Graduate University of Advanced Technology

About: Graduate University of Advanced Technology is a education organization based out in Kerman, Iran. It is known for research contribution in the topics: Carbon paste electrode & Electrochemical gas sensor. The organization has 890 authors who have published 2169 publications receiving 31027 citations.

Chemical Stabilization of Some Heavy Metals in an Artificially Multi-Elements Contaminated Soil, Using Rice Husk Biochar and Coal Fly Ash

Abstract: A greenhouse experiment has been planned for this study to delineate the benefits of two types of rice husk biochars (namely B300 and B600 which are prepared at 300°C and 600°C, respectvely) and coal fly ash (CFA), as soil amendments, for decreasing the amount of some heavy metals (like Pb, Cd, Ni, Cr, and Cu) as well as mobility and phytoavailability in an artificially-calcareous multi-element-contaminated soil. The effect of soil amendment on heavy metals’ availability has been evaluated via sequential extraction experiment and phytoavailability of the plant. According to the results, among the studied amendments, B600 has had the highest positive effect on both dry matter yield in corn and heavy metals’ availability reduction in post-harvest soil samples (with the exception of Cr), compared to CFA and B300, due to the increasing specific surface area, CEC, and pH that promote heavy metals’ sorption in the soil through surface complexation and ion exchange mechanisms. Evaluation of heavy metals’ chemical forms in post-harvest soil samples indicates that addition of amendments has significantly decreased mobility factor of heavy metals (with the exception of Cr in CFA-amended soils). In general, application of three soil amendments to this polluted soil has considerable effect on the reduction of heavy metals’ availability and phytoavailability. However, among the studied amendments, B600 and CFA have had the maximum and minimum effect on heavy metals’ availability reduction, respectively.

Ligand-less in situ surfactant-based solid phase extraction for preconcentration of silver from natural water samples prior to its determination by atomic absorption spectroscopy

Abstract: A simple and rapid ligand-less in situ surfactant-based solid phase extraction method for preconcentration of silver from water samples is developed. In this method, a cationic surfactant containing a proper alkyl group (n-dodecyltrimethylammonium bromide) is dissolved in the aqueous sample and then a proper ion-pairing agent (ClO4−) is added. Due to the interaction between surfactant and ion-pairing agent, solid particles are formed and used for adsorption of silver carbonate. After centrifugation, the sediment is dissolved in 2.0 mL 1 M HNO3 in ethanol and then aspirated directly into the flame atomic absorption spectrometer. Variables affecting the extraction efficiencies such as pH, concentrations of surfactant and CO32−, ion pair concentration, and extraction time, are optimized. Under such conditions, the calibration curve is linear from 3 to 700 μg L−1. Detection limit is 1.1 μg L−1 with an enrichment factor of 37. The relative standard deviation for eight replicate measurements of 100 μg L−1 is 2....

Optical and Thermal Simulations of Photovoltaic Modules With and Without Sun Tracking System

Abstract: The experimental method is extensively used to determine the temperature of a photovoltaic (PV) module at different hours of a day. In this method, the module temperature is measured using a temperature sensor mounted on the back of PV module. However, the experimental measurements have high cost and are not applicable everywhere. In this study, an optical–thermal model was used to predict all the PV module layer temperatures in two cases: tilted toward the south and fixed on a two-axis sun tracker. The impact of accurate consideration of the wind velocity and the ambient temperature on the PV module temperature was the main strength of the present simulation. This was carried out testing several correlations for prediction of convection heat transfer coefficient in the modeling process. The front and back layer temperatures as well as the silicon (Si) layer temperature of PV module were separately determined. To verify the results of the simulation, the temperatures of four PV modules measured in four different locations of the world, namely, China, Germany, Australia, and Brazil, were used. The results showed that the present study predicts the temperature of PV module more accurately compared to the previous studies. It was also shown that the average temperature errors between the measured and the predicted temperatures relative to the maximum module temperature were 2.19%, 2.3%, and 2.85%, for Australia, Brazil, and Germany, respectively.

Stabilization of lead as affected by various amendments and incubation time in a calcareous soil

Abstract: The effect of different kinds of amendments including coal fly ash (CFA), municipal solid waste compost (MSWC), rice husk biochars prepared at 300°C (B300) and 600°C (B600), zero valent iron (Fe°) and zero valent manganese (Mn°) were evaluated to determine their ability to stabilize lead (Pb) in Pb-spiked soil. The Pb-spiked soils were separately incubated with amendments at the rates of 2 and 5% (W/W) for 45 and 90 days at 25°C. The efficacy of amendments treatment was evaluated by desorption kinetic experiment and sequential extraction producer. According to the results, with increasing time, considerable changes in distribution of chemical forms of Pb occurred and carbonate-bound fraction significantly decreased, while amorphous Fe-bound fraction significantly increased. The applied treatments efficiently decreased the mobility factor of Pb compared to control treatment. Application of Mn°, Fe°, CFA, MSWC, and B600 in soils significantly decreased Pb desorption rate with respect to control treatment. B...