• Korean Journal of Soil Science and Fertilizer
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• v.28 no.3
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• pp.218-226
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• 1995

Ion exchange equilibria in bulk and rhizosphere soil collected from peach seedlings were studied to find exchange equations that could be used in chromatographic models dealing with movement and distribution of fertilizer ammonium and exchangeable cations in soil profiles. Soil samples were equilibrated with mixtures of $NH_4Cl$, KCI, and $CaCl_2$ solutions and then extracted with $Sr(NO_3)_2$ solution to determine exchangeable cation compositions at equilibrium. Exchange data were fitted to Vanselow's, Gapon's, and Kerr's equations, but those formulations did not adequately describe the equilibria. An empirical equation of the form : ${\frac{\alpha_i^m}{a_j^n}}=K{\frac{(iX)^{mPi}}{(jX)^{nPj}}}$ which has an exponent on each of the exchangeable cation concentrations could describe the equilibria very well over the range of treatments. In this equation ${\alpha}^i$ and ${\alpha}^j$ are activities of cation i and j with valences m and n respectively. (iX) and (jX) are concentrations of exchangeable cations. Mole or equivalent fractions can be considered as the exchangeable ion concentration unit. Arbitrary constants $P_i$ and $P_j$, and distribution coefficient K can be found with multiple regression for the logarithmic form of the equation.

• Advances in materials Research
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• v.12 no.3
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• pp.243-261
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• 2023

This study aims to analyze the mechanical buckling behavior of a single-walled carbon nanotube (SWCNT) integrated with a one-parameter elastic medium and modeled as a Kerr-type foundation under a longitudinal magnetic field. The structure is considered homogeneous and therefore modeled utilizing the nonlocal first shear deformation theory (NL-FSDT). This model targets thin and thick structures and considers the effect of the transverse shear deformation and small-scale effect. The Kerr model describes the elastic matrix, which takes into account the transverse shear strain and normal pressure. Using the nonlocal elastic theory and taking into account the Lorentz magnetic force acquired from Maxwell relations, the stability equation for buckling analysis of a simply supported SWCNT under a longitudinal magnetic field is obtained. Moreover, the mechanical buckling load behavior with respect to the impacts of the magnetic field and the elastic medium parameters considering the nonlocal parameter, the rotary inertia, and transverse shear deformation was examined and discussed. This study showed useful results that can be used for the design of nano-transistors that use the buckling properties of single-wall carbon nanotubes(CNTs) due to the creation of the magnetic field effect.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.93-97
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• 1988

The physico-chemical properties of clay minerals(Kaolinite, Montmorillonite) and the competitive adsorption of various cations in them were investigated as a basic research for the development of clean and hygienic water from hard and contaminated water. The cation adsorption forces of various cations in two clay minerals were high in the order of $Ca^{{+}{+}}$ > $Mg^{{+}{+}}$ > $K^+$ > $Na^+$, and the orders of cation selectivity coefficients(K) in Montmorillonite, calculated by Kerr's equation, were $^KCa^{{+}{+}}/K$ > $^KMg^{{+}{+}}/K$, $^KCa^{{+}{+}}/Mg$ > $^KK^+/Mg$. The amount of adsorbed cations was most high in Na-saturated Montmorillonite among several samples. So, in order to more effectively remove various divalent cations in hard and contaminated water, Na-saturated Montmorillonite is most desirable.