Science.gov

Sample records for toivo univer ao

  1. La matiere noire dans l'Univers.

    NASA Astrophysics Data System (ADS)

    Mamon, G.

    Parmi les mille questions que l'on peut se poser sur l'Univers, les plus fondamentales concernent son contenu : De quoi est faite la matière de l'Univers ? Est-ce que la matière de l'Univers est principalement constituée d'étoiles, ou bien de gaz interstellaire, de poussières interstellaires, de planètes, petits astéroïdes, ou de trous noirs ? Ou doit-on admettre que l'Univers est composé d'une autre forme de matière que l'on ne connaît pas, qui serait basée sur des particules élémentaires plus exotiques que les protons, neutrons et électrons qui constituent la matière ordinaire, dite baryonique?

  2. Les couleurs de l'Univers

    NASA Astrophysics Data System (ADS)

    Nazé, Yaël

    2005-10-01

    À quoi ressemble la Voie lactée dans l'ultraviolet ? Que cachent les nuages de poussière qui voilent des parties entières du ciel ? Avec la découverte des ondes électromagnétiques (ondes radio, ultraviolet, infrarouge, rayons X, gamma), le ciel s'est teinté de nouvelles couleurs, changeant totalement d'aspect, jusqu'à révéler des phénomènes d'une violence insoupçonnée. Les télescopes du monde entier obtiennent maintenant des images d'un univers inconnu que l'auteur nous apprend à comprendre. Riche en anecdotes parfois cocasses sur des découvertes qui doivent parfois au hasard ou à la persévérance obstinée de chercheurs, le livre invite le lecteur à découvrir un monde invisible à l'oeil. Des mystérieux quasars au rayonnement cosmologique, c'est à un voyage au fil de ce nouvel arc-en-ciel que nous convie l'auteur.

  3. Cosmicflows Constrained Local UniversE Simulations

    NASA Astrophysics Data System (ADS)

    Sorce, Jenny G.; Gottlöber, Stefan; Yepes, Gustavo; Hoffman, Yehuda; Courtois, Helene M.; Steinmetz, Matthias; Tully, R. Brent; Pomarède, Daniel; Carlesi, Edoardo

    2016-01-01

    This paper combines observational data sets and cosmological simulations to generate realistic numerical replicas of the nearby Universe. The latter are excellent laboratories for studies of the non-linear process of structure formation in our neighbourhood. With measurements of radial peculiar velocities in the local Universe (cosmicflows-2) and a newly developed technique, we produce Constrained Local UniversE Simulations (CLUES). To assess the quality of these constrained simulations, we compare them with random simulations as well as with local observations. The cosmic variance, defined as the mean one-sigma scatter of cell-to-cell comparison between two fields, is significantly smaller for the constrained simulations than for the random simulations. Within the inner part of the box where most of the constraints are, the scatter is smaller by a factor of 2 to 3 on a 5 h-1 Mpc scale with respect to that found for random simulations. This one-sigma scatter obtained when comparing the simulated and the observation-reconstructed velocity fields is only 104 ± 4 km s-1, i.e. the linear theory threshold. These two results demonstrate that these simulations are in agreement with each other and with the observations of our neighbourhood. For the first time, simulations constrained with observational radial peculiar velocities resemble the local Universe up to a distance of 150 h-1 Mpc on a scale of a few tens of megaparsecs. When focusing on the inner part of the box, the resemblance with our cosmic neighbourhood extends to a few megaparsecs (<5 h-1 Mpc). The simulations provide a proper large-scale environment for studies of the formation of nearby objects.

  4. Les surfaces croches de l'univers d'Einstein

    NASA Astrophysics Data System (ADS)

    Lareau-Dussault, Rosemonde

    Dans ce mémoire, on introduit l'univers d'Einstein et on présente plusieurs façons conceptuelles et paramétriques de représenter cet espace. On présente ensuite différents objets de l'univers d'Einstein. L'accent est mis sur la visualisation de ces objets en dimension deux et trois. Finalement, on décrit les surfaces croches. Les surfaces croches servent à borner des domaines fondamentaux, de la même façon que les surfaces équidistantes le font en géométrie euclidienne. Le but de ce mémoire est de présenter certaines propriétés des surfaces croches. En particulier, on montre qu'elles ont deux côtés. Si ce n'était pas le cas, il serait impossible de trouver des surfaces croches disjointes. Mots clés : Structures lorentziennes, Univers d'Einstein, Géométrie conforme, Action de groupe, Groupe associé à une surface.

  5. Jayant Narlikar : dernier rempart de l'Univers stationnaire

    NASA Astrophysics Data System (ADS)

    Bonnet-Bidaud, J. M.

    2005-04-01

    "Travailler dans une seule direction ne prouve pas que cela soit la bonne". L'astrophysicien indien, Jayant Narlikar prone la diversité des approches en recherche fondamentale - c'est bien le moins pour ce tenant de l'Univers stationnaire, théorie alternative à celle du Big Bang. Mais, selon lui, une telle démarche devient rare en cosmologie, malheureusement.

  6. 41. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. NORTH DAM OF MILNER DAM; DOWNSTREAM AFTER TUNNEL CLOSURE; SILT BERM COMING THROUGH DAM. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  7. 73. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    73. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. SILT FILTERING 'THROUGH NORTH DAM; NORTH DAM FROM DOWNSTREAM SHOWING DIRT FILL FILTERING THROUGH DAM. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  8. 48. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    48. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. MILNER DAM; WEST VIEW ACROSS DAM FROM MIDDLE DAM; SNAKE RIVER EXITING FROM TUNNELS. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  9. 38. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. NORTH DAM AT MILNER DAM; NORTH VIEW, UPPER SLOPE OF MAIN CHANNEL DAM, DIRT FILL CONTINUING. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  10. 81. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    81. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, date unknown. DRY CREEK DAM, TWIN FALLS COUNTY, SOUTH OF MURTAUGH, IDAHO; DRIVING SHEET PILING TO SHUT OFF SEEPAGE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  11. UniverSIS: Flexible System, Easy To Change.

    ERIC Educational Resources Information Center

    Miller, Robert; Johnson, Bruce; Woolfolk, Walter W.

    2002-01-01

    Identifies characteristics of a flexible information system, using UniverSIS--a student information system developed at the University of Cincinnati--to illustrate principles of flexible design. Benefits include increased business control over system behavior, reuse of system solutions, and reduced involvement of technical staff as business…

  12. 64. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    64. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. MILNER DAM. WATER FLOODING OVER SPILLWAY FOR FIRST TIME. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  13. 51. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    51. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. MILNER DAM, INSPECTION OF GATES PRIOR TO CLOSURE; DISASSEMBLING CRANE TOWER AT LEFT. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  14. 76. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    76. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, date unknown. DISASSEMBLING CRANE TOWER FROM SOUTH ISLAND SPILLWAY. REMOVING CABLE TOWER. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  15. 50. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. MILNER DAM TUNNELS. CHANNEL APPROACHING TUNNELS; SNAKE RIVER PASSING THROUGH. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  16. 53. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. MILNER DAM TUNNEL CHANNEL AND APPROACH TO TUNNEL GATES. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  17. 47. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    47. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. MILNER DAM; RIP-RAPPED UPPER SLOPE OF CENTER DAM; CROWD ALONG CHANNEL TO TUNNELS. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  18. 56. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. Photocopy of Photograph (original located in Univ. of Denver collection) C.R. Savage, Photographer, March, 1905. MILNER DAM SPILLWAY AND GATES; BATTERY OF REGULATING GATES FROM DOWNSTREAM SIDE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  19. 87. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    87. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, date unknown. ROCK CREEK SIPHON, LOW LINE CANAL, TWIN FALLS COUNTY, SOUTH OF KIMBERLY, IDAHO; UPPER END OF THE SIPHON. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  20. 84. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    84. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, date unknown. ROCK CREEK SIPHON, TWIN FALLS COUNTY, SOUTH OF KIMBERLY, IDAHO; WEST VIEW OF SIPHON PIPE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  1. 85. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    85. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, date unknown. ROCK CREEK SIPHON, TWIN FALLS COUNTY, SOUTH OF KIMBERLY, IDAHO; EAST VIEW OF SIPHON PIPE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  2. 86. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    86. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, date unknown. ROCK CREEK SIPHON, TWIN FALLS COUNTY, SOUTH OF KIMBERLY, IDAHO; MEN WORKING ON THE EAST END OF THE SIPHON. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  3. 82. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    82. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, date unknown. DRY CREEK HEADGATES, TWIN FALLS COUNTY, SOUTH OF MURTAUGH, IDAHO; CHECK GATES ACROSS THE MAIN CANAL BELOW DRY CREEK. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  4. 83. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    83. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, date unknown. DRY CREEK GATES, TWIN FALLS COUNTY, SOUTH OF MURTAUGH, IDAHO; GATES FROM THE LOWER SIDE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  5. 75. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    75. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. SNAKE RIVER GOING DRY AT MILNER. POWER DITCH AT RIGHT; RIVER IN POOLS FOLLOWING GATE CLOSURE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  6. 59. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    59. Photocopy of Photograph (original located in Univ. of Denver collection) C.R. Savage, Photographer, date unknown. MILNER DAM; TUNNEL OUTLETS WITH SNAKE RIVER PASSING THROUGH. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  7. 45. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    45. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March 1905. SNAKE RIVER BEHIND MILNER DAM; MILNER RESERVOIR RISING. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  8. 70. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    70. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. SNAKE RIVER SHALLOWS AFTER TUNNEL CLOSURE; DOWNSTREAM FROM MILNER DAM. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  9. 66. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    66. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. MILNER DAM. CURRENT APPROACHING GATES, UPSTREAM. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  10. 52. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    52. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. MILNER TUNNEL CLOSURE GATES AND GROUP. GROUP ON GATE PLATFORM JUST BEFORE LOWERING GATES. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  11. 43. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    43. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. NORTH SIDE CANAL GATES, PART OF ORIGINAL PROJECT. CLOSE-UP OF NORTH CANAL GATES. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  12. 80. Photocopy of Photograph (original located in Univ. of Denver ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    80. Photocopy of Photograph (original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. WASTE GATES ON MAIN CANAL. F.H. BUHL OVERLOOKS THE NEWLY OPENED CANAL AT GATES ONE MILE BELOW DAM. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  13. A Needs Assessment for the Introduction of a Food Science Program at the Univ. of Guyana

    ERIC Educational Resources Information Center

    Morrison, Donna

    2012-01-01

    This research describes the outcome of a needs assessment to determine whether the Univ. of Guyana should introduce a Food Science program. The research design utilized interviews and questionnaires to large manufacturing organizations and agroprocessors to determine if the required skills are available for the manufacturing process. Results…

  14. A Needs Assessment for the Introduction of a Food Science Program at the Univ. of Guyana

    ERIC Educational Resources Information Center

    Morrison, Donna

    2012-01-01

    This research describes the outcome of a needs assessment to determine whether the Univ. of Guyana should introduce a Food Science program. The research design utilized interviews and questionnaires to large manufacturing organizations and agroprocessors to determine if the required skills are available for the manufacturing process. Results…

  15. 37. Photocopy of Photograph(original located in Univ. of Denver collection). ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    37. Photocopy of Photograph(original located in Univ. of Denver collection). C.R. Savage, Photographer, March, 1905. NORTH AND MIDDLE DAMS, MILNER DAM, MAIN CHANNEL DAM, FOREGROUND; MIDDLE DAM AND TUNNEL REGULATORS, BACKGROUND. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  16. AO operations at Gemini South

    NASA Astrophysics Data System (ADS)

    Marin, Eduardo; Cardwell, Andrew; Pessev, Peter

    2014-08-01

    The 8m Gemini South telescope is entering an exciting new era of AO operations, which put it at the forefront of astronomical AO in terms of both wide field AO, and extreme-AO systems. Major milestones achieved were the successful commissioning of GeMS, in 2012, and GPI, in late 2013 and early 2014. Currently we are operating two of the worlds most advanced astronomical AO systems. Gemini, running primarily in queue, must balance the promise of AO with the demands of the community to use non-AO instruments. We discuss the current state of the two AO systems, and their operational models. The preparations that go into planning each AO run, the difficulties in scheduling around non-AO instruments, and the differences between scheduling LGS AO and non-LGS AO are discussed.

  17. Multirate LQG AO control

    NASA Astrophysics Data System (ADS)

    Raynaud, H. F.; Kulcsár, C.; Correia da Silva, C.; Conan, J. M.

    2008-07-01

    All thing being equal, increasing the sampling rate of a computer-controlled feedback loop extends its effective bandwidth, and thus the achievable performance in terms of disturbance rejection. This applies to AO systems, where deformable mirror's (DM) control voltages are computed from wavefront sensor's (WFS) measurements. However, faster sampling, i.e. shorter exposure time for the WFS's CCD, results (especially for low-flux astronomical applications) in higher measurement noise, thereby degrading overall performance. A way to circumvent this limitation is to increase only the DM's control rate. However, standard integral AO control is inherently ill-suited for such multirate mode, because integrators require an uninterrupted measurement stream to maintain closed-loop stability. On the other hand, Linear Quadratic Gaussian (LQG) AO control, where DM controls are computed from explicit predictions of future values of the turbulent phase provided by a Kalman filter, can be easily adapted to multirate configurations where the WFS sampling period is a multiple of the DM's one, provided that a stochastic model of the turbulent phase at the fast (DM) rate is available. The Kalman filter, between two successive measurements, operates in (observer) open-loop mode, with predictions updated by extrapolating current trends in the turbulent phase's trajectory. Thus, while simple vector-valued AR(1) turbulence models are sufficient for single-rate LQG AO loops, more complex stochastic models are likely to be needed to achieve good performance in multirate configurations.

  18. Univers: The construction of an internet-wide descriptive naming system

    NASA Technical Reports Server (NTRS)

    Bowman, C. Mic

    1990-01-01

    Descriptive naming systems allow clients to identify a set of objects by description. Described here is the construction of a descriptive naming system, called Univers, based on a model in which clients provide both an object description and some meta-information. The meta-information describes beliefs about the query and the naming system. Specifically, it is an ordering on a set of perfect world approximations, and it describes the preferred methods for accommodating imperfect information. The description is then resolved in a way that respects the preferred approximations.

  19. Centre d'Observacio de l'Univers: first year of activities

    NASA Astrophysics Data System (ADS)

    Ribas, S. J.

    2011-11-01

    The Centre d'Observacio de l'Univers is one of the parts of the Parc Astronomic Montsec (PAM). PAM is an initiative of the Catalan government, through the Consorci del Montsec (Montsec Consortium), to take advantage of the capabilities and potential of the Montsec region to develop scientific research, training, and outreach activities, particularly in the field of astronomy. The choice of the Montsec mountains to install the PAM was motivated by the magnificent conditions for observing the sky at night; the sky above Montsec is the best (natural sky free of light pollution) in Catalonia for astronomical observations. The PAM has two main parts: the Observatori Astronomic del Montsec (OAdM) and the Centre d'Observacio del'Univers (COU). The OAdM is a professional observatory with an 80 cm catadioptric telescope (Joan Oro Telescope). The COU is a large multipurpose center which is intended to become an educational benchmark for teaching and communicate astronomy and other sciences in Catalonia. Since the opening more than 50000 visitors went to this center to enjoy science with Montsec dark skies and an special natural environment.

  20. AO Group Annual Report

    SciTech Connect

    Olivier, S

    2005-10-04

    The Adaptive Optics (AO) Group in I Division develops and tests a broad range of advanced wavefront control technologies. Current applications focus on: Remote sensing, High power lasers, Astronomy, and Human vision. In the area of remote sensing, the AO Group leads a collaborative effort with LLNL's Nonproliferation, Arms Control & International Security (NAI) Directorate on Enhanced Surveillance Imaging. The ability to detect and identify individual people or vehicles from long-range is an important requirement for proliferation detection and homeland security. High-resolution imaging along horizontal paths through the atmosphere is limited by turbulence, which blurs and distorts the image. For ranges over {approx}one km, visible image resolution can be reduced by over an order of magnitude. We have developed an approach based on speckle imaging that can correct the turbulence-induced blurring and provide high resolution imagery. The system records a series of short exposure images which freeze the atmospheric effects. We can then estimate the image magnitude and phase using a bispectral estimation algorithm which cancels the atmospheric effects while maintaining object information at the diffraction limit of the imaging system.

  1. Transformation en ondelettes et applications en sciences de l'Univers

    NASA Astrophysics Data System (ADS)

    Bijaoui, A.

    2002-03-01

    La transformation en ondelettes est apparue au début des années 1980. Elle permet le déploiement de l'information en échelles. Cette transformation est bien adaptée à l'étude des structures hiérarchisées que nous montrent les images des astres. Elle peut être perçue comme résultant de l'analyse multirésolution, un banc de filtres ou une suite de filtrages passe-bande. Ces trois aspects sont successivement analysés. L'analyse résultante dérive de la notion de coefficients significatifs. Plusieurs types de bruit sont examinés. Diverses applications au traitement et à l'analyse des signaux et des images en sciences de l'univers sont passées en revue: compression des images, réduction du bruit, amélioration de la résolution, synthèse d'ouverture, détection des structures, analyse des signaux, vision multiéchelle et indicateurs statistiques.

  2. Histoire du télescope, la contemplation de l'Univers, des premiers instruments aux actuelles machines célestes

    NASA Astrophysics Data System (ADS)

    Nazé, Yaël

    2009-01-01

    Alors que la plupart des scientifiques réalisent leurs expérimentations en laboratoire, les astronomes sont condamnés à ne jamais pouvoir toucher l'objet de leurs travaux: le ciel se laisse contempler mais demeure hors d'atteinte. Pour déchiffrer le message céleste, l'oeil ne suffit pas. Il fallut attendre la naissance de la première lunette astronomique pour ouvrir une nouvelle voie à notre insatiable désir de savoir. Ancêtre de tous les télescopes petits et grands, ce tout premier instrument d'observation allait en effet étendre vers l'infini le pouvoir de nos yeux. Quatre cents ans après, ce sont d'immenses machines qui scrutent pour nous l'Univers, en nous permettant même de remonter le temps. C'est leur histoire qui nous est racontée ici mais, par deçà les engins les plus complexes, ce livre nous parle de leurs bâtisseurs. Démontant au passage certaines idées reçues, ce livre nous plonge dans les balbutiements de ces instruments avant de nous emmener côtoyer les premiers géants et découvrir les révolutions en cours. Illustré de nombreux documents historiques et techniques, ce récit est également pourvu d'encadrés expliquant en profondeur le fonctionnement des instruments.

  3. Effect of sowing dates and vernalization on Beta vulgaris L. cv. Univers C-leaf structure.

    PubMed

    Sakr, Mohammed M; Almaghrabi, Omar A

    2011-07-01

    This research was conducted to study the effect of three different sowing dates (15th October, 15th November and 15th December) and two vernalization treatments (5 °C and -20 °C) on leaf structure of Beta vulgaris L. cv. Univers. The obtained data are summarized as follows: The maximum values of the most studied parameters; lower epidermis + spongy tissue thickness, midrib, mesophyll tissue, vascular bundle, collenchymatous tissue and number of xylem vessels per arm were found as a result of 15th October sowing date treatment compared with the two other sowing dates. Furthermore, effect of the cooling treatments varied according to the recorded character, sowing date and cooling degree. Most of the vernalization treatments at early sowing dates increased the mesophyll tissue, midrib, number of vascular bundles per transverse section, vascular bundle thickness and number of xylem arms per transverse section. The two studied cooling treatments at 15th October sowing date increased both stomatal index and average number of stomata: average number of epidermis cells compared with the control. Furthermore, 15th October under -20 °C treatment led to small epidermal cells and stomata formation, straight epidermal cell walls and closed stomata in comparison to the control. PMID:23961134

  4. Experiments on the nuclear interactions of pions and electrons. [Dept. of Physics, Univ. of Virginia

    SciTech Connect

    Minehart, R.C.; Ziock, K.O.H.

    1992-08-01

    The analysis of the deuterium content in the CD target used in an experiment to study the [pi] + d [yields] 2p reaction at incident pion energies from 4 to 20 MeV was completed. The final paper describing this experiment will be submitted for publication this summer. Analysis of LAMPF Exp. on pion absorption in [sup 4]He is continuing. In 1991, we collaborated with D. Pocanic from the Univ. of Virginia on a measurement at LAMPF of the [pi][sup 0] production in [pi] + p interactions. This run proved the validity of the method and additional data were obtained in a second run during the summer of 1992, using a new target. Current collaborations at LAMPF include the search for the decay [mu][sup +] [yields] e[sup +] + [gamma](MEGA) and a measurement of the Michel [rho] parameter in the decay [mu] [yields] e + v + v. A U.Va.--PSI collaboration is measuring pion beta decay to an accuracy of less than 1%, using a large acceptance CsI detector to measure the [pi][sup 0] following decay of stopped [pi][sup +] mesons. Most of the U.Va. effort is devoted to the CEBAF Large Acceptance Spectrometer (CLAS) program to the construction of the CLAS forward calorimeter. An apparatus to measure the properties of the scintillators with light from a N[sub 2] laser was built in the spring of 1992. The electronic circuitry for the energy signal from the EGN detector and the circuitry needed to route the signals from the all the photomultipliers to the TDC and ADC circuits are being developed. Experimental proposals for the study of electroproduction of nucleon resonances at CEBAF, including measurements with polarized beam and targets, are being developed.

  5. MEMS AO for Planet Finding

    NASA Technical Reports Server (NTRS)

    Rao, Shanti; Wallace, J. Kent; Shao, Mike; Schmidtlin, Edouard; Levine, B. Martin; Samuele, Rocco; Lane, Benjamin; Chakrabarti, Supriya; Cook, Timothy; Hicks, Brian; Jung, Paul

    2008-01-01

    This slide presentation reviews a method for planet finding using microelectromechanical systems (MEMS) Adaptive Optics (AO). The use of a deformable mirror (DM) is described as a part of the instrument that was designed with a nulling interferometer. The strategy that is used is described in detail.

  6. Pushing AO to Smaller Asteroids

    NASA Astrophysics Data System (ADS)

    Drummond, Jack; Merline, William; Conrad, Al; Dumas, Christophe; Christou, Julian; Carry, Benoit

    2008-08-01

    We have demonstrated that AO imaging can determine the pole and dimensions in 1 or 2 nights on a single target, rather than the years of observations with typical lightcurve inversion techniques that only yield poles and axial ratios, not true dimensions. Now we propose to use NGS AO to measure the triaxial dimensions, shapes, and pole directions (spin vectors) for 6 smaller asteroids that are favorably placed around Dec 1, 2008. Accurately determining the volume from the triaxial dimensions allows us to contribute to calculating densities to much greater precision than currently known. Our work requires observations spanning most of a full rotation period for these 6 objects, which are typically several hours (one has a 27 hr period), and all can be phased sufficiently over two nights. Our primary goal is full rotational coverage in a single filter (K, or H if conditions dictate). Secondary goals, if time and conditions permit, are searching for color variations on the parent asteroids with additional filters and satellite detections/searches with longer exposures. Just 3 days before this proposal deadline, we discovered a satellite this way. See next section. We request two nights on Keck so that in addition to our basic goal of following the asteroids' rotation to find sizes and poles, we can also attempt to implement our secondary goals of multicolor observations and/or satellite searches. If not granted Keck time, then queue observing on Geminii would satisfy our basic goal.

  7. Aerosol Observing System (AOS) Handbook

    SciTech Connect

    Jefferson, A

    2011-01-17

    The Aerosol Observing System (AOS) is a suite of in situ surface measurements of aerosol optical and cloud-forming properties. The instruments measure aerosol properties that influence the earth’s radiative balance. The primary optical measurements are those of the aerosol scattering and absorption coefficients as a function of particle size and radiation wavelength and cloud condensation nuclei (CCN) measurements as a function of percent supersaturation. Additional measurements include those of the particle number concentration and scattering hygroscopic growth. Aerosol optical measurements are useful for calculating parameters used in radiative forcing calculations such as the aerosol single-scattering albedo, asymmetry parameter, mass scattering efficiency, and hygroscopic growth. CCN measurements are important in cloud microphysical models to predict droplet formation.

  8. Experimental study on the thorium-loaded accelerator-driven system at the Kyoto Univ. critical assembly

    SciTech Connect

    Pyeon, C. H.; Yagi, T.; Lim, J. Y.; Misawa, T.

    2012-07-01

    The experimental study on the thorium-loaded accelerator-driven system (ADS) is conducted in the Kyoto Univ. Critical Assembly (KUCA). The experiments are carried out in both the critical and subcritical states for attaining the reaction rates of the thorium capture and fission reactions. In the critical system, the thorium plate irradiation experiment is carried out for the thorium capture and fission reactions. From the results of the measurements, the thorium fission reactions are obtained apparently in the critical system, and the C/E values of reaction rates show the accuracy of relative difference of about 30%. In the ADS experiments with 14 MeV neutrons and 100 MeV protons, the subcritical experiments are carried out in the thorium-loaded cores to obtain the capture reaction rates through the measurements of {sup 115}In(n, {gamma}){sup 116m}In reactions. The results of the experiments reveal the difference between the reaction rate distributions for the change in not only the neutron spectrum but also the external neutron source. The comparison between the measured and calculated reaction rate distributions demonstrates a discrepancy of the accuracy of reaction rate analyses of thorium capture reactions through the thorium-loaded ADS experiments with 14 MeV neutrons. Hereafter, kinetic experiments are planned to be carried out to deduce the delayed neutron decay constants and subcriticality using the pulsed neutron method. (authors)

  9. ATST and Solar AO state of art

    NASA Astrophysics Data System (ADS)

    Rimmele, Thomas; Woeger, Friedrich; Marino, Jose

    2013-12-01

    The 4 meter aperture Advanced Technology Solar Telescope (ATST) is an ELT for solar astronomy, and as such will address a broad range of science questions that require its AO system to operate in several different observing scenarios. We review the science drivers that lead to the most demanding ATST AO system requirements, such as high Strehl ratios at visible wavelengths, MCAO correction, and photon starved, extended FOV wavefront sensing using large, faint structures at the limb of the Sun. Within the context of exisiting high-order AO systems for solar telescopes we present an overview over the current ATST AO system design and capabilities. Finally, we will describe the widely used post-facto image processing techniques of AO corrected solar imaging and spectroscopic data that are required to achieve the desired spatial resolution especially at the short end (380 nm) of the visible spectrum over ATST's full FOV. We will lay out how these techniques will be supported in the AO system to help ATST achieve its scientific goals.

  10. Next generation AO system of Subaru Telescope

    NASA Astrophysics Data System (ADS)

    Hayano, Y.

    2011-09-01

    A laser guide star adaptive optics system with 188 elements is under commissioning at Subaru Telescope. The system has been opened to every astronomer with risk from July, 2011. In parallel, we have started a conceptual study of the next generation AO system for Subaru Telescope. Based on the analysis of the line-up of other instruments at Subaru Telescope, such as Hyper Supreme Camera and Prime Focus Spectrograph, the wide coverage of field of view is the most important characteristics for our next generation AO system. Secondly, a wide field AO at 8-m class telescope will be still competitive at the era of extreme large telescopes. A conceptual study of a ground-layer AO and multi-object AO at Subaru Telescope is introduced in this presentation. It includes performance simulation of both GLAO and MOAO with Subaru Telescope and expected gain in sensitivity and angular resolution for various astronomical targets. Instruments, which match well to a wide field AO system, in infrared wavelength are introduced as well.

  11. The Magellan Telescope adaptive secondary AO system

    NASA Astrophysics Data System (ADS)

    Close, Laird M.; Gasho, Victor; Kopon, Derek; Hinz, Phil M.; Hoffmann, William F.; Uomoto, Alan; Hare, Tyson

    2008-07-01

    The Magellan Clay telescope is a 6.5m Gregorian telescope located in southern Chile at Las Campanas Observatory. The Gregorian design allows for an adaptive secondary mirror that can be tested off-sky in a straight-forward manner. We have fabricated a 85 cm diameter aspheric adaptive secondary with our subcontractors and partners. This secondary has 585 actuators with <1 msec response times. The chopping adaptive secondary will allow low emissivity AO science. We will achieve very high Strehls (~98%) in the Mid-IR AO (8-26 microns) with the BLINC/MIRAC4 Mid-IR science camera. This will allow the first "super-resolution" and nulling Mid-IR studies of dusty southern objects. We will employ a high order (585 mode) pyramid wavefront sensor similar to that used in the Large Binocular Telescope AO systems. The relatively high actuator count will allow modest Strehls to be obtained in the visible (~0.8?m). Our visible light AO (Vis AO) science camera is fed by an advanced ADC and beamsplitter piggy-backed on the WFS optical table. The system science and performance requirements, and an overview the design, interface and schedule for the Magellan AO system are presented here.

  12. Into the blue: AO science with MagAO in the visible

    NASA Astrophysics Data System (ADS)

    Close, Laird M.; Males, Jared R.; Follette, Katherine B.; Hinz, Phil; Morzinski, Katie; Wu, Ya-Lin; Kopon, Derek; Riccardi, Armando; Esposito, Simone; Puglisi, Alfio; Pinna, Enrico; Xompero, Marco; Briguglio, Runa; Quiros-Pacheco, Fernando

    2014-08-01

    We review astronomical results in the visible (λ<1μm) with adaptive optics. Other than a brief period in the early 1990s, there has been little astronomical science done in the visible with AO until recently. The most productive visible AO system to date is our 6.5m Magellan telescope AO system (MagAO). MagAO is an advanced Adaptive Secondary system at the Magellan 6.5m in Chile. This secondary has 585 actuators with < 1 msec response times (0.7 ms typically). We use a pyramid wavefront sensor. The relatively small actuator pitch (~23 cm/subap) allows moderate Strehls to be obtained in the visible (0.63-1.05 microns). We use a CCD AO science camera called "VisAO". On-sky long exposures (60s) achieve <30mas resolutions, 30% Strehls at 0.62 microns (r') with the VisAO camera in 0.5" seeing with bright R < 8 mag stars. These relatively high visible wavelength Strehls are made possible by our powerful combination of a next generation ASM and a Pyramid WFS with 378 controlled modes and 1000 Hz loop frequency. We'll review the key steps to having good performance in the visible and review the exciting new AO visible science opportunities and refereed publications in both broad-band (r,i,z,Y) and at Halpha for exoplanets, protoplanetary disks, young stars, and emission line jets. These examples highlight the power of visible AO to probe circumstellar regions/spatial resolutions that would otherwise require much larger diameter telescopes with classical infrared AO cameras.

  13. Adaptive optics (AO) and ground-layer AO for Dome C: numerical simulation results

    NASA Astrophysics Data System (ADS)

    Carbillet, M.; Maire, A.-L.; Le Roux, B.; Aristidi, E.; Giordano, C.; Pasqueron de Fommervault, O.; Gautier, J.; Trinquet, H.

    We present the latest results of our on-going closed-loop “end-to-end” numerical adaptive optics (AO) simulations concerning both a standard-AO and a three-star ground-layer AO system for a near-infrared 2-m class telescope at Dome C, Antarctica. We demonstrate that Dome C is an ideal site for wide-field AO-aided astronomy, define in details the AO system(s) optimized for the median turbulence profile considered, and finally show that a 0.3 Strehl ratio and 200-mas-wide stable point-spread function is reached in band J on at least a 15^prime-diameter field.

  14. Characterization of an AO-OCT system

    SciTech Connect

    Evans, J W; Zawadzki, R J; Jones, S; Olivier, S; Werner, J S

    2007-07-26

    Adaptive optics (AO) and optical coherence tomography (OCT) are powerful imaging modalities that, when combined, can provide high-volumetric-resolution, images of the retina. The AO-OCT system at UC Davis has been under development for 2 years and has demonstrated the utility of this technology for microscopic, volumetric, in vivo retinal imaging [1]. The current system uses an AOptix bimorph deformable mirror (DM) for low-order, high-stroke correction [2] and a 140-actuator Boston Micromachines DM for high-order correction [3]. We are beginning to investigate the potential for increasing the image contrast in this system using higher-order wavefront correction. The first step in this analysis is to quantify the residual wavefront error (WFE) in the current system. Developing an error budget is a common tool for improved performance and system design in astronomical AO systems [4, 5]. The process for vision science systems is also discussed in several texts e.g. [6], but results from this type of analysis have rarely been included in journal articles on AO for vision science. Careful characterization of the AO system will lead to improved performance and inform the design of a future high-contrast system. In general, an AO system error budget must include an analysis of three categories of residual WFE: errors in measuring the phase, errors caused by limitations of the DM(s), and errors introduced by temporal variation. Understanding the mechanisms and relative size of these errors is critical to improving system performance. In this paper we discuss the techniques for characterizing these error sources in the AO-OCT system. It is useful to first calculate an error budget for the simpler case using a model eye, and then add the additional errors introduced for the case of a human subject. Measurement error includes calibration error, wavefront sensor (WFS) CCD noise, and sampling errors. Calibration errors must be measured by an external system. Typically this error is inferred from measurements of the point spread function (PSF). It can also be estimated by measuring known wavefront errors and comparing to the WFS measurement. Both methods will be used in the AO-OCT system. In this particular system measurement error introduced by the WFS can be caused by low light levels, poor camera sensitivity at the operating wavelength and noise introduced by heat in the uncooled CCD. Also, the gaussian beam profile of the system causes centroids near the edges of the pupil to be dimmer, and thus noisier. The easiest way to estimate measurement error is to compare successive wavefront measurements when the system is stable. This techniques will include vibrations and other systematic errors. Alternatively the measurement error can be estimated from measured signal to noise. This is more complicated but will decouple measurement errors from stability measurements. Ultimately, even if the phase is measured perfectly, performance will still be limited by the fitting error [7]. This error is inversely proportional to the number of actuators of the DM. Basically wavefront errors with spatial frequencies greater than half the number of actuators across the aperture cannot be corrected. For DMs with modal influence functions (like the AOptix Bimorph in the AO-OCT system), this translates to the number of modes which can be corrected. The AO-OCT system over-samples the wavefront, so to some extent, we can measure these out-of-band errors directly. In addition to fitting error, the DM will introduce errors based on the ability of each individual actuator to go to the position demanded by the control system. Generally this voltage step size is limited by the resolution of the drive electronics and can be calculated analytically.

  15. MEMS DM development at Iris AO, Inc.

    NASA Astrophysics Data System (ADS)

    Helmbrecht, Michael A.; He, Min; Kempf, Carl J.; Besse, Marc

    2011-03-01

    Iris AO is actively developing piston-tip-tilt (PTT) segmented MEMS deformable mirrors (DM) and adaptive optics (AO) controllers for these DMs. This paper discusses ongoing research at Iris AO that has advanced the state-of-the-art of these devices and systems over the past year. Improvements made to open-loop operation and mirror fabrication enables mirrors to open-loop flatten to 4 nm rms. Additional testing of an anti snap-in technology was conducted and demonstrates that the technology can withstand 100 million snap-in events without failure. Deformable mirrors with dielectric coatings are shown that are capable of handling 630 W/cm2 of incident laser power. Over a localized region on the segment, the dielectric coatings can withstand 100kW/cm2 incident laser power for 30 minutes. Results from the first-ever batch of PTT489 DMs that were shipped to pilot customers are reported. Optimizations made to the open-loop PTT controller are shown to have latencies of 157.5 ?s and synchronous array update rates of nearly 6.5 kHz. Finally, plans for the design and fabrication of the next-generation PTT939 DM are presented.

  16. Experimental comparison of Wide Field AO control schemes using the Homer AO bench.

    NASA Astrophysics Data System (ADS)

    Parisot, Amélie; Petit, Cyril; Fusco, Thierry

    2011-09-01

    Wide Field Adaptive Optics (WFAO) concepts, such as Laser Tomography AO (LTAO) or Multi-Conjugate AO (MCAO) have been developed in order to overcome the anisoplanatism limit of classical AO. Most of the future AO-assisted instruments of ELTs rely on such concepts which have raised critical challenges such as tomographic estimation and from laser and natural guide star combined with efficient DM(s) control. In that context, the experimental validation of the various clever control solutions proposed by several teams in the past years is now essential to reach a level of maturity compatible with their implementation in future WFAO developments for ELT. The ONERA wide field AO facility (HOMER bench) has been developed for these very issues. Gathering a 3D turbulence generator, laser and natural guide stars, two deformable mirrors with variable altitude positions and a PC-based flexible and user-friendly RTC , HOMER allows the implementation and comparison of control schemes from the simplest least-square to the optimal Linear Quadratic Gaussian solutions including Virtual DM and Pseudo-closed loop approaches. After a description of the bench internal calibrations and ultimate performance, all the control schemes are compared experimentally. Their evolutions as a function of wavefront sensors SNR as well as their robustness to calibration / model errors are particularly emphasised. Finally, we derive from the previous works some specific calibrations and identifications procedures ensuring both robustness and efficiency of WFAO systems and we extrapolate their applications to the future ELT AO systems.

  17. Into the Blue: AO Science in the Visible with MagAO

    NASA Astrophysics Data System (ADS)

    Close, Laird; Males, Jared; Morzinski, Katie; Kopon, Derek; Follette, Kate; Rodigas, Timothy; Hinz, Philip; Wu, Ya-Lin; Puglisi, Alfio; Esposito, Simone; Riccardi, Armando; Pinna, Enrico; Xompero, Marco; Briguglio, Runa; Uomoto, Alan; Hare, Tison

    2013-12-01

    The Magellan Clay telescope is a 6.5m Gregorian telescope located in Chile at Las Campanas Observatory. We have fabricated an 85 cm diameter aspheric adaptive secondary with our subcontractors and partners, MagAO passed acceptance tests in spring 2012, and the entire System was commissioned from Nov 17 to Dec 7, 2012. This secondary has 585 actuators with < 1 msec response times (0.7 ms typically). We fabricated a high order (585 mode) pyramid wavefront sensor (similar to that of LBT's FLAO). The relatively high actuator count allows moderate Strehls to be obtained in the visible (0.63-1.05 microns). We have built an CCD science camera called "jVisAO". On-sky long exposures (60s) achieve 30% Strehls at 0.62 microns (r') with the VisAO camera in 0.5" seeing with bright R < 8 mag stars. These relatively high optical wavelength Strehls are made possible by our powerful combination of a next generation ASM and a Pyramid WFS with 200-400 controlled modes and 1000 Hz loop frequencies. To minimize non-common path errors and enable visible AO the VisAO science camera is fed by an advanced triplet ADC and is piggy-backed on the WFS optical board itself. Despite the ability to make 25 mas images we still have ~4 mas of resolution loss to residual vibrations. We will discuss what the most difficult aspects are for visible AO on ELTs scaling from our experience with MagAO.

  18. Diferentes Metodologias Aplicadas ao Ensino de Astronomia

    NASA Astrophysics Data System (ADS)

    Albrecht, E.; Voelzke, M. R.

    2007-08-01

    Espera-se que o educando ao final da educação básica, adquira uma compreensão atualizada das hipóteses, modelos e formas de investigação sobre a origem e evolução do Universo em que vive. O presente trabalho tem como principal objetivo compreender dentre três práticas pedagógicas adotadas no Ensino de Astronomia, na terceira série do Ensino Médio, da Escola Estadual Colônia dos Pescadores, qual melhor cumpre o papel de formação e aprendizagem para vida. A pesquisa preliminar foi através de um questionário onde o intuito foi diagnosticar o conhecimento já existente acerca do tema em questão. O questionário é composto de vinte questões dissertativas e objetivas, onde os educandos das três turmas envolvidas o responderam. Este trabalho utiliza as seguintes metodologias: a tradicional, onde o professor é um repassador de informações, fazendo uso exclusivo de lousa e giz; a segunda também de forma tradicional, porém com auxílio de multimídia para desenvolvimento das aulas e aterceira sob forma de seminários, elaborados e apresentados pelos educandos, no qual o educador faz apenas as intervenções necessárias. Ao final do trabalho os alunos responderão novamente o questionário inicial para diagnosticar dentre as três metodologias utilizadas qual apresentou melhor resultado. Os resultados preliminares obtidos, já podem ser observados e, dos 119 alunos entrevistados, as respostas obtidas são as mais diversas e evidenciam que a grande maioria nunca teve em sua vida escolar o tema Astronomia. Ao serem questionados se já haviam estudado Astronomia as respostas foram: turma A: sim 43%; turma B: sim: 21%; turma C: sim: 24%. Porém quando questionados a respeito do significado de Astronomia observou-se que: turma A: 100% de acertos; turma B: 64% acertos; turma C: 84% de acertos, demonstrando claramente a aprendizagem em diferentes esferas, não dependendo unicamente da escola. Até o presente momento, verificou-se que há interesse em estudar o tema Astronom! ia entre os educandos.

  19. On-sky speckle nulling with the Subaru Coronagraphic Extreme AO (SCExAO) instrument

    NASA Astrophysics Data System (ADS)

    Martinache, Frantz; Guyon, Olivier; Jovanovic, Nemanja; Clergeon, Christophe; Singh, Garima; Kudo, Tomoyuki

    2014-08-01

    Contrast limit for the direct imaging of extrasolar planets from ground based adaptive optics (AO) observations is set by the presence of static and slow-varying aberrations in the optical path that lead to the science instrument. To complement the otherwise highly successful angular differential imaging (ADI) technique toward small angular separation, we propose to employ additional wavefront control to modulate the diffraction. This flexible approach introduces enough diversity to discriminate genuine structures of the observed target from spurious diffraction features in the image. One possible implementation of such form of coherence differential imaging (CDI) is a speckle nulling algorithm that iteratively suppresses diffraction features inside a region constrained by the number of active elements of the deformable mirror modulating the wavefront, and the coronagraph. This paper presents on-sky results obtained with this approach, on the Subaru Coronagraphic Extreme AO (SCExAO) instrument.

  20. The Magellan Telescope Adaptive Secondary AO System: a visible and mid-IR AO facility

    NASA Astrophysics Data System (ADS)

    Close, Laird M.; Gasho, Victor; Kopon, Derek; Males, Jared; Follette, Katherine B.; Brutlag, Kevin; Uomoto, Alan; Hare, Tyson

    2010-07-01

    The Magellan Clay telescope is a 6.5m Gregorian telescope located in Chile at Las Campanas Observatory. The Gregorian design allows for an adaptive secondary mirror that can be tested off-sky in a straightforward manner. We have fabricated a 85 cm diameter aspheric adaptive secondary with our subcontractors and partners, the ASM passed acceptance tests in July 2010. This secondary has 585 actuators with <1 msec response times (0.7 ms typically). This adaptive secondary will allow low emissivity AO science. We will achieve very high Strehls (~98%) in the Mid-IR (3-26 microns) with the BLINC/MIRAC4 Mid-IR science camera. This will allow the first "super-resolution" and nulling Mid-IR studies of dusty southern objects. We will employ a high order (585 mode) pyramid wavefront sensor similar to that now successfully used at the Large Binocular Telescope. The relatively high actuator count will allow modest Strehls to be obtained in the visible (0.63-1.05 ?m). Moderate (~20%) Strehls have already been obtained at 0.8 ?m at the LBT with the same powerful combination of a next generation ASM and Pyramid WFS as we are providing for Magellan. Our visible light AO (VisAO) science camera is fed by an advanced triplet ADC and is piggy-backed on the WFS optical board. We have designed an additional "clean-up" very fast (2 kHz) tilt stabilization system for VisAO. Also a high-speed shutter will be used to block periods of poor correction. The VisAO facility can be reconfigured to feed an optical IFU spectrograph with 20 mas spaxels. The entire system passed CDR in June 2009, and is now finished the fabrication phase and is entering the integration phase. The system science and performance requirements, and an overview the design, interface and schedule for the Magellan AO system are presented here.

  1. Results of AO simulations for ELTs

    NASA Astrophysics Data System (ADS)

    Conan, Rodolphe; Le Louarn, Miska; Braud, J.; Fedrigo, Enrico; Hubin, Norbert N.

    2003-01-01

    The design and elaboration of Extremely Large Telescopes (ELT) with primary mirror from 20m to 100m face with many challenges: mechanical, optical, computational, etc. To benefit completely of the full potentiality of such facilities, an Adaptive Optics System (AOS) have also to be designed for these telescopes. For whole field--of--view compensation and full sky coverage, the new but promising Multi--Conjugated Adaptive Optics (MCAO) technique has to be envisaged. The first step towards the design of an MCAO system is the numerical simulation. This is the first challenge we have to face. The scale of AO simulations being imposed by the ratio (D/r0), the simulation requirements of a MCAOS for an ELT, in terms of computing power and memory available to store the data, reach and sometimes overcome the capacity of actual computers. In ESO, we have evaluated different hardware and software strategies to achieve MCAO simulations goals. Two codes have been developed to simulate MCAOS using an analytical and an end-to-end model. The goals and advantages/limitations of both approaches is shown. The hardware requirements for both methods is also given through the size of their largest matrices. And finally, results of hardware and software tests for MCAO simulations with PC--cluster and paralleled code are presented.

  2. LGS-AO Imaging of Every Kepler Planet Candidate: the Robo-AO KOI Survey

    NASA Astrophysics Data System (ADS)

    Baranec, Christoph; Law, Nicholas; Morton, Timothy; Ziegler, Carl; Nofi, Larissa; Atkinson, Dani; Riddle, Reed

    2015-12-01

    The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging, to search for blended nearby stars which may be physically associated companions and/or responsible for transit false positives. We will present the results from searching for companions around over 3,000 Kepler planet hosts in 2012-2015. We will describe our first data release covering 715 planet candidate hosts, and give a preview of ongoing results including improved statistics on the likelihood of false positive planet detections in the Kepler dataset, many new planets in multiple star systems, and new exotic multiple star systems containing Kepler planets. We will also describe the automated Robo-AO survey data reduction methods, including a method of using the large ensemble of target observations as mutual point-spread-function references, along with a new automated companion-detection algorithm designed for extremely large adaptive optics surveys. Our first data release covered 715 objects, searching for companions from 0.15” to 2.5” separation with contrast up to 6 magnitudes. We measured the overall nearby-star-probability for Kepler planet candidates to be 7.4+/-1.0%, and we will detail the variations in this number with stellar host parameters. We will also discuss plans to extend the survey to other transiting planet missions such as K2 and TESS as Robo-AO is in the process of being re-deployed to the 2.1-m telescope at Kitt Peak for 3 years and a higher-contrast Robo-AO system is being developed for the 2.2-m UH telescope on Maunakea.

  3. Electromagnetic DM technology meets future AO demands

    NASA Astrophysics Data System (ADS)

    Hamelinck, Roger; Rosielle, Nick; Steinbuch, Maarten; Doelman, Niek

    New deformable mirror technology is developed by the Technische Universiteit Eindhoven, Delft University of Technology and TNO Science and Industry. Several prototype adaptive deformable mirrors are realized mirrors, up to 427 actuators and ∅150mm diameter, with characteristics suitable for future AO systems. The prototypes consist of a 100µm thick, continuous facesheet on which low voltage, electromagnetic, push-pull actuators impose out-of-plane displacements. The variable reluctance actuators with ±10µm stroke and nanometer resolution are located in a standard actuator module. Each module with 61 actuators connects to a single PCB with dedicated, 16 bit, PWM based, drivers. A LVDS multi-drop cable connects up to 32 actuator modules. With the actuator module, accompanying PCB and multi-drop system the deformable mirror technology is made modular in its mechanics and electronics. An Ethernet-LVDS bridge enables any commercial PC to control the mirror using the UDP standard. Latest results of the deformable mirror technology development are presented.

  4. Low-order AO system in LAMOST

    NASA Astrophysics Data System (ADS)

    Yuan, Xiangyan; Cui, Xiangqun; Liu, Genrong; Zhang, Yong; Qi, Yongjun

    2006-06-01

    The large sky area multi-object fiber spectroscopic telescope (LAMOST) is a special reflecting Schmidt telescope with its main optical axis on the meridian plane tilted by an angle of 25° to the horizontal. The clear aperture is 4m, working in optical band. The light path is 60m long when working in observing mode and it will be doubled if work in auto-collimation mode. So the image quality is affected clearly by the ground seeing and the dome seeing. In order to improve the seeing condition of the long light path, we enclosed the spherical primary and the focus unit in a tunnel enclosure and cooled the tunnel. This is an effective but passive method. Corresponding experiments and simulations show the main part of the aberrations caused by the ground seeing and dome seeing is slowly changed low order items such as tip-tilt, defocus, astigmatism, coma and spherical aberration. Thus we plan to develop the low-order AO system based on the low-cost 37-channel OKO deformable mirror for the telescope to better the ground seeing and the dome seeing, not aimed to reach diffraction limited image. This work is being carried on now.

  5. Io's Corona: Asymmetries and AO Observations

    NASA Astrophysics Data System (ADS)

    Schneider, N. M.; Burger, M. H.; Sutton, S. E.; Dubson, M. A.

    2003-05-01

    Io's corona is the critical link between Io's atmosphere and the plasma torus. This region, from the exobase to the Hill sphere at about 6 RIo, has now been studied in enough detail to search for temporal variations, spatial asymmetries, and differences between atomic species. Our mutual eclipse observations reveal a relatively stable sodium corona with a significant asymmetry: Io's sub-Jupiter side is 50% brighter than the anti-Jupiter side (Burger et al., ApJ 563, 2001). We also find that Io's sodium corona falls off more steeply than the oxygen corona (measured by HST, Wolven et al., JGR 106, 2001). This effect exceeds that expected from their different ionization potentials, and is better explained by electron cooling near Io. Despite the promise of coronal studies, observations to date have required either the UV capability of HST or satellite mutual eclipses occurring every six years. We have undertaken an adaptive optics study of sodium in Io's corona to allow more routine diagnostic observations. Standard groundbased imaging suffers from the inevitable blurring of Io's 1.2"-wide disk with the 6" corona, fainter by up to 4 orders of magnitude. AO has the potential of imaging the corona by limiting the blurring of Io's disk. We will report on observations using the Air Force's 3.67m AEOS telescope at Haleakala, Maui, and our efforts to measure coronal emissions through rigorous differencing of on-band and off-band images. This work has been supported by NASA's Planetary Astronomy program and NSF's Advanced Technology and Instrumentation program.

  6. NFIRAOS Multiconjugate AO System for TMT

    NASA Astrophysics Data System (ADS)

    Herriot, Glen; Andersen, David; Atwood, Jenny; Byrnes, Peter; Boyer, Corinne; Caputa, Kris; Correia, Carlos; Dunn, Jennifer; Ellerbroek, Brent; Fitzsimmons, Joeleff; Gilles, Luc; Hickson, Paul; Hill, Alexis; Pazder, John; Reshetov, Vlad; Smith, Malcolm; Véran, Jean-Pierre; Wang, Lianqi; Wevers, Ivan

    2011-09-01

    NFIRAOS, the Adaptive Optics system for the Thirty Meter Telescope, is a Multiconjugate Adaptive Optics System of order 60x60 with two deformable mirrors and six laser guide star wavefront sensors. NFIRAOS is 8 x 10 x 5 m (L x W x H) on a Nasmyth Platform and supports three client instruments operating over 0.8 - 2.5 ?m wavelength range. In this paper we discuss: NFIRAOS' requirements and architecture; changes to NFIRAOS since the last AO4ELT conference; interior details of NFIRAOS; interfaces to instruments; integration and verification plans. Top-level science requirements include 50% sky coverage at the galactic pole with <187 nm wavefront error. Astrometry is an important science driver - to minimize image distortion, we have recently revised the optical design to use four off-axis paraboloidal mirrors. We have vastly simplified the laser WFS zoom optics and moved them inside the cold enclosure. To control image magnification, differential magnification and tip/tilt/focus, NFIRAOS' client instruments have three low-order warfront sensors monitoring near-infrared natural guide stars. These stars are sharpened by NFIRAOS, which assists sky coverage. NFIRAOS will have high throughput and low thermal background - it will be cooled to -30 °C. The insulated walls have a buried cold plate to intercept heat leakage and isothermalize the interior of NFIRAOS. Instruments have stringent requirements on heat leakage and must provide their own rotator and interface to NFIRAOS, including a rotating seal. For wavelength and flat field calibration of client instruments, a NFIRAOS Science Calibration Unit (NSCU) feeds light in the entrance window, through NFIRAOS, to instruments. Inside NFIRAOS are deployable light sources simulating natural and laser guide stars, a focal plane mask with pinholes illuminated by the NSCU, as well as a turbulence phase screen. A prototype screen has been manufactured by magneto-rheological machining. We are currently updating the NFIRAOS preliminary design.

  7. First closed-loop visible AO test results for the advanced adaptive secondary AO system for the Magellan Telescope: MagAO's performance and status

    NASA Astrophysics Data System (ADS)

    Close, Laird M.; Males, Jared R.; Kopon, Derek A.; Gasho, Victor; Follette, Katherine B.; Hinz, Phil; Morzinski, Katie; Uomoto, Alan; Hare, Tyson; Riccardi, Armando; Esposito, Simone; Puglisi, Alfio; Pinna, Enrico; Busoni, Lorenzo; Arcidiacono, Carmelo; Xompero, Marco; Briguglio, Runa; Quiros-Pacheco, Fernando; Argomedo, Javier

    2012-07-01

    The heart of the 6.5 Magellan AO system (MagAO) is a 585 actuator adaptive secondary mirror (ASM) with <1 msec response times (0.7 ms typically). This adaptive secondary will allow low emissivity and high-contrast AO science. We fabricated a high order (561 mode) pyramid wavefront sensor (similar to that now successfully used at the Large Binocular Telescope). The relatively high actuator count (and small projected ~23 cm pitch) allows moderate Strehls to be obtained by MagAO in the “visible” (0.63-1.05 μm). To take advantage of this we have fabricated an AO CCD science camera called "VisAO". Complete “end-to-end” closed-loop lab tests of MagAO achieve a solid, broad-band, 37% Strehl (122 nm rms) at 0.76 μm (i’) with the VisAO camera in 0.8” simulated seeing (13 cm ro at V) with fast 33 mph winds and a 40 m Lo locked on R=8 mag artificial star. These relatively high visible wavelength Strehls are enabled by our powerful combination of a next generation ASM and a Pyramid WFS with 400 controlled modes and 1000 Hz sample speeds (similar to that used successfully on-sky at the LBT). Currently only the VisAO science camera is used for lab testing of MagAO, but this high level of measured performance (122 nm rms) promises even higher Strehls with our IR science cameras. On bright (R=8 mag) stars we should achieve very high Strehls (>70% at H) in the IR with the existing MagAO Clio2 (λ=1-5.3 μm) science camera/coronagraph or even higher (~98% Strehl) the Mid-IR (8-26 microns) with the existing BLINC/MIRAC4 science camera in the future. To eliminate non-common path vibrations, dispersions, and optical errors the VisAO science camera is fed by a common path advanced triplet ADC and is piggy-backed on the Pyramid WFS optical board itself. Also a high-speed shutter can be used to block periods of poor correction. The entire system passed CDR in June 2009, and we finished the closed-loop system level testing phase in December 2011. Final system acceptance (“pre-ship” review) was passed in February 2012. In May 2012 the entire AO system is was successfully shipped to Chile and fully tested/aligned. It is now in storage in the Magellan telescope clean room in anticipation of “First Light” scheduled for December 2012. An overview of the design, attributes, performance, and schedule for the Magellan AO system and its two science cameras are briefly presented here.

  8. AO 0235+164 and Surrounding Field: Surprising HST Results

    NASA Technical Reports Server (NTRS)

    Burbidge, E. M.; Beaver, E. A.; Cohen, Ross D.; Junkkarinen, V. T.; Lyons, R. W.

    1996-01-01

    Results obtained with the Hubble Space Telescope on the highly variable radio, x-ray, and gamma-ray emitting QSO (or BL Lac object) AO 0235 + 164 are presented and analyzed. WFPC2 images were obtained in 1994 June, when AO 0235 + 164 was bright (m approx. 17), and the results are described in Sec. 3. After subtraction of the PSF of the QSO, hereafter called AO following the nomenclature of Yanny et al. (1989), the companion object named A, 2 sec south of AO, is discovered not to be an elliptical galaxy as hypothesized earlier, but to be an AGN object, with a central UV-bright point-source nucleus and faint surrounding nebulosity extending to AO. The second companion object 1.3 sec east of AO discovered by Yanny et al. (1989) and named object Al, appears more like a normal spiral galaxy. We have measured the positions, luminosities, and colors of some 30 faint objects in the field around AO 0235 + 16; most are extended and may be star-forming galaxies in a loose group or cluster. Our most surprising result of the HST observations comes from FOS spectra obtained in 1995 July, discussed in Sec. 4. Because of a positioning error of the telescope and AO's faintness at that time (m approx. 20), object A was observed instead of the intended target AO. Serendipitously, we discovered A to have broad deep BALQSO-type absorptions of C IV, Si IV, N V shortward of broad emissions. A is thus ejecting high velocity, highly ionized gas into the surrounding IGM. We discuss in Sec. 5 the relationship of the objects in the central 10 sec X 1O sec region around AO, where redshifts z(sub e) = 0.94, z(sub a) = 0.524, 0.851 in AO, (sub e) = 0.524 and Z(sub BAL)=0.511 in A, are found. We hypothesize that some of the 30 faint objects in the 77 sec. x 77 sec. field may be part of a large star-forming region at z approx. 0.5, as suggested for a few objects by Yanny et al. (1989). The proximity of two highly active extragalactic objects, AO 0235+164 and its AGN companion A, is remarkable and one of the authors (EMB) suggests it may require consideration of a non-cosmological component of redshift in AO 0235+164.

  9. The Subaru Coronagraphic Extreme AO Project: Progress and Upgrades

    NASA Astrophysics Data System (ADS)

    Jovanovic, Nemanja; Martinache, F.; Guyon, O.; Clergeon, C.; Garrel, V.

    2013-01-01

    The Subaru Coronagraphic Extreme AO (SCExAO) instrument consists of a high performance Phase Induced Amplitude Apodisation (PIAA) coronagraph combined with an extreme Adaptive Optics (AO) system operating in the near-infrared (H band). The extreme AO system driven by the 2000 element deformable mirror will allow for Strehl ratios>90% to be achieved in the H-band when it goes closed loop. This makes the SCExAO instrument a powerful platform for high contrast imaging down to angular separations of the order of 1 ?/D. In this paper we report on the recent progress in regards to the development of the instrument, which includes the addition of a visible bench that makes use of the light at shorter wavelengths not currently utilized by SCExAO and closing the loop on the tip/tilt wavefront sensor. We will also discuss two exciting guest instruments which will expand the capabilities of SCExAO over the next few years; namely CHARIS which is a integral field spectrograph as well as VAMPIRES, a visible aperture masking experiment based on polarimetric analysis of circumstellar disks.

  10. LGS-AO Imaging of Every Kepler Planet Candidate: the Robo-AO KOI Survey

    NASA Astrophysics Data System (ADS)

    Law, Nicholas Michael; Baranec, Christoph; Morton, Timothy; Ziegler, Carl; Atkinson, Dani; Riddle, Reed

    2015-08-01

    The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging, to search for blended nearby stars which may be physically associated companions and/or responsible for transit false positives. We will present the results from searching for companions around over 3,000 Kepler planet hosts in 2012-2015. We will describe our first data release covering 715 planet candidate hosts, and give a preview of ongoing results including improved statistics on the likelihood of false positive planet detections in the Kepler dataset, many new planets in multiple star systems, and new exotic multiple star systems containing Kepler planets.We will also describe the automated Robo-AO survey data reduction methods, including a method of using the large ensemble of target observations as mutual point-spread-function references, along with a new automated companion-detection algorithm designed for extremely large adaptive optics surveys.Our first data release covered 715 objects, searching for companions from 0.15” to 2.5” separation with contrast up to 6 magnitudes. We measured the overall nearby-star-probability for Kepler planet candidates to be 7.4+/-1.0%, and we will detail the variations in this number with stellar host parameters. We will also discuss several KOIs of particular interest, including KOI-191 and KOI-1151, which are both multi-planet systems with detected stellar companions whose unusual planetary system architecture might be best explained if they are ``coincident multiple'' systems, with several transiting planets shared between the two stars. Finally, we will discuss and update the 98%-confidence evidence from our survey that third bodies in star/planet systems produce an excess of close-in giant planets.

  11. The Robo-AO automated intelligent queue system

    NASA Astrophysics Data System (ADS)

    Riddle, Reed L.; Hogstrom, Kristina; Papadopoulos, Athanasios; Baranec, Christoph; Law, Nicholas M.

    2014-07-01

    Robo-AO is the first automated laser adaptive optics instrument. In just its second year of scientific operations, it has completed the largest adaptive optics surveys to date, each comprising thousands of targets. Robo-AO uses a fully automated queue scheduling system that selects targets based on criteria entered on a per observing program or per target basis, and includes the ability to coordinate with US Strategic Command automatically to avoid lasing space assets. This enables Robo-AO to select among thousands of targets at a time, and achieve an average observation rate of approximately 20 targets per hour.

  12. SCExAO: First Results and On-Sky Performance

    NASA Technical Reports Server (NTRS)

    Currie, Thayne; Guyon, Olivier; Martinache, Frantz; Clergeon, Christophe; McElwain, Michael; Thalmann, Christian; Jovanovic, Nemanja; Singh, Garima; Kudo, Tomoyuki

    2013-01-01

    We present new on-sky results for the Subaru Coronagraphic Extreme Adaptive Optics imager (SCExAO) verifying and quantifying the contrast gain enabled by key components: the closed-loop coronagraphic low-order wavefront sensor (CLOWFS) and focal plane wavefront control ("speckle nulling"). SCExAO will soon be coupled with a high-order, Pyramid wavefront sensor which will yield greater than 90% Strehl ratio and enable 10(exp 6) -10(exp 7) contrast at small angular separations allowing us to image gas giant planets at solar system scales. Upcoming instruments like VAMPIRES, FIRST, and CHARIS will expand SCExAO's science capabilities.

  13. SCExAO: First Results and On-Sky Performance

    NASA Astrophysics Data System (ADS)

    Currie, Thayne; Guyon, Olivier; Martinache, Frantz; Clergeon, Christophe; McElwain, Michael; Thalmann, Christian; Jovanovic, Nemanja; Singh, Garima; Kudo, Tomoyuki

    2014-01-01

    We present new on-sky results for the Subaru Coronagraphic Extreme Adaptive Optics imager (SCExAO) verifying and quantifying the contrast gain enabled by key components: the closed-loop coronagraphic low-order wavefront sensor (CLOWFS) and focal plane wavefront control (``speckle nulling''). SCExAO will soon be coupled with a high-order, Pyramid wavefront sensor which will yield > 90% Strehl ratio and enable 106-107 contrast at small angular separations allowing us to image gas giant planets at solar system scales. Upcoming instruments like VAMPIRES, FIRST, and CHARIS will expand SCExAO's science capabilities.

  14. A Tilted-Trough Mechanism for AO/NAO

    NASA Astrophysics Data System (ADS)

    Jin, F.; Kimoto, M.; Watanabe, M.; Pan, L.; Yasutomi, N.

    2001-12-01

    The least damped mode of the linear atmospheric dynamic system with the zonal mean flow interacting with stationary waves is shown to bear much resemblance to the observed Arctic Oscillation (AO)in terms of both zonal and associated stationary wave components. This AO-like mode results from the dynamic self-organization among the components of zonal mean flow and the associated stationary waves through a so-called tilted-trough positive feedback. Namely, the anomalous AO-like sheared zonal flow generates the associated anomaly in stationary waves in such a way that the tilts of the total stationary waves are altered to reinforce the sheared zonal-flow anomaly through the anomalous momentum flux convergence. Thus the AO-like least damped mode, which can be excited by surface or other forcing, is expected to be dominant over monthly and longer time scales.

  15. Beyond the Blur: Construction and Characterization of the First Autonomous AO System, and, An AO Survey of Magnetar Proper Motions

    NASA Astrophysics Data System (ADS)

    Tendulkar, Shriharsh Prakash

    Adaptive optics (AO) corrects distortions created by atmospheric turbulence and delivers diffraction-limited images on ground-based telescopes. The vastly improved spatial resolution and sensitivity has been utilized for studying everything from the magnetic fields of sunspots upto the internal dynamics of high-redshift galaxies. This thesis about AO science from small and large telescopes is divided into two parts: Robo-AO and magnetar kinematics. In the first part, I discuss the construction and performance of the world's first fully autonomous visible light AO system, Robo-AO, at the Palomar 60-inch telescope. Robo-AO operates extremely efficiently with an overhead < 50s, typically observing about 22 targets every hour. We have performed large AO programs observing a total of over 7,500 targets since May 2012. In the visible band, the images have a Strehl ratio of about 10% and achieve a contrast of upto 6 magnitudes at a separation of 1‧‧. The full-width at half maximum achieved is 110-130 milli-arcsecond. I describe how Robo-AO is used to constrain the evolutionary models of low-mass pre-main-sequence stars by measuring resolved spectral energy distributions of stellar multiples in the visible band, more than doubling the current sample. I conclude this part with a discussion of possible future improvements to the Robo-AO system. In the second part, I describe a study of magnetar kinematics using high-resolution near-infrared (NIR) AO imaging from the 10-meter Keck II telescope. Measuring the proper motions of five magnetars with a precision of upto 0.7 milli-arcsecond/yr -1, we have more than tripled the previously known sample of magnetar proper motions and proved that magnetar kinematics are equivalent to those of radio pulsars. We conclusively showed that SGR 1900+14 and SGR 1806-20 were ejected from the stellar clusters with which they were traditionally associated. The inferred kinematic ages of these two magnetars are 6 +/- 1.8 kyr and 650 +/-3 00 yr respectively. These ages are a factor of three to four times greater than their respective characteristic ages. The calculated braking index is close to unity as compared to three for the vacuum dipole model and 2.5--2.8 as measured for young pulsars. I conclude this section by describing a search for NIR counterparts of new magnetars and a future promise of polarimetric investigation of a magnetars' NIR emission mechanism.

  16. Second generation Robo-AO instruments and systems

    NASA Astrophysics Data System (ADS)

    Baranec, Christoph; Riddle, Reed; Law, Nicholas M.; Chun, Mark R.; Lu, Jessica R.; Connelley, Michael S.; Hall, Donald; Atkinson, Dani; Jacobson, Shane

    2014-07-01

    The prototype Robo-AO system at the Palomar Observatory 1.5-m telescope is the world's first fully automated laser adaptive optics instrument. Scientific operations commenced in June 2012 and more than 12,000 observations have since been performed at the ~0.12" visible-light diffraction limit. Two new infrared cameras providing high-speed tip-tilt sensing and a 2' field-of-view will be integrated in 2014. In addition to a Robo-AO clone for the 2-m IGO and the natural guide star variant KAPAO at the 1-m Table Mountain telescope, a second generation of facility-class Robo-AO systems are in development for the 2.2-m University of Hawai'i and 3-m IRTF telescopes which will provide higher Strehl ratios, sharper imaging, ~0.07", and correction to ? = 400 nm.

  17. Galactic astronomy with AO: nearby star clusters and moving groups

    NASA Astrophysics Data System (ADS)

    Davidge, T. J.

    2014-08-01

    Observations of Galactic star clusters and objects in nearby moving groups recorded with Adaptive Optics (AO) systems on Gemini South are discussed. These include observations of open and globular clusters with the GeMS system, and high Strehl L' observations of the moving group member Sirius obtained with NICI. The latter data fail to reveal a brown dwarf companion with a mass >= 0.02M? in an 18 × 18 arcsec2 area around Sirius A. Potential future directions for AO studies of nearby star clusters and groups with systems on large telescopes are also presented.

  18. High-Performance CCSDS AOS Protocol Implementation in FPGA

    NASA Technical Reports Server (NTRS)

    Clare, Loren P.; Torgerson, Jordan L.; Pang, Jackson

    2010-01-01

    The Consultative Committee for Space Data Systems (CCSDS) Advanced Orbiting Systems (AOS) space data link protocol provides a framing layer between channel coding such as LDPC (low-density parity-check) and higher-layer link multiplexing protocols such as CCSDS Encapsulation Service, which is described in the following article. Recent advancement in RF modem technology has allowed multi-megabit transmission over space links. With this increase in data rate, the CCSDS AOS protocol implementation needs to be optimized to both reduce energy consumption and operate at a high rate.

  19. Course Material Model in A&O Learning Environment.

    ERIC Educational Resources Information Center

    Levasma, Jarkko; Nykanen, Ossi

    One of the problematic issues in the content development for learning environments is the process of importing various types of course material into the environment. This paper describes a method for importing material into the A&O open learning environment by introducing a material model for metadata recognized by the environment. The first…

  20. Le contenu baryonique de l'univers révélé par les raies d'absorption dans le spectre des quasars

    NASA Astrophysics Data System (ADS)

    Petitjean, P.

    The baryons in the universe from quasar absorption line systems. Although steady progress is made towards detecting faint objects in emission, the high-redshift objects detected this way up to now are drawn from a particular population of powerful emitters. On the contrary, any standard object such as normal galaxies or intergalactic gaseous clouds close enough to the line of sight to high redshift quasars may be detectable by the absorption that it produces in the spectrum of the background quasar. The complete range of redshift is accessible from zero to the highest QSO redshift z=4.897. Absorption line systems observed in QSO spectra are generally classified into three categories. (1) The metal-line systems in which a large number of elements, in different ionization stages, is observed, from C{I} to C{IV} or O{I} to O{VI}. The Lyman limit systems (LLS) are optically thick at the H{I} Lyman limit (912 Å) and have therefore H{I} column densities N(H{I}) > 2× 10^{17} cm^{-2}. They are closely related, at any redshift, to galaxies. The latter have been detected by direct imaging and follow-up spectroscopy at low and intermediate redshift. Studying their number density and physical properties (kinematics, ionization state, abundances) is then a unique tool to trace galaxy formation. Among these systems, the rare damped systems, characterized by a very large H I column density (N(H{I}) > 2× 10^{20} cm^{-2}) are often considered to be associated with galactic or proto-galactic disks. (2) The hydrogen Ly α lines with no or very few metals detected at the same redshift, are of intergalactic origin at high redshift but could somehow be associated with galaxies at low redshift. Information about these systems (column density, Doppler parameter, kinematics, clustering) is derived from line-profile fitting. The latter requires high-resolution high-quality spectra that are difficult to obtain on 4m-class telescopes. Recent studies of absorptions coincident in redshift in the spectra of gravitationally lensed QSO images or QSO pairs have shown that the mean radius of the absorbers perpendicular to the line of sight is surprizingly large (up to 500 kpc). The idea that the Ly gas could trace the potential wells of dark matter and thus reveal its characteristical filamentary structure has been successfully investigated using N-body simulations. This has opened the prospect to study the cosmological evolution of the spatial distribution of the diffuse baryonic matter. (3) The broad absorption line (BAL) systems are characterized by impressive absorption troughs from different ions of low and high excitation, extending from 0 up to 60000 km s^{-1} outflow velocity relative to the QSO emission redshift. It is widely accepted that the gas is very close to the centre of the QSO host-galaxy and may be part of the broad emission line region. These systems are intimately related to the AGN phenomenon which is an important ingredient of galaxy formation. The amount of information derived from studies of QSO absorption line systems has increased tremendously in the last few years. This largely results from improvement of instrumental sensitivity, and spectral resolution and extension of the accessible wavelength range. Coupled with the development of sophisticated N-body simulations, this progress has favored the emergence of a consistent picture in which not only the intergalactic medium is the baryonic reservoir for galaxy formation but also galaxy formation strongly influences the evolution of the intergalactic medium through metal enrichment and ionizing radiation emission. One of the most exciting and promizing projects for the next few years may be to probe the 3D spatial distribution of the diffuse gas at high redshift. A number of large surveys are underway or planed, which will provide a large number of bright (m{V}<19) quasars for investigation of large scales. A few small fields will be searched for deeper samples of quasars (m{V}<23). If a hundred of lines of sight can be observed in one square degree, the probability distribution function of the matter density could be investigated at high redshift. This would be a unique way to study how galaxy formation is related to the distribution and dynamics of the underlying matter field. Même si des progrès considérables ont été faits ces dernières années dans l'observation d'objets à grand décalage spectral, ceux qui sont détectés par leur émission sont issus d'une population d'émetteurs puissants. Au contraire, n'importe quel objet aussi anodin qu'une galaxie normale ou un nuage intergalactique, se trouvant interposé entre nous et un quasar de grand décalage spectral, engendre une absorption dans le spectre du quasar. Ainsi, les raies d'absorption dans le spectre des quasars permettent de sonder l'univers sur toute la ligne de visée de notre époque (z=0) jusqu'au décalage spectral du plus éloigné des quasars (actuellement z=4,897). Les systèmes d'absorption sont généralement classés en trois catégories. (1) Les systèmes contenant des éléments lourds (différents de l'hydrogène et l'hélium) pour lesquels des raies de nombreux ions peuvent être détectées, de C{I} à C{IV} ou de O{I} à O{VI}. Parmi ceux-ci, les systèmes optiquement épais à la limite de Lyman sont souvent associés à des galaxies que l'on détecte facilement jusqu'à des décalages spectraux de l'ordre de z thicksim 1. Les systèmes plus rares possédant une très forte densité de colonne (N(H{I}) > 2× 10^{20} cm^{-2}), que l'on appelle les systèmes lorentziens sont, à grand décalage spectral, probablement associés à des disques proto-galactiques. (2) Les systèmes de la forêt Lyman α sont très nombreux et ne contiennent que très peu d'éléments lourds. Ils sont associés à du gaz remplissant le milieu intergalactique. Les caractéristiques physiques des raies (paramètre Doppler, densité de colonne, regroupement) sont dérivées à partir de la modélisation de leur profil. Cela ne peut se faire que sur des données de très bonne qualité qu'il est difficile d'obtenir sur les télescopes de la classe des 4m. En utilisant des lignes de visée proches (images gravitationnelles multiples de quasars ; groupes de quasars rapprochés dans le ciel), on peut évaluer la dimension transversale des nuages qui se révèle être étonnamment grande, de l'ordre de 500 kpc. L'idée que le gaz puisse tracer le potentiel de la matière noire et se répartir le long des structures filamentaires dessinées par celle-ci a été approfondie avec succès grâce à des simulations N-corps récentes. La perspective est ouverte de pouvoir étudier l'évolution cosmologique des grandes structures de l'univers en cartographiant la matière baryonique diffuse. (3) Les systèmes à raies larges (BAL) sont caractérisés par des absorptions s'étendant sur plusieurs dizaines de milliers de kilomètres par seconde. Il s'agit certainement de gaz éjecté par le quasar, qui pourrait faire partie de la région qui émet les raies en émission larges, caractéristiques du spectre des quasars. Ces systèmes sont des sources d'information unique sur les noyaux actifs de galaxie. La quantité d'information déduite des études des systèmes de raies d'absorption dans le spectre des quasars a augmenté de façon considérable ces dernières années. Ceci est dû à l'amélioration de la sensibilité instrumentale et donc de la résolution spectrale des observations, mais aussi à l'élargissement du domaine spectral qu'il est possible d'observer. Ces progrès ont été accompagnés par le développement de simulations numériques détaillées qui ont permis l'émergence d'un modèle cohérent dans lequel le milieu intergalactique est le réservoir de gaz pour la formation des galaxies. Cette dernière en retour influence l'évolution du milieu intergalactique à travers l'éjection des éléments lourds et l'émission de rayonnements ionisants. Un des projets les plus prometteurs de ces prochaines années est de cartographier la distribution spatiale du gaz à grand décalage spectral. Les grands relevés de quasars, maintenant planifiés, vont permettre d'augmenter de façon considérable le nombre de quasars brillants connus qui seront utilisés pour révéler, grâce aux absorptions produites par le gaz, les grandes structures de l'univers. Quelques champs vont être étudiés plus en détail, dans lesquels les quasars seront recherchés jusqu'aux plus faibles luminosités. Si une centaine de lignes de visée peuvent être observées dans un degré carré, le champ de densité de la matière pourrait être reconstruit. C'est un moyen unique d'étudier comment la formation des galaxies est liée à la distribution et la dynamique du gaz dans le milieu intergalactique.

  1. Holocene Evolution of Qing'ao Embayment, Southern China

    NASA Astrophysics Data System (ADS)

    Switzer, A. D.; Yu, F.; Chen, B.; Zheng, Z.; Wang, D.

    2012-12-01

    The Holocene evolution of the Qing'ao embayment, Nan'ao Island, southern China, is primarily the result of the interaction of tectonic activity, climate variation and changes in relative sea level. Characterizing the evolutionary history of the relatively small Qing'ao embayment during the Holocene will help improve our understanding of the driving mechanisms of coastal evolution in the area. To reconstruct the Holocene evolution history we analyzed the grain size, loss on ignition (LOI) and carbonate content of modern and core samples. Modern environmental analogs were examined in surface samples ranging from the coastal sand dunes through to offshore. The results of these modern samples suggest that dune sand (mean size of ~2.33Phi) are slightly finer than beach sand (mean size of 2.13Phi), and nearshore sediment is much coarser than offshore sediment (mean size of 5.90Phi). This modern analogs were then applied to 8 percussion cores from the Qing'ao embayment. A chronological framework obtained from 11 radiocarbon samples suggests that the embayment started to accept deposition since early Holocene, ~8500 cal. yr. BP. Three main phases of Holocene evolution were identified. A basin wide shell-rich sand sheet forms the basal Holocene facies and overlies clay rich presumably Pleistocene sediments or bedrock. This facies records an initial sedimentation phase associated with the early Holocene transgression into the embayment (~8500-6000 cal. yr. BP). The basal facies grades upward to a mixed sandy-mud facies which includes lagoonal clayey-silts, flood tide delta sands and records an estuarine phase lasting from ~6000-1000 cal. yr. BP that appears coincident with falling regional sea levels. Coincident with the estuarine phase is a period of coastal dune building recorded as yet undated massive sands that are found in the upper fill. Toward the end of the estuarine phase it is apparent that dune migration has restricted the lagoon entrance and that this was contemporaneous with the final stages of infilling of the lagoon. The final phase of sedimentation is recorded as a thin terrestrial sequence dominated by fluvial floodplain facies that covers the last ~1000 cal. yr. BP and is topped by soils that also record enhanced anthropogenic modification over the last 1000 years. Our early results suggest that sea level and accomodation space are the main drivers for evolution of the Qing'ao embayment, as climate change during the Holocene in this region is relatively insignificant. However, as this area is reported to be tectonically active the impact of the tectonic movements on the evolution of Qing'ao embayment still requires further investigation.

