Radiation Energy Research Articles

Study on Seismic Source Parameter Characteristics of Baihetan Reservoir Area in the Lower Reaches of the Jinsha River

The source parameters of earthquakes (stress drop, corner frequency, seismic moment, source size, radiant energy, etc.) provide important information about the source features, the state of stress, and the mechanism of earthquake rupture dynamics. Using the digital observation data obtained from a high-density seismic monitoring network deployed in the Baihetan reservoir area of the lower Jinsha River, we obtained Brune source parameters of the 459 earthquakes ranging in magnitude ML 1.50~4.70. The results revealed seismic moments M0 within the range of 2.03 × 1012~1.45 × 1016 N·m, corner frequencies fc between 2.00 and 10.00 Hz, and source dimensions varying from 130.00 to 480.00 m, with stress drops spanning from 0.12 to 61.24 MPa. It is noteworthy that the majority of the earthquakes had stress drops less than 10.00 MPa, with as much as 73.30% of these events having stress drops within the range of 0.10 to 2.00 MPa. We found that stress drop, corner frequency, and source size in the study area exhibited positive correlations with earthquake magnitude. Earthquakes occurring at shallower depths for the same magnitude tended to have smaller stress drops and corner frequencies, but larger rupture scales. During the first 2 years of impoundment with significant water level fluctuation, earthquakes beneath or near the reservoir released higher stress drops relative to pre-reservoir conditions, with average stress drops significantly elevated from 5.52 to 13.562 Mpa for events above ML3 since the impoundment. The radiated energy released by earthquakes with magnitudes below ML3.0 are significantly more than before impoundment, indicating that earthquakes of similar magnitudes in the reservoir area may produce greater intensity and perceptibility following the impoundment. According to our result, the triggered seismicity will continue to be active under annual regulation changes in the water level of the Baihetan Dam at high elevations in future years.

RHDLPP: A multigroup radiation hydrodynamics code for laser-produced plasmas

In this paper, we introduce the RHDLPP, a flux-limited multigroup radiation hydrodynamics numerical code designed for simulating laser-produced plasmas in diverse environments. The code bifurcates into two packages: RHDLPP-LTP for low-temperature plasmas generated by moderate-intensity nanosecond lasers, and RHDLPP-HTP for high-temperature, high-density plasmas formed by high-intensity laser pulses. The core radiation hydrodynamic equations are resolved in the Eulerian frame, employing an operator-split method. This method decomposes the solution into two substeps: first, the explicit resolution of the hyperbolic subsystems integrating radiation and fluid dynamics; second, the implicit treatment of the parabolic part comprising stiff radiation diffusion, heat conduction, and energy exchange. Laser propagation and energy deposition are modeled through a hybrid approach, combining geometrical-optics ray-tracing in sub-critical plasma regions with a one-dimensional solution of the Helmholtz wave equation in super-critical areas. The thermodynamic states are ascertained using an equation of state, based on either the real gas approximation or the quotidian equation of state (QEOS). For ionization calculations, the code employs a steady-state collisional-radiation (CR) model using the screened-hydrogenic approximation. Additionally, RHDLPP includes RHDLPP-SpeIma3D, a three-dimensional spectral simulation post-processing module, for generating both temporally-spatially resolved and time-integrated spectra and imaging, facilitating direct comparisons with experimental data. The paper showcases a series of verification tests to establish the code's accuracy and efficiency, followed by application cases, including simulations of laser-produced aluminium (Al) plasmas, pre-pulse-induced target deformation of tin (Sn) microdroplets relevant to extreme ultraviolet lithography light sources, and varied imaging and spectroscopic simulations. These simulations highlight RHDLPP's effectiveness and applicability in fields such as laser-induced breakdown spectroscopy, extreme ultraviolet lithography sources, and high-energy-density physics.

