On-column N-dearylation of 2-azetidinones by silica-supported ceric ammonium nitrate

A modified traditional preparative chromatographic column can be used to achieve quantitative N-dearylation of N-(alkoxyphenyl), N-(alkoxynaphthyl), and N-(alkoxybenzyl)-2-azetidinones under mild conditions. Starting materials are charged on top of the column and the pure N-unsubstituted 2-azetidinones leave the column minutes later without need for other purifications. The yields are good-to-excellent and the reaction condition is mild, easy, efficient, and cheap.     

Synthesis, ab initio calculations, thermal, thermodynamic and antioxidant properties of some oxovanadium(IV) complexes containing N2O2 set of donor atoms

The formation constants of some oxovanadium(IV) binary complexes containing Schiff bases resulting from condensation of salicylaldehyde with aniline and with its derivatives were determined spectophotometrically. The synthesized compounds were characterized by analytical and different physico-chemical techniques like ¹H NMR, IR, elemental analysis, mass and UV-Vis spectral studies. The IR spectra affirm that coordination takes place through azomethine nitrogen and phenolate oxygen. Three of the VO(IV) Schiff base complexes i.e. bis(salicylideneaniline)oxovanadium(IV), [VO(L¹)₂], bis(salicylidene-4-methoxyaniline) oxovanadium (IV), [VO(L²)₂] and bis(salicylidene-4-cyanoaniline)oxovanadium(IV), [VO(L¹⁰)₂], were studied by thermogravimetry in order to evaluate their thermal stability and thermal decomposition pathways. The number of steps and, in particular, the starting temperature of decomposition of these complexes depends on the equatorial ligand. The complexes screened for antioxidant activity and the ab initio calculations were carried out to determine the structural and the geometrical properties of a typical vanadyl salicylideneaniline complex, [VO(L¹)₂].     

Integrated markdown pricing and aggregate production planning in a two echelon supply chain: A hybrid fuzzy multiple objective approach

Given high variability of demands for short life cycle products, a retailer has to decide about the products’ prices and order quantities from a manufacturer. In the meantime, the manufacturer has to determine an aggregate production plan involving for example, production, inventory and work force levels in a multi period, multi product environment. Due to imprecise and fuzzy nature of products’ parameters such as unit production and replenishment costs, a hybrid fuzzy multi-objective programming model including both quantative and qualitative constraints and objectives is proposed to determine the optimalprice markdown policy and aggregate production planning in a two echelon supply chain. The model aims to maximize the total profit of manufacturer, the total profit of retailer and improving service aspects of retailing simultaneously. After applying appropriate strategies to defuzzify the original model, the equivalent multi-objective crisp model is then solved by a fuzzy goal programming method. An illustrative example is also provided to show the applicability and usefulness of the proposed model and solution method.     

NaBrO3/NaHSO4 · H2O as a Versatile Reagent System for the Oxidation of Benzylic Alcohols and Aldehydes

The oxidation of benzylic alcohols and aldehydes by NaBrO₃ is efficiently promoted in the presence of NaHSO₄ · H₂O. All reactions were performed under mild and completely heterogeneous conditions in good to high yields.     

Adsorption of Thiophene on Aluminum Nitride Nanotubes

Abstract

Thiophene adsorption on pristine (6,0) aluminum nitride nanotubes was studied by using density functional theory calculations, by means of B3LYP and M06-L functionals. We present the nature of the thiophene interaction in different sites of the nanotube. Adsorption energies corresponding to adsorption of thiophene are calculated to be in the range ?18.90 to ?21.06 kJ mol^{? 1} Pablo, P. C., Liprandi, D. A. and Fígoli, N. S. 1996. Ind. Eng. Chem. Res., 34: 3713–3717. [Web of Science ®] , [Google Scholar]. It has been shown that the thiophene molecule has a weak physical adsorption on the pristine models due to weak Van der Waals interaction between the nanotubes and thiophene molecule. The charge transfer between thiophene and the AlNNT is minimal and the electronic properties of the nanotubes are not affected by the thiophene adsorption. Also, with change of tube type, more efficient binding could not be achieved. The results indicate that transition metal nanoclusters are more suitable catalyst with respect to nontransition metal nanotubes in the petroleum industry.     

A note on labelings of graphs

In this note we first study the structure of the incidence matrix of the complete graph on ν points and then we present a linear algebraic approach to labelling of finite simple graphs.     

Trading Signed Designs and Some New 4-(12, 5, 4) Designs

Variations of the trade-off method exist in the literature of design theory and have been utilized by some authors to produce some t-designs with or without repeated blocks. In this paper we explore a new version of this algorithmic method (i) to produce 20 nonisomorphic and rigid 4-(12,5,4) designs, (ii) to study the spectrum of support sizes of 4-(12,5,4) designs. Along these, we also present a new design invariant for testing isomorphism among designs and a new way of representing t-designs.     

A robust optimization approach to closed-loop supply chain network design under uncertainty

The concern about significant changes in the business environment (such as customer demands and transportation costs) has spurred an interest in designing scalable and robust supply chains. This paper proposes a robust optimization model for handling the inherent uncertainty of input data in a closed-loop supply chain network design problem. First, a deterministic mixed-integer linear programming model is developed for designing a closed-loop supply chain network. Then, the robust counterpart of the proposed mixed-integer linear programming model is presented by using the recent extensions in robust optimization theory. Finally, to assess the robustness of the solutions obtained by the novel robust optimization model, they are compared to those generated by the deterministic mixed-integer linear programming model in a number of realizations under different test problems.     

Dip coating fabrication process for micro-tubular SOFCs

This study investigates the dip coating fabrication process in detail. First the slurry formulation development is presented. This includes optimizing the concentration of slurry components. Controlling the coating thickness is then addressed. It is shown that a broad range of uniform thicknesses from a few microns up to a few hundreds of microns is achievable by adjusting the solid loading and/or the dip coating rate. This study reports that dip coating is a commercially reliable technique to fabricate micro-tubular solid oxide fuel cells not only because it is low cost but, more importantly, because it is fairly reproducible and highly controllable.