Radiative Processes Research Articles

A novel strategy for obtaining essential oil and flavonoids from Thymus vulgaris L. using polyethylene glycol-ultrasonic pretreatment followed by microwave hydrodistillation and extraction

As a medicinal plant with high economic value, the green and efficient separation of the main components (essential oil (EO) and flavonoids) from Thymus vulgaris L. can enhance its application prospects. The present study developed a polyethylene glycol-ultrasonic pretreatment followed by microwave hydrodistillation and extraction (PEG-U-MHDE) technique to distill EO and extract flavonoids simultaneously. The parameters involved in the PEG-ultrasonic pretreatment and microwave irradiation processes were investigated using single factor and BBD experiments, from which 25 % PEG200/400/600 (1:1:1, v/v/v) was found to have the highest extraction ability. Under the optimal conditions, the yield of EO, apigenin, and baicalein was 3.72 ± 0.15 μL/g, 0.76 ± 0.03 mg/g, and 0.96 ± 0.03 mg/g, respectively. The PEG-U-MHDE showed good stability, recovery, and repeatability for apigenin and baicalein. In addition, the separation efficiency of EO, apigenin, and baicalein obtained by PEG-U-MHDE was 0.19 μL/g/min, 37.85 μg/g/min, and 48.03 μg/g/min, respectively, and the EO contained 81.77 % oxygenated compounds, which were higher than other reference methods. The inhibition rate of EO (concentration of 0.5 μL/mL) against the agricultural pathogenic fungus (Fusarium graminearum) was 36.65 ± 1.28 %, which was speculated to be closely related to its main oxygenated compounds (thymol and carvacrol). In general, PEG-U-MHDE has the advantages of short time and high efficiency, and can realize the simultaneous separation of volatile EO and non-volatile components, which provides a theoretical basis for the comprehensive utilization of natural medicinal plants and crops.

Amended Calculation of Solar Heat Gain Coefficient Based on the Escape of Incident Solar Radiation

The solar heat gain is an important component of building cooling load, and its magnitude affects building energy consumption directly. In buildings with glass curtain walls, the window to wall rate is close to 1, so the amount of solar heat gain is huge, which directly determines the energy consumption level of a building’s air conditioning system. In fact, incident solar radiation can escape to the exterior through the transparent envelope, which cannot be ignored in buildings with glass curtain walls. This will cause changes in solar heat gain, so the solar heat gain coefficient (SHGC) needs to be corrected. In this paper, the heat transfer process of solar radiation in window shading systems is analyzed, and an amended calculation model for the SHGC is established. Multiple forms of windows and shading systems are selected and their SHGC-amended factor for rooms with different orientations under different standard calculation conditions in various countries is calculated. As the number of glass layers increases, the transmittance of the window gradually decreases, the reflectance and absorbance gradually increase, and the SHGC value decreases. The SHGC-amended factor decreases with an increasing escape rate, and the two can be approximated as a linear correlation. The weakening effect of shading on the solar heat gain of the buildings is overestimated. The SHGC-amended factor proposed in this paper can calculate building solar heat gain more accurately.

Hybrid GRU–Random Forest Model for Accurate Atmospheric Duct Detection with Incomplete Sounding Data

Atmospheric data forecasting traditionally relies on physical models, which simulate atmospheric motion and change by solving atmospheric dynamics, thermodynamics, and radiative transfer processes. However, numerical models often involve significant computational demands and time constraints. In this study, we analyze the performance of Gated Recurrent Units (GRU) and Long Short-Term Memory networks (LSTM) using over two decades of sounding data from the Xisha Island Observatory in the South China Sea. We propose a hybrid model that combines GRU and Random Forest (RF) in series, which predicts the presence of atmospheric ducts from limited data. The results demonstrate that GRU achieves prediction accuracy comparable to LSTM with 10% to 20% shorter running times. The prediction accuracy of the GRU-RF model reaches 0.92. This model effectively predicts the presence of atmospheric ducts in certain height regions, even with low data accuracy or missing data, highlighting its potential for improving efficiency in atmospheric forecasting.

