A compact Triple Circular Ring (TCR) metamaterial absorber with dimensions of 6 & times; 6 mm2 is proposed. It offers dual-band operation with high absorption and superior shielding effectiveness. The proposed structure achieves high absorption peaks at 10.94 GHz and 15.55 GHz with the absorption rate of 99.6% and 99.89%. It exhibits maximum shielding effectiveness at 14.84 GHz and 28.07 GHz with magnitudes of-55.72 dB and-40.6 dB, respectively. This difference arises because shielding effectiveness accounts for both absorption and reflection, enabling strong electromagnetic blocking even without peak absorption. The bandwidths of the absorber is 1.4 GHz and 2.94 GHz, respectively. The moisture sensitivity of the sensor is 19.35 GHz/RIU. This highlights strong potential for precise moisture detection. The design demonstrates polarization stability for orthogonal transverse electric (TE) and transverse magnetic (TM) modes and maintains angular stability for oblique incidences up to 75 degrees with minimal degradation. The absorber is well-suited for electromagnetic interference suppression in compact high-frequency devices and moisture sensing.

This paper presents the design and optimization of a high-performance nano-rectenna for harvesting solar energy via a metamaterial geometry. This is achieved with the design of an optimized unit cell, namely, a quadruple cut cylindrical resonator (QCCR), intended for broadband absorption ranging from ultraviolet to infrared frequencies. Numerical simulation and electromagnetic analysis were done to study how geometric changes in the QCCR affect absorption, resonance, and overall energy conversion efficiency. The optimized QCCR structure achieves up to 90

The Electron Emission Coefficient (EEC) is a critical parameter in atomic and nuclear detectors. This study investigates the impact of the spallation process and metamaterial coatings (Graphene/hBN and Graphene/WC) on EEC under 30, 500, and 1000 MeV proton irradiation using the MCNPX code. Results indicate that both the spallation process, which produces a discrete particle spectrum, and the application of metamaterial layers significantly enhance EEC. When considering spallation with a 0.1 mm Graphene/WC coating, EEC increased by 122.36%, 49.15%, and 593.5% for silver, copper, and aluminum, respectively. Without the spallation process, these increases were 30.97%, 33.17%, and 196.61%. Specifically, incorporating the spallation phenomenon alongside Graphene/WC led to net EEC gains of 76.36% for silver, 27.84% for copper, and 22.86% for aluminum compared to baseline scenarios. Furthermore, Graphene/WC outperformed Graphene/hBN in increasing EEC across all electrodes by a factor ranging from 2.15 to 12.76. These findings demonstrate that combining Graphene/WC metamaterials with spallation effects offers a superior method for optimizing electron emission in electrode design.

Radiation hazards in natural environments are closely associated with the activity concentrations of naturally occurring radionuclides such as 232Th, 137Cs, 40K, and 238U. The sediments of the Garab Hot Spring in Behbahan, Iran, widely utilized for recreational and therapeutic purposes, were investigated to assess potential radiological risks. Sediment samples were systematically collected from four different locations: the spring source, the downstream channel, the bathing pool, and the surrounding soil. Activity concentrations of the radionuclides were measured, and key radiological hazard indices were computed, including the Raeq, D(center dot)r, (center dot)Dout, (center dot)Din, Dtot, Hex, Hin, I gamma, and ELCR. Results indicated that, while the concentrations of 40K and 238U remained below the international safety limits recommended by UNSCEAR (2000), elevated levels of 232Th and 137Cs were observed. The Raeq values ranged from 38.8 to 312.65 Bq/kg, remaining below the critical threshold of 370 Bq/kg. However, the ELCR values ranged from 1.80E-3 to 6.12E-3, exceeding the accepted limit of 1.78E-3. Furthermore, all dose rate indices (D(center dot)r, (center dot)Dout, (center dot)Din, Dtot), except for I gamma, Hex, and Hin, surpassed their permissible levels, indicating a notable radiological hazard. In addition, the presence of heavy metals was analysed using the PGNAA method with a 5 Ci Am-Be neutron source. Sensitivity analysis identified gamma energies of 465.3 key and 122.08 key as the most reliable markers for detecting lead (Pb) and iron (Fe), respectively. Overall, the findings suggest that prolonged exposure to sediments from the Garab Hot Spring may pose significant radiological health risks, particularly due to elevated thorium and cesium activities and the associated excess lifetime cancer risk. Caution is therefore advised regarding long-term recreational or therapeutic use of the site.

