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Copper-steel welded joints are now used widely in heat exchangers, piping and power generation industries. Owing to their different thermal characteristics, sound welding of the pair is a challenging task. Extensive research is carried out to achieve successful welding of copper and steel. This article presents an insight into the works done on the joining of copper and steel by various techniques. The microstructural modifications in different approaches are critically presented. Mechanical properties of joints obtained through different techniques are compared.

In crossbred cattle bulls, poor seminal quality and freezability are major constraints. The present study was conducted to determine semen quality parameters of Vrindavani crossbred bulls. In this study 130 semen samples were collected from five Vrindavani crossbred bulls. The volume, mass motility, concentration and individual progressive motility, viability and abnormality of spermatozoa were examined. Then ejaculates were categorized into four groups on the basis of spermatozoa concentration and individual progressive motility. The percentage of normozoospermia, asthenozoopsermia, oligozoospermia and oligoasthenozoospermia ejaculates were 44.62%, 29.23%, 11.54% and 14.61%, respectively. The overall mean of volume, mass motility, concentration of spermatozoa, individual progressive motility, viability and sperm abnormality in semen ejaculates of crossbred Vrindavani bulls were 4.64±0.63 mL, 2.48±0.09, 772.20±27.95 million/mL, 65.08±1.47%, 79.94±1.07% and 7.82±0.44%, respectively. Ejaculate mass motility, concentration, progressive motility and abnormality of spermatozoa varied significantly (p

The present work aims to investigate thermal performance of a solar flat plate collector using water and Cu-MWCNTs nanoparticle-based hybrid nanofluid both experimentally and numerically. X-Ray diffraction, FESEM with EDAX mapping were performed to characterize nanoparticles. The experimental setup was developed for thermal performance of FPC varying flow rates (0.5, 1.0, 1.5 lpm), inclination angle (25°, 30°, 35°, 40°, 45°), volume concentration (0%, 0.1%, 0.2%, 0.3%, 0.4%) and intensity (400 W/m2). The 3D numerical model having similar geometry as of actual flat plate collector was modeled using Fluents 15.0. The SST turbulence model was used to capture the chaotic changes in the velocity, temperature, and pressure fields. The experimental findings revealed 79.74% improvement in instantaneous efficiency at 0.4% vol., 1.5 lpm, 45° inclination angle, and 400 W/m2 intensity. The maximum deviation between the experimental and numerically calculated outlet and inlet temperature difference (ΔT) was 3.5% using a hybrid nanofluid. When numerical data are compared, instantaneous efficiency and heat gain both deviate by 2.8% and 2.9% from experimental values. Because of the numerical simulation analysis, it is possible to observe the temperature and flow pattern in flat plate collectors using nanofluids under a set of operating conditions, which would not be possible without the simulation.

Oxidative stress is one of the leading factors responsible for poor post-thaw semen quality because of overproduction of reactive oxygen species (ROS) over neutralizing antioxidants present in semen. Mainly two ROS generation sites are present in spermatozoa, that is, mitochondria and plasma membrane. Therefore, the idea of targeting these specific sites for minimization of ROS production with the compounds having known mechanism of actions was built up as a core for this research.Present study was done to investigate the effects of Mito TEMPO and acetovanillone individually and in combination on freezability of buffalo spermatozoa.For the experiment, semen extender was supplemented with Mito TEMPO (50 μM), acetovanillone (50 μM), and a combination of Mito TEMPO + acetovanillone (50 μM+ 50 μM), designated as Group II, Group III, and Group IV, respectively. Control group without any supplementation was designated as Group I. A total of 24 ejaculates with individual progressive motility (IPM) of ≥70% were selected for the study. After final dilution, filling-sealing of straws, equilibration, and freezing were done as per the standard procedure. Semen samples were evaluated for IPM, plasma membrane integrity, lipid peroxidation, total antioxidant capacity (TAC), and cholesterol to phospholipids (C/P) ratio at both fresh and post-thaw stages. Evaluation of ROS, mitochondrial membrane potential (MMP), capacitation status (CTC assay), and in vitro fertility potential were conducted only on frozen-thawed samples.The addition of Mito TEMPO (50 μM) and acetovanillone (50 μM) individually and in combination significantly (p 0.05) improved post-thaw semen quality in terms of IPM, plasma membrane integrity, TAC, cholesterol content, C/P ratio, MMP, Chlortetracycline (CTC)-Full (F) pattern, and zona binding ability of buffalo spermatozoa, while significantly (p 0.05) reduced ROS production, lipid peroxidation, and capacitation like changes as compared to the control group.As Mito TEMPO acts as an SOD mimetic and also detoxifies ferrous iron at the mitochondria level, it aids in neutralization of excessive ROS production and minimizes oxidative stress-related damages that enhances the antioxidant potential of sperm mitochondria. Earlier studies also indicated improved post-thaw semen quality in 50 μM supplemented group. The improvement observed in acetovanillone (50 μM) group might be because of inhibition of Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase as this enzyme activation by various physical/chemical inducers during cryopreservation process leads to activation of CatSper channel resulting in calcium influx, premature capacitation, and acrosomal reaction like changes through activation of adenylate cyclase and cAMP/PKA-mediated tyrosine phosphorylation of sperm proteins. Acetovanillone also prevents NADPH oxidase-mediated inhibition of glutathione reductase activity, which has a vital role in protecting the structural and functional integrity of sperm plasma membrane.Results indicated beneficial effects of supplementation of Mito TEMPO and acetovanillone on sperm freezability and individual supplementation was as efficient as the combination group for sustaining post-thaw semen quality.

