and yttrium have been extracted from an aqueous perchlorate phase a t different acidities into a solution of di-(2-ethylhexyl) hydrogen phosphate in toluene. Separation factors for all the elements of the lanthanide series have been calculated, and the average value for nearest nejghbours was found to be 2.40 f 0.87. The extraction behaviour of yttrium was found to be between those of holmium and erbium.

Barrier systems around the world are experiencing accelerated sea-level rise, reduced sediment supply, and frequent hurricane impacts. However, detailed quantitative field-based studies concerning the response to these external forcing mechanisms are scarce, particularly on the scale of entire islands. The Mississippi-Alabama barrier island chain, located along the U.S. Gulf of Mexico coastline has lost land on the order of hectares per year since records began in the 1840s, putting mainland coastal communities and important ecosystems at risk. Here we present an analysis of Light Detection and Ranging (LiDAR) digital elevation models, revealing erosional/ depositional patterns and geomorphologic changes around the most vulnerable of these islands, Ship Island. Four LiDAR datasets (2004, 2007, 2010, and 2012), capturing the complete topography of the island and some bathymetry in the inlet and surrounding shallows to depths of up to 8 m, are used to investigate subaerial and subaqueous sediment volume changes between these years. The impact of Hurricane Katrina, which produced the highest storm surge ever recorded in the United States, is captured in the 2004-2007 dataset. During this time, sediment comparable to 1.5 times the 2004 subaerial island volume was lost from the area included in the topographic/bathymetric dataset. Only 1/5 of this volume was recovered to this area between 2007 and 2010. The island returned to a state of sediment loss between 2010 and 2012, albeit within the error bounds, while the areal extent of the islands continued to increase. This study examines the impact severe storm events can have on vulnerable barrier islands. It highlights the importance of utilizing 3D datasets that include both topographic and bathymetric data for morphodynamic analyses of barrier island systems.

It is shown that viscosities in the range of 0.2-190 CP can be determined on 6O-pl samples, in an analysis time of about 1 min with reasonable accuracy and a precision of 0.2-0.30/;. The method is basecl on timing a sample injected into a flowing carrier stream over a fixed distance. The factors affecting the dispersion of the sample within the carrier stream have been critically investigated. It is shown that chemical interactions, especially hydrogen bonding, between the sample slug and the carrier stream can crucially affect the dispersion pattern, so that correct choice of carrier is essential for the success of the method. I t can also be used for the determination of molecular diffusion coefficients and it is possible that it could be adapted to cover a wider range of viscosities.The implications of the study to flow injection analysis are discussed. Keywords Viscosity; viscometer ; diffusion coeficient ; computer-controlled analytical instrumentation ; flow injection analysis * For Part I of this series, see Analyst, 1983, 108, 1. ' * (3) At = k6 A7 , . .. where It may also be shown that4 January, 1983 HIGH-PRECISION HIGH-PRECISION FLOW INJECTION ANALYSIS. PART 11 23 * Recently we have read the manuscript of a paper by Gerhardt and Adams (Anal. Chern., December 1982,in the press). They report the use of FIA for the measurement of diffusion coefficients, based on the equations of Vanderslice et. aZ.,12 and draw the conclusion that the method is accurate and potentially more useful than existing methods for the measurement of diffusion coefficients.

No abstract

A procedure to determine total oil content of pecan was developed for samples weighing 500 and 10 mg by supercritica[ fluid extraction (SFE) with carbon dioxide as the extraction solvent, and chilled hexane as the trapping solvent. Fatty acid methyl esters (FAMEs) were prepared from the total lipid fraction by using either an aliquot (500 mg starting weight) or the entire extract (10 mg starting weight). Total oil content obtained for either sample size with SFE was similar to that obtained with an organic solvent extraction technique. The fatty acid composition for the total lipid fraction of oils extracted with SFE was the same as for oils extracted with organic solvents, and oil composition did not change during SFE. Both oil yield and fatty acid composition were similar to those reported previously for pecan. Samples could be extracted and placed into FAMEderivatizing reagents in one day, and fatty acid composition of the total lipid fraction could be determined by gas-liquid chromatography the next day. The procedure, as demonstrated for pecan, should be suitable for other oilseeds, especially those containing low amounts of water. JAOCS 72, 665-669 (1995).KEY WORDS: Fatty acid methyl ester, oilseed, pecan, supercritical fluid extraction.