Filed Emission Scanning Electron Microscopy Research Articles

Fabrication and performance evaluation of rGO-PANI supported NiP/TMD based biosensors for electrochemical detection of dopamine

In this study, we present a novel approach for electrochemical sensing of DPA through the development of a unique electrode. It (WM-GP@NiMoP) composed of a mixed transition metal dichalcogenides (WS2-MoS2) supported by rGO and PANI, embedded via a facile electroless NiMoP plating technique. To evaluate the physico-chemical properties of the coatings, including phase analysis (X-Ray diffraction studies), morphology (Filed emission scanning electron microscopy), topology (Atomic force microscopy) and to assess the catalytic activity of the electrode for DPA sensing. The sensing behavior under various operating conditions, encompassing scan rate and pH of the analyte. The durability and performance evaluation were conducted to identify the consistent performance at an optimal pH value of 7 and it shown remarkable selective sensitivity and suppression of glucose and ascorbic acid interferences. The k0 values for the reversible electrode systems like dopamine was reasonable (5.3 ×10−10 cm/s) for the respective oxidation reactions. The CV analysis envisages the sensing potential of electrode towards DPA oxidation due to synergistic effect between PANI and rGO to MTMD on NiMoP coated electrodes. The work highlights the remarkable sensing capabilities of the WM-GP12 @NiMoP electrode in the field of electrochemical detection of DPA. Its exceptional sensitivity towards sensing of DPA establishes it as a significant advancement in electrochemical sensing technology.

Investigation of structural properties and antibacterial activity of AgO nanoparticle extract from Solanum nigrum/Mentha leaf extracts by green synthesis method

Abstract Solanum nigrum and Mentha leaf extracts were used as reducing and stabilizing reagents in the green synthesis of silver oxide nanoparticles (AgO NPs), and their antibacterial efficacy was subsequently evaluated. The structure and morphology of AgO NPs were evaluated using X-ray diffraction and filed emission scanning electron microscope. High-resolution transmission electron microscopy images were used to analyze the characteristics of certain particles with clearly discernible atomic structures. The functional group and elemental composition of AgO NPs were investigated using fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy. Ultraviolet–visible spectroscopy was used to determine the energy band gap (E g) of the sample. The dielectric constant of both samples was found to be inversely proportional to frequency, whereas the dielectric loss was found to be directly proportional to temperature but directly proportional to frequency. This suggests that the space charge has an effect on the mechanism of charge transfer as well as polarizability. AC conductivity rises and is inversely proportional to temperature increases. AgO NPs had a size range of around 56 nm and were mostly spherical. The antibacterial potential of the synthesized AgO NPs using both extracts was compared by the well-diffusion method. AgO NPs at 50–100 µg·mL−1 concentration significantly inhibited the bacterial growth of Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumonia.

Enhancing Photocatalytic Activity of Bismuth Ferrite (BiFeO3) via Gadolinium and Copper Doping: A Sol-Gel Synthesis and Characterization Study

In this current research work, the sol-gel method was employed to synthesise, characterize and evaluate the photocatalytic activity of bismuth ferrite (BiFeO3, BFO) doped with two distinctive components consisting of a rare earth element Gadolinium (Gd) and a transition metal Copper (Cu). The dopant concentrations were systematically varied with different weight percentages (wt.%) denoted as Bi1-xGdxFe1-yCuyO3 (where ‘x’ = 0.10, 0.15 and 0.20 wt.%, where ‘y’ = 0.05, 0.10, and 0.15 wt.%). Subsequently, characterizations of the prepared samples were conducted using an array of cutting-edge analytical techniques including X-ray diffraction (XRD), filed emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX), and transmission electron microscopy (TEM). The XRD analysis results indicated that the presence of small impurity peaks was found in both Gd-doped BFO and GdCu-doped BFO. The FE-SEM and TEM results provided confirmation that the material was observed as a spherical shape, and the elemental compositions were also confirmed through EDAX analysis. The photocatalytic degradation of Rhodamine B dye under the influence of visible light irradiation was carried out and the results revealed varying degradation times, specifically, for Gd and Cu-doped BFO (Gd and Cu = 0.1 wt.%) achieved almost 98% degradation occurred in 30 minutes.

