Recent Research on Preparation and Application of Smart Joule Heating Fabrics

Multifunctional wearable heaters have attracted much attention for their effective applications in personal thermal management and medical therapy. Compared to passive heating, Joule heating offers significant advantages in terms of reusability, reliable temperature control, and versatile coupling. Joule-heated fabrics make wearable electronics smarter. This review critically discusses recent advances in Joule-heated smart fabrics, focusing on various fabrication strategies based on material-structure synergy. Specifically, various applicable conductive materials with Joule heating effect are first summarized. Subsequently, different preparation methods for Joule heating fabrics are compared, and then their various applications in smart clothing, healthcare, and visual indication are discussed. Finally, the challenges faced in developing these smart Joule heating fabrics and their possible solutions are discussed.

Microheater Chips with Carbon Nanotube Resistors

The specific and excellent properties of the low-dimensional nanomaterials have made them promising building blocks to be integrated into microelectromechanical systems with high performances. Here, we present a new microheater chip for in situ TEM, in which a cross-stacked superaligned carbon nanotube (CNT) film resistor is located on a suspended SiNx membrane via van der Waals (vdW) interactions. The CNT microheater has a fast high-temperature response and low power consumption, thanks to the micro/nanostructure of the CNT materials. Moreover, the membrane bulging amplitude is significantly reduced to only ∼100 nm at 800 °C for the vdW interaction between the CNTs and the SiNx membrane. An in situ observation of the Sn melting process is successfully conducted with the assistance of a customized flexible temperature control system. The uniform wafer-scaled CNT films enable a high level of consistency and cost-effective mass production of such chips. The as-developed in situ chips, as well as the related techniques, hold great promise in nanoscience, materials science, and electrochemistry.

Thermoelectric Limitations of Graphene Nanodevices at Ultrahigh Current Densities

Graphene is atomically thin, possesses excellent thermal conductivity, and is able to withstand high current densities, making it attractive for many nanoscale applications such as field-effect transistors, interconnects, and thermal management layers. Enabling integration of graphene into such devices requires nanostructuring, which can have a drastic impact on the self-heating properties, in particular at high current densities. Here, we use a combination of scanning thermal microscopy, finite element thermal analysis, and operando scanning transmission electron microscopy techniques to observe prototype graphene devices in operation and gain a deeper understanding of the role of geometry and interfaces during high current density operation. We find that Peltier effects significantly influence the operational limit due to local electrical and thermal interfacial effects, causing asymmetric temperature distribution in the device. Thus, our results indicate that a proper understanding and design of graphene devices must include consideration of the surrounding materials, interfaces, and geometry. Leveraging these aspects provides opportunities for engineered extreme operation devices.

MHD free convection with Joule heating and entropy generation inside an H-shaped hollow structure

In this research, a free convective flow of water inside an H-shaped hollow structure which is subjected to the existence of an exterior magnetic field and Joule heating is computationally investigated. The structure's right and left upright surfaces are maintained at invariant ambient thermal condition, while the top and bottom-most surfaces of the structure are in adiabatic condition. The rest of the inner walls are heated isothermally. Computational analysis is carried out for different configurations of the chamber by solving Navier-Stokes and heat energy equations via the finite element approach. Parametric computations are conducted by varying Hartmann numbers (0 ≤ Ha ≤ 20), Rayleigh numbers (103 ≤ Ra ≤ 106), width of the vertical sections (0.2 ≤ d/L ≤ 0.4, where L denotes the structure's reference dimension), and thickness of the horizontal middle section (0.2 ≤ t/L ≤ 0.4). To find out the impact of the governing parameters on thermal performance for different configurations, the mean Nusselt number along the hot walls, mean temperature of fluid, overall entropy generation, and thermal performance criterion are assessed. In addition, the variations in fluid motion and thermal patterns are reported in terms of streamlines, isotherms, and heatlines. With a larger mean Nusselt number and smaller thermal performance criterion, better heat transmission performance is found for thicker horizontal middle section and wider vertical sections. The maximum reduction in thermal performance criterion is found to be 87.8 % for increasing the width of the vertical sections. However, in the cases of Ha and d/L, there is an interesting transition in Nusselt number noticed for different Rayleigh numbers.

Dynamics of non-Newtonian methanol conveying aluminium alloy over a rotating disc: consideration of variable nanoparticle radius and inter-particle spacing

The advancement of non-Newtonian nanofluid innovation is a crucial area of research for physicists, mathematicians, manufacturers, and materials scientists. In engineering and industries, the fluid velocity caused by rotating device and nanofluid has a lot of applications such as refrigerators, chips, heat ex-changers, hybrid mechanical motors, food development, and so on. Due to the tremendous usage of the non-Newtonian nanofluid, the originality of the current study is to explore the influence of nanoparticle radii and inter-particle spacing effects on the flow characteristics of Casson methanol-based aluminium alloy (AA7072) nanofluid through a rotating disc with Joule heating and magnetic dipole. The present problem is modeled in the form of partial differential equations (PDEs), and these PDEs are converted into ordinary differential equations with the help of suitable similarity transformations. The analytical solution to the current modeled problem has been obtained by using the homotopy analysis method (HAM) and numerical solutions are obtained by employing Runge-Kutta-Fehlberg method along with shooting technique. The main purpose of the present research work is to analyze the behavior of the velocity and temperature of the nanofluid for small and large radius of the aluminium alloy (AA7072) nanoparticles and inter-particle spacing. The radial and tangential velocities are enhanced due to rising ferro-hydrodynamic interaction parameter and the skin friction force for radial and tangential directions are enhanced 10.51% and 2.16% whenh= 0.5. Also, the heat transfer rate is reduced 18.71% and 16.70% whenh= 0.5% andRp= 1.5. In fact, the present results are compared with the published results and they met good agreement.

Stretchable and Transparent Heaters Based on Hydrophobic Ionogels with Superior Moisture Insensitivity

Flexible and stretchable transparent heaters (THs) have been widely used in various applications, including deicing and defogging of flexible screens as well as thermotherapy pads. Ionic THs based on ionogels have emerged as a promising alternative to conventional electronic THs due to their unique advantages in terms of transparency-conductance conflict, uniform heating, and interfacial adhesion. However, the commonly used hydrophilic ionogels inevitably introduce a moisture-sensitive issue. In this work, we present a stretchable and transparent hydrophobic ionogel-based heater that utilizes ionic current-induced Joule heating under high-frequency alternating current. This ionogel-based TH exhibits exceptional multifunctional properties with low hysteresis, a fracture strain of 840%, transmittance of 93%, conductivity of 0.062 S m-1, temperature resistance up to 165 °C, voltage resistance up to 120 V, heating rate of 0.1 °C s-1, steady-state temperature at 115 °C, and uniform heating even when bent or stretched (up to 200%). Furthermore, it maintains its heating performance when it is directly exposed to water. This hydrophobic ionogel-based TH expands the range of materials available for ionic THs and paves the way for their practical applications.

Statistical computation for heat and mass transfers of water-based nanofluids containing Cu, Al2O3, and TiO2 nanoparticles over a curved surface

Nanofluid is a specially crafted fluid comprising a pure fluid with dispersed nanometer-sized particles. Incorporation these nanoparticles into pure fluid results in a fluid with improved thermal properties in comparison of pure fluid. The enhanced properties of nanofluids make them highly sought after, in diverse applications, consisting of coolant of devices, heat exchangers, and thermal solar systems. In this study hybrid nanofluid consisting of copper, alumina and titanium nanoparticles on a curved sheet has investigated with impact of chemical reactivity, magnetic field and Joule heating. The leading equations have converted to normal equations by using appropriate set of variables and has then evaluated by homotopy analysis method. The outcomes are shown through Figures and Tables and are discussed physically. It has revealed in this study that Cu-nanofluid flow has augmented velocity, temperature, and volume fraction distributions than those of Al2O3-nanofluid and TiO2-nanofluid. Also, the Cu-nanofluid flow has higher heat and mass transfer rates than those of Al2O3-nanofluid and TiO2-nanofluid.

