87,069 research outputs found
Global helioseismology (WP4.1): From the Sun to the stars & solar analogs
Sun-as-a star observations put our star as a reference for stellar
observations. Here, I review the activities in which the SPACEINN global
seismology team (Working Package WP4.1) has worked during the past 3 years. In
particular, we will explain the new deliverables available on the SPACEINN
seismic+ portal. Moreover, special attention will be given to surface dynamics
(rotation and magnetic fields). After characterizing the rotation and the
magnetic properties of around 300 solar-like stars and defining proper metrics
for that, we use their seismic properties to characterize 18 solar analogues
for which we study their surface magnetic and seismic properties. This allows
us to put the Sun into context compared to its siblings.Comment: Proceedings of the SPACEINN/TASC2/KASC9 meeting. 7 pages, 6 figure
Mode visibilities in radial velocity and intensity Sun-as-a-star helioseismic measurements
We analyze more than 5000 days of Sun-as-a-star radial velocity GOLF and
intensity VIRGO observations to measure the visibilities of the l=0, 1, 2, and
3 modes and the m-amplitude ratios of the l=2 and 3 modes in the solar acoustic
spectrum. We provide observational values that we compare to theoretical
predictions.Comment: SOHO 24 / GONG 2010 conference, to be published in JPC
Drag Coefficients of Varying Dimple Patterns
There are many golf balls on the market today with varying dimple sizes, shapes, and distribution. These proprietary differences are all designed to reduce drag on the balls during flight. There are limited published studies comparing how varying the dimples affects the reduction of drag. An experiment was developed in which golf balls were pulled through a water tank to measure the drag force acting on each ball. The water was chosen to allow for testing at slower velocities. A range of dimple patterns were tested and compared to determine which pattern has the lowest associated drag coefficient
Reliability of an experimental method to analyse the impact point on a golf ball during putting
This study aimed to examine the reliability of an experimental method identifying the location of the impact point on a golf ball during putting. Forty trials were completed using a mechanical putting robot set to reproduce a putt of 3.2 m, with four different putter-ball combinations. After locating the centre of the dimple pattern (centroid) the following variables were tested; distance of the impact point from the centroid, angle of the impact point from the centroid and distance of the impact point from the centroid derived from the X, Y coordinates. Good to excellent reliability was demonstrated in all impact variables reflected in very strong relative (ICC = 0.98–1.00) and absolute reliability (SEM% = 0.9–4.3%). The highest SEM% observed was 7% for the angle of the impact point from the centroid. In conclusion, the experimental method was shown to be reliable at locating the centroid location of a golf ball, therefore allowing for the identification of the point of impact with the putter head and is suitable for use in subsequent studies
Quantum Locality
It is argued that while quantum mechanics contains nonlocal or entangled
states, the instantaneous or nonlocal influences sometimes thought to be
present due to violations of Bell inequalities in fact arise from mistaken
attempts to apply classical concepts and introduce probabilities in a manner
inconsistent with the Hilbert space structure of standard quantum mechanics.
Instead, Einstein locality is a valid quantum principle: objective properties
of individual quantum systems do not change when something is done to another
noninteracting system. There is no reason to suspect any conflict between
quantum theory and special relativity.Comment: Introduction has been revised, references added, minor corrections
elsewhere. To appear in Foundations of Physic
Solar neutrinos, helioseismology and the solar internal dynamics
Neutrinos are fundamental particles ubiquitous in the Universe. Their
properties remain elusive despite more than 50 years of intense research
activity. In this review we remind the reader of the noticeable properties of
these particles and of the stakes of the solar neutrino puzzle. The Standard
Solar Model triggered persistent efforts in fundamental Physics to predict the
solar neutrino fluxes, and its constantly evolving predictions have been
regularly compared to the detected neutrino signals. Anticipating that this
standard model could not reproduce the internal solar dynamics, a SEismic Solar
Model was developed which enriched theoretical neutrino flux predictions with
in situ observation of acoustic waves propagating in the Sun. This review
reminds the historical steps, from the pioneering Homestake detection, the
GALLEX- SAGE captures of the first pp neutrinos and emphasizes the importance
of the Superkamiokande and SNO detectors to demonstrate that the solar-emitted
electronic neutrinos are partially transformed into other neutrino flavors
before reaching the Earth. The success of BOREXINO in detecting the 7 Be
neutrino signal justifies the building of a new generation of detectors to
measure the entire solar neutrino spectrum. A coherent picture emerged from
neutrino physics and helioseismology. Today, new paradigms take shape:
determining the masses of neutrinos and the research on the Sun is focusing on
the dynamical aspects and on signature of dark matter. The third part of the
review is dedicated to this prospect. The understanding of the crucial role of
both rotation and magnetism in solar physics benefit from SoHO, SDO, and PICARD
space observations. For now, the particle and stellar challenges seem
decoupled, but this is only a superficial appearance. The development of
asteroseismology shows the far-reaching impact of Neutrino and Stellar
Astronomy.Comment: 60 pages, 12 figures Invited review in press in Report on Progress in
Physic
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