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Microwave Technology (microwave + technology)
Selected AbstractsTransition Metal Catalyzed Cross-Coupling of Aryl Grignard Reagents with Aryl Fluorides via Pd- or Ni-Activation of the C,F Bond: An Efficient Synthesis of Unsymmetrical Biaryls , Application of Microwave Technology in Ligand and Catalyst Screening.CHEMINFORM, Issue 27 2005John W. Dankwardt Abstract For Abstract see ChemInform Abstract in Full Text. [source] Neat Reaction Microwave Technology for the Synthesis of N-Substituted-1,4-dihydropyridines.CHEMINFORM, Issue 32 2004Mazaahir Kidwai Abstract For Abstract see ChemInform Abstract in Full Text. [source] A new parallelization strategy for solving time-dependent 3D Maxwell equations using a high-order accurate compact implicit scheme,INTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 5 2006Eugene Kashdan Abstract With progress in computer technology there has been renewed interest in a time-dependent approach to solving Maxwell equations. The commonly used Yee algorithm (an explicit central difference scheme for approximation of spatial derivatives coupled with the Leapfrog scheme for approximation of temporal derivatives) yields only a second-order of accuracy. On the other hand, an increasing number of industrial applications, especially in optic and microwave technology, demands high-order accurate numerical modelling. The standard way to increase accuracy of the finite difference scheme without increasing the differential stencil is to replace a 2nd-order accurate explicit scheme for approximation of spatial derivatives with the 4th-order accurate compact implicit scheme. In general, such a replacement requires additional memory resources and slows the computations. However, the curl-based form of Maxwell equations allows us to construct an effective parallel algorithm with the alternating domain decomposition (ADD) minimizing the communication time. We present a new parallel approach to the solution of three-dimensional time-dependent Maxwell equations and provide a theoretical and experimental analysis of its performance. Copyright © 2006 John Wiley & Sons, Ltd. [source] Separation and recovery of cellulose and lignin using ionic liquids: a process for recovery from paper-based wasteJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2009Huma Lateef Abstract BACKGROUND: The production of paper makes use of cellulose and lignin as a raw material, and almost all cellulose and lignin production comes from raw wood materials, contributing to deforestation and resulting in potential environmental harm. It is therefore beneficial to develop technologies for cellulose and lignin recovery for re-use and sustainability of resources. RESULTS: Three imidazolium based ionic liquids (ILs), 1-(2-cyanoethyl)-3-methylimidazolium bromide (cyanoMIMBr), 1-propyl-3-methylimidazolium bromide (propylMIMBr) and 1-butyl-3-methylimidazolium chloride (butylMIMCl), were synthesised by microwave technology and fully characterised by mass spectrometry, thermogravimetric differential scanning calorimetry, thin layer chromatography, nuclear magnetic resonance and Fourier transform infrared spectroscopies. Cellulose and lignin were soluble in all three ILs with solubility being greatest in cyanoMIMBr. Regeneration of cellulose and lignin was achieved from saturated solutions of cellulose in IL and lignin in IL for all three ILs. The ILs propylMIMBr and butylMIMBr have been used for the first time in the separation and recovery of cellulose and lignin and regeneration of the IL from a mixture of cellulose and lignin in IL. FTIR analysis confirms successful recovery. CONCLUSIONS: This work demonstrates the ability of ILs to separate and recover cellulose and lignin from a mixed system. Copyright © 2009 Society of Chemical Industry [source] Ionic liquids in the selective recovery of fat from composite foodstuffsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 11 2009Huma Lateef Abstract BACKGROUND: Ionic liquids (ILs) are able to dissolve a wide range of organic and inorganic molecules and have potential application in the separation and recovery of valuable components from wastes. The potential for ILs to separate sugar and fat from food waste is demonstrated using chocolate as a model system. RESULTS: The ILs 1-(2-cyanoethyl)-3-methylimidazolium bromide (cyanoMIMBr), 1-propyl-3-methylimidazolium bromide (propylMIMBr), 1-hexylpyridinium bromide (hexylPyrBr) and 1-butyl-3-methylimidazolium chloride (butylMIMCl) were synthesised by microwave technology and fully characterised by mass spectrometry, thermogravimetric differential scanning calorimetery, thin layer chromatography, nuclear magnetic resonance and Fourier transform infrared spectroscopy. The solubilities of the fat and carbohydrate components in the ILs are reported for the two main ingredients in chocolate. CyanoMIMBr and propylMIMBr selectively solubilise sugar leaving the fat insoluble. Both cyanoMIMBr and propylMIMBr have been used to successfully separate sugars and cocoa butter fat from white, milk and dark chocolate and the Fourier transform infrared spectra and thermogravimetric differential scanning calorimeter profiles of the extracted fat samples are in good agreement with reference material data. CONCLUSIONS: The ILs cyanoMIMBr and propylMIMBr are successful in the separation and recovery of fat from white, milk and dark chocolate, as confirmed by FTIR and TG-DSC data. Copyright © 2009 Society of Chemical Industry [source] A pulsed confocal microwave technique for the detection of dielectric contrast of breast tissueMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2005G. Bindu Abstract Confocal microwave technology is explored as a screening tool to detect regions of dielectric contrast in breast tissue. When exposed to microwaves, malignant breast tissue exhibits electrical properties that are significantly different from that of healthy breast tissue. In vitro studies of normal and cancerous samples of breast tissue are performed using a prototype of confocal microwave imaging. Experimentally obtained time-domain results are substantiated by finite-difference time-domain (FDTD) analysis. Dielectric permittivities of the samples are estimated from the experimentally obtained time-domain results and are validated by subjecting the samples to dielectric studies using a cavity-perturbation technique. The results are compared with the dielectric parameters of in vitro breast tissue data available in literature. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 209,212, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21125 [source] Microwave-assisted synthesis, spectroscopy and biological aspects of binuclear titanocene chelates of isatin-2,3-bis(thiosemicarbazones)APPLIED ORGANOMETALLIC CHEMISTRY, Issue 1 2009Priyanka Banerjee Abstract The reactions of bis(cyclopentadienyl)titanium(IV) chloride with a new class of bis(thiosemicarbazones) (H2L), derived by condensing isatin with different N(4)-substituted thiosemicarbazides, have been studied both by a conventional stirring method and also using microwave technology. Binuclear products of type [{(,5 -C5H5)2TiCl} 2(L)] have been isolated in both cases. Tentative structural conclusions are drawn for the reaction products based upon analysis, electrical conductance, magnetic moment and spectral (UV-visible, IR, 1H NMR and 13C NMR) data. FAB mass spectra of these compounds were also recorded to confirm the binuclear structures. Studies were conducted to assess the growth inhibiting potential of the ligands and complexes against various fungal, viral and bacterial strains. Copyright © 2008 John Wiley & Sons, Ltd. [source] | |||||||||||||