Tailoring Interfaces of All-Carbon Electromagnetic Interference Shielding Materials for Boosting Comprehensive Performance

Electromagnetic interference (EMI) shielding materials with lightweight, high shielding effectiveness, excellent chemical stability, especially minimized secondary electromagnetic pollution, are urgently desired for integrated electronic systems operating in harsh working environments. Here in this study, by systematically engineering and matching the interfacial properties of carbon-based membrane materials, i.e., graphite paper, whisker carbon nanotube paper (WCNT paper), carbon nanotube film (CNT film), bucky paper (BP), and carbon cloth (CC) with three-dimensional (3D) porous carbon nanotube sponge (CNTS), we successfully constructed a series of multifunctional all-carbon EMI shielding materials, which exhibit excellent average shielding effectiveness of over 90 dB with a thickness of about 1 mm and dramatically minimized secondary electromagnetic reflection. Moreover, benefiting from the all-carbon nature and engineered interfaces, our CMC materials also exhibit excellent photothermal and Joule heating performances. These results not only provide guidance for designing advanced multifunctional all-carbon EMI shielding materials but also shed light on the hidden mechanism between interfaces and performances of composite materials.

Entropy generation for exact irreversibility analysis in the MHD channel flow of Williamson fluid with combined convective-radiative boundary conditions

The scrutinization of entropy optimization in the various flow mechanisms of non-Newtonian fluids with heat transfer has been incredibly enhanced. Through the investigation of irreversibility sources in the steady flow of a non-Newtonian Willaimson fluid, an analysis of entropy generation is carried out in this current work. The current study has an essential aspect of investigating the heat transfer mechanism with flow phenomenon by considering convective-radiative boundary conditions. A horizontal MHD channel is assumed with two parallel plates to develop a mathematical model for the flow phenomenon by considering the variable viscosity of the fluid. The contribution of physical impacts of thermal radiation, Joule heating, and viscous dissipation is interpolated in the constitutive energy equation. The complete flow of the current analysis is established in the form of ordinary differential equations which further take the form of the dimensionless system through the contribution of the similarity variables. A graphical scrutinization of the physical features of the flow phenomenon in relation to the pertinent parameters is proposed. This study reveals that the higher magnitude of radiation parameter and Brinkman number dominates the system's entropy. Moreover, the temperature distribution experiences an increasing mechanism with improved conduction-radiation parameter at the lower plate.

Enhanced heat transfer analysis on Ag-Al[Formula: see text]O[Formula: see text]/water hybrid magneto-convective nanoflow

The primary goal of this investigation is to examine the heat and flow characteristics of a hybrid nanofluid consisting of silver (Ag) and aluminum oxide (Al[Formula: see text]O[Formula: see text] nanoparticles over an unsteady radially stretching sheet embedded in porous medium. The investigation is conducted under the influence of several key parameters, namely joule heating, viscous dissipation, porous, slip, and suction. The technique of similarity transformations is used to transform the governing system of PDEs into nonlinear ODEs and the bvp4c solver is used to solve them numerically. The present study examines the influence of sphere and platelet shape nanoparticles on the temperature and velocity profiles. The outcomes are discussed through graphs and tables. A rise in the porous, slip, and suction parameters makes the velocity profile decrease gradually. The temperature escalates when Biot number, magnetic parameter, and Eckert number increase. As compared to sphere shapes, platelet-shaped nanoparticles exhibit the greatest heat transfer and flow. Results reveal that by using Ag-Al[Formula: see text]O[Formula: see text]/H[Formula: see text]O hybrid nanofluid with a volume fraction of 5%, the heat transfer enhancement of platelet shape nanoparticles increased by 11.88% than sphere-shaped nanoparticles. Overall, the platelet shape of nanoparticles offers distinctive advantages in various engineering applications, primarily due to their large surface area, anisotropic properties, and tunable surface chemistry. These properties make them versatile tools for improving the performance of materials and systems in engineering fields. The findings can contribute to the design and optimization of nanofluid-based systems in various engineering applications, such as heat exchangers, microfluidics, and energy conversion devices.

Thermal performance of Joule heating in radiative Eyring-Powell nanofluid with Arrhenius activation energy and gyrotactic motile microorganisms

Background

Bioconvection is the term for macroscopic convection of particles accompanied by a variable density gradient and a cluster of swimming microorganisms. The accumulation of gyrotactic microbes in the nanoparticles is important to exaggerate the thermal efficacy of various structures for instance, germs powered micro-churns, microbial fuel cubicles, micro-fluidics policies, and chip-designed micro plans like bio-microstructures.

Purpose

Here approach in the current effort is to present an innovative study of bio-convection owing to gyrotactic microbes in a nanofluid comprising non-uniform heat source/sink, space and temperature-dependent viscosity and Joule dissipation. The physical constraints such as convective-surface and new mass flux conditions are examined for 3D Eyring-Powell magneto-radiative nanofluid via porous stretched sheet.

Method

ology: Over suitable similarity alterations, the related non-linear flow, temperature, and concentration phenomena, equations are altered into non-linear equations. By combining the shooting methodology with the Runge-Kutta fourth-order technique is applied to get numerical solutions. A thorough investigation for the impact of important non-dimensional thermophysical parameters regulating flow characteristics is carried out.

Motivation

Lots of the studies on nanofluids realize their performance therefore that they can be exploited where conventional heat transport development is paramount as in numerous engineering uses, micro-electronics, transportation in addition to foodstuff and bio-medicine. The gyrotactic microbes flow in nanofluids has attained great devotion amongst researchers and the scientist community because of its works in numerous areas of bio-technology. The benefits of counting nanoparticles in mobile microbe's deferral can be established in micro-scale involvement and stability of nanofluid.

Significant results

For a few chosen parameters, the computed results for friction factor and transport for motile microorganism values are shown. The computed numerical results for parameters of engineering interest are given using tables. Furthermore, the recent solutions are stable with the former stated results and excellent association is found. The temperature of the fluid exaggerates for higher values of thermo-Biot and radiation parameter; however, Peclet and bio-convective Lewis's factor decay the motile microorganisms' field of Eyring-Powell fluid. The concentration field also enhances the activation energy parameter.

Ultralow Electric Current-Assisted Magnetization Switching due to Thermally Engineered Magnetic Anisotropy

Control of magnetic anisotropy in thin films with perpendicular magnetic anisotropy is of paramount importance for the development of spintronics with ultralow-energy consumption and high density. Traditional magnetoelectric heterostructures utilized the synergistic effect of piezoelectricity and magnetostriction to realize the electric field control of magnetic anisotropy, resulting in additional fabrication and modulation processes and a complicated device architecture. Here, we have systematically investigated the electric current tuning of the magnetic properties of the metallic NiCo2O4 film with intrinsic perpendicular magnetic anisotropy. Ferrimagnetic-to-paramagnetic phase transition has been induced through Joule heating, resulting in a rapid decrease of both magnetic coercivity and moment. An ultralow current density of 2.5 × 104 A/cm2, which is 2 to 3 orders magnitude lower than that of conventional spin transfer torque devices, has been verified to be effective for the control of the magnetic anisotropy of NiCo2O4. Successful triggering of magnetic switching has been realized through the application of a current pulse. These findings provide new perspectives toward the electric control of magnetic anisotropy and design of spintronics with an ultralow driving current density.

Heat-Assisted Magnetization Switching in Flexible Spin-Orbit Torque Devices

Heat-assisted magnetic anisotropy engineering has been successfully used in selective magnetic writing and microwave amplification due to a large interfacial thermal resistance between the MgO barrier and the adjacent ferromagnetic layers. However, in spin-orbit torque devices, the writing current does not flow through the tunnel barrier, resulting in a negligible heating effect due to efficient heat dissipation. Here, we report a dramatically reduced switching current density of ∼2.59 MA/cm2 in flexible spin-orbit torque heterostructures, indicating a 98% decrease in writing energy consumption compared with that on a silicon substrate. The reduced driving current density is enabled by the dramatically decreased magnetic anisotropy due to Joule dissipation and the lower thermal conductivity of the flexible substrate. The large magnetic anisotropy could be fully recovered after the impulse, indicating retained high stability. These results pave the way for flexible spintronics with the otherwise incompatible advantages of low power consumption and high stability.

