High Joule Heating Research Articles

High Joule heat as a risk factor for post-endoscopic submucosal dissection electrocoagulation syndrome: A multicenter prospective study.

Thermal damage may lead to inflammation of the peeled mucosal surface during endoscopic submucosal dissection (ESD). To determine the effect of Joule heat on the onset of post-ESD electrocoagulation syndrome (PECS). In this prospective study, PECS was characterized by in-hospital fever (white blood cell count: ≥ 10000 μ/L or body temperature ≥ 37.5 °C) and abdominal pain (visual analog scale score ≥ 30 mm during hospitalization or increased by ≥ 20 mm from baseline at admission). High Joule heat was defined as 15390 J. Between April 2020 and April 2024, 209 patients underwent colorectal ESD; those with intraoperative perforation or penetration were excluded. The remaining 202 patients were divided into the PECS and non-PECS groups. PECS occurred in 30 (14.9%) patients. Multivariate analysis revealed high Joule heat as an independent factor associated with PECS (odds ratio = 7.96; 95% confidence interval: 2.91-21.8, P < 0.01). The procedure time and presence of lesions in the right colon were not associated with PECS. Accumulated thermal damage on the peeled mucosal surface should be considered during PECS onset. This thermal damage is likely a major component of the mechanism underlying PECS.

Upcycling of waste diamond wire sawing silicon powders to prepare Al-50Si composite by hot-pressing sintering

The disposal of waste diamond wire sawing silicon powders (DWSSP) generated during solar-grade silicon wafer production is crucial for the sustainable development of the photovoltaic industry. To achieve the resourceful utilization of DWSSP, a method to prepare Al-50Si composite by upcycling DWSSP through hot-pressing sintering (HPS) was proposed. The effects of hot-pressing sintering temperature, pressure, and current on the densification of DWSSP and Al powders were investigated by finite element modeling analyses and experiments validation. The numerical simulation results showed that pressure-assisted sintering triggered the percolation effect of interparticle currents coupled with localized high Joule heat, accelerating the interfacial reaction between DWSSP and Al powders. It was found that the Vickers hardness and density of the prepared Al-50Si composite increased and then decreased at sintering temperatures of 450 to 500°C and showed a positive correlation at pressures of 50 to 200MPa. Optimal conditions of 475 °C sintering temperature, 150MPa sintering pressure, and 5min holding time yielded Al-50Si composite with a density of 2.36g/cm3 and a Vickers hardness of 201 HV0.1. The findings demonstrate the application of HPS method allows for the grave-to-cradle waste management of DWSSP and the preparation of recycled Al-50Si composite for its high value-added utilization.

Multifunctional green synthesized silver nanoparticle and polypyrrole-based e-textile for wearable thermoregulation applications

Electronic textiles (e-textiles) build upon existing technologies to develop truly smart textiles: garments that sense, react, and adapt. Thermoregulatory e-textiles are an area of significant interest across the field. Designing e-textiles that satisfy electrical performance and simple construction is a significant challenge. To address these issues, a simple dip-coating and in-situ polymerization method was used to develop the first example of a thermoregulatory e-textile using green synthesized silver nanoparticles (AgNP) and polypyrrole (Ppy), based on the method previously reported (Naysmith, A.; Mian, N.S.; Rana, S. Development of conductive textile fabric using Plackett–Burman optimized green synthesized silver nanoparticles and in situ polymerized polypyrrole. Green Chemistry Letters and Reviews 2023, 16 (1)). This methodology was optimized using a Taguchi statistical design determining the optimal AgNP-Ppy synthesis method to obtain high performance Joule heating e-textiles, novel within the field of e-textiles. Reactant concentration and reaction time had the largest effects on the electrical resistance of subsequent e-textiles. The result is the first example of an e-textile heater based on green synthesized AgNPs. The e-textile demonstrated exceptional Joule heating (120°C), low electrical resistance (37 Ω), resistive temperature sensing behavior (negative TCR = −0.0046), and increased thermal conductivity (19.55 l (Wm−1 K−1)); the strain sensing behavior (gauge factor = −0.07). This work extends knowledge of the development and challenges within e-textile technologies as the field creates the next generation of textiles.