  2. Real-time control system verification for ELT AO systems

    NASA Astrophysics Data System (ADS)

    Basden, Alastair; Myers, Richard; Morris, Tim; Bharmal, Nazim; Bitenc, Urban; Dipper, Nigel; Reeves, Andrew; Gendron, Eric; Rousset, Gérard; Hubert, Zoltan; Vidal, Fabrice; Matin, Olivier; Gratadour, Damien; Chemla, Fanny

    2013-12-01

    ELT AO systems have demanding computational requirements for real-timecontrol. These systems are required to be fully tested and robustbefore commissioning so that valuable on-sky time is not wasted. Inthis talk I will report recent work at Durham on our ELT AO real-timecontrol system, algorithms that we use to improve robustness, anddevelopment of an end-to-end testing environment that will allow fulltesting of real-time control systems, including both Monte-Carlosimulation and hardware approaches. The talk will include experiencegained with CANARY, how the robustness of this system has beenimproved, and our experience operating with four laser guide stars. Workcarried out in this area on the DRAGON test-bench will also bedescribed.

  3. Intelligent vibration control of ELTs and large AO hardware

    NASA Astrophysics Data System (ADS)

    Pott, J.-U.; Kürster, M.; Trowitzsch, J.; Borelli, J.; Rohloff, R.-R.; Herbst, T.; Böhm, M.; Keck, A.; Ruppel, T.; Sawodny, O.

    2012-07-01

    MPIA leads the construction of the LINC-NIRVANA instrument, the MCAO-supported Fizeau imager for the LBT, serves as pathfinder for future ELT-AO imagers in terms of size and technology. In this contribution, we review recent results and significant progress made on the development of key items of our stratgey to achieve a piston stability of up to 100nm during a science exposure. We present an overview of our vibration control strategies for optical path and tip-tilt stabilization, involving accelerometer based real-time vibration measurements, vibration sensitive active control of actuators, and the development of a dynamical model of the LBT. MPIA also co-develops the E-ELT first-light NIR imager MICADO (both SCAO and MCAO assisted). Our experiences, made with LINC-NIRVANA, will be fed into the MICADO structural AO design to reach highest on-sky sensitivity.

  4. On random walk de Lévy aplicado aos mapas de variâncias

    NASA Astrophysics Data System (ADS)

    Klafke, J. C.

    2003-08-01

    Uma pergunta que surge ao nos confrontarmos com os mapas de variâncias, ou s-Maps [Klafke, J. C. "Estudo da Difusão Caótica em Ressonâncias Asteroidais", Tese de Doutorado, IAG/USP, 2002] diz respeito ao conteúdo físico de tais representações do espaço de fase. Ou seja, o que representa as variâncias das ações obtidas para uma determinada condição inicial e como relacioná-las com o tempo de difusão das órbitas, supondo-se que estas de fato estejam envolvidas em um processo difusivo? Para discutirmos essa questão, lançamos mão da modelagem dos processos estocásticos subjacentes às variâncias determinadas e implementamos uma série de simulações do tipo Monte Carlo a partir das informações registradas nos s-Maps calculados para algumas ressonâncias asteroidais bem estudadas (p.ex. 3: 1, 2: 1 e 3: 2). Para tanto, temos usado uma função de densidade de probabilidade gaussiana ao definir os n passos que permitirão estabelecer uma relação direta entre o Mapa de Difusão e o Mapa de Variâncias. Contudo, os resultados obtidos até agora tem subestimado o tempo de difusão esperado para os fenômenos conhecidos. Tal se deve ao fato de que, no processo difusivo real, é possível existirem passos de comprimento consideravelmente maiores que a média estabelecida pelas distribuições gaussiana ou normal, sobretudo quando se cruza uma região caótica. Neste trabalho, apresentamos os resultados comparativos de simulações de Monte Carlo com base no random walk de Lévy [Klafter, J. et al. 2002. "Beyond Brownian motion", Phys. Today, Feb, 33-39.], o qual possibilita passos esporádicos de comprimento acima do valor médio (saltos) permitindo estabelecer uma escala de tempo mais próxima da esperada para a difusão.

  5. High-Resolution Imaging of Asteroids/Satellites with AO

    NASA Astrophysics Data System (ADS)

    Merline, William

    2012-02-01

    We propose to make high-resolution observations of asteroids using AO, to measure size, shape, and pole position (spin vectors), and/or to search for satellites. We have demonstrated that AO imaging allows determination of the pole/dimensions in 1 or 2 nights on a single target, rather than the years of observations with lightcurve inversion techniques that only yield poles and axial ratios, not true dimensions. Our new technique (KOALA) combines AO imaging with lightcurve and occultation data for optimum size/shape determinations. We request that LGS be available for faint targets, but using NGS AO, we will measure several large and intermediate asteroids that are favorably placed in spring/summer of 2012 for size/shape/pole. Accurately determining the volume from the often-irregular shape allows us to derive densities to much greater precision in cases where the mass is known, e.g., from the presence of a satellite. We will search several d! ozen asteroids for the presence of satellites, particularly in under-studied populations, particularly NEOs (we have recently achieved the first-ever optical image of an NEO binary [Merline et al. 2008b, IAUC 8977]). Satellites provide a real-life lab for testing collisional models. We will search for satellites around special objects at the request of lightcurve observers, and we will make a search for debris in the vicinity of Pluto, in support of the New Horizons mission. Our shape/size work requires observations over most of a full rotation period (typically several hours).

  6. Single-shot retinal imaging with AO spectral OCT

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Rha, Jungtae; Jonnal, Ravi S.; Miller, Donald T.

    2005-04-01

    We demonstrate for the first time an adaptive optics (AO) spectral OCT retina camera that acquires with unprecedented 3D resolution (2.9 ?m lateral; 5.5 ?m axial) single shot B-scans of the living human retina. The camera centers on a Michelson interferometer that consists of a superluminescent diode for line illuminating the subject's retinal; voice coil translator for controlling the optical path length of the reference channel; and an imaging spectrometer that is cascaded with a 12-bit area CCD array. The imaging spectrometer was designed with negligible off-axis aberrations and was constructed from stock optical components. AO was integrated into the detector channel of the interferometer and dynamically compensated for most of the ocular aberration across a 6 mm pupil. Short bursts of B-scans, with 100 Ascans each, were successfully acquired at 1 msec intervals. Camera sensitivity was found sufficient to detect reflections from all major retinal layers. Individual outer segments of photoreceptors at different retinal eccentricities were observed in vivo. Periodicity of the outer segments matched cone spacing as measured from AO flood illuminated images of the same patches of retina.

  7. LDEF results for polymer matrix composite experiment AO 180

    NASA Technical Reports Server (NTRS)

    Tennyson, R. C.

    1992-01-01

    This report represents a summary of the results obtained to-date on a polymer matrix composite experiment (AO 180) located at station D-12, about 82 deg off the 'ram' direction. Different material systems comprised of graphite, boron, and aramid (Kevlar) fiber reinforcements were studied. Although previous results were presented on in-situ thermal-vacuum cycling effects, particularly dimensional changes associated with outgassing, additional comparative data will be shown from ground-based tests on control and flight samples. The system employed was fully automated for thermal-vacuum cycling using a laser interferometer for monitoring displacements. Erosion of all three classes of materials due to atomic oxygen (AO) will also be discussed, including angle of incidence effects. Data from this experiment will be compared to published results for similar materials in other LDEF experiments. Composite materials' erosion yields will be presented on an AO design nomogram useful for estimating total material loss for given exposure conditions in low Earth orbit (LEO). Optical properties of these materials will also be compared with control samples. A survey of the damage caused by micrometeoroids/debris impacts will be addressed as they relate to polymer matrix composites. Correlations between hole size and damage pattern will be given. Reference to a new nomogram for estimating the number distribution of micrometeoroid/debris impacts for a given space structure as a function of time in LEO will be addressed based on LDEF data.

  8. SIMS chemical and isotopic analysis of impact features from LDEF experiments AO187-1 and AO187-2

    NASA Technical Reports Server (NTRS)

    Stadermann, Frank J.; Amari, Sachiko; Foote, John; Swan, Pat; Walker, Robert M.; Zinner, Ernst

    1995-01-01

    Previous secondary ion mass spectrometry (SIMS) studies of extended impact features from LDEF capture cell experiment AO187-2 showed that it is possible to distinguish natural and man-made particle impacts based on the chemical composition of projectile residues. The same measurement technique has now been applied to specially prepared gold target impacts from experiment AO187-1 in order to identify the origins of projectiles that left deposits too thin to be analyzed by conventional energy-dispersive x-ray (EDX) spectroscopy. The results indicate that SIMS may be the method of choice for the analysis of impact deposits on a variety of sample surfaces. SIMS was also used to determine the isotopic compositions of impact residues from several natural projectiles. Within the precision of the measurements all analyzed residues show isotopically normal compositions.

  9. Intramedullary locking femoral nails. Experience with the AO nail.

    PubMed Central

    Fogarty, A. B.; Yeates, H. A.

    1991-01-01

    The AO interlocking nail was introduced to the Ulster Hospital, Dundonald in 1988 and since then has been used in over 50 patients with femoral shaft fractures. We have reviewed 45 patients with 46 femoral shaft fractures treated between June 1988 and April 1990. These included four compound fractures and 13 comminuted fractures. The results compare favourably with other series. The union rate was 98% and there were no instances of deep infection. The alternative treatment methods available are discussed along with a review of the relevant literature. Images Fig 3 Fig 5 PMID:1785145

  10. Aspect-Oriented Business Process Modeling with AO4BPMN

    NASA Astrophysics Data System (ADS)

    Charfi, Anis; Müller, Heiko; Mezini, Mira

    Many crosscutting concerns in business processes need to be addressed already at the business process modeling level such as compliance, auditing, billing, and separation of duties. However, existing business process modeling languages including OMG's Business Process Modeling Notation (BPMN) lack appropriate means for expressing such concerns in a modular way. In this paper, we motivate the need for aspect-oriented concepts in business process modeling languages and propose an aspect-oriented extension to BPMN called AO4BPMN. We also present a graphical editor supporting that extension.

  11. Akreos Adapt AO Intraocular Lens Opacification: A Case Report

    PubMed Central

    Forlini, Matteo; Orabona, Giancarlo Dell'Aversana; Bratu, Adriana Ionela; Rossini, Paolo; Cavallini, Gian Maria; Forlini, Cesare

    2013-01-01

    A 79-year-old hyperglycemic patient was referred to the ‘Santa Maria delle Croci’ Hospital, Ravenna, Italy. He presented with visual impairment in the right eye. Four years ago, he had had an uneventful cataract surgery in the right eye. We observed an opacification of the intraocular lens (IOL) causing significant visual disturbance. The IOL was exchanged. Unfortunately, pathologic analysis was not performed. Patient-related factors such as hyperglycemia and hypertension might have been responsible for the opacification. To our knowledge, there is only one previous report of opacification of the Akreos Adapt AO IOL. PMID:24163684

  12. d-AO spherical aromaticity in Ce6 O8.

    PubMed

    Yu, Xiaohu; Oganov, Artem R; Popov, Ivan A; Boldyrev, Alexander I

    2016-01-01

    After the first introduction of ? aromaticity in chemistry to explain the bonding, structure, and reactivity of benzene and its derivatives, this concept was further applied to many other compounds featuring other types of aromaticity (i.e., ?, ?). Thus far, there have been no reports on d-AO-based spherical ? aromaticity. Here, we predict a highly stable bare Ce6 O8 cluster of a spherical shape using evolutionary algorithm USPEX and DFT?+?U calculations. Natural bond orbital analysis, adaptive natural density partitioning algorithm, electron localization function, and partial charge plots demonstrate that bare Ce6 O8 cluster exhibits d-AO spherical ? aromaticity, thus explaining its exotic geometry and stability. Ce6 O8 complex plays an important role in many reactions and is known to exist in many forms, such as in NH4 [Ce6 (?(3) O)5 (?(3) OH)3 (?(2) -C6 H5 COO)9 (NO3 )3 (DMF)3 ]*DMF*H2 O compound, which is prepared under room temperature, and acts as an oxidizing agent. © 2015 Wiley Periodicals, Inc. PMID:26284694

  13. Nao/ao Variability In The Coupled Bergen Climate Model

    NASA Astrophysics Data System (ADS)

    Sorteberg, A.; Furevik, T.; Bentsen, M.; Drange, H.; Kvamsto, N. G.; Thorstensen-Kindem, I.

    A new fully coupled atmosphere-ocean-sea ice model, known as the Bergen Climate Model (BCM), has been developed. The coupled model can be run with stretched co- ordinates both in the atmosphere and ocean and consists of the atmospheric model ARPEGE/IFS, and a global version of the isopycnal ocean model MICOM, including a sea ice model. The atmospheric model ARPEGE/IFS (c22) is a spectral model devel- oped jointly by Meteo-France and the European Centre for Medium-Range Weather Forecasts (ECMWF). The ocean circulation model is the Miami Isopycnic Coordinate Ocean Model (MI- COM). Several modifications have been done to the MICOM model including the incorporation of a thermodynamic and dynamic sea ice model, the use of tempera- ture as a prognostic variable instead of salinity, and the use of a metric scale factor in both lateral, so the model can easily be configured on a general orthogonal grid. Also,the thickness diffusion has been modified to better handle diffusion near bottom topography and the base of the mixed layer. Coupling has been done with the library OASIS where 14 different fields are ex- changed using Montecarlo mapping and subgrid interpolation. Continental runoff into the correct rivers and discharge into the correct ocean grid cells are performed using the Total Runoff Integrating Pathways (TRIP) data set. Results will be present from a 300 years flux adjusted control integration of BCM with todays climate, using a unstretched T63 truncation in the atmosphere and a 0.8 by 2.4 degree resolution (near the equator gradually transforming to approximate square grid cells towards the poles) in the ocean. The model output has been analysed for large scale variability in both the ocean and atmosphere, with emphasise on the North Atlantic and Arctic climate. Statistical properties of the NAO/AO signal, and its im- pacts on the climate components, are identified and compared with observations. The NAO/AO mode of variability show up in the model with realistic amplitudes and fre- quencies in both 2m temperature and SLP and emphasis will be placed on evaluation of the models ability to reproduce known relations between different meteorological variables and the NAO/AO signal.

  14. LDEF (Prelaunch), AO201 : Interplanetary Dust Experiment, Tray G10

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The prelaunch photograph shows the Inter planetary Dust Experiment (IDE) in a three (3) inch deep corner tray. The IDE is an active exper iment and is located on the earth facing end of the LDEF in the G10 location. AO201 - The Interplanetary Dust Experiment (IDE) is an active experiment consisting of impact detectors, detector frames, a solar sensor and the necessary mounting hardware. The eighty (80) detectors, metal-oxide-silicon (MOS) capacitor-type impact sensors, bonded into anodized alumi num frames, are attached to the aluminum mounting plate with non-magnetic stainless steel fas teners. A solar sensor, four (4) silicon solar cells in series mounted on an aluminum baseplate, is shown in the approximate center of the IDE mounting plate. The different colors seen on the detectors are the reflections of LDEF technicians and the surrounding clean room work area.

  15. NFIRAOS: first facility AO system for the Thirty Meter Telescope

    NASA Astrophysics Data System (ADS)

    Herriot, Glen; Andersen, David; Atwood, Jenny; Boyer, Corinne; Byrnes, Peter; Caputa, Kris; Ellerbroek, Brent; Gilles, Luc; Hill, Alexis; Ljusic, Zoran; Pazder, John; Rosensteiner, Matthias; Smith, Malcolm; Spano, Paolo; Szeto, Kei; Véran, Jean-Pierre; Wevers, Ivan; Wang, Lianqi; Wooff, Robert

    2014-07-01

    NFIRAOS, the Thirty Meter Telescope's first adaptive optics system is an order 60x60 Multi-Conjugate AO system with two deformable mirrors. Although most observing will use 6 laser guide stars, it also has an NGS-only mode. Uniquely, NFIRAOS is cooled to -30 °C to reduce thermal background. NFIRAOS delivers a 2-arcminute beam to three client instruments, and relies on up to three IR WFSs in each instrument. We present recent work including: robust automated acquisition on these IR WFSs; trade-off studies for a common-size of deformable mirror; real-time computing architectures; simplified designs for high-order NGS-mode wavefront sensing; modest upgrade concepts for high-contrast imaging.

  16. The 1987 outburst of the BL Lacertid AO 0235 + 164

    NASA Astrophysics Data System (ADS)

    Webb, J. R.; Smith, A. G.

    1989-08-01

    The violently variable BL Lacertid AO 0235 + 164 displayed a 3.24 magnitude outburst in early 1987. This outburst was observed intensively from Rosemary Hill Observatory in three colors. Long term monitoring observations made at Rosemary Hill are examined in an effort to find any recurring timescales associated with this outburst and previous large amplitude outbursts. The energetics of the 1987 outburst are analyzed in terms of the Shields and Wheeler model of a magnetized accretion disk. The timescales identified in the power spectrum (2.8 and 1.6 yr) are input into the model as the storage timescales. Since the emitted energy calculated from the optical burst cannot be stored in a magnetized disk at an allowable radius, it is concluded that either the storage timescales are longer than those identified in the power spectrum, or relativistic beaming effects must be considered, with a Doppler factor of 1.3 to 1.6.

  17. LDEF (Postflight), AO201 : Interplanetary Dust Experiment, Tray H11

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO201 : Interplanetary Dust Experiment, Tray H11 The Interplanetary Dust Experiment hardware has a thin brown stain on the exposed surfaces. A deeper brown stain, probably from the material underneath the small electrical cover plate of the detector frame, can be seen in the upper right corner of some of the detectors. Stain that was seen on the solar sensor base plate in the flight photograph cannot be seen because of reflected light. The colors seen in the detector's mirror like surface are reflections of the surrounding area. A dark spot seen on a detector in the third row from the top in the flight photograph, was not found in a postflight inspection. A close inspection of this photograph does reveal several impact damage locations.

  18. HST and Keck AO Images of Vortices on Jupiter

    NASA Astrophysics Data System (ADS)

    de Pater, Imke; Wong, M.; Luszcz-Cook, S.; Adamkovics, M.; Marcus, P.; Asay-Davis, X.; Conrad, A.; Go, C.

    2009-09-01

    Observations of Jupiter were conducted in April 2006 and May 2008 with both HST (250-890 nm) and the 10-m Keck telescope. On Keck we used the near-infrared camera NIRC2, coupled to the AO system, at 1.2 to 5 micrometers. At 5 um we are sensitive to Jupiter's thermal emission in cloud-free regions of the atmosphere, while at 1.2 um we see reflected sunlight from hazes and clouds in the troposphere-stratosphere. All small ovals (i.e., all except for Oval BA and the GRS) appear to be surrounded by bright rings at 5 mu, with typical brightness temperatures of 225-250 K, and hence probing depths to 2.5-4 bar. We argue that the small vortices are columnar structures, extending down into the water cloud. Air is rising along the center of these vortices, and descending around the outer periphery; the storm systems are likely fueled by the latent heat released from the water cloud. The descending part of the vertical circulation in the larger ovals is within the ovals, likely at the location of the red ring in Oval BA, which may indicate the maximum radial distance where such return flows can take place. On 19 July 2009, amateur observer Anthony Wesley (Australia) reported a dark spot/streak on Jupiter, near a southern latitude of 56 deg, which he attributed to an impact (analogous to the SL9 impact on Jupiter). We are scheduled to observe Jupiter with the Keck AO system on 24 July 2009 UT; if observations are successful, we will report preliminary results.

  19. Robo-AO: autonomous and replicable laser-adaptive-optics and science system

    NASA Astrophysics Data System (ADS)

    Baranec, C.; Riddle, R.; Ramaprakash, A. N.; Law, N.; Tendulkar, S.; Kulkarni, S.; Dekany, R.; Bui, K.; Davis, J.; Burse, M.; Das, H.; Hildebrandt, S.; Punnadi, S.; Smith, R.

    2012-07-01

    We have created a new autonomous laser-guide-star adaptive-optics (AO) instrument on the 60-inch (1.5-m) telescope at Palomar Observatory called Robo-AO. The instrument enables diffraction-limited resolution observing in the visible and near-infrared with the ability to observe well over one-hundred targets per night due to its fully robotic operation. Robo-AO is being used for AO surveys of targets numbering in the thousands, rapid AO imaging of transient events and long-term AO monitoring not feasible on large diameter telescope systems. We have taken advantage of cost-effective advances in deformable mirror and laser technology while engineering Robo-AO with the intention of cloning the system for other few-meter class telescopes around the world.

  20. LDEF (Flight), AO038 : Interstellar Gas Experiment, Tray E12

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO038 : Interstellar Gas Experiment, Tray E12 The flight photograph was taken from the Orbiter aft flight deck during the LDEF retrieval. During the mission, the tray surface was at an angle of approximately ninety-eight (98) degrees to the orbital velocity vector and therefore exposed to a lower atomic oxygen flux than if parallel with the velocity vector. A very light stain is present on the white paint dots on experiment tray clamps along the lower edge of the tray. The color of the white thermal control paint on the IGE has changed and now varies from white to differing shades of brown. The darker brown areas on the experiment baseplate, around the grid voltage cable connectors, appear to have come from contaminants flowing from inside the LDEF. The shadows from the tray sidewalls hide most of the dark stain in the upper right corner of the tray. A lighter stain coats the tray's upper side wall, the left side of the canister housing and the experiment baseplate. The insulation on the grid voltage cable that was transparent prior to launch is now a light tan color.

  1. LDEF (Flight), AO038 : Interstellar Gas Experiment, Tray H06

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO038 : Interstellar Gas Experiment, Tray H06 The flight photograph was taken from the Orbiter aft flight deck during the LDEF retrieval. A very light contamination stain is present on the experiment tray flanges and on the most of the visible LDEF structure. The exception being a much darker stain on the structure adjacent to thermal covers that provide venting for the LDEF interior. The paint dot, originally white, adjacent to the thermal cover vent area is heavily coated with the brown contamination stain while the paint dot adjacent to the center end cover plate has a very light coating. The color of the white thermal control paint on the IGE has changed and now varies from offwhite to a dark brown. The darker brown areas on the experiment baseplate, around the grid voltage cable connectors, appear to have come from contaminants flowing from inside the LDEF. A dark stain area can be seen on the tray's lower sidewall but a shadow hides most of the dark stain in the upper left corner of the tray. A lighter stain coats portions of the experiment baseplate and the outside of the canister housing. A beryllium copper collector foil is clearly visible in the lower left canister housing as are the baffles and reflected light from the fine wire mesh grid near the top of the canister housing. Due to an experiment system malfunction, the canister collector foils that are visible were exposed for the total mission.

  2. LDEF (Flight), AO038 : Interstellar Gas Experiment, Tray H09

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO038 : Interstellar Gas Experiment, Tray H09 The flight photograph of the Interstellar Gas Experiment was taken from the Orbiter aft flight deck during the LDEF retrieval. A very light contamination stain is present on the experiment tray flanges and on the most of the visible LDEF structure. The exception being a darker stain on the structure adjacent to thermal covers that provide venting for the LDEF interior. Both paint dots appear to be heavily coated with the brown contamination stain. The color of the white thermal control paint on the IGE has changed and now varies from off-white to a dark brown. The darker brown areas on the experiment baseplate, around the grid voltage cable connectors, appear to have come from contaminants flowing from inside the LDEF. A dark stain area can be seen on the lower half of the tray's right sidewall but a shadow hides most of the dark stain in the upper left corner of the tray. A lighter stain coats portions of the experiment baseplate and the outside of the canister housing. A beryllium copper collector foil is clearly visible in the lower left canister housing as are the baffles and reflected light from the fine wire mesh grid near the top of the canister housing. Due to an experi- ment system malfunction, the canister collector foils that are visible were exposed for the total mission.

  3. Atomic oxygen effects on LDEF experiment AO171

    NASA Technical Reports Server (NTRS)

    Whitaker, Ann F.; Kamenetzky, Rachel R.; Finckenor, Miria M.; Norwood, Joseph K.

    1993-01-01

    The Solar Array Materials Passive Long Duration Exposure Facility (LDEF) Experiment (SAMPLE), AO171, contained in total approximately 100 materials and materials processes with a 300 specimen complement. With the exception of experiment solar cell and solar cell modules, all test specimens were weighed before flight, thus allowing an accurate determination of mass loss as a result of space exposure. Since almost all of the test specimens were thermal vacuum baked before flight, the mass loss sustained can be attributed principally to atomic oxygen attack. The atomic oxygen effects observed and measured in five classes of materials is documented. The atomic oxygen reactivity values generated for these materials are compared to those values derived for the same materials from exposures on short term shuttle flights. An assessment of the utility of predicting long term atomic oxygen effects from short term exposures is given. This experiment was located on Row 8 position A which allowed all experiment materials to be exposed to an atomic oxygen fluence of 6.93 x 10(exp 21) atoms/cm(sup 2) as a result of being positioned 38 degrees off the RAM direction.

  4. LDEF (Postflight), AO201 : Interplanetary Dust Experiment, Tray G10

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO201 : Interplanetary Dust Experiment, Tray G10 The IDE experiment appears to be in excellent condition in the postflight photograph. All bond joints seem to have survived the space environment and the experiment hardware seems to be intact. The direction and intensity of the artificial light source has caused hot spots and reflections that tend to wash out the brown stain on the exposed surfaces. A close inspection of individual detectors reveal locations where impacts have occurred and damage is present. In the detector layout in the lower left corner of the tray, two detectors continue to show the discolorations observed in the flight photograph. A triangular shape can be seen in the detector located in the second horizontal row from the bottom and the second vertical row from the left. The other detector, located in the third horizontal row from the bottom and the fourth vertical row from the left has an irregular shaped, very faint, discolora tion. The blue color in the detectors metallic surface is caused by reflections of the surrounding area.

  5. Ruled and holographic experiment (AO 138-5)

    NASA Astrophysics Data System (ADS)

    Bonnemason, Francis

    1993-04-01

    The AO 138-5 experiment was designed, via the FRECOPA (FRench COoperative PAyload) experiment with the aim to study the optical behavior of different diffraction gratings submitted to space vacuum long exposure and solar irradiation. Samples were ruled and holographic gratings, masters or replica, and some additional control mirrors with various coatings. The experiment was located on the B3, trailing edge of the LDEF and was protected against Atomic Oxygen flux. The experienced thermal cycling was evaluated from -23 C to 66 C during the flight, 34,000 orbits. The samples (two batches of four pieces) were located on a dedicated plate, by a pair of equivalent gratings or mirrors; optical faces were located on the external side. The plate was inside a canister, which had been opened in space for ten months. When the satellite returned to Kennedy Space Center, the remaining vacuum in the canister was still correct. The analysis focused on the triple point characterization including light efficiency, wavefront flatness quality and stray light level. Tests were conducted on control mirrors and gratings (rules and holographic master or replica) loaded but not exposed to cosmic dust or direct solar irradiations. They did not show any significant variations. Solar exposure had damaged the coating (aluminum and platinum) reflectivity in the Ultra-Violet region; the degradation is higher with the gratings, in terms of efficiency. However, wavefront flatness quality and stray light level tests revealed no additional changes.

  6. LDEF (Prelaunch), AO038 : Interstellar Gas Experiment, Tray F06

    NASA Technical Reports Server (NTRS)

    1984-01-01

    LDEF (Prelaunch), AO038 : Interstellar Gas Experiment, Tray F06 The prelaunch photograph provides a view of the Interstellar Gas Experiment (IGE) hardware and shows a single experiment canister housing mounted in a twelve (12) inch deep peripheral tray. The experiment utilizes seven (7) canisters containing high-purity beryllium copper collecting foils, three (3) located in peripheral trays and four (4) located in trays on the space end of the LDEF, to meet experiment objectives. The active portion of the experiment consist of canister electronic timing devices and pyrotechnic cutters that control the exposure time of each collector foil. An electronic voltage multiplier system provides a bias voltage to the grid network located above the beryllium copper collecting foils.The batteries and the electronics are housed beneath the experiment baseplate facing the LDEF interior. The white painted surface area within the LDEF tray provides the optical properties required to maintain the experiment components within temperature limits. The rectangular opening in the upper right corner of the experiment baseplate provide the mounting for the ground support equipment test connector. The white grid voltage connector box, mounted on the side of the canister housing, provides the termination point for the cables running from the grid voltage box beneath the baseplate. The canister housing is a welded aluminum structure with aluminum mounting flanges. The experiment components are assembled using non-magnetic stainless steel fasteners. The aluminum housing cover, removed prior to flight, protects experiment components from damage and large particle contamination during ground handling.

  7. LDEF (Postflight), AO038 : Interstellar Gas Experiment, Tray H09

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO038 : Interstellar Gas Experiment, Tray H09 The post landing Interstellar Gas Experiment photograph was taken from the Orbiter's cargo bay access hatch during post landing operations to prepare the Orbiter for the ferry flight from the Dryden Flight Research Center to the Kennedy Space Center. A very light contamination stain is present on the experiment tray flanges and on the most of the visible LDEF structure. The exception being the darker stain on the structure adjacent to thermal covers that provide venting for the LDEF interior. Both paint dots appear to be heavily coated with the brown contamination stain. The color of the white thermal control paint on the IGE has changed and now varies from off-white to a dark brown. The darker brown areas on the experiment baseplate, around the grid voltage cable connectors, appear to have come from contaminants flowing from inside the LDEF. A dark stain area can be seen on the lower half of the tray's left sidewall and in the lower left corner of the tray. A lighter stain coats portions of the experiment baseplate and the outside of the canister housing. A beryllium copper collector foil is clearly visible in the upper left canister housing as are the baffles and reflected light from the fine wire mesh grid near the top of the canister housing. Due to an experiment system malfunction, the canister collector foils that are visible were exposed for the total mission.

  8. The AO Ulnar Shortening Osteotomy System Indications and Surgical Technique

    PubMed Central

    Nagy, Ladislav; Jungwirth-Weinberger, Anna; Campbell, Douglas; Pino, Juan González del

    2014-01-01

    Ulnar shortening osteotomy is an established and frequently performed surgical procedure in wrist surgery. The technical aspects of the procedure have continued to develop in recent years, with instruments and implants being developed specifically for this purpose. Ulnar shortening osteotomy is required for different clinical indications and situations. These varying indications demand different amounts of shortening, but all must be precise and accurate. Controversy exists as to how this can best be achieved in terms of the location for osteotomy, the surgical approach and geometry of the osteotomy, as well as which implant to use to provide optimal stability. The goal of all techniques (besides successfully resolving the underlying problem) is to achieve reliable and rapid bone union without compromising early functional rehabilitation and also to avoid hardware complications. The AO Hand Expert Group has developed a specialized instrumentation system with dedicated and specifically designed implants to ensure exact and accurate cutting with precise and rigid stabilization of the ulna. The matched drill guides and double-blade saws allow accurate completion of the planned amount of shortening together with precise coaptation of the osteotomy fragments. The specific ulnar osteotomy LCP (locking compression plate) combines maximum stability with minimum bulk and soft tissue irritation. The features of the implant, its surgical technique, and early results are described. PMID:25077046

  9. Robo-AO KP: A new era in robotic adaptive optics

    NASA Astrophysics Data System (ADS)

    Riddle, Reed L.; Baranec, Christoph; Law, Nicholas M.; Kulkarni, Shrinivas R.; Duev, Dmitry; Ziegler, Carl; Jensen-Clem, Rebecca M.; Atkinson, Dani Eleanor; Tanner, Angelle M.; Zhang, Celia; Ray, Amy

    2016-01-01

    Robo-AO is the first and only fully automated adaptive optics laser guide star AO instrument. It was developed as an instrument for 1-3m robotic telescopes, in order to take advantage of their availability to pursue large survey programs and target of opportunity observations that aren't possible with other AO systems. Robo-AO is currently the most efficient AO system in existence, and it can achieve an observation rate of 20+ science targets per hour. In more than three years of operations at Palomar Observatory, it has been quite successful, producing technology that is being adapted by other AO systems and robotic telescope projects, as well as several high impact scientific publications. Now, Robo-AO has been selected to take over operation of the Kitt Peak National Observatory 2.1m telescope. This will give Robo-AO KP the opportunity to pursue multiple science programs consisting of several thousand targets each during the three years it will be on the telescope. One-sixth of the observing time will be allocated to the US community through the NOAO TAC process. This presentation will discuss the process adapting Robo-AO to the KPNO 2.1m telescope, the plans for integration and initial operations, and the science operations and programs to be pursued.

  10. LDEF (Postflight), AO201 : Interplanetary Dust Experiment, Tray B12

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO201 : Interplanetary Dust Experiment, Tray B12 The postflight photograph shows little change of the exposed surfaces when compared with the prelaunch photograph. Although not noticable in the photograph, a light coating of contamination was seen on all experiment surfaces in this location. The difference in colors of the IDE detectors, located on the right hand mounting plate, is a result of the reflected surroundings and not related to space exposure. A close observation of the detector surfaces reveal that some damage has occured from meteroid and/or debris impacts. One impact crater can be seen, upper right quadrant, on the detector located in the sixth (6th) row down from the top and the fifth (5th) row from the right. Other impacts, smaller in size, show as small white dots on the detector surface. The solar sensor seems to have changed little, if any. However, the color of the solar array baseplate, showing indications of contamination, appears to be darker than the detector mounting plate. The center section cover plate shows little change when compared with the pre-launch photograph. However, during inspection, a light coat of the brown contamination has been observed on all surfaces. The color of the bonding material (RTV) used to secure several thin specimen, sapphire, to individual mounting plates has changed from pink to gold. At one location, that of a single specimen, the bonding material is more gray than gold in color. This has been attributed to the specimen being considerably thicker. The EPDS thermal cover in the right hand side of the tray shows a light coating of brown contamination on the Chemglaze II A-276 white paint.

  11. Multi-conjugate AO for the European Solar Telescope

    NASA Astrophysics Data System (ADS)

    Montilla, I.; Béchet, C.; Le Louarn, M.; Tallon, M.; Sánchez-Capuchino, J.; Collados Vera, M.

    2012-07-01

    The European Solar Telescope (EST) will be a 4-meter diameter world-class facility, optimized for studies of the magnetic coupling between the deep photosphere and upper chromosphere. It will specialize in high spatial resolution observations and therefore it has been designed to incorporate an innovative built-in Multi-Conjugate Adaptive Optics system (MCAO). It combines a narrow field high order sensor that will provide the information to correct the ground layer and a wide field low order sensor for the high altitude mirrors used in the MCAO mode. One of the challenging particularities of solar AO is that it has to be able to correct the turbulence for a wide range of observing elevations, from zenith to almost horizon. Also, seeing is usually worse at day-time, and most science is done at visible wavelengths. Therefore, the system has to include a large number of high altitude deformable mirrors. In the case of the EST, an arrangement of 4 high altitude DMs is used. Controlling such a number of mirrors makes it necessary to use fast reconstruction algorithms to deal with such large amount of degrees of freedom. For this reason, we have studied the performance of the Fractal Iterative Method (FriM) and the Fourier Transform Reconstructor (FTR), to the EST MCAO case. Using OCTOPUS, the end-to-end simulator of the European Southern Observatory, we have performed several simulations with both algorithms, being able to reach the science requirement of a homogeneous Strehl higher that 50% all over the 1 arcmin field of view.

  12. LDEF (Prelaunch), AO038 : Interstellar Gas Experiment, Tray H09

    NASA Technical Reports Server (NTRS)

    1984-01-01

    LDEF (Prelaunch), AO038 : Interstellar Gas Experiment, Tray H09 The prelaunch photograph was taken in SAEF II at KSC prior to installation of the Interstellar Gas Experiment on the LDEF. The prelaunch photograph provides a view of the Interstellar Gas Experiment (IGE) hardware and shows the orientation of two (2) experiment canister housings mounted in a twelve (12) inch deep end tray. The experiment utilizes seven (7) canisters containing high-purity beryllium copper collecting foils, three (3) located in peripheral trays and four (4) located in trays on the space end of the LDEF, to meet experiment objectives. The active portion of the experiment consist of canister electronic timing devices and pyrotechnic cutters that control the exposure time of each collector foil. An electronic voltage multiplier system provides a bias voltage to the grid network located above the beryllium copper collecting foils.The batteries and the electronics are housed beneath the experiment baseplate facing the LDEF interior. The white painted surface area within the LDEF tray provides the optical properties required to maintain the experiment components within temperature limits. The two (2) rectangular openings in opposite corners of the experiment baseplate provide the mountings for the grid voltage box and for the ground support equipment test connectors. A white grid voltage box, mounted on the side of each canister housing, provides the termination point for the cables running from the power supply located beneath the baseplate. The canister housing is a welded aluminum structure with aluminum mounting flanges. The experiment components are assembled using non-magnetic stainless steel fasteners. The aluminum housing cover, removed prior to flight, protects experiment components from damage and large particle contamination during ground handling.

  13. LDEF (Prelaunch), AO038 : Interstellar Gas Experiment, Tray H06

    NASA Technical Reports Server (NTRS)

    1984-01-01

    LDEF (Prelaunch), AO038 : Interstellar Gas Experiment, Tray H06 The prelaunch photograph was taken in SAEF II at KSC prior to installation of the Interstellar Gas Experiment on the LDEF. The prelaunch photograph provides a view of the Interstellar Gas Experiment (IGE) hardware and shows the orientation of two (2) experiment canister housings mounted in a twelve (12) inch deep end tray. The experiment utilizes seven (7) canisters containing high-purity beryllium copper collecting foils, three (3) located in peripheral trays and four (4) located in trays on the space end of the LDEF, to meet experiment objectives. The active portion of the experiment consist of canister electronic timing devices and pyrotechnic cutters that control the exposure time of each collector foil. An electronic voltage multiplier system provides a bias voltage to a wire mesh grid located above the beryllium copper collecting foils.The batteries and the electronics are housed beneath the experiment baseplate facing the LDEF interior. The white painted surface area within the LDEF tray provides the optical properties required to maintain the experiment components within temperature limits. The two (2) rectangular openings in opposite corners of the experiment baseplate provide the mountings for the grid voltage box and for the ground support equipment test connectors. A white grid voltage box, mounted on the side of each canister housing, provides the termination point for the cables running from the power supply located beneath the baseplate. The canister housing is a welded aluminum structure with aluminum mounting flanges. The experiment components are assembled using non-magnetic stainless steel fasteners. The aluminum housing cover, removed prior to flight, protects experiment components from damage and large particle contamination during ground handling.

  14. LDEF (Prelaunch), AO038 : Interstellar Gas Experiment, Tray E12

    NASA Technical Reports Server (NTRS)

    1984-01-01

    LDEF (Prelaunch), AO038 : Interstellar Gas Experiment, Tray E12 The prelaunch photograph provides a view of the Interstellar Gas Experiment (IGE) hardware and shows the orientation of two (2) experiment canister housings mounted in a twelve (12) inch deep peripheral tray. The experiment utilizes seven (7) canisters containing high-purity beryllium copper collecting foils, three (3) located in peripheral trays and four (4) located in trays on the space end of the LDEF, to meet experiment objectives. The active portion of the experiment consist of canister electronic timing devices and pyrotechnic cutters that control the exposure time of each collector foil. An electronic voltage multiplier system provides a bias voltage to the grid network located above the beryllium copper collecting foils.The batteries and the electronics are housed beneath the experiment baseplate facing the LDEF interior. The white painted surface area within the LDEF tray provides the optical properties required to maintain the experiment components within temperature limits. The two (2) rectangular openings in opposite corners of the experiment baseplate provide the mountings for the ground support equipment test connectors. A white grid voltage connector box, mounted on the side of each canister housing, provides the termination point for the cables running from the grid voltage box beneath the baseplate. The canister housing is a welded aluminum structure with aluminum mounting flanges. The experiment components are assembled using non-magnetic stainless steel fasteners. The aluminum housing cover, removed prior to flight, protects experiment components from damage and large particle contamination during ground handling.

  15. LDEF (Postflight), AO038 : Interstellar Gas Experiment, Tray H06

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO038 : Interstellar Gas Experiment, Tray H06 The post landing photograph was taken from the Orbiter's cargo bay access hatch during post landing operations to prepare the Orbiter for the ferry flight from the Dryden Flight Research Center to the Kennedy Space Center. A very light contamination stain is present on the experiment tray flanges and on the most of the visible LDEF structure. The exception being a much darker stain on the structure adjacent to thermal covers that provide venting for the LDEF interior. The paint dot adjacent to the thermal cover vent area is heavily coated with the brown contamination stain while the paint dot adjacent to the center end cover plate has a very light coating. The color of the white thermal control paint on the IGE has changed and now varies from offwhite to a dark brown. The darker brown areas on the experiment baseplate, around the grid voltage cable connectors, appear to have come from contaminants flowing from inside the LDEF. A dark stain area can be seen on the tray's lower sidewall and in the upper left corner of the tray. A lighter stain coats portions of the experiment baseplate and the outside of the canister housing. A beryllium copper collector foil is clearly visible within the canister housings as are the baffles and reflected light from the fine wire mesh grid near the top of the canister housing. Due to an experi- ment system malfunction, the canister collector foils that are visible were exposed for the total mission.

  16. Bringing the Visible Universe into Focus with Robo-AO

    PubMed Central

    Baranec, Christoph; Riddle, Reed; Law, Nicholas M.; Ramaprakash, A.N.; Tendulkar, Shriharsh P.; Bui, Khanh; Burse, Mahesh P.; Chordia, Pravin; Das, Hillol K.; Davis, Jack T.C.; Dekany, Richard G.; Kasliwal, Mansi M.; Kulkarni, Shrinivas R.; Morton, Timothy D.; Ofek, Eran O.; Punnadi, Sujit

    2013-01-01

    The angular resolution of ground-based optical telescopes is limited by the degrading effects of the turbulent atmosphere. In the absence of an atmosphere, the angular resolution of a typical telescope is limited only by diffraction, i.e., the wavelength of interest, λ, divided by the size of its primary mirror's aperture, D. For example, the Hubble Space Telescope (HST), with a 2.4-m primary mirror, has an angular resolution at visible wavelengths of ~0.04 arc seconds. The atmosphere is composed of air at slightly different temperatures, and therefore different indices of refraction, constantly mixing. Light waves are bent as they pass through the inhomogeneous atmosphere. When a telescope on the ground focuses these light waves, instantaneous images appear fragmented, changing as a function of time. As a result, long-exposure images acquired using ground-based telescopes - even telescopes with four times the diameter of HST - appear blurry and have an angular resolution of roughly 0.5 to 1.5 arc seconds at best. Astronomical adaptive-optics systems compensate for the effects of atmospheric turbulence. First, the shape of the incoming non-planar wave is determined using measurements of a nearby bright star by a wavefront sensor. Next, an element in the optical system, such as a deformable mirror, is commanded to correct the shape of the incoming light wave. Additional corrections are made at a rate sufficient to keep up with the dynamically changing atmosphere through which the telescope looks, ultimately producing diffraction-limited images. The fidelity of the wavefront sensor measurement is based upon how well the incoming light is spatially and temporally sampled1. Finer sampling requires brighter reference objects. While the brightest stars can serve as reference objects for imaging targets from several to tens of arc seconds away in the best conditions, most interesting astronomical targets do not have sufficiently bright stars nearby. One solution is to focus a high-power laser beam in the direction of the astronomical target to create an artificial reference of known shape, also known as a 'laser guide star'. The Robo-AO laser adaptive optics system2,3 employs a 10-W ultraviolet laser focused at a distance of 10 km to generate a laser guide star. Wavefront sensor measurements of the laser guide star drive the adaptive optics correction resulting in diffraction-limited images that have an angular resolution of ~0.1 arc seconds on a 1.5-m telescope. PMID:23426078

  17. Bringing the visible universe into focus with Robo-AO.

    PubMed

    Baranec, Christoph; Riddle, Reed; Law, Nicholas M; Ramaprakash, A N; Tendulkar, Shriharsh P; Bui, Khanh; Burse, Mahesh P; Chordia, Pravin; Das, Hillol K; Davis, Jack T C; Dekany, Richard G; Kasliwal, Mansi M; Kulkarni, Shrinivas R; Morton, Timothy D; Ofek, Eran O; Punnadi, Sujit

    2013-01-01

    The angular resolution of ground-based optical telescopes is limited by the degrading effects of the turbulent atmosphere. In the absence of an atmosphere, the angular resolution of a typical telescope is limited only by diffraction, i.e., the wavelength of interest, λ, divided by the size of its primary mirror's aperture, D. For example, the Hubble Space Telescope (HST), with a 2.4-m primary mirror, has an angular resolution at visible wavelengths of ~0.04 arc seconds. The atmosphere is composed of air at slightly different temperatures, and therefore different indices of refraction, constantly mixing. Light waves are bent as they pass through the inhomogeneous atmosphere. When a telescope on the ground focuses these light waves, instantaneous images appear fragmented, changing as a function of time. As a result, long-exposure images acquired using ground-based telescopes--even telescopes with four times the diameter of HST--appear blurry and have an angular resolution of roughly 0.5 to 1.5 arc seconds at best. Astronomical adaptive-optics systems compensate for the effects of atmospheric turbulence. First, the shape of the incoming non-planar wave is determined using measurements of a nearby bright star by a wavefront sensor. Next, an element in the optical system, such as a deformable mirror, is commanded to correct the shape of the incoming light wave. Additional corrections are made at a rate sufficient to keep up with the dynamically changing atmosphere through which the telescope looks, ultimately producing diffraction-limited images. The fidelity of the wavefront sensor measurement is based upon how well the incoming light is spatially and temporally sampled. Finer sampling requires brighter reference objects. While the brightest stars can serve as reference objects for imaging targets from several to tens of arc seconds away in the best conditions, most interesting astronomical targets do not have sufficiently bright stars nearby. One solution is to focus a high-power laser beam in the direction of the astronomical target to create an artificial reference of known shape, also known as a 'laser guide star'. The Robo-AO laser adaptive optics system, employs a 10-W ultraviolet laser focused at a distance of 10 km to generate a laser guide star. Wavefront sensor measurements of the laser guide star drive the adaptive optics correction resulting in diffraction-limited images that have an angular resolution of ~0.1 arc seconds on a 1.5-m telescope. PMID:23426078

  18. LDEF (Flight), AO038 : Interstellar Gas Experiment, Tray F06

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO038 : Interstellar Gas Experiment, Tray F06 The flight photograph was taken from the Orbiter aft flight deck during the LDEF retrieval. The OMS pod and a small part of the aft bulkhead in the Orbiter's cargo bay can be seen along the left side of the photograph. The three (3) black rectangles on the OMS pod are locations where thermal protection tiles were lost during the Orbiters ascent to orbit. During the LDEF mission, the F06 experiment tray surface was at an angle of approximately eighty-two (82) degrees to the orbital velocity vector and therefore exposed to a higher atomic oxygen flux than if parallel with the velocity vector. The white paint dots and experiment tray clamps along the upper edge of the tray appear to be clean. However, a brown stain is present on the white paint dots and experiment tray clamps along the lower edge of the tray. The color of the white thermal control paint on the IGE has changed from white to differing shades of brown. The brown stain on the tray sidewalls and all experiment hardware appears to be a product of contamination and the space environment. A hand print, not visible in the prelaunch photograph, can be seen on the baseplate in the lower half of the experiment tray. The white dot near the lower corner of the end sidewall is a reflection of the GSE test connector located in the lower left corner of the baseplate. The two (2) white dots on the experiment baseplate, near the left end of the tray, appear to be imperfections in the photograph since they were not observed during post-flight inspection..The insulation on the grid voltage cable that was transparent prior to launch is now a light tan color. The lighting and camera angle provide a clear view of the baffles located interior and near the upper edges of the canister housing. The baffles seem to be relatively clean of the brown contamination.

  19. Patterns of Impairments in AOS and Mechanisms of Interaction between Phonological and Phonetic Encoding

    ERIC Educational Resources Information Center

    Laganaro, Marina

    2012-01-01

    Purpose: One reason why the diagnosis of apraxia of speech (AOS) and its underlying impairment are often debated may lie in the fact that most patients do not display pure patterns of AOS. Mixed patterns are clearly acknowledged at other levels of impairment (e.g., lexical-semantic and lexical-phonological), and they have contributed to debate…

  20. Patterns of Impairments in AOS and Mechanisms of Interaction between Phonological and Phonetic Encoding

    ERIC Educational Resources Information Center

    Laganaro, Marina

    2012-01-01

    Purpose: One reason why the diagnosis of apraxia of speech (AOS) and its underlying impairment are often debated may lie in the fact that most patients do not display pure patterns of AOS. Mixed patterns are clearly acknowledged at other levels of impairment (e.g., lexical-semantic and lexical-phonological), and they have contributed to debate…

  1. MagAO: Status and on-sky performance of the Magellan adaptive optics system

    NASA Astrophysics Data System (ADS)

    Morzinski, Katie M.; Close, Laird M.; Males, Jared R.; Kopon, Derek; Hinz, Phil M.; Esposito, Simone; Riccardi, Armando; Puglisi, Alfio; Pinna, Enrico; Briguglio, Runa; Xompero, Marco; Quirós-Pacheco, Fernando; Bailey, Vanessa; Follette, Katherine B.; Rodigas, T. J.; Wu, Ya-Lin; Arcidiacono, Carmelo; Argomedo, Javier; Busoni, Lorenzo; Hare, Tyson; Uomoto, Alan; Weinberger, Alycia

    2014-07-01

    MagAO is the new adaptive optics system with visible-light and infrared science cameras, located on the 6.5-m Magellan "Clay" telescope at Las Campanas Observatory, Chile. The instrument locks on natural guide stars (NGS) from 0th to 16th R-band magnitude, measures turbulence with a modulating pyramid wavefront sensor binnable from 28×28 to 7×7 subapertures, and uses a 585-actuator adaptive secondary mirror (ASM) to provide at wavefronts to the two science cameras. MagAO is a mutated clone of the similar AO systems at the Large Binocular Telescope (LBT) at Mt. Graham, Arizona. The high-level AO loop controls up to 378 modes and operates at frame rates up to 1000 Hz. The instrument has two science cameras: VisAO operating from 0.5-1μm and Clio2 operating from 1-5 μm. MagAO was installed in 2012 and successfully completed two commissioning runs in 2012-2013. In April 2014 we had our first science run that was open to the general Magellan community. Observers from Arizona, Carnegie, Australia, Harvard, MIT, Michigan, and Chile took observations in collaboration with the MagAO instrument team. Here we describe the MagAO instrument, describe our on-sky performance, and report our status as of summer 2014.

  2. SCExAO as a precursor to an ELT exoplanet direct imaging instrument

    NASA Astrophysics Data System (ADS)

    Jovanovic, Nemanja; Guyon, Olivier; Martinache, Frantz; Clergeon, Christophe; Singh, Garima; Vievard, Sebastien; Kudo, Tomoyuki; Garrel, Vincent; Norris, Barnaby; Tuthill, Peter; Stewart, Paul; Huby, Elsa; Perrin, Guy; Lacour, Sylvestre

    2013-12-01

    The Subaru Coronagraphic Extreme AO (SCExAO) instrument consists of a high performance Phase Induced Amplitude Apodisation (PIAA) coronagraph combined with an extreme Adaptive Optics (AO) system operating in the near-infrared (H band). The extreme AO system driven by the 2000 element deformable mirror will allow for Strehl ratios>90% to be achieved in the H-band when it goes closed loop. This makes the SCExAO instrument a powerful platform for high contrast imaging down to angular separations of the order of 1 lambda/D and an ideal testbed for exploring coronagraphic techniques for ELTs. In this paper we report on the recent progress in regards to the development of the instrument, which includes the addition of a visible bench that makes use of the light at shorter wavelengths not currently utilized by SCExAO and closing the loop on the tip/tilt wavefront sensor. We will also discuss several exciting guest instruments which will expand the capabilities of SCExAO over the next few years; namely CHARIS which is a integral field spectrograph as well as VAMPIRES, a visible aperture masking experiment based on polarimetric analysis of circumstellar disks. In addition we will elucidate the unique role extreme AO systems will play in enabling high precision radial velocity spectroscopy for the detection of small companions.

  3. Robo-AO: Initial results from the first autonomous laser guide star adaptive optics instrument

    NASA Astrophysics Data System (ADS)

    Riddle, R. L.; Baranec, C.; Law, N. M.; Ramaprakash, A. N.; Tendulkar, S.; Hogstrom, K.; Bui, K.; Burse, M.; Chordia, P.; Das, H.; Dekany, R.; Kulkarni, S.; Punnadi, S.; Smith, R.

    2014-12-01

    Large surveys are discovering thousands of objects which require further characterization at high angular resolution. The demands on space-based observatories and large telescopes with AO systems leave them generally unavailable for large high angular resolution surveys. To address this gap, we have developed Robo-AO, the first robotic laser AO system, as an economical and efficient imaging instrument for 1-3 m class telescopes. Observations of over 200 stellar objects per night have routinely been performed, with target-to-target observation overheads of less than 1.5 minutes. Scientific programs of several thousands of targets can be executed in mere weeks, and Robo-AO has already completed the three largest AO surveys to date.

  4. LDEF (Prelaunch), AO201 : Interplanetary Dust Experiment, Tray B12

    NASA Technical Reports Server (NTRS)

    1984-01-01

    LDEF (Prelaunch), AO201 : Interplanetary Dust Experiment, Tray B12 The prelaunch photograph shows the six (6) inch deep Interplanetary Dust Experiment (IDE) master control tray. The tray has three (3) mounting/cover plates elevated on fiberglass stand-offs to provide clearance and protection for hardware and electronics located underneath. The stand-offs also raise the plates to a level that minimizes shading of detectors by the tray sidewalls. The mounting plate located at the left hand end of the tray is populated with eighty (80) metaloxide-silicon (MOS) capacitor-type impact sensors and one (1) solar sensor that is located approximately in the center of the mounting plate. The IDE sensors are two (2) inch diameter MOS capacitor structures approximately 250 um thick. The detectors are formed by growing either 0.4um or 1.0um thick silicon oxide, SiO2, layer on the 250um thick, B-doped polished silicon wafer. The top metal contact, the visible surface, was formed by vapor deposition of 1000A of aluminum on the SiO2 surface. Aluminum was also vapor deposited on the backside to form the contact with the silicon substrate. Gold wires are bonded to the front and back aluminum layers for use in connecting the detectors to the circuits. The complete wafers, IDE detectors, are mounted on chromic anodized aluminum frames by bonding the detector backside to the aluminum frame with a space qualified RTV silicon adhesive, de-volatized RTV-511. The difference in colors of the detectors is caused by reflections in the metallized surfaces. A reflection of one of the technicians is visible in the three (3) rows of detector on the left hand side of the mounting plate. The solar sensor, located at the mounting plate center, consist of four (4) silicon solar cells connected in series and associated circuity bonded to an aluminum baseplate. The solar sensor registered each orbital sunrise independant of LDEF orientation at the time of sunrise. When IDE solar sensor data from the six (6) orthogonal faces of the LDEF was correlated, the Interplanetary Dust Experiment clock could be precisely calibrated. The center 1/3rd tray cover is a chromic anodized aluminum plate that protects the IDE data conditioning and control electronics mounted underneath. The cover plate also serves as a mounting platform for ten (10) individual specimen holders provided by one of the IDE investigators.The material specimen, consisting of germanium, sapphire and zinc sulfide of different sizes, shapes and colors, are bonded to the specimen holders with an RTV adhesive. The specimen holders are attached to the cover plate with stainless steel non-magnetic fasteners. The 1/3rd tray cover plate in the right hand end of the experiment tray is an aluminum plate painted white with Chemglaze II A-276 paint and used as a thermal cover for the Experiment Power and Data System (EPDS). The EPDS is a system provided by the LDEF Project Office that processes and stores, on magnetic tape, the orbital experiment and housekeeping data from six (6) experiment locations on the LDEF.

  5. L'univers clos de Stephen Hawking.

    NASA Astrophysics Data System (ADS)

    Andrillat, H.

    Einstein had curved space, Hawking will curve time. Hawking's universe is a closed model, a 4-sphere, which encloses its own space and its own time. Nothing exists outside and without any time overlapping this 4-sphere, it cannot have a beginning, an evolution or an end. It only is. But such an absolute existence of this type of universe implies that its 3-dimensional sclices - which are our physical space - cannot have the same absolute state of being. Thus, they are necessarily transitory, with a beginning and an end, in time which is the 4th remaining dimension of the 4-sphere. Hawking absolute universe is the cause of time.

  6. [Activities of Psychology Dept., California Univ.

    NASA Technical Reports Server (NTRS)

    Bridgeman, Bruce

    1998-01-01

    We have completed two studies during the grant period, with manuscripts published or ready for submission for publication: (1) Dual adaptation and adaptive generalization in the human vestibuloocular reflex and (2) Frequency vs. acceleration specificity in human VOR adaptation. In the 1st study two studies examined the possibility that rotational VOR plasticity is subject to dual adaptation and adaptive generalization. Subjects in the experimental condition were exposed to an altered visual-vestibular environment for about four minutes every day for five consecutive days. The working hours between these testing sessions constituted re-exposure to the normal visual environment. Thus, subjects were repeatedly adapting and re-adapting to both environments which is a condition designed to produce dual adaptation. In each training session a measure of baseline VOR gain was obtained (in the dark). A small laser spot (the only visual stimulus) was systematically moved in the same direction as the subject's head, but by half the angle of rotation (target/head gain = 0.5). This resulted in adaptation values relativized to the non-adapted gain of each subject. These values were then analyzed using an analysis of variance with day and session (within a day) as factors. In the 2nd study human VOR adaption has been assumed to be frequency specific, despite the fact that the semicircular canals are simulated by rotational acceleration and not frequency per se.

  7. Exotic atoms. [Univ. of Wyoming, Laramie, Wyoming

    SciTech Connect

    Kunselman, R.

    1993-01-01

    The experiments use a solid hydrogen layer to form muonic hydrogen isotopes that escape into vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target has been constructed which exploits muonic atom emission in order to learn more about the energy dependence of transfer and muon molecular formation.

  8. Progress report. [Dept. of Chemistry, Howard Univ

    SciTech Connect

    Not Available

    1980-01-01

    CN radicals produced in the collisions C + NO and C + N/sub 2/O were studied by laser-induced spectroscopy. Effects of an excimer laser on a CS/sub 2/ beam were also observed. The work performed is only summarized here; completed work has been published. (RWR)

  9. Closeup of CO172AO8, showing section of building 211 closest to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Close-up of CO-172-AO-8, showing section of building 211 closest to building 206. - Fitzsimons General Hospital, Quartermaster's Storehouse, Southwest Corner of East I Avenue & North Twelfth Street, Aurora, Adams County, CO

  10. Status update and closed-loop performance of the Magellan adaptive optics VisAO camera

    NASA Astrophysics Data System (ADS)

    Kopon, Derek; Close, Laird M.; Males, Jared; Gasho, Victor; Morzinski, Katie; Follette, Katherine

    2012-07-01

    We present laboratory results of the closed-loop performance of the Magellan Adaptive Optics (AO) Adaptive Secondary Mirror (ASM), pyramid wavefront sensor (PWFS), and VisAO visible adaptive optics camera. The Magellan AO system is a 585-actuator low-emissivity high-throughput system scheduled for first light on the 6.5 meter Magellan Clay telescope in November 2012. Using a dichroic beamsplitter near the telescope focal plane, the AO system will be able to simultaneously perform visible (500-1000 nm) AO science with our VisAO camera and either 10 ?m or 3-5 ?m science using either the BLINC/MIRAC4 or CLIO cameras, respectively. The ASM, PWS, and VisAO camera have undergone final system tests in the solar test tower at the Arcetri Institute in Florence, Italy, reaching Strehls of 37% in i'-band with 400 modes and simulated turbulence of 14 cm ro at v-band. We present images and test results of the assembled VisAO system, which includes our prototype advanced Atmospheric Dispersion Corrector (ADC), prototype calcite Wollaston prisms for SDI imaging, and a suite of beamsplitters, filters, and other optics. Our advanced ADC performs in the lab as designed and is a 58% improvement over conventional ADC designs. We also present images and results of our unique Calibration Return Optic (CRO) test system and the ASM, which has successfully run in closedloop at 1kHz. The CRO test is a retro reflecting optical test that allows us to test the ASM off-sky in close-loop using an artificial star formed by a fiber source.

  11. Decolorization of the AO24 azo dye and reduction of toxicity and genotoxicity in trickling biofilters.

    PubMed

    Garzóón-Zúñga, Marco A; Sandoval-Villasana, Ana M; Moeller-Chávez, Gabriela E

    2011-02-01

    Acid Orange 24 (AO24) dye was degraded in a trickling biofilter packed with peat and wood chips and inoculated with biomass from a petrochemical industry wastewater system. Different operating strategies were tested; in the first stage, two biofilters were operated independently--one non-aerated biofilter (passive) and the other with aeration-subsequently, the systems were operated serially, and effluent from the non-aerated biofilter was fed to the biofilter with aeration. This treatment train was used to test three different filtration velocities--0.141, 0.282, and 0.423 m/d. The results show that, when operating the systems with a dye charge of 0.035 kg AO24 m2/d and treating the effluent in a single step, good removal efficiencies of AO24 (95 and 89%), COD (63 and 53%), and acute toxicity (63 and 78%) were obtained in both biofilters (with and without air), although mutagenic and potentially carcinogenic intermediary compounds were not removed, because genotoxicity exhibits values higher than 2.0 units for the mutation rate. When using the non-aerated biofilter/aerated biofilter treatment train, it is possible to treat a dye charge 3 times greater (0.106 kg AO24 m2/d) and efficiently remove 98% AO24, 76% COD, 100% acute toxicity, and 100% genotoxicity, which indicates that, with this biological system, an advanced degree of biotransformation and mineralization of the azo dye AO24 is achieved. PMID:21449472

  12. Importance of combined winter and summer Arctic Oscillation (AO) on September sea ice extent

    NASA Astrophysics Data System (ADS)

    Ogi, Masayo; Rysgaard, Søren; Barber, David G.

    2016-03-01

    We examine the influence of winter and summer Arctic Oscillation (AO) on variations in the September Arctic sea ice extent (SIE). The winter and summer atmospheric patterns associated with year-to-year variations and detrended September SIE correlate with the positive winter AO and the negative summer AO, respectively. However, the interannual variations of winter and summer AO indices after 2007 are more weakly connected with year-to-year variations in the September SIE. Since 2007, the surface air temperatures over the Beaufort, Chukchi and East Siberian Seas are related to the interannual variations of the September SIE. Recent summer atmospheric patterns associated with the September SIE correlate with the summer AO pattern, but the summer anticyclonic circulation over the Arctic favours the recent low September SIE more than the seesaw pattern between mid- and high- latitudes. Recent winters’ positive AO have not contributed to the recent low September SIE because winter anticyclonic circulation over northern Eurasia is more directly connected with recent September SIE.

  13. Te Ao Kori as Expressive Movement in Aotearoa New Zealand Physical Education Teacher Education (PETE): A Narrative Account

    ERIC Educational Resources Information Center

    Legge, Maureen

    2011-01-01

    A unique aspect of Aotearoa/New Zealand physical education is the inclusion of Maori culture in the form of te ao kori. Te ao kori translates to mean the world of movement and is represented by the interpretation of indigenous movement, games and pastimes. Participation in te ao kori means the sports-based normative frame of reference for physical…

  14. Te Ao Kori as Expressive Movement in Aotearoa New Zealand Physical Education Teacher Education (PETE): A Narrative Account

    ERIC Educational Resources Information Center

    Legge, Maureen

    2011-01-01

    A unique aspect of Aotearoa/New Zealand physical education is the inclusion of Maori culture in the form of te ao kori. Te ao kori translates to mean the world of movement and is represented by the interpretation of indigenous movement, games and pastimes. Participation in te ao kori means the sports-based normative frame of reference for physical…

  15. Toward an experimental validation of new AO concepts for future E-ELT instrumentation

    NASA Astrophysics Data System (ADS)

    El Hadi, K.; Fusco, T.; Le Roux, B.

    2012-07-01

    For the last few years, LAM has been carrying out several R&D activities in Adaptive Optics (AO) instrumentation for Extremely Large Telescopes (ELTs). In the European ELT framework, a multi-purpose AO bench is developed to allow the experimental validation of new instrumental concepts dedicated to the next generation of ELTs. It is based on the use of a Shack-Hartmann wave-front sensor in front of a 140 actuators micro-deformable mirror (Boston Micromachines), dedicated to “low orders” modes, while a Pyramid wave-front sensor (PWFS) will be combined to a Liquid Crystal Spatial Light Modulator for “high orders” correction. Both systems could be merged in a two stages AO concept allowing to study the coupling of a telescope pre-correction using a dedicated large M4 deformable mirror and a post focal high order AO system. Analysis and optimisation of the spatial and temporal splits of the AO correction between the two systems is therefore essential. Finally, we will use the world’s fastest and most sensitive camera system OCAM (developed at LAM) coupled with the pyramid , to demonstrate the concept of a fast and hyper-sensitive PWFS (up to 100x100 sub-pupils) dedicated to the first generation instruments for ELTs.

  16. Optical-X-ray Observations of BL Lacertae Object AO 0235+164

    NASA Astrophysics Data System (ADS)

    Howard, Emily S.; Webb, James R.; Balonek, Thomas J.; McGrath, Elizabeth; Shrader, Chris R.

    1998-11-01

    The BL Lacertea object AO 0235+164 dramatically increased in brightness on October 20, 1997. This outburst was observed with the 1 meter SARA (Southeastern Association for Research in Astronomy) telescope located at Kitt Peak National Observatory (KPNO) located southwest of Tucson, Arizona. As a result of our observations, AO 0235+164 was also observed during the outbust by the Rossi X-ray Timing Experiment (RXTE) and Foggy Bottom Observaotry, Colgate Univserity, New York as a part of a Target of Opportunity (TOO) program. We present here the historical lightcurve of AO 0235+164, Optical observations during the ourtburst from the SARA and Foggy Bottom Observatories and X-ray observations from RXTE. Also, we present multifrequency data during this period and compare the variability of the Optical and X-ray bands.

  17. Up-Regulated Expression of AOS-LOXa and Increased Eicosanoid Synthesis in Response to Coral Wounding

    PubMed Central

    Lõhelaid, Helike; Teder, Tarvi; Tõldsepp, Kadri; Ekins, Merrick; Samel, Nigulas

    2014-01-01

    In octocorals, a catalase–like allene oxide synthase (AOS) and an 8R-lipoxygenase (LOX) gene are fused together encoding for a single AOS-LOX fusion protein. Although the AOS-LOX pathway is central to the arachidonate metabolism in corals, its biological function in coral homeostasis is unclear. Using an acute incision wound model in the soft coral Capnella imbricata, we here test whether LOX pathway, similar to its role in plants, can contribute to the coral damage response and regeneration. Analysis of metabolites formed from exogenous arachidonate before and after fixed time intervals following wounding indicated a significant increase in AOS-LOX activity in response to mechanical injury. Two AOS-LOX isoforms, AOS-LOXa and AOS-LOXb, were cloned and expressed in bacterial expression system as active fusion proteins. Transcription levels of corresponding genes were measured in normal and stressed coral by qPCR. After wounding, AOS-LOXa was markedly up-regulated in both, the tissue adjacent to the incision and distal parts of a coral colony (with the maximum reached at 1 h and 6 h post wounding, respectively), while AOS-LOXb was stable. According to mRNA expression analysis, combined with detection of eicosanoid product formation for the first time, the AOS-LOX was identified as an early stress response gene which is induced by mechanical injury in coral. PMID:24551239

  18. Repruducibility of tronzo and ao/asif classifications for transtrochanteric fractures

    PubMed Central

    Behrendt, Christian; Faleiro, Thiago Batista; Schulz, Renata Da Silva; Silva, Bianca Ortiz Da; Paula, Erivaldo Queiróz De

    2014-01-01

    Objective: To assess the reproducibility of Tronzo and AO/ASIF classifications for transtrochanteric fractures, in order to determine the most appropriate classification for clinical application, and to evaluate the influence of the level of experience of the observers in the agreement between evaluations. Methods: We selected 30 radiographic images of transtrochanteric fractures of the femur, which were presented to two groups of observers, one formed by expert physicians and the other by resident physicians. Results: When evaluated together, Tronzo classification obtained a Kappa value of 0.44. The same classification assessed by the expert group obtained a value of 0.46, while the group of residents' value was 0.44. Evaluating the AO/ASIF classification of the complete pool analysis the value found was 0.42. For the same classification, analyzed by the expert group, obtained a value of 0.41, and by the group of residents, the Kappa value achieved was 0.42. However, when analyzed in its simplified form, the AO/ASIF classification obtained Kappa values of 0.70 (pooled analysis), 0.68 (experts) and 0.72 (residents), considered concurrent. Conclusion: The AO/ASIF simplified classification showed substantial reproducibility and is, therefore, recommended as the most suitable for clinical application. The level of experience of the observers did not influence significantly the agreement between evaluations. Level of Evidence III, Diagnostic Study - Investigating a Diagnostic Test. PMID:25328437

  19. GPS-Based Navigation And Orbit Determination for the AMSAT AO-40 Satellite

    NASA Technical Reports Server (NTRS)

    Davis, George; Moreau, Michael; Carpenter, Russell; Bauer, Frank

    2002-01-01

    The AMSAT OSCAR-40 (AO-40) spacecraft occupies a highly elliptical orbit (HEO) to support amateur radio experiments. An interesting aspect of the mission is the attempted use of GPS for navigation and attitude determination in HEO. Previous experiences with GPS tracking in such orbits have demonstrated the ability to acquire GPS signals, but very little data were produced for navigation and orbit determination studies. The AO-40 spacecraft, flying two Trimble Advanced Navigation Sensor (TANS) Vector GPS receivers for signal reception at apogee and at perigee, is the first to demonstrate autonomous tracking of GPS signals from within a HEO with no interaction from ground controllers. Moreover, over 11 weeks of total operations as of June 2002, the receiver has returned a continuous stream of code phase, Doppler, and carrier phase measurements useful for studying GPS signal characteristics and performing post-processed orbit determination studies in HEO. This paper presents the initial efforts to generate AO-40 navigation solutions from pseudorange data reconstructed from the TANS Vector code phase, as well as to generate a precise orbit solution for the AO-40 spacecraft using a batch filter.

  20. The Subaru Coronagraphic Extreme AO High Speed and High Sensitivity Wavefront Sensors

    NASA Astrophysics Data System (ADS)

    Clergeon, Christophe; Guyon, O.; Martinache, F.; Veran, J.; Correia, C.; Garrel, V.; Jovanovic, N.

    2013-01-01

    The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system uses advanced coronagraphic technique for high contrast imaging of exoplanets and disks as close as 1 lambda/D from the host star. In addition to unusual optics, achieving high contrast at this small angular separation requires a wavefront sensing and control architecture which is optimized for exquisite control and calibration of low order aberrations. To complement the current near-IR wavefront control system driving a single MEMS type deformable mirror mounted on a tip-tilt mount, two high order and high sensitivity visible wavefront sensors have been integrated to SCEXAO: - a non modulated Pyramid wavefront sensor (CHEOPS) which is a sensitivity improvement over modulated Pyramid systems now used in high performant astronomical AO, - a non linear wavefront sensor designed in 2012 by Subaru Telescope with the collaboration of the NRC-CNRC which is expected to improve significantly the achieved sensitivity of low order aberations measurements. I will present the Cheops on sky results acquired during last SCEXAO run (November 2012) downstream the Subaru AO188 AO system and then introduce its primary laboratory performances comparison with the first built non linear curvature wavefront sensor.

  1. Performance of a MEMS-based AO-OCT system using Fourier Reconstruction

    SciTech Connect

    Evans, J; Zawadzki, R; Jones, S; Olivier, S; Werner, J S

    2009-01-21

    Adaptive optics (AO) and optical coherence tomography (OCT) are powerful imaging modalities that, when combined, can provide high-resolution (3.5 {micro}m isotropic), 3-D images of the retina. The AO-OCT system at UC Davis has demonstrated the utility of this technology for microscopic, volumetric, in vivo retinal imaging. The current system uses an AOptix bimorph deformable mirror (DM) for low-order, high-stroke correction and a 140-actuator Boston Micromachines DM for high-order correction. Developments to improve performance or functionality of the instrument are on-going. Based on previous work in system characterization we have focused on improved AO control. We present preliminary results and remaining challenges for a newly implemented Fourier transform reconstructor (FTR). The previously reported error budget analysis is also reviewed and updated, with consideration of how to improve both the amount of residual error and the robustness of the system. Careful characterization of the AO system will lead to improved performance and inform the design of future systems.

  2. 76 FR 4726 - Avaya Global Services, AOS Service Delivery, Worldwide Services Group, Including Workers Whose...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-26

    .... The notice was published in the Federal Register on November 8, 2010 (75 FR 68622). At the request of... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Employment and Training Administration Avaya Global Services, AOS Service Delivery, Worldwide Services...

  3. Effects of adrenergic agents on the expression of zebrafish (Danio rerio) vitellogenin Ao1

    SciTech Connect

    Yin Naida; Jin Xia; He Jiangyan; Yin Zhan

    2009-07-01

    Teleost vitellogenins (VTGs) are large multidomain apolipoproteins, traditionally considered to be estrogen-responsive precursors of the major egg yolk proteins, expressed and synthesized mainly in hepatic tissue. The inducibility of VTGs has made them one of the most frequently used in vivo and in vitro biomarkers of exposure to estrogen-active substances. A significant level of zebrafish vtgAo1, a major estrogen responsive form, has been unexpectedly found in heart tissue in our present studies. Our studies on zebrafish cardiomyopathy, caused by adrenergic agonist treatment, suggest a similar protective function of the cardiac expressed vtgAo1. We hypothesize that its function is to unload surplus intracellular lipids in cardiomyocytes for 'reverse triglyceride transportation' similar to that found in lipid transport proteins in mammals. Our results also demonstrated that zebrafish vtgAo1 mRNA expression in heart can be suppressed by both {alpha}-adrenergic agonist, phenylephrine (PE) and {beta}-adrenergic agonist, isoproterenol (ISO). Furthermore, the strong stimulation of zebrafish vtgAo1 expression in plasma induced by the {beta}-adrenergic antagonist, MOXIsylyl, was detected by Enzyme-Linked ImmunoSorbent Assay (ELISA). Such stimulation cannot be suppressed by taMOXIfen, an antagonist to estrogen receptors. Thus, our present data indicate that the production of teleost VTG in vivo can be regulated not only by estrogenic agents, but by adrenergic signals as well.

  4. Improved tilt sensing in an LGS-based tomographic AO system based on instantaneous PSF estimation

    NASA Astrophysics Data System (ADS)

    Veran, Jean-Pierre

    2013-12-01

    Laser guide star (LGS)-based tomographic AO systems, such as Multi-Conjugate AO (MCAO), Multi-Object AO (MOAO) and Laser Tomography AO (LTAO), require natural guide stars (NGSs) to sense tip-tilt (TT) and possibly other low order modes, to get rid of the LGS-tilt indetermination problem. For example, NFIRAOS, the first-light facility MCAO system for the Thirty Meter Telescope requires three NGSs, in addition to six LGSs: two to measure TT and one to measure TT and defocus. In order to improve sky coverage, these NGSs are selected in a so-called technical field (2 arcmin in diameter for NFIRAOS), which is much larger than the on-axis science field (17x17 arcsec for NFIRAOS), on which the AO correction is optimized. Most times, the NGSs are far off-axis and thus poorly corrected by the high-order AO loop, resulting in spots with low contrast and high speckle noise. Accurately finding the position of such spots is difficult, even with advanced methods such as matched-filtering or correlation, because these methods rely on the knowledge of an average spot image, which is quite different from the instantaneous spot image, especially in case of poor correction. This results in poor tilt estimation, which, ultimately, impacts sky coverage. We propose to improve the estimation of the position of the NGS spots by using, for each frame, a current estimate of the instantaneous spot profile instead of an average profile. This estimate can be readily obtained by tracing wavefront errors in the direction of the NGS through the turbulence volume. The latter is already computed by the tomographic process from the LGS measurements as part of the high order AO loop. Computing such a wavefront estimate has actually already been proposed for the purpose of driving a deformable mirror (DM) in each NGS WFS, to optically correct the NGS spot, which does lead to improved centroiding accuracy. Our approach, however, is much simpler, because it does not require the complication of extra DMs, which would need to be driven in open-loop. Instead, it can be purely implemented in software, does not increase the real-time computational burden significantly, and can still provide a significant improvement in tilt measurement accuracy, and therefore in sky-coverage. In this paper, we illustrate the benefit of this new tilt measurement strategy in the specific case of NFIRAOS, under various observing conditions, in comparison with the more traditional approaches that ignore the instantaneous variations of the NGS spot profiles.

  5. Towards the habitable zone: Direct imaging of extrasolar planets with the Magellan AO system

    NASA Astrophysics Data System (ADS)

    Males, Jared Robert

    One of the most compelling scientific quests ever undertaken is the quest to find life in our Universe somewhere other than Earth. An important piece to this puzzle is finding and characterizing extrasolar planets. This effort, particularly the characterization step, requires the ability to directly image such planets. This is a challenging task---such planets are much fainter than their host stars. One of the major solutions to this problem is Adaptive Optics (AO), which allows us to correct the turbulence in the Earth's atmosphere, and thereby further the hunt for exoplanets with ground based telescopes. The Magellan Adaptive Optics system has recently obtained its first on-sky results at Las Campanas Observatory, marking a significant step forward in the development of high-resolution high-contrast ground-based direct imaging. MagAO includes a visible wavelength science camera, VisAO, which---for the first time---provides diffraction limited imaging, in long exposures, on a large filled-aperture (6.5 m) telescope. In this dissertation we report on the design, development, laboratory testing, and initial on-sky results of MagAO and VisAO, which include the first ground-based image of an exoplanet (beta Pictoris b) with a CCD. We also discuss some of the exciting science planned for this system now that it is operational. We close with an analysis of a new problem in direct imaging: planets orbiting their stars move fast enough in the habitable zone to limit our ability to detect them.

  6. Identification and calibration of the interaction matrix parameters for AO and MCAO systems

    NASA Astrophysics Data System (ADS)

    Neichel, Benoit; Parisot, Amelie; Petit, Cyril; Fusco, Thierry; Rigaut, François

    2012-07-01

    New tomographic Adaptive Optics (AO) concepts require a good knowledge of the system geometry and characteristics. These parameters are used to feed the tomographic reconstructors. In this paper we present a method to precisely identify the parameters required to construct an accurate synthetic set of models such as inuence functions, mis-registrations, directions of analysis or altitude of the DMs. The method is based on a multiparameter t of the interaction matrix. This identication method nds also its application in high contrast AO systems, such as SPHERE : in that case it is used as a diagnostic tool in order to precisely realign the system. The method has been tested and successfully implemented on HOMER, SPHERE and GeMS. Experimental results for these three systems are presented.

