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Heat transport of hybrid nanomaterial in an annulus with quadratic Boussinesq approximation
The convective heat transfer of hybrid nanoliquids within a concentric annulus has wide engineering applications such as chemical industries, solar collectors, gas turbines, heat exchangers, nuclear reactors, and electronic component cooling due to their high heat transport rate. Hence, in this study, the characteristics of the heat transport mechanism in an annulus filled with the Ag-MgO/H2O hybrid nanoliquid under the influence of quadratic thermal radiation and quadratic convection are analyzed. The non-uniform heat source/sink and induced magnetic field mechanisms are used to govern the basic equations concerning the transport of the composite nanoliquid. The dependency of the Nusselt number on the effective parameters (thermal radiation, nonlinear convection, and temperature-dependent heat source/sink parameter) is examined through sensitivity analyses based on the response surface methodology (RSM) and the face-centered central composite design (CCD). The heat transport of the composite nanoliquid for the space-related heat source/sink is observed to be higher than that for the temperature-related heat source/sink. The mechanisms of quadratic convection and quadratic thermal radiation are favorable for the momentum of the nanoliquid. The heat transport rate is more sensitive towards quadratic thermal radiation. 2021, Shanghai University and Springer-Verlag GmbH Germany, part of Springer Nature. -
Studies on Parametric Optimization of HVOF-Sprayed Cr2O3 Coatings on Al6061 Alloy
High-velocity oxy-fuel (HVOF) is a widely used thermal spray technique to obtain high density, high bond strength, and improved hardness coatings. In the present work, optimization of HVOF process parameters was carried out using the Taguchi method to minimize porosity and improve microhardness, and bond strength of Cr2O3 coatings. Based on the signal-to-noise ratio and analysis of variance, the significance of each process parameter and optimum parameter combination is obtained. Based on the signal-to-noise ratio, the most significant process parameter affecting porosity and microhardness was standoff distance, while for bond strength, it was powder feed rate. An optimal combination of process parameters for porosity, microhardness, and bond strength was obtained from S/N ratio analysis. For porosity, optimal parameters were standoff distance of 100rpm, powder feed rate of 30g/min, and gun speed of 250mm/s. The optimal process parameters for microhardness were standoff distance of 300rpm, powder feed rate of 50g/min, and gun speed of 200mm/s. Finally, for bond strength, the optimal process parameters were standoff distance of 300rpm, powder feed rate of 50g/min, and gun speed of 250mm/s. Statistical results for porosity, microhardness, and bond strength showed that the difference between the predicted R2 and adjusted R2 values were relatively minimal and close to the one highlighting the fitness of the regression model employed for analysis. Fracture analysis after bond strength test showed combined adhesion/cohesion type failure for the Cr2O3 coatings. 2021, The Indian Institute of Metals - IIM. -
Dynamic optimal network reconfiguration under photovoltaic generation and electric vehicle fleet load variability using self-adaptive butterfly optimization algorithm
Currently, electrical distribution networks (EDNs) have used modern technologies to operate and serve many types of consumers such as renewable energy, energy storage systems, electric vehicles, and demand response programs. Due to the variability and unpredictability of these technologies, all these technologies have brought various challenges to the operation and control of EDNs. In this case, in order to operate effectively, it is inevitable that effective power redistribution is required in the entire network. In this paper, a multi-objective based dynamic optimal network reconfiguration (DONR) problem is formulated using power loss and voltage deviation index considering the hourly variation of load, photovoltaic (PV) power, and electric vehicle (EV) fleet load in the network. This paper introduces recently introduced meta-heuristic butterfly optimization algorithm (BOA) and it's improve variant of self-adaptive method (SABOA) for solving the DONR problem. The simulation study of IEEE 33-bus EDN under different conditions has proved the effectiveness of DONR, and its adoptability for real-time applications. In addition, by comparing different performance indicators (such as mean, standard deviation, variance, and average calculation time) of 50 independently run simulations, the efficiency of SABOA can be evaluated compared with other heuristic methods (HMs). Comparative studies show that SABOA is better than PSO, TLBO, CSA and FPA in the frequent occurrence of global optimal values. 2021 Walter de Gruyter GmbH, Berlin/Boston 2021. -
