混凝电解气浮-吸附过滤处理洗染废水

采用混凝电解气浮-吸附过滤法处理洗染废水.试验结果表明:混凝电解气浮过程中,采用石墨作阴极,铁作阳极,电解电压一般控制在8~11 V,电能消耗约0.08 kW h/m3,CODC r可去除30%以上;吸附过滤过程选用新鲜粉煤灰作为吸附材料,粒度为0.3 mm,废水在吸附柱中的停留时间为2 h,CODC r可以去除50%以上.     

Avoidance of partial load operation at coal-fired power plants by storing nuclear power through power to gas

The need of fast regulation of electricity production leads to a number of inconveniences occurred to the electric generation system and the electric market, especially to the nuclear power. A new concept to control nuclear power production is posed in order to allow the regulation of the electricity sent to the grid. This concept proposes the joint operation of a nuclear power plant, a coal power plant with postcombustion capture and a methanation plant. The cost effectiveness of this technology and its capability to reduce the CO₂ emissions -consumed in the methanation process- are assessed through the design and economic and environmental analysis of a hybrid facility. Mainly due to the increase of the operating hours of the coal-fired power plant, the environmental feasibility of the initial proposal seems to be limited. However, given that benefits are expected in the medium and long-term (2020–2030) for the Power to Gas facility, a future alternative use is proposed. The target of this new alternative configuration will be the storage of CO₂ together with the storage of renewable energy.     

Multiscale characterization of carbonated wollastonite paste and application of homogenization schemes to predict its effective elastic modulus

This paper describes the multiscale characterization of the carbonated wollastonite paste using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), and statistical nanoindentation (SNI, also known as ‘grid indentation’) methods as well as micromechanical homogenization models. Wollastonite (CaSiO₃) fibers are commonly used as filler in ceramics or plastics. However, wollastonite can also be regarded as non-hydraulic binder material since upon carbonation it forms a heterogeneous matrix with mechanical properties similar to those of the conventional hydrated cement pastes. Carbonation reaction of wollastonite results in the formation of two main products: calcium carbonate (CaCO₃) and amorphous silica gel (SiO₂). The SEM/EDS microanalysis performed on this system revealed that the average calcium to silica (Ca/Si) atomic ratio of the silica gel phase was around 0.40. Three individual carbonated wollastonite paste samples, each representing a different degree of carbonation were selected for nanoindentation tests. The obtained elastic moduli for silica gel, calcium carbonate, and unreacted wollastonite grains were, respectively, 41.7 GPa, 67.3 GPa, and 134.7 GPa. The micromechanical homogenization models were then utilized to predict the effective (also referred to as ‘homogenized’) elastic moduli of the carbonated wollastonite paste. The predicted values of the effective elastic moduli of carbonated wollastonite pastes were found to be in the range of corresponding values for hydrated high to ultra-high performance cement pastes. Additionally, the values of the effective elastic moduli of the carbonated wollastonite pastes were observed to increase with the increase in the degree of carbonation.     

Required strength of geosynthetics in a reinforced slope with tensile strength cut-off subjected to seepage effects

The Mohr-Coulomb (M-C) yield criterion is found to overestimate the tensile strength of cohesive soils. By introducing the concept of tensile strength cut-off, the M-C criterion is modified to reduce or eliminate the tensile strength from the criterion. In this study, a new approach is proposed to investigate the stability of geosynthetic-reinforced slopes in cohesive soils subjected to seepage effects by means of the kinematic approach of limit analysis. The distribution of pore-water pressure is obtained using the numerical modeling software package, FLAC3D. A kinematically admissible failure mechanism is discretized to incorporate the results from the numerical simulation. The strength of geosynthetics required for maintaining the slope stability is evaluated from the work-energy balance equation. An optimization routine is used to seek out the maximum value among all possible results. Design charts providing the normalized required reinforcement under different parameters are plotted for a parametric study and convenient use in engineering. The obtained results show that less reinforcement is required in the presence of soil cohesion, and that the inclusion of the effect of tensile strength cut-off leads to a more conservative solution, which is more obvious in the presence of seepage effects.     