Data analysis of non-linear radiative electro-periodic MHD flow past a stretching sheet with activation energy impact

Electro-periodic Magneto-hydrodynamics (EPMHD), activation energy, and non-linear radiation are pivotal elements in engineering and industry also contribute to advancements in fields like heat transfer, materials science, and chemical engineering. Through similarity transformation, governing partial differential equations simplify into ordinary differential equations. Precise computational solutions are derived using the Nachtsheim-Swigert shooting iteration method (NSSIM) and the reliable 6th-order Runge-Kutta integration algorithm (RKIA). The profiles of velocities, temperatures, concentrations, skin friction, heat and mass transfer rate are presented by graphically. The novel aspect of this research is that thermal performance is enhanced by non-linear radiation by around 2.28%, whereas linear radiation only produces a 0.28% improvement in thermal performance. Also the mass transfer rate experiences a decrease of about 25.76% with increasing chemical reactions in the presence of activation energy and a more substantial 62.22% reduction in its absence, notably showing a comparatively milder decline of 36.46% in the presence of activation energy than in its absence. Furthermore, this study yields three novel linear regression equations, skillfully derived from the numerical and graphical results. This research have practical applications in understanding and optimizing processes involving fluid dynamics, such as the behavior of certain materials or substances subjected to stretching or deformation.

Advanced fusion of MTM-LSTM and MLP models for time series forecasting: An application for forecasting the solar radiation

Accurate time series forecasting has become increasingly important across various domains such as finance, energy, and medicine. This study introduces an innovative hybrid model that leverages the power of neural networks, precisely Many To Many LSTM (MTM LSTM) and Multilayer Perceptron (MLP), to improve time series forecasting accuracy. In this new combination, we trained network MTM LSTM to approximate the target at each step, and finally, we used network MLP to combine these approximations. To perform the evaluation, we made a forecast for the amount of solar energy radiation in the city of Mashhad, Iran. The experiment results concerning MSE and MAE showed that the proposed method with five lags outperforms the standard models.We hypothesize that MTM LSTM can effectively capture solar radiation's intricate temporal dependencies and nonlinearity. At the same time, MLP can enhance function approximation by modeling complex interactions, resulting in improved forecast accuracy. By employing the hybrid MTM LSTM and MLP model, we achieved improved accuracy in predicting solar energy radiation, which has significant implications for the renewable energy sector and its energy management and planning applications. This research advances time series forecasting techniques, highlighting the effectiveness of combining neural networks to address complex and dynamic patterns in time-dependent data.Overall, our findings underscore the potential and efficacy of the proposed hybrid model as a robust tool for accurate time series forecasting in various domains, supporting effective decision-making and planning processes.

Assessing Lidar Ratio Impact on CALIPSO Retrievals Utilized for the Estimation of Aerosol SW Radiative Effects across North Africa, the Middle East, and Europe

North Africa, the Middle East, and Europe (NAMEE domain) host a variety of suspended particles characterized by different optical and microphysical properties. In the current study, we investigate the importance of the lidar ratio (LR) on Cloud-Aerosol Lidar with Orthogonal Polarization–Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIOP-CALIPSO) aerosol retrievals towards assessing aerosols’ impact on the Earth-atmosphere radiation budget. A holistic approach has been adopted involving collocated Aerosol Robotic Network (AERONET) observations, Radiative Transfer Model (RTM) simulations, as well as reference radiation measurements acquired using spaceborne (Clouds and the Earth’s Radiant Energy System-CERES) and ground-based (Baseline Surface Radiation Network-BSRN) instruments. We are assessing the clear-sky shortwave (SW) direct radiative effects (DREs) on 550 atmospheric scenes, identified within the 2007–2020 period, in which the primary tropospheric aerosol species (dust, marine, polluted continental/smoke, elevated smoke, and clean continental) are probed using CALIPSO. RTM runs have been performed relying on CALIOP retrievals in which the default and the DeLiAn (Depolarization ratio, Lidar ratio, and Ångström exponent)-based aerosol-speciated LRs are considered. The simulated fields from both configurations are compared against those produced when AERONET AODs are applied. Overall, the DeLiAn LRs leads to better results mainly when mineral particles are either solely recorded or coexist with other aerosol species (e.g., sea-salt). In quantitative terms, the errors in DREs are reduced by ~26–27% at the surface (from 5.3 to 3.9 W/m2) and within the atmosphere (from −3.3 to −2.4 W/m2). The improvements become more significant (reaching up to ~35%) for moderate-to-high aerosol loads (AOD ≥ 0.2).

