Scalable Parallel Numerical CSP Solver

We present a parallel solver for numerical constraint satisfaction problems (NCSPs) that can scale on a number of cores. Our proposed method runs worker solvers on the available cores and simultaneously the workers cooperate for the search space distribution and balancing. In the experiments, we attained up to 119-fold speedup using 256 cores of a parallel computer.Comment: The final publication is available at Springe

High strain rate behavior of aluminum die cast components

Abstract Research results of static and dynamic mechanical tests (ɛ = 1 * 10-3 s-1 and ɛ ~ 5 * 102 s-1 conducted on samples obtained from three different die cast products (component A, B and C) of AlSi10MnMg alloy are reported. All the components have thin-walled geometry except some thicker positions of component C. The dynamic (high strain rate) mechanical characterization shows an increase of tensile properties, in respect to static tensile ones (tensile strength increases approximately 15%, and the yield strength 30%, for all the die cast components) together with an evident plastic deformation, with consequent necked region in the fractured section, substantially negligible in case of static tensile tests. Moreover, fractographic observations are conducted on specimens undergone static and high strain rate test conditions, to observe the fracture morphology, together with metallographic analysis on the only polished or etched transverse specimens to reveal the porosity, and the microstructure of dendrite and inter-dendrite morphologies

Improvement of resveratrol permeation through sublingual mucosa: Chemical permeation enhancers versus spray drying technique to obtain fast-disintegrating sublingual mini-tablets

Resveratrol (RSV) is a natural polyphenol with several interesting broad-spectrum pharmacological properties. However, it is characterized by poor oral bioavailability, extensive first-pass effect metabolism and low stability. Indeed, RSV could benefit from the advantage of the sublingual route of administration. In this view, RSV attitudes to crossing the porcine sublingual mucosa were evaluated and promoted both by six different chemical permeation enhancers (CPEs) as well as by preparing four innovative fast-disintegrating sublingual mini-tablets by spray drying followed by direct compression. Since RSV by itself exhibits a low permeation aptitude, this could be significantly enhanced by the use of CPEs as well as by embedding RSV in a spray-dried powder to be compressed in order to prepare fast-disintegrating mini-tablets. The most promising observed CPEs (menthol, lysine and urea) were then inserted into the most promising spray-dried excipients’ compositions (RSV-B and RSV-C), thus preparing CPE-loaded mini-tablets. However, this procedure leads to unsatisfactory results which preclude the possibility of merging the two proposed approaches. Finally, the best spray-dried composition (RSV-B) was further evaluated by SEM, FTIR, XRD and disintegration as well as dissolution behavior to prove its effectiveness as a sublingual fast-disintegrating formulation

Machine learning models to predict daily actual evapotranspiration of citrus orchards under regulated deficit irrigation

Precise estimations of actual evapotranspiration (ETa) are essential for various environmental issues, including those related to agricultural ecosystem sustainability and water management. Indeed, the increasing demands of agricultural production, coupled with increasingly frequent drought events in many parts of the world, necessitate a more careful evaluation of crop water requirements. Artificial Intelligence-based models represent a promising alternative to the most common measurement techniques, e.g. using expensive Eddy Covariance (EC) towers. In this context, the main challenges are choosing the best possible model and selecting the most representative features. The objective of this research is to evaluate two different machine learning algorithms, namely Multi-Layer Perceptron (MLP) and Random Forest (RF), to predict daily actual evapotranspiration (ETa) in a citrus orchard typical of the Mediterranean ecosystem using different feature combinations. With many features available coming from various infield sensors, a thorough analysis was performed to measure feature importance, scatter matrix observations, and Pearson's correlation coefficient calculation, which resulted in the selection of 12 promising feature combinations. The models were calibrated under regulated deficit irrigation (RDI) conditions to estimate ETa and save irrigation water. On average up to 38.5% water savings were obtained, compared to full irrigation. Moreover, among the different input variables adopted, the soil water content (SWC) feature appears to have a prominent role in the prediction of ETa. Indeed, the presented results show that by choosing the appropriate input features, the accuracy of the proposed machine learning models remains acceptable even when the number of features is reduced to only 4. The best performance was achieved by the Random Forest method, with seven input features, obtaining a root mean square error (RMSE) and a coefficient of determination (R2) of 0.39 mm/day and 0.84, respectively. Finally, the results show that the joint use of SWC, weather and satellite data significantly improves the performance of evapotranspiration forecasts compared to models using only meteorological variables

