336 research outputs found
Efeitos da incorporação da ecosĂlica no desempenho de argamassas produzidas por activação alcalina de metacaulinos
Vol.1Este trabalho aborda os efeitos da incorporação de resĂduos de pĂł de vidro contendo sĂlica amorfa para a produção de argamassas obtidas por ativação alcalina de metacaulinos. SĂŁo utilizadas na preparação das soluçÔes activadoras Ă base de silicato de sĂłdio â ou de potĂĄssio â duas fontes de sĂlica que serĂŁo objeto de comparação: uma proveniente do processo de reciclagem do vidro originĂĄrio do lixo municipal e outra, da produção de ligas metĂĄlicas de ferro-silĂcio da indĂșstria siderĂșrgica. AlĂ©m destas, tambĂ©m sĂŁo adotadas soluçÔes activadoras produzidas a partir de silicatos de sĂłdio e potĂĄssio, obtidos em escala industrial. Este estudo tem por objectivo a avaliação do desempenho em termos de resistĂȘncia e de durabilidade das argamassas analisadas a partir de razĂ”es molares de referĂȘncia. SĂŁo apresentados estudos referentes ao Ăndice de actividade dos materiais analisados cujos resultados promovem a competitividade da sĂlica de vidro verde moĂdo, nomeada ecosĂlica, em termos tĂ©cnicos e econĂŽmicos. Neste estudo sobre a produção de argamassas geopolĂmeras com adição de pĂł de vidro sĂŁo discutidas as condiçÔes de preparo, cura, trabalhabilidade, redução do custo de aquisição dos materiais e a eficiĂȘncia energĂ©tica frente Ă s alternativas propostas
Characterization of parameters to predict the structural behaviour of geopolymeric mortar plates strengthened with carbon fiber reinforced polymer
This study includes the identification of parameters for the characterization of the structural behavior of thin plates composed of geopolymer mortars structured with bi-directional carbon fiber mesh. Initially, facade projects, designed by offices in SĂÂŁo Paulo using the concepts of sustainable architecture, promoting the use of geopolymeric materials are presented. Then shows the composition of the geopolymer mortar used in this study and the characterization of their mechanical properties. As part of the experimental program, this study evaluates the plate bending behavior and the effect of pull-out test and push-off test of the metallic inserts. It has used the advanced features of ATENA computational mechanics program, which correspond to the state of the art in Finite Element Modeling of reinforced concrete structures, which allow the calibration of the mathematical model based on information from the experimental program. The numerical results showed satisfactory adhesion with the experimental results. It also has emphasized the importance of validation of these results on the determination of loads collapse of structural elements, as is reflected positively in the field of Structural Engineering in the face of increasing advancement of surface modeling programs and technological innovations in according to sustainability criteria for constructions materials.(undefined
Bose-Einstein correlations of same-sign charged pions in the forward region in pp collisions at âs=7 TeV
Bose-Einstein correlations of same-sign charged pions, produced in protonproton collisions at a 7 TeV centre-of-mass energy, are studied using a data sample collected
by the LHCb experiment. The signature for Bose-Einstein correlations is observed in the
form of an enhancement of pairs of like-sign charged pions with small four-momentum
difference squared. The charged-particle multiplicity dependence of the Bose-Einstein correlation parameters describing the correlation strength and the size of the emitting source
is investigated, determining both the correlation radius and the chaoticity parameter. The
measured correlation radius is found to increase as a function of increasing charged-particle
multiplicity, while the chaoticity parameter is seen to decreas
Measurement of the inelastic pp cross-section at a centre-of-mass energy of 13TeV
The cross-section for inelastic proton-proton collisions at a centre-of-mass energy of 13TeV is measured with the LHCb detector. The fiducial cross-section for inelastic interactions producing at least one prompt long-lived charged particle with momentum p > 2 GeV/c in the pseudorapidity range 2 < η < 5 is determined to be Ï acc = 62:2 ± 0:2 ± 2:5mb. The first uncertainty is the intrinsic systematic uncertainty of the measurement, the second is due to the uncertainty on the integrated luminosity. The statistical uncertainty is negligible. Extrapolation to full phase space yields the total inelastic proton-proton cross-section Ï inel = 75:4 ± 3:0 ± 4:5mb, where the first uncertainty is experimental and the second due to the extrapolation. An updated value of the inelastic cross-section at a centre-of-mass energy of 7TeV is also reported
