Coupling Conditions Research Articles

Comparison of pressure-based flame describing functions measured in an annular combustor under self-sustained oscillations and in an externally modulated linear combustor

One important aspect in the analysis of combustion instabilities in multiple-injector annular systems is that of representing such oscillations with a linear array of injectors. This issue is considered in the present work by comparing flame dynamics in a self-sustained oscillations situation in the annular configuration MICCA-Spray, with experiments carried out in TACC-Spray, a rectangular combustor equipped with five injectors externally modulated by driver units. In the annular system, the coupling mode is azimuthal, and in the linear array, the flames are submitted to a transverse acoustic field. An original method is used to change the limit-cycle pressure oscillations amplitude in the annular system and favor a standing mode with a well-defined nodal line position. It consists in using different arrangements of two types of injectors, leading to various azimuthal staging patterns. The range of pressure oscillation amplitudes is swept in TACC-Spray by changing the external acoustic forcing level. It is thus possible to compare the flame dynamics in forced and self-sustained situations using these two experimental facilities. This is done by examining flame describing functions (FDFs) based on downstream pressure fluctuations measured in the two configurations for different pressure oscillation amplitudes. The trends observed in the two systems are in good agreement, and there is a reasonably good match between the values of the gains and phases determined in the two configurations. The pressure-based FDFs are determined for flames located at different positions with respect to the acoustic mode. It is found that the transverse or azimuthal velocity component has only a weak influence on the pressure-based FDF, the strongest impact being observed in the neighborhood of the velocity antinode. This study demonstrates the ability of a linear-array setup modulated by a transverse mode to reproduce conditions of azimuthal coupling leading to self-sustained limit cycles in an annular combustor.

C3-Chlorination of C2-substituted benzo[b]thiophene derivatives in the presence of sodium hypochlorite.

Benzo[b]thiophene rings are common synthons for the development of novel drugs and materials, and thus, the discovery of facile ways for their functionalization is of value. In this work, a new method for the C3-chlorination of C2-substituted benzothiophene derivatives is described. The chlorine source is sodium hypochlorite pentahydrate (NaOCl·5H2O), and optimal transformations occur in aqueous acetonitrile at 65-75 °C to provide the corresponding C3-halogenated products in variable yields (30-65%). The reaction occurs in the presence of vinyl and alkyl groups, while the presence of alcohols leads to competing oxidation reactions at the heterobenzylic position. The presence of a carbonyl group at the C2-position inhibited the halogenation reaction, while the use of benzofuran led to a highly exothermic reaction, presumably via the formation of a peroxide intermediate. Reactions carried out at lower temperatures led to side reactions associated with competing oxidative processes. To gain a better understanding of the mechanism of the reaction, DFT calculations were carried out, where the heteroatom enables the formation of a hypochlorous acidium ion that serves to generate a C2-C3 chloronium ion intermediate in a step-wise manner, which in turn leads to the formation of an S-stabilized C2-carbocation that undergoes re-aromatization to the corresponding C3-chlorinated products. To probe potential synthetic applications, a model C3-chloro derivative was coupled with phenylboronic acid using standard Suzuki-Miyaura coupling conditions.

Design of Constant-Voltage and Constant-Current Output Modes of Double-Sided LCC Inductive Power Transfer System for Variable Coupling Conditions

Design of Constant-Voltage and Constant-Current Output Modes of Double-Sided LCC Inductive Power Transfer System for Variable Coupling Conditions

On the possibility of mode coupling for low frequency electromagnetic waves in plasmas with anisotropy of temperature

We study the dispersion relation for low frequency electromagnetic waves propagating along the ambient magnetic field and investigate the possibility of occurrence of coupling between waves in the ion cyclotron branch and waves in the whistler branch. The results obtained show that the coupling may occur in the case of conditions leading to the ion cyclotron instability, for sufficiently high value of the ratio between perpendicular and parallel ion temperature, and does not occur in the case of conditions leading to the ion firehose instability. The results also show that the decrease in the value of the plasma beta may lead to the disappearance of the mode coupling conditions. Regarding the effect of the electron population, it is shown that the change in the shape of the electron velocity distribution, from Maxwellian to bi-Kappa form, does not change the results obtained, as long as the electron temperatures are isotropic, but the increase in anisotropy in the electron temperatures may lead to the disappearance of the coupling between the different waves. The consequences of the frequency dependency of the mode coupling conditions are discussed considering wave propagation in an inhomogeneous medium, leading to the conclusion that the energy of a packet of waves of a given mode can be absorbed or mode converted over an extended region of space. These findings can be of relevance for the analysis and understanding of processes related to the conversion between ion cyclotron waves and whistler waves.

