Advanced Materials Research Vol. 742

Abstract: The failure behavior of Poly (ether urethanes) in ozone atmosphere was investigated by FTIR, UV-Vis spectra and SEM analysis. It is found that some oxygen-containing groups such as the hydroxyl group and the carbonyl group increase first and then slightly decrease with the ozone oxidation time and the carbohydryl and ether bonds decrease slowly. After oxidation by ozone, the polyurethane molecule chains break on C-O in ether and urethane groups instead of chain crosslinking. In addition, ozone oxidization increases the color difference and lowers the UV light transparence of polyurethane.

Abstract: The aim of this study was to study the effect of nanoSiO₂ on durability of high performance concrete. Four different nanoSiO₂ contents (1%, 2%, 3% and 4%) were used. The results indicate that the content of nanoSiO₂ has great effect on the durability of high performance concrete. With the increase of nanoSiO₂ content, both of the length of water permeability and the carbonation depth of concrete are decreasing gradually, and the water impermeability and the carbonation resistance of concrete are increasing gradually. However, with the increase of nanoSiO₂ content, there is a tendency of increase on the dry shrinkage strain of 90 days of high performance concrete, and the anti-dry-shrinkage cracking property of concrete is decreasing.

Abstract: This paper describe a laboratory investigation into the effects of adding silica sand and/or cement on the behaviour of artificial carbonate sand under shear and compression. Drained shear and compressibility tests have been performed on artificial carbonate sand samples and artificial carbonate sand samples mixed with different proportion by weight of silica sand and/or cement in order to determine the shear stress-strain and compressibility characteristics of the mixed material.The results demonstrate that contraction during shear and compressibility during isotropic compression decrease as the fraction of silica sand and/or cement increases within the artificial carbonate sand.A positive volumetric change (dilation) during shear is more obvious with cemented samples. It also demonstrate how the addition of a combination of silica sand and cement produces the most effective improvement in terms of strength, stiffness, compressibility and crushing.

Abstract: Brazilian Expanded Clay. The production process in a rotary kiln (or nodule) used in Brazil, characterized by the fact that certain materials expand when subjected to high temperatures (between 1000 °C and 1350 °C), such as some clays. In this temperature range, some of the material melts generating a viscous mass, while the other part chemically decomposes releasing gases which are incorporated by this mass, expanding by up to seven times its initial volume, the pore structure being maintained after its cooling. This manufacturing process promotes the formation of a glazed layer on the outside with low particle porosity, which significantly reduces the water absorption, has varying particle size and regular rounded shape, and its specific gravity comprised within the range from 0.64 to 1.51 kg/dm^{3 [4,} .

Abstract: Due to their exceptional mechanical properties,xerogels attract increasing attention forstructural applications. In this study, the mechanical behavior of two types of polymeric xerogelsis investigated. The excellent energy-absorbing capability of those xerogelsis demonstrated by their stress-strain relations with respect to their microstructure determined withscanning electron microscopy (SEM). A pilot study on the effects of xerogellayers in an FRP system for concrete confinementis conducted.Test results clearly indicatedthat the proposed multi-layer systemcan significantly increase the ductility of confined concrete.

Abstract: Based on the strength tests, including compressive strength, split tensile strength, shear strength , of steel fiber reinforced concrete (SFRC) with different concrete strength grades (C20~C50) at low fiber volume fraction (0~0.7%), the influences of concrete strength grades and steel fiber volume on concrete strengths were studied, and the effect significance levels of the two factors was analyzed through the binary variance analysis. The results show that when the concrete strength grades are amongst C20 ~ C50 and steel fiber volume rates lie in the range 0~0.7%,the strengths of SFRC rises as concrete strength grade and steel fiber volume ratio increase ; the influence of concrete grade is more significant than that of steel fiber volume ratio on compressive strength and split tensile strength of SFRC; the influence of steel fiber volume fraction is less significant than that of concrete strength grades on shear strength of SFRC.

Abstract: Co-firing has been adopted as a major approach for the efficient use of biomass as an energy source in large scale for two decades. Such a practice contributes to the decarbonisation in power generation sector and therefore to the mitigation of CO₂ emission. However, due to the differences in terms of thermal behaviors between biomass and coal, the co-firing of some biomasses with coal still presents many engineering problems, such as excessive fouling and slagging, which subsequently result in deteriorated boiler efficiency. The understanding of the transformation of minerals upon heating and how minerals originated in biomass affect ash fusion characteristics is of some significance for both design and operation purposes. In this study, low temperature ash (LTA) samples of biomass and coal were prepared and analyzed by using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled energy diffraction spectrum (EDS), the results of which were compared with their corresponding high temperature ash (HTA) samples. The transformation of minerals upon heating was therefore studied. The ash fusion characteristic temperatures of ash samples derived from different biomass and coal blends were investigated. The ash fusion characteristic temperatures show some additive behaviors.

Abstract: Enhanced Oil Recovery has been used in most oil field of China, but the oil field wastewater was more difficult to treat than that from water flooding. In this paper, FX flocculants (FX-F) prepared in our laboratory was chosen as the optimal flocculants compared with aluminium polychlorid (PAC), polyaluminium ferric chloride (PAFC). The optimal dosage of FX flocculants was 4 mg/L based on the field test, at which the SS content of treated oil field wastewater reduced sharply within 10 hours. The 15 mg/L of the FX-F would be the most convenient to form the sludge layer. Taking FX-F as flocculants, the oil field wastewater was treated in the micro-flocculation suspended sludge filtration process, and the results showed that the SS and Oil of wastewater could be significantly be reduced. In the end, the average oil content was lower than 1 mg/L and the removal rate can reach 99%, and the average content and the removal efficiency of SS was 1.26 mg/L and 95% respectively, which can really meet the standards for oil field rejection water.

Abstract: The sediments in all kinds of containers in oily field ground processing system were called tank bottom oily sludge. In this paper, the characteristics of sludge were studied. The colloid and asphaltene can increase strength of the oily-water emulsion film which can lead to seriously oily emulsion. In view of this, the process of conditioning-ultrasonic demulsification-centrifugal separation treating tank bottom oily sludge was designed by studying the sludges physical and chemical characteristics. The process parameters were selected. The conditioning were that the dose of detergent was 600 ~ 800 mg/L; The ultrasound processing was that the temperature was 60°C, the ultrasound power was 12Kw and the running time was 25min; The centrifugal separation was that the temperature was 60°C, the dosing flocculant was 600mg/L and centrifuge rotating was 2200r/min. The oily containing in the sludge of centrifugal exports was less than 2% by using this process at the optimal parameters.

Abstract: In order to study the surface subsidence and separation range features during the mining process in in thick seam mining of Daping mine , it takes the typical coal of mining in S₂S₉ face of Daping Mine, using the resemble simulation to study on it. The study showed that the subsidence amounted to less than the maximum under the geological and mining conditions, In the single-face mining conditions, when the face length is generally not more than (1/3-1/4) H.The mining thickness cannot deflection in the form completely transmitted to the surface, but abound in overburden bed rock mass formed within the fracture and caving into the residual space. This research can be a reference for safety and high efficient coal mining of other working face in Daping Coal Mine.