Joule Effect Research Articles

Smart design for CBRN protection by coupling adsorption and photocatalysis: Regeneration adsorbent efficiency – CWAs’ continuous purification

This investigation and optimization of the adsorption and photocatalysis coupling process for treating chemical warfare agents (CWAs) were performed with a compact cartridge based on activated carbon felt (AF) and TiO2 photocatalyst deposited on luminous textiles. The target pollutants were simulants of the chemical warfare agent (yperite), methyl salicylate, diethyl sulfur (a simulant of sulfur mustard gas), and cyclohexane, which is the benchmark for type A gas filtration tests. To take better advantage of this new configuration, an optimization of the photocatalytic process was highlighted with an improvement of the regeneration process by implementing the integrated compactness of desorption by the Joule effect (in situ). In the case of methyl salicylate treatment, the recovery of the adsorption capacity of the AF were about 95% and a working time of 85% compared to initial adsorbent performance. For the second cycle regeneration, the recovered adsorption capacity was about 88% compared to initial capacity. We note also that the working time decrease by 15% for each regeneration step. The evaluation of the new coupling configuration aimed at highlighting the influence of a sulfur compound was encouraging, with a regeneration rate of the adsorbent of about 80%. Compared to MS, the regeneration seems to be more difficult. This is due to by-products (SO2, MSH) formation which is highlighted by the degradation pathway proposed. The removal efficiency of the coupling system (UV-LED/AF) under continuous process, was equal to 36%. This leads an increase in filter working time of 50 min over that of a conventional adsorption process. Special attention was paid to validating the coupling system performance in real conditions. The system was placed on a humanlike seated thermal manikin used to simulate an occupant of a chamber of 30 m3 with the realistic condition of applying chemical, biological, radiological, and nuclear (CBRN) agent protection. The time protection was 60 and 30 min for respective concentrations of about 150 and 300 mg.m−3.This global investigation addressed how to overcome the scientific barriers to designing a compact, self-contained filtration cartridge for personal protection in CBRN emergency response and management in accordance with the United Nations Sustainable Development Goals (SDGs).

Thermal characterization of Ge-rich GST/TiN thin multilayers for phase change memories

In the domain of phase change memories (PCMs), intensive research is conducted to reduce the programming cycle cost. The RESET operation is done by melting the PCM and then quenching the liquid phase to put it back to the amorphous state. In most of the devices, the heating is realized by the Joule effect with a titanium nitride (TiN) component put in contact with the PCM itself. One of the crucial points to improve the efficiency of this technology is to characterize the thermal contact between TiN and PCM. Having a low thermal resistance between the heater and the PCM ensures the heat transfer between the two is as efficient as possible. In this work, the interfacial thermal resistance between Ge-doped G2Sb2Te5 (GeGST)/TiN in multilayer systems has been characterized, and the influence of the compressive stress exerted by the TiN layers on the GeGST crystallization has been highlighted.

Characterization of the thermal conductivity and diffusivity of graphene nanoplatelets strips: a low-cost technique

This paper proposes a new technique to characterize the thermal conductivity and diffusivity of thin strips made by graphene nanoplatelets (GNP). The evaluation of these parameters is essential for a reliable design of thermal and electrothermal applications of graphene and is usually performed by means of assessed but expensive techniques such as those based on Raman effects and laser flash. The technique proposed here is simpler and less demanding in terms of equipment, and combines the results of an experimental characterization of the strip heated by the Joule effect obtained with infrared camera, with those provided by an electro-thermal model. Specifically, the evaluation of the thermal conductivity and diffusivity is the result of the analysis of the transient behavior of the measured and simulated solutions. The methodology is here successfully validated by applying it to commercial graphene strips and benchmarking against the thermal parameters provided by the manufacturers. Then, a complete characterization is provided for commercial strips based on different formulations of GNP and binders such as polyurethane, epoxy resin, and boron nitride. For these materials, the values of thermal conductivity and diffusivity are found in the ranges (50–450) W m−1 K−1 and (0.5–3.5) × 10−4 m2 s−1, respectively.

