7,882 research outputs found
Thermal performance of a solar hybrid dryer for Conilon coffee (Coffea canephora)
The study was aimed at design and development of an energy efficient hybrid solar
dryer suitable for drying of organic Conilon coffee placed in the town of SeropĂŠdica, Rio de
Janeiro, Brazil. The energy efficiency and the drying efficiency were the evaluation criteria for
thermal performance of the hybrid solar dryer during the coffee drying. Temperature and relative
humidity (RH) of the drying and ambient air, solar radiation intensity and coffee weight loss were
monitored during the drying process. The process occurred over six consecutive days; the drying
time was from 07:00 to 17:00 h, totalling 120 h of operation with an intermittent period (at night)
of 14 h. During intermittence, the exhaust system kept off and solar collector and drying chamber
sealed. The effective drying period took 60 h, with temperature and RH, respectively, of 38.3 °C
and 60.6% outlet of the solar collector, 32.7 °C and 72.2% outlet drying chamber and 27.8 °C
and 74.5% ambient air. The maximum temperature in the solar collector and drying chamber
reached 54 and 47.7 °C, respectively, with an ambient air temperature of 32 °C at 12:00 h. These
values showing temperature increase 22.2 °C in solar collector and 10 ºC drying chamber. The
mean variation for the reduction in RH between the drying air inside the solar collector and the
ambient air was 28%, while in the chamber obtained in a range of 10.5% at 13:00 h. The solar
collector and dryer chamber efficiency were 29.1 and 40.8%, respectively, while the overall dryer
efficiency 39.7%
The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: tomographic BAO analysis of DR12 combined sample in configuration space
We perform a tomographic baryon acoustic oscillations analysis using the
two-point galaxy correlation function measured from the combined sample of BOSS
DR12, which covers the redshift range of . Splitting the sample
into multiple overlapping redshift slices to extract the redshift information
of galaxy clustering, we obtain a measurement of and at
nine effective redshifts with the full covariance matrix calibrated using
MultiDark-Patchy mock catalogues. Using the reconstructed galaxy catalogues, we
obtain the precision of for and for
. To quantify the gain from the tomographic information, we compare
the constraints on the cosmological parameters using our 9-bin BAO
measurements, the consensus 3-bin BAO and RSD measurements at three effective
redshifts in \citet{Alam2016}, and the non-tomographic (1-bin) BAO measurement
at a single effective redshift. Comparing the 9-bin with 1-bin constraint
result, it can improve the dark energy Figure of Merit by a factor of 1.24 for
the Chevallier-Polarski-Linder parametrisation for equation of state parameter
. The errors of and from 9-bin constraints are slightly
improved when compared to the 3-bin constraint result.Comment: 14 pages, 21 figures, 7 Tables. Submitted to MNRA
Manipulating spatial qudit states with programmable optical devices
The study of how to generate high-dimensional quantum states (qudits) is
justified by the advantages that they can bring for the field of quantum
information. However, to have some real practical potential for quantum
communication, these states must be also of simple manipulation. Spatial qudits
states, which are generated by engineering the transverse momentum of the
parametric down-converted photons, have been until now considered of hard
manipulation. Nevertheless, we show in this work a simple technique for
modifying these states. This technique is based on the use of programmable
diffractive optical devices, that can act as spatial light modulators, to
define the Hilbert space of these photons instead of pre-fabricated
multi-slits
Genetic diversity analysis of common beans based on molecular markers
A core collection of the common bean (Phaseolus vulgaris L.), representing genetic diversity in the entire Mexican holding, is kept at the INIFAP (Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias, Mexico) Germplasm Bank. After evaluation, the genetic structure of this collection (200 accessions) was compared with that of landraces from the states of Oaxaca, Chiapas and Veracruz (10 genotypes from each), as well as a further 10 cultivars, by means of four amplified fragment length polymorphisms (AFLP) +3/+3 primer combinations and seven simple sequence repeats (SSR) loci, in order to define genetic diversity, variability and mutual relationships. Data underwent cluster (UPGMA) and molecular variance (AMOVA) analyses. AFLP analysis produced 530 bands (88.5% polymorphic) while SSR primers amplified 174 alleles, all polymorphic (8.2 alleles per locus). AFLP indicated that the highest genetic diversity was to be found in ten commercial-seed classes from two major groups of accessions from Central Mexico and Chiapas, which seems to be an important center of diversity in the south. A third group included genotypes from Nueva Granada, Mesoamerica, Jalisco and Durango races. Here, SSR analysis indicated a reduced number of shared haplotypes among accessions, whereas the highest genetic components of AMOVA variation were found within accessions. Genetic diversity observed in the common-bean core collection represents an important sample of the total Phaseolus genetic variability at the main Germplasm Bank of INIFAP. Molecular marker strategies could contribute to a better understanding of the genetic structure of the core collection as well as to its improvement and validation
