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Study of nanofluid flow and heat transfer in a stationary cone-disk system
Rheometric, viscosimetric, bio-medical, and several other pharmaceutical machineries utilize the structural advantages provided by the geometry of a stationary conical diffuser. The problem of the Buongiorno nanofluid flow in the conical gap of a stationary cone-disk system for isothermal boundaries is studied. The governing system, comprising the incompressibility condition, NavierStokes equation, energy conservation equation, and conservation of Nanoparticle Volume Fraction (NVF) equation, is analyzed. The Lie-group theory has been used to derive a self-similar model. Solutions of the self-similar equations were computed numerically, and the expressions for the Nusselt number and Sherwood number are obtained. The parametric investigation reveals that the heat and mass transfer rate subside significantly when pre-swirl is introduced to the flow. Furthermore, the nanofluid slip mechanisms enhance the effective temperature of the system. 2023 Elsevier Ltd -
Study of nanofluid flow in a stationary cone-disk system with temperature-dependent viscosity and thermal conductivity
The substantial temperature gradient experienced by systems operating at relatively high temperatures significantly impacts the transport characteristics of fluids. Hence, considering temperature-dependent fluid properties is critical for obtaining realistic prediction of fluid behavior and optimizing system performance. The current study focuses on the flow of nanofluids in a stationary cone-disk system (SCDS), taking into account temperature-dependent thermal conductivity and viscosity. The influence of Brownian motion, thermophoresis, and Rosseland radiative flux on the heat transport features are also examined. The Reynolds model for viscosity and Chiam's model for thermal conductivity are employed. The Navier-Stokes equation, the energy equation, the incompressibility condition, and the continuity equation for nanoparticles constitute the governing system. The Lie-group transformations lead the self-similar ordinary differential equations, which are then solved numerically. Multi-variate non-linear regression models for the rate of heat and mass transfers on the disk surface were developed. Our study reveals a notable decrease in the rate of heat and mass transfer when pre-swirl exists in the flow. The significant influence of nanofluid slip mechanisms on the effective temperature and nanofluid volume fraction (NVF) within the system is highlighted. Furthermore, the variable viscosity property enhances the temperature and NVF of the SCDS. 2024 Author(s). -
Study of Natural Convection with Local Thermal Non Equilibrium Effects in Nanoliquid-Saturated Low Porosity Enclosures
Natural convection of nanoliquid in densely packed vertical porous enclosure is studied by subjecting the vertical walls to constant heat flux under local thermal non-equilibrium (LTNE) assumptions. Water, copper nanoparticles and porous material made of aluminum foam, glass balls and sand are considered for the study. The governing equations are modelled using single-phase model. Thermophysical properties of nanoliquid and nanoliquid-saturated porous medium are calculated using phenomenological laws and mixture theory. An analytical expression for velocity and temperature profiles of nanoliquid (base liquid+nanoparticles) and solid (porous medium) phases has been obtained. Weighted average Nusselt number is expressed as a function of aspect ratio, volume fraction, and properties concerning LTNE effects. LTNE effect is shown to be a heat transfer enhancing mechanism. The presence of nanoparticles is to enhance the heat transfer in water. Local thermal equilibrium results are obtained as a limiting case of the present study and so obtained results are compared with previously published paper in the literature. 2022, The Author(s), under exclusive licence to Springer Nature India Private Limited. -
Study of Optimization Techniques in Agriculture
In agriculture, optimization strategies are essential for raising production, sustainability, and resource efficiency. This abstract explores several agricultural optimization approaches and highlights their importance in contemporary farming operations. Obstacles to traditional agricultural operations include climate change, resource constraint, and shifting consumer preferences. Through the application of cutting-edge technologies and rigorous scientific methods, optimization strategies provide answers to these problems. Precision agriculture, which uses data-driven techniques like remote sensing, Geographic Information System (GIS), and Global Positioning System (GPS) to customize farming procedures to particular field conditions, is one important area of optimization. This helps farmers to maximize