National Library of Energy BETA

Sample records for mas mas mas

  1. MAS275 Probability Modelling 2 Renewal Theory

    E-Print Network [OSTI]

    Jordan, Jonathan

    MAS275 Probability Modelling 2 Renewal Theory 2.1 Renewal processes in discrete time Renewal will model the lengths of time between renewals (e.g. the life-lengths of light bulbs) as random variables there is an occurrence called a renewal, and at the points of time between these renewals, nothing happens. For example

  2. Protein MAS NMR methodology and structural analysis of protein assemblies

    E-Print Network [OSTI]

    Bayro, Marvin J

    2010-01-01

    Methodological developments and applications of solid-state magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy, with particular emphasis on the analysis of protein structure, are described in this thesis. ...

  3. Broadband solid-state MAS NMR of paramagnetic systems

    E-Print Network [OSTI]

    Pell, Andrew J.; Pintacuda, Guido

    2014-12-26

    that Hartmann–Hahn matching condition [28]. How- ever CP is generally inefficient when applied to paramagnetic systems because the long contact pulses are not sufficiently broadband to spin lock effectively over the whole spectral bandwidth. For MAS frequencies...

  4. NanoMas Technologies Inc | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History ViewMayo, Maryland:NPI Ventures Ltd Jump to: navigation, search59Naknek,C Jump to:NanoEnerNanoMas

  5. Higher Order Amyloid Fibril Structure by MAS NMR and DNP Spectroscopy

    E-Print Network [OSTI]

    Debelouchina, Galia T.

    Protein magic angle spinning (MAS) NMR spectroscopy has generated structural models of several amyloid fibril systems, thus providing valuable information regarding the forces and interactions that confer the extraordinary ...

  6. Development of a generic, computerized nuclear material accountability system: NucMAS

    SciTech Connect (OSTI)

    Cornell, M.D.; O'Leary, J.M.

    1987-01-01

    The application NucMAS provides basic computerized accountability functions for the Savannah River Plant (SRP) Separations Department Material Balance Areas (MBA's). These functions include data entry, data management, calculations, and report generation. NucMAS can be used both for routine reporting to the SRP central Material Control and Accounting (MC and A) system and for rapid ad hoc queries in emergency situations. The system is designed to work with any process handling one or more of the 17 accountable nuclear materials specified by the Department of Energy (DOE). It relies on user-supplied configuration data to drive data prompts, report headings, data validations, and calculations.

  7. The Role of MAS as a Decision Support Tool in a Water-Rights Market

    E-Print Network [OSTI]

    Garrido, Antonio

    The Role of MAS as a Decision Support Tool in a Water-Rights Market Vicente Botti1 , Antonio@iiia.csic.es Abstract. Water is getting a more and more scarce resource, which motivates the idea of designing a framework where water rights may be exchanged more freely, thus leading to a more efficient use of water

  8. Managing water demand as a regulated open MAS. (Work in progress)

    E-Print Network [OSTI]

    Garrido, Antonio

    1 Managing water demand as a regulated open MAS. (Work in progress) Vicente Botti 1 , Antonio Scientific Research Council, {vbotti,agarridot,agiret}@dsic.upv.es, pablo@iiia.csic.es I. WATER MANAGEMENT of water policy is the need to foster a more rational use of the resource and this may be addressed

  9. Managing water demand as a regulated open MAS. (Work in progress)

    E-Print Network [OSTI]

    Garrido, Antonio

    1 Managing water demand as a regulated open MAS. (Work in progress) Vicente Botti1 , Antonio Scientific Research Council, {vbotti,agarridot,agiret}@dsic.upv.es, pablo@iiia.csic.es I. WATER MANAGEMENT of water policy is the need to foster a more rational use of the resource and this may be addressed

  10. MANAGEMENT OF DANGEROUS GOODS IN CONTAINER TERMINAL WITH MAS Mansoriya Hamidou*

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    MANAGEMENT OF DANGEROUS GOODS IN CONTAINER TERMINAL WITH MAS MODEL Mansoriya Hamidou* , Dominique the dangerous container storage problem. It is an optimization problem since the aim is to improve the container. Keywords: container terminal, dangerous container, multi-agents system, security 1. INTRODUCTION This paper

  11. Seminario Informal (mas Formal!) 2006 Estrategias da Teoria de Reescrita em PVS

    E-Print Network [OSTI]

    Ayala-Rincón, Mauricio

    4o Semin´ario Informal (mas Formal!) 2006 Estrat´egias da Teoria de Reescrita em PVS: considerac Reescrita Porque Estrat´egias em PVS s~ao Importantes Conclus~ao e Trabalho Futuro Andr´e Luiz Galdino

  12. Programming MAS without Programming Agents Munindar P. Singh and Amit K. Chopra

    E-Print Network [OSTI]

    Programming MAS without Programming Agents Munindar P. Singh and Amit K. Chopra North Carolina State University, Universit`a degli Studi di Trento May 2009 singh@ncsu.edu, akchopra The environment in which it will be instantiated as a system singh@ncsu.edu, akchopra.mail@gmail.com (NCSU

  13. Decomposition of adsorbed VX on activated carbons studied by {sup 31}P MAS NMR

    SciTech Connect (OSTI)

    Ishay Columbus; Daniel Waysbort; Liora Shmueli; Ido Nir; Doron Kaplan [Israel Institute for Biological Research, Ness Ziona (Israel). Departments of Organic Chemistry and Physical Chemistry

    2006-06-15

    The fate of the persistent OP nerve agent O-ethyl S-(2-(diisopropylamino)ethyl) methylphosphonothioate (VX) on granular activated carbons that are used for gas filtration was studied by means of 31P magic angle spinning (MAS) NMR spectroscopy. Four types of activated carbon were used, including coal-based BPL. VX as vapor or liquid was adsorbed on carbon granules, and MAS NMR spectra were recorded periodically. The results show that at least 90% of the adsorbed VX decomposes within 20 days or less to the nontoxic ethyl methylphosphonic acid (EMPA) and bis(S-2-diisopropylaminoethane) ((DES){sub 2}). Decomposition occurred irrespective of the phase from which VX was loaded, the presence of metal impregnation on the carbon surface, and the water content of the carbon. Theoretical and practical aspects of the degradation are discussed. 17 refs., 6 figs., 3 tabs.

  14. MMAE Co-terminal Degrees Summary Co-terminal Degrees within MMAE (MAS = master of engineering, i.e. non-thesis

    E-Print Network [OSTI]

    Heller, Barbara

    their knowledge in their major area of study (mechanical or aerospace engineering = master of engineering, i.e. non-thesis masters): · BS Mechanical Engineering + MAS Mechanical and Aerospace Engineering · BS Aerospace Engineering + MAS

  15. Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100kHz MAS

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Nishiyama, Y.; Kobayashi, T.; Malon, M.; Singappuli-Arachchige, D.; Slowing, I. I.; Pruski, M.

    2015-02-16

    Two-dimensional 1H{13C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in 1H dimension withoutmore »resorting to 1H–1H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. As a result, the HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.« less

  16. Observations of radio-quiet quasars at 10mas resolution by use of gravitational lensing

    E-Print Network [OSTI]

    Jackson, Neal; Roberts, Carl; Sluse, Dominique; Stacey, Hannah; Vives-Arias, Hector; Wucknitz, Olaf; Volino, Filomena

    2015-01-01

    We present VLA detections of radio emission in four four-image gravitational lens systems with quasar sources: HS0810+2554, RXJ0911+0511, HE0435$-$1223 and SDSSJ0924+0219, and e-MERLIN observations of two of the systems. The first three are detected at a high level of significance, and SDSS J0924+0219 is detected. HS0810+2554 is resolved, allowing us for the first time to achieve 10-mas resolution of the source frame in the structure of a radio quiet quasar. The others are unresolved or marginally resolved. All four objects are among the faintest radio sources yet detected, with intrinsic flux densities in the range 1-5$\\mu$Jy; such radio objects, if unlensed, will only be observable routinely with the Square Kilometre Array. The observations of HS0810+2554, which is also detected with e-MERLIN, strongly suggest the presence of a mini-AGN, with a radio core and milliarcsecond scale jet. The flux densities of the lensed images in all but HE0435-1223 are consistent with smooth galaxy lens models without the req...

  17. The Role of Castes in Formal Specification of MAS School of Computing and Mathematical Sciences, Oxford Brookes University

    E-Print Network [OSTI]

    Zhu, Hong

    The Role of Castes in Formal Specification of MAS Hong Zhu School of Computing and Mathematical of classes, castes introduced in the formal specification language SLAB provide a language facility that provides modularity in the formal specification of multiagent systems. A caste represents a set of agents

  18. A comparison of cloud top heights computed from airborne lidar and MAS radiance data using CO2 slicing

    E-Print Network [OSTI]

    Baum, Bryan A.

    A comparison of cloud top heights computed from airborne lidar and MAS radiance data using CO2]. Other studies have compared CO2- slicing cloud heights with those computed from lidar data [Smith in assessing the accuracy of the CO2-slicing cloud height algorithm. Infrared measurements of upwelling

  19. Abstract. Hart and Mas-Colell [2000] show that if all players play ``regret-matching'' strategies, i.e., they play with probabilities proportional to the

    E-Print Network [OSTI]

    Hart, Sergiu

    Abstract. Hart and Mas-Colell [2000] show that if all players play ``regret- matching'' strategies introduced in Hart and Mas-Colell [2001]. In particular, these simplify the ``conditional smooth fictitious. y The author thanks Professor Sergiu Hart for his help and guidance, and the Associate Editor

  20. 4000 2000 0 -2000 -4000 DE-413 Plu017 + ( 0.0, 0.0) mas DE-413+PLU-017

    E-Print Network [OSTI]

    Young, Leslie A.

    SAAO 4000 2000 0 -2000 -4000 E (km) -4000 -2000 0 2000 4000 N(km) DE-413 Plu017 + ( 0.0, 0.0) mas:51:48 Mean 23:45:58 #12;SAAO 4000 2000 0 -2000 -4000 E (km) -4000 -2000 0 2000 4000 N(km) DE-413 Plu017:39:20 23:44:25 23:36:32 23:49:12 Mean 23:42:52 23:41:25 23:44:19 #12;SAAO 4000 2000 0 -2000 -4000 E (km

  1. CaCl 2 -Accelerated Hydration of Tricalcium Silicate: A STXM Study Combined with 29 Si MAS NMR

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Qinfei; Ge, Yong; Geng, Guoqing; Bae, Sungchul; Monteiro, Paulo J. M.

