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2D thermal radiation distribution together with I–V and L–I characteristics has been measured and analyzed in forward and reverse biased p–n heterostructures based on InAs0.9Sb0.1 and grown onto n-InAs substrates. The measurements revealed a sufficient difference in the temperature distribution onto the sample surface at forward and reverse bias, which is explained by an impact of heat pump operation initiated by an electron–phonon interaction at the p–n junction and diode contacts at U < 0. [ABSTRACT FROM AUTHOR]

Along with device miniaturization, severe heat accumulation at unexpected nanoscale hotspots attracts wide attentions and urges efficient thermal management. Heat convection is one of the important heat dissipating paths at nanoscale hotspots but its mechanism is still unclear. Here shows the first experimental investigation of the convective heat transfer coefficient at size-controllable nanoscale hotspots. A specially designed structure of a single-layer graphene supported by gold-nanorod array is proposed, in which the gold nanorods generate hundreds of nanometers heating sources under laser irradiation and the graphene layer works as a temperature probe in Raman thermometry. The determined convective heat transfer coefficient (1928+155 −147 W m−2 K−1 for the 330 nm hotspot and 1793+157 −159 W m−2 K−1 for the 240 nm hotspot) is about three orders of magnitude higher than that of nature convection, when the simultaneous interfacial heat conduction and radiation are carefully evaluated. Heat convection, thus, accounts to more than half of the total energy transferred across the graphene/gold nanorods interface. Both the plasmon induced nanoscale hotspots and ballistic convection of air molecules contribute to the enhanced heat convection. This work reveals the importance of heat convection at nanoscale hotspots to the accurate thermal design of miniaturized electronics and further offers a new way to evaluate the convective heat transfer coefficient at nanoscale hotspots. [ABSTRACT FROM AUTHOR]

Liquid metal phase change materials have the advantages of high thermal conductivity and high volumetric latent heat, which are expected to address the growing challenges of thermal management of advanced electronics. In previous studies, the effect of radiative heat transfer from fins of a phase change heat sink on thermal management performance has rarely been considered. In this study, radiative coating materials with high emissivity were prepared and coated on the fins of the liquid metal phase change heat sink. The effect of radiative heat transfer on the performance of liquid metal phase change heat sink was investigated. The experimental results of continuous heating under natural convection conditions show that the introduction of the radiative coating with an emissivity of 0.9298 can extend the time for the surface temperature of the heat source to reach 100 °C by 9.4%, while shortening the recovery time of the phase change heat sink by 14.9%. The results of high-power cyclic heating indicate that the high emissivity coating can reduce the peak temperature by 16.6 °C in the tenth working cycle. A simplified numerical model was subsequently developed and validated to determine the specific effects of phase change and radiative heat transfer on the overall thermal control performance. The radiation-enhanced liquid metal phase change heat sink proposed in this study is simple and maintenance-free. It is expected to address the thermal management issues of electronic devices that cannot use active cooling or operate in thin-air environments. [ABSTRACT FROM AUTHOR]

Picosecond ultrasonics is a technique where coherent acoustic phonons are generated with frequencies in the GHz frequency range. When optical detection is operated in a transparent medium, the interaction of these phonons with the probe pulses yields oscillations in the time domain that reveal Brillouin scattering. Their frequency is at the Brillouin frequency shift, commensurate with the phonon velocity. As the pump–probe experiments are time-resolved, changes in the Brillouin frequency with time can be attributed to changes in sound velocity with depth. As sound velocity is temperature-dependent in liquids, we show that the picosecond ultrasonics technique can be used for temperature depth profiling in liquids. In this work, the concept is proved using the pump absorption itself as a heat source and confronting measured changes in Brillouin frequency with depth with data resulting from the derivation of a 3D modeling of the temperature rise in the liquid. We demonstrate the remote depth profiling of temperature, with measured data spaced at a distance less than the optical wavelength. [ABSTRACT FROM AUTHOR]

This paper established a three-dimensional transient MHD model of a high-current multi-component vacuum arc under a transverse magnetic field (TMF) to simulate the dynamic characteristics of plasma parameters in the uniform motion mode of a contracted arc under lower TMF. The model considered the ionization–recombination process among the multi-components and used the P1 model to calculate the thermal radiation losses. The simulation results show that the ion number density of The TMF arc is on the order 1024 m−3, and when the plasma temperature reaches 4.3 eV, the effects of thermal radiation cannot be ignored. The majority of the plasma from the cathode and anode undergo acceleration and then deceleration before finally intersecting at the center of the arc, creating an extreme value of the density and the pressure, where a large amount of kinetic energy is converted into internal energy. The arc will be bent and deflected under the action of the ampere force, and the deflection of Cu3+ is especially obvious. The TMF affects the collision strength of the jet in the intersection area and, thus, affects the ion density, in which the change of Cu2+ is dominant. The ionization–recombination process of ions is mainly determined by the electron temperature, which is affected by the arc current. As the current decreases, Cu1+ increases and Cu2+ and Cu3+ decrease, and the change in ionization rate is the main reason for the change in the proportion of each ionic component; the heat flux density to the anode and cathode is on the order of 1010 W/m2, which heats the front of the arc and ensures the stable movement of the arc. Meanwhile, due to the high ion number density, the ion heat flux accounts for the main part of the heat flux, and the anode exhibits a higher proportion of ion heat flux. [ABSTRACT FROM AUTHOR]

The integration of a composite of porous medium with phase change material (PCM) offers significant advantages in thermal management systems, enhancing heat transfer efficiency and addressing various thermal regulation challenges. This approach utilizes the PCM's latent heat absorption and the enhanced thermal conductivity provided by the porous medium, resulting in optimized system performance. Its applicability spans across electronics cooling and building insulation systems. However, predicting the thermal behavior of this composite material is challenging, necessitating computational tools to anticipate its response under different conditions and evaluate its influence on cooling strategies. The objective of this study is to create a computational tool specifically tailored to evaluate constitutive parameters of this composite material, thereby providing a comprehensive description of its thermal behavior. To achieve this goal, the multiscale homogenization principle is employed to assess the composite's effective thermophysical material properties using the representative volume element approach. The repeating unit cell of the aluminum lattice is incorporated into the PCM to define a representative volume element. The finite element method (FEM) is utilized to solve the three-dimensional homogenization problem, yielding an orthotropic effective thermal conductivity due to the inherent symmetry of the repeating material cell. Moreover, the study leverages the apparent heat capacity method to effectively manage the phase transitions within the PCM domain, utilizing smooth and temperature-dependent functions to accurately describe the thermophysical properties of the PCM. Integrating the composite into battery pack thermal management, this study thoroughly examines thermal dynamics by comparing outcomes with and without PCM integration. The transient thermal problem is accurately tackled using the FEM, employing the evaluated effective constitutive parameters of the homogenized composite to minimize computational effort. The results indicate a notable decline in the highest temperatures of the battery pack, leading to a reduction of about 14 °C at the specific moment when the phase change material fully transitions into its liquid form. The obtained results emphasize the effectiveness and practical feasibility of the proposed thermal management strategy. The modeling approach presented provides a robust tool with significant efficiency in reducing computational time for analyzing the thermal behavior of large models, as the utilization of the homogenization technique notably decreases the computational time. [ABSTRACT FROM AUTHOR]