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A Search for Dark Higgs Bosons
Recent astrophysical and terrestrial experiments have motivated the proposal
of a dark sector with GeV-scale gauge boson force carriers and new Higgs
bosons. We present a search for a dark Higgs boson using 516 fb-1 of data
collected with the BABAR detector. We do not observe a significant signal and
we set 90% confidence level upper limits on the product of the Standard
Model-dark sector mixing angle and the dark sector coupling constant.Comment: 7 pages, 5 postscript figures, published version with improved plots
for b/w printin
Charge separation relative to the reaction plane in Pb-Pb collisions at TeV
Measurements of charge dependent azimuthal correlations with the ALICE
detector at the LHC are reported for Pb-Pb collisions at TeV. Two- and three-particle charge-dependent azimuthal correlations in
the pseudo-rapidity range are presented as a function of the
collision centrality, particle separation in pseudo-rapidity, and transverse
momentum. A clear signal compatible with a charge-dependent separation relative
to the reaction plane is observed, which shows little or no collision energy
dependence when compared to measurements at RHIC energies. This provides a new
insight for understanding the nature of the charge dependent azimuthal
correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE
In this small note we are concerned with the solution of Forward-Backward
Stochastic Differential Equations (FBSDE) with drivers that grow quadratically
in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem
is a comparison result that allows comparing componentwise the signs of the
control processes of two different qgFBSDE. As a byproduct one obtains
conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio
Transverse sphericity of primary charged particles in minimum bias proton-proton collisions at , 2.76 and 7 TeV
Measurements of the sphericity of primary charged particles in minimum bias
proton--proton collisions at , 2.76 and 7 TeV with the ALICE
detector at the LHC are presented. The observable is linearized to be collinear
safe and is measured in the plane perpendicular to the beam direction using
primary charged tracks with GeV/c in . The
mean sphericity as a function of the charged particle multiplicity at
mid-rapidity () is reported for events with different
scales ("soft" and "hard") defined by the transverse momentum of the leading
particle. In addition, the mean charged particle transverse momentum versus
multiplicity is presented for the different event classes, and the sphericity
distributions in bins of multiplicity are presented. The data are compared with
calculations of standard Monte Carlo event generators. The transverse
sphericity is found to grow with multiplicity at all collision energies, with a
steeper rise at low , whereas the event generators show the
opposite tendency. The combined study of the sphericity and the mean with multiplicity indicates that most of the tested event generators
produce events with higher multiplicity by generating more back-to-back jets
resulting in decreased sphericity (and isotropy). The PYTHIA6 generator with
tune PERUGIA-2011 exhibits a noticeable improvement in describing the data,
compared to the other tested generators.Comment: 21 pages, 9 captioned figures, 3 tables, authors from page 16,
published version, figures from
http://aliceinfo.cern.ch/ArtSubmission/node/308
Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV
The t t-bar production cross section (sigma[t t-bar]) is measured in
proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS
experiment, corresponding to an integrated luminosity of 2.3 inverse
femtobarns. The measurement is performed in events with two leptons (electrons
or muons) in the final state, at least two jets identified as jets originating
from b quarks, and the presence of an imbalance in transverse momentum. The
measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/-
2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction
of the standard model.Comment: Replaced with published version. Included journal reference and DO
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
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