Papers by Keyword: Magnesium Oxide

Abstract: In addressing the gap in sustainable utilization of industrial by-products and the limited exploration of natural antioxidants in nanoparticle synthesis, this study focused on synthesizing magnesium oxide (MgO) nanoparticles using by-products from Melaleuca leucadendra essential oil extraction. The research aimed to evaluate the feasibility of manufactoruing metal nanoparticles with agricultural waste and assesing their properties. The study first tested the antioxidant properties of the water extract of Melaleuca leucadendra leaves, a manufacturing waste from the Melaleuca leucadendra essential oil extraction process, using DPPH and FRAP assays. Green synthesis methods was employed to produce the nanoparticles. The production and properties of the particles were characterize with UV-VIS . Our results indicated that the MgO nanoparticles exhibited antioxidant activity. This study suggests a viable, eco-friendly approach for the utilization of agricultural waste from the Melaleuca leucadendra essential oil extraction.

Abstract: Shear Thickening Fluid (STF) is a highly preferred phase change material that helps in absorbing high impact shock waves and provides excellent protective properties when used along with Kevlar fabric. nanomaterials also offer superior functionality helping in creating many useful, smart and innovative textile fabrics. This research work aims to analyze the synthesis steps, properties and application methods of nanomaterials made from different chemical synthesis methods. The effect of many technical factors and process control parameters is also laid out and found to be important contributors for creating unique fabric property. This analysis provides a guideline to effectively and efficiently use the nanomaterials in the right way and apply the functional nanomaterials using suitable technology for coating which can enrich the functional property of the substrate.

Abstract: The optimized surface morphology of electrospun magnesium oxide (MgO) nanofibers can be achieved based on the parameters set during the fabrication of nanofibers. However, not all materials used during the electrospinning process can be synthesized together as it depends on the application’s needs. This research aims to study the factors that influence the surface area of the MgO nanofibers due to material preparations and electrospinning parameters. The research is based on data obtained from the previous research and was analyzed to evaluate the effect on MgO nanofibers that synthesized with different materials. Based on the data analysis using Brunauer-Emmert-Teller (BET), the surface area for carbon sorbent is higher than organic sorbent. The surface area for carbon sorbent of nitrogen could be achieved up to 324.5 m²/g compared to only 104.8 m²/g using organic sorbent for magnesium oxalate dihydrate (MO). The studies show that the use of nitrogen as a carbon sorbent in the fabrication of electrospun MgO nanofibers may produce a good quality of nanofibers.

Abstract: The effect of 6 MeV gamma photons on thermally stimulated exoelectron emission (TSEE) spectra of MgO films was studied. The films were fabricated on Si/SiO₂ substrates using the extraction-pyrolytic method. The crystalline structure and surface morphology of the films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). TSEE spectra of MgO films had emission peaks at about 450 oC and 525 oC. The area under the TSEE peaks increased after repeated TSEE measurements. In the case of gamma-irradiated films, the percentage increase in the area depended on the radiation dose, decreasing linearly with an increase in the radiation dose from 0 to 80 Gy. The results suggest that gamma radiation reduced the density of trapped electrons present in the as-grown MgO films or created competing hole traps that inhibited TSEE from the films.

Abstract: We reported simple processing of local iron sand in order to increase the purity of magnetic phase. The refining process of iron sand is carried out in two stages, namely the iron sand extract using a permanent magnet and the purification process. The purification process was carried out by co-precipitation method in varying of the dissolving temperatures and volume of HCl. The iron salt solution formed is then precipitated using NH₄OH solution and then sintered at 100 °C and 1000 °C, respectively. All samples are characterized by X-ray fluorescence (XRF) and X-ray diffraction (XRD) to identify the elemental content and the crystal structure. From the XRF measurements, it was found that the Fe content before purification process was 32.68 %, increasing to 33.12 % after purification process with HCL volume of 75 ml and sintered at 100 °C. From XRD measurement, it was found that the crystal structure of iron sand before purification process was dominated by magnesioferrite (33.2 %), and magnetite (20.2 %). After purification process at 1000 °C, the magnesioferrite phase increased to 80.2 % and 50.2 % for HCl volume of 50 ml and 75 ml, respectively, while the magnetite phase increase to become 34.5 % for 100 ml of HCl.

