Attenuation Coefficient Research Articles

Investigation of structural, ultrasonic, and radiation shielding properties of PbO-B2O3 glasses reinforced MnO2

Glass composition systems of (65-x) B2O3+15 PbO +15 Na2O+ 5 Al2O3+ x MnO2, where x = 0, 0.1, 0.3 and 0.5 mol% were organized by the usual melting-annealing process. Electron spin resonance (ESR) displayed broad hyperfine before and after exposing glasses to 25 kGy of gamma radiation, while sharp ESR signals at magnetic field range 3200–3500 Gauss were detected after irradiating glasses with 50 kGy. FTIR and Raman spectroscopy displayed the high structural stability of the glasses towards 25 kGy of gamma radiation, signifying the central building units of various borate groups at the same intensities and positions. Different ultrasonic characteristics such as ultrasonic velocities, elastic properties, Poisson’s ratio, Lamé constants, acoustic impedance, and ultrasonic attenuation coefficient didn’t variate greatly with gamma radiation exposure to 25 kGy. Comparing results showed that 0.5 % MnO2 glass has the most stable structure against gamma irradiation, the lowest ultrasonic velocity and wave passage, and the highest attenuation of waves, ensuring the high ability of the prepared glasses to inhibit the echoes. Experimental shielding parameters such as mass (MAC) and linear attenuation coefficients (LAC), half value layer (HVL) and tenth value layer (TVL) were measured for gamma rays and removal cross section area was measured for neutrons. Theoretical studies by WinXcom program revealed satisfactory settlement, with the experimental examinations displaying a high efficiency of the glasses to shield gamma rays especially the glass with 0.5 % MnO2, which has the highest attenuation and the lowest HVL and TVL. Therefore, the high efficiency of the glasses to be used as radiation shielding applicants in radiation institutes before 50 kGy, i.e. as storage containers for radioactive wastes in nuclear medicine.

Three-Dimensionally Printed K-Band Radar Stealth Lightweight Material with Lotus Leaf Structure.

K-band radar waves have high penetration and low attenuation coefficients. However, the wavelength of this radar wave is relatively short; thus, designing and preparing both broadband and wide-angle radar wave absorbers in this band presents considerable challenges. In this study, a resin-based K-band radar wave absorber with a biomimetic lotus leaf structure was designed and formed by UV curing. Here, microscale lotus leaf papillae and antireflection structures were prepared using a DLP 3D printer, and the contact angle between the material and water droplets was increased from 56° to 130°. In addition, the influence of the geometric parameters of the lotus leaf antireflection structure on the electromagnetic absorption performance and mechanical strength was investigated. After simulation optimization, the maximum electromagnetic loss of the lotus leaf structure 3D-printed sample was -32.3 dB, and the electromagnetic loss was below -10 dB in the 20.8-26.5 GHz frequency range. When the radar incidence angle was 60°, the maximum electromagnetic loss was still less than -10 dB. The designed lotus leaf structure has a higher mechanical energy absorption per unit volume (337.22 KJ/m3) and per unit mass (0.55 KJ/Kg) than commonly used honeycomb lightweight structures during the elastic deformation stage, and we expect that the designed structure can be used as an effective lightweight material for K-band radar stealth.

Examining three distinct rheological models with flexoelectric effect to investigate Love‐type wave velocity in bedded piezo‐structure

AbstractThe transference of the surface seismic wave at the loosely bonded common interface of a visco‐piezo composite structure is examined in the current work. With the flexoelectric effect taken into account, the structure is composed of a viscoelastic layer embedded on a piezoelectric substrate. The shear stiffness of the upper layer is thought to be described by a Kelvin–Voigt model. An analytical separable of variable method is used to derive the complex dispersion relation for both electrically open and short circuit scenarios. A numerical example is presented to demonstrate the significant influence of several influencing parameters on the wave's phase velocities and attenuation coefficients. Additionally, a graphic comparison of three rheological models – the Maxwell, Newton and Kelvin–Voigt models – is covered. Results indicate that the attenuation curve pertaining to the Maxwell and Newton model is lowest than on the Kelvin–Voigt model. Some major outcomes are highlighted here as: the prominent influence of bonding parameter is well‐proportional to the phase velocity and inversely proportional to the attenuation coefficient, and flexoelectricity has an intensive impact on both phase velocity and attenuation coefficient curves. This theoretical study leads to understanding the piezo‐flexo coupling and its potential application to design the sensors, actuators, energy harvesters and nano‐electronics.

