新颖高温液化水养生四小时快速推定水泥标号

此法思路新颖、科学、创新。把被测水泥试块放人予压自动恒温、恒压的加热容器内，经130℃液化水养生，达到快速稳定的增长强度，从而实现在最短的时间内确定出水泥标号，以利及时科学调整混凝土与砂浆施工配合比，确保建筑工程质量。文中介绍了测试操作方法和原理，并用实测数据，应用科学数理统计方法，推导出快速推定水泥标号计算式，非常适用于商品混凝土工厂和土建施工现场使用。

高温液化水养生快速推定水泥标号新法

文中介绍了测试操作过程和原理,并用实测数据、应用科学数理统计方法,推导出快速推定水泥标号计算式。试 块放入预先加压容器内,经过 130 ℃高温液化水养生,可快速稳定增长强度。在商品混凝土工厂和土建施工现 场使用,效果很好。

富水易液化砂层盾构始发施工技术探讨

盾构施工法是通过安装在刀盘上的刀具切削土体而使隧道一次成型的施工方法,因为高效率、高安全、高环保等优点,在水利、交通和采矿等领域得到了广泛的应用,但盾构始发属于施工风险源,很容易造成工程事故。本文结合南通地铁南—太区间盾构施工实例,通过对富水砂层中始发端头加固、洞门破除、洞门密封处理、反力架和始发架的安装、负环管片的安装和盾构的始发等相关关键技术的阐述,为此类地层的盾构始发施工提供参考。

富水易液化砂层盾构始发施工工艺

复杂地质条件下的隧道施工难度较大,且以盾构始发施工较为明显,易出现质量或安全层面的问题。通过对富水易液化砂层的盾构始发施工进行分析,阐述施工过程中端头加固、洞门破除、洞门密封装置设置、反力架、始发架安装的施工工艺及要点。多项控制措施的实施确保了施工质量,保证了施工安全。

涡轮排气液化循环发动机的能量分析

对涡轮排气液化循环发动机液化水的处置进行了研究。通过热力学分析获得了发动机性能的理论解,并利用热力计算进行验证。分析表明液态水直接排出发动机将导致约2%的比冲损失。分析了发动机各环节的能量传递,获得了燃烧室中心燃烧区焓增的理论表达式,可作为燃烧室性能的详细分析的基础。

含地下水的回填砂土重力式岸墙地震残余角位移的拟静力计算

引用液化度指标考虑含地下水的回填砂土地震过程中的超静孔隙水压力对墙体运动的影响,基于Mononobe-Okabe拟静力法修正考虑液化度的动主动土压力,根据静力水压力理论近似计算土颗粒里的动水压力。同时考虑了水平与竖向地震载荷,根据力矩极限平衡确定旋转门槛加速度系数,采用旋转块体方法计算岸墙主动旋转运动下的地震残余角位移。选用一理想的地震运动特征,应用该简单预测位移的方法对一算例进行了推算;并对回填砂土内摩擦角、墙体与土间摩擦角、水平与竖向地震加速度系数、回填土地下水位、墙前自由水位和码头墙宽高比多种参数下对旋转角位移的影响作了详细的定性分析,得出墙体残余角位移随着回填砂土液化度升高而逐渐增大,以及当液化度很高时土的内摩擦角和墙体的摩擦将不再起工程作用等有用结论。

Effect of inorganic salt impurities on seeded precipitation of silica hydrate from sodium silicate solution

To clarify the precipitation of silica hydrate from the real desilication solutions of aluminosilicate solid wastes by adding seeds and improve integrated waste utilization,the seeded precipitation was studied using synthesized sodium silicate solution containing different inorganic salt impurities.The results show that sodium chloride,sodium sulfate,sodium carbonate,or calcium chloride can change the siloxy group structure.The number of high-polymeric siloxy groups decreases with increasing sodium chloride or sodium sulfate concentration,which is detrimental to seeded precipitation.Calcium chloride favors the polymerization of silicate ions,and even the chain groups precipitate with the precipitation of high-polymeric sheet and cage-like siloxy groups.The introduced sodium cations in sodium carbonate render a more open network structure of high-polymeric siloxy groups,although the carbonate ions favor the polymerization of siloxy groups.No matter how the four impurities affect the siloxy group structure,the precipitates are always amorphous opal-A silica hydrate.