This study investigates the structural effects on the cross-plane thermal conductivity of Li4Ti5O12-based anode active material. Three structures are investigated: a basic structure consisting of LiBr/LiCl/Li4Ti5O12, polyvinylidene difluoride, and Super P (sample #1); a structure without Li4Ti5O12 (sample #2); and a structure without LiBr/LiCl (sample #3). Despite its high porosity level (77%), sample #1 exhibits higher thermal conductivity than sample #3 (64% porosity) in both air and vacuum conditions, potentially due to the extra structural bonding provided by LiBr/LiCl. The observed difference in cross-plane thermal conductivity between air and vacuum conditions provides insights into the configuration of the anode's active material in the heat transfer direction. The lower limit corresponds to the parallel thermal circuit configuration of active material and air, which is the product of the sample's porosity and thermal conductivity of air. Our analysis suggests that in sample #2, the anode's active material and air inside the pores demonstrate a more serial configuration, while in sample #3, they exhibit a more parallel configuration in the heat transfer direction. However, the thermal conductivity difference observed for sample #1 falls below the theoretical lower bound indicating significant thermal radiation within the pores. Furthermore, the in-plane thermal conductivity is predominantly controlled by the copper foil. Sample #2 exhibits the lowest in-plane thermal conductivity. This is attributed to the severe oxidization of the copper foil by LiBr/LiCl, which is confirmed by structure characterization. [ABSTRACT FROM AUTHOR]

High Chern number topological insulators can be obtained in a film of layered magnetic block system theoretically and experimentally. With nonzero Chern numbers, Chern insulators become valuable for fundamental topological physics and for improving next-generation electronic devices. We study energy and angular momentum radiation from layered topological insulators using the Dirac Fermion approach and by Green's function method. We make a connection between radiation magnitude and topological phase transitions. We find that the magnetic exchange field, intra-layer coupling, and inter-layer interaction are efficient measures to modify the energy radiation of layered topological materials. Moreover, the magnetic exchange field is indispensable for emitting angular momentum due to the need for breaking time-reversal symmetry. [ABSTRACT FROM AUTHOR]

Underwater pulsed spark discharge has been widely used in industrial fields as a source of shock waves or acoustic waves, and numerical modeling of the discharge and pressure wave characteristics is necessary to improve the application performance. In this paper, a numerical model is proposed that couples the circuit equation, the mass and energy conservation equations, and a momentum conservation equation based on the Rankine–Hugoniot conditions. A tabulated wide range equation of state and conductivity data of water are used, and various physical processes during the plasma channel expansion are considered, including the energy flow and mass exchange between the channel and the surrounding water due to thermal radiation, evaporation, and condensation. The model self-consistently solves the circuit current and voltage, the plasma channel parameters including composition, temperature, conductivity, pressure, etc., and the pressure profile at a certain distance from the discharge channel. The calculated results show good consistency with the experimental measurements, and three sets of experimental results from other literature are tested to further verify the applicability and effectiveness of the model. [ABSTRACT FROM AUTHOR]

The article is dedicated to the numerical simulations of thin-layer structures based on CdTe semiconductors, which can be fabricated by using low-cost technologies. Structures Mo/Au/CdS/CdTe/Au, and their modifications, with different thicknesses of the main layers are investigated. The possibility of creating a detector of ionizing radiation based on these structures, which has selective properties with respect to the radiation type, and very low operation voltage, is shown. The detection efficiencies of α -, β -, and γ -radiation in different energy ranges were calculated based on the obtained values of energy losses of ionizing particles, which are proportional to the output signal of the detector. The use of such detectors, together with a solid-state converter made of boron carbide containing either natural boron nat B or boron enriched with the 10 B isotope up to 95 % , for the detection of thermal neutrons was also studied. It was shown that the structures could be used to create α -particle spectrometers, given that the CdTe thickness is tailored to the highest expected α -particle energy. Detectors with thin CdTe (1–5 μ m) can be successfully used in the counting mode. For neutron detection, stacking multiple single structures into sandwich structures was proposed and investigated. In such a configuration, the detector qualities were markedly improved: the efficiency of neutron detection reached ∼ 60 % , while the sensitivity to the background γ - and β -radiation was ∼ 100 times lower than that for neutrons. The very low sensitivity of the simulated neutron detectors to the neutron incidence angle was shown. [ABSTRACT FROM AUTHOR]

The effect of longitudinal ventilation on hydrogen jet fires was investigated in tunnel. The extended flame length, temperature, and thermal radiation flux were measured for nozzle diameters (1∼5.12 mm), tilt angles (30–60°) and pressures (1–4 MPa). The results indicate that the longitudinal wind speed has a suppressive effect on the extended flame length on the ground. The extended flame length on the ground decreases with increasing wind speed. Longitudinal ventilation also has a suppressive effect on the gas temperature around the flame, and the maximum temperature difference decreases with increasing wind speed. Based on the geometric model of the extended flame, a fitted relationship between the dimensionless extended flame length and the longitudinal wind speed was established. Additionally, a fitted relationship between the dimensionless peak flame temperature and the normalized position was also proposed. • Longitudinal ventilation hydrogen jet fire experiments were conducted in a model tunnel. • Longitudinal ventilation effects on flame behavior, temperature and radiation were focused. • The formulas of dimensionless flame length and temperature were proposed. • The maximum temperature difference decreases with increasing wind speed. [ABSTRACT FROM AUTHOR]

A brief and scalable scraping method for fabricating the passive radiation cooling thermal emission film as a mobile phone screen protector. [Display omitted] • Straight forward and scalable scraper method for a passive daytime radiation cooling film. • Highly transparent self-adhesive mobile phone protective screen film with cooling performance. • Non-selective plant polysaccharide-based thermal emission film with high emissivity and elasticity. Passive daytime radiative cooling (PDRC) is a promising approach to address energy, environmental, and safety issues caused by global warming, with high emissivity in a transparent atmospheric window and high reflectivity in the solar spectrum. However, most demonstrations of PDRC rely mainly on complex and expensive spectral selective nanophotonic structures, requiring specialized photonic structures that are both expensive and difficult to obtain. The superiorities of low-cost, abundant resources, renewability, and high value-added biomass resources prompt Gleditsia sinensis polysaccharides (GSP) to be used in thermal emission materials to explore further the characteristics of regulating object temperature within a specific range without any external energy consumption. The three-layer thermal emission film (PDMS 3 PG 3/t4) obtained by the scalable scraping method has high transparency, hydrophobicity (114.2°), and super flexibility. The spectral variations of non-selective PDMS 3 PG 3/t4 (1.0 wt% GSP, 800 μm thickness) in the 3–5 μm and 8–13 μm waveband ranges were discussed in detail, and high emissivities of 69.1 % and 92.2 % were obtained, respectively. PDMS 3 PG 3/t4 was appointed a mobile phone screen film and experimented with a 4.9 °C average temperature difference below ambient temperature, materializing prime PDRC and desiring to broaden the passive cooling technology and reduce the global energy burden. [ABSTRACT FROM AUTHOR]

By applying torque, turning effects are produced on the flow of the fluids flowing between the two concentric cylinders, which have different radii and are moving in the same or opposite directions with similar or variable velocities. This kind of flow is called torsional flow. In this article, different cases are taken into account to study the variation in heat transfer for the flow of nanofluid between the two concentric cylinders. The influence of magnetic fields and nonlinear thermal radiation is also examined. After non-dimensionalizing the formulated equations, the bvp4c (boundary value problem of $$\textstyle4^{th}$$ 4 th order) MATLAB function is utilized to determine the impact of different parameters on flow rate and fluid temperature. The graphical interpretation helps to show the behavior of emerging parameters. [ABSTRACT FROM AUTHOR]

