Broken rails are the most frequent cause of freight-train derailments in the United States. Consequently, reducing their occurrence is a high priority for the rail industry and the U.S. Federal Railroad Administration. Current practice is to periodically inspect rails to detect defects using nondestructive technology such as ultrasonic inspection. Determining the optimal rail inspection frequen...

Measures of the irregularity of chemical graphs could be helpful for QSAR/QSPR studies and for the descriptive purposes of biological and chemical properties, such as melting and boiling points, toxicity and resistance. Here we consider the following four established irregularity measures: the irregularity index by Albertson, the total irregularity, the variance of vertex degrees and the Collat...

The aim of this study was to compare the effects of grab rail position, orientation, and number of hands used on the kinetics of assisted sit-to-stand transfers. Participants were 12 able-bodied older adults between the ages of 69 and 88 years. While each one performed the sit-to-stand transfer, a motion analysis system with 9 cameras recording at 60 Hz tracked the 3-D trajectories of retrorefl...

The irregularity of a graph G is defined as the sum of weights |d(u) − d(v)| of all edges uv of G, where d(u) and d(v) are the degrees of the vertices u and v in G, respectively. In this paper, some structural properties on trees with maximum (or minimum) irregularity among trees with given degree sequence and trees with given branching number are explored, respectively. Moreover, the correspon...

The propagation of shear waves in an anisotropic fluid saturated porous layer over a prestressed semi-infinite homogeneous elastic half-space lying under an elastic homogeneous layer with irregularity present at the interface with rigid boundary has been studied. The rectangular irregularity has been taken in the half-space. The dispersion equation for shear waves is derived by using the pertur...

final step of rail manufacturing is cold rolling straightening process and it hassignificant effects on mechanical properties, straightness, flatness and development of residualstresses. measurement of residual stresses after straightening process is obligated by railmanufacturing standards. in the present investigation, an attempt has been made to evaluateresidual stresses after straightening ...

We analyze extensively the temporal properties of the train of spikes emitted by a simple model neuron as a function of the statistics of the synaptic input. In particular we focus on the asynchronous case, in which the synaptic inputs are random and uncorrelated. We show that the NMDA component acts as a non-stationary input that varies on longer time scales than the inter-spike intervals. In ...

Spontaneous motion of an oil droplet driven by nonequilibrium chemical conditions is reported. It is shown that the droplet undergoes regular rhythmic motion under appropriately designed boundary conditions, whereas it exhibits random motion in an isotropic environment. This study is a novel manifestation on the direct energy transformation of chemical energy into regular spatial motion under i...

Semi-regular phonological processes occur often in natural language. For example, rendaku voicing in Japanese fails to occur in a seemingly random fashion among roughly 16% of certain classes of compounds. This presents an analytical challenge for generative theories with exceptionless rules or categorical constraints: irregularity of any kind must arise within lexical representations, not the ...