hydraulic conductivity

Top PDF hydraulic conductivity:

Measurement of hydraulic conductivity under horizontal paths in granular soils

Measurement of hydraulic conductivity under horizontal paths in granular soils

In geotechnical structures, the permeability-dependent stability analysis is generally evaluated under vertical trajectories, because most permeameters are configured so that the water passes through the porous medium in this way. However, it is clear from the physical point of view that water can flow along different paths, including preferential ways that can include horizontal trajectories, parallel to the deposit of the stratum. The foregoing implies that both the vertical and horizontal component of the hydraulic conductivity or permeability coefficient must be estimated for a given stratum. The current research aims to explore possibilities for measuring the coefficient of permeability in horizontal trajectories, on granular soils, under a constant condition of relative density. For this purpose, a special chamber attached to a constant head permeameter was designed and constructed, which allows to measure the permeability in conditions of horizontal flow parallel to the soil layers. The proposed camera also admits the estimation of the permeability coefficient by combining stratifications of different granular soils, where the trajectories are not perfectly horizontal, but have diagonal paths. The results are compared with data obtained by conventional vertical flow permeameters, in order to check the difference in the measurements considering both situations in the samples. As a conclusion, it is important to report that there is evidently a difference in the permeability coefficients measured under different trajectories
Mostrar más

10 Lee mas

Influence of the scale range width on the determination of the hydraulic conductivity and effective porosity. The case of a porous aquifer in southern Italy

Influence of the scale range width on the determination of the hydraulic conductivity and effective porosity. The case of a porous aquifer in southern Italy

On the type and the most suitable mathematical representation of the examined parameters scaling laws it was already discussed in previous studies [33,35]. Specifically, Fallico et al. (2016) [34] proposed a not homogeneous power law model, to investigate the possible dependence upon more than a scale. These authors clarified also that a simple (homogeneous) power law model can be adopted for large values of the scale parameter, while for small values of this the inhomogeneous power law model should be used, in agreement with the concept of representative elementary volume [35]. Therefore, the purpose of this study consists in verifying whether the results obtained using scaling laws valid only for individual ranges of interest are more or less reliable than those obtained by the use of a single multiple scaling law, valid for the whole aquifer. For this purpose, the porous confined aquifer of Montalto Uffugo (Italy) test field was considered and several sets of hydraulic conductivity (k) and effective porosity (n e ) values, obtained by several different laboratory and field measurement methods, were used. Based on that, the experimental scaling laws of k = k (s) and n e = n e (s) were determined, where s is the scale, relating primarily to the field and the total or multiple experimental scales and comparisons between this last and the first were performed.
Mostrar más

18 Lee mas

Impact of a domestic wastewater treatment plant on groundwater pollution, north Jordan

Impact of a domestic wastewater treatment plant on groundwater pollution, north Jordan

Hydrogeological, statistical and graphical approaches have shown that Al Ramtha wastewater treatment plant (RWWTP) is the major source of groundwater contamina- tion in the Al Ramtha area, northern Jordan. High levels of nitrate were found in those wells located in close proximity of the treatment plant with more than 50% of the studied samples having concentration above the maximum per- missible limit of WHO drinking water quality standards (50 mg/L). Depth to groundwater, hydraulic conductivity, distance from the plant, and lineaments density dictate the aquifer’s vulnerability to contamination. Hydrochemical analysis has revealed that groundwater in the study area has a fresh-brackish, and hard to very hard composition. Groundwater chemistry has evolved from Ca-HCO 3 fresh
Mostrar más

14 Lee mas

TítuloAvaliaçâo in situ da condutividade hidráulica de solos de montanha: un caso de estudo na Serra da Estrela (Centro de Portugal)

TítuloAvaliaçâo in situ da condutividade hidráulica de solos de montanha: un caso de estudo na Serra da Estrela (Centro de Portugal)

Avaliação in situ da condutividade hidráulica de solos de montanha: un caso de estudo na Serra da Estrela Centro de Portugal In situ measurement of hydraulic conductivity of mountain soi[r]

22 Lee mas

Mediterranean tree coexistence: patterns, mechanisms and trends under a changing climate

Mediterranean tree coexistence: patterns, mechanisms and trends under a changing climate

