Bulk dynamics for interfacial growth models

We study the influence of the bulk dynamics of a growing cluster of particles on the properties of its interface. First, we define a {\it general bulk growth model} by means of a continuum Master equation for the evolution of the bulk density field. This general model just considers arbitrary addition of particles (though it can be easily generalized to consider substraction) with no other physical restriction. The corresponding Langevin equation for this bulk density field is derived where the influence of the bulk dynamics is explicitly shown. Finally, when it is assumed a well-defined interface for the growing cluster, the Langevin equation for the height field of this interface for some particular bulk dynamics is written. In particular, we obtain the celebrated Kardar-Parisi-Zhang (KPZ) equation. A Monte Carlo simulation illustrates the theoretical results.Comment: 6 pages, 2 figure

EFEITO DA TEMPERATURA NA SÍNTESE DE FERTILIZANTES DO TIPO TERMOPOTÁSSIO

No Brasil, o uso de fertilizantes intensificou-se com o propósito de aumentar a sua produtividade agrícola. Uma consequência disso é o aumento nas importações de fertilizantes, uma vez que, a produção interna tornou-se insatisfatória. Baseado neste cenário é importante o desenvolvimento de fontes alternativas de sais de potássio para aplicação na agricultura como fertilizantes potássicos. Neste trabalho, propõe-se o desenvolvimento de fertilizantes termopotássicos, tomando-se como ponto de partida o verdete de Cedro do Abaeté. A rocha foi caracterizada pelas técnicas de espectroscopia vibracional na região do infravermelho (IV), fluorescência de raios X (FRX) e difração de raios X (DRX). A existência da glauconita foi confirmada por DRX, pela análise de picos característicos em 10; 4,5; 2,4 e 1,5 Å, e por IV pelas bandas em 3520, 3440, 1020 e 630 cm-1. O teor de K2O (7%) na rocha foi determinado por FRX. Esse teor advém dos minerais de potássio que constituem a rocha, sendo o principal deles a glauconita. Dos 7% em massa de K2O, que constituem o verdete, somente 0,4%, do K total, se encontram na forma solúvel. Visando a aumentar esse percentual calcinou-se a rocha a 800, 1.000 e 1.200?C e a solubilidade do nutriente passou a 2,5; 0,5 e 0,06%, do K total, respectivamente

Centralized Inverted Decoupling Control

This paper presents a new methodology of multivariable centralized control based on the structure of inverted decoupling. The method is presented for general n×n processes, obtaining very simple general expressions for the controller elements with a complexity independent of the system size. The possible configurations and realizability conditions are stated. Then, the specification of performance requirements is carried out from simple open loop transfer functions for three common cases. As a particular case, it is shown that the resulting controller elements have PI structure or filtered derivative action plus a time delay when the process elements are given by first order plus time delay systems. Comparisons with other works demonstrate the effectiveness of this methodology through the use of several simulation examples and an experimental lab process

Characterization of the Lago Mare sedimentation (latest Messinian) and the transgression of the beginning of the Pliocene in the Malaga basin (Betic Cordillera)

A stratigraphic unit deposited close to the Messinian-Pliocene boundary is newly discovered in the Malaga basin. This unit mainly consist of alluvial and lagoonal deposits. Paleontological and paleomagnetic data from these deposits and from the overlying sediments indicate that the former were formed in the latest Miocene, thus can be correlated with the so-called Lago Mare deposits. The latest Messinian and lower Pliocene deposits are separated by an erosive surface (latest-Messinian discontinuity) that is related to a relative sea-level fall previous to the earliest Pliocene general floodin

Observation of two new Ξb−\Xi_b^- baryon resonances

Two structures are observed close to the kinematic threshold in the $\Xi_b^0 \pi^-$ mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb$^{-1}$ recorded by the LHCb experiment. In the quark model, two baryonic resonances with quark content $bds$ are expected in this mass region: the spin-parity $J^P = \frac{1}{2}^+$ and $J^P=\frac{3}{2}^+$ states, denoted $\Xi_b^{\prime -}$ and $\Xi_b^{*-}$. Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be $m(\Xi_b^{\prime -}) - m(\Xi_b^0) - m(\pi^{-}) = 3.653 \pm 0.018 \pm 0.006$ MeV$/c^2$, $m(\Xi_b^{*-}) - m(\Xi_b^0) - m(\pi^{-}) = 23.96 \pm 0.12 \pm 0.06$ MeV$/c^2$, $\Gamma(\Xi_b^{*-}) = 1.65 \pm 0.31 \pm 0.10$ MeV, where the first and second uncertainties are statistical and systematic, respectively. The width of the lighter state is consistent with zero, and we place an upper limit of $\Gamma(\Xi_b^{\prime -}) < 0.08$ MeV at 95% confidence level. Relative production rates of these states are also reported.Comment: 17 pages, 2 figure

Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays

Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201