4,855 research outputs found
Capacity assessment of multi-storey RC walls
Phase 2 of the CASH benchmark was dedicated to the response prediction of multi-storey reinforced concrete (RC) walls used as seismic resisting members in nuclear power plants. Nonlinear static and dynamic analyses have been carried out to check the reliability of non-linear finite element analysis (NLFEA) to assess the seismic capacity of reinforced concrete walls. Authors attended the benchmark by modelling RC walls using multi-layered shell elements and by adopting a self implemented crack model. The paper describes modelling strategies and some critical issues of the Eurocode 8 prescrip-tions for the shear demand and shear capacity evaluation of multi-storey RC walls
Growth in emerging economies: is there a role for education?
We study the relationship between human capital and growth using a model which encompasses previous specifications and estimates the short and the long-run effects of human capital accumulation. We adopt an empirical framework which accounts for countries’ heterogeneity and cross-sectional dependence in a dynamic panel. Results for a sample of 14 Asian countries reveal a large and positive long-run impact of human capital on growth in the 1960-2013 period. Looking at different types of education we find that the diffusion of primary and secondary education has a positive long-run impact, while the long-run effect of tertiary education is negative. Low proportion of people educated at the tertiary level, lack of opportunities for highly educated workers and the brain drain phenomenon could explain this result. These results support policies directed towards increasing investments in primary and secondary education rather than focusing on a minority educated at the tertiary level
Certified and uncertified skills and productivity growth performance: cross-country evidence at industry level
We analyse the relationship between human capital and productivity growth using a five-country multi-industry dataset together with a measure of human capital which accounts for both certified skills (educational qualifications) and uncertified skills acquired through on-the-job training and experience. We find evidence of positive human capital effects on growth in average labour productivity, particularly when using our composite human capital measure. We also find some tentative evidence that multi-factor productivity (MFP) growth is positively related to the use of high-skilled labour. However, externalities of this kind are largely confined to industries which make intensive use of university graduates. (abstract as appears on publisher website
Birds, Ilha Grande, state of Rio de Janeiro, Southeastern Brazil
We provide a list of bird species from our primary surveys and secondary data for an island (Ilha Grande) insoutheastern Brazil. The information derives mainly from primary data collected since 1995, particularly in the oceanicside of the island. The methodologies included capture-mark-recapture studies using mist nets, transects (visual andvocal records) and supplementary observations. Our total species list from primary data is 175 species (127 captured)and 47 species were added from secondary data. This represents 222 species from 58 families. Of this total, 44 areendemic to Atlantic forest and nine are threatened with extinction. Our results are discussed comparing our study areawith another large island included in the Serra do Mar corridor (Ilha de SĂŁo SebastiĂŁo), and also a nearby continentalarea (Paraty). The results indicate the importance of Ilha Grande as a reservoir of bird species of Atlantic forest
NUMERICAL EVALUATION OF THE CORROSION EFFECTS IN PRESTRESSED CONCRETE BEAMS WITHOUT SHEAR REINFORCEMENT
Corrosion of prestressed concrete structures causes size reduction of
strands, degradation of mechanical properties of steel, cracking of the
surrounding concrete and bond decay at steel-to-concrete interface. In
this paper, a numerical approach able to take into account all the effects
involved in the corrosion process by using non-linear finite element
analysis (NLFEA) and membrane or shell elements modelling, is
proposed. Two different strategies are adopted to model strands: the
smeared and the discrete approaches. The results obtained using these
latter strategies are validated by comparing NLFEA results with
experimental measurements of a naturally corroded prestressed beam
tested at the “Instituto de Ciencias de la Construcción Eduardo Torroja”
in Madrid. Finally, pros and cons of the proposed modelling approach are
critically analysed, demonstrating that considering the actual spatial
corrosion distribution is necessary to predict the position where failure
occurs
The effect of musical expertise on the representation of space
