Radiation Characteristics Research Articles

Topological traveling-wave radiation based on chiral edge states in photonic Chern insulators

Topological chiral edge states in photonic Chern insulators, which exhibit the one-way propagation property with reflection-free behavior and excellent robustness against perturbations, have become an important frontier in topological photonics. Currently, there have been many studies on its robust propagation behavior, but few studies have focused on its radiation properties. In developing functional photonic devices (e.g., topological antennas) for real-world applications, studying traveling-wave radiation characteristics based on chiral edge states deserves more attention. In this Letter, we propose a topological traveling-wave radiation system based on chiral edge states in photonic Chern insulators that show a steerable beam and reflection-free property. By introducing the perturbation controlled by magnetic fields, we demonstrate that exploiting a certain strength of perturbation can flexibly manipulate the radiation beam. In particular, the proposed dual-channel topological traveling-wave radiation system can not only improve the gain but also overcome the issue of impedance matching. The proposed configurations provide a novel way to manipulate topological-wave radiation and have potential applications for designing topological traveling-wave antennas with a reflection-free property.

A compact dual‐band omnidirectional antenna with folded microstrip lines and slotlines for 5G applications

AbstractA compact dual‐band omnidirectional antenna with folded microstrip lines and slotlines is proposed. The antenna is composed of a substrate and a superstrate. The superstrate is employed to broaden the antenna bandwidth. The radiating patch is situated on the upper surface of the substrate and consists of folded microstrip lines. The performance of the high‐frequency band can be optimized based on the analysis of the current distribution intensity. The bottom of the substrate is composed of a ground plane with slotlines. The introduction and improvement of the low‐frequency band are achieved by modifying the ground plane structure with characteristic modal analysis. The antenna demonstrates omnidirectional radiation characteristics across both frequency bands. The dimensions of the antenna are π × 0.178 λ0 × 0.178 λ0 × 0.049 λ0 (π × 22 × 22 × 6 mm). The antenna achieves a maximum gain of 3.37 dBi at 2.5 GHz and 2.74 dBi at 5.8 GHz. The measured impedance bandwidths for the two frequency bands are 17.3% and 21.7%, respectively.

Investigation of Radiation Exposure of Medical Staff During Lateral Fluoroscopy for Posterior Spinal Fusion Surgery

Background/Objectives: In spinal surgery, it is especially crucial to insert implants in the correct location. Intraoperative fluoroscopy is often necessary to safely perform spinal surgery because of serious complications that can occur if the screw deviates. However, the use of intraoperative fluoroscopy comes at the cost of radiation exposure to the surgeons and operating room staff. Therefore, it is desirable for spinal surgeons to understand the characteristics of radiation in order to minimize patient and medical staff exposure. This study aimed to create an aerial radiation dose distribution map for lateral fluoroscopy, a commonly used technique for posterior spinal fusion. Methods: A human body-equivalent phantom was placed in a prone position on the Jackson Table. The measurement method used was a lateral fluoroscopic evaluation, assuming posterior spinal fusion. Measurements were taken at three levels: 80 (gonadal), 100 (thoracoabdominal), and 150 cm (lens and thyroid). Results: The highest radiation doses were received by primary surgeons. The scrub nurse was the next most exposed. Conclusions: We developed an aerial dose distribution map for lateral fluoroscopy in posterior spinal fusion. Radiation exposure was the highest among primary surgeons.

