21 research outputs found

    Metallic Glasses: A Revolution in Material Science

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    Metallic glasses represent one kind of advanced material, very popular in recent decades. These materials are very adaptable like plastics for their manufacturability in very complex shapes. TPF (Thermoplastic forming) based processes seem very good method to process them. These materials can compete with plastics but have metallic properties. They behave as magnetic materials with less hysteresis loss and less eddy current loss making them suitable for transformer and MEMS (Micro-Electromechanical System) applications. These materials exhibit good corrosion resistance, hardness and toughness. Based on the property and application, metallic glasses are good rivals to plastics, metals and ceramics. Chemical composition and kinetics of supercooling of these materials are the areas where young researchers can focus attention with a view to their improvement

    Recent advances in smart integrated membrane assisted liquid extraction technology

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    Novel processes based on SIMALE have been proposed as effective methods for the selective separation of different chemical species such as metal ions, organic/biologically important compounds and gas mixtures from different waste streams including nuclear waste. The industrial use of supported liquid membranes based on conventional liquids is limited by their relative instability and short lifetime. Under SIMALE techniques, the stability of the SLM is ensured by a modified SLM with pseudo emulsion based hollow fiber strip dispersion or non-dispersive solvent extraction techniques. In order to promote operational stability, SIMALE, using ionic liquids, as a liquid membrane phase could overcome these inconveniences due to their negligible vapour pressure and the possibility of minimizing their solubility in the surrounding phases. SIMALE studies on membrane-based dense gas extraction reported higher extraction efficiencies when the near critical or supercritical solvent is used. This review also discuss important applications including scale up, process intensification aspects, current status of the technology and future directions.Peer ReviewedPostprint (author's final draft

    Plasma Smelting of Iron Ore Fines Having High Silica Content

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    A lot of ore fines are collected at iron ore mines. Till date no measure move is being made for usage of fines for extraction of metallic iron. Generally metallic iron is produced through BFO and DRI processes where particle/ore size and reductant is the most important factor considered for BF charge. The present piece of research work is aimed at use of iron ore fines for production of metallic iron. So there is a process adopted for increasing recovery called agglomeration, which includes pellets and sinter. A newly emerging technology i.e. plasma smelting process is adopted for reduction of iron ore fines. In this project Pellets of iron ore fines (60 % Fe), 8.4% carbon, 0.3%catalyst (containing Al 33%, Ca 20%, Si 5%, Mg 42%) was sintered at 1260 degree centigrade. It is charged to a 35 KW dc arc plasma furnace and smelted for different time lengths i.e. 7, 9 and 13min using argon and nitrogen, as plasma forming gas. The amount of recovery for all samples is measured. Maximum of 93.6 % recovery is achieved. It is observed that use of nitrogen as plasma forming gas increases the rate of recovery than that of argon plasma, due to high energy flux of nitrogen gas which increases the enthalpy due to its diatomicity. The X-ray diffraction analysis shows the presence of ferrite, iron carbide and ferrosilicon nitride phases in the smelted product. Variation of microstructure is observed with the samples. The hardness measurement of different phases on the sample ensured the presence of ferrite, iron carbide and ferrosilicon phases depending on smelting conditio

    Mechanical, Tribological and Hydrophobic Properties Evaluation of Atmospheric Plasma Sprayed NiTi Coating

