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Delineation of Parametric Controls on LTCC-Based Eddy Current Sensor Exposed to High Temperature
No full textThe investigation is focused on the parametric evaluation of a microfabricated multilayer planar (MLP) coil exposed to high temperature (HT) (\ge 600 °C). It can potentially be used as eddy current (EC) sensor for in situ structural health monitoring (SHM) of critical engineering components. A detailed analysis of various contributing factors that affect the performance of the MLP coil is discussed. The coil is microfabricated on a ceramic substrate (DuPont L951 green tape) using the state-of-the-art low-temperature co-fired-ceramic (LTCC) technique. The stacked layer configuration (30 layers) soars the performance of the coil in terms of sensitivity and robustness. Emphasis is given on the performance both for dynamic and prolonged static thermal exposure. Delineation of electrical parameters, particularly the series inductance ( ) of the sensor, is found to be stable ( ± 3%) up to 600 °C; beyond which up to 800 °C, there is a decreasing trend ( ± 3%). Also, the sensor shows stable and consistent behavior with a nominal deviation of ±1% during prolonged thermal exposure. These findings throw light on the application of the MLP coil for in situ SHM of critical engineering components exposed to HT
Development of a low-cost copper device for the inactivation of microorganisms in drinking water for human consumption
No full textDrinking water is a basic necessity for mankind in day-to-day life. Due to several environmental changes in the climate, the problem of water pollution and scarcity has increased all over the world, especially in rural and urban areas. To overcome such problems, people are using several alternative techniques for storing drinking water in regular household containers, especially in plastic tubs and plastic buckets, etc. Storing of drinking water in plastic containers increases microbial load with time which leads to various waterborne diseases such as vomiting, nausea diarrhea, dysentery, etc. To address such problems, the present study develops and designs a potable water storage device using copper which will able to reduce water-borne pathogens and can easily fit in any storage container. Experimentation of the developed device was done in both spiked deionized water (DI) (Enterobacteriaceae such as Escherichia coli, Salmonella enterica serovar. typhi, and Pseudomonas aeruginosa) and groundwater samples for analyzing its microbial, and physicochemical (pH, Total Dissolved Solids (TDS), Electrical Conductivity (EC), and copper content) parameters. The results demonstrated that copper devices of 24 and 165 cm2 area can reduce the bacterial population efficiently by 99.99 % in 4 and 8 h in spiked DI and groundwater samples. Copper content was found to be in the range of 0.050-0.095 mg/L (24 cm2) and 0.056-1.75 mg/L (165 cm2) respectively over a period of 0 to 24 h which were characterized using inductively coupled plasma mass spectroscopy. Further, the structural properties of the device were characterized using X-ray Diffraction spectroscopy (XRD). Parameters for the Chick model of inactivation were calculated and evaluated, all of which show the goodness of fit and predictability at various contact times. The developed device finds applications for travelers, households, school children, office goers, etc
Recovery of Lithium (Li) Salts from Industrial Effluent of Recycling Plant
Get PDFTo cope up with the supply–demand gap of lithium (Li) an essential energy
element, the recycling of waste industrial effluent (generated after cobalt recycling
from waste Li-ion batteries) is targeted. In industry, after the recovery of Co, Cu, Ni,
and graphite from one ton of black cathodic material of Li-ion batteries about 8 m3
of waste effluent containing 5–10 g/L Mn and 1–3 g/L Li is generated. Systematic
precipitation studies were carried out using saturated alkaline solution varying Eh/
pH of the effluent. Settling time 30 min and pH ~12 were found to be optimum
conditions for maximum precipitation of Li (~90%) as salt. Precipitation studies for
Mn/ Li with scientific validation were also carried out and discussed. The process
developed has tremendous potential to be commercialized in industry after scale-up
studies
Microstructural evolution and nanoindentation study of magnetic pulse welded Nitinol and Aluminium sheets
No full textThe present investigation involved joining of commercially available Aluminium (Al) and Nitinol (NiTi; 51 at.% Ni) sheets using magnetic pulse welding technique under discharge voltages ranging from 12 to 16 kV and standoff distances from 1.5 mm to 2.25 mm. Primarily, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses have ensured the mixing of parent metals at the transition zone (max similar to 2 mu m wide) in wavy pattern caused by localized heating, especially for the samples welded with 2 mm standoff distance with 14 kV and 14.5 kV discharge voltages. In-depth transmission electron microscopy (TEM) analysis of the transition zone of 14 kV_2mm welded sample has further confirmed the intermixing of (Al, Ni, and Ti) at the transition zone. The selected area electron diffraction pattern from the intermixed layer has indicated nanometric (max. similar to 50 nm) intermetallic (Ni4Ti3) precipitates coherent with the NiTi (B2) phase along with amorphous structure. The refinement of the Al grains adjacent