A diagonal splitting method for solving semidiscretized parabolic partial differential equations

In this work, a diagonal splitting idea is presented for solving linear systems of ordinary differential equations. The resulting methods are specially efficient for solving systems which have arisen from semidiscretization of parabolic partial differential equations (PDEs). Unconditional stability of methods for heat equation and advection–diffusion equation is shown in maximum norm. Generalization of the methods in higher dimensions is discussed. Some illustrative examples are presented to show efficiency of the new methods.     

Highly selective transport of lead cation through bulk liquid membrane by macrocyclic ligand of decyl-18-crown-6 as carrier

The liquid membrane transport of Pb²⁺ cation using decyl-18-crown-6 as selective ion carrier was studied. The transport of lead ion across the liquid membrane in the presence of S₂O ₃ ^2? , P₂O ₇ ^4? , CN^?, SCN^?, and DDC^? as stripping agents in the receiving phase shows that the nature and the concentration of the stripping agents affect on Pb²⁺ cation transport and the maximum transport occurs when the sodium thiosulfate (Na₂S₂O₃) was used. The effects of various parameters influencing the transport efficiency such as the pH of the source and receiving phases, the concentration of picrate ion as counter ion in the source phase were also studied. Five replicated experiments show that a value 82.12 ± 2.09% of the initial concentration of the Pb²⁺ cation in the source phase is extracted into the receiving phase after 4 hours. Also the selectivity and efficiency of lead ion transport from the source phase containing equimolar mixtures of Na⁺, K⁺, Ca²⁺, Ni²⁺, Cu²⁺, Cd²⁺ and Ag⁺ metal cations were investigated.     

New ceramides from Platytaenia multicaule

Phytochemical investigation of Platytaenia multicaule resulted in the isolation of two new ceramides, N-triacontylpentadecanamide and 1,3,4-trihydroxy-2,dodecanoylamino-(24E)-unacotenene, along with two known compounds, beta-sitosterol and beta-sitosterol glycoside. The structure elucidation of the isolated compounds was based primarily on 1D and 2D NMR analyses, including COSY, NOESY, HMQC, and HMBC correlations.     

Iodine/potassium iodide catalyst for the synthesis of trifluoromethylated quinazolines via intramolecular cyclization of 2,2,2-trifluoro-N-benzyl-N′-arylacetimidamides

Molecular Diversity - An efficient and simple protocol for the synthesis of trifluoromethylated quinazolines has been described by I2-/KI-promoted oxidative C(sp3)–C(sp2) bond under the...     

The effect of temperature and slice thickness on drying kinetics tomato in the infrared dryer

In this study thin layer drying of tomato slices were investigated in the infrared dryer. Drying rate increased with increasing temperature and reduction thickness and thus reduced the drying time. The effective diffusivity increased with increasing temperature and with increasing thickness of the samples. The effective diffusivity values changed from 1.094 × 10^?9 to 4.468 × 10^?9 m²/s and for activation energy varied from 110 to 120 kJ/mol. The best model for drying process of tomato slices was Midilli model.     

Synthesis and reactions of functionalized spirocyclopropanes by cyclization of dilithiated β-ketosulfones, α-cyanoacetone and diethyl 2-oxopropylphosphonate with 1,1-diacetylcyclopropane

The cyclization of β-ketosulfone, β-ketonitrile and β-ketophosphonate dianions with 1,1-diacetylcyclopropane afforded 1-hydroxyspiro[5.2]cyclooct-4-en-3-ones, which were transformed, by reaction with tetrabutylammonium halides, into functionalized phenols containing a remote halide function.     

Gnapholide: a new guaiac-dimer from Pulicaria gnaphalodes (Asteraceae)

The ethyl acetate soluble part of the chloroform extract of Pulicaria gnaphalodes belonging to the family Asteraceae afforded a new sesquiterpene-dimer of guaiane class named as gnapholide and anabsinthin of the same skeleton. The structures of both the compounds were elucidated with the aid of spectroscopic techniques including 2D NMR.     

Correlation of plasma electron temperature with neutron emission ina low-energy plasma focus

Correlation of neutron emission with plasma electron temperature in a low-energy (2.3 kJ) plasma focus is investigated. To determine the plasma temperature by continuum X-ray analysis, cobalt is selected as the filter, which discriminates the line radiation from the background impurities like carbon, nitrogen, and oxygen, or the copper of which plasma focus electrodes are made. For a pressure range of high neutron emission (1-4 mbar), the neutron yield is found to correlate with the plasma temperature. The highest temperature recorded is 5 keV at 2.5 mbar, the filling pressure for the highest neutron emission in this device     

NaY zeolite functionalized by sulfamic acid/Cu(OAc)2 as a new and reusable heterogeneous hybrid catalyst for efficient solvent-free formylation of amines

NaY zeolite functionalized by sulfamic acid/Cu(OAc)_2[NaY/SA/Cu(Ⅱ)] was synthesized and used as a new,efficient and recyclable catalyst for preparation of formamides. This novel organic-inorganic hybrid catalyst was characterized by several techniques such as FT-IR, XRD, SEM, EDX and TG analysis.Chemoselectivity, easy procedure, excellent yields, very short reaction times, solvent-free and mild reaction conditions are some benefits of this new protocol.