Research Overview on the Electromigration Reliability of SnBi Solder Alloy.

Due to the continuous miniaturization and high current-carrying demands in the field of integrated circuits, as well as the desire to save space and improve computational capabilities, there is a constant drive to reduce the size of integrated circuits. However, highly integrated circuits also bring about challenges such as high current density and excessive Joule heating, leading to a series of reliability issues caused by electromigration. Therefore, the service reliability of integrated circuits has always been a concern. Sn-based solders are widely recognized in the industry due to their availability, minimal technical issues during operation, and good compatibility with traditional solders. However, solders that are mostly Sn-based, such as SAC305 and SnZn, have a high melting point for sophisticated electronic circuits. When Bi is added, the melting point of the solder decreases but may also lead to problems related to electromigration reliability. This article reviews the general principles of electromigration in SnBi solder joints on Cu substrates with current flow, as well as the phenomena of whisker formation, voids/cracks, phase separation, and resistance increase caused by atomic migration due to electromigration. Furthermore, it explores methods to enhance the reliability of solder joint by additives including Fe, Ni, Ag, Zn, Co, RA (rare earth element), GNSs (graphene nanosheets), FNS (Fullerene) and Al2O3. Additionally, modifying the crystal orientation within the solder joint or introducing stress to the joint can also improve its reliability to some extent without changing the composition conditions. The corresponding mechanisms of reliability enhancement are also compared and discussed among the literature.

Uniform and welded networks of silver nanowires surface-embedded on cellulose yarns with PEDOT:PSS passivation for sustainable E-textiles

Electronic textiles are critical for wearable electronics and real-time health care monitoring. The use of cellulose fibers with conductive components to construct optimized materials for enhanced performance remains an ongoing mission. We report the use of continuous dip-coating of hydrogel fibers to fabricate conductive cellulose yarns (CCYs). Uniform, interwelded and compact silver nanowire (AgNW) networks are embedded on the surfaces of the cellulose yarns, after which a PEDOT:PSS passivation layer is applied to ensure the reliability and practicality of the CCYs. This unique AgNW network provids high electrical conductivity of the CCYs, high strain sensitivities and good Joule heating. Wearable fabric devices embroidered with CCYs exhibit superior performance in strain sensing and electrothermal insulation. This CCY realizes the organic combination of manufacturing, practicability and functionality in sustainable E-textiles. The CCY has the potential to enable scalable manufacturing of low-cost wearable sensors integrated into everyday clothes.

Spectroradiometry with sub-microsecond time resolution using multianode photomultiplier tube assemblies.

Accurate and precise measurements of spectroradiometric temperature are crucial for many high pressure experiments that use diamond anvil cells or shock waves. In experiments with sub-millisecond timescales, specialized detectors such as streak cameras or photomultiplier tubes are required to measure temperature. High accuracy and precision are difficult to attain, especially at temperatures below 3000K. Here, we present a new spectroradiometry system based on multianode photomultiplier tube technology and passive readout circuitry that yields a 0.24 µs rise-time for each channel. Temperature is measured using five color spectroradiometry. During high pressure pulsed Joule heating experiments in a diamond anvil cell, we document measurement precision to be ±30 K at temperatures as low as 2000K during single-shot heating experiments with 0.6 µs time-resolution. Ambient pressure melting tests using pulsed Joule heating indicate that the accuracy is ±80 K in the temperature range 1800-2700K.

Solar-Powered Switch of Antiferromagnetism/Ferromagnetism in Flexible Spintronics.

The flexible electronics have application prospects in many fields, including as wearable devices and in structural detection. Spintronics possess the merits of a fast response and high integration density, opening up possibilities for various applications. However, the integration of miniaturization on flexible substrates is impeded inevitably due to the high Joule heat from high current density (1012 A/m2). In this study, a prototype flexible spintronic with device antiferromagnetic/ferromagnetic heterojunctions is proposed. The interlayer coupling strength can be obviously altered by sunlight soaking via direct photo-induced electron doping. With the assistance of a small magnetic field (±125 Oe), the almost 180° flip of magnetization is realized. Furthermore, the magnetoresistance changes (15~29%) of flexible spintronics on fingers receiving light illumination are achieved successfully, exhibiting the wearable application potential. Our findings develop flexible spintronic sensors, expanding the vision for the novel generation of photovoltaic/spintronic devices.

