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Solid state reaction was employed to synthesize the Bi1−xSrxFe1−xMnxO3 (x = 0.05, 0.10, 0.20, 0.25) ceramic materials. XRD reveals the single-phase rhombohedral structure with R3c space group of the prepared materials. The FTIR spectra have been used to calculate the Fe–O bond length. The UV–Visible diffuse reflectance spectra was used for the calculations of the band gaps, which are found to decrease from 2.02 to 1.83 eV on increasing the Sr and Mn co-doping in BFO. P-E loops were recorded for the samples to determine ferroelectric nature at various applied fields. M-H hysteresis loops show a significant change in remnant magnetization (Mr), saturated magnetization (Ms) and coercive field, (Hc) with Sr–Mn substitution in BiFeO3. From FESEM images revealed agglomerated particles in the samples investigated and an increase in grain size is observed with increase in co-doping in BiFeO3. Out of all the prepared samples, Bi0.90Sr0.10Fe0.90Mn0.10O3 with modified values of multiferroic parameters among the Bi1−xSrxFe1−xMnxO3 (x = 0.05, 0.10, 0.20, 0.25) may be useful as a promising multiferroic material for applications of actuators, sensors and multistate memory devices.

Thick cladding of copper is required for diverse applications, however, only a handful of processes can be used for bulk material cladding. This study has been undertaken to suggest a better alternative method for cladding thick layer of copper on aluminium substrate. Cladding of 3 mm thick layer of copper on 6 mm thick aluminium substrate has been successfully performed using friction stir welding process (FSW). Detailed microscopic study, XRD and microhardness evaluation of the samples proved the quality of clad layer. Interestingly even after three FSW passes no substrate material could reach near the top of clad layer.

Ultrasonic vibration-assisted dry grinding is a sustainable hybrid manufacturing technology that decreases the negative environmental impact of coolant, reduces manufacturing costs, and improves surface integrity. The present investigation analyses the mechanisms associated with ultrasonic vibration-assisted dry grinding of AISI D2 tool steel with an alumina grinding wheel. It also compares the influence of traditional dry grinding and traditional wet grinding modes with the ultrasonic vibration-assisted dry grinding mode at different ultrasonic vibration amplitudes. Ultrasonic vibration was applied to the sample in the longitudinal feed direction. Further, kinematics of the abrasive grit path during the traditional grinding and ultrasonic vibration-assisted dry grinding is presented schematically. In this research, the impacts of ultrasonic vibration amplitude as well as the depth of cut on the process yields such as ground surface topography, grinding force, specific grinding energy, force ratio, surface finish, microstructure, and hardness were investigated experimentally. Experimental results revealed that the highest decline in tangential and normal grinding forces in ultrasonic vibration-assisted dry grinding at ultrasonic vibration amplitude 10 µm and the reduction in surface roughness parameter ( Ra, Rq, and Rz) in ultrasonic vibration-assisted dry grinding was 43.23%, 42.59%, and 33.69%, respectively, in comparison to those in traditional dry grinding and 26.35%, 26.94%, and 27.48%, respectively, in comparison to those in traditional wet grinding. It was observed that ultrasonic vibration-assisted dry grinding is beneficial as the profile produced by ultrasonic vibration-assisted dry grinding has a comparatively flat tip, and profile points are shifted to the bottom of the mean line. This study is expected to assist ultrasonic vibration-assisted dry grinding of hard materials.

The present work focuses on the ultrasonic characterisation of the binary mixture having constituent liquids, 2,3-dichloroaniline and methanol/ethanol, by measuring their density, viscosity, ultras...

Sensitization of the photoanode with the semiconductor quantum dot strongly affects the final performance of the device. In this work, the effect of the adsorption cycle of cadmium sulfide was analyzed for the CdS sensitizer on CdS:TiO2-based quantum dot-sensitized solar cell. The CdS sensitizer was grown on doctor blade-coated TiO2 films using successive ion layer adsorption and reaction (SILAR) method. Porous, well adherent, and pin-hole-free TiO2 films were deposited on fluorine-doped tin oxide-coated substrate. The structural, morphological, and compositional properties of TiO2 and CdS-sensitized TiO2 films were studied using UV–visible spectroscopy, X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The QDSSCs fabricated using CdS sensitizer onto TiO2 photoelectrode were tested for various adsorption cycles of CdS. The influence of various SILAR cycles of CdS sensitizers on the light-harvesting ability of the porous TiO2 photoelectrode and its subsequent highest power conversion efficiency for fabricated QDSSCs were investigated.

