Effect of variable viscosity on the peristaltic transport of a Newtonian fluid in an asymmetric channel

The effect of variable viscosity on the peristaltic flow of a Newtonian fluid in an asymmetric channel has been discussed. Asymmetry in the flow is induced due to travelling waves of different phase and amplitude which propagate along the channel walls. A long wavelength approximation is used in the flow analysis. Closed form analytic solutions for velocity components and longitudinal pressure gradient are obtained. The study also shows that, in addition to the effect of mean flow parameter, the wave amplitude also effect the peristaltic flow. This effect is noticeable in the pressure rise and frictional forces per wavelength through numerical integration.     

The significance of reducing setup times/setup costs

Scheduling with setup times or setup costs plays a crucial role in todays modern manufacturing and service environments where reliable products/services are to be delivered on time. Scheduling activities profoundly depend on the times/costs required to prepare the facility for performing the activities. However, the vast majority of existing scheduling literature ignores this fact. We define and emphasize the importance, applications, and benefits of explicitly considering setup times/costs in scheduling research. Moreover, a review of the latest research on scheduling problems with setup times/costs is provided.     

Two highly unsymmetrical tetradentate (N3O) Schiff base copper(II) complexes: Template synthesis,structural characterization,magnetic and computational studies

Two new copper(II) complexes, [Cu₂(L¹)₂](ClO₄)₂ (1) and [Cu(L²)(ClO₄)] (2), of the highly unsymmetrical tetradentate (N₃O) Schiff base ligands HL¹ and HL² (where HL¹ = N-(2-hydroxyacetophenone)-bis-3-aminopropylamine and HL² = N-(salicyldehydine)-bis-3-aminopropylamine) have been synthesised using a template method. Their single crystal X-ray structures show that in complex 1 two independent copper(II) centers are doubly bridged through phenoxo-O atoms (O1A and O1B) of the two ligands and each copper atom is five-coordinated with a distorted square pyramidal geometry. The asymmetric unit of complex 2 consists of two crystallographically independent N-(salicylidene)-bis(aminopropyl)amine-copper(II) molecules, A and B, with similar square pyramidal geometries. Cryomagnetic susceptibility measurements (5–300 K) on complex 1 reveal a distinct antiferromagnetic interaction with J = ?23.6 cm^?1, which is substantiated by a DFT calculation (J = ?27.6 cm^?1) using the B3LYP functional. Complex 1, immobilized over highly ordered hexagonal mesoporous silica, shows moderate catalytic activity for the epoxidation of cyclohexene and styrene in the presence of TBHP as an oxidant.     

A short proof for Arnold’s Theorem on the SFT-property

Rendiconti del Circolo Matematico di Palermo Series 2 - We give a short proof for one main part of Arnold’s Theorem on the SFT-property, namely, if A is a non-SFT ring, then there exists an...     

Kinetics of acid degradation of proton pump inhibitors in the presence of a thiol

An in vitro investigation of the kinetics of the complex system of acid‐catalyzed conversions and subsequent reactions of proton pump inhibitors (PPIs; omeprazole, lansoprazole and pantoprazole) was carried out using differential pulse polarography at the static mercury drop electrode. Reactions were investigated in the presence of 2‐mercaptoethanol, in solutions buffered to pH values ranging from 2.0 to 5.0. The first‐order reaction network was proposed for all conversions. The rate of degradation of PPIs and subsequent reactions with 2‐mercaptoethanol were found to follow the following general order: lansoprazole > omeprazole > pantoprazole. The rate of conversion of PPIs into sulfenic acid was found to be directly dependent on the basicity of benzimidazole nitrogen of PPIs, which determines the electrophilic reactivity of the adjacent carbon (C2). The rate of conversion of the sulfenic acid of PPIs into the disulfide (the inhibition reaction) was found to be dependent on the electrophilicity of the sulfur atom of the sulfenic acid. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 498–506, 2009