In this study, the Darcy or non-Darcy stagnation point flow and thermal analysis of ternary composite nanofluids with modest Prandtl numbers across stretched surfaces that are susceptible to slip or no-slip environments are examined. The concept of non-linear thermal radiation is brought into play. It has been decided to apply non-linear slip. Homogeneous and heterogeneous chemical reactions, or HHCRs, make the flow problem harder to solve. Along with the shooting method, the Runge–Kutta method of the fourth order is an important part of the numerical solution needed for the non-dimensional and non-linear system of partial differential equations. In slip and no slide, both the amplified porosity parameter and the Forchheimer number work to slow down the speed of the fluid. In a medium that may be Darcy or non-Darcy, an increase in the slip parameter causes the fluid velocity and temperature to sputter and stop. When Darcy and non-Darcy media and slip and no-slip conditions are taken into account, surface viscous drag goes down as the strength of the porous matrix goes up, heat transfer rate goes down as the Brinkman number goes up, and mass transfer rate goes up as the homogeneous reaction rate parameter goes up. [ABSTRACT FROM AUTHOR]

This study investigates the Walters' B fluid in two-dimensional boundary layer flow through a porous medium of an exponentially stretching sheet. In the face of Newtonian heating, the Cattaneo-Christov heat flux model which expresses the thermal relaxation time is examined together with heat generation/absorption for the heat equation. The resulting equations of the model are resolved into non-dimensional forms, which are further performed by the Homotopy Analysis Method. The key findings along with the result obtained demonstrated that the Cattaneo-Christov heat flux which depicts the thermal relaxation time makes low the temperature field, indicating that the neighbouring particles crave for more time for the heat to fall deeper, while heat generation/absorption, as well as Newtonian heating, permit the quick infiltration of thermal sequel to the quiescent fluid which in turn aids the dryness of the materials. Meanwhile, the variation in local Weissenberg number triggers viscoelasticity whose application is crucial for the processing of the polymer in industries and other related disciplines. [ABSTRACT FROM AUTHOR]

Indian onion producers experience significant economic losses as a result of the unpredictable fluctuations in onion prices during the harvesting and postharvest stages. To address these difficulties and increase farmers' earnings, the transformation of onions into value-added goods such as onion paste, onion powder, onion sauce, and onion oil has emerged as a possible option. The objective of this project is to create a smart solar drying system based on Internet of Things (IoT) technique specifically designed for the dehydration of recently harvested red onions. In April 2023, a series of five experimental tests were carried out, examining the effects of different onion slice thicknesses ranging from 2 mm to 4 mm, with intervals of 0.5 mm. Each trial consisted of running the dryer for a duration of 9 h, specifically from 9:00 a.m. to 6:00 p.m., throughout the daylight hours for three consecutive days. The experiment involved evaluating different drying characteristics, such as moisture content on dry and wet bases, shrinkage ratio, and thermal efficiency. The drying time required to achieve a 10% moisture level (w.b.) was reduced by 30.19%, 16.98%, 11.32%, and 3.77% when comparing a 4-mm slice thickness to thinner alternatives of 2 mm, 2.5 mm, 3 mm, and 3.5 mm, respectively. The dryer had a superior thermal efficiency of 27.89% when the thickness was 2 mm, in contrast to 19.50% when the thickness was 4 mm. Significantly, onions that were dehydrated from slices measuring 2 mm and 2.5 mm in thickness showed exceptional suitability for the production of powdered onion. [ABSTRACT FROM AUTHOR]

A system combining the ventilated concrete floor (VCF) with solar air collector (SAC) in buildings has been applied in the western Sichuan Plateau for nighttime heating. However, the dynamic model coupled with uneven solar radiation of SAC-VCF is absent, thus the thermal behavior of the system is difficult to predict in practice. In this research, a coupled model is built to predict the thermal characteristics of the room with the SAC-VCF system under uneven solar radiation. The calculation model of VCF considers the uneven distribution of solar radiation on the floor surface, established by combining the resistance-capacitance (RC) network model and the number of transfer unit (NTU) model using the discrete method and validated by experimental data. A 3R2C model is utilized to model envelopes, validated by simulation results. The calculation error of surface temperature and room air temperature is within 5%. Then a case study is conducted with the validated model to predict the thermal performance of the SAC-VCF system with even and uneven solar radiation. Results indicate that under uneven solar radiation, the local surface temperature significantly increases to 35.1 °C, 9.1 °C higher than even solar radiation. Meanwhile, under uneven solar radiation, the heat transfer of supply air and surface of VCF is increased by 14% and 6%, respectively. Besides, the room air temperature is almost equal of two cases, while the operative temperature is 0.4 °C lower under uneven solar radiation. The model is beneficial to further study the influencing factors of this system. [ABSTRACT FROM AUTHOR]

The back plate is an important component of the ion source because of its multiple roles including heat load removal during beam operation. The main components of the back plate are (1) a Type 304L stainless steel (SS304L) magnet positioning plate that holds samarium cobalt permanent magnets required for the confinement of ion source plasma, (2) an oxygen-free electronic copper cooling plate with 35 inner and 8 outer cooling channel grooves (each of which is 4 × 1.8 mm2) that is vacuum brazed with a SS304L magnet positioning plate, and (3) a SS304L magnet cover plate. In this paper, the back plate is successfully fabricated, and a high heat flux experiment is done at the High Heat Flux Test Facility Center with an electron beam power of 200 kW for 458 s. The uniform incident heat flux is 2.5 MW/m2. Demineralized water at 34°C is supplied at the rate of 1 kg/s to the cooling plate at inlet pressure of 8.2 bars to remove the high heat load. The surface temperature of the copper plate is measured by an infrared camera, and three temperature regions are observed. The measured average surface temperature of the cooling plate is ~152°C. The bulk water temperature rise ΔTw is ~39.42°C. The estimated absorbed heat flux is ~2.04 MW/m2, and the heat absorption coefficient is 81.6%. The measured leak rate after the heat flux test is 1.6 × 10−8 mbars∙L/s. These High Heat Flux Test experimental results will be useful to study the thermomechanical performance of the back plate and to understand the effect of increasing the beam pulse length. [ABSTRACT FROM AUTHOR]

This paper comprehensively analyzes the consequences of thermal radiation on natural convection, electrical and thermally conducted water-based flowing nanofluid past an exponentially accelerating surface. The paper investigates the thermal and momentum boundary layers with the effects of radiation and heat generation on the nanofluid flow. The magnetic field acts perpendicular to the flow direction. The non-dimensional governing equations were numerically solved using the Finite Difference Method (FDM) and illustrated through the use of MATLAB software. Thermal radiation enhances the nanofluid temperature and velocity, an essential phenomenon for designing solar collectors. The heat generation factor reduces the skin friction of the flow. It improves heat transfer by convection rather than conduction mode, enhancing the velocity and dropping the temperature of the nanofluid. The influence of some dimensionless parameters on the nanofluid velocity and temperature led to this paper's conclusion. Mass and heat transmission are fundamental due to their daily applications, including human body temperature regulations, electronic devices, and heating/cooling systems. [ABSTRACT FROM AUTHOR]

