225 research outputs found
Enzymes action on wheat-soy dough properties and bread quality
High levels of soy flour added to wheat bread produce negative effects on gluten network formation, dough properties, and on bread final quality. The objective of this study was to assess the influence of three enzymes, transglutaminase (TG), glucose oxidase (GOX), and endoxylanase (XYL), on dough properties and final quality of high-protein breads. The addition of TG and GOX increased the mixing stability and maximum resistance of dough, decreased its extensibility, and produced stronger and more consistent dough samples. XYL incorporation produced opposite results. XYL addition and the lowest GOX dose increased bread volume significantly and decreased initial crumb firmness, while high doses of TG (0. 3%) produced detrimental effects on bread volume and crumb firmness. In conclusion, XYL and GOX 0. 001% addition improved the final quality of soy-fortified breads, but XYL was the best additive to improve dough properties, bread volume, and quality. © 2010 Springer Science + Business Media, LLC.Fil: Roccia Ruffinengo, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Ribotta, Pablo Daniel. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Ferrero, Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Pérez, Gabriela T.. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: León, Alberto E.. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentin
Level density of a Fermi gas: average growth and fluctuations
We compute the level density of a two--component Fermi gas as a function of
the number of particles, angular momentum and excitation energy. The result
includes smooth low--energy corrections to the leading Bethe term (connected to
a generalization of the partition problem and Hardy--Ramanujan formula) plus
oscillatory corrections that describe shell effects. When applied to nuclear
level densities, the theory provides a unified formulation valid from
low--lying states up to levels entering the continuum. The comparison with
experimental data from neutron resonances gives excellent results.Comment: 4 pages, 1 figur
Computational Aeroelasticity of Flying Robots with Flexible Wings
A computational co‐simulation framework for flying robots with flexible wings is presented. The authors combine a nonlinear aerodynamic model based on an extended version of the unsteady vortex‐lattice method with a nonlinear structural model based on a segregated formulation of Lagrange’s equations obtained with the Floating Frame of Reference formalism. The structural model construction allows for hybrid combinations of different models typically used with multibody systems such as models based on rigid‐body dynamics, assumed‐modes techniques, and finite‐element methods. The aerodynamic model includes a simulation of leading‐edge separation for large angles of attack. The governing differential‐algebraic equations are solved simultaneously and interactively to obtain the structural response and the flow in the time domain. The integration is based on the fourth‐order predictor‐corrector method of Hamming with a procedure to stabilize the iteration. The findings are found to capture known nonlinear behavior of flapping-wing systems. The developed framework should be relevant for conducting aeroelastic studies on a wide variety of air vehicle systems
Precision measurements of the Co -asymmetry parameter in search for tensor currents in weak interactions
The -asymmetry parameter for the Gamow-Teller decay of
Co was measured by polarizing the radioactive nuclei with the brute
force low-temperature nuclear-orientation method. The Co activity was
cooled down to milliKelvin temperatures in a He-He dilution
refrigerator in an external 13 T magnetic field. The particles were
observed by a 500 thick Si PIN diode operating at a temperature of
about 10 K in a magnetic field of 0.6 T. Extensive GEANT4 Monte-Carlo
simulations were performed to gain control over the systematic effects. Our
result, , is in agreement with
the Standard-Model value of , which includes recoil-order
corrections that were addressed for the first time for this isotope. Further,
it enables limits to be placed on possible tensor-type charged weak currents as
well as other physics beyond the Standard Model
qBounce: Systematic shifts of transition frequencies of gravitational states of ultra-cold neutrons using Ramsey gravity resonance spectroscopy
qBounce is using quantum states of ultra-cold neutrons in the gravitational
field of the Earth to investigate gravitation in the micrometre range. We
present current measurements taken in 2021 at the Institut Laue-Langevin (ILL)
to determine energy differences of these states by mechanically induced
transitions. This allows a determination of the local acceleration using a
quantum measurement. The data presented here results in .
