Non-linear boundary element analysis of floor slabs reinforced with rectangular beams

In this work, a numerical model to perform non-linear analysis of building floor structures is proposed. The presented model is derived from the Kirchhoff-s plate bending formulation of the boundary element method (BENI) for zoned domains, in which the plate stiffness is modified by the presence of membrane effects. In this model, no approximation of the generalized forces along the interface is required and the compatibility and equilibrium conditions along interfaces are imposed at the integral equation level. In order to reduce the number of degrees of freedom, the Navier Bernoulli hypothesis is assumed to simplify the strain field for the thin sub-regions (rectangular beams). The non-linear formulation is obtained from the linear formulation by incorporating initial internal force fields, which are approximated by using the well-known cell sub-division. Then, the non-linear solution of algebraic equations is obtained by using the concept of the consistent tangent operator. The Von Mises criterion is adopted to govern the elasto-plastic material behaviour checked at points along the plate thickness and along the rectangular beam element axes. The numerical representations are accurately obtained by either computing analytically the element integrals or performing the numerical integration accurately using an appropriate sub-elementation scheme. (C) 2007 Elsevier Ltd. All rights reserved.

Reconstruction of deformed defects in field theory from deformed zero modes and applications

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cryopreservation of Dendrobium hybrid seeds and protocorms as affected by phloroglucinol and Supercool X1000

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Xylanase production by Bacillus circulans D1 using maltose as carbon source

Bacillus circulans D1 is a good producer of extracellular thermostable xylanase. Xylanase production in different carbon sources was evaluated and the enzyme synthesis was induced by various carbon sources. It was found that D-maltose is the best inducer of the enzyme synthesis ( 7.05 U/ mg dry biomass at 48 h), while D-glucose and D-arabinose lead to the production of basal levels of xylanase. The crude enzyme solution is free of cellulases, even when the microorganism was cultivated in a medium with D-cellobiose. When oat spelt xylan was supplemented with D-glucose, the repressive effect of this sugar on xylanase production was observed at 24 h, only when used at 5.0 g/ L, leading to a reduction of 60% on the enzyme production. on the other hand, when the xylan medium was supplemented with D- xylose ( 3.0 or 5.0 g/ L), this effect was more evident ( 80 and 90% of reduction on the enzyme production, respectively). Unlike that observed in the xylan medium, glucose repressed xylanase production in the maltose medium, leading to a reduction of 55% on the enzyme production at 24 h of cultivation. Xylose, at 1.0 g/ L, induced xylanase production on the maltose medium. on this medium, the repressive effect of xylose, at 3.0 or 5.0 g/ L, was less expressive when compared to its effect on the xylan medium.

A cooperative game theory analysis for transmission loss allocation

This paper presents an analysis and discussion, based on cooperative game theory, for the allocation of the cost of losses to generators and demands in transmission systems. We construct a cooperative game theory model in which the players are represented by equivalent bilateral exchanges and we search for a unique loss allocation solution, the Core. Other solution concepts, such as the Shapley Value, the Bilateral Shapley Value and the Kernel are also explored. Our main objective is to illustrate why is not possible to find an optimal solution for allocating the cost of losses to the users of a network. Results and relevant conclusions are presented for a 4-bus system and a 14-bus system. (c) 2007 Elsevier B.V. All rights reserved.

Concentração de flúor e solubilidade em esmalte de dentes decíduos permanentes jovens após aplicações tópicas de soluções fluoretadas.

The aim of this article was to compare, through the distillation method, the incorporated amount of fluoride and the reduction of solubility in the enamel of both deciduous and young permanent teeth, following topical application of a 2% neutral sodium fluoride solution, according to the Knutson's technique and a 1.23% of acidulated solution, according to the Wellock & Brudevold's technique. The greatest fluoride incorporation was observed in the deciduous teeth after the usage of the 2% neutral solution. The amount of calcium and phosphorus liberation by the acid solution was greatest in the control group, followed by the group of teeth treated in acidulated solution and, finally, by those treated in 2% sodium fluoride solution.

Production, characterization and properties of polysaccharide depolymerizing enzymes from a strain of Curvularia inaequalis

Xylanase, β-glucosidase, β-xylosidase, endoglucanase and polygalacturonase production from Curvularia inaequalis was carried out by means of solid-state and submerged fermentation using different carbon sources. β-Glucosidase, β-xylosidase, polygalacturonase and xylanase produced by the microorganisms were characterized. β-Glucosidase presented optimum activity at pH 5.5 whereas xylanase, polygalacturonase and β-xylosidase activities were optimal at pH 5.0. Maximal activity of β-glucosidase was determined at 60°C, β-xylosidase at 70°C, and polygalacturonase and xylanase at 55°C. These enzymes were stable at acidic to neutral pH and at 40-45°C. The crude enzyme solution was studied for the hydrolysis of agricultural residues.