Self-healing metal matrix composite of nitinol wire-reinforced A356 alloy matrix by stir casting technology

The current demand for novel and self-healing material in today’s industries is one of the key challenges. Many engineering applications required tailored properties including self-healing characteristics in novel engineering materials. In this regard, an attempt is made to develop the metal matrix composite of aluminum A356 alloy by utilizing the properties of Nitinol alloy (wire) through a semi-solid metal processing technique. The investigation was validated by light-microscope images of the developed material. Further, filed emission scanning electron microscopy images are taken from the specimens for morphological examination. The elemental confirmation of the produced material is conducted through Energy Dispersive X-Ray Analysis (EDX) spectrum. The results revealed the random dispersion of reinforcement in the matrix phase and EDX confirms that the major constituents of A356 alloy and the Nitinol wires. At last, the crack analysis is conducted before and after hearing which reveals that the interlocks of Nitinol wire with the alpha Al phase of base alloy can provide the ability to close the crack and it can recover the deformed surface by 17.35%.

Synthesis of Manganese Dioxide Nanoparticles by Plant Extract Mediated and their Effect on Biofilm Formation

In the current work, Punica granatum L. peel, Artemisia herba-alba Asso., Matricaria chamomilla L., and Camellia sinensis extracts were used to prepare manganese dioxide (MnO2) nanoparticles utilizing a green method. Energy-dispersive X-ray (EDX) analysis, Fourier Transform Infrared Spectroscopy (FTIR) analysis, and Filed emission-scanning electron microscopy (FE-SEM) analysis were used to evaluate the produced MnO2 NPs. FE-SEM pictures demonstrated how agglomerated nanoparticles formed. According to FE-SEM calculations, the particle size ranged from 18.7-91.5 nm. FTIR spectra show that pure Mn-O is formed, while EDX results show that Mn and O are present. The ability to suppress biofilm growth in the produced MnO2 NPs was examined. The outcomes showed that both bacterial and fungal biofilms were effectively inhibited by the MnO2 NPs produced.

Designing hybrid nanocubes-like cobalt stannate with appliance of MWCNT's nano composite for electrochemical detection of dopamine in bio-clinical samples

In this work, Co2SnO4 having nanocubes like structure synthesized via simple co-precipitation method and the nano-composite was prepared with appliance of multi-walled carbon nanotubes (MWCNT's) and employed for the determination of neuro-transmittance of dopamine (DA) in biological sample. The Co2SnO4 nanocubes and Co2SnO4@MWCNTs are characterized through distinct spectroscopic and microscopic methods, such as Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction spectroscopy (XRD), Raman spectroscopy, Filed emission scanning electron microscopy (FE-SEM), and electron spectroscopy for chemical analysis (ESCA) and as well as electrocatalytic activity was examined by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and amperometry techniques. Under optimal circumstances, the nano composite exhibited better activity over bare GCE. Moreover, Glassy carbon electrode (GCE) modified with Co2SnO4@MWCNTs was high sensitive and selective towards the determination of DA in presence of common interfering biomolecules. The electro analytical parameters via wide linear range (50–350 nM), low detection limit of 10.3 nM, sensitivity 0.043 nM mAcm−2 obtained by DPV analysis. The reliability of the Co2SnO4@MWCNTs/GCE electrode confirmed by real sample analysis of human urine sample and dopamine hydrochloride injection shows favor recovery percentage.