The classical local value at the experiment is . We present
an analysis of systematic effects that induces shifts of the transition
frequency of order 100 mHz. The inferred value for at the experiment shows
a systematic shift of
Aerodinámica y dinámica del vuelo de alas batientes
En este trabajo se presenta una herramienta de simulación numérica que permite estudiar la aerodinámica no-estacionaria y la dinámica no-lineal asociada al vuelo natural de insectos y aves pequeñas. El modelo aerodinámico utilizado es una versión modificada de la versión 3D del “unsteady vortex lattice method” (UVLM), una generalización del conocido “vortex lattice method”, ampliamente utilizado en flujos incompresibles y estacionarios. La dinámica asociada al insecto se modela mediante un modelo estructural multicuerpo hibrido del insecto completo (cabeza, tórax, abdomen y alas). El desarrollo del modelo está basado en la formulación de Lagrange con coordenadas generalizadas redundantes. Para lograr generalidad y versatilidad en la herramienta desarrollada, se modificó un modelo cinemático desarrollado previamente por los autores de este trabajo para incluir diferentes patrones de deformación sobre el ala (torsión, flexión y ambos efectos combinados). Las alas tienen movimientos prescriptos respecto del cuerpo central, se dice que las alas son cinemáticamente conducidas. La integración numérica de todas las ecuaciones gobernantes, que son diferenciales algebraicas, es realizada simultáneamente e interactivamente en el dominio del tiempo. El esquema de integración usado acopla un método predictor corrector de cuarto orden, el método modificado de Hamming, con un procedimiento de estabilización para las ecuaciones de movimiento resultantes.Fil: Roccia, Bruno A. Universidad Nacional de Río Cuarto. Facultad de Ingeniería; Argentina.Fil: Roccia, Bruno A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Estructuras; Argentina.Fil: Preidikman, Sergio. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Estructuras; Argentina.Fil: Preidikman, Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Massa, Julio C. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Estructuras; Argentina.Fil: Mook, Dean T. Virginia Polytechnic Institute and State University Blacksburg VA. Department of Engineering Sciences and Mechanics; Estados Unidos.Ingeniería Mecánic
An Improved Neutron Electric Dipole Moment Experiment
A new measurement of the neutron EDM, using Ramsey's method of separated
oscillatory fields, is in preparation at the new high intensity source of
ultra-cold neutrons (UCN) at the Paul Scherrer Institute, Villigen, Switzerland
(PSI). The existence of a non-zero nEDM would violate both parity and time
reversal symmetry and, given the CPT theorem, might lead to a discovery of new
CP violating mechanisms. Already the current upper limit for the nEDM
(|d_n|<2.9E-26 e.cm) constrains some extensions of the Standard Model.
The new experiment aims at a two orders of magnitude reduction of the
experimental uncertainty, to be achieved mainly by (1) the higher UCN flux
provided by the new PSI source, (2) better magnetic field control with improved
magnetometry and (3) a double chamber configuration with opposite electric
field directions.
The first stage of the experiment will use an upgrade of the RAL/Sussex/ILL
group's apparatus (which has produced the current best result) moved from
Institut Laue-Langevin to PSI. The final accuracy will be achieved in a further
step with a new spectrometer, presently in the design phase.Comment: Flavor Physics & CP Violation Conference, Taipei, 200
An Improved Search for the Neutron Electric Dipole Moment
A permanent electric dipole moment of fundamental spin-1/2 particles violates
both parity (P) and time re- versal (T) symmetry, and hence, also charge-parity
(CP) symmetry since there is no sign of CPT-violation. The search for a neutron
electric dipole moment (nEDM) probes CP violation within and beyond the Stan-
dard Model. The experiment, set up at the Paul Scherrer Institute (PSI), an
improved, upgraded version of the apparatus which provided the current best
experimental limit, dn < 2.9E-26 ecm (90% C.L.), by the RAL/Sussex/ILL
collaboration: Baker et al., Phys. Rev. Lett. 97, 131801 (2006). In the next
two years we aim to improve the sensitivity of the apparatus to sigma(dn) =
2.6E-27 ecm corresponding to an upper limit of dn < 5E-27 ecm (95% C.L.), in
case for a null result. In parallel the collaboration works on the design of a
new apparatus to further increase the sensitivity to sigma(dn) = 2.6E-28 ecm.Comment: APS Division for particles and fields, Conference Proceedings, Two
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A highly stable atomic vector magnetometer based on free spin precession
We present a magnetometer based on optically pumped Cs atoms that measures
the magnitude and direction of a 1 T magnetic field. Multiple circularly
polarized laser beams were used to probe the free spin precession of the Cs
atoms. The design was optimized for long-time stability and achieves a scalar
resolution better than 300 fT for integration times ranging from 80 ms to 1000
s. The best scalar resolution of less than 80 fT was reached with integration
times of 1.6 to 6 s. We were able to measure the magnetic field direction with
a resolution better than 10 rad for integration times from 10 s up to 2000
s
Testing isotropy of the universe using the Ramsey resonance technique on ultracold neutron spins
Physics at the Planck scale could be revealed by looking for tiny violations
of fundamental symmetries in low energy experiments. In 2008, a sensitive test
of the isotropy of the Universe using has been performed with stored ultracold
neutrons (UCN), this is the first clock-comparison experiment performed with
free neutrons. During several days we monitored the Larmor frequency of neutron
spins in a weak magnetic field using the Ramsey resonance technique. An
non-zero cosmic axial field, violating rotational symmetry, would induce a
daily variation of the precession frequency. Our null result constitutes one of
the most stringent tests of Lorentz invariance to date.Comment: proceedings of the PNCMI2010 conferenc
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