Showing papers in "Results in physics in 2019"

Hall and ion slip effects on MHD rotating boundary layer flow of nanofluid past an infinite vertical plate embedded in a porous medium

Abstract: The diffusion-thermo, radiation-absorption and Hall and ion slip effects on MHD free convective rotating flow of nano-fluids (Ag and TiO2) past a semi-infinite permeable moving plate with constant heat source are discussed. Making use of Perturbation technique, we found velocity, temperature and concentration and are discussed through graphs. We evaluated the skin friction, Nusselt number and Sherwood number analytically and computationally discussed. The resultant velocity reduces with increasing rotation parameter and enhances with increasing Hall and ion slip parameters and Dufour parameter. Radiation-absorption parameter leads to increase the thermal boundary layer thickness. Nusselt number decreases with suction parameter and Sherwood number increases chemical reaction parameter.

Design of D-shaped elliptical core photonic crystal fiber for blood plasma cell sensing application

Abstract: In this research, the proposed design presents the compact sensing performances while infiltrating the blood fluid in the central hole of the D-shaped elliptical dual-core photonic crystal fiber (PCF) configuration. The properties such as index difference, coupling length, and transmission spectrum pertains the sensing property of the blood plasma cell. The proposed sensor can detect plasma by finite element method (FEM) which can be utilized to detect the variation of plasmon of light using plasma materials.

Preparation of polypropylene/short glass fiber composite as Fused Deposition Modeling (FDM) filament

Abstract: Mechanical, morphological, rheological, and crystallinity properties of pure polypropylene (PP)/glass fiber (GF) and PP/GF composites containing maleic anhydride polyolefin (POE-g-MA) at three different weight percentages (10, 20 and 30 wt%) were investigated. The test specimens were provided using 3D printing (FDM) and compression molding (CM) methods. Given brittleness and insufficient flexibility of the prepared filaments, POE-g-MA was used at different weight percentages, leading to enhanced filament flexibility. The test specimens were also provided using the CM method to compare the results with those of FDM method. Tensile tests were performed to evaluate mechanical properties of the specimens. Results showed that, addition of GF increased the modulus and strength of the composite while lowering its flexibility; on the other hand the composite exhibited decreased modulus and strength and increased flexibility upon adding the POE-g-MA. The specimens prepared via CM method exhibited higher values of strength and modulus, as compared to those prepared via 3D printing. Results of rheological studies further showed that the introduction of POE-g-MA tends to increase the storage modulus, loss modulus and viscosity, while lowering the value of tan δ. X-ray diffraction (XRD) analysis results indicated higher crystallinity of the specimens prepared via the CM method rather than 3D printing.

Green synthesis, characterization, antibacterial, antioxidant and photocatalytic activity of Parkia speciosa leaves extract mediated silver nanoparticles

Abstract: Green synthesis of silver nanoparticles (PAgNPs) was achieved by bio-reduction of silver nitrate using Parkia speciosa leaf aqueous extract. The PAgNPs formation was confirmed by UV–Vis spectroscopy. The synthesized silver nanoparticles in solution have shown maximum absorption at 410.5 nm, spectrophotometrically. The different parameters like temperature, pH, time, silver nitrate concentration and volume of leaf extract were optimized spectrophotometrically. The SEM, TEM and DLS analysis were used to confirm the average particle size of PAgNPs which were found to be 31 nm, 35 nm, and 155.3 d.nm, respectively. XRD and EDX analysis confirmed the nature and presence of silver. Synthesized PAgNPs showed significant photocatalytic (methylene blue under solar irradiation), antimicrobial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis) and antioxidant (DPPH radical scavenging method) activities. The developed method for the silver nanoparticles synthesis using Parkia speciosa leaf extract is an eco-friendly and convenient method. In near future, the synthesized PAgNPs could be used in the fields of water treatment, biomedicine, biosensor and nanotechnology.

