Search results for "Moisture"
showing 10 items of 290 documents
Indirect estimation of calibration equation parameters for Sentek Diviner 2000 capacitance probe by means of soil physical properties
2014
Measurements of soil water content (SWC) are often used for irrigation scheduling. Accurate monitoring of SWC is necessary, for example, to identify the exact irrigation timing and the amount of water volume to supply according to the crop requirement. The use of capacitance probes, measuring the apparent soil dielectric permittivity, indirectly related to soil water status, have been increasing during the last decade, as proved by the numerous researches carried out to determine, for different soil types, site-specific calibration relationships between SWC and the scaled frequency (SF) measured by the sensor. However, for swelling/shrinking clay soils, there is a lack of knowledge on how t…
Subsurface drip irrigated potato (Solanum tuberosum L.) with saline water under Tunisian climate
2012
Field experiment was conducted at the Higher Institute of Agronomy of Chott Meriem (Tunisia) during the growing season (2011/2012) to investigate the effects of water quality on water‘s dynamic in soil (water potential, soilcmoisture distribution, water’s stock in soil) and water use efficiency (WUE) to produce potato (Solanum tuberosum L.). Irrigation management treatments were fresh (1 dS m-1) and saline waters (4 dS m-1). Subsurface drip irrigation was used, a rate of 4 L h-1 applied at the same irrigation duration and interval. The results indicate that water content is more uniform using the saline water varies from 15 to 23% than treatment varies from 10 to 26%. The recorded changes o…
Hatching Success of Caretta caretta on a Mediterranean Volcanic Beach: Impacts from Environmental Parameters and Substrate Composition
2022
New data on the potential impact of environmental parameters and the mineralogical nature of the substrate on the hatching success of the loggerhead sea turtle Caretta caretta on a volcanic beach on Linosa Island in the central Mediterranean Sea are reported. During 2 years of investigation (2018-19), five nests were observed. The temperature and moisture of the nests were determined along with the grain size and mineralogical nature of the substrate. The temperature values of the nests recorded at depths of 5 and 35 cm showed an average temperature incubation of 32.2°C ± 1.4°C and 32.8°C ± 1.6°C, respectively, with peaks close to 37°C. The sedimentological analysis carried out on two cores…
Mathematical modelling of biogas from municipal solid waste landfil
2016
Sanitary landfills for municipal solid wastes can be considered as large biological reactors where the organic fraction of municipal solid waste undergoes anaerobic digestion producing gas and liquid emissions. Leachate production from municipal sanitary landfills is currently recognized as a major environmental burden associated with municipal solid waste management and it may be responsible for local pollution of groundwater and soil. Moreover, the fate of the organic compounds within the landfill body is of primary importance since it directly influences the production of landfill gas. The aim of the paper is to propose an integrated mathematical model able to simulate, on one hand, the …
Rubberised stone mastic asphalt mixtures: a performance-related evaluation
2022
The binder content of rubberised asphalt mixtures is usually increased compared to that used in conventional asphalt. This increase is deemed important to compensate for the reduction in the actual bitumen due to the existence of rubber particles. This study presents the results of performance evaluation conducted on different rubberised Stone Mastic Asphalt (SMA) mixtures produced using different types and contents of rubberised bitumen. The energy ratio (ER) computed from Superpave Indirect Tensile (IDT) tests was used to evaluate the cracking resistance of asphalt mixtures while the rutting behaviour was evaluated using the Repeated Load Axial Test (RLAT). The indirect tensile stiffness …
Assessment of performance degradation of hybrid flax-glass fiber reinforced epoxy composites during a salt spray fog/dry aging cycle
2022
The main goal of this paper is the evaluation of the performances reversibility of hybrid composites when they are dried after being aged in salt-fog environment. To this aim, epoxy composites reinforced with flax and glass fabrics respectively in the internal and external laminae were at first exposed to salt-fog (i.e., identified as wet phase) and then stored in controlled conditions (i.e., identified as dry phase). The flexural properties evolution of these composites as well as their water uptake and contact angle were monitored at varying time of both phases. The flexural strength and modulus of hybrid composites is 23.4% (17.9%) and 15.5% (12.9%) lower than unaged ones after 30 (15) d…
Flax–Glass Fiber Reinforced Hybrid Composites Exposed to a Salt-Fog/Dry Cycle: A Simplified Approach to Predict Their Performance Recovery
2023
Despite natural fibers gaining significant attention in recent decades, their limited performance and poor durability under humid environments cannot allow them to fully replace their synthetic counterparts as reinforcement for structural composites. In such a context, this paper aims to investigate how exposure to a humid/dry cycle affects the mechanical response of epoxy laminates reinforced with flax and glass fibers. In particular, the main goal is to assess the performance evolution of a glass–flax hybridized stacking sequence in comparison with the full glass and flax fiber reinforced composites. To this end, the investigated composites were first exposed to salt-fog for 15 or 30 days…
Deep Gaussian processes for biogeophysical parameter retrieval and model inversion
2020
Parameter retrieval and model inversion are key problems in remote sensing and Earth observation. Currently, different approximations exist: a direct, yet costly, inversion of radiative transfer models (RTMs); the statistical inversion with in situ data that often results in problems with extrapolation outside the study area; and the most widely adopted hybrid modeling by which statistical models, mostly nonlinear and non-parametric machine learning algorithms, are applied to invert RTM simulations. We will focus on the latter. Among the different existing algorithms, in the last decade kernel based methods, and Gaussian Processes (GPs) in particular, have provided useful and informative so…
Synergistic integration of optical and microwave satellite data for crop yield estimation
2019
Developing accurate models of crop stress, phenology and productivity is of paramount importance, given the increasing need of food. Earth observation (EO) remote sensing data provides a unique source of information to monitor crops in a temporally resolved and spatially explicit way. In this study, we propose the combination of multisensor (optical and microwave) remote sensing data for crop yield estimation and forecasting using two novel approaches. We first propose the lag between Enhanced Vegetation Index (EVI) derived from MODIS and Vegetation Optical Depth (VOD) derived from SMAP as a new joint metric combining the information from the two satellite sensors in a unique feature or des…
SENTINEL-1 for wheat mapping and soil moisture retrieval
2015
The main objective of this study is to assess the use of Sentinel-1 (S-1) data for surface soil moisture (SSM) retrieval and wheat mapping (WM) at high spatial resolution (e.g. 100–500m), which constitute valuable information for improving crop yield forecast at large scale. A knowledge based classification method and a SSM retrieval algorithm, developed in view of the European Space Agency Sentinel-1 mission, have been applied to a time series of S-1A data collected from October 2014 to April 2015 over a well-documented agricultural site in southern Italy. In particular, observations of SSM content recorded by a network of ground stations deployed in an experimental farm have been used to …