Search

Joule heating electrodes (JHEs) are required for thermal actuation systems. A highly stretchable, patternable, and low-voltage operating JHE based on hybrid layers of silver nanowires and carbon nanotubes are reported. The conductive layers are applied on a locally pre-strained bistable electroactive polymer (BSEP) membrane to form a wrinkled conductive surface with a low resistance of 300 Ω/sq, and subsequently patterned to a serpentine trace by laser engraving. The resistance of the resulting JHE electrode remains nearly unchanged up to 80−90% area strain. By applying a voltage of 7 − 9 V to the electrode, the temperature of the BSEP membrane increased to ~60 °C, well above the polymer's phase transition temperature of 46 °C, thereby lowering its modulus by a factor of 103. An electronic Braille device based on the JHEs on a BSEP membrane is assembled with a diaphragm chamber. The electrode is patterned into 3 × 2 individually addressable pixels. Through Joule heating of the pixels and local expansion of the BSEP membrane using a pneumatic pressure, the pixels deformed out of the plane by over 0.5 mm to display Braille letters. The Braille content can be refreshed for 20 000 cycles at the same operating voltage.

This study examines the molecules motion influences and thermal attributes in power-law non-Newtonian dissipative fluids' magnetohydrodynamic behavior, Joule heating, electromigration, and Cattaneo-Christov effects. Effects of Hall on both flow velocity and temperature, as well as the heat transport are considered. The investigation looks at heat transference that occurs when there is a slippage consequence, how the temperature influences the viscosity of the fluid, and how the potential parameters influence the exponential non-Newtonian flow of fluid via an extensible sheet. Runge-Kutta-Fehlberg's approach, which is based on the shooting procedure, was used to develop computational solutions for nonlinear ordinary differential equations. When exposed to a deformation that is generated by expansion, pressure, or agitation, a dilatant fluid is characterized by a phenomenon in which its viscosity rises and may harden. This phenomenon is referred to as the dilatation phenomenon. High shearing rates provide the impression that it is stable. When expanded, subjected to pressure, or agitated, dilatant fluids become more viscous and transform into solids. Both the non-equilibrium that occurs within the fluid and the reduction of the irreversibility processes that occur within it are caused by the acquired charges that are a result of Hall effect of fluid molecules.

This study aims to investigate the Joule effect, thermal radiation, and Coriolis effects in unsteady magnetohydrodynamics (MHD) micropolar flow over a 3-D unstable sheet. A magnetic field is typically applied to the surface; additionally, it is assumed that the fluid is conducting electricity. Other micro-rotations are also considered. The physical issue is resolved with the help of the fundamental equations, and the issue's complexity is reduced with the use of similarity variables. In the present approach, the homotopy analysis method (HAM) is employed. The heat, skin's friction factor, temperature, micro movements, and velocity associated with the emerging parameters and transfer rates are considered. The boundary layer thickness is increased as the parameter of vorticity increases. When the magnitude of the magnetic field increases, the skin friction coefficient decreases. The state variables are approximated up to six decimal places numerically. The numerical values of −f″(0) and −θ′(0) are computed to higher decimal places and compared with the available literature to validate the results. The outcomes obtained are compared with the available literature; the results here are corroborated, and the performance of the HAM is demonstrated.

The present study is carried out to investigate the effects of shape factor nanoparticles on the oscillatory MHD flow of a nanofluid in two immiscible liquids in a horizontal porous channel with velocity and thermal slip on the walls. Thermal radiation, Joule heating, viscous and Darcy dissipations have been accounted for in the model. We have considered and as nanoparticles, in the lower region (Region-I) and upper region (Region-II) respectively, with water as a base fluid. The effective ratio of thermal conductivity of the nanofluid is evaluated using the Maxwell-Garnetts model. Graphical behavior of velocity, temperature, and rate of heat transfer distributions have been depicted for the cases of slip and no-slip effects. This study has been made to understand the impact of different nanoparticle shape factors on temperature and heat transfer rate. For various parameters, values of shear stress distribution at the walls and the mass flux are shown in tabular form. Our study asserts that with the increase of the strength of the magnetic field, the velocity of the liquid falls and enhances the temperature of the liquid. The influence of different combinations of nanoparticles, on the flow variables, have also been discussed. In order to validate the analytical results, the numerical evaluation of the closed-form results, for the velocity distribution, has been compared with those of the numerical method, by using the NDSolve command in MATHEMATICA, and a good agreement is observed.

A scalable approach for manufacturing highly stretchable thermochromic wrapped yarns has been reported previously. Herein, the effects of twist-related technological parameters, namely, wrapping density and outer-inner twist ratio are investigated and have been optimized by technique for order preference by similarity to ideal solution (TOPSIS). The results indicate that the preparatory twist-related parameters have a remarkable effect on the spiral geometrical configuration of yarn constituents, and thus in turn influencing the final tensile and elastic properties of wrapped yarns. The wrapping density of 800 T·m−1 and outer-inner twist ratio of 1.25 were considered as the optimal alternative using TOPSIS. Moreover, a negative relation between voltage and color-changing time of yarn spun with optimal parameters was established. It was also found that the color of yarn above elevated triggered voltages always switched from purple to pink but followed different color-changing paths. More importantly, thermochromic response of yarn is insensitive to the applied strain.

Abstract 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.

Highly stretchable thermochromic wrapped yarns, which employ elastane filament (EF) as core, stainless steel wire, and thermochromic polyester filament as the first and second winding, was prepared, and the effect of elastane draft upon yarn properties was investigated. It was found that the elastane draft played an essential role in determining the final yarn behavior, and the optimized elastane draft parameter was 2.5 using Technique for Order Preference by Similarity to Ideal Solution. It is a distinctive configuration of yarn’s constituents and the EF draft that are responsible for the exceptional stretchability of yarns, and it showed mechanical robustness following cyclic stretch. Importantly, the yarn exhibited rapid, durable, and reversible color conversion when subjected to cyclic voltage, cyclic abrasion, and alkali. Finally, a flower-shaped pattern was fabricated by embroidering yarn onto an elastic substrate as a proof-of-concept, and no obvious variation of color fidelity was observed during the stretch.