    2015-01-01

    The effect of calcium chloride (CaCl 2 ) on tricalcium silicate (C 3 S) hydration was investigated by scanning transmission X-ray microscopy (STXM) with Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra and 29 Si MAS NMR. STXM is demonstrated to be a powerful tool for studying the chemical composition of a cement-based hydration system. The Ca L 3,2 -edge NEXAFS spectra obtained by examining C 3 S hydration in the presence of CaCl 2 showed that this accelerator does not change the coordination of calcium in the calcium silicate hydrate (C-S-H), which is the primary hydration product. Omore »K-edge NEXAFS is also very useful in distinguishing the chemical components in hydrated C 3 S. Based on the Ca L 3,2 -edge spectra and chemical component mapping, we concluded that CaCl 2 prefers to coexist with unhydrated C 3 S instead of C-S-H. In Si K-edge NEXAFS analysis, CaCl 2 increases the degree of silicate polymerization of C-S-H in agreement with the 29 Si CP/MAS NMR results, which show that the presence of CaCl 2 in hydrated C 3 S considerably accelerates the formation of middle groups ( Q 2 ) and branch sites ( Q 3 ) in the silicate chains of C-S-H gel at 1-day hydration. « less

  2. LyMAS: Predicting Large-Scale Lyman-alpha Forest Statistics from the Dark Matter Density Field

    E-Print Network [OSTI]

    Peirani, Sébastien; Colombi, Stéphane; Blaizot, Jérémy; Dubois, Yohan; Pichon, Christophe

    2013-01-01

    [abridged] We describe LyMAS (Ly-alpha Mass Association Scheme), a method of predicting clustering statistics in the Ly-alpha forest on large scales from moderate resolution simulations of the dark matter distribution, with calibration from high-resolution hydrodynamic simulations of smaller volumes. We use the "Horizon MareNostrum" simulation, a 50 Mpc/h comoving volume evolved with the adaptive mesh hydrodynamic code RAMSES, to compute the conditional probability distribution P(F_s|delta_s) of the transmitted flux F_s, smoothed (1-dimensionally) over the spectral resolution scale, on the dark matter density contrast delta_s, smoothed (3-dimensionally) over a similar scale. In this study we adopt the spectral resolution of the SDSS-III BOSS at z=2.5, and we find optimal results for a dark matter smoothing length sigma=0.3 Mpc/h (comoving). In extended form, LyMAS exactly reproduces both the 1-dimensional power spectrum and 1-point flux distribution of the hydro simulation spectra. Applied to the MareNostrum ...

  3. ARM - Campaign Instrument - mas

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.TheoryTuesday,air Comments?govInstrumentsmaeri Comments? We would love to hear

  4. 2.10 Multiscale Actuated Sensing (MAS) Multiscale actuated sensing research activities have focused on the core algorithmic challenges of incorporating rich

    E-Print Network [OSTI]

    Soatto, Stefano

    2.10 Multiscale Actuated Sensing (MAS) Multiscale actuated sensing research activities have focused on the trajectory design process for underwater vehicles. We take an Informative Path Planning approach to the robot path-planning problem. We aim to choose measurements that best describe a scalar field of interest (e

  5. Simultaneous optical speckle masking and NIR adaptive optics imaging of the 126 mas Herbig Ae/Be binary star NX Puppis

    E-Print Network [OSTI]

    Markus Schöller; Wolfgang Brandner; Thomas Lehmann; Gerd Weigelt; Hans Zinnecker

    1996-06-09

    We present simultaneous optical and near-infrared high angular resolution observations of the close Herbig Ae/Be binary star NX Pup which is associated with cometary globule~1. The reconstructed images have a diffraction--limited resolution of 62 mas in V, 75 mas in R (speckle masking reconstruction), and 115 mas in H, 156 mas in K (adaptive optics + post--processing). Compared to previous results we were able to derive better estimates on spectral type and luminosity and hence put better constraints on the evolutionary status (mass & age) of NX Pup A and B: with NX Pup A of spectral type F0-F2 we estimate the spectral type of NX Pup B in the range F7-G4, masses of 2 M$_\\odot$ and 1.6--1.9 M$_\\odot$, respectively, and an age of 3--5~Myr for both stars. We discuss the implication of the new age determination on the physical relation between NX Pup and the cometary globule. The dynamical lifetime of $\\approx$ 10$^6$ yr for cometary globule 1 suggests that cometary globule 1 and the nearby cometary globule 2 represent transient phenomena and are left overs of a larger molecular cloud which in turn was the parental cloud of NX~Pup A and B and finally got dispersed by photoevaporation. The IR excess of NX Pup A can be modeled by a viscous accretion disk, which is cut off at $\\approx$ 20 AU from the star. NX Pup B has a smaller IR excess which indicates that there is less circumstellar material present than around the primary.

  6. Obtaining aluminas from the thermal decomposition of their different precursors: An {sup 27}Al MAS NMR and X-ray powder diffraction studies

    SciTech Connect (OSTI)

    Chagas, L.H.; De Carvalho, G.S.G.; San Gil, R.A.S.; Chiaro, S.S.X.; Leitão, A.A.; Diniz, R.

    2014-01-01

    Graphical abstract: - Highlights: • We synthesized three precursors of alumina from different methods. • The calcination of the precursors generated several alumina polymorphs. • XRD and NMR were used for structural investigation of the polymorphs. • The synthesis route determines the structural and textural properties of the solids. - Abstract: A commercial sample of Boehmite was used as precursor of alumina polymorphs. For comparison, three other precursors were synthesized from different methods. Particularly, the use of excess of urea promoted a very crystalline form of basic aluminum carbonate. The characteristics of the four precursors were investigated by thermal, vibrational and X-ray powder diffraction (XRD) analysis. Additionally, the nuclear magnetic resonance, with magic angle spinning ({sup 27}Al MAS NMR), was used to verify the coordination of aluminum cations. Each precursor was calcined at various temperatures generating alumina polymorphs, which were structurally analyzed by XRD and {sup 27}Al MAS NMR. Due to interest in catalysis supports, special attention was given to the ?-Al{sub 2}O{sub 3} phase, which in addition to structural investigation was subjected to textural analysis. The results showed that, from different synthesis procedures and common route of calcination, one can obtain materials with the same composition but with different structural and textural properties, which in turn can significantly influence the performance of a supported catalyst.

  7. Robotic Helicopter Surveying (MAS 13)

    E-Print Network [OSTI]

    Srikanth Saripalli; Jonathan Kelly; Gaurav S. Sukhatme

    2006-01-01

    for Embedded Networked Sensing Robotic Helicopter Surveyingand Gaurav S. Sukhatme Robotic Embedded Systems Laboratory,

  8. MAS-NMR investigations of the crystallization behaviour of lithium aluminum silicate (LAS) glasses containing P{sub 2}O{sub 5} and TiO{sub 2} nucleants

    SciTech Connect (OSTI)

    Ananthanarayanan, A.; Kothiyal, G.P.; Montagne, L.; Revel, B.

    2010-06-15

    Lithium aluminum silicate (LAS) glass of composition (mol%) 20.4Li{sub 2}O-4.0Al{sub 2}O{sub 3}-68.6SiO{sub 2}-3.0K{sub 2}O-2.6B{sub 2}O{sub 3}-0.5P{sub 2}O{sub 5}-0.9TiO{sub 2} was prepared by melt quenching. The glass was then nucleated and crystallized based on differential thermal analysis (DTA) data and was characterized by {sup 29}Si, {sup 31}P, {sup 11}B and {sup 27}Al MAS-NMR. XRD and {sup 29}Si NMR showed that lithium metasilicate (Li{sub 2}SiO{sub 3}) is the first phase to c form followed by cristobalite (SiO{sub 2}) and lithium disilicate (Li{sub 2}Si{sub 2}O{sub 5}). {sup 29}Si MAS-NMR revealed a change in the network structure already for the glasses nucleated at 550 {sup o}C. Since crystalline Li{sub 3}PO{sub 4}, as observed by {sup 31}P MAS-NMR, forms concurrently with the silicate phases, we conclude that crystalline Li{sub 3}PO{sub 4} does not act as a nucleating agent for lithium silicate phases. Moreover, {sup 31}P NMR indicates the formation of M-PO{sub 4} (M=B, Al or Ti) complexes. The presence of BO{sub 3} and BO{sub 4} structural units in all the glass/glass-ceramic samples is revealed through {sup 11}B MAS-NMR. B remains in the residual glass and the crystallization of silicate phases causes a reduction in the number of alkali ions available for charge compensation. As a result, the number of trigonally coordinated B (BO{sub 3}) increases at the expense of tetrahedrally coordinated B (BO{sub 4}). The {sup 27}Al MAS-NMR spectra indicate the presence of tetrahedrally coordinated Al species, which are only slightly perturbed by the crystallization. - Graphical abstract: {sup 11}B MAS-NMR spectra of LAS glass heat treated at different temperatures, showing the evolution of the residual glass matrix during the crystallization treatment. High-field (18.8 T) NMR enables us to record high resolution spectra, from which the glass network modifications could be related to the formation of intermediate lithium silicate crystalline phases.

  9. H mais licenciados mas estamos longe

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    2013, registando um au- mento de dois pontos percentuais em relação ao ano anterior. O valor continua amostra de jovens entre os 18 e os 24 anos, indicam um valor de abandono escolar de 19,2%. Um recuo em por motivos financeiros a retomarem os estudos. O programa funcionará através da atribuição de bolsas

  10. MAS 2: Multiscale Actuated Sensing Theory

    E-Print Network [OSTI]

    Xiangming Kong; William Kaiser; Greg Pottie

    2006-01-01

    data Observer Leaf Shading leaf Simulate solar radiationdata to establish models under all conditions Geometry determines direct solar radiation

  11. MAS 552.J / 4.557J MIT Living Labs

    E-Print Network [OSTI]

    innovations that including new lightweight electric vehicles, electric charging and smart grid technologies) the CityHome. MoD systems consist of a fleet of Lightweight Electric Vehicles (LEVs) distributed that tackle the "First and Last Mile" problem of public transit systems. The CityCar designed by the Changing

  12. MAS.962 Autism Theory and Technology, Spring 2007

    E-Print Network [OSTI]

    Breazeal, Cynthia

    This course will lay a foundation in autism theory and autism technology that significantly leverages and expands the Media Lab's ability to pioneer new technology. Students will not only develop new technologies, but also ...

  13. MAS 108 Probability I Notes 1 Autumn 2005

    E-Print Network [OSTI]

    Bailey, R. A.

    .) If I toss a coin three times and record the results of the three tosses, the sample space is S = {HHH' and B the event `tails on last throw'. Then A = {HHH,HHT,HTH,THH}, B = {HHT, it is {HHH}). If A = {a} is a simple event, then the proba- bility of A is just the probability

  14. MAS 108 Probability I Notes 4 Autumn 2005

    E-Print Network [OSTI]

    Bailey, R. A.

    of paying. The sample space is S = {HHH,HHT,HTH,HTT,THH,THT,TTH,TTT}, and the events `Alice pays' and `Bob pays' are respectively A = {HHH,HHT,HTH,THH}, B = {HTT,THT,TTH,TTT}. They toss the coin once and the result is heads; call this event E. How should we now reassess their chances? We have E = {HHH

  15. MAS.110 Fundamentals of Computational Media Design, Spring 2003

    E-Print Network [OSTI]

    Maeda, John

    Introduces principles of analysis and synthesis in the computational medium. Expressive examples that illustrate the intersection of computation with the traditional arts are developed on a weekly basis. Hands-on design ...

  16. QUEEN MARY, UNIVERSITY OF LONDON MAS 314 Design of Experiments

    E-Print Network [OSTI]

    Bailey, R. A.

    water. After three months, he will remove all the metal components from the tank, and measure the amount or enclosed in a document wallet. The pages of computer output should be separated and should be labelled (by in the construction of underwater structures at sea, such as piers and oil-drilling platforms. He wants to protect

  17. MAS308 Chaos and Fractals 2004-2005 Learning Outcomes

    E-Print Network [OSTI]

    Bullett, Shaun

    such as the doubling map on the circle and the logistic map. 9. Know how to use iterated function systems to generate. Describe the main features of the bifurcation diagram for the logistic family of maps, and compute the parameter values of key points in this diagram. 6. Understand conjugacies between maps and compute them

  18. Stereo Vision Aided Navigation for Robotic Boats (MAS 10)

    E-Print Network [OSTI]

    2006-01-01

    Micropix Color camera Above: Buoy as Imaged by the ColorCamera. Above: Buoy and Robot Boat at Lake Fulmor. Whybf ? ? d Methodology Segment buoy using color blob and edge-

  19. MAS 10.3 Seasonal Preparation 3/21/95

    Broader source: Energy.gov [DOE]

    The objective of this surveillance is to verify that the contractor is implementing appropriate measures to protect equipment and systems from damage due to the effects of cold weather.  The...

