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Thermal fatigue characteristics of 8Y2O3-ZrO2, La2Zr2O7, La2(Zr0.7Ce0.3)2O7 and La2Ce2O7 thermal barrier coatings in duplex, multilayer functionally graded and multilayer configurations
La2Zr2O7, La2(Zr0.7Ce0.3)2O7 and La2Ce2O7 pyrochlore plasma sprayable powders were synthesized and plasma spray coated on steel plates with NiCrAlY bond coat. Three different configurations were used: duplex, multilayer functionally graded and multilayer, with different combinations of commercial 8% yttria stabilized zirconia (8YSZ) and NiCrAlY (bond coat) layers. The prepared coatings were compared with the standard duplex 8YSZ thermal barrier coatings (TBCs) with a goal to study their suitability to serve as TBCs. TBCs layer thicknesses and interfaces were studied via SEM on polished cross section metallographic samples removed from the spray coated TBCs. Thermal fatigue resistance was evaluated by directing a gas flame on the ceramic surface at 1200 and 1400 C, followed by its rapid withdrawal and forced cooling by pedestal fan. The maximum number of thermal shock cycles the coatings could withstand before failure was determined. The multilayered TBCs with lanthanum cerate composition stacked with 8YSZ exhibited the superior thermal fatigue resistance characteristics compared to all other studied TBCs. The findings were correlated with the crystalline phases of the ceramic coatings, obtained via XRD, and discussed in the light of existing literature. 2023 University of Novi Sad, Faculty of Technology. All rights reserved. -
Thermal Marangoni convection in two-phase flow of dusty Casson fluid
This paper deals with the thermal Marangoni convection effects in magneto-Casson liquid flow through suspension of dust particles. The transpiration cooling aspect is accounted. The surface tension is assumed to be fluctuating linearly with temperature. The fluid and dust particle's temperature of the interface is chosen as a quadratic function of interface arc length. The governing problem is modelled by conservation laws of mass, momentum and energy for fluid and dust particle phase. Stretching transformation technique is utilized to form ordinary differential equations from the partial differential equations. Later, the numerical solutions based on Runge-Kutta-Fehlberg method are established. The momentum and heat transport distributions are focused on the outcome of distinct governing parameters. The results of Nusselt number is also presented and discussed. It is established that the heat transfer rate is higher in the case of dusty non-Newtonian fluid than dusty Newtonian fluid. The rate of heat transfer can be enhanced by suspending dust particles in a base liquid. 2017 -
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. -
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, 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. -
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. -
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 -
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. -
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. -
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-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. -
Through the Lens of Recession 2.0: Diversification Dynamics Between the Leading Asian Stock Markets
The focus of this article is to analyse the inter-linkages between eight leading stock markets in Asian continent from the period of July 2011 to February 2018. This period holds relevance as this was the time when Recession 2.0 set in, which adversely affected the developed economies; however, the developing economies withstood the crisis without much of an impact. Co-integration and Granger causality tests were conducted to probe the inter-linkages. Study revealed a positive impact on Asian stock market indices collectively on each of the indexes. The highest number of unidirectional causalities was to KOPSI and NIFTY from rest of the stock indices. Results confirmed that no co-integration relationship existed among the selected indices indicating favourable diversification opportunities. Thus, the study fosters global market participants and policymakers to consider the nitty-gritties of stock market integration so as to benefit from international stock market diversification in the Asian region. 2022 Management Development Institute. -
Through the Lenses of Sexual Minorities in the Indian LGBTQ + Community: Perception of Social Equality and Community Support
