1,051 research outputs found
Hadron multiplicity induced by top quark decays at the LHC
The average charged hadron multiplicities induced by top quark decays are
calculated in pQCD at LHC energies. Different modes of top production are
considered. Proposed measurements can be used as an additional test of pQCD
calculations independent on a fragmentation model.Comment: 12 pages, 12 figures, to be published elsewher
Geographical stratification by socio-economic status: methodology from a household survey with elderly people in S. Paulo, Brazil
The intrinsic features of the specific heat at half-filled Landau levels of two-dimensional electron systems
The specific heat capacity of a two-dimensional electron gas is derived for
two types of the density of states, namely, the Dirac delta function spectrum
and that based on a Gaussian function. For the first time, a closed form
expression of the specific heat for each case is obtained at half-filling. When
the chemical potential is temperature-independent, the temperature is
calculated at which the specific heat is a maximum. Here the effects of the
broadening of the Landau levels are distinguished from those of the different
filling factors. In general, the results derived herein hold for any
thermodynamic system having similar resonant states.Comment: 11 pages, 1 figure, to appear in J Low Temp Phys (2010
A cost-effective microfluidic device for determination of biodiesel content in diesel blends
The increasing production and extensive use of biodiesel in the latest years call for the development of fast and cost-effective procedures for point-of-care analysis. One of the main quality parameters is the biodiesel content in diesel blends, which needs to conform to regional legislations. In this work, a microfluidic device exploiting chemical derivatization of alkyl esters and detection by smartphone-based digital-image colorimetry was developed. It was designed to ensure proper experimental conditions for chemical derivatization, including re- agent release, and photometric measurements. Analytes reacted with alkaline hydroxylamine yielding the cor- responding alkyl hydroxamates, measured as colored Fe(III) complexes. Analytical response was based on the measurement of the G (green) channel from RGB color system. By taking methyl linoleate as a model compound, a linear response was obtained from 0.1% to 0.6%(v/v) (Analytical signal = 69.6 +2.1 C, r = 0.999), coefficient of variation (n = 10) of 4.0% and limit of detection (99.7% confidence) of 0.04%(v/v). Procedure consumes 1.2 ”L of sample, 230 ”g of hydroxylamine, 480 ”g of NaOH, 14 ”g of Fe(III) and equivalent to 1.2 ”L of 69%(v/v) HNO3. Accurate results were achieved in relation to the MIR reference method, with agreement at the 95% confidence levelThe authors gratefully acknowledge the financial support from FundaçËao de Amparo `a Pesquisa do Estado de SËao Paulo FAPESP (proc. 2021/12242â5 and 2018/07687â5). and the support from the Spanish âMinisterio de EconomĂa y Competitividadâ (Project PID2019â103938RB- I00) and Junta de AndalucĂa (Projects B-FQM-243-UGR18 and P18-RT- 2961)
From Coherent Modes to Turbulence and Granulation of Trapped Gases
The process of exciting the gas of trapped bosons from an equilibrium initial
state to strongly nonequilibrium states is described as a procedure of symmetry
restoration caused by external perturbations. Initially, the trapped gas is
cooled down to such low temperatures, when practically all atoms are in
Bose-Einstein condensed state, which implies the broken global gauge symmetry.
Excitations are realized either by imposing external alternating fields,
modulating the trapping potential and shaking the cloud of trapped atoms, or it
can be done by varying atomic interactions by means of Feshbach resonance
techniques. Gradually increasing the amount of energy pumped into the system,
which is realized either by strengthening the modulation amplitude or by
increasing the excitation time, produces a series of nonequilibrium states,
with the growing fraction of atoms for which the gauge symmetry is restored. In
this way, the initial equilibrium system, with the broken gauge symmetry and
all atoms condensed, can be excited to the state, where all atoms are in the
normal state, with completely restored gauge symmetry. In this process, the
system, starting from the regular superfluid state, passes through the states
of vortex superfluid, turbulent superfluid, heterophase granular fluid, to the
state of normal chaotic fluid in turbulent regime. Both theoretical and
experimental studies are presented.Comment: Latex file, 25 pages, 4 figure
Demanda por doenças crĂŽnico-degenerativas entre adultos matriculados em uma unidade bĂĄsica de saĂșde em SĂŁo Carlos - SP
Chemical composition of essential oil extracted from leaves of Campomanesia adamantium subjected to different hydrodistillation times
InterferĂȘncia da redução no volume de aplicação sobre o controle da mancha preta (Guignardia citricarpa Kiely) em frutos de laranja 'ValĂȘncia'
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