Search

Carbon-free nickel alloy maraging steel has high demand in manufacturing aerospace vehicles and hypersonic missiles. Due to the absence of carbon and the strengthening of intermetallic precipitates, maraging steel can attain high strength and toughness with ductility. This material has enormous weldability in both annealed and post-weld heat-treated (PWHT) conditions. During high-thickness sections, the heat flow rate and the number of passes were found to be redundant. The existence of reverted austenite (RA) has been identified because prolonged aging also has an impact on the mechanical characteristics of the weldment. The present research demonstrates the characterization of plasma arc welded (PAW) maraging steel MDN 250 in welded and PWHT conditions. The weldments were subjected to three types of heat treatment, namely, (i) Subsequent Aging (TA), (ii) Solution treating + Subsequent Aging (STA), and (iii) Homogenizing + Solution treating + Subsequent Aging (HTA). This study also emphasizes the importance of precipitates and RA in affecting the strength and toughness of welded joints. The HTA treatment solely helps to eliminate the RA from the weldment. The microstructural study depicts the formation of reverted austenite in the TA condition. The reverted austenite has not been found in the microstructure under HTA conditions. The EBSD (Electron backscatter diffraction) analysis has resulted that the RA has been eliminated. The EDS (Electron Dispersive Spectroscopy) analysis shows that segregation of the enriched alloys has been effectively lowered in HTA condition. Compared to the other weldments’ mechanical characterization, the HTA condition gives supremacy results. The average ultimate tensile strength of 1830 MPa has been achieved in HTA condition, with a yield strength of 1809 MPa. The average fracture toughness results of 88.3 MPa√ m was obtained in HTA condition. The work display of PAW (Plasma Arc Welding) is capable of meeting all of the requirements for welding maraging steel in high-thickness sections.

In this research, dissimilar welding of the nickel-based superalloy Inconel 59 and austenitic stainless steel AISI 904L steel was successfully done with double-pulsed gas metal arc welding (DP-GMAW) using the filler ERNiCrMo-13. Macroscopic analysis showed a defect-free weld with an aspect ratio of 2.4, attributed to the efficient heat delivery (0.642 kJ/mm) in DP-GMAW. The microstructure of the weld joint was examined through both optical microscopy and scanning electron microscopy. Examination of the microstructure of the weld interface exposed grain coarsening near the heat-affected zone on the AISI 904L side. In contrast, the weld fusion zone contained fine equiaxed dendrites. Microsegregation and alloying element migration across the entire weld area were assessed through energy dispersive X-ray spectroscopy point analysis and line mapping, revealing controlled microsegregation across the region. X-ray diffraction (XRD) analysis was used to ascertain the average grain size (38.41 nm) and secondary phase composition. The XRD-cosα method was used to assess the residual stress of the weld joint, revealing tensile residual stress in the weld zone and compressive residual stress in other regions. Tensile, Charpy impact, and Vickers hardness tests were conducted in the study to evaluate the strength, toughness, and hardness of a dissimilar weld. The impact of two cryogenic treatments, namely shallow and deep, on tensile and toughness characteristics was investigated in this study. The cryogenic treatments significantly enhanced the mechanical properties of weld samples compared to their as-welded condition, leading to an 11.5% increase in tensile strength and a 10% improvement in toughness.

•Zr2NiZ (Z = Al, Ga,In) Heusler alloys exhibit half metallic ferromagnetism.•Optical properties are analyzed for the first time.•All these alloys exhibit 100 % spin polarization.•Total magnetic moment obeys Slater–Pauling rule.

Continuous monitoring of electrocardiogram (ECG) signal is made feasible with the progress in wearable technologies. The ECG signals are acquired and analyzed for health monitoring and diagnosis of cardiovascular diseases. However, ECG signals contaminated with various noises during acquisition must be screened to reduce false alarms during unsupervised health monitoring. Only clean signals should be analyzed for disease detection. We propose a robust and lightweight convolutional neural network (CNN) with an appropriate activation function, optimal number of convolution layers (CLs), and dense layers (DLs) for real-time and automatic ECG signal quality assessment (ECG-SQA) for an energy-constrained wearable health monitoring device with limited computing resources. The CNNs are trained and tested with standard ECG databases, which classify ECG signals as noisy and clean. The proposed optimal CNN for ECG-SQA has four CLs, five DLs, and an exponential linear unit (ELU) activation function. The optimal CNN for ECG-SQA has a sensitivity (SE) of 92.88%, 82.09%, and 99.64%, and specificity (SP) of 75%, 75.3%, and 73.97% for unseen databases of PhysioNet/Computing in Cardiology Challenge 2011, PhysioNet/Computing in Cardiology Challenge 2017, and St. Petersburg Institute of Cardiological Technics (INCART) 12-lead arrhythmia database, respectively. The proposed CNN has a model size of 5633 kB, testing time of 121.00 ± 39.77 ms, and energy consumption of 1851.3 ± 608.48 mJ for quality assessment of 5 s ECG signal when implemented on Raspberry Pi as a real-time computing platform.

