Real-time multipurpose reservoir operation: a case study / Exploitation en temps reacuteel d'un reservoir agrave buts multiples: eacutetude d'un cas

A real-time operational methodology has been developed for multipurpose reservoir operation for irrigation and hydropower generation with application to the Bhadra reservoir system in the state of Karnataka, India. The methodology consists of three phases of computer modelling. In the first phase, the optimal release policy for a given initial storage and inflow is determined using a stochastic dynamic programming (SDP) model. Streamflow forecasting using an adaptive AutoRegressive Integrated Moving Average (ARIMA) model constitutes the second phase. A real-time simulation model is developed in the third phase using the forecast inflows of phase 2 and the operating policy of phase 1. A comparison of the optimal monthly real-time operation with the historical operation demonstrates the relevance, applicability and the relative advantage of the proposed methodology.

Kinetics of ceric ion oxidation of naphthalene and its derivatives. Formation of the radical cation intermediate in the rate limiting step

Ceric ammonium sulfate, CAS, oxidizes naphthalene to 1,4-naphthoquinone in essentially quantitative yield in CH3CN-dil. H2SO4. Stoichiometric studies indicate that 6 mol of CAS are required for the oxidation of 1 mol of naphthalene to 1,4-naphthoquinone. Kinetic investigations reveal that the reaction takes place through initial formation of a 1:1 complex of naphthalene and cerium(IV) in an equilibrium step followed by slow decomposition of the complex to naphthalene radical cation. Kinetic results on the effects of acid strength, polarity of the medium, temperature and substituents are in accordance with this mechanism. Further conversion of the radical cation into 1,4-naphthoquinone takes place in fast steps involving a further 5 mol of cerium(IV) and 2 mol of H2O.

High Rydberg state carbon recombination lines toward Cassiopeia A: 332 MHz VLA observations and comparison with H I and molecular lines

We present observations of the C270alpha carbon recombination line, 21 cm neutral hydrogen line and (CO)-C-12 (J = 1 --> 0) molecular line toward Cas A. A comparison of the distribution of recombination line optical depths over the face of Cas A with that of H I optical depths and molecular line emission favors the association of C270alpha regions with H I rather than molecular clouds. The association makes it possible to self-consistently determine several physical parameters of the clouds by combining the recombination line and 21 cm H I measurements.

Carbon recombination lines between 34.5 and 770 MHz toward Cassiopeia A

We present observations of low-frequency recombination lines of carbon toward Cas A near 34.5 MHz (n similar to 575) using the Gauribidanur radio telescope and near 560 MHz (n similar to 225) and 770 MHz (n similar to 205) using the NRAO 140 foot (43 m) telescope in Greenbank. We also present high angular resolution (1') observations of the C270 alpha line near 332 MHz using the Very Large Array in B-configuration. A high signal-to-noise ratio spectrum is obtained at 34.5 MHz, which clearly shows a Voigt profile with distinct Lorentzian wings, resulting from significant pressure and radiation broadening at such high quantum numbers. The emission lines detected near 332, 550, and 770 MHz, on the other hand, are narrow and essentially Doppler-broadened. The measured Lorentzian width at 34.5 MHz constrains the allowed combinations of radiation temperature, electron density, and electron temperature in the line-forming region. Radiation broadening at 34.5 MHz places a lower limit of 115 pc on the separation between Cas A and the line-forming clouds. Modeling the variation in the integrated line-to-continuum ratio with frequency indicates that the region is likely to be associated with the cold atomic hydrogen component of the interstellar medium, and the physical properties of this region are likely to be T-e = 75 K, n(e) = 0.02 cm(-3), T-R100 = 3200 K, and n(H) T-e = 10,000 cm(-3) K. Comparison of the distribution of the C270 alpha recombination line emission across Cas A with that of (CO)-C-12 and H I also supports the above conclusion.

Mixed ionic and electronic conduction in zirconia and its applications in metallurgy

Mixed ionic and electronic conduction in Zr02-based solid electrolytes was studied.The effect of impurities and second-phase particles on the mixed conduction parameter, P,, was measured for different types of ZrOZ electrolytes. The performance of solid-state sensors incorporating ZrOZ electrolytes is sometimes limited by electronic conduction in ZrOZ, especially at temperatures >I800 K. Methods for eliminating or minimizing errors in measured emf due to electronically driven transport of oxygen anions are discussed. Examples include probes for monitoring oxygen content in liquid steel as well as the newly developed sulfur sensor based on a ZrOz(Ca0) + CaS electrolyte. The use of mixed conducting ZrOZ as a semipermeable membrane or chemically selective sieve for oxygen at high temperatures is discussed. Oxygen transport from liquid iron to CO + C& gas mixtures through a ZrOZ membrane driven by a chemical potential gradient, in the absence of electrical leads or imposed potentials, was experimentally observed.