2,445 research outputs found

    Lunar base launch and landing facilities conceptual design

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    The purpose of this study was to perform a first look at the requirements for launch and landing facilities for early lunar bases and to prepared conceptual designs for some of these facilities. The emphasis of the study is on the facilities needed from the first manned landing until permanent occupancy, the Phase 2 lunar base. Factors including surface characteristics, navigation system, engine blast effects, and expected surface operations are used to develop landing pad designs, and definitions fo various other elements of the launch and landing facilities. Finally, the dependence of the use of these elements and the evolution of the facilities are established

    The hierarchy of stability and predictability in orthognathic surgery with rigid fixation: an update and extension

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    A hierarchy of stability exists among the types of surgical movements that are possible with orthognathic surgery. This report updates the hierarchy, focusing on comparison of the stability of procedures when rigid fixation is used. Two procedures not previously placed in the hierarchy now are included: correction of asymmetry is stable with rigid fixation and repositioning of the chin also is very stable. During the first post-surgical year, surgical movements in patients treated for Class II/long face problems tend to be more stable than those treated for Class III problems. Clinically relevant changes (more than 2 mm) occur in a surprisingly large percentage of orthognathic surgery patients from one to five years post-treatment, after surgical healing is complete. During the first post-surgical year, patients treated for Class II/long face problems are more stable than those treated for Class III problems; from one to five years post-treatment, some patients in both groups experience skeletal change, but the Class III patients then are more stable than the Class II/long face patients. Fewer patients exhibit long-term changes in the dental occlusion than skeletal changes, because the dentition usually adapts to the skeletal change

    Partial-Transfer Absorption Imaging: A versatile technique for optimal imaging of ultracold gases

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    Partial-transfer absorption imaging is a tool that enables optimal imaging of atomic clouds for a wide range of optical depths. In contrast to standard absorption imaging, the technique can be minimally-destructive and can be used to obtain multiple successive images of the same sample. The technique involves transferring a small fraction of the sample from an initial internal atomic state to an auxiliary state and subsequently imaging that fraction absorptively on a cycling transition. The atoms remaining in the initial state are essentially unaffected. We demonstrate the technique, discuss its applicability, and compare its performance as a minimally-destructive technique to that of phase-contrast imaging.Comment: 10 pages, 5 figures, submitted to Review of Scientific Instrument

    An Introduction To Cost-Of-Living Adjustments In Public Retirement Plans: Details Matter

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    While financial planning students are expected to be able to understand client retirement plans, subtle differences in cost-of-living adjustments can have major impact on the success of client retirement plans. This teaching note compares the cost-of-living adjustments in the largest government sponsored retirement systems and a hypothetical traditional privately sponsored plan.  Using a Monte Carlo simulation, we estimate the impact on retirement experience from the different COLAs.  These differences are large, with differing protection from future inflation and differing risk for running out of money during retirement. This teaching note will help instructors address Certified Financial Planner (CFP) Board Learning Outcome G.52 “Retirement Needs Analysis”.   The material may also be used in economics, human resources, public administration, and other classes addressing policy aspects of retirement plans

    Gravitational wave detectors based on matter wave interferometers (MIGO) are no better than laser interferometers (LIGO)

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    We show that a recent claim that matter wave interferometers have a much higher sensitivity than laser interferometers for a comparable physical setup is unfounded. We point out where the mistake in the earlier analysis is made. We also disprove the claim that only a description based on the geodesic deviation equation can produce the correct physical result. The equations for the quantum dynamics of non-relativistic massive particles in a linearly perturbed spacetime derived here are useful for treating a wider class of related physical problems. A general discussion on the use of atom interferometers for the detection of gravitational waves is also provided.Comment: 16 pages, REVTeX4; minor changes, one figure and a few references were added, an additional appendix was included where we explain why, contrary to the claims in gr-qc/0409099, the effects due to the reflection off the mirrors cancel out in the final result for the phase shif

    Prospectus, May 28, 1979

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    HERE WE GO AGAIN: REGISTRATION HASSLES; Stugo takes action; \u27Chaos\u27 to highlight beginning of school; Commuter program will help Parkland people save gas; Stugo elections for ten seats is 12-13; Dedication features teleconferencing; Women to show defense; Computer majors eligible for ICP scholarship; Gammon on top of Comm. Dept.; Volunteers are wanted at UI; After registration, it can only get better; More music plays at PC; A quiz from abroad; Honor students total 46; IOC will meet next Tuesday; Dupe dept. is expanding; VA rules upheld in courts; ID rules listed; Slick can hurt Midwest; Parking regulations listed; Top 10 List from WPCD Radio; Athletic schedules: Golf Schedule -- 1979, Cross Country Schedule -- 1979, Women\u27s Volleyball Schedule -- 1979; Roueche suggests using videotapes of lectures; Pres. Staerkel greets students; PC lists job opportunities; Classified Advertising; Advertising Policy; Tickets are on sale on operas; New organization \u27flocks\u27 with others; Tenant Union plant sale will be held next weekend; Women\u27s b-ball to have meeting; Student organizations listed; Fast Freddy forecasts againhttps://spark.parkland.edu/prospectus_1979/1015/thumbnail.jp

    Macrostructural analysis : unravelling polyphase glacitectonic histories

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    Many Pleistocene glacial profiles look extremely simple, comprising till, or glacitectonite, overlying older sediments or bedrock (Figure 4.1). In more complex sequences the till may itself be overlain by younger sediments laid down as the ice retreated or during a completely separate, later phase of advance. Macroscopically, subglacial traction tills (Evans et al., 2007) are typically massive, unstructured deposits suggesting that it should be relatively straightforward to unravel the glacitectonic deformation history recorded by the sequence. Many reconstructions do indeed look very simple, slabs of sediment have been tilted and stacked and then overridden by the glacier to cap the structure with till. Added to this is the use of vertical exaggeration which makes the whole structure look like alpine tectonics (for an example see fig. 5 in van Gijssel, 1987). Dropping the exaggeration led to the recognition that actually we were looking at much more horizontal structures, i.e. overriding nappes and not imbricated slabs (van der Wateren, 1987). Traditionally (van der Meer, 1987) glaciotectonics was thought to relate to large structures like big push moraines and not to smaller structures like drag structures underneath tills (Figure 4.2), let alone to the tills themselves. With the notion that deforming bed tills are tectonically and not sedimentologically structured and could be regarded as tectomicts (Menzies et al., 2006), comes the realisation that glacitectonics happens across a wide range of scales, from the microscopic to tens of kilometres. Only by realising the full range of glaciotectonic scales can we hope to understand the processes
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