Isotopic effects on non-linearity, molecular radius and intermolecular free length

Computation of non-linearity parameter (B/A), molecular radius (r _m) and intermolecular free length (L _f) for H₂O, C₆H₆, C₆H₁₂, CH₃OH, C₂H₅OH and their deuterium-substituted compounds have been carried out at four different temperatures, viz., 293.15, 303.15, 313.15 and 323.15 K. The aim of the investigation is an attempt to study the isotopic effects on the non-linearity parameter and the physicochemical properties of the liquids, which in turn has been used to study their effect on the intermolecular interactions produced thereof.     

The Phase Diagram for a Multispecies Left-Permeable Asymmetric Exclusion Process

Journal of Statistical Physics - We study a multispecies generalization of a left-permeable asymmetric exclusion process (LPASEP) in one dimension with open boundaries. We determine all phases in...     

Synthesis and characterization of aromatic polyazomethines bearing pendant pentadecyl chains

Aromatic diamine monomer viz., 4-(4′-aminophenoxy)-2-pentadecylbenzenamine containing pendant pentadecyl chain was synthesized starting from cashew nut shell liquid - a renewable resource material and was characterized by FTIR, ¹H and ¹³C NMR spectroscopy. A series of new (co) polyazomethines containing pendant pentadecyl chains and flexibilizing ether linkages was synthesized by polycondensation of 4-(4′-aminophenoxy)-2-pentadecyl benzenamine with commercially available aromatic dialdehydes viz., terephthaldehyde (TPA), isophthaldehyde (IPA) and varying mixture of TPA and IPA. Inherent viscosities and number average molecular weights of (co) polyazomethines were in the range 0.50-0.70 dL/g and 10,490-40-800 (GPC, polystyrene standard), respectively indicating formation of medium to reasonably high molecular weight polymers. (Co) polyazomethines containing pendant pentadecyl chains were found to be soluble in common organic solvents such as chloroform, dichloromethane, tetrahydrofuran, pyridine, m-cresol and could be cast into transparent and stretchable films from their solution in chloroform. (Co) polyazomethines were essentially amorphous in nature and the formation of loosely-developed layered structure was observed arising from the packing of pendant pentadecyl chains. Polyazomethines exhibited glass transition temperatures (T_g) in the range 21-48 °C. The observed depression of glass transition temperature could be ascribed to the “internal plasticization” effect of pentadecyl chains. The temperature at 10% wt loss (T₁₀), determined from TGA in nitrogen atmosphere of polyazomethines were in the range 434-441 °C indicating their good thermal stability.     

Nonlinear analysis of traffic continuum jams in an anisotropic model

This paper presents our study of the nonlinear stability of a new anisotropic continuum traffic flow model in which the dimensionless parameter or anisotropic factor controls the non-isotropic character and diffusive influence. In order to establish traff~c flow stability criterion or to know the critical parameters that lead, on one hand, to a stable response to perturbations or disturbances or, on the other hand, to an unstable response and therefore to a possible congestion, a nonlinear stability criterion is derived by using a wavefront expansion technique. The stability criterion is illustrated by numerical results using the finite difference method for two different values of anisotropic parameter. It is also been observed that the newly derived stability results are consistent with previously reported results obtained using approximate linearisation methods. Moreover, the stability criterion derived in this paper can provide more refined information from the perspective of the capability to reproduce nonlinear traffic flow behaviors observed in real traffic than previously established methodologies.     

Poly(terthiophene)s from copolymer precursors via solid‐state oxidative conversion

Herein, we report the synthesis of conducting poly (terthiophene)s using a side chain precursor polymer approach. Random copolymers were prepared by ring opening metathesis polymerization of two norbornylene monomers, one containing a pendant terthiophene group and the other containing a pendant acetate group. Solid‐state oxidative conversion of the terthiophene units was used to produce conductive polymers. Oxidative solid‐state conversion was successful for copolymers containing as little as 1 mol % of terthiophene comonomer. The electrical and optical properties of CPs were studied as a function of the amount of electroactive moiety, terthiophene (3T), present in the copolymer. The CPs were found to have conductivity varying between 10^?1 and 10^?4 S/cm depending on the precursor copolymer compositions. The CPs obtained from all precursors had no significant difference in their energy gaps and showed blue to orange color transitions when switching from the oxidized to the neutral states, respectively. The absorbance intensity at 426 nm for poly(3T) from the precursors fits the Beer–Lambert law corresponding to the range of initial 3T content in the precursor copolymer composition (from 1 to 100 mol %). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 756–763, 2010     

Sulfated tin oxide (SO4−2/SnO2): an efficient heterogeneous solid superacid catalyst for the facile synthesis of 2,3-dihydroquinazolin-4(1H)-ones

Research on Chemical Intermediates - A novel methodology for the facile synthesis of 2,3-dihydroquinazolin-4(1H)-ones by using sulfated tin oxide (SO4?2/SnO2) as a heterogeneous solid...     

Casimir effect modified surface energy of a nanocavity in homogeneous media

We determine the regularized van der Waals contribution to pressure within a spherical cavity of vapor in a homogeneous, isotropic, infinite medium. The spherical Hamaker function, , has been defined, for the first time, in contrast to the conventional Hamaker function for planar surfaces, . For the materials under consideration, the pressure inside the cavity varies as , where a is the radius of the cavity. For radii below a transition radius, the surface energy (or surface tension) becomes size dependent and could have important implications for homogeneous nucleation of nanosized bubbles in liquids, as well as cavitation of bubbles.