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Ultrashort pulse (USP) lasers provide a novel approach to microwave production for remote applications. In this scheme, the plasma produced in the interaction of a USP with a material surface at a distance serves as a localized source of radio frequency (RF) radiation. Ultrashort pulses allow for the long-range projection of high-intensity light (∼1013 W/cm2), through the phenomenon of laser filamentation, thereby enabling the efficient generation of transient plasmas on remote material surfaces. In this paper, the mechanism of RF production in the laser–matter interaction is discussed and experimental characterization of the RF emission in a variety of target geometries is presented. Both transient dipole radiation and resonance absorption are discussed as theoretical mechanisms of RF generation. Furthermore, spectral composition of the RF emission, angular distribution of the emission, and dependence of the RF on laser focusing conditions are all characterized for a number of target materials in the single to tens of GHz range, using microwave horn antennas in conjunction with heterodyning electronics. [ABSTRACT FROM AUTHOR]

Efficient absorption of solar radiation holds the key to photothermal utilization; however, realizing solar absorber designs with high absorption efficiency remains challenging. Herein, a nickel-based metamaterial selective solar absorber with a nanopillar array structure was proposed to realize nearly perfect optical absorption over a broad spectrum. The average absorbance is up to 96% in the 300–2033 nm wavelength range. Notably, a reasonably detailed analysis of the physical mechanism of the proposed absorber was performed in this paper, attributing the exceptional broadband absorption to the concurrent interaction with surface plasmon resonance, quarter-wavelength resonance, and electric dipole resonance. The absorption efficiency declines significantly when λ > 2.5 μm, with only 20% absorptivity at λ = 6 μm in the radiation-absorbing transition region. This decline is desirable, as it contributes to reducing the emissivity in the mid-infrared range and, therefore, prevents self-radiation. The results demonstrate that the selective absorber possesses the potential to capture solar energy within a broadband, while avoiding undesirable self-radiation, thereby enhancing the integral efficiency of the solar energy conversion system. Moreover, the absorption spectrum shows insensitivity to polarization and angle of incidence. The selective solar absorber proposed here offers excellent performance with a simple structure, showing great promise in the field of photothermal conversion. [ABSTRACT FROM AUTHOR]

This study presents a detailed investigation into the structural, thermal, and radiation shielding properties of a new glass composition, labeled as (50-x)B 2 O 3 + 30TeO 2 + 10Bi 2 O 3 + 10CdO + x Tm 2 O 3 (where x = 0, 1, 2, 3, 4, 5 mol %). Various radiation shielding parameters such as mass attenuation coefficient, linear attenuation coefficient, half-value layer, mean free path, effective atomic number, and absorbed equivalent dose rates for neutrons were determined through experimental measurements. The study also employed theoretical calculations to assess the exposure buildup factor and effective removal cross-section for neutrons. Additionally, the SRIM program was utilized to investigate mass stopping power and projected range for proton and alpha particles. The structural characteristics of the glasses were analyzed using XRD and FT-IR, while thermal properties were examined through Differential Thermal Analysis (DTA). FTIR analysis revealed distinctive bands corresponding to Bi—O, B—O—B, and Te—O bonds. Glass transition temperatures (T g) increased with Tm 2 O 3 content, ranging from 422 °C to 444 °C. The radiation shielding properties of bismuth boro-tellurite glasses showed that a dose of 1.2025 μSv/h emitted from a fast neutron source was absorbed by 35.1574 % in pure glass and 40.0391 % in glass doped with 5 mol% Tm 2 O 3. Incorporating Tm 2 O 3 into the glass matrix significantly improved the shielding and thermal properties, thus enhancing their potential for advanced high-energy radiation absorption. This investigation contributes to a deeper understanding of how Tm 2 O 3 enhances the structural and thermal attributes of these glasses, positioning them as promising materials for radiation shielding applications. [ABSTRACT FROM AUTHOR]

The combined effects of diffusion-thermo and radiative absorption on free convective hydromagnetic heat-generating chemically reactive flow of Cu-water nanofluid past an instantaneously accelerated unlimited vertical plate nested in a porous medium are investigated. A comparative analysis is executed for both isothermal and ramped conditions. The set of transformed domain equations has been obtained using a closed form of the Laplace transform method with the help of the Heaviside step function. Graphical and tabular explanations are provided for the physical characteristics of several flow parameters affecting the problem. Graphs are generated using MATLAB computing software. Findings of the problem manifest that the diffusion-thermo parameter and the radiation absorption parameter intensify the velocity and fluid temperature in the entire fluid area. This augmentation is most prominent for copper nanoparticles. Concentration, temperature, and velocity profiles in the case of ramped conditions are less than in isothermal conditions. Furthermore, the ramped parameter amplifies the heat transfer rate while reversing the mass transfer rate. It is also established that the volume concentration of nanoparticles enhances the heat transfer rate. The present study is of great interest in numerous fields of industry and machine-building applications. [ABSTRACT FROM AUTHOR]

Quantum carbon dots (QCDs) were efficiently synthesized from post-extraction residues generated during nopal fabric production using a hydrothermal treatment. These QCDs were applied to nopal fabrics, enhancing their UV solar radiation absorption. The synthesized QCDs exhibited fluorescence emissions in the 200–300 nm range. An eco-friendly dispersion was created by incorporating QCDs into TiO2 for use in smart textiles, which underlines our commitment to maintaining a sustainable process. Bright and fluorescent patterns were successfully applied to commercial and nopal fabrics using a spray printing technique. Additionally, the QCDs demonstrated pH-sensitive color changes, paving the way for practical applications. This work represents an initial step towards a circular economy by utilizing residues from nopal fabric production to synthesize quantum dots, which may be employed in smart textiles applications with UV absorption capabilities. [ABSTRACT FROM AUTHOR]

The C−C coupling of methane (CH4) and carbon dioxide (CO2) to generate acetic acid (CH3COOH) represents a highly atom‐efficient chemical conversion, fostering the comprehensive utilization of greenhouse gases. However, the inherent thermodynamic stability and kinetic inertness of CH4 and CO2 present obstacles to achieving efficient and selective conversion at room temperature. Our study reveals that hydroxyl radicals (⋅OH) and hydrated electrons (eaq−) produced by water radiolysis can effectively activate CH4 and CO2, yielding methyl radicals (⋅CH3) and carbon dioxide radical anions(⋅CO2−) that facilitate the production of CH3COOH at ambient temperature. The introduction of radiation‐synthesized CuO‐anchored TiO2 bifunctional catalyst could further enhance reaction efficiency and selectivity remarkably by boosting radiation absorption and radical stability, resulting in a concentration of 7.1 mmol ⋅ L−1 of CH3COOH with near‐unity selectivity (>95 %). These findings offer valuable insights for catalyst design and implementation in radiation‐induced chemical conversion. [ABSTRACT FROM AUTHOR]

