958 research outputs found
Supersolid Helium at High Pressure
We have measured the pressure dependence of the supersolid fraction by a
torsional oscillator technique. Superflow is found from 25.6 bar up to 136.9
bar. The supersolid fraction in the low temperature limit increases from 0.6 %
at 25.6 bar near the melting boundary up to a maximum of 1.5% near 55 bar
before showing a monotonic decrease with pressure extrapolating to zero near
170 bar.Comment: 4 pages, 4 figure
Dielectronic Resonance Method for Measuring Isotope Shifts
Longstanding problems in the comparison of very accurate hyperfine-shift
measurements to theory were partly overcome by precise measurements on
few-electron highly-charged ions. Still the agreement between theory and
experiment is unsatisfactory. In this paper, we present a radically new way of
precisely measuring hyperfine shifts, and demonstrate its effectiveness in the
case of the hyperfine shift of and in
. It is based on the precise detection of dielectronic
resonances that occur in electron-ion recombination at very low energy. This
allows us to determine the hyperfine constant to around 0.6 meV accuracy which
is on the order of 10%
Optimization of camu-camu pulp concentration added in gummy candies / Otimização da concentração de polpa de camu-camu adicionada embalas de goma
The camu-camu (Myrciaria dúbia McVaugh), a superfruit from Amazon region, is considered the richest source of vitamin C, being also rich in bioactive compounds such as polyphenols and carotenoids. Several studies have been published on health properties of camu-camu and derived products.This work aimed to optimize the concentration of camu-camu pulp added in the formulation of gummy candies elaborated using both gelling agent pectin and gelatin to replace flavouring and colouring and to enrich the candies with the Amazonian superfuit biocompounds. The ingredientes used for pectin candy elaboration were pectin (GENU 121 Slow Set), sugar, glucose syrup, camu-camu pulp and water and for gelatin candy elaboration were gelatin 240 bloom, xylitol, maltitol syrup, camu-camu pulp, water, citric acid and capol. To optimize the concentration of the different ingredients used in the formulations of both pectin and gelatin candies, a Rotational Central Composite Design (RCCD) was used with the performance of a complete factorial 23, including 6 centered points and three repetitions at the central point, totalizing 17 tests.Considering the experimental conditions employed in carrying out this work, it can be said that the objective initially proposed was successfully achieved and it was possible to optimize the concentration of ingredients in the formulation of both pectin and gelatin candies, with addition of 20.5% and 15% of camu-camu pulp in the candies formulations, respectively. The candies developed can be considered innovative products, free of artificial flavorings and dyes due to the use of camu-camu pulp in its formulation.
Xcompact3D: An open-source framework for solving turbulence problems on a Cartesian mesh
Xcompact3D is a Fortran 90–95 open-source framework designed for fast and accurate simulations of turbulent flows, targeting CPU-based supercomputers. It is an evolution of the flow solver Incompact3D which was initially designed in France in the mid-90’s for serial processors to solve the incompressible Navier–Stokes equations. Incompact3D was then ported to parallel High Performance Computing (HPC) systems in the early 2010’s. Very recently the capabilities of Incompact3D have been extended so that it can now tackle more flow regimes (from incompressible flows to compressible flows at low Mach numbers), resulting in the design of a new user-friendly framework called Xcompact3D. The present manuscript presents an overview of Xcompact3D with a particular focus on its functionalities, its ready-to-run simulations and a few case studies to demonstrate its impact
Preparation and verification of tensor network states
We consider a family of tensor network states defined on regular lattices that come with a natural definition of an adiabatic path to prepare them. This family comprises relevant classes of states, such as injective matrix product and projected entangled-pair states, and some corresponding to classical spin models. We show how uniform lower bounds to the gap of the parent Hamiltonian along the adiabatic trajectory can be efficiently computed using semidefinite programming. This allows one to check whether the adiabatic preparation can be performed efficiently with a scalable effort. We also derive a set of observables whose expectation values can be easily determined and that form a complete set, in the sense that they uniquely characterize the state. We identify a subset of those observables which can be efficiently computed if one has access to the quantum state and local measurements, and analyze how they can be used in verification procedures
