• Energy Research
• FR close

Abstract. The impact of multiphase reactions involving nitrogen dioxide (NO2) and aromatic compounds was simulated in this study. A mechanism (CAPRAM 2.4, MODAC Mechanism) was applied for the aqueous phase reactions, whereas RACM was applied for the gas phase chemistry. Liquid droplets were considered as monodispersed with a mean radius of 0.1 µm and a liquid content (LC) of 50 µg m-3. The multiphase mechanism has been further extended to the chemistry of aromatics, i.e. reactions involving benzene, toluene, xylene, phenol and cresol have been added. In addition, reaction of NO2 with dissociated hydroxyl substituted aromatic compounds has also been implemented. These reactions proceed through charge exchange leading to nitrite ions and therefore to nitrous acid formation. The strength of this source was explored under urban polluted conditions. It was shown that it may increase gas phase HONO levels under some conditions and that the extent of this effect is strongly pH dependent. Especially under moderate acidic conditions (i.e. pH above 4) this source may represent more than 75% of the total HONO/NO2 - production rate, but this contribution drops down close to zero in acidic droplets (as those often encountered in urban environments).

AbstractHydrodynamics plays a major role in wet grinding processes used to produce nanoparticles, but its influence on the mechanisms of fragmentation is not fully understood. The focus is on hydrodynamics in the gap between two grinding beads. Using particle image velocimetry in a large‐scale experiment, the velocity field between the beads has been investigated when the beads get closer (down to one‐tenth of their radius). Different configurations have been studied, varying from frontal approach to tangential collision. Finally, a capture probability of suspended particles has been estimated.

Abstract Motivation: The steady growth of the number of available protein structures has constantly motivated the development of new algorithms for detecting structural correspondences in proteins. Detecting structural equivalences in two or more proteins is computationally demanding as it typically entails the exploration of the combinatorial space of all possible amino acid pairings in the parent proteins. The search is often aided by the introduction of various constraints such as considering protein fragments, rather than single amino acids, and/or seeking only sequential correspondences in the given proteins. An additional challenge is represented by the difficulty of associating to a given alignment, a reliable a priori measure of its statistical significance. Results: Here, we present and discuss MISTRAL (Multiple STRuctural ALignment), a novel strategy for multiple protein alignment based on the minimization of an energy function over the low-dimensional space of the relative rotations and translations of the molecules. The energy minimization avoids combinatorial searches and returns pairwise alignment scores for which a reliable a priori statistical significance can be given. Availability: MISTRAL is freely available for academic users as a standalone program and as a web service at http://ipht.cea.fr/protein.php. Contact: michelet@sissa.it Supplementary information: Supplementary data are available at Bioinformatics online.

The paper presents a morphodynamic model which can be coupled with any wave model capable of producing time/spectral averaged wave quantities. This model based on a wave energy minimization principle highlights the morphodynamic phenomenology, such as the sandbar creation. Such a model can be used in solving engineering optimization problems. It is also developed to illustrate the idea that beach sand transport can be thought as a non-local phenomenon. We used wave calculations from SWAN and XBeach in our model, and we compared the morphodynamic results to LIP and SANDS hydro-morphodynamic benchmark as well as open-sea simulations. Using supplementary mathematical development, we improved the minimization method using the Hadamard derivative.

Abstract The concept of a cTES (for cold Thermal Energy Storage) is experimentally investigated in this paper. It aims at demonstrating its technical relevancy, for arid regions, in improving the efficiency of a dry cooled turbine's condenser. Gain is realized by postponing total or part of the daily heat exhausted from the condenser and shifting the release of the remaining heat during the night-time when the ambient temperatures are lower. The global system consists in a 13 m3 dual-media water/rock thermocline TES connected to a 110 kW heat source and a 100 kW dry cooler. Experiments have been first conducted to validate the thermal storage behavior in well-controlled operations. Then, the thermal storage has been connected in parallel with the dry cooler to highlight the global behavior of the “dry cooler / cTES” cooling system under different operation's conditions. Results confirm that the cTES is able to compensate the performances loss of the dry cooler during daytime in case of high ambient temperature and to evacuate heat and to store cold during nigh-time. The control of the cTES is simple, characterized by continuous and smooth transitions from one mode to another and without discontinuities in performances and operations.

This dissertation presents a stock-flow consistent (SFC) model which provides a theory-consistent representation of Viet Nam's general structure - a small open economy - and offers policy simulation capabilities to meet the needs of policymakers. We are the first to develop an empirical SFC model for Viet Nam. The model comprises six institutional sectors: firms, central bank, commercial banks, government, households and rest of the world. Due to the availability of financial data, the balance sheet and flow matrix are built based on the principles of the system of national accounting SNA 2008 and by gathering data from different sources. It justifies several simplification hypotheses made in the model. Building upon economic theory but also a data-driven approach, besides accounting equations, behavioural equations are estimated econometrically by using annual data from 1997 to 2019. The model can be used for policy simulation or scenario analysis to assess the impacts/effects of policies or shocks on the Vietnamese economy. We implement three types of shock to test the usefulness of the model: fiscal policy, monetary policy and foreign shock. Then, we analyse the different transmission mechanisms of the effects on economic growth and different components of Gross Domestic Product (GDP), prices and the financial side of the economy, including interest rates and changes in financial assets of each sector. Especially we perform two specific exercises using the model. The first one aims to analyse the different consequences of the policy responses of the Vietnamese government to cope with the COVID-19 pandemic on both the real and financial sides of the economy. We examine the potential effects on public debt sustainability, which is always a concern of the government. The second application is related to the macroeconomic impacts of climate change and the potential effects of adaptation measures by integrating damage functions and adaptation investment into the macroeconomic model. Albeit time-consuming, the ...

Synthesis of cork-derived ceria ecoceramic, an emerging porous catalyst, for enhancing solar thermochemical water splitting.