Onsager coefficients in a coupled-transport model displaying a condensation transition

We study nonequilibrium steady states of a one-dimensional stochastic model, originally introduced as an approximation of the discrete nonlinear Schrödinger equation. This model is characterized by two conserved quantities, namely mass and energy; it displays a ‘normal’, homogeneous phase, separated by a condensed (negative-temperature) phase, where a macroscopic fraction of energy is localized on a single lattice site. When steadily maintained out of equilibrium by external reservoirs, the system exhibits coupled transport herein studied within the framework of linear response theory. We find that the Onsager coefficients satisfy an exact scaling relationship, which allows reducing their dependence on the thermodynamic variables to that on the energy density for unitary mass density. We also determine the structure of the nonequilibrium steady states in proximity of the critical line, proving the existence of paths which partially enter the condensed region. This phenomenon is a consequence of the Joule effect: the temperature increase induced by the mass current is so strong as to drive the system to negative temperatures. Finally, since the model attains a diverging temperature at finite energy, in such a limit the energy–mass conversion efficiency reaches the ideal Carnot value.

Development of steel for hot stamping of 22mnb5 steel by joule effect heating

With the increase in demand and development of the automobile sector, where it becomes important to improve the efficiency of energy consumption of vehicles, one can observe the need for materials that are both light and have high mechanical strengths. The Ultra High Strength Steel (UHSS), which include TWIP (Twinning-Induced-Plasticity) and Hot Stamping are characterized by unique microstructures and metallurgical properties that allow car manufacturers to meet the diverse functional requirements of vehicles. Boron steel is suitable for mechanical hot forming. In the last few years, hot stamped parts have occupied a prominent place in the bodies of bodies due to being in line with the demands mentioned above. There is a lot of research under development for this technology, be it in materials, means of production, coatings and applications. Currently, there is a patent that generates a technological restriction for the processing of hot stamping; in which it is to use boron steel with Al-Si metallic coating and heating the blank to be hot stamped through a radiation furnace. The objective of this work is to use a new processing alternative through another metallic diffusion coating of Fe-Zn and heating of the blank to be hot stamped by Joule effect; generating an industrial experiment and prototyping for characterization. The results showed the feasibility of using boron steel with Fe-Zn diffusion coating in hot forming applications by heating by Joule effect, with good surface quality, meets the mechanical properties and microstructure, without cracks in the steel, excellent adhesion of the paint layer and good resistance to corrosion.

Mixed convection flow in a channel with a dimpled section and adiabatic cylindrical obstacle under the influence of magnetic and Joule effects

This study investigates the mixed convection flow in a channel with a dimpled section and an adiabatic cylindrical obstacle under the influence of a magnetic field. The channel has a heated dimpled portion, while the flat horizontal walls are adiabatic. The energy equation considers the Joule heating effect, and the resulting momentum and thermal transport equations are numerically solved using the Galerkin weighted residual finite element method. The study discusses the flow and heat transfer characteristics for different values of the Joule heating parameter, Reynolds, Hartman, and Rayleigh numbers. The results show that increasing Hartmann and Joule heating parameters reduce average heat transfer rates while increasing Prandtl, Reynolds, and Rayleigh numbers enhances it. This analysis's outcomes will help design Ohmic heating systems like magnetic fluid power actuators and thermal processing gadgets for particulate food products. The novel quantitative findings in this study include enhancement in heat transfer with increasing Prandtl, Reynolds, and Rayleigh numbers. Furthermore, the adiabatic cylindrical obstacle near the dimpled section significantly affects the heat transfer rates, resulting in complex flow patterns. The results of this study can be used in magnetic fluid power actuators, thermal processing gadgets for particulate food products, and heat exchangers.

