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Rayleigh-B nard convection in Casson and hybrid nano uids: An analytical investigation
The thermal Rayleigh-Bard convection (TRBC) in two different fluids namely Casson fluid and hybrid nanofluid is investigated analytically. The stability analysis is performed in both linear and non-linear form. The nanofluid properties like thermal conductivity, viscosity, thermal expansion coefficient and density are considered to be functions of the volume fraction of nanoparticles whereas the same properties of Casson fluid are assumed to be constant. The amount of heat transfer is analyzed in the non-linear analysis using the generalized Lorenz model. The influence of Casson fluid parameter and nanoparticles (single and or binary) which affect the onset of convection is analyzed. It is found that hybrid nanofluid delays the convection and will further enhance the heat transfer rate. Also, the Casson parameter advances the convection while it reduces the heat transfer rate. 2019 by American Scientific Publishers. -
Rayleigh-Bard convection in mono and hybrid nanoliquids in an inclined slot
Linear stability analysis is conducted to investigate the longitudinal and transverse rolls (TRs) generated in Rayleigh-Bard convection in mono and hybrid nanoliquids confined between two infinite inclined parallel slots. Thermophysical properties of six mono nanoliquids and fifteen hybrid nanoliquids are calculated for different volume fractions (0.5%, 1%, 2%) using phenomenological laws and mixture theory. The shooting method is used to solve boundary eigenvalue problems to obtain the eigenvalues for 16 different boundary conditions. It is observed that as the inclination angle is increased, it delays the onset of longitudinal rolls in the case of all boundary conditions. However, it advances the onset of TRs except when the lower plate is adiabatic. The addition of mono and hybrid nanoparticles results in the advancement of the onset of convection. The addition of SWCNT and SWCNT Al 2 O 3 accelerates the onset of convection the most while Cu and Cu-Ag accelerates the onset of convection the least amongst the mono and hybrid nanoparticles considered in the study. 2023 IOP Publishing Ltd. -
Rayleigh-Bard Convection of Water-Copper and Water-Alumina Nanofluids Based on Minimal- and Higher-Mode Lorenz Models
Linear and nonlinear stability analyses of Rayleigh-Bard convection in water-copper and water-alumina nanofluids are studied in the paper by considering a minimal as well as an extended truncated Fourier representation. These representations respectively result in a third-order classical Lorenz model and a five-dimensional extended Lorenz model. The marginal stability plots reveal that the influence of added dilute concentration of nanoparticles in water is to destabilize the system. The rate of destabilization depends on the nanoparticles' thermophysical properties and their volume fraction. Influence of adding an additional mode in the horizontal direction is to modify the cell size. This can be observed through the marginal curves as well as the stream line plots. Further, from the Nusselt number plots it is evident that the presence of dilute concentration of nanoparticles in water is to enhance heat transport in the system significantly. The dynamical behavior of the minimal and the extended Lorenz models is investigated using the bifurcation diagram. From the study an important finding that emerges is that the Fourier truncated solution is predicted to have different effects in lower-order and higher-order models. The extended penta-modal Lorenz system predicts advanced onset of chaos compared to that predicted by the classical third-order Lorenz model. The individual influence of both nanoparticles in water is to advance the onset of convection as well as to advance the onset of chaos. 2023 World Scientific Publishing Company. -
Rayleigh-benard convection in a dusty newtonian nanofluid with and without coriolis force
Theoretical investigation of the Rayleigh-Bard convection (TRBC) in nanofluid (NF) submerged with dust particles is carried out. Convection in dusty nanofluid is considered between two horizontal free boundaries. Effect of nanoparticles shape is also accounted. The Saffmans dusty fluid model is used to simulate the influence of dust particles, whereas the KVL (Khanafer-Vafai-Lightstone) model is employed to estimate the effective nanofluid properties. The fluid, dust particles and nanoparticles are in the thermal equilibrium state and move with the same velocity. The exact solutions are obtained using Normal Mode Analysis (NMA) method for two different cases namely (1) TRBC in dusty nanofluid (DNF) without Coriolis force (2) TRBC in DNF with Coriolis force. It is established that for the stationary convection, the effect of suspended particles hasten the onset of convection whereas the Coriolis force postpones the onset of convection. 2018 by American Scientific Publishers All rights reserved. -
