Thermal radiation is inherently temporally and spatial incoherent. Precise control over thermal emission, especially achieving narrowband and highly directional radiation, is crucial for enhancing the energy conversion efficiency of photovoltaic systems, gas sensing, etc. However, the realization of a perfect narrowband thermal emitter capable of vertical emission with dual-polarization support remains a fundamental challenge. In this work, we demonstrate a dual-polarization narrowband thermal emitter operating in the vertical direction, leveraging the mechanism of lattice resonance. The proposed structure comprises an array of germanium (Ge) nanocylinders disposed on a silicon dioxide (SiO2) spacer layer and a gold substrate. It supports efficient narrowband thermal emission at 3222 nm for both transverse-electric (TE) and transverse-magnetic (TM) polarizations at normal incidence, with peak emissivities exceeding 97% in both cases. The emissivity exhibits a sharp decline when the angular deviation exceeds merely 0.2° (for TE) and 1° (for TM) from the surface normal, underscoring its exceptional emission directionality. Furthermore, we demonstrate the potential of this emitter for highly sensitive detection of methane and ammonia gases, as well as for refractive index sensing, offering new strategies for the design of high-efficiency thermal photonic devices.

The article deals with internal heat generation, nonlinear Darcy-Forchheimer MHD hybrid electrical conducting nanofluid ( SWCNT − A l 2 O 3 / H 2 O & MWCNT − CuO / H 2 O ) flow, thermal radiation, and defined mixed boundary constraints in a porous medium. Heat and mass transfer remain critical challenges in manufacturing and engineering applications. Therefore, adding nanoparticles to conventional fluids to enhance the thermal conductivity of base fluid and heat transfer efficiency is needed nowadays. This study examines the effects of radiation, magnetic influence, internal heat sources, and the inertial coefficient on the velocity and temperature profiles of a nanofluid flowing over a stretchable surface. The Von Karman similarity transformations are employed to transform the partial differential equations into ordinary differential equations. The primary results of the flow and heat transfer (HT) equations were obtained using the NDSolved command. Which is based on Runge–Kutta method. The computational technique allows for the extraction of numerical data, which is then converted into graphs to analyze the effects of key parameters on the profiles.

Abstract The discovery of heavy radioactive elements (e.g., $^{60}\mathrm{Fe}$) on Earth suggests that supernova explosions may have occurred near our planet within the past million years, potentially having a significant impact on the ecological environment. This finding has motivated the search for nearby neutron stars in the Solar neighborhood. In a recent study, a candidate for one of the closest neutron stars to Earth, LAMOST J235456.73+335625.9 (hereafter J2354), was reported. \textcolor{red}{Based on dynamical mass measurements under different inclination angle assumptions, the inferred mass range for the unseen compact companion in the system is $1.4$--$1.6$ $M_{\odot}$.} Hence, the unseen companion in J2354 is either a massive cold white dwarf or a neutron star. Here we model the flux variations of J2354 as a combination of ellipsoidal modulation and surface spots. We test both cold spot and hot spot models, setting the number of spots to two in each case, and constrain the spot properties through light curve fitting. In the cold spot scenario, the spots are mostly visible at phases $0.5$--$0.75$, whereas in the hot spot scenario, the spots appear predominantly at phases $0.25$--$0.5$. The hot spot model shows better agreement with the observed H$\alpha$ phase variation than the cold spot model. Furthermore, \textcolor{red}{the thermal radiation of} a massive but cold white dwarf \textcolor{red}{cannot} produce the level of localized heating required to explain the hot spot \textcolor{red}{unless additional heating mechanisms are involved}; in contrast, a neutron star can naturally provide such heating through energetic winds. Our results \textcolor{red}{are consistent with} the neutron star interpretation of the compact object in J2354.