  7. The 384-channel prototype of DM Electronics for ELT AO systems

    NASA Astrophysics Data System (ADS)

    Caputa, Kris; Atwood, Jenny; Herriot, Glen; Veran, Jean-Pierre; Spanò, Paolo; Zielinski, Adam

    2014-08-01

    High order AO subsystems of the ELT require technological advancements in the Deformable Mirror (DM) construction and corresponding improvements in the drive electronics. Advanced prototyping is currently under way at NSI-Herzberg to reduce risks of deploying untried technology in the TMT AO subsystem NFIRAOS. We have developed a 96-channel output module and constructed a sub-scale DM Electronics prototype NDME384 with 384 output channels based on 4 such modules. French DM vendor Cilas has fabricated the NFIRAOS DM Breadoboard with 360 piezoelectric actuators in a 60×6 matrix, to demonstrate the DM technology to be deployed in NFIRAOS wavefront correctors. We present the results of testing our NDME384 prototype while driving the NFIRAOS DM Breadoboard.

  8. CANARY phase B: on-sky open-loop tomographic LGS AO results

    NASA Astrophysics Data System (ADS)

    Morris, Tim; Gendron, Eric; Basden, Alastair; Martin, Olivier; Osborn, James; Henry, David; Hubert, Zoltan; Sivo, Gaetano; Gratadour, Damien; Chemla, Fanny; Sevin, Arnaud; Cohen, Matthieu; Younger, Eddy; Vidal, Fabrice; Wilson, Richard; Butterley, Tim; Bitenc, Urban; Reeves, Andrew; Bharmal, Nazim; Raynaud, Henri-François; Kulcsar, Caroline; Conan, Jean-Marc; Huet, Jean-Michel; Perret, Denis; Dickson, Colin; Atkinson, David; Bailie, Tom; Longmore, Andy; Todd, Stephen; Talbot, Gordon; Morris, Simon; Rousset, Gérard; Myers, Richard

    2014-07-01

    CANARY is an on-sky Laser Guide Star (LGS) tomographic AO demonstrator that has been in operation at the 4.2m William Herschel Telescope (WHT) in La Palma since 2010. In 2013, CANARY was upgraded from its initial configuration that used three off-axis Natural Guide Stars (NGS) through the inclusion of four off-axis Rayleigh LGS and associated wavefront sensing system. Here we present the system and analysis of the on-sky results obtained at the WHT between May and September 2014. Finally we present results from the final `Phase C' CANARY system that aims to recreate the tomographic configuration to emulate the expected tomographic AO configuration of both the AOF at the VLT and E-ELT.

  9. World-wide deployment of Robo-AO visible-light robotic laser adaptive optics systems

    NASA Astrophysics Data System (ADS)

    Baranec, Christoph; Riddle, Reed; Law, Nicholas Michael; Lu, Jessica R.; Tonry, John; Tully, R. Brent; Wright, Shelley; Kulkarni, Shrinivas; Severson, Scott; Choi, Philip; Ramaprakash, A.; Chun, Mark; Connelley, Mike; Tokunaga, Alan; Hall, Donald

    2015-08-01

    In the next few years, several modest-sized telescopes around the world will be upgraded with autonomous laser adaptive optics systems based on the Robo-AO prototype deployed at the Palomar Observatory 1.5-m telescope. The prototype commenced scientific operations in June 2012 and more than 19,000 observations have since been performed at the ~0.12" visible-light diffraction limit. We are planning to move the prototype system to the 2.1-m telescope at Kitt Peak for a 3-year deployment which will serve a consortium of users including Caltech, the University of Hawai`i, IUCAA, NCU and institutions in China. Additionally, 2 months per year will be made available to the US astronomical community.New Robo-AO systems are in various stages of development: a clone by IUCAA for the 2-m IGO telescope in India; a natural guide star variant, KAPAO, by Pomona College at the 1-m Table Mountain telescope in California; and second generation Robo-AO systems are planned for the 3-m IRTF and 2.2-m University of Hawai'i telescopes on Maunakea, Hawai`i. The latter will exploit Maunakea's excellent observing conditions to provide higher Strehl ratios, sharper imaging, ~0.07", and correction to lambda = 400 nm. An additional infrared integral-field spectrograph will be fed by the UH 2.2-m Robo-AO system to quickly classify transients, such as supernovae and asteroids, discovered by the ATLAS system in Hawai`i.

  10. Real-time control for the high order, wide field DRAGON AO test bench

    NASA Astrophysics Data System (ADS)

    Basden, Alastair; Bharmal, Nazim A.; Bitenc, Urban; Dipper, Nigel; Morris, Tim; Myers, Richard; Reeves, Andrew; Younger, Eddy

    2014-07-01

    DRAGON is a high order, wide field AO test-bench at Durham. A key feature of DRAGON is the ability to be operated at real-time rates, i.e. frame rates of up to 1kHz, with low latency to maintain AO performance. Here, we will present the real-time control architecture for DRAGON, which includes two deformable mirrors, eight wavefront sensors and thousands of Shack-Hartmann sub-apertures. A novel approach has been taken to allow access to the wavefront sensor pixel stream, reducing latency and peak computational load, and this technique can be implemented for other similar wavefront sensor cameras with no hardware costs. We report on experience with an ELT-suitable wavefront sensor camera. DRAGON will form the basis for investigations into hardware acceleration architectures for AO real-time control, and recent work on GPU and many-core systems (including the Xeon Phi) will be reported. Additionally, the modular structure of DRAGON, its remote control capabilities, distribution of AO telemetry data, and the software concepts and architecture will be reported. Techniques used in DRAGON for pixel processing, slope calculation and wavefront reconstruction will be presented. This will include methods to handle changes in CN2 profile and sodium layer profile, both of which can be modelled in DRAGON. DRAGON software simulation techniques linking hardware-in-the-loop computer models to the DRAGON real-time system and control software will also be discussed. This tool allows testing of the DRAGON system without requiring physical hardware and serves as a test-bed for ELT integration and verification techniques.

  11. Efficient control schemes with limited computation complexity for Tomographic AO systems on VLTs and ELTs

    NASA Astrophysics Data System (ADS)

    Petit, C.; Le Louarn, M.; Fusco, T.; Madec, P.-Y.

    2011-09-01

    Various tomographic control solutions have been proposed during the last decades to ensure efficient or even optimal closed-loop correction to tomographic Adaptive Optics (AO) concepts such as Laser Tomographic AO (LTAO), Multi-Conjugate AO (MCAO). The optimal solution, based on Linear Quadratic Gaussian (LQG) approach, as well as suboptimal but efficient solutions such as Pseudo-Open Loop Control (POLC) require multiple Matrix Vector Multiplications (MVM). Disregarding their respective performance, these efficient control solutions thus exhibit strong increase of on-line complexity and their implementation may become difficult in demanding cases. Among them, two cases are of particular interest. First, the system Real-Time Computer architecture and implementation is derived from past or present solutions and does not support multiple MVM. This is the case of the AO Facility which RTC architecture is derived from the SPARTA platform and inherits its simple MVM architecture, which does not fit with LTAO control solutions for instance. Second, considering future systems such as Extremely Large Telescopes, the number of degrees of freedom is twenty to one hundred times bigger than present systems. In these conditions, tomographic control solutions can hardly be used in their standard form and optimized implementation shall be considered. Single MVM tomographic control solutions represent a potential solution, and straightforward solutions such as Virtual Deformable Mirrors have been already proposed for LTAO but with tuning issues. We investigate in this paper the possibility to derive from tomographic control solutions, such as POLC or LQG, simplified control solutions ensuring simple MVM architecture and that could be thus implemented on nowadays systems or future complex systems. We theoretically derive various solutions and analyze their respective performance on various systems thanks to numerical simulation. We discuss the optimization of their performance and stability issues with respect to classic control solutions. We finally discuss off-line computation and implementation constraints.

  12. Enabling technologies for visible adaptive optics: the Magellan adaptive secondary VisAO camera

    NASA Astrophysics Data System (ADS)

    Kopon, Derek; Males, Jared; Close, Laird M.; Gasho, Victor

    2009-08-01

    Since its beginnings, diffraction-limited ground-based adaptive optics (AO) imaging has been limited to wavelengths in the near IR (?>1?m) and longer. Visible AO (?>1?m) has proven to be difficult because shorter wavelengths require wavefront correction on very short spatial and temporal scales. The pupil must be sampled very finely, which requires dense actuator spacing and fine wavefront sampling with large dynamic range. In addition, atmospheric dispersion is much more significant in the visible than in the near-IR. Imaging over a broad visible band requires a very good Atmospheric Dispersion Corrector (ADC). Even with these technologies, our AO simulations using the CAOS code, combined with the optical and site parameters for the 6.5m Magellan telescope, demonstrate a large temporal variability of visible (?=0.7?m) Strehl on timescales of 50 ms. Over several hundred milliseconds, the visible Strehl can be as high at 50% and as low as 10%. Taking advantage of periods of high Strehl requires either the ability to read out the CCD very fast, thereby introducing significant amounts of read-noise, or the use of a fast asynchronous shutter that can block the low-Strehl light. Our Magellan VisAO camera will use an advanced ADC, a high-speed shutter, and our 585 actuator adaptive secondary to achieve broadband (0.5-1.0 ?m) diffraction limited images on the 6.5m Magellan Clay telescope in Chile at Las Campanas Observatory. These will be the sharpest and deepest visible direct images taken to date with a resolution of 17 mas, a factor of 2.7 better than the diffraction limit of the Hubble Space Telescope.

  13. Comparison of the mass circulation and AO indices as indicators of cold air outbreaks in northern winter

    NASA Astrophysics Data System (ADS)

    Yu, Yueyue; Ren, Rongcai; Cai, Ming

    2015-04-01

    Using the daily ERA-Interim reanalysis data set for the 32 winters in 1979-2011, we find that midlatitude cold air outbreaks (CAOs) tend to preferentially occur within a week after simultaneously stronger mass circulations into the Arctic region in upper levels and out of the Arctic region below. The relationship of CAOs with Arctic Oscillation (AO) is less robust because temporal changes of AO are resulted from a small imbalance between the poleward and equatorward branches of the mass circulation. Results indicate that only when the poleward branch leads the equatorward branch (44% of all cases), CAOs tend to take place within a week after a negative phase of AO, whereas when the equatorward branch leads (19%), CAOs tend to occur after a positive phase of AO. In the remaining cases when the two branches are almost in phase, CAOs can be observed during either negative (24%) or positive (13%) phase of AO.

  14. SCExAO: the most complete instrument to characterize exoplanets and stellar environments

    NASA Astrophysics Data System (ADS)

    Lozi, Julien; Guyon, Olivier; Jovanovic, Nemanja; Singh, Garima; Doughty, Danielle; Pathak, Prashant; Goebel, Sean; Kudo, Tomoyuki

    2015-12-01

    The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument, currently under development for the Subaru Telescope, optimally combines state-of-the-art technologies to directly study exoplanets and stellar environments at the diffraction limit, both in visible and infrared light (0.6 to 2.4 um). The instrument already includes an ultra-fast visible pyramid wavefront sensor operating at 3.5 kHz, a 2k-actuator deformable mirror, a set of optimal coronagraphs that can work as close as 1 l/D, a low-order wavefront sensor, a high-speed speckle control, and two visible interferometric modules, VAMPIRES and FIRST. Stability of the wavefront correction has already been demonstrated on sky, and SCExAO is already producing scientific results. After the integration of the Integral Field Spectrograph (IFS) CHARIS and a Microwave Kinetic Inductance Detector (MKID) in 2016, SCExAO will be one of the most powerful and effective tools for characterizing exoplanets and disks.

  15. The Subaru Coronagraphic Extreme AO High Speed and High Sensitivity Wavefront Sensors

    NASA Astrophysics Data System (ADS)

    Clergeon, Christophe; Guyon, Olivier; Martinache, Frantz; Veran, Jean-Pierre; Gendron, Eric; Rousset, Gérard; Correia, Carlos; Garrel, Vincent

    2013-12-01

    The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system uses advanced coronagraphic technique for high contrast imaging of exoplanets and disks as close as 1 lambda/D from the host star. In addition to unusual optics, achieving high contrast at this small angular separation requires a wavefront sensing and control architecture which is optimized for exquisite control and calibration of low order aberrations. To complement the current near-IR wavefront control system driving a single MEMS type deformable mirror mounted on a tip-tilt mount, two high order and high sensitivity visible wavefront sensors have been integrated to SCEXAO: - a non modulated Pyramid wavefront sensor (CHEOPS) which is a sensitivity improvement over modulated Pyramid systems now used in high performant astronomical AO, - a non linear wavefront sensor designed in 2012 by Subaru Telescope with the collaboration of the NRC-CNRC which is expected to improve significantly the achieved sensitivity of low order aberations measurements. I will present the CHEOPS last results measured downstream the Subaru AO188 system highlighting limits of our instrument and then introduce the primary laboratory images of the first built prototype of the non linear curvature wavefront sensor.

  16. AO/NAO Response to Climate Change. 1; Respective Influences of Stratospheric and Tropospheric Climate Changes

    NASA Technical Reports Server (NTRS)

    Rind, D.; Perlwitz, J.; Lonergan, P.

    2005-01-01

    We utilize the GISS Global Climate Middle Atmosphere Model and 8 different climate change experiments, many of them focused on stratospheric climate forcings, to assess the relative influence of tropospheric and stratospheric climate change on the extratropical circulation indices (Arctic Oscillation, AO; North Atlantic Oscillation, NAO). The experiments are run in two different ways: with variable sea surface temperatures (SSTs) to allow for a full tropospheric climate response, and with specified SSTs to minimize the tropospheric change. The results show that tropospheric warming (cooling) experiments and stratospheric cooling (warming) experiments produce more positive (negative) AO/NAO indices. For the typical magnitudes of tropospheric and stratospheric climate changes, the tropospheric response dominates; results are strongest when the tropospheric and stratospheric influences are producing similar phase changes. Both regions produce their effect primarily by altering wave propagation and angular momentum transports, but planetary wave energy changes accompanying tropospheric climate change are also important. Stratospheric forcing has a larger impact on the NAO than on the AO, and the angular momentum transport changes associated with it peak in the upper troposphere, affecting all wavenumbers. Tropospheric climate changes influence both the A0 and NAO with effects that extend throughout the troposphere. For both forcings there is often vertical consistency in the sign of the momentum transport changes, obscuring the difference between direct and indirect mechanisms for influencing the surface circulation.

  17. Isolation and characterization of an agaro-oligosaccharide (AO)-hydrolyzing bacterium from the gut microflora of Chinese individuals.

    PubMed

    Li, Miaomiao; Li, Guangsheng; Zhu, Liying; Yin, Yeshi; Zhao, Xiaoliang; Xiang, Charlie; Yu, Guangli; Wang, Xin

    2014-01-01

    Agarose (AP) from red algae has a long history as food ingredients in East Asia. Agaro-oligosaccharides (AO) derived from AP have shown potential prebiotic effects. However, the human gut microbes responsible for the degradation of AO and AP have not yet been fully investigated. Here, we reported that AO and AP can be degraded and utilized at various rates by fecal microbiota obtained from different individuals. Bacteroides uniformis L8 isolated from human feces showed a pronounced ability to degrade AO and generate D-galactose as its final end product. PCR-DGGE analysis showed B. uniformis to be common in the fecal samples, but only B. uniformis L8 had the ability to degrade AO. A synergistic strain, here classified as Escherichia coli B2, was also identified because it could utilize the D-galactose as the growth substrate. The cross-feeding interaction between B. uniformis L8 and E. coli B2 led to exhaustion of the AO supply. Bifidobacterium infantis and Bifidobacterium adolescentis can utilize one of the intermediates of AO hydrolysis, agarotriose. Growth curves indicated that AO was the substrate that most favorably sustained the growth of B. uniformis L8. In contrast, ?-carrageenan oligosaccharides (KCO), guluronic acid oligosaccharides (GO), and mannuronic acid oligosaccharides (MO) were found to be unusable to B. uniformis L8. Current results indicate that B. uniformis L8 is a special degrader of AO in the gut microbiota. Because B. uniformis can mitigate high-fat-diet-induced metabolic disorders, further study is required to determine the potential applications of AO. PMID:24622338

  18. Isolation and Characterization of an Agaro-Oligosaccharide (AO)-Hydrolyzing Bacterium from the Gut Microflora of Chinese Individuals

    PubMed Central

    Li, Miaomiao; Li, Guangsheng; Zhu, Liying; Yin, Yeshi; Zhao, Xiaoliang; Xiang, Charlie; Yu, Guangli; Wang, Xin

    2014-01-01

    Agarose (AP) from red algae has a long history as food ingredients in East Asia. Agaro-oligosaccharides (AO) derived from AP have shown potential prebiotic effects. However, the human gut microbes responsible for the degradation of AO and AP have not yet been fully investigated. Here, we reported that AO and AP can be degraded and utilized at various rates by fecal microbiota obtained from different individuals. Bacteroides uniformis L8 isolated from human feces showed a pronounced ability to degrade AO and generate D-galactose as its final end product. PCR-DGGE analysis showed B. uniformis to be common in the fecal samples, but only B. uniformis L8 had the ability to degrade AO. A synergistic strain, here classified as Escherichia coli B2, was also identified because it could utilize the D-galactose as the growth substrate. The cross-feeding interaction between B. uniformis L8 and E. coli B2 led to exhaustion of the AO supply. Bifidobacterium infantis and Bifidobacterium adolescentis can utilize one of the intermediates of AO hydrolysis, agarotriose. Growth curves indicated that AO was the substrate that most favorably sustained the growth of B. uniformis L8. In contrast, κ-carrageenan oligosaccharides (KCO), guluronic acid oligosaccharides (GO), and mannuronic acid oligosaccharides (MO) were found to be unusable to B. uniformis L8. Current results indicate that B. uniformis L8 is a special degrader of AO in the gut microbiota. Because B. uniformis can mitigate high-fat-diet-induced metabolic disorders, further study is required to determine the potential applications of AO. PMID:24622338

  19. Telescópio de pequeno porte como suporte ao ensino em cidades com intensa poluição luminosa II

    NASA Astrophysics Data System (ADS)

    Pereira, P. C. R.; Santos-Júnior, J. M.; Cruz, W. S.

    2003-08-01

    Para a maioria dos estudantes, sua passagem pelo ensino formal fundamental envolve a transmissão de fatos que devem ser guardados para um exame, a habilidade para lembrar fórmulas e, eventualmente, a repetição de experimentos que devem produzir resultados exigidos pelo professor. O resultado deste modelo de ensino, ao longo dos anos, é conhecido por todos: desconhecimento e descontentamento, por parte dos estudantes, de temas relativos ao papel e aos processos da ciência. Acreditamos que a Astronomia, pelo seu caráter observacional, é uma das áreas do conhecimento que pode contribuir neste cenário. A Fundação Planetário da Cidade do Rio de Janeiro possui um telescópio Meade LX-200 (25cm) que, juntamente com as câmeras CCD ST-7E e ST8E, tem sido utilizado em projetos voltados aos estudantes do ensino médio desde o ano 2000. Tais projetos envolvem a condução de um projeto de pesquisa observacional num nível apropriado, e possibilitam o contato com técnicas e novas tecnologias: computador, software para manipulação de dados e gráficos, programas de tratamento e redução de dados, uso de equipamentos óptico-eletrônicos (telescópio e CCD), bem como o processo de aquisição de conhecimento. Dentro da proposta dos anos anteriores, priorizamos projetos de uma noite, ou seja, procuramos trabalhar com fenômenos que apresentem variabilidade com intervalo de recorrência relativamente curto. Em todos os casos, optamos pela fotometria diferencial, que tem se mostrado bastante eficiente para o céu luminoso como o da cidade do Rio de Janeiro. Neste painel, apresentamos alguns dos projetos desenvolvidos no último ano, com 25 estudantes. Apresentamos os resultados da observação da variável pulsante AI Vel (V = 6,6) e da variável cataclísmica FO Aqr (V = 13,5), e do monitoramento do trânsito da lua de Júpiter, Europa, ocorrido em 30 de abril de 2003. As curvas de luz produzidas para as primeiras estão concordantes com as da literatura, assim como os respectivos períodos encontrados (1h20min e 4h48min). No caso do FO Aqr, ficou evidente, também, a modulação decorrente da rotação da anã branca receptora (21min). O erro estimado é de 0,01 magnitude. Propomos uma maior utilização de telescópios de pequeno porte, como suporte ao ensino (médio e superior) em cidades com poluição luminosa. Escolas e Planetários seriam ambientes propícios para a localização do telescópio. Os critérios adotados na escolha dos objetos e o método observacional empregado são também apresentados.

  20. Relationship among SSW, PJO and AO in an Idealized Stratosphere-Troposphere Coupled Model

    NASA Astrophysics Data System (ADS)

    Yoden, S.; Kohma, M.; Nishizawa, S.

    2009-04-01

    Internal intraseasonal variability in the stratosphere-troposphere coupled system contains multiple time-scale variation from stratospheric sudden warming (SSW) to polar-night jet oscillation (PJO) and Arctic oscillation (AO) in the northern hemisphere winter. Relationship among SSW, PJO and AO is investigated with a 14,000-year dataset originally obtained by Nishizawa and Yoden (2005), who performed numerical time integrations of an idealized stratosphere-troposphere global circulation model with sinusoidal surface topography of zonal wavenumber one under a purely periodic annual forcing. Deviation of the pole temperature at 2.6 hPa from the minimum value for each calendar day is analyzed to identify an SSW event with two threshold temperatures, following the analysis procedure introduced by Naito et al. (2003). Statistics of some characteristic values such as the maximum temperature during each SSW event and length of the event are calculated and their seasonal dependence is clarified. As for PJOs, fundamentally the same analysis method as Kodera and Kuroda (2000) is adopted; an EOF analysis is done for the temperature field averaged in the polar region with multiple levels from the surface to the lower mesosphere, after applying a low-pass filter of 15 days for the deviation from the climatological seasonal march. Contributions of EOF1 and EOF2 are 73.8% and 20.5%, respectively. PJOs are identified in a normalized PC1-PC2 phase space, and their statistics are obtained to identify the seasonal dependence. AOs are also studied by a similar EOF analysis on the area-weighted zonal mean sea-level pressure in the northern hemisphere. One of the novel aspects of the present study is the statistical significance of the analyzed results based on the long enough dataset. Seasonal dependence of the features of SSW, PJO and AO is clearly obtained. Another is the finding of statistically significant relationship among SSW, PJO and AO. Both SSW and PJO events are observed in over 8,000 years out of 14,000 years, and the relationship between SSW and PJO is classified into three groups; (1) an SSW event over 10 days before the maximum of PJO, (2) nearly the same timing of SSW and PJO, and (3) PJO without any precursor of SSW. Downward propagation of signals with time is largely different between the groups. Significant increase of the AO index is also obtained before the occurrence date of SSW events. References: Kodera, K. and Y. Kuroda, 2000: Stratospheric and tropospheric aspects of the Arctic Oscillation. Geophys.Res.Lett., 27, 3349-3352. Naito, Y., M. Taguchi and S. Yoden, 2003: A parameter sweep experiment on the effects of the equatorial QBO on stratospheric sudden warming events. J.Atmos.Sci, 60-11, 1380-1394. Nishizawa, S. and S. Yoden, 2005: Distribution functions of a spurious trend in a finite length data set with natural variability: Statistical considerations and a numerical experiment with a global circulation model. J.Geophys.Res., 110, D12105, doi:10.1029/2004JD005714

  1. Increasing Efficiency at the NTF by Optimizing Model AoA Positioning

    NASA Technical Reports Server (NTRS)

    Crawford, Bradley L.; Spells, Courtney

    2006-01-01

    The National Transonic Facility (NTF) at NASA Langley Research Center (LaRC) is a national resource for aeronautical research and development. The government, military and private industries rely on the capability of this facility for realistic flight data. Reducing the operation costs and keeping the NTF affordable is essential for aeronautics research. The NTF is undertaking an effort to reduce the time between data points during a pitch polar. This reduction is being driven by the operating costs of a cryogenic facility. If the time per data point can be reduced, a substantial cost savings can be realized from a reduction in liquid nitrogen (LN2) consumption. It is known that angle-of-attack (AoA) positioning is the longest lead-time item between points. In January 2005 a test was conducted at the NTF to determine the cause of the long lead-time so that an effort could be made to improve efficiency. The AoA signal at the NTF originates from onboard instrumentation then travels through a number of different systems including the signal conditioner, digital voltmeter, and the data system where the AoA angle is calculated. It is then fed into a closed loop control system that sets the model position. Each process along this path adds to the time per data point affecting the efficiency of the data taking process. Due to the nature of the closed loop feed back AoA control and the signal path, it takes approximately 18 seconds to take one pitch pause point with a typical AoA increment. Options are being investigated to reduce the time delay between points by modifying the signal path. These options include: reduced signal filtering, using analog channels instead of a digital volt meter (DVM), re-routing the signal directly to the AoA control computer and implementing new control algorithms. Each of these has potential to reduce the positioning time and together the savings could be significant. These timesaving efforts are essential but must be weighed against possible loss of data quality. For example, a reduction in filtering can introduce noise into the signal and using analog channels could result in some loss of accuracy. Data quality assessments need to be performed concurrently with timesaving techniques since data quality parameters are essential in maintaining facility integrity. This paper will highlight time saving efforts being undertaken or studied at the NTF. It will outline the instrumentation and computer systems involved in setting of the model pitch attitude then suggest changes to the process and discuss how these system changes would effect the time between data points. It also discusses the issue of data quality and how the potential efficiency changes in the system could affect it. Lastly, it will discuss the possibility of using an open loop control system and give some pros and cons of this method.

  2. Relative importance of the AO, NAO and Aleutian Low in predicting regional climate change

    NASA Astrophysics Data System (ADS)

    Paeth, H.; Rauthe, M.; Hense, A.

    2003-04-01

    In recent years, several observational and climate model studies have drawn a picture of Northern Hemisphere circulation modes which are largely sensitive to the greenhouse forcing with implications for regional climate change. The dominant candidates are the Arctic Oscillation (AO), the North Atlantic Oscillation (NAO) and the Aleutian Low (AL). Here, we consider all these modes equally and try to get insight into their relative importance with respect to temperature and rainfall variability over the Northern Hemisphere. The relative importance of AO, NAO and AL time series is determined by stepwise multiple regression with cross validation at every grid point of the globe. This tool is appropriate to sort the predictors - AO, NAO and AL - by their relative contribution to temperature and rainfall predictability and to evaluate the predictability with respect to an independent control data set. This allows to cut off the number of predictors as soon as the mean square error between the multiple regression model and the control data set is increasing. For better reliability of our results, the procedure is applied many times with 100 permutations. This part is based on the NCEP reanalysis data set. For estimating future temperature and rainfall anomalies, a broad model intercomparison study has been carried out, including most state-of-the-art models of the international modeler community. For each circulation mode superensemble-mean time series under greenhouse-gas (GHG) only and GHG plus sulphate aerosol conditions are determined respectively. Concerning annual-mean temperature, the total explained variance by an optimal number of predictors amounts to 60% over northern Europe, Siberia and North America. At most grid points of the Northern Hemisphere, the AO is the most prominent mode, also in the European-Atlantic sector where the NAO is supposed to be the main player. In the North Pacific sector and in some regions of the low latitudes the AL is dominating. The NAO mainly occupies rank 2 in the surroundings of the North Atlantic, the AO holds the same rank in the North Pacific region. This picture is largely independent of the 100 permutations. In terms of the year-to-year precipitation changes, the impact of the circulation modes is less striking, probably due to the high amount of internal variability. However, large-scale anomalies over northern Europe and the western Mediterranean, induced by the AO, as well as the western United States, induced by the AL, are statistically significant. Inserting the superensemble-mean index values, representative of the late 21st century, in the regression equation with optimal numbers of predictors leads to an estimate of future circulation-induced temperature and rainfall anomalies. This contribution is found to be considerable, amounting to around 25% of the total expected mean change as depicted in the IPCC 2001 report.

  3. Effects of The NAO/ao Fluctuations Upon Precipitation Over Sardinia In The 20th Century.

    NASA Astrophysics Data System (ADS)

    Delitala, A.

    The effects at regional scale of decadal fluctuation of the NAO/AO on the 20th cen- tury precipitation over Sardinia will be analyzed. Decadal variations of precipitation will initially be described, by use of the Standardized Anomaly Index (Katz &Glantz, 1986) based on two indicators: the cumulated precipitation (the classical approach) and the number of rainy days. A clear decreasing trend in the last two deacdes, statis- tically significant at the 1% level, will be highlighted. A short survey of connections with MSLP and 500hPA Geopotential Height fields will be used to give an overview of dependence of Sardinia (regional) precipitation on synoptic-scale and planetary scale features. In the following part, three different paradigms of the NAO/AO will be used: the classical two point obscillation, the PCA analysis of MSLP (Thompson &Wallace, 1998) and the centers of action approach (Machel et al., 1998). The results of the anal- ysis of the effects of NAO/AO (described in the former three ways) on precipitation will enable to discuss how such a teleconnection influences regional precipitation on this part of the Mediterranean. Statistical significance of each result will be provided during the presentation. Katz, R., Glantz, M., 1986. "Anatomy of a Rainfall Index". Mon. Wea. Rev., 114, 764-771. Mächel, M., Kapala, A., Flohn, H., 1998. "Behaviour of the Centers of Action above the Atlantic since 1881. Part I: Characteristics of seasonal and interannual Variability". Int. Jou. of Climatol., 18, 1-22. Thopson, D. W. J., Wallace, J. M., 1998. "The Arctic Oscillation signature in the wintertime geopotential height and temperature fields". Geoph. Res. Let., 25, 1297- 1300.

  4. Preliminary results from the chemistry of micrometeoroid experiment (AO 187-1)

    NASA Technical Reports Server (NTRS)

    Horz, Friedrich; Bernhard, R. P.; See, Thomas H.; Warren, J.; Brownlee, Don E.; Laurance, M.

    1991-01-01

    The purpose of experiment AO 187-1 was to expose high purity substrates of suitable cratering properties to obtain detailed crater statistics that may be converted into projectile masses and fluxes and to chemically characterize as many impactors as possible. The latter information would hopefully reveal distinct classes of natural and man-made particles in low-Earth orbit. It was found that crater that yield residues show that natural and man-made impactors may be differentiated and that diversity exists within each group. 'Chondritic' compositions dominate among natural particles, yet some craters contain unmelted fragments of minerals (Olivine and pyroxene).

  5. B'NAI AO...alive, healthy and growing...a brief history.

    PubMed

    Williamowsky, Ben

    2006-03-01

    A daily minyan was held at 7:00 AM each morning at the recent Alpha Omega International Convention in Hollywood, Florida. That was Chanukah week, when a Torah reading is required. Thanks to a request by Allen Ressler, Torah reader, Rabbi Menachem Levy...who is connected local Chabad Congregation, joined us. As participants in the service crowded the designated prayer room, I was moved to reflect on how B'nai AO came about. At the suggestion of International Editor Dan Uditsky, I will share some facts, and especially my own personal memories. PMID:16865851

  6. Tomographic separation of composite spectra - The components of the O-star spectroscopic binary AO Cassiopeiae

    NASA Technical Reports Server (NTRS)

    Bagnuolo, William G., Jr.; Gies, Douglas R.

    1991-01-01

    The UV photospheric lines of the short-period, double-lined O-star spectroscopic binary AO Cas are analyzed. Archival data from IUE (16 spectra uniformly distributed in orbital phase) were analyzed with a tomography algorithm to produce the separate spectra of the two stars in six spectral regions. The spectral classifications of the primary and secondary, O9.5 III and O8 V, respectively, were estimated through a comparison of UV line ratios with those in spectral standard stars. An intensity ratio of 0.5-0.7 (primary brighter) at 1600 A is compatible with the data.

  7. LDEF (Postflight), AO180 : The Effect of Space Environment Exposure on the Properties of Polymer Mat

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO180 : The Effect of Space Environment Exposure on the Properties of Polymer Matrix Composite Materials, Tray D12 The postflight photograph was taken in the SAEF-II facility prior to removal of experiment trays from the LDEF. The Polymer Matrix Composite Materials experiment appears the same as in the flight photograph. The composite containing the aramid (Kevlar) fibers has changed from a yellow to a light brown color and the cylinderical tubes containing the boron and carbon fiber materials have changed from a light green tint to a brown color. The experiment mounting hardware and fasteners seem to be intact and in very good condition.

  8. Using DARC in a multi-object AO bench and in a dome seeing instrument

    NASA Astrophysics Data System (ADS)

    Sáez, Norman; Basden, Alistair; Guzmán, Dani; Dubost, Nicolás.; Berdja, Amokrane

    2014-07-01

    The Durham adaptive Optics Real Time Controller (DARC)1 is a real-time system for astronomical adaptive optics systems originally developed at Durham University and in use for the CANARY instrument. One of its main strengths is to be a generic and high performance real-time controller running on an off-the-shelf Linux computer. We are using DARC for two different implementations: BEAGLE,2 a Multi-Object AO (MOAO) bench system to experiment with novel tomographic reconstructors and LOTUCE2,3 an in-dome turbulence instrument. We present the software architecture for each application, current benchmarks and lessons learned for current and future DARC developers.

  9. LDEF (Prelaunch), AO187-01 : The Chemistry of Micrometeoroids, Tray A03

    NASA Technical Reports Server (NTRS)

    1984-01-01

    LDEF (Prelaunch), AO187-01 : The Chemistry of Micrometeoroids, Tray A03 The prelaunch photograph shows the two (2) clam shell type canisters in their closed position. The canister shells are made of aluminum sheet material with end caps of diecast aluminum. The baseplate and support structure are fabricated from 6000 series aluminum. Fasteners are non-magnetic stainless steel. The electrical box and the stainless steel tubing located on the baseplate protect the drive system wiring. The experiment contains a timing mechanism that provides the intelligence to open the canisters after the Orbiter has departed the area and any initial outgassing or offgassing has occurred.

  10. Semi-Supervised Learning Techniques in AO Applications: A Novel Approach To Drift Counteraction

    NASA Astrophysics Data System (ADS)

    De Vito, S.; Fattoruso, G.; Pardo, M.; Tortorella, F.; Di Francia, G.

    2011-11-01

    In this work we proposed and tested the use of SSL techniques in the AO domain. The SSL characteristics have been exploited to reduce the need for costly supervised samples and the effects of time dependant drift of state-of-the-art statistical learning approaches. For this purpose, an on-field recorded one year long atmospheric pollution dataset has been used. The semi-supervised approach benefitted from the use of updated unlabeled samples, adapting its knowledge to the slowly changing drift effects. We expect that semi-supervised learning can provide significant advantages to the performance of sensor fusion subsystems in artificial olfaction exhibiting an interesting drift counteraction effect.

  11. Optical Photometry of the flaring gamma-ray blazar AO 0235+164

    NASA Astrophysics Data System (ADS)

    Pursimo, Tapio; Losada, Illa R.; Messa, Matteo; Gafton, Emanuel; Ojha, Roopesh

    2016-03-01

    We report optical photometry of the blazar AO 0235+164 obtained with the 2.56m Nordic Optical Telescope in La Palma to look for any enhanced optical activity associated with a recent flare in the daily averaged gamma-ray flux seen in the public lightcurve of the Fermi/LAT instrument: http://fermi.gsfc.nasa.gov/FTP/glast/data/lat/catalogs/asp/current/lightcurves/0235+164_86400.png Fermi/LAT first reported a detection of gamma-ray activity from this source in Sep, 2008 (ATel#1744) and a short timescale flare in Oct 14, 2008 (ATel#1784).

  12. Optical calibration of capacitive sensors for AO: strategy and preliminary results

    NASA Astrophysics Data System (ADS)

    Briguglio, Runa; Xompero, Marco; Riccardi, Armando; Biasi, Roberto; Andrighettoni, Mario

    2012-07-01

    LBT contactless, voice-coil actuators working point ranges from 10 to 100 μm, with a typical position noise of a few nm. To fully take advantage of such large working range in AO operations, an absolute calibration of their capacitive sensor is requested. We implemented and tested an optical calibration technique that is based on a fast interferometer detection of a differential piston superimposed to a low order mirror mode. This procedure has been tested in dome environment at the Large Binocular Telescope.

  13. Altair at Gemini North: Full Sky Coverage Laser AO Correction at Visible Wavelengths

    NASA Astrophysics Data System (ADS)

    Trujillo, Chadwick; Ball, Jesse; Boccas, Maxime; Cavedoni, Chas; Christou, Julian; Coulson, Dolores; Ebbers, Angelic; Emig, Kimberly; Jorgensen, Inger; Kang, Stacy; Lai, Olivier; Matulonis, Anthony; McDermid, Richard; Miller, Bryan; Neichel, Benoit; Oram, Richard; Rigaut, François; Roth, Kathy; Schneider, Thomas; Stephens, Andy; Trancho, Gelys; Walls, Brian; White, John; Gemini Software Team

    2013-12-01

    We present two recent upgrades to the Gemini North Adaptive Optics(AO) system, Altair. These two upgrades provide 100% sky coverage forlow performance AO suitable for improving the natural seeing byfactors of 2 to 3 from blue visible wavelengths (350 nm) through thenear infrared (2.5 micron wavelengths). The first upgrade, dubbed LGS + P1 "Super Seeing" mode allowscorrection of high order aberrations with an on-axis Laser Guide Star(LGS) while tip/tilt correction is performed with a more distantperipheral wavefront sensor (P1). Most currently operating LGS AOsystems are limited in their sky coverage, primarily due to tip/tiltstar availability. Although P1 provides sub-optimal tip/tiltcorrection due to its distance from the science source, its patrolradius allows operation in LGS + P1 mode anywhere in the sky fromdeclinations of +70 degrees to -30 degrees. This mode was offered forscience use at Gemini North in 2013A. We will present typicalperformance and use from its first semester in science operation,where we expect to improve image quality by a factor 2 to 3 overseeing limited images. The second upgrade is the commissioning of the AO system to correct atvisible wavelengths, which is expected to be completed in late 2013.In this mode, Altair will feed the Gemini Multi-Object Spectrograph(GMOS), which is an optical imager as well as a long-slit, multi-slitand integral field unit spectrograph. We intend to replace thecurrent Altair science dichroic with a sodium notch filter, passingonly the 589nm wavelength light from the LGS to the AO system. Therest of the spectrum from 400 nm to the GMOS red cutoff at 1.1 micronsis intended as science capable light. Tip/tilt correction will beperformed close to the science target with the GMOS on-instrumentwavefront sensor or with P1 as in the P1+LGS mode discussed above. Weexpect an image quality improvement of roughly a factor 2 in this modeover seeing limited observations. Since exposure time to reach a given signal-to-noise ratio scalesroughly as the square of the image quality, these two upgradesrepresent a substantial efficiency improvement which is available tonearly all targets normally observed at Gemini North.

  14. Closed-loop tomographic control on HOMER wide-field AO bench: experimental results and identification issues

    NASA Astrophysics Data System (ADS)

    Parisot, Amelie; Costille, Anne; Petit, Cyril; Fusco, Thierry

    2010-07-01

    Adaptive Optics (AO) has a limited corrected field of view because of the anisoplanatism effect. Wide Field AO (WFAO) concepts, such as Multi-Conjugate AO (MCAO), have been developed to overcome this limitation. These complex WFAO systems raise critical challenges such as tomographic control and calibrations. We present new results obtained in closed-loop configuration with the laboratory bench HOMER which is devoted to implementation and validation of these WFAO concepts in the perspective of future VLT/ELT AO systems. Turbulence is generated with rotating phase screens and multi-directional analysis is performed. Tomographic control relies on Linear Quadratic Gaussian control (LQG). The correction can be applied thanks to two Deformable Mirrors (DM). We also focus on calibration issues and models identification. We investigate in particular identification of relative geometry of the wave front sensors, DM altitude and asterism and its impact on performance.

  15. Lateral fixation of AO type-B2 ankle fractures: the Acutrak plus compression screw technique.

    PubMed

    Lee, Yih-Shiunn; Hsu, Tzu-Liang; Huang, Chien-Rae; Chen, Shih-Hao

    2010-08-01

    The Acutrak plus compression screw (APCS) (Acumed Inc., Beaverton, OR, USA) is an intramedullary implant which can achieve stable fixation with minimum soft tissue dissection. The characteristics of the APCS include fully-threaded length, headless, cannulated, and variable thread pitch. Twenty-three patients with AO type-B2 ankle fractures treated with lateral fixation by an APCS were retrospectively reviewed. Evaluation of postoperative roentgenograms for adequacy of reduction revealed a good reduction in 22 of 23 (95.7%) patients. The average wound incision was 4.1 cm. The operative time was 25.3 minutes. All the ankle fractures showed radiographic evidence of healing within four months. At the final follow-up, the ankle scores of the patients were evaluated for functional outcomes. Good to excellent results were obtained in 21 (91.3%) patients. No patient complained of symptomatic hardware. In conclusion, lateral fixation of AO type-B2 ankle fractures by APCS offers several advantages including stable fixation, a small surgical wound, less dissection of soft tissue, no palpable hardware, and easy application with a short operating time. PMID:20177893

  16. Spiromastixones A-O, antibacterial chlorodepsidones from a deep-sea-derived Spiromastix sp. fungus.

    PubMed

    Niu, Siwen; Liu, Dong; Hu, Xinxin; Proksch, Peter; Shao, Zhongzhe; Lin, Wenhan

    2014-04-25

    Fifteen new depsidone-based analogues named spiromastixones A-O (1-15) were isolated from the fermentation broth of a deep-sea Spiromastix sp. fungus. Their structures were elucidated on the basis of extensive NMR and mass spectroscopic analysis in association with chemical conversion. Spiromastixones A-O are classified into two subtypes based on the orientation of ring C relative to ring A, while the n-propyl substituents on rings A and C are rarely seen in natural products. Most analogues are substituted by various numbers of chlorine atoms. All compounds exhibited significant inhibition against Gram-positive bacteria including Staphylococcus aureus, Bacillus thuringiensis, and Bacillus subtilis with MIC values ranging from 0.125 to 8.0 ?g/mL. In addition, compounds 6-10 displayed potent inhibitory effects against methicillin-resistant bacterial strains of S. aureus (MRSA) and S. epidermidis (MRSE), while 10 also inhibited the growth of the vancomycin-resistant bacteria Enterococcus faecalis and E. faecium (VRE). The structure-activity relationships are discussed. PMID:24571273

  17. The Influence of Dominant Global Climate Phenomena ENSO, NAO, and AO on Climate in Serbia

    NASA Astrophysics Data System (ADS)

    Jovanovic, G.; Reljin, I.; Reljin, B.

    2010-09-01

    The relationship between El Niňo and temperatures in Serbia has been proved. Certain correlation among the average monthly temperatures in Serbia and in Niňo 3,4 region, with three months delay, has been found. The fractal analysis of these temperature series was performed via R/S statistic indicating fractal and multifractal (MF) nature of processes. The calculation of cross-correlation coefficients between NAO index and precipitation, temperature, and pressure data in Serbia has proved considerable NAO influence on Serbia region, especially during winter. The following correlation values were obtained between NAO Index and: pressure 0.60, temperature 0,64, both for Belgrade, while for Niksic negative cross-correlation was obtained for precipitation -0,53. The fractal and multifractal analyses of pressure data series on a number of stations in a wide region from Azores to Iceland and Serbia were done. The obtained results showed that each station in the region has characteristic multifractal spectra of pressure data. The teleconnection with NAO has been also proved by the comparisons of EOF analysis of pressure field in Serbia with the EOF for the north Atlantic domain. The analyses of NAO influence based on daily precipitation data on stations in Serbia and NAO daily index plus AO daily index were prepared, too. These results suggest that AO influence in Serbia is more prominent than the one obtained for NAO.

  18. OCam with CCD220, the Fastest and Most Sensitive Camera to Date for AO Wavefront Sensing

    NASA Astrophysics Data System (ADS)

    Feautrier, Philippe; Gach, Jean-Luc; Balard, Philippe; Guillaume, Christian; Downing, Mark; Hubin, Norbert; Stadler, Eric; Magnard, Yves; Skegg, Michael; Robbins, Mark; Denney, Sandy; Suske, Wolfgang; Jorden, Paul; Wheeler, Patrick; Pool, Peter; Bell, Ray; Burt, David; Davies, Ian; Reyes, Javier; Meyer, Manfred; Baade, Dietrich; Kasper, Markus; Arsenault, Robin; Fusco, Thierry; Diaz Garcia, José Javier

    2011-03-01

    For the first time, subelectron readout noise has been achieved with a camera dedicated to astronomical wavefront-sensing applications. The OCam system demonstrated this performance at a 1300 Hz frame rate and with 240 × 240 pixel frame size. ESO and JRA2 OPTICON jointly funded e2v Technologies to develop a custom CCD for adaptive optics (AO) wavefront-sensing applications. The device, called CCD220, is a compact Peltier-cooled 240 × 240 pixel frame-transfer eight-output back-illuminated sensor using the EMCCD technology. This article demonstrates, for the first time, subelectron readout noise at frame rates from 25 Hz to 1300 Hz and dark current lower than 0.01 e- pixel-1 frame-1. It reports on the quantitative performance characterization of OCam and the CCD220, including readout noise, dark current, multiplication gain, quantum efficiency, and charge transfer efficiency. OCam includes a low-noise preamplifier stage, a digital board to generate the clocks, and a microcontroller. The data acquisition system includes a user-friendly timer file editor to generate any type of clocking scheme. A second version of OCam, called OCam2, has been designed to offer enhanced performance, a completely sealed camera package, and an additional Peltier stage to facilitate operation on a telescope or environmentally challenging applications. New features of OCam2 are presented in this article. This instrumental development will strongly impact the performance of the most advanced AO systems to come.

  19. LDEF (Flight), AO187-01 : The Chemistry of Micrometeoroids, Tray A03

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO187-01 : The Chemistry of Micrometeoroids, Tray A03 EL-1994-00680 LDEF (Flight), AO187-01 : The Chemistry of Micrometeoroids, Tray A03 The flight photograph was taken with the LDEF on the Orbiter's RMS arm prior to berthing the spacecraft in the cargo bay. The canisters are in their open condition (they were expected to open about two (2) weeks after launch and close about eleven (11) months into the mission) with three (3) full panels and 3/4th of the fourth panel covered with a highly reflective gold foil (>99.99 percent pure).The remaining area is covered with strips of other detector materials: zirconium, beryllium, titanium, platium, aluminum, carbon, Kapton, polyethylene and TEFLON®. The exposed fasteners are non-magnetic stainless steel. All of the exposed materials seem to be secure and no damage is evident. The contamination stain that has changed the white paint dot on the tray clamp blocks to brown also coats the tray flanges and the aluminum canister hardware. The end support beam scuff plate in the photograph was a bright yellow prior to launch but is a much darker, mustard yellow after the space exposure.

  20. LDEF (Postflight), AO187-01 : The Chemistry of Micrometeoroids, Tray A03

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO187-01 : The Chemistry of Micrometeoroids, Tray A03 EL-1994-00266 LDEF (Postflight), AO187-01 : The Chemistry of Micrometeoroids, Tray A03 The experiment is shown in the postflight configuration before closing the canisters with ground support equipment that bypassed the experiments onboard electronics circuitry. Three full panels and approximately 3/4th of the other panel are covered with gold foil (>99.99 percent pure). The remaining area on the fourth panel is covered with strips of other detector materials: zirconium, beryllium, titanium, platium, aluminum, carbon, Kapton, polyethylene and TEFLON®. A brown stain is visible on the experiment tray flanges, however, most of the stains observed in the flight photograph are obscured by reflected light. All materials remain intact with no visual evidence of damage to the experiment. The reflection of a video camera on a tripod and light sources can be seen on the gold foil covered panels. The experiment canisters are shown after being closed by using the experiments ground support equipment. The stain buildup can be clearly seen at the vertical center of the right tray flange. The clean area was located under the experiment tray clamp block and was not exposed to the staining medium. The stain also coats other areas that were exposed during the mission but are not as noticeable. The experiment hardware seems to be intact and have no damage.

  1. Instrument control software development process for the multi-star AO system ARGOS

    NASA Astrophysics Data System (ADS)

    Kulas, M.; Barl, L.; Borelli, J. L.; Gässler, W.; Rabien, S.

    2012-09-01

    The ARGOS project (Advanced Rayleigh guided Ground layer adaptive Optics System) will upgrade the Large Binocular Telescope (LBT) with an AO System consisting of six Rayleigh laser guide stars. This adaptive optics system integrates several control loops and many different components like lasers, calibration swing arms and slope computers that are dispersed throughout the telescope. The purpose of the instrument control software (ICS) is running this AO system and providing convenient client interfaces to the instruments and the control loops. The challenges for the ARGOS ICS are the development of a distributed and safety-critical software system with no defects in a short time, the creation of huge and complex software programs with a maintainable code base, the delivery of software components with the desired functionality and the support of geographically distributed project partners. To tackle these difficult tasks, the ARGOS software engineers reuse existing software like the novel middleware from LINC-NIRVANA, an instrument for the LBT, provide many tests at different functional levels like unit tests and regression tests, agree about code and architecture style and deliver software incrementally while closely collaborating with the project partners. Many ARGOS ICS components are already successfully in use in the laboratories for testing ARGOS control loops.

  2. Correlation effects on the different crystal structures of AO2 (A=Na, K, and Ba)

    NASA Astrophysics Data System (ADS)

    Kim, Minjae; Kang, Chang-Jong; Min, B. I.

    2013-03-01

    In alkali superoxide (A=Na, and K), the structural phase transition from high symmetry to low symmetry structures occurs upon cooling. On the other hand, in BaO2 peroxide, the crystal structure is always the high symmetry tetragonal structure of KO2, independent of temperature. To resolve these different crystal structures of AO2 (A=Na, K, and Ba), we have calculated phonon dispersions of AO2, assuming the high symmetry tetragonal structure of KO2 with first-principle band structure method in the generalized gradient approximation (GGA) incorporating the Coulomb interaction U (GGA+U). From softened phonon modes, we have shown that, in KO2 and NaO2, the degeneracy of the incomplete pi anti-bonding level is lifted with the symmetry lowering such as Jahn-Teller effect with help of Coulomb correlation U. In contrast, in BaO2, the pi anti-bonding level of the peroxide is completely filled without degeneracy. Thus, U is not effective on the phonon structure so that the structural instability does not occur in BaO2.

  3. LDEF (Prelaunch), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09

    NASA Technical Reports Server (NTRS)

    1983-01-01

    LDEF (Prelaunch), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 EL-1994-00302 LDEF (Prelaunch), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 The prelaunch photograph was taken in SAEF II at KSC prior to installation of the Cascade Variable Conductance Heat Pipe Experiment (CVCHPE) on the LDEF. The Cascade Variable Conductance Heat Pipe Experiment (CVCHPE) occupies a 6 inch deep LDEF peripheral experiment tray and consist of two series connected variable conductance heatpipes, a black chrome solar collector panel and a silvered TEFLON® radiator panel, a power source to support six thermistor-type temperature monitoring sensors and actuations of two valves. Fiberglass standoffs and internal insulation blankets thermally isolated the experiment from the experiment tray and the LDEF interior. The outside of the CVCHPE, except the collector and radiator panels, was covered with an aluminumized Kapton multilayer insulation (MLI) blanket with an outer layer of 0.076 mm thick Kapton. The two patches of thin film materials, part of Experiment S1001 by NASA GSFC, were attached to the cover of the external thermal blanket with Kapton tape. The experiment was assembled and mounted in the experiment tray with non-magnetic stainless steel fasteners.

  4. LDEF (Prelaunch), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09

    NASA Technical Reports Server (NTRS)

    1983-01-01

    LDEF (Prelaunch), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 EL-1994-00302 LDEF (Prelaunch), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 The prelaunch photograph was taken in SAEF II at KSC prior to installation of the Cascade Variable Conductance Heat Pipe Experiment (CVCHPE) on the LDEF. The Cascade Variable Conductance Heat Pipe Experiment (CVCHPE) occupies a 6 inch deep LDEF peripheral experiment tray and consist of two series connected variable conductance heatpipes, a black chrome solar collector panel and a silvered TEFLON® radiator panel, a power source to support six thermistor-type temperature monitoring sensors and actuations of two valves. Fiberglass standoffs and internal insulation blankets thermally isolated the experiment from the experiment tray and the LDEF interior. The outside of the CVCHPE, except the collector and radiator panels, was covered with an aluminumized Kapton multilayer insulation (MLI) blanket with an outer layer of 0.076 mm thick Kapton. The two patches of thin film materials, part of Experiment S1001 by NASA GSFC, were attached to the cover of the external thermal blanket with Kapton tape. The experiment was assembled and mounted in the experiment tray with non-magnetic stainless steel fasteners.

  5. Risk factors associated with Campylobacter jejuni infections in Curaçao, Netherlands Antilles.

    PubMed

    Endtz, Hubert P; van West, Hanneke; Godschalk, Peggy C R; de Haan, Lidewij; Halabi, Yaskara; van den Braak, Nicole; Kesztyüs, Barbara I; Leyde, Ewald; Ott, Alewijn; Verkooyen, Roel; Price, Lawrence J; Woodward, David L; Rodgers, Frank G; Ang, C Wim; van Koningsveld, Rinske; van Belkum, Alex; Gerstenbluth, Izzy

    2003-12-01

    A steady increase in the incidence of Guillain-Barré syndrome (GBS) with a seasonal preponderance, almost exclusively related to Campylobacter jejuni, and a rise in the incidence of laboratory-confirmed Campylobacter enteritis have been reported from Curaçao, Netherlands Antilles. We therefore investigated possible risk factors associated with diarrhea due to epidemic C. jejuni. Typing by pulsed-field gel electrophoresis identified four epidemic clones which accounted for almost 60% of the infections. One hundred six cases were included in a case-control study. Infections with epidemic clones were more frequently observed in specific districts in Willemstad, the capital of Curaçao. One of these clones caused infections during the rainy season only and was associated with the presence of a deep well around the house. Two out of three GBS-related C. jejuni isolates belonged to an epidemic clone. The observations presented point toward water as a possible source of Campylobacter infections. PMID:14662945

  6. Robotic Laser Adaptive Optics Imaging of 715 Kepler Exoplanet Candidates Using Robo-AO

    NASA Astrophysics Data System (ADS)

    Law, Nicholas M.; Morton, Tim; Baranec, Christoph; Riddle, Reed; Ravichandran, Ganesh; Ziegler, Carl; Johnson, John Asher; Tendulkar, Shriharsh P.; Bui, Khanh; Burse, Mahesh P.; Das, H. K.; Dekany, Richard G.; Kulkarni, Shrinivas; Punnadi, Sujit; Ramaprakash, A. N.

    2014-08-01

    The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging to search for blended nearby stars, which may be physically associated companions and/or responsible for transit false positives. In this paper, we present the results from the 2012 observing season, searching for stars close to 715 Kepler planet candidate hosts. We find 53 companions, 43 of which are new discoveries. We detail the Robo-AO survey data reduction methods including a method of using the large ensemble of target observations as mutual point-spread-function references, along with a new automated companion-detection algorithm designed for large adaptive optics surveys. Our survey is sensitive to objects from ?0.''15 to 2.''5 separation, with magnitude differences up to ?m ? 6. We measure an overall nearby-star probability for Kepler planet candidates of 7.4% ± 1.0%, and calculate the effects of each detected nearby star on the Kepler-measured planetary radius. We discuss several Kepler Objects of Interest (KOIs) of particular interest, including KOI-191 and KOI-1151, which are both multi-planet systems with detected stellar companions whose unusual planetary system architecture might be best explained if they are "coincident multiple" systems, with several transiting planets shared between the two stars. Finally, we find 98% confidence evidence that short-period giant planets are two to three times more likely than longer-period planets to be found in wide stellar binaries.

  7. Using the vector vortex coronagraph in the ExAO regime at Palomar: lessons learned

    NASA Astrophysics Data System (ADS)

    Mawet, D.; Serabyn, E.; Burruss, R.

    2010-10-01

    We have been using the vector vortex coronagraph intensively on sky behind the 1.5-meter well-corrected subaperture on the 5-m Hale telescope at the Palomar observatory. This configuration allowed us to experiment the use of this small inner working angle, high throughput, clear and symmetric off-axis discovery space coronagraph in the ExAO regime. We will discuss the system level issues we had to tackle to make the most of this instrumental setup: low-frequency and high frequency pointing stabilization, focus removal, non-common path wavefront errors calibrations using the modified Gerchberg-Saxton phase retrieval technique, synchronized observing strategy. Without the availability of differential imaging capabilities such as angular or spectral differential imaging, we had to rely on the well-proven reference star subtraction. While not ideal, this method will be the only way to get to close separations since both ADI and SDI fail at very small angles. Fast and reproducible AO target acquisition allowed us to implement an efficient target-reference nodding method which is the key to achieving a high degree of correlation in the quasi-static speckle pattern required by smart data processing methods such as the locally optimized combination of images (LOCI).

  8. A decadal survey of AO wavefront sensing detector developments in Europe

    NASA Astrophysics Data System (ADS)

    Feautrier, Philippe

    2011-09-01

    The success of the next generation of instruments for 8 to 40-m class telescopes will depend on the ability of Adaptive Optics (AO) systems to provide excellent image quality and stability. This will be achieved by increasing the sampling, wavelength range and correction quality of the wave front error in both spatial and time domains. The modern generation of AO wavefront sensor detectors started in the late nineties with the development of the CCD50 detector by e2v under ESO contract for the ESO NAOS AO system. With a 128x128 pixels format, this 8 outputs CCD runs at a 500 Hz frame rate with a readout noise of 7e-. A major breakthrough has been achieved with the recent development of the CCD220, also by e2v technologies. This 240x240 pixels 8 outputs EMCCD (CCD with internal multiplication), also developed by e2v, has been jointly funded by ESO and Europe under the FP6 programme. The CCD220 detector and the OCAM2 camera are now the most sensitive system in the world for advanced adaptive optics systems, offering an astonishing <0.2 e readout noise at a frame rate of 1500 Hz with negligible dark current. Extremely easy to operate, OCAM2 only needs a 24 V power supply and a modest water cooling circuit. This system is extensively described elsewhere in this conference (see Gach J-L. et al). An upgrade of OCAM2 is foreseen to boost its frame rate to 2500 Hz, opening the window of XAO wavefront sensing for the ELT. Since this major success, new developments started in Europe. One is fully dedicated to Laser Guide Star AO for the ELT. The spot elongation from a LGS SH wavefront sensor induces an increase of the pixel format. Two detectors are currently developed by e2v. The NGSD will be a 672x672 pixels CMOS detector with a readout noise of 4e (goal 1e) at 700 Hz frame rate. The LGSD is a scaling of the NGSD with 1680x1680 pixels and 3 e readout noise (goal 1e) at 700 Hz frame rate. New technologies will be developed for that purpose: new CMOS pixel architecture, CMOS back thinned and back illuminated device, full digital outputs. In addition, the CMOS technology is extremely robust in a telescope environment. Both detectors will be used on the ELT, depending on the AO system considered. Additional developments also started for wavefront sensing in the infrared based on new breakthrough in Avalanche Photodiode (APD) arrays. A 256x256 array is currently developed by ESO and Selex while a similar development started in France with the RAPID project. The latter should offer a 320x240 8 outputs 30 microns IR array, sensitive from 0.4 to 3.2 microns, with 2 e readout noise at 1500 Hz frame rate.

  9. Volcanic Activity of Io Monitored with Keck-10m AO in 2003-2004

    NASA Astrophysics Data System (ADS)

    Marchis, F.; Davies, A. G.; Gibbard, S. G.; Le Mignant, D.; Lopes, R. M.; Macintosh, B.; de Pater, I.

    2004-12-01

    With the demise of the Galileo mission, the monitoring of Io volcanic activity lies in the hands of ground-based observers. Our group regularly observed Io with the Keck-10m Adaptive Optics (AO) system and its NIRC-2 camera at 1-5 microns wavelength range. The angular resolution achieved is 0.05" in Kc band (2.2 microns), i.e. 120-140 km on Io at opposition. Approximately 5 to 8 active volcanic centers are usually detected on one 3 or 5 microns AO image with a T between 500 and 1000 K. On rare occasions, we detected the thermal output at shorter wavelength (1-2.5 micron) indicating a colour temperature >1300 K. For instance, our data revealed the presence on Jan. 26, 2003, of a bright eruption close to Janus Patera (5±3S, 39±3W) with intensity in Lp band (3.8 micron) of 11±1 GW/sr/micron and ˜2 GW/sr/micron in Kc band (2.2 micron). Another bright eruption close to Tupan Patera (16±4S, 137±4W) was seen on Mar. 8, 2003 (UT) with a I(Lp)=18 ±1 GW/sr/micron and I(Kc) ˜3 GW/sr/micron. More recently, data taken on May 28 and 30, 2004, show the thermal emission of an eruptive center (called 0405A) located at 17±2 S, 6±1W (close to Ilmarinera Patera which has never been seen active) with a I(Kc) ˜7 GW/sr/micron and I(Lp)=166±6 GW/sr/micron. This energetic eruption was also detected in H band (1.6 micron) with I(H) ˜3 GW/sr/micron. Because we obtained the brightness of these eruptions in at least three different wavelengths, we can perform a more precise analysis of their activity using a basaltic cooling lava flow model (Davies, 1996). In the case of 0405A, we can conclude that we are observing an episode of fire-fountaining (a young, hot event) whose total output is estimated to ˜9E12 W (i.e. 10% of Io average total output), more energetic than Tvashtar 2001. The source of these active centers and their activity will be compared with previous Galileo NIMS/SSI observations. We will conclude describing how the future use of AO technique will help to monitor and understand this extraterrestrial and exotic volcanism.

  10. l-Fucose Stimulates Utilization of d-Ribose by Escherichia coli MG1655 ?fucAO and E. coli Nissle 1917 ?fucAO Mutants in the Mouse Intestine and in M9 Minimal Medium?

    PubMed Central

    Autieri, Steven M.; Lins, Jeremy J.; Leatham, Mary P.; Laux, David C.; Conway, Tyrrell; Cohen, Paul S.

    2007-01-01

    Escherichia coli MG1655 uses several sugars for growth in the mouse intestine. To determine the roles of l-fucose and d-ribose, an E. coli MG1655 ?fucAO mutant and an E. coli MG1655 ?rbsK mutant were fed separately to mice along with wild-type E. coli MG1655. The E. coli MG1655 ?fucAO mutant colonized the intestine at a level 2 orders of magnitude lower than that of the wild type, but the E. coli MG1655 ?rbsK mutant and the wild type colonized at nearly identical levels. Surprisingly, an E. coli MG1655 ?fucAO ?rbsK mutant was eliminated from the intestine by either wild-type E. coli MG1655 or E. coli MG1655 ?fucAO, suggesting that the ?fucAO mutant switches to ribose in vivo. Indeed, in vitro growth experiments showed that l-fucose stimulated utilization of d-ribose by the E. coli MG1655 ?fucAO mutant but not by an E. coli MG1655 ?fucK mutant. Since the ?fucK mutant cannot convert l-fuculose to l-fuculose-1-phosphate, whereas the ?fucAO mutant accumulates l-fuculose-1-phosphate, the data suggest that l-fuculose-1-phosphate stimulates growth on ribose both in the intestine and in vitro. An E. coli Nissle 1917 ?fucAO mutant, derived from a human probiotic commensal strain, acted in a manner identical to that of E. coli MG1655 ?fucAO in vivo and in vitro. Furthermore, l-fucose at a concentration too low to support growth stimulated the utilization of ribose by the wild-type E. coli strains in vitro. Collectively, the data suggest that l-fuculose-1-phosphate plays a role in the regulation of ribose usage as a carbon source by E. coli MG1655 and E. coli Nissle 1917 in the mouse intestine. PMID:17709419

  11. The MeJA-inducible copper amine oxidase AtAO1 is expressed in xylem tissue and guard cells.

    PubMed

    Ghuge, Sandip A; Carucci, Andrea; Rodrigues-Pousada, Renato A; Tisi, Alessandra; Franchi, Stefano; Tavladoraki, Paraskevi; Angelini, Riccardo; Cona, Alessandra

    2015-01-01

    Copper amine oxidases oxidize the polyamine putrescine to 4-aminobutanal with the production of the plant signal molecule hydrogen peroxide (H2O2) and ammonia. The Arabidopsis (Arabidopsis thaliana) gene At4g14940 (AtAO1, previously referred to as ATAO1) encodes an apoplastic copper amine oxidase expressed in lateral root cap cells and developing xylem, especially in root protoxylem and metaxylem precursors. In our recent study, we demonstrated that AtAO1 expression is strongly induced in the root vascular tissues by the wound-signal hormone methyl jasmonate (MeJA). Furthermore, we also demonstrated that the H2O2 derived by the AtAO1-driven oxidation of putrescine, mediates the MeJA-induced early protoxylem differentiation in Arabidopsis roots. H2O2 may contribute to protoxylem differentiation by signaling developmental cell death and by acting as co-substrate in peroxidase-mediated cell wall stiffening and lignin polymerization. Here, by the means of AtAO1 promoter::green fluorescent protein-?-glucuronidase (AtAO1::GFP-GUS) fusion analysis, we show that a strong AtAO1 gene expression occurs also in guard cells of leaves and flowers. The high expression levels of AtAO1 in tissues or cell types regulating water supply and water loss may suggest a role of the encoded protein in water balance homeostasis, by modulating coordinated adjustments in anatomical and functional features of xylem tissue and guard cells during acclimation to adverse environmental conditions. PMID:26241131

  12. LDEF (Flight), AO187-01 : The Chemistry of Micrometeoroids, Tray A11

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO187-01 : The Chemistry of Micrometeoroids, Tray A11 The Chemistry of Micrometeoroid Experiment (CME) flight photograph was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay and shows six (6) aluminum detector plates mounted in a three(3) inch deep LDEF peripheral experiment tray. The plates are unprotected and are exposed to the total mission environment, ground handling as well as flight. Non-magnetic stainless steel fasteners are used to attach the plates in the LDEF provided experiment tray. The experiment appears to be in good shape with all hardware intact. Impact craters, that appear as small white imperfections in the dark blue background, can be seen on all six (6) detector plates. The apparent dark blue color of the aluminum detector panels in this photograph is the result of the lighting, reflections on the panels and the camera angle.

  13. LDEF (Postflight), AO187-02 : Chemical and Isotropic Measurements of Micrometeoroids by Secondary Io

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO187-02 : Chemical and Isotropic Measurements of Micrometeoroids by Secondary Ion Mass Spectrometry, Tray E08 This postflight photograph shows an experiment that has been severely degraded due to orbital exposure on the leading edge of the LDEF. The metallic coated thin Mylar film has been lost on each of the capture cells. As the thin Mylar film failed, the material curled tightly into small conical shapes and can be seen still attached to the aluminum mounting structure edges of many capture cells. Close examination of capture cells near the tray center clearly show the four individual high purity germanium plates with some of the bonding material exposed between plates. The green tint on the germanium plate at the right edge of the experiment tray is a reflection from the lights in the high bay area of SAEF II at KFC. Dim reflections from various sources can be seen on other sections of the experiment.

  14. Optical observations of the outburst of blazar AO 0235+16

    NASA Astrophysics Data System (ADS)

    Balonek, T. J.; Lam, M. T.

    2008-09-01

    Observations at the Colgate University Foggy Bottom Observatory confirm the spectacular nature of the current optical outburst in the blazar AO 0235+16 reported by Villata et al (ATEL #1724). The blazar has reached a brightness level, R ~ 14.1, comparable to outbursts in 1990-91, 1992, 1998, and 2007. Preliminary reductions of CCD images indicate the blazar was at R ~ 16.2 on September 4.2 (UT), R ~ 15.4 on September 20.2 - observations hindered by the close proximity of the Moon, R ~ 15.0 on September 21.2, R ~ 14.2 on September 23.2, and R ~ 14.1 on September 24.2.

  15. ShaneAO: wide science spectrum adaptive optics system for the Lick Observatory

    NASA Astrophysics Data System (ADS)

    Gavel, Donald; Kupke, Renate; Dillon, Daren; Norton, Andrew; Ratliff, Chris; Cabak, Jerry; Phillips, Andrew; Rockosi, Connie; McGurk, Rosalie; Srinath, Srikar; Peck, Michael; Deich, William; Lanclos, Kyle; Gates, John; Saylor, Michael; Ward, Jim; Pfister, Terry

    2014-07-01

    A new high-order adaptive optics system is now being commissioned at the Lick Observatory Shane 3-meter telescope in California. This system uses a high return efficiency sodium beacon and a combination of low and high-order deformable mirrors to achieve diffraction-limited imaging over a wide spectrum of infrared science wavelengths covering 0.8 to 2.2 microns. We present the design performance goals and the first on-sky test results. We discuss several innovations that make this system a pathfinder for next generation AO systems. These include a unique woofer-tweeter control that provides full dynamic range correction from tip/tilt to 16 cycles, variable pupil sampling wavefront sensor, new enhanced silver coatings developed at UC Observatories that improve science and LGS throughput, and tight mechanical rigidity that enables a multi-hour diffraction-limited exposure in LGS mode for faint object spectroscopy science.

  16. LDEF (Flight), AO180 : The Effect of Space Environment Exposure on the Properties of Polymer Matrix

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO180 : The Effect of Space Environment Exposure on the Properties of Polymer Matrix Composite Materials, Tray D12 The flight photograph was taken from the Orbiter aft flight deck during the LDEF retrieval. During the mission, the tray surface was at an angle of approximately ninety-eight (98) degrees to the orbital velocity vector and therefore exposed to a lower atomic oxygen flux than if parallel with the velocity vector. A very light stain is present on white paint dots on experiment tray clamps along the lower edge of the tray. The Polymer Matrix Composite Materials experiment has several changes to material colors. The composite containing the aramid (Kevlar) fibers has changed from a yellow to a light brown color and the cylindrical tubes containing the boron and carbon fiber materials have changed from a light green tint to a brown color.

  17. The variability and periods in the BL Lac AO 0235+164

    NASA Astrophysics Data System (ADS)

    Fan, J. H.; Kurtanidze, O.; Liu, X.; Liu, Y.; Wang, H. T.; Yuan, Y. H.; Hao, J. M.; Wu, D. X.; Cai, W.; Xiao, H. B.; Pei, Z. Y.

    2015-03-01

    Variability is one of the extreme observational properties of BL Lacertae objects. AO 0235+164 is a well studied BL Lac through the whole electro-magnetic wavebands, it is violently variable in the optical bands. In the present work, we show its optical R band photometric observations carried out during the period of Nov. 2006 to Dec. 2012 using the Ap6E CCD camera attached to the primary focus of the 70 cm meniscus telescope at Abastumani Observatory, Georgia. It shows a large variation of ?R = 4.88 mag (14.20 - 19.08 mag) during our monitoring period. When periodicity analysis methods are adopted to its R observations from our Abastumani monitoring programme and those in the literature, the signs of some periods, P 1 = 8.26 yr, P 2 = 0.55 yr, P 3 = 0.85 yr, P 4 = 1.99 yr are found.

  18. LDEF (Postflight), AO139A : Growth of Crystals From Solutions in Low Gravity, Tray G06

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO139A : Growth of Crystals From Solutions in Low Gravity, Tray G06 The postflight photograph was taken in the SAEF II at KSC after the experiment tray was removed from the LDEF. The experiment tray flanges have become discolored with a light tan stain except where the tray clamp blocks were located. A darker stain appears to exist at the intersection of the white cover plate and the upper left flange of the experiment tray. The Crystal Growth experiment appears to have survived the extended mission with no visible damage. The experiment cover plate, originally white, appears to be discolored by a very light brown stain but is intact and securely in place.

  19. LDEF (Postflight), AO015 : Free-Flyer Biostack Experiment, Tray G02

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO015 : Free-Flyer Biostack Experiment, Tray G02 The post flight photograph was taken in the SAEF II at KSC after the experiment tray was removed from the LDEF. The experiment tray flanges and sidewalls have become discolored with a light tan stain except where the tray clamp blocks were located. The Biostack experiment appears to have survived the extended mission with no visible damage. The experiment housings are intact and all hardware is securely in place. The detector housings appear to be discolored with a stain similar to that on the tray hardware. The exposed Kapton H foil covering windows in two (2) detector housings do not appear to have sustained damage dur ing the extended mission. The perforated dome on two (2) of the detector housings has a slight tan discoloration but no indication of damage.

  20. Subaru Strategic Exploration of Exoplanets and Disks with HiCIAO/AO188 (SEEDS)

    NASA Astrophysics Data System (ADS)

    Tamura, Motohide

    2009-08-01

    Since the first detection of exoplanets orbiting normal stars in 1995, many exciting discoveries have been made, but our understanding of planetary systems and their formation is far from complete. A census of companions to stars over a wide range of ages will provide important clues to the formation and evolution of stars, brown dwarfs, and planets. Armed with a much better performance than that of the previous coronagraphic imager with adaptive optics (CIAO and AO36 combination), we will conduct a Subaru+High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO)+AO188 imaging survey, searching for giant planets (1 Mj

  1. A History of Correlations Between Optical and Radio Outbursts in the Blazar AO 0235+164

    NASA Astrophysics Data System (ADS)

    McGrath, E. J.; Balonek, T. J.; Brandt, T. J.

    2000-05-01

    We present a ten year optical light curve for the blazar AO 0235+164 from 1989 through mid-1999. Observations were conducted at the Foggy Bottom Observatory at Colgate University using a sixteen inch Cassegrain telescope and CCD camera. Herein we note the correlations between optical and radio variations (radio observations obtained at the University of Michigan Radio Astronomy Observatory, UMRAO). MacLeod, Andrew, and Harvey (1976); Ledden, Aller, and Dent (1976); and Rieke et al. (1976) first noted a correlation between the optical and radio variations in a 1975 outburst of AO 0235+164. Balonek and Dent (1980) showed a second correlation in a 1979 outburst. Subsequent optical outbursts and further optical-radio correlations have been studied by several authors. We study the long and short time scale variations in four additional optical outbursts in 1990, 1991, 1992, and 1998. We find that some of the bursts appear to be strongly correlated with radio bursts, while others do not exhibit simple correlations. Different physical phenomena may be needed in order to explain the differences in these outbursts. In the correlated cases, the optical burst appears to either nearly coincide with a radio burst, or precede a subsequent radio burst by a few months. The time scales of the outbursts agree with the generally accepted model of Blandford and Konigl (1979) of a relativistic shock propagating down a jet. In addition, intra-night variability is seen during these outbursts on much shorter time scales and is most likely caused by another phenomenon.

  2. Robotic laser adaptive optics imaging of 715 Kepler exoplanet candidates using Robo-AO

    SciTech Connect

    Law, Nicholas M.; Ziegler, Carl; Morton, Tim; Riddle, Reed; Tendulkar, Shriharsh P.; Bui, Khanh; Dekany, Richard G.; Kulkarni, Shrinivas; Punnadi, Sujit; Baranec, Christoph; Ravichandran, Ganesh; Johnson, John Asher; Burse, Mahesh P.; Das, H. K.; Ramaprakash, A. N.

    2014-08-10

    The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging to search for blended nearby stars, which may be physically associated companions and/or responsible for transit false positives. In this paper, we present the results from the 2012 observing season, searching for stars close to 715 Kepler planet candidate hosts. We find 53 companions, 43 of which are new discoveries. We detail the Robo-AO survey data reduction methods including a method of using the large ensemble of target observations as mutual point-spread-function references, along with a new automated companion-detection algorithm designed for large adaptive optics surveys. Our survey is sensitive to objects from ≈0.''15 to 2.''5 separation, with magnitude differences up to Δm ≈ 6. We measure an overall nearby-star probability for Kepler planet candidates of 7.4% ± 1.0%, and calculate the effects of each detected nearby star on the Kepler-measured planetary radius. We discuss several Kepler Objects of Interest (KOIs) of particular interest, including KOI-191 and KOI-1151, which are both multi-planet systems with detected stellar companions whose unusual planetary system architecture might be best explained if they are 'coincident multiple' systems, with several transiting planets shared between the two stars. Finally, we find 98% confidence evidence that short-period giant planets are two to three times more likely than longer-period planets to be found in wide stellar binaries.

  3. User perceptions on coastal resource state and management options in Curaçao.

    PubMed

    Debrot, A O; Nagelkerken, I

    2000-12-01

    Public environmental awareness and support for management measures are key determinants of the scope for successful implementation of natural resource management. To assess user perceptions and opinions on resource state and potential management options for the coastal zone of Curaçao, we queried 250 coastal resource users from around the island (sport divers, part-time artisanal fishermen and recreational boaters) using questionnaires. There is wide awareness of a long-term decline in coastal resource condition as measured by various indicators. Even among fishermen there was wide awareness of anthropogenic contributors to the decline, broad agreement of management measures required and a general willingness to contribute to management by means of annual license fees. Some of the more salient findings include the endorsement by fishermen of the current ban on spearfishing (81%), the regulation of the beach seine fishery for scad (77%), the introduction of fish reserves (72%), special protection for sea turtles (90%), conch (82%), and lobsters (72%), and notable support for gradual elimination of trap fisheries (45%). Also, both divers (65%) and boaters (92%) expressed the importance to them of an attractive coastline, with both groups expressing preference for natural (un-built) coastline (>74%) above other categories. Management based on the concept "user pays", as already implemented in the Netherlands Antilles on Saba and Bonaire, is well supported by the resource user public. A review of other main constraints such as finances and institutional capacity, shows that conditions are quite favorable for implementation of new legislation. Modem coral reef management is urgently needed in Curaçao to safeguard a key natural resource and concerted action is called for on the part of government agencies, legislators and elected officials. PMID:15266797

  4. Aspergillus oryzae AoSO is a novel component of stress granules upon heat stress in filamentous fungi.

    PubMed

    Huang, Hsiang-Ting; Maruyama, Jun-ichi; Kitamoto, Katsuhiko

    2013-01-01

    Stress granules are a type of cytoplasmic messenger ribonucleoprotein (mRNP) granule formed in response to the inhibition of translation initiation, which typically occurs when cells are exposed to stress. Stress granules are conserved in eukaryotes; however, in filamentous fungi, including Aspergillus oryzae, stress granules have not yet been defined. For this reason, here we investigated the formation and localization of stress granules in A. oryzae cells exposed to various stresses using an EGFP fusion protein of AoPab1, a homolog of Saccharomyces cerevisiae Pab1p, as a stress granule marker. Localization analysis showed that AoPab1 was evenly distributed throughout the cytoplasm under normal growth conditions, and accumulated as cytoplasmic foci mainly at the hyphal tip in response to stress. AoSO, a homolog of Neurospora crassa SO, which is necessary for hyphal fusion, colocalized with stress granules in cells exposed to heat stress. The formation of cytoplasmic foci of AoSO was blocked by treatment with cycloheximide, a known inhibitor of stress granule formation. Deletion of the Aoso gene had effects on the formation and localization of stress granules in response to heat stress. Our results suggest that AoSO is a novel component of stress granules specific to filamentous fungi. The authors would specially like to thank Hiroyuki Nakano and Kei Saeki for generously providing experimental and insightful opinions. PMID:23991062

  5. GOALS, STRATEGIES AND FIRST DISCOVERIES OF AO327, THE ARECIBO ALL-SKY 327 MHz DRIFT PULSAR SURVEY

    SciTech Connect

    Deneva, J. S.; Stovall, K.; Martinez, J. G.; Jenet, F.; McLaughlin, M. A.; Bates, S. D.; Bagchi, M.; Freire, P. C. C.