Electron beam mediated synthesis of photoluminescent organosilicon nanoparticles in TX-100 micellar medium and their prospective applications
The inherent advantages of Silicon have made it as one of the most sought-after elements in the field of nanoscience and nanotechnology. Herein, we report an electron-beam induced formation of blue light emitting organosilicon nanoparticles (OSiNPs) in the micellar medium of Triton X-100 (TX-100). The profound role of the micellar medium can be realized from the enhanced colloidal stability as well as photoluminescence (PL) quantum efficiency (from ~9% to ~55%) of as synthesized OSiNPs. Mechanistic investigations revealed the crucial role of hydroxyl radical ([rad]OH) in the formation of OSiNPs. XPS and FTIR studies indicated the presence of siloxane/silicone and silica (SiO2) like units as the major constituents in the NPs. XRD pattern showed the amorphous nature of the NPs, while TEM studies revealed their aggregation. The hydrodynamic size of the NPs was determined to be ~24 nm. Interestingly, the NPs exhibited an excitation-wavelength-dependent PL behaviour, thereby indicating the presence of multiple emission centres (ECs). Detailed investigations based on steady-state as well as time-resolved PL measurements were conducted to analyse these ECs. In addition, pH and temperature-dependent studies were carried out to further substantiate these findings. Moreover, the experimental observations revealed their potential applications in the areas of thermosensing, fingerprinting and cell-imaging. Notably, the internalization of as prepared NPs within cells was evident from the bright fluorescence images obtained from the cytoplasmic region as compared to control cells. This observation also suggests the prospective application of these NPs for image guided drug delivery systems. 2021 Elsevier B.V. -
Individual effects of sinusoidal and non-sinusoidal gravity modulation on Rayleigh-Bard convection in a ferromagnetic liquid and in a nanoliquid with couple stress
The effects of sinusoidal (sine wave) and non-sinusoidal (square wave, triangular wave, and sawtooth wave) forms of gravity modulation on Rayleigh-Bard Convection (RBC) in a ferromagnetic liquid and a nanoliquid with couple stress is examined using linear and non-linear stability analyses. From the linear analysis, the stability of the system is investigated by calculating the correction Rayleigh number using the Venezian method. The heat transfer coefficient is obtained by solving the non-autonomous Lorenz equation. The influence of various non-dimensional parameters on the onset of convection and heat transfer is analyzed. It is observed that the couple stress parameter stabilizes the system and decreases the heat transfer. It is found that the square type of gravity modulation facilitates more heat transport compared to other types of gravity modulation. The ferromagnetic parameters are shown to have their known influence on the onset of convection and heat transport. The results of the single-phase ferromagnetic nanoliquid with couple stress are extracted from the results of the ferromagnetic liquid with couple stress. Advancement of onset due to nanoparticle presence and thereby enhanced heat transfer is discussed. The higher concentration of alumina is shown to be preferable to the rather expensive copper nanoparticles in obtaining the same quantity of heat transfer. 2021, The Author(s), under exclusive licence to EDP Sciences, SocietItaliana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature. -
Spectral quasi-linearization and irreversibility analysis of magnetized cross fluid flow through a microchannel with two different heat sources and Newton boundary conditions
Fluid flow in a microchannel with heat transport effects can be seen in various applications such as micro heat collectors, mechanicalelectromechanical systems, electronic device cooling, micro-air vehicles, and micro-heat exchanger systems. However, little is known about the consequence of internal heat source modulations on the flow of fluids in a microchannel. Therefore, in this work, the heat transfer of a magnetized cross fluid is carried out in a micro-channel subjected to two different heat source modulations. Entropy production analysis is also performed. The mathematical model consists of a cross fluid model. In addition, the effects of Joule heating, external magnetism, and the boundary conditions of Newton's heating are also examined. Determinant equations are constructed under steady-state conditions and parameterized using dimensionless variables. The numerical spectral quasi-linearization (SQLM) method was developed to interpret the Bejan number, entropy production, temperature, and velocity profiles. It is established that the power-law index of the cross fluid reduces the magnitude of the entropy production, velocity, and thermal field in the entire microchannel region. Furthermore, a larger Weissenberg number is capable of producing greater entropy, velocity, and thermal fields throughout the microchannel region. The variation in temperature distribution is more noticeable for the ESHS aspect than the THS aspect. The values of the pressure gradient parameter and the Eckert number must be kept high for maximum heat transport of the cross fluid. The entropy production of the cross fluid increases significantly with the physical aspects of Joule heating and convection heating in the system. 