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Clean combustion technologies, based on reactant dilution, have shown very peculiar and innovative characteristics. Reduction of light and noise emission and uniformity of temperature and composition distribution inside the combustion chamber, related to an extension of the reaction zone, make these processes very promising in several technological fields. Analysis of combustion in very diluted conditions is needed for a general understanding of these processes, which remain unknown from many aspects. The study is also useful for the identification of practical constraints which define the most suitable reactor configurations and working parameters for process reliability. The present work deals with a theoretical analysis of methane oxidation in diluted conditions using one of the detailed kinetic schemes available in the literature. A well-stirred reactor (WSR) configuration has been considered as a first attempt of process schematization. This choice is consistent with the experimental characterization of the flameless combustion processes. The influence of residence time, C/O ratio, and inlet temperature on the steady state was studied for an oxygen molar fraction (0.05), chosen as representative of flameless combustion processes. It has been pointed out that only rich conditions (C/O ? 0.25) are possible for WSR creation, because they allow partial methane conversion. Three kinetic regimes, related to different temperature ranges, have been identified on the basis of product distribution analysis. Both the oxidation and pyrolitic regimes, occurring respectively in low- and high-temperature ranges, are the most interesting working conditions for diluted combustion. The former, leading to CO and H2O as main reaction products, is suitable for reburning technology. The latter, which corresponds to large production of CO and H2, has been shown to be a reasonable explanation of flameless combustion. Advantages and potentials of this innovative process are analyzed, taking into account the kinetic pathway followed in the different working conditions.

With the concept of climate services rapidly climbing research and research-funding agendas worldwide, the time is ripe for a debate about the objectives, scope and content of such services.

The need for European concertation in the area of open archives will continue beyond the term of this project, whether through the continuation of the Open Archives Forum, or by some other means. This report documents a set of sustainability recommendations that have been planned by the project members and discussed with the OAI in US.

The transition to a low carbon future is starting to affect landscapes around the world. In order for this landscape transformation to be sustainable, renewable energy technologies should not cause critical trade-offs between the provision of energy and that of other ecosystem services such as food production. This literature review advances the body of knowledge on sustainable energy transition with special focus on ecosystem services-based approaches and methods. Two key issues emerge from this review: only one sixth of the published applications on the relation between renewable energy and landscape make use of the ecosystem service framework. Secondly, the applications that do address ecosystem services for landscape planning and design lack efficient methods and spatial reference systems that accommodate both cultural and regulating ecosystem services. Future research efforts should be directed to further advancing the spatial reference systems, the use of participatory mapping and landscape visualizations tools for cultural ecosystem services and the elaboration of landscape design principles.

Since 2007, a range of new modeling approaches and tools have been developed for sustainability impact assessment (SIA), but a lack of universal acceptance of SIA tools in applied policy making is observed. The current article gives an overview of experiences from several European and international projects, critically reviews the selected SIA tools and then discusses a number of reasons for the observed disconnect of the tools with the potential users. Largely based on the experiences of the presented SIA tools focusing land use policy advice, a decision tree is designed, which may facilitate an adequate, region and developmental phase specific selection of tool-box components for the development of SIA tools in future. Elements to ensure end-user participation are also integrated in the decision tree in order to increase the likelihood of the tool in applied land use policy advice. In addition, the Challenges in SIA tool development and use are further discussed.

Internal combustion engines are still the energy conversion units of choice in transport and distributed energy generation. Due to the fuel mix, spark ignition (SI) engines represent a viable solution that features improved fuel flexibility with respect to their compression ignition counterparts. Therefore, manufacturers are continuously trying to increase their performance and reduce emissions through experimental and numerical investigations. A growing trend in engine improvement is the application of simulations on a wider scale in order to contain development costs. Combustion is the most complex part of the working cycle and for SI power units, modeling flame propagation represents an essential feature of predictive numerical investigations. Within this context, the present study was aimed at better understanding the mass transfer between unburned and reacting gas, as well as characteristic reaction time scales within the reaction zone. A OD model with three zones was applied for different engine speed, load, air-fuel ratio and spark timing settings, chosen as representative for mid-road load automotive use. Combined in-cylinder pressure measurements and flame imaging were used for validating the essential concept of fresh charge entrainment and burn-up process. One major conclusion of the work was that there is a definite stratification of chemical species within the burned-reacting gas that can be well captured by the entrainment model. The fact that the calibration coefficients require different values for accurate prediction of the pressure traces during flame propagation, emphasizes the complexity of the combustion process, as well as the limitations of considering flames as laminar even at local scale. The study also identified the scale at which mass transfer takes place as an essential factor for correct turbulent combustion modeling. (C) 2015 Elsevier Ltd. All rights reserved.

