Radiation Conditions Research Articles

Magnetohydrodynamic stagnation point flow of Williamson hybrid nanofluid via stretching sheet in a porous medium with heat source and chemical reaction

The stagnation point flow of non-Newtonian fluids has several engineering and industrial applications. In this article, we considered the investigation of the magnetohydrodynamic stagnation point flow of Williamson hybrid nanofluid with chemical reaction and energy generation effects over a porous extending sheet. Similarly, the characteristics of radiation and convective boundary conditions are also taken. Presumptions of boundary layer movement of Williamson hybrid nanofluid facilitate the simplification of the essential mathematical equations for the conservation of mass, energy, momentum and concentration. By introducing the similarity variables, the controlling partial differential equations have been transformed into dimensionless ordinary differential equations. Then, the most effective homotopy analysis method is used to approximate the solutions of reduced ordinary differential equations. Graphical calculations are carried out for hybrid nanofluid [Formula: see text] and nanofluid [Formula: see text]. To investigate the impacts of leading parameters, graphs for the quantities are generated. At the boundary, the local skin friction factor, the Sherwood number and the Nusselt number are also determined. According to the outcomes, it is discovered that when the porosity parameter increases the velocity profile of the hybrid nanofluid [Formula: see text] climbs above that of the nanofluid [Formula: see text]. An increase in thermal radiation parameter and Biot number causes a greater thickness of the thermal boundary layer, which in turn raises the temperature of the hybrid nanofluid. Furthermore, the increased chemical reaction decreases the concentration in both [Formula: see text] hybrid nano liquid and [Formula: see text] mono nanofluid cases.

An experimental evaluation of drying banana slices using a novel indirect solar dryer under variable conditions

Novel thermal characteristics of drying banana slices in an indirect dryer are presented for four different experimental drying conditions in the forced convection mode. The novel characteristics include measuring the airflow velocity in the drying chamber, measuring the thermal profiles in different trays comprehensively and measuring the relative humidity under different conditions. Two tests are carried for 16 h in two consecutive days (8 h per day for each test). The first test is on acloudy day followed by a sunny day, while the second test is carried out on two consecutive sunny days. Tests 3 and 4 are 24 h tests with high (0.23 m/s) and low (0.11 m/s) average drying chamber airflow velocities under good solar radiation conditions. The maximum temperatures obtained in the collector and the drying chamber are around 80 and 48 °C, respectively, for the 16 h tests. Significantly lower collector and drying chamber temperatures are obtained due to cloudy conditions. Maximum collector temperatures are around 84 and 95 °C for the high and low average airflow chamber velocities for the 24 h tests. The corresponding maximum temperatures in the drying chamber are around 50 °C for the 24 tests. The final moisture ratios are 0.26 (cloudy and sunny days) and 0.20 (two sunny days), respectively, for the 16 h tests. These final moisture ratios are lower than those obtained for the 24 h tests which are 0.32 and 0.28, respectively. Increasing the drying chamber airflow velocity results in faster moisture removal during sunshine hours for the 24 h tests. For tests 1, 2, 3 and 4, the maximum average collector efficiencies during the sunshine period are around 60, 80, 40 and 10 %, respectively. The average drying efficiencies for the total solar drying period for tests 1,2,3 and 4 on day 1 are 6.9, 6.9, 5.5 and 5.7 % respectively. These values are comparable, suggesting that the average collector powers, airflow velocities and efficiencies have a very small effect on the average solar drying efficiency for the whole drying period. The quality of the bananas slices mainly in terms of the colour and shape is also compared with previous studies and commercially available products. A reasonably acceptable quality product is obtained.

Методы и средства восстановления спектров излучения по пространственным распределениям

The paper considers the principles of construction of non-classical radiation spectrometers. Schemes for the formation of spatial distributions of radiation fields are presented, and the problem of reconstructing the spectra from attenuation curves and profiles of secondary radiation fields is formulated. A review of non-classical spectrometers is presented and a systematization of non-classical radiation spectrometers is proposed based on the principle of obtaining information about the primary radiation beam. A technique for determining radiation conditions from reconstructed spectral distributions is described.