    2013-09-20

    We report initial results from AO327, a drift survey for pulsars with the Arecibo telescope at 327 MHz. The first phase of AO327 will cover the sky at declinations of –1° to 28°, excluding the region within 5° of the Galactic plane, where high scattering and dispersion make low-frequency surveys sub-optimal. We record data from a 57 MHz bandwidth with 1024 channels and 125 μs sampling time. The 60 s transit time through the AO327 beam means that the survey is sensitive to very tight relativistic binaries even with no acceleration searches. To date we have detected 44 known pulsars with periods ranging from 3 ms to 2.21 s and discovered 24 new pulsars. The new discoveries include 3 ms pulsars, three objects with periods of a few tens of milliseconds typical of young as well as mildly recycled pulsars, a nuller, and a rotating radio transient. Five of the new discoveries are in binary systems. The second phase of AO327 will cover the sky at declinations of 28°-38°. We compare the sensitivity and search volume of AO327 to the Green Bank North Celestial Cap survey and the GBT350 drift survey, both of which operate at 350 MHz.

  6. A roadmap for a new era turbulence studies program applied to the ground-based astronomy supported by AO

    NASA Astrophysics Data System (ADS)

    Masciadri, Elena; Rousset, Gérard; Fusco, Thierry; Basden, Alastair; Bonifacio, Piercarlo; Fuensalida, Jesus; Robert, Clélia; Sarazin, Marc; Wilson, Richard; Ziad, Aziz

    2013-12-01

    Sites selection for ELTSs concluded and a new era opens for turbulence studies in application to the ground-based astronomy supported by AO. If in the last decade the main interest of astronomy has been focused on the characterization of sites, now priorities change. In the last years more and more AO systems have seen their first light. A few more complex AO techniques are still in a phase of verification/validation. The efficiency of the operating and forthcoming AO systems can strongly be affected by turbulence and observation strategies rely on our ability in knowing in advance the turbulence spatial distribution in a region around the telescope. Progresses in development of more sophisticated AO techniques (such as the LTAO, MCAO and MOAO) definitely depend on a more detailed knowledge of the main turbulence features such as the turbulence stratification at high vertical resolution. An European working group has been recently set-up aiming at defining the roadmap of a program of site testing campaigns for OT measurements having multiple goals mainly addressed to support requirements for 3D OT modeling with hydrodynamical approach and AO at wide field in application to the ground-based astronomy. The main first objective of this program will be the absolute instrument cross-calibration (in particular the vertical profilers for the whole troposphere and low stratosphere ~20km) and validation of techniques for turbulence stratification on the same vertical range at high vertical resolution (with the optimal goal of 100-200m). In this contribution we will present the motivations of our work, the goals, the instrumentation we are taking into accounts, the different strategies and constraints we are considering for the conception of site testing campaigns.

  7. Comparative analysis of the main bioactive components of San-ao decoction and its series of formulations.

    PubMed

    Shu, Xiaoyun; Tang, Yuping; Jiang, Chenxue; Shang, Erxing; Fan, Xinshen; Ding, Anwei

    2012-01-01

    A high performance liquid chromatographic (HPLC) method with diode array detection (DAD) was established for simultaneous determination of seven main bioactive components in San-ao decoction and its series of formulae (San-ao decoction, Wu-ao decoction, Qi-ao decoction and Jia-wei San-ao decoction). Seven compounds were analyzed simultaneously with a XTerra C(18) column (4.6 mm × 250 mm, 5 µm) using a linear gradient elution of a mobile phase containing acetonitrile (A) and a buffer solution (0.02 mol/L potassium dihydrogen phosphate and adjusted to pH 3 using phosphoric acid) (B); the flow rate was 1.0 mL/min. The sample was detected with DAD at 210, 254 and 360 nm and the column was maintained at 30 °C. All the compounds showed good linearity (r2 > 0.9984) in the tested concentration range. The precisions were evaluated by intra-day and inter-day tests, and relative standard deviation (R.S.D.) values within the range of 0.83%–2.53% and 0.64%–2.77% were reported, respectively. The recoveries of the quantified compounds were observed to cover a range from 95.34% and 104.82% with R.S.D. values less than 2.72%. The validated method was successfully applied for the simultaneous determination of seven main bioactive components including ephedrine (1), amygdalin (2), liquiritin (3), benzoic acid (4), isoliquiritin (5), formononetin (6) and glycyrrhizic acid (7) in San-ao decoction and its series of formulae. The results also showed a wide variation in the content of the identified active compounds in these samples, which could also be helpful to illustrate the drug interactions after some herbs combined in different formulations. PMID:23117432

  8. Bioremediation of bisphenol-A polluted soil by Sphingomonas bisphenolicum AO1 and the microbial community existing in the soil.

    PubMed

    Matsumura, Yoshinobu; Akahira-Moriya, Ayako; Sasaki-Mori, Miho

    2015-01-01

    Bisphenol A (BPA, 2,2'-Bis (4-hydroxyphenyl) propane) is an artificial pollutant that is easily detected in soil and water environments. BPA decomposition and removal from the environment is relatively difficult due to its stability. This study evaluated the BPA decomposition and removal activities of the microbial community existing in the soil with or without Sphingomonas bisphenolicum AO1, and revealed the toxic effects of BPA towards the microbial community. The microbial community in soil was able to degrade BPA at 1.0 mg·g(-1) soil or lower, although its degradation was slow. On the other hand, BPA at more than 10 mg·g(-1) soil was not only degraded by the microbial community but also decreased its diversity, suggesting that BPA is harmful to many microorganisms. PCR-TTGE analysis and the cloned 16S rRNA gene sequence analysis indicated that Sphingomonadales, Xanthomonadales, Burkholderiales and Pseudomonadales in the microbial community might independently or cooperatively degrade BPA. On the other hand, supplementation with strain AO1 was able to significantly improve the BPA decomposition activity of the microbial community in soil even at 10 mg BPA·g(-1) soil, although BPA at 100 mg·g(-1) soil overwhelmed the BPA decomposition activity of strain AO1. Furthermore, it was also concluded that strain AO1 could not inhabit BPA purified soil after decomposition of BPA by strain AO1 and the soil microbial community, suggesting that the application of strain AO1 could be a low-burden method for the decomposition and removal of BPA from the natural environment. PMID:25817811

  9. GeMS: from the on-sky experimental system to science operation. The AO point of view

    NASA Astrophysics Data System (ADS)

    Vidal, Fabrice; Neichel, Benoit; Rigaut, François; Carrasco, Rodrigo; Winge, Claudia; Pessev, Peter; Serio, Andrew; Arriagada, Gustavo; Moreno, Cristian; Rambold, William; Luhrs, Javier; Boccas, Maxime; D'Orgeville, Celine; Fesquet, Vincent; Trujillo, Chadwick; Galvez, Ramon; Gausachs, Gaston; Vucina, Tomislav; Montes, Vanessa; Urrutia, Cristian; Marchant, Claudio; Diggs, Sarah

    2013-12-01

    Two years after its first light in 2011, GeMS, the Gemini Multi conjugate adaptive optics System achieved the science verification process and started queue observations. From the Adaptive Optics (AO) point of view it is time to summarize the performance provided by the system after more than 6 months of science on very different observing conditions. We present a statistical study of the overall performance from the AO data recorded by the GeMS telemetry. In particular we study the seeing and LGS photon return performance dependency and conclude on the current limitations of the system

  10. The Early Cretaceous evolution of SE China: Insights from the Changle-Nan'ao Metamorphic Belt

    NASA Astrophysics Data System (ADS)

    Li, Ye; Ma, Chang-Qian; Xing, Guang-Fu; Zhou, Han-Wen

    2015-08-01

    The Mesozoic geology in SE China is characterized by widespread Jurassic-Cretaceous magmatism. There appears, however, an episode of "magmatic quiescence" at ca. 130-110 Ma in terms of increasing high-precision isotopic age data. The causes and regional tectonic significance of this magmatic quiescence are unclear. In this paper, we report integrated in situ U-Pb, Hf and O isotope analyses of zircons from four mica schist samples along Changle-Nan'ao Metamorphic Belt in SE China coast, and use these data to discuss the provenances of these metasedimentary rocks, the timing of the regional metamorphism and their implications for the regional tectonic evolution. The majority of zircons from the mica schists are euhedral to anhedral crystals showing clear concentric zoning under cathodoluminescence (CL) images. Metamorphic zircon rims with bright luminescence are overgrown on the some of the euhedral to anhedral zoned zircons. The zoned zircons from all mica schist samples are homogeneous in U-Pb age zircon ages (between 131 and 148 Ma, peaking at 141 Ma), O isotopes (?18O = 5.6 ± 0.8‰, 2SD, n = 106), and, to the less extent, Hf isotopes (?Hf(T) = - 4.7 to - 1.4 for the Dongshan mica schists, and - 1.4 to 2.2 for the Putian mica schists). They are most likely detrital zircons sourced from the regional Early Cretaceous felsic volcanic rocks (the Nanyuan Formation) and/or coeval intrusions in Fujian Province. The sedimentary protoliths of these mica schists were likely deposited in fore-arc basins. The metamorphic zircon overgrowths have relatively low Th/U ratios; they are dated at ~ 130-100 Ma, with two peaks at ~ 125 Ma and ~ 108 Ma. The first metamorphic age of ~ 125 Ma is coincident with the timing of regional Early Cretaceous magmatic quiescence, while the second metamorphic age of ~ 108 Ma is consistent with the timing of reinitiation of regional Cretaceous magmatism. We use a model of collision between the West Philippines and SE China blocks to interpret our new results. According to this model, the intensive Early Cretaceous (ca. 140-130 Ma) magmatism along the coastal region of SE China was attributed to the subduction of the Paleo-Pacific plate beneath SE China. Collision between the West Philippines and SE China blocks at ~ 130-120 Ma resulted in the regional "magmatic quiescence" and formation of the Changle-Nan'ao Metamorphic Belt. Post-collisional extension triggered the reinitiation of magmatism associated with amphibolite-facies metamorphism at ~ 110 Ma.

  11. Interannual variations of the blocking high over the Ural Mountains and its association with the AO/NAO in boreal winter

    NASA Astrophysics Data System (ADS)

    Li, Chao; Zhang, Qingyun; Ji, Liren; Peng, Jingbei

    2012-04-01

    This paper analyzes interannual variations of the blocking high over the Ural Mountains in the boreal winter and their association with the Arctic Oscillation/North Atlantic Oscillation (AO/NAO). In January, the relationship between the Ural blocking high (UR) and the AO index is statistically significant. The UR tends to occur more frequently and with greater strength during negative AO periods. Some strong URs also occur during positive AO phases (positive UR-AO events), as in January 2008. This paper discusses the characteristics of atmospheric circulation in the cases of positive UR-AO events and contrast cases (negative UR-AO events). The eastward extending of the Icelandic Low (IL) center and the associated NAO dipole anomaly pattern in the upstream region may play a more important role for the UR-AO events. When the center of the IL shifts eastward to 30°W, the amplitude of zonal wavenumber 2 (wavenumber 3) is intensified in the positive (negative) UR-AO events, which favors positive (negative) height anomalies over the Urals. Further analyses indicate that the intensified zonal wind in high latitudes and weakened zonal wind in midlatitudes over the North Atlantic Ocean render the eastward shift of the IL and the NAO dipole anomaly pattern. The Ural blocking in January 2008 bears similar characteristics to the positive UR-AO events.

  12. [The AO external clamp fixator. New techniques in external stabilization of tibial fractures].

    PubMed

    Haas, N P; Schütz, M; Frigg, R; Südkamp, N P; Hoffmann, R

    1994-11-01

    A serious disadvantage of conventional external fixators is the opening of the medullary canal. This creates a direct communication between the canal and the exterior. The new pinless external fixator does not have this disadvantage. The clamps of the new fixator system do not penetrate cortical bone, they simply rest on the cortical surface. The clinical indications of this easily managed system are fractures of the tibial shaft in cases in which primary internal fixation is precluded either by precarious local or general conditions, or even by a lack of infrastructure. In such situations the pinless external fixator is an excellent device to achieve a good fracture stabilisation rapidly, while leaving open all subsequent alteration of treatment. In case of secondary change to an intramedullary nail the pinless fixator facilitates the procedure, because this fixator can be also used as an distractor during nailing. Furthermore this fixator can be combined with any intramedullary nail to increase the stability in case of very proximal or distal as well as highly instable shaft fractures. The clamps of the pinless external fixator set are used in combination with the standard AO fixator system. PMID:7821065

  13. LDEF (Prelaunch), AO139A : Growth of Crystals From Solutions in Low Gravity, Tray G06

    NASA Technical Reports Server (NTRS)

    1984-01-01

    LDEF (Prelaunch), AO139A : Growth of Crystals From Solutions in Low Gravity, Tray G06 The prelaunch photograph was taken in the SAEF II at KSC prior to installation of the integrated experiment tray on the LDEF. The Growth of Crystals From Solution in Low Gravity experiment consist of four specially designed reactors housed in a thermally controlled aluminum cylinder, heaters, a data recording and control system and lithium / sulfur dioxide batteries as the power source. The experiment was thermally isolated from the earth albedo by an aluminum cover plate attached to clips installed on the experiment tray sidewalls. The cover plate outward facing surface was coated with Chemglaze A276 white paint over a Chemglaze 9924 wash primer; the aluminum surface facing the tray interior remained uncoated. The experiment was assembled in a twelve (12) inch deep LDEF experiment tray, the cover plate installed and the tray released for mounting on the earth facing end of the LDEF. The experiment was assembled with non-magnetic stainless steel fasten ers.

  14. Characterization, expression profile, and promoter analysis of the Rhodeus uyekii vitellogenin Ao1 gene.

    PubMed

    Kong, Hee Jeong; Kim, Ju Lan; Moon, Ji Young; Kim, Woo-Jin; Kim, Hyung Soo; Park, Jung Youn; Cho, Hyun Kook; An, Cheul Min

    2014-01-01

    The fish Vitellogenin (Vg) gene has been applied as a biomarker for exposure to estrogenic compounds in the aquatic environment. In this study, we cloned and characterized Vg cDNA from the Korean rose bitterling Rhodeus uyekii (Ru-Vg). The Ru-Vg cDNA encodes a 1424-amino-acid polypeptide that belongs to the VgAo1 family and contains a putative signal peptide, lipovitellin I, phosvitin, and lipovitellin II, but does not contain the vWFD domain or the C-terminal peptide. The deduced Ru-Vg protein has high amino acid identity (73.97%-32.17%) with fish Vg proteins. Pairwise alignment and phylogenetic analysis revealed that Ru-Vg is most closely related to Acheilognathus yamatsutae Vg. Ru-Vg transcripts were detected using quantitative polymerase chain reaction in all tissues tested, with the highest level of expression observed in the ovary. Ru-Vg mRNA was upregulated in R. uyekii hepatopancreas cells in response to treatment with 17β-estradiol (E2) or 17α-ethinylestradiol (EE2). Luciferase reporter expression, driven by the 5'-regulatory region of the Ru-Vg gene spanning from -1020 bp to the start codon was induced by the estrogen receptor and was synergistically activated by treatment with E2 or EE2. These results suggest that R. uyekii and the Ru-Vg gene may be useful as biomarkers for exposure to E2 or EE2. PMID:25329620

  15. Factors contributing to inconsistent condom use among heterosexual men in Curaçao.

    PubMed

    Stutterheim, Sarah E; Bertens, Madelief G B C; Mevissen, Fraukje E F; Schaalma, Herman P

    2013-01-01

    This study explored, from a public health perspective, factors that contribute to inconsistent condom use by men in Curaçao through semi-structured face-to-face interviews with 21 heterosexual men. The findings show that there is an important disconnect between what is considered culturally appropriate sexual behaviour for men and women and condom use, that diverging from prescribed notions of masculinity and femininity in order to use condoms consistently is difficult, and that condom use is particularly problematic in the context of concurrent partnerships and sexual economic exchanges. Participants further reported that Caribbean family structures, whereby mothers assume the role as primary caregiver and fathers contribute biologically but, to a much lesser extent socially, also have an impact on condom use. Additionally, consistent condom use was reported to be impeded by a cultural taboo on talking seriously about sex and sexual health. In their totality, findings provide important input from men for the development of sexual health promotion interventions that are cognizant of the cultural context in which inconsistent condom use occurs, and that are geared not only to the individual level but also to the interpersonal and structural levels. PMID:23350609

  16. The L3Vision CCD220 with its OCam test camera for AO applications in Europe

    NASA Astrophysics Data System (ADS)

    Feautrier, Philippe; Gach, Jean-Luc; Balard, Philippe; Guillaume, Christian; Downing, Mark; Stadler, Eric; Magnard, Yves; Denney, Sandy; Suske, Wolfgang; Jorden, Paul; Wheeler, Patrick; Skegg, Michael; Pool, Peter; Bell, Ray; Burt, David; Reyes, Javier; Meyer, Manfred; Hubin, Norbert; Baade, Dietrich; Kasper, Markus; Arsenault, Robin; Fusco, Thierry; Diaz Garcia, Jose Javier

    2008-07-01

    ESO and JRA2 OPTICON have jointly funded e2v technologies to develop a custom CCD for Adaptive Optic Wave Front Sensor (AO WFS) applications. The device, called CCD220, is a compact Peltier-cooled 240×240 pixel frametransfer 8-output back-illuminated sensor. Using the electron-multiplying technology of L3Vision detectors, the device is designed to achieve sub-electron read noise at frame rates from 25 Hz to 1,500 Hz and dark current lower than 0.01 e-/pixel/frame. The development has many unique features. To obtain high frame rates, multiple EMCCD gain registers and metal buttressing of row clock lines are used. The baseline device is built in standard silicon. In addition, two speculative variants have been built; deep depletion silicon devices to improve red response and devices with an electronic shutter to extend use to Rayleigh and Pulsed Laser Guide Star applications. These are all firsts for L3Vision CCDs. These CCD220 detectors have now been fabricated by e2v technologies. This paper describes the design of the device, technology trade-offs, and progress to date. A Test Camera, called "OCam", has been specially designed and built for these sensors. Main features of the OCam camera are extensively described in this paper, together with first light images obtained with the CCD220.

  17. Pt-TiO2/graphene photocatalysts for degradation of AO7 dye under visible light

    NASA Astrophysics Data System (ADS)

    Hsieh, S. H.; Chen, W. J.; Wu, C. T.

    2015-06-01

    In this work, the hydrothermal method was used for synthesizing Pt-TiO2/graphene nanocomposites. Obtained Pt-TiO2/graphene photocatalysts were characterized by Raman spectroscopy, X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, photoluminescence spectroscopy, and UV-vis spectroscopy. The photocatalytic activity of the Pt-TiO2/graphene nanocomposite catalyst was assessed by examining the degradation of acid orange 7 (AO7) dye from aqueous solutions as a probe reaction under solar light irradiations. X-ray photoelectron spectroscopy analyses showed that the Pt ions substituted in the TiO2 lattice were present mainly in the Pt(II) state. Pt-TiO2/graphene exhibited higher photocatalytic activities than TiO2/graphene under visible light irradiation. The visible light activity of Pt-TiO2/graphene was strongly affected by the calcination temperature and the amounts of H2PtCl6, which were optimal at 500 °C and 10% H2PtCl6, respectively. The degradation efficiency of the Pt-TiO2/graphene nanocomposite was 99% after 6 h of visible light irradiation. The enhanced photodegradation activity might be mainly attributed to the role of Pt-TiO2 as a charge generating center and graphene played as electron acceptor and transporter in the nanocomposite, which effectively suppressed the charge recombination and promoted the charge transfer within the composite.

  18. Characterization, Expression Profile, and Promoter Analysis of the Rhodeus uyekii Vitellogenin Ao1 Gene

    PubMed Central

    Kong, Hee Jeong; Kim, Ju Lan; Moon, Ji Young; Kim, Woo-Jin; Kim, Hyung Soo; Park, Jung Youn; Cho, Hyun Kook; An, Cheul Min

    2014-01-01

    The fish Vitellogenin (Vg) gene has been applied as a biomarker for exposure to estrogenic compounds in the aquatic environment. In this study, we cloned and characterized Vg cDNA from the Korean rose bitterling Rhodeus uyekii (Ru-Vg). The Ru-Vg cDNA encodes a 1424-amino-acid polypeptide that belongs to the VgAo1 family and contains a putative signal peptide, lipovitellin I, phosvitin, and lipovitellin II, but does not contain the vWFD domain or the C-terminal peptide. The deduced Ru-Vg protein has high amino acid identity (73.97%–32.17%) with fish Vg proteins. Pairwise alignment and phylogenetic analysis revealed that Ru-Vg is most closely related to Acheilognathus yamatsutae Vg. Ru-Vg transcripts were detected using quantitative polymerase chain reaction in all tissues tested, with the highest level of expression observed in the ovary. Ru-Vg mRNA was upregulated in R. uyekii hepatopancreas cells in response to treatment with 17?-estradiol (E2) or 17?-ethinylestradiol (EE2). Luciferase reporter expression, driven by the 5'-regulatory region of the Ru-Vg gene spanning from ?1020 bp to the start codon was induced by the estrogen receptor and was synergistically activated by treatment with E2 or EE2. These results suggest that R. uyekii and the Ru-Vg gene may be useful as biomarkers for exposure to E2 or EE2. PMID:25329620

  19. LDEF (Prelaunch), AO015 : Free-Flyer Biostack Experiment, Tray G02

    NASA Technical Reports Server (NTRS)

    1984-01-01

    LDEF (Prelaunch), AO015 : Free-Flyer Biostack Experiment, Tray G02 The prelaunch photograph shows the Bio stack experiment containers mounted on a baseplate and installed in a six (6) inch deep LDEF end corner experiment tray. Non-magnetic stainless steel fasteners were used in all mechanical joint assemblies. The Biostack experiment consist of twenty (20) detector units in hermetically sealed aluminum housings mounted on aluminum baseplates. Eight (8) detector units are mounted on a baseplate and installed in a six (6) inch peripheral tray adjacent to the LDEF trailing edge and twelve (12) detector units mounted on a baseplate are located in the tray shown and will be installed on the earth facing end of the LDEF. The experiment housings and the mounting plate have a thin chro mic anodize surface coating to meet thermal requirements. Two (2) housings have windows cov ered with Kapton H foil that provides a light filter with low radiation absorption. Two (2) additional housings have windows covered with Kapton H foil but also have perforated aluminum domes to limit incoming earth albedo.

  20. The Robo-AO KOI Survey: Laser Adaptive Optics Imaging of Every Kepler Exoplanet Candidate

    NASA Astrophysics Data System (ADS)

    Ziegler, Carl; Law, Nicholas M.; Baranec, Christoph; Morton, Tim; Riddle, Reed L.

    2016-01-01

    The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star (KOI) with laser adaptive optics imaging to hunt for blended nearby stars which may be physically associated companions. With the unparalleled efficiency provided by the first fully robotic adaptive optics system, we perform the critical search for nearby stars (0.15" to 4.0" separation with contrasts up to 6 magnitudes) that pollute the observed planetary transit signal, contributing to inaccurate planetary characteristics or astrophysical false positives. We present approximately 3300 high resolution observations of Kepler planetary hosts from 2012-2015, with ~500 observed nearby stars. We measure an overall nearby star probability rate of 16.2±0.8%. With this large dataset, we are uniquely able to explore broad correlations between multiple star systems and the properties of the planets which they host. We then use these clues for insight into the formation and evolution of these exotic systems. Several KOIs of particular interest will be discussed, including possible quadruple star systems hosting planets and updated properties for possible rocky planets orbiting in the habitable zone.

  1. Integration of SAXO, the VLT-SPHERE extreme AO : final performance

    NASA Astrophysics Data System (ADS)

    Fusco, Thierry; Sauvage, Jean-François; Petit, Cyril; Costille, Anne; Dohlen, Kjetil; Beuzit, Jean-Luc; Mouillet, David; Puget, Pascal; Gluck, Laurence; Rochat, Sylvain; Baruffolo, Andrea; Salasnich, Bernardo; Kasper, Markus; Suarez, Marcos; Soenke, Christian; Fedrigo, Enrico; Baudoz, Pierre; Sevin, Arnaud; Perret, Denis; Wildi, François

    2013-12-01

    The direct imaging of exoplanet is an up to date instrumental challenge, as well as a scientific exciting goal. Contrary to indirect methods, the study of exoplanet's own light witnesses for biomarkers presence in their atmosphere. Observing such a faint object close to its bright host star requires dedicated instrumental observation from the ground. SPHERE and GPI are two of these instruments, currently on final AIT phase, for a very first light during this year. Both instruments developed during the last 5 years are composed of extremely high performance AO system (XAO) able to compensate for the optical deformation caused by the turbulence of earth atmosphere. Moreover, the final performance of such a system is limited by the static light residuals present in the imaging focal plane, caused by uncorrected static optical aberrations. The direct imaging of exoplanet therefore also requires to perform self-calibration in order to attenuate these residual and enhance the coronagraphic extinction. This paper presents the final ongoing AIT results of the SPHERE instrument, and mainly focuses on XAO aspects. An exhaustive view of last SAXO performance in lab is shown. In particular, such improvement as the Optimised Modal Gain, optimized Kalman filtering of vibration, and Garbage collection are the key point to reach the final performance. The behavior of the instrument with realistic turbulence strength, wind speed, flux conditions are studied. The self-calibration module, based on phase diversity measurement of NCPA, demonstrates the ultimate performance of the instrument, in term of flux extinction and future scientific results.

  2. Lycibarbarspermidines A-O, New Dicaffeoylspermidine Derivatives from Wolfberry, with Activities against Alzheimer's Disease and Oxidation.

    PubMed

    Zhou, Zheng-Qun; Fan, Hong-Xia; He, Rong-Rong; Xiao, Jia; Tsoi, Bun; Lan, Kang-Hua; Kurihara, Hiroshi; So, Kwok-Fai; Yao, Xin-Sheng; Gao, Hao

    2016-03-23

    Fifteen new dicaffeoylspermidine derivatives, lycibarbarspermidines A-O (1-15), were isolated from the fruit of Lycium barbarum (wolfberry). The structures were unambiguously determined by spectroscopic analyses and chemical methods. Dicaffeoylspermidine derivatives, a rare kind of plant secondary metabolites, are primarily distributed in the family of Solanaceae. Only six compounds were structurally identified, and all of them are acyclic aglycones. Compounds 1-15 are the first glycosidic products of dicaffeoylspermidine derivatives, and compounds 14-15 are the first cyclization products of dicaffeoylspermidine derivatives. Moreover, dicaffeoylspermidine derivatives were first isolated and identified from wolfberry. The short-term memory assay on a transgenic fly Alzheimer's disease (AD) model showed that 1-15 exhibited different levels of anti-AD activity. The oxygen radical absorbance capacity assay revealed that 1-15 all displayed antioxidant capacity. Both anti-AD and antioxidant functions are related to the effects of wolfberry. Therefore, dicaffeoylspermidine derivatives are considered beneficial constituents responsible for the antiaging, neuroprotective, anti-AD, and antioxidant effects of wolfberry. PMID:26953624

  3. Reproducibility of the AO/ASIF and Gartland classifications for supracondylar fractures of the humerus in children?

    PubMed Central

    Rocha, Igor Tadeu Silveira; Faria, André de Siqueira; Filho, Carlos Fontoura; Rocha, Murilo Antônio

    2015-01-01

    Objective To evaluate the reproducibility of the radiographic classifications of Gartland and the Association for Osteosynthesis/Association for the Study of Internal Fixation (AO/ASIF) for supracondylar fractures of the humerus in children. Methods On two occasions, 50 radiographs in anteroposterior and lateral views were evaluated by three pediatric orthopedists in accordance with the Gartland and AO/ASIF pediatric classifications. Their responses were subjected to statistical analysis consisting of calculation of the ? coefficient to assess the intra- and interobserver concordance, in both classifications. Results The strength of the intraobserver concordance was high or near perfect for the three examiners in the two classification systems. The strength of the interobserver concordance was high in the two systems, with ? coefficients of 0.756 for the Gartland classification and 0.766 for the AO/ASIF classification. Conclusion The Gartland and AO/ASIF classification systems showed similar reproducibility and performance. High strength of concordance was seen in the intra- and interobserver analyses. PMID:26229928

  4. Tighter multipole-based integral estimates and parallel implementation of linear-scaling AO-MP2 theory.

    PubMed

    Doser, Bernd; Lambrecht, Daniel S; Ochsenfeld, Christian

    2008-06-21

    Within an atomic-orbital-based (AO-based) formulation of second-order Møller-Plesset perturbation theory (MP2), we present a novel screening procedure which allows us to preselect numerically significant two-electron integrals more efficiently, especially for large basis sets. The screening is based on our recently introduced multipole-based integral estimates (MBIE) method [J. Chem. Phys., 2005, 123, 184102], that allows to exploit the 1/R(4) or 1/R(6) coupling between electronic charge distributions in transformed integral products within AO-MP2. In this way, linear scaling is attained with fully-controlled numerical accuracy. Furthermore, a parallel implementation of our linear-scaling AO-MP2 method is described, which also allows us to perform calculations with larger basis sets. First calculations reveal that for e.g. linear alkanes the scaling of the number of required transformed integral products is almost equal for 6-31G* and cc-pVTZ basis sets. Using the improved MBIE screening, the largest parallel calculation was performed for a ribozyme fragment consisting of 497 atoms and 5697 basis functions, while our largest AO-MP2 calculation was performed for a stacked DNA system (16 base pairs) comprising 1052 atoms and 10 674 basis functions on a single processor. PMID:18535715

  5. Ionic Polymer-Coated Laccase with High Activity and Enhanced Stability: Application in the Decolourisation of Water Containing AO7

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaolin; Hua, Ming; Lv, Lu; Pan, Bingcai

    2015-02-01

    Eliminating dyes in environmental water purification remains a formidable challenge. Laccase is a unique, environmentally friendly and efficient biocatalyst that can degrade pollutants. However, the use of laccase for the degradation of pollutants is considerably limited by its susceptibility to environmental changes and its poor reusability. We fabricated a novel biocatalyst (LacPG) by coating polyethylenimine onto the native laccase (Lac) followed by crosslinking with glutaraldehyde. The stability of the resulting LacPG was highly enhanced against pH variations, thermal treatments and provided better long-term storage with a negligible loss in enzymatic activity. Compared to Lac, LacPG exhibited significantly higher decolourisation efficiency in the degradation of a representative azo dye, acid orange 7 (AO7), which resulted from the electrostatic attraction between the coating and AO7. LacPG was separated from the AO7 solution using an ultrafiltration unit. The increased size and modified surface chemistry of LacPG facilitated ultrafiltration and reduced membrane fouling. LacPG exhibited enhanced stability, high catalytic activity and favourable properties for membrane separation; therefore, LacPG could be continuously reused in an enzymatic membrane reactor with a high efficiency for decolourising water containing AO7. The developed strategy appears to be promising for enhancing the applicability of laccase in practical water treatment.

  6. Ionic Polymer-Coated Laccase with High Activity and Enhanced Stability: Application in the Decolourisation of Water Containing AO7

    PubMed Central

    Zhang, Xiaolin; Hua, Ming; Lv, Lu; Pan, Bingcai

    2015-01-01

    Eliminating dyes in environmental water purification remains a formidable challenge. Laccase is a unique, environmentally friendly and efficient biocatalyst that can degrade pollutants. However, the use of laccase for the degradation of pollutants is considerably limited by its susceptibility to environmental changes and its poor reusability. We fabricated a novel biocatalyst (LacPG) by coating polyethylenimine onto the native laccase (Lac) followed by crosslinking with glutaraldehyde. The stability of the resulting LacPG was highly enhanced against pH variations, thermal treatments and provided better long-term storage with a negligible loss in enzymatic activity. Compared to Lac, LacPG exhibited significantly higher decolourisation efficiency in the degradation of a representative azo dye, acid orange 7 (AO7), which resulted from the electrostatic attraction between the coating and AO7. LacPG was separated from the AO7 solution using an ultrafiltration unit. The increased size and modified surface chemistry of LacPG facilitated ultrafiltration and reduced membrane fouling. LacPG exhibited enhanced stability, high catalytic activity and favourable properties for membrane separation; therefore, LacPG could be continuously reused in an enzymatic membrane reactor with a high efficiency for decolourising water containing AO7. The developed strategy appears to be promising for enhancing the applicability of laccase in practical water treatment. PMID:25652843

  7. Fine Analysis of 121 Hermione, 45 Eugenia, and 90 Antiope Binary Asteroid Systems With AO Observations

    NASA Astrophysics Data System (ADS)

    Marchis, F.; Descamps, P.; Hestroffer, D.; Berthier, J.; de Pater, I.

    2004-11-01

    We report on a campaign of adaptive optics observations which focuses on 121 Hermione, 45 Eugenia, and 90 Antiope binary asteroids performed with ESO-VLT and Keck II telescopes in 2003-2004. A precessing Keplerian model was used to describe the motion of their companion. The orbital elements are determined accurately using data spanning more than 2 years. The satellite of 121 Hermione revolves at a= 775+/-14 km from the primary in P=2.5714+/-0.001 days with a low eccentricity (e=0.008+/-0.004) and retrograde orbit w.r.t. to the primary's equator (i=175+/-4 deg considering a pole solution (1.9,13.2) deg in ecliptic EQJ2000). The sense of revolution was unambiguously estimated from images separated by a few hours. Keck AO data taken in December 2003 revealed the bi-lobated shape of the primary. The nominal bulk density as derived from observed size of the primary and its 209 km IRAS diameter is 1.2+/-0.3 g/cm3 (Marchis et al., Icarus, 2004). Future observations with better angular resolution will allow us to see if 121 Hermione is a triple system. The orbit of Petit-Prince, moonlet of 45 Eugenia, was constrained using Feb. and Mar. 2004 AO data recorded at the VLT (a=1196+/-4 km, P= 4.7244+/-0.001 days, e=0, i=163+/-6 deg with a pole solution (133+/-3,-40+/-3 deg) in ecliptic B1950), leading to a bulk density of 1.17 g/cm3 considering its 215 km IRAS diameter. Both models predict successfully the positions reported for the discovery of Petit-Prince on Nov. 1998 and of S/2001 (121) 1 by Merline et al. (1999 and 2002). We will also present results on the same-size binary asteroid 90 Antiope, using the same analysis. Feb. and Mar. 2004 VLT-NACO data confirmed that both components are similar (with a Dm 2.4 and a diameter of 110+/-16 km). A preliminary analysis of Feb. and Mar. 2004 VLT data confirms that both components, separated by 170+/-1 km, with a revolution period P=16.5268 +- 0.0001h, are quasi-similar (with a Dm ˜ 2.4% and a diameter of 110+/-16 km) leading to a low bulk density of 0.6+/-0.2 g/cm3. NIR colors, shape of the primary, and motions of the apsidal lines of these binaries will be discussed. This work supported by the National Science Foundation Science and Technology Center for Adaptive Optics, is based on observations collected at the European Southern Observatory, Chile and Keck telescope, Hawaii.

  8. LDEF (Postflight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 EL-1994-00354 LDEF (Postflight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 The postflight photograph was taken in the SAEF II at KSC prior to removal of the experiment from the LDEF. The color of the white paint dots on the exper- iment tray clamp blocks appear to be unchanged. The LDEF structure, the intercostal on the right, has a dark brown discoloration adjacent to the black Earth end thermal panel. Aluminum pieces of the degraded CVCHPE thermal cover that were shown lodged in the vent area between the intercostal and the black thermal panel in the flight photograph are gone. The Cascade Variable Conductance Heat Pipe Experiment (CVCHPE) occupies a 6 inch deep LDEF peripheral experiment tray and consist of two series connected variable conductance heatpipes, a black chrome solar collector panel and a silvered TEFLON® radiator panel, a power source to support six thermistor-type temperature monitoring sensors and actuations of two valves. Fiberglass standoffs and internal insulation blankets thermally isolated the experiment from the experiment tray and the LDEF interior. The outside of the CVCHPE, except the collector and radiator panels, was covered with an aluminized Kapton multilayer insulation (MLI) blanket with an outer layer of 0.076 mm thick Kapton. The two patches of thin film materials, part of Experiment S1001 by NASA GSFC, were attached to the cover of the external thermal blanket with Kapton tape. The experiment was assembled and mounted in the experiment tray with non-magnetic stainless steel fasteners. The external surface of the CVCHPE has changed from that observed in the flight photograph. The thin vapor deposited aluminum coating, left after the Kapton eroded, is essentially gone with only fragments left near the edges of the thermal blanket. Pieces of a layer of Dacron mesh (bridle vail) material, used to separate the thermal cover from the thermal blanket and between thermal blanket sheets of aluminized Kapton, are visible along the edges of the blanket and near Kel-F buttons used to secure the blanket. A large fragment of the material is folded over the left side of the radiator panel. The large area of discoloration on the right side of the black solar absorber panel appears to be approximately the same shape as the aluminum coating that covered the area in the flight photograph. The orientation of the remaining thin film atomic oxygen experiment patch would indicate that the patch is attached to the Dacron mesh and that the attachment is very fragile. The layer of Kapton tape that covered the ends of the thin film strips appears to be eroded with only the adhesive remaining. The remaining strips of the atomic oxygen experiment materials have changed colors and most appear to be severely degraded. The silvered TEFLON® coating of the radiator panel appears diffuse with a light brown discoloration over most of the surface. The white, evenly spaced, discolorations along the horizontal centerline and along the edges of the panel appear to be above counter sunk flat head screws used to assemble the experiment. The black spots on the radiator panel appear to be impact craters that penetrated the TEFLON® material and exposed the silver beneath to the atomic oxygen flux. Particles of the degraded thermal blanket material that appeared to adhere to the surface of the radiator panel in the flight photograph are gone.

  9. LDEF (Flight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 EL-1994-00020 LDEF (Flight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 The flight photograph of the Cascade Variable Conductance Heat Pipe Experiment (CVCHPE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp blocks of the experiment trays right flange and lower flange appear to be slightly discolored. The LDEF structure, top intercostal, has a dark brown discoloration adjacent to the black thermal panel. Aluminum particles from the degraded CVCHPE thermal blanket are also visible in this area. The Cascade Variable Conductance Heat Pipe Experiment (CVCHPE) occupies a 6 inch deep LDEF peripheral experiment tray and consist of two series connected variable conductance heatpipes, a black chrome solar collector panel and a silvered TEFLON® radiator panel, a power source to support six thermistor-type temperature monitoring sensors and actuations of two valves. Fiberglass standoffs and internal insulation blankets thermally isolated the experiment from the experiment tray and the LDEF interior. The outside of the CVCHPE, except the collector and radiator panels, was covered with an aluminumized Kapton multilayer insulation (MLI) blanket with an outer layer of 0.076 mm thick Kapton. The two patches of thin film materials, part of an atomic oxygen experiment (see S1001) by NASA GSFC, were attached to the cover of the external thermal blanket with Kapton tape. The experiment was assembled and mounted in the experiment tray with non-magnetic stainless steel fasteners. The external CVCHPE materials have changed significantly. The Kapton on the thermal blanket aluminized Kapton cover appears to be completely eroded, except under Kel-F buttons used to secure the blanket, leaving only the very thin vapor deposited aluminum coating as a cover. Parts of the aluminum coating residue has moved to cover a portion of the black solar absorber panel and also areas of the trays upper and lower flanges. The shadow on the tray lower flange would indicate that the aluminum extends several inches out of the tray envelope. One of the two thin film atomic oxygen experiment patches is gone and the other does not appear to be securely attached. The layer of Kapton tape over the thin film strips appears to be eroded with only the adhesive remaining. The remaining atomic oxygen experiment materials have changed colors and most appear to be severely degraded. The silvered TEFLON® coating of the radiator panel appears diffuse with a light brown discoloration over most of the surface. The white, evenly spaced, discolorations along the vertical centerline and across the top of the panel appear to be above counter sunk flat head screws used to assemble the experiment. The black spots on the radiator panel appear to be impact craters where the impact penetrated the TEFLON® material and exposed the silver beneath to the atomic oxygen flux. Particles of the degraded thermal blanket material appear to be adhered to the surface of the radiator panel.

  10. Revolutionary visible and infrared sensor detectors for the most advanced astronomical AO systems

    NASA Astrophysics Data System (ADS)

    Feautrier, Philippe; Gach, Jean-Luc; Guieu, Sylvain; Downing, Mark; Jorden, Paul; Rothman, Johan; de Borniol, Eric D.; Balard, Philippe; Stadler, Eric; Guillaume, Christian; Boutolleau, David; Coussement, Jérome; Kolb, Johann; Hubin, Norbert; Derelle, Sophie; Robert, Clélia; Tanchon, Julien; Trollier, Thierry; Ravex, Alain; Zins, Gérard; Kern, Pierre; Moulin, Thibaut; Rochat, Sylvain; Delpoulbé, Alain; Lebouqun, Jean-Baptiste

    2014-07-01

    We report in this paper decisive advance on the detector development for the astronomical applications that require very fast operation. Since the CCD220 and OCAM2 major success, new detector developments started in Europe either for visible and IR wavelengths. Funded by ESO and the FP7 Opticon European network, the NGSD CMOS device is fully dedicated to Natural and Laser Guide Star AO for the E-ELT with strong ESO involvement. The NGSD will be a 880x840 pixels CMOS detector with a readout noise of 3 e (goal 1e) at 700 Hz frame rate and providing digital outputs. A camera development, based on this CMOS device and also funded by the Opticon European network, is ongoing. Another major AO wavefront sensing detector development concerns IR detectors based on Avalanche Photodiode (e- APD) arrays within the RAPID project. Developed by the SOFRADIR and CEA/LETI manufacturers, the latter offers a 320x255 8 outputs 30 microns IR array, sensitive from 0.4 to 3 microns, with less than 2 e readout noise at 1600 fps. A rectangular window can also be programmed to speed up even more the frame rate when the full frame readout is not required. The high QE response, in the range of 70%, is almost flat over this wavelength range. Advanced packaging with miniature cryostat using pulse tube cryocoolers was developed in the frame of this programme in order to allow use on this detector in any type of environment. The characterization results of this device are presented here. Readout noise as low as 1.7 e at 1600 fps has been measured with a 3 microns wavelength cut-off chip and a multiplication gain of 14 obtained with a limited photodiode polarization of 8V. This device also exhibits excellent linearity, lower than 1%. The pulse tube cooling allows smart and easy cooling down to 55 K. Vibrations investigations using centroiding and FFT measurements were performed proving that the miniature pulse tube does not induce measurable vibrations to the optical bench, allowing use of this cooled device without liquid nitrogen in very demanding environmental conditions. A successful test of this device was performed on sky on the PIONIER 4 telescopes beam combiner on the VLTi at ESOParanal in June 2014. First Light Imaging, which will commercialize a camera system using also APD infrared arrays in its proprietary wavefront sensor camera platform. These programs are held with several partners, among them are the French astronomical laboratories (LAM, OHP, IPAG), the detector manufacturers (e2v technologies, Sofradir, CEA/LETI) and other partners (ESO, ONERA, IAC, GTC, First Light Imaging). Funding is: Opticon FP7 from European Commission, ESO, CNRS and Université de Provence, Sofradir, ONERA, CEA/LETI the French FUI (DGCIS), the FOCUS Labex and OSEO.

  11. LDEF (Postflight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 EL-1994-00354 LDEF (Postflight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 The postflight photograph was taken in the SAEF II at KSC prior to removal of the experiment from the LDEF. The color of the white paint dots on the exper- iment tray clamp blocks appear to be unchanged. The LDEF structure, the intercostal on the right, has a dark brown discoloration adjacent to the black Earth end thermal panel. Aluminum pieces of the degraded CVCHPE thermal cover that were shown lodged in the vent area between the intercostal and the black thermal panel in the flight photograph are gone. The Cascade Variable Conductance Heat Pipe Experiment (CVCHPE) occupies a 6 inch deep LDEF peripheral experiment tray and consist of two series connected variable conductance heatpipes, a black chrome solar collector panel and a silvered TEFLON® radiator panel, a power source to support six thermistor-type temperature monitoring sensors and actuations of two valves. Fiberglass standoffs and internal insulation blankets thermally isolated the experiment from the experiment tray and the LDEF interior. The outside of the CVCHPE, except the collector and radiator panels, was covered with an aluminized Kapton multilayer insulation (MLI) blanket with an outer layer of 0.076 mm thick Kapton. The two patches of thin film materials, part of Experiment S1001 by NASA GSFC, were attached to the cover of the external thermal blanket with Kapton tape. The experiment was assembled and mounted in the experiment tray with non-magnetic stainless steel fasteners. The external surface of the CVCHPE has changed from that observed in the flight photograph. The thin vapor deposited aluminum coating, left after the Kapton eroded, is essentially gone with only fragments left near the edges of the thermal blanket. Pieces of a layer of Dacron mesh (bridle vail) material, used to separate the thermal cover from the thermal blanket and between thermal blanket sheets of aluminized Kapton, are visible along the edges of the blanket and near Kel-F buttons used to secure the blanket. A large fragment of the material is folded over the left side of the radiator panel. The large area of discoloration on the right side of the black solar absorber panel appears to be approximately the same shape as the aluminum coating that covered the area in the flight photograph. The orientation of the remaining thin film atomic oxygen experiment patch would indicate that the patch is attached to the Dacron mesh and that the attachment is very fragile. The layer of Kapton tape that covered the ends of the thin film strips appears to be eroded with only the adhesive remaining. The remaining strips of the atomic oxygen experiment materials have changed colors and most appear to be severely degraded. The silvered TEFLON® coating of the radiator panel appears diffuse with a light brown discoloration over most of the surface. The white, evenly spaced, discolorations along the horizontal centerline and along the edges of the panel appear to be above counter sunk flat head screws used to assemble the experiment. The black spots on the radiator panel appear to be impact craters that penetrated the TEFLON® material and exposed the silver beneath to the atomic oxygen flux. Particles of the degraded thermal blanket material that appeared to adhere to the surface of the radiator panel in the flight photograph are gone.

  12. LDEF (Flight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 EL-1994-00020 LDEF (Flight), AO076 : Cascade Variable-Conductance Heat Pipe, Tray F09 The flight photograph of the Cascade Variable Conductance Heat Pipe Experiment (CVCHPE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp blocks of the experiment trays right flange and lower flange appear to be slightly discolored. The LDEF structure, top intercostal, has a dark brown discoloration adjacent to the black thermal panel. Aluminum particles from the degraded CVCHPE thermal blanket are also visible in this area. The Cascade Variable Conductance Heat Pipe Experiment (CVCHPE) occupies a 6 inch deep LDEF peripheral experiment tray and consist of two series connected variable conductance heatpipes, a black chrome solar collector panel and a silvered TEFLON® radiator panel, a power source to support six thermistor-type temperature monitoring sensors and actuations of two valves. Fiberglass standoffs and internal insulation blankets thermally isolated the experiment from the experiment tray and the LDEF interior. The outside of the CVCHPE, except the collector and radiator panels, was covered with an aluminumized Kapton multilayer insulation (MLI) blanket with an outer layer of 0.076 mm thick Kapton. The two patches of thin film materials, part of an atomic oxygen experiment (see S1001) by NASA GSFC, were attached to the cover of the external thermal blanket with Kapton tape. The experiment was assembled and mounted in the experiment tray with non-magnetic stainless steel fasteners. The external CVCHPE materials have changed significantly. The Kapton on the thermal blanket aluminized Kapton cover appears to be completely eroded, except under Kel-F buttons used to secure the blanket, leaving only the very thin vapor deposited aluminum coating as a cover. Parts of the aluminum coating residue has moved to cover a portion of the black solar absorber panel and also areas of the trays upper and lower flanges. The shadow on the tray lower flange would indicate that the aluminum extends several inches out of the tray envelope. One of the two thin film atomic oxygen experiment patches is gone and the other does not appear to be securely attached. The layer of Kapton tape over the thin film strips appears to be eroded with only the adhesive remaining. The remaining atomic oxygen experiment materials have changed colors and most appear to be severely degraded. The silvered TEFLON® coating of the radiator panel appears diffuse with a light brown discoloration over most of the surface. The white, evenly spaced, discolorations along the vertical centerline and across the top of the panel appear to be above counter sunk flat head screws used to assemble the experiment. The black spots on the radiator panel appear to be impact craters where the impact penetrated the TEFLON® material and exposed the silver beneath to the atomic oxygen flux. Particles of the degraded thermal blanket material appear to be adhered to the surface of the radiator panel.

  13. Deriving the True Mass of an Unresolved Brown Dwarf Companion with AO Aided Astrometry

    NASA Astrophysics Data System (ADS)

    Meyer, Eva; Kürster, M.

    2010-01-01

    From radial velocity detections alone one does not get all orbital parameters needed to derive the true mass of a non-transiting, unresolved substellar companion to a star. Additional astrometric measurements are needed to calculate the inclination and the longitude of the ascending node. Until today only few true companion masses have been determined by this method with the HST fine guidance sensor (Benedict 2006, Benedict 2002). We aim to derive the true mass of a brown dwarf candidate companion to an early M 2.5V dwarf with groundbased high-resolution astrometry aided by adaptive optics. We found this unique brown dwarf desert object, which distance to the host star is only 0.42 AU, in our UVES precision radial velocity survey of M dwarfs, inferring a minimum companion mass of 27 Jupiter masses (Kuerster 2008). Combining the data with HIPPARCOS astrometry, we found a probability of only 2.9% that the companion is stellar. We are therefore observing the host star and a reference star within a monitoring program with VLT/NACO to derive the true mass of the companion and establish its nature (BD vs. star). Simultaneous observations of a reference field in a globular cluster are performed to determine the stability of the AO plus detector system and check its suitability for such high-precision astrometric measurements over several epochs which are needed to find and analyse extrasolar planet systems. We present preliminary results of the analysis of the astrometric displacements of the host star due to the unseen companion after correcting for differential refraction and differential aberration, as well as a first orbit fit and mass estimation.

  14. Variability and changes of Arctic sea ice thickness distribution under different AO/DA states

    NASA Astrophysics Data System (ADS)

    Oikkonen, A.; Haapala, J.

    2011-01-01

    Changes of the mean sea ice thickness and concentration in the Arctic are well known. However, comparable little is known about the ice thickness distribution and the composition of ice pack in quantity. In this paper we determine the ice thickness distributions, mean and modal thicknesses, and their regional and seasonal variability in the Arctic under different large scale atmospheric circulation modes. We compare characteristics of the Arctic ice pack during the periods 1975-1987 and 1988-2000, which have a different distribution in the AO/DA space. The study is based on submarine measurements of sea ice draft. The prevalent feature is that the peak of sea ice thickness distributions has generally taken a narrower form and shifted toward thinner ice. Also, both mean and modal ice thickness have generally decreased. These noticeable changes result from a loss of thick, mostly deformed, ice. In the spring the loss of the volume of ice thicker than 5 m exceeds 35% in all regions except the Nansen Basin, and the reduction is as much as over 45% at the North Pole and in the Eastern Arctic. In the autumn the volume of thick, mostly deformed ice has decreased by more than 40% in the Canada Basin only, but the reduction is more than 30% also in the Beaufort Sea and in the Chukchi Sea. In the Beaufort Sea region the decrease of the modal draft has been so strong that the peak has shifted from multiyear ice to first-year type ice. Also, the regional and seasonal variability of the sea ice thickness has decreased, since the thinning has been the most pronounced in the regions with the thickest pack ice (the Western Arctic), and during the spring (0.6-0.8 m per decade).

  15. Hybrid External Fixation for Arbeitsgemeinschaft für Osteosynthesefragen (AO) 43-C Tibial Plafond Fractures.

    PubMed

    Abd-Almageed, Emad; Marwan, Yousef; Esmaeel, Ali; Mallur, Amarnath; El-Alfy, Barakat

    2015-01-01

    Arbeitsgemeinschaft für Osteosynthesefragen (AO) type 43-C tibial plafond/pilon fractures represent a challenge for the treating orthopedic surgeon. We assessed the outcomes of using hybrid external fixation for this fracture type. The present prospective cohort study was started in August 2009 and ended by July 2012. Thirty consecutive patients (mean age 37.4 ± 10.7 years) with a type C tibial plafond fracture who had presented to our tertiary care orthopedic hospital were included. Motor vehicle accidents and fall from height were the cause of the fracture in 14 (46.7%) and 13 (43.3%) patients, respectively. A type C3 fracture was present in 25 patients (83.3%), and type C1 and C2 fractures were present in 2 (6.7%) and 3 (10.0%) patients, respectively. Nine fractures (30.0%) were open. Hybrid external fixation was used for all fractures. All fractures were united; clinical healing was achieved by a mean of 18.1 ± 2.2 weeks postoperatively and radiologic healing at a mean of 18.9 ± 1.9 weeks. The fixator was removed at a mean of 20.4 ± 2.0 weeks postoperatively. At a mean follow-up point of 13.4 ± 2.6 months, the mean modified Mazur ankle score was 84.6 ± 10.4. It was not associated with wound classification (p = .256). The most commonly seen complication was ankle osteoarthritis (17 patients; 56.7%); however, it was mild in >50.0% of the affected patients. In conclusion, using hybrid external fixation for type C tibial plafond fractures resulted in good outcomes. However, this should be investigated further in studies with a higher level of evidence. PMID:26215549

  16. Climate Factors as Important Determinants of Dengue Incidence in Curaçao.

    PubMed

    Limper, M; Thai, K T D; Gerstenbluth, I; Osterhaus, A D M E; Duits, A J; van Gorp, E C M

    2016-03-01

    Macro- and microclimates may have variable impact on dengue incidence in different settings. We estimated the short-term impact and delayed effects of climate variables on dengue morbidity in Curaçao. Monthly dengue incidence data from 1999 to 2009 were included to estimate the short-term influences of climate variables by employing wavelet analysis, generalized additive models (GAM) and distributed lag nonlinear models (DLNM) on rainfall, temperature and relative humidity in relation to dengue incidence. Dengue incidence showed a significant irregular 4-year multi-annual cycle associated with climate variables. Based on GAM, temperature showed a U-shape, while humidity and rainfall exhibited a dome-shaped association, suggesting that deviation from mean temperature increases and deviation from mean humidity and rainfall decreases dengue incidence, respectively. Rainfall was associated with an immediate increase in dengue incidence of 4.1% (95% CI: 2.2-8.1%) after a 10-mm increase, with a maximum increase of 6.5% (95% CI: 3.2-10.0%) after 1.5 month lag. A 1°C decrease of mean temperature was associated with a RR of 17.4% (95% CI: 11.2-27.0%); the effect was inversed for a 1°C increase of mean temperature (RR= 0.457, 95% CI: 0.278-0.752). Climate variables are important determinants of dengue incidence and provide insight into its short-term effects. An increase in mean temperature was associated with lower dengue incidence, whereas lower temperatures were associated with higher dengue incidence. PMID:26122819

  17. Postoperative bedrest improves the alignment of thoracolumbar burst fractures treated with the AO spinal fixator

    PubMed Central

    Dang, Yen; Yen, David; Hopman, Wilma M.

    2009-01-01

    Background A loss of reduction due to inadequate support of the anterior column when using short-segment instrumentation to treat burst fracture and novel methods for support of the anterior column through a posterior approach to augment posterior instrumentation have been reported in the literature. We hypothesized that if anterior column support is an important adjunct to posterior short-segment instrumentation, then avoidance of axial load until sufficient anterior column healing occurs, allowing load-sharing with the implant, would improve spinal alignment at follow-up. Methods We conducted a retrospective cohort study in which consecutive patients who had instrumentation and fusion with the AO spinal fixator were immediately ambulated after surgery or had 4 weeks of bedrest. We measured kyphosis and wedge angles preoperatively, immediately postoperatively and at the time of final follow-up. We used radiologic measures to assess instrumentation and bone failure. Results We found significant differences in the mean loss of wedge and kyphosis angle correction between patients immediately ambulated and those who had 4 weeks of bedrest (0.71º v. ? 4.73º for wedge and 1.81º v. ? 6.55º for kyphosis, respectively). There was significant correlation between instrumentation and bone failure in both the immediate ambulation and bedrest groups. Conclusion Bedrest improves the maintenance of intraoperative sagittal alignment correction, which is in agreement with the theory that inadequate support of the anterior spinal column is the mechanism for loss of reduction when using short-segment instrumentation to treat burst fractures. Therefore, addressing the anterior column directly through anterior surgery or by employing novel techniques in posterior surgery is recommended if one of the goals of treatment is to maintain the sagittal correction achieved at the time of surgery. Trying to achieve this goal by addressing posterior implant design or bone quality alone will not be successful because instrumentation and bone failure occur together. PMID:19503666

  18. Diferentes metodologias aplicadas ao ensino de astronomia no Ensino Médio

    NASA Astrophysics Data System (ADS)

    Albrecht, E.; Voelzke, M. R.

    2009-03-01

    O presente trabalho de intervenção foi realizado junto à Escola Estadual Colònia dos Pescadores na cidade de Caraguatatuba, com très turmas do terceiro ano do Ensino Médio, envolvendo 119 alunos com idades entre 16 e 19 anos. A fase inicial foi composta de um questionário de vinte questíes dissertativas e objetivas, aplicado pelo professor titular da sala, que era o mesmo nas très turmas, para diagnosticar nos educandos os conceitos prévios sobre Astronomia e, partindo destes realizar um trabalho de intervenção nas classes envolvidas utilizando, em cada uma, metodologias diferentes: (A) sob forma de seminários, elaborados e apresentados pelos educandos, no qual o educador faz apenas as intervençíes necessárias; (B) de forma tradicional, com auxílio de multimídias para desenvolvimento das aulas e a terceira (C) tradicional, fazendo uso exclusivo de lousa e giz. Ao final do trabalho os alunos responderam novamente o questionário inicial para diagnosticar dentre as très metodologias utilizadas qual apresentou melhores aplicaçíes, os resultados iniciais foram comparados com os finais. Quando questionados a respeito do significado de Astronomia observou-se inicialmente que os acertos na turma A foram de 100%, turma B: 64%, turma C: 84%, após a intervenção os acertos foram: 100%, 97% e 85% respectivamente, demonstrando que houve um avanço significativo na turma B, a turma A manteve seu índice e a turma C evoluiu, porém não tanto quanto a B. Quando interrogados sobre quantos planetas vocè acha que existem em nosso Sistema Solar? os acertos foram: turma A: 39%, turma B: 48% e turma C: 46%, após o desenvolvimento do trabalho os acertos foram 94%, 97% e 90% respectivamente. Dentro das respostas obtidas observa-se que a metodologia tradicional com o auxílio de multimeios, aplicada na turma B, demonstrou melhores resultados, sendo a mais significativa. Outra conclusão muito importante é que apesar de o tema Astronomia ser amplamente recomendado, este não é ensinado, nem no Ensino Fundamental, nem no Ensino Médio.

  19. The potential of GPI extreme AO system to image and characterize exoplanets and asteroids

    NASA Astrophysics Data System (ADS)

    Marchis, Franck; Vega, David

    2014-11-01

    The Gemini Planet Imager (GPI) is a next-generation adaptive optics coronagraph designed for direct imaging and spectroscopy of extrasolar planets, polarimetry of circumstellar disks and solar system planets. It is the first such facility-class instrument deployed on a 8-m telescope, designed to achieve contrast levels of up to 10^7.On the first commissioning observations (2013B), we achieved an estimated H band Strehl ratio of 0.89 and a 5-sigma contrast of 10^6 at 0.75 arcseconds. Observations of Beta Pictoris (Macintosh et al. PNAS 2014) clearly detect the planet, Beta Pictoris b, in a single 60-second exposure with minimal post-processing. These observations were taken covering the H-band (1.65 ?m). A H-band spectrum of Beta Pic b presented in Chilcote et al. (2014) with a resolving power of ~45 and demonstrates the distinctive triangular shape of a cool substellar object with low surface gravity leading to an effective temperature of 1650+/-50 K and a surface gravity of log(g) = 4.0 +/- 0.25 (cgs units).We will also present the analysis of observations of (2) Pallas observed in direct imaging (without coronagraph) on March 22 2014 in Y, J, H, and K1 filters (from 0.95 to 2.19 ?m) spectroscopically with a resolution varying from 34 to 70. The 540-km asteroid is well resolved and irregular. An ellipse of 540±9 mas and 470±9 mas fits its silhouette. The surface of the asteroid is mostly featureless but small differences of colors is currently being analyzed. No moons with a diameter larger than 2 km and at least 480 km from Pallas were detected on these observations.These results show the power of a dedicated extreme AO with high-contrast imager, low resolution spectrograph and polarizer. A 600-star survey of young nearby stars led by B. Macintosh will begin in 2014B to produce a sample of directly imaged planets that spans a broad range of temperatures, ages, and masses and probes the range of semi-major-axes and stellar ages inaccessible to Doppler and transit surveys. Similarly a program to map ~30-40 large main-belt asteroids and search for companions around them will be initiated in 2015A. This work is funded by NASA NNX14AJ80G

  20. Future change of water vaiables from HadGEM2-AO simulation

    NASA Astrophysics Data System (ADS)

    Kim, Moon-Hyun; Kang, Hyun-Suk; Lee, Johan; Baek, Hee-Jeong; Cho, Chunho

    2013-04-01

    Complex global models developed for climate prediction are now applied to the future climate projection in a number of global modeling centers around the world. In climate prediction aspects, an atmosphere-ocean coupled model (one-tier climate system) has been recognized to exhibit useful skill for a global or certain regions (Graham et al., 2005). Wang et al. (2005) demonstrates that an AGCM coupled with an ocean model, simulates realistic SST-rainfall relationships for the Asia during the summer period. Also the transition from two-tier to one-tier approach in climate prediction are mainly caused by recent progresses in development of coupled climate models and enlargement of understanding air-sea interactions obtained from international collaborative efforts such as TOGA (the Tropical Ocean-Global Atmosphere) program (Wang et al., 2009). Meanwhile, water resource including river outflow in association with surface and sub-surface water flow is an important part of the global hydrological cycle, and is affected by climate variability and change through recharge processes (Chen et al., 2002), as well as by human interventions in many locations (Petheram et al., 2001). Also, water is critical resource to the social, economic and environmental aspects, and advances of these core elements requires improved water resource management. Better management and use of water need to abundant real time hydro-meteorological (river and weather) information as well as accurate water resource forecasting (Barrett, 1990). For this reason, many studies have recently carrying out the water resource prediction and estimation using hydrology and climate model. For example, Shiklomanov et al. (2011) predicted that water resource in Russian territory increases about 8-10% during 2010-2020 using the unit hydrograph (UH) model based on hydrologic rainfall-runoff model. Anderson et al. (2000) explained the probabilistic seasonal prediction of drought with a simplified climate model coupled hydrology-atmosphere for water resource planning. Arora et al. (1999) and Oki and Sud (1998) developed a method for routing river flows through GCM grid cells. Accordingly, reliable forecasts are expected to help water managers and users with long lead time decisions, leading to greater water use efficiency and better risk management (Wang, 2012). SO, we analysed hydrological cycle and drought index from precipitation, evaporation, runoff, soil moisture, river outflow, and so on using atmosphere-ocean coupled model which called by HadGEM2-AO. Details and added information by this climate projection system about the future water cycle's change will be presented at the workshop. Acknowledgments: This research has been supported by project NIMR-2013-B-2 of the National Institute of Meteorological Research in Korea Meteorological Administration.

  1. Triangular covariance factorizations for. Ph.D. Thesis. - Calif. Univ.

    NASA Technical Reports Server (NTRS)

    Thornton, C. L.

    1976-01-01

    An improved computational form of the discrete Kalman filter is derived using an upper triangular factorization of the error covariance matrix. The covariance P is factored such that P = UDUT where U is unit upper triangular and D is diagonal. Recursions are developed for propagating the U-D covariance factors together with the corresponding state estimate. The resulting algorithm, referred to as the U-D filter, combines the superior numerical precision of square root filtering techniques with an efficiency comparable to that of Kalman's original formula. Moreover, this method is easily implemented and involves no more computer storage than the Kalman algorithm. These characteristics make the U-D method an attractive realtime filtering technique. A new covariance error analysis technique is obtained from an extension of the U-D filter equations. This evaluation method is flexible and efficient and may provide significantly improved numerical results. Cost comparisons show that for a large class of problems the U-D evaluation algorithm is noticeably less expensive than conventional error analysis methods.

  2. Exotic atoms and leptonic conservations. [Univ. of Wyoming, Laramie, Wyoming

    SciTech Connect

    Kunselman, R.

    1991-01-01

    The major 1989 efforts have been on two aspects of experiments at TRIUMF. One effort was production of muonic hydrogen and muonic deuterium into a vacuum. The study includes rates relevant to muon-catalyzed fusion, and if there are found an adequate number of muons in the 2-S state, then precision energies will be measured. The second effort was to develop plans for kaonic atoms at the kaon factory. In addition, analyses from the experiments with pionic atoms at LAMPF were completed.

  3. Deexcitation processes in nuclear reactions. [Dept. of Chemistry, Purdue Univ

    SciTech Connect

    Porile, N.T.

    1992-09-01

    During the past year, our research program has involved continuing analysis of Fermilab E-735, search for quark-gluon plasma (QGP) in {bar p}-p collisions; continuing study of target fragments produced in the interaction of copper with intermediate-energy heavy ions; an exclusive study of multifragmentation using reverse kinematics at the Bevalac; and detector development for the STAR detector at RHIC.

  4. Research in elementary particle physics. [Ohio State Univ. , Columbus

    SciTech Connect

    Not Available

    1992-01-01

    Experimental and theoretical work on high energy physics is reviewed. Included are preparations to study high-energy electron-proton interactions at HERA, light-cone QCD, decays of charm and beauty particles, neutrino oscillation, electron-positron interactions at CLEO II, detector development, and astrophysics and cosmology.

  5. Nuclear structure studies with medium energy probes. [Northwestern Univ

    SciTech Connect

    Seth, Kamal K.

    1980-01-01

    Progress in the continuing program of experimental research in nuclear structure with medium-energy probes during the year 1979-1980 is reviewed, and the research activities planned for the year 1980-1981 are discussed. In the study of pion-induced reactions emphasis is placed on investigation of isovector characteristics of nuclear excitations and on double charge exchange reactions. Pion production studies form the major part of the program of experiments with proton beams of 400 to 800 MeV at LAMPF. Current emphasis is on the bearing of these investigations on di-baryon existence. The study of high-spin states and magnetic scattering constitute the main goals of the electron scattering program at Bates. Representative results are presented; completed work is reported in the usual publications. (RWR)

  6. Constrained Local UniversE Simulations: A Local Group Factory

    NASA Astrophysics Data System (ADS)

    Carlesi, Edoardo; Sorce, Jenny G.; Hoffman, Yehuda; Gottlöber, Stefan; Yepes, Gustavo; Libeskind, Noam I.; Pilipenko, Sergey V.; Knebe, Alexander; Courtois, Hélène; Tully, R. Brent; Steinmetz, Matthias

    2016-02-01

    Near field cosmology is practiced by studying the Local Group (LG) and its neighbourhood. The present paper describes a framework for simulating the "near field" on the computer. Assuming the ΛCDM model as a prior and applying the Bayesian tools of the Wiener filter (WF) and constrained realizations of Gaussian fields to the Cosmicflows-2 (CF2) survey of peculiar velocities, constrained simulations of our cosmic environment are performed. The aim of these simulations is to reproduce the LG and its local environment. Our main result is that the LG is likely a robust outcome of the LCDM scenario when subjected to the constraint derived from CF2 data, emerging in an environment akin to the observed one. Three levels of criteria are used to define the simulated LGs. At the base level, pairs of halos must obey specific isolation, mass and separation criteria. At the second level the orbital angular momentum and energy are constrained and on the third one the phase of the orbit is constrained. Out of the 300 constrained simulations 146 LGs obey the first set of criteria, 51 the second and 6 the third. The robustness of our LG `factory' enables the construction of a large ensemble of simulated LGs. Suitable candidates for high resolution hydrodynamical simulations of the LG can be drawn from this ensemble, which can be used to perform comprehensive studies of the formation of the nature of the LG.

  7. Research in particle physics. [Dept. of Physics, Boston Univ

    SciTech Connect

    Whitaker, Scott J.

    1992-09-01

    Research accomplishments and current activities of Boston University researchers in high energy physics are presented. Principal areas of activity include the following: detectors for studies of electron[endash]positron annihilation in colliding beams; advanced accelerator component design, including the superconducting beam inflector, electrostatic quadrupoles, and the electrostatic muon kicker''; the detector for the MACRO (Monopole, Astrophysics, and Cosmic Ray Observatory) experiment; neutrino astrophysics and the search for proton decay; theoretical particle physics (electroweak and flavor symmetry breaking, hadron collider phenomenology, cosmology and astrophysics, new field-theoretic models, nonperturbative investigations of quantum field theories, electroweak interactions); measurement of the anomalous magnetic moment of the muon; calorimetry for the GEM experiment; and muon detectors for the GEM experiment at the Superconducting Super Collider.

  8. Relativistic blast-wave model for the rapid flux variations of AO 0235+164 and other compact radio sources

    NASA Technical Reports Server (NTRS)

    Marscher, A. P.

    1978-01-01

    A relativistic blast-wave version of a signal-screen model is developed which can adequately explain the details of the flux-density and structural variations of compact extragalactic radio sources. The relativistic motion implied by flux variations is analyzed with respect to the synchrotron spectrum of the BL Lac object AO 0235+164 observed during outbursts, and a signal-screen model for rapidly expanding shells produced by ultrarelativistic blast waves is examined. The approximate observed structure of the blast wave at three stages in its evolution is illustrated, each stage is described, and the model is applied to the flux density outburst in AO 0235+164 observed in late 1975. The results show that a relativistic blast-wave model can in general reproduce the main features of the observed flux variations in compact sources. Some problems with the proposed model are briefly discussed.

  9. First light curve analyses of binary systems AO Aqr, CW Aqr and ASAS 012206-4924.7

    NASA Astrophysics Data System (ADS)

    Ulaş, B.; Ulusoy, C.

    2015-11-01

    Using the data from the public database of the All Sky Automated Survey (ASAS) we performed the very first light curve analyses of the three eclipsing binary systems AO Aqr, CW Aqr and ASAS 012206-4924.7. The physical parameters of the systems were determined by the PHOEBE (Prša and Zwitter, 2005) software. From an analysis of the ASAS data it was concluded that AO Aqr was found to be a contact binary system while CW Aqr and ASAS 012206-4924.7 were found to be near-contact and detached binaries, respectively. Finally, the locations of the components, corresponding to the estimated physical parameters, in the HR diagram were also discussed.

  10. AoRim15 is involved in conidial stress tolerance, conidiation and sclerotia formation in the filamentous fungus Aspergillus oryzae.

    PubMed

    Nakamura, Hidetoshi; Kikuma, Takashi; Jin, Feng Jie; Maruyama, Jun-Ichi; Kitamoto, Katsuhiko

    2016-04-01

    The serine-threonine kinase Rim15p is a master regulator of stress signaling and is required for stress tolerance and sexual sporulation in the yeast Saccharomyces cerevisiae. However, in filamentous fungi that reproduce asexually via conidiation, the physiological function of Rim15p homologs has not been extensively analyzed. Here, we functionally characterized the protein homolog of Rim15p in the filamentous fungus Aspergillus oryzae, by deleting and overexpressing the corresponding Aorim15 gene and examining the role of this protein in stress tolerance and development. Deletion of Aorim15 resulted in an increase in the sensitivity of conidia to oxidative and heat stresses, whereas conidia of the Aorim15 overexpressing strain were more resistant to these stresses. These results indicated that AoRim15 functions in stress tolerance, similar to S. cerevisiae Rim15p. Phenotypic analysis revealed that conidiation was markedly reduced by overexpression of Aorim15 in A. oryzae, and was completely abolished in the deletion strain. In addition, the formation of sclerotia, which is another type of developmental structure in filamentous fungi, was decreased by the deletion of Aorim15, whereas Aorim15 overexpression increased the number of sclerotia. These results indicated that AoRim15 is a positive regulator of sclerotia formation and that overexpression of AoRim15 shifts the developmental balance from conidiation towards sclerotia formation. Collectively, we demonstrated that AoRim15 is involved in the stress tolerance of conidia and differentially regulates between the two developmental fates of conidiation and sclerotia formation. PMID:26467693

  11. Tolerancing the fabrication errors of static optical elements for ELT-size wide-field AO systems

    NASA Astrophysics Data System (ADS)

    Véran, Jean-Pierre; Pazder, John; Herriot, Glen; Andersen, David

    2012-07-01

    Advanced wide-field AO systems, such as Multi-Conjugate AO (MCAO) systems often require many static optical elements (mirror and lenses) in addition to the active ones (deformable mirrors). These static elements induce additional wave-front errors due to random fabrication errors such as polishing errors. For ELT-size AO systems, these optical elements can be very large, and thus their cost and availability critically depends on how of much fabrication error can be tolerated. Therefore, a rigorous tolerance analysis is absolutely critical. Requirements can, in principle be relaxed, on account that fabrication errors with spatial scales larger than the inter-actuator spacing of the deformable mirrors (DMs) can be corrected. However, this process is significantly complicated by the fact that these optical elements are often conjugated far away from the DMs, and therefore DM correction cannot be achieved over a wide field of view (FOV). In this paper, we present our tolerance analysis in the context of NFIRAOS, the first-light MCAO system for the Thirty Meter Telescope. We start from two top-level error budgets: the “on-axis” error budget, which specifies the acceptable residual wave-front error in the narrow 17”x17” science FOV; and the “off-axis” error budget, which specifies the acceptable residual wave-front error at the edge of the 2’ diameter technical FOV. The former directly relates to science image quality, whereas the latter directly relates to sky coverage. For different assumptions on the spatial power spectrum of the polishing errors, we derive the requirements on each optical element in NFIRAOS using a Monte-Carlo analysis of the predicted off-axis performance of the system with on axis AO correction.

  12. Immunohistochemical analysis of the A4 and AO10 (gp110) cell-surface antigens of human astrocytoma.

    PubMed Central

    Garin-Chesa, P.; Beresford, H. R.; Walker, S.; Rettig, W. J.

    1990-01-01

    The A4 and AO10 (110 kd glycoprotein) cell-surface antigens are biochemically distinct markers of cultured human astrocytomas that are expressed by only a limited number of other cultured cell types. To further characterize these two antigens, the authors used immunohistochemical methods to determine their expression in normal human tissues, astrocytomas, and over 100 tumors of other histologic types. They found that A4 is expressed 1) throughout the central (CNS), but not peripheral nervous system (PNS); 2) in smooth muscle and a small number of epithelial tissues; and 3) in reactive glia and in astrocytomas, but not in most tumors of other histologic types. In contrast, the AO10 antigen is expressed 1) in a small subset of CNS neurons, but not in astrocytes, PNS neurons, or other normal tissues; 2) in astrocytomas and reactive glia; and 3) in some additional neuroectodermal tumors, but not melanomas, carcinomas, or sarcomas. These findings show that A4 and AO10 are restricted markers for human astrocytomas in vivo. Furthermore, the antigens show distinct patterns of expression in normal human CNS but appear to be coordinately expressed in astrocytomas and astrocytoma-derived cell lines. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:2183624

  13. Open-loop control of SCExAO's MEMS deformable mirror using the Fast Iterative Algorithm: speckle control performances

    NASA Astrophysics Data System (ADS)

    Blain, Célia; Guyon, Olivier; Martinache, Frantz; Bradley, Colin; Clergeon, Christophe

    2012-07-01

    Micro-Electro-Mechanical Systems (MEMS) deformable mirrors (DMs) are widely utilized in astronomical Adaptive Optics (AO) instrumentation. High precision open-loop control of MEMS DMs has been achieved by developing a high accuracy DM model, the Fast Iterative Algorithm (FIA), a physics-based model allowing precise control of the DM shape. Accurate open-loop control is particularly critical for the wavefront control of High- Contrast Imaging (HCI) instruments to create a dark hole area free of most slow and quasi-static speckles which remain the limiting factor for direct detection and imaging of exoplanets. The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system is one of these high contrast imaging instruments and uses a 1024-actuator MEMS deformable mirror (DM) both in closed-loop and open-loop. The DM is used to modulate speckles in order to distinguish (i) speckles due to static and slow-varying residual aberrations from (ii) speckles due to genuine structures, such as exoplanets. The FIA has been fully integrated into the SCExAO wavefront control software and we report the FIA’s performance for the control of speckles in the focal plane.

  14. HIGH RESOLUTION H{alpha} IMAGES OF THE BINARY LOW-MASS PROPLYD LV 1 WITH THE MAGELLAN AO SYSTEM

    SciTech Connect

    Wu, Y.-L.; Close, L. M.; Males, J. R.; Follette, K.; Morzinski, K.; Kopon, D.; Rodigas, T. J.; Hinz, P.; Puglisi, A.; Esposito, S.; Pinna, E.; Riccardi, A.; Xompero, M.; Briguglio, R.

    2013-09-01

    We utilize the new Magellan adaptive optics system (MagAO) to image the binary proplyd LV 1 in the Orion Trapezium at H{alpha}. This is among the first AO results in visible wavelengths. The H{alpha} image clearly shows the ionization fronts, the interproplyd shell, and the cometary tails. Our astrometric measurements find no significant relative motion between components over {approx}18 yr, implying that LV 1 is a low-mass system. We also analyze Large Binocular Telescope AO observations, and find a point source which may be the embedded protostar's photosphere in the continuum. Converting the H magnitudes to mass, we show that the LV 1 binary may consist of one very-low-mass star with a likely brown dwarf secondary, or even plausibly a double brown dwarf. Finally, the magnetopause of the minor proplyd is estimated to have a radius of 110 AU, consistent with the location of the bow shock seen in H{alpha}.

