521 research outputs found
The leading non-perturbative coefficient in the weak-coupling expansion of hot QCD pressure
Using Numerical Stochastic Perturbation Theory within three-dimensional pure
SU(3) gauge theory, we estimate the last unknown renormalization constant that
is needed for converting the vacuum energy density of this model from lattice
regularization to the MSbar scheme. Making use of a previous non-perturbative
lattice measurement of the plaquette expectation value in three dimensions,
this allows us to approximate the first non-perturbative coefficient that
appears in the weak-coupling expansion of hot QCD pressure.Comment: 16 pages. v2: published versio
Renormalization of infrared contributions to the QCD pressure
Thanks to dimensional reduction, the infrared contributions to the QCD
pressure can be obtained from two different three-dimensional effective field
theories, called the Electrostatic QCD (Yang-Mills plus adjoint Higgs) and the
Magnetostatic QCD (pure Yang-Mills theory). Lattice measurements have been
carried out within these theories, but a proper interpretation of the results
requires renormalization, and in some cases also improvement, i.e. the removal
of terms of O(a) or O(a^2). We discuss how these computations can be
implemented and carried out up to 4-loop level with the help of Numerical
Stochastic Perturbation Theory.Comment: 7 pages, 4 figures, talk presented at Lattice 2006 (High temperature
and density
New Perspectives on Catalytic Hydrogen Production by the Reforming, Partial Oxidation and Decomposition of Methane and Biogas
The article provides a short review on catalyst-based processes for the production of hydrogen starting from methane, both of fossil origin and from sustainable processes. The three main paths of steam- and dry-reforming, partial oxidation and thermo-catalytic decomposition are briefly introduced and compared, above all with reference to the latest publications available and to new catalysts which obey the criteria of lower environmental impact and minimize the content of critical raw materials. The novel strategies based on chemical looping with CO2 utilization, membrane separation, electrical-assisted (plasma and microwave) processes, multistage reactors and catalyst patterning are also illustrated as the most promising perspective for CH4 reforming, especially on small and medium scale. Although these strategies should only be considered at a limited level of technological readiness, research on these topics, including catalyst development and process optimization, represents the crucial challenge for the scientific community
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Pre-clinical development of a lentiviral vector expressing the anti-sickling beta AS3 globin for gene therapy for sickle-cell disease
Towards 4-loop NSPT result for a 3-dimensional condensate-contribution to hot QCD pressure
Thanks to dimensional reduction, the contributions to the hot QCD pressure
coming from so-called soft modes can be studied via an effective
three-dimensional theory named Electrostatic QCD (spatial Yang-Mills fields
plus an adjoint Higgs scalar). The poor convergence of the perturbative series
within EQCD suggests to perform lattice measurements of some of the associated
gluon condensates. These turn out, however, to be plagued by large
discretization artifacts. We discuss how Numerical Stochastic Perturbation
Theory can be exploited to determine the full lattice spacing dependence of one
of these condensates up to 4-loop order, and sharpen our tools on a concrete
2-loop example.Comment: Presented at 25th International Symposium on Lattice Field Theory,
Regensburg, Germany, 30 Jul - 4 Aug 2007, 7 page
Non-destructive characterisation of a Villanovan sword using time-of-flight neutron diffraction
Non-destructive characterisation of a Villanovan sword using time-of-flight neutron diffraction
In the present work we report an example application of time-of-flight neutron diffraction for the non-destructive characterisation of ancient bronzes. A Villanovan sword tightly joined to its scabbard by corrosion has been investigated. Data on alloy composition of the different parts and information about the manufacturing techniques have been successfully achieved. The present study is part of an extensive non-destructive investigation program concerning bronze productions of Central Italy during the Iron Age
Determining concentration depth profiles in fluorinated networks by means of electric force microscopy
5 páginas, 6 figuras.-- et al.By means of electric force microscopy, composition depth profiles were measured with nanometric resolution for a series of fluorinated networks. By mapping the dielectric permittivity along a line going from the surface to the bulk, we were able to experimentally access to the fluorine concentration profile. Obtained data show composition gradient lengths ranging from 30 nm to 80 nm in the near surface area for samples containing from 0.5 to 5 wt. % F, respectively. In contrast, no gradients of concentration were detected in bulk. This method has several advantages over other techniques because it allows profiling directly on a sectional cut of the sample. By combining the obtained results with x-ray photoelectron spectroscopy measurements, we were also able to quantify F/C ratio as a function of depth with nanoscale resolution.L.A.M., M.M.K., G.A.S., A.A., and J.C. acknowledge
the financial support provided by the Basque Country Government
(Grant No. IT-436-07), the Spanish Ministry of Science
and Innovation (Grant Nos. MAT 2007-63681 and CSD 2006-
00053). The Donostia International Physics Center (DIPC) financial
support is also acknowledged.Peer reviewe
A brief overview on valorization of industrial tomato by-products using the biorefinery cascade approach
The industrial processing of tomato leads to substantial amounts of residues, typically known as tomato pomace or by-products, which can represent as much as 10% by weight of fresh tomatoes. At present, these residues are either used as feedstock for animals or, in the worst case, disposed of in landfills. This represents a significant waste because tomato pomace contains high-value compounds like lycopene, a powerful antioxidant, cutin, which can be used as a starting material for biopolymers, and pectin, a gelling agent. This article presents an overview of technologies that valorize tomato by-products by recovering added-value compounds as well as generating fuel for energy production. These technologies include operations for extraction, separation, and exploitation of lycopene, cutin and pectin, as well as the processes for conversion of the solid residues to fuels. Data collected from the review has been used to develop a biorefinery scheme with the related mass flow balance, for a scenario involving the tomato supply chain of Regione Campania in Italy, using tomato by-products as feedstock
The Grid-distributed data analysis in CMS
The CMS experiment will soon produce a huge amount of data (a few PBytes per year) that will be distributed and stored in many computing centres spread across the countries participating in the collaboration. Data will be available
to the whole CMS physicists: this will be possible thanks to the services provided by supported Grids. CRAB is the CMS collaboration tool developed to allow physicists to access and analyze data stored over world-wide sites. It aims to simplify the data discovery process and the jobs creation, execution and monitoring tasks hiding the details related both to Grid infrastructures and CMS analysis framework. We will discuss the recent evolution of this tool from its standalone version up to the clientserver
architecture adopted for particularly challenging workload volumes and we will report the usage statistics collected from the CRAB community, involving so far almost 600 distinct users
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