An alternative potential method for mixed steady‐state elastic oscillation problems

We consider an alternative approach to investigate three‐dimensional exterior mixed boundary value problems (BVPs) for the steady‐state oscillation equations of the elasticity theory for isotropic bodies. The unbounded domain occupied by an elastic body, , has a compact boundary surface , which is divided into two disjoint parts, the Dirichlet part and the Neumann part , where the displacement vector (the Dirichlet‐type condition) and the stress vector (the Neumann‐type condition) are prescribed, respectively. Our new approach is based on the classical potential method and has several essential advantages compared with the existing approaches. We look for a solution to the mixed BVP in the form of a linear combination of the single‐layer and double‐layer potentials with densities supported on the Dirichlet and Neumann parts of the boundary, respectively. This approach reduces the mixed BVP under consideration to a system of boundary integral equations, which contain neither extensions of the Dirichlet or Neumann data nor the Steklov–Poincaré‐type operator involving the inverse of a special boundary integral operator, which is not available explicitly for arbitrary boundary surface. Moreover, the right‐hand sides of the resulting boundary integral equations system are vector functions coinciding with the given Dirichlet and Neumann data of the problem in question. We show that the corresponding matrix integral operator is bounded and coercive in the appropriate ‐based Bessel potential spaces. Consequently, the operator is invertible, which implies unconditional unique solvability of the mixed BVP in the class of vector functions belonging to the Sobolev space and satisfying the Sommerfeld–Kupradze radiation conditions at infinity. We also show that the obtained matrix boundary integral operator is invertible in the ‐based Besov spaces and prove that under appropriate boundary data a solution to the mixed BVP possesses ‐Hölder continuity property in the closed domain with , where is an arbitrarily small number.

Analysis of the heat transfer enhancement in water-based micropolar hybrid nanofluid flow over a vertical flat surface

Abstract This article presented micropolar hybrid nanofluid flow comprising copper and alumina nanoparticles over a flat sheet. The mixed convection phenomenon is studied under the effect of gravity. Some additional forces such as magnetic field, thermal radiation, Eckert number, heat source, and thermal slip condition are adopted in this analysis. The leading equations are transformed into dimensionless format by employing appropriate variables and then evaluated by homotopy analysis method (HAM). The obtained results are compared with published results and found a good agreement with those published results. Also, the results of HAM are compared with those of numerical method and found a good agreement as well. The fluctuations within the flow profiles are showcased utilizing figures and tables, followed by an in-depth discussion and analysis. The outcomes of this work show that the higher volume fractions of copper and alumina nanoparticles improved the hybrid nanofluid viscosity, which results in the augmenting variation in the velocity profiles. The higher volume fractions of copper and alumina nanoparticles improved the hybrid nanofluid thermal conductivity, which results in the augmenting variation in thermal distribution. The growing mixed convection factor amplifies the buoyancy force toward the stagnation point flow, which enlarges the velocity panel. The effects of hybrid nanoparticles (Cu-Al2O3/water) at the surface are smaller on friction force and larger in case of thermal flow rate when compared to the nanofluids (Cu/water and Al2O3/water).

MHD radiative Gr-Ag-TiO2/H2O ternary hybrid nanofluid flow upon a permeable movable wedge with irreversibility analysis

ABSTRACT The mass-based ternary hybrid nanofluid model is applied for the magnetohydrodynamic (MHD) flow over a moving wedge with wall permeability, thermal radiation, and convective boundary condition. The masses of the nanoparticles and the base fluid are considered instead of the volumetric concentration of the first, the second, and the third nanoparticles. In the base fluid of water, three types of nanoparticles such as titania, silver, and graphene have been embedded. A similarity method is used to reduce variables and also to turn prominent equations of ternary hybrid nanofluid flow into a simplified form. The shooting technique with the Runge-Kutta-Felhberg method has been used to numerically solve the converted boundary layer equations. The largest Nusselt number is related to the ternary hybrid nanofluid, in which a heat transfer enhancement of 6.55% has been obtained in comparison with regular fluid. The Nusselt number for five shapes of the third nanoparticles is obtained (when both the first and second nanoparticles are spherical), and when the third nanoparticle has the shape of the disk, the most heat transfer has occurred. The highest entropy generation is related to the stagnation point case (m = 1) and the lowest belongs t the downhill case (m = –0.0825).

