Abstract
In this article, we demonstrate the solution methodology of start-up electrokinetic flow of non-Newtonian fluids in a microfluidic channel having square cross-section using Spreadsheet ...analysis tool. In order to incorporate the rheology of the non-Newtonian fluids, we take into consideration the Ostwald-de Waele power law model. By making a comprehensive discussion on the implementation details of the discretized form of the transport equations in Spreadsheet analysis tool, and establishing the analytical solution for a special case of the start-up flow, we compare the results both during initial transience as well as in case of steady-state scenario. Also, to substantiate the efficacy of the proposed spreadsheet analysis in addressing the detailed flow physics of rheological fluids, we verify the results for several cases with the corresponding numerical results. It is found that the solution obtained from the Spreadsheet analysis is in good agreement with the numerical results—a finding supporting spreadsheet analysis's suitability for capturing the fine details of microscale flows. We strongly believe that our analysis study will open up a new research scope in simulating microscale transport process of non-Newtonian fluids in the framework of cost-effective and non-time consuming manner.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The present study numerically explores the thermally radiative incompressible flow of hybrid nanofluid due to the stretchable rotational disk with the consideration of externally applied magnetic ...field and examines the underlying transport of heat both qualitatively as well as quantitatively. Pertaining to this study, the traditional von Karman approach is applied to convert partial derivative form of governing nonlinear transport equations into ordinary derivative form and is then evaluated by using an efficient boundary value problem (BVP4c) solver. The simulated results of flow-field variables such as velocity, temperature, friction-factor coefficients for various physical factors have been discussed both apparently in graphical form as well as numerically in the tabular form. In addition, we aptly discussed the influence of entropy heat generation and Bejan number obtained for different physical parametric values on the underlying thermohydrodynamics. The results indicate that the radial and tangential velocities across the rotating disk decrease for greater values the magnetic parameter (M) and slip factor (γ). As shown in this study, the effect of augmented fractional volume (ϕ2) leads to a decrease of the fluid velocity owing to the accumulation of the nanoparticles in the working fluid. An increasing the value of magnetic and radiation parameters results in thickening the thermal boundary layer, which in turn induce an enhancement in the fluid temperature. Finally, it is seen that for an intense effect of the thermal radiation and viscous dissipation, the thermodynamic irreversibility in the present system becomes higher. We believe that the developed modelling frame-work has the potential to effectively analyze the underlying fluid flow and heat transfer in turbomachinery, high-end heat transfer process applications.
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•Effect of Magnetic field and radiation on the Hybrid-nanofluid flow in a rotating disk.•Increase in radiation and magnetic parameters invite higher thermodynamic Irreversibility.•The von Karman approach is employed in the solution method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Flow dynamics of viscoelastic fluid being squeezed and extruded between two plates.•Oldroyd-B fluid model is used to describe the rheology of viscoelastic fluid.•Elastic stresses and its ...interactions with squeezing force affect the flow dynamics.
We investigate the flow dynamics of a viscoelastic fluid squeezed and extruded between two parallel plates. We use the Oldroyd-B fluid model to describe the fluid rheology, in an effort to capture the essential flow features. We unveil the force distribution in the flow-field, as a function of the extrusion and squeezing parameters. We attribute alterations in these forces as a combined consequence of the stress modifications under the simultaneous action of squeezing and extrusion and its interplay with the elastic stress originating from the viscoelastic effects. We believe that the inferences obtained from the present study may bear significant consequences in the design of various processes such as compression moulding, for potential use in microscale and nanoscale patterning.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Rising climate disasters underscore the overlooked impact of heat stress on health and productivity in densely populated Southeast Asia, particularly vulnerable coastal areas like India's. This study ...in the Indian Sundarbans employs surveys and social network analysis to explore heat stress effects, community adaptation, and support networks. Recognizing community significance, it views resilience as a blend of agency, wisdom, and networks. The research unveils rural adaptive behaviours, co-occurring stress responses, and network use for health solutions. These insights aim to enhance health advisories and crisis responses, fostering resilience in communities facing escalating climate challenges. The research covered 747 households from nine village segments, examining heat stress adaptation and social support networks. Social Network Analysis revealed internal and external sources of support for heat stress-induced health issues. The study employed matrices and network analysis tools to represent co-occurrence patterns of adaptation strategies and support networks. Findings highlighted collective adaptive behaviour and the role of social connections in combating climatic stress. The study outlines dual interventions to mitigate heat stress impacts: enhancing endogenous community adaptability and optimizing social-institutional networks for external support. Occupational profiling, socio-economic context, and health access can identify vulnerable groups. Perceived impacts can serve as early health crisis indicators, though not always linked to adaptive actions. Diverse adaptive activities co-occur, reflecting collective behaviour, but less central actions require attention. Medical care usage for heat stress remains minimal. Social networks lack local health providers needing community-level provisions. A comprehensive mitigation plan for identified vulnerable communities aims to bridge knowledge gaps, promote equitable healthcare access, and strengthen adaptive capacity through informed interventions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Transient rotational electro-osmotic microflows of a viscoelastic fluid•Oldroyd-B fluid model is used to describe the rheology of viscoelastic fluid•Rotation induced modifications in elastic ...stresses lead to affluent flow dynamics•Complex flow dynamics leads to enhance in mixing in the microfluidic channel
We analyze the transiences in rotational electro-osmotic flow of a viscoelastic fluid in a microfluidic channel. We here use Oldroyd-B equations to model the viscoelastic fluid. We bring out the rotation induced complex flow dynamics during the transience, leading to possible augmentations in mixing, as modulated by the modifications in the force distribution in the flow-field. We attribute alterations in these forces as a combined consequence of the modifications in stress under the simultaneous action of rotation and electrical forcing and its interplay with the elastic stress originating from the viscoelastic effects. We also highlight on the volumetric transport characteristics as dictated by the underlying dynamical conditions. The inferences obtained from the present study may bear significant consequences in the design of various microfluidic devices, which are commonly used for the transportation of bio-fluids such as blood.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
