Journal of Applied Sciences and Nanotechnology

This work describes the systematic preparation of doped and undoped TiO2 with Er and/or Yb nanoparticles by hydrothermal-assisted sol-gel method with supercritical drying of ethanol, followed by systematic calcination steps at 500°C, 800°C and 1000°C for 2 h. Structural investigation of these powders by XRD shows that our samples are crystalline with a tetragonal structure and an anatase phase well crystallized at 500°C. Annealing at 800°C shows a transformation of the anatase phase into the rutile phase, which is well crystallized at 1000°C. XRD analysis shows that the dopants are incorporated into the TiO2 network without phase separation in these nanoparticles. The study of the grain sizes has shown that they have a nanometric size of about 8-12 nm and that their size decreases with Er and/or Yb doping. The elemental analyzes with micro-EDX using SEM confirmed the presence of chemical elements in the TiO2 nanoparticles with the expected atomic ratios. Examination of the SEM images confirmed the XRD observations. They also prove that the nanoparticles are spherical. Optical analysis with excitation at 488 nm shows the presence of three emission bands in the green and red regions. The heat treatment improves the optical, structural and spectroscopic properties and removes impurities due to the preparation conditions.

In recent years, extensive studies have been devoted to iron oxide nanoparticles (IONPs). Iron oxides are chemical compounds that have various polymorphic forms, including maghemite (γ-Fe2O3), magnetite (Fe3O4), and Hematite (α-Fe2O3). Among them, the most important studied is magnetite (Fe3O4) due to its low cost and low toxicity and its unique magnetic and physicochemical characteristics, which qualify it for use in various biomedical and technological applications. Magnetic particles should be small and have a narrow size distribution for these applications. The smaller the size of the iron oxide particles, the greater their reactivity and biodegradability. In this review, we display summary information on magnetite (Fe3O4) nanoparticles in terms of structure, characteristics, and preparation methods. Because the prepared strategy has been proven to be critical for preferable control of the particle size and shape, in addition to producing monodispersed magnetite (Fe3O4) nanoparticles with a direct effect on their characteristics and applications, special attention will be placed on chemical preparation techniques including Hydrothermal synthesis, Coprecipitation technique, Sol-Gel process, and thermal decomposition method. This review offers specific information for selecting appropriate synthetic methods for obtaining appropriate sizes, shapes, and magnetic properties of magnetite (Fe3O4) nanoparticles (NPs) for target applications.

Recently, bi-based photocatalysts have begun to be used in biological applications. However, the antibacterial ability of a Bi-based photocatalyst is still unclear. In this study, Bi2MoO6 and Bi2WO6 were successfully synthesised by a hydrothermal approach. The fabricated samples were characterised by X-ray diffraction, FESEM, and UV-Vis spectra. Besides, the antibacterial activity of both photocatalyst samples toward E. coli as unfavourable and S. aureus as positive pathogens were studied. Compared with the antibacterial of Bi2WO6, the resultant Bi2MoO6 exhibited high susceptibility to S. aureus bacterial strain, revealing large zones of 24 mm to 29 mm. Bi2WO6 exhibited less susceptibility of 17.5 mm to 21.5 mm compared with the zone of inhibition against tested bacterial E. coli. Besides, a possible mechanism suggested the effect of the nanosheet structure of samples to penetrate the cell membrane, which results in leakage of interior cell and complete death, and these results will provide some support for the applications of Bi2MoO6 and Bi2WO6 in antibacterial materials under typical environments.

The aim of this study was to compare whether the Bispectral Index (BIS) reduces anaesthesia consumption and improves recovery time in coronary artery bypass grafting-off-pump (CABG) surgery without awareness during surgery (ADS). The study was a prospective, randomised and double-blind comparative study of ASA3 patients enrolled for elective CABG surgery under general anaesthesia (GA). Patients received either propofol or isoflurane anaesthesia and their consumption was calculated and compared. Conventional groups CPG-1 and CIG-3 received propofol and isoflurane, and haemodynamic parameters (± 20% of baseline values) were considered for anaesthesia. Groups BPG-2 and BIG-4 received propofol and isoflurane, and the BIS (value 50±5) was used for maintenance of anaesthesia. Haemodynamic parameters, wake-up conditions, duration of intubation, hospital stay and drug consumption were also recorded. For explicit ADS, patients were interviewed 24 hours after extubation. The amount of propofol used was 178 ± 11 ml in CPG-1 and 117 ± 6 ml in BPG-2, with a 34.26% reduction in BIS. The amount of isoflurane used was 39 ± 8 ml in CIG-3 and 25 ± 6 ml in BIG-4, corresponding to a 35.89% reduction in isoflurane requirements. This difference was statistically significant in BIS monitored anaesthesia compared to conventional anaesthesia. The duration of intubation was 2.2 ±1.27 and 2.3 ±1.49 hours in the BPG-2 and BIG-4 groups, respectively (p<0.05). BIS-assisted CABG surgery with adequate depth of anaesthesia (BIS 50 ± 5) prevents ADS, reduces anaesthetic need for anaesthetics and facilitates ultrafast (UFT) extubation.