Purpose The study aims to use nanofluids as coolants for improving heat transfer peculiarities of plate heat exchangers (PHE). The experimental and numerical investigations are thoroughly performed using distilled water-based Al2O3, graphene nanoplatelet (GnP) and multi-walled carbon nanotubes (MWCNT) nanofluids. Design/methodology/approach The numerical simulation based on Single Phase Model (SPM) was performed on a realistic 3 D model of PHE having similar dimensions as of the actual plate. The standard k-epsilon turbulent model was used to solve the problem. The concentration and flow rate of nanofluids were ranging from 0.1 to 1 Vol.% and 1 to 5 lpm, respectively, at 30°C. Whereas, hot side fluid is distilled water at 2 lpm and 80°C. The heat transfer characteristics such as bulk cold outlet temperature, heat transfer rate (HTR), heat transfer coefficient (HTC), Nusselt number (Nu), pressure drop, pumping power, effectiveness and exergy loss were experimentally evaluated using nanofluids in a PHE. Findings The experimental results were then compared with the numerical model. The experimental results revealed maximum enhancement in an average heat transfer rate of 9.86, 14.86 and 17.27% using Al2O3, GnP and MWCNT nanofluids, respectively, at 1 Vol.%. The present computational fluid dynamics model accurately predicts HTR, and the results deviate Originality/value The study helps to visualise heat transfer and flow distribution in PHE using different nanofluids under different operating conditions.

Friction stir welding and processing are widely used for joining of aluminum alloys and composites and fabrication of aluminum matrix composites. However, the friction stirred plates possess different microstructural zones which create significant difference in local properties and heat treatment is required to establish uniformity. In this article, the state-of-the-art of heat treatment on FSWed/FSPed aluminum alloys is discussed. The effects of heat treatment time and temperature on microstructural appearances and mechanical properties are examined thoroughly. Special attention is provided on the change in the state of precipitates by different heat treatment processes. Also, the effects of different heat treatment techniques are compared. Finally, some ideas regarding direction of new research related to current topic are addressed.

Despite the high strength-to-weight ratio, the poor tribological behavior and sea water corrosion performance of aluminum alloy limit its engineering applications. In this investigation, an attempt is made to obtain good wear and corrosion resistance by fabricating MoS2 and CeO2 reinforced aluminum 7075 matrix hybrid composites through friction stir processing. The microstructural observation suggests intermetallic free uniformly distributed composites are formed. The specific wear and corrosion rates of the fabricated composites are analyzed. The reason behind variation of the responses is investigated. The processing conditions such as rotational speed, traverse speed, tilt angle and mixing ratio of reinforcement powder are optimized for low specific wear rate and low corrosion rate using Taguchi optimization method. The effects of the processing conditions on individual responses are also investigated. Gray relation approach is also adopted for optimizing the processing conditions while considering equal importance of both the output responses.