By considering limited resource-constraints of medical devices and advanced deep learning networks, in this paper, we explore a lightweight convolutional neural network (CNN) based AFibri event detector by finding suitable hyperparameters and activation function with best trade-off between the detection accuracy and model size (or computational time). This study presents extensive evaluation results of CNN-AFibri event detection methods that are obtained for different combination of model parameters: number of convolutional layers (CLs of 3, 4, and 5), number of filters (8, 16, 32, 64 and 128), activation functions (including the rectified linear unit (ReLU), leakyReLU (LReLU), exponential linear unit (ELU)), and kernel sizes ( $3 \times 1 $ , $ 4 \times 1$ ). In addition to different CNN-AFibri models, we validate their performances under different ECG segment duration of 5, 10 and 30 seconds. On the standard databases and unseen databases, the CNN-AFibri model with the CLs of 5, ELU function and kernel size of $ 4 \times 1$ had a highest accuracy of 99.97% (specificity of 99.98% and sensitivity of 99.95%) for 5 second ECG segments as compared to the performances of 54 CNN-AFibri models reported in this paper and other existing deep learning based methods on the same validation databases. Real-time implementation of the best CNN based method with a model size of 3.14 Megabyte is demonstrated using the Raspberry Pi computing platform with Broadcom BCM2711, 1.5 GHz Cortex-A72 quad-core CPU with 8 GB RAM. Results demonstrated that the average processing times are less than 3 ms and 11 ms for processing 5 s and 30 s ECG segments, respectively with an accuracy reduction of less than 1% as compared to the same model tested on the personal computer with Intel(R) Xeon(R) W-2133 3.60 GHz Processor with 6 core and 128 GB RAM.

The global impact on climate change switches to the use of renewable energy. Nowadays, the concentrated solar power (CSP) power plant received more attention in the researcher’s interest. The major problem associated with the CSP plant is the hot corrosion in the container materials exposed under phase change material (PCM). In the present study, Inconel 617 and 625 were used as container materials and Na2SO4(50 Wt.%) +Diatomite (50 Wt.%) as PCM. The PCM based environmental assisted hot corrosion studies were conducted on container materials at 900°C for 40, 80, and 120 h duration. Differential scanning calorimetry (DSC) results confirmed the selected PCM melting temperature. The thermogravimetric analysis (TGA) is performed to determine the mass loss of the PCM. Fourier transform infrared (FT-IR) analysis confirmed the chemical compatibility between Na2SO4and diatomite. After hot corrosion at 120 h for 900°C, the weight change values are 3.1 and 2.6 mg/cm2for Inconel 617 and Inconel 625. In addition, the X-Ray Diffraction (XRD) and Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) analysis were carried out to evaluate the hot corrosion behavior. The result indicates that the formation of NiO, Cr2O3, and SiO2provides better resistance to corrosion in both container materials. Overall, Inconel 625 shows good corrosion resistance compared to Inconel 617 in a PCM environment.

In the present era of the medical field, the mortality rate of the infant increased by 1/3 percentage in a year. Even though we have modernized and have great expertise in the medical domain, we failed to control the infantile mortality rate. So continuous monitoring of the fetus during pregnancy is important. If there is any complication in the growth of the fetus, then the patient is put into the appropriate examination and medication proposed by the physician. In this paper, we propose methods to control the infant mortality rate in the early stage of pregnancy. Fetal heart rate of 2126 patients was collected and developed as datasets. Then with these datasets, we developed machine learning classifier models to classify the normal, suspect, and pathologic cases using the Decision tree, Naive Bayes, Random forest, and K-nearest neighbors. We divided the datasets into training dataset and testing dataset. Then the base classifier model was created using training datasets, and then the same models were verified by appending the test datasets. We improved the techniques and efficacy of the base classifiers by ensemble methods such as bagging and boosting. Finally, the datasets were classified as normal, suspect, and pathological cases with an improved accuracy of 96.617% with the help of the random forest classifier.

Vegetable oil becomes a viable alternative to mineral or synthetic oils due to its biodegradable nature. In this work, one such vegetable-based non-edible oil (kapok oil) is blended with a mineral-based oil (SAE20W40) at 15 and 30% ratio (by volume), and its changes in thermal, tribological, and corrosive properties were evaluated. Four-ball tribometer is utilized to assess its dynamic friction coefficient and the wear scar diameter of the worn out area on the ball. Biodegradability and toxicity test of kapok oil were examined and compared with the palm and mineral oil through bacterial growth and brine shrimp assay methods, respectively. The results showed that the dynamic friction coefficient and specific wear rate of the blended oil were lesser than the mineral oil. The mineral oil produced a higher roughness average (Ra) value than that of the blended oil. Kapok oil shows an adequate tribological properties (anti-friction and anti-wear) in contrast to the other vegetable oils. Overall, kapok oil had a high biodegradability nature and lower toxicity than the mineral oil.

Metal additive manufacturing (AM) has matured and grown from its infancy in the research stage to the fabrication of new and advanced components for its supreme applications. AM is a lead for the advanced manufacturing processes with an increased and advanced potential to revolutionize the manufacturing domain. It could exhibit a progressive change in the project and design paradigms. In the past decade, the use of metal AM process in the aerospace industry to build, repair various components for military applications and several outer space vehicle fabrications have occupied higher potential among various other manufacturing industries. In addition to it, many studies have made it a more versatile, common, and safer technology for the design and fabrication of components with the introduction of novel processes, materials, technologies, cost efficiency, and process design. In the present review article, the use of advanced aluminum alloys in the AM of fuselage, horizontal stabilizer, and high and low wings has gained increased advantages in the aerospace industry. Various components of wings and fuselage with its merits and demerits in AM processing are discussed. The outstanding issues in AM process and steps to overcome with post-processing techniques are elaborated. Finally, the future scope and research directions of the AM process involved in the fabrication of selected components are discussed.