Programming Anisotropic Functionality of 3D Microdenticles by Staggered-Overlapped and Multilayered Microarchitectures.

Natural sharkskin features staggered-overlapped and multilayered architectures of riblet-textured anisotropic microdenticles, exhibiting drag reduction and providing a flexible yet strong armor. However, the artificial fabrication of three-dimensional (3D) sharkskin with these unique functionalities and mechanical integrity is a challenge using conventional techniques. In this study, it is reported on the facile microfabrication of multilayered 3D sharkskin through the magnetic actuation of polymeric composites and subsequent chemical shape fixation by casting thin polymeric films. The fabricated hydrophobic sharkskin, with geometric symmetry breaking, achieves anisotropic drag reduction in frontal and backward flow directions against the riblet-textured microdenticles. For mechanical integrity, hard-on-soft multilayered mechanical properties are realized by coating the polymeric sharkskin with thin layers of zinc oxide and platinum, which have higher hardness and recovery behaviors than the polymer. This multilayered hard-on-soft sharkskin exhibits friction anisotropy, mechanical robustness, and structural recovery. Furthermore, coating the MXene nanosheets provides the fabricated sharkskin with a low electrical resistance of ≈5.3 Ω, which leads to high Joule heating (≈229.9°C at 2.75V). The proposed magnetomechanical actuation-assisted microfabrication strategy is expected to facilitate the development of devices requiring multifunctional microtextures.

Super-flexible and highly conductive H-Ti3C2Tx MXene composite films with 3D macro-assemblies for electromagnetic interference shielding

2D MXene are showing great prospects for EMI shielding by virtue of abundant surface functional groups and outstanding metallic electrical conductivity. However, it remains a great challenge to simultaneously achieve flexible, lightweight and high stability in MXene shielding materials due to inferior mechanical strength and poor oxidation stability. Gelation paves up an effective and facile strategy to develop highly stable and conductive 3D porous Ti3C2Tx architectures. Herein, super-flexible and highly conductive H-Ti3C2Tx MXene composite films with 3D macro-assemblies for EMI shielding were fabricated through a gelation-densification process initiated by hydrochloric acids, and two-step vacuum-assisted filtration followed by freeze-casting approach. The obtained nanocomposite films manifest satisfactory mechanical properties with a tensile strength of 116.51 MPa, excellent EMI SE of 55.14 dB, superior SSE/t and high EMI SE retention after 5000 cycles of bending deformation. In addition, the as-prepared nanocomposite papers demonstrate outstanding thermal management performances such as rapid response time, high Joule heating temperature (118 °C) at low applied voltage (2.5 V) and eminent working stability (4000 s).

Rapid Fabrication of Flexible Cu@Ag Flake/SAE Composites with Exceptional EMIS and Joule Heating Performance.

High electromagnetic interference shielding (EMIS) effectiveness and good thermal management properties are both required to meet the rapid development of integrated electronic components. However, it remains challenging to obtain environmentally friendly and flexible films with high EMIS and thermal management performance in an efficient and scalable way. In this paper, an environmentally friendly strategy is proposed to synthesize multifunctional waterborne Cu@Ag flake conductive films using water as the solvent and silicone-acrylic emulsion (SAE) as a matrix. The obtained films show high electrical conductivity and exceptional EMI SE and electrothermal conversion properties. The EMI SE in the X-band is higher than 76.31 dB at a thickness of 60 μm owing to the ultrahigh electrical conductivity of 1073.61 S cm-1. The film warms up quickly to 102.1 °C within 10 s under a low voltage of 2.0 V. In addition, the shielding coating is sufficiently flexible to retain a conductivity of 93.4% after 2000 bending-release cycles with a bending radius of 3 mm. This work presents an alternative strategy to produce high EMIS effectiveness and Joule heating films for highly integrated and flexible electronic components in a green, scalable, and highly efficient way.

