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In this research, we have a theoretical simple and highly sensitive sodium chloride (NaCl) sensor based on the excitation of Tamm plasmon resonance through a one-dimensional photonic crystal structure.

BACKGROUND: Understanding the fracture mechanics of bone is very important in both the medical and bioengineering field. Bone is a hierarchical natural composite material of nanoscale collagen fibers and inorganic material. OBJECTIVE: This study investigates and presents the fracture toughness of bovine cortical bone by using elastic plastic fracture mechanics. METHODS: The J-integral was used as a parameter to calculate the energies utilized in both elastic deformation (Jel) and plastic deformation (Jpl) of the hipbone fracture. Twenty four different types of specimens, i.e. longitudinal compact tension (CT) specimens, transverse CT specimens, and also rectangular unnotched specimens for tension in longitudinal and transverse orientation, were cut from the bovine hip bone of the middle diaphysis. All CT specimens were prepared according to the American Society for Testing and Materials (ASTM) E1820 standard and were tested at room temperature. RESULTS: The results showed that the average total J-integral in transverse CT fracture specimens is 26% greater than that of longitudinal CT fracture specimens. For longitudinal-fractured and transverse-fractured cortical specimens, the energy used in the elastic deformation was found to be 2.8–3 times less than the energy used in the plastic deformation. CONCLUSION: The findings indicate that the overall fracture toughness measured using the J-integral is significantly higher than the toughness calculated by the stress intensity factor. Therefore, J-integral should be employ to compute the fracture toughness of cortical bone.

In a bid to expand the amount of information available on glass systems and their potential applications for radiation shielding design, glass samples with the compositions (30-x)SrO-xAl2O3–68B2O3–2V2O5(x = 5, 7.5, 10, 12.5&15 mol %) coded as SABV0 - 4 were prepared by the melt-quenching technique and analyzed for their optical, structural, physical, and radiation shielding features. The glassy (amorphous) nature of the SABV glass samples was affirmed by broad peaks of X-ray diffraction spectra. Calculated values of density and molar volume shown opposite behavior and the variation of these values were discussed as structural modifications in the glass matrix. From recorded optical absorption spectra optical band gap energy (Eg)-indirect transition, Urbach energy and optical basicity were estimated. FTIR spectra were recorded for all the samples in the range 400 cm−1 to 4000 cm−1. The FTIR absorbance spectra unveiled the SABV network structure mainly incorporating of BO3 and BO4 units. Raman spectroscopy is achieved to detect the structural changes and at higher wavenumber, B–O stretching modes in [BO3] observed with one or two NBO's. The results of ESR spectra of glasses have indicated the highly covalent environment of vanadium ions. Analysis of the photon shielding parameters of the glasses which were obtained primarily from FLUKA Monte Carlo simulations and XCOM computations revealed photon energy and glass chemical composition dependence. The mass attenuation coefficient and effective atomic number ranged from 0.2668 to 0.3385 cm2g-1 and 12.98–15.93 accordingly as the weight fraction of Sr increased from 16.06 to 26.72% in the glasses. Generally, photon shielding ability of the SABV glasses follows the trend: SABV0 > SABV1 > SABV2 > SABV3 > SABV4. The thermal neutron total cross section follows the same trend with values fluctuating between 71.9553 and 80.6268 cm−1. However, SABV1 showed superior fast neutron moderating capacity among the glasses. The present SABV glasses showed outstanding photon shielding ability compared to common shields. The prepared glasses are thus suitable candidates for radiation protection applications.

Ion beam-induced luminescence (IBIL) is a versatile technique used to elucidate the chemical bond’s nature and analyze the defects study and impurities present in the material. In this study, IBIL spectra of phosphorus-irradiated sapphire has been analyzed under 2 MeV proton beam as a function of ion dose ranging from 1 × 1014 to 10 × 1014 ions/cm2 at room temperature in the wavelength range of 200–1,000 nm. The IBIL spectrum shows three kinds of luminescence features. The bands centered at 419 nm as F center and 330 nm as F+ center are associated with oxygen vacancies. The third kind of luminescence feature located at 704 nm is related to chromium impurities present in the crystal. The luminescence spectrum of the phosphorus-irradiated sapphire has been correlated with the spectrum obtained from pristine sapphire. The finding indicates that the intensity of defects due to phosphorus irradiation is reduced. As the proton ion fluence increases, the F and F+ center luminescence intensity eventually varies; it turns out that in phosphorus-irradiated sapphire, single crystal defects were reduced and the optical quality was improved.

Purpose This paper aims to numerically solve fully developed laminar flow in trapezoidal ducts with rounded corners which result following forming processes. Design/methodology/approach A two-dimensional model for a trapezoidal duct with rounded corners is developed and conservation of momentum equation is solved. The flow is assumed to be steady, fully developed, laminar, isothermal and incompressible. The key flow characteristics including the Poiseuille number and the incremental pressure drop have been computed and tabulated for a wide range of: sidewall angle (θ); the ratio of the height of the duct to its smaller base (α); and the ratio of the fillet radius of the duct to its smaller base (β). Findings The results show that Poiseuille number decreases, and all the other dimensionless numbers increase with increasing the radii of the fillets of the duct; these effects were found to amplify with decreasing duct heights or increasing sidewall angles. The maximum axial velocity was shown to increase with increasing the radii of the fillets of the duct. For normally used ducts in hydrogen fuel cells, the impact of rounded corners cannot be overlooked for very low channel heights or very high sidewall angles. Practical implications The data generated in this study are highly valuable for engineers interested in estimating pressure drops in rounded trapezoidal ducts; these ducts have been increasingly used in hydrogen fuel cells where flow channels are stamped on thin metallic sheets. Originality/value Fully developed laminar flow in trapezoidal ducts with four rounded corners has been solved for the first time, allowing for more accurate estimation of pressure drop.