2021, The Author(s), under exclusive licence to SocietItaliana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature. -
The Role of Board Independence and Ownership Structure in Improving the Efficacy of Corporate Financial Distress Prediction Model: Evidence from India
The study aimed to investigate the role of non-financial measures in predicting corporate financial distress in the Indian industrial sector. The proportion of independent directors on the board and the proportion of the promoters share in the ownership structure of the business were the non-financial measures that were analysed, along with ten financial measures. For this, sample data consisted of 82 companies that had filed for bankruptcy under the Insolvency and Bankruptcy Code (IBC). An equal number of matching financially sound companies also constituted the sample. Therefore, the total sample size was 164 companies. Data for five years immediately preceding the bankruptcy filing was collected for the sample companies. The data of 120 companies evenly drawn from the two groups of companies were used for developing the model and the remaining data were used for validating the developed model. Two binary logistic regression models were developed, M1 and M2, where M1 was formulated with both financial and non-financial variables, and M2 only had financial variables as predictors. The diagnostic ability of the model was tested with the aid of the receiver operating curve (ROC), area under the curve (AUC), sensitivity, specificity and annual accuracy. The results of the study show that inclusion of the two non-financial variables improved the efficacy of the financial distress prediction model. This study made a unique attempt to provide empirical evidence on the role played by non-financial variables in improving the efficiency of corporate distress prediction models. 2021 by the authors. -
Multi-objective ANT lion optimization algorithm based mutant test case selection for regression testing
The regression testing is principally carried out on modified parts of the programs. The quality of programs is the only concern of regression testing in the case of produced software. Main challenges to select mutant test cases are related to the affected classes. In software regression testing, the identification of optimal mutant test case is another challenge. In this research work, an evolutionary approach multi objective ant-lion optimization (MOALO) is proposed to identify optimal mutant test cases. The selection of mutant test cases is processed as multi objective enhancement problem and these will solve through MOALO algorithm. Optimal identification of mutant test cases is carried out by using the above algorithm which also enhances the regression testing efficiency. The proposed MOALO methods are implemented and tested using the Mat Lab software platform. On considering the populace size of 100, at that point the fitness estimation of the proposed framework, NSGA, MPSO, and GA are 3, 2.4, 1, and 0.3 respectively. The benefits and efficiencies of proposed methods are compared with random testing and existing works utilizing NSGA-II, MPSO, genetic algorithms in considerations of test effort, mutation score, fitness value, and time of execution. It is found that the execution times of MOALO, NSGA, MPSO, and GA are 2.8, 5, 6.5, and 7.8 respectively. Finally, it is observed that MOALO has higher fitness estimation with least execution time which indicates that MOALO methods provide better results in regression testing. 2021 Scientific Publishers. All rights reserved. -
Efficient lipophilicity prediction of molecules employing deep-learning models