to the intermixed layer has been substantiated with TEM as well as electron back scattered diffraction (EBSD) technique. The nano-indentation study on the welded sample across the weld zone has shown variation in hardness values and pseudo-elastic behaviour of the NiTi, being a primary effect of the stand-off distance. Acceptable joint strength in terms of improved nano-hardness has been found for 2 mm standoff distance, irrespective of the welding voltage, imparted by fine Ni4Ti3 precipitates. Besides, significant amount of pseudo-elasticity of NiTi has been retained at the weld bead as well as at the surrounding location (only 50 mu m away from the weld bead) for the aforesaid welded samples. The pseudo-elastic behaviour of Nitinol is associated with the martensite to austenite phase transformation during the welding process, which has been substantiated with the thermal (Differential scanning calorimetry, DSC) and x-ray diffraction analyses
Effects of Strontium Addition on Corrosion Properties of Al-12Si Alloy
No full textThe microstructural features of binary Al-Si alloys such as eutectic Si morpholo-gy, size and distribution of secondary phases and intermetallic compounds largely govern the corrosion behavior of these alloys. The alloy Al-12Si was investigated for the microstructural and corrosion properties in the absence and presence of strontium (Sr). The alloy modification was done using resistance heating furnace and the alloys were cast into permanent plate molds with Sr content 0.0, 0.05, 0.1, 0.18, 0.25 and 0.35 wt%. The microstructure was revealed by optical micro-scope and electron probe micro analyzer (EPMA)-EDS. The Sr modification re-sulted into the reduced size of α-Al dendrites and fine distribution of Al-Si eutec-tics as compared to the unmodified Al-Si alloy. The coarse script and acicular type eutectics were modified to the fine fibrous structure after Sr addition upto 0.18%. The corrosion behavior of unmodified and modified alloys was investi-gated using electrochemical and immersion test methods in 3.5% NaCl solutions with pH~11. The electrochemical studies were carried out in both static and flow-ing conditions (fluid velocity~ 75 l/min) in Cl- containing medium. The corrosion resistance of the alloy with 0.25% Sr addition was found to be highest amongst all the Sr variants which is attributed to the modified eutectic phase. The corro-sion rates in the flowing medium was several fold the rate observed in static con-ditions and attributed to larger mass transpor
Extraction of Rare Earth Metals from Coal Ash Using Mild Lixiviants in a Single Step Process
No full textThe redemption of Rare Earth Elements from coal ash has multifarious advantages in the utilization of waste and also as a way to minimize unnecessary mining. There is a significant escalation in the quantity of coal ash production, as well as the need for REE in modern-day advanced technological products. The utilization of coal ash, knowing its REE enrichment, has been a persistent area of research and development. Our approach is to extract REEs from coal ash in a non-destructive way utilizing the least quantity of relatively eco-friendly lixiviant. The novelty lies in efficient and selective leaching of REE using milder and less corrosive reagents compared to mineral acids. Our research group is currently engaged in exploring the leaching potential and kinetics of novel organic lixiviants which can leach REEs (similar to 60-70%) using lower quantities (2-10%), preferably in a single step. Interesting findings from our experimental work will be discusse
Effect of Strain Induced Melt Activation Process on the Microstructure and Mechanical Properties of Al-5Ti-1B Treated Al-7Si Alloy
No full textIn this study, simultaneous effects of modified strain induced melt activation (M-SIMA) process and addition of Al-5Ti-1B chemical grain refiner on the casting defects, microstructural features, and mechanical properties of hypoeutectic Al-7Si alloys are investigated. The traditional melting and casting techniques were used to develop cast ingots of unrefined and grain refined structures of Al-7Si alloy. Addition of chemical refiner Al-5Ti-1B to Al-7Si melt could significantly change the secondary dendritic arm spacing and eutectic Si particle size to 31% and 28%, respectively. In the M-SIMA process, cast ingots were 60% warm deformed and heat-treated at mushy zone at temperature 585 degrees C for 30 min. Spherical morphology of alpha-Al grain and fine fibrous type eutectic Si are observed after M-SIMA process. Grain size of alpha-Al and eutectic Si are further reduced to 56% and 40% after M-SIMA process of grain refined Al-7Si alloy. Porosity and micro-cracks are also minimized after M-SIMA process. Microstructural features of cast and M-SIMA processed alloys were characterized through optical and scanning electron microscopy. X-ray diffraction techniques reveal the different phases present in the developed alloy. TEM analysis further confirms the presence of TiAl3 and Ti7Al5Si14 precipitates in grain refined Al-7Si alloy. A significant improvement of 132% in hardness (HV), 76% in yield strength, 120% in ultimate tensile strength, 125% in elongation to fracture, and 116% in specific ultimate tensile strength are obtained in M-SIMA processed grain refined Al-7Si alloy. Fractography analysis reveals the mixed mode of fracture in M-SIMA processed Al-7Si alloy with refined structure compared to brittle fracture of unrefined cast alloy
