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The efficiency of geopolymers as an effective immobilization system for various hazardous waste materials can be enhanced by adding PbO to improve its radiation shielding characteristics. In this study, the impact of PbO addition on the shielding properties of geopolymer composites was examined to evaluate the gamma radiation shielding characteristics of the geopolymer using FLUKA and XCOM computer programs. The results showed that adding 10% and 20% lead oxide significantly improved the shielding properties of the investigated geopolymer, mostly at lower photon energies. The higher values of MAC of 59.66728 cm2/g at 0.015 MeV, and 0.03916 cm2/g at 15 MeV for the investigated geopolymers suggest that these materials have improved radiation shielding at lower and intermediate energies due to higher photoelectric absorption and Compton scattering. The findings of this study provided valuable insights for designing high-performance radiation protection in medical imaging facilities, nuclear power plants, industrial radiography and other special radiation installations. Therefore, GEO doped with 20PbO should be deployed to fortify these facilities against ionizing radiations. [ABSTRACT FROM AUTHOR]

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 (Al 2 O 3 , SiO 2 , Fe 2 O 3) 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 (<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 (>100 keV); hence, compacting the clay fraction might be more efficient for radiation shielding purposes at higher energies. [ABSTRACT FROM AUTHOR]

This research aims to determine and quantify the radiation shielding characteristics of high-density polyethylene/ tungsten oxide (HDPE/WO3) nanocomposites including the linear attenuation coefficient (μ), mass attenuation coefficient (μ/ρ), half-value layer (HVL) and tenth-value layer (TVL) for photons at various energies using Geant4, XCOM, and experiment. Thus, HDPE was chosen as the polymer matrix. Then, the samples at various concentrations of WO3 nanoparticles (0, 1, 2, 3, 4, 5, 6, and 9.5 wt.%), different graphene oxide (GO) weight percentages (0, 0.25, 0.5, and 1 wt.%), and 10 and 20 wt.% linear low-density polyethylene (LLDPE) were fabricated. An NaI (Tl) scintillation detector was used to measure the shielding quantities using the 201Tl, and 99mTc sources at three energies of 135, 140, and 167 keV. The experimental results demonstrated that the addition of GO and LLDPE to the HDPE matrix resulted in a more uniform sample. Incorporating 20% LLDPE into the HDPE polymer matrix for the 99mTc resulted in an 18% rise in μ compared to pure HDPE. Finally, the experimental results revealed a comparatively good agreement with the Geant4 and XCOM simulations.

This research aims to determine and quantify the radiation shielding characteristics of high-density polyethylene/ tungsten oxide (HDPE/WO3) nanocomposites including the linear attenuation coefficient (µ), mass attenuation coefficient (µ/ρ), half-value layer (HVL) and tenth-value layer (TVL) for photons at various energies using Geant4, XCOM, and experiment. Thus, HDPE was chosen as the polymer matrix. Then, the samples at various concentrations of WO3 nanoparticles (0, 1, 2, 3, 4, 5, 6, and 9.5 wt.%), different graphene oxide (GO) weight percentages (0, 0.25, 0.5, and 1 wt.%), and 10 and 20 wt.% linear low-density polyethylene (LLDPE) were fabricated. An NaI (Tl) scintillation detector was used to measure the shielding quantities using the 201Tl, and 99mTc sources at three energies of 135, 140, and 167 keV. The experimental results demonstrated that the addition of GO and LLDPE to the HDPE matrix resulted in a more uniform sample. Incorporating 20% LLDPE into the HDPE polymer matrix for the 99mTc resulted in an 18% rise in µ compared to pure HDPE. Finally, the experimental results revealed a comparatively good agreement with the Geant4 and XCOM simulations. [ABSTRACT FROM AUTHOR]

The study of lead-free glasses for radiation shielding applications has drawn global attention. This work aimed to theoretically investigate the impact of Bi2O3 on X-ray shielding characteristics of telluro-borate-bismuth glass samples, in the 15−300 keV energy region. Sample S5 (55Bi2O3 - 5TeO2 - 20SrO - 5ZnO - 15Bi2O3 ) yielded highest LAC, MAC, and Ze f f (1.066−252.061 cm−1, 0.249−58.893 cm² /g, and 67.81−30.16), alongside the lowest HV L, TV L, and MFP (0.003− 0.650 cm, 0.009−2.160 cm, and 0.004−0.938 cm). Hence, S5 emerged as the most effective X-ray shielding glass among the samples studied. [ABSTRACT FROM AUTHOR]

The glass series modified by tungsten oxide was created using the compounds (75-x) B2O3– 10SrCO3– 8TeO2– 7ZnO - xWO3, where x = 0, 1, 5, 10, 22, 27, 34, and 40% mole percentage. A UV–visible spectrophotometer and thermogravimetric-differential thermal analysis (TG-DTA) methods were employed to characterize the specimen's optical and phase transition attributes, respectively. The mass-attenuation coefficient (AC) of all created glasses from BSTZW0 to BSTZ7 was estimated using Geant4 code from 0.05 to 3 MeV and compared to the XCOM software results, with a relative difference of less than 2% between the two results. The increase of WO3 percentage lead to an increase in the Linear-AC at each studied energy, and this is mainly due to the fact that the higher the percentage of WO3 in the glass increases its density which causes an increase in the Linear-AC, so an energy of 0.06 MeV, as an example, the values of the Linear-AC was 4.009, 4.509, 5.442, 6812, 8.564, 9.856, 10.999 and 11.628 cm−1 form BSTZW0 too BSTZW7, respectively. The Half-VL (value layer), Mean-FP (free path), Tenth-VL, and Radiation attenuation performance (RAP) were also calculated for the current BSTZW-glass samples and revealed that BSTZW7 had the best gamma ray attenuation performance at all discussed energies when compared to other studied glass samples.

We determined the radiation shielding properties for 10CaO–xPbO–(90-x) deteriorated silica gel (DSG) glass system (x = 20, 25, 30, 35, 40, and 45 mol.%). The mass attenuation coefficient (MAC) has been estimated at photon energies of 74.23, 97.12, 122, 662, 1173, and 1332 keV using a narrow beam X-ray attenuation and transmission experiment, the XCOM program, and a PHITS simulation. The obtained MAC values were applied to estimate the half value layer (HVL), mean free path (MFP), effective atomic number, and effective electron density. Results show that the MAC value of the studied glasses ranges between 0.0549 and 1.4415 cm2/g, increases with the amount of PbO, and decreases with increasing photon energy. The HVL and MFP values decrease with increasing PbO content and increase with increasing photon energy. The recycled glass, with the addition of PbO content (20–45 mol.%), exhibited excellent radiation shielding capabilities compared to standard barite and ferrite concretes and some glass systems. Moreover, the experimental radiation shielding parameters agree with the XCOM and PHITS values. This study suggests that this new waste-recycled glass is an effective and cost-saving candidate for X-ray and gamma-ray shielding applications.

