Browsing by Subject "Waste disposal"

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    Artificial neural network models for predicting electrical resistivity of soils from their thermal resistivity
    (2010) Erzin Y.; Rao B.H.; Patel A.; Gumaste S.D.; Singh D.N.
    The knowledge of soil electrical and thermal resistivities is essential for several engineering projects such as laying of high voltage buried power cables, nuclear waste disposal, design of fluidized thermal beds, ground modification techniques etc. This necessitates precise determination of these resistivities, and relationship between them, which mainly depend on the soil type, its origin, compaction density and saturation. Such a relationship would also be helpful for determining one of these resistivities, if the other one is known. With this in view, efforts were made to develop artificial neural network (ANN) models that can be employed for estimating the soil electrical resistivity based on its soil thermal resistivity and the degree of saturation. To achieve this, measurements of electrical and thermal resistivities were carried out on different types soils compacted at different densities and moisture contents. These models were validated by comparing the predicted results vis-à-vis those obtained from experiments. The efficiency of these ANN models in predicting the soil electrical resistivity has been demonstrated, if its thermal resistivity is known. These ANN models are found to yield better results as compared to the generalized relationships proposed by the earlier researchers. © 2009 Elsevier Masson SAS. All rights reserved.
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    Investigation of strontium sorption onto Kula volcanics using Central Composite Design
    (2012) Kütahyali C.; Çetinkaya B.; Acar M.B.; Işik N.O.; Cireli T.
    In performance assessment studies, the uptake of the radioactive elements by rock formations play an important role in retarding their aqueous phase migration. Sorption studies of radionuclides have been conducted to obtain data on the distribution coefficient (K d) that is as an input parameter in the performance assessment of the geological disposal of radioactive wastes. In this work, sorption experiments were studied in a batch sorption system using Sr(NO 3) 2 solution on non-treated and HCl-treated Kula volcanics. The distribution coefficient (K d) values of Sr 2+ derived from batch experiments were used to evaluate the migration behavior of Sr 2+. Central Composite Design was used in the experiments. Sr sorption was studied as a function of pH, temperature, initial concentration of adsorbate and contact time. The results show that the K d values are higher at pH 7-9 which is the pH range of the natural waters. The kinetic data conformed better to the pseudo-second-order equation. Thermodynamic parameters ΔH°, ΔS° and ΔG° were estimated and these parameters show that adsorption is endothermic. The correlation coefficients indicate that the Langmuir model fits better for the strontium sorption onto non-treated and HCl-treated Kula volcanics with monolayer capacities as 2.04 and 1.72mg/g, respectively. © 2011 Elsevier B.V..