Dissipation Scale Fluctuations and Chemical Reaction Rates in Turbulent Flows

Small separation between reactants, not exceeding $10^{-8}-10^{-7}cm$, is the necessary condition for various chemical reactions. It is shown that random advection and stretching by turbulence leads to formation of scalar-enriched sheets of {\it strongly fluctuating thickness} $\eta_{c}$. The molecular-level mixing is achieved by diffusion across these sheets (interfaces) separating the reactants. Since diffusion time scale is $\tau_{d}\propto \eta_{c}^{2}$, the knowledge of probability density $Q(\eta_{c},Re)$ is crucial for evaluation of chemical reaction rates. In this paper we derive the probability density $Q(\eta_{c},Re,Sc)$ and predict a transition in the reaction rate behavior from ${\cal R}\propto \sqrt{Re}$ ($Re\leq 10^{4}$) to the high-Re asymptotics ${\cal R}\propto Re^{0}$. The theory leads to an approximate universality of transitional Reynolds number $Re_{tr}\approx 10^{4}$. It is also shown that if chemical reaction involves short-lived reactants, very strong anomalous fluctuations of the length-scale $\eta_{c}$ may lead to non-negligibly small reaction rates

Scaling transformation and probability distributions for financial time series

The price of financial assets are, since Bachelier, considered to be described by a (discrete or continuous) time sequence of random variables, i.e a stochastic process. Sharp scaling exponents or unifractal behavior of such processes has been reported in several works. In this letter we investigate the question of scaling transformation of price processes by establishing a new connexion between non-linear group theoretical methods and multifractal methods developed in mathematical physics. Using two sets of financial chronological time series, we show that the scaling transformation is a non-linear group action on the moments of the price increments. Its linear part has a spectral decomposition that puts in evidence a multifractal behavior of the price increments.Comment: 10 pages, 4 figures, latex and ps file

The inactivated NDV-HXP-S COVID-19 vaccine induces a significantly higher ratio of neutralizing to non-neutralizing antibodies in humans as compared to mRNA vaccines

NDV-HXP-S is a recombinant Newcastle disease virus based-vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which expresses an optimized (HexaPro) spike protein on its surface. The vaccine can be produced in embryonated chicken eggs using the same process as that employed for the production of influenza virus vaccines. Here we performed a secondary analysis of the antibody responses after vaccination with inactivated NDV-HXP-S in a Phase I clinical study in Thailand. Please click Download on the upper right corner to see the full abstract

Flow boiling of refrigerant-oil mixtures in horizontal, plain and microfin tubes

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN021562 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Non-linear dynamics of mooring lines

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1997.Includes bibliographical references (p. 89).by Genevieve Tcheou.M.S

Formação do biofilme em canais radiculares medicados

Os microrganismos são os principais agentes etiológicos das alterações pulpares e periapicais. Uma vez que as células de defesa do hospedeiro não alcançam o interior dos canais radiculares, é necessário que os microrganismos sejam eliminados durante o tratamento endodôntico através do preparo químico e mecânico e medicação intracanal. Este estudo teve como objetivo testar a hipótese de que o Enterococcus faecalis é capaz de formar biofílme em canais radiculares que apresentam diferentes medicações intracanais. Para tanto, quarenta raízes de incisivos inferiores humanos com comprimento padronizado em 15 mm foram instrumentados e divididos em 6 grupos de acordo com a medicação intracanal testada (Clorexidina gel 2%, Ca(OH)2 + Clorexidina gel 2% (1:1), Ca{OH)2 + água destilada, sem medicação intracanal - grupo controle positivo, natrosol gel - grupo controle positivo e sem medicação intracanal e sem inoculação bacteriana - grupo controle negativo).Eppendorfs com as pontas cortadas foram inseridos em pequenos frascos de vidro contendo BHI caldo associado a neutralizadores da ação antimicrobiana específicos à cada medicação utilizada. Cada raiz, previamente instrumentada, foi posicionada no interior de cada conjunto frasco de vidro-eppendorf. Na interface dente-tampa, aplicou-se adesivo epóxi e cianoacrílato a fim de impedir uma contaminação bacteriana via interface no meio de cultura (Imura et. al., 1997).O aparato foi incubado a 37°C em câmara de C02. A turbidez do meio de cultura foi verificada diariamente. Os dias necessários para o crescimento bacteriano no BHI foram considerados como o tempo requerido para a contaminação das medicações intracanais testadas. A confirmação desta contaminação foi feita através do crescimento bacteriano em BHI agar, teste de catalase e Gram

An Inertial Algorithm for DC Programming

International audienc

Effet du champ cristallin sur la direction des moments magnétiques des ions de terres rares occupant des sites de très basse symétrie (C2-Cs)

We showed that it is possible to determine the magnetic moment direction in rareearth compounds of low site symetry (C2 or CS) using a crystal field calculation in the point charge model. This method was applied to the case of terbium oxide Tb2O3 as well as to different rareearth perovskites. The results are compared with experiment and shown to be in fairly good agreement.Dans les composés dont les sites de terres rares possèdent une basse symétrie (C2 ou Cs), il est possible de déterminer la direction des moments magnétiques à l'aide d'un calcul de champ cristallin en utilisant la méthode des charges ponctuelles. On a appliqué ce processus à l'oxyde de terbium Tb2O3 et aux différentes pérovskites de terre rare. Les résultats obtenus sont comparés à l'expérience et donnent un accord satisfaisant

PROPRIÉTÉS MAGNÉTIQUES DE Tb2O3 AUX BASSES TEMPÉRATURES

On explique que sur les sites de symétrie C3i les ions Tb3+ ne portent aucun moment magnétique alors que sur les sites de symétrie C2 ils sont ordonnés ; dans ce cas le fondamental cristallin est un doublet Non-Kramers faiblement décomposé. On détermine alors l'orientation des moments et on étudie, dans l'approximation du champ moléculaire, le moment effectif, la susceptibilité et l'aimantation de ce système.It is explained that Tb3+ ions on sites of C3i symmetry do not carry any magnetic moment while on sites of C2 symmetry they are ordered ; in this case the crystal field ground state is a slightly split Non-Kramers doublet. The orientation of the moments is then determined and the effective moment, susceptibility and magnetization of this system are analysed in the molecular field approximation

Scaling transformation and probability distributions for financial time series

The price of financial assets are, since Bachelier, considered to be described by a (discrete or continuous) time sequence of random variables, i.e a stochastic process. Sharp scaling exponents or unifractal behavior of such processes has been reported in several works. In this letter we investigate the question of scaling transformation of price processes by establishing a new connexion between non-linear group theoretical methods and multifractal methods developed in mathematical physics. Using two sets of financial chronological time series, we show that the scaling transformation is a non-linear group action on the moments of the price increments. Its linear part has a spectral decomposition that puts in evidence a multifractal behavior of the price increments.