Vibration testing, combined with a numerical method, is a potential alternative approach for determining elastic constants of materials because of its nondestructive characteristic, single test, and producing average properties. To simplify the modeling processes and to find better results, the numerical method of combining finite element analysis and a hybrid genetic algorithm is proposed to inversely determine the elastic constants from the vibration testing data in this work. As verified from the available data of literatures, the repeatability and accuracy of the proposed inverse determination method are confirmed. Four composite specimens with different stacking sequence and thickness are used to determine their elastic constants. As applied to obtain the four or five elastic constants of composite materials, the performance of the proposed method is excellent. To obtain the four elastic constant for thin composite plates, it is better to use unidirectional and thick enough laminates. To determine the five elastic constants for thick composite plates, it is suggested to use unidirectional laminates with the length‐to‐thickness ratio less than or equal to 50. To conquer the effect of measurement error or missing frequencies, it is necessary to carefully exclude these frequencies in the objective function, and reasonable results could be obtained by the proposed method. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

With ridge vents that are commonly used in building ventilation applications as the research object, this study analyzed how design parameters affect the efficiency of thermal buoyancy-driven ventilation induced by ridge vents through computational fluid dynamics (CFD). The design parameters of ridge vents include the width S, height H, and eave overhang E. In consideration of engineering practices, the parameter ranges were set as follows: S = 1.2, 1.8, 2.4, and 3 m; H = 0.3, 0.6, 0.9, and 1.2 m; and E = 0, 0.3, and 0.6 m. The results show that when a ridge vent is under buoyancy-driven ventilation, the height H serves as the dominant design parameter. Correlation equations of the induced ventilation rates with the relevant ridge vent design parameters are provided.

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The purpose of this study is employing literature review, in-depth interviews, and the KJ method to uncover early stories of Hualien Sugar Factory, Taiwan through interviews with elders, categorizing the stories and analyzing their distinctiveness, and adapting and constructing them as historical and cultural textbooks for guided tours. For the result of this study, early local stories can be grouped into seven categories-stories from sugarcane fields, memories of life on sugar factory premises, memories at Dajin Elementary School, life outside the factory, life before and after the war, accidents and death of family, and employees of different identities.