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Synthesis of high temperature (1150 C) resistant materials after extraction of oxides of Al and Mg from Aluminum dross
Aluminum Dross (Al-dross) is a well-known Industrial waste generated in an Aluminium industry from the melting of the metal itself. It gets made yearly in hundreds of thousands of tons worldwide, due to the wide use and demand of Aluminum in almost every industry. However, Al-dross is not completely a waste as it contains two compounds of interest, namely Aluminum Oxide (Al2O3) and Magnesium Aluminate (MgAl2O4). They are the basic compounds present in any refractory which are products featuring low thermal conductivity and high temperature shock characteristics in the order of 1000 C+. Thus, Aluminum Dross becomes a vital candidate to be considered for the extraction of the two of the aforementioned compounds. Recent studies have shown that Al-dross indeed can be used to extract Al2O3 and MgAl2O4. However, Al-dross also contains Aluminum Nitride (AlN) a compound that exhibits the exact opposite properties demonstrated by refractories. In addition to being technically unsuitable for use as refractory material, AlN also possesses another huge issue. When Al-dross is dumped into landfills, the AlN present in the dross combines with the moisture in the soil and is energized by geothermal heat which leads into an exothermic reaction, thereby releases highly toxic and health hazardous gases. Keeping the above techno-environment challenges in mind, prior to utilizing the beneficiated Al-dross in any industrial application, it is important to leach out the AlN from the dross in an environment friendly manner. This paper deals with the successive leaching of AlN from the Al-dross using two laboratory procedures. Sintered (to be added) pellets made out of the processed powder in the lab were subjected to analysis of structural phases and chemical constituents by employing XRD and EDS. Cyclic thermal shock test cycles were also carried out by subjecting the pellets to 1150 C and quenching in air alternately, to study the refractory characteristics. 2019 Elsevier Ltd. All rights reserved. -
Performance Evaluation of Area-Based Segmentation Technique on Ambient Sensor Data for Smart Home Assisted Living
Activity recognition(AR) is a popular subject of research in the recent past. Recognition of activities performed by human beings, enables the addressing of challenges posed by many real-world applications such as health monitoring, providing security etc. Segmentation plays a vital role in AR. This paper evaluates the efficiency of Area-Based Segmentation using different performance measures. Area-Based segmentation was proposed in our earlier research work. The evaluation of the Area-Based segmentation technique is conducted on four real world datasets viz. Aruba17, Shib010, HH102, and HH113 comprising of data pertaining to an individual, living in the test bed home. Machine learning classifiers, SVM-R, SVM-P, NB and KNN are adopted to validate the performance of Area-Based segmentation. Amongst the four chosen classification algorithms SVM-R exhibits better in all the four datasets. Area-Based segmentation recognise the four test bed activities with accuracies of 0.74, 0.98, 0.66, and 0.99 respectively. The results reveal that Area based segmentation can efficiently segment sensor data stream which aids in accurate recognition of smart home activities. 2019 Procedia Computer Science. All rights reserved. -
Synthesis and Characterization of Carbon Nanomaterial Derived from Anthracite
Among various storage devices, carbon based supercapacitors grabs the recent trends in the electronic devices. The present research work describes the synthesis of carbon nanomaterials derived from anthracite by using staudenmaier method. Anthracite was used as a precursor because of its high carbon content. The structural and chemical complex formation carried out by using XRD and FTIR confirms the formation of CNT's. The calculated value obtained from the XRD peaks confirms the formation of multilayer carbon nano-materials. The electrode was prepared by coating synthesized CNT on copper rod. The electrochemical performance of prepared working electrode was carried out by using cyclic voltammetric performance. Electrode characterization was performed for different scan rates 10, 20, 30 and 50 mV/sec in a potential window from-0.08 to 0.2V. The CV curves represents symmetric nature which imply that electrode material have stable capacitive process. 2019 Elsevier Ltd. -