This study investigates the steady, incompressible MHD flow of a hybrid nanofluid over a vertical solid cone embedded in a porous medium under suction effect. The research explores the effects of various factors, such as thermal radiation, chemical reactions, heat generation, viscous dissipation, and Joule heating on heat and mass transfer phenomena. To investigate the effects of hybrid nanoparticles, we consider single-walled carbon nanotubes (SWCNT) and alumina (Al2O3) along with water (H2O) as the base fluid. After a suitable similarity transformation, the governing equations are reconstructed and solved using the Keller-box numerical scheme. We present graphical and tabular analyses of various parameter impacts on heat transfer profiles and coefficients. This study provides valuable insights into the control of fluid dynamics and heat transfer in porous media, which have significant implications for industrial and engineering applications. The findings of the current article are in excellent agreement with previously published works. [ABSTRACT FROM AUTHOR]

This work mainly deals with the effect of heat, mass transmission, and heat generating (sinking) on the time-independent two-dimensional boundary-layer flowing of radiative MHD over a sheet, which is dwindling including Joule heating. The governing formulas have been converted into nonlinear ordinary differential equations (NLODE). The final step aims to obtain the graphical numerical illustrations from the set of NLODE; this method is namely as shooting using MATLAB. The accuracy of the outcomes from this study are examines and the comparison have been made by using bvp4c routine of MATLAB. The effect of different material factors on the flow speed, energy, and concentricity have been depicted in diagrams and tables and also discussed in detail. It is found that velocity is enhanced by increasing suction, whereas temperature is increased due to radiation, heat source/sink, and Eckert number. Meanwhile, concentration profile is always being suppressed by magnetic fields, suction, Schmidt number, and chemical reaction parameter. The streamline of the velocity is intensified at the region close to the dwindling surface, whereas the density is the highest for the thicker boundary layer thickness for the temperature and concentration streamlines. [ABSTRACT FROM AUTHOR]

The aim of this work is the preparation and the electrification of Ni_CeO 2 _Al 2 O 3 /OBSiC (Oxygen Bonded SIlicon Carbide) based foams used in two different endothermic reactions for H 2 production: methane steam reforming and ammonia cracking. In particular, the heating of the catalytic foams occurs by the Joule effect, and to guarantee a uniform temperature profile in both the axial and radial direction, two different heating resistances were used. In addition, the high tortuosity together with the very high thermal conductivity of the OBSIC carrier, allow to overcome the heat and mass transfer limitations achieving a better control of the reaction behavior. Wet impregnation method was adopted for the Ni and Ce deposition, while the final catalysts was characterized through Hg penetration technique, Scanning Electron Microscope (SEM), N 2 adsorption @77 K for the specific surface areas (SSA) determination and X-ray diffraction (XRD). The methane steam reforming and ammonia cracking tests were both carried out, in the same reactor, but at different space velocity values (WHSV). The results obtained are exciting, not only in terms of equilibrium approach and hydrogen production, but also in terms of energy consumption as kWh/Nm3 of H 2 produced. In particular, in the case of methane steam reforming the results showed an energy consumption E [kWh/Nm3 H 2 ] equal to 1.21 obtained at WHSV equal to 6.2 h−1, very close to the theoretical limit of 0.98 kW h/Nm3 H 2. Also, for ammonia cracking, the energy consumption was very promising considering the scale of our reactor, with 1.5 kW h/Nm3 H 2 obtained at a WHSV of 2.27 h−1, considering the theoretical limit equal to 0.71 kW h/Nm3 H 2. [Display omitted] • Joule heated structured catalyst on SiC foam as heat source for endothermic reactions. • Ni/CeO 2 –Al 2 O 3 -based catalyst was used for MSR and ammonia cracking reaction. • Good equilibrium approach was obtained for methane conversion and hydrogen yield. • The calculated energy consumption (kWh/Nm3) is very close to the theoretical limit value. • Nickel as an active species avoid the use of noble metals. [ABSTRACT FROM AUTHOR]

To predict the temperature profile in an ohmic reactor, it is essential to know the thermal and electrical conductivity of the reactor geometry. Those properties can be considered on different modeling scales: On the detailed (resolved) scale, the reactor consists of a packed bed structure, where the properties of each substance are considered. On the effective (continuum) scale, the packed bed is considered as effective medium with composite properties. In this contribution, we consider both scales and compare the results. Based on the detailed description with a resolved microstructure, the bed's effective thermal and electrical conductivity are computed. These properties are compared with analytical formulas. The electrical conductivity is the basis for the electrical field and the current density. Finally, these properties are used to evaluate the ohmic heating of the packed bed exposed to flow and to compute the temperature distribution within the reactor. [ABSTRACT FROM AUTHOR]

In this study, the electrical conductivity of PolyEtherKetoneKetone reinforced with five harness satin weave carbon fabric was measured. Induction heating experiments using a hairpin shaped coil were conducted on the same material. The study points out that the thermal response depends on the direction in which the eddy currents are generated in the laminate. The thermal response showed a linear relation with the measured in-plane anisotropic electrical conductivity, pointing towards Ohmic heating mechanisms being dominant during induction heating of the used material. This relation enables the accurate and efficient simulation of the induction heating of woven fabric reinforced composites, using only the electrical conductivity measured in one of the fabric's weave directions and in the fabric's 45° off-axis direction. [ABSTRACT FROM AUTHOR]

This work investigates the effect of Joule heating and viscous dissipation due to electric double layer (EDL) and electroosmotic effect on steady fully developed electromagnetohydrodynamic flow in a porous microchannel. Dimensionless formulations of the Poisson–Boltzmann, momentum, and energy equations are derived for the electric potential, velocity profile, and temperature distribution in the microchannel. Exact solutions for the temperature distributions and velocity profiles were obtained using the method of undetermined coefficients. The Debye–Hückel linearization is used to get an exact solution for the electric potential. The results showed that the Brinkmann number (Br) $({Br})$, Joule heating parameter (J) $(J)$, Debye–Hückel parameter (Κ) $({\rm K})$, Hartmann number (M) $(M)$, electric field (Ez) $({E}_{z})$, and suction/injection parameter (S) $(S)$ have a substantial impact on flow formation and heat transfer. Using MATLAB software, graphical simulations are provided to deliver a greater understanding of the influence of relevant parameters on the results achieved. [ABSTRACT FROM AUTHOR]