^(40)K–^(40)Ca isotopic constraints on the oceanic calcium cycle

The contributions of crustal silicates to the oceanic calcium cycle are investigated using high-precision ^(40)K–^(40)Ca measurements in Archean and Proterozoic carbonates, river waters, and a series of terrestrial and extraterrestrial mafic/ultramafic samples. Using a multidynamic data collection scheme with strict controls on instrumental mass fractionation, we show that a reproducibility of 0.35 ε-units (2σ) is obtained for the ^(40)Ca/^(44)Ca ratio using the ThermoFinnigan Triton. This represents an improvement by a factor of 3 compared with previous generations of data. Well-defined excesses of ^(40)Ca from ^(40)K decay were found in river waters draining the Himalayas, but not in the Mississippi and Columbia Rivers. All marine carbonate samples ranging in age from Archean to recent show no discernable effects of ^(40)K decay to within the limit of ± 0.35 ε-units (2σ) in ^(40)Ca/^(44)Ca. Our results, therefore, indicate that the Ca isotopic composition of seawater has remained constant and indistinguishable from that of the mantle for the past 3.5 Ga, despite the influx of radiogenic calcium delivered by weathering of the high K/Ca components of the continental crust. Thus, over most of geologic time, the contributions of the high K/Ca sources from the continents are far below the contributions of hydrothermal sources. Mass balance constraints indicate that unless the present-day contribution of continental silicates is much less than 8% of the river Ca flux, the total hydrothermal flux of calcium must exceed the input from high-temperature vents at ridge axes by at least one order of magnitude. The present-day oceanic mass balance requires a high input of calcium [(4–15) × 10^(12) mol Ca/yr] at low-temperature hydrothermal sites

Nature and evolution of the dominant carbonaceous matter in interplanetary dust particles: effects of irradiation and identification with a type of amorphous carbon

Aims.Interplanetary dust particle (IDP) matter probably evolved under irradiation in the interstellar medium (ISM) and the solar nebula. Currently IDPs are exposed to irradiation in the Solar System. Here the effects of UV and proton processing on IDP matter are studied experimentally. The structure and chemical composition of the bulk of carbon matter in IDPs is characterized. Methods: .Several IDPs were further irradiated in the laboratory using ultraviolet (UV) photons and protons in order to study the effects of such processing. By means of infrared and Raman spectroscopy, IDPs were also compared to different materials that serve as analogs of carbon grains in the dense and diffuse ISM. Results: .The carbonaceous fraction of IDPs is dehydrogenated by exposure to hard UV photons or 1 MeV protons. On the other hand, proton irradiation at lower energies (20 keV) leads to an efficient hydrogenation of the carbonaceous IDP matter. The dominant type of carbon in IDPs, observed with Raman and infrared spectroscopy, is found to be either a form of amorphous carbon (a-C) or hydrogenated amorphous carbon (a-C:H), depending on the IDP, consisting of aromatic units with an average domain size of 1.35 nm (5-6 rings in diameter), linked by aliphatic chains. Conclusions: .The D- and 15N-enrichments associated to an aliphatic component in some IDPs are probably the result of chemical reactions at cold temperatures. It is proposed that the amorphous carbon in IDPs was formed by energetic processing (UV photons and cosmic rays) of icy grains, maybe during the dense cloud stage, and more likely on the surface of the disk during the T Tauri phase of our Sun. This would explain the isotopic anomalies and morphology of IDPs. Partial annealing, 300-400°C, is required to convert an organic residue from ice photoprocessing into the amorphous carbon with low heteroatom content found in IDPs. Such annealing might have occurred as the particles approached the Sun and/or during atmospheric entry heating

First experimental test of Bell inequalities performed using a non-maximally entangled state

We report on the realisation of a new test of Bell inequalities using the superposition of type I parametric down conversion produced in two different non-linear crystals pumped by the same laser, but with different polarisation. The produced state is non-maximally entangled. We discuss the advantages and the possible developments of this configuration