In this work, an accurate estimation of the amplitudes and frequencies of the flicker components has been proposed using dynamic mode decomposition (DMD). The proposed method consists of Hilbert transform for envelope extraction, DMD for spectral analysis, and finally, the assessment of flicker severity index ( $\Delta {V_{10}}$ ) based on the eye-brain model. The DMD method constructs a shifted-stack matrix of the voltage signal, and thereby it is processed through singular value decomposition (SVD) for extracting the dominant signal parameters. To verify the effectiveness of the proposed technique, voltage flickers are considered with single flicker and multiple flicker components. It is also investigated in presence of sensitive conditions such as harmonic disturbance, power frequency deviation, noisy environment, phase jumps, and transients. The simulation results are compared with the existing techniques in terms of the relative errors of flicker parameters. Finally, a hardware prototype is developed for practical flicker measurement and the proposed algorithm has been implemented on the Raspberry pi board. The experimental results are presented and compared with simulation findings of the proposed technique to prove its applicability.

Selenium, an essential micronutrient with potent anticancer and antioxidant properties, the inorganic form of selenium is highly toxic, while organic and elemental nanoforms are more bioavailable and less toxic and have gained attention owing to their dietary and clinical relevance. This study aims to optimize conditions for the biosynthesis and production of elemental selenium nanoparticles for selenium supplements using marine microalgae, Nannochloropsis oceanicaCASA CC201. The 10 mM precursor solution treated with 1 % of the algal extract (10:1 ratio of precursor and algal extract, respectively) was shown to be the optimal concentration for synthesizing highly stable selenium nanoparticles with a size of 183 nm and a zeta potential of −38.5 mV. AFM and TEM analysis suggest that the spherical-shaped nanoparticles with smooth surfaces were polydispersely distributed. The nanoparticles are well characterized using various analytical and advanced techniques, including Raman spectroscopy and X-ray photoelectron spectroscopy. FT-IR analyses reveal the presence of microalgae proteins and peptides as stabilizing and fabricating agents of Se-NPs to further understand the mode of bioreduction. The synthesized elemental nanoform (Se0) has been validated for its biological functions, showing enhanced radical scavenging activity (74 % in a concentration-dependent manner). Subsequently, algal-mediated selenite reduction and nanoparticle synthesis is an eco-friendly, non-toxic, and sustainable method for the large-scale production of highly stable Se-NPs for niche applications as dietary and feed supplements.

Wheel rims are vital components critical to the safety of an automobile. Conventional wheel rims have utilized monolithic materials like aluminium and magnesium alloys in replacement to heavier steel rims. To reduce the weight of the formula car, lightweight composite wheel rims with higher stiffness are explored in the current work. Composite wheel rims are still in their nascent stage for commercial automotive applications, although they are commonly seen more in motorsports. The factors like complex design, high cost, and difficulty in fabrication are some of the demerits of composite wheel rims. Formula Manipal racing has been building race cars for Formula India events for over 13 years, on which aluminium wheel rims were standardly fitted. In the current work, the design and finite element analysis of carbon fibre wheels rims were undertaken to replace the aluminium wheel rims after a thorough consideration of other potential materials also. The modelling was carried out on CATIA3DX®, and finite element analysis was carried out using the ANSYS COMPOSITE PREP/POST (ACP)®module for laminate stackup and structural analysis tools for mechanical response. From the studies, the carbon fibre rims reduced the weight significantly by 42% while improving the factor of safety by 41% as compared to the current aluminium wheel rims while thermally outperforming magnesium and titanium alloys.

Dental decays are quite a recurring issue in today's busy life of people around the world; hence, its use is very standard practice. While dental implant development, materials, and procedures have significantly expanded and are predicted, it would further broaden throughout the coming decades. Much work is associated with the research to use new biomaterials, implant design, surface alteration, and functionalisation to make long-term care affordable and with better results. This article offers a short historical development of dental implants. It also gives information about the types of implants produced and the commonly used criteria throughout the implant design. Finally, this paper also discusses the various materials used in the coming future with some reasonably new additive manufacturing processes that have never been used before.

Herein, we delineate the one-pot preparation of nickel cobalt telluride nanorods (NiCoTe NRs) by the hydrothermal method using cetyltrimethylammonium bromide and ascorbic acid as reducing agents. The Ni0.7Co0.3Te NRs (NCT-1 NRs) were investigated with different characterization techniques, such as X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. Magnetic measurement shows the paramagnetic behavior of the prepared samples with the saturation magnetization. The NCT-1 NR-modified electrode is employed into the electrochemical hydrogen evolution reaction and hybrid supercapacitor applications. NCT-1 is demonstrated as a good electrocatalyst for the hydrogen evolution reaction at the onset potential of 244 mV versus reversible hydrogen electrode and delivered a high current density of 1 mA/cm2. NCT-1 displays a specific capacity of 433 C/g at 0.5 A/g current density and 100% capacity retention, even after 5000 cycles. Furthermore, a hybrid asymmetric supercapacitor device was fabricated on the basis of NCT-1 as a positive electrode and orange-peel-derived activated carbon (OPC-700) as a negative electrode. It delivered a high energy density of 43 Wh/kg and a power density of 905 W/kg with long cyclic stability of 91% after 25 000 cycles.

Breast cancer is a deadly disease and nowadays affects middle-aged women. Doctors use various methods to find out the presence of micro calcifications. In general, images of digital mammogram are used for cancer diagnosis. But the precision that determines the presence of cancer requires multiple restrictions. An improved medical decision support system for the classification of mammogram images using Unsupervised Test Vector Optimization (UTVO) based classifier is developed for health care and is presented in this work. The median filtering in the preprocessing stage removes the speckle, salt and pepper noises for mammogram image enhancement and the multilevel Tetrolet transformation based Matrix vectors are obtained for feature extraction. Multilevel Tetrolet transformation based features (MTF) are used for the selection of texture features. The UTVO classification approach proposed for identifying breast cancer exploits the potential and analyzes its performance after classification of benign and malignant cases. Finally, the UTVO classification system’s memory and computational time has been used to weigh the optimal weight and used to analyze the performance without compromise. The proposed system is expected to provide the best support for doctors to achieve maximum accuracy and improvement in health care.