A Novel Magnetic Coupler with PQI Cores for Wireless Power Transfer

The magnetic coupler is a key component of the wireless power transfer (WPT) system, which greatly affects the performance of the WPT. This paper proposes a novel magnetic coupler with ferrite PQI cores for the WPT of small drones, which can enhance the magnetic coupling and improve power transfer efficiency. This magnetic coupler includes the transmitting (TX) side and receiving (RX) side. The TX side is made of a helical coil and a ferrite PQ core; and the RX side is made of a helical coil and a ferrite I core plate. Finite element simulations are used to investigate the performance of the proposed magnetic coupler with PQI cores, and compare it with a conventional planar magnetic coupler with two I core plates. In addition, an experimental platform is built to prove the validity of the proposed magnetic coupler with PQI cores. The results show that the coupling coefficient can reach 0.97, and it can exceed 0.446 even under the worst coupling conditions. Meanwhile, power transfer efficiency increases by 10.3% using the magnetic coupler with PQI cores.

Synthesis of unsymmetrical 2,3,7,8-tetrabromo meso-5,10,11,16-tetraaryl- triphyrin(2.1.1) and its use in the synthesis of sterically crowded 2,3,5,7,8,10,11,16-octaarylated triphyrin(2.1.1)s.

Triphyrin(2.1.1) is a 14π aromatic contracted congener of an 18π aromatic porphyrin(1.1.1.1). An unsymmetrical 2,3,7,8-tetrabromo meso-tetraaryl triphyrin(2.1.1) containing four bromides at the β-pyrrole carbons of two out of three pyrrole rings of the triphyrin core was synthesized for the first time in 90% yield by treating meso-tetraaryl triphyrin(2.1.1) with five equivalents of N-bromosuccinimide in 1,2-dichloroethane (DCE) under reflux for 8 h. The X-ray structure revealed that the triphyrin(2.1.1) macrocycle was significantly distorted in 2,3,7,8-tetrabromo meso-tetraaryl triphyrin compared to planar meso-tetraaryl triphyrin. A series of novel sterically crowded 2,3,5,7,8,10,11,16-octaaryl triphyrin(2.1.1)s were synthesized by coupling 2,3,7,8-tetrabromo meso-tetraaryl triphyrin with six different aryl boronic acids under Suzuki-Miyaura coupling conditions. NMR, absorption, electrochemical and theoretical studies revealed that the structure and electronic properties were drastically altered in the 2,3,5,7,8,10,11,16-octaaryl triphyrin(2.1.1) series due to the presence of four additional aryl groups at the β-pyrrole carbons which caused steric crowding at the periphery of the triphyrin core resulting in a decrease in effective π-conjugation in the triphyrin(2.1.1)s.

Insights into the mechanical stability of tetrahydrofuran hydrates from experimental, machine learning, and molecular dynamics perspectives.

Natural gas hydrates (NGHs) hold immense potential as a future energy resource and for sustainable applications such as gas capture and storage. Due to the challenging formation conditions, however, their mechanical properties remain poorly understood. Herein, the mechanical characteristics of tetrahydrofuran (THF) hydrates, a proxy for methane hydrates, were investigated at different ice contents, strain rates, and temperatures using uniaxial compressive experiments. The results unveil a distinct behavior in the peak strength of THF hydrates with a varying ice content, strain rate and temperature, exhibiting an increase as the strain rate and temperature decrease, in contrast to the peak strength-strain rate relationship observed in polycrystalline ice. Based on the experimental data, four machine learning (ML) models including extreme gradient boosting (XGboost), multilayer perceptron (MLP), gradient boosting decision tree (GBDT) and decision tree (DT) were developed to predict the peak strength. The XGboost model demonstrates superior predictive performance, emphasizing the significant influence of ice content and temperature on the peak strength of hydrates. Furthermore, molecular dynamics (MD) simulations were employed to gain insights into the dissociation and formation processes of clathrate cages, as well as phase transitions and amorphization occurring at grain boundaries (GBs) involving diverse unconventional clathrate cages, including 51265, 4151062, 4151064, 425861 and 425862, with 425861 and 425862 cages being predominant. This study enhances our understanding of the mechanical properties and deformation mechanisms of hydrates and provides a ML-based predictive framework for estimating the compressive strength of hydrates under diverse coupling conditions. The findings have significant implications for stability assessments of NGHs and the exploitation of NGH resources.

