22 research outputs found
How to make it faster and at lower cost? B2B integration with semantic web services
Web services and service oriented architectures present a new approach to application integration. While it is reasonable inside an enterprise, it has certain deficiencies when applied in a B2B environment. This deficiencies apply to the discovery, invocation and composition phases, which require considerable manual effort. In the paper, we show on example of a mortgage simulator how these deficiencies can be overcome by applying-semantic web services. The application is compatible with the Web Services Modelling Ontology and makes use of an execution environment automating the processes of discovery, composition and invocation of semantic web services, enabling faster and cheaper B2B application integration
Large amplitude oscillation of a polar crown filament in the pre-eruption phase
We report observation of a large-amplitude filament oscillation followed by
an eruption. This is used to probe the pre-eruption condition and the trigger
mechanism of solar eruptions. We used the EUV images from the
Extreme-Ultraviolet Imaging Telescope on board SOHO satellite and the H-alpha
images from the Flare Monitoring Telescope at Hida Observatory. The observed
event is a polar crown filament that erupted on 15 Oct. 2002. The filament
clearly exhibited oscillatory motion in the slow-rising, pre-eruption phase.
The amplitude of the oscillation was larger than 20 km/s, and the motion was
predominantly horizontal. The period was about 2 hours and seemed to increase
during the oscillation, indicating weakening of restoring force. These results
strongly indicate that, even in the slow-rise phase before the eruption, the
filament retained equilibrium and behaved as an oscillator, and the equilibrium
is stable to nonlinear perturbation. Moreover, the transition from such
nonlinear stability to either instabilities or a loss of equilibrium that leads
to the eruption occurred in the Alfven time scale. This suggests that the onset
of the eruption was triggered by a fast magnetic reconnection that stabilized
the pre-eruption magnetic configuration, rather than by the slow shearing
motion at the photosphere.Comment: 4 pages, 3 figures, accepted for publication in A&
On-disk coronal rain
Small and elongated, cool and dense blob-like structures are being reported
with high resolution telescopes in physically different regions throughout the
solar atmosphere. Their detection and the understanding of their formation,
morphology and thermodynamical characteristics can provide important
information on their hosting environment, especially concerning the magnetic
field, whose understanding constitutes a major problem in solar physics. An
example of such blobs is coronal rain, a phenomenon of thermal non- equilibrium
observed in active region loops, which consists of cool and dense chromospheric
blobs falling along loop-like paths from coronal heights. So far, only off-limb
coronal rain has been observed and few reports on the phenomenon exist. In the
present work, several datasets of on-disk H{\alpha} observations with the CRisp
Imaging SpectroPolarimeter (CRISP) at the Swedish 1-m Solar Telescope (SST) are
analyzed. A special family of on-disk blobs is selected for each dataset and a
statistical analysis is carried out on their dynamics, morphology and
temperatures. All characteristics present distributions which are very similar
to reported coronal rain statistics. We discuss possible interpretations
considering other similar blob-like structures reported so far and show that a
coronal rain interpretation is the most likely one. Their chromospheric nature
and the projection effects (which eliminate all direct possibility of height
estimation) on one side, and their small sizes, fast dynamics, and especially,
their faint character (offering low contrast with the background intensity) on
the other side, are found as the main causes for the absence until now of the
detection of this on-disk coronal rain counterpart.Comment: 18 pages, 10 figures. Accepted for Solar Physic
Dynamism in the solar core
Recent results of a mixed shell model heated asymmetrically by transient
increases in nuclear burning indicate the transient generation of small hot
spots inside the Sun somewhere between 0.1 and 0.2 solar radii. These hot
bubbles are followed by a nonlinear differential equation system with finite
amplitude non-homologous perturbations which is solved in a solar model. Our