The simplest approach to nonlinear oscillators

Abstract: This paper gives the simplest approach to the cubic-quintic Duffing equation (M.S.H. Chowdhury et al., Results in Physics 7(2017): 3962–3967), providing an extremely fast and relatively accurate estimation of the frequency of a nonlinear conservative oscillator.

Effect of operational parameters on the photocatalytic degradation of Methylene blue dye solution using manganese doped ZnO nanoparticles

Abstract: Photocatalytic degradation of aqueous solution of methylene blue dye under UV light illumination was studied by using manganese doped ZnO ( Z n 1 - x M n x O , where x = 0.00 , x = 0.02 a n d x = 0.05 ) nanoparticles as a photocatalyst. The nanophotocatalysts were synthesized by wet chemical co-precipitation method. The structural, morphological, and optical properties of the photocatalysts were done by X-ray diffraction (XRD), Scanning Electron microscope (SEM), Energy Dispersive X-Ray (EDX), photoluminescence (PL), Fourier Transform Infrared Ray (FTIR) and UV–visible spectroscopic techniques. An improved photocatalytic efficiency of ZnO was observed upon doping with Mn and 2% Mn-doped ZnO exhibited the highest photocatalytic activity among the doped samples. The effect of operating parameters such as amount of catalyst, the initial dye concentration, and initial pH on the rate of dye degradation using 2% Mn-doped ZnO was studied. Under the optimum operation conditions, approximately 99% of dye removal was achieved after 120 min of irradiation.

Improved size, morphology and crystallinity of hematite (α-Fe2O3) nanoparticles synthesized via the precipitation route using ferric sulfate precursor

Abstract: Pure hematite nanoparticles (HNPs) were successfully synthesized via the simple precipitation route by using ferric sulfate precursor and ammonium hydroxide (NH4OH) precipitant. The current study reports the effects of precursor concentrations, from 0.05 to 0.45 M, on the product size, morphology, crystallinity, and lumps formation. X-ray diffraction (XRD) data confirmed the synthesis of pristine HNPs having a rhombohedrally centered hexagonal structure. In addition, the particle size effect on the XRD peak shifting was studied and found to be consistent with the calculated size results by Scherer equation. Transmission electron microscopy revealed mixed polygonal and hexagonal morphologies with an average size of (16–44 nm) depending on the precursor concentration. Scanning electron microscopy depicts lots of agglomerations and lumps with increasing the precursor concentration. Raman spectra not only show the seven phonon modes of pristine hematite phase but also confirm the evolution of the crystal structure with concentration. Thermal analyses proved that the synthesized α-Fe2O3 products in the current work using 0.05 M precursor concentration are well crystallized at around ≈464 °C. Thus, current work presents smaller-sized HNPs crystallized at lower temperature ranges with different morphologies and higher probable vulnerable facets compared to previous studies. This will show improved properties and give rise to higher potentials for various applications. Furthermore, it verifies that the precursor nature is the key factor affecting both size and morphology, whereas, precursor concentration not only affects the particle size as reported previously but also crystallinity, morphology development, and lumps formation of the final product.

Study on the effect of the concentration of Hibiscus sabdariffa extract on the green synthesis of ZnO nanoparticles

Abstract: This work evaluates the effects of different concentrations of Hibiscus sabdariffa flower (Jamaica) extracts on the green synthesis of zinc oxide (ZnO), for the photocatalytic degradation of methylene blue (MB). Zinc nitrate is used for the synthesis of ZnO as a source of the zinc ions. Extracts of 1%, 4% and 8% (% weight-volume) of Hibiscus sabdariffa, in an aqueous medium, were used as reducing and stabilizing agents. In FTIR characterization, the Zn O bond was observed at 618 cm−1. By means of XRD, the material was observed to have a hexagonal crystalline phase (Wurzite). Through XPS, the energy values of 1022 eV for Zn and 531 eV for O were observed, showing the chemical state of Zn+2. The morphology of the ZnO nanoparticles (NPs) varies in its semicircular shape and size distributions depending on the extract used, which range from 30 to 8 nm. The values of the band gap decreased from 2.96 to 2.77 eV as the concentration of extract increased. These materials presented good photocatalytic activity, degrading 97% of MB in 150 min, which are efficient results comparable to ZnO NPs green synthesized via other extracts and other methods.

