A simple conceptual model for predicting the dissolution of phosphate rock in soils

Laboratory experimental and literature data were integrated to develop a simple, conceptual model to describe and predict the dissolution of a reactive phosphate rock (Gafsa phosphate rock, GPR) in soils. The model showed that initial solution Ca concentration strongly influences the time required for a single application of GPR (at 30 kgP ha^?1) to dissolve. The model predicts that all of the GPR will dissolve within a year of application in an unlimed, acid (pH_w 4.5) loam. However, if the soil has previously been limed to (pH_w 5.8, and contains permanent charge only, the model predicts that only about 50% of the GPR would have dissolved by the end of the second year after application. On the other hand, if a previously limed soil ((pH_w 5.8) contains variable-charge components, the model predicts that virtually all of the GPR would have dissolved in this soil by the end of the second year after application. These results emphasise that, even in the presence of a high proton supply, solution Ca has an overriding influence on the dissolution of GPR. The faster rate of GPR dissolution in the limed soil with variable charge, compared to that in the limed soil with permanent charge only, demonstrates the ability of the variable-charge component of soil to act as a sink for some of the lime-derived Ca. According to the solubility product principle, this allows more GPR to dissolve. Because of the generally stronger buffering of soil for P than for Ca, a relatively large proportion of any P removed by leaching and plant uptake is buffered by the sorbed phase. Consequently, the influence of leaching and plant uptake on GPR dissolution is attributed primarily to the removal of the relatively less-strongly buffered Ca.     

AHMED experiments on hygroscopic and inert aerosol behaviour in LWR containment conditions: experimental results

Hygroscopic NaOH, CsI, CsOH and inert Ag aerosol behaviour at different temperatures and relative humidities (RH) has been studied in a well instrumented and controlled vessel of 1.81 m³ total free volume. Homogeneous thermal-hydraulic conditions for aerosol measurement in the vessel were achieved. The aerosol number and mass concentration were measured continuously during the experiments using a Condensation Nucleus Counter and a Tapered Element Oscillating Microbalance. The particle size distribution and chemical composition in the test conditions were measured by Berner low pressure impactors. In the case of NaOH the half life of the aerosol mass concentration was more than four times longer at low RH (22%) as compared to high RH (96%). The half lives of the CsOH and CsI aerosols were only twice as long at low RH as compared to high RH. Thus at high RH (96–97%) the half lives of CsOH and CsI were twice as long as the half life for the NaOH aerosol. The faster decay of the NaOH aerosol is due to the smaller density decrease of NaOH during water condensation. CsOH particles grew rapidly to their equilibrium size at all humidities. The measured equilibrium size for CsOH aerosol agree well with the calculated particle size at different RHs. Experimental results were also compared with calculations obtained by severe accident computer codes. These calculated results will be presented in a later paper.     

勘测关键技术及其综合应用研究

勘测关键技术及其综合应用研究，系国家“八五”科技攻关２０８－０２－０５专题。该专题研究结合锦屏一、二级等工程，专业面广，应用性强，研究工作难度大，是当前水电工程地质勘探技术中的薄弱环节，是关系到前期工作进展和工程经济效益的重大课题。其研究内容包括：岩心定向技术、砂卵石层取心技术，地应力测试与分析新技术，岩体裂隙结构面的计算机处理系统、岩溶探测新技术、高分辨率工程地震勘探技术、３０００系列测井仪的改     

裂隙岩体中掏槽爆破的影响因素分析

对裂隙岩体中掏糟爆破布孔的影响因素进行了研究，并根据裂分布的情况提出相应的布孔方法和原则。对有关的工程施工具有实际意义。     

鄂尔多斯盆地含油气系统

鄂尔多斯盆地含油气系统研究目前尚无成熟的划分方案和系统成果,本文主要依据油气赋存的层位并参考油气源将其划分为下古生界含气系统、上古生界含气系统及中生界含油气系统。各含油(气)系统平面分布范围主要受生油岩、储集岩分布和油气运移方向的控制;其中,下古生界含气系统、中生界含油气系统主要分布于盆地中部。上古生界含气系统主要分布于盆地北部。     

盖层封闭能力的灰聚类评价方法

提出灰聚类评价方法，用于盖层封闭能力定量评价。所有被评价对象构成聚类对象集，所有评价指标构成评价指标集，所划分的盖层封闭能力等级构成聚类的灰类集，按照最大聚类权确定对象所属的灰类，即盖层的封闭能力级别。评价流程是：确定指标灰类模式→数据预处理→利用聚类公式计算→利用最大聚类权准则抉择。这种方法避免了加法评分法要依靠人的主观经验划定总评分值的问题，而且由于把评价对象视为“灰”的，具有处理边缘信息的能力。以琼东南盆地３个主要探区的盖层封闭性评价为例，介绍了灰聚类评价的具体应用方法。灰聚类评价方法同样可用于储集层评价、圈闭评价等地质问题的定量研究。表２参３（王孝陵摘     

块状岩体台阶爆破炮孔填塞作用的研究

本文利用电磁测量法及高速摄影法对块状模型中炮孔填塞物在孔内的运动规律和块体移动过程进行了研究。根据模拟试验及一些生产爆破的观测结果，对炮孔填塞机理提出了一些新的观点；同时就露天矿台阶爆破炮孔填塞长度及材料对爆破效果的影响作了简要分析。     

海南福山凹陷地层可钻性及钻头选型

利用测井资料及室内实验建立的可钻性模型编制了计算机软件，用其建立了海南福山凹陷地层连续可钻性剖面，并推荐出钻头选型，和现场实钻情况相当的吻合，为钻头合理选型提供了依据。     

节理岩体参数对围岩破损区影响的敏感性分析

本文针对黄河拉西瓦地下水电站工程，对节理岩体诸参数对围岩破损区范围的影响进行了敏感性分析。指出了主要敏感参数，对这些参数影响围岩破损区的趋势和可能程度进行了讨论，并对勘察和施工提出了一些意见。     

松软矿体有底柱高分段崩落法的改进方案

锦屏磷矿对其东山采区松软矿体所使用的分段崩落法做了集中快速采准施工、增加分段高度、实行水平或上向扇形深孔连续崩矿等改进,简化了采场结构,矿石损失率由原来的63％下降到改进后的20.34％,贫化率由23.92％下降到15.10％。