Whether in the form of same-sex attraction or love, the history of same-sex relationships has been well documented in every culture across the globe. In India, evidence of the same can be found on the monolithic sculptures of the Vishvanath Temple in Khajuraho and texts like Mahabharata and Sushrata Samahita. The acceptance and openness enjoyed by the non-hetero-normative and non-cis-gender individuals in ancient India, changed after the nations colonization. In current times, mainstream society holds heterosexual intercourse as the norm while considering same-sex relationships as deviations. Same sex relationships are a highly stigmatized and garner objections from several religious and political sects. This social stigma and erasure becomes harsher when directed toward individuals with polysexual or asexual orientations. The lack of awareness and representations garners bisexuals, pansexuals and asexuals the status of sexual minorities within the LGBTQ + community. This study makes use of three focus group discussions to explore the perception of each sexual minority regarding social equality within the Indian LGBTQ + community and outside it, alongside trying to understand the community support received by the sexual minorities in the Indian LGBTQ + community. The study uses inductive thematic analysis to draw out themes. The results indicate a predominant feeling of being misunderstood, exploited, fetishized and alienated even within the LGBTQ + community while finding solace in their own sub-communities and the online community. The results also reveal feelings expectations held by individuals from each sexual minority in terms of their desired place in society. 2024 Taylor & Francis Group, LLC. -
Time allocation between paid and unpaid work among men and women: An empirical study of indian villages
The paper examines the time allocation between paid work (wage earning or self-em-ployed work generally termed as employment work) and unpaid (domestic chores/care work generally termed as non-employment work) along with wage rates, imputed earnings, and occupational structure among men and women and according to different social groups to establish the extent to which the rural labour market is discriminated by sex and social group. The major objective of the paper is to show the differential in wage income between men and women in farm and non-farm activities. The paper also shows the division of time between employment and non-employ-ment activities by men and women. The paper uses high-frequency data and applies econometric techniques to know the factors behind time allocation among different activities across gender. The study finds that males spend more hours on employment work and work at a higher wage rate than females. As a result, a vast monetary income gap between men and women is observed, even though women worked more hours if employment and non-employment activities are jointly taken into consideration. Time spent on employment work and non-employment (mainly domestic chores) has been found to vary significantly due to social identity, household wealth, land, income, educa-tion, and skill. The segregation of labour market by sex was evident in this study, with men shifting to non-farm occupations with greater monetary returns and continued dependence on womens farm activities. Enhancing the ownership of land and other assets, encouraging womens participation particularly among minorities, and improving health are some of the policy recommendations directed from this study to enhance participation in employment work and shifting towards higher wage income employment. 2021 by the authors. Licensee MDPI, Basel, Switzerland. -
Time Efficient Hash Key Generation for Blockchain Enabled Framework
Blockchain, in general, helps organizations to improve the transparency and governance by removing its shortfalls and building better control overall. Blockchain network, public or private, is a competent technology when used in order with an optimized hashing technique. In a blockchain network, one of the common issues is performance while registering any transactions. Blockchain must need to do some preliminary checks to avoid double-spending before registering the transaction. Here, we implement one of the optimization aspects of the hashing technique, which can contribute to the blockchain mining processes and save time. It enables the blockchain to perform efficiently and reliably. In addition, we examine how well different hashing algorithms perform when added to the blockchain network's processes. In this research, we analyze several hashing techniques that are employed in the blockchain and are also applied in the supply chain domain due to their efficacy in mitigating past attacks. Our proposed hashing technique allows a blockchain network to improve security and its overall processes. The proposed hashing technique achieves approx. 10-90% performance gain improvements over other existing technique. Our proposed hashing technique allows a blockchain network to improve security and its overall processes. The study also examines how the supply chain management contributes in increasing of overall lead time where process optimization or technological enhancement plays key roles in minimizing the time of some or all the processes. Lead time is one of the common issues of supply chain which impacts on overall order delivery time. We address on how the conjunction of blockchain with optimized hashing technique can address supply chain lead time issues. 2013 IEEE. -
Time resolved spectroscopy of a GRS 1915 + 105 flare during its unusual low state using AstroSat