Effect of 2% chlorhexidine on microtensile bond strength of composite to dentin

Purpose: To evaluate the effect of 2% chlorhexidine on the microtensile bond strength of composite resin to dentin treated with three dentin bonding systems. Materials and Methods: Flat dentinal surfaces were prepared in 24 extracted human third molars. Teeth were randomly divided into 8 distinct experimental groups according to the adhesive applied (Prime & Bond NT, Single Bond and Clearfil SE Bond), the application (yes/no) of chlorhexidine, and the time point at which it was applied (before or after acid etching the dentin). Composite resin blocks were built up over treated surfaces, and teeth were then stored in water at 37°C for 24 h. Samples were thermocycled, stored under the same conditions, and then vertically sectioned, thus obtaining specimens with 1.0 ± 0.1 mm2 cross-sectional area. Specimens were stressed in tension at 0.5 mm/min crosshead speed. Bond strength results were evaluated using a one-way ANOVA (p < 0.05). The modes of failures were verified using optical microscopy. Dentin disks were obtained from 3 additional teeth treated in the same manner for observation under SEM. The most representative samples of fractured specimens were also observed under SEM. Results: No statistically significant differences of bond strength values were found between any groups. Failures occurred mainly within the bond; exclusively adhesive fractures (adhesive-dentin) were not observed. Conclusion: The 2% chlorhexidine solution, applied before or after acid etching of the dentin, did not interfere with the microtensile bond strength of composite resin to the dentin treated with Prime & Bond NT, Single Bond, or Clearfil SE Bond bonding systems.

Mean-field model of interaction between bright vortex solitons in Bose-Einstein condensates

Using the explicit numerical solution of the axially symmetric Gross-Pitaevskii equation we study the dynamics of interaction among vortex solitons in a rotating matter-wave bright soliton train in a radially trapped and axially free Bose-Einstein condensate to understand certain features of the experiment by Strecker et al (2002 Nature 417 150). In a soliton train, solitons of opposite phase (phase δ = π) repel and stay apart without changing shape; solitons with δ = 0 attract, interact and coalesce, but eventually come out; solitons with a general δ usually repel but interact inelastically by exchanging matter. We study this and suggest future experiments with vortex solitons.

Thermal Behavior and Spectroscopic Study of Neutral and Cationic Mononuclear Cyclopalladated Compounds

The reactions of the precursor [Pd(N,C-dmba)(MeCN)2](NO 3) (1) (dmba = N,N-dimethylbenzylamine), with the proligands 3,5-dimethylpyrazole (Hdmpz), 2-quinolinethiol (qnSH) and 1,1′- bis(diphenylphosphine)ferrocene (dppf) afforded the compounds [Pd(N,C-dmba)(Hdmpz)(ONO2)]0.5CH2Cl2 (2), [Pd(N,C-dmba)(qnSH)(ONO2)] 0.5CH2Cl2 (3) and [Pd(N,C-dmba)(dppf)](NO3) (4), respectively. The mononuclear species 2,3 and 4 were characterized by elemental analysis, infrared spectroscopy, NMR and thermogravimetric analysis. The IR spectra show bands which are consistent with terminal monodentate nitrate group for 2-3 and ionic nitrate for 4. The 1H and 13C NMR data confirm that coordination of the organic ligands has occurred and the 31P{1H} NMR data for 4 clearly evidences the occurrence in solution of three cyclopalladated species with the dppf acting as a bridging ligand in two cases and as a chelate in one. The thermal behavior of compounds 1-4 suggests that complex 2 is the most stable. The X-ray diffractometry results show the formation of PdO from 1 and 2, Pd2OSO4 from 3, and of a mixture of PdO and Fe 2(PO4)3 from 4, as final decomposition products.

Concentração de sais da soluçtiao avaliada pela condutividade elétrica na zona radicular do crisântema sob irrigação por gotejamento

The effects of salt concentration levels in electrical conductivity (EC) were evaluated in chrysanthemum root, cultivated in substrate using two sampling methods, under greenhouse conditions. The experiment was carried out in Paranapanema, São Paulo using the experimental design in randomized blocks and four replications. The treatments consisted of eight sampling periods of substrate solutions in pots: 7, 14, 21, 28, 35, 42, 49 and 56 days after strike root and five salt concentration levels of applied saline solution: 1.42; 1.65; 1.89; 2.13 and 2.36 dS m -1 in the vegetative period and during the reproduction period of flower budding: 1.71; 1.97; 2.28; 2.57 and 2.85 dS m -1. The substrate solution EC monitoring was done using two methods: solution extractors and 1:2 water diluted solution. The use of solution extractors and 1:2 water diluted solution allowed substrate solution EC monitoring along the culture cycle; the amount of salt concentration applied in the substrate caused the substrate salinity increase; the method using solution extractors presented higher EC values in the substrate.