Revealing the Orbital Interactions between Dissimilar Metal Sites during Oxygen Reduction Process

A FeCo/DA@NC catalyst with the well-defined FeCoN6 moiety is customized through a novel and ultrafast Joule heating technique. This catalyst demonstrates superior oxygen reduction reaction activity and stability in an alkaline environment. The power density and charge-discharge cycling of znic-air batteries driven by FeCo/DA@NC also surpass those of Pt/C catalyst. The source of the excellent oxygen reduction reaction activity of FeCo/DA@NC originates from the significantly changed charge environment and 3d orbital spin state. These not only improve the bonding strength between active sites and oxygen-containing intermediates, but also provide spare reaction sites for oxygen-containing intermediates. Moreover, various in situ detection techniques reveal that the rate-determining step in the four-electron oxygen reduction reaction is *O2 protonation. This work provides strong support for the precise design and rapid preparation of bimetallic catalysts and opens up new ideas for understanding orbital interactions during oxygen reduction reactions.

Recyclable Multifunctional Nanocomposites Based on Carbon Nanotube Reinforced Vitrimers with Shape Memory and Joule Heating Capabilities

The present study focuses on the multifunctional capabilities of carbon nanotube (CNT)-reinforced vitrimers. More specifically, the thermomechanical properties, the Joule effect heating capabilities, the electrical conductivity, the shape memory, and the chemical recycling capacity are explored as a function of the CNT content and the NH2/epoxy ratio. It is observed that the electrical conductivity increases with the CNT content due to a higher number of electrical pathways, while the effect of the NH2/epoxy ratio is not as prevalent. Moreover, the Tg of the material decreases when increasing the NH2/epoxy ratio due to the lower cross-link density, whereas the effect of the CNTs is more complex, in some cases promoting a steric hindrance. The results of Joule heating tests prove the suitability of the proposed materials for resistive heating, reaching average temperatures above 200 °C when applying 100 V for the most electrically conductive samples. Shape memory behavior shows an outstanding shape fixity ratio in every case (around 100%) and a higher shape recovery ratio (95% for the best-tested condition) when decreasing the NH2/epoxy ratio and increasing the CNT content, as both hinder the rearrangement of the dynamic bonds. Finally, the results of the recyclability tests show the ability to regain the nanoreinforcement for their further use. Therefore, from a multifunctional analysis, it can be stated that the proposed materials present promising properties for a wide range of applications, such as Anti-icing and De-icing Systems (ADIS), Joule heating devices for comfort or thermotherapy, or self-deployable structures, among others.

Rapid High-Temperature Liquid Shock Synthesis of High-Entropy Alloys for Hydrogen Evolution Reaction

High-entropy-alloy nanoparticles (HEA-NPs) show great potential as electrocatalysts for water splitting, fuel cells, CO2 conversion, etc. However, fine-tuning the surface, morphology, structure, and crystal phase of HEA remains a great challenge. Here, the high-temperature liquid shock (HTLS) technique is applied to produce HEA-NPs, e.g., PtCoNiRuIr HEA-NPs, with tunable elemental components, ultrafine particle size, controlled crystal phases, and lattice strains. HTLS directly applied Joule heating on the liquid mixture of metal precursors, capping agents, and reducing agents, which is feasible for controlling the morphology and structure such as the atomic arrangement of the resulting products, thereby facilitating the rationally designed nanocatalysts. Impressively, the as-obtained PtCoNiRuIr HEA-NPs delivered superior activity and long-term stability for the hydrogen evolution reaction (HER), with low overpotentials at 10 mA cm-2 and 1 A cm-2 of only 18 and 408 mV, respectively, and 10000 CV stable cycles in 0.5 M H2SO4. Furthermore, in the near future, by combining the HTLS method with artificial intelligence (AI) and theoretical calculations, it is promising to provide an advanced platform for the high-throughput synthesis of HEA nanocatalysts with optimized performance for various energy applications, which is of great significance for achieving a carbon-neutral society with an effective and environmentally friendly energy system.

On-Chip Modification of Titanium Electrothermal Characteristics by Joule Heating: Application to Terahertz Microbolometer

This study demonstrates the conversion of metallic titanium (Ti) to titanium oxide just by conducting electrical current through Ti thin film in vacuum and increasing the temperature by Joule heating. This led to the improvement of electrical and thermal properties of a microbolometer. A microbolometer with an integrated Ti thermistor and heater width of 2.7 µm and a length of 50 µm was fabricated for the current study. Constant-voltage stresses were applied to the thermistor wire to observe the effect of the Joule heating on its properties. Thermistor resistance ~14 times the initial resistance was observed owing to the heating. A negative large temperature coefficient of resistance (TCR) of -0.32%/K was also observed owing to the treatment, leading to an improved responsivity of ~4.5 times from devices with untreated Ti thermistors. However, this does not improve the noise equivalent power (NEP), due to the increased flicker noise. Microstructural analyses with transmission electron microscopy (TEM), transmission electron diffraction (TED) and energy dispersive X-ray (EDX) confirm the formation of a titanium oxide (TiOx) semiconducting phase on the Ti phase (~85% purity) deposited initially, further to the heating. Formation of TiOx during annealing could minimize the narrow width effect, which we reported previously in thin metal wires, leading to enhancement of responsivity.

TDA/rGO@WS with Joule heat and photothermal synergistic effect: A promising adsorption material for all-weather recovery of viscous oil spills at sea

Oil spills are a global environmental protection challenge, and traditional adsorption materials have poor effect on low temperature and high viscosity marine oil spills. This article reports composite adsorption materials TDA/rGO@WS for viscous oil spills: loaded with rGO/TDA coating on a commercial biomass wood pulp sponge (WS), achieving Joule heating, photothermal effect and hydrophobic modification. The results showed that the TDA/rGO@WS has good photothermal conversion ability and Joule heating ability, and the temperature increased to 83.7 °C and 148 °C, respectively, under simulated solar irradiation and additional voltage at room temperature. The efficiency of adsorption at a low temperature of 5 °C increased by 22.41% at 1 sun and by 51.53% at 10 V. Temperature effectively reduced the viscosity of the offshore oil spill and ensures the efficient adsorption of oil spills at low temperatures promoted. The TDA/rGO@WS also showed good hydrophobicity (WCA=129°), excellent efficiency of water-oil separation (99.53%) and good adsorption capacity (9.4-13.68 g/g) for marine fuel oils. TDA/rGO@WS effectively solves the problem of cleaning up high-viscosity oil spills from ships in winter and polar waters, and proposes a new strategy for all-weather efficient treatment of oil spills at sea.

Silver nanowire-infused carbon aerogel: A multifunctional nanocellulose-derived material for personal thermal management

Personal thermal management (PTM) textiles for outdoor activities have become increasingly important for addressing energy consumption and thermal comfortable. Cellulose nanofiber (CNF) aerogels have emerged as promising candidates for PTM due to the eco-friendliness, lightweight, and low thermal conductivity. However, the singular insulation capability may not be sufficient to accommodate the diverse and harsh outdoor conditions. Herein, we carbonized CNF-based aerogel to fabricate anisotropic carbon aerogels, and then incorporated silver nanowires (AgNWs) upon onside to fabricate the dual-function AgNWs/carbon aerogel. The resulting material inherits high porosity (99.3 %), high surface area (503.2 m2/g), low density (7.08 mg/cm3), and low thermal conductivity (18.2 mW·m-1·k-1 in the axial direction) to act as an ideal thermal insulator. The AgNWs coating side demonstrates low IR-emissivity (17.6 % at 7-14 μm) and the carbon aerogel side has high solar absorptivity (91.97 %). Moreover, the AgNWs/carbon aerogel shows Joule heating performance (∆T = 44.5 °C within 3 min at 5 V). The multi-heating modes enabling self-adaptable thermal comfortable under various harsh environment. Additionally, the material's breathability, permeability, and electromagnetic shielding characteristics also make it suitable candidate for advanced wearable textiles for PTM.