Superhydrophobic, Highly Conductive, and Trilayered Fabric with Connected Carbon Nanotubes for Energy-Efficient Electrical Heating.

Current electrically heated fabrics provide heat in cold climates, suffer from abundant wasted radiant heat energy to the external environment, and are prone to damage by water. Thus, constructing energy-efficient and superhydrophobic conductive fabrics is in high demand. Therefore, we propose an effective and facile methodology to prepare a superhydrophobic, highly conductive, and trilayered fabric with a connected carbon nanotube (CNT) layer and a titanium dioxide (TiO2) nanoparticle heat-reflecting layer. We construct polyamide/fluorinated polyurethane (PA/FPU) nanofibrous membranes via first electrospinning, then performing blade-coating with the polyurethane (PU) solution with CNTs, and finally fabricating FPU/TiO2 nanoparticles via electrospraying. This strategy causes CNTs to be connected to form a conductive layer and enables TiO2 nanoparticles to be bound together to form a porous, heat-reflecting layer. As a consequence, the as-prepared membranes demonstrate high conductivity with an electrical conductivity of 63 S/m, exhibit rapid electric-heating capacity, and exhibit energy-efficient asymmetrical heating behavior, i.e., the heating temperature of the PA/FPU nanofibrous layer reaches more than 83 °C within 90 s at 24 V, while the heating temperature of the FPU/TiO2 layer only reaches 53 °C, as well as prominent superhydrophobicity with a water contact angle of 156°, indicating promising utility for the next generation of electrical heating textiles.

Using the urban environment for conservation of rare understory shrub species Daphne jejudoensis and Maesa japonica

To investigate the potential for urban environments on Jeju Island, South Korea, to support the conservation of rare understory shrub species, specifically Daphne jejudoensis and Maesa japonica with limited habitat availability, several study sites were selected to assess the performance of these plants after transplanting. A study site similar to the original habitat (Fo), sites between building gaps (GapJ and GapC), a flowerbed in front of a building (FbJ), the rooftop of a building (Roof), and indoor terraces at higher latitude areas (TeSD and TeSM) were selected. Building gap sites and terrace sites displayed similar but a little lower canopy coverage to the forest site (80−90 %). The flowerbed site showed ∼ 50 % coverage, and the Roof site showed ∼ 30 % canopy coverage. Therefore, urban environmental sites (GapJ, GapC, TeSD, and TeSM) displayed similar canopy coverage to original habitats of D. jejudoensis and M. japonica, with stronger light intensity than the Fo site. Shortwave radiation energy from the sky hemisphere at urban environmental sites was only 15−50 % that of the Roof site and only 3 % that of the Fo site. Therefore, urban environmental sites displayed intermediate radiation between canopy open areas and forest sites. This increased light intensity and radiation led to significantly better performance for both shrub species in terms of photosynthetic rate, water use efficiency, and chlorophyll content at urban environmental sites compared with canopy-opened Roof sites. Furthermore, these sites supported similar plant growth for D. jejudoensis and better growth for M. japonica compared with the Fo site. Therefore, urban environments possess huge potential for successful conservation of rare tree species with limited habitat range. Additionally, results for terrace sites suggest that D. jejudoensis and M. japonica have great potential as indoor gardening plants, which could support species conservation through public engagement. As a pioneering study, our findings highlight the great potential for species conservation using stable and accessible urban environments around buildings.

