Identification and Separation of Lead (II), Nickel (II), and Cobalt (II) on Silica Gel 60 F254 High-Performance Thin-Layer Chromatographic Plates with Mixed Aqueous Sodium Dodecyl Sulfate—Oxalic Acid Solvent System

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic separation of three metal cations was performed on high-performance thin-layer plates (silica gel 60F254) with...     

Growth properties of the q-Dunkl transform in the space $$L^{p}_{q,\alpha }({\mathbb {R}}_{q},|x|^{2\alpha +1}d_{q}x)$$ L q , α p ( R q , | x | 2 α + 1 d q x )

The Ramanujan Journal - Our aim in this work is to prove an analogue of Titchmarsh’s theorem [19, Theorem 84] and Younis’s theorem [20, Theorem 3.3] on the image under the q-Dunkl...     

Fundamental solution of generalized thermo-viscoelasticity using the finite element method

The present paper is aimed at an investigation of the temperature, displacement, and stress in a viscoelastic half space of Kelven–Voigt type. The formulation is applied according to three theories of generalized thermoelasticity: Lord–Shulman with one relaxation time, Green–Lindsay with two relaxation times, as well as the coupled theory. The nondimensional governing equations are solved by the finite element method. Numerical results for the temperature distribution, displacement, and thermal stress are represented graphically. Comparisons are made with the results predicted by the CD, L-S, and G-L theories in the presence and absence of the viscoelastic relaxation time.     

Simulated fractal permeability for porous membranes

Fractal permeability model for bi-dispersed porous media is developed based on the fractal characteristics of pores in the membrane. The fractal permeability model is found to be a function of the tortuosity fractal dimension, pore area fractal dimension, sizes of particles and clusters, micro-porosity inside clusters, and the effective porosity of a medium. The pore area fractal dimension and the tortuosity fractal dimension of the porous membranes are determined by the box counting method. To verify the validity of the model, the predicted permeability were compared with the experimental data utilizing H₂ gas permeating through porous Pd-alumina, silicalite-1 and B-ZSM-5, and O₂ across perovskite-alumina membranes form the past effort.     

Sard's theorem for mappings in Hölder and Sobolev spaces

We prove various generalizations of classical Sard's theorem to mappings f:M ^m →N ⁿ between manifolds in Hölder and Sobolev classes. It turns out that if f ∈ C ^k,λ (M ^m ,N ⁿ ), then—for arbitrary k and λ—one can obtain estimates of the Hausdorff measure of the set of critical points in a typical level set f ^?1(y). The classical theorem of Sard holds true for f ∈ C ^k with sufficiently large k, i.e., k>max(m?n,0); our estimates contain Sard's theorem (and improvements due to Dubovitskii and Bates) as special cases. For Sobolev mappings between manifolds, we describe the structure of f ^?1(y).     

A topological characterization of the goldman prime spectrum of a commutative ring

A prime ideal p of a commutative ring R is said to be a Goldman ideal (or a G-ideal) if there exists a maximal ideal M of the polynomial ring R[X] such that p = M ∩ R. A topological space is said to be goldspectral if it is homeomorphic to the space Gold(R) of G-ideals of R (Gold(R) is considered as a subspace of the prime spectrum Spec(R) equipped with the Zariski topology). We give here a topological characterization of goldspectral spaces.     

Viscoelastic behaviour of ferro- and antiferroelectric phases

We have investigated the viscoelastic behaviour exhibited by chiral smectic C* phases in homeotropic orientation. For an appropriate scattering geometry and using the light scattering technique, the orientational diffusivities associated with the Goldsone mode in ferro- and antiferroelectric phases of C₁₁thiobenzoate and C₈tolane compounds have been measured. (SmC_A*) is about 100 times weaker than (SmC*). This divergence may be largely attributed to the mode of the molecular arrangement in ferro- and antiferroelectric phases, in spite of the same helical structure observed in the two phases.     

A new synthesis of vitamin C

l-Arabinose was reduced to l-arabinitol and condensed with formaldehyde to give two bis(di-0-methylene-l-arabityloxymethane and two di-O-methylene-l-arabinitol derivatives. Cis-fused 1,3:2,4-Di-O-methylene-l-arabinitol and trans-fused 2,4:3,5-Di-O-methylene-l-arabinitol were also isolated; only the former was affected by the oxidation to give the corresponding aldehyde, which was converted successively to the hydroxy amide, the ethyl hydroxy ester, the corresponding keto ester and vitamin C.