In control processes, sometimes it would be necessary to know variables at locations that are barely accessible. In such cases, soft sensors (also known as "virtual sensors") could really help. In ...fact, they are powerful instruments for the indirect measure of quantities that would not be measurable, if not with the installation of physical sensors that could perturbate the normal working conditions of the system under test. In this paper, the authors describe an approach to indirectly measure temperature values in a brew group of a professional coffee machine. A finite element (FE) model simulating both the fluid dynamics and the thermal distribution on the group was developed and validated by dedicated experimental tests. The FE model was then exploited to feed an autoregressive exogenous model autoregressive with eXogenous input (ARX) model linking the temperature in the boiler (i.e., a quantity ordinarily assessed in the coffee machine) and the one near the water output, where otherwise a hardware sensor would compromise the correct coffee brewing process and the safety/quality of the brewed coffee. The obtained data-driven soft sensor can help to improve the control unit architecture of the coffee machine.
Tumbling asteroids Pravec, P.; Harris, A.W.; Scheirich, P. ...
Icarus (New York, N.Y. 1962),
2005, 2005-1-00, 20050101, Letnik:
173, Številka:
1
Journal Article
Recenzirano
We present both a review of earlier data and new results on non-principal axis rotators (tumblers) among asteroids. Among new tumblers found, the best data we have are for 2002 TD
60, 2000 WL
107, ...and (54789) 2001 MZ
7—each of them shows a lightcurve with two frequencies (full terms with linear combinations of the two frequencies are present in the lightcurve). For 2002 TD
60, we have constructed a physical model of the NPA rotation. Other recent objects which have been found to be likely tumblers based on their lightcurves that do not fit with a single periodicity are 2002 NY
40, (16067) 1999 RH
27, and (5645) 1990 SP. We have done a statistical analysis of the present sample of the population of NPA rotators. It appears that most asteroids larger than
∼
0.4
km
with estimated damping timescales (Harris, 1994, Icarus 107, 209) of 4.5 byr and longer are NPA rotators. The statistic of two short-period tumblers (
D
=
0.04
and 0.4 km) with non-zero tensile strength suggests that for them the quantity
μ
Q
/
T
, where
μ is the mechanical rigidity,
Q is the elastic dissipation factor, and
T is a spin excitation age (i.e., a time elapsed since the last significant spin excitation event), is greater by two to four orders of magnitude than the larger, likely rubble-pile tumblers. Among observational conditions and selection effects affecting detections of NPA rotations, there is a bias against detection of low-amplitude (small elongation) tumblers.
Abstract
During the 2014–2015 mutual events season, the Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE), Paris, France, and the Sternberg Astronomical Institute (SAI), Moscow, ...Russia, led an international observation campaign to record ground-based photometric observations of Galilean moon mutual occultations and eclipses. We focused on processing the complete photometric observations data base to compute new accurate astrometric positions. We used our method to derive astrometric positions from the light curves of the events. We developed an accurate photometric model of mutual occultations and eclipses, while correcting for the satellite albedos, Hapke's light scattering law, the phase effect, and the limb darkening. We processed 609 light curves, and we compared the observed positions of the satellites with the theoretical positions from IMCCE NOE-5-2010-GAL satellite ephemerides and INPOP13c planetary ephemeris. The standard deviation after fitting the light curve in equatorial positions is ±24 mas, or 75 km at Jupiter. The rms (O−C) in equatorial positions is ±50 mas, or 150 km at Jupiter.
Amateur contributions to professional publications have increased exponentially over the last decades in the field of planetary astronomy. Here we review the different domains of the field in which ...collaborations between professional and amateur astronomers are effective and regularly lead to scientific publications.We discuss the instruments, detectors, software and methodologies typically used by amateur astronomers to collect the scientific data in the different domains of interest. Amateur contributions to the monitoring of planets and interplanetary matter, characterization of asteroids and comets, as well as the determination of the physical properties of Kuiper Belt Objects and exoplanets are discussed.
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