水压法评价混凝土渗透性的适用性研究

本文应用透水法、改进快速Cl-渗透法测定了不同强度等级、不同配合比混凝土试件的渗透性。结果表明透水法未考虑实际工程中混凝土所受的约束作用,其适用性对强度等级的依赖性很强。

混凝土渗透性测定方法比较与选择

应用透水法、改进快速Cl-渗透法及CH2Cl2浸泡法测定了不同强度等级、不同配合比混凝土试件的渗透性。试验结果表明,透水法未考虑实际工程中混凝土所受的约束作用,其适用性对强度等级的依赖性很强;而改进快速Cl-渗透法和CH2Cl2浸泡法避免了上述缺点,且二者得到的混凝土渗透性结果具有较好的相关性。

混凝土渗透性测试方法的相关性研究

抗水渗透法、RCM法和电通量法是从不同角度反映混凝土密实性的测试方法,研究这些测试指标的相关性对于科学、合理选择设计参数具有重要意义。研究分别采用抗水渗透法、RCM法和电通量法测试C20~C60强度等级混凝土的渗透性,并考虑了不同含气量和不同粉煤灰掺量的影响,分析了3种渗透性测试方法之间的相关性。结果表明：对于大掺量粉煤灰混凝土,RCM法和渗水高度法的相关性较差,RCM法与电通量法则具有较好的线性相关性。

三维动边界破开算子法不恒定流模拟研究

本文以静水压强假定下的大尺度三维水流方程为基础，对微分方程采用混合破开算子法求解，并引入了透水介质法处理动水边界、自由水面边界和床底边界，将动边界问题转化为定边界问题求解，对大尺度水体中的恒定与非恒定流动进行了成功的模拟计算．

天津市建成区雨水排放费分区核算研究

国外实践证明雨水排放费征收是缓解城市内涝和面源污染的有效经济机制,首要环节是围绕控制降雨径流确定科学合理的城市雨水排放费率.当前国内雨水排放费征收尚处于探索阶段,探讨按照城市土地利用类型分区征收雨水排放费具有重要的实践意义.核算从宏观和微观两个角度切入,采用费率因子法和不透水面积百分比法,以天津市建成区为例分别构建了雨水排放费征收适用参数和标准,分别核算并对结果相互验证.两种方法核算结果基本相符,其中工业用地和居住用地采用不透水面积百分比法均略大于费率因子法,而商业用地费率因子法多于不透水面积百分比法.针对雨水排放费敏感性设计了包含不同土地利用类型变量的4个方案,结果表明,工业用地、居住用地、交通用地、商业用地应是未来雨水排放费的主要承担者.

Timing of advanced water flooding in low permeability reservoirs

It is very important to design the optimum starting time of water injection for the development of low permeability reservoirs. In this type of reservoir the starting time of water injection will be affected by a reservoir pressure-sensitive effect. In order to optimize the starting time of water injection in low permeability reservoirs, this effect of pressure change on rock permeability of low permeability reservoirs was, at first, studied by physical simulation. It was shown that the rock permeability decreases exponentially with an increase in formation pressure. Secondly, we conducted a reservoir engineering study, from which we obtained analytic relationships between formation pressure, oil production rate, water production rate and water injection rate. After our physical, theoretical and economical analyses, we proposed an approach which takes the pressure-sensitive effect into consideration and designed the optimum starting time of water injection, based on the principle of material balance. Finally, the corresponding software was developed and applied to one block of the Jiangsu Oilfield. It is shown that water injection, in advance of production, can decrease the adverse impact of the pressure-sensitive effect on low permeability reservoir development. A water-flooding project should be preferably initiated in advance of production for no more than one year and the optimum ratio of formation pressure to initial formation pressure should be maintained at a level between 1.05 and 1.2.