Aluminium matrix composites are effective and qualified materials in the industrial domain. The presence of abrasive reinforcing particles and the conventional machining of these materials induces severe tool wear and poor surface finish. Wire-cut electro discharge machining is one of the best unconventional machining process for AMCs and it continues to rise at an accelerated rate. In this work, an attempt has been made to fabricate aluminium (A6061) reinforced zinc oxide particles by stir casting technique and determine the machinability behaviour of the sample. The process parameters regarded are pulse on time, voltage and wire feed rate and the measurable output parameters are metal removal rate and surface roughness. The experiments are carried through Taguchi's L9(33) orthogonal array as per design of experiment procedure. MOORA is one of the effective multi-objective optimisation methods to determine the best condition for machining on the basis of ratio analysis.

The effect of reinforcing natural fiber in the form of woven fabric on dynamic mechanical and thermogravimetric analysis was investigated. Further the influence of water molecule interaction on dynamic mechanical analysis of natural fiber composite were studied. Results revealed that basket type and intra-ply hybridized composites enhances the dynamic mechanical properties of the composites due to the enhancement in modulus by the reinforcement, whereas herringbone composites enhance the loss factor of the composites. It was noticed that, irrespective of the weaving architecture and intra-ply hybridization, composite samples immersed in the water for 45 days affects the storage and loss modulus of the composite and to enhance the loss factor. Thermogravimetric analysis carried out on composites revealed that, compared to weaving architecture, the presence of cellulose and hemicellulose in the fiber cell wall influences the thermal properties of the composites.

Nickelvac 23 is prone to hot fissuring due to elemental segregation in arc welding. The goal of the present research is to assess the possibility of mitigating the elemental segregation using arc welding processes with nickel-based filler wire. In this work, Nickelvac 23 weldments are made by gas tungsten arc welding techniques (Continuous and pulsed current modes) with ERNiCrMo-10 filler wire. The result of the macro evaluation depicts that defect-free welding with the proper fluid flow was accomplished in both weldments. The microscopical examination reveals the cellular and columnar structures in the weldment with CCGTAW and equiaxed structure in weldment with PCGTAW. Weldment with CCGTAW is detected with Mo segregation which forms the Mo23C6phases in the interdendritic region. Segregation of Si is noticed in all the weldments. Suppression of elemental segregation is noticed with PCGTAW while using ERNiCrMo-10 filler wire. XRD analysis shows the formation of interstitial compounds like MC, M12C, M23C6at the weldments. Tensile strength, hardness and toughness values are slightly improved in the PCGTAW as compared to CCGTAW due to the formation of interstitial compounds. Electron Backscatter Diffraction (EBSD) analysis confirmed the HAZ failure is due to the coarse grain structure. EBSD results also showed 36 % lesser grain sizes for the PCGTAW than the respective CCGTAW.

Alloy X is prone to liquation and solidification cracks in the weldments, because of the development of topologically close-packed precipitates such as σ, P, M6C, and M23C6carbides during arc welding methods. The present work examines the possibility of alleviating the segregation of Cr and Mo content to eliminate the development of topologically close-packed phases using a conventional arc welding technique. The welding of Alloy X has been achieved with ERNiCrMo-2 filler material by gas tungsten arc welding and pulsed current gas tungsten arc welding technique. The optical microscope shows the refined microstructure in pulsed current gas tungsten arc with respect to gas tungsten arc welding. The Mo-rich segregation was identified in gas tungsten arc weldment, and the same was absent in pulsed current gas tungsten arc. These segregations of Mo-rich content encourage the development of M3C and M6C secondary precipitates in gas tungsten arc welding. Pulsed current gas tungsten arc welding shows the existence of NiCrCoMo precipitate. The present work confirmed the absence of P, σ, and M23C6in both the weldments of Alloy X. The ultimate tensile strength, microhardness, and impact strength of pulsed current gas tungsten arc welding are increased by 3.39, 9.17, and 21.62%, respectively, with gas tungsten arc welding. The observed Mo-rich M3C and M6C secondary phases in the gas tungsten arc welding affect the tensile strength of the weldments.

In the past few decades, online games have become immensely popular among the younger generation thus leading to online game addiction. Previous researches acknowledge that mindfulness or present-focused awareness may reduce addiction. Moreover, addiction is found to have an impact on the propensity to respond to the situations in the environment in a way that is acceptable to all the people (emotional control). The present study attempts to study the influence of mindfulness and emotional control on game addiction. For this, 187 college students were selected through the Simple Random Sampling method. Personal Profile Sheet, The Online Game Addiction Scale, Mindful Attention Awareness Scale (MAAS) and The Emotional Control Questionnaire, with four dimensions of Rehearsal, Emotional Inhibition, Aggression Control and Benign control were used to collect the data. The study found a significant gender difference in the level of game addiction where boys being more addicted to online games than girls. Mindfulness shows a significant negative influence over Game Addiction. Among the four dimensions of emotional control, the two dimensions viz., rehearsal and benign control show mediation effect between mindfulness and game addiction. However, the mediating role of emotional inhibition and aggression control was not significantly demonstrative.

•Tool wear was observed during friction stir welding of NiTi alloy.•Tungsten inclusions have altered the composition of the weld center.•The weld has showed good thermomechanical properties.•The corrosion resistce of NiTi alloy has reduced after welding.

