Radar track segmentation with cubic splines for collision risk models in high density terminal areas

This paper presents a method to segment airplane radar tracks in high density terminal areas where the air traffic follows trajectories with several changes in heading, speed and altitude. The radar tracks are modelled with different types of segments, straight lines, cubic spline function and shape preserving cubic function. The longitudinal, lateral and vertical deviations are calculated for terminal manoeuvring area scenarios. The most promising model of the radar tracks resulted from a mixed interpolation using straight lines for linear segments and spline cubic functions for curved segments. A sensitivity analysis is used to optimise the size of the window for the segmentation process

Neutrino-induced reactions in core-collapse supernovae: Effects on the electron fraction

Neutrino-induced reactions are a basic ingredient in astrophysical processes like star evolution. The existence of neutrino oscillations affects the rate of nuclear electroweak decays which participates in the chain of events that determines the fate of the star. Among the processes of interest, the production of heavy elements in core-collapse supernovae is strongly dependent upon neutrino properties, like the mixing between different species of neutrinos. In this work, we study the effects of neutrino oscillations upon the electron fraction as a function of the neutrino mixing parameters, for two schemes: the 1+1-scheme (one active neutrino and one sterile neutrino) and the 2+1-scheme (two active neutrinos and one sterile neutrino). We have performed this analysis considering a core-collapse supernovae and determined the physical conditions needed to activate the nuclear reaction chains involved in the r-process. We found that the interactions of the neutrinos with matter and among themselves and the initial amount of sterile neutrinos in the neutrino-sphere might change the electron fraction, therefore affecting the onset of the r-process. We have set constrains on the active-sterile neutrino mixing parameters. They are the square-mass-difference ∆m^2_14 , the mixing angle sin^2(2θ_14), and the hindrance factor Xi_s for the occupation of sterile neutrinos. The calculations have been performed for different values of X_alpha, which is the fraction of alpha particles. For X_alpha=0 the r-process is taking place if ∆m^2_14 ≥ 2 eV^2 , sin^2(2θ_14) < 0.8 and Xi_s < 0.5. For larger values of X_alpha the region of parameters is strongly reduced. The present results are compared to results available in the literature.Fil: Saez, M. M.. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Civitarese, Enrique Osvaldo. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Mosquera, Mercedes Elisa. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Neutrino-induced reactions in core-collapse supernovae : Effects on the electron fraction

Neutrino-induced reactions are a basic ingredient in astrophysical processes like star evolution. The existence of neutrino oscillations affects the rate of nuclear electroweak decays which participates in the chain of events that determines the fate of the star. Among the processes of interest, the production of heavy elements in core-collapse supernovae is strongly dependent upon neutrino properties, like the mixing between different species of neutrinos. In this work, we study the effects of neutrino oscillations upon the electron fraction as a function of the neutrino mixing parameters, for two schemes: the 1+1-scheme (one active neutrino and one sterile neutrino) and the 2+1-scheme (two active neutrinos and one sterile neutrino). We have performed this analysis considering a core-collapse supernovae and determined the physical conditions needed to activate the nuclear reaction chains involved in the r-process. We found that the interactions of the neutrinos with matter and among themselves and the initial amount of sterile neutrinos in the neutrino-sphere might change the electron fraction, therefore affecting the onset of the r-process. We have set constrains on the active-sterile neutrino mixing parameters. They are the square-mass-difference Δm142 , the mixing angle sin2214, and the hindrance factor ξs for the occupation of sterile neutrinos. The calculations have been performed for different values of Xα, which is the fraction of alpha particles. For Xα=0 the r-process is taking place if Δm142≥2eV2, sin22140.8 and ξs0.5. For larger values of Xα the region of parameters is strongly reduced. The present results are compared to results available in the literature.Facultad de Ciencias Astronómicas y GeofísicasFacultad de Ciencias ExactasInstituto de Física La Plat

T0901317 is a potent PXR ligand: Implications for the biology ascribed to LXR

AbstractThe liver X receptors (LXRα and β) are nuclear receptors that coordinate carbohydrate and lipid metabolism. Insight into the physiologic roles of the LXRs has been greatly facilitated by the discovery of potent synthetic agonists. Here we show that one of these compounds, T0901317, is also a high-affinity ligand for the xenobiotic receptor pregnane X receptor (PXR). T0901317 binds and activates PXR with the same nanomolar potency with which it stimulates LXR activity. T0901317 induces expression not only of LXR target genes, but also of PXR target genes in cells and animals, including the scavenger receptor CD36, a property not shared by more specific LXR ligands, such as GW3965. Activation of PXR targets may explain why T0901317 induces dramatic liver steatosis, while GW3965 has a milder effect. These results suggest that many of the biological activities heretofore associated with LXR activation may be mediated by PXR, not LXR. Since T0901317 has been widely used in animals to study LXR function, the in vivo effects of this compound ascribed to LXR activation should be re-examined

Numerical analysis of interlaminar stresses in open-hole laminates under compression

In this paper, the interlaminar stresses in open-hole laminates subjected to compressive loads are analysed using a numerical model. This model implements the Serial/Parallel Mixing Theory (S/PMT) and a Continuum Damage Mechanics (CDM) approach. The S/PMT estimates the global stiffness in the laminate from fibre and matrix properties. The CDM approach models the damage initiation due to fibre microbuckling. The global response estimated by the model was verified with experimental data from the literature. The model predicts that the damage initiates in the laminate middle-plane where the thickest block of plies oriented in the load direction is located, and progressively propagates to the nearest block of layers with the same orientation. Two laminate stacking sequences were analysed. The interlaminar stresses around the hole presented symmetry with respect to the load direction and the perpendicular axis, being located the maximum and minimum values in different angular positions for each stress component and laminate.Postprint (published version

