A novel metaheuristic called Chaotic Marine Predators Algorithm (CMPA) is proposed and investigated for the optimization of engineering problems. CMPA integrates the exploration merits of the ...recently proposed Marine Predators Algorithm (MPA) with the chaotic maps exploitation capabilities. Several chaotic maps were applied in the proposed CMPA to govern MPA parameters that eventually led to controlled exploration and exploitation of search. This study makes an initial attempt to explore and employ CMPA in decoding complex and challenging design and manufacturing problems. For performance evaluation of the proposed algorithm, CEC 2020 numerical problems having different dimensions and five widely adopted constrained design problems were solved. For all problems, both qualitative and qualitative results are examined and discussed. Moreover, two case studies of multi-pass turning were examined by the proposed CMPA algorithm to optimize the cutting operation with a minimum cost of production per unit objective. Furthermore, the suggested CMPA algorithm has been investigated for solving a real-world structural topology optimization problem. Statistical analysis is performed, and the results of CMPA are compared with twelve distinguished algorithms. Outcomes of the proposed variant algorithm on the benchmarks demonstrate its significantly improved performance relative to other optimizers including a variant of MPA and two state-of-the-art IEEE CEC competitions winners algorithms. Findings from the manufacturing process exhibit CMPA proficiency in solving arduous real-world design problems.
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•A novel Chaotic Marine Predators Algorithm is developed.•Theoretical and numerical comparisons are extensively investigated.•The results show the merits of the proposed hybrid method used in solving the real-world case studies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Here we report a novel regulatory mechanism for autophagy-mediated degradation of Mycobacterium tuberculosis (Mtb) and specific strategy exploited by the virulent Mtb to evade it. We show while both ...avirulent (H37Ra) and virulent (H37Rv) mycobacteria could readily localize to autophagosomes, their maturation into autolysosomes (flux) was significantly inhibited by the latter strain. The inhibition of autophagy flux by the virulent strain was highly selective, as it did not perturb the basal autophagy flux in the macrophages. Selective inhibition of flux of Mtb-containing autophagosomes required virulence regulators PhoP and ESAT-6. We show that the maturation of Mtb-containing autophagosomes into autolysosomes required recruitment of the late endosome marker RAB7, forming the intermediate compartment amphisomes. Virulent Mtb selectively evaded their targeting to the amphisomes. Thus we report a crosstalk between autophagy and phagosome maturation pathway and highlight the adaptability of Mtb, manifested by selective regulation of autophagy flux.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In this work, we investigate the hydrothermal characteristics for laminar forced convective flow of water through sinusoidal asymmetric wavy channel of three types: linearly increasing amplitude ...channel (LIAC), linearly decreasing amplitude channel (LDAC) and constant amplitude channel (CAC). The computed velocity and temperature fields are analyzed by varying the Reynolds number (Re) and slope (A) of the linearly varying amplitude in the following ranges: 5 ≤Re≤ 200 and 0.02≤A≤ 0.04. The value of average Nusselt number is almost independent on the geometry of the channel at lower values of Re and A. At higher Re values, the average Nusselt number is the highest for LIAC followed by LDAC, and CAC. The combined effects of heat transfer increase in the wavy channel compared to plane channel and the associated pumping power is assessed using performance parameter (PF). For lower Re values the highest PF is obtained for CAC. For higher values of Re the PF is the largest for LDAC at A = 0.02 and 0.03, and the value of PF for A = 0.04 is the highest for CAC.
•Effects of Re and wall amplitude A studied for forced convective flow in a wavy channel.•Linearly increasing (LIAC), decreasing (LDAC), constant amplitude (CAC) channels used.•For higher Re, average Nu is highest for LIAC, followed by LDAC, then CAC.•Performance parameter (PF) used to assess heat transfer and pumping power.•For lower Re CAC has highest PF; for higher Re, PF is strongly dependent on A.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We investigate the flow and mixing characteristics for an electroosmotic flow through a wavy micromixer using surface charge heterogeneity. The Laplace equation for the external electric field, ...Poisson–Boltzmann equation for potential distribution, and continuity and momentum equations for fluid flow and species transport equation have been solved by imposing the appropriate boundary conditions using a finite element method-based numerical solver. The results are presented by varying the phase lag of sinusoidal zeta potential between the two walls (Δϕ), Debye parameter (κ), geometrical wave number (n), dimensionless wall amplitude (α), and diffusive Peclet number (Pe). The results reveal that the phase lag has a strong confluence on the flow field and mixing performance together with other physicochemical parameters. The strength of primary flow as well as the size of the recirculation zones increases with Δϕ and κ, and additional recirculation zones are formed in the core of the mixer for Δϕ = 0. The value of mixing efficiency is close to 100% up to a critical value of Pe (Pe Cri), the value of which is greater for the nonuniformly charged surface potential with a nonzero phase lag. For thinner EDL (κ = 150), a fully mixed state based on 90% mixing is achieved up to higher values of Pe with a higher flow rate at Δϕ = π/2 and π. Also, for Δϕ = π/2, the mixing efficiency as well as the flow rate enhances with the amplitude of the channel walls for Pe Cri ≤ Pe ≤323.5. Moreover, for Δϕ = 0, the value of mixing efficiency increases with α for 786 ≤ Pe ≤1000 with a 9.17% decrement in the flow rate for the change in α from 0.05 to 0.25.