The extensive use of aluminum matrix composites as structural material urges it to possess good surface properties such as wear and corrosion resistance. To achieve that, mixture of MoS2 and CeO2 powder was reinforced in Al7075 alloy through friction stir processing with different processing speed and multi-pass approach. The microstructural image analysis by optical microscope and scanning electron microscope revealed reduction of matrix grain size and improvement of particle distribution for lower processing speed and multi-pass processing. The elemental analysis indicated well dispersion of reinforcement particles in matrix along with the presence of compounds of aluminum alloy. The microhardness and tensile strength were increased with reduction of processing speed and increase of number of pass. The friction coefficient and the wear loss were also low for composites produced with low processing speed and multi-pass. A combined abrasive and adhesive wear was observed in all the processed composites. With increase of processing speed and number of pass, the corrosion behavior of the composites in 3.5% NaCl solution deteriorated. The composite produced with 30 mm/min and 2 pass exhibited best particle distribution, microhardness and wear resistance. However, the composite fabricated with 30 mm/min and 1 pass yielded best corrosion resistance.

Fish-associated microbiota are an integral part to the health of the host fish. The ongoing climate changes including global warming of water may disrupt the composition and diversity of host-microbiota, and subsequently, destabilize the fish homeostasis. Since the knowledge on temperature-sensitive marine fish and environmental bacteria is scarce, we investigated the effects of rearing temperatures on community structure, diversity and assembly process of bacteria on chum salmon (Oncorhynchus keta), which is a temperate salmon species found in the Pacific. Over the course of two weeks, laboratory-raised chum salmon were exposed to three temperatures: high (18°C), low (8°C) and, control (13°C). Their feces, cutaneous mucus, and surrounding water were sampled for community structure analysis based on 16S rRNA gene amplicon sequencing. Temperature changes from the control level triggered significant dysbiosis in the fecal and skin mucus microbiota. In particular, Vibrio and Tenacibaculum sequence variants were highly abundant at high and low temperatures, respectively, and the opportunistic growth of these pathogenic species may impede host immunity. Two temperature-specific taxonomic microbial biomarkers, the class Betaproteobacteria and the genus Flavobacterium were identified at both high and low temperatures. An analysis of bacterial community assembly processes revealed that environmental selection significantly affected the gut microbial community assembly, while the assembly process of the skin microbiota was stochastic. Our study elucidated the potential crisis of fish health when the equilibrium of the cutaneous and intestinal microbiota was disrupted by temperature changes. Our data will be a valuable tool to better understand the effects of climate change, a very pressing and important challenge now and in the future, on the fish microbiota and its homeostasis.

A brake pad material has been developed with multiwall carbon nanotube (MWCNT) and Nickel sulfate (NiSO4) to increase the heat transfer rate and better manufacturability. The maximum hardness of brake pad sample is found at 15 Ton compacting load and 150 °C sintering temperature. The performance of developed brake pad is compared with conventional brake pads. Scanning Electron Microscope (SEM) with Energy Dispersive X-Ray (EDX), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), gas sorption analyser (GSA) and thermal property analyser (TPA) are used to measure the distribution of elements, compound analysis, porosity distribution and thermal properties analysis respectively. The wear particles (mass loss) are less in the developed brake pad. The results show that developed brake pad material is superior compared to market available brake pads. An artificial neural network (ANN) model has been developed to predict the mass loss and coefficient of friction (CoF). The input parameters of 300 rpm, 50 N load and 125 °C temperature are the near optimal parameters combination for minimum wear and maximum CoF as observed by the design of experiment (DOE). The ANN and DOE results are verified with experimental findings. An ANSYS model has also been developed to study the temperature variation with time. The model has also compared with experimental results and found the 1% error.