The C−C coupling of methane (CH4) and carbon dioxide (CO2) to generate acetic acid (CH3COOH) represents a highly atom‐efficient chemical conversion, fostering the comprehensive utilization of greenhouse gases. However, the inherent thermodynamic stability and kinetic inertness of CH4 and CO2 present obstacles to achieving efficient and selective conversion at room temperature. Our study reveals that hydroxyl radicals (⋅OH) and hydrated electrons (eaq−) produced by water radiolysis can effectively activate CH4 and CO2, yielding methyl radicals (⋅CH3) and carbon dioxide radical anions(⋅CO2−) that facilitate the production of CH3COOH at ambient temperature. The introduction of radiation‐synthesized CuO‐anchored TiO2 bifunctional catalyst could further enhance reaction efficiency and selectivity remarkably by boosting radiation absorption and radical stability, resulting in a concentration of 7.1 mmol ⋅ L−1 of CH3COOH with near‐unity selectivity (>95 %). These findings offer valuable insights for catalyst design and implementation in radiation‐induced chemical conversion. [ABSTRACT FROM AUTHOR]

The C−C coupling of methane (CH4) and carbon dioxide (CO2) to generate acetic acid (CH3COOH) represents a highly atom‐efficient chemical conversion, fostering the comprehensive utilization of greenhouse gases. However, the inherent thermodynamic stability and kinetic inertness of CH4 and CO2 present obstacles to achieving efficient and selective conversion at room temperature. Our study reveals that hydroxyl radicals (⋅OH) and hydrated electrons (eaq−) produced by water radiolysis can effectively activate CH4 and CO2, yielding methyl radicals (⋅CH3) and carbon dioxide radical anions(⋅CO2−) that facilitate the production of CH3COOH at ambient temperature. The introduction of radiation‐synthesized CuO‐anchored TiO2 bifunctional catalyst could further enhance reaction efficiency and selectivity remarkably by boosting radiation absorption and radical stability, resulting in a concentration of 7.1 mmol ⋅ L−1 of CH3COOH with near‐unity selectivity (>95 %). These findings offer valuable insights for catalyst design and implementation in radiation‐induced chemical conversion. [ABSTRACT FROM AUTHOR]

The C−C coupling of methane (CH4) and carbon dioxide (CO2) to generate acetic acid (CH3COOH) represents a highly atom‐efficient chemical conversion, fostering the comprehensive utilization of greenhouse gases. However, the inherent thermodynamic stability and kinetic inertness of CH4 and CO2 present obstacles to achieving efficient and selective conversion at room temperature. Our study reveals that hydroxyl radicals (⋅OH) and hydrated electrons (eaq−) produced by water radiolysis can effectively activate CH4 and CO2, yielding methyl radicals (⋅CH3) and carbon dioxide radical anions(⋅CO2−) that facilitate the production of CH3COOH at ambient temperature. The introduction of radiation‐synthesized CuO‐anchored TiO2 bifunctional catalyst could further enhance reaction efficiency and selectivity remarkably by boosting radiation absorption and radical stability, resulting in a concentration of 7.1 mmol ⋅ L−1 of CH3COOH with near‐unity selectivity (>95 %). These findings offer valuable insights for catalyst design and implementation in radiation‐induced chemical conversion. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis and characterization of 2D polygonic ZnO microplatelets for application as UV filters in sunscreens. ZnO microplatelets are obtained via a simple method involving chemical precipitation, aging, and calcination. XRD, SEM, and TEM analyses confirm the successful formation of ZnO microplatelets. DRUV‐Vis studies indicate that the ZnO microplatelets have a band gap energy value of 3.2 eV and exhibit good UV radiation absorption, similar to a commercial ZnO reference sample. Furthermore, in methylene blue photodegradation studies, the ZnO microplatelets show significantly lower photocatalytic activity than the ZnO reference sample. Under UV irradiation of 254 nm and 365 nm wavelengths, the dye in contact with ZnO microplatelets is photodegraded by only 38 % and 69 % after 5 h, compared to the reference sample, which photodegraded the dye by 87 % and 97 %, respectively. The performance of a sunscreen formulation containing the ZnO microplatelets (at 10 wt %), in terms of the photoprotection factors and photostability, is on par with that of a formulation containing the ZnO reference sample. Due to their microplatelet structure, good UVR absorption capacity, and relatively lower photocatalytic activity, the ZnO microplatelets show potential for application as UV filters in sunscreen products. [ABSTRACT FROM AUTHOR]

The purpose of this study is to understand a physical mechanism to determine the surface temperature of clothes in calm and fine conditions of outdoors. We observed surface temperatures of polo shirts of the same material and design but different colors. The shirts were placed in unshaded and well-ventilated outdoor, open spaces on sunny summer days. The maximum difference between dark green or black and white was more than 15 °C during calm, fine weather and was greatest when the solar radiation was strong. If the transmission of solar radiation energy through a shirt is ignored to calculate the absorption by the shirt, the difference in solar radiation absorption due to different colors is as much as 24% in the maximum, and if considered, we concluded that an absorption difference of 34% led to a temperature difference of 15℃. When we compared the brightness of the colors, we found that the albedo of both the visible and NIR bands explained why the red and green colors were so different with respect to the surface temperatures we observed. The reflection in the NIR bands was also an important determinant of the surface temperature. An additional experiment using masks showed that the temperature difference between white and black was almost eliminated at a wind speed of ~ 3 m/s. The color of clothing is therefore a target for small-scale adaptation to climate change. [ABSTRACT FROM AUTHOR]

Context: The coat is the first defense layer protecting animals from direct sunlight, influencing radiant-heat absorption and loss. Dark coat colour may increase animal heat impact because of higher absorption of solar radiation. Aims: We investigated the impact of pigmentation intensity on the heads of animals and their thermal responses to solar radiation. Furthermore, we compared the thermal responses between dark and light brown-coloured animals, to determine whether the duration of sun and shade exposure (3 h each) is sufficient to differentiate the heat gain and losses between the two groups. Methods: The effect of coat colour on rectal and surface temperatures in Boer goats, classified according to their head pigmentation pattern as dark (DB, N = 11) or light brown (LB, N = 11), exposed to sun and shade, was evaluated. The animals' body and head surface temperatures were measured the same day before, during, and after sun exposure by using infrared thermography. Individual thermographic images were analysed by body regions (rump, leg, neck) and head areas (eye, ear, upper and lower part of the head, and the muzzle). Key results: During solar radiation, all measured variables increased. In the shade, the rump, leg, and neck surfaces remained elevated, whereas the head area cooled down faster, with the highest temperature changes measured for the ear of about 10%. Most surface cooling occurred within 30 min after returning to the shade. Coat colour groups differed only in higher overall muzzle temperature of DB than that of LB goats (P = 0.048). Correlations between rectal and surface temperatures were low to medium, ranging from −0.02 (eye) to 0.31 (muzzle). Conclusions: The head area is suggested as the important thermal window for heat dissipation and selective brain cooling. Light brown-headed animals were more efficient in eliminating the heat gained from solar radiation when returned to shade. Implications: The colouration of the animal's head may play an important role for its heat tolerance. As an easy-to-recognise characteristic, coat colour can serve as a selection trait for local goat populations. In view of global warming, selection for lighter coat colour in domestic ruminants may also become important even under temperate climates. Coat colour plays an important role in heat tolerance of livestock, because dark coat colour may increase animal heat stress as a result of higher absorption of solar radiation. We focused on the influence of head pigmentation of Boer goats and found light brown-headed animals to be more efficient in eliminating the solar heat gained during outdoor grazing when returned to the shade. In view of global warming, breeding for light coat colour in domestic ruminants could alleviate heat stress. [ABSTRACT FROM AUTHOR]