In this work, the effect of Multi-Wall Carbon Nanotubes (MWCNTs) addition on the materials shielding properties against Gamma radiation with an energy of 662 keV from a 137Cs source is investigated. The linear attenuation coefficient of MWCNTs-based materials (gelatin-water mixture) with MWCNTs concentrations of 0%, 5%, and 10% is measured. To isolate the contribution of the MWCNTs unique structure to the shielding capabilities, samples with the same concentrations of activated carbon were fabricated and their linear attenuation coefficients were obtained. Also, the linear and the mass attenuation coefficients are obtained theoretically for the same concentrations using the XCOM program and compared with measured values. It is found that the addition of MWCNTs by 5% or 10% has increased the linear attenuation coefficient by around 5% when compared to the same concentrations of activated carbon. This increase in the shielding apabilities against gamma radiation can be related to the interaction of gamma radiation with the extraordinary geometry and structure of MWCNTs.

In various medical, industrial, and nuclear facilities, it is very necessary to have enough shielding against the radiation released by regularly employed isotopes. In this work, we concentrate on nuclear security as well as the radiation shielding against gamma attenuation capabilities of the borate glasses, including Te and Cu. These glasses have the chemical form of (100-x)[30B2O3–70TeO2]-xCuO, where x = 0, 0.005, 0.01, 0.015, 0.02 wt%. The systems were represented by five distinct samples, labelled as BTCu-20, BTCu-15, BTCu-10, BTCu-5, and BTCu-0, where the number refers to the percentage of CuO in the mixture and the remainder is made up of TeO2 and B2O3. Through the use of FLUKA simulations, the basic characteristics associated with gamma shieldings, such as attenuation and transmission factors, were examined for the particular energy range of 238–1408 MeV emitted from 133Ba, 137Cs, 60Co, 152Eu, and 232Th. The effect of the systematic replacement of CuO by B2O3 and TeO2 on the shielding qualities was explored in depth for gamma radiation. In addition, comparison research was carried out between the currently available borate glasses and the traditional shielding materials. According to the findings of the current investigation, the GHVL was found to be its lowest at 238 keV with values of 0.87, 0.92, 0.98, 1.04, and 1.10 (cm) for BTCu-0, BTCu-5, BTCu-10, BTCu-15, and BTCu-20 glasses, respectively. This points to the possibility that the BTCu-0 sample might be used in radiation shielding applications, which would result in increased nuclear safety.

Conteúdos relacionados à área de Física Moderna envolvem o conhecimento da produção e interação da radiação com a matéria. A manifestação macroscópica dessa interação se evidencia pela atenuação da radiação incidente no material. Neste estudo, apresenta-se o uso de um aparato experimental destinado a práticas de ensino visando a determinação do coeficiente de atenuação do chumbo para fótons de raios gama provenientes de uma fonte de 137Cs (fótons com energia de aproximadamente 662 keV). Tradicionalmente, essa determinação é realizada utilizando-se como material absorvedor placas de chumbo de espessuras conhecidas. Entretanto, em geral, esse enfoque leva a resultados discrepantes em relação ao valor do coeficiente de atenuação teórico para o chumbo, com desvios em torno de 15%. No método aqui apresentado, sugere-se a substituição das placas por esferas ou pó de chumbo. Os resultados obtidos mostram que o método proposto reduziu sensivelmente os desvios do coeficiente de atenuação medido em relação aos valores teóricos (simulados). Na melhor condição experimental os erros ficaram entre 2 e 4%. Entre as grandes vantagens do método abordado estão à possibilidade de variações contínuas na espessura e na geometria do material absorvedor e análise da influência de sistemas porosos na medida da atenuação da radiação.

Various photon attenuation software tools are being used widely by researchers to evaluate the radiation shielding parameters of the elements/compounds/composites theoretically. Attempts are being made by a few researchers to update and develop software tools of these kinds. However, the efficacy of these tools in terms of their comparison is yet to be explored. Thus, an attempt has been made in the present study to compare & explore the best tool among the widely used and most trusted tools, such as Phy-X, XCOM, FFAST and XMuDat photon attenuation databases, to evaluate the shielding parameters of PVA-based composites filled with bismuth and tungsten, and also for materials such as bismuth, tungsten, gold, copper, platinum, lead and barite. Careful analysis of the data obtained computationally and experimentally shows that, although the Phy-X tool provides various shielding parameters with multiple choices in the selection of energy range, it is noticed that this tool needs to be figured out for obtaining the absorption edges of the composites of interest precisely. The XCOM database provides sharp absorption edges; however, this tool gives multiple values of mass attenuation coefficients corresponding to a particular absorption edge energy. On the other hand, The FFAST tool provides sharp absorption edges along with X ray fine structure. However, the tool restricts to work with elements and compounds in the energy range 1 keV–433 keV, which limits the utilization of this tool. Furthermore, the XMuDat tool has a limiting option to work with the materials available in its library/database and provides the mass attenuation coefficient and four other parameters. However, the XMuDat provides a large number of data points, which helps to identify any minute deviation in the values of the parameters. Therefore, the present study suggests that the XMuDat tool is much more advantageous and reliable than the other tools for the detailed study of various radiation shielding parameters.

Ionizing radiation is becoming increasingly prevalent in various applications on Earth and in space. This study evaluates the radiation shielding performance of five quaternary glass systems with different chemical compositions of 60SiO 2 -35Pb 3 O 4 -(5-x)ZnO-xWO 3 (0 ≤ x ≤ 5 mol%) using theoretical software and Monte Carlo simulations. The study calculates various shielding parameters, including attenuation coefficients, mean free path, half value layer, tenth value layer, effective atomic number, electron density, and build-up factors, for the photon energy range of 1 keV to 100 GeV. PZSW3 and PZSW5 show comparable attenuation coefficients at low and high energy levels, which are higher than the other selected samples. Additionally, PZSW5 has a neutron removal cross-section of 0.120 cm−1, slightly less than PZSW4's 0.122 cm−1 and greater than the other three samples. On average, PZSW5 (60SiO 2 -35Pb 3 O 4 -5WO 3) exhibits greater radiation attenuation than other samples and most of the compared 19 samples in terms of shielding parameters. The study also analyzes the trajectories of 10 5 photons in the system and finds that PZSW5 has the most effective radiation protection capability among the glass composites studied. [ABSTRACT FROM AUTHOR]

Soils are porous materials with high shielding capability to attenuate gamma and X-rays. The disposal of radionuclides throughout the soil profile can expose the living organisms to ionizing radiation. Thus, studies aiming to analyze the shielding properties of the soils are of particular interest for radiation shielding. Investigations on evaluating the shielding capabilities of highly weathered soils are still scarce, meaning that additional research is necessary to check their efficiency to attenuate radiation. In this study, the radiation shielding properties of contrasting soils were evaluated. The radiation interaction parameters assessed were attenuation coefficients, mean free path, and half- and tenth-value layers. At low photon energies, the photoelectric absorption contribution to the attenuation coefficient predominated, while at intermediate and high photon energies, the incoherent scattering and pair production were the dominant effects. Soils with the highest densities presented the best shielding properties, regardless of their chemical compositions. Increases in the attenuation coefficient and decreases in shielding parameters of the soils were associated with increases in clay, Fe2O3, Al2O3, and TiO2 amounts. In addition, this paper provides a comprehensive description of the shielding properties of weathered soils showing the importance of their granulometric fractions and oxides to the attenuation of the radiation.

