1,721,287 research outputs found
Validation of numerical models for hospital building contents: rigid blocks and FEM models
No full textThe post-earthquake functionality of hospital buildings is an essential performance objective to achieve in a modern resilient community (Bruneau and Reinhorn, 2007). Such a performance may, however, be impaired due to the damage to non-structural components and building contents. Recent surveys carried out in the aftermath of major world-wide earthquakes (e.g. (Di Sarno et al., 2013, Jacques et al., 2014, Masi et al., 2014, among others) have shown that the overturning of cabinets, containing medical files with patient details, the failure of electronic panels is a typical non-structural component damage recorded after moderate-to-large earthquakes. Hazardous contaminants may also be released when medical cabinets and bookshelves overturn; hence there is a number of dangerous consequences caused by the lack of adequate seismic design. Comprehensive experimental and numerical studies were carried out in the last decade to investigate the seismic performance of a variety of furniture items, medical appliances and service utilities of typical hospital buildings and pharmacies, e.g. (Cosenza et al., 2014, Furukawa et al., 2013, Kuo et al., 2011). Numerical modeling of such components is still a key issue to be addressed.
In this study, simplified finite element models of the tested components have also been implemented in software platforms to adequately simulate the dynamic properties of sample medical components. Different numerical modeling approaches are validated upon the outcomes of a comprehensive experimental campaign on hospital building contents carried out by shake table testing at the University of Naples Federico II, Italy.
Finite element modeling approach is adopted to investigate the dynamic behavior of hospital cabinets in case they do not exhibit any rocking mechanism, i.e. pre-rocking behavior. The validation of a FEM model for the dynamic performance of cabinets is presented. Its ability to reproduce horizontal acceleration in the cabinets is also discussed. The developed numerical model gave a fairly good matching in terms of natural frequencies of the sample components. Nonlinear dynamic analyses are performed on the defined models. Recorded table acceleration are applied at the base of both the cabinets for the three different test groups. It is concluded that the defined model is able to recognize the occurrence of the rocking mechanism in the cabinets.
Medical components, such as the tested cabinets, typically exhibits a rocking behavior as the seismic intensity increases. Thus, the dynamic behavior of rigid blocks is investigated for the post-rocking behavior of cabinets. Tested cabinets are modelled as equivalent rigid blocks and subjected to the experimental base accelerations. The ability to predict the occurrence of both rocking mechanism and overturning is verified. Given the good model fidelity, a preliminary study is performed aimed at the identification of the most efficient seismic intensity measure (IM) for rigid blocks and the influence of the geometric properties of rigid blocks on their dynamic performanc
Validation of numerical model for hospital building contents: rigid block and FEM models
No full textIn this study, simplified finite element models of the tested components have also been implemented in software platforms
to adequ
ately simulate the dynamic properties of sample medical components. Different numerical modeling approaches are
validated upon the outcomes of a comprehensive experimental campaign on hospital building contents carried out by shake
table testing at the Uni
versity of Naples Federico II, Italy.
Finite element modeling approach is adopted to investigate the dynamic behavior of hospital cabinets in case they do not
exhibit any rocking mechanism, i.e. pre
-rocking behavior. The validation of a FEM model for the d
ynamic performance of
cabinets is presented. Its ability to reproduce horizontal acceleration in the cabinets is also discussed. The developed
numerical model gave a fairly good matching in terms of natural frequencies of the sample components. Nonlinear dynamic
analyses are performed on the defined models. Recorded table acceleration are applied at the base of both the cabinets for
the three different test groups. It is concluded that the defined model is able to recognize the occurrence of the rocking
me
chanism in the cabinets.
Medical components, such as the tested cabinets, typically exhibits a rocking behavior as the seismic intensity increases.
Thus, the dynamic behavior of rigid blocks is investigated for the post
-rocking behavior of cabinets. Tested cabinets are
modelled as equivalent rigid blocks and subjected to the experimental base accelerations. The ability to predict the
occurrence of both rocking mechanism and overturning is verified. Given the good model fidelity, a preliminary study is
perf
ormed aimed at the identification of the most efficient seismic intensity measure (IM) for rigid blocks and the influence
of the geometric properties of rigid blocks on their dynamic performance
Seismic demand on light-acceleration-sensitive nonstructural components in European reinforced concrete buildings
No full textThe seismic performance of nonstructural com
ponents is nowadays recognized as one of the most critical issues
related to
the performance
-based earthquake engineering.
In order to obtain
an adequate seismic design of nonstructural components,
a cons
istent estimation of the seismic demand is essential. Recent studies have shown that current international building
codes provide unreliable approaches to the evaluation of acceleration floor spectra. This paper examines the seismic demand
on light acceler
ation
-sensitive nonstructural components caused by frequent earthquake
through an accurate parametric
study
. In this work, a number of reinforced concrete frame structures are designed according to Eurocode 8 and subjected to
a set of frequent earthquakes,
i.e. 63% probability of exceeda
nce in 50 years.
In order to assess the reliability of Eurocode 8
formulations, dynamic nonlinear analysis have been performed on a set of reference
structures. It is
found
that Eurocode 8
significantly underestimates the acceleration demand for a wide range of periods. An alternative method to estimate f
loor
acceleration demands in mul
ti-story buildings is presented through the proposal of a new formulation that is able to better
predict the actual acceleration demand
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Performance of the stretched-and vibrating-wire techniques and correction of background fields in locating quadrupole magnetic axes
No full textA single conducting wire is used for localizing the magnetic axis of a quadrupole magnet. The localization is performed by both the stretched-wire and the vibratingwire method. The compatibility of the two measurements is demonstrated and the measurement repeatability is assessed for both the methods at varying the magnet gradient. Furthermore, the influence of the background magnetic field in the two approaches is studied at varying the magnetic field strength. Experimental results are given for a normalconducting quadrupole magnet
Data-driven simulation of transient fields in air–coil magnets for accelerators
No full textTime-varying fields in fast-ramping magnets for accelerators are difficult to compute in the range of accuracy required for magnet operation. This is due to the complexity of the dynamic phenomena such as hysteresis and 3D eddy currents. On the other hand, magnetic measurements that intercept all these physical phenomena are often limited to a subset of excitation cycles and restricted spatial domains. The measurement results are therefore difficult to extrapolate without a validated physical model of the device. This paper proposes measurement-updated field simulations to characterize dynamic effects in accelerator magnets. The main idea is to construct a reduced-order model, whose variables are retrievable from measurements by means of a state estimator, and to update the model by minimizing the error between simulations and measurements. The proposed method is applied to a linear, time-transient electromagnetic-field problem of an air–coil corrector magnet with aluminium collars. The proposed method is a first step towards a hybrid twin of an accelerator magnet
A mechanical analysis of rotating-coil magnetometers
No full textRotating-coil magnetometers are among the most common and most accurate transducers for measuring the integral magnetic-field harmonics in accelerator magnets. The measurement uncertainty depends on the mechanical properties of the shafts, bearings, drive systems, and supports. In this paper we study the mechanical phenomena (static and dynamic) affecting rotating-coil measurements and propose analysis and diagnostic methods for improving the instrument in terms of material choice and geometrical design. The propagation of uncertainty is investigated on the measured quantities (induced voltages, integrated and developed into a Fourier series, the coefficients of which are know as field harmonics). This results in a consistent framework for the design of a measurement bench for rotating-coil magnetometers. The paper also presents the design of a complete system, including displacement stages, supports, rotating coils, and an angular position system
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