950 research outputs found
INFLUENCE OF BOND-SLIP ON NUMERICAL FRAGILITY CURVES AND STRUCTURAL RELIABILITY OF RC STRUCTURAL INTERNAL BEAM-COLUMN SUB-ASSEMBLY
In this paper results obtained from monotonic nonlinear static analyses performed on Re-inforced Concrete (RC) internal beam-column sub-assembly are shown. Bond-slip phenome-non between steel longitudinal bars and surrounding concrete is also taken into account in order to predict the numerical response under lateral actions of the RC internal beam-column sub-assembly investigated.
The study is addressed, through parametric models and Monte Carlo simulations, to pro-pose preliminary fragility curves for different damage states of the RC internal beam-column sub-assembly, including materials inherent uncertainties
Seismic risk analysis on masonry buildings damaged by LâAquila 2009 and Emilia 2012 earthquakes
Earthquakes in the recent past continue to provide more and more information on the seismic behavior of existing buildings and on the related economic losses. For the reason it is interesting to compare the damage of buildings stocks archived after earthquakes survey activities. In this paper a study of the damage occurred on masonry buildings after LâAquila 2009 and Emilia 2012 earthquakes is carried out, by considering the data available in the web-gis Da.D.O platform. Firstly, fragility curves are illustrated and compared by considering the vulnerability classes of Da.D.O. (Class A, Class B and Class C1). Then, an approach is proposed in order to evaluate the total Expected Annual Loss (EALtot) and its contributions due to the several damage level (D1, âŠ, D5). The preliminary obtained results show that, with reference to the two masonry buildings stocks considered, the higher contribution to the (EALtot) is given by the damage level D3, that may be considered as the life safety limit state. In the case analyzed, the corresponding EALD3 results almost equal to 1/3 of EALtot
Typological seismic losses assessment by damaged masonry buildings after LâAquila 2009 and Emilia 2012 earthquakes
In this paper a seismic risk analysis of masonry buildings based on damage data from the 2009 L'Aquila and 2012 Emilia earthquakes. The seismic vulnerability is described by fragility curves from which economic loss curves are derived for each representative typological class of masonry buildings. The information on the buildings was collected by the Italian Civil Protection Department with the AeDES form and available in the Observed Damage Database (D.a.D.O.). The reliability of the database considered, however, was improved by carrying out a process of estimating undamaged buildings from data from the 15th ISTAT census. Finally, for each damage level, according to EMS-98 scale, a procedure to derive the Expected Annual Loss is presented, so as to express its percentage contribution in the seismic risk assessment
Decentralized Triangular Guidance Algorithms for Formations of UAVs
This paper deals with the design of a guidance control system for a swarm of unmanned aerial systems flying at a given altitude, addressing flight formation requirements that can be formulated constraining the swarm to be on the nodes of a triangular mesh. Three decentralized guidance algorithms are presented. A classical fixed leaderâfollower scheme is compared with two alternative
schemes: the former is based on the self-identification of one or more time-varying leaders; the latter is an algorithm without leaders. Several operational scenarios have been simulated involving swarms with obstacles and an increasing number of aircraft in order to prove the effectiveness of the proposed guidance schem
Current oscillations in a metallic ring threaded by a time-dependent magnetic flux
We study a mesoscopic metallic ring threaded by a magnetic flux which varies
linearly in time PhiM(t)=Phi t with a formalism based in Baym-Kadanoff-Keldysh
non-equilibrium Green functions. We propose a method to calculate the Green
functions in real space and we consider an experimental setup to investigate
the dynamics of the ring by recourse to a transport experiment. This consists
in a single lead connecting the ring to a particle reservoir. We show that
different dynamical regimes are attained depending on the ratio hbar Phi/Phi0
W, being Phi0=h c/e and W, the bandwidth of the ring. For moderate lengths of
the ring, a stationary regime is achieved for hbar Phi/Phi0 >W. In the opposite
case with hbar Phi/Phi0 < W, the effect of Bloch oscillations driven by the
induced electric field manifests itself in the transport properties of the
system. In particular, we show that in this time-dependent regime a tunneling
current oscillating in time with a period tau=2piPhi0/Phi can be measured in
the lead. We also analyze the resistive effect introduced by inelastic
scattering due to the coupling to the external reservoir.Comment: 17 pages, 13 figure
Quantum transport and momentum conserving dephasing
We study numerically the influence of momentum-conserving dephasing on the
transport in a disordered chain of scatterers. Loss of phase memory is caused
by coupling the transport channels to dephasing reservoirs. In contrast to
previously used models, the dephasing reservoirs are linked to the transport
channels between the scatterers, and momentum conserving dephasing can be
investigated. Our setup provides a model for nanosystems exhibiting conductance
quantization at higher temperatures in spite of the presence of phononic
interaction. We are able to confirm numerically some theoretical predictions.Comment: 7 pages, 4 figure
Tuning a Resonance in the Fock Space: Optimization of Phonon Emission in a Resonant Tunneling Device
Phonon-assisted tunneling in a double barrier resonant tunneling device can
be seen as a resonance in the electron-phonon Fock space which is tuned by the
applied voltage. We show that the geometrical parameters can induce a symmetry
condition in this space that can strongly enhance the emission of longitudinal
optical phonons. For devices with thin emitter barriers this is achieved by a
wider collector's barrier.Comment: 4 pages, 3 figures. Figure 1 changed, typos correcte
Accuracy of a method based on atomic absorption spectrometry to determine inorganic arsenic in food : Outcome of the collaborative trial IMEP-41
Peer reviewedPublisher PD
Magneto-transport in periodic and quasiperiodic arrays of mesoscopic rings
We study theoretically the transmission properties of serially connected
mesoscopic rings threaded by a magnetic flux. Within a tight-binding formalism
we derive exact analytical results for the transmission through periodic and
quasiperiodic Fibonacci arrays of rings of two different sizes. The role played
by the number of scatterers in each arm of the ring is analyzed in some detail.
The behavior of the transmission coefficient at a particular value of the
energy of the incident electron is studied as a function of the magnetic flux
(and vice versa) for both the periodic and quasiperiodic arrays of rings having
different number of atoms in the arms. We find interesting resonance properties
at specific values of the flux, as well as a power-law decay in the
transmission coefficient as the number of rings increases, when the magnetic
field is switched off. For the quasiperiodic Fibonacci sequence we discuss
various features of the transmission characteristics as functions of energy and
flux, including one special case where, at a special value of the energy and in
the absence of any magnetic field, the transmittivity changes periodically as a
function of the system size.Comment: 9 pages with 7 .eps figures included, submitted to PR
Comparison of mid-latitude single- And mixed-phase cloud optical depth from co-located infrared spectrometer and backscatter lidar measurements
The long-wave downwelling spectral radiance measurements performed by means of the Far-Infrared Radiation Mobile Observation System (FIRMOS) spectrometer at the summit of the Zugspitze (German Alps) in the winter 2018/19 allowed the retrieval of the optical and micro-physical properties of ice and mixed clouds, showing a good agreement of the statistical relationship between the ice water path and the ice optical depth with the ones from previous works. In this paper the optical depths retrieved from FIRMOS are initially compared with selected cases calculated from backscattering light detection and ranging (lidar) data by using a transmittance method. Then, in order to compare the whole FIRMOS dataset, the power-law relationship between backscattering and extinction is used to apply the Klett method and automatize the routine. Minimizing the root mean square differences, the exponent k of the power-law relationship is assessed to be 0.85 with a variability in the range of 0.60â1.10 for ice clouds and 0.50 with a variability within 0.30â0.70 for mixed clouds
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