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Nonlinear stability and dynamics of RayleighBard convection in variable viscosity ferromagnetic liquids
RayleighBard convection in ferromagnetic liquids provides a fundamental framework for understanding magneto-thermal transport in systems where buoyancy, magnetic forces and material properties interact. Most nonlinear studies of ferroconvection, however, assume constant viscosity, even though in practical ferrofluids viscosity may vary with temperature and be influenced by an applied magnetic field. In this work, we examine the stability and nonlinear dynamics of a Newtonian ferromagnetic liquid confined between rigid isothermal boundaries and subjected to a uniform vertical magnetic field, while explicitly accounting for viscosity variations arising from thermal and magnetic effects. Linear stability analysis is carried out using a truncated Galerkin approach, leading to an analytical expression for the stationary critical Rayleigh number that incorporates the viscosity-dependence parameter and magnetic numbers. To investigate post-onset behavior, a generalized Lorenz-type system is derived through a minimal FourierGalerkin truncation, allowing steady, oscillatory and irregular convection states to be explored within a low-dimensional nonlinear framework. Heat transport is interpreted through a Nusselt number formulation expressed in terms of the reduced system variables, with time-averaged values used in non-steady regimes. The model recovers established constant-viscosity ferroconvection results in the appropriate limiting case and demonstrates how viscosity variation modifies stability thresholds, amplitude saturation and convective transport trends. The present formulation provides a compact theoretical basis for assessing the combined influence of thermorheological and magnetorheological effects on convection dynamics in ferrofluid layers relevant to magnetic thermal control applications. The Author(s), under exclusive licence to SocietItaliana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2026. -
Nonlinear steady Darcy-Bard convection problem: Revisit using the heatlines approach
The classical problem of Darcy-Bard convection(DBC) in enclosures is revisited using the method of heatlines to have a better perspective of the problem. General aspect ratio is chosen in the analysis which helps in obtaining the results of four different types of enclosures, viz., tall, square, shallow and very shallow. Three different water saturated porous media(WSPM) and their actual thermophysical properties are used in the computation of the results. The method of heatlines facilitates the observation of fluid and heat flow lines in order to have a good understanding of the dynamics. The neo-classical approach not only accurately predicts the critical Darcy-Rayleigh and wave numbers but also picturizes the heat flow of the problem in the most natural way. The Galerkin method is used in the paper for the normal and convective modes of convection yields accurate analytical results in the heatlines formulation. Theoretical expression to calculate the number of Bard cells that form in the system at onset is obtained by linear theory, and ranges of aspect ratio at which unicellular, two-cellular and multicellular convection are possible are determined and documented. The weakly non-linear stability analysis is performed to determine the heat transport. Among four considered enclosures, maximum heat transport is achieved in the case of a square enclosure. Out of three chosen WSPM, the water-saturated glass balls porous medium and the water-saturated aluminium-foam porous medium show most stable and least stable behaviours. Results obtained from the heatlines approach are validated by comparing with the results of the classical DBC problem in the case of a very shallow enclosure. From the study, we conclude that the square enclosure with water-saturated aluminium-foam porous medium has possible application in heat removal systems. 2025 The Physical Society of the Republic of China (Taiwan) -
Nonlinear thermo-solutal convective flow of Casson fluid over an oscillating plate due to non-coaxial rotation with quadratic density fluctuation: Exact solutions
Purpose: The nonlinear density thermal/solutal fluctuations in the buoyancy force term cannot be ignored when the temperature/concentration difference between the surface and fluid is large. The purpose of this paper is to investigate the nonlinear density fluctuations across a flowing fluid with heat mass transfer effects on a non-axial rotating plate. Therefore, the impact of nonlinear convection in the flow of Casson fluid over an oscillating plate has been analytically investigated. Design/methodology/approach: The governing equations are modeled with the help of conservation equations of velocity, energy and concentration under the transient-state situation. The dimensional governing equations are non-dimensionalized by utilizing non-dimensional variables. Later, the subsequent non-dimensional problem has been solved analytically using Laplace transform method. Findings: The effects of thermal Grashof number, solute Grashof number, nonlinear convection parameters, Casson fluid parameter, unsteady parameter, Prandtl number as well as Schmidt number on hydrodynamic, thermal and solute characteristics have been quantified. The numeric data for skin friction coefficient, Nusselt number and Sherwood number are presented. It is established the nonlinear convection aspect has a significant influence on heat and mass transport characteristics. Originality/value: The effect of nonlinear convection in the dynamics of Casson fluid past an oscillating plate which is rotating non-axially is investigated for the first time. 2019, Emerald Publishing Limited. -
