A moving least square immersed boundary method for SPH with thin-walled structures

This paper presents a novel method for smoothed particle hydrodynamics (SPH) with thin-walled structures. Inspired by the direct forcing immersed boundary method, this method employs a moving least square method to guarantee the smoothness of velocity near the structure surface. It simplifies thin-walled structure simulations by eliminating the need for multiple layers of boundary particles, and improves computational accuracy and stability in three-dimensional scenarios. Supportive three-dimensional numerical results are provided, including the impulsively started plate and the flow past a cylinder. Results of the impulsively started test demonstrate that the proposed method obtains smooth velocity and pressure in the, as well as a good match to the references results of the vortex wake development. In addition, results of the flow past cylinder test show that the proposed method avoids mutual interference on both side of the boundary, remains stable for three-dimensional simulations while accurately calculating the forces acting on structure.Comment: 15 pages,11 figure

Input files for LBM-DEM simulation of immersed granular collapse

The input files for the case D-VB. The files with the name started with "in" are input files for LIGGGHTS (https://github.com/CFDEMproject/LIGGGHTS-PUBLIC) and the C++ file is the input file for Palabos (http://www.palabos.org/). The input files are called in the following sequence: 1. in.cloud - generate the particles 2. in.rain - create a granular column by turning on the gravity 3. in.trim - trim the particles so that the aspect ratio is 0.8 4. damBreakImmersed.cpp - solve fluid filed using LBM 5. in.immerse - immersed the granular column 6. in.cycle - called by "damBreakImmersed.cpp" to advance the DEM simulation Other cases with different column sizes and packing densities can be simulated by the same input files with adjustments on the geometry and friction coefficients during sample preparation

High-Performance Asymmetric Supercapacitor Based on Nanoarchitectured Polyaniline/Graphene/Carbon Nanotube and Activated Graphene Electrodes

Hierarchical sulfonated graphene nanosheet/carboxylated multiwalled carbon nanotube/polyaniline (sGNS/cMWCNT/PANI) nanocomposites were synthesized through an interfacial polymerization method. Activated porous graphene (aGNS) was prepared by combining chemical foaming, thermal reduction, and KOH activation. Furthermore, we have successfully fabricated an asymmetric supercapacitor (ASC) using sGNS/cMWCNT/PANI and aGNS as the positive and negative electrodes, respectively. Because of its unique structure, high capacitive performance, and complementary potential window, the ASC device can be cycled reversibly at a cell voltage of 1.6 V in a 1 M H₂SO₄ aqueous electrolyte, delivering a high energy density of 20.5 Wh kg^–1 at a power density of 25 kW kg^–1. Moreover, the ASC device also exhibits a superior long cycle life with 91% retention of the initial specific capacitance after 5000 cycles

A Novel Flexible Supercapacitor Based on Cross-Linked PVDF-HFP Porous Organogel Electrolyte and Carbon Nanotube Paper@π-Conjugated Polymer Film Electrodes

High energy density and safety are the goals in the pursuit of flexible energy storage devices. Herein, we report a novel flexible supercapacitor (SC) fabricated with a cross-linked poly­(vinylidene fluoride-<i>co</i>-hexafluoropropylene) (PVDF-HFP) porous organogel electrolyte and carbon nanotube paper@poly­(1,5-diaminoanthraquinone) (CNT@PDAA) film electrodes. The PVDF-HFP/tetraethylammonium tetrafluoroborate-acetonitrile (Et₄NBF₄-AN) organogel electrolyte, featured with a highly porous structure and chemical cross-linking, exhibits nonflammability, a broad electrochemical stable window, and high ionic conductivity of 14.4 × 10^–3 S cm^–1, as well as improved solvent resistance. The CNT@PDAA electrode displays good pseudocapacitive performance in a broad potential window due to p- and n-doping characteristics. Because of this rational design, the as-prepared flexible SC device achieves an excellent volumetric capacitance of 5.2 F cm^–3 and a high energy density of 5.16 mWh cm^–3 (41.4 Wh kg^–1) at a power density of 0.051 W cm^–3 (0.41 kW kg^–1). More importantly, a unit of as-assembled SC is shown to drive a commercially available product even in a bent state

High energy-density organic supercapacitors based on optimum matching between GNS/aMWCNT@polyaniline nanocone arrays cathode and GNS/aMWCNT@poly(1,5-diaminoanthraquinone) nanoparticles anode

