Design,synthesis and liquid crystalline behavior of ethyl 4-((4-alkoxyphenyl)diazenyl)benzoates

A series of ethyl 4-((4-alkoxyphenyl)diazenyl)benzoate is synthesized and the liquid crystalline behavior studied. Synthesized compounds are characterized by FTIR, ¹H-NMR, Mass and single crystal XRD. Differential scanning calorimetry was carried out to study the phase transitions and enthalpy changes. Polarizing optical microscopy revealed the mesogenic properties. These techniques revealed that three compounds (2a, 2b, 2f) exhibit liquid crystalline properties in the range of 80–104°C. POM exhibiting focal conical fan like texture which revealed the presence of smectic phases suggestive of their use in LCD and temperature sensing devices, besides 2c can be used as green emitter in OLEDs.     

Polyaniline Modified CNTs and Graphene Nanocomposite for Removal of Lead and Zinc Metal Ions: Kinetics,Thermodynamics and Desorption Studies

A novel polyaniline-modified CNT and graphene-based nanocomposite (2.32–7.34 nm) was prepared and characterized by spectroscopic methods. The specific surface area was 176 m²/g with 0.232 cm³/g as the specific pore volume. The nanocomposite was used to remove zinc and lead metal ions from water; showing a high removal capacity of 346 and 581 mg/g at pH 6.5. The data followed pseudo-second-order, intraparticle diffusion and Elovich models. Besides this, the experimental values obeyed Langmuir and Temkin isotherms. The results confirmed that the removal of lead and zinc ions occurred in a mixed mode, that is, diffusion absorption and ion exchange between the heterogeneous surface of the sorbent containing active adsorption centers and the solution containing metal ions. The enthalpy values were 149.9 and 158.6 J.mol⁻¹K⁻¹ for zinc and lead metal ions. The negative values of free energies were in the range of −4.97 to −26.3 kJ/mol. These values indicated an endothermic spontaneous removal of metal ions from water. The reported method is useful to remove the zinc and lead metal ions in any water body due to the high removal capacity of nanocomposite at natural pH of 6.5. Moreover, a low dose of 0.005 g per 30 mL made this method economical. Furthermore, a low contact time of 15 min made this method applicable to the removal of the reported metal ions from water in a short time. Briefly, the reported method is highly economical, nature-friendly and fast and can be used to remove the reported metal ions from any water resource.     

Thermal analysis of nanofluid saturated in inclined porous cavity cooled by rotating active cylinder subjected to convective condition

Journal of Thermal Analysis and Calorimetry - Convective heat transfer in a porous cavity conjugated with an active rotating cylinder is investigated in this paper. Copper–water nanofluid...     

A weighted adaptive least-squares finite element method for the Poisson-Boltzmann equation

The finite element methodology has become a standard framework for approximating the solution to the Poisson-Boltzmann equation in many biological applications. In this article, we examine the numerical efficacy of least-squares finite element methods for the linearized form of the equations. In particular, we highlight the utility of a first-order form, noting optimality, control of the flux variables, and flexibility in the formulation, including the choice of elements. We explore the impact of weighting and the choice of elements on conditioning and adaptive refinement. In a series of numerical experiments, we compare the finite element methods when applied to the problem of computing the solvation free energy for realistic molecules of varying size.     

Thin film flow of non‐Newtonian MHD fluid on a vertically moving belt

Thin film flow of an Oldroyd 6‐constant fluid on a vertical moving belt is investigated analytically and numerically. The governing equations for the flow field are derived for a steady one‐dimensional flow. The effect of constant applied magnetic field is included and its influence on the flow field is studied. The nonlinear governing equations are solved analytically and the exact solution is obtained in an elegant way. Numerical solutions are also obtained using higher‐order Chebyshev spectral methods. The influence of various non‐Newtonian parameters, gravitational force and applied magnetic field is investigated. The results showing the effect of gravity, magnetic field and material constants α₁ and α₂ are presented. Copyright © 2010 John Wiley & Sons, Ltd.     

Controlled optical photonic crystal AND gate using nematic liquid crystal layers

Two optical AND gates built in 2D photonic crystal (PhC) platform have been proposed and numerically simulated using 2D finite element method (FEM). The suggested logic gates consist of five PhC waveguides and silicon annular ring resonator filled by nematic liquid crystal (NLC) of type E7. The first proposed AND gate can handle two inputs and support two operating wavelengths, λ = 1.5 and 1.55 µm. However, the second proposed AND gate can handle three inputs at λ = 1.5 µm. The reported logic gates offer high and low transmission levels with a threshold of 0.5 and an ultra-high bit rate of not less than 0.3 Tbits/s. Further, the suggested AND gates operation can be switched off by using the NLC layer.     

Analytical performance study of explosively formed projectiles

Hydrocode simulations are carried out using Ansys Autodyn (version 11.0) to study the effects of the liner material (mild steel, copper, armco iron, tantalum, and aluminum) on the shape, velocity, traveled distance, pressure, internal energy, temperature, divergence or stability, density, compression, and length-to-diameter ratio of explosively formed projectiles. These parameters are determined at the instants of the maximum as well as stable velocity during the flight towards the target. The results of these parameters present the potential capability of each liner material used to fabricate explosively formed projectiles. An experimental analysis is performed to study the velocity status and the length-to-diameter ratio of explosively formed projectiles.     

Extension of the Taylor Equation for Oil-Water-Surfactant System and Investigating the Impact of Surfactant Concentration over the Quality of Emulsion

Emulsions stand among the most important multiphase fluids, exhibiting various complicated phenomenon. To understand the process of emulsification, the Taylor equation has been extended to incorporate the parameters that depend on molecular mass of oil and their contents and the amount of surfactant added. To test the validity of the proposed equations, four well-defined short chain (n-hexane, n-heptane, n-decane, and kerosene) oils were emulsified in water and the results were compared with the experimental ones. It has been concluded that the extended Taylor equation worked well, even in the presence of surfactant. The quality of the emulsion defined and discussed in terms of size and number of droplets was best near CMC of the surfactant used. A relationship has also been derived between CMC of surfactant and its distribution coefficient, which allows the exact value of one parameter to be determined if other is known.     

Pregnane derivatives from Potentilla evestita

A new pregnane derivative, 2,6beta,7beta-trihydroxy-4-methyl-19-norpregna-1,3,5(10)-trien-17-one, has been isolated from the ethyl acetate soluble fraction of Potentilla evestita along with a pregnane derivative, 11alpha,17alpha,21-trihydroxypregna-4,16(22)-diene-3,20-dione, that is reported for the first time as a natural product. Their structures were elucidated with the aid of 1H and 13C NMR spectra and by COSY, HMQC, HMBC and NOESY experiments.