Effect of monomer-treated inorganic fillers on mechanical,rheological, and thermal properties of LLDPE nanocomposites

This article discusses the role of nanoscale calcium carbonate (nCC) surface treatment in affecting the mechanical, rheological, and thermal properties of linear low-density polyethylene (LLDPE). The mechanical tests indicated that nCC could simultaneously reinforce and toughen LLDPE. In addition, the composite sample with methacrylic acid (MA)-treated nanoparticles shows further increased mechanical properties as compared to unmodified nanoparticles. In the presence of dicumyl peroxide (DCP), a small amount of MA could increase markedly the mechanical properties of LLDPE/nCC composites. The results of rheological property analysis indicated that the viscosity increased with increasing amount of the filler, especially at low shear rates, but showed a substantial reduction with increasing concentration of the reactive monomer. The thermal behavior of these materials is evaluated by differential scanning calorimetry and thermogravimetric analysis. The addition of a small amount of MA and DCP enhances the stabilization of the blends.     

Square-root dynamics of a giving up smoking model

The paper presents a new giving up smoking model for which interaction term is square root of potential and occasional smokers of model presented in Zaman (2011) [15]. First, we will show formulation of the model. Then we will discuss local and global stability of the model and its general solutions. The non-standard finite difference method (NSFD) is used to solve the new giving up smoking model. Both non-negativity and conservative law for differential equations system are discussed. Numerical results are presented graphically and compared well with those obtained by Runge–Kutta fourth-order method (RK4) and ODE45.     

Silabenzene through divalent precursors at theoretical levels

Abstract  Based on geometries and relative energies, three different mechanisms are proposed for the rearrangements of five isomers of silacyclohexadienylidenes to silabenzene at B3LYP and MP2 levels: (1) [1,2]-hydrogen migration through a planar transition state, (2) [1,4]-hydrogen migration through a boat transition state, and (3) zip-zap mechanism, comprised of three successive [1,2]-hydrogen migrations. The above results are compared and contrasted to rearrangements of the corresponding cyclohexadienylidenes to benzene. Graphical abstract   Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis, structural elucidation and X-ray analysis of triphenyltin(IV) [2-(2,3-dimethylanilino)nicotinate]

Triphenyltin(IV) [2-(2,3-dimethylanilino)nicotinate] was prepared by the interaction of triphenyltin(IV) hydroxide and 2-(2,3-dimethylanilino)nicotinic acid in 1:1 ratio. This compound was characterized by elemental analyses, IR, multinuclear NMR spectroscopy (¹H and ¹³C) and mass spectrometry. The structure of title compound was confirmed by single crystal X-ray crystallography. The coordination around the tin atom was studied both in solution and solid state. The geometry around tin is trigonal bipyramidal in solid state while it is tetrahedral in solution. The compound belongs to Monoclinic system, having space group P 21/c with unit cell dimensions a = 17.002(8) Å, b = 9.0793(3) Å, c = 18.2616(9) Å, α = 90 (°) β = 107.381(4) (°), γ = 90 (°).     

Thermally stratified flow of hybrid nanofluids with radiative heat transport and slip mechanism: multiple solutions

Research on flow and heat transfer of hybrid nanofluids has gained great significance due to their efficient heat transfer capabilities.In fact,hybrid nanofluids are a novel type of fluid designed to enhance heat transfer rate and have a wide range of engineering and industrial applications.Motivated by this evolution,a theoretical analysis is performed to explore the flow and heat transport characteristics of Cu/Al₂O₃ hybrid nanofluids driven by a stretching/shrinking geometry.Further,this work focuses on the physical impacts of thermal stratification as well as thermal radiation during hybrid nanofluid flow in the presence of a velocity slip mechanism.The mathematical modelling incorporates the basic conservation laws and Boussinesq approximations.This formulation gives a system of governing partial differential equations which are later reduced into ordinary differential equations via dimensionless variables.An efficient numerical solver,known as bvp4c in MATLAB,is utilized to acquire multiple(upper and lower)numerical solutions in the case of shrinking flow.The computed results are presented in the form of flow and temperature fields.The most significant findings acquired from the current study suggest that multiple solutions exist only in the case of a shrinking surface until a critical/turning point.Moreover,solutions are unavailable beyond this turning point,indicating flow separation.It is found that the fluid temperature has been impressively enhanced by a higher nanoparticle volume fraction for both solutions.On the other hand,the outcomes disclose that the wall shear stress is reduced with higher magnetic field in the case of the second solution.The simulation outcomes are in excellent agreement with earlier research,with a relative error of less than 1%.     

The role of Rho GTPases in the regulation of the rearrangement of actin cytoskeleton and cell movement

The rearrangement of the actin cytoskeleton has been shown to play a critical role in the development of transformation and malignant phenotype of cancer cells. Rho family GTPases regulate the arrangement of the actin cytoskeleton. By wound-healing assay, we have found that NIH 3T3 fibroblast cells move towards the wound- gaps by extending filopodial and lamellipdial structures at the leading edge of the moving cells. We have inactivated the function of Rho GTPases of v-Ras transformed NIH 3T3 cells by overexpressing Rho GTPase-activating (RhoGAP) domain of RhoGAP of p190. We have observed that inactivation of Rho, Rac and Cdc42 GTPases by overexpressing RHG causes inhibition of: (i) polymerization of actin to form filaments, (ii) formation of lamellipodia, filopodia and stress fibres, (iii) cell motility, (iv) cell spreading and (v) cell-to-cell adhesions. These results further strengthen the current knowledge on the role of Rho, Rac and Cdc42 GTPases in the regulation of the rearrangement of actin cytoskeleton. Our results, for the first time, demonstrate that RhoGAP domain of RhoGAP could be used to study the molecular mechanism of Ras-mediated signalling in growth, differentiation and carcinogenesis.     

Trace element composition of blood in adult population in Bangladesh

The trace element composition of whole blood has been investigated in adult population in Bangladesh. The population was formed of one hundred individuals randomly selected from a working community of five hundred adults. The blood samples were freeze dried and analyzed using the external beam PIXE method. In this analysis, proton beams of 2 MeV energy and about 30 nA current were used for characteristic X-ray excitation. The concentration of eight elements, K, Ca, Fe, Cu, Zn, Br, Rb and Pb were determined by comparison with a calibration obtained from NBS orchard leaves. The frequency distributions of all the elements measured are presented and the results are compared with available data. This work was supported in part by the International Atomic Energy Agency, Vienna.     

The morphology and thermal properties of liquid natural rubber (LNR)-compatibilized 60/40 NR/LLDPE blends

The effects of LNR as a compatibilizer in binary blends of 60/40 NR/LLDPE have been investigated by means of differential scanning calorimetry, dynamic mechanical analysis and scanning electron microscopy. Special emphasis was given to the role of LNR in inducing interactions between NR and LLDPE. It has been observed that increasing LNR content decreases T_m and ΔH_f which are indicators of the crystalline part of the blends. The decrease reflects a reduction in the degree of crystallinity which is due to the interference in the form of NR dissolution into the LLDPE phase. The phenomenon leads to a shift in T_g of the amorphous part of LLDPE to higher temperatures as observed by DMA thermograms. The dissolution effect creates better interactions between the phases leading to improvements in the compatibility of the blends. Further confirmation was obtained through SEM examination.