Papers by Keyword: Geometric Mean

Abstract: The pultruded fiber reinforced polymer plastic (PFRP) is one of the most actively studied materials for structural member in construction industries. In this study, a buckling analysis of PFRP plate is conducted by two analysis methods. First, a buckling strength of PFRP plate is calculated by the exact orthotropic plate buckling analysis. Second, simplified buckling analysis for PFRP plate is conducted by using approximate orthotropic material properties. The approximate orthotropic material properties are geometric mean value of longitudinal and transverse material properties of original PFRP plate. As a result of buckling analysis, buckling strength of PFRP plate for each analysis method can be obtained. From the comparison between these results, advantages and disadvantages of each analysis method are discussed. In addition, it is also discussed whether the simplified buckling analysis method for PFRP plate is applicable for the design.

Abstract: Nowadays, through greater awareness of protecting the environment and sustainable development in organizations, the importance of recycling and returning of used product has increased in supply chain management. Selecting an appropriate recycler is a critical issue in an organization and it needs to trade off between multiple criteria. Selection criteria are related to organizational circumstances and they may be qualitative or quantitative with complexity and uncertainty in their nature. The purpose of this study is to determine the sustainability criteria for recycler selection and to suggest a fuzzy AHP model for choosing the best third party recycler. A comprehensive methodology is illustrated using a case study of a fast food restaurant chain in Malaysia.

Abstract: Chemical mechanical polishing (CMP) is a technique used in semiconductor fabrication for planarizing the top surface of an in-process semiconductor wafer. Especially, Post-CMP thickness variations are known to have a severe impact on the stability of downstream processes and ultimately on device yield. Hence understanding how to quantify and characterize this non-uniformity is significant step towards statistical process control to achieve higher quality and enhanced productivity. The main reason is that the non-uniformed interface between the wafer and the machine-pad adversely affects the polishing performance and ultimate surface uniformity. The purpose of this paper is to suggest a new measure that estimates the uniformity of wafer surface considering the difference of the amount of abrasion between the center and the edge. This new measure which is called the Coefficient of Uniformity is defined as the following ratio: Geometric Mean (GM) / Arithmetic Mean (AM). This metric can be evaluated regionally to quantify the non-uniformity on the wafer surface from the center to the edge. Further simulations show that this new measure is insensitive to shift of the wafer center and sensitive to shift of the wafer edge. This trend indicates that this new measure is a very useful to test the non-uniformity of wafer after CMP polishing.