Dependence of microstructural, mechanical and electrical properties on growth rates in directional solidified Zn-Al-Bi eutectic alloy

Zn-5%Al-0.2%Bi（mass fraction） alloy was directionally solidified upward at a constant temperature gradient with a wide range of growth rates using a Bridgman-type directional solidification furnace. The eutectic spacings, microhardness, ultimate tensile strength and electrical resistivity for directionally solidified Zn-Al-Bi alloy were measured. Dependence of eutectic spacings, microhardness, ultimate tensile strength and electrical resistivity on growth rates was obtained by linear regression analysis. The results obtained in the present work for low growth rates（smaller than 450.0 μm/s） are in good agreement with experimental results obtained in previous work for directional solidified Zn-Al eutectic alloy with a similar growth rate but differs from the Jackson-Hunt eutectic theory and those obtained in previous experimental works at higher growth rates. The critical growth rate might be 450.0 μm/s for the Zn-Al-Bi eutectic alloy. From the plot of heat flow versus temperature, enthalpy of fusion, specific heat difference between liquid and solid phases and melting temperature for the Zn-Al-Bi alloy are found to be 112.55 J/g, 0.291 J/（g·K） and 660.20 K, respectively.

Corporate Governance Principles Introduced by the Capital Markets Board of Turkey and an Investigation About Internal Audit in Companies Listed on Borsa Istanbul

Today＇s global trends need to be clearly explained to enable the efficient functioning of capital markets for the purpose of the country＇s economic development. Promotion of a strong internal audit function plays a key role in assisting the board to discharge its governance responsibilities. The internal audit needs to exert its important function for refining corporate governance procedures, improving internal control, and strengthening risk management. The rules concerning internal auditing issued by the Banking Regulation and Supervision Agency, Capital Markets Board of Turkey, and other public societies have contributed to the development of internal auditing in Turkey. The Capital Markets Board of Turkey published “Communiqu6 Serial： IV, Noi 56 on Identification and Application of Corporate Governance Principles” （Official Gazette dated December 30, 2011, No. 28158）. In Part 4.2.4 of these principles, it was stated that “The board of directors supervise the efficiency of risk management and internal control systems at least once a year. Information about existence, operation, and efficiency of internal control and internal audit is given by annual report”. The objective of this study is to analyze the structure of internal audit function-related information on the annual reports of companies that are included in the Borsa Istanbul. Annual reports of 192 manufacturing companies listed on Borsa Istanbul were examined by content analysis method.