Investigation of Time-Varying Backlash of Spur Gears in Thermoelastic Coupling Conditions

Investigation of Time-Varying Backlash of Spur Gears in Thermoelastic Coupling Conditions

Vibration damping by periodic additive acoustic black holes

Embedded acoustic black holes (ABHs) have demonstrated significant efficiency in vibration mitigation. However, their practical application is limited due to their inherent low strength. To address this issue, this paper introduces an alternative approach of additive ABHs, which are periodically mounted on the host structure to simultaneously enhance structural rigidity and damping effects. The Gaussian expansion method (GEM) is employed to model the ABH beam and base beam within the framework of Timoshenko beam theory. The coupling between the two substructures is achieved using the nullspace method (NSM) based on the interface coupling condition. Additionally, the wave and Rayleigh–Ritz method (WRRM) is utilized to handle the Bloch-Floquet periodic boundary conditions. The complex dispersion curves are obtained using the k(ω) method, where the imaginary part represents the attenuating waves in space. The accuracy of the proposed model is validated against finite element simulations for the unit cell modes and dispersion curves. The results indicate that local resonance dominates the behavior, overshadowing the Bragg scattering effect. Furthermore, the inclusion of a damping layer results in a strong damping effect across a wide frequency band. Parametric studies reveal that larger lattice constant and increased uniform portion thickness of the ABH contribute to better damping performance, albeit with an associated increase in the added mass of the ABH component. Finally, the damping capability of finite periodic beams with 5 cells is investigated, assessing modal loss factor (MLF), transmissibility, and forced vibration shapes. The findings demonstrate that the proposed additive ABH approach opens up new possibilities for engineering applications.

Simulation of Plastic Deformation Failure of Tillage Tools Based on the Smoothed Particle Hydrodynamics Method

The problems of large deformations, failures, and fractures that agricultural tillage tools may encounter during the cultivation process has long been a concern in the field of agricultural machinery design and manufacturing. It is important to establish a more accurate numerical model to effectively predict tools’ plastic deformation failures and ductile fracture failures. This research develops a numerical model for predicting the plastic deformation failure and ductile fracture failure of agricultural tillage tools using the smoothed particle hydrodynamics (SPH) method and the Johnson–Cook constitutive model. The model uses the Drucker–Prager criterion to describe the elastic–plastic constitutive behavior of the soil, the von Mises criterion to describe the Johnson–Cook constitutive model of the tool, and the coupling condition with the Lennard-Jones repulsive force to describe the interaction between the tool and soil. The numerical results show that the proposed model can effectively simulate the interaction between the tool and soil, as well as the tool’s plastic deformation failure and ductile fracture failure during the agricultural cultivation process. It can also predict the variation trend of the cutting force of the tool. This helps to provide a new approach for the numerical simulation of such problems.

Thermal transport mechanism of 4H–SiC/SiO2 heterostructures: a molecular dynamics study

Silicon carbide (SiC) is widely used in high-frequency, high-speed, and high-power applications such as power electronics, rail transportation, new energy vehicles, and aerospace. However, the thermal properties of the SiC/SiO2 interface, which is commonly found in SiC-based devices, are not yet fully understood. This study aims to investigate the influence of temperature and interface coupling strength on the interface thermal resistance (ITR) of 4H-SiC/SiO2 using non-equilibrium molecular dynamics simulations. Both crystalline and amorphous SiO2, as well as two interface contact modes (Si-terminated and C-terminated), have also been considered. The results reveal that the ITR of 4H-SiC/SiO2 is significantly affected by the interface coupling strength and contact modes. Under strong interface coupling conditions, the ITR for Si-terminated and C-terminated contacts modes of 4H-SiC/SiO2 interfaces are 8.077 × 10−10 m2KW−1 and 6.835 × 10−10 m2KW−1, respectively. However, under weak interface coupling conditions, these values increase to 10.142 × 10−10 m2KW−1 and 7.785 × 10−10 m2KW−1, respectively. Regardless of whether SiO2 is crystalline or amorphous, the ITR of the 4H-SiC/SiO2 interface exhibits a similar trend with increasing temperature (from 300 to 700 K). Additionally, the ITR of the amorphous SiO2 interface is smaller than that of the crystalline SiO2 interface under both strong and weak coupling conditions. To gain insights into the heat transport mechanism, the phonon density of states was analyzed to examine the phonon spectral characteristics under varying coupling strengths. These findings have implications for enhancing the thermal management and heat dissipation of SiC devices, providing a framework for controlling interface phonon scattering, and informing the thermal design of nanodevices.

