1,866 research outputs found

    Two-parameter differential calculus on the h-superplane

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    We introduce a noncommutative differential calculus on the two-parameter hh-superplane via a contraction of the (p,q)-superplane. We manifestly show that the differential calculus is covariant under GLh1,h2(1∣1)GL_{h_1,h_2}(1| 1) transformations. We also give a two-parameter deformation of the (1+1)-dimensional phase space algebra.Comment: 14 page

    Cartan calculi on the quantum superplane

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    Cartan calculi on the extended quantum superplane are given. To this end, the noncommutative differential calculus on the extended quantum superplane is extended by introducing inner derivations and Lie derivatives

    Numerical Investigation of Ohmic Heating in Channel Flow

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    Heat generation by direct electric conduction (ohmic heating) in a fully developed channel flow was studied to evaluate interaction between the hydrodynamic, electric and the thermal phenomena involved under the effect of natural convection. The equations governing the system were solved numerically by CFD finite volume code (FLUENT6.1 software package). The velocity profiles accelerate more near the wall than at the center that makes the temperature distribution uniform in the channel span. The numerical model is validated with an earlier experimental study [El Moctar et all. 1996] and yielded good agreement

    EFFECT OF NATURAL AND SYNTHETIC POLYMERS ON THE PROPERTIES OF CANDESARTAN CILEXETIL MATRIX TABLET PREPARED BY DRY GRANULATION

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    ABSTRACTObjective: The objective of this study is to develop a controlled release matrix tablet of candesartan cilexetil to reduce the frequency of administration,enhance bioavailability and improve patient compliance; a once daily sustained release formulation of candesartan cilexetil is desirable.Methods: The prepared tablets from F1 to F24 were evaluated with different evaluation parameters like weight variation, drug content, friability,hardness, thickness and swelling ability. In vitro release for all formulas were studied depends on the type and amount of each polymer, i.e. (16 mg,32 mg and 48 mg) respectively beside to the combination effect of polymers on the release of the drug from the tablet.Results: In vitro release showed that formula 13 had the faster release (100% after 4 h) which contained acacia (1:1) and the lowest sustain releasewas showed for F7 (73% after 8 h) which contained HPMC K100M (1:1). Formula 1 was an 89 % release after 8 h which contain eudragit RS100; F4was a 100 % release after 5 h which contain Na CMC, F10 was a 100% after 8 h which contain xanthan gum and F16 was a 100 % release after 5 hwhich contain tragacanth polymer. Formula 9 had a lower release than F7 and F8 respectively. Formula 7 can be used for sustain oral drug delivery ofcandesartan cilexetil while Formula 13 can be used in contrary as fast release tablets for faster response.Conclusion: Controlled drug delivery system is promising for less dosing and higher patient compliance.Keywords: Angiotensin II receptor antagonist, Hypertension, Matrix system, Control release

    Synthesis, Characterization, Thermal Analysis and Structural Studies of New Complexes with Tetradentate Ligand

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    Some new complexes of 4-(5-(1,5-dimethyl-3-oxo-2-phenyl pyrazolidin-4- ylimino)-3,3-dimethyl cyclohexylideneamino) -1,5- dimethyl-2- phenyl -1H- pyrazol -3(2H) –one (L) with Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Pd(II), Re(V) and Pt(IV) were prepared. The ligand and its metal complexes were characterized by phisco- chemical spectroscopic techniques. The spectral data were suggested that the (L) as a neutral tetradentate ligand is coordinated with the metal ions through two nitrogen and two oxygen atoms. These studies revealed Octahedral geometries for all metal complexes, except square planar for Pd(II) complex. Moreover, the thermodynamic activation parameters, such as ?E*, ?H, ?S, ?G and K are calculated from the TGA curves using Coats –Redfern method. Hyper Chem -8 program has been used to predict structural geometries for compounds in gas phase. The heat of formation (?Hf) and bin ding energy (?Eb) at 298 °K for the free ligand and its metal complexes were calculated by PM3 method. The synthesized ligands and their metal complexes were screened for their biological activity against bacterial species, two Gram positive bacteria (Bacillus subtilis and Staphylococcus aureus) and two Gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa)

    Role of phosphoric acid on the corrosion performance of Pb-1.7%Sb gridof lead-acid batteries

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    The corrosion behavior of a commercial Pb-1.7% Sb gridof lead-acid batteries under open circuit conditions in 5M H 2SO4 in the presence of phosphoric acid is studiedby electrochemical impedance spectroscopy and cyclicvoltammetry. Dependence of corrodibility of the alloy onH 3PO4 concentration is weak up to 0.7M. After days ofcorrosion, the corrosion rate in the presence of H 3PO4 isslightly higher than in its absence, due to retardation of the growth of an insulating PbSO 4 layer that acts as an effective diffusion barrier of the corrosive species. The electronic and diffusion properties of the passive layer formed in the presence of H 3PO4 are substantially inferior. Cyclic voltammetry indicates a decrease in amounts of PbSO 4 and Sb 2O3 formed in the presence of H3PO4 and with increasing its concentration. Also, the amount of PbO formed beneath the PbSO 4 layer increases with increasing H3PO4 concentration on the expense of the amount of PbSO 4

    Ultra-fast sampling of terahertz pulses from a quantum cascade laser using superconducting antenna-coupled NbN and YBCO detectors

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    We demonstrate the ultra-fast detection of terahertz pulses from a quantum cascade laser (QCL) using superconducting NbN and YBCO detectors. This has enabled both the intrapulse and interpulse dynamics of a THz QCL to be measured directly, including interpulse heating effects on sub-μs timescales

    h-deformation of Gr(2)

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    The hh-deformation of functions on the Grassmann matrix group Gr(2)Gr(2) is presented via a contraction of Grq(2)Gr_q(2). As an interesting point, we have seen that, in the case of the hh-deformation, both R-matrices of GLh(2)GL_h(2) and Grh(2)Gr_h(2) are the same
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