This paper proposes a 10 × 10 MIMO multiband broadband planar antenna for tablets or laptops. The designed antennas cover a large number of the popular sub‐6‐GHz application bands, such as 0.617–0.96, 2.1–2.7, 3.5–4.5, and 6.1–7.2 GHz for public safety communications, radio systems, Bluetooth, Wi‐Fi, and satellite communications. The proposed antenna is designed with grounded branches, which can generate a wide bandwidth and cover most of the sub‐6‐GHz application band by coupling between branches of different lengths and antennas. MIMO antennas have been measured to have an envelope correlation coefficient of less than 0.7 and have met the standards set by international organizations for human radiation absorption simulations. The proposed antenna validates the unique 10 × 10 MIMO antenna structure and feasibility. Multiple operable frequency bands are realized, and the radiation effect of the antenna on the human body is analyzed if it complies with international market standards. The proposed antenna design is well suited for multiband and broadband requirements. [ABSTRACT FROM AUTHOR]

Deep geothermal drilling is a necessary technological stage to produce renewable energy by "enhanced geothermal systems" everywhere. However, the high cost and complexity of deep drilling through hard rock formations is a major barrier to its commercialization. One approach to reach affordability and reduce the cost of deep drilling is to use millimeter-wave (mmw) gyrotron radiation to melt or vaporize rocks. In this paper, the results of an experimental study of mmw radiation absorption by hard rocks are presented. Electromagnetic attenuation and reflection were measured in W-band at frequencies from 75 to 110 GHz in eight rock samples from six different geological formations originated in Israel. The results show that the mmw radiation absorption in hard rocks ranges from 90 to 99% per centimeter. The absorption varies slightly with rock type and is relatively independent of frequency but has reached higher values at the upper W band for all samples. The study suggests that high-power mmw radiation is a promising technology for deep geothermal drilling. The results of this experiment, attenuation, and reflection of W-band radiation in hard rocks provide valuable information for the design and optimization of mmw-based drilling systems, and will support the design and optimization of gyrotron based hard rock drilling equipment for geothermal applications. [ABSTRACT FROM AUTHOR]

Biomass burning emits large numbers of organic aerosol particles, a subset of which are called tarballs (TBs). TBs possess a spherical morphology and unique physical, chemical, and optical properties. They are recognized as brown-carbon aerosol particles, influencing the climate through the absorption of solar radiation. Aerosol particles were collected from wildfire and agricultural-fire smoke sampled by NASA's DC-8 aircraft during the Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign in the western US from July to September 2019. This study developed an image analysis method using deep learning to distinguish TBs from other round particles that deformed on the substrate, based on the particles' morphological characteristics in transmission electron microscopy images. This study detected 4567 TBs, with most occurring < 10 h downwind of the emissions, and measured their compositions, abundance, sizes, and mixing states. The number fraction, mass fraction, and concentration of TBs in wildfire smoke corresponded to 10 ± 1 %, 10 ± 2 %, and 10.1 ± 4.6 µgm-3 , respectively. As the smoke aged for up to 5 h after emission, the TB number fractions roughly increased from 5 % to 15 %, indicating that TBs are processed primary particles. We also observed TBs associated with pyrocumulonimbus (pyroCb) activity and various TB mixing states. This study reveals the abundance, as well as the physical and chemical properties, of a wide range of TBs from various biomass-burning events and enhances our knowledge of TB emissions, contributing to the evaluation of the climate impact of TBs. [ABSTRACT FROM AUTHOR]

This study is aimed at fabricating composite films by cross‐linking polyvinyl alcohol (PVA) and dialdehyde cellulose (DAC) in varying ratios using citric acid as a catalyst. The acetal formation between the two components was studied using FTIR. Characterizations of the physiochemical properties revealed that increasing the DAC ratio of the composite film improved the hydrophobicity, tensile strength and barrier properties (water vapour, UV and oxygen) of the films while reducing elongation at break (flexibility), swelling and solubility of the film in water. When the DAC ratio was elevated to 50%, the tensile strength was enhanced to 98 MPa. In comparison, flexibility diminished to 29%, the solubility of the film reduced to 10% and water vapour permeability was lower by two orders of magnitude than that of the control PVA film. The peroxide value of linoleic acid decreased from 21.2% ± 7.6 (packed with PVA film) to 9.9% ± 0.9 (packed with 50% DAC composite film) after 15 days. Furthermore, the composite films demonstrated effective absorption of UV radiation, with the order of effectiveness being UV‐C > UV‐B > UV‐A radiation. No significant difference in biodegradability was detected in the composite films with an increase in DAC ratio during indoor soil burial tests for 30 days. This study implies that the composite film could serve as an alternative sustainable packaging option, especially when transparency and high oxygen barrier properties are desired. [ABSTRACT FROM AUTHOR]

Due to the long‐range atomic disorder and more active sites, amorphous MXenes with better chemical reactivity and electrical conductivity, have attracted wide attention in energy storage devices. However, to reach the practical applications of MXenes, investigations into the best structure of the amorphous layer are essential. Here, the structure evolution of MXenes induced from ammonium persulfate is explored via synchrotron radiation X‐ray absorption spectroscopy. Then, a kind of oxygen‐poor amorphous heterojunction Nb2CTx MXene (a‐Nb2CTx) is designed. Benefitting from the oxygen‐poor amorphous heterojunction, the a‐Nb2CTx electrode exhibits excellent Li+ storage performance with a high discharge specific capacity of 382 mAh g−1 at 0.1 A g−1 and a long cycling stability of 300 mAh g−1 at 1.0 A g−1 after 800 cycles. Operando synchrotron X‐ray diffraction results reveal that oxygen‐poor amorphous heterojunction stabilizes Nb2CTx MXene from undergoing structural changes during cycling. This work provides new insights into the rational design of novel amorphous MXenes, which is of great significance for the development of MXenes and their applications in high‐performance energy storage systems. [ABSTRACT FROM AUTHOR]

To study non-traditional glass materials, this investigation created four glass samples composed of (70-x)B 2 O 3 –20TeO 2 -10GeO 2 -xMgO, where x represents the percentage of MgO with values of 20, 25, 30, and 35 mol%. Glasses with high transparency were produced via the accepted melt quenching and annealing method. The samples underwent X-ray diffraction analysis to confirm their glassy structure. Fourier transform infrared spectroscopy was utilized to examine the glass network's various structural groups. The measuring methodology and theoretical calculations were used to calculate a range of physical and mechanical parameters. The cut-off wavelength, as well as the direct and indirect bandgap, and other optical characteristics of the S1–S4 samples were observed using optical absorption. The work utilized Phy-X to acquire the ionizing absorption parameters. The paper demonstrates various glasses' radiation shielding properties, including the effective atomic number, half- and tenth-value layers, linear attenuation coefficient, mass attenuation coefficient, and mean free path. [ABSTRACT FROM AUTHOR]