Compact polarization beam splitter based on metal-capped thin-film LiNbO3-on-insulator plasmonic waveguide

A compact polarization beam splitter based on a triple-waveguide plasmonic directional coupler is proposed and modeled. The directional coupler consists of two usual lithium-niobate-on-insulator (LNOI) ridge waveguides and a metal-capped plasmonic LNOI waveguide located between them. It utilizes stronger polarization dependence of modal birefringence of a plasmonic waveguide. By appropriately designing the plasmonic waveguide geometry, the TM component wave meets the resonant coupling condition and outputs at cross port. Instead, the TE component wave does not meet the resonant coupling condition, cannot be resonant in the triple-waveguide directional coupler and outputs at through port directly. Excellent performance is expected for an optimal device. First, the device shows an ultra-high polarization extinction ratio(PER) of 28.3 dB and an ultra-low insertion loss(IL) of 0.06 dB for the TE-polarized wave, and of 31.7 dB and of 0.31 dB in order for the TM-polarized wave. Second, the working bandwidth with PER > 25 dB and IL < 0.08 dB is 100 nm (1500–1600 nm) for the TE-polarized wave, and that with PER > 20 dB and IL < 0.4 dB is 30 nm (1534–1564 nm) for the TM-polarized wave. Third, the device has a compact structure of 33 μm in length and exhibits definite fabrication tolerance. Overall, the proposed device exhibits ultra-high PER and ultra-low IL, and has a compact size suitable for on-chip use. A comparison shows that present device exhibits advantage in IL and/or size over that based on other LNOI structures or the SOI platform.

Mitigation of Galvanic Corrosion in CFRP-Metal Couples through Addressing the Carbon Surface

Carbon-based reinforcements are widely used in composite materials for a wide range of applications including wind energy and transportation. In the later, the carbon-fiber reinforced polymers (CFRP) components are often joined together with metallic parts creating conditions for galvanic corrosion. Therefore, a deeper understanding of the electrochemical processes occurring at the carbon surfaces is crucial for developing new approaches for the corrosion protection of multi-material assemblies.In the present work, the electrochemical performance of different types of carbons, namely HOPG (Highly Ordered Pyrolytic Graphite) glassy carbon (GC), and CFRP, have been investigated in neutral NaCl solutions under cathodic polarization. At the potentials relevant to galvanic coupling to metals the CFRP surface is the most electrochemically active of the studied carbon surfaces. The ranking of the studied surfaces in terms of supporting the oxygen reduction reaction was established as follows: CFRP > GC > HOPG. It was found that the observed differences in the electrochemical responses of these materials to ORR are correlated with the proportions of edge sites present on each carbon surface [1].Under galvanic coupling conditions in multi-material structures composed of CFRP and Al alloys or Zn, significant degradation of the composite surface occurs at the carbon/electrolyte interface and due to an attack on the epoxy of the matrix phase most probably resulting from nucleophilic attack by hydroxyl and perhydroxyl ions, formed as a result of the oxygen reduction reaction on carbon fiber. The obtained results demonstrate the intense electrochemical activity of CFRP even when slightly polarized cathodically with a concomitant sharp increase in the pH above its surface. Contrary to expectations, exposure of CFRP to degradative high pH media before galvanic coupling did not provoke accelerated galvanic corrosion of the coupled metal under bulk electrolyte immersion conditions [2].The use of the corrosion inhibition approach to suppress the degradation of CFRP and reduce its cathodic activity in the galvanic couples was also demonstrated. It was found that the presence of sodium dodecyl sulphate (SDS) in the electrolyte offers a clear inhibition effect. From the results, it is concluded that SDS interacts with CFRP surface resulting in the formation of a persistent adsorbed layer. Surface analysis by scanning electron microscopy confirms mitigation of the CFRP composite degradation under impressed cathodic polarization in the presence of SDS or after prior exposure to SDS-containing solution [3].[1] S.U. Ofoegbu, M.G.S. Ferreira, H.I.S.Nogueira, M.L. Zheludkevich, Comparison of the Electrochemical Response of Carbon-Fiber-Reinforced Plastic (CFRP), Glassy Carbon, and Highly Ordered Pyrolytic Graphite (HOPG) in Near-Neutral Aqueous Chloride Media, C, 9 (2023) 7.[2] S.U. Ofoegbu, M.C. Quevedo, A.C. Bastos, M.G.S. Ferreira, M.L. Zheludkevich, Electrochemical characterization and degradation of carbon fibre reinforced polymer in quiescent near neutral chloride media, npj Materials Degradation, 6 (2022) 49.[3] S.U. Ofoegbu, K. Yasakau, S. Kallip, H.I.S.Nogueira, M.G.S. Ferreira, M.L. Zheludkevich, Modification of carbon fibre reinforced polymer (CFRP) surface with sodium dodecyl sulphate for mitigation of cathodic activity, Applied Surface Science, 478 (2019) 924-936.