Observational Assessment of Changes in Earth’s Energy Imbalance Since 2000

AbstractSatellite observations from the Clouds and the Earth’s Radiant Energy System show that Earth’s energy imbalance has doubled from 0.5 ± 0.2 Wm−2 during the first 10 years of this century to 1.0 ± 0.2 Wm−2 during the past decade. The increase is the result of a 0.9 ± 0.3 Wm−2 increase absorbed solar radiation (ASR) that is partially offset by a 0.4 ± 0.25 Wm−2 increase in outgoing longwave radiation (OLR). Despite marked differences in ASR and OLR trends during the hiatus (2000–2010), transition-to-El Niño (2010–2016) and post-El Niño (2016–2022) periods, trends in net top-of-atmosphere flux (NET) remain within 0.1 Wm−2 per decade of one another, implying a steady acceleration of climate warming. Northern and southern hemisphere trends in NET are consistent to 0.06 ± 0.31 Wm−2 per decade due to a compensation between weak ASR and OLR hemispheric trend differences of opposite sign. We find that large decreases in stratocumulus and middle clouds over the sub-tropics and decreases in low and middle clouds at mid-latitudes are the primary reasons for increasing ASR trends in the northern hemisphere (NH). These changes are especially large over the eastern and northern Pacific Ocean, and coincide with large increases in sea-surface temperature (SST). The decrease in cloud fraction and higher SSTs over the NH sub-tropics lead to a significant increase in OLR from cloud-free regions, which partially compensate for the NH ASR increase. Decreases in middle cloud reflection and a weaker reduction in low-cloud reflection account for the increase in ASR in the southern hemisphere, while OLR changes are weak. Changes in cloud cover in response to SST increases imply a feedback to climate change yet a contribution from radiative forcing or internal variability cannot be ruled out.

Quasi-bound state in the continuum in a dielectric double-gap split-ring metasurface structure with large split angles

It was reported previously that the quality factor of a symmetry-protected quasi-BIC mode increases as the degree of structure asymmetry is reduced. In this work, we propose and investigate an alternative approach to increase the quality factor of a quasi-BIC mode without reducing the degree of asymmetry. Specifically, we calculate the quality factor of the quasi-BIC mode of a double-gap dielectric split-ring metasurface for different split angles. It is found that the quality factor increases exponentially with the increase of the split angles while the degree of asymmetry of the structure is constant. To explain the phenomena, multipole moment decomposition of the local electromagnetic field is conducted to calculate the change of major multipole moments versus the split angles. It is revealed that the double-gap split-ring array structure stores more energy in the higher order multipoles, and the rate of radiation energy loss stays constant when the two splitting angles increase simultaneously. Additionally, the enhancement of third harmonic generation is investigated in the double-gap split-ring metasurface structure.

Photocatalytic degradation of paracetamol on immobilized TiO2 in a low-tech reactor by solar light for water treatment

Photocatalytic water treatment is an appealing concept to mineralize organic contaminants in contaminated water. In this study, the UV-resistant drug paracetamol (PCT) in aqueous solution is degraded by using a solar irradiated loop-reactor equipped with a TiO2 (P25) photocatalyst. The catalyst powder was dispersed in a geopolymer surface coating applied to aluminum-U-profiles connected by filament-printed polymer elements. Different assays with variations in initial PCT concentration were performed under natural solar radiation to determine the degradation kinetics of the PCT and correlate it to applied solar radiation energy density. Depending on experimental conditions, degradation efficiencies of 37.0–75.1 % were achieved within 3 h. Control samples without catalyst show no degradation. No degradation of the catalyst activity was observed within 42 h of operation time. The study shows the feasibility of this simple and scalable reactor design and coating technology for water purification under off-grid conditions provided sufficient solar radiation is available.

Project Hephaistos – II. Dyson sphere candidates from Gaia DR3, 2MASS, and WISE

ABSTRACT The search for extraterrestrial intelligence is currently being pursued using multiple techniques and in different wavelength bands. Dyson spheres, megastructures that could be constructed by advanced civilizations to harness the radiation energy of their host stars, represent a potential technosignature, that in principle may be hiding in public data already collected as part of large astronomical surveys. In this study, we present a comprehensive search for partial Dyson spheres by analysing optical and infrared observations from Gaia, 2MASS, and WISE. We develop a pipeline that employs multiple filters to identify potential candidates and reject interlopers in a sample of five million objects, which incorporates a convolutional neural network to help identify confusion in WISE data. Finally, the pipeline identifies seven candidates deserving of further analysis. All of these objects are M-dwarfs, for which astrophysical phenomena cannot easily account for the observed infrared excess emission.

