Squeezed MHD tangent hyperbolic fluid flow across a sensor surface

In the present numerical study, the combined effect of temperature-dependent thermal conductivity, linear thermal radiation, and magnetic effect on shear-thinning tangent hyperbolic fluid past a sensor surface has been studied. After converting the modelled partial differential equations into ordinary differential equations by using similarity transformation, the system of equations is tackled with the aid of the shooting method. The influence of important parameters on the fluid motion and energy distribution is displayed graphically and analyzed in detail. The presented simulations depict that a significant rise in fluid velocity is noticed for an enhancement in the magnetic parameter while an opposite trend is observed for the temperature distribution. Moreover, the skin friction coefficient decreases as the squeezed flow index is increased.     

Preparation and characterization of strong cation exchange terpolymer resin as effective adsorbent for removal of disperse dyes

In this study, (hydroxypropylmethacrylate-co-ethyleneglycol dimethacrylate-co-glycidylmetharylate) terpolymer resin functionalized with sulfonic acid groups was prepared and used as cation exchange resin for removal of two different disperse dyes (i.e., Direct Red R [DR-R] and Disperse Violet 28 [DV-28]) from aqueous solution. The properties of the adsorbent were determined using Fourier transform infrared, dynamic light scattering, scanning electron microscopy, and Brunauer, Emmett, and Teller methods. The maximum adsorption capacity of the resin for the DR-R and DV-28 was found to be 86.1 and 179.6 mg/g, respectively. Desorption study was realized to evaluate the reusability of the resin and the percent desorption from the resin for DR-R and DV-28 dyes was found to be approximately 89.4% and 91.7%, respectively. The experimental data were evaluated using different kinetics and isotherm models. These results show that the experimental data could be designated with the second-order kinetic model and both Langmuir and Temkin isotherm models. Finally, the presented resin was able to remove large amounts of organic pollutants in a short process time with a low amount of adsorbent. Thus, it was shown that the prepared resin has high potential for use as an effective and sustainable adsorbent for the treatment of industrial wastewater. POLYM. ENG. SCI., 60:192–201, 2020. © 2019 Society of Plastics Engineers     

Pollen morphological investigations of family Cactaceae and its taxonomic implication by light microscopy and scanning electron microscopy

The family Cactaceae is the diversified group of angiosperm plants whose pollen statistics has been used for taxonomic identification. In this article, we present the pollen morphology of eight species belong to seven taxonomically complex genera of Cactaceae including Astrophytum, Cylindropuntia, Echinocereus, Echinopsis, Mammillaria, Opuntia, and Thelocactus using light and scanning electron microscopy. The pollen grains were acetolyzed, measured, described, and electron photomicrographs were taken. Cactaceae can be characterized by presenting different palynomorphological features including pollen type, sculpturing, polar and equatorial diameter, aperture orientation, exine thickness, P/E ratio, and echini features. Four types of pollen shapes, that is, prolate spheroidal (three species), subprolate (two species), prolate (two species), and oblate spheroidal in Echinocereus reichenbachii were observed. The polar and equatorial diameter observed maximum in O. ficus indica 116.95 and 112.27 μm while minimum in M. compressa 38.42 and 21.05 μm. Pollen of two types, tricolpate in members of subfamily Cactioideae and pantoporate in the Opuntioideae were examined. The fertility percentage has been observed maximum in Opuntia macrocentra (83.84%) and minimum in Opuntia ficus‐indica (57.89%). Exine sculpturing showing great variations such as granulate, reticulate, granulate perforate and micro‐echinate foveolate ornamentation was examined only in Echinopsis eyriesii. A key to species, based on pollen micromorphological attributes, has been constructed for correct identification of complex cactus species.     

Facile Synthesis of Ferrocene-Based Polyamides and Their Organic Analogues Terpolyamides: Influence of Aliphatic and Aromatic Sequences on Physico-Chemical Characteristics