Impact of B2O3/Co3O4 substitution on structure, physical, optical characteristics and photon attenuation capacity of borosilicate glasses

The impact of substitution of B2O3/Co3O4 in borosilicate glasses on their optical, structural, and physical characteristics as well as their ability to attenuate γ-rays was examined. Using the traditional melt quenching process, glass samples with the chemical formula (45-X)B2O3+15SiO2+ 20BaF2+20Na2O + XCo3O4, where X equals 0.0, 0.5, 1.0, 1.5, and 2.0 mol%. The prepared samples were coded as Co-0.0 - Co-2.0. XRD measurements revealed the non-crystalline character of the Co-X samples. The molar volume (Vm) decreased from 31.19 cm3/mol to 31.08 cm3/mol, although the density (ρ) increased from 2.81 g/cm3 to 2.94 g/cm3. When comparing Co-0.0 and Co-2.0, the direct optical band gap (EgDirect) values reduced from 4.32 eV to 3.77 eV, while the indirect optical band gap (EgIndirect) decreased from 3.93 eV to 3.44 eV. The Co-X glasses' Urbach's energy (EU) ranged from 0.297 eV to 0.248 eV. As the ratio of Co2+ ions rose, the optical dielectric constants of Co-X glasses, ε1 (actual part) and ε2 (imaginary portion) were improved. The linear (μ) and mass (μm) attenuation coefficients and effective atomic number (Zef) were followed the order: Co-2.0 > Co-1.5 > Co-1.0 > Co-0.5 > Co-0.0. The created Co-2.0 glass, which has the maximum amount of cobalt (III) oxide, has the lowest mean free path (MFP) and half/tenth value layers (H/TVL). The examined Co-X glasses can be employed for optical and γ-ray shielding purposes, as confirmed by the results.

Synthesis and characterization of metakaolin-based geopolymers doped with CRT waste glass for radiation shielding applications

This study presents the influence of CRT glass on the gamma-ray interaction processes in metakaolin-based geopolymers. Four batches of G-CRT composites (namely, G, G-10CRT, G-20CRT, and G-30CRT, which represent geopolymer (G) samples doped with 0, 10, 20, and 30 wt% of CRT glass) were prepared using the cold hydrostatic press method. The mass attenuation coefficients of the prepared C-xCRT samples were computed using XCOM and FLUKA simulations for photons within the energy range of 15 keV–15 MeV. The density of the pristine geopolymer increased from about 1.86 g/cm3 to 2.09, 2.26, and 2.34 g/cm3 for G-10CRT, G-20CRT, and G-30CRT, respectively. The photon mass and linear attenuation coefficients of the geopolymers increased with CRT glass concentration. The half-value layer and mean free path were within the ranges 0.070–18.079 cm and 0.101–26.083 cm for G; 0.036–15.110 cm and 0.052–21.799 cm for G-10CRT; 0.024–13.197 cm and 0.014–19.039 cm for G-20CRT; and 0.018–12.074 and 0.026–17.419 cm for G-30CRT. The G-30CRT had the best gamma attenuating prowess in contrast to other G-xCRT. CRT-rich G-xCRT had a higher effective atomic number. For 10 mm thick geopolymer, the absorbed dose rates were 0.211 μR/h, 0.66 μR/h, 1.11 μR/h, and 1.55 μR/h for G, G-10CRT, G-20CRT, and G-30CRT, respectively, for 100 keV photons. The introduction of CRT glass into the geopolymer matrix improved their photon interaction cross-section. The geopolymers showed outstanding photon interaction ability compared to ordinary concrete and some shielding glasses at low photon energies. The CRT glass-doped geopolymer samples are useful for preparing radiation shielding concrete.