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IJS, KILJ, NUK, PNG, UL, UM
We analyse the thermo-hydraulic performance and entropy-generation characteristics for laminar flow through triangular corrugated channel. Results are presented in terms of heat transfer, pressure ...drop and entropy generation for different values of amplitude of waviness of the channel, wavelength and Reynolds number in the range of 5–500. It is found that the rate of heat transfer is augmented with both Reynolds number and amplitude of the wall waviness, together with increase in pressure drop. The enhancement in heat transfer and pressure drop as compared to equivalent straight channel are also assessed by performance factor combining the enhancement in heat transfer and corresponding increase in pressure drop. There is an intricate interplay between the geometrical parameters of the channel and the flow parameters in dictating the performance factor. Thermal entropy generation is dominant over the fluid friction for lower Reynolds number. The total entropy generation increases rapidly up to critical Reynolds number (
Re
cri
), after which it either remains almost constant or decreases gradually, and moreover
Re
cri
depends on the wavelength of the channel. The outcomes of the present work may be helpful to design the efficient and economic thermal devices and systems.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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
We propose a micromixer for obtaining better efficiency of vortex induced electroosmotic mixing of non‐Newtonian bio‐fluids at a relatively higher flow rate, which finds relevance in many biomedical ...and biological applications. To represent the rheology of non‐Newtonian fluid, we consider the Carreau model in this study, while the applied electric field drives the constituent components in the micromixer. We show that the spatial variation of the applied field, triggered by the topological change of the bounding surfaces, upon interacting with the non‐uniform surface potential gives rise to efficient mixing as realized by the formation of vortices in the proposed micromixer. Also, we show that the phase‐lag between surface potential leads to the formation of asymmetric vortices. This behavior offers better mixing performance following the appearance of undulation on the flow pattern. Finally, we establish that the assumption of a point charge in the paradigm of electroosmotic mixing, which is not realistic as well, under‐predicts the mixing efficiency at higher amplitude of the non‐uniform zeta potential. The inferences of the present analysis may guide as a design tool for micromixer where rheological properties of the fluid and flow actuation parameters can be simultaneously tuned to obtain phenomenal enhancement in mixing efficiency.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
For liquids used in biological applications, a smaller diffusion coefficient results in a longer mixing time. We discuss, in this endeavor, the promising potential of the AC electrothermal (ACET) ...effect toward modulating enhanced mixing of electrolytic liquids with higher convective strength in a novel wavy micromixer. To this end, we develop a modeling framework and numerically solve the pertinent transport equations in a three-dimensional (3D) configuration numerically. By benchmarking the developed modeling framework with the experimental results available in this paradigm, we aptly demonstrate the maximum temperature rise, flow topology, species concentration field, and mixing efficiency in the proposed configuration for a set of parameters pertinent to this analysis. We find that the maximum temperature increase in the wavy micromixer, owing to the electrothermal effect, is less than 10 K even for the higher strength of the applied voltage, implying nondegradation of biological substances within the liquid sample. We report that the formation of significant lateral flow closer to the electrodes leads to a highly three-dimensional ACET flow field, which has a significant impact on the mixing efficiency for the range of diffusive Peclet numbers considered. We also report that the wave amplitude of the mixer, when intervening with the diffusive Peclet number, strongly impacts the mixing efficiency. As witnessed in this endeavor, for the smaller diffusive Peclet number, the mixing efficiency increases with amplitude, while the effect becomes the opposite for the higher Peclet number. The results of this study seem to provide an adequate basis for the design of a novel micromixer intended for enhanced solute mixing in realistic microfluidic applications.
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IJS, KILJ, NUK, PNG, UL, UM
We have investigated the role of viscoelectric effect on diffusioosmotic flow (DOF) through a nanochannel connected with two reservoirs. The transport equations governing the flow dynamics are solved ...numerically using the finite element technique. We have extensively analyzed the variation of induced field due to electric double layer (EDL) phenomenon, relative viscosity as modulated by the viscoelectric effect as well as reservoir's concentration difference, and their eventual impact on the underlying flow characteristics. It is revealed that the induced electric field in the EDL enhances fluid viscosity substantially near the charged wall at a higher concentration. We have shown that neglecting viscoelectric effect in the paradigm of diffusioosmotic transport overestimates the net throughput, particularly at a higher concentration difference. Furthermore, we show that pertaining to chemiosmosis dominated regime, the average flow velocity modifies with the increase in concentration difference up to a critical value. In comparison, the rise in the strength of resistive electroosmotic actuation by the accumulation of anions in the upstream reservoir reduces the average flow velocity at a higher concentration difference. We have reported a reduction in critical concentration with the increase in viscoelectric effect. The inferences of this analysis are deemed pertinent to reveal the bearing of viscoelectric effect as a flow control mechanism pertaining to DOF at nanoscale.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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•The mixing and pressure drop characteristics are analyzed for flow through wavy micromixer.•Comparison between raccoon and serpentine micromixers are reported.•Three different flow ...regimes are identified depending on the parameters influencing the mixing quality.•The mixing is better for raccoon mixer as compared to serpentine one.•The pressure drop is always higher for raccoon mixer as compared to serpentine mixer.
We numerically analyze the mixing and pressure drop characteristics for flow through wavy micromixer of two geometrical configurations, namely raccoon and serpentine for different values of amplitude of the waviness of the mixer (α), wavelength of the waviness (λ), Reynolds number(Re) and Schmidt number(Sc). Three different flow regimes are identified depending on the parameters influencing the mixing index. The mixing index for both the raccoon and serpentine mixer is very close to unity in the first regime (0.1 < Re < Re*). Beyond Re*, the mixing is better for raccoon mixer as compared to serpentine for any particular value of Re, amplitude and wavelength. In case of the absence or insignificant size of recirculation zone, beyond Re* the difference in mixing index between raccoon and serpentine mixer increases with Re, while the same decreases in presence of significant size of recirculation zone within the mixer. The pressure drop is always higher for raccoon mixer as compared to serpentine and moreover, the difference in pressure drop between raccoon and serpentine mixer increases with increase in Re. The best micromixer has been proposed based on the findings of the present analysis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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