Temperature effects on characteristics and performance of near-infrared wide bandwidth for different avalanche photodiodes structures

Abstract: In this paper, the influences of thermal and spectral variations on various structures of avalanche photodiodes (APDs) have been deeply investigated. The characteristics and performance of Silicon (Si), Gallium Arsenide (GaAs) and Indium Gallium Arsenide (InGaAs) avalanche photodiodes have been evaluated under effects of different temperature degrees. The impacts of different temperature levels on the band gap energy, detector responsivity, noise equivalent power (NEP), cut-off wavelength, dark current and the photocurrent are studied and analyzed in details. The signal to noise ratio (SNR) and Bit Error Rate (BER) of these APDs are also computed and measured under the influences of different temperature levels and spectral variations. The aim of this paper is to determine the most efficient avalanche photodiode achieving the best performance according to the maximum SNR and minimum BER at high temperature environments. The analysis of the proposed model is performed by MATLAB. It was found that the experimental measured results endorse the analytical computed results. Further, it was observed that the APD (InGaAs) provides performance better than other APD structures in terms of larger SNR and less BER at higher temperature levels. Also, the temperature has a slight effect on the performance of APD (GaAs). So, it is seemed to be stable more than other APD structures and recommended to be used in warm environments and for high temperature applications.

Enhancing the structural, optical and electrical properties of ZnO nanopowders through (Al + Mn) doping

Abstract: Undoped ZnO and Zn0.97−xAl0.03MnxO (x = 0, 1, 2 and 3%) nanopowders (NPs) were synthesized by co-precipitation method. They were characterized by X-ray diffraction (XRD), Fourier transformed infrared (FTIR), Raman, UV–visible, photoluminescence (PL) and impedance spectroscopies. All samples exhibit a single phase wurtzite type. The average crystallite size lying between 22 and 42 nm was found to increase for all doped ZnO samples. The optical transmission in the visible region was improved due to doping. The optical band gap is in the range of 3–3.4 eV and was found to decrease up to 2% of Mn content but slightly increases with further doping. All PL spectra exhibit two emission peaks in UV and visible regions. The deconvolution of the visible emission peak reveals different emissions for all samples. An additional yellow emission is noticed for (Al + Mn) ZnO doped samples suggesting that the incorporation of aluminum and manganese in the zinc oxide host lattice enhances luminescence properties of ZnO. The ac conductivity ( σ ac ) was found to follow Jonscher’s power law and was improved with doping. Cole-Cole plots of all samples were suitably fitted to a circuit consisting in a parallel combination of a resistance and a constant phase element (CPE).

A study of optical wave propagation in the nonautonomous Schrödinger-Hirota equation with power-law nonlinearity

Abstract: This paper investigates the nonautonomous Schrodinger-Hirota equation with power-law nonlinearity via the Unified Method. New nonautonomous optical wave solutions are obtained in polynomial function solutions type. Among these solutions: the optical solitary, optical soliton and optical elliptic wave solutions. The physical explanations and the dynamical behavior of the solutions describing the wave propagation in optical fibers are discussed and analyzed for different choices of the arbitrary functions in the solutions.