Analysis of Dyonic ModMax black hole through accretion disk

In the present study, we probe the geodesic motion and accretion of particles around the spherically symmetric Dyonic ModMax black hole using isothermal fluid. The geodesic motion of the particles around the black hole leads to the formation of disk like structure during the accretion process. We compute the radiant temperature, radioactive efficiency, radiant flux energy, circular orbits and observe the behavior of particles within stable circular orbits in the equatorial plane. We examine how the particles are perturbed during the process by using restoring forces and the oscillatory behavior of the particles surrounding a compact object and also investigate the fluid’s critical flow and maximum accretion rate. Our findings demonstrate how the black hole parameter γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma $$\\end{document} and charge Q affect the circular geodesic of particles as well as the maximum accretion rate of the Dyonic ModMax black hole.

Exploration Of Key Approaches to Enhance Evacuated Tube Solar Collector Efficiency

Exploration Of Key Approaches to Enhance Evacuated Tube Solar Collector Efficiency

Magic speed under radiation drag for the optically thick outflows and SS 433 jets

Abstract One of the promising mechanisms to explain the stable jet speed of SS 433 is the magic speed, which is established by the balance between radiation pressure and radiation drag (and gravity). We examine the magic speed in the optically thick sub-relativistic flows for several typical situations, such as plane-parallel and spherical cases, and show that it is difficult to establish the magic speed in the simple optically thick flows in contrast to the optically thin ones. Instead, we propose the funnel jets as an improved model. That is, we consider the optically thick flows in the funnel, which is formed by the supercritical accretion disk, and mass and radiation energy are injected from the funnel wall. In this model the mass-accretion rate determines the configuration of the funnel, the increasing mass-loss rate of jets, the radiative environments, and then the sub-relativistic magic speed is naturally established.

Numerical investigation of heat transfer enhancement in magnetohydrodynamics ternary ferrofluids on nonlinear stretching sheet

The current study examines the complex interaction between mass and thermal energy variations, considering factors including activation energy, chemical reactions, and thermal radiation across a nonlinear stretching sheet. The ternary nanofluid comprises titanium, single-walled carbon nanotubes, and multi-walled carbon nanotubes to improve the heat transfer characteristics of the fluidic system. Partial differential equations are utilized to represent the system’s dynamic behavior mathematically. Following this, similarity transformations are used to convert these governing partial differential equations into ordinary differential equations. The numerical solution for the transformed boundary value equations is derived using MATLAB. The graphical representations explain the results of these calculations, providing clear insights into the behavior of important variables in various conditions. It is concluded that an increase in the flexibility parameter improves the thermal behavior of a fluid, while an increase in the Prandtl parameter decreases it. Furthermore, applying a magnetic field to the dynamics of fluid heating enhances temperature and energy transfer.

Holographic massive plasma state in Friedman universe: cosmological fine-tuning and coincidence problems

Massive particle and antiparticle pair production andoscillation on the horizon form a holographic and massive pair plasma state in the Friedman Universe. Via this state, the Einsteincosmology term (dark energy) interacts with matter and radiation and is time-varying Λ̃ in the Universe's evolution.It is determined by a close set of ordinary differential equations for dark energy, matter, and radiation energy densities. The solutions are unique, provided the initial conditions given by observations.In inflation and reheating, dark energy density decreases from the inflation scale, converting to matter and radiation energy densities.In standard cosmology, matter and radiation energy densities convert to dark energy density, reaching the present Universe. By comparing with ΛCDM, quintessence and dark energy interacting models, we show thatthese results can be the possible solutions for cosmological fine-tuning and coincidence problems.