•The welding of Hastelloy X is studied for GTA and PCGTA techniques using filler material ERNiCrCoMo-1.•The hot cracking in the weldment of Hastelloy X is prevented by eliminating the Mo-rich M6C and Cr- rich M23C6carbide precipitates through PCGTA technique.

In the current study, alloy 80A weldments were produced through tungsten inert gas welding (TIGW) and pulsed current tungsten inert gas welding (PCTIGW) technique using 263 filler wire. Corrosion study was conducted on weldments in both air oxidation environment and molten salt environment under 50 cyclic condition at 900 °C. The results of thermogravimetric analysis showed that corrosion behaviour of weldments obeyed the parabolic rate law of oxidation. Higher weight gain was observed in TIGW under molten salt condition. Less weight was observed in PCTIGW under air oxidation condition. It is inferred that substrates subjected to molten salt environment showed higher weight gain than its respective substrates under air oxidation condition. The existence of Cr2O3, NiO and spinal oxide NiCr2O4offered good corrosion resistance to substrates. Thus, it was deduced that PCTIG weldments provided good corrosion resistance at high temperature than its respective TIG weldments.

•Site occupancies of Fe2−xCoxTiGe (x = 0, 0.5, 1, 1.5, 2) full Heusler alloys are studied.•The substitution of Co atom in Fe2TiGe for Fe, changes the semiconducting behavior to half metallic behavior.•Fe2TiGe alloy attains magnetism after the introduction of Co atom.•Half metallic to metallic phase transition is observed at high pressure.•All the studied full Heusler alloys (except Fe2TiGe) show 100% spin polarization at ambient conditions.

The present study investigates the type II low-temperature (600 °C) corrosion behavior of X22CrMoV12-1 substrate coated with NiCrAlY and 80Ni–20Cr powders through a detonation spray technique. Coated substrates and uncoated substrates were exposed to low-temperature corrosion test in both air oxidation environment and molten salt environment for 50 cycles at 600 °C. From the thermogravimetric analysis, it was seen that all the substrates trailed parabolic rate law. Higher weight gain resulted in the uncoated substrate under molten salt environment. NiCrAlY substrate showed lesser weight gain under air oxidation environment. It was also noted that lesser weight gain was observed in coated substrates (NiCrAlY and 80Ni20Cr) compared to the uncoated substrates. The presence of MnCr2O4, Ni3Al, NiO, Cr2O3, and Al2O3provided good hot corrosion resistance to coated substrates. Thus, it showed that NiCrAlY and 80Ni–20Cr coated X22CrMoV12-1 substrate delivered adequate resistance to corrosion at 600 °C.

This research work investigates the effect of laser shock peening (LSP) on commercially pure titanium grade 1 (CP Ti-1) weldment. The welding was done using gas tungsten arc welding (GTAW) with ERTi-2 filler wire. LSP was carried out on the cap surface of the weldment. The optical microstructure showed the Widmanstatten-type martensitic structure in the fusion zone (as-welded). The LSP fusion zone showed a refined microstructure compared to that of as-welded condition. Scanning electron microscope (SEM) of LSP weldment showed the indentation on the surface of the weld. This was a result of the surface ablation that occurred during LSP. X-ray diffraction analysis showed the absence of transformation of phases in the weldment. A reduction of 14.8% of crystalline size was observed in LSP weldment. A higher compressive residual stress was observed in LSP weldment than the as-welded condition. Tensile test showed the occurrence of failure in the base metal region in the case of LSP weldment, as against the failure in the case of as-welded condition in the fusion zone.

This research article examines the metallurgical and mechanical behavior of twenty-first-century nickel-based superalloy 686. The weld joints were produced with ERNiCrMo-4 and ERNiCrMo-14 filler wires by continuous current gas tungsten arc welding (GTAW) and pulsed current gas tungsten arc welding (PCGTAW) mode. Optical and scanning electron microscope (SEM) analyses were performed to evaluate the microstructure of welded joints. PCGTAW weldments showed refined microstructure, narrower weld bead and minimum heat-affected zone compared to GTAW. SEM analysis revealed the presence of secondary phases in the interdendritic regions of GTA and PCGTA weldments made of ERNiCrMo-4 and GTA ERNiCrMo-14 fillers. Energy-dispersive X-ray spectroscopy examination was also performed to assess the microsegregation of alloying elements in the weldments. The results proved nonexistence of microsegregation in the case of PCGTA weldments made by ERNiCrMo-14 filler. However, segregation of alloying element Mo was noticed in other weldments. Strength and toughness of the weld joints were evaluated by conducting tensile and Charpy impact tests. The refined microstructure with the absence of microsegregation obtained in the PCGTA welding made with ERNiCrMo-14 filler wire resulted in the higher strength and toughness than other weldments.

Here, we describe the successful hydrothermal synthesis of zinc cobalt sulfide (ZCS) and reduced graphene oxide/zinc cobalt sulfide (rZCS) nanoparticles (NPs). X-Ray diffraction (XRD), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (TEM) characterizations were used to test ZCS and rZCS NPs. Through the use of cyclic voltammetry (CV), galvanostatic charge and discharge (GCD), and electrochemical impedance (EIS), the electrochemical performance of the produced materials was examined. Electrochemical hydrogen evolution reactions and supercapacitor applications required the development of ZCS and rZCS electrodes. 10 mA cm−2is driven by rZCS electrodes at 132 mV HER overpotential. High specific capacitance of 891 F g−1at 1 A g−1current density and 99 % cyclic stability are displayed by the rZCS electrode even after 5000 cycles. The specific capacitance of (181 F g−1at 1 A g−1current density), capacitance retention of (92 % after 10,000 cycles at 1 A g−1, and energy and power density of (29 Wh kg−1and 2215 W kg−1), respectively, are recommended for asymmetric supercapacitors made from cells using rZCS and rGO. Given this, the produced electrodes material holds potential for use in energy storage technologies.

