A comparison of the behavior of different customer clusters towards Internet bookstores

This research was initiated in an attempt to understand customer intentions towards purchasing from an Internet bookstore. Ajzen's theory of planned behavior was used to predict the intentions and behavior of different customer groupings based on their lifestyle and personality. Factor and cluster analyses were used to segment the sample into three clusters. Data were then collected in seven colleges in Taiwan. After analyzing the results, various relationships between attitudes, subjective norms, perceived behavioral control, behavioral intention and real behavior were determined for the different groups.     

Characterization of crack-tip field and constraint for bending specimens under large-scale yielding

Elastic-plastic crack-tip fields and constraint levels in bending specimens under large-scale yielding (LSY) are examined. The J–A ₂ three-term solution is modified by introducing an additional term caused by the global bending. Three different methods, i.e. two-point matching, constant A ₂ and elastic stress estimation method, are proposed to determine the fourth term. It is shown that the elastic stress estimation method is the simplest, yet effective, in that the fourth term can be derived from the strength theory of materials and the concept of plastic hinge, and effectively quantifies the contribution of the global bending moment on the crack-tip field. Consequently, the modified J–A ₂ solution, with the inclusion of the correction for global bending, does not introduce any new parameter. The two parameters remain as the loading (J and M) and the constraint level (A ₂). To validate the present solution, detailed finite element analyses (FEA) were conducted for a Three Point Bend (TPB) specimen with a/W=0.59 in A285 steel, and Single Edge Notched Bend (SENB) specimen subjected to pure bending with a/W=0.5 in A533B steel at different deformation levels ranging from small-scale yielding (SSY) to LSY. Results show that the modified J–A ₂ solution matches fairly well with the FEA results for both TPB and SENB specimens at all deformation levels considered. In addition, the fourth stress term is (a) proportional to the global bending moment and inversely proportional to the ligament length; (b) negligibly small under SSY; and (c) significantly large under LSY or fully plastic deformation. Accordingly, the present model effectively characterizes the crack-tip constraint for bending dominated specimens with or without the large influence from the global bending stress on the crack-tip field.     

Exploring the role of espoused values on e-service adoption: A comparative analysis of the US and Nigerian users

Technology adoption in developing and developed countries needs to be studied and contrasted in order to identify similar and unique factors which impact adoptions. Information technology acceptance and the influence of espoused values (EV) have been investigated in developed countries but such studies are rare for developing countries. The present study surveyed 201 Nigerians and 188 Americans using constructs based on accepted theories, with the aim of comparing the influence of national culture on the acceptance of e-services in each country. The combined data indicate that user satisfaction with e-services is affected by perceived usefulness and information/system quality (with R² = 0.64). User satisfaction, in turn, affects users’ behavioral intention to continue to use e-services (R² = 0.50). EVs moderate the effect of perceived usefulness and information/system quality on satisfaction. In general, the moderating effects of EVs are more pronounced for Nigerian respondents than for US respondents, due to national cultural differences.     

Influences of feedstock and plasma spraying parameters on the fabrication of tubular solid oxide fuel cell anodes

This study developed a tubular solid oxide fuel cell (SOFC) anode support layer via atmospheric plasma spraying, which is considered one of the most promising methods for producing SOFCs because of its faster deposition rate and lower cost compared with other film formation processes. Plasma spraying can replace the traditional use of extrusion technology to manufacture the anode base tube, eliminating the need for high-temperature sintering steps. In this study, commercially available powders were used to make the anode of a tubular SOFC from NiO/yttria-stabilized zirconia (YSZ) powder, and Na₂CO₃ and polymethyl methacrylate were tested as pore-forming agents. The anode composite powder was sprayed on the graphite base pipe, and the final product was changed by altering the spraying parameters and anode powder ratio. The direct current (DC) resistance measurements showed that the conductivity of the Ni/YSZ tubular anode formed with higher power plasma spraying could reach 428.55?S/cm at 800?°C. The experimental results showed that the power and parameters of atmospheric plasma spraying could affect the porosity and electron conductivity of tubular SOFC anodes.     

Film percolation for composite electrodes of solid oxide fuel cells

A film percolation model is proposed for composite electrodes of solid oxide fuel cells (SOFCs). The model is developed to predict the percolation properties of 2D-infinite structures which represent the structural characteristics of composite electrodes of electrochemical devices such as SOFCs. The model can be used to estimate electrode properties, such as percolation probability, active three-phase boundary length and interfacial polarization resistance. Compared with the classic percolation theory, which is particularly applicable to 3D-infinite bulks, the model can explicitly capture the effects of thinly layered nature of composite electrodes, and describes a cross-over between 2D-infinite films and 3D-infinite bulks. It also permits the prediction within whole electrode composition range, and can be easily applied in SOFC modeling.     