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    In the current investigation, the atmospheric plasma spray technique was implemented to develop a protective coating of NiTi alloy on the mild steel substrate using different primary gas flow rates and plasma arc currents. For this purpose, an elemental mixture of equiatomic Ni and Ti powder was considered as the feedstock material. After successful deposition, the coatings were characterized using various characterization methods. The physical, mechanical, and tribological properties of the coatings were determined. Furthermore, the plasma spray process parameters were optimized using different optimization tools to achieve the best product. The physical and mechanical properties include the investigation of phase, microstructure, porosity, deposition efficiency, surface roughness, microhardness, adhesion strength, and correlation. The phase analysis revealed the presence of various phases in the coatings, such as NiTi-B2, Ni3Ti, Ti2Ni, Ni, Ti, NiO, TiO, and Ni4Ti3. From the microstructural analysis, various surface and interface defects such as surface microcracks, unmelted/partially melted particles, surface pores, splat fracture, interface porosity, inter-lamellar cracks, vertical cracks, inter-splat cracks, etc. were observed in the coatings developed at lower primary gas flow rates and plasma arc currents. Furthermore, the molten fraction of the powders, thermal pinching effect, enthalpy effect, and air diffusion into the plasma plume influenced the microhardness values of the plasma sprayed NiTi coating. The mechanical interlocking phenomenon of the coating is mainly responsible for the adhesion strength variation of the coatings. The adhesion strength analysis of the coatings depicted various failure modes such as adhesive failure, cohesive failure, mixed-mode failure, glue joint failure, etc. The tribological behavior of the NiTi plasma sprayed coatings was analyzed by the solid particle erosion test performed at two different erodent impingement angles, i.e., 45˚ and 90˚. The results revealed that with the increase in primary gas flow rate and plasma arc current, the erosion rate of the samples eroded with 90˚ erodent impingement angle increase due to the rise in brittle nature of the surface. The lack of edge strength and increase in stress concentration of the coatings having more porosity percentage lead to more damage by the erodents at both the angles of impingements. Furthermore, the surface area of the roughness peaks and the gap between the roughness peaks also influenced the erosion rate of the coatings. Again, due to the difficulty in penetration of the erodent in the surface of the coatings having a higher hardness, the erosion rate is less in those samples. Various wear mechanisms have been observed in the eroded samples, such as plastic deformation, ploughing, microcutting, lip formation, scratches, groove formation, splat fracture, splat fragmentation, splat delamination, pit formation, etc. To optimize the process parameters of the plasma spray coating, in the current work, two optimization techniques were considered. Initially, using the genetic algorithm technique, the process parameters were optimized, and then to validate the obtained result the fuzzy-TOPSIS technique was adopted. From the genetic algorithm, the obtained results revealed the optimized parameters as plasma arc current 550 A and primary gas flow rate as 45 lpm, and the fuzzy-TOPSIS technique also confirmed the same. Also, the primary gas flow rate was the major contributing factor proved by the ANOVA technique. The coating developed at optimized process parameters revealed the superhydrophobic characteristic ensured by the water contact angle 165º and sliding angles 8±10. The surface profile of the coating supports the theory. The coating loses its superhydrophobic characteristics after 90 passes of abrasion in sandpaper. Furthermore, from the annealing, it was observed that the coating retained its superhydrophobic characteristics up to 400 ˚C. The pH test disclosed the sensitiveness of the coatings in an acidic (pH=10) and basic (pH=2) environment. The dropwise evaporation analysis ensured the lower heat absorption of the coating. The coating also has interchanging characteristics in the presence of an electric field

    Calibrating the lives and lived experiences of teachers in India: A plea for research

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    The purpose of this study is to highlight the insufficient understanding of the lives and concerns of government schoolteachers in India, who are often blamed for the deteriorating state of public schools in the country.  It examines previous studies on the subject and contends that they have not adequately represented the teachers' perspectives and voices. In order to gain a more comprehensive understanding of the Indian teaching workforce, it is crucial to conduct research that delves into the personal lives and experiences of Indian teachers. To this end, this review paper adopts a hermeneutic approach to select relevant studies for analysis. We explore the evolution of research on the lives of teachers as a distinct field of study, and introduce several prominent studies in this area to provide a foundation for future research in the Indian context. Ultimately, we identify several key questions that can be addressed through an examination of the lives of Indian teachers

