Full Coupling Research Articles

Influence of steel reinforcement on the performance of an RC structure subjected to a high-velocity large-caliber projectile

The reinforcement setting in reinforced concrete (RC) protective structure should be optimized to resist the impact of high-velocity large-caliber projectiles (LCPs), which is yet to be clearly understood. This study adopts a high-fidelity finite element analysis (FEA) approach to examine the influence of steel reinforcement setting, including the diameter/spacing/strength of reinforcement, the number/spacing/distribution depth of the mesh layer, and the reinforcement ratio, on the performance of RC structure against the large-caliber projectile impact. The FEA approach utilizes an improved dynamic constitutive model of concrete recently proposed by the authors to capture the responses of concrete, i.e., the penetration resistance, cratering, scabbing, and cracking failure, and the *CONSTRAINED_BEAM_IN_SOLID coupling method to consider the bond-slip relation between steel reinforcement and concrete. By simulating the 64 mm-diameter projectile impact tests on the plain concrete (PC) and RC targets, it validates the established FEA approach in contrast to that using the existing concrete models in LS-DYNA, i.e., the Holmquist-Johnson-Cook, Riedel-Thoma-Hiermaier, and Karagozian & Case concrete models, and the full coupling method, i.e., the *CONSTRAINED_LAGRANGE_IN_SOLID. The performance of the RC target struck by a 154 mm-diameter LCP is further numerically studied using the validated FEA approach. Based on more than fifty simulation cases, it derives the optimal reinforcement setting for the engineering design: (i) increasing the mesh layer number should be given priority to increasing the reinforcement ratio; (ii) the optimal rebar diameter and spacing are 1/15 and 1/2 of projectile diameter, respectively; (iii) uniform distribution of reinforcement layer along target thickness is suggested; (iv) normal strength reinforcement is preferred; (v) the practical highest reinforcement ratio is 4% to reduce structural thickness.

Baseline local impedance and changes in local impedance are predictors of electrode tissue coupling in RF-ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Radiofrequency (RF) current remains the most ablation technology in the electrophysiologic laboratory. Durable lesion formation without collateral tissue damage is key for obtaining efficient and safe procedures. RF power, duration and contact force are considered as main determinants of lesion size. Recently published data show that electrode tissue coupling (ETC) is another important parameter of lesion formation. This ex vivo model was created to investigate local impedance changes and lesion size when alternating ETC-levels. Methods RF-lesions were created using a force and local impedance sensing catheter in an ex vivo porcine cardiac model. The experimental setup consisted of a saline-filled container, a dispersive electrode, a heated thermostat and a circulation pump to imitate in vivo conditions. Global impedance was kept at 120 Ohm as well as the temperature at 37°C. RF-lesions were created using identic values of RF duration and contact force. A RF power of 20W, 30W, 40W, and 50W was used. The ETC levels were systematically varied between minor and full coupling. In minor ETC-level, only the distal end of the catheter is in contact with the tissue. In full ETC-level, the whole catheter tip is in contact with the tissue. All parameters (power, temperature, global and local impedance, contact force, ETC, lesion size) were measured constantly during application of RF-current, enabling real-time correlation of RF parameters and lesion size. In case of an audible steam pop, RF application was stopped. Results 8654 measurements of lesion depth and diameter were analyzed after creating 72 lesions. Lesion depth and diameter in full ETC-level were significantly higher compared to minor ETC-level (s. Table 1). Interestingly, lesions in lower power levels (20-30 Watt), but full ETC-level became wider and deeper than lesions in high power levels (40-50 Watts), but minor ETC-level (s. Figure 1). These observations were made despite shorter RF-duration (54.00 ± 13.07 s vs. 47.11 ± 17.57 s, p=0.032) in lesions with full ETC-level due to higher incidence of steam pops (14 vs. 6 steam pops, p = 0.032). Baseline LI and LI-drop were significantly higher in full ETC-level (Figure 2), but no relevant difference was observed in baseline GI. Conclusion Baseline LI and LI changes during ablation provide information about ETC-levels and interaction of the RF ablation catheter with cardiac tissue. ETC-levels, as predicted by LI, had a significantly higher impact on RF lesion size than RF power or RF-duration. Therefore, LI should be monitored during RF ablation for estimating ETC-levels and lesion formation.

