Specific heat amplitude ratios for anisotropic Lifshitz critical behaviors

We determine the specific heat amplitude ratio near a $m$-axial Lifshitz point and show its universal character. Using a recent renormalization group picture along with new field-theoretical $\epsilon_{L}$-expansion techniques, we established this amplitude ratio at one-loop order. We estimate the numerical value of this amplitude ratio for $m=1$ and $d=3$. The result is in very good agreement with its experimental measurement on the magnetic material $MnP$. It is shown that in the limit $m \to 0$ it trivially reduces to the Ising-like amplitude ratio.Comment: 8 pages, RevTex, accepted as a Brief Report in Physical Review

Online Intelligent Controllers for an Enzyme Recovery Plant: Design Methodology and Performance

This paper focuses on the development of intelligent controllers for use in a process of enzyme recovery from pineapple rind. The proteolytic enzyme bromelain (EC 3.4.22.4) is precipitated with alcohol at low temperature in a fed-batch jacketed tank. Temperature control is crucial to avoid irreversible protein denaturation. Fuzzy or neural controllers offer a way of implementing solutions that cover dynamic and nonlinear processes. The design methodology and a comparative study on the performance of fuzzy-PI, neurofuzzy, and neural network intelligent controllers are presented. To tune the fuzzy PI Mamdani controller, various universes of discourse, rule bases, and membership function support sets were tested. A neurofuzzy inference system (ANFIS), based on Takagi-Sugeno rules, and a model predictive controller, based on neural modeling, were developed and tested as well. Using a Fieldbus network architecture, a coolant variable speed pump was driven by the controllers. The experimental results show the effectiveness of fuzzy controllers in comparison to the neural predictive control. The fuzzy PI controller exhibited a reduced error parameter (ITAE), lower power consumption, and better recovery of enzyme activity

The irreducible unitary representations of the extended Poincare group in (1+1) dimensions

We prove that the extended Poincare group in (1+1) dimensions is non-nilpotent solvable exponential, and therefore that it belongs to type I. We determine its first and second cohomology groups in order to work out a classification of the two-dimensional relativistic elementary systems. Moreover, all irreducible unitary representations of the extended Poincare group are constructed by the orbit method. The most physically interesting class of irreducible representations corresponds to the anomaly-free relativistic particle in (1+1) dimensions, which cannot be fully quantized. However, we show that the corresponding coadjoint orbit of the extended Poincare group determines a covariant maximal polynomial quantization by unbounded operators, which is enough to ensure that the associated quantum dynamical problem can be consistently solved, thus providing a physical interpretation for this particular class of representations.Comment: 12 pages, Revtex 4, letter paper; Revised version of paper published in J. Math. Phys. 45, 1156 (2004

Hidden new physics in meson decays

A model-independent analysis of a non-standard pseudoscalar contribution to leptonic meson decays ($\pi$,$K$,$D$,$D_s$ and $B$) is presented. As also seen from similar analyses in the literature, we find that two distinct regions in the parameter space arise, a region where the standard model contribution is predominant and a region where the new physics terms cancel precisely. So far, the latter has been regarded as a fine-tuning and for this reason it was neglected from the very beginning. This paper argues that this cancellation appears naturally in a class of models, most notably those that realize the Glashow-Weinberg-Paschos mechanism for avoiding flavor-changing neutral currents, in particular in the lepton sector. Thus, such a region that allows for larger Yukawa couplings ($10^{-4}\lesssim (G_\eta^{P}/G_F)U^{-1}m_l^{-1} \lesssim 10^{-3}$ MeV$^{-1}$) cannot be readily ruled out solely by the meson leptonic decays and is degenerated with the Standard Model prediction in these decays

A new picture of the Lifshitz critical behavior

New field theoretic renormalization group methods are developed to describe in a unified fashion the critical exponents of an m-fold Lifshitz point at the two-loop order in the anisotropic (m not equal to d) and isotropic (m=d close to 8) situations. The general theory is illustrated for the N-vector phi^4 model describing a d-dimensional system. A new regularization and renormalization procedure is presented for both types of Lifshitz behavior. The anisotropic cases are formulated with two independent renormalization group transformations. The description of the isotropic behavior requires only one type of renormalization group transformation. We point out the conceptual advantages implicit in this picture and show how this framework is related to other previous renormalization group treatments for the Lifshitz problem. The Feynman diagrams of arbitrary loop-order can be performed analytically provided these integrals are considered to be homogeneous functions of the external momenta scales. The anisotropic universality class (N,d,m) reduces easily to the Ising-like (N,d) when m=0. We show that the isotropic universality class (N,m) when m is close to 8 cannot be obtained from the anisotropic one in the limit d --> m near 8. The exponents for the uniaxial case d=3, N=m=1 are in good agreement with recent Monte Carlo simulations for the ANNNI model.Comment: 48 pages, no figures, two typos fixe

Durabilitatea unor mortare cu încorporare de microcapsule, care conțin materiale cu schimbare de fază

The construction is responsible for high consumptions of energy and raw materials. It becomes imperative to develop new sustainable constructive solutions. The mortars with incorporation of phase change materials (PCM) have the ability to regulate the temperature inside buildings, using only the energy supplied by the sun. The main focus of this study was the microstructure and durability of mortars with PCM incorporation. The binders studied were aerial lime, hydraulic lime, gypsum and cement. The proportions of PCM studied were 0% and 40% of the mass of the sand. It can be concluded that the incorporation of phase change material in mortars causes significant changes in their properties, in fresh and hardened state, such as microstructure, water absorption by capillarity and immersion, and degradation by freeze-thaw. Consequently, the addition of this material affects the durability and microstructure of the mortars developed.The authors acknowledge the Foundation for Science and Technology (FCT) for the financial support regarding PhD scholarship SFRH/BD/95611/2013.info:eu-repo/semantics/publishedVersio

Optically Based Charge Injection System for Ionization Detectors

An optically coupled charge injection system for ionization based radiation detectors which allows a test charge to be injected without the creation of ground loops has been developed. An ionization like signal from an external source is brought into the detector through an optical fiber and injected into the electrodes by means of a photodiode. As an application example, crosstalk measurements on a liquid Argon electromagnetic calorimeter readout electrodes were performed

Eficiência simbiótica e componentes de produção de caupi (Vigna unguiculata (L) Walp) em área irrigada do semi-árido baiano.

O objetivo deste trabalho foi o de avaliar a eficiência simbiótica e os componentes de produção do cultivo de feijão caupi inoculado com estirpes específicas em uma área irrigada do semi-árido baiano