An approach to measure parameter sensitivity in watershed hydrological modelling.

Hydrological responses vary spatially and temporally according to watershed characteristics. In this study, the hydrological models that we developed earlier for the Little Miami River (LMR) and Las Vegas Wash (LVW) watersheds in the USA were used for detailed sensitivity analyses. To compare the relative sensitivities of the hydrological parameters of these two models, we used normalized root mean square error (NRMSE).

X-ray absorption near edge structure study of lead sorption on phosphate-treated kaolinite.

Presorbed phosphate significantly increases Pb sorption on the phyllosilicate kaolinite in the pH range from 4to 8. The sorbed Pb-to-P molar ratios over this pH range stray little from the molar ratio found in the mineral pyromorphite, suggesting sorbed phosphate reacts with soluble Pb to form a surface precipitate similar to pyromorphite. X-ray absorption near edge structure (XANES) studies at the Pb L3-edge support this interpretation.

The effect of overliming on the toxicity of dilute acid pretreated lignocellulosics: the role of inorganics, uronic acids and ether-soluble organics.

Although the treatment of dilute acid pretreated lignocellulosics with calcium hydroxide or carbonate (overliming) is known to improve the fermentability of carbohydrate-rich hydrolyzate streams, a firm understanding of the chemistry behind the process is lacking. Quantitative evaluation of inorganics, uronic acids, and non-polar organics indicates that only a portion of the improvement can be ascribed to these materials. Upon overliming the concentrations of inorganics either increase (Ca, Mg), decrease (Fe, P, Zn, K) or remain relatively the same (Al, Na).

Characterization of long-chain carboxylic esters with CH3OBOCH 3 (+) in a small fourier-transform ion cyclotron resonance mass spectrometer.

The usefulness of CH3OBOCH 3 (+) as a chemical ionization reagent was examined by allowing the ion to react with carboxylic esters of various chain lengths in a small Fourier-transform ion cyclotron resonance mass spectrometer equipped with a permanent magnet. CH3OBOCH 3 (+) is a strong electrophile and readily abstracts an oxygen-containing group from the carboxylic esters. Long-chain esters exclusively lose the alkoxide moiety to give the acylium ion.