Eco-friendly synthesis of Fe3O4 nanoparticles: Evaluation of their catalytic activity in methylene blue degradation by kinetic adsorption models

Abstract: In this work the green synthesis of Fe3O4 nanoparticles by cynara cardunculus leaf extract is presented. This green synthesis route offers a novel and eco-friendly alternative to obtaining of iron oxides nanoparticles. Functional nanoparticles with potential catalytic applications, particularly for water remediation containing organic dyes were synthetized. The structural characterization of the Fe3O4 nanoparticles were carried out by scanning electron microscopy (SEM), X-ray diffraction, techniques. Calculation to obtaining the crystallite size by Williamson –Hall method were performed. Additionally, Raman spectroscopy support the Fe3O4 characterization. Posteriorly, the Fe3O4 nanoparticles were evaluated on the methylene blue degradation. Kinetic adsorption models were employed to establish the behavior during the methylene blue degradation process. Pseudo first order, Pseudo second order, Intraparticle diffusion and Elovich Models were calculated based on the experimental data obtained. Calculations as the correlation factor indicates the best linear fit between the theoretical models and the experimental data obtained during the blue methylene degradation.

The switching of optoelectronics to full optical computing operations based on nonlinear metamaterials

Abstract: The recent progress in optical computing outlines the fact that electronic computing has almost failed to cope with the international optical computation and communication traffic demand. Thanks to the non-linear material (NLM) which pave the way to new designs of new optical devices. A proposal for developing the most basic element in the optical computer such as optical switch, optical gates like OR gate, AND gate, XOR gate, flip-flops…. etc. has been introduced in recent research papers, also a proposal of the optical logic and arithmetic processor (OLAP) and the all-optical a-stable multi-vibrator has been introduced. Here some proposal developments are presented in this track, three components which they are most important in any new optical project those are optical switch, optical oscillator, and optical trap, the optical oscillator was introduced using an electro-optical modulator and, in this study, the oscillator design has no electro-optical elements, also the optical trap here works as an optical memory of binary data.

Effect of Bi2O3 content on mechanical and nuclear radiation shielding properties of Bi2O3-MoO3-B2O3-SiO2-Na2O-Fe2O3 glass system

Abstract: The melt quench method has been used to prepare the xBi2O3-(30-x)MoO3-40B2O3-20SiO2-9Na2O-1Fe2O3 glass system, where x = 15, 17.5, 20, 25 and 30 mol. %. In the energy range of 0.015–15 MeV, the mass attenuation coefficient (μm), half value layer (HVL) and effective atomic number (Zeff) values have been calculated using MCNPX code for prepared glasses. Using the Geometric progression (G–P) fitting method the exposure buildup factor (EBF) and energy absorption buildup factor (EABF) have been computed. In addition, the removal cross-section (ΣR) values for fast neutrons have been evaluated. Moreover, the mass attenuation coefficient for different compositions glasses have been calculated using XMuDat program and XCOM and have been compared with MCNPX values. The μm, HVL and ΣR values of the investigated glass samples have been compared with the different types of concretes in other glass materials. Using the pulse-echo technique, the elastic moduli for glass samples have been measured. The glass sample 30Bi2O3-40B2O3-20SiO2-9Na2O-1Fe2O3 shows the highest values of μm and lowest values of HVL, which indicate that this glass composition is the most effective at radiation shielding.

Charge storage in WO3 polymorphs and their application as supercapacitor electrode material

Abstract: Tungsten oxide is a versatile material with different applications. It has many polymorphs with varying performance in energy storage application. We report simple and facile way to synthesize four phases of tungsten oxide from same precursor materials only by changing the pH and temperature values. Monoclinic, hexagonal, orthorhombic and tetragonal phase obtained, were analyzed and tested for supercapacitor application. The electrochemical analysis of four phases indicates that the hexagonal phase is best-suited electrode material for supercapacitor. The hexagonal phase exhibits higher specific capacitance (377.5 Fg−1 at 2 mV s−1), higher surface capacitive contribution (75%), better stability and rate capability of all four phases.

