Seminar by Dr. Vu Thi Ngoc Anh and MSc. Vu Minh Duc

At 14:00, June 7, 2024, the lectures from Dr. Vu Thi Ngoc Anh and MSc. Vu Minh Duc takes place in meeting room B.

Dr. Vu Thi Ngoc Anh presents a talk entitled "Novel Cu(II), Ni(II), Zn(II), Cd(II), and Mg(II) complexes with a series of 2-arylhydrazono-1,3-dicarbonyl compounds. Synthesis, structure and spectroscopic characteristics"

Abstract:

A series of novel metal complexes of Cu(II), Ni(II), Zn(II), Cd(II), and Mg(II) with four N-heterocyclic derivatives of 2-arylhydrazono-1,3-dicarbonyl compounds were isolated and identified by FT IR, 1H NMR, EPR, and UV–Vis spectroscopy. The crystallographic data for two organic ligands as well as Mg (II) and Ni(II) complexes were obtained. It was indicated that the organic species exist in the form of hydrazo-tautomers. The Ni complex is monomeric and is characterized by the tridentate coordination of the ligand through a deprotonated N-atom of the hydrazo-fragment and two neighboring O-atoms of the carbonyl and deprotonated hydroxy-groups. In the case of the Mg complex the polymeric structure is observed with the additional coordination through the sulfamide group of the organic specie. Formation constants of the complexes in ethanol aqueous solutions were calculated and correlated with some physical characteristics of the metal cations. Structures of yet unstudied metal complexes were proposed based on quantum-chemical modeling at the DFT/B3LYP levelillustrates the efficacy of the proposed approaches. Additionally, some advantages and challenges in this research direction will be outlined.

MSc. Vu Minh Duc presents a talk entitled "Nonlinear dynamic responses of CNT-reinforced panels with complex curvature, piezoelectric layer, and CNT-reinforced stiffeners."

Abstract:

 In this paper, the nonlinear vibration and dynamic responses of the sinusoid, parabola, and cylindrical CNT-reinforced panels with piezoelectric layer stiffened by a CNT-reinforced stiffener system in uniform temperature change with a piezoelectric layer are presented. An improved homogenization technique for the x- or y-direction CNT-reinforced stiffener system is utilized to determine the total stiffnesses of the considered structures. The higher-order shear deformation theory (HSDT) in conjunction with the von Kármán nonlinearities is adopted to formulate the motion equations, while the stress function for complex curvature panels is estimated using the like-Galerkin procedure. The nonlinear equation of motion is acquired by utilizing the Lagrange function and Euler-Lagrange's equations. The numerical examples use the Runge-Kutta technique to acquire the nonlinear time-amplitude curves, and the critical dynamic buckling load is determined using the Budiansky-Roth criterion. These examples evaluate the effects of stiffeners, piezoelectric layer, material, and geometrical parameters on the nonlinear vibration and dynamic buckling responses of the panels.