Nonlinear three-dimensional stretched flow of an Oldroyd-B fluid with convective condition, thermal radiation, and mixed convection
The effect of non-linear convection in a laminar three-dimensional Oldroyd-B fluid flow is addressed. The heat transfer phenomenon is explored by considering the non-linear thermal radiation and heat generation/absorption. The boundary layer assumptions are taken into account to govern the mathematical model of the flow analysis. Some suitable similarity variables are introduced to transform the partial differential equations into ordinary differential systems. The Runge-Kutta-Fehlberg fourth- and fifth-order techniques with the shooting method are used to obtain the solutions of the dimensionless velocities and temperature. The effects of various physical parameters on the fluid velocities and temperature are plotted and examined. A comparison with the exact and homotopy perturbation solutions is made for the viscous fluid case, and an excellent match is noted. The numerical values of the wall shear stresses and the heat transfer rate at the wall are tabulated and investigated. The enhancement in the values of the Deborah number shows a reverse behavior on the liquid velocities. The results show that the temperature and the thermal boundary layer are reduced when the non-linear convection parameter increases. The values of the Nusselt number are higher in the non-linear radiation situation than those in the linear radiation situation. 2017, Shanghai University and Springer-Verlag Berlin Heidelberg. -
Nonlocal analysis of Rayleigh-type wave propagating in a gradient layered structure
The present article aims to study the propagation behavior of Rayleigh-type waves using the nonlocal theory of elasticity in a layered structure constituted of a gradient transversely isotropic stratum perfectly bonded with a gradient monoclinic substrate. At first a constitutive relation is established for the assumed layered structure. Thereafter in view of suitable boundary conditions dispersion relation for the propagation of Rayleigh-type wave is obtained by considering a complex quantity wavenumber. The obtained result well agrees with the classical result and therefore validates the present study. The phase velocities and the attenuation coefficient for the Rayleigh-type wave propagation are numerically computed for the materials CdSe and LiNbO3; and the same are illustrated graphically. A significant effect of the affecting parameters on the propagation and the attenuation curves are depicted against the wavenumber. Comparative analysis of the influence of these parameters on the propagation and attenuation of Rayleigh-type waves is marked distinctly which serves as a salient feature of the present study. The techniques utilised the present problem and the obtained results may find potential application in various aspects. 2023, The Author(s), under exclusive licence to SocietItaliana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature. -
Nonlocal thermoelastic waves inside nanobeam resonator subject to various loadings
The present article focuses on the new meticulous model based on the postulate of memory-dependent derivatives to analyze the thermo-mechanical interactions inside the nano-beam-based machined resonators. Also, the size effect on dynamic responses of thermoelastic vibrations of homogeneous and isotropic nano-beam is considered. The fundamental expressions are formulated in the frame of non-local generalized thermoelasticity with paired relaxation times by operating the results of Euler-Bernoulli beam theory, non-local effect, and memory-dependent derivative. The proposed model is applied to study the nano-beam-based machined resonator subjected to the ramp-type heating and exponentially decaying time-dependent load. Closed-form solutions of the physical fields are examined by applying the Laplace transform mathematical mechanism. However, the coherence of the new thermal conductivity framework, a collation has been bestowed among the results obtained in the presence or absence of the memory-dependent derivative; also, the size effect is analyzed on the significant parameters of nano-beam such as deflection, temperature, displacement as well as bending moment. Moreover, the prominent influence of the distinct affecting parameters such as constituents of memory-dependent derivative (kernel function and time delay) and ramping time parameter with an applied load on the physical fields have been investigated with the help of quantitative results. 2022 Taylor & Francis Group, LLC. -