基于SEM的诱发矿工故意违章行为因素的实证分析

为减少矿工故意违章行为,降低安全事故发生率,以计划行为理论(TPB)为基础,利用突显信念(行为信念、规范信念、控制信念),结合一线矿工实际作业情况,对诱发矿工故意违章行为的因素进行分析,并构建诱发因素与故意违章行为之间关系的结构方程模型(SEM)。收集王庄煤矿132名一线矿工有效调查问卷,对诱发矿工故意违章行为的因素进行实证研究。结果表明,故意违章行为意向对故意违章行为有显著的正向影响;安全意识、领导监管力、班组安全气氛、工作环境通过故意违章意向负向影响故意违章行为;工作强度通过故意违章意向正向影响故意违章行为。对诱发矿工故意违章行为因素进行有效管理是降低故意违章行为的重要途径。     

三苯基铋对高燃速丁羟推进剂的催化固化作用研究

研究了三苯基铋（ＴＰＢ）对高燃速丁羟推进剂的催化固化作用。实验结果表明,ＴＰＢ可降低该推进剂的固化温度,缩短固化时间,而且对其加工性能和力学性能都无副面影响,同时还发现ＴＰＢ的最佳剂量是推进剂总量的０．００６％￣０．０５％,在５０℃固化时间为７天。     

Development of LSM-based cathodes for solid oxide fuel cells based on YSZ films

In an attempt to achieve desirable cell performance, the effects of La_0.7Sr_0.3MnO₃ (LSM)-based cathodes on the anode-supported solid oxide fuel cells (SOFCs) were investigated in the present study. Three types of cathodes were fabricated on the anode-supported yttria-stabilized zirconia (YSZ) thin films to constitute several single cells, i.e., pure LSM cathode, LSM/YSZ composite by solid mixing, LSM/Sm_0.2Ce_0.8O_1.9 (SDC) composite by the ion-impregnation process. Among the three single cells, the highest cell output performance 1.25 W cm⁻² at 800 °C, was achieved by the cell using LSM/SDC cathode when the cathode was exposed to the stationary air. Whereas, the most considerable cell performance of 2.32 W cm⁻² was derived from the cell with LSM/YSZ cathode, using 100 ml min⁻¹ oxygen flow as the oxidant. At reduced temperatures down to 700 °C, the LSM/SDC cathode was the most suitable cathode for zirconia-based electrolyte SOFC in the present study. The variation in the cell performances was attributed to the mutual effects between the gas diffusing rate and three-phase boundary length of the cathode.     

Simulation of sintering kinetics and microstructure evolution of composite solid oxide fuel cells electrodes

A three-dimension (3D) kinetic Monte Carlo (kMC) model is developed to study the sintering kinetics and microstructure evolution of solid oxide fuel cell (SOFC) composite electrodes during the co-sintering processes. The model employs Lanthanum Strontium Manganite (LSM) – Yttria-stabilized Zirconia (YSZ) composites as the example electrodes but can be applied to other materials. The sintering mechanisms include surface diffusion, grain boundary migration, vacancy creation, and annihilation. A morphological dilation method is used to generate the initial LSM–YSZ compacts as the input structures for the kMC simulation. The three-phase boundary (TPB) length, porosity, and tortuosity factor of the composite cathodes are calculated during kMC sintering. Simulation results are compared with literature data and good agreement is found. Parametric study is conducted to investigate the effects of particle size, size distribution, and sintering temperature on sintering kinetics as well as the evolution of electrode microstructures. The kMC model is capable of simulating the initial and a part of intermediate sintering stages of SOFC electrodes by considering various sintering mechanisms simultaneously. It can serve as a useful tool to design and optimize the sintering processes for composite SOFC electrodes.     

The Tribological Properties of Polypropylene Composite Filled with DBD-Treated Carbon Fiber

Dielectric barrier discharges (DBD) in ambient air are used on carbon fiber to improve the carbon fiber surface activity. Carbon fibers with length of 75 um are placed into the plasma configuration. The tribological properties of polypropylene filled with untreated and DBD treated carbon fiber are comparatively investigated. Results show that DBD treatment greatly improve the friction and wear properties of carbon fiber reinforced polypropylene composite (CF/PP).