background: this study was carried out to determination of heavy metals (cd, cr, cu, fe, pb, ni and zn) concentration in upstream and downstream of the entry of the wastewater (untreated urban, traditional slaughterhouse waste, leachate from solid wastes has accumulated in river and  run off waters flowing across the city ) to the tembi river. methods: samples were collected for 1 year, before ...

The complex hydrodynamics of water entry by a spinning sphere are investigated experimentally for low Froude numbers. Standard billiard balls are shot down at the free surface with controlled spin around one horizontal axis. High-speed digital video sequences reveal unique hydrodynamic phenomena which vary with spin rate and impact velocity. As anticipated, the spinning motion induces a lift fo...

The perturbations existing on a breaking wavefront can be potential explanation for the slamming pressure variability in wave impacts. Here, we investigate effect of these by forced vertical two-dimensional circular cylinder with constant downward velocity standing waves. Through experimental modelling and numerical simulation, force is measured several amplitudes wavelengths. phase tuned such ...

This paper explores the welfare implications of free entry when firms face known costs, but production costs are privately known. Upon entering, compete in prices to supply a homogeneous good. Our framework yields results that more nuanced than those literature on social efficiency and entry, where there is either insufficient or excessive for all parameter values. With asymmetric information, ...

The motion characteristics of trans-media vehicles during the water-entry process were explored in this study in an effort to obtain the optimal water-entry condition of the vehicle for developing a novel, single control strategy integrating underwater non-control and in-air control. A water-entry dynamics model is established by combining the water-entry motion characteristics of the vehicle i...