  20. Scheduling on the MasPar SIMD parallel computer 

    E-Print Network [OSTI]

    Perkins, Keith Douglas

    1995-01-01

    This thesis studies the feasibility of a task scheduler for a parallel operating system. After analyzing several task scheduling algorithms, the highest level first algorithm was chosen. This algorithm has been empirically found to build schedules...

  1. Stereo Vision Aided Navigation for Robotic Boats (MAS 10)

    E-Print Network [OSTI]

    2006-01-01

    A docking system for a robotic boat using stereo vision foraided Navigation for Robotic Boats Arvind Menezes Pereira,Moorthi and David Caron. Robotic Embedded Systems Lab,

  2. www.mas.ecp.fr Director: Frdric Abergel

    E-Print Network [OSTI]

    Bezerianos, Anastasia

    A digipl AnTe projeCT Te Am) Modelling and estimation of the dynamic system of plants in their environment restoration with numerical models iNDusTRial paRTNeRs BNP Paribas, SAP-BusinessObjects, Alcatel, Bionatics, simulation, analysis, optimization and visualization of complex systems, whether they come from

  3. Juntos, ms fuertes, mas lejos... Toulouse Midi-Pyrenees

    E-Print Network [OSTI]

    Bordenave, Charles

    , economía, gestión) · Université Toulouse II Le Mirail (artes,letras, lenguas, ciencias humanas francesa : la Toulouse School of Economics (Ecole d'Economie de Toulouse - Escuela de economía de Toulouse

  4. MAS.836 Sensor Technologies for Interactive Environments, Spring 2010

    E-Print Network [OSTI]

    Paradiso, Joseph

    This course is a broad introduction to a host of sensor technologies, illustrated by applications drawn from human-computer interfaces and ubiquitous computing. After extensively reviewing electronics for sensor signal ...

  5. Deep water X-mas tree standardization -- Interchangeability approach

    SciTech Connect (OSTI)

    Paula, M.T.R.; Paulo, C.A.S.; Moreira, C.C.

    1995-12-31

    Aiming the rationalization of subsea operations to turn the production of oil and gas more economical and reliable, standardization of subsea equipment interfaces is a tool that can play a very important role. Continuing the program initiated some years ago, Petrobras is now harvesting the results from the first efforts. Diverless guidelineless subsea Christmas trees from four different suppliers have already been manufactured in accordance to the standardized specification. Tests performed this year in Macae (Campos Basin onshore base), in Brazil, confirmed the interchangeability among subsea Christmas trees, tubing hangers, adapter bases and flowline hubs of different manufacturers. This interchangeability, associated with the use of proven techniques, results in operational flexibility, savings in rig time and reduction in production losses during workovers. By now, 33 complete sets of subsea Christmas trees have already been delivered and successfully tested. Other 28 sets are still being manufactured by the four local suppliers. For the next five years, more than a hundred of these trees will be required for the exploration of the new discoveries. This paper describes the standardized equipment, the role of the operator in an integrated way of working with the manufacturers on the standardization activities, the importance of a frank information flow through the involved companies and how a simple manufacturing philosophy, with the use of construction jigs, has proved to work satisfactorily.

  6. Variations du nombre de grains chez diffrents gnotypes de mas

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    dates of sowing, use of plastic mulch). Row number was not modified by environmental condi- tions, présence ou non de mulch plastique (au total 22 conditions différentes). Pour un génotype donné, le nombre en zone sep- tentrionale, à différentes dates et avec, dans certains cas, un mulch plastique destiné

  7. 6.868J / MAS.731J The Society of Mind, Spring 2007

    E-Print Network [OSTI]

    Minsky, Marvin

    This course is an introduction to a theory that tries to explain how minds are made from collections of simpler processes. The subject treats such aspects of thinking as vision, language, learning, reasoning, memory, ...

  8. MAS.160 Signals, Systems, and Information for Media Technology, Fall 2001

    E-Print Network [OSTI]

    Massachusetts Institute of Technology. Media Laboratory.

    Fundamentals of signals, systems, and information theory with emphasis on modeling both the audio/visual message and the human recipient. Linear systems, difference equations, Z-transforms, sampling and sampling rate ...

  9. MAS.714J / STS.445J Technologies for Creative Learning, Fall 2004

    E-Print Network [OSTI]

    Resnick, Mitchel

    This course explores how new technologies can help people learn new things in new ways. It analyzes principles and strategies underlying the design of innovative educational technologies and creative learning environments, ...

  10. High field DNP and cryogenic MAS NMR : novel instrumentation and applications

    E-Print Network [OSTI]

    Markhasin, Evgeny

    2014-01-01

    Solid State Nuclear Magnetic Resonance (ssNMR) spectroscopy has blossomed over the last two decades. As ssNMR is progressively applied to more challenging systems, the sensitivity remains one of its major limiting factors. ...

  11. MAS250 1 Turn over SCHOOL OF MATHEMATICS AND STATISTICS Autumn Semester

    E-Print Network [OSTI]

    = . (12 marks) (b) A sample of 20 lightbulbs had the following lifetimes (in weeks, rounded to the nearest

  12. loannis Tomkos, Dimitrios Vogiatzis, Carmen Mas, loannis Zacharopoulos, Anna Tzanakaki, and Emmanovel Varvarigos

    E-Print Network [OSTI]

    Varvarigo, Emmanouel "Manos"

    of technology and architectures toward a more flexible and intelligent optical network layer based on the use introduced by the transmission line or switching equipment. Network designers may overcome the impact engineering of transparent metropolitan area optical networks. Our results show the relationship between

  13. Gii thiu v trng UMass Amherst l trng ni ting trong h thng i Hc Mas-

    E-Print Network [OSTI]

    Massachusetts at Amherst, University of

    trng i hc vi 60% s sinh viên i hc ti các khu ký túc xá trong trng và thng thc các món n cng tin. Cng hc ca trng cng c ánh giá rt cao. Bng xp hng 5.000 chng trình tin s nm 2010 ca y Ban Nghiên Cu Quc Gia hc t thc. Tám ngành hc khác cng rt ni ting là: công ngh sinh hc ng vt, hóa k thut, hóa hc, công ngh

  14. NIMS3D: An Autonomous Three-Dimensional Cabled Robot for Actuated Sensing Applications (MAS 3)

    E-Print Network [OSTI]

    Per Henrik Borgstrom; Nils Peter Borgstrom; Michael J. Stealey; Maxim A. Batalin; William J. Kaiser

    2006-01-01

    Laser Rangefinder Topographic Lab Test: 12/2/05 z-pos (m)y-pos (m)x-pos (m) Piecewise linear trajectory – Trace of x

  15. Kelly C. Lee, Pharm.D., MAS, BCPP Why do a residency?

    E-Print Network [OSTI]

    Gleeson, Joseph G.

    /work? Can I afford to live away from home? What are the benefits? Number of residents in the program or focus on preparing for specialty residencies or fellowships 5 #12;Reality Check Where do I want to live Are there support systems? Will I miss the sunny weather in San Diego? 6 #12;Benefits of Residency Training Gets

  16. NuMas: A LAN-based materials control and accounting system in production

    SciTech Connect (OSTI)

    Strickland, T.W.; Bracey, J.T.; McMahon, S.A. [Lockheed Martin Utility Services, Inc., Paducah, KY (United States). Paducah Gaseous Diffusion Plant

    1995-12-31

    A state-of-the-art Nuclear Materials Control and Accounting (NMC and A) System has been implemented and is fully operational at the Paducah Gaseous Diffusion Plant (PGDP) as of September 1994. The uranium enrichment facility is currently regulated by the Department of Energy (DOE) and is in the process of obtaining Nuclear Regulatory Commission (NRC) certification. Implementation of this system has resulted in a tremendous cost savings to the facility as well as improvements to the overall efficiency of the NMC and A department. This paper outlines the benefits of implementing a Personal Computer/Local Area Network (PC/LAN)-based system in hopes of attracting other facilities to explore and utilize its application at their sites.

  17. Dipolar Recoupling in MAS NMR: A Probe for Segmental Order in Lipid Bilayers

    E-Print Network [OSTI]

    Griffin, Robert G.

    to that of the 2H electric field gradient tensor and it is possible to record natural abundance 13C spectra other spin interactions such as dipolar couplings and chemical shifts, interpretation of 13C- 1H dipolar

  18. A Prolog-Based MAS for Railway Signalling Monitoring: Implementation and Experiments

    E-Print Network [OSTI]

    Mascardi, Viviana

    [12]) was Europe's largest ever project in the area of Distributed Artificial Intelligence. It was em energy to industrial and domestic customers, for the Iberdrola company, one of the world's leading private energy groups [8]. ARCHON's Planning and Coordination Module was implemented as a rule- based

  19. Dure des phases vgtative et reproductrice chez le mas. Influence du gnotype et du milieu

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    with or without plastic mulch).' Soil ' temperature was more representative than 'air temperature ' to explain, dates of sowing, plastic mulch. I. INTRODUCTION Le cycle du maïs est constitué d'une succession de années, semis décalés, sol couvert ou non de mulch plastique. La vitesse de développement jusqu'à l

  20. SoMAS alumni have gone on to careers as: Acting Director, NY Sea Grant

    E-Print Network [OSTI]

    Zhang, Minghua

    , Energy and Environmental Analysts, Inc., Stony Brook, NY · Marine Technical Associate, School of Marine & Facilities Specialist, NY Sea Grant Extension · Director, Center for Marine & Wetland Studies, Conway, SC · Environmental Affairs Officer on Marine & Coastal Biodiversity, UNEP Secretariat of Convention on Biological

  1. Problem Set 3 MAS 622J/1.126J: Pattern Recognition and Analysis

    E-Print Network [OSTI]

    samples from class 1 x1 = dd(:,1); % test samples from class 2 x2 = dd(:,2); Pd_save = []; Pf_save(x > x_c | x in w=1) Pf = nFP / num_samples; Pd_save = [Pd_save; Pd]; Pf_save = [Pf_save; Pf]; end mean1 - mean2)/sig % d' figure hold on plot(Pf_save, Pd_save, 'r') 2 #12;sprintf('dataset2:') dd = load

  2. MAS 108 Probability I In-term Test 10 November 2004, 12:10pm12:55pm

    E-Print Network [OSTI]

    Bailey, R. A.

    university, 60% of the students play football, 40% play cricket, 30% swim, 20% play both football and cricket, 15% play football and swim, 5% play cricket and swim, and 1% swim and play both football and cricket football or plays cricket or swims? Let F = "student plays football", C = "student plays cricket

  3. A comparison of cloud top heights computed from airborne lidar and MAS radiance data using CO2 slicing

    E-Print Network [OSTI]

    Sheridan, Jennifer

    with dual polarization at 0.532 m. The comparisons were performed for 10 flight days during the Subsonic specification of clear-sky radiances. 1. Introduction Clouds have a large impact on the Earth's water and energy budgets. Their impact on the radiation budget can result in a heating or in a cooling of the planet

  4. Quantitative metabolic profiles of 2nd and 3rd trimester human amniotic fluid using 1H HR-MAS spectroscopy

    E-Print Network [OSTI]

    2009-01-01

    metabolic pro?les of 2nd and 3rd trimester human amniotic ?concentrations in 2nd and 3rd trimester human amniotic ?uidweeks gestation, N = 23) and 3rd (29–39 weeks gestation, N =

  5. FTIR and 27 Al MAS NMR analysis of the effect of framework Al-and Si-defects

    E-Print Network [OSTI]

    Sklenak, Stepan

    longer catalyst life-time. The micro-mesoporous H-ZSM-5 (synthesized by using carbon particles) exhib NMR and FTIR spectroscopy of OH groups and C,,N groups of adsorbed d3-acetonitrile were used, and particularly much lower catalyst life-time compared to the sample of similar composition and synthesis

  6. Mujer Mas Segura (Safer Women): A combination prevention intervention to reduce sexual and injection risks among female sex workers who inject drugs

    E-Print Network [OSTI]

    2012-01-01

    i.e. , cotton filter, cookers, rinse water) that had beena cooker, cotton filter, or rinse water to prepare drugs fora cooker, cotton filter, or rinse water to prepare drugs for

  7. Pasos a Seguir Despues de Haber Sido Admitido Nos alegra tenerle como un "Aguila" (Eagle) mas. Por favor, asegurese de seguir los

    E-Print Network [OSTI]

    Hutcheon, James M.

