581 research outputs found
Radu Marculescu, Diana Marculescu and Massoud Pedram
No full textPower estimation has become a critical step in the design of today's ICs. Power dissipation is strongly input pattern dependent and, hence, to obtain accurate power values one must simulate the circuit with a large number of vectors that typify the application data. The goal of this paper is to present an effective and robust technique for compacting large sequences of input vectors into much smaller ones such that the power estimates are as accurate as possible and the simulation time is reduced by orders of magnitude. Specifically, this paper introduces the hierarchical modeling of Markov chains as a flexible framework for capturing not only complex spatiotemporal correlations, but also the dynamic changes in the sequence characteristics such as different operating modes or power distributions. The new framework is very effective and has a high degree of adaptability: the hierarchical model is dynamically grown according to the sequence behavior and after that is used to generate a new, shorter sequence. As the experimental results show, large compaction ratios can be obtained without significant loss in accuracy (less than 5% on average) for power estimates
System-level power/performance analysis of portable multimedia systems communicating over wireless channels
No full textProlinamide-Supported Polystyrene: a Novel Highly Recyclable Organocatalyst for the Asymmetric Aldol Reaction
No full textNovel prolinamide-supported polystyrene as highly stereoselective and recyclable organocatalyst for the aldol reaction
No full textA new prolinamide derivative anchored to a polystyrene support has been straightforwardly prepared and employed as heterogeneous catalyst in the direct asymmetric aldol reaction with good results in terms of yield and stereoselectivity. The optimal reaction conditions were found when a 1:2 (v/v) water/chloroform mixture was used. This mixture was the best compromise between the good swelling properties of chloroform and the formation of a concentrated organic phase due to the presence of water. Noticeably, the enantioselectivities obtained employing acetone as ketone were, to the best of our knowledge, the highest achieved with a supported proline derivative. This catalyst can be easily recovered, regenerated and recycled, without loss of activity, at least for twelve cycles
Renewable energy from poultry industry using thermo–chemical process strategies for in-situ power generation
No full textThis work analyses comparatively the conversion of poultry litter waste into electric energy considering different thermochemical processes under partial or complete oxidation conditions. By comparing three thermochemical conversion chains in terms of poultry litter waste combustion, pyro-combustion and pyro-gasification, the study main results can be summed up: by varying the typical moisture content from 5 up to 25%, direct combustion of the poultry litter waste represents the best energy recovery solution with a maxim power output of 2.9 MW at 86 t/day feed-flow rate for the considered case. Regarding the pyrolysis by-products (gas, tar, and char) and their chain conversion under fully or reduced atmosphere we can conclude that moisture underlines the treatment choice. In other words, if moisture is higher than 17% poultry litter pyro-gasification is preferable and when is less or equal to 15% poultry litter pyro-combustion is the most suitable option
Solid-state NMR characterization of the structure and thermal stability of hybrid organic-inorganic compounds based on a HLaNb2O7 Dion-Jacobson layered perovskite
No full textDion-Jacobson phases, like MLaNb2O7, are an interesting class of ion-exchangeable layered perovskites possessing electronic and photocatalytic properties. Their protonated and organo-modified homologues, in particular, have already been indicated as promising catalysts. However, the structural analysis of these highly tailorable materials is still incomplete, and both the intercalation process and thermal stability of the included organic moieties are far from being completely understood. In this study, we present a thorough solid-state NMR characterization of HLaNb2O7·xH2O intercalated with different amounts of octylamine, or with decylamine. Samples were analyzed as prepared, and after thermal treatment at different temperatures up to 220 °C. The substitution of pristine proton ions was followed via1H MAS NMR spectroscopy, whereas the alkyl chains were monitored through 13C(1H) CP MAS experiments. The interactions in the interlayer space were explored using 13C(1H) 2D heteronuclear correlation experiments. We demonstrate that some of the protons are involved in the functionalization reaction, and some of them are in close proximity to the alkyl ammonium chains. Heating of the hybrid materials leads first to a rearrangement of the alkyl chains and then to their degradation. The spatial arrangement of the chains, their interactions and the thermal behavior of the materials depend on the extent of the functionalization, and on the nature of the intercalated alkyl ammonium ions
Entretien avec Smaranda Marculescu, Ingénieure d'études au laboratoire IHRIM (Ens de Lyon) et membre de l'équipe HospitAm
No full textNotre collègue Smaranda Marculescu, helléniste spécialiste du judaïsme hellénistique et des cultures juives et chrétiennes antiques et membre fondatrice du projet HospitAm, a été interrogée par le GIS Religions. Pratiques, textes, pouvoirs sur ses recherches consacrées à "La tradition dans le judaïsme hellénistique : entre identité juive et culture grecque". Dans l'entretien vidéo issu de cette rencontre, elle nous parle, entre bien d'autres sujets passionnants, d'accueil et de banquet dans l..
Polystyrene-supported proline and prolinamide. Versatile heterogeneous organocatalysts both for asymmetric aldol reaction in water and alfa-selenenylation of aldehydes
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