Despite recent advances in technique of spermatozoa cryopreservation, there are still ejaculates present that fail to meet strict quality standard; mainly due to detrimental effect of imbalance of free radicals. The omnipresence of dead/defective spermatozoa in ejaculates of eutherian species is a major source of excessive free radicals. Though sperm-selection techniques, as well as addition of antioxidants addressed the problem to a certain extent, the major source of free radicals in the semen remained, causing much damage. This study attempts to remove dead/damaged spermatozoa using negative fertility-marker. The effect is unraveled by Hypo-osmotic (HOS), and fluorescein-conjugated Pisum sativum agglutinin (FITC-PSA) assay, further confirmed by Ca

A thin composite coating of composition Mo-WC-Cu-Si was deposited on an aluminium-2014 workpiece with the aid of the electro-discharge coating (EDC) process. The adhesion strength of the deposited coating was investigated by a scratch test. Scratch tests were carried at progressive loading condition and successive critical loads were found out. It was notified that the coating deposited at higher current levels has better adhesion strength. The surface morphology of the scratch channel/track and coated surface were characterized by using a scanning electron microscope (SEM). Energy dispersive spectrum (EDS) and elemental mapping have been conducted on the top surface of the coated layer. Results revealed that the composite coating has deposited uniformly with sufficient adhesion strength..

The alumina, copper oxide and zinc oxide nanoparticles (40 nm) were used to prepare the distilled water based nanofluids. The particle weight concentration varies in the range of 0.02% to 2%. The thermal conductivities were measured in the range of 20 °C to 90 °C. The input data for the present artificial neural network (ANN) model were nanoparticle weight fraction and nanofluid temperature and the output data was thermal conductivity of the nanofluid. The ANN used one hidden layer and it was optimised by varying number of neurons. The statistical approach has been employed to find out the coefficients in the proposed correlation using ANN validated experimental results. The estimated data obtained by the ANN model is in good agreement with the experiments. The proposed theoretical correlation is able to find out thermal conductivity ratio of nanofluids in a wide range of particle concentrations and temperatures.

This paper deals with the development and performance of metal matrix composite for brake pad with NiSO4 as filler materials in terms of manufacturing ability and a good amount of porosity. Microstructure and surface roughness of the samples are analysed using scanning electron microscopy (SEM) and atomic force microscopy (AFM) respectively. Energy dispersive x-ray (EDX) and scanning transmission electron microscopy (STEM) are used to detect elemental distribution in the sample. X-ray diffraction (XRD) compound phase analysis is used to find the presence of compound in the brake pad samples. The analysis shows that brake pad compounds are present in original form. Thermal property analyser shows that thermal conductivity and thermal diffusivity of developed brake pad are more than market available brake pads. Sufficient amount of porosity is observed with gas sorption analyser (GSA) which is useful for conductive and convective heat transfer and preventing the overheating of brake pad system. The design of experiment and experimental analysis leads to the conclusion of near optimum parameter combination for maximum coefficient of friction and minimum wear rate. This paper reveals that the developed brake pad is better than selected market available composite brake pads on basis of hardness, thermal property, porosity distribution, and tribological performance analysis. The developed brake pad may be one of the good options for the commercially use in near future.

The performance of an abrasive water jet machining (AWJM) process is mainly dependent on the jet diameter, which is prone to change with time due to the nozzle wear. The present study is aimed to monitor the nozzle wear during operation using vibrational spectrum. Experiments are conducted with four focusing nozzles of different diameters under same parameters considering water and water-abrasive mixture as the jet. The obtained vibration spectrum through an accelerometer and data acquisition system are analyzed by Suprathreshold Stochastic Resonance (SSR) technique using MATLAB. The results obtained shows that SSR technique is easy to implement and gives a better performance in monitoring and analyzing the wear severity.

The present work concentrate on the improvement in physico-chemical, and tribological properties of used engine oil using graphene nanoparticles. The used engine oil (15W40) has been collected from heavy earth moving machines (HEMM) of coal mines. The graphene nanoparticles have been used for the preparation of nanolubricants and the properties are compared with unused oil. Kinematic viscosity, viscosity index (VI) and density have been measured to examine the physico-chemical properties of nanolubricants and observe the improvements. The stable chemical structure of nanolubricants has been found with Fourier transform infrared spectroscopy (FTIR). The performance of nanolubricant has been found by measuring wear and friction coefficient between grey cast iron contacts and observed the significant reduction in wear and friction compared to used oil. The same has been validated by measuring the wear scar with the help of optical microscopy and electron dispersive X-ray spectroscopy. The life of the used oil has been enhanced with the addition of nanoparticles.

