Molecular dynamics simulation of silver nanoparticles in a europium doped sodosilicate glass

Molecular dynamics simulation is applied to an europium doped sodosilicate glass containing silver [(Na–Ag)2O–SiO2–Eu2O3]. The silver is implanted in substitution of Na, simulating an ionic exchange. For ionic interactions a modified Born–Mayer–Huggins potential was employed. For the Ag–Ag interaction, a Lennard-Jones (LJ) potential is applied, while for the Eu–Ag interaction, a modified LJ potential is introduced. The particle size increases with the annealing treatment and follows a lognormal law. After 75 ps the average particle size reaches 5.8 atoms (4.8 for Ag and 1.0 for Eu), and it is found that the europium is preferentially situated on these nanoclusters

Molecular dynamics simulation and crystal field calculations of the Eu2O3-PbO-SiO2 glassy system submitted to long annealing time

The Eu2O3-PbO-SiO2 glassy system submitted to a long annealing time (100 ps) has been obtained by molecular dynamics calculations. The average of 87/86 sites of the Eu3 + ion with six/seven nearest neighbours are used to discuss the number of lines and the local symmetry of the luminescent site through the crystal field parameters, using the simple overlap model in the frame of the method of equivalent nearest neighbours. The magnitude of the [View the MathML source] Bq2(q = 0, 1, 2) and the non-negligible [View the MathML source] B44 and [View the MathML source] B46( [View the MathML source] B34, [View the MathML source] B36 and [View the MathML source] B66) lead to the indication of distorted C4h and C3i site symmetries of the six and seven nearest neighbours, respectively. We have then compared very satisfactorily our 7F1 sublevels calculations with those observed in the emission spectra of an Eu-borate glass annealed for 30 min and 17 h. This comparison is justified because the emission behaviour of europium ions in different glassy systems are honestly very similar. Further, the decrease observed in the 5D0→7F2/5D0→7F1 transition intensity ratio is a clear indication that the Eu3 + ion are nucleating a crystalline phase. Such satisfactory comparisons indicate that we have obtained a transparent glass-ceramics

AEMIP robust inversion using maximum phase angle Cole–Cole model re-parameterisation applied for HTEM survey over Lamego gold mine, Quadrilátero Ferrífero, MG, Brazil

This paper presents the results of airborne electromagnetic induced polarisation inversions using the Maximum Phase Angle (MPA) model for a helicopter time domain survey in the Quadril\ue1tero Ferr\uedfero area, Minas Gerais State (MG), Brazil. The inversions were conducted using a laterally constrained robust scheme, in order to decrease the difficulties to recover the multi-parametric model in a very ill-posed inverse problem, often found in induced polarisation studies. A set of six flight lines over the Lamego gold mine mineralised structure were inverted using the MPA re-parameterisation of the Cole\u2013Cole model and also the classical resistivity-only parameterisation, in order to understand the implications of the induced polarisation effect in the data and, consequently, in the resistivity model. A synthetic study was also conducted, seeking to understand what to expect from the resistivity-only inversions in the real data. According to borehole lithological data and previous structural knowledge from the literature, the results from the Maximum Phase Angle approach indicate an important chargeable body that seems to be in good agreement with a sulfide enriched carbonaceous/graphite and altered mafic unities, which are important markers for the gold mineralisation

Theoretical investigation of the 7F1 level splitting in a series of Eu3+ doped oxides matrixes

The point charge electrostatic model (PCEM) and the simple overlap model (SOM) are applied to a series of oxide crystals (Gd2O3, Y2O3, Lu2O3, In2O3 and Sc2O3) and a silicate glass (Al2O3–SiO2) doped with the Eu3+ ion. The SOM factor ρ(2β)k+1 is input as the shielding factor for all B q k expressions, which enters in the calculations of the crystal-field strength parameter, NV. The maximum splitting ΔE of the 7F1 manifold of the Eu3+ ion is then obtained as a function of NV. It has been developed another way to calculate alpha, which is an expansion factor in the ΔE expression. For the glass, as the mean metal-ligating ions distances are larger than for the crystals, NV and ΔE are smaller, as expected. The prediction of the PCEM shows a linear dependence between ΔE and NV, even though the known mismatch in respect to the experimental splitting is kept. In the case of the SOM, two situations have been analyzed: firstly the charge factor varies in order to reproduce the experimental splitting (a phenomenological procedure); secondly the charge factor is the valence of the oxygen ions. The agreement between the experimental results and theoretical predictions for all investigated systems is very satisfactory in respect to both the linearity between ΔE and NV and the ΔE splitting