This study investigates the mass and heat transfer properties of Ag-H2O nanofluid MHD Forchheimer flows and Ag-MoS2/H2O hybrid nanofluid over two-dimensional linear stretching surfaces in aligned magnetic fields with absorption of radiation. The fluid experiences rotational motion around the vertical axis at a consistent angular speed. The system of nonlinear ODEs is derived from the set of nonlinear PDEs by use of similarity transformations. The BVP-5C shooting approach in MATLAB is then employed to solve the associated system of ODEs. As the Forchheimer number, porosity parameter, rotation parameter and aligned magnetic field exhibit an ascent, the velocity profile along the x-axis and y-axis experiences a decrement. Simultaneously, an augmentation in the magnetic parameter, thermal radiation and rotation parameter induces a heightened temperature profile. Additionally, greater values of the Forchheimer number, rotation parameter and magnetic parameters correspond to an increase in concentration profile. Furthermore, the results indicated an increased temperature profile in the Ag-MoS2/H2O hybrid nanofluid compared to that in the Ag-H2O nanofluid for magnetic, rotation and radiation parameters. Also, the concentration profile of magnetic and rotation parameters along with the Forchheimer number were noted to be higher in the Ag-MoS2/H2O hybrid nanofluid compared to that in the Ag-H2O nanofluid. [ABSTRACT FROM AUTHOR]

The structure of sound waves in baryonic gas generated during the evolution of spherically symmetric dark matter halos with a mass less than the Jeans mass has been calculated. In this case, the source of the gravitational field that creates the wave can be at both the linear stage (evolving perturbation in dark matter) and the nonlinear stage (separated and virialized object). Peculiar motions of baryons in a sound wave in the second order in speed cause the absorption of relict radiation in the 21 cm line. It is shown that this additional absorption on sound waves is a fraction of a percent at redshifts of the absorption value in the model of a homogeneous Universe, however, the additional absorption can be larger in the case of a non-standard spectrum of cosmological perturbations of matter density on small scales. [ABSTRACT FROM AUTHOR]

In the composition range of x= 0-5 mol%, glasses in the system 60SiO2-35Pb3O4-(5-) ZnO-xMoO3 have been investigated. An amorphous network structure characterizes the glasses. The density values for the LZSM glasses scaled between 5.91 g/cm for Mo0 and 6.249 g/cm for Mo5. The ultrasonic technique indicates that the shear and longitudinal speeds (VT & VL) increase linearly as the amount of MoO3 substituted for ZnO in the fabricated glasses increases. The elastic moduli were calculated and found to be increased with an increase in both ultrasonic velocities and density of the glass, which suggests a correlation between these parameters in the fabricated glasses. The radiation attenuation capacity with the addition of MoO3 increased systematically, which indicates the role of MoO3 in modifying the glass composition and enhances its ability to attenuate against harmful radiation. Mo5 establishes excellent protective resources compared to other substances, so Mo5 develops a favorable selection for building radiation absorption blocks. Such blocks show an acute character in protecting both nature and a person's health versus the dangerous impacts of radiation exposure. [ABSTRACT FROM AUTHOR]

The influence of interatomic collisions in a gaseous medium on intra-Doppler resonances of absorption of optical radiation in a thin gas cell was theoretically studied and could be recorded by recently developed laser spectroscopy methods. The limitations on the pressure of the gaseous medium at which the influence of such collisions on the width of these resonances was insignificant were determined. The results could find application in ultra-high resolution atomic spectroscopy and in compact optical frequency standards based on the thin gas cells under consideration. [ABSTRACT FROM AUTHOR]

The present investigation was performed to figure out the chemical constituents and biological potential of polar extracts (AcOEt and BuOH) from Achillea ligustica, a medicinal species of the Asteraceae family. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) was utilized to conduct a preliminary analysis of the phytochemical profiles of the AcOEt and BuOH extracts. The analysis revealed the existence of twenty compounds in the AcOEt extract and twenty-two in the BuOH extract, classified into various types of secondary metabolites. Subsequently, the exudate from the plant yielded five flavonoids, including two 6-methoxyflavonols identified for the first time in this genus. The isolation of compounds from AcOEt and BuOH extracts was achieved through the combined use of column chromatography (silica gel and Sephadex LH-20) and preparative TLC chromatography. The structures have been elucidated using 1D and 2D NMR spectroscopy, alongside comparisons with research data. Our study measured the total phenolic and flavonoid contents and carried out a comprehensive range of antioxidant tests using DPPH, GOR, CUPRAC, reducing power, and O-phenanthroline assays. Both extracts exhibited considerable antioxidant potential and contained high levels of phenolic and flavonoid compounds. The photoprotective effect of the AcOEt and BuOH extracts was evaluated in vitro by measuring the sun protection factor. Both extracts exhibited a high capacity for UV radiation absorption. Consequently, this plant presents an intriguing prospect for future research focused on incorporating it into photoprotective cosmetic products and pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

Within the field of radiology, safeguarding against radiation is crucial, particularly in diagnostic procedures like X-rays, as radiation exposure holds the potential to harm cellular DNA. Presently, lead serves as the predominant material for radiation shielding. However, its usage raises environmental concerns owing to its toxic properties. The objective of this study is to investigate a radiation shielding alternative to lead and assess its efficacy in protecting against radiation. We examined the radiation absorption properties of material made from a composite of PBS and iodine contrast media in various proportions. Our findings indicate that the shielding material containing 75% iodine have the greatest ability to reduce radiation dose from X-rays but are still less than lead. Moreover, the PBS composite with iodine contrast media proved to be environmentally friendly, flexible, and exhibited excellent shielding performance in mitigating exposure during diagnostic X-ray procedures. [ABSTRACT FROM AUTHOR]

Heat absorption and thermal radiation have significant roles in engineering and research. These two principles have applications in thermal transportation, gas turbines, nuclear power plants, electrical fuel, aerospace engineering, projectiles and renewable energy. The present work analyses the stagnation point ternary nanofluid motion over a circulating sphere in the presence of a magnetic field and radiation absorption. The nonlinear controlling equations are replaced by ordinary differential equations by applying a suitable comparison factor. The bvp4c process was used to establish numerical outcomes of the partial differential equations. This mathematical numerical findings are presented graphically. The results of ternary nanoparticles (Cu–Ag–CuO/water), hybrid nanoparticles (Cu–Ag/water) and copper (Cu) nanoparticles have also been compared, and this comparison suggests that ternary nanoparticles (Cu–Ag–CuO/water) are more effective at attenuating hemodynamic factors (such as wall shear stress and heat transfer) than hybrid and copper (Cu) nanoparticles. Comparison with previous literature results is also done and the results are found to be in very good agreement with those published earlier. [ABSTRACT FROM AUTHOR]

