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Three-component p-TSA catalyzed synthesis of hydrazinyl thiazole derivatives
A direct single-pot three-component procedure for synthesizing bio-active hydrazinyl thiazole derivatives has been demonstrated. The reaction involves substituted 2-Bromoacetophenones, carboxaldehydes, and thiosemicarbazide to form the hydrazinyl thiazole scaffolds via a simple condensation reaction followed by intramolecular cyclization with p-TSA as a catalyst at room temperature. The ease of product separation, lack of column chromatographic purification, and use of readily available starting materials result in an efficient approach for organic synthesis. 2023 Elsevier Ltd. All rights reserved. -
Three-Component Convection in a Vertically Oscillating Oldroyd-B Fluid With Cross Effects
This paper sheds light on the impact of vertical oscillations (or gravity modulation) on triple-diffusive convection in a viscoelastic fluid using the Oldroyd-B model, in the presence of cross effects. Cross effects can significantly impact three-component convective systems, despite having small magnitudes. When the cross terms, indicating coupled molecular cross-diffusion of the mixture components, are included in the equations governing heat and species transport, then a deviation from the usual three-component convection process is observed. An analytical solution has been found using linear and nonlinear analysis. The conditions for the onset of convection have been obtained using the linear analysis, which is based on the perturbation technique and the Venezian method. In nonlinear analysis, the expressions for Nusselt and Sherwood numbers, which quantify the rate of heat and mass transport respectively, are obtained by deriving the Lorenz model. It has been found that the onset of convection and heat and mass transport can be controlled by choosing the appropriate values of the parameters. 2022, The Author(s), under exclusive licence to Springer Nature B.V. -
Three dimensional mixed convection flow of hybrid casson nanofluid past a non-linear stretching surface: A modified Buongiorno's model aspects
The purpose of this study is to determine the role of mixed convection, Brownian motion, and thermophoresis in the dynamics of Casson hybrid nanofluid in a bidirectional nonlinear stretching sheet. For the flow model, a combination of Tiwari and Das models, as well as Buongiornos model, is considered. The thermophysical characteristics of Gr, TiO2, and blood are employed. With the assistance of relevant similarity transformation, the describing flow equations of a Casson hybrid nanofluid model are reformed in the form of a system with a single independent variable. The solution for these equations is obtained using the RKF-45 approach. The velocity, temperature, and concentration fields are visually developed for both linear and non-linear stretching sheets, and the implications of the major parameters are presented in detail. It is clear from the current investigation that heat and mass transfer characteristics of fluid are better in the case of linear stretching than non-linear stretching. Furthermore, the mixed convection parameter is found to enhance the fluid flow velocity. However, the trend is quite opposite in the thermal and concentration fields. Meanwhile, the increase in the yield stress caused due to the rise in the Casson parameter decreases the flow velocity. 2021 Elsevier Ltd -
Three decades of advances in extraction and analytical techniques for guava (Psidium guajava L.): A review
Despite extensive experimental focus, there remains a notable gap in comprehending the progressive development of these techniques over time. This comprehensive review is dedicated to cataloging the evolution of extraction and analytical methods spanning several decades. In this article, we meticulously traced the development of analytical and extraction techniques. Additionally, we intricately map the periodic discovery of metabolites within guava fruit, aligning them with the chronological utilization of analytical methods. This article results from extensive research and literature analysis to bridge the knowledge gap. Our efforts highlight the advantageous phytochemicals in guava and the diverse extraction techniques available. By encompassing various facets of analytical methods and delving into metabolomics, this review can offer substantial benefits to cultivating future guava varieties. Subsequent sections within this review will serve as a valuable resource, aiding prospective researchers in identifying the most effective extraction and analytical methods for discovering novel metabolites in guava or similar biological samples. Furthermore, through a comprehensive timeline detailing methodological advancements, this review enhances our understanding of the evolutionary path of guava research. Such insights empower researchers to make informed decisions and actively contribute to the continual advancement of the field of research. 2024 -
Threats and security issues in smart city devices
