A two-stage stress-dependent creep mechanism in plasticized poly(vinyl chloride) (PVC)

The temperature dependence of tensile creep of plasticized poly(vinyl chloride) (PVC) was tested under differently applied stresses. The steady creep rate showed two distinct stages, depending on stress and temperature. At relatively low stresses the activation energy (0.2 eV) which characterized the steady creep mechanism of stage I, showed no stress sensitivity. Under high stresses (stage II) the energy-activating steady creep was of the order of 1 eV and increased excessively with increasing stress. The model for plastic flow of PVC suggested here assigns the extension of the twisted zigzag molecular conformation to creep in stage I. In stage II creep is controlled by the reorientation of molecular segments by rotation from initially random orientations in a direction parallel to the principal tensile axis. γ Irradiation of the samples before testing increased the steady creep rate and reduced the creep lifetime. This was attributed to chain scission and greater mobility of the molecular segments.     

Synthesis and characterization of a Ni nanoparticle stabilized on Ionic liquid‐functionalized magnetic Silica nanoparticles for tandem oxidative reaction of primary alcohols

In this research, preparation of the magnetic nanoparticle, coating by a silica shell using (3‐aminopropyl) triethoxysilane and synthesis of a novel sulfonic acid‐substituted imidazolium‐based ionic liquid onto the surface of these particles via a multi‐component reaction, is described. The functionalized nanoparticles was loaded by Ni nanoparticles and characterized by means of techniques such as XRD, FTIR, SEM, EDX, TEM, TGA and ICP‐OES. The nanostructures have spherical shapes that ranged in size from 80 to 100 nm. The catalytic activity of these nanoparticles was tested in aerobic oxidation of primary alcohols that showed good performance in the wide range of primary alcohols in water at mild reaction conditions. As a second step of this work, the tandem oxidative synthesis of alkylacrylonitriles and bisindolylmethanes were investigated using primary alcohols under oxidation conditions. This catalyst system can be recovered using external magnet and reused for five consecutive cycles without significantly less of its activity.     

Radiolabelling of TiO<Subscript>2</Subscript> nanoparticles for radiotracer studies

Industrially manufactured titanium dioxide nanoparticles have been successfully radiolabelled with ⁴⁸V by irradiation with a cyclotron-generated proton beam. Centrifugation tests showed that the ⁴⁸V radiolabels were stably bound within the nanoparticle structure in an aqueous medium, while X-ray diffraction indicated that no major structural modifications to the nanoparticles resulted from the proton irradiation. In vitro tests of the uptake of cold and radiolabelled nanoparticles using the human cell line Calu-3 showed no significant difference in the uptake between both batches of nanoparticles. The uptake was quantified by Inductively Coupled Plasma Mass Spectrometry and high resolution γ-ray spectrometry for cold and radiolabelled nanoparticles, respectively. These preliminary results indicate that alterations to the nanoparticles’ properties introduced by proton bombardment can be controlled to a sufficient extent that their further use as radiotracers for biological investigations can be envisaged and elaborated.     

Solid–liquid phase equilibria for binary mixtures of propellant’s stabilizers

Solid–liquid equilibria for three binary mixtures of N-(2-acetoxyethyl)-p-nitroaniline (1) + 2-nitrodiphenylamine (2), N-(2-acetoxyethyl)-p-nitroaniline (1) + ethyl centralite (2) and N-(2-acetoxyethyl)-p-nitroaniline (1) + methyl centralite (2) have been determined experimentally using differential scanning calorimeter (DSC). Simple eutectic behaviours for these systems have been observed. The experimental results have been correlated by means of NRTL and UNIQUAC equations. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.61 to 3.32 K and depend on the particular model used. The best solubility correlation has been obtained with the UNIQUAC model.     

