Coupling Approach Research Articles

Multi-image encryption based on 3D space scrambling and new spatiotemporal chaotic system

This paper introduces a groundbreaking spatiotemporal chaotic system, named DCMLMDF, and a novel encryption method that synergizes scrambling and diffusion synchronization for multi-image encryption. The DCMLMDF system, which incorporates a dynamic coupling approach and a random delay feedback mechanism, significantly enhances the randomness and complexity of the encryption process. By applying this system within the newly designed multi-image encryption framework, the method achieves three-dimensional space scrambling and diffusion synchronization, overcoming traditional encryption challenges such as extended encryption time and periodic vulnerabilities. The results demonstrate that this innovative approach not only effectively confuses image data but also substantially improves overall system security, marking a significant advancement in the application of chaotic systems to image encryption.

Design of Oil Mist and Volatile-Organic-Compound Treatment Equipment in the Manufacturing Plant

To effectively confront the acute challenge of global warming, at the present stage, the Chinese government has designated carbon reduction as the core objective to accomplish the coordinated control of greenhouse gas and pollutant emissions. As China is a major manufacturing country, with the continuous improvement of air emission standards, it is particularly necessary to carry out the design of more efficient volatile organic pollutant emission devices. This study takes a treatment system with a waste gas ventilation volume of 6 × 104 m3·h−1 as an example, adopts the end treatment approach of adsorption and catalytic combustion coupling, and designs a purification device composed of multistage oil-mist recovery, electrostatic adsorption, dry filtration, activated-carbon adsorption and desorption, catalytic combustion, etc. It also employs the fuzzy proportional-integral-derivative fine temperature control algorithm, and the temperature overshoot was decreased by 85%. The average emission concentration of volatile organic compounds at the equipment outlet is 6.56 mg·m−3, and the average removal rate is 93.99%, far surpassing the national emission standards. The device operates efficiently and stably, confirming that the end-coupled treatment system based on the adaptive fuzzy proportional-integral-derivative temperature control strategy can effectively handle volatile organic compounds with oil mist and holds significant promotion and research value.

An interprocess communication-based two-way coupling approach for implicit–explicit multiphysics lattice discrete particle model simulations

In this study, the researchers have developed a Multiphysics-Lattice Discrete Particle Model (M-LDPM) framework that deals with coupled-fracture-poroflow problems. The M-LDPM framework uses two lattice systems, the LDPM tessellation and the Flow Lattice Element (FLE) network, to represent the heterogeneous internal structure of typical quasi-brittle materials like concrete and rocks, and to simulate the material’s mechanical and transport behavior at the aggregate scale. The researchers revisited the LDPM governing equations and added the influence of fluid pore pressure. They also derived the Flow Lattice Model (FLM) governing equations for pore pressure flow through mass conservation balances for uncracked and cracked volumes. The M-LDPM framework was implemented using Abaqus user element subroutine VUEL for the explicit dynamic procedure of LDPM and user subroutine UEL for the implicit transient procedure of FLM. The coupling of the two models was achieved using Interprocess Communication (IPC) between Abaqus solvers. The M-LDPM framework can simulate the variation of permeability induced by fracturing processes by relating the transport properties of flow elements with local cracking behaviors. The researchers validated the M-LDPM framework by comparing the numerical simulation outcomes with analytical solutions of classical benchmarks in poromechanics.

An automatic simulation pipeline for coupled simulations of acoustic damping materials

AbstractFoamed materials are widely used to reduce noise due to their comparably good acoustic damping behavior. However, out of a large variety of these materials a suitable candidate has to be identified for each application. This is a challenging process that is typically guided by experiments and experience. While numerical simulations could support these experiments and reduce the effort to a great extent, no suitable discretization approach has yet been established that can fully capture the complex geometry of the foam. A fully resolved model is desirable in order to yield reliable predictions that can then be used to establish homogenized models. We established a monolithic coupling approach based on the finite cell method (FCM) that realizes a vibroacoustic simulation in this sense. The fluid and the structure domain are discretized by Cartesian grids and the geometry defined based on computed tomography scans is accounted for during the quadrature of the weak form. Our simulation in the time domain makes use of explicit time marching schemes and is therefore limited by a critical time step size. This is known to be arbitrarily low for discretizations with the FCM containing cells with arbitrarily small support. As a remedy against this we use the classical ‐stabilization technique and investigate its potentials and limitations.