Nontoxic photoluminescent tin oxide nanoparticles for cell imaging: Deep eutectic solvent mediated synthesis, tuning and mechanism
Non-toxic and photoluminescent (PL) tin oxide nanoparticle synthesis in Deep Eutectic Solvents (DESs) is being reported herein. Both radiation (electron beam and ? radiation) and solvothermal methods were employed for the synthesis. An electron beam radiation technique proved to be more appropriate in tuning the size and morphology compared to the solvothermal process. Addition of any external oxido-reductive or stabilizing agent could be avoided by the use of Reline (choline chloride?:?urea; 1?:?2) as the host matrix. Detailed analysis of the PL behaviour of the nanoparticles is another important aspect of this study. The oxygen vacancies and tin interstitials responsible for photoluminescence have been identified from the de-convoluted PL spectra of the nanoparticles. Time dependent PL kinetics depicts PL decay at ?1.2 ns due to near band edge emission and at ?3.15 ns due to defect state emission. The synthetic process has been standardized focusing on the size of the particles by varying all possible experimental parameters such as the temperature, concentration of the precursors, reaction time, dose of irradiation and dose rate. Synthesized nanoparticles have been characterized using XRD, XPS and EDX. TEM images illustrate nanomorphological differences obtained in the two methods. The probable mechanism of synthesis (both radiation and thermal) has been proposed based on the results obtained from transient studies using electron pulses and FTIR experiments. Cytotoxicity data demonstrate that the nanoparticles are suitable for application in biological studies involving cells up to a concentration of 10 ?M. Imaging experiments with these photoluminescent nanoparticles exhibit their ubiquitous distribution including the nucleus of the tumour cells, which signifies potential application of these NPs for targeted drug delivery in cancer chemotherapy. Furthermore, the nanoparticles exhibited excellent antioxidant properties in vitro. The findings herein can open up enormous possibilities for more advanced and dedicated research towards using this cheap and versatile nanomaterial in a variety of biomedical applications. 2021 The Royal Society of Chemistry. -
Nontraditional security: Redefining state-centric outlook /
Jadavpur journal of International Relations, Vol.20, Issue 1, pp.102-124, ISSN: 0973-5984 (Print) 2349-0047 (Online). -
NorBlueNet: Hyperspectral imaging-based hybrid CNN-transformer model for non-destructive SSC analysis in Norwegian wild blueberries
Soluble solids content (SSC) is a vital parameter in blueberries, reflecting the concentration of dissolved sugars (primarily fructose and glucose) and directly influencing the fruit's sweetness, flavour, and ripeness. As part of this study, Norwegian wild blueberries were carefully hand-picked from a forest in Norway and subsequently imaged using a hyperspectral camera to capture their detailed spectral characteristics. This study introduces NorBlueNet, a hybrid CNN-transformer architecture, for accurately predicting SSC in wild blueberries through hyperspectral imaging and deep learning. This hybrid architecture combines CNN layers for local feature extraction and spatial hierarchy representation, followed by transformer layers that capture global relationships and long-range dependencies. The hybrid approach combines the computational advantages of CNNs with the advanced attention mechanisms of transformers, achieving enhanced accuracy while maintaining computational efficiency. A comprehensive evaluation is conducted by comparing the proposed model with two additional deep learning models on the custom dataset. The results indicate that the NorBlueNet achieves the highest prediction accuracy, with an R2 = 0.98, RMSE = 0.0136, and RPD = 9.3759 thereby demonstrating its superior performance. To foster community engagement, collaboration and facilitate re-implementation of our work, we have made our code available at:https://github.com/NorBlueNet. 2025 -
Normalized Attention Neural Network with Adaptive Feature Recalibration for Detecting the Unusual Activities Using Video Surveillance Camera
Over the past few years, surveillance cameras have become common in many homes and businesses. Many businesses still employ a human monitor of their cameras, despite the fact that this individual is more probable to miss some anomalous occurrences in the video feeds owing to the inherent limitations of human perception. Numerous scholars have investigated surveillance data and offered several strategies for automatically identifying anomalous occurrences. Therefore, it is important to build a model for identifying unusual occurrences in the live stream from the security cameras. Recognizing potentially dangerous situations automatically so that appropriate action may be taken is crucial and can be of great assistance to law enforcement. In this research work, starting with an MRCNN for feature extraction and AFR for fine-tuning, this architecture has a number of key components (AFR). To increase the quality of the features extracted