The development of the Internet of Things has increased the anticipation for wearable smart devices in personalized healthcare. Carbon aerogel films, characterized by multifunctional and lightweight porous properties, are emerging as promising components for lightweight smart devices. In this study, we adopt a straightforward, cost-effective approach to fabricate carbon aerogels using cellulose nanofibers (CNF) and graphene (GO) co-stabilized Pickering emulsion, followed by vacuum filtration, freeze-drying, and carbonization treatment. The carbonization process involves the pyrolysis of paraffin wax and the reduction of graphene oxide, resulting in a uniquely porous structure, low density, and remarkable properties related to Joule heating, photothermal conversion, and conductivity sensitivity across a wide range of stresses. Incorporating CRP-30 into a piezoresistive sensor enables real-time monitoring of subtle human activities such as carotid pulse beats, swallowing, and facial expressions. This multifunctional carbon aerogel film holds great promise in the domains of wearable personal thermal management and personal health monitoring. [ABSTRACT FROM AUTHOR]

The purpose of the current study is to evaluate the mass and energy transmission of a blood-based Casson Ferrofluid flow across a stretching cylinder. The consequences of the Casson parameter, cylinder curvature, thermal radiation, chemical reaction, and non-Newtonian viscous dissipation are also considered. The nanofluid flow phenomena are mathematically designed in the form of a system of nonlinear PDEs which are degraded and non-dimensionalized to the set of ODEs by using suitable similarity transformations. The homotopy analysis method has been applied to find out a semi-analytical solution for the nonlinear set of ODEs. The significance and physical behavior of flow parameters are graphically characterized versus the velocity, energy, and mass profiles. The numerical outcomes for Sherwood number, drag force and Nusselt number are also presented through Tables. A comparative evaluation has been done for validation purposes to authorize and justify the present results. From the tabular and graphical results, it has been noticed that the velocity profile lowers while the energy profile develops versus the variation of magnetic factor. The impact of curvature factor boosts the velocity and mass transfer rate of the Casson nanofluid while reducing the temperature curve. Furthermore, the consequences of the thermophoresis effect raise the temperature profile of the Casson Ferrofluid flow. [ABSTRACT FROM AUTHOR]

In many engineering systems, hybrid and nanofluids are influenced by their respective thermophysical characteristics. Lately, several models have been envisaged to foresee the hybrid and nanofluid attributes. The properties of hybrid nanofluids (HNFs) as potential heat transfer fluids are controlled by numerous aspects such as solid part size, volume fraction, and temperature. Considering the interesting facts of the hybrid and nanofluid flows, we in this exploration examined the thermal performance comparison of both types of fluid flows. The nanofluid and HNF are composed of molybdenum disulfide (MoS2)/kerosene oil and silicon dioxide–molybdenum disulfide (SiO2–MoS2)/kerosene oil, respectively. The flows are taken in a canonical gap between the cone and the disk. Both the cone and the disk may be rotating or stationary. The novelty of the computational model is enhanced by discussing the effects of viscous dissipation, Joule heating, and the variable thermal conductivity with convective condition. The Tawari and Das model is designed to analyze the heat transfer performance of the assumed fluid flows. The assumed fluid model is transmuted into the set of differential equations that are dealt numerically with the bvp4c MATLAB approach. The results are displayed in tables and graphical forms. For elevating estimations of the Eckert number, the heat transmission rate is found to be more significant in the disk than cone. It is also learned that hybrid nanoliquid heat transfer performance outperforms nanoliquid. The fluid velocity increases by raising the nanoparticle volume fraction ϕmol, and is decreasing for a higher magnetic field parameter. With the elevating estimates of thermal conductivity, it is shown that the cone transmits heat more quickly whereas the disc transmits heat more slowly. The thermal conductivity parameter increases the probability of collision of the liquid particles, that ultimately upsurges fluid heat transmission rate. [ABSTRACT FROM AUTHOR]

The recent research in hybrid nanomaterials brings multidisciplinary applications in enhancing the heat transfer phenomenon, engineering applications, cooling systems, energy generation, etc. The literature survey claims that various models for hybrid nanofluids are suggested with interaction of viscous materials. However, the decomposition of non-Newtonian hybrid nanofluids is more interesting and valuable in industrial and engineering processes. Based on such dynamical applications of non-Newtonian hybrid nanomaterials, current model endorsed the thermal assessment of decomposition of Williamson (non-Newtonian) hybrid nanofluid in complex wavy channel with assessment of various shape factors. The properties of base materials are discussed by glycerin liquid subject to the copper and aluminum oxide hybrid particles. The joule heating and magnetic force interferences are encountered. Furthermore, detection for interesting shape features like blades, platelets, cylinders and bricks are discussed. For creeping flow phenomenon, the modeling of problem is summarized by using the long wavelength assumptions. The shooting scheme is utilized for simulating the governing flow system. Physical properties of presented model are discussed with heat transport phenomenon. The contour plots and stream functions are presented. It is observed that the pumping and heat transfer coefficient reduces due to magnetic parameter. An enhancement thermal phenomenon has been predicted due to solid volume fraction. Furthermore, for heat transfer assessment is comparatively slower for bricks-shape nanoparticles as compared to blades nanomaterial. The obtained results present applications in the blood flow, heat pumping systems, medical images, angiography, pulse pumping, etc. [ABSTRACT FROM AUTHOR]