Multifunctional Flexible MXene/AgNW Composite Thin Film with Ultrahigh Conductivity Enabled by a Sandwich-Structured Assembly Strategy

Flexible composite films have attracted considerable attention due to great potential for healthcare, telecommunication, and aerospace. However, it is still challenging to achieve high conductivity and multifunctional integration, mainly due to poorly designed composite structures of these films. Herein, a novel sandwich-structured assembly strategy is proposed to fabricate flexible composite thin films made of Ag nanowire (AgNW) core and MXene layers by combination of spray coating and vacuum filtration process. In this case, ultrathin MXene layers play crucial roles in constructing compact composite structures strongly anchored to substrate with extensive hydrogen-bonding interactions. The resultant sandwich-structured MXene/AgNW composite thin films (SMAFs) exhibit ultrahigh electrical conductivity (up to 27193 S cm-1 ), resulting in exceptional electromagnetic interference shielding effectiveness of 16 223.3 dB cm2 g-1 and impressive Joule heating performance with rapid heating rate of 10.4 °C s-1 . Moreover, the uniform SMAFs can also be facilely cut into kirigami-patterned interconnects, which indicate superior strain-insensitive conductance even after long-term exposure to extreme temperatures. The demonstrated strategy offers a significant paradigm to construct multifunctional composite thin films for next-generation integrated flexible electronics with practical applications.

Hydrated alginate polysaccharide fabrics grafted with sliver nanocrystals for wearable thermal and health management

The creation of functional components with precise chemistries on carbohydrate polymers is of great significance for future wearable biomedicine and health management. Among various carbohydrate polymers, marine polysaccharide featured with antimicrobial, biodegradable and biocompatible properties is an ideal platform while the water-swelling nature makes it difficult to form stable interface. Here, well-dispersed silver nanoparticles have been in-situ assembled on hydrated alginate fabric (AF), involving chemical absorption of Ag ions and in-situ reduction of conductive Ag layer. Owing to the stable complex formed between Ag ions and carboxyl groups, the Ag-grafted AF exhibits superior Joule heating capability, including low operating voltage (1-3 V), high saturation temperature (63 °C), rapid response time (25 s) and outstanding durability against harsh conditions. Furthermore, the Ag-grafted AF demonstrates noticeable inhibition against E. coli and S. aureus as compared with the pristine AF. This work provides a rational strategy for the functionalization of hydrated polysaccharide and enables wearable thermotherapy devices for human health management.

One-Step Method for Fabricating Janus Aramid Nanofiber/MXene Nanocomposite Films with Improved Joule Heating and Thermal Camouflage Properties

The integration of ultraflexible and mechanically robust films with electric heaters and camouflage technology provides a promising platform for the development of wearable devices, especially for aerospace and military applications. Herein, we present a facile and efficient one-step vacuum-assisted filtration method for fabricating Janus films based on aramid nanofibers (ANF) and Ti3C2Tx (MXene). The ANF/MXene nanocomposite film exhibits remarkable properties, including high conductivity (23809.5 S/m), excellent mechanical strength (102.54 MPa), and outstanding thermal stability (575 °C). Most notably, the Janus ANF/MXene composite film demonstrates superior Joule heating performance with a low driving voltage (1-5 V), high heating temperature (30-276 °C), and rapid response time (within 5 s). Additionally, the film exhibits effective thermal camouflage (72 °C for objects with temperatures above 163 °C) and excellent electromagnetic interference shielding properties (SSE/t = 32475.6 dB cm2/g). These results demonstrate that Janus ANF/MXene films possess a unique combination of thermal camouflage, Joule heating, and electromagnetic interference shielding properties, making them highly promising for wearable devices, high-performance electrical heating, infrared stealth, and security protection applications.

Ca-Based Layered Double Hydroxides for Environmentally Sustainable Carbon Capture

The process of carbon dioxide capture typically requires a large amount of energy for the separation of carbon dioxide from other gases, which has been a major barrier to the widespread deployment of carbon capture technologies. Innovation of carbon dioxide adsorbents is herein vital for the attainment of a sustainable carbon capture process. In this study, we investigated the electrified synthesis and rejuvenation of calcium-based layered double hydroxides (Ca-based LDHs) as solid adsorbents for CO2. We discovered that the particle morphology and phase purity of the LDHs, along with the presence of secondary phases, can be controlled by tuning the current density during electrodeposition on a porous carbon substrate. The change in phase composition during carbonation and calcination was investigated to unveil the effect of different intercalated anions on the surface basicity and thermal stability of Ca-based LDHs. By decoupling the adsorption of water and CO2, we showed that the adsorbed water largely promoted CO2 adsorption, most likely through a sequential dissolution and reaction pathway. A carbon capture capacity of 4.3 ± 0.5 mmol/g was measured at 30 °C and relative humidity of 40% using 10 vol % CO2 in nitrogen as the feed stream. After CO2 capture occurred, the thermal regeneration step was carried out by directly passing an electric current through the conductive carbon substrate, known as the Joule-heating effect. CO2 was found to start desorbing from the Ca-based LDHs at a temperature as low as 220 °C as opposed to the temperature above 700 °C required for calcium carbonate that forms as part of the Ca-looping capture process. Finally, we evaluated the cumulative energy demand and environmental impact of the LDH-based capture process using a life cycle assessment. We identified the most environmentally concerning step in the process and concluded that the postcombustion CO2 capture using LDH could be advantageous compared with existing technologies.

Numerical simulation of variable density and magnetohydrodynamics effects on heat generating and dissipating Williamson Sakiadis flow in a porous space: Impact of solar radiation and Joule heating

This study is confined to the numerical evaluation of variable density and magnetohydrodynamics influence on Williamson Sakiadis flow in a porous space. In this study, Joule heating, dissipation, heat generation effect on optically dense gray fluid is encountered. The inclined moving surface as flow geometry is considered to induce the fluid flow. A proposed phenomenon is given a mathematical structure in partial differential equations form. These partial differential equations are then made dimensionless using dimensionless variables. The obtained dimensionless model in partial differential equations is then changed to ordinary differential equations via stream function formulation. A set of transformed equations has been solved with bvp4c solver. The numerical fallout of velocity field, temperature field, skin friction, and heat transfer rate are illustrated in graphs and tables with flow parametric variations. Conclusion is drawn that mounting values of density variation parameter confirm the reduction in velocity field and augmentation in temperature of the fluid. When Williamson fluid parameter enhances, both fluid velocity and temperature are rising correspondingly. Growing magnitudes of the magnetic number, radiation parameter, heat generation, and Eckert number rise the temperature of the fluid. A rise in a porous medium parameter weakens the fluid velocity. Skin friction is reducing as radiation parameter and density variation parameter are increased. The present solutions are compared to those that have already been published in order to validate the current model. The comparison leads to the conclusion that the two outcomes are in excellent agreement, endorsing the veracity of the current answers.

Thermal Management Enables Stable Perovskite Nanocrystal Light-Emitting Diodes with Novel Hole Transport Material

The severely insufficient operational lifetime of perovskite light-emitting diodes (LEDs) is incompatible with the rapidly increasing external quantum efficiency, even as it approaches the theoretical limit, thereby significantly impeding the commercialization of perovskite LEDs. In addition, Joule heating induces ion migration and surface defects, degrades the photoluminescence quantum yield and other optoelectronic properties of perovskite films, and induces the crystallization of charge transport layers with low glass transition temperatures, resulting in LED degradation under continuous operation. Here, a novel thermally crosslinked hole transport material, poly(FCA60 -co-BFCA20 -co-VFCA20 ) (poly-FBV), with temperature-dependent hole mobility is designed, which is advantageous for balancing the charge injection of the LEDs and limiting the generation of Joule heating. The optimised CsPbI3 perovskite nanocrystal LEDs with poly-FBV realise approximately a 2-fold external quantum efficiency increase over the LED with commercial hole transport layer poly(4-butyl-phenyl-diphenyl-amine) (poly-TPD), owing to the balanced carrier injection and suppressed exciton quenching. Moreover, because of the Joule heating control provided by the novel crosslinked hole transport material, the LED utilising crosslinked poly-FBV has a 150-fold longer operating lifetime (490 min) than that utilizing poly-TPD (3.3 min). The study opens a new avenue for the use of PNC LEDs in commercial semiconductor optoelectronic devices.