This work deals with the study of the influence of adding AgI content on the physicochemical properties of (0.5As2Se3–0.5GeTe)100−x(AgI)x chalcohalide glassy system. The molar volume, excess volume, packing density, and compactness were determined. The number of coordination (average), number of constraints, cross-linking density as well as mean bond energy were computed and were found to decrease by adding AgI content. Floppy modes and average single bond energy were found to decrease. A linear relationship linking the heat of atomization to the cohesive energy was proved. Different estimates showed that the optical band gap decreased, and good agreement was found with the experimental results. The results of these estimates were used to determine the positions of the valence and conduction bands. The study also explains the interdependence between physiochemical properties and the optical band gap.

Tellurite glass is a model material having superior features for several applications. It can be considered as a potential host matrix for different oxides, and this paper aims to study the effects of TeO2/B2O3 substitution on synthesis, physical, optical and radiation shielding properties of ZnO–Li2O-GeO2-Bi2O3 glasses produced by melt quenching technique. The physical and optical features of the fabricated glasses were experimentally investigated by determining pivotal parameters such as density, XRD, tellurium ion concentration (Ni), linear refractive index (no), polaron radius (rp) and inter nuclear distance (ri). Moreover, the relative radiation deposition within the glasses was assessed via the attenuation coefficients (e.g. MAC), specific gamma ray constant (ᴦ), total stopping power (TSP), neutron cross sections, and dose rate (D). Our results suggest that both TeO2 and B2O3 additives have a significant effect on the fundamental properties of the ZnO–Li2O-GeO2-Bi2O3 glasses. It also found that the lower thicknesses of the present glasses are required to provide the same level of shielding than ordinary, ilmenite, steel scrap, hematic-serpentine, ilmenite-limonite and basalt-magnetite concretes, RS253-G18 and RS360 glass shields. Therefore, presently investigated glasses are promising photon shields in different technological applications of gamma- and x-rays.

The glass system was fabricated using traditional procedures. Fourier Transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), and radiation techniques were used to characterize the glasses. In an experiment, XRD was used to assess the system’s amorphous state. As the density of the manufacturing glasses rises, the molar volume declines. Borosilicate network is unaffected due to incorporation of BaO. With incorporation of BaO, FTIR results show a conversion from BO3 to BO4. The gamma ray shielding constraints were defined using the Phy-X software. Finally, adding BaO to the glass network improved the gamma shielding characteristics. As a result, this glass system should be used to shield against radiation.

In this article, author investigate the mechanical characteristics of examined glasses and glass–ceramics by replacing Li2O for Y2O3. X-ray diffraction revealed the glasses' amorphous nature. FT-IR analysis revealed that as replacing Li2O for Y2O3, increase in bridging oxygens (BOs), whereas non-bridging oxygens are declining. By increasing the Y2O3 content, the mechanical characteristics of the investigated glasses can be improved. This improvement is correlated with enhanced rigidity of the glass matrix, which is accountable for the increment in both packing density and Y–O bond strength. The author discovered that when Li2O is substituted for Y2O3, the thermal variables, hardness, and elastic moduli of glasses and glass–ceramics increment. XRD analysis of crystalline phase of studied glasses demonstrates all the predicted phases. In this article, Y2O3 is described as a strong nucleating agent capable of causing crystallization and supporting in the establishment of glass–ceramic phases.

Tellurite glass systems become an essential component for several medical and nuclear technologies. Radiation shielding characteristics of a newly developed tellurite glasses containing Sb2O3 and V2O5 in energy range from 0.1 to 10 MeV are reported in this work. A FLUKA simulation along with a suitable theoretical model is carried out to examine the shielding performance of the involved glass system against gamma, neutron, and charged-particles radiations. HVLs of the TSP glasses vary in order of TSP-D

The glass system 22SiO2- 23Bi2O3-37B2O3-13TiO2 $$-(5-x)$$ LiF- $$x$$ BaO $$, (0\le x\le 5) \text{m}\text{o}\text{l}.\text{\%}$$ . was fabricated using melt-quenching techniques. X-ray diffraction and ultrasonic techniques were used to characterize the glasses. X-ray diffraction patterns were used to prove that fabricated glasses are amorphous. The impacts of incorporating BaO on the composition dependence of the elastic characteristics of fabricated samples were explained. Density of the manufacture glasses increment, and molar volume reduced. The elastic moduli were investigated experimentally then compared using theoretical arguments. Makishima – Mazinize model were used to determine the elastic moduli theoretically for fabricated samples. Elastic moduli increase with BaO, and experimental and theoretical elastic moduli are in good agreement. Deviation values between elastic moduli (both experimentally and theoretically) were estimated. All the experimental variations values of elastic moduli of fabricated glasses were increment as BaO increased. Latent heat of melting, diffusion constant, and Gruneisen factor have been used to link the mechanical and thermodynamic characteristics of manufactured glass.

Using melt-quenching techniques, the glass system 22SiO2- 23Bi2O3-37B2O3-13TiO2 $$-(5-x)$$ LiF- $$x$$ BaO was prepared. The amorphous status of fabricated samples were established using X-ray diffraction patterns. Differential thermal analysis (glass transition temperature, crystallization temperature, and thermal stability) as well as optical properties (molar refractivity, bandgap, molar polarizability, reflection loss, metallization, electronegativity, and electron polarizability) of these glasses have been investigated. These structural changes influence the thermal properties, as we discovered. Indeed, as BaO levels rise, all the thermal parameters rise as well. With increasing BaO content, density, and refractive index rise. Bandgap energies for direct and indirect transitions reduced as the BaO content increased while Urbach energy increases. This interpretation attributable to the increment in the bond length of Ba-O. This study suggests that the fabricated glasses’ optical and thermal characteristics have improved, making them suitable for a variety of applications.

