Transmission Of Radiation Research Articles

Seasonality of spectral radiative fluxes and optical properties of Arctic sea ice during the spring–summer transition

The reflection, absorption, and transmittance of shortwave solar radiation by sea ice play crucial roles in physical and biological processes in the ice-covered Arctic Ocean and atmosphere. These sea-ice optical properties, particularly during the melt season, significantly impact energy fluxes within and the total energy budget of the coupled atmosphere-ice-ocean system. We analyzed data from autonomous drifting stations to investigate the seasonal evolution of the spectral albedo, transmittance, and absorptivity for different sea-ice, snow, and surface conditions measured during the MOSAiC expedition in 2019–2020. The spatial variability of these properties was small during spring and increased strongly after melt onset on May 26, 2020, when liquid water content on the surface increased, largely accounting for the enhanced variability. The temporal evolution of surface albedo and sea-ice transmittance was mostly event-driven, thus containing episodic elements. Melt ponds reduced the local surface albedo by 31%–45%. Over the melting season, single ponding events increased the energy deposition of the sea ice by 35% compared to adjacent bare ice. Thus, single melt ponds may impact the summer energy budget as much as seasonal evolution over 1 month. Absorptivity and transmittance showed strong temporal and spatial variabilities independently of surface conditions, possibly due to the different internal sea-ice properties and under-ice biological processes. The differences in seasonal evolution shown for different sea-ice conditions strongly impacted the partitioning of shortwave solar radiation. This study shows that the formation and development of melt ponds, in reducing albedo by a third of bare ice sites, can notably increase the total summer heat deposition. The vastly different seasonal evolutions, different sea-ice conditions, and timing and duration of ponding events need to be considered when comparing local in-situ observations with large-scale satellite remote sensing datasets, which we suggest can help to improve numerical models.

Plasma Response of a Metallic “Grating” Metasurface on a Substrate

The transmission of electromagnetic radiation through a silicon substrate with a square metallic grid deposited on one side has been studied experimentally. It has been established that the electrodynamic response of the structure is equivalent to the excitation of a transverse electromagnetic plasma mode in it with the plasma frequency determined by the geometric parameters of the grating, as well as by the thickness and relative permittivity of the substrate. A theoretical model has been developed to qualitatively describe the experimental results obtained.

Determination of interparticle radiative heat transfer and radiation absorption for ellipsoidal particle beds using Monte Carlo ray tracing

The calculation of radiative heat transfer between particles in particle-based solar systems presents significant challenges in terms of computational cost and accuracy. This study addresses these challenges by employing the discrete element method to generate random particle packings and the Monte Carlo ray tracing method to investigate the influence of particle shape and volume fraction (ϕ) on interparticle radiation transfer and the absorption of incident radiation. The results reveal that, at low volume fractions, the shape and orientation of ellipsoidal particles have a pronounced impact on direct radiative transfer. Oblate particles exhibit the highest average radiation distribution factor (RDF), and the dispersion of RDF data is more prominent for oblate and elongated prolate particles compared to spheres. As ϕ increases to 0.35, the contribution of indirect transfer from neighboring particles becomes significant for oblate particles, resulting in a reduction in the dispersion of RDF data. Furthermore, when ϕ reaches 0.55, the decisive factor in determining RDF becomes the shielding effect of particles positioned between the emitting and receiving particles. The average RDF tends to converge among particles of different shapes, although oblate and elongated prolate particles still exhibit considerably larger RDF dispersion compared to spherical and near-spherical particles. Additionally, the effective absorptivity of the particle bed for incident radiation decreases as the aspect ratio of particles increases at all volume fractions. Moreover, the transmitted fraction demonstrates an exponential relationship with the depth, and beds composed of spherical particles exhibit better radiation transmittance compared to beds containing non-spherical particles.

Multimodal aircraft flight altitude inversion from SDGSAT-1 thermal infrared data

Accurately detecting and localizing high-speed aircraft is significant for monitoring global flight activities, conducting searches, and performing emergency rescues. Typically, the spatial position of an air target is obtained through active communication or multi-satellite observation. Here, we propose a multimodal flight altitude inversion method using a single thermal infrared payload (SDGSAT-1 TIS). Space-based longwave thermal infrared is a passive detection method that can measure the surface thermal radiation of objects and capture radiation differences caused by flying aircraft against the background, thereby providing an opportunity for their detection and location. Considering geographic location, time, climate, and aircraft size, we establish a framework to integrate the radiation transmission model with three-spectral-band remote sensing data. This proposed framework elucidates the relationship between flight altitude and top-of-atmosphere radiance, realizing the inversion from thermal infrared remote sensing images to altitude. Validated on 100 aircraft, the proposed framework achieved an average altitude measurement accuracy of 0.508 km compared with Flightradar24. This research provides a unique solution for the all-time passive localization of air targets.