Strain rate dependent mechanical properties of new albany reference shale

Drilling, mining and blasting of rock-like materials, in situ fracturing, rock fragmentation size and permeability extension are strongly affected by strain rates of loading. For low strain rates, fragment sizes are large, and cracks propagate further. For high strain rates, fragment sizes are small and cracks are localized. The purpose of the present investigation is to determine the effects of strain rate on the initial (linear) value of Young's modulus and on Poisson's ratio for different grades of New Albany oil shale, a reference oil shale designated by the U.S. Department of Energy. Material anisotropy is considered. Cylindrical specimens cored in a particular orientation of the oil shale formation are tested in compression, and the rate effects are investigated. An efficient data acquisition/reduction system is developed, interfacing with an Instron closed-loop hydraulic testing machine. Strain gauge instrumentation is used to measure lateral and longitudinal strains. Strain rates of about 10⁻⁵–10⁰/sec are studied.     

Geometric view factors for thermal radiation hazard assessment

Estimating the thermal radiation field surrounding a large fire involves characterization of the flame geometry and computation of radiant intensity at a given location. The latter requires computation of geometric view factors. In this article, closed form expressions that are common in the design of impoundment systems. These include tilted cylindrical and rectangular geometries. The computed geometric view factors compare very well with limited experimental data for circular geometries. The closed form expressions allow rapid computation of view factors that are necessary in estimating the fire hazards associated with large hydrocarbon pool fires.     

Electrochemical performance of Al-substituted Li_3V_2(PO_4)_3 cathode materials synthesized by sol-gel method

The effect of Al-substitution on the electrochemical performances of Li3V2(PO4)3 cathode materials was studied.Samples with stoichiometric proportion of Li3AlxV2-x(PO4)3(x=0,0.05,0.10)were prepared by adding Al(NO3)3 in the raw materials of Li3V2(PO4)3.The XRD analysis shows that the Al-substituted Li3V2(PO4)3 has the same monoclinic structure as the un-substituted Li3V2(PO4)3.The SEM images show that Al-substituted Li3V2(PO4)3 has regular and uniform particles.The electrochemical measurements show that Al-substitution can improve the rate capability of cathode materials.The Li3Al0.05V1.95(PO4)3 sample shows the best high-rate performance.The discharge capacity at 1C rate is 119 mA·h/g with 30th capacity retention rate about 92.97%.The electrode reaction reversibility and electronic conductivity are enhanced,and the charge transfer resistance decreases through Al-substitution.The improved electrochemical performances of Al-substituted Li3V2(PO4)3 cathode materials offer some favorable properties for their commercial application.     

Boron removal by hydrotalcite-like,carbonate-free Mg–Al–NO3-LDH and a rationale on the mechanism

Removal of boron from boric acid and tetraborate solutions by hydrotalcite (HT)-like, carbonate-free, Mg–Al–NO₃-layered double hydroxide (LDH) was studied. Data from batch experiments were computed as a function of the adsorbent dose and contact time. Synthesis in CO₂-free conditions provided a material with high anion exchange capacity and more than 95% adsorption could be achieved. The physical and structural properties of the material before and after boron adsorption were investigated to describe the uptake mechanism. Interpretation of the results of d-spacing, surface area and zeta potential measurements indicated an anion exchange mechanism rather than surface adsorption. Calcination at 400 °C did not make any significant change in the removal process.     

Fabrication of high-performance Y2O3 stabilized hafnium dioxide refractories

Y₂O₃ stabilized HfO₂ ceramics with 5 mol% and 8 mol% Y₂O₃, respectively, were successfully fabricated by pressureless sintering at 1600 °C for 1 h. The phase distribution and transformation, microstructure, and relative density were investigated for Y₂O₃ stabilized HfO₂ ceramics. Cubic phase was observed in the Y₂O₃ stabilized hafnium dioxide while pure HfO₂ showed monoclinical phase only. The SEM images of fractured surface indicated two kinds of structures existed in modified HfO₂, the solid solution region and uniform polygon grains, and some holes caused by Kirkendall effect. Refractoriness test showed that high temperature volumetric stability of the material can be effectively enhanced by adding Y₂O₃ into HfO₂.     

野生火棘果中黄色素的提取

以野生火棘果为原料,用已获得的提取红色素的方法将火棘果中的红色素提尽,然后用乙醇作提取剂从火棘果渣中提取天然黄色素。探讨了料液比、提取时间、提取次数和提取温度等因素对火棘果黄色素提取效果的影响,通过L9(34)正交实验确定了最佳工艺参数。结果显示,火棘果黄色素的最佳提取条件为:料液比1∶9,提取时间75min,提取次数5次,提取温度60℃,此时,黄色素的提取率为92.5%,产率为2.1%,色价为22.2。火棘果黄色素为脂溶性色素,其乙醇溶液在可见光区内的最大吸收波长为450nm。