Search results for "Vertical"
showing 10 items of 417 documents
Stiff landings are associated with increased ACL injury risk in young female basketball and floorball players
2016
Background: Few prospective studies have investigated the biomechanical risk factors of anterior cruciate ligament (ACL) injury. Purpose: To investigate the relationship between biomechanical characteristics of vertical drop jump (VDJ) performance and the risk of ACL injury in young female basketball and floorball players. Study Design: Cohort study; Level of evidence, 3. Methods: At baseline, a total of 171 female basketball and floorball players (age range, 12-21 years) participated in a VDJ test using 3-dimensional motion analysis. The following biomechanical variables were analyzed: (1) knee valgus angle at initial contact (IC), (2) peak knee abduction moment, (3) knee flexion angle at …
Thermally unstable throughflow of a power–law fluid in a vertical porous cylinder with arbitrary cross–section
2021
Abstract The present paper investigates how the cross–sectional shape of a vertical porous cylinder affects the onset of thermoconvective instability of the Rayleigh–Benard type. The fluid saturating the porous medium is assumed to be a non–Newtonian power–law fluid. A linear stability analysis of the vertical thorughflow is carried out. Three special shapes of the cylinder cross–section are analysed: square, circular and elliptical. The effect of changing the power–law index is investigated. The stability of a steady base state with vertical throughflow is analysed. The resulting stability problem is a differential eigenvalue problem that is solved numerically through the shooting method. …
Linear instability of the vertical throughflow in a horizontal porous layer saturated by a power-law fluid
2016
Abstract The effects of the vertical throughflow of a non-Newtonian power-law fluid on the onset of convective instability in a horizontal porous layer are investigated. The extended Darcy’s model of momentum diffusion is employed together with the Oberbeck–Boussinesq approximation. A stationary basic solution for the vertical throughflow is determined analytically. The basic velocity and temperature fields turn out to be independent of the non-Newtonian rheology. A linear stability analysis is carried out, leading to a fourth-order eigenvalue problem. A numerical solution of the eigenvalue problem is employed to obtain the neutral stability curves and the critical Rayleigh number for the o…
Volcaniclastic Deposition and migration of basin depocentres after the eruption of the Neapolitan Yellow Tuff: The Pozzuoli Bay (Naples, Italy)
2012
The Campi Flegrei is an active caldera located on the coastal zone of SW Italy (Fig. 1), close to the town of Naples Bay, that has been characterized by explosive activity and unrest throughout the Late Quaternary. This area represents a very active segment of the Eastern Tyrrhenian margin and may be regarded as an ideal laboratory to understand the mechanisms of caldera dynamics and the interplay between volcanism, tectonics and sedimentary processes along a continental back-arc margin. Recent research at Campi Flegrei has shown that a significant part of the offshore volcaniclastic products and structures, the late-stage geodynamic evolution of the inner caldera resurgence and the stratal…
Entry and exit in a vertically differentiated industry
2011
This paper presents a duopoly model of firm rivalry in a vertically differentiated industry when market dynamics is explicitly accounted for. It shows how the interplay between demand (degree of product differentiation, demand elasticity) and cost (fixed and quality costs) factors determine firms’ relative strength when quality is irreversible. The main strategic choices are product quality, price and the timing of entry and exit. Further, firms incur sunk quality costs at time of entry and operating fixed costs of maintaining quality. Although the low quality firm may outlast its rival in the declining phase, both firms wish to be the “quality leader”.
Del "dachgärten" al "green roofscape" (1970-2005). Aportación a la historia reciente del paisaje urbano
2007
El urbanismo suele considerar el paisaje urbano a pie de calle. Pero el umbral vertical de la urbe, el paisaje urbano que se descubre desde lo alto de una torre o sobrevolando la ciudad, apenas preocupa a nadie. Una de las alternativas paisajísticas al interminable panorama mineral conformado por las ciudades difusas del siglo XXI se puede encontrar en las nuevas cubiertas ajardinadas y en las nuevas perspectivas verdes que se ofrezcan desde los tejados. En este artículo cito unas cuantas terrazas ajardinadas (en alemán, dachgárten o terrassengárten) pero, sobre todo, me fijo en algunos proyectos de urbanismo verde que aspiran a hacer realidad el paisaje verde de altura (en inglés, green ro…
A Tomographical Characterization of L-convex Polyominoes
2005
Our main purpose is to characterize the class of L-convex polyominoes introduced in [3] by means of their horizontal and vertical projections. The achieved results allow an answer to one of the most relevant questions in tomography i.e. the uniqueness of discrete sets, with respect to their horizontal and vertical projections. In this paper, by giving a characterization of L-convex polyominoes, we investigate the connection between uniqueness property and unimodality of vectors of horizontal and vertical projections. In the last section we consider the continuum environment; we extend the definition of L-convex set, and we obtain some results analogous to those for the discrete case.
Quasilinear elliptic equations with singular quadratic growth terms
2011
In this paper, we deal with positive solutions for singular quasilinear problems whose model is [Formula: see text] where Ω is a bounded open set of ℝN, g ≥ 0 is a function in some Lebesgue space, and γ > 0. We prove both existence and nonexistence of solutions depending on the value of γ and on the size of g.
La transmissió lingüística intergeneracional a Castelló de la Plana i la Franja: La rellevància dels usos entre progenitors
2020
Fa 50 anys, a Conflicte lingüístic valencià, Rafael L. Ninyoles situava el trencament de la transmissió familiar del català com a resultat i manifestació externa de conflictes socials i de classes, especialment visibles enmig del procés de modernització econòmica i mobilitat social accelerada del País Valencià dels anys 60 del segle XX. En aquest article partim de dos estudis de cas quantitatius sobre la transmissió intergeneracional de les llengües a Castelló de la Plana i les comarques centrals de la Franja per a actualitzar el seu diagnòstic i matisar la visió d'aquest fenomen com a resultat de decisions dels progenitors imposades verticalment a la descendència. Hi proposem que els usos …
Rail track field testing using laser/air hybrid ultrasonic technique
2003
Nondestructive testing methods used for the testing of rail in tracks worldwide can be limited by discontinuity location or orientation within the rail. Vertical split head and rail base cracks are among those types of discontinuities that are difficult to detect, which in some cases may result in a reail failure in service. A noncontact and remote hybrid ultrasonic technique has been developed by combining laser generation with air coupled detection of ultrasonic signals in rails. The test apparatus mounts on a railroad pushcart and tests are performed in motion with all components kept above the running surface of the rail track. Tracks have been tested for vertical split head and rail ba…