Electrode tissue coupling (ETC) influences lesion formation stronger than contact force

Abstract Funding Acknowledgements Type of funding sources: None. Background Several parameters are assumed to influence lesion size in RF ablation. Especially RF power, duration and contact force are considered for optimizing lesion quality and creating durable lesions. Recent data showed a significant influence of electrode-tissue-coupling (ETC) on lesion size and occurrence of steam pops. Therefore, this study aimed to investigate the impact of ETC and contact force on lesion progression in RF ablation. Methods RF-lesions were created using a contact force sensing catheter with the ability of measuring local impredance in an ex vivo porcine cardiac model. The experimental setup consisted of a saline-filled container, a dispersive electrode, a heated thermostat and a circulation pump to imitate in vivo conditions. Global impedance was kept at 120 Ohm as well as the temperature at 37°C. RF power of 20W, 30W, 40W, and 50W was used. The ETC levels (full/minor) and CF-level (1-5g, 10-15g and 20-25g) were systematically varied between minor and full coupling. In minor ETC-level, only the distal end of the catheter is in contact with the tissue. In full ETC-level, the whole catheter tip is in contact with the tissue. All parameters (power, temperature, global and local impedance, contact force, ETC, lesion size) were measured constantly during application of RF-current, enabling real-time correlation of RF parameters and lesion size. In case of an audible steam pop, RF application was stopped. Results 8654 measurements out of 72 lesions were included in analysis. Significant differences in lesion size were observed when ETC-level was differed. Lesion depth was significantly higher in full ETC-level (5.13 ± 0.99 mm vs. 9.45 ± 1.45 mm, p<0.001). No significant difference was seen in lesion diameter and depth by varying CF-level, when lesions were created in full ETC-level (Table 1). These findings are also illustrated in Figure 1. When lesions were analyzed in minor ETC-level only, significant differences were observed, when CF-levels were varied (Table 2). Conclusion ETC is a main predictor of lesion size in RF-ablation. CF also influences lesion depth and diameter. However, significant differences were only observed in minor ETC-levels. Consequently, CF might be a main factor for durable lesions in RF-ablation, but the influence of varied CF decreases when ETC-level is rising.

Local impedance changes are a suitable real time surrogate for lesion formation in RF-ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Radiofrequency current remains one of the most important techniques for catheter ablation. Creating durable lesions is key for sufficient and safe procedures. Several possibilities were tested for estimating the progress of lesion formation. For instance, force-time-integral, ablation index and lesion size index are used to assess quality of RF-application and, therefore, lesion size and durability. Nevertheless, recovered conduction after acute conduction block remains an issue in RF-ablation. The aim of this study was to evaluate local impedance (LI) changes as real time surrogate for lesion formation. Methods RF-lesions were created using an ex vivo porcine cardiac model and a force and local impedance sensing catheter. The experimental setup consisted of a saline-filled container, a dispersive electrode, a heated thermostat and a circulation pump to imitate in vivo conditions. Global impedance was kept at 120 Ohm as well as the temperature at 37°C. RF-lesions were created using identic values of RF duration and contact force. RF power (20W, 30W, 40W, 50W) and level of electrode-tissue-coupling were also systematically varied between minor and full coupling. In minor ETC-level, only the distal end of the catheter is in contact with the tissue. In full ETC-level, the whole catheter tip is in contact with the tissue. All parameters (power, temperature, global and local impedance, contact force, ETC, lesion size) were measured constantly during application of RF-current, enabling real-time correlation of RF parameters and lesion size. In case of an audible steam pop, RF application was stopped. Results Including a total of 8654 measurements into the analysis, maximum diameter and depth were 9.51 ± 1.91 mm and 7.29 ± 2.50 mm in average. Local impedance correlated well with lesion depth (r= 0,78, p<0,001), as well as lesion diameter (r=0,652, p<0,001, Figure 1). After significant declines of LI at the beginning of RF-application, it slowly approximates a minimum. Lesion size on the other hand, rises exponentially in first seconds and gets closer to a maximum after more than 25 seconds. This relationship is illustrated in Figure 2. With decreasing lesion growth at the end of RF-application, LI changes decrease to low level (Figure 3). Conclusion Lesion formation in RF-ablation is not linear during application of RF current. Local impedance changes seem to be a suitable real-time surrogate for assessing changes in lesion size during ablation.