Since its disco v ery in 1992, GRS 1915 + 105 has been among the brightest sources in the X-ray sky. Ho we ver, in early 2018, it dimmed significantly and has stayed in this faint state ever since. We report on AstroSat and NuSTAR observation of GRS 1915 + 105 in its unusual low/hard state during 2019 May. We performed time-resolved spectroscopy of the X-ray flares observed in this state and found that the spectra can be fitted well using highly ionized absorption models. We further show that the spectra can also be fitted using a highly relativistic reflection dominated model, where for the lamp post geometry, the X-ray emitting source is al w ays very close to the central black hole. For both interpretations, the flare can be attributed to a change in the intrinsic flux, rather than dramatic variation in the absorption or geometry. These reflection dominated spectra are very similar to the reflection dominated spectra reported for active galactic nuclei in their low flux states. 2024 The Author(s). -
Time series forecasting for understanding potential buyer behavior with ecommerce
Ecommerce is a platform for e-business Companies and hawkers for dynamically responding consumer demand and supply. Furthermore, responses to the consumer include blot-from-blue service with great quality of appurtenances. Moreover, the Indian retail industry is currently ranking in the world's top five concerning the growth. Thus, data is a new oil for this era of digitization. Henceforth, Cluster and distance classifier plays an important role in data-related findings. Besides, the cluster will give an identical pattern of data with the inclusion of centroid for finding out useful information. Furthermore, an already formed identical cluster pattern will be useful for mapping with another cluster. Thus, in this way cluster mapping done. Mapped cluster pattern will be useful in establishing the customer relationship with products. Moreover, it leads to the profitability of the e-commerce platform. Thereafter, cluster mapping is align with the new RFM model for getting more clarity about the consumer-buying pattern. Besides, it helps in identifying the potential buyer consumer. Moreover, time series results obtained are positive for potential buyer behavior. Thus, when time series forecasting is used on the RFM model it gives rise potential buyer loyalty with an e-commerce platform. 2020 Ecological Society of India. All rights reserved. -
Time-dependent flow due to noncoaxial rotation of an infinite vertical surface subjected to an exponential space-dependent heat source: An exact analysis
The effect of an exponential space-dependent heat source on heat and mass transfer flow of a viscous fluid past an infinite vertical plate is examined. The flow is generated due to noncoaxial rotation of the infinite plate. The noncoaxial rotation creates sine or cosine oscillation in its plane and the fluid at infinity. The flow is assumed to be laminar and time-dependent. The mathematical formulation is developed by considering certain physical initial and boundary conditions. The Laplace transform method is utilized to obtain the exact solutions of the concentration, temperature as well as velocity fields. The Sherwood number, Nusselt number, and skin-friction coefficient are also calculated and presented in tabular form for various embedded parameters. The velocity distributions are obtained for three different cases. The obtained analytical expressions are found to be identical with published results in the limiting sense. 2019 Wiley Periodicals, Inc. -
Time-dependent flow due to noncoaxial rotation of an infinite vertical surface subjected to an exponential space-dependent heat source: An exact analysis /
Heat Transfer Asian Research, Vol.48, Issue 7, pp.3162-3185 -
Time-Dependent Nonlinear Convective Flow and Radiative Heat Transfer of Cu-Al2O3-H2O Hybrid Nanoliquid with Polar Particles Suspension: a Statistical and Exact Analysis
The statistical and exact analysis of heat transfer rate and skin friction coefficient of a nonlinear convective flow of Cu ? Al2O3 ? H2O hybrid nanofluid with polar particle suspension is performed. The heat transport phenomenon includes radiative heat effect. A micropolar fluid model is accounted. Exact solutions to the governing problem are found via Laplace transform method (LTM). The heat transfer rate and skin friction are analysed critically via statistical methods like probable error and regression models. The slope of linear regression of data points for skin friction and Nusselt number is estimated to quantify the increase/decrease. The Nusselt number and thermophysical properties for twenty-four different hybrid nanofluids are presented. A novel idea of a nonlinear convective flow of Cu ? Al2O3 ? H2O hybrid nanofluid with polar particle suspension is investigated for the first time. Opposite behaviour of velocity and microrotation profile are established when the physical parameters are varied. 2019, Springer Science+Business Media, LLC, part of Springer Nature.