Electrical Activity and Extremes of Individual Suspended ZnO Nanowires for 3D Nanoelectronic Applications.

We explored the electrical activity and extremes inside individual suspended zinc oxide (ZnO) nanowires (NWs) (diameter: 50-550 nm, length: 5-50 μm) subjected to high forward bias-induced Joule heating using two-terminal current-voltage measurements. NWs were isolated using a reproducible nanometrology technique, employing a nanomanipulator inside a scanning electron microscope. Schottky behavior is observed between installed tips and ZnO NW. The suspended ZnO NWs exhibited an average electrical resistivity ρ (approximately 2.3 × 10-2 Ω cm) and a high electron density n (exceeding 1.89 × 1018 cm-3), comparable to that of InP NWs, GaN NWs, and InAs NWs (1018∼1019 cm-3), suggesting the potential to drive advancements in high-performance NW devices. A maximum breakdown current density (JBD) of ∼0.14 MA/cm2 and a maximum breakdown power density (PBD) of 6.93 mW/μm3 were obtained, both of which are higher than substrate-bound ZnO NWs and consistent with previously reported results obtained from probed ZnO NWs grown vertically on the substrate. Moreover, we discovered that NWs experienced thermal breakdown due to Joule heating and exploited this breakdown mechanism to further investigate the temperature distribution along the ZnO NWs, as well as its dependence on the electrical properties and thermal conductance of contact electrodes. Thermal conductance was determined to be ∼0.4 nW K-1 and ∼1.66 pW K-1 at the tungsten(W)-ZnO NW and platinum(Pt)-ZnO NW contacts, respectively. In addition, we measured the elastic modulus (130-171 GPa), which closely approximated bulk values. We also estimated the nanoindentation hardness to be between 5 and 10 GPa. This work provides valuable insights into the electrical activity and extreme mechanisms, thus providing a better understanding of the potentials and limitations associated with utilizing suspended NWs in 3D nanodevices.

Impermeable Graphene Skin Increases the Heating Efficiency and Stability of an MXene Heating Element.

A Joule heater made of emerging 2D nanosheets, i.e., MXene, has the advantage of low-voltage operation with stable heat generation owing to its highly conductive and uniformly layered structure. However, the self-heated MXene sheets easily get oxidized in warm and moist environments, which limits their intrinsic heating efficiencies. Herein, an ultrathin graphene skin is introduced as a surface-regulative coating on MXene to enhance its oxidative stability and Joule heating efficiency. The skin layer is deposited on MXene using a scalable solution-phased layer-by-layer assembly process without deteriorating the excellent electrical conductivity of the MXene. The graphene skin comprises narrow and hydrophobic channels, which results in ≈70 times higher water impermeability of the hybrid film of graphene and MXene (GMX) than that of the pristine MXene. A complementary electrochemical analysis confirms that the graphene skin facilitates longer-lasting protection than conventional polymer coatings owing to its tortuous pathways. In addition, the sp2 planar carbon surface with a low heat loss coefficient improves the heating efficiency of the GMX, indicating that this strategy is promising for developing adaptive heating materials with a tractable voltage range and high Joule heating efficiency.

Multifunctional phase change textiles with electromagnetic interference shielding and multiple thermal response characteristics