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 (Δ 0.5), lead equivalent thickness (Δ eq) 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). • Gamma-ray protection features of clay bricks were investigated experimentally using NaI (Tl) spectrometry. • The physical parameters of clay brick are determined. • Synthetic bricks provide a lead-free, efficient solution for protection. [ABSTRACT FROM AUTHOR]

Lead silicate glasses are used to absorb electromagnetic waves. This work investigates the radiation shielding properties of a xSiO 2.(1-x)PbO 2 glass system containing 5 and 10 mol% of CaO and B 2 O 3. Analyses for characterization include XRD, SEM, EDAX, DRS (UV–Vis), and density analyses. Here, DRS (UV–Vis) analysis is used to investigate the absorption value in the range of 200–900 nm, and XCOM software is used to investigate the γ-ray wavelength. UV–Vis analysis specifies that the absorption value in the UV-ray wavelength increases by increasing the contents of CaO and B 2 O 3 , while the XCOM software shows that the absorption value in the γ-ray wavelength decreases with the addition of CaO and B 2 O 3. It seems that the effect of different oxides on the properties of lead silicate glasses is complex and depends on the position of the elements. The results show that glass transparency decreases with the addition of CaO and B 2 O 3. The mechanism of the addition of CaO and B 2 O 3 is discussed and compared with the results of other dopants such as ZnO and BaO in this glass. In this research, for the first time, the "inner-atomic" and "outer-atomic" perspectives are presented and discussed to justify the obtained results. • The radiation shielding properties of a xSiO 2.(1-x)PbO 2 glass system containing 5 and 10 mol% of CaO and B 2 O 3 has been investigated. • The e absorption value in the UV-ray wavelength has been increased by increasing the contents of CaO and B 2 O 3. • The glass transparency has been decreased with the addition of CaO and B 2 O 3. [ABSTRACT FROM AUTHOR]

The development of reinforced polymer composite materials has had a significant influence on the challenging problem of shielding against high-energy photons, particularly X-rays and γ -rays in industrial and healthcare facilities. Heavy materials' shielding characteristics hold a lot of potential for bolstering concrete chunks. The mass attenuation coefficient is the main physical factor that is utilized to measure the narrow beam γ -ray attenuation of various combinations of magnetite and mineral powders with concrete. Data-driven machine learning approaches can be investigated to assess the gamma-ray shielding behavior of composites as an alternative to theoretical calculations, which are often time- and resource-intensive during workbench testing. We developed a dataset using magnetite and seventeen mineral powder combinations at different densities and water/cement ratios, exposed to photon energy ranging from 1 to 100 6 kiloelectronvolt (KeV). The National Institute of Standards and Technology (NIST) photon cross-section database and software methodology (XCOM) was used to compute the concrete's γ -ray shielding characteristics (LAC). The XCOM-calculated LACs and seventeen mineral powders were exploited using a range of machine learning (ML) regressors. The goal was to investigate whether the available dataset and XCOM-simulated LAC can be replicated using ML techniques in a data-driven approach. The minimum absolute error (MAE), root mean square error (RMSE), and R 2 s c o r e were employed to assess the performance of our proposed ML models, specifically a support vector machine (SVM), 1d-convolutional neural network (CNN), multi-Layer perceptrons (MLP), linear regressor, decision tree, hierarchical extreme machine learning (HELM), extreme learning machine (ELM), and random forest networks. Comparative results showed that our proposed HELM architecture outperformed state-of-the-art SVM, decision tree, polynomial regressor, random forest, MLP, CNN, and conventional ELM models. Stepwise regression and correlation analysis were further used to evaluate the forecasting capability of ML techniques compared to the benchmark XCOM approach. According to the statistical analysis, the HELM model showed strong consistency between XCOM and predicted LAC values. Additionally, the HELM model performed better in terms of accuracy than the other models used in this study, yielding the highest R2score and the lowest MAE and RMSE. [ABSTRACT FROM AUTHOR]

The linear attenuation coefficient (LAC), mean free path (MFP), half-value layer (HVL), and the radiation protection efficiency (RPE) parameters of Lombok pumice powder from 3 different regions (Ijobalit, Setangi beach, and Lingsar) have been analyzed. The radiation parameter analysis was carried out to determine the pumice that potential as a raw material of radiation shielding composite. The Monte Carlo simulation using the GEANT4 toolkit was applied to analyze those parameters using a gamma-ray transmission measurement for the photon energies of 57Co, 133Ba, 54Mn, 137Cs, 60Co, 65Zn, 22Na and 40K. The GEANT4 simulation results were compared to the XCOM theoretical calculation and show that the linear attenuation coefficient parameter has a good agreement with the XCOM results based on the determination coefficient of the correlation graph (R² = 0.998) between those 2 approaches methods. Setangi beach pumice has a smaller LAC parameter than Ijobalit pumice and Lingsar pumice. The MFP and HVL parameter of the Setangi beach pumice indicate the absorption ability of gamma photons is low. In the low gamma energy 0.122 MeV, Ijobalit pumice and Lingsar pumice have more than 50 % RPE and are better used as a raw material of radiation shielding composite. [ABSTRACT FROM AUTHOR]

The study of radiation interaction parameters in complex materials (e.g., soils) has gained great importance in the last decades. However, few studies have directly addressed in detail how the radiation interaction is affected by the chemical and physical characteristics of soils, especially in tropical and subtropical climate regions like Brazil. The soil is an important material widely utilized in agriculture and engineering. Knowing this material radiation interaction properties is fundamental to understand its role in different areas of applied sciences such as radiation shielding, environmental monitoring, and geological characterization. This study presents a detailed analysis of how parameters like the atomic ( σ A ), molecular ( σ M ), and electronic ( σ E ) cross-sections are affected by the texture and chemical composition of soils. The effective atomic number ( Z eff ) and electron density ( N el ) were also investigated. Photon energies in the energy range from 10 to 1330 k e V were selected. The XCOM computer code was chosen to simulate the radiation interaction parameters. Five soils presenting different physical characteristics and oxide compositions were studied. The results show a strong dependence of the radiation interaction parameters on the elemental composition up to 100 k e V . After this photon energy, factors such as fractional abundance, for example, become important to discriminate the soils. The parameters σ A , σ E , and Z eff followed the same trend as that of the percentage of the oxides Fe 2 O 3 and TiO 2 among soils, while σ M and N el matched the oxides S i O 2 and Al 2 O 3 . Our results highlight that understanding how the chemical composition influences the radiation interaction in complex materials provides information that can be useful in areas such as radiation shielding and image analysis and processing, which are based on radiation interaction data. [ABSTRACT FROM AUTHOR]