In this work, the Klein–Nishina (K–N) approach was used to evaluate the electronic, atomic, and energy-transfer cross sections of four elements, namely, zinc (Zn), tellurium (Te), barium (Ba), and bismuth (Bi), for different photon energies (0.662 MeV, 0.835 MeV, 1.170 MeV, 1.330 MeV, and 1.600 MeV). The obtained results were compared with the Monte Carlo method (Geant4 simulation) in terms of mass attenuation and mass energy-transfer coefficients. The results show that the K–N approach and Geant4 simulations are in good agreement for the entire energy range considered. As the photon energy increased from 0.662 MeV to 1.600 MeV, the values of the energy-transfer cross sections decreased from 81.135 cm2 to 69.184 cm2 in the case of Bi, from 50.832 cm2 to 43.344 cm2 for Te, from 54.742 cm2 to 46.678 cm2 for Ba, and from 29.326 cm2 to 25.006 cm2 for Zn. The obtained results and the detailed information of the attenuation properties for the studied elements would be helpful in developing a new generation of shielding materials against gamma rays.

This work aims to test the effectiveness of newly developed DFT-1/2 functional in calculating the electronic and optical properties of inorganic lead halide perovskites CsPbBr3. Herein, from DFT-1/2 we have obtained the direct band gap of 2.36 eV and 3.82 eV for orthorhombic bulk and 001-surface, respectively. The calculated energy band gap is in qualitative agreement with the experimental findings. The bandgap of ultra-thin film of CsPbBr3 is found to be 3.82 eV, which is more than the expected range 1.23-3.10 eV. However, we have found that the bandgap can be reduced by increasing the surface thickness. Thus, the system under investigation looks promising for optoelectronic and photocatalysis applications, due to the bandgap matching and high optical absorption in UV–Vis (Ultra violet and visible spectrum) range of electro-magnetic(em) radiation.

A safe radiation dose from computed tomography (CT) is normally specified through the Computed Tomography Dose Index (CTDI) as an “effective dose.” Radiation exposure from CT is relatively high in comparison with other radiological tests. In this paper, we evaluate doses used on adult patients during typical CT scans, in Al Jouf, the northern region of Saudi Arabia. Scanning processes were taken place in different parts of the body; including the pelvis, head, abdomen, and chest. The dose indices were calculated using the CT-expo v2.5 computer software. A comparison of the results with similar investigations, regionally and globally, was made. Other comparisons between displayed and calculated dose indices were also performed. The main values of CT volume are the dose index (CTDIvol) and dose-length product (DLP). The effectiveness results for head CTs were 45.0 mGy, 488 mGy.cm, and 5.2 mSv; while for pelvic CTs they were 16.4 mGy, 391 mGy.cm, and 4.0 mSv; whereas for abdominal CTs they were 22.2 mGy, 613 mGy.cm, and 6.5 mSv; finally they were 17.5 mGy, 380 mGy.cm, and 3.9 mSv for chest CTs. It is confirmed that the values obtained are within the internationally accepted values, except for the values of the head examination, in which the effective dose value of 5.2 mSv was higher than the recommended value. This work gives an overview of the doses received by adult patients during regular CT examination. It is the first regional CT dose survey and provides a baseline for improvement and quality control in the region of Al Jouf.

This paper focuses on the elastic properties and radiation shielding ability of ZnO–P2O5/B2O3 glass system containing six samples named as ZBP1, ZBP2, ZBP3, ZBP4, ZBP5, and ZBP6. For ZBP1, ZBP2, ZBP3, and ZBP4 samples, we investigated the influence of ZnO/P2O5 substitution (with absence of B2O3), while the effect of P2O5/B2O3 substitution was studied and discussed for ZBP5, and ZBP6 samples. The findings indicate that the Young′s modulus (Eth) as well as Bulk modulus (Kth) and Shear modulus (Sth) increased under both the ZnO/P2O5 substitution and the P2O5/B2O3 substitution. The values of gamma constant (Γ) rise with growing energy levels and the highest Γ was observed around 10 MeV and they were of 111,33, 111,83,116,60,119,69,119,86,120,57 R.m2/Ci.h for the investigated glasses of ZBP1- ZBP2- ZBP3- ZBP4- ZBP5 and ZBP6, respectively. The stopping power (SP) for electron was around 3.30 MeV cm2/g at the energy of 0.1 MeV for all of the involved glasses. The maximum cross section for fast neutron was observed for ZBP6 with the value of 0.11432 cm−1. The ZBP6 sample has the best properties among the other investigated samples for shielding applications.

This research article focuses on the significant role of Tb2O3 content on the optical properties and radiation shielding performance of Ga2O3–B2O3–Al2O3–GeO2 glasses named as GBAGT1, GBAGT2, GBAGT3, and GBAGT4 for Tb2O3 of 14, 18, 22 and 25 mol%, respectively. The findings of the optical study indicate that the optical dielectric constant of the present samples increased from 1.85 to 2.06 as the Tb2O3 content increased from 14 to 25 mol%. The results of the radiation shielding confirm that increasing Tb3+-dopant content in GBAGT4 increased its specific gamma ray constant (Γ) values over all other glass samples in the whole energy region. With increasing electron energy, the mass stopping power decreased for all samples and reached the minimum 1.372 and 1.327 (MeV cm2/g) for BGAGT1, BGAGT4, respectively, at 1 MeV electron energy. For a beam of neutrons of 0.1 meV, the total cross section in GBAGT1, GBAGT2, GBAGT3, and GBAGT4 was 294.54, 312.88, 317.24 and 311.69 (cm−1), respectively. The smallest MFP values of GBAGT4 glass sample in all energy regions confirm the superior shielding performance of the studied glass sample among other shielding materials namely traditional concrete and commercial polymers/glasses.