Attenuation coefficient for Agarwood and shade tree sections at 59.6keV and 356keV

Attenuation coefficient for Agarwood and shade tree sections at 59.6keV and 356keV

Multifitting 2: software for reflectometric, off-specular and grazing-incidence small-angle scattering analysis of multilayer nanofilms

Multifitting is a computer program that was originally designed to model the reflection and transmission of shortwave radiation by multilayer nanofilms. Three years have passed since the introduction of this software, and in this paper the focus is on describing the possibilities of Multifitting with regard to off-specular diffuse scattering and grazing-incidence small-angle scattering. The approach to the user interface and to working with the structure model remains the same, and the emphasis is on the ergonomics, calculation speed and intensive use of the program for technological and research tasks. However, the scope of the program has been expanded to make it more useful to existing users, and it may also be of interest to a wider audience.

Sustainable, low-cost, high-contrast electrochromic displays via host–guest interactions

Electrochromic (EC) displays with electronically regulating the transmittance of solar radiation offer the opportunity to increase the energy efficiency of the building and electronic products and improve the comfort and lifestyle of people. Despite the unique merit and vast application potential of EC technologies, long-awaited EC windows and related visual content displays have not been fully commercialized due to unsatisfactory production cost, durability, color, and complex fabrication processes. Here we develop a unique EC strategy and system based on the natural host and guest interactions to address the above issues. A completely reusable and sustainable EC device has been fabricated with potential advantages of extremely low cost, ideal user-/environment friendly property, and excellent optical modulation, which is benefited from the extracted biomass EC materials and reusable transparent electrodes involved in the system. The as-prepared EC window and nonemissive transparent display also show comprehensively excellent properties: high transmittance change (>85%), broad spectra modulation covering Ultraviolet (UV), Visible (Vis) to Infrared (IR) ranges, high durability (no attenuation under UV radiation for more than 1.5 mo), low open voltage (0.9 V), excellent reusability (>1,200 cycles) of the device's key components and reversibility (>4,000 cycles) with a large transmittance change, and pleasant multicolor. It is anticipated that unconventional exploration and design principles of dynamic host-guest interactions can provide unique insight into different energy-saving and sustainable optoelectronic applications.

Studies on structural, optical, thermal and low energy shielding for gamma rays for the ZSBP glasses

By employing the melt-quenching technique, the ZnO–SrO–B2O3–PbO (ZSBP) glasses have been successfully fabricated. The derivative of Absorption Spectra Fitting (DASF) method was used to study the energy band gap (Eg) of the glasses which decreases from 3.57 eV to 3.39 eV. The structural properties have been studied using the Raman spectroscopy. The glass transition temperature (Tg) decreases with increase in concentration of the lead oxide. The current study examines the radiation shielding properties at 30.80–444 keV. The addition of PbO to the glasses resulted in a proportionate increase in the mass attenuation coefficient (MAC), suggesting a diminishing tendency in radiation transmission. At 30.80 keV, the MAC values are extremely high and range from 18.06 to 21.11 cm2/g. As density rises, the half value layer (HVL) decreases. In addition, the average HVL (HVL‾) decreases. The glass thickness required to reduce the radiation intensity to 90 %, 50 %, 25 %, and 10 % of its initial value is investigated at an energy of 35.80 keV. The T90 %, T50 %, T25 %, and T10 % values are 0.0020, 0.0132, 0.0264, and 0.0439 cm, respectively. The results suggest that a greater thickness of the radiation barrier is necessary to attain the necessary degree of attenuation.

ON THE ISSUE OF COMPREHENSIVE ASSESSMENT OF THE IMPACT OF THERMAL RADIATION AT WORKPLACES, TAKING INTO ACCOUNT AIR POLLUTION