Theoretical Investigation of Localized- and Itinerant Character of 4f Electron in Ce Intermetallics by Means of 3d-4f Resonant Inelastic X-ray Scattering

In order to show characteristic features in core-level spectroscopy, reflecting the localized- or itinerant nature of 4f electrons in Ce intermetallics, 3d x-ray photoemission spectroscopy, 3d x-ray absorption spectroscopy and 3d-4f resonant inelastic x-ray scattering (RIXS) are theoretically investigated for CeIn3 and CeSn3 with the AuCu3-type crystal structure. In this study, considering energy-band effects based on first-principles calculation within local density approximation, we employ an impurity Anderson model with full multiplet coupling. Moreover, in order to make a quantitative discussion, the basis configurations describing electron–hole pair creation are also included in the calculation within the configuration interaction scheme, which have been often neglected as a first approximation in previous studies. By comparing the calculated results for CeIn3 and CeSn3, we find two advantages of 3d-4f RIXS for a quantitative investigation of Ce intermetallics: (i) we can observe directly a binding energy in Kondo singlet formation by choosing proper polarization geometry of incident photons, and (ii) we can investigate an itinerant component related to Kondo singlet formation of Ce intermetallics by adjusting energy and polarization of incident photons.

Discrete differential geometry modeling on the fully coupled vibration of the viscoelastic rod interacting with rigid cylinders

The coupled vibration of flexible rods in contact with rigid cylinders has been observed to generate disruptive noise and significantly decrease the service life. Although the coupling effect of cylindrical rotation with transverse vibration or axial motion of slender rods has been well studied, the full coupling of the three motions remains inadequately understood. To address this issue, we propose an improved discrete differential geometry model with a tri-linear friction method to deliver accurate reproduction of resonant frequencies and vibration responses. Our model features several advances: (i) Viscous forces associated with stretching and bending strain rates are incorporated into the motion equation of the viscoelastic rod, replacing the assumption of quasi-static axial motion; (ii) A tri-linear friction method is introduced to obtain the relative motion between the slender rod and cylinders on the contact zone, thus eliminating errors stemming from pre-prescribed contact regions; (iii) The model fully couples the axial and transverse motion over the entire rod as well as the rotation of cylinders, surpassing the limitation of the coupled rotational-transverse model which only establishes equations of transverse motion on the non-contact zone of the rod. The numerical results indicate that the axial and transverse vibrations of the upper and lower span of the slender rod and the cylindrical rotational vibration are mutually excited, with their resonant frequencies having overlapping sites, which validates the proposed coupling model. Moreover, we are able to capture the phenomenon of contact surface sliding during the coupled vibration, confirm that the sliding limits the vibration amplitude, and determine the nonlinear relationship between the excitation and vibration response. This work provides a theoretical basis for further optimization of composite transmission structures, particularly in terms of suppressing vibration and improving efficiency of power transmission.

Coupled dynamic characteristics of 10 MW semi-submersible offshore wind turbine under typical operation, extreme, and fault conditions

The Technical University of Denmark (DTU) 10 MW wind turbine is selected as the object of this study. The braceless semi-submersible platform for the National Renewable Energy Laboratory 5 MW wind turbine is upscaled to support the DTU 10 MW wind turbine. The servo control system of the 10 MW semi-submersible wind turbine is redesigned. Furthermore, torque control is performed below the rated wind speed to achieve maximum power capture, and the gain scheduling proportional integral (GSPI) control method is performed above the rated wind speed to realize the design of the variable propeller control system. This ensures the safe operation of the floating wind turbine above the rated wind speed. The reliability of the designed servo control system is verified by a full coupling dynamic response analysis with the designed servo control system, aerodynamics, and hydrodynamics under the combined action of wind and waves. The coupled dynamic characteristics of the 10 MW semi-submersible wind turbine under different conditions are analyzed, including operational, extreme, and fault situations. The results show that the servo control system effectively controls the motion response of a 10 MW floating offshore wind turbine (FOWT). Turbulent wind has an obvious excitation effect on the surge and pitch of the FOWT, whereas the heave motion is primarily excited by wave loads. Different fault conditions can cause different motion and structural responses. Furthermore, the tower top bending moment is greatly affected by the imbalance of aerodynamic load, and the surge, pitch motion, tower base bending moment, and mooring tension of the FOWT are affected by different fault conditions to varying degrees. In addition, the heave motion is generally barely affected by the fault conditions.

