A two-phase shallow debris flow model with energy balance

This paper proposes a thin layer depth-averaged two-phase model provided by a dissipative energy balance to describe avalanches of solid-fluid mixtures. This model is derived from a 3D two-phase model based on the equations proposed by Jackson [The Dynamics of Fluidized Particles. Cambridges Monographs on Mechanics (2000)] which takes into account the force of buoyancy and the forces of interaction between the solid and fluid phases. Jackson’s model is based on mass and momentum conservation within the two phases, i.e. two vector and two scalar equations. This system has five unknowns: the solid volume fraction, the solid and fluid pressures and the solid and fluid velocities, i.e. three scalars and two vectors. As a result, an additional equation is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson’s work. In particular, Pitman and Le [Philos. Trans. R. Soc. A 363 (2005) 799–819] replaced this closure simply by imposing an extra boundary condition. If the pressure is assumed to be hydrostatic, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here a closure equation to complete Jackson’s model, imposing incompressibility of the solid phase. We prove that the resulting whole 3D model is compatible with a dissipative energy balance. From this model, we deduce a 2D depth-averaged model and we also prove that the energy balance associated with this model is dissipative. Finally, we propose a numerical scheme to approximate the depth-averaged model. We present several numerical tests for the 1D case that are compared to the results of the model proposed by Pitman and Le

Dynamic Corrosion Test Using LiNO3 Containing Molten Salt for CSP Applications

Low melting point thermal energy storage (TES) materials have been proposed in the last years to reduce the storage cost in concentrating solar power (CSP) technology. One of the most interesting additive due to the enhancement in thermal properties is lithium nitrate. However, there is a lack of dynamic corrosion tests to simulate real operation conditions in CSP plants. In this work, we present a dynamic reactor set up where a mixture of 30 wt.% LiNO3 + 57 wt.% KNO3 + 13 wt.%. NaNO3 is moved through a mechanical stirrer obtaining a lineal speed of 0.30 m/s. A commercial carbon steel A516 was tested as container material at 390 °C during 1000 h. Fe2O3 and Fe3O4 were obtained as the main corrosion products by scanning electron microscopy (SEM) and x-ray diffraction (XRD) with a metallographic corrosion rate of 0.015 mm/year.The authors would like to thank the Catalan Government for the quality accreditation given to their research group (GREiA 2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia

Oligosacáridos utilizados para inhibir la mitosis de los astrocitos y de las células tumorales del sistema nervioso; y procedimiento de obtención de estos oligosacáridos

Traducción de Patente Europea E92923821 (fecha de solicitud, 13/11/1992).-- Prioridad: ES199111139102522.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).La invención se refiere a oligosacáridos y a preparaciones medicinales que contienen ingredientes orgánicos activos.Peer reviewe

Second Order Darboux Displacements

The potentials for a one dimensional Schroedinger equation that are displaced along the x axis under second order Darboux transformations, called 2-SUSY invariant, are characterized in terms of a differential-difference equation. The solutions of the Schroedinger equation with such potentials are given analytically for any value of the energy. The method is illustrated by a two-soliton potential. It is proven that a particular case of the periodic Lame-Ince potential is 2-SUSY invariant. Both Bloch solutions of the corresponding Schroedinger equation equation are found for any value of the energy. A simple analytic expression for a family of two-gap potentials is derived

The role of impulsivity in dropout from treatment for cigarette smoking

AbstractImpulsivity is a variable that has been associated with drug use. This study analyzes impulsivity from two different paradigms, one considering it as a trait and the other based on its behavioral correlates, such as disinhibition and impulsive decision-making in the treatment prognosis (maintain abstinence, relapse and dropout) of smokers after outpatient treatment. The participants in the study were 113 smokers who requested treatment for nicotine addiction. They were assigned to three groups according to whether or not they remained abstinent one month after beginning treatment; thus, group 1 was abstinent, group 2 had relapsed, and group 3 had dropped out of treatment. The participants filled out the Semi-structured Interview for Smokers, the Fargerström Test for Nicotine Dependence, the Temperament and Character Inventory-Revised (TCI-R) and the Delay Discounting Task (DDT). The Delay Discounting variable presents lower scores in the dropout group than in the relapse and abstinent groups, with the highest scores in the relapse group. Differences were also found on the Harm Avoidance (HA) variable, with lower scores in the dropout group compared to the relapse group. The importance of these results lies in the consideration of the smoker’s personality profile in order to prevent both dropout and relapse

Group theoretical approach to the intertwined Hamiltonians

We show that the finite difference B\"acklund formula for the Schr\"odinger Hamiltonians is a particular element of the transformation group on the set of Riccati equations considered by two of us in a previous paper. Then, we give a group theoretical explanation to the problem of Hamiltonians related by a first order differential operator. A generalization of the finite difference algorithm relating eigenfunctions of {\emph three} different Hamiltonians is found, and some illustrative examples of the theory are analyzed, finding new potentials for which one eigenfunction and its corresponding eigenvalue is exactly known

A Quantum Exactly Solvable Nonlinear Oscillator with quasi-Harmonic Behaviour

The quantum version of a non-linear oscillator, previouly analyzed at the classical level, is studied. This is a problem of quantization of a system with position-dependent mass of the form $m={(1+\lambda x^2)}^{-1}$ and with a \la-dependent nonpolynomial rational potential. This \la-dependent system can be considered as a deformation of the harmonic oscillator in the sense that for \la\to 0 all the characteristics of the linear oscillator are recovered. Firstly, the \la-dependent Schr\"odinger equation is exactly solved as a Sturm-Liouville problem and the \la-dependent eigenenergies and eigenfunctions are obtained for both \la>0 and \la<0. The \la-dependent wave functions appear as related with a family of orthogonal polynomials that can be considered as \la-deformations of the standard Hermite polynomials. In the second part, the \la-dependent Schr\"odinger equation is solved by using the Schr\"odinger factorization method, the theory of intertwined Hamiltonians and the property of shape invariance as an approach. Finally, the new family of orthogonal polynomials is studied. We prove the existence of a \la-dependent Rodrigues formula, a generating function and \la-dependent recursion relations between polynomials of different orders.Comment: 29 pages, 4 figure

The Phenomenon of Darboux Displacements

For a class of Schrodinger Hamiltonians the supersymmetry transformations can degenerate to simple coordinate displacements. We examine this phenomenon and show that it distinguishes the Weierstrass potentials including the one-soliton wells and periodic Lame functions. A supersymmetric sense of the addition formula for the Weierstrass functions is elucidated.Comment: 11 pages, latex, 2 eps figure

A One-Step, Versatile Synthesis of Dibenzo [n.2.2] Macrobicyclic Compounds via a Conformation-Directed Macrocyclization Reaction

A series of dibenzo [n.2.2] bicyclic compounds (n = 2–20) were prepared in one step and good yields starting from dimethyl anthracene-9,10-dicarboxylate. Reduction of the aromatic diester using lithium/naphthalene led to a bis-enolate that was cyclized with a variety of bis-electrophiles. The ease of the cyclization is probably due to the puckered conformation of the intermediate formed after the first alkylation step, in which the newly introduced chain that will become the bridge portion occupies a pseudoaxial position, positioning the leaving group close to the enolate nucleophile in the macrocyclization stepThis work was supported by the Ministerio de Economía y Competitividad of Spain (CTQ2011-22436) and Xunta de Galicia (PGIDIT10-PXIB209113PR, 10PXIB209155PR, and 2007/085)S