Electromagnetic interference (EMI) shielding textiles with flexible thermal response are ideal candidates for applications in electromagnetic radiation protection, flexible electronic and information security. In general, silicone resins used to encapsulate textiles can delay the thermal response, which seriously limits the application of textiles in multiple scenarios. Herein, we have developed a flexible solid–solid phase change material (PCM) coating which is achieved by self-crosslinking polyethylene glycol (PEG) with highly reactive silanol group obtained by reaction with 3-isocyanatopropyltriethoxysilane (IPTS). The solid–solid PCM coating retains the phase change behavior of original PEG while providing excellent shape stabilization. Subsequently, the solid–solid PCM coating is used to encapsulate polymer textiles decorated with silver nanowires (AgNWs) based on a scalable dip coating strategy. Notably, the phase change textiles have an EMI shielding effectiveness of approximately 72 dB at the thickness of 0.26 mm and exhibit an energy storage density of 86.6 J g−1. Meanwhile, the textiles exhibit flexible thermal response such as high joule heating efficiency, excellent heat storage and release, good heat dissipation, and infrared anti-counterfeiting behavior. Thus, multifunctional textiles decorated with AgNWs and subsequently encapsulated with solid–solid PCM coatings have great promise for wearable clothing, electromagnetic radiation protection and personal thermal management.

The particularly clean response of the Indian sector to a strong but short lived geomagnetic storm

Using data from multiple sources/techniques, we have studied the low latitude ionospheric response to an intense geomagnetic storm (Dst ∼ −132 nT) in the Indian sector. The storm, which occurred on 30–31 May 2005, had the onset near noon in the Indian sector. It led to strong and sustained activity at high latitudes for twelve hours. Magnetometer data located near the magnetic equator produced clear evidence for a strong Prompt Penetration Electric Field (PPEF). Based on the TEC data going as far north as Delhi, there were clear indications that the PPEF was followed by a Storm Enhanced Density (SED) event. On the next day, i.e., 31 May, there was a strong counter-electrojet in the morning, accompanied by a factor 3 reduction in the plasma density in the Equatorial Ionization Anomaly (EIA) region and beyond. This was consistent with the notion of a vanishing eastward electric field at the equator and the direct impact of an upper thermospheric equatorward wind associated with high latitude Joule heating from the auroral regions. One unexpected feature from the afternoon of 31 May was an undulation in the height of the peak F-region density at the magnetic equator in Trivandrum. A closer look at the ionosonde data revealed an F3 layer until mid-afternoon, strongly indicative of equatorward winds in the upper thermosphere. However, by 16:00 IST, the F3 layer quickly vanished; and with this, the height of the peak-F region density fell by 200 km in two hours. The only plausible explanation was that the winds must have stopped blowing toward the equator by 16:00 IST.

Key Parameters and Optimal Design of a Split Induction Coil for T-Shaped Pipe Brazing

The heat exchanger made up of several T-shaped joints is a critical component in energy equipment. A split induction coil was designed for T-shaped aluminum pipe brazing, and the Taguchi method was combined with multi-physical simulation to solve the multi-factor optimization of the split coil. The results showed that the multi-physical simulation model had high precision. The melting of filler metal was almost consistent with the spatial distribution of the temperature field, and the average simulation error was approximately 5.753 °C. The optimal coil parameters were obtained with a turn number of 3.5, a turn space of 7 mm, a heating distance of 15.6 mm, a coil diameter of 8 mm, and a coil length of 9 mm. Three well-formed T-shaped joints could be obtained at one time via the optimal split coil. During the induction brazing, the skin effects and the proximity effects induced a high magnetic field intensity around the joint, which had a significant relationship with the coil length and coil diameter. The high magnetic field intensity promoted a high eddy current density in this place, and as a result, the high Joule heat could be generated around the joint. In addition, the significant decrease in the heating rate at high temperatures promoted the homogenization of the temperature and the melting and filling of the filler metal as well as avoided local overheating.

Achieving high joule heating and self-cleaning performance in copper-coated fabrics with excellent microwave shielding

Achieving high joule heating and self-cleaning performance in copper-coated fabrics with excellent microwave shielding

Bioinspired bistable dielectric elastomer actuator based on low-melting-point alloy phase change regulation

Soft bistable actuators that exhibit flexibility, fast response, and low energy consumption are key components for applications such as fast grippers, shape reconfiguration actuators, and deployable soft robots. Inspired by the structure of rhododendron leaves, we designed a bistable dielectric elastomer actuator (BDEA) by integrating a dielectric elastomer with a low-melting-point alloy. The developed BDEA can operate reversibly between two stable states through the synergistic application and control of high voltage and Joule heating. The transition process between the two stable states of the actuator was elucidated using finite element analysis. The bending angles of the actuator in the two deformation directions were measured, and grasping experiments were performed. The experimental results show that the direction and magnitude of deformation of the bistable actuator can be tuned to conform to the shape of the target object. The developed BDEA has enhanced shape adaptability and higher bearing capacity compared to conventional soft actuators.

