Dominant Mechanisms for Metal Removal from Acidic Aqueous Solutions by Cement Kiln Dust

Copper and zinc ions were removed from synthetic acidic aqueous solutions onto cement kiln dust (CKD) particles in a single component system. The objectives of this study were to: distinguish between adsorption and precipitation when both mechanisms are occurring simultaneously; define their individual contributions; and consequently, specify the dominant mechanism. This was achieved by conducting a new experimental procedure for the precipitation phase that depended on CKD leachate in combination with a derivation of a simultaneous adsorption-precipitation equation. High removal efficiencies, approaching 100?%, of the Cu and Zn ions, were attained. Precipitation was the dominant mechanism for removing low concentrations of these metals, while adsorption appears to be more significant in removal of high metal concentrations.     

Multidimensional appraisal of customer relationship management: integrating balanced scorecard and multi criteria decision making approaches

This paper presents a comprehensive integrative framework for measuring the performance of customer relationship management (CRM) system based on a detailed empirical study of 32 Iranian internet service provider (ISP) firms. At first, by an extensive literature review and experts who have real practical experiences in the field of CRM, appropriate key performance indicators (KPIs) based on four perspectives of balanced scorecard have been extracted. Then, due to the interdependency and feedback among these KPIs, multiple criteria decision making techniques are used to evaluate CRM performance. Specifically, this study first applies the decision making trial and evaluation laboratory approach to determine the interrelated relationships among criteria, and to find the crucial central and influential factors. Then, the analytical network process method is used to obtain the criterion weights. Finally, according to these previous results, the technique for order of preference by similarity to ideal solution method is adopted to analyze the CRM performance of 32 Iranian ISP firms. The results of this study illustrated that learning and growth is the most crucial influential perspective and it would influence on the other perspectives much more. Furthermore, indicators including organization capital, human capital, customer retention process, customer perceived value, and customer expansion process play an essential role in succeeding of CRM. The results of this study can provide a comprehensive insight for managers into discerning how and through which mechanisms CRM can create merits for the organizations.     

Eigenvalue approach for an unbounded medium with a spherical cavity based upon two-temperature generalized thermoelastic theory

The thermoelastic interaction in an unbounded medium with a spherical cavity is studied using two-temperature generalized thermoelasticity theory. The medium is assumed to be initially quiescent. The inner surface of the cavity is taken traction free and subjected to a thermal shock. By the Laplace transformation, the basic equations are expressed in the form of a vector-matrix differential equation, which is solved by an eigenvalue approach. Some comparison have been shown in figures to estimate the effect of the two-temperature parameter.     

Preparation, characterization and application of advanced isoconversional kinetics to epoxy/1,4-Bis(3-aminopropoxy) butane/MWCNT nanocomposite

A novel nanocomposite consisting bisphenol A diglycidyl ether/1,4-Bis(3-aminopropoxy) butane (1,4-APB)/multiwall carbon nanotube (MWCNT) was synthesized and characterized. Kinetics of the reaction was described by applying differential scanning calorimetry (DSC) data to isoconversional methods of Flynn-Wall-Ozawa (FWO), advanced isoconversional method of Vyazovkin, and non-linear integral isoconversional algorithm (NLN). It was found that at the presence of MWCNT the thermal decomposition temperature increased by rising the curing temperature and time. Data from dynamic mechanical thermal analysis (DMTA) showed that the glass transition temperature of the cured nanocomposite is 7 °C higher than that value found for the system without carbon nanotube. Scanning electron microscopy (SEM) was used to observe the fracture surface morphology and results indicated evidence of the interfacial interaction improvement and adhesion strength due to good dispersion of MWCNT.     

A four variable refined plate theory for nonlinear cylindrical bending analysis of functionally graded plates under thermomechanical loadings

In this paper we present a new application for a four variable refined plate theory to analyse the nonlinear cylindrical bending behavior of functionally graded plates subjected to thermomechanical loadings. This recent theory is based on the assumption that the transverse displacements consist of bending and shear components in which the bending components do not contribute toward shear forces and, likewise, the shear components do not contribute toward bending moments. The theory accounts for a quadratic variation of the transverse shear strains across the thickness, and satisfies the zero traction boundary conditions on the top and bottom surfaces of the plate without using shear correction factors. The material properties are assumed to vary continuously through the thickness of the plate according to a power-law distribution of the volume fraction of the constituents. The non-linear strain-displacement relations in the von Karman sense are used to study the effect of geometric non-linearity. The solutions are achieved by minimizing the total potential energy and the results are compared to the classical and the first-order theories reported in the literature. It can be concluded that the proposed theory is accurate and simple in solving the nonlinear cylindrical bending behavior of functionally graded plates.     

Stochastic models for transfer point location problem

The transfer point location problem has been introduced recently and for the case of minimax objective and planar topology, has only been studied for situations in which demand points are not weighted and have known coordinates. In this paper, we consider the case in which demand points are weighted and their coordinates have bivariate uniform distribution. Also, the problem is developed from a conceptual view and different distance measures are used to make models more applicable in real world situations. The problem is to find the best location for the transfer point such that the maximum expected weighted distance to all demand points through the transfer point is minimized. Depending on assumptions for uniform distributions, two models are considered, convexity conditions are discussed, properties of the optimal solution are obtained and methods to solve the problems are proposed. Finally, numerical examples are given.