The main objective of this chapter is to discuss various security and privacy issues in smart cities. The development of smart cities involves both the private and public sectors. The theoretical background is also discussed in future growth of smart city devices. Thus, the literature survey part discusses different smart devices and their working principle is elaborated. Cyber security and internet security play a major role in smart cities. The primary solution of smart city security issues is to find some encryption methods. The symmetric and asymmetric encryption algorithm is analyzed and given some comparative statement. The final section discusses some possible ways to solve smart city security issues. This chapter showcases the security issues and solutions for smart city devices. 2022, IGI Global. -
Threat Intelligence Model to Secure IoT Based Body Area Network and Prosthetic Sensors
This research work proposes a threat intelligence model for Internet-of-Things (IoT) sensors-based Body Area Network (BAN). It is focused primarily to be used in healthcare monitoring of vital parameters of critically ill patients and on the contrary performance measurement system for healthy sportspersons. The end-point control based applications are growing enormously with the advent of IoT based sensors and actuators being used in intelligent real-time systems. At the same time, it is expected to keep the ecosystem safe for the user while delivering the constant updates. However, the process for the monitoring health and wellness parameters of a patient, or measuring endurance and performance of a sportsperson, it remains vulnerable without a secure environment. Using the proposed model, the entire healthcare ecosystem may be designed for the personalized medication of a patient who are using sophisticated life-saving device like prosthetic heart valve or an elderly person dependent on medical-aided ambulatory devices or a sportsperson on performance measurement system. The Electrochemical Society -
Thinking Beyond Empowerment : Understanding Autonomy in the Context of Kudumbashree
The concepts empowerment, agency and autonomy have gained a wider range of attention in newlinethe developmental research regimes. Amidst the conceptual drift these concepts are used newlineinterchangeably leading to uncertainty and proliferated meanings. The process of newlineempowerment may not always lead to autonomy. Through an ethnography of Kudumbashree, newlinean SHG in the South Indian state of Kerala, the current research focuses on how these women exercise agency to trouble the conventional boundaries between empowerment and autonomy. The transition of agency from the economic to the political domain is a subtle enterprise and is mediated by a number of factors including economic independence, decision making capability, mobility and political participation. Social - economic - political and cultural implications of women empowerment could be the first step in challenging and overcoming the relations of oppression in any society. The stereotypical assumptions can be negotiated by solely apportioning responsibilities and re-engaging with the system through everyday practices. The nuances of empowered women s re-engagement with local power regimes lead newlineto changes at the conceptual level that cuts beyond the individual and group level material transformations. The study figures how autonomy is a mediated process that is both agentic and subversive to the local patriarchal structures. -
Thickness dependent tungsten trioxide thin films deposited using DC magnetron sputtering for electrochromic applications
DC magnetron sputtering was used to grow tungsten oxide (WO3) thin films on FTO and corning substrates. SEM, XRD, Electrochemical Analyzer, and UVVis Spectrometer were used to analyze surface morphology, structural properties, electrochromic characteristics, and optical characteristics. At an 800 nm wavelength, a decrease in thin-film thickness increased optical transmittance from 87 % to 95 %. Furthermore, coloring efficiency was observed to vary with the thickness of thin films for both 500 nm and 375 nm are 10.34 cm2 C-1 to 18.57 cm2 C-1. In comparison to the high-thickness thin film, the lesser-thickness deposited nano-thin film has a higher diffusion coefficient. At 8 10-4 mbar partial pressure, the diffusion coefficients for the smaller and the high-thickness thin film are 7.28x10-14 cm2s?1 and 6.0x10-14 cm2s?1, respectively. The diffusion coefficient and coloring efficiency have been found to have a considerable influence on the thickness and surface-to-volume ratio, which could be important in electrochromic applications. 2022 -
Thermorheological effect on RayleighBard magnetoconvection in a biviscous Bingham fluid with rough boundary condition on velocity and Robin boundary condition on temperature