Clinical value of multiparameteric quantitative ultrasound for assessing high-risk steatohepatitis

Objective: To investigate the clinical value of multiparameteric quantitative ultrasound combined with a non-invasive prediction model for assessing high-risk steatohepatitis. Methods: One hundred and ninety-four cases with metabolic-associated fatty liver disease (MAFLD) who underwent liver biopsy in Huashan Hospital, Fudan University, from June 2021 to September 2022 were selected. Shear wave elastography (SWE), shear wave dispersion (SWD) imaging, and attenuation imaging (ATI) examinations were conducted in all patients before biopsy. High-risk steatohepatitis was defined as a total activity score of ≥4 in patients with steatohepatitis, hepatocellular ballooning, and liver lobular inflammation based on pathological hepatic steatosis, inflammatory activity, and fibrosis scoring system (SAF), and fibrosis stage≥F2. Binary logistic regression analysis was used to identify the factors influencing high-risk steatohepatitis. A predictive model for diagnosing high-risk steatohepatitis was constructed using R language. The DeLong test was used to compare the area under the curve between groups. Measurement data was compared between groups using the t-test or rank-sum test, and count data were compared between groups using the χ2 test. Results: There were 46 cases (23.7%) with high-risk steatohepatitis. The quantitative ultrasound parameters included elastic modulus (OR=2.958, 95%CI: 1.889-4.883, P<0.001), dispersion coefficient (OR=1.786, 95%CI: 1.424-2.292, P<0.001) and attenuation coefficient (OR=42.642, 95%CI: 3.463-640.451, P=0.004). Serological indexes of fasting blood glucose (OR=1.196, 95%CI: 1.048-1.392, P=0.011), alanine aminotransferase (OR=1.012, 95%CI: 1.006-1.019, P<0.001), aspartate aminotransferase (OR=1.027, 95%CI: 1.014-1.042, P<0.001), γ-glutamyl transferase (OR=1.008, 95%CI: 1.001-1.017, P=0.041) and HDL cholesterol (OR=0.087, 95%CI: 0.016-0.404, P=0.003) were the factors influencing its progression. The AUCs of elastic modulus, dispersion coefficient, attenuation coefficient, multiparametric ultrasound model, serological index model, and ultrasound combined with serology model for the diagnosis of high-risk steatohepatitis were 0.764, 0.758, 0.634, 0.786, 0.773 and 0.825, respectively. The results of the DeLong test showed that the ultrasound combined with the serological model was significantly better than the serological index model and the elastic modulus, dispersion coefficient, and attenuation coefficient alone (P=0.024, 0.027, 0.038 and <0.001). Conclusion: The combination of multiparametric quantitative ultrasound is helpful for the non-invasive diagnosis of high-risk steatohepatitis and possesses great clinical significance.

Impact of nano Fe2O3 on radiation parameters of epoxy reinforced with nano carbon

