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Several industrial sectors, such as for example cement manufacturers and lime producers, produce so-called “unavoidable” CO2 emissions because these ones are intrinsically linked to the industrial process itself (decarbonation of calcium carbonate). In order to reduce these emissions, it is necessary to implement a Carbon Capture, Utilization and/or Storage (CCUS) process chain, whose step of capture, although already technologically mature (especially the absorption-regeneration process using amine(s)-based solvents), leads to very high energy consumption. Three pathways to reduce this consumption have been investigated (experimentally and/or through the development of Aspen PlusTM simulations), namely: (i) upstream of the process thanks to the increase of the flue gas CO2 content (by partial oxy-combustion and/or flue gas recirculation), (ii) within the process (using more efficient and innovative mixtures of solvents such as demixing solutions), and (iii) at the configurational level by using advanced configurations in the capture process. It emerged that the use of a demixing process such as the mixture composed of diethylethanolamine (DEEA) and methylamino-propylamine (MAPA), or the implementation of an advanced process configuration (InterCooling Absorber + Rich Vapor Compression + Rich Solvent Splitting and Preheating, with methyldiethanolamine (MDEA) + piperazine (PZ) as a solvent) are the most energy reducing pathways for the absorption-regeneration process, i.e. more than 40% in comparison with a conventional process using monoethanolamine (MEA). Moreover, from an economical point of view, and compared to a basic configuration with MEA, the demixing technology has the advantage of being able to achieve such energy performance with a more limited investment (CAPEX) (+1.6%) than with advanced process configurations (+8.8%).

Using Si as anode materials for Li-ion batteries remain challenging due to its morphological evolution and SEI modification upon cycling. The present work aims at developing a composite consisting of carbon-coated Si nanoparticles (Si@C NPs) intimately embedded in a three-dimensional (3D) graphene hydrogel (GHG) architecture to stabilize Si inside LiB electrodes. Instead of simply mixing both components, the novelty of the synthesis procedure lies in the in situ hydrothermal process, which was shown to successfully yield graphene oxide reduction, 3D graphene assembly production, and homogeneous distribution of Si@C NPs in the GHG matrix. Electrochemical characterizations in half-cells, on electrodes not containing additional conductive additive, revealed the importance of the protective C shell to achieve high specific capacity (up to 2200 mAh.g−1), along with good stability (200 cycles with an average Ceff > 99%). These performances are far superior to that of electrodes made with non-C-coated Si NPs or prepared by mixing both components. These observations highlight the synergetic effects of C shell on Si NPs, and of the single-step in situ preparation that enables the yield of a Si@C-GHG hybrid composite with physicochemical, structural, and morphological properties promoting sample conductivity and Li-ion diffusion pathways. [ABSTRACT FROM AUTHOR]

Summary: To limit the increase of the global average temperature in the range of 1.5°C to 2°C above pre‐industrial levels, it is mandatory to reduce anthropogenic CO2 emissions. Aggressive mitigation measures are thus needed to tackle these emissions leading to "net negative CO2 emissions." The present study focuses on direct air capture (DAC) processes among the diverse negative emissions approaches. DAC refers to man‐made technologies that selectively extract CO2 from ambient air and deliver it in a concentrated form for further use or storage. DAC technologies are currently developed at different levels of maturity and performance. They can be classified into three main approaches, the liquid sorbent approach, the solid sorbent approach, and a panel of more innovative technologies combining different approaches. They involve various unit operations and different materials and energy types (electrical and thermal). To better evaluate the status and both the environmental and economic performances, the present paper provides a literature review of the life cycle (LCA) and techno‐economic (TEA) assessments in relation to DAC process chains. It was emphasized that DAC could lead to negative emissions if paired with subsequent storage, while the production of synthetic fuels can at best be carbon neutral when using CO2 from the air. Building large DAC plants has an impact on the amount of energy required to operate them, as well as other environmental impacts with regard to land, water, and material use. Even if the carbon‐negative characteristic of DAC was confirmed, these technologies are still expensive. It was highlighted that large DAC costs ranges are currently provided in the literature, from €80/tCO2 to €1133/tCO2 for the current DAC processes, while estimations from €34 to €260/tCO2 are expected in the future. Different levers were identified to improve the environmental and economic performances of DAC processes, such as the availability of waste heat, the heat integration possibilities, and, among others, the improvement of contactors and sorbents properties. Highlights: The paper entitled "Life cycle and techno‐economic assessments of direct air capture processes: An integrated review," submitted by Dr Remi Chauvy and Dr Lionel Dubois, fills the current gap in terms of comprehensive systematic and impacts assessment research on Direct Air Capture (DAC) technologies.Indeed, to better evaluate the status and both the environmental and economic performances of DAC technologies, the present paper provides an up‐to‐date literature review of the life cycle (LCA) and techno‐economic (TEA) assessments in relation with DAC process chains.The paper goes beyond the literature review as key levers, related to technology developments, to the energy use and to the implementation characteristics, are also identified to improve the environmental and economic performances of DAC processes. [ABSTRACT FROM AUTHOR]

