In this study, the wetting behavior of Sn solder on Cu substrate under ultrasonic vibration using the sessile drop method was investigated. The distribution of the vibration field on the substrate ...surface was analyzed via COMSOL Multiphysics finite element analysis, while the spreading behavior and interfacial reaction products of intermetallic compounds (IMCs) induced by varying ultrasonic amplitudes were explored. ultrasonic vibration demonstrates a significant influence on both wettability and interfacial reaction products. The wetting mechanism under ultrasonic vibration is primarily attributed to physical driving forces generated by ultrasound-induced interfacial viscous boundary layers, along with chemical driving forces facilitated by ultrasonic-accelerated interfacial atomic diffusion and reactions.
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•Study of the effect of ultrasonic vibration on wetting from interfacial reaction products and spreading processes.•Combined finite element and experimental methods to study the vibration field distribution.•Calculated physical driving forces in the interfacial viscous boundary layer induced by ultrasonic vibrations.•Interfacial physical and chemical drivers work together to promote wetting.
•First publicly available COMSOL implementation of phase field models for static and dynamic fracture in 2D and 3D.•Validated COMSOL code for phase field model for fracture.
The phase-field model ...(PFM) represents the crack geometry in a diffusive way without introducing sharp discontinuities. This feature enables PFM to effectively model crack propagation compared with numerical methods based on discrete crack model, especially for complex crack patterns. Due to the involvement of “phased field”, phase-field method can be essentially treated a multifield problem even for pure mechanical problem. Therefore, it is supposed that the implementation of PFM based on a software developer that especially supports the solution of multifield problems should be more effective, simpler and more efficient than PFM implemented on a general finite element software. In this work, the authors aim to devise a simple and efficient implementation of phase-field model for the modelling of quasi-static and dynamic fracture in the general purpose commercial software developer, COMSOL Multiphysics. Notably only the tensile stress induced crack is accounted for crack evolution by using the decomposition of elastic strain energy. The width of the diffusive crack is controlled by a length-scale parameter. Equations that govern body motion and phase-field evolution are written into different modules in COMSOL, which are then coupled to a whole system to be solved. A staggered scheme is adopted to solve the coupled system and each module is solved sequentially during one time step. A number of 2D and 3D examples are tested to investigate the performance of the present implementation. Our simulations show good agreement with previous works, indicating the feasibility and validity of the COMSOL implementation of PFM.
This work investigates the electrical field distribution in polymeric electrodes, materials composed of polymers and nanoparticles that leverage the physicochemical interactions between constituents ...to modify mechanical and electrical properties. Polymeric matrices often incorporate carbon nanoparticles to impart specific conductive properties while simultaneously enhancing mechanical stability through a protective polymer layer. The morphology, dielectric properties, and geometric configuration of these materials influence the electric field distribution, which is critical to their functionality. Utilizing finite element modeling, this study not yet explored aims to predict these effects and guide the design of material compositions and structural geometries to optimize functionalities like catalytic activity, adhesion enhancement, and interface energy reduction. Simulations were conducted using COMSOL 6.0 across eight similar geometric configurations, assessing polarization, and electric potential distribution. Results underscore the importance of surface polarization in controlling roughness and optimizing biosensor performance for liquid samples. Notably, controlled surface roughness induces asymmetric electric field distortions at biosensor edges, influencing dipole moments in polarizable nanoparticles. Each tested geometry demonstrated unique characteristics pertinent to its application in 3D-printed biosensors, influenced by surface roughness and wettability. Additionally, modifications in the electrical double layer due to controlled roughness alter charge distributions at the electrode-electrolyte interface, affecting electric field configurations.
•Computational tools can simulate the electric field distribution and predict the effects in a polymeric electrode system.•Controlled roughness surface causes non-symmetrical distortion in the electric field on the biosensor•Polymeric biosensor simulations show a contour effect in polarization behavior caused by the surface topography.•The polymeric biosensor geometry affects the density of electric field lines and gradients creating new charge regions.
This paper presents a comprehensive study on phase-field modelling in COMSOL MultiPhysics for simulating dynamic hydraulic fracturing in porous media based on Biot’s poro-elasticity theory. The focus ...is on addressing the challenges associated with crack width estimation in this context. A new strain-based crack width formulation is proposed, offering improved accuracy in predicting fracture permeability and ease of implementation in numerical approaches. The model’s capabilities are extended to consider dynamic crack propagation by incorporating the kinetic energy in the governing coupled hydro-mechanical-damage equations. The numerical implementations in COMSOL MultiPhysics are thoroughly explained, providing insights into the techniques used to solve the governing equations. Verification examples, including the benchmark KGD verification, are presented to demonstrate the model’s capabilities in simulating hydraulic fractures in porous media and validate its accuracy and reliability. A final numerical example focusing on the dynamics of crack propagation in a gravity dam is simulated, allowing for a comprehensive examination of the model’s performance. The proposed strain-based crack width formulation and consideration of dynamic crack propagation contribute to improved accuracy in predicting fracture permeability.
CuxO-Ag@CNFs framework with gradient lithiophilic structure is used to adjust the distribution of electric field strength on anode surface, make it homogenized and prevent excessive concentration of ...charge, realizing dendrite-free growth. We use COMSOL simulation to confirm this point, and the cell shows excellent electrochemical performance and practical potential in the testing of coin cell and pouch cell.
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•3D gradient lithiophilic framework CuxO-Ag@CNFs was synthesized by a low-cost electroplating method.•DFT calculation shows that the lithiophilic framework has high adsorption energy for lithium atom.•Uniform distributions of Li+ and surface electric field of the framework were simulated by COMSOL.•The capacity of CAC-Li|LFP pouch cell reached 138.5 mAh g−1 after 200 cycles at 0.1C.