Numerical analysis of radiative hybrid nanomaterials flow across a permeable curved surface with inertial and Joule heating characteristics

The water-based Cu and CoFe2O4 hybrid nano liquid flow across a permeable curved sheet under the consequences of inertial and Lorentz forces has been reported in this analysis. The Joule heating and Darcy Forchheimer effects on fluid flow have been also examined. In the presence of copper (Cu) and cobalt iron oxide (CoFe2O4) nanoparticles, the hybrid nano liquid is synthesized. Radiation and heat source features are additionally incorporated to perform thermodynamics analysis in detail. The second law of thermodynamics is employed in order to estimate the overall generation of entropy. The nonlinear system of PDEs (partial differential equations) is transformed into a dimensionally-free set of ODEs (ordinary differential equations) by employing a similarity framework. The Mathematica built in package ND Solve method is applied to compute the resulting set of nonlinear differential equations numerically. Along with the velocity, and temperature profiles, skin friction and Nusselt number are also computed. Figures and tables illustrate the effects of flow factors on important profiles. Evidently, the outcomes reveal that hybrid nanofluid (Cu + CoFe2O4+H2O) is more progressive than nanofluid (Cu + H2O) and base fluid (H2O) in thermal phenomena. Furthermore, the velocity profile is improved with the greater values of curvature parameter, while the inverse trend is observed against the magnetic parameters. Also, the velocity and energy distribution of hybrid nano-liquid flow boosts with the inclusion of Cu and CoFe2O4 nanoparticles into the base fluid. Velocity distribution diminishes with the increment of volume friction. For high values of inertial factor, skin friction improve while velocity and Nusselt number declines.

Temperature-dependent dynamics of electrokinetic conservative and reactive transport in porous media: A model-based analysis

Electrokinetic techniques employ direct current electric fields to enhance the transport of amendments in low permeability porous media and have been demonstrated effective for in situ remediation of both organic contaminants and heavy metals. The application of electric potential gradients give rise to coupled chemical, hydraulic and electric fluxes, which are at the basis of the main transport mechanisms: electromigration and electroosmosis. Previous research has highlighted the significant impacts of charge interactions and fluid composition, including temperature-dependent properties such as electrolyte conductivity and density, on these transport phenomena. However, current models of electrokinetic applications often assume isothermal conditions and overlook the production of heat resulting from Joule heating. This study provides a detailed model-based investigation, systematically exploring the effects of temperature on electrokinetic conservative and reactive transport in porous media. By incorporating temperature-dependent material properties and progressively investigating the impact of temperature on each transport mechanism, we analyze the effects of temperature variations in both 1D and 2D systems. The study reveals how temperature dynamically influences the physical, chemical and electrostatic processes controlling electrokinetic transport. A temperature increase results in a higher speed of amendments delivery by both electromigration and electroosmosis and increases the kinetics of degradation reactions. The simulations also reveal a feedback mechanism in which higher aqueous conductivity results in increased Joule heating, leading to a faster temperature rise and, subsequently, to higher electrolyte conductivity. Finally, we estimate the electric energy requirements of the system at varying temperatures and show how these changes impact the rate of contaminant removal.

Solvent Welding-Based Methods Gently and Effectively Enhance the Conductivity of a Silver Nanowire Network

To enhance the conductivity of a silver nanowire (Ag NW) network, a facile solvent welding method was developed. Soaking a Ag NW network in ethylene glycol (EG) or alcohol for less than 15 min decreased the resistance about 70%. Further combined solvent processing via a plasmonic welding approach decreased the resistance about 85%. This was achieved by simply exposing the EG-soaked Ag NW network to a low-power blue light (60 mW/cm2). Research results suggest that poly(vinylpyrrolidone) (PVP) dissolution by solvent brings nanowires into closer contact, and this reduced gap distance between nanowires enhances the plasmonic welding effect, hence further decreasing resistance. Aside from this dual combination of methods, a triple combination with Joule heating welding induced by applying a current to the Ag NW network decreased the resistance about 96%. Although conductivity was significantly enhanced, our results showed that the melting at Ag NW junctions was relatively negligible, which indicates that the enhancement in conductivity could be attributed to the removal of PVP layers. Moreover, the approaches were quite gentle so any potential damage to Ag NWs or polymer substrates by overheating (e.g., excessive Joule heating) was avoided entirely, making the approaches suitable for application in devices using heat-sensitive materials.

Melt-blown fiber felt for efficient all-weather recovery of viscous oil spills by Joule heating and photothermal effect

Adsorbents play a vital role in responding to marine oil spills, yet effectively cleaning up viscous oil spills remains a technical challenge. Herein, we present a superhydrophobic oil-adsorbing felt prepared using melt-blown technology and functionally enhanced with a photoelectric composite CNT/PANI coating for effectively cleaning up high-viscosity oil spills. By virtue of its superior solar/Joule heating ability and thermally conductive fiber network, p-CNT/PANI@PP notably reduced crude oil viscosity and enhanced the oil diffusion coefficient within pores. Leveraging primarily solar heating and supplemented by Joule heating, p-CNT/PANI@PP demonstrates an impressive in-situ adsorption rate of up to 560 g/h for ultra-high-viscosity crude oil (c.a. 138000 mPa·s), alongside an adsorption capacity of 15.57 g/g. This measure enables efficient viscosity reduction and continuous day-and-night recovery of viscous crude oil, addressing the challenges posed by seasonal fluctuations in seawater temperature and adverse weather conditions. Moreover, a conveyorized collector integrated with an oil-adsorbing felt realizes continuous recovery of viscous oil spills with speed control to tackle varying thicknesses of oil film. Given the top-down material design, superior functionality, and applicability to applications, this work provides a comprehensive and feasible solution to catastrophic large-area viscous oil spills.

Applications of electrically conductive membranes in water treatment via membrane distillation: Joule heating, membrane fouling/scaling/wetting mitigation and monitoring

Membrane distillation (MD) is a thermally driven separation process that is driven by phase change. The core of this technology is the hydrophobic microporous membrane that prevents mass transfer of the liquid while allowing the vapor phase to pass through the membrane's pores. Currently, MD is challenged by its high energy consumption and membrane degradation due to fouling, scaling and wetting. The use of electrically conductive membranes (ECMs) is a promising alternative method to overcome these challenges by inducing localized Joule heating, as well as mitigating and monitoring membrane fouling/scaling/wetting. The objective of this review is to consolidate recent advances in ECMs from the standpoint of conductive materials, membrane fabrication methodologies, and applications in MD processes. First, the mechanisms of ECMs-based MD processes are reviewed. Then the current trends in conductive materials and membrane fabrication methods are discussed. Thereafter, a comprehensive review of ECMs in MD applications is presented in terms of the different processes using Joule heating and various works related to membrane fouling, scaling, and wetting control and monitoring. Key insights in terms of energy consumption, economic viability and scalability are furnished to provide readers with a holistic perspective of the ECMs potential to achieve better performances and higher efficiencies in MD. Finally, we illustrate our perspectives on the innovative methods to address current challenges and provide insights for advancing new ECMs designs. Overall, this review sums up the current status of ECMs, looking at the wide range of conductive materials and array of fabrication methods used thus far, and putting into perspective strategies to deliver a more competitive ECMs-based MD process in water treatment.

Heat and mass transfer by stirring nanofluids with the presence of renewable solar rays, Joule heating, and entropy procreation

Renewable solar radiation is the foremost energy source because of its accessibility, natural replication, and sustainability in an environmentally safe manner. Here, researchers intended to inspect the heat and mass transfer via nanofluid transported on an inclined permeable expanded sheet in the presence of solar thermal radiation without any barrier. Mainly, the formation of non-recovery energy called entropy and Joule heating are also weighed. The guiding non-linear partial differential equations were transformed into systems of non-linear higher-order ordinary differential equations by felicitous similarity transformation. They are solved by the prevalent technique called the Homotopy Analysis Method, which is executed by the BVPh2.0 package in Mathematica 12.1 software. Comparisons with preceding published articles confirm the method's validity and accent its admirable uniformity. Afterward, the magnetic field interaction delays the mobility of nanofluid while increasing the magnitude of local skin friction and temperature distribution. By intensifying the thermal radiation parameter and Eckert number, the temperature and entropy production escalated. Furthermore, the heat transfer by convective surpasses that of conductive owing to the particles' Brownian motion. Thermophoresis established surplus tiny-particles concentration. Heat transfer from solar radiation in moving nanofluids has been applicable for cooking, heating water, and producing electricity.

