A new route of oxygen isotope exchange in the solid phase: demonstration in CuSO4.5H2O

Temperature-programmed desorption mass spectrometry (TPD-MS) measurements on [(18)O]water-enriched copper sulfate pentahydrate (CuSO(4).5H(2)(18)O) reveal an unambiguous occurrence of efficient oxygen isotope exchange between the water of crystallization and the sulfate in its CuSO(4) solid phase. To the best of our knowledge, the occurrence of such an exchange was never observed in a solid phase. The exchange process was observed during the stepwise dehydration (50-300 degrees C) of the compound. Specifically, the exchange promptly occurs somewhere between 160 and 250 degrees C; however, the exact temperature could not be resolved conclusively. It is shown that only the fifth, sulfate-associated, anionic H(2)O molecule participates in the exchange process and that the exchange seems to occur in a preferable fashion with, at the most, one oxygen atom in SO(4). Such an exchange, occurring below 250 degrees C, questions the common conviction of unfeasible oxygen exchange under geothermic conditions. This new oxygen exchange phenomenon is not exclusive to copper sulfate but is unambiguously observed also in other sulfate- and nitrate-containing minerals.     

Coordination compounds of indium : XXXVI. The direct electrochemical synthesis of neutral and anionic organoindium halides

The electrochemical oxidation of indium metal in cells of the type leads to the formation of RInX₂ compounds; if 2,2′-bipyridine is also present, the products are the adducts RInX₂·bipy (R = CH₃, C₂H₅, C₆H₅, C₆H₅CH₂, C₆F₅; X = Cl, Br, I (not all combinations)). When R′₄NX is present instead of bipy, the products are the salts R′₄N[RInX₃]. The electrochemical oxidation apparently proceeds via the general mechanism discussed previously. Anomalous results with CH₃I or C₂H₅I are discussed in the light of the known solution chemistry of organoindium(III) compounds.     

A decision support tool for Public Rights of Way officers based on the Analytic Hierarchy Process

Local Government Authorities (LGA) in England and Wales have statutory responsibility for the maintenance of Public Rights of Way (PROW), such as pathways and byways open to non-motorised traffic. The departments responsible have to compete for budgets and justify their expenditure in terms of councils’ priorities, such as well-being and environment. A need was identified for a simple decision support tool to provide a consistent and transparent framework for assessing the range of possible social and economic benefits from expenditure on PROW. The tool uses the Analytic Hierarchy Process to elicit weights forming the links from path attributes to users and usage to benefits, with a final stage to combine the benefits according to LGA priorities. It was successfully tested through case studies, where improving signage was generally found to be the most cost effective option, giving moderate benefits at low cost, whereas improving the physical conditions of the surface gave greater benefits at relatively high cost.     

Measurements Of Biogenic Hydrocarbons And Their Atmospheric Degradation In Forests

Abstract

An analytical procedure for the sampling and quantitative determination of biogenic hydrocarbons in the atmosphere is presented. The method is based on the adsorptive preconcentration of the hydrocarbons using Tenax TA/Carbopack B filled sampling tubes followed by thermodesorption of the trapped compounds and gas chromatographic analysis. To avoid losses of the biogenic alkenes as a consequence of their reaction with ozone on the adsorbents during the sampling step, an ozone scrubber is used in front of the adsorption tubes. Diurnal variations of the monoterpene- and ozone-concentrations are determined at different heights in and above a forest stand (coniferous and deciduous trees) in the Vosges (Col du Donon, 760 m a.s.l.) in order to elucidate the importance of terpene-oxidation reactions on the formation of peroxidic products in forest air.