Detection and Classification of Potholes in Indian Roads Using Wavelet Based Energy Modules
Maintenance of roads is one the major challenge in the developed countries. The well maintained roads always indicates the economy of the whole country. The heavy use of roads, environmental conditions and maintenance is not performed regularly that leads the formation of potholes which causes the accidents and unwanted traffics. The paper discuss about the detection of potholes based on wavelet energy field. The proposed method mainly includes three phases (A)Wavelet energy filed is constructed in order to detect the image by using geometric criteria and morphological processing (B)Extracting Region of intersect by edge based segmentation technique (C)Classifying the potholes using Neural Network. 2019 IEEE. -
Narrowband and Wideband Directional Beamformer with Reduced Side Lobe Level
In this paper, the synthesis of narrow and wideband beamformers with reduced side lobe level and wide beam steering capability is presented. A closed form expression with slope equalization technique is derived for array factor of the beamformer to meet the desired beam-pattern specifications of Half Power Beam-Width (HPBW)and Side Lobe Level (SLL). The proposed beamformer design is adaptable to any bandwidth and null placement in the desired direction. The slope equalization method improves the SLL of the beamformer. Compared to Kaiser, Chebyshev, DPSS and Taylor beamformers, the proposed narrowband and wideband beamformers exhibit lower and tapered side lobes, hence improved First Null to Last Null (FNLN)ratio. The proposed wideband beamformer exhibits superior performance in the wideband frequency range of 1-3GHz. 2019 IEEE. -
An insight into the superior performance of ZnO@PEG nanocatalyst for the synthesis of 1,4-dihydropyrano[2,3-c]pyrazoles under ultrasound
The investigation presents a straightforward synthesis of fifteen 1,4-dihydropyrano[2,3-c]pyrazoles using ZnO@PEG nanocatalyst in ethanol via Multicomponent approach under the influence of ultrasound. The present methodology successively tolerates a variety of functional groups and offers several advantages such as excellent yields without chromatographic purification, milder reaction conditions, shorter reaction times, and the use of an environmentally benign reusable catalyst. Ecstatically, the reaction was successfully scaled to gram level ascertaining the wider applicability of ZnO@PEG nanoparticles in multicomponent reactions. 2019 Elsevier Ltd. All rights reserved. -
Effect of Temperature on Electrical Properties of Reduced Graphene Oxide (rGO)/Li-ion Embedded Flexible Solid Polymer Electrolyte Films
Reduced graphene oxide (rGO) was synthesized from graphite powder by modified Hummers method. The rGO is emerged with Polystyrene sulfonic acid/Lithium phosphate to prepare PL-rGO solid polymer electrolyte films. The electrical properties of Polystyrene sulfonic acid/Lithium phosphate/reduced graphene oxide composites were analyzed, which is an essential property to obtain the performance, reliability and lifetime of battery with respect to temperature. The mass and charge transfer process that takes place at the interface of electrode and electrolyte was obtained by Impedance analyzer. The Nyquist plots were plotted in the frequency range 1 Hz-35 MHz at different temperatures (30-100OC). The ionic conductivity of PL-rGO polymer electrolyte is 1.4x10-3 S/c.m has been observed for the composition PSSA/Li3PO4/rGO::50:45:05 wt%. The conductivity of PL-rGO composites is directly related to temperature. The hopping of the ions in the PL-rGO is observed by using dc conductivity which follows the Arrhenius relationship. 2019 Elsevier Ltd. -
Self lubricating property of MWCNT in AA2219 composites during high energy ball milling
Revolutions in nanotechnology enabled the development of advanced nanocomposites with superior properties for engineering applications especially in automotive and aerospace industries. Among this carbonaceous nano materials like MWCNT have got more attention. Addition of MWCNT in metal matrix results in retardation of friction coefficient and improvement on other mechanical properties based on its dispersion. MWCNT won't have sufficient space to occupy over the powder surface, when the addition is beyond a limit and acts as a solid lubricant during milling. Investigations on self lubricating property during milling were done by using scanning electron microscope, X-ray diffraction and powder density. Uniform dispersion was the bottleneck to utilize their attractive properties of the reinforcement. An attempt had been done for a uniform dispersion during premixing process using a combination of ultra-sonication, magnetic and mechanical stirring followed by high energy ball milling. 2019 Elsevier Ltd. -