Membrane Engineering for Green Process Engineering

Green process engineering, which is based on the principles of the process intensification strategy, can provide an important contribution toward achieving industrial sustainable development. Green process engineering refers to innovative equipment and process methods that are expected to bring about substan- tial improvements in chemical and any other manufacturing and processing aspects. It includes decreasing production costs, equipment size, energy consumption, and waste generation, and improving remote con- trol, information fluxes, and process flexibility. Membrane-based technology assists in the pursuit of these principles, and the potential of membrane operations has been widely recognized in the last few years. This work starts by presenting an overview of the membrane operations that are utilized in water treatment and in the production of energy and raw materials. Next, it describes the potential advantages of innovative membrane-based integrated systems. A case study on an integrated membrane system （IMS） for seawa- ter desalination coupled with raw materials production is presented. The aim of this work is to show how membrane systems can contribute to the realization of the goals of zero liquid discharge （ZLD）, total raw materials utilization, and low energy consumption.

Improved designed method of pervious concrete based on optimal volume ratio of paste to aggregate

An improved design method of pervious concrete was proposed to lower the deviation between the designed and actual porosity and maintain both mechanical property and permeability of pervious concrete. The improved design method is mainly based on the optimal volume ratio of paste to aggregate(VRPA), which was determined by testing the average thickness of cement paste coating aggregate. The performances of pervious concrete designed by the traditional method and the improved one were compared. The results show that with the increase of designed porosity, the reduction of compressive strength and flexural strength of pervious concrete designed by the improved method is significantly smaller than those designed by the traditional one. The maximum deviation between the designed and actual porosity of the pervious concrete by the improved method is only 1.54%, which is far less than 8.7% obtained by the traditional one. Micro-structural analysis shows that the porous distribution of pervious concrete designed by improved method exhibits better uniformity.

Wastewater Treatment of a Cardboard Manufacturing Plant by Infiltration Percolation

Different coastal sands of the city of El Jadida are used to filter wastewater from a cardboard manufacturing plant combined with fly ash and bottom ash （by-products of a local power plant）. The performances of five matrices of these elements are compared in infiltration-percolation in vertical columns. The study of particle size sand is performed beforehand. The chemical and mineralogical composition of fly ash and bottom ash are produced by X-ray fluorescence and X-ray diffraction respectively. The wastewater samples were collected during a complete cycle of production of the cardboard. The heavy metals content before and after filtration was obtained by atomic emission spectrometry with inductively coupled plasma （ICP-AES）. The parameters analyzed were： total suspended solids （TSS）, organic matter COD, BODs, the potential hydrogen pH and heavy metals （iron, zinc and arsenic）. The results are very conclusive and respect the essence of control required by Moroccan regulations （law 1606-06） related to discharges from the papermaking and cardboard industry.

Integrating CART Algorithm and Multi-source Remote Sensing Data to Estimate Sub-pixel Impervious Surface Coverage:A Case Study from Beijing Municipality,China

The sub-pixel impervious surface percentage(SPIS) is the fraction of impervious surface area in one pixel,and it is an important indicator of urbanization.Using remote sensing data,the spatial distribution of SPIS values over large areas can be extracted,and these data are significant for studies of urban climate,environment and hydrology.To develop a stabilized,multi-temporal SPIS estimation method suitable for typical temperate semi-arid climate zones with distinct seasons,an optimal model for estimating SPIS values within Beijing Municipality was built that is based on the classification and regression tree(CART) algorithm.First,models with different input variables for SPIS estimation were built by integrating multi-source remote sensing data with other auxiliary data.The optimal model was selected through the analysis and comparison of the assessed accuracy of these models.Subsequently,multi-temporal SPIS mapping was carried out based on the optimal model.The results are as follows:1) multi-seasonal images and nighttime light(NTL) data are the optimal input variables for SPIS estimation within Beijing Municipality,where the intra-annual variability in vegetation is distinct.The different spectral characteristics in the cultivated land caused by the different farming characteristics and vegetation phenology can be detected by the multi-seasonal images effectively.NLT data can effectively reduce the misestimation caused by the spectral similarity between bare land and impervious surfaces.After testing,the SPIS modeling correlation coefficient(r) is approximately 0.86,the average error(AE) is approximately 12.8%,and the relative error(RE) is approximately 0.39.2) The SPIS results have been divided into areas with high-density impervious cover(70%–100%),medium-density impervious cover(40%–70%),low-density impervious cover(10%–40%) and natural cover(0%–10%).The SPIS model performed better in estimating values for high-density urban areas than other categories.3) Multi-temporal SPIS mapping(1991–2016) was conducted based on the optimized SPIS results for 2005.After testing,AE ranges from 12.7% to 15.2%,RE ranges from 0.39 to 0.46,and r ranges from 0.81 to 0.86.It is demonstrated that the proposed approach for estimating sub-pixel level impervious surface by integrating the CART algorithm and multi-source remote sensing data is feasible and suitable for multi-temporal SPIS mapping of areas with distinct intra-annual variability in vegetation.

