Microstructure and Phase Investigation of Sn-58Bi-xCu Lead-Free Solder After Immersion in Sodium Chloride Solution

The changes in microstructure and phase of tin-bismuth-copper (Sn-58Bi-xCu) were investigated after immersion in 3.5 wt. % sodium chloride (NaCl) at variations of Cu micro-alloying at 0.25, 0.50, 0.75, 1.00 and 1.25 wt. %. The morphological observation revealed that the long crystal grains of the Cu-rich phase were produced as the amount of Cu increased. The phase analysis shows that at 0.5 wt. % Cu additions, the intermetallic compound od Cu6Sn5 began to form and dominate the microstructure. After immersion in NaCl, a porous structure was seen covering the surface of the ternary solder, indicating the formation of a defective corrosion protection layer. The predominance of Cu6Sn5 is believed to boost the galvanic corrosion coupling potential of the ternary solder. As a result, the more electrochemically reactive phase was pushed to be eliminated during immersion in 3.5 wt.% NaCl solution. Thus the black spots were formed. The presence of Cu6Sn5 was seen to be detrimental to the electrochemical performance of Sn-58Bi-xCu.

How to Power the Energy–Water Nexus: Coupling Desalination and Hydrogen Energy Storage in Mini-Grids with Reversible Solid Oxide Cells

Sustainable Development Goals establish the main challenges humankind is called to tackle to assure equal comfort of living worldwide. Among these, the access to affordable renewable energy and clean water are overriding, especially in the context of developing economies. Reversible Solid Oxide Cells (rSOC) are a pivotal technology for their sector-coupling potential. This paper aims at studying the implementation of such a technology in new concept PV-hybrid energy storage mini-grids with close access to seawater. In such assets, rSOCs have a double useful effect: charge/discharge of the bulk energy storage combined with seawater desalination. Based on the outcomes of an experimental proof-of-concept on a single cell operated with salty water, the operation of the novel mini-grid is simulated throughout a solar year. Simulation results identify the fittest mini-grid configuration in order to achieve energy and environmental optimization, hence scoring a renewable penetration of more than 95%, marginal CO2 emissions (13 g/kWh), and almost complete coverage of load demand. Sector-coupling co-production rate (desalinated water versus electricity issued from the rSOC) is 0.29 L/kWh.

Numerical analysis of propeller loading with a coupling RANS and potential approach

In this paper, we present a coupling potential and Reynolds-averaged Navier–Stokes (RANS) approach for the analysis of propeller loading and propulsion performance at self-propulsion condition. There is a presentation of a combination of unsteady RANS method for ship flow with free surface taking into account by volume of fluid method and Lifting Line Model for propeller operating behind ship. An intensified coupling strategy is proposed to simulate the propeller effect in the ship wake. The effective wake is re-examined through the iterations, and there is a presentation of the spatial distribution of propeller forces. Propeller unsteady loading of KCS test case is predicted by flow field from both Full RANS and the Coupling method and compared to experiment results. A circulation-based analysis is made to scrutinize the spatial distribution of propeller loading. The simulation results prove that the coupling method can estimate propeller’s loading and effect on averaged flow field. Ultimately, the coupling method is applied to design an optimal propeller accounting for hull–propeller interaction, which shows its potential for further integrated optimization application.

Progress in Coupling Potential Wave Models and Two-Phase Solvers With the SWENSE Methodology

This paper presents the recent developments of the Spectral Wave Explicit Navier-Stokes Equations (SWENSE) method to extend its range of application to two-phase VOF solvers. The SWENSE method solves the wave-structure interaction problem by coupling potential theory and the Navier-Stokes (NS) equations. It evaluates the incident wave solution by wave models based on potential theory in the entire computational domain, leaving only the perturbation caused by the structure and the influence of the viscosity to be solved with CFD. The method was proven in previous studies to be accurate and efficient for wave-structure interaction problems, but it was derived for single-phase NS solvers only. The present study extends the SWENSE method by proposing a novel formulation which is convenient to implement in two-phase NS solvers. A customized SWENSE solver is developed with the open source CFD package Open-FOAM. An improvement in accuracy and stability is observed in wave simulations compared with conventional two-phase VOF solvers. The horizontal force on a vertical cylinder in regular waves is also calculated. First results show a good agreement with the experiment on the first harmonic component.