In this paper, we introduce an entirely new solar absorber design—a multi-layer periodic stacked structure. Through coupling effects, this design has perfect ultra-wideband absorption characteristics. The absorber structure is composed of four absorption units with varying cycle lengths, which are cyclically stacked on the surface of the refractory metal Cr. Each cycle encompasses three-layer nanosheets of Ti–SiO2–GaAs. We verify through finite difference time domain method (FDTD) simulations that the absorber achieves an absorption efficiency of 97.8% within the wavelength range of 280 nm to 3000 nm, with an average efficiency of 96.6% under the AM1.5 standard solar spectrum. The absorber can achieve such a remarkable absorption effect because of surface plasmon resonance (SPR) and Fabry–Pérot resonance effects. At 1500 K, this structure exhibits a thermal radiation efficiency of up to 97.83%. Furthermore, the design is not affected by polarization and it is less affected by the incident angle of the light source. These absorption spectra remain consistent regardless of whether it is in the TE or TM mode. Even when the angle of incidence is increased to 60 degrees, the absorption efficiency remains high. Its unique structure and excellent performance characteristics provide higher solar energy efficiency. These outstanding features enable solar absorbers to have broad application potential in improving solar energy efficiency. [ABSTRACT FROM AUTHOR]

This investigation uses the Tiwari and Das nanofluid model to enhance the heat transfer rate in Sutterby nanofluid over a Riga plate. The effects of heat source/sink, viscosity dispersion, and mass flow for water-based fluids are also considered in this work. Sutterby fluid has been utilized to investigate the rheological features of nanofluids. The transverse Lorentz force produced by the Riga plate assists in the flow down the plate by producing an electromagnetic field. The main aim of this investigation is to evaluate the presence of two different types of nanoparticles in water, specifically silicon carbide (SiC) and copper (Cu). Dimensionless variables are first used to convert the mathematical model into a non-dimensional form. The similarity approach is then used to further rewrite the non-dimensional partial differential equations into a set of similarity equations. The bvp4c function in MATLAB software provides a numerical solution to these equations. The effects on temperature and velocity profiles of many physical factors, including the Reynold number, heat source/sink, and Deborah number, have been analyzed and presented. Furthermore, using tables, a detailed analysis of the skin friction coefficient and local Nusselt numbers is conducted. The results show that convective flow is suppressed when solid nanoparticles are added to the base fluid. The velocity distribution improves as Deborah and Reynold's numbers get a higher value. Also, the temperature field improves by incrementing exponential and thermal heat source/sink parameters. [ABSTRACT FROM AUTHOR]

This study investigates the impact of electroosmosis on the peristaltic flow of unsteady micropolar nanofluid with heat transfer. The findings could enhance the design of peristaltic pumps, potentially improving drug delivery systems, simulations of blood flow in medical devices, and cancer treatments. The fluid under investigation adheres to a micropolar model and flows through a microchannel that exhibits peristalsis along its walls. Moreover, the system is subjected to various external effects, including a uniform magnetic field, the electroosmotic phenomenon, heat absorption, and a chemical reaction with activation energy. Consequently, the problem is mathematically modulated by a system of nonlinear partial differential equations governing the velocity, temperature, and nanoparticle concentration. By employing wave transformation, these governing equations are reduced to ordinary differential equations (ODEs). The reduced equations were solved both analytically, using the homotopy perturbation method, and numerically, using the Runge–Kutta–Merson method. A comparison was made between the solutions, which were found to be closely aligned. Furthermore, a series of figures were employed to provide visual representation and discussion of the implications of the physical properties. The calculations reveal that the electroosmotic flow (EOF) enhances the axial flow of the micropolar fluid along the direction of the applied electric field. It is also observed that the increase in the activation energy (which indicates a low reaction rate) increases the concentration profile whereas the increase in the reaction rate parameter reduces the concentration profile. Additionally, the spin velocity of the particles is diminished by either an increase in the magnetic parameter or the coupling parameter. [ABSTRACT FROM AUTHOR]

This study investigates the electroosmotic flow and thermal transport of nanofluids, specifically aluminum oxide and titanium dioxide, within tapered arteries with stenosis. Using the finite difference method (FDM), we modeled the flow dynamics and heat transfer mechanisms under the assumption of low Reynolds numbers and mild stenosis. The study focuses on the effects of nanoparticle volume fraction, heat absorption parameters, and electroosmotic forces on blood flow, velocity profiles, and temperature distribution. Results show that increasing nanoparticle concentration and heat absorption significantly reduce flow velocity, particularly in divergent artery geometries. Additionally, the inclusion of electroosmotic effects enhances heat transfer, while the Grashof number influences central velocity. These findings offer valuable insights into optimizing nanoparticle-based therapeutic interventions for cardiovascular treatments, providing a framework for enhancing drug delivery systems and improving the efficacy of heat-based therapies. The study’s outcomes could lead to improved diagnostic tools and therapeutic strategies for managing cardiovascular diseases. [ABSTRACT FROM AUTHOR]

The medical industry extensively uses nanoparticles for applications such as wound dressing, artificial organ components, drug delivery, tissue engineering, and cardiovascular disease treatment. The incorporation of nanoparticles into the base fluid enhances the rate of heat transmission and additionally decreases blood pressure. This study aims to examine the effects of a new tetra-hybrid nanofluid model, which includes nanoparticles, on the flow of blood through a stenosed artery with a circular shape. Model partial differential equations (PDEs) incorporate phenomena such as thermal radiation and viscous dissipation. Furthermore, we transform these modeled PDEs into dimensionless ordinary differential equations (ODEs) using self-similarity variables and numerically solve the proposed ODEs using the well-established Lobatto IIIa numerical technique. The impact of several dimensionless parameters on the heat transfer rate, skin friction, velocity, and temperature fields has been computed and analyzed using figures and tables. Moreover, we conducted a computational fluid dynamics (CFD) investigation on a tetra-hybrid nanofluid, using blood as the base fluid. The results indicate that heat transmission is higher in tetra-hybrid nanoparticles compared to tri-hybrid and di-hybrid nanofluids. The volume fraction of nanoparticles in the base fluid increases, resulting in a decrease in the surface drag coefficient and a decrease in the heat transport phenomenon. Amplification in the thermal radiation parameter improves heat transfer, helping to remove toxins and plaque from blood flowing through arteries. An increase in thermal radiation generates excess heat that dilates inflexible arteries, facilitating blood flow. From CFD analysis, it is observed that thermal conduction k and heat transfer coefficient h amplify by improving Reynolds number. Pressure at the outlet interface of the tube decreases from 3058 Pa to 2996 Pa for the case of a 10% volume fraction of nanoparticles. Velocity boundary layer thickness decreases from 1.46 to 1.37 with an increase in the volume fraction of nanoparticles from 1% to 10%. Heat deliverance rate amplifies in the case of tetrahybrid nanofluid 2.5394–2.6147 in contrast to trihybrid nanofluid 2.4008 to 2.4711 by amplifying Rd from 0.7 to 1.1. The surface drag coefficient amplifies by magnifying Re but the Nusselt number diminishes by improving the volume fraction of nanoparticles. [ABSTRACT FROM AUTHOR]

AbstractThe phenomenon of peristalsis has gathered significant attention from researchers due to its wide-ranging applications in fields such as biological sciences, industries, and biomechanics. Its practical relevance can be observed in various processes, including blending food in the digestive tract, flow in small blood vessels and the movement of cilia. Inspired by such useful applications, this theoretical study applies an analytical model that examines the movement of magnetically induced Sisko nanofluid in an asymmetric channel considering the factors like viscous dissipation, multiple slip, thermal radiation, and double diffusive convection. The fluid flow was administered using partial differential equations (PDE’s), transformed into a set of interconnected ordinary differential equations. These non-linear equations were further numerically solved by the NDSolve function in Mathematica. According to our outcomes, the temperature profile increases as the thermal slip factor rises. Moreover, the concentration and nanoparticle profile decrease with increasing values of the concentration slip and nanoparticle slip parameters. It can also determine that when the impact of thermal radiation increases, the temperature profile drops. Such a model has practical applications in simulating the small vessel transportation of particle in hemodynamics as well as in the field of biomedical and medical engineering for nanofluid peristaltic pumps. [ABSTRACT FROM AUTHOR]