The study of the interaction between xenon and two cryptophane derivatives in organic solution is carried out. The results clearly indicate that in the design of new cage molecules for biosensing, the separation of cryptophane diastereomers is important because their affinity and their properties vis-a-vis could be strongly different.

Longitudinal relaxation times T(sub 1) of laser-polarized xenon in water solutions containing alpha-cylodextrin and wheat nonspecific lipid transfer protein are measured. It reveals that even with an atom of high polarizability, such as xenon, the van der Waals energy is not sufficiently predominant to avoid large amplitude motions of an apolar guest around its average sites.

'Mythology is the collection of myths of a people, a civilization, a religion.' Those myths may vary from the cosmogonic to the historic (from the transfiguration of a feat of [...]

The evolution in the design of modern parallel platforms leads to revisit the scheduling jobs on distributed heterogeneous resources. The goal of this survey is to present the main existing algorithms, to classify them based on their underlying principles, and to propose unified implementations to enable their fair comparison, in terms of running time and quality of schedules, on a large set of common benchmarks that we made available for the community. Beyond this comparison, our goal is also to understand the main difficulties that heterogeneity conveys and the shared principles that guide the design of efficient algorithms. [ABSTRACT FROM AUTHOR]

The problem of partitioning dense matrices into sets of sub-matrices has received increased attention recently and is crucial when considering dense linear algebra and kernels with similar communication patterns on heterogeneous platforms. The problem of load balancing and minimizing communication is traditionally reducible to an optimization problem that involves partitioning a square into rectangles. This problem has been proven to be NP-Complete for an arbitrary number of partitions. In this paper, we present recent approaches that relax the restriction that all partitions be rectangles. The first approach uses an original mathematical technique to find the exact optimal partitioning. Due to the complexity of the technique, it has been developed for a small number of partitions only. However, even at a small scale, the optimal partitions found by this approach are often non-rectangular and sometimes non-intuitive. The second approach is the study of approximate partitioning methods utilizing recursive partitioning algorithms. In particular we use the work on optimal partitioning to improve pre-existing algorithms. In this paper we discuss the different perspectives this approach opens and present two algorithms, SNRPP which is a $\sqrt{\frac{3}{2}}$ approximation, and NRPP which is a $\frac{2}{\sqrt{3}}$ approximation. While sub-optimal, the NRRP approach works for an arbitrary number of partitions. We use the first exact approach to analyse how close to the known optimal solutions the NRRP algorithm is for small numbers of partitions. [ABSTRACT FROM AUTHOR]

We consider the classical problem of broadcasting a large message at an optimal rate in a large scale distributed network under the multi-port communication model. In this context, we are interested in both building an overlay network and providing an explicit algorithm for scheduling the communications. From an optimization point of view, we aim both at maximizing the throughput (i.e., the rate at which nodes receive the message) and minimizing the degree of the participating nodes, i.e., the number of TCP connections they must handle simultaneously. The main novelties of our approach are the introduction of this degree constraint and the classification of the set of participating nodes into two parts: open nodes that stay in the open-Internet and “guarded” nodes that lie behind firewalls or NATs. Two guarded nodes cannot communicate directly, but rather need to use an open node as a gateway for transmitting a message. In the case without guarded nodes, we prove that it is possible to reach the optimal throughput, at the price of a quasi-optimal (up to a small additive increase) degree of the participating nodes. In presence of guarded nodes, our main contributions are a closed form formula for the optimal cyclic throughput and the proof that the optimal solution may require arbitrarily large degrees. In the acyclic case, we propose an algorithm that reaches the optimal throughput with low degree. Then, we prove a worst case ratio between the optimal acyclic and cyclic throughput and show through simulations that this ratio is on average very close to 1, what makes acyclic solutions efficient both in terms of throughput maximization and degree minimization. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of our work was to evaluate separately the absorption and regeneration performances of different types of amine(s) based solvents (primary, secondary and tertiary alkanolamines, sterically hindered amines, non-cyclical tetramine and cyclical absorption activators) by carrying out screening tests using small scale apparatus: a gas-liquid contactor for absorption, namely a double-stirred cell, and a regeneration cell. Absorption and regeneration performances of the solvents were compared thanks to calculated absorption and regeneration efficiencies. Concerning the absorption results, the positive effect of an activator, and especially the cyclical di-amine piperazine (PZ), on the absorption performances of the different simple amine solutions was clearly highlighted. The activation of the secondary amine MMEA by PZ gives also higher absorption efficiencies. Regarding the regeneration tests, the better regeneration performances of tertiary and sterically hindered amines (MDEA and AMP) were confirmed. For the amines blends, higher regeneration performances were observed with PZ activated solutions than with PIP activated solutions. These absorption and regeneration results will be taken into account in the solvent selection for future combined absorption-regeneration tests. [Copyright &y& Elsevier]