    - cluidos en tu cuenta de Georgia Southern incluyen EAGLEXPRESS, comida, gasolina o gastos fuera del campus

  8. The transition from water to land is one of the most fascinating enig-mas of evolution. In particular, the evolution of limbs from ances-

    E-Print Network [OSTI]

    Halazonetis, Thanos

    . In particular, the evolution of limbs from ances- tral fish fins remains a mystery. Both fish and land animals similar 3-dimensional DNA or- ganization of the fish and mouse clusters, which indicates that the main mechanism used to pattern tetrapod limbs was already pres- ent in fish. However, when inserted

  9. Perfil de la Universidad Georgia Southern Georgia Southern fue fundada en 1906 y, con algo mas de 20,000 estudiantes, es una de

    E-Print Network [OSTI]

    Hutcheon, James M.

    , Ciencias Naturales, Inform´atica, Artes Liberales, Ciencias Sociales, Salud P´ublica, Ciencia, Tecnolog Savannah. La instituci´on cuenta con modernos y c´omodos edificios equipados con todo tipo de tecnolog

  10. Migration, Displacement, and Movements in the Global Space: Ming-Yuen S. Ma’s Multi-Media Project Xin Lu: A Travelogue in Four Parts

    E-Print Network [OSTI]

    Zhou, Xiaojing

    2012-01-01

    workers building the transcontinental railroad, and makingcompletion of the transcontinental railroad which dependedthe completion of the transcontinental railroad in 1869.

  11. J. Am. Chem. SOC.1988, 110, 3829-3835 3829 between I3CCP/MAS spectra of amorphous starches and V-type

    E-Print Network [OSTI]

    Smith, Bradley D.

    -ethyl-, 2-n-propyl-, 2-isopropyl-, 2-tert-butyl-, 2-(methoxymethyl), 3,5-dimethyl-,3,5-dimethyl-4-methoxy-,4-chloro-3,5-dimethyI-, 3,5-diethyl-, and 3,5-dimethoxyphenolates in solution in weakly polar-') are found for 2 dimer *tetramer: lithium 4-bromophenolate (THF), 4.4 f 0.5,24 & 2; 3,5-dimethylphenolate

  12. Petrovay K. TURBULENCIA INHOMOG '

    E-Print Network [OSTI]

    Petrovay, Kristóf

    TLM -- la m'as sencilla pos'ible, no m'as ecu. dif. -- s'olo para calcular estratificaci'on termodin'amica

  13. 99129-5/2002-DR/SC Universidade Federal de Santa Catarina -Novembro de 2007 -N 386

    E-Print Network [OSTI]

    Floeter, Sergio Ricardo

    "? Curiosidade. Segundo o Google, o termo mais bus- cado pelos internautas é neoliberalismo. Melhorou, mas... Um

  14. www.worldscientific.com World Scientific

    E-Print Network [OSTI]

    Hart, Sergiu

    AtegieS World Scientific Series in Economic Theory ­ Vol. 4 Sergiu Hart Andreu Mas-Colell Hart Mas-Colell Vol. 4 of joint work of Sergiu Hart and Andreu Mas-Colell on game dynamics and equilibria. The starting point, is to define the process by which equilibrium is attained. The work of Professors Hart and Mas-Colell has been

  15. Accounting for Children's Illnesses: Epistemics and Social Relations in Mapuche Healing and Chilean Primary Care Medicine

    E-Print Network [OSTI]

    Guzman, Jennifer Rhae

    2012-01-01

    alterados. disturbed. HEALER .hhh y mas se le inflaman unpoco las manos, los pies. .hhh and more the hands, the feetalterados. disturbed. HEALER .hhh y mas se le inflaman un

  16. Journal of Machine Learning Research 16 (2015) ?-? Submitted 10/13; Revised 7/14; Published 4/15 Response-Based Approachability with Applications to

    E-Print Network [OSTI]

    Shimkin, Nahum

    2015-01-01

    considered, among others, in Vieille (1992); Shimkin and Shwartz (1993); Hart and Mas-Colell (2001); Spinat (Foster, 1999), and con- vergence to correlated equilibria (Hart and Mas-Colell, 2000). An application

  17. Design, analysis, and testing of a precision guidance, navigation, and control system for a dual-spinning Cubesat

    E-Print Network [OSTI]

    Wise, Evan Dale

    2013-01-01

    The Microsized Microwave Atmospheric Satellite (MicroMAS) combines two traditional control approaches: a dual spinner and a three-axis gyrostat. Unlike typical dual spinners, the purpose of MicroMAS 's 2U bus and spinner ...

  18. Desertion of the colonists of New Mexico 1601: 2d part

    E-Print Network [OSTI]

    Carlin, A. Roberta; De Marco, Barbara; Craddock, Jerry R; Polt, John H. R.

    2013-01-01

    veera lo que mas convenga e ansi lo proveyo e mando e firmoque biniesen mas cas- tillas que ansi nos llaman ellos y quelas mugeres e haziendas, ansi capitanes como rreligiosos, y

  19. Contributors 20:3

    E-Print Network [OSTI]

    2008-01-01

    Architecture and Planning of the Mas- sachusetts Institute of Technology,architecture at the Massachusetts Institute of Technology.

  20. A Changing Planet Over the past century, the average global tempera-

    E-Print Network [OSTI]

    tons of hydrogen fuse into helium within the sun's core as part of a mas- sive chain of thermonuclear

  1. María Luz Reyes and Florentino Collazo: La Milpa Organic Farm

    E-Print Network [OSTI]

    Rabkin, Sarah

    2010-01-01

    mas de tres cultivos, tenemos hasta 25. I: Biodiversidad?COLLAZO: Biodiversidad. Entonces el concepto esta bien dicho

  2. Astronomy & Astrophysics manuscript no. lupc2dspec270313 c ESO 2013 April 2, 2013

    E-Print Network [OSTI]

    Comerón, Fernando

    of youth. Many of them relate to the presence of mas- sive circumstellar disks and envelopes that reprocess

  3. 2-LAMA Architecture vs. BitTorrent Protocol in a Peer-to-Peer Scenario

    E-Print Network [OSTI]

    López-Sánchez, Maite

    2-LAMA Architecture vs. BitTorrent Protocol in a Peer-to-Peer Scenario Jordi CAMPOS a&1 , Maite review our Multi-Agent System (MAS) architecture (2- LAMA) proposed to assist existing MAS. This architecture consists of two levels: the conventional MAS system and an additional meta-level in charge

  4. Leader Selection in Multi-Agent Systems for Smooth Convergence via Fast Mixing Andrew Clark, Basel Alomair, Linda Bushnell, and Radha Poovendran

    E-Print Network [OSTI]

    Poovendran, Radha

    random link failures and a MAS that switches between predefined topologies. We compare our leader (MAS) consists of a group of agents, each of which controls its own state based on the state changes over time [1]. Applications of MAS range from autonomous aerial and ground vehicles [2

  5. APRENDIENDO DE GRASAS APRENDIENDO DE GRASAS

    E-Print Network [OSTI]

    Zhou, Chongwu

    QUE LOS BENEFICIOS DE TENER MAS MÚSCULO ES SIMBOLIZADO COMO UNA LUZ "VERDE." HAY MUCHOS BENEFICIOS DE SEGUIR. HAY QUE IMAGINARNOS QUE LAS BARRERAS A TENER MAS MÚSCULO ES SIMBOLIZADO COMO UNA LUZ "ROJA DE VIDA NUTRICIONAL MAS SANO. QUEREMOS ESTAR SEGUROS QUE SU LUZ VERDE SIEMPRE BRILLE BRILLANTE

  6. A Tractable Approach to Understanding the Results from Large-Scale 3D Transient

    E-Print Network [OSTI]

    Peraire, Jaime

    ) problems or NASA's HPCC (High Performance Computing & Communication) grand challenges, can easily. Introduction Large-scale simulations of physical phenomena on high performance computing systems (often on mas

  7. O legado filos'ofico de John von Neumann

    E-Print Network [OSTI]

    Kohayakawa, Yoshiharu

    inventor n~ao era um engenheiro eletrâ??onico, mas sim um matem'atico, e essa foi a ' unica patente de John

  8. Does the Effect of Pollution on Infant Mortality Differ Between Developing and Developed Countries? Evidence from Mexico City

    E-Print Network [OSTI]

    Arceo, Eva; Hanna, Rema; Oliva, Paulina

    2012-01-01

    could affect both pollution levels and infant mortality. Therelationship between pollution (! !" ) in a municipality (m)as very suggestive. pollution may be richer, and thus have

  9. DESIGN AND FABRICATION OF A ROLLER IMPRINTING DEVICE FOR MICROFLUIDIC DEVICE MANUFACTURING

    E-Print Network [OSTI]

    Vijayaraghavan, Athulan; Jayanathan, Stephen; Helu, Moneer; Dornfeld, David

    2008-01-01

    a mas- ter made of thermoplastic build material [18].400 x 600 DPI), and the thermoplastic build material is soft

  10. Automatic Microaneurysm Detection and Characterization Through Digital Color Fundus Images

    E-Print Network [OSTI]

    Martins, Charles

    2010-01-01

    and M. D. Abr` moff. Automatic detection of red a lesions inAutomatic Microaneurysm Detection and Characterizationimportant task in the automatic MAs characterization scheme.

  11. El espa�ol de California en el XIX

    E-Print Network [OSTI]

    Lamar Prieto, Maria Covadonga

    2012-01-01

    igual   dar  Francisco  Palomares  por  la  Can   tidad  caen  sobre  el  fiador  Palomares,   mas  este  dize  que  á   el  mensionado  Palomares,  aquien  le   le  hize  

  12. CUTANEOUS WATER LOSS AND LIPIDS OF THE STRATUM CORNEUM IN DUSKY ANTBIRDS, A LOWLAND

    E-Print Network [OSTI]

    Williams, Jos. B.

    estrato co´rneo, la capa ma´s externa de la epidermis, esta´ formado por ce´lulas aplanadas embebidas en

  13. Comparative analysis of black carbon in soils

    E-Print Network [OSTI]

    2001-01-01

    mass difference, demineralization HF (2%) I•C MAS NMRexcept for a final demineralization step (HF) beforecarried out following demineralization. Although the number

  14. María Inés Catalán: Catalán Family Farm

    E-Print Network [OSTI]

    Reti, Irene H.

    2010-01-01

    m not going to put even a penny more into the ranch. You allal rancho no le voy a poner un penny mas. Ustedes tienen que

  15. NUEVOS DATOS SOBRE UN ENDEMISMO HALLADO HACE POCOS ANOS Trit6n del Montseny

    E-Print Network [OSTI]

    Carranza, Salvador

    NUEVOS DATOS SOBRE UN ENDEMISMO HALLADO HACE POCOS ANOS Trit6n del Montseny: el anfibio mas conservacion de su habitat, un tercero de crfa ex situ y un cuarto para esclare- cer su origen, evolucion y ecologicas. Es mas, cada uno de esos nucleos 10 ocupan ejem- plares morfologicamente diferentes en base a su

  16. Direct Speciation of Phosphorus in Alum-Amended Poultry Litter

    E-Print Network [OSTI]

    Sparks, Donald L.

