This research is devoted to investigating the thermal buckling analysis behaviour of laminated composite plates subjected to uniform and non-uniform temperature fields by applying an analytical model based on a refined plate theory (RPT) with five unknown independent variables. The theory accounts for the parabolic distribution of the transverse shear strains through the plate thickness and satisfies the zero-traction boundary condition on the surface without using shear correction factors; hence a shear correction factor is not required. The governing differential equations and associated boundary conditions are derived by using the virtual work principle and solved via Navier-type analytical procedure to obtain critical buckling temperature. Results are presented for: uniform and linear cross-ply lamination with symmetry and antisymmetric stacking, simply supported boundary condition, different aspect ratio (a/b), various orthogonality ratio (E1/E2), varying ratios of coefficient of uniform and linear thermal expansion (α2⁄α1), uniform and linearly varying temperature thickness ratio (a/h) and numbers of layers on thermal buckling of the laminated plate. It can be concluded that this theory gives good results compared to other theories.
A new azo dye, 5,5-[1,2-phenylenebis(2,1-biazenediyl)]bis[8-quinolino], was synthesized by reacting the diazonium salt of o-phenylenediamine with 8-hydroxyquinoline. The ligand was subsequently used to prepare a series of metal complexes with V(IV), Fe(III), Cr(III), Mn(II), Mo(VI), and Ru(III). The ligand was characterized using 1H and 3C-NMR spectroscopy, while the metal complexes were analyzed using UV-Vis, FT-IR, and mass spectrometry, along with thermal analysis (TGA, DSC), (C.H.N.), conductivity measurements, magnetic susceptibility, and metal and chlorine content analysis, the results indicated that the ligand exhibits tetracoordination. The complexes predominantly formed octahedral geometries, except for the vanadium complex, which
... Show MoreThis paper reports a.c., d.c. conductivity and dielectric behavior of Ep-hybrid composite with12 Vol.% Kevlar-Carbon hybrid . D.C. conductivity measurements are conducted on the graded composites by using an electrometer over the temperature range from (293-413) K. It was shown then that conductivity increases by increasing number of Kevlar –Carbon fiber layers (Ep1, Ep2, Ep3), due to the high electrical conductivity of Carbon fiber. To identify the mechanism governing the conduction, the activation energies at low temperature region (LTR) and at high temperature region (HTR) have been calculated. The activation energy values for hybrid composite decrease with increasing number of fiber layers. The a.c. conductivity was measured over fr
... Show MoreEvery body has a size and mass that distinguishes it from others and makes it different from others. Some of these bodies are huge and large in size, and some are small and light in weight. Among these masses and bodies are some that are dealt with by their size and weight, each according to its quantity, weight, and cheapness. This is why they created quantities by which these weights and quantities could be estimated, so they used measures and weights for that. Objectives: The research aims to know some measures and weights, such as the wife’s maintenance, the amount of zakat, etc.I found it to be a widely spread topic, and widely used in the folds of jurisprudence. During my reading of jurisprudence books, I found jurists using many qu
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The goal of the research is to find the optimization in the test of the appropriate cross-over design for the experiment that the researcher is carrying out (under assumption that there are carry-over effects of the treatments) to posterior periods after the application period (which is often assumed to be the first period). The comparison between the double cross-over design and the cross-over design with extra period. The similarities and differences between the two designs were studied by measuring the Relative Efficiency (RE) of the experiment.
An experimental investigation of natural convection heat transfer from an isothermal horizontal,vertical and inclined heated square flat plates with and without circular hole, were carried out in two cases, perforated plates without an impermeable adiabatic hole "open core" and perforated plates with an impermeable adiabatic hole "closed core" by adiabatic plug. The experiments covered the laminar region with a range of Rayleih number of (1.11x106 ≤RaLo≤4.39x106 ), at Prandtle number (Pr=0.7). Practical experiments have been done with variable inclination angles from horizon (Ф=0o ,45o,90o,135oand 180o),facing upward (0o≤Ф<90o), and downward (90o
≤Ф<180o). The results showed that the temperature gradient increases whi