1,784 research outputs found
A NEW HIGH-INTENSITY ULTRASONIC TECHNOLOGY FOR FOOD DEHYDRATION
12 páginas, 7 figurasAt present, there is a growing interest in the field of dehydration for preserving food. Ultrasonic energy represents a means to obtain dehydration without affecting the food. This paper deals with an experimental study about the use of high-intensity ultrasound for vegetable dehydration by using a new power ultrasound generator and a procedure in which ultrasonic vibrations are applied in direct contact with the product and under a certain static pressure. The drying effect of this new process is compared with that obtained from forced-air drying assisted by air-borne ultrasonic radiation and from a conventional hot-air drying. The results show that by using the new technology and procedure it is possible to reduce dramatically the treatment time and it is relatively easy to reach a final moisture content in the samples less than 1%. In addition, the product qualities are well preserved, the sample rehydration is higher than 70% and, because of the high efficiency of the new ultrasonic system employed, the energy consumption is low. As a consequence of the results a new technology for industrial applications is under development.Peer reviewe
An Algorithm for Matching Perspective Views of 3-D Object by Using Composite Circuits
National Science Foundation / MCS 82-06926Ope
Structural Characterization of Rapid Thermal Oxidized Si\u3csub\u3e1−x−y\u3c/sub\u3eGe\u3csub\u3ex\u3c/sub\u3eC\u3csub\u3ey\u3c/sub\u3e Alloy Films Grown by Rapid Thermal Chemical Vapor Deposition
The structural properties of as-grown and rapid thermal oxidized Si1−x−yGexCy epitaxial layers have been examined using a combination of infrared, x-ray photoelectron, x-ray diffraction, secondary ion mass spectroscopy, and Raman spectroscopy techniques. Carbon incorporation into the Si1−x−yGexCy system can lead to compressive or tensile strain in the film. The structural properties of the oxidized Si1−x−yGexCy film depend on the type of strain (i.e., carbon concentration) of the as-prepared film. For compressive or fully compensated films, the oxidation process drastically reduces the carbon content so that the oxidized films closely resemble to Si1−xGex films. For tensile films, two broad regions, one with carbon content higher and the other lower than that required for full strain compensation, coexist in the oxidized films
R-matrices of U_qOSP(1,2) for highest weight representations of U_qOSP(1,2) for general q and q is an odd root of unity
We obtain the formula for intertwining operator(R-matrix) of quantum
universal enveloping superalgebra U_qOSP(1,2) for U_qOSP(1,2)-Verma modules. By
its restriction we obtain the R-matrix for two semiperiodic(semicyclic), two
spin-j and spin-j and semiperiodic representationsComment: 9 pages, Yerevan preprint 1993, LATE
Observations of the post shock break-out emission of SN 2011dh with XMM-Newton
After the occurrence of the type cIIb SN 2011dh in the nearby spiral galaxy M
51 numerous observations were performed with different telescopes in various
bands ranging from radio to gamma-rays. We analysed the XMM-Newton and Swift
observations taken 3 to 30 days after the SN explosion to study the X-ray
spectrum of SN 2011dh. We extracted spectra from the XMM-Newton observations,
which took place ~7 and 11 days after the SN. In addition, we created
integrated Swift/XRT spectra of 3 to 10 days and 11 to 30 days. The spectra are
well fitted with a power-law spectrum absorbed with Galactic foreground
absorption. In addition, we find a harder spectral component in the first
XMM-Newton spectrum taken at t ~ 7 d. This component is also detected in the
first Swift spectrum of t = 3 - 10 d. While the persistent power-law component
can be explained as inverse Compton emission from radio synchrotron emitting
electrons, the harder component is most likely bremsstrahlung emission from the
shocked stellar wind. Therefore, the harder X-ray emission that fades away
after t ~ 10 d can be interpreted as emission from the shocked circumstellar
wind of SN 2011dh.Comment: Accepted for publication as a Research Note in Astronomy and
Astrophysic
Anisotropic Transport of Quantum Hall Meron-Pair Excitations
Double-layer quantum Hall systems at total filling factor can
exhibit a commensurate-incommensurate phase transition driven by a magnetic
field oriented parallel to the layers. Within the commensurate
phase, the lowest charge excitations are believed to be linearly-confined Meron
pairs, which are energetically favored to align with . In order
to investigate this interesting object, we propose a gated double-layer Hall
bar experiment in which can be rotated with respect to the
direction of a constriction. We demonstrate the strong angle-dependent
transport due to the anisotropic nature of linearly-confined Meron pairs and
discuss how it would be manifested in experiment.Comment: 4 pages, RevTex, 3 postscript figure
Non-perturbative calculations of a global U(1) theory at finite density and temperature
We use an optimised hopping parameter expansion for the free energy (linear
delta expansion) to study the phase transitions at finite temperature and
finite charge density in a global U(1) scalar Higgs sector on the lattice at
large lattice couplings. We are able to plot out phase diagrams in lattice
parameter space and find that the standard second-order phase transition with
temperature at zero chemical potential becomes first order as the chemical
potential increases.Comment: 24 pages, 11 figure
Renal pericytes: regulators of medullary blood flow
Regulation of medullary blood flow (MBF) is essential in maintaining normal kidney function. Blood flow to the medulla is supplied by the descending vasa recta (DVR), which arise from the efferent arterioles of juxtamedullary glomeruli. DVR are composed of a continuous endothelium, intercalated with smooth muscle-like cells called pericytes. Pericytes have been shown to alter the diameter of isolated and in situ DVR in response to vasoactive stimuli that are transmitted via a network of autocrine and paracrine signalling pathways. Vasoactive stimuli can be released by neighbouring tubular epithelial, endothelial, red blood cells and neuronal cells in response to changes in NaCl transport and oxygen tension. The experimentally described sensitivity of pericytes to these stimuli strongly suggests their leading role in the phenomenon of MBF autoregulation. Because the debate on autoregulation of MBF fervently continues, we discuss the evidence favouring a physiological role for pericytes in the regulation of MBF and describe their potential role in tubulo-vascular cross-talk in this region of the kidney. Our review also considers current methods used to explore pericyte activity and function in the renal medulla
Gravitational anomaly and fundamental forces
I present an argument, based on the topology of the universe, why there are
three generations of fermions. The argument implies a preferred gauge group of
SU(5), but with SO(10) representations of the fermions. The breaking pattern
SU(5) to SU(3)xSU(2)xU(1) is preferred over the pattern SU(5) to SU(4)xU(1). On
the basis of the argument one expects an asymmetry in the early universe
microwave data, which might have been detected already.Comment: Contribution to the 2nd School and Workshop on Quantum Gravity and
Quantum Geometry. Corfu, september 13-20 2009. 10 page
An optimized perturbation expansion for a global O(2) theory
We use an optimised perturbation expansion called the linear delta-expansion to study the phase transition in a Higgs sector with a continuous symmetry and large couplings. Our results show how to use this non-perturbative method successfully for such problems. We also show how to simplify the method without losing any flexibility
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