Analysis of complex viscosity and shear thinning behavior in poly (lactic acid)/poly (ethylene oxide)/carbon nanotubes biosensor based on Carreau–Yasuda model

Abstract: The complex viscosity of poly (lactic acid) (PLA)/poly (ethylene oxide) (PEO) blends and PLA/PEO/carbon nanotubes (CNT) biosensor as a function of frequency is measured and analyzed by Carreau–Yasuda model. This model correlates the complex viscosity to zero complex viscosity, relaxation time, power-law index as well as the shear stress and the width of the transition region between Newtonian and power-law behavior. The impacts of these parameters on the complex viscosity are justified to confirm the Carreau–Yasuda model. The calculations of Carreau–Yasuda model successfully agree with the experimental data at different frequency ranges. The prepared samples show different levels for parameters explaining the shear thinning behavior. A high zero complex viscosity, poor relaxation time, high power-law index, low frequency and a wide transition region between Newtonian and power-law behavior enhance the complex viscosity of samples. Among the studied parameters, the power-law index and the width of the transition region significantly change the complex viscosity. The prepared samples can develop the nano-bio-sensors for detection of various diseases such as cancer.

The effect of using different materials on erbium-doped fiber amplifiers for indoor applications

Abstract: This paper investigated the different materials of optical fibers, two of them are plastic optical fibers that are namely polysulfone (PSU)/vinyl-phenyl acetate (VPAC) with refractive indices of 1.63/1.567, and the second plastic material namely sapphire (S)/polysulfone (PSU) with refractive indices of 1.77/1.63. One of the other materials consists of fluorite (FT)/polytetrafluorophenylmethacrylate (PTFPMA) with refractive indices of 1.433/1.422, where the second material consists of fluoride (FD)/poly methylmethacrylate (PMMA) with refractive indices of 1.56/1.49. Finally, the third material consists of silica (Si)/tetrafluoropropylmethacrylate (TFPMA) with refractive indices of 1.46/1.373. The simulation results are done by using optiwave simulation version 13. FT/PTFPMA fiber channel has outlined 19.23 Tb/s bit-rate with maximum Q-factor of 11.01, a minimum bit error rate of 1.05 × 10−28, gain value of 36.57 dB, and noise figure of 5.67 dB in the presence of vertical-cavity surface-emitting laser (VCSEL). It is observed that VCSEL has superior to continuous wave (CW) laser by the improvement of the performance parameters understudy at the same operating conditions.

Nanoscale adhesion and attachment oscillation under the geometric potential. Part 1: The formation mechanism of nanofiber membrane in the electrospinning

Abstract: An electrospinning process is to produce nanofibers from a polymer solution by a high electrostatic force, which is used to eject jets from a Taylor cone formed on a nozzle. When a moving jet approaches to a receptor within few nanometers during the electrospinning process, a Casimir-like attraction is formed, which attracts the jet’s end to the surface of the receptor. Thousands of thousands nanofibers will be attached on the receptor’s surface or attached on each other, as a result a nanofiber membrane is formed. The geometric potential was implemented to explain the nanoscale adhesion, which is greatly affected by the attachment oscillation. Mathematical models are established to describe the attachment oscillation under the Lennard-Jones potential and the geometric potential, respectively, and their amplitude-frequency relationship is elucidated analytically. The present theory gives an alternative explanation of the gecko effect and molecule scale forces.

High performance dual core D-shape PCF-SPR sensor modeling employing gold coat

Abstract: In this paper, an enhanced performance of dual core D-shape photonic crystal fiber utilizing surface plasmon resonance (DD-PCF-SPR) based sensor is numerically proposed and analyzed. The thickness of gold and pitch parameter are optimized to 30 nm and 1.9 um, respectively, which ensures superior sensor performance. It is revealed; at optimized geometrical parameter, the offered sensor displays a supreme wavelength sensitivity of 8000 nm/RIU, wavelength resolution of 1.25 × 10−5 RIU, a supreme amplitude sensitivity of 700 RIU−1, amplitude resolution 1.7857 × 10−5 RIU and a figure of merit (FoM) of 138 RIU−1 due to the analyte refractive index changing from 1.47 RIU to 1.48 RIU. The identifying features are investigated using modal analysis based finite element method (FEM) incorporating COMSOL commercial software. Finally, a relative review is executed comparing amplitude sensitivity, resolution and wavelength sensitivity of the offered sensor with previously reported sensors. As high sensitivity, simple structure, and tremendous linear polynomial characteristics, the offered sensor will be a talented candidate for the detection of various biochemical and biological samples (DNA, mRNA, proteins, sugar).