We examine the time-independent boundary layer flow (BLF) and heat transmission of Sisko fluid subject to convective boundary conditions. The fluid flow is impacted through a nonlinear stretchable sheet in the existence of a magnetic field and porous medium. Thermal conductivity effect assumed on heat transfer. We also consider the impact of Joule heating and radiation in the present study. The model's leading partial differential equations (PDEs) have reduced similarity transformation into nonlinear ordinary differential equations (ODEs). The resultant nonlinear coupled differential equations are tackled in MATLAB built-in solver (bvp4c). The repercussions of relevant parameters like material parameter (A) , the combined effect of the magnetic and porous medium parameter (C) , Sisko fluid power law index (n) , stretching parameter (r) , Prandtl number (Pr) , Joule heating parameter (J) , temperature parameter (λ) and radiation parameter (N R) on the temperature, velocity, skin friction coefficient, and Nusselt number are scrutinized via graphs. The results show that higher inputs of material parameter have a growing impact on velocity and a decreasing effect on temperature distribution. Increasing Sisko fluid has a reducing impact on velocity distribution. As witnessed from sketches, the shear stress distribution is decreased to increase the impression of the Sisko fluid, material, stretching, and combined parameters. Our computed outcomes are linked to existing outcomes and get the finest contract. The results benefit from comprehending the flow characteristics, flow behavior, and how to foresee it for individuals involved in designing high-temperature machinery in the industry. [ABSTRACT FROM AUTHOR]

This paper aims at developing non-similar solutions for heat transfer augmentation in ternary hybrid nanofluids. Nanofluid is composed of three distinct (Silver, Copper, Aluminum oxide) nanosize particles while water is considered as a base fluid. Darcy–Forchheimer expression with variable porosity and permeability is adopted. Joule heating and viscous dissipations are also considered. Non-similar approach is utilized. Numerical solutions are computed by bvp4c solver of MATLAB. Graphical illustrations for flow and thermal fields behavior are provided. Comparative results are obtained for ternary hybrid nanofluid and nanoliquid. Physical quantities such as skin drag coefficient and Nusselt number are computed and interpreted. Our results reveal that rate of heat transfer augments substantially for Ag/water nanofluid in comparison to other classes of nanofluid. [ABSTRACT FROM AUTHOR]

The main aim of this paper is to provide numerical simulation for viscous nanofluid by stretching cylinder using Buongiorno's model. Dissipation, Joule heating and magnetic impact with irreversibility analysis are examined. Furthermore, Brownian movement and thermophoresis diffusion effects are studied. Through constitutive relations, nonlinear equations are obtained. By adopting suitable variables, the partial differential equations are changed to ordinary differential equations. Entropy rate is calculated using thermodynamics second law. ND-solve technique in Mathematica is employed to tackle dimensionless ordinary differential equations. The behavior of flow controlling parameters is examined graphically. Physical quantities are discussed through tables. A decrement in velocity is seen through magnetic effect, while opposite impact is seen for entropy rate. A similar scenario is seen for thermal field through random and thermophoresis variables. Reduction in concentration is seen for reaction parameter and Schmidt number. Important findings are presented. [ABSTRACT FROM AUTHOR]

This work aims to examine the entropy production, heat transport, and dynamics of the unsteady thin film magnetohydrodynamic (MHD) flow of a nanofluid composed of alumina (Al2O3) and water. The fluid flow is seen to pass over an inclined sheet, taking into account the effects of buoyancy force, viscous dissipation, and joule heating. The system of partial differential equations (PDEs) is optimized under the boundary layer assumptions. Appropriate transformations are used to convert the governing partial differential equations (PDEs) and boundary conditions into dimensionless forms. Using MATLAB’s bvp4c code and a local non-similarity technique with up to second-degree truncation, we can obtain the findings of the enhanced model. The effect of multi-shape Al2O3 nanoparticles on flow, heat, and entropy-generating features is also investigated after the calculated results have been successfully aligned with published data. Mixed convection, nanoparticle volume percent, inclination angle, magnetic field intensity, mass suction, Eckert number, and Biot number are only a few of the governing parameters whose effects are graphically shown for selected values. As a result, the local Nusselt number and skin friction coefficient may be calculated. The skin friction and Nusselt number profiles exhibit a decreasing trend as the values of nanoparticle volume fraction (ϕ) magnetic (M) and unsteadiness (A) increase toward mixed convection (δ). On the other hand, Nusselt number profile increases with increasing values of mass suction parameter (S) The profiles of entropy generation and Bejan number show an upsurge as the values of the magnetic parameter (M) and Brinkman number (Br) increase. Conversely, the entropy generation reduces with an increase in the temperature difference parameter (Ω) and Bejan number increases. [ABSTRACT FROM AUTHOR]

The recent development in smart material-based actuators are composite structures of thin film integrated SMA/PI bimorph in the view of actuator cum sensing in electromechanical systems for medical, robotics, and aerospace application. The purpose of the present work on integrated SMA/PI bimorph is to reveal their ability to perform as actuators and sensors and study on control characteristics for soft robotic, positioning, and valve applications. Vide this research paper, the SMA bimorph actuator [thin film SMA (CuAlNi)/polyimide (Kapton) bimorph] is used as actuator cum sensor for position control. Proposed a Proportional Derivative combined Variable Structure Controller (PD-VSC) to control the displacement by Joule heating actuation in two ways, which are sensor-based control and self-sensing control. From the control characteristics in from of tracking and disturbance rejection, it is concluded that the integrated CuAlNi/Kapton bimorph can be successfully implemented for soft robotic, positioning, and valve applications. [ABSTRACT FROM AUTHOR]

With the rapid development of science and technology, multifunctional wearable devices have become a major trend in medical field. There is an urgent need to fabricate multifunctional materials with thermal insulation, mechanical flexibility, piezoresistance, and adjustable heating behavior to cope with the thermal management and health monitoring of human body in the harsh environment. To address this issue, three-dimensional melamine-based carbon foams (CMF) have been developed, with sericin-functionalized carbon nanotubes (CNTs) and in situ-grown carbon nanofibers (CNFs) in the CMF skeleton. The strategy of hierarchical porous micro-nanostructure enhanced the synergistic effect between CNTs and CNFs, resulting in exceptional resilience at 0–80 % compressive strain and cyclic stability at 20 % strain. Such carbon foam composites demonstrated excellent piezoresistive sensing performance, wide pressure range (0–20 kPa), high sensitivity (S = 0.11 kPa−1), and quick response (response/recovery time of 150/120 ms). They also showed good thermal insulation and Joule heating properties, particularly in presenting strain-dependent Joule heating mode at low voltage. Such amazing characteristics provide inspiration for temperature regulation of flexible, energy-efficient heating devices, and make them promising for smart sportswear, human-machine interfaces, and wearable medical devices. [ABSTRACT FROM AUTHOR]

