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Cascade Process (cascade + process)
Selected AbstractsStereoselective Synthesis of Bicyclic Pyrrolidines by a Rhodium-Catalyzed Cascade Process.CHEMINFORM, Issue 17 2005Ming Yan Abstract For Abstract see ChemInform Abstract in Full Text. [source] Is a chaotic multi-fractal approach for rainfall possible?HYDROLOGICAL PROCESSES, Issue 6 2001Bellie Sivakumar Abstract An Erratum has been published for this article in Hydrological Processes 15 (12) 2001, 2381,2382. Applications of the ideas gained from fractal theory to characterize rainfall have been one of the most exciting areas of research in recent times. The studies conducted thus far have nearly unanimously yielded positive evidence regarding the existence of fractal behaviour in rainfall. The studies also revealed the insufficiency of the mono-fractal approaches to characterizing the rainfall process in time and space and, hence, the necessity for multi-fractal approaches. The assumption behind multi-fractal approaches for rainfall is that the variability of the rainfall process could be directly modelled as a stochastic (or random) turbulent cascade process, since such stochastic cascade processes were found to generically yield multi-fractals. However, it has been observed recently that multi-fractal approaches might provide positive evidence of a multi-fractal nature not only in stochastic processes but also in, for example, chaotic processes. The purpose of the present study is to investigate the presence of both chaotic and fractal behaviours in the rainfall process to consider the possibility of using a chaotic multi-fractal approach for rainfall characterization. For this purpose, daily rainfall data observed at the Leaf River basin in Mississippi are studied, and only temporal analysis is carried out. The autocorrelation function, the power spectrum, the empirical probability distribution function, and the statistical moment scaling function are used as indicators to investigate the presence of fractal, whereas the presence of chaos is investigated by employing the correlation dimension method. The results from the fractal identification methods indicate that the rainfall data exhibit multi-fractal behaviour. The correlation dimension method yields a low dimension, suggesting the presence of chaotic behaviour. The existence of both multi-fractal and chaotic behaviours in the rainfall data suggests the possibility of a chaotic multi-fractal approach for rainfall characterization. Copyright © 2001 John Wiley & Sons, Ltd. [source] Synthesis of Benzoxazole and Benzimidazole Derivatives via Ligand-Free Copper(I)-Catalyzed Cross-Coupling Reaction of o -Halophenols or o -Haloanilines with CarbodiimidesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2010Guodong Shen Abstract A novel and efficient synthesis of benzoxazole and benzimidazole derivatives via a ligand-free, copper(I)-catalyzed, one-pot cascade process has been developed. A variety of carbodiimides coupled with o -halophenols or o -haloanilines to give the products in moderate to excellent yields under the mild conditions. [source] Cascade Reactions: Catalytic Synthesis of Functionalized 1,3-Dihydroisobenzofuran and Tetrahydrofuran Derivatives by Sequential Nucleophilic Ring Opening,Heterocyclization, Oxidative Carbonylation of AlkynyloxiranesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009Nicola Della Ca' Abstract Differently substituted alkynyloxiranes were efficiently converted into functionalized 1,3-dihydroisobenzofurans and tetrahydrofuran derivatives in fair to good yields by a new cascade reaction, consisting of a sequential nucleophilic ring opening,heterocyclization,oxidative carbonylation process. Reactions were carried out at 80,100,°C and under a 3:1 mixture of carbon monoxide and air (total pressure=32,42,atm at 25,°C) in methanol or acetonitrile/methanol mixtures in the presence of catalytic amounts of palladium diiodide in conjunction with an excess of potassium iodide. The nucleophilic species beginning the cascade process by regioselective attack to the less hindered carbon of the oxirane ring can be methanol itself or iodide anions. [source] An Efficient Domino Approach for the Synthesis of Multisubstituted Pyrroles via Gold/Silver-Catalyzed Amination/Cycloisomerization of (Z)-2-En-4-yn-1-olsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Yuhua Lu Abstract An efficient and one-pot synthesis of multisubstituted pyrroles with high diversity and in a regioselective manner from the reactions of suitably substituted (Z)-enynols with amines or sulfonamides under mild reaction conditions has been developed. This synthesis was realized via a cascade process in the presence of gold/silver (Au/Ag) or boron trifluoride,etherate/gold/silver (BF3,Et2O/Au/Ag) catalysts, which could catalyze amination and cycloisomerization reactions in the same vessel. [source] Monitoring cascade processes using VSI EWMA control chartsJOURNAL OF CHEMOMETRICS, Issue 9 2009Su-Fen Yang Abstract The paper considers the variables process control scheme for cascade process. We construct variable sampling interval (VSI) EWMA and EWMA control charts to effectively monitor the input variable and the output variable produced by a cascade process. Numerical analysis results demonstrate that the performance of the VSI control charts is much better than the fixed sampling interval (FSI) control charts in detecting small and median shifts. Copyright © 2009 John Wiley & Sons, Ltd. [source] Age-related changes of cornu ammonis 1 pyramidal neurons in gerbil transient ischemiaNEUROPATHOLOGY, Issue 3 2000Chiharu Tamagaki This study reports that postischemic apoptotic cell death of the hippocampal cornu ammonis (CA) 1 neurons is delayed in aged gerbils. Age-related changes in the process of CA1 neuronal death following transient ischemia was studied. Two groups of Mongolian gerbils were used in this study, which compared adult (4-month-old) and aged (24-month-old) animals by hematoxylin,eosin stain, in situ nick-end labeling (TUNEL method) and electron microscopy. In the process of neuronal death, neuronal loss of the aged group was histologically less severe than that of the adult group. TUNEL-positive cells were found on days 3,5 after ischemia in the adult group, while they