Rayleigh-Benard convection in a horizontal layer of porous medium saturated with a thermally radiating dielectric fluid /
IOSR Journal Of Mathematics, Vol.11, Issue 3, pp.465-474, ISSN No: 2278-5728 (Online) 2319-765X (Print). -
Rayleigh-Type Surface Waves in Piezo-Thermoelastic Materials: A Comparative Study Using GreenNaghdi III and Three-Phase-Lag Models with Machine-Learning Surrogates
Abstract: In this work, the GreenNaghdi type III (GN-III) and Three-Phase-Lag (TPL) thermoelastic theories are used to investigate Rayleigh-type surface wave propagation in a transversely isotropic piezo-thermoelastic half-space. Phase velocity, attenuation, and specific loss may be thoroughly evaluated thanks to the derivation of secular equations for electrically open/shorted and thermally insulated/isothermal boundary conditions. The findings indicate that attenuation and loss show a substantial dependency on boundary restrictions and the chosen thermoelastic model, but phase velocity increases with inclination angle and stabilises for high wave numbers. The TPL framework predicts somewhat greater velocities and damping because of thermal relaxation effects, while electrically shorted isothermal surfaces produce the lowest dissipation. By explicitly incorporating governing equations into its loss function, a Physics-Informed Neural Network (PINN) is utilised to overcome the computational burden of solving difficult transcendental equations. The PINN provides an effective stand-in for optimisation and real-time diagnostics in SAW sensors, ultrasonic devices, and smart piezoelectric materials by precisely reconstructing dispersion trends from sparse analytical data. Pleiades Publishing, Ltd. 2025. -
RayleighBard and BardMarangoni magnetoconvection in variable viscosity finitely conducting liquids
The thermorheological effect on magneto-Bard-convection is studied numerically in fluids with finite electrical conductivity. A nonlinear thermorheological equation is considered in the problem. The results are compared with the classical approach of constant viscosity, which depicts the fact that the effect of increasing the strength of the magnetic field is to delay the onset of convection. The magnetic field is shown to have a rheostatic influence on convective instabilities. The results obtained by the study have possible applications in the field of astrophysics, sunspots, and in space applications under microgravity. 2021 Wiley Periodicals LLC -
RayleighBard Convection in a Bi-viscous Bingham Fluid with Weak Vertical Harmonic Oscillations: Linear and Non-linear Analyses
Linear and weakly non-linear stability analyses of RayleighBard convection in a bi-viscous Bingham fluid layer are performed in the presence of vertical harmonic vibrations. In the linear analysis, expression is obtained for the correction Rayleigh-number arising due to the vibrations. The non-linear-analysis based on the GinzburgLandau equation is used to compute the Nusselt-number in terms of the correction Rayleigh-number. The mean-Nusselt-number is then obtained as a function of the scaled-Rayleigh-number, the frequency and the amplitude of modulation, the Prandtl number, and the bi-viscous Bingham fluid parameter. The non-autonomous amplitude-equation is numerically solved using the RungeKuttaFehlberg45 method. It is found that the influence of increasing the amplitude of modulation is to result in a delayed-onset situation and thereby to an enhanced-heat-transport situation. For small and moderate frequencies, the influence of increasing the frequency of oscillations is to decrease the critical Rayleigh-number. However, the mean-Nusselt-number decreases with increase in the frequency of oscillations only in the case of small frequencies. An increase in the value of the bi-viscous Bingham fluid parameter leads to advanced-onset and thereby to an enhanced-heat-transport situation. At very large frequencies, the effect of modulation on onset and heat-transport ceases. 2023, The Author(s), under exclusive licence to Springer Nature India Private Limited. -
RayleighBard convection in a BoussinesqStokes ferromagnetic fluid under sinusoidal and non-sinusoidal internal heat modulation
Internal heat modulation has several applications in nuclear reactor design and safety, as well as meteorology. In this paper, the influence of internal heat modulation on RayleighBard convection in a BoussinesqStokes ferromagnetic fluid is explored using linear and nonlinear analyses. The impact of the square, sine, triangular, and sawtooth wave type of internal heat modulation on the onset of convection and heat transport is considered. Using a Venezian method, linear stability analysis is performed to derive the correction Rayleigh number and the critical Rayleigh number for all four waveforms. A nonautonomous Lorenz model is derived and solved for the amplitude to obtain the Nusselt number, which quantifies the heat transport. The impact of the nondimensional parameter on the convective onset and heat transfer under heat source/sink modulation is analyzed. The study shows that all four types of internal heat modulation destabilize the system. It is also found that the presence of a heat source/sink modulation affects the impact of all four types of internal heat modulation on heat transport. 2022 Wiley Periodicals LLC. -
