Determining Effects of Wagon Mass and Vehicle Velocity on Vertical Vibrations of a Rail Vehicle Moving with a Constant Acceleration on a Bridge Using Experimental and Numerical Methods

Vibrations are vital for derailment safety and passenger comfort which may occur on rail vehicles due to the truck and nearby conditions. In particular, while traversing a bridge, dynamic interaction forces due to moving loads increase the vibrations even further. In this study, the vertical vibrations of a rail vehicle at the midpoint of a bridge, where the amount of deflection is expected to be maximum, were determined by means of a 1 : 5 scaled roller rig and Newmark-β numerical method. Simulations for different wagon masses and vehicle velocities were performed using both techniques. The results obtained from the numerical and experimental methods were compared and it was demonstrated that the former was accurate with an 8.9% error margin. Numerical simulations were performed by identifying different test combinations with Taguchi experiment design. After evaluating the obtained results by means of an ANOVA analysis, it was determined that the wagon mass had a decreasing effect on the vertical vibrations of the rail vehicle by 2.087%, while rail vehicle velocity had an increasing effect on the vibrations by 96.384%

Effects of dietary boron on performance, egg production, egg quality and some bone parameters in layer hens

In this study dietary boron at different doses (0, 25, 50, 100 and 200 mg/kg feed) was supplemented to layers from 4 to 64 weeks of age. There was no significant difference between treatments with respect of mortality, egg production, egg weight, egg mass and cracked eggs. Significant increases were observed in body weight as age rose. Body weight was not affected by dietary boron supplementation at 16 and 40 weeks of age. At 64 weeks of age boron additions of 50, 100 and 200 mg/kg to the diet resulted in significant lower body weights than that of the control group. Egg quality parameters; albumen height and Haugh units, were improved when 25 or 50 mg boron/kg diet was supplemented above the other treatments. Shape index, shell thickness, shell breaking strength were not affected by treatments, though 25 mg boron/kg diet tended to increase shell breaking strength. Tibia bone strength and phosphorus content in the tibia and femur were not affected by boron supplementation. Boron supplementation at 25 and 50 mg/kg significantly increased femur bone strength, and ash and calcium content of the tibia and femur bones. Concentration of boron in bone increased with the increase in dietary boron. Keywords: Calcium, phosphorus, fowls, bone strength, Haugh units, tibi

The hippocampus and orbitofrontal cortex jointly represent task structure during memory-guided decision making

The hippocampus, well known for its role in episodic memory, might also be an important brain region for extracting structure from our experiences in order to guide future decisions. Recent evidence in rodents suggests that the hippocampus supports decision making by representing task structure in cooperation with the orbitofrontal cortex (OFC). Here, we examine how the human hippocampus and OFC represent task structure during an associative learning task that required learning of both context-determined and context-invariant probabilistic associations. We find that after learning, hippocampal and lateral OFC representations differentiated between context-determined and context-invariant task structures. The degree of this differentiation within the hippocampus and lateral OFC is highly correlated. These results advance our understanding of the hippocampus and suggest that the hippocampus and OFC support goal-directed behavior by representing information that guides the selection of appropriate decision strategies