In the present study, the influence of microstructural changes on the mechanical and corrosion properties of the dissimilar weld between austenitic stainless steel (ASS 316L) and duplex stainless steel (DSS 2205) has been examined and reported. The weld joint was fabricated through the use of gas tungsten arc welding process with a nickel enhanced filler metal ER 2209. The microstructural changes observed in the fusion zone such as nucleation of delta ferrite (δ), austenite (γ) reformation, precipitation of intermetallic phases and the formation of coarser ferrite phases in the HAZ have been reported. Also, the mechanical properties of the weldment such as microhardness, impact toughness and tensile properties have been correlated with microstructural changes. Potentiodynamic polarization test results showed a better electrochemical behavior for ASS 316L than with the weldment and the parent metal of DSS 2205. The austenite phase was found to be electrochemically more stable than the ferrite phase in duplex microstructure. On the other hand, achievement of the stress corrosion cracking resistance by the weldment and the parent metal of DSS was found to be excellent, whereas ASS 316L ended with surface fissures.

Alloy 80 A is prone to hot cracking during conventional arc welding process. Microsegregation of alloying element Cr lead to the formation of M23C6carbide phase during solidification of fusion zone, and it contributes to hot cracking. The current study employs different welding techniques and filler wires to minimize the microsegregation. The weldments were fabricated by Gas Tungsten Arc Welding (GTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) techniques using filler wires 263 and ERNiCrMo-3. Scanning electron microscope (SEM) reveals the existence of secondary phase in the interdendritic region for all the weldments. Energy dispersive X-ray spectroscopy (EDS) analysis reports that PCGTAW eliminates microsegregation of Cr precipitate and suppress Nb and Mo precipitates better when compared to GTAW. X-ray Diffraction (XRD) analysis indicate the presence of M23C6Cr and Mo-rich carbide phase in GTA weldment of 263 filler wire. Whereas in PCGTAW, NiCrCoMo phase is observed. In both GTAW and PCGTAW of ERNiCrMo-3, the intermetallic phases Ni8Nb and Cr2Ti are observed. The tensile test was conducted to assess the strength and ductility of the weldments. The results of the PCGTAW weldments have improved compared to their respective GTAW weldments.

Electrocardiogram (ECG) signal quality assessment (SQA) plays a vital role in significantly improving the diagnostic accuracy and reliability of unsupervised ECG analysis systems. In practice, the ECG signal is often corrupted with different kinds of noises and artifacts. Therefore, numerous SQA methods were presented based on the ECG signal and/or noise features and the machine learning classifiers and/or heuristic decision rules. This paper presents an overview of current state-of-the-art SQA methods and highlights the practical limitations of the existing SQA methods. Based upon past and our studies, it is noticed that a lightweight ECG noise analysis framework is highly demanded for real-time detection, localization, and classification of single and combined ECG noises within the context of wearable ECG monitoring devices which are often resource constrained.

In this paper, the authors present an automated method for quality assessment of electrocardiogram (ECG) signal. Our proposed method not only detects and classifies the ECG noises but also localizes the ECG noises which can play a crucial role in extracting reliable clinical features for ECG analysis systems. The proposed method is based on three stages: Wavelet decomposition of ECG signal into sub-bands; simultaneous ECG signal and noise reconstruction; extraction of temporal features such as maximum absolute amplitude, zerocrossings, kurtosis and autocorrelation function for detection, localization and classification of ECG noises including flat line (FL), time-varying noise or pause (TVN), baseline wander (BW), abrupt change (AB), power line interference (PLI), muscle artifacts (MA) and additive white Gaussian noise (AWGN). The proposed method is tested and validated against manually annotated ECG signals corrupted with aforementioned noises taken from MIT-BIH arrhythmia database, Physionet challenge database, and real-time recorded ECG signals. Comparative detection and classification results depict the superior performance of the proposed method over state of art methods. Detection results show that our method can achieve an average sensitivity (Se), average specificity (Sp) and accuracy (A) of 99.61%, 98.51%, 99.49% respectively. Also, the method achieves a Se of 98.18%, and Sp of 94.97% for real-time recorded ECG signals. The method has an average timing error of 0.14s in localizing the noise segments. Further, classification results demonstrate that the proposed method achieves an average sensitivity (Se), average positive predictivity (PP) and classification accuracy (Ac) of 98.53%, 98.89%, 97.50% respectively.

Even though Nickel based superalloy (alloy 600) exhibits high corrosion resistance at elevated temperatures, the main limitation of this alloy is the formation of Cr-depleted zones in the grain boundary regions. In this regard, there is a constant demand for the reduction of Cr-depleted (sensitization) zones towards various applications. In order to achieve this, the present work is focussed on the fabrication of weld joints by Gas Tungsten Arc Welding (GTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) using the filler wires such as ERNiCr-3, ERNiCrMo-3, and ERNiCrMo-14 to avoid sensitization. The fabricated materials were analyzed by optical and scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). The macro examination of these welded materials clearly reveals the presence of defect-free weld joints. As per the results from the microstructural analysis, the rapid cooling was achieved in the pulsed current technique, and subsequently, the equiaxed dendrites were observed in the fusion zone. EDS analysis showed the presence of Nb-rich (MC) carbide phases near the joints fabricated by filler wires i.e.GTA ERNiCr-3 and ERNiCrMo-3 indicating the preferential formation of Nb-carbide over Cr-carbide. In a similar way, Mo-rich M23C6phases were observed near the joint fabricated by the filler wire, GTA ERNiCrMo-14. There was no microsegregation observed during the fabrication through the PCGTA welding technique.