Influence of non-magnetic ions doping on structural, morphological, optical, and magnetic properties of nanocrystalline zinc oxide powders

In this research study, nanocrystalline non-magnetic ion-doped zinc oxide powders are synthesized through sol-gel auto combustion with a variety of different ions (Mg, Al, and Ca) at a range of concentrations (0, 5%, 10%, 20% mol). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), filed-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometer (XPS), UV–visible diffuse reflectance spectroscopy (UV-DRS), photoluminescence spectroscopy (PL), and vibrating sample magnetometry (VSM) were then used to investigate the calcined products, whereupon the structures, chemical bonds, surface texture, chemical composition, morphologies, particle size, surface elemental composition, electronic state, optical and fluorescence properties including magnetism were reported for each of the samples. From XRD it could be determined that the introduction of minuscule quantities of magnesium and calcium ions to the zinc oxide powder produced solutions of hexagonal solid MgZnO and CaZnO, while composites of Mg/ZnO, CaO/ZnO, Al2O3/ZnO could also be observed, without impurity phases. Textural properties of these modified samples observed from SEM, FE-SEM, and TEM were superior to that of the pure ZnO. XPS studies confirmed the substitution of Zn2+ by Mg2+ and Ca2+ for the samples of low doping concentration. UV-DRS analysis showed that samples which had been optimally modified exhibited improved levels of absorption when compared to visible spectral observations of the pure sample. In comparison to the pure sample, the modified samples also showed higher bandgap energy (Eg). In the pure sample, violet and blue emission bands were seen in the PL spectra ranging from 350 to 430 nm, but these emissions showed significant changes in intensity as the concentration of non-magnetic ions was increased. Furthermore, VSM results revealed that diamagnetism of zinc oxide can be adjusted through the introduction of non-magnetic ions to paramagnetism and ferromagnetism.

Alginate/dye composite film-based colorimetric sensor for ammonia sensing: Chicken spoilage

In this study, Alginate (Alg)/Ca2+/dye composite films were fabricated using the solution casting method. The dyes used to include methyl red, phenol red, thymol blue, bromothymol blue, m-cresol purple, and bromocresol purple in the overall pH range of 4.4–9.6. The chemical composition and morphology of the Alg/Ca2+/dye composite films structure were investigated by Fourier transform infrared spectroscopy (FT-IR), filed emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The Alg/Ca2+/dye composite films were semi-transparent and mechanically flexible. The studied parameters include color volume, response time, recovery, reusability and drawing of the calibration curve along with statistical features including X¯, S, RSD, LOD, and LOQ. Colorimetric indicators used in the presence of pollutants (ammonia as the main pollutant released during spoilage of protein products) produce visible color changes to the naked eye. The observed changes are easily understood by consumers and non-experts.

Effect The Finalizations Multi Wall Carbon Nanotube on The Characteristics of Polypyrrole Thin Films

The nanocomposite (PPy/fMWCNT) is prepared via electrochemical polymerization onto indium tin oxide (ITO) coated glass for pyrrole (Py) monomer with oxalic acid (C2H2O4) and various concentration from functionalized multi wall carbon nanotube fMWCNT (0.01, 0.02) in the 130 mL from distilled water. The structure, morphology and optical properties of thin films were investigated via X-Ray diffraction (XRD), Filed Emission Scanning Electron microscopy (FE-SEM), ultraviolet-visible (UV-VIS) spectroscopy and Fourier Transform Infrared (FT-IR) Spectroscopy. The X-ray diffraction pattern indicates that the prepared thin films are of polycrystalline structure at 2θ= (25, 42)o. The band gap of thin films decreases from 2.4 to 2.09 eV as the fMWCNT increased from 0.01 to 0.02 M, whereas FTIR showing the distinctive bonds of these films

Optimal Enhancement of Power Conversion Efficiency of Monolithic Perovskite Solar Cells by Effect of Methylammonium (MAI)