This manuscript demonstrates a new nanoscale metamaterial absorber (NMMA) based on simulation-driven design for maximizing the absorption of solar energy, from the infrared to ultraviolet regions. The design comprises square box and plus ring resonators interconnected with elliptic rods and made use of gold and nickel on a quartz substrate with a gold ground plane. The absorption of the NMMA is more than 95% at 633.20-816.80 THz and 1034.40-1401.60 THz, with an average value of 96.89%, which shows excellent absorption in the visible to partial ultraviolet regions. In addition, the absorption bandwidth from 422.40 to 1818.10 THz in the structure significantly covers infrared, visible and ultraviolet ranges with an average absorption of 88.49% and peak absorption 99.83% at 708.00 THz established for the whole range. This NMMA has very high absorption performance for the incident light of any polarization and an off-normal angle within 30 degrees, and is still highly efficient even after bending with an angle as large as 18 degrees. Material selection, physics of the geometric parameters and structural direction bending on the absorption, investigation of field distributions, surface currents, as well as power loss are also discussed. This kind of NMMA holds promising engineering prospects for infrared detection and solar energy utilization.

A metamaterial absorber is designed using a multiple split-ring structure that has symmetrical circular edge splits. The absorber is polarization-insensitive and shows peak of absorption in the quad-band. To support the design, an FR-4 substrate is used. The dimensions of the absorber are 0.119 λ by 0.119 λ. Results show an absorption rate above 99

This study presents a predictive framework for modeling the dispersion of radioactive materials following a hypothetical incident at the Zaporizhzhia Nuclear Power Plant. Leveraging meteorological data from the National Oceanic and Atmospheric Administration (NOAA) and simulations via the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, key environmental variables such as altitude, temperature, and humidity were forecasted for the period of February 1 to 7, 2024. These forecasts were extended using a Long Short-Term Memory (LSTM) neural network, enabling trajectory predictions for the following week, which were then compared against actual observations. To quantify the accuracy of the predictions, statistical indicators including Mean Absolute Error (MAE), Root Mean Square Error (RMSE), Mean Absolute Percentage Error (MAPE), Mean Relative Error (MRE), and Mean Bias Error (MBE) were applied. The LSTM network demonstrated superior precision in longitude estimation (MAE: 0.0837, RMSE: 0.1241, MAPE: 0.1779 %) compared to the Recurrent Neural Network (RNN), which showed higher error margins. Similarly, for latitude prediction, the LSTM model maintained lower deviation values (MAE: 0.2019, RMSE: 0.3845) than its RNN counterpart. These findings highlight the LSTM's advantage in handling long-term sequential data, particularly in scenarios where traditional RNNs struggle with vanishing gradients and loss of temporal dependencies. The proposed approach offers a reliable tool for enhancing nuclear emergency preparedness, supporting early warning systems, and informing strategic countermeasures in the face of radiological threats.

This study proposes a broadband metamaterial absorber for sensing chemical constituents in skincare products. The designed unit cell comprises a gold core and a polytetrafluoroethylene dielectric layer, with an overall dimension of 20 & micro;m & times; 20 & micro;m. The absorber exhibits a left-handed electromagnetic response, with 99.9% absorption at resonance frequencies and a bandwidth of 1.97 THz. The polarisation spectrum indicates stable performance from 0 degrees to 45 degrees. The absorber's surface current and impedance yield near-unity absorption at resonance frequencies, indicating good agreement. Most commonly used hydroquinone, ethanolamine, and parabens are selected as the chemical constituents for sensing applications. The permittivity of these chemicals, based on their terahertz dielectric properties, is determined using Lorentz dispersion parameters. The resonance frequency changed as the chemical concentration increased from 1% to 5%, yielding a maximum sensitivity of 2.12 THz/RIU, a quality factor up to 70.13, and a figure of merit of 25.36. Overall, the study highlighted that the uniquely designed metamaterial absorber can be used in terahertz chemical sensing for cosmetic safety monitoring.