A multiphysical‐geochemical coupling model for caprock sealing efficiency in CO2 geosequestration

AbstractPrecipitation or dissolution due to geochemical reactions has been observed in the caprocks for CO2 geosequestration. Geochemical reactions modify the caprock sealing efficiency with self‐limiting or self‐enhancement. However, the effect of this modification on the caprock sealing efficiency has not been fully investigated through multiphysical‐geochemical coupling analysis. In this study, a multiphysical‐geochemical coupling model was proposed to analyze caprock sealing efficiency. This coupling model considered the full couplings of caprock deformation, two‐phase flow, CO2 concentration diffusion, geochemical reaction, and CO2 sorption. The two‐phase flow only occurs in the fracture network and the CO2 may partially dissolve into water and diffuse through the concentration difference. The dissolved CO2 has geochemical reactions with some critical minerals, thus altering flow channels. The CO2 in the fracture network diffuses into matrix, causing the matrix swelling. This fully coupling model was validated with a penetration experiment on a cement cube and compared with two other models for CO2 storage plumes. Finally, the effects of geochemical reactions on penetration depth and pore pressure were studied through parametric study. The numerical simulations reveal that the coupling of geochemical reactions and matrix diffusion significantly affect the caprock sealing efficiency. Geochemical reactions occur at a short time after the arrival of CO2 concentration and modify the fracture porosity. The CO2 diffusion into the matrix requires a much longer time and mainly induces matrix swelling. These effects may produce self‐enhancement or self‐limiting depending on the flow rate in the fracture network, thus significantly modifying caprock sealing efficiency.

Numerical analysis method of ship-ice collision-induced vibration of the polar transport vessel based on the full coupling of ship-ice-water-air

As the Arctic Channel continues to be developed, collisions between polar navigation vessels and sea ice are inevitable, which will directly affect structural safety and vibration comfort. However, the numerical analysis method of ship–ice collision-induced vibration is not perfect, and the effect of fluid coupling is not typically considered. In this paper, a simplified numerical analysis method for ship–ice collision-induced vibration is proposed, in which a reliable ice load is obtained by first performing ship–ice–water–air coupled collision calculations, followed by ship–ice–water coupled vibration calculations to obtain the vibration response of the structure. In addition, this paper investigates the full coupling method and the modeling ranges and meshing sizes involved in the analysis ship–ice collision-induced vibration, and the computational efficiencies of the traditional ALE algorithm and S-ALE algorithm are compared. The results indicate that the simplified simulation analysis method and gradient meshing model improve the calculation accuracy and efficiency in ship-ice collision and vibration response analysis. Moreover, the modeling range of the water and air models cannot be less than 6 times the ship width, 2 times the ship length, and 1 times the ship depth, and the S-ALE algorithm saves 47.86% time compared to the ALE algorithm. The research results in this paper can provide a reference for the numerical simulation of ship–ice collision-induced vibration.

PO-03-064 BASELINE LOCAL IMPEDANCE AND CHANGES IN LOCAL IMPEDANCE ARE PREDICTORS OF ELECTRODE TISSUE COUPLING IN RF-ABLATION