Abstract: Railway brake block is one of the most important components of the braking system of a railway vehicle. Materials for railway brake blocks are commonly made from metal or composite. The metallic brake blocks have some disadvantages that are heavy, low wear-resistant and has potential in generating a spark. While the composite brake blocks do not have those disadvantages. Natural fiber from oil palm empty fruit bunches as the waste from the production of palm oil can be used as a composite constituent. This composite brake blocks made from oil palm empty fruit bunches as reinforcement, phenol resin as matrix, and alumina, magnesium oxide and iron powder as a friction modifier. Density, hardness, coefficient of friction, compressive strength and flexural strength tests were carried out to determine the mechanical characteristic of the composite railway brake block material. The railway brake block test results consist of the density of 1.96 g/cm3, the hardness of 57.6 HRB, coefficient of friction of 0.43, the compressive strength of 37.1 MPa, and flexural strength of 33 MPa. There are three samples of volume fraction combination with 20% of oil palm empty fruit bunch in sample 1, 15% oil palm empty fruit bunch in sample 2 and 10% oil palm empty fruit bunch in sample 3. Percentage of MgO is adjusted to compensate the volume fraction of oil palm empty fruit bunch in the sample. Sample test results show that composite with volume fraction 10% of oil palm empty fruit bunch, phenolic resin of 30%, Al2O3 of 25%, MgO of 20%, iron powder of 15% has better mechanical properties for the alternative composite railway brake block material as compared to the other two.

Abstract: Magnesium oxide (MgO) nanoparticles were synthesized using the sol-gel technique then characterized. Cetyl Trimethyl Ammonium Bromide (CTAB) surfactant was added to reduce Van der Waal forces among MgO nanoparticles and distilled water forming a stable nanofluid using two-step method with aid of ultrasound sonication. Pure distilled water and nanofluids with different volume fractions of 0.25, 0.5, 0.75, and 1% are used as working fluids. Thermophysical properties of prepared nanofluids were measured experimentally and determined theoretically. Effect of solid volume fraction on the thermophysical properties; including thermal conductivity, heat capacity, viscosity, and density of MgO-water nanofluids are discussed. Moreover, experimental results have been compared with the suitable correlations for MgO-water nanofluid. The findings show that thermal conductivity, viscosity, and density of nanofluid increases with increasing solid volume fraction.

Abstract: The surface characterization of MgO thin films was investigated by using surface analysis instruments such as X-ray photoelectron spectroscopy (XPS), reflection electron energy loss spectroscopy (REELS) and ultra-violet photoelectron spectroscopy (UPS). The MgO thin films was prepared on Si substrates by using electron beam evaporation deposited at room temperature (RT) and 300 °C in air. The XPS was used to investigate the effect substrate temperature on the chemical state in the thin films surface. The O1s spectra was showed that the hydrate MgO, Mg(OH)2, was detected in the surface of film at RT and it was decreasing at substrate temperature of 300 °C in air. The band gap obtained for MgO thin films using primary energy of 1500 eV were 6.57 and 7.41 eV for film deposited at RT and 300 °C in air, respectively. The work function of MgO thin films were 4.16 and 4.60 eV for films deposited at RT and 300 °C in air, respectively. Our results suggested that the electronic properties can be improved by the heating treatment during deposition.

Abstract: Low Al single-phase magnesium alloy surfaces with dense magnesium oxide films were uniformly formed. The films were deposited with a radio frequency magnetron sputtering process with a planar magnetron sputtering system. The thickness of deposited magnesium oxide thin films was around 240 nm. According to the XRD results, a magnesium oxide phase film was formed on the substrate. The surface was uniform, and no cracks or exfoliation were observed. The deposited magnesium oxide film did not have any cracks or pores, and the surface of the sample was covered by magnesium oxide. The hardness of the magnesium oxide-coated magnesium alloy reached around Hv200, while that of the uncoated Mg-alloy was around Hv80. Moreover, the Vickers indenter under a 10-mN load indented the magnesium alloy substrate coated with the magnesium oxide film to a depth of around 640 nm, while that for the uncoated magnesium alloy substrate was around 620 nm. Meanwhile, the elasticity value for the magnesium alloy substrate coated with magnesium oxide film was around 5.3×10¹⁰ Pa, while that of the uncoated magnesium alloy substrate was around 4.2×10¹⁰ Pa.

Abstract: The effect of ion irradiation on the strength characteristics of magnesium oxide and ceramics based on zirconia is studied. The MgO samples were a single crystal grown in an artificial manner. Samples of zirconium ceramics were prepared by ceramic technology. Irradiation of MgO crystals was carried out by Si⁺ ions (E = 150 keV), Fe⁺ (E = 70 keV), C⁺ (E = 50 keV) at room temperature. The fluence varied within the range (10¹⁶–10¹⁷) сm^–2. The modification of the investigated types of ceramics was carried out by ions Al⁺ (Е = 60 keV), Ar⁺ (Е= 60 keV), N⁺ (E = 50 keV). We used ion beams of microsecond duration and moderate power (the current density in the pulse was 3 10^-3 A/cm²). Fluence was 10¹⁷ cm^-2. The irradiation of the ceramics with an ion beam C⁺ (E = 50 keV) was also performed with nanosecond duration (τ = 50 ns). It is established that ionic irradiation of magnesium oxide leads to an increase in crack resistance and a critical stress intensity factor. Irradiation of ceramics leads to hardening of its near-surface layers.