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Fractional Order (fractional + order)
Selected AbstractsEstimating the Fractional Order of Integration of Yields in the Brazilian Fixed Income MarketECONOMIC NOTES, Issue 3 2007Benjamin M. Tabak This paper presents evidence that yields on the Brazilian fixed income market are fractionally integrated, and compares the period before and after the implementation of the Inflation Targeting (IT) regime. The paper employs the commonly used GPH estimator and recently developed wavelets-based estimator of long memory. Empirical results suggest that interest rates are fractionally integrated and that interest rate spreads are fractionally integrated, with a higher order of integration in the period after the implementation of the IT regime. These results have important implications for the development of macroeconomic models for the Brazilian economy and for long-term forecasting. Furthermore, they imply that shocks to interest rates are long-lived. [source] Uncatalyzed and ruthenium(III)-catalyzed reaction of acidic chlorite with methylene violetINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 7 2003S. B. Jonnalagadda The kinetics and mechanism of the uncatalyzed and Ru(III)-catalyzed oxidation of methylene violet (3-amino-7-diethylamino-5-phenyl phenazinium chloride) (MV+) by acidic chlorite is reported. With excess concentrations of other reactants, both uncatalyzed and catalyzed reactions had pseudo-first-order kinetics with respect to MV+. The uncatalyzed reaction had first-order dependence on chlorite and H+ concentrations, but the catalyzed reaction had first-order dependence on both chlorite and catalyst, and a fractional order with respect to [H+]. The rate coefficient of the uncatalyzed reaction is (5.72 ± 0.19) M,2 s,1, while the catalytic constant for the catalyzed reaction is (22.4 ± 0.3) × 103 M,1 s,1. The basic stoichiometric equation is as follows: 2MV+ + 7ClO2, + 2H+ = 2P + CH3COOH + 4ClO2 + 3Cl,, where P+ = 3-amino-7-ethylamino-5-phenyl phenazinium-10-N-oxide. Stoichiometry is dependent on the initial concentration of chlorite present. Consistent with the experimental results, pertinent mechanisms are proposed. The proposed 15-step mechanism is simulated using literature; experimental and estimated rate coefficients and the simulated plots agreed well with the experimental curves. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 294,303, 2003 [source] A Mechanistic Study on Alcohol Oxidations with Oxygen Catalysed by TPAP-Doped Ormosils in Supercritical Carbon DioxideADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2005Sandro Campestrini Abstract The heterogeneous oxidation of various alcohols with oxygen catalysed by TPAP-doped ormosils in scCO2 at 75,°C and 22.0,MPa has been studied in detail. Sol-gel segregation of TPAP into the inner porosity of an organically modified silica (ormosil) xerogel along with the use of a reaction medium which does not dissolve the catalyst, prevents aggregation of oxidation-inactive ruthenium derivatives without the need of chemical tethering. Thus, at least 140 TONs may be obtained in the oxidation of primary alcohols with the formation of aldehydes as sole reaction products. Investigation of the oxidation mechanism shows that the catalytic process exhibits a first-order dependence on the amount of catalyst, a fractional order on the alcohol concentration and a negative order for oxygen pressures higher than 0.2,bar. Evidence is presented for an associative oxidation mechanism simultaneously involving TPAP, organic substrate and oxygen. [source] Long-memory forecasting of US monetary indicesJOURNAL OF FORECASTING, Issue 4 2006John Barkoulas Abstract Several studies have tested for long-range dependence in macroeconomic and financial time series but very few have assessed the usefulness of long-memory models as forecast-generating mechanisms. This study tests for fractional differencing in the US monetary indices (simple sum and divisia) and compares the out-of-sample fractional forecasts to benchmark forecasts. The long-memory parameter is estimated using Robinson's Gaussian semi-parametric and multivariate log-periodogram