Common welding processes that are used for cladding causes dilution and therefore, there is a need to explore new processes of cladding. In this work, friction stir welding process has been used to successfully clad 3 mm thick copper sheet on a 6 mm thick mild steel substrate. The process is different from lap welding, not only because of its intended purpose, but also because several FSW passes are needed to cover the entire surface of the substrate. After one FSW pass, successive passes were carried out to cover a wider width of the clad layer by offsetting the tool. Metallurgical examination of the transverse cross-section of cladded samples was carried out using optical microscopy, SEM–EDS, microhardness test, and XRD. Surface jetting type features, normally seen in explosive welding, were observed at the interface of the two materials. The average grain size of steel substrate below the clad layer for both single and triple passes showed refined grains with size of 3.9 µm and 4.2 µm respectively indicating an improvement of more than 60% over the base steel. Although there was plastic flow of material, the substrate material could not make to the top surface of the clad layer. XRD analysis confirmed no new phases were observed on the top surface of the clad layer after cladding. However, the interface region on the transverse cross-section confirmed the presence of Cu0.8Fe0.2 and Cu0.3Fe1.7 intermetallics. Microhardness for copper clad region remained nearly same across all the passes. However, for the steel substrate, higher hardness values were found near the stir zone due to grain refinement for single pass clad while for double and triple passes, a slight reduction was recorded possibly due to metal transfer across the boundary upon second and third passes.

TiN films with different thicknesses (17.9–102.8 nm) were prepared using rf magnetron sputtering to study the effect thickness on the plasmonic, electrical, and optical properties. X-ray diffraction revealed the amorphous-like structure for thinner films with thicknesses lower than 50.3 nm, whereas polycrystalline of face-centered cubic TiN structure was observed for thicker films. Scanning electron microscopy observations revealed rounded nano-crystallites morphology for TiN films. The EDAX depicted oxygen in the TiN films which attributed to the residual oxygen inside the sputtering chamber and to the partial surface oxidation resulted from the exposure to atmospheric air. As the thickness increased from 17.9 to 102.8 nm, the carrier concentration increases from 1.47 × 1022 to 3.51 × 1022 cm−3 and the carrier mobility increased from 0.091 to 0.489 cm2/V.s, which resulted in a resistivity decrease from 4.65 × 10–3 to 3.64 × 10–4 Ω cm. Two absorption bands around 250 and 1000 nm were observed. The band around 1000 nm was ascribed to the localized surface plasmon resonance (LSPR) and increased with increasing the film thickness. The optical band gap and refractive index values decreased monotonically with increasing the film thickness. It is also inferred that the thickness has a strong influence on the values of real and imaginary parts of the dielectric function. Applying various figures of merit indicated that the prepared TiN films are probably not practical for LSPR device fabrication however they are probably suitable for practical transformation optics and superlens device applications.

A technique is implemented for altering the multimodal resonance generated in an ultrathin silicon ring resonator-based terahertz (THz) absorber. The absorber provides the dual-band resonance with the excitation of magnetic and electric dipole in the lower and upper band, respectively. The field of magnetic and electric dipoles is altered using a non-resonant graphene ring placed in the center of the generated dipolar arrangement and the tunability and perfect absorption is achieved. A circuit model is prepared using transmission line method and absorber operation is verified. The proposed absorber can be utilized as a biosensor for the detection of malaria virus and glucose percentage in water. The sensor offers highest sensitivity as 0.29 and 0.27 THz per thickness unit change and quality factor as 117.53 and 245 in the lower and upper band, respectively during the sensing of analyte thickness. Also, it offers the sensitivity as 0.20 and 0.10 THz per refractive index unit change and quality factor as 105.28 and 211.84 in the lower and upper band, respectively during refractive index sensing. Moreover, the structure remains insensitive to polarization angle of the incident electromagnetic wave.

The present work is focused on the determination of elastic, mechanical, ultrasonic and thermal properties of ScRu intermetallic under the variation of pressure 0–60 GPa and particle size 5–40 nm. Initially, the second order elastic constants (SOECs) have been computed under a potential model approach, in which interaction potential is defined by Coulomb and Born–Mayer potentials. Later on, the estimation of mechanical, ultrasonic and thermo-physical parameters has been performed using SOECs. The ultrasonic velocities are estimated in the same pressure/particle size range for wave propagation along 〈100〉 crystallographic direction. It is found that elastic constants, ultrasonic velocities, Debye average velocity, specific heat at constant volume, thermal energy density, thermal conductivity and melting point enhance with increase in pressure and decay in particle size in chosen intermetallic. The analysis of the obtained results reveals that the elastic, mechanical and thermal properties of ScRu intermetallic shall enhance effectively under pressure in comparison to decay in particle size.

