Composite polymeric electrolytes based on PMMA-LiCF3SO3-SiO2

Preliminary results on the mechanical, optical and electrical properties of composite gel electrolytes (CGEs) with fumed silica (SiO₂) as a filler added to gel polymeric electrolyte (GPE) based on PMMA, LiCF₃SO₃ and PC are presented in this paper. Added fumed silica is seen to enhance the mechanical properties of the GPE without changing the conductivity significantly. The high ionic conductivity (×10⁻³ S/cm), high transmission in the visible region and nominal variance of conductivity and viscosity over a wide temperature window show that these CGEs are potential electrolytes for electrochromic windows (ECWs).     

Teleparallel versions of Friedmann and Lewis–Papapetrou spacetimes

This paper is devoted to investigating the teleparallel versions of the Friedmann models as well as the Lewis–Papapetrou solution. We obtain the tetrad and the torsion fields for both spacetimes. It is shown that the axial-vector vanishes for the Friedmann models. We discuss the different possibilities for the axial-vector, depending on the arbitrary functions ω and ψ in the Lewis–Papapetrou metric. The vector related to spin has also been evaluated.     

Symmetries of Energy-Momentum Tensor： Some Basic Facts

It has been pointed out by Hall et al. [Gen. Rel. Gray. 28 （1996） 299.] that matter collineations can be defined by using three different methods. But there arises the question whether one studies matter collineations by using LεTab=0, or LεT^ab = 0 or LεT^b a=0. These alternative conditions are, of. course, not generally equivalent. This problem has been explored by applying these three definitions to general static spherically symmetric spacetimes. We compare the results with each definition.     

Rate and Computational Studies for Pd-NHC-Catalyzed Amination with Primary Alkylamines and Secondary Anilines: Rationalizing Selectivity for Monoarylation versus Diarylation with NHC Ligands

The relative rates of arylation of primary alkylamines with different Pd-NHC catalysts have been measured, as have the relative rates of arylation of the secondary aniline product in an attempt to understand the key ligand design features necessary to have high selectivity for the monoarylated amine product. As the substituents on the N-aryl ring of the NHC increase in size, selectivity for monoarylation increases and this is further enhanced by chlorinating the back of the NHC ring. Computations have been performed on the catalytic cycle of this transformation in order to understand the selectivity obtained with the different catalysts.     

Regression and ANN models for estimating minimum value of machining performance

Surface roughness is one of the most common performance measurements in machining process and an effective parameter in representing the quality of machined surface. The minimization of the machining performance measurement such as surface roughness (R_a) must be formulated in the standard mathematical model. To predict the minimum R_a value, the process of modeling is taken in this study. The developed model deals with real experimental data of the R_a in the end milling machining process. Two modeling approaches, regression and Artificial Neural Network (ANN), are applied to predict the minimum R_a value. The results show that regression and ANN models have reduced the minimum R_a value of real experimental data by about 1.57% and 1.05%, respectively.     

Studies on Melamine Modified Polyesteramide as Anticorrosive Coatings from Linseed Oil: A Sustainable Resource

Melamine modified polyester amide (MPEA) was synthesized by the reaction of linseed oil fatty amide. The resin was further cured at room temperature by polystyrene co‐maleic anhydride (SMA) in different phr (30–80) to obtain MPEA coatings. The probable structure of MPEA was confirmed by FT‐IR, ¹H‐NMR and ¹³C‐NMR spectroscopic techniques. The physico‐chemical characterization of these resins viz. iodine value, saponification value, refractive index, inherent viscosity were carried out by standard methods. MPEA (40 wt%) solution in ethylene glycol monomethyl ether (EGME) was applied on a mild steel strip of standard sizes to study their physico‐mechanical and chemical resistance properties. It was found that coatings of MPEA with 60 parts per hundred of the resin (phr) of SMA showed the best performance in physico‐mechanical and alkali resistance properties. Thermal stability and curing behavior were studied by Thermo Gravimetric Analyses (TGA) and Differential Scanning Calorimetry (DSC), respectively.