The Cattaneo-Christov double diffusion theory extends the classical Fourier and Fick laws by introducing a relaxation time, accounting for thermal and mass diffusion at finite speeds rather than assuming instantaneous diffusion. This theory works especially well for explaining how non-linear mixed convection and chemical reactions over a stretching surface behave and boost heat and mass transfer of Sutterby nanofluid. Using the proper similarity transformations, the governing model is converted into a non-dimensional form. It is then numerically solved using the Runge-Kutta-Fehlberg (RK-45) method in conjunction with shooting procedures. The impact of the heat transport rate on the significant variables (Brownian motion, Biot number and thermal relaxation time parameter) is addressed vis sensitivity studied using response surface methodology (RSM). It is concluded that Forchheimer number and Deborah number on velocity profile is quite similar. The influence of temperature difference parameter on the thermal distribution and mass transport rate is reverse. The opposite behavior of nanoparticle concentration and mass transport rate is viewed for thermophoretic parameter. Furthermore, the heat transport rate is more sensitive to the impact of Brownian motion comparing with Biot number and thermal relaxation time parameter. • Simulating the heat transfer enhancement for non-Darcian Sutterby nanofluid flow. • This study views the behavior of heat and mass transport toward a stretchy surface. • Cattaneo-Christov double diffusion theory discussed in θ (η) and ϕ (η) equation. • The Roseland approximation is adopted for Brownian and thermophoretic diffusion. • Optimization approach employed via (RSM) for the important parameters. [ABSTRACT FROM AUTHOR]

This paper studies the similarity of silver-blood-based Carreau–Maxwell, Carreau–Oldroyd-B and Carreau–Jeffrey binary nanofluids on the parabolic trough solar collector. By the energy equations, Joule heating effects and nonlinear thermal radiation were integrated. The velocity slip condition by the solid–liquid interface was again worked out. In this model, magnetic field aspects and viscous dissipation were again taken into account. The converted construction was modeled into ordinary differential methods with the help of appropriate comparison applications. This governing relation on current flow problem was given graphically and determined mathematically by applying made-up MATLAB computational tool with the aid of renowned mathematical shooting methods bvp4c (Lobatto's IIIa Formulae). This mathematical outcomes are given in tabular and graphical models. It was observed that the nonlinear thermal radiation aggregates the temperature profile. This skin friction was improved for greater values of magnetic parameter by 6.16%. Moreover, the local Nusselt number was reduced about developing values of radiation parameter into 71.78%. Moreover, these Casson–Jeffrey and Casson–Maxwell nanofluid models are more efficient than the Casson–Oldroyd-B nanofluid models. [ABSTRACT FROM AUTHOR]

Activation energy and thermal radiation as a means of heat transfer are significant and fascinating phenomena for scientists and researchers because of their significance in cancer treatment. As a result, heat kills cancer cells and shrinks tumors, making hyperthermia therapy a cutting-edge cancer treatment. This paper examines the peristaltic motion of a Johnson–Segalman nanofluid across an asymmetric pliable microchannel under the impact of activation energy. We obtained the governing equations for the non-Newtonian nanofluid. Partial differential equations (PDEs) are reduced to ordinary differential equations (ODEs) under the assumption of large wavelengths and tiny Reynolds number assumptions. The flow patterns and trapping phenomena were numerically generated using the NDSolve command of the computational mathematical software Mathematica. The influence of important liquid parameters was examined with graphical representations of the results. The current study reveals an enhancement in the heat generation parameter, an enhancement in the temperature and a reduction in the concentration. [ABSTRACT FROM AUTHOR]

Cancer is one of the universal popular healthcare problems, and there is a struggle to find advanced fresh medicines andidentify superior ways of distributing medications. Cancer is harmful and deadly to maximum of its patients. Cytotoxic agents are carried by cancer cells, to increase efficacy and protection. This reminds us that nanotechnology can be utilized for medicine. This current allegation has built into gold nanomaterials which could conquer and heal — it being the material considered like gold (atomic number 79). It gives a large amount of heat and contributes to the therapy of malignant tumors. Therefore, it is urgent to investigate the flow of blood-based gold nanoparticles over the porous medium for injection/suction effects. Time-dependent viscosity was used in Reynolds exponential model. The existence of magnetic field and nonlinear thermal radiation was integrated into the system. Ensuing equations were interpreted by its nondimensional model by applying comparison renovation. This Lobatto IIIA formula (known as bvp4c) was working to acquire multiple solutions. This findings indicate that temperature increases due to magnetic and radiation effects. Temperature and velocity profiles by injection are greater although related to the suction phenomenon. Further, the temperature and velocity augment by the inclusion of gold nanoparticles into blood flow. [ABSTRACT FROM AUTHOR]

[Display omitted] • A biomimetic hollow structural C@CuO nanofibrous membrane was developed. • The hollow structure localized thermal energy in the membrane to suppress heat loss. • The C@CuO membrane exhibited a high and stable evaporation rate for saline/dye water. • The mechanisms of heat localization and high evaporation were proposed. The rational design of material structures can be an effective approach to enhance the performance of solar-driven clean water production. In this study, a hollow structural nanofibrous membrane was developed by mimicking the hollow structure of polar bear hair using coaxial electrospinning. The shell layer consisted of carbon nanoparticles (C NPs) decorated CuO nanosheets (C@CuO), that exhibited photothermal conversion capacity. Meanwhile, the core layer containing hydrophilic polyvinylpyrrolidone (PVP) was eliminated to generate the hollow structure. The C NPs enhanced the membrane's light absorption to increase thermal energy harvesting, while the CuO nanosheets improved the membrane's wettability enhancing the water supply. Furthermore, the hollow structure limited air convection, prevented heat conduction, and minimized heat radiation, enabling heat localization to be achieved inside the membrane to suppress heat loss during evaporation. For 3.5 wt% saline water and actual dye wastewater, the C@CuO nanofibrous membrane achieved high evaporation rates of 1.36 kg·m−2·h−1 and 1.31 kg·m−2·h−1, respectively, under 1 sun illumination. Moreover, even after continuous 6-h evaporation tests, the evaporation rate of the C@CuO membrane remained virtually unchanged, highlighting its long-term stability with regard to salt resistance in real-world applications. Additionally, the remarkable flexibility of the C@CuO membrane offers convenience during operation and guarantees dimensional stability when it is subjected to external stresses. These discoveries should inspire subsequent research on developing delicate architectural materials and exploring their potential applications in various fields, including energy generation, clean water production, and thermal insulation. [ABSTRACT FROM AUTHOR]