Solar energy stands as one of the most promising green energy sources today. This paper proposes a symmetrical gap-type separated solar absorber and radiator (SETR) featuring a dielectric layer of Al2O3 and metal W as separation columns. Its unique structure enhances absorption within the effective solar energy spectrum, thereby alleviating solar energy absorption challenges. The finite difference time domain method (FDTD) results show that the SETR achieves an absorption rate of more than 90% in the 280–2096 nm band, which perfectly covers the visible light band range. The weighted average absorption in the 280–2500 nm band is 95.22% under AM1.5 conditions. The thermal emission efficiency at 1500 K is 95.13%, and the thermal radiation loss is less than 5%. Beyond analyzing the results, we also investigated the overall band absorption efficiency of the SETR under varying conditions by adjusting its structural parameters and physical parameters such as materials. This approach enables effective control over the absorption spectrum. Additionally, the proposed SETR is independent of polarization conditions. Both the TM and TE modes are insensitive to large incident angles. In the future, broadband SETRs can be applied to solar energy harvesting, thermoelectric conversion, and imaging fields, as it holds broad application prospects.

We investigate the transient behaviour of nanofluid flow in proximity to a vertically oriented plate oscillating around the -axis. A water-based nanofluid has been selected incorporating nanoparticles. The Laplace transform methodology has been employed to derive solutions to the governing equations pertinent to the problem. The vertical plate undergoes oscillatory motion along the -axis. The parameter denotes the stationary state of the plate, whereas corresponds to the forward and backward phases of its oscillation. The displacement of the oscillating vertical plate along the -axis is presented graphically through the velocity profiles. Utilizing MATLAB software, graphical representations are generated to clarify the implications of diverse physical parameters on the dynamics of the flow field. The findings elucidate complex flow phenomena, encompassing the effects of magnetic fields and solid volume fraction in diminishing the velocity of the nanofluid. The chemical reaction is observed to sequester thermal energy, resulting in a reduction in concentration attributable to factors such as temperature decline and solute degradation. Further variations in the skin friction coefficient, Nusselt number, and Sherwood number under the influence of various physical parameters are presented in tabulated form. The results indicate that the skin friction coefficient increases with increasing thermal radiation, as enhanced radiative heat transfer elevates the fluid temperature and intensifies momentum transfer in the vicinity of the wall. Additionally, a graphic comparison is made between the current and previous outcomes.

The maximum efficiency of extracting work from thermal radiation energy has been intensely studied. However, a large part of the world's energy resources is actually used for heating rather than work production. Therefore, finding the most effective way of heating by using radiation energy is another problem of great practical interest, not often studied. Here, it is demonstrated that such a way involves heat extractors. A general broadband theory based on the first and second laws of thermodynamics and the model of deformed blackbody radiation is developed for radiation-driven heating systems. Particular cases are considered under the assumption of local thermal equilibrium. Application to solar radiation heating shows that the photothermal heating efficiency may be improved. During a winter clear sky day, solar radiation-driven heat extractors may provide, in the ideal case, several times more heat per unit collection surface area than traditional solar heating. When constructed with current technology, heat extractors with evacuated tube solar collectors oriented toward the Sun under low-concentrated radiation may provide between 106% and 118% more heat per unit collection surface area than traditional solar heating. For an improved (mature) heat extractor technology, this range of values increases to about 130% to 337%, depending on ambient temperature. This makes the problem of radiation heating efficiency important from a practical point of view.

Abstract Accurate prediction of H2-blended combustion requires advanced radiation modeling as the radiation model plays a critical role in the turbulence–chemistry–radiation coupling inherent to such flames. To address the issue of accurately predicting the gas and soot thermal radiation characteristics in natural gas combustion blended with a high ratio of hydrogen, an improved global thermal radiation model based on the weighed-sum-of-gray-gases (WSGG) principle was proposed. The proposed model containing H2O and CO2 was developed based on a line-by-line (LBL) method using the HITEMP 2010 database. The coefficients were applicable to a total pressure range of 1–10 atm, a temperature range of 400–2500 K, a H2O/CO2 molar ratio range of 2.25–5, and a partial pressure path length range of 0.001–60 atm · m, verified using benchmark emissivity and a series of one- and two-dimensional heat transfer cases. The proposed WSGG model was then applied to the numerical simulation of a 40-kW combustion furnace. The results were compared with those obtained using a default model of fluent software, and the influence of soot radiation inclusion was discussed, indicating that pressurization and the presence of soot enhance radiative heat transfer, and the improved global model can perform more accurate medium radiation calculations compared to the previous model developed for conventional fuels, which provide a basis for furnace design of hydrogen-blended natural gas combustion.