Experimental determination and prediction of (solid + liquid) phase equilibria for binary mixtures of heavy alkanes and fatty acids methyl esters

Solid–liquid equilibria for three binary mixtures of {n-eicosane (1) + methyl palmitate (2)}, {n-tetracosane (1) + methyl stearate (2)} and {n-octacosane (1) + methyl stearate (2)} were measured using differential scanning calorimeter. Simple eutectic behaviours for these systems were observed. The experimental results were correlated by means of the modified UNIFAC (Larsen and Gmehling versions), UNIQUAC and ideal models. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.21 K (for UNIQUAC model) to 1.07 K (for Ideal model) and depend on the particular model used. The best solubility correlation was obtained with UNIQUAC model.     

Polyol-modified layered double hydroxides with attenuated basicity for a truly reversible capture of CO2

Dendrimers bearing hydroxyl groups supported by layered double hydroxides (CO₃–LDH) with Mg/Al ratio ranging from 1:1 to 5:1 showed improved properties for the reversible capture of carbon dioxide (CO₂). The adsorption capacity of the starting LDH was due to the intrinsic base-like behavior, and was found to depend on the Mg/Al ratio. When contacted with polyol dendrimers in aqueous media, no intercalation took place. This was explained in terms of low exfoliation grade of LDH and hydrophobic character of the dendrimer molecules. The latter rather adsorb on the external surface of the LDH stacks for low dendrimer loadings, or aggregate into organic clusters for higher contents. Analyses through thermal programmed desorption of CO₂ revealed that dendrimer incorporation advantageously attenuates the basicity strength of the starting LDH support, by lowering the desorption temperature. The OH groups of the organic moiety were found to display an amphoteric character, and act as the main adsorption sites. The weak interactions with CO₂ facilitate easier release of the major part of adsorbed CO₂ at temperature not exceeding 80–100 °C. On polyol organo-LDHs, the reversible CO₂ retention was discussed herein in terms of acid–base interactions. This concept allows envisaging the capture of diverse pollutants and other greenhouse gases by modifying the chemical groups on the dendritic moiety.     

Facile synthesis of silver doped-copper oxide nano materials utilizing areca catechu (AC) leaf extract and their antidiabetic and anticancer studies

The present research highlights physical significance of green combination of metal oxide nanomaterials utilizing medicinal plant which has widely analyzed in different medical applications i.e., medicinal science, therapeutics. In this paper, we discussed environmentally benign approach for synthesizing silver doped copper oxide nanoparticles (Ag–CuO NPs) utilizing (ACLE). Scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were utilized to confirm the size, crystalline structure and surface morphology of the obtained nanomaterials. The monoclinic crystalline structure of the Ag–CuO NPs as produced was revealed by XRD patterns. Morphological analysis disclosed the nano-based spherical configuration of Ag–CuO NPs, as well as their morphology and elemental composition. The anti-diabetic effect of Ag–CuO NPs was further investigated utilizing a yeast cell model and amylase inhibition. Here, a decrease in intracellular glucose and a delay in carbohydrate digestion indicate promising antidiabetic action. Furthermore, the prepared nanomaterial showed anticancer potential against the MCF-7 cancer cell line, with an IC ₅₀ value of 11.21 g/ml.     

Thermal radiation impact on magneto-hydrodynamic heat transfer micropolar fluid flow over a vertical moving porous plate: A finite difference approach

For this research, an examination on the magnetohydrodynamic flow of a micropolar fluid across a moving vertical porous plate for the presence of thermal radiation is achieved. It is necessary to translate the partial differential equations regulating the flow, heat, & mass transfer into dimensionless form employing proper non-dimensional variables, which are then cracked numerically by utilizing the Finite difference approach. Graphs are used to represent numerical values of various flow profiles; however, tables are used to represent the simulated values of rate coefficients. The velocity rises when the value of Grashof number, dimensionless viscosity ratio is raised, and the opposite effect is seen when the value of magnetic parameter, micro-gyration factor is raised. The result in skin friction coefficient improves when the values of magnetic parameter, micro-gyration factor, Prandtl number, and radiation are raised higher.