Environmental Controls on Deep and Overshooting Convection Over the Contiguous U.S.

AbstractDuring the summer season, deep convection over the central United States has a significant impact on the dynamics and composition of the upper troposphere and lower stratosphere (UTLS). These storms transport tropospheric air containing trace gases, ice particles, and aerosols into the UTLS, which can affect chemical and radiative processes over a large region. Because overshooting storms necessarily have strong updrafts, there is a marked correlation between overshooting and the occurrence of severe weather at the surface. Heat released by these storms also helps to drive the North American Monsoon Anticyclone (NAMA) in the UTLS, which partially confines air injected into the stratosphere by overshooting storms. In support of the Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) project, this study is a climatological analysis of the environmental factors that affect the occurrence of deep and overshooting storms. Using hourly analyses of overshooting storms based on GridRad radar data and ERA5 reanalyzes, we focus on the roles of convective available potential energy (CAPE), convective inhibition (CIN), jet location, and other relevant dynamical and thermodynamic variables. The results show that northward intrusion of airmasses containing moist high CAPE air from the Gulf of Mexico into the central plains plays a major role in producing the conditions necessary for overshooting storms with other factors playing secondary roles.

Molecular Characteristics and Processing Technologies of Dairy Products from Non-Traditional Species.

Non-bovine dairy animals, commonly referred to as non-traditional dairy species, include goats, sheep, yaks, buffalo, donkeys, alpacas, llamas, and other less commonly farmed species. These animals have been integral to livestock systems since ancient times, providing milk and other essential products. Despite their historical significance, dairy production from many of these species remains predominantly confined to rural areas in developing countries, where scientific advancements and technical improvements are often limited. As a consequence of this, the scientific literature and technological developments in the processing and characterization of dairy products from these species have lagged behind those for cow's milk. This review aims to compile and analyze existing research on dairy products derived from non-traditional animals, focusing on their molecular characteristics, including proteins (alpha, beta, kappa, and total casein), fats (cholesterol and total fat), lactose, albumin, ash, total solids, and somatic cell count, among others, for each of these species. Additionally, we discuss emerging technologies employed in their processing, encompassing both non-thermal methods (such as high-pressure processing, pulsed electric fields, ultrasound processing, UV-C irradiation, gamma radiation, microfiltration, and cold plasma processing) and thermal methods (such as ohmic heating). This review also explores the specific potential applications and challenges of implementing these technologies. By synthesizing recent findings, we aim to stimulate further research into innovative technologies and strategies that can enhance the quality and yield of non-bovine dairy products. Understanding the unique properties of milk from these species may lead to new opportunities for product development, improved processing methods, and increased commercialization in both developing and developed markets.

Structural Complexity Significantly Impacts Canopy Reflectance Simulations as Revealed from Reconstructed and Sentinel-2-Monitored Scenes in a Temperate Deciduous Forest

Detailed three-dimensional (3D) radiative transfer models (RTMs) enable a clear understanding of the interactions between light, biochemistry, and canopy structure, but they are rarely explicitly evaluated due to the availability of 3D canopy structure data, leading to a lack of knowledge on how canopy structure/leaf characteristics affect radiative transfer processes within forest ecosystems. In this study, the newly released 3D RTM Eradiate was extensively evaluated based on both virtual scenes reconstructed using the quantitative structure model (QSM) by adding leaves to point clouds generated from terrestrial laser scanning (TLS) data, and real scenes monitored by Sentinel-2 in a typical temperate deciduous forest. The effects of structural parameters on reflectance were investigated through sensitivity analysis, and the performance of the 3D model was compared with the 5-Scale and PROSAIL radiative transfer models. The results showed that the Eradiate-simulated reflectance achieved good agreement with the Sentinel-2 reflectance, especially in the visible and near-infrared spectral regions. Furthermore, the simulated reflectance, particularly in the blue and shortwave infrared spectral bands, was clearly shown to be influenced by canopy structure using the Eradiate model. This study demonstrated that the Eradiate RTM, based on the 3D explicit representation, is capable of providing accurate radiative transfer simulations in the temperate deciduous forest and hence provides a basis for understanding tree interactions and their effects on ecosystem structure and functions.