These days, thermal power and industrial processing rely heavily on solar energy. This study examines the heat dispersion in Casson nanofluid flow across an expanding cylinder by considering nano aggregate kinematics. Ethylene glycol-Cu nanofluid is deemed to boost the heat transfer competence of parabolic trough collector (PTSC). A stable magnetic field is used in the radial direction in the appearance of asymmetrical heat source/sink, radiative, and Joule heats. A mathematical model was developed and resolved using the Keller-box approach. Results are deliberated through pictorial and numerical evaluations for aggregation and non-aggregation cases. The improvement of the thermal field caused by nanoparticle aggregation is proven. It is also found that the surface drag and thermal transfer rate can be controlled by increasing the Darcy parameter. [ABSTRACT FROM AUTHOR]

The axisymmetric stagnation point flow of brick and blade-shaped Silver and Copper nanoparticles immersed in an ethylene glycol base fluid under the influence of an induced magnetic field over an unsteady radial stretching surface is investigated in this study. The unsteady phenomenon is considered because most flow issues in practice are unsteady. The fundamental laws of mass, momentum, and energy conservation are used to present the physical model. Heat transmission is also examined under the effects of magnetohydrodynamics, Joule heating, viscous dissipation, and convective boundary conditions to give a realistic physical investigation. Scaling analysis transforms the flow-governing issue into a collection of higher-order nonlinear ODEs. These are, then, solved numerically using the fourth-order Runge–Kutta and shooting techniques. Moreover, the numerical technique is validated by calculating residual error. It is concluded that, compared to the Ag–EG nanofluid, the Cu–EG nanofluid had the highest IMF, lowest temperature, minimum surface drag, and maximum heat flux, making it the ideal choice for creating a radial module. [ABSTRACT FROM AUTHOR]

AbstractNumerically the hybrid nanofluid (HNF) flow comprised of aluminum alloys (AA7072 and AA7075) across to coaxial cylinders is reported in the current analysis. The fluid flow has been examined under the significances of viscous dissipation, thermal radiation, and exponential heat source/sink. The HNF is produced by the addition of AA7072 and AA7075 nanoparticles (NPs) in water. Aluminum alloys are mostly used for the electric module wrapping, electronic machinery, automotive body, solar and wind energy controlling, and energy generation. The flow has been modeled in the form of momentum, continuity, and energy equations. Numerical approach parametric continuation method (PCM) is used to solve the modeled equations. The consequences of flow and energy parameters on the temperature, velocity, skin friction, and Nusselt number have been revealed through figures. It has been noticed that the fluid velocity drops, whereas the energy curve develops with the escalating influence of magnetic field. Furthermore, the rising numbers of AA7072 and AA7075 NPs in the water diminish the fluid velocity and temperature profile. Energy curve accelerates with the growing values of Brinkman number. It can be observed that the energy transmission rate upsurges up to 13.17% by the addition of AA7072 and AA7075 NPs in the water. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Long‐time indoor exposure to electromagnetic waves generated by electronic devices has posed a threat to the health of young life. The threat may intensify in low‐temperature environments due to low immunity. Prolific endeavors have focused on developing electromagnetic interference (EMI) shielding materials but failed to meet the visible, portable, and temperature‐controllable indoor‐use requirements. Herein, a detachable and heatable AgNWs/PU composite film is fabricated by facile spray coating and quick melting. The half‐inserted 3D network structure of AgNWs on PU ensures stable and high conductivity, thus endowing sufficient EMI shielding performance at 27 dB for indoor use. The high transparency (≥73.2%) and strong electrostatic force enable the detachable and portable use of the composite film. The resulting Joule heat at the voltage of 5 V endows a heatable property, which raises to 44.8 °C within 60 s. The AgNWs/PU composite film can self‐adhere in an indoor protective chamber, enabling visual monitoring and blocking electromagnetic radiation while keeping a comfortable inside temperature. The facile fabrication makes the self‐adhesive and multifunctional film possible in large‐scale production for practical application. [ABSTRACT FROM AUTHOR]

In recent days, entropy generation has attracted the attention of several researchers due to its applications in manufacturing electronic devices, heat exchangers, conservation of energy, and generation of power. Further, activation energy is an essential requirement in automobile and chemical industries, nuclear reactors, and so on. This paper investigation aims to examine the entropy generation and the mass and energy transfer in the magneto-hydro dynamic movement of convective Carreau-Yasuda nano liquid past a porous stretching sheet with the consequences of activation energy, energy source, and binary chemical reaction. Also, the analysis of the impact of viscous and Joule dissipation in the presence of suction/injection into the Buongiorno model is an essential objective of this study. By introducing a similarity variable, the partial differential equations are altered into a system of ordinary differential equations. Numerical solutions to the modified equations are determined by utilizing a BVP5C MATLAB package. The findings are presented visually for several relevant flow characteristics and explained carefully. The thermophoresis parameter and activation energy parameter optimize the concentration of nanoparticles. These outcomes further indicate that as the larger Brinkmann and permeability parameters the entropy generation is broadened. It is discovered that an augmentation in thermal and solutal Grashof numbers is associated with greater velocity distribution. [ABSTRACT FROM AUTHOR]

