Polymer Maximum Drag Reduction: A Unique Transitional State

The upper bound of polymer drag reduction is identified as a unique transitional state between laminar and turbulent flow corresponding to the onset of the nonlinear breakdown of flow instabilities

On the role of pressure in elasto-inertial turbulence

The dynamics of elasto-inertial turbulence is investigated numerically from the perspective of the coupling between polymer dynamics and flow structures. In particular, direct numerical simulations of channel flow with Reynolds numbers ranging from 1000 to 6000 are used to study the formation and dynamics of elastic instabilities and their effects on the flow. Based on the splitting of the pressure into inertial and polymeric contributions, it is shown that the polymeric pressure is a non-negligible component of the total pressure fluctuations, although the rapid inertial part dominates. Unlike Newtonian flows, the slow inertial part is almost negligible in elasto-inertial turbulence. Statistics on the different terms of the Reynolds stress transport equation also illustrate the energy transfers between polymers and turbulence and the redistributive role of pressure. Finally, the trains of cylindrical structures around sheets of high polymer extension that are characteristics of elasto-inertial turbulence are shown to be correlated with the polymeric pressure fluctuations

Radiation Modeling of a Hydrogen-Fueled Scramjet

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90696/1/AIAA-2011-3769-521.pd

Detection of new protein domains using co-occurrence: application to Plasmodium falciparum

International audienceMotivation: Hidden Markov Models (HMMs) have proved to be a powerful tool for protein domain identification in newly sequenced organisms. However, numerous domains may be missed in highly divergent proteins. This is the case for Plasmodium falciparum proteins, the main causal agent of human malaria. Results: We propose a method to improve the sensitivity of HMM domain detection by exploiting the tendency of the domains to appear preferentially with a few other favorite domains in a protein. When sequence information alone is not sufficient to warrant the presence of a particular domain, our method enables its detection on the basis of the presence of other Pfam or InterPro domains. Moreover, a shuffling procedure allows us to estimate the false discovery rate associated with the results. Applied to P. falciparum, our method identifies 585 new Pfam domains (versus the 3683 already known domains in the Pfam database) with an estimated error rate below 20%. These new domains provide 387 new Gene Ontology annotations to the P. falciparum proteome. Analogous and congruent results are obtained when applying the method to related Plasmodium species, P. vivax and P. yoelii. Availability: Supplementary Material and a database of the new domains and GO predictions achieved on Plasmodium proteins are available at http://www.lirmm.fr/~terrapon/codd

Full-system RANS of the HyShot II scramjet Part 1: Numerics and non-reactive simulations

Predictive Science Academic Alliance Program (PSAAP

EuPathDomains: The Divergent Domain Database for Eukaryotic Pathogens

International audienceEukaryotic pathogens (e.g. Plasmodium, Leishmania, Trypanosomes, etc.) are a major source of morbidity and mortality worldwide. In Africa, one of the most impacted continents, they cause millions of deaths and constitute an immense economic burden. While the genome sequence of several of these organisms is now available, the biological functions of more than half of their proteins are still unknown. This is a serious issue for bringing to the foreground the expected new therapeutic targets. In this context, the identification of protein domains is a key step to improve the functional annotation of the proteins. However, several domains are missed in eukaryotic pathogens because of the high phylogenetic distance of these organisms from the classical eukaryote models. We recently proposed a method, co-occurrence domain detection (CODD), that improves the sensitivity of Pfam domain detection by exploiting the tendency of domains to appear preferentially with a few other favorite domains in a protein. In this paper, we present EuPathDomains (http://www.atgc-montpellier.fr/EuPathDomains/), an extended database of protein domains belonging to ten major eukaryotic human pathogens. EuPathDomains gathers known and new domains detected by CODD, along with the associated confidence measurements and the GO annotations that can be deduced from the new domains. This database significantly extends the Pfam domain coverage of all selected genomes, by proposing new occurrences of domains as well as new domain families that have never been reported before. For example, with a false discovery rate lower than 20%, EuPathDomains increases the number of detected domains by 13% in Toxoplasma gondii genome and up to 28% in Cryptospordium parvum, and the total number of domain families by 10% in Plasmodium falciparum and up to 16% in C. parvum genome. The database can be queried by protein names, domain identifiers, Pfam or Interpro identifiers, or organisms, and should become a valuable resource to decipher the protein functions of eukaryotic pathogens

Sustainable transformation of energy systems in MENA countries : comparative report

A clear understanding of socio-technical interdependencies and a structured vision are prerequisites for fostering and steering a transition to a fully renewables-based energy system. To facilitate such understanding, a phase model for the renewable energy (RE) transition in the Middle East and North Africa (MENA) countries has been developed and applied to ten countries: Algeria, Egypt, Iraq, Israel, Jordan, Lebanon, Morocco, Palestine, Tunisia, and Yemen. This report synthesises the results of these ten studies. The analysis shows that the state of the energy sector in the MENA region varies from country to country, but some underlying trends are present in all countries. In the majority of countries, energy prices are subsidised, and energy markets are mostly not liberalised. The energy demand in all analysed countries is growing and most grid systems are poorly interconnected across borders. Still, the expansion of RE in the MENA region can benefit from significant global progress and cost reductions in RE technologies. Reducing greenhouse gas (GHG) emissions is not the only key driver for energy transition. In fact, the main motives for transition are that RE can help to meet growing demand, reduce dependence on imports, increase energy security, and provide opportunities for economic development. All countries studied have RE targets. While some countries are on track to meet these targets, others need to increase their efforts to expand renewable electricity generation in order to meet their goals. Strong progress has been made in countries with limited fossil energy resources, while in some countries that produce and export large amounts of fossil energy resources, the energy transition is progressing rather slowly

Sustainable transformation of Tunisia's energy system : development of a phase model

A clear understanding of socio-technical interdependencies and a structured vision are prerequisites for fostering and steering a transition to a fully renewables-based energy system. To facilitate such understanding, a phase model for the renewable energy (RE) transition in the Middle East and North Africa (MENA) countries has been developed and applied to the country case of Tunisia. It is designed to support the strategy development and governance of the energy transition and to serve as a guide for decision makers. The analysis shows that Tunisia has already taken important steps towards a RE transition. According to the MENA phase model, Tunisia can be classified as being in the "Take-Off Renewables" phase. Nevertheless, natural gas still plays the dominant role in Tunisia's highly subsidised electricity generation. In addition to the elevated political uncertainty, there are numerous structural, political, social, and economic challenges within the energy sector that hinder progress in the transition to REs. Strong support at all levels is needed to promote the breakthrough of RE. This includes more detailed long-term planning and improving the regulatory framework, as well as reducing offtaker risks to improve the bankability of RE projects in order to attract private investment. Furthermore, institutional buy-in needs to be increased and the engagement of key non-state stakeholders must be strengthened. In light of the growing domestic energy demand and with the on-going global decarbonisation efforts in favour of sustainable fuels, Tunisia would be well advised to embark on a sustainable energy path sooner rather than later to seize economic opportunities that can arise from RE development