  15. ShaneAO: an enhanced adaptive optics and IR imaging system for the Lick Observatory 3-meter telescope

    NASA Astrophysics Data System (ADS)

    Kupke, Renate; Gavel, Donald; Roskosi, Constance; Cabak, Gerald; Cowley, David; Dillon, Daren; Gates, Elinor L.; McGurk, Rosalie; Norton, Andrew; Peck, Michael; Ratliff, Christopher; Reinig, Marco

    2012-07-01

    The Lick Observatory 3-meter telescope has a history of serving as a testbed for innovative adaptive optics techniques. In 1996, it became one of the first astronomical observatories to employ laser guide star (LGS) adaptive optics as a facility instrument available to the astronomy community. Work on a second-generation LGS adaptive optics system, ShaneAO, is well underway, with plans to deploy on telescope in 2013. In this paper we discuss key design features and implementation plans for the ShaneAO adaptive optics system. Once again, the Shane 3-m will host a number of new techniques and technologies vital to the development of future adaptive optics systems on larger telescopes. Included is a woofer-tweeter based wavefront correction system incorporating a voice-coil actuated, low spatial and temporal bandwidth, high stroke deformable mirror in conjunction with a high order, high bandwidth MEMs deformable mirror. The existing dye laser, in operation since 1996, will be replaced with a fiber laser recently developed at Lawrence Livermore National Laboratories. The system will also incorporate a high-sensitivity, high bandwidth wavefront sensor camera. Enhanced IR performance will be achieved by replacing the existing PICNIC infrared array with an Hawaii 2RG. The updated ShaneAO system will provide opportunities to test predictive control algorithms for adaptive optics. Capabilities for astronomical spectroscopy, polarimetry, and visible-light adaptive optical astronomy will be supported.

  16. Modeling the effect of high altitude turbulence in wide-field correlating wavefront sensing and its impact on the performance of solar AO systems

    NASA Astrophysics Data System (ADS)

    Montilla, I.; Tallon, M.; Langlois, M.; Béchet, C.; Collados Vera, M.

    2014-08-01

    Solar Adaptive Optics (AO) shares many issues with night-time AO, but it also has its own particularities. The wavefront sensing is performed using correlations to efficiently work on the solar granulation as a reference. The field of view for that measurement usually is around 10". A sensor collecting such a wide field of view averages wavefront information from different sky directions, and the anisoplanatism thus has a peculiar impact on the performance of solar AO and MCAO systems. Since we are entering the era of large solar telescopes (European Solar Telescope, Advanced Technology Solar Telescope) understanding this issue is crucial to evaluate its impact on the performance of future AO systems. In this paper we model the correlating wide field sensor and the way it senses the high altitude turbulence. Thanks to this improved modelling, we present an analysis of the influence of this sensing on the performance of each AO configuration, conventional AO and MCAO. In addition to the analytical study, simulations similar to the case of the EST AO systems with FRiM-3D (the Fractal Iterative Method for Atmospheric tomography) are used in order to highlight the relative influence of design parameters. In particular, results show the performance evolution when increasing the telescope diameter. We analyse the effect of high altitude turbulence correlation showing that increasing the diameter of the telescope does not degrade the performance when correcting on the same spatial and temporal scales.

  17. Design, Implementation, and On-Sky Performance of an Advanced Apochromatic Triplet Atmospheric Dispersion Corrector for the Magellan Adaptive Optics System and VisAO Camera

    NASA Astrophysics Data System (ADS)

    Kopon, Derek; Close, Laird M.; Males, Jared R.; Gasho, Victor

    2013-08-01

    We present the novel design, laboratory verification, and on-sky performance of our advanced triplet atmospheric dispersion corrector (ADC), an important component of the Magellan Adaptive Optics system (MagAO), which recently achieved first light in December 2012. High-precision broadband (0.5--1.0 ?m) atmospheric dispersion correction at visible wavelengths is essential both for wavefront sensing (WFS) on fainter guide stars, and for performing visible AO science using our VisAO science camera. At 2 airmasses (60° from zenith) and over the waveband 500--1000 nm, our triplet design produces a 57% improvement in geometric rms spot size, a 33% improvement in encircled energy at 20? radius, and a 62% improvement in Strehl ratio when compared to a conventional doublet design. This triplet design has been fabricated, tested in the lab, and integrated into the MagAO WFS and the VisAO science camera. We present on-sky results of the ADC in operation with the MagAO system. We also present a zero-beam-deviation triplet ADC design, which will be important to future AO systems that require precise alignment of the optical axis over a large range of airmasses in addition to diffraction-limited broadband dispersion correction.

  18. Clinical Utility of Electrocochleography in the Diagnosis and Management of Meniere's Disease: AOS and ANS Membership Survey Data

    PubMed Central

    Nguyen, Linda T.; Harris, Jeffrey P.; Nguyen, Quyen T.

    2010-01-01

    Objective Evaluate the clinical utility of electrocochleography (ECoG) for diagnosis/treatment of Meniere’s disease among members of the American Otological Society (AOS) and American Neurotology Society (ANS). Subjects Clinically active members of the AOS/ANS. Main Outcome Measure Survey responses. Results A total of 143 responses were received from 344 possible respondents (41.6%). In suspected cases of Meniere’s disease, 45.5% of respondents did not use ECoG at all, 17.5 % used ECoG routinely, and 37.1% used it only in questionable cases. ECoG users differed widely in electrode approach and stimulus modality used, with extratympanic approach and click stimuli used most frequently. A majority of respondents (73.2%) believed that ECoG is a test of indeterminate value. Only 3.6% required an abnormal ECoG to diagnose endolymphatic hydrops. An abnormal test was a requirement to proceed with ablative therapy for just 8.6% of respondents. Still, 77.9% believe that ECoG findings do fluctuate with activity of the disorder, but only 18.0% agree that when the ECoG reverts to normal, one can predict remission of symptoms. Almost half of respondents (46.7%) reported that they have now stopped ordering ECoG due to variability in results and lack of correlation with their patients’ symptoms. Conclusion Among AOS/ANS members, there is low clinical utility of ECoG in diagnosis/management of Meniere’s disease. For approximately half of respondents, ECoG has no role in their clinical practice. ECoG was used routinely by only one in six respondents. Those who used ECoG differed widely in electrode placement and type of stimuli paradigm used. PMID:20104195

  19. Imaging the living retina at the cellular level with AO parallel spectral-domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Miller, Donald T.; Zhang, Yan; Rha, Jungtae; Jonnal, Ravi S.; Gao, Weihua

    2005-12-01

    We investigate a novel camera that incorporates adaptive optics (AO) and optical coherence tomography (OCT) to determine if it can achieve the necessary 3-D resolution, sensitivity, and speed for imaging individual cells in the living human retina. An AO spectral-domain OCT system was constructed that is based on a free-space Michelson interferometer design. The OCT sub-system consists of a broadband superluminescent diode whose beam passes through an astigmatic lens to form a line illumination pattern on the retina, which is then imaged onto the slit of an imaging spectrometer. The detector of the spectrometer is a scientific-grade areal CCD. Conventional flood illumination, also with AO, was integrated into the camera and provided confirmation of the focus position in the retina. Short bursts of narrow B-scans (100x560 microns) of the living retina were subsequently acquired at 500 Hz during dynamic compensation that corrected the most significant ocular aberrations across a dilated 6 mm pupil. Camera sensitivity (up to 94 dB) was sufficient for observing reflections from essentially all neural layers of the retina. The 3-D resolution of the B-scans (3.0x3.0x5.7 microns) is the highest reported to date in the living human eye. It was sufficient to observe the interface between the inner and outer segments of individual photoreceptor cells, resolved in both lateral and axial dimensions. The waveguiding nature of the photoreceptors is suggestive at multiple reflective sites. Micro-movements of the retina during short burst imaging allow averaging to reduce speckle contrast, but they appear insufficient for significant speckle reduction.

  20. Laboratory results and status update for Pathfinder, the LINC-NIRVANA NGS ground-layer AO subsystem

    NASA Astrophysics Data System (ADS)

    Kopon, Derek; Conrad, Al; Bertram, Thomas; Herbst, Tom; Kürster, Martin; Berwein, Juergen; Ragazzoni, Roberto; Farinato, Jacopo; Viotto, Valentina; Bergomi, Maria; Rohloff, Ralf-Rainer; Baumeister, Harald; De Bonis, Fulvio; Hofferbert, Ralph; Brunelli, Alessandro; Arcidiacono, Carmelo; Pott, Jörg-Uwe; Bizenberger, Peter; Briegel, Florian; Meschke, Daniel; Mohr, Lars; Zhang, Xianyu; Kittmann, Frank

    2013-12-01

    The full LINC-NIRVANA instrument will be one of the most complex ground-based astronomical systems ever built. It will consist of multiple subsystems, including two multi-conjugate ground layer AO systems (MCAO) that drive the LBT adaptive secondaries, two mid-high layer AO systems with their own Xynetics 349 actuator DM's, a fringe tracker, and a beam combiner. In order to mitigate risk, we take a modular approach to instrument testing and commissioning by decoupling these subsystems individually. The first subsystem tested on-sky will be one of the ground-layer AO systems, part of a test-bed known as the Pathfinder. The Pathfinder consists of a 12-star pyramid WFS that drives one of the LBT's adaptive secondaries, a support structure known as "The Foot," and the infrared test camera (IRTC), which is used for acquisition and alignment. The 12 guide stars are acquired by moveable arms called "star enlargers," each of which contains its own optical path. The Pathfinder will be shipped from MPIA in Heidelberg, Germany to the LBT mountain lab on Mt. Graham, Arizona in February. The system will be unpacked, assembled in the LBT clean room, and internally optically aligned. We present the results of our system tests, including star enlarger alignment and system alignment. We also present our immediate plans for on-sky closed loop tests on the LBT scheduled for early Fall. Because plans for all ELTs call for ground layer correction, the Pathfinder provides valuable preliminary information not only for the full LINC-NIRVANA system, but also for future advanced MCAO systems.

  1. A novel mammalian expression system derived from components coordinating nicotine degradation in arthrobacter nicotinovorans pAO1

    PubMed Central

    Malphettes, Laetitia; Weber, Cornelia C.; El-Baba, Marie Daoud; Schoenmakers, Ronald G.; Aubel, Dominique; Weber, Wilfried; Fussenegger, Martin

    2005-01-01

    We describe the design and detailed characterization of 6-hydroxy-nicotine (6HNic)-adjustable transgene expression (NICE) systems engineered for lentiviral transduction and in vivo modulation of angiogenic responses. Arthrobacter nicotinovorans pAO1 encodes a unique catabolic machinery on its plasmid pAO1, which enables this Gram-positive soil bacterium to use the tobacco alkaloid nicotine as the exclusive carbon source. The 6HNic-responsive repressor-operator (HdnoR-ONIC) interaction, controlling 6HNic oxidase production in A.nicotinovorans pAO1, was engineered for generic 6HNic-adjustable transgene expression in mammalian cells. HdnoR fused to different transactivation domains retained its ONIC-binding capacity in mammalian cells and reversibly adjusted transgene transcription from chimeric ONIC-containing promoters (PNIC; ONIC fused to a minimal eukaryotic promoter [Pmin]) in a 6HNic-responsive manner. The combination of transactivators containing various transactivation domains with promoters differing in the number of operator modules as well as in their relative inter-ONIC and/or ONIC-Pmin spacing revealed steric constraints influencing overall NICE regulation performance in mammalian cells. Mice implanted with microencapsulated cells engineered for NICE-controlled expression of the human glycoprotein secreted placental alkaline phosphatase (SEAP) showed high SEAP serum levels in the absence of regulating 6HNic. 6HNic was unable to modulate SEAP expression, suggesting that this nicotine derivative exhibits control-incompatible pharmacokinetics in mice. However, chicken embryos transduced with HIV-1-derived self-inactivating lentiviral particles transgenic for NICE-adjustable expression of the human vascular endothelial growth factor 121 (VEGF121) showed graded 6HNic response following administration of different 6HNic concentrations. Owing to the clinically inert and highly water-soluble compound 6HNic, NICE-adjustable transgene control systems may become a welcome alternative to available drug-responsive homologs in basic research, therapeutic cell engineering and biopharmaceutical manufacturing. PMID:16002786

  2. AO/NAO Response to Climate Change. 2; Relative Importance of Low- and High-Latitude Temperature Changes

    NASA Technical Reports Server (NTRS)

    Rind, D.; Perlwitz, J.; Lonergan, P.; Lerner, J.

    2005-01-01

    Using a variety of GCM experiments with various versions of the GISS model, we investigate how different aspects of tropospheric climate changes affect the extratropical Arctic Oscillation (AO)/North Atlantic Oscillation (NAO) circulation indices. The results show that low altitude changes in the extratropical latitudinal temperature gradient can have a strong impact on eddy forcing of the extratropical zonal wind, in the sense that when this latitudinal temperature gradient increases, it helps force a more negative AO/NAO phase. In addition, local conditions at high latitudes can stabilize/destabilize the atmosphere, inducing negative/positive phase changes. To the extent that there is not a large temperature change in the tropical upper troposphere (either through reduced tropical sensitivity at the surface, or limited transport of this change to high levels), the changes in the low level temperature gradient can provide the dominate influence on the extratropical circulation, so that planetary wave meridional refraction and eddy angular momentum transport changes become uncorrelated with potential vorticity transports. In particular, the climate change that produces the most positive NAO phase change would have substantial warming in the tropical upper troposphere over the Pacific Ocean, with high latitude warming in the North Atlantic. An increase in positive phase of these circulation indices is still more likely than not, but it will depend on the degree of tropical and high latitude temperature response and the transport of low level warming into the upper troposphere. These are aspects that currently differ among the models used for predicting the effects of global warning, contributing to the lack of consensus of future changes in the AO/NAO.

  3. Optimal sensor arrangements in Angle of Arrival (AoA) and range based localization with linear sensor arrays.

    PubMed

    Herath, Sanvidha C K; Pathirana, Pubudu N

    2013-01-01

    This paper investigates the linear separation requirements for Angle-of-Arrival (AoA) and range sensors, in order to achieve the optimal performance in estimating the position of a target from multiple and typically noisy sensor measurements. We analyse the sensor-target geometry in terms of the Cramer-Rao inequality and the corresponding Fisher information matrix, in order to characterize localization performance with respect to the linear spatial distribution of sensors. Here in this paper, we consider both fixed and adjustable linear sensor arrays. PMID:24036585

  4. A new polymer-based laccase for decolorization of AO7: long-term storage and mediator reuse.

    PubMed

    Zhang, Xiaolin; Pan, Bingcai; Wu, Bing; Zhang, Weiming; Lv, Lu

    2014-07-01

    To address the bottlenecks of laccase-based catalysis, i.e., poor long-term stability and potential secondary pollution caused by synthetic mediator, we fabricated a new biocatalyst (N-PS-Lac) through adsorption of laccase onto polystyrene anion exchangers (N-PS) binding quaternary ammonium groups. After 2-year storage, the residual activity of N-PS-Lac remained as high as 101.7%, while that for native laccase was only 14.6%. Also, N-PS-Lac exhibited improved durability against pH variation and thermal treatment at 60°C. Gaussian curve fitting of FT-IR spectra indicated that laccase conformation of N-PS-Lac was rigidified, possibly because of the host geometric restriction and the host-laccase electrostatic attraction. A two-step method, i.e., adsorption of an azo dye AO7 by N-PS and then ectopic degradation by the immobilized laccase, was proposed to reuse the mediator HOBT for seven cyclic runs, where N-PS-Lac kept the constant decolorization efficiency. AO7 solution was detoxified completely after decolorization by the two-step method. PMID:24862000

  5. Simultaneous removal of nutrients from milking parlor wastewater using an AO2 sequencing batch reactor (SBR) system.

    PubMed

    Wu, Xiao; Zhu, Jun

    2015-01-01

    The feasibility of using a lab-scale, anaerobic-aerobic-anoxic-aerobic sequencing batch reactor ((AO)2 SBR) to simultaneously remove biological organics, nitrogen and phosphorus from dairy milking parlor wastewater was investigated in this study. Three hydraulic retention times (HRT = 2.1, 2.7, and 3.5 days) and three mixing-to-process time ratios (TM/TP = 0.43, 0.57, and 0.68) were evaluated as two controlling factors using a 3 × 3 experimental design to determine the optimal combination. Results showed that the HRT of 2.7 days with TM/TP = 0.57 was the best to achieve simultaneous nutrients removal for the influent with initial soluble chemical oxygen demand (SCOD) of about 2000 mg L(-1) (only 0.55 mg L(-1) NH4-N, < 0.1 mg L(-1) nitrate, and 0.14 mg L(-1) soluble phosphorus in the effluent). Good correlations between pH and ORP, and ORP and DO, were also obtained with correlation coefficients all higher than or equal to 0.975. These relationships could be used to develop real-time control strategies to optimize the duration of each operating phase in the (AO)2 SBR system to save energy and enhance treatment efficiency. PMID:25723066

  6. Use of a single 2.0-mm locking AO reconstruction titanium plate in linear, non-comminuted, mandible fractures

    PubMed Central

    Parmar, Babu S.; Makwana, Kalpesh G.; Patel, Aditi M.; Tandel, Ramanuj C.; Shah, Jay

    2014-01-01

    Purpose: The aim of the following study is to prospectively evaluate the use of a single Arbeitsgemeinschaft für Osteosynthesefragen (AO) 2.0-mm locking reconstruction plate for linear non-comminuted mandibular fractures without the use of a second plate. Materials and Methods: This study consisted of a sample of 10 patients who reported to the department with fractures of the mandible and were treated over a period of 24 months from November 2010 to November 2012. Out of these, there were 8 male patients and 2 female patients. There were four cases of isolated parasymphysis fractures, 1 of the case had a parasymphysis fracture associated with subcondylar fracture, 4 had a body fracture and 2 had a symphysis fracture. Results: All patients had satisfactory fracture reduction and a successful treatment outcome without major complications. Only one patient (10%) developed minor complications. Conclusion: The study has demonstrated that treating linear non-comminuted mandibular fractures with a single AO 2.0-mm locking reconstruction plate provides excellent stability at the fracture site which in turn leads to sound bone healing and early functional rehabilitation. PMID:24987599

  7. The Triaxial Ellipsoid Diameters and Rotational Pole of Asteroid (9) Metis from AO at Gemini and Keck

    NASA Astrophysics Data System (ADS)

    Drummond, Jack D.; Merline, W. J.; Conrad, A.; Dumas, C.; Tamblyn, P.; Christou, J.; Carry, B.; Chapman, C.

    2012-10-01

    From Adaptive Optics (AO) images of (9) Metis at 14 epochs over 2008 December 8 and 9 at Gemini North, triaxial ellipsoid diameters of 218x175x112 km are derived with fitting uncertainties of 3x3x47 km. However, by including just two more AO images from Keck-II in June and August of 2003 in a global fit, the fitting uncertainty of the small axis drops by more than a third because of the lower sub-Earth latitude afforded in 2003 (-28°) compared to 2008 (+47°), and the triaxial ellipsoid diameters become 218x175x129 km with fitting uncertainties of 3x3x14 km. We have estimated the systematic uncertainty of our method to be 4.1, 2.7, and 3.8%, respectively, for the three diameters. These values were recently derived (Drummond et al., in prep) from a comparison of KOALA (Carry et al, Planetary and Space Science 66, 200-212) and our triaxial ellipsoid analysis of four asteroids. Quadratically adding this systematic error with the fitting error, the total uncertainty for Metis becomes 9x5x15 km. Concurrently, we find an EQJ2000 rotational pole at [RA; Dec]=[185° +19°] or in ecliptic coordinates, [λ ; β ]=[176° +20°] (ECJ2000).

  8. Tetrahedral tilting and ferroelectricity in Bi2AO5 (A=Si, Ge) from first principles calculations

    NASA Astrophysics Data System (ADS)

    Park, Janghee; Kim, Bog G.; Mori, Shigeo; Oguchi, Tamio

    2016-03-01

    The properties of a tetrahedron containing Bi2AO5 (A=Si, Ge) are examined using Ab initio calculations and symmetry mode analysis. Stabilization of the polar phase is observed in both compounds with a monoclinic Cc phase. In the monoclinic ground state, the tilting angle (ϕ1) of tetrahedron is 7.21° and 21.94° for the Si and Ge compound, respectively. The relationship between a primary order parameter and the tetrahedral tilting is identified and an analytical formula between them is proposed by analyzing the structure. The detailed layer-by-layer polarization calculations shows that the main polarization component originates from the tetrahedron tilting of the AO4 unit, and the analytical relationship between the primary order parameter and spontaneous polarization is also calculated. This B3LYP hybrid functional calculation provides a band gap of 4.44 eV and 4.18 eV for Bi2SiO5 and Bi2GeO5, respectively. The main difference between the two compounds is also analyzed based on the electronic structure and electron localization function analysis.

  9. THE FIRST CIRCUMSTELLAR DISK IMAGED IN SILHOUETTE AT VISIBLE WAVELENGTHS WITH ADAPTIVE OPTICS: MagAO IMAGING OF ORION 218-354

    SciTech Connect

    Follette, Katherine B.; Close, Laird M.; Males, Jared R.; Wu, Ya-Lin; Morzinski, Katie M.; Hinz, Philip; Rodigas, Timothy J.; Kopon, Derek; Puglisi, Alfio; Esposito, Simone; Riccardi, Armando; Pinna, Enrico; Xompero, Marco; Briguglio, Runa

    2013-09-20

    We present high-resolution adaptive optics (AO) corrected images of the silhouette disk Orion 218-354 taken with Magellan AO (MagAO) and its visible light camera, VisAO, in simultaneous differential imaging mode at Hα. This is the first image of a circumstellar disk seen in silhouette with AO and is among the first visible light AO results in the literature. We derive the disk extent, geometry, intensity, and extinction profiles and find, in contrast with previous work, that the disk is likely optically thin at Hα. Our data provide an estimate of the column density in primitive, ISM-like grains as a function of radius in the disk. We estimate that only ∼10% of the total submillimeter derived disk mass lies in primitive, unprocessed grains. We use our data, Monte Carlo radiative transfer modeling, and previous results from the literature to make the first self-consistent multiwavelength model of Orion 218-354. We find that we are able to reproduce the 1-1000 μm spectral energy distribution with a ∼2-540 AU disk of the size, geometry, small versus large grain proportion, and radial mass profile indicated by our data. This inner radius is a factor of ∼15 larger than the sublimation radius of the disk, suggesting that it is likely cleared in the very interior.

  10. Production and characterisation of AoSOX2 from Aspergillus oryzae, a novel flavin-dependent sulfhydryl oxidase with good pH and temperature stability.

    PubMed

    Faccio, Greta; Kruus, Kristiina; Buchert, Johanna; Saloheimo, Markku

    2011-05-01

    Sulfhydryl oxidases have found application in the improvement of both dairy and baking products due to their ability to oxidise thiol groups in small molecules and cysteine residues in proteins. A genome mining study of the available fungal genomes had previously been performed by our group in order to identify novel sulfhydryl oxidases suitable for industrial applications and a representative enzyme was produced, AoSOX1 from Aspergillus oryzae (Faccio et al. BMC Biochem 11:31, 2010). As a result of the study, a second gene coding for a potentially secreted sulfhydryl oxidase, AoSOX2, was identified in the genome of A. oryzae. The protein AoSOX2 was heterologously expressed in Trichoderma reesei and characterised with regard to both biochemical properties as well as preliminary structural analysis. AoSOX2 showed activity on dithiothreitol and glutathione, and to a lesser extent on D/L-cysteine and beta-mercaptoethanol. AoSOX2 was a homodimeric flavin-dependent protein of approximately 78 kDa (monomer 42412 Da) and its secondary structure presents alpha-helical elements. A. oryzae AoSOX2 showed a significant stability to pH and temperature. PMID:21327412

  11. Evaluation of a novel integrated bioreactor--AOS system for treating oil-containing restaurant wastewater on site in Hong Kong.

    PubMed

    Wang, L; Zhou, Q; Chua, H

    2005-01-01

    AOS system is an anaerobic digestion reactor (A-section, UASB or UBF), oxidation degradation reactor (O-section, aerobic biofilm reactor), and physical sedimentation tank (S-section) 3-in-1 integrated reactor. The compact bioreactor was applied to treat oil-containing restaurant's wastewater on site in Hong Kong. The treatment efficiency was observed at different HRT. Experimental results indicated that the AOS system for treating oil-containing restaurant wastewater on site was feasible when HRT at 0.6 days above. During the running period, the net sludge generation rate of the AOS system was only about 0.08-0.09 g g(-1)removed COD, and the utmost COD specific volumetric removal rate (SVRR) of the system reached 2.77 gL(-1) d(-1). The utmost specific biomass substrate utilization rate (SBSUR) of COD in O-section and A-section reached 1.22 d(-1) and 0.128 d(-1), respectively. In addition, the experiment results showed that the AOS system with a filter in UASB (that is UBF's AOS system) could bear much more great HLR comparing with UASB's AOS and was more efficient for treating oil-containing restaurant's wastewater on site. PMID:15663313

  12. A Survey of the High Order Multiplicity of Nearby Solar-type Binary Stars with Robo-AO

    NASA Astrophysics Data System (ADS)

    Riddle, Reed L.; Tokovinin, Andrei; Mason, Brian D.; Hartkopf, William I.; Roberts, Lewis C., Jr.; Baranec, Christoph; Law, Nicholas M.; Bui, Khanh; Burse, Mahesh P.; Das, H. K.; Dekany, Richard G.; Kulkarni, Shrinivas; Punnadi, Sujit; Ramaprakash, A. N.; Tendulkar, Shriharsh P.

    2015-01-01

    We conducted a survey of nearby binary systems composed of main sequence stars of spectral types F and G in order to improve our understanding of the hierarchical nature of multiple star systems. Using Robo-AO, the first robotic adaptive optics instrument, we collected high angular resolution images with deep and well-defined detection limits in the Sloan Digital Sky Survey i' band. A total of 695 components belonging to 595 systems were observed. We prioritized observations of faint secondary components with separations over 10'' to quantify the still poorly constrained frequency of their subsystems. Of the 214 secondaries observed, 39 contain such subsystems; 19 of those were discovered with Robo-AO. The selection-corrected frequency of secondary subsystems with periods from 103.5 to 105 days is 0.12 ± 0.03, the same as the frequency of such companions to the primary. Half of the secondary pairs belong to quadruple systems where the primary is also a close pair, showing that the presence of subsystems in both components of the outer binary is correlated. The relatively large abundance of 2+2 quadruple systems is a new finding, and will require more exploration of the formation mechanism of multiple star systems. We also targeted close binaries with periods less than 100 yr, searching for their distant tertiary components, and discovered 17 certain and 2 potential new triples. In a subsample of 241 close binaries, 71 have additional outer companions. The overall frequency of tertiary components is not enhanced, compared to all (non-binary) targets, but in the range of outer periods from 106 to 107.5 days (separations on the order of 500 AU), the frequency of tertiary components is 0.16 ± 0.03, exceeding the frequency of similar systems among all targets (0.09) by almost a factor of two. Measurements of binary stars with Robo-AO allowed us to compute first orbits for 9 pairs and to improve orbits of another 11 pairs.

  13. A SURVEY OF THE HIGH ORDER MULTIPLICITY OF NEARBY SOLAR-TYPE BINARY STARS WITH Robo-AO

    SciTech Connect

    Riddle, Reed L.; Bui, Khanh; Dekany, Richard G.; Kulkarni, Shrinivas; Tendulkar, Shriharsh P.; Tokovinin, Andrei; Mason, Brian D.; Hartkopf, William I.; Roberts, Lewis C. Jr.; Baranec, Christoph; Law, Nicholas M.; Burse, Mahesh P.; Das, H. K.; Punnadi, Sujit; Ramaprakash, A. N.

    2015-01-20

    We conducted a survey of nearby binary systems composed of main sequence stars of spectral types F and G in order to improve our understanding of the hierarchical nature of multiple star systems. Using Robo-AO, the first robotic adaptive optics instrument, we collected high angular resolution images with deep and well-defined detection limits in the Sloan Digital Sky Survey i' band. A total of 695 components belonging to 595 systems were observed. We prioritized observations of faint secondary components with separations over 10'' to quantify the still poorly constrained frequency of their subsystems. Of the 214 secondaries observed, 39 contain such subsystems; 19 of those were discovered with Robo-AO. The selection-corrected frequency of secondary subsystems with periods from 10{sup 3.5} to 10{sup 5} days is 0.12 ± 0.03, the same as the frequency of such companions to the primary. Half of the secondary pairs belong to quadruple systems where the primary is also a close pair, showing that the presence of subsystems in both components of the outer binary is correlated. The relatively large abundance of 2+2 quadruple systems is a new finding, and will require more exploration of the formation mechanism of multiple star systems. We also targeted close binaries with periods less than 100 yr, searching for their distant tertiary components, and discovered 17 certain and 2 potential new triples. In a subsample of 241 close binaries, 71 have additional outer companions. The overall frequency of tertiary components is not enhanced, compared to all (non-binary) targets, but in the range of outer periods from 10{sup 6} to 10{sup 7.5} days (separations on the order of 500 AU), the frequency of tertiary components is 0.16 ± 0.03, exceeding the frequency of similar systems among all targets (0.09) by almost a factor of two. Measurements of binary stars with Robo-AO allowed us to compute first orbits for 9 pairs and to improve orbits of another 11 pairs.

  14. A1Ao-ATP synthase of Methanobrevibacter ruminantium couples sodium ions for ATP synthesis under physiological conditions.

    PubMed

    McMillan, Duncan G G; Ferguson, Scott A; Dey, Debjit; Schröder, Katja; Aung, Htin Lin; Carbone, Vincenzo; Attwood, Graeme T; Ronimus, Ron S; Meier, Thomas; Janssen, Peter H; Cook, Gregory M

    2011-11-18

    An unresolved question in the bioenergetics of methanogenic archaea is how the generation of proton-motive and sodium-motive forces during methane production is used to synthesize ATP by the membrane-bound A(1)A(o)-ATP synthase, with both proton- and sodium-coupled enzymes being reported in methanogens. To address this question, we investigated the biochemical characteristics of the A(1)A(o)-ATP synthase (MbbrA(1)A(o)) of Methanobrevibacter ruminantium M1, a predominant methanogen in the rumen. Growth of M. ruminantium M1 was inhibited by protonophores and sodium ionophores, demonstrating that both ion gradients were essential for growth. To study the role of these ions in ATP synthesis, the ahaHIKECFABD operon encoding the MbbrA(1)A(o) was expressed in Escherichia coli strain DK8 (?atp) and purified yielding a 9-subunit protein with an SDS-stable c oligomer. Analysis of the c subunit amino acid sequence revealed that it consisted of four transmembrane helices, and each hairpin displayed a complete Na(+)-binding signature made up of identical amino acid residues. The purified MbbrA(1)A(o) was stimulated by sodium ions, and Na(+) provided pH-dependent protection against inhibition by dicyclohexylcarbodiimide but not tributyltin chloride. ATP synthesis in inverted membrane vesicles lacking sodium ions was driven by a membrane potential that was sensitive to cyanide m-chlorophenylhydrazone but not to monensin. ATP synthesis could not be driven by a chemical gradient of sodium ions unless a membrane potential was imposed. ATP synthesis under these conditions was sensitive to monensin but not cyanide m-chlorophenylhydrazone. These data suggest that the M. ruminantium M1 A(1)A(o)-ATP synthase exhibits all the properties of a sodium-coupled enzyme, but it is also able to use protons to drive ATP synthesis under conditions that favor proton coupling, such as low pH and low levels of sodium ions. PMID:21953465

  15. ROSAT guest investigator program (AO-1). On a search for coronal x ray emissions from white dwarfs

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.

    1992-01-01

    We have suggested that cool magnetic white dwarfs may be sources of X-ray coronal emission and proposed several prominent candidates for this emission. One of these candidates (EG 250) was approved for the C-category observation by the National and International Committee and was observed by ROSAT on April 17, 1991. Unfortunately, the granted exposure time (1071 s) was much shorter than that which was required by theoretical predictions to observe coronal X-ray emission from this object. The tape containing the data was send to us in November 1991. Since then we have analyzed the data visiting the ROSAT Science Center at NASA Goddard Space Flight Center. The analysis of the data taken during this short observation show, as expected, no X-rays. It is our hope that EG 250 will be observed again during the AO-2 phase of pointed observations, as 10,000 s of observing time was granted to V. Trimble for the C-category observation of this star. We have a close contact with Dr. Trimble regarding this matter. Because our all targets (GD 90, KUV 2316-123 and GD 356) proposed for the observation during the AO-2 phase of pointed observations have been approved by the National and International Committee, we have installed the required software at NASA/MSFC to be able to carry out the data analysis in Huntsville. Two of our targets have already been observed (KUV 2316-123 was observed on Dec. 3, 1991 with 10,000 s of the exposure time, and GD 356 was observed on Jan 4, 1992 with 5,000 s of the exposure time). We just received the data and will begin the analysis soon. The results of our analysis will be reported to the scientific community by publishing papers in the Astrophysical Journal Letters. Our intention is to submit a paper when the analysis of the data taken during AO2 is completed. The data taken during the observation of EG 250 will be a part of this paper.

  16. Insights into Ubiquitination from the Unique Clamp-like Binding of the RING E3 AO7 to the E2 UbcH5B.

    PubMed

    Li, Shengjian; Liang, Yu-He; Mariano, Jennifer; Metzger, Meredith B; Stringer, Daniel K; Hristova, Ventzislava A; Li, Jess; Randazzo, Paul A; Tsai, Yien Che; Ji, Xinhua; Weissman, Allan M

    2015-12-18

    RING proteins constitute the largest class of E3 ubiquitin ligases. Unlike most RINGs, AO7 (RNF25) binds the E2 ubiquitin-conjugating enzyme, UbcH5B (UBE2D2), with strikingly high affinity. We have defined, by co-crystallization, the distinctive means by which AO7 binds UbcH5B. AO7 contains a structurally unique UbcH5B binding region (U5BR) that is connected by an 11-amino acid linker to its RING domain, forming a clamp surrounding the E2. The U5BR interacts extensively with a region of UbcH5B that is distinct from both the active site and the RING-interacting region, referred to as the backside of the E2. An apparent paradox is that the high-affinity binding of the AO7 clamp to UbcH5B, which is dependent on the U5BR, decreases the rate of ubiquitination. We establish that this is a consequence of blocking the stimulatory, non-covalent, binding of ubiquitin to the backside of UbcH5B. Interestingly, when non-covalent backside ubiquitin binding cannot occur, the AO7 clamp now enhances the rate of ubiquitination. The high-affinity binding of the AO7 clamp to UbcH5B has also allowed for the co-crystallization of previously described and functionally important RING mutants at the RING-E2 interface. We show that mutations having marked effects on function only minimally affect the intermolecular interactions between the AO7 RING and UbcH5B, establishing a high degree of complexity in activation through the RING-E2 interface. PMID:26475854

  17. AO-OCT for in vivo mouse retinal imaging: Application of adaptive lens in wavefornt sensorless aberration correction

    NASA Astrophysics Data System (ADS)

    Bonora, Stefano; Jian, Yifan; Pugh, Edward N.; Sarunic, Marinko V.; Zawadzki, Robert J.

    2014-03-01

    We demonstrate Adaptive optics - Optical Coherence Tomography (OCT) with modal sensorless Adaptive Optics correction with the use of novel Adaptive Lens (AL) applied for in-vivo imaging of mouse retinas. The AL can generate low order aberrations: defocus, astigmatism, coma and spherical aberration that were used in an adaptive search algorithm. Accelerated processing of the OCT data with a Graphic Processing Unit (GPU) permitted real time extraction of image projection total intensity for arbitrarily selected retinal depth plane to be optimized. Wavefront sensorless control is a viable option for imaging biological structures for which AOOCT cannot establish a reliable wavefront that could be corrected by wavefront corrector. Image quality improvements offered by adaptive lens with sensorless AO-OCT was evaluated on in vitro samples followed by mouse retina data acquired in vivo.

  18. Open Reduction for AO/OTA 81-B3 (Hawkins 3) Talar Neck Fractures: The Natural Delivery Method.

    PubMed

    Simpson, R B; Auston, Darryl A

    2016-03-01

    Fractures of the talar neck with subtalar and tibiotalar joint dislocation (AO/OTA 81-B3) represent a treatment challenge for the orthopedic surgeon. The magnitude of deformity and complexity of the pathoanatomy adds to concerns for soft tissue embarrassment to convey an urgency of surgical intervention. Previous studies have described the several techniques for talar reduction, including medial malleolar osteotomy, posterior Schanz pin manipulation, or posteromedial incision to facilitate relocation at the time of definitive open treatment. We describe a simple technique for stepwise surgical intervention using adjuncts to reduction on the surgical field that facilitate an atraumatic relocation of the displaced body fragment through a standard lateral incision, simplifying fixation of the residual talar neck fracture. A reasonable metaphor for the technique is its similarity to reducing an obstetric shoulder dystocia in the delivery of a newborn infant. PMID:26709817

  19. Theoretical studies of the osmium based perovskites AOsO3 (A=Ca, Sr and Ba)

    NASA Astrophysics Data System (ADS)

    Ali, Zahid; Sattar, Abdul; Asadabadi, S. Jalali; Ahmad, Iftikhar

    2015-11-01

    Osmium based perovskites AOsO3 (A=Ca, Sr and Ba) have been studied theoretically using density functional theory approach. These studies show that CaOsO3 and SrOsO3 are orthorhombic and BaOsO3 is cubic and are consistent with the experiments. The electronic band structures demonstrate that these compounds are metals. The magnetic studies verify the experimental observations at low temperature, where the spin effects are canceled by the orbitals. The stable magnetic phase optimizations and magnetic susceptibilities calculations by the post-DFT treatment confirm that CaOsO3 and SrOsO3 are weak ferromagnetic whereas BaOsO3 is a paramagnetic material. The directional magnetic study shows that these compounds are magnetically anisotropic, and reveals that the easy magnetization axis is [001] direction.

  20. Dealing with the forecast of the optical turbulence as a tool to support astronomy assisted by AO facilities

    NASA Astrophysics Data System (ADS)

    Masciadri, Elena; Lascaux, Franck; Fini, Luca

    2015-04-01

    In the context of the research activities related to the forecast of the optical turbulence and the atmospherical parameters being relevant for ground-based astronomy we focus here our attention on two specific topics: 1. pros and cons of different solutions to supply wind speed and direction stratification on the whole atmosphere all along a night to support AO facilities; 2. the necessity of instrumentation for optical turbulence monitoring (vertical profiles on the whole atmosphere) to be used operationally. In the last two decades the development and the use of different vertical profilers covering the whole atmosphere or part of it in application to the astronomy took place. Several instruments based on different principles (with associated pros and cons) have been applied in different contexts in astronomy with a main use in the site characterization and site selection. Time changed and the necessity of the astronomy supported by AO facilities is much more demanding with a diversification of applications. Recently, motivated by a precise necessity related to the identification of an absolute reference to carry out studies on optical turbulence forecasts (MOSE project), we carried out a verification of the reliability of a few instruments that lead us to put in evidence some limitations for a few of them. At the same time such a detailed analysis permitted us to clarify the nature of some astroclimatic parameters. The main conclusion at which we arrived is two-fold. From one side we could trace a list of warnings related to different uses of such instruments. On the other side we could identify open problems that indicate that there is still space for research in the field of turbulence monitoring in application to the astronomy. Some suggestions are proposed.

  1. [Animal experiment study of tensile strength of hydroxylapatite-coated AO/ASIF Schanz screws for external fixators].

    PubMed

    Dávid, A; Pommer, A; Eitenmüller, J; Muhr, G; Hahn, M P

    1994-08-01

    The removal torque and the loosening and infection rates of AO/ASIF 4.5 mm Schanz screws (MS) have been compared with those of hydroxyapatite-coated (HA) and hydroxyapatite/silver phosphate-coated (HA/P) AO/ASIF Schanz screws in vivo. In sheep, the left tibia was fixed after a midshaft osteotomy by means of unilateral fixator with 6 Schanz screws in an antero-lateral position. The osteotomy gap was filled with bone wax to avoid bony overgrowth. After operation, the animals were allowed to walk around immediately. The loosening rate was 2.8% at the site of the two HA-coated screws and 36% at the site of the metal screws. The removal torque after 2, 4 and 6 months was 6.2 +/- 2.8 MPa for HA/P, 4.7 +/- 2.7 MPa for HA screws and 1.2 +/- 1.1 MPa for metal screws. Histological and fluoroscopic evaluation revealed intimate bone-HA contact at the cortex near to the fixator, whereas at the site of the metal screws a fibrous tissue layer was constantly found. Only in the cortex opposite to the external fixator a direct bone-metal interface was observed. Fluoroscopic analyses confirmed new bone formation next to the HA surface especially in the cortex adjacent to the fixator, whereas such phenomena were not detected adjacent to the surface of the metal screws. Furthermore, bony resorption around the metal screws (21%) was significantly greater than around the two coated screws (2%). These experimental data suggest that pin loosening can be reduced in external fixators by coating the screws with hydroxyapatite, especially if a long-term fixation is indicated. PMID:7973737

  2. Characterization of OCam and CCD220: the fastest and most sensitive camera to date for AO wavefront sensing

    NASA Astrophysics Data System (ADS)

    Feautrier, Philippe; Gach, Jean-Luc; Balard, Philippe; Guillaume, Christian; Downing, Mark; Hubin, Norbert; Stadler, Eric; Magnard, Yves; Skegg, Michael; Robbins, Mark; Denney, Sandy; Suske, Wolfgang; Jorden, Paul; Wheeler, Patrick; Pool, Peter; Bell, Ray; Burt, David; Davies, Ian; Reyes, Javier; Meyer, Manfred; Baade, Dietrich; Kasper, Markus; Arsenault, Robin; Fusco, Thierry; Diaz-Garcia, José Javier

    2010-07-01

    For the first time, sub-electron read noise has been achieved with a camera suitable for astronomical wavefront-sensing (WFS) applications. The OCam system has demonstrated this performance at 1300 Hz frame rate and with 240×240-pixel frame rate. ESO and JRA2 OPTICON2 have jointly funded e2v technologies to develop a custom CCD for Adaptive Optics (AO) wavefront sensing applications. The device, called CCD220, is a compact Peltier-cooled 240×240 pixel frame-transfer 8-output back-illuminated sensor using the EMCCD technology. This paper demonstrates sub-electron read noise at frame rates from 25 Hz to 1300 Hz and dark current lower than 0.01 e-/pixel/frame. It reports on the comprehensive, quantitative performance characterization of OCam and the CCD220 such as readout noise, dark current, multiplication gain, quantum efficiency, charge transfer efficiency... OCam includes a low noise preamplifier stage, a digital board to generate the clocks and a microcontroller. The data acquisition system includes a user friendly timer file editor to generate any type of clocking scheme. A second version of OCam, called OCam2, was designed offering enhanced performances, a completely sealed camera package and an additional Peltier stage to facilitate operation on a telescope or environmentally rugged applications. OCam2 offers two types of built-in data link to the Real Time Computer: the CameraLink industry standard interface and various fiber link options like the sFPDP interface. OCam2 includes also a modified mechanical design to ease the integration of microlens arrays for use of this camera in all types of wavefront sensing AO system. The front cover of OCam2 can be customized to include a microlens exchange mechanism.

  3. A useful surgical strategy for proximal tibial fractures (AO/OTA type 41-C) with diaphyseal involvement

    PubMed Central

    Wu, Dankai; Reng, Guangkai; Shrivastava, Ankit; Yu, Ying; Zhang, Yueyang; Peng, Chuangang

    2015-01-01

    Relatively few studies have addressed surgical strategy for complex proximal tibial fractures by now. The purpose of this study was to assess the results of a single lateral locking plate using minimally invasive plate osteosynthesis (MIPO) for proximal tibia fractures (AO/OTA type 41-C) with diaphyseal involvement. From Jun 2009 to Jun 2014, 20 patients (fifteen women and five men, mean age 35.8 years) were managed for proximal tibial fractures which extend into the diaphyseal region of the bone, including three 41-C1, eleven 41-C2, and six 41-C3. Twelve patients were open fractures. A single lateral locking plate characterized by percutaneous technology was used with or without additional lag screws. Mobilization was started immediately after the procedure, and non-weight-bearing was maintained for at least 6 weeks, then progressively weight bearing depends on both clinical and x-ray findings. Primary union was achieved by 16 of the 20 study subjects. Early bone grafting was performed in 4 cases with a massive initial bone defect and staged bone grafting was used in one to treat nonunion. The mean articular step off was 1.0 mm (range, 0-3 mm). No patient had misalignment greater than 10°. Acceptable range of knee motion of ≥120° was achieved in sixteen, and the mean knee Hass score was 87.4 at final follow-up visits. The complications included superficial infection in one patient. In conclusion, the surgical strategy can provide favorable results in the treatment of proximal tibial fractures (AO/OTA type 41-C) with diaphyseal involvement. PMID:26550282

  4. The First AO Classification System for Fractures of the Craniomaxillofacial Skeleton: Rationale, Methodological Background, Developmental Process, and Objectives

    PubMed Central

    Audigé, Laurent; Cornelius, Carl-Peter; Ieva, Antonio Di; Prein, Joachim

    2014-01-01

    Validated trauma classification systems are the sole means to provide the basis for reliable documentation and evaluation of patient care, which will open the gateway to evidence-based procedures and healthcare in the coming years. With the support of AO Investigation and Documentation, a classification group was established to develop and evaluate a comprehensive classification system for craniomaxillofacial (CMF) fractures. Blueprints for fracture classification in the major constituents of the human skull were drafted and then evaluated by a multispecialty group of experienced CMF surgeons and a radiologist in a structured process during iterative agreement sessions. At each session, surgeons independently classified the radiological imaging of up to 150 consecutive cases with CMF fractures. During subsequent review meetings, all discrepancies in the classification outcome were critically appraised for clarification and improvement until consensus was reached. The resulting CMF classification system is structured in a hierarchical fashion with three levels of increasing complexity. The most elementary level 1 simply distinguishes four fracture locations within the skull: mandible (code 91), midface (code 92), skull base (code 93), and cranial vault (code 94). Levels 2 and 3 focus on further defining the fracture locations and for fracture morphology, achieving an almost individual mapping of the fracture pattern. This introductory article describes the rationale for the comprehensive AO CMF classification system, discusses the methodological framework, and provides insight into the experiences and interactions during the evaluation process within the core groups. The details of this system in terms of anatomy and levels are presented in a series of focused tutorials illustrated with case examples in this special issue of the Journal. PMID:25489387

  5. Swimming with ShARCS: comparison of on-sky sensitivity with model predictions for ShaneAO on the Lick Observatory 3-meter telescope

    NASA Astrophysics Data System (ADS)

    Srinath, Srikar; McGurk, Rosalie; Rockosi, Constance; Kupke, Renate; Gavel, Donald; Cabak, Gerald; Cowley, David; Peck, Michael; Ratliff, Christopher; Gates, Elinor; Dillon, Daren; Norton, Andrew; Reining, Marc

    2014-08-01

    The Lick Observatory's Shane 3-meter telescope has been upgraded with a new infrared instrument (ShARCS - Shane Adaptive optics infraRed Camera and Spectrograph) and dual-deformable mirror adaptive optics (AO) system (ShaneAO). We present first-light measurements of imaging sensitivity in the Ks band. We compare mea- sured results to predicted signal-to-noise ratio and magnitude limits from modeling the emissivity and throughput of ShaneAO and ShARCS. The model was validated by comparing its results to the Keck telescope adaptive optics system model and then by estimating the sky background and limiting magnitudes for IRCAL, the pre- vious infra-red detector on the Shane telescope, and comparing to measured, published results. We predict that the ShaneAO system will measure lower sky backgrounds and achieve 20% higher throughput across the JHK bands despite having more optical surfaces than the current system. It will enable imaging of fainter objects (by 1-2 magnitudes) and will be faster to reach a fiducial signal-to-noise ratio by a factor of 10-13. We highlight the improvements in performance over the previous AO system and its camera, IRCAL.

  6. Promoter isolation and characterization of GhAO-like1, a Gossypium hirsutum gene similar to multicopper oxidases that is highly expressed in reproductive organs.

    PubMed

    Lambret-Frotté, Julia; Artico, Sinara; Muniz Nardeli, Sarah; Fonseca, Fernando; Brilhante Oliveira-Neto, Osmundo; Grossi-de-Sá, Maria Fatima; Alves-Ferreira, Marcio

    2016-01-01

    Cotton is one of the most economically important cultivated crops. It is the major source of natural fiber for the textile industry and an important target for genetic modification for both biotic stress and herbicide tolerance. Therefore, the characterization of genes and regulatory regions that might be useful for genetic transformation is indispensable. The isolation and characterization of new regulatory regions is of great importance to drive transgene expression in genetically modified crops. One of the major drawbacks in cotton production is pest damage; therefore, the most promising, cost-effective, and sustainable method for pest control is the development of genetically resistant cotton lines. Considering this scenario, our group isolated and characterized the promoter region of a MCO (multicopper oxidase) from Gossypium hirsutum, named GhAO-like1 (ascorbate oxidase-like1). The quantitative expression, together with the in vivo characterization of the promoter region reveals that GhAO-like1 has a flower- and fruit-specific expression pattern. The GUS activity is mainly observed in stamens, as expected considering that the GhAO-like1 regulatory sequence is enriched in cis elements, which have been characterized as a target of reproductive tissue specific transcription factors. Both histological and quantitative analyses in Arabidopsis thaliana have confirmed flower (mainly in stamens) and fruit expression of GhAO-like1. In the present paper, we isolated and characterized both in silico and in vivo the promoter region of the GhAO-like1 gene. The regulatory region of GhAO-like1 might be useful to confer tissue-specific expression in genetically modified plants. PMID:26692462

  7. Loblolly pine abietadienol/abietadienal oxidase PtAO (CYP720B1) is a multifunctional, multisubstrate cytochrome P450 monooxygenase

    PubMed Central

    Ro, Dae-Kyun; Arimura, Gen-Ichiro; Lau, Stephen Y. W.; Piers, Edward; Bohlmann, Jörg

    2005-01-01

    Cytochrome P450 monooxygenases (P450s) are important enzymes for generating some of the enormous structural diversity of plant terpenoid secondary metabolites. In conifers, P450s are involved in the formation of a suite of diterpene resin acids (DRAs). Despite their important role in constitutive and induced oleoresin defense, a P450 gene of DRA formation has not yet been identified. By using phylogenetic cluster analysis of P450-like ESTs from loblolly pine (Pinus taeda), functional cDNA screening in yeast (Saccharomyces cerevisiae), and in vitro enzyme characterization, we cloned and identified a multifunctional and multisubstrate cytochrome P450 enzyme, CYP720B1 [abietadienol/abietadienal oxidase (PtAO)]. PtAO catalyzes an array of consecutive oxidation steps with several different diterpenol and diterpenal intermediates in loblolly pine DRA biosynthesis. Recombinant PtAO oxidized the respective carbon 18 of abietadienol, abietadienal, levopimaradienol, isopimara-7,15-dienol, isopimara-7,15-dienal, dehydroabietadienol, and dehydroabietadienal with apparent Michaelis–Menten (Km) values of 0.5–5.3 ?M. PtAO expressed in yeast also catalyzed in vivo oxidation of abietadiene to abietic acid, but with activity much lower than with abietadienol or abietadienal. Consistent with a role of DRAs in conifer defense, PtAO transcript levels increased upon simulated insect attack using methyl jasmonate treatment of loblolly pine. The multisubstrate, multifunctional P450 diterpene oxidase PtAO, in concert with expression of a family of single-product and multiproduct diterpene synthases, allows for formation of a diverse suite of DRA defense metabolites in long-lived conifers. PMID:15911762

  8. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10 EL-1994-00162 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray E10 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in the Orbiter Processing Facility during removal of the LDEF from the Orbiter's payload bay. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal covers surface appears to have changed from specular to opaque with numerous black dots of various sizes that appear to be impact craters. Many of the craters appear to have a black center encircled by a brown halo. Other circular discolorations also appear on the cover surface. The darker discolorations probably result from an impact that penetrates the 5 mil TEFLON® film and allows atomic oxygen to oxidize and/or erode the vapor deposited silver layer beneath. The cover is taut and the locations of Velcro attach pads are prominent. The pinkish green tint on the thermal cover is caused by the lighting and reflections from the surroundings.The ground strap appears to be intact with no visible damage but appears to be a deeper copper color.

  9. SRT Evaluation of AIRS Version-6.02 and Version-6.02 AIRS Only (6.02 AO) Products

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Iredell, Lena; Molnar, Gyula; Blaisdell, John

    2012-01-01

    Version-6 contains a number of significant improvements over Version-5. This report compares Version-6 products resulting from the advances listed below to those from Version-5. 1. Improved methodology to determine skin temperature (T(sub s)) and spectral emissivity (Epsilon(sub v)). 2. Use of Neural-net start-up state. 3. Improvements which decrease the spurious negative Version-5 trend in tropospheric temperatures. 4. Improved QC methodology. Version-6 uses separate QC thresholds optimized for Data Assimilation (QC=0) and Climate applications (QC=0,1) respectively. 5. Channel-by-channel clear-column radiances R-hat(sub tau) QC flags. 6. Improved cloud parameter retrieval algorithm. 7. Improved OLR RTA. Our evaluation compared V6.02 and V6.02 AIRS Only (V6.02 AO) Quality Controlled products with those of Version-5.0. In particular we evaluated surface skin temperature T(sub s), surface spectral emissivity Epsilon(sub v), temperature profile T(p), water vapor profile q(p), OLR, OLR(sub CLR), effective cloud fraction alpha-Epsilon, and cloud cleared radiances R-hat(sub tau) . We conducted two types of evaluations. The first compared results on 7 focus days to collocated ECMWF truth. The seven focus days are: September 6, 2002; January 25, 2003; September 29, 2004; August 5, 2005; February 24, 2007; August 10, 2007; and May 30, 2010. In these evaluations, we show results for T(sub s), Epsilon(sub v), T(p), and q(p) in terms of yields, and RMS differences and biases with regard to ECMWF. We also show yield trends as well as bias trends of these quantities relative to ECMWF truth. We also show yields and accuracy of channel by channel QC d values of R-hat(sub tau) for V6.02 and V6.02 AO. Version-5 did not contain channel by channel QC d values of R-hat(sub tau). In the second type of evaluation, we compared V6.03 monthly mean Level-3 products to those of Version-5.0, for four different months: January, April, July, and October; in 3 different years 2003, 2007, and 2011. In particular, we compared V6.03 and V5.0 trends of T(p), q(p), alpha-Epsilon, OLR, and OLR(sub CLR) computed based on results for these 12 time periods

  10. AO-assisted observations of G61.48+0.09. Massive star formation at high resolution

    NASA Astrophysics Data System (ADS)

    Puga, E.; Alvarez, C.; Feldt, M.; Henning, Th.; Wolf, S.

    2004-10-01

    The characterisation of the stellar populations of ultra-compact HII (UCHII{}) regions is one of the key means of understanding the formation and evolution of massive stars. Adaptive Optics (AO) assisted near-infrared (NIR) observations provide sufficient resolution and sensitivity to detect such populations at moderate extinction values. We present NIR high-resolution observations of G61.48+0.09, a morphologically complex UCHII region with two components, whose accessible stellar content in the NIR has been widely studied before. A polarimetric map in the K' band, as well as H2(1-0) S(1) and Br? narrow-band images of the region have been obtained with the AO system ALFA at the Calar Alto Observatory's 3.5 m telescope. We also present high-resolution imaging of the same region in the L' band with NAOS+CONICA at the VLT (UT4). The study of the nebular scattered light points to an internal-illumination model for the eastern component (B2). This model is confirmed by the detection of a point-like source in the L'-band data. In the western component (B1) the observed NIR colours of star 82 are consistent with spectral types BIa or early OV, while star 83 is reproduced by a B0V. Therefore, we identify these objects as the main detected ionising sources. However, in terms of illumination, our polarimetric map indicates that these two stars are not the dominating illuminators of the reflection nebula. Illumination from multiple sources (possibly still undetected) seems to influence the polarisation pattern for this component. Geometric considerations in the calculation of the energetics of this region, combined with the knowledge of the detected stellar content, also points to the presence of other ionising sources. Our study reinforces the hypothesis that there is a champagne flow towards the south-west part of the region. Visiting Astronomer, German-Spanish Astronomical Centre, Calar Alto, operated by the Max-Planck-Institute for Astronomy, Heidelberg, jointly with the Spanish National Commission for Astronomy. Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Programme 71.C-0143(A).

  11. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05 EL-1994-00311 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D05 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a brown stain. Outlines of experiment tray clamp blocks are clearly visible on the upper and lower tray flanges. The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal cover appears specular and intact with no apparent damage. A vertical strip of discoloration, approximately six inches wide and with a grain pattern, extends from top to bottom along the left side of the thermal cover. The cover appears less taut than in the flight photograph and locations of the Velcro attach pads are not as prominent. The ground strap appears to be in place with no visible damage, however, the color appears darked than in the prelaunch photograph.

  12. Rise of The Machines: First Year Operations of The Robo-AO Visible-Light Laser-Adaptive-Optics Instrument

    NASA Astrophysics Data System (ADS)

    Baranec, C.; Riddle, R.; Law, N.; Ramaprakash, A. N.; Tendulkar, S.; Hogstrom, K.; Bui, K.; Burse, M.; Chordia, P.; Das, H.; Dekany, R.

    2013-09-01

    Robo-AO is the first autonomous laser adaptive optics system and science instrument operating on sky. With minimal human oversight, the system robotically executes large scale surveys, monitors long-term astrophysical dynamics and characterizes newly discovered transients, all at the visible diffraction limit. The average target-to-target operational overhead, including slew time, is a mere 86 s, enabling up to ~200 observations per night. The first of many envisioned systems went live in June 2012, and has since finished 51 nights of science observing at the Palomar Observatory 60-inch (1.5 m) telescope, with over 5,600 robotic observations executed as of March 2013. The system will be augmented in late 2013 with a low-noise wide field infrared camera, which will double as a tip-tilt sensor, to widen the spectral bandwidth of observations, increase available sky coverage as well as enable deeper visible imaging using adaptive-optics sharpened infrared tip-tilt guide sources.

  13. LDEF (Postflight), AO133 : Effect of Space Environment on Space-Based Radar Phased-Array Antenna, Tr

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO133 : Effect of Space Environment on Space-Based Radar Phased-Array Antenna, Tray H07 The post landing photograph was taken from the Orbiter's cargo bay access hatch during post landing operations to prepare the Orbiter for the ferry flight from the Dryden Flight Research Center to the Kennedy Space Center. The Space-Based Radar (SBR) Phased-Array Antenna occupies a six (6) inch deep LDEF end corner tray located on the space end of the LDEF. A light tan discoloration can be seen on the left and lower flanges of the experiment tray and a darker stain has discolored the originally white paint dots on the experiment tray clamp blocks. Dark brown stains on the LDEF structure are vis- ible in areas adjacent to the edge of thermal end panels that were designed to facilitate venting of the LDEF interior. The SBR Phased-Array Antenna experiment, consisting of an active part in the left half of the tray and a passive part located in the right half of the experiment tray, appears to be intact with no apparent physical damage. The black thermal coating on the passive part of the experiment appears unchanged while the black thermal coating on the active part of the experiment appears dark gray. The passive experiment Kapton specimen surfaces appear to have changed from specular to diffuse after exposure to the space environment.

  14. LDEF (Flight), AO133 : Effect of Space Environment on Space-Based Radar Phased-Array Antenna, Tray H

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO133 : Effect of Space Environment on Space-Based Radar Phased-Array Antenna, Tray H07 The flight photograph was taken from the Orbiter aft flight deck during the LDEF retrieval. The Space-Based Radar (SBR) Phased-Array Antenna occupies a six (6) inch deep LDEF end corner tray located on the space end of the LDEF. A shadow cast by the Orbiter covers most of the right half of the tray containing the active part of the experiment. Even in the shadow, a light tan discoloration can be seen on the left and lower flanges of the experiment tray and a darker stain has discolored the originally white paint dots on the experiment tray clamp blocks. Dark brown stains on the LDEF structure are visible in areas adjacent to the edge of thermal end panels designed to facilitate venting of the LDEF interior. The SBR Phased-Array Antenna experiment, consisting of an active part in the left half of the tray and a passive part located in the right half of the experiment tray, appears to be intact with no apparent physical damage. The black thermal coating on the passive part of the experiment appears unchanged while the black thermal coating on the active part of the experiment appears a dark gray. The passive experiment Kapton specimen surfaces appear to have changed from specular to diffuse when exposed to the space environment.

  15. [Clinical results of primary intramedullary osteosynthesis with the unreamed AO/ASIF tibial intramedullary nail of open tibial shaft fractures].

    PubMed

    Müller, C A; Dietrich, M; Morakis, P; Pfister, U

    1998-11-01

    From 04/91 to 06/96 sixty-nine open fractures of the tibia were primarily treated on the day of the accident with unreamed nailing (UTN, Synthese). The distributions of fracture type according to the AO classification and of soft tissue injury according to Gustilo were as follows: fracture type: A: 28%, B: 52%, C: 20%; soft tissue injury: I: 30%, II: 28%, IIIA: 12%, IIIB: 12%, IIIC: 6%. Of the 65 fractures assessed 46 (71%) healed within 18 weeks without secondary intervention. There was delayed healing in three fractures requiring secondary conversion to reamed nailing. Eight fractures (12%) developed pseudarthrosis of which five (8%) healed uneventfully. Deep infections was manifest in four fractures (6%). Three of these infections developed after secondary intervention to treat pseudarthrosis. Seven of the eight pseudarthroses and three of the four infections healed eventually. Revision procedures were necessary in 11 patients (17%) to deal with disturbed fracture healing or infection (10 reamed nailing procedures, three cancellous bone grafts, and one of each of the following: sequestrectomy, fibular osteotomy, plate fixation, external fixator, monorail procedure). The results show that the same good infection rates were achieved for the UTN as for the external fixator. The advantages of the UTN are, however, a lesser need for secondary intervention and greater patient comfort. Therefore, we find the UTN to be a good alternative to the external fixator in the treatment of open fractures with severe soft tissue damage. PMID:9865165

  16. A spectroscopic search for colliding stellar winds in O-type close binary systems. I - AO Cassiopeiae

    NASA Technical Reports Server (NTRS)

    Gies, Douglas R.; Wiggs, Michael S.

    1991-01-01

    AO Cas, a short-period, double-lined spectroscopic binary, is studied as part of a search for spectroscopic evidence of colliding stellar winds in binary systems of O-type stars. High S/N ratio spectra of the H-alpha and He I 6678-A line profiles are presented, and their orbital-phase-related variations are examined in order to derive the location and motions of high-density circumstellar gas in the system. These profile variations are compared with those observed in the UV stellar wind lines in IUE archival spectra. IUE spectra are also used to derive a system mass ratio by constructing cross-correlation functions of a single-lined phase spectrum with each of the other spectra. The resulting mass ratio is consistent with the rotational line broadening of the primary star, if the primary is rotating synchronously with the binary system. The best-fit models were found to have an inclination of 61.1 deg + or - 3.0 deg and have a primary which is close to filling its critical Roche lobe.

  17. Structural analysis and molybdenum-dependent expression of the pAO1-encoded nicotine dehydrogenase genes of Arthrobacter nicotinovorans.

    PubMed

    Grether-Beck, S; Igloi, G L; Pust, S; Schilz, E; Decker, K; Brandsch, R

    1994-09-01

    The genes of nicotine dehydrogenase (NDH) were identified, cloned and sequenced from the catabolic plasmid pAO1 of Arthrobacter nicotinovorans. In immediate proximity to this gene cluster is the beginning of the 6-hydroxy-L-niotine oxidase (6-HLNO) gene. NDH is composed of three subunits (A, B and C) of M(r) 30,011, 14,924 and 87,677. It belongs to a family of bacterial hydroxylases with a similar subunit structure; they have molybdopterin dinucleotide, FAD and Fe-S clusters as cofactors. Here the first complete primary structure of a bacterial hydroxylase is provided. Sequence alignments of each of the NDH subunits show similarities to the sequences of eukaryotic xanthine dehydrogenase (XDH) but not to other known molybdenum-containing bacterial enzymes. Based on alignment with XDH it is inferred that the smallest subunit (NDHB) carries an iron-sulphur cluster, that the middle-sized subunit (NDHA) binds FAD, and that the largest NDH subunit (NDHC) corresponds to the molybdopterin-binding domain of XDH. Expression of both the ndh and the 6-hino genes required the presence of nicotine and molybdenum in the culture medium. Tungsten inhibited enzyme activity but not the synthesis of the enzyme protein. The enzyme was found in A. nicotinovorans cells in a soluble form and in a membrane-associated form. In the presence of tungsten the fraction of membrane-associated NDH increased. PMID:7815950

  18. Extreme Exoplanet Direct Imaging: New Results with GPI and SCExAO and the Path to Imaging Another Earth

    NASA Astrophysics Data System (ADS)

    Currie, Thayne

    2015-12-01

    We describe the discovery of a bright, young Kuiper belt-like debris disk around HD 115600, a ˜ 1.4--1.5 M_{⊙}, ˜ 15 Myr old member of the Sco-Cen OB Association. Our H-band coronagraphy/integral field spectroscopy from the Gemini Planet Imager shows the ring has a (luminosity scaled) semi major axis of (˜ 22 AU) ˜ 48 AU, similar to the current Kuiper belt. The disk appears to have neutral scattering dust, is eccentric (e ˜ 0.1--0.2), and could be sculpted by analogues to the outer solar system planets. Spectroscopy of the disk ansae reveal a slightly blue to gray disk color, consistent with major Kuiper belt chemical constituents, where water-ice is a very plausible dominant constituent. Besides being the first object discovered with the next generation of extreme adaptive optics systems (i.e. SCExAO, GPI, SPHERE), HD 115600's debris ring and planetary system provides a key reference point for the early evolution of the solar system, the structure and composition of the Kuiper belt, and the interaction between debris disks and planets.

  19. Multi-wavelength Observations of Blazar AO 0235+164 in the 2008-2009 Flaring State

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cutini, S.; D'Ammando, F.; de Palma, F.; Dermer, C. D.; Silva, E. do Couto e.; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fortin, P.; Fuhrmann, L.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Guiriec, S.; Hadasch, D.; Hayashida, M.; Hughes, R. E.; Itoh, R.; Jóhannesson, G.; Johnson, A. S.; Katagiri, H.; Kataoka, J.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Lee, S.-H.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Mazziotta, M. N.; McEnery, J. E.; Mehault, J.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Naumann-Godo, M.; Nishino, S.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Pelassa, V.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Rastawicki, D.; Razzano, M.; Readhead, A.; Reimer, A.; Reimer, O.; Reyes, L. C.; Richards, J. L.; Sbarra, C.; Sgrò, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Szostek, A.; Takahashi, H.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Waite, A. P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Zimmer, S.; Fermi-LAT Collaboration; Moderski, R.; Nalewajko, K.; Sikora, M.; Villata, M.; Raiteri, C. M.; Aller, H. D.; Aller, M. F.; Arkharov, A. A.; Benítez, E.; Berdyugin, A.; Blinov, D. A.; Boettcher, M.; Bravo Calle, O. J. A.; Buemi, C. S.; Carosati, D.; Chen, W. P.; Diltz, C.; Di Paola, A.; Dolci, M.; Efimova, N. V.; Forné, E.; Gurwell, M. A.; Heidt, J.; Hiriart, D.; Jordan, B.; Kimeridze, G.; Konstantinova, T. S.; Kopatskaya, E. N.; Koptelova, E.; Kurtanidze, O. M.; Lähteenmäki, A.; Larionova, E. G.; Larionova, L. V.; Larionov, V. M.; Leto, P.; Lindfors, E.; Lin, H. C.; Morozova, D. A.; Nikolashvili, M. G.; Nilsson, K.; Oksman, M.; Roustazadeh, P.; Sievers, A.; Sigua, L. A.; Sillanpää, A.; Takahashi, T.; Takalo, L. O.; Tornikoski, M.; Trigilio, C.; Troitsky, I. S.; Umana, G.; GASP-WEBT Consortium; Angelakis, E.; Krichbaum, T. P.; Nestoras, I.; Riquelme, D.; F-GAMMA; Krips, M.; Trippe, S.; Iram-PdBI; Arai, A.; Kawabata, K. S.; Sakimoto, K.; Sasada, M.; Sato, S.; Uemura, M.; Yamanaka, M.; Yoshida, M.; Kanata; Belloni, T.; Tagliaferri, G.; RXTE; Bonning, E. W.; Isler, J.; Urry, C. M.; SMARTS; Hoversten, E.; Falcone, A.; Pagani, C.; Stroh, M.; (Swift-XRT

    2012-06-01

    The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to ?-ray bands between 2008 September and 2009 February. In this paper, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP-WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazar emission models. We find that the ?-ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of the optical/UV synchrotron spectrum. We tentatively interpret this feature as the bulk Compton emission by cold electrons contained in the jet, which requires an accretion disk corona with an effective covering factor of 19% at a distance of 100 R g. We model the broadband spectra with a leptonic model with external radiation dominated by the infrared emission from the dusty torus.

  20. LDEF (Postflight), AO133 : Effect of Space Environment on Space-Based Radar Phased-Array Antenna, Tr

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO133 : Effect of Space Environment on Space-Based Radar Phased-Array Antenna, Tray H07 The postflight photograph was taken in the KSC SAEF II facility after the experiment was removed from the LDEF. The Space-Based Radar (SBR) Phased-Array Antenna occupies a six (6) inch deep LDEF end corner tray located on the space end of the LDEF. A light tan discoloration is visible on the left and lower flanges of the experiment tray and also on the unpainted aluminum filler to the left of the passive part of the experiment. A darker stain has discolored the lower corners of the tray structure. The SBR Phased-Array Antenna experiment, consisting of an active part in the upper half of the tray and a passive part located in the lower half of the experiment tray, appears to be intact with no apparent physical damage. The black thermal coating on the active part of the experiment appears to have changed from a flat black to a dark gray while the coating on the passive part of the experiment appears less degraded. The exposed Kapton specimen surfaces in both the active and passive parts of the experiment appear to have changed from specular to diffuse from exposure to the space environment.

  1. Intracavity KTP optical parametric oscillator driven by a KLM Nd:GGG laser with a single AO modulator

    NASA Astrophysics Data System (ADS)

    Chu, Hongwei; Zhao, Shengzhi; Yang, Kejian; Zhao, Jia; Li, Yufei; Li, Tao; Li, Guiqiu; Li, Dechun; Qiao, Wenchao

    2015-05-01

    An intracavity KTiOPO4 (KTP) optical parametric oscillator (OPO) pumped by a Kerr lens mode-locking (KLM) Nd:GGG laser near 1062 nm with a single AO modulator was realized for the first time. The mode-locking pulses of the signal wave were obtained with a short duration of subnanosecond and a repetition rate of several kilohertz (kHz). Under a diode pump power of 8.25 W, a maximum output power of 104 mW at signal wavelength near 1569 nm was obtained at a repetition rate of 2 kHz. The highest pulse energy and peak power were estimated to be 80 μJ and 102 kW at a repetition rate of 1 kHz, respectively. The shortest pulse duration was measured to be 749 ps. By considering the Gaussian spatial distribution of the photon density and the Kerr-lens effect in the gain medium, a set of the coupled rate equations for QML intracavity optical parametric oscillator are given and the numerical simulations are basically fitted with the experimental results.

  2. A proposed adhesin AoMad1 helps nematode-trapping fungus Arthrobotrys oligospora recognizing host signals for life-style switching.

    PubMed

    Liang, Lianming; Shen, Renfei; Mo, Yuanyuan; Yang, Jinkui; Ji, Xinglai; Zhang, Ke-Qin

    2015-08-01

    The nematode-trapping fungus Arthrobotrys oligospora is an important natural enemy of nematodes. It can capture nematodes by producing a special mycelial structure called adhesive network or trap. The trap is also a signature of the fungus switching from the saprophytic lifestyle to the predacious lifestyle. At present, little is known about the mechanism of lifestyle switch in nematode-trapping fungi. Here we describe the effect of a cell wall protein called AoMad1 on lifestyle switch. The disruption of the AoMad1-encoding gene in A. oligospora resulted in the formation of more traps in the presence of nematodes. Interestingly, the mutant strain was more sensitive to certain nitrogen sources as trap inducers than the wild type strain. The microscopic examinations revealed that the AoMad1-deletion mutant lacked cell surface adhesive materials and the cell wall structures were more porous than wild-type strains. A great of genes were differentially expressed by transcriptomic analysis when trap formation was induced by sodium nitrate compared to the wild type strain, many of them were related to nitrogen metabolism, host-pathogen interaction and mycelia development. The results suggest that AoMad1 plays an important role in life style switching in A. oligospora. PMID:25724687

  3. Since When or How Often? Dissociating the Roles of Age of Acquisition (AoA) and Lexical Frequency in Early Visual Word Processing

    ERIC Educational Resources Information Center

    Adorni, Roberta; Manfredi, Mirella; Proverbio, Alice Mado

    2013-01-01

    The aim of the study was to investigate the effect of both word age of acquisition (AoA) and frequency of occurrence on the timing and topographical distribution of ERP components. The processing of early- versus late-acquired words was compared with that of high-frequency versus low-frequency words. Participants were asked to perform an…

  4. A Diffraction-limited Survey for Direct Detection of Halpha Emitting/Accreting ExtraSolar Planets with the 6.5m Magellan Telescope and the MagAO Visible AO system

    NASA Astrophysics Data System (ADS)

    Close, Laird

    TECHNICAL BACKGROUND: An advanced adaptive secondary mirror (ASM) with 585 actuators was commissioned at the 6.5-m Magellan Telescope at one of the world’s best sites (Las Campanas Observatory; LCO) in Chile. By the end of the commissioning run (April 2013) the MagAO system was regularly producing the highest spatial resolution deep images to date (0.023” deep images at Halpha (0.656 microns); Close et al. 2013). This is due to its 378 corrective modes at 1kHz on a 6.5-m telescope. Strehl ratis>20% at Halpha were obtained in 75% of the seeing statistics at the site. We propose here to utilize MagAO’s absolutely unique ability to take Halpha, continuum (0.643 microns), and L’ (3.8 microns) thermal images (all simultaneously) to carry out a novel survey to: Discover a population of the lowest mass young accreting extrasolar planets imaged to date. to characterize the spatial distribution, and estimate accretion rates, of young extrasolar planets >5AU, to understand the influence of planets on transitional disk gaps. THEORY BACKGROUND: Extrasolar planets are very difficult to image directly since planets become very faint below ~8 Mjup (Jupiter masses) for ages >1 Myr and such massive planets are rare. There is a class of young stars that are still accreting yet have SED (and often imaging) evidence of a lack of dust and gas inside a r=5-140 AU “gap”. These “transitional disks” are believed to be transitioning into “disk free” stars. These gaps are believed to be maintained by planets that continuously clear (though scattering or accretion) the optically thin gaps. Indeed large >10 AU gaps (>few Hill spheres) must be maintained by multiple ~1 Mjup planets (Dodson-Robinson & Salyk 2011). Since gas must pass through each of these gaps to continuously supply the accreting star, simulations suggest that these “gap planets” are also crossing points for these gas streamers on their way to the star. These streamers “force-feed” these planets a steady diet of hydrogen gas. Such planets should then be quite bright in Halpha accretion emission. The key point is that: instead of a steep drop off in the luminosity of the planet’s atmosphere, the accretion luminosity of these planets will just linearly decrease with decreasing mass. At an accretion rate=6e-10 Msun/yr we find low mass (~1 Mjup) accreting gap planets are much (50-1000x) brighter (for 0-3.4 mag of Halpha extinction) in Halpha than at H band. PROOF-OF_CONCEPT: A 3 hour MagAO observation at Halpha of a transitional disk in April 2013 was made. The resulting deep diffraction-limited images discovered (at 10.5 sigma) an Halpha source that was 295% above the continuum just 0.083” from the star (edge of the inner 10 AU disk gap). We also detected (at 5 sigma) an excellent (though much fainter) ~1 Mjup mass Halpha planet candidate located auspiciously at the outer edge (145 AU) of the gap. If confirmed by our “second epoch” follow-up as common proper motion then this would be the lowest mass (~1 Mjup) planet ever imaged. SURVEY: Scaling off of this exciting success we propose to deeply image (120 min) all 14 nearby (D<250pc), bright (R<11 mag) , not edge-on (i<80 deg) , young (~5 Myr) transitional disks with MagAO simultaneously at Halpha and L’. In addition, we will use BrGamma instead of Halpha for 8 additional fainter (111 Mjup in mass, we integrate across our target list and find that, in the worst case of minimal masses (1+/-0.5 Mjup), and 3.4 mag extinction, at least seven ~1 Mjup planets should be discovered by this survey --meeting all three of our science goals above.

  5. A negative phase shift of the winter AO/NAO due to the recent Arctic sea-ice reduction in late autumn

    NASA Astrophysics Data System (ADS)

    Nakamura, Tetsu; Yamazaki, Koji; Iwamoto, Katsushi; Honda, Meiji; Miyoshi, Yasunobu; Ogawa, Yasunobu; Ukita, Jinro

    2015-04-01

    This paper examines the possible linkage between the recent reduction in Arctic sea-ice extent and the wintertime Arctic Oscillation (AO)/North Atlantic Oscillation (NAO). Observational analyses using the ERA interim reanalysis and merged Hadley/Optimum Interpolation Sea Surface Temperature data reveal that a reduced (increased) sea-ice area in November leads to more negative (positive) phases of the AO and NAO in early and late winter, respectively. We simulate the atmospheric response to observed sea-ice anomalies using a high-top atmospheric general circulation model (AGCM for Earth Simulator, AFES version 4.1). The results from the simulation reveal that the recent Arctic sea-ice reduction results in cold winters in mid-latitude continental regions, which are linked to an anomalous circulation pattern similar to the negative phase of AO/NAO with an increased frequency of large negative AO events by a factor of over two. Associated with this negative AO/NAO phase, cold air advection from the Arctic to the mid-latitudes increases. We found that the stationary Rossby wave response to the sea-ice reduction in the Barents Sea region induces this anomalous circulation. We also found a positive feedback mechanism resulting from the anomalous meridional circulation that cools the mid-latitudes and warms the Arctic, which adds an extra heating to the Arctic air column equivalent to about 60% of the direct surface heat release from the sea-ice reduction. The results from this high-top model experiment also suggested a critical role of the stratosphere in deepening the tropospheric annular mode and modulation of the NAO in mid to late winter through stratosphere-troposphere coupling.

  6. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11 EL-1994-00299 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a light brown stain. Outlines of experiment tray clamp blocks are faint but visible on the upper and lower experiment tray flanges.The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal covers surface appears to have changed from specular to opaque with many black dots of various sizes that appear to be impact craters. Many of the craters appear to have a black center encircled by a brown halo and then by a white halo. Other white circular discolorations also appear on the cover surface. The darker discolorations probably result from an impact that penetrates the 5 mil TEFLON® film and allows atomic oxygen to oxidize and/or erode the vapor deposited silver layer beneath. The black feather shaped discoloration in the lower center of the thermal cover did not appear in the flight photograph and appears to be a particle from a degraded experiment that has attached itself to the cover. The cover is not stretched as taut as in the flight photograph and locations of Velcro attach pads are not as prominent. The ground strap appears to be in place with no visible damage but appears to be a deeper copper color.