Spine fixation is required in cases such as congenital spinal curvatures, vertebral fractures, sagittal collapse over time, painful kyphosis, and bone load due to tumors. Although there are many methods in the literature, the most commonly used spine fixation method is the fixation with pedicle screws. In these cases, it is known that pedicle screws are used frequently in the body. In this study, how the radiological exposure of the pedicle screws in the vertebral column that dose was evaluated by simulation methods. First, the elemental analysis of the pedicle screw was analyzed via Scanning Electron Microscopy (SEM) equipped with the Energy Dispersive X-ray Spectroscopy (EDS). Then, the elemental compositions of the pedicle screw obtained were used for simulation codes. subsequently, the half-value thickness and the attenuation coefficient calculations were conducted for the pedicle screw and vertebral column. Both XCOM software and MCNP (Monte Carlo N-Particle) simulation code were used to obtain photon interaction parameters within the energy range of 60-250 keV.

Abstract Background The Margin of Stability (MoS) is a widely used objective measure of dynamic stability during gait. Increasingly, researchers are using the MoS to assess the stability of pathological populations to gauge their stability capabilities and coping strategies, or as an objective marker of outcome, response to treatment or disease progression. The objectives are; to describe the types of pathological gait that are assessed using the MoS, to examine the methods used to assess MoS and to examine the way the MoS data is presented and interpreted. Methods A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA) in the following databases: Web of Science, PubMed, UCL Library Explore, Cochrane Library, Scopus. All articles measured the MoS of a pathologically affected adult human population whilst walking in a straight line. Extracted data were collected per a prospectively defined list, which included: population type, method of data analysis and model building, walking tasks undertaken, and interpretation of the MoS. Results Thirty-one studies were included in the final review. More than 15 different clinical populations were studied, most commonly post-stroke and unilateral transtibial amputee populations. Most participants were assessed in a gait laboratory using motion capture technology, whilst 2 studies used instrumented shoes. A variety of centre of mass, base of support and MoS definitions and calculations were described. Conclusions This is the first systematic review to assess use of the MoS and the first to consider its clinical application. Findings suggest the MoS has potential to be a helpful, objective measurement in a variety of clinically affected populations. Unfortunately, the methodology and interpretation varies, which hinders subsequent study comparisons. A lack of baseline results from large studies mean direct comparison between studies is difficult and strong conclusions are hard to make. Further work from the biomechanics community to develop reporting guidelines for MoS calculation methodology and a commitment to larger baseline studies for each pathology is welcomed.

This study investigates the effect of substituting boron oxide (B 2 O 3) with heavy metal oxides (HEMOs) on the structural, mechanical, and gamma-ray shielding properties of potassium borate (KB) glass systems. The glass compositions analyzed include 80B 2 O 3 –20K 2 O and 65B 2 O 3 –20K 2 O-15HEMO (where, HEMO = BaO, Bi 2 O 3 , or Pb 3 O 4). All samples were prepared using the melt-quenching method, and their amorphous nature was confirmed through X-ray diffraction (XRD). Fourier-transform infrared spectroscopy (FTIR) had revealed BO 3 , BO 4 , and BiO 6 groups beside the B– O –B linkages. The density increased with the addition of HEMOs, following the order: Pb 3 O 4 (KB4) > Bi 2 O 3 (KB3) > BaO (KB2) > and pure KB (KB1). This trend was also observed in the molar volume (Vₘ) and oxygen molar volume (Vₒ), while the oxygen packing density (P ρ) decreased. Mechanical properties assessed using the Makishima-Mackenzie model indicated that KB3 exhibited the highest elastic modulus (Yₘ) and Poisson's ratio (μ). The microhardness (Hₘ) followed the sequence KB2 > KB3 > KB4 > KB1, attributed to the higher bonding energy in KB2. Gamma-ray shielding parameters, including mass attenuation coefficients (MAC), were calculated using Phy-X and XCOM software for photon energies between 0.2835 MeV and 1.333 MeV. KB4 (Pb 3 O 4) showed superior shielding performance with the highest linear attenuation coefficient (LAC) and the lowest half-value layer (HVL) and mean free path (MFP). Despite KB4's high density, KB3 (Bi 2 O 3) is suggested as a more suitable candidate for radiation shielding applications due to its balanced combination of mechanical strength and γ-ray attenuation efficiency. • This study examines the impact of BaO, Bi 2 O 3 , and Pb 3 O 4 on KB glass properties. • Pb 3 O 4 -doped glass (KB4) showed the highest density and best γ-ray shielding. • Bi 2 O 3 -doped glass (KB3) displayed the best mechanical strength and solid radiation shielding. • Bi 2 O 3 -doped glass (KB3) combines strength and shielding, ideal for durable radiation protection. [ABSTRACT FROM AUTHOR]

Polimer betonların inşaat mühendisliği uygulamalarında kullanımı yüksek mukavemetlerinin yanı sıra çevresel etkilere ve sıvı temasına karşı geçirimsizlik özelliklerinden dolayı her geçen gün artmaktadır. Bu kapsamda üretilen polimer betonların farklı amaçlar için de kullanılabilirlikleri büyük öneme sahiptir. Bu çalışmada, polyester reçine ile hacimce %0, %15, %30 ve %45 oranlarında perlit ve pomza agregalarının karıştırılmasıyla üretilen polimer betonların radyasyon zırhlama performansları deneysel ve teorik olarak araştırılmıştır. Polimer betonların gama radyasyonu etkisi altındaki radyasyon zırhlama özellikleri deneysel olarak 60Co ve 152Eu radyoaktif kaynakları kullanılarak, teorik olarak ise XCOM programı ile hesaplanmış, her bir polimer beton numunesi için radyasyon zayıflatma katsayıları belirlenmiştir. Son olarak yapılan deneysel çalışmadan ve teorik hesaplamadan elde edilen bulguların birbirleri ile ilişkileri karşılaştırmalı olarak ele alınmış ve elde edilen bulguların birbirleri ile uyum içerisinde olduğu ortaya çıkmıştır.

This paper examines gamma-ray shielding properties of SBC-Bx glass system with the chemical composition of 40SiO2–10B2O3–xBaO–(45-x)CaO– yZnO– zMgO (where x = 0, 10, 20, 30, and 35 mol% and y = z = 6 mol%). Mass attenuation coefficient (μ/ρ) which is an essential parameter to study gamma-ray shielding properties was obtained in the photon energy range of 0.015–15 MeV using PHITS Monte Carlo code for the proposed glasses. The obtained results were compared with those calculated by WinXCOM program. Both the values of PHITS code and WinXCOM program were observed in very good agreement. The μ/ρ values were then used to derive mean free path (MFP), electron density (Neff), effective atomic number (Zeff), and half value layer (HVL) for all the glasses involved. Additionally, G-P method was employed to estimate exposure buildup factor (EBF) for each glass in the energy range of 0.015–15 MeV up to penetration depths of 40 mfp. The results reveal that gamma-ray shielding effectiveness of the SBC-Bx glasses evolves with increasing BaO content in the glass sample. Such that SBC-B35 glass has superior shielding capacity against gamma-rays among the studied glasses. Gamma-ray shielding properties of SBC-B35 glass were compared with different conventional shielding materials, commercial glasses, and newly developed HMO glasse. Therefore, the investigated glasses have potential uses in gamma shielding applications.