A Flexible Strain Sensor with High Electrical Conductivity, Rapid Electrothermal Response, and High Strain Sensitivity for Real‐Time Monitoring of Human Joint Movement

AbstractHerein, a flexible film, called PPA film, is designed as a multifunctional sensor with high electrical conductivity, rapid electrothermal response, and high strain sensitivity. The film contains polyvinyl alcohol (PVA), graphene nanosheets (GNs), nanocellulose crystals (CNCs), polydopamine (PDA), and silver nanoparticles (Ag NPs), symbolized as PPA film. The CNCs enhance the dispersion of the GNs during film formation; the stacked GNs change heat conduction and resistance during film bending; PDA serves as a linking agent; Ag NPs improve the conductivity (i.e., 2.65 × 103 S/m) of the film during electrothermal response measurement. A flexible strain sensor designed from PPA films is mounted on the skin surface of human joints to monitor human movement in real time. The sensor exhibited good stability and cycling durability, i.e., the resistance variation remained stable during the bend‐release repetitions for 600 cycles at 1.2 % strain. The flexible sensors exhibited highly sensitive to bending strain, i.e., 30.5 of the gauge factor (GF), and can be applied to monitor bending motions of human joints, such as finger, wrist, elbow, and knee joints.In addition, the PPA films exhibit very high joule heat generation ability and demonstrate its applicability as a joint or stomach warmer and sensor. The as‐designed flexible sensor is a promising candidate for application in environmentally friendly and multifunctional wearable devices.

Biomimetic, fire-resistant, ultralight and porous carbon fiber sponges enabling safe and efficient remediation of crude oil spills in harsh environments

Advanced absorbents must meet the requirements of superior hydrophobic/oleophilic behavior, favorable adsorption efficiency, and high photothermal and Joule heating performance to handle frequent crude oil spills. However, current carbon-based absorbents suffer from poor fire resistance, thus severely limiting their application in harsh environments. Herein, inspired by a bird's nest, a polymer “welding” strategy is proposed to design a versatile absorbent in which the polymer serves as a “binder” to interconnect discontinuous fibers together to form a 3D welded structure. The continuous conductive networks endow the absorbent with high photothermal and Joule heating effect, thus achieving all-weather adsorption, and improving the adsorption efficiency of crude oil via the self-heating function. Compared with other absorbents, the absorbent prepared via polymer welding technology exhibited preferable comprehensive performance, such as superhydrophobicity, high fire resistance, and high absorption efficiency. Specially, the noninflammable absorbent can restrain the combustion of crude oil, thereby reducing its combustion in case of fire. The versatile absorbent is expected to provide a promising solution for the safe and efficient cleanup of crude oil spills in harsh environments. Overall, the unique polymer welding strategy can be developed into a universal strategy for other material systems to expand their applications.

Preparation and properties of multifunctional polyurethane synthetic leather nanocomposites

Although leather can be functionally modified well, its origin will cause concern about the destruction of the ecological environment. Here, a novel multifunctional synthetic leather (denoted as FRTL) that integrates high tensile strength, flame retardancy, Joule heating, electromagnetic shielding, and strain sensing is reported. Benefiting from the excellent mechanical properties of the PU film, the leather exhibits a high tensile strength of 100.8 MPa. Based on the high conductivity of MXene, the leather possesses an electromagnetic shielding efficiency of 30.1 dB. FRTL also exhibits excellent flame retardancy, confirmed by the reduction of more than 32% in peak heat release rate. In addition, the controlled Joule heating properties enable the leather to cope with extreme cold weather. The obtained fabric can also detect various human movements. This work provides a facile method to fabricate the next-generation multifunctional protective leather, showing promising application in the field of smart firefighting.