Applied Mechanics and Materials Vols. 52-54

Abstract: When the school decides to implement the RFID campus-safety system, the administrators always encounter internal and external risk items or difficulties which they know even they don’t know. This study therefore proposes an analytic hierarchy model to help the administrators understand the critical risk factors influence the RFID campus-safety system initiation, and an aggregative risk degree is indicated which risk grade they are in. The importance weights of risk factors and possible occurrence ratings of four risk grade (high-risk, medium-risk, low-risk and none-risk) are determined by using consistent fuzzy preference relations. The relative priority weights of evaluators are taken into consideration at the same time and obtained by simple additive weighting method. By multiplying the importance weights of risk factors, possible occurrence ratings of risk grades and the relative priority weights of evaluators, the aggregative risk degree of implementing RFID campus-safety system.

Abstract: Based on the research of mechanism of energy conversion in blowing process, design and manufacture a couple of damper and expander. The experiment simulates hot blowing process with the damper and expander. Main paper properties and the fiber microstructure are examined. The results show that flash vaporization and its negative influence on pulp properties can be avoided when hot blowing using damp.

Abstract: This study proposes an analytic hierarchical prediction model based on consistent fuzzy preference relations to help the organizations become aware of the essential factors affecting the implementation oceanographic & meteorologic Integration Orchestrator. Pairwise comparisons are used to determine the priority weights of influential factors and the ratings of success or failure outcomes amongst decision makers. The subjectivity and vagueness in the prediction procedures are dealt with using linguistic terms quantified in an interval scale [0,1]. Then predicted success/failure values are obtained to enable organizations to decide whether to initiate knowledge management, inhibit adoption or take remedial actions to increase the possibility of successful oceanographic & meteorologic initiatives. This proposed approach is demonstrated with a real case study involving seven influential factors assessed by eleven evaluators solicited from a semiconductor engineering incorporation located in Taiwan.

Abstract: This paper explores a systematic method for optimal statistical tolerance allocation using the Lagrange multiplier method for minimizing manufacturing cost subject to constraints on dimensional chains and machining capabilities. The reciprocal power and exponential cost-tolerance models for statistical tolerancing are investigated for employing this method. The optimization problem is solved by applying the algorithmic approach. Especially, we further derive a closed-form expression of the tolerance optimization problem for reciprocal exponential cost-tolerance model by introducing the Lambert W function. For constrained minimization problems with only equality constraints, the optimum tolerance allocation can be obtained by solving simultaneous equations without further differentiating. An example is illustrated to demonstrate this approach. The result also shows that tolerances can be allocated quickly, economically and accurately using this method.

Abstract: This paper investigates a methodology and corresponding graph modeling of process planning for cylindrical machined parts with tolerancing. Methods and techniques for representing possible process plans, reducing the complexity and eliminating over-toleranced plans are developed. The method first maps each feature of a part into feasible finishing processes that are capable to achieve the specified tolerances associated with the feature. All possible process plans are then developed by expanding preceding processes of each finishing process. The expanded processes form a graph, or a forest, with processes as nodes and process sequence as links. Processes with same specifications can be further merged and pruned to reduce the complexity of the graph. Tolerance stack-up of each possible plan for simplified results is also further computed by tolerance chart such that over-toleranced plans are eliminated. As there are often many feasible plans for machining a part, the qualified plan that satisfies design specifications is achieved by traversal through the graph imposing tolerance chart. An example is also demonstrated to illustrate the approach and the model. The merit of this method is to employ a unified graph model for representing and reasoning.