A stainless steel 316L (SS316L) wires reinforcing heat cure PMMA matrix samples were prepared for dentures applications. Mechanical scratching and electrochemical anodizing for PMMA denture base supported by wires of SS316L were used as straightforward and low-cost outside layer pretreatments. The two pretreatments were used to improve the flexural strength of PMMA denture bases. The mechanical scratching process acts to scratch the surface of stainless-steel wires by mixing the wires with silicon carbide powder inside a rotating Pyrex container. The pretreatment time was varied to be 60, 90, and 120min. The anodizing solution, containing ethylene glycol (EG) with HClO4 acid, was used with a 15V supply and a graphite rod as a cathode in the anodizing process. A variation in the pretreating time to be 15, 20, and 30min for the electrochemical anodizing process was included. A scanning electron microscope was utilized to examine the morphology of surfaces of the SS316L wires, which showed various morphology natures. The mechanical flexural strength test was conducted for all samples statistically to check the results. The flexural strength test results of the composite sample groups of PMMA reinforced with the scratched surface for 90 min stainless steel wire 316L presented the highest flexural strength value (113 MPa) with a 66% increment. All results proved that reinforcing PMMA by ss 316L are enhancing the flexural strength by comparing the results with previous works and pointing to the activity of the used scratching process.

In this work, we reported a study on the hydrothermal process for the preparation of TiO2 NRs films on FTO substrate using two different solutions, the first consisting of (ethanol and titanium butoxide) and the second consisting of (HCl, DIW and titanium butoxide). The study of structural, morphological, optical and electrical properties helped to identify the characteristics of the TiO2 films prepared with the different solvents. The first sample (TO1) exhibited an anatase phase crystal structure with an energy gap of (3.2 eV), while the second (TO2) showed a rutile phase with an energy gap of (3 eV). The (nanorod) morphology was observed in the (TO2) sample, while irregular grains were found in the (TO1) sample. Transmission measurements were performed to analyze the optical properties, which showed that both samples were transparent in the visible wavelength range, with the (TO2) sample with rutile phase exhibiting higher absorption coefficients. The activation energy was (0.0226) eV and (0.0643) eV for the two samples (TO1) and (TO2), respectively. The n-type conductivity was confirmed by Hall effect measurements for both samples. The highest conductivity (300.655) (Ω-1.cm-1) and the highest carrier consternation (1.07355 ×1017) (cm-3) were obtained for sample (TO1).

The study investigated the photoluminescent properties of undoped and rare-earth element erbium-doped solid solutions GaS1-xSex0.1аt% irradiated with gamma-quanta. Erbium doping reduces the photoluminescence intensity in solid solutions. After irradiation D= 300-1000Gy, the photoluminescence intensity increases. An increase in the photoluminescence intensity in irradiated solid solutions is explained by a decrease in the concentration of centres responsible for the fast recombination channel and associated with lattice defects. At T=77K, due to the decay of bound Frenkel pairs, Si and Vs appear in the sulfur sublattice. The Si defects are responsible for the increase in the intensity of the green luminescence band. The redistribution of photoluminescence intensity in the 0.520 - 0.600 µm range is due to energy transfer to rare-earth centres in activated crystals. The investigated results allow us to conclude that doping with erbium leads to a series of emission lines appearing in the visible region of the spectrum.

This research investigates the synthesis of activated carbon (AC) from potato peel waste (PPW). AC was synthesized under atmospheric conditions via two activation methods: chemical activation and carbon dioxide physical activation. The effects of the drying period on precursor preparation and activation methods were investigated. The specific surface area and pore volume of the ACs were estimated using the Brunauer–Emmett–Teller method. The AC from physical activation had a surface area of 1210 m²/g and a pore volume of 0.37 cm³/g, while chemical activation yielded AC with similar surface area but lower pore volume (0.34 cm³/g). The main aim is to produce activated carbon from natural materials and characterize the elemental analysis, surface area, and morphology of ACs from PPW using potassium hydroxide (AC-PPK) and carbon dioxide (AC-PPC) as activating agents. X-ray diffraction showed crystallinity degrees of 35.03% for AC-PPK and 35.46% for AC-PPC. Both methods resulted in AC with low crystallinity, indicating an amorphous structure. Atomic force microscopy (AFM) images of AC revealed surface nanotips with maximum heights of 1,396 nm and 778 nm. Scanning electron microscopy showed the external surfaces full of cavities and highly irregular due to activation. Activated carbon from PPW is a low-cost and effective adsorbent compared to other sources.

This paper introduces an innovative method for measuring laser pulse energy using photoacoustic converters. The concept of paper design and built energy meters using PZT as three specimens have a diameter of (20, 24, and 25) mm, and coating SiO2 was chosen in this test because it has unique properties, is affordable and is compact. Genetic energy meters are expensive. They were comparing the genetic meter (used in this study that is manufactured of pyroelectric material and PZT/SiO2). The outcomes demonstrated that within the laser pulse's energy (100-400mJ). Peak voltage values for PZT composites range from 0.48 to 0.84 volts at the voltage output as their diameter increases (PZT-S with a diameter of 20 mm). The output voltage ranges for PZT-M (diameter 24 mm) and PZT-B (diameter 25 mm) are 0.18 to 0.68 and 0.08 to 0.56, respectively. The design has been built and characterized by measured voltage and energy meter sources. A piezoelectric actuator had been fabricated on silicon sand wafer composites by converting the light waves (the laser pulse) into shock waves. Unlike the energy meter type (pyroelectric) for genetic-, the energy meter created in (PZT/SiO2) is unaffected by Damage caused by high temperatures from laser Nd: YAG pulse energy.