In this study, the shielding properties of (Y2O3)0.31−z(Al2O3)z(P2O5)0.69, where 0 ≤ z ≤ 0.31 , in glasses, have been examined to be applied in radiation protection applications. Therefore, we used the Monte Carlo simulation Geant4 code to simulate the mass attenuation coefficient for A, B, C, D, E, F glass samples prepared according to the formula (Y2O3)0.31−z(Al2O3)z(P2O5)0.69. The obtained simulated mass attenuation (µm) results were compared with those obtained theoretically by the XCOM database within photon energies 0.03–2 MeV. The simulated µm results were found to be in good agreement with the XCOM received data. The linear attenuation coefficients(µ), the effective atomic number (Zeff), the effective electron density (Neff), half-value layer (Δ0.5), and mean free path (MFP) were calculated based on the simulated µm. The µm was decreased with the increase of photon energy, and with the increase of (mol%) fraction of Y2O3, and the decrease of (mol%) fraction of Al2O3. It is found that the F glass with 0.364(wt.%)concentration of Y2O3 has superior gamma-ray shielding effectiveness due to its higher values of mass attenuation coefficient, effective atomic number, and electron densities, and lower values of Δ0.5 and MFP. Also, in this work, the neutron shielding ability of the selected glasses was determined. The effective removal cross-section Σ R (cm− 1) was calculated by using the Monte Carlo simulation Geant4 code. Finally, it is found that the B Glass with 0.173 (wt.%)concentration of Al2O3has better neutron shielding properties than the other selected glass samples; due to it has the highest value of effective removal cross-section and has the lowest value of HVL at energy 1MeV. [ABSTRACT FROM AUTHOR]

In this study, four basalt rocks were selected to produce continuous fibers, the chemical composition of basalt rocks and the corresponding fibers were compared using the XRF, the results reveal that the content of the chemical component present in the basalt fibers is consistent with basalt rocks. The mass attenuation coefficient of different fibers was analyzed using the XCOM program, the results indicate that when the incident electron energy is 0.01~0.1 MeV, fiber mass attenuation coefficient is found to be positively correlated with the content of Wt (Fe2O3 + MnO + TiO2 + CaO + K2O). The structure and properties of the fibers irradiated by different absorption doses of gamma rays were studied using the SEM, EDX and FTIR, the results indicate that irradiation produces no effect on the basalt fiber structure, surface morphology, and contents of the surface elements, the mass loss rate of the fiber was much less than 1%, fiber tensile strength and elastic modulus increased 4.7–7.5% and 3.9–9.1%, respectively, but the elongation at break of fiber decreased 4.18–10.97%. Two selected basalt fiber cloths of thickness 0.12 and 0.28 mm were irradiated with gamma rays of energies of 100 and 120 keV to examine the shielding property of basalt fibers against the gamma rays, when the energy was 100 keV, the shielding ratios of the fiber cloths were 18.9% and 22.5%, respectively, but when the energy was 120 keV, the shielding ratios of the fiber cloths decreased significantly and were at 8.7% and 10.4%, respectively. When the irradiated electron energy is 100 keV, the shielding ratio for basalt fiber cloths measuring 0.12 and 0.28 mm can reach up to 38.9% and 46.3% of that of the 0.5-mm lead plate, respectively. [ABSTRACT FROM AUTHOR]

This work numerically determined high-energy photon shielding properties of self-healing poly(vinyl alcohol) (PVA) hydrogels containing lead-free, heavy-metal compounds, namely, bismuth oxide (Bi2O3), tungsten oxide (WO3), and barium sulfate (BaSO4), through XCOM software packages. In order to understand the dependencies of the shielding properties of the hydrogels on filler contents and photon energies, the filler contents added to the hydrogels were varied from 0–40 wt.% and the photon energies were varied from 0.001–5 MeV. The results, which were verified for their reliability and correctness with those obtained from PHITS (Particle and Heavy Ion Transport code System), indicated that overall shielding performances, which included the mass attenuation coefficients (µm), the linear attenuation coefficient (µ), the half-value layer (HVL), and the lead equivalence (Pbeq), of the hydrogels improved with increasing filler contents but generally decreased with increasing photon energies. Among the three compounds investigated in this work, Bi2O3/PVA hydrogels exhibited the highest photon attenuation capabilities, determined at the same filler content and photon energy, mainly due to its highest atomic number of Bi and the highest density of Bi2O3 in comparison with other elements and compounds. Furthermore, due to possible reduction in self-healing and mechanical properties of the hydrogels with excessive filler contents, the least content of fillers providing a 10-mm sample with the required Pbeq value of 0.5 mmPb was investigated. The determination revealed that only the hydrogel containing at least 36 wt.% of Bi2O3 exhibited the Pbeq values greater than 0.5 mmPb for all photon energies of 0.05, 0.08, and 0.1 MeV (common X-ray energies in general nuclear facilities). The overall outcomes of the work promisingly implied the potential of PVA hydrogels to be used as novel and potent X-ray and gamma shielding materials with the additional self-healing and nonlead properties. [ABSTRACT FROM AUTHOR]

• Geant4 low energy photon models were updated using EPICS2017 database. • Cross-sections, scattering functions and form factors were considered. • Important improvement has been made on the parameterizations. • The simulation results using updated models were found in good agreement with XCOM. This paper describes in detail the implementation of Geant4 Livermore electromagnetic physics models based on the EPICS2017 database for the low energy transport of photons. These models describe four photon processes: gamma conversion, Compton scattering, photoelectric effect and Rayleigh scattering. New parameterizations based on EPICS2017 were performed for scattering functions of Compton effect, subshell cross-sections of the photoelectric effect and form factors of Rayleigh scattering, in order to improve the precision of fitted values compared to tabulated values. Comparisons between new and old parameterizations were also carried out to evaluate the precision of the new parameterizations. The models were tested through a comparative study, in which the mass attenuation coefficient was calculated for both total photon interaction and each process using Geant4 simulations based on EPICS2017 and EPDL97 respectively. The results obtained from the simulations were found in good agreement with the XCOM reference data. [ABSTRACT FROM AUTHOR]