Surface Acoustic Waves Equip Materials with Active De‐Icing Functionality: Unraveled Glaze Ice De‐Icing Mechanisms and Application to Centimeter‐Scale Transparent Surfaces

Enabling active de‐icing functionality on low heat conductive and transparent materials is a requirement for several seminal industries in critical economic sectors. However, developing efficient and environmentally friendly de‐icing methods still fails because of compatibility problems with large‐scale devices and real‐world conditions. In this paper, de‐icing several square centimeters covered with thick layers of glaze ice is approached through nanoscale activation by surface acoustic waves (SAWs). De‐icing functionality is demonstrated with a self‐supported piezoelectric material (LiNbO3) and a piezoelectric film (ZnO) deposited on fused silica, the latter system proving the compatibility of the method with materials of practical relevance. Its applicability to large and transparent substrates is demonstrated by placing the interdigitated electrodes (IDTs) required for activation close to the substrate's edges, leaving most of the surface unaltered. The de‐icing mechanism of glaze ice by SAW activation is revealed by simulating the SAW propagation on ice‐covered surfaces and by experimental analysis of the ice melting process. This involves a combination of ice mechanical stress activation and heating through the initially formed water/ice front. Possible Joule effects due to ohmic losses in the IDTs have been discarded, monitoring local temperature variations during SAW activation at and out of resonance conditions.

Development and implementation of direct electric cure of plain weave CFRP composites for aerospace

Curing aerospace composites is time-consuming with high energy requirements, particularly when using methods such as autoclaves, ovens and heated presses. This study investigates direct electric cure (DEC), which uses the Joule effect to directly heat carbon fibre composites to their cure temperature. Its benefits include a significant increase in energy efficiency, control over the cure temperature and low void content compared to oven curing. Samples were manufactured with vacuum-assisted resin transfer moulding (VARTM) and prepreg, as well as curing a two-meter-long leading-edge component, to demonstrate and evaluate the curing method at scale. The average void content for VARTM DEC samples was lower by 0.82 % compared to the oven-cured panel, however, the average degree of cure (DoC) decreased by 6.25 %. Normalised energy consumption for the cure was significantly reduced for all DEC cures, with VARTM cures using 99 % less energy than oven-cured components.

Analysis of the aging effects on the thermal runaway characteristics of Lithium-Ion cells through stepwise reactions

The current political vision to drastically reduce carbon emissions pushes the electrified powertrain into an increasingly important role in the transport sector. However, concerns related to the battery's effectiveness as an energy source need to be overcome to make this technology widespread. One such concern is safety, catching attention as development races towards greater battery energy density. In this way, cathodic chemistry is important since exothermic reactions are unleashed from the components that originally formed the active material. Furthermore, the aging process reduces the battery capacity, reducing the amount of active material and thickening the solid electrolyte interface, which increases the joule effect. For these reasons, thermal runaway under aging conditions must be investigated to assess potential safety issues. Using an accelerating rate colorimeter, the heat-induced thermal runaway tests were performed with two-cathode chemistry (NMC and LFP) under pristine and aged battery conditions. For aging the batteries, the ARC was coupled with a bidirectional source. Two ambient temperatures, 20 °C and 50 °C, were used for the aging tests, being the batteries cycled up to 250 cycles with a determined protocol for charge and discharge. A numerical model was fed with experimental tests, targeting optimizing the battery output parameters and obtaining geometric aspects that are difficult to measure. Unlike the single step model, a stepwise reactions model was created to assess the heat release from different battery components for pristine and aged conditions. The higher endothermic behavior from cathode decomposition and less oxygen released during this reaction make the LFP battery safer than the NMC. For aged batteries, the SEI growth consumes lithium and electrolyte, decreasing the quantity of both components in the anode. Thus, the anode and electrolyte reaction after SEI decomposition is lower, improving battery safety.

Penetration of waves in global stochastic conducting media.