Optimal Design of Smart Antenna Arrays for Beamforming, Direction Finding, and Null Placement Using the Soft Computing Method

ABSTRACTThe urge of modern communication system is to design and development of the smart antennas with adaptive radiation characteristics. The multifold capabilities of fourth‐dimensional antenna arrays can cater that much needed adaptiveness if properly designed. Compared to the conventional arrays, the fourth‐dimensional arrays have one added advantage as the ‘Time’ of all the switched‐on antenna elements can be managed to generate the required amplitude and phase tapering without even using attenuators and phase shifters. However, one inherent limitation of fourth‐dimensional control parameter is the generation of harmonics or sidebands. This article proposes various means of radiation pattern synthesis in fourth‐dimensional linear antenna arrays with pulse shifting, pulse splitting, and a combination of both. First of all, the pulse splitting and shifting techniques are combinedly proposed by reducing the sidelobe levels and sideband levels of the beamforming antenna arrays to enhance directivities and efficiencies. Then, this mathematical proposition of the direction finding fourth‐dimensional arrays is developed. Finally, broad nulls over a specific angle of arrival region are created for jamming and interference mitigation. For all these cases, the sidelobe level and the unwanted higher‐order sideband levels are suppressed to reduce the unwanted interferences and power losses. The optimal time schemes for all the synthesized patterns are generated by proposing a chaos‐based soft computing algorithm. The radiofrequency signals at each radiating array element are processed by the optimal time schemes proposed for specific applications. The outcomes are validated and compared with other state‐of‐the‐art works of this domain to prove the competency of the proposed work. The qualitative and quantitative comparisons presented for beamforming array is aimed for a good improvement over other reported works by targeting ultralow (less than −40 dB) sidelobe and sideband levels. For direction‐finding array, the proposed idea has also targeted ultralow sidelobes for the main as well as steered beam patterns. Furthermore, the null placement over a region has been aimed to cover more area for jamming and sidelobe reduction for interference mitigation. Overall, the optimal designs proposed for these advanced applications are beneficial for cutting‐edge communication systems.

Flame temperature and emissivity distribution measurement of solid propellant based on clustering analysis of multispectral radiation images

To measure the combustion parameters of a solid propellant, this Letter researches the fitting method for flame temperature and emissivity based on multispectral images and proposes the particle swarm optimization–K-means (PSO–K-means) clustering optimization algorithm of a flame multispectral image. Considering the difference in flame radiation characteristics in different regions, the flame multispectral image is clustered, and spectra in different regions are analyzed and selected in different fitting bands to inverse temperature and emissivity. On this basis, the method is applied to measure solid propellant combustion parameters with different formulations. The measurement shows that the flame temperature is between 1700 and 2100 K, and the emissivity is concentrated in 0.1–0.5. Compared with temperature measurements obtained from tungsten–rhenium thermocouples, the relative deviation of multispectral imaging thermometry is less than 5%. The distribution characteristics of solid propellant combustion parameters with different formulations were analyzed, which provided important data support for evaluating combustion conditions and optimizing solid propellant formulations.

Dy3+ ions in fluorophosphate glasses for luminescent white light applications

Abstract In this study, a series of fluorophosphate (FP) glasses, activated with Dy3+ ions and displaying concentration dependence, have been prepared and analyzed for their suitability in luminescent white light applications. The melt quenching method was utilized to fabricate a set of FP glasses, doped with Dy3+ ions and possessing the composition of (60-x) P2O5+10MgO+10ZnO+10BiF3+10KF+xDy2O3, where x ranges from 0.1 to 2.0 mol%. The structural properties of the samples were analysed using X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR), and Raman spectroscopy while the optical properties of the samples were studied using absorption and emission spectra. The amorphous nature of the FP glasses was confirmed through SEM analysis and XRD profiles. Moreover, the presence of elements in their composition was verified using EDX. The FTIR spectra of the FP glasses exhibited vibration bands consistent with the characteristic phosphate groups, which was further supported by Raman analysis. The absorption spectra were used to calculate oscillator strengths (fexp & fcal) and Judd-Ofelt parameters Ωλ (λ=2, 4, 6). The values of Ωλ (λ=2, 4, 6) followed this order: Ω6>Ω2>Ω4. The emission spectra displayed three prominent transitions in the UV-visible region: (4F9/2→ 6H15/2) blue, (4F9/2→ 6H13/2) yellow, and (4F9/2→ 6H11/2) red. The peak at 553 nm (4F9/2→ 6H13/2) was the most intense and dominant. Radiative characteristics were evaluated from the emission spectra through the employment of J-O intensity parameters and refractive indices. The Y/B intensity ratio values were greater than 1, indicating the high covalency of Dy3+ ions. The color coordinates (x, y) and correlated color temperature values of CIE 1931 were situated in the cool white region. The comprehensive analysis suggests that these glasses have the potential to become highly favorable candidates as luminescent components for solid-state white light emitting instruments.