Synthesis of Magnetorheological fluid Compositions for Valve Mode Operation
Smart materials such as Magnetorheological Fluids (MRF) have become sought-after material in wide ranging applications due to the ability to change properties in a controlled manner under application of stimulation such as a variable current, magnetization, heat, force, stress and deformation. Magnetorheological fluids in the rheological fluid domain has found use due to its ability to change its shear strength based on the applied magnetic field. Magnetorheological fluids are composed of magnetizable micron sized iron particles and a non-magnetizable base/carrier fluid. The shear strength of commercially available MRF varies from 0 to 100kPa under the effect of the magnetic field. In a valve mode, the Magnetorheological damper (MR Damper or MRD), the MR fluid flows between two-fixed poles, which are parallel to each other. When the fluid flows between them, due to the applied magnetic field the magnetic particles align themselves in a chain form (on state) which is easily reversible when the field is removed (off state). Physical change of the fluid from liquid to semi-solid is controlled by the magnetic field, which makes the fluid a reliable member in active vibration control applications. In this study, two types of magnetizable particles (Carbonyl iron (CI) and Electrolytic iron (EI)) are taken and characterized using an Anton Paar MCR 702 rheometer set-up, in on and off states. To overcome issues like sedimentation, agglomeration and corrosion of the MR fluid, the iron particles are coated with natural gum like guar and xanthan, to the carrier fluid grease and other thixotropic additives are added. The addition of grease and thixotropic additives will inhibit the microbiological degradation of natural gum over an extended period. These engineered MR fluids are then used to analyze the performance of designed and developed stand-alone MR damper, which is tested using an electro-dynamic shaker. The response and damping performance of the MR Damper is analyzed with controlled changes in variables including percentage of additives in MR fluid & magnetization values 2019 Elsevier Ltd. -
Framework for Controlling Interference and Power Consumption on Femto-Cells In-Wireless System
Utilization of femto-cells is one of the cost effective solution to increase the internal network connectivity and coverage. However, there are various impediment in achieving so which has caused a consistent research work evolving out with solution. Review of existing literature shows that maximum focus was given for energy problems in cellular network and not much on problems that roots out from interference. Therefore, the proposed system has presented a very simple and novel approach where the problems associated with interference and energy in using large groups of femto-cells are addressed. Adopting analytical research methodology, the proposed model offers on-demand utilization of the selective femto-cells on the basis of the traffic demands. The study outcome shows that proposed system offers better performance in contrast to existing approach. Springer Nature Switzerland AG 2019. -
Synthesis and Studies on Partially Stabilized Zirconia and Rare-Earth Zirconate Pyrochlore Structured Multilayered Coatings
This work is focused on the thermal fatigue behaviour studies of ceramic coatings, as TBC (Thermal Barrier Coating) system, its importance in determining the thermo-mechanical properties and service-life estimation of the coatings when exposed to elevated operating temperatures. Commercial 6-8%Yttria stabilized zirconia (YSZ) top coat (TC) and NiCrAlY bond coat (BC) in (a) conventional YSZ (BC and TC), (b) multi-layered functionally graded materials (FGM) i.e., BC-blend (50BC+50TC)-(TC) configuration and (c) lab synthesized Zirconia based pyrochlore (Lanthanum Zirconate-LZ) were the coating materials involved. Nickel based super alloy Inconel 718 substrates were coated by using Atmosphere Plasma Spray (APS) system with three different (varying power) plasma spray parameters. All the sides of the 25mm x 10mm x 5mm thick substrates were completely covered with the bond coat and ceramic coating. FGM configuration was spray coated only on one side of the Inconel flat plates. Thermal shock cycle tests were performed on the coated specimen by following the ASTM B214-07 guidelines which comprised of introducing the coated specimen in a muffle furnace at 1150C, held in it for 2 minutes before removing from furnace followed by forced fan air cooling (one shock cycle). The specimen were periodically subjected to visual inspection for faults, before continuing the shock cycles, until the coating flaked off or cracked or detached from substrate. Cross section metallographic samples were prepared and analysed under SEM (Scanning Electron Microscope) and Energy Dispersive spectroscope (EDS) to study the as-sprayed coating morphology and interface quality, measure coating thickness, study defects characteristics and the chemical composition. Crystal structural phases were analysed using X-Ray Diffraction (XRD). 