The current work is interested on investigating the impacts of thermal radiation, chemical reaction, and absorption radiation of a hydromagnetic convection‐free mass and heat transfer flow in case of an electrically conducting fluid that passes through a vertical plate moving impulsively. The analytical solutions of the governing momentum, energy, and species concentration equations with the initial and boundary conditions are obtained by the Laplace transformation technique. Graphs for fluid characteristics are used to analyze the impact of changing parametric quantities such as M, N, Sc, Kc, Q, Gr, Gm, and t on the temperature, velocity, concentration, and Sherwood number. We derive the engineering curiosity expressions for the Nusselt number and stress, and at the end, we tabulate and discuss the consequences of new parameters. The magnetic field effect and the chemical reaction are seen to diminish the fluid velocity and concentration, respectively, but in contrast, the absorption radiation effect is seen to accelerate both velocity and temperature. It is closely studied that the Nusselt number and skin friction values for hydrogen consistently exceed those for carbon monoxide. [ABSTRACT FROM AUTHOR]

This manuscript introduces a radical solution for early prediction of patient's bone health, employing a simply devised Hexagonal Ring Wearable Textile Antenna (HRWTA) exploiting the electromagnetic band gap (EBG) structures for Low Specific Absorption Rate (SAR). It is constructed using low loss woven polyester fabric as substrate and integrates conductive electro-textile fabric as a radiating unit. It has an on-body simulated and measured impedance (VSWR ≤ 2) bandwidth (BW) of 350 MHz (3.39-3.74 GHz, 10%) and 320 MHz (3.35-3.67 GHz, 9.2 %) without EBG respectively. HRWTA with EBG has bandwidth of 190 MHz (3.38-3.57 GHz, 5.4%) and 180 MHz (4.16-4.34GHz, 5.14%). The measured results are in good agreement with simulated. The shift in resonant frequency has been noticed for HRWTA #1 (2.45 GHz) and HRWTA#2 (4.2 GHz) while HRWTA#3 resonates at 3.5 GHz. This is due to fabrication tolerance and dielectric variation of fabrics due to trapped air bubble. Hence, HRWTA 3 is constructed with more precision which resonates at 3.5 GHz. It has a peak gain of 2.5 dB at 3.5 GHz and gain variation over the band is within 1 dB. By exploiting an EBG structure, electromagnetic radiation absorption is minimized and SAR obtained is within the allowable range ensuring safer interaction with the human body. HRWTA exhibits decent radiation characteristics, ample gain and agreeable act under bended condition makes it fit for wearable applications. HRWTA covers 3.4 GHz to 3.6 GHz band which holds specific significance in medical field for bone density measurement (BDM). [ABSTRACT FROM AUTHOR]

Germanium (Ge) is a system-forming material of IR photonics for the atmospheric transparency window of 8–14 µm. For optics of the 3–5 µm range, more widespread silicon (Si), which has phonon absorption bands in the long-wave region, is predominantly used. A technology for growing Ge single crystals has been developed, allowing the production of precision optical parts up to 500 mm in diameter. Ge is used primarily for the production of transparent optical parts for thermal imaging devices in the 8–14 µm range. In addition, germanium components are widely used in a large number of optical devices where such properties as mechanical strength, good thermal properties, and climatic resistance are required. A very important area of application of germanium is nonlinear optics, primarily acousto-optics. The influence of doping impurities and temperature on the absorption of IR radiation in germanium is considered in detail. The properties of germanium photodetectors are reported, primarily on the effect of photon drag of holes. Optical properties in the THz range are considered. The features of optical properties for all five stable isotopes of germanium are studied. The isotopic shift of absorption bands in the IR region, caused by phonon phenomena, which was discovered by the authors for the first time, is considered. [ABSTRACT FROM AUTHOR]

The current investigation aims at to examine the effect of radiation absorption, heat generation and Dufour number on MHD Casson fluid flow past an exponentially accelerated vertical plate in a porous medium with chemical reaction. The governing equations for momentum, energy and concentration are solved by implementing the Laplace transformation method. Skin friction, rate of heat transfer and rate of mass transfer expressions are also extracted and depicted in tabular form. Investigation simulates that Casson parameter diminished the fluid velocity, whereas energy flux due to a mass concentration gradient improves the temperature field of the flow problem. In addition to this, temperature field is observed to be developed under the influence of radiation absorption and heat generation. Furthermore, the effects of different non-dimensional parameters on velocity field, temperature fluid and species concentration are exhibited graphically.

We study the Helmholtz equation with periodic coefficients in a closed waveguide. A functional analytic approach is used to formulate and solve the radiation problem in a self‐contained exposition. In this context, we simplify the non‐degeneracy assumption on the frequency. Limiting absorption principles (LAPs) are studied, and the radiation condition corresponding to the chosen LAP is derived; we include an example to show different LAPs lead, in general, to different solutions of the radiation problem. Finally, we characterize the set of all bounded solutions to the homogeneous problem. [ABSTRACT FROM AUTHOR]

In the existence of Joule heating and thermal radiation, we researched the Hall current and Radiation absorption consequences of MHD mixed convective movement of an indestructible and electrically operating viscous liquid moving via an endless upright permeable plate. This flow was seen to be occurring in the presence of thermal radiation. The perturbation approach is employed to find a solution for the non-dimensional equations. Within the boundary layer, we investigate the impact of the different non-dimensional factors on the velocities, temperatures, and concentrations of the fluid. Furthermore, computational debates or discussions are also conducted regarding the effects of pertinent factors on the shear stress rate and the rate of heat and mass transfer. The fluid velocity and temperature enhance with increasing Hall and Radiation absorption parameters, and temperature tends to diminish as the thermal radiation increases. Increases in the permeability factor reduce the skin friction coefficient. Still, increases in the thermal and mass Grashof numbers have the opposite effect—the rise in the Prandtl number results in an increase in the Nusselt number. Sherwood number decreases as the amount of radiation that is absorbed increases. [ABSTRACT FROM AUTHOR]

Introduction: The emergence of electromagnetic wave pollution as a new form of pollution in human society is attributed to the advancements in communication technology and the electronic information business. In addition to harming priceless electronic equipment, these electromagnetic radiation and interference issues brought on by electrical and electronic devices have a major negative influence on human productivity and wellbeing. The secret to getting rid of electromagnetic radiation interference (EMI) and improving performance is electromagnetic shielding technology. Metamaterial absorber is a type of metamaterial that absorb EMI radiation. The benefits of metamaterial absorbers include their lightweight, simple construction, and excellent absorptivity. Methods: This paper proposes a novel metamaterial absorber for EMI radiation absorption. It consists of dielectric layers, metamaterial shielding layer and transmission line. The reflection of radiation is reduced by miniaturization of metamaterials. Results and Discussion: Simulation results show that the proposed design has better performance as compared to existing methods. The operating frequency range is from 23.1 to 28.3 GHz. The values of S21 with and without shielding are -5 dB and -0.05 dB, and the shielding effectiveness is 10.10 dB and a maximum of 12.63 dB. [ABSTRACT FROM AUTHOR]

IR light-emitting diodes (LEDs) based on InGaAs/AlGaAs multiple quantum wells (MQWs) and AlxGa AsyP layers, compensating stress in the active area, have been developed. The optical losses caused by absorption of the radiation generated by the active area (λ = 940 nm) have been investigated at different doping levels of n-GaAs substrates. It is shown that reduction of the donor doping level from 4 × 1018 to 5 × 1017 cm–3 gives an increase in the LED quantum efficiency of ~30%. A technology making it possible type to eliminate completely the optical losses caused by absorption during radiation output has been developed. Removal of the substrate and transfer of the device structure to a carrier substrate with formation of a rear metal reflector made it possible to create LEDs demonstrating a twofold increase in the external quantum efficiency (EQE) and efficiency (~40%) as compared to the technology of radiation output through an n-GaAs substrate. [ABSTRACT FROM AUTHOR]