Relativistic Jet Ejections from Slim Disks

A mechanism for the ejection of relativistic jets from slim disks is studied. Since radiation pressure is dominant in the slim disk, radiative energy flows along the pressure gradient in the vertical direction. The divergence of the radiative flux tells us that the flow of radiative energy from a bottom layer near the equatorial plane is absorbed by another layer above the boundary surface. The absorbed energy accumulates in the upper layer as the matter advances inward, and calculations show that the specific energy of the flow in the upper layer can be as large as ∼c 2 near the black hole when the accretion rate through the upper layer is relatively low. Since the specific energy ∼c 2 is much larger than the gravitational energy, the height of the upper layer could significantly increase then. Hence, the innermost part of the upper layer after almost all the angular momentum has been removed could have a much greater height than the size of the black hole, and the flow could collide with itself around the central axis of the disk, bouncing back from the axis while simultaneously expanding along it. The flow is expected to go outward along the central axis and to become supersonic due to the change in its cross section, finally producing relativistic jets.

Optimization of conditions for excitation of Xe laser plasma in an extreme ultraviolet radiation source for nanolithography in order to increase its efficiency

Subject of study. The study focuses on laser plasma excited by a Xe gas-jet target. Aim of study. The aim of this study is to increase the output of extreme ultraviolet radiation from such a plasma to a level that meets the requirements of industrial production, specifically for use as a radiation source in a new branch of lithography with a wavelength near 11.2 nm. Method. The primary method used involves changing the diameter of the laser beam by moving a Xe gas-jet target along its axis. This adjustment leads to a change in the interaction area between the beam and the target, which in turn alters the size of the laser spark. The intensity of plasma radiation at wavelengths of 11.2 nm and 13.5 nm was measured using a surface-barrier Si photosensor and a Bragg mirror. Additionally, the energy of the laser radiation absorbed by the plasma was measured. Main results. The results show that, when the diameter of the laser beam illuminating the target increases from 46 µm to 344 µm, the energy emitted in the extreme ultraviolet range increases by approximately 5 times. In the identified irradiation mode, the efficiency of converting laser radiation into radiation with a wavelength of 11.2 nm was 3.9%. Recent measurements of the plasma lifetime have shown that it depends on the size of the plasma and, in several experiments, is significantly shorter than the laser pulse duration. This finding suggests that the plasma lifetime can be used as an optimization parameter when selecting the laser pulse duration. Practical significance. A record-high efficiency is obtained for the conversion of laser pulse energy into extreme ultraviolet radiation by a laser-plasma radiation source with a gas target. This achievement opens up the prospect of using such sources in the industrial production of microcircuits.

Increase in Power of Radiation and Specific Concentration of Energy of Plasma of the High-Current Z-Pinches due to Compression of the Cascade Wire Arrays Interacting via Magnetic Field

Increase in Power of Radiation and Specific Concentration of Energy of Plasma of the High-Current Z-Pinches due to Compression of the Cascade Wire Arrays Interacting via Magnetic Field

A study on the impact of solar radiations and activation energy effects in existence of nanofluid over stretching solar sheets

In this paper, we study the effects of activation energy and solar radiation on expanding solar sheets, as well as non-Newtonian nanofluid dynamics, which are important in these applications and are driving efforts to find solutions to the world’s energy problems. We provide numerical solutions to physical flow problems by solving partial differential equations. We utilise the MATLAB-integrated bvp4c methodology after applying similarities to turn these PDEs model into ODEs. By investigating dimensionless momentum, concentration, and thermal profiles under different conditions, our research delves into the physical relevance of nanofluids. Important flow field components have also been numerically and tabulatively studied and displayed graphically. The rates at which heat is transferred is 29.06% and 37.99%, respectively. The rate of heat transport rose by 13.93% as a result. At greater values for the Maxwell fluid parameter, the velocity profiles improved while the temperature profiles decreased. This paper contributes significant new information to the ongoing discussion in this area, which is in line with earlier findings.