2019 Elsevier Ltd. -
A Novel Approach to Automatic Ear Detection Using Banana Wavelets and Circular Hough Transform
Ear is an attractive biometric trait that maintain their structure with increasing age. Because of the complex geometry of ear, its detection is very difficult. This paper proposes a modified algorithm for automatic detection of 2D ear images using Banana wavelets and Hough transform. Banana wavelets derived from bank of stretched and curved Gabor wavelets are used to identify curvilinear ear structure. Addition of a preprocessing stage, prior to application of banana wavelets is found to improve the detection results further. The proposed algorithm is brought in to comparison with three existing algorithms and evaluated on standard databases. In addition to manual detection accuracy, this paper also calculates the efficiency of the proposed method using automatic classification techniques. The features like LBP and Gabor extracted from segmented ear image is used by different classifiers to determine whether the segmented portion of the image is class Ear or Non ear. 2019 IEEE. -
Thermal Barrier Coating Development on Automobile Piston Material (Al-Si alloy), Numerical Analysis and Validation
This work is focused on the thermal barrier coating (TBC) development on aluminium-silicon (Al-Si) alloy casting materials, widely used as automobile components (cylinder blocks, pistons etc.). TBCs enable enhanced combustion within the chambers of diesel engines resulting in improved performance and components life. Uniform coating thickness development on complex contours of automobile pistons is a challenging task worldwide which results in varying thermal barrier characteristics across the non-uniform thickness. In consistent (in thickness) coatings are most likely to lead to uneven thermal barrier effects across the TBC thicknesses which directly affect the performance and the lubrication system of the engine. This warrants the development of stable and consistently thick coatings for ideal performance of the Low Heat rejection (LHR) engine. The present research work involved building different thicknesses (100, 125 and 150?m) of commercial 6-8%Yttria stabilized zirconia (YSZ) TBCs on 50? to 75? thick nickel aluminide (NiAl) bond coat. The influence of thickness on thermal barrier characteristics via experimentation and numerical analysis has been studied. Flat plates machined from automobile pistons were used as substrates. The coatings were characterized for thermal barrier effects for hot ceramic surface face temperatures up to 550C (by using oxy-acetylene flame to heat up the TBC surface), structural phase analysis by X-ray Diffraction (XRD) and microstructure analysis in metallographic cross section by employing Scanning Electron Microscope (SEM). An analytical investigation also was carried out to determine the approximate temperature at each interface. A code was developed to calculate the temperature drops across the coated plate and the net heat available at the coated surface using MATLAB. This is important considering the effects, small changes in temperatures will bring on the creep life on the metal. 2019 Elsevier Ltd. -
Effect of MWCNT concentration on microstructures, mechanical properties and sintering behaviour of spark plasma sintered AA2219-MWCNT composites
Uniform dispersion of nano tubes without any structural damage is still a challenge in processing of metal matrix nano composites. Effective dispersion of MWCNT (0, 0.5, 0.75, 1, 2 wt. %) in AA 2219 alloy powder has achieved with a combined effect of premixing process and ball milling. An effort is done using spark plasma sintering (SPS) to consolidate the composites and to investigate the effect of MWCNT concentrations on enhancement of the properties of the composites. Particle boundary clustering was observed on consolidated composites even after a uniform distribution is achieved in alloy powder. Significant improvement in mechanical property is observed by reinforcing with MWCNT. Preferable level of MWCNT for bulk sampling was selected as 0.75 wt. % and 1 wt.%. Addition beyond the limit will cause agglomeration and will act like a lubricant during ball milling. 2019 Elsevier Ltd. -