Characterization and leaching of rare earth elements from Indian coal ash
Get PDFConsumption of critical elements is increasing day by day with the advancement of modern science and technology. Many of the rare earth elements belongs to the class of critical elements and play a pivotal role in modern society. Neodymium (Nd), Europium (Eu), Terbium (Tb), Dysprosium (Dy), and Yttrium (Y) are considered as critical rare earth elements (CREE) for both the short and long term perspective. Lanthanum (La) and Cerium (Ce) are considered as near critical rare earths. Rare Earth Elements (REEs) are consumed in the high-tech industry for the manufacture of various consumer goods such as cell phones, computers, permanent magnets, catalysts, medical devices, etc. Extensive use of REEs is also seen in the manufacturing of wind turbines. To meet the demand in light of restricted distribution of these elements worldwide, it is necessary to recover critical elements from secondary resources. Coal ash is an abundant industrial byproduct of coal combustion due to its large-scale reserves and low cost for energy production. A few ventures have been reported to recover rare earth elements (REEs) from coal-related ash materials in recent years. Coal ash is a very good source for critical elements, as it contains valuable rare earth elements. In this work, a leaching study on two ash samples, formed by the combustion of carbonaceous coal is carried out. The coal samples were taken from the coal mines of eastern region, India. One ash sample contains around 500 ppm REEs, named as Low Total REEs Ash (LTRA) and the other contains around 1000 ppm REEs, named High Total REEs Ash (HTRA). The leaching study was carried out in presence of two different types of acid, i.e. nitric acid (mineral acid), acetic acid (monocarboxylic acid). The leaching efficiency was measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis of the leached solution. For both types of ash samples (LTRA and HTRA), REEs leaching efficiency was observed around 70% in nitric acid. In the case of organic acid i.e. acetic acid, around 30% REEs leaching efficiency was observed for Low Total REEs Ash sample. However, it is observed that, only 40-45% leaching efficiency was there for the High Total REE Ash sample in organic acid
Understanding casting behaviour of low carbon high manganese steel through detailed characterization of mould powder and mould top slag
No full textThis study focused on multistage characterization techniques in developing an understanding of the abnormal casting behaviour of low carbon high manganese (LCHMn) steel. In addition to raw mould powder used for casting LCHMn steel, mould top slag samples were also collected for normal and abnormal casting conditions. Raw mould powder and top slag samples were characterized using XRF, XRD, and SEM-EDS to determine chemical composition, crystallinity and morphology. The chemical composition results revealed deviation of normal and abnormal behaviours from the mould powder due to the pickup of oxides of Al, Mn, and Ti. The SEM analyses of raw mould powder showed different granular particle sizes while pores and glassy/crystalline structure were seen for normal and abnormal behaviour at casting. CaF2, CaSiO3, and Na2CaSi3O9 were revealed as the mineralogical phases. There was a modified crystalline phase present in the abnormal behaviours at casting due to pickup of other oxides
Application of Environmental Friendly Bio-adsorbent based on a Plant Root for Copper Recovery Compared to the Synthetic Resin
Get PDFCopper is one of the non-ferrous metals used in the electrical/electronic manufacturing industries due to its superior properties particularly the high conductivity and less resistivity. The effluent generated from the surface finishing process of these industries contains higher copper content which gets discharged in to water bodies directly or indirectly. This causes severe environmental pollution and also results in loss of an important valuable metal. To overcome this issue, continuous R & D activities are going on across the globe in adsorption area with the purpose of finding an efficient, low cost and ecofriendly adsorbent. In view of the above, present investigation was made to compare the performance of a plant root (Datura root powder) as a bio-adsorbent to that of the synthetic one (Tulsion T-42) for copper adsorption from such effluent. Experiments
were carried out in batch studies to optimize parameters such as adsorbent dose, contact time, pH, feed concentration, etc. Results of the batch experiments indicate that 0.2 g of Datura root powder and 0.1 g of Tulsion T-42 showed 95% copper adsorption from an initial feed/solution of 100 ppm Cu at pH 4 in contact time of 15 and 30 min, respectively. Adsorption data for both the adsorbents were fitted well to the Freundlich isotherm. Experimental results were also validated with the kinetic
model, which showed that the adsorption of copper followed pseudo-second order rate expression for the both adsorbents.
Overall result demonstrates that the bio-adsorbent tested has a potential applicability for metal recovery from the waste solutions/effluents of metal finishing units. In view of the requirements of commercial viability and minimal environmental damage there from, Datura root powder being an effective material for metal uptake, may prove to be a feasible adsorbent for copper recovery after the necessary scale-up studies