• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1634-1641
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• 2021

Exposure to gamma-rays is hazardous for humans and other living beings because of their high penetration through the materials. For this reason, shielding materials (usually lead, copper and stainless steel) are used to protect against gamma rays. This study's objective was to prepare ceramic materials for gamma radiation shielding by using different natural bentonite clays. Gamma-ray attenuation performances of the prepared shielding materials at different thicknesses were investigated and evaluated for different gamma-ray energies from different standard point gamma radiation sources (²⁵¹Am, ⁵⁷Co, ¹³⁷Cs, ⁶⁰Co, and ⁸⁸Y). The mass and linear attenuation coefficients of the prepared ceramics vary between 0.238 and 0.443 cm² g^-1 and between 0.479 and 1.06 cm^-1, respectively, depending on their thicknesses. Results showed that these materials could be prioritized because of their evidential properties of gamma radiation protection in radiation applications.

• Nuclear Engineering and Technology
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• v.54 no.9
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• pp.3459-3469
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• 2022

Matrix composites of n-WO₃/n-Bi₂O₃/PVA with different loadings of n-WO₃/n-Bi₂O₃ mixtures (0-15 wt%) and starch (0 and 3 wt%) were fabricated by using melt-mixing method. The X-ray attenuation capability were evaluated based on mass attenuation coefficient (μ/⍴) using a general diagnostic X-ray machine at 40-100 kVp. The effect of starch addition on the dispersion of the fillers in the PVA matrix were observed by using FESEM through morphological analysis. The fabricated samples have shrunken and caused their thickness to be decreased (0.35 mm-0.55 mm) after the drying process even though fixed thickness (2.0 mm) was set initially. The density and HVL values of the samples with 3 wt% starch was seen lower than samples without starch (0 wt%), however the former have provided improvement in filler dispersion and better X-ray attenuation capability compared to the latter. As conclusion, the matrix composite of n-WO₃/n-Bi₂O₃/PVA with 15 wt% of n-Bi₂O₃, 8 wt% of n-WO₃ and 3 wt% starch can be selected as the best promising candidate for X-ray shielding materials.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2613-2620
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• 2023

Excellent thermal neutron absorption performance of boron expands the potential use of boron rich slag to prepare epoxy resin matrix nuclear shielding composites. However, shielding attenuation behaviors and mechanism of the composites against gamma rays are unclear. Based on the radiation protection theory, Phy-X/PSD, XCOM, and ⁶⁰Co gamma ray source were integrated to obtain the shielding parameters of boron rich slag/epoxy resin composites at 0.015-15 MeV, which include mass attenuation coefficient (µ_t), linear attenuation coefficient (µ), half value thickness layer (HVL), electron density (N_eff), effective atomic number (Z_eff), exposure buildup factor (EBF) and exposure absorption buildup factor (EABF).µ_t, µ, HVL, N_eff, Z_eff, EBF and EABF are 0.02-7 cm²/g, 0.04-17 cm^-1, 0.045-20 cm, 5-14, 3 × 10²³-8 × 10²³ electron/g, 0-2000, and 0-3500. Shielding performance is BS4, BS3, BS3, BS1 in descending order, but worse than ordinary concrete. µ and HVL of BS1-BS4 for ⁶⁰Co gamma ray is 0.095-0.110 cm^-1 and 6.3-7.2 cm. Shielding mechanism is main interactions for attenuation gamma ray by BS1-BS4 are elements with higher content or higher atomic number via Photoelectric Absorption at low energy range, and elements with higher content via Compton Scattering and Pair Production in Nuclear Field at middle and higher energy range.

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3872-3883
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• 2024

This study investigates the effects of Zinc (Zn), Manganese (Mn), and Iron (Fe) additions on the microstructure, corrosion behaviour, biocompatibility, mechanical, and gamma-ray shielding properties of Magnesium (Mg) alloys prepared in various compositions using powder metallurgy (PM). The microstructure and mechanical properties of these alloys were analyzed using electron microscopes (SEM and FE-SEM) and X-ray diffraction (XRD) methods. The results showed positive changes in the material's structure when the percentage of zinc added to pure magnesium increased. It was observed that the material became ductile, and the ductile fracture increased when the zinc ratio increased. The gamma-ray shielding properties of newly produced Mg-based alloys have also been discussed since they have a high potential for use in space technologies. Radiation shielding measurements have been performed using a 3" × 3" NaI(Tl) scintillation detector NaI (Tl) gamma-ray spectrometer. The gamma-ray shielding parameters such as the linear attenuation coefficients (μ_l), mass attenuation coefficient (μ_m), effective atomic number (Z_eff), half-value layer (HVL), and tenth-value layer (TVL) have been determined experimentally at photon energies of 0.511 MeV (emitted from a²²Na radioactive point source) and 1.173 MeV and 1.332 MeV (emitting from a⁶⁰Co radioactive point source). The obtained parameters have been compared to the theoretical results of the XCOM software, and a satisfactory agreement has been found. It can be said from the results that the Mg30Zn alloy has the best shielding properties among the produced materials.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.301-308
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• 2024

Ceramic materials are being explored as alternatives to toxic lead sheets for radiation shielding due to their favorable properties like durability, thermal stability, and aesthetic appeal. However, crafting effective ceramics for radiation shielding entails complex processes, raising production costs. To investigate local viability, this study evaluated Malaysian ceramic tiles for shielding in diagnostic X-ray rooms. Different ceramics in terms of density and thickness were selected from local manufacturers. Energy Dispersive X-ray Fluorescence (EDXRF) and X-ray Fluorescence (XRF) characterized ceramic compositions, while Monte Carlo Particle and Heavy Ion Transport code System (MC PHITS) simulations determined Linear Attenuation Coefficient (LAC), Half-value Layer (HVL), Mass Attenuation Coefficient (MAC), and Mean Free Path (MFP) within the 40-150 kV energy range. Comparative analysis between MC PHITS simulations and real setups was conducted. The C3-S9 ceramic sample, known for homogeneous full-color structure, showcased superior shielding attributes, attributed to its high density and iron content. Notably, energy levels considerably impacted radiation penetration. Overall, C3-S9 demonstrated strong shielding performance, underlining Malaysia's potential ceramic tile resources for X-ray room radiation shielding.