Tumor necrosis factor alpha increases intestinal permeability in mice with fulminant hepatic failure

AIM:To determine the effect of tumor necrosis factor alpha(TNF-α) on intestinal permeability(IP) in mice with fulminant hepatic failure(FHF),and the expression of tight junction proteins.METHODS:We selected D-lactate as an index of IP,induced FHF using D-galactosamine/lipopolysaccharide and D-galactosamine/TNF-α,assessed the results using an enzymatic-spectrophotometric method,transmission electron microscopy,immunohistochemistry,Western blotting and real-time quantitative polymerase chain reaction.The effect of the administration of antiTNF-α immunoglobulin G(IgG) antibody,before the administration of D-galactosamine/lipopolysaccharide,on TNF-α was also assessed.RESULTS:IP was significantly increased in the mouse model of FHF 6 h after injection(13.57 ± 1.70 mg/L,13.02 ± 1.97 mg/L vs 3.76 ± 0.67 mg/L,P = 0.001).Electron microscopic analysis revealed tight junction(TJ) disruptions,epithelial cell swelling,and atrophy of intestinal villi.Expression of occludin and claudin-1 mRNA was significantly decreased in both FHF models(occludin:0.57 ± 0.159 fold vs baseline,P = 0.000;claudin-1:0.3067 ± 0.1291 fold vs baseline,P = 0.003),as were the distribution density of proteins in the intestinal mucosa and the levels of occludin and claudin-1 protein(occludin:0.61 ± 0.0473 fold vs baseline,P = 0.000;claudin-1:0.6633 ± 0.0328 fold vs baseline,P = 0.000).Prophylactic treatment with antiTNF-α IgG antibody prevented changes in IP(4.50 ± 0.97 mg/L vs 3.76 ± 0.67 mg/L,P = 0.791),intestinal tissue ultrastructure,and the mRNA levels of occludin and claudin-1 expression(occludin:0.8865 ± 0.0274 fold vs baseline,P = 0.505;claudin-1:0.85 ± 0.1437 fold vs baseline,P = 0.1),and in the protein levels(occludin:0.9467 ± 0.0285 fold vs baseline,P > 0.05;claudin-1:0.9533 ± 0.0186 fold vs baseline,P = 0.148).CONCLUSION:Increased in IP stemmed from the downregulation of the TJ proteins occludin and claudin-1,and destruction of the TJ in the colon,which were induced by TNF-α in FHF mice.

Optimization of Osmotic Dehydration of Medlars Slices in Sucrose Solution Using Response Surface Methodology

Response surface methodology, according to CCD （central composite design）, was used to determine the optimum processing conditions giving maximum water loss and minimum solid gain during osmotic dehydration of medlars in sucrose solution. The independent variables of osmotic dehydration were temperature （25-65 ℃）, processing time （20-240 min）, sugar concentration （45%-65% w/w） and blanching time （0-180 s）. The optimum conditions were found to be： temperature = 55 ℃, time = 180 min, concentration = 60° Brix and blanching time = 30 s. At this optimum point, water loss, weight reduction and solid gain were found to be 74.12% and 7.136%, respectively.