This study aims to investigate the effectiveness of iron oxide (Fe2O3) and carbon black in micro and nanoscales incorporated into an epoxy adhesive matrix for gamma-ray attenuation. The composites were prepared via a simple and cost-effective synthesis method. The grain size of powder NPs was measured using a transmission electron microscope (TEM), and the particle size was about 20 ± 5 nm and 31.46 ± 2 nm for carbon and Fe2O3, respectively. The morphological properties were characterized by a scanning electron microscope, which indicated the excellent dispersion of NPs, which blocked almost all pores of the composite and increased the capability of radiation attenuation. In addition, the chemical composition of samples using energy dispersive X-rays (EDX) and the compressive strength were measured. Furthermore, the linear and mass attenuation coefficients were determined experimentally for incident photon energies of 59.51–1408.01 keV emitted from γ-ray sources using the sodium iodide scintillation detector NaI. A comparison was conducted between the experimental data and theoretical results that obtained from XCOM software, examined the validity of the experimental results. The relation deviation rate was found to vary between 0.0008 and 2.83%. Furthermore, the measurement of the relation deviation rate between the linear attenuation coefficients of micro and nano composites revealed a range of values between 1 and 25%. Also, shielding parameters such as half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), and effective atomic number (Zeff) were measured. Moreover, the equivalent atomic number (Zeq), absorption, and exposure buildup factors for prepared samples were calculated. The results showed that the incorporation of Fe2O3 NPs enhanced the shielding capability of the composites, as evidenced by the significant reduction in gamma-ray transmission. The composite materials exhibited excellent mechanical strength, making them suitable for practical applications in radiation shielding. Furthermore, it was determined that the elevation in N-Fe2O3 concentration resulted in a direct increase in the linear attenuation coefficient, from 0.314 to 0.519 cm−1 at 0.5951 MeV and from 0.099 to 0.124 cm−1 at 0.662 MeV. Nevertheless, a slight increase was discerned in the identified mass attenuation coefficients at 0.1332 and 0.1408 MeV. The experimental data for MFP, HVL, and TVL demonstrate that the EFeC4 sample exhibits optimal performance, with values of 1.9, 1.3, and 4.4 cm at 0.5951 MeV, and at 0.661 MeV, the values are 8.04, 5.57, and 18.52 cm, while at 0.1408 MeV, the values are 12.06, 8.36, and 27.78 cm, respectively. Overall, this research highlights the potential of iron oxide-carbon/epoxy composites as efficient and reliable materials for gamma-ray protection in various fields, including nuclear power plants, medical facilities, and space exploration.

Thermoluminescence response of Ce doped CaTiO3 nanophosphor synthesized by hydrothermal method for gamma dosimetry

Abstract Nanocrystalline calcium titanate (CaTiO3) doped with cerium ions (0.02 mol%) was synthesized via hydrothermal method and its luminescent properties were studied for gamma dosimetry. For the synthesized samples, the best luminescent response was achieved after annealing at 700 °C for 8 h. The synthesis was confirmed via XRD technique yielding the cyrstallite size of 22 nm for the most intense peak (121). The surface morphology was studied via scanning electron microscopy (SEM) yielding the grain size of 12 µm. The strong IR absorptions appeared at 700 cm−1 and 712 cm−1 attributed to bending mode of vibrations changing angle between Ti–O–Ti for CaTiO3 and CaTiO3:Ce respectively, as confirmed via Fourier-Transform Infrared (FTIR) Spectroscopy. Thermoluminescent (TL) response of undoped and doped samples was studied by Mikrolab RA94 TLD Reader-Analyzer having heating rate 10 °C/s, for absorbed doses 0–20 mGy from 137Cs γ-source having a dose rate 100 mSv/h. The found values at 662 keV for the photon-sensing parameters, i.e., mass attenuation coefficients (μ/ρ), mass-energy attenuation coefficient (μ en/ρ), effective atomic number for photon interaction (Z eff,PI) and effective atomic number for total photon energy absorption (Z eff,PEA) were 0.07030882 cm2/g, 0.0280245 cm2/g, 13.9 and 13.4 respectively. Thus, synthesized nanophosphor has shown excellent thermoluminescent dosimetric response for gamma radiation sensing in the selected dose range.