yields while minimizing waste and the environmental effect of inputs like water, fertilizer, and pesticides. In addition, optimization methods include selective breeding for genetic advancements and biotechnology, with the goal of creating crops with increased nutritional value, disease resistance, and production potential. Under the category of optimization approaches are integrated pest management solutions, which efficiently control pests and illnesses while using less chemical pesticides by applying ecological principles. In summary, agricultural optimization approaches offer a comprehensive strategy to tackle the issues that contemporary farming faces, encouraging resilience, productivity, and sustainability in food production systems. Given the changing global agricultural dynamics, it is imperative that these strategies be further researched and used in order to ensure environmental stewardship and food security. 2026 Scrivener Publishing LLC. All rights reserved. -
Study of rotating Bard-Brinkman convection of Newtonian liquids and nanoliquids in enclosures
Taylor-Bard convection of water and water-based nanoliquids confined in three different types of high porosity rectangular enclosures, viz., shallow, square and tall, is studied analytically using both infinitesimal and finite amplitude stability analyses. We make use of the modified-Buongiorno-Brinkman model(MBBM) for the governing equations concerning nanoliquid-saturated porous enclosures bounded by rigid-rigid boundaries and obtain analytical results. Among three types of enclosures, maximum and minimum heat transfers are observed in tall and shallow enclosures respectively. Water well dispersed with a dilute concentration of single-walled carbon nanotubes(SWCNTs) is considered as a working medium. The water-SWCNTs is able to flow in the porous medium because the medium is loosely-packed with porosity in the range 0.5 ? ? ? 1. In addition to this, the maximum volume fraction of nanoparticles considered in the system is 6% and thus this does not alter the fluidity of the system. We found from the study that the presence of low concentration(volume fraction-0.06) of SWCNTs in a water-saturated porous medium effectively improves the heat transport of the system due to its high thermal conductivity and large surface area. Due to the presence of a porous medium, however, the onset of convection gets delayed and heat transport in nanoliquids gets substantially reduced in a Bard-Brinkman configuration resulting from the weak thermal conductivity of the porous medium. Thus the porous medium acts as the heat storage system. Also, in a rotating frame of reference the heat transport gets reduced and rotation serves as an external mechanism of regulating heat transport in the system. The nonlinear dynamics of the system is studied using the 6-mode Lorenz model. Chaotic motion in the system is studied using the maximum Lyapunov exponent(MLE). The Hofp-bifurcation point of the system along with the MLE is used to investigate periodic, nearly periodic and mildly chaotic behaviors of the system. 2020 -
Study of SH wave propagation in Piezo-material semiconductors with differential imperfect contact mechanism by approximating higher-order quasi-classical method
This study investigates the propagation of a Love-type wave in a multiferroic solid cylindrical shell structure with an imperfect magneto-electroelastic (MEE) interface. An analytical solution for the layer is derived using the spatially variable Quasi-Classical approach. A numerical example illustrates the significant impact of various parameters on the wave's phase velocities and attenuation coefficients. Additionally, graphical comparisons are presented to evaluate the effects of mechanical, electrical, magnetic, electro-mechanical, magneto-mechanical, and magneto-electrical imperfections under electrically and magnetically open and short boundary conditions. The results reveal that the electrically and magnetically open case exhibits significantly higher phase velocities compared to the short case. Key findings are the following: the bonding parameter is directly proportional to phase velocity but inversely proportional to the attenuation coefficient, and imperfection parameters profoundly influence both the phase velocity and attenuation coefficient profiles. This theoretical study provides valuable insights into piezoelectric and piezomagnetic coupling mechanisms, highlighting their potential applications in designing advanced devices such as sensors, actuators, energy harvesters, and nano-electronic systems. The novelty of this work lies in the application of the Quasi-Classical approach to solving differential equations for the first time in a polar coordinate system. IMechE 2025 -
Study of stacking structure of amorphous carbon by X-ray diffraction technique