One of the important ways to the efficiently use of low-grade thermal energy is the adsorption refrigeration technology. However, it has some drawbacks such as low specific cooling power and coefficient of performance, especially under using the conventional adsorption pairs. Therefore, new adsorption pairs are tested in solar adsorption ice-maker and compared with other conventional pairs data from open literature to find the tendency of improving the solar adsorption ice-maker performance. The experimental test rig has been built in Upper Egypt in Qena City. Four different new adsorption pairs of granular activated carbon/R-410A, granular activated carbon/R-511A, Maxsorb III/R-410A, and Maxsorb III/R-511A are used. It is demonstrated that Maxsorb III/R-511A pair based solar adsorption ice-maker produced the highest values for specific cooling power, coefficient of performance, and ice production per 1 kg of adsorbent of approximately 226.7 W/kgads, 0.197, and 1.96 kg/kgads, respectively. While granular activated carbon/R-410A based solar adsorption ice-maker produced the lowest values of ice production per 1 kg of adsorbent and coefficient of performance of 1.38 kg/kgads and 0.104, respectively. Moreover, it can be concluded that the tested pairs are feasible to be used in solar adsorption ice-maker systems, especially in such hot climate of Upper Egypt for food and vaccine preservation and storage.

Hydroxyapatite (HAp) nanorods were synthesized in the presence of licorice root extract (LE) as a green organic template (or biotemplate) at 125 °C through a microwave-hydrothermal synthesis route. The products were characterized for shape, size, crystallinity, and phase purity. For the sample prepared in the presence of LE (denoted as HAp_L, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) revealed a uniform hexagonal phase nanorod product with average dimensions of 105 nm length and 25 nm width. The control sample, prepared in the absence of LE (denoted as HAp_W), showed less crystallinity and poorer morphology. Thermogravimetric analyses (TGA) and differential thermal analyses (DTA) indicated minor moisture contents in both samples. Fourier transform infrared spectroscopy (FT-IR) indicated carbonate-free samples. Raman spectroscopy confirmed the phase purity of the products. Energy-dispersive X-ray spectroscopy (EDX) analysis showed that product HAp_L has a Ca/P atomic ratio close to the theoretical value of HAp. Compared to HAp_W, ζ-potential measurements have shown that suspensions of sample HAp_L were more stable in different aqueous salt solutions. Particle size distribution analysis (PSA) showed a narrow size distribution for sample HAp_L with an average particle size of 105 nm which is advantageous over the apparently multi-disperse sample HAp_W. Nitrogen adsorption/desorption isotherms for both samples showed type III trends, having H3 hysteresis loops in the P/Po range between 0.9 and 1.

Borate glasses with chemical composition 55 B2O3-10 ZnO-x Er2O3–(35-x) Na2O mol.%, (where x = 0, 2 and 4 mol.%) were prepared by conventional melt-quenching. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and UV–Vis spectroscopy were used to characterize the structural and optical properties of the prepared samples. XRD analysis confirms the amorphous nature of these glasses. The density and the molar volume of the prepared glasses were determined. Optical absorption measurements reveal 11 bands corresponding to electronic transitions in Er3+ ion from the ground state 4I15/2 to excited levels. Mass attenuation coefficient (MAC) values were calculated as a function of different photon energies using Phy-X database software. Other shielding parameters such as the half value layer (HVL), the tenth value layer (TVL) and the effective atomic number Zeff were extracted from the determined mass attenuation coefficient (MAC). The results show that MAC increases with the increase in Er2O3 content and decreases with increasing photon energy. The results of this work indicate that the content of Er2O3 is responsible for the attenuation enhancement and that the novel glass prepared in this study holds great promise for future radiation shielding applications.

The strontium-based spinel ferrites were prepared by using the sol–gel technique. Generalized form for fabricated samples was written as: SrErxFe2−xO4, x = 0.00, 0.025, 0.05, 0.075 and 0.10. Various techniques were used to reveal structural, electrical, magnetic and microwave characteristics. Each sample possessed a cubic spinel structure. The impedance was to be enhanced with the involvement of the erbium (Er) ion. Magnetic features were carried out by vibrating the sample magnetometer under the applied field of −2 kOe to +2 kOe. Magnetization values were declined from 70 to 30 emu/g with an increase in erbium contents in the strontium-based spinel ferrites. The cavity Perturbation method was used to obtain microwave measurements. Permeability and permittivity (real and imaginary parts) were reduced with a regular increase of erbium ions. Above-mentioned features of erbium substituted strontium ferrite exhibited their capabilities for microwave absorption applications.

The aim of this work was to carry out systematic studies of how synthesis temperatures affect the morphology and properties of mixed zinc sulfide/zinc oxide (ZnSxOy and ZnO) nanostructures, and to get reliable data on optical constants of ZnSxOy and ZnO nanowires/nanobelts (NW/NB) for the use in device applications. ZnSxOy and ZnO NWs/NBs were fabricated using vapor transport in an open-end tube. Mixed ZnS0.47O0.62NWs was obtained at the synthesis temperature of 850 °C. The sulfur content disappeared as the temperature increased to 950 °C and 1050 °C and the morphology changed to a mixture of NW/NB. The NW prepared at 850 °C were indexed as mixed phases of hexagonal ZnS and hexagonal ZnO structures. The NW/NB prepared at 950 °C and 1050 °C were indexed as pure hexagonal ZnO structures. The thickness, surface roughness, and optical constants of the synthesized nanostructured samples were extracted from measurements of spectroscopic ellipsometry. A two-layers model was proposed to fit the calculated data to the measured ellipsometric spectra. The estimated band gap values of the prepared nanostructures lay 0.66–0.79 eV below the bulk ZnO value due to the lower oxygen content present in the samples and the stresses built in the samples during preparation.