In the present work, the performance of monolithic perovskite solar cells (mPSCs) was evaluated with regard to the concentration of methylammonium iodide (MAI) perovskites. The five different perovskite layers were carried out using different ratios of MAI:PbI2, labelled as A0, A1, A2, A3, and A4 accordingly, with corresponding ratios of 1:1, 1.1:1, 1.2:1, 1.3:1, and 1.4:1. In this study mPSCs with a sandwich type structure of glass/FTO/compact (c)-TiO2/mesoporous (mp)-TiO2/mesoporous (mp)-ZrO2/carbon was fabricated for this purpose. The fabricated mPSCs films were fully characterized by X-ray diffraction, Raman spectra and Filed emission scanning electron microscopy (FE-SEM). The photovoltaic characteristics were measured under AM 1.5, It was found that power conversion efficiency (PCE) increased with the increasing the concentration of MAI:PbI2 perovskites, from 1:1 to 1.1:1M. The maximum PCE of 17.68% was achieved mPSCs with MAI:PbI2 (1.1:1) as compared to mPSCs with MAI:PbI2 (1:1) PCE of 15.2%.

Pulsed laser-assisted synthesis of nano nickel(ii) oxide-anchored graphitic carbon nitride: Characterizations and their potential antibacterial/anti-biofilm applications

Abstract Nickel(ii) oxide-graphitic carbon nitride (n-NiO@g-C3N4) nanocomposite, in which nickel oxide nanoparticles (n-NiO) are anchored on the polymeric surface of graphitic carbon nitride (g-C3N4), was synthesized using the pulsed laser post processing (PLPP) in liquid medium. In the PLPP method, the precursors (NiO and g-C3N4) were simultaneously subjected to pulsed laser-induced fragmentation, and pulsed laser-induced defect engineering (anchoring of NiO on g-C3N4). To optimize the functionality of the material, n-NiO@g-C3N4 with four different mass contents of n-NiO was synthesized. The synthesized n-NiO@g-C3N4 nanocomposite and its composite partners (n-NiO and g-C3N4) were structurally, morphologically, elementally characterized by X-ray diffraction, filed emission scanning electron microscope, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analyses. As a first anti-microbial application, n-NiO@g-C3N4 was used to evaluate the minimal inhibitory concentration and minimal bactericidal concentration against the gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa bacteria. As a second anti-microbial application, the efficacy of n-NiO@g-C3N4 nanocomposite to retard S. aureus and P. aeruginosa biofilms’ growth was evaluated. It was found that for both applications, n-NiO@g-C3N4 nanocomposite exhibited an excellent anti-bacterial activity compared to pure g-C3N4.

Excellent Antimicrobial, Antioxidant, and Catalytic Activities of Medicinal Plant Aqueous Leaf Extract Derived Silver Nanoparticles

Antimicrobial resistance is one of the crucial public health challenges that we need to combat. Thus, in concern over public health and the economy, controlling the emergence of infectious diseases is critical worldwide. One of the ways to overcome the influences of antimicrobial resistance is by developing new, efficient, and improved antimicrobial agents. Medicinal plant-derived silver nanoparticles (AgNPs) are under intensive examination for a variety of therapeutic purposes and targeted applications in nanomedicine and nanotechnology. Plants belonging to the genus Thevetia [Syn. Casabela], which is known for its medicinal uses and has rarely been applied for the synthesis of AgNPs, is an attractive alternative as they have a high content of secondary metabolites. Herein, using aqueous leaf extract of Cascabela thevetia, which was locally found in the Makkah region, Saudi Arabia, green synthesis of AgNPs is reported. Active components of Cascabela thevetia aqueous leaf extract were sufficient to reduce AgNO3 into AgNPs and stabilize them as this was confirmed through UV-Visible absorption, Fourier transforms infrared (FTIR), X-ray diffraction (XRD), filed emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) studies. UV-Visible, HPLC, and FTIR analysis demonstrated the presence of gallic acid in aqueous extract and solution of C-AgNPs. The spherical Cascabela thevetia derived C-AgNPs with an average diameter in the range of 20–30 nm were highly dispersed, as seen from FESEM and TEM images, and demonstrated the high antibacterial and antifungal activities when incubated with Gram-positive bacteria Methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis), Gram-negative bacteria Escherichia coli (E. coli), Salmonella typhimurium (S. typhimurium), Klebsiella pneumoniae (K. pneumoniae), Pseudomonas aeruginosa (P. aeruginosa) and fungi Candida albicans (C. albicans) and Candida parapsilosis (C. parapsilosis). The lowest MIC values of C-AgNPs versus S. aureus, E. faecalis, and E. coli were found. Finally, the antioxidant activity and catalytic property of C-AgNPs were assessed by neutralizing DPPH free radical and reducing methylene blue and rhodamine B dyes, respectively.

