Fabrication and characterization of NiCu/GO and NiCu/rGO nanocomposites for fuel cell application.

This study investigated the electrochemical behavior of NiCu, NiCu/GO, and NiCu/rGO nanocomposites designed by combining a modified Hummers' method and hydrothermal technique. The prepared nanocomposites are tested as electrocatalysts in direct alcohol oxidation fuel cells (DAFCs) to identify the role of GO and rGO as catalyst supports for the enhancement of the NiCu composite performance. The production of the NiCu/GO and NiCu/rGO composites was demonstrated by FTIR spectroscopy, EDX, and SEM analyses. In DAFCs experiments, NiCu/rGO has better catalytic activity than pure NiCu and NiCu/GO composites, whereas the use of rGO and GO as supports enhances the performance of NiCu by 468.2% and 377.7% in methanol and 255.6% and 105.9% in ethanol, respectively. The higher performance was caused by the increased density of active dots and the combined electronic effects in the designed catalysts. The stabilities of the catalysts and charge carriers' dynamics are studied using chronoamperometry and electrochemical impedance spectroscopy.

Sensing of heavy metal Pb2+ ions in water utilizing the photonic structure of highly controlled hexagonal TiON/TiO2 nanotubes.

The detection of heavy metals in water, especially Pb2+ ions, is important due to their severe hazardous effects. To address this issue, a highly controlled hexagonal TiON/TiO2 heterostructure has been synthesized in this study. The fabrication process involved the utilization of atomic layer deposition and direct current sputtering techniques to deposit TiO2 and TiON layers onto a porous Al2O3 membrane used as a template. The resulting heterostructure exhibits a well-ordered hollow tube structure with a diameter of 345 nm and a length of 1.2 µm. The electrochemical sensing of Pb2+ ions in water is carried out using a cyclic voltammetry technique under both light and dark conditions. The concentration range for the Pb2+ ions ranges from 10-5 to 10-1 M. The sensitivity values obtained for the sensor are 1.0 × 10-6 in dark conditions and 1.0 × 10-4 in light conditions. The remarkable enhancement in sensitivity under light illumination can be attributed to the increased activity and electron transfer facilitated by the presence of light. The sensor demonstrates excellent reproducibility, highlighting its reliability and consistency. These findings suggest that the proposed sensor holds great promise for the detection of Pb2+ ions in water, thereby facilitating environmental monitoring, water quality assessment, and safety regulation across various industries. Furthermore, the eco-friendly and straightforward preparation techniques employed in its fabrication provide a significant advantage for practical and scalable implementation.

Angular surface plasmon resonance-based sensor with a silver nanocomposite layer for effective water pollution detection.

For sensing various samples of polluted water and various sodium chloride concentrations using an angular surface plasmon resonance (ASPR), we have introduced a conventional structure and a hybrid heterostructure in the current research. The suggested structures are composed of silver metal, dielectric layers, silver nanocomposite, and a sensing medium. The reflectance spectra of all structures in the visible region were obtained through the utilization of the transfer matrix method by using the angular interrogation method depending on the Kretschmann configuration. Through our findings, five substrate parameters have been optimized to attain the utmost level of sensitivity across all structures: the thickness of Ag-metal, the type and thickness of dielectric materials, the host material type and the volume fraction of nanoparticles for the nanocomposite layer. In this regard, the suggested sensor provides excellent performance with a sensitivity of 448.1°[Formula: see text], signal-to-noise ratio of 0.787, sensor resolution of 0.284°, and figure of merit of 78.766 RIU-1. Therefore, we believe that the introduced design of our ASPR sensor presents a good candidate for an accurate and efficient detection of low concentrations of contaminated water and sodium chloride as well.

Monitoring and simulation of the fuel irradiation behavior in nuclear reactors based on phononic crystal structure.

We have presented in the current work a novel idea for simulating the irradiation behaviors of the nuclear fuel pellets in nuclear reactors by using a one-dimensional defective phononic crystal (1D-DPnC) design was presented. The transmission spectra of the incident mechanical waves were considered basic data for expressing the characteristics of different nuclear fuel-pellets. Herein, the density, sound speed, and Young's modulus of the fuel-pellets represent the key parameters that are influenced by the irradiation behaviors of these pallets. Mixed plutonium-uranium oxide (MOX) nuclear fuel is considered the main fuel in the present study. In addition, a comparison is performed for this fuel with other types of nuclear fuels. Moreover, the mechanical properties of these MOX-pellets are dependent on the porosity, the ratio of oxygen-to-metal (O/M), and the plutonium (Pu-content). The theoretical treatments depend on the transfers matrix method to compute the transmission spectra through the 1D-DPnC. The numerical findings provided that the MOX-pellet has the highest performance compared to other fuel pellets and with sensitivity equal to 59.388 × 103 Hz s/m. It was also reported that the effects of the percentage of the O/M and Pu- content in MOX had a minor effect in a comparison with the impact of porosity. The theoretical simulation agreed extremely with the experimental data reported for these nuclear fuels. Because of the close relationship between sound speed and density, this sensor can be utilized to monitor the porosity, O/M, Pu-content, and density of fuel-pellets as a quick and non-destructive evaluation technique in a nuclear fuel fabrication laboratory. This article has proven theoretically that MOX fuel produced from nuclear waste of uranium dioxide and plutonium dioxide gives excellent results compared to other types of nuclear fuels, and this agrees with experimental researches. Thus, it may contribute in preserving the environment from nuclear waste, and this can be considered a novel kind of purification of environmental pollution treatment.

