Ricerc@Sapienza

Stationary and dynamic heat and mass transfer analyses of building components are an essential part of energy efficient design of new and retrofitted buildings. Generally, a single constant thermal conductivity value is assumed for each material layer in construction components. However, the variability of thermal conductivity may depend on many factors; temperature and moisture content are among the most relevant ones.

The influence of temperature on the production of enrichment biomass and polyhydroxyalkanoates by activated sludge was evaluated within a practical case study. Two laboratory-scale sequencing batch reactors (SBRs) were operated in parallel over 131 days to treat a wastewater from a potato-starch modification facility, and produce surplus activated sludge biomass with PHA accumulation potential. The SBRs were operated similarly but at different temperatures (15 and 25 °C). Temperature did not influence wastewater treatment performance (average 97% COD removal).

We consider the problem of controlling the rate of failures triggered by fatigue processes of Base Stations (BSs) in cellular networks subject to Sleep Modes (SMs). Specifically, the increase of time spent in SM tends to decrease the BS failure rate by following, e.g., the Arrhenius law. However, the transitions between the power states tend to increase the BS failure rate, which can be predicted by the Coffin- Manson model. In this context, the energy savings triggered by SMs would not be economically useful if the BS failure rate were increased too much.