We investigate the effect of viscous dissipation on the thermal transport characteristics of heat and its consequence in terms of the entropy-generation rate in a circular Couette flow. We consider ...the flow of a Newtonian fluid through a narrow annular space between two asymmetrically-heated concentric micro-cylinders where the inner cylinder is rotating at a constant speed. Employing an analytical methodology, we demonstrate the temperature distribution and its consequential effects on the heat-transfer and entropy-generation behaviour in the annulus. We bring out the momentous effect of viscous dissipation on the underlying transport of heat as modulated by the degree of thermal asymmetries. Our results also show that the variation of the Nusselt number exhibits an unbounded swing for some values of the Brinkman number and degrees of asymmetrical wall heating. We explain the appearance of unbounded swing on the variation of the Nusselt number from the energy balance in the flow field as well as from the second law of thermodynamics. We believe that the insights obtained from the present analysis may improve the design of micro-rotating devices/systems.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
We investigate the Marangoni instability in a thin polymeric liquid film heated from the free surface. The polymeric solutions are usually a binary mixture of a Newtonian solvent with a polymeric ...solute, and exhibit viscoelastic behaviour. In the presence of a temperature gradient, stratification of these solutes can take place via the Soret effect, giving rise to the solutocapillary effect at the free surface. Considering this cross-diffusive effect and incorporating the effects of gravity, here we analyse the stability characteristics of this polymeric film when bounded between its deformable free surface and a poorly conductive rigid substrate. Linear stability analysis around the quiescent base state reveals that, under the combined influences of thermosolutocapillarity and the elasticity of the liquid, apart from the monotonic disturbances, two different oscillatory instabilities can emerge in this system. The characteristics of each instability mode are discussed, and a complete stability picture is perceived in terms of the phase diagrams, identifying the model parameter regimes for which a particular instability mode becomes dominant.
Pertaining to the mixing of the non-Newtonian Carreau fluid under electrokinetic actuation inside a plane microchannel, we propose a new design of micromixer that involves inserting a two-part ...cylinder bearing zeta potential of the same sign but different magnitude in the upstream and downstream directions. We numerically solve the transport equations to predict the underlying mixing characteristics. We demonstrate that a substantial momentum difference between the microchannel's plane wall and cylinder leads to the development of a vortex in the flow pathway, which in turn, enhances mixing substantially. As shown, for a fluid having a highly shear-thinning nature, the vortex-assisted convection mixing strength increases with diffusivity of the candidate fluids. Moreover, it is shown that for the higher shear-thinning nature of the candidate fluid, an increase in cylinder radius enhances mixing efficiency and flow rate simultaneously, resulting in a "quick and efficient" mixing condition. Additionally, the fluid rheology significantly alters the kinetics of shear-induced binary aggregation. Our findings show that the shear-induced aggregation characteristic time sharply increases with increasing shear-thinning behavior of the fluid.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Emphysema is a lung disease that occurs due to abnormal alveoli expansion. This chronic disease causes difficulty in breathing which can lead to lung cancer. The progressive destruction of emphysema ...can be assessed by Computed Tomography (CT) scans and pulmonary function tests. The severity of the disease may extend to a stage where one can risk their life emphasizing the early detection of emphysema. Primary diagnosis can be done using spirometry and CT for early detection of the disease reducing the mortality rates. Difficulties associated with different diagnostic procedures and inter and intraobserver variations have made blooming researches on more computer-aided techniques. This paper intends to develop a computer-aided technique using the improved deep learning strategy. The initial process is image pre-processing, which is performed by histogram equalization and median filtering. Further, the Fuzzy C Means (FCM) clustering is used for segmentation. After segmentation, a new Adaptive Local Ternary Pattern (ALTP) is used for extracting the pattern descriptor, which is further utilized for classification. As a new contribution, the Parameter Optimized-Faster Region Convolutional Neural Network (PO-FRCNN) is developed for performing the diagnosis. The enhancement of pattern formation and deep classification is accomplished by the Improved Red Deer Algorithm (IRDA), which helps to tune the significant parameters that have a positive influence on the accurateness. The benchmark and real-time dataset are used for performing the experimentation. The results show that the proposed method yields the best result and can effectively diagnose emphysema when compared to state-of-the-art techniques.
In this article, we discuss the bioinspired peristaltic pumping mechanism of an elastic non-Newtonian fluid whose rheology is characterized by the Phan-Thien-Tanner model in a microfluidic ...configuration. We consider the effect of an electroosmotic body force originating from electrical double layer phenomena formed in the wall of the fluidic channel of finite length. The considered configuration is consistent with the natural contraction of the oesophagus wall that does not involve expansion beyond the stationary boundary. Employing lubrication theory and assuming the underlying flow to be in the creeping flow regime, we outline the transport equations pertaining to the chosen peristaltic set up. The transport equations are then solved using a well-established method consistent with perturbation technique. By depicting the pressure variation and wall shear stress graphically for a continuous wave train, we aptly discuss the time-averaged net throughput and flow developed at channel inlet of the chosen pathway and demonstrate the eventual consequences of these flow patterns for a window of viscoelastic and electrokinetic parameters. The outcomes obtained from this model establishes that the underlying flow owing to the peristaltic pumping mechanism strongly relies on the rheological parameter
ε
W
e
2
. These inferences are expected to be of extensive importance in designing peristalsis pump, mimicking features of the physiological system, for achieving unidirectional flow of complex fluids with improved efficiency, frequently used in biochemical/biomicrofluidic applications.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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