Search results for " Slope"
showing 10 items of 63 documents
Simple flume for flow measurement in sloping open channel
2007
First, this paper presents a new flume for measuring flow discharge in sloping channels, originally proposed by Samani and Magallanez for use in a horizontal channel. The flume is obtained by inserting two semicylinders in a rectangular cross section. Then, using dimensional analysis and the self-similarity theory, the stage-discharge relationship of the flume is theoretically deduced. For determining the two coefficients of the power stage-discharge equation, some experimental runs are carried out using flumes characterized by different values of the contraction ratio (ranging from 0.17 to 0.81) and of the flume slope (ranging from 0.5 to 3.5%). Finally, for a given range of the contractio…
Implications of terrain resolution on modeling rainfall-triggered landslides using a TIN- based model
2021
Abstract This study employs a distributed eco-hydrological-landslide model, the tRIBS-VEGGIE-Landslide, to evaluate the influence of terrain resolution on the hydro-geomorphological processes involved in slope stability analysis. The model implements a Triangulated Irregular Network (TIN) to describe the topography starting from a grid-DEM. Five grid-DEM resolutions of the case study basin, i.e., 10, 20, 30 and 70 m, are used to derive the corresponding TINs. The results show that using irregular meshes reduces the loss of accuracy with coarser resolutions in the derived slope distribution in comparison to slope distributions estimated from the original grid-based DEM. From a hydrological p…
Liquid-phase alkali-doping of individual carbon nanotube field-effect transistors observed in real-time
2011
The carbon nanotube (CNT) is known to be very sensitive to changes in its surrounding environment. Our study is on the effects of mild, liquid-phase alkali-doping on electronic transport in individual CNTs. We find clear and consistent reversal from p- to n-type behavior, with all seven investigated CNT field-effect transistors (FETs) retaining a similar ON/OFF ratio and subthreshold slope. We have also measured the realtime electronic response during liquid-phase doping, and demonstrate detection of alkali cations with a signal response that ranges over more than three orders of magnitude. The doping is fully reversible upon exposure to oxygen, and the doping cycle is repeatable. We also c…
Estimating flow resistance in steep slope rills
2021
Recent research recognized that the slope of 18% can be used to distinguish between the ‘gentle slope’ case and that of ‘steep slope’ for the detected differences in hydraulic variables (flow depth, velocity, Reynolds number, Froude number) and those representatives of sediment transport (flow transport capacity, actual sediment load). In this paper, using previous measurements carried out in mobile bed rills and flume experiments characterized by steep slopes (i.e., slope greater than or equal to 18%), a theoretical rill flow resistance equation to estimate the Darcy-Weisbach friction factor is tested. The main aim is to deduce a relationship between the velocity profile parameter Γ, the c…
Testing the Stage-Discharge Relationship in Sloping SMBF Flumes
2021
The Samani, Magallanez, Baiamonte, Ferro (SMBF) flume is a simple and inexpensive instrument for indirect discharge measurement that was originally proposed for use in a horizontal channel and then also applied in sloping channels. The contraction of the flow cross section, aimed at establishing a critical flow condition, is simply obtained by applying two half cylinders to the walls of a rectangular cross section. In this paper a theoretical approach previously proposed for a horizontal SMBF flume is first extended to a sloping SMBF flume and a new stage-discharge relationship is deduced. Then, this equation is experimentally tested using laboratory measurements from literature for differe…
Large Eddy Simulations of Rough Turbulent Channel Flows Bounded by Irregular Roughness: Advances Toward a Universal Roughness Correlation
2020
The downward shift of the mean velocity profile in the logarithmic region, known as roughness function, $$\Delta U^+$$ , is the major macroscopic effect of roughness in wall bounded flows. This speed decrease, which is strictly linked to the friction Reynolds number and the geometrical properties which define the roughness pattern such as roughness height, density, shape parameters, has been deeply investigated in the past decades. Among the geometrical parameters, the effective slope (ES) seems to be suitable to estimate the roughness function at fixed friction Reynolds number, Re $$_{\tau }$$ . In the present work, the effects of several geometrical parameters on the roughness function, i…
Dieta del delfín de Risso (Grampus griseus) en el Mediterráneo occidental
2006
The diet of Risso’s dolphin in the Mediterranean is described based on 15 animals stranded between 40°25’N 00°32’W and 37°35’N 00°45’E from April 1987 to January 2003. The prey were mainly oceanic cephalopods. Pelagic octopods, especially A. argo, were the most abundant (mean = 41.28%; SD±34.32). Species belonging to the families Ommastrephidae, Histioteuthidae and Onychoteuthidae were also frequent components of its diet. The bathymetric distribution of cephalopods shows that Risso’s dolphin preferentially feeds on the middle slope (600 to 800 m depth) in the Mediterranean.
Geo-hazards of the San Vito peninsula offshore (southwestern Tyrrhenian Sea)
2021
Geomorphological Tools for Mapping Natural Hazards.-- 12 pages, 7 figures, supplemental material https://doi.org/10.1080/17445647.2020.1866703.-- Software: The geomorphological main map and the Figures in the text were compiled using GLOBAL MAPPER, Surfer and Quantum-G GIS Software and redesigned to print with Adobe Illustrator
Physically-based and distributed approach to analyze rainfall-triggered landslides at watershed scale
2011
Abstract Landslides are a serious threat to life and property throughout the world. The causes of landslides are various since multiple dynamic processes are involved in driving slope failures. One of these causes is prolonged rainfall, which affects slope stability in different ways. Water infiltrating in a hillslope may cause a rise of the piezometric surface, which, in turn, involves an increase of the pore water pressure and a decrease of the soil shear resistance. For this reason, knowledge of spatio-temporal dynamics of soil water content, infiltration processes and groundwater dynamics, is of considerable importance in the understanding and prediction of landslides dynamics. In this …
The influence of slope angle on sediment, water and seed losses on badland landscapes
1997
Abstract By means of simulated rainfall the influence of the slope angle on the soil, water and seed erosion has been studied on badland surfaces. Slope angle has a clear positive effect controlling soil erodibility and erosion rates, but it does not have any influence on the volume of runoff after 40 minutes of rain at an intensity of 55 mm h−1. In contrast, slope angle has a clear influence on runoff initiation, with cracks and crusts as the main factors controlling the time to ponding and time to runoff. Both ponding and runoff initiation start earlier on pediments than on slopes, where more cracks exist. Steady-state infiltration rates and seed losses have an inverse relationships with …