Measurement of branching fractions of charmless four-body Î<sub>b</sub> <sup>0</sup> and Î<sub>b</sub> <sup>0</sup> decays
A search for charmless four-body decays of Îb 0 and Îb 0 baryons with a proton and three charged mesons (either kaons or pions) in the final state is performed. The data sample used was recorded in 2011 and 2012 with the LHCb experiment and corresponds to an integrated luminosity of 3 fbâ1. Six decay modes are observed, among which Îb 0 â pKâÏ+Ïâ,Îb 0 â pKâK+Kâ,Îb 0 â pKâÏ+Ïâ and Îb 0 â pKâÏ+Kâ are established for the first time. Their branching fractions (including the ratio of hadronisation fractions in the case of the Îb 0 baryon) are determined relative to the Îb 0 â Îc +Ïâ decay.[Figure not available: see fulltext.].</p
Observation of B(s)0âJ/ÏppÂŻ decays and precision measurements of the B(s)0 masses
The first observation of the decays
B
0
(
s
)
â
J
/
Ï
p
ÂŻ
p
is reported, using proton-proton collision data corresponding to an integrated luminosity of
5.2
â
â
fb
â
1
, collected with the LHCb detector. These decays are suppressed due to limited available phase space, as well as due to Okubo-Zweig-Iizuka or Cabibbo suppression. The measured branching fractions are
B
(
B
0
â
J
/
Ï
p
ÂŻ
p
)
=
[
4.51
±
0.40
(
stat
)
±
0.44
(
syst
)
]
Ă
10
â
7
,
B
(
B
0
s
â
J
/
Ï
p
ÂŻ
p
)
=
[
3.58
±
0.19
(
stat
)
±
0.39
(
syst
)
]
Ă
10
â
6
. For the
B
0
s
meson, the result is much higher than the expected value of
O
(
10
â
9
)
. The small available phase space in these decays also allows for the most precise single measurement of both the
B
0
mass as
5279.74
±
0.30
(
stat
)
±
0.10
(
syst
)
â
â
MeV
and the
B
0
s
mass as
5366.85
±
0.19
(
stat
)
±
0.13
(
syst
)
â
â
MeV
Observation of the decay Î <sub>b</sub> <sup>0</sup> âââÏ(2S)pÏ<sup>â</sup>
International audienceThe Cabibbo-suppressed decay Î âââÏ(2S)pÏ is observed for the first time using a data sample collected by the LHCb experiment in proton-proton collisions corresponding to 1.0, 2.0 and 1.9 fb of integrated luminosity at centre-of-mass energies of 7, 8 and 13 TeV, respectively. The Ï(2S) mesons are reconstructed in the ΌΌ final state. The branching fraction with respect to that of the Î âââÏ(2S)pK decay mode is measured to b
Measurement of the branching fraction and CP asymmetry in B plus . J/.. plus decays
The branching fraction and direct asymmetry of the decay
are measured using proton-proton collision
data collected with the LHCb detector at centre-of-mass energies of 7 and 8
TeV, corresponding to a total integrated luminosity of 3\mbox{fb}^{-1}. The
following results are obtained: \begin{align} \mathcal{B}(B^{+}\rightarrow
J/\psi \rho^{+}) &= (3.81 ^{+0.25}_{-0.24} \pm 0.35) \times 10^{-5}, \nonumber
\\ \mathcal{A}^{C\!P} (B^{+}\rightarrow J/\psi \rho^{+}) &=
-0.045^{+0.056}_{-0.057} \pm 0.008, \nonumber \end{align} where the first
uncertainties are statistical and the second systematic. Both measurements are
the most precise to date.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2018-036.htm
First observation of the rare purely baryonic decay B0 â ppÂŻ
The first observation of the decay of a
B
0
meson to a purely baryonic final state,
B
0
â
p
ÂŻ
p
, is reported. The proton-proton collision data sample used was collected with the LHCb experiment at center-of-mass energies of 7 and 8 TeV and corresponds to an integrated luminosity of
3.0
â
â
fb
â
1
. The branching fraction is determined to be
B
(
B
0
â
p
ÂŻ
p
)
=
(
1.25
±
0.27
±
0.18
)
Ă
10
â
8
, where the first uncertainty is statistical and the second systematic. The decay mode
B
0
â
p
ÂŻ
p
is the rarest decay of the
B
0
meson observed to date. The decay
B
0
s
â
p
ÂŻ
p
is also investigated. No signal is seen and the upper limit
B
(
B
0
s
â
p
ÂŻ
p
)
<
1.5
Ă
10
â
8
at 90% confidence level is set on the branching fraction
Prompt and nonprompt J/Ï production and nuclear modification in pPb collisions at s<sub>NN</sub>=8.16 TeV
The production of J/Ï mesons is studied in proton-lead collisions at the centre-of-mass energy per nucleon pair sNN=8.16 TeV with the LHCb detector at the LHC. The double differential cross-sections of prompt and nonprompt J/Ï production are measured as a function of the J/Ï transverse momentum and rapidity in the nucleonânucleon centre-of-mass frame. Forward-to-backward ratios and nuclear modification factors are determined. The results are compared with theoretical calculations based on collinear factorisation using nuclear parton distribution functions, on the colour glass condensate or on coherent energy loss models.</p
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