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Rev. Sci. Instrum. 50, 1002 (1979] were used with either Re or spring-steel gaskets to compress the samples, which consisted of cryogenically loaded Xe along with Fe powder (<20 |xm grain size) and less than 10 volume % fine-grained ruby (<5 |xm grain size); the latter is used for pressure calibration [H. K. Mao, P. M. Bell, J. W. Shaner, J. Steinberg, J. Appl. Phys. 49, 3276 (1978)]. Samples were heated inside the diamond cell by means of a Quantronix 117 continuous-wave Nd:YAG laser operated in the TEM00 mode, with average temperatures ranging from 1860 (±180) to 3080 (±300) K being documented by imaging spectroradiometry [R. Jeanloz and A. Kavner, Philos. Trans. R. Soc. London Ser. A 354, 1279(1996]. 20. Diffraction patterns were obtained at high pressures and room temperature (before and after laser heating) using a Rigaku 12 kW/mm 2 rotating anode source of monochromatized Mo Ka x-rays. The diffraction patterns were collected in angular-dispersive mode with film and analyzed by methods described elsewhere [J. H. Nguyen and R. Jeanloz, Rev. Sci. Instrum. 64, 3456 (1993)].Epoxides are versatile building blocks for organic synthesis. However, terminal epoxides are arguably the most important subclass of these compounds, and no general and practical method exists for their production in enantiomerically pure form. Terminal epoxides are available very inexpensively as racemic mixtures, and kinetic resolution is an attractive strategy forthe production of optically active epoxides, given an economical and operationally simple method. Readily accessible synthetic catalysts (chiral cobaltbased salen complexes) have been used for the efficient asymmetric hydrolysis of terminal epoxides. This process uses water as the only reagent, no added'solvent, and low loadings of a recyclable catalyst (<0.5 mole percent), and it affords highly valuable terminal epoxides and 1,2-diols in high yield with high enantiomeric enrichment.Asymmetric catalysis provides access t o addition to carbonyl compounds (2). Both optically active epoxides either by oxygen-strategies have been developed t o varying atom transfer to alkenes ( J ) or by carbene degrees, but significant gaps still exist in the scope of these methodologies. For example,

The research presented here was conducted within the scope of an experiment investigating technical feasibility and environmental impacts of tire combustion in a coal-fired power station. Previous work has shown that combustion of a coal+tire blend rather than pure coal increased bulk emissions of various elements (e.g., Zn, As, Sb, Pb). The aim of this study is to characterize the chemical and structural properties of emitted single particles with dimensions <2.5 microm (PM2.5). This transmission electron microscope (TEM)-based study revealed that, in addition to phases typical of coal fly ash (e.g., aluminum-silicate glass, mullite), the emitted PM2.5 contains amorphous selenium particles and three types of crystalline metal sulfates never reported before from stack emissions. Anglesite, PbSO4, is ubiquitous in the PM2.5 derived from both fuels and contains nearly all Pb present in the PM. Gunningite, ZnSO4-H2O, is the main host for Zn and only occurs in the PM derived from the coal+tire blend, whereas yavapaiite, KFe3+(SO4)2, is present only when pure coal was combusted. We conclude that these metal sulfates precipitated from the flue gas, may be globally abundant aerosols, and have, through hydration or dissolution, a major environmental and health impact.

Lanthanum zirconate has been prepared via a new chemical synthesis method by combining sol-gel processing and complex precipitation. The synthesis was carried out in aqueous solution under ambient conditions. The synthesized powder possessed the pyrochlore superstructure upon calcination above 1200°C. A suite of characterization techniques, including FTIR, Raman, X-ray and electron diffraction, TEM, SEM, and nitrogen sorption were employed to investigate the microstructural evolution and bulk properties. Dense ceramics (>90% relative density) were obtained after sintering at 1400°C, without need for additional processing (i.e., hot or cold isostatic pressing) or any milling steps. A mechanism has been proposed that elucidates molecular assembly of this chemical synthesis method.