We took two complementary approaches to compare physiological responses for temperate species which suffer distinct seasonal extremes during summer and winter. First, we conducted a detailed meta-analysis of several key plant functional variables - stomatal conductance (g s ), percent loss of hydraulic conductivity (PLC) and/or photoinhibition, indicated by low photochemical efficiency of photosystem II (F v /F m ) - in summer versus winter for three functional types of woody species (winter deciduous angiosperms, evergreen angiosperms and conifers) from sites with and without summer droughts across the temperate zone. Second, because the meta-analysis approach can be misleading due to pooling data for average patterns across species growing under disparate conditions and measured with varying techniques, we tested whether the findings of the global meta-analysis were supported in a case study of Mediterranean species in a drought-prone site in continental central Spain. Both sets of data allowed additional testing of the hypothesis that stomatal dynamics reflects the status of the hydraulic system (Sperry, 2000). Several empirical and theoretical studies have shown that stomatal closure tends to reflect loss of hydraulic function (Sperry, 2000; Meinzer et al., 2008; Johnson et al., 2011), both diurnally during the growing season and seasonally during ongoing water stress, though this has not been investigated to our knowledge across diverse species and communities.
Mostrar más

242 Lee mas

Anomalous dynamics of Darcy flow and diffusion through heterogeneous media

Anomalous dynamics of Darcy flow and diffusion through heterogeneous media

Flow in heterogeneous media is qualitative and quantitatively different from flow in homoge- neous media [Indelman and Rubin, 1996; Noetinger, B.Estebenet and Quintard, 2001; Keller, 2001]. The systematic investigation of the impact of spatial heterogeneity on the effective behavior of flow can be addressed by two interrelated strategies, which can be called coefficients ap- proach and dynamic approach. The coefficient approach quantifies flow in terms of effective coefficients such as effective hydraulic coefficients to insert in the classical flow equation. Ef- fective hydraulic conductivity is commonly requested by numerical models, widely used in groundwater management, as single effective parameter to consider in the flow equation and model flow in any d dimensional heterogeneous media. The dynamics approach deals with the up-scaling of the local scale equation in heterogeneous media. Stochastic average provides a systematic way to quantify the impact of heterogeneity on flow through heterogeneous me- dia and the derived effective equation is linked to a statistical description of heterogeneity. In this chapter we use stochastic methods to determine effective flow coefficient and to ob- tain an effective upscaled equation for flow in heterogeneous media characterized by spatially varying hydraulic conductivity. Within a stochastic approach, a spatially varying hydraulic conductivity in a heterogeneous medium is assumed to be one realization chosen from an ensemble of conductivity fields. Here we model variable hydraulic conductivity as random function and the mean behaviour for the hydraulic head, also modeled as a random function, is obtained considering ensemble average. Starting from a local problem we derive effective equation that is non local both in time and in space. Non locality implies that a description of flow in heterogeneous media in terms of effective coefficient could be not enough to catch
Mostrar más

178 Lee mas

Hydraulic modeling of fishways under variable hydrodynamic scenarios

Hydraulic modeling of fishways under variable hydrodynamic scenarios

Fishways are structures that aim to achieve the free movement of fish through transversal obstacles in rivers. Despite the wide research about their performance, their hydraulic study and characterization has been so far limited to uniform hydraulic conditions which are usually difficult to reach in natural scenarios, either because inaccurate building or simply because the studied situations during the design of the prototypes are never encountered. This study aims to model pool-type fishways with submerged notches and orifices under different regimes, and uniform and non-uniform performances. For this purpose, the classical formulation used in their design has been modified by studying a real-scale fishway under 29 different boundary conditions. The proposed new formulation together with a logical bottom- up iterative calculation is able to predict the observed water level distributions. This study demonstrates that orifices and notches can be considered independently when estimating the water level distribution and discharge through the fishway, and the need to modify the classical formulation. The modelling under non-uniform water level profiles will allow to enhance and adapt fishways to achieve a greater fish passage during longer time periods. Keywords: Pool-weir fishways; Water levels; Flow discharges; Hydraulic design; Non-uniform performance
Mostrar más