From three different soil textures (clay, silt and sand), 36 soil and soybeans samples were accumulated from the agricultural area of EL-Mynia governorate in Upper Egypt, between (27°36′19.44″N; 30°30′14.14″ E) and (28°48′28.45″ N; 31°00′32.27″ E). Soil textures were prepared by particle size distribution through a pipette method. Its radioactivity measurements were performed with a NaI (Tl) and 3 × 3 inch crystal. The transfer factor (TF) of natural radionuclides from soil to soybeans was calculated. The value of the TF for 226Ra in clay soil ranges from 0.27 ± 0.03 to 0.42 ± 0.05, in sandy soil it ranges from 0.21 ± 0.02 to 0.57 ± 0.07 and in silt soil it ranges from 0.25 ± 0.03 to 0.53 ± 0.06. The TF for 232Th in clay soil ranges from 0.22 ± 0.03 to 0.90 ± 0.12, in sandy soil it ranges from 0.21 ± 0.03 to 1.00 ± 0.13, while in silt soil it ranges from 0.25 ± 0.03 to 0.88 ± 0.12. The TF for 40K in clay soil ranges from 0.95 ± 0.13 to 2.05 ± 0.29, in sandy soil it ranges from 1.21 ± 0.17 to 2.52 ± 0.35 and in silt soil it ranges and from 1.01 ± 0.14 to 1.46 ± 0.26.The results show that the committed effective dose from soybean consumption is between 54.5 and 103.4 μSv y−1 assuming consumption of 20 kg y−1.

Bones are mainly composite materials of equivalent volume fractions of mineral (apatite) and organic (collagen) parts. Their infrared spectroscopic characteristics mirror their composition. Bone di...

Biopolymer-based antibacterial films are attractive materials for wound dressing application because they possess chemical, mechanical, exudate absorption, drug delivery, antibacterial, and biocompatible properties required to support wound healing. Herein, we fabricated and characterized films composed of arabinoxylan (AX) and sodium alginate (SA) loaded with gentamicin sulfate (GS) for application as a wound dressing. The FTIR, XRD, and thermal analyses show that AX, SA, and GS interacted through hydrogen bonding and were thermally stable. The AXSA film displays desirable wound dressing characteristics: transparency, uniform thickness, smooth surface morphology, tensile strength similar to human skin, mild water/exudate uptake capacity, water transmission rate suitable for wound dressing, and excellent cytocompatibility. In Franz diffusion release studies, >80% GS was released from AXSA films in two phases in 24 h following the Fickian diffusion mechanism. In disk diffusion assay, the AXSA films demonstrated excellent antibacterial effect against E.coli, S. aureus, and P. aeruginosa. Overall, the findings suggest that GS-loaded AXSA films hold potential for further development as antibacterial wound dressing material.

We report on structural, magnetic properties of Na-doped La0.8Sr0.15Na0.05MnO3 (LSNMO) nanoparticles (NP) with size about 50 nm elaborated via sol-gel route. The chemical composition was verified using the energy dispersive X-ray analysis (EDAX) and by X-ray photoelectron spectroscopy (XPS). Magnetic characterizations demonstrate that LSMNO exhibits a coexistence of interacting superparamagnetic (ISPM) phase with blocking temperature T-B = 194 K and a ferromagnetic phase with Curie temperature T-C = 255.5 K. At low temperatures, the SPM state undergoes a collective freezing state at T-f = 46 K. the high-temperature regime (well above TC) reveals that NP-LSNMO has a strengthened Griffiths-like phase compared to their bulk counterpart. An itemized investigation of the critical behavior of the material was carried out in the vicinity of T-C. The critical exponents [beta = 0.546(7), gamma = 0.972(6), and delta = 2.94 (5)] were found to be in close agreement with of the mean-field theory. The maximum magnetic entropy change (-Delta(pk)(M)) is about 1.41 Jkg(-1) K-1 and the refrigeration capacity (RC) is 288 Jkg(-1) for a field change of 5 T at T = 215 K. This magnetocaloric response is reasonably high for nanomaterials and, together with its cost-effectiveness, makes NP LSMNO a potential candidate material for active magnetic refrigerators. Besides, the ISPM properties are desirable for hyperthermia applications. Our findings suggest that the magnetic inhomogeneity and the dipolar interaction between the SPM and FM phases in the range T-B < T < T-C are crucial factors in determining the magnetic properties of NP-LSNMO. (C) 2021 Elsevier B.V. All rights reserved. Portuguese Foundation for Science and Technology European Commission QREN-Mais Centro Project Deanship Scientific Research at Jouf University central laboratory at Jouf University

Two dynamic models have been built for air-breathing and conventional polymer electrolyte fuel cells (PEFCs) in order to comparatively investigate the impacts of some key parameters on the transient response to load alterations and the steady-state performance for each fuel cell type. It was found that with load alterations, the dynamic response of the air-breathing PEFC is significantly slower than that of the conventional PEFC and this is due to significantly slower heat transfer coefficients associated with natural convection taking place at the surface of the exposed-to-the ambient cathode GDL. Namely, lower heat transfer coefficient results in poor heat dissipation that eventually leads to: significantly higher and less-responsive-to-load changes cell temperature (compared to those of the conventional PEFC) and subsequently higher ohmic and activation losses. Further, the dynamic and the steady-state performance of the air-breathing PEFC was found to increase with decreasing GDL porosity, decreasing membrane thickness and, to a lesser extent, decreasing overall electrical resistance. These effects are significantly less profound on the performance of the conventional PEFC. All the above findings have been described and discussed in the paper.