Effect of electromagnetic radiation on the electronic and thermoelectric properties of armchair edge silicene nanoribbons

We theoretically investigate the influence of electromagnetic radiation on the electronic and thermoelectric properties of armchair edge silicene nanoribbons. Specifically, we study the effects of varying the polarization (s or p) and incident angle (0, 30, 45, 60, and 90°) of radiation on the band structure, transmission function, density of states, Seebeck coefficient, and electronic figure of merit (ZTe) of the nanoribbons. Our results demonstrate that the electronic properties are highly dependent on radiation conditions due to their influence on electron transport. We find that the transmission function and density of states exhibit distinct polarization-dependent behaviors that highlight the role of the radiation's electric field orientation. Importantly, the ZTe shows significant modulation with the incident angle for both polarizations, achieving optimized values up to 0.18. These findings provide insights into controlling the electronic and thermoelectric properties of silicene nanoribbons using electromagnetic radiation. Our work underscores opportunities for developing silicene-based nanophotonic devices with enhanced performance through all-optical means. The demonstrated tunability via irradiation paves the way for potential applications such as optical switches, sensors, and next-generation optoelectronics using silicene nanoribbons.

Data-based investigation of the effects of canopy structure and shadows on chlorophyll fluorescence in a deciduous oak forest

Abstract. Data from satellite, aircraft, drone, and ground-based measurements have already shown that canopy-scale sun-induced chlorophyll fluorescence (SIF) is tightly related to photosynthesis, which is linked to vegetation carbon assimilation. However, our ability to effectively use those findings are hindered by confounding factors, including canopy structure, fluctuations in solar radiation, and sun–canopy geometry that highly affect the SIF signal. Thus, disentangling these factors has become paramount in order to use SIF for monitoring vegetation functioning at the canopy scale and beyond. Active chlorophyll fluorescence measurements (FyieldLIF), which directly measures the apparent fluorescence yield, have been widely used to detect physiological variation of the vegetation at the leaf scale. Recently, the measurement of FyieldLIF has become feasible at the canopy scale, opening up new opportunities to decouple structural, biophysical, and physiological components of SIF at the canopy scale. In this study, based on top-of-canopy measurements above a mature deciduous forest, reflectance (R), SIF, SIF normalized by incoming photosynthetically active radiation (SIFy), FyieldLIF, and the ratio between SIFy and FyieldLIF (named Φk) were used to investigate the effects of canopy structure and shadows on the diurnal and seasonal dynamics of SIF. Further, random forest (RF) models were also used to not only predict FyieldLIF and Φk, but also provide an interpretation framework by considering additional variables, including the R in the blue, red, green, red-edge, and near-infrared bands; SIF; SIFy; and solar zenith angle (SZA) and solar azimuth angle (SAA). Results revealed that the SIF signal is highly affected by the canopy structure and sun–canopy geometry effects compared to FyieldLIF. This was evidenced by the weak correlations obtained between SIFy and FyieldLIF at the diurnal timescale. Furthermore, the daily mean SIF‾y captured the seasonal dynamics of daily mean F‾yieldLIF and explained 58 % of its variability. The findings also revealed that reflectance in the near-infrared (R-NIR) and the NIRv (the product of R-NIR and normalized difference vegetation index (NDVI)) are good proxies of Φk at the diurnal timescale, while their correlations with Φk decrease at the seasonal timescale. With FyieldLIF and Φk as outputs and the abovementioned variables as predictors, this study also showed that the RF models can explain between 86 % and 90 % of FyieldLIF, as well as 60 % and 70 % of Φk variations under clear-sky conditions. In addition, the predictor importance estimates for FyieldLIF RF models revealed that R at 410, 665, 740, and 830 nm; SIF; SIFy; SZA; and SAA emerged as the most useful and influential factors for predicting FyieldLIF, while R at 410, 665, 705, and 740 nm; SZA; and SAA are crucial for predicting Φk. This study highlighted the complexity of interpreting diurnal and seasonal dynamics of SIF in forest canopies. These dynamics are highly dependent on the complex interactions between the structure of the canopy, the vegetation biochemical properties, the illumination angles (SZA and SAA), and the light conditions (ratio of diffuse to direct solar radiation). However, such measurements are necessary to better separate the variability in SIF attributable to radiation and measurement conditions from the subtler variability attributable to plant physiological processes.