Design of dual-band filtering patch antenna based on SIR multimode resonator

Abstract With the development of the communication field, more and more communication devices need multiple single-frequency antennas to work simultaneously. However, using multiple single-frequency antennas results in larger sizes. The miniaturized and dual-band communication system has become a new development trend. This paper designs a dual-band filtering patch antenna based on a multimode resonator, which is cascaded. The filter resonator part adopts step impedance resonance for branch shunt design, which can flexibly control the center frequency of two frequency bands. The filtering antenna utilizes a dual-layer substrate structure and achieves an integrated design through coupling probe feeding. This reduces the horizontal dimensions and improves miniaturization. Multiple radiation nulls are introduced outside the two-passband, and roll-off characteristics are evident. In addition, this design realizes high selectivity in the operating band. The antenna has large gains of 1.71 dBi and 6.25 dBi. It has good filtering and radiation characteristics.

Study on radiation characteristics of multi-phase plumes containing ice crystals in orbit-control engines

In order to obtain the radiation characteristics of the multiphase plume containing ice crystals in the high-altitude orbit control engine and analyze its influence on the telemetry effect, this paper deduces the radiation characteristics parameters of gases based on Einstein radiation theory and radiation transfer equation. Based on the latest HITRAN2020 spectral line library solving gas radiation and the Mie theory of particle scattering solving particle radiation, the radiation characteristic parameters of the multi-phase plume containing ice crystals in the high-altitude orbital control engine and the radiation intensity distribution in the near-infrared and mid-long wave infrared bands are simulated, and the main influencing factors of the radiation are analyzed. The results show that, in general, the main radiation of the engine plume includes the scattered light in the near infrared band and the thermal radiation in the middle long wave infrared band. In the near-infrared band, considering solar background radiation, the total radiation amount in the calculation domain is about 10 −6 W/sr, and the thermal radiation is dominant within the axial distance of 0.5 m, while the ice crystal scattering is dominant beyond the axial distance of 0.5 m . In the mid-long wave infrared band, the total radiation amount in the calculation domain is about 10 W/sr, and the thermal radiation of gas dominates within 1 m axial distance, while the thermal radiation of ice crystal dominates beyond 1 m axial distance.

High-throughput, low-cost FLASH: irradiation of Drosophila melanogaster with low-energy X-rays using time structures spanning conventional and ultrahigh dose rates.

FLASH radiotherapy is an emerging technique in radiation oncology that may improve clinical outcomes by reducing normal tissue toxicities. The physical radiation characteristics needed to induce the radiobiological benefits of FLASH are still an active area of investigation. To determine the dose rate, range of doses and delivery time structure necessary to trigger the FLASH effect, Drosophila melanogaster were exposed to ultrahigh dose rate (UHDR) or conventional radiotherapy dose rate (CONV) 120-kVp X-rays. A conventional X-ray tube outfitted with a shutter system was used to deliver 17- to 44-Gy doses to third-instar D. melanogaster larvae at both UHDR (210Gy/s) and CONV (0.2-0.4Gy/s) dose rates. The larvae were then tracked through development to adulthood and scored for eclosion and lifespan. Larvae exposed to UHDR eclosed at higher rates and had longer median survival as adults compared to those treated with CONV at the same doses. Eclosion rates at 24Gy were 68% higher for the UHDR group (P<0.05). Median survival from 22Gy was >22days for UHDR and 17days for CONV (P<0.01). Two normal tissue-sparing effects were observed for D. melanogaster irradiated with UHDR 120-kVp X-rays. The effects appeared only at intermediate doses and may be useful in establishing the dose range over which the benefits of FLASH can be obtained. This work also demonstrates the usefulness of a high-throughput fruit fly model and a low-cost X-ray tube system for radiobiological FLASH research.