The aim of this study is to estimate the solution of Eyring–Powell nanofluid model (EPNFM) with Darcy Forchheimer slip flow involving bioconvection and nonlinear thermal radiation by employing stupendous knacks of neural networks-based Bayesian computational intelligence (NNBCI). A dataset for the designed NNBCI is generated with Adam numerical procedure for sundry variations of EPNFM by use of several variants including slip constant, Schmidt number, mixed convection parameter, Prandtl number, and bioconvection Lewis parameter. Numerical computations of various physical parameters of interest on EPNFM are estimated with artificial intelligence-based NNBCI and compared with reference data values generated with Adam's numerical procedure. The accuracy, efficacy, and convergence of the proposed NNBCI to successfully solve the EPNFM are endorsed through M.S.E, statistical instance distribution studies of error-histograms, and assessment of regression metric. The proposed dataset exhibits a close alignment with the reference dataset based on error analysis from level E − 1 1 to E − 0 5 authenticates the precision of the designed procedure NNBCI for solving EPNFMs. The executive and novel physical importance of parameters governing the flow, such as nanofluid velocity, temperature, and concentration profiles, are discussed. The observations imply that the presence of the slip constant, mixed convection parameter and Lewis number influences the velocity of the nanofluid. However, it is observed that temperature of the nanofluid declines for higher values of Prandl number while the concentration of nanofluid improves with increasing values of Schmidt number. [ABSTRACT FROM AUTHOR]

In this study, we present a novel approach that utilizes the Levenberg–Marquardt algorithm (LMA) based on artificial neural networks (ANNs) to evaluate the flow characteristics of a thermally evolved blood-based nanofluid in the presence of peristalsis and electroosmosis. The Casson fluid model is employed to govern the non-Newtonian characteristics observed in the flow of blood. In addition, the thermal properties of the nanofluidic medium in contact with platelet magnetite nanomaterials are also studied in detail. Further, the effects of thermal radiation, thermal buoyancy force, magnetic field and Joule heating are also given due consideration. The mathematically formulated two-dimensional equations describing the flow of Casson liquid are brought into their dimensionless form under the lubrication theory. A dataset for the proposed ANN models is generated to explore various scenarios of the fluidic model by varying the pertinent parameters using NDSolve in Mathematica. The computational approach utilizing LMA is deployed across three distinct phases of performance assessment, distributing the data into training, testing and validation sets at the proportions of 80%, 10% and 10%, respectively. This implementation involves the utilization of 10 hidden neurons. The utilization of regression analysis for testing, mean-squared error calculation, error histograms and correlation assessment in numerical replications of the ANNs is also examined to verify their capability, accuracy, validity and effectiveness. This study is crucial for understanding the peristaltic blood transportation in small blood vessels of living organisms. [ABSTRACT FROM AUTHOR]

The study of molybdenum disulfide, along with iron oxide, has various promising applications due to its thermal, electrical, and magnetic properties. In particular, for the efficient cooling in power devices, enhanced fluid transport in medical devices, chemical processing, and cancer therapy. The utility of both nanoparticles is vital. Hence, with this motivation, this study aims to investigate the characteristics of dissipative heat influenced by the inclusion of viscous and Joule dissipation in the flow of a hybrid nanofluid comprised of molybdenum disulfide (MoS2) and iron oxide (Fe3O4) in the base liquid, ethylene glycol (C2H6O2), within a coaxial permeable disk. The proposed model, encompassing various thermal properties, is transformed into a non-dimensional form by applying appropriate similarity rules. Traditional numerical techniques, such as the shooting-based fourth-order Runge–Kutta method, is employed to obtain solutions. Several profiles are computed for various values of contributing factors within their appropriate ranges employing the numerical scheme implemented in MATLAB. A comparative analysis with previous studies is presented, demonstrating a strong correlation in a specific case and thereby validating the current results. [ABSTRACT FROM AUTHOR]

Steam methane reforming (SMR) consumes a tremendous amount of energy, typically provided by the combustion of natural gas, which leads to carbon emissions. Previous studies have explored methods to replace fossil fuel combustion with SMR, but most these studies have not considered the temperature of the heat transferred. In this study, we attempted to fill this gap in the thermal analysis of external heat-fired SMR. Specifically, the use of waste heat from gas turbines (SMR-GT) and chemical looping combustion (SMR-CLC) was analyzed considering heat transfer modes and temperature ranges using a multizone model. Our results show that the SMR-GT reduces exergy destruction by 37.8% owing to a lower radiative heat transfer rate. SMR-CLC reduces CO 2 emissions by 99.9%, making it the most eco-friendly option. Increasing the temperature improved exergy efficiency by 7% in the GT and 17% in the CLC for SMR. [Display omitted] • External heat-fired SMR is evaluated using a multi-zone model. • SMR-GT reduces exergy destruction by 37.8% due to lower radiant heat transfer rate. • SMR-CLC reduces CO₂ emissions by 99.9%, making it the most eco-friendly option. • Increasing temperature improves exergy efficiency by 7% in GT and 17% in CLC for SMR. [ABSTRACT FROM AUTHOR]

This research work employs a machine learning approach with Python to analyze the complex relation of thermophoretic deposition and radiation effect on the mass and heat transfer of ternary hybrid nanofluid flow over the wedge. The colloidal comprising CoFe2O4, Fe3O4 and ZnO with Engine Oil and Water in equal proportion as a base fluid, is considered here, due to the potential enhancer of thermal performance in numerous applications. The governing PDEs for flow rate, heat and mass transfer are transformed into a system of ODEs and numerical dataset generated by Python for stochastic evaluation through Matlab Neural Network assisted by Levenberg Marquardt Machine Learning Algorithm to extract intricate patterns and comparison between numerical and stochastic simulations. The impact of influencing parameters such as volume fraction, wedge angles, Eckert ratio and Radiation coefficients are analyzed. The outcomes of this research shed light on the synergetic effects of thermophoretic deposition and radiation on the thermal mass exchange of tri-nanohybrid fluid across the sharp edge of the device. This machine learning artificial intelligence (AI) tool is cost-effective and far better than deterministic numerical outputs as compared with analytical evaluations. A detailed graphical representation is embedded in this paper for comparisons and error analysis. Influencing parameters are analyzed for temperature, velocity and concentration profiles. Moreover, engineering parameters are also evaluated and plotted against the infecting agents. Graphical analysis of Nusselt, Sherwood and Skin friction coefficients added for broad spectrum comparison and comprehensive analysis for the significant implementation of the present discussion at the industrial level, for the benefit of production units, heavy industry and energy management systems in numerous fields. [ABSTRACT FROM AUTHOR]

In maximally Ca2+-activated demembranated fibres from the mammalian skeletal muscle, the depression of the force by lowering the temperature below the physiological level (~35 °C) is explained by the reduction of force in the myosin motor. Instead, cooling is reported to not affect the force per motor in Ca2+-activated cardiac trabeculae from the rat ventricle. Here, the mechanism of the cardiac performance depression by cooling is reinvestigated with fast sarcomere-level mechanics. We determine the changes in the half-sarcomere compliance of maximally Ca2+-activated demembranated rat trabeculae in the range of temperatures of 10–30 °C and analyse the data in terms of a simplified mechanical model of the half-sarcomere to extract the contribution of myofilaments and myosin motors. We find that the changes in the ensemble force are due to changes in the force per motor, while the fraction of actin-attached motors remains constant independent of temperature. The results demonstrate that in the cardiac myosin, as in the skeletal muscle myosin, the force-generating transition is endothermic. The underlying large heat absorption indicates the interaction of extended hydrophobic surfaces within the myosin motor, like those suggested by the crystallographic model of the working stroke. [ABSTRACT FROM AUTHOR]

