3,587 research outputs found
Bismuth incorporation and the role of ordering in GaAsBi/GaAs structures
The structure and composition of single GaAsBi/GaAs epilayers grown by molecular beam epitaxy were investigated by optical and transmission electron microscopy techniques. Firstly, the GaAsBi layers exhibit two distinct regions and a varying Bi composition profile in the growth direction. In the lower (25 nm) region, the Bi content decays exponentially from an initial maximum value, while the upper region comprises an almost constant Bi content until the end of the layer. Secondly, despite the relatively low Bi content, CuPtB-type ordering was observed both in electron diffraction patterns and in fast Fourier transform reconstructions from high-resolution transmission electron microscopy images. The estimation of the long-range ordering parameter and the development of ordering maps by using geometrical phase algorithms indicate a direct connection between the solubility of Bi and the amount of ordering. The occurrence of both phase separation and atomic ordering has a significant effect on the optical properties of these layers
Del Sistema al Prototipo y viceversa (el caso de la GBH + INVISO)
Main subject of this article is showing how most of famous manufacturing houses of XX Century are not only single prototypes, but they really are part of general system from upper level (system they want testing). Also, we can prove how this kind of generation don’t running “from Prototype to the System” (by single juxtaposition of the model to increase scale). On contrary way this prototypes are the result of inverse procedure (after, they will be as feed-back to refine start system).
To this purpose the article show 5 historic cases as background within this behavior line, and INVISO winner and GBHouse are analyze most deep. From this studio we can get some conclusion about relation between “General Theory of Systems” and “open industrialization” premises give to S.3c (System constructed by compatibles components): as flexibility or recycling, and how we can get it through proving procedures.La mayoría de las viviendas industriales famosas del SXX no son solo eso (prototipos individuales): forman parte de un sistema general de grado muy superior para ponerlo a prueba. Se demuestra en este artículo como el recorrido en esta clase de concepción productiva no se efectúa “desde el prototipo al sistema” por una simple adición del modelo; al contrario, estos prototipos resultan del camino inverso, para luego sí, servir como feed-back.
Se muestran 5 antecedentes históricos dentro de este recorrido, y se analizan más a fondo el Primer premio del concurso INVIso y la casa GBH. De su estudio se derivan algunas conclusiones en cuanto a la relación entre la Teoría General de Sistemas y las premisas que la Industrialización Abierta confiere a los Sistemas construidos a partir de componentes compatibles (S.3c), como la flexibilidad, o el reciclaje, y la manera de conseguir que estas se cumplan mediante procedimientos probados
An infinite family of magnetized Morgan-Morgan relativistic thin disks
Applying the Horsk\'y-Mitskievitch conjecture to the empty space solutions of
Morgan and Morgan due to the gravitational field of a finite disk, we have
obtained the corresponding solutions of the Einstein-Maxwell equations. The
resulting expressions are simply written in terms of oblate spheroidal
coordinates and the solutions represent fields due to magnetized static thin
disk of finite extension. Now, although the solutions are not asymptotically
flat, the masses of the disks are finite and the energy-momentum tensor agrees
with the energy conditions. Furthermore, the magnetic field and the circular
velocity show an acceptable physical behavior.Comment: Submitted to IJTP. This paper is a revised and extended version of a
paper that was presented at arXiv:1006.203
Resonance phenomena of a solitonlike extended object in a bistable potential
We investigate the dynamics of a soliton that behaves as an extended
particle. The soliton motion in an effective bistable potential can be chaotic
in a similar way as the Duffing oscillator. We generalize the concept of
geometrical resonance to spatiotemporal systems and apply it to design a
nonfeedback mechanism of chaos control using localized perturbations.We show
the existence of solitonic stochastic resonance.Comment: 3 postscript figure
3D numerical model of the Omega Nebula (M17): simulated thermal X-ray emission
We present 3D hydrodynamical simulations of the superbubble M17, also known
as the Omega nebula, carried out with the adaptive grid code yguazu'-a, which
includes radiative cooling. The superbubble is modelled considering the winds
of 11 individual stars from the open cluster inside the nebula (NGC 6618), for
which there are estimates of the mass loss rates and terminal velocities based
on their spectral types. These stars are located inside a dense interstellar
medium, and they are bounded by two dense molecular clouds.
