Papers by Keyword: Iron Oxide

Abstract: This research study focused on the fabrication and characterization of sodium alginate incorporated with iron (III) oxide in the form of beads and biofilm for biomedical application. The fabrication of the samples was carried out by using solution casting method and syringe pump extrusion technique. Beads and biofilm of sodium alginate incorporated with iron oxide were characterized by several characterization testing such as XRD, FTIR and contact angle measurement. From the XRD testing shows the diffraction peak that confirmed the cubic structure of Maghemite. Then, FTIR analysis shows the presence of several intermolecular and intramolecular bond stretching of sodium alginate. Lastly, contact angle measurement exhibits that alginate incorporated with iron oxide has hydrophilic behavior due to the contact angle less than 90Also, it was found that as the contact angle reduced as the weight of iron oxide increased.

Abstract: The research objective is studying the effect of tailing slurry of chromite ore beneficiation on the phase composition and frost resistance of ceramic bricks obtained based on low-melting clay. For the study, two compositions were taken, % wt.: 1) the optimal composition ─ low-melting clay of the Ilek deposit - 70, tailing slurry of chromite ore beneficiation, 2) the reference composition ─ low-melting clay of the Ilek deposit - 100. Raw materials were crushed to pass through a sieve No. 1.0 mm; then, the components were thoroughly mixed. The bricks were prepared by melting at a batch moisture content of 22 %. The mold bricks were dried to a residual moisture content of 5 % max. The dried bricks were fired at temperatures, ^оС: 950 (the glass phase emergence), and 1,050 (the final brick firing temperature). The increased content of iron oxide (Fe₂O₃=12.3 %) and alkali oxides (R₂O=3.2 %) in the tailing slurry of chromite ore beneficiation contributed to the liquid phase emergence at 950 ^оС. Colorless, yellowish, and brown glasses with refractive indices N within 1.50-1.54, forming as a result of melting of spars and mixed-layer clayey formations, were observed under the microscope in the studied prototypes of composition No. 1 at a firing temperature of 950 °C. In the composition No. 2, a liquid phase also emerges, but in smaller quantities. Adding tailing slurry of chromite ore beneficiation to ceramic masses contributes to the formation of anorthite and glass phase in prototypes based on low-melting clay at a firing temperature of 950 °C. An increase in the firing temperature to 1,050 °C increases the content of the glass phase and anorthite, which significantly improves the frost resistance of ceramic bricks.

Abstract: Magnetic nanoparticles (MNPs) have many uses for biomedical applications including drug delivery, magnetic resonance imaging (MRI) contrast agents, theranostics and hyperthermia. MNPs photo-thermally heated by laser light could be used to treat the typically difficult to access tumors such as glioblastomas. Due to their high magnetic saturation, monometallic iron nanoparticles would have an edge over iron oxide nanoparticles currently being investigated for hyperthermia. The goal of this study was to synthesize spherical iron nanoparticles less than 10 nm in diameter by thermal decomposition. The ability of various biocompatible coatings to protect the metallic iron nanoparticles from oxidation was investigated. Coatings studied included Brij, polyethylene glycol and iron oxide. Transmission electron microscopy and Mössbauer spectroscopy were utilized to characterize the coated and uncoated iron nanoparticles’ size and oxidation state to evaluate the effectiveness of the coatings and the procedures in which the coatings were applied. A ferrite shell was found to provide the best stabilization; however, its longer synthesis time increased particle size distribution. Polymer coatings provided biocompatibility but did not prevent oxidation.

Abstract: Magnetic nanofluids are a category of nanomaterial which exhibit simultaneously liquid and superparamagnetic properties. These nanofluids are magnetic nanoparticles stably dispersed in liquid carrier. Magnetic nanoparticles with and without SiO₂ encapsulation have been successfully synthesized by co-precipitation method from ferrous and ferric precursors dispersed in various liquid. Fe₃O₄ nanoparticles were investigated by Zeta Potential and HR-TEM to determine the stability of nanoparticles, average particles size and microstructure of nanoparticles. From zeta potential measurements, is was found that the value of zeta potential for Fe₃O₄ dispersed in ethanol was ± 0,9 mV, while dispersed in di-water was ± 31,1 mV, indicating that nanoparticles Fe₃O₄ are more stable in DI-water. The increasing of zeta potential indicated the adsorption of negatively charged hydroxyl group to the surface of Fe₃O₄ nanoparticles. From XRD measurements, it was found that crystal quality of Fe₃O₄.SiO₂ sintering at 80 °C decreased by increasing the volume of tetraethyl orthosilicate (TEOS), while that samples sintering at 1000 °C have a good crystal quality with hexagonal phase of a-Fe₂O₃.SiO₂. From SQUID measurements, it was found that samples of Fe₃O₄.SiO₂ sintering at 80 °C with TEOS volumes of 1 ml and 2 ml showed a paramagnetic like while samples of a-Fe₂O₃.SiO₂ sintering at 1000 °C with the same TEOS volume showed ferrimagnetic properties.

