Filtration and Clogging Behavior of Geotextiles with Roorkee Soils

Geotextile filters are rapidly replacing graded granular filters as the standard of practice in geotechnical design. The objective of the present study is to predict the behavior of the geotextile filter for the locally (Roorkee—India) available soils using three different geotextiles (two nonwoven and one woven). Nonwoven geotextiles are commonly used in filtration applications. This paper evaluates the long-term performance of two needle-punched nonwoven geotextiles and one woven geotextile. Filtration tests on soil–geotextile filter systems were conducted in the laboratory in order to evaluate the filtration and clogging behavior. Laboratory test program, include evaluation of performance of two different nonwoven and one woven geotextile filters in combination with locally available Solani River Sand and Clayey Soil. The paper describes the concept and details of the Fine Fraction Filtration (F³) test and presents data on three different geotextiles, which were evaluated using three different soil types. It is deduced that in all filtration applications, the non-woven geotextile would perform better than the woven geotextile.     

龙须菜和扁江篱多糖的组成及其抗肿瘤效果

于１９８５－１９８７年期间用冷水和热水对采集于青岛的龙须菜和扁江篱的琼胶型多糖进行提取。两海藻的热水提取多糖都通过ＤＥＡＥ－ＳｅｐｈａｄｅｘＡ５０色谱桩用热水和不同浓度ＮａＣｌ深液前后进行洗脱分级。龙须菜和扁江篱多糖的主要级分分别为０．５ｍｏｌ／Ｌ和１．０ｍｏｌ／ＬＮａＣｌ洗脱级分。对各级分做化学分析及ＩＲ和＾１３ＣＮＭＲ光谱分析。结果表明，龙须菜多糖由琼二糖、琼胶糖前体和６－ＯＣＨ３－琼二糖组成     

华南区域高分辨率数值模式前汛期预报初步评估

基于华南地区自动站逐小时观测资料, 采用传统站点评分、邻域法等评估华南区域高分辨率数值模式(包括GRAPES_GZ_R 1 km模式和GRAPES_GZ 3 km模式)对降水、地面温度和风场等要素的预报能力。结果表明: GRAPES_GZ_R 1 km模式的降水预报技巧优于GRAPES_GZ 3 km模式, 模式预报以正偏差为主。对于不同起报时间的预报, 00时(世界时, 下同)起报的预报效果优于12时。GRAPES_GZ_R 1 km模式的TS评分是GRAPES_GZ 3 km模式的两倍以上, 对不同降水阈值的评分均较高。分数技巧评分(FSS)显示GRAPES_GZ_R 1 km模式6 h累计降水预报在0.1 mm、1 mm及5 mm以上的降水均可达到最低预报技巧尺度, 对所检验降水对象的空间位置把握能力更好。2 m气温和10 m风速检验结果表明两个模式均能较好把握广东省温度的分布特征, GRAPES_GZ_R 1 km模式对2 m气温预报结果优于GRAPES_GZ 3 km模式, 预报绝对误差更小; 两个模式对风速的预报整体偏强, 预报偏差在1~4 m/s之间, 但相比之下GRAPES_GZ 3 km模式在风场预报上表现更好。GRAPES_GZ_R 1 km模式的2 m气温和10 m风速预报偏差随降水过程存在明显波动, 强降水过后温度预报整体偏低, 风速预报偏强, 在模式产品订正、使用等需要考虑模式对主要天气系统的预报情况。总的来说, GRAPES_GZ_R 1 km模式的预报产品具有较好的参考价值。      

A CRPS-Based Spatial Technique for the Verification of Ensemble Precipitation Forecasts

Traditional precipitation skill scores are affected by the well-known“double penalty”problem caused by the slight spatial or temporal mismatches between forecasts and observations. The fuzzy (neighborhood) method has been proposed for deterministic simulations and shown some ability to solve this problem. The increasing resolution of ensemble forecasts of precipitation means that they now have similar problems as deterministic forecasts. We developed an ensemble precipitation verification skill score, i.e., the Spatial Continuous Ranked Probability Score (SCRPS), and used it to extend spatial verification from deterministic into ensemble forecasts. The SCRPS is a spatial technique based on the Continuous Ranked Probability Score (CRPS) and the fuzzy method. A fast binomial random variation generator was used to obtain random indexes based on the climatological mean observed frequency, which were then used in the reference score to calculate the skill score of the SCRPS. The verification results obtained using daily forecast products from the ECMWF ensemble forecasts and quantitative precipitation estimation products from the OPERA datasets during June-August 2018 shows that the spatial score is not affected by the number of ensemble forecast members and that a consistent assessment can be obtained. The score can reflect the performance of ensemble forecasts in modeling precipitation and thus can be widely used.     

