River bends are one of the common elements in most natural rivers, and secondary flow is important features bends. The perpendicular to main has a helical path moving towards outer bank at upper part river cross-section, inner lower cross-section. causes redistribution flow. Accordingly, this sediment transport by may lead formation typical pattern bend profile. It study understand order predic...

Mining nonmetallic sand, gravel, and river stones in a channel has previously caused damage to the itself surrounding environment. Technical studies are needed minimize mining channel. Ongkag Dumoga River is planned be location of non-metal material for gravel stone. The research method was carried out by geodesic mapping determine profile cross-section, hydrological analysis with return period...

It has been recognized that the arc statistics of gravitational lensing is a useful probe of the density profile of clusters of galaxies. We examine several systematic effects which are important in predicting the number of arcs, with particular attention to the difference between tangential and radial arcs. First we derive an analytic expression of the cross section for radial arcs taking acco...