Degradation of a material due to the chemical/electrochemical and/or frictional interaction with the surroundings initiates at the surface because of the external stresses and frequent environmental attacks. The surface properties like hardness, wear resistance and corrosion resistance can be improved by means of composite coating. Recently Nickel based composite coating has found a new horizon because of excellent wear and corrosion resistance and high hardness. In this article, the Ni based metal matrix composite coating by various techniques are reviewed. Composition, process parameters, subsequent mechanical properties as well as microstructures and their effects are briefly tailored. Finally, new directions for future work on this technology are suggested.

Recent researchers widely used nanoparticle additives for improving thermal and rheological properties of machine lubricant. In present study the effect of Al2O3 and CeO2 nanoparticles on transmission oil (SAE30), hydraulic oil (HYDREX100) and gear oil (EP90) of heavy earth moving machinery is investigated. Nano-lubricant samples are prepared in 0.01–4% nanoparticle volume fraction range. Four machine learning techniques namely decision tree (DT), random forest (RF), generalized linear models and neural network (NN) have been used to predict the kinematic viscosity for Al2O3 and CeO2 nanolubricants. Further, multi-criteria decision-making technique named technique for order of preference by similarity to ideal solution have been used to find the best predictive method in each category of the nanolubricants. DT, RF and NN methods are found to be most accurate in kinematic viscosity prediction of transmission oil (R2 = 0.861), hydraulic oil (R2 = 0.971) and gear oil (R2 = 0.973), respectively.

Analysis of wear debris, vibration and temperature of journal bearing has been integrated to increase the accuracy in fault diagnosis of a hydropower plant. Samples of used lubricating oil, vibration data and bearing temperature at different intervals were collected. Wear particles and acceleration caused by vibration were analysed for the fault detections. An abnormal increase in the temperature and vibrational energy was observed after 200 days of continuous operations. In the last sample, an abnormal increase in aspect ratio of the wear particles was also observed. Scratches and wiping mark were found over the surface of bearing block and side thrust pad. This confirmed the fault of machine by the analysis of condition monitoring data. Further rectification was done by the replacement of bearing block.

Buffalo spermatozoa are vulnerable to cryo-injuries due to inherent deficiency of endogenous antioxidants, high polyunsaturated fatty acids (PUFA) content in plasma membrane and low cholesterol/phospholipid (C/P) ratio. Humanin is a potent cytoprotective agent that protects the cells against oxidative stress and apoptosis. The present study was designed to establish the presence of Humanin in buffalo and effect of Humanin supplementation on freezability of buffalo spermatozoa. Indirect immunofluorescence test revealed presence of Humanin in ejaculated and epididymal spermatozoa, and, elongated spermatids and interstitial space in the testicular tissue section. Humanin levels in seminal plasma were significantly and positively correlated with sperm concentration and individual progressive motility (IPM) in good (n = 22; IPM70%) and poor (n = 10; IPM50%) quality ejaculates. For supplementation studies, a total of 24 ejaculates (IPM ≥70%) were collected and each ejaculate was then divided into four aliquots. First aliquot was diluted with egg yolk-tris-glycerol (EYTG) extender without Humanin and served as control group (Group I). Rest three aliquots were diluted with extender containing 2 (Group II), 5 (Group III) and 10 μM Humanin (Group IV), respectively. Semen was cryopreserved using standard protocol and evaluated at pre-freeze for lipid peroxidation (LPO) and post-thaw stages for spermatozoa kinematics, LPO, mitochondrial membrane potential (MMP), capacitation, apoptotic status and DNA integrity. The treatment group that showed best results (5 μM) was compared with control group for in vitro fertility assessment by homologous zona binding assay. The LPO levels were lower (p 0.05) in 5 and 10 μM Humanin supplemented group. The MMP and DNA integrity were higher (p 0.05) in 5 μM group than other groups. F-pattern was higher (p 0.05) and B-pattern was lower (p 0.05) in 5 and 10 μM Humanin supplemented groups. Lower apoptotic and higher viable spermatozoa (p 0.05) were observed in 5 μM Humanin group. The mean number of spermatozoa bound to zona pellucida was higher (p 0.05) in 5 μM Humanin treated group than the control group. The study established the presence of Humanin in buffalo spermatozoa and seminal plasma for very first time and concluded that Humanin supplementation at 5 μM concentration improves the freezability and in vitro fertility of buffalo spermatozoa.

