5,338 research outputs found
ATLAS Tile Calorimeter Readout Electronics Upgrade Program for the High Luminosity LHC
The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the most
central region of the ATLAS experiment at LHC. The TileCal readout consists of
about 10000 channels. The ATLAS upgrade program is divided in three phases: The
Phase~0 occurs during 2013-2014, Phase~1 during 2018-1019 and finally Phase~2,
which is foreseen for 2022-2023, whereafter the peak luminosity will reach 5-7
x 10 cms (HL-LHC). The main TileCal upgrade is focused on the
Phase~2 period. The upgrade aims at replacing the majority of the on- and
off-detector electronics so that all calorimeter signals are directly digitized
and sent to the off-detector electronics in the counting room. All new
electronics must be able to cope with the increased radiation levels. An
ambitious upgrade development program is pursued to study different electronics
options. Three options are presently being investigated for the front-end
electronic upgrade. The first option is an improved version of the present
system built using commercial components, the second alternative is based on
the development of a dedicated ASIC (Application Specific Integrated Circuit)
and the third is the development of a new version of the QIE (Charge Integrator
and Encoder) based on the one developed for Fermilab. All three options will
use the same readout and control system using high speed (up to 40 Gb/s) links
for communication and clock synchronization. For the off-detector electronics a
new back-end architecture is being developed. A demonstrator prototype read-out
for a slice of the calorimeter with most of the new electronics, but still
compatible with the present system, is planned to be inserted in ATLAS already
in mid 2014 (at the end of the Phase~0 upgrade).Comment: 6 pages, 6 figures, LISHEP 201
Tile Calorimeter Upgrade Program for the Luminosity Increasing at the LHC
The Tile Calorimeter (TileCal) is the central hadronic calorimeter of the
ATLAS experiment at the Large Hadron Collider (LHC). The LHC is scheduled to
undergo a major upgrade, in 2022, for the High Luminosity LHC (HL-LHC). The
ATLAS upgrade program for high luminosity is split into three phases: Phase-0
occurred during and prepared the LHC for Run 2; Phase-I, foreseen
for 2019, will prepare the LHC for Run 3, whereafter the peak luminosity
reaches cm; finally, Phase-II, which is
foreseen for 2024, will prepare the collider for the HL-LHC operation ( cm). The TileCal main activities for Phase-0 were
the installation of the new low voltage power supplies and the activation of
the TileCal third layer signal for assisting the muon trigger at
(TileMuon Project). In Phase-II, a major upgrade in the
TileCal readout electronics is planned. Except for the photomultipliers tubes
(PMTs), most of the on- and off-detector electronics will be replaced, with the
aim of digitizing all PMT pulses at the front-end level. This work describes
the TileCal upgrade activities, focusing on the TileMuon Project and the new
on-detector electronics.Comment: arXiv admin note: substantial text overlap with arXiv:1305.085
On the Influence of Magnetic Fields on the Structure of Protostellar Jets
We here present the first results of fully three-dimensional (3-D) MHD
simulations of radiative cooling pulsed (time-variable) jets for a set of
parameters which are suitable for protostellar outflows. Considering different
initial magnetic field topologies in approximate with the
thermal gas, i.e., (i) a longitudinal, and (ii) a helical field, both of which
permeating the jet and the ambient medium; and (iii) a purely toroidal field
permeating only the jet, we find that the overall morphology of the pulsed jet
is not very much affected by the presence of the different magnetic field
geometries in comparison to a nonmagnetic calculation. Instead, the magnetic
fields tend to affect essentially the detailed structure and emission
properties behind the shocks at the head and at the pulse-induced internal
knots, particularly for the helical and toroidal geometries. In these cases, we
find, for example, that the emissivity behind the internal knots can
be about three to four times larger than that of the purely hydrodynamical jet.
We also find that some features, like the nose cones that often develop at the
jet head in 2-D calculations involving toroidal magnetic fields, are smoothed
out or absent in the 3-D calculations.Comment: 13 pages, 3 figures, Accepted by ApJ Letters after minor corrections
(for high resolution figures, see http://www.iagusp.usp.br/~adriano/h.tar
Testes de desinfestação para cultivo in vitro de variedades de Helicônia.
A acentuada procura por helicônias, principalmente por parte do mercado externo tem colocado o cultivo desse gênero de plantas em posição de destaque, dentre as atividades desenvolvidas no ramo da floricultura. A pouca oferta de mudas e a inexistência de mudas sadias prejudicam consideravelmente a expansão dessa cultura. A presença de microrganismos endofÃticos, como a Pseudomonas sp., representa um empecilho no desenvolvimento de trabalhos de cultura de tecidos em helicônias.PDF. 124_11
Bananeira de coração branco: inovação para o mercado de ornamentais.
O presente trabalho teve como objetivo selecionar hÃbridos de bananeira ornamental com potencial de uso como plantas para vaso, paisagismo, flor de corte e minifrutos para arranjos florais. Cinquenta e dois hÃbridos oriundos de sete cruzamentos foram avaliados em três ciclos de produção. Para os caracteres quantitativos foram utilizados descritores para caracterÃsticas vegetativas da planta (altura da planta, diâmetro do pseudocaule, número de perfilhos e número de folhas no florescimento); para caracterÃsticas de cacho (comprimento do engaço, diâmetro do engaço, número de pencas por cacho, distância entre pencas, número de dedos por pencas, comprimento do fruto e diâmetro do fruto) e para inflorescência masculina (comprimento do coração e diâmetro do coração)
Caracterização morfoagronômica de diferentes copas de maracujazeiro enxertadas em porta-enxerto de Passiflora gibertii.
Este trabalho teve como objetivo caracterizar morfoagronomicamente diferentes copas de maracujazeiro enxertadas em porta-enxertos de Passiflora gibertii, com vistas à seleção de copas superiores. Foi utilizado um porta-enxerto com 25 copas diferentes, previamente obtidos do trabalho de pesquisa desenvolvido pela equipe de Recursos Genéticos da Embrapa Mandioca e Fruticultura
Effect of glycerol and corn oil on physicochemical properties of polysaccharide films : a comparative study
The aim of this work was to evaluate the influence of glycerol and corn oil on physicochemical properties of polysaccharide-based films. The polysaccharides used were galactomannan from Gleditsia triacanthos and chitosan. Fourier-transform infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis were performed, together with determinations of moisture content, solubility, water vapor permeability and mechanical properties. Structure–properties relationships were established, relating the two polysaccharides’ structures with the way they interact with water, other film’s constituents (glycerol and oil) and the resulting properties. The presence of glycerol and corn oil originated a more hydrophilic structure and a decreased affinity of the film matrix to water, respectively, in both polysaccharides. However, the two polysaccharides presented different behaviors in terms of glass transition temperature, water vapor permeability and elongation-at-break that have been related with the particularities of their structure: while for the galactomannan the specific sorption sites for water are the O–H groups, for chitosan those are O–H and/or NH2 groups.
The present work provides insight regarding the physicochemical properties of polysaccharide-based films and established relationships with polymers’ structure, showing that the two polysaccharides studied here have adequate properties to be used as packaging materials for specific food applications.Miguel A. Cerqueira gratefully acknowledge his fellowship (SFRH/BPD/72753/2010) to the Fundacao para a Ciencia e Tecnologia (FCT, Portugal), and Bartolomeu W. Sousa was recipient of a fellowship from the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES, Brazil)
Exposicao a radiacao solar e genese de solos eutroficos em regioes acidentadas do Brasil sudeste
- …