Radiation and mechanical performance of cementitious materials containing ecofriendly nano laboratory waste glass

This study helps in managing waste glass and greening the environment by incorporating laboratory waste glass into mortar production to make an eco-friendly shielding material against gamma rays. The efficiency of using waste glass powder as a cement replacement or addition in mortar production was studied by using two waste glass sizes: micro glass (particle size range from 10.09 to 24.73 μm) and nano glass (particle size range from 10.57 to 26.42 nm) to design different mortar specimens with varying percentages of fine glass powder from 0 to 30%. Compressive strength and flexure strength were evaluated to determine mechanical properties. The results indicated that adding WGP to mortar positively affects the characteristics of cementitious composites. The linear and mass attenuation coefficients of the samples were experimentally determined using a NaI detector and various radioactive sources (Am-241, Ba-133, Eu-152, Cs-137, and Co-60) with gamma energies ranging from 59.53 to 1332 keV. The obtained coefficients were then compared to the theoretical values of the composites using XCOM software to verify their accuracy. Additionally, the half-value layer, tenth-value layer, mean free path, and effective atomic number were computed. Furthermore, the results revealed that the mortar sample with 30% nano additive glass was the most effective in reducing gamma radiation.

Experimental investigation of fired clay bricks for gamma radiation shielding

In this study, the focus was on evaluating how the physical and structural attributes of red clay bricks influence their ability to shield γ-rays. The red clay brick samples' density (ρ, g/cm3) was measured using the MH-300A density meter. The minerals present in the selected clay were identified through the application of X-ray diffraction. Moreover, the material's morphology and chemical composition were studied using scanning electron microscopy. By increasing the pressure rate (PR) from 7.61 to 114.22 MPa, the density of the synthetic clay bricks was increased from 1.50 to 1.69 g/cm3. Subsequently, the gamma-ray shielding effectiveness of the clay bricks produced was investigated through experiments utilizing a NaI (Tl) detector with exposure to various gamma sources. The experimental data illustrated a rise in the linear attenuation coefficient (μ) of the proposed clay bricks, progressing from 1.352 ± 0.040 to 1.559 ± 0.068 cm−1, from 0.111 ± 0.003 to 0.123 ± 0.005 cm−1 and from 0.087 ± 0.002 to 0.099 ± 0.003 cm−1 at γ-ray energies of 0.033, 0.662, and 1.332 MeV, respectively. The rise in μ resulted in a reduction in the half-value thickness (Δ0.5), lead equivalent thickness (Δeq) and transmission factor (TF), in the synthetic bricks. Additionally, samples with increased thickness exhibited enhanced effectiveness in shielding gamma radiation, making them suitable for various applications requiring radiation protection. Moreover, the detection of pressure rate's influence on the physical and shielding characteristics of clay bricks was observed at specific gamma energies. (0.033, 0.662 and 1.332 MeV).

Ion Leakage Current Control for Polycrystalline Metal Halide Perovskite Direct X-ray Detectors.

Metal halide perovskites have emerged as promising materials for X-ray detection due to their high X-ray attenuation coefficients, defect tolerance, and suitability for large-area, low-temperature fabrication. However, the intrinsic high ion conductivity of these materials presents challenges, such as high dark current density and current drift, which impair the stability and sensitivity of perovskite X-ray detectors. This study introduces an approach to mitigating these issues by incorporating 2,2,3,3,3-pentafluoropropylamine hydrochloride (PFH) into polycrystalline MAPbI3-xClx films using a one-step blade-coating method. PFH aggregates at grain boundaries, raising local vacuum energy levels and passivating surface defects, thereby reducing ion conductivity without affecting electron conductivity. As a result, this approach significantly reduces the dark current and enhances sensitivity, achieving a low detection limit of 14.7 nGyair/s. Additionally, it improves signal stability, consistency, and response speed of the detector. These findings suggest that PFH is a promising additive for advancing the performance and practical application of polycrystalline metal halide perovskite-based X-ray detectors.

