15,548 research outputs found
A Measurement of Secondary Cosmic Microwave Background Anisotropies with Two Years of South Pole Telescope Observations
We present the first three-frequency South Pole Telescope (SPT) cosmic microwave background (CMB) power spectra. The band powers presented here cover angular scales 2000 < ℓ < 9400 in frequency bands centered at 95, 150, and 220 GHz. At these frequencies and angular scales, a combination of the primary CMB anisotropy, thermal and kinetic Sunyaev-Zel'dovich (SZ) effects, radio galaxies, and cosmic infrared background (CIB) contributes to the signal. We combine Planck/HFI and SPT data at 220 GHz to constrain the amplitude and shape of the CIB power spectrum and find strong evidence for nonlinear clustering. We explore the SZ results using a variety of cosmological models for the CMB and CIB anisotropies and find them to be robust with one exception: allowing for spatial correlations between the thermal SZ effect and CIB significantly degrades the SZ constraints. Neglecting this potential correlation, we find the thermal SZ power at 150 GHz and ℓ = 3000 to be 3.65 ± 0.69 μK^2, and set an upper limit on the kinetic SZ power to be less than 2.8 μK^2 at 95% confidence. When a correlation between the thermal SZ and CIB is allowed, we constrain a linear combination of thermal and kinetic SZ power: D^(tSZ)_(3000) + 0.5D^(kSZ)_(3000) = 4.60 ± 0.63 μK^2, consistent with earlier measurements. We use the measured thermal SZ power and an analytic, thermal SZ model calibrated with simulations to determine σ_8 = 0.807 ± 0.016. Modeling uncertainties involving the astrophysics of the intracluster medium rather than the statistical uncertainty in the measured band powers are the dominant source of uncertainty on σ_8. We also place an upper limit on the kinetic SZ power produced by patchy reionization; a companion paper uses these limits to constrain the reionization history of the universe
Local superconducting density of states of ErNi2B2C
We present local tunnelling microscopy and spectroscopy measurements at low
temperatures in single crystalline samples of the magnetic superconductor
ErNi2B2C. The electronic local density of states shows a striking departure
from s-wave BCS theory with a finite value at the Fermi level, which amounts to
half of the normal phase density of states.Comment: 9 pages, 3 figure
Utilização de lodo de esgoto como fonte de fósforo na cultura de soja.
bitstream/CNPMA/5851/1/circular_6.pd
Mathematical modeling of handmade recycled paper drying kinetics and sorption isotherms
The objective of this work is to analyze and compare the natural and forced convective drying of handmade recycled paper. Drying of recycled cellulose pulp was carried out under laboratory environment conditions and in a convective dryer with forced air circulation and controlled conditions of air temperature and velocity. The tests were conducted following a two-factor central composed factorial design of experiments, with six runs at the central point. The drying results were analyzed and fitted to mathematical models of Fick, Henderson and Pabis (Fick s modified equation), Page and He (considering the nonlinear Fick effect). The model of Page represented best the experimental data and the one of Henderson and Pabis resulted in an adequate fit for the paper drying kinetics. Sorption isotherms were determined for the dried paper and the models of GAB (Guggenheim-Anderson-de Boer) and GDW (Generalised D Arcy and Watt) resulted in excellent fits of the experimental data. The water sorption mechanism was suggested by the analysis of the calculated parameters of the GDW model.299312Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP
Classification of algebras with minimal quadratic growth of identities
The main goal of this paper is to prove that the five algebraswhich were used in [3] to classify (up to PI-equivalence) thealgebras whose sequence of codimensions is bounded by a linear functiongenerate the only five minimal varieties of quadratic growth
Central polynomials for matrix algebras over the Grassmann algebra
In this work, we describe a method to construct central polynomials for F-algebras where F is a field of characteristic zero. The main application deals with the T-prime algebras Mn(E), where E is the infinite- dimensional Grassmann algebra over F, which play a fundamental role in the theory of PI-algebras. The method is based on the explicit decomposition of the group algebra FSn. AMS Classification 2000: Primary 16R10, Secondary 16W50, 15A75. Keywords: Polynomial identities, central polynomials, Grassmann algebra.Â
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