This study investigates the efficacy of gallium as a contrast agent for enhancing X-ray phototherapy in breast cancer tumors using the MCNPX code. A tumor was simulated within the breast section of the Medical Internal Radiation Dose (MIRD) phantom and irradiated with a 100 key X-ray source. Gallium concentrations ranging from 1 % to 9 % (by weight) were introduced into the tumor volume to evaluate the enhancement of the deposited dose. Additionally, the reduction in scattered dose to nearby critical organs was assessed. The results indicate that increasing the gallium concentration significantly enhances the dose deposited in the tumor, reaching a saturation effect at higher percentages. Critically, the presence of 9 % gallium reduced the scattered dose to surrounding organs by a range of 62 %-93 %. This study demonstrates the potential of gallium-enhanced radiotherapy to simultaneously increase tumor dose while substantially protecting surrounding healthy tissues, thereby improving the therapeutic ratio.

Solar energy has emerged as one of the most scalable and sustainable solutions in a global landscape still dominated by fossil fuel-dependent economies. In particular, Concentrated Solar Power (CSP) is of interest due to its ability to provide dispatchable renewable energy in the form of a combined Thermal Energy Storage (TES) system, thus allowing stable support of the grid and delivery of power during peak hours. The situation in India reflects the stagnant deployment of CSP despite the high Direct Normal Irradiance (DNI) in several regions, especially Rajasthan and Gujarat, due to high capital costs, water scarcity, unpredictable bidding schemes, and limited domestic manufacturing capacity. This paper discusses global CSP trends and India’s technological advancements, policy development, cost-reduction measures, and water-efficient cooling solutions, as well as hybridization strategies such as coal-CSP and CSP-PV integration. The analysis recommends hybridization with existing fossil infrastructure, adoption of advanced molten salt and packed-bed thermal storage, and policy support, including tariff certainty, domestic manufacturing incentives, and grid-service payments as viable pathways for a CSP revival in India.

This study aims to simulate brain tissue and its elements using the MCNPX nuclear code and analyze X-ray emissions for tumor detection. This non-invasive approach offers a promising method for the accurate diagnosis of brain tumors, enabling timely treatment. Brain tissue, including tumor regions, was simulated at 70 keV, a common radiology energy. X-ray emissions were evaluated for variations in tissue density, elemental composition, thickness, and depth. The emitted X-ray doses were divided into 100 segments for detailed analysis. These data were then processed using an optimized Bi-LSTM neural network. This approach enabled precise segmentation and analysis of the X-ray data, improving tumor detection accuracy. Results showed significant differences in X-ray emission patterns between normal and tumor tissues. Tumor tissues exhibited distinct signatures, which were effectively captured and analyzed by the Bi-LSTM model. The model distinguished tissue types based on density, composition, thickness, and depth (1-5 cm). This study demonstrates that combining X-ray emission analysis with a Bi-LSTM neural network provides an effective method for brain tumor detection. The proposed approach may enhance non-invasive diagnostic capabilities and improve patient outcomes through early detection.

The protection of spacecraft, such as the International Space Station (ISS), from space radiation is essential to ensure the safety of both the crew and equipment. This study evaluates the shielding performance of two composite materials, jute/polyester and glass/polyester, against cosmic radiation, with a focus on their ability to mitigate high-energy particles. By investigating cosmic sources such as protons, neutrons, and gamma rays, the study analyzes the materials' effectiveness in reducing radiation exposure and their resistance to particle-induced spallation. Key findings highlight that both materials provide substantial shielding, with jute/polyester offering the added benefit of sustainability. The study also examines the formation of secondary particles and long-lived radionuclides generated during cosmic particle interactions. These results indicate that jute/polyester and glass/polyester composites can serve as effective, lightweight, and potentially eco-friendly shielding solutions for future space missions, including applications in the ISS.

A compact microwave metamaterial absorber is proposed for the sensing of heavy metals in tuna fish muscle. The absorber is composed of a periodic unit cell with dimensions of 6 & times; 6 mm2. The optimized design exhibits near-perfect absorption of 99.97% at 27.9 GHz within the Ka-band. The absorption rate is the same at different polarization angles. The proposed absorber is capable of detecting mercury (Hg) and lead (Pb) in tuna fish muscle by monitoring resonance frequency shifts. These shifts arise from variations in the dielectric properties of the tissue, which are measured using a single-pole Debye relaxation model. The results demonstrate clear and monotonic resonance shifts for Hg and Pb concentrations ranging from 1 to 5 & micro;g/g, while maintaining near-unity absorption. The proposed sensor achieves sensitivities up to 1.92 GHz/RIU for Hg and 1.65 GHz/RIU for Pb, along with high quality factors and figures of merit.