Lipophilicity, expressed as logP, is a significant physiochemical property and is an indicator of absorption, distribution, metabolism and elimination characteristics of drugs used in medication. It is one of the major deciding factors of the fate of a molecule to be a successful drug. Mol2vec is a convenient and unsupervised machine learning technique which produces high-dimensional vector representations of molecules and its molecular substructures. The work described here aims to simplify prediction of logP values with high-degree of accuracy by using Deep Learning (DL) models paired with Mol2vec. The work described in this paper empirically demonstrates that by using the described DL models paired with Mol2vec, one can achieve results which are much better than the conventional ML techniques as well as more complex and recent algorithms like Message-passing Neural Networks (MPNN), Graph Convolution (GC) and Spatial Graph embedding (C-SGEN). Our RMSE (Root Mean Square Error) scores from the ensemble model is one of the best reported so far in literature. The methods elaborated in this paper are simple, yet effective in predicting logP values to a great degree of accuracy due to the use of Mol2vec and standard TensorFlow operators. The models employed here can be coded and maintained with much more ease compared to the techniques of MPNN, C-SGEN or GC. 2021 Elsevier B.V. -
Anti-vibrio effects of the precious Tibetan pill, Rinchen Drangjor Rilnag Chenmo (RDRC)
Tibetan precious pills are an integral part of TTM (Traditional Tibetan Medicine). Among them, Rinchen Drangjor Rilnag Chenmo (RDRC) has been named King of Precious Pills due to its efficacy in treating a multitude of human disorders. RDRC has a complex formulation with about 140 ingredients, mostly from medicinal plants and a few precious stones and metals. Not many studies have been done on the experimental validation of antimicrobial properties of this important pill. The current study investigated the antimicrobial activity of the extracts of RDRC. Both aqueous and chloroform extracts were evaluated for their antibacterial potential against a total of seven different bacterial species, which are pathogenic, including three species of Vibrio, viz. V. vulnificus, V. parahaemolyticus and V. harveyi using the well-diffusion method and also by assessing MIC and MBC values. Its antifungal potential was also studied against two fungal strains Aspergillus Niger and Talaromyces islandicus. It was found that the chloroform extract of RDRC exerted a positive antibacterial effect on all the Vibrio species tested, and the least MIC of 3.33 mg/ml was observed for V. parahaemolyticus. This is the first study of its kind on the anti-Vibrio effect of the Tibetan precious pill, Rinchen Drangjor Rilnag Chenmo. Dhargyal et al (2021). This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited (https://creativecommons.org/licenses/by/4.0/). -
TenzinNet for handwritten Tibetan numeral recognition
Tibet is known for its enumerable collection of Nalanda based Buddhism manuscripts that need to be digitized for immortalization of the teachings of Buddha and various Buddhist scholars. Handwritten Tibetan numeral recognition is relatively unexplored as compared to Roman and Chinese numerals. Recognition of handwritten documents for digitalization has been under study from past many years. This work proposes a novel model using convolutional neural networks architecture named as TenzinNet to recognize handwritten Tibetan numerals. TenzinNet achieved an accuracy of 90.76% in recognizing Tibetan numerals using the proposed model. 2021, Bharati Vidyapeeth's Institute of Computer Applications and Management. -
Micro and nano Bi2O3 filled epoxy composites: Thermal, mechanical and ?-ray attenuation properties
Polymer composites have attracted considerable attention as potential light-weight and cost-effective materials for radiation shielding and protection. In view of this, the present work focusses on development of lead-free composites of diglycidyl ether of bisphenol A (DGEBA) epoxy resin with micro (~ 10 ?m) and nano (~ 20 nm) bismuth (III) oxide (Bi2O3) fillers, using solution casting technique. Thermal, mechanical and ?-ray attenuation properties of the composites were studied by varying the filler loading. Inclusion of the fillers into epoxy matrix was confirmed both structurally and morphologically by XRD and SEM, respectively. Thermogravimetric analysis (TGA) showed the thermal stability of composites to be as high as 400 C. The nanocomposites exhibited relatively higher thermal stability than their micro counterparts. Among the composites, 14 wt% nano-Bi2O3/epoxy composites showed highest tensile strength of 326 MPa, which is about 38% higher than 30 wt% micro Bi2O3/epoxy composites. Mass attenuation coefficients (?/?) of the composites were evaluated at ?-ray energies ranging from 0.356 to 1.332 MeV. Nanocomposites showed better ?-ray shielding at all energies (0.356, 0.511, 0.662, 1.173, 1.280 and 1.332 MeV) than micro composites with same filler loading. These studies revealed the significance of nano-sized fillers in enhancing overall performance of the composites. 2021 Elsevier Ltd -
A study of quadratic thermal radiation and quadratic convection on viscoelastic material flow with two different heat source modulations