Highly luminescent CsPbX3@MIL-53(Al) nanoarchitectonics with anomalous stability towards flexible emitting films

The poor stability of perovskite nanomaterials exposed in high temperature, moisture, light radiation, and polar solvent conditions severely restrict their commercial application. To address this issue, the growth in situ of CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) is carried out by using the stable aluminum (Al)-based metal-organic frameworks to create CsPbX3@MIL-53(Al) composites. Compared with pristine CsPbX3 NCs prepared using room temperature ligand assisted re-precipitation synthesis, the CsPbX3@MIL-53(Al) composites exhibit narrow photoluminescence (PL) spectra and greatly improved stability. The green emitting CsPbBr3@MIL-53(Al) composite exhibit narrowed PL spectrum (the full width at half-maximum of PL spectra: 20 nm for the composite and 28 nm for CsPbBr3 NCs) and a blue-shifted PL peak wavelength (517.6 nm for the composite and 527.6 nm for the CsPbBr3 NCs). The relationship of microstructure, components, PL, fluorescence lifetime, and stability are discussed systematically. Anomalous stability against heat-treatment, polar solvent and humidity conditions indicated the composites retained their initial PL intensity after storge more than 4 months in ambient conditions and heat-treated to 120ºC for 5 cycles. The emitting color of CsPbBr3@MIL-53(Al) composites are easily adjusted from blue, green to red by controlling the halide components of precursors. The composite was used to create emitting coating and highly bright flexible emitting films which also reveal high stability, suggesting that in situ encapsulation of CsPbX3 NCs in MIL-53(Al) would supply a novel platform for various emitting devices.

Microstructural changes in GaN and AlN under 950 MeV Au swift heavy ion irradiation

The radiation hardness of GaN-based devices is a critical metric for applications in extreme environments. This study investigates the structural changes in GaN and AlN induced by swift heavy ion (SHI) irradiation, characteristic of space radiation environments. A multilayered GaN/AlN structure is exposed to 950 MeV Au ions at fluences of 1×1012 and 8×1012 ions/cm2. Subsequent post-irradiation characterization, including transmission electron microscopy and energy-dispersive x-ray spectroscopy, reveal no apparent amorphization across the entire sample. Notably, significant nanometer-sized cavities are observed in both GaN and AlN. The cavities in GaN exhibit an increase in number density and diameter with increasing SHI irradiation, with the average diameter progressing from 1.80 to 2.10 nm. In contrast, cavities in AlN appear considerably smaller. Molecular dynamics simulations, coupled with the inelastic thermal spike model, reproduce the presence of cavities in GaN and no cavities in the AlN structure. This difference is attributed to the faster heat dissipation and stronger bonding in AlN. Considering the overlapping of ion impacts at high fluences, simulations confirm the enlargement of cavity size in GaN. These findings contribute to a mechanistic understanding of the contrast in ion–matter interactions and induced microstructures between AlN and GaN under extreme ionizing radiation conditions. This disparity could potentially impact electronic performance through the formation of defect traps and interfacial strain fields.

The effect of litter decomposition mostly depends on seasonal variation of ultraviolet radiation rather than species in a hyper-arid desert

