Massive spin-2 particle from a rank-2 tensor

Here we obtain all possible second-order theories for a rank-2 tensor which describe a massive spin-2 particle. We start with a general second-order Lagrangian with ten real parameters. The absence of lower-spin modes and the existence of two local field redefinitions leads us to only one free parameter. The solutions are split into three one-parameter classes according to the local symmetries of the massless limit. In the class which contains the usual massive Fierz-Pauli theory, the subset of spin-1 massless symmetries is maximal. In another class where the subset of spin-0 symmetries is maximal, the massless theory is invariant under Weyl transformations and the mass term does not need to fit into the form of the Fierz-Pauli mass term. In the remaining third class neither the spin-1 nor the spin-0 symmetry is maximal and we have a new family of spin-2 massive theories. © 2013 American Physical Society.

The reactive surface of Castor leaf [Ricinus communis L.] powder as a green adsorbent for the removal of heavy metals from natural river water

In this study, a green adsorbent was successfully applied to remove toxic metals from aqueous solutions. Dried minced castor leaves were fractionated into 63-μm particles to perform characterization and extraction experiments. Absorption bands in FTIR (Fourier Transform Infrared Spectroscopy) spectra at 1544, 1232 and 1350 cm-1 were assigned to nitrogen-containing groups. Elemental analysis showed high nitrogen and sulfur content: 5.76 and 1.93%, respectively. The adsorption kinetics for Cd(II) and Pb(II) followed a pseudo-second-order model, and no difference between the experimental and calculated Nf values (0.094 and 0.05 mmol g-1 for Cd(II) and Pb(II), respectively) was observed. The Ns values calculated using the modified Langmuir equation, 0.340 and 0.327 mmol g-1 for Cd(II) and Pb(II), respectively, were superior to the results obtained for several materials in the literature. The method proposed in this study was applied to pre-concentrate (45-fold enrichment factor) and used to measure Cd(II) and Pb(II) in freshwater samples from the Paraná River. The method was validated through a comparative analysis with a standard reference material (1643e). © 2013 Elsevier B.V. © 2013 Elsevier B.V. All rights reserved.

Synthesis and characterization of 3-[(thiourea)-propyl]-functionalized silica gel and its application in adsorption and catalysis

The objective of this research was the preparation of a silica gel functionalized successively with 3-chloropropyltrimethoxysilane (SG-PrCl) and thiourea (SG-Pr-THIO), and its application in adsorption and catalysis. The materials were characterized by 13C and 29Si NMR, FTIR, scanning electron micrographs (SEM), analysis of nitrogen and elemental analysis. Aiming at its application in adsorption, the [3-(thiourea)-propyl] silica gel (SG-Pr-THIO) was tested as an adsorbent for transition-metal ions using a batchwise process. The organofunctionalized surface showed the ability to adsorb the metal ions Cd(ii), Cu(ii), Ni(ii), Pb(ii) and Co(ii) from water, ethanol and acetone. The adsorption isotherms were fitted by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) models. The kinetics of adsorption of metals were performed using three models such as pseudo-first order, pseudo-second order and Elovich. The Langmuir and pseudo-first order models were the most appropriate to describe the adsorption and kinetic data, respectively. With the purpose of application in catalysis, the SG-Pr-THIO was reacted with a Mo(ii) organometallic complex, forming the new material SG-Pr-THIO-Mo. Only a few works in the literature have reported this type of reaction, and none dealt with thiourea and Mo(ii) complexes. The new Mo-silica gel organometallic material was tested as catalyst in the epoxidation of cyclooctene and styrene. © 2013 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Multiplicity and transverse momentum dependence of two- and four-particle correlations in pPb and PbPb collisions

Measurements of two- and four-particle angular correlations for charged particles emitted in pPb collisions are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 31nb-1, were collected during the 2013 LHC pPb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. The results are compared to 2.76 TeV semi-peripheral PbPb collision data, collected during the 2011 PbPb run, covering a similar range of particle multiplicities. The observed correlations are characterized by the near-side (|δφ|≈0) associated pair yields and the azimuthal anisotropy Fourier harmonics (vn). The second-order (v2) and third-order (v3) anisotropy harmonics are extracted using the two-particle azimuthal correlation technique. A four-particle correlation method is also applied to obtain the value of v2 and further explore the multi-particle nature of the correlations. Both associated pair yields and anisotropy harmonics are studied as a function of particle multiplicity and transverse momentum. The associated pair yields, the four-particle v2, and the v3 become apparent at about the same multiplicity. A remarkable similarity in the v3 signal as a function of multiplicity is observed between the pPb and PbPb systems. Predictions based on the color glass condensate and hydrodynamic models are compared to the experimental results. © 2013 CERN.