The thermorheological effect on the onset of RayleighBard convection in a biviscous Bingham fluid in the presence of a horizontal magnetic field is investigated considering rough boundary conditions on velocity and Robin boundary conditions on temperature. The viscosity of the electrically conducting fluid is assumed to be sensitive to temperature variation. Linear and global nonlinear stability analyses are performed using the Chebyshev pseudospectral method to determine the existence of instability or otherwise. A general interpretation is made from the results to show the effects of the magnetic field and the variable viscosity on the system's stability. The biviscous Bingham parameter and the Chandrasekhar number are shown to have a delay in the onset of convection, while the effect of temperature sensitivity is to advance the onset. It is found that the results of linear and global nonlinear stability are not in agreement, so the region of subcritical instability exists. Also, the results obtained for RayleighBard convection agree pretty well with those of Platten and Legros and Siddheshwar et al. for the limiting cases. 2023 Wiley Periodicals LLC. -
Thermorheological and magnetorheological effects on Marangoni-Ferroconvection with internal heat generation
Marangoni convectiveinstability in a ferromagnetic fluid layer in the presence of a spatial heat sourceand viscosity variation is examined by means of the classical linear stability analysis. The higher order Rayleigh-Ritz technique is used to compute the critical Marangoni number. The effective viscosity of the ferromagnetic liquid is taken to be a quadratic function of both the temperature and magnetic field strength. It is shown that the ferromagnetic fluid is significantly influenced by the effect of viscosity variation and is more prone to instability in the presence of heat source compared to that when viscosity is constant. On comparing the corresponding results of heat source and heat sink it is found that heat sink works in tandem with the effect of viscosity variation if magnetic field dependence of viscosity dominates over temperature dependence. If the temperature dependence of viscosity dominates, the effects of viscosity variation and heat sink are mutually antagonistic. Published under licence by IOP Publishing Ltd. -
Thermomechanical and viscoelastic properties of biodegradable and biocompatible polymer nanocomposites
Due to the ongoing depletion of fossil fuels, which have been the primary sources of monomers from which the vast majority of synthetic polymers are derived, biodegradable and biocompatible polymeric composites (BBPCs) have received a great deal of attention in recent years. The use of biodegradable and biocompatible polymers is expanding due to their ability to reduce toxic and nondegradable waste materials. Traditional polymers such as polypropylene, polyethylene, and polystyrene are nonbiodegradable, making reuse and recycling difficult. As a result, massive amounts of nonbiodegradable waste are generated all over the world. Biodegradable polymers have been widely used in medical and packaging applications because they are typically made from renewable materials that biodegrade when discarded. Producing biodegradable composites with the addition of environmentally friendly nanofillers is increasingly being regarded as the next-generation materials for improving some of the properties and performance of biodegradable polymers. Despite growing interest in biodegradable and biocompatible polymer research, most studies focus on their preparation methodologies and characterization, with little attention paid to their thermo-mechanical and viscoelastic behavior. Thus, the potential of biodegradable and biocompatible polymer nanocomposites under various thermo-mechanical conditions, as well as their viscoelastic behavior, is reviewed in this chapter. 2023 Elsevier Inc. All rights reserved. -
Thermoluminescence glow curve analysis and trap parameters calculation of UV-induced La2Zr2O7 phosphor doped with gadolinium
Thermoluminescence (TL) glow curve analysis and calculation of trap parameters are reported for gadolinium (Gd3+)-doped La2Zr2O7 (LZO) phosphor. Phosphors were prepared by modified solid-state reaction method with varying concentration of Gd3+ (0.12.5mol%) including proper calcination and sintering temperature. Structural analysis of prepared phosphor for optimized TL concentration was recorded by X-ray diffraction analysis technique. Morphology was analyzed by scanning electron microscopic technique. The UV ray induced to the phosphor and effect of dose response recorded for variable dose rates of UV and TL glow curve were observed. The experimental and theoretical comparison was done by computerized glow curve deconvolution technique which determines the trap parameters such as trap depth, order of kinetics, and frequency factor for optimized concentration of dopant. The trap parameters and trap model are discussed in detail. 2019, Springer Science+Business Media, LLC, part of Springer Nature. -
Thermoelectric effects in graphene