In many practical applications such as plastic manufacturing and the polymer industries, the temperature difference is substantially large as a result the density of the working fluid alters nonlinearly with temperature. Therefore, the nonlinear Boussinesq (NBA) approximation cannot be ignored, as it has a considerable impact on the flow and heat transport characteristics of the working fluid. Here, the non-Newtonian viscoelastic material flow driven by stretching of elastic sheet subjected to NBA and quadratic form of Rosseland thermal radiation is investigated. Two different heat source modulations, viz., exponential space-dependent heat source, and a temperature-related heat source are analyzed. The viscoelastic material obeys the quadratic Boussinesq approximation. The fluctuation of plate temperature is linear and the transpiration (plate mass suction) is also accounted. The Darcy law is employed for a porous medium. The dimensionless profiles of the velocity, heat transport rate, and temperature are simulated by solving the nonlinear two-point boundary value system by employing the finite difference-based routine. The significance of key parameters involved in the problem is studied on various flow fields via surface and streamline plots. It is found that the quadratic convection mechanism enhanced the Nusselt number; however, the quadratic thermal radiation aspect reduced the Nusselt number. The higher velocities are captured in the case of quadratic thermal convection as compared with its absence. Whereas this trend is quite opposite for the thermal field. The velocity of viscoelastic material positively correlated with the viscoelastic material parameter. Further, the outcome of this investigation helps in determining the key parameters which facilitate the desired heat transport rate. 2021 Elsevier Ltd -
Moderating effects of academic involvement in web-based learning management system success: A multigroup analysis
While several educational institutions in India, in accordance to global practices, have adopted Web-Based Learning Management Systems (WLMS) to supplement classroom courses, it is largely seen that these WLMSs fail in their objectives, leading to little or no return on investments. The study aims to define the factors that affect students acceptance of a web-based learning management system and test the moderating effect of their academic involvement in the success of a WLMS. 477 valid questionnaires were collected from university/college students to empirically test the research model using the structural equation modelling approach. The results concludes that indirect and direct effects account for 49% of the variation in the intention to use, which is explained by technical system quality, information quality, educational quality, service quality of the technical support team and user satisfaction. High academic involvement moderates the impact of different service qualities of the WLMS on user satisfaction, intention to use the system, and success of the WLMS. Based on the findings, theoretical and managerial implications are discussed. 2021 -
Characterization of Line-Cut Signed Graphs
A signed graphS= (Su, ?) consists of an underlying graph Su and a function ?: E(Su) ? { + , - }. For a graph G, its lict graph written as Lc(G) is the intersection graph ?(E(G) ? C(G)). For a signed graph S, its line-cutsigned graph (in short called lict signed graph) is denoted by Lc(S) has underlying graph Lc(Su) and two vertices u and v joint by negative edge if u and v both are negative adjacent edges of S or u is a negative edge incident to a cut-vertex v of negative degree odd in S and by positive edge otherwise, here C(S) is the set of cut-vertices of S. In this paper, we establish structural characterization of lict signed graphs Lc(S). 2020, The National Academy of Sciences, India. -
Green Synthesis of Reduced Graphene Nanostructure from Cinnamomum Camphora
A facile green synthesis for carbon nanoparticle production using Cinnamomum camphora (Camphor) is presented. Camphor upon carbonization and chemical oxidation leads to the formation of nano-carbon structures with lateral size 7.33nm to 4.14nm, respectively. The nanomaterial's stacking height is about 2.76nm and 3.10nm, leading to the formation of about 10 layers of carbon. The AFM analysis confirms that the graphene layer formed is wrinkled or folded. Developments of a layered structure with spheroids are observed on the sample's surface, confirming the graphitization of the amorphous carbon. The relative intensity of the defect to the graphite band is found to be 0.98 for the nanostructure indicating a lesser degree of defects. The C1s band of the nanostructure is deconvoluted to components at 284.7, 286.5, 287.3, and 289 eV, which are assigned to non-oxygenated ring carbon (sp2 carbon), C in C-O (bound to O either as epoxy or hydroxyl), C in C=O (of alcohols, phenols or ether), and C in C(O)O (carboxylic acid) respectively. The study reveals the formation of few-layer oxygenated carbon layers from the botanical hydrocarbon. 2020 by the authors. -
