Questions: The existence of reservoirs from which dominant plants recruit after disturbances is a key factor in ecosystem resilience. With this in mind, we ask the following qestion: where do woody species regenerate from in the semiarid Neotropical Chaco forest? Is land use affecting the floristic composition of biodiversity reservoirs? Are the soil and litter seed banks and the juvenile bank potential sources of resilience of these forests in the face of different land‐use regimes? Location: Chancaní, Northwestern Córdoba, Argentina. Methods: We selected four ecosystem types subjected to increasing long‐term land‐use intensity: primary forest (no land use in the last 50 years), secondary forest (low land‐use intensity), closed species‐rich shrubland (moderate land‐use intensity), and open shrubland (high land‐use intensity). We monitored four sites per ecosystem type where we recorded adults, saplings and seedlings of all woody species. We collected litter and soil samples that were processed in the laboratory for taxonomic identification and germination of seeds. We compared the floristic composition of the soil and litter banks, as well as of the juvenile bank (“biodiversity reservoirs”) with that of established vegetation of the primary forest, considered as the reference ecosystem. We also compared the established vegetation from sites under land use with that of the primary forest. Results: Woody species were scarcely represented in the soil, but very well represented in the litter and the juvenile banks from different ecosystem types. These two reservoirs showed high similarity with the established vegetation of the primary forest. However, as land‐use intensity increased, similarity between the reservoirs and the established vegetation of the primary forest decreased. Conclusion: Litter and juvenile banks, but not the soil bank, are the main reservoirs for the recruitment of new individuals of woody species in the Chaco forest. However, the ability of these reservoirs to act as sources of resilience decreases as land use intensifies.

In the field of energy production, cogeneration systems based on micro gas turbine cyclesappear particularly suitable to reach the goals of improving efficiency and reducing pollutants.Moderate and Intense Low-Oxygen Dilution (MILD) combustion represents a promising technologyto increase efficiency and to further reduce the emissions of those systems. The present work aims atdescribing the behavior of a combustion chamber for a micro gas turbine operating in MILD regime.The performances of the combustion chamber are discussed for two cases: methane and biogascombustion. The combustor performed very well in terms of emissions, especially CO and NOx,for various air inlet temperatures and air-to-fuel ratios, proving the benefits of MILD combustion.The chamber proved to be fuel flexible, since both ignition and stable combustion could be achievedby also burning biogas. Finally, the numerical model used to design the combustor was validatedagainst the experimental data collected. The model performs quite well both for methane and biogas.In particular, for methane the Partially Stirred Reactor (PaSR) combustion model proved to be thebest choice to predict both minor species, such as CO, more accurately and cases with lower reactivitythat were not possible to model using the Eddy Dissipation Concept (EDC). For the biogas, the mostappropriate kinetic mechanism to properly model the behavior of the chamber was selected

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The paper presents recent work in the development of a clean and efficient natural gas combustor for a micro-CHP system based on a gas turbine for the residential sector. The large scale deployment of natural gas micro-CHP systems represents a great opportunity to contribute to a reduction of CO2 emissions by a substantial increase of the efficiency of primary energy source conversion. A micro-CHP system, well designed for a residential application, which means a power of 1kWe output and high efficiency (larger than 20%), may reduce annual household emissions up to factors close to 2.5. The micro-CHP system developed in this work uses a small gas turbine and an inverted Brayton cycle which advantageously allows the use of substantially larger turbomachinery components than a conventional pressurized Brayton cycle. The paper presents a new counterflow recuperator. Its design has been thoroughly studied by advanced 3D CFD to obtain compactness and high efficiency at low cost. A new flameless combustor has been developed in order to reduce to single digits the emissions of pollutants (NOx and CO) and obtain a highly efficient and stable combustion for various gases. The design methodology based on 3D CFD modelling is presented as well as experimental results demonstrating the performance of the recuperated flameless combustor for various operationg conditions.