In the present paper, we report the studies on perovskite (CH3NH3PbI3): Zinc Oxide (ZnO) bulk heterojunction (BHJ) photoactive layer (with two different ZnO concentrations) based solar cells fabricated under ambient air. ZnO and NiOx layers are used as the electron and hole transport layers respectively. The typical cell parameters of CH3NH3PbI3: ZnO BHJ solar cells have been calculated and analysed in comparison to that of solar cell fabricated with pristine perovskite (CH3NH3PbI3) based photoactive layer. The best performing solar cell (CH3NH3PbI3:ZnO; 1 mg/ml) has demonstrated highest power conversion efficiency (PCE) of 8.97% and retained 83.82% of its original value after 30 days under ambient air.

Nowadays, precision manufacturing industries are required faster surface inspection tools for the achievement of high productivity. In this context, the Barkhausen noise (BN) technique is adopted as a quick response technique in the grinding for qualitative evaluation of surface integrity of AISI D2 tool steel. Present work investigates the effect of eco-friendly coolant, i.e., cryogenic, on surface integrity of ground sample in the plunge grinding mode at different downfeed and compared with dry and wet environments. Surface integrity was assessed in respect of surface roughness, microstructure, and microhardness. Magnetic response of ground surface was reported by Barkhausen noise analyzer in the form of root mean square (rms), peak, and number of pulses. From the outcomes, it was perceived that no significant variations were found in the microstructure and microhardness of the ground surface and subsurface after cryo-grinding owing to lower thermo-mechanical loading. Besides, lower surface roughness was obtained in the case of cryo-grinding because of thermal softening effect. A linear correlation between BN input parameters, i.e., magnetic field intensity and BN responses at different magnetizing frequency could be achieved. Finally, better BN responses, including higher rms, peak, and number of pulses, were found under the cryogenic environment.

In the present work, optical, electrical, and photophysical properties of poly(3-hexylthiophen)/silver sulphide (P3HT/Ag2 S) nanocomposites thin films were investigated. New amorphous dispersion formula was used to fit the experimental ellipsometer data and it was observed that the both refractive index (n) and absorption index (k) increased for hybrid films compared with pure P3HT film. The photophysical properties of fabricated films were examined by recording the photoluminescence (PL) and time resolved fluorescence spectra. The PL quenching in hybrid films signalled the formation of a charge transfer complex between host (P3HT) and guest (Ag2 S). The fluorescence average life time was noted to drop to 94 ps for hybrid P3HT:Ag2 S 1:2 film compared with 126 ps for pristine P3HT. Finally, the electrical properties of fabricated films were measured using the Hall effect systems. The surface resistivity (ρ) of pure P3HT thin films was found to be 9.70 × 104 Ω.cm, which decreased slightly for Ag2 S/P3HT hybrid films.

This work presents the effect of rotary speed (RS) and traverse speed (TS) on channel characteristics and weld tensile strength during simultaneous channeling and friction stir welding of dissimilar aluminium alloys 6082 and 2024. TS had discernible effect on the location of channels and shifted the same from advancing side to retreating side of weld joint. The effect of TS on channel area was found reverse to that of RS up to mid value of investigated range and beyond that they followed the same trend. RS had more dominating effect on the channel area than TS. The effect of TS and RS on channel perimeter was identical to that on channel area. It is possible to control the shape and size of channels and also their location by selecting proper combination of processing parameters during simultaneous friction stir channelling and welding of dissimilar aluminium alloys.

Deciphering the charge carrier dynamics in perovskite solar cells (PSCs) and electrical merits is essential to further improve the performance and operational stability. We investigated the charge carrier dynamics in triple cation-based PSCs through temperature dependent electrochemical impedance spectroscopy, thermal admittance spectroscopy, and space charge limited current (SCLC). The temperature dependent capacitance versus frequency (C–f) spectra reveal two kinds of activation process, one at low frequency and high temperature (>260 K), and the other at high frequency and low temperature (

The S-type probe or Two holes offset probe is used to evaluate the fluid flow velocity like (dusty air, slurry or mud). When dusty air or mud flow through the L-type probe, the dusty air or slurry gets interrupted at 90° angle of static probe or L-type probe then due to this the static probe is chocked. Therefore, to keep away from this type of blockage. the S-type probe is used. In the present study S-type tube is manufactured at dissimilar angle to maintain the accurate value of coefficient. An experiment done in wind tunnel and to see the impact of different −2 angle of pitot tube on pitot coefficient. In the present study we observed, the coefficient curve values large fluctuate at lower range of velocity from 3 to 14 m/s then larger one. It can be seen that the less variation in pressure with increasing in angle of s type pitot tube.