In this paper, the state estimation problem is studied for the bidirectional associative memory (BAM) fuzzy cellular neural networks (FCNNs) with delays, where the delays include leakage and unbounded distributed delays. The problem addressed is to estimate the neuron states, through available output measurements, such that for all admissible leakage and unbounded distributed delays, the dynamics of the estimation error is globally asymptotically stable. A delay-dependent linear matrix inequality (LMI) criterion for the existence of the estimator is proposed by using the Lyapunov–Krasovskii functional method. In addition, the unknown gain matrix is determined by solving a delay-dependent LMI. Finally, numerical examples and simulations are provided to illustrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

The demand for lightweight structures made of sandwich panels is ever increasing in many Industrial sectors. Numerous research efforts have been taken by various researchers in this area in terms of weight and cost reduction. Sandwich panel is a composite structure and it is an excellent alternative material in place of weight reduction without sacrificing its strength and stiffness characteristics. The geometrical characteristics of honeycomb core sandwich panels as well as their physical and mechanical properties such as compressive strength, flexural stiffness, core shear moduli, shear strength and stiffness are analyzed. The sandwich panels are available in various shapes and sizes to the service requirement. The commercially available sandwich panels have different core materials such as foams, FRPs and metallic and non metallic materials. The structure of the core typically varies as truss type and honeycomb. The face sheets and the core materials are bonded using thermo-set resins.

The Mo-rich TCP phases P and μ are susceptible to hot cracking in the alloy C-276. These phases can be reduced by quashing the microsegregation of alloying element Mo in the weldment. The present study investigates the possibility of reducing the microsegregation by post weld heat treatment of the weldments. The joints were fabricated by pulsed current gas tungsten arc welding by employing different filler wires ERNiCrMo-3 and ERNiCrMo-4. The weld joints were characterized with respect to microstructure, Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), and tensile test. The optical microstructure revealed the fine equiaxed dendrites were observed in the fusion zone. EDS analysis revealed the presence of Mo-rich segregation in the subgrain boundary in the ERNiCrMo-3 and absence in the later. The results show that selection of temperature to dissolve Mo segregation is not sufficient in the case of ERNiCrMo-3. The tensile result shows the improved strength in both weldments compared to base metal.

The needs of the dissimilar weld joint between superalloy and stainless steel is increasing in many industries. Gas tungsten arc welding (GTAW) and shield metal arc welding (SMAW) are the most common methods used to fabricate the weld joints in the fabrication industry due to its high versatility in the fabrication of industrial components and parts. The present study investigated the metallurgical and mechanical properties of bimetallic joints fabricated between nickel-based superalloy Incoloy 800 and stainless steel AISI 316L. The weld joints were fabricated by using ERNiCrMo-3 filler wire. The micrograph of weld fusion zone revealed the austenitic microstructure with columnar dendrite and cellular structure in both weldments. SEM/EDS analysis witnessed the precipitation of Nb-rich phase in the weld fusion zone fabricated by SMAW process, and it was minimized in case of GTA welding technique. The strength and toughness of the weld joint fabricated by GTAW improved 14 and 25% respectively when compared to SMAW technique.

The structural stabilities of cobalt mononitride (CoN) and nickel mono-nitride (NiN) were investigated among the crystal structures, namely, NaCl (B1), CsCl (B2), and zinc blende (B3). It was found that the zinc blende (B3) phase was the most stable phase for both nitrides. A pressure-induced structural phase transition from B3 to B1 phase was predicted in these nitrides. The computed lattice parameter values were in agreement with the experimental values and other theoretical values. The electronic structures reveal that these nitrides are metallic at zero pressure. The computed elastic constants indicate that CoN and NiN are mechanically stable in the B1 and B3 phases. The variations of the elastic constants, bulk modulus, shear modulus, Poisson’s ratio, and elastic anisotropy factor with pressure were investigated. The Debye temperature θDvalues are reported for both the nitrides in their B1 and B3 phases. The high-pressure NaCl phase of both CoN and NiN were found to be ferromagnetic.

The present work investigates the microstructure and mechanical properties of alloy C-276 fabricated by continuous and pulsed current gas tungsten arc welding process and by employing ER2553 filler wire. Optical and scanning electron microscopic analyses were carried out to study the microstructures of weldments produced. Energy dispersive X-ray spectroscopy (EDS) was performed to investigate the formation of secondary phases in the weldments. The results disclosed that pulsed current gas tungsten arc welding showed refined microstructure compared to continuous current gas tungsten arc welding. SEM/EDS analysis revealed the segregation of Mo in the weld interface regions in both the welding techniques. The extent of microsegregation reduced the strength and toughness of the weld joint compared to the base metal. Bend test revealed cracks in the weld interface region in both the weldments.

Tellurium nanoparticles (Te Nps) were synthesized by wet chemical method and characterized by XRD, Raman, FESEM, TEM, XPS, UV–Vis and FL. The Nps were coated on graphite foil and Glassy carbon electrode to prepare the electrodes for supercapacitor and biosensor applications. The supercapacitor performance is evaluated in 2M KOH electrolyte by both Cyclic Voltammetry (CV) and galvanostatic charge-discharge method. From charge-discharge method, Te Nps show a specific capacitance of 586F/g at 2mA/cm2and 100F/g at 30mA/cm2as well as an excellent cycle life (100% after 1000cycles). In addition, the H2O2sensor performance of Te Nps modified glassy carbon electrode is checked by CV and Chronoamperometry (CA) in phosphate buffer solution (PBS). In the linear range of 0.67 to 8.04μM of hydrogen peroxide (H2O2), Te NPs show a high sensitivity of 0.83mAmM−1cm−2with a correlation coefficient of 0.995. The detection limit is 0.3μM with a response time less than 5s.