Experimental investigation on the effect of varying percentage of E-waste particulate filler in GFRP composite laminates
The advent of newer technology increases the electrical and electronic devices into the market in a rapid phase, thereby causing the previous generation gadgets to become obsolete, in spite of the gadgets being in good working condition. This is one of the main causes for the increase of E-waste. In the past two years itself the e-waste has gone up by 8% with respect to weight globally. An attempt is made to utilize the e-waste in a productive manner as a filler material and study its characteristics when subjected to different mechanical tests. This paper describes the fabrication and mechanical characteristics of new polymer composites consisting of E-glass fiber reinforcement along with filler material. Study of composites play a very important role in material science, metallurgy, chemistry, solid mechanics and engineering applications. The specimens were fabricated with the help of hand layup technique followed by vacuum bagging process. Mechanical tests viz., tensile test, Flexural test, and Shore D test has been performed. Samples were made of three different compositions of E-waste filler particulate, 5%, 10% and 15%. These tests have been conducted to find out the impact of varying percentage of filler material on the composite laminates. With the increase in the percentage of e-waste filler, there is a reduction in the tensile strength of the laminate, while the flexural strength of the laminates increased with increase in the filler material. The laminate with 5% filler material exhibited higher hardness than the other two samples. 2019 Elsevier Ltd. -
Synthesis and characterization of graphene filled PC-ABS filament for FDM applications
Present investigation focuses on development of graphene filled PC-ABS filament for Fused Deposition Modeling applications. Compounding and twin screw extrusion was employed to synthesis graphene filled FDM filament of 1.75mm diameter. Percentage of graphene was varied from 0.1 vol% to 0.25 vol% in steps of 0.05. Developed filaments were subjected to SEM studies, dimensional accuracy and density measurements. In order to achieve filament of 1.75mm diameter, filament extrusion temperature was optimized using Taguchi's L25 orthogonal array, microstructure shows homogeneous dispersion of graphene particles in PC-ABS matrix, density decreases with increased content of graphene particles. 2018 Author(s). -
Investigation on thermal barrier effects of 8YPSZ coatings on Al-Si alloy and validation through simulation
In high temperature engineering field, protection of metal components operating at high temperatures has been a problem since the attempts to realize high efficiency aero engines in the 1940s. Researchers have been working on finding a solution for this issue and thermally insulating the surface of the base metal component with a suitable high temperature material, generally a ceramic, is one solution. The Thermal Barrier Coatings, popular worldwide as TBCs have found wide spread applications in aerospace and automobile industry after its successful application in aerospace engines in mid 1970s. In the field of aerospace, generally a super alloy will be the substrate and in automobile field this process is very much suited on aluminium casting alloys, which is the raw material for high speed diesel engine cylinder blocks and pistons. Although a good quantity of research work on TBCs have been completed in the field of aerospace, the published literature on such coatings on Aluminium castings alloys are limited. Present research aims to throw some light in this grey area by plasma spray coating Aluminium-Silicon (Al-Si) substrates with popular Yttria Partially Stabilized Zirconia as top coat and underlying nickel aluminide bond coat. Al-Si alloys are widely used in automobiles. Experiments were conducted to evaluate the temperature drop across a 250 mm thick TBC at different ceramic surface temperatures and then validating the experimental results by simulation in ANSYS. Experimental results and simulated results showed a close match, thereby validating the findings. 2019 Elsevier Ltd. All rights reserved. -
Protection offered by thermal barrier coatings to Al-Si alloys at high temperatures - A microstructural investigation