Exploring the Components of Cosmogenic UHECR, Neutrino, and Diffuse Gamma Ray from High-Energy Astrophysical Objects

The development of multimessenger astrophysics allows us to probe various background particles from the distant early universe. Up to now, much effort has been made researching the emission and radiation of diverse steady or transient astrophysical sources. We review the potential accelerating, escaping, propagating, and radiation process of high-energy particles under specific circumstances for regular astrophysical sources and briefly discuss the underlying contribution from their emissions to the intensity of ultrahigh-energy cosmic ray, TeV-PeV cosmic neutrino, and the diffuse gamma-ray background, aiming to find a possible common origin.

Optimal Configuration of Physical Process Parameterization Scheme Combination for Simulating Meteorological Variables in Weather Research and Forecasting Model: Based on Orthogonal Experimental Design and Comprehensive Evaluation Method

The weather research and forecasting (WRF) model is frequently used to investigate the meteorological field around nuclear installations. The configuration of physical process parameterization schemes in the WRF model has a significant impact on the accuracy of the simulation results. Consequently, carrying out a pre-experiment to quickly obtain the optimal combination of parameterization schemes is essential before conducting meteorological parameter research. To obtain the optimal combination of physical process parameterization schemes from the planetary boundary layer (PBL), land surface (LSF), microphysical (MP), long-wave (LW), and short-wave (SW) radiation processes of the WRF model for simulating the near-surface meteorological variables near a nuclear power plant in Sanshan Town, Fuqing City, Fujian Province, China on 4 June 2019 were observed. Orthogonal experimental design (OED), a comprehensive evaluation method based on the CRiteria Import Through Intercriteria Correlation (CRITIC) weight analysis, and comprehensive balance method were employed for the first time to conduct the research. The sensitivity of meteorological variables to physical processes was first discussed. The findings revealed that the PBL scheme configuration had a profound impact on simulating wind fields. Furthermore, the LSF scheme configuration had a significant influence on simulating near-surface temperature and relative humidity, which was much greater than that of other physical processes. In addition, the choice of the radiation scheme had a significant impact on how the temperature was distributed close to the ground and how the wind field was simulated. Furthermore, the configuration of the MP scheme was found to exert a certain influence on the simulation of relative humidity; however, it demonstrated a weak influence on other meteorological variables. Secondly, The MYNN3 scheme for PBL process, the NoahMP scheme for LSF process, the WSM5 scheme for MP process, the RRTMG scheme for LW process, and the Dudhia scheme for SW process are found to be the comprehensive optimal physical process parameterization scheme combination for simulating meteorological variables in the research area selected in this study. As evident from the findings, the use of the OED method to obtain the combinations of the optimal physical process parameterization scheme could successfully reproduce the wind field, temperature, and relative humidity in the current study. Thus, this method appears to be highly reliable and effective for use in the WRF models to explore the optimal combinations of the physical process parameterization scheme, which could provide theoretical support to quickly analyzing accurate meteorological field data for longer periods and contribute to deeply investigating the migration and diffusion behavior of airborne pollutants in the atmosphere.

The Role of Spacers as a Probe in Variation of Photoluminescence Properties of Mono- and Bi-Nuclear Boron Compounds.

A series of N,O donor-based mono- and binuclear four-coordinated boron complexes were synthesized. Depending on the substitution and spacer, these complexes exhibit intense blue, green and yellow emission in solution states. Notably, the fluorescence quantum yields (ΦF) and fluorescence decay (lifetime, τ) of mononuclear boron complexes (2 a-2 e) were higher than the binuclear boron complexes (2 f-2 k). The lowest lifetime and quantum yield in binuclear boron complexes were due to intramolecular rotation induced non radiative processes. The disulphide spacer-based boron complexes 2 i-2 k showed aggregation-caused quenching in the THF/H2O mixture whereas no other complexes were ACQ responsive. These complexes show large Stokes shift, one of them i. e. 2 e has the highest Stokes shift of 130 nm. Further, the electrochemical study suggests the presence of two redox incidences. Theoretical studies show close corroboration between the TD-DFT computed and experimentally measured absorption maxima as well as DFT (GIAO) calculated and experimentally measured 11B NMR values. This complements the appropriate selection of the theoretical methods to shed light on the electronic transitions in the mono- and binuclear BF2 complexes.