Graphene, owing to its unique electronic properties, has become one of the active areas of condensed matter research with promising applications in future efficient thermoelectric (TE) and energy storage devices. The present work reviews the status of thermoelectric power (TEP) of graphene systems, including single-layer, bilayer, and nanoribbons. The theory of TEP, based on the Boltzmann transport formalism in 2D systems, is given. An analysis of the experimental data, in terms of the diffusion and the phonon-drag contributions to TEP, with regard to the various scattering mechanisms operative in graphene systems, is presented. The outlook on TEP for better understanding of the TE properties of graphene is discussed. 2016 by Taylor and Francis Group, LLC. -
Thermoelectric effects in graphene
Graphene, owing to its unique electronic properties, has become one of the active areas of condensed matter research with promising applications in future efficient thermoelectric (TE) and energy storage devices. The present work reviews the status of thermoelectric power (TEP) of graphene systems, including single-layer, bilayer, and nanoribbons. The theory of TEP, based on the Boltzmann transport formalism in 2D systems, is given. An analysis of the experimental data, in terms of the diffusion and the phonon-drag contributions to TEP, with regard to the various scattering mechanisms operative in graphene systems, is presented. The outlook on TEP for better understanding of the TE properties of graphene is discussed. 2016 by Taylor & Francis Group, LLC. All rights reserved. -
Thermoconvective instability in a vertically oscillating horizontal ferrofluid layer with variable viscosity
The paper sheds light on the linear and nonlinear stability of a ferrofluid with the temperature and magnetic-field-dependent viscosity subjected to an imposed time-periodic gravity modulation. The perturbations in the system due to external reasons are expanded in terms of the amplitude of modulation in the case of linear stability and a truncated representation of the Fourier series in the case of nonlinear stability. A nonautonomous Lorenz model for the problem is first obtained, and both linear and nonlinear analyses of the system are performed using this. The expression for the critical Rayleigh number, (Formula presented.), and the correction Rayleigh number, (Formula presented.), is found from the linearized Lorenz model. The Lorenz system of equations is solved for the amplitude to arrive at the Nusselt number (Nu), which quantifies the heat transport. In the study we find that the thermorheological effect and the magnetization effect work in unison to destabilize the system, while the magnetorheological effect and the effect of vertical oscillations stabilize the system. The influence of the parameters on the heat transport is the opposite to their effect on the critical Rayleigh number. The results of the paper agree quite well with those of limiting cases. 2020 Wiley Periodicals LLC -
Thermo-solutal Marangoni convective assisting/resisting flow of a nanofluid with radiative heat flux: A model with heat transfer optimization
The mixed Marangoni assisting/resisting flow of a nanofluid with thermal radiative heat flux is analyzed when thermal and solutal buoyant forces are significant. The heat and mass transfer rates are simultaneously optimized by utilizing the Response Surface Methodology (RSM). The face-centered Central Composite Design (fc-CCD) is used for the numerical experimental design involved in RSM. The sensitivities of the heat and mass transfer rates are evaluated to compare the impact of the thermal and solutal buoyant forces. Appropriate scaling and similarity transformations are utilized to simplify the problem and then numerical solutions are obtained. The nanoliquid flow, temperature, and concentration profiles are plotted for the buoyancy assisting and opposing Marangoni cases. The Marangoni flow with opposite buoyancy is found to have a greater magnitude of velocity while the flows assisted by the buoyancy have a greater magnitude of temperature and concentration profiles. Thermal buoyancy force has a predominant (0.6%) impact on both heat and mass transfer rates compared to solutal buoyancy force. Buoyancy forces are positively sensitive to heat and mass transfer rates. The thermal radiation aspect augments the temperature profile throughout the domain. The optimized mass and heat transfer rates ((Formula presented.) and (Formula presented.)) is achieved at the highest level of the buoyancy forces and ratio of Marangoni numbers. 2022 Wiley-VCH GmbH. -
Thermal, mechanical and ?-ray shielding properties of micro- and nano-Ta2O5 loaded DGEBA epoxy resin composites
In this work, we have investigated the synergistic effect of micro- and nano-Ta2O5 fillers in the epoxy matrix on the thermal, mechanical, and radioprotective properties of the composites. Morphological analysis revealed uniform dispersion of fillers in the matrix. Both the thermal stability and tensile properties of matrices have enhanced in the presence of fillers. Although the nanocomposites showed significantly higher tensile strength and Youngs modulus compared to micro-composites, the enhancement in these properties was predominant at low loadings. Dynamic mechanical analysis indicated good interfacial adhesion and positive reinforcing effect on the matrix even at higher loading (30 wt%) of nano-Ta2O5. ?-Ray attenuation studies performed in the energy range of 0.3561.332 MeV revealed better ?-ray shielding ability of nanocomposites compared to microcomposites at same weight fraction of fillers. In particular, ?-ray attenuation at 0.356 MeV for 30 wt% nano-Ta2O5 loaded epoxy composite was enhanced by around 13% compared to the microcomposite at the same loading. Increased surface-to-volume ratio of nanofillers and consequent increase in matrix-filler adhesion and radiation-matter interaction have manifested in an overall enhancement in the thermal, mechanical, dynamic mechanical, and radiation shielding characteristics of nano-Ta2O5/epoxy composites, proving them as promising ?-ray shields. 2021 Wiley Periodicals LLC. -