RayleighBard convection in a non-Newtonian dielectric fluid with MaxwellCattaneo law under the effect of internal heat generation/consumption
Purpose: The study of instability due to the effects of MaxwellCattaneo law and internal heat source/sink on Casson dielectric fluid horizontal layer is an open question. Therefore, in this paper, the impact of internal heat generation/absorption on RayleighBard convection in a non-Newtonian dielectric fluid with MaxwellCattaneo heat flux is investigated. The horizontal layer of the fluid is cooled from the upper boundary, while an isothermal boundary condition is utilized at the lower boundary. Design/methodology/approach: The Casson fluid model is utilized to characterize the non-Newtonian fluid behavior. The horizontal layer of the fluid is cooled from the upper boundary, while an isothermal boundary condition is utilized at the lower boundary. The governing equations are non-dimensionalized using appropriate dimensionless variables and the subsequent equations are solved for the critical Rayleigh number using the normal mode technique (NMT). Findings: Results are presented for two different cases namely dielectric Newtonian fluid (DNF) and dielectric non-Newtonian Casson fluid (DNCF). The effects of Cattaneo number, Casson fluid parameter, heat source/sink parameter on critical Rayleigh number and wavenumber are analyzed in detail. It is found that the value Rayleigh number for non-Newtonian fluid is higher than that of Newtonian fluid; also the heat source aspect decreases the magnitude of the Rayleigh number. Originality/value: The effect of MaxwellCattaneo heat flux and internal heat source/sink on Rayleigh-Bard convection in Casson dielectric fluid is investigated for the first time. 2020, Emerald Publishing Limited. -
RayleighBard magnetoconvection with asymmetric boundary condition and comparison of results with those of symmetric boundary condition
The paper concerns two RayleighBard magnetoconvection problems, one in a mono-nanofluid (H2OCu) and the other in a hybrid nanofluid (H2OCuAl2O3) bounded by asymmetric boundaries. A minimal FourierGalerkin expansion is used to obtain the generalized Lorenz model (GLM) which is then reduced to an analytically solvable GinzburgLandau equation using the multiscale method. The results of asymmetric boundaries are extracted by using the Chandrasekhar function with appropriate scaling of the Rayleigh number and the wave number. The solution of the steady-state version of the GLM is used to estimate the Nusselt number analytically, and the unsteady version is solved numerically to estimate the time-dependent Nusselt number and also to study regular, chaotic, and periodic convection. Streamlines are plotted and analyzed in both steady and unsteady states. The analytical expression for the HopfRayleigh number, rH , coincides with the value predicted using the bifurcation diagram. This number determines the onset of chaos. For r?> rH , one observes chaotic motion with spells of periodic motion in between. For r?< rH , one sees non-chaotic motion (regular motion). It is found that by increasing the strength of the magnetic field, we can prolong the existence of regular motion by suppressing the manifestation of chaos. The Lorenz attractor is a signature of chaos since it is found that the attractor appears only for r?> rH . The magnitude of the influence of the asymmetric boundary on rH is between those of the two symmetric boundary conditions with the freefree isothermal boundary being the one that most favors chaotic motion: A result also seen in the context of regular convection. 2023, Akadiai Kiad Budapest, Hungary. -
Rays Women and Sartorial Choices: Exploring Through Colonial and Feminist Perspective
[No abstract available] -
RCBAM-CNN: Rebuild Convolution Block Attention Module-based Convolutional Neural Network for Lung Nodule Classification