Microstructure anomaly during welding and its influence on the mechanical properties of dissimilar weldments of P92 martensitic steel and AISI 304L austenitic stainless steel

In this investigation, microstructural characteristics, mechanical properties, and residual stress magnitude of dissimilar weld joints (DWJs) between creep strength enhanced ferritic-martensitic (CSEF) P92 steel and austenitic stainless steel (ASS) 304L has been investigated. The Thermanit MTS 616 (P92 filler) filler metal was employed to prepare P92/304L SS DWJs. The groove geometry also plays a crucial role in DWJs, so the conventional V-groove and narrow shape groove geometry was adopted for P92/304L SS DWJs. The microstructure characterization was performed using optical microscope (OM), scanning electron microscope (SEM), and filed emission SEM (FESEM). The microstructural examination showed the formation of the δ-ferrite grains and unmixed zone (UZ) at the weld interface. The martensitic microstructure produced after welding is brittle due to quenched martensite and the dissolution of precipitates. Thus, the post-weld heat treatment (PWHT) known as tempering was carried out at 760 °C for the period of 2 h to get tempered martensitic microstructure. The ultimate tensile strength (UTS) of the as-weld (AW) and PWHT tensile specimen of the P92/304L SS DWJs was 660 MPa and 643 MPa, respectively for V-groove geometry specimens and 640 MPa and 609 MPa, respectively for narrow groove geometry specimens. The tensile fracture was experienced at 304L base metal, and the UTS value of DWJs was very close to the UTS of the 304L SS. The average microhardness value of the martensitic weld metal (352HV0.5) and coarse-grain heat-affected zone (CGHAZ, 366HV0.5), fine grain HAZ (FGHAZ, 320HV0.5) in the AW state was beyond the maximum permissible hardness value of 265HV0.5, as per the A335/A335M − 15a standard. The hardness value beyond 265HV0.5 indicates the undesirable brittle martensitic microstructure. After PWHT, the micro-hardness value of the CGHAZ (235HV0.5), FGHAZ (215HV0.5), and inter-critical HAZ (ICHAZ, 201HV0.5) was below the maximum allowable value of 265HV0.5 for P92 material because of the tempering of the quenched martensite. However, the Charpy test result concluded that the problem associated with the martensitic P92 filler is to obtain an acceptable value of the impact toughness of weld metal in AW state. The Charpy impact toughness of weld metal for P92/304L SS DWJs in AW condition was 10 J (V-groove geometry) and 37 J (narrow groove geometry), while for PWHT condition, it was 188 J (V-groove geometry) and 150 J (narrow groove geometry). The impact toughness of the P92 filler weld was below the minimum requirement of 47 J (EN ISO 3580:2017) in AW state. However, the impact toughness of the welds made by using P92 filler metal met the minimum requirement of 47 J (EN ISO 3580:2017) after PWHT due to the tempering of the martensite. The residual stress analysis using deep hole drilling (DHD) technique revealed the existence of the compressive residual stresses in the weld metal and P92 HAZ in as-weld and PWHT condition. The compressive stress was dominant because of the martensitic phase transformation.

