Urban tracer dispersion experiment in London (DAPPLE) 2003: field study and comparison with empirical prediction

The DAPPLE (Dispersion of Air Pollutants and their Penetration into the Local Environment) project seeks to characterise near-field urban atmospheric dispersion using a multidisciplinary approach. In this paper we report on the first tracer dispersion experiment carried out in May 2003. Results of concurrent meteorological measurements are presented. Variations of receptor tracer concentration with time are presented. Meteorological observations suggest that in-street channelling and flow-switching at intersections take place. A comparison between roof top and surface measurements suggest that rapid vertical mixing occurs, and a comparison between a simple dispersion model and maximum concentrations observed are presented

Testing isotherm models and recovering empirical relationships for adsorption in microporous carbons using virtual carbon models and grand canonical Monte Carlo simulations

Using the plausible model of activated carbon proposed by Harris and co-workers and grand canonical Monte Carlo simulations, we study the applicability of standard methods for describing adsorption data on microporous carbons widely used in adsorption science. Two carbon structures are studied, one with a small distribution of micropores in the range up to 1 nm, and the other with micropores covering a wide range of porosity. For both structures, adsorption isotherms of noble gases (from Ne to Xe), carbon tetrachloride and benzene are simulated. The data obtained are considered in terms of Dubinin-Radushkevich plots. Moreover, for benzene and carbon tetrachloride the temperature invariance of the characteristic curve is also studied. We show that using simulated data some empirical relationships obtained from experiment can be successfully recovered. Next we test the applicability of Dubinin's related models including the Dubinin-Izotova, Dubinin-Radushkevich-Stoeckli, and Jaroniec-Choma equations. The results obtained demonstrate the limits and applications of the models studied in the field of carbon porosity characterization.

Are local economic development incentives promoting job growth? An empirical case study

At a time when cities are competing with one another to attract or retain jobs within a globalizing economy, city governments are providing an array of financial incentives to stimulate job growth and retain existing jobs, particularly in high cost locations. This paper provides the first systematic and comprehensive analysis of datasets on economic development incentives in New York City over the last fifteen years. The evidence on job retention and creation is mixed. Although many companies do not meet their agreed-upon job targets in absolute terms, the evidence suggests that companies receiving subsidies outperform their respective industries in terms of employment growth, that is, the grow more, or decline less. We emphasize that this finding is difficult to interpret, since firms receiving incentives may not be representative of the industry as a whole. In other words, their above-average performance may simply reflect the fact that the Economic Development Corporation (EDC) selects economically promising companies within manufacturing (or other industries) when granting incentives. At the same time, it is also possible that receiving incentives helps these companies to become stronger.