Advanced Materials Research Vols. 403-408

Abstract: This study was done to access the influence of salinity on the treatment of tannery wastewater, activity of sludge and morphological characteristics of the salt-tolerant bacteria cultivated using tannery wastewater as culture mediums and intermittent aeration as method. The results indicated that， aerobic sludge which contained salt-tolerant bacteria was cultivated under the conditions of temperature of 35°C and pH = 8, the COD removal in simulated and actual tannery wastewater was more than 87% and 85% by the cultivated aerobic sludge, respectively. In addition, the morphological characteristics were related to the composition and concentration of the salt. The average generation time of bacteria was 24.6min ~ 28.6min when the concentration of MLSS was 2.0 ~ 3.0g/L and the concentration of pure NaCl was 1 ~ 5g/L. As the volume ratio of NaCl and Na2SO4 was 4:1 ~ 1:4 with the total concentration of 5g/L, the average generation time of bacteria was 30.8min ~ 39.7min. The relation equation between salt concentration and the average generation time of bacteria under the pure salt, composite salt and actual tannery wastewater conditions was also deduced through four assumptions. The results had significant application on tannery wastewater treatment with great reduction of pollution.

Abstract: TiB2-TiC intermediate metal powder was fabricated via mechanical alloying (MA) processing, and the phase formation and powder morphology characteristics were studied by using X-ray diffraction（XRD）, scanning electron microscopy (SEM), differential thermal analysis (DTA). Starting materials were milled at ambient temperature in argon protective atmosphere. Prepared intermetallic phase of TiB2-TiC included, Ti3B4、Ti2B5、TiC0.06. Used milled powders prepare TiB2-TiC composition via two-way vacuum hot pressing sintering furnace not only decrease the time of preparation, but also reduce temperature of reaction, because of the preactivation reaction during MA promote the reactions. Therefore, this process will promote TiB2-TiC composite ceramics in engineering applications.

Abstract: Tin oxide (SnO ₂) ,MgSnO₃ and Mg₂SnO₄ nanocrystals have been synthesized by one-step solid-state reactions. in the first step, The powder of SnCl ₄.5H₂O was mixed with MgCl₂ and Mg(OH)₂with weight ratio of Sn to Mg (1:1), (2:1) And (1:2) in an air atmosphere at room, and annealing temperature in this work were 200°C, 400°C ,600°C , 800°C and 1000°C . XRD patterns show the SnO₂ , MgSnO₃ and Mg2SnO₄ particle size of synthesized powders by MgCl₂ were 3 nm, 4nm and 27 nm respectively. In fact the excess amount of Mg role of crystallite growth inhibitor in SnO ₂. this method is a simple ,inexpensive ,efficient and economic preparation for SnO ₂, MgSnO₃ and Mg₂SnO₄ nanoparticles with adjustable grain sizes in the range of 3-44nm in high yield. This article shows the role of mass MgCl₂ in producing of SnO₂ nanoparticles.

Abstract: This paper reports on the deposition of semiconducting amorphous carbon (p-aC) films fabricated onto the glass substrate and n-type silicon by Thermal Chemical Vapor Deposition (CVD) using natural source of camphoric carbon as the precursor material. Those samples were deposited at 5 different temperatures from 3500C to 5500C. From the characterization of the electrical properties using current-voltage (I-V) measurement, I-V graph was modeled for both conditions, where for a-C thin films linear graph (ohmic) were performed, whereas for the device, a rectifying graph were obtained. The analyze revealed that conductivity shows an increment as deposition temperature increased, both in dark and under illumination condition. On the other hand, the solar cell device of the p-aC/n-Si achieved an efficiency of 0.1111% for the a-C deposited at 3500C. Other than that, optical properties were also characterized by using UV-VIS-NIR system. The same trend of optical and electrical can be seen when the measurement from the Tauc’s plot expose a decreasing value of optical band gap as temperature increase.

Abstract: This paper concerned with modeling of the strain rate dependent material behavior of 3D-textile composites with simultaneous consideration of production and operational (e.g. pores or fatigue damage) defects. Therefore an additive model in the sense of continuum damage mechanics was introduced. For the model validation extensive experimental tests on glass non-crimp fabrics reinforced epoxy (GF-NCF/EP) composites are performed. The focus is put on the influence of production and fatigue related pre-damage under subsequent highly-dynamic tensile loading. The theoretical studies shows a good coincidence with the experimentally results

Abstract: Asphalt mixture is often modified by adding modifier in order to improve the pavement performance such as high temperature stability, low temperature crack resistance and water stability. The author applies a new type of polyethylene modifying additive for asphalt mixture. The adding method of modifier is different from traditional method. Three modifiers were used in this study. It has been found that each modifier can improve the asphalt mixture performances. The author analyses the reason why modifying additive can improve asphalt mixture performances and give an advice to choose the type of modifying additive.

Abstract: A Magnetohydrodynamic pump uses the Lorentz effect. It is based on the injection of an electric field into two electrodes located at facing side walls of a channel. The purpose of this study is to numerically investigate the effect of Nanofluid properties on the flow field as well as the temperature distribution in a MHD pump. To solve the non-linear governing differential equations, a finite difference based code is developed and utilized. The temperature and velocity are calculated by solving the energy and Navier-Stokes equations. Result shows that temperature stays almost constant with magnetic field. Furthermore velocity and temperature behaviours are similar for each period. However heat transfer inside the MHD pump varies with nanofluid (NaCl solution and Al2O3 nanoparticles) in comparison with the NaCl solution.

Abstract: The flow stress at the temperature of 250~450°Cand different strain rate of casting AZ91D magnesium alloy was studied through experiment, which adopting the Gleeble 3500 system of DSI company. The mathematical model of flow stress containing the softening factor which is suitable for casting AZ91D magnesium alloy was proposed. The temperature and strain rate conditions during full dynamic recrystallization were found by observing the microstructure.

Abstract: Bridgewire of a thin resistive wire widely used in electric explosive devices (EED) as a transducer of electronic energy to thermal energy provide the ignition of energetic compounds. In this paper the temperature variation laws of bridgewire as core component and most sensitive part for EED under the constant current were investigated though infrared measuring temperature system. The result indicates that the thermodynamic equilibrium from the bridgewire was realized in two senconds and the maximum temperature for bridgewire caused by the current rises as quadratic parabola with increasing of current acting on bridgewire. Meanwhile the safety current for bridgewire with large diameter is higher than that for bridgewire with small diameter. The maximum temperature variation curve for bridgewire of different diameters with current received from the infrared thermal imaging can provide the quantitative evidence supporting the predication of safety current for bridgewire and guidelines for engnieers to realize the activation of EED as expected safely.

Abstract: This study used Six Sigma DMAIC five-phase improvement procedures for an empirical research on a multinational optical interconnect manufacturer. The Taguchi method was used for the design of experiment, and the data obtained from the orthogonal table were used to determine the key factors and levels, in order to propose the optimal combination of processing parameters and levels for fiber patch cord 3D polishing. The combination of rough polishing time of 30s, polishing pressure of 0.02pa, polishing pad hardness of 65 degrees, and the fine polishing time of 80s could produce the fittest parameters for a satisfactory level, reduce the defect rate and waste of production cost, and reach the Six Sigma standard. The results proved that the improved process capability model, as constructed by this study, can effectively improve the apex offset quality of fiber patch cords. The findings can serve as references for engineers to improve the quality and production process capability.