Abstract: The top land of a piston normally known as the piston crown is an engine part that is continuously exposed to extreme temperature and pressure during combustion. For a compression ratio level, the compressed natural gas with a direct injection system (CNGDI) typically uses a range of compression ratio between gasoline and diesel engines, producing extremely high temperature and pressure which lead to high thermal stresses. Consequently, the piston crown is exposed to direct combustion due to the vertical movement of the piston, leading to various possible damages of thermal stresses. In contrast to a petrol fuelled internal combustion engine, natural gas combustion creates a dry condition in the combustion chamber, inducing cooling difficulties in the engine. Without good heat transfer, the piston crown materials will soon fail to withstand high temperature and operate effectively. Alternatively, any sort of insulation inside the combustion chamber such as applying ceramic coatings may protect the piston crown surface and affect the overall combustion process, as well as improving the engine performance and the exhaust emissions. By reducing the heat loss of a cylinder bore, a higher thermal efficiency of an engine can also be improved by applying a surface thermal insulation, namely; thermal barrier coating (TBC). Thus, in this study, a ceramic based TBC, yttria partially stabilised zirconia (YPSZ) coating was used to compare with conventional tin coated (Na2SnO3) and uncoated piston crown in terms of heat concentration. Moreover, a set of average value of combustion temperature of a CNGDI engine was selected. Detailed analyses using a finite element analysis (FEA) technique was utilised in order to determine the location of hotspots via distribution profiles of temperature. It was noted that the maximum heat flux of the uncoated piston crown was much higher than that of tin coated and YPSZ coated piston crown. Heat flux value reached about 62% of decrement due to lower conductivity levels of piston crown.

Abstract: The two kinds of bicycles of the power transmission types are derailleur type and built in gear hub type. Derailleur type is a simple structure but it is vulnerable to external contamination and impact. And it is impossible to shift from the quiescent state. Built in gear hub type is very strong about the external contamination and impact because working part did not expose to the outside. In this paper, a new design of a continuously variable transmission with built in gear hub type for bicycles was developed and simulated. Stress and displacement analysis in built in gear hub by using finite element method were performed in order to develop improved structure of CVT.

Abstract: A similarity-based filtering algorithm is proposed for multi-level matching. The algorithm consider all elements like service name, description information, input and output, reputation and effects respectively, cosine theorem and semantic distance are given in this paper to calculate their similarity. The aspects of the algorithm are as follows. It achieves a more comprehensive metrical scheme on the similarity between publishing service and request service from multiple stages and multiple perspectives in web service matching process. It judges whether the service preconditions match the effects based on description logic. Finally, it introduces reputation metrical scheme .In addition, the qualitative and quantitative analysis of the algorithm are given in this paper. The analysis results show that the Multi-level Matching Filtering Algorithm can obviously improve the recall ratio and precision ratio of Web service discovery.

Abstract: In order to research the mechanical properties and microstructure change regulation of cement-mixed soil under erosion environment, several experiments are carried out in laboratory. The changes of shear strength of cement-mixed soil are recorded under different erosion environments and in different erosion periods. Their corresponding photomicrographs are also shot to reveal the damage on cement-mixed soil under erosion environment. The results indicate that the shear strength of cement-mixed soil in erosion solutions is worse than the strength by the natural curing in the corresponding period. As erosion time increases the strength of cement-mixed soil dipped in , and solutions keeps on downtrend, whereas the strength of that dipped in unpolluted water and solution presents upward trend. The erosive effects of cement-mixed soil are mainly caused by and , meantime has more prominent erosive effect on cement-mixed soil than . Accompanying with stadium increasing quantitative parameters of microstructures are all varying markedly and have certain regulation which testifies the notable relativity between the shear strength and microstructural parameters. Liner regression methods are set up to indicate the relationship of shear strength indexes and microstructural parameters in the erosion environment.

Abstract: The mean idea of this paper is to present a new combinatorial solution technique for the controlled vibrating circle shell systems. Based on the classical results of the wave equations on circle domains, the trajectory is considered as a finite trigonometric series with unknown coefficients in polar coordinates. Then, the problem is transferred to one in which its unknowns are a positive Radon measure and some positive coefficients. Extending the underlying space helps us to prove the existence of the solution. By using the density properties and some approximation schemes, the problem is deformed into a finite linear programming and the nearly optimal trajectory and control are identified simultaneously. A numerical example is also given.