Dipotassium Hydrogen Phosphate Powder Catalyzed Synthesis of Alkyl 2-(2-Alkoxy-2-oxoethyl)dinaphtho[2,1-d:1,2-f][1,3]-dioxepin-2-Carboxylates from Stabilized Phosphorus Ylides in Solvent-Free Conditions

The protonation of the highly reactive 1:1 intermediates, produced in the reaction of triphenylphosphine and dialkyl acetylenedicarboxylates, by 1,1-binaphthyl-2,2′-diol leads to vinyltriphenylphosphonium salts, which undergo a Michael addition reaction to produce the corresponding stabilized phosphonium ylides. Dipotassium hydrogen phosphate powder was found to catalyze the conversion of the stabilized phosphonium ylides to alkyl 2-(2-alkoxy-2-oxoethyl)dinaphtho[2,1-d:1,2-f][1,3]-dioxepin-2-carboxylates under solvent-free conditions using microwave (0.6 KW, 3 min) and thermal (100°C, 60 min) conditions.     

Modeling and numerical simulation of blood flow using the theory of interacting continua

In this paper we use a modified form of the mixture theory developed by Massoudi and Rajagopal to study the blood flow in a simple geometry, namely flow between two plates. The blood is assumed to behave as a two-component mixture comprised of plasma and red blood cells (RBCs). The plasma is assumed to behave as a viscous fluid whereas the RBCs are given a granular-like structure where the viscosity also depends on the shear-rate.     

On the heat flux vector for flowing granular materials—part II: derivation and special cases

Heat transfer plays a major role in the processing of many particulate materials. The heat flux vector is commonly modelled by the Fourier's law of heat conduction and for complex materials such as non‐linear fluids, porous media, or granular materials, the coefficient of thermal conductivity is generalized by assuming that it would depend on a host of material and kinematical parameters such as temperature, shear rate, porosity or concentration, etc. In Part I, we will give a brief review of the basic equations of thermodynamics and heat transfer to indicate the importance of the modelling of the heat flux vector. We will also discuss the concept of effective thermal conductivity (ETC) in granular and porous media. In Part II, we propose and subsequently derive a properly frame‐invariant constitutive relationship for the heat flux vector for a (single phase) flowing granular medium. Standard methods in continuum mechanics such as representation theorems and homogenization techniques are used. It is shown that the heat flux vector in addition to being proportional to the temperature gradient (the Fourier's law), could also depend on the gradient of density (or volume fraction), and D (the symmetric part of the velocity gradient) in an appropriate manner. The emphasis in this paper is on the idea that for complex non‐linear materials it is the heat flux vector which should be studied; obtaining or proposing generalized form of the thermal conductivity is not always appropriate or sufficient. Copyright © 2006 John Wiley & Sons, Ltd.     

On the heat flux vector for flowing granular materials—Part I: effective thermal conductivity and background

Heat transfer plays a major role in the processing of many particulate materials. The heat flux vector is commonly modelled by the Fourier's law of heat conduction and for complex materials such as non‐linear fluids, porous media, or granular materials, the coefficient of thermal conductivity is generalized by assuming that it would depend on a host of material and kinematical parameters such as temperature, shear rate, porosity or concentration, etc. In Part I, we will give a brief review of the basic equations of thermodynamics and heat transfer to indicate the importance of the modelling of the heat flux vector. We will also discuss the concept of effective thermal conductivity (ETC) in granular and porous media. In Part II, we propose and subsequently derive a properly frame‐invariant constitutive relationship for the heat flux vector for a (single phase) flowing granular medium. Standard methods in continuum mechanics such as representation theorems and homogenization techniques are used. It is shown that the heat flux vector in addition to being proportional to the temperature gradient (the Fourier's law), could also depend on the gradient of density (or volume fraction), and D (the symmetric part of the velocity gradient) in an appropriate manner. The emphasis in this paper is on the idea that for complex non‐linear materials it is the heat flux vector which should be studied; obtaining or proposing generalized form of the thermal conductivity is not always appropriate or sufficient. Copyright © 2006 John Wiley & Sons, Ltd.     

