this study investigates propagation of mode i crack in b70 pre-stressed concrete sleepers by fracture mechanics approach. a new experimental analysis is done for notched b70 pre-stressed concrete sleepers with replica test and image analysis. a scanning electron microscope test (sem) and an image analysis are applied for the replica test in order to determine crack length and crack mouth openin...

initial cracks occur in high strength concrete sleepers for various reasons, such as shrinkage and wrong curing and long lifetime of over 50 years of sleepers. these cracks may lead to complete failure of the structure. in order to more accurately design the sleepers, fracture mechanics (not strength of materials) should be incorporated. in order to achieve this purpose, it is important to fore...

Over 50 years, a large number of research and development projects with respect to the use of cementitious and concrete materials for manufacturing railway sleepers have been significantly progressed in Australia, Europe, and Japan (Wang, 1996; Murray and Cai, 1998; Wakui and Okuda, 1999; Esveld, 2001; Freudenstein and Haban, 2006; Remennikov and Kaewunruen, 2008). Traditional sleeper materials...

In this paper the simulation and design of a quantum-film electro-optic switch is considered. This photonic device, is made from a new organic dipolar material called MNA or 2-methyl-4 nitroaniline, which possesses a high merit in comparison with it's inorganic counterparts (e.g. LiNbO3, GaAs, InSb, Quartz, etc). Montecarlo method is used to simulate the photon-it-electron interaction in this m...

introduction patients with palliated congenital heart disease may present later in life for major, non-cardiac surgical procedures. although alternative surgical techniques are now available for the treatment of the transposition of the great arteries (tga), an atrial level baffle (mustard or senning procedure) was previously performed. long-term adverse effects of the atrial level switch inclu...

Study Objectives To describe sleep duration patterns of adults over a 20-year period; to compare sociodemographic, lifestyle, and health characteristics across these patterns; and to relate the patterns to sleep quality. Methods The study population consisted of 3695 adults aged 20 to 59 years at baseline. Five measurements of self-reported sleep duration were used to compose seven patterns f...

Frank Sohn, on whom the following observations were made, was a hypnotic subject of Mr. Santanelli, a professional hypnotist. The boy had become so subjective that Mr. Santanelli proposed to keep him in a continuous hypnotic sleep for a week, without food or drink, and to use the seven-days sleeper as an additional attraction for his nightly exhibitions of hypnotism. Only two days before the ex...