We investigate various dark energy models by taking into account the thermal effects induced from Hawking radiation on apparent horizon of Universe, for example near a finite-time future singularity. If density increases as Universe expands, Universe's evolution reaches singularity II type (or sudden singularity). The second derivative scale factor diverges but first remains finite. Quasi-de Si...

A significant challenge in motion planning is to avoid being in or near singular configurations, that is, configurations in joint space that result in the loss of the ability to move in certain directions in task space. A robotic system’s manipulability is reduced even in regions that are in close proximity to (i.e., neighbouring) a singularity. In this work we examine singularity avoidance in ...

this article addresses an efficient and novel method for singularity-free path planning and obstacle avoidance of parallel manipulator based on neural networks. a modified 4-5-6-7 interpolating polynomial is used to plan a trajectory for a spherical parallel manipulator. the polynomial function which is smooth and continuous in displacement, velocity, acceleration and jerk is used to find a pat...

We exhibit novel effects (absent in GR) of sources in massive gravity. First, we show that removing its ghost mode forces a field-current identity: The metric’s trace is locally proportional to that of its stress tensor; a point source implies a metric singularity enhanced by the square of the graviton’s range. Second, exterior solutions acquire spatial stress hair—their metric components depen...

ÐBy incorporating the e€ects of interfacial adhesion in the mechanics of rounded contact between two bodies, a new approach is proposed for the quantitative analysis of a wide variety of contact fatigue situations involving cyclic normal, tangential or torsional loading. In this method, conditions of ``strong'' and ``weak'' adhesion are identi®ed by relating contact mechanics and fracture mecha...

Fretting is a phenomenon that occurs at the contacts of surfaces that are subjected to oscillatory relative movement of small amplitudes. Depending on service conditions, fretting may significantly reduce the service life of a component due to fretting fatigue. In this regard, the analysis of stresses at contact is of great importance for predicting the lifetime of components. However, due to t...