    Direct Speciation of Phosphorus in Alum-Amended Poultry Litter: Solid-State 31 P NMR Investigation prerequisite for the assessment of the sustainability of intensive poultry operations. Both solid- state MAS and CP-MAS 31P NMR as well as 31P{27Al}- TRAPDOR were used to investigate P speciation in alum- amended

  17. DEVELOPMENT OF MULTIPLE SAMPLE SOLID-STATE NMR PROBES FOR ANALYSIS OF PHARMACEUTICAL COMPOUNDS AND FORMULATIONS

    E-Print Network [OSTI]

    Nelson, Benjamin Nels

    2011-12-31

    developed. This version is limited to being a two-module probe due to the large amounts of space required for the tuning elements, which are located next to the MAS modules. A new probe design incorporating coaxial transmission lines and smaller MAS modules...

  18. -A Science Service Featuse Beleased upon receipt

    E-Print Network [OSTI]

    of ball lightning, every m a i l has brcue;ht letters on the sllbject to Dr. Hwphreys, of the eath her, probably of ozone, mas noticed. The ball passed out "he troe mas not (All rights reserved by Science

  19. Di erential Astrometry of Sub-arcsecond Scale Binaries at the Palomar Testbed Interferometer

    E-Print Network [OSTI]

    Di#11;erential Astrometry of Sub-arcsecond Scale Binaries at the Palomar Testbed Interferometer B, Cambridge, MA 02139 blane@mit.edu matthew1@mit.edu ABSTRACT We have used the Palomar Testbed Interferometer at the 10 mas (1 mas = 10 3 arcseconds) level (Hum- mel et al. 1994), while the Palomar Testbed

  20. HST Fine Guidance Sensor Astrometric Parallaxes for Three Dwarf Novae: SS Aurigae, SS Cygni, and U Geminorum

    E-Print Network [OSTI]

    Thomas E. Harrison; Bernard J. McNamara; Paula Szkody; Barbara J. McAurthur; G. F. Benedict; Arnold R. Klemola; Ronald L. Gilliland

    1999-02-16

    We report astrometric parallaxes for three well known dwarf novae obtained using the Fine Guidance Sensors on the Hubble Space Telescope. We found a parallax for SS Aurigae of Pi = 5.00 +/- 0.64 mas, for SS Cygni we found Pi = 6.02 +/- 0.46 mas, and for U Geminorum we obtained Pi = 10.37 +/- 0.50 mas. These represent the first true trigonometric parallaxes of any dwarf novae. We briefly compare these results with previous distance estimates. This program demonstrates that with a very modest amount of HST observing time, the Fine Guidance Sensors can deliver parallaxes of unrivaled precision.

  1. Interdisciplinary Mathematics/Statistics Actuarial Science Sample ...

    E-Print Network [OSTI]

    Interdisciplinary Mathematics/Statistics Actuarial Science Sample Plan 2 . 1 MA 161 (4-5) MA/S T 170 ENGL 101 Lab Science Language or 165, 173, 181, 271 ...

  2. The Public Sphere of the Hunt Circle in Early Nineteenth-Century Politics and Culture 

    E-Print Network [OSTI]

    Min, Byoung Chun

    2010-07-14

    by a creative mental proces, and Lionel Triling celbrates Romantic literature as consummating an individual?s potential to liberate him/herself from the tyranny of mas culture.8 That is, the value of human natural felings became r...

  3. An analysis of response variation encountered with selected interviewing techniques in consumer marketing research 

    E-Print Network [OSTI]

    Courtenay, Henry V

    1960-01-01

    and Flavorful Mhen Direct Versus Indirect Questioning Mas Used By Age Groups. . . . . . . . . . . ~ . . . . . . 181 60. Distributions Mhen Direct Versus Indirect questions Mere Used in the Questions "Where Have You Seen This Credo LabelT". . . 187 61...

  4. Automatic Microaneurysm Detection and Characterization Through Digital Color Fundus Images

    SciTech Connect (OSTI)

    Martins, Charles; Veras, Rodrigo; Ramalho, Geraldo; Medeiros, Fatima; Ushizima, Daniela

    2008-08-29

    Ocular fundus images can provide information about retinal, ophthalmic, and even systemic diseases such as diabetes. Microaneurysms (MAs) are the earliest sign of Diabetic Retinopathy, a frequently observed complication in both type 1 and type 2 diabetes. Robust detection of MAs in digital color fundus images is critical in the development of automated screening systems for this kind of disease. Automatic grading of these images is being considered by health boards so that the human grading task is reduced. In this paper we describe segmentation and the feature extraction methods for candidate MAs detection.We show that the candidate MAs detected with the methodology have been successfully classified by a MLP neural network (correct classification of 84percent).

  5. Diameters of delta Cephei and eta Aquilae Measured with the Navy Prototype Optical Interferometer

    E-Print Network [OSTI]

    J. T. Armstrong; Tyler E. Nordgren; M. E. Germain; Arsen R. Hajian; R. B. Hindsley; C. A. Hummel; D. Mozurkewich; R. N. Thessin

    2000-09-25

    We have measured the diameters of the Cepheid variables delta Cephei (18 nights) and eta Aquilae (11 nights) with the Navy Prototype Optical Interferometer. The primary results of these observations are the mean angular diameters of these Cepheids: 1.520 +/- 0.014 milliseconds of arc (mas) for delta Cep and 1.69 +/- 0.04 mas for eta Aql. We also report limb-darkened diameters for the check stars in this program: for beta Lac, theta(LD) = 1.909 +/- 0.011 mas, and for 12 Aql, theta(LD) = 2.418 +/- 0.010 mas. When combined with radius estimates from period-radius relations in the literature, the Cepheid angular diameters suggest distances slightly smaller than, but still consistent with, the Hipparcos distances. Pulsations are weakly detected at a level of about 1.5 sigma to 2 sigma for both Cepheids.

  6. Un modelo matem'atico para la operaci'on 'optima de corto plazo de un sistema el'ectrico

    E-Print Network [OSTI]

    'on de m'as largo plazo para lograr un uso eficiente del agua de los embalses. Se asume conocida informaci'on detallada sobre la demanda, la disponibilidad de los generadores y los aportes externos de agua

  7. Expedition conducted in 1719 by Antonio Valverde Cossío, governor of New Mexico, to punish the Comanche and Ute Indians

    E-Print Network [OSTI]

    Polt, John H. R.

    2013-01-01

    paraje esta vna laguneta con agua y enfrente, a distanzia dequi- siera rrezeuirian el agua del Santo Bauptismo, de queenseñando los parajes y agua- jes mas commodos para que se

  8. BWR Assembly Optimization for Minor Actinide Recycling

    SciTech Connect (OSTI)

    G. Ivan Maldonado; John M. Christenson; J.P. Renier; T.F. Marcille; J. Casal

    2010-03-22

    The Primary objective of the proposed project is to apply and extend the latest advancements in LWR fuel management optimization to the design of advanced boiling water reactor (BWR) fuel assemblies specifically for the recycling of minor actinides (MAs).

  9. High-Resolution NMR of Quadrupolar Nuclei in a Solid State

    E-Print Network [OSTI]

    Gann, S.L.

    2010-01-01

    A 110,293-297 (1994). S. R. Hartmann and E. L. Hahn, Phys.a method for broadening the Hartmann-Hahn matching conditionspinning (MAS), making the Hartmann-Hahn matching conditions

  10. Data provided: Formula Sheet SCHOOL OF MATHEMATICS AND STATISTICS Spring Semester

    E-Print Network [OSTI]

    #12;MAS424 1 (i) In the Canadian wilds, mountain bears eat berries and catch salmon in the rivers, and the salmon eat various insects which live near the water surface. A simple model for the bear and salmon

  11. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    -7sup +9%, were detected with the VLBA at 5.0 GHz with peak flux densities above 6 sigma approx 2 mJy at 2 mas resolution. The VLBA detections occur through the full...

  12. Social Reasoning in Multi-Agent Systems with the Expectation-Strategy-Behaviour Framework 

    E-Print Network [OSTI]

    Wallace, Iain Andrew

    2010-01-01

    Multi-agent Systems (MAS) provide an increasingly relevant field of research due to their many applications to modelling real world situations where the behaviour of many individual, self-motivated, agents must be reasoned ...

  13. Desenvolvimento de um Sistema para Anlise da Variabilidade da Freqncia Cardaca

    E-Print Network [OSTI]

    Carvalho, João Luiz

    sinal de HRV utilizando um algoritmo de detecção automática dos complexos QRS. O usuário pode de HRV. Existem programas que implementam alguns dos algoritmos disponíveis, mas não todos eles

  14. Can Federal Funding Create Bicycle Friendly Cities? A Comparative Study of Bicycle Planning in Sacramento and Amsterdam

    E-Print Network [OSTI]

    2007-01-01

    of Bicycle Planning in Sacramento and Amsterdam KATHRYN M.as a model of how the Sacramento region can achieve highis on the area within Sacramento’s Metropolitan Planning

  15. INVESTIGATING THE EFFECT OF ENANTIOMERIC RATIO AND PREPARATION METHOD ON CRYSTALLINE FORMS OF PROLINE USING SOLID-STATE NMR SPECTROSCOPY

    E-Print Network [OSTI]

    Berendt, Robert Thomas

    2010-08-26

    was highly suited for investigating proline enantiomers in the solid state. Different solid forms, including crystal defects and amorphous material, possessed different peaks in 13C CP-MAS NMR spectra. Also, isotopic labeling, combined with spectral...

  16. Base de Datos TESEO Este frame debe obligatoriamente llamarse "win_system" y es un frame oculto habitualmente. Contiene las declaraciones de variables

    E-Print Network [OSTI]

    Carrete, Martina

    permitido establecer que, en la situación estudiada, la dinamica intraespecifica, mas que la interespecifica demograficos. Destaca, dentro del primer grupo, la importancia de incrementar la disponibilidad de habitat para

  17. 2/13/2014 Moinhos de vento anexados ao celular recarregam bateria -Pgina 2 -EXAME.com http://exame.abril.com.br/tecnologia/noticias/cientistas-criam-moinhos-de-vento-que-recarregam-bateria?page=2 1/3

    E-Print Network [OSTI]

    Chiao, Jung-Chih

    de uma casa para gerar energia elétrica. A WinMEMS chegou a firmar uma parceria com a universidade as propriedades intelectuais da invenção, mas deu à empresa a chance de explorá-la comercialmente. Ainda assim

  18. New World Songs for Catholic Saints: Domestic Performances of Devotion and History in Bahia, Brazil

    E-Print Network [OSTI]

    Iyanaga, Michael Zenryu

    2013-01-01

    room), educator Sandra Luz suggests that “La Farolera” is “de filhos que Maria deu à luz, nem quanto criou, mas sabemossetembro de 1917, Anna deu à luz o primeiro filho, Adalberto

  19. María Inés Catalán: Catalán Family Farm

    E-Print Network [OSTI]

    Reti, Irene H.

    2010-01-01

    My son, you have to put compost on it, and dig more, and mixtheir bucket full of compost. We have furrows and furrowshijo tienes que ponerle compost, escarbar mas, revolver bien

  20. Las hormigas del Parque Natural de las Sierras de Cazorla, Seguray LasVillas. Labiodiversidadoculta.

    E-Print Network [OSTI]

    Herrera, Carlos M.

    mamíferosy por supuesto, de plantas. Los insectos son otra cuestión. El concepto de Biodiversidad, y aún mas papel vital para el mantenimiento de la biodiversidad y el funcionamiento de los ecosistemas. Estos

  1. Electronic structure analyses and activation studies of a dinitrogen-derived terminal nitride of molybdenum

    E-Print Network [OSTI]

    Sceats, Emma Louise, 1978-

    2004-01-01

    Chapter 1: Complexes obtained by electrophilic attack on a dinitrogen-derived terminal molybdenum nitride: Electronic structure analysis by solid state CP/MAS ¹?N NMR in combination ... Chapter 2. Carbene chemistry in the ...