ABSTRACT Use of soil in forensic science is related to its several chemical, physical, and biological properties associated with its capacity to adhere to different materials and surfaces. Forensic soil experts and police investigators have been using soil samples as an aid in criminal investigations. Soils can act as fingerprints because they present contrasting physical, chemical, biological, and mineralogical properties. However, depending on the analytical tools utilized to characterize the soil, differentiating the samples when they have similar properties might be impossible. Thus, soil utilization as a fingerprint material requires increasing the number of variables measured as well as the accuracy and precision of the measurements. This study presents the feasibility of methods based on X-ray fluorescence (XRF) and radiation interaction parameters to discriminate soils for forensic investigations. Analyses of soil particle size, elemental composition (XRF), mass attenuation coefficient (μ), atomic (σa) and electronic (σe) cross-sections, effective atomic number (Zeff), and electron density (Nel) were carried out to evaluate the potential of nuclear parameters to differentiate soils. Ten different soil types collected at 0.00-0.05 m layer were studied. The radiation interaction parameters were obtained through the XCOM computer code, while the experimental measurements were carried out by the traditional gamma-ray attenuation method utilizing the radioactive sources of 241Am and 137Cs. The results showed that the soils presented broad differences in terms of clay, silt, and sand contents as well as in the major oxides. These differences influenced the radiation attenuation properties as verified through the multivariate analysis. For the lowest photon energy studied (10 and 30 keV), σe was the most interesting parameter to discriminate the soils. For energies above 59.5 keV, Zeff and Nel were the most important parameters. Good agreement was found between the calculated and measured parameters. The findings of this study indicate that radiation interaction parameters have great potential for crime scene investigation providing new parameters for better discrimination of soils. The main advantage of the method presented here is that it is fast, easy to implement, does not require powerful computers, and the XCOM code can be run online at the NIST (National Institute of Standards and Technology, USA) website.

This research was conducted to study x-ray and gamma radiation shielding parameters such as mass attenuation coefficient, mean free path, half value layer, tenth value layer, effective atomic numbers, effective electron density for the xBi2O3-(95-x)B2O3-5BaO (where x = 20 mol%, 35 mol%, 50 mol%, and 70 mol%) glass systems with different molar composition. The studied ceramic specimens were denoted by BB20, BB35, BB50 and BB70 and their density values were 4.438 g/cm³, 5.973 g/cm³, 7.156 g/cm³, and 8.005 g/cm³, respectively. Radiation shielding parameters of the samples were investigated by using web based XCOM programme. The obtained results revealed that the highest mass attenuation coefficients were reported for BB70 sample, which has the highest Bi2O3 additive in its chemical structure. At 7 MeV photon energy, half value layer (HVL) values were reported as 5.7812 cm, 3.8065 cm, 2.8533 cm, and 2.2457 cm for BB20, BB35, BB50 and BB70, respectively. Therefore, It can be concluded that the present bismuth sesquioxide based glasses in the Bi2O3-B2O3-BaO glass system have a good quality in radiation protection purposes. Therefore, this glass system can be used as an alternative to conventional materials with the right molar compositon in its chemical formation. [ABSTRACT FROM AUTHOR]

The applicability of a simple Monte Carlo gamma transmission model was investigated by characterizing the mass attenuation coefficient, mean free path, and half-value layer for six glass sample simulants of the PbO-Li2O-B2O3 system previously prepared by others. The mass attenuation coefficients were calculated and compared with those of XCOM and the available experimental data for twenty gamma energy lines from 0.107 MeV to 7.12 MeV, and good agreement was obtained. The effects of PbO concentration on the simulated values of mass attenuation coefficient, mean free path, and half-value layer, were calculated and compared with available experimental data in the gamma energy range 0.356-1.332 MeV, and good agreement was found. The glass sample with the optimal gamma shielding for all considered gamma energies was the sample with the chemical formula Pb3B4O9. On the one hand, the Monte Carlo results confirm the applicability of the proposed model for performing additional calculations of photon attenuation properties for different glass compositions, and on the other hand, considering the energy range of gamma-ray photons in a reactor during uranium fission, 0.10-10 MeV, the results suggest the use of the studied glass samples as optical shielding windows in nuclear reactors. [ABSTRACT FROM AUTHOR]

In the last few decades, a lot of research has focused on the radiation interaction with complex materials such as soil. The mass attenuation coefficient (μ ) is important to analyze the different physical properties of porous media. For this reason, it is important to understand how μ varies as a function of the chemical composition of porous materials. This study analyzes the influence of the chemical composition on μ , from 1 to 1500 keV , using the XCOM computer simulation code. Five types of soil, containing variable proportions of SiO 2 , Al 2 O 3 , Fe 2 O 3 , and TiO 2 , were evaluated. The results showed that the influence of each of the partial effects (photoelectric, coherent, and incoherent scattering), in μ values, occurred from their dependence on the atomic number (Z ), with greater Z influence in low energies. A detailed analysis of the influence of the chemical composition considering the oxides individually is also presented. In addition, this paper brings a comprehensive description of the methodology employed for the measurements of the radiation interaction main effects and it can also be used to teach physics applied courses in areas such as modern physics, dosimetry, and radiation protection, among others. [ABSTRACT FROM AUTHOR]

The lower limb exoskeleton is playing an increasing role in enabling individuals with spinal cord injury (SCI) to stand upright, walk, turn, and so on. Hence, it is essential to maintain the balance of the human-exoskeleton system during movements. However, the balance of the human-exoskeleton system is challenging to maintain. There are no effective balance control strategies because most of them can only be used in a specific movement like walking or standing. Hence, the primary aim of the current study is to propose a balance control strategy to improve the balance of the human-exoskeleton system in dynamic movements. This study proposes a new safety index named Enhanced Stability Pyramid Index (ESPI), and a new balance control strategy is based on the ESPI and the Dynamic Movement Primitives (DMPs). To incorporate dynamic information of the system, the ESPI employs eXtrapolated Center of Mass (XCoM) instead of the center of mass (CoM). Meanwhile, Time-to-Contact (TTC), the urgency of safety, is used as an automatic weight assignment factor of ESPI instead of the traditional manual one. Then, the balance control strategy utilizing DMPs to generate the gait trajectory according to the scalar and vector values of the ESPI is proposed. Finally, the walking simulation in Gazebo and the experiments of the human-exoskeleton system verify the effectiveness of the index and balance control strategy.