Random layered (graphene) structural parameters of the coals such as aromaticity fa, coal rank, number of carbon atoms per aromatic lamellae (n), lateral size La and stacking height Lc are determined using X-ray diffraction technique (XRD). It is found that the structural parameters like fa & Lc increases, where as interlayer spacing d002 decreases with increase in carbon content, aromaticity and coal rank. The number of layers and average number of carbon atoms per aromatic graphene are found to be varying from 7 to 8 and 16-21 for the coal samples with carbon content of 72- 77.4%. A good linear relationship exists between number of layers and stacking height of the aromatic lamellae in coal. 2012 by ESG. -
Study of State-of-the-Art Performance Metrics in NLP: Specifically for Text Summarization in the Medical Domain Using the SumPubMed Dataset
Text summarization is becoming very important given the number of documents produced each year across domains. In this paper we explore the various traditional metrics for text summarization, such as ROUGE, BLEU, METEOR, etc., and look at improving the performance of the existing metric by taking the stateof-the-art untrained metric SUPERT, and clubbing it with a readability score and a penalty for long summaries. The SUMPUBMED dataset was used for this research and a BERT extractive summarizer was used for generating the summaries. It was found that using a readability score with an unsupervised metric such as SUPERT helped in assessing the quality of the summary more accurately than earlier metrics. We compared the metrics such as SUPERT scores and BERT scores with and without involving the human annotated summaries in the SUMPUBMED dataset and found that untrained metrics perform better than when involving a reference annotated summary. 2025 Scrivener Publishing LLC. -
Study of surface wave velocity in distinct rheological models with flexoelectric effect in piezoelectric aluminium nitride structure
This study investigates the propagation of surface seismic waves at the loosely bonded interface of a visco-piezoelectric composite structure, incorporating the flexoelectric effect. The structure consists of a viscoelastic layer placed over a piezoelectric substrate, with the upper layer's shear stiffness modelled using the KelvinVoigt approach. An analytical method based on the separation of variables is employed to derive the complex dispersion relations for both electrically open- and short-circuit boundary conditions. Numerical simulations reveal the significant influence of various parameters on the wave's phase velocity and attenuation coefficient. Furthermore, a graphical comparison of three rheological modelsMaxwell, Newton, and KelvinVoigtis presented. The results show that the attenuation is lower in the Maxwell and Newton models compared to the KelvinVoigt model. Key findings include the bonding parameter's direct proportionality with phase velocity and inverse relationship with attenuation, and the pronounced impact of flexoelectricity on both phase velocity and attenuation. This theoretical framework offers insights into the piezo-flexoelectric coupling, with potential applications in designing sensors, actuators, energy harvesters, and nano-electronic devices. The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2024. -
Study of surface wave velocity in distinct rheological models with flexoelectric effect in piezoelectric aluminium nitride structure
This study investigates the propagation of surface seismic waves at the loosely bonded interface of a visco-piezoelectric composite structure, incorporating the flexoelectric effect. The structure consists of a viscoelastic layer placed over a piezoelectric substrate, with the upper layer's shear stiffness modelled using the KelvinVoigt approach. An analytical method based on the separation of variables is employed to derive the complex dispersion relations for both electrically open- and short-circuit boundary conditions. Numerical simulations reveal the significant influence of various parameters on the wave's phase velocity and attenuation coefficient. Furthermore, a graphical comparison of three rheological modelsMaxwell, Newton, and KelvinVoigtis presented. The results show that the attenuation is lower in the Maxwell and Newton models compared to the KelvinVoigt model. Key findings include the bonding parameter's direct proportionality with phase velocity and inverse relationship with attenuation, and the pronounced impact of flexoelectricity on both phase velocity and attenuation. This theoretical framework offers insights into the piezo-flexoelectric coupling, with potential applications in designing sensors, actuators, energy harvesters, and nano-electronic devices. The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2024. -
Study of Surface Waves Transmission in Orthotropic Bilateral Structure