The attenuation in the propagation of a plane wave in conducting media has been studied. We analyzed a wave motion suffering dissipation by the Joule effect in its propagation in a medium with global disorder. We solved the stochastic telegrapher's equationin the Fourier-Laplace representation allowing us to find the space penetration length of a plane wave in a complex conducting medium. Considering fluctuations in the loss of energy, we found a critical value k_{c} for Fourier's modes, thus if |k|<k_{c} the waves are localized. We showed that the penetration length is inversely proportional to k_{c}. Thus, the penetration length L=k_{c}^{-1} becomes an important piece of information for describing wave propagation with Markovian and non-Markovian fluctuations in the rate of the absorption of energy τ^{-1}. In addition, intermittent fluctuations in this rate have also been studied.

Lasing mode manipulation in a Benz-shaped GaN cavity via the Joule effect of individual Ni wires

Silicon-based gallium nitride lasers are considered potential laser sources for on-chip integration. However, the capability of on-demand lasing output with its reversible and wavelength tunability remains important. Herein, a Benz-shaped GaN cavity is designed and fabricated on a Si substrate and coupled to a Ni metal wire. Under optical pumping, excitation position-related lasing and exciton combination properties of pure GaN cavity are studied systematically. Under electrically driven, joule thermal of Ni metal wire makes it easy to change the temperature of the cavity. And then, we demonstrate a joule heat-induced contactless lasing mode manipulation in the coupled GaN cavity. The driven current, coupling distance, and excitation position influence the wavelength tunable effect. Compared with other positions, the outer ring position has the highest lasing properties and lasing mode tuning abilities. The optimized structures demonstrate clear wavelength tuning and an even mode switch. The thermal reduction of the band gap is identified to account for the modification of the lasing profile, but the thermo-optic effect is non-negligible under a high-driven current.

Experiments of convective evaporation of refrigerant R513A in a horizontal stainless-steel tube

Refrigerant R513A represents an interesting solution for the retrofit of conventional high-GWP fluorinated gases, such as R134a, R401A, R401B and R409A for low and medium temperature applications. R513A is an azeotropic mixture (almost zero-temperature glide at any operating pressure) made up of R134a and R1234yf (44% and 56% in mass, respectively), allowing at the same time a very low GWP of 580 and favourable safety characteristics such as no flammability and no toxicity (A1 ASHRAE class). The boiling performance of this blend is scarcely explored and studied in scientific literature, especially in case of commercial tubes typically adopted for refrigeration purposes. For this reason, this paper presents two-phase flow boiling experiments of refrigerant R513A in a 6.00 mm horizontal stainless-steel tube. Heat is provided by means of Joule effect directly on the tube surface, and the peripheral average heat transfer coefficients are obtained by measuring the temperatures at four sides (top, bottom, left and right) of the channel. The effect of the operating conditions is experimented and discussed, by varying the mass flux between 150 and 300 kg/m2 s, saturation temperature between 20 and 50°C and imposed heat flux between 5 and 20 kW/m2. Also, a comparison with the boiling performance of refrigerant R134a is proposed within the same operating conditions. Finally, the assessment of well-known flow boiling prediction methods is presented and discussed.

Numerical investigation of upward supercritical water flow with Joule heating effect

By using Joule's Law, resistivity equation, Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) functions, and resistivity-temperature correlation established based on the available experimental data, Joule heating heat flux profiles of upward supercritical water heat transfer in the annular tube are modelled and applied as the boundary condition. The calculated wall temperature result is compared to the Razumovskiy et al. experiment dataset. It is discovered that by using the PCHIP-modelled Joule heating profiles, the estimated wall temperature for both the Normal Heat Transfer (NHT) and Deteriorated Heat Transfer (DHT) regimes is comparable to the experiment in terms of trend and magnitude. However, by using the conventional constant heat flux profiles, the upstream and downstream wall temperatures are overestimated and underestimated respectively. This study demonstrated that CFD can adequately replicate experimental heat flux conditions, hence improving CFD estimates of supercritical heat transfer, particularly for the DHT, which has a substantial heat flux variation. With this fine imitation of the Joule heating heat flux, the critical DHT regime can be more accurately predicted.

