Photoinduced Bending of Single Crystals of a Linear Bis-Olefin via Water-Templated Solid-State [2+2] Photopolymerization Reaction

The single crystals of two structural isomers of bis-olefinic molecules were shown to have contrasting properties in terms of their photoreactivity: one exhibits an excellent ability to form polymers, accompanied with bending of crystals upon irradiation, while the other is photostable. The photoreactive crystal is a first example in which [2+2] polymerization leads to bending of the crystals, with implications for the design of photoactuators. The hydrate formation ability of one of these molecular isomers promotes the solid-state reactivity in its crystal, as the H₂O molecules act as a template to bring the olefin molecules into the required arrangement for [2+2] polymerization. Further, the crystals of the polymer exhibited better flexibility and smoothed surfaces compared to those of the monomers. In addition, under UV-light the diene emits bluish violet light while the polymer emits green light, indicating that the luminescence property can be tuned through photoirradiation.     

Natural frequencies of rotating twisted beams: a perturbation method based approach

Meccanica - Structures such as turbomachinery blades, industrial fans, propellers, etc. can be modeled as twisted beams. The study of dynamics of these structures is vital as operational failure of...     

One‐shot pseudo‐time method for aerodynamic shape optimization using the Navier–Stokes equations

This paper presents a numerical method for aerodynamic shape optimization problems in compressible viscous flow. It is based on simultaneous pseudo‐time stepping in which stationary states are obtained by solving the pseudo‐stationary system of equations representing the state, costate and design equations. The main advantages of this method are that it blends in nicely with previously existing pseudo‐time‐stepping methods for the state and the costate equations, that it requires no additional globalization in the design space, and that a preconditioner can be used for convergence acceleration which stems from the reduced SQP methods. For design examples of 2D problems, the overall cost of computation can be reduced to less than 2 times the forward simulation runs. Copyright © 2011 John Wiley & Sons, Ltd.     

Chemoenzymatic asymmetric synthesis of fluoxetine,atomoxetine, nisoxetine,and duloxetine

The asymmetric synthesis of two well-known anti-depressant drugs, fluoxetine and duloxetine has been accomplished in a chemoenzymatic manner. The main highlight of the synthesis is the enantioselective cyanohydrin formation by a plant (R)-HNL (hydroxynitrile lyase). The enantiopure cyanohydrins are then synthetically manipulated into the above two drug molecules and two of their structural analogues, atomoxetine and nisoxetine.     

Induced Correspondence of a Local π‐Aromatic Sextet in Heteroannulenes: Synthesis and Characterization

Acid‐catalyzed [3+3] condensation reactions of two hitherto unknown tripyrrane moieties with pentafluorobenzaldehyde has led to the formation of new generation heteroannulene (4.1.4.1) and mutant heteroannulene (1.1.1.1.1.1). Inclusion of local π‐aromatic sextets, namely the N‐methyl pyrrole rings through β,β‐linkages and α,β‐linkages, has led to the isolation of first ever heteroannulenes cross‐conjugated at four points and two points respectively within the macrocycles.     

Preparation of NiFe2O4 nanopowder via EDTA precursor and study of its properties

An ethylene diamine tetra acetic acid (EDTA) precursor-based chemical method is reported for preparing single-phase nickel ferrite (NiFe₂O₄) nanopowder. The synthesized powder was characterized by thermogravimetric analysis, differential scanning calorimetric analysis, X-ray diffraction, particle size analysis and scanning electron microscopy. DC electrical resistivity and magnetic property of the synthesized NiFe₂O₄ were measured by using a two-probe method and a vibrating sample magnetometer respectively. The DC resistivity behaviour of the NiFe₂O₄ nanopowder was correlated with the change of microstructure, during sintering. This EDTA precursor-based method is capable of producing nanostructured single-phase NiFe₂O₄ powder at a comparatively low calcination temperature and offers the potential of a simple and cost-effective route, including the preparation of other ferrite nanoparticles.     

Inducing efficiency in oligopolistic markets with increasing returns to scale

We consider a Cournot oligopoly market of firms possessing increasing returns to scale technologies (which may not be identical). It is shown that an external regulating agency can increase total social welfare without running a deficit by offering to subsidize one firm an amount which depends on the output level of that firm and the market price. The firms bid for this contract, the regulator collects the highest bid upfront and subsidizes the highest bidding firm. It is shown that there exists a subsidy schedule such that (i) the regulator breaks even, (ii) the subsidized firm obtains zero net profit and charges a price equal to its average cost, (iii) every other firm willingly exit the market and (iv) market price decreases, consumers are better off and total welfare improves.