This research work depicts the study of transmission of surface Rayleigh elastic waves in orthotropic layer having corrugated boundary resting over a pre-stressed orthotropic substrate. As a result, this study is made to spot the Rayleigh elastic wave transference under the consequence of initial stress in orthotropic material medium. Consequence of corrugation parameter, layer width parameter, initial stress parameter and density parameter on Rayleigh elastic wave propagation are marked separately. Distinguished parametric graphs are drawn following numerically the analytical study to exhibit the influence of distinct considered parameters on Rayleigh wave phase velocity of propagation. Frequency equations are obtained in closed determinant form under certain boundary conditions. Some particular cases have been deduced. Parametric results on the phase velocities yield a significant conclusion of which some are: (a) The corrugation parameter affects the more on phase velocity in comparison to initial stress (b) The orthotropic height stiffening can monotonically decrease the speed of phase. The present models may be applicable in engineering composites and for seismologist. 2023, The Author(s), under exclusive licence to Springer Nature India Private Limited. -
Study of the Balmer Decrements for Galactic Classical Be Stars Using the Himalayan Chandra Telescope of India
In a recent study, Banerjee et al. (2021) produced an atlas of all major emission lines found in a large sample of 115 Galactic field Be stars using the 2-m Himalayan Chandra Telescope (HCT) facility located at Ladakh, India. This paper presents our further exploration of these stars to estimate the electron density in their discs. Our study using Balmer decrement values indicate that their discs are generally optically thick in nature with electron density (ne) in their circumstellar envelopes (CEs) being in excess of 1013 cm-3 for around 65% of the stars. For another 19% stars, the average ne in their discs probably range between 1012 cm-3 and 1013 cm-3. We noticed that the nature of the H? and H? line profiles might not influence the observed Balmer decrement values (i.e. D34 and D54) of the sample of stars. Interestingly, we also found that around 50% of the Be stars displaying D34 greater than 2.7 are of earlier spectral types, i.e. within B0B3. 2024 Societe Royale des Sciences de Liege. All rights reserved. -
STUDY OF THE LINEAR AND NONLINEAR REGIMES OF NATURAL CONVECTION WITH WEAK OR DOMINATING INTERNAL HEAT GENERATION FOR RIGID-FREE BOUNDARIES
The paper presents the linear and non-linear regimes of natural convection in the presence of uniform internal heat generation for rigid-free boundaries. A linear stability analysis followed by nonlinear stability analysis is carried out for using a novel procedure. The eigenvalue of the two problems are different. The first one has Rayleigh number based on internal heat generation as the eigenvalue while the second, which is of the classical Bard type, has a buoyancyRayleigh number. The critical Rayleigh number in both problems is initially determined using the single-term Galerkin method, followed by a refinement of the value by the Maclaurin series method. The findings indicate that the system becomes stable with increasing values of the porous parameter and the Brinkman number. The percentage relative error in the eigenvalue obtained by the single-term Galerkin method relative to that obtained by the Maclaurin series method is presented. In the second natural convection problem, we have two Rayleigh numbers, viz., the weak internal Rayleigh number, RI, and the external Rayleigh number, Ra. The effect of RI on Rac is to reduce it in the case of a heat source and increase it in the case a of heat sink. Additionally, conditions facilitating the transition from Brinkman Bard convection to DarcyBard convection are presented. The GinzburgLandau equation is obtained for both the problems and the scaled Lorenz model is derived in the case of second problem. The solution from the GinzburgLandau equation is used to plot for the amplitude and results are illustrated. 2025 by Begell House,. -
Study of the personal factors influencing voluntary turnover amongst women
In a country where the economic and social independence of a woman is dependent on the way households are structured and organised, the rise in their education and decline in their workforce participation rate is an indication of their paradoxical situation. In this study we evaluate the direct effect of the factors in the personal domain of women on her career break decision. The data from 402 Indian women was analysed using Exploratory Factor Analysis and Confirmatory Factor Analysis, which was then followed by Structural Equation Modelling to check the conceptual model developed through literature review. In present study support personal predictors to turnover intention outcome model, confirming the influence of role conflict, role expectation, role perception, stress, financial soundness, role overload and guilt. Role perception and expectation of women were most significant factors influencing turnover intention of women, implying that the most important change needed is for a change in their own mindset and those around them to arrest their exit from the workforce. 2021 Ecological Society of India. All rights reserved. -
