Search results for " costruzioni"
showing 10 items of 1626 documents
Actual evapotranspiration assessment in a sparse tall Mediterranean crops
2010
Comparing actual evapotranspiration and plant water potential on a vineyard
2011
Agricultural water requirement in arid and semi-arid environments represents an important fraction of the total water consumption, suggesting the need of appropriate water management practices to sparingly use the resource. Furthermore the quality and quantity of some crops products, such as grape, is improved under a controlled amount of water stress. The latter is related, on a side to actual evapotranspiration (ET) through water demand, on the other side to plant water content through leaf water potential. Residual energy balance approaches based on remote sensing allow to estimate the spatial distribution of daily actual ET at plant scale, representing an useful tool to detect its spati…
Actual evapotranspiration assessment by means of a coupled energy/hydrologic balance model: Validation over an olive grove by means of scintillometry…
2010
Summary A coupled energy/hydrologic model was applied to simulate the exchange of energy and water in the soil–plant-atmosphere system (SPA). The model, which uses a “two-source” approach to estimate the energy fluxes, and the “force-restore” approach to represent the water balance, was validated by means of evapotranspiration measurements collected via scintillometry and soil moisture measurements collected via time domain reflectometry (TDR) in a Sicilian olive grove. The comparison between measured and estimated fluxes values at an hourly scale showed good agreement. Additional comparisons on a daily timescale confirmed the model’s applicability for quantifying crop water requirements. A…
Spatial sharpening of land surface temperature for daily energy balance applications
2008
ABSTRACT Daily high spatial resolution assessment of actual evapotranspiration is essential for water management and crop water requirement estimation under stress conditions. The application of energy balance models usually requires satellite observations of radiometric surface temperat ure with high geometrical and temporal resolutions. By now, however, high spatial resolution (~ 100 m) is available with low time fre quency (approximately every two weeks); at the opposite daily acquisition are characterised by poor spatial resolution. The analysis of vegetation index (VI) and land surface temperature (LST) spatial relationship, shows in substance a scale invariant behaviour [1] ; this con…
Applications of a remote sensing-based two-source energy balance algorithm for mapping surface fluxes without in situ air temperature observations
2012
Abstract The two-source energy balance (TSEB) model uses remotely sensed maps of land–surface temperature (LST) along with local air temperature estimates at a nominal blending height to model heat and water fluxes across a landscape, partitioned between dual sources of canopy and soil. For operational implementation of TSEB, however, it is often difficult to obtain representative air temperature data that are compatible with the LST retrievals, which may themselves have residual errors due to atmospheric and emissivity corrections. To address this issue, two different strategies in applying the TSEB model without requiring local air temperature data were tested over a typical Mediterranean…
Analysis of energy fluxes estimations over Italy using time-differencing models based on thermal remote sensing data
2012
Large area estimations of land surface fluxes can be a useful operational tool for up-scaling local measurements and can serve as an upper-boundary condition for higher spatial resolution applications. Given hourly measurements of radiometric surface temperature from a geostationary satellite, it is possible to derive the partitioning of energy fluxes based on the influence of the evapotranspiration process on morning surface temperature rise. In this work, the Atmosphere-Land Exchange Inverse (ALEXI) model and the Dual Temperature Difference (DTD) approach were applied in order to relate the sensible heat flux to time-differential remote observations of surface temperature obtained from Me…
Optimization design process of a morphing winglet
2018
Aeronautic and aerospace engineering is recently moving in the direction of developing morphing wing devices, with the aim of making adaptable the aerodynamic shapes to different operational conditions. Those devices may be classified according to two different conceptual architectures: kinematic or compliant systems. Both of them embed within their body all the active components (actuators and sensors), necessary to their operations. In the first case, the geometry variation is achieved through an augmented classical mechanism, while in the second case the form modification is due to a special arrangement of the inner structure creating a distributed elastic hinges arrangement. Whatever is…
Evaluation of aging behavior under salt-fog spray conditions of green sandwich structures
2018
In this paper, the aging resistance of sandwich structures made with cork agglomerate as core and flax-reinforced polymeric laminates as face sheets was investigated for the first time. In order to evaluate their durability in a hostile environment, a sandwich plate was manufactured by vacuum bagging technique and aged under salt-fog spray conditions, according to ASTM B 117 standard. The evolution of the sandwich mechanical properties during the aging exposition was analyzed by carrying out quasi-static flexural tests and Charpy impact tests both on unaged specimens and on specimens aged for 10, 25, and 60 days, respectively. The quasi-static experimental results showed that despite the sa…
Effects of Air Tightness Tests on Steel Thin-Wall Box Structures with Circular and Rectangular Cross Sections
2019
In this paper, the effects of air tightness tests on steel box structures with rectangular or circular cross sections typical of port cranes (legs, arms, and crosspieces) are analyzed. Legs and arms are generally made with elements with profiles having a square or rectangular cross section, while the diagonal struts are made with profiles having circular cross sections. To verify the air tightness of these elements, a necessary requirement to protect them from corrosion if they are not protected with other protection techniques, air tightness tests are performed. These tests, in the framework of durability tests, must be carried out while maintaining the structure elasticity well below the …
DEVELOPMENT AND APPLICATIONS OF A VIRTUAL HYBRID PLATFORM FOR MULTISCALE ANALYSIS OF ADVANCED STRUCTURES OF AIRCRAFT (DEVISU)
2022
This paper outlines the main findings of the project “DEvelopment and applications of a VIrtual hybrid platform for multiscale analysis of advanced StructUres of aircraft” (DEVISU), which deals with failure of composite structures and noise/vibration reduction, along with investigation of new materials for aerospace applications.