Tandem arylation-reduction of acyl heterocycles. Convenient synthesis of benzyl heterocycles

Tandem arylation-reduction of a series of acyl heterocycles using phenyl-, 4-methylphenyl-, and 4-methoxy-phenyllithium reagents followed by lithium-ammonia-ammonium chloride reduction afforded the corresponding benzyl heterocycles. The acyl heterocycles surveyed in this study contained furan, 2,3-dihydro-4H-1-benzopyran, 4H-1-benzopyran, thiophene, 4,5,6,7-tetrahydrobenzo[b]thiophene, 2,3-dihydro-4H-1-benzothiopyran, and pyridine nuclei. All acyl heterocycles yielded the corresponding benzyl heterocycles except 2,3-dihydro-4H-1-benzothiopyran-4-one, which selectively cleaved during reduction to give the corresponding 2-(1-arylpropyl)benzenethiols.     

Explosives detection with electron‐rich polymers

The application of polymeric films as alarms for explosive materials is a critical issue these days as mandated by homeland security requirements. Amongst the multiple advantageous points of applying polymer films in this area is the fact that they are cheap material, so they can be applied on a broad scale for low cost. The basic idea of the current work is based on the fact that common explosives are electron deficient because of the existence of the nitro‐groups in their chemical structures, and this causes their high affinities towards electron rich materials to form charge‐transfer complex. Our endeavor is to trace any charge‐transfer complex formation, which would definitely cause a recognizable change in their physical properties. These changes in the polymers' physical properties could be utilized as alerts for the existence of explosive materials, especially if such changes could be incorporated into sophisticated electronic circuits that would give strong for traces of explosives. Copyright © 2013 John Wiley & Sons, Ltd.     

On the efficiency of price competition

We study the efficiency of price competition among multi-product firms in differentiated oligopolies. Under a general affine demand model, we show that total surplus (sum of industry profit and consumers’ surplus) under competition is at least 75% of the maximum total surplus achievable by a centralized planner. We also show, in contrast to more stylized oligopoly models, that price collusion can increase total surplus and that competition does not, in general, yield a Pareto efficient trade-off between industry profit and consumers’ surplus. However, the maximum deviation of total surplus from Pareto optimality is less than 10%. These results have implications regarding the effectiveness of current anti-trust regulations.     

Analysis of exergy and parametric study of a v-corrugated solar air heater

Solar air heater requires investigation for enhancement of solar energy conversion into heat. Different configurations with various artificial roughness geometries are proposed to date. In present study attention is paid on ways leading to more delivery of exergy by a v-corrugated solar air heater through parametric study. Effects of aspect ratio of the collector, inlet air temperature, mass flow rate per collector area etc. are studied.