Abstract: Other portion of solar spectrum apart from UV, particularly blue light, is currently reported to induce the damaging effects to human skin. This study was aimed to investigate the effect of the combination of tris-biphenyl triazine (TBPT) and inorganic metal oxides as well as the effect of the matrix formulations on UV and blue light protection efficiencies. The protection efficiency of various combinations against UVB, UVA and blue light was determined through sun protection factor (SPF), UVA protection factor (UVA-PF) and porphyrin protection factor (PPF), respectively. The results demonstrated that TBPT combined with nanosize titanium dioxide and blended iron oxides (TT60-IR) achieved the highest SPF and UVA-PF. On the other hand, TBPT combined with submicron-size titanium dioxide and blended iron oxides (TT300-IR) yielded the highest PPF value. The matrix formulation affected the scattering property of the filters (i.e. combined TBPT and inorganic metal oxides). Containing the same amount and types of the filters, the matrix formulation that possessed a high transparency property showed high scattering efficiency against the blue light.

Abstract: For the unreacted nuclear model, predecessors have established a more complete theoretical model under the assumption of steady-state conditions. And deduced the general equation of the rate of reduction of pellets. In this paper, we focus on the model of iron ore pellet reduction, not only establishing a single-interface unreacted nuclear model but also establishing a three-interface unreacted nuclear model. The activation energy and diffusion coefficient of iron ore reaction under certain conditions are obtained. According to the fitted images, the speed limit factors in the iron ore pellet reaction model are analyzed completely. In this paper, a pellet decomposition model was established to try to determine the kinetic and thermodynamic parameters of the pellet reaction without the need for experimentation, to simulate the reduction of pellets, and to determine the process of limiting the reaction rate and the process Strengthen.

Abstract: NALCO is mining the bauxite ore of 63.4 lakh tones per annum for the production of alumina 21.57 lakh of tonnes per annum. During mining of bauxite, partially laterized khondalite (PLK) and kaolinised khondalite rocks are excavated and dumped at mining area or can be used for backfilling. The sample ground and classified to recover fines which are suitable for paper industry. Further, the overflow sample is subjected to leaching studies. Leaching studies were carried out at different concentration, time and temperatures. The experiment shows that the optimum conditions are 1.5M oxalic acid, 70oC temperature and 4 hours time. This product can be used as a coating material on paper industry to increase the brightness. The product is fine and no grit present in it. The iron oxide in the product is 0.72% with brightness is 75%. The product specifications compared with BIS standard for raw material using in paper industry. The other characterization of the product indicates that the raw material is suitable for paper industry.

Abstract: Aluminium matrix composites offer improved damping properties than other metals and its alloy. Generally pure metals and its alloys may have fairly good mechanical properties but falls short in damping properties. Aluminium matrix composites are becoming important in aerospace automobile and marine applications due to its god damping properties. The present investigation is concerned with the damping capacity of iron oxide (Fe₂O₃) reinforced aluminium matrix composite. The composites were fabricated with 2%, 4% and 6%, by weight of iron oxide with varied particle of size 40 μm and 500 nm in equal proportions using stir casting process. From the results obtained the 500 nm size with 4 wt% of iron oxide showed improved dynamic properties. The iron oxides reinforced with aluminum matrix are found to be new substitutes for the existing materials with low damping properties.

Abstract: Surface defect is the main form of axle failure. In this paper, the cause of surface defect on wheel seat of a certain type of dynamic axle is analyzed systematically. In the test, the macroscopic chemical component of inspection axle was determined using spectrometer. And the chemical composition near the crack was detected by energy disperse spectroscopy and X-ray photoelectron spectroscopy analysis. The microstructure of the crack area was observed by optical microscope, while the crack microscopic characteristic was characterized using scanning electron microscope and confocal laser scanning microscope. The study found that, the defect is transverse crack, which was distributed circumferentially along the wheel seat. Further more, the typical features of wear or friction and iron oxide was observed on the wheel seat near the crack area. It was concluded that, due to surface presure and the existence of stress concentration, which the wheel and axle interference fit resulted in, wear abrasion and fretting fatigue initiated fatigue crack.

Abstract: The purpose of this study was to absorb the hydrogen sulfide (H₂S) produced by biogas system for local community six absorbents, namely activated carbon, shredded rusty iron and iron oxide-based clay with 4 different size distributions that were tested by employing Completely Randomized Design (CRD). The results showed that iron oxide-based clay from a groundwater supply with smallest size (8.73 mm in diameter) was the most effective absorbent in removing the H₂S judging by security level of biogas users and security level of the engine of 368 and 406 minutes, respectively. However, the security level of the engine of the smallest iron oxide was not significantly different from that of medium size (12 mm in diameter) in 325 minutes. For the durability of absorbent determined from H₂S was less than 500 ppm, the iron oxide with the smallest size was also effective with the best removal (506 minutes) but was not significantly different from those of the medium size (491 minutes) and the mixed size (435 minutes). Therefore, the smallest iron oxide-based clay was selected for the technology transfer to rubber tree farmers and fishermen in the south of Thailand.