by the MRCNN, the AFR replicas the inter-dependencies among the features to enhance the quality of the low- and high-frequency features extracted. Then, a normalized attention network (NAN) is used to learn the relationships between channels, which used to identify the violence and speeds up the convergence process for training a perfect. Furthermore, the dataset took real-time security camera feeds from a variety of subjects and situations, as opposed to the hand-crafted datasets utilized in prior efforts. We also demonstrate the method's capability of assigning the correct category to each anomaly by classifying normal and abnormal occurrences. The method divided the information gathered into three primary groups: those in need of fire protection, those experiencing theft or violence, and everyone else. The study applied the proposed approach to the UCF-Crime dataset, where it outperformed other models on the same dataset. 2023 WITPress. All rights reserved. -
Normalized group activations based feature extraction technique using heterogeneous data for Alzheimers disease classification
Several deep learning networks are developed to identify the complex atrophic patterns of Alzheimers disease (AD). Among various activation functions used in deep neural networks, the rectifier linear unit is the most used one. Even though these functions are analyzed individually, group activations and their interpretations are still not explored for neuroimaging analysis. In this study, a unique feature extraction technique based on normalized group activations that can be applied to both structural MRI and resting-state-fMRI (rs-fMRI) is proposed. This method is split into two phases: multi-trait condensed feature extraction networks and regional association networks. The initial phase involves extracting features from various brain regions using different multi-layered convolutional networks. Then, multiple regional association networks with normalized group activations for all the regional pairs are trained and the output of these networks is given as input to a classifier. To provide an unbiased estimate, an automated diagnosis system equipped with the proposed feature extraction is designed and analyzed on multi-cohort Alzheimers Disease Neuroimaging Initiative (ADNI) data to predict multi-stages of AD. This system is also trained/tested on heterogeneous features such as non-transformed features, curvelets, wavelets, shearlets, textures, and scattering operators. Baseline scans of 185 rs-fMRIs and 1442 MRIs from ADNI-1, ADNI-2, and ADNI-GO datasets are used for validation. For MCI (mild cognitive impairment) classifications, there is an increase of 14% in performance. The outcome demonstrates the good discriminatory behaviour of the proposed features and its efficiency on rs-fMRI time-series and MRI data to classify multiple stages of AD. 2024 Vaithianathan et al. -
North Korean Refugees in China: A Humanitarian Perspective
Most scholars opined that the famine of the 1990s in North Korea began a cascading effect on the refugee influx to China. The refusal of Chinese authorities to recognise North Korean defectors as refugees stems from an agreement between the two allies, The history of this crisis thus starts with the 1986 agreement signed between North Korea and China that binds China to repatriate any defectors back to the North Korean state. The Mutual Cooperation Protocol of 1986 1 has often been quoted by Chinese authorities to justify the repatriation of North Korean refugees. In the cases where refugees have not been repatriated, the lack of recognition by the Chinese State ensures that they are exploited in numerous ways, such as prostitution, bonded labour, torture, detention, forced abortions, denial of medical treatment and housing, etc. No true estimates exist on quantifying the North Korean refugee influx, as it would legitimise the propensity of the issue and bring to light rampant violations of human rights within Chinese borders. Many international stakeholders, like US Congressional Committees, UNHCR, major non-governmental organisations and recently, in April 2023, South Korea spoke on Chinas policy on North Korean refugees. China remains in violation of the 1951 UN Convention on Refugees as it continues to undertake forced repatriation and refuse to acknowledge North Korean migrants as refugees, instead branding them as illegal economic migrants. For China, human rights have always been viewed by the CCP as an internal matter. It is caught in a zero-sum game trying to protect its alliance with Democratic Peoples Republic of Korea (DPRK), while facing increasing pressure from various global actors. As of now, the non-recognition of defectors is in favour of China as recognition of refugees could destabilise the region, increase the influx of migrants into the industrial north-east already suffering from labour issues and bring it closer to the USAs ambit of influence in South Korea and hamper the Chinese influence over DPRKs nuclear programme. Additionally, recognition of refugees and ensuring rights of minority groups will further exacerbate the issues the Chinese State is facing from Uighurs and Tibetans. It is against this backdrop of national interest that the barefaced exploitation of North Korean defectors has occurred over the years in China. 2026 selection and editorial matter, Neeraj Singh Manhas, Nitan Sharma, and Abhinav Tomer; individual chapters, the contributors. -
