La rappresentazione territoriale dello sviluppo industriale del Salento nel secondo '900

Il saggio ricostruisce la caratterizzazione produttiva dei centri urbani e rurali e la rappresentazione della geografia dell’industria nell’area dell’antica provincia di Terra d’Otranto nel secondo '900. Le fonti utilizzate sono i Censimenti industriali pubblicati dall’Istat a cadenza decennale dal 1951 al 1991. Per risolvere i problemi di comparabilità ascrivibili ai diversi metodi di classificazione con cui sono stati redatti, tali censimenti sono stati sottoposti a un procedimento di riordino secondo criteri di raccordo in parte originali e in parte già sperimentati dall’Istat. Il saggio consente di individuare a livello comunale e provinciale, per il periodo compreso tra il 1951 e il 1991, il numero di addetti e di unità locali (cioè gli impianti in cui si svolgono le attività produttive) per ogni ramo e classe di attività industriale, la mappa della specializzazione industriale (o attività industriale prevalente) e del tasso d’industrializzazione (rapporto tra lavoratori e popolazione residente)

Thermodynamic Performance of IGCC with Oxy-Combustion CO2 Capture

This paper discusses the relevant thermodynamic aspects of IGCC plants with CO2 capture, mainly focusing on oxy-combustion techniques. The following plant configurations were considered here, all based on a dry-feed oxygen-blown entrained-flow gasifier with syngas quench (Shell type) and a FB class gas turbine: (i) two reference cases, one without CO2 cap-ture and one with ‘conventional’ pre-combustion capture, (ii) three oxy-combustion cases, the first one with today’s technology and the other two with advanced technology, including CO2/SO2 co-sequestration or, alternatively, Hot Gas Desulfurization. It is concluded that oxy-combustion techniques in IGCC cycles may deserve some attention in the near future, because they have the potential of achieving better thermodynamic and en-vironmental performance, in comparison with more conventional capture concepts: in the best case, 45% net efficiency and near-zero emissions were predicted. However, some tech-nological challenges are an obstacle to their development, especially as far as the re-design of the gas turbine is concerned

CO2 Capture from Natural Gas Combined Cycles

This paper presents a comprehensive analysis of three near-term plant configurations for CO2 capture from natural gas-fired power plants based on combined cycle: (i) amine post-combustion separation, (ii) syngas decarbonization, (iii) oxy-combustion. We address them as ‘near-term’ because they do not involve the development of components requiring unproven technology. All configurations are based on a common set of assumptions, reproducing the performance of a status-of-the-art combined cycle based on ‘FB technology’ gas turbine. The performance prediction shows that the best efficiency is achieved by post-combustion (with a loss of efficiency of 6.4 points), followed by pre-combustion, both showing about 90% carbon capture. Oxy-combustion shows a lower efficiency with lower emissions (98% capture, virtually no CO, UHC and NOX emissions). The post-combustion solution also shows the best economics

Cross-species gene-family fluctuations reveal the dynamics of horizontal transfers.

Prokaryotes vary their protein repertoire mainly through horizontal transfer and gene loss. To elucidate the links between these processes and the cross-species gene-family statistics, we perform a large-scale data analysis of the cross-species variability of gene-family abundance (the number of members of the family found on a given genome). We find that abundance fluctuations are related to the rate of horizontal transfers. This is rationalized by a minimal theoretical model, which predicts this link. The families that are not captured by the model show abundance profiles that are markedly peaked around a mean value, possibly because of specific abundance selection. Based on these results, we define an abundance variability index that captures a family's evolutionary behavior (and thus some of its relevant functional properties) purely based on its cross-species abundance fluctuations. Analysis and model, combined, show a quantitative link between cross-species family abundance statistics and horizontal transfer dynamics, which can be used to analyze genome 'flux'. Groups of families with different values of the abundance variability index correspond to genome sub-parts having different plasticity in terms of the level of horizontal exchange allowed by natural selectio