Predictive modeling in a steelmaking process using optimized relevance vector regression and support vector regression

Annals of Operations Research - The existence of contaminants in metal alloys products is the main problem affecting the product quality, which is an important requirement for competitiveness in...     

A multilinear Lindenstrauss theorem

We show that the set of N-linear mappings on a product of N Banach spaces such that all their Arens extensions attain their norms (at the same element) is norm dense in the space of all bounded N-linear mappings.     

Assessment of the correlation between mechanical testing and positron annihilation outcomes for RPV model alloys

The correlation between recent PAS results and the outcomes from mechanical testing of RPV model alloys are presented, here significant changes due to different chemical composition and different irradiation levels are observed. The influence of alloying elements to the microstructure degradation process following irradiation was identified by analysis of the mean-lifetime parameter, since an interesting interdependency of this parameter with hardness was observed.     

James type results for polynomials and symmetric multilinear forms

We prove versions of James' weak compactness theorem for polynomials and symmetric multilinear forms of finite type. We also show that a Banach spaceX is reflexive if and only if it admits and equivalent norm such that there existsx ₀≠0 inX and a weak-^*-open subsetA of the dual space, satisfying thatx ^*⊗x ₀ attains its numerical radius. for eachx ^* inA. The first and third author were supported in part by D.G.E.S., project no. BFM 2000-1467. The second author was partially supported by Junta de Andalucía Grant FQM0199.     

Six polycyclic pyrimidoazepine derivatives: syntheses,molecular structures and supramolecular assembly

A versatile synthetic method has been developed for the formation of variously substituted polycyclic pyrimidoazepine derivatives, formed by nucleophilic substitution reactions on the corresponding chloro‐substituted compounds; the reactions can be promoted either by conventional heating in basic solutions or by microwave heating in solvent‐free systems. Thus, (6RS)‐6,11‐dimethyl‐3,5,6,11‐tetrahydro‐4H‐benzo[b]pyrimido[5,4‐f]azepin‐4‐one, C₁₄H₁₅N₃O, (I), was isolated from a solution containing (6RS)‐4‐chloro‐8‐hydroxy‐6,11‐dimethyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepine and benzene‐1,2‐diamine; (6RS)‐4‐butoxy‐6,11‐dimethyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepin‐8‐ol, C₁₈H₂₃N₃O₂, (II), was formed by reaction of the corresponding 6‐chloro compound with butanol, and (RS)‐4‐dimethylamino‐6,11‐dimethyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepin‐8‐ol, C₁₆H₂₀N₄O, (III), was formed by reaction of the chloro analogue with alkaline dimethylformamide. (6RS)‐N‐Benzyl‐8‐methoxy‐6,11‐dimethyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepin‐4‐amine, C₂₂H₂₄N₄O, (IV), (6RS)‐N‐benzyl‐6‐methyl‐1,2,6,7‐tetrahydropyrimido[5′,4′:6,7]azepino[3,2,1‐hi]indol‐8‐amine, C₂₂H₂₂N₄, (V), and (7RS)‐N‐benzyl‐7‐methyl‐2,3,7,8‐tetrahydro‐1H‐pyrimido[5′,4′:6,7]azepino[3,2,1‐ij]quinolin‐9‐amine, C₂₃H₂₄N₄, (VI), were all formed by reaction of the corresponding chloro compounds with benzylamine under microwave irradiation. In each of compounds (I)–(IV) and (VI), the azepine ring adopts a conformation close to the boat form, with the C‐methyl group in a quasi‐equatorial site, whereas the corresponding ring in (V) adopts a conformation intermediate between the twist‐boat and twist‐chair forms, with the C‐methyl group in a quasi‐axial site. No two of the structures of (I)–(VI) exhibit the same range of intermolecular hydrogen bonds: different types of sheet are formed in each of (I), (II), (V) and (VI), and different types of chain in each of (III) and (IV).     