Efeito do estiolamento parcial e do ácido indolbutírico (IBA) no enraizamento de estacas de ramos de goiabeira serrana (Feijoa sellowiana, Berg)
With the aim of verifying branching and indolbutyric acid (IBA) effects on the rootling of cuttings of feijoa, this work was carried out considering three different dates of blanching, in greenhouse. The branching of various plants with uniform size and age was performed prior to branch trimming. Branch cuttings obtained at three blanching times (Zero, 40 and 60 days); treated with Zero; 5000; 7000; 9000 and 11000 ppm of power IBA, were used. The number of rooted cuttings was evaluated in order to calculate percent rooting. The results showed that the blanching was effective in rooting and the best time was variable according to the date of branch blanching; the IBA showed negative effect on rooting.Com o objetivo de verificar o efeito do estiolamento parcial dos ramos e do ácido indolbutírico (IBA), no enraizamento de estacas de Feijoa sellowiana, conduziu-se este trabalho de enraizamento em três épocas de estiolamento, utilizando-se câmara de nebulização. Antes das estacas serem retiradas efetuou-se o estiolamento dos ramos de diversas plantas, com uniformidade de tamanho e idade. Foram utilizadas estacas de ramos em três intervalos de estiolamento (zero, 40 e 60 dias), tratadas com Zero; 5000; 7000; 9000 e 11000 ppm de IBA, na formulação de pó. Foi avaliado o número de estacas enraizadas, determinando-se a percentagem de enraizamento. Os resultados mostraram que estiolamento parcial foi efetivo para o enraizamento, sendo que o melhor intervalo foi variável conforme a época de estiolamento dos ramos e o IBA teve efeito negativo sobre o enraizamento
Projection, Spatial Correlations, and Anisotropies in a Large and Complete Sample of Abell Clusters
An analysis of R >= 1 Abell clusters is presented for samples containing
recent redshifts from the MX Northern Abell Cluster Survey. The newly obtained
redshifts from the MX Survey as well as those from the ESO Nearby Abell Cluster
Survey (ENACS) provide the necessary data for the largest magnitude-limited
correlation analysis of rich clusters in the entire sky (excluding the galactic
plane) to date. We find 19.4 <= r_0 <= 23.3 h^-1Mpc, -1.92 <= gamma <= -1.83
for four different subsets of Abell/ACO clusters, including a large sample
(N=104) of cD clusters. We have used this dataset to look for line-of-sight
anisotropies within the Abell/ACO catalogs. We show that the strong
anisotropies present in previously studied Abell cluster datasets are not
present in our R >= 1 samples. There are, however, indications of residual
anisotropies which we show are the result of two elongated superclusters, Ursa
Majoris and Corona Borealis, whose axes lie near the line-of-sight. After
rotating these superclusters so that their semi-major axes are prependicular to
the line-of-sight, we find no anisotropies as indicated by the correlation
function. The amplitude and slope of the two-point correlation function remain
the same before and after these rotations. We also remove a subset of R = 1
Abell/ACO clusters that show sizable foreground/background galaxy contamination
and again find no change in the amplitude or slope of the correlation function.
We conclude that the correlation length of R >= 1 Abell clusters is not
artificially enhanced by line-of-sight anisotropies.Comment: 37 pages, 8 figures, AASTeX Accepted for publication in Ap
Charge- And Angle-correlated Inelasticities In Collisions Of Bare Fast Carbon Ions With Neon
We have studied the detailed energy balance in collisions of 10-MeV C6+ ions with Ne. In these collisions, the Ne is multiply ionized and the C ion may emerge as either C6+ or C5+. Projectile energy loss and scattering angle for a given carbon-ion charge state were determined in a high-resolution magnetic spectrograph and were measured in coincidence with the formation of a given Ne recoil-ion charge state. The amount of energy transferred to the continuum electrons exceeds, by far, the sum of the values of the ionization potentials. © 1988 The American Physical Society
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