Frequency spectrum of toroidal Alfv\'en mode in a neutron star with Ferraro's form of nonhomogeneous poloidal magnetic field

Using the energy variational method of magneto-solid-mechanical theory of a perfectly conducting elastic medium threaded by magnetic field, the frequency spectrum of Lorentz-force-driven global torsional nodeless vibrations of a neutron star with Ferraro's form of axisymmetric poloidal nonhomogeneous internal and dipole-like external magnetic field is obtained and compared with that for this toroidal Alfv\'en mode in a neutron star with homogeneous internal and dipolar external magnetic field. The relevance of considered asteroseismic models to quasi-periodic oscillations of the X-ray flux during the ultra powerful outbursts of SGR 1806-20 and SGR 1900+14 is discussed.Comment: Accepted for publication in Astrophysics & Space Scienc

Synthesis of Lewis A and Lewis X pentasaccharides based on N-trichloroethoxycarbonyl protection

Thexyldimethylsilyl 4,6-O-benzylidene-2-deoxy-2-trichloroethoxycarbonylamino-beta-D-glucopyranoside (4), having the 3-hydroxy group unprotected, is a versatile starting material for the synthesis of glucosamine containing oligosaccharides. Thus, reaction with galactosyl donor 5 or fucosyl donor 6 afforded the desired beta(1-3)- and alpha(1-3)-linked disaccharides 7 and 8, respectively, in high yields, Reductive opening of the benzylidene moieties in 7 and 8 gave access to the 4-hydroxy groups in 9 and 10. Ensuing fucosylation of 9 or galactosylation of 10 led to Lewis A (Le(a)) and Lewis X (Le(x)) trisaccharide building blocks 13 and 14, respectively. Their transformation into glycosyl donors 19 and 20 and subsequent reaction with 3b-O-unprotected lactose derivative 23 as acceptor furnished the Le(a)- and Le(x) pentasaccharide precursors 24 and 25. Exchange of the N-trichloroethoxycarbonyl group for an N-acetyl group and removal of the O-benzyl and O-acetyl protective groups afforded the desired Le(a)- and Lex-pentasaccharides 1 and 2

Characterization of Hemp (Cannabis sativa L.) Biodiesel Blends with Euro Diesel, Butanol and Diethyl Ether Using FT-IR, UV–Vis, TGA and DSC Techniques

Blending biodiesel&ndash;diesel blends with alternative fuels such as butanol and diethyl ether becomes an interesting area of research. Butanol is becoming a popular fuel due to its renewable nature and superior properties compared to ethanol. Diethyl ether can be considered as a renewable fuel as it can be produced from bioethanol through easy dehydration process. This paper aims to study the physicochemical properties of biodiesel produced from Hemp (Cannabis sativa&nbsp;L.) and its blends with Euro diesel, butanol and diethyl ether. Furthermore, characterizations such as DSC, FT-IR, UV&ndash;Vis and TGA were also analyzed. Most of the properties of biodiesel satisfy EN 14214 and ASTM D6751 standards except iodine value and oxidation stability due to the high degree of unsaturation (128.549). Blending of hemp biodiesel with Euro diesel, butanol and diethyl ether improved the cold flow properties, kinematic viscosity and density. However, flash point decreased dramatically specially when blending with diethyl ether due to its low flash point. Therefore, care should be taken when handling or transporting biodiesel&ndash;diesel&ndash;diethyl ether blends. This work supports that blending Hemp methyl ester with Euro diesel, butanol and diethyl ether as ternary blends (up to 20%) can be considered as alternatives to fossil diesel in CI diesel engines. Therefore, it is recommended that engine, emissions and combustion characteristics of all blends shall be further investigated.</p