ECONOMIC VECTOR OF THE EURASIAN UNION: EVALUATION OF COUPLING POTENTIAL WITH REGIONAL INTEGRATION ASSOCIATIONS OF COUNTRIES

The Eurasian Union plans to reach a new level of economic cooperation, and not be restricted to interact only with the individual member states. For this purpose, the Eurasian Union intends to initiate the establishment of a long-term and stable relationships with major integration associations in the world. The assessment analysis found the economic effects of possible cooperation of the Eurasian Union with megaregional structures and taking into account the applicability in the context of the prospects for the «Big Eurasian Partnership» the project shows that in working through various options for cooperation should be taken into account a variety of factors, ranging from issues of tariff regulation to foreign situations, concerning certain countries, integration associations. Priority for identifying potential partners for cooperation given to economic and trade associations with a high degree of costoriented integration. For assessment of the economic effects of a possible cooperation of the Eurasian Union with megaregional structures was used the gravity model to identify the sensitivity of imports to changes in tariff policy, and an analysis of the competitive advantages of production of the Eurasian Union countries was conducted with competitiveness index.

Intramolecular allosteric communication in dopamine D2 receptor revealed by evolutionary amino acid covariation

The structural basis of allosteric signaling in G protein-coupled receptors (GPCRs) is important in guiding design of therapeutics and understanding phenotypic consequences of genetic variation. The Evolutionary Trace (ET) algorithm previously proved effective in redesigning receptors to mimic the ligand specificities of functionally distinct homologs. We now expand ET to consider mutual information, with validation in GPCR structure and dopamine D2 receptor (D2R) function. The new algorithm, called ET-MIp, identifies evolutionarily relevant patterns of amino acid covariations. The improved predictions of structural proximity and D2R mutagenesis demonstrate that ET-MIp predicts functional interactions between residue pairs, particularly potency and efficacy of activation by dopamine. Remarkably, although most of the residue pairs chosen for mutagenesis are neither in the binding pocket nor in contact with each other, many exhibited functional interactions, implying at-a-distance coupling. The functional interaction between the coupled pairs correlated best with the evolutionary coupling potential derived from dopamine receptor sequences rather than with broader sets of GPCR sequences. These data suggest that the allosteric communication responsible for dopamine responses is resolved by ET-MIp and best discerned within a short evolutionary distance. Most double mutants restored dopamine response to wild-type levels, also suggesting that tight regulation of the response to dopamine drove the coevolution and intramolecular communications between coupled residues. Our approach provides a general tool to identify evolutionary covariation patterns in small sets of close sequence homologs and to translate them into functional linkages between residues.

Improvements in Typhoon Intensity Change Classification by Incorporating an Ocean Coupling Potential Intensity Index into Decision Trees*,+

Tropical cyclone (TC) intensity prediction, especially in the warning time frame of 24–48 h and for the prediction of rapid intensification (RI), remains a major operational challenge. Sea surface temperature (SST) based empirical or theoretical maximum potential intensity (MPI) is the most important predictor in statistical intensity prediction schemes and rules derived by data mining techniques. Since the underlying SSTs during TCs usually cannot be observed well by satellites because of rain contamination and cannot be produced on a timely basis for operational statistical prediction, an ocean coupling potential intensity index (OC_PI), which is calculated based on pre-TC averaged ocean temperatures from the surface down to 100 m, is demonstrated to be important in building the decision tree for the classification of 24-h TC intensity change ΔV24, that is, RI (ΔV24 ≥ 25 kt, where 1 kt = 0.51 m s−1) and non-RI (ΔV24 < 25 kt). Cross validations using 2000–10 data and independent verification using 2011 data are performed. The decision tree with the OC_PI shows a cross-validation accuracy of 83.5% and an independent verification accuracy of 89.6%, which outperforms the decision tree excluding the OC_PI with corresponding accuracies of 83.2% and 83.9%. Specifically for RI classification in independent verification, the former decision tree shows a much higher probability of detection and a lower false alarm ratio than the latter example. This study is of great significance for operational TC RI prediction as pre-TC OC_PI can skillfully reduce the overestimation of storm potential intensity by traditional SST-based MPI, especially for the non-RI TCs.