Photon and neutron shielding performance of boron phosphate glasses for diagnostic radiology facilities

Abstract: This study focuses on radiation shielding characteristics of Li2O, Al2O3 and ZnO-doped boron phosphate glasses containing PbO and Bi2O3. Mass attenuation coefficient (μ/ρ) values of the glasses have been calculated using MCNPX code at various photon energies ranging from 60 to 120 keV and compared to those of XCOM software. The obtained results exhibited that MCNPX and XCOM are in good agreement at all energies. Some shielding parameters such as effective atomic number (Zeff), effective electron density (Nel), half value layer (HVL), mean free path (MFP) and Photon transmission factors (TF-photon) were determined using the obtained mass attenuation coefficients. Moreover, macroscopic effective removal cross sections (ΣR) and neutron transmission factors (TF-neutron) for fast neutrons have been evaluated. To simulate the attenuation properties of investigated glasses in a diagnostic radiology operation facility (control room), each boron phosphate glass sample was placed in front of a mathematical human head phantom namely SNYDER. For the glasses under examination, average photon flux in the eight detection points, which were located in different points of SNYDER head phantom, was calculated. Among the studied glasses, BPM4 sample has showed superior photon and neutron radiation shielding effectiveness. It can be concluded that boron-doped glasses are superior shielding materials for both gamma ray and neutrons.

Nanoribbon-ring cross perfect metamaterial graphene multi-band absorber in THz range and the sensing application

Abstract: In this paper, we propose a graphene nanoribbon-ring cross structure. A multi-band absorber is obtained by a simple combination of graphene nanoribbons and and graphene ring. We obtain that the theoretical absorption of three resonance wavelengths are 99.8%, 98.4% and 65.7%, respectively. We carefully analyzed each resonance wavelength, and the compact structure makes that small changes in the position of graphene nanoribbons and graphene ring have a great influence on the number of resonance wavelength. Meanwhile, the small changes in the chemical potential of graphene can tune the position of resonance wavelengths in the spectrum. At last, we discuss the sensing properties of this structure. The FoM (figure of merit) values of the three resonance wavelengths are high, and the FoM of the three peaks can reach 4.1, 3.679 and 12.66. The absorbers have great adjustability and great application potential in sensing.

Analytical wave solutions of the (2 + 1)-dimensional first integro-differential Kadomtsev-Petviashivili hierarchy equation by using modified mathematical methods

Abstract: In our research, we ascertain abundant novel exact traveling wave solutions of (2 + 1)-dimensional first integro-differential Kadomtsev-Petviashivili hierarchy equation by two new modified mathematical methods namely called generalized direct algebraic and extended simple equation methods with the help of computer package like Mathematica. These exact solutions are expressed in the forms of trigonometric, hyperbolic and rational function solutions which are established by using our eminent methods and also comparing our results to all of the well-known results that are given in the literature. These methods are more easier and having fruitful applications to solve different nonlinear wave problems in nonlinear science.