Using the results on the structural changes of cured carbon-, glass-, and organic plastics subjected a microvave electromagnetic field, by the method of low-coherence reflexometry, it is found out that the radiation intensity absorbed by the material decreases on average by 15%, 9,4% and 8,4%, respectively, which is indicated by the increased material structure density. It is argued that the influence of the microwave treatment on the filler-free binder is insignificant. The results obtianed objectively indicate a decrease in the number of defects (cracks, delaminations, pores, etc.) and a respective increase of the structure density of cured polymer composite materials processed with microwave electromagneticfield radiation. [ABSTRACT FROM AUTHOR]

Invasive species have historically disrupted environments by outcompeting, displacing, and extirpating native species, resulting in significant environmental and economic damage. Developing approaches to detect the presence of invasive species, favorable habitats for their establishment, and predicting their potential spread are underutilized management strategies to effectively protect the environment and the economy. Spotted lanternfly (SLF, Lycorma delicatula) is a phloem-feeding planthopper native to China that poses a severe threat to horticultural and forest products in the United States. Tools are being developed to contain the spread and damage caused by SLF; however, methods to rapidly detect novel infestations or low-density populations are lacking. Vegetation spectroscopy is an approach that can represent vegetation health through changes in the reflectance and absorption of radiation based on plant physiochemical status. Here, we hypothesize that SLF infestations change the spectral and chemical characteristics of tree canopies. To test this hypothesis, we used a full range spectroradiometer to sample canopy foliage of silver maple (Acer saccharinum) and red maple (Acer rubrum) trees in a common garden in Berks County, Pennsylvania that were exposed to varying levels of SLF infestation. Foliar spectral profiles separated between SLF infestation levels, and the magnitude of separation was greater for the zero-SLF control compared with higher infestation levels. We found the red-edge and portions of the NIR and SWIR regions were most strongly related to SLF infestation densities and that corresponding changes in vegetation indexes related to levels of chlorophyll were influenced by SLF infestations, although we found no change in foliar levels of chlorophyll. We found no influence of SLF densities on levels of primary metabolites (i.e., pigments, nonstructural carbohydrates, carbon, and nitrogen), but did find an increase in the phenolic compound ferulic acid in response to increasing SLF infestations; this response was only in red maple, suggesting a possible species-specific response related to SLF feeding. By identifying changes in spectral and chemical properties of canopy leaves in response to SLF infestation, we can link them together to potentially better understand how trees respond to SLF feeding pressure and more rapidly identify SLF infestations. [ABSTRACT FROM AUTHOR]

Earth went through at least two periods of global glaciation (i.e., "Snowball Earth" states) during the Neoproterozoic, the shortest of which (the Marinoan) may not have lasted sufficiently long for its termination to be explained by the gradual volcanic build‐up of greenhouse gases in the atmosphere. Large asteroid impacts and supervolcanic eruptions have been suggested as stochastic geological events that could cause a sudden end to global glaciation via a runaway melting process. Here, we employ an energy balance climate model to simulate the evolution of Snowball Earth's surface temperature after such events. We find that even a large impactor (diameters of d ∼ 100 km) and the supervolcanic Toba eruption (74 Kyr ago), are insufficient to terminate a Snowball state unless background CO2 has already been driven to high levels by long‐term outgassing. We suggest, according to our modeling framework, that Earth's Snowball states would have been resilient to termination by stochastic events. Plain Language Summary: The terminations of Earth's longest periods of global glaciation are commonly understood to have occurred due to the gradual build‐up of greenhouse gases in the atmosphere from volcanism. However, the sudden ends of Earth's shorter global glaciation periods likely cannot be explained by the same mechanisms. Large asteroid impacts and supervolcanic eruptions have been suggested as geophysical phenomena that could cause abrupt ends to global glaciation periods. Here, we model the evolution of the planet's surface temperature in the aftermath of such events. Impacts and eruptions open up gaps in the global ice sheet, and also partially cover the ice in far‐spreading dust and ash, both of which increase the amount of solar radiation that is absorbed by the planet comparing to the highly reflective surface of ice and snow. Greater absorption of radiation leads to higher surface temperatures, which increases ice melting, and generates a feedback loop that can melt the entire planet surface. However, we find that the scales of impact or eruption required to produce global melting are too great to have likely occurred at the times of Earth's global glaciations. Other mechanisms must, therefore, be explored to explain Earth's short glaciation periods. Key Points: We use an Energy Balance Model (EBM) to simulate the response of Snowball climate after stochastic eventsImpact simulations and estimates of ash dispersion are used to inform initial conditionsEarth's Snowball states seem resilient to termination by stochastic events within our modeling framework [ABSTRACT FROM AUTHOR]

Black carbon in snow (BCS) is a crucial parameter in Earth System modeling, as it influences global radiative balance. Here, simulated BCS from Coupled Model Intercomparison Project Phase 5 and 6 (CMIP5 and CMIP6) that provided BCS as a model output were evaluated. In comparison with global BCS observations, CMIP5/6 models successfully reproduced long‐term historical trends linked to human activities, but struggled capturing decadal variability caused by natural climate variability. CMIP6 models NorESM2‐MM, NorESM2‐LM, and TaiESM1 yielded the most accurate simulations of BCS concentration with modest overestimation of <50%, while the four CESM2 models underestimated concentrations by up to ∼80%. These errors effectively balanced for the CMIP6 multi‐model ensemble mean (MME), which had a relative error (RE) of −37%. However, the CMIP5 MME was less reliable due to extreme overestimation by up to 8,000% in the three MIROC models. The significant BCS concentration errors in the MIROC and CESM2 models were linked mainly to errors in handling of BC in snow processes. Conversely, marked improvements in NorESM, the only common to both CMIP5 and CMIP6, were due to improved simulation of black carbon deposition. BCS errors significantly impacted radiative forcing estimates, particularly at the poles, where model errors reached several thousandfold. CMIP6 exhibited superior results compared to CMIP5, achieving global MME RE of −33% in radiative forcing estimates. However, it's worth noting BCS output is currently limited, with only seven models available for each of CMIP5 and CMIP6 here. Additional models simulating BCS are desirable in the next CMIP generations. Plain Language Summary: Black carbon in snow (BCS) has important implications for snow albedo reduction, solar radiation absorption, and snow melt acceleration on the Earth. However, model performance in BCS simulation remains unclear in the widely used Coupled Model Intercomparison Project phases 5 and 6 (CMIP5/6). In this study, CMIP5 and CMIP6 models providing BCS information were evaluated against a global data set of BCS observations from ice cores and snow samples. Results indicate that both CMIP generations successfully reproduce long‐term trends in BCS but fail to capture the decadal variability. Marked differences exist in modeled BCS concentrations, with the best‐performing models (NorESM2‐LM, NorESM2‐MM, and TaiESM1) overestimating concentrations by <50%, while the three worst‐performing MIROC models yield extreme overestimation. Such discrepancies stem primarily from the post‐depositional treatment of black carbon in snow, which influences the estimation of climate‐warming effects of BCS. Key Points: The global pattern of black carbon in snow (BCS) is effectively simulated by CMIP5/6 models, but large errors remainPost‐depositional snow processes contribute most to the large simulated‐BCS errorsBCS‐induced radiative forcing in Antarctica is poorly simulated by CMIP5/6 models with an overestimation of ∼200,000% and 144%, respectively [ABSTRACT FROM AUTHOR]