Introduction: Ultraviolet (UV) radiation is believed to play a significant role in accelerating litter decomposition in water-limited ecosystems. Litter traits also influence the decomposition. However, the dominance of litter traits and ultraviolet radiation on litter decomposition in hyper-arid deserts (annual precipitation: potential evaporation < 0.05) with diverse species and seasonal variations remain unclear.Methods: To address this knowledge gap, we examined the decomposition of three dominant litter species (Karelinia caspia, Alhagi sparsifolia, and Populus euphratica) in the southern edge of the Taklimakan Desert, Northwest China.Results: Our results revealed that under UV radiation conditions, K. caspia, A. sparsifolia, and P. euphratica experienced mass losses of 45.4%, 39.8%, and 34.9%, respectively, and 20%, 22.2% and 17.4%, respectively under UV filtering treatment. Specifically, the loss rate of carbon and lignin under UV radiation, was 2.5 and 2.2 times higher than under UV filtering treatment, respectively.Conclusion: UV radiation did not dominate decomposition throughout the year in our study area, and the loss rate of litter traits was significantly higher in summer than in winter under UV radiation. Moreover, this photodegradation is related to the intensity of UV exposure, but not to precipitation or temperature. Surprisingly, species type had no significant effect on litter decomposition. However, when we applied a UV filtering treatment, we observed higher loss rates of nitrogen compared with the ambient treatment, suggesting the involvement of other spectra in the litter decomposition process. Overall, our findings elucidate that UV radiation is a crucial factor that affects litter mass loss. The magnitude of this effect mostly varies with the season rather than the species of litter.

Impact of DC-DC Converters on the Energy Performance of a Dense Concentrator PV Array under Nonuniform Irradiance and Temperature Profiles

Efficiency losses resulting from electrical mismatching in densely packed photovoltaic arrays present a significant challenge, particularly exacerbated in nonuniformly illuminated receivers and under varying temperatures. Serial configurations are particularly susceptible to radiation nonuniformities, while parallel systems are negatively affected by temperature variations. Various authors have recommended the incorporation of electrical voltage and current sources to mitigate these losses. This study explores different electrical connection configurations utilizing concentrated photovoltaic (CPV) cells and DC-DC electrical current converters. A self-adaptive microfluidic cell matrix cooling system is employed to mitigate thermal dispersion caused by the highly nonuniform illumination profile. The obtained results for each configuration are compared with the total electrical power produced by individual cells, operating under identical radiation and temperature conditions to those of the entire array. The results reveal a noteworthy increase in production across all studied configurations, with the parallel–series arrangement demonstrating the most promising practical utility. This configuration exhibited a remarkable 50.75% increase in power production compared with the standard series connection.

Molecular dynamics simulation study of the effect of Ce4+ incorporation at Zr site on the threshold displacement energy in Y4Zr3O12 material

ABSTRACT This study utilizes classical molecular dynamics (MD) simulations to examine the structure and the impact of cerium (Ce4+) incorporation, serving as a surrogate for plutonium (Pu), at the zirconium (Zr4+) site on the threshold displacement energy (Ed) for each atom within the δ-phase Y4Zr3O12 material along 100 different directions. The minimum Ed values obtained for Y, Zr, and O in Y4Zr3O12 are 50 eV, 60 eV, and 25 eV, respectively. Notably, the Y cation is more prone to displacement than the Zr cations, while oxygen anions are even more easily displaced than cations, requiring less energy for displacement. Furthermore, the incorporation of Ce4+ at the Zr4+ site in the Y4Zr3-3xCe3xO12 (0 ≤ x ≤ 0.5) system reduces both the minimum and average Ed values for Zr atoms. The presence of Ce also decreases the minimum Ed for Y at x = 0.5 and for OI at x = 0.125, while increasing the minimum Ed for OII at x = 0.25. These findings suggest that the incorporation of Ce can influence the radiation resistance of the Y4Zr3O12 material, thereby offering insights into potential strategies for enhancing its performance under radiation conditions.

Synergistic impacts of radiative flow of Maxwell fluid past a rotating disk with reactive conditions: An Arrhenius model analysis

This study presents an analysis of the hydromagnetic radiative flow of a Maxwell fluid past a rotating disk around its own axis with an angular velocity Ω0 which has enormous applications in metal casting (help to optimize the solidification and cooling of molten metals), plastic molding and aerospace engineering (cooling system of aircraft engines). The flow is constrained by boundaries that induce convection and chemical reactions described by the Arrhenius model. By applying similarity transformations, the non-linear partial differential equations, which describe the flow phenomenon, are metamorphosed into the non-dimensional system of ordinary differential equations (ODEs). The obtained ODEs are then solved numerically using ‘Keller box method’, an efficient computational technique, by implementing the finite-difference approach. The influence of different parameters, namely magnetic field strength, radiation parameter, reaction rate constant, and convective heat transfer coefficient, on the flow and heat/mass transfer characteristics are investigated. The findings suggest that the higher activation energy leads to a slower rate of reaction. As the reaction rate decreases, the consumption of reactant molecules and the reduction in their concentration also slow down. The influence of the convective heat transfer coefficient is also examined in terms of its effect on the thermal and concentration boundary layers. As the stretching parameter increases, the Maxwell fluid undergoes greater deformation, leading to greater strain and a consequent slowing of the fluid's radial velocity. Heat transfer is enhanced by thermal radiation and convective condition at the surface of rotating disk. The findings of this study provide valuable insights into the industries dealing with Maxwell fluids, enabling them to enhance process efficiency, optimize resource utilization, and develop sustainable and environmentally friendly solutions.