In this work, machining of Ti-6246 was carried out on EDM using graphite electrode using EDM oil dielectric. The process variables selected were current, pulse on-time and pulse off-time. Design of experiment was based on Box-Behnken Design of RSM technique. Optimization was conducted through desirability approach. Machinability of Ti-6246 work material was evaluated with regards to surface roughness, as better surface quality is requirement for every machined component. It was found that the optimum set of current, pulse on-time and pulse off-time were 4.5A, 50.07 µs and 100 µs respectively. The optimized response parameter achieved was surface roughness of 0.99 µm. Confirmation test were conducted at optimized variables and the value of surface roughness of 1.01 µm was obtained. Values obtained by multi-response optimization and the values obtained by confirmation test were observed to be approximately same.

The current research is mainly focused in finding a viable alternative fuel from bioresources which was furnished by employing Palm oil amalgamated with Aluminum oxide nanoparticles. The biofuel was obtained from primarily non-edible Palm oil by employing trans-esterification reactions. The reactions involved various chemicals alcohol such as Methanol and acid catalyst muriatic acid in order to boost up the reaction rate. Experimental results revealed that the yield obtained with this oil was 95% which can be used for mass production. Further, the comprehensive experimental investigations were performed on performance parameters such as BP, BTE, BSFC and BSEC on single cylinder Petter AV engine running on blends of different biodiesel with diesel fuels. Furthermore, emissions analysis was also performed to study its repercussions on environment. Also, the physiochemical properties of methyl ester produced during the reaction was found to be in accordance with ASTM D 6751 and EN 14214 standards.

Wire electrical discharge machining (WEDM) is most suited for machining conductive materials when precision is required. There are a large number of input control parameters that govern the WEDM performance. Thus, it becomes essential to optimize process control parameters to achieve optimal results. In the present paper process parameter optimization using Taguchi quality design concept of L16 orthogonal array for the wire-cut electrical discharge machining of D2 steel is done. Four process control parameters, namely wire speed, gap voltage, flushing pressure, and current, are analyzed for two response parameters viz surface roughness and material removal rate (MRR). It is found that MRR during WEDM have a predominant impact of current on it, while flushing pressure has the least impact on MRR. Whereas, surface roughness is most effected by wire speed during WEDM and gap voltage has the least impact on surface roughness of D2 steel workpiece during WEDM process.

Ti-6Al-4V alloy is still considered challenging to machine with conventional technology due to low thermal conductivity. To overcome this difficulty due to the material, Abrasive Water Jet Machine is used for the machining needs. The study of the machining process variable (pressure, abrasive throughput, stopping distance and transverse speed) on the response variable (machining time, surface roughness and HRC strength of the finished surface) is considered. L25 (54) orthogonal matrix, conceived in Minitab 18 is taken to carry out experimental work and the same is statistically analyzed with Taguchi Technique. The pressure appeared to be the most influential input variable for processing duration and surface roughness. The hardness is influenced as much as possible by the abrasive flow caused by the incorporation of particles into the material.

EDM is an electrical discharge machining, used in machining of those constituents which are not machined by traditional machining process. This machining method is more advanced than conventional. In this experimental study, cylindrical copper material is used as an electrode, and die-steel is used as workpiece material. In this empirical work, results were found for the erosion of copper electrodes concerning to die steel workpiece material at various current and constant depth of machining by varying time-on and time-off parameters. In this work input parameters are current, voltage, T-on, and T-off, and output parameters are erosion of electrode material in terms of weight (grams) and length (mm). The eroded metal on the surface of both workpieces and the electrode is flush out by the dielectric fluid. This study mainly concentrates on the copper electrode and output parameters such as rate of wear of the electrode. Electrode wear rate have increased with an increase in pulse on time. More wear is occurred due to increasing of duration of sparking time. The production of the high rate of material removal is increased by pulse on time (T-on).

This research gives an explanation that has been made to establish a model (thermal) that has operating solar still that have condensing cover in conical shape for the suggested photo-voltaic thermal compound parabolic concentrator. This model is completely depending on simplified equation of energy balance of each and every element of the suggested structure. A sensitive parametric investigation to check performance of the photo-voltaic thermal compound parabolic concentrator operating solar still of conical shape in form of climatic and design specification has been studied. The numerical simulations have been performed by using MATLAB for month of March in climate of New Delhi. There are various parameters that affects the packing factor of photo-voltaic thermal compound parabolic concentrator, absorptivity of basin liner and depth of basin of water on suggested operating solar still performance have been explored in details. From the results and discussion, it is found that the output on daily basis of the proposed system is inversely proportional to depth of water basin and directly proportional to absorptivity of basin liner.

In recent years, increasing demand for biodegradable lubricants has been observed in precision machining owing to ISO 14000, which draws more attention toward the operator’s health and environmenta...