Study of the structural, optical, electrical and electrochemical properties of copper oxide thin films synthesized by spray pyrolysis
In our present study we focus on characterizing copper oxide (CuO) thin films synthesized at various substrate temperatures and to assess the electrochemical performance of the optimized sample. The spray pyrolysis method was used to fabricate CuO thin film samples, with the substrate temperatures ranging from 250 to 400C. The coatings underwent characterization through different analytical techniques, including X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, Raman spectroscopy, and Hall effect measurements. All the thin film samples were confirmed to have a monoclinic phase. The presence of Cu=O was confirmed by Raman spectroscopy. All the samples exhibited P type conductivity except the one synthesized at 400C. Galvanostatic chargedischarge studies revealed a pseudocapacitive nature for the optimized sample synthesized at 350C. The symmetrical charging and discharging curves imply excellent material reversibility, indicating long-term cyclic stability. The Nyquist plot exhibited a semicircle at high frequencies, representing the materials intrinsic resistance and a linear behavior at low frequencies, depicting the ion transfer resistance. The electrode demonstrated favorable electrochemical properties and potential use of the material in supercapacitor applications. 2024, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature. -
Study of transient nature of classical Be stars using multi-epoch optical spectroscopy
Variability is a commonly observed property of classical Be stars (CBe) stars. In extreme cases, complete disappearance of the H? emission line occurs, indicating a disc-less state in CBe stars. The disc-loss and reappearing phases can be identified by studying the H? line profiles of CBe stars on a regular basis. In this paper, we present the study of a set of selected nine bright CBe stars, in the wavelength range of 62006700 to better understand their disc transient nature through continuous monitoring of their H? line profile variations for five consecutive years (20152019). Based on our observations, we suggest that four of the program stars (HD 4180, HD 142926, HD 164447 and HD 171780) are possibly undergoing disc-loss episodes, whereas one other star (HD 23302) might be passing through disc formation phase. The remaining four stars (HD 237056, HD 33357, HD 38708 and HD 60855) have shown signs of hosting a stable disc in recent epochs. Through visual inspection of the overall variation observed in the H? EW for these stars, we classified them into groups of growing, stable and dissipating discs, respectively. Moreover, our comparative analysis using the BeSS database points out that the star HD 60855 has passed through a disc-less episode in 2008, with its disc formation happening probably over a timescale of only two months, between January and March 2008. 2022, Indian Academy of Sciences. -
Study of Transport Characteristics using Impedance Spectroscopy and Memristor Property Analysis of Protonated Polyaniline-WO3 Nanocomposite
Polyaniline-WO3 nanocomposite was synthesized through in-situ chemical polymerization. The structural properties are studied by using XRD and FESEM characterization. The XRD results confirmed the presence of crystalline WO3 nanoparticles in the polymer nanocomposite structure. FESEM images confirmed the sheet-like structure with heterojunction of WO3 nanoparticles and polyaniline matrix. The transport properties of the synthesized nanocomposites are studied using impedance spectroscopy analysis. The complex impedance analysis conducted using the Nyquist plot and equivalent circuit model of the nanocomposites are simulated using ZSimpWin software. The major conduction mechanism in the material is found to be grain boundary effect and the grain boundary conduction parameters are calculated. The polyaniline-WO3 nanocomposite with WO3 doping concentration of 15% has exhibited better sensing characteristics towards the target VOC (Volatile Organic Compound) 3-Carene, a breath-based biomarker for malaria. The memristor sensor model of the polyaniline nanocomposite with 15% of WO3 is simulated using MATLAB-Simulink. The pinched hysteresis loop obtained confirmed the memristor properties of the material. 2022, Universiti Malaysia Perlis. All rights reserved. -