Consistent evidence suggests that pitch height may be represented in a spatial format, having both a vertical and a horizontal representation. The spatial representation of pitch height results into response compatibility effects for which high pitch tones are preferentially associated to up-right responses, and low pitch tones are preferentially associated to down-left responses (i.e., the Spatial-Musical Association of Response Codes (SMARC) effect), with the strength of these associations depending on individuals’ musical skills. In this study we investigated whether listening to tones of different pitch affects the representation of external space, as assessed in a visual and haptic line bisection paradigm, in musicians and non musicians. Low and high pitch tones affected the bisection performance in musicians differently, both when pitch was relevant and irrelevant for the task, and in both the visual and the haptic modality. No effect of pitch height was observed on the bisection performance of non musicians. Moreover, our data also show that musicians present a (supramodal) rightward bisection bias in both the visual and the haptic modality, extending previous findings limited to the visual modality, and consistent with the idea that intense practice with musical notation and bimanual instrument training affects hemispheric lateralization
Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen
We report the properties of sodium (Na) and aluminum (Al) cosmic rays in the rigidity range 2.15 GV to 3.0 TV based on 0.46 million sodium and 0.51 million aluminum nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. We found that Na and Al, together with nitrogen (N), belong to a distinct cosmic ray group. In this group, we observe that, similar to the N flux, both the Na flux and Al flux are well described by the sums of a primary cosmic ray component (proportional to the silicon flux) and a secondary cosmic ray component (proportional to the fluorine flux). The fraction of the primary component increases with rigidity for the N, Na, and Al fluxes and becomes dominant at the highest rigidities. The Na /Si and Al /Si abundance ratios at the source, 0.036 ±0.003 for Na /Si and 0.103 ±0.004 for Al /Si , are determined independent of cosmic ray propagation
Design and advancement status of the Beam Expander Testing X-ray facility (BEaTriX)
The BEaTriX (Beam Expander Testing X-ray facility) project is an X-ray
apparatus under construction at INAF/OAB to generate a broad (200 x 60 mm2),
uniform and low-divergent X-ray beam within a small lab (6 x 15 m2). BEaTriX
will consist of an X-ray source in the focus a grazing incidence paraboloidal
mirror to obtain a parallel beam, followed by a crystal monochromation system
and by an asymmetrically-cut diffracting crystal to perform the beam expansion
to the desired size. Once completed, BEaTriX will be used to directly perform
the quality control of focusing modules of large X-ray optics such as those for
the ATHENA X-ray observatory, based on either Silicon Pore Optics (baseline) or
Slumped Glass Optics (alternative), and will thereby enable a direct quality
control of angular resolution and effective area on a number of mirror modules
in a short time, in full X-ray illumination and without being affected by the
finite distance of the X-ray source. However, since the individual mirror
modules for ATHENA will have an optical quality of 3-4 arcsec HEW or better,
BEaTriX is required to produce a broad beam with divergence below 1-2 arcsec,
and sufficient flux to quickly characterize the PSF of the module without being
significantly affected by statistical uncertainties. Therefore, the optical
components of BEaTriX have to be selected and/or manufactured with excellent
optical properties in order to guarantee the final performance of the system.
In this paper we report the final design of the facility and a detailed
performance simulation.Comment: Accepted paper, pre-print version. The finally published manuscript
can be downloaded from http://dx.doi.org/10.1117/12.223895
Il fenomeno del buckling implementato nel modello fessurativo PARC_CL 2.1
Gli edifici esistenti in calcestruzzo armato, progettati prima delle attuali normative sismiche, presentano solitamente un’armatura traversale ridotta o assente che causa un cattivo confinamento dell’armatura longitudinale. Durante il sisma le armature longitudinali possono essere sottoposte ad elevate deformazioni che possono indurre lo svergolamento (“buckling”). Si rende dunque necessario l’utilizzo di un modello costitutivo per l’acciaio capace di simulare realisticamente il fenomeno del buckling. I modello analizzati nel presente lavoro sono quello formulati da Monti-Nuti e da Kashani implementati nel modello fessurativo PARC_CL 2.1. Sono stati quindi analizzati elementi in calcestruzzo armato sottoposti a carichi ciclici con caratteristiche geometriche e meccaniche tipi-che degli edifici costruiti negli anni ’70 (pre normativa sismica), simulandone il comportamento con entrambi i modelli proposti.Reinforced concrete (RC) structures, designed and built before the modern seismic codes, typically present an un-derestimated transversal reinforcement, that causes a bad confinement for the longitudinal rebars. During earthquake, longitudinal reinforcement could be subjected to high deformations inducing buckling. It is therefore necessary using a constitutive model able to realistically simulate the buckling phenomenon. In the present work, the Monti-Nuti model and the Kashani model has been ana-lyzed and implemented in the PARC_CL 2.1 crack model. Then, RC elements subjected to cyclic loads with mechanical and geo-metrical characteristics typical of 70’s buildings in Italy (before seismic codes) have been analyzed with the two proposed models.
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