Study of the correlation between electric and mechanical/thermal parameters in a graphite - LiFePO4 pouch cell

The correlation of thermodynamic parameters with the commonly studied electric parameters in grahite/LFP lithium-ion battery cells is thoroughly analyzed. From the comparison of stored charge, incremental capacity peak intensity and position and state of health against pressure it was revealed that there is a strong connection between pressure and peak intensity. The evolution of cell pressure with cycles justifies this relation, however, the cell temperature obeys the joule effect following the current variations. An almost linear dependence of pressure on state of charge, for 1 C current rates, throughout the scale presents a more accurate means of state of charge determination. In a first approximation, using a linear behavior, the variation of the normalized pressure with state of charge has been found to follow a slope of 0.67 in the first part of charging and 0.36 in the rest part of charging. By correlating the pressure to stored capacity a 0.294 kPa of pressure increase for every mAh of capacity loss has been determined which is translated in terms of state of health to a mean of 0.01 kPa for each 1% drop in cell health. Furthermore, signs of potential deterioration of cell performance could be reflected on pressure data as early as 140 cycles earlier than the generally accepted 80% end of life limit.

Durability of Joule effect of 3D printed carbon black/polylactic acid: Electrical cyclic tests and analytical modelling

The reliability of electro-induced heating of shape memory polymers is an issue to be considered in the development of 3D printed actuators. In this paper, the influence of electrical cyclic loading on the thermal behaviour and the microstructure of 3D printed samples made of polylactic acid filled with carbon black particles is analysed. The optimisation of the electrical conductivity through printing parameters and predictive analytical modelling are also conducted. Three different values of voltage are compared (20 V, 25 V and 30 V), showing that the higher the voltage, the higher the temperature within the samples and the faster the heating and cooling rates. It is also demonstrated that, after ten electrical cycles, for high voltages, the crystallinity ratio of the material increases, leading to a better conductivity of the sample. However, the possible consequences of these microstructural modifications on the mechanical behaviour must also be considered in the design of a 4D printed device in order to find the best compromise.

Study of finfet transistor: critical and literature review in finfet transistor in the active filter

For several decades, the development of metal-oxide-semiconductor field-effect transistors have made available to us better circuit time and efficiency per function with each successive generation of CMOS technology. However, basic product and manufacturing technology limitations will make continuing transistor scaling difficult in the sub-32 nm zone. Field impact transistors with fins were developed. offered as a viable solution to the scalability difficulties. Fin field effect transistors can be made in the same way as regular CMOS transistors, allowing for a quick transition to production. The use of inserted-oxide FinFET technology was presented as a solution to continue transistor scaling. Due to gate fringing electric fields through the added oxide (SiO2) layers, the electromagnetic integrity of an iFinFET is superior to that of a FinFET. We discovered that the proposed mobility model functions admirably and that the Joule effect mostly influences the drain current and the heat source. The major goal of this work is to compare the performance characteristics of combinational logic using CMOS and FinFET technology. The inverting gate is modelled in HSPICE simulation on a 32nm transistor size utilising CMOS and FinFET structures, and respective performances, such as energy consumed, are examined.

Extreme mechanical tunability in suspended MoS2 resonator controlled by Joule heating

Nanomechanical resonators are built into phones, as filters or accelerometers, but they lack a knob to effectively tune the frequency at the nanoscale when it’s easy to tune on an octave the tone of a classical musical instrument like a guitar string. Moreover, the control of deformation in nanomaterials, as two-dimensional (2D) materials, to tailor their electronic properties, i.e., straintronic, opens up avenues for applications in force detection, bolometry or quantum emitters. An accurate control of the deformation within these materials is thus necessary to fully exploit their potential. The precise study of deformations in 2D materials involves measurements of vibration modes and nanomechanics. By using a suspended MoS2 membrane heated by the Joule effect, we induce a strong softening of the mechanical resonance frequency as a function of the electrothermal heating, over one octave. A simple electrical tension is used to modulate the thermal mechanical tuning. Its amplitude is very large, greater than 100% modulation for one volt, compared to other approaches on 2D or 1D materials and, moreover, a very wide frequency range is accessible. Finally, we have related a photo-induced softening of the membrane over very long times with the current measurements and a photothermal effect.