Nouveau shoppers buying behavior pattern and perception towards luxury brands
The customer perception towards purchasing luxury brands has various psychological patterns and the behviour towards purchasing such brands differs accordingly. The main objective of the study is to map the nouveau shoppers mind-set towards shopping malls and to analyze the buying behavior pattern and perception towards luxury brand on shopping malls. For this purpose a sample of 130 was collected from the respondents were percentage analysis, descriptive statistics, Kruskall Wallis test and Oneway anova were used as tools to analye the data. The conclusion is that shopping malls have higher potentiality to pull the customers to visit their places but the conversion of making every customers purchasing in the mall is based on various factors of each individual shops. The conversion towards making the consumers purchasing the products can be done to attractive displays and understanding the mindset of modern shoppers towards various products and brand. 2020 Webology Center. -
Novel algorithm for control of a shunt active power filter based on a three-level voltage source inverter
A three-level voltage source inverter is utilized to implement a shunt active power filter. SVPWM technique is used in the control circuit to generate the required gate pulses for the voltage source inverter. Principle of operation and analysis of the control circuit is presented. The proposed control algorithm ensures balance of dc bus voltages. Hence this active power filter is ideally suited for high power drives and transmission systems. The simulation results are presented and analyzed. The THD of load current is reduced to 6.47 % from 28.795 % in steady operation. 2010 Institute of Thermomechanics AS CR. -
Novel Anchor Generation Based Residual Network for Object Tracking in Video-Surveillance Applications
The activity of the object in question is alerted directly upon completion of an effective object tracking. Dependent on hardware support or not, a strong object tracking protocol is required for a precise object tracking application. According to these methods, tracking an object accurately within a predetermined processing time window required a significant amount of computer complexity. In contrast, a variety of quality-degrading elements, including occlusion, shifting lighting, shadows, and so on, have an adverse effect on tracking. All of these tracking shortcomings will be fixed by a revolutionary residual network based on loss operator and anchor creation. Detection of object has concerns that rely on the process of feature extraction to afford efficient quality. For this purpose a model called ResNet has been used that comprises thirty layers and hence named as Resnet-thirty. These networks are a type of Convolutional Neural Network (CNN) that contain residual connections among various layers. The various merits of these connections is the network has the capability to learn the features of global, local and intermediate in parallel. As such, the system is robust against changes in lighting. These variations in light were understood in terms of tracking objects within a changing background. The proposed work uses MOT datasets. This dataset comprises of MOT 15, MOT16, MOT17 and MOT20. The results have been found by using these datasets. Hence, it evidently outperforms in terms of precision, recall, MOTA, IDF, MOTP, SAIDF and F1 measure to track the objects. The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2025. -
Novel Anti-Corrosion and Anti-Fouling Coatings and Thin Films
Nanomaterials and nanocomposite materials have been developed as corrosion inhibitors and are the most noble and effective alternatives to traditional organic corrosion inhibitors. Nanomaterials provide reasonably high anticorrosive activity in both aqueous and solution phases. A unified approach to this task is lacking, however, which highlights the role of all disciplines involved in the creation and use of corrosion protection coatings for metals. Fouling is the process of accumulating unwanted material that is mostly non-living and comprised of detritus and organic or inorganic compounds, or organisms, such as tiny viruses up to giant kelps. This book covers both the processes of biofouling and anti(bio)fouling, and the devices that stop the biofouling process. This book provides a missing synopsis by providing an understanding of the anticorrosive and anti-biofouling effects of nanomaterials and nanocomposites under different environments. It features an up-to-date picture of the quality and chemistry of a substrate surface, its proper preparation by conversion treatment, the function of resins and anticorrosive pigments in paints, and novel concepts for corrosion protection. 2024 Scrivener Publishing LLC. -
Novel Applications of Graphene and its Derivatives: A Short Review
