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Tutte’s Wheels-and-Whirls Theorem proves that if M is a 3-connected matroid other than a wheel or a whirl, then M has a 3-connected minor N such that |E(M)| − |E(N)| = 1. Geelen and Whittle extended this theorem by showing that when M is sequentially 4-connected, the minor N can also be guaranteed to be sequentially 4connected, that is, for every 3-separation (X, Y ) of N , the set E(N) can be ...

An essential element of a 3–connected matroid M is one for which neither the deletion nor the contraction is 3–connected. Tutte’s Wheels and Whirls Theorem proves that the only 3–connected matroids in which every element is essential are the wheels and whirls. In an earlier paper, the authors showed that a 3–connected matroid with at least one non-essential element has at least two such element...

This paper presents an analysis of the energy storage requirements for hybrid railway vehicles. Autonomous hybrid railway vehicles combine two power sources. The conventional diesel primemover is supplemented with power derived from an on-board energy storage device. The device is discharged during high power demand, and may be recharged through regenerative braking. The energy savings that are...

Wheel–rail impact loads generated by discrete wheel tread irregularities may result in high dynamic bending stresses the wheelset axle, leading to a decrease component life and an elevated risk for fatigue failure. In this paper, versatile cost-efficient method simulate vertical interaction between railway track, accounting generic distributions shapes of damage, is presented. The (comprising t...

The share of rail transport in world continues to rise. As the number trains increases, so does load on railway. rails are direct contact with loaded wheels. Therefore, it is more easily damaged. In recent years, domestic and foreign scholars have conducted in-depth research railway damage detection. weakest part track system, switches prone damage. Assessing predicting surface can improve safe...

We study the unwheeled rational Kontsevich integral of torus knots. We give a precise formula for these invariants up to loop degree 3 and show that they appear as colorings of simple diagrams. We show that they behave under cyclic branched coverings in a very simple way. Our proof is combinatorial: it uses the results of Wheels and Wheelings and new decorations of diagrams.

Abstract Block braked railway wheels are subjected to thermal and rolling contact loading. The loading results in high temperatures stresses which cause slow time dependent processes such as creep, relaxation static recovery of the wheel material. At same time, implies a very fast mechanical load application. This paper is focused on material modeling pearlitic steel for wide range rates at ele...