The non-Newtonian characteristic of the fluid flow phenomena has several applications in industries and the production of engineering gadgets. Based upon the role, the present work deals with the flow of Williamson nanofluid past two inclined parallel sheets. Further, the influence of radiating heat due to thermal radiation, Ohmic heating because of the magnetization, and inclined angle on Williamson fluid are presented, which are vital for the heat transfer enhancement. The proposed study became novel due to the scrutiny of entropy for the irreversibility processes within the system that is obtained due to heat transfer. The designed model with dimensional form is developed by converting to dimensionless forms with the help of similarity transformations. The finalized transformed equations are handled analytically using the Homotopy perturbation method (HPM). Heat irreversibility is calculated by inserting the observed values into entropy generation and Bejan number. The suggested method of solution for the momentum profile is verified by comparing it to a previously published numerical result in some limited circumstances, and great agreement is found. The result reveals that the entropy generation is enhanced near the upper wall of the channel for the magnetized particle but thermal radiation attenuates it, however, the fluid temperature boosts up for the enhanced coupling constraint i.e. for the existence of Eckert number. [ABSTRACT FROM AUTHOR]

This investigation explores the convective MHD stagnation point flow of Casson nanofluid over a stretching sheet in a porous medium with higher-order chemical reactions and multiple slips. The examination of heat transmission is carried out in the presence of radiation, Joule heating, viscous dissipation, and heat source. The system of governing equations was simplified by using appropriate transformations. The transformed equations are tackled numerically by a Runge-Kutta-based shooting technique with the bvp5c MATLAB package. The graphical and numerical results for different parametric values are discussed and presented through figures and tables. It is observed that an increase in the magnetic field, porosity, and Casson fluid parameter reduces the velocity whereas the opposite trend is seen in the case of the thermal Grashof number and the solutal Grashof number. Increasing values of radiation and Joule heating parameters, and the Eckert number, lead to an increase in the temperature. The chemical reaction, suction, and solutal slip were found to reduce the concentration. The friction factor was reduced due to the higher values of the thermal Grashof number, solutal Grashof number, and the velocity ratio parameter. Also, an increase in the Brownian motion and thermal slip parameters decreases the heat transfer rate. The computational results of the Nusselt number have been validated with published results in the literature and found good agreement. The results obtained in this investigation have applications to biomedical, engineering, and industrial sectors such as food processing, polymer manufacturing, glass, and fiber production, improving oil recovery, and material processing. [ABSTRACT FROM AUTHOR]

Abstract 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 $$_{2}$$ 2 O $$_{3})$$ 3 ) 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 $$_{2}$$ 2 O $$_{3}$$ 3 /H $$_{2}$$ 2 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.

A metallic alloy is a combination of two or more elements, often called a compound or a solution. Steel is largely composed of carbon, a nonmetal, but alloys are often made up of metals. In this article, the authors have explored the electrically conducting water-based viscous nanofluids flow past a rotating disk surface. The nanofluids flow is composed of titanium and aluminum alloys where water is used as a base fluid. Two important cases, namely the stretching case and the shrinking case, were investigated to analyze the flow behaviors due to the different embedding factors. The impacts of viscous Joule heating, thermophoresis, Brownian motion, activation energy, nonlinear thermal radiation, and chemical reaction are investigated here. By employing an appropriate set of variables for shifting the leading equations to dimension-free form. The mathematical model is solved numerically by incorporating the bvp4c MATLAB scheme. Current work is validated with previous studies. The outcomes showed that the radial velocity increases when the disk surface stretches and reduces when the disk surface shrinks. On the other hand, the Azimuthal velocity increases when the disk surface shrinks and reduces when disk surface stretches. Both the radial and Azimuthal velocities are the diminishing functions of the magnetic factor, whereas temperature is the growing function of magnetic factor. In addition, the temperature is more influenced by the magnetic factor in the case of nonlinear radiation. The higher magnetic factor increases skin friction. In addition, the stretching case experiences more surface drag than the shrinking case. It is found that nanofluid flow containing titanium alloy has perceived the greater impacts of the embedded factors compared to the nanofluid flow containing aluminum alloy.

The inclusion of nanoparticles has the potential to improve the thermal efficiency of the base fluid. The field of nanofluid (NF) dynamics has attracted important attention due to its extensive range of practical uses like fuel cells, solar energy, medication administration, heat transfer, microfabrication, coolant applications, and other related domains. The aim of this study is to scrutinize the impact of Lorentz force, thermal energy, joule heating, heat source and injection parameters, and Brownian and thermoporetic diffusions on the hybrid nanofluid over the moving wedge. The stability inquiry is reported for the existing work in order to confirm the stable solutions that make the study unique. Novelty of the existing work is to investigate the hybrid nanofluid flow and its stability. The nanoparticles MoS2 and Ag are suspended in ethylene glycol and water used as host fluids. The numerical solution is obtained from the dimensionless first-order differential equations, which are achieved from the basic flow phenomena through similarity alteration variables. The influence of emerging factors on flow phenomena is reported via graphs. The positive eigenvalues report stable solutions, while the negative eigenvalues designate unstable solutions. It is perceived that due to Lorentz force, the rate of the fluid declines while the temperature inside the flow channel enhances. The velocity profile decreases while the temperature and concentration increase with increasing quantities of permeable factors. Similarly, the Forchheimer number causes to enhance the flow rate and decrease the heat and concentration outlines. The current analysis is validated by the published work.

This article documents the hydro-magnetic, incompressible Jeffery-Hamel flow in convergent/divergent (CD) channels with stretchable walls. Although there seem to be several works on the subject in the available literature, only a few attempts have been made to work into mass and heat transfer analysis. Consequently, novelty of present study is to investigate the significance of Soret/Dufour. Joule heating, and chemical reaction effects on Jeffery-Hamel flow. The governing coupled system of PDEs showing the mathematical framework of the current physical problems is converted into ODEs through proper transformations. The numerical solution of the obtained couple of ODEs is simulated with the assistance of Mathematica-11 solver NDSolve. The computed outcomes depict that Lorentz force developed due to the magnetic field decays the fluid motion for both convergent and divergent channels. Furthermore, incorporating the heat source and Dufour effects yields a sustainable increase in temperature distribution, whereas the Soret number has reverse features on concentration. Furthermore, the numerical outcomes reflect the significant variation in Nusselt number against magnetic, radiation parameter and Soret number.