Investigation of the seismic response of irrigation channel using Coupled Eularian-Lagrangian approach

Investigation of the seismic response of irrigation channel using Coupled Eularian-Lagrangian approach

Thermal-mechanical coupling characteristics of large-scale molten salt storage tanks under stable operating conditions with varying liquid levels

The large-scale molten salt storage tank is a critical component of the thermal storage system employed in concentrating solar power (CSP) plants. The storage tank is subjected to complex conditions, including high temperature, fluctuating hydrostatic pressure, and thermal stress. Therefore, it is imperative to investigate the thermal-mechanical coupling characteristics of the tank during stable operation under varying liquid levels to comprehensively understand its behavior. The study commences by establishing thermal and stress analysis models for the tank, laying the foundation for subsequent investigation. Subsequently, a comprehensive thermal-mechanical coupling model is constructed using a sequential coupling approach, enabling a more accurate representation of the system's behavior. Finally, an in-depth study is conducted to explore the thermal-mechanical coupling characteristics of storage tanks at various liquid levels. The results indicate that radiation emitted by high-temperature air, confined in the top space of the tank, induces a temperature differential of approximately 5 °C between the tank's roof and the molten salt confined within it. Furthermore, heat loss from the roof accounts for 53 % of the overall heat loss. Thermal stress analysis of each weld seam connecting the tank into an integration reveals that the inner surface experiences tensile stress, while the outer surface undergoes compressive stress, primarily influenced by radial stress. Under the influence of thermal-mechanical, the coupling effect leads to compressive stress in the form of thermal stress, resulting in a decreasing trend in stress on the inner surface of the weld seam. The radial compressive stress on the outer surface reaches approximately 140 MPa, while the tank wall is primarily subjected to circumferential forces. The temperature exerts a negligible impact on the stress of the tank wall, yet it significantly affects its deformation. The stress evaluation of hydrostatic pressure and thermodynamic coupling under different liquid levels is carried out, and the results meet the strength requirements.

Simulating cross-scale flow dynamics around offshore monopile foundations with a GFD-CFD coupled model

Flow dynamics are complex and undergo significant impact from offshore engineering infrastructures, such as wind turbines, involving interactions across different temporal and spatial scales. Individual numerical models of geophysical fluid dynamics (GFD) or computational fluid dynamics (CFD) face challenges in accurately representing these dynamics. To effectively capture the three-dimensional cross-scale flow around offshore infrastructures, we propose a generalized coupling framework that integrates the unstructured-grid Finite-Volume Community Ocean Model (FVCOM) for GFD and the Open Field Operation and Manipulation (OpenFOAM) for CFD. With the validation against the flume experiment, the common-boundary nesting method was developed to allow an accurate representation of flow dynamics around offshore hydraulic infrastructures. Idealized monopile foundation experiments demonstrate the model's capability to capture the formation of Karman vortex street, rotating horseshoe vortex under realistic astronomical tidal conditions. Application of this coupling framework to the offshore wind farm in Yangjiang, China, reveals flow direction lagging of 15° in the wake of a monopile under diurnal tide. This coupling approach, leveraging the strengths of both CFD and GFD models, provides a universal downscaling methodology in geophysical conditions, for a better understanding of the impact of offshore hydraulic infrastructures on the surrounding environment and further planning offshore engineering projects.

Bulk properties of nuclear matter in a modified relativistic dirac formalism

In this study, we employ a phenomenologically modified relativistic Dirac framework coupled with the σ - ω quark-meson coupling model to look into the properties of nuclear matter. By combining scalar and vector linear potential forms and incorporating perturbative adjustments for various factors such as centre-of-mass motion, gluonic, and pionic effects, we aim to find the nucleon’s mass in a vacuum. Then, we consider nucleon-nucleon interactions are constructed within a mean-field approximation. Our methodology systematically explores key characteristics of nuclear matter, including equations of state, compressibility, binding energy, and pressure. Furthermore, we compute essential parameters such as the nucleon charge radius, axial-vector coupling constant, pion coupling constant, nuclear sigma term, sensitivity, and potential strengths. And also, we calculate symmetry energy, density slop (L) and incompressibility ( K0 ). In addition, we compute the mass and radius of a neutron star and provide a graphical representation illustrating the relationship between mass and radius. To validate our results, we comprehensively compare them with other theoretical models and quark-meson coupling approaches, confirming the precision and reliability of our theoretical paradigm. Overall, our study enhances our understanding of the fundamental properties of nuclear matter and underscores their relevance in elucidating complex astrophysical phenomena.