Research on Through-Flame Imaging Using Mid-Wave Infrared Camera Based on Flame Filter.

High-temperature furnaces and coal-fired boilers are widely employed in the petrochemical and metal-smelting sectors. Over time, the deterioration, corrosion, and wear of pipelines can lead to equipment malfunctions and safety incidents. Nevertheless, effective real-time monitoring of equipment conditions remains insufficient, primarily due to the interference caused by flames generated from fuel combustion. To address this issue, in this study, a through-flame infrared imager is developed based on the mid-wave infrared (MWIR) radiation characteristics of the flame. The imager incorporates a narrowband filter that operates within the wavelength range of 3.80 μm to 4.05 μm, which is integrated into conventional thermal imagers to perform flame filtering. This configuration enables the radiation from the background to pass through the flame and reach the detector, thereby allowing the infrared imager to visualize objects obscured by the flame and measure their temperatures directly. Our experimental findings indicate that the imager is capable of through-flame imaging; specifically, when the temperature of the target exceeds 50 °C, the imager can effectively penetrate the outer flame of an alcohol lamp and distinctly capture the target's outline. Importantly, as the temperature of the target increases, the clarity of the target's contour in the images improves. The MWIR through-flame imager presents considerable potential for the real-time monitoring and preventive maintenance of high-temperature furnaces and similar equipment, such as detecting the degradation of refractory materials and damage to pipelines.

Mission-Based Design and Retrofit for Energy/Propulsion Systems of Solar-Powered UAVs: Integrating Propeller Slipstream Effects

Over twenty Solar-Powered Unmanned Aerial Vehicle (SPUAV) designs exist worldwide, yet few have successfully achieved uninterrupted high-altitude flight. This shortfall is attributed to several factors that cause the actual performance of SPUAV to fall short of expectations. Existing studies identify the propeller slipstream as one of these adverse factors, which leads to a decrease in the lift–drag ratio and an increase in energy consumption. However, traditional design methods for SPUAVs tend to ignore the potential adverse effects of slipstream at the top-level design phase. We find that this oversight results in a reduction in the feasible mission region of SPUAVs from 109 days to only 46 days. To address this issue, this paper presents a high-fidelity multidisciplinary design framework for the energy/propulsion systems of SPUAVs that integrates the effects of a propeller slipstream. Specifically, deep neural networks are employed to predict the lift–drag characteristics of SPUAVs under various slipstream conditions, and the energy performance is further analyzed by evaluating the time-varying state parameters throughout a day. Subsequently, the optimal solutions for the energy/propulsion systems specific to certain latitudes and dates are obtained through optimization design. The effectiveness of the proposed design framework was demonstrated on a 30-m wingspan SPUAV. The results indicated that, compared to the traditional design method, the proposed approach led to designs that more effectively accomplished closed-loop flight in designated regions and prevented the reduction of the feasible mission region. Additionally, through the targeted retrofit of the energy/propulsion systems, SPUAVs exhibited enhanced adaptability to the solar radiation characteristics of different mission points, resulting in a further expansion of the feasible mission region. Furthermore, this research also explored the variation trends in optimal solutions across different latitudes and dates and investigated the reasons and physical mechanisms behind these variations.