Lung cancer remains the leading cause of cancer-related deaths worldwide. Pulmonary nodules, indicative of tumor growth, present significant diagnostic challenges due to their varying sizes and shapes. Computed Tomography (CT) is commonly used for lung cancer screening due to its high sensitivity and efficacy in detecting these nodules. However, differentiating between benign and malignant nodules can be difficult due to their overlapping characteristics. To address this challenge, we propose a Rebuild Convolution Block Attention Module-based Convolutional Neural Network (RCBAM-CNN) designed to accurately classify lung nodules from CT scans. The RCBAM-CNN integrates a Rebuild Convolution Block Attention Module (RCBAM), which includes reshaped layers and redefined spatial attention mechanisms to enhance the networks focus on relevant features while minimizing noise. The performance of the proposed method is evaluated using the LIDC-IDRI dataset. Data augmentation techniques, including rotation, rescaling, and both vertical and horizontal flips, are applied to improve the models robustness and generalization. Subsequently, U-Net is employed for precise image segmentation, ensuring accurate delineation of nodule regions. The proposed RCBAM-CNN demonstrates exceptional performance, achieving an accuracy of 99.72%, surpassing existing methods such as adaptive morphology with a Gabor Filter (GF) and Capsule Network-based CNN. This approach represents a significant advancement in lung nodule classification, offering improved diagnostic accuracy and reliability. 2024 River Publishers. -
Re-evaluating Emperor Asoka a relational contract theory explanation for economic transformation
Emperor Asoka's rein is considered an important era in ancient Indian history because of the vastness of his empire and the Buddhist elements in his administration. We propose that in addition to these reasons for highlighting Asoka's rein, there is an important economic argument as well. It was during the century or two around Asoka's rule that the subcontinent's economy underwent a transformation from a simple pastoralagricultural economy to a more mature economy with large scale production, specialisation and trade. The element that Asoka introduced into the social relations in his empire is Buddha's Dhamma, which formed and strengthened relational contracts. A key feature of relational contracts is incompleteness of arrangements that is managed by social iterations and formal and informal enforcement mechanisms. Each of these is reflected in Asoka's edicts, the earliest surviving writing samples from the subcontinent. Asoka planned for these measures to ensure political and economic stability. In addition, he also laid the most important foundational material in a rather unique way for all future economic transformations. 2017 Journal of Dharma: Dharmaram Journal of Religions and Philosophies (DVK, Bangalore). -
Reaction of Indian Stock Market to Outbreak of COVID-19: An Empirical Analysis of Extreme Inter-day Movements
The contagious COVID-19 pandemic has been considered a massive global crisis since World War II and has disturbed business and economic activities across the globe. The current study examined the reaction of the stock markets to the outbreak of COVID-19, considering the extreme inter-day movements in the Indian stock market. The extreme inter-day movements in S&P CNX Nifty-50 have been identified during the study period from January 2020 to December 2021 and further classified into decline and gain events based on positive and negative announcements related to COVID-19. The study utilized an event study approach and panel regression for empirical investigation. The results of the event study analysis illustrate that the significant abnormal loss ranges from 12.86% to 2.47% for the major decline events and significant abnormal return from 8.43% to 3.23% for the gain events. The regression analysis results showed that real return and Central Bank Policy rate have a considerable impact on the abnormal returns during COVID-19. The studys findings are helpful to policy implications that identified the need to focus on financial education and strengthen the health and finance-related policies to deal with such pandemics in the future. 2023 MDI. -
Readiness factors for information technology adoption in SMEs: testing an exploratory model in an Indian context
Purpose: Extant literature regarding factors essential for successful information technologies (IT) implementation in small and medium enterprises (SMEs) does not significantly address readiness factors for IT implementation in an Indian context. This exploratory research develops and tests a framework to analyse the antecedents to organisational preparedness for adoption of IT infrastructure in SMEs. Design/methodology/approach: This exploratory research adopts a mixed-method approach to test the technology, organization and environment (TOE) framework. In-depth interviews with SME owners are conducted to develop the case study, and the measures obtained are tested through a survey at a small and medium business industrial cluster in Southern India in SMEs. Findings: The case study indicates SME owners drive to initiate technology preparedness for organisational sustainability is a key factor, a measure not seen during the literature review. An empirical study tests the measures. Pressure from customers, owners age, sales of SME, owners attitude towards IT and owners knowledge of IT was confirmed, which indicates organisational factors have more impact compared to technological and environmental factors. Research limitations/implications: The academic scope of this research paper can be extended to