Gallium-doped MXene/cellulose nanofiber composite membranes with electro/photo thermal conversion property for high performance electromagnetic interference shielding

With the rapid development of science and technology, information security and multiscenario applications of electronic equipment have received increasing attention in recent years. Therefore, the design and development of multifunctional electromagnetic interference shielding materials are key to solving the current development needs of electronic equipment. Based on the above topics, multifunctional liquid metal gallium (Ga)-doped transition metal carbides/nitrides (MXenes)/cellulose nanofiber (CNF/MXene@Ga, CMG) composite membranes with a nacre-like “brick–mortar” layered structure were synthesized using an ultrasonic probe and vacuum-assisted filtration. By optimizing the design, the CMG composite membranes could achieve a tensile strength of 36.12 MPa with good flexibility and could achieve a maximum thermal conductivity of approximately 9.11 W/m·K. The heterogeneous interface between MXenes and Ga nanoparticles and the intercalation of Ga nanoparticles significantly influenced the composite membranes for the absorption of electromagnetic waves, which yielded a specific shielding effectiveness per unit volume (SSE/t) of 6444.1 dB·cm2·g−1; this value is over the vast majority reported in the current literature. Further studies confirmed that the CMG composite membranes possessed excellent electrothermal and photothermal conversion functions. The electrothermal conversion agreed with Joule's law. Moreover, the phase transition behavior of Ga also imparts the membranes with the ability to store heat. The photothermal conversion ability was attributed to the surface plasmon resonance effect of Ga. Therefore, this work provides material support for the information security and multi-scenario applications of electronic equipment.

Consolidation and Forced Elasticity in Double-Network Hydrogels.

This paper discusses two observations that are unique with respect to the mechanics of double network (DN) hydrogels, forced elasticity driven by water diffusion and consolidation, which are analogous to the so-called Gough-Joule effects in rubbers. A series of DN hydrogels were synthesized from 2-acrylamido-2-methylpropane sulfuric acid (AMPS), 3-sulfopropyl acrylate potassium salt (SAPS) and acrylamide (AAm). Drying of AMPS/AAm DN hydrogels was monitored by extending the gel specimens to different stretch ratios and holding them until all the water evaporated. At high extension ratios, the gels underwent plastic deformation. Water diffusion measurements performed on AMPS/AAm DN hydrogels that were dried at different stretch ratios indicated that the diffusion mechanism deviated from Fickian behavior at extension ratios greater than two. Study of the mechanical behavior of AMPS/AAm and SAPS/AAm DN hydrogels during tensile and confined compression tests showed that despite their large water content, DN hydrogels can retain water during large-strain tensile or compression deformations.

Internal temperature distribution in lithium-ion battery cell and module based on a 3D electrothermal model: An investigation of real geometry, entropy change and thermal process

The temperature of lithium-ion cell and module has a significant impact on performance and ageing. Therefore, it is crucial predicting the temperature distribution and evolution of lithium-ion batteries. However, most of the electrothermal models consider a simplified cell geometry. In this work, a 3D electrothermal model of prismatic cells is developed based on the internal geometry reconstructed from tomography. The numerical results for one single cell and a module of 12 cells in series (12S) are compared to experimental measurements for charge and discharge at different current-rates (C-rates). This study shows a cooling process due to entropy change at low C-rate while at higher C-rate the Joule effect is predominant. The real cell geometry highlights the non-uniform temperature distribution induced by the inert gas and anisotropic thermal conductivity of the jelly roll. Finally, higher internal temperatures are observed in the module because of its architecture.