Search results for "LIMIT"

2016

Abstract. Various geoscientific applications require a fast prediction of fracture permeability for an optimal workflow. Hence, the objective of the current study is to introduce and validate a practical method to characterize and approximate single flow in fractures under different stress conditions by using a core-flooding apparatus, in situ X-ray computed tomography (CT) scans and a finite-volume method solving the Navier–Stokes–Brinkman equations. The permeability of the fractured sandstone sample was measured stepwise during a loading–unloading cycle (0.7 to 22.1 MPa and back) to validate the numerical results. Simultaneously, the pressurized core sample was imaged with a medical X-ray…

Algorithmic differentiation for cloud schemes (IFS Cy43r3) using CoDiPack (v1.8.1)

2019

Abstract. Numerical models in atmospheric sciences not only need to approximate the flow equations on a suitable computational grid, they also need to include subgrid effects of many non-resolved physical processes. Among others, the formation and evolution of cloud particles is an example of such subgrid processes. Moreover, to date there is no universal mathematical description of a cloud, hence many cloud schemes have been proposed and these schemes typically contain several uncertain parameters. In this study, we propose the use of algorithmic differentiation (AD) as a method to identify parameters within the cloud scheme, to which the output of the cloud scheme is most sensitive. We il…

Algorithmic Differentiation for Cloud Schemes

2019

<p>Numerical models in atmospheric sciences do not only need to approximate the flow equations on a suitable computational grid, they also need to include subgrid effects of many non-resolved physical processes. Among others, the formation and evolution of cloud particles is an example of such subgrid processes. Moreover, to date there is no universal mathematical description of a cloud, hence many cloud schemes were proposed and these schemes typically contain several uncertain parameters. In this study, we propose the use of algorithmic differentiation (AD) as a method to identify parameters within the cloud scheme, to which the output of the cloud scheme is most sensitive.…

Resolvent estimates for the magnetic Schrödinger operator in dimensions ≥2

2020

It is well known that the resolvent of the free Schrödinger operator on weighted L2 spaces has norm decaying like λ−12 at energy λ . There are several works proving analogous high frequency estimates for magnetic Schrödinger operators, with large long or short range potentials, in dimensions n≥3 . We prove that the same estimates remain valid in all dimensions n≥2 . peerReviewed

Efecto de la masoterapia sobre la ictericia neonatal: revisión sistemática

2019

espanolObjetivo: Identificar, evaluar y sintetizar la mayor evidencia disponible sobre el efecto del masaje en la ictericia en neonatos a termino tratados o no con fototerapia. Metodo: Se desarrollo una revision siguiendo la declaracion PRISMA. Para ello se realizouna exhaustiva busqueda sistematica en las bases de datos PubMed, Cuiden, Scopus, Scielo y Cnki de los articulos publicados entre enero del 2009 y junio del 2018. Los estudios seleccionados fueron sometidos a una evaluacion de la calidad metodologica mediante la escala PEDro. Resultados: Un total de 10 trabajos cumplian los criterios inclusion y fueron incorporados a la revision. Estos presentaban una calidad metodologica moderada…

Long-term characterization of trihalomethane levels in drinking water

2010

Water chlorination leads to the formation of trihalomethanes (THM). In this case study, the levels of THM during the chlorination process of the drinking water in Valencia (Spain) were determined over a 12-year period. Different control areas and points were strategically sampled and samples were analyzed by gas chromatography. Temporal tendencies, as well as spatial and seasonal variations, were established. The individual distribution of THM was also evaluated. Factors such as distances from chlorination points and inter-month seasonal distribution, including ambient temperature effect, were assessed. The range of total THM concentrations measured in the water network goes from 4 to 184 µ…

First Life Cycle Impact Considerations of Two Wave Energy Converters

2018

The work presents two different revolutionary devices for the utilization of a new entry of renewable energy sources: sea wave. The first technology is based on linear generators, able to directly converts a linear motion into electrical output, limiting to minimum the chain of energy conversion. The other solution is based on a mechanical motion converter, coupled with alternators. The scope of this paper is to compare the two different systems designed by University of Palermo, through Life Cycle Assessment, in order to evaluate the global effects of the two systems to the environment.

Bifurcations of Regular Limit Periodic Sets

1998

In this chapter, (X λ ) will be a smooth or analytic (in Section 3) family of vector fields on a phase space S, with parameter λ ∈ P, as in Chapter 1. Periodic orbits and elliptic singular points which are limits of sequences of limit cycles are called regular limit periodic sets. The reason for this terminology is that for such a limit periodic set Γ one can define local return maps on transversal segments, which are as smooth as the family itself. The limit cycles near Γ will be given by a smooth equation and the theory of bifurcations of limit cycles from Γ will reduce to the theory of unfoldings of differentiable functions. In fact, we will just need the Preparation Theorem and not the …

Quantum Hopfield Model

2020

We find the free-energy in the thermodynamic limit of a one-dimensional XY model associated to a system of N qubits. The coupling among the &sigma

Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN

2019

We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.57 keV gives an effective neutrino mass square value of (−1.0−1.1+0.9) eV2. From this, we derive an upper limit of 1.1 eV (90% confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a …