Investigation of the effects of Tm3+ on the structural, microstructural, optical, and magnetic properties of Sr hexaferrites

Abstract: SrTmxFe12−xO4 (0.00 ≤ x ≤ 0.10) hexaferrites (HFs) are produced successfully using a sol–gel approach. The structural, optical, and magnetic properties are investigated. The hexagonal phase is confirmed for all the products. The magnetization is measured with respect to the applied magnetic field, M(H). The magnetic parameters including saturation magnetization Ms, remanence Mr, squareness ratio (SQR = Mr/Ms), coercivity Hc, and magnetic moment n B are deduced at room (300 K; RT) and low (10 K) temperatures. It is shown that the ferrimagnetic nature and Tm3+ substitutions lead to decreases in the magnetization and coercivity magnitudes. The results on magnetic properties are investigated extensively with respect to the structural and microstructural properties. The SQR values indicate the formation of a single magnetic domain for the x = 0.0 sample and a multi-magnetic domain structure for the Tm3+-substituted Sr HFs (x ≥ 0.02). The obtained Hc values suggest that the produced HFs are promising candidates for potential magnetic recording applications.

The investigation of gamma-ray and neutron shielding parameters of Na2O-CaO-P2O5-SiO2 bioactive glasses using MCNPX code

Abstract: Bioactive glasses are silicate glasses with sodium, calcium and phosphorus in its composition used to fulfill or support the functions of living tissues in the human body. The superiority of physical and mechanical properties of the bioactive glasses leads to the opportunity to use for radiation protection. From this point of view, radiation absorption parameters of nine bioactive glasses were reported in the present research. The mass attenuation coefficient (μ/ρ) for the selected bioactive glasses was calculated using MCNPX simulation code in the photon energy range 0.02–20 MeV and the results were compared with XCOM data. The values of μ/ρ calculated in two methods were found to support each other. Other vital parameters like half and tenth value layer (HVL and TVL), mean free path (MFP) and effective atomic number (Zeff) for the selected bioactive glasses were also evaluated by utilizing the μ/ρ. ICSW9 glass with more phosphate and sodium contents possess the lowest MFP, HVL and TVL values while has the highest Zeff values among the bioactive glasses under study. To evaluate the neutron protection performance of investigated bioactive glasses, effective removal cross-section values (ΣR) have been determined. The results showed that ICSW9 has also superior neutron attenuation properties. Additionally, exposure buildup factor (EBF) values were found with G-P fitting approach depending on the energy and penetration depths. The bioactive glasses with further equivalent atomic number possesses the minimum value of EBF.

An investigation on shielding properties of BaO, MoO3 and P2O5 based glasses using MCNPX code

Abstract: In the present work, some radiation shielding quantities (mass attenuation coefficients, effective atomic number, effective electron density, half value layer and mean free path) for various BaO–MoO3–P2O5 ternary glass systems have been determined within the 0.015–15 MeV energy range, using WinXCom program. Additionally, the mass attenuation coefficients of all the investigated glasses have been calculated using MCNPX simulation code (version 2.6.0) and compared to those of WinXCom results. Among the studied glasses, BaMoP8 glass sample with MoO3 content of 70% mol is found to have superior gamma-ray shielding characteristics. Moreover, the glasses studied in this paper possess better radiation shielding properties by providing shorter half value layer (HVL) than RS-253 G18 commercial glass and some concrete samples namely ordinary, hematite-serpentine and ilmanite-limonite.

Experimental investigation of photon attenuation behaviors for concretes including natural perlite mineral

Abstract: Perlite mineral contains relatively high water and in general hydrated obsidian forms the perlite which is mainly an amorphous volcanic glass. Photon attenuation properties for different concrete types including natural perlite mineral and B4C have been experimentally investigated by using different radioactive point sources at 81, 276, 303, 356, 384, 662, 1173, 1275 and 1333 keV. SEM and EDAX analyses were carried out to control the crystal structure of the selected concrete types. In this work, HPGe detector based on gamma spectrometer was employed for all experiments. The results revealed that among the prepared concrete samples, the P6 concrete sample has the lowest HVL and MFP values and thus, having best ability to attenuate gamma rays in comparison to the other prepared concretes.