One of the most alternative for conventional fossil fuels, with any harmful effect like emission of greenhouse gases, global warming etc. is solar power energy system (SPESs). Solar power energy system has capability to convert solar energy in to heat energy and top most useable energy mode electricity. Due to presence of good thermo physical properties of different nanoparticles and nanofluids are better option to enhancing the performance of SPESs on thermal ground. This review article deals with the study of latest development in field of solar energy power system like different solar collectors, solar based water heater, solar based geothermal power system, solar water desalination, solar photovoltaic and solar thermal system based of nanoparticle and nanofluids.

The Cu–SS welded structures are widely used in nuclear and power generation industries. Various solid state and fusion welding techniques have been experimented for welding Cu–SS with resultant phenomena of low joining strength in solid state and generation of crack in fusion. Of late application of induction heating as a joining technique is gaining momentum in view of its low maintenance, high production rate and cost effectiveness. In consideration of the above facts, in this study, induction heating for welding Cu–SS is experimented in ambient condition under varied settings of load and current. Although few micro-cracks were observed in SEM images, successful joining between copper and stainless steel was achieved. Some compounds like FeCu4, Cr3Fe, Cu(Fe2O4) and CrO were detected by XRD near the weld interface. The microhardness increased near the interface in comparison to the base metals. The interface microhardness was increased with current and load. Similarly, the tensile strength was also increased for higher values of process parameters. Highest strength of 220 MPa was obtained at 2 kg load and 650 A current. Failure of welded joint under tension took place by ductile–brittle fracture mode.

Wear of a brake pad emits airborne particles and is a major environmental issue. This review paper deals with the analysis of different brake pad composite materials and their wear phenomenon. The volume fraction and size distribution of non-asbestos organic airborne particles emitted from the brake pad material with time, load and speed have also been discussed under different braking conditions. The airborne particles are measured by different aerosol instruments. TSI P-Trak, GRIMM aerosol spectrometer and scanning mobility particle sizer were used by different researchers for measuring ultrafine particles, micron-sized particles and aerodynamic nanoparticles, respectively. This paper shows that the wear particles emitted from the brake pad material vary in diameter between 10 nm and 10 μm under various loads and sliding velocities. These airborne particles such as coarse fine (diameters > 1 μm), fine (diameters between 100 nm and 1 μm) and ultrafine (diameters

This paper studies the effect of stochastic roughness on performance of a Rayleigh step bearing operating under Thermo-Elastohydrodynamic lubrication (Thermo-EHL). The shear flow factor along with pressure correction factor has been introduced in the generalized Reynolds equation to model the Gaussian roughness distribution on the surface of the bearing. Progressive Mesh Densification (PMD) as an efficient method for forward iteration has been applied to solve the mathematical model. The results show that directional orientation of the surface roughness significantly influence the performance of a bearing. Less pressure gets generated under surfaces with longitudinal roughness orientation compared to other orientations. Compared to longitudinal roughness orientation, transverse orientation generates more load capacity and provide less friction coefficient under Thermo-EHL.

Gear oil of heavy mining machineries are designed to provide anti-wear and anti-friction protection under extreme load condition. In present study thermophysical and tribological properties of industrial gear oil with nanoparticles additives (Al2O3 and SiO2) has been experimentally evaluated. Morphology of dry nanoparticles under FE-SEM shows that both nanoparticles are spherical. DLS test shows the presence of mild-agglomeration of nanoparticles in the dispersion. Density and viscosity of nanolubricants is tested with varying temperature and particle volume fraction. Measured viscosity results for Al2O3/gear oil nanolubricants follow the existing empirical model and new model has been proposed for SiO2/gear oil nanolubricants. Anti-friction and anti-wear properties of nanolubricants are tested on pin-on-disc test apparatus. FE-SEM and energy dispersive spectroscopy (EDS) analysis of wear scar (pin SS-304), evident the occurrence of ball bearing and surface polishing effects, which may be responsible for advanced tribological properties of the oil. Test results reveals that ball bearing have dominating effect in enhancement of tribological performance.