156 Lee mas

TítuloOn the cosimulation of multibody systems and hydraulic dynamics

TítuloOn the cosimulation of multibody systems and hydraulic dynamics

Similarly to the first case, for the double-actuator model, reference signals for the direc- tional valves of the hydraulic circuits are produced with a joystick. Figure 14 shows the resultant actuator lengths obtained with a monolithic simulation of 1 ms step-size. Although the system still seems fairly simple, the addition of the second hydraulic circuit as a new subsystem introduces an indirect coupling between the cylinders via the mechanical sys- tem, which from the co-simulation point of view, is significantly more challenging than the single-actuator case. The problem is solved again with the Jacobi-scheme co-simulation with different coupling strategies, as described before. To limit the number of considered variables, the same settings are used for both hydraulic subsystems.
Mostrar más

25 Lee mas

Multifunctional metal phosphonate frameworks for proton conductivity and photocatalysis

Multifunctional metal phosphonate frameworks for proton conductivity and photocatalysis

(x=15−16), were synthesized. Three-dimensional open frameworks resulted from the linkage of similar organo-inorganic layers, in the ac- plane, by central lanthanide ions, which yield trimeric units also found in other metal-HPAA compounds (Figure 1.5). Ln-HPAA networks enclose water-filled 1D channels and undergo remarkable crystalline- to-amorphous-to-crystalline transformations upon dehydration and rehydration cycles (Colodrero et al., 2012c). Both polymorphic forms showed proton conductivity at room temperature, with a gadolinium polymorph being highest proton conductor, while a europium derivative exhibited the best photo-luminescent properties, which are strongly dependent on dehydration-rehydration processes (Colodrero et al., 2012c).
Mostrar más

213 Lee mas

Preparación cristaloquímica y comportamiento eléctrico de electrolitos sólidos de estequiometría NASICON

Preparación cristaloquímica y comportamiento eléctrico de electrolitos sólidos de estequiometría NASICON

The ionic conductivity of LiGe2PO43 ∼10-5 S‚cm-1 at 300 °C may also be increased by partial substitution of Ge4+ by trivalent cations.23 The conductivity of Li1.5Ge1.5Al0.5PO43 compositi[r]

378 Lee mas

Formulación de la plataforma estratégica para la empresa  Hydraulic and Environmental Design S.A.S.

Formulación de la plataforma estratégica para la empresa Hydraulic and Environmental Design S.A.S.

La Empresa “Hydraulic and Environmental Design S.A.S.”, es una empresa de ingeniería fundada el 17 de abril del año 2009 en la Ciudad de Bogotá. Está dedicada a la ejecución de estudios y diseños de ingeniería sanitaria y ambiental para entidades públicas y privadas; desarrolla actualmente proyectos para sectores industriales, manejo de recurso hídrico, urbanismo, vial, edificaciones, Oil & gas y energía. La importancia de la formulación y ejecución de proyectos de inversión pública y privada en Colombia, ha permitido que empresas de este tipo, logren una ubicación con experiencia dentro del mercado. Sin embargo, para que sean competitivas y sigan creciendo, deben poseer un direccionamiento estratégico estructurado y claro, en donde la identidad y estrategias conocidas por toda la organización, permitan llegar a los objetivos deseados.
Mostrar más

136 Lee mas

Caracterización de la variabilidad espacial de propiedades del suelo a partir de la conductividad eléctrica aparente

Caracterización de la variabilidad espacial de propiedades del suelo a partir de la conductividad eléctrica aparente

OFFICER, S.J.; KRAVCHENKO, A.; BOLLERO, G.A.; SUDDUTH, K.A.; KITCHEN, N.R.; WIEBOLD, W.J.; PALM, H.L.; BULLOCK, D.G. (2004). Relationships between soil bulk electrical conductivity and the principal component analysis of topography and soil fertility values. Plant and Soil 258(1): 269-280.

7 Lee mas

Optimización de la geometría de la bomba hidráulica tipo Jet en el campo Coca mediante el software oilwell hydraulic para el mejoramiento de la producción

Optimización de la geometría de la bomba hidráulica tipo Jet en el campo Coca mediante el software oilwell hydraulic para el mejoramiento de la producción

La producción del campo Coca, declina su producción debido al cambio de la presión de fondo lo que produce un sobre dimensionamiento de la bomba jet como causa principal, presencia de escala por el alto contenido de agua que producen los pozos, taponamiento por corrosión de la tubería de inyección los mismos que son el causal del daño en el estado mecánico de bomba. Por este motivo se dará una recomendación para el cambio de geometría de la bomba jet mediante el programa Oil Well Hydraulic.

