3,974 research outputs found
NASA Lunabotics Mining Competition for Universities: Results and Lessons Learned
Space Mining for resources such as water ice, and regolith, which contain many elements in the form of metals, minerals, volatiles and other compounds, is a necessary step in Space Resource Utilization. One of the primary goals is to extract propellants from the regolith such as oxygen and hydrogen which could then be used for in-space transportation. In addition, the space mining system can be used for various construction tasks that can benefit human and robotic exploration as well as scientific investigations based on the exposed topography. The National Aeronautics & Space Administration (NASA) Lunabotics Mining Competition is a university-level competition designed to engage and retain students in science, technology, engineering and mathematics (STEM). NASA will directly benefit from the competition by encouraging the development of innovative lunar excavation concepts from universities which may result in clever ideas and solutions which could be applied to an actual lunar excavation device or payload. The challenge is for students to design and build a remote controlled or autonomous excavator, called a lunabot, that can collect and deposit a minimum of 10 kilograms of lunar simulant within 15 minutes. The complexities of the challenge include the abrasive characteristics of the lunar simulant, the weight and size limitations of the lunabot, and the ability to control the lunabot from a remote control center. This paper will present the results of the first and second annual Lunabotics Mining Competitions held in May 2010 and May 2011. In 2010, 22 United States (US) universities competed, and in May 2011 the competition was opened to international participation, with 46 Universities expected to attend. There are 12 international teams and 34 US teams. This combined total directly inspired an estimated 544 university students. More students and the public were engaged via internet broadcasting and social networking media. The various designs will be cataloged and categorized to provide information to future Lunabotics mining robot designers and competitors. It is also expected to be of value for actual future space missions, as knowledge is gained from testing many innovative prototypes in simulated lunar regolith
Personal computer use at Navy Field Activities: a productivity study
In the past, corporations justified investment in office automation (OA) by vague claims of increased productivity. Now, managers are reevaluating their productivity measurement systems in an effort to identify productivity gains resulting from OA. The purpose of this thesis is to present a methodology for determining the impact of OA on office productivity. This study examined the productivity of the Standard Automated Contracting System for Federal Agencies (SACONS), in a before/after quasi-experimental design that measured outputs (volume, quality of work), inputs (staff size, grade structure, overtime usage), and by-product social effects (morale, teamwork) using archival data. This framework, developed in a previous SACONS study, is used to analyze the strength of SACONS software. The results of this study were confounded by external events that adversely affected our results. Only the quality of work measure (Procurement Action Lead Time), which was reduced by 13 percent, showed a significant productivity gain. Further study of SACONS is necessary to determine its impact on office productivityhttp://archive.org/details/personalcomputer00murpNAU.S. Navy (U.S.N.) authors
High Abundance of Nesting Long-Eared Owls in North Dakota
The long-eared owl (Asio otus) is a secretive, poorly understood species in the Great Plains of the United States and Canada. In North Dakota the long-eared owl has been considered a species of special concern (Petersen 1991), due mainly to lack of information on its occurrence and nesting status. We discovered 39 long-eared owl nests while searching for Cooper\u27s hawk (Accipiter cooperii) nests in northwestern and north central North Dakota during April and May 2000. Long-eared owl nests mainly were observed at J. Clark Salyer and Des Lacs National Wildlife Refuges (NWRs) in the Souris River basin (for study area descriptions see Nenneman et al. 2002) and at Lostwood NWR on the Missouri Coteau landform (Murphy 1993). These 39 nests exceed the total of all state breeding records for the long-eared owl through the early 1970\u27s (Stewart 1975: 159). During 1994 to 1999 we annually found 2 to 12 long-eared owl nests while searching for Cooper\u27s hawk nests in approximately the same area of North Dakota
Amine- and Sulfide-sensing Copper(I) Iodide Films
Copper(I) iodide films were cast onto glass from solution. The CuI films absorb vapor-phase amine and sulfide molecules, producing a range of photoluminescent emission colors. Spectroscopic data suggest the presence of low energy CuI cluster-centered transitions
Focusing a deterministic single-ion beam
We focus down an ion beam consisting of single 40Ca+ ions to a spot size of a
few mum using an einzel-lens. Starting from a segmented linear Paul trap, we
have implemented a procedure which allows us to deterministically load a
predetermined number of ions by using the potential shaping capabilities of our
segmented ion trap. For single-ion loading, an efficiency of 96.7(7)% has been
achieved. These ions are then deterministically extracted out of the trap and
focused down to a 1sigma-spot radius of (4.6 \pm 1.3)mum at a distance of 257mm
from the trap center. Compared to former measurements without ion optics, the
einzel-lens is focusing down the single-ion beam by a factor of 12. Due to the
small beam divergence and narrow velocity distribution of our ion source,
chromatic and spherical aberration at the einzel-lens is vastly reduced,
presenting a promising starting point for focusing single ions on their way to
a substrate.Comment: 16 pages, 7 figure
Discovery of three new near-pristine absorption clouds at -4.4
We report the discovery of three new "near-pristine" Lyman Limit Systems
(LLSs), with metallicities ~1/1000 solar, at redshifts 2.6, 3.8 and 4.0, with a
targeted survey at the Keck Observatory. High resolution echelle spectra of
eight candidates yielded precise column densities of hydrogen and weak, but
clearly detected, metal lines in seven LLSs; we previously reported the one
remaining, apparently metal-free LLS, to have metallicity <1/10000 solar.
Robust photoionisation modelling provides metallicities [Si/H] = -3.05 to
-2.94, with 0.26 dex uncertainties (95% confidence) for three LLSs, and [Si/H]
>~ -2.5 for the remaining four. Previous simulations suggest that near-pristine
LLSs could be the remnants of PopIII supernovae, so comparing their detailed
metal abundances with nucleosynthetic yields from supernovae models is an
important goal. Unfortunately, at most two different metals were detected in
each new system, despite their neutral hydrogen column densities
(10^{19.2-19.4} cm^{-2}) being two orders of magnitude larger than the two
previous, serendipitously discovered near-pristine LLSs. Nevertheless, the
success of this first targeted survey for near-pristine systems demonstrates
the prospect that a much larger, future survey could identify clear
observational signatures of PopIII stars. With a well-understood selection
function, such a survey would also yield the number density of near-pristine
absorbers which, via comparison to future simulations, could reveal the
origin(s) of these rare systems.Comment: Accepted by MNRAS. 21 pages, 27 figure
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