• Korean Journal of Applied Biomechanics
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• v.26 no.2
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• pp.167-174
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• 2016

Objective: The purpose of this study was to determine the interrelationship between ranges of motion of the knee and ankle joints on the sagittal plane and the attenuation magnitude of impact shock at high frequency (9~20 Hz) in the support phase during downhill running. Method: Fifteen male heel-toe runners with no history of lower extremity injuries were recruited for this study (age, $25.07{\pm}5.35years$; height, $175.4{\pm}4.6cm$; mass, $75.8{\pm}.70kg$). Two uniaxial accelerometers were mounted to the tuberosity of tibia and sacrum, respectively, to measure acceleration signals. The participants were asked to run at their preferred running speed on a treadmill set at $0^{\circ}$, $7^{\circ}$, and $15^{\circ}$ downhill. Six optical cameras were placed around the treadmill to capture the coordinates of the joints of the lower extremities. The power spectrum densities of the two acceleration signals were analyzed and used in the transfer function describing the gain and attenuation of impact shock between the tibia and the sacrum. Angles of the knee and ankle joints on the sagittal plane and their angle ranges were calculated. The Pearson correlation coefficient was used to test the relationship between two variables, the magnitude of impact shock, and the range of joint angle under three downhill conditions. The alpha level was set at .05. Results: Close correlations were observed between the knee joint range of motion and the attenuation magnitude of impact shock regardless of running slopes (p<.05), and positive correlations were found between the ranges of motion of the knee and ankle joints and the attenuation magnitude of impact shock in $15^{\circ}$ downhill running (p<.05). Conclusion: In conclusion, increased knee flexion might be required to attenuate impact shock during downhill and level running through change in stride or cadence while maintaining stability, and strong and flexible ankle joints are also needed in steeper downhill running.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.3
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• pp.275-284
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• 2006

In the measurement of gamma rays emitted from the nuclide in the radioactive waste drum, to analyze the nuclide concentration accurately, it is necessary to use the proper calibration standards and to correct for the attenuation of the gamma rays. Two drums having a different density were used to analyze the nuclide concentration inside the drum in this study. After carrying out the system calibration, we measured the gamma rays emitted from the standard source inside the model drum with changing the distance between the drum and the detector. The measured values were corrected with the three kinds of gamma attenuation correction methode, as a results, the error was less than 10 % in the low density drum and less than 25 % in the high density drum. The measured activity in the short distance was more accruable than in the long distance. The transmission correction for the mass attenuation showed good results(very Low error) compared to the mean density and the differential peak correction method.

• Radiation Oncology Journal
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• v.15 no.2
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• pp.153-158
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• 1997

Purpose : The Dual-Energy Quantitative Computed Tomography(DEQCT) was compared with bone equivalent $K_2HPO_4$ standard solution and ash weight of animal cadaveric trabecular bone in the measurement of bone mineral contents(BMC). Method and Materials : The attenuation coefficient of tissues highly depends on the radiation energy density and effective atomic number of composition, The bone mineral content of DEQCT in this experiments was determined from empirical constants and mass attenuation coefficients of bone,fat and soft tissue equivalent solution in two photon spectra. In this experiments, the BMC of DEQCT with 80 and $120kV_p$ X rays was compared to ash weight of animal trabecular bone. Results : We obtained the mass attenuation coefficient of 0.2409 0.5608 and 0.2206 in $80kV_p$, and 0.2046, 0.3273 and $0.1971cm^2/g$ in $120kV_p$ X-ray spectra for water bone and fat equivalent materials, respectively. The BMC with DEQCT was acomplished with empirical constants $K_1=0.3232,\;K_2$=0.2450 and mass attenuation coefficients has very closed to ash weight of animal trabecular bone The BMC of empirical DEQCT and that of manufacturing DEQCT were correlated with ash weight as a correlation r= 0.998 and r= 0.996, respectively. Conclusion : The BMC of empirical DEQCT using the experimental mass attenuation coefficients and that of manufacture have showed very close to ash weight of animal trabecular bone.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1323-1330
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• 2021

This work reported the radiation shielding characteristic of the bismuth titanium vanadium sodium tellurite glass system. The density of the specially-developed glass samples was increased from 2.21 to 4.01 g/cm³ with the addition of Bi₂O₃, despite the fact the molar volume is decease within 85.43-54.79 cm³/mol. The WinXcom program was used to approximate the effect of Bi₂O₃ on the gamma radiation shielding parameters of bismuth titanium vanadium sodium tellurite glasses. The ㎛ values decrease with the increase of Bi₂O₃ concentration. The computed data shows that the glass sample with 20 mol.% of Bi₂O₃ content has the greatest radiation attenuation performance in comparison to other selected glasses. The Bi₂O₃-TiO₂-V₂O₅-Na₂O-TeO₂ glass system shows excellent neutron shielding material with high long-term light transmittance and discharge resistance and could be potentially used as transparent radiation-resistant shielding glass applications.

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3796-3803
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• 2024

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 (E_g) 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 (T_g) 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 (${\overline{HVL}}$) 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.