Nanocomposite Embedded Electric and Magnetic Material Enhancing Antenna Radiation by Linear Relation in Radiators

The main and auxiliary radiating elements are linked by linear mathematical relation and coated with nanocomposite (NC) materials to enhance radiation characteristics. Nanocomposite-based electric material (NE) and nanocomposite-based magnetic material (NM) coated on auxiliary radiating elements to enhance the electromagnetic radiation of the proposed antenna. The radiating elements coated with NE graphene oxide (GO) and NM barium ferrite (BF) have higher electric field and magnetic field distribution respectively. The linear relation of main and auxiliary elements is verified by two substrates FR4, Teflon with correlated results. This proposed NC-coated antenna produces a bandwidth of 4.15 GHz, 4.02 dBi average gain and radiation efficiency of 95.17%, being superior to the antenna without NC coating. Fabricated antenna has 1.56–5.71 GHz bandwidth that includes 2.4/5.2 GHz WLAN, 2.5/3.5 GHz WiMAX, 2.4 GHz ISM, 5G SUB-6 GHz, 5G NR 78 and 2.4/5 GHz Wi-Fi bands.

First experimental confirmation of island SOL geometry effects in a high radiation regime on W7-X

Abstract This work characterizes the detachment behavior and radiation characteristics of the low&amp;#xD;iota configuration in the Wendelstein 7-X (W7-X) stellarator. The island scrape-off layer (SOL) of the&amp;#xD;low iota has a poloidal mode number of 6 islands surrounding the last closed flux surface (LCFS).&amp;#xD;The island geometry of the low iota configuration is significantly different to that of the standard&amp;#xD;magnetic field configuration, whose detachment characteristics have already been described in previous&amp;#xD;work[2, 3, 4]. Experimental results show that the radiation pattern in the low iota configuration&amp;#xD;is starkly different to that of the standard magnetic field configuration, with radiation concentrated&amp;#xD;at the island SOL O-points, rather than the X-points. Additionally, this O-point localized radiation&amp;#xD;pattern is associated with unstable detachment, with both radiation oscillations in experiments and the&amp;#xD;lack of a self-consistent plasma solution at high radiated power fraction in EMC3-Eirene simulations.&amp;#xD;EMC3-Eirene simulations are used to understand the radiation distribution. It was found that the O-&amp;#xD;point localized radiation arises first from local impurity accumulation near the parallel flow stagnation,&amp;#xD;which is located close to the geometrical center of the island (”O-point”). The local cooling in this&amp;#xD;region leads to plasma condensation in the islands in closest magnetic connection to the divertor target&amp;#xD;plates. The heat source to this region of the island, which is thermally isolated from the upstream heat&amp;#xD;source in terms of parallel transport, must arise via perpendicular heat transport. This heat source is&amp;#xD;expected to be large for the low iota configuration due to its very small internal island field line pitch.&amp;#xD;This work highlights the importance (complementary to previous work, e. g. [5, 6]) of the internal&amp;#xD;island field line pitch not only on the radiation pattern, but also the detachment performance of the&amp;#xD;island divertor.

Bifocal system of two reflect arrays

A technique has been developed for accurately solving the problem of geometric-optical synthesis of a bifocal system of two flat reflect arrays, based on the sequential determination of the distribution of the eikonal introduced by different sections of the arrays, with its assignment at the initial section of one of the arrays, while the introduced eikonal at the initial section of the other array is found as a result of synthesis of the output flat front for the central position of the feed. The technique ensures the continuity of functions describing the distributions of introduced eikonals, as well as their first and second derivatives (along one coordinate) at the boundaries of sections. The dependence of the value of the mean square eikonal aberration at the system output on the arrays parameters has been studied. As an example of the application of the developed technique, the bifocal systems for visual angles of 40°and 65°were synthesized and optimized. A study of the radiation characteristics of an antenna based on synthesized and optimized bifocal systems was carried out.

