In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was appl...In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was applied to produce the mixed modified binder. Laboratory tests were focused on the characterization of the properties of 45/80-55 CR binder with comparison to reference 50/70 and conventional polymer modified 45/80-55 bitumen. Based on conventional binder tests such as penetration, softening point and Fraass breaking point as well as BBR （bending beam rheometer） and DSR （dynamic shear rheometer） tests, rheological properties were investigated. For determination of stability of the polymer and crumb rubber, modified bitumen tube testing method was used. Based on the results analysis, improvement of the viscoelastic properties of polymer and crumb rubber modified bitumen was observed. Conventional properties and stability tests showed that it is possible to pass standard requirements for polymer modified bitumen. Mixed modification and terminal blend allow to use crumb rubber as a modifier with elimination of the separation of crumb rubber during transportation and storage at high temperature. In this paper, experience from filed sections with use of the asphalt mixture with new kind of modified bitumen is presented.展开更多
In October 1996, The Dhaka Stock Exchange （DSE） adopted trading halts for individual stocks, collectively known as ＂circuit breakers＂, to reduce the stock market volatility. This paper reviews the existing circuit...In October 1996, The Dhaka Stock Exchange （DSE） adopted trading halts for individual stocks, collectively known as ＂circuit breakers＂, to reduce the stock market volatility. This paper reviews the existing circuit breakers literature and developed five hypothesis--＂Magnet Effect＂, ＂Cool off-Heating （C-H） Effect＂, ＂Information Hypothesis＂, ＂Volatility Spillover Hypothesis＂ and ＂Trading Interferences Hypothesis＂--which could be tested empirically not only in the Dhaka Stock Exchange but any stock exchanges around the world. This paper also suggests most appropriate econometric models for empirical testing. GARCH for inter day data and Event Study methodology for intra day data. Moreover, to test the robustness non-parametric tests need to use along with parametric one. Considering the stock market bubbles in 1996, it has been found that it was optimal for the regulators to adopt this trading halt, but not for the market. It failed to protect the market. However, this might be the consequences of misconceptions about the purpose and effectiveness of circuit breakers. Despite many arguments contrary to this mechanism and absence of any conclusive empirical evidence for a fragile stock exchange like DSE, it may be useful sometimes to replace the ＂invisible hand of the marketplace＂ with the ＂visible hand of the market regulators＂.展开更多
文摘In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was applied to produce the mixed modified binder. Laboratory tests were focused on the characterization of the properties of 45/80-55 CR binder with comparison to reference 50/70 and conventional polymer modified 45/80-55 bitumen. Based on conventional binder tests such as penetration, softening point and Fraass breaking point as well as BBR （bending beam rheometer） and DSR （dynamic shear rheometer） tests, rheological properties were investigated. For determination of stability of the polymer and crumb rubber, modified bitumen tube testing method was used. Based on the results analysis, improvement of the viscoelastic properties of polymer and crumb rubber modified bitumen was observed. Conventional properties and stability tests showed that it is possible to pass standard requirements for polymer modified bitumen. Mixed modification and terminal blend allow to use crumb rubber as a modifier with elimination of the separation of crumb rubber during transportation and storage at high temperature. In this paper, experience from filed sections with use of the asphalt mixture with new kind of modified bitumen is presented.
文摘In October 1996, The Dhaka Stock Exchange （DSE） adopted trading halts for individual stocks, collectively known as ＂circuit breakers＂, to reduce the stock market volatility. This paper reviews the existing circuit breakers literature and developed five hypothesis--＂Magnet Effect＂, ＂Cool off-Heating （C-H） Effect＂, ＂Information Hypothesis＂, ＂Volatility Spillover Hypothesis＂ and ＂Trading Interferences Hypothesis＂--which could be tested empirically not only in the Dhaka Stock Exchange but any stock exchanges around the world. This paper also suggests most appropriate econometric models for empirical testing. GARCH for inter day data and Event Study methodology for intra day data. Moreover, to test the robustness non-parametric tests need to use along with parametric one. Considering the stock market bubbles in 1996, it has been found that it was optimal for the regulators to adopt this trading halt, but not for the market. It failed to protect the market. However, this might be the consequences of misconceptions about the purpose and effectiveness of circuit breakers. Despite many arguments contrary to this mechanism and absence of any conclusive empirical evidence for a fragile stock exchange like DSE, it may be useful sometimes to replace the ＂invisible hand of the marketplace＂ with the ＂visible hand of the market regulators＂.
