Mountainous areas in the northern Pakistan are blessed by numerous rivers that have great potential in water resources and hydropower production. Many of these rivers are unexploited for their water resource potential. If the potential of these rivers are explored, hydropower production and water supplies in these areas may be improved. The Indus is the main river originating from mountainous area of the Himalayas of Baltistan, Pakistan in which most of the smaller streams drain. In this paper, the hydrology of the mountainous areas in northern Pakistan is studied to estimate flow pattern, long-term trend in river flows, characteristics of the watersheds, and variability in flow and water resource due to impact of climate change. Eight watersheds including Gilgit, Hunza, Shigar, Shyok, Astore, Jhelum, Swat, and Chitral, Pakistan have been studied from 1960 to 2005 to monitor hydrological changes in relation to variability in precipitation, temperature and mean monthly flows, trend of snow melt runoff, analysis of daily hydrographs, water yield and runoff relationship, and flow duration curves. Precipitation from ten meteorological stations in mountainous area of northern Pakistan showed variability in the winter and summer rains and did not indicate a uniform distribution of rains. Review of mean monthly temperature of ten stations suggested that the Upper Indus Basin can be categorized into three hydrological regimes, i.e., high-altitude catchments with large glacierized parts, middle-altitude catchments south of Karakoram, and foothill catchments. Analysis of daily runoff data (1960-2005) of eight watersheds indicated nearly a uniform pattern with much of the runoff in summer (June-August). Impact of climate change on long-term recorded annual runoff of eight watersheds showed fair water flows at the Hunza and Jhelum Rivers while rest of the rivers indicated increased trends in runoff volumes. The study of the water yield availability indicated a minimum trend in Shyok River at Yogo and a maximum trend in Swat River at Kalam. Long-term recorded data used to estimate flow duration curves have shown a uniform trend and are important for hydropower generation for Pakistan which is seriously facing power crisis in last 5 years.
Several types of nonbonded and chemically bonded composites of silica with linear and linear-nonlinear aramid polymers were prepared using the sol-gel process. The linear polyamide chains were synthesized by the reaction of a mixture of m-and p-phenylene diamines and terephthaloyl chloride in dimethyl acetamide. The nonlinear chains were prepared using 1,3,5-benzenetricarbonylchloride along with terephthaloyl chloride, thereby significantly increasing the average functionality of the monomers. These increased functionality chains were then endcapped with aminophenyltrimethoxysilane. Silica networks chemically bonded to the polyamide chains were produced by the addition of tetramethoxysilane to the aramid solution and its subsequent hydrolysis and condensation. The films cast from these solutions were yellow, and those containing up to 25 wt % silica were also transparent. Dynamic-mechanical thermal analysis was carried out to characterize interfacial bonding and interactions, in particular through the use of values of the glass transition temperatures T g of the polymers. The presence of the silica caused increases in T g , with the increases being largest for the composites in which there was strong interfacial bonding between the polymer chains and the ceramic silica phase.
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