Study of vibrations in smart materials semiconductor under differential imperfect contact mechanism and nanoscale effect with electromechanical coupling effect
The work focuses on the transference of Love-type waves which are surface seismic waves that cause horizontal displacement perpendicular to the direction of propagation, in a multiferroic solid cylindrical structure, where the interface is assumed to be imperfect and made of a magneto-electro-elastic (MEE) structure. The analytical solution for the layer is obtained using the spatially variable quasi-classical technique which approximates complicated differential equations while maintaining their key physical properties. The coefficients of waves phase velocities and attenuation are greatly affected by different parameters as shown in the numerical example. In addition, a graphical comparison of electrical, magnetic, mechanical, magneto-mechanical, electromechanical, and magneto-electrical imperfections in electrically and magnetically open and short cases is presented. The phase velocity is higher in the electrically and magnetically open case as compared to the short case as shown in the results. Some major outcomes are summarized here: the bonding parameter is highly proportional to the phase velocity and inversely proportional to the attenuation coefficient, and imperfection parameters have a serious influence on the curve of phase velocity and attenuation coefficient. This theoretical study leads to the understanding of piezoelectric and piezomagnetic coupling and its potential application and design to sensors, actuators, energy harvesters, and nano-electronics. The novelty lies in the adoption of the quasi-classical method to approach solving differential equations using a polar coordinate system for the first time. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature 2025. -
Study of X-Ray Intraday Variability of HBL Blazars Based on Observations Obtained with XMM-Newton
We present an extensive study on the X-ray intraday variability of 10 teraelectronvolt-emitting high synchrotron peaked blazars (HBLs): 1ES 0229+200, 1ES 0414+009, PKS 0548-322, 1ES 1101-232, 1H 1219+301, H 1426+428, Mrk 501, 1ES 1959+650, PKS 2005-489, and 1ES 2344+514 made with 25 XMM-Newton pointed observations during its operational period. Intraday variability has been estimated in three energy bands: soft (0.3-2 keV), hard (2-10 keV), and total (0.3-10 keV). Although seven out of 10 teraelectronvolt HBLs exhibited some intraday variability at 3? levels, no major variations exceeding 6% were detected. We explored the spectral properties of the sample by extracting the hardness ratio from the soft and hard bands; no significant variations in the hardness ratio were observed in any source. We performed power spectral density analyses on the variable light curves by fitting power laws, yielding slopes lying in the range of 1.11-2.93 for different HBLs. We briefly discuss possible emission mechanisms and carry out rough estimates for magnetic fields, electron Lorentz factors, and emission region sizes for seven of these HBLs. 2022. The Author(s). Published by the American Astronomical Society. -
Study on 5G Massive MIMO Technology Key Parameters for Spectral Efficiency Improvement Including SINR Mapping on Rural Area Test Case
Massive MIMO is one of the key disruptive technologies in 5G which offers significant change in the core network architecture and channel modeling compared to the previous wireless communication standards. There are many research works currently focusing on implementing Massive MIMO network in different channel propagation models. ITU, 3GPP and IMT consortium deliver timely 5G LTE releases and taken as benchmark documents by various telecom companies and universities to set up testing, trials and hardware deployments. However, without optimization on spectral efficiency parameter, the specifications proposed by 5G in terms of improvement in data rate or throughput could be difficult to achieve. This paper initially provides an in-depth study on spectral efficiency estimation and optimization in Massive MIMO by investigating different research papers. From these papers, list of parameters involved in spectral efficiency are identified, such as, fading characteristics, power or energy efficient parameters, standard deviation, angle of arrival factors in antennas installed in base stations and many others. The author however concludes with the best selection of constraint optimization parameters to improve the spectral efficiency taking into account of its simple design and major impact on the improvement in the result by taking downlink scenario of a simulation environment using 5G Massive MIMO network. SINR mapping of standard Rural Macro test scenario adopted from M 2314, LTE release 17 of 5G framework is simulated in this research paper. 2022 IEEE.