Crystal structures of five new substituted tetrahydro‐1‐benzazepines with potential antiparasitic activity

Tetrahydro‐1‐benzazepines have been described as potential antiparasitic drugs for the treatment of chagas disease and leishmaniasis, two of the most important so‐called `forgotten tropical diseases' affecting South and Central America, caused by Trypanosoma cruzi and Leishmania chagasi parasites, respectively. Continuing our extensive work describing the structural characteristics of some related compounds with interesting biological properties, the crystallographic features of three epoxy‐1‐benzazepines, namely (2SR,4RS)‐6,8‐dimethyl‐2‐(naphthalen‐1‐yl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, (1), (2SR,4RS)‐6,9‐dimethyl‐2‐(naphthalen‐1‐yl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, (2), and (2SR,4RS)‐8,9‐dimethyl‐2‐(naphthalen‐1‐yl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, (3), all C₂₂H₂₁NO, and two 1‐benzazepin‐4‐ols, namely 7‐fluoro‐cis‐2‐[(E)‐styryl]‐2,3,4,5‐tetrahydro‐1H‐1‐benzazepin‐4‐ol, C₁₈H₁₈FNO, (4), and 7‐fluoro‐cis‐2‐[(E)‐pent‐1‐enyl]‐2,3,4,5‐tetrahydro‐1H‐1‐benzazepin‐4‐ol, C₁₅H₂₀FNO, (5), are described. Some peculiarities in the crystallization behaviour were found, involving significant variations in the crystalline structures as a result of modest changes in the peripheral substituents in (1)–(3) and the occurrence of discrete disorder due to the molecular overlay of enantiomers with more than one conformation in (5). In particular, an interesting phase change on cooling was observed for compound (5), accompanied by an approximate fourfold increase of the unit‐cell volume and a change of the Z′ value from 1 to 4. This transition is a consequence of the partial ordering of the pentenyl chains in half of the molecules breaking half of the symmetry axes observed in the room‐temperature structure of (5). The structural assembly in all the title compounds is characterized by not only (N,O)—H…(O,N) hydrogen bonds, but also by unconventional C—H…O contacts, resulting in a wide diversity of packing.     

Sub-barrier fusion of 6He with 206Pb

Cross-sections for the production of ²¹⁰Po nuclei in ⁶He + ²⁰⁶Pb collisions over the incident energy range 14-18MeV were measured by means of the activation technique and a radiochemical analysis. The elastic scattering at 18.0MeV was also measured providing a precise value for the ²¹⁰Po production cross-section at this energy. The results are at variance with the earlier experimental data and rather in accord with the predictions of a density-dependent barrier penetration model for the fusion process. A proper treatment of beam energy distribution for the evaluation of the activation data is discussed.     

On a problem of Namioka on norm-attaining functionals

Isaac Namioka conjectured that every nonreflexive Banach space can be renormed is such a way that, in the new norm, the set of norm attaining functionals has an empty interior in the norm topology. We prove the rightness of this conjecture for spaces containing an isomorphic copy of ℓ₁. As a consequence, we prove also that the same result holds for a wide class of Banach spaces containing, for example, the weakly compactly generated ones.     

Aspects of xylitol formation in sugarcane bagasse hydrolysate by Candida guillie rmondii in the presence of tetracycline

The biocon version of xylose intoxylitol using pH values of 4.0, 5.5 and 7.0 and tetracycline concentrations of 20 and 40 mg/L was carried out to verify the influence of these parameters on Candida guilliermondii metabolism for xylitol production. Experiments were performed with sugarcane bagasse hemicellulosi chydrolysate (48.5 g/L of xylose) in 125-mL Erlenmeyer flasks, at 30°C, 200 rpm, during 88 h. The results demostrated that the bioconversion of xylose into xylitol was significantly influenced by the pH. On the other hand, in media containing 20 or 40 mg/L of tetracycline, this bioconversion was not significantly affected. The best results of xylitol production were obtained in hemicellulosic hydrolysate without tetracycline, at pH 7.0 In these conditions, the maxim um specific growth rate was 0.014/h and the yield factor of xylitol and volumetric productivity were 0.85g/g and 0.70g/L/h respectively. Xylitol and cell growth occureed simultaneously.