A new glass system (50−x)P2O5–20B2O3–5Al2O3–25Na2O–xCoO was manufactured using a standard melt quenching procedure, where 1≤ x ≤ 12 mol%. The characteristics of boro-phosphate-glasses containing CoO have been studied. The effect of CoO on the radiation-protective properties of glasses was established. The density of the prepared glasses as a function of CoO increased. XRD was used to check the vitreous structure of samples. Fourier-transform infrared (FTIR) spectroscopy was used to study the structure of each sample. FTIR demonstrated that connections grew as CoO/P2O5 levels increased, and the FTIR spectra shifted to higher wavenumbers. The increment of CoO converts non-bridging oxygens associated with phosphate structural units into bridging oxygens. This process increases the concentration of BO4 structural units and creates new, strong and stable bonds B–O–P, i.e., there is polymerization of the boro-phosphate glass network. With an increase in the ratio of CoO/P2O5 in the produced samples, ultrasonic velocities and elastic moduli were observed to increase. The coefficients of linear and mass attenuation, the transmittance of photons in relation to the photon energy, the efficiency of radiation protection in relation to the photon energy, and the thickness of the absorber were modeled using these two methods (experimental and theoretical). From the obtained values, it can be concluded that the 12Co sample containing 12 mol% will play the most influential role in radiation protection. An increase in the content of cobalt-I oxide led to a significant increase in the linear and mass attenuation coefficient values, which directly contributes to the development of the radiation-protective properties of glass.

Purpose We introduce a technique that employs a 2D detector in transmission mode (TM) to verify dose maps at a depth of dmax in Solid Water. TM measurements, when taken at a different surface‐to‐detector distance (SDD), allow for the area at dmax (in which the dose map is calculated) to be adjusted. Methods We considered the detector prototype “MP512” (an array of 512 diode‐sensitive volumes, 2 mm spatial resolution). Measurements in transmission mode were taken at SDDs in the range from 0.3 to 24 cm. Dose mode (DM) measurements were made at dmax in Solid Water. We considered radiation fields in the range from 2 × 2 cm2 to 10 × 10 cm2, produced by 6 MV flattened photon beams; we derived a relationship between DM and TM measurements as a function of SDD and field size. The relationship was used to calculate, from TM measurements at 4 and 24 cm SDD, dose maps at dmax in fields of 1 × 1 cm2 and 4 × 4 cm2, and in IMRT fields. Calculations were cross‐checked (gamma analysis) with the treatment planning system and with measurements (MP512, films, ionization chamber). Results In the square fields, calculations agreed with measurements to within ±2.36%. In the IMRT fields, using acceptance criteria of 3%/3 mm, 2%/2 mm, 1%/1 mm, calculations had respective gamma passing rates greater than 96.89%, 90.50%, 62.20% (for a 4 cm SSD); and greater than 97.22%, 93.80%, 59.00% (for a 24 cm SSD). Lower rates (1%/1 mm criterion) can be explained by submillimeter misalignments, dose averaging in calculations, noise artifacts in film dosimetry. Conclusions It is possible to perform TM measurements at the SSD which produces the best fit between the area at dmax in which the dose map is calculated and the size of the monitored target.

To treat the stochastic wind nature, it is required to attain all available power from the wind energy conversion system (WECS). Therefore, several maximum power point tracking (MPPT) techniques are utilized. Among them, hill-climbing search (HCS) techniques are widely implemented owing to their various features. Regarding current HCS techniques, the rotor speed is mainly perturbed using predefined constants or objective functions, which makes the selection of step sizes a multifaceted task. These limitations are directly reflected in the overall dynamic WECS performance such as tracking speed, power fluctuations, and system efficiency. To deal with the challenges of the existing HCS techniques, this paper proposes a new adaptive HCS (AD-HCS) technique with self-adjustable step size using model reference adaptive control (MRAC) based on the PID controller. Firstly, the mechanical power fluctuations are detected, then the MRAC continuously optimizes the PID gains so as to generate an appropriate dynamic step size until harvesting the maximum power point (MPP) under the optimal tracking conditions. Looking specifically at the simulation results, the proposed AD-HCS technique exhibits low oscillations around the MPP and a small settling time. Moreover, WECS efficiency is increased by 5% and 2% compared to the conventional and recent HCS techniques, respectively. Finally, the studied system is confirmed over a 1.5 MW, gird-tied, double-fed induction generator (DFIG) WECS using MATLAB/Simulink.

Recently, borate glasses doped with rare earth ions have attracted increasing attention due to their higher attenuation of ionizing radiations. In this work, Zinc Sodium borate glasses 55 B2O3–10 ZnO–x Y2O3–(35-x) Na2O mol.% (where x = 0, 2 and 4 mol.%) have been prepared using melting quenching procedure. The effect of replacement of Na2O with Y2O3 on the structural and optical properties of the prepared glasses were studied using X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy. The structural analysis performed via XRD indicates that no changes in the amorphous state of the glass samples due to the addition of Y2O3. Increasing the Y2O3 content increases the density of the glass samples. Radiation shielding parameters such as the mass attenuation coefficients MAC, half-value layer (HVL), tenth value layer (TVL), mean free path (MFP), effective atomic number (Zeff), effective electron density (Neff), and equivalent atomic number (Zeq) were estimated at different energy regions using Phy-X database software. The Zeff, Neff, Zeq and Ceff values increase with increasing the Y2O3 content. The increase in Y2O3 content decreases the values of HVL and MFP. The neutron attenuation results show that the neutrons absorption and the fast neutron removal cross-sections increases with increasing the content of Y2O3.

Wound infections are one of the major reasons for the delay in the healing of chronic wounds and can be overcome by developing effective wound dressings capable of absorbing exudate, providing local antibiotic release, and improving patient comfort. Arabinoxylan (AX) is a major hemicellulose present in psyllium seed husk (PSH) and exhibits promising characteristics for developing film dressings. Herein, AX-gelatin (GL) films were prepared by blending AX, gelatin (GL), glycerol, and gentamicin (antibiotic). Initially, the optimal quantities of AX, GL, and glycerol for preparing transparent, bubble-free, smooth, and foldable AX-GL films were found. Physiochemical, thermal, morphological, drug release, and antibacterial characteristics of the AX-GL films were evaluated to investigate their suitability as wound dressings. The findings suggested that the mechanical, water vapor transmission, morphological, and expansion characteristics of the optimized AX-GL films were within the required range for wound dressing. The results of Fourier-transform infrared (FTIR) analyses suggested chemical compatibility among the ingredients of the films. In in vitro drug release and antibacterial activity experiments, gentamicin (GM)-loaded AX-GL films released approximately 89% of the GM in 24 h and exhibited better antibacterial activity than standard GM solution. These results suggest that AX-GL films could serve as a promising dressing to protect against wound infections.