Spin alignment of leading K∗(892)0K^{*}(892)^{0} mesons in hadronic Z0Z^0 decays

Helicity density matrix elements for inclusive K*(892)^0 mesons from hadronic Z^0 decays have been measured over the full range of K^*0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x_p values above 0.3, with the matrix element rho_00 rising to 0.66 +/- 0.11 for x_p > 0.7. The values of the real part of the off-diagonal element rho_1-1 are negative at large x_p, with a weighted average value of -0.09 +/- 0.03 for x_p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the qq(bar) system from the Z^0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x_p range. The K^*0 fragmentation function has also been measured and the total rate determined to be 0.74 +/- 0.02 +/- 0.02 K*(892)^0 mesons per hadronic Z^0 decay.Helicity density matrix elements for inclusive K*(892)^0 mesons from hadronic Z^0 decays have been measured over the full range of K^*0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x_p values above 0.3, with the matrix element rho_00 rising to 0.66 +/- 0.11 for x_p > 0.7. The values of the real part of the off-diagonal element rho_1-1 are negative at large x_p, with a weighted average value of -0.09 +/- 0.03 for x_p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the qq(bar) system from the Z^0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x_p range. The K^*0 fragmentation function has also been measured and the total rate determined to be 0.74 +/- 0.02 +/- 0.02 K*(892)^0 mesons per hadronic Z^0 decay.Helicity density matrix elements for inclusive K*(892)^0 mesons from hadronic Z^0 decays have been measured over the full range of K^*0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x_p values above 0.3, with the matrix element rho_00 rising to 0.66 +/- 0.11 for x_p > 0.7. The values of the real part of the off-diagonal element rho_1-1 are negative at large x_p, with a weighted average value of -0.09 +/- 0.03 for x_p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the qq(bar) system from the Z^0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x_p range. The K^*0 fragmentation function has also been measured and the total rate determined to be 0.74 +/- 0.02 +/- 0.02 K*(892)^0 mesons per hadronic Z^0 decay.Helicity density matrix elements for inclusive K*(892)^0 mesons from hadronic Z^0 decays have been measured over the full range of K^*0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x_p values above 0.3, with the matrix element rho_00 rising to 0.66 +/- 0.11 for x_p > 0.7. The values of the real part of the off-diagonal element rho_1-1 are negative at large x_p, with a weighted average value of -0.09 +/- 0.03 for x_p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the qq(bar) system from the Z^0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x_p range. The K^*0 fragmentation function has also been measured and the total rate determined to be 0.74 +/- 0.02 +/- 0.02 K*(892)^0 mesons per hadronic Z^0 decay.Helicity density matrix elements for inclusive K ∗ (892) 0 mesons from hadronic Z 0 decays have been measured over the full range of K ∗ 0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x p values above 0.3, with the matrix element ϱ 00 rising to 0.66 ± 0.11 for x p > 0.7. The values of the real part of the off-diagonal element ϱ 1 - 1 are negative at large x p , with a weighted average value of −0.09 ± 0.03 for x p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the q q system from the Z 0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x p range. The K ∗ 0 fragmentation function has also been measured and the total rate determined to be 0.74 ± 0.02 ± 0.02 K ∗ (892) 0 mesons per hadronic Z 0 decay

Dynamic multi-objective optimisation using deep reinforcement learning::benchmark, algorithm and an application to identify vulnerable zones based on water quality

Dynamic multi-objective optimisation problem (DMOP) has brought a great challenge to the reinforcement learning (RL) research area due to its dynamic nature such as objective functions, constraints and problem parameters that may change over time. This study aims to identify the lacking in the existing benchmarks for multi-objective optimisation for the dynamic environment in the RL settings. Hence, a dynamic multi-objective testbed has been created which is a modified version of the conventional deep-sea treasure (DST) hunt testbed. This modified testbed fulfils the changing aspects of the dynamic environment in terms of the characteristics where the changes occur based on time. To the authors’ knowledge, this is the first dynamic multi-objective testbed for RL research, especially for deep reinforcement learning. In addition to that, a generic algorithm is proposed to solve the multi-objective optimisation problem in a dynamic constrained environment that maintains equilibrium by mapping different objectives simultaneously to provide the most compromised solution that closed to the true Pareto front (PF). As a proof of concept, the developed algorithm has been implemented to build an expert system for a real-world scenario using Markov decision process to identify the vulnerable zones based on water quality resilience in São Paulo, Brazil. The outcome of the implementation reveals that the proposed parity-Q deep Q network (PQDQN) algorithm is an efficient way to optimise the decision in a dynamic environment. Moreover, the result shows PQDQN algorithm performs better compared to the other state-of-the-art solutions both in the simulated and the real-world scenario

AVALIAÇÃO DE DANO MECÂNICO EM SEMENTES DE FEIJÃO POR MEIO DE CONDUTIVIDADE ELÉTRICA

RESUMO Este trabalho foi realizado com o intuito de se avaliar danos mecânicos em sementes de feijão ( Phaseolus vulgaris L.) variedade Ouro Negro 1992, por meio de condutividade elétrica da solução contendo as sementes danificadas devido ao choque mecânico controlado, com utilização de três níveis de velocidade de choque. Para se comparar a queda de qualidade devido ao choque mecânico, foram utilizados também o teste-padrão de germinação e a avaliação visual dos danos mecânicos, cujos resultados permitiram concluir que a utilização da condutividade elétrica da solução contendo as sementes pode ser correlacionada com o índice de danos mecânicos podendo, portanto, ser utilizada para avaliar danos mecânicos em sementes