Frictional Behavior and Mechanical Performance of Al Reinforced with SiC via Novel Flake Powder Metallurgy

This paper targets developing new low-cost sustainable materials. To achieve this objective, aluminum was utilized as base material for metal matrix nanocomposites (MMNC). Three routes of advanced manufacturing techniques were designed and implemented. Flake powder metallurgy as a reliable method to synthesis nanocomposites powder was employed. By reinforcing aluminium with SiC and using a similar amount of both constitutes, three metal matrix nanocomposites (MMNCs) with different properties were produced. The ball milled powder were characterized using filed emission scanning electron microscope (FE-SEM) to analyze the morphology of the powder. Different investigations and analysis were conducted on the produced samples. These include X-ray diffraction (XRD) analysis, density and porosity, mechanical properties, and frictional performance. The obtained results include relative density, Young’s modulus, compressive yield strength, elongation, toughness, hardness, coefficient of friction, and specific wear rate. Achieving superior mechanical and tribological performance is evident from these results. This is accredited to the homogeneity of the reinforcement dispersion within the aluminum matrix.

Synthesis And Studied Structural and Morphological Properties of 1-Dimensional Zno-Ag2O-Ag Nanowire

1-dimensional zinc oxide (ZnO) - silver oxide (Ag2O) – silver (Ag) nanowire was prepared using a simple and inexpensive bottom-up chemical method. X-ray diffraction (XRD) results showed the presence of diffraction peaks of ZnO and Ag2O with hexagonal wurtzite phase of ZnO. Energy Dispersive X-ray (EDX) results showed the presence of energy peaks of Zinc (Zn), Silver (Ag), and Oxygen (O) elements. Filed Emission Scanning Electron Microscopy (FE-SEM) results showed that the surface morphology is nanowire (1-dimensional structure) with shapes similar to hedgehog spines and have small nanoscale diameters. The present work represents a promising step in the preparation of a 1-dimensional nanowire.

Reinforcement of denture base materials with Nano sisal fibers powder

The aim of research to evaluate the mechanical properties of PMMA reinforced with natural powder. Materials and Methods: In total, 90 specimens were prepared. Specimens were divided into 3 groups depended on the concentration of Nano powder, first group (30) specimens of PMMA (control group), second and third groups of 60 specimens of PMMA with Nano sisal fibers powder with two different concentration (0.5 and 1)% wt. Three point bending test was performed to measure the flexural strength of all specimens. Surface hardness was assessed with durometer hardness tester (shore D). The profilometer device was used for surface roughness test. Filed emission scanning electron microscope (FESEM) was used to observe the fracture surface of specimen. ANOVA test was used for statistical analysis. Results: the results of this study refer to a highly significant differences in the flexural strength of PMMA reinforced with Nano sisal fibers powder compared with control specimens and significant differences in surface roughness. Non- significant differences was detected in surface hardness among the reinforced group and control group. The reinforcement of PMMA with Nano sisal fibers powder significantly increased its flexural strength and surface roughness with non- significant in surface hardness.

Two- stage synthesis of SnO2-Ag/MgFe2O4 nanocomposite for photocatalytic application

In this research, photocatalytic nanocomposite of MgFe2O4/SnO2 was synthesized using two-stage precipitation method. Furthermore, the effect of adding Ag in different percentages was also investigated. The synthesized composite powders were characterized by X-ray diffraction (XRD), filed emission scanning electron microscopy (FESEM), UV-visible spectroscopy and BET analysis. The results of XRD showed that with increasing the percentage of MgFe2O4, the size of SnO₂ crystals decreases. The FESEM micrographs showed that with increasing the percentage of MgFe2O4, the particle size distribution became more uniform and the agglomeration of the particles decreased. Examination of the UV-visible absorption spectrum of the composite powders proved that the addition of MgFe2O4 ferrite to SnO₂ increased the absorption rate and also the addition of Ag had little effect on the adsorption rate of the composite. Investigation of photocatalytic activity of synthesized powders and their comparison showed that by compositing SnO₂ and MgFe2O4, the degradation reaction efficiency can be increased. Adding Ag can also increase the degradation mechanism by preventing electron- holes recombination.