An investigation of the impacts of magnetic field, heat generation/absorption and thermal radiation on unsteady free convection dusty fluid flow over a non-isothermal vertical cone enclosed inside a porous medium is explored. The Crank–Nicolson approach is used to get the numerical solutions for these nonlinear, coupled partial differential equations (PDEs). The interaction of physical parameter range on temperature and velocity distribution is calculated and graphically presented. The results demonstrate that when the porosity, heat generation/absorption, and thermal radiation parameters are increased, the velocities rise, whereas the magnetic and mass concentration of particle phase parameters have an opposite effect. Furthermore, raising the fluid-particle interaction parameter causes a rise in dust phase velocity but a reduction in fluid phase velocity. [ABSTRACT FROM AUTHOR]

An electrically conducting time-dependent flow of water-based nanofluid comprised of Copper and Titanium oxide over a stationary plate embedding with a porous matrix is analyzed in this study. The novelty arises due to the interaction of both the thermal radiation as well as the radiation absorption that affect the heat transport phenomenon. In the single-phase flow, both the variation of particle concentration and the solutal concentration for the inclusion of chemical reaction are taken care of. Also, the influence of the free convection phenomena is explained significantly. The transformed dimensionless system of the governing equations is handled analytically by using the Laplace Transform method. The behavior of the characterizing parameters involved in the governing equations is presented via graphs and the simulation of the numerical results of the rate coefficients like shear rate and rate of heat and solutal transfer is deployed through the table. However, the physical significance of these parameters is deliberated briefly. Finally, the important outcomes are higher heavier species because of lesser solutal diffusivity which attenuates the fluid concentration throughout the domain. Further, radiation absorption causes a significant boost in the nanofluid temperature distribution. [ABSTRACT FROM AUTHOR]

Data from the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS) instruments onboard the Landsat 8 and Landsat 9 satellite platforms are subject to contamination by cloud cover, with cirrus contributions being the most difficult to detect and mask. To help address this issue, a cirrus detection channel (Band 9) centered within the 1.375-μm water vapor absorption region was implemented on OLI, with a spatial resolution of 30 m. However, this band has not yet been fully utilized in the Collection 2 Landsat 8/9 Level 2 surface temperature data products that are publicly released by U.S. Geological Survey (USGS). The temperature products are generated with a single-channel algorithm. During the surface temperature retrievals, the effects of absorption of infrared radiation originating from the warmer earth's surfaces by ice clouds, typically located in the upper portion of the troposphere and re-emitting at much lower temperatures (approximately 220 K), are not taken into consideration. Through an analysis of sample Level 1 TOA and Level 2 surface data products, we have found that thin cirrus cloud features present in the Level 1 1.375-μm band images are directly propagated down to the Level 2 surface data products. The surface temperature errors resulting from thin cirrus contamination can be 10 K or larger. Previously, we reported an empirical and effective technique for removing thin cirrus scattering effects in OLI images, making use of the correlations between the 1.375-μm band image and images of any other OLI bands located in the 0.4–2.5 μm solar spectral region. In this article, we describe a variation of this technique that can be applied to the thermal bands, using the correlations between the Level 1 1.375-μm band image and the 11-μm BT image for the effective removal of thin cirrus absorption effects. Our results from three data sets acquired over spatially uniform water surfaces and over non-uniform land/water boundary areas suggest that if the cirrus-removed TOA 11-μm band BT images are used for the retrieval of the Level 2 surface temperature (ST) data products, the errors resulting from thin cirrus contaminations in the products can be reduced to about 1 K for spatially diffused cirrus scenes. [ABSTRACT FROM AUTHOR]

Volcanic aerosols reduce global mean precipitation in the years after major eruptions, yet the mechanisms that produce this response have not been rigorously identified. Volcanic aerosols alter the atmosphere's energy balance, with precipitation changes being one pathway by which the atmosphere acts to return toward equilibrium. By examining the atmosphere's energy budget in climate model simulations using radiative kernels, we explain the global precipitation reduction as largely a consequence of Earth's surface cooling in response to volcanic aerosols reflecting incoming sunlight. These aerosols also directly add energy to the atmosphere by absorbing outgoing longwave radiation, which is a major cause of precipitation decline in the first post‐eruption year. We additionally identify factors limiting the post‐eruption precipitation decline, and provide evidence that our results are robust across climate models. Plain Language Summary: Large volcanic eruptions can emit gas into the stratosphere that chemically forms sulfate aerosol particles. These aerosols persist in the stratosphere for up to 2 years, and have been linked to widespread precipitation changes in studies based on observations and models. Here we identify the mechanisms through which volcanic aerosols cause their clearest precipitation impact, a temporary reduction in global mean precipitation. Volcanic aerosols globally inhibit precipitation as a result of their abilities to both reflect incoming solar radiation and absorb longwave (terrestrial) radiation. The first is the more important influence on global precipitation, which is reduced for several years as an energetic response to cooler tropospheric temperatures. Absorption of longwave radiation further reduces precipitation during the first post‐eruption year, as a response to the increased energy brought into the stratosphere. Key Points: We identify the mechanisms of volcanic aerosol influence on global precipitation by assessing the atmospheric energy budget in simulationsPost‐eruption precipitation reduction is largely a consequence of a cooler surface, with latent heat balancing a less emissive troposphereVolcanic aerosols absorb outgoing longwave radiation into the stratosphere, and the added energy causes additional precipitation reduction [ABSTRACT FROM AUTHOR]

An arrayed nanocavity-shaped architecture consisting of the key GdFe film and SiO2 dielectric layer is constructed, leading to an efficient infrared (IR) absorption metasurface. By carefully designing and optimizing the film system configuration and the surface layout with needed geometry, a desirable IR radiation absorption according to the spatial magnetic plasmon modes is realized experimentally. The simulations and measurements demonstrate that GdFe-based nanocavity-shaped metasurfaces can be used to achieve an average IR absorption of ~81% in a wide wavelength range of 3–14 μm. A type of the patterned GdFe-based nanocavity-shaped metasurface is further proposed for exciting relatively strong spatial electromagnetic wavefields confined by a patterned nanocavity array based on the joint action of the surface oscillated net charges over the charged metallic films and the surface conductive currents including equivalent eddy currents surrounding the layered GdFe and SiO2 materials. Intensive IR absorption can be attributed to a spatial electromagnetic wavefield excitation and resonant accumulation or memory residence according to the GdFe-based nanocavity-shaped array formed. Our research provides a potential clue for efficiently responding and manipulating and storing incident IR radiation mainly based on the excitation and resonant accumulation of spatial magnetic plasmons. [ABSTRACT FROM AUTHOR]

