1,618 research outputs found
A Multi-Motor Architecture for Electric Vehicles
This paper proposes an architecture for EVs with three or more electric motors and highlights when adding more motors does not impact the battery state of charge (SOC). The proposed control algorithm optimizes the use of the motors onboard to keep them running in their most efficient regions. Simulation results along with a comparison with other current motors used in EVs is presented in this paper, and further discussion on the results is presented. With this architecture, the powertrain would see a combined efficiency map that incorporates the best operating points of the motors. Therefore, the proposed architecture will allow the EV to operate with a higher range for a given battery capacity
Muonium spectrum beyond the nonrelativistic limit
A generalization of the Gell-Mann-Low theorem is applied to the
antimuon-electron system. The bound state spectrum is extracted numerically. As
a result, fine and hyperfine structure are reproduced correctly near the
nonrelativistic limit (and for arbitrary masses). We compare the spectrum for
the relativistic value alpha = 0.3 with corresponding calculations in
light-front quantization.Comment: 6 pages, LaTeX, 2 figures, uses aipxfm.sty. Talk delivered at the XI
Mexican Workshop on Particles and Fields, Tuxtla Gutierrez, Mexico, November
7-12, 2007; to be published in the proceeding
Neutrino Flavor States and the Quantum Theory of Neutrino Oscillations
The standard theory of neutrino oscillations is reviewed, highlighting the
main assumptions: the definition of the flavor states, the equal-momentum
assumption and the time = distance assumption. It is shown that the standard
flavor states are correct approximations of the states that describe neutrinos
in oscillation experiments. The equal-momentum assumption is shown to be
unnecessary for the derivation of the oscillation probability. The time =
distance assumption derives from the wave-packet character of the propagating
neutrinos. We present a simple quantum-mechanical wave-packet model which
allows us to describe the coherence and localization of neutrino oscillations.Comment: 16 pages; talk presented at the XI Mexican Workshop on Particles and
Fields, 7-12 November 2007, Tuxtla Gutierrez, Chiapas, Mexic
Coherent nu-N scattering and the search for physics beyond the standard model
We focus in future proposals to measure coherent neutrino-nuclei scattering
and we show that such kind of experiments are very sensitive to nonstandard
neutrino interactions with quarks. First in a model independent parametrization
and then we focused in particular models such as leptoquarks and models with
extra neutral gauge bosons and with R-parity breaking interactions. We show
that in all these three different types of new physics it is possible to obtain
competitive bounds to those of future collider experiments. For the particular
case of leptoquarks we found that the expected sensitivity to the coupling and
mass for most of the future experimental setups is quite better than the
current constraints.Comment: 6 pages, 1 Figure, Talk given at 11th Mexican Workshop on Particles
and Fields 2007, Tuxtla Gutierrez, Mexico, 7-12 Nov 200
Constraining a bulk viscous matter-dominated cosmological model using SNe Ia, CMB and LSS
We present and constrain a cosmological model which component is a
pressureless fluid with bulk viscosity as an explanation for the present
accelerated expansion of the universe. We study the particular model of a
constant bulk viscosity coefficient \zeta_m. The possible values of \zeta_m are
constrained using the cosmological tests of SNe Ia Gold 2006 sample, the CMB
shift parameter R from the three-year WMAP observations, the Baryon Acoustic
Oscillation (BAO) peak A from the Sloan Digital Sky Survey (SDSS) and the
Second Law of Thermodynamics (SLT). It was found that this model is in
agreement with the SLT using only the SNe Ia test. However when the model is
submitted to the three cosmological tests together (SNe+CMB+BAO) the results
are: 1.- the model violates the SLT, 2.- predicts a value of H_0 \approx 53 km
sec^{-1} Mpc^{-1} for the Hubble constant, and 3.- we obtain a bad fit to data
with a \chi^2_{min} \approx 400 (\chi^2_{d.o.f.} \approx 2.2). These results
indicate that this model is ruled out by the observations.Comment: 4 pages, 1 figure. Work presented in the XI Mexican Workshop on
Particles and Fields, Tuxtla Gutierrez, Mexico, nov 7-12, 2007. Submitted to
AIP Conference Proceedings of this conferenc
Proton to pion ratio at RHIC from dynamical quark recombination
We propose an scenario to study, from a dynamical point of view, the thermal
recombination of quarks in the midsts of a relativistic heavy-ion collision. We
coin the term dynamical quark recombination to refer to the process of
quark-antiquark and three-quark clustering, to form mesons and baryons,
respectively, as a function of energy density. Using the string-flip model we
show that the probabilities to form such clusters differ. We apply these ideas
to the calculation of the proton and pion spectra in a Bjorken-like scenario
that incorporates the evolution of these probabilities with proper time and
compute the proton to pion ratio, comparing to recent RHIC data at the highest
energy. We show that for a standard choice of parameters, this ratio reaches
one, though the maximum is very sensitive to the initial evolution proper time.Comment: To appear in the proceedings of the XI Mexican Workshop on Particles
and Fields, Tuxtla Gutierrez Chiapas, Mexico, 7-12 Nov. 200
METHOD AND SYSTEM FOR DETECTING A PROCESS OR ACTIVITY USING RECURRENT AND CONVOLUTIONAL 1D NEURAL NETWORKS
Presented herein are techniques that use multiple neural networks and segmentation of the traffic to detect the presence of applications or business processes within a noisy mixture of network traffic. In addition, the techniques presented herein provide a novel way to detect unusual, bad intentioned, and/or malicious activity, which is also a “process”, using recurrent and convolutional neural networks. The learning outcome can potentially identify compromised network infrastructure devices and/or telemetry collectors
What country, university or research institute, performed the best on COVID-19? Bibliometric analysis of scientific literature
In this article, we conduct data mining to discover the countries,
universities and companies, produced or collaborated the most research on
Covid-19 since the pandemic started. We present some interesting findings, but
despite analysing all available records on COVID-19 from the Web of Science
Core Collection, we failed to reach any significant conclusions on how the
world responded to the COVID-19 pandemic. Therefore, we increased our analysis
to include all available data records on pandemics and epidemics from 1900 to
2020. We discover some interesting results on countries, universities and
companies, that produced collaborated most the most in research on pandemic and
epidemics. Then we compared the results with the analysing on COVID-19 data
records. This has created some interesting findings that are explained and
graphically visualised in the article
Design of a Highly Efficient Microinverter
This paper proposes a grid-tied single-phase photovoltaic (PV) microinverter consisting of five-level four-switch (5L-4S) DC-AC converter fed by an isolated fly-back DC-DC converter. The microinverter utilizes a split-coil inductor to produce five levels of pulse width modulation (PWM) compared to the three levels of PWM using conventional four-switch topologies. These implementations reduce losses by up to 39% compared to a conventional topology. The results show that the proposed design improves performance throughout the switching frequency spectra with various loads. The theoretical expectations are validated with simulation and experimental results
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