contexts such as readiness in IT infrastructure for digital transformation. Practical implications: The validated research framework can be used by organisation stakeholders and SME IT practitioners for successful IT adoption. Social implications: SMEs contribute significantly to gross domestic product (GDP) and provide employment opportunities. Hence, this research provides a tested model that SMEs owners/managers can adopt as a framework to augment competitiveness to implement IT. Originality/value: The study adopts a mixed-method research design and is, perhaps, a first in the Indian context to explore variables through case study and validate identified measures through an empirical study. The model can be used by SME owners and practitioners to ascertain factors for organisational preparedness for IT adoption. 2019, Emerald Publishing Limited. -
READING AND ENGAGING WITH KACEN CALLENDERS MOONFLOWER THROUGH INTERSECTIONAL PEDAGOGIES
This chapter argues that privileged perspectives can be decentered using intersectional pedagogies when engaging with literary texts such as Moonflower, a novel that engages children with vital topics relating to race, gender, and mental health. 2024 selection and editorial matter, KaaVonia Hinton and Karen Michele Chandler; individual chapters, the contributors. All rights reserved. -
Reading behind the tweets: A sentiment Clustering Approach
Market sentiment influence crude oil future prices in direct or indirect way. In order to measure the polarity of market sentiment various techniques has been deployed by industry and academia alike. This pilot study successfully introduced two instruments, namely topic modeling and Sentiment clustering, to unearth the prevailing sentiments behind crude oil future pricesThree main conclusions that can be drawn from empirical results are. First, the K-Means clustering algorithm is an effective technique for sentiment clustering compared to Louveian and MDS clustering techniques. Second sentiment polarity-related positive sentiments have shown more variations in comparison to neutral and negative sentiments. Third It is possible to extract the keywords related to essential factors influencing crude oil prices using the LDA technique under topic modeling 2022 IEEE. -
Reading Patterns, Engagement Style and Theory of Mind
Theory of mind (TOM) refers to a set of abilities which enables understanding of mental states including beliefs, emotions and intentions of self and others. The purpose of this paper is to study the effect of different reading patterns including frequency of reading fiction and genre preference on TOM performance. It also aims to compare the accuracy of TOM performance under explicit goal directed and non-directed reading conditions. To achieve this objective, a sample of 72 Indian college students were randomly allocated to two groups and were evaluated on the Reading the Mind in the Eyes Test (RMET) and the Short Story Task (SST). The two groups differed with respect to task instructions aimed at mobilizing different manner of engagement (goal directed and nondirected) with the prose in the SST. The individual reading habits and preferences of all the participants were recorded by a self report questionnaire. Scores on the novel SST showed significant positive correlation with RMET scores. No significant difference in TOM performance with respect to the different engagement styles was found, indicating that TOM abilities function continuously and equally effectively when being used in goal directed and nondirected conditions. Notably, participants who reported to prefer literary fiction performed significantly better on the SST task than the participants who prefer popular fiction. This positive link between literary fiction and TOM has important implications in clinical and developmental fields and necessitates further research. 2021, National Academy of Psychology (NAOP) India. -
Reagent-Controlled Divergent Synthesis of 2-Amino-1,3-Benzoxazines and 2-Amino-1,3-Benzothiazines
A reagent-controlled chemoselective process has been devised for the synthesis of 4H-1,3-benzoxazines and related biologically important heterocycles in high yields under mild conditions. These scaffolds could be efficiently constructed using two different chemoselective reactions that rely on the choice of reagents and reaction conditions. The treatment of various 2-amino-arylalkyl alcohols with isothiocyanates afforded thiourea intermediates, which were reacted in situ with molecular iodine in the presence of triethylamine to give 2-amino-4H-1,3-benzoxazines, whereas the corresponding 2-amino-4H-1,3-benzothiazines were obtained by the reaction of thiourea intermediates in the presence of T3P (a mild cyclodehydrating agent) and triethylamine as the base. The described protocol represents the first example for the synthesis of 4H-1,3-benzoxazines via the dehydrosulfurization method using molecular iodine as the reagent. Copyright 2019 American Chemical Society.