Zeros of a family of hypergeometric para-orthogonal polynomials on the unit circle

Para-orthogonal polynomials derived from orthogonal polynomials on the unit circle are known to have all their zeros on the unit circle. In this note we study the zeros of a family of hypergeometric para-orthogonal polynomials. As tools to study these polynomials, we obtain new results which can be considered as extensions of certain classical results associated with three term recurrence relations and differential equations satisfied by orthogonal polynomials on the real line. One of these results which might be considered as an extension of the classical Sturm comparison theorem, enables us to obtain monotonicity with respect to the parameters for the zeros of these para-orthogonal polynomials. Finally, a monotonicity of the zeros of Meixner-Pollaczek polynomials is proved. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Adsorção do corante reativo azul 19 em solução aquosa por lama vermelha tratada quimicamente com peró:xido de hidrogênio

Adsorption of Reactive Blue 19 dye onto activated red mud was investigated. Red mud was treated with hydrogen peroxide (LVQ) and heated at both 400 °C (LVQ400) and 500 °C (LVQ500). These samples were characterized by pH, specific surface area, point of zero charge and mineralogical composition. Adsorption was found to be significantly dependent on solution pH, with acidic conditions proving to be the most favorable. The adsorption followed pseudo-second-order kinetics. The Langmuir isotherm was the most appropriate to describe the phenomenon of dye removal using LVQ, LVQ400 and LVQ500, with maximum adsorption capacity of 384.62, 357.14 and 454.54 mg g-1, respectively.

Optimisation of High Hydrostatic Pressure Processing of Pêra Rio Orange Juice

The influence of high hydrostatic pressure (HHP) on Pêra Rio orange juice was investigated using response surface methodology. A central composite design was used to evaluate the effects of three processing conditions (independent variables), namely pressure (100-600 MPa), temperature (30-60 °C) and time (30-360 s), on the native microflora and pectin methylesterase (PME) activity of orange juice. Analysis of variance showed that second-order polynomial models fitted well with the experimental data for PME residual activity (R2 = 0.9586, p < 0.001) and aerobic microorganism count (R2 = 0.9879, p < 0.001). The optimum HHP processing conditions to produce orange juice with PME residual activity of less than 20 % and low microorganism count (<2 log cycles CFU/mL) were 550 to 600 MPa, 55 to 60 °C and 330 to 360 s. © 2013 Springer Science+Business Media New York.

Influência da seleção dos estágios incrementais sobre a intensidade de lactato mínimo: Estudo piloto

The purposes of this study were to assess the influence of stage selection from the incremental phase and the use of peak lactate after hyperlactatemia induction on the determination of the lactate minimum intensity (iLACmin). Twelve moderately active university students (23±5 years, 78.3±14.1 kg, 175.3±5.1 cm) performed a maximal incremental test to determine the respiratory compensation point (RCP) (initial intensity at 70 W and increments of 17.5 W every 2 minutes) and a lactate minimum test (induction with the Wingate test, the incremental test started at 30 W below RCP with increments of 10 W every 3 minutes) on a cycle ergometer. The iLACmin was determined using second order polynomial adjustment applying five exercise stage selection: 1) using all stages (iLACmin P); 2) using all stages below and two stages above iLACminP(iLACminA); 3) using two stages below and all stages above iLACminP(iLACminB); 4) using the largest and same possible number of stages below and above the iLACminP(iLACminI); 5) using all stages and peak lactate after hyperlactatemia induction (iLACminD). No differences were found between the iLACminP(138.2±30.2 W), iLACminA(139.1±29.1 W), iLACminB(135.3±14.2 W), iLACminI(138.6±20.5 W) and iLACmiD(136.7±28.5 W) protocols, and a high level of agreement between these intensities and iLACminPwas observed. Oxygen uptake, heart rate, rating of perceived exertion and lactate corresponding to these intensities was not different and was strongly correlated. However, the iLACminBpresented the lowest success rate (66.7%). In conclusion, stage selection did not influence the determination of iLACmin but modified the success rate. © Creative Commom.

The enzymatic recalcitrance of internodes of sugar cane hybrids with contrasting lignin contents

The recalcitrance in grasses varies according to cell type and maturation. The origin of the recalcitrance in different regions from sugar cane internodes with varied lignin contents was evaluated. The efficiency of enzymatic hydrolysis was correlated with the chemical, micromorphological and microspectrophotometric characteristics of the samples. The internodes of three sugar cane hybrids were dissected into four different fractions. The outermost fraction and the rind were the most recalcitrant regions, whereas the pith-rind interface and the pith were less recalcitrant. Cellulose conversion reached 86% after 72h of enzymatic digestion of the pith from the hybrid with the lowest lignin content. There was an inversely proportional correlation between the area occupied by vascular bundles and the efficiency of cellulose hydrolysis. High cellulose and low lignin or hemicellulose contents enhanced the efficiency of enzymatic hydrolysis of the polysaccharides. The critical evaluation of the results permitted to propose an empirical parameter for predicting cellulose conversion levels that accounts for the positive effect of high cellulose and low lignin plus hemicellulose and the detrimental effect of abundant vascular bundles. The cellulose conversion levels fit well to this calculated parameter, following a second order polynomial with an r2 value of 0.96. © 2013 Elsevier B.V.

Análise não suave e aplicações em otimização

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Semigrupos de operadores lineares limitados: soluções Mild e Weak

Pós-graduação em Matemática - IBILCE

Investigações sobre o impacto da modernização do GNSS no Posicionamento

Pós-graduação em Ciências Cartográficas - FCT

Eletroestimulador funcional de oito canais com malha de realimentação utilizando Controlador Digital

Pós-graduação em Engenharia Elétrica - FEIS

Um método previsor-corretor primal-dual de pontos interiores barreira logarítmica modificada, com estratégias de convergência global e de ajuste cúbico, para problemas de programação não-linear e não-convexa

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comportamento dinâmico não linear e controle de sistemas eletromecânicos em macro e micro escalas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)