The influence of acoustic standards in construction: a case study of social housing in Argentina

[EN] Exposure to high noise levels greatly impacts human health. For this reason, it is necessary to take into account the acoustic conditioning of built interior spaces, since human beings spend a large part of their time in them. To this end, each country must regulate and promote good construction practices that guarantee the mental and physical comfort of its occupants. In the case of Argentina, there is an insufficiency in the development of laws and regulations on acoustic architecture and even more so on acoustics in homes. In this sense, this study aims to evaluate the current acoustic comfort presented by public housing in Argentina, highlighting the existing legal gaps, and enabling recommendations in this regard, taking Spain as the country of reference. This country is taken since Argentine legislation has traditionally replicated European and Spanish standards instead of American ones. To this end, a systemic review and comparison are made between the laws and architectural acoustic regulations of Argentina and Spain. The observation of the noise protection standards in closed areas of these countries will be deepened. For a better understanding of these and to meet the objective, a prototype of public housing was needed in different parts of the country through the PRO.CRE.AR plan is taken as a case study and verified according to each standard. IRAM and UNE. As a relevant result, it is shown that the houses built by the State only partially verify the admissible minimums proposed by the regulations. The lack of laws and complementary documents focused on acoustic conditioning is concluded through the case study.Saez, V.; Quintana Gallardo, A.; Garzón, B.; Guillén Guillamón, IE. (2023). The influence of acoustic standards in construction: a case study of social housing in Argentina. Editorial Universitat Politècnica de València. 588-596. https://doi.org/10.4995/VIBRArch2022.2022.1520458859

ACOR: Adaptive congestion-oblivious routing in dragonfly networks

Low-diameter network topologies require non-minimal routing to avoid network congestion, such as Valiant routing. This increases base latency but avoids congestion issues. Optimized restricted variants focus on reducing path length. However, these optimizations only reduce paths for local traffic, where source and destination of each packet belong to the same partition of the network. This paper introduces ACOR: Adaptive Congestion-Oblivious Routing. ACOR leverages the restricted and recomputation mechanisms to reduce path length for local and global traffic, and extends it when the network conditions are adverse. ACOR relies on a sequence of misrouting policies ordered by path length. A hysteresis mechanism improves performance and avoids variability in the results. The ACOR mechanism can be combined with other non-minimal routing mechanism such as Piggyback. Results show that ACOR improves base latency in all cases, up to 28% standalone and up to 25.5% when combined with Piggyback, while requiring a simple implementation.This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness under contract TIN2016-76635-C2-2-R (AEI/FEDER, UE), the European HiPEAC Network of Excellence and The Mont-Blanc project, which has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 671697

Numerical and experimental characterization of the hydrodynamics and drying kinetics of a barbotine slurry spray

Spray drying is a basic unit operation in several process industries such as food, pharmaceutical, ceramic, and others. In this work, a Eulerian-Lagrangian three-phase simulation is presented to study the drying process of barbotine slurry droplets for the production of ceramic tiles. To this end, the simulated velocity field produced by a spray nozzle located at the Institute of Ceramic Technology in Castelló (Spain) is benchmarked against measurements obtained by means of laser Doppler anemometry in order to validate the numerical model. Also, the droplet size distribution generated by the nozzle is obtained at operating conditions by means of laser diffraction and the data obtained are compared qualitatively to those found in the literature. The characteristic Rosin-Rammler droplet size from the distribution is introduced thereafter in the three-phase simulation to analyse the drying kinetics of individual droplets. The model predicts the theoretical linear evolution of the square diameter (D2-law), and the temperature and mass exchange with the environment. The proposed model is intended to support the design and optimization of industrial spray dryers

The vibrational spectrum of Nd<SUB>2</SUB>BaCuO<SUB>5</SUB>

Compounds of general composition Ln2BaCuO5 (Ln=lanthanide) adopt different structural types. Two series of structures have been reported for LnzBaCuO5 compounds. For lanthanide ions smaller than Nd(III) (Y and Sm-Lu) the so-called "green phases" (orthorhombic, space group Pbnm) are stabilized. They are one of the main impurities generated during the synthesis of the LnBa2Cu3OT_x-type high-T¢ superconducting oxides. A different structural type (tetragonal, space group P4/mbm) becomes stabilized for Ln = La or Nd, although in the case of the lanthanum-containing material the totally stoichiometric composition does not seem to be attainable.Facultad de Ciencias Exacta

Throughput Unfairness in Dragonfly Networks under Realistic Traffic Patterns

Dragonfly networks have a two-level hierarchical arrangement of the network routers, and allow for a competitive cost-performance solution in large systems. Nonminimal adaptive routing is employed to fully exploit the path diversity and increase the performance under adversarial traffic patterns. Throughput unfairness prevents a balanced use of the resources across the network nodes and degrades severely the performance of any application running on an affected node. Previous works have demonstrated the presence of throughput unfairness in Dragonflies under certain adversarial traffic patterns, and proposed different alternatives to effectively combat such effect. In this paper we introduce a new traffic pattern denoted adversarial consecutive (ADVc), which portrays a real use case, and evaluate its impact on network performance and throughput fairness. This traffic pattern is the most adversarial in terms of network fairness. Our evaluations, both with or without transit-over-injection priority, show that global misrouting policies do not properly alleviate this problem. Therefore, explicit fairness mechanisms are required for these networks