Abstract: The purpose of this work was to evaluate the absorption-regeneration performances of different types of amine(s) based solvents (primary, secondary and tertiary alkanolamines, sterically hindered amines, non-cyclical tetramine and cyclical absorption activators), previously selected thanks to a methodological study and separate laboratory absorption and regeneration tests. In this work absorption-regeneration experiments were carried out using a newly developed CO2 capture laboratory micro-pilot and applying a high gaseous CO2 content (from 20% to 30%) representative of cement plant flue gases. The different experiments allowed us to compare a large number of solvents (simples and blends) by weighing absorption and regeneration performances measured in our plant. The positive effect of an activator (especially the cyclical di-amine piperazine, from 5 to 10%) on the absorption-regeneration performances of the different solutions (especially on the sterically hindered amine 2-amino-2-methyl-1-propanol and on the secondary amines diethanolamine and methylmonoethanolamine, 30% solutions) was clearly highlighted. The influence of other components present in industrial emissions, especially in cement plant flue gases (mainly O2, SOx, and NOx), on the absorption-regeneration performances of the amine solvents was also studied. [Copyright &y& Elsevier]

In this paper, we consider the problem of assigning a set of clients with demands to a set of servers with capacities and degree constraints. The goal is to find an allocation such that the number of clients assigned to a server is smaller than the server's degree and their overall demand is smaller than the server's capacity, while maximizing the overall throughput. This problem has several natural applications in the context of independent tasks scheduling or virtual machines allocation. We consider both the offline (when clients are known beforehand) and the online (when clients can join and leave the system at any time) versions of the problem. We first show that the degree constraint on the maximal number of clients that a server can handle is realistic in many contexts. Then, our main contribution is to prove that even if it makes the allocation problem more difficult (NP-Complete), a very small additive resource augmentation on the servers degree is enough to find in polynomial time a solution that achieves at least the optimal throughput. After a set of theoretical results on the complexity of the offline and online versions of the problem, we propose several other greedy heuristics to solve the online problem and we compare the performance (in terms of throughput) and the cost (in terms of disconnections and reconnections) of all proposed algorithms through a set of extensive simulation results. [ABSTRACT FROM AUTHOR]

Molecular hydrophobic cavities can be mapped thanks to the detection of magnetization transfer from laser polarized xenon to nearby protons. This so called SPINOE approach is described. The study of the spin dynamics during this experiment and its consequences on the practical implementation are detailed. We show that thanks to the knowledge of the physical properties of the system, it becomes possible to choose the best experimental conditions in order to be able to assign magnetization transfer through two dimensional NMR methods. As an illustration, the first 2D SPIROE-TOCSY experiment is reported. To cite this article: L. Dubois et al., C. R. Physique 5 (2004). [Copyright &y& Elsevier]

This article focuses on the book "Afro-Antillean Literature in French," by Roger Toumson. The book is published in two volumes and the author's goal is to establish how, why and when Afro-Antillean literature acceded to a meaningful autonomy. The book is divided into three sections. It starts with a discussion of methodology and a definition of its topic. The second section is an attempt to characterize the white "Creole" literary production of the earlier period and it focuses in particular on the rise of an Antillean regionalism. The third section presents an account of the discursive system of Negritude, highlighting factors that helped bring about the birth and subsequent evolution of a literary ideology based upon a cultural and racial coming to awareness.