Nowadays, high energy density is greatly imperative for supercapacitor technologies, which focus on both high-performance electrodes and assembling techniques. Here, we synthesized a promising cathode of graphene/acid-treated carbon nanotubes (GNS/aMWCNT)-supported polyaniline nanocone arrays by an interfacial polymerization, which achieves high specific capacitance of 299 F g−1 in 1 M tetraethylammonium tetrafluoroborate-acetonitrile (Et4NBF4-AN) with the potential window of −0.6 to 0.8 V (vs. Ag/Ag+). Matching it with GNS/aMWCNT-supported poly(1,5-diaminoanthraquinone) nanoparticles anode, the organic asymmetric supercapacitors (oASCs) are perfectly fabricated. The oASC with anode/cathode mass ratio of 1/1 delivers the highest energy density of 96.9 Wh kg−1, excellent rate capability (retain 65.6 Wh kg−1 even at 65.7 kW kg−1) and superior cycling stability (94.2% retention after 5000 cycles), which is superior or comparable to other π-conjugated polymers-based organic supercapacitors. © 2017 Elsevier B.V.China Postdoctoral Science Foundation; 51173042, NSFC, National Natural Science Foundation of China; 51673064, NSFC, National Natural Science Foundation of ChinaNational Natural Science Foundation of China [51673064, 51173042]; Shanghai Municipality Research Project [15520720500]; China Postdoctoral Science Foundation [2016M601502]; International Science & Technology Cooperation Program of China [2016YFE0131200

Enhancing the Energy Density of Asymmetric Stretchable Supercapacitor Based on Wrinkled CNT@MnO₂ Cathode and CNT@polypyrrole Anode

With the advantages of high stickiness and stretchability of the hydrogel electrolyte as well as the resilient properties of film electrodes, the facile “prestrain-stick-release” strategy can be utilized for the assembly of a stretchable supercapacitor. Two major issues of concern are the relatively low mechanical strength of the hydrogel electrolyte and the low energy density of the assembled device. Herein, vinyl group grafted silica (CH₂CHSiO₂) nanoparticles were used as a nanoparticle cross-linker for polyacrylamide (PAAM), enhancing the tensile strength of 844 kPa at the strain of 3400% for the KClCH₂CHSiO₂/PAAM hydrogel electrolyte. Besides, carbon nanotube supported polypyrrole (CNT@PPy) and manganese dioxide (CNT@MnO₂) film electrodes are prepared to assemble the stretchable asymmetric CNT@MnO₂//KClCH₂CHSiO₂/PAAM//CNT@PPy supercapacitor, significantly enhancing the potential window to 0–2.0 V and achieving a high energy density of 40 Wh kg^–1 at the power density of 519 kW kg^–1 with the strain of 100%, which is the best known for the reported stretchable supercapacitors

Microgel-Enhanced Double Network Hydrogel Electrode with High Conductivity and Stability for Intrinsically Stretchable and Flexible All-Gel-State Supercapacitor

In the present work, a new strategy is proposed to simultaneously enhance the toughness and electrochemical performance of the hydrogel with conductive microgel to form microgel-reinforced double network hydrogel. In this hydrogel, the conductive microgel is cross-linked to form the first network, which can dissipate energy to improve mechanical performance and stabilize the conductive network to improve the electrochemical performance. These hydrogels show excellent mechanical properties and good conductivity. When these hydrogels are assembled to all-gel-state intrinsically flexible and stretchable supercapacitor, they deliver outstanding capacitance. The strategy put forward here can extend the application scope of the hydrogel with multifunction

Microgel-Enhanced Double Network Hydrogel Electrode with High Conductivity and Stability for Intrinsically Stretchable and Flexible All-Gel-State Supercapacitor

In the present work, a new strategy is proposed to simultaneously enhance the toughness and electrochemical performance of the hydrogel with conductive microgel to form microgel-reinforced double network hydrogel. In this hydrogel, the conductive microgel is cross-linked to form the first network, which can dissipate energy to improve mechanical performance and stabilize the conductive network to improve the electrochemical performance. These hydrogels show excellent mechanical properties and good conductivity. When these hydrogels are assembled to all-gel-state intrinsically flexible and stretchable supercapacitor, they deliver outstanding capacitance. The strategy put forward here can extend the application scope of the hydrogel with multifunction

Microgel-Enhanced Double Network Hydrogel Electrode with High Conductivity and Stability for Intrinsically Stretchable and Flexible All-Gel-State Supercapacitor

In the present work, a new strategy is proposed to simultaneously enhance the toughness and electrochemical performance of the hydrogel with conductive microgel to form microgel-reinforced double network hydrogel. In this hydrogel, the conductive microgel is cross-linked to form the first network, which can dissipate energy to improve mechanical performance and stabilize the conductive network to improve the electrochemical performance. These hydrogels show excellent mechanical properties and good conductivity. When these hydrogels are assembled to all-gel-state intrinsically flexible and stretchable supercapacitor, they deliver outstanding capacitance. The strategy put forward here can extend the application scope of the hydrogel with multifunction