Effect of reaction conditions on the product distribution in the liquid-phase acid-catalyzed etherification of 2-naphthol with methanol

Summary Bi-doped TiO₂photocatalysts have been prepared by a sol-gel method. The samples were examined by the methods of XRD, HRTEM and XPS. The photocatalytic activity of the catalysts was evaluated through the photocatalytic oxidation of p-nitroaniline (NO₂C₆H₄NH₂) in air.     

Composites of poly[4-((p-tolylimino)methyl)phenyl acrylate] and the Ni-complex with aminated MWCNT: Thermal,electrical and magnetic investigation

Abstract

Its nickel complex and a polyacrylate with side chain the Schiff base obtained from the condensation reaction of 4-hydroxybenzaldehide and p-toluidine, have been synthesized. The three-component composites were prepared using the polyacrylate, poly[4-((p-tolylimino) methyl) phenyl acrylate], its Ni-complex, and aminated MWCNT at three different percent (2%, 8% and 15% by wt). For characterization, FT-IR, 1H-NMR, SEM-EDX, SEM images and VSM (vibrating sample magnetometer) were used. The specific magnetic susceptibility for the Ni-complex is calculated as 3.0?×?10^?8 m³/kg from the slope of VSM straight line and the Ni-complex shows paramagnetic property. Thermal stabilities of the composites decreased compared with the polymer and Ni-complex. The AC conductivities of the samples increased with increasing frequency and increasing temperature. Frequency exponent of the equation connecting the AC conductivity to angular frequency was calculated as between 1.06 and 0.86 at 298?K and between 0.97 and 0.71 at 320?K, for all samples. Log σ_ac vs 1000/T straight lines were generated above and below the T_g temperature and the activation energies were calculated from the slopes as the values between 0.097 and 0.331?eV below Tg and the values between 1.134 and 0.768?eV above T_g.     

Using support vector machines to learn the efficient set in multiple objective discrete optimization

We propose using support vector machines (SVMs) to learn the efficient set in multiple objective discrete optimization (MODO). We conjecture that a surface generated by SVM could provide a good approximation of the efficient set. As one way of testing this idea, we embed the SVM-approximated efficient set information into a Genetic Algorithm (GA). This is accomplished by using a SVM-based fitness function that guides the GA search. We implement our SVM-guided GA on the multiple objective knapsack and assignment problems. We observe that using SVM improves the performance of the GA compared to a benchmark distance based fitness function and may provide competitive results.     

Computing the nadir point for multiobjective discrete optimization problems

We investigate the problem of finding the nadir point for multiobjective discrete optimization problems (MODO). The nadir point is constructed from the worst objective values over the efficient set of a multiobjective optimization problem. We present a new algorithm to compute nadir values for MODO with \(p\) objective functions. The proposed algorithm is based on an exhaustive search of the \((p-2)\)-dimensional space for each component of the nadir point. We compare our algorithm with two earlier studies from the literature. We give numerical results for all algorithms on multiobjective knapsack, assignment and integer linear programming problems. Our algorithm is able to obtain the nadir point for relatively large problem instances with up to five-objectives.     

Statistical continuity in probabilistic normed spaces

In this study, we investigate the statistical continuity in a probabilistic normed space. In this context, the statistical continuity properties of the probabilistic norm, the vector addition and the scalar multiplication are examined.     

Reversible cation/anion extraction from K2La2Ti3O10: formation of new layered titanates, KLa2Ti3O9.5 and La2Ti3O9

A new soft-chemical transformation of layered perovskite oxides is described wherein K2O is sequentially extracted from the Ruddlesden-Popper (R-P) phase, K2La2Ti3O10 (I), yielding novel anion-deficient KLa2Ti3O(9.5) (II) and La2Ti3O9 (III). The transformation occurs in topochemical reactions of the R-P phase I with PPh4Br and PBu4Br (Ph = phenyl; Bu = n-butyl). The mechanism involves the elimination of KBr accompanied by decomposition of PR4+ (R = phenyl or n-butyl) that extracts oxygen from the titanate. Analysis of the organic products of decomposition reveals formation of Ph3PO, Ph3P, and Ph-Ph for R = phenyl, and Bu3PO, Bu3P along with butane, butene, and octane for R = butyl. The inorganic oxides II and III crystallize in tetragonal structures (II: P4/mmm, a = 3.8335(1) A, c = 14.334(1) A; III: I4/mmm, a = 3.8565(2) A, c = 24.645(2) A) that are related to the parent R-P phase. II is isotypic with the Dion-Jacobson phase, RbSr2Nb3O10, while III is a unique layered oxide consisting of charge-neutral La2Ti3O9 anion-deficient perovskite sheets stacked one over the other without interlayer cations. Interestingly, both II and III convert back to the parent R-P phase in a reaction with KNO3. While transformations of the R-P phases to other related layered/three-dimensional perovskite oxides in ion-exchange/metathesis/dehydration/reduction reactions are known, the simultaneous and reversible extraction of both cations and anions in the conversions K2La2Ti3O10 right harpoon over left harpoon KLa2Ti3O9.5 right harpoon over left harpoon La2Ti3O9 is reported here for the first time.     

Algorithm robust for the bicriteria discrete optimization problem

We apply Algorithm Robust to various problems in multiple objective discrete optimization. Algorithm Robust is a general procedure that is designed to solve bicriteria optimization problems. The algorithm performs a weight space search in which the weights are utilized in min-max type subproblems. In this paper, we experiment with Algorithm Robust on the bicriteria knapsack problem, the bicriteria assignment problem, and the bicriteria minimum cost network flow problem. We look at a heuristic variation that is based on controlling the weight space search and has an indirect control on the sample of efficient solutions generated. We then study another heuristic variation which generates samples of the efficient set with quality guarantees. We report results of computational experiments.