Problem statement. The research demonstrates that existing methods for determining the distribution of thermal radiation intensity using nomograms and formulas contain significant errors. This is due to the adoption of a number of simplifications regarding numerous interdependent parameters, including the temperature inside furnaces, the size of openings and shafts, etc. As a result, there is a need for measurements of thermal radiation intensity at distances of 5−10 meters and beyond. The purpose of the article. The objective of the article is to propose a concept for a new experimental methodology to investigate the intensity of radiation exposure to workers at their workplaces. Simultaneously, in order to address the issues of thermal protection for workers, actual measurement data of thermal radiation levels are necessary for each workstation under real working conditions within the workspace. Conclusion. It is important to characterize the composition of the gas environment, as its impurities can distort the distribution of radiant energy through interference and diffraction effects, which need to be considered for microclimate optimization. The presence of dust particles complicates the straight-line heat transfer through scattering and scintillation of rays, requiring further improvement of models. Turbulence, impurities, and atmospheric heterogeneity are important factors that need to be further investigated and taken into account in heat transfer process modeling. Scintillation affects the quality of radiation transmission, necessitating further study of this phenomenon. Local atmospheric composition peculiarities require the development of models that consider these variations. The obtained experimental data will contribute to improving the accuracy of modeling and enhancing working conditions. Further refinement of measurement techniques is necessary for obtaining reliable information.

Egg-tray-inspired concave foam structure on pore-scale space radiation regulation for enhancing photo-thermal-chemical synergistic conversion

Solar-to-fuel is an approach of converting concentrated solar high-temperature heat radiation to high-value chemical fuel, providing sustainable means for large-scale solar energy storage. However, the inefficient space radiation regulation and unclear photo-thermal-chemical multiphysics synergy limit solar to fuel conversion. To effectively improve photo-thermal-chemical conversion, here, we propose a novel idea of using an egg-tray-inspired concave structure in foam solar receiver-reactors for pore-scale space radiation regulation. The multiphysics field coupling model is accurately constructed to truly describe the complex radiation energy conversion process. Experimental and numerical results illustrate that, the proposed egg-tray-inspired concave structure can achieve the better radiation absorption and transmission, multi-field synergy and thermochemical conversion. The solar radiation absorption capacity can be increased by 7.05 %. The improvements reach a maximum efficiency of 3.17 % for photo-thermal conversion and 9.77 % for photo-chemical conversion. The excellent synergistic conversion of solar-to-fuel opens a new pathway towards accelerating energy transition and upgrading.

Modelling runoff components and hydrological processes in glaciated catchments of the inner Tien-Shan, Kyrgyzstan

Accurately quantifying runoff sources and understanding hydrological processes in glaciated mountain basins is essential for effective water resource management in the face of climate change. This study aimed to determine the contributions from various runoff sources in glaciated basins within the inner Tien-Shan mountains of Kyrgyzstan by utilizing integrated land surface, glacier energy-mass balance, and river routing models. To account for local topographic influences on solar radiation and cloud transmissivity processes, gridded meteorological forcing data were downscaled. The integrated models were then evaluated against observed discharge, glacier mass balance, and snow water equivalent, with a focus on the Kara-Batkak glacier reference site. Shortwave radiation correction was particularly important for improving the accuracy of model simulations. The results indicate that the peak glacier melt contribution occurs in July and August, with some basins reaching up to 54%. On an annual basis, the average contribution from glaciers across the basins was found to be 19%, while the ratios of snowmelt and rainfall were 58% and 23%, respectively. This study highlights the utility of integrated modelling approaches in understanding and quantifying runoff components in data-scarce high mountain regions. The incorporation of observed glacier data proved to be crucial for accurately representing hydrological processes under current climatic conditions. These findings underscore the significance of considering glacier dynamics and their influence on water resources to inform effective water management strategies in glaciated mountain basins.

Non-contact, portable, and stand-off infrared thermal imager for security scanning applications

In this article, we demonstrated the physical application of a portable infrared (IR) security scanning system for the non-contact and stand-off detection of target objects concealed underneath clothing. Such a system combines IR imaging and transfer learning with convolutional neural networks (CNNs) to enhance the detection of weak thermal signals and automate the classification of IR images. A mid-wavelength IR detector was used to record the real-time heat emitted from the clothing surface by human subjects. Concealed objects reduce the transmissivity of IR radiation from the body to the clothing surface, generally showing lower IR intensity compared to regions without objects. Due to limited resources for training data, the transfer learning approach was applied by fine-tuning a pre-trained CNN ResNet-50 model using the ImageNet database. Two image types were investigated here, i.e., raw thermal and Fuzzy-c clustered images. Receiver operating characteristic curves were built using a holdout set, showing an area-under-the-curve of 0.8934 and 0.9681 for the raw and Fuzzy-c clustered image models, respectively. The gradient-weighted class activation mapping visualization method was used to improve target identification, showing an accurate prediction of the object area. It was also found that complex clothing, such as those composed of materials of different transmissivity, could mislead the model in classification. The proposed IR-based detector has shown potential as a non-contact, stand-off security scanning system that can be deployed in diverse locations and ensure the safety of civilians.