Cadmium Sulfide (CdS) is an excellent semiconductor for photonic devices and its optical and electrical properties are greatly affected by single element doping. In the current manuscript, the effect of potassium ion (K+) doping on linear and nonlinear optical traits of spray pyrolysis deposited CdS films was investigated. The X-ray diffraction (XRD) spectra reveal the increase of defects, decrease of crystallinity and crystallite size also change in growth orientation with K+ doping in CdS films. Moreover, the position of FT-Raman peaks was slightly blue shifted and morphology of films shows clusters of agglomerated CdS nanoparticles along with small size nanoparticles in the background as revealed from SEM images. The bandgap of K+-doped CdS films slightly broaden and shows improved transparency as compare to pure CdS films. The dielectric constants were found to be first decease for 2.5% wt. K+ doping and thereafter slightly increase for 5.0% wt. CdS films whereas optical conductivity decrease for all K+ doping concentrations. The photoluminescence intensity of CdS decreases and slightly blue shifted upon K+ doping, also a new emission band appears at 630 nm, indicating formation of new trap states in the bandgap of semiconductor. The 3rd order nonlinear properties elucidated through Z-scan technique reveals the increase of n2 and χ3 whilst decrease of β with increase of K+ content in CdS thin films.

In this work, crystalline two-dimensional (2D) tungsten disulfide nanodisc-like structures (1T-WS2) and its nanocomposite with graphite sheets synthesized using a facile two-step solvothermal procedure for photoelectrochemical (PEC) oxygen evolution reaction (OER). The XRD patterns revealed the existence of WS2 (1T phase) crystalline structure. Both WS2 nanodiscs and graphite were ultrasonicated to exfoliate the sheets and the suspension was solvothermally treated to design a WS2/graphite (WS2/G) nanocomposite. Fascinating flower-like nanostructures composed of nanodiscs observed during the detailed morphological investigation. The FE-SEM observation demonstrated well-dispersed graphite sheets in WS2 nanodiscs. The photoelectrochemical water splitting performance of bare WS2 and WS2/G hybrid photoanodes investigated under simulated 1 SUN irradiations revealed threefold increase in the photocurrent density of WS2/G hybrid photoanode compared to WS2.

The development of a stable integrated photo-electrocatalytic (PEC) systems for hydrogen production from water is poised to reduce global CO2 emission. While some PEC systems have reached efficienc...

Nowadays, Minimum Quantity Lubrication (MQL) technique with eco-friendly groundnut oil is adopted in precision machining to tackle the operator health and environmental issues owing to petroleum based cutting fluid. The effectiveness of this technique depends on mixture quality of MQL mist. Hence, the objective of present work is to optimize the MQL mist parameters i.e. air pressure (P), flow rate (Q), and stand-off distance (ds) to minimize the effect of MQL based plunge grinding on hardened AISI H13 tool steel in terms of lowest grinding force, specific energy, grinding temperature, and surface roughness using grey relational analysis. Taguchi’s L16 orthogonal array was utilized for conducting the final experiments and mist parameters varied through four levels include P (2, 3, 4, and 5 bar), Q (50, 100, 150, and 200 L/h) and ds (40, 50, 60, and 70 mm). Further, experimental analysis was carried out to compare the effect of optimal and worst mist parameters on ground surface and microchip by using microhardness, scanning electron microscope, and atomic force microscopy. According to validation test, P: 4 bar, Q:200 mL/h, and ds:50 mmare optimal mist parameters for multi-response variables of MQL grinding. Effective mist quality i.e. average droplet size of 51.03 μm was obtained at nozzle angle of 12°. Excellent ground surface quality with negligible microhardness variation and no wear tract microchip were observed under optimal mist setting.

A novel apparatus has been designed, simulated and fabricated to harness solar energy for indoor solar cooking and day lighting purposes. Herein, a fixed orientation collimated beam of concentrated sunlight has been achieved irrespective of the sun’s position using three optical components, viz. concentrator, reflector and collimator with a dual axis tracking system. Two different designs were simulated using optical ray tracing simulations and the optical output was compared. The first design uses a paraboloidal reflector while the second design uses a Fresnel lens as concentrator. Simulation results show that the first design employing paraboloidal reflector has 52.5% optical loss just after the collimator and 52.9% loss at a 4 m distance from the collimator. Similarly, the second design has 50.6% optical loss just after the collimator and 61.8% loss at a 4 m distance from the collimator. The prototype of the Fresnel lens-based design with automatic dual axis tracking was fabricated and the system was tested from morning to evening. Stationary focal spot was observed throughout the day irrespective of the sun’s position demonstrating the feasibility of the system for transporting solar energy for indoor applications. Optical loss of the prototype system was measured and was compared with the simulation results. Optical loss for the prototype just after the collimator was found to be 61.6% which is in good agreement with the simulation results. Thus, the developed novel system can be used as an alternative and clean source of energy for indoor solar cooking and day lighting applications.