The lower limb exoskeleton is playing an increasing role in enabling individuals with spinal cord injury (SCI) to stand upright, walk, turn, and so on. Hence, it is essential to maintain the balance of the human-exoskeleton system during movements. However, the balance of the human-exoskeleton system is challenging to maintain. There are no effective balance control strategies because most of them can only be used in a specific movement like walking or standing. Hence, the primary aim of the current study is to propose a balance control strategy to improve the balance of the human-exoskeleton system in dynamic movements. This study proposes a new safety index named Enhanced Stability Pyramid Index (ESPI), and a new balance control strategy is based on the ESPI and the Dynamic Movement Primitives (DMPs). To incorporate dynamic information of the system, the ESPI employs eXtrapolated Center of Mass (XCoM) instead of the center of mass (CoM). Meanwhile, Time-to-Contact (TTC), the urgency of safety, is used as an automatic weight assignment factor of ESPI instead of the traditional manual one. Then, the balance control strategy utilizing DMPs to generate the gait trajectory according to the scalar and vector values of the ESPI is proposed. Finally, the walking simulation in Gazebo and the experiments of the human-exoskeleton system verify the effectiveness of the index and balance control strategy. [ABSTRACT FROM AUTHOR]

In this work, we synthesized waste CRT-derived glass systems doped with varying amounts of CoO for understanding the radiation shielding abilities. For achieving this, the glass system of xCoO—(100-x)CRTs (x: 0, 2.5, 5., 7.5, and 10 wt%) was designed, and Co0 to Co10 glass series were fabricated via traditional melt quenching technique. According to the physical measurements, the undoped sample, Co0, showed a transparent appearance under ambient light, whereas the samples containing CoO displayed an opaque view. Additionally, the Co0 sample had a density value of 2.8828 g. cm−3 while Co2.5 to Co10 samples achieved 2.9542, 3.0261, 3.1423, and 3.2214 g. cm−3, respectively. On the other hand, Vm values were found to be 24.16, 23.62, 23.10, 22.29, and 21.78 cm−3. mol−1 for the glass series from Co0 to Co10 in the respective order. Within the context of radiation shielding features, spectroscopic measurements were carried out at 662, 1173, and 1332 keV gamma-ray energies. We found out that the LAC linearly increased with the increasing CoO rate in the glass. Further, the experiments and calculations (XCOM) revealed a good agreement with each other. The experimental results of the LAC ranged from 0.1437 cm−1(for Co0 at 1332 keV) to 0.3214 cm−1 (for Co10 at 662 keV). Based upon LAC values, other essential parameters such as mean free path (mfp), half-value layer (HVL), and tenth value layer (TVL) were assessed, and we obtained that all three parameters were in decreasing trend as a function of increasing CoO insertion ratio. In conclusion, one can valorize waste CRT glasses contained with CoO substance for radiation shielding applications. [ABSTRACT FROM AUTHOR]

New glass systems of bismuth borate with various concentrations of cadmium oxide are prepared based on the melt‐quenching method. The X‐ray diffraction (XRD) reveals a fully amorphous structure of the prepared glasses (S1–S4), and the UV–vis results display good transparency (>50%) in the visible and near‐UV region. In addition, the radiation shielding properties (mass attenuation coefficient, half‐value layer, tenth value layer, mean free path, effective atomic number, and electron density) of the new glass system are determined at selected energies experimentally and by using MCNP5 simulation code and XCOM computer program. Based on the calculated relative difference, the obtained values from MCNP5 and XCOM are in good agreement with the experimental data. The mean free path of the current systems (particularly S4) shows optimistic results when compared with the barite and chalcocite concretes. [ABSTRACT FROM AUTHOR]

In this work, the attenuation capability of new Borate-based-glass system reinforced with titanium oxide containing PbO, CaO, TiO 2 and B 2 O 3 with different percentages was determined. Four different glass samples were synthesized by experimental technique using high pure germanium detector at different gamma ray sources using narrow beam method. The experimental method was verified by XCOM software. The values of the two methods were close and the relative deviation was satisfactory (less than 5 %) for all gamma energies (0.060, 0.662, 1.173 and 1.333 MeV). The highest linear attenuation coefficient (LAC) values achieved at low radiation energy of 0.0595 MeV. The Highest LAC values were 13.64, 13.97, 14.32 and 14.67 cm−1 for samples PCBT-1, PCBT-2, PCBT-3 and PCBT-4 in the same order, respectively. Conversely, the lowest LAC values in the examined energy range were found at 1.333 MeV. The lowest LAC values were 0.259, 0.266, 0.272 and 0.279 cm−1 for the aforementioned glasses, respectively. At 0.662 MeV, the transmission factor (TF) values decreases as 64.18, 63.54, 62.88 and 62.19 % as TiO 2 content increases as 5, 10, 15 and 20 mol % in the same order, respectively. The decreases in TF values was linked to an observable increase in the radiation protection efficiency (RPE). The increase in RPE with the increase of TiO 2 content confirms that the addition of TiO 2 leads to an improvement in the radiation shielding performance for the prepared glasses. • New borate based glasses were prepared for radiation shielding. • The experimental method was verified by XCOM software. • The highest LAC values achieved at 0.0595 MeV, varied between 13.64 and 14.67 cm−1. • The addition of TiO2 causes an increase in the RPE. [ABSTRACT FROM AUTHOR]

Concrete provides a superior shielding effect against γ-rays and neutron by reducing the radiation exposure to biological entities and their surroundings. A suitable amount of additives in the concrete mixture can enhance the shielding effect. With this perception, the mixing proportion of concrete has been prepared with different amounts of WC and B4C additives. The shielding effect of prepared concretes with WC and B4C additives have been investigated using experimental data (for 60Co and 252Cf sources), and theoretical prediction using codes MCNP6, XCOM, Auto-Zeff, and NXcom. Different shielding parameters such as; mass attenuation coefficient (μm), effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), and effective removal cross-section (ΣR) were calculated in the present work. The obtained experimental and MCNP6 results for γ-rays (μm) and neutron (ΣR) are in decent agreement with the difference of less than 6.5% and 8%, respectively. The outcomes of the present work show that the modified compositions have more advantages as compared to the pristine concrete. These also revealed that shielding parameters strongly depend on the atomic composition and density of additives of the prepared concrete. Hence, it has been demonstrated that the addition of an appropriate amount of WC and B4C to concrete may be an alternative option that can be used in several radiation protection applications.

This research work presents the preparation of ethylene-propylene-diene-monomer (EPDM) composites filled with different concentrations of lead oxide (PbO) and magnetite (Fe3O4). The catalytic role of Fe3O4 on peroxide vulcanisation was studied. The morphological studies were done by the FESEM analysis. The evaluation of gamma shielding ability of synthesised composites was done for 59.54 keV gamma rays using a gamma spectrometer. Various shielding parameters, such as percentage attenuation (%Att), linear attenuation coefficient (μ), relaxation length (λ), half value (HVL) and tenth value layer (TVL) thickness, were evaluated for synthesised composites. The obtained results showed that, the shielding ability of the synthesised composites increases with an increase in PbO concentration. Also, the thermal stability of the synthesised composites was studied by TGA and it was found that thermal stability of the synthesised composites decreases with an increase in PbO concentration. Thus by comparing the results of radiation shielding ability and thermal stability, EPDM, with 40 phr PbO and 20 phr Fe3O4, can be considered as an ideal shielding material among the synthesised composites. [ABSTRACT FROM AUTHOR]