The impact of pressure rate on the physical, structural and gamma-ray shielding capabilities of novel light-weight clay bricks

The present study focuses on investigating the gamma-ray protection features of clay bricks for potential use in radiation shielding fields. The study examined the physical and structural features that affect the performance of these stones in shielding γ-rays. The density (ρ, g/cm3) of the clay bricks samples was measured utilizing the MH-300A density meter. Additionally, the mineral structure within the annealed pressed clay samples was identification the XRD spectrometry. Moreover, the morphology and elemental chemical composition for the annealed bricks were examined using a Thermo Scientific Prisma E, USA field emission Scanning Electron Microscope (SEM) in conjunction with Energy Dispersive X-ray Spectroscopy. Besides, the shielding features of the clay bricks were analyzed using the experimentally measurements (by NaI (Tl) scintillation detector), XCOM software, and Monte Carlo Simulation over the γ-ray energy interval of 0.033–1.332 MeV. The findings of the study indicate that an increase in the pressure rate within the clay bricks samples leads to the rise in their density (from 1.62 to 1.87 g/cm3). This increase in density is accompanied by a decline in both porosity (Φ, %) (from 34.75 to 26.21 %) and water absorption (K, %) (from 26.21 to 14.74 %) factors. Furthermore, the increase in pressure rate from 7.61 to 114.22 MPa also results in an increase in the linear attenuation coefficient (μ, cm−1) of the clay bricks under study. This is achieved by increasing the μ values from 0.39 to 0.43 cm−1, from 0.13 to 0.15 cm−1, and from 0.09 to 0.10 cm−1, at 0.081, 0.511 and 1.173 MeV, respectively. The synthetic bricks offer a lead-free and efficient option for protection, making them ideal for use in nuclear facility start-ups or in areas with radiation exposure.

In Silico clinical trial to predict the efficacy of hip protectors for preventing hip fractures

Osteoporosis is characterized by loss of bone mineral density and increased fracture risk. Reduction of hip fracture incidence is of major clinical importance. Hip protectors aim to attenuate the impact force transmitted to the femur upon falling, however different conclusions on their efficacy have been reported; some authors suggest this may be due to differences in compliance. The aim of this study was to apply an In Silico trial methodology to predict the effectiveness of hip protectors and its dependence on compliance.A cohort of 1044 virtual patients (Finite Element models of proximal femur) were generated. A Markov chain process was implemented to predict fracture incidence with and without hip protectors, by simulating different levels of compliance. At each simulated follow-up year, a Poisson distribution was randomly sampled to determine the number of falls sustained by each patient. Impact direction and force were stochastically sampled from a range of possible scenarios. The effect of wearing a hip protector was simulated by applying attenuation coefficients to the impact force (12.9 %, 19 % and 33.8 %, as reported for available devices). A patient was considered fractured when impact force exceeded the femur strength.Without hip protector, virtual patients experienced 66 ± 5 fractures in 10 years. Wearing the three devices, fracture incidence was reduced to 43 ± 4, 35 ± 4 and 17 ± 2 respectively, at full compliance. As expected, effectiveness was dependent on compliance.This In Silico trial technology can be applied in the future to test multiple interventions, optimise intervention strategies, improve clinical trial design and drug development.

Characterization of ferrous-xylenol orange-polyvinyl alcohol gel for gamma dosimetry using spectroscopy

Abstract Fricke gel dosimeters are appropriate candidates for gamma dosimetry. Polyvinyl alcohol Fricke gel dosimeters are the most recent introduced gel dosimeters which have low ion diffusion. In this work, samples of ferrous-xylenol orange-polyvinyl alcohol gel dosimeters were prepared and characterized using optical spectroscopy. Using win XCOM program and the elemental composition of the gel, the mass attenuation coefficients for photons were evaluated. The results exhibited that the prepared gel is the nearly radiological blood-, soft tissue- and water-equivalent. The 60Co gamma cell unit was used to irradiate the gel samples. A dose range response was found linear from 10 to 30 Gy and suitable for blood irradiation dosimetry. Additionally, the gel response good repeatability was confirmed by the coefficient of variation calculations. Furthermore, chemical yield of the gel was estimated to be 34.6. The good characteristics of the prepared gel make it appropriate for dosimetry of blood irradiators.