  7. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D07

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D07 EL-1994-00207 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray D07 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear to be discolored by a light brown stain. An outline of experiment tray clamp block locations is clearly visible on the experiment trays upper flange and to a lesser extent on its lower flange. The holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal covers surface appears specular with green and white discolorations associated with photo lights and reflections of the surrounding area. The black and/or brown dots of various sizes appear to be points of impact and penetration of the TEFLON® cover. The impact point discoloration is probably the results of a penetration in the 5 mil TEFLON® film that affected the vapor deposited silver and inconel layers beneath.. The cover is not as taut as in the flight photograph and locations of the Velcro attach pads are not as prominent. The ground strap appears to be intact with no visible damage but appears to be a darker copper color than in the prelaunch photograph.

  8. LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11 EL-1994-00299 LDEF (Postflight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray C11 The postflight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken in SAEF II at KSC after removal of the experiment tray from the LDEF. The experiment tray flanges appear discolored by a light brown stain. Outlines of experiment tray clamp blocks are faint but visible on the upper and lower experiment tray flanges.The experiment tray holding fixture hardware covers the clamp block areas on the end flanges. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLON® thermal cover. The silvered TEFLON® cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays lower flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal covers surface appears to have changed from specular to opaque with many black dots of various sizes that appear to be impact craters. Many of the craters appear to have a black center encircled by a brown halo and then by a white halo. Other white circular discolorations also appear on the cover surface. The darker discolorations probably result from an impact that penetrates the 5 mil TEFLON® film and allows atomic oxygen to oxidize and/or erode the vapor deposited silver layer beneath. The black feather shaped discoloration in the lower center of the thermal cover did not appear in the flight photograph and appears to be a particle from a degraded experiment that has attached itself to the cover. The cover is not stretched as taut as in the flight photograph and locations of Velcro attach pads are not as prominent. The ground strap appears to be in place with no visible damage but appears to be a deeper copper color.

  9. A classification manager for compositional concept systems exemplarily shown by the AO/ASIF classification of fractures of long bones.

    PubMed

    Schoop, M; Schoop, D; Bernauer, J

    1995-01-01

    Conventional classification and coding systems represent concept systems by strict hierarchical enumeration and are supported by meaningful codes. Compositional classification is a means for representing concept systems by semantic descriptions. Classification is based on the structure of concept descriptions and explicit hierarchical relationships between their constituents. A classification manager will be presented which is based on the BERNWARD model [1]. BERNWARD is a conceptual graphs formalism and allows the constrained composition of concept descriptions by primitive concepts and roles. It stresses the distinction between generic and partitive relations. Concept descriptions can be classified on the basis of structural criteria for subsumption and part-whole relation. The capabilities of the model, compared to the principles of conventional classification and coding systems, will be exemplified by the AO/ASIF classification of fractures of long bones [2]. This classification is based on 2 axes: topography (long bone and segment) and morphology (type, group, subgroup and quality). It consists of the enumeration of all relevant fractures of long bones which are represented by a compositional meaningful code and by a line drawing. In the demonstrated system, the composition of fracture descriptions is supported by lists of terms and by graphics. The interactive selection of concepts from the space of concepts defined by the implemented classifications is supported by combining the following strategies: entering terms, selecting graphics, adding relevant characteristics to a concept selected before, and navigating through various hierarchies e.g.,generic or partitive hierarchies. These strategies are controlled by different types of compositional restrictions which are: role restrictions, hierarchical restrictions, and coordination restrictions. Role restrictions constrain the addition of specializing characteristics to elements of concept descriptions e.g., the possible complexities of fractures are simple, wedge, and multifragmented. Hierarchical restrictions constrain the generic or partitive refinement of concept elements. For example, every long bone can have the segment "proximal metaphyseal," but only tibia/fibula can have the region "malleolar." Coordination restrictions constrain the coordination of concepts e.g., a frontal fracture of the capitellum can affect the trochlea. Therefore, it is allowed to define a frontal fracture of capitellum and trochlea. Medical observations can be documented by association of selected concepts e.g., a fracture of radius and ulna can be associated to the patient Mr. X. The tools implemented for interactive selection of concepts can be used to rescan documented cases. In contrast to common classification systems, a case can be selected by combining different criteria in BERNWARD. It is possible to look for all female patients with a complex fracture of a long bone of the left upper extremity or to look for all bifocal fractures of the forearm with a wedge fracture of the radius. There is no problem to add new knowledge to the classification manager in the form of another classification. A new classification can be built by using elements of old ones e.g., the classification of the human skeleton is also useful for the AO/ASIF classification. Therefore, parts of classifications can be stored on and loaded from the disk by the demonstrated system. he user environment does not have to be changed to document a different area of medicine because of the conceptual representation of medical knowledge in BERNWARD. The user front-end can be used for all classifications e.g., a relational DBMS for Apple Macintosh systems. Some recursive functions are implemented in a linked Prolog system for effective computation of formal relations between concepts. PMID:8591528

  10. Climate change in the 21st century simulated by HadGEM2-AO under representative concentration pathways

    NASA Astrophysics Data System (ADS)

    Baek, Hee-Jeong; Lee, Johan; Lee, Hyo-Shin; Hyun, Yu-Kyung; Cho, ChunHo; Kwon, Won-Tae; Marzin, Charline; Gan, Sun-Yeong; Kim, Min-Ji; Choi, Da-Hee; Lee, Jonghwa; Lee, Jaeho; Boo, Kyung-On; Kang, Hyun-Suk; Byun, Young-Hwa

    2013-11-01

    We present climate responses of Representative Concentration Pathways (RCPs) using the coupled climate model HadGEM2-AO for the Coupled Model Intercomparison Project phase 5 (CMIP5). The RCPs are selected as standard scenarios for the IPCC Fifth Assessment Report and these scenarios include time paths for emissions and concentrations of greenhouse gas and aerosols and land-use/land cover. The global average warming and precipitation increases for the last 20 years of the 21st century relative to the period 1986-2005 are +1.1°C/+2.1% for RCP2.6, +2.4°C/+4.0% for RCP4.5, +2.5°C/+3.3% for RCP6.0 and +4.1°C/+4.6% for RCP8.5, respectively. The climate response on RCP 2.6 scenario meets the UN Copenhagen Accord to limit global warming within two degrees at the end of 21st century, the mitigation effect is about 3°C between RCP2.6 and RCP8.5. The projected precipitation changes over the 21st century are expected to increase in tropical regions and at high latitudes, and decrease in subtropical regions associated with projected poleward expansions of the Hadley cell. Total soil moisture change is projected to decrease in northern hemisphere high latitudes and increase in central Africa and Asia whereas near-surface soil moisture tends to decrease in most areas according to the warming and evaporation increase. The trend and magnitude of future climate extremes are also projected to increase in proportion to radiative forcing of RCPs. For RCP 8.5, at the end of the summer season the Arctic is projected to be free of sea ice.

  11. Practical experience with test-driven development during commissioning of the multi-star AO system ARGOS

    NASA Astrophysics Data System (ADS)

    Kulas, M.; Borelli, Jose Luis; Gässler, Wolfgang; Peter, Diethard; Rabien, Sebastian; Orban de Xivry, Gilles; Busoni, Lorenzo; Bonaglia, Marco; Mazzoni, Tommaso; Rahmer, Gustavo

    2014-07-01

    Commissioning time for an instrument at an observatory is precious, especially the night time. Whenever astronomers come up with a software feature request or point out a software defect, the software engineers have the task to find a solution and implement it as fast as possible. In this project phase, the software engineers work under time pressure and stress to deliver a functional instrument control software (ICS). The shortness of development time during commissioning is a constraint for software engineering teams and applies to the ARGOS project as well. The goal of the ARGOS (Advanced Rayleigh guided Ground layer adaptive Optics System) project is the upgrade of the Large Binocular Telescope (LBT) with an adaptive optics (AO) system consisting of six Rayleigh laser guide stars and wavefront sensors. For developing the ICS, we used the technique Test- Driven Development (TDD) whose main rule demands that the programmer writes test code before production code. Thereby, TDD can yield a software system, that grows without defects and eases maintenance. Having applied TDD in a calm and relaxed environment like office and laboratory, the ARGOS team has profited from the benefits of TDD. Before the commissioning, we were worried that the time pressure in that tough project phase would force us to drop TDD because we would spend more time writing test code than it would be worth. Despite this concern at the beginning, we could keep TDD most of the time also in this project phase This report describes the practical application and performance of TDD including its benefits, limitations and problems during the ARGOS commissioning. Furthermore, it covers our experience with pair programming and continuous integration at the telescope.

  12. LDEF (Prelaunch), AO133 : Effect of Space Environment on Space-Based Radar Phased-Array Antenna, Tra

    NASA Technical Reports Server (NTRS)

    1984-01-01

    LDEF (Prelaunch), AO133 : Effect of Space Environment on Space-Based Radar Phased-Array Antenna, Tray H07 The prelaunch photograph was taken in SAEF II at KSC prior to installation of the integrated tray on the LDEF. The Space-Based Radar (SBR) Phased-Array Antenna Experiment occupies a six (6) inch deep LDEF end corner tray located on the space end of the LDEF. The SBR Phased-Array Antenna experiment consists of both passive and active parts. The passive part , shown in the left half of the experiment tray, investigates the dimensional stability of Kapton when exposed to induced stresses in the space environment. Continuous and spliced specimen of both plain Kapton (127 um thick) and glass reinforced Kapton (196 um thick) will be exposed for the entire mission. The Kapton specimen array contains eight 2.54-cm-wide specimen and sixteen (16) 1.27-cm-wide specimen. The specimen are stretched over an aluminum roller assembly and utilize a spring loaded mechanism to provide preselected stresses. An aluminum support structure houses two (2) identical set of specimen, one exposed to the total environment and one shadowed. The fasteners are non-magnetic stainless steel and the black surface is a thermal control coating, 3M-Nextel 401-610 (Black Velvet). The active part of the experiment, located in the right half of the tray, investigates the interaction between high voltage and low-Earth-orbit plasma. A fourteen (14) inch wide by twenty eight (28) inch long section of the Grumman SBR Phased-Array antenna consisting of two Kapton antenna planes and a perforated aluminum ground plane mounted on an aluminum support structure. Cop- per dipole elements deposited on the Kapton antenna plane provide the high voltage electrodes. The fasteners are non-magnetic stainless steel and the black surface is a thermal control coating, 3M-Nextel 401-610 (Black Velvet).

  13. Molecular dynamics evidence for alkali-metal rattling in the ?-pyrochlores, AOs2O6 (A = K, Rb, Cs).

    PubMed

    Shoko, E; Peterson, V K; Kearley, G J

    2013-11-27

    We have used ab initio molecular dynamics simulations validated against inelastic neutron scattering data to study alkali-metal dynamics in the ?-pyrochlore osmates AOs2O6 (A=K, Rb, Cs) at 300 K to gain insight into the microscopic nature of rattling dynamics in these materials. Our results provide new evidence at the microscopic level for rattling dynamics: (1) the elemental magnitude spectra calculated from the MD show a striking dominance by the alkali metals at low energies indicating weak coupling to the cage, (2) the atomic root-mean-square displacements for the alkali metals are significantly larger than for the other atoms, e.g., 25% and 150% larger than O and Os, respectively, in KOs2O6, and (3) motions of the alkali metals are weakly correlated to the dynamics in their immediate environment, e.g. K in KOs2O6 is 6 times less sensitive to its local environment than Os, indicating weak bonding of the K. There is broadening of the elemental spectra of the alkali metals from Cs to K corresponding to a similar broadening of the local potential around these atoms as determined from potential of mean-force calculations. This feature of the spectra is partly explained by the well-known increase in the relative cage volume with decreasing atomic size of the alkali metal. We find that for the smallest rattler in this series (K) the larger relative cage volume allows this atom freedom to explore a large space inside the cage leading to vibration at a broader range of frequencies, hence a broader spectrum. Thus, since K is considered the best rattler in this series, these findings suggest that a significant feature of a good rattler is the ability to vibrate at several different but closely spaced frequencies. PMID:24172693

  14. Magellan Adaptive Optics First-light Observations of the Exoplanet ? Pic B. I. Direct Imaging in the Far-red Optical with MagAO+VisAO and in the Near-ir with NICI

    NASA Astrophysics Data System (ADS)

    Males, Jared R.; Close, Laird M.; Morzinski, Katie M.; Wahhaj, Zahed; Liu, Michael C.; Skemer, Andrew J.; Kopon, Derek; Follette, Katherine B.; Puglisi, Alfio; Esposito, Simone; Riccardi, Armando; Pinna, Enrico; Xompero, Marco; Briguglio, Runa; Biller, Beth A.; Nielsen, Eric L.; Hinz, Philip M.; Rodigas, Timothy J.; Hayward, Thomas L.; Chun, Mark; Ftaclas, Christ; Toomey, Douglas W.; Wu, Ya-Lin

    2014-05-01

    We present the first ground-based CCD (? < 1 ?m) image of an extrasolar planet. Using the Magellan Adaptive Optics system's VisAO camera, we detected the extrasolar giant planet ? Pictoris b in Y-short (YS , 0.985 ?m), at a separation of 0.470 ± 0.''010 and a contrast of (1.63 ± 0.49) × 10-5. This detection has a signal-to-noise ratio of 4.1 with an empirically estimated upper limit on false alarm probability of 1.0%. We also present new photometry from the Gemini Near-Infrared Coronagraphic Imager instrument on the Gemini South telescope, in CH 4S,1% (1.58 ?m), KS (2.18 ?m), and K cont (2.27 ?m). A thorough analysis of our photometry combined with previous measurements yields an estimated near-IR spectral type of L2.5 ± 1.5, consistent with previous estimates. We estimate log (L bol/L ?) = -3.86 ± 0.04, which is consistent with prior estimates for ? Pic b and with field early-L brown dwarfs (BDs). This yields a hot-start mass estimate of 11.9 ± 0.7 M Jup for an age of 21 ± 4 Myr, with an upper limit below the deuterium burning mass. Our L bol-based hot-start estimate for temperature is T eff = 1643 ± 32 K (not including model-dependent uncertainty). Due to the large corresponding model-derived radius of R = 1.43 ± 0.02 R Jup, this T eff is ~250 K cooler than would be expected for a field L2.5 BD. Other young, low-gravity (large-radius), ultracool dwarfs and directly imaged EGPs also have lower effective temperatures than are implied by their spectral types. However, such objects tend to be anomalously red in the near-IR compared to field BDs. In contrast, ? Pic b has near-IR colors more typical of an early-L dwarf despite its lower inferred temperature.

  15. Magellan adaptive optics first-light observations of the exoplanet ? PIC b. I. Direct imaging in the far-red optical with MagAO+VisAO and in the near-IR with NICI {sup ,}

    SciTech Connect

    Males, Jared R.; Close, Laird M.; Morzinski, Katie M.; Skemer, Andrew J.; Kopon, Derek; Follette, Katherine B.; Hinz, Philip M.; Rodigas, Timothy J.; Wahhaj, Zahed; Liu, Michael C.; Nielsen, Eric L.; Chun, Mark; Puglisi, Alfio; Esposito, Simone; Riccardi, Armando; Pinna, Enrico; Xompero, Marco; Briguglio, Runa; Hayward, Thomas L. [Gemini Observatory, Southern Operations Center, c and others

    2014-05-01

    We present the first ground-based CCD (? < 1 ?m) image of an extrasolar planet. Using the Magellan Adaptive Optics system's VisAO camera, we detected the extrasolar giant planet ? Pictoris b in Y-short (Y{sub S} , 0.985 ?m), at a separation of 0.470 ± 0.''010 and a contrast of (1.63 ± 0.49) × 10{sup –5}. This detection has a signal-to-noise ratio of 4.1 with an empirically estimated upper limit on false alarm probability of 1.0%. We also present new photometry from the Gemini Near-Infrared Coronagraphic Imager instrument on the Gemini South telescope, in CH {sub 4S,1%} (1.58 ?m), K{sub S} (2.18 ?m), and K {sub cont} (2.27 ?m). A thorough analysis of our photometry combined with previous measurements yields an estimated near-IR spectral type of L2.5 ± 1.5, consistent with previous estimates. We estimate log (L {sub bol}/L {sub ?}) = –3.86 ± 0.04, which is consistent with prior estimates for ? Pic b and with field early-L brown dwarfs (BDs). This yields a hot-start mass estimate of 11.9 ± 0.7 M {sub Jup} for an age of 21 ± 4 Myr, with an upper limit below the deuterium burning mass. Our L {sub bol}-based hot-start estimate for temperature is T {sub eff} = 1643 ± 32 K (not including model-dependent uncertainty). Due to the large corresponding model-derived radius of R = 1.43 ± 0.02 R {sub Jup}, this T {sub eff} is ?250 K cooler than would be expected for a field L2.5 BD. Other young, low-gravity (large-radius), ultracool dwarfs and directly imaged EGPs also have lower effective temperatures than are implied by their spectral types. However, such objects tend to be anomalously red in the near-IR compared to field BDs. In contrast, ? Pic b has near-IR colors more typical of an early-L dwarf despite its lower inferred temperature.

  16. SIMS chemical analysis of extended impacts on the leading and trailing edges of LDEF experiment AO187-2

    NASA Technical Reports Server (NTRS)

    Amari, S.; Foote, J.; Simon, Charles G.; Swan, P.; Walker, R. M.; Zinner, E.; Jessberger, E. K.; Lange, G.; Stadermann, F.

    1992-01-01

    The Long Duration Exposure Facility (LDEF) Experiment AO187-2 consisted of 237 capture cells, 120 on the leading edge and 117 on the trailing edge. Each cell was made of polished Ge plates covered with 2.5 micron thick mylar foil at 200 microns from the Ge. Although all leading edge cells and 105 trailing edge cells had lost their plastic covers during flight, optical and electron microscope examination revealed extended impacts in bare cells from either edge that apparently were produced by high velocity projectiles while the plastic foils were still in place. Detailed optical scanning yielded 53 extended impacts on 100 bare cells from the trailing edge that were selected for SIMS chemical analysis. Lateral multi-element ion probe profiles were obtained on 40 of these impacts. Material that can be attributed to the incoming projectiles was found in all analyzed extended compact features and most seem to be associated with cosmic dust particles. However, LDEF deposits are systematically enriched in the refractory elements Al, Ca, and Ti relative to Mg and Fe when compared to IDP's collected in the stratosphere and to chondritic compositions. These differences are most likely due to elemental fractionation effects during the high velocity impact but real differences between interplanetary particles captured on LDEF and stratospheric IDP's cannot be excluded. Recently we extended our studies to cells from the leading edge and the covered cells from the trailing edge. The 12 covered cells contain 20 extended impact candidates. Ion probe analysis of 3 yielded results similar to those obtained for impacts on the bare cells from the trailing edge. Optical scanning of the bare leading edge cell also reveals many extended impacts (42 on 22 cells scanned to date), demonstrating that the cover foils remained intact at least for some time. However, SIMS analysis showed elements that can reasonably be attributed to micrometeoroids in only 2 out of 11 impacts. Eight impacts have residues dominated by Al and one dominated by Ti, indicating a preponderance of orbital debris in leading edge impacts.

  17. SIMS chemical analysis of extended impacts on the leading and trailing edges of LDEF experiment AO187-2

    NASA Astrophysics Data System (ADS)

    Amari, S.; Foote, J.; Simon, Charles G.; Swan, P.; Walker, R. M.; Zinner, E.; Jessberger, E. K.; Lange, G.; Stadermann, F.

    1992-06-01

    The Long Duration Exposure Facility (LDEF) Experiment AO187-2 consisted of 237 capture cells, 120 on the leading edge and 117 on the trailing edge. Each cell was made of polished Ge plates covered with 2.5 micron thick mylar foil at 200 microns from the Ge. Although all leading edge cells and 105 trailing edge cells had lost their plastic covers during flight, optical and electron microscope examination revealed extended impacts in bare cells from either edge that apparently were produced by high velocity projectiles while the plastic foils were still in place. Detailed optical scanning yielded 53 extended impacts on 100 bare cells from the trailing edge that were selected for SIMS chemical analysis. Lateral multi-element ion probe profiles were obtained on 40 of these impacts. Material that can be attributed to the incoming projectiles was found in all analyzed extended compact features and most seem to be associated with cosmic dust particles. However, LDEF deposits are systematically enriched in the refractory elements Al, Ca, and Ti relative to Mg and Fe when compared to IDP's collected in the stratosphere and to chondritic compositions. These differences are most likely due to elemental fractionation effects during the high velocity impact but real differences between interplanetary particles captured on LDEF and stratospheric IDP's cannot be excluded. Recently we extended our studies to cells from the leading edge and the covered cells from the trailing edge. The 12 covered cells contain 20 extended impact candidates. Ion probe analysis of 3 yielded results similar to those obtained for impacts on the bare cells from the trailing edge. Optical scanning of the bare leading edge cell also reveals many extended impacts (42 on 22 cells scanned to date), demonstrating that the cover foils remained intact at least for some time. However, SIMS analysis showed elements that can reasonably be attributed to micrometeoroids in only 2 out of 11 impacts. Eight impacts have residues dominated by Al and one dominated by Ti, indicating a preponderance of orbital debris in leading edge impacts.

  18. HIGH-RESOLUTION IMAGES OF ORBITAL MOTION IN THE ORION TRAPEZIUM CLUSTER WITH THE LBT AO SYSTEM

    SciTech Connect

    Close, L. M.; Males, J. R.; Skemer, A.; McCarthy, D. W.; Xompero, M.; Kulesa, C.; Puglisi, A.; Busoni, L.; Pinna, E.; Riccardi, A.; Quiros-Pacheco, F.; Argomedo, J.; Esposito, S.; Mannucci, F.; Arcidiacono, C.; Guerra, J. C.; Brusa, G.; Miller, D. L.; Brynnel, J.; Boutsia, K.; and others

    2012-04-20

    The new 8.4 m LBT adaptive secondary AO system, with its novel pyramid wavefront sensor, was used to produce very high Strehl ({approx}> 75% at 2.16 {mu}m) near-infrared narrowband (Br{gamma}: 2.16 {mu}m and [Fe II]: 1.64 {mu}m) images of 47 young ({approx}1 Myr) Orion Trapezium {theta}{sup 1} Ori cluster members. The inner {approx}41 Multiplication-Sign 53'' of the cluster was imaged at spatial resolutions of {approx}0.''050 (at 1.64 {mu}m). A combination of high spatial resolution and high S/N yielded relative binary positions to {approx}0.5 mas accuracies. Including previous speckle data, we analyze a 15 year baseline of high-resolution observations of this cluster. We are now sensitive to relative proper motions of just {approx}0.3 mas yr{sup -1} (0.6 km s{sup -1} at 450 pc); this is a {approx}7 Multiplication-Sign improvement in orbital velocity accuracy compared to previous efforts. We now detect clear orbital motions in the {theta}{sup 1} Ori B{sub 2} B{sub 3} system of 4.9 {+-} 0.3 km s{sup -1} and 7.2 {+-} 0.8 km s{sup -1} in the {theta}{sup 1} Ori A{sub 1} A{sub 2} system (with correlations of P.A. versus time at >99% confidence). All five members of the {theta}{sup 1} Ori B system appear likely a gravitationally bound 'mini-cluster'. The very lowest mass member of the {theta}{sup 1} Ori B system (B{sub 4}; mass {approx}0.2 M{sub Sun }) has, for the first time, a clearly detected motion (at 4.3 {+-} 2.0 km s{sup -1}; correlation = 99.7%) w.r.t. B{sub 1}. However, B{sub 4} is most likely in a long-term unstable (non-hierarchical) orbit and may 'soon' be ejected from this 'mini-cluster'. This 'ejection' process could play a major role in the formation of low-mass stars and brown dwarfs.

  19. Time Differential Electrical Resistivity for Water Resource Assessment: A Case Study in Cura‡ao, Netherlands Antilles

    NASA Astrophysics Data System (ADS)

    Coles, D.; Vichabian, Y.; Sogade, J.; Spiertz, P.; Morgan, F. D.

    2003-12-01

    A method of groundwater prospecting is presented that capitalizes on changes in electrical resistivity arising from annual variability in subsurface fluid flow. According to Archie's Law, effective resistivity is a function of pore fluid resistivity, saturation, and porosity. For competent Earth materials, short-term temporal changes in near-surface porosity are negligible because changes in effective pressure are small with respect to the bulk moduli of the materials. Therefore, annual variability in effective resistivity is dependent only on fluid flow via changes in saturation and, to a lesser extent, pore fluid resistivity. Aquifer detection is but the first step; thereafter, it is necessary to estimate permeability, capacity, and, importantly, sustainability. Time differential resistivity is well matched to the task because it detects prospective aquifers and also illuminates their natural hydrodynamics. Explicitly, this method captures an undeveloped aquifer's seasonal volumetric variability, which is important as engineers reconcile monthly demand with monthly supply. The best scenario would be to detect a capacious, intermediate-resistivity (high pore fluid resistivity and high porosity) zone that is invariant from season to season (clays and ore bodies excepted). Less desirable, but still manageable, is the case where a large, porous formation undergoes significant seasonal resistivity variation; it behaves as a subterranean river with little lag-time between meteoric water input and groundwater throughput; carefully timed extraction and storage would be required in this case. A suite of thirty-eight electrical resistivity soundings were collected from the wet and dry seasons at Plantages PortoMari, an ecotourist plantation on the semiarid island of Cura‡ao, N.A. The data were analyzed with special attention paid to wet-to-dry season resistivity ratios. The results suggest two possible courses of action. (1) A hypothetical limestone terrace was detected whose estimated minimum water volume fluctuates between approximately 1200m3 and 2300m3; this terrace may be tapped with several boreholes descending to an elevation of 25m ASL. (2) A shallow subsurface dam and extraction fence (10m BGS) might be installed where the watershed corridor converges onto a flat plain whose surficial lithology is comprised of poorly sorted alluvia atop an impermeable clayey unit. Both extraction scenarios require storage facilities, as neither hydrogeologic setting indicates a persistent aquifer.

  20. LDEF (Flight), AO175 : Evaluation of Long-Duration Exposure to the Natural Space Environment on Grap

    NASA Technical Reports Server (NTRS)

    1990-01-01

    LDEF (Flight), AO175 : Evaluation of Long-Duration Exposure to the Natural Space Environment on Graphite-Polyimide and Graphite-Epoxy Mechanical Properties, Tray A07 The flight photograph was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The paint dots on the tray clampblocks have changed little from the orginal white color. The dots along the lower tray flange seem to have a faint light brown tint. The dull gold coating observed on the aluminum mounting strips in the prelaunch photograph has turned to a medium brown. The areas where the coating was scraped or abraided away appears as a metallic surface. PMR-15 Graphite-Polyimide Panel (precured) - The PMR-15 graphite-polyimide laminated panel (T40T30060-009) appears to have changed from the prelaunch brown color to a light gray. A geometric pattern, probably the results of the laminating process, is visible on the panel surface. Fine horizontal lines, cracks and/or crazing, can be seen over the geometrical pattern. The yellow colored identification numbers seem to be a little darker in the flight photograph but the white marking in the upper left corner do not appear to have changed. Scratch marks / abrasions on the lower left edge of panel were on prelaunch photographs. F-178/T300 Graphite-Polyimide Panel (cocured) - The 178/T300 graphite-polyimide panel (T40T30060-005) seems to have changed from the pre-launch dark brown to a light gray color. The yellow identification numbers seem darker in the flight photograph while the white marking in the upper left corner appear brighter. There appears to be fine horizontal lines, cracks and/or crazing, on the panel surface. F178/T300 Graphite-Polyimide Panel (precured) - The 178/T300 graphite-polyimide laminated panel (T40T30060-001) seems to have changed from the prelaunch dark brown color with a lighter brown area along its vertical center, extending from top to bottom, to a uniform light gray color. The yellow identification numbers seem to be a little darker than in the prelaunch photograph. The white marking seen on the lower right corner of the panel appeared to be off-white in the prelaunch photograph. There appears to be fine horizontal lines, cracks and/or crazing, on the panel surface.

  1. LDEF (Prelaunch), AO175 : Evaluation of Long-Duration Exposure to the Natural Space Environment on G

    NASA Technical Reports Server (NTRS)

    1984-01-01

    LDEF (Prelaunch), AO175 : Evaluation of Long-Duration Exposure to the Natural Space Environment on Graphite-Polyimide and Graphite-Epoxy Mechanical Properties, Tray A07 The Graphite-Polyimide and Graphite-Epoxy Mechanical Properties experiment fills two (2) three (3) inch deep peripheral trays, A01 and A07. The experiment in the A07 experiment tray, shown in this photograph, consist of three (3) Graphite-Polyimide laminate panels and associated mounting hardware. Each panel occupies one third (1/3) of the LDEF experiment tray; a PMR-15 precured graphite-polyimide panel (T40T30060-009) in the right one third section, a F-178/T300 cocured graphite-polyimide panel (T40T30060-005) in the center one third section and a F-178/T300 precured graphite-polyimide panel (T40T30060-001) is in the left one third section of the tray. The panels are held in place with aluminum strips and non-magnetic stainless steel fasteners. The aluminum strips are covered with a dull gold coating over most of the exposed surface. The coating has been scraped from the aluminum mounting strip near the upper left tray corner. The mounting system, designed to allow for differential thermal expansion, minimizes the risk of inducing high stresses into the test panels. PMR-15 Graphite-Polyimide Panel (precured) - The PMR-15 graphite-polyimide laminated panel (T40T30060-009) is a uniform dark brown with a yellow identification number. The panel has several off-white marks in the lower right corner and light grayish-brown discolorations can be seen behind the identification number and behind the off-white marks. F-178/T300 Graphite-Polyimide Panel (cocured) - The F178/T300 graphite-polyimide laminated panel (T40T30060-005) is also a dark brown with a yellow identification number and small offwhite marks in the lower right corner. F-178/300 Graphite-Polyimide Panel (precured) - The F178/300 graphite-polyimide laminated panel (T40T30060-001) is a dark brown color with a yellow identification number and small offwhite marks in the panels upper left corner. The panel appears to have a lighter brown area along its vertical center that extends from the bottom to the top of the panel.

  2. Study of the blazar AO 0235+164 during the multi-wavelength observation period from October 2008 to February 2009

    NASA Astrophysics Data System (ADS)

    Rainò, S.; Madejski, G.; do Couto e Silva, E.; Gargano, F.; Reyes, L.; Nalewajko, K.; Sikora, M.

    2013-06-01

    AO 0235+164 is one of the most studied and monitored BL Lac objects in the sky. Since the launch of Fermi, the source has been monitored in the gamma-ray band by Fermi Large Area Telescope. Starting in October 2008, AO 0235+164 showed an increasing activity in gamma-rays that led to a multi-wavelength campaign with instruments in the radio, near-infrared, optical, UV and X-ray bands. We present here the results of the analysis of the multi-wavelength data collected during the flaring period: the high variability properties of this source and the SED built from radio frequencies to gamma-rays are shown, and are interpreted in the context of well-known blazar emission models [Ackermann, M. et al. 2012, ApJ 751, 159].

  3. Site symmetry of AO{sub 4} complexes (A are s- or p-elements of periods III and IV) in crystal structures

    SciTech Connect

    Serezhkin, V. N. Savchenkov, A. V.; Urusov, V. S.

    2010-03-15

    The symmetry of the sites occupied in crystal structures by 17 405 crystallographically different A atoms (A are s or p elements of periods III and IV) entering the composition of AO{sub 4}{sup z-} complexes has been analyzed. A periodicity in the ability of A atoms for implementing a certain site symmetry is established. Some features of the stereochemistry of A elements in the dependence of their position in the periodic table are discussed.

  4. ViLLaGEs: opto-mechanical design of an on-sky visible-light MEMS-based AO system

    NASA Astrophysics Data System (ADS)

    Grigsby, Bryant; Lockwood, Chris; Baumann, Brian; Gavel, Don; Johnson, Jess; Ammons, S. Mark; Dillon, Daren; Morzinski, Katie; Reinig, Marc; Palmer, Dave; Severson, Scott; Gates, Elinor

    2008-07-01

    Visible Light Laser Guidestar Experiments (ViLLaGEs) is a new Micro-Electro Mechanical Systems (MEMS) based visible-wavelength adaptive optics (AO) testbed on the Nickel 1-meter telescope at Lick Observatory. Closed loop Natural Guide Star (NGS) experiments were successfully carried out during engineering during the fall of 2007. This is a major evolutionary step, signaling the movement of AO technologies into visible light with a MEMS mirror. With on-sky Strehls in I-band of greater than 20% during second light tests, the science possibilities have become evident. Described here is the advanced engineering used in the design and construction of the ViLLaGEs system, comparing it to the LickAO infrared system, and a discussion of Nickel dome infrastructural improvements necessary for this system. A significant portion of the engineering discussion revolves around the sizable effort that went towards eliminating flexure. Then, we detail upgrades to ViLLaGEs to make it a facility class instrument. These upgrades will focus on Nyquist sampling the diffraction limited point spread function during open loop operations, motorization and automation for technician level alignments, adding dithering capabilities and changes for near infrared science.

  5. Kahua A'o: A Learning Foundation: Using Hawaiian Language Newspaper Articles for Place and Culture-based Geoscience Teacher Education and Curriculum Development

    NASA Astrophysics Data System (ADS)

    Ellinwood, I.; Stone, K.; Spencer, L.

    2012-12-01

    Kahua A'o is a collaborative project funded by the National Science Foundation aimed at developing science curriculum grounded in Hawaiian culture and place-based education. The project team is composed of members who contribute expertise in meteorology, geology, curriculum development, and Hawaiian language. To date, six lessons have been produced, four with a focus in meteorology and two with a focus in geology. The lessons are geared towards the middle school level, but can easily be adapted for other levels. Each lesson combines a scientific topic with relevant Hawaiian language resources. Serving as the main source for resources is the Hawaiian language newspaper archive, which is an online database of 75,000 pages from newspapers that were published between 1834 and 1948. By incorporating Hawaiian language newspaper articles into science lessons, we aim to teach science through culture and show a history of scientific inquiry intrinsic to Hawaiian culture in order to generate more interest in science among Hawai'i students, especially native Hawaiian students, who are underrepresented in scientific fields. Since most of the articles are specific to the Hawaiian Islands, all students will find more relevance with the lesson through place-based education. Kahua A'o lessons are currently being piloted with groups of public school teachers. Bishop Museum is also incorporating elements of the meteorology lessons into their science education curriculum. The goal of Kahua A'o is to become the first of many such interdisciplinary collaborations, especially those that utilize the rich repository of untapped knowledge in the Hawaiian language newspaper archive.

  6. Characterization of PmfR, the Transcriptional Activator of the pAO1-Borne purU-mabO-folD Operon of Arthrobacter nicotinovorans

    PubMed Central

    Chiribau, Calin B.; Sandu, Cristinel; Igloi, Gabor L.; Brandsch, Roderich

    2005-01-01

    Nicotine catabolism by Arthrobacter nicotinovorans is linked to the presence of the megaplasmid pAO1. Genes involved in this catabolic pathway are arranged on the plasmid into gene modules according to function. During nicotine degradation ?-N-methylaminobutyrate is formed from the pyrrolidine ring of nicotine. Analysis of the pAO1 open reading frames (ORF) resulted in identification of the gene encoding a demethylating ?-N-methylaminobutyrate oxidase (mabO). This gene was shown to form an operon with purU- and folD-like genes. Only in bacteria grown in the presence of nicotine could transcripts of the purU-mabO-folD operon be detected, demonstrating that this operon constitutes part of the pAO1 nicotine regulon. Its transcriptional start site was determined by primer extension analysis. Transcription of the operon was shown to be controlled by a new transcriptional regulator, PmfR, the product of a gene that is transcribed divergently from the purU, mabO, and folD genes. PmfR was purified, and electromobility shift assays and DNase I-nuclease digestion experiments were used to determine that its DNA binding site is located between ?48 and ?88 nucleotides upstream of the transcriptional start site of the operon. Disruption of pmfR by homologous recombination with a chloramphenicol resistance cassette demonstrated that PmfR acts in vivo as a transcriptional activator. Mutagenesis of the PmfR target DNA suggested that the sequence GTTT-14 bp-AAAC is the core binding site of the regulator upstream of the ?35 promoter region of the purU-mabO-folD operon. PMID:15838033

  7. [Effects of dissolved oxygen in the oxic parts of A/O reactor on degradation of organic pollutants and analysis of microbial community for treating petrochemical wastewater].

    PubMed

    Ding, Peng-Yuan; Chu, Li-Bing; Zhang, Nan; Wang, Xing; Wang, Jian-Long

    2015-02-01

    Effects of dissolved oxygen (DO) on the biodegradation of organic pollutants were investigated using A/O reactors for the treatment of actual petrochemical wastewater. Two A/O reactors, DO were controlled at 2-3 mg x L(-1) in the oxic parts of reactor A and 5-6 mg x L(-1) of reactor B, were operated in parallel for comparison. The nearly a half of year operation results showed that the effluent COD in reactor A (72.5 ± 14.8 mg x L(-1)) was slightly higher than that in reactor B (68.7 ± 14.6 mg x L(-1)) at a HRT of 20 h. The average COD removal efficiencies were 67.0% and 68.8%, respectively. The effluent ammonium concentration was maintained at 0.8 mg x L(-1) and approximately 95% of ammonium removal was achieved. The effluent BOD, concentration was lower than 5 mg x L(-1). This indicated that the organic pollutants could be degraded thoroughly by the A/O processes, which were affected slightly by DO. Results of 454 pyrosequencing analysis of the sludge in oxic parts showed that at the phylum levels, sequences belonged to Proteobacteria, Planctomycetes and Bacteroidetes were abundant with 58.7% and 59.2%, 14.7% and 12.7%, 10.8% and 12.4% of total bacterial sequences in reactor A and B, respectively. Ammonium oxidation bacteria Nitrosomonas, nitrite oxidizing bacteria Nitrospira and obligate aerobic bacteria were highly enriched in reactor B with high DO levels, while the anaerobic denitrifiers Azospira and Acidovora were highly enriched in reactor A with low DO levels. The identified bacteria belonged to genera Novosphingobium, Comamonas, Sphingobium and Altererythrobacter were reported to degrade PAHs, chloronitrobenzene, pesticides and petroleum, which contributed to the degradation of petrochemical wastewater. PMID:26031089

  8. The a subunit of the A1AO ATP synthase of Methanosarcina mazei Gö1 contains two conserved arginine residues that are crucial for ATP synthesis.

    PubMed

    Gloger, Carolin; Born, Anna-Katharina; Antosch, Martin; Müller, Volker

    2015-01-01

    Like the evolutionary related F1FO ATP synthases and V1VO ATPases, the A1AO ATP synthases from archaea are multisubunit, membrane-bound transport machines that couple ion flow to the synthesis of ATP. Although the subunit composition is known for at least two species, nothing is known so far with respect to the function of individual subunits or amino acid residues. To pave the road for a functional analysis of A1AO ATP synthases, we have cloned the entire operon from Methanosarcina mazei into an expression vector and produced the enzyme in Escherichia coli. Inverted membrane vesicles of the recombinants catalyzed ATP synthesis driven by NADH oxidation as well as artificial driving forces. [Formula: see text] as well as ?pH were used as driving forces which is consistent with the inhibition of NADH-driven ATP synthesis by protonophores. Exchange of the conserved glutamate in subunit c led to a complete loss of ATP synthesis, proving that this residue is essential for H+ translocation. Exchange of two conserved arginine residues in subunit a has different effects on ATP synthesis. The role of these residues in ion translocation is discussed. PMID:25724672

  9. The stimulating role of subunit F in ATPase activity inside the A1-complex of the Methanosarcina mazei Gö1 A1AO ATP synthase.

    PubMed

    Singh, Dhirendra; Sielaff, Hendrik; Sundararaman, Lavanya; Bhushan, Shashi; Grüber, Gerhard

    2016-02-01

    A1AO ATP synthases couple ion-transport of the AO sector and ATP synthesis/hydrolysis of the A3B3-headpiece via their stalk subunits D and F. Here, we produced and purified stable A3B3D- and A3B3DF-complexes of the Methanosarcina mazei Gö1 A-ATP synthase as confirmed by electron microscopy. Enzymatic studies with these complexes showed that the M. mazei Gö1 A-ATP synthase subunit F is an ATPase activating subunit. The maximum ATP hydrolysis rates (Vmax) of A3B3D and A3B3DF were determined by substrate-dependent ATP hydrolysis experiments resulting in a Vmax of 7.9s(-1) and 30.4s(-1), respectively, while the KM is the same for both. Deletions of the N- or C-termini of subunit F abolished the effect of ATP hydrolysis activation. We generated subunit F mutant proteins with single amino acid substitutions and demonstrated that the subunit F residues S84 and R88 are important in stimulating ATP hydrolysis. Hybrid formation of the A3B3D-complex with subunit F of the related eukaryotic V-ATPase of Saccharomyces cerevisiae or subunit ? of the F-ATP synthase from Mycobacterium tuberculosis showed that subunit F of the archaea and eukaryotic enzymes are important in ATP hydrolysis. PMID:26682760

  10. Dust and Diffuse Interstellar Bands in the z{sub a} = 0.524 Absorption System toward AO 0235+164

    SciTech Connect

    Junkkarinen, V.

    2004-08-06

    The authors present new HST STIS NUV-MAMA and STIS CCD observations of the BL Lac object AO 0235+164 and the intervening damped Ly {alpha} (DLA) line at z{sub {alpha}} = 0.524. The line profile gives N(HI) = 5 {+-} 1 x 10{sup 21} cm{sup -2} and, combined with the H I 21 cm absorption data leads to a spin temperature of Ts = 220 K {+-} 60 K. Those spectra also show a strong, broad feature at the expected position of the 2175 {angstrom} graphitic dust feature at z{sup {alpha}} = 0.524. Assuming a Galactic type dust extinction curve at z{sub {alpha}} = 0.524 gives a dust-to-gas ratio of 0.19 Galactic, but the fit, assuming the underlying, un-reddened spectrum is a single power-law, is poor in the far-UV. A dust-to-gas ratio of 0.19 Galactic is similar to the LMC, but the AO 0235+164 spectrum does not fit the LMC extinction curve, or the SMC extinction curve (which has practically no 2175 {angstrom} feature). A possible interpretation includes dust similar to Galactic, but with less of the small particles that produce the far-UV extinction. The metallicity of the z{sub {alpha}} = 0.524 absorber, estimated from the observed N(HI) and excess X-ray absorption (beyond Galactic) derived from contemporaneous and archival ASCA and ROSAT.

  11. Comparison of Clinical Outcomes of Phalangeal Fracture Treated with Dorsolateral Approach or Post-middle Approach Using AO Mini Titanium Plate.

    PubMed

    Li, Guang; Liu, Shen; Chen, Guoting; Li, Zengchun; Liu, Yangzhou; Sun, Guixin; Lu, Qingyou; Li, Xia; Tan, Jun; Guan, Ming

    2015-12-01

    The aim of this study is to investigate the clinical outcomes of various fixation methods for proximal phalangeal fractures with Arbeitsgemeinschaft für Osteosynthesefragen (AO) mini titanium plate by dorsolateral approach or post-middle approach. Clinical results of 62 fingers of 53 patients with proximal phalangeal fracture were evaluated. For dorsolateral approach, the lateral bundle of the extensor tendon was drawn away to expose the fracture part of the bone. After reduction, the plate was located at the dorsolateral side of the bone. For post-middle approach, the extensor tendon was split to expose the fracture part of the bone. After reduction, the plate was fixed to the proximal phalangeal side of the bone, and the extensor tendon was repaired with 3-0 nonabsorbable silk sutures. We found low overall complication rates in both groups. The mean total active motion (TAM) for the dorsolateral group and post-middle group was 234.60°?±?22.63° and 221.08°?±?25.69°, respectively. There was a statistical significance between the two groups (P?=?0.037?AO mini titanium plate, movement in dorsolateral approach group was significantly higher than in post-middle approach group. Dorsolateral approach is an acceptable technique of incision for proximal phalangeal fractures. PMID:26730082

  12. DIFFRACTION-LIMITED VISIBLE LIGHT IMAGES OF ORION TRAPEZIUM CLUSTER WITH THE MAGELLAN ADAPTIVE SECONDARY ADAPTIVE OPTICS SYSTEM (MagAO)

    SciTech Connect

    Close, L. M.; Males, J. R.; Morzinski, K.; Kopon, D.; Follette, K.; Rodigas, T. J.; Hinz, P.; Wu, Y-L.; Puglisi, A.; Esposito, S.; Riccardi, A.; Pinna, E.; Xompero, M.; Briguglio, R.; Uomoto, A; Hare, T.

    2013-09-10

    We utilized the new high-order (250-378 mode) Magellan Adaptive Optics system (MagAO) to obtain very high spatial resolution observations in ''visible light'' with MagAO's VisAO CCD camera. In the good-median seeing conditions of Magellan (0.''5-0.''7), we find MagAO delivers individual short exposure images as good as 19 mas optical resolution. Due to telescope vibrations, long exposure (60 s) r' (0.63 {mu}m) images are slightly coarser at FWHM = 23-29 mas (Strehl {approx}28%) with bright (R < 9 mag) guide stars. These are the highest resolution filled-aperture images published to date. Images of the young ({approx}1 Myr) Orion Trapezium {theta}{sup 1} Ori A, B, and C cluster members were obtained with VisAO. In particular, the 32 mas binary {theta}{sup 1} Ori C{sub 1} C{sub 2} was easily resolved in non-interferometric images for the first time. The relative positions of the bright trapezium binary stars were measured with {approx}0.6-5 mas accuracy. We are now sensitive to relative proper motions of just {approx}0.2 mas yr{sup -1} ({approx}0.4 km s{sup -1} at 414 pc)-this is a {approx}2-10 Multiplication-Sign improvement in orbital velocity accuracy compared to previous efforts. For the first time, we see clear motion of the barycenter of {theta}{sup 1} Ori B{sub 2} B{sub 3} about {theta}{sup 1} Ori B{sub 1}. All five members of the {theta}{sup 1} Ori B system appear likely to be a gravitationally bound ''mini cluster'', but we find that not all the orbits can be both circular and co-planar. The lowest mass member of the {theta}{sup 1} Ori B system (B{sub 4}; mass {approx}0.2 M{sub Sun }) has a very clearly detected motion (at 4.1 {+-} 1.3 km s{sup -1}; correlation = 99.9%) w.r.t. B{sub 1}. Previous work has suggested that B{sub 4} and B{sub 3} are on long-term unstable orbits and will be ejected from this ''mini cluster''. However, our new ''baseline'' model of the {theta}{sup 1} Ori B system suggests a more hierarchical system than previously thought, and so the ejection of B{sub 4} may not occur for many orbits, and B{sub 3} may be stable against ejection in the long-term. This ''ejection'' process of the lowest mass member of a ''mini cluster'' could play a major role in the formation of low-mass stars and brown dwarfs.

  13. [Long-term results of compression-osteosynthesis with three AO-screws for spongiosa in fractures of the femur-neck (author's transl)].

    PubMed

    Penschuck, C; Zilch, H; Brenner, M

    1982-02-01

    Between 1969 and 1978 in 42 patients fractures of the femur-neck were treated with three AO-screws for spongiosa (screws with a short thread). Late results in these patients are reported. The interval between operation and follow-up was in average 90 months. In no case pseudarthrosis had developed; the rate of necrosis of the femur head was 23.8%. The method is suitable in selected cases of medial fractures of the femur-neck, type I and II, and in lateral fractures, preferably in younger patients. The results in fractures of type III according to Pauwels show, that in advanced age these fractures should be treated with a partial or total prosthesis, because the rate of necrosis of the femur-head cannot be lowered. PMID:7072000

  14. Levels, composition profiles and sources of polycyclic aromatic hydrocarbons in surface sediments from Nan'ao Island, a representative mariculture base in South China.

    PubMed

    Gu, Yang-Guang; Lin, Qin; Lu, Teng-Teng; Ke, Chang-Liang; Sun, Run-Xia; Du, Fei-Yan

    2013-10-15

    Levels, composition profiles and sources of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Nan'ao Island, one of the largest mariculture bases in South China were investigated. The total PAHs concentrations ranged from 265.49 to 951.27 ng/g (dry weight) with a mean of 515.90 ng/g, and seven possible carcinogenic PAHs accounted for 76.94% of total PAHs. Among various mariculture sections, the highest PAHs level was found in the large seaweed culture; while the lowest concentration was detected in the abandoned culture. The composition of PAHs was characterized by low molecular weight PAHs, and Phe Ant and Pyr were the dominant constituent. PAHs may be mainly originated from petroleum and combustion of biomass and coal. Risk assessments suggested that the probability of adverse effect was lower than 25% and PAHs exposure was moderately carcinogenic. PMID:23941805

  15. Anthogorgienes A-O, new guaiazulene-derived terpenoids from a Chinese gorgonian Anthogorgia species, and their antifouling and antibiotic activities.

    PubMed

    Chen, Dawei; Yu, Shanjiang; van Ofwegen, Leen; Proksch, Peter; Lin, Wenhan

    2012-01-11

    Fifteen new guaiazulene-based terpenoids designated anthogorgienes A-O (1-15) were isolated from a Chinese gorgonian Anthogorgia sp., together with eight known analogues (16-23). The structural patterns were classified into monomers, dimers, and trimers, which were supposed to be generated from a precursor guaiazulene and followed by side-chain and nucleus oxidation and oxidative rearrangement. The structures of new compounds were elucidated on the basis of extensive spectroscopic (IR, MS, and 1D and 2D NMR) data analysis. A possible biogenetic relationship of the isolated compounds was postulated. Some of the compounds showed potent antifouling activities against the larval settlement of barnacle Balanus amphitrite , whereas their antibiotic activities were also evaluated. PMID:22148226

  16. Near-IR bispectrum speckle interferometry, AO imaging polarimetry, and radiative transfer modeling of the proto-planetary nebula Frosty Leonis

    NASA Astrophysics Data System (ADS)

    Murakawa, K.; Ohnaka, K.; Driebe, T.; Hofmann, K.-H.; Oya, S.; Schertl, D.; Weigelt, G.

    2008-10-01

    Aims: We combined bispectrum speckle interferometry, adaptive optics (AO) imaging polarimetry, and radiative transfer modeling of polarized light to derive various physical properties of the proto-planetary nebula Frosty Leo. Methods: We performed bispectrum K'-band speckle interferometry and H- and K-band imaging polarimetry of Frosty Leo using the ESO 3.6 m telescope and the AO-equipped CIAO instrument of the 8 m Subaru telescope, respectively. Two-dimensional radiative transfer modeling was carried out in order to obtain a quantitative interpretation of our observations. Results: Our diffraction-limited speckle image shows distinct hourglass-shaped, point-symmetric bipolar lobes, an equatorial dust lane, and complex clumpy structures in the lobes. Our polarimetric data display a centro-symmetric polarization vector pattern with P~30-50% in the bipolar lobes and a polarization disk between them. The polarization images also reveal an elongated region with low polarization along a position angle of -45°. The observations suggest that this region has a low dust density and was carved out by a jet-like outflow. Our radiative transfer modeling can simultaneously explain the observed spectral energy distribution, the intensity distribution of the hourglass-shaped lobes, and our polarization images if we use two grain species with sizes of 0.005 ≤ a ≤ 2.0 μm at latitudes between -2° and +2°, and 0.005 ≤ a ≤ 0.7 μm in the bipolar lobes. Assuming a distance of 3 kpc, an expansion velocity of 25 km s-1, and a gas-to-dust mass ratio of 160, we derive a dust mass of the disk of 2.85×10-3 M⊙, a gas mass-loss rate of 8.97×10-3 M⊙ yr-1, and a total envelope mass of 4.23 M⊙.

  17. A Worldwide Analysis of the Reliability and Perceived Importance of an Injury to the Posterior Ligamentous Complex in AO Type A Fractures

    PubMed Central

    Schroeder, Gregory D.; Kepler, Christopher K.; Koerner, John D.; Oner, F. Cumhur; Fehlings, Michael G.; Aarabi, Bizhan; Dvorak, Marcel F.; Reinhold, Max; Kandziora, Frank; Bellabarba, Carlo; Chapman, Jens R.; Vialle, Luiz R.; Vaccaro, Alexander R.

    2015-01-01

    Study Design?Survey of spine surgeons. Objective?To determine the reliability with which international spine surgeons identify a posterior ligamentous complex (PLC) injury in a patient with a compression-type vertebral body fracture (type A). Methods?A survey was sent to all AOSpine members from the six AO regions of the world. The survey consisted of 10 cases of type A fractures (2 subtype A1, 2 subtype A2, 3 subtype A3, and 3 subtype A4 fractures) with appropriate imaging (plain radiographs, computed tomography, and/or magnetic resonance imaging), and the respondent was asked to identify fractures with a PLC disruption, as well as to indicate if the integrity of the PLC would affect their treatment recommendation. Results?Five hundred twenty-nine spine surgeons from all six AO regions of the world completed the survey. The overall interobserver reliability in determining the integrity of the PLC was slight (kappa?=?0.11). No substantial regional or experiential difference was identified in determining PLC integrity or its absence; however, a regional difference was identified (p?

  18. A new Liopropoma sea bass (Serranidae, Epinephelinae, Liopropomini) from deep reefs off Curaçao, southern Caribbean, with comments on depth distributions of western Atlantic liopropomins

    USGS Publications Warehouse

    Baldwin, Carole C.; Robertson, D. Ross

    2014-01-01

    Collecting reef-fish specimens using a manned submersible diving to 300 m off Curaçao, southern Caribbean, is resulting in the discovery of numerous new fish species. The new Liopropoma sea bass described here differs from other western Atlantic members of the genus in having VIII, 13 dorsal-fin rays; a moderately indented dorsal-fin margin; a yellow-orange stripe along the entire upper lip; a series of approximately 13 white, chevron-shaped markings on the ventral portion of the trunk; and a reddish-black blotch on the tip of the lower caudal-fin lobe. The new species, with predominantly yellow body and fins, closely resembles the other two “golden basses” found together with it at Curaçao: L. aberransand L. olneyi. It also shares morphological features with the other western Atlantic liopropomin genus,Bathyanthias. Preliminary phylogenetic data suggest that western Atlantic liopropomins, includingBathyanthias, are monophyletic with respect to Indo-Pacific Liopropoma, and that Bathyanthias is nested within Liopropoma, indicating a need for further study of the generic limits of Liopropoma. The phylogenetic data also suggest that western Atlantic liopropomins comprise three monophyletic clades that have overlapping depth distributions but different depth maxima (3–135 m, 30–150 m, 133–411 m). The new species has the deepest depth range (182–241 m) of any known western Atlantic Liopropomaspecies. Both allopatric and depth-mediated ecological speciation may have contributed to the evolution of western Atlantic Liopropomini.

  19. Characteristics of sodium guidestars created by the 50-watt FASOR and first closed-loop AO results at the Starfire Optical Range

    NASA Astrophysics Data System (ADS)

    Denman, Craig A.; Drummond, Jack D.; Eickhoff, Mark L.; Fugate, Robert Q.; Hillman, Paul D.; Novotny, Steven J.; Telle, John M.

    2006-06-01

    A computer-automated cw sodium guidestar FASOR (Frequency Addition Source of Optical Radiation) producing a single frequency 589-nm beam with up to 50 W for mesospheric beacon generation has been integrated with the 3.5-m telescope at the Starfire Optical Range, Kirtland AFB, New Mexico. Radiance tests have produced a peak guidestar V I magnitude = 5.1 (~7000 photons/s/cm2 at zenith) for 30 W of circularly polarized pump power in November 2005. Estimated theoretical maximum guidestar radiance is about 3 times greater than measured values indicating saturation due to atoms possibly becoming trapped in F'=1 and/or atomic recoil. From sky tests over 3.5 years, we have tracked the annual variation of the sodium column density by measuring the return flux as a function of fasor power and determining the slope at zero power. The maximum occurs on October 30 and the minimum on May 30, with corresponding predicted returns of 8000 (V I = 4.8) and 3000 (V I = 5.8) ph/s/cm2 with 50 W of fasor power and circular polarization. The effect of the Earth's magnetic field on the radiance of the sodium laser guidestar (LGS) from various azimuths and elevations has been measured. The peak return flux over our observatory occurs at [az=198 °; el=+71 °], compared with the direction of the magnetic field lines at [190 °; +62 °], and it can vary by a factor of 3 over the sky above el = 30 °. First results for non-optimized sodium LGS adaptive optics (AO) closed-loop operation have been obtained using binary stars. Strehl ratios of 0.03 have been measured at 850 nm and a 0.14 arc second binary star has been resolved during first closed loop observations. Guidestar characteristics, including radiance, size, and Rayleigh backscatter, the sodium LGS wavefront sensor (WFS) AO system, and recent closed-loop results on binary stars are presented.

  20. Reconstruction of High Dynamic Range Images: Simulations of LBT Observations of a Stellar Jet, a Pathfinder Study for Future AO-Assisted Giant Telescopes

    NASA Astrophysics Data System (ADS)

    La Camera, A.; Antoniucci, S.; Bertero, M.; Boccacci, P.; Lorenzetti, D.; Nisini, B.; Arcidiacono, C.

    2014-02-01

    We present simulated Large Binocular Telescope (LBT) infrared narrow-band observations of a star-jet system, in conjunction with improved and optimized deconvolution and image reconstruction algorithms, considering two cases of interest: single-dish direct imaging with an AO-assisted camera and imaging through a Fizeau interferometer that combines the beams of the two mirrors of LBT. We aim at understanding what accuracy can be obtained with the use of present AO-assisted large telescopes (such as LBT) and what improvements an interferometric instrument (such as LINC-NIRVANA) will be able to provide. The proposed deconvolution method is based on the target decomposition as a sum of a point source (the star) and an extended source (the jet). By assuming Poisson noise we add to the negative logarithm of the likelihood a regularization term enforcing smoothness of the jet component. Finally, we use a Richardson-Lucy-like method for the minimization of this function. This approach is an improvement of a method proposed by Lucy in 1994 for accurate photometric restoration of HST images and called two channel photometric restoration. We denote the new method as the multi-component Richardson-Lucy (MC-RL) method. The analysis of the reconstructed objects shows that the MC-RL method applied to the interferometric observations allows us to evaluate the width and the spatial intensity profile of the jet down to 20 mas with an accuracy better than about 20% in the best case of a central star fainter than 10 mag. These limits allow us to obtain a very good reconstruction of the jet acceleration region very close to the exciting source, which would provide fundamental scientific information on the jet collimation degree and eventually on its launching mechanism. As concerns the proposed MC-RL method, it demonstrates a good performance in the reconstruction of images with a very high dynamic range. It can be improved in several directions, by increasing both its efficiency, thanks to recently proposed acceleration techniques, and its accuracy by means of more sophisticated regularization terms. We are also planning to apply the method to simulated observations of upcoming super giant earth-based telescopes.

  1. A Hybrid Numerical Method for Turbulent Mixing Layers. Degree awarded by Case Western Reserve Univ.

    NASA Technical Reports Server (NTRS)

    Georgiadis, Nicholas J.

    2001-01-01

    A hybrid method has been developed for simulations of compressible turbulent mixing layers. Such mixing layers dominate the flows in exhaust systems of modern day aircraft and also those of hypersonic vehicles currently under development. The method configurations in which a dominant structural feature provides an unsteady mechanism to drive the turbulent development in the mixing layer. The hybrid method uses a Reynolds-averaged Navier-Stokes (RANS) procedure to calculate wall bounded regions entering a mixing section, and a Large Eddy Simulation (LES) procedure to calculate the mixing dominated regions. A numerical technique was developed to enable the use of the hybrid RANS-LES method on stretched, non-Cartesian grids. Closure for the RANS equations was obtained using the Cebeci-Smith algebraic turbulence model in conjunction with the wall-function approach of Ota and Goldberg. The wall-function approach enabled a continuous computational grid from the RANS regions to the LES region. The LES equations were closed using the Smagorinsky subgrid scale model. The hybrid RANS-LES method is applied to a benchmark compressible mixing layer experiment. Preliminary two dimensional calculations are used to investigate the effects of axial grid density and boundary conditions. Vortex shedding from the base region of a splitter plate separating the upstream flows was observed to eventually transition to turbulence. The location of the transition, however, was much further downstream than indicated by experiments. Actual LES calculations, performed in three spatial directions, also indicated vortex shedding, but the transition to turbulence was found to occur much closer to the beginning of the mixing section. which is in agreement with experimental observations. These calculations demonstrated that LES simulations must be performed in three dimensions. Comparisons of time-averaged axial velocities and turbulence intensities indicated reasonable agreement with experimental data.

  2. PLUM: Parallel Load Balancing for Unstructured Adaptive Meshes. Degree awarded by Colorado Univ.

    NASA Technical Reports Server (NTRS)

    Oliker, Leonid

    1998-01-01

    Dynamic mesh adaption on unstructured grids is a powerful tool for computing large-scale problems that require grid modifications to efficiently resolve solution features. By locally refining and coarsening the mesh to capture physical phenomena of interest, such procedures make standard computational methods more cost effective. Unfortunately, an efficient parallel implementation of these adaptive methods is rather difficult to achieve, primarily due to the load imbalance created by the dynamically-changing nonuniform grid. This requires significant communication at runtime, leading to idle processors and adversely affecting the total execution time. Nonetheless, it is generally thought that unstructured adaptive- grid techniques will constitute a significant fraction of future high-performance supercomputing. Various dynamic load balancing methods have been reported to date; however, most of them either lack a global view of loads across processors or do not apply their techniques to realistic large-scale applications.

  3. Stability of large horizontal-axis axisymmetric wind turbines. Ph.D. Thesis - Delaware Univ.

    NASA Technical Reports Server (NTRS)

    Hirschbein, M. S.; Young, M. I.

    1980-01-01

    The stability of large horizontal axis, axi-symmetric, power producing wind turbines was examined. The analytical model used included the dynamic coupling of the rotor, tower and power generating system. The aerodynamic loading was derived from blade element theory. Each rotor blade was permitted tow principal elastic bending degrees of freedom, one degree of freedom in torsion and controlled pitch as a rigid body. The rotor hub was mounted in a rigid nacelle which may yaw freely or in a controlled manner. The tower can bend in two principal directions and may twist. Also, the rotor speed can vary and may induce perturbation reactions within the power generating equipment. Stability was determined by the eigenvalues of a set of linearized constant coefficient differential equations. All results presented are based on a 3 bladed, 300 ft. diameter, 2.5 megawatt wind turbine. Some of the parameters varied were; wind speed, rotor speed structural stiffness and damping, the effective stiffness and damping of the power generating system and the principal bending directions of the rotor blades. Unstable or weakly stable behavior can be caused by aerodynamic forces due to motion of the rotor blades and tower in the plane of rotation or by mechanical coupling between the rotor system and the tower.

  4. Nitridation of silicon. M.S. Thesis Case Western Reserve Univ.

    NASA Technical Reports Server (NTRS)

    Shaw, N. J.

    1981-01-01

    Silicon powders with three levels of impurities, principally Fe, were sintered in He or H2. Non-densifying mechanisms of material transport were dominant in all cases. High purity Si showed coarsening in He while particle growth was suppressed in H2. Lower purity powder coarsened in both He and H2. The same three Si powders and Si /111/ single crystal wafers were nitrided in both N2 and N2/H2 atmospheres. Hydrogen increased the degree of nitridation of all three powders and the alpha/beta ratio of the lower purity powder. Some Si3N4 whiskers and open channels through the surface nitride layer were observed in the presence of Fe, correlating with the nitridation-enhancing effects of Fe. Thermodynamic calculations showed that when SiO2 is present on the Si, addition of H2 to the nitriding atmosphere decreases the amount of SiO2 and increases the partial pressure of Si-containing vapor species, that is, Si and SiO. Large amounts of NH3 and SiH4 were also predicted to form.

  5. [Electron transfer, ionization, and excitation in atomic collisions]. [Pennsylvania State Univ

    SciTech Connect

    Not Available

    1992-01-01

    Fundamental processes of electron transfer, ionization, and excitation in ion-atom and ion-ion collisions are studied. Attention is focussed on one- and two-electron systems and, more recently, quasi-one-electron systems whose electron-target-ion core can be accurately modeled by one-electron potentials. The basic computational approaches can then be taken with few, if any, approximations, and the underlying collisional mechanisms can be more clearly revealed. At intermediate collision energies (e.g., proton energies for p-He[sup +] collisions on the order of 100 kilo-electron volts), many electronic states are strongly coupled during the collision, a coupled-state approach, such as a coupled-Sturmian-pseudostate approach, is appropriate. At higher collision energies (million electron-volt energies) the coupling is weaker with, however, many more states being coupled together, so that high-order perturbation theory is essential.

  6. Gravitational radiation theory. M.A. Thesis - Rice Univ.; [survey of current research

    NASA Technical Reports Server (NTRS)

    Wilson, T. L.

    1973-01-01

    A survey is presented of current research in the theory of gravitational radiation. The mathematical structure of gravitational radiation is stressed. Furthermore, the radiation problem is treated independently from other problems in gravitation. The development proceeds candidly through three points of view - scalar, rector, and tensor radiation theory - and the corresponding results are stated.

  7. Education Research and Teaching in Astrophysical & Planetary Sciences at the Univ. of Colorado

    NASA Astrophysics Data System (ADS)

    Duncan, D. K.; Arthurs, L.

    2009-12-01

    The Department of Astrophysical and Planetary sciences at the University of Colorado has increasingly been incorporating research-based science education practices. The Colorado physics education research (PER) group is now one of the largest and most productive in the nation. It includes the work of Nobel laureate Carl Wieman's Science Education Initiative. Discipline-based education researchers in physics, astronomy, geology, and other departments meet weekly. Like physics, essentially all large courses in Astrophysical and Planetary Sciences are now taught using peer instruction and "clickers." Approximately 17,000 clickers are in use at CU. A new diagnostic instrument whose subject is (modern) solar system astronomy has been developed and is available for testing. The first-ever departmental Ph.D. in astronomy education research (AER) is under way. A curriculum that encourages students to use more scientific thinking in everyday life and to distinguish good science from bad has been successfully tested. It can be used as part of any introductory geology or astronomy course. Two faculty members are conducting AER, supported by NSF Grant No. 0715517, a CCLI Phase III Grant for the Collaboration of Astronomy Teaching Scholars (CATS) Program. Neither of these two faculty members are in tenure-track lines.

  8. General Theory of the Double Fed Synchronous Machine. Ph.D. Thesis - Swiss Technological Univ., 1950

    NASA Technical Reports Server (NTRS)

    El-Magrabi, M. G.

    1982-01-01

    Motor and generator operation of a double-fed synchronous machine were studied and physically and mathematically treated. Experiments with different connections, voltages, etc. were carried out. It was concluded that a certain degree of asymmetry is necessary for the best utilization of the machine.

  9. Liquid jet impingement normal to a disk in zero gravity. Ph.D. Thesis - Toledo Univ.

    NASA Technical Reports Server (NTRS)

    Labus, T. L.

    1976-01-01

    An experimental and analytical investigation was conducted to determine the free surface shapes of circular liquid jets impinging normal to sharp-edged disks under both normal and zero gravity conditions. An order of magnitude analysis was conducted indicating regions where viscous forces were not significant when computing free surface shapes. The demarcation between the viscous and inviscid region was found to depend upon the flow Reynolds number and the ratio between the jet and disk radius.

  10. Experimental investigations in particle physics at intermediate energies. [Physics Dept. , Temple Univ

    SciTech Connect

    Auerbach, L.B.; Highland, V.L.; McFarlane, K.W.; Kettell, S.H.

    1992-07-12

    The major emphasis of this project continues to be on fundamental symmetries and parameters of the Standard Model. A test of a quark model prediction was also done. The projects in the current period have been the following: LSND, a neutrino oscillation experiment at LAMPF; E791, a search for the decays K{sub L}{sup 0} {yields} {mu}e and K{sub L}{sup 0} {yields} ee; E871, tests and preparations for an upgrade proposal; and E888, a search for the H dibaryon. The LSND (Large Scintillator Neutrino Detector) is under construction at this time. Progress in the construction schedule has been accelerated with the expectation of being ready to accept beam in March 1993. The automated system for testing photomultiplier tubes is in full production, and should be able to certify a fun complement of tubes for installation by October 1992. Results of an earlier LAMPF experiment, E764, on the interaction of muon neutrinos with carbon nuclei have been submitted for publication. A thorough 'blind' analysis of the E791 data set has just been brought to completion. Final results for the upper limits (90% C.L.) on the branching ratios for the decays K{sub L}{sup 0} {yields} {mu}e and K{sub L}{sup 0} {yields} ee are 3.3 {times} 10{sup {minus}11} and 4.1 {times} 10{sup {minus}11}, respectively. The final result for the branching ratio for K{sub L}{sup 0} {yields} {mu}{mu} from all the data (720 events) is (7.0 {plus minus} 0.4 {plus minus} 0.2) {times} 10{sup {minus}9}. The potential of the E791 detector for rare K decays has reached its limit. Before disassembly it was used to mount a search (E888) for a possible long-lived six-quark state, the H. At the same time studies have been made of an upgraded version of the experiment (E871) that will make use of a portion of the existing apparatus.

  11. Vehicle integration effects on hypersonic waveriders. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Cockrell, Charles Edward, Jr.

    1994-01-01

    The integration of a class of hypersonic high-lift configurations known as waveriders into hypersonic cruise vehicles was evaluated. Waveriders offer advantages in aerodynamic performance and propulsion/airframe integration (PAI) characteristics over conventional hypersonic shapes. A wind-tunnel model was developed which integrates realistic vehicle components with two waverider shapes, referred to as the 'straight-wing' and 'cranked-wing' shapes. Both shapes were conical-flow-derived waveriders at a design Mach number of 4.0. The cranked-wing shape was designed to provide advantages in subsonic performance and directional stability over conventional waveriders. Experimental data and limited computational fluid dynamics (CFD) predictions were obtained over a Mach number range of 2.3 to 4.63 at a Reynolds number of 2.0x10(exp 6) per foot. The CFD predictions and flow visualization data confirmed the shock attachment characteristics of the baseline waverider shapes and illustrated the waverider flow-field properties. Both CFD predictions and experimental data showed that no significant performance degradations occur at off-design Mach numbers for the waverider shapes and the integrated configurations. The experimental data showed that the effects of adding a realistic canopy were minimal. The effects of adding engine components were to increase the drag and thus degrade the aerodynamic performance of the configuration. A significant degradation in aerodynamic performance was observed when 0 degree control surfaces were added to close the blunt base of the waverider to a sharp trailing edge. A comparison of the fully-integrated waverider models to the baseline shapes showed that the performance was significantly degraded when all of the components were added to the waveriders. The fully-integrated configurations studied here do not offer significant performance advantages over conventional hypersonic vehicles, but still offer advantages in air-breathing propulsion integration. Additionally, areas are identified in this study where improvements could be made to enhance the performance. Both fully-integrated configurations are longitudinally unstable over the Mach number range studied for unpowered conditions. The cranked-wing fully-integrated configuration provided significantly better lateral-directional stability characteristics than the straight-wing configuration.

  12. Braided Carbon Fiber Rope Flow Characteristics. Degree awarded by Utah Univ.

    NASA Technical Reports Server (NTRS)

    Heman, J. R. C.; McCool, A. (Technical Monitor)

    2000-01-01

    I am submitting the following technical subject for consideration as a thesis topic for the master degree: The reusable solid rocket motor (RSRM) nozzle internal joints are being evaluated for the incorporation of a carbon fiber rope (CFR) as a thermal barrier. The CFR is approximately 0.260 in. diameter and is composed of approximately 12,000 carbon fibers, woven in ten sheaths or layers. The CFR is manufactured by a sub-tier vendor and subsequently several of its manufacturing details are proprietary to that vendor. The CFR design intent is to prevent hot motor combustion products and slag from intruding into the joint scaling area while still approaching a vented joint design to avoid the detriments of gas jet impingement. As a member of the Heat Transfer section at Thiokol Propulsion, two main goals exist as part of this NASA funded design effort: (1) development of flow model through the CFR and (2) development of a heat transfer model through the CFR. While both models are needed and most probably interrelated, the gas flow model is being targeted as the subject matter. Essentially, the topic would be "Modeling of Gas Flow through a Braided Carbon Fiber Rope". An AIAA journal or conference paper is being considered through Thiokol/NASA as well. A sub-scale CFR flow test fixture was designed to simulate the relative levels of CFR compression. The test fixture provides the means to measure gas mass flow rate upstream of the CFR and the pressure and temperature both upstream and downstream of the CFR. The test fixture was designed to eliminate the possibility of dynamic gapping at the CFR location and provide minimal flow resistance to ambient for gases exiting the rope. The data collected in the experiment will be evaluated to define a permeability/flow resistance model. Two possibilities exist for the flow characteristics through the CFR from choked flow to strictly friction driven. A test matrix for evaluating the CFR has been compiled, which addresses both of these characteristics. The range of pressures to be tested covers a relatively low delta pressure where non-choked flow is impossible, while the high pressure shown is dictated by the RSRM joint operating pressure where choking is possible. The test matrix, was also designed for a range of rope compressions or test fixture gaps ranging from 0.025" to 0.070". These gaps are controlled by the range of RSRM full-scale hardware joint gaps that will be expected by virtue of the joint design.

  13. Theory of elementary particles and accelerator theory: Task C: Experimental high energy physics. [Univ. of Oregon

    SciTech Connect

    Brau, J.E.

    1992-01-01

    The experimental high energy physics group at the University of Oregon broadened its effort during the past year. The SLD effort extends from maintaining and operating the SLD luminosity monitor which was built at Oregon, to significant responsibility in physics analysis, such as event selection and background analysis for the left-right asymmetry measurement. The OPAL work focussed on the luminosity monitor upgrade to a silicon-tungsten calorimeter. Building on the work done at Oregon for SLD, the tungsten for this upgrade was machined by the Oregon shops and shipped to CERN for assembly. The Oregon GEM effort now concentrates on tracking, specifically silicon tracking. Oregon also has developed a silicon strip preradiator prototype, and tested it in a Brookhaven beam.

  14. Analysis of objects in binary images. M.S. Thesis - Old Dominion Univ.

    NASA Technical Reports Server (NTRS)

    Leonard, Desiree M.

    1991-01-01

    Digital image processing techniques are typically used to produce improved digital images through the application of successive enhancement techniques to a given image or to generate quantitative data about the objects within that image. In support of and to assist researchers in a wide range of disciplines, e.g., interferometry, heavy rain effects on aerodynamics, and structure recognition research, it is often desirable to count objects in an image and compute their geometric properties. Therefore, an image analysis application package, focusing on a subset of image analysis techniques used for object recognition in binary images, was developed. This report describes the techniques and algorithms utilized in three main phases of the application and are categorized as: image segmentation, object recognition, and quantitative analysis. Appendices provide supplemental formulas for the algorithms employed as well as examples and results from the various image segmentation techniques and the object recognition algorithm implemented.

  15. Technical progress report, November 1, 1979-October 31, 1980. Report NPL-865. [Univ. of Colorado

    SciTech Connect

    Not Available

    1980-11-01

    Work carried out at the Nuclear Physics Laboratory of the University of Colorado from November 1, 1979 through October 31, 1980 is summarized. Emphasis was on light ion reaction studies with the AVF cyclotron. The high resolution magnetic spectrometer has allowed studies of nucleon transfer, scattering, and charge exchange reactions throughout the periodic table. More experiments have been run with solid state counters this year than has been the case recently, as a broad range spectra of the light nuclei where only moderate resolution is demanded were examined. Several of these experiments were undertaken for more detailed studies of excitations seen with higher energy probes. Multiple coincidence measurements with neutron and gamma-ray counters have opened a new program in pre-equilibrium reactions and provided a new signature for the study of neutron-deficient final nuclei. The neutron time of flight program has expanded to higher excitation and to use of the (d,n) and (..cap alpha..,n) direct nucleon transfer reactions. Three important experiments were completed at the EPICS pion scattering facility at LAMPF, and other low energy pion scattering data were obtained at TRIUMF. Several (p,d) runs at high energies were accomplished, some with polarized beams at TRIUMF. High-lying structures in medium mass nuclei were studied by the (p,n) reaction at Indiana. Interest in the use of polarized beams has been prompted by the theoretical successes in this area. This interest has led to the study of one- and two-nucleon transfer reactions on a range of nuclei at the Los Alamos tandem and at IUCF.

  16. D'un univers culturel a l'autre (From One Cultural Universe to Another).

    ERIC Educational Resources Information Center

    Molinie, Muriel

    1988-01-01

    It is possible to develop an intermediate cultural system much like the interlanguage developed at the intermediate stage by a language learner. Techniques used by one teacher of French are described and discussed. (MSE)

  17. L'univers familier de l'enfant africain (The Familiar Surroundings of the African Child).

    ERIC Educational Resources Information Center

    Njock, Pierre-Emmanuel

    This study on the African child had three objectives: (1) to become familiar with the environment of the African child, (2) to investigate the vocabulary to which the child is exposed at home and at school, and (3) to compare the vocabulary of the native language with that of the school. The first part of the study constituted a linguistic study…

  18. A Tri-Univer-City Project for Teachers in Inner-City Schools.

    ERIC Educational Resources Information Center

    Winsand, Jean E.

    Recognizing the problems of reading instruction as a major challenge in education, Educational Professions Development Act (EPDA) Institutes of recent years have funded several programs to develop new methods and materials for teaching in inner-city schools. The project reported here is an EPDA Institute for teachers of disadvantaged children in…

  19. Studies of nuclei using radioactive beams. [Space Astronomy Lab. , Univ. of Florida, Gainesville, Florida

    SciTech Connect

    Piercey, R.B.

    1989-07-01

    The 12 month period from May 1988 to July 1989 represents the first full year of our 18 month pilot program in nuclear structure research. In this period, research was initiated to develop a capability for radioactive secondary beams at Argonne National Laboratory using the Atlas and the new Fragment Mass Analyzer (FMA), which is currently under construction. Two major new detector facilities are currently in the final stages of design and testing. The Large-Area, Scintillator Telescope (LAST) detector is fully operational and will be shipped to Argonne National Laboratory in August for fit-tests and in-beam calibrations. The first segments of a new sixteen-segment neutron multiplicity detector have been built and tested. The remaining segments are currently being constructed. Research was continued in the areas of (1) Coulomb excitation studies of rare earth and actinide nuclei; (2) In-beam, gamma-ray spectroscopy of nuclei in the mass 100 region, and (3) Advanced detector design. Several journal articles and abstracts were published or submitted for publication in the reporting period, and others are currently in preparation. Three graduate students participated in the program, one from the University of Florida and two from the Royal Institute of Technology, Stockholm, Sweden.

  20. Semiempirical studies of atomic structure. [Dept. of Physics and Astronomy, Univ. of Toledo

    SciTech Connect

    Curtis, L.J.

