529 research outputs found
A recursive coupling-decoupling approach to improve experimental frequency based substructuring results
Substructure decoupling techniques allow identifying the dynamic behavior of a substructure starting from the dynamic behavior or the assembled system and a residual subsystem. Standard approaches rely on the knowledge of all FRFs at the interface DOFs between the two substructures. However, as these typically include also rotational DOFs which are extremely difficult and most of the time impossible to measure, several techniques have been investigated to overcome these limitations. A very attractive solution consists in defining mixed or pseudo interfaces, that allow to substitute unmeasurable coupling DOFs with internal DOFs on the residual substructure. Additionally, smoothing/denoising techniques have been proposed to reduce the detrimental effect of FRF noise and inconsistencies on the decoupling results. Starting from these results, some recent analysis on the possibility of combining coupling and decoupling FBS to validate the results and compensate for inconsistencies will be presented in this paper. The proposed method relies on errors introduced in the substructuring process when assuming that the interface behaves rigidly, while it is generally known that this assumption is seldom verified. Consequently, a recursive coupling-decoupling approach will be used to improve the estimation of the dynamic response of either the residual structure (for decoupling) or the assembly (for coupling). The method, validated on analytical data, will be here analyzed on a numerical example inspired by an experimental campaign used to validate the finite element models and on which standard substructuring techniques showed some limitations. The results discussed in this paper will be then used as guidelines to apply the proposed methodologies on experimental data in the future
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Mechanisms producing different precipitation patterns over northâeastern Italy: insights from HyMeXâSOP1 and previous events
During the first HyMeX Special Observation Period (SOP1) field campaign, the target site of northâeastern Italy (NEI) experienced a large amount of precipitation, locally exceeding the climatological values and distributed among several heavyârainfall episodes. In particular, two events that occurred during the last period of the campaign drew our attention. These events had common largeâscale patterns and a similar mesoscale setting, characterised by southerly lowâlevel flow interacting with the Alpine orography, but the precipitation distribution was very different. During Intensive Observing Period IOP18 (31 Octoberâ1 November 2012), convective systems were responsible for intense rainfall mainly located over a flat area of the eastern Po Valley, well upstream of the orography. Conversely, during IOP19 (4/5 November 2012), heavy precipitation affected only the Alpine area. In addition to IOP18 and IOP19, the present study analyses other heavyâprecipitation episodes that display similar characteristics and which occurred over NEI during the autumn of recent years. A highâresolution (2 km grid spacing) nonâhydrostatic NWP model and available observations are used for this purpose.
The two different observed precipitation patterns are explained in terms of interaction between the impinging flow and the Alps. Depending on the thermodynamic profile, convection can be triggered when the impinging flow is forced to rise over a preâexisting coldâair layer at the base of the orography. In this situation a persistent blockedâflow condition and upstream convergence are responsible for heavy rain localized over the plain. Conversely, if convection does not develop, flowâover conditions are established and heavy rain affects the Alps. Numerical parameters proposed in the literature are used to support the analysis.
Finally, the role of evaporative cooling beneath the convective systems is evaluated. It turns out that the stationarity of the systems upstream of the Alps is mainly attributable to persistent blockedâflow conditions, while convective outflow slightly modifies the location of precipitation
Man Is What He Eats: The Philosophy and Ethics of Eating
The article is based on Feuerbach's well-known ruling that "man is what he eats", to analyse its possible different meanings, even the most recondited ones. To do this the research winds through a long journey, which begins with a reflection on the role that food has in some Western religions, especially in Judaism and Christianity. Two processes which have deeply characterized the relationship of Western man with food are then examined: the process of industrialization and that of the medicalization of food. Finally, coming to the contemporary, the article goes into the merits of the relationship that different cultures have with food in a multicultural society and offers some indications for alternative models compared to those currently dominant. The conclusion, with Feuerbach and beyond Feuerbach, is that man is yes what he eats, but also what he does not eat and, above all, man eats what he is
Friction control with nematic lubricants via external fields
