Crack measurement after thermal shock is usually considered as a replacement because real-time observation of experiments difficult to achieve. This paper presents an experimental approach for displaying cracking using oxygen-acetylene flame and high-speed imaging translucent ceramic. We capture the crack propagation process, calculate speed, discuss effect sample size heat flux on propagation,...

A spectrum of weakly guided waves in the solar atmosphere at frequencies as high as 100 mHz (10 s period) has been detected with high-cadence solar image sequences from the Transition Region and Coronal Explorer (TRACE) spacecraft. The waves are visible in the TRACE 1600 far-UV passband and were detected as faint Å ridges in an energy spectrum produced by Fourier transformation of subfields of ...

Acoustic waves are generated by the convective motions in the solar convection zone. When propagating upwards into the chromosphere they reach the height where the sound speed equals the Alfvén speed and they undergo mode conversion, refraction and reflection. We use numerical simulations to study these processes in realistic configurations where the wavelength of the waves is similar to the le...

Large-scale molecular dynamics simulations and the reactive force field ReaxFF were used to study shock-induced initiation in crystalline pentaerythritol tetranitrate (PETN). In the calculations, a PETN single crystal was impacted against a wall, driving a shockwave back through the crystal in the [100] direction. Two impact speeds (4 and 3 km/s) were used to compare strong and moderate shock b...

Rolling bearings are one of the most widely used elements in industrial applications. Shock pulse method (SPM) has proven successfully as a diagnostic tool in determining bearing health. On the basis of illustrating the principle of SPM, this paper mainly concentrates on investigating the effect of different operating conditions on SPM. The shock pulse signals are derived from the wind turbine ...

Tho flare associated interplanetary (IP) shock of February 15-16, 1967 observed by Explorer 33 and Pioneer 7 is analyzed to yield an estimntion of the ecliptic plane geometry of the shock surface near 1 AU. These spacocraft were separated by 23° in heliocentric longitude and Pioneer 7 was at a distance of 1.12 AU from the sun. There was an 18.9 hour delay between the two observations. The estim...

Shock waves are steep wavefronts that are fundamental in nature, especially in high-speed fluid flows. When a shock hits an obstacle, or a flying body meets a shock, shock reflection/diffraction phenomena occur. In this paper, we show how several long-standing shock reflection/diffraction problems can be formulated as free boundary problems, discuss some recent progress in developing mathematic...

In this paper we present a new five particle species hybrid model for calculating cosmic ray particle transport and acceleration in a dynamic heliospheric environment. In particular the effects of solar cycle related changes in the solar wind speed on the heliospheric geometry, solar wind flow and cosmic ray distribution are discussed, when a polarecliptic asymmetry at the inner boundary is mod...

We consider degenerate viscous shock profiles arising in systems of two regularized conservation laws, where degeneracy here describes viscous shock profiles for which the asymptotic endstates are sonic to the associated hyperbolic system (the shock speed is equal to one of the characteristic speeds). Proceeding with pointwise estimates on the Green’s function for the linear system of equations...

The piston shock problem is a classical result of shock wave theory. In this work, the analogous dispersive shock wave (DSW) problem for a fluid described by the nonlinear Schrödinger equation is analyzed. Asymptotic solutions are calculated for a piston (step potential) moving with uniform speed into a dispersive fluid at rest. In contrast to the classical case, there is a bifurcation of shock...