6,781 research outputs found
An alternative methodology to predict aging effects on the mechanical properties of glass fiber reinforced cement (GRC)
The effect of three different aging methods (immersion in hot water, freezeâthaw cycles and wetâdry cycles) on the mechanical properties of GRC were studied and compared.
Test results showed that immersion in hot water may be an unreliable method for modified GRC formulations, with it being in probability a very harmful procedure.
A new aging method, mixing freezeâthaw cycles and wetâdry cycles, seems to be the most accurate simulation of weather conditions that produce a noticeable change in GRC mechanical properties. Future work should be carried out to find a correlation between real weather and the proposed aging method
Impact of introducing ecoinnovation measures on productivity in transport sector companies
The transport and storage sector, like other sectors of the Spanish
economy, is experiencing the effects of the current economic crisis.
The Annual Services Survey prepared by the Spanish National Institute
of Statistics (INE) shows that between 2008 and 2013 there was an
11.9% reduction in turnover and an 18.3% reduction in paid workers
in companies in sector. However, in the same period, there was a 7.8%
increase in labour productivity.
The main aim of this study was to determine the impact of factors
related to innovation and the environment, among others, on labour
productivity in the Spanish transport and storage sector. Few studies
are available on this topic, which is most likely due to the scant
statistical information available for the sector analysed. The structural
analysis model used in this study was an extended version of the wellknown
CobbâDouglas production function applied to data obtained
from the Technological Innovation Panel (PITEC). PITEC is a panel type
database (for 2003â2013), which was developed jointly by the Spanish
National Institute of Statistics (INE) and the Spanish Foundation for
Science and Technology.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
Dynamic transition in Landau-Zener-St\"uckelberg interferometry of dissipative systems: the case of the flux qubit
We study Landau-Zener-Stuckelberg (LZS) interferometry in multilevel systems
coupled to an Ohmic quantum bath. We consider the case of superconducting flux
qubits driven by a dc+ac magnetic fields, but our results can apply to other
similar systems. We find a dynamic transition manifested by a symmetry change
in the structure of the LZS interference pattern, plotted as a function of ac
amplitude and dc detuning. The dynamic transition is from a LZS pattern with
nearly symmetric multiphoton resonances to antisymmetric multiphoton resonances
at long times (above the relaxation time). We also show that the presence of a
resonant mode in the quantum bath can impede the dynamic transition when the
resonant frequency is of the order of the qubit gap. Our results are obtained
by a numerical calculation of the finite time and the asymptotic stationary
population of the qubit states, using the Floquet-Markov approach to solve a
realistic model of the flux qubit considering up to 10 energy levels.Comment: One new figure added. Final version to be published in PR
Top-antitop resonance searches beyond 1 TeV
We perform a general parton level analysis for the search of heavy resonant
states in the production of top-antitop pairs at the LHC with an integrated
luminosity of 30 fb^-1. We assume the existence of resonances that only couple
to quarks and propose kinematic cuts in order to increase the amount of events
produced through quark-annihilation. We study the interplay between different
variables and their impact on the purity of the selected sample. We make focus
on the longitudinal () and transverse () momentum of the
top-antitop pair, and the scattering angle () in the center of mass
reference frame. We observe that is replaced by as a suitable
discriminating variable of quark-annihilation processes for invariant masses
above 1 TeV. Finally, we illustrate the analysis with a gluon resonance of 1.5
TeV and show the improvement in the sensitivity of the signal when cuts on
are imposed.Comment: 19 pages and 6 figure
An integrative approach for modeling and simulation of Heterocyst pattern formation in Cyanobacteria strands
A comprehensive approach to cellular differentiation in cyanobacteria is
developed. To this aim, the process of heterocyst cell formation is studied
under a systems biology point of view. By relying on statistical physics
techniques, we translate the essential ingredients and mechanisms of the
genetic circuit into a set of differential equations that describes the
continuous time evolution of combined nitrogen, PatS, HetR and NtcA
concentrations. The detailed analysis of these equations gives insight into the
single cell dynamics. On the other hand, the inclusion of diffusion and noisy
conditions allows simulating the formation of heterocysts patterns in
cyanobacteria strains. The time evolution of relevant component concentrations
are calculated allowing for a comparison with experiments. Finally, we discuss
the validity and the possible improvements of the model.Comment: 20 pages (including the supporting information), 8 figure
Curvature as a Measure of the Thermodynamic Interaction
We present a systematic and consistent construction of geometrothermodynamics
by using Riemannian contact geometry for the phase manifold and harmonic maps
for the equilibrium manifold. We present several metrics for the phase manifold
that are invariant with respect to Legendre transformations and induce
thermodynamic metrics on the equilibrium manifold. We review all the known
examples in which the curvature of the thermodynamic metrics can be used as a
measure of the thermodynamic interaction
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