We study the connection between sliding friction and the phase behavior of a simple rigid bead-necklacemodel of a liquid crystal (LC) lubricant layer confined between two parallel plates. The dynamics is dependent on competing LC ordering mechanisms, including the direction of sliding, and an applied (electric) field. Together with temperature and an applied pressure, determining whether the lubricant is in a fluidlike isotropic state or in a layered in-plane nematic state, such ordering is found to control the frictional properties of the lubricant. Our extensive molecular dynamics simulations reveal in a detailed manner how friction can be controlled via applied fields. The results are expected to help in designing novel strategies to develop lubricants with dynamically controllable properties.Peer reviewe
The chronic intestinal ischemic disease in the elderly. Clinical - morphologic correlation study
Observational Mass-to-Light Ratio of Galaxy Systems: from Poor Groups to Rich Clusters
We study the mass-to-light ratio of galaxy systems from poor groups to rich
clusters, and present for the first time a large database for useful
comparisons with theoretical predictions. We extend a previous work, where B_j
band luminosities and optical virial masses were analyzed for a sample of 89
clusters. Here we also consider a sample of 52 more clusters, 36 poor clusters,
7 rich groups, and two catalogs, of about 500 groups each, recently identified
in the Nearby Optical Galaxy sample by using two different algorithms. We
obtain the blue luminosity and virial mass for all systems considered. We
devote a large effort to establishing the homogeneity of the resulting values,
as well as to considering comparable physical regions, i.e. those included
within the virial radius. By analyzing a fiducial, combined sample of 294
systems we find that the mass increases faster than the luminosity: the linear
fit gives M\propto L_B^{1.34 \pm 0.03}, with a tendency for a steeper increase
in the low--mass range. In agreement with the previous work, our present
results are superior owing to the much higher statistical significance and the
wider dynamical range covered (about 10^{12}-10^{15} M_solar). We present a
comparison between our results and the theoretical predictions on the relation
between M/L_B and halo mass, obtained by combining cosmological numerical
simulations and semianalytic modeling of galaxy formation.Comment: 25 pages, 12 eps figures, accepted for publication in Ap
Estudo de caso da avaliação dos riscos alimentares e ambientais da soja geneticamente modificada - método GMP-RAM para avaliação caso a caso dos riscos de plantas geneticamente modificadas.
A avaliação da segurança Ă© essencial para a pesquisa e desenvolvimento das plantas geneticamente modificadas (PGMs), incluindo a anĂĄlise dos riscos potenciais das plantas ou das prĂĄticas relacionadas ao seu cultivo para o meio ambiente e efeitos para a saĂșde humana e animal de maneira comparativa com a variedade convencional. O mĂ©todo GMP ? RAM (Risk Assessment Method for Genetically Modified Plants), Ă© a primeira metodologia para avaliação caso a caso dos riscos de PGMs, a partir desta anĂĄlise, possibilita a adoção de medidas para evitar ou controlar tal risco. A possibilidade de inserir indicadores especĂficos para a avaliação da PGM em questĂŁo e a necessidade de elaborar a lista de recomendaçÔes a partir dos resultados levantados permite uma anĂĄlise caso a caso do evento, neste trabalho foi realizado o estudo de caso da segurança alimentar e ambiental da Soja Roundup Read
A systematic approach to the Planck LFI end-to-end test and its application to the DPC Level 1 pipeline
The Level 1 of the Planck LFI Data Processing Centre (DPC) is devoted to the
handling of the scientific and housekeeping telemetry. It is a critical
component of the Planck ground segment which has to strictly commit to the
project schedule to be ready for the launch and flight operations. In order to
guarantee the quality necessary to achieve the objectives of the Planck
mission, the design and development of the Level 1 software has followed the
ESA Software Engineering Standards. A fundamental step in the software life
cycle is the Verification and Validation of the software. The purpose of this
work is to show an example of procedures, test development and analysis
successfully applied to a key software project of an ESA mission. We present
the end-to-end validation tests performed on the Level 1 of the LFI-DPC, by
detailing the methods used and the results obtained. Different approaches have
been used to test the scientific and housekeeping data processing. Scientific
data processing has been tested by injecting signals with known properties
directly into the acquisition electronics, in order to generate a test dataset
of real telemetry data and reproduce as much as possible nominal conditions.
For the HK telemetry processing, validation software have been developed to
inject known parameter values into a set of real housekeeping packets and
perform a comparison with the corresponding timelines generated by the Level 1.
With the proposed validation and verification procedure, where the on-board and
ground processing are viewed as a single pipeline, we demonstrated that the
scientific and housekeeping processing of the Planck-LFI raw data is correct
and meets the project requirements.Comment: 20 pages, 7 figures; this paper is part of the Prelaunch status LFI
papers published on JINST:
http://www.iop.org/EJ/journal/-page=extra.proc5/jins
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