  2. Protest, voting and political change : the effects of NGOs on politics in developing democracies

    E-Print Network [OSTI]

    Boulding, Carew Elizabeth

    2007-01-01

    political party, headed by Evo Morales.   MBL Movimiento In December of 2005, Evo Morales, the charismatic former the new political  party of Evo Morales, the MAS.   For the 

  3. The politics of representing the past in Bolivia

    E-Print Network [OSTI]

    Kennedy, Edward Fabian

    2009-01-01

    govern the country. But we have the majority! We have Evo.need to support MAS…support Evo. We need the country to knowwiphalas. We need to show Evo that he has campesino support.

  4. The University of Hawai`i does not discriminate on the basis of race, sex, age, color, national origin, or disability. For inquiries regarding our nondiscrimination policies,

    E-Print Network [OSTI]

    Profecionales como Las Artes y Las Comunicaciones, Negocios, Servicios de Salud, La Industria y La Tecnologia de Ingenieria, Recursos Naturals y Sevicios Publicos y Humanos. Para mas informacion, visite nuestra pagina del

  5. Simposio Brasileiro de Arquitetura de Computadores e Processamento de Alto Desempenho

    E-Print Network [OSTI]

    Hexsel, Roberto A

    pro- blema mas introduzem algumas ine ci^encias ine- rentes a seu funcionamento. Por exemplo, quando, hoje e poss vel, em uma unica pastilha, a implementac~ao de processadores com comple- xidade e so

  6. 356 BULLETIN OF THE UNITED ,STATES FISH COMMISSION. the piles of the wharves, shells along the beach and on the beds, aud

    E-Print Network [OSTI]

    to transplant oysters from Prince Edward Island to the Baltic would prow successful ; and I have therefore of the Uanadian Government it mas proved by actual obseryations irrade near Pmince Edward Island, not Far from

  7. Pedro Ponce de León’s Aspiration to Replace Juan de Oñate as the Leader of the Expedition for the Settlement of New Mexico: The Documentary Record

    E-Print Network [OSTI]

    De Marco, Barbara; Craddock, Jerry R

    2015-01-01

    forçoso llebar la mas de aca y ansi suplica que la licenciaynstrucion y cedulas que ansi abeys de guardar en la dichacomo mejor os pareciere ansi para el exem- plo como para el

  8. NOVO CENTRO DE INVESTIGAO NA REA CENTRO DE OCEANOGRAFIA

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    , estuários e zonas costeiras, até ao oceano aberto e mar profundo. Segundo Henrique Cabral, professor com Henrique Cabral, Portugal tem tido notoriedade na investigação ligada ao mar, «mas muitas vezes

  9. American Mineralogist, Volume 89, pages 277284, 2004 0003-004X/04/0203277$05.00 277

    E-Print Network [OSTI]

    Zhang, Youxue

    As the most abundant volatile component in terrestrial mag- mas, dissolved water in silicate glasses and melts al. 1992). However, the kinetics of the reaction has not been investigated and the quench effect has

  10. Essays on multichannel marketing 

    E-Print Network [OSTI]

    Kushwaha, Tarun Lalbahadur

    2009-05-15

    2007 Major Subject: Marketing iii ABSTRACT Essays on Multichannel Marketing. (August 2007) Tarun Lalbahadur Kushwaha, B.Sc., Gujarat University; M.A.S., Nirma University; M.S., Texas A&M University Chair of Advisory Committee: Dr. Venkatesh...

  11. Examen de la Teor'ia de CL1 Junio de 2002 ... con una posible soluci'on

    E-Print Network [OSTI]

    Nieuwenhuis, Robert

    : no conviene hacer estas cosas que se pueden hacer a un nivel previo. ­Variable no­declarada An'alisis sem ambigua la gramatica? ?Por qu'e? S'i es ambigua. Porque existen palabras del lenguaje para las que podemos donde es posible hacer shif t y reduce, elegir'a hacer shif t porque es m'as prioritario POR que MAS. O

  12. THE SOUTHWESTERN NATURALIST 51(1):6470 MARCH 2006 CHARACTERISTICS OF ABERT'S SQUIRREL (SCIURUS ABERTI)

    E-Print Network [OSTI]

    Koprowski, John L.

    - mente en el a´lamo temblo´n (Populus tremuloides) vivo o muerto. Los a´lamos temblones con cavi- dades fueron ma´s grandes que los a´lamos al azar. Sitios con cavidades en a´lamos tuvieron ma´s a´rboles muertos grandes y menos pinos ponderosa y fueron menos empinados que sitios con a´lamos al azar. Las

  13. Departamento de Electromagnetismo y Fisica de la Materia & Institute Carlos I for Theoretical and Computational Physics

    E-Print Network [OSTI]

    Bonachela, Juan Antonio

    , para el autor ´este es a to- das luces el cap´itulo m´as importante de la tesis. Aqu´i, en un humilde trabajo realizado en esta tesis. M´as especialmente, al Departamento de Electromagnetismo y F´isica de la adelante parte de esta tesis, quisiera agradecer su esfuerzo a Ivan Dornic, Hugues Chat´e, Jos´e J. Ramasco

  14. The Condor 106:852861 The Cooper Ornithological Society 2004

    E-Print Network [OSTI]

    Cooper, Sheldon J.

    correlacionan con la preferencia de ha´bitat. La temperatura cri´tica menor de P. gambeli fue 4.2 C ma´s baja. La temperatura cri´tica mayor de P. gambeli fue 4.2 C ma´s baja que la de B. ridgwayi en el verano li´mite superior de temperatura cri´tica, que la de B. ridgwayi, indicando menor tolerancia al calor

  15. Direct multi-wavelength limb-darkening measurements of three late-type giants with the Navy Prototype Optical Interferometer

    E-Print Network [OSTI]

    M. Wittkowski; C. A. Hummel; K. J. Johnston; D. Mozurkewich; A. R. Hajian; N. M. White

    2001-08-10

    We present direct measurements of the limb-darkened intensity profiles of the late-type giant stars HR5299, HR7635, and HR8621 obtained with the Navy Prototype Optical Interferometer (NPOI) at the Lowell Observatory. A triangle of baselines with lengths of 18.9 m, 22.2 m, and 37.5 m was used. We utilized squared visibility amplitudes beyond the first minimum, as well as triple amplitudes and phases in up to 10 spectral channels covering a wavelength range of ~650 nm to ~850 nm. We find that our data can best be described by featureless symmetric limb-darkened disk models while uniform disk and fully darkened disk models can be rejected. We derive high-precision angular limb-darkened diameters for the three stars of 7.44 mas +/- 0.11 mas, 6.18 mas +/- 0.07 mas, and 6.94 mas +/- 0.12 mas, respectively. Using the HIPPARCOS parallaxes, we determine linear limb-darkened radii of 114 R$_\\odot \\pm $13 R$_\\odot$, 56 R$_\\odot \\pm $4 R$_\\odot$, and 98 R$_\\odot \\pm $9 R$_\\odot$, respectively. We compare our data to a grid of Kurucz stellar model atmospheres, with them derive the effective temperatures and surface gravities without additional information, and find agreement with independent estimates derived from empirical calibrations and bolometric fluxes. This confirms the consistency of model predictions and direct observations of the limb-darkening effect.

  16. INTEGRATED CONTROL OF NEXT GENERATION POWER SYSTEM

    SciTech Connect (OSTI)

    2010-02-28

    Control methodologies provide the necessary data acquisition, analysis and corrective actions needed to maintain the state of an electric power system within acceptable operating limits. These methods are primarily software-based algorithms that are nonfunctional unless properly integrated with system data and the appropriate control devices. Components of the control of power systems today include protective relays, supervisory control and data acquisition (SCADA), distribution automation (DA), feeder automation, software agents, sensors, control devices and communications. Necessary corrective actions are still accomplished using large electromechanical devices such as vacuum, oil and gas-insulated breakers, capacitor banks, regulators, transformer tap changers, reclosers, generators, and more recently FACTS (flexible AC transmission system) devices. The recent evolution of multi-agent system (MAS) technologies has been reviewed and effort made to integrate MAS into next generation power systems. A MAS can be defined as ��a loosely-coupled network of problem solvers that work together to solve problems that are beyond their individual capabilities��. These problem solvers, often called agents, are autonomous and may be heterogeneous in nature. This project has shown that a MAS has significant advantages over a single, monolithic, centralized problem solver for next generation power systems. Various communication media are being used in the electric power system today, including copper, optical fiber and power line carrier (PLC) as well as wireless technologies. These technologies have enabled the deployment of substation automation (SA) at many facilities. Recently, carrier and wireless technologies have been developed and demonstrated on a pilot basis. Hence, efforts have been made by this project to penetrate these communication technologies as an infrastructure for next generation power systems. This project has thus pursued efforts to use specific MAS methods as well as pertinent communications protocols to imbed and assess such technologies in a real electric power distribution system, specifically the Circuit of the Future (CoF) developed by Southern California Edison (SCE). By modeling the behavior and communication for the components of a MAS, the operation and control of the power distribution circuit have been enhanced. The use of MAS to model and integrate a power distribution circuit offers a significantly different approach to the design of next generation power systems. For example, ways to control a power distribution circuit that includes a micro-grid while considering the impacts of thermal constraints, and integrating voltage control and renewable energy sources on the main power system have been pursued. Both computer simulations and laboratory testbeds have been used to demonstrate such technologies in electric power distribution systems. An economic assessment of MAS in electric power systems was also performed during this project. A report on the economic feasibility of MAS for electric power systems was prepared, and particularly discusses the feasibility of incorporating MAS in transmission and distribution (T&D) systems. Also, the commercial viability of deploying MAS in T&D systems has been assessed by developing an initial case study using utility input to estimate the benefits of deploying MAS. In summary, the MAS approach, which had previously been investigated with good success by APERC for naval shipboard applications, has now been applied with promising results for enhancing an electric power distribution circuit, such as the Circuit of the Future developed by Southern California Edison. The results for next generation power systems include better ability to reconfigure circuits, improve protection and enhance reliability.

  17. Minor Actinide Recycle in Sodium Cooled Fast Reactors Using Heterogeneous Targets

    SciTech Connect (OSTI)

    Samuel Bays; Pavel Medvedev; Michael Pope; Rodolfo Ferrer; Benoit Forget; Mehdi Asgari

    2009-04-01

    This paper investigates the plausible design of transmutation target assemblies for minor actinides (MA) in Sodium Fast Reactors (SFR). A heterogeneous recycling strategy is investigated, whereby after each reactor pass, un-burned MAs from the targets are blended with MAs produced by the driver fuel and additional MAs from Spent Nuclear Fuel (SNF). A design iteration methodology was adopted for customizing the core design, target assembly design and matrix composition design. The overall design was constrained against allowable peak or maximum in-core performances. While respecting these criteria, the overall design was adjusted to reduce the total number of assemblies fabricated per refueling cycle. It was found that an inert metal-hydride MA-Zr-Hx target matrix gave the highest transmutation efficiency, thus allowing for the least number of targets to be fabricated per reactor cycle.

  18. Investigation of Mechanical Activation on Li-N-H Systems Using 6Li Magic Angle Spinning Nuclear Magnetic Resonance at Ultra-High Field

    SciTech Connect (OSTI)

    Hu, Jian Zhi; Kwak, Ja Hun; Yang, Zhenguo; Osborn, William; Markmaitree, Tippawan; Shaw, Leonard D.