New analytical wave structures for the (3 + 1)-dimensional Kadomtsev-Petviashvili and the generalized Boussinesq models and their applications

Abstract: Different types of soliton wave solutions for the (3 + 1)-dimensional Kadomtsev-Petviashvili and the generalized Boussinesq equations are investigated via the solitary wave ansatz method. These solutions are classified into three categories, namely solitary wave, shock wave, and singular wave solutions. The corresponding integrability criteria, termed as constraint conditions, obviously arise from the study. Moreover, the influences of the free parameters and interaction properties in these solutions are discussed graphically for physical interests and possible applications.

Synthesis, surface properties, crystal structure and dye-sensitized solar cell performance of TiO2 nanotube arrays anodized under different parameters

Abstract: In this paper, TiO2 nanotube arrays were prepared by anodic oxidation method. The effects of water content, anodizing time and sample post-treatment on the morphology and crystal structure of TiO2 nanotube arrays were systematically investigated. We explored the performance of dye-sensitized solar cells (DSSCs) based on dye N-719. The TiO2 nanotube arrays prepared under different water content and different anodizing time conditions were used as photoanodes. The results show that DSSC has best photovoltaic performance when the water content is 2 vol%. With the increase of oxidation time, Jsc increases continuously, open voltage (Voc) and fill factor (FF) increase first and then decrease. The best optoelectronic properties obtained that the short circuit current, open circuit voltage, fill factor and photoelectric conversion efficiency as following, Jsc = 5.2 mA/cm2, Voc = 0.7 V, FF = 0.54, η = 1.96% respectively.

Evaluation of the shielding parameters of alkaline earth based phosphate glasses using MCNPX code

Abstract: Glass systems of composition 16XO–3Al2O3–6CuO–20Na2O–55P2O5 (where X = Sr, Ca, Mg and Ba mol%) have been investigated to check its potential utilize as gamma ray shielding material. Different shielding quantities namely mass attenuation coefficient (µ/ρ), effective atomic number (Zeff), half value layer (HVL) and mean free path (MFP) have been evaluated using MCNPX code and XCOM program at different photon energies between 0.015 and 10 MeV. The obtained data revealed good agreement between the µ/ρ values derived from XCOM and MCNPX code (version 2.6.0). It is found that the mass attenuation coefficients of BaO-doped phosphate glass are higher than those of the other alkaline earth elements–doped glasses, whereas MgO possess the lowest values. This indicates that the BaO-doped phosphate glass is the superior gamma radiation attenuator among the studied glass samples. The gamma shielding performance of the glasses under study has been compared to some commercial glasses and different concrete samples in terms of MFP.

The effect of post annealing temperature on grain size of indium-tin-oxide for optical and electrical properties improvement

Abstract: Background (Problem) Indium tin oxide (ITO) is a transparent conductive oxide (TCO) thin film used as a transparent electrode. Given its high demand for the manufacture of transparent electrodes (high visible light transmittance, low resistance) in applications such as liquid crystal displays, touch screens, light emitting devices and solar cells, ITO thin films have attracted immense research interest. Objectives This study determines the effect of grain size on the optical and electrical properties of the ITO thin films under different annealing temperatures. Materials and methods ITO thin film was deposited at room temperature by a high frequency magnetron sputtering method using a target composed of In2O3 and SnO2. The structural, optical and electrical properties of the thin films annealed at 250 °C, 350 °C, 450 °C and 550 °C for 1 h were then analyzed. Results The research shows the grain size of indium-tin oxide thin films is strongly related to annealing conditions. The grain size was found to increase with increasing annealing temperature, although the crystal structure did not change for all the samples. It was observed that the lowest resistivity (500 × 10−4 Ω-cm) and highest optical transmittances (90–98%) of ITO films were obtained at annealing temperature of 450 °C. At low annealing temperatures, the measured resistivity is dependent on the effect of grain size, where it decreases with increasing grain size. Conclusion This work showed that the grain size of ITO thin films is strongly influenced by post annealing technique and conditions applied, thus providing a tool for enhancing the optical and electrical properties of the film.