We carried out three numerical models of this scenario, considering different
line of sight positions of the stars (the position in the plane of the sky is
known, thus fixed). Synthetic thermal X-ray emission maps are calculated from
the numerical models and compared with ROSAT observations of this astrophysical
object. Our models reproduce successfully both the observed X-ray morphology
and the total X-ray luminosity, without taking into account thermal conduction
effects.Comment: 8 pages, 6 figures, accepted for publication in MNRA
Differences between adjusted vs. non- adjusted loads in velocity-based training: consequences for strength training control and programming
Strength and conditioning specialists commonly deal with the quantification and
selection the setting of protocols regarding resistance training intensities. Although
the one repetition maximum (1RM) method has been widely used to prescribe exercise
intensity, the velocity-based training (VBT) method may enable a more optimal tool
for better monitoring and planning of resistance training (RT) programs. The aim of
this study was to compare the effects of two RT programs only differing in the training
load prescription strategy (adjusting or not daily via VBT) with loads from 50 to 80%
1RM on 1RM, countermovement (CMJ) and sprint. Twenty-four male students with
previous experience in RT were randomly assigned to two groups: adjusted loads (AL)
(nD13) and non-adjusted loads (NAL) (nD11) and carried out an 8-week (16 sessions)
RT program. The performance assessment pre- and post-training program included
estimated 1RM and full load-velocity profile in the squat exercise; countermovement
jump (CMJ); and 20-m sprint (T20). Relative intensity (RI) and mean propulsive
velocity attained during each training session (Vsession) was monitored. Subjects in the
NAL group trained at a significantly faster Vsession than those in AL (p < 0.001) (0.88 -
0.91 vs. 0.67- 0.68 m/s, with a 15% RM gap between groups for the last sessions), and
did not achieve the maximum programmed intensity (80% RM). Significant differences
were detected in sessions 3- 4, showing differences between programmed and performed
Vsession and lower RI and velocity loss (VL) for the NAL compared to the AL group
(p < 0.05). Although both groups improved 1RM, CMJ and T20, NAL experienced
greater and significant changes than AL (28.90 vs.12.70%, 16.10 vs. 7.90% and -1.99 vs.
- 0.95%, respectively). Load adjustment based on movement velocity is a useful way to
control for highly individualised responses to training and improve the implementation
of RT programs
X-ray emission and dynamics from large diameter superbubbles: The case of N 70 superbubble
The morphology, dynamics and thermal X-ray emission of the superbubble N70 is
studied by means of 3D hydrodynamical simulations, carried out with the
{\sc{yguaz\'u-a}} code. We have considered different scenarios: the superbubble
being the product of a single supernova remnant, of the stellar winds from an
OB association, or the result of the joint action of stellar winds and a
supernova event. Our results show that, in spite that all scenarios produce
bubbles with the observed physical size, only those where the bubble is driven
by stellar winds and a SN event are successful to explain the general
morphology, dynamics and the X-ray luminosity of N70. Our models predict
temperatures in excess of at the interior of the superbubble,
however the density is too low and the emission in thermal X-ray above is too faint to be detected.Comment: 9 pages, 11 figures, ApJ accepte
RF plasma cleaning of optical surfaces: A study of cleaning rates on different carbon allotropes as a function of RF powers and distances
An extended study on an advanced method for the cleaning of carbon
contaminations on large optical surfaces using a remote inductively coupled low
pressure RF plasma source (GV10x downstream asher) is reported in this work.
Technical as well as scientific features of this scaled up cleaning process are
analyzed, such as the cleaning efficiency for different carbon allotropes
(amorphous and diamond-like carbon) as a function of feedstock gas composition,
RF power (ranging from 30 to 300W), and source-object distances (415 to 840
mm). The underlying physical phenomena for these functional dependences are
discussed.Comment: 16 pages, 9 figure
- …