were still found on day 7 in the aged group. The apoptotic process of the aged group was delayed compared to the adult group. Furthermore, lipofuscin was ultrastructurally observed inside the apoptotic body 5 days after ischemia in CA1 pyramidal neurons of the aged group. It is likely that colocalization of lysosomal enzyme cathepsin D with lipofuscin might be associated with the age-related alteration of lysosomal system in the neurons. Altogether these data suggest that age-related lysosomal changes might affect the apoptotic cascade process in postischernic CA1 neurons. [source] Reactive magnetron sputtering of highly (001)-textured WS2,x films: Influence of Ne+, Ar+ and Xe+ ion bombardment on the film growthPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2006K. Ellmer Abstract Layer-type van der Waals semiconductor WS2,x films were grown by radio frequency reactive magnetron sputtering from a metallic tungsten target onto oxidized silicon substrates. The sputtering atmosphere consisted of 75% hydrogen sulfide and 25% neon, argon or xenon. The substrate voltage and hence the energy of the ions bombarding the growing film, was varied from about 20 V (floating potential) to ,80 V. By in situ energy-dispersive X-ray diffraction the growth of the films was monitored and by elastic recoil detection analysis the film composition was measured. It was found that with xenon in the sputtering atmosphere a substrate voltage of ,20 V is sufficient to suppress the crystalline film growth, while for argon as the sputtering rare gas this occurs only at ,80 V. The disturbed film growth is accompanied by a sulfur loss of the growing WS2,x films down to x = 1.1 for sputtering in Ar + H2S at a substrate potential of ,60 V. The results are tentatively explained by the different momentum transfers to sulfur atoms, which is highest for argon ions. It has also to be taken into account that the low-energy xenon bombardment is a many-body cascade process with a much higher local energy density compared to argon and neon bombardment and leading to a higher defect density and a supression of the crystalline growth. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Is a chaotic multi-fractal approach for rainfall possible?HYDROLOGICAL PROCESSES, Issue 6 2001Bellie Sivakumar Abstract An Erratum has been published for this article in Hydrological Processes 15 (12) 2001, 2381,2382. Applications of the ideas gained from fractal theory to characterize rainfall have been one of the most exciting areas of research in recent times. The studies conducted thus far have nearly unanimously yielded positive evidence regarding the existence of fractal behaviour in rainfall. The studies also revealed the insufficiency of the mono-fractal approaches to characterizing the rainfall process in time and space and, hence, the necessity for multi-fractal approaches. The assumption behind multi-fractal approaches for rainfall is that the variability of the rainfall process could be directly modelled as a stochastic (or random) turbulent cascade process, since such stochastic cascade processes were found to generically yield multi-fractals. However, it has been observed recently that multi-fractal approaches might provide positive evidence of a multi-fractal nature not only in stochastic processes but also in, for example, chaotic processes. The purpose of the present study is to investigate the presence of both chaotic and fractal behaviours in the rainfall process to consider the possibility of using a chaotic multi-fractal approach for rainfall characterization. For this purpose, daily rainfall data observed at the Leaf River basin in Mississippi are studied, and only temporal analysis is carried out. The autocorrelation function, the power spectrum, the empirical probability distribution function, and the statistical moment scaling function are used as indicators to investigate the presence of fractal, whereas the presence of chaos is investigated by employing the correlation dimension method. The results from the fractal identification methods indicate that the rainfall data exhibit multi-fractal behaviour. The correlation dimension method yields a low dimension, suggesting the presence of chaotic behaviour. The existence of both multi-fractal and chaotic behaviours in the rainfall data suggests the possibility of a chaotic multi-fractal approach for rainfall characterization. Copyright © 2001 John Wiley & Sons, Ltd. [source] Monitoring cascade processes using VSI EWMA control chartsJOURNAL OF CHEMOMETRICS, Issue 9 2009Su-Fen Yang Abstract The paper considers the variables process control scheme for cascade process. We construct variable sampling interval (VSI) EWMA and EWMA control charts to effectively monitor the input variable and the output variable produced by a cascade process. Numerical analysis results demonstrate that the performance of the VSI control charts is much better than the fixed sampling interval (FSI) control charts in detecting small and median shifts. Copyright © 2009 John Wiley & Sons, Ltd. [source] High-energy neutrino emission from low-mass microquasarsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2010J. F. Zhang ABSTRACT In this paper we study the high-energy neutrino emission from low-mass microquasars (LMMQs) by assuming that an acceleration region for particles is located in the inner jet, based on the framework of a hadronic jet model. Adopting the parametrized formulae for inelastic pp interactions and the recent p, parametrizations, we calculate the spectral energy distributions (SEDs) of various photon and neutrino spectra. Furthermore, we also consider the electromagnetic cascade processes due to ,, absorption. We then apply the jet model to the microquasar (MQ) GX 339,4, and calculate the expected neutrino event rate for three years of observations using the newest effective area of the KM3NeT detector in the Mediterranean Sea. The resulting results indicate that (1) photon spectra can roughly reproduce observations from radio to X-ray energies, and can also predict emission fluxes at high and very high energies (VHE); (2) GX 339,4 is a potential neutrino source, neutrinos from which are likely to be identified with some years of observations from the next-generation -scale neutrino telescopes. [source] | |||||||||||||