Purpose The probability distribution of major length and aspect ratio (major length/minor length) of wear debris collected from gear oil used in planetary gear drive were analysed and modelled. The paper aims to find an appropriate probability distribution model to forecast the kind of wear particles at different running hour of the machine. Design/methodology/approach Used gear oil of the planetary gear box of a slab caster was drained out and charged with a fresh oil of grade (EP-460). Six chronological oil samples were collected at different time interval between 480 and 1,992 h of machine running. The oil samples were filtered to separate wear particles, and microscopic study of wear debris was carried out at 100X magnification. Statistical modelling of wear debris distribution was done using Weibull and exponential probability distribution model. A comparison was studied among actual, Weibull and exponential probability distribution of major length and aspect ratio of wear particles. Findings Distribution of major length of wear particle was found to be closer to the exponential probability density function, whereas Weibull probability density function fitted better to distribution of aspect ratio of wear particle. Originality/value The potential of the developed model can be used to analyse the distribution of major length and aspect ratio of wear debris present in planetary gear box of slab caster machine.

Aluminium alloys, a structural material owing to the great specific strength, are often subjected to extensive wear and corrosive environment. Considering the situation, in this article, a hybrid composite was made by integrating MoS2 and CeO2 powder in Al7075 alloy by friction stir processing. The SEM image of the microstructure of the composite reveals well dispersion of the powder particles in aluminium matrix. During sliding contact against WC ball, a significant decrease in friction coefficient of the composite is observed due to the presence of lubricating MoS2 powder. The SEM micrographs of the worn surfaces indicate that the oxidation and severe adhesive type of wear in aluminium are changed to a combination of abrasion and adhesion type of wear in the composite. The specific wear loss of around 8 × 10−4 mm3/N-m of the aluminium alloy is reduced to nearly 4 × 10−4 mm3/N-m by incorporating micro-reinforcements. In a solution of 3.5% NaCl, the corrosion current density is drastically reduced to 8.18 × 10−7 A/cm2 from 2 × 10−6 A/cm2 of unreinforced alloy. Also, the corrosion potential is increased from −863.962 to −672.192 mV due to the addition of hybrid reinforcement. Moreover, the rapid corrosion of aluminium alloy is reduced, and secondary passivation due to the presence of CeO2 is observed. Therefore, it is evident that the wear resistance and corrosion resistance of the Al7075 alloy are improved by the addition of MoS2 and CeO2 powder.

This work aims to study thermo-physical properties, including thermal conductivity, viscosity, viscosity index, and rheology of vegetable oil-based nano-lubricant. Synthesis of nano-lubricant was done using vegetable seed oil (castor oil) and copper oxide (CuO) nano-particles using a magnetic stirrer and probe-type sonicator for breaking agglomerate. The thermal conductivity of samples was measured using transient hot-wire liquid thermal conductivity meter, and the effect of nano-particles was analyzed. Viscosity and viscosity index (VI) of the nano-lubricants thus prepared have been analyzed by Stabinger viscometer. The variation of viscosity of nano-lubricant with the shear rate was reported using an advanced air bearing rheometric system. The viscosity variation with respect to shear rate showed a decreasing trend, whereas the viscosity variation with respect to concentration showed an increasing trend. The results show that it is possible to increase the stability of samples in terms of viscosity variation with temperature and shear rate using nano-particles, hence makes it suitable for lubricant applications.

The perovskite solar cells (PSCs) have emerged as an established technology during the last decade, with the record efficiency of such solar cells having increased from 3.8 % to 25.5 %. Recently, flexible perovskite solar cells (fPSCs) have received much attention from the academic and the industrial communities, owing to their potential for various niche applications, including portable electronics, wearable power sources, electronic textiles, and large-scale industrial roofing. fPSCs are lightweight, bendable, and suitable for roll-to-roll industrial production and can be integrated easily over any surface. This Review discusses the recent development of materials for fPSCs based on various flexible substrates, including plastic, metal, and other flexible substrates, as well as fiber-shaped perovskite solar cells, with a focus on the device structure, material selection for each layer, mechanical flexibility and the environmental stability of the fPSC devices. Finally, future applications and the outlook for fPSCs are also discussed.