Graphene, a layered allotropic form of graphitic carbon, has fascinated the scientific world since its discovery. Its unique structural, physical, chemical, mechanical, and electrical properties find application in many areas. Because of its large surface area and its apt electrical property, it is used in electromagnetic interference shielding. With excellent carrier mobility, it is used for sensing purposes. Mechanical strength and elastic properties coupled with its lightweight make graphene a promising material as a supercapacitor. The 2-dimensional structural properties of the graphene layers can be used for the purification treatment of water and gas. The number of research in graphene applications is increasing every day, showing the importance and excellency of graphene properties. This short review provides a comprehensive understanding of graphene's properties and progress in electromagnetic interference shielding, sensors, water treatment, energy production, storage, and conversion applications such as supercapacitors, fuel cells, solar cells and electrocatalysts. 2023 Bentham Science Publishers. -
Novel approach for nonlinear time-fractional Sharma-Tasso-Olever equation using Elzaki transform
In this article, we demonstrated the study of the time-fractional nonlinear Sharma-Tasso-Olever (STO) equation with different initial conditions. The novel technique, which is the mixture of the q-homotopy analysis method and the new integral transform known as Elzaki transform called, q-homotopy analysis Elzaki transform method (q-HAETM) implemented to find the adequate approximated solution of the considered problems. The wave solutions of the STO equation play a vital role in the nonlinear wave model for coastal and harbor designs. The demonstration of the considered scheme is done by carrying out some examples of time-fractional STO equations with different initial approximations. q-HAETM offers us to modulate the range of convergence of the series solution using ?, called the auxiliary parameter or convergence control parameter. By performing appropriate numerical simulations, the effectiveness and reliability of the considered technique are validated. The implementation of the new integral transform called the Elzaki transform along with the reliable analytical technique called the q-homotopy analysis method to examine the time-fractional nonlinear STO equation displays the novelty of the presented work. The obtained findings show that the proposed method is very gratifying and examines the complex nonlinear challenges that arise in science and innovation. 2023 Balikesir University. All rights reserved. -
Novel Approach for Osteoporosis Classification Using X-ray Images
This research delves into the technical advancements of image segmentation and classification models, specifically the refined Pix2Pix and Vision Transformer (ViT) architectures, for the crucial task of osteoporosis detection using X-ray images. The improved Pix2Pix model demonstrates noteworthy strides in image segmentation, achieving a specificity of 97.24% and excelling in the reduction of false positives. Simultaneously, the modified ViT models, especially the MViT-B/16 variant, exhibit superior accuracy at 96.01% in classifying osteoporosis cases, showcasing their proficiency in identifying critical medical conditions. These models are poised to revolutionize osteoporosis diagnosis, providing clinicians with accurate tools for early detection and intervention. The synergies between the Pix2Pix and ViT models open avenues for nuanced approaches in automated diagnostic systems, with the potential to significantly improve clinical results and contribute to the broader landscape of medical image analysis. As osteoporosis remains a prevalent and often undiagnosed condition, the technical insights from this study hold substantial importance in advancing the field, emphasizing the critical role of accurate diagnostic tools in improving patient care and health outcomes. 2025 Oriental Scientific Publishing Company. All rights reserved. -
Novel approach to the analysis of fifth-order weakly nonlocal fractional Schringer equation with Caputo derivative
The main goal of this study is to find solutions for the fractional model of the fifth-order weakly nonlocal Schringer equation incorporating nonlinearity of the parabolic law and external potential using a recent modification of the homotopy analysis method (HAM) called the q-homotopy analysis transform method (q-HATM). A mixture of q-HAM and Laplace transform is the projected solutions procedure. The method contributes approximate and exact (for some special cases) solutions such as the bright soliton, dark soliton, and exponential solutions. The simulation results using Mathematica package software, demonstrate that only a few terms are enough to achieve precise, effective, and reliable approximate solutions. In addition, in terms of plots for varying fractional order, the physical behavior of q-HATM solutions has been depicted and the numerical simulation is also exhibited. The results of q-HATM reveal that the projected method is competitive, reliable, and powerful for studying complex nonlinear models of fractional type. 2021 The Authors