Other Seawater Desalination Method

This method of desalination is based as the previous one, i.e. It applies the possibilities of the laws of inorganic chemistry precisely the laws of the precipitation to desalinate any water containing salt, with priority for seawater the most abundant source of water on our planet. It is good to remember that the industry always has used these laws for the preparation of certain compounds. As the above method, rather than consume energy such as reverse osmosis, distillation, electrodialysis, it requires no energy. On the contrary recycling products used delivers power.

Optimized water vapor permeability of sodium alginate films using response surface methodology

The water vapor permeability （WVP） of films is important when developing pharmaceutical applications. Films are frequently used as coatings, and as such directly influence the quality of the medicine. The optimization of processing conditions for sodium alginate films was investigated using response surface methodology. Single-factor tests and Box-Behnken experimental design were employed. WVP was selected as the response variable, and the operating parameters for the single-factor tests were sodium alginate concentration, carboxymethyl cellulose （CMC） concentration and CaClz solution immersion time. The coefficient of determination （R2） was 0.97, indicating statistical significance. A minimal WVP of 0.389 8 g-mm/（m^2.h.kPa） was achieved under the optimum conditions. These were found to be a sodium alginate concentration, CMC concentration and CaCl2 solution immersion time at 8.04%, 0.13%, and 12 min, respectively. This provides a reference for potential applications in manufacturing film-coated hard capsule shells.

Preparation of microsized single-crystalline Co_3O_4 by high-temperature hydrolysis

Microsized single-crystalline Co3O4 has been synthesized by high-temperature hydrolysis of CoCD2H20 at 600℃. The samples were characterized by powder X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results reveal that the as-prepared powders are microsized single-crystalline CO3O4 with cubic spinel structure. An increase in the high-temperature hydrolysis time results in the evolution of particle shapes from cube to quasi-sphere, and then to octahedron. The effect of NaCl additive on the surface morphologies of Co3O4 particles was experimentally investigated. The results indicate that the NaCl additive acts as an inert disperse phase in the high-temperature hydrolysis, and prevents the aggregation of Co3O4 particles effectively.

Definition of the general initial water penetration fracture criterion for concrete and its engineering application

A general initial water penetration(seepage) fracture criterion for concrete is proposed to predict whether or not harmful water penetration(hydraulic fracturing),other than microcracking,will occur in concrete structures in a severe high water pressure environment.The final regression,of the different macroscopic failure types in concrete to microscopic ModeⅠ c racking,allows the use of only one universal criterion to indicate the damage.Thus,a general initial water penetration fracture criterion is approximately defined as a strain magnitude of 1000×10-6,based on the concept of tensile strain derived from experimental results in the relevant literature.Then,the locations of harmful water penetration fracture(hydraulic fracture) in the high arch dam mass of the Jinping first class hydropower project are analyzed using the nonlinear finite element method(FEM) according to the proposed criterion.The proposed criterion also holds promise for other concrete structures in high water pressure environments.

Bench-top aqueous two-phase extraction of isolated individual single-walled carbon nanotubes

Isolation and purification of single-walled carbon nanotubes （SWCNTs） are prerequisites for their implementation in various applications. In this work, we present a fast （-5 min）, low-cost, and easily scalable bench-top approach to the extraction of high-quality isolated SWCNTs from bundles and impurities in an aqueous dispersion. The extraction procedure, based on aqueous two-phase （ATP） separation, is widely applicable to any SWCNT source （tested on samples up to 1.7 nm in diameter） and independent of defect density, purity, diameter, and length. The extracted dispersions demonstrate that the removal of large aggregates, small bundles, and impurities is comparable to that by density gradient ultracentrifugation, but without the need for high-end instrumentation. Raman and fluorescence-excitation spectroscopy, single-nanotube fluorescence imaging, atomic force and transmission electron microscopy, and thermogravimetric analysis all confirm the high purity of the isolated SWCNTs. By predispersing the SWCNTs without sonication （only gentle stirring）, full-length, pristine SWCNTs can be isolated （tested up to 20 μm）. Hence, this simple ATP method will find immediate application in the generation of SWCNT materials for all levels of nanotube research and applications, from fundamental studies to high-performance devices.