Imprint of Diabatic Processes in the Waviness of the Jet Stream: An Analysis of Local Wave Activity Budget

Abstract Given the widespread presence of clouds in the midlatitudes, one expects significant effects of condensational and radiative processes on the large-scale circulation of the atmosphere, but these diabatic effects are hard to constrain from observation. The authors propose a simple method to estimate the diabatic effects on the waviness of the jet stream based on the observed column-mean budget of Rossby wave activity. Wave activity in the midlatitudes is maintained by injection due to surface baroclinicity and/or diabatic sources, downstream transport due to advection and wave radiation, and eventual dissipation through mixing and thermal damping. Once the diabatic sources of wave activity are identified from the residual of the budget, one can suppress them and recompute the budget assuming that the transport velocity and damping rate do not change and thereby assess the impact of the diabatic sources. For the Northern Hemisphere, we found significant positive values of the residual in regions coincident with high column cloud water, suggesting that there are diabatic sources of wave activity associated with clouds. In winter, maritime diabatic sources contribute to wave activity over the Atlantic and the Pacific by about 33% and 30%, respectively, while in summer, the numbers are lower. The estimates are based on the assumptions that the perturbed wave sources do not alter the flow and that sources and sinks are geographically separated. For the Southern Hemisphere, this last assumption is questionable, and therefore, the confidence level of the estimates is low.

Exploring electron-beam induced modifications of materials with machine-learning assisted high temporal resolution electron microscopy

Directed atomic fabrication using an aberration-corrected scanning transmission electron microscope (STEM) opens new pathways for atomic engineering of functional materials. In this approach, the electron beam is used to actively alter the atomic structure through electron beam induced irradiation processes. One of the impediments that has limited widespread use thus far has been the ability to understand the fundamental mechanisms of atomic transformation pathways at high spatiotemporal resolution. Here, we develop a workflow for obtaining and analyzing high-speed spiral scan STEM data, up to 100 fps, to track the atomic fabrication process during nanopore milling in monolayer MoS2. An automated feedback-controlled electron beam positioning system combined with deep convolution neural network (DCNN) was used to decipher fast but low signal-to-noise datasets and classify time-resolved atom positions and nature of their evolving atomic defect configurations. Through this automated decoding, the initial atomic disordering and reordering processes leading to nanopore formation was able to be studied across various timescales. Using these experimental workflows a greater degree of speed and information can be extracted from small datasets without compromising spatial resolution. This approach can be adapted to other 2D materials systems to gain further insights into the defect formation necessary to inform future automated fabrication techniques utilizing the STEM electron beam.

Observing character displacement from process to pattern in a novel vertebrate community

Ecological character displacement, whereby shifts in resource use in the presence of competing species leads to adaptive evolutionary divergence, is widely considered an important process in community assembly and adaptive radiation. However, most evidence for character displacement has been inferred from macro-scale geographic or phylogenetic patterns; direct tests of the underlying hypothesis of divergent natural selection driving character displacement in the wild are rare. Here, we document character displacement between two ecologically similar lizards (Anolis sagrei and A. cristatellus) experiencing novel contact. We identify directional selection during the incipient stages of sympatry in a new community that corresponds to repeated trait divergence across multiple established sympatric communities. By identifying the role of natural selection as character displacement unfolds, we connect how natural selection operating at short timescales may drive broader patterns of trait distributions at larger spatial and temporal scales.

Action of chlorine, peracetic acid, UV-LED radiation, and advanced oxidation process on Giardia lamblia cysts for reclaimed water production

Action of chlorine, peracetic acid, UV-LED radiation, and advanced oxidation process on Giardia lamblia cysts for reclaimed water production

Fabrication of Long-Lasting Superhydrophilic Anti-Fogging Film Via Rapid and Simple UV Process.