The non-Newtonian fluid plays a crucial part in a wide range of uses, likely optimizing cooling technologies in electronic devices, improving drug delivery systems, and enhancing thermal management in reactors. However, the flow over the conducting Riga plate is used in controlling thermal and concentration boundary layers, which offers potential improvements in energy efficiency. The primary objective of the proposed analysis is to examine the radiative time-dependent buoyancy-driven Casson fluid across an electrically conducting slanted Riga plate, considering the impacts of a heat source and variable suction. For the thermal and solute transport phenomena, the effect of heat dissipation, thermal radiation, and chemical reaction is considered. The utilization of suitable dimensionless quantities plays a role in converting the governing equations into a set of partial differential equations in non-dimensional form. Further, these are numerically solved by utilizing the Finite Element Method in the Galerkin Weighted Residual Approach (FEM-GWRA) with linear interpolation functions. The variation of several characterizing parameters is presented through graphs. The significant outcomes include the Casson parameter and titled angle controls momentum boundary layer, while thermal diffusion and mass diffusion contribute to the mass and energy boundary layer thickness accordingly. However, the important findings are that the non-Newtonian Casson parameter manifests in two ways on the velocity distribution, and it favors a significant hike in the speed of the fluid close to the surface, but when the domain grows, the profile attenuates significantly. More precisely, the heavier species, along with the reacting parameter, act as a controlling parameter in restricting the fluid concentration. The validation of the current outcomes is also disclosed in good correlation in comparison with earlier investigations.

Peristaltic rheology of nanomaterial in a porous channel under thermal radiation and variable heat source: An artificial neural network framework

Tribodynamic behavior of two-phase Casson fluid in a rectangular channel with thermal radiation, Hall current, and ion slip effects

A simple ultra-wideband metamaterial solar absorber with near-perfect thermal radiation

One-dimensional diffusion spill fire flame thermal radiation model under upwind and downwind environments based on a discrete summation method for view factor calculation

Retraction notice to “Peristaltic transport of MHD Powell-Eyring nanofluid in an inclined channel with thermal radiation effects: Bio-medical applications in inclined channel” [Journal of Radiation Research and Applied Sciences 18 (2) (2025), 101517

Thermally tuned TE-polarized nonreciprocal thermal radiation at zero azimuthal angle with twisted Weyl semimetals

Curvature-enhanced thermal radiation in micro-structure

Retraction notice to “Hybrid nanofluid dynamics over an exponentially accelerating surface: Sensitivity to thermal radiation and chemical absorption” [Journal of Radiation Research and Applied Sciences, 18 (1) (2025), 101277

In modern engineering and biomedical applications, micropolar fluid with nanoparticles is gaining immense attention due to its ability to enhance thermal conductivity and provide better control over micro-scale behaviours. The present investigation explores the association of nanoparticle aggregation and dissipative heat on the time-dependent micropolar fluid flow, considering Maxwell effects in conjunction with the Brugman conductivity model. The system is subjected to an external magnetic field with surface suction imposed to regulate boundary layer behaviour. The study incorporates thermal radiation, non-Newtonian micropolar characteristics and time-dependent acceleration over a porous stretching/shrinking sheet. The present analysis accounts for Maxwell relaxation time representing fluid memory effects, while the Brugman model accommodates the influence of nanoparticle aggregation on effective thermal conductivity. The mathematical model presenting all these constraints is transformed into a dimensionless form by utilising standard transformation rules. The transformed model is tackled numerically, implementing the Runge–Kutta fourth-order technique with the shooting method. The comparative results with earlier established work are depicted in specific instances, and the essential findings of the study are reported as the fluid velocity is controlled by the factor suction velocity caused by the permeability of the surface and this leads to thinning in the surface thickness.