Radiofrequency (RF) current remains the most used ablation technology in the EP lab. Durable lesion formation without collateral tissue damage is key for obtaining efficient and safe procedures. RF power, duration and contact force (CF) are considered as main determinants of lesion size. Recently published data show that electrode tissue coupling (ETC) is another important parameter of lesion formation. This ex vivo model was created to investigate local impedance (LI) changes and lesion size when alternating ETC-levels. RF-lesions were created using a CF and LI sensing catheter in an ex vivo porcine cardiac model. The experimental setup consisted of a saline-filled container, a dispersive electrode, a heated thermostat and a circulation pump to imitate in vivo conditions. Global impedance was kept at 120 Ohm as well as the temperature at 37°C. RF-lesions were created using identic values of RF duration and contact force. RF power of 20W, 30W, 40W, and 50W was used. The ETC levels were systematically varied between minor and full coupling. In minor ETC-level, only the distal end of the catheter is in contact with the tissue. In full ETC-level, the whole catheter tip is in contact with the tissue. All parameters (power, temperature, global and local impedance, CF, ETC, lesion size) were measured constantly during RF-application, enabling real-time correlation of all parameters and lesion size. 8654 measurements of lesion depth and diameter were analyzed after creating 72 lesions. Lesion depth and diameter in full ETC-level were significantly higher compared to minor ETC-level (s. Table 1). Interestingly, lesions in lower power levels (20-30 Watt), but full ETC-level became wider and deeper than lesions in high power levels (40-50 Watts), but minor ETC-level (s. Figure 1). These observations were made despite shorter RF-duration (54.00 ± 13.07 s vs. 47.11 ± 17.57 s, p=0.032) in lesions with full ETC-level due to higher incidence of steam pops (14 vs. 6 steam pops, p = 0.032). Baseline LI and LI-drop were significantly higher in full ETC-level (Figure 1), but no relevant difference was observed in baseline GI. Baseline LI and LI changes during ablation provide information about ETC-levels and interaction of the RF ablation catheter with cardiac tissue. ETC-levels, as predicted by LI, had a significantly higher impact on RF lesion size than RF power or RF-duration. Therefore, LI should be monitored during RF ablation for estimating ETC-levels and lesion formation.Tabled 1Table 1. Lesion size and impedance changes in different ETC-levels.Minor ETC (n=36)Full ETC (n=36)p-valueMaximum diameter [mm]8.48 ± 1.6110.54 ± 1.63<0.001Maximum depth [mm]5.13 ± 0.999.45 ± 1.45<0.001Start LI [Ω]236.89 ± 26.42300.67 ± 21.61<0.001Start GI [Ω]150.61 ± 21.61151.33 ± 23.680.893LI-drop [Ω]-53.61-125.53<0.001GI-drop [Ω]-21.33-33.44<0.001 Open table in a new tab

PO-03-066 LOCAL IMPEDANCE CHANGES ARE A SUITABLE REAL TIME SURROGATE FOR LESION FORMATION IN RF-ABLATION

Radiofrequency current remains one of the most important techniques for catheter ablation. Creating durable lesions is key for sufficient and safe procedures. Several possibilities were tested for estimating the progress of lesion formation. For instance, force-time-integral, ablation index and lesion size index are used to assess quality of RF-application and, therefore, lesion size and durability. Nevertheless, recovered conduction after acute conduction block remains an issue in RF-ablation. The aim of this study was to evaluate local impedance (LI) changes as real time surrogate for lesion formation. RF-lesions were created using an ex vivo porcine cardiac model and a contact force and LI sensing catheter. The experimental setup consisted of a saline-filled container, a dispersive electrode, a heated thermostat and a circulation pump to imitate in vivo conditions. Global impedance was kept at 120 Ohm as well as the temperature at 37°C. RF-lesions were created using identic values of RF duration and contact force. RF power (20W, 30W, 40W, 50W) and level of electrode-tissue-coupling were also systematically varied between minor and full coupling. All parameters (power, temperature, global and local impedance, contact force, ETC, lesion size) were measured constantly during 60 seconds of RF-application, enabling real-time correlation of RF parameters and lesion size. In case of an audible steam pop, RF application was stopped. Including a total of 8654 measurements into the analysis, maximum diameter and depth were 9.51 ± 1.91 mm and 7.29 ± 2.50 mm in average. LI correlated well with lesion depth (r= 0,78, p<0,001), as well as lesion diameter (r=0,652, p<0,001). After significant declines of LI at the beginning of RF-application, it slowly approximates a minimum. Lesion size on the other hand, rises exponentially in first seconds and gets closer to a maximum after more than 25 seconds. With decreasing lesion growth at the end of RF-application, LI changes decrease to low level (Figure 1). Lesion formation in RF-ablation is not linear during application of RF current. Local impedance changes seem to be a suitable real-time surrogate for assessing changes in lesion size during ablation.

