the quality of wastewater generated in any process industry is generally indicated by performance indices namely bod, cod and toc, expressed in mg/l. the use of toc as an analytica parameter has become more common in recent years especially for the treatment of industrial wastewater. in this study, several empirical relationships were established between bod and cod with toc using regression an...

erosion and sediment movement phenomena are one of the most complex issues in management of rivers drainage areas that in water projects are very important. that its measurement wants high time and cost. issue of surface runoff in river basin is a complex issue that human knowledge and understanding about its physical laws a viewpoint of some mathematical formulas is limited. in this study to i...

in order to decrease the risks associated with the management of urban watersheds, the use of proper methods is an essential task to estimate the runoff with a high degree of confidence. time of concentration is one of factors that impacts on peak discharge and runoff volume. the objective of this study is to select the best method among the empirical formulas for estimating the time of concent...

this publication uses a colorimetric method based on the absorbance spectra of dye solutions to improve on beer’s law when calculating the dye concentrations of a three-component mixture. the performance of the new method is compared with that of beer’s law evaluated at three wavelengths, and beer’s law evaluated at 16 wavelengths. colorimetric method gives the best prediction of dye concentrat...

This publication uses a colorimetric method based on the absorbance spectra of dye solutions to improve on Beer’s law when calculating the dye concentrations of a three-component mixture. The performance of the new method is compared with that of Beer’s law evaluated at three wavelengths, and Beer’s law evaluated at 16 wavelengths. Colorimetric method gives the best prediction of d...

This paper focuses on a hydraulic radius separation approach used to calculate the boundary shear stress in terms of bed and wall shear stress proposed in a trapezoidal channel. The average bed and sidewall shear stress in smooth trapezoidal open channels are derived after using Guo & Julien (2005) early equations taking a part of an investigation to cover both rectangular and trapezoidal chann...