Search results for "Water uptake"
showing 10 items of 14 documents
Thermal and Mechanical Characterization of Yarn Samples from Flemish Tapestry of the Sixteenth Century
2022
We propose a physico-chemical approach for theharacterization of the conservation condition of yarns from a Flemish tapestry of the sixteenth century. The aging effect on the yarns’ performance was evaluated by comparison with commercial materials. Water uptake experiments highlighted the aptitude of yarns toward water sorption and their increased hydrophilicity upon aging. Thermogravimetric analysis can be considered a fast approach for the fiber identification and assessment on the material life-time. The dynamic mechanical analysis provided direct evidence on the yarns, conservation state and their performance under different mechanical stresses. The proposed characterization path can be…
Prise en eau par composites carbone/époxy et leur effet sur le comportement mécanique : application aux réparations de structures en composite par co…
2013
Le travail présenté dans ce mémoire avait pour objectif d’étudier le processus de la pénétration d'eau dans les composites en carbone/époxyde dans un premier temps, et dans un deuxième temps, d’étudier l’effet de la prise en eau par ces matériaux sur les performances mécaniques des composites et leur joints collés. L'intégration de ces phénomènes physiques dans la modélisation numérique est d'une grande importance dans la prédiction de la durabilité d’une structure en composite subissant un vieillissement hygrothermique. Par conséquent, ce travail consiste non seulement en des observations expérimentales, mais aussi en des simulations numériques. Des corrélations entre les résultats obtenus…
Variations in soil-water use by grapevine according to plant water status and soil physical-chemical characteristics - A 3D spatio-temporal analysis.
2016
14 pages; International audience; Understanding plant and soil-water relationships is crucial to optimise agricultural management. In this multidisciplinary work, soil geophysics and plant physiological measurements are coupled and a statistical method is proposed to visualising plant soil-water uptake in space and time. The method is applied in a vineyard context and shows differences in the use of tranpirable soil water by grapevine according to the type of soil and the time of the day (day/night).During two years the water stress experienced by a single Chardonnay/SO4 grapevine clone was monitored both at pre-dawn and midday by leaf water potentials in two field plots exclusively differe…
Detecting crop water requirement indicators in irrigated agroecosystems from soil water content profiles: An application for a citrus orchard.
2022
Abstract Most perennial crops sensitive to water scarcity, such as citrus, can benefit from efficient water management, which allows for reduced water consumption while increasing crop production on a long-term basis. However, when implementing water-saving strategies, it is necessary to monitor soil and/or plant water status in order to determine crop water demand. A plethora of devices providing indirect measurements of volumetric soil water content, such as the “drill and drop” multi-sensors probes (Sentek, Inc., Stepney, Australia), have been developed over the last decade. The objective of the paper was to analyse time-series of soil water content profiles and meteorological data colle…
Improvement of FAO-56 Model to Estimate Transpiration Fluxes of Drought Tolerant Crops under Soil Water Deficit: Application for Olive Groves
2014
[EN] Agro-hydrological models are considered an economic and simple tool for quantifying crop water requirements. In the last two decades, agro-hydrological physically based models have been developed to simulate mass and energy exchange processes in the soil-plant-atmosphere system. Although very reliable, because of the high number of required variables, simplified models have been proposed to quantify crop water consumes. The main aim of this paper is to propose an amendment of the Food and Agricultural Organization (FAO) of the United Nations FAO-56 spreadsheet program to introduce a more realistic shape of the stress function, valid for mature olive orchards (Olea europaea L.). The mod…
Effect of ion exchange capacity and water uptake on hydroxide transport in PSU-TMA membranes: A DFT and molecular dynamics study
2020
Abstract Anion Exchange Membranes (AEMs) are nowadays used in a very wide range of different applications, from electrodialytic systems for water treatment, to Fuel Cells for energy generation. In many of these cases, the AEM is in contact with water molecules, either in aqueous or gas phase, which can strongly interact with the AEM polymer, thus affecting membrane properties. The role of water in fully swollen AEM and its effect on the diffusion of hydroxide is the focus of this work. Density Functional Theory (DFT) based calculations were merged with Molecular Dynamics (MD) simulations coming to a more accurate description of the ionic exchange capacity effect on the hydroxide ion diffusi…
Physical Aspects of the Atmospheric Aerosol
1982
The atmospheric aerosol is a trace substance of the troposhere as well as the trace gases. Therefore a number of similiarities should be expected. As an example a common model on residence time is developed and discussed in its results. The residence time connects the content of a reservoir (size distribution for aerosols) with its source strength or removal rate. This is presented for the aerosol. In addition other physical properties of the tropospheric aerosol like optical, electrical and water uptake properties are discussed.
The use of soil electrical resistivity to monitor plant and soil water relationships in vineyards
2015
Abstract. Soil water availability deeply affects plant physiology. In viticulture it is considered as a major contributor to the "terroir" expression. The assessment of soil water in field conditions is a difficult task especially over large surfaces. New techniques, are therefore required to better explore variations of soil water content in space and time with low disturbance and with great precision. Electrical Resistivity Tomography (ERT) meets these requirements, for applications in plant sciences, agriculture and ecology. In this paper, possible techniques to develop models that allow the use of ERT to spatialise soil water available to plants are reviewed. An application of soil wate…
The impact of the volumetric swelling behavior on the water uptake of gas shale
2018
Abstract Water uptake of gas shales is commonly considered one of the most important factors responsible for fluid loss during flowback operations after hydraulic fracturing. Imbibition experiments cover a key role in this context to analyze the impact of several factors (such as mineralogical composition, fluids composition, anisotropic structure, volumetric swelling) that contribute to the water uptake in these unconventional reservoirs. The aim of this study is the quantification of the impact of the volumetric response (swelling and shrinkage) of gas shales on the water uptake during imbibition and desiccation processes. An experimental methodology to quantify the volumetric response du…
Water uptake and equilibrium sizes of aerosol particles at high relative humidities: Their dependence on the composition of the water-soluble material
1978
Equilibrium water uptake and the sizes of atmospheric aerosol particles have for the first time been determined for high relative humidities, i.e., for humidities above 95 percent, as a function of the particles chemical composition. For that purpose a new treatment of the osmotic coefficient has been developed and experimentally confirmed. It is shown that the equilibrium water uptake and the equilibrium sizes of atmospheric aerosol particles at large relative humidities are significantly dependent on their chemical composition.