Discussion on storm-induced liquefaction of the superficial stratum in the Yellow River subaqueous delta

Geological disasters on the superficial seafloor were revealed in geological investigation on the Yellow River subaqueous delta. Combined with dynamic triaxial tests and wave flume experiments, occurring conditions and forming patterns of liquefaction as well as motion of the liquefied soil were explained in this paper. Based on the viewpoint that the geological disasters were formed due to silty soil liquefaction under storm waves, re-stratification issue of the superficial stratum was analyzed. Movement of the liquefied soil agreed with the wave, leading to differentiation of the soil particles. Research issues in respect of geological, environment and engineering of storm-induced liquefaction were also discussed.

Allelopathy Effect of Wheat Root Aqueous Extracts on Different Vigna angularis Varieties

Objective] This study aimed to investigate the al elopathy effect on the seed germination and seedling growth of different adzuki bean （Vigna angularis） vari-eties in wheat root aqueous extracts. [Method] Culture dish method and pot experi-ment were carried out with the seeds and the seedling of 10 adzuki bean varieties, respectively, and seed germination rate and various indexes of the seedlings were measured. [Result] ① 30 g/L wheat root aqueous extracts very significantly im-proved the germination rate and sprouting index of B1789, Baihong 3, Baohong 947. ② The genotype differences of adzuki bean seedling was presented by the morphological index in wheat root aqueous extracts treatment; among al the mor-phological indexes, Baohong 947, Jinhong 3 presented a positive al elopathic effect, and their plant height, root length and leaf area were extremely significantly in-creased, while the fresh weights of both above-ground and underground parts were increased obviously, compared with the control. ③ According to the synthetical al-lelopathic indices, wheat root aqueous extracts had different degrees of promoting effects on the six adzuki bean varieties： Baohong 947〉Baihong 6〉B1789〉Zunhua-hong〉Jihong〉Jinhong 3〉Baohong 8824-17〉Baihong 3. ④ Treated by wheat root aqueous extract, the SOD activity, POD activity, MDA content, TTC activity and chlorophyl content in the seedlings of adzuki beans of different genotypes changed by a smal er range in al elopathic promotion varieties than in al elopathic inhibition varieties. [Conclusion] The results proved that Baohong 947 is the best summer-planting variety after wheat.

Solvatochromic Parameters and Preferential Solvation Behavior for Binary Mixtures of 1,3-Dialkylimidazolium Ionic Liquids with Water

Binary mixtures of 1,3-dialkylimidazolium based ionic liquids （ILs） and water were selected as solvent systems to investigate the solute-solvent and solvent-solvent interactions on the preferential solvation of solvatochromic indicators at 25 ℃. Empirical solvatochromic pa- rameters, dipolarity/polarizability （π^＊）, hydrogen-bond donor acidity （α）, hydrogen-bond acceptor basicity （β）, and Reichardt＇s polarity parameters （ET^N） were measured from the ultraviolet-visible spectral shifts of 4-nitroaniline, 4-nitroanisole, and Reichardt＇s dye. The solvent properties of the IL-water mixtures were found to be influenced by IL type and IL mole fraction （XIL）. All these studied systems showed the non-ideal behavior. The max- imum deviation to ideality for the solvatochromic parameters can be obtained in the XIL range from 0.i to 0.3. For most of the binary mixtures, the π^＊ values showed the synergistic effects instead of the ETN, α and β values. The observed synergy extent was dependent on the studied systems, such as the dye indicator and IL type. A preferential solvation model was utilized to gather information on the molecular interactions in the mixtures. The dye indicator was preferentially solvated on the following trend： IL〉IL-water complex〉water.

Ion Product of Pure Water Characterized by Physics-Based Water Model

Pure water has been characterized for nearly a century, by its dissociation into hydronium （H3O）1＋ and hydroxide （HO）1- ions. As a chemical equilibrium reaction, the equilibrium constant, known as the ion product or the product of the equilibrium concentration of the two ion species, has been extensively measured by chemists over the liquid water temperature and pressure range. The experimental data have been nonlinear least-squares fitted to chemical thermodynamic-based equilibrium equations, which have been accepted as the industrial standard for 35 years. In this study, a new and statistical-physics-based water ion product equation is presented, in which, the ions are the positively charged protons and the negatively charged proton-holes or prohols. Nonlinear least squares fits of our equation to the experimental data in the 0-100℃ pure liquid water range, give a factor of two better precision than the 35-year industrial standard.