An improved reduced order model for bladed disks including multistage aeroelastic and structural coupling

To assess the influence of mistuning on the vibration amplitudes of turbomachinery rotors, reduced order models (ROMs) are widely used. A variety of methods are available for single-stage configurations and mostly aeroelastic effects can be taken into account. More recent research focusses on extending these methods to include multiple stages. However, due to the significantly increased computational effort of the aeroelastic simulations when adding more stages to the models, these ROMs are rarely applied with the inclusion of multistage aeroelastic effects. It is therefore desirable to develop reduction methods which minimize the number of these simulations to reduce the computational cost and thereby enable analyses of rotors with multiple stages including aeroelastic effects. In this paper, a cyclic Craig-Bampton reduction method with an a priori interface reduction for multistage rotors is extended with an additional a posteriori interface reduction to reduce the number of aeroelastic simulations necessary for a given accuracy level of the ROM. The interface degrees of freedom between stages are reduced using a modified version of Characteristic Constraint Modes, to yield a more efficient representation of their displacements while retaining their monoharmonic nature. The method is applied to a two-stage axial compressor with full aeroelastic coupling between the stages and its reduced computational effort is demonstrated. Additionally, two sorting methods for the degrees of freedom (DOFs) of the ROM are compared.

Numerical simulation of a fire resistance test and prediction of the flue gas leakage using CFD/FEM coupling

PurposeIn fire resistance tests (FRTs) of building materials, a crucial criterion to pass the test procedure is to avoid the leakage of the hot flue gases caused by gaps and cracks occurring due to the thermal exposure. The present study's aim is to calculate the deformation of a steel door, which is embedded within a wall made of bricks, and qualitatively determine the flue gas leakage.Design/methodology/approachA computational fluid dynamics/finite element method (CFD/FEM) coupling was introduced representing an intermediate approach between a one-way and a full two-way coupling methodology, leading to a simplified two-way coupling (STWC). In contrast to a full two way-coupling, the heat transfer through the steel door was simulated based on a one-way approach. Subsequently, the predicted temperatures at the door from the one-way simulation were used in the following CFD/FEM simulation, where the fluid flow inside and outside the furnace as well as the deformation of the door were calculated simultaneously.FindingsThe simulation showed large gaps and flue gas leakage above the door lock and at the upper edge of the door, which was in close accordance to the experiment. Furthermore, it was found that STWC predicted similar deformations compared to the one-way coupling.Originality/valueSince two-way coupling approaches for fluid/structure interaction in fire research are computationally demanding, the number of studies is low. Only a few are dealing with the flue gas exit from rooms due to destruction of solid components. Thus, the present study is the first two-way approach dealing with flue gas leakage due to gap formation.

Porous Media Model of Reservoir considering Seepage Stress Coupling and Seepage Field Analysis

In the process of reservoir exploitation, the range of rock stress field changes is much larger than the reservoir area where the seepage occurs; so the amount of calculation of the existing seepage stress full coupling method is often very huge. Based on the theory of seepage mechanics and rock mechanics, a coupling analysis model of reservoir multiphase seepage and stress is established, and a numerical solution is established by using finite element and finite difference methods. The evolution law of the seepage field and stress field and the change of rock mechanics parameters can be studied, with emphasis on the readjustment of rock stress distribution and its deformation characteristics under the influence of the seepage field. At the same time, to improve the calculation efficiency of numerical simulation, considering the difference between the seepage calculation area and stress calculation area, the finite element method is improved. The percolation area of the reservoir is calculated with a fine grid to obtain a more accurate distribution of underground fluid. The coarse grid is used to calculate the stress calculation area and to reduce the calculation time. The mechanical equilibrium equation in the fully coupled theory is discretized on the coarse grid by the finite element method. The mass conservation equation is discretized on the fine grid by the finite volume method. The numerical simulation of Terzaghi’s one-dimensional consolidation problem and Mandel’s two-dimensional consolidation problem shows that the calculation results of this method are in good agreement with the analytical solution. Through the numerical calculation of a two-dimensional single-phase flow single well production problem and a three-dimensional two-phase flow five-point well pattern production problem, the influence of the seepage stress coupling effect in reservoir numerical simulation is analyzed.

