Volumetric, Ultrasonic and Transport Properties of Binary Liquid Mixtures Containing Dimethyl Formamide at 303.15 K

Excess volumes （v^E）, ultrasonic velocities （u）, isentropic compressibility （△Ks） and viscosities （η） for the binary mixtures of dimethyl formamide （DMF） with 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-nitrotoluene and m-nitrotoluene at 303.15 K were studied. Excess volume data exhibit an inversion in sign for the mixtures of dimethyl formamide with 1,2- and 1,3-dichlorobenzenes and the property is completely positive over the entire composition range for the mixtures of dimethyl formamide with 1,2,4-trichlorobenzene, o-nitrotoluene and m-nitrotoluene. On the other hand, the quantity is negative for the mixtures of dimethyl formamide with chlorotoluenes. Isentropic compressibility （Ks） has been computed for the same systems from precise sound velocity and density data. Further, deviation of isentropic com- pressibility （△Ks） from ideal behavior was also calculated. AKs values are negative over the entire volume fraction range in all the binary mixtures. The experimental sound velocity data were analysed in terms of Free Length Theory （FLT） and Collision Factor Theory （CFT）. The viscosity data were analysed on the basis of corresponding state approach. The measured data were discussed on the basis of intermolecular interactions between unlike molecules.     

A Note on Quadrature Formulae for Cauchy Principal Value Integrals

The quadrature formulae of Chawla & Jayarajan (1975) havebeen extended in a simple manner for the numerical evaluationof the weighted Cauchy principal value integrals where , ß > –1 and a (–1, 1). The presentquadrature formulae give better approximate values for Cauchyprincipal value integrals than those in Chawla & Kumar (1979),and may also be used for the numerical evaluation of properintegrals      

Solid State Oxidative Aromatization of Hantzsch 1,4-Dihydropyridines to Pyridines Using Iodobenzene Diacetate or Hydroxy(tosyloxy)iodobenzene

An easy, safe, solvent-free and effective method for oxidative aromatization of Hantzsch 1,4-dihydropyridines catalyzed by hypervalent iodine (IBD and HTIB) to corresponding pyridine derivatives in high yields within short span of time. All reactions were carried out just by grinding the two reactants.     

Numerical and analytical investigations of thermosolutal instability in rotating Rivlin-Ericksen fluid in porous medium with Hall current

Numerical and analytical investigations of the thermosolutal instability in a viscoelastic Rivlin-Ericksen fluid are carried out in the presence of a uniform vertical magnetic field to include the Hall current with a uniform angular velocity in a porous medium. For stationary convection, the stable solute gradient parameter and the rotation have stabilizing effects on the system, whereas the magnetic field and the medium permeability have stabilizing or destabilizing effects on the system under certain conditions. The Hall current in the presence of rotation has stabilizing effects for sufficiently large Taylor numbers, whereas in the absence of rotation, the Hall current always has destabilizing effects. These effects have also been shown graphically. The viscoelastic effects disappear for stationary convection. The stable solute parameter, the rotation, the medium permeability, the magnetic field parameter, the Hall current, and the vis-coelasticity introduce oscillatory modes into the system, which are non-existent in their absence. The sufficient conditions for the non-existence of overstability are also obtained.     

On the number of generators of a projective module

In this article we give a bound on the number of generators of a finitely generated projective module of constant rank over a commutative Noetherian ring in terms of the rank of the module and the dimension of the ring. Under certain conditions we provide an improvement to the Forster–Swan bound in case of finitely generated projective modules of rank n over an affine algebra over a finite field or an algebraically closed field.     

Quantitation of 8-hydroxydeoxyguanosine in DNA by liquid chromatography/positive atmospheric pressure photoionization tandem mass spectrometry

A methodology has been developed and validated for quantifying 8-hydroxydeoxyguanosine (8-OHdG) in both commercial DNA and DNA isolated from livers of male Sprague-Dawley rats by liquid chromatography/positive atmospheric pressure photoionization tandem mass spectrometry. The analytical method conditions, including conditions for stabilizing 8-OHdG during complex nuclease P1 enzymatic digestion, were also evaluated. The limit of detection for 8-OHdG was 1.0 ng/mL (17.6 fmol on-column), and the linearity of the calibration curve was greater than 0.998 from 1.0 to 500 ng/mL. The intraday assay precision relative standard deviation (RSD) value for quality control (QC) samples was < or =5.59% with accuracies ranging from 91.84 to 117.61%. The interday assay precision (RSD) value was < or =1.76% with accuracies ranging from 91.84 to 116.67%. This method, combined with the LC/UV analysis of deoxyguanosine (dG), was used for determination of the levels of 8-OHdG/10(6) dG in DNA nuclease P1 enzymatic hydrolysates from both commercial DNA and rat liver DNA.     

Group graded associated ideals with flat base change of rings and short exact sequences

This paper deals with the study of behaviour of G-associated ideals and strong Krull G-associated ideals with flat base change of rings and behaviour of G-associated ideals with short exact sequences over rings graded by finitely generated abelian group G.     

Experimental measurement of effective atomic number of composite materials for Compton effect in the <Emphasis Type="Italic">γ</Emphasis>-ray region 280–1115 keV by a new method

In this paper, we report a new method to determine the effective atomic number, Z _eff, of composite materials for Compton effect in the γ-ray region 280–1115 keV based on the theoretically obtained Klein–Nishina scattering cross-sections in the angular range 50°–100° as well as a method to experimentally measure differential incoherent (Compton) scattering cross-sections in this angular range. The method was employed to evaluate Z _eff for different inorganic compounds containing elements in the range Z = 1–56, at three scattering angles 60°, 80° and 100° at three incident gamma energies 279.1 keV, 661.6 keV and 1115.5 keV and we have verified this method to be an appropriate method. Interestingly, the Z _eff values so obtained for the inorganic compounds were found to be equal to the total number of electrons present in the sample as given by the atomic number of the elements constituting the sample in accordance with the chemical formula of the sample. This was the case at all the three energies.