243 Lee mas

Enhanced conductivity and nonlinear voltage–current characteristics of nonstoichiometric BaTiO3 ceramics

Enhanced conductivity and nonlinear voltage–current characteristics of nonstoichiometric BaTiO3 ceramics

repressed, fired at 1250 °C for 6 hours, ground, pressed isostatically at 200 MPa, given a final firing at 1400 °C for 12h in air and then cooled slowly by switching off the furnace. We avoided the use of ball milling systems and media to mix samples since these are prone to the introduction of contaminants; all samples were, instead, hand-mixed and milled using an agate mortar and pestle. Using our normal procedures (10-15 min mixing, with acetone added periodically to form a paste), typical pellet densities after firing sol-gel derived samples were ~82%, Table I. Given the necessity to demonstrate that the results presented here were not, in some way, influenced by ceramic porosity, samples prepared by the solid state route used more extended hand-milling times (~1h) and in this way, pellets with densities as high as 98% were achieved, Table I. The electrical conductivity results, especially field-dependent conductivities, were found to be similar for samples of a given composition for pellets densities in the range ~82 to 98%, indicating that the electrical properties were essentially uninfluenced by ceramic porosity.
Mostrar más

51 Lee mas

Guest-molecule dynamics and conductivity effects in carbon-based molecular solids

Guest-molecule dynamics and conductivity effects in carbon-based molecular solids

(b) Plot of f max versus the space-charge relaxation frequency f σ (characteristic frequency of spatial charge fluctuations, see the text), in the same temperature interv[r]

243 Lee mas

Cuantificación de la erosión hídrica en el Perú y los costos ambientales asociados

Cuantificación de la erosión hídrica en el Perú y los costos ambientales asociados

El Capítulo 2 presenta el primer paper titulado: On a RUSLE-based methodology to estimate hydraulic erosion rates at country scale in developing countries, que plantea una metodología para estimar la erosión de suelos a escala nacional ante un contexto de escases de información básica como ocurre en los países en desarrollo. Tiene como producto mapas de la tasa de erosión de suelos en el Perú para los años 1990, 2000 y 2010 a una resolución de 5km.

41 Lee mas

Control de calidad de concreto lanzado usando fibra sintética en reemplazo de fibra metálica

Control de calidad de concreto lanzado usando fibra sintética en reemplazo de fibra metálica

Especificación estándar para la mezcla de agua utilizada en la producción de concreto de cemento hidráulico.  ASTM C143 – “Standard Test Method for Slump of Hydraulic-Cement Concrete”[r]

101 Lee mas

Hydraulic transients in hydropower plant . Impact on power system dynamic stability

Hydraulic transients in hydropower plant . Impact on power system dynamic stability

Abstract—Futaleufú hydropower plant has 4 Francis turbines rated 118 MW and it is connected to the power system by 2x330 kV lines. Studies carried out in the past did not predict the instable operation of Futaleufú after a 330 kV line fault, when some Futaleufú turbines are automatically disconnected as a consequence of the faulted line tripping. Load rejection caused by disconnected turbines generate large transients in the remaining turbines due to hydraulic coupling through the common conduits. Then, to improve related models and, therefore, to improve studies results of such a line fault it was necessary to make several tests in Futaleufú power plant. Finally, these models were used to conduct studies to design a new automatism, like the gate partial closing of the remaining turbines, to obtain a dynamically stable operation of Futaleufú after the disconnection by fault of a line of 330 kilovolts.
Mostrar más

1 Lee mas

solucionarioacidobase

solucionarioacidobase

19. (measuring) the pH / the strong acid solution will have a lower pH; conductivity (measurement) / the strong acid will be a better conductor; the strong acid will react more vigorously with metals/carbonates / the reaction with metals/carbonates;

14 Lee mas

HYDRAULIC MODELING OF MAGADALENA RIVER IN SOBEK

HYDRAULIC MODELING OF MAGADALENA RIVER IN SOBEK

Dicho convenio es el medio para desarrollar el proyecto de modelación hidráulica del Río Magdalena en un tramo de 800 km desde Puerto Salgar hasta la desembocadura en Barranquilla, en [r]

19 Lee mas

Show all 120 documents...