Abstract We provide a detailed description of a numerically stable and efficient coupling scheme for steady-state Monte Carlo neutronic calculations with thermal–hydraulic feedback. While we have previously derived and published the stochastic approximation based method for coupling the Monte Carlo criticality and thermal–hydraulic calculations, its possible implementation has not been described in a step-by-step manner. As the simple description of the coupling scheme was repeatedly requested from us, we have decided to make it available via this note.

Abstract The Mediterranean region is one of the most vulnerable regions to climate change. The majority of climate models forecast a rise in temperatures and less rainfall, which have been observed in recent decades. These changes will affect several vegetation properties, especially phenological dynamics and traits, by increasing drought intensity and recurrence. In this climate change context, the present study aims to assess the evolution of vegetation state and its relation with the climate dynamics in the Mediterranean forest region of northeast Tunisia using Land Surface Phenology (LSP) metrics and the vegetation index (NDVI) analysis from 2000 to 2017. To conduct this work, we used precipitation and temperature data from the two closest weather stations and 16-day NDVI composite images from the MODIS satellite source, with 250-m spatial resolution. Three phenological metrics— start of season (SOS), end of season (EOS), and length of season (LOS) — were obtained and compared for different vegetation types. The LSP variation in response to climatic metrics was also analyzed. The results showed that the LSP in our study area changed significantly during the 2000–2017 period, which includes an average 7.8 days delay in the SOS, an average advance in the EOS by 5 days, and LOS shortened by an average 12.8 days. Autumn (Pr_9) and spring (Pr_3 and P3_4) precipitations, as well as maximum temperature (Tx9+10), represent the best climate parameters to explain the changes in LSP. Both the NDVI and SPEI showed a significant high correlation (p

In this study we examine the determination accuracy of both the mean radiant temperature (Tmrt) and the Universal Thermal Climate Index (UTCI) within the scope of numerical weather prediction (NWP), and global (GCM) and regional (RCM) climate model simulations. First, Tmrt is determined and the so-called UTCI-Fiala model is then used for the calculation of UTCI. Taking into account the uncertainties of NWP model (among others the HIgh Resolution Limited Area Model HIRLAM) output (temperature, downwelling short-wave and long-wave radiation) stated in the literature, we simulate and discuss the uncertainties of Tmrt and UTCI at three stations in different climatic regions of Europe. The results show that highest negative (positive) differences to reference cases (under assumed clear-sky conditions) of up to -21°C (9°C) for Tmrt and up to -6°C (3.5°C) for UTCI occur in summer (winter) due to cloudiness. In a second step, the uncertainties of RCM simulations are analyzed: three RCMs, namely ALADIN (Aire Limitée Adaptation dynamique Développement InterNational), RegCM (REGional Climate Model) and REMO (REgional MOdel) are nested into GCMs and used for the prediction of temperature and radiation fluxes in order to estimate Tmrt and UTCI. The inter-comparison of RCM output for the three selected locations shows that biases between 0.0 and ±17.7°C (between 0.0 and ±13.3°C) for Tmrt (UTCI), and RMSE between ±0.5 and ±17.8°C (between ±0.8 and ±13.4°C) for Tmrt (UTCI) may be expected. In general the study shows that uncertainties of UTCI, due to uncertainties arising from calculations of radiation fluxes (based on NWP models) required for the prediction of Tmrt, are well below ±2°C for clear-sky cases. However, significant higher uncertainties in UTCI of up to ±6°C are found, especially when prediction of cloudiness is wrong.