Triple-diffusive free convection enhancement at the stagnation point on moving sheet under the influence of hall effect and mass flux

This study seeks to examine the impact of convective heat transfer, buoyancy ratios, hall current effect, nonlinear thermal radiation, Schmidt number, Prandtl number and mass flux condition on the temperature profiles, velocity profiles and concentration profiles. The research explores into mass and heat transfer characteristics of a stagnation point flow of a free convective triple diffusion with considerations for convective boundary constraints and nonlinear thermal radiation over a mobile vertical plate. To elucidate the aims and methodology, the study utilizes similarity transformation to convert the governing partial differential equations into a set of nonlinear ordinary differential equations. Numerical solutions are obtained employing a fourth-order Runge-Kutta shooting strategy. The findings, showcased through graphical representations, unravel the intricate interplay of parameters, shedding light on flow distribution, temperature, and velocity profiles. These quantitative results not only enhance our scientific understanding of fluid dynamics but also hold practical implications across diverse sectors. Notably, the acquired insights are poised to benefit fields such as environmental science and engineering, where optimizing heat and mass transfer processes is paramount. This research thus contributes valuable perspectives to both the theoretical framework of fluid dynamics and its real-world applications.

Prediction of Non-Stationary Multi-Head Cloud Motion Vectors for Intra-Hourly Satellite-Derived Solar Power Forecasting

Solar photovoltaic (PV) power has become one of the major renewable energy sources in modern power systems. Hence, solar forecasting is indispensable for addressing the uncertainties of PV power outputs. Since PV power generation mainly depends on solar radiation conditions, satellite-derived methods have been proven effective in large-scale short-term solar forecasting. These methods utilize satellite optical images to track cloud motion and do not require supplemental ground cameras. However, cloud motion between two consecutive satellite images is highly non-stationary, as the motion includes both displacement and shape variation. Conventional motion estimation methods may miss the detailed cloud variation information, increasing the errors in solar forecasting. In this study, a multi-head cloud motion vector prediction method is proposed to address this challenge. The method models cloud variation as the probabilistic sum of pixels moving under multiple optical flow vectors. Time-varying solar intensity is also considered in the method. In order to estimate these optical flow vectors, a learning-based intelligent model with a self-attention structure is established. The proposed method of multi-step-ahead satellite-derived solar forecasting is superior to conventional methods, as the results of case studies indicate that the proposed method improves the precision of intra-hourly PV power prediction.

Radiation Data Analysis Tool (RaDAT)

Radiation Data Analysis Tool (RaDAT), developed under a specific task order of ITER project, was designed using Matlab and it is a GUI (Graphical User Interface)-based compact application intended to support expert and non-expert users in: (1) visualization analysis of 2D radiation maps, (2) radiation qualifications of electronic equipment and (3) Occupational Radiation Exposure (ORE) analysis.It was certified for Protection Important Activities (PIA) and authorized to be used for equipment radiation qualification activities. Its main functionalities allow: (1) to visualize quickly 2D radiation maps (.VTR/.VTK files) on different planes and positions, investigating radiation conditions in different spots of the Tokamak Complex Building (TCB); (2) to analyse automatically radiation conditions of lists of millions of equipment volumes (.STL files), providing the best and the worst radiation conditions on Excel tables; (3) to calculate the total biological dose cumulated by a worker along a specific route, passing from a workstation to another, in the TCB. Another feature implemented in RaDAT is the Flexibility Radius (FR) option, which could be applied to the volumes, extending them by this FR, in order to take into account any possible relocation in proximity of the nominal installation spot.RaDAT allows reducing the analysis time considerably. It is capable to analyse one radiation map, finding the best and the worst radiation conditions within a single volume (e.g.: an electrical enclosure) in ∼ 50 ms, using a standard office laptop, reducing the analysis time by a factor ∼1000, compared to a manual analysis approach on standard visualization tools.