In this work, we investigate the quasinormal modes (QNMs), shadow radius, gray-body factor, Hawking radiation and absorption cross-section of the Reissner–Nordström black hole surrounded by a cloud of strings in Rastall gravity for a massless scalar field. We use the sixth-order Wenzel, Kramers and Brillouin (WKB) and unstable circular null geodesic methods to calculate QNMs. Moreover, the values obtained by the two methods are in very good agreement. The real part and absolute value of imaginary part of quasinormal frequencies decrease with the increase of a. As q increases, the real part of quasinormal frequencies increases while the absolute value of imaginary part first increases and then decreases. For β > 0, they decrease with the increase of β. While they first increase and then decrease with β increasing at small value of a when β < 0. Then using the unstable circular null geodesic method, we obtain the shadow radius of black hole. We find that shadow radius decreases first and then increases as the negative parameter β increases. We also calculate the gray-body factor. According to it, Hawking radiation and absorption cross-section are calculated. We explore the influence of a, β and q on the energy emission rate. When other parameters are fixed, the black hole lives longer as a, positive parameter β and q increase. To obtain absorption cross-section, we adopt the partial wave method and sinc approximation method, and the results obtained by two methods have excellent consistency at mid-high frequency region. Further, we assess the effect of a, β and q on the absorption cross-section. [ABSTRACT FROM AUTHOR]

The current investigation aims at to examine the effect of radiation absorption, heat generation and Dufour number on MHD Casson fluid flow past an exponentially accelerated vertical plate in a porous medium with chemical reaction. The governing equations for momentum, energy and concentration are solved by implementing the Laplace transformation method. Skin friction, rate of heat transfer and rate of mass transfer expressions are also extracted and depicted in tabular form. Investigation simulates that Casson parameter diminished the fluid velocity, whereas energy flux due to a mass concentration gradient improves the temperature field of the flow problem. In addition to this, temperature field is observed to be developed under the influence of radiation absorption and heat generation. Furthermore, the effects of different non-dimensional parameters on velocity field, temperature fluid and species concentration are exhibited graphically. [ABSTRACT FROM AUTHOR]

The present work reports experimental data on the thermal conductivity of the four hydrocarbons cyclohexane, n-decane, n-hexadecane, and squalane in the liquid state at ambient pressure up to temperatures of 353.15 K. Absolute measurements were performed with a steady-state guarded parallel-plate instrument (GPPI) with an average expanded (coverage factor k = 2) measurement uncertainty of 2 %. For the linear alkanes n-decane and n-hexadecane as well as the cyclic compound cyclohexane, the measured thermal conductivities agree with reference correlations in the literature, indicating the reliability of the technique used for the study of fluids with relatively low thermal conductivities and weak absorption of radiation. For the first time, experimental data are determined for the long-branched alkane squalane between (278 and 353) K, which cannot be accurately represented with estimation methods commonly used in the literature. In summary, the present measurement results confirm the existing database for representative linear and cyclic hydrocarbons and provide first experimental thermal conductivities for squalane. [ABSTRACT FROM AUTHOR]

A type of nanocavity-shaped metasurface for intensively absorbing infrared (IR) radiation in a wide wavelength range of 3–14 μm, which is mainly based on spatial magnetic plasmon excitation and accumulation according to an arrayed nanocavity, is proposed. The basic architecture of the metasurfaces is a layered metal-insulator-metal construction through linear arranging of titanium microribbons and also forming an arrayed titanium microcap on the top of a SiO2 layer preshaped over a thin copper film grown on an n-type silicon wafer, respectively. The measurements present that an average IR absorbing efficiency of more than ∼80% can be easily realized by the metasurfaces constructed. The microribbon-based metasurface exhibits polarization sensitivity under x-polarized incidence. A polarization-independent IR absorption can be conducted through the microcap-based metasurface developed continuously. It should be noted that the proposed nanocavity-shaped metasurfaces can, thus, be featured by an intensive IR absorption essentially attributed to the spatial magnetic plasmon excitation and accumulation or a spatial magnetic field resonant superposition and temporary storage in the multiple nanocavities of the metasurfaces designed. [ABSTRACT FROM AUTHOR]

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Ultra high user density is one of the key requirements in 6G and beyond. Also, in future, THz based communication system and Molecular Communication (MC) will coexist. In such coexist scenarios, Electromagnetic (EM) radiation and in subsequent molecular absorption leads to Radiation Absorption Noise (RAN). However, the RAN and in turn Molecular Information Transfer (MIT) greatly depends on different realistic parameters of human tissues and polarization factor of incident EM radiation. On the other hand, in MC, limited computational capabilities of the information molecules limit them to discriminate against the presence of Bob or Eve. Effect of different parameters of human tissues and polarization factor of incident EM radiation on the secrecy of MC system is modelled and analysed in this research. Basically, this research presents different secrecy measures of the MC system under RAN and therefore, it's effect on MIT is presented. In particular, closed form expressions of different secrecy metrics such as, Secrecy Outage Probability (POUT (Rs)), and Probability of Non-Zero Secrecy Capacity (PNZ-SC (Rs)) are derived in this research work. The effect of impedance of various human tissues like brain, skin and bloods, the effect of polarization factor of incident EM radiation and the effect radiation frequency on each of the proposed secrecy metrics is demonstrated. Different simulated results show a perfect match with the theoretical background. The proposed research is useful in implementation of a secure MC system in a scenario where THz based communication system coexists with MC. [ABSTRACT FROM AUTHOR]

This work presents an in‐depth experimental study aimed at assessing the impact of natural weathering on the behavior of high‐density polyethylene (HDPE) bottles. To this end, several analytical techniques were employed, including Fourier transform infrared spectroscopy (FTIR) to examine molecular changes, scanning electron microscopy (SEM) to study morphology, thermogravimetric analysis (TGA) to assess thermal properties, and tensile and compression tests to evaluate mechanical properties. The results obtained reveal significant changes in HDPE exposed to natural weathering. FTIR analysis enabled us to identify that the HDPE bottles had been subjected to an oxidation process initiated by the absorption of solar radiation during natural weathering treatments, while SEM analysis showed the presence of holes resulting from the detachment of material fragments after exposure, TGA analysis confirms the impact of natural exposure time on the decrease in the average molecular weight and chemical degradation of HDPE macromolecules, through a reduction in the initial degradation temperature and the maximum thermodegradation temperature. However, tensile and compressive tests showed a reduction in the mechanical strength of HDPE after exposure to natural conditions, with notable variations depending on environmental conditions, making the material damaged. These results enabled us to calculate the damage caused by three damage laws. These results offer important insights into the mechanisms of HDPE degradation under the influence of natural climatic factors, paving the way for the development of more resistant and durable packaging materials in the face of variable environmental conditions. Highlights: The objective of this study is to analyze and describe the effects of natural weathering on high‐density polyethylene bottles. This involves evaluating the deterioration of physicochemical, mechanical, and morphological properties. Additionally, three damage laws are employed to assess the extent of damage inflicted by this material.Analytical techniques were used, including SEM, FTIR, and TGA, tensile and compressive test. [ABSTRACT FROM AUTHOR]