Search results for "Flow"
showing 10 items of 5185 documents
A full‐scale study of Darcy‐Weisbach friction factor for channels vegetated by riparian species
2021
In this article, an open channel flow resistance equation, deduced applying dimensional analysis and incomplete self-similarity condition for the flow velocity distribution, was tested using measurements carried out in a full-scale channel equipped with three types of riparian plants (Salix alba L., Salix caprea L. and Alnus glutinosa L.). In the experimental channel, having banks lined with boulders, the vegetation branches were anchored in a concrete bottom. For each species, the measurements were carried out with plants having different amounts of leaves, different plant density and plant area index. The relationship between the scale factor Γ of the velocity profile and the Froude numbe…
Microstructure, porosity and mineralogy around fractures in Olkiluoto bedrock
2012
3D distributions of minerals and porosities were determined for rock-core samples that included water-conducting fractures. The analysis of these samples was performed using conventional petrography methods, C-14-PMMA porosity analysis and X-ray tomography. It seems that the properties of rock around a water-conducting fracture depend on so many uncorrelated factors that no clear pattern emerged even for rock samples with a given type of fracture. We can conclude, however, that the present combination of methods can be used to infer novel structural information about alteration zones adjacent to fracture surfaces.
El problema del acortamiento de curvas asociado a una densidad
2016
A lo largo de la presente Tesis, se estudia el flujo por la curvatura media asociado a una densidad (FCMpsi) de una hipersuperficie, en una variedad riemanniana con densidad. Los principales resultados se obtienen para el caso particular en el que la dimensión de la variedad ambiente es dos y las subvariedades son curvas. A dicho problema, se le llamará problema del acortamiento de curvas asociado a una densidad (PACpsi). En el capítulo uno, se presentan los conceptos básicos para desarrollar y comprender el trabajo de la Tesis. Se da la definición del problema a abordar, se introducen las herramientas necesarias para su estudio y se calculan las fórmulas de variación de las cantidades geom…
Chemical composition of the essential oil from Pulicaria vulgaris var. graeca (Sch.-Bip.) Fiori (Asteraceae) growing wild in Sicily and its antimicro…
2015
In this study the chemical composition of the essential oil from aerial parts of Pulicaria vulgaris var. graeca (Sch.-Bip.) Fiori collected in Sicily was evaluated by GC and GCâMS. The main components of P. vulgaris var. graeca oil were hexadecanoic acid (21.7%), β-caryophyllene (14.3%) and geranyl propionate (8.2%). The comparison with other studied oils of genus Pulicaria is discussed. Antibacterial activity against several bacteria, including some ones infesting historical art craft, was also determined.
La laguna opaca. Gestión y gobernanza del agua en l’Albufera de València (España)
2019
International audience; The Albufera de Valencia is a complex anthropogenic waterscape, constructed by different social groups over centuries. Today water management in the protected wetland remains opaque, much like the water in the eutrophic lagoon. Four major organiza-tions manage this natural heritage, which remains torn between nature conservation and rice growing, in a jigsaw of overlap-ping jurisdictions and crisscrossed visions. Water management in this socioecological-system is complex and contested, and takes place within a changing scenario due to recent variations in the water quality and quantity budgets. This paper analyses this changing socio-ecological system based on interv…
Flow kinematic characteristics in the scour hole downstream of a grade-control structure
2010
Up-wind difference approximation and singularity formation for a slow erosion model
2020
We consider a model for a granular flow in the slow erosion limit introduced in [31]. We propose an up-wind numerical scheme for this problem and show that the approximate solutions generated by the scheme converge to the unique entropy solution. Numerical examples are also presented showing the reliability of the scheme. We study also the finite time singularity formation for the model with the singularity tracking method, and we characterize the singularities as shocks in the solution.
Estimer des flux de navetteurs avec un modèle gravitaire
2019
Dans ce poster, nous présentons le modèle gravitaire sous différents modèles en mettant en évidence les effets de distance et les occasions interposées. Le modèle généralisé de Newton est utilisé et donne des estimations relativement correctes des flux intercommunaux en région PACA.
Behind the curtain of international diversification: An agency theory perspective
2018
This paper dissects the antecedents of international diversification through the lens of the agency cost of free cash flow arguments. It explores whether the partial convergence of interests among managers, majority shareholders, and minority shareholders affects a firm's choice to diversify internationally. Using a sample panel of 60 Italian firms evaluated longitudinally from 2004 to 2014, the study tests whether a firm's international diversification is affected by its free cash flow (as the ultimate source of managerial discretion) and debt (as the main constraint to managerial discretion), especially in firm contexts that exacerbate agency problems. We find that the effects on internat…
Hydraulic Habitat Structure Impacts Risk of Trematode Infection
2022
Abstract— Variability in infection rates of trematodes Diplostomum pseudospathaceum in 0+ rainbow trout Oncorhynchus mykiss under different hydraulic regimes was studied in the experimental setup with regulated flow rates and environmental heterogeneity. The average infection rate in the conditions of the current was 1.5 times less than that in the stagnant water. An increase of the flow rate from 3.2 to 11.3 cm/s did not result in lower infection rates, while the interindividual variability in the infection rate (coefficient of variation) tended to increase along with changing the still-water conditions (20%) to the high flow rate environments (40%) within the experiment. A decrease in th…