Search results for "solution"
showing 10 items of 5638 documents
Spatial homogeneity from temporal stability: Exploiting the combined hyper-frequent revisit of Terra and Aqua to guide Earth System Science
2021
Abstract The terrestrial component of the Earth system has witnessed considerable changes in the past decades due to anthropogenic action. Throughout this period, the NASA Terra mission has been constantly monitoring the surface with the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. When combined with the MODIS instrument on-board of the Aqua platform, we obtain a hyper-frequent revisit capability providing sub-daily observations globally at a moderate resolution of ~250 m, but with a strong multi-angular variation of the observation footprint. Here we propose to exploit this particular configuration provided by the combined Terra + Aqua constellation to infer spatial ho…
<title>Multiresolution description of range images through 2D quincunx wavelet analysis</title>
1999
In this paper, we present a method for performing a multi- scale analysis on range images by using the wavelet transform, that is capable of revealing multi-resolution information. An accurate non-contact optical system based upon laser triangulation is used to determine the depth information of the object being scanned. The resulting range image is treated as a gray-level image by using a multi- resolution approach based on the generalization of the cascade algorithm using the quincunx wavelet transform. The quincunx wavelet assures very fine analysis. This method allows reconstruction of non-subsampled images that correspond to decompositions previously done at chosen scales. Multi-resolu…
Quality of Inclusive Educational System for Work with Students with Autism Different Needs in Italy
2015
The need for realization of inclusive education, which is the basis of a sustainable education, will require new challenges in the Education System. The system used in Italy can be used as an example. Italy passed avant-garde laws concerning the integration and inclusion of special needs students into the general school system already more than thirty years ago, in the 1970s. However, even after all this time and experience, there are still unresolved problems, which testifies to the complexities of the matter. This research offers an insight into the quality of the existing Italian inclusive education system specifically in relation to students with autism. Thereby it hopes to provide educ…
Monte Carlo dosimetric study of Best Industries and Alpha Omega Ir-192 brachytherapy seeds
2004
Ir-192 seeds are widely used in the USA for low dose rate interstitial brachytherapy. There are two commercially available models: those manufactured by Best Industries filtered with stainless steel, and those manufactured by Alpha-Omega seeds filtered with Pt. Newly developed 3D correction algorithms for brachytherapy are based on dosimetry data obtained on unbounded phantom size, allowing corrections for heterogeneities and actual tissue boundaries. Published dosimetric datasets for both seeds have been obtained under bounded conditions. The aim of the present study is to obtain dosimetric datasets for these seeds under full scatter conditions. The Monte Carlo GEANT4 code has been used to…
2-Aminopurine non-radiative decay and emission in aqueous solution: A theoretical study
2008
Abstract The minimum energy path along the lowest-lying ππ ∗ excited state of 2-aminopurine was calculated to elucidate the mechanisms of radiationless decay and emission in water. The sequential Monte Carlo quantum mechanics approach with a multiconfigurational and perturbative description of the wave function was employed to compute the minimum, transition state, and conical intersection. It was found that the barrier in the potential energy surface to access the conical intersection funnel increases in aqueous environment, making the system prone to enlarge the emission yield. These results rationalize the observed enhancement of emission in 2-aminopurine upon increasing of the solvent p…
Helical Shift Mechanics of Rubber V-Belt Variators
2011
A very common configuration of V-belt variators for motorcycles considers the correction of the belt tensioning depending on the resistant torque by means of suitable helical-shaped tracks allowing the driven half-pulleys to close/open. The theoretical model for belt-pulley coupling is rather complex for this configuration, where one half-pulley may run in advance and the other one behind with respect to the belt, and requires the repeated numerical solution of a strongly nonlinear differential system by a sort of shooting technique, until all the operating conditions are fulfilled (angular contact extent, torque, and axial force). After solving the full equations, the present study develop…
Aggregation of Free-Base Octacarboxyphthalocyanine in Aqueous Solutions
1999
Results of spectral (UV-VIS) investigations on the aggregation phenomena of the freebase 2,3,9,10,16,17,23,24-octacarboxypthalocyanine are reported. Phthalocyanine exists mainly in associated (aggregated) froms in water. The aggregates are present even in very diluted (10-7 -10-6 mol/dm-3) solutions. The hydrogen bonding between the carboxyl groups of the adjacent molecules in considered. The increase in pH and temperature, as well as the presence of the cationic surfactant and alcohols (in an appropriate quantity) cause a prtial or full disaggregation. The spectrum of the monomeric phthalocyanine from has been observed. The increase in H2Pc(COOH)8 concentration, the decrease in pH, as well…
Influence of Anion and Cation Structure of Ionic Liquids on Carboxylic Acids Extraction
2019
A recently proposed new mechanism and a model of reactive extraction of carboxylic acids by hydrophobic ionic liquids (ILs) was tested on five systems from published as well as from new equilibrium data on liquid-liquid extraction of butyric and lactic acids (BA and LA) from aqueous solutions. Two phosphonium and one ammonium ILs were used. The model describes experimental data for all systems with a good fit. The mechanism of acid extraction by ILs is very similar for all tested systems. This indicates a more general validity of the developed model. The model allows deeper understanding of regularities in carboxylic acid extraction by hydrophobic ILs. Stability constants of the first acid-…
Uptake of actinides by calcium silicate hydrate (C-S-H) phases
2018
Abstract The sorption of actinides (Th, U – Am) was studied in dependence of the solid-to-liquid (S/L) ratio (0.5–20.0 g/L) and the calcium-to-silicon (C:S) ratio. The C:S ratio was varied between 1.80 and 0.70 to simulate the changing composition of the C-S-H phases during cement degradation from high to low C:S ratios. The decrease of the calcium content in the C-S-H phases by time is accompanied by a decrease in pH in the corresponding suspensions from 12.6 to 10.2. X-ray photoelectron spectroscopy (XPS) of the C-S-H phases showed an increasing depletion of Ca on the surface with increasing C:S ratio in comparison to the composition of the solid phase as a whole. The sorption experiments…
Dual-Diameter Laterals in Center-Pivot Irrigation System
2022
Design strategies to enhance modern irrigation practices, reduce energy consumption, and improve water use efficiency and crop yields are fundamental for sustainability. Concerning Center-Pivot Irrigation Systems, different design procedures aimed at optimizing water use efficiency have been proposed. Recently, following a gradually decreasing sprinkler spacing along the pivot lateral with constant diameter and sprinkler flow rate, a new design method providing a uniform water application rate has been introduced. However, no suggestions were given to design multiple-diameter laterals characterized by different values of the inside pipe diameter. In this paper, first the previous design pro…