1,732,782 research outputs found
Sun direction detection system
One of the detectors is an illumination detector consisting of two spaced apart elongated strips with a strip of cadmium sulphide (Cds) deposited therebetween. Whenever the line image impinges the CdS strip, the resistance between the two other strips is relatively low, while being high when the line image is outside the field of view of the illumination detector. Also included is a sun angle detector which consists of a vapor deposited resistor strip connected at one end to plus 10v and at the other end to minus 10v. Spaced apart from the resistor strip is an elongated strip of low resistance material acting as an output strip, with a CdS strip between the two strips. When the line image is within the field of view of the sun angle detector, the output voltage at the output strip depends on the position of the line image across the sun angle detector
Potential of a sunflower seed by-product as animal fat replacer in healthier Frankfurters
Upcycled defatted sunflower seed flour (SUN), a by-product obtained from sunflower oil extraction, was used as an animal fat replacer to develop healthier frankfurters. For that end, animal fat was replaced (~50%) with water and 2% or 4% of SUN. Nutritional composition, technological, structural and sensorial properties were evaluated. SUN incorporation led to a significant increase in protein, minerals (magnesium, potassium, copper and manganese) and a decrease in fat content (~37% less than control with all animal fat). The incorporation of SUN in frankfurters promoted the presence of phenolic compounds. Increasing SUN addition lead to an increasingly (p < 0.05) darker frankfurter colour. Samples with SUN at 4% were firmer than the control according to TPA and sensory analysis results and showed the highest lipid disorder attributed to more lipid interactions in the meat matrix. SUN addition as an animal fat replacer in frankfurters is a feasible strategy to valorise sunflower oil by-products and obtain healthier frankfurters
Heating of near-Earth objects and meteoroids due to close approaches to the Sun
It is known that near-Earth objects (NEOs) during their orbital evolution may
often undergo close approaches to the Sun. Indeed it is estimated that up to
~70% of them end their orbital evolution colliding with the Sun. Starting from
the present orbital properties, it is possible to compute the most likely past
evolution for every NEO, and to trace its distance from the Sun. We find that a
large fraction of the population may have experienced in the past frequent
close approaches, and thus, as a consequence, a considerable Sun-driven
heating, not trivially correlated to the present orbits. The detailed dynamical
behaviour, the rotational and the thermal properties of NEOs determine the
exact amount of the resulting heating due to the Sun. In the present paper we
discuss the general features of the process, providing estimates of the surface
temperature reached by NEOs during their evolution. Moreover, we investigate
the effects of this process on meteor-size bodies, analyzing possible
differences with the NEO population. We also discuss some possible effects of
the heating which can be observed through remote sensing by ground-based
surveys or space missions.Comment: 8 pages, 5 figures, accepted by MNRA
Airborne tracking sunphotometer apparatus and system
An airborne tracking Sun photometer apparatus has a rotatable dome. An azimuth drive motor is connected to rotate the dome. The dome has an equatorial slot. A cylindrical housing is pivotally mounted inside the dome at the equatorial slot. A photometer is mounted in the housing to move in the equatorial slot as the housing pivots. The photometer has an end facing from the slot with an optical flat transparent window. An elevation drive motor is connected to pivot the cylindrical housing. The rotatable dome is mounted in the bulkhead of an aircraft to extend from the interior of the aircraft. A Sun sensor causes the photometer to track the Sun automatically. Alternatively, the photometer may be oriented manually or by computer
Gravity tests with INPOP planetary ephemerides
In this paper, we present several gravity tests made in using the last
INPOP08 planetary ephemerides. We first propose two methods to estimate the PPN
parameter and its correlated value, the Sun J2 and we discuss the
correlation between the Sun J2 and the mass of the asteroid ring. We estimate
possible advance in the planet perihelia. In the end we show that no constant
acceleration larger than 1/4 the Pioneer anomaly can affect the planets of our
solar system.Comment: 11 pages. submitted to proceedings of IAU symposium 264 "Relativity
in Fundamental Astronomy: Dynamics, Reference Frames and Data analysis
Optimisation of Low-Thrust and Hybrid Earth-Moon Transfers
This paper presents an optimization procedure to generate fast and low-∆v Earth-Moon transfer trajectories, by exploiting the multi-body dynamics of the Sun-Earth-Moon system. Ideal (first-guess) trajectories are generated at first, using two coupled planar circular restricted three-body problems, one representing the Earth-Moon system, and one representing the Sun-Earth. The trajectories consist of a first ballistic arc in the Sun-Earth system, and a second ballistic arc in the Earth-Moon system. The two are connected at a patching point at one end (with an instantaneous ∆v), and they are bounded at Earth and Moon respectively at the other end. Families of these trajectories are found by means of an evolutionary optimization method. Subsequently, they are used as first-guess for solving an optimal control problem, in which the full three-dimensional 4-body problem is introduced and the patching point is set free. The objective of the optimisation is to reduce the total ∆v, and the time of flight, together with introducing the constraints on the transfer boundary conditions and of the considered propulsion technology. Sets of different optimal trajectories are presented, which represents trade-off options between ∆v and time of flight. These optimal transfers include conventional solar-electric low-thrust and hybrid chemical/solar-electric high/low-thrust, envisaging future spacecraft that can carry both systems. A final comparison is made between the optimal transfers found and only chemical high-thrust optimal solutions retrieved from literature
Kepler-7b: A Transiting Planet with Unusually Low Density
We report the discovery and confirmation of Kepler-7b, a transiting planet
with unusually low density. The mass is less than half that of Jupiter, Mp =
0.43 Mj, but the radius is fifty percent larger, Rp = 1.48 Rj. The resulting
density, 0.17 g/cc, is the second lowest reported so far for an extrasolar
planet. The orbital period is fairly long, P = 4.886 days, and the host star is
not much hotter than the Sun, Teff = 6000 K. However, it is more massive and
considerably larger than the sun, Mstar = 1.35 Msun and Rstar = 1.84 Rsun, and
must be near the end of its life on the Main Sequence.Comment: 19 pages, 3 figure
Gaia: The Astrometry Revolution
The power of micro-arcsecond (as) astrometry is about to be unleashed.
ESA's Gaia mission, now headed towards the end of the first year of routine
science operations, will soon fulfil its promise for revolutionary science in
countless aspects of Galactic astronomy and astrophysics. The potential of Gaia
position measurements for important contributions to the astrophysics of
planetary systems is huge. We focus here on the expectations for detection and
improved characterization of 'young' planetary systems in the neighborhood of
the Sun using a combination of Gaia as astrometry and direct imaging
techniques.Comment: 6 pages, 3 figures, to appear in the Proceedings of IAU Symposium 314
'Young Stars & Planets Near the Sun', held on May 11-15 2015 in Atlanta (GA),
USA (J. H. Kastner, B. Stelzer, & S. A. Metchev, eds.
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