concentrations of six heavy metals including cr, mn, ni, pb, v and zn were determined in topsoil (from 47 grid cells), surface water (4 streams) and groundwater (8 wells and 4 qanats) from an agriculturalarea located at south part of the iranian capital, near the tehran oil refinery. concentrations of the elementswere measured using flame and flameless atomic absorption spectrometry. based on t...

We present a model for water uptake by plant roots from unsaturated soil. The model includes the simultaneous flow of water inside the root network and in the soil. It is constructed by considering first the water uptake by a single root, and then using the parameterized results thereby obtained to build a model for water uptake by the developing root network. We focus our model on annual plant...

We study interfacial water trapped between a sheet of graphene and a muscovite (mica) surface using Raman spectroscopy and ultrahigh vacuum scanning tunneling microscopy (UHV-STM) at room temperature. We are able to image the graphene-water interface with atomic resolution, revealing a layered network of water trapped underneath the graphene. We identify water layer numbers with a carbon nanotu...

Self-deployment of sensors with maximized coverage in Underwater Acoustic Sensor Networks (UWASNs) is challenging due to difficulty of access to 3-D underwater environments. The problem is further compounded if the connectivity of the final network is desired. One possible approach to this problem is to drop the sensors on the water surface and then move them to certain depths in the water to m...

an artificial neural network has been used to determine the volume flux and rejections of ca2+ , na+ and cl¯, as a function of transmembrane pressure and concentrations of ca2+, polyethyleneimine, and polyacrylic acid in water softening by nanofiltration process in presence of polyelectrolytes. the feed-forward multi-layer perceptron artificial neural network including an eight-neuron hidden la...

in order to determine hydrological behavior and water management of sepidroud river (north of iran-guilan) the present study has focused on stream flow prediction by using artificial neural network. ten years observed inflow data (2000-2009) of sepidroud river were selected; then these data have been forecasted by using neural network. finally, predicted results are compared to the observed dat...

a case study was carried out to see the impacts of shrimp culture on the surface (pond) and ground water (tube-well) quality in three coastal sub-districts of bagherhat sadar, rampal and morrelganj of bangladesh. the people of rampal (100%), morrelgonj (87.5%) and bagherhat (75.5%) expressed that salinity of both surface and ground water increased after shrimp culture, and water becomes more tu...

sustainability of water supply networks should be based on the risks of water hammer phenomenon. the purpose of this study is to provide a new approach to the analysis of water hammer phenomenon in the water supply network. by conventional methods, the damage because of water hammer is estimated based on the maximum pressure at nodes. however, during this phenomenon continuation and changing of...