Effects of reaction parameters on preparation of Cu nanoparticles via aqueous solution reduction method with NaBH_4

The preparation of Cu nanoparticles by the aqueous solution reduction method was investigated. The effects of different reaction parameters on the preparation of Cu nanoparticles were studied. The optimum conditions for preparing well-dispersed nanoparticles were found as follows: 0.4 mol/L NaBH4 was added into solution containing 0.2 mol/L Cu2+, 1.0% gelatin dispersant in mass fraction, and 1.2 mol/L NH3?H2O at pH 12 and 313 K. In addition, a series of experiments were performed to discover the reaction process. NH3?H2O was found to be able to modulate the reaction process. At pH=10, Cu2+ was transformed to Cu(NH3)42+ as precursor after the addition of NH3?H2O, and then Cu(NH3)42+ was reduced by NaBH4 solution. At pH=12, Cu2+ was transformed to Cu(OH)2 as precursor after the addition of NH3?H2O, and Cu(OH)2 was then reduced by NaBH4 solution.

Effects of Main Parameters on Rheological Properties of Oil-Coal Slurry

Oil-coal slurry prepared in coal direct liquefaction is a dispersed solid-liquid suspension system. In this paper, some factors such as solvent properties, solid concentrations and temperatures, which affect viscosity change of oil-coal slurry, were studied. The viscosity of coal slurry was measured using rotary viscometer, and the rheological properties have been investigated. The viscosity and rheological curves were plotted and regressed, respectively. The results show that the coal slurry behaves a pseudoplastic and thixotropic property. The rheological type of coal slurry was ascertained and its rheological equations were educed. The oil-coal slurry changes to non-Newtonian fluid from Newtonian fluid with the increasing of solid concentration.

Distribution and transformation behaviors of heavy metals during liquefaction process of sewage sludge in ethanol-water mixed solvents

Liquefaction of sewage sludge(SS)in ethanol-water cosolvents is a promising process for the preparation of bio-oil/biochar products.Effect of the combined use of ethanol and water on the distribution/transformation behaviors of heavy metals(HMs)contained in raw SS is a key issue on the safety and cleanness of above liquefaction process,which is explored in this study.The results show that pure ethanol facilitates the migration of HMs into biochar products.Pure water yields lower percentages of HMs in mobile/bioavailable speciation.Compared with sole solvent treatment,ethanol-water cosolvent causes a random/average effect on the distribution/transformation behaviors of HMs.After liquefaction of SS in pure water,the contamination degree of HMs is mitigated from high level(25.8(contamination factor))in raw SS to considerable grade(13.4)in biochar and the ecological risk is mitigated from moderate risk(164.5(risk index))to low risk(78.8).Liquefaction of SS in pure ethanol makes no difference to the pollution characteristics of HMs.The combined use of ethanol and water presents similar immobilization effects on HMs to pure water treatment.The contamination factor and risk index of HMs in biochars obtained in ethanol-water cosolvent treatment are 13.1-14.6(considerable grade)and 79.3-101.0(low risk),respectively.In order to further control the pollution of HMs,it is preferentially suggested to improve the liquefaction process of SS in ethanol-water mixed solvents by introducing conventional lignocellulosic/algal biomass,also known as co-liquefaction treatment.

Experimental study on the wave pressure of liquefied silty soil

A number of studies focus on the pore-water pressure in seabed under thewaves and seabed instability induced by liquefaction, but rarely on the wave pressureof liquefied soil. In this paper, flume tests were performed at varying wave heightsunder both conditions of liquefied and stable seabed. The total pressures equal to soilpressures and pore water pressures were measured and analyzed at each depth. Theresults showed that the liquefied seabed had little difference from the stable seabed onthe peak pressures. However, the pressure amplitude of the liquefied soil increased byseveral to 10 times and decreased faster with increasing soil depths, compared with thestable soil. According to the experiments and further analysis, an empirical equationbetween pressure amplitude of the liquefied soil and wave parameters was put forwardunder the flume test. The results provide a valuable reference for engineeringapplications.