Ball Grid Array (BGA) packaging method has been widely used in microelectronic devices, and electromigration (EM) in BGA is a crucial reliability issue, determining the performance of the products. Herein, we report a new failure mode induced by a coupling effect of EM and Joule heating in BGA structure. The test sample consists of a roll of 500 μm-BGA solder joints with upper and lower Cu under-bump-metallization (UBM) of different thicknesses, 16 μm, and 68 μm, respectively. Open failures of the thinner cathodic Cu UBM at the contacting area with solder joint were observed under four different EM conditions (130 °C-3000 A/cm2, 160 °C-2300 A/cm2, 160 °C-3000 A/cm2, and 160 °C-4600 A/cm2). Infrared (IR) results reveal the temperature at the thinner Cu UBM is higher than that in the solder joint as well as at the thicker Cu UBM. Simulation results elucidate the current density at the contacting area is about 22 times higher than the average density in the solder joint, so the effect of current crowding can be very serious in the failure site. Furthermore, severe current crowding and Joule heating promote the nucleation rate of voids at the joint location, which can further increase the current density and temperature, leading to a positive feedback effect until an open failure occurs in the circuitry. Our analysis enables the discussion of a coupling failure mode of EM and Joule heating in BGA, and provides a valuable guide of device design against EM failure in consumer electronic products.

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 (AA 7072) 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 (AA 7072) 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% when h = 0.5. Also, the heat transfer rate is reduced 18.71% and 16.70% when h = 0.5% and R p = 1.5. In fact, the present results are compared with the published results and they met good agreement. [ABSTRACT FROM AUTHOR]

In this article, the impact of Joule heating on the thermal performance of Williamson nanofluid is analyzed under the influence of viscous dissipation along with the Joule heating. Also, the flow is subjected to Thompson and Troian slip conditions that directly influence the velocity of the flow at the boundary. Meanwhile, to achieve the even distribution of nanoparticles in the nanofluid, gyrotactic microorganisms are dispersed whose motion is due to the virtue of density gradient. The heat conduction at the surface is governed by the convective condition which allows the interpretation of the Biot number. The mathematical model is constructed employing these presumptions using partial differential equations, which are then subsequently reduced using similarity transformations to get the ordinary differential equations (ODEs). The RKF-45 numerical approach is used to solve the nonlinear ODE system thus acquired, and the findings are validated by comparing them to the previously published works. The results of this study showed that the higher values of thermophoresis and Brownian motion parameters cause more heat conduction. Also, the rise in the Eckert number that relates to the internal friction enhances the temperature conducted by the nanofluid. Meanwhile, the Lorentz force helps in controlling the flow velocity. [ABSTRACT FROM AUTHOR]

The purpose of this study is to provide a mathematical model of the process of entropy formation that occurs during the MHD convective transport of Carreau fluid across a curved stretched surface with soret and dufour effects. The energy equation is explored with the combined characteristics of joule heating, viscous dissipation and heat absorption/generation. The modeled governing equations are converted into nonlinear ordinary differential equations using similarity variables, and the results are acquired through the utilization of the built-in command NDSolve. It is revealed that entropy generation and Bejan number increase for higher values of Brinkman number. The impact of the Hartman number increase the entropy generation and reduced the Bejan behavior. The curvature parameter reduced the flow and temperature of fluid but increased the concentration profile. A small change in the heat absorption parameter strengthens the temperature profile. Graphical representations are used to discuss the behavior of Bejan number, entropy generation, velocity, temperature, and concentration profiles for the different values of physical parameters. The results of computations of drag force, the local nusselt number, and the Sherwood number are shown in tabular form for numerous values of the parameters. [ABSTRACT FROM AUTHOR]

An exact similarity solution is worked out for fluid motion in the vicinity of a cylindrical surface in an electrically conducting viscoelastic fluid obeying the Jeffrey model. Cylindrical surface expands axially with linear velocity and has a prescribed surface temperature. The present analysis focuses on the partial slip assumption which gives rise to a nonlinear case Robin-type (mixed) boundary condition in axial velocity. In contrast to a previously published study (J. Mech., vol 31, pp. 69–78, 2015) which only reported local similarity solutions in no-slip case, the present work provides an exact similarity analysis by defining a quadratic surface temperature. The effects of the magnetic field and Joule heating on the momentum and thermal transport phenomena are also scrutinized. A numerical routine is used to solve the equation accurately for a wide range of fluid parameters, including ranges that could not be handled by previous approximate analytical methods that were limited to the no-slip limit. The influences of viscoelasticity and partial slip on the flow behavior are investigated, and the coefficient of skin friction for a Jeffrey fluid is calculated. Obtained results are consistent with the previously published works under special situations. The case of flat surface, which can be obtained as a limiting case of the model, is not even explored in the past. [ABSTRACT FROM AUTHOR]

In this piece of communication, a theoretical investigation of two dimensional boundary layer flow of Magnetohydrodynamics (MHD) Carreau nanofluid axisymmetric flow past unsteady radially stretching porous disk is made. The investigation includes the effects of viscous dissipation, Joule heating, thermal radiation, suction/injection, Darcy–Forchheimer porosity model and binary chemical reaction with activation energy, etc. To examine the impacts of the aforementioned effects, the conservation laws are formulated with strongly nonlinear partial differential equations (PDEs), which are then transformed into a system of initial value problems (IVPs) using appropriate similarity transformations and techniques. The 5th order Runge–Kutta with the shooting technique is used to find numerical solutions aided by Python programming with built in program “fsolve”. The method is validated with other published articles under common assumptions and it agrees nicely. The impacts of the pertinent parameters on velocity, temperature, concentration, skin friction coefficient and the rates of mass and heat transfers with in the flow regime are displayed using graphs and tables. The main outcomes include the motivation of local Nusselt and Sherwood numbers for shear thickening (n=1.5) than shear thinning (n=0.5) cases of the Carreau nanofluid. The momentum boundary layer of the Carreau nanofluid gets thinner with an increase in Forchheimer number, unsteady and suction parameters. A dual nature is observed for concentration of the Carreau nanofluid with a rise in Eckert number, i.e increasing in concentration around the wall and decreasing far away from the wall. The rise in destructive and constructive chemical reaction parameters disperse and accumulate the concentration of the system, respectively.