Influence of La-Nb co-substituted Sr ferrite on microstructure, spectrum and magnetic properties of hexaferrites

The M-type Sr hexaferrites with nominal compositions Sr1−xLaxNbxFe12−xO19(x = 0.00, 0.04, 0.08, 0.12, 0.16, 0.20) were fabricated by solid-state reaction method. The microstructure and magnetic properties of hexaferrites were characterized by X-ray diffraction (XRD), Fourier transformer infrared (FTIR) spectroscopy, filed emission scanning electron microscopy (FE-SEM) and vibrating sample magnetometer (VSM). The regular changes of microstructure and magnetic properties were studied at 1300 °C by doping quantity. XRD results show that the substitution of La-Nb is successful when x < 0.16, and α-Fe2O3 begins to appear when x > 0.16; FT-IR shows that there are frequency bands of tetrahedral and octahedral Fe‒O at 613 cm−1 and 451 cm−1, which proves the formation of lattice and structure of M-type Sr1−xLaxNbxFe12−xO19 hexagonal ferrite respectively; The SEM micrographs are regular hexagonal block with tight arrangement and obvious layering. EDS indicates that all elements are predetermined and no other elements are produced. VSM shows that the sample obtains high saturation magnetization (Ms), and increases slightly with the increase of doping amount. The coercivity (Hc) first increases with Nd-Nb Zn content (x) from 0.00 to 0.04, and then decreases when Nd-Nb Zn content x > 0.08; the value of SQR, magnetic crystal anisotropy constant (k1) and magnetic anisotropy field (Ha) decrease with the increase of doping amount, and the number of magnetons (nB) is consistent with the saturation magnetization (Ms). In this paper, for the first time we have studied the mechanism of La-Nb co-substituted which will lead to the change of ferrite morphology and properties at high temperature.

Studies of crystallization kinetics and optical properties of ZnO films prepared by sol–gel technique

The crystallization of ZnO prepared by sol–gel technique was investigated under nonisothermal conditions by differential scanning calorimetry (DSC) and prediction isothermal method. The transformation from the amorphous to crystalline state was investigated by X-ray diffraction (XRD). The influence of the annealing temperature on the structure of the ZnO was studied by Filed Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM). Two exothermic changes were reported between the temperature ranges 590–710 K and 645–750 K for first and second transition, respectively. The isoconversional methods of Friedman, Ozawa and Flynn and Wall (FWO), Kissinger–Akahira–Sunose and the Vyazovkin (minimizing) were used to determine the variation of the effective activation energy with the extent of crystallization, Eα (α) and hence, with temperature Eα (T). In addition, the activation energy was calculated from predicted isothermal results. Analysis of the obtained data shows that the activation energy of crystallization is not constant but varies with the degree of conversion and, hence, with temperature. The value of the local Avrami exponent, n (α), varies within 1.88–1.97 for isothermal study and within 2.35–2.4 for nonisothermal process. By using the Johnson–Mehl–Avrami (JMA) model, a good fit was achieved between experimental and theoretical calculation of the reaction (crystallization) rate. The optical energy gap decreased with increasing annealing temperature.

Studying The Structural Properties of Nickle Oxide Nanoparticles Prepared Using Cellulose Extract by Ultrasonic Method For Photocatalyst Application

Nickel oxide nanoparticles (NiO NPs) were prepared using cellulose extract with 1 M NiCH3 salt by ultrasonic method at 600°C. Prepared NiO NPs were characterized by x-ray diffraction (XRD), Filed Emission Scanning Electron Microscopy (FE-SEM). The XRD results confirmed that prepared NiO NPs are crystalline with face center cubic (FCC) and the crystallite sized was 9 nm. FE-SEM measurements show that the particle size of NiO NPs ranges from 40.19 nm to 73 nm with the nano-ball structure. Photocatalytic activity of NiO NPs has been studied through degradation ratio of methylene blue (MB) dye under different illumination time by UV-light. The degradation ratio of MB dye degradation increased from 40% to 90% when illumination time was increased from 15 to 40min.