    1992-01-01

    The energy level structure, transition probabilities, and general spectroscopic properties of highly ionized many-electron systems are studied through the combined use of sensitive semiempirical data systematizations, selected precision experimental measurements, and specialized theoretical computations. Measurements are made primarily through the use of fast ion beam excitation methods, which are combined with available data from laser-and tokamak-produced plasmas, astrophysical sources, and conventional light sources. The experimental studies are strengthened through large-scale ab initio calculations. Typical examples are the following: lifetime measurements in the neon isoelectronic sequence; multiplexed decay curve measurements of Li-like Si XII; and isoelectronic specification of intershell resonance and intercombination decay rates using measured transition probabilities and spectroscopically determined singlet-mixing amplitudes.

  1. Free-Swinging Failure Tolerance for Robotic Manipulators. Degree awarded by Purdue Univ.

    NASA Technical Reports Server (NTRS)

    English, James

    1997-01-01

    Under this GSRP fellowship, software-based failure-tolerance techniques were developed for robotic manipulators. The focus was on failures characterized by the loss of actuator torque at a joint, called free-swinging failures. The research results spanned many aspects of the free-swinging failure-tolerance problem, from preparing for an expected failure to discovery of postfailure capabilities to establishing efficient methods to realize those capabilities. Developed algorithms were verified using computer-based dynamic simulations, and these were further verified using hardware experiments at Johnson Space Center.

  2. Research in elementary particle physics. [Dept. of Physics and Astronomy, Louisiana State Univ,. Baton Rouge, Louisiana

    SciTech Connect

    Chan, L.H; Haymaker, R.; Imlay, R.; McNeil, R.; Metcalf, W.; Svoboda, R.

    1992-01-01

    Theoretical work on effective action expansion on an effective low; energy theory of hadron, dynamical symmetry breaking, and lattice gauge theories is described. The high-energy experimental group at Louisiana State University has analyzed data on a neutrino oscillation experiment at LAMPF. Preparations for the LSND neutrino experiment have stated. IMB data have also been analyzed. On the ZEUS electron n-proton colliding bean experiment, the production of the barrel calorimeter has been completed. Several modules of the calorimeter have been tested at Fermilab, and preparations for data taking are underway.

  3. Flight-management strategies for escape from microburst encounters. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Hinton, David A.

    1988-01-01

    An effort is underway by NASA, FAA, and industry to reduce the threat of convective microburst wind shear phenomena to aircraft. The goal is to develop and test a candidate set of strategies for recovery from inadvertent microburst encounters during takeoff. Candidate strategies were developed and evaluated using a fast-time simulation consisting of a simple point-mass performance model of a transport-category airplane and an analytical microburst model. The results indicate that the recovery strategy characteristics that best utilize available airplane energy include an initial reduction in pitch attitude to reduce the climb rate, followed by an increase in pitch up to the stick shaker angle of attack. The stick shaker angle of attack should be reached just as the airplane is exiting the microburst. The shallowest angle of climb necessary for obstacle clearance should be used. If the altitude is higher than necessary, an intentional descent to reduce the airspeed deceleration should be used. Of the strategies tested, two flight-path-angle based strategies had the highest recovery altitudes and the least sensitivity to variations in the encounter scenarios.

  4. Curved descending landing approach guidance and control. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Crawford, D. J.

    1974-01-01

    Linear optimal regulator theory is applied to a nonlinear simulation of a transport aircraft performing a helical landing approach. A closed form expression for the quasi-steady nominal flight path is presented along with the method for determining the corresponding constant nominal control inputs. The Jacobian matrices and the weighting matrices in the cost functional are time varying. A method of solving for the optimal feedback gains is reviewed. The control system is tested on several alternative landing approaches using both three and six degree flight path angles. On each landing approach, the aircraft was subjected to large random initial state errors and to randomly directed crosswinds. The system was also tested for sensitivity to changes in the parameters of the aircraft and of the atmosphere. Performance of the optimal controller on all the three degree approaches was very good, and the control system proved to be reasonably insensitive to parametric uncertainties.

  5. An experimental investigation of a supersonic vortical flow. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Levey, Brian S.

    1991-01-01

    Although much research has been done on subsonic vortical flow, the current understanding of these flows remains limited. The effect is characterized of adding swirl to a supersonic jet. The motive is to study the enhancement of supersonic mixing in order to provide more efficient fuel injectors for supersonic combustion (scramjet) engines. The vortical flow was created by tangential injection into a swirl chamber ahead of a converging and/or diverging nozzle. The amount of swirl was varied by changing the number of tangential injection holes and with the removal of the end piece, the jet could be run without swirl. Shadowgraphy, conventional schlieren, and focusing schlieren were used to obtain a qualitative understanding of the jet flow structure. It was determined that an increase in swirl produced an increase in the shear layer growth. Pressure and temperature probes were used to obtain more flow data. The probe data compared favorably with the theoretical calculations, except in the viscous core where viscous effects were not considered negligible. These results verified that a supersonic vortical flow was being created with a maximum helix angle of 33 degs.

  6. Condensed matter research using the UCSB FEL. [Univ. of California, Santa Barbara Free Electron Laser project

    SciTech Connect

    Not Available

    1992-01-01

    The University of California, Santa Barbara (UCSB) Free Electron Laser (FEL) project was initiated in 1981 to test the idea of using an electrostatic accelerator in a recirculating beam mode to produce high-power, continuously tunable, coherent far infrared radiation. The development and application of this device to condensed matter research are briefly recounted. Emphasis was on semiconductor research and two-photon experiments. (RWR)

  7. Relativistic heavy ion research. [Dept. of Physics and Astronomy, Wayne State Univ. , Detroit, Michigan

    SciTech Connect

    Not Available

    1992-01-01

    Experimental work is reported on the following topics: transverse energy production in 10.7-GeV/c/u Au on Au collisions; first results on delta ray production and charged particle multiplicities with the Au beam at 10.7 GeV/c/A; preliminary studies on the feasibility of flow measurement with the E814 participant calorimeter; preliminary results from the E877 telescope; and low-p[sub t] baryon distribution in Si+Al, Pb collisions at the AGS. Then the status of the Hadronic Calorimeter project of AGS Experiment E864 (ECOS--Exotic Composite Object Spectrometer) is reviewed. Next, the same is done for work of the STAR RHIC collaboration (Silicon Vertex Tracker (SVT) project evolution and development in FY92, SVT software results from 1992, SVT instrumentation, FY93 SVT pion test beam). The instrumentation section deals with the design and installation of a target rapidity telescope for BNL experiment 814/877 and a repair scheme for the E814/E877 participant calorimeter. Finally, the theory part addresses bosonic kinetics: thermalization of mesons and the pion p[sub perpendicular] spectrum in ultrarelativistic heavy-ion collisions and non-equilibrium properties of hadronic mixtures.

  8. A new approach to telemetry data processing. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Broglio, C. J.

    1973-01-01

    An approach for a preprocessing system for telemetry data processing was developed. The philosophy of the approach is the development of a preprocessing system to interface with the main processor and relieve it of the burden of stripping information from a telemetry data stream. To accomplish this task, a telemetry preprocessing language was developed. Also, a hardware device for implementing the operation of this language was designed using a cellular logic module concept. In the development of the hardware device and the cellular logic module, a distributed form of control was implemented. This is accomplished by a technique of one-to-one intermodule communications and a set of privileged communication operations. By transferring this control state from module to module, the control function is dispersed through the system. A compiler for translating the preprocessing language statements into an operations table for the hardware device was also developed. Finally, to complete the system design and verify it, a simulator for the collular logic module was written using the APL/360 system.

  9. Experimental and Theoretical Studies of Interstellar Grains. Ph.D. Thesis - Maryland Univ., College Park, 1982

    NASA Technical Reports Server (NTRS)

    Nuth, J. A., III

    1981-01-01

    Steady state vibrational populations of SiO and CO in dilute black body radiation fields were calculated as a function of total pressure, kinetic temperature and chemical composition of the gas. Approximate calculations for polyatomic molecules are presented. Vibrational disequilibrium becomes increasingly significant as total pressure and radiation density decrease. Many regions of postulated grain formation are found to be far from thermal equilibrium before the onset of nucleation. Calculations based upon classical nucleation theory or equilibrium thermodynamics are expected to be of dubious value in such regions. Laboratory measurements of the extinction of small iron and magnetite grains were made from 195 nm to 830 nm and found to be consistent with predictions based upon published optical constants. This implies that small iron particles are not responsible for the 220 nm interstellar extinction features. Additional measurements are discussed.

  10. Characterization of the multifragment decay channel in highly excited nuclei. [Indiana Univ. , Bloomington, Indiana

    SciTech Connect

    de Souza, R.T.

    1992-10-01

    Characteristics of multifragment decay in heavy-ion induced reactions at intermediate energies are explored. Evolution of the timescale for emission of intermediate mass fragments (IMF: 3[le]Z[le]20) is investigated. Fragments associated with central collisions in the reactions [sup 36]Ar + [sup 197]Au at E/A = 50, 80, and 110 MeV are emitted on an extremely fast timescale, [tau] [le] 75 fm/c, comparable to the transit time of the projectile past the target nucleus. With increasing incident energy, mean fragment emission times decrease, consistent with statistical decay from highly excited systems or fast dynamical processes. To examine the importance of expansion effects in multifragmentation, the transverse kinetic energy of fragments was investigated. Evidence for expansion effects in the system [sup 36]Ar + [sup 197]Au at E/A = 50, 80, and 110 MeV was indicated by the charge dependence of the mean isotropic kinetic energy. At the highest incident energy the data suggest the onset of volume emission. Construction and performance of low-threshold high-resolution detector telescopes is discussed. Three-body Coulomb trajectory calculations are being used to probe kinematical correlations associated with neck emission of IMFs during fission. Initial design and testing of position sensitive parallel plate avalanche counters for upcoming ternary fission experiments is discussed.

  11. A Marriage of Minds: James R. Jacobs & Shinjoung Yeo Univ. of California-San Diego

    ERIC Educational Resources Information Center

    Library Journal, 2005

    2005-01-01

    Their personalities and backgrounds are very different, but James R. Jacobs and Shinjoung Yeo are passionate about the same causes: librarianship, open government, and empowerment through information. They balance each other. Yeo is focused, realistic, critical, and an excellent researcher. Her superhero alter ego is Wet Blanket Woman, able to…

  12. Topics in Astrophysical X-Ray and Gamma Ray Spectroscopy. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Bussard, R. W.

    1978-01-01

    A number of topics relating to astrophysical observations that have already been made or are currently planned of spectral features, mostly emission lines, in the X-ray and gamma ray region of the electromagnetic spectrum are investigated. These topics include: the production of characteristic X-ray and gamma ray lines by nonthermal ions, spectral features induced by processes occurring in strong magnetic fields, and the positron annihilation line at 0.5 MeV. The rate of X-ray production at 6.8 keV by the 2p to 1s transition in fast hydrogen- and helium-like iron ions, following both electron capture to excited levels and collisional excitation is calculated. The cross section for electron-ion Coulomb collisions in strong fields is also calculated.

  13. Theoretical particle physics. Progress report, December 1, 1079-November 30, 1980. [Physics Dept. , Indiana Univ

    SciTech Connect

    Hendry, A.W.; Lichtenberg, D.B.; Weingarten, D.H.

    1980-08-01

    Work during the past year ranged from phenomenological studies of various quark systems to applications of quantum chromodynamics and lattice gauge theories. On the phenomenological side for mesons, studies of the charmonium and bottomonium families as well as the spectrum of states containing a single b-quark continued. As a result of some improved measurements, the topic of baryon magnetic moments was reconsidered. At the same time the properties of highly excited 3-quark systems were considered in view of the recent confirmation of resonances with spins up through 21/2. Quark configurations allowing for N colors were also studied, where N was varied. In the area of gauge field theories on a lattice, several interesting connections between gauge theories and interacting string models were found. Monte Carlo techniques were developed to study the problem of quark confinement, by means of a lattice version of QCD. Lastly, a new approach to the problem of quantizing gravity was started.

  14. Generalized Reliability Methodology Applied to Brittle Anisotropic Single Crystals. Degree awarded by Washington Univ., 1999

    NASA Technical Reports Server (NTRS)

    Salem, Jonathan A.

    2002-01-01

    A generalized reliability model was developed for use in the design of structural components made from brittle, homogeneous anisotropic materials such as single crystals. The model is based on the Weibull distribution and incorporates a variable strength distribution and any equivalent stress failure criteria. In addition to the reliability model, an energy based failure criterion for elastically anisotropic materials was formulated. The model is different from typical Weibull-based models in that it accounts for strength anisotropy arising from fracture toughness anisotropy and thereby allows for strength and reliability predictions of brittle, anisotropic single crystals subjected to multiaxial stresses. The model is also applicable to elastically isotropic materials exhibiting strength anisotropy due to an anisotropic distribution of flaws. In order to develop and experimentally verify the model, the uniaxial and biaxial strengths of a single crystal nickel aluminide were measured. The uniaxial strengths of the <100> and <110> crystal directions were measured in three and four-point flexure. The biaxial strength was measured by subjecting <100> plates to a uniform pressure in a test apparatus that was developed and experimentally verified. The biaxial strengths of the single crystal plates were estimated by extending and verifying the displacement solution for a circular, anisotropic plate to the case of a variable radius and thickness. The best correlation between the experimental strength data and the model predictions occurred when an anisotropic stress analysis was combined with the normal stress criterion and the strength parameters associated with the <110> crystal direction.

  15. Calculation of Propulsive Nozzle Flowfields in Multidiffusing Chemically Reacting Environments. Ph.D. Thesis - Purdue Univ.

    NASA Technical Reports Server (NTRS)

    Kacynski, Kenneth John

    1994-01-01

    An advanced engineering model has been developed to aid in the analysis and design of hydrogen/oxygen chemical rocket engines. The complete multispecies, chemically reacting and multidiffusing Navier-Stokes equations are modelled, including the Soret thermal diffusion and the Dufour energy transfer terms. In addition to the spectrum of multispecies aspects developed, the model developed in this study is also conservative in axisymmetric flow for both inviscid and viscous flow environments and the boundary conditions employ a viscous, chemically reacting, reference plane characteristics method. Demonstration cases are presented for a 1030:1 area ratio nozzle, a 25 lbf film cooled nozzle, and a transpiration cooled plug and spool rocket engine. The results indicate that the thrust coefficient predictions of the 1030:1 and the 25 lbf film cooled nozzle are within 0.2 to 0.5 percent, respectively, of experimental measurements when all of the chemical reaction and diffusion terms are considered. Further, the model's predictions agree very well with the heat transfer measurements made in all of the nozzle test cases. The Soret thermal diffusion term is demonstrated to have a significant effect on the predicted mass fraction of hydrogen along the wall of the nozzle in both the laminar flow 1030:1 nozzle and the turbulent flow plug and spool nozzle analysis cases performed. Further, the Soret term was shown to represent an important fraction of the diffusion fluxes occurring in a transpiration cooled rocket engine.

  16. Boundary-layer separation on isolated boattail nozzles. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Abeyounis, W. K.

    1978-01-01

    An angle of attack of 0 deg was investigated in the Langley 16 foot transonic tunnel at free-stream Mach numbers from 0.40 to 0.95 to study the phenomenon of separated flow on a series of circular-arc afterbodies. Both high-pressure air and solid circular cylinders with the cylinder diameter equal to the nozzle-exit diameter were used to simulate jet exhausts. The results indicate that boundary-layer separation is most extensive on steep boattails at high Mach numbers. The jet total-pressure ratio changes (jet total pressure to free-stream static pressure) affected the extent of separation very little; however, comparison of the separation data obtained by using the two jet-simulation techniques indicate that entrainment associated with the presence of a jet had a significant effect on the extent of separation. The solid-simulator separation data were also used to evaluate the predictions of eight separation criteria.

  17. Dynamics of a class of vortex rings. Ph.D. Thesis - Stanford Univ.

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Leonard, Anthony; Ferziger, Joel H.

    1989-01-01

    The contour dynamics method is extended to vortex rings with vorticity varying linearly from the symmetry axis. An elliptic core model is also developed to explain some of the basic physics. Passage and collisions of two identical rings are studied focusing on core deformation, sound generation and stirring of fluid elements. With respect to core deformation, not only the strain rate but how rapidly it varies is important and accounts for greater susceptibility to vortex tearing than in two dimensions. For slow strain, as a passage interaction is completed and the strain relaxes, the cores return to their original shape while permanent deformations remain for rapidly varying strain. For collisions, if the strain changes slowly the core shapes migrate through a known family of two-dimensional steady vortex pairs up to the limiting member of the family. Thereafter energy conservation does not allow the cores to maintain a constant shape. For rapidly varying strain, core deformation is severe and a head-tail structure in good agreement with experiments is formed. With respect to sound generation, good agreement with the measured acoustic signal for colliding rings is obtained and a feature previously thought to be due to viscous effects is shown to be an effect of inviscid core deformation alone. For passage interactions, a component of high frequency is present. Evidence for the importance of this noise source in jet noise spectra is provided. Finally, processes of fluid engulfment and rejection for an unsteady vortex ring are studied using the stable and unstable manifolds. The unstable manifold shows excellent agreement with flow visualization experiments for leapfrogging rings suggesting that it may be a good tool for numerical flow visualization in other time periodic flows.

  18. Evolution of domain walls in the early universe. Ph.D. Thesis - Chicago Univ.

    NASA Technical Reports Server (NTRS)

    Kawano, Lawrence

    1989-01-01

    The evolution of domain walls in the early universe is studied via 2-D computer simulation. The walls are initially configured on a triangular lattice and then released from the lattice, their evolution driven by wall curvature and by the universal expansion. The walls attain an average velocity of about 0.3c and their surface area per volume (as measured in comoving coordinates) goes down with a slope of -1 with respect to conformal time, regardless of whether the universe is matter or radiation dominated. The additional influence of vacuum pressure causes the energy density to fall away from this slope and steepen, thus allowing a situation in which domain walls can constitute a significant portion of the energy density of the universe without provoking an unacceptably large perturbation upon the microwave background.

  19. Finite Element A Posteriori Error Estimation for Heat Conduction. Degree awarded by George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Lang, Christapher G.; Bey, Kim S. (Technical Monitor)

    2002-01-01

    This research investigates residual-based a posteriori error estimates for finite element approximations of heat conduction in single-layer and multi-layered materials. The finite element approximation, based upon hierarchical modelling combined with p-version finite elements, is described with specific application to a two-dimensional, steady state, heat-conduction problem. Element error indicators are determined by solving an element equation for the error with the element residual as a source, and a global error estimate in the energy norm is computed by collecting the element contributions. Numerical results of the performance of the error estimate are presented by comparisons to the actual error. Two methods are discussed and compared for approximating the element boundary flux. The equilibrated flux method provides more accurate results for estimating the error than the average flux method. The error estimation is applied to multi-layered materials with a modification to the equilibrated flux method to approximate the discontinuous flux along a boundary at the material interfaces. A directional error indicator is developed which distinguishes between the hierarchical modeling error and the finite element error. Numerical results are presented for single-layered materials which show that the directional indicators accurately determine which contribution to the total error dominates.

  20. [Theoretical studies in elementary particle physics]. [Physics Dept. , Pennsylvania State Univ

    SciTech Connect

    Collins, J.

    1992-01-01

    Work on the following topics is summarized: polarized hard scattering, hard diffraction, gauge-invariant operators, fundamental QCD, heavy quarks, strongly interacting Ws, and instanton-induced effects in QCD. Some attention is given to the factorization theorem.

  1. Resonance tube hazards in oxygen systems. Ph.D. Thesis - Toledo Univ., 1975

    NASA Technical Reports Server (NTRS)

    Phillips, B. R.

    1982-01-01

    An experimental and analytical program was carried out to determine whether fluid dynamic oscillations could create a hazard in gaseous oxygen flow systems. The particular fluid dynamic oscillation studied was the resonance tube phenomena as it was excited in a tee-shaped configuration characteristic of configurations found in many industrial high pressure gas flow systems. The types of hazards that could be caused by the oscillations were direct heating and ignition of the piping system by the gas, the greatly augmented heating that could occur if inert contaminants were present, and the ignition of metallic contaminants. Asbestos was used as the inert contaminant; titanium, aluminum, magnesium and steel were chosen as ignitable metallic contaminants. The oscillations in the tee-shaped configuration were compared to oscillations driven by choked convergent nozzles and were found to differ markedly. Temperature generated at the end or base of the resonance tube exceeded 1089 K for both gaseous oxygen and nitrogen and reached 1645 K when asbestos was added. Aluminum in both powder and fiber form was readily ignited within the resonance tube when the supply pressures were less than 8270 kPa whereas at higher supply pressures the mixture exploded with enough violence to destory the apparatus in less than 10 sec. In addition to aluminum, magnesium, and titanium, samples of 400 series stainless steels were also ignited within the resonance tube. The ignition occurred within a few seconds after the oxygen flow began.

  2. Theory of electron induced reactions. Progress report, May 1, 1980-April 30, 1981. [Ohio Univ

    SciTech Connect

    Onley, D.S.; Wright, L.E.

    1981-02-01

    (I) The problem of finite-size effects in virtual photon spectra was studied from several directions. It was found that a model-independent correction to the spectrum could be defined for energies up to 200 MeV. It is shown, however, that drastically different current distributions for an M1 transition all share the same transition radius and produce the same correction to the M1 virtual spectrum. This insensitivity to details of the transition is evidently due to a predominance of low-momentum-transfer components, which selects only comparatively low moments of the corresponding form factors. Simultaneous correction for finite size and Coulomb forces (finite charge) was studied, and an alarming interaction between the two corrections was found. (II) Coulomb distortion effects in pair production were also calculated. The distortion factor, which is the ratio of the total pair production cross section with Coulomb distortion to the plane-wave (Bethe-Heitler) result, is shown as a function of photon energy for Z = 92. (III) Some work was also done on pion electroproduction. The model showed good agreement with available experimental data. 8 figures. (RWR)

  3. Pulmonary Edema and Plasma Volume Changes in Dysbarism. M.S. Thesis - Texas Univ.

    NASA Technical Reports Server (NTRS)

    Joki, J. A.

    1972-01-01

    Two groups of anesthetized, fasted pigs were utilized. One group of 13 animals (8.5 to 16.6 kilograms) was exposed to a high-pressure environment, and the other group of eight animals (6.9 to 20.0 kilograms) constituted the control group. The experimental group was subjected to an atmosphere of 90 percent nitrogen and 10 percent oxygen at a pressure of 50 psig for 30 minutes and then decompressed at a rate 10 psi/min. Plasma volumes, using both iodine-125-tagged-albumin and chromium-51-tagged-cell dilution techniques, were measured before, immediately after, and at 30 and 60 minutes after decompression. Aortic and right-ventricular systolic pressures were also recorded. At 60 minutes after decompression, blood samples were taken, the animals were sacrificed, and the water content of the lungs, kidneys, livers, and spleens was estimated by measuring tissue wet weight and dry weight. Protein extravasation and tissue blood volumes were determined by measuring the iodine-125-tagged-albumin and chromium-51-tagged-cell spaces in homo-genates of the organs under investigation.

  4. On the Nature of Navier-stokes Turbulence. Ph.D. Thesis - Case Western Reserve Univ.

    NASA Technical Reports Server (NTRS)

    Deissler, Robert G.

    1989-01-01

    Several turbulent and nonturbulent solutions of the Navier-Stokes equations are obtained. The unaveraged equations are used numerically in conjunction with tools and concepts from nonlinear dynamics, including time series, phase portraits, Poincare sections, largest Liapunov exponents, power spectra, and strange attractors. Initially neighboring solutions for a low-Reynolds-number fully developed turbulence are compared. The solutions, separate exponentially with time, having a positive Liapunov exponent. Thus the turbulence is characterized as chaotic. In a search for solutions which contrast with the turbulent ones, the Reynolds number is reduced. Several qualitatively different flows are noted. These are, fully chaotic, complex period, weakly chaotic, simple periodic, and fixed-point. Of these, only the fully chaotic flows are classified as turbulent. Those flows have both a positive Liapunov exponent and Poincare sections without pattern. By contrast, the weakly chaotic flows have some pattern in their Poincare sections. The fixed-point and periodic flows are nonturbulent, since turbulence, is both time-dependent and aperiodic. Turbulent solutions are obtained in which energy cascades from large to small-scale motions. In general, the spectral energy transfer takes place between wavenumber bands that are considerably separated. The special transfer can occur either as a result of nonlinear turbulence self-interaction or by interaction of turbulence with mean gradients. Turbulent systems are compared with those studied in kinetic theory. The two types of systems are fundamentally different (continuous and dissipative as opposed to discrete and conservative), but there are similarities. For instance, both are nonlinear and show sensitive dependence on initial conditions. Also, the turbulent and molecular stress tensors are identical if the macroscopic velocities for the turbulent stress are replaced by molecular velocities.

  5. Elementary particle interactions. [Dept. of Physics and Astronomy, Univ. of Tennessee, Knoxville, Tennessee

    SciTech Connect

    Bugg, W.M.; Condo, G.T.; Handler, T.; Hart, E.L.; Read, K.; Ward, B.F.L.

    1992-10-01

    Work continues on strange particle production in weak interactions using data from a high-energy neutrino exposure in a freon bubble chamber. Meson photoproduction has also consumed considerable effort. Detector research and development activities have been carried out.

  6. Experimental study of void formation during aluminum solidification in reduced gravity. Ph. D. Thesis - Toledo Univ

    SciTech Connect

    Chiaramonte, F.P. III.

    1993-10-01

    Void formation due to volumetric shrinkage and liquid/vapor reorientation during aluminum solidification was observed in real time by using a radiographic viewing system in normal and reduced gravity. An end-chill directional solidification furnace with water quench was designed and constructed to solidify aluminum samples during the approximately 16 sec of reduced gravity (+/-0.02g) achieved by flying an aircraft through a parabolic trajectory. In the first series of tests the aluminum was contained in a vacuum sealed, pyrolytic boron nitride crucible. An ullage space was present during each test. Void formation was recorded for two cases: a nonwetting system, and a wetting system where wetting occurred between the aluminum and the crucible lid. The void formation in the nonwetting case was similar in normal and reduced gravity, with a single vapor cavity forming at the top of the crucible. In the wetting case during reduced gravity surface tension caused two voids to form in the top corners of the crucible, but during normal gravity only one large void formed across the top. In the second series of tests the aluminum was contained in a pyrolytic boron nitride crucible that was placed in a stainless steel container and sealed in an environment of argon plus 4 percent hydrogen. An ullage space was present during each test. Void formation was recorded for two cases: a nonwetting system, and a wetting system where wetting occurred between the aluminum and one side wall and the lid. The void formation in the nonwetting case was similar in normal and reduced gravity, with a single vapor cavity forming at the top of the crucible, although the meniscus became more convex in reduced gravity. In the wetting case the aluminum did not climb up the corners in 1g, and one large symmetric void resulted at the top when the aluminum had solidified.

  7. Random Process Simulation for stochastic fatigue analysis. Ph.D. Thesis - Rice Univ., Houston, Tex.

    NASA Technical Reports Server (NTRS)

    Larsen, Curtis E.

    1988-01-01

    A simulation technique is described which directly synthesizes the extrema of a random process and is more efficient than the Gaussian simulation method. Such a technique is particularly useful in stochastic fatigue analysis because the required stress range moment E(R sup m), is a function only of the extrema of the random stress process. The family of autoregressive moving average (ARMA) models is reviewed and an autoregressive model is presented for modeling the extrema of any random process which has a unimodal power spectral density (psd). The proposed autoregressive technique is found to produce rainflow stress range moments which compare favorably with those computed by the Gaussian technique and to average 11.7 times faster than the Gaussian technique. The autoregressive technique is also adapted for processes having bimodal psd's. The adaptation involves using two autoregressive processes to simulate the extrema due to each mode and the superposition of these two extrema sequences. The proposed autoregressive superposition technique is 9 to 13 times faster than the Gaussian technique and produces comparable values for E(R sup m) for bimodal psd's having the frequency of one mode at least 2.5 times that of the other mode.

  8. Simulator investigation of wind shear recovery techniques. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Hinton, David A.

    1988-01-01

    The objective was the development of practical flight procedures and guidance for near-optimal trajectories during inadvertent wind shear encounters following takeoff. The approach was to conduct preliminary development of candidate strategies using batch simulation of the point mass B737-100 performance model and to evaluate candidate guidance strategies in piloted, real time, six degrees of freedom simulation.

  9. Study of effects of small perturbations on chaotic systems. [Univ. of Maryland, College Park, Maryland

    SciTech Connect

    Grebogi, C.; Yorke, J.A.

    1993-01-01

    Very brief summaries are given of work on the following topics: prevalence, border crossing bifurcations, numerical procedure for computing the dimension, generalized saddle straddle trajectories methods, and finding typical trajectories numerically.

  10. Collider Physics: SDC/SSC liquified fiber calorimetry. [Physics Dept. , Texas A M Univ

    SciTech Connect

    White, J.T.; Huson, F.R.

    1992-01-01

    Most effort was directed toward the D-Zero experiment at Fermilab. Over 3 pb[sup [minus]1] of high-quality physics data have been obtained. Analysis of the results (wino-zino physics, squark physics), D-zero data acquisition systems efforts, and level-1 and level-2 trigger work are described. Other work concerned detector development for use at the SSC. This technology consists of using liquid scintillator-filled tubes as scintillating fibers for a calorimeter.'' The key issues were to demonstrate that the liquid fibers were sufficiently rad-hard and to demonstrate that fibers with sufficiently long attenuation length could be found to satisfy the resolution requirements; both constraints could be satisfied.

  11. Quantization noise in digital speech. M.S. Thesis- Houston Univ.

    NASA Technical Reports Server (NTRS)

    Schmidt, O. L.

    1972-01-01

    The amount of quantization noise generated in a digital-to-analog converter is dependent on the number of bits or quantization levels used to digitize the analog signal in the analog-to-digital converter. The minimum number of quantization levels and the minimum sample rate were derived for a digital voice channel. A sample rate of 6000 samples per second and lowpass filters with a 3 db cutoff of 2400 Hz are required for 100 percent sentence intelligibility. Consonant sounds are the first speech components to be degraded by quantization noise. A compression amplifier can be used to increase the weighting of the consonant sound amplitudes in the analog-to-digital converter. An expansion network must be installed at the output of the digital-to-analog converter to restore the original weighting of the consonant sounds. This technique results in 100 percent sentence intelligibility for a sample rate of 5000 samples per second, eight quantization levels, and lowpass filters with a 3 db cutoff of 2000 Hz.

  12. Studies in theoretical high energy particle physics. [Dept. of Physics, Univ. of Illinois at Chicago

    SciTech Connect

    Aratyn, H.; Brekke, L.; Keung, Wai-Yee; Sukhatme, U.

    1993-01-01

    Theoretical work on the following topics is briefly summarized: symmetry structure of conformal affine Toda model and KP hierarchy; solitons in the affine Toda and conformal affine Toda models; classical r-matrices and Poisson bracket structures on infinite-dimensional groups; R-matrix formulation of KP hierarchies and their gauge equivalence; statistics of particles and solitons; charge quantization in the presence of an Alice string; knotting and linking of nonabelian flux; electric dipole moments; neutrino physics in gauge theories; CP violation in the high energy colliders; supersymmetric quantum mechanics; parton structure functions in nuclei; dual parton model. 38 refs.

  13. [Research programs on elementary particle and field theories and superconductivity]. [Rockefeller Univ

    SciTech Connect

    Khuri, N.N.

    1992-01-01

    Research of staff members in theoretical physics is presented in the following areas: super string theory, a new approach to path integrals, new ideas on the renormalization group, nonperturbative chiral gauge theories, the standard model, K meson decays, and the CP problem. Work on high-[Tc] superconductivity and protein folding is also related.

  14. Advanced propulsion for LEO-Moon transport. 3: Transportation model. M.S. Thesis - California Univ.

    NASA Technical Reports Server (NTRS)

    Henley, Mark W.

    1992-01-01

    A simplified computational model of low Earth orbit-Moon transportation system has been developed to provide insight into the benefits of new transportation technologies. A reference transportation infrastructure, based upon near-term technology developments, is used as a departure point for assessing other, more advanced alternatives. Comparison of the benefits of technology application, measured in terms of a mass payback ratio, suggests that several of the advanced technology alternatives could substantially improve the efficiency of low Earth orbit-Moon transportation.

  15. The sound of moving bodies. Ph.D. Thesis - Cambridge Univ.

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth Steven

    1990-01-01

    The importance of the quadrupole source term in the Ffowcs, Williams, and Hawkings (FWH) equation was addressed. The quadrupole source contains fundamental components of the complete fluid mechanics problem, which are ignored only at the risk of error. The results made it clear that any application of the acoustic analogy should begin with all of the source terms in the FWH theory. The direct calculation of the acoustic field as part of the complete unsteady fluid mechanics problem using CFD is considered. It was shown that aeroelastic calculation can indeed be made with CFD codes. The results indicate that the acoustic field is the most susceptible component of the computation to numerical error. Therefore, the ability to measure the damping of acoustic waves is absolutely essential both to develop acoustic computations. Essential groundwork for a new approach to the problem of sound generation by moving bodies is presented. This new computational acoustic approach holds the promise of solving many problems hitherto pushed aside.

  16. Laboratory EXAFS facilities-1980. [Univ. of Washington, Seattle, April 28-30, 1980

    SciTech Connect

    Stern, E.A.

    1980-01-01

    Individual abstracts were prepared for the papers given at this conference. One of these papers has already been cited in ERA, and may be located by reference to the entry CONF-800487--1 in the Report Number Index. The remaining papers will be added to the data base when they are received on tape from AIP. (RWR)

  17. An investigation of gear mesh failure prediction techniques. M.S. Thesis - Cleveland State Univ.

    NASA Technical Reports Server (NTRS)

    Zakrajsek, James J.

    1989-01-01

    A study was performed in which several gear failure prediction methods were investigated and applied to experimental data from a gear fatigue test apparatus. The primary objective was to provide a baseline understanding of the prediction methods and to evaluate their diagnostic capabilities. The methods investigated use the signal average in both the time and frequency domain to detect gear failure. Data from eleven gear fatigue tests were recorded at periodic time intervals as the gears were run from initiation to failure. Four major failure modes, consisting of heavy wear, tooth breakage, single pits, and distributed pitting were observed among the failed gears. Results show that the prediction methods were able to detect only those gear failures which involved heavy wear or distributed pitting. None of the methods could predict fatigue cracks, which resulted in tooth breakage, or single pits. It is suspected that the fatigue cracks were not detected because of limitations in data acquisition rather than in methodology. Additionally, the frequency response between the gear shaft and the transducer was found to significantly affect the vibration signal. The specific frequencies affected were filtered out of the signal average prior to application of the methods.

  18. Estimation from incomplete multinomial data. Ph.D. Thesis - Harvard Univ.

    NASA Technical Reports Server (NTRS)

    Credeur, K. R.

    1978-01-01

    The vector of multinomial cell probabilities was estimated from incomplete data, incomplete in that it contains partially classified observations. Each such partially classified observation was observed to fall in one of two or more selected categories but was not classified further into a single category. The data were assumed to be incomplete at random. The estimation criterion was minimization of risk for quadratic loss. The estimators were the classical maximum likelihood estimate, the Bayesian posterior mode, and the posterior mean. An approximation was developed for the posterior mean. The Dirichlet, the conjugate prior for the multinomial distribution, was assumed for the prior distribution.

  19. [High energy physics research]: Annual performance report, December 1, 1991--November 30, 1992. [Northwestern Univ

    SciTech Connect

    Rosen, J; Block, M; Buchholz, D; Gobbi, B; Schellman, H; Buchholz, D; Rosen, J; Miller, D; Braaten, E; Chang, D; Oakes, R; Schellman, H

    1992-01-01

    The various segments of the Northwestern University high energy physics research program are reviewed. Work is centered around experimental studies done primarily at FNAL; associated theoretical efforts are included.

  20. Residual Stress Reversal in Highly Strained Shot Peened Structural Elements. Degree awarded by Florida Univ.

    NASA Technical Reports Server (NTRS)

    Mitchell, William S.; Throckmorton, David (Technical Monitor)

    2002-01-01

    The purpose of this research was to further the understanding of a crack initiation problem in a highly strained pressure containment housing. Finite Element Analysis methods were used to model the behavior of shot peened materials undergoing plastic deformation. Analytical results are in agreement with laboratory tensile tests that simulated the actual housing load conditions. These results further validate the original investigation finding that the shot peened residual stress had reversed, changing from compressive to tensile, and demonstrate that analytical finite element methods can be used to predict this behavior.

  1. Elementary particle physics and high energy phenomena. [Dept. of Physics, Univ. of Colorado, Boulder, Colorado

    SciTech Connect

    Barker, A.R.; Cumalat, J.P.; De Alwis, S.P.; DeGrand, T.A.; Ford, W.T.; Mahanthappa, K.T.; Nauenberg, U.; Rankin, P.; Smith, J.G.

    1992-06-01

    Experimental and theoretical high-energy physics programs at the University of Colorado are reported. Areas of concentration include the following: study of the properties of the Z[sup 0] with the SLD detector; fixed-target K-decay experiments; the R D program for the muon system: the SDC detector; high-energy photoproduction of states containing heavy quarks; electron--positron physics with the CLEO II detector at CESR; lattice QCD; and spin models and dynamically triangulated random surfaces. 24 figs., 2 tabs., 117 refs.

  2. Numerical simulation of separated flows. Ph.D. Thesis - Stanford Univ., Calif.

    NASA Technical Reports Server (NTRS)

    Spalart, P. R.; Leonard, A.; Baganoff, D.

    1983-01-01

    A new numerical method, based on the Vortex Method, for the simulation of two-dimensional separated flows, was developed and tested on a wide range of gases. The fluid is incompressible and the Reynolds number is high. A rigorous analytical basis for the representation of the Navier-Stokes equation in terms of the vorticity is used. An equation for the control of circulation around each body is included. An inviscid outer flow (computed by the Vortex Method) was coupled with a viscous boundary layer flow (computed by an Eulerian method). This version of the Vortex Method treats bodies of arbitrary shape, and accurately computes the pressure and shear stress at the solid boundary. These two quantities reflect the structure of the boundary layer. Several versions of the method are presented and applied to various problems, most of which have massive separation. Comparison of its results with other results, generally experimental, demonstrates the reliability and the general accuracy of the new method, with little dependence on empirical parameters. Many of the complex features of the flow past a circular cylinder, over a wide range of Reynolds numbers, are correctly reproduced.

  3. National Seminar on Vocational Guidance. (Northern Michigan Univ., Marquette, August 21-26, 1966). Final Report.

    ERIC Educational Resources Information Center

    American Personnel and Guidance Association, Washington, DC.

    The achievement of more adequate vocational guidance services in the nation's schools through the improvement of state supervisory service, was the major objective of the seminar. In additon to 72 state guidance supervisory staff members from 47 states, seminar participants and leadership personnel included 14 counselor educators, 12 state-level…

  4. Contribution to the study of composite materials and their damage. Thesis - Paris VI Univ. - 1984

    NASA Technical Reports Server (NTRS)

    Lene, F.

    1987-01-01

    Chapter 1 describes the homogenization techniques used for defining the overall behavior of composite materials for conventional cases of linear and perfectly glued elastic constituents. Chapters 2 and 3 focus on solving the problems inherent in two types of degenerated situations: elastic media with microcavities, and elastic media containing rigid inclusions. Through suitable definitions of deformation concepts and macroscopic stresses it is shown that conventional theory results apply naturally to these limits.

  5. Pulsed multiwavelength laser ranging system. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Abshire, J. B.

    1982-01-01

    A pulsed multiwavelength laser ranging system for measuring atmospheric delay was built and tested, and its theoretical performance limits were calculated. The system uses a dye modelocked ND:YAG laser, which transmits 70 psec wide pulses simultaneously at 1064, 532, and 355 nm. The differential delay of the 1064 and 355 nm pulses is measured by a specially calibrated waveform digitizer to estimate the dry atmospheric delay. The delay time of the 532 nm pulse is used to measure the target distance. Static crossed field photomultipliers are used as detectors for all wavelengths. Theoretical analysis shows that path curvature and atmospheric turbulence are fundamental limits to the ranging accuracy of both single and multicolor systems operating over horizontal paths. For two color systems, an additional error is caused by the uncertainty in the path averaged water vapor. The standard deviation of the multicolor instrument's timing measurements is directly proportional to the laser pulse width plus photomultiplier jitter divided by the square root of the received photoelectron number. The prototype system's maximum range is km, which is limited by atmospheric and system transmission losses at 355 nm. System signal detection and false alarm calculations are also presented.

  6. A contracting-interval program for the Danilewski method. Ph.D. Thesis - Va. Univ.

    NASA Technical Reports Server (NTRS)

    Harris, J. D.

    1971-01-01

    The concept of contracting-interval programs is applied to finding the eigenvalues of a matrix. The development is a three-step process in which (1) a program is developed for the reduction of a matrix to Hessenberg form, (2) a program is developed for the reduction of a Hessenberg matrix to colleague form, and (3) the characteristic polynomial with interval coefficients is readily obtained from the interval of colleague matrices. This interval polynomial is then factored into quadratic factors so that the eigenvalues may be obtained. To develop a contracting-interval program for factoring this polynomial with interval coefficients it is necessary to have an iteration method which converges even in the presence of controlled rounding errors. A theorem is stated giving sufficient conditions for the convergence of Newton's method when both the function and its Jacobian cannot be evaluated exactly but errors can be made proportional to the square of the norm of the difference between the previous two iterates. This theorem is applied to prove the convergence of the generalization of the Newton-Bairstow method that is used to obtain quadratic factors of the characteristic polynomial.

  7. Hydrodynamic models of a cepheid atmosphere. Ph.D. Thesis - Maryland Univ., College Park

    NASA Technical Reports Server (NTRS)

    Karp, A. H.

    1974-01-01

    A method for including the solution of the transfer equation in a standard Henyey type hydrodynamic code was developed. This modified Henyey method was used in an implicit hydrodynamic code to compute deep envelope models of a classical Cepheid with a period of 12(d) including radiative transfer effects in the optically thin zones. It was found that the velocity gradients in the atmosphere are not responsible for the large microturbulent velocities observed in Cepheids but may be responsible for the occurrence of supersonic microturbulence. It was found that the splitting of the cores of the strong lines is due to shock induced temperature inversions in the line forming region. The adopted light, color, and velocity curves were used to study three methods frequently used to determine the mean radii of Cepheids. It is concluded that an accuracy of 10% is possible only if high quality observations are used.

  8. Dynamics of a split torque helicopter transmission. M.S. Thesis - Cleveland State Univ.

    NASA Technical Reports Server (NTRS)

    Krantz, Timothy L.

    1994-01-01

    Split torque designs, proposed as alternatives to traditional planetary designs for helicopter main rotor transmissions, can save weight and be more reliable than traditional designs. This report presents the results of an analytical study of the system dynamics and performance of a split torque gearbox that uses a balance beam mechanism for load sharing. The Lagrange method was applied to develop a system of equations of motion. The mathematical model includes time-varying gear mesh stiffness, friction, and manufacturing errors. Cornell's method for calculating the stiffness of spur gear teeth was extended and applied to helical gears. The phenomenon of sidebands spaced at shaft frequencies about gear mesh fundamental frequencies was simulated by modeling total composite gear errors as sinusoid functions. Although the gearbox has symmetric geometry, the loads and motions of the two power paths differ. Friction must be considered to properly evaluate the balance beam mechanism. For the design studied, the balance beam is not an effective device for load sharing unless the coefficient of friction is less than 0.003. The complete system stiffness as represented by the stiffness matrix used in this analysis must be considered to precisely determine the optimal tooth indexing position.

  9. Thermal behavior spiral bevel gears. Ph.D. Thesis - Case Western Univ., Aug. 1993

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.

    1995-01-01

    An experimental and analytical study of the thermal behavior of spiral bevel gears is presented. Experimental data were taken using thermocoupled test hardware and an infrared microscope. Many operational parameters were varied to investigate their effects on the thermal behavior. The data taken were also used to validate the boundary conditions applied to the analytical model. A finite element-based solution sequence was developed. The three-dimensional model was developed based on the manufacturing process for these gears. Contact between the meshing gears was found using tooth contact analysis to describe the location, curvatures, orientations, and surface velocities. This information was then used in a three-dimensional Hertzian contact analysis to predict contact ellipse size and maximum pressure. From these results, an estimate of the heat flux magnitude and the location on the finite element model was made. The finite element model used time-averaged boundary conditions to permit the solution to attain steady state in a computationally efficient manner.Then time- and position-varying boundary conditions were applied to the model to analyze the cyclic heating and cooling due to the gears meshing and transferring heat to the surroundings, respectively. The model was run in this mode until the temperature behavior stabilized. The transient flash temperature on the surface was therefore described. The analysis can be used to predict the overall expected thermal behavior of spiral bevel gears. The experimental and analytical results were compared for this study and also with a limited number of other studies. The experimental and analytical results attained in the current study were basically within 10% of each other for the cases compared. The experimental comparison was for bulk thermocouple locations and data taken with an infrared microscope. The results of a limited number of other studies were compared with those obtained herein and predicted the same basic behavior.

  10. The project scientist's role in scientific spacecraft project management. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Eller, E. L.

    1976-01-01

    The project scientists is in a position which rates very high in terms of behavioral study recommendations. His influence over objectives is generally considered to be important. He is highly autonomous in a moderately coordinated environment. He has diverse managerial and technical functions and the performance of these functions require him to grow beyond his role as an experimenter. However, the position within the line organization for those interviewed is also very stimulating, rating almost as high by the same criteria. The role of project scientist may not be the dominant means of professional growth for the experienced scientific investigators. The influence which the project scientist exerts on the project and the stimulation of that position for him are determined largely by his position outside the defined project scientist role. The role of the project scientist is changing because the environment of those who become project scientists is changing.

  11. Contribution to the Performance Determination of Microjets. Ph.D. Thesis - Technical Univ., Feb. 1983

    NASA Technical Reports Server (NTRS)

    Hayn, D.

    1984-01-01

    Theoretical investigations are made on the performance of microjets. A description is given of experiments with micropropulsion units to correlate the results obtained in the first part of the report. Execution of performance measurements is discussed, and error calculations are presented.

  12. Liquid crystal point diffraction interferometer. Ph.D. Thesis - Arizona Univ., 1995

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.

    1995-01-01

    A new instrument, the liquid crystal point diffraction-interferometer (LCPDI), has been developed for the measurement of phase objects. This instrument maintains the compact, robust design of Linnik's point diffraction interferometer (PDI) and adds to it phase stepping capability for quantitative interferogram analysis. The result is a compact, simple to align, environmentally insensitive interferometer capable of accurately measuring optical wavefronts with very high data density and with automated data reduction. This dissertation describes the theory of both the PDI and liquid crystal phase control. The design considerations for the LCPDI are presented, including manufacturing considerations. The operation and performance of the LCPDI are discussed, including sections regarding alignment, calibration, and amplitude modulation effects. The LCPDI is then demonstrated using two phase objects: defocus difference wavefront, and a temperature distribution across a heated chamber filled with silicone oil. The measured results are compared to theoretical or independently measured results and show excellent agreement. A computer simulation of the LCPDI was performed to verify the source of observed periodic phase measurement error. The error stems from intensity variations caused by dye molecules rotating within the liquid crystal layer. Methods are discussed for reducing this error. Algorithms are presented which reduce this error; they are also useful for any phase-stepping interferometer that has unwanted intensity fluctuations, such as those caused by unregulated lasers.

  13. Chaotic dynamics in accelerator physics. [Dept. of Astrophysical, Planetary, and Atmospheric Sciences, Univ. of Colorado, Boulder

    SciTech Connect

    Cary, J.R.

    1992-11-30

    Substantial progress was in several areas of accelerator dynamics. For developing understanding of longitudinal adiabatic dynamics, and for creating efficiency enhancements of recirculating free-electron lasers, was substantially completed. A computer code for analyzing the critical KAM tori that bound the dynamic aperture in circular machines was developed. Studies of modes that arise due to the interaction of coating beams with a narrow-spectrum impedance have begun. During this research educational and research ties with the accelerator community at large have been strengthened.

  14. On the Physical Environment in the Galactic Nuclei. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Beall, J. H.

    1979-01-01

    Galactic nuclei and quasars emit radiation over the entire electromagnetic spectrum. This suggests that concurrent observations over a wide frequency range may provide useful information in determining appropriate models for the physical environment in which the radiation is produced. In conjunction with observations by the high energy spectrometer on OSO-8, four sources have been studied in this manner; the nucleus of the elliptical galaxy, Centaurus A (NGG 5128); the quasar, 30273; the Seyfert galaxy, NGC 4151 and the nucleus of the Milky Way (GCX). Concurrent observations are used to construct the composite spectra (from radio to X-ray) for Cen A and NGC 4151 while the composite spectra of 30273 and GCX are derived from the OSO-8 data and from other observers. A skymap technique used to analyze observations of the galactic center region yielded data consistent with a significant, hard X-ray source at the radio and infrared position of the nucleus of the Milky Way. A theoretical analysis of the temporal variability of the Cen A data is undertaken and its implications discussed. Similarities between the composite spectra of the observed sources suggest that radio-bright and radio-quiet quasars may represent the emission from galactic nuclei with elliptical and Seyfert-like morphologies, respectively.

  15. The Numerical Analysis of a Turbulent Compressible Jet. Degree awarded by Ohio State Univ., 2000

    NASA Technical Reports Server (NTRS)

    DeBonis, James R.

    2001-01-01

    A numerical method to simulate high Reynolds number jet flows was formulated and applied to gain a better understanding of the flow physics. Large-eddy simulation was chosen as the most promising approach to model the turbulent structures due to its compromise between accuracy and computational expense. The filtered Navier-Stokes equations were developed including a total energy form of the energy equation. Subgrid scale models for the momentum and energy equations were adapted from compressible forms of Smagorinsky's original model. The effect of using disparate temporal and spatial accuracy in a numerical scheme was discovered through one-dimensional model problems and a new uniformly fourth-order accurate numerical method was developed. Results from two- and three-dimensional validation exercises show that the code accurately reproduces both viscous and inviscid flows. Numerous axisymmetric jet simulations were performed to investigate the effect of grid resolution, numerical scheme, exit boundary conditions and subgrid scale modeling on the solution and the results were used to guide the three-dimensional calculations. Three-dimensional calculations of a Mach 1.4 jet showed that this LES simulation accurately captures the physics of the turbulent flow. The agreement with experimental data was relatively good and is much better than results in the current literature. Turbulent intensities indicate that the turbulent structures at this level of modeling are not isotropic and this information could lend itself to the development of improved subgrid scale models for LES and turbulence models for RANS simulations. A two point correlation technique was used to quantify the turbulent structures. Two point space correlations were used to obtain a measure of the integral length scale, which proved to be approximately 1/2 D(sub j). Two point space-time correlations were used to obtain the convection velocity for the turbulent structures. This velocity ranged from 0.57 to 0.71 U(sub j).

  16. [Investigations in dynamics of gauge theories in theoretical particle physics]. [Virginia Polytechnic Institute State Univ. , Blacksburg

    SciTech Connect

    Not Available

    1993-01-01

    The major theme of the theoretical physics research conducted under DOE support over the past several years has been within the rubric of the standard model, and concerned the interplay between symmetries and dynamics. The research was thus carried out mostly in the context of gauge field theories, and usually in the presence of chiral fermions. Dynamical symmetry breaking was examined both from the point of view of perturbation theory, as well as from non-perturbative techniques associated with certain characteristic features of specific theories. Among the topics of research were: the implications of abelian and non-abelian anomalies on the spectrum and possible dynamical symmetry breaking in any theory, topological and conformal properties of quantum fields in two and higher dimensions, the breaking of global chiral symmetries by vector-like gauge theories such as QCD, the phenomenological implications of a strongly interacting Higgs sector in the standard model, and the application of soliton ideas to the physics to be explored at the SSC.

  17. Liquid jet impingement normal to a disk in zero gravity. Ph.D. Thesis Toledo Univ.

    NASA Technical Reports Server (NTRS)

    Labus, T. L.

    1977-01-01

    The free surface shapes of circular liquid jets impinging normal to sharp-edged disks in zero gravity are determined. Zero gravity drop tower experiments yielded three distinct flow patterns that were classified in terms of the relative effects of surface tension and inertial forces. An order of magnitude analysis was conducted that indicated regions where viscous forces were not significant in the computation of free surface shapes. The free surface analysis was simplified by transforming the governing potential flow equations and boundary conditions into the inverse plane, where the stream function and velocity potential became the coordinates. The resulting nonlinear equations were solved by standard finite difference methods, and comparisons were made with the experimental data for the inertia dominated regime.

  18. (Calorimeter based detectors for high energy hadron colliders). [State Univ. of New York

    SciTech Connect

    Not Available

    1992-08-04

    This document provides a progress report on research that has been conducted under DOE Grant DEFG0292ER40697 for the past year, and describes proposed work for the second year of this 8 year grant starting November 15, 1992. Personnel supported by the contract include 4 faculty, 1 research faculty, 4 postdocs, and 9 graduate students. The work under this grant has in the past been directed in two complementary directions -- DO at Fermilab, and the second SSC detector GEM. A major effort has been towards the construction and commissioning of the new Fermilab Collider detector DO, including design, construction, testing, the commissioning of the central tracking and the central calorimeters. The first DO run is now underway, with data taking and analysis of the first events. Trigger algorithms, data acquisition, calibration of tracking and calorimetry, data scanning and analysis, and planning for future upgrades of the DO detector with the advent of the FNAL Main Injector are all involved. The other effort supported by this grant has been towards the design of GEM, a large and general-purpose SSC detector with special emphasis on accurate muon measurement over a large solid angle. This effort will culminate this year in the presentation to the SSC laboratory of the GEM Technical Design Report. Contributions are being made to the detector design, coordination, and physics simulation studies with special emphasis on muon final states. Collaboration with the RD5 group at CERN to study muon punch through and to test cathode strip chamber prototypes was begun.

  19. Photogrammetry and Videogrammetry Methods Development for Solar Sail Structures. Masters Thesis awarded by George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Pappa, Richard S. (Technical Monitor); Black, Jonathan T.

    2003-01-01

    This report discusses the development and application of metrology methods called photogrammetry and videogrammetry that make accurate measurements from photographs. These methods have been adapted for the static and dynamic characterization of gossamer structures, as four specific solar sail applications demonstrate. The applications prove that high-resolution, full-field, non-contact static measurements of solar sails using dot projection photogrammetry are possible as well as full-field, non-contact, dynamic characterization using dot projection videogrammetry. The accuracy of the measurement of the resonant frequencies and operating deflection shapes that were extracted surpassed expectations. While other non-contact measurement methods exist, they are not full-field and require significantly more time to take data.

  20. Analysis of pressure spectra measurements in a ducted combustion system. Ph.D. Thesis - Toledo Univ.

    NASA Technical Reports Server (NTRS)

    Miles, J. H.

    1980-01-01

    Combustion noise propagation in an operating ducted liquid fuel combustion system is studied in relation to the development of combustion noise prediction and suppression techniques. The presence of combustor emissions in the duct is proposed as the primary mechanism producing the attenuation and dispersion of combustion noise propagating in an operating liquid fuel combustion system. First, a complex mathematical model for calculating attenuation and dispersion taking into account mass transfer, heat transfer, and viscosity effects due to the presence of liquid fuel droplets or solid soot particles is discussed. Next, a simpler single parameter model for calculating pressure auto-spectra and cross-spectra which takes into account dispersion and attenuation due to heat transfer between solid soot particles and air is developed. Then, auto-spectra and cross-spectra obtained from internal pressure measurements in a combustion system consisting of a J-47 combustor can, a spool piece, and a long duct are presented. Last, analytical results obtained with the single parameter model are compared with the experimental measurements. The single parameter model results are shown to be in excellent agreement with the measurements.

  1. Theoretical interpretation of high-energy nuclear collisions. [Kent State Univ

    SciTech Connect

    Fai, G.

    1992-06-01

    Nuclear collisions are interpreted theoretically. The nuclear equation of state is studied in a wide energy range. Subnucleonic degrees of freedom are invoked at high energy densities and at short length-scales. Questions of dynamical collision simulations are investigated. Direct support is provided for experiment in the form of collaborative projects. The major objective of this nuclear theory program is a better understanding of the properties of strongly interacting matter on the nuclear energy scale, as manifested in high-energy heavy-ion collisions.

  2. An Analysis of NASA Technology Transfer. Degree awarded by Pennsylvania State Univ.

    NASA Technical Reports Server (NTRS)

    Bush, Lance B.

    1996-01-01

    A review of previous technology transfer metrics, recommendations, and measurements is presented within the paper. A quantitative and qualitative analysis of NASA's technology transfer efforts is performed. As a relative indicator, NASA's intellectual property performance is benchmarked against a database of over 100 universities. Successful technology transfer (commercial sales, production savings, etc.) cases were tracked backwards through their history to identify the key critical elements that lead to success. Results of this research indicate that although NASA's performance is not measured well by quantitative values (intellectual property stream data), it has a net positive impact on the private sector economy. Policy recommendations are made regarding technology transfer within the context of the documented technology transfer policies since the framing of the Constitution. In the second thrust of this study, researchers at NASA Langley Research Center were surveyed to determine their awareness of, attitude toward, and perception about technology transfer. Results indicate that although researchers believe technology transfer to be a mission of the Agency, they should not be held accountable or responsible for its performance. In addition, the researchers are not well educated about the mechanisms to perform, or policies regarding, technology transfer.

  3. Noise transmission through plates into an enclosure. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Mcdonald, W. B.; Vaicaitis, R.; Myers, M. K.

    1978-01-01

    An analytical model is presented to predict noise transmission through elastic plates into a hard-walled rectangular cavity at low frequencies, that is, frequencies up through the first few plate and cavity natural frequencies. One or several nonoverlapping and independently vibrating panels are considered. The effects on noise transmission of different external-pressure excitations, plate boundary conditions, fluid parameters, structural parameters, and geometrical parameters were investigated.

  4. An Empirical Method for Determining the Lunar Gravity Field. Ph.D. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Ferrari, A. J.

    1971-01-01

    A method has been devised to determine the spherical harmonic coefficients of the lunar gravity field. This method consists of a two-step data reduction and estimation process. In the first step, a weighted least-squares empirical orbit determination scheme is applied to Doppler tracking data from lunar orbits to estimate long-period Kepler elements and rates. Each of the Kepler elements is represented by an independent function of time. The long-period perturbing effects of the earth, sun, and solar radiation are explicitly modeled in this scheme. Kepler element variations estimated by this empirical processor are ascribed to the non-central lunar gravitation features. Doppler data are reduced in this manner for as many orbits as are available. In the second step, the Kepler element rates are used as input to a second least-squares processor that estimates lunar gravity coefficients using the long-period Lagrange perturbation equations.

  5. Line-blanketed model stellar atmospheres applied to Sirius. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Fowler, J. W.

    1972-01-01

    The primary goal of this analysis is to determine whether the effects of atomic bound-bound transitions on stellar atmospheric structure can be represented well in models. The investigation is based on an approach which is called the method of artificial absorption edges. The method is described, developed, tested, and applied to the problem of fitting a model stellar atmosphere to Sirius. It is shown that the main features of the entire observed spectrum of Sirius can be reproduced to within the observational uncertainty by a blanketed flux-constant model with T sub eff = 9700 K and Log g = 4.26. The profile of H sub gamma is reproduced completely within the standard deviations of the measurements except near line center, where non-LTE effects are expected to be significant. The equivalent width of H sub gamma, the Paschen slope, the Balmer jump, and the absolute flux at 5550 A all agree with the observed values.

  6. Compressible flows with periodic vortical disturbances around lifting airfoils. Ph.D. Thesis - Notre Dame Univ.

    NASA Technical Reports Server (NTRS)

    Scott, James R.

    1991-01-01

    A numerical method is developed for solving periodic, three-dimensional, vortical flows around lifting airfoils in subsonic flow. The first-order method that is presented fully accounts for the distortion effects of the nonuniform mean flow on the convected upstream vortical disturbances. The unsteady velocity is split into a vortical component which is a known function of the upstream flow conditions and the Lagrangian coordinates of the mean flow, and an irrotational field whose potential satisfies a nonconstant-coefficient, inhomogeneous, convective wave equation. Using an elliptic coordinate transformation, the unsteady boundary value problem is solved in the frequency domain on grids which are determined as a function of the Mach number and reduced frequency. The numerical scheme is validated through extensive comparisons with known solutions to unsteady vortical flow problems. In general, it is seen that the agreement between the numerical and analytical results is very good for reduced frequencies ranging from 0 to 4, and for Mach numbers ranging from .1 to .8. Numerical results are also presented for a wide variety of flow configurations for the purpose of determining the effects of airfoil thickness, angle of attack, camber, and Mach number on the unsteady lift and moment of airfoils subjected to periodic vortical gusts. It is seen that each of these parameters can have a significant effect on the unsteady airfoil response to the incident disturbances, and that the effect depends strongly upon the reduced frequency and the dimensionality of the gust. For a one-dimensional (transverse) or two-dimensional (transverse and longitudinal) gust, the results indicate that airfoil thickness increases the unsteady lift and moment at the low reduced frequencies but decreases it at the high reduced frequencies. The results show that an increase in airfoil Mach number leads to a significant increase in the unsteady lift and moment for the low reduced frequencies, but a significant decrease for the high reduced frequencies.

  7. The effects of context on multidimensional spatial cognitive models. Ph.D. Thesis - Arizona Univ.

    NASA Technical Reports Server (NTRS)

    Dupnick, E. G.

    1979-01-01

    Spatial cognitive models obtained by multidimensional scaling represent cognitive structure by defining alternatives as points in a coordinate space based on relevant dimensions such that interstimulus dissimilarities perceived by the individual correspond to distances between the respective alternatives. The dependence of spatial models on the context of the judgments required of the individual was investigated. Context, which is defined as a perceptual interpretation and cognitive understanding of a judgment situation, was analyzed and classified with respect to five characteristics: physical environment, social environment, task definition, individual perspective, and temporal setting. Four experiments designed to produce changes in the characteristics of context and to test the effects of these changes upon individual cognitive spaces are described with focus on experiment design, objectives, statistical analysis, results, and conclusions. The hypothesis is advanced that an individual can be characterized as having a master cognitive space for a set of alternatives. When the context changes, the individual appears to change the dimension weights to give a new spatial configuration. Factor analysis was used in the interpretation and labeling of cognitive space dimensions.

  8. Physics of Nonmagnetic Relativistic Thermal Plasmas. Ph.D. Thesis - Calif. Univ., San Diego

    NASA Technical Reports Server (NTRS)

    Dermer, C. D.

    1984-01-01

    A detailed treatment of the kinematics of relativistic systems of particles and photons is presented. In the case of a relativistic Maxwell-Boltzmann distribution of particles, the reaction rate and luminosity are written as single integrals over the invariant cross section, and the production spectrum is written as a double integral over the cross section differential in the energy of the produced particles (or photons) in the center-of-momentum system of two colliding particles. The results are applied to the calculation of the annihilation spectrum of a thermal electron-positron plasma, confirming previous numerical and analytic results. Relativistic thermal electron-ion and electron-electron bremsstrahlung are calculated exactly to lowest order, and relativistic thermal electron-positron bremsstrahlung is calculated in an approximate fashion. An approximate treatment of relativistic Comptonization is developed. The question of thermalization of a relativistic plasma is considered. A formula for the energy loss or exchange rate from the interaction of two relativistic Maxwell-Boltzmann plasmas at different temperatures is derived. Application to a stable, uniform, nonmagnetic relativistic thermal plasma is made. Comparison is made with other studies.

  9. Submillimeter wave survey of the galactic plane. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Cheung, L. H.

    1980-01-01

    The survey measured, over virtually the entire galactic plane, the distribution and basic physical conditions of the coolest dust component of the interstellar medium. The instrument designed for observations of extended, low surface brightness continuum emission consisted of a balloon borne, gyro stablized, 1.2 m Cassegrain telescope and a liquid cooled photometer. The design, integration, tests, and flight operation of the survey are presented.

  10. Performance of finned thermal capacitors. Ph.D. Thesis - Texas Univ., Austin

    NASA Technical Reports Server (NTRS)

    Humphries, W. R.

    1974-01-01

    The performance of typical thermal capacitors, both in earth and orbital environments, was investigated. Techniques which were used to make predictions of thermal behavior in a one-g earth environment are outlined. Orbital performance parameters are qualitatively discussed, and those effects expected to be important under zero-g conditions are outlined. A summary of thermal capacitor applications are documentated, along with significant problem areas and current configurations. An experimental program was conducted to determine typical one-g performance, and the physical significance of these data is discussed in detail. Numerical techniques were employed to allow comparison between analytical and experimental data.

  11. Modulation of low energy cosmic rays. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Sari, J. W.

    1972-01-01

    The power spectrum of the interplanetary magnetic field were tested, as well as the power spectrum-cosmic diffusion ray coefficient relation at low energies. A first order perturbation solution of the Fokker-Planck equation governing the diffusion, convection, and adiabatic deceleration of galactic cosmic rays in the solar medium was found to relate intensity fluctuations of low energy cosmic rays to local changes in the propagation parameters. Diffusion coefficients and their day to day variations were calculated from interplanetary magnetic field data obtained by Pioneer 6 in 1965/1966. These are compared to simultaneous observations by IMP 3 of the proton flux in three energy channels (20 to 40, 40 to 60, 60 to 80 MeV).

  12. Active feed array compensation for reflector antenna surface distortions. Ph.D. Thesis - Akron Univ., Ohio

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.

    1988-01-01

    The feasibility of electromagnetic compensation for reflector antenna surface distortions is investigated. The performance characteristics of large satellite communication reflector antenna systems degrade as the reflector surface distorts, mainly due to thermal effects from solar radiation. The technique developed can be used to maintain the antenna boresight directivity and sidelobe level independent of thermal effects on the reflector surface. With the advent of monolithic microwave integrated circuits (MMIC), a greater flexibility in array fed reflector antenna systems can be achieved. MMIC arrays provide independent control of amplitude and phase for each of the many radiating elements in the feed array. By assuming a known surface distortion profile, a simulation study is carried out to examine the antenna performance as a function of feed array size and number of elements. Results indicate that the compensation technique can effectively control boresight directivity and sidelobe level under peak surface distortion in the order of tenth of a wavelength.

  13. The shock process and light element production in supernovae envelopes. Ph.D. Thesis - Chicago Univ.

    NASA Technical Reports Server (NTRS)

    Brown, Lawrence E.; Dearborn, David S.; Schramm, David N.; Larsen, Jon T.; Kurokawa, Shin

    1990-01-01

    Detailed hydrodynamic modeling of the passage of supernova shocks through the hydrogen envelopes of blue and red progenitor stars was carried out to explore the sensitivity to model conditions of light element production (specifically Li-7 and B-11) which was noted by Dearborn, Schramm, Steigman and Truran (1989) (DSST). It is found that, for stellar models with M is less than or approximately 100 M solar mass, current state of the art supernova shocks do not produce significant light element yields by hydrodynamic processes alone. The dependence of this conclusion on stellar models and on shock strengths is explored. Preliminary implications for Galactic evolution of lithium are discussed, and it is suspected that intermediate mass red giant stars may be the most consistent production site for lithium.

  14. High energy hadron-hadron collisions. [Dept. of Physics and Astronomy, Univ. of Georgia, Athens, Georgia

    SciTech Connect

    Chou, T.T.

    1992-01-01

    Results of a study on high energy collisions with the geometrical model are summarized in three parts: (1) the elastic hadron-hadron collision, (2) the inelastic hadron-hadron collision, and (3) e[sup +]e[sup [minus

  15. Elastohydrodynamic lubrication of point contacts. Ph.D. Thesis - Leeds Univ.

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1976-01-01

    A procedure for the numerical solution of the complete, isothermal, elastohydrodynamic lubrication problem for point contacts is given. This procedure calls for the simultaneous solution of the elasticity and Reynolds equations. By using this theory the influence of the ellipticity parameter and the dimensionless speed, load, and material parameters on the minimum and central film thicknesses was investigated. Thirty-four different cases were used in obtaining the fully flooded minimum- and central-film-thickness formulas. Lubricant starvation was also studied. From the results it was possible to express the minimum film thickness for a starved condition in terms of the minimum film thickness for a fully flooded condition, the speed parameter, and the inlet distance. Fifteen additional cases plus three fully flooded cases were used in obtaining this formula. Contour plots of pressure and film thickness in and around the contact have been presented for both fully flooded and starved lubrication conditions.

  16. Citation: Architectural Design. Bahr Vermeer & Haecker: College of Architecture, Univ. of Nebraska.

    ERIC Educational Resources Information Center

    Progressive Architecture, 1979

    1979-01-01

    A P/A architectural design award was given to the University of Nebraska-Lincoln, for a planned expansion of the college of architecture. Two existing buildings will be incorporated in a complex that uses a tightly restricted area at the campus edge. (Author/MLF)

  17. Development of a grid-independent approximate Riemannsolver. Ph.D. Thesis - Michigan Univ.

    NASA Technical Reports Server (NTRS)

    Rumsey, Christopher Lockwood

    1991-01-01

    A grid-independent approximate Riemann solver for use with the Euler and Navier-Stokes equations was introduced and explored. The two-dimensional Euler and Navier-Stokes equations are described in Cartesian and generalized coordinates, as well as the traveling wave form of the Euler equations. The spatial and temporal discretization are described for both explicit and implicit time-marching schemes. The grid-aligned flux function of Roe is outlined, while the 5-wave grid-independent flux function is derived. The stability and monotonicity analysis of the 5-wave model are presented. Two-dimensional results are provided and extended to three dimensions. The corresponding results are presented.

  18. Microgravity vibration isolation technology: Development to demonstration. Ph.D. Thesis - Case Western Reserve Univ.

    NASA Technical Reports Server (NTRS)

    Grodsinsky, Carlos M.

    1993-01-01

    The low gravity environment provided by space flight has afforded the science community a unique area for the study of fundamental and technological sciences. However, the dynamic environment observed on space shuttle flights and predicted for Space Station Freedom has complicated the analysis of prior 'microgravity' experiments and prompted concern for the viability of proposed space experiments requiring long term, low gravity environments. Thus, isolation systems capable of providing significant improvements to this random environment have been developed. This dissertation deals with the design constraints imposed by acceleration sensitive, microgravity experiment payloads in the unique environment of space. A theoretical background for the inertial feedback and feedforward isolation of a payload was developed giving the basis for two experimental active inertial isolation systems developed for the demonstration of these advanced active isolation techniques. A prototype six degree of freedom digital active isolation system was designed and developed for the ground based testing of an actively isolated payload in three horizontal degrees of freedom. A second functionally equivalent system was built for the multi-dimensional testing of an active inertial isolation system in a reduced gravity environment during low gravity aircraft trajectories. These multi-input multi-output control systems are discussed in detail with estimates on acceleration noise floor performance as well as the actual performance acceleration data. The attenuation performance is also given for both systems demonstrating the advantages between inertial and non-inertial control of a payload for both the ground base environment and the low gravity aircraft acceleration environment. A future goal for this area of research is to validate the technical approaches developed to the 0.01 Hz regime by demonstrating a functional active inertial feedforward/feedback isolation system during orbital flight. A NASA IN-STEP flight experiment has been proposed to accomplish this goal, and the expected selection for the IN-STEP program has been set for Jul. of 1993.

  19. [Experimental and theoretical high energy physics program]. [Purdue Univ. , West Lafayette, Indiana

    SciTech Connect

    Finley, J.; Gaidos, J.A.; Loeffler, F.J.; McIlwain, R.L.; Miller, D.H.; Palfrey, T.R.; Shibata, E.I.; Shipsey, I.P.

    1993-04-01

    Experimental and theoretical high-energy physics research at Purdue is summarized in a number of reports. Subjects treated include the following: the CLEO experiment for the study of heavy flavor physics; gas microstrip detectors; particle astrophysics; affine Kac[endash]Moody algebra; nonperturbative mass bounds on scalar and fermion systems due to triviality and vacuum stability constraints; resonance neutrino oscillations; e[sup +]e[sup [minus

  20. TUNL XIX. Annual report, January 1-December 31, 1980. [North Carolina State Univ. activities at TUNL

    SciTech Connect

    1980-12-31

    Research performed by North Carolina State University personnel at TUNL is highlighted in this report, which is actually the complete TUNL progress report for 1980. Studies in the areas of neutron cross sections, neutron polarization, radiative capture, atomic physics and development activities are included. One may expect completed projects to be reported in physics journals or conference proceedings. (RWR)

  1. Satellite Observations of Rapidly Varying Cosmic X-ray Sources. Ph.D. Thesis - Catholic Univ.

    NASA Technical Reports Server (NTRS)

    Maurer, G. S.

    1979-01-01

    The X-ray source data obtained with the high energy celestial X-ray detector on the Orbiting Solar Observatory -8 are presented. The results from the 1977 Crab observation show nonstatistical fluctuations in the pulsed emission and in the structure of the integrated pulse profile which cannot be attributed to any known systematic effect. The Hercules observations presented here provide information on three different aspects of the pulsed X-ray emission: the variation of pulsed flux as a function of the time from the beginning of the ON-state, the variation of pulsed flux as a function of binary phase, and the energy spectrum of the pulse emission.

  2. A numerical study of fundamental shock noise mechanisms. Ph.D. Thesis - Cornell Univ.

    NASA Technical Reports Server (NTRS)

    Meadows, Kristine R.

    1995-01-01

    The results of this thesis demonstrate that direct numerical simulation can predict sound generation in unsteady aerodynamic flows containing shock waves. Shock waves can be significant sources of sound in high speed jet flows, on helicopter blades, and in supersonic combustion inlets. Direct computation of sound permits the prediction of noise levels in the preliminary design stage and can be used as a tool to focus experimental studies, thereby reducing cost and increasing the probability of a successfully quiet product in less time. This thesis reveals and investigates two mechanisms fundamental to sound generation by shocked flows: shock motion and shock deformation. Shock motion is modeled by the interaction of a sound wave with a shock. During the interaction, the shock wave begins to move and the sound pressure is amplified as the wave passes through the shock. The numerical approach presented in this thesis is validated by the comparison of results obtained in a quasi-one dimensional simulation with linear theory. Analysis of the perturbation energy demonstrated for the first time that acoustic energy is generated by the interaction. Shock deformation is investigated by the numerical simulation of a ring vortex interacting with a shock. This interaction models the passage of turbulent structures through the shock wave. The simulation demonstrates that both acoustic waves and contact surfaces are generated downstream during the interaction. Analysis demonstrates that the acoustic wave spreads cylindrically, that the sound intensity is highly directional, and that the sound pressure level increases significantly with increasing shock strength. The effect of shock strength on sound pressure level is consistent with experimental observations of shock noise, indicating that the interaction of a ring vortex with a shock wave correctly models a dominant mechanism of shock noise generation.

  3. Robust fault diagnosis of physical systems in operation. Ph.D. Thesis - Rutgers - The State Univ.

    NASA Technical Reports Server (NTRS)

    Abbott, Kathy Hamilton

    1991-01-01

    Ideas are presented and demonstrated for improved robustness in diagnostic problem solving of complex physical systems in operation, or operative diagnosis. The first idea is that graceful degradation can be viewed as reasoning at higher levels of abstraction whenever the more detailed levels proved to be incomplete or inadequate. A form of abstraction is defined that applies this view to the problem of diagnosis. In this form of abstraction, named status abstraction, two levels are defined. The lower level of abstraction corresponds to the level of detail at which most current knowledge-based diagnosis systems reason. At the higher level, a graph representation is presented that describes the real-world physical system. An incremental, constructive approach to manipulating this graph representation is demonstrated that supports certain characteristics of operative diagnosis. The suitability of this constructive approach is shown for diagnosing fault propagation behavior over time, and for sometimes diagnosing systems with feedback. A way is shown to represent different semantics in the same type of graph representation to characterize different types of fault propagation behavior. An approach is demonstrated that threats these different behaviors as different fault classes, and the approach moves to other classes when previous classes fail to generate suitable hypotheses. These ideas are implemented in a computer program named Draphys (Diagnostic Reasoning About Physical Systems) and demonstrated for the domain of inflight aircraft subsystems, specifically a propulsion system (containing two turbofan systems and a fuel system) and hydraulic subsystem.

  4. Canonical solutions for unsteady flow fields. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Liu, G. C.

    1984-01-01

    The initial value problem of one-dimensional gas-dynamics involving discontinuous, nonuniform initial data is discussed. Canonical solutions which are valid in a small x, t region aroung a discontinuity, and which include the first order effects of nonuniformities in the data, are derived explicitly. The theory is derived by considering a group of elementary piston problems. Solutions with a shock or with a centered expansion wave are worked out individually in order to relate initial flow properties and their gradients to the speed and acceleration of the discontinuity waves. They are then combined to represent the solution of a general initial value problem by regarding the piston path as a contact line. In addition, problems with chemical reaction are discussed in terms of elementary piston problems which involve strong detonation waves, Chapman-Jouguet detonation waves, and deflagration waves.

  5. [Research in theoretical nuclear physics]. [School of Physics and Astronomy, Univ. of Minnesota

    SciTech Connect

    Not Available

    1989-01-01

    Research in progress and plans for future investigations are summarized briefly for the following topics: microscopic cluster or resonating-group theory (multiconfiguration studies, effects of antisymmetrization in the nucleon-nucleus interaction, application to p + [alpha] bremsstrahlung), RPA ground state correlations, collisions of deformed nuclei, energy dependence of charge-pickup reactions, alpha-capture reactions in medium-weight nuclei, quantum hydrodynamic approach to nuclear matter, neutron stars and pulsars, transverse momentum distributions, intermittency and other correlations, photon and dilepton production, electroweak theory at high temperature, and fractional statistics.

  6. Theory and Development of Position-Sensitive Quantum Calorimeters. Degree awarded by Stanford Univ.

    NASA Technical Reports Server (NTRS)

    Figueroa-Feliciano, Enectali; White, Nicholas E. (Technical Monitor)

    2001-01-01

    Quantum calorimeters are being developed as imaging spectrometers for future X-ray astrophysics observatories. Much of the science to be done by these instruments could benefit greatly from larger focal-plane coverage of the detector (without increasing pixel size). An order of magnitude more area will greatly increase the science throughput of these future instruments. One of the main deterrents to achieving this goal is the complexity of the readout schemes involved. We have devised a way to increase the number of pixels from the current baseline designs by an order of magnitude without increasing the number of channels required for readout. The instrument is a high energy resolution, distributed-readout imaging spectrometer called a Position-Sensitive Transition-Edge Sensor (POST). A POST is a quantum calorimeter consisting of two Transition-Edge Sensors (TESS) on the ends of a long absorber capable of one-dimensional imaging spectroscopy. Comparing rise time and energy information from the two TESS, the position of the event in the POST is determined. The energy of the event is inferred from the sum of the two pulses. We have developed a generalized theoretical formalism for distributed-readout calorimeters and apply it to our devices. We derive the noise theory and calculate the theoretical energy resolution of a POST. Our calculations show that a 7-pixel POST with 6 keV saturation energy can achieve 2.3 eV resolution, making this a competitive design for future quantum calorimeter instruments. For this thesis we fabricated 7- and 15-pixel POSTS using Mo/Au TESs and gold absorbers, and moved from concept drawings on scraps of napkins to a 32 eV energy resolution at 1.5 keV, 7-pixel POST calorimeter.