methods. The evidence amply suggests that the monetary series possess a fractional order between one and two. Fractional out-of-sample forecasts are consistently more accurate (with the exception of the M3 series) than benchmark autoregressive forecasts but the forecasting gains are not generally statistically significant. In terms of forecast encompassing, the fractional model encompasses the autoregressive model for the divisia series but neither model encompasses the other for the simple sum series.,,Copyright © 2006 John Wiley & Sons, Ltd. [source] Kinetics of oxidation of acidic amino acids and their monoamides by N -chloroarylsulphonamides in aqueous acidic mediumJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 10 2004B. Thimme Gowda Abstract Twelve sodium salts of N -chloroarylsulphonamides were employed as oxidants for studying the kinetics of oxidation of two acidic amino acids (aspartic and glutamic acid) and their monoamides (aspargine and glutamine) in aqueous acidic medium under various conditions, to see how the oxidative strength of these reagents vary with substitution. The sodium salts of N -chloroarylsulphonamides employed are of the general formulae i -X-C6H4SO2NaNCl·xH2O (where i -X,=,4-C2H5, 4-F, 4-Cl or 4-Br) and i -X- j -Y-C6H3SO2NaNCl·xH2O [where i -X- j -Y,=,2,3-(CH3)2, 2,4-(CH3)2, 2,5-(CH3)2, 2-CH3 -4-Cl, 2,4-Cl2 and 3,4-Cl2]. The reactions show second-order kinetics in [oxidant], fractional order in [amino acid] and an inverse dependence on [H+]. Addition of the reduced product of the oxidants or variation in ionic strength of the medium has no significant effect on the rates of oxidations. Mechanisms in conformity with the observed kinetics are discussed. The effective oxidizing species of the oxidants is Cl+ in different forms. The oxidizing strengths of N -chloroarylsulphonamides depend on the ease with which Cl+ is released from them. The study reveals that the introduction of electron-withdrawing groups such as halides to the benzene ring eases the release of Cl+ from the reagent and hence increases the oxidizing strengths of the N -chloroarylsulphonamides. The effect of substituents on Ea of the reactions was analysed by optimising Ea with reference to log,A, and log,A with reference to Ea of the parent oxidant. Copyright © 2004 John Wiley & Sons, Ltd. [source] Mechanistic studies of the oxidation of substituted phenethyl alcohols by N -metallo- N -haloarylsulphonamides: kinetic isotope studiesJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 10 2001Kanchugarakoppal S. Rangappa Abstract The oxidation of para -substituted phenethyl alcohols (PEA, 2) by N -metallo- N -haloarylsulphonamides (1) in the presence of dilute HCl to the corresponding phenacetaldehydes (4) is first order with respect to oxidant (1) and [H+] and a fractional order each in [PEA] and [Cl,]. Addition of the reaction product (3), ionic strength variations and variation of dielectric constant of the medium had no effect on the rate. The oxidation of PhCH2CD2OH (2) exhibited a substantial primary kinetic isotope effect (kH/kD,=,5.83). The rates correlate satisfactorily with the Hammett free energy relationship. The activation parameters ,H,, ,S,, ,G, and logA were calculated for the reaction. The proposed mechanism is consistent with the observed results. Copyright © 2001 John Wiley & Sons, Ltd. [source] Kinetics and Mechanism of Oxidation of Ethylene Glycol Monoethylether by Diperiodatonickelate(IV) in Alkaline MediumCHINESE JOURNAL OF CHEMISTRY, Issue 11 2003Jin-Huan Shan Abstract The kinetics of oxidation of ethylene glycol monoethylether (EGE) by diperiodatonickelate(IV) ion (DPN) was studied by spectrophotometry in alkaline medium. The reaction rate showed first order dependence on Ni(IV) and positive fractional order with respect to EGE. The pseudo-first order rate constants, kobs increased with the increase of [OH,] and decreased with the increase of [IO4,]. Added salts had little effect on the rate and no free radical was detected. Based on these, the mechanism including the equilibrium between DPN and EGE was proposed. Furthermore, the activation parameters of the reaction were calculated. [source] | |||||||||||||