Role of Planetary Radius on Atmospheric Escape of Rocky Exoplanets

Large-scale characterization of exoplanetary atmospheres is on the horizon, thereby making it possible in the future to extract their statistical properties. In this context, by using a well-validated model in the solar system, we carry out 3D magnetohydrodynamic simulations to compute nonthermal atmospheric ion escape rates of unmagnetized rocky exoplanets as a function of their radius based on fixed stellar radiation and wind conditions. We find that the atmospheric escape rate is, unexpectedly and strikingly, a nonmonotonic function of the planetary radius R and that it evinces a maximum at R ∼ 0.7 R ⊕. This novel nonmonotonic behavior may arise from an intricate trade-off between the cross-sectional area of a planet (which increases with size, boosting escape rates) and its associated escape velocity (which also increases with size but diminishes escape rates). Our results could guide forthcoming observations because worlds with certain values of R (such as R ∼ 0.7 R ⊕) might exhibit comparatively higher escape rates when all other factors are constant.

Transformer oil‐based Casson ternary hybrid nanofluid flow configured by a porous rotating disk with hall current

AbstractThe present work examines the 3D, incompressible, magnetohydrodynamic, mixed convective, and Darcy‐Forchheimer Casson /transformer oil ternary hybrid nanofluid flow configured by a porous rotatory disk. This research work takes into account the influences of hall current, thermophoresis, heat absorption/generation, Brownian motion, joule heating, chemical reaction, thermal radiation, activation energy, and velocity slip condition. The administrative partial differential equations (PDEs) that expound the problem are modified into a set of ordinary differential equations (ODEs) by imposing a similarity conversion, which is further solved numerically by adapting the worthy bvp4c scheme. The velocity, thermal, and mass profiles are delineated through graphs, and the features of skin friction coefficient, heat, and mass transmission are also explicated thoroughly via tables. One significant observation of this research is that the Casson parameter weakens transversal velocity whereas a reverse tendency is noticed against the radial velocity. Our obtained outputs affirm that Casson ternary hybrid nanofluid has respectively 10.93 % and 8.86% higher heat deliverance rate when compared to Casson nanofluid and Casson hybrid nanofluid. Besides, the Casson ternary hybrid nanofluid has respectively 33.68 % and 27.52% higher mass deliverance rate when compared to the Casson nanofluid and Casson hybrid nanofluid. Also, the sturdy values of the Casson parameter lessen the skin friction coefficient. The inferences derived from our research may advantageously be used in rotating types of machinery, medical equipment, gas turbine rotators, etc.

Changes in Physiological Indices, Amino Acids, and Volatile Compounds in Vitis vinifera L. cv. Pinot Noir under UV-B Radiation and Water Deficit Conditions.

UV-B radiation and water deficit can challenge Pinot noir growth and fruit quality. The aim of this work is to determine the effects of UV-B and water deficit on the physiological indices, amino acids, and volatile compounds of Pinot noir vine and fruit. The results showed that both individual and combined treatments caused a decrease in the leaf SPAD, with the largest amplitude being observed in the combined treatment. Water deficit also decreased the leaf water potential and increased the juice δ13C‱ at harvest, which was the opposite of the latter under UV-B radiation. Interestingly, most of the physiological indices under combined stresses did not show significant changes compared with that under no UV-B and the well-watered control treatment. Moreover, the concentrations of amino acids and volatile compounds in the berries were determined at harvest. The amino acid contents were significantly increased by the combined treatment, particularly proline (Pro), aspartate (Arg), alanine (Ala), and threonine (Thr). There were slight increases in volatile compounds. This research substantially contributed to improve our scientific understanding of UV-B and water deficit responses in an important commercial species. In addition, it highlighted some future research to produce high-quality wines with the anticipated specific characteristics.