1,720,985 research outputs found
How Far from a Building Does the Ground-Motion Free-Field Start? The Cases of Three Famous Towers and a Modern Building
No full textIt is well known that artificially inducing large amplitude vibrations on buildings produces seismic waves that are detectable up to a few kilometers away. Does a similar effect occur with seismic tremors? If the tremor wave field were perturbed by the presence of buildings, passive surveys in a urban environment would be potentially impaired. The literature is rather inconclusive on this issue. We experimentally analyzed the cases of three of the most famous Italian towers: the leaning tower of Pisa, the bell tower of San Marco in Venice, and the Asinelli tower in Bologna. We also analyzed a large modern 16 story residential building. Even performing the measurements in windy days, we found no cases in which the large structures perturb the free-field tremor at distances larger than 12 m. This confirms what was expected from simple dimensional analysis and suggests that passive soil–structure interaction is of little concern for standard buildings and standard ambient condition
The magnitude conversion problem: further insights
No full textIn 2007, Castellaro and Bormann (2007) studied the performance of various
two-dimensional (2D) regressions between different magnitude scales by mathematical
simulations. The study consisted in (1) generating sets of magnitude pairs
xi; yi with given true slope βtrue following a Gutenberg–Richter distribution with
b 1 and by adding initial errors ui; ei; (2) studying how far the slopes β obtained
in those data sets by standard βSR, inverted standard βISR, orthogonal βOR, and generalized
orthogonal βGOR regressions were from βtrue. Studies assessing the best
regression method are important because the misuse of the common standard regression
easily leads to magnitude conversion errors of 0.2–0.3 units. A different approach
to the magnitude conversion problem was proposed before Castellaro and Bormann’s
(2007) work and was based on the χ2 method, which is based on the theory of independent
and normally distributed errors ui; ei and xi. In this work, we derive
mathematical explanations for the results of Castellaro and Bormann (2007) in terms
of the χ2 method and find that results agree for mean initial errors <0:5 magnitude
units. Our results demonstrate the importance of knowing and taking into consideration
the true initial errors in regression analysis
Synthesis and NMR investigation of model molecules for glycosylation reactions of glycopolymers
No full textSynthesis and NMR investigation of styrene glycopolymers containing D-galactose units functionalized with 4-(4-hydroxybutoxy)benzylamine residues
No full textAs a part of a work aimed at the synthesis of properly functionalized nanostructured glycopolymers suitable for interaction studies with copper amine oxidases, D-galactose was transformed through a six step sequence into monomer N-(4-vinylbenzoyl)-6-amino-6-deoxy-D-galactose (1) which was converted into nanostructured crosslinked polymers (R1) by radical precipitation polymerization and into linear polymers (P1) by solution polymerization. The linear polymers were useful models for setting up glycosylation reactions to introduce N-trifluoroacetyl-4-(4-hydroxybutoxy)benzylamine residues in the presence of camphor sulfonic acid as catalyst and to extend them to the nanostructured systems. The advancement of the glycosylation reaction was performed through the synthesis and glycosylation of N-benzoyl-6-amino-6-deoxy-D-galactose (9) as model molecule for accurate NMR investigations. The removal of the trifluoroacetyl protecting group, unexpectedly stable, in glycosylated P1 and R1 was achieved with sodium borohydride
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
Detection of seismic damage on a RC building using the proportional flexibility-resembling matrix
No full textWhen an existing civil structure experiences a significant seismic event, permanent reductions of stiffness may be induced, thus resulting in changes in its dynamic behavior. Ambient vibration surveys performed before and after a seismic event are thus useful tools for the inspection and management process of the structure. A vibration-based approach for damage detection and localization has been developed by the authors in previous research. This approach is based on estimating a matrix that approximates a proportional flexibility matrix, termed proportional flexibility-resembling (PFR) matrix. This matrix is computed through signal processing operations to be executed after applying the first steps of the Frequency-Domain Decomposition technique. The main feature of the PFR matrix, compared to the traditional modal flexibility matrix, is that it can be assembled without the need of an explicit identification of the modal parameters. The matrix is in fact obtained by processing all first singular vectors and also all first singular values in a selected frequency range. In previous research by the authors the approach has been validated through numerical simulations and using the experimental data of laboratory tests performed on a small-scale frame structure. The objective of this contribution is to test the approach based on the PFR matrix on a full-scale reinforced concrete (RC) building structure that has experienced seismic damage. This structure was tested on the large-scale Network for Earthquake Engineering Simulation (NEES) shaking table of the University of California, San Diego (UCSD). During the experimental tests, some historical earthquake records were applied at the base of the building structure, and this induced progressively increasing levels of damage. After each strong motion test, low-amplitude vibration tests were performed for damage characterization purposes
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
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