NONLINEAR DYNAMIC ANALYSIS OF A LAMINATED HYBRID COMPOSITE PLATE SUBJECTED TO TIME-DEPENDENT EXTERNAL PULSES

Nonlinear dynamic responses of a laminated hybrid composite plate subjected to time-dependent pulses are investigated. Dynamic equations of the plate are derived by the use of the virtual work principle. The geometric nonlinearity effects are taken into account with the von Kármán large deflection theory of thin plates. Approximate solutions for a clamped plate are assumed for the space domain. The single term approximation functions are selected by considering the nonlinear static deformation of plate obtained using the finite element method. The Galerkin Method is used to obtain the nonlinear differential equations in the time domain and a MATLAB software code is written to solve nonlinear coupled equations by using the Newmark Method. The results of approximate-numerical analysis are obtained and compared with the finite element results. Transient loading conditions considered include blast, sine, rectangular, and triangular pulses. A parametric study is conducted considering the effects of peak pressure, aspect ratio, fiber orientation and thicknesses.     

Synthesis,characterization, and photophysical properties of paraben substituted cyclotriphosphazenes with hydrophilic side groups

Abstract

In this study, five new paraben substituted cyclotriphosphazene compounds containing hydrophilic glycol groups were successfully synthesized. All synthesized cyclotriphosphazene compounds 1-10 were fully characterized via general spectroscopic techniques such as ¹H, ³¹P NMR and MALDI-TOF mass spectrometry. In addition, the investigations of the UV-vis absorption and fluorescence emission properties of the 1-10 carried out via absorption and fluorescence spectroscopies in different solvents. The absorbance bands of the all synthesized compounds 1-10 were observed at about 230–300?nm in all solvents studied. Furthermore, the highest fluorescence emission intensity of the compounds 1-10 was observed in tetrahydrofuran at about 312?nm and the lowest emission intensity was observed in chloroform. The synthesized molecules can be used as custom designed molecules to investigate the DNA binding properties in automatic biosensor device in our laboratories, since they carry hydrophilic glycol units for water solubility and paraben derivatives for DNA effecting properties.     

Effect of the inorganic salt on the electrical conductivity characteristics of lyotropic nematics

The effect of inorganic salt on temperature dependent changes of the electrical conductivity of N_d and N_c lyotropic nematic mesophases consisting of disc like and rod like micelles has been investigated. It has been found from the temperature dependence of the electrical conductivity that the lyotropic and thermotropic phase transitions shifted to lower temperatures by addition of NH₄Br. Addition of the salt stimulates the formation of oriented textures of N_d and N_c mesophases. This work has been supported by EGE-AFP:97 Fen 010 prj.     

Effect of YBa2Cu3O7-x thin films on the textures and orientational properties of liquid crystals

In the present work, the effect of thin films of YBa₂Cu₃O_7-x complex compound on the mesomorphic and orientational properties of thermotropic nematic liquid crystals has been studied. Homogeneous, stable and reproducible homeotropic and tilted oriented textures of nematic liquid crystals were obtained. The effect of YBa₂Cu₃O_7-x thin films on the morphologic, orientational and optical properties of thermotropic nematic liquid crystals are discussed.     

Conformational and electronic properties of N-methacryloyl-(L)-glutamic acid

Conformers of N-methacryloyl-(L)-glutamic acid (MAGA, C₉H₁₃NO₅) in the gas phase, benzene or methanol environment were searched by the density functional theory (DFT) and time-dependent DFT. Selected conformational isomers based on potential energy surface analysis were studied by considering the structural and electronic properties. B3LYP functional, and HF and MP2 levels were used with the 6-31+G(d,p), 6-311+G(3df,p) and aug-cc-pVDZ basis sets. We explored the effect of medium on the conformational preferences, UV spectra and frontier molecular orbitals of the conformers. The outcomes of this research will be useful for future studies including moieties analogous to MAGA.