Koeien kiezen niet voor vreetstanden

Vreetstanden zijn afscheidingen die om de twee vreetplaatsen aan het voerhek gemonteerd zijn. De gedachte is dat koeien met vreetstanden meer rust hebben tijdens het vreten. Uit onderzoek bleek dat de dieren op het High-techbedrijf geen voorkeur hadden voor de gedeelten van het voerhek met vreetstanden

The Metallicity and Carbon-to-oxygen Ratio of the Ultrahot Jupiter WASP-76b from Gemini-S/IGRINS

Measurements of the carbon-to-oxygen (C/O) ratios of exoplanet atmospheres can reveal details about their formation and evolution. Recently, high-resolution cross-correlation analysis has emerged as a method of precisely constraining the C/O ratios of hot Jupiter atmospheres. We present two transits of the ultrahot Jupiter WASP-76b observed between 1.4 and 2.4 μm with the high-resolution Immersion GRating INfrared Spectrometer on the Gemini-S telescope. We detected the presence of H2O, CO, and OH at signal-to-noise ratios of 6.93, 6.47, and 3.90, respectively. We performed two retrievals on this data set. A free retrieval for abundances of these three species retrieved a volatile metallicity of C+OH=−0.70−0.93+1.27 , consistent with the stellar value, and a supersolar carbon-to-oxygen ratio of C/O =0.80−0.11+0.07 . We also ran a chemically self-consistent grid retrieval, which agreed with the free retrieval within 1σ but favored a slightly more substellar metallicity and solar C/O ratio ( C+OH=−0.74−0.17+0.23 and C/O =0.59−0.14+0.13 ). A variety of formation pathways may explain the composition of WASP-76b. Additionally, we found systemic (V sys) and Keplerian (K p ) velocity offsets which were broadly consistent with expectations from 3D general circulation models of WASP-76b, with the exception of a redshifted V sys for H2O. Future observations to measure the phase-dependent velocity offsets and limb differences at high resolution on WASP-76b will be necessary to understand the H2O velocity shift. Finally, we find that the population of exoplanets with precisely constrained C/O ratios generally trends toward super-solar C/O ratios. More results from high-resolution observations or JWST will serve to further elucidate any population-level trends

Tubular structures; the 4th International Symposium, Delft, The Netherlands, June 26, 27 and 28, 1991

Delft University of Technolog

Fatigue behaviour of multiplanar welded hollow section joints and reinforcement measures for repair: FinaLReport, Part IV: Numerical investigation on K-type joints in CHS and RHS in complete girders

Civil Engineering and GeosciencesStructural Engineerin

Fatigue strength of multiplanar welded hollow section joints and reinforcement measures for repair: Sixth technical interim-report (september 1991)

Civil Engineering and GeosciencesStructural Engineerin

Fatigue strength of welded joints in orthotropic steel bridge decks

The fatigue behaviour of welded details in orthotropic steel decks with closed longitudinal stiffeners formed an important part of a joint research project partly funded by the European Coal and Steel Community. Fatigue tests on full scale orthotropic decks and sections of decks were performed and analysed following the procedure used for Eurocode 3, Design of Steel Structures. This paper reviews the tests carried out and presents the fatigue categories obtained, for use by designers. Furthermore, it is intended that these details should be included in Eurocode 3 - Part 2, Steel Bridges and Plated Structures

Into the red: An M-band study of the chemistry and rotation of β Pictoris b at high spectral resolution

High-resolution cross-correlation spectroscopy (HRCCS) combined with adaptive optics has been enormously successful in advancing our knowledge of exoplanet atmospheres, from chemistry to rotation and atmospheric dynamics. This powerful technique now drives major science cases for ELT instrumentation including METIS/ELT, GMTNIRS/GMT and MICHI/TMT, targeting biosignatures on rocky planets at 3–5 μm, but remains untested beyond 3.5 μm where the sky thermal background begins to provide the dominant contribution to the noise. We present 3.51–5.21 μm M-band CRIRES+/VLT observations of the archetypal young directly imaged gas giant β Pictoris b, detecting CO absorption at S/N = 6.6 at 4.73 μm and H2O at S/N = 5.7, and thus extending the use of HRCCS into the thermal background noise dominated infrared. Using this novel spectral range to search for more diverse chemistry we report marginal evidence of SiO at S/N = 4.3, potentially indicative that previously proposed magnesium-silicate clouds in the atmosphere are either patchy, transparent at M-band wavelengths, or possibly absent on the planetary hemisphere observed. The molecular detections are rotationally broadened by the spin of β Pic b, and we infer a planetary rotation velocity of vsin(i) = 22 ± 2 km s−1 from the cross-correlation with the H2O model template, consistent with previous K-band studies. We discuss the observational challenges posed by the thermal background and telluric contamination in the M-band, the custom analysis procedures required to mitigate these issues, and the opportunities to exploit this new infrared window for HRCCS using existing and next-generation instrumentation