Thermal damage restrict the capability of grinding in achieving the desired production rate; therefore, the present study focuses on the employment of a non-destructive Barkhausen noise (BN) technique in the assessment of thermal damages produced from grinding of hardened IS 2062 steel under dry (no lubrication) and wet (with lubrication) conditions. Optical microscopy along with microhardness measurement was utilized to reveal the microstructural and hardness alternation occurred in the ground and subsurface of sample. X- ray diffraction peak shift was measured and used for qualitative analysis of residual stress. Furthermore, surface topography was obtained by scanning electron microscope. The magnetic response from ground surface were measured in terms of Barkhausen noise (root mean square) and hysteresis loop (average permeability). The result shows very poor magnetic response from ground hardened steel due to higher carbon content. A non-linear variation is observed between peak shift and root mean square value of Barkhausen noise. However, average permeability derived from hysteresis loop shows good correlation with the peak shift with a correlation coefficient of approximately 0.8149.

A double-gated single-electron transistor (SET) based on metal–organic complex vanadium tris(dithiolene) has been modelled and investigated for the operation and electrostatics analysis. Density functional theory and non-equilibrium Green’s function method have been opted for first-principle calculations. For the enhancement of the electrostatic control in the SET operation, an addition of a second gate to the basic configuration of SET has been implemented. The results of the energy calculations have shown the expected enhanced electrostatic control in the SET operation with the incorporation of the second gate. The total energies are used to calculate ionisation energy, affinity energy and addition energies, and have shown reduced values for the double-gated SET. Total energies are also used to plot charge stability diagrams and energy surface plots for different gate voltages, which depict the improved conduction process. Because of its sensitivity towards the molecule’s individual charge states, the resultant double-gated SET can be used as a charge sensor.

The variation of magnetic Barkhausen noise (MBN) response of different regions of the gas metal arc welded ferritic stainless steel SS409L plate in terms of number of pulses and root mean square value with the variation of MBN analysis parameters (magnetic field intensity and magnetizing frequency) have been investigated in the present work. Five different values of magnetic field intensity 250, 500, 750, 1000 and 1250 Oe at the constant magnetizing frequency of 25 Hz and four different values of magnetizing frequency 10, 20, 30 and 40 Hz at a constant magnetic field intensity of 800 Oe were used as MBN analysis parameters. It was found that MBN response depends upon the magnetic field intensity and magnetizing frequency as well on grain size and microhardness of different regions.

Hysteresis loop analysis technique, being a non-destructive testing technique is more beneficial than the destructive testing techniques to characterise the welded plate. In this study, the ferritic stainless steel AISI 409L plate was butt welded by gas metal arc welding process. Hysteresis loop analysis technique was used to study the microstructures and microhardness of the base metal region, heat affected zone and weldmetal zone. This study has been carried out at four different values of magnetic field intensity 250, 500, 750 and 1000 Oe. The effect of variation of magnetic field intensity on the hysteresis loop characteristics (average maximum flux density and core loss) has been investigated for base metal, heat affected zone and weldmetal zone. It was found that for each region, the average maximum flux density as well as core loss increases on increasing magnetic field intensity. Also, the variation of average maximum flux density is inversely proportional to the microhardness of the region at each value of magnetic field intensity.

Flow past a microfluidic cylinder confined in a channel is considered as one of the benchmark problems for the analysis of transport phenomena of complex fluids. Earlier experiments show the existence of an elastic instability for the flow of a wormlike micellar solution in this model system after a critical value of the Weissenberg number in the creeping flow regime (G. R. Moss and J. P. Rothstein, J. Non-Newtonian Fluid Mech., 2010, 165, 1505-1515; Y. A. Zhao et al., Soft Matter, 2016, 12, 8666-8681; S. J. Haward et al., Soft Matter, 2019, 15, 1927-1941). This study presents a detailed numerical investigation of this elastic instability in this model system using the two-species VCM (Vasquez-Cook-McKinley) constitutive model for the wormlike micellar solution. Inline with the experimental trends, we also observe the existence of a similar elastic instability in this flow once the Weissenberg number exceeds a critical value. However, we additionally find that the elastic instability in this model geometry is greatly influenced by the breakage and reformation dynamics of the wormlike micelles. In particular, the onset of such an elastic instability is delayed or even may be completely suppressed as the micelles become progressively easier to break. Furthermore, this elastic instability is seen to be associated with the elastic wave phenomena which has been recently observed experimentally for polymer solutions. The present study reveals that the speed of such an elastic wave increases non-linearly with the Weissenberg number similar to that seen in polymer solutions.