In addition to convective heat transfer, radiation heat transfer constitutes a significant component of the thermal performance of Passive Containment Air-Cooling System (PAS). The installation of radiation plates within the PAS flow channel enhances the convective heat transfer area between the wall and the air, an effect that should not be overlooked. ANSYS Fluent was employed to investigate how the placement and quantity of radiation plates influence the heat transfer efficiency of PAS. The computational results indicate that radiation plates can substantially enhance the thermal performance of PAS. Specifically, when a radiation plate is positioned 0.9 m from the inner wall of the concrete shell, an improvement in PAS heat transfer power by as much as 34.4% can be achieved. However, it was observed that increasing the number of radiation plates has a minimal impact on overall performance; thus, utilizing multiple plates does not further augment the PAS heat transfer capability. Nonetheless, incorporating several radiation plates may contribute to lowering the temperature of the concrete shell. Based on this research, it can be concluded that strategically arranging radiation plates significantly improves the PAS heat transfer capacity. While multiple radiation plates do not provide additional enhancements to heat transfer efficiency under normal conditions, they remain a viable option for mitigating concrete shell temperatures during accident scenarios. [ABSTRACT FROM AUTHOR]

During the heat treatment of round steel bars, a heated charge in the form of a cylindrically formed bundle is placed in a furnace. This type of charge is a porous granular medium in which a complex heat flow occurs during heating. The following heat transfer mechanisms occur simultaneously in this medium: conduction in bars, conduction within the gas, thermal radiation between the surfaces of the bars, and contact conduction across the joints between the adjacent bars. This complex heat transfer can be quantified in terms of effective thermal conductivity. This article presents the original model of the effective thermal conductivity of a bundle of round steel bars. This model is based on the thermo-electric analogy. Each heat transfer mechanism is assigned an appropriate thermal resistance. As a result of the calculations, the impact of the following parameters on the intensity of heat transfer in the bundle was examined: temperature, the thermal conductivity of the bars, the thermal conductivity of the gas, diameter, and emissivity of the bar, and bundle porosity. Calculations were performed for a temperature range of 25–800 °C, covering a wide spectrum of variables, including bar diameters, bundle porosity, and type of gas. The knowledge obtained thanks to the calculations performed will facilitate the optimization of heat treatment processes for the considered charge. The greatest scientific value of the presented research is the demonstration that, thanks to the developed computational model, it is possible to analyze a very complex heat transfer phenomenon using relatively simple mathematical relationships. [ABSTRACT FROM AUTHOR]

Thermal infrared (TIR) images capture temperature in a non-invasive manner, making them valuable for generating 3D models that reflect the spatial distribution of thermal properties within a scene. Current TIR image-based 3D reconstruction methods primarily focus on static conditions, which only capture the spatial distribution of thermal radiation but lack the ability to represent its temporal dynamics. The absence of dedicated datasets and effective methods for dynamic 3D representation are two key challenges that hinder progress in this field. To address these challenges, we propose a novel dynamic thermal 3D reconstruction method, named ThermalGS, based on 3D Gaussian Splatting (3DGS). ThermalGS employs a data-driven approach to directly learn both scene structure and dynamic thermal representation, using RGB and TIR images as input. The position, orientation, and scale of Gaussian primitives are guided by the RGB mesh. We introduce feature encoding and embedding networks to integrate semantic and temporal information into the Gaussian primitives, allowing them to capture dynamic thermal radiation characteristics. Moreover, we construct the Thermal Scene Day-and-Night (TSDN) dataset, which includes multi-view, high-resolution aerial RGB reference images and TIR images captured at five different times throughout the day and night, providing a benchmark for dynamic thermal 3D reconstruction tasks. Experimental results demonstrate that the proposed method achieves state-of-the-art performance on the TSDN dataset, with an average absolute temperature error of 1 °C and the ability to predict surface temperature variations over time. [ABSTRACT FROM AUTHOR]

To improve maneuverability, the focus of photoelectric theodolites is on reducing the weight of the primary mirror and enhancing its optical performance. This study uses MOAT and Sobol methods to identify key parameters that affect design. Using the high-sensitivity part as the optimization domain, six optimization results were obtained based on the multi-objective SIMP topology optimization method and synthesized into a compromise optimization structure. The performance of the mirror before and after optimization was compared on the opto-mechanical–thermal level. Modal analysis shows the optimized structure has a first natural frequency of 716.84 Hz, indicating excellent stiffness and avoiding low-frequency resonance, with a 30.37% weight reduction. Optical performance is also improved, with a 6 μm reduction in the spot diagram radius and an 8.95 nm decrease in RMS. Simulations under real-world conditions show that the lightweight mirror performs better in resisting gravity deformation and maintaining imaging quality. At maximum thermal deformation, the spot diagram radius of the optimized mirror is 1521.819 μm, with only a 0.145% difference in imaging quality compared to the original. In conclusion, the optimized structure shows comprehensive advantages. Constructing the optical system components and the real physical environment of the site provides a valuable reference for the optimization and analysis of the mirror. [ABSTRACT FROM AUTHOR]

The impact of Hall current on the multiphase thermal transfer of an incompressible electrically conductive Jeffrey flow over an infinitely vertical plate when heat absorption and chemical reaction are present has been examined. Partial differential equations have been used to describe the process, accounting for heat and mass transfer effects. This study uses extended Fourier's and Fick's laws together with the recently announced constant proportional Caputo (CPC) fractional operator. The fractional model is converted into a nondimensional form by applying some appropriate quantities. The nondimensional produced fractional model for momentum, heat, and diffusion equations based on the CPC fractional operator has been calculated semi‐analytically by applying the Laplace method. The Mathcad 15 software to sketch the graphs for several factors, like the Grashof number, mass Grashof number, Schmidt number, Prandtl number, Hall, and magnetic field parameters, is used to describe the velocity profile. Additionally, a graphical explanation is provided for the influence of the appeared parameters, particularly the effect of the fractional parameters. It is concluded that the result of the fluid model developed by the generalized constitutive relations is more accurate and generalized than the results of the artificially contracted fractional model. A fractional derivative is therefore the ideal option to achieve controlled concentration, temperature, and velocity. The current study is immediately relevant to geophysical, cosmically fluid dynamics, medical, biological, and any other processes that are significantly enhanced by a low gas density and a high magnetic field. [ABSTRACT FROM AUTHOR]

The mathematical modeling of biological fluids holds paramount importance, given its diverse applications in the medical field. Understanding the peristaltic mechanism is crucial for gaining insights into various biological flows. This study focuses on numerically estimating the double-diffusive peristaltic flow of a non-Newtonian six constant Jefferys nanofluid within an irregular medium. The investigation considers the influences of nonlinear thermal emission, viscous dissolution, and induced magnetization, incorporating multiple slip conditions. The Buongiorno model is employed to underscore key features related to thermophoresis and Brownian diffusion coefficients. The convection of double diffusivity is elucidated through the Soret and Dufour variables. Lubrication technique is employed for mathematical simulation, and the resulting nonlinear coupled system of differential equations is solved numerically through the Mathematica program's built-in command (ND Solve function). The graphical representation of the impact of crucial flow variables, such as nanoparticle volume proportion, pressure gradient, solute density, temperature, pressure fluctuation per wavelength, and velocity distribution, provides valuable insight. The findings of the current study show that an increase in the Prandtl number and thermophoresis parameter leads to the expansion of thermal curves. Moreover, it is also noted that rising heat frequencies of radiation cause the concentration of nanoparticles to increase. [ABSTRACT FROM AUTHOR]

