265 research outputs found
An experimental investigation of a fully cavitating two-dimensional flat plate hydrofoil near a free surface
An experimental program was conducted to investigate the characteristics of a fully cavitating two-dimensional flat plate hydrofoil in the presence of a free surface. The submergence of the hydrofoil was varied from the planing condition at the free surface to a depth corresponding to 2.16 model chords. Near the surface the cavities formed by venting to the atmosphere, but at the deeper submergences, they had to be artificially formed by supplying them with air.
The normal force, the moment about the leading edge, the center of pressure location, the cavity length, and the volumetric air flow rate into the cavity are presented as functions of angle of attack, cavitation number, Froude number, and proximity to the free surface
Seedling tolerance as a factor in bottomland timber succession
Report on Department of Forestry Research Project 123, 'Ecological Studies'--P. [2].Digitized 2007 AES.Includes bibliographical references (page 11)
Influence of geologic parent material and climate on distribution of shortleaf pine in Missouri
This bulletin is a report on Department of Forestry Research Project 260, 'Soil and Species'--P. [2].Digitized 2007 AES.Includes bibliographical references (pages 27-28)
Influence of light and nutrition on color and growth of redcedar seedlings
Digitized 2007 AES.Includes bibliographical references (page 15)
Pin oak acorn production and regeneration as affected by stand density, structure and flooding
Digitized 2007 AES.Includes bibliographical references (page 24)
Search for stable Strange Quark Matter in lunar soil
We report results from a search for strangelets (small chunks of Strange
Quark Matter) in lunar soil using the Yale WNSL accelerator as a mass
spectrometer. We have searched over a range in mass from A=42 to A=70 amu for
nuclear charges 5, 6, 8, 9, and 11. No strangelets were found in the
experiment. For strangelets with nuclear charge 8, a concentration in lunar
soil higher than is excluded at the 95% confidence level. The
implied limit on the strangelet flux in cosmic rays is the most sensitive to
date for the covered range and is relevant to both recent theoretical flux
predictions and a strangelet candidate event found by the AMS-01 experiment.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let
ProtoDESI: First On-Sky Technology Demonstration for the Dark Energy Spectroscopic Instrument
The Dark Energy Spectroscopic Instrument (DESI) is under construction to
measure the expansion history of the universe using the baryon acoustic
oscillations technique. The spectra of 35 million galaxies and quasars over
14,000 square degrees will be measured during a 5-year survey. A new prime
focus corrector for the Mayall telescope at Kitt Peak National Observatory will
deliver light to 5,000 individually targeted fiber-fed robotic positioners. The
fibers in turn feed ten broadband multi-object spectrographs. We describe the
ProtoDESI experiment, that was installed and commissioned on the 4-m Mayall
telescope from August 14 to September 30, 2016. ProtoDESI was an on-sky
technology demonstration with the goal to reduce technical risks associated
with aligning optical fibers with targets using robotic fiber positioners and
maintaining the stability required to operate DESI. The ProtoDESI prime focus
instrument, consisting of three fiber positioners, illuminated fiducials, and a
guide camera, was installed behind the existing Mosaic corrector on the Mayall
telescope. A Fiber View Camera was mounted in the Cassegrain cage of the
telescope and provided feedback metrology for positioning the fibers. ProtoDESI
also provided a platform for early integration of hardware with the DESI
Instrument Control System that controls the subsystems, provides communication
with the Telescope Control System, and collects instrument telemetry data.
Lacking a spectrograph, ProtoDESI monitored the output of the fibers using a
Fiber Photometry Camera mounted on the prime focus instrument. ProtoDESI was
successful in acquiring targets with the robotically positioned fibers and
demonstrated that the DESI guiding requirements can be met.Comment: Accepted versio
The High-redshift Clusters Occupied by Bent Radio AGN (COBRA) Survey: Investigating the Role of Environment on Bent Radio AGNs Using LOFAR
© 2023. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Bent radio active galactic nucleus (AGN) morphology depends on the density of the surrounding gas. However, bent sources are found inside and outside clusters, raising the question of how environment impacts bent AGN morphology. We analyze new LOw-Frequency Array the LOFAR Two-metre Sky Survey (LoTSS) Data Release II observations of 20 bent AGNs in clusters and 15 not in clusters from the high-z Clusters Occupied by Bent Radio AGN (COBRA) survey (0.35 1.2 Mpc) or bent AGNs in weaker groups rather than the field.Peer reviewe
- …