148 research outputs found
Preon Model and Family Replicated E_6 Unification
Previously we suggested a new preon model of composite quark-leptons and
bosons with the 'flipped' gauge symmetry group. We
assumed that preons are dyons having both hyper-electric and hyper-magnetic
charges, and these preons-dyons are confined by hyper-magnetic
strings which are an supersymmetric non-Abelian flux tubes created
by the condensation of spreons near the Planck scale. In the present paper we
show that the existence of the three types of strings with tensions
producing three (and only three) generations of composite
quark-leptons, also provides three generations of composite gauge bosons
('hyper-gluons') and, as a consequence, predicts the family replicated
unification at the scale GeV. This group of
unification has the possibility of breaking to the group of symmetry: which
undergoes the breakdown to the Standard Model at lower energies. Some
predictive advantages of the family replicated gauge groups of symmetry are
briefly discussed.Comment: This is a contribution to the Proc. of the Seventh International
Conference ''Symmetry in Nonlinear Mathematical Physics'' (June 24-30, 2007,
Kyiv, Ukraine), published in SIGMA (Symmetry, Integrability and Geometry:
Methods and Applications) at http://www.emis.de/journals/SIGMA
Magnetic ordering of EuTe/PbTe multilayers determined by x-ray resonant diffraction
In this work we use resonant x-ray diffraction combined with polarization analysis of the diffracted beam to study the magnetic ordering in EuTe/PbTe multilayers. The presence of satellites at the (1/2 1/2 1/2) magnetic reflection of a 50 /repetition EuTe/PbTe superlattice demonstrated the existence of magnetic correlations among the alternated EuTe layers. The behavior of the satellites intensity as T increases toward the Neel temperature T(N) indicates that these correlations persist nearly up to T(N) and suggests the preferential decrease of the magnetic order parameter of external monolayers of each EuTe layer within the superlattice. (C) 2008 American Institute of Physics.922
Solar Coronal Loops Associated with Small-scale Mixed Polarity Surface Magnetic Fields
How and where are coronal loops rooted in the solar lower atmosphere? The
details of the magnetic environment and its evolution at the footpoints of
coronal loops are crucial to understanding the processes of mass and energy
supply to the solar corona. To address the above question, we use
high-resolution line-of-sight magnetic field data from the Imaging Magnetograph
eXperiment instrument on the SUNRISE balloon-borne observatory and coronal
observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics
Observatory of an emerging active region. We find that the coronal loops are
often rooted at the locations with minor small-scale but persistent
opposite-polarity magnetic elements very close to the larger dominant polarity.
These opposite-polarity small-scale elements continually interact with the
dominant polarity underlying the coronal loop through flux cancellation. At
these locations we detect small inverse Y-shaped jets in chromospheric Ca II H
images obtained from the SUNRISE Filter Imager during the flux cancellation.
Our results indicate that magnetic flux cancellation and reconnection at the
base of coronal loops due to mixed polarity fields might be a crucial feature
for the supply of mass and energy into the corona.Comment: Published in the Astrophysical Journal Supplement Serie
Preliminary Results on Irradiance Measurements from Lyra and Swap
International audienceThe first and preliminary results of the photometry of Large Yield Radiometer (LYRA) and Sun Watcher using Active Pixel system detector and Image Processing (SWAP) onboard PROBA2 are presented in this paper. To study the day-to-day variations of LYRA irradiance, we have compared the LYRA irradiance values (observed Sun as a star) measured in Aluminum filter channel (171 Å-500 Å) with spatially resolved full-disk integrated intensity values measured with SWAP (174 Å) and Ca II K 1 Å index values (ground-based observations from NSO/Sac Peak) for the period from 01 April 2010 to 15 Mar 2011. We found that there is a good correlation between these parameters. This indicates that the spatial resolution of SWAP complements the high temporal resolution of LYRA. Hence SWAP can be considered as an additional radiometric channel. Also the K emission index is the integrated intensity (or flux) over a 1 Å band centered on the K line and is proportional to the total emission from the chromosphere; this comparison clearly explains that the LYRA irradiance variations are due to the various magnetic features, which are contributing significantly. In addition to this we have made an attempt to segregate coronal features from full-disk SWAP images. This will help to understand and determine the actual contribution of the individual coronal feature to LYRA irradiance variations
Assessment of the fate of organic micropollutants in novel wastewater treatment plant configurations through an empirical mechanistic model
Novel wastewater treatment plants (WWTPs) are expected to be less energetically demanding than conventional ones. However, scarce information is available about the fate of organic micropollutants (OMPs) in these novel configurations. Therefore, the objective of this work is to assess the fate of OMPs in three novel WWTP configurations by using a plant-wide simulation that integrates multiple units. The difference among the three configurations is the organic carbon preconcentration technology: chemically enhanced primary treatment (CEPT), high-rate activated sludge (HRAS) combined or not with a rotating belt filter (RBF); followed by a partial-nitritation (PN-AMX) unit. The simulation results show that the three selected novel configurations lead mainly to comparable OMPs removal efficiencies from wastewater, which were similar or lower, depending on the OMP, than those obtained in conventional WWTPs. However, the presence of hydrophobic OMPs in the digested sludge noticeably differs among the three configurations. Whereas the configuration based on sole HRAS to recover organic carbon leads to a lower presence of OMPs in digested sludge than the conventional WWTP, in the other two novel configurations this presence is noticeable higher. In conclusion, novel WWTP configurations do not improve the OMPs elimination from wastewater achieved in conventional ones, but the HRAS-based WWTP configuration leads to the lowest presence in digested sludge so it becomes the most efficient alternativeThe authors would like to thank the EU (ID199) and AEI (PCIN-2015-22) for funding, in the frame of the collaborative international Consortium Pioneer_STP financed under Water Joint Programming Initiative. The authors from Universidade de Santiago de Compostela belong to the Galician Competitive Research Group ED431C 2017/029 and the CRETUS Strategic Partnership (AGRUP2017/01). These programmers are co-funded by FEDER (EU)S
Coherent and sequential photoassisted tunneling through a semiconductor double barrier structure
We have studied the problem of coherent and sequential tunneling through a
double barrier structure, assisted by light considered to be present All over
the structure, i,e emitter, well and collector as in the experimental evidence.
By means of a canonical transformation and in the framework of the time
dependent perturbation theory, we have calculated the transmission coefficient
and the electronic resonant current. Our calculations have been compared with
experimental results turning out to be in good agreement. Also the effect on
the coherent tunneling of a magnetic field parallel to the current in the
presence of light, has been considered.Comment: Revtex3.0, 8figures uuencoded compressed tar-fil
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