    2008-07-15

    Abstract The significantly enhanced spectral resolution in the 6Li MAS NMR spectra of Li-N-H systems at ultra-high field of 21.1 tesla is exploited, for the first time, to study the detailed electronic and chemical environmental changes associated with mechanical activation of Li-N-H system using high energy balling milling. Complementary to ultra-high field studies, the hydrogen discharge dynamics are investigated using variable temperature in situ 1H MAS NMR at 7.05 tesla field. The significantly enhanced spectral resolution using ultra-high filed of 21.1 tesla was demonstrated along with several major findings related to mechanical activation, including the upfield shift of the resonances in 6Li MAS spectra induced by ball milling, more efficient mechanical activation with ball milling at liquid nitrogen temperature than with ball milling at room temperature, and greatly enhanced hydrogen discharge exhibited by the liquid nitrogen ball milled samples.

  19. SU-E-I-71: KVp Dependence of Transmitted Exposure for a Radiography Unit

    SciTech Connect (OSTI)

    Liang, Y; Lynch, D; So, J; Dutta, A

    2014-06-01

    Purpose: To investigate the kVp dependence of the transmitted exposure for a radiography x-ray unit. Methods: The study used a GE DiscoveryTM XR656 DR unit, a 30 (L) × 30 (W) × 25 cm thick Lucite phantom, two anthropomorphic phantoms (an Alderson RS-310 chest phantom and a 3M skull phantom), an Unfors detector, and a Radcal 10x9-6 ion chamber. We measured the entrance exposure and transmitted exposure of each phantom at 60, 70, 80, 90, 100, 110, 120 kVp for mAs range from 2.5 to 200 mAs, without any additional filter. The FOV is 30×30 cm for the Lucite and chest phantom (AP view), and 20×20 cm for skull phantom (Lateral view). The transmitted exposure was measured at the phantom center of the x-ray exit side. For chest phantom, the transmitted exposures at 3 inch upper right and upper left from the center were also measured. We also checked the reproducibility and accuracy of the DR unit. Results: For each phantom, at every kVp and mAs setting, the transmitted exposure per mAs was calculated and normalized by the relative entrance exposure; the averaged transmitted exposure per mAs at each specific kVp was then determined. For chest phantom, the mean transmitted exposure per mAs was the average of three exit locations. The averaged transmitted exposure per mAs was fit as a power function of kVp. The result showed the transmitted exposure per mAs was approximately proportional to third power of the kVp for two anthropomorphic phantoms and forth power of the kVp for the Lucite phantom. Conclusion: The traditional assumption of fifth power kVp dependence to the transmitted exposure is inaccurate. At the normal radiography kVp range, the transmitted exposure is approximately proportional to third power of the kVp for a typical patient and up to forth power of the kVp for a large patient.

  20. Solid-state NMR studies of the adsorption of acetylene on platinum/alumina catalysts 

    E-Print Network [OSTI]

    Lambregts, Marsha Jo Lupher

    1991-01-01

    /y-alumina and subsequently evacuated. 25 "C Bloch Decay/MAS NMR spectra of cyclohexane adsorbed onto 10%Pt/y-alumina. 27 FT mass spectra taken at a field strength of 3-Tesla. 28 CAVERN uC CP/MAS NMR spectra of an overpressure of acetylene on 10%Pt/y-alumina adsorbed... pumped two-section ion cell, an Extrel 2001 data system, and a 3-Tesla Oxford superconducting magnet. ~~ Samples were introduced into the cell by a variable leak valve (at sample pressure of 4 x 10' torr). Ionization was performed by electron impact...

  1. Tridentate Phosphine Linkers for Immobilized Catalysts: Development and Characterization of Immobilized Rhodium Complexes and Solid-State NMR Studies of Polymers 

    E-Print Network [OSTI]

    Guenther, Johannes 1983-

    2012-08-16

    ) and 45 (bottom, 4.5 kHz spinning speed). ............................................................................ 141 4.5 29Si CP/MAS spectra of 44 (top, 0 kHz spinning speed; middle: 1.5 kHz spinning speed; bottom, 10 kHz spinning speed...). ...................................... 142 4.6 29Si CP/MAS spectra of 44 (top, 1.5 kHz spinning speed) and 45 (bottom, 5 kHz spinning speed). ................................................................ 143 4.7 31P NMR spectrum of 47 in CDCl3...

  2. Multinuclear Solid-State NMR Studies of Polymers and Immobilized Sonogashira Catalysts for Cross-Coupling Reactions 

    E-Print Network [OSTI]

    Pope, Jacqueline Christine

    2014-08-28

    azabisisobutyronitrile BET Brunauer Emmett Teller br broad Bu butyl COSY COrrelation SpectroscopY (2D NMR) CP cross-polarization CP/MAS cross-polarization/magic angle spinning CSA chemical shift anisotropy Cy cyclohexyl d doublet (NMR), days viii... ................................................................................................................. 284 xii LIST OF FIGURES FIGURE Page 2.1. 13C CP/MAS NMR spectra of PBI (a), PEEK (b), melt-blended PEEK- PBI (c), and a physical mixture of powdered PEEK and PBI (50:50 wt%) (d). The spinning speed is 10 kHz for all spectra...

  3. Ring shaped 6.7 GHz methanol maser emission around a young high-mass star

    E-Print Network [OSTI]

    A. Bartkiewicz; M. Szymczak; H. J. van Langevelde

    2005-09-21

    We report on EVN imaging of the 6.7 GHz methanol maser emission from the candidate high-mass protostar G23.657-0.127. The masers originate in a nearly circular ring of 127 mas radius and 12 mas width. The ring structure points at a central exciting object which characteristics are typical for a young massive star; its bolometric luminosity is estimated to be methanol masers originate in a spherical bubble or in a rotating disc seen nearly face-on.

  4. Determination of the Average Aromatic Cluster Size of Fossil Fuels by Solid-State NMR at High Magnetic Field

    SciTech Connect (OSTI)

    Mao, Kanmi; Kennedy, Gordon J.; Althaus, Stacey M.; Pruski, Marek

    2013-01-07

    We show that the average aromatic cluster size in complex carbonaceous materials can be accurately determined using fast magic-angle spinning (MAS) NMR at a high magnetic field. To accurately quantify the nonprotonated aromatic carbon, we edited the 13C spectra using the recently reported MAS-synchronized spin–echo, which alleviated the problem of rotational recoupling of 1H-13C dipolar interactions associated with traditional dipolar dephasing experiments. The dependability of this approach was demonstrated on selected Argonne Premium coal standards, for which full sets of basic structural parameters were determined with high accuracy.

  5. Revista Iguanazul, Number 3

    E-Print Network [OSTI]

    Santopietro, Judith

    "'LO (V .. racrul. Verilcnlz) t."Mi~l'la C.ubajal {Xalap~, VeracruotJ Corrtspons~ I .. ~ en "lell lra!tluo Juan Car/os Mieses (SAo Paulo, 8r,,~m Estelle J"'I;.· .. ' (Renne, Franct .. ) JCUANAZUL", una pul>lkildl'>n ItimKlral, su Hra", e..J~ mil ~Jemr... Jencia innecesaria del destino? Quien sabe cua:ndo, el h~ho es que un dia descubri6 que habia perdido la fe". Tal vez Ln noche de /(Is/lOnnigas sea la mejor obra de Pettersson, la mas pulidaen el estilo, la mas poetica, la que sintetiza y da cuenta de su...

  6. Chapter 3--Lahar Deposits Lahar Deposits

    E-Print Network [OSTI]

    del Moral, Roger

    with snow and ice, the rapid melting causes lahars that flow down canyons. Slurries entrain soil, rocks above the deposit (July 1980). 27 #12;Chapter 3--Lahar Deposits out. Glaciers and snow fields melt rapidly and small block- ing dams (often glacial moraines) collapse to produce mas- sive surges

  7. Caribbean Journal of Science, Vol. 33, No. 34, 191197, 1997 Copyright 1997 College of Arts and Sciences

    E-Print Network [OSTI]

    Hazen, Terry

    lugar pristino y en un lugar expuesto a contaminacio´n de aguas residuales en la cuenca de un ri´o en ambientes tropicales de agua dulce enfatizan au´n ma´s la importancia del tratamiento adecuado de aguas residuales y la necesidad de mejores me´todos para monitorear bacterias indicadoras de contaminacio´n fecal

  8. Economia y finanzas matematicas Cuarto curso, licenciatura en Matematicas, UAM, 2011-2012

    E-Print Network [OSTI]

    Fernández Gallardo, Pablo

    tipo de inter´es continuo es R. ¿Cu´al de las dos costar´a m´as (hoy)? 3. (2 puntos) Considera el siguiente modelo matricial: precios hoy 0.9 0 3 flujos en t = 1 1 1 1 1 0 -1 1 x 0 1 2 3 S1 S2 S3 tipo

  9. Estudio de dos ecuaciones parabolicas lineales con metodos de energia

    E-Print Network [OSTI]

    Granero, Rafael

    energ´ia. Daremos un ap´endice con los resultados m´as ´utiles en este tipo de c´alculos. Palabras clave sustancia y supongamos cierta la Ley de Fourier (que afirma que el flujo es proporcional al gradiente

  10. Modelling of macroscopic magnetic islands in tokamaks F. Porcellia,b

    E-Print Network [OSTI]

    Rossi, Enrico

    Modelling of macroscopic magnetic islands in tokamaks F. Porcellia,b , A. Airoldic , C. Angionid of saw- teeth and neoclassical tearing modes in tokamak plasmas. The main findings the confinement properties of tokamak plas- mas are limited by the onset of macroscopic, coher- ent magnetic

  11. 1) O que o Inpe faz? O Instituto Nacional de Pesquisas Espaciais (INPE) foi criado em 1961 com o objetivo

    E-Print Network [OSTI]

    espacial, meteorologia, observação da Terra por imagens de satélite e estudos de mudanças climáticas. 2-graduação nas áreas de Astrofísica, Geofísica Espacial, Computação Aplicada, Meteorologia, Sensoriamento Remoto meteorologia e ciências ligadas ao meio ambiente), mas não é uma agência. No Brasil, existe a Agência Espacial

  12. Climatic and tectonic implications of the late Miocene Jakokkota ora, Bolivian Altiplano

    E-Print Network [OSTI]

    Gregory-Wodzicki, Kathryn M.

    of Columbia University, Palisades, NY 10964-8000, USA 2 New Mexico Bureau of Mines and Mineral Resources ®siognomõÂa moderna y el clima. Similarmente, una muestra derivada de la literatura de la ¯ora Potosõ 50240 cm. Entonces, par- ece que el paleoclima era mas caliente que el clima actual de terreno montan

  13. ANTHROPOLOGY HISTORY AND MEMORY Anthropology Professors

    E-Print Network [OSTI]

    Watkins, Joseph C.

    ANTHROPOLOGY HISTORY AND MEMORY Anthropology Professors Ana Alonzo Maribel Alvarez TJ Ferguson of the Southwest ANTH 417A (MENAS) North African Societies: History, Culture and Politics ANTH 418 Southwest Land, Culture and History ANTH 475A (MAS) The Education of Latinas/Latinos Click here to search for course

  14. Scribere Est Agere ou O Direito ao Grito: O Intelectual Oprimido e a Hora do Subalterno em A Hora da Estrela

    E-Print Network [OSTI]

    Tosta, Antonio L.

    2009-01-05

    oratória, mas isso não lhe garante que sua obra tenha o impacto social ou educacional que gostaria. Através de Rodrigo S. M. Lispector encena seu dilema de consciência enquanto escritora e intelectual burguesa. Primeiro o narrador tenta aproximar-se da...