The present framework is primarily concerned with the optical properties of As40Se60-xSnx thin films. The bulk form has been synthesized by the melt quenching technique. The thin films have been prepared by thermal evaporation technique. The XRD and the SEM techniques showed the non-crystalline nature of the prepared glasses. The refractive index n, energy gap, energy loss functions and other optical constants have been determined. The findings refer to increase of the refractive index of thin films with the increase of Sn content. The energy gap decreases to 1.4 eV with the increasing of Sn content for the investigated films. Further explanation of the physical characteristics of the investigated films made following the approach of chemical bond. Additionally, the optical dispersion dn/dλ, phase velocity vp and group velocity Ug have been discussed in detail.

Polyvinyl alcohol (PVA)/carmine dye polymeric composite films are prepared by a solution casting method. Pure PVA, 0.11 wt% carmine dye/PVA, 0.55 wt% carmine dye/PVA, 1.11 wt% carmine dye/PVA, 5.5 wt% carmine dye/PVA, 11.11 wt% carmine dye/PVA and 27.775 wt% carmine dye/PVA have a semi-crystalline structure. The transmission spectrum shows that the light is blocked till 600 nm for 27.775 wt% carmine dye/PVA composite films. The transmittance for the composite 27.775 wt% carmine/PVA is reduced to 61%. The absorption bands and band edges were shifted due to the increase of carmine dye percentage in the PVA matrix. The direct bandgap decreased from 5.16 to 1.65 eV as the carmine dye percentage increased.The indirect band gap decreased from 4.75 to 0.99 eV. The refractive index is strongly dependent on the amount of carmine dye on PVA, and the refractive index increased up to 8. The optical conductivity of PVA/carmine dye composites was divided into different stages according to the photon energy. The highest values of the dielectric loss for PVA/carmine dye composites were found at the lowest frequency (100 Hz). PVA/carmine dye composite films are promising standing up filters for laser power attenuation and optoelectronic devices.

To control outdoor exposure to natural radiation, assessment of activity concentrations of the radionuclides in soils is substantial. In this paper, the activity concentration of natural radionuclides (226Ra, 232Th, 40K) was estimated for 174 agriculture soil samples using a sodium iodide detector (NaI) of (3” × 3”). Soil samples were collected from seven regions (56 locations) in EL-Minya governorate, Upper Egypt. The variability of natural activity concentration with soil’s textures was checked. The texture types of soil samples were silt clay loam, clay loam, sandy clay loam, and sandy silt loam. The obtained results indicate that the mean values of specific activity ranged from 11.3 ± 0.5 (sandy silt loam) to 21 ± 1(silt clay loam), 6.8 ± 0.3 (sandy silt loam) to 13.7 ± 0.7 (sandy clay loam), and 112 ± 5 (sandy silt loam) to 272 ± 13.6 (sandy clay loam) Bq kg−1 for 226Ra, 232Th, and 40 K, respectively. The obtained results were compared with the global average and tolerable limits as recommended in UNSCEAR 2008. On the other side, the radiological hazard resulting from the total natural radioactivity in the studied soil samples was estimated by different approaches. The obtained values were within the recommended safety limit and do not pose significant radiation hazards.

Continuous Yb:YAG laser keyhole welding of the pure copper plate to steel 316L sheet is performed for different laser parameters. The laser-generated welding keyhole and weld melted zone are observed by a high-speed camera. The image is treated by MATLAB and simple code is built to calculate the keyhole and melted zone area. This treatment is validated by the actual welding measurements, and the accuracy of the measurements is tested by the confidence interval law. The images obtained of keyhole and melt zone area in dissimilar laser welding are treated and analyzed to study the effect of changing the laser parameters.

Tellurite glasses own some unique properties that can serve human being developments in several applications. This research work aims to study the optical properties and radiation shielding performance of tellurite glasses containing Li2O and MoO3 described by the formula of xLi2O – (80–2x)TeO2 – (20+x)MoO3, where x = 0, 10, and 20 mol%. The results of the optical studies show that the optical transmission (T) of the studied glass samples increased from 1.21 to 1.42 as the Li2O content increased from 0 to 20 mol%. Such increase was associated with a clear decline in the values of the static dielectric constant of the samples. On the other hand, FLUKA simulation was extensively used to assess and test the radiation shieling performance for each sample involved. The findings of this part reveal that the attenuation factors (e.g. MACs) of LTM glasses varied from 0.038003 cm2/g to 0.16151 cm2/g for LTM-A, from 0.03813 to 0.15611 cm2/g for LTM-B and from 0.03825 cm2/g to 0.14948 cm2/g for LTM-C. Moreover, the transmission factors (e.g. HVLs) of the LTM glasses were minimum at 0.284 MeV with value of 0.814437 cm, 0.90430 cm and 1.03275 cm for LTM-A, LTM-B and LTM-C, respectively. Finally, a large scale comparison was achieved between the studied glass samples and the commercially available ones for several photon energies. This comparison confirmed the utility of using the present glass samples as transparent shielding materials in several applications whether this is in hospitals or any other technological facilities.