Energy Evolution Law of Sandstone Material during Post-Peak Cyclic Loading and Unloading under Hydraulic Coupling

The sustainability of rock engineering is an emerging trend in future development, as society increasingly recognizes the importance of environmental conservation and responsible resource utilization. In this context, the field of rock engineering is undergoing a paradigm shift toward more sustainable practices. A significant aspect of this shift is the investigation of energy evolution laws specific to rocks, which assumes paramount importance in ensuring the sustainable utilization of damaged rock roadways. To investigate the impact of confining pressure and pore pressure on the energy evolution characteristics of rock beyond the peak, post-peak cyclic loading and unloading tests were conducted on sandstone specimens under hydraulic coupling conditions using the MTS815 rock mechanical test system. The study encompassed three sets of confining pressures, namely, 10 MPa, 20 MPa, and 30 MPa. Different levels of pore pressure were applied within each confining pressure group. For the 10 MPa confining pressure, the pore pressure values were set at 2 MPa, 4 MPa, 6 MPa, and 8 MPa. Similarly, for the 20 MPa and 30 MPa confining pressures, the corresponding pore pressure values were 2 MPa, 6 MPa, 10 MPa, 14 MPa, 18 MPa, and 22 MPa. The experimental findings indicate that as the confining pressure increases, both the maximum and residual elastic energy densities of the rock gradually increase. The rise in confining pressure impedes the release of elastic energy. Moreover, with increasing confining pressure, the rate of increase in the maximum dissipated energy density diminishes, highlighting the inhibitory effect of confining pressure on energy dissipation and release within the rock. Pore pressure, on the other hand, disrupts the load-bearing structure of the rock and reduces its energy storage capacity. Under a constant confining pressure, for a fixed number of cycles (axial strain), the total input energy density, elastic energy density, and dissipation energy density exhibit a negative correlation with pore pressure. With an increase in the number of cycles (axial strain), the proportion of elastic energy initially rises but subsequently declines, while the proportion of dissipated energy follows the opposite trend. Furthermore, as the confining pressure increases, the peak proportion of elastic energy also tends to increase. This indicates that higher confining pressures promote energy accumulation after rock failure, enhancing the rock’s ability to store elastic energy.

A Platform for the Liebeskind-Srogl Coupling of Heteroaromatic Thioethers for Medicinal-Chemistry-Relevant Transformations.

General and robust conditions for the Liebeskind-Srogl coupling were developed and used in functionalization of medicinal-chemistry-relevant heterocyclic substrates. Applicability in HTE and library synthesis, combined with its orthogonality to other cross-coupling reactions, make it highly attractive for discovery chemistry workflows. Additionally, the results suggest that the nature of the Cu(I)-carboxylate plays a more prominent role in the reaction performance than the nature of Pd-catalysts, which is rather uncommon for Pd-catalysis and can be used in further optimization of Liebeskind-Srogl coupling.

Mechanical properties of fracture-grouted prefabricated sandstone after thermal-acid coupling treatment: An experimental study

Grouting reinforcement is an efficient approach to increase the stability of engineered fractured rock masses that may be subjected to high temperatures and acidic groundwater in complex geological environments. To reveal the mechanical properties and failure characteristics of the grout-reinforced fractured rock masses under thermal-acid coupling conditions, prefabricated fractured red sandstone specimens with different inclination angles (IAs) were firstly grouted using a new high-strength fast anchoring agent (HSFAA). Then, the grout-reinforced specimens (GRSs) were then immersed in hydrochloric acid (HCl) solutions with different temperatures (varying from 25 to 300 °C). Finally, the macroscopic mechanical properties, microscopic morphology, and crack evolution characteristics of the GRSs after thermal and acid solution treatments were investigated by the uniaxial compression test, X-ray computed tomography (CT) and scanning electron microscopes (SEM). The results confirmed that the HSFAA featured with high fluidity, rapid setting, excellent early strength, and micro-expansion, was an ideal grouted reinforcement material for fractured rock masses. The compressive and tensile strengths of the HSFAA material at a 1-day curing were 2.01 and 1.64 times those of the ordinary Portland cement 42.5 (P.O 42.5), respectively. The fractured IA, thermal-acid coupling method and temperature affected the mass loss, strength parameters, and failure modes of the GRSs to different degrees. The thermal-acid coupling treatment affected the initiation location and extension direction of cracks within the GRSs. The increasing temperature led to the larger and more varied internal cracks, as well as the more complex 3D spatial morphology within the GRSs.