Black Phosphorus Field-Effect Transistors with Improved Contact via Localized Joule Heating

Two-dimensional (2D) black phosphorus (BP) is considered an ideal building block for field-effect transistors (FETs) owing to its unique structure and intriguing properties. To achieve high-performance BP-FETs, it is essential to establish a reliable and low-resistance contact between the BP and the electrodes. In this study, we employed a localized Joule heating method to improve the contact between the 2D BP and gold electrodes, resulting in enhanced BP-FET performance. Upon applying a sufficiently large source-drain voltage, the zero-bias conductance of the device increased by approximately five orders of magnitude, and the linearity of the current-voltage curves was also enhanced. This contact improvement can be attributed to the formation of gold phosphide at the interface of the BP and the gold electrodes owing to current-generated localized Joule heat. The fabricated BP-FET demonstrated a high on/off ratio of 4850 and an on-state conductance per unit channel width of 1.25 μS μm-1, significantly surpassing those of the BP-FETs without electrical annealing. These findings offer a method to achieve a low-resistance BP/metal contact for developing high-performance BP-based electronic devices.

Dual Protective Porous Ti3 C2 Tx MXene/Polyimide Composite Film for Thermal Insulation and Electromagnetic Interference Shielding

The thriving 5G communication technology leads to the high demand for EMI shielding materials and thermal management materials. Particularly, portable thermal-sensitive electronic devices have more stringent requirements for thermal insulation performances. In most cases, ultrathin EMI shielding materials integrated with ultralow thermal conductivity are not easy to be achieved. To overcome this obstacle, dual protective porous composite films based on Ti3 C2 Tx MXene and polyimide are fabricated by sacrificing polymethyl methacrylate (PMMA) templates. By optimizing the contact thermal resistance and Kapitza resistance, the composite film presents superior thermal insulation performances with a thermal conductivity of 0.0136 W m-1 K-1 . Moreover, the hybrid porous film maintains superior EMI shielding effectiveness of 63.0 dB and high SSE/t of 31651.2 dB cm2 g-1 . Nevertheless, the excellent active and passive heating ability based on Joule heating and photothermal conversion makes the composite film an ideal portable material for thermal management. This work sheds light on designing thermal management materials and EMI shielding materials for cutting-edge electronic devices.

Effect of Atmospheric Temperature on Epoxy Coating Reinforced with Carbon Nanotubes for De-Icing on Road Systems

Traffic accidents caused by road icing are a serious global problem, and conventional de-icing methods like spraying chemicals have several limitations, including excessive manpower management, road damage, and environmental pollution. In this study, the carbon nanotubes reinforced de-icing coating for the road system with a self-heating function was developed as part of the development of a new system to prevent accidents caused by road icing. The electrical characteristics of the fabricated coating were analyzed, and the carbon nanotube coating heating performance experiment was conducted to measure the temperature increments by applying a voltage to the coating at a sub-zero temperature using an environmental chamber. In addition, the coating was installed on the road pavement and the applicability was investigated through a heating test in winter. As a result of the experiment, the coating made with the higher carbon nanotube concentration presented higher heating owing to its higher electrical conductivity. In addition, the coating showed sufficient heating performance, although the maximum temperature by Joule heating decreased for the entire coating at sub-zero temperatures. Finally, field tests demonstrated the potential of electrically conductive coatings for de-icing applications.

Unsteady mhd flow of tangent hyperbolic liquid past a vertical porous plate plate

The analysis in this communication addresses the unsteady MHD flow of tangent hyperbolic liquid through a vertical plate. The model on mass and heat transport is set up with Joule heating, heat generation, viscous dissipation, thermal radiation, chemical reaction and Soret-Dufour in the form of partial differential equations (PDEs). The PDEs are simplified into a dimensionless PDEs by utilizing a suitable quantities. The simplified equations are solved by utilizing the spectral relaxation method (SRM). The outcomes shows that increase in the Weissenberg and the magnetic field degenerates the velocity profile. The thermal radiation is found to elevate the velocity and temperature profiles as its values increases. The impact of Soret and Dufour on the flow is found to alternate each other. The computational outcomes for concentration, temperature and velocity are illustrated graphically for all encountered flow parameters. The present outcomes are compared with previous outcomes and are found to correlate.

Flexible Basalt Fiber/Aramid Nanofiber/Carbon Nanotube Electromagnetic Shielding Paper with Outstanding Environmental Stability and Joule Heating Performance

In the field of electromagnetic shielding, it has become an important trend to manufacture thinner and better-performing electromagnetic interference (EMI) shielding materials. However, EMI shielding materials that are recyclable and resistant to extreme environments are of great significance for sustainable development and expanding their application areas. In this study, a composite paper with a "rebar-concrete" layered structure through the vacuum-assisted filtration approach by utilizing basalt fibers (BF) and aramid nanofibers (ANFs) with excellent temperature resistance and multiwalled carbon nanotubes with high electrical conductivity was prepared. The composite paper not only delivers a high electrical conductivity of 15.9 S cm^-1 and a high electromagnetic interference shielding efficiency (EMI SE) of 24.6 dB but also exhibits a high specific shielding efficiency (SSE/t) of 12,504 dB cm² g^-1 at a thickness of 48 μm. Thanks to the excellent thermal stability of basalt fibers and aramid nanofibers, the composite paper exhibits long-term stable EMI shielding performance and structural integrity in various extreme environments, including fire, high/low temperature (-196 to 300 °C), and acid-base corrosion. Furthermore, the BF/ANF/CNT composite paper also shows excellent Joule heating performance, rapid electrothermal response, and good temperature controllability. Based on these excellent properties, the BF/ANF/CNT composite paper shows tremendous potential for practical applications to meet the requirements of various extreme environments.

Multifunctional Conductive Material Based on Intelligent Porous Paper Used in Conjunction with a Vitrimer for Electromagnetic Shielding, Sensing, Joule Heating, and Antibacterial Properties

With the continuous improvement of living standards and advancements in science and technology, composite materials with multiple functionalities are gaining high practical value in modern society. In this paper, we present a multifunctional conductive paper-based composite with electromagnetic (EMI) shielding, sensing, Joule heating, and antimicrobial properties. The composite is prepared by growing metallic silver nanoparticles inside the cellulose paper (CP) modified with polydopamine (PDA). The resulting CP@PDA@Ag (CPPA) composite has high conductivity and EMI shielding properties. Furthermore, CPPA composites demonstrate exceptional sensing, Joule heating, and antimicrobial properties. In addition, Vitrimer, a polymer with excellent cross-linked network structure, is introduced into CPPA composites to obtain CPPA-V intelligent electromagnetic shielding materials with shape memory function. These excellent properties show that the prepared multifunctional intelligent composite has exceptional EMI shielding, sensing, Joule heating, and antibacterial and shape memory properties. In short, this multifunctional intelligent composite material has great application prospects in flexible wearable electronics.

Electrical Resistivity of 3D-Printed Polymer Elements

During this study, the resistivity of electrically conductive structures 3D-printed via fused filament fabrication (FFF) was investigated. Electrical resistivity characterisation was performed on various structural levels of the whole 3D-printed body, starting from the single traxel (3D-printed single track element), continuing with monolayer and multilayer formation, finalising with hybrid structures of a basic nonconductive polymer and an electrically conductive one. Two commercial conductive materials were studied: Proto-Pasta and Koltron G1. It was determined that the geometry and resistivity of a single traxel influenced the resistivity of all subsequent structural elements of the printed body and affected its electrical anisotropy. In addition, the results showed that thermal postprocessing (annealing) affected the resistivity of a standalone extruded fibre (extruded filament through a printer nozzle in freefall) and traxel. The effect of Joule heating and piezoresistive properties of hybrid structures with imprinted conductive elements made from Koltron G1 were investigated. Results revealed good thermal stability within 70 °C and considerable piezoresistive response with a gauge factor of 15-25 at both low 0.1% and medium 1.5% elongations, indicating the potential of such structures for use as a heat element and strain gauge sensor in applications involving stiff materials and low elongations.