The study of an inclined stretching cylinder in a porous medium holds significant implications for understanding complex fluid dynamics and heat transfer phenomena, mainly when influenced by a hybrid nanofluid containing Cu and Al2O3, Joule heating, and a magnetic field in the presence of Williamson fluid. The nonlinear ordinary differential equations are derived by applying pertinent similarity transformations to partial differential equations. Subsequently, these non-dimensional ordinary differential equations are transformed into a system of first-order ODEs and numerically solved using Maplesoft's symbolic computation software MAPLE 2023. The influence of governing parameters on dimensionless velocity, temperature, concentration, skin friction, heat, and mass transfer rates is investigated. This investigation is crucial for various practical applications, including geothermal reservoirs, enhanced oil recovery, and environmental processes involving porous media. It is demonstrated that Biot and Eckert numbers and nanofluid parameters contribute to increased surface temperature, while the Lewis number leads to a decrease in dimensionless concentration. Moreover, the curvature parameter is associated with an increase in dimensionless concentration, and skin friction demonstrates a direct relationship with the magnetic parameter while inversely correlating with the cylinder's curvature.These results contribute to the scientific understanding of these complex interactions and provide valuable insights for engineering applications, such as designing efficient heat exchangers, optimizing cooling systems, and advancing technologies involving fluid flow and magnetic fields.

Abstract Joule heating is one of the main energy inputs into the thermosphere‐ionosphere system. Precise modeling of this process is essential for any space weather application. Existing thermosphere‐ionosphere models tend to underestimate the actual Joule heating rate quite significantly. The Thermosphere‐Ionosphere‐Electrodynamics General‐Circulation‐Model applies an empirical scaling factor of 1.5 for compensation. We calculate vertical profiles of Joule heating rates from approximately 2,220 hr of measurements with the EISCAT incoherent scatter radar and the corresponding model runs. We investigate model runs with the plasma convection driven by both the Heelis and the Weimer model. The required scaling of the Joule heating profiles is determined with respect to the Kp index, the Kan‐Lee merging electric field EKL, and the magnetic local time. Though the default scaling factor of 1.5 appears to be adequate on average, we find that the required scaling varies strongly with all three parameters ranging from 0.46 to ∼20 at geomagnetically disturbed and quiet times, respectively. Furthermore, the required scaling is significantly different in runs driven by the Heelis and Weimer model. Adjusting the scaling factor with respect to the Kp index, EKL, the magnetic local time, and the choice of convection model would reduce the difference between Joule heating rates calculated from measurement and model plasma parameters.

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.

Abstract Superhydrophobic surfaces are known to resist diatom and bacteria adhesion if stable air layers are formed underwater (known as a plastron). However, most preparation techniques to obtain superhydrophobic surfaces need sophisticated chemical treatments and/or complicated chemical procedures. Here a 3D printing technique is used to create different molds for polymer casting. A conductive graphite‐carbon black‐silicone composite mixture is developed to fabricate different polymer surface casts from these molds. The obtained surfaces exhibited contact angles >145°, which led to a plastron formation on the surfaces underwater, and areas with intact plastrons protected the samples from diatom attachment. Due to the conductivity of the coatings, it is possible to replenish the plastrons by heating the surfaces.

This study investigates the thermal energy and reactive processes on nanomaterial flow via convergent/divergent channels. The research looks at how varied channel designs, fluid characteristics, and operating conditions affect flow patterns, temperature distributions, and heat transfer rates. The study focuses on the heat transfer mechanisms within the channels and the effect of exothermic/endothermic reactive processes on fluid flow and temperature profiles. The findings provide vital insights into the behavior of such flow systems, aiding in the comprehension of heat transfer phenomena and prospective applications in engineering domains such as energy systems, chemical processes, and aeronautical engineering.

In this study of the nanofluid flow in a channel, the power of the magnetic field has been introduced to the momentum and energy equations as an innovative development. The impact of heat transfer due to free convection has also been considered. Nanofluid modeling has made use of Buongiorno's model. The similarity solution was used to transform the governing equations of the problem into ordinary differential equations, which were then solved using the finite element method (FEM). Investigations have been done into how several factors, such as the Hartmann number, Eckert number, Brownian number, Thermophoresis, and Lewis number, affect the profile of velocity, temperature, and concentration. Results indicate that the reduction in the dimensionless maximum velocity increases by 10.7% from Ha = 0 to Ha = 5, 23.5% from Ha = 5 to Ha = 10, and 48.4% from Ha = 10 to Ha = 20. Also, the Joule heating effect is prominent, as evidenced by a significant increase in the dimensionless maximum temperature from Ha = 0 to Ha = 20, reaching a rise of 540.3%.

Variations in viscosity and thermal conductivity play a vital role in the manufacturing of glass fiber, ceramics, pharmaceuticals, and plastics, as well as in hot rolling, space technology, and high-temperature processes. This article investigates an electrically conducting hybrid nanofluid flowing across an exponentially extended sheet under variable fluid properties, such as thermal conductivity, viscosity, and non-uniform heat generation. In addition, the Prandtl number can vary inside the boundary layer and is an effective way to manage heat transfer and fluid flow. Furthermore, slip effects and suction at the boundary have been considered, and the hybrid nanofluid flow is also influenced by variations in viscous forces and viscous dissipation effects. The governing partial differential equations can be discretized into dimensionless ordinary differential equations using similarity transformations. The various important physical parameters have been presented in detail using diagrams. It is also observed that the skin friction of hybrid nanofluids is increased by up to 4.07% compared to nanofluids with suction. The presence of thermal radiation can enhance the energy Nusselt number of hybrid nanofluids by as much as 6.5%. Moreover, the variable Prandtl number is more effective than the constant Prandtl number in enhancing the heat transfer rate.