A quatrefoil-loop-shaped metamaterial is designed in this paper to detect explosive gases in the C and X bands. It achieves three resonance frequencies at 6.5 GHz, 7.58 GHz, and 8.7 GHz with absorption rates of 99.9 %, 93.2 %, and 96.5 %, respectively. The absorber shows the same absorption at different polarization angles from 0° to 90° in both transverse electric (TE) and transverse magnetic (TM) modes. The absorber can sense explosive gases such as propane and butane. The sensitivity of the propane and butane is 0.47 GHz/RIU and 0.5 GHz/RIU with a quality factor of 130 and 216, respectively. The Figure of Merit values are 10 for propane and 16.67 for butane. The sensing occurs based on the refractive index. The design is based on a cost-effective FR-4 (lossy) dielectric substrate. The unit cell dimensions are 8 × 8 × 1.6 mm3. Analysis of surface current, electric fields, and magnetic fields confirms strong resonance at each band. Additionally, the design's equivalent circuit is modeled and validated in Advanced Design System (ADS). The fabricated design is measured, and the measurement results agree well with the simulated response.

The authors of this study were prompted by the size and resonance behaviour constraints of the existing conventional metamaterial for satellite frequency applications to build and explore a unique metamaterial design with a split-ring resonator (SRR) structure. The proposed split-ring resonator metamaterial with intersecting metal was constructed using Computer Simulation Technique (CST) Studio Suite software. The compact SRR with the dimension 10 × 10 mm² was developed on an FR-4 substrate material and analytically simulated using the frequency domain technique by setting a frequency range from 0 to 18 GHz. The suggested SRR generated sextuple-band resonance frequencies of 3.20 (S-band), 6.05, 7.97 (C-band), 9.47 (X-band), 14.72, and 16.78 (Ku-band). The resonance frequencies exhibited both single- and double-negative features. Meanwhile, the effective medium ratio (EMR) value of the proposed SRR metamaterial is 9.38. The described SRR metamaterial is highly suited for microwave frequency applications, notably those employed in satellite communication, because of its narrow and sextuple-band responses.

Stability in multiband operation with appropriate bandwidth is a crucial factor in designing metamaterials to ensure effective performance across various electromagnetic applications. This paper introduces a quad-band unit cell design featuring triangular rings. The unit cell shows negative permeability and a refractive index at four separate frequency bands from 2 GHz to 20 GHz. A 1.5-mm-thick Rogers RT6002 dielectric material is incorporated in the design. The unit cell resonates at 2.8 GHz (S band), 5.7 GHz (C band), 9.8 GHz (X band), 12.2 GHz, and 17.3 GHz (Ku band). The corresponding transmission coefficients (S21) are −40.6 dB, −45.4 dB, −35.9 dB, −34.5 dB, and −42.4 dB, respectively. The effective operating bandwidths are 2.67–2.98 GHz, 5.14–6.19 GHz, 9.58–9.97 GHz, 11.75–12.45 GHz, and 16.05–18.45 GHz, achieving a high effective medium ratio (EMR) of 13.3. The physical and electrical dimensions of the unit cell are 8 × 8 mm2 and 0.075 λ × 0.075 λ, respectively. Numerical parameters are acquired using CST (Computer Simulation Technology) Microwave Studio 2024 software. The design is also validated with HFSS (high-frequency structure simulator) software. Additionally, the equivalent circuit is analyzed in Advanced Design System (ADS) software. The simulation results from CST, HFSS, and ADS are consistent with each other. This close agreement confirms the accuracy of the proposed design. A parametric study of various geometries, split gaps, and substrate properties highlights their effects on resonant frequencies and transmission efficiency. The proposed design demonstrates potential for use in 5G communication and quad-band satellite applications.