A doped-polymer based porous silicon photonic crystal sensor for the detection of gamma-ray radiation.

In this research, a theoretical investigation of the one-dimensional defective photonic crystals is considered for the detection of gamma-ray radiation. Each unit cell of the considered one-dimensional photonic crystals (1D PhCs) is composed of two layers designed from porous silicon infiltrated by poly-vinyl alcohol polymer doped with crystal violet (CV) and carbol fuchsine (CF) dyes (doped-polymer) with different porosity. In addition, a single layer of doped-polymer is included in the middle of the designed 1D PhCs to stimulate the localization of a distinct resonant wavelength through the photonic band gap. In particular, the appearance of this resonant mode represents the backbone of our study towards the detection of γ-ray radiation with doses from 0 to 70 Gy. The Bruggeman's effective medium equation, the fitted experimental data to the refractive index of the doped-polymer, and the Transfers Matrix Method (TMM) serve as the mainstay of our theoretical treatment. The numerical findings provide significant contributions to some of the governing parameters such as the thicknesses of the considered materials on the performance of the presented sensor, the effect of incidence angle and the porosity of the considered materials on the resonance wavelength. In this regard, at optimum values of these parameters the sensitivity, quality factor, signal-to-noise ratio, detection limit, sensor resolution, and figure of merit that are obtained are 205.7906 nm RIU-1, 9380.483, 49.315, 2.05 × 10-5 RIU, 3.27 × 10-5, and 2429.31 RIU-1, respectively. Therefore, we believe that the suggested design could be of significant interest in many industrial, medical, and scientific applications.

SPECTROSCOPIC STUDY ON POLY(ACRYLIC ACID-CO-ACRYLAMIDE)-GRAFT-POLYANILINE AS A RADIATION DOSIMETER FOR ALPHA PARTICLES.

Poly(acrylate-co-acrylamide) was a synthesis by chemical oxidation polymerization of an aqueous binary mixture of acrylate/acrylamide (1:1 mole ratio) using ammonium persulphate as an initiator at 70°C under the nitrogen atmosphere. The obtained copolymer was introduced for grafting with polyaniline. The grafting process was performed by chemical oxidation polymerization of aniline using ammonium persulphate as an initiator in hydrochloric acid media at 40°C under the nitrogen atmosphere. Poly(acrylic acid-co-acrylamide)-graft-polyaniline samples irradiated with (alpha-particles) at different irradiation doses (0, 2.33, 8.73, 13.09 and 17.46 Gy) at the same linear energy transfer. The change in the morphology, optical properties and the energy gap of poly(acrylic acid-co-acrylamide)-graft-polyaniline samples were studied.

Assessment of natural radioactivity and radon exhalation rate in Sannur cave, eastern desert of Egypt.

Activity concentrations of 238U, 232Th and 40K in rocks and soil samples collected from Sannur cave, Beni Suef governorate, eastern desert of Egypt, were determined using the high-resolution gamma spectrometry technique. The results show that the concentrations of the naturally occurring radionuclides are the following: 238U ranged from 8.51 +/- 1.23 to 20.66 +/- 2.12 Bq kg(-1), 232Th ranged from 7.69 +/- 1.02 to 22.73 +/- 1.60 Bq kg(-1) and 40K ranged from 185.74 +/- 0.42 to 2084.70 +/- 23.30 Bq kg(-1). The radium equivalent activity (Raeq), the absorbed dose rate (D), and the external hazard index (Hex) were also calculated and compared to the international recommended values. The radon concentration and radon exhalation rate from the rock and soil samples were measured using the Can technique. The average value of annual effective dose for cave workers is 1.98 mSv y(-1), while for visitors it is 2.4 microSv per visit. The radon exhalation rate varies from 0.21 +/- 0.03 to 1.28 +/- 0.02 Bq m(-2) h(-1). A positive correlation has been observed between uranium content and radon exhalation rate.

Radon level and radon effective dose rate determination using SSNTDs in Sannur cave, Eastern desert of Egypt.

For the assessment of inhalation doses due to radon and its progeny to cavern workers and visitors, it is necessary to have information on the time integrated gas concentrations and equilibrium factors. Passive single cup dosimeters using solid state nuclear track detectors (SSNTD) is the best suited for this purpose in wadi Sannur cave, Beni Suef, Egypt. The average radon concentration measurements for the cave are 836 +/- 150 Bq m(-3) by CR-39 detectors and for equilibrium factor an overall average of all measured values was used 0.687. The effective dose for cave workers is 3.65 mSv/year while for visitors is 23 muSv/year. Comparing these values to the Ionizing Radiation Regulations (IRR) values which indicate that the estimated effective doses for workers and visitors in this cave are less than the average overall radon dose.