Background: The Margin of Stability (MoS) is a widely used objective measure of dynamic stability during gait. Increasingly, researchers are using the MoS to assess the stability of pathological populations to gauge their stability capabilities and coping strategies, or as an objective marker of outcome, response to treatment or disease progression. The objectives are; to describe the types of pathological gait that are assessed using the MoS, to examine the methods used to assess MoS and to examine the way the MoS data is presented and interpreted.Methods: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA) in the following databases: Web of Science, PubMed, UCL Library Explore, Cochrane Library, Scopus. All articles measured the MoS of a pathologically affected adult human population whilst walking in a straight line. Extracted data were collected per a prospectively defined list, which included: population type, method of data analysis and model building, walking tasks undertaken, and interpretation of the MoS.Results: Thirty-one studies were included in the final review. More than 15 different clinical populations were studied, most commonly post-stroke and unilateral transtibial amputee populations. Most participants were assessed in a gait laboratory using motion capture technology, whilst 2 studies used instrumented shoes. A variety of centre of mass, base of support and MoS definitions and calculations were described.Conclusions: This is the first systematic review to assess use of the MoS and the first to consider its clinical application. Findings suggest the MoS has potential to be a helpful, objective measurement in a variety of clinically affected populations. Unfortunately, the methodology and interpretation varies, which hinders subsequent study comparisons. A lack of baseline results from large studies mean direct comparison between studies is difficult and strong conclusions are hard to make. Further work from the biomechanics community to develop reporting guidelines for MoS calculation methodology and a commitment to larger baseline studies for each pathology is welcomed. [ABSTRACT FROM AUTHOR]

As radiation is an essential tool in various technological applications, searching for a suitable shield is an urgent demand to minimize its damaging effects on human beings. In this research article, we report on the radiation shielding properties of some commercially available polymers namely poly(N‐isopropylacrylamide), polyethylene terephthalate, polystyrene, and polycarbonate (denoted by P1, P2, P3, and P4, respectively). The gamma ray attenuation parameters are calculated using the Geant4 simulation, PHITS code, and XCOM program. Half value layer (HVL), linear attenuation coefficient (LAC), gamma dose rate at different energy levels, mean free path (MFP), specific gamma ray constant, effective atomic number (Zeff) and effective electron density (Neff), removal cross section for fast neutron, and total cross section for thermal neutron are investigated at energies of 0.01, 0.03, 0.05, 0.07, and 0.1 MeV. The results indicate that the highest LAC values were observed for P2 polymer at 0.1 MeV, while the lowest LAC values were noted for P3 polymer at 0.01 MeV among the studied commercial polymers. The total cross sections of thermal neutrons for the investigated polymers change from 24.0717 to 31.8611 cm−1. Moreover, the MFPs and HVLs of the investigated polymers were very close to those of ordinary concrete and RS‐253‐G18 commercial glass, especially at the low energies. This suggests the utility of using the present polymer samples for shielding applications against gamma and/or neutron radiations. [ABSTRACT FROM AUTHOR]

Abstract The purpose of this research was to discriminate soil fractions using mineralogical and elemental analyses and to show those fractions that present greater contribution to the soil mass attenuation coefficient (μ) as well as their partial cross-sections for photoelectric absorption (PA), coherent scattering (CS) and incoherent scattering (IS). Soil samples from different places of Brazil classified as Yellow Argisol, Yellow Latosol and Gray Argisol were submitted to elemental and mineralogical analyses through energy dispersive X-ray fluorescence (EDXRF) and Rietveld Method with X-ray diffraction data (RM-XRD). The mixture rule was utilized to calculate μ of each soil. The EDXRF analysis showed as predominant elements Si, Al, Fe and Ti oxides. The highest contents were Si (914.3 to 981.3 g kg-1) in the sand fractions, Al (507.9 to 543.7 g kg-1) and Fe (32.5 to 76.7 g kg-1) in the clay fractions, and Ti (18.0 to 59.0 g kg-1) in the silt fractions. The RM-XRD allowed identifying that the sand fractions are predominantly made of quartz (913.3 to 995.0 g kg-1), while the clay greatest portion is made of kaolinite (465.0 to 660.6 g kg-1) and halloysite (169.0 to 385.0 g kg-1). The main effect responsible for μ was IS (50 to 61.4%) followed by PA (28 to 40.1%) and CS (9.9 to 10.6%). By using the principal component analysis (PC-1: 57.5% and PC-2: 20.9%), the samples were differentiated through the discrimination between physical, chemical and mineralogical properties. The results obtained suggest that general information about the radiation interaction in soils can be obtained through the elemental and mineralogical analyses of their fractions.

Dense glasses in the binary bismuth-borate system, x Bi 2 O 3 -(1- x)B 2 O 3 (BBO), x = 0.25, 0.5, & 0.75 were prepared by conventional melt-quenching process at different temperatures. The melt was hot pressed between the stainless-steel plates to obtain dense glasses. The glasses obtained were optically clear, thermally stable and amorphous in nature. Transparent BBO glasses exhibited high density in the range of 5.5–8.29 g/cm3 which is attributed to the high bismuth content and pressure induced compaction at high temperatures in the hot-pressed quenching. Gamma radiation shielding properties of the dense BBO glasses were investigated by calculating mass attenuation coefficients, effective atomic number, and different buildup factors. Radiation shielding properties were calculated using the XCOM and Phy-X web software as a function of photon energy for all the glasses. Experimental mass-attenuation coefficients at different energies of the BBO glasses were determined through radiation transmission method. Measured mass-attenuation coefficients of the BBO glasses were in close agreement with the calculated values. Further, exposure and energy absorption buildup factors of the dense BBO glasses were studied at different penetration depths as a function of the photon energy. The results were compared with the heavy-metal oxide glasses reported in the literature and with respect to lead metal shield. Dense binary bismuth glass exhibited high mass-attenuation coefficients, and low half-value layer, and mean-free path which are comparable with the metal lead. The dense binary bismuth borate glasses reported here can be the excellent radiation shielding transparent simple glass system and promising for the radiological applications. [ABSTRACT FROM AUTHOR]

An attempt has been made to prepare the nonlead-based gamma shielding materials by adding different weight percentages (0%, 10%, 20%, and 40%) of bismuth in high-density polyethylene (HDPE) matrix. Gamma shielding parameters such as linear attenuation coefficient (μ), mass attenuation coefficient (μm), half-value layer, tenth value layer relaxation length (λ), and percentage attenuation were determined for all synthesized samples using 3“×3” NaI (Tl) detector for 59.54 keV energy. The results obtained from attenuation studies have shown that the shielding efficiency of synthesized HDPE+Bi composites increases with an increase in the weight percentage of bismuth. The experimentally obtained mass attenuation coefficient values are compared with Monte Carlo simulation using Monte Carlo N-particle code and XCOM code and are in good agreement with each other. The mechanical parameters such as tensile strength, tensile modulus, and elongation at the break were also determined for synthesized composites. Among the prepared composites, HDPE containing 40 wt% of bismuth (HDPE+40% Bi) has shown good radiation shielding property for 59.54 keV gamma rays along with good mechanical properties. Therefore, HDPE+40% Bi can be considered as a better lead-free shielding material for low-energy gamma rays.