Thermal barrier coatings, with ~50 mm thick Nickel-Aluminide bond coat and ~250 mm thick Yttria-Stabilized zirconia ceramic top coats were synthesized by Air Plasma Spray coating process on flat plates machined from Al-11Si alloy diesel engine pistons. Coating process parameters and qualifications that were followed were based on previous studies made on the same substrates. The ceramic coatings were subjected to various thermal treatments such as (a) thermal shock cycling tests and (b) continuous heating in a furnace. Uncoated Al-Si samples were simultaneously subjected to the same thermal treatments and used as reference to study the protection offered by the coatings to the base metal substrates. Thermal shock cycles tests involved subjecting the coated and uncoated Al-Si plates to oxy-acetylene flame to allow the ceramic surface to be maintained at 500 C for 1000 cycles (one cycle comprised of heating for 60 s, withdrawal from flame and forced cooling in ambient air for 60 s) and similar thermal shock cycles in an electric furnace. The specimen were also heated in a furnace at 300 C for 1000 continuous hours. Stresses induced during thermal shock cycles and oxidation of bond coat-ceramic coat interface during the exposure to heat are the main reasons for the coating's failure. Details of an investigation on the microstructural changes and oxidation behaviour of the substrate and the ability of the coatings to protect the metal substrates from oxidation are presented. Microstructural studies were carried out by employing a Scanning Electron Microscope attached with Energy Dispersive X-ray spectroscopy facility. The findings were compared on (a) uncoated Al-Si alloy and (b) thermal barrier coated Al-Si alloy with a goal to understand the capability of the coatings to protect the metal from the influences of thermal treatments, at temperatures lower than the melting point of the Al-Si alloy. 2019 Elsevier Ltd. All rights reserved. -
Effect of sonication in enhancing the uniformity of MWCNT distribution in aluminium alloy AA2219 matrix
The present paper investigates the effect of premixing process on the distribution of 0, 0.5, 0.75, 1 and 2 wt.% multiwall carbon nanotubes (MWCNTs) and resultant properties of aluminium alloy AA2219 matrix. Premixing process consists of ultrasonication, magnetic stirring and mechanical stirring. FESEM was used for characterizing the distribution of reinforcement in the matrix. Ball milling with premixing was found to be effective in achieving better uniform distribution of the reinforcement than mere ball milling. Hardness testing of the composite revealed reinforcement of MWCNT enhances the matrix hardness. The thermal stability of composite as evidenced by DTA analysis proved the presence of MWCNT without any structural damages. 2019 Elsevier Ltd. All rights reserved. -
Influence of atmospheric plasma spray process parameters on crystal and micro structures of pyrochlore phase in rare earth zirconate thermal barrier coatings
Yttria-stabilized zirconia (YSZ) thermal barrier coatings is most widely used in gas turbine engines applications and its primary role is to protect the underlying base metal from degradation at its high temperature (>1000 C) service environment. While YSZ serves well in this role, materials with higher thermal stability and lower thermal conductivities are required to be developed for attaining higher operating temperatures and thereby higher energy conversion efficiencies. A number of rare-earth zirconates which form the cubic fluorite-derived pyrochlore structures (A2B2O7) where A: La, Gd, Sm, Ce and B: Zr are being developed, some compositions are more attractive due to their good amalgamation of thermal and mechanical properties. However, when these materials are plasma spray coated on metal substrates, the favorable properties are not immediately realized due to various contributing factors such as poor adhesion/cohesion, microstructure (porosity, defects) or even incomplete stabilization or destabilization of the desired phase (crystal structure) after passing through the plasma. In this paper, plasma sprayable powders of zirconate pyrochlores (or with disordered fluorite structures) synthesized from using La and Ce as the trivalent ''A cation, were plasma sprayed onto Inconel 718 substrates, by using different plasma spray parameters. The considerable influence of these spray parameters on the structural phases (analyzed via XRD) and microstructures (studied via SEM on polished cross section metallographs) are presented in detail. 2019 Elsevier Ltd. All rights reserved.