Results from an experimental study concerning wave propagation in cementitious materials are presented in this paper. Narrow band pulses at several frequencies were introduced into specimens of cement paste, mortar and concrete allowing direct measurement of longitudinal wave velocities and amplitude for each frequency. It is shown that aggregate content play an important role in wave propagati...

In cancellous bone, longitudinal waves often separate into fast and slow waves depending on the alignment of bone trabeculae in the propagation path [1]. This interesting phenomenon becomes an effective tool for the diagnosis of osteoporosis because wave propagation behavior depends on the bone structure [2]. Nagatani et al. pointed that fast wave requires certain propagation distance for stead...

The purpose of this research is to study the reflection transverse waves in the GreenLindsay theory for kind of smart materials under initial stress and relaxation times effect. It is found that, for two dimensional model of thermo-piezoelectric material, there exists four waves namely, quasi-transverse wave (QS-mode), quasi-longitudinal wave (QP-mode), thermal wave ( -mode), and potential elec...

Nonlinear interactions of longitudinal waves were observed in a two-dimensional plasma crystal, i.e., a lattice composed of highly charged microspheres immersed in a plasma. The waves were launched by radiation pressure of a laser, and wave spectra in omega-k space were analyzed at various amplitudes of waves. At a sufficiently large amplitude of wave, the second and third wave harmonics satisf...

Neurocognitive and emotional regulatory deficits in substance users are often attributed to misuse; however most studies do not include a substance-naïve baseline to justify that conclusion. The etiological literature suggests that pre-existing deficits may contribute to the onset and escalation of use that are then exacerbated by subsequent use. To address this, there is burgeoning interest in...

conclusions religiosity has been used as a coping mechanism among blacks. religiosity may also be related to stress regulation among black youth. future studies need to test complex associations between race, sex, religiosity, chronic stress, coping, and function of hypothalamo-pituitary-adrenal (hpa). it is not known whether male black youth who are and those who are not religious differently ...

The condition for potential description of the wake waves, generated by flat or cylindrical driving electron bunch in cold plasma is derived. The two-dimensional nonlinear equation for potential valid for small values of that is obtained and solved by the separation of variables. Solutions in the form of cnoidal waves,existing behind the moving bunch at small values of vertical coordinate,are o...

We derive several kinetic equations to model the large scale, low Fresnel number behaviour of the generalized nonlinear Schrödinger (NLS) equation with a rapidly fluctuating random potential. Depending on the relative scale of fluctuation in the longitudinal and transverse directions, we classify the kinetic equations into the longitudinal, the transverse and the isotropic case. The principal a...