High cost of slow energy transitions for emerging countries: On the case of Egypt's pathway options

The Paris Agreement targets to halt the progression of climate change necessitate global cooperation and renewable energy uptake in developed and developing countries at similar rates. This study explores the energy transition pathway options for Egypt across the power, heat, transport, and desalination sectors as a representative case study for other emerging sunbelt economies. The LUT Energy System Transition Model has been used to investigate the feasibility of six scenarios, including four variations of best policy, delayed policy, and current policy scenarios. The least-cost solution, achieving 100% renewable energy and zero CO2 emissions by 2050, is dominated by solar photovoltaics at 90% of the total primary energy demand. Key transition enablers are the excellent and low-cost solar resources, energy storage, and Power-to-X technologies allowing high electrification and full sector coupling. The results reveal that the current and delayed policy scenarios are the most expensive pathways, highlighting the value of leapfrogging into a fully renewable system. Such a transition would require policy reforms that balance investment risks in emerging economies and enable its financial mobilisation. The structural results of this study provide a reliable guide for energy transition planning in Egypt as well as other emerging sunbelt economies.

Postural and Gestural Synchronization, Sequential Imitation, and Mirroring Predict Perceived Coupling of Dancing Dyads

Body movement is a primary nonverbal communication channel in humans. Coordinated social behaviors, such as dancing together, encourage multifarious rhythmic and interpersonally coupled movements from which observers can extract socially and contextually relevant information. The investigation of relations between visual social perception and kinematic motor coupling is important for social cognition. Perceived coupling of dyads spontaneously dancing to pop music has been shown to be highly driven by the degree of frontal orientation between dancers. The perceptual salience of other aspects, including postural congruence, movement frequencies, time-delayed relations, and horizontal mirroring remains, however, uncertain. In a motion capture study, 90 participant dyads moved freely to 16 musical excerpts from eight musical genres, while their movements were recorded using optical motion capture. A total from 128 recordings from 8 dyads maximally facing each other were selected to generate silent 8-s animations. Three kinematic features describing simultaneous and sequential full body coupling were extracted from the dyads. In an online experiment, the animations were presented to 432 observers, who were asked to rate perceived similarity and interaction between dancers. We found dyadic kinematic coupling estimates to be higher than those obtained from surrogate estimates, providing evidence for a social dimension of entrainment in dance. Further, we observed links between perceived similarity and coupling of both slower simultaneous horizontal gestures and posture bounding volumes. Perceived interaction, on the other hand, was more related to coupling of faster simultaneous gestures and to sequential coupling. Also, dyads who were perceived as more coupled tended to mirror their pair's movements.

Numerical study of magneto-optical binding between two dipolar particles under illumination by two counter-propagating waves

Introduction: The formation of a stable magneto plasmonic dimer with THz resonances is theoretically studied for the principal directions of the system. Unlike a recent report, our work provides a complete description of the full photonic coupling for arbitrary magnetic fields as, for instance, unbalanced particle spins.Methods: As an illustration, we consider two small, n-doped InSb nanoparticles under illumination by two counter-propagating plane waves.Results: Remarkably, when an external magnetic field exists, the symmetry in the system is broken, and a resonant radiation pressure for the dimer appears. Similarly, tunable inter-particle forces and spins are exerted on the non-reciprocal dimer. The system is also characterized when the magnetic field is absent. Moreover, we show how the mechanical observables truly characterize the dimer since their resonance dependency contains detailed information about the system.Discussion: Unlike far-field observables like absorption, mechanical magnitudes depend on the system's near-field. In addition, the nature of the particle spins is originally explained by the energy flow's behavior around the dimer. This work constitutes a generalization of any previous approach to optical binding between small nanoparticles. It paves the way for fully controlling optical matter and nano factory designs based on surface plasmon polaritons.

