Advanced Materials Research Vols. 156-157

Abstract: When designing the capacitance of a Multi-Layer Ceramic Capacitor (MLCC), engineers used to focus on the way to find appropriate combination of the design parameters. These design parameters usually include materials, layer numbers and thicknesses of the electrodes and the dielectrics. However, not considering the mechanical strength in the design stage may lead the manufactured MLCC prototypes to fail in material test, and a redesign is very often needed. Such a design-and-redesign process is inefficient and needs to be improved. The present paper proposes a simple and efficient design approach to replace the traditional one. It first identifies an empirical equation correlating the capacitance of a MLCC to the design parameters based on specifications. The strength of the MLCC can be evaluated in advance with the help of mechanics of material. A design platform which considers simultaneously the capacitance and the material strength under various design parameters can be established. Demonstration of a MLCC design by the developed platform indicates the proposed approach does help engineers improving and speeding their designs.

Abstract: This study investigated the impact of five organic loading rates (OLRs) ranging from 16 kg COD/m3-d to 32 kg COD/m3-d on the performance of a continuous stirred tank reactor (CSTR) for biological hydrogen production, with molasses as substrate. Hydraulic Retention Time (HRT) was kept at 6 hours and the temperature 35°C. Oxidation-reduction potential (ORP) varied from -328 mV to -419 mV. The ethanol-type fermentation has been conducted during the process. A positive statistical correlation was observed between OLR and biogas yield; however, it became negative for the OLR of 32 kg COD/m3-d (Fig1). The system maintained the highest average biogas and hydrogen yield of 14.66 L/d and 5.17 L/d at OLR of 28 kg COD/m3-d. Compared with the first stage (16 kg COD/m3-d), ethanol and butyric concentration of the last stage (32 kg COD/m3-d) increased about 2.01 and 3.79 times, respectively; Acetic acid concentration surged around 200 mg/L; Prop ionic acid concentration dropped slightly; Valeric acid concentration, which took a small portion in the volatile fatty acid (VFA), kept low. When OLR was kept at 28 kg COD/m3-d, the average ethanol to acetic acid ratio is 3.90.Thus proved that the optimal OLR for hydrogen production under experimental condition is 28 kg COD/m3-d.

Abstract: Discussed in detail using BP neural network to establish the quantitative relationship model between the process parameters and components density on the laser direct rapid forming (LDRF) metal parts, in which input of single-pass sintering model is: laser power (P), scanning speed (V ) and powder feeding rate (G), performance indicators to measure the width of the sintered layer (W) and height (H); input of multi-pass multi-sintering model is: P、V、G、scan spacing (D) and layer thick ( ), the performance measure for the density of sintered parts，And neural network simulation results and experimental results are analyzed and compared. The results show that using BP neural network model can quantitative analyze the effect on sintering process parameters and the sintering performance, the model for the optimization of LDRF process parameters has built the foundation.

Abstract: Electricity can be generated during the wastewater treatment by microbial fuel cell (MFC). Effect of the anode pretreatment method, anode modification and electronic media in anolyte on electricity generation of a single chamber microbial fuel cell (SCMFC) with an air cathode was investigated by performance measurement of the MFC during one cycle of generating electricity. Results show that the discharge time of MFCs with stainless steel anode pretreated by NH4Cl and HCl is longer than that with anode pretreated by the distilled water and NaOH; the performance of MFC with anode pretreated by NH4Cl is the best; comparison with stainless steel anode and adhere activated carbon, the current of MFC with the stainless steel anode adhere the carbon fiber is the maximum and its Coulombic efficiency is the highest; The electricity generation characteristics of the MFC with the anode adhered carbon fiber and pretreated by NH4Cl and the anolyte added the electronic media is the best. The action of the electronic medium and the NH4Cl on the MFC is synergism. It's of great significance that the research results improve the performance of MFC by anode pretreatment.