• A topology optimization framework applied to heat transfer with radiation has been developed using the Lumped Parameter Method. • The method is suitable for multi-case optimization, such as hot and cold configurations. • The performance is demonstrated by adding an additional copper layer with optimal shape to a Printed Circuit Board, improving the thermal compliance of its electronic components. • A model reduction technique is used to reduce the dimensionality of the optimized model while maintaining good accuracy. Designing thermal systems for space platforms is a challenging task due to the wide variability in thermal conditions during the orbit and the strict constraints imposed by other subsystems. Several strategies have been developed to address these challenges while minimizing the thermal control subsystem's signature, encompassing different algorithms optimize components positions in the platform. When relocation is not possible, thermal couplings between components can be modified to enhance heat transfer and achieve more uniform temperature distribution. To design optimal thermal paths in 2D space structures, in this paper a topology optimization framework based on the Heaviside Projection Method is introduced, using the Lumped Parameter Method (LPM) and taking the radiation heat transfer into account. The algorithm's performance is tested on a Printed Circuit Board (PCB) by designing an optimal copper layer to meet specific thermal requirements under both extreme hot and cold conditions. Results show a significant improvement in thermal compliance for all components with the addition of this high-conductivity layer. Additionally, a reduction method is introduced to transfer the material distribution from the optimization to a coarser mesh of any size, which is useful to facilitate its implementation in existing software, where a large number of degrees of freedom can be a limitation. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the Bödewadt boundary layer flow of ferrous oxide-based electrically non-conducting Nanofluid considering the influence of thermal radiation and viscous dissipation over a permeable disc with slip conditions. Here, viscosity is taken as a function of temperature and depth. The equation of energy incorporates the radiative heat flux as described by the Rosseland approximation. The Von Kármán Model alters the constitutive nonlinear coupled partial differential equations of motion, which include slip boundary conditions. The final system of equations in PDE is solved computationally using a shooting approach in MATLAB with ode45, and the results are elucidated, through graphs and tables. The effects of all the above-considered physical entities including the geothermal viscosity on the velocity profile and temperature distribution over the disc are examined. An exhaustive analysis of all the above-investigated results is presented for the record. It is observed that the geothermal viscosity with considered boundary conditions retards the motion of the fluid causing decay in the net molecular movement and the thermal diffusion. [ABSTRACT FROM AUTHOR]

The present study investigates experimental cooling from the ceiling using phase change materials (PCMs) in Yazd, a city characterized by a hot and dry climate. A one-fourth scale model of a real room, measuring 4 m × 3 m × 3 m, was employed for the analysis. To evaluate system performance and the impact of PCM on energy consumption reduction, three configurations were considered: a simple PCM system, a PCM system with a fan (PCM-F), and a PCM system with a mini cooler (PCM-C). Additionally, to assess the influence of window configurations on ventilation, temperature, and comfort conditions within the model, three scenarios were examined: two open windows, one open window, and no windows. The economic analysis compared the two systems with the fan and mini cooler against a full mechanical cooling system without PCMs. Furthermore, CO2 emissions and environmental impacts associated with the systems were also evaluated. The results indicate that the presence of PCMs in the ceiling, due to heat absorption during phase change, leads to a temperature reduction of 5 to 10 °C in the ceiling and a 3.2 °C reduction in the average room temperature compared to the scenario without PCMs. The findings demonstrate that ceiling cooling with PCMs significantly contributes to energy consumption reduction during peak hours of cooling demand. Specifically, the PCM-F system results in a 92% reduction, and the PCM-C system leads to a 71% reduction in total cost compared to the reference mechanical cooling system. Additionally, the PCM-F system achieves approximately a 36% reduction, and the PCM-C system results in a 34% reduction in environmental impact relative to the reference full mechanical cooling system. [ABSTRACT FROM AUTHOR]

There are numerous lakes in the Tibetan Plateau (TP) that significantly impact regional climate and aquatic ecosystems, which often freeze seasonally owing to the high altitude. However, the special warming mechanisms of lake water under ice during the frozen period are poorly understood, particularly in terms of solar radiation penetration through lake ice. The limited understanding of these processes has posed challenges to advancing lake models and improving the understanding of air–lake energy exchange during the ice-covered period. To address this, a field experiment was conducted at Qinghai Lake, the largest lake in China, in February 2022 to systematically examine thermal conditions and radiation transfer across air–ice–water interfaces. High-resolution remote sensing technologies (ultrasonic instrument and acoustic Doppler devices) were used to observe the lake surface changes, and MODIS imagery was also used to validate differences in lake surface conditions. Results showed that the water temperature under the ice warmed steadily before the ice melted. The observation period was divided into three stages based on surface condition: snow stage, sand stage, and bare ice stage. In the snow and sand stages, the lake water temperature was lower due to reduced solar radiation penetration caused by high surface reflectance (61% for 2 cm of snow) and strong absorption by 8 cm of sand (absorption-to-transmission ratio of 0.96). In contrast, during the bare ice stage, a low reflectance rate (17%) and medium absorption-to-transmission ratio (0.86) allowed 11% of solar radiation to penetrate the ice, reaching 11.70 W·m−2, which increased the water temperature across the under-ice layer, with an extinction coefficient for lake water of 0.39 (±0.03) m−1. Surface coverings also significantly influenced ice temperature. During the bare ice stage, the ice exhibited the lowest average temperature and the greatest diurnal variations. This was attributed to the highest daytime radiation absorption, as indicated by a light extinction coefficient of 5.36 (±0.17) m−1, combined with the absence of insulation properties at night. This study enhances understanding of the characteristics of water/ice temperature and air–ice–water solar radiation transfer through effects of different ice coverings (snow, sand, and ice) in Qinghai Lake and provides key optical radiation parameters and in situ observations for the refinement of TP lake models, especially in the ice-covered period. [ABSTRACT FROM AUTHOR]

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The co-combustion characteristics and thermodynamics of waste biomasses, namely coconut shell and corncob, with anthracite were investigated using TG-DTG/DSC analysis and artificial neural networks. TG-DTG experiments were conducted at different ratios of CS-AN and CC-AN, and the samples were heated from 293 K to 1273 K at heating rates of 10, 15, 20, 25, and 30 K·min−1. The results indicated three main stages in the combustion process of the mixtures and the combustion profiles shifted to higher temperatures with increasing heating rates. As the mass fraction of biomass in the mixtures increased from 10 wt.% to 90 wt.%, the residual mass of the co-combustion mixture decreased by 19.50 wt.% and 21.78 wt.% for CS-AN and CC-AN, respectively. The comprehensive combustion index of CS-AN increased from 24.645%2·min−2·K−3 to 167.274%2·min−2·K−3, while that of CC-AN increased from 26.262%2·min−2·K−3 to 102.654%2·min−2·K−3. The DSC results showed a peak of heat absorption followed by an exotherm in the co-combustion process. As the mass fraction of anthracite in the mixtures increased, the curve shifted toward the high temperature region and the exothermic time increased. The apparent activation energies (E) for CS, CC, and AN were 75.36, 112.08, and 90.90 kJ·mol−1, respectively. Additionally, 50 wt.% CS and 50 wt.% CC were more conducive to CS-AN and CC-AN co-combustion processes. 63 ANN models were utilized to predict the post-combustion residual weight of CS5-AN5. ANN56 was identified as the best performer, with error results (RSME = 1.482, MBE = 1.120, R2 = 0.9982) and a topology of (3 × 15 * 5 × 1), which proved to be the most suitable model for the co-combustion characteristics of this mixture. This study provides theoretical and practical guidance for solving engineering problems related to the energy utilization of waste biomasses (coconut shell and corncob) with anthracite. [ABSTRACT FROM AUTHOR]