Herat University

About: Herat University is a education organization based out in Herat, Afghanistan. It is known for research contribution in the topics: Afghan & Population. The organization has 58 authors who have published 57 publications receiving 275 citations.

Hydrogeochemical characteristics and groundwater quality assessment for drinking and irrigation purposes in the Mazar-i-Sharif city, North Afghanistan

Abstract: The Mazar-i-Sharif city is part of the Balkh province, north of Afghanistan, and its groundwater resources are developed for water supply and irrigation purposes. The main lithological units consist chiefly of evaporite, conglomerate, sandstone, siltstone, and loess. In order to evaluate the quality of groundwater in the study area, 28 samples were collected and analyzed for various ions. Chemical indices like sodium adsorption ratio, the percentage of sodium, residual sodium carbonate and permeability index were calculated. Based on the analytical results, groundwater in the area is generally very hard, brackish, high to very high saline, and alkaline in nature. The abundance of the major ions is as follows: Cl− > HCO3− > SO42− > NO3− and Na+ > Ca2+ > Mg2+ > K+. The dominant hydrochemical facies of groundwater is the Na–Cl type, and alkalis (Na+, K+) and strong acids (Cl−, SO42−) are slightly dominating over alkali earths (Ca2+, Mg2+) and weak acids (HCO3−, CO32−). About 67% of the samples were showing a high concentration of nitrate, exceeding permissible limit of WHO (50 mg/l). The sources of NO3− in the study area are anthropogenic activities (domestic wastewater infiltration from the cesspits) and intense agricultural practices in nearby areas (Balkh district) of the city that utilize nitrogen and sulfate fertilizers. The chemical quality of groundwater is related to the dissolution of minerals, ion exchange, anthropogenic activities, and the residence time of the groundwater in contact with rock materials. The results of calculation saturation index by computer program PHREEQC show that nearly all of the water samples were supersaturated with respect to carbonate minerals (calcite and dolomite) and under-saturated with respect to sulfate minerals (gypsum and anhydrite). Assessment of water samples from various methods indicated that groundwater in the study area is chemically unsuitable for drinking and agricultural uses.

Seismic Energy Assessment of Buildings with Tuned Vibration Absorbers

Abstract: Seismic analysis and energy assessment of building installed with distributed tuned vibration absorbers (d-TVAs) are presented. The performance of d-TVAs is compared with single tuned vibration absorber (STVA) installed at the top of the building. The placements of the d-TVAs are based on the modal properties of the uncontrolled and controlled buildings. The governing equations of motion of the building with the STVA and d-TVAs are solved by employing Newmark’s integration method. Various energies under earthquake ground excitations are computed to study the effectiveness of using the STVA and d-TVAs. It is concluded that the use of the d-TVAs is the most competent because it effectively dissipates the seismic energy, and they are convenient to install requiring reduced space, as are placed at various floors.

Synthesis and characterization of chitosan nanoparticles containing teicoplanin using sol–gel

Abstract: Chitosan, as a natural polysaccharide, has a unique structure and multi-functional properties. One of the most prominent specifications of chitosan is high biocompatibility, good biodegradability, low toxicity and antibacterial and antiallergenicity properties. Chitosan has a high potential for controlled drug delivery. Therefore, investigating the loading capacity and release rate of chitosan at different conditions is important. By reducing particle size, chitosan has shown a high ability of teicoplanin loading due to its cationic property, which is important in this research. The aim of this study was to investigate chitosan nanoparticle potential for use in biomedical devices for drug delivery systems. Nanoparticles were prepared by ionic gelation with tripolyphosphate (TPP) ion, and the factors that affected chitosan nanoparticle size were investigated. The prepared samples were characterized using DLS, FTIR, TGA, DSC and XRD techniques. It is found at best condition with CS/TPP ratio of 2:1 nanoparticles were obtained at an average size of about 100 nm. The results confirmed that the drug (teicoplanin) loaded on the TPP cross-linked chitosan nanoparticles causes an increase in nanochitosan size and there was no interaction between teicoplanin and chitosan. Also, it is observed that 28.2% of teicoplanin was released in the first 10 h and the release is continued gradually to receive 37.4% in 100 h. Thus, it seems that chitosan nanoparticles mitigate the drug release and are suitable for sustained drug release.