All-Metal Evanescent Wave Filtenna With Small Frequency Ratio Between Radiation Null and Transmission Pole for Narrow-Band Diplex Applications

All-Metal Evanescent Wave Filtenna With Small Frequency Ratio Between Radiation Null and Transmission Pole for Narrow-Band Diplex Applications

Investigating the Dosimetric Leaf Gap Correction Factor of Mobius3D Dose Calculation for Volumetric-modulated Arc Radiotherapy Plans.

The dosimetric leaf gap (DLG) is a parameter for correcting radiation transmission through the round leaf end of multileaf collimators. The purpose of this study was to determine and investigate the optimal DLG correction factor for 6 MV volumetric-modulated arc radiotherapy (VMAT) plan dose calculations in Mobius3D. Seventeen VMAT plans were selected for the DLG correction factor optimization process. The optimal DLG correction factor was defined as the minimum difference between the measured dose and the Mobius3D-calculated dose on the Mobius Verification Phantom™ with different DLG correction factors. Subsequently, the optimal DLG correction factor was applied for Mobius3D dose calculation, and accuracy was assessed by comparing the measured and calculated doses. For verification and validation, the 17 previous plans and 10 newly selected plans underwent Mobius3D calculations with the optimal DLG correction factor, and gamma analysis was performed to compare them to the treatment planning system (TPS). Gamma analysis was also performed between the electronic portal imaging device (EPID) and the TPS for cross-comparison between systems. The DLG correction factor was optimized to -1.252, which reduced the average percentage differences between measured and Mobius3D-calculated doses from 2.23% ±1.21% to 0.03% ±1.82%. The cross-comparison between Mobius3D/TPS and EPID/TPS revealed a similar trend in gamma passing rate (>95%) in both the verification and validation plans. The DLG correction factor strongly influences the accuracy of Mobius3D-calculated doses. Applying the optimal DLG correction factor can increase dose agreement and gamma passing rate between calculation and delivered doses of VMAT plans, which emphasizes the importance of optimizing this factor during the commissioning process.

INFLUENCE OF ATMOSPHERIC AEROSOLS ON THE AMOUNT OF SOLAR ENERGY REACHING THE EARTH’S SURFACE IN THE SOUTHERN PART OF WARSAW

The efficiency of photovoltaic installations depends on a number of factors. Aerosols cansignificantly influence the available resources of solar energy and thus the effectiveness of solarpanel performance. The work was an attempt to assess the influence of atmospheric aerosols onthe transmission of solar radiation in a selected region of Warsaw. The results of measurementsof specific meteorological elements and the concentration of contaminants come from themeteorological station of the Warsaw University of Life Sciences in the years 2014-2019. Theanalysis of correlation and the MLP model path were used to carry out the analysis. The obtainedresults and relationships show that there is an influence of air contaminant concentrations onthe intensity of solar radiation and insolation. High variability of the given parameters was alsorevealed, depending on the range of horizontal visibility as well as relative air humidity. The valueof the correlation coefficient r=0.80 and comparison of the intensity of measured and predictedsolar radiation of the analysed parameters make it possible to claim that the developed MLP modelfacilitates good prediction of the intensity of solar radiation based on the implemented inputdata. The analysis of the sensitivity of the model revealed that the air temperature has the greatestinfluence on the value of solar radiation intensity, and as far as air contaminants are concerned, theconcentration of particulate matter PM10 has a greatest influence on lowering its value.

Shielding optimization to reduce the radiation field in the accelerator systems of IFMIF-DONES

In IFMIF-DONES, a deuteron beam will impinge on a flowing liquid lithium target, resulting in an intense neutron source. Other radiation sources will also arise due to the interactions between deuterons and the beam facing accelerator components. These radiation fields may cause some negative effects, such as damage to equipment or the generation of residual radiation sources. The characterization and mitigation of all the radiation sources are crucial for a safe operation and maintenance of the facility. In this study, the optimization and/or implementation of some radiation shields located in critical areas is considered to reduce the doses during operation and shutdown. Three scenarios are assessed: (i) shielding optimization of the High-Power Beam Dump for the accelerator commissioning, (ii) shielding optimization for the scraper of the High Energy Beam Transport line and the Fast Safety Isolation Valves, and (iii) shielding implementation to reduce the radiation transmission through Heating, Ventilation, and Air Conditioning wall penetrations. Radiation maps of the biological dose and the dose to silicon are computed, showing the impact of such shielding elements.

