Rail wear has dramatic impact on track performance, ride quality and maintenance costs. The amount of rail wear is influenced by various elements among which geometric parameters play an important role. The amount of ...Rail wear has dramatic impact on track performance, ride quality and maintenance costs. The amount of rail wear is influenced by various elements among which geometric parameters play an important role. The amount of wear in Iran’s railway lines and its imposed maintenance costs oblige us to make modifications on the various geometrical parameters. In order to ensure the effectiveness of these changes, it is necessary to investigate these parameters and their effects on the wear. This research is aimed at studying the effects of different track geometrical parameters on the vertical and lateral wear by conducting a three phase field investigation. The first phase was carried out at the switches of a station, the second phase at a straight line, and the third at a curved line out of the station. The results obtained are analyzed and the role of each track geometrical parameter in the rail wear is discussed. Recommendations for prevention or reduction of rail wear are presented.展开更多
We study quintessence cosmology with an effective A-term in Lyra manifold. We consider three different models by choosing variable A depending on time, the Hubble parameter and the energy density of dark matter and da...We study quintessence cosmology with an effective A-term in Lyra manifold. We consider three different models by choosing variable A depending on time, the Hubble parameter and the energy density of dark matter and dark energy. Dark energy is assumed as quintessence which interacts with the dark matter. Using numerical analysis we investigate the behavior of cosmological parameters in three different models and compare our results with observational data. State-finder diagnostic is also performed for all models.展开更多
文摘Rail wear has dramatic impact on track performance, ride quality and maintenance costs. The amount of rail wear is influenced by various elements among which geometric parameters play an important role. The amount of wear in Iran’s railway lines and its imposed maintenance costs oblige us to make modifications on the various geometrical parameters. In order to ensure the effectiveness of these changes, it is necessary to investigate these parameters and their effects on the wear. This research is aimed at studying the effects of different track geometrical parameters on the vertical and lateral wear by conducting a three phase field investigation. The first phase was carried out at the switches of a station, the second phase at a straight line, and the third at a curved line out of the station. The results obtained are analyzed and the role of each track geometrical parameter in the rail wear is discussed. Recommendations for prevention or reduction of rail wear are presented.
文摘We study quintessence cosmology with an effective A-term in Lyra manifold. We consider three different models by choosing variable A depending on time, the Hubble parameter and the energy density of dark matter and dark energy. Dark energy is assumed as quintessence which interacts with the dark matter. Using numerical analysis we investigate the behavior of cosmological parameters in three different models and compare our results with observational data. State-finder diagnostic is also performed for all models.