Investigation of structure of milled wood and dioxane lignins of Populus nigra and Cupressus sempervirens using the DFRC method

In this study, derivatisation followed by reductive cleavage (DFRC) were used to investigate milled wood lignin (MWL) and dioxane lignin (DL) structures of Populus nigra and Cupressus sempervirens. After the DFRC reactions, the constituents obtained from these two kinds of lignin were recognised structurally using several chromatographic and spectral methods such as ¹³C NMR, GC-MS, and GPC. Comparative results showed that the dominant structural components of the two kinds of lignin are obtained from the cleavage of ??-O-4 bonds. The main component of DL and MWL of P. nigra is 4-hydroxy-3,5-dimethoxy-1-phenyl-??-hydroxypropene (syringyl structures). Also, some guaiacyl structures were observed. The dominant component identified in both lignins of C. sempervirens is 4-hydroxy-3-methoxy-1-phenyl-??-hydroxypropene (guaiacyl structures). The cleavage method has a good performance for both P. nigra and C. sempervirens and the results obtained are in good agreement with previously published data.     

A generalization of Reiner's mathematical model for wet sand

In this paper we modify the constitutive relation derived by Reiner (1945), to describe dilatancy in wet sand, by suggesting that the shear viscosity would depend on the shear rate and the volume fraction. We then look at the flow of a saturated densely packed bed of particles (with liquid in the pores) between two horizontal flat plates. We obtain exact solutions for a very special case.     

Synthesis and kinetics of the acid hydrolysis of the monothiooxalato-S,O-bis(ethylenediamine)chromium(III) complex

Cis-[Cr(en)₂(SC₂O₃)]Cl·H₂O has been synthesized by a new method involving the reaction of cis-[Cr(en)₂Cl₂]Cl with K₂SC₂O₃ at 60°C and the kinetics of the acidic aquation of this complex have been studied. The complex has been characterized by IR and electronic spectroscopic techniques. The aquation of the purified product was carried out at 30, 40 and 50°C in acidic media at constant ionic strength. The experimental result indicates a pH-dependent aquation of the compound in HCl solutions to yield H₂S and ethylenediamine. The plot of the rate of the reaction versus the square of the proton concentration, [H⁺]², produces a straight line giving the pseudo-first-order rate constant, k_obs. Activation energies were found to be proportional with the entropies in various acidic solutions. The “isokinetic temperature” of 285 K and the free energy of activation, ΔG‡ = 94.7 kJ mol⁻¹, were determined from the linear relationship. The results of experiments for the aquation of this compound suggest a mechanism through formation of a conjugate acid of an asymmetric atom, and the Cr---S bond cleavage is considered as the rate determining step.     

Falling film flow of a viscoelastic fluid along a wall

In this paper, we study the heat transfer in the fully developed flow of a viscoelastic fluid, a slag layer, down a vertical wall. A new constitutive relation for the stress tensor of this fluid is proposed, where the viscosity depends on the volume fraction, temperature, and shear rate. For the heat flux vector, we assume the Fourier's law of conduction with a constant thermal conductivity. The model is also capable of exhibiting normal stress effects. The governing equations are non‐dimensionalized and numerically solved to study the effects of various dimensionless parameters on the velocity, temperature, and volume fraction. The effect of the exponent in the Reynolds viscosity model is also discussed. The different cases of shear‐thinning and shear‐thickening, cooling and heating, are compared and discussed. The results indicate that the viscous dissipation and radiation (at the free surface) cause the temperature to be higher inside the flow domain. Copyright © 2013 John Wiley & Sons, Ltd.     

Flow of a non‐linear (density‐gradient‐dependent) viscous fluid with heat generation,viscous dissipation and radiation

In this paper, we study the flow of a compressible (density‐gradient‐dependent) non‐linear fluid down an inclined plane, subject to radiation boundary condition. The convective heat transfer is also considered where a source term, similar to the Arrhenius type reaction, is included. The non‐dimensional forms of the equations are solved numerically and the competing effects of conduction, dissipation, heat generation and radiation are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis of Bisindolylindeno[1,2-b]quinoxaline and Bisindolylindeno[3,4-b]pyrazine with Poly(N,N′-dibromo-N-ethylnaphthyl-2,7-disulfonamide)

Poly(N,N′-dibromo-N-ethylnaphthyl-2,7-disulfonamide) (PBNS) as novel reagent was synthesized. Bisindolylindeno[1,2-b]quinoxaline and bisindolylindeno[3,4-b]pyrazine derivatives were synthesized in a simple and efficient method from the three-component condensation reaction of indole, indane-1,2,3-trione, and diamine aromatic compounds by PBNS under solvent-free conditions at 80 °C in good to excellent yields, short reaction times, and a simple procedure for new derivatives.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications^® for the following free supplemental resource(s): Full experimental and spectral details.]