• Structural Engineering and Mechanics
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• 제86권6호
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• pp.731-738
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• 2023

This article presents an analytical approach to explore the bending behaviour of of two-dimensional (2D) functionally graded (FG) nanobeams based on a two-variable higher-order shear deformation theory and nonlocal strain gradient theory. The kinematic relations are proposed according to novel trigonometric functions. The material gradation and material properties are varied along the longitudinal and the transversal directions. The equilibrium equations are obtained by using the virtual work principle and solved by applying Navier's technique. A comparative evaluation of results against predictions from literature demonstrates the accuracy of the proposed analytical model. Moreover, a detailed parametric analysis checks for the sensitivity of the bending and stresses response of (2D) FG nanobeams to nonlocal length scale, strain gradient microstructure scale, material distribution and geometry.

• Membrane and Water Treatment
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• 제7권6호
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• pp.521-537
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• 2016

Laboratory-scale experiments were carried out to investigate the adsorption equilibrium, the adsorption kinetics and facilitated transport of two cationic dyes (Methylene Blue (MB) and Rhodamine B (RB)) on Polymer Inclusion Membrane (D2EHPA-PIM). Different adsorption isotherms (Freundlich, Langmuir and Temkin models) as well as kinetics models indicated that the adsorption process is spontaneous and exothermic. Under the optimal conditions, the adsorption removal efficiencies reach about 93% and 97% for MB and RB respectively. Different extraction values by D2EHPA-PIM were obtained for the two cationic dyes: MB is weakly extracted at pH 2.0 (E% = 18.7%) whilst E% = 82.4% was observed for RB at the same pH. This difference was exploited in a mixture containg both the 2 cationic dyes for the selective extraction of RB at pH 2. Desorption of both dyes was achieved from the membrane by using acidic aqueous solutions and desorption ratio up to 90% was obtained. The formulas of the extracted complexes by the PIMs were, determined by the method of slopes. The dyes transport was elucidated using mass transfer analysis where in it found relatively high values of the initial flux ($J_0$) as 41.57 and $18.74{\mu}mol.m^2.s^{-1}$ for MB and RB respectively.

• BMB Reports
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• 제43권11호
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• pp.744-749
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• 2010

The aim of this work was to determine whether intrinsically bent DNA sites are present at, or close to, the mammalian replication origins oriGNAI3 and oriB in the Chinese hamster AMPD2 locus. Using an electrophoretic mobility shift assay and in silico analysis, we located four intrinsically bent DNA sites (b1 to b4) in a fragment that contains the oriGNAI3 and one site (b5) proximal to oriB. The helical parameters show that each bent DNA site is curved in a left-handed superhelical writhe. A 2D projection of 3D fragment trajectories revealed that oriGNAI3 is located in a relatively straight segment flanked by bent sites b1 and b2, which map in previously identified Scaffold/Matrix Attachment Region. Sites b3 and b4 are located approximately 2 kb downstream and force the fragment into a strong closed loop structure. The b5 site is also located in an S/MAR that is found just downstream of oriB.

• Coupled systems mechanics
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• 제8권2호
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• pp.111-127
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• 2019

In this paper, we present a 2D multi-scale coupling computation procedure for localized failure. When modeling the behavior of a structure by a multi-scale method, the macro-scale is used to describe the homogenized response of the structure, and the micro-scale to describe the details of the behavior on the smaller scale of the material where some inelastic mechanisms, like damage or plasticity, can be defined. The micro-scale mesh is defined for each multi-scale element in a way to fit entirely inside it. The two scales are coupled by imposing the constraint on the displacement field over their interface. An embedded discontinuity is implemented in the macro-scale element to capture the softening behavior happening on the micro-scale. The computation is performed using the operator split solution procedure on both scales.

• Nuclear Engineering and Technology
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• 제45권6호
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• pp.707-720
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• 2013

We analyze piecewise homogenization with flux-weighted cross sections and preservation of averaged currents at the boundary of the homogenized domain. Introduction of a set of flux discontinuity ratios (FDR) that preserve reference interface currents leads to preservation of averaged region reaction rates and fluxes. We consider the class of numerical discretizations with one degree of freedom per volume and per surface and prove that when the homogenization and computing meshes are equal there is a unique solution for the FDRs which exactly preserve interface currents. For diffusion submeshing we introduce a Jacobian-Free Newton-Krylov method and for all cases considered obtain an 'exact' numerical solution (eight digits for the interface currents). The homogenization is completed by extending the familiar full assembly homogenization via flux discontinuity factors to the sides of regions laying on the boundary of the piecewise homogenized domain. Finally, for the familiar nodal discretization we numerically find that the FDRs obtained with no submesh (nearly at no cost) can be effectively used for whole-core diffusion calculations with submesh. This is not the case, however, for cell-centered finite differences.

• Membrane and Water Treatment
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• 제1권4호
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• pp.231-251
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• 2010

The sulfatation of chitosan, by reaction with chlorosulfonic acid under controlled conditions, allowed increasing the pH range of chitosan solubility. The biopolymer was characterized using FTIR and $^{13}C$-NMR spectroscopy, elemental analysis and titration analysis and it was tested for mercury recovery by polymer enhanced ultrafiltration (PEUF). In slightly alkaline conditions (i.e., pH 8) mercury recovery was possible and at saturation of the polymer the molar ratio $-NH_2$/Hg(II) tended to 2.6. Polymer recycling was possible changing the pH to 2 and the polymer was reused for 3 cycles maintaining high metal recovery. The presence of chloride ions influences metal speciation and affinity for the polymer and "playing" with metal speciation allowed using the PEUF process for mercury separation from cadmium; at pH 11 the formation of hydroxo-complexes of Hg(II) limits it retention. Cake formation reveals the predominant controlling step for permeation flux.

• ETRI Journal
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• 제28권2호
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• pp.257-259
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• 2006

In this letter, we will evaluate the performance degradation of a 40 km high-speed (40 Gb/s) optical system, induced by optical fiber variations of the chromatic dispersion induced by temperature changes. The chromatic dispersion temperature sensitivity will be estimated based on the signal quality parameters.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.205.1-205.1
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• 2008

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2012년도 자성 및 자성재료 국제학술대회
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• pp.100-100
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• 2012

• Kyungpook Mathematical Journal
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• 제49권2호
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• pp.211-219
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• 2009

We classify real hypersurfaces in complex projective space whose structure Jacobi operator satisfies a certain cyclic condition.