Mathematical analysis of radius and length of CNTs on flow of nanofluid over surface with variable viscosity and joule heating

The transfer of heat is a phenomenon that is significant in a variety of contexts due to the different ways in which it may be utilized in industrial settings. To increase the rate at which heat is transferred, carbon nanotubes (CNTs), which can either be single-wall or multi-walled, are suspended in base fluids, and the resulting mixture is referred to as a "nanofluid. This study looks at how heat transfers through nanofluids that are suspended in carbon nanotubes with different lengths and radii over a stretching surface. It also looks at how changing viscosity and joule heating affect motion. Water is taken as base fluid. This study looks at both carbon nanotubes with one wall and those with more than one. The flow is governed by a series of partial differential equations, which, to control the flow, are transformed into a series of nonlinear ordinary differential equations. Similarity transformation is used to convert the obtained nonlinear ordinary differential equations and accompanying boundary conditions into a form that is dimensionless. To numerically solve the transformed equation, RK-4 with shooting method is used. Graphs and in-depth discussions are used to look at how velocity and temperature profiles are affected by the leading variables. The expression for skin friction and local Nusselt number are written down and graphs show how these two numbers change for different parameter values. The temperature profile goes down when the viscosity parameter goes down, but the velocity profile goes up. When the magnetic parameter goes up, the velocity profile f'(η), goes down, but the velocity profile g(η) and temperature θ(η) both go up at the same time. The rate of heat transfer increases with the addition of φ and S. When the suction parameter (S = 2.1) with 1% of φ is used, it is reported that rate of heat transfer increases by 1.135% for Single walled and 1.275% for Multi Walled carbon nanotubes. To determine whether or not the proposed numerical model is legitimate, a comparison is made between the current results and those that have previously been published.

High-Efficiency Recovery of Acetic Acid from Water Using Electroactive Gas-Stripping Membranes

Recovery of carbon-based resources from waste is a critical need for achieving carbon neutrality and reducing fossil carbon extraction. We demonstrate a new approach for extracting volatile fatty acids (VFAs) using a multifunctional direct heated and pH swing membrane contactor. The membrane is a multilayer laminate composed of a carbon fiber (CF) bound to a hydrophobic membrane and sealed with a layer of polydimethylsiloxane (PDMS); this CF is used as a resistive heater to provide a thermal driving force for PDMS that, while a highly hydrophobic material, is known for its ability to rapidly pass gases, including water vapor. The transport mechanism for gas transport involves the diffusion of molecules through the free volume of the polymer matrix. CF coated with polyaniline (PANI) is used as an anode to induce an acidic pH swing at the interface between the membrane and water, which can protonate the VFA molecule. The innovative multilayer membrane used in this study has successfully demonstrated a highly efficient recovery of VFAs by simultaneously combining pH swing and joule heating. This novel technique has revealed a new concept in the field of VFA recovery, offering promising prospects for further advancements in this area. The energy consumption was 3.37 kWh/kg for acetic acid (AA), and an excellent separation factor of AA/water of 51.55 ± 2.11 was obtained with high AA fluxes of 51.00 ± 0.82 g.m^-2hr^-1. The interfacial electrochemical reactions enable the extraction of VFAs without the need for bulk temperature and pH modification.

Multifunctional magnetic sponge with outstanding solar/electro-thermal performance for high-efficiency and all-day continuous cleanup of crude oil spills

The high-efficient, eco-friendly and low-energy cleanup of viscous crude oil spills is still a global challenge. Emerging absorbents with self-heating function are promising candidates due to that they can significantly decrease crude oil viscosity via in-situ heat transfer so as to accelerate remediation. Herein we developed a novel multifunctional magnetic sponge (P-MXene/Fe₃O₄@MS) with outstanding solar/electro-thermal performance by facilely coating Ti₃C₂T_X MXene, nano-Fe₃O₄ and polydimethylsiloxane onto melamine sponge for fast crude oil recovery. Superior hydrophobicity (water contact angle of 147°) and magnetic responsivity allowed P-MXene/Fe₃O₄@MS to be magnetically driven for oil/water separation and easy recycling. Owing to excellent full-solar-spectrum absorption (average absorptivity of 96.5 %), effective photothermal conversion and high conductivity (resistance of 300 Ω), P-MXene/Fe₃O₄@MS possessed remarkable solar/Joule heating capability. The maximum surface temperature of P-MXene/Fe₃O₄@MS could quickly reach 84 °C under a solar irradiation of 1.0 kW/m² and 100 °C after applying a voltage of 20 V. The generated heat induced a significant decrease of crude oil viscosity, enabling the composite sponge to absorb more than 27 times its weight of crude oil within 2 min (1.0 kW/m² irradiation). More importantly, by means of the synergistic effect of Joule heating and solar heating, a pump-assisted absorption device based on P-MXene/Fe₃O₄@MS was able to realize the high-efficiency and all-day continuous separation of high-viscosity oil on water surface (crude oil flux = 710 kg m^-2 h^-1). The new-typed multifunctional sponge provides a competitive approach for dealing with large-area crude oil pollution.

Mathematical analysis of mixed convective stagnation point flow over extendable porous riga plate with aggregation and joule heating effects

It is still not quite apparent how suspended nanoparticles improve heat transmission. Multiple investigations have demonstrated that the aggregation of nanoparticles is a critical step in improving the thermal conductivity of nanofluids. However, the thermal conductivity of the nanofluid would be greatly affected by the fractal dimension of the nanoparticle aggregation. The purpose of this research is to learn how nanoparticle aggregation, joule heating, and a heat source affect the behavior of an ethylene glycol-based nanofluid as it flows over a permeable, heated, stretched vertical Riga plate and through a porous medium. Numerical solutions to the present mathematical model were obtained using Mathematica's Runge-Kutta (RK-IV) with shooting technique. In the stagnation point flow next to a permeable, heated, extending Riga plate, heat transfer processes and interrupted flow phenomena are defined and illustrated by diagrams in the proposed mixed convection, joule heating, and suction variables along a boundary surface. Data visualizations showed how different variables affected temperature and velocity distributions, skin friction coefficient, and the local Nusselt number. The rates of heat transmission and skin friction increased when the values of the suction parameters were raised. The temperature profile and the Nusselt number both rose because of the heat source setting. The increase in skin friction caused by changing the nanoparticle volume fraction from φ=0.0 to φ=0.01 for the without aggregation model was about 7.2% for the case of opposing flow area (λ=-1.0) and 7.5% for the case of aiding flow region (λ=1.0). With the aggregation model, the heat transfer rate decreases by approximately 3.6% for cases with opposing flow regions (λ=-1.0) and 3.7% for cases with assisting flow regions (λ=1.0), depending on the nanoparticle volume fraction and ranging from φ=0.0 to φ=0.01, respectively. Recent findings were validated by comparing them to previously published findings for the same setting. There was substantial agreement between the two sets finding.

Ag Nanoparticle-Thiolated Chitosan Composite Coating Reinforced by Ag-S Covalent Bonds with Excellent Electromagnetic Interference Shielding and Joule Heating Performances

Conductive composite coatings are an important element in flexible electronics research and are widely used in energy transformation, artificial intelligence, and electronic skins. However, the comparatively low electrical conductivity limits their performance in many specific applications, such as electromagnetic interference (EMI) shielding and Joule heating devices. Therefore, the preparation of ultrahigh-electrical conductivity composite coatings with good flexibility and durability remains a great challenge. Herein, we fabricated multifunctional conductive composite coatings based on thiolated chitosan (TCS) and Ag nanoparticles (AgNPs) by an eco-friendly drop-coating method. The three-dimensional conductive network constructed by thermal sintering imparted the coating with an ultrahigh electrical conductivity of up to 67079.4 S/m. Moreover, the coating reinforced by Ag-S covalent bonding exhibits good stability, including heat resistance, chemical resistance, and mechanical stability. In addition, based on the ultrahigh electrical conductivity, the coating exhibits superior EMI shielding effectiveness and Joule heating capability. With 30 wt % of AgNPs in the coating, the EMI shielding effectiveness of the coating reaches 70.2 dB, far exceeding commercial standards. Additionally, the coating can quickly reach a saturation temperature (T_s) of 195.9 °C at a safe drive voltage of 3 V. These excellent performances demonstrate that the robust and flexible highly conductive composite coatings prepared by this method have attractive potential for EMI shielding and thermal management applications as well as in wearable electronics.

