Carboxyketenes from 4-hydroxy-1,3-oxazin-6-ones and Meldrum's acid derivatives

New 4-hydroxy-1,3-oxazin-6-ones 8 and 16 were prepared from chlorocarbonyl(phenyl)ketene and amides. The flash vacuum thermolysis (FVT) reactions of these compounds and the 4-methoxy derivative 17 were investigated by Ar matrix isolation IR spectroscopy and online mass spectrometry including MS/MS analysis. Carboxy(phenyl)ketene 10 is formed as the major product by thermal fragmentation of 4-hydroxy-1,3-oxazin-6-one 8. This takes place via the unstable 6-hydroxy tautomer 9. Another tautomer, the 5H-isomer 12, leads to the formation of benzoyl isocyanate 13 as a minor product together with phenylketene 14. Carboxy(phenyl)ketene 10 remains detectable at high FVT temperatures but undergoes thermal decarboxylation to phenylketene 14. The same carboxy(phenyl)ketene 10 is also produced in significant amounts by FVT of 5-phenyl-Meldrum's acid 18 via the unstable enol tautomer 19. A small amount of the unsubstituted carboxyketene 20 is observable on FVT of Meldrum's acid 1 itself.     

Chemical composition of the essential oil of Pelargonium quercetorum Agnew. of Iran

The volatile constituents in the essential oil of Pelargonium quercetorum Agnew., growing wild in Kurdistan, Iran were investigated through GC and GC/MS technique. Twenty-six compounds, representing 21 (80.77%) of the total oil were identified. The main components were: alpha-pinene (25.28%), alpha-fenchyl acetate (20.63%), limonene (9.94%), beta-caryophyllene (8.20%), camphene (4.31%), delta-cadinene (3.32%), beta-pinene (3.21%), alpha-amorphene (2.80%), valencene (2.73%), ledene (2.25%) and p-cymene (1.63%).     

Effect of CO2 laser radiation on the surface properties of polyethylene terephthalate

The surfaces of polyethylene terephthalate (PET) obtained by irradiation with a CO₂ pulsed laser in air were studied. The complicated microstructures using various laser wavelengths were observed by scanning electron microscopy (SEM). The changes in chemical and physical properties of the irradiated PET surface were investigated by attenuated total reflectance infrared spectroscopy (ATR-FTIR) and contact angle measurements. ATR-IR spectrum showed that the crystallinity in the surface region decreased due to laser irradiation. The water drop contact angle also decreased with increasing of laser pulses. The density of peroxides formed on the irradiated PET surface were determined by iodide method.     

Filamentation “remote” sensing of chemical and biological agents/pollutants using only one femtosecond laser source

All matters in the path of filaments induced by an intense femtosecond laser pulse propagating in air could be fragmented and result in the emission of characteristic fluorescence spectra from the excited fragments. The fluorescence spectra exhibit specific signatures (fingerprints) that can be used for the identification of various substances including chemical and biological species. In this paper, we present an overview of the recent progress in our laboratory concerning the “remote” sensing of chemical and biological agents/pollutants in air using filamentation-induced nonlinear fluorescence techniques.     

HPTLC Analysis of Tamoxifen Citrate in Drug-Release Media During Development of an In-Situ-Cross-Linking Delivery System

JPC – Journal of Planar Chromatography – Modern TLC - High-performance liquid chromatography (HPLC) has been the most popular choice for analysis of tamoxifen citrate. In this study,...     

Density and viscosity of 1-butyl-3-methylimidazolium nitrate with ethanol, 1-propanol, or 1-butanol at several temperatures

Densities and viscosities of 1-butyl-3-methylimidazolium nitrate [Bmim][NO₃], and its binaries with alcohol (ethanol, 1-propanol, or 1-butanol) were measured at different temperatures. The densities and viscosities of pure ionic liquid were correlated successfully by empirical equations. The Vogel–Fulcher–Tammann equations can fit the experimental data of viscosities for pure IL. Excess molar volume and viscosity deviations were calculated for the binaries. The excess molar volumes have negative deviations from the ideal solution.     

A chaotic secure communication scheme using fractional chaotic systems based on an extended fractional Kalman filter

In recent years chaotic secure communication and chaos synchronization have received ever increasing attention. In this paper, for the first time, a fractional chaotic communication method using an extended fractional Kalman filter is presented. The chaotic synchronization is implemented by the EFKF design in the presence of channel additive noise and processing noise. Encoding chaotic communication achieves a satisfactory, typical secure communication scheme. In the proposed system, security is enhanced based on spreading the signal in frequency and encrypting it in time domain. In this paper, the main advantages of using fractional order systems, increasing nonlinearity and spreading the power spectrum are highlighted. To illustrate the effectiveness of the proposed scheme, a numerical example based on the fractional Lorenz dynamical system is presented and the results are compared to the integer Lorenz system.     

Investigation of the effects of two parallel wires' non-uniform magnetic field on heat and biomagnetic fluid flow in an aneurysm

ABSTRACT

In this paper, effects of two wires magnetic field on heat transfer and biomagnetic fluid flow in an aneurysm have been investigated using the ferrohydrodynamics model. Using the finite volume method and the SIMPLE algorithm, the governing equations have been discretised. Simulations have been carried out for both conditions of wires in the same and opposite directions and different magnetic numbers of 41 and 82. Results show that the magnetic field causes a decrease in heat transfer of blood flow towards the walls. Moreover, major energy loss or pressure drop, arising from mean wall shear stress, decreases but local or minor energy loss, arising from aneurysm vortexes, increases. Furthermore, risk factors of aneurysm rupture is decreased under the effect of the magnetic field. The effective contact surface between drug-coated magnetic nanoparticles and the aneurysm tissue may increase and residence time of drug on the cells of the region would decrease.