In the general matter composition where the multiple scalar fields and the multiple perfect fluids coexist, in the leading order of the gradient expansion, we construct all the solutions of the nonlinear evolutions of the locally homogeneous universe. From the momentum constraint, we derive the constraints which the solution constants of the locally homogeneous universe must satisfy. We constru...

SUMMARY Achieving energy-efficient and high-speed dynamic walking has become one of the main subjects of research in the area of robotic biped locomotion, and passive dynamic walking has attracted a great deal of attention as a solution to this. It is empirically known that the convex curve of the foot, which characterizes passive–dynamic walkers, has an important effect on increasing the walki...

S. A. Aksenov, E. N. Chumachenko, I. V. Logashina, Higher School of Economics, Department of Mechanics and Mathematical Simulation, Moscow, Russia T. Kubina, VŠB – Technical University of Ostrava, Faculty of Metallurgy and Materials Engineering, Ostrava, Czech Republic The application of finite element simulation to the problem of roll pass design for round bar rolling is considered. Two roll p...

Pearlitic steels present very interesting mechanical properties when weldability requirements are not too severe. Thin gauge pearlitic steels require at least one intermediate annealing treatment between hot rolling and cold rolling. The globularised cementite in medium carbon steels provides then higher ductility, formability and machinability. On the other hand, in-line induction heating devi...

We have performed an experimental study, at very high resolution, of the wavelength selection and the evolution of rolling-grain ripples. A clear distinction is made between the flat sand bed instability and the ripple coarsening. The observation of the initial wavelength for the rolling-grain ripples is only possible close to the threshold for movement which imposes a constraint on the paramet...

We consider two examples of solutions of the equations of motion of scalar field theories with higher derivatives. These are the cosmology of the rolling tachyon and static spherically symmetric solutions of the scalar field in flat space. By requiring that the field equations always be hyperbolic and that the speed of propagation of the small fluctuations are not superluminal, we find constrai...

Finite element method simulations offer deep and detailed modeling of complex processes, but with high effort computation power time. For the special purpose flat rolling, a layer model was developed by Schmidtchen before based on classic elementary theory plasticity to inhomogeneous behavior significant lower at computation. This considered layers only as rigid or in plastic deformation state....