11,718 research outputs found
Methodology for determining optimized traffic light cycles based on simulation
In large urbanized cities, a major problem that affects the economy and health of all citizens is vehicular congestion. This is because the traffic light cycles are not adequate. In the present study, we seek to optimize traffic light cycles based on simulation, in order to improve vehicle flow. For this, the PTV Vissim 9.0 software was used as a simulator and the Synchro 10.0 software to determine the initial optimal traffic light cycle. Through several runs and having as variables the length of queues, delay times and the average speed, the optimal traffic light cycle could be found for the study area. The results obtained reflect a 14% reduction in delay times and 10% in queue lengths. On the other hand, the average vehicle speed increased by 10.56%. All this represents an improvement in the service level of the study intersections
Commensurate-Incommensurate Magnetic Phase Transition in Magnetoelectric Single Crystal LiNiPO
Neutron scattering studies of single-crystal LiNiPO reveal a spontaneous
first-order commensurate-incommensurate magnetic phase transition. Short- and
long-range incommensurate phases are intermediate between the high temperature
paramagnetic and the low temperature antiferromagnetic phases. The modulated
structure has a predominant antiferromagnetic component, giving rise to
satellite peaks in the vicinity of the fundamental antiferromagnetic Bragg
reflection, and a ferromagnetic component giving rise to peaks at small
momentum-transfers around the origin at . The wavelength of the
modulated magnetic structure varies continuously with temperature. It is argued
that the incommensurate short- and long-range phases are due to
spin-dimensionality crossover from a continuous to the discrete Ising state.
These observations explain the anomalous first-order transition seen in the
magnetoelectric effect of this system
Conditional cash and in-kind transfers increase household total and food consumption in poor rural communities in Mexico
Remarks on the representation theory of the Moyal plane
We present an explicit construction of a unitary representation of the
commutator algebra satisfied by position and momentum operators on the Moyal
plane.Comment: 10 pages, minor changes, refs. adde
On the noncommutative eikonal
We study the eikonal approximation to quantum mechanics on the Moyal plane.
Instead of using a star product, the analysis is carried out in terms of
operator-valued wavefunctions depending on noncommuting, operator-valued
coordinates.Comment: 18 page
Effect of Charged Scalar Loops on Photonic Decays of a Fermiophobic Higgs
Higgs bosons with very suppressed couplings to fermions ("Fermiophobic Higgs
bosons", h_f) can decay to two photons (\gamma\gamma) with a branching ratio
significantly larger than that expected for the Standard Model Higgs boson for
m_{h_f}<150 GeV. Such a particle would give a clear signal at the LHC and can
arise in the Two Higgs Doublet Model (type I) in which h_f -> \gamma\gamma is
mediated by W^+ and charged Higgs boson (H^+) loops. We show that the H^+ loops
can cause both constructive and destructive contributions with a magnitude
considerably larger than the anticipated precision in the measurement of the
photonic decay channel at future hadron and lepton colliders.Comment: 18 pages, 5 figures, clarifications added, one reference added,
accepted by Physical Review
Impact-Induced Clay Mineral Formation and Distribution on Mars
Clay minerals have been identified in the central peaks and ejecta blankets of impact craters on Mars. Several studies have suggested these clay minerals formed as a result of impact induced hydrothermalism either during Mars' Noachian era or more recently by the melting of subsurface ice. Examples of post-impact clay formation is found in several locations on Earth such as the Mjolnir and Woodleigh Impact Structures. Additionally, a recent study has suggested the clay minerals observed on Ceres are the result of impact-induced hydrothermal processes. Such processes may have occurred on Mars, possibly during the Noachian. Distinguishing between clay minerals formed preor post-impact can be accomplished by studying their IR spectra. In fact, showed that the IR spectra of clay minerals is greatly affected at longer wavelengths (i.e. mid-IR, 5-25 micron) by impact-induced shock deformation while the near-IR spectra (1.0-2.5 micron) remains relatively unchanged. This explains the discrepancy between NIR and MIR observations of clay minerals in martian impact craters noted. Thus, it allows us to determine whether a clay mineral formed from impact-induced hydrothermalism or were pre-existing and were altered by the impact. Here we study the role of impacts on the formation and distribution of clay minerals on Mars via a fully 3-D Monte Carlo cratering model, including impact- melt production using results from modern hydrocode simulations. We identify regions that are conducive to clay formation and the location of clay minerals post-bombardment
Energy and Exergy Analysis of Water-LiBr Absorption Systems with Adiabatic Absorbers for Heating and Cooling
AbstractSolar energy can be used to produce cold through absorption systems. In this study, the energy and exergy analysis on a single effect water-LiBr absorption facility is presented. The work is carried out for heating and cooling applications. Performance parameters are the coefficient of performance and exergy efficiency. The influence of operating temperatures on such parameters is included. An analysis of individual components is also presented. The most noticeable effect is observed for the case of exergy efficiency for absorber and generator. This parameter increases with an increase of absorption temperature. The opposite effect is observed when the generation temperature increases. Results obtained allow the identification of parameters that may influence the exergy efficiency of the adiabatic absorption system. The first candidate to optimize is the absorber, due to the lowest value of exergy efficiency obtained among all components of the system. For adiabatic absorbers, the recirculation ratio emerges as a new parameter. The solution heat exchanger is also susceptible to optimization
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