Thermo-neutronic integrated coupling effects on nuclear reactor core calculations

Small Modular Reactors (SMRs) have gained significant attention as the next generation of nuclear reactors due to their unique features, such as improved economic viability and safety. This study focuses on the SMART reactor, the first certified design of an SMR, and investigates various Thermo-Neutronics aspects using an integrated coupling scheme of nuclear codes. The Neutronics cell and core calculations are performed using the DRAGON/DONJON codes, while the COBRA code is employed for thermal-hydraulic calculations. The analysis considers parameters including axial and radial power peaking factors (PPFs), critical heat flux (CHF), minimum departure from nucleate boiling ratio (MDNBR), axial average coolant temperature in hot channel and core, and maximum fuel temperature. These parameters are evaluated using the developed coupling system. Code-to-code verification is conducted to ensure the accuracy of the results, demonstrating good agreement. The coupling approach reveals significant effects compared to stand-alone code modeling, emphasizing the importance of considering the coupling between Neutronics and thermal-hydraulics, especially during the cycle length. This study contributes to the understanding of SMRs, particularly the SMART reactor, by providing insights into key parameters and their interdependencies. The integrated coupling scheme enhances the accuracy of the analysis and highlights the significance of considering coupling effects in the modeling process during the steady state and the cycle length.

A parallel coupling framework for DEM-MBD: Model verification and application

Bulk material handling equipment can be numerically studied using the DEM-MBD method, where the particulate dynamics are solved by DEM (Discrete Element Method) and the motion characteristics of the mechanical components are modeled by MBD (Multi-Body Dynamics). In this work, a two-way coupling framework is proposed for the co-simulation of our self-developed DEM solver (DEMSLab) with the commercial MBD software (RecurDyn) using a parallel staggered coupling approach. To verify the proposed coupling method, the simulation result of a torsional spring damper system is compared with the corresponding analytical solution. After that, to assess the feasibility of this method in industrial-scale applications, a series of simulations involving a wheel loader is carried out. Different simulation conditions are adopted to reveal their impact on computational efficiency and simulation accuracy. These conditions include the mesh representation of the equipment geometry, the MBD time step size, and the coupling interval. An improved mesh simplification algorithm is proposed and used to reasonably simplify the surface mesh of the wheel loader, thus lowering the computational intensity of particle-wall interactions in DEM. The comparison results indicate that the computational time can be largely saved while the simulation accuracy remains considerably high. The MBD step size and coupling interval are crucial for numerical stability and should be selected carefully.

TBHP Promotes Cross-Dehydrogenative Coupling of SF4 Alkynes with Tetrahydroisoquinolines under Copper Catalysis.

We present a viable approach for the cross-dehydrogenative coupling of Het-SF4-alkynes with tetrahydroisoquinolines under oxidative conditions, using TBHP and copper catalysts. These newly developed conditions boast enhanced yields and a more extensive range of substrates, demonstrating tolerance to various functional groups and addressing the limitations of earlier reports. Consequently, this method should increase opportunities for the exploration of SF4-containing compounds and their potential applications in drug discovery, materials science, and as alternatives to PFAS.

Hemilabile and Redox‐Active Quinone Ligands Unlock sp3‐Rich Couplings in Nickel‐Catalyzed Olefin Carbosulfenylation

A three‐component coupling approach toward structurally complex dialkylsulfides is described via the nickel‐catalyzed 1,2‐carbosulfenylation of unactivated alkenes with organoboron nucleophiles and alkylsulfenamide (N–S) electrophiles. Efficient catalytic turnover is facilitated using a tailored N–S electrophile containing an N‐methyl methanesulfonamide leaving group, allowing catalyst loadings as low as 1 mol%. Regioselectivity is controlled by a collection of monodentate, weakly coordinating native directing groups, including sulfonamides, amides, sulfinamides, phosphoramides, and carbamates. Key to the development of this transformation is the identification of quinones as a family of hemilabile and redox‐active ligands that tune the steric and electron properties of the metal throughout the catalytic cycle. DFT calculations show that the duroquinone (DQ) ligand adopts different coordination modes in different stages of the Ni‐catalyzed 1,2‐carbosulfenylation—binding as an η6 capping ligand to stabilize the precatalyst/resting state and prevent catalyst decomposition, binding as an X‐type redox‐active durosemiquinone radical anion to promote alkene migratory insertion with a less distorted square planar Ni(II) center, while binding as an η1 L‐type ligand to promote N–S oxidative addition at a relatively more electron‐rich and sterically less crowded Ni(I) center.

Hemilabile and Redox-Active Quinone Ligands Unlock sp3-Rich Couplings in Nickel-Catalyzed Olefin Carbosulfenylation.