An empirical analysis of sustainability of public debt among BRICS nations
The main objective of this paper is to verify the sustainability of public debt among Brazil, Russia, India, China and South Africa (BRICS) in a political economy framework. Annual panel data have been used for BRICS countries from World Development Indicators of World Bank for the period 19802017 for the analysis. Bohn's sustainability framework is used to examine the sustainability of public debt in BRICS nations and verify the influence of political economic variables such as election year, coalition dummy, ideology of the government and unemployment on public debt sustainability. The results suggest that public debt sustainability is weak for BRICS as a whole. China and India have a better public debt sustainability coefficients compared to the same for Brazil, Russia and South Africa. Structural change dummy included in the model suggests that debt sustainability is severely affected after the 2008 crisis period. Political factors have influence on debt sustainability in BRICS. Electoral cycle year and coalition dummy variables adversely affect public debt sustainability in BRICS. While centrist political ideology is found to be significant and negative, left and right ideologies are not significant for debt sustainability. Since debt sustainability is found to be weak in BRICS, countries in the region need to adopt necessary measures to improve their primary balance through appropriate fiscal and debt management. Besides, it is important for the governments to prioritize fiscal prudence irrespective of their ideologies and political compulsions. 2020 John Wiley & Sons, Ltd -
Future search algorithm for optimal integration of distributed generation and electric vehicle fleets in radial distribution networks considering techno-environmental aspects
In this paper, a new nature-inspire meta-heuristic algorithm called future search algorithm (FSA) is proposed for the first time to solve the simultaneous optimal allocation of distribution generation (DG) and electric vehicle (EV) fleets considering techno-environmental aspects in the operation and control of radial distribution networks (RDN). By imitating the human behavior in getting fruitful life, the FSA starts arbitrary search, discovers neighborhood best people in different nations and looks at worldwide best individuals to arrive at an ideal solution. A techno-environmental multi-objective function is formulated using real power loss, voltage stability index. The active and reactive power compensation limits and different operational constraints of RDN are considered while minimizing the proposed objective function. Post optimization, the impact of DGs on conventional energy sources is analyzed by evaluating their greenhouse gas emission. The effectiveness of the proposed methodology is presented using different case studies on Indian practical 106-bus agriculture feeder for DGs and 36-bus rural residential feeder for simultaneous allocation of DGs and EV fleets. Also, the superiority of FSA in terms of global optima, convergence characteristics is compared with various other recent heuristic algorithms. 2021, The Author(s). -
C-CORDIAL LABELING OF BIPARTITE SIGNED GRAPHS
Let ?:= (V, E) be a graph and ?:= (?, ?) be a signed graph with underling graph ?. Let : V (?) ?? {+, ?} be a C-marking. Then the function is called C-cordial labeling of signed graph ?, if |e? (?1) ?e? (1)| ? 1 and |v (?) ?v (+)| ? 1, where v (+) and v (?) are the number of vertices of ? having label + and ?, respectively under . In this paper, we have characterized signed cycles with given number of negative sections, which admit C-cordial labeling. We have also obtained a characterization of signed bistars which admit C-cordial labeling. 2021 Allahabad Mathematical Society. -
Antiferromagnetism of CoO-NiO bilayers studied by XMLD spectroscopy
CoO-NiO epitaxial bilayer system grown on MgO(001) substrate is investigated using x-ray magnetic linear dichroism (XMLD) spectroscopy with varying CoO overlayer thickness. An analysis of the Ni L 2 edge XMLD spectra using anisotropic XMLD formulation within a two-domain model reveals that the Ni moments undergo a spin reorientation with increasing CoO thickness. Such a spin reorientation is attributed to the competing magnetic interactions at both the NiO film interfaces, suggesting the existence of a sharp horizontal domain wall separating the in-plane and out-of-plane NiO domains. Our study also demonstrates a possible way to investigate the spin-structure along the thickness within the same chemical structure using a model-based approach, in a noninvasive manner. 2021 IOP Publishing Ltd.