Observations of turbulent velocity dispersions in the HI component of galactic discs show a characteristic floor in galaxies with low star formation rates and within individual galaxies the dispersion profiles decline with radius. We carry out several high resolution adaptive mesh simulations of gaseous discs embedded within dark matter haloes to explore the roles of cooling, star-formation, fe...

This review describes the different steps involved in the determination of arsenic in air, considering the particulate matter (PM) and the gaseous phase. The review focuses on sampling, sample preparation and instrumental analytical techniques for both total arsenic determination and speciation analysis. The origin, concentration and legislation concerning arsenic in ambient air are also consid...

KEY WORDS Lipase B from Candida antarctica – Kinetics – transesterification – competitive inhibition – Ping Pong Bi Bi mechanism ABSTRACT The kinetics of alcoholysis of methylpropionate and n-propanol catalyzed by Candida antarctica lipase B supported onto silanized Chromosorb P was studied in a continuous solid/gas reactor. In this system the solid phase is composed of a packed enzymatic sampl...

Atmospheric aerosols are known to provide an important surface for gas-solid interfaces that can lead to heterogeneous reactions impacting tropospheric chemistry. In this work, α-Fe2O3, TiO2, γ-Al2O3, SiO2 and ZnO, common components of atmospheric aerosols, served as models to investigate the gas-solid interface of nitric acid with aerosols in the presence of simulated solar radiation. Adsorbed...

The kinetics of alcoholysis of methyl propionate and n-propanol catalyzed by Candida antarctica lipase B supported onto silanized Chromosorb P was studied in a continuous solid/gas reactor. In this system the solid phase is composed of a packed enzymatic sample and is percolated by nitrogen as carrier gas, which simultaneously carries substrates to the enzyme while removing reaction products. I...

Ellipsometry is a powerful tool to gain the optical properties of materials though measuring the change of polarization state of the probe light after interaction with the sample. It offers a sensitive, nondestructive and comprehensive way to accurately determine film thickness and optical constants of extensive materials, such as metals, ceramics, glasses, semiconductors, and its compounds and...