Multiobjective Problems: Enhanced Necessary Conditions and New Constraint Qualifications through Convexificators

In this paper, we study necessary optimality conditions for local Pareto and weak Pareto solutions of multiobjective problems involving inequality and equality constraints in terms of convexificators. We develop the enhanced Karush–Kuhn–Tucker conditions and introduce the associated pseudonormality and quasinormality conditions. We also introduce several other new constraint qualifications which entirely depend on the feasible set. Then a connecting link between these constraint qualifications is presented. Moreover, we provide several examples that clarify the interrelations between the different results that we have established.     

A characterization of PSL(3,q) where q is an odd prime power

Order components of a finite group are introduced in Chen (J. Algebra 15 (1996) 184). We prove that PSL(3,q) can be uniquely determined by its order components where q is an odd prime power. A main consequence of our result is the validity of Thompson's conjecture for the groups under consideration.     

Identification of general linear relationships between activation energies and enthalpy changes for dissociation reactions at surfaces

The activation energy to reaction is a key quantity that controls catalytic activity. Having used ab inito calculations to determine an extensive and broad ranging set of activation energies and enthalpy changes for surface-catalyzed reactions, we show that linear relationships exist between dissociation activation energies and enthalpy changes. Known in the literature as empirical Br?nsted-Evans-Polanyi (BEP) relationships, we identify and discuss the physical origin of their presence in heterogeneous catalysis. The key implication is that merely from knowledge of adsorption energies the barriers to catalytic elementary reaction steps can be estimated.     

Simple ethers as models of sugar molecules in calculations of vertical excitation energies of DNA and RNA nucleosides

The ribose and deoxyribose molecules of RNA and DNA nucleosides are substituted with simple model compounds 1-methoxy-2-ethanol and 1-methoxypropane to mimic the effect of binding to sugars on the vertical excitation energies of purine and pyrimidine bases. The (R)-1-methoxy-2-ethanol, CH(3)OC*HCH(2)OH, for model ribose nucleosides and (R)-1-methoxypropane, CH(3)OC*HC(2)H(5), for model deoxyribose nucleosides have minimal structural characteristics of ribose and deoxyribose molecules when attached to nucleic acid purine and pyrimidine bases. The bases are attached to the C1 carbon atom designated by the asterisk. The vertical excitation energies of these model nucleosides are calculated with the time-dependent density functional theory method at the B3LYP level with 6-311++G(d,p) and aug-cc-pVDZ basis sets. The attachment of the ether molecules qualitatively and quantitatively modifies the excited state energy levels of the model nucleosides when compared to the free bases. These changes can affect the deexcitation mechanisms for photoexcited nucleosides.     

Syngas Production by Methane Reforming with Carbon Dioxide on Noble Metal Catalysts

A series of noble metal catalysts (Ru, Rh, Ir, Pt, and Pd) supported on alumina-stabilized magnesia (Spinel) were used to produce syngas by methane reforming with carbon dioxide. The synthesized catalysts were characterized using BET, TPR, TPO, TPH, and H2S chemisorption techniques. The activity results showed high activity and stability for the Ru and Rh catalysts. The TPO and TPH analyses indicated that the main reason for lower activity and stability of the Pd catalyst was the formation of the less reactive deposited carbon and sintering of the catalyst.     

Saturated nucleate boiling to binary and ternary mixtures on horizontal cylinder

In this investigation, a large number of experiments have been performed to determine saturated nucleate pool boiling heat transfer coefficients of MEA/water and DEA/water binary mixtures and that of water/MEA/DEA ternary mixtures. These heat transfer coefficients have been measured at atmospheric pressure and over a wide range of heat fluxes and solution concentrations. The heat flux has been varied in 14 different levels from 7 to about 230 kW/m² and amines concentration has been changed in 10 different levels from zero to 84 wt%. Results show that strong reduction of heat transfer coefficient occurs as a result of mass transfer interference in this phenomenon. Furthermore, in this study, all the correlations proposed during the last years for the prediction of nucleate boiling heat transfer coefficient of mixtures have been categorized in three groups. Some experimental results have been compared with the most accurate representatives of these three groups and the corresponding RMS errors have been calculated. Also, impacts of important existing parameters in these correlations like ideal heat transfer coefficient (h_id.) on the prediction have been discussed.