Abstract The global overuse of antibiotics has accelerated the spread of antibiotic resistance genes (ARGs) in water and food systems. While qPCR is widely used to monitor ARG degradation, its limitations in quantifying fragmented and unculturable ARGs hinder accurate comparisons. To address this, we implemented hydrogel digital loop-mediated isothermal amplification (LAMP)—a novel visual quantification platform enabling single-molecule detection by spatially confining LAMP reactions in hydrogel microchambers. This method was applied to evaluate the degradation kinetics of two critical ARGs (blaNDM from carbapenem-resistant E. coli and mecA from methicillin-resistant Staphylococcus aureus) under food-relevant treatments: heat, ultrasound, UV254, TiO₂ photocatalysis, and light exposure (red/blue/white). Results revealed that mecA exhibited higher thermal sensitivity than blaNDM, with degradation rates escalating at elevated temperatures. Ultrasound degraded most of both ARGs within 20 min, while UV254 achieved near-complete inactivation in 2 min. TiO₂ photocatalysis showed moderate efficacy, with mecA being more susceptible. Red light induced degradation via thermal radiation, whereas blue/white light had negligible effects within 60 min. Our hydrogel digital LAMP (dLAMP) system provides rapid, visual, and precise ARG quantification, offering significant potential for on-site monitoring in food safety control.

Purpose This study investigates the boundary-layer flow, heat transfer and mass transfer characteristics of a Casson-based hybrid nanofluid over a permeable stretching surface embedded in a porous medium. The analysis includes the effects of magnetohydrodynamics (MHD), Brownian motion, thermophoresis, thermal radiation and variable viscosity. Design/methodology/approach The hybrid nanofluid, composed of aluminum and silver nanoparticles suspended in a Casson base fluid, was modeled using a non-Newtonian rheological framework. The governing partial differential equations were transformed into a system of coupled, nonlinear ordinary differential equations via similarity transformations. This system was solved numerically using a fourth-order Runge–Kutta method combined with a shooting technique. Findings An increase in the Casson parameter enhances resistance to shear, thereby reducing the velocity profile. The Brownian motion (Nb) and thermophoresis (Nt) parameters significantly augment the thermal and concentration boundary layers, increasing wall heat and mass transfer rates by approximately 10–20% over baseline values. The magnetic parameter (M) reduces fluid velocity due to the Lorentz force but increases the temperature gradient at the wall, resulting in a steeper thermal boundary layer. A higher permeability parameter (K1) enhances thermal dispersion while simultaneously suppressing flow speed. An increase in the Prandtl number thins the thermal boundary layer, whereas an increase in the Schmidt number compresses the solutal boundary layer; both trends align with classical transport theory. The combined influence of these parameters reveals complex, nonlinear interactions within the system. Originality/value This study underscores the importance of multiphysics modeling in hybrid nanofluid systems. The extended insights provided can serve as a foundation for designing and optimizing microfluidic heat exchangers, MHD pumps, energy storage units and biomedical devices that utilize advanced nanofluidic flows.

Purpose The growing demands for efficient cooling systems, lubrication and anti-friction properties motivate the investigation of advanced heat transfer in fluid dynamics. The purpose of this study is to investigate the convective flow of ternary hybrid nanofluids around a vertical cylinder, considering the effects of a porous medium, magnetic field, thermal radiation, viscous dissipation and Darcy–Forchheimer influence on heat transfer and fluid velocity. Design/methodology/approach Introduce the similarity transformations to reduce the system of governing partial differential equations (PDEs) to a system of nonlinear ordinary differential equations (ODEs), which are then converted into linear first-order ODEs. The bvp4c solver in MATLAB is used to crack the transformed ODEs and for the graphical illustrations. Findings The combined effects of radiation, Biot number and Eckert number significantly enhance the heat transfer capabilities of ternary hybrid nanofluids, achieving a 17.533% improvement over nanofluids alone. The effects of porosity, Darcy–Forchheimer influence and the magnetic field on fluid motion and skin friction are also investigated and presented in detail. This study has broad applications in cooling systems for power plants, as well as in anti-friction properties for transportation, automotive, precision machinery, robotics engineering and lubrication in rotating machinery, polymers and textile engineering. Originality/value From the literature survey, it is noted that the simultaneous effects of magnetic field, thermal radiation, viscous dissipation and convective boundary conditions on Darcy–Forchheimer flow of ternary hybrid nanofluids around a vertical cylinder have not been investigated so far, and this study addresses this gap. Further, the results are validated and compared with the existing results as a special case.