,但会导致δ15N继续偏正.全程采用冷冻干燥,选用PP离心管作为主要酸处理水洗和干燥的器皿,具有很好的重复性,可获得较理想、准确的δ13C和δ15N测试数值.