Synthetic materials produce microplastics, and the scarcity of natural resources as an alternative to petroleumbased materials concerns sustainable bio-materials development. Natural polymers have been utilized in different sectors due to their biocompatibility, biodegradability, and availability. The natural polymer (alginates) has been characterized as producing degradable biofilms using the casting method. The samples have been examined using GPC-MALLS, SEM-EDS, DSC-TGA, and FTIR for both treated and untreated samples of sodium alginate. The alginate (alg) films (thickness: 0.08 and 0.144 mm) were irradiated to examine their physicomechanical properties. The molecular weight (Mw) reduction (84 %) and viscosity average molecular weight (Mv) reduction (69 %) caused sensitivity to gamma-radiation. The gelling ability showed an increasing trend in adding salt (CaCl2) with Ca2+, whereas glucono-delta-lactone (GDL) performed a good hard hydrogel production. The neat alg and alg-polyvinyl alcohol-based biofilms showed remarkable changes causing the radiation on their physico-mechanical properties. Thus, the experiment's findings have shown significant interaction in the characterization and evaluation of the samples for developing sustainable biomaterials.

Radon, a naturally occurring radioactive gas, poses significant health risks, making accurate measurement crucial. This study addresses the detection and evaluation of radon gas concentrations across various environments, specifically in water, ice, air, and vacuum. Advanced techniques such as Scanning Transmission Ion Microscopy (STIM) were employed to achieve this goal. A proton beam was utilized as the primary radiation source, allowing for the identification of energy characteristics and intensities of transmitted proton beams that interact with radon gas. Considering the high costs associated with experimental setups and the complexity of measuring specific radon concentrations, Monte Carlo simulations were applied to assess how proton energy responses vary across different radon concentrations. This simulation approach not only minimizes the financial burden of physical experiments but also enhances the accuracy of radon measurements by enabling controlled variations in radon levels. Specific energy values were revealed that exhibit distinct increasing or decreasing trends correlated with varying radon concentrations. These energy signatures serve as reliable indicators for detecting the available radon in diverse environments. Overall, this study contributes to the development of more effective radon detection methods, highlighting the potential of advanced spectroscopy techniques combined with simulation-based assessments to optimize measurement accuracy under various environmental conditions. These findings lay the groundwork for developing more reliable and cost-effective radon monitoring systems, which could significantly advance environmental safety and public health initiatives.

The present study aims at examining the low-energy radiation shielding properties of a Bi2O3- and ZnO-doped borosilicate [(61-x) B2O3-10ZnO-10BaO-5TiO2-(14+x) Bi2O3; x = 4, 8, 12, and 16 mol%] glass system. The mechanical characteristics of the produced glasses were evaluated using the Makishima-Mackenzie theory. The study shows that substituting part of B2O3 with Bi2O3 reduces the microhardness and mechanical moduli of the glasses. Additionally, radiation shielding factors were determined to investigate the relationship between Bi2O3 and B2O3 content and the glasses' low-energy gamma-ray shielding performance, as well as the influence of the radiation source energy on the glass properties. The results demonstrated a positive correlation between increasing Bi2O3 concentration and the linear attenuation coefficients (LAC) of the glasses. The glass sample containing 18 mol% Bi2O3 led to the lowest LAC values, whereas the sample with 30 mol% Bi2O3 led to the highest. Furthermore, the mean free path (MFP) of the glasses was compared to that of commercial glasses to assess their effectiveness in low-energy radiation protection. The glass with the highest Bi2O3 content had the lowest MFP and thus provided better protection than some commercial alternatives.

This work presents a novel design of a three-dimensional (3D) six-port Multiple-Input-Multiple-Output (MIMO) antenna system for terahertz (THz) applications in future 6 G communication networks. The proposed design consists of 2 x 2 elements hosted on a double-sided hexagon configuration of a Polyimide substrate. Within a 6port hexagonal-shaped system, the proposed antenna achieves a 360-degree coverage area in the azimuth plane, thereby improving the utilization of the wide operational bandwidth and covering 64.70 % of the target frequency range from 0.33 THz to 0.54 THz. The MIMO system exhibits exceptional isolation exceeding 24 dB between elements, effectively mitigating unwanted signal coupling. Moreover, the antenna demonstrates a peak gain of 11.4 dBi and a high radiation efficiency of 94 %. Extensive simulations demonstrate the antenna's strong MIMO performance, showing diversity gain (DG) above 9.95 dB, an envelope correlation coefficient (ECC) below 0.001, total active reflection coefficient (TARC) under -14 dB, and channel capacity loss (CCL) <0.4 bits/s/Hz, confirming its reliability and efficiency for high-capacity wireless communication applications. These results indicate that the proposed 3D MIMO antenna system has promising applications in advanced THz wireless communication for the forthcoming era of 6 G technology.