A three-component coupling approach toward structurally complex dialkylsulfides is described via the nickel-catalyzed 1,2-carbosulfenylation of unactivated alkenes with organoboron nucleophiles and alkylsulfenamide (N-S) electrophiles. Efficient catalytic turnover is facilitated using a tailored N-S electrophile containing an N-methyl methanesulfonamide leaving group, allowing catalyst loadings as low as 1 mol%. Regioselectivity is controlled by a collection of monodentate, weakly coordinating native directing groups, including sulfonamides, amides, sulfinamides, phosphoramides, and carbamates. Key to the development of this transformation is the identification of quinones as a family of hemilabile and redox-active ligands that tune the steric and electron properties of the metal throughout the catalytic cycle. DFT calculations show that the duroquinone (DQ) ligand adopts different coordination modes in different stages of the Ni-catalyzed 1,2-carbosulfenylation-binding as an η6 capping ligand to stabilize the precatalyst/resting state and prevent catalyst decomposition, binding as an X-type redox-active durosemiquinone radical anion to promote alkene migratory insertion with a less distorted square planar Ni(II) center, while binding as an η1 L-type ligand to promote N-S oxidative addition at a relatively more electron-rich and sterically less crowded Ni(I) center.

Base-Filling in Double-Helical Nucleic Acids.

Base-filling, i. e., post-synthetic furnishing of an oligonucleotide scaffold with base moieties or their analogues, is an interesting alternative to the conventional approach of sequential coupling of building blocks (modified or otherwise). Reversible attachment of the base moieties is particularly attractive as it allows the use of dynamic combinatorial chemistry and usually leads to higher fidelity. This concept article summarizes the various backbones and coupling reactions used for base-filling over the past fifteen years, discusses the impact of base stacking and pairing on efficiency and fidelity and highlights potential and realized applications.

Kinetic investigation of discharge performance for Xe, Kr, and Ar in a miniature ion thruster using a fast converging PIC-MCC-DSMC model

Abstract The present work develops a full particle-based model that couples the particle-in-cell plus Monte Carlo collision (PIC-MCC) simulation for plasma dynamics and the direct simulation Monte Carlo (DSMC) method for neutral dynamics in a synergistic iterative manner. This new model overcomes the slow convergence issue in the conventional direct coupling approach caused by the disparity of the time scales between the plasma and neutral dynamics. This model is applied to simulate the behavior of xenon (Xe) and its potential alternatives, krypton (Kr) and argon (Ar), in the discharge chamber of a miniature direct current (DC) ion thruster. The results show that a stable discharge is difficult to achieve for Kr and Ar under the operating conditions optimal for Xe. While increasing the discharge voltage can effectively improve the stability of discharge for Kr and Ar, other common strategies such as changing the magnetic field strength, propellant flow rate, and cathode current are not successful. The propellant utilization efficiency and discharge efficiency are affected by both discharge voltage and propellant flow rate. A maximum utilization efficiency and an optimal discharge efficiency are observed for all three propellants, with the values decreasing in the order of Xe, Kr, and Ar. Moreover, the discharge voltage corresponding to the optimal efficiency is inversely proportional to the square root of the propellant mass, indicating that the ion diffusional loss to the wall, rather than the ionization energy, is the dominant factor affecting the discharge performance for alternative propellants in a miniature DC thruster.

Four-port dual-band textile MIMO antenna for biomedical health monitoring systems: on-body mutual coupling reduction characterization

The paper outlines a methodology to diminish mutual coupling in 4-port dual-band MIMO textile antenna for biomedical applications. This antenna leverages MIMO technology and Wireless Body Area Network (WBAN) for operation in two distinct frequency bands at (3.5 & 2.45 GHz). The antenna is made up of four octagonal patch antennas, each having a bar and a split-ring (SR) slot with 47.2 × 31 mm2 dimensions for each patch. A hybrid mutual coupling (MC) approach was investigated with closely spaced patches (up to 0.05λ). Various bending setups have been selected along with flat case to examine the antennas’ resilience which demonstrate such agreement between measured and simulated findings. Furthermore, the MC is only −20 dB, the envelope correlation coefficient (ECC) is 0.001, and maximum peak measured gain of 5.2 dBi is achieved with lowest peak specific absorption rate (SAR) value. Even when bent at a 60° angle along with y-axis and x-axis, the antenna retains a decent gain of 1.861 dBi in the low frequency region and 5.479 dBi at high frequency band. Surprisingly, the antenna outperforms the attenuation produced by the lossy effects of the human body, indicating a favorable alignment between the modelled and observed findings.

