Scientia Iranica
Volume:28 Issue: 6, Nov-Dec 2021

We considered a stagnation point of Non-Newtonian Fluid with Phase Flow Model over a stretching surface with slip conditions. Two types of the nanoparticle used, namely Cu and 〖Al〗_2 O_3 with base fluid H_2 O. Acceptable to theoretical study, the mathematical model has been constructed through flow assumptions. Partial differential equations are made by applying the boundary layer approximations on the momentum and energy equations. The suitable similarity transformations are applied to the partial equations which are converted into ordinary differential equations. These equations are solved by numerical scheme, namely BVP4C method. The involving physical parameters effect is shown by graphs and tables. Our work shows a good agreement with the decay literature. The expressions F''(0) and -θ'(0) achieve fewer values by hybrid nanofluid than that of nanofluid. Moreover F''(0) and -θ'(0) increase for large values of the dimensionless parameter (N) where as F'(ξ) and θ(ξ).increase for large values of Φ_2.

In this paper, we investigated the stagnation point flow of Maxwell viscoelasticity with incompressible based micropolar fluid over a Riga plate. The mathematical model has been constructed though micropolar fluid flows over Riga plate. The implement the boundary layer approximation, the system of partial differential equations is produced through momentum equation along with micro inertia theory. Nonlinear partial differential equations are become dimensionless nonlinear ordinary differential equations through suitable similarity transformations. This system is solved numerical scheme via BVP4C method. The effects of involving physical parameters like as dimensionless parameter, Modified Hartman number, Material parameter, Slip condition σ_s, Viscoelastic parameter δ_m and Soret coefficient S_T are highlighted through graphs and numerical results. The physical quantities like as Skin friction, local Nusselt number and local Sher-wood number are highlighted through tables. R is increasing with increasing dimensionless parameter, Material parameter K and Slip condition σ_s. R is decreasing with increasing behavior of Modified Hartman number Z and viscoelastic parameter δ_m.

Recently, the preparation of silver nanoparticles (AgNPs) by green technique has improved due to their fundamental applications in medicine. In this study, methadone syrup (ME) was used for the preparation of AgNPs as a reducing and stabilizing agent with the aim of in vitro cytotoxicity effect against the human breast cancer cells. The characteristics of prepared particles are investigated by transmission electron microscopy (TEM), environmental scanning electron microscopy (ESEM), energy-dispersive X-ray spectroscopy (EDS), dynamic light scattering (DLS), UV–visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction studies (XRD). The AgNPs (about 18 nm) were synthesized in a spherical shape and uniform distribution. The mechanism of ME through the synthesis has been proposed based on FT-IR analysis and density functional theory. To investigate the cytotoxicity of prepared AgNPs by ME, MTT assay was used in the range of 0-100 μg/mL. As a function of its dosage, the green synthetic AgNPs showed anti-proliferation activity against MDA-MB-468 cells respect to ME. The results demonstrated the feasibility of producing AgNPs in a simple, rapid, and green manner using ME, which has an important function in inhibiting the growth of breast cancer cells.

Due to the wide applications of self-cleaning surfaces in various industries such as textile, automotive, construction, agriculture, optics, marine and aerospace industries, the development of self-cleaning coating production methods in a simple and inexpensive way has been considered by researchers. In this paper, Tin oxide (SnO2) and Manganese (II, III) oxide (Mn3O4) were prepared via sol–gel procedure. Next, (Mn3O4/ SnO2) double-layers were deposited using spray pyrolysis system on glass substrates. According to AFM images of Mn3O4 thin films, grains are tightly packed, entirely compressed and without crack. AFM images of SnO2 films indicated that the width of grain was about 242.8 nm and RMS roughness was about 25.85 mm. These images for bilayer demonstrated that the grain width was about 130-220 nm and root-mean-square thickness was about 20 mm. The SnO2 and Mn3O4 films, and SnO2/Mn3O4 bilayer showed a direct optical band gap and hydrophilicity with water contact angle of 75◦, 31◦, and 70◦ respectively. Due to the importance and various applications of hydrophilic surfaces, in this research, thin layers of metal oxide were produced in a very simple way, among which the thin layer of Mn3O4 has good hydrophilicity.