Infrared and Visible Image Fusion via Sparse Representation and Guided Filtering in Laplacian Pyramid Domain

The fusion of infrared and visible images together can fully leverage the respective advantages of each, providing a more comprehensive and richer set of information. This is applicable in various fields such as military surveillance, night navigation, environmental monitoring, etc. In this paper, a novel infrared and visible image fusion method based on sparse representation and guided filtering in Laplacian pyramid (LP) domain is introduced. The source images are decomposed into low- and high-frequency bands by the LP, respectively. Sparse representation has achieved significant effectiveness in image fusion, and it is used to process the low-frequency band; the guided filtering has excellent edge-preserving effects and can effectively maintain the spatial continuity of the high-frequency band. Therefore, guided filtering combined with the weighted sum of eight-neighborhood-based modified Laplacian (WSEML) is used to process high-frequency bands. Finally, the inverse LP transform is used to reconstruct the fused image. We conducted simulation experiments on the publicly available TNO dataset to validate the superiority of our proposed algorithm in fusing infrared and visible images. Our algorithm preserves both the thermal radiation characteristics of the infrared image and the detailed features of the visible image.

Electromagnetic scattering of a 3D spherical impedance cavity with a circular aperture by an arbitrarily located and oriented Hertzian dipole

The problem of the scattering of an arbitrarily oriented and located Hertzian dipole from an impedance cavity with a circular aperture satisfying different impedance values at inner and outer spherical surfaces is solved with a method of auxiliary sources (MAS). The study of that canonical problem with Leontovich boundary conditions answers the effects of the location of the excitation, aperture size, and boundary conditions on the resonance and radiation characteristics of the semi-opened spherical cavity. The proposed approach employs the distribution of the two perpendicular Hertzian dipoles on auxiliary surfaces representing the scattered field inside and outside the spherical cavity with a circular aperture. As the numerical results, the total radar cross section and the near field distributions are provided for different cases including the aperture size, source location, and boundary conditions. The resonance characteristics are analyzed. The method is validated by other approaches for the limit cases.

Assessment of Wind Energy Potential and Optimal Site Selection for Wind Energy Plant Installations in Igdir/Turkey

Wind energy is an eco-friendly, renewable, domestic, and infinite resource. These factors render the construction of wind turbines appealing to nations, prompting numerous governments to implement incentives to augment their installed capacity of wind turbines. Alongside augmenting the installed capacity of wind turbines, identifying suitable locations for their installation is crucial for optimizing turbine performance. This study aims to evaluate potential sites for wind power plant installation via a GIS, a mapping technique. The Analytic Hierarchy Process (AHP) was employed to assess the locations, including both quantitative and qualitative aspects that significantly impact the wind farm suitability map. Utilizing the GIS methodology, all datasets were examined through height and raster transformations of land surface temperature, plant density index, air pressure, humidity, wind speed, air temperature, land cover, solar radiation, aspect, slope, and topographical characteristics, resulting in the creation of a wind farm map. The correlation between the five-year meteorological data and environmental parameters (wind direction, daily wind speed, daily maximum and minimum air temperatures, daily relative humidity, daily average air temperature, solar radiation duration, daily cloud cover, air humidity, and air pressure) influencing the wind power plant in Iğdır province, including Iğdır Airport, Karakoyunlu, Aralık, and Tuzluca districts, was analyzed. If wind energy towers are installed at 1 km intervals across an area of roughly 858,180 hectares in Igdir province, an estimated 858,180 GWh of wind energy can be generated. The GIS-derived wind power plant map indicates that the installation sites for wind power plants are located in regions susceptible to wind erosion.

Experimental study on radiational characteristics and nursing care of a novel radioisotope 188Re memory alloy esophageal stent.