The study explores the affectability of oxygenated fuel on the performances and exhaust emissions of adulterated Diesel fueled engine. Diesel adulteration decreases brake thermal efficiency (Bth), brake specific energy consumption (BSEC), unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions with significant reduction in NOX emissions. Ethanol blending improves the engine exhaust emissions without altering performance parameters of adulterated Diesel. In perspective of the experimental data, multi parametric artificial intelligence (AI) based gene expression programming (GEP) models have been developed for mapping the input (engine load, Kerosene share and Ethanol share) and output (Bth, BSEC, NOX, UHC and CO) relationship under Diesosenol platforms. The model predicted output has been validated with experimentally measured data and some statistical measures. The predicted model matched the experimental data with very lower mean square error (0.00002-0.00031). The statistical results such as correlation coefficient (0.99910-0.99995), absolute fraction of variance (0.99821-0.99989), Nash–Sutcliffe coefficient of efficiency (0.992-0.99974) and Kling–Gupta efficiency (0.98091-0.99736) obtained from the GEP model, along with mean absolute percentage error, mean squared relative error and prediction model uncertainty betokened itself as a real time robust machine identical tool under various Diesosenol stages. In addition, Pearson’s chi-square test or goodness of fit measurement elevates the GEP model prediction quality to a higher level.

Wear debris size distribution in lubricated system closely related to lubricant condition and wear process. In this work, a model has been developed to predict the wear severity with operation time. The used oil samples were collected from Heavy Earth Moving Machines (HEMM) (Model No: BEML BH50M – dumper) employed in open cast mining (Dhanbad, India). Ferrography was used for the isolation as well as capturing image of wear debris from the collected samples. The captured images of wear debris were then processed for the generation of particle distribution using ImageJ software. It has been observed that most of the wear particles are found in 1–25 µm size range. The particle distribution over time has been studied using Weibull distribution model. Based on the statistical modelling of wear particles distribution with time of operation, results show that the percentage of larger particle (>25 µm) increase with time.

Aluminum matrix composites are widely used in aerospace, automotive industry and defense sector owing to its excellent weight-to-strength ratio. Friction stir processing has emerged as an excellent technique to produce particle reinforced as well as fiber reinforced aluminum matrix composites. This article is a state of the art of aluminum matrix composite fabrication by friction stir processing route. The fabrication procedure has been discussed with carefully mentioning the parameters associated with the process. Microstructures and consequent mechanical properties of the composites have been evaluated. Particular attention is given on the microstructural modification and strengthening mechanism. Also the wear and corrosion behavior of the composites has been discussed thoroughly. Finally, the article has been concluded with some suggestions toward future work.

A numerical simulation of rough slider bearing under thin-film lubrication using variable mesh density has been carried out. The current investigation deals with the effect of deterministic surface roughness patterns, such as triangular, sawtooth, square and sinusoidal roughness patterns and temperature on pressure and film thickness distribution. The nature and shape of roughness and temperature play a significant role in pressure generation, which in turn influences load capacity and frictional coefficient. It has been observed that variable mesh density takes around 25% less number of iterations compared to fixed mesh density. Among all roughness patterns, square roughness dominates the generated pressure. Elastic deformation of greater than 50 nm in bounding surfaces has been found to influence the film formation. Small pressure generated under piezoviscous elastic and thermo-piezoviscous elastic conditions was deficient in causing squeezing effect on lubricant, which suggests that bearing is operating under isoviscous elastic and thermo-viscous elastic conditions instead of piezoviscous elastic and thermo-piezoviscous elastic. Insensitivity in load capacity was observed for a smaller value of film thickness.

In the present study, Induction welding was carried out to achieve the joining between dissimilar metals such as mild steel (AISI 1015) and copper (Cu) in open atmosphere with different loads and different current settings. Microstructural evaluation of the welded joints was done by optical microscope and scanning electron microscope (SEM). The study showed that Cu was well bonded with mild steel (MS) without any crack near diffusion line. The X-Ray Diffraction (XRD) analysis was carried out and it revealed the presence of FeCu4 and Cu(Fe2O4) along with Cu and Fe. Joint quality was examined by measuring ultimate tensile strength (UTS) and microhardness. The UTS of the welded specimens was found to be increasing with the increase of load and current. The maximum UTS was obtained for specimen welded at 650 A with 2.5 kg load applied during welding. Microhardness distribution of the welded specimens showed that microhardness at interface line was more than that of copper and less than that of mild steel. The maximum microhardness on the copper side was at the interface line and attained base metal microhardness 1 mm onward from the interface. However the microhardness on mild steel side increased nearly upto 6 mm from the interface line.