Indirect effect of elevated pressure via the modulations of crystals intrinsic parameters on radiation shielding efficacy: A comparative study between two α-quartz homeotypes SiO2and GeO2

This study investigates the indirect effects of elevated pressure on the radiation shielding competence of two α-quartz homeotypes, SiO2 and GeO2, by examining the modulations of their crystal intrinsic tetrahedral parameters. The study focuses on structural modifications and their correlations with radiation attenuation properties. The results show that both homeotypes exhibit energy-dependent mass attenuation coefficients (MAC) and linear attenuation coefficients (LAC). SiO2 demonstrates higher transparency to incident radiation compared to GeO2, with a relative difference in MAC values of 91% at 0.015 MeV, decreasing to 28% at 15 MeV. However, within the energy range of 0.4 < E < 4 MeV, SiO2 exhibits higher MAC values than GeO2, with the MAC of SiO2 surpassing GeO2 by 17% at 0.4 MeV. The pressure dependence of LAC values indicates that both SiO2 and GeO2 become more effective in attenuating radiation under higher pressure conditions. For instance, at 0.015 MeV, the LAC of GeO2 increased from 274.826 cm−1 at 0.001 GPa to 308.073 cm−1 at 5.57 GPa. GeO2 generally exhibits higher LAC values than SiO2 across the energy and pressure ranges studied. It can be concluded that the structural modifications induced by elevated pressure significantly enhance the radiation shielding capabilities of α-quartz homeotypes, particularly GeO2, making them promising candidates for advanced shielding materials in various high-radiation environments.

Influence of the clay fractions from various horizons on the radiation shielding parameters of an Arenosol

Abstract This study examines the effects of the chemical composition of the clay fraction of various soil horizons on radiation shielding parameters. X-ray fluorescence (XRF) analysis did not reveal significant differences in the concentration of the most abundant oxides (Al2O3, SiO2, Fe2O3) among the various horizons. Consequently, the mass attenuation coefficient did not vary among the horizons in terms of the photon energies studied (15 keV–10 MeV). The mean free path (MFP), half-value layer (HVL) and tenth-value layer (TVL) did not differ for energies up to 100 keV. However, at higher energies, these parameters were mainly influenced by the differences in the densities of the soil horizons. The effective atomic number did not differ across the horizons for the various photon energies, nor did the mass attenuation coefficient. It is shown that slight differences in the chemical composition of the clay fraction of soil horizons do not affect radiation shielding parameters (MFL, HVL, TVL) for low photon energies (&lt;500 keV). Density is more important for radiation shielding than the chemical composition of the various horizons of the same soil type for higher energies (&gt;100 keV); hence, compacting the clay fraction might be more efficient for radiation shielding purposes at higher energies.

Promoting Gas Extraction Technology with Screen Pipe for Long Borehole Protection in Soft Seam

The inherent properties of soft coal seams and their mechanical environment make long boreholes susceptible to issues like collapse, deformation, and blockages. These problems shorten the service life of the boreholes and hinder extraction efficiency. This paper tackles these challenges by analyzing the deformation and damage patterns of long boreholes in soft coal seams. It examines the stress distribution and deformation characteristics around both protected and unprotected boreholes at different burial depths. Additionally, it recommends using screen pipe protection technology to improve gas extraction and mining operations, as demonstrated in Changping Coal Mine. The results show that screen pipe protection substantially improves the stress distribution and deformation stability of coal seam boreholes. The flow attenuation coefficients of two boreholes equipped with protection technology decreased by 48% and 61%. After 50 days of extraction from boreholes with a protection rate exceeding 90%, gas concentration remained above 50%, which is 2.59 times higher than that of unprotected boreholes. This technology effectively addresses the frequent accidents, poor extraction performance, and inefficiency of long boreholes in soft coal seams, ensuring the mine’s safe and efficient production.