Non-conventional Electrical Discharge Machining (EDM) is popularly employed technique for the manufacturing of miniaturized items with high degree of accuracy and precision. In this process, the dielectric fluid plays a major part in influencing the machining parameters. Conventionally, hydrocarbon products were used as dielectric fluid during EDM operation. The most common of them is kerosene. Health of the operator and environment need to be given importance when hydrocarbon based dielectric fluids are used. Since, they produce harmful emission, vapors and aerosols during the process. Further, non-biodegradable waste products are also produced. To conquer these issues, alternate dielectric fluid is needed. In this work, feasibility of using jatropha curcas oil based biodiesel (JCOB) as sustainable dielectric fluid during EDM operation has been thoroughly investigated. Dielectric fluid and its important function have been discussed in detailed. It is suggested that JCOB can be viably employed as dielectric fluid.

Characterisation of the welded plate by Non-destructive testing technique are gaining more popularity over destructive testing. In this study, the variation in the hysteresis loop behaviour were examined with the variation of magnetic field intensity on the base metal, heat affected zone and weld metal regions of gas metal arc welded ferritic stainless steel plate. The behaviour of hysteresis loop characteristics such as average permeability, remanence and coercivity have been investigated and it was found that these characteristics depend upon the grain size and microhardness as well as magnetic field intensity. Coercivity of each region vary in proportion with the variation of magnetic field intensity and inversely proportional to the grain size, but the variation of other hysteresis loop characteristics with the magnetic field intensity in each region is irregular.

The use of photocatalysts for the degradation of synthetic and organic pollutants, such as dyes and chemicals, has emerged as an effective method for wastewater treatment. In this review, we have focused on photocatalytic materials that are based on two-dimensional carbon nanostructures, like graphene oxide (GO) and reduced graphene oxide (RGO), which possess high levels of oxygen functionalities, large surface areas, and effective adsorption sites. Composites containing GO/RGO show suppressed electron–hole-pair recombination rates and reduced energy gaps due to valence band level (VBL) and conduction band level (CBL) modifications, resulting in the better adsorption of light radiation and enhancement in the photodegradation performance of metal-oxide- and polymer-based composites. This review is the first attempt to comprehensively explore the photocatalytic activity effects upon the loading of GO/RGO with metal-oxide- and polymer-based composites. Moreover, the effects of pH, initial dye concentration, photocatalyst dose, and composite surface charge on effective degradation have also been examined.

Green sand is used for making molds to obtain the desired casting in foundries. The process is associated with solidification of molten metal that results in the evolution of the latent heat of fusion. The clay used for binding purpose is decomposed to various forms depending on the local temperature. It is thus necessary to determine temperature distribution in the molds such that much of the sand that is intact can be saved and recycled as it is. This paper studies the heat transport in the mold to obtain the spatio-temporal temperature profile in the green sand mold. Furthermore, the impact of the heat of molten metal on sand properties (loosely bound clay/oolitic deposits) was also quantified as it is known that clay decomposes at a temperature >773 K. The clay and oolitic content were found to be varying across the used mold. The values of loosely bound clay and oolitic content were found to be 1.8% and 9.2%, respectively, at a distance of 0.1 cm away from the casting face while at a distance of 12 cm they were 10.95% and 0.6%. It was observed that only 15% volume of the mold was affected owing to the heat of the molten metal for a 10 kg casting. COMSOL-Multiphysics software was used to predict and validate the temperature distribution in the mold. The results agree reasonably well with the experimental findings. A careful demolding process would thus prevent a huge amount of sand from going to dumping land.

In the present work, analysis of concrete pavements using ANSYS software has been attempted. ANSYS is a finite element method-based software. The concrete slab has been modeled with solid 45 brick element and spring elements for soil. Analysis was carried out for a wide range of load and slab soil combination. The soil as “Winkler type” represented by elastic springs and their stiffness was derived from modulus of sub-grade reaction. The influence of any particular base or sub base on edge stresses was not studied here. The model will be then subjected to number of varying input parameters like the change in the thickness of pavement slab, sub-grade material to winkler foundation, modulus of elasticity by adding metal chips in different percentage like 10%, 20%, 30% and also intensity of loads. It is aimed to compare the stresses of the model study with classical approach of Westergaards and IRC 58- 2002 method. Westergaards equation under estimate edge wheel load stresses when compared with those obtained from ANSYS. For generating the charts, edge loading condition was considered which is critical case for wheel load stresses. Also, it was aimed to compare the results with those given by IRC 58 – 2002 design charts. Design charts were developed in thesis work yield the same value of pavement thickness as that of IRC 58 – 2002 method.

The present work reports an experimental investigation of heat transfer characteristics of a closed-loop two-phase thermosyphon (CLTPT) system with a structured heating surface. A novel structured heating surface, i.e., segmented finned microchannels, has been used to promote heat transfer rate, and its performance has been compared with that of plane heating surface. Compared with the plane heating surface, the segmented finned structured heating surface produces an enhancement of 157% in heat transfer coefficient (HTC), whereas it produces a 145% enhancement in the critical heat flux (CHF). The present structured surface also delivers better heat transfer performance compared with the available data in the literature.