The role of phase transition by inception and surface reactions for the synthesis of silicon nanoparticles in a hot-wall reactor – Simulation and experiment

A novel Eulerian particle model tailored for the application in computational fluid dynamics (CFD) is presented. The model is based on a bivariate moment method and features a full coupling with the gas-phase by kinetic formulations for inception, and activated and non-activated surface reactions. A new formulation for the particle composition accounts for the volatile content and its emission. The model is applied in the context of silicon nanopowder synthesis from monosilane, where a validation is performed with a well-established hot-wall reactor experiment from the literature. It is characterized by high precursor concentrations at moderate heating temperature of 853 K. Further, a new experiment was conducted for the comparison with the new model approach in a three-dimensional, transient simulation. The semi-industrial hot wall reactor features an unsteady complex flow field with buoyancy driven recirculation. The simulations enable new insights into the unsteady flow, mixing and nanoparticle formation process and contribute to their understanding. For the validation, residence-time dependent data for the precursor concentration, the primary particle size, and the particle number concentration are compared with results of the simulation at different stages. A comparison with the results of stochastic methods serves as further benchmark for the presented model. An excellent agreement with the experimental data is obtained, if essential growth mechanisms are considered. For the semi-industrial hot-wall reactor experiment, the BET surface and particle diameter, as well and the precursor consumption, are compared to the results of the new model and to a description with inception, coagulation, and sintering only. Due to the absence of crucial activated and non-activated surface reactions, the latter model predicts values that deviate more than one order of magnitude from the experimental data, while the new model shows an overall good agreement.

High-entropy P2/O3 biphasic cathode materials for wide-temperature rechargeable sodium-ion batteries

Layered sodium manganese-based oxides are highly attractive cathode materials for sodium-ion batteries but suffer from limited initial coulombic efficiency (ICE) and poor structural stability. Herein, a high-entropy biphasic Na0.7Mn0.4Ni0.3Cu0.1Fe0.1Ti0.1O1.95F0.1 cathode material is reported to exhibit remarkable ICE, rate capability and cyclability. In-situ structural analysis during the preparation of cathode reveals tunable P2/O3 ratios by changing the sintering temperature. The synthesized high-entropy oxide with a P2/O3 ratio of 23:77 (wt%) delivers a high ICE of 97.6%, a considerable discharge capacity of 86.7 mAh g−1 at current density of 800 mA g−1, and respectable capacity retention in a wide temperature range from -40 to 50 °C. Additionally, full cell coupling Na0.7Mn0.4Ni0.3Cu0.1Fe0.1Ti0.1O1.95F0.1 and hard carbon exhibits an energy density of 268.3 Wh kg−1 at power density of 1172 W Kg−1 based on the mass of cathode. Combined experimental and computational investigations suggest that the as-prepared Na0.7Mn0.4Ni0.3Cu0.1Fe0.1Ti0.1O1.95F0.1 cathode favors reversible structural evolution, fast Na+ diffusion kinetics, and low energy barriers due to the unique P2/O3 biphasic structure and high-entropy effect. This study brings an in-depth insight into the design and preparation of high-entropy P2/O3 biphasic cathode to build advanced sodium-ion batteries.

Melamine Foam-Derived Carbon Scaffold for Dendrite-Free and Stable Zinc Metal Anode

Aqueous Zn-ion batteries (AZIBs) are one of the most promising large-scale energy storage devices due to the excellent characteristics of zinc metal anode, including high theoretical capacity, high safety and low cost. Nevertheless, the large-scale applications of AZIBs are mainly limited by uncontrollable Zn deposition and notorious Zn dendritic growth, resulting in low plating/stripping coulombic efficiency and unsatisfactory cyclic stability. To address these issues, herein, a carbon foam (CF) was fabricated via melamine-foam carbonization as a scaffold for a dendrite-free and stable Zn anode. Results showed that the abundant zincophilicity functional groups and conductive three-dimensional network of this carbon foam could effectively regulate Zn deposition and alleviate the Zn anode's volume expansion during cycling. Consequently, the symmetric cell with CF@Zn electrode exhibited lower voltage hysteresis (32.4 mV) and longer cycling performance (750 h) than the pure Zn symmetric cell at 1 mA cm-2 and 1 mAh cm-2. Furthermore, the full battery coupling CF@Zn anode with MnO2 cathode can exhibit a higher initial capacity and better cyclic performance than the one with the bare Zn anode. This work brings a new idea for the design of three-dimensional (3D) current collectors for stable zinc metal anode toward high-performance AZIBs.