用超速CT机检测99例无症状香港中国人降低钙指数

回顾分析Ｍａｔｉｌｄａ医院超速ＣＴ室筛选首批病人中９９例中国人资料，很明显从通常采用１３０－１００Ｈｏｕｎｓｆｉｅｌｄ单位作为检出冠状血管钙化的基数应用至中国人身上其阈值数目需要降低，同时，我们也发现如果病人年龄按每１０年范围分组（２１－３０，３０－４０，４１－５０，５１－６０）而计算其超速ＣＴ的钙化指数会较随机男女一起按平均计算更易区分其差异．进一步分析显示，男性中年时候超速ＣＴ指数已达最高值，而女性则晚１０年方达最高值，因此，为了更易探测冠脉循环内钙化倾向应作出超速ＣＴ检出钙化的指数数目．这些实践经验对动脉粥样硬化过程的预测或预防有实际意义．     

Effect of chemical fertilizers on the fractionation of Cu,Cr and Ni in contaminated soil

Effect of chemical fertilizers (urea, NH₄Cl, Ca(NO₃)₂, KCl and KH₂PO₄) on the fractionation of Cu, Cr and Ni was studied by a 4-month incubation experiment. Using sequential extraction procedure, it was found that the application of fertilizers could change the distribution of Cu, Cr and Ni in the fractions of soil. Applying urea (CO(NH₂)₂) significantly decreased the concentrations of Cu, Cr and Ni in water soluble plus exchangeable (WE) fraction, but increased those in Fe–Mn oxides bound (FM) fraction (p < 0.01). However, application of NH₄Cl caused an increase in the WE fraction by 27.7% for Cu, 111.5% for Cr and 20.4% for Ni. The CO(NH₂)₂ raised the soil pH from 4.51 to 4.96, whereas NH₄Cl lowered the pH of soil by 0.44 units. The WE fraction of the three heavy metals was significantly increased, while the FM fraction was significantly decreased by adding KCl (p < 0.01). Moreover, the supply of KH₂PO₄ reduced the WE and carbonate bound (CB) fractions of Cu, Cr and Ni in the soil, however, it raised Cu and Ni in the residual (RS) fraction and Cr in the FM fraction. In addition, the mobility index indicated that KCl and NH₄Cl increased the mobility of Cu, Cr and Ni in the soil, whereas urea and KH₂PO₄ decreased the mobility of the three metals in the soil. These results suggest that applying chemical fertilizers does not only provide plant nutrients, but may also change the speciation and mobility of heavy metals in the soil.     

强化《测量学》实践性教学的方法

介绍国家教委高等工程专科学校教学改革试点水资源与水文专业的《测量学》实践性教学改革成果，阐述了《测量学》实践性教学的考核内容，办法与评分标准以及在实践中取得效果。     

Modelling the Gross Primary Productivity of West Africa with the Regional Biomass Model RBM+, using optimized 250 m MODIS FPAR and fractional vegetation cover information

Global warming associated with climate change is one of the greatest challenges of today’s world. Increasing emissions of the greenhouse gas CO₂ are considered as a major contributing factor to global warming. One regulating factor of CO₂ exchange between atmosphere and land surface is vegetation. Measurements of land cover changes in combination with modelling the Gross Primary Productivity (GPP) can contribute to determine important sources and sinks of CO₂.The aim of this study is to accurately model the GPP for a region in West Africa with a spatial resolution of 250 m, and the differentiation of GPP based on woody and herbaceous vegetation. For this purpose, the Regional Biomass Model (RBM) was applied, which is based on a Light Use Efficiency (LUE) approach. The focus was on the spatial enhancement of the RBM from the original 1000–250 m spatial resolution (RBM+). The adaptation to the 250 m scale included the modification of two main input parameters: (1) the fraction of absorbed Photosynthetically Active Radiation (FPAR) based on the 1000 m MODIS MOD15A2 FPAR product which was downscaled to 250 m using MODIS NDVI time series; (2) the fractional cover of woody and herbaceous vegetation, which was improved by using a multi-scale approach. For validation and regional adjustments of GPP and the input parameters, in situ data from a climate station and eddy covariance measurements were integrated.The results of this approach show that the input parameters could be improved significantly: downscaling considerably reduces data gaps of the original FPAR product and the improved dataset differed less than 5.0% from the original data for cloud free regions. The RMSE of the fractional vegetation cover varied between 5.1 and 12.7%. Modelled GPP showed a slight overestimation in comparison to eddy covariance measurements. The in situ data was exceeded by 8.8% for 2005 and by 2.0% for 2006. The model results were converted to NPP and also agreed well with previous NPP measurements reported from different studies. Altogether a high accuracy and suitability of the regionally adjusted and downscaled model RBM+ can be concluded. The differentiation between vegetation growth forms allows a separation of long-term and short-term carbon storage based on woody and herbaceous vegetation, respectively.     

煤柱-顶板系统协同作用的脆性失稳与非线性演化机制

把坚硬顶板视为弹性梁,把煤柱视为应变软化介质并采用W e ibu ll分布描述它的损伤本构模型,本文对坚硬顶板和煤柱组成的力学系统,用突变理论方法研究了它的演化失稳过程。通过对建立的尖点突变模型的分析发现,系统失稳主要取决于系统的刚度比k与材料的均匀性或脆性指标m值,并给出了失稳的充要条件力学判据和失稳突跳量的表达式。考虑煤柱介质的粘性或蠕变性,建立了系统演化的非线性动力学模型物理预报模型,并给出了根据顶板沉降观测数据反演非线性动力学模型的方法和稳定性判别准则。对木城涧矿根据观测序列进行了动力学模型的反演分析,一个重要发现是:D值在临近失稳时陡增出现峰值而后急剧下降。根据材料损伤与声发射累计计数的对应关系,建立了系统演化过程中声发射率的动力学模型,并进行了声发射模拟分析和分维分析,发现m值与系统的演化路径对系统演化的声发射活动规律及分维特征有重要影响,单纯根据声发射监测和降维现象预报冲击地压是不可靠的。     

Deep-Sea Sediment Compression Curves: Some Controlling Factors,Spurious Overconsolidation,Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.