Since the sun is a usable source of energy available throughout the year and can be used effectively for electricity production. However, owing to the reflection at the interface of air and the top surface of the photovoltaic (PV) module and some time the deposition of dust on the panels, a substantial percentage of solar energy is wasted. As a result, multipurpose slim coatings or layers have been used in recent times to improve the surface morphology and characteristics of solar panel surfaces to improve their energy transmittance, self-cleaning, antireflection, and antifogging properties of the PV modules. This research talks about the super hydrophilic surface coating for the solar PV module. Some of the main roles that super hydrophilic coating contributes are being discussed here, such as improved solar panel efficiency, greater power accumulation, and self-cleaning properties. In recent years, TiO2 based hydrophilic coating has been extensively studied. This oxide has a few constraints since it diminishes the glass conveyance and it quickly restores the water contact angle in dim conditions. In this chapter, major characteristics, principles, techniques, methods, advantages, and disadvantages of TiO2 based super hydrophilic coating for PV modules has been discussed.

The importance and utilization of advanced thermal insulating materials increase due to their broad and irreplaceable energy conservation role. This paper describes the novel way of achieving insulating material. In two waste by-products, namely rice husk ash (RHA), agriculture waste, and marble waste powder (MWP), industrial waste has been utilized to make asbestos-free advanced material for thermal insulation. A novel method for making asbestos-free advanced material for thermal insulation using RHA and marble waste’s inherent characteristics has developed mechano-chemical for appropriate physico-chemical consolidation, densification, and ceramic processing route. The Si and Ca sources undergo a series of chemical transformations accompanied by mass transfer and thermal reactions during the synthesis process. The formation of this silicate compound occurs due to the presence of higher contents of CaO in marble waste powder (MWP) and silica in rice husk ash (RHA), resulting in thermal insulating characteristics in the advanced thermal insulation material (ATIM). Raman spectra of ATIM after heating at 1100 °C were mainly amorphous, which had a broad peak at 1072 cm−1. This shows thermal transformation occurs after the heating process, the admixture of tailored powder, and fly ash (FA). The density of the ATIM is found to be 1150 kg/m3. The phase transformation (glass transition temperature) was found in all the samples between 600 and 800 °C. The mechanical properties, namely the compressive strength and impact strength evaluation test, showed that the material meets the standard specifications for ceramic tiles. The thermal conductivity (W/mK) was calculated from different temperature 30, 50, 100,150, and 200 °C and found to be 0.571, 0.541, 0.516, 0.498, and 0.477, respectively. According to the test results, it is concluded that ATIM from MWP, RHA, and FA were excellent insulating components. The novel feature of the reported process is the development of non-toxic and asbestos-free thermal insulating low-cost material wherein chemically designed and mineralogically formulating desired phases lead to the homogeneous and effective thermal insulating matrix. The process is feasible, simple, cheap, and highly energy-efficient, increases production efficiency, and is environmentally friendly. The widespread use of advanced material for a broad application spectrum ranges from aerospace, automobile, electronics, transportation, construction, to other industries.

In this paper, the Transport Coefficient of SO 2 gas are calculated from swarm model design using BOLSIG+ which is user-friendly open-source computer program based on numerical solution of Boltzman equation (BE) up to two-term approximations. To ensure close agreement of calculated transport coefficients for SO 2 gas with impending experimental works, first we calculate these coefficients for SF 6 , and CO 2 compared the results with reported values. Reasonable agreement is found between calculated and report transport coefficients. For realistic acceptance of SO2 gas as SF6 alternative in long-term for high voltage applications, we discussed the utilization of these coefficients in study of various electrical breakdown related phenomenon to understand its dielectric and electrical insulating behavior during electrostatic discharge. We also predict numerical values of insulating properties in uniform electric field under steady state conditions such as electric strength, breakdown voltage and ionization constant for SO 2 gas using transport coefficients. For SO 2 gas, some of these properties and values are being calculated for first time.

An experimental study was conducted to evaluate the effect of addition of alkali, salts and surfactants on the rheological properties of polyacrylamide (PAM) solution by rheometry. The results show the addition of inorganic salts (NaCl, Na2SO4, MgCl2), alkali (NaOH) and surfactants (CTAB, Gemini-5 and Gemini-6) strongly influence the rheological behavior of polyacrylamide solution. The shear thinning behavior of the solution at low shear rate was observed. The scope of this experimental work also includes the measurements of viscoelastic behavior, transient shear stress response and yield stress. The results are quite interesting and the mixed systems can be used as ASP flooding in Enhance oil recovery.