Stiffness Variable Polymer for Soft Actuators with Sharp Stiffness Switch and Fast Response

Stiffness variable polymers are an essential family of materials that have aroused considerable attention in soft actuators. Although lots of strategies have been proposed to achieve variable stiffness, it remains a formidable challenge to achieve a polymer with a wide stiffness range and fast stiffness change. Herein, a series of variable stiffness polymers with a fast stiffness change and wide stiffness range were successfully synthesized, and the formulas were optimized via Pearson correlation tests. The rigid/soft stiffness ratio of the designed polymer samples can reach up to 1376-folds. Impressively, owing to the phase-changing side chains, the narrow endothermic peak can be observed with full width at half-maximum within 5 °C. Moreover, the shape memory properties of the shape fixity (R_f) and shape recovery ratio (R_r) values of the shape memory properties could reach up to 99.3 and 99.2%, respectively. Then, the obtained polymer was introduced into a kind of designed 3D printing soft actuator. The soft actuator can achieve sharp heating-cooling cycle of 19 s under a 1.2 A current with 4 °C water as coolant and can lift a 200 g weight at the actuating state. Moreover, the stiffness of the soft actuator can reach up to 718 mN/mm. The soft actuator exhibits an outstanding actuate behavior and stiffness switchable capability. We expect our design strategy and obtained variable stiffness polymers to be potentially applied in soft actuators and other devices.

Facile fabrication of solar-heating and Joule-heating hyperelastic MXene-modified sponge for fast all-weather clean-up of viscous crude oil spill

Developing rational sorbent for viscous crude oil clean-up is still a daunting challenge, which requires rapid oil-uptake capability and scalable fabrication process. Herein, a heatable hydrophobic sponge sorbent (H-MXene/PVA/MS) with excellent light/Joule-heating performances was fabricated by a simple and feasible top-down approach. MXene nanosheets firmly coated on the substrate skeleton gave the sorbent outstanding ability to convert solar/electricity into heat rapidly due to the localized surface plasmon resonance (LSPR) effect and ultrahigh metallic conductivity. The surface temperature of H-MXene/PVA/MS could reach about 80 ℃ under 1.0 sun irradiation within 30 s and 125 ℃ under a low applying voltage of 6 V within 25 s. The rapid and sufficient heat generation on the sorbent would effectively warm the surrounding oil and accelerate its absorption. The oil absorption rate under 1.0 sun irradiation (1 kW/m²) improved about 41.5 times compared to the unheated sorbent. Moreover, the sorbent showed practical application potential in harsh environments due to its high coating firmness, durability, elasticity, and suitability for large-scale production and operations. Thus, the easily-prepared H-MXene/PVA/MS sorbent, which mainly focuses on solar-heating, supplemented by Joule-heating, provides an efficient and energy-efficient strategy for addressing large-scale viscous oil spill clean-up.

Versatile Electronic Textile Enabled by a Mixed-Dimensional Assembly Strategy

Electronic textiles (e-textiles) hold great promise for serving as next-generation wearable electronics owing to their inherent flexible, air-permeable, and lightweight characteristics. However, these e-textiles are of limited performance mainly because of lacking powerful materials combination. Herein, a versatile e-textile through a simple, high-efficiency mixed-dimensional assembly of 2D MXene nanosheets and 1D silver nanowires (AgNWs) are presented. The effective complementary actions of MXene and AgNWs endow the e-textiles with superior integrated performances including self-powered pressure sensing, ultrafast joule heating, and highly efficient electromagnetic interference (EMI) shielding. The textile-based self-powered smart sensor systems obtained through the screen-printed assembly of MXene-based supercapacitor and pressure sensor are flexible and lightweight, showing ultrahigh specific capacitance (2390 mF cm^-2 ), robust areal energy density (119.5 µWh cm^-2 ), excellent sensitivity (474.8 kPa^-1 ), and low detection limit (1 Pa). Furthermore, the interconnected conductive MXene/AgNWs network enables the e-textile with ultrafast temperature response (10.4 °C s^-1 ) and outstanding EMI shielding effectiveness of ≈66.4 dB. Therefore, the proposed mixed-dimensional assembly design creates a multifunctional e-textile that offers a practical paradigm for next-generation smart flexible electronics.

Electrical Heaters for Anti/De-Icing of Polymer Structures

The problem of icing for surfaces of engineering structures requires attention more and more every year. Active industrialization in permafrost zones is currently underway; marine transport in Arctic areas targets new goals; the requirements for aerodynamically critical surfaces of wind generators and aerospace products, serving at low temperatures, are increasing; and fiber-reinforced polymer composites find wide applicability in these structural applications demanding the problem of anti/de-icing to be addressed. The traditional manufacturing approaches are superimposed with the new technologies, such as 3D printers and robotics for laying heat wires or cheap and high-performance Thermal Sprayed methods for metallic cover manufacturing. Another next step in developing heaters for polymer structures is nano and micro additives to create electrically conductive heating networks within. In our study, we review and comparatively analyze the modern technologies of structure heating, based on resistive heating composites.

Multifunctional MoSe2 @MXene Heterostructure-Decorated Cellulose Fabric for Wearable Thermal Therapy

A booming demand for wearable electronic devices urges the development of multifunctional smart fabrics. However, it is still facing a challenge to fabricate multifunctional smart fabrics with satisfactory mechanical property, excellent Joule heating performance, highly efficient photothermal conversion, outstanding electromagnetic shielding effectiveness, and superior anti-bacterial capability. Here, a MoSe₂ @MXene heterostructure-based multifunctional cellulose fabric is fabricated by depositing MXene nanosheets onto cellulose fabric followed by a facile hydrothermal method to grow MoSe₂ nanoflakes on MXene layers. A low-voltage Joule heating therapy platform with rapid Joule heating response (up to 230 °C in 25 s at a supplied voltage of 4 V) and stable performance under repeated bending cycles (up to 1000 cycles) is realized. Besides, the multifunctional fabric also exhibits excellent photothermal performance (up to 130 °C upon irradiation for 25 s with a light intensity of 400 mW cm^-2 ), outstanding electromagnetic interference shielding effectiveness (37 dB), and excellent antibacterial performances (>90% anti-bacterial rate toward Escherichia coli, Bacillus subtilis, and Staphylococcus aureus). This work offers an efficient avenue to fabricate multifunctional wearable thermal therapy devices for mobile healthcare and personal thermal management.

Room Temperature Polymorphism in WO3 Produced by Resistive Heating of W Wires

Polymorphous WO₃ micro- and nanostructures have been synthesized by the controlled Joule heating of tungsten wires under ambient conditions in a few seconds. The growth on the wire surface is assisted by the electromigration process and it is further enhanced by the application of an external electric field through a pair of biased parallel copper plates. In this case, a high amount of WO₃ material is also deposited on the copper electrodes, consisting of a few cm2 area. The temperature measurements of the W wire agrees with the values calculated by a finite element model, which has allowed us to establish the threshold density current to trigger the WO₃ growth. The structural characterization of the produced microstructures accounts for the γ-WO₃ (monoclinic I), which is the common stable phase at room temperature, along with low temperature phases, known as δ-WO₃ (triclinic) on structures formed on the wire surface and ϵ-WO₃ (monoclinic II) on material deposited on external electrodes. These phases allow for a high oxygen vacancies concentration, which is interesting in photocatalysis and sensing applications. The results could help to design experiments to produce oxide nanomaterials from other metal wires by this resistive heating method with scaling-up potential.

Effect of Pulsed Current-Assisted Tension on the Mechanical Behavior and Local Strain of Nickel-Based Superalloy Sheet

Electrically assisted (EA) forming is a plastic forming technique under the coupling action of multiple energy fields, such as force field, temperature field, and electric field. It is suitable for the forming of difficult-to-deform materials such as nickel-based superalloys. In this paper, uniaxial tensile tests on nickel-based superalloy sheets were carried out using the pulsed current assisted with different parameters. The experimental results show that the flow stress of the material decreased with the increase in the current density under a high-frequency pulsed current, and the Joule heating effect explains the flow stress drop. In the pulsed current application process, the different types of Portevin-Le Chatelier phenomena appeared with the increase in the current density. The decrease in elongation assisted by the pulsed current was explained by analyzing the inhomogeneity of the maximum Joule heating temperature distribution. In addition, the digital image correlation (DIC) analysis was used to analyze the local strain behavior of the pulsed current-assisted tensile process. Under the application of a high-frequency pulse current, the specimen exerted an inhomogeneous temperature increase and local hot pressing stress, which resulted in the inhomogeneous distribution of the local strain.