MICROWAVE ABSORBERS BASED ON MÖBIUS STRIP RESONATORS

The paper deals with technology of manufacturing of microwave absorbers with ordered and structured surface layer. This layer contains Möbius strip resonators, located on the fixed distance from each other. The technology was developed by the authors on the base of the following data: 1) results of theoretical study of microwaves interaction with Möbius strip resonator; 2) results of experimental study of electromagnetic radiation reflection, transmission and absorption coefficients in the microwave frequency range of the experimental samples of microwave absorbers based on Möbius strip resonators, which differ by the distance between these resonators. It was established on the base to the listed results that the microwave absorbers manufactured in accordance to the technology proposed by the authors are wide-band ones. Electromagnetic radiation absorption coefficient values of these absorbers changes from 0.5 to 0.97 in frequency range 2.0–17.0 GHz if the distance between the Möbius strip resonators containing in their surface layer, is 15.0 mm. If the distance between the Möbius strip resonators containing in the surface layer of the considered absorbers is less than 15.0 mm their electromagnetic radiation absorption coefficient in the indicated frequency bands is lower than presented values. The considered absorbers are promising for use in shielded rooms and anechoic chambers.

Multiple-pathways light modulation in Pleurosigma strigosum bi-raphid diatom.

Ordered, quasi-ordered, and even disordered nanostructures can be identified as constituent components of several protists, plants and animals, making possible an efficient manipulation of light for intra- and inter- species communication, camouflage, or for the enhancement of primary production. Diatoms are ubiquitous unicellular microalgae inhabiting all the aquatic environments on Earth. They developed, through tens of millions of years of evolution, ultrastructured silica cell walls, the frustules, able to handle optical radiation through multiple diffractive, refractive, and wave-guiding processes, possibly at the basis of their high photosynthetic efficiency. In this study, we employed a range of imaging, spectroscopic and numerical techniques (including transmission imaging, digital holography, photoluminescence spectroscopy, and numerical simulations based on wide-angle beam propagation method) to identify and describe different mechanisms by which Pleurosigma strigosum frustules can modulate optical radiation of different spectral content. Finally, we correlated the optical response of the frustule to the interaction with light in living, individual cells within their aquatic environment following various irradiation treatments. The obtained results demonstrate the favorable transmission of photosynthetic active radiation inside the cell compared to potentially detrimental ultraviolet radiation.

Studs' impact on sound transmission in double-leaf partitions

Double-leaf partitions constructed by two parallel plasterboard panels installed on steel studs are widely used in building constructions. Although it is known that the studs significantly influence vibroacoustic behavior of the plates, there has not been extensive research on this topic. This study focuses on the impact of steel studs on the sound transmission in double-leaf constructions. In order to fully analyze the impact of the steel stud element, a comparison between experimental data from a double leaf partition with a mechanical connection using steel studs and a theoretical model that disregards any mechanical connection between the parallel plasterboard panels was conducted. Results presenting radiation efficiency, transmission loss, and velocity level differences in a grid of points equally distributed on the radiating side of a structure highlight the influence of steel studs in double-leaf constructions indicating frequency ranges, where the studs’ impact is mostly significant.

Ultrathin SiO2 aerogel papers with hierarchical scale enable high-temperature thermal insulation

Aerogel composites reinforced by fibers have found extensive applications in the field of thermal insulation and energy conservation. However, the composites are hindered by their high infrared radiation transmittance and weak interface adhesion in practical applications. Herein, we designed and prepared a novel thin composite called ‘fiber/whisker/aerogel paper’ (SWAP) with a thickness of less than 1 mm. The SWAP integrated SiC nanowhiskers (SiCnw) as opacifiers and ultrafine SiO2 fibers as reinforcement, fabricated through wet manufacturing and sol-gel process. The ‘fiber/aerogel paper’ (SAP) and SWAP exhibited low thermal conductivity at room temperature, measuring 0.025 W/(m·K) and 0.033 W/(m·K), respectively. Additionally, they exhibited low densities of 0.195 g/cm3 and 0.225 g/cm3, respectively. Notably, SWAP exhibited excellent high-temperature insulation performance, primarily due to its low infrared transmittance (50% at 3 μm). The incorporation of SiCnw and ultrafine SiO2 fibers collectively enhanced the interfacial adhesion with the aerogel matrix even amidst rigorous testing (weight loss less than 3%). SWAP also demonstrated flexibility, high thermal stability, hydrophobicity, and flame resistance. Furthermore, a comprehensive investigation into the performance variations and influencing g factors of the material was conducted under different heat treatment conditions. This research provides guidance for the application of such materials under high temperatures.