Advanced Materials Research Vols. 450-451

Abstract: Mixed light aggregates can effectively reduce the coefficient of thermal conductivity of composite materials. Through orthogonal experiments of thermal insulation mortar containing mixed ceramic sand and vitrified micro bead aggregates, we analyzed the law of influence of relevant factors on the dry bulk density, coefficient of thermal conductivity and compressive strength of mortar containing mixed ceramic sand and vitrified micro bead aggregates and provided basic data for further improvement of such thermal insulation mortar so as to promote the development and application of high performance thermal insulation materials.

Abstract: A wall of aerated concrete only can hardly meet the requirements for energy-saving architectural design. If both sides of the wall are provided with thermal insulation mortar to form a composite wall, the heat transfer performance of the wall will be significantly improved. In this Paper, we established an optimization model for the thermal economy of a thermal insulation composite wall according to heat transfer theory and in consideration of the depreciation and maintenance costs of the wall during use, and took the average heat transfer coefficient and index of thermal inertia of the wall as restricted conditions to calculate and analyze the economical thickness of the thermal insulation layer. We expect the optimization model be valuable reference in promoting the application of aerated concrete-based composite thermal insulation walls.

Abstract: Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. To optimize the reduction technology of SSI and its removal ability for nitrate from wastewater, the influence of reduction time of SSI on nitrate removal percentage was investigated. Because the specific surface area was impact smartly by the reduction time of SSI, it was suggested that nitrate removal ability of SSI should declined with the increasing of reduction time once the reduction time longer than the optimized reduction time. When the reduction time was t1, nitrate removal percentage reached to the maximum. When the nitrate original concentration was 5mg-N/L, the reaction order was closed to 0.7 and the apparent reaction rate constant was 0.323 to 0.359 h-1. When nitrate original concentration increased to 50 mg-N/L, nitrate removal reaction appeared to be the pseudo-first-order reaction, and the apparent reaction rate constant was 0.314 to 0.248 h-1.

Abstract: Public service evaluation based on fuzzy analytic hierarchy process is presented in the paper. Firstly, evaluation indexes of public service are analyzed,and the three-layer evaluation indexes structure is composed of these evaluation indexes of public service. A certain public service organization is employed to study the evaluation performance of the proposed fuzzy analytic hierarchy process method,and the evaluation values of second-level evaluation indexes are given.By analyzing based on fuzzy analytic hierarchy process,the evaluation values of the public service are given.The experimental results indicate that the evaluation level of the public service organization is consistent with the actual situation.

Abstract: The composition and structure of the interfacial transition zone (ITZ) in concrete were investigated to analyze the mechanism of silica fume in suppressing alkali-silica reaction (ASR). Alkali active concrete specimens with varying addition of silica fume were prepared for the experiment. Changes of compositions and pore structures at ITZ and the elements distribution across ITZ were analyzed by SEM and SEM-BSE. The expansion of the corresponding mortar bar was also measured. The results show that the accumulation of element of alkali metal occurred at ITZ in alkali active concrete without silica fume, while the characteristics of the ITZ are basically similar to those in conventional concrete. By addition of silica fume, the ITZ in alkali active concrete are changed and have the following features: disappearance of the accumulation, occurrence of the C-S-H gel with a lower CaO/SiO2 ratio, decrease in crystal phases of Ca(OH)2 and ettringite, and in porosity. These changes account for the mechanism of Silica fume in suppressing ASR.

Abstract: The sintered shale brick and light-weight sintered shale brick are both of brittle wall materials. The mechanical and other properties will be affected greatly by tensile force producing the lime burst. Through analysis of physical and chemical properties of raw materials, the reason of lime burst, and the comparative experiments of lime burst, studied on similarities and differences between the two wall materials, providing important technical parameters for the follow-up research, production and construction in the feature.

Abstract: Epoxy resin (EP) be widely used owning to its superior performance and usability, however the flammability of EP bring trouble for its application. So, flame retardant of EP is very important research subject. This article reviewed the flame retardant methods for EP, and introduces research results from the types of phosphorus-containing flame retardant, organic montmorillonite (OMMT) flame retardant, hydrogen peroxide flame retardant and double hydroxyl hydroxides (LDH) flame retardant respectively.

Abstract: This article researched fly ash-epoxy resin composite properties and microstructure changing with the increase of epoxy resin content. The result show that, when the epoxy resin content increased to 30%, the tensile strength, rupture elongation and impact strength of composite increased to 329%, 168% and 257% respectively compare with the composite of epoxy resin content is 15%, and various properties change little with the epoxy resin content continuous increasing. And the composite formed 2μm or so and uniform distributed micro-pores when the epoxy resin content is 30% and the consistency of micro-pores increasing and some small micro-pores gathered into larger with the epoxy resin content increasing. Considering various properties, the fly ash-epoxy resin composite has the highest cost-effective when the epoxy resin content is 30 ~ 40%.

Abstract: The aim of the present paper is to establish some new sum-difference inequalities which provide explicit bounds on unknown functions. The inequalities given here can be used as tools in the qualitative theory of certain partial difference equations

Abstract: The compound photocatalytic materials of TiO2/SnO2 films with bilayer structure supported on polyacrylonitrile based carbon fiber (PAN-CF) substrates were prepared via the dip-coating technology, and Titanium dioxide (TiO2) and tin dioxide (SnO2) precursory sol were prepared by sol-gel method. Field emission scanning electron microscopy (FE-SEM), X-ray energy spectrum (EDS) and X-ray diffraction (XRD) were used to characterize the structure of materials, and methyl orange (MO) with concentration of 80mg/L as the target degradants was used to investigate the photocatalytic property of the composites under UV irradiation. The results revealed that the photocatalytic activity of composite is effectively enhanced result from the application of TiO2/SnO2 bilayer structure films, which can be considered as that the recombination of photo-induced electrons is restrained by SnO2 film effectively, and the 3#-TiO2/SnO2/CF exhibited optimum catalytic performance. In addition, the superiority of carbon fiber as carrier was played fully due to the generation of porous films, which is favorable to capture the intermediate products.