Search results for "ER retention"
showing 10 items of 90 documents
Assessing the influence of different biochar fractions on soil structure and soil water retention: laboratory investigation on a Sicilian soil
2012
Testing the shape-similarity hypothesis between particle-size distribution and water retention for Sicilian soils
2012
Application of the Arya and Paris (AP) model to estimate the soil water retention curve requires a detailed description of the particlesize distribution (PSD) but limited experimental PSD data are generally determined by the conventional sieve-hydrometer (SH) method. Detailed PSDs can be obtained by fitting a continuous model to SH data or performing measurements by the laser diffraction (LD) method. The AP model was applied to 40 Sicilian soils for which the PSD was measured by both the SH and LD methods. The scale factor was set equal to 1.38 (procedure AP1) or estimated by a logistical model with parameters gathered from literature (procedure AP2). For both SH and LD data, procedure AP2 …
Yielding of a quartz sand from saturated to dry state
2020
The paper presents the results of an experimental work where we analyse the behaviour of an unsaturated quartz sand in a wide range of degree of saturation (from saturated to dry state). The possibility of anticipating the hydro-mechanical behaviour of the soils when they approach the dry state is fundamental in many areas. An extensive experimental program, including controlled-suction and constant water content oedometric tests, was carried out to deeply analyse the water retention behaviour and the relationship between the yield stress and suction (Loading-Collapse curve). All elasto-plastic models provide a monotonically increase of the yield stress with suction. This assumption implies…
Suction controlled drying and wetting cycle effects on the volumetric behaviour of a lime-treated high plasticity clay
2016
The paper presents some experimental results collected on samples recovered from an experimental embankment obtained by compacting a lime-treated clay. Samples were collected soon after the in situ compaction and they were cured in controlled environmental conditions for at least 18 months. Mercury intrusion porosimetry tests (MIP) were carried out on freeze-dried specimens to characterize the microstructure of the material. In order to assess the durability of the improved material, laboratory tests focused on the effects of cyclic variations of the degree of saturation on the water retention properties and the volumetric behaviour of the stabilized clay. Collected results show that the li…
Hydro-mechanical behaviour of a sandy silt from a river embankment
2020
The paper presents the results of an experimental campaign aimed at characterizing the hydro-mechanical behaviour of a sandy silt from a river embankment. Due to continuous river level fluctuations and changing climatic and environmental conditions, flood embankment materials experience frequent variations in degree of saturation and suction values. Such variations strongly impact the earthwork performance both in terms of seepage and stability conditions. For these reasons, a detailed characterization of the material behaviour in unsaturated conditions was carried out. Experiments were designed in order to highlight the response of the involved soil in terms of changes in matric suction an…
Artificial Neural Networks for Predicting the Water Retention Curve of Sicilian Agricultural Soils
2018
Modeling soil-water regime and solute transport in the vadose zone is strategic for estimating agricultural productivity and optimizing irrigation water management. Direct measurements of soil hydraulic properties, i.e., the water retention curve and the hydraulic conductivity function, are often expensive and time-consuming, and represent a major obstacle to the application of simulation models. As a result, there is a great interest in developing pedotransfer functions (PTFs) that predict the soil hydraulic properties from more easily measured and/or routinely surveyed soil data, such as particle size distribution, bulk density (&rho
Using static and dynamic indicators to evaluate soil physical quality in a Sicilian area
2016
Both capacitive indicators derived from the water retention curve and dynamic measurements of the flow-weighted mean pore radius, R0, were used to assess the soil physical quality of two agricultural areas (cropland and olive orchard) and two natural areas (grassland and managed woodlot plantation) potentially subject to soil degradation. The overall idea of the study was to investigate whether a dynamic indicator quantitatively derived from hydraulic conductivity measurements could be used to supplement the traditionally applied capacitive indicators retrieved from water retention measurements. According to the available criteria, only the surface layer of the cropland site showed optimal …
Effects of pyrolysis temperature on the hydrologically relevant porosity of willow biochar
2018
Biochar pore space consists of porosity of multiple length scales. In direct water holding applications like water storage for plant water uptake, the main interest is in micrometre-range porosity since these pores are able to store water that is easily available for plants. Gas adsorption measurements which are commonly used to characterize the physical pore structure of biochars are not able to quantify this pore-size range. While pyrogenetic porosity (i.e. pores formed during pyrolysis process) tends to increase with elevated process temperature, it is uncertain whether this change affects the pore space capable to store plant available water. In this study, we characterized biochar poro…
BENEFICIOS RELACIONALES, SATISFACCIÓN Y LEALTAD EN EL COMERCIO MINORISTA: UNA COMPARATIVA INTERSECTORIAL
2009
RESUMENEn el contexto del marketing de relaciones, resulta de gran importancia para el establecimiento minorista identificar el tipo de beneficios de la relación que influye en mayor medida sobre sus resultados en términos de satisfacción del cliente y lealtad hacia el minorista, de manera que se garantice una relación continua y satisfactoria. Dichos beneficios pueden tener distinto peso en función del tipo de actividad llevada a cabo por el minorista. El presente trabajo pretende analizar empíricamente un modelo que refleje los distintos tipos de beneficios relacionales obtenidos por los clientes, así como los beneficios obtenidos por la organización en términos de lealtad del consumidor …
The Mechanical Impact of Water Affected the Soil Physical Quality of a Loam Soil under Minimum Tillage and No-Tillage: An Assessment Using Beerkan Mu…
2021
The multi-height (low, L = 3 cm