Kinetics of Non-catalyzed Decomposition of D-xylose in High Temperature Liquid Water

The kinetics of non-catalyzed decompositions of xylose and its decomposition product furfural in high temperature liquid water （HTLW） was studied for temperature from 180 to 220℃ and under pressure of 10MPa. The main products of xylose decomposition were furfural and formic acid, and furfural further degraded to formic acid under HTLW condition. With the assumption of first order kinetics e.quation, the evaluated activation energy of xylose and furfural decomposition was 123.27kJ·mol^-1 and 58.84kJ·mol^-1, respectively.

Influence of soil liquefaction on the vertical mechanical behavior of submarine pipeline under the wave loading

In this paper, the influence of soil liquefaction on the vertical pressure of submarine pipeline was investigated under the wave loading through the wave flume test. The experiment was set with the same waves on the liquefied seabed and unliquefled seabed respectively, and the current pipeline vertical pressure was measured with the pressure transducers installed on the two opposite directions （i.e., straight up and straight down） at the same cross-section of the pipeline. The results showed that when the seabed was unliquefied, the two pressure curves varied periodically and overlapped completely, reaching the maximum and minimum at the same time respectively, and the resultant pressure fluctuated within a limited range. However, when the seabed was liquefied, the two pressure curves varied periodically, but they did not overlap completely. They did not reach the maximum （minimum） value at the same time either, and the resultant pressure fluctuated within a wider range. The experiment showed that the submarine stood higher resultant pressure in the vertical direction when the seabed was liquefied, which may cause the frequent sinking and fioatation of the pipeline, leading to its fatigue damage.

Accurate level set method for simulations of liquid atomization

Computational fluid dynamics is an efficient numerical approach for spray atomization study, but it is challenging to accurately capture the gas-liquid interface. In this work, an accurate conservative level set method is intro- duced to accurately track the gas-liquid interfaces in liquid atomization. To validate the capability of this method, binary drop collision and drop impacting on liquid film are investigated. The results are in good agreement with experiment observations. In addition, primary atomization （swirling sheet atomization） is studied using this method. To the swirling sheet atomization, it is found that Rayleigh-Taylor instability in the azimuthal direction causes the primary breakup of liquid sheet and complex vortex structures are clustered around the rim of the liq- uid sheet. The effects of central gas velocity and liquid-gas density ratio on atomization are also investigated. This work lays a solid foundation for further studvin~ the mechanism of s^rav atomization.

Water-promoted One-step Anodic Acetoxylation of Benzene to Phenyl Acetate with High Selectivity

One-step anodic acetoxylation of benzene to phenyl acetate was studied in acetic acid-water solution using a one-compartment electrochemical cell in galvanostatic mode. Compared to the anhydrous system, the addition of water improved the current efficiency for the electrosynthesis of phenyl acetate. The maximum efficiency reached 4.8% with the selectivity of 96% to phenyl acetate when the electrolysis was carried out under the optimal conditions. The investigation also indicated that the concentration of phenyl acetate increased linearly in 12 h and reached 1.07 g/L with the selectivity of 95%. Cyclic voltammetry experiments showed that the adsorption of benzene at Pt anode enhanced by the addition of water was critical to the formation of phenyl acetate. An activated benzene mechanism was proposed for the anodic acytoxylation, and the analysis of gas products demonstrated that Kolbe reaction was the main side reaction.

Preparation and Characterization of Hybrid Aqueous Dispersions Composed of Silica Sol and Poly(styrene-co-acrylate)

A stable silica sol with 3-5 nm in diameter, which can form homogeneous film without crack, was prepared and characterized. Then, the inorganic-organic hybrid aqueous dispersion composed of such a silica sol and an emulsion of styrene （St） and acrylate （Ac） copolymer was prepared and the hybrid effect between the silica sol and poly（St-co-Ac） was observed by Fourier transform infra-red （FT-IR） spectroscope. The toughness of the film prepared by this kind of hybrid aqueous dispersion was excellent, as it was enhanced appreciably by commixing with a small amount of poly（St-co-Ac） emulsion. Some amino-polysiloxane modified hybrid aqueous dispersions were also prepared and the properties of the modified dispersions and their films were investigated. The experimental results showed that the film prepared with such an amino-polysiloxane modified hybrid dispersion exhibited excellent hydrophobicity and low surface energy after heat treatment for 1.5 h, during which the formation of the graft copolymer was observed. The surface energy of this film decreases as a result of the enrichment of siloxane segments on the film surface.