In this article, an elaborated evaluation has been presented for the stratified MHD Jeffrey nanofluid flow towards a stretching surface in the presence of gyrotactic micro-organisms. The analysis of the flow by taking into consideration the viscous dissipation, Brownian motion, Joule heating and thermophoresis aspects. The governing nonlinear system of partial differential equations (PDEs), administering the flow, are turned to a group of the nonlinear ordinary differential equations (ODEs) via using an appropriate similarity transformation and later solved numerically by implementing the Keller-box approach with the help of algebraic software Matlab. The impacts of a variety of parameters on the fluid motion, heat, mass, density of the motile micro-organisms, skin friction, Nusselt number, Sherwood number and local density number of the motile micro-organisms are examined with the aid of graphs as well as tables. The results suggest that the motile micro-organisms density is a decreasing function of the Lewis number, Pecket number and microorganisms concentration difference. The Sherwood number and density rate of motile micro-organisms are bigger in the case of magnetic parameter and Lewis number. It is identified that temperature, density of nanoparticles and motile micro-organisms density stratification parameters lead to decrease the temperature and density of nanoparticles profiles.

The involvement of nanotechnology has brought advancements in the environmentaland medical applications. Recently, zinc oxide nanoparticle (ZnO NP) is commonly used totreat a wide range of bacterial and fungal skin infections due to its antimicrobial property.This investigation was intended to study the antimicrobial effect of ZnO NP on Pseudomonasaeruginosa by testing the bacterial inhibition and the morphological damages caused by ZnONP on P. aeruginosa. The results of the study at 24 h exhibited a typical dose dependant andsignificant (p> 0.05) inhibition on the growth of P. aeruginosa treated with 5 to 150 μg/mLof ZnO NP. The polysaccharides and polypeptides from P. aeruginosa cell wall were found tobe associated to the attachment of ZnO NPs on bacterial cells as illustrated in the Fouriertransform infrared (FTIR) spectrum. Furthermore, the scanning electron microscopy (SEM)images displayed the surface attachment of ZnO NPs on bacteria and the morphologicalchanges such as disrupted cell wall integrity, cell bending and cell distortion as the result ofZnO NPs interaction on the cell wall of P. aeruginosa.

A novel heterojunction plasmonic photocatalyst [Co(Saloph)(His)]/Ag-TiO2 as a nanohybrid material was applied for the photocatalytic activity towards the C-H bond cleavage of alcohols to the aldehyde using different oxidants, O2, H2O2, or TBHP under irradiation of visible-light and NHPI as co-catalyst. It was synthesized by photo-deposition of metallic silver nanoparticles on titanium oxide surface and follow it, modification with cobalt(II) Saloph complex under ultrasonic agitation condition using histidine linker to reach a photocatalyst under 50 nm in size and band gap 2.64 eV. The [Co(Saloph)(His)]/Ag-TiO2 nanohybrid was characterized with EDS, XRD, DRS, FT-IR, PL spectroscopies, FESEM imaging, and BET technique. The size This three-component plasmonic photocatalyst revealed high photocatalytic efficiency with 95% conversion and 99% selectivity in aerobic conditions. The higher photocatalytic performance of [Co(Saloph)(His)]/Ag-TiO2 than the Co(Saloph)/TiO2 and Ag-TiO2 NPs should be related to the localized surface plasmonic resonance (LSPR) of these motives. So, this three-component nanohybrid provides an efficient interfacial electron transfer process through a synergistic effect that allows producing a nanocatalyst, with advantages of stability and fast selective C-H bond activation alcohols at ambient temperature using O2 as an inexpensive environmental friendly oxidant.

In this research, the anticorrosion properties of epoxy-based nanocomposite coating were studied using the Taguchi statistical method. A L16 orthogonal array with the four factors of control at four levels each and two interactions was employed for preparation of nanocomposite coating by adding chitosan nanoparticles and alumina nanoparticles in various concentrations, temperatures and mixing times. The analysis of variance and signal-to-noise ratio showed the film coating for steel panels significantly increases the anticorrosion properties. The optimal conditions for preparation of nanocomposite coating were obtained alumina nanoparticles 2%, chitosan nanoparticles 2%, temperature of 20 °C and a mixing time of 30 minutes. Finally, the surface of the coating film was analyzed by SEM.