Efforts have been devoted to synthesize and characterize processable polymers with desired properties. Herein, four different series of aromatic and aliphatic terpolyamides were prepared via solution phase polycondensation of 4,4′-oxydianiline and hexamethylenediamine (HMDA) with various diacids chlorides (isophthalyol dichloride, terepthalyol dichloride, 1, 1′-ferrocene dicarboxylic acid chloride and trans-azobenzene-4, 4′-dicarbonyl chloride). The structural, morphological and physico-chemical nature of as prepared polymers was explored by Fourier-transform infrared spectroscopy, scanning electron microscopy, thermal analysis (TGA and DSC), and wide-angle x-ray diffraction. Moreover, an aliphatic diamine was incorporated in varying concentration as a flexible methylene spacer and the effect of its concentration on the properties of polyamides was also studied. Changes in various physico-chemical properties such as solubility, inherent viscosity, surface morphology and flame retarding behaviour were investigated. Marked difference in morphology and solubility was observed with the change in the ratio of segments in the chain. Inherent viscosities of polymers ranged from 1.8052–1.6274 dl/g indicating reasonably moderate molecular weights. Interestingly, ferrocene based aromatic polymers were more thermally stable (T_g 260 °C, T_i 310 °C, T_h 525 °C, T_f 720 °C, for PF₀), and also found to exhibit best flame retarding behavior (limiting oxygen index value for PF₀is LOI 33.15%).

     

Influence of metal‐oxide‐supported bentonites on the pyrolysis behavior of polypropylene and high‐density polyethylene

In this article, we report on the pyrolysis of polypropylene (PP) and high‐density polyethylene (HDPE) in the absence and presence of plain and metal‐oxide‐impregnated bentonite clays [BCs; acid‐washed bentonite clay (AWBC), Zn/AWBC, Ni/AWBC, Co/AWBC, Fe/AWBC, and Mn/AWBC] into useful products. Thermal and catalytic runs were performed at 300°C in the case of PP and at 350°C in the case of HDPE for a contact time of 30 min. The effects of different catalysts and their concentrations on the overall yields and the yields of liquid, gas, and residue were studied. The efficacy of each catalyst is reported on the basis of the highest liquid yields (in weight percentage). The derived liquid products were analyzed by Fourier transform infrared spectroscopy and gas chromatography–mass spectroscopy; this confirmed the presence of paraffins, olefins, and naphthenes. The results indicate the catalytic role of impregnated BCs compared to plain BC with the optimum efficiency shown by Co/AWBC in the case of PP and Zn/AWBC in the case of HDPE toward the formation of liquid products in a desirable C range with the enrichment of olefins and naphthenes in the case of PP and paraffins and olefins in the case of HDPE compared to the thermal run. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41221.     

A Review on Polymeric Nanocomposites of Nanodiamond,Carbon Nanotube,and Nanobifiller: Structure,Preparation and Properties

In this review, an overview of various types of nanofillers is presented with special emphasis on structure, synthesis and properties of carbon nanotube, nanodiamond, and nanobifiller of carbon nanotube/nanodiamond, carbon nanotube/graphene oxide and carbon nanotube/graphene. In addition, polymer/carbon nanotube, polymer/nanodiamond, and polymer/nanobifiller composites have been discussed. The efficacy of different fabrication techniques for nanocomposites (solution casting, in-situ, and melt blending method) and their properties were also discussed in detail. Finally, we have summarized the challenges and future prospects of polymer nanocomposites reinforced with carbon nanofillers hoping to facilitate progress in the emerging area of nanobifiller technology.     

Transformation and intensification of tornado-like flow in a narrow channel during elongation of an oval dimple with constant area

Technical Physics Letters - Reynolds averaged Navier–Stokes equations closed using the Menter shear-stress-transfer model have been numerically solved on multiblock intersecting structured...     

Promoting Photocatalytic Cleaning Efficiency of Textile Finishing Solutions with Nanoboron as a p-Type Dopant

Boron is a commonly used p-type dopant for semiconductor and photonic applications. In this study, standard photocatalytic titanium dioxide (TiO₂) particles were doped with nanosized boron particles and coated on textiles to bring the photocatalytic light intensity closer to the visible light range. Boron/titania nanoparticle composites were initially prepared in DI water solutions and studied for their photocatalytic response through a statistical central composite design. To determine the most effective titania and nanoboron particle blend for photocatalytic textile coating, absorbance and stain bleach analyses were performed by UV light exposure. The performance of the composite particles at the optimal concentration has also been evaluated in the finishing solution and compared with the performances of the pure titania particles. It was found that the textiles coated with 0.08 wt% anatase doped with 0.16 wt% nanoboron as a p-type dopant provided improvement in self-cleaning ability under the visible light range in the DI water environment. Energy band gap calculations further verified the nanoboron-doped titania blend to have a lower energy barrier as compared with the 0.1 wt% anatase in agreement with the photocatalytic activity improvements. Nanoboron is shown to be a strong candidate as a p-type dopant to titania for photocatalytic textile coatings.