  7. Optimal feedback control for nonlinear control moment gyro systems. Ph.D. Thesis - Virginia Univ.

    NASA Technical Reports Server (NTRS)

    Kyle, R. G.

    1969-01-01

    A study was made, leading to development and analysis of a technique allowing the control moment gyro (CMG) momentum vectors to avoid adverse orientations and thus to provide optimal control for the Apollo Telescope Mount. The technique was formulated in terms of a feedback scheme using a check factor, K, formed as the product of the dot products of the three CMG momentum unit vectors. The parameter K approaches unity for all adverse orientations and was used to initiate a single correction maneuver to rotate the CMG momenta away from a pending adverse orientation and to reduce K to an acceptable value. A digital computer program for ATM simulations was modified to incorporate this correction maneuver and performance was evaluated in simulated cases. Antiparallelism was used as the primary example for the evaluation of the feedback optimization technique.

  8. Early impact basins and the onset of plate tectonics. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Frey, H.

    1977-01-01

    The fundamental crustal dichotomy of the Earth (high and low density crust) was established nearly 4 billion years ago. Therefore, subductable crust was concentrated at the surface of the Earth very early in its history, making possible an early onset for plate tectonics. Simple thermal history calculations spanning 1 billion years show that the basin forming impact thins the lithosphere by at least 25%, and increases the sublithosphere thermal gradients by roughly 20%. The corresponding increase in convective heat transport, combined with the highly fractured nature of the thinned basin lithosphere, suggest that lithospheric breakup or rifting occurred shortly after the formation of the basins. Conditions appropriate for early rifting persisted from some 100,000,000 years following impact. We suggest a very early stage of high temperature, fast spreading "microplate" tectonics, originating before 3.5 billion years ago, and gradually stabilizing over the Archaean into more modern large plate or Wilson Cycle tectonics.

  9. Influence of spinel substrate and over-layer for enhanced SAW and AO properties with KNbO3 thin film.

    PubMed

    Nayak, Ranu; Gupta, Vinay; Sreenivas, Kondepudy

    2003-06-01

    Surface acoustic wave (SAW) propagation characteristics have been studied using modeling calculations for a potassium niobate (KNbO3) thin film-layered structure with (001) and (110) orientation on a single crystal spinel (MgAl2O4) substrate, and a spinel buffer layer on silicon. Variation in the electromechanical coupling and acoustic attenuation has been compared. A significantly high value of coupling factor (k2max = 23%) is obtained for the (001)KNbO3/spinel structure by introducing an optimum thickness of spinel over-layer for potential wide bandwidth SAW device applications. The dispersion characteristics with the (110) KNbO3 orientation indicate an initial peak in the coupling coefficient value (k2max = 8.8%) at a relatively low KNbO3 film thickness that appears attractive for fabricating devices with thinner films. The KNbO3 film with (001) orientation is found attractive for efficient acousto-optic (AO) device application with the formation of a symmetric waveguide structure (spinel(0.5 microm)/KNbO3(1.0 microm)/spinel). A high value of k2 = 23.5% with 50% diffraction efficiency has been obtained for the spinel(0.5 microm)/KNbO3(1.0 microm)/spinel structure at 1 GHz SAW frequency and 633 nm optical wavelength at a very low input drive power of 15.4 mW. PMID:12839169

  10. Summary Report of the First International Symposium on Strain Gauge Balances and Workshop on AoA/Model Deformation Measurement Techniques

    NASA Technical Reports Server (NTRS)

    Tripp, John S.; Tcheng, Ping; Burner, Alpheus W.; Finley, Tom D.

    1998-01-01

    The first International Symposium on Strain Gauge Balances was sponsored under the auspices of the NASA Langley Research Center (LaRC), Hampton, Virginia. Held at the LaRC Reid Conference Center, the Symposium provided an open international forum for presentation, discussion, and exchange of technical information among wind tunnel test technique specialists and strain gauge balance designers. The Symposium also served to initiate organized professional activities among the participating and relevant international technical communities. The program included a panel discussion, technical paper sessions, tours of local facilities, and vendor exhibits. Over 130 delegates were in attendance from 15 countries. A steering committee was formed to plan a second international balance symposium tentatively scheduled to be hosted in the United Kingdom in 1998 or 1999. The Balance Symposium was followed bv the half-day, Workshop on Angle of Attack and Model Deformation on the afternoon of October 25. The thrust of the Workshop was to assess the state of the art in angle of attack (AoA) and model deformation measurement techniques and to discuss future developments.

  11. Summary Report of the First International Symposium on Strain Gauge Balances and Workshop on AoA/Model Deformation Measurement Techniques

    NASA Technical Reports Server (NTRS)

    Tripp, John S.; Tcheng, Ping; Burner, Alpheus W.; Finley, Tom D.

    1999-01-01

    The first International Symposium on Strain Gauge Balances was sponsored under the auspices of the NASA Langley Research Center (LaRC), Hampton, Virginia during October 22-25, 1996. Held at the LaRC Reid Conference Center, the Symposium provided an open international forum for presentation, discussion, and exchange of technical information among wind tunnel test technique specialists and strain gauge balance designers. The Symposium also served to initiate organized professional activities among the participating and relevant international technical communities. The program included a panel discussion, technical paper sessions, tours of local facilities, and vendor exhibits. Over 130 delegates were in attendance from 15 countries. A steering committee was formed to plan a second international balance symposium tentatively scheduled to be hosted in the United Kingdom in 1998 or 1999. The Balance Symposium was followed by the half-day Workshop on Angle of Attack and Model Deformation on the afternoon of October 25. The thrust of the Workshop was to assess the state of the art in angle of attack (AoA) and model deformation measurement techniques and to discuss future developments.

  12. Back-thrusting response of continental collision: Early Cretaceous NW-directed thrusting in the Changle-Nan'ao belt (Southeast China)

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Faure, Michel; Chen, Yan; Ji, Wenbin; Lin, Wei; Wang, Qingchen; Yan, Quanren; Hou, Quanlin

    2015-03-01

    The SE coastal area of the South China Block (SCB) is generally interpreted as a Cretaceous active continental margin due to subduction of the Paleo-Pacific plate beneath the Eurasian plate. There, the NE-SW striking Changle-Nan'ao belt was previously considered as a major strike-slip fault zone with a large displacement accommodating the northward subduction of the Paleo-Pacific plate. Our new field and laboratory investigations document a NW-directed ductile thrust zone that placed gneiss upon Early Cretaceous foliated volcanic rocks. Structural analyses and Anisotropy of Magnetic Susceptibility results indicate that the ductile fabrics in both units are represented by a NE-SW striking foliation and a NW-SE stretching lineation with top-to-the-NW shear sense. This deformation occurred at ca. 130-105 Ma, before the deposition of undeformed (ca. 104 Ma) volcanic rocks, and the intrusion of ca. 90 Ma isotropic plutons. This continent-ward structure is tentatively interpreted as a back-thrust resulting of the collision of the West Philippines microcontinent with the SCB rather than an effect of a simple oceanic subduction.

  13. Effect of sludge-fly ash ceramic particles (SFCP) on synthetic wastewater treatment in an A/O combined biological aerated filter.

    PubMed

    Han, Shuxin; Yue, Qinyan; Yue, Min; Gao, Baoyu; Zhao, Yaqin; Cheng, Wenjing

    2009-02-01

    Novel media-sludge-fly ash ceramic particles (SFCP) employed in an upflow lab-scale A/O BAF were investigated for synthetic wastewater treatment. The influences of hydraulic retention time (HRT), air-liquid ratio (A/L) and recirculation on the removals of chemical oxygen demand (CODcr), ammonia (NH(4)(+)-N) and total nitrogen (TN) were discussed. The optimum operation conditions were obtained as HRT of 2.0 h, A/L of 15:1 and 200% recirculation. Under the optimal conditions, 90% CODcr, more than 98% NH(3)-N and approximately 70% TN were removed. The average consumed volumetric loading rates for CODcr, NH(4)(+)-N and TN with 200% recirculation were 4.06, 0.36 and 0.29 kg(m(3)d)(-1), respectively. The CODcr and TN removal mainly occurred in the anoxic zone, while nitrification was completed at the height of 70 cm from the inlet of the bottom due to a suitable column layout of biological aerated filter (BAF). The characteristics of wastewater and backwashing affected TN removal to a large degree. In addition, the features of media (SFCP) and synthetic wastewater contributed to a strong buffer capacity in the BAF system so that the effluent pH at different media height fluctuated slightly and was insensitive to recirculation. PMID:18828988

  14. Long-term monitoring of the blazars AO 0235+164 and S5 0716+714 in the optical and radio ranges

    NASA Astrophysics Data System (ADS)

    Bychkova, V. S.; Vol'vach, A. E.; Kardashev, N. S.; Larionov, M. G.; Vlasyuk, V. V.; Spiridonova, O. I.; Vol'vach, L. N.; Lähteenmäki, A.; Tornikoski, M.; Aller, M. F.; Aller, H. D.

    2015-09-01

    Long-term, multi-frequency optical and radio monitoring data for the Active Galactic Nuclei (AGNs) AO 0235+164 and S5 0716+714 are used to derive the characteristics of their radiation on time scales from hours to decades. Structure-function and harmonic analyses are carried out to determine the parameters of the radiation of these AGNs and explain their physical characteristics. Periodic components that could be associated with the motion of companions along an orbit in a close binary system of two supermassive black holes are identified. Both of the analysis methods used yield consistent results for the harmonic components. The results obtained are consistent with the idea that we are viewing systems of two supermassive black holes in a stage of their evolution that is close to coalescence. The substantial energy release of these AGNs can be interpreted as dynamical losses arising during the motion of the companion about the common center of gravity in a dense accreting medium, sometimes crossing through the accretion disk.

  15. Superfund explanation of significant difference for the record of decision (EPA region 2): A.O. Polymer, Sparta Township, NJ, September 17, 1996

    SciTech Connect

    1997-03-01

    The Record of Decision (ROD) for the A.O. Polymer Superfund Site (the Site), signed on June 28, 1991, called for the use of a soil vapor extraction system to remove contaminants from the soils that act as the source of groundwater contamination. The groundwater component of the ROD called for extraction of the contaminated groundwater, treatment with a powdered activated carbon treatment (PACT) system, and discharge of the treated water back into the groundwater aquifer. Results from a treatability study performed on the PACT system with groundwater taken from the Site indicate that the effluent from the PACT system exceeds the surface water discharge limitations. In addition, information gathered since the issuance of the ROD has shown that the aquifer does not have sufficient capacity to accept the treatment system effluent without adversely affecting the groundwater plume and surrounding properties. Therefore, the treated groundwater will be discharged to the Wallkill River located 500 feet southeast of the Site. Further, air stripping will be used instead of PACT to remove contaminants from the groundwater.

  16. New Extinction and Mass Estimates from Optical Photometry of the Very Low Mass Brown Dwarf Companion CT Chamaeleontis B with the Magellan AO System

    NASA Astrophysics Data System (ADS)

    Wu, Ya-Lin; Close, Laird M.; Males, Jared R.; Barman, Travis S.; Morzinski, Katie M.; Follette, Katherine B.; Bailey, Vanessa; Rodigas, Timothy J.; Hinz, Philip; Puglisi, Alfio; Xompero, Marco; Briguglio, Runa

    2015-03-01

    We used the Magellan adaptive optics system and its VisAO CCD camera to image the young low mass brown dwarf companion CT Chamaeleontis B for the first time at visible wavelengths. We detect it at r', i', z', and YS . With our new photometry and T eff ~ 2500 K derived from the shape of its K-band spectrum, we find that CT Cha B has AV = 3.4 ± 1.1 mag, and a mass of 14-24 MJ according to the DUSTY evolutionary tracks and its 1-5 Myr age. The overluminosity of our r' detection indicates that the companion has significant H? emission and a mass accretion rate ~6 × 10-10 M ? yr-1, similar to some substellar companions. Proper motion analysis shows that another point source within 2'' of CT Cha A is not physical. This paper demonstrates how visible wavelength adaptive optics photometry (r', i', z', YS ) allows for a better estimate of extinction, luminosity, and mass accretion rate of young substellar companions. This paper includes data gathered with the 6.5 m Magellan Clay Telescope at Las Campanas Observatory, Chile.

  17. Comparative Effectiveness of Di'ao Xin Xue Kang Capsule and Compound Danshen Tablet in Patients With Symptomatic Chronic Stable Angina

    PubMed Central

    Yu, Yanan; Hu, Siyuan; Li, Guoxin; Xue, Jie; Li, Zhuoming; Liu, Xiangling; Yang, Xiyan; Dong, Bo; Wang, Donghai; Wang, Xiaofeng; Liu, Shurong; Liu, Jun; Chen, Bingwei; Wang, Liying; Liu, Songshan; Chen, Qiguang; Shen, Chunti; Wang, Zhong; Wang, Yongyan

    2014-01-01

    A high proportion of patients with stable angina remains symptomatic despite multiple treatment options. Di'ao Xinxuekang (XXK) capsule and Compound Danshen (CDS) tablet have been approved for treating angina pectoris for more than 20 years in China. We compare the anti-anginal effectiveness of XXK capsule and CDS tablet in patients with symptomatic chronic stable angina. A randomized, multicenter, double-blind, parallel-group, superiority trial was conducted in 4 study sites. 733 patients with symptomatic chronic stable angina were included in the full analysis set. The primary outcomes were the proportion of patients who were angina-free and the proportion of patients with normal electrocardiogram (ECG) recordings during 20 weeks treatment. Compared with CDS, XXK significantly increased the proportion of angina-free patients, but no significant difference was noted in the proportion of patients with normal ECG recordings. Weekly angina frequency and nitroglycerin use were significantly reduced with XXK versus CDS at week 20. Moreover, XXK also improved the quality of life of angina patients as measured by the SAQ score and Xueyu Zheng (a type of TCM syndrome) score. We demonstrate that XXK capsule is more effective for attenuating anginal symptoms and improving quality of life in patients with symptomatic chronic stable angina, compared with CDS tablet. PMID:25394847

  18. Processes controlling the seasonal and spatial variations in sulfate profiles in the pore water of the sediments surrounding Qi'ao Island, Pearl River Estuary, Southern China

    NASA Astrophysics Data System (ADS)

    Wu, Zijun; Zhou, Huaiyang; Ren, Dezhang; Gao, Hang; Li, Jiangtao

    2015-04-01

    Marine sediments are the main sink for seawater sulfate and bacterial sulfate reduction is a major component of the global sulfur cycle. Nevertheless, the factors controlling sulfate reduction in the coastal estuary sediments that undergo spatial and temporal variations are still not fully understood. In this study, we measured the concentrations of SO42-, Cl-, CH4, and DIC, and the ?13C of DIC in the pore water of five sampling stations surrounding the Qi'ao Island, Pearl River Estuary, Southern China during the dry season in November 2011 and during the wet season in May 2012. The results showed that the dilution-mixing of the Pearl River with low-concentration sulfate significantly affects the downcore profiles of the sulfate concentrations in the pore water of these estuary sediments. During the wet season, the dilution-mixing of the layers from the top of the sediments to a depth of 14-18 cm occurred at the different sampling stations. In this layer, the sulfate reduction is not appreciable based on the plot of the pore water Cl- and SO42-. Below the dilution-mixing layers, however, sulfate reduction that is driven by the anaerobic oxidation of methane (AOM) occurs. In our comparison, it appeared that the AOM played more important role in the consumption of the pore water sulfate in May 2012 than in November 2011. Meanwhile, we observed a relatively good correlation (r2=0.64) between the depth of the sulfate-methane interface (SMI) and the sulfate concentration in the pore water of the top sediments in dry season, indicating that the pore water sulfate concentration appears to be a primary controlling factor for the depth of the SMI in this estuary. These results highlight the need for an integrated analysis of the hydrologically driven the variations in the sulfate profiles to improve our understanding of the biogeochemical cycling of C, Fe and S and their budgets in estuarine environments.

  19. A measurement of the systematic astrometric error in GeMS and the short-term astrometric precision in ShaneAO

    NASA Astrophysics Data System (ADS)

    Ammons, S. M.; Neichel, Benoit; Lu, Jessica; Gavel, Donald T.; Srinath, Srikar; McGurk, Rosalie; Rudy, Alex; Rockosi, Connie; Marois, Christian; Macintosh, Bruce; Savransky, Dmitry; Galicher, Raphael; Bendek, Eduardo; Guyon, Olivier; Marin, Eduardo; Garrel, Vincent; Sivo, Gaetano

    2014-08-01

    We measure the long-term systematic component of the astrometric error in the GeMS MCAO system as a function of field radius and Ks magnitude. The experiment uses two epochs of observations of NGC 1851 separated by one month. The systematic component is estimated for each of three field of view cases (15'' radius, 30'' radius, and full field) and each of three distortion correction schemes: 8 DOF/chip + local distortion correction (LDC), 8 DOF/chip with no LDC, and 4 DOF/chip with no LDC. For bright, unsaturated stars with 13 < Ks < 16, the systematic component is < 0.2, 0.3, and 0.4 mas, respectively, for the 15'' radius, 30'' radius, and full field cases, provided that an 8 DOF/chip distortion correction with LDC (for the full-field case) is used to correct distortions. An 8 DOF/chip distortion-correction model always outperforms a 4 DOF/chip model, at all field positions and magnitudes and for all field-of-view cases, indicating the presence of high-order distortion changes. Given the order of the models needed to correct these distortions (~8 DOF/chip or 32 degrees of freedom total), it is expected that at least 25 stars per square arcminute would be needed to keep systematic errors at less than 0.3 milliarcseconds for multi-year programs. We also estimate the short-term astrometric precision of the newly upgraded Shane AO system with undithered M92 observations. Using a 6-parameter linear transformation to register images, the system delivers ~0.3 mas astrometric error over short-term observations of 2-3 minutes.

  20. On the Location of the gamma-Ray Outburst Emission in the BL Lacertae Object AO 0235 + 164 Through Observations Across the Electromagnetic Spectrum

    NASA Technical Reports Server (NTRS)

    Agudo, Ivan; Marscher, Alan P.; Jorstad, Svetlana G.; Larionov, Valeri M.; Gomez, Jose L.; Laehteenmaeki, Anne; Smith, Paul S.; Nilsson, Kari; Readhead, Anthony C. S.; Aller, Margo F.; Heidt, Jochien; Gurwell, Mark; Thum, Clemens; Wehrle, Ann E.; Nikolashvili, Maria G.; Aller, Hugh D.; Benitez, Erika; Blinov, Dmitriy A.; Hagen-Thorn, Vladimir A.; Hiriart, David; Jannuzi, Buell T.; Joshi, Manasvita; Kimeridze, Givi N.; Kurtanidze, Omar M.; Kurtanidze, Sofia O.

    2011-01-01

    We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and gamma-ray wavelengths of the BL Lacertae object AO 0235+164. We analyze the timing of multi-waveband variations in the flux and linear polarization, as well as changes in Very Long Baseline Array images at A = 7 mm with approx.0.15 milliarcsec resolution. The association of the events at different wavebands is confirmed at high statistical significance by probability arguments and Monte Carlo simulations. A series of sharp peaks in optical linear polarization, as well as a pronounced maximum in the 7 mm polarization of a superluminal jet knot, indicate rapid fluctuations in the degree of ordering of the magnetic field. These results lead us to conclude that the outburst occurred in the jet both in the quasi-stationary "core" and in the superluminal knot, both parsecs downstream of the supermassive black hole. We interpret the outburst as a consequence of the propagation of a disturbance, elongated along the line of sight by light-travel time delays, that passes through a standing recollimation shock in the core and propagates down the jet to create the superluminal knot. The multi-wavelength light curves vary together on long timescales (months/ years), but the correspondence is poorer on shorter timescales. This, as well as the variability of the polarization and the dual location of the outburst, agrees with the expectations of a multi-zone emission model in which turbulence plays a major role in modulating the synchrotron and inverse Compton fluxes.

  1. On the Location of the ?-Ray Outburst Emission in the BL Lacertae Object AO 0235+164 Through Observations Across the Electromagnetic Spectrum

    NASA Astrophysics Data System (ADS)

    Agudo, Iván; Marscher, Alan P.; Jorstad, Svetlana G.; Larionov, Valeri M.; Gómez, José L.; Lähteenmäki, Anne; Smith, Paul S.; Nilsson, Kari; Readhead, Anthony C. S.; Aller, Margo F.; Heidt, Jochen; Gurwell, Mark; Thum, Clemens; Wehrle, Ann E.; Nikolashvili, Maria G.; Aller, Hugh D.; Benítez, Erika; Blinov, Dmitriy A.; Hagen-Thorn, Vladimir A.; Hiriart, David; Jannuzi, Buell T.; Joshi, Manasvita; Kimeridze, Givi N.; Kurtanidze, Omar M.; Kurtanidze, Sofia O.; Lindfors, Elina; Molina, Sol N.; Morozova, Daria A.; Nieppola, Elina; Olmstead, Alice R.; Reinthal, Riho; Roca-Sogorb, Mar; Schmidt, Gary D.; Sigua, Lorand A.; Sillanpää, Aimo; Takalo, Leo; Taylor, Brian; Tornikoski, Merja; Troitsky, Ivan S.; Zook, Alma C.; Wiesemeyer, Helmut

    2011-07-01

    We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and ?-ray wavelengths of the BL Lacertae object AO 0235+164. We analyze the timing of multi-waveband variations in the flux and linear polarization, as well as changes in Very Long Baseline Array images at ? = 7 mm with ~0.15 milliarcsec resolution. The association of the events at different wavebands is confirmed at high statistical significance by probability arguments and Monte Carlo simulations. A series of sharp peaks in optical linear polarization, as well as a pronounced maximum in the 7 mm polarization of a superluminal jet knot, indicate rapid fluctuations in the degree of ordering of the magnetic field. These results lead us to conclude that the outburst occurred in the jet both in the quasi-stationary "core" and in the superluminal knot, both parsecs downstream of the supermassive black hole. We interpret the outburst as a consequence of the propagation of a disturbance, elongated along the line of sight by light-travel time delays, that passes through a standing recollimation shock in the core and propagates down the jet to create the superluminal knot. The multi-wavelength light curves vary together on long timescales (months/years), but the correspondence is poorer on shorter timescales. This, as well as the variability of the polarization and the dual location of the outburst, agrees with the expectations of a multi-zone emission model in which turbulence plays a major role in modulating the synchrotron and inverse Compton fluxes.

  2. Using UPLC-QTOF-MS to analyze the chemical changes between traditional and dispensing granule decoctions of San-Ao-Tang.

    PubMed

    Ma, Chunhua; Qian, Yefei; Fan, Xinsheng; Shang, ErXin; Yao, Xin; Ma, Shiping

    2014-04-01

    In the present study, a chemical profiling approach based on ultra-performance liquid chromatography coupled with photodiode array detection and time-of-flight mass spectrometry (UPLC-PDA-TOF-MS) was proposed to rapidly evaluate the chemical consistency between traditional and dispensing granule decoctions of traditional medicine combinatorial formulae and validated using San-Ao-Tang (SAT) as a model combinatorial formula. SAT is an effective traditional Chinese medicine, which is usually used in treating asthma and other diseases of the respiratory system. Two decoctions were prepared: traditional decoction, which is a water extract of three mixed constituent herbs of SAT; and dispensing granule decoction, which is a mixed water extract of each individual herb of SAT. Batches of these two decoction samples were subjected to UPLC-PDA-TOF-MS analysis and the data sets of t(R)-m/z pairs, ion intensities and sample codes were processed with supervised orthogonal partial least squared discriminant analysis to holistically compare their differences. Once a clear classification trend was found in the score plot, further statistics were performed to generate points at the two ends of S, and the components that correlated to these ions were regarded as the most changed components during decoction of the combinatorial formula. The changed components were identified by comparing the mass/ultraviolet spectra and retention times with those of reference compounds and/or tentatively assigned by matching empirical molecular formulae with those of the known compounds published in the literature. Using the proposed approach, global chemical differences were found between traditional and dispensing granule decoctions, like ephedrine, pseudoephedrine, norpseudoephedrine, licorice saponine H2, licorice saponine G2 and amygdalin. PMID:23572319

  3. Temperature dependence of alkali-metal rattling dynamics in the ?-pyrochlores, AOs2O6 (A = K, Rb, Cs), from MD simulation.

    PubMed

    Shoko, E; Peterson, V K; Kearley, G J

    2014-06-11

    We investigate the temperature response of the alkali-metal rattling modes in ?-pyrochlores, AOs2O6 (A = K, Rb, Cs), from the results of ab initio molecular dynamics (MD) simulations performed at 20?K, 100?K and 300?K. Our results show that the temperature response of the T1u mode is clearly different from that of the T2g mode for all three pyrochlores. In this regard, two features are of particular note for both K and Rb; (1) the T1u mode exhibits a distinctly stronger softening response with decreasing temperature compared to the T2g mode, and (2) the T1u mode becomes stronger and sharper with decreasing temperature. These two findings suggest that the T1u mode is significantly more anharmonic and sensitive to the cage dynamics than the T2g mode. Examination of the local potentials around the alkali-metal atoms reveals that K has the flattest and most anharmonic potential at all temperatures while Cs exhibits the narrowest potential. The temperature dependence of the local potentials reveals that, for K, the potential at a higher temperature is not a simple extrapolation to higher energy of that at a lower temperature. Instead, we find significant reconstruction of the potential at different temperatures. Finally, we explore the temperature response of the coupling between the alkali metals and find a complex temperature dependence which suggests that the origin of the coupling may be more complex than a pure Coulomb interaction. We also find an unexpected increase in the static disorder of the system at low temperatures for the K and Rb pyrochlores. PMID:24832480

  4. ON THE LOCATION OF THE {gamma}-RAY OUTBURST EMISSION IN THE BL LACERTAE OBJECT AO 0235+164 THROUGH OBSERVATIONS ACROSS THE ELECTROMAGNETIC SPECTRUM

    SciTech Connect

    Agudo, Ivan; Gomez, Jose L.; Marscher, Alan P.; Jorstad, Svetlana G.; Larionov, Valeri M.; Blinov, Dmitriy A.; Hagen-Thorn, Vladimir A.; Laehteenmaeki, Anne; Smith, Paul S.; Nilsson, Kari; Readhead, Anthony C. S.; Aller, Margo F.; Aller, Hugh D.; Heidt, Jochen; Gurwell, Mark; Thum, Clemens; Wehrle, Ann E.; Nikolashvili, Maria G.; BenItez, Erika; Hiriart, David

    2011-07-01

    We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and {gamma}-ray wavelengths of the BL Lacertae object AO 0235+164. We analyze the timing of multi-waveband variations in the flux and linear polarization, as well as changes in Very Long Baseline Array images at {lambda} = 7 mm with {approx}0.15 milliarcsec resolution. The association of the events at different wavebands is confirmed at high statistical significance by probability arguments and Monte Carlo simulations. A series of sharp peaks in optical linear polarization, as well as a pronounced maximum in the 7 mm polarization of a superluminal jet knot, indicate rapid fluctuations in the degree of ordering of the magnetic field. These results lead us to conclude that the outburst occurred in the jet both in the quasi-stationary 'core' and in the superluminal knot, both parsecs downstream of the supermassive black hole. We interpret the outburst as a consequence of the propagation of a disturbance, elongated along the line of sight by light-travel time delays, that passes through a standing recollimation shock in the core and propagates down the jet to create the superluminal knot. The multi-wavelength light curves vary together on long timescales (months/years), but the correspondence is poorer on shorter timescales. This, as well as the variability of the polarization and the dual location of the outburst, agrees with the expectations of a multi-zone emission model in which turbulence plays a major role in modulating the synchrotron and inverse Compton fluxes.

  5. Aquecimento alfvênico viscoso-resistivo em discos de acresção ao redor de estrelas T Tauri clássicas

    NASA Astrophysics Data System (ADS)

    Santana, W. M.; Vasconcelos, M. J.

    2003-08-01

    Com a crescente disponibilidade de dados observacionais sobre estrelas T Tauri, a busca por modelos mais precisos vem se tornando cada vez maior. Estes modelos devem explicar, entre outras coisas, o mecanismo dissipativo responsável pelo transporte de momento angular no disco de acresção que acredita-se, circunda estas estrelas. O mecanismo mais viável, do ponto de vista teórico, é uma instabilidade MHD conhecida como "instabilidade magnetorotacional ou Balbus-Hawley" (IBH). Esta instabilidade veio mostrar que o campo magnético desempenha um papel importante na evolução destes objetos mas requer, no entanto, um acoplamento mínimo entre o gás e o campo magnético no disco que não é atingido para os valores de temperatura obtidos do modelo padrão. Contudo, alguns mecanismos de aquecimento para o disco precisam ser examinados. Neste trabalho, propomos a dissipação de ondas Alfvén como uma fonte de aquecimento para o disco. Se o gás apresentar uma condutividade elétrica finita e viscosidade, teremos um tipo de amortecimento para as ondas denominado amortecimento viscoso-resistivo que será aqui considerado. Este mecanismo é aplicado ao modelo de disco em camadas. Calculam-se as taxas de aquecimento Alfvênico, a temperatura efetiva do disco bem como as taxas de ionização decorrentes deste aquecimento e do aquecimento gerado pela absorção de raios cósmicos. Comparações com os dados observacionais de Kitamura et. al. (2001) são efetuadas, ressaltando-se os pontos comuns entre suas observações e nossos dados teóricos.

  6. Radio-to-UV monitoring of AO 0235+164 by the WEBT and Swift during the 2006-2007 outburst

    NASA Astrophysics Data System (ADS)

    Raiteri, C. M.; Villata, M.; Larionov, V. M.; Aller, M. F.; Bach, U.; Gurwell, M.; Kurtanidze, O. M.; Lähteenmäki, A.; Nilsson, K.; Volvach, A.; Aller, H. D.; Arkharov, A. A.; Bachev, R.; Berdyugin, A.; Böttcher, M.; Buemi, C. S.; Calcidese, P.; Cozzi, E.; di Paola, A.; Dolci, M.; Fan, J. H.; Forné, E.; Foschini, L.; Gupta, A. C.; Hagen-Thorn, V. A.; Hooks, L.; Hovatta, T.; Joshi, M.; Kadler, M.; Kimeridze, G. N.; Konstantinova, T. S.; Kostov, A.; Krichbaum, T. P.; Lanteri, L.; Larionova, L. V.; Lee, C.-U.; Leto, P.; Lindfors, E.; Montagni, F.; Nesci, R.; Nieppola, E.; Nikolashvili, M. G.; Ohlert, J.; Oksanen, A.; Ovcharov, E.; Pääkkönen, P.; Pasanen, M.; Pursimo, T.; Ros, J. A.; Semkov, E.; Sigua, L. A.; Smart, R. L.; Strigachev, A.; Takalo, L. O.; Torii, K.; Torniainen, I.; Tornikoski, M.; Trigilio, C.; Tsunemi, H.; Umana, G.; Valcheva, A.

    2008-03-01

    Context: The blazar AO 0235+164 was claimed to show a quasi-periodic behaviour in the radio and optical bands in the past, with the main outbursts repeating every 5-6 years. However, the predicted 2004 outburst did not occur, and further analysis suggested a longer time scale, according to which the next event would have occurred in the 2006-2007 observing season. Moreover, an extra emission component contributing to the UV and soft X-ray flux was detected, whose nature is not yet clear. An optical outburst was observed in late 2006-early 2007, which triggered a Whole Earth Blazar Telescope (WEBT) campaign as well as target of opportunity (ToO) observations by the Swift satellite. Aims: In this paper, we present the radio-to-optical data taken by the WEBT together with the UV data acquired by the UltraViolet and Optical Telescope (UVOT) instrument onboard Swift to investigate both the outburst behaviour at different wavelengths and the nature of the extra emission component. Methods: Multifrequency light curves have been assembled with data from 27 observatories; optical and UV fluxes have been cleaned from the contamination of the southern active galactic nucleus (AGN). We have analysed spectral energy distributions at different epochs, corresponding to different brightness states; extra absorption by the foreground galaxy has been taken into account. Results: We found the optical outburst to be as strong as the big outbursts of the past: starting from late September 2006, a brightness increase of ~5 mag led to the outburst peak in February 19-21, 2007. We also observed an outburst at mm and then at cm wavelengths, with an increasing time delay going toward lower frequencies during the rising phase. Cross-correlation analysis indicates that the 1 mm and 37 GHz flux variations lagged behind the R-band ones by about 3 weeks and 2 months, respectively. These short time delays suggest that the corresponding jet emitting regions are only slightly separated and/or misaligned. In contrast, during the outburst decreasing phase the flux faded contemporaneously at all cm wavelengths. This abrupt change in the emission behaviour may suggest the presence of some “shutdown” mechanism of intrinsic or geometric nature. The behaviour of the UV flux closely follows the optical and near-IR one. By separating the synchrotron and extra component contributions to the UV flux, we found that they correlate, which suggests that the two emissions have a common origin.

  7. Multifrequency variability of the blazar AO 0235+164. The WEBT campaign in 2004-2005 and long-term SED analysis

    NASA Astrophysics Data System (ADS)

    Raiteri, C. M.; Villata, M.; Kadler, M.; Ibrahimov, M. A.; Kurtanidze, O. M.; Larionov, V. M.; Tornikoski, M.; Boltwood, P.; Lee, C.-U.; Aller, M. F.; Romero, G. E.; Aller, H. D.; Araudo, A. T.; Arkharov, A. A.; Bach, U.; Barnaby, D.; Berdyugin, A.; Buemi, C. S.; Carini, M. T.; Carosati, D.; Cellone, S. A.; Cool, R.; Dolci, M.; Efimova, N. V.; Fuhrmann, L.; Hagen-Thorn, V. A.; Holcomb, M.; Ilyin, I.; Impellizzeri, V.; Ivanidze, R. Z.; Kapanadze, B. Z.; Kerp, J.; Konstantinova, T. S.; Kovalev, Y. Y.; Kovalev, Yu. A.; Kraus, A.; Krichbaum, T. P.; Lähteenmäki, A.; Lanteri, L.; Leto, P.; Lindfors, E.; Mattox, J. R.; Napoleone, N.; Nikolashvili, M. G.; Nilsson, K.; Ohlert, J.; Papadakis, I. E.; Pasanen, M.; Poteet, C.; Pursimo, T.; Ros, E.; Sigua, L. A.; Smith, S.; Takalo, L. O.; Trigilio, C.; Tröller, M.; Umana, G.; Ungerechts, H.; Walters, R.; Witzel, A.; Xilouris, E.

    2006-12-01

    Aims.A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by the Whole Earth Blazar Telescope (WEBT) in 2003-2005 to study the variability properties of the source. Methods: .Monitoring observations were carried out at cm and mm wavelengths, and in the near-IR and optical bands, while three pointings by the XMM-Newton satellite provided information on the X-ray and UV emission. Results: .We present the data acquired during the second observing season, 2004-2005, by 27 radio-to-optical telescopes. The ~2600 data points collected allow us to trace the low-energy behaviour of the source in detail, revealing an increased near-IR and optical activity with respect to the previous season. Increased variability is also found at the higher radio frequencies, down to ~15 GHz, but not at the lower ones. While the X-ray (and optical) light curves obtained during the XMM-Newton pointings reveal no significant short-term variability, the simultaneous intraday radio observations with the 100 m telescope at Effelsberg show flux-density changes at 10.5 GHz, which are more likely due to a combination of intrinsic and extrinsic processes. Conclusions: .The radio (and optical) outburst predicted to peak around February-March 2004 on the basis of the previously observed 5-6 yr quasi-periodicity did not occur. The analysis of the optical light curves reveals now a longer characteristic time scale of variability of ~8 yr, which is also present in the radio data. The spectral energy distributions corresponding to the XMM-Newton observations performed during the WEBT campaign are compared with those pertaining to previous pointings of X-ray satellites. Bright, soft X-ray spectra can be described in terms of an extra component, which appears also when the source is faint through a hard UV spectrum and a curvature of the X-ray spectrum. Finally, there might be a correlation between the X-ray and optical bright states with a long time delay of about 5 yr, which would require a geometrical interpretation.

  8. Application of 'Six Sigma{sup TM}' and 'Design of Experiment' for Cementation - Recipe Development for Evaporator Concentrate for NPP Ling AO, Phase II (China) - 12555

    SciTech Connect

    Fehrmann, Henning; Perdue, Robert

    2012-07-01

    Cementation of radioactive waste is a common technology. The waste is mixed with cement and water and forms a stable, solid block. The physical properties like compression strength or low leach ability depends strongly on the cement recipe. Due to the fact that this waste cement mixture has to fulfill special requirements, a recipe development is necessary. The Six Sigma{sup TM}' DMAIC methodology, together with the Design of experiment (DoE) approach, was employed to optimize the process of a recipe development for cementation at the Ling Ao nuclear power plant (NPP) in China. The DMAIC offers a structured, systematical and traceable process to derive test parameters. The DoE test plans and statistical analysis is efficient regarding the amount of test runs and the benefit gain by getting a transfer function. A transfer function enables simulation which is useful to optimize the later process and being responsive to changes. The DoE method was successfully applied for developing a cementation recipe for both evaporator concentrate and resin waste in the plant. The key input parameters were determined, evaluated and the control of these parameters were included into the design. The applied Six Sigma{sup TM} tools can help to organize the thinking during the engineering process. Data are organized and clearly presented. Various variables can be limited to the most important ones. The Six Sigma{sup TM} tools help to make the thinking and decision process trace able. The tools can help to make data driven decisions (e.g. C and E Matrix). But the tools are not the only golden way. Results from scoring tools like the C and E Matrix need close review before using them. The DoE is an effective tool for generating test plans. DoE can be used with a small number of tests runs, but gives a valuable result from an engineering perspective in terms of a transfer function. The DoE prediction results, however, are only valid in the tested area. So a careful selection of input parameter and their limits for setting up a DoE is very important. An extrapolation of results is not recommended because the results are not reliable out of the tested area. (authors)

  9. Magellan Adaptive Optics First-light Observations of the Exoplanet β Pic b. II. 3-5 μm Direct Imaging with MagAO+Clio, and the Empirical Bolometric Luminosity of a Self-luminous Giant Planet

    NASA Astrophysics Data System (ADS)

    Morzinski, Katie M.; Males, Jared R.; Skemer, Andy J.; Close, Laird M.; Hinz, Phil M.; Rodigas, T. J.; Puglisi, Alfio; Esposito, Simone; Riccardi, Armando; Pinna, Enrico; Xompero, Marco; Briguglio, Runa; Bailey, Vanessa P.; Follette, Katherine B.; Kopon, Derek; Weinberger, Alycia J.; Wu, Ya-Lin

    2015-12-01

    Young giant exoplanets are a unique laboratory for understanding cool, low-gravity atmospheres. A quintessential example is the massive extrasolar planet β Pic b, which is 9 AU from and embedded in the debris disk of the young nearby A6V star β Pictoris. We observed the system with first light of the Magellan Adaptive Optics (MagAO) system. In Paper I we presented the first CCD detection of this planet with MagAO+VisAO. Here we present four MagAO+Clio images of β Pic b at 3.1 μm, 3.3 μm, L‧, and {M}\\prime , including the first observation in the fundamental CH4 band. To remove systematic errors from the spectral energy distribution (SED), we re-calibrate the literature photometry and combine it with our own data, for a total of 22 independent measurements at 16 passbands from 0.99 to 4.8 μm. Atmosphere models demonstrate the planet is cloudy but are degenerate in effective temperature and radius. The measured SED now covers >80% of the planet's energy, so we approach the bolometric luminosity empirically. We calculate the luminosity by extending the measured SED with a blackbody and integrating to find log({{L}}{bol}/{{L}}⊙ ) \\=\\-3.78+/- 0.03. From our bolometric luminosity and an age of 23 ± 3 Myr, hot-start evolutionary tracks give a mass of 12.7 ± 0.3 {{M}}{Jup}, radius of 1.45 ± 0.02 {{R}}{Jup}, and Teff of 1708 ± 23 K (model-dependent errors not included). Our empirically determined luminosity is in agreement with values from atmospheric models (typically -3.8 dex), but brighter than values from the field-dwarf bolometric correction (typically -3.9 dex), illustrating the limitations in comparing young exoplanets to old brown dwarfs.

  10. Prevalence of Pediculus humanus capitis among school girls of Chuang-Wei and Nan-Ao Districts in I-Lan County and Man-Chow District in Ping-Tung County, Taiwan.

    PubMed

    Chao, D; Liu, H Y; Fan, P C

    1981-03-01

    By using the naked eye examination and comb method, a field survey and combing collection of head louse (Pediculus humanus capitis) among school girls in three different area (Man-Chow, Nan-Ao and Chuang-Wei) of Taiwan were performed from July 1979 to February, 1980. The general infestation rate of head louse was 39.8% (or 998/2,509). In the primary schools, comparatively, the rate at Man-Chow (66.7%) was highest, the next at Nan-Ao (55.4%) and the lowest at Chuang-Wei (39.4%). While in the junior high schools, the rate was apparently higher at Nan-Ao (38.4%) than that at Man-Chow (15.6%) and Chang-Wei (12.0%). The highest rate in the primary schools was found in 3rd graders except at Chuang-Wei in 5th graders. The corresponding figure in the junior high schools was found in 1st graders except at Nan-Ao in 2nd graders. Of 774 infested girls studied, according to the number of lice per infested girl, the percentages of infestation in the 5 groups were: the very light (nits only) 54.5, light (1-10) 38.5, moderate (11-50) 6.5, heavy (51-100) 0.4 and very heavy (over 100) 0.1 respectively. Of 2,178 head lice examined, 53.0% was nymphs; 28.7% females; 18.2% males. The average number of head louse in each infested girl 6.2. PMID:7261698

  11. The WEBT campaign to observe AO 0235+16 in the 2003-2004 observing season. Results from radio-to-optical monitoring and XMM-Newton observations

    NASA Astrophysics Data System (ADS)

    Raiteri, C. M.; Villata, M.; Ibrahimov, M. A.; Larionov, V. M.; Kadler, M.; Aller, H. D.; Aller, M. F.; Kovalev, Y. Y.; Lanteri, L.; Nilsson, K.; Papadakis, I. E.; Pursimo, T.; Romero, G. E.; Teräsranta, H.; Tornikoski, M.; Arkharov, A. A.; Barnaby, D.; Berdyugin, A.; Böttcher, M.; Byckling, K.; Carini, M. T.; Carosati, D.; Cellone, S. A.; Ciprini, S.; Combi, J. A.; Crapanzano, S.; Crowe, R.; di Paola, A.; Dolci, M.; Fuhrmann, L.; Gu, M.; Hagen-Thorn, V. A.; Hakala, P.; Impellizzeri, V.; Jorstad, S.; Kerp, J.; Kimeridze, G. N.; Kovalev, Yu. A.; Kraus, A.; Krichbaum, T. P.; Kurtanidze, O. M.; Lähteenmäki, A.; Lindfors, E.; Mingaliev, M. G.; Nesci, R.; Nikolashvili, M. G.; Ohlert, J.; Orio, M.; Ostorero, L.; Pasanen, M.; Pati, A.; Poteet, C.; Ros, E.; Ros, J. A.; Shastri, P.; Sigua, L. A.; Sillanpää, A.; Smith, N.; Takalo, L. O.; Tosti, G.; Vasileva, A.; Wagner, S. J.; Walters, R.; Webb, J. R.; Wills, W.; Witzel, A.; Xilouris, E.

    2005-07-01

    A multiwavelength campaign to observe the BL Lac object AO 0235+16 (z=0.94) was set up by the Whole Earth Blazar Telescope (WEBT) collaboration during the observing seasons 2003-2004 and 2004-2005, involving radio, near-IR and optical photometric monitoring, VLBA monitoring, optical spectral monitoring, and three pointings by the XMM-Newton satellite. Here we report on the results of the first season, which involved the participation of 24 optical and near-IR telescopes and 4 radio telescopes, as well as the first XMM-Newton pointing, which occurred on January 18-19, 2004. Unpublished data from previous epochs were also collected (from 5 optical-NIR and 3 radio telescopes), in order to fill the gap between the end of the period presented in Raiteri et al. (2001) and the start of the WEBT campaign. The contribution of the southern AGN, 2 arcsec distant from the source, is taken into account. It is found to especially affect the blue part of the optical spectrum when the source is faint. In the optical and near-IR the source has been very active in the last 3 years, although it has been rather faint most of the time, with noticeable variations of more than a magnitude over a few days. In contrast, in the radio bands it appears to have been “quiescent” since early 2000. The major radio (and optical) outburst predicted to peak around February-March 2004 (with a six month uncertainty) has not occurred yet. When comparing our results with the historical light curves, two different behaviours seem to characterize the optical outbursts: only the major events present a radio counterpart. The X-ray spectra obtained by the three EPIC detectors are well fitted by a power law with extra-absorption at z=0.524; the energy index in the 0.2-10 keV range is well constrained: ?=0.645 ± 0.028 and the 1 keV flux density is 0.311 ± 0.008~? Jy. The analysis of the X-ray light curves reveals that no significant variations occurred during the pointing. In contrast, simultaneous dense radio monitoring with the 100 m telescope at Effelsberg shows a ~2-3% flux decrease in 6-7 h, which, if intrinsic, would imply a brightness temperature well above the Compton limit and hence a lower limit to the Doppler factor ? ? 46. We construct the broad-band spectral energy distribution of January 18-19, 2004 with simultaneous radio data from Effelsberg, optical data from the Nordic Optical Telescope (NOT), optical-UV data from the Optical Monitor onboard XMM-Newton, and X-ray data by the EPIC instruments. Particular care is taken to correct data for extinction due to both the Milky Way and the z=0.524 absorber. The resulting SED suggests the existence of a bump in the UV spectral region.

  12. Is the lag screw sliding effective in the intramedullary nailing in A1 and A2 AO-OTA intertrochanteric fractures? A prospective study of Sliding and None-sliding lag screw in Gamma-III nail

    PubMed Central

    2012-01-01

    Object To compare the Sliding with Non-sliding lag screw of a gamma nail in the treatment of A1 and A2 AO-OTA intertrochanteric fractures. Materials and methods 80 patients were prospectively collected. In each group, AO/OTA 31-A were classified into group A. AO/OTA 31-A2.1 was classified as group B. We classified the A2.2 and A2.3 as group C. According to the set-screw locking formation of Gamma-III, the cases were randomly allocated to Sliding subgroup and Non-sliding subgroup in A, B and C groups. Follow-ups were performed 1, 3, 6 and 12 months postoperatively. Results In the Sliding group, the bone healing rate 3, 6, 12 months postoperatively reached 85.00%, 97.50%, 100% in group A, B and C. Meanwhile, in Non-sliding group, postoperatively, bone healing rate were 90.00%, 95.00% and 97.50% in group A, B and C, respectively. Both differences were not significant. Lower limb discrepancy between Sliding and Non-sliding pattern was significantly different in group C which represent fracture types of AO/OTA 31-A2.2 and A2.3 (0.573 ± 0.019 mm in Non-sliding group, 0.955 mm ± 0.024 mm in Sliding group, P < 0.001 ). Difference of sliding distance among the three groups was significant among group A, B and C: 0.48 mm ± 0.04 mm, 0.62 mm ± 0.07 mm and 0.92 mm ± 0.04 mm (P < 0.001). Differences in average healing time and Harris scores also presented no significance in the three groups. Conclusions As a result, we can conclude that the sliding distance is minimal in Gamma nails and it is related to the comminuted extent of the intertrochanteric area in A1 and A2 AO-OTA intertrochanteric fractures. For treating these kinds of fractures, the sliding of the lag screw of an Gamma nail does not improve any clinical results and in certain cases, such as highly comminuted A1 and A2 fractures, can therefore even benefit from a locked lag screw by tightening the set-screw. PMID:22938031

  13. Expression of Cry1Ac in transgenic tobacco plants under the control of a wound-inducible promoter (AoPR1) isolated from Asparagus officinalis to control Heliothis virescens and Manduca sexta.

    PubMed

    Gulbitti-Onarici, Selma; Zaidi, Mohsin Abbas; Taga, Ibrahim; Ozcan, Sebahattin; Altosaar, Illimar

    2009-07-01

    Expression of cry1Ac gene from Bacillus thuringiensis (Bt) was evaluated under the control of a wound-inducible AoPR1 promoter from Asparagus officinalis in transgenic tobacco plants. The leaves of transgenic plants were mechanically wounded to evaluate the activity of the AoPR1 promoter in driving the expression of Cry1Ac protein at the wound site. Our results indicate that mechanical wounding of transgenic plants was effective in inducing the expression of Cry1Ac protein. As a result of this induction, the accumulated levels of Cry1Ac protein increased during 6-72 h post-wounding period. The leaves of transgenic tobacco plants were evaluated for resistance against Heliothis virescens and Manduca sexta in insect bioassays in two different ways. The detached tobacco leaves were either fed directly to the insect larvae or they were first mechanically wounded followed by a 72 h post-wounding feeding period. Complete protection of mechanically wounded leaves of transgenic plants was observed within 24 h of the bioassay. The leaves of transgenic plants fed directly (without pre-wounding) to the larvae achieved the same level of protection between 24 and 72 h of the bioassay. PMID:19353306

  14. Compilação de dados atômicos e moleculares do UV ao IV próximo para uso em síntese espectral

    NASA Astrophysics Data System (ADS)

    Coelho, P.; Barbuy, B.; Melendez, J.; Allen, D. M.; Castilho, B.

    2003-08-01

    Espectros sintéticos são utéis em uma grande variedade de aplicações, desde análise de abundâncias em espectros estelares de alta resolução ao estudo de populações estelares em espectros integrados. A confiabilidade de um espectro sintético depende do modelo de atmosfera adotado, do código de formação de linhas e da qualidade dos dados atômicos e moleculares que são determinantes no cálculo das opacidades da fotosfera. O nosso grupo no departamento de Astronomia no IAG tem utilizado espectros sintéticos há mais de 15 anos, em aplicações voltadas principalmente para a análise de abundâncias de estrelas G, K e M e populações estelares velhas. Ao longo desse tempo, as listas de linhas vieram sendo construídas e atualizadas continuamente, e alguns acréscimos recentes podem ser citados: Castilho (1999, átomos e moléculas no UV), Schiavon (1998, bandas moleculares de TiO) e Melendez (2001, átomos e moléculas no IV próximo). Com o intuito de calcular uma grade de espectros do UV ao IV próximo para uso no estudo de populações estelares velhas, se fazia necessário compilar e homogeneizar as diversas listas em apenas uma lista atômica e uma molecular. Nesse processo, a nova lista compilada foi correlacionada com outras bases de dados (NIST, Kurucz Database, O' Brian et al. 1991) para atualização dos parâmetros que caracterizam a transição atômica (comprimento de onda, log gf e potencial de excitação). Adicionalmente as constantes de interação C6 foram calculadas segundo a teoria de Anstee & O'Mara (1995) e artigos posteriores. As bandas moleculares de CH e CN foram recalculadas com o programa LIFBASE (Luque & Crosley 1999). Nesse poster estão detalhados os procedimentos citados acima, as comparações entre espectros calculados com as novas listas e espectros observados em alta resolução do Sol e de Arcturus, e uma análise do impacto decorrente da utilização de diferentes modelos de atmosfera no espectro sintético. Ao final, temos uma lista de linhas atômicas com mais de 24.000 linhas e uma lista molecular com as moléculas CN, CH, OH, NH, MgH, C2, TiO Gama, CO, FeH, adequadas ao estudo de estrelas G, K e M e populações estelares velhas.

  15. Sr2Mn3Sb2O2 type oxyselenides: structures, magnetism, and electronic properties of Sr2AO2M2Se2 (A=Co, Mn; M=Cu, Ag).

    PubMed

    Jin, Shifeng; Chen, Xiaolong; Guo, Jiangang; Lei, Ming; Lin, Jingjing; Xi, Jianguo; Wang, Wenjun; Wang, Wanyan

    2012-10-01

    Four new oxyselenides with nominal formula Sr(2)AO(2)M(2)Se(2) (A=Co, Mn; M=Cu, Ag) have been synthesized. They all crystallize in an I4/mmm space group and consist of alternating perovskite-like (Sr(2)AO(2))(2+) blocks and antiflourie (M(2)Se(2))(2-) layers, which are relatively rare layered oxyselenides reported so far that are isostructural to Sr(2)Mn(3)Sb(2)O(2). From powder X-ray diffraction data, compounds Sr(2)CoO(2)Cu(2)Se(2) and Sr(2)CoO(2)Ag(2)Se(2) are found near stoichiometric, whereas Sr(2)MnO(2)Cu(2-?)Se(2) and Sr(2)MnO(2)Ag(2-?)Se(2) possess substantial copper or silver vacancies (??0.5), consistent with their oxysulfide analogues. X-ray photoelectron spectroscopy measurements indicate the readily oxidization of Mn(2+) ions should be responsible for the occurrence of Cu/Ag vacancies. The rigid (Sr(2)AO(2))(2+) blocks within these compounds constrain the basal lattice parameters in the ab plane and result in largely deformed tetrahedral sites for the large silver ions. Magnetic susceptibility measurements of Sr(2)CoO(2)M(2)Se(2) (M=Cu, Ag) show complex antiferromagnetic transitions, while Sr(2)MnO(2)M(2-?)Se(2) (M=Cu, Ag) show high-temperature Curie-Weiss behavior, followed by low-temperature antiferromagnetic transitions at 54 K and 67 K, respectively. Except for Sr(2)MnO(2)Ag(2-?)Se(2), the other three compounds exhibit p-type semiconducting transport properties, with the measured resistivities several orders lower than their oxysulfide analogues. Hall measurement reveals high mobilities of Sr(2)CoO(2)M(2)Se(2) (M=Cu, Ag) compounds at room temperature. The unusually small optical band gaps (~0.07 eV) of Sr(2)CoO(2)Cu(2)Se(2), Sr(2)CoO(2)Ag(2)Se(2), and Sr(2)MnO(2)Cu(2-?)Se(2) are also reported. PMID:22967274

  16. A Modified Mixing Length Turbulence Model for Zero and Adverse Pressure Gradients. M.S. Thesis - Akron Univ., 1993

    NASA Technical Reports Server (NTRS)

    Conley, Julianne M.; Leonard, B. P.

    1994-01-01

    The modified mixing length (MML) turbulence model was installed in the Proteus Navier-Stokes code, then modified to make it applicable to a wider range of flows typical of aerospace propulsion applications. The modifications are based on experimental data for three flat-plate flows having zero, mild adverse, and strong adverse pressure gradients. Three transonic diffuser test cases were run with the new version of the model in order to evaluate its performance. All results are compared with experimental data and show improvements over calculations made using the Baldwin-Lomax turbulence model, the standard algebraic model in Proteus.

  17. Vibration-translation energy transfer in vibrationally excited diatomic molecules. Ph.D. Thesis - York Univ., Toronto

    NASA Technical Reports Server (NTRS)

    Mckenzie, R. L.

    1976-01-01

    A semiclassical collision model is applied to the study of energy transfer rates between a vibrationally excited diatomic molecule and a structureless atom. The molecule is modeled as an anharmonic oscillator with a multitude of dynamically coupled vibrational states. Three main aspects in the prediction of vibrational energy transfer rates are considered. The applicability of the semiclassical model to an anharmonic oscillator is first evaluated for collinear encounters. Second, the collinear semiclassical model is applied to obtain numerical predictions of the vibrational energy transfer rate dependence on the initial vibrational state quantum number. Thermally averaged vibration-translation rate coefficients are predicted and compared with CO-He experimental values for both ground and excited initial states. The numerical model is also used as a basis for evaluating several less complete but analytic models. Third, the role of rational motion in the dynamics of vibrational energy transfer is examined. A three-dimensional semiclassical collision model is constructed with coupled rotational motion included. Energy transfer within the molecule is shown to be dominated by vibration-rotation transitions with small changes in angular momentum. The rates of vibrational energy transfer in molecules with rational frequencies that are very small in comparison to their vibrational frequency are shown to be adequately treated by the preceding collinear models.

  18. An Exponential Finite Difference Technique for Solving Partial Differential Equations. M.S. Thesis - Toledo Univ., Ohio

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.

    1987-01-01

    An exponential finite difference algorithm, as first presented by Bhattacharya for one-dimensianal steady-state, heat conduction in Cartesian coordinates, has been extended. The finite difference algorithm developed was used to solve the diffusion equation in one-dimensional cylindrical coordinates and applied to two- and three-dimensional problems in Cartesian coordinates. The method was also used to solve nonlinear partial differential equations in one (Burger's equation) and two (Boundary Layer equations) dimensional Cartesian coordinates. Predicted results were compared to exact solutions where available, or to results obtained by other numerical methods. It was found that the exponential finite difference method produced results that were more accurate than those obtained by other numerical methods, especially during the initial transient portion of the solution. Other applications made using the exponential finite difference technique included unsteady one-dimensional heat transfer with temperature varying thermal conductivity and the development of the temperature field in a laminar Couette flow.

  19. Symposium on Electromagnetic Launch Technology, 6th, Univ. of Texas, Austin, Apr. 28-30, 1992, Proceedings

    NASA Astrophysics Data System (ADS)

    Grosser, Julie K.

    1993-01-01

    The present conference discusses topics in the military and commercial applications of electrical launcher systems, electromagnetic and electrothermal 'railgun' launchers, 'coilguns', armature and launcher designs, power-conditioning and energy storage systems, and launcher materials and structures and their diagnostics. Attention is given to an earth-to-orbit railgun launcher, polyphase and multiphase railguns, hypervelocity projectile design, determining the Lorentz forces in plasma armatures, pulse power generators, advanced compulsator technology, airborne-platform electric launcher applications, magnetic design for structural stiffness, current multipliers, pulse-forming network design, and cannon-caliber electromagnetic launchers.

  20. Transient response to three-phase faults on a wind turbine generator. Ph.D. Thesis - Toledo Univ.

    NASA Technical Reports Server (NTRS)

    Gilbert, L. J.

    1978-01-01

    In order to obtain a measure of its responses to short circuits a large horizontal axis wind turbine generator was modeled and its performance was simulated on a digital computer. Simulation of short circuit faults on the synchronous alternator of a wind turbine generator, without resort to the classical assumptions generally made for that analysis, indicates that maximum clearing times for the system tied to an infinite bus are longer than the typical clearing times for equivalent capacity conventional machines. Also, maximum clearing times are independent of tower shadow and wind shear. Variation of circuit conditions produce the modifications in the transient response predicted by analysis.

  1. Interactive calculation procedure for supersonic flows. Ph.D. Thesis - Case Western Reserve Univ., 1976. Final Report

    NASA Technical Reports Server (NTRS)

    Tassa, Y.; Anderson, B. H.; Reshotko, E.

    1977-01-01

    An interactive procedure was developed for supersonic viscous flows that can be used for either two-dimensional or axisymmetric configurations. The procedure is directed to supersonic internal flows as well as those supersonic external flows that require consideration of mutual interaction between the outer flow and the boundary layer flow. The flow field is divided into two regions: an inner region which is highly viscous and mostly subsonic and an outer region where the flow is supersonic and in which viscous effects are small but not negligible. For the outer region a numerical solution is obtained by applying the method of characteristics to a system of equations which includes viscous and conduction transport terms only normal to the streamlines. The inner region is treated by a system of equations of the boundary layer type that includes higher order effects such as longitudinal and transverse curvature and normal pressure gradients. These equations are coupled and solved simultaneously in the physical coordinates by using an implicit finite difference scheme. This system can also be used to calculate laminar and turbulent boundary layers using a scalar eddy viscosity concept.

  2. Theoretical studies in medium-energy nuclear and hadronic physics. [Indiana Univ. Nuclear Theory Center and Department of Physics

    SciTech Connect

    Horowitz, C J; Macfarlane, M H; Matsui, T; Serot, B D

    1993-01-01

    A proposal for theoretical nuclear physics research is made for the period April 1, 1993 through March 31, 1996. Research is proposed in the following areas: relativistic many-body theory of nuclei and nuclear matter, quasifree electroweak scattering and strange quarks in nuclei, dynamical effects in (e,e[prime]p) scattering at large momentum transfer, investigating the nucleon's parton sea with polarized leptoproduction, physics of ultrarelativistic nucleus[endash]nucleus collisions, QCD sum rules and hadronic properties, non-relativistic models of nuclear reactions, and spin and color correlations in a quark-exchange model of nuclear matter. Highlights of recent research, vitae of principal investigators, and lists of publications and invited talks are also given. Recent research dealt primarily with medium-energy nuclear physics, relativistic theories of nuclei and the nuclear response, the nuclear equation of state under extreme conditions, the dynamics of the quark[endash]gluon plasma in relativistic heavy-ion collisions, and theories of the nucleon[endash]nucleon force.

  3. Theoretical nuclear reaction and structure studies using hyperons and photons. [Dept. of Physics, North Carolina State Univ. , Raleigh, North Carolina

    SciTech Connect

    Cotanch, S.R.

    1992-01-01

    Research in three principal areas is summarized: (1) Work in elementary hadron structure seeks to further the understanding of hadron structure within the framework of quantum chromodynamics (QCD) and QCD-based models. A comparative study of meson properties employed three relativistic models: an extended Dziembowski model, a generalized light-front approach, and a completely covariant null plane approach. (2) Work on the electromagnetic production of strangeness addressed systems involving the strange quark (hyperons) and hyperon electromagnetic production and radiative capture processes. (3) In the work on medium-energy photonuclear reactions, a large-scale continuum shell-model calculation was performed for ([gamma],N) and (N,[gamma]) reactions at low and medium energies spanning the [Delta] isobar region.

  4. Optical computing and neural networks; Proceedings of the Meeting, National Chiao Tung Univ., Hsinchu, Taiwan, Dec. 16, 17, 1992

    NASA Technical Reports Server (NTRS)

    Hsu, Ken-Yuh (editor); Liu, Hua-Kuang (editor)

    1992-01-01

    The present conference discusses optical neural networks, photorefractive nonlinear optics, optical pattern recognition, digital and analog processors, and holography and its applications. Attention is given to bifurcating optical information processing, neural structures in digital halftoning, an exemplar-based optical neural net classifier for color pattern recognition, volume storage in photorefractive disks, and microlaser-based compact optical neuroprocessors. Also treated are the optical implementation of a feature-enhanced optical interpattern-associative neural network model and its optical implementation, an optical pattern binary dual-rail logic gate module, a theoretical analysis for holographic associative memories, joint transform correlators, image addition and subtraction via the Talbot effect, and optical wavelet-matched filters. (No individual items are abstracted in this volume)

  5. Finite Element Analysis of Active and Sensory Thermopiezoelectric Composite Materials. Degree awarded by Northwestern Univ., Dec. 2000

    NASA Technical Reports Server (NTRS)

    Lee, Ho-Jun

    2001-01-01

    Analytical formulations are developed to account for the coupled mechanical, electrical, and thermal response of piezoelectric composite materials. The coupled response is captured at the material level through the thermopiezoelectric constitutive equations and leads to the inherent capability to model both the sensory and active responses of piezoelectric materials. A layerwise laminate theory is incorporated to provide more accurate analysis of the displacements, strains, stresses, electric fields, and thermal fields through-the-thickness. Thermal effects which arise from coefficient of thermal expansion mismatch, pyroelectric effects, and temperature dependent material properties are explicitly accounted for in the formulation. Corresponding finite element formulations are developed for piezoelectric beam, plate, and shell elements to provide a more generalized capability for the analysis of arbitrary piezoelectric composite structures. The accuracy of the current formulation is verified with comparisons from published experimental data and other analytical models. Additional numerical studies are also conducted to demonstrate additional capabilities of the formulation to represent the sensory and active behaviors. A future plan of experimental studies is provided to characterize the high temperature dynamic response of piezoelectric composite materials.

  6. The feasibility of a high-altitude aircraft platform with consideration of technological and societal constraints. Thesis - Kansas Univ.

    NASA Technical Reports Server (NTRS)

    Graves, E. B.

    1982-01-01

    The feasibility of remotely piloted aircraft performing year around missions at an altitude of 70,000 feet is determined. Blimp and airplane type vehicles employing solar-voltaic, microwave, or nuclear propulsion systems were considered. A payload weighing 100 pounds and requiring 1000 watts of continuous power was assumed for analysis purposes. Results indicate that a solar powered aircraft requires more solar cell area than is available on conventional aircraft configurations if designed for the short days and high wind speeds associated with the winter season. A conventionally shaped blimp that uses solar power appears feasible if maximum airspeed is limited to about 100 ft/s. No viable airplane configuration that uses solar power and designed to withstand the winter environment was found. Both a conventionally shaped blimp and airplane appear feasible using microwave power. Nuclear powered aircraft of these type are also feasible. Societal attitudes toward the use of solar power in high altitude aircraft appear favorable. The use of microwave power for this purpose is controversial, even though the ground station required would transmit power at levels comparable to existing satellite communications stations.

  7. A comparison of simulated and experimental wave spectra in the nearshore region. M.S. Thesis - Old Dominion Univ.

    NASA Technical Reports Server (NTRS)

    Morris, W. D.

    1979-01-01

    The results of comparing the experimental spectra measured over the shelf with spectra measured in deepwater conditions indicated that statistically significant changes occurred over the shelf region that could be attributed to shoaling and refraction effects. The comparison of the simulated spectra with the experimental agreed well at the 80% confidence level for all but the most inshore data segment. The total energy also showed similar agreement. However, the theoretical frequency at which peak spectral density occurred did not follow the decreasing trend seen in the experimental data. Guidelines are proposed for determining the type wavefield to which the modeling technique can best be applied, and caution is given on the selection of the digitization rate necessary to ensure sufficient detail for analysis of wave data.

  8. Modification of the MML turbulence model for adverse pressure gradient flows. M.S. Thesis - Akron Univ., 1993

    NASA Technical Reports Server (NTRS)

    Conley, Julianne M.

    1994-01-01

    Computational fluid dynamics is being used increasingly to predict flows for aerospace propulsion applications, yet there is still a need for an easy to use, computationally inexpensive turbulence model capable of accurately predicting a wide range of turbulent flows. The Baldwin-Lomax model is the most widely used algebraic model, even though it has known difficulties calculating flows with strong adverse pressure gradients and large regions of separation. The modified mixing length model (MML) was developed specifically to handle the separation which occurs on airfoils and has given significantly better results than the Baldwin-Lomax model. The success of these calculations warrants further evaluation and development of MML. The objective of this work was to evaluate the performance of MML for zero and adverse pressure gradient flows, and modify it as needed. The Proteus Navier-Stokes code was used for this study and all results were compared with experimental data and with calculations made using the Baldwin-Lomax algebraic model, which is currently available in Proteus. The MML model was first evaluated for zero pressure gradient flow over a flat plate, then modified to produce the proper boundary layer growth. Additional modifications, based on experimental data for three adverse pressure gradient flows, were also implemented. The adapted model, called MMLPG (modified mixing length model for pressure gradient flows), was then evaluated for a typical propulsion flow problem, flow through a transonic diffuser. Three cases were examined: flow with no shock, a weak shock and a strong shock. The results of these calculations indicate that the objectives of this study have been met. Overall, MMLPG is capable of accurately predicting the adverse pressure gradient flows examined in this study, giving generally better agreement with experimental data than the Baldwin-Lomax model.

  9. Mathematical crew motion disturbance models for spacecraft control system design. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Conway, B. A.

    1974-01-01

    Several techniques for modeling the disturbances to a spacecraft's attitude caused by moving crew members are presented. These disturbances can be the largest moments acting on a manned spacecraft, and knowledge of their effect is important in the sizing, design, and analysis/simulation of spacecraft attitude control systems. The modeling techniques are identified as two principal types: deterministic and stochastic. Three techniques of each type are presented. The deterministic models include point-mass motion derivatives and a discussion on dynamic models of moving crew members. The stochastic techniques are highlighted by a Fourier transform method and the representation of long-term crew disturbance activities as outputs from appropriately designed filters. A z-transform technique is developed to obtain a difference-equation form of stochastic models for use on digital computers. An appendix derives spacecraft equations of motion which can be used with many of the models discussed.

  10. Design of the Wind Tunnel Model Communication Controller Board. Degree awarded by Christopher Newport Univ. on Dec. 1998

    NASA Technical Reports Server (NTRS)

    Wilson, William C.

    1999-01-01

    The NASA Langley Research Center's Wind Tunnel Reinvestment project plans to shrink the existing data acquisition electronics to fit inside a wind tunnel model. Space limitations within a model necessitate a distributed system of Application Specific Integrated Circuits (ASICs) rather than a centralized system based on PC boards. This thesis will focus on the design of the prototype of the communication Controller board. A portion of the communication Controller board is to be used as the basis of an ASIC design. The communication Controller board will communicate between the internal model modules and the external data acquisition computer. This board is based around an Field Programmable Gate Array (FPGA), to allow for reconfigurability. In addition to the FPGA, this board contains buffer Random Access Memory (RAM), configuration memory (EEPROM), drivers for the communications ports, and passive components.

  11. Evaluation of equilibrium turbulence for a hypersonic boundary layer at nonadiabatic wall conditions. M.S. Thesis - Old Dominion Univ.

    NASA Technical Reports Server (NTRS)

    Albertson, Cindy W.

    1989-01-01

    This paper presents an experimental study to characterize the naturally developing compressible turbulent boundary layer produced along a flat plate measuring 9.7 feet long in the NASA Langley 8-Foot High Temperature Tunnel and to determine the test conditions necessary to achieve equilibrium turbulence. The measurements consist of pitot pressure, static pressure, and total temperature distributions in the boundary layer. In addition, surface measurements consisting of heat transfer and pressure distributions were obtained. The tests were conducted at a nominal free-stream Mach number of 6.5, total temperatures of 2700 and 3300 R, and angles of attack of 5 and 13 degrees. The corresponding nominal boundary-layer edge Mach numbers were 6.2 and 5.0. The nominal ratios of adiabatic wall temperature to cold wall temperature were 4.4 and 5.4 and the momentum thickness Reynolds numbers at the boundary layer probe locations ranged from 400 to 7800. The results of this study indicate that momentum thickness Reynolds numbers of at least 4000 are required to obtain an equilibrium turbulent boundary layer in the Langley 8-Foot High Temperature Tunnel. This evaluation is based primarily on the behavior of shape factors inferred from the boundary-layer measurements.

  12. Experimental studies of pion-nucleus interactions at intermediate energies. [New Mexico State Univ. , Las Cruces, New Mexico

    SciTech Connect

    Not Available

    1992-12-31

    This report summarizes investigations of various pion-nucleus interactions and nucleon-nucleus charge-exchange reactions. The work was carried out with the LAMPF accelerator at the Los Alamos National Laboratory and the cyclotrons at the Paul Scherrer Institute (PSI) near Zurich, Switzerland, and at Indiana University (IUCF), as a collaborative effort among several laboratories and universities. The experimental activity at LAMPF involved measurements of new data on pion double-charge-exchange scattering, some initial work on a new Neutral Meson Spectrometer system, a search for deeply-bound pionic atoms, measurements of elastic scattering, and studies of the (n,p) reaction on various nuclei. At PSI measurements of pion quasielastic scattering were carried out, with detection of the recoil proton. Work on the analysis of data from a previous experiment at PSI on pion absorption in nuclei was continued. This experiment involved using a detector system that covered nearly the full solid angle.

  13. Galactic background maps at 3.93 and 6.55 MHz. M.S. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Novaco, J. C.

    1973-01-01

    The Radio Astronomy Explorer Satellite (RAE-1), its hardware and its data processing are discussed. The data from the prime mapping antenna are discussed with emphasis on the problems involved in reducing the data. Particular attention is drawn to two problems - receiver instability and ground breakthrough - and their influence on the data. Galactic background maps of the nonthermal radiation at 3.93 and 6.55 MHz are produced. It is demonstrated that the positional uncertainity of the maps is about 20 deg. The maps at 3.93 and 6.55 MHz are compared to two ground based maps made at higher frequencies that are smoothed to the larger RAE antenna patterns.

  14. Contributions on the Subject of Longitudinal Movements of Aircraft in Wind Shears. Ph.D. Thesis - Technischen Univ., 1983

    NASA Technical Reports Server (NTRS)

    Krauspe, P.

    1985-01-01

    The effect of downburst-type wind shears on the longitudinal dynamic behavior of an unguided aircraft is simulated numerically on the basis of published meteorological data and the flight characteristics of an A300-B passenger jet. The nonlinear differential equations of the aircraft motion are linearized by conventional methods, and the wind effects are introduced via the linear derivatives of the wind components referred to the wind gradients to obtain simplified technical models of the longitudinal response to all possible types of constant-gradient wind shears during the first 20-60 sec. Graphs, maps, and diagrams are provided, and a number of accidents presumed to have involved wind shears are analyzed in detail.

  15. Numerical Study of Rarefied Hypersonic Flow Interacting with a Continuum Jet. Degree awarded by Pennsylvania State Univ., Aug. 1999

    NASA Technical Reports Server (NTRS)

    Glass, Christopher E.

    2000-01-01

    An uncoupled Computational Fluid Dynamics-Direct Simulation Monte Carlo (CFD-DSMC) technique is developed and applied to provide solutions for continuum jets interacting with rarefied external flows. The technique is based on a correlation of the appropriate Bird breakdown parameter for a transitional-rarefied condition that defines a surface within which the continuum solution is unaffected by the external flow-jet interaction. The method is applied to two problems to assess and demonstrate its validity; one of a jet interaction in the transitional-rarefied flow regime and the other in the moderately rarefied regime. Results show that the appropriate Bird breakdown surface for uncoupling the continuum and non-continuum solutions is a function of a non-dimensional parameter relating the momentum flux and collisionality between the two interacting flows. The correlation is exploited for the simulation of a jet interaction modeled for an experimental condition in the transitional-rarefied flow regime and the validity of the correlation is demonstrated. The uncoupled technique is also applied to an aerobraking flight condition for the Mars Global Surveyor spacecraft with attitude control system jet interaction. Aerodynamic yawing moment coefficients for cases without and with jet interaction at various angles-of-attack were predicted, and results from the present method compare well with values published previously. The flow field and surface properties are analyzed in some detail to describe the mechanism by which the jet interaction affects the aerodynamics.

  16. A Management Information System Model for Program Management. Ph.D. Thesis - Oklahoma State Univ.; [Computerized Systems Analysis

    NASA Technical Reports Server (NTRS)

    Shipman, D. L.

    1972-01-01

    The development of a model to simulate the information system of a program management type of organization is reported. The model statistically determines the following parameters: type of messages, destinations, delivery durations, type processing, processing durations, communication channels, outgoing messages, and priorites. The total management information system of the program management organization is considered, including formal and informal information flows and both facilities and equipment. The model is written in General Purpose System Simulation 2 computer programming language for use on the Univac 1108, Executive 8 computer. The model is simulated on a daily basis and collects queue and resource utilization statistics for each decision point. The statistics are then used by management to evaluate proposed resource allocations, to evaluate proposed changes to the system, and to identify potential problem areas. The model employs both empirical and theoretical distributions which are adjusted to simulate the information flow being studied.

  17. A spatial model of wind shear and turbulence for flight simulation. Ph.D. Thesis - Colorado State Univ.

    NASA Technical Reports Server (NTRS)

    Campbell, C. W.

    1984-01-01

    A three dimensional model which combines measurements of wind shear in the real atmosphere with three dimensional Monte Carlo simulated turbulence was developed. The wind field over the body of an aircraft can be simulated and all aerodynamic loads and moments calculated.

  18. Medium Energy measurements on N-N parameters. [Dept. of Physics, Univ. of Texas at Austin, Austin, Texas

    SciTech Connect

    Ambrose, D.; Bachman, M.; Coffey, P.; Glass, G.; Jobst, B.; McNaughton, K.H.; Nguyen, C.; Riley, P.J.

    1992-12-01

    Research is reported on the following topics: Spin transfer measurements in np elastic scattering; pp elastic differential cross section measurements; single pion production in np scattering; and a new search for rare kaon decays (K[sub L][yields][mu][mu] and K[sub L][yields]ee). 68 refs., 33 figs, 3 tabs.

  19. Structure de l'univers - quand l'observation guide la théorie... ou pas

    NASA Astrophysics Data System (ADS)

    Nazé, Yaël

    The scientific method is often presented, e.g. to children, as a linear process, starting by a question and ending by the elaboration of a theory, with a few experiments in-between. The reality of the building of science is much more complex, with back-and-forth motions between theories and observations, with some intervention of technology and randomness. This complex process is not always correctly understood and assimilated, even amongst scientists. The hero cult, mixed with some revisionism, still exists despite in-depth historical studies. In this context, it may be useful to comparatively examine the reaction to crucial observations, their interpretation and their impact on the contemporaneous theory development. Four examples are presented here, all linked to the question of the 'construction of the heavens' but at different epochs.

  20. Computational aspects of sensitivity calculations in linear transient structural analysis. Ph.D. Thesis - Virginia Polytechnic Inst. and State Univ.

    NASA Technical Reports Server (NTRS)

    Greene, William H.

    1990-01-01

    A study was performed focusing on the calculation of sensitivities of displacements, velocities, accelerations, and stresses in linear, structural, transient response problems. One significant goal of the study was to develop and evaluate sensitivity calculation techniques suitable for large-order finite element analyses. Accordingly, approximation vectors such as vibration mode shapes are used to reduce the dimensionality of the finite element model. Much of the research focused on the accuracy of both response quantities and sensitivities as a function of number of vectors used. Two types of sensitivity calculation techniques were developed and evaluated. The first type of technique is an overall finite difference method where the analysis is repeated for perturbed designs. The second type of technique is termed semi-analytical because it involves direct, analytical differentiation of the equations of motion with finite difference approximation of the coefficient matrices. To be computationally practical in large-order problems, the overall finite difference methods must use the approximation vectors from the original design in the analyses of the perturbed models. In several cases this fixed mode approach resulted in very poor approximations of the stress sensitivities. Almost all of the original modes were required for an accurate sensitivity and for small numbers of modes, the accuracy was extremely poor. To overcome this poor accuracy, two semi-analytical techniques were developed. The first technique accounts for the change in eigenvectors through approximate eigenvector derivatives. The second technique applies the mode acceleration method of transient analysis to the sensitivity calculations. Both result in accurate values of the stress sensitivities with a small number of modes and much lower computational costs than if the vibration modes were recalculated and then used in an overall finite difference method.