Surface fogging is a common phenomenon that can result in restricted visibility, reduced light absorption, and image distortion. Although both hydrophobic and hydrophilic surfaces are effective in preventing this phenomenon, typical coatings in both have limitations, including low durability and the need for frequent reapplication. To address these issues, a highly durable anti-fogging film that lasts over five weeks, even under high moisture conditions, while maintaining a promising degree of transparency (> 60%) is developed. A novel statistical random copolymer containing superhydrophilic and photo-crosslinkable segments that can be simultaneously crosslinked and chemically bonded to various substrates via a simple ultraviolet (UV) irradiation process is synthesized. Notably, the chemical bonding between the anti-fogging coating and substrate improves not only the durability but also the resistance to external forces and environmental changes. Furthermore, this film is versatile and applicable to diverse substrates, such as car windshields, polymer films, and aluminum foil. The innovative strategy offers a simple, rapid process and durable anti-fogging performance with broad applications in the automotive industry, optical devices, and building materials.

In-medium gluon radiation spectrum with all-order resummation of multiple scatterings in longitudinally evolving media

Over the past years, there has been a sustained effort to systematically enhance our understanding of medium-induced emissions occurring in the quark-gluon plasma, driven by the ultimate goal of advancing our comprehension of jet quenching phenomena. To ensure meaningful comparisons between these new calculations and experimental data, it becomes crucial to model the interplay between the radiation process and the evolution of the medium parameters, typically described by a hydrodynamical simulation. This step presents particular challenges when dealing with calculations involving the resummation of multiple scatterings, which have been shown to be necessary for achieving an accurate description of the in-medium emission process. In this paper, we extend our numerical calculations of the fully-resummed gluon spectrum to account for longitudinally expanding media. This new implementation allows us to quantitatively assess the accuracy of previously proposed scaling laws that establish a correspondence between an expanding medium and a “static equivalent”. Additionally, we show that such scaling laws yield significantly improved results when the static reference case is replaced by an expanding medium with the temperature following a simple power-law decay. Such correspondence will enable the application of numerical calculations of medium-induced energy loss in realistic evolving media for a broader range of phenomenological studies.

Extension of the multilevel radiative transfer code PyRaTE to model linear polarization of molecular lines

Linear polarization of spectral lines, commonly known as the Goldreich-Kylafis effect within the star formation community, is one of the most underutilized techniques for probing magnetic fields in the dense and cold interstellar medium. In this study, we implement linear polarization of molecular spectral lines into the multilevel, non-local thermodynamic equilibrium radiative transfer code PyRaTE Different modes of polarized radiation are treated individually, with separate optical depths computed for each polarization direction. Our implementation is valid in the so-called strong magnetic field limit and is exact for either a system satisfying the large-velocity-gradient approximation, and/or for any system with a uniform magnetic field. We benchmark our implementation against analytical results and provide tests for various limiting cases. In agreement with previous theoretical results, we find that in the multilevel case the amount of fractional polarization decreases when compared to the two-level approximation, but this result is subject to the relative importance between radiative and collisional processes. Finally, we post-process an axially symmetric, nonideal magnetohydrodynamic chemo-dynamical simulation of a collapsing prestellar core and provide theoretical predictions regarding the shape (as a function of velocity) of the polarization fraction of $ CO $ during the early stages in the evolution of molecular clouds.