Optical Cavity Design and Functionality for Molecular Strong Coupling.

Optical cavity/molecule strong coupling offers attractive opportunities to modulate photochemical or photophysical processes. When atoms or molecules are placed in an optical cavity, they can coherently exchange photonic energy with optical cavity vacuum fields, entering the strong coupling interaction regime. Recent work suggests that the thermodynamic and kinetic properties of molecules can be significantly changed by strong coupling, resulting in the emergence of intriguing photochemical and photophysical phenomena. As more and more physico-chemical systems are studied under strong coupling conditions, optical cavities have also advanced in their sophistication, responsiveness, and (multi)functionality. In this review, we highlight some of these recent developments, particularly focusing on Fabry-Perot microcavities.

Study of the Effect of Continuous Thermal Effects on the Shear Stability of Magnetorheological Grease

Magnetorheological dampers in the service of the medium in a project experience continuous thermal effects, frequent reciprocating shear and other complex conditions. Shear stability is an important indicator of the reliability of a magnetorheological media service. Magnetorheological grease (MRG) was prepared using hydroxy iron powder with a mass fraction of 30% and lithium grease of different consistency grades as a continuous phase. The results of magnetic and rheological properties analysis were combined to investigate the mechanism of the continuous thermal effect on the shear stability of MRG. The results show that changes in the temperature field and magnetic field cause significant changes in the magnetic and rheological properties of MRG. At low temperatures and low magnetic fields, the soap fiber structure unique to MRG can effectively inhibit the movement of magnetic particles, with slight changes in the rheological properties and excellent shear stability. When the temperature increases to 80 °C, 00#MRG is damaged by the high temperature. The soap fiber structure is fractured and reorganized, and the rheological properties change significantly. However, the rheological properties of 1#MRG remain largely unchanged during the magnetic field enhancement to saturation, showing better shear stability. The higher consistency continuous phase has excellent heat resistance and better shear performance stability in the face of thermomagnetic coupling conditions, but the fiber breakage caused by continuous reciprocating shear poses a challenge to the service stability of MRG.

Stability Analysis of Surrounding Rock in Deep Underground Engineering Under Fluid-solid Interaction

The geological environment of deep rock masses is extreme and complex, characterized by typical deep geological features such as high geostress, high permeation water pressure, and high geotemperature. Geological disasters like water and mud inrush, high-intensity rock bursts, and large-volume collapses occur frequently in engineering construction, presenting more complex mechanisms of disaster than shallower rock masses and severely impacting the construction and operational safety of deep underground projects. Utilizing three-dimensional numerical simulation methods, this study investigated the deformation, stress, and plastic zone characteristics of surrounding rock under multi-field coupling conditions during the construction of deep caverns, revealing the stability influencing factors of deep caverns under multi-field coupling. A funnel-shaped precipitation area forms near the excavation surface of the cavern, gradually expanding as the initial pore water pressure increases. The concentration of seepage vectors in the sidewalls and arch feet continues to increase, with local seepage rates reaching 5.1×10^-6. The cavern's crown and sidewalls are particularly sensitive to changes in pore water pressure, with the maximum tensile stress appearing 1 m and 3 m axially along the sidewalls of the cavern. The plastic zone experiences its greatest increase at a water pressure of 4 MPa.

A Deep Learning Approach to Improve the Control of Dynamic Wireless Power Transfer Systems

In this paper, an innovative approach for the fast estimation of the mutual inductance between transmitting and receiving coils for Dynamic Wireless Power Transfer Systems (DWPTSs) is implemented. To this end, a Convolutional Neural Network (CNN) is used; an image representing the geometry of two coils that are partially misaligned is the input of the CNN, while the output is the corresponding inductance value. Finite Element Analyses are used for the computation of the inductance values needed for CNN training. This way, thanks to a fast and accurate inductance estimated by the CNN, it is possible to properly manage the power converter devoted to charge the battery, avoiding the wind up of its controller when it attempts to transfer power in poor coupling conditions.