results show the possibility of a direct connection between the dynamic
phenomena of the solar core and the atmospheric activity. Namely, an initial
heating about DQ_0 ~ 10^{31}-10^{37} ergs can be enough for a bubble to reach
the outer convective zone. Our calculations show that a hot bubble can arrive
into subphotospheric regions with DQ_final ~ 10^{28} - 10^{34} ergs with a high
speed, up to 10 km s-1, approaching the local sound speed. We point out that
the developing sonic boom transforms the shock front into accelerated particle
beam injected upwards into the top of loop carried out by the hot bubble above
its forefront traveling from the solar interior. As a result, a new perspective
arises to explain flare energetics. We show that the particle beams generated
by energetic deep-origin hot bubbles in the subphotospheric layers have masses,
energies, and chemical compositions in the observed range of solar
chromospheric and coronal flares. It is shown how the emergence of a hot bubble
into subphotospheric regions offers a natural mechanism that can generate both
the eruption leading to the flare and the observed coronal magnetic topology
for reconnection. We show a list of long-standing problems of solar physics
that our model explains. We present some predictions for observations, some of
which are planned to be realized in the near future.Comment: 44 pages, 20 figure
Synthesis of carboxylated derivatives of poly(isobutylene-co-isoprene) by azide–alkyne “click” chemistry
The final publication is available at Springer via https://dx.doi.org/10.1038/s41428-018-0130-yThe synthesis of carboxylated derivatives of poly(isobutylene-co-isoprene) (isobutylene–isoprene rubber, IIR) with substitution levels ranging from 1 to 4 mol% and different spacer lengths was accomplished through azide–alkyne Huisgen cycloaddition. Azido-functionalized IIR was first prepared by reacting brominated IIR with sodium azide to full conversion in a 90:10 tetrahydrofuran/N,N-dimethylacetamide mixture. The click reaction of azido-functionalized IIR with acetylenic acids, which was carried out using the copper(I) bromide/N,N,N′,N″,N″-pentamethyldiethylenetriamine catalyst system in tetrahydrofuran, yielded carboxylated IIRs. The products were characterized by 1H NMR and FT-IR spectroscopy, and their molecular weight was determined by size exclusion chromatography analysis. The conversion to carboxylated groups reached up to 100% as determined by NMR spectroscopy but was highly dependent on the type of solvent and the amounts of catalysts and reactants used in the procedures.ARLANXEO Canada Inc.Natural Sciences and Engineering Research Council (NSERC) of Canad
Exercises in astronomy.
This book is an updated and considerably extended version of Minnaert's work published in 1969 (01.003.051).Many new exercises referring to new observational techniques and methods have been incorporated by the editor in collaboration with the contributing authors D. A. Allen, Z. Ceplechka, S. Ferraz Mello, K. J. Gordon, L. Houziaux, C. Jaschek, Z. Kopal, J. Manfroid, J. Palouš, J. Podolský, G. R. Quast, J. Surdej, A. B. Underhill, J. M. Vreux, D. G. Wentzel.The exercises are organized in the following sections:A. The planetary system: 1. Space and time, instruments. 2. The motions of celestial bodies. 3. Planets and satellites.B. The stars: 1. The Sun. 2. Stars and nebulae. 3. Stellar systems
Simultaneous Longitudinal and Transverse Oscillations in an Active-Region Filament
We report on the co-existence of longitudinal and transverse oscillations in an active-region filament. On March 15, 2013, an M1.1 class flare was observed in Active Region AR 11692. A coronal mass ejection (CME) was found to be associated with the flare. The CME generated a shock wave that triggered the oscillations in a nearby filament, situated south-west of the active region as observed from National Solar Observatory (NSO) Global Oscillation Network Group (GONG) Hα images. In this work we report the longitudinal oscillations in the two ends of the filament, which co-existed with the transverse oscillations. We propose a scenario in which an incoming shock wave hits the filament obliquely and triggers both longitudinal and transverse oscillations. Using the observed parameters, we estimate the lower limit of the magnetic field strength. We use a simple pendulum model with gravity as the restoring force to estimate the radius of curvature. We also calculate the mass accretion rate that causes the filament motions to damp quite fast