Uncontrolled dendrite growth restricts the application of lithium metal battery as next-generation batteries. Herein, a 3D gradient lithiophilic framework (CuxO-Ag@CNFs) was constructed by multi-step electrochemical deposition. The symmetric cell can work steadily for 1000 h under low voltage hysteresis conditions at high current and large capacity (10 mA cm−2, 10 mAh cm−2). DFT calculation confirms the difference of lithiophilicity between CuxO, Ag and CuxO-Ag. The gradient structure of CuxO-Ag@CNFs was demonstrated by multiple structural characterization. COMSOL was used to simulate the distribution trend of Li+ concentration and electric field strength on the surface of the framework and verify the role of the composite material in homogenizing the electric field strength. The excellent performance of Li metal composite anode was attributed to the gradient distribution of CuxO and Ag on the CNFs with good lithiophilic property, which can achieve uniform local current density, form a stable SEI layer of Li2O and confine volume expansion ability of Li. Finally, LiFePO4 and CuxO-Ag@CNFs-Li were used as cathode and anode respectively, in full cell, which exhibited the potential for practical applications with superior cycling stability and good rate performance.
Magnesium (Mg) has good physical properties including light weight, excellent specific strength and high stiffness, and Mg is used in many fields. But current production methods of Mg have ...disadvantages, such as the generation of sulfur oxide and chlorine gas. In this situation, The Korea Institute of Geoscience and Mineral Resources (KIGAM) developed a Molten Salt Electrolysis Using Liquid Metal Cathode (MSELMC) method to produce high-purity magnesium. The MSE-LMC method can obtain 99.998-99.999% highpurity magnesium by the electrolysis of MgO dissolved in (MgF 2 )-LiF molten salt at 1053-1083 K, and by vacuum distilling an alloy generated by reacting with a metallic liquid cathode at 1200-1300 K. This study developed a numerical analysis model using COMSOL Multiphysics electrodeposition module to optimize the design of the electrolysis process. The model temperature was 1053K and molten salt was 54MgF 2 -46LiF with a 0.6wt% MgO system. 10A constant current was applied at the anode. This model uses the Butler-Volmer equation and the Nernst equation for the electric reaction. The Stokes-Einstein equation and Nernst-Einstein relation were used to calculate the diffusivity and electric mobility of salts. Unlike the experiment, in this model chlorine gas was generated. However, this model satisfied Faraday’s law. Therefore we define a new parameter using electric flux and voltage to conduct a quantitative evaluation according to the electrode shape, and compared that parameter by the changing angle of the anode.
(Received 16 February, 2023; Accepted 10 May, 2023)
Blocking electrochemistry, a subfield of single-entity electrochemistry, enables in-situ sizing of redox-inactive particles. This method exploits the adsorptive impact of individual insulating ...particles on a microelectrode, which decreases the electrochemically active surface area of the electrode. Against the background of an electroactive redox reaction in solution, each individual impacting particle results in a discrete current drop, with the magnitude of the drop corresponding to the size of the blocking particle. One significant limitation of this technique is “edge effects”, resulting from the inhomogeneous flux of the redox species’ diffusion due to increased mass transport to the edge of the disk electrode surface. “Edge effects” cause increased errors in size detection, resulting in poor analytical precision. Here, we use computational simulations to demonstrate that inhomogeneous diffusional edge flux of quasi-reversible redox species is mitigated at lowered overpotentials. This phenomenon is further illustrated experimentally by lowering the applied potential such that the system is operating under a kinetically-controlled regime instead of a diffusion-limited regime, which mitigates edge effects and increases particle sizing precision significantly. In addition, we found this method to be generalizable, as the precision enhancement is not limited to geometrically spherical particles but also occurs for cubic particles. This work presents a simple, novel methodology for edge effect mitigation with general applicability across different particle types.
•Theoretical confirmation of good BDD(·OH) generation in the novel pre-pilot batch reactor.•Faster degradation of ciprofloxacin in sulfate medium at higher j, concentration, and pH.•Degradation ...enhancement in chloride medium by additional attack of active chlorine.•Inhibitory effect of carbonate and humic acid, as well as in tap water and synthetic urine.•Formation of nitrate, nitrite, ammonia, and recalcitrant acetic, oxalic, and formic acids.
This paper presents the theoretical and experimental confirmation of the performance of a novel pre-pilot reactor design implementing a boron-doped diamond (BDD) anode to destroy emerging pollutants by electrochemical oxidation. Turbulent flow simulation and secondary current distribution modeling with a COMSOL Multiphysics software were used to assess the engineering capabilities of the reactor along with the oxidant BDD(·OH) electrogeneration at the anode. The antibiotic ciprofloxacin (CIP) was chosen as model molecule to assess the oxidation power achieved with the pre-pilot batch plant. In sulfate medium where BDD(·OH) was the main oxidant, faster degradation was determined by increasing current density, CIP content, and pH. The effect of pH was explained by the transformation of the cationic form of CIP in acidic medium into its more easily oxidizable anionic form in alkaline medium. In chloride medium, CIP was more rapidly removed by the faster attack of the generated active chlorine. The degradation was decelerated in carbonate medium by its scavenging effect and in the presence of humic acid by its competitive oxidation with BDD(·OH). The antibiotic abatement also dropped down in tap water and synthetic urine. An almost total mineralization was achieved with a constant energy cost per unit COD mass of 0.6 ± 0.1 kWh (g COD)−1. The initial N of CIP was pre-eminently converted into nitrate, alongside nitrite and ammonia to lesser extent. Recalcitrant acetic, oxalic, and formic acids were detected as final carboxylic acids.
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