Radioactive esophageal stent, known for inhibiting tumor growth and delaying restenosis in malignant esophageal tumors, presents challenges due to potent radiation, leading to side effects. This study aims to support the clinical use of 188Re radioactive esophageal stent. The 188Re stent with 128MBq initial activity was placed in a biomimetic esophageal membrane. Radiation absorption doses were measured by thermoluminescence and calculated using mathematical software. Under simulated positioning, the stent was implanted in the esophagus of an experimental pig, followed by the feeding of Kangfuxin solution and nursing care (KFX-RT). Non-implanted and implanted-only pigs served as normal (CR) and experimental (RT) controls. Blood samples collected on days 7 and 21 were analyzed for inflammatory factors (TGF-β1, TNF-α, IL-6) using enzyme-linked immunosorbent assay. Esophageal tissue cells were assessed for deoxyribonucleic acid index (DI) and subdiploid content through flow cytometry. Absorbed doses at 0.5mm and 5mm reference points were 223.91cGy and 20.55cGy, respectively, with 92.64% absorbed within a 1mm thickness. Radiation dose significantly decreased at 6.5mm, with only 4.72% absorbed at depths ≥6.5mm. On days 7 and 21, levels of inflammatory factors, DI and subdiploid content were significantly increased in the KFX-RT and RT groups compared to the CR group, while all levels in the KFX-RT group were significantly lower than in the RT group. The 188Re esophageal stent exhibits high radiation absorption in superficial tissues and low absorption in deeper tissues. Kangfuxin solution combined with nursing care alleviates radiation-induced inflammatory damage.

Acoustic radiation characteristics of shark skin inspired surface modified plates

This paper aims to evaluate the acoustic radiation characteristics of thin plates featuring a layer of small-scale biomimetic shark skin type additive surface treatment. The shark skin dermal denticles are modelled as point masses arranged in a bi-directional pattern on both the upper and lower surfaces of the plate. The governing equations are obtained through a variational approach, incorporating the Dirac Delta function in the derivation of the proposed semi-analytical model for the shark skin layer. A semi-analytical method based on the Rayleigh–Ritz formulation is utilized to analyze the vibrations of these plates with surface modification. The sound radiation characteristics are then derived from the solution of the Rayleigh integral. A comprehensive investigation is performed on the influence of surface modification on different vibro-acoustic characteristics, using a continuous structural mode and power transfer matrix-based approach. Notable observations include a reduction in peak vibro-acoustic responses with dense denticle arrangements, especially at resonance, demonstrating a direct relationship with mass ratios, i.e., the ratio of denticle mass to plate mass. The study further reveals a shift of vibro-acoustic responses towards low frequencies with an increase in mass ratios. A thorough comparative study indicates that while additive surface modifications inspired by shark skin may weaken sound radiation characteristics at resonance frequencies, a reverse effect can be observed at intermittent operational frequencies.

Quantifying the effects of spectral and directional distribution of radiation on its propagation in saline water

The interactions of radiation with saline water facilitate various energy-related applications, such as radiative evaporation at the air–water interface, radiation-driven underwater vapor generation, and underwater photovoltaic systems. However, these applications require a comprehensive understanding of radiation propagation through saline water, considering both its spectral and directional characteristics, which are often inadequately explored. This study introduces a three-dimensional Monte Carlo radiative transfer model equipped with fine spectral resolution and detailed angular considerations. The model simulates the transfer of radiation from the air to the air–water interface and throughout the saline water body to thoroughly examine the effects of spectral and directional properties of incident radiation on its propagation across different depths of saline water. The findings reveal that within the solar spectrum, radiation entering the water at a 62.7-degree angle of incidence and completely diffuse radiation exhibit similar absorption effects in water layers less than 2 meters deep. In addition, the incident angle has little impact on the absorption rate of both the water surface and the water body when the angle is below 62.7°. Spectrally, radiation wavelengths longer than 1.4μm, 1.14μm, and 1μm are fully absorbed within the first 1, 8, and 50 centimeters of saline water, respectively, representing approximately 20%, 30%, and 50% of incident solar radiation. Additionally, radiation from blackbody sources below 1300 Kelvin is absorbed entirely within the top 1 centimeter of saline water. Empirical correlations are then developed to easily estimate the absorption rate based on the depth of the water and the temperature of the blackbody heat source. The findings elucidate the influence of the spectral and directional characteristics of incident radiation on its underwater propagation, offering essential guidance for the design and performance evaluation of various energy-centric applications.