Applied Mechanics and Materials Vols. 713-715

Abstract: In order to predict the absorbing properties of absorbing material effectively in theory, effective media theory was applied to reduce the effective electromagnetic parameters of several composite absorbing agents under different volume ratio. The comparison with experimental data shows that this method can well forecast the absorbing properties of absorbing material. For practical absorbing agent and penetrating agent, this method can compute the optimal proportioning and material thickness.

Abstract: A novel starch-based material, designated as DASU-EDTA, was firstly prepared by the reaction of EDTA anhydride with previously synthesized dialdehyde urea starch (DASU). This material was characterized by IR spectroscopy and used as an adsorbent to remove Cu (II) ions from aqueous solution. The IR results showed EDTA was successfully attached to the glucose units of starch, and DASU-EDTA was one of starch amides derivatives. The adsorption tests revealed that the adsorption of DASU-EDTA for Cu (II) ions was an endothermic process, which mainly relied on the strong chelation of EDTA to metal ions. The optimal conditions should be controlled at pH 5.0 and 120min. In addition, it was found that the high initial concentration of Cu (II) ions was favorable for the adsorption of DASU-EDTA for Cu (II) ions.

Abstract: With the increasing of its products, Geosynthetics materials is a very promising new type of dam materials, which is the more and more widely used. It not only has seepage control and drainage, filtration, isolation, protection and other functions, especially in the rock-fill dam seepage control applications, but also played a save the effect of project investment, shorten the construction period, which is worth popularizing in rock-fill dam engineering widespread use.

Abstract: Evaluate the influence instability by AMD corrosion based on the slope of a large-scale sulfide mine. On the basis of the corrosion experiment, carry out the researches on the solution ion change rules before vs. after evaluation; set up the mathematical expression of the AMD corrosion amount through the analysis of the corrosion mass transfer; establish the acid load deposition calculation model by AMD based on the oxidation mechanism analysis of sulfide ores; the engineering application indicates that, at the puddle, wells, sump and fracturing catchment areas, AMD acid load deposition was accumulated and the acid load is significantly higher than other area which is up to 500 mg/L; on the slope surface, as the time period affected by AMD is shorter, acid load is between 166~300mg/L; for the streams far away from mines, the acid load, less than 20mg/L, is at the minimum level. The model calculation result is consistent with the spot reality.

Abstract: Cement-Emulsifying Asphalt and waterborne Epoxy (CAE) cementing materials meet requirement for paving in steel bridge deck pavement materials, which possessing good flexibility, high temperature stability and cohesiveness to steel plate, and the microstructure model and structure formation mechanism of CAE mortar was researching in this paper. The results of the study show that, CAE mortar forms the asphalt and epoxy interpenetrating network structure which connect with cement, and the forming process contains four stage, which is dispersedness, interaction, structure formation and strength development. This structure makes CAE concrete give full play to such characteristic, which is good adhesion of cement with asphalt and epoxy resin, good temperature stability and high bonding strength of epoxy resin, good toughness of asphalt.

Abstract: Using BP neural network method, we calculate and analyze the molecular structure of aromatic hydrocarbons. Then, we get the electrotopological state indices and the molecular electronegativity distance vectors of 25 aromatic hydrocarbons based on the calculation of molecular structure characteristics and adjacency matrix. By regression, we get and optimize the structural parameters E₉, E₁₃, E₁₇ and M₁₅. The four structural parameters are used as the input variables and a 4-2-1 network structure is employed to construct a BP artificial neural network model for predicting acute toxicity pEC₅₀. The total correlation coefficient R is 0.994 and the average error between the predicted value and experimental value of pEC₅₀ is 0.079, which indicate that the ANN model has good stability and superior predictive ability. The results show that there is a good nonlinear correlation between acute toxicity pEC₅₀ and the four structural parameters. The results of our research reveal that the toxicity of aromatic hydrocarbons is closely affected by electrotopological state indices and the molecular electronegativity distance vectors. Therefore, it will be helpful in assessing the hazard of aromatic hydrocarbons to environment.

Abstract: Diisopropylamine methyl urea (DMU) was synthesized by raw materials of diisopropylamine, paraformaldehyde and urea in acid media, the effect of synthesis conditions including the dosage of hydrochloric acid, the mole ratio of the materials and the reaction temperature on the product yield were studied. A corrosion inhibitor formula that contained DMU, cyclohexylamine, ethanolamine and propiolic alcohol were designed, and static weight-loss method, Tafel polarization curve method were used to evaluate the corrosion inhibitory performance. The results showed that the best synthetic conditions for DMU were the mole ratio of diisopropylamine, paraformaldehyde and urea, 1:1.2:1; reaction temperature, 80°C; the mole ratio of hydrochloric acid and diisopropylamine 1.2:1. The product yield in this condition was 90.23%, the melting point was 230°C. The results of static weight-loss method revealed that DMU, cyclohexylamine, ethanolamine and propiolic alcohol had great synergy effect, the inhibition efficiency of gas phase static weight-loss method reached to 97.61%, and attained 85.20% in liquid phase static weight-loss method. The results of Tafel polarization curve method indicated that the corrosion inhibitor formula contained DMU had a good inhibitory effect to the cathode electrochemical corrosion process of A3 carbon steel.

Abstract: The conductive silicon rubber samples have been prepared in different filler ingredients, the platform is builded for testing the piezoresistive characteristics of conductive silicon rubber when the material is under water pressure and the test methods are designed, the body piezoresistive properties and surface piezoresistive properties under the water pressure within a certain range are studied respectively. The results show that, the sample of 6% acetylene black/2% nanoSiO₂ blends exhibit the best piezoresistive performance when the samples are under water pressure, the piezoresistive properties of the material can be improved with the increase of the thickness of the materials (2mm-4mm), and the conductive silicon rubber used for the pressure-sensitive materials of piezoresistive gauge is feasible.

Abstract: In this paper, TiC reinforced steel matrix surface composites were prepared by vacuum evaporative casting infiltration process and self-propagating high-temperature synthesis. The effect of original composition, binder types and original coating density on the hardness, wear resistance and microstructure of the coating were also studied. The results showed that the Ti and C content was 80% while added 3% PVA, by pressed at 200MPa pressure leading optimal coating quality. Meanwhile the average hardness was 48HRC and the wear rate was 40%.

Abstract: Environmental minerals, such as bentonite, kaolin, talc, attapulgite and diatomite, have abundant micropores and surface active groups. Preparation of hydrogels based on the minerals have been drawing more and more attentions worldwide because of improved salt resistance, water absorption rate, gel strength, thermal stability, water holding capacity due to addition of the minerals. Current investigations mainly focus on water absorption performance of hydrogels, insufficient concerns about porous structure, cohesiveness, surface electrical characteristics, corrosion resistance and thermal stability were paid. Novel preparation techniques with aid of ultrasonic treatment and microwave irradiation, enhancing in-situ grafting and copolymerization of biomass cellulose in mineral structures, as well as further researches on absorption mechanism of environmental mineral based hydrogels are becoming meaningful trends.