This research tracks the abnormal system operating conditions of the city of Asyut water supply network over an extended period. EPANET software was used to perform hydraulic and water quality analysis. Firstly, the effect of roughness variation with time on pressure head distribution and water quality through the network is simulated. Secondly, leakage due to failure of some pipes on the flow, pressure heads and water quality are investigated. Also the effect of closing some pipes in the network on pressure head and chlorine distributions is taken into consideration. Finally, the effect of changing the source of chlorine disinfection on water quality in the network is studied. The results indicate the following: (1) The increasing roughness of pipes can significantly increase the head losses through the network and consequently decrease the head at the end of network below the minimum limit. The variability in nodal pressures also has a significant effect on chlorine decay if the bulk wall reaction coefficient is taken to be dependent on the roughness of the pipe. (2) The failure of some pipes in the networks not only increases the consumed discharge in the network and decreases the pressure head but also changes the flow directions in some pipes through the network. (3) Closing a pipeline increases pressure in a region and decreases it at another and also changes the direction of flow in the network. This may affect the chlorine distribution through the network. (4) Chlorine disinfection from one source can significantly decrease the residual concentrations under the minimum limit in part of the network, while it can increase variability in nodal concentrations.

Nearly all water supply systems for high-rise buildings in Egypt include storage cisterns to feed the upper floors with cold water for different uses. Although these cisterns are the most important component in the distribution system, they are generally the least understood in terms of their effect on water quality. In this study, chlorine residual, algae genus and concentration, and pH value were measured before and after storage cisterns that exist above a 12-floor building in Assiut City, Egypt, to check their effect on water potability, through 48 h of observation. EPANET quality model is applied to simulate the chlorine residual and water age in the distribution system and storage cisterns through extended period simulations. The model is used to study the influence of the storage cisterns size and the turnover depth on residual chlorine decay and water age in the tanks. Results indicated that oversized storage cisterns can have negative impacts on water quality, including increased water age, reduced disinfectant residuals, and increased growth of disinfectant by-products (DBPs). However, there are other key roles that storage plays in the distribution system, e.g., security of supply during supply interruption and reserve storage for firefighting. Some of the microbiological and chemical effects of the cisterns on water quality have been investigated. DOI: 10 .1061/(ASCE)WR.1943-5452.0000132. © 2011 American Society of Civil Engineers.

Nearly all water supply systems for high-rise buildings in Egypt include storage cisterns to feed the upper floors with cold water for different uses. Although these cisterns are the most important component in the distribution system, they are generally the least understood in terms of their effect on water quality. In this study, chlorine residual, algae genus and concentration, and pH value were measured before and after storage cisterns that exist above a 12-floor building in Assiut City, Egypt, to check their effect on water potability, through 48 h of observation. EPANET quality model is applied to simulate the chlorine residual and water age in the distribution system and storage cisterns through extended period simulations. The model is used to study the influence of the storage cisterns size and the turnover depth on residual chlorine decay and water age in the tanks. Results indicated that oversized storage cisterns can have negative impacts on water quality, including increased water age, reduced disinfectant residuals, and increased growth of disinfectant by-products (DBPs). However, there are other key roles that storage plays in the distribution system, e.g., security of supply during supply interruption and reserve storage for firefighting. Some of the microbiological and chemical effects of the cisterns on water quality have been investigated. DOI: 10 .1061/(ASCE)WR.1943-5452.0000132. © 2011 American Society of Civil Engineers.

This research tracks the abnormal system operating conditions of the city of Asyut water supply network over an extended period. EPANET software was used to perform hydraulic and water quality analysis. Firstly, the effect of roughness variation with time on pressure head distribution and water quality through the network is simulated. Secondly, leakage due to failure of some pipes on the flow, pressure heads and water quality are investigated. Also the effect of closing some pipes in the network on pressure head and chlorine distributions is taken into consideration. Finally, the effect of changing the source of chlorine disinfection on water quality in the network is studied. The results indicate the following: (1) The increasing roughness of pipes can significantly increase the head losses through the network and consequently decrease the head at the end of network below the minimum limit. The variability in nodal pressures also has a significant effect on chlorine decay if the bulk wall reaction coefficient is taken to be dependent on the roughness of the pipe. (2) The failure of some pipes in the networks not only increases the consumed discharge in the network and decreases the pressure head but also changes the flow directions in some pipes through the network. (3) Closing a pipeline increases pressure in a region and decreases it at another and also changes the direction of flow in the network. This may affect the chlorine distribution through the network. (4) Chlorine disinfection from one source can significantly decrease the residual concentrations under the minimum limit in part of the network, while it can increase variability in nodal concentrations.

A conventional weir typically consists of an impermeable body constructed of concrete, since its primary functions are to heading up water and efficiently regulate flow. However, an impermeable body prevents the longitudinal movement of aquatic life and transportation of physical and chemical substances in water, eventually having a negative impact on the water environment. One of the advantages of gabions as a building material is that the motion of individual stones comprising the gabion is not of much concern. The wire mesh of the gabion basket serves to restrain any significant movement. Also, gabion weirs offer an alternative design that could be adopted for flash flood mitigation. In this study, a series of laboratory experiments was performed in order to investigate the flow over gabion weirs. For this purpose, two different gabion weir models were tested in two horizontal laboratory flumes of 10-m and 17-m length, 0.3-m width, and 0.3- and 0.5-m depth, respectively, for a wide range of discharge, upstream water depth, downstream water depth, weir height, weir length, and gabion filling gravel material size. The results of the gabion weir were compared with those of experiments carried out on solid weirs having the same dimension and it was found that there is a large deviation when the solid weirs equation is applied to gabion weirs
permeable weirs. So, using one of the existing solid weir flow formulas would lead to an erroneous calculated value. Multiple regression equations based on the dimensional analysis theory were developed for computing the discharge over gabion weirs for both free and submerged flow regimes. Also, equations were introduced for computing the discharge coefficient to be applied with the traditional solid weir equation.

This article presents a novel compactcircularly polarized antenna with wideband operation. The proposed antenna consists of a microstrip-line-fed printed monopole, a finite truncated ground, and a dielectric resonator (DR). Compared to the printed monopole antenna, the proposed DR-loaded antenna has an increased impedance bandwidth, a large axial ratiobandwidth, and a good realized gain across the desired frequency range. An antenna prototype is fabricated and experimentally tested. The measured antenna impedance match is better than _10 dB over 90% from 4.5 to 11.8 GHz frequency band and the 3-dB axial-ratio bandwidth is better than 35% covering the 5.4–7.65 GHz frequency band.