Analysis of numeric conditioning of Hessian matrix of Lagrangian via singular values

This paper presents an analyze of numeric conditioning of the Hessian matrix of Lagrangian of modified barrier function Lagrangian method (MBFL) and primal-dual logarithmic barrier method (PDLB), which are obtained in the process of solution of an optimal power flow problem (OPF). This analyze is done by a comparative study through the singular values decomposition (SVD) of those matrixes. In the MBLF method the inequality constraints are treated by the modified barrier and PDLB methods. The inequality constraints are transformed into equalities by introducing positive auxiliary variables and are perturbed by the barrier parameter. The first-order necessary conditions of the Lagrangian function are solved by Newton's method. The perturbation of the auxiliary variables results in an expansion of the feasible set of the original problem, allowing the limits of the inequality constraints to be reached. The electric systems IEEE 14, 162 and 300 buses were used in the comparative analysis. ©2007 IEEE.

In vitro antimicrobial efficiency of a mouthwash containing triclosan/gantrez and sodium bicarbonate

Several antiseptic substances have been used as adjuncts to routine mechanical procedures of oral hygiene, based on their antimicrobial effects. The objective of this study was to assess in vitro the antimicrobial efficiency of 2 mouthwash containing Triclosan/Gantrez and sodium bicarbonate in comparison to both positive and negative controls. Standard strain samples of Escherichia coli, Pseudomonas aeruginosa, Actinomyces viscosus and Bacillus subtilis were used. Samples of Streptococcus mutans and Gram-negative bacilli were collected from 20 volunteers (10 with a clinically healthy periodontium and 10 presenting biofilm-associated gingivitis). Evaluation of the antimicrobial activity was performed by determining the minimal inhibitory concentration (MIC). The results indicated that the test solution inhibited the growth of both Gram-negative and Gram-positive microorganisms from the volunteers' saliva as well as that of the standard strains at the MIC dilution of 1:20, whereas the MIC dilution of 0.12% chlorhexidine against the same bacteria was 1:80. Thus, even though the tested mouthrinse solution presented an in-vitro antimicrobial activity superior to that of a placebo, it was inferior to that of chlorhexidine.

Comparison of GEANT4 simulations with experimental data for thick al absorbers

Proton beams in medical applications deal with relatively thick targets like the human head or trunk. Therefore, relatively small differences in the total proton stopping power given, for example, by the different models provided by GEANT4 can lead to significant disagreements in the final proton energy spectra when integrated along lengthy proton trajectories. This work presents proton energy spectra obtained by GEANT4.8.2 simulations using ICRU49, Ziegler1985 and Ziegler2000 models for 19.68MeV protons passing through a number of Al absorbers with various thicknesses. The spectra were compared with the experimental data, with TRIM/SRIM2008 and MCNPX2.4.0 simulations, and with the Payne analytical solution for the transport equation in the Fokker-Plank approximation. It is shown that the MCNPX simulations reasonably reproduce well all experimental spectra. For the relatively thin targets all the methods give practically identical results but this is not the same for the thick absorbers. It should be noted that all the spectra were measured at the proton energies significantly above 2MeV, i.e., in the so-called Bethe-Bloch region. Therefore the observed disagreements in GEANT4 results, simulated with different models, are somewhat unexpected. Further studies are necessary for better understanding and definitive conclusions. © 2009 American Institute of Physics.

Lower-semicontinuity and optimization of convex functionals

The result that we treat in this article allows to the utilization of classic tools of convex analysis in the study of optimality conditions in the optimal control convex process for a Volterra-Stietjes linear integral equation in the Banach space G([a, b],X) of the regulated functions in [a, b], that is, the functions f : [a, 6] → X that have only descontinuity of first kind, in Dushnik (or interior) sense, and with an equality linear restriction. In this work we introduce a convex functional Lβf(x) of Nemytskii type, and we present conditions for its lower-semicontinuity. As consequence, Weierstrass Theorem garantees (under compacity conditions) the existence of solution to the problem min{Lβf(x)}. © 2009 Academic Publications.