AbstractAllocation of security system is one of the challenging problems of decision makers to take decision about attacks by terrorists. To carry out this task is a complete set of security objectives. In this paper, applying a statistical method to measure the expected live loss for terrorist attacks by means of binomial distribution and allocate the security forces based on the expected live loss. The results are presented numerically as well as graphically.

AbstractArtificial Neural Network (ANN) provides an attractive alternative tool for researchers for agricultural forecasting. The Multi Layer Feed Forward Neural Net (MLFFNN) is one of the most widely used neural nets. Here, the MLFFNN architecture is examined and compared with time series models such as Autoregressive Integrated Moving Average (ARIMA) model for prediction of agricultural production. Both models were compared using visualization technique and statistical tests and the results were illustrated numerically and graphically.

Strontium hexagonal ferrite particles having single domain nature were prepared by initial ball milling followed by sintering. Effect of the synthesis method on structural, magnetic, and electrical properties were analyzed using various characterization techniques. XRD pattern reveals the formation of hexagonal phase SrFe12O19. XPS study indicates the presence of Fe3+in different crystallographic environments. SEM image suggests the size of particles in the range of single domain. VSM studies; M–Hloop illustrates the ferrimagnetic nature and the initial magnetization behavior demonstrates the typical behavior of single domain particles. Temperature‐dependent magnetization shows a Hopkinson peak before transition. Conductivity study shows two different conduction process with the activation energy values of 0.2 and 0.95 eV. The variation in the dielectric behavior with respect to frequency and temperature are explained using the grain‐grain boundary and polarization contributions. The hard ferrimagnetism and good dielectric response renders this material suitable for magneto‐electronic devices.

The present study aims to investigate the spatial and temporal variation of meteorological drought in the Parambikulam-Aliyar basin, Tamil Nadu using the Standardized Precipitation Index (SPI) as an indicator of drought severity. The basin was divided into 97 grid-cells of 5 × 5 km with each grid correspondence to approximately 1.03 % of total area. Monthly rainfall data for the period of 40 years (1972–2011) from 28 rain gauge stations in the basin was spatially interpolated and gridded monthly rainfall was created. Regional representative of SPI values calculated from mean areal rainfall were used to analyse the temporal variation of drought at multiple time scales. Spatial variation of drought was analysed based on highest drought severity derived from the monthly gridded SPI values. Frequency analyse was applied to assess the recurrence pattern of drought severity. The temporal analysis of SPI indicated that moderate, severe and extreme droughts are common in the basin and spatial analysis of drought severity identified the areas most frequently affected by drought. The results of this study can be used for developing drought preparedness plan and formulating mitigation strategies for sustainable water resource management within the basin.

Carbon - Carbon (CC) area unit extremely used as a neighborhood of various coming up with applications attributable to its weight lightweight property. Yet, this area unit got to oppose wear and acquire to be feeble for tribological applications. This marvel raises the need for Carbon - Carbon Matrix Composites (CCMCs) for elite tribological applications. For the foremost half, the fortifications area unit intercalary with the CC to structure CCMCs through fluid throwing system. The impact of fortifications in CCMCs specimens area unit tried to find the modification in mechanical and tribological properties. The mechanical properties like hardness and snap area unit tried. The wear and tear element enclosed within the modification of tribological property is focused on utilizing the minute photos. The implications of various fortifications in CCMCs area unit solid and therefore the unmatched support is distinguished for tribological applications

There is a need to move from system flexibility to process flexibility with advancements of research in the niche field of flexible systems management. This paper analyses how much Indian organisational flexibility is aligned with employee expectations, greater workforce utilization and avoiding process failures amidst the process of globalization trends. The paper attempts to reduce risks and add up values in the business process flow. It maps key flexibility functions and expectations within the vast head of organisational flexibility. The paper works to find empirical links between employee reactions to Indian organisational flexibility and expanding business process optimization with globalization impacts and the responses towards organisational strategies. The paper also investigates on how exactly the dynamics of Indian organisational flexibility contributes to the economy and social stand points of a fast growing nation. Flexibility as a process is studied with challenges, positive trends, organizational abilities and reactions fitting well with global business environment.

AbstractThe Research works on Key Management Schemes in Mobile Ad-Hoc Networks (MANETs) are attracting more and more attention to Researchers. Proving secured communication in MANET is extremely challenging one as it is dynamic in nature and the lack of centralized management. To address these issues, several researchers have proposed Key Management Schemes. In this work, we have identified and thoroughly studied three popular Key Management Schemes namely i. ID-based Multiple Secrets Key Management Scheme ii. RSA Certificate-Based Cryptography and iii. ID-Based Authenticated Group Key Agreement Protocol. We have proposed an efficient Genetic Model to optimize the performances of Key Management Schemes in terms of Key Initialization, Selecting Random Number Generator, Key Updation Timing, Packet Size, Computing Future Session Key and Session Group Key and forming Dynamic Clustering Group. The proposed Genetic Model was successfully implemented with VC++ and integrated with the above mentioned Key Management Schemes. From our experimental results, we revealed that the Genetic Model Based Key Management Schemes achieving higher security level as compared with ordinary Key Management Schemes, particularly the Genetic ID-Based Authenticated Group Key Agreement Protocol outperforms all the other two identified Key management Schemes in terms of Mobility Robustness, Computational and Message Overhead, Strength of Security, Key Exchange Time, Power Consumption and Key Update Time.