Abstract: Long-life electronic products need to be put in stress environment for long durations in traditional ESS(environmental stress screening) tests in order that items having infant mortality or defects are weeded out from products. However, long stress durations cause aging effects on good items. For some products, failures are defined in terms of performance characteristics degrading some critical values. For the purpose of reducing durations and aging effects, this paper analyzes the difference of performance characteristics between normally degraded products and abnormally degraded products, and assumes the distribution of products’ degradation characteristic variable is contaminated distribution model, then presents a degradation screening test design. This design firstly ascertains the model coefficient using identifiable condition of contaminated distribution combined with the analysis of degradation test, then ascertains screen duration and screen critical value. Lastly, this paper gives an example to illustrate the availability of the design.

Abstract: The paper introduces the modeling process of space assembly relations of bits and bit-holders of roadheader cutting heads. Through the realization of a single bits and bit-holders positioning and assembly, by using the second development tool - Family Table, achieved all bits and bit-holders assembly of roader header cutting head; programmed with Matrix Formulations of Matlab and began load simulation. Written procedures with short, readable, easy to modify, and practicability for application.

Abstract: Mn2+-doped zinc borosilicate glasses (ZSBM) with excellent long-lasting phosphore- scence (RTSLLP) and photostimulated long-lasting phosphorescence (PSLLP) were successfully synthesissed by high tempreture solid-state reaction. Through increasing the ratio of SiO2/ B2O3 with fixing the content of ZnO in 60mol%, RTSLLP and PSLLP were improved obviously. By TL study, it was seen that the traps concentration had a big change with the increasing in silica content, which bringed a positive impact on the RTSLLP and PSLLP, especially PSLLP performance, and through infrared absorption spectrum analysis, it was confirmed that the distribution of trap-level was closely related to the silicon oxygen groups and boron oxygen groups.

Abstract: Utilizing finite element software, an universal program has been worked out by the APDL, and it can output the heat dissipating capacity of appointed surfaces in analysis software. The program is so powerful that it can calculate the heat dissipating capacity of heat conductor in which the heat transfer two-dimensionally or three-dimensionally even if the heat conductor is anisotropic, which is difficult to calculate with the mathematic analysis method. The method mentioned in the paper can diminish the inaccuracy caused by the predigestion with the mathematic analysis method. The calculation principle of the program was introduced in detail. Comparing the result of the program with that got by mathematic method, it was indicated that the calculation error of program is very small.

Abstract: The heavy load deflection angle milling head is an important functional component of 5-axis CNC machine tool, which is used for large and complex free-form surface processing. The characteristics of this kind of milling head are implementing multiple degrees of freedom motion with revolution and deflection angle simultaneously. Obtaining milling head dynamic and static characteristics is a pre-requisite problem to resolve for the development and research of heavy load deflection angle milling head independently. Dynamic characteristics are obtained through combination with CAE (Computer-aided Engineering) technique and experiment validation. For CAE analysis, the main parts of milling head are glued together considering milling head operating at a specific position. Experimental validation is carried through with initial fixing constraint style, which validates the correctness of CAE technique. Experimental and CAE analysis results are compared and analyzed. Therefore, exact dynamic characteristics of milling head and unsubstantial segments and its influence factors are gotten. Static characteristic is obtained considering milling head operating in different posture by CAE technique. The analytical method of three points at half of cutter are loaded is introduced. Calculated results indicate that the deformation of tool tip is the largest when milling head operating in 45° posture, which corresponds with the deformation situation of the milling head operating in workshop. The analytical results of dynamic and static characteristics of milling head provide theoretical and experimental support for structure optimization and improving of heavy load deflection angle milling head.

Abstract: Orthogonal test method was applied to optimize the ultrasonic extraction of proanthocyanidin from peanut skin. On the basis of single factor test, the influencing factors of extraction power, temperature, time, solid-liquid ratio, ethanol concentrationultrasonic frequencies were determined by orthogonal test method with five factors and four levels in the ultrasonic frequency of 28 KHz. The results of the orthogonal test showed , the effects of five factors on ultrasonic extraction of proanthocyanidin from peanut skin were listed in the order of importance as: solid-liquid radio > ultrasonic power > time > temperature > ethanol, the optimum extraction conditions were as follows: ultrasonic output power 120W , extraction temperature 35°C, extraction time 5 min, solid-liquid ratio 1:24, ethanol concentration 55%.Under the optimum extraction, the extraction rate of proanthocyanidin was 12.1%.