A Click-Type Enzymatic Method for Antigen-Adjuvant Conjugation.

The Toll-like receptor 9 (TLR9) stimulator, CpG oligodeoxynucleotide, has emerged as a potent enhancer of protein subunit vaccines. Incorporating the protein antigen directly with the CpG adjuvant presents a novel strategy to significantly reduce the required dosage of CpG compared to traditional methods that use separate components. In contrast to existing chemical conjugation methods, this study introduces an enzymatic approach for antigen-adjuvant coupling using a recombinant endonuclease DCV fused with SpyTag. This fusion protein catalyzes the covalent linkage between itself and the CpG adjuvant under mild conditions. These conjugates can be further linked with target protein antigens containing the SpyCatcher sequence, yielding stable, covalently-linked antigen-adjuvant complexes. The corresponding complex utilizing the receptor-binding domain (RBD) of SARS-CoV-2 spike protein as the model antigen, elicits high-titer, specific antibody production in mice via both subcutaneous administration and intratracheal inoculation. Notably, the tumor vaccine candidate fabricated by this method has also shown significant inhibition of cancer progression after intratracheal administration. The technique ensures precise, site-specific coupling and preserves the antigen's structural integrity due to the post-purification coupling strategy that simplifies manufacturing and aids in developing inhalable vaccines.

Numerical investigation of thermal soak within engine bay using lattice Boltzmann method

A large amount of heat accumulates in the engine bay for a short time after the engine runs at high load and shuts down, that will lead to thermal damage and thermal fatigue caused by the temperature rise of some heat sensitive components. This paper uses an aero-thermal coupling approach to study the heat transfer problem in the engine bay of an SUV model under thermal soak conditions. Due to the transient characteristics of the heat transfer process, the natural transient CFD software developed based on the LBM method is used to study the engine bay heat transfer during the 400 s key-off soak process. The analysis reveals that convection and radiation are the main heat transfer modes in the early stage of hot immersion (0–120 s), and conduction only makes a significant contribution in contact with high temperature sources. The radiation and convection are the key contributors to heat transfer processes of engine bay during soak, but the efficiency of radiation heat transfer decreases with the increase of time, whereas the efficiency of convection heat transfer is not always reduced, it will increase and then decrease with the increase of time. The coupling method established can predict the thermal state in the engine bay well, and is in good agreement with the experimental results. The results show that the error in the engine coolant temperature is less than 1 °C, and the error in the temperature of the heat-sensitive components is less than 5 °C. Finally, the potential risks of thermal damage and thermal fatigue states were assessed, providing an important reference for the control design of cooling fan running time after key-off.

Synthesis of Stereodefined Enones from the Cross-Electrophile Coupling of Activated Acrylic Acids with Alkyl Bromides.

We report a one-pot synthesis of (E)-trisubstituted enones from acrylic acids through the in situ generation of a 2-pyridyl ester and subsequent cross-electrophile coupling with a nickel catalyst under reducing conditions. The scope of trisubstituted enones is broad and compatible with functionality that can be challenging in established olefination techniques. We highlight conditions necessary to suppress undesired side reactions from the α,β-unsaturated carbonyl and improve cross-electrophile coupling approaches to prepare enones.

Superposition‐based concurrent multiscale approaches for porodynamics

AbstractThe current study presents superposition‐based concurrent multiscale approaches for porodynamics, capable of capturing related physical phenomena, such as soil liquefaction and dynamic hydraulic fracture branching, across different spatial length scales. Two scenarios are considered: superposition of finite element discretizations with varying mesh densities, and superposition of peridynamics (PD) and finite element method (FEM) to handle discontinuities like strain localization and cracks. The approach decomposes the acceleration and the rate of change in pore water pressure into subdomain solutions approximated by different models, allowing high‐fidelity models to be used locally in regions of interest, such as crack tips or shear bands, without neglecting the far‐field influence represented by low‐fidelity models. The coupled stiffness, mass, compressibility, permeability, and damping matrices were derived based on the superposition‐based current multiscale framework. The proposed FEM‐FEM porodynamic coupling approach was validated against analytical or numerical solutions for one‐ and two‐dimensional dynamic consolidation problems. The PD‐FEM porodynamic coupling model was applied to scenarios like soil liquefaction‐induced shear strain accumulation near a low‐permeability interlayer in a layered deposit and dynamic hydraulic fracturing branching. It has been shown that the coupled porodynamic model offers modeling flexibility and efficiency by taking advantage of FEM in modeling complex domains and the PD ability to resolve discontinuities.