Measurement of the nonlinear refractive index of highly scattering aerosols

The quality of air significantly impacts both the quality of life and the health of individuals. Femtosecond laser filament-induced nonlinear spectroscopy effectively measures both aerosol concentration and composition. Specifically, the nonlinear refractive index coefficient of the atmosphere directly influences the nonlinear propagation of femtosecond lasers in the air. The presence of aerosol particles in the atmosphere, particularly water droplets, may affect this nonlinear refractive index coefficient. However, the measurement of the nonlinear refractive index coefficient of highly scattering aerosols has not yet been reported. In this paper, a method to obtain the nonlinear refractive index coefficients of aerosols based on spectral changes is presented. Experiment measured the n2 coefficient of the air and water vapor aerosols respectively. Experimental results show that the n2 coefficients are 2.5 × 10−19 cm2/W and 2.4 × 10−19 cm2/W respectively for air with incident energy of 48 μJ and 68 μJ, the n2 coefficient are 2.5 × 10−19 cm2/W and 2.3 × 10−19 cm2/W respectively for aerosol with attenuation coefficients of 0.029 dB/cm. When the concentration of aerosols was increased to an attenuation coefficient of 0.045 dB/cm, the nonlinear refractive index coefficient of the aerosols was 3.1 × 10−19 cm2/W. The experimental results indicated that low concentrations of aerosols did not affect the nonlinear refractive index coefficient of air, but as the concentration increased to a certain level, the nonlinear refractive index coefficient of air increased. This work provides a simpler and faster technical route for measuring the n2 coefficient of gaseous media, offers a new approach to the problem of measuring the nonlinear refractive index of thick, highly scattering media, and addresses the shortcomings of the z-scan.

Determination of radiation shielding performance of phospo-silicate glass by introducing tellurite oxide modifier

Current research investigated the performance of phosphor-silicate glasses as gamma-ray shields. The mass attenuation coefficients (μ/ρ) of the chosen glasses were determined using the both Phy-x/PSD and WinXcom codes. From the results obtained, both approaches yield (μ/ρ) values that are found to be in good agreement with each other. These values are then used to compute the half-value layer, effective atomic number, mean free path, and energy exposure buildup factors. Taken from the results, the EBFs for the current glasses were observed to be small in the low energy region (in order of unity at E ¼ 0.015 MeV) and then reach maximum value for all glasses at 40 mfp in the high-photon energy region. The obtained results have been contrasted with that of window glasses and a few common shielding concretes. It was found that the chosen glasses are highly effective in gamma shielding applications, as indicated by the lower mean free path values.

Prediction Models for the Hybrid Effect of Nano Materials on Radiation Shielding Properties of Concrete Exposed to Elevated Temperatures

In modern construction, nanomaterials can be added to concrete to improve its radiation shielding properties. A prediction model for the gamma-ray radiation shielding properties, such as linear attenuation coefficient (LAC) of nanomaterial-based concrete remains necessary. This study aims to develop prediction models for LAC of nano modified concrete (NMC) using nano alumina (NA) and carbon nano tubes (CNTs) subjected to high temperatures. These models are based on linear regression and three machine learning algorithms: M5 Prime (M5P), random forest (RF), and extreme gradient boosting (XGBoost). To build the models, results of 117 concrete cubic specimens (100mm size) was utilized as a dataset with varying amounts of NA and CNTs. Relevant variables including temperature, exposure time, and NA and CNTs dosages were considered. To further validate the predicted results, various statistical metrics and K-fold cross-validation were employed to compare and validate the models' output. The results showed that the XGBoost model outperformed other models, with the highest R2 of 0.9975 and the lowest error of 0.4365%. In addition, the impact of each parameter on LAC of NMC was assessed using Shapley Additive Explanations (SHAP) analysis. Sensitivity and SHAP analyses reveal that CNTs has the highest influence on the radiation shielding properties of NMC. In comparison with the previously developed ANN model, the XGBoost and ANN models showed approximately the same prediction power for predicting LAC of NMC.