Thermal Studies of Multiwalled Carbon Nanotube Reinforced with Silicone Elastomer Nanocomposites
This article studies the enhancement in the properties of silicon elastomer (SiR) reinforced by multiwalled carbon nanotube (MWCNT). Multiwalled carbon nanotube filled silicone rubber composites were prepared. The effects of loading levels of MWCNT on the thermal properties of silicone elastomer were investigated. SEM studies reveal the smooth distribution of MWCNT in silicon matrix. At higher concentration nanoparticles collapse together to form agglomerates. The high resolution transmission electron microscopy (HR-TEM) photographs shows excellent/homogeneous distribution of MWCNT in silicon matrix and agglomeration occurs at higher concentrations. Thermal properties of nanocomposites have been characterized using differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA). The transition temperature appears at below -25C for MWCNT reinforced SiR nanocomposites. TGA thermogram, shows that temperature at 10%, 20%, 30%, and 50% weight loss for SiR nanocomposites is higher than as compared to unfilled SiR. The results indicate that the addition of MWCNT significantly enhanced the thermal stability of silicon elastomer. 2018 Elsevier Ltd. -
Thermal optimisation through the stratified bioconvective jetflow of nanofluid
Bioconvection is a fascinating phenomenon observed in various biological systems, where the motion of motile microorganisms generates fluid flow patterns. This article explores the occurrence and characteristics of bioconvection within the context of a jet flow. The study of bioconvection in jet flow involves the interaction between motile microorganisms and the fluid dynamics of the surrounding medium. Microorganisms such as bacteria and algae are known to exhibit directed swimming behavior, which can lead to the formation of dynamic flow structures. Investigating the mechanisms underlying bioconvection in jet flow requires a multidisciplinary approach encompassing fluid dynamics, microbial ecology, and mathematical modeling. Experimental techniques, such as microscopy and particle image velocimetry, along with computational simulations, are employed to analyze the complex interactions between microorganisms and the fluid flow. In this regard, a supportive mathematical model is designed using partial differential equations (PDEs) which are later transformed into ordinary differential equations using similarity transformations. The resulting system of equations is solved using the RKF-45 method and the outcomes are recorded in tables and graphs. The consideration of thermophoresis has shown a significant impact on the heat and mass transfer of the jet flow and both these profiles are observed to increase with thermophoresis. Meanwhile, the Schmidt number decrease their respective mass profiles. Furthermore, the porosity is found to create a drag force which tends to oppose the fluid flow. 2023 Taylor & Francis Group, LLC. -
Thermal optimisation through multilayer convective flow of CuO- MWCNT hybrid nanofluid in a composite porous annulus
The present article deals with the analysis of the three-layer convective flow of immiscible nanofluids in a composite porous annulus. Water and kerosene are chosen as base fluids due to their immiscible property that leads to the formation of a non-physical boundary separation and thus forming a multi-layer flow. In this model, the hybrid nanofluid is formed by suspending copper oxide (CuO) and multi walled carbon nanotubes (MWCNTs) in water which is sandwiched between layers of nanofluid formed by suspending CuO in kerosene leading to two boundary separations that give rise to the interface regions. Such a flow finds applications in the field of solar reactors, electronic cooling, etc. The model based on the above assumptions is in the form of a system of ordinary differential equations that are solved using the differential transformation method. The solutions are found to be in agreement with the existing literature and the results of this study are interpreted graphically. It is to be noted that the interfacial region in the multilayer nanofluid flow helps in maintaining the system at an optimum temperature which helps to cool down the systems. Further, the increase in the Eckert number increases the heat conduction of the nanofluid and pressure enhances the flow speed of the nanofluid. 2022 Informa UK Limited, trading as Taylor & Francis Group.