The remarkable microquasar S26: A super-Eddington PeVatron

Context. S26 is an extragalactic microquasar with the most powerful jets ever discovered. They have a kinetic luminosity of Lj ∼ 5 × 1040 erg s−1. This implies that the accretion power to the black hole should be super-Eddington, of the order of Lacc ∼ Lj. However, the observed X-ray flux of this system indicates an apparent very sub-Eddington accretion luminosity of LX ≈ 1037 erg s−1. Aims. We aim to characterize the nature of S26, explain the system emission, and study the feasibility of super-Eddington microquasars as potential PeVatron sources. Methods. We first analyze multi-epoch X-ray observations of S26 obtained with XMM-Newton and model the super-Eddington disk and its wind. We then develop a jet model and study the particle acceleration and radiative processes that occur in shocks generated near the base of the jet and in its terminal region. Results. We find that the discrepancy between the jet and the apparent disk luminosities in S26 is caused by the complete absorption of the disk radiation by the wind ejected from the super-Eddington disk. The nonthermal X-rays are produced near the base of the jet, and the thermal X-rays are emitted in the terminal regions. The radio emission observed with the Australia Telescope Compact Array can be explained as synchrotron radiation produced at the reverse shock in the lobes. We also find that S26 can accelerate protons to PeV energies in both the inner jet and the lobes. The ultra-high energy protons accelerated in the lobes of S26 are injected into the interstellar medium with a total power of ∼1036 erg s−1. Conclusions. We conclude that S26 is a super-Eddington microquasar with a dense disk-driven wind that obscures the X-ray emission from the inner disk, and that the supercritical nature of the system allows the acceleration of cosmic rays to PeV energies.

Physics-informed neural networks for modeling atmospheric radiative transfer

Understanding the radiative transfer processes in the Earth’s atmosphere is crucial for accurate climate modeling and climate change predictions. These processes are governed by complex physical phenomena, which can be generally modeled by the radiative transfer equation (RTE). Solutions to the RTE are obtained by various methods including numerical (standard RTE solvers), stochastic (Monte-Carlo), and data-driven (machine-learning) approaches. This paper introduces a novel numerical approach utilizing a Physics-Informed Neural Network (PINN) to solve the RTE in atmospheric scenarios, applying physics constraints in a machine-learning framework. We show that our PINN model offers a flexible and efficient solution, enabling the simulation of radiance values using plane-parallel atmosphere, and under diverse conditions, including clouds and aerosols.

On the structural and bandgap properties of mist-CVD-grown κ-Ga2O3 post continuous temperature annealing

We investigate the continuous annealing of orthorhombic κ-Ga2O3 films on AlN/c-plane sapphire templates grown by Mist Chemical Vapor Deposition (mist-CVD) using in situ high-temperature x-ray diffraction (HT-XRD). Increasing the annealing temperature from 400 to 1100 °C in both vacuum and ambient air reveals a phase transition onset at 825 °C. High-resolution transmission electron microscopy and XRD demonstrated that annealing within the stability window of 650 to 775 °C effectively improves the crystal quality of the κ-Ga2O3 thin film. Optical transmittance and low-loss electron energy loss spectroscopy (EELS) show the pristine film’s bandgaps to be 4.96 and 4.67 eV, respectively, with reduced bandgaps in annealed films due to increased defect density. EELS-derived optical joint density of states indicates that air-annealing fosters sub-bandgap radiative processes, while vacuum annealing suppresses them, qualitatively correlated with the observed photoluminescence intensity variations. The results of this comprehensive high-temperature annealing study offer crucial insight into the influence of annealing ambient conditions on the crystallographic properties of κ-Ga2O3 films and the associated evolution of extended sub-bandgap states.

Molecular Dynamics Simulation of High-Energy Beam Irradiation of SiO2 Single Crystal with Three Different Morphologies: No Free Surface, with a Free Surface, and Thin Films

Abstract High-energy beam irradiation of SiO2 crystal with the α-quartz structure was simulated by the molecular dynamics method. Three types of specimen structures were examined: a single crystal without a free surface, a single crystal with a free surface, and a thin film. After structural relaxation at room temperature, a cylindrical region with diameter of 3.0 nm was set at the center of the specimen and high-thermal energy of Seff = 0.1 – 2.5 keV/nm was added to that region, where Seff is the effective stopping power. Atomic motions were calculated by the molecular dynamics method using the large-scale atomic/molecular massively parallel simulator). Vashishta potential was used for the atomic interaction. The single crystal structure of α-quartz without the free surface was stable up to 1.0 keV/nm and it gradually became amorphous with increasing thermal energy. In contrast, the single crystal structure with the free surface was stable up to 0.5 keV/nm and was amorphous at higher thermal energy. In particular, the atomic structures for the thermal impact Seff ≥ 2.0 keV/nm had a facet-like structure at the impacted surface, which corresponds to actual experimental results. Nano-hole formation was observed in the irradiation process of the film structure.