    Hollow fiber membrane-based analytical techniques recent advances

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    Problems of chemical analysis almost always involve two steps; separation of the desired constituent and measurement of the amount or concentration of this constituent. Under the scope of these two steps, sample preparation, proposed analytical technique, and instrumention coupled with analytical system are of paramount importance. Among various analytical techniques, membrane extraction has gained great attention due to its several merits as compared to conventional methods. In all types of membrane extraction, the membrane separates the sample phase (often called donor or feed solution) from the acceptor or strip phase, and the analyte molecules pass through the membrane from the donor to the acceptor. The membrane extraction techniques can be divided into porous and nonporous membrane techniques. Another distinction is between one-, two-, and three-phase membrane extraction techniques.Peer ReviewedPostprint (published version

    Thyroid function test in sickle cell disease: Thyroid function test

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    Abstract OBJECTIVE: This cross-sectional study aimed to evaluate the thyroid function (T3, T4, and thyroid stimulating hormone levels) in patients with sickle cell disease (SCD).  METHODS: This cross-sectional observational study was conducted in the general medicine department of the Veer Surendra Sai Medical College and Hospital, Burla, Sambalpur, Odisha (India). The investigation was performed in the sickle cell clinic, medical ward, and outpatient department (OPD) of the institute. This study was conducted from Nov-2019 to Oct-2021. Sixty-eight patients with SCD were enrolled for assessing their thyroid function. The reference ranges for serum T4 (4.5-12 µg/dL), serum T3 (60-200 ng/dL), and thyroid stimulating hormone (0.3-5.5 uIU/mL) were defined to evaluate the thyroid function. RESULTS:  The average thyroid stimulating hormone, mean T4 level, and mean T3 level among the patients were 4.02, 4.67, and 74.15, respectively. The incidence rates of hypothyroidism and euthyroid status were 23.5% and 76.5%, respectively. While 9.59gm/dL was the mean hemoglobin level, 11-16gm/dL was observed in 42.6% of patients compared to <11gm/dL in 57.4% of patients. Patients within the age group of 14-25 years had a higher incidence of hypothyroidism (62.5%). The differences in hypothyroidism between males and females were statistically insignificant (68.8% vs. 31.2%, p=0.11).  CONCLUSION: Patients with SCD had clinically significant reductions in T3 and T4 levels. In addition, higher levels of thyroid stimulating hormone and reductions in endogenous T3/T4 levels were observed in male patients. Overall, SCD was associated with a higher incidence of hypothyroidism. &nbsp

    Recent advances in smart integrated membrane assisted liquid extraction technology

    No full text
    Novel processes based on SIMALE have been proposed as effective methods for the selective separation of different chemical species such as metal ions, organic/biologically important compounds and gas mixtures from different waste streams including nuclear waste. The industrial use of supported liquid membranes based on conventional liquids is limited by their relative instability and short lifetime. Under SIMALE techniques, the stability of the SLM is ensured by a modified SLM with pseudo emulsion based hollow fiber strip dispersion or non-dispersive solvent extraction techniques. In order to promote operational stability, SIMALE, using ionic liquids, as a liquid membrane phase could overcome these inconveniences due to their negligible vapour pressure and the possibility of minimizing their solubility in the surrounding phases. SIMALE studies on membrane-based dense gas extraction reported higher extraction efficiencies when the near critical or supercritical solvent is used. This review also discuss important applications including scale up, process intensification aspects, current status of the technology and future directions.Peer Reviewe

    Membrane based techniques in analytical applications

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    This article presents an overview of the various membrane-based systems and their role in analytical applications. This includes a systematic review of the various membrane extraction methods used to determine variuos compounds in different matrices in chemical and environmental application

    Membrane based techniques in analytical applications

    No full text
    This article presents an overview of the various membrane-based systems and their role in analytical applications. This includes a systematic review of the various membrane extraction methods used to determine variuos compounds in different matrices in chemical and environmental applicationsPostprint (published version
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