Eigenfrequencies of symmetric planar frames with semi-rigid joints using weighted graphs

The main aim of this paper is to extend the recently developed methods for calculating the free vibration analysis of planar symmetric frames to include the effect of semi-rigidity of the joints. This is achieved by decomposing a symmetric weighted graph model into two submodels and using canonical forms in such a manner that the union of the eigenvalues of the submodels result in the eigenvalues of the entire model. Thus the eigenfrequencies of the frame is obtained in an efficient manner. Here, only the free vibration of frames with linear behavior is studied.     

Synthesis and in vitro anti-Toxoplasma gondii activity of a new series of aryloxyacetophenone thiosemicarbazones

Molecular Diversity - A new series of aryloxyacetophenone thiosemicarbazones 4a–q have been synthesized as anti-Toxoplasma gondii agents. All compounds showed significant inhibitory activity...     

Comparison between first-principles form factor and empirical form factor for transport theory in metals

It is demonstrated that currently available first-principles form factors are not sufficiently accurate for calculating the low-temperature electrical resistivity of metals. Moreover, it is shown that there is no basis for the recent suggestion, based on such an inadequate form factor, that phonon-drag effects may be neglected in the calculation of the low-temperature resistivity of potassium.     

Synthesis of 2-arylbenzimidazoles and 2-arylbenzothiazoles in both room temperature and microwave condition catalyzed by hexamethylenetetramine-bromine complex

One-pot condensation of 2-aminothiophenol or 1,2-phenylenediamine with different aldehydes has been catalyzed by hexamethylenetetramine-bromine(HMTA-Bromine) as new,available and effective catalyst.2-Arylbenzo thiazoles and 2-aryl benzimidazoles have been achieved in excellent yield and good purity.     

Regioselective bromination and iodination of aromatic substrates promoted by trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane

Selective and efficient bromination and iodination of aromatic compounds by ammonium bromide and ammonium iodide, respectively, under promotion of trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane have been explored. Mild reaction conditions, high selectivity and yield, and high reaction rate are some of the major advantages of this synthetic method.     

Olefins oxidation with molecular O2 in the presence of chiral Mn (III) salen complex supported on magnetic CoFe2O4@SiO2@CPTMS

In the present study, CoFe₂O₄@SiO₂@CPTMS nanocomposite was synthesized and the homogeneous chiral Mn‐salen complex was anchored covalently onto the surface of CoFe₂O₄@SiO₂@CPTMS nanocomposite. The heterogeneous Mn‐salen magnetic nanocatalyst (CoFe₂O₄@SiO₂@CPTMS@ chiral Mn (III) Complex) was characterized by different techniques including transmission electron microscopy (TEM), Fourier transform infrared (FT‐IR), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), powder X‐ray diffraction (XRD) and thermogravimetric analysis (TGA). Then, the aerobic enantioselective oxidation of olefins to the corresponding epoxide was investigated in the presence of magnetic chiral CoFe₂O₄@SiO₂@Mn (III) complex at ambient conditions within 90 min. The results showed the corresponding products were synthesized with excellent yields and selectivity. In addition, the heterogeneous CoFe₂O₄@SiO₂@ CPTMS@ chiral Mn (III) complex has benefits such as high selectivity and comparable catalytic reactivity with its homogeneous analog as well as mild reaction condition, facile recovery, and recycling of the heterogeneous catalyst.     

Oscillations in the frequency dependence of long-range correlations of waves

We predict new oscillations in the frequency dependence of the intensity autocorrelation functions of waves for a tube geometry. We have performed numerical simulations which clearly confirm the existence of new long-range correlations.