In this study the optical parameters and radiation shielding competence of a new glass system is presented. The chemical architecture of the glasses are given as 60Li2O3-10Y2O3-(30-x)B2O3-xDy2O3 (where x = 0.05, 0.5, and 1.5 mol% for LYBD1–3 glass samples). The molar refractivity RMol, molar polarizability αm × 10−24 cm−3, reflectance loss RL, and optical transmission TOpt values were influenced by the chemical description of the glasses. The RMol, αm × 10−24 cm−3, and TOpt all increased as Dy2O3 increased while on the other hand, the reflectance loss declined. The radiation shielding competence of the glasses were investigated through quantities such as the linear attenuation coefficient LAC, mass attenuation coefficient MAC, effective atomic number Zeff, half value layer HVL, and mean free path MFP for photons while the fast neutron removal cross section Σ R was used for fast neutron. The LAC values of the glasses were evaluated through FLUKA simulations and validated through XCOM computation for photon energies 0.284–2.506 MeV. LAC changes from 0.3105 to 0.1016 cm−1 for LYBD1, 0.3239 to 0.1032 cm−1, for LYBD2, and 0.3504 to 0.1040 cm−1 within the energy investigated spectrum. Also, the magnitude of Z eff fluctuates with energy and ranges from 7.53 to 8.38 for LYBD1, while for LYBD2, the variation is from 7.77 to 8.82, and 8.13 to 9.78 for LYBD3. Other evaluated photon shielding parameters showed that the increment of Dy2O3 had a positive influence on the photon shielding capacity of the glasses. The trend of the fast neutron removal cross section Σ R is such that LYBD1 > LYBD2 > LYBD3 with values varying from 0.1064 to 0.1103 cm−1. Comparing the gamma-ray and fast neutron absorbing efficiency of the LYBD glasses with common radiation shields revealed that: the LYBD glasses shield photons and moderate fast neutrons better than some common shields. The LYBD glasses consequently showed good potential for radiation shielding applications. The optical transparency of the glasses also makes them attractive candidates as transparent shields in medical applications of photons.

In this work, the dependence of the spontaneous magnetization on temperature of La0.67Pb0.33MnO3 manganite has been experimentally estimated from the Arrot plots and from the magnetic entropy change. The magnetocaloric effect (MCE) in this sample has been simulated by the Landau theory and the phenomenological model. Theoretical simulations correlated well with the experimental results. A secondorder ferromagnetic-paramagnetic (FM-PM) phase transition has been proved for La0.67Pb0.33MnO3 compound.

The effect of an applied electric field on electronic band structure and optical absorption properties of n-doped InN0.92yP1−1.92yBiy/InP multiple quantum wells (MQWs) was theoretically studied using a self-consistent calculation combined with the 16-band anti-crossing model. The incorporation of N and Bi atoms into an InP host matrix leads to rapid reduction of the band gap energy covering a large infrared range. The optimization of the well parameters, such as the well/barrier widths, N/Bi compositions and doping density, allowed us to obtain InN0.92yP1−1.92yBiy/InP MQWs operating at the wavelength 1.55 μm. Application of the electric field causes a red-shift of the fundamental transition energy T1 accompanied by a significant change in the spatial distribution of confined electron density. The Stark effect on the absorption coefficient of n-doped InN0.92yP1−1.92yBiy/InP MQWs was investigated. The Bi composition of these MQWs was adjusted for each electric field value in order to maintain the wavelength emission at 1.55 μm.

In this paper, a theoretical analysis linked to the molecular field theory and the Bean-Rodbell model has investigated the magnetocaloric effect (MCE) in a La0.67Pb0.33MnO3 sample. We have demonstrated how the mean-field model can adequately simulate the magnetic and magnetocaloric properties of this magnetic system, which may be a candidate material to magnetic refrigerants. The second-order ferromagnetic (FM)-paramagnetic (PM) phase transition has been confirmed. The expressions describing the entropy and its change under the influence of the magnetic field have been derived. A scaling method based on the mean-field theory leads to a direct calculation of the exchange parameter (λ), the saturation magnetization (M0), the total angular momentum (J), and the gyromagnetic factor (g) of our sample. These constants were used to simulate M(H,T) isotherms, which are used again for the determination of the magnetic entropy change (−ΔSM) of La0.67Pb0.33MnO3.

This work covers the surface defects effect of SnO2/MoO3 and SnO2/WO3 structures on photocatalysis. One micrometer thick SnO2 bottom layers with porous microstructure and 0.1 thick micrometers of MoO3 or WO3 top layers were consecutively deposited onto glass substrates using the thermal evaporation technique. First, these bi-layered structures were characterized by X-ray diffraction, Raman spectroscopy and atomic force microscopy in order to identify both their structures and their morphological properties. Second, both UV–vis-NIR spectrophotometer measurements and ellipsometry spectroscopic proved that the band gap decreased from SnO2 to coupled SnO2/MoO3 and SnO2/WO3. In addition, a comparison of the photocatalytic degradation of methylene blue (MB) was done under UV–visible light irradiation. The results showed that these structures exhibit promising candidates to degrade methylene blue (MB). Based on the characterization, it was found that SnO2/MoO3 and SnO2/WO3 structure showed higher photocatalytic activity than that of SnO2. This relatively high photocatalytic activity may be attributed to the charge transfer between those bi-layered oxides. Finally, the antibacterial activity test towards Pseudomonas Aeroginosa showed that only SnO2/WO3 thin film has exhibited antibacterial effect.

An advanced energy conversion catalyst comprising pristine carbon-nanotubes and conductive polyaniline polymer successfully synthesized and characterized for high temperature and non-humidified polymer electrolyte membrane fuel cells. The fabricated polyaniline-based catalyst shown a good distribution of platinum nanoparticles (Pt-NPs), and displayed an electrochemical surface area of 645 cm2/mgPt. The catalyst indicated remarkable catalytic activity towards the oxygen reduction reaction (ORR). The overpotential of ORR, the open-circuit voltage, and the power density of the polyaniline-based catalyst declined by a 30 mV, increased by a 50 mV, and enhanced by 26.5%, respectively, when compared to the polybenzimidazole-based catalyst. The impedance measurements have emphasized the improved catalytic activity and the enhanced fuel cell performance of the polyaniline-based catalyst, showing a remarkable reduction of 45% in the charge transfer resistance. This study revealed the advantages of using polyaniline as an anchor to improve the Pt-catalytic activity, opening the door for the wide applications of hydrogen energy.