  15. 304 IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING, VOL. 4, NO. 4, NOVEMBER 1991 A Process Control Methodology Applied to

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    by the Leaders for Manufacturing Program at the Mas- sachusetts Institute of Technology (MIT). Leaders for Manufacturing is a partnership between the MIT School of Engineering. the MIT Sloan School of Management304 IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING, VOL. 4, NO. 4, NOVEMBER 1991 A Process

  16. A periphery of Pogamut: from bots to agents and back Jakub Gemrot, Cyril Brom, Toms Plch

    E-Print Network [OSTI]

    Brom, Cyril

    . This paper also reviews Pogamut, which the researcher can utilise. Keywords. videogames, agents, action (AI) for videogames seems to have caught second wind [1]. Results achieved in disciplines and approaches to known problems. Can knowledge accumulated by the multi-agent systems (MAS) community during

  17. F. Dignum (Ed.): Agents for Games and Simulations II, LNAI 6525, pp. 1937, 2011. Springer-Verlag Berlin Heidelberg 2011

    E-Print Network [OSTI]

    Brom, Cyril

    . This paper also reviews Pogamut, which the researcher can utilise. Keywords: videogames, agents, action (AI) for videogames seems to have caught second wind [1]. Results achieved in disciplines and approaches to known problems. Can knowledge accumulated by the multi-agent systems (MAS) community during

  18. RELACIN ENTRE NDVI Y CONTENIDO DE METALES EN RHIZOPHORA MANGLE EN EL SUROESTE DE PUERTO RICO

    E-Print Network [OSTI]

    Gilbes, Fernando

    Mangles Los mangles se encuentran en áreas bañadas de agua, suelos salados y costas distancia desde la orilla del mar hacia es el que habita en la zona inundada por el agua por su estabilidad por encontrarse en al área mas directamente afectado por la energía del agua. Estas

  19. 260 BULLETIS OF THE VNITED STATES FISH COMIMISSTOX. certain share of the total gield, generally $0 to $10 per thonsaud fish.

    E-Print Network [OSTI]

    POND FOR REARING S T R I P E D BA08 (HOCCUB XJNE. ATUS) I N DELAWARE BAY. B y E. R e NOEENY. [From- count of its color. The lower part, or tail part, mas a shiny black wlien alive, shading to a dull blackjustified in making the appropriation of about $250 to complete the pond I wrote aljout a year ago

  20. A deep proper motion catalog within the Sloan digital sky survey footprint

    SciTech Connect (OSTI)

    Munn, Jeffrey A.; Harris, Hugh C.; Tilleman, Trudy M. [US Naval Observatory, Flagstaff Station, 10391 West Naval Observatory Road, Flagstaff, AZ 86005-8521 (United States); Hippel, Ted von [Embry-Riddle Aeronautical University, Physical Sciences, 600 South Clyde Morris Boulevard Daytona Beach, FL 32114-3900 (United States); Kilic, Mukremin [University of Oklahoma, Homer L. Dodge Department of Physics and Astronomy, 440 West Brooks Street, Norman, OK 73019 (United States); Liebert, James W. [University of Arizona, Steward Observatory, Tucson, AZ 85721 (United States); Williams, Kurtis A. [Department of Physics and Astronomy, Texas A and M University-Commerce, P.O. Box 3011, Commerce, TX 75429 (United States); DeGenarro, Steven [Department of Astronomy, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States); Jeffery, Elizabeth, E-mail: jam@nofs.navy.mil, E-mail: hch@nofs.navy.mil, E-mail: trudy@nofs.navy.mil, E-mail: ted.vonhippel@erau.edu, E-mail: kilic@ou.edu, E-mail: jamesliebert@gmail.com, E-mail: kurtis.williams@tamuc.edu, E-mail: studiofortytwo@yahoo.com, E-mail: ejeffery@byu.edu [BYU Department of Physics and Astronomy, N283 ESC, Provo, UT 84602 (United States)

    2014-12-01

    A new proper motion catalog is presented, combining the Sloan Digital Sky Survey (SDSS) with second epoch observations in the r band within a portion of the SDSS imaging footprint. The new observations were obtained with the 90prime camera on the Steward Observatory Bok 90 inch telescope, and the Array Camera on the U.S. Naval Observatory, Flagstaff Station, 1.3 m telescope. The catalog covers 1098 square degrees to r = 22.0, an additional 1521 square degrees to r = 20.9, plus a further 488 square degrees of lesser quality data. Statistical errors in the proper motions range from 5 mas year{sup ?1} at the bright end to 15 mas year{sup ?1} at the faint end, for a typical epoch difference of six years. Systematic errors are estimated to be roughly 1 mas year{sup ?1} for the Array Camera data, and as much as 2–4 mas year{sup ?1} for the 90prime data (though typically less). The catalog also includes a second epoch of r band photometry.

  1. Distributed Runtime Verification of JADE Multiagent Systems

    E-Print Network [OSTI]

    Mascardi, Viviana

    to a given global protocol is of paramount importance for most systems, and is mandatory for safety-critical of the verification activities. Reducing the log files dimension, re-implementing the monitor in a way independent in the JADE Homepage. FYPA (Find Your Path, Agent! [6, 7, 8]) is another industrial MAS developed in JADE

  2. Modelling regulations Completing an incomplete regulation

    E-Print Network [OSTI]

    van der Torre, Leon

    Objectives Modelling regulations Completing an incomplete regulation Examples Discussion Consistency and Completeness of Regulations Laurence Cholvy1 St´ephanie Roussel1,2 1ONERA Centre de Toulouse 2ISAE, Toulouse NorMAS 2008, Luxembourg, July 2008 cholvy Consistency and Completeness of Regulations

  3. Laboratorio 2: Analisis de datos bivariantes Tablas de Contingencia, Diagramas de Barras

    E-Print Network [OSTI]

    Gil, Ana Arribas

    instrucciones, cargar la librer´ia lattice y realizar un diagrama de barras m´as cool: library(lattice) barchart desde paquete adjunto... En la ventana de di´alogo, en el panel derecho, elegir el paquete datasets (haciendo click dos veces). Buscar a lo largo del panel derecho hasta encontrar anscombe y seleccio- narlo

  4. A Study of Grouping Effect On Mobile Actuator Sensor Networks for Distributed Feedback Control of Diffusion Process Using Central Voronoi Tessellations

    E-Print Network [OSTI]

    Ren, Wei

    grouping, mobile actuator networks, coordinated control, diffusion process, pollution neutralization, Centroidal Voronoi Tessellation. I. INTRODUCTION The deployment of large groups of unmanned vehicles for pollution detection which mo- tivates "Mobile Actuator and Sensor Network (MAS-net) project" in CSOIS, Utah

  5. Climatology of Large Sediment Resuspension Events in Southern Lake Michigan

    E-Print Network [OSTI]

    Climatology of Large Sediment Resuspension Events in Southern Lake Michigan David J. Schwab1 the southern basin, is subject to recurrent episodes of mas- sive sediment resuspension by storm-induced waves with the largest events are examined. Our analysis indicates that significant resuspension events in southern Lake

  6. Avaliao de Mtodos de Interpolao do Sinal de Variabilidade da Freqncia Cardaca

    E-Print Network [OSTI]

    Carvalho, João Luiz

    métodos de interpolação do sinal de variabilidade da freqüência cardíaca, ou heart rate variability (HRV). O sinal de HRV é usado como uma ferramenta para a avaliação da atuação do sistema nervoso para a análise espectral do sinal de HRV, mas estes exigem que o sinal tenha sido amostrado com taxa de

  7. IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 59, NO. 10, OCTOBER 2012 2667 Strain and Temperature Dependence of Defect

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    -Han Lin, Student Member, IEEE, Tyler A. Merz, Daniel R. Doutt, Jungwoo Joh, Jesús A. del Alamo, Fellow. del Alamo is with the Microsystems Technology Laboratories, Mas- sachusetts Institute of Technology, Cambridge, MA, 02139 USA (email: alamo@mit.edu). U. K. Mishra is with the Department of Electrical

  8. Automation of Termination: Abstracting CCG through MWG Automation of Termination: Abstracting Calling

    E-Print Network [OSTI]

    Ayala-Rincón, Mauricio

    Automation of Termination: Abstracting CCG through MWG Automation of Termination: Abstracting.Ayala-Rinc´on & C.A.Munoz IX Semin´ario Informal(, mas Formal!) November 29, 2013 1 / 32 #12;Automation science. While classical results state the undecidability of various termination problems, automated

  9. Fish Fingers and Custard Issue 4 

    E-Print Network [OSTI]

    2011-01-01

    ? Tenne at?i the United States between 1'949 and 1955. hitter? Clay J, ? FedoraXMtate Marhet Weve Ssrv ce? t City, crida? 56, yi2, Q US04? 4gricu1tural Marheting Ssrvtss? ni. ~ot?y, 120. TABID 1 VAIUE OF MA'P'hFKLOH OUOPS IN HQ". KA~ KCF. GIA~ ~M;AS J...

  10. JOB SUMMARY JOB TITLE: RESEARCH FELLOW (Multi-Agent Systems for Large-Scale Evolving SCADA (Research Fellows

    E-Print Network [OSTI]

    Liu, Weiru

    JOB SUMMARY JOB TITLE: RESEARCH FELLOW (Multi-Agent Systems for Large-Scale Evolving SCADA, the research topics include: (i) developing multi-agent system architecture for supporting SCADA systems-agent environments and integrating planning knowledge; (iii) investigating security vulnerabilities in MAS for SCADA

  11. 2566 IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 55, NO. 5, OCTOBER 2008 Virtual Colonoscopy Screening With Ultra Low-Dose

    E-Print Network [OSTI]

    with normal dose scans at 100 mAs levels. The simulated noisy sinogram or projection data were first processed by a Karhunen-Loève domain penalized weighted least-squares (KL-PWLS) restoration method and then reconstructed lumen was constructed and navigated by a VC system after electronic colon cleansing of the orally

  12. IOP PUBLISHING PHYSICS IN MEDICINE AND BIOLOGY Phys. Med. Biol. 53 (2008) 28972909 doi:10.1088/0031-9155/53/11/009

    E-Print Network [OSTI]

    2008-01-01

    properties of the sinogram, a penalized weighted least-squares (PWLS) objective function was constructed doses to patients. One way to reduce the patient dose is to lower mAs when acquiring projection data information in the projection data, an anisotropic penalty term was designed using the intensity difference

  13. Institutions and Cross-border Mergers and Acquisitions (M&A) Value Creation 

    E-Print Network [OSTI]

    Zhu, Hong

    2012-02-14

    little effect on cross-border M&A value creation. We therefore still do not understand the processes behind cross-border M&As. In this is dissertation I examine the main effects of host country regulatory, economic and physical infrastructure...

  14. Sensores CMOS para robotica e industria: Sensor ret nico espacio variante y vision activa

    E-Print Network [OSTI]

    Valencia, Universidad de

    imagenes con tecnolog a CMOS, son to- dav a conceptos poco conocidos en entornos industriales. En este art percepcion visiva, asemejandose cada vez mas a sus creadores. Por otro lado se presenta la tecnolog a CMOS. Por ultimo, se fun- den ambos conceptos y se presenta un sensor de imagenes, basado en tecnolog a CMOS

  15. Functional Compression through Graph Coloring Vishal Doshi, Student Member, IEEE, Devavrat Shah, Member, IEEE, Muriel Medard, Fellow, IEEE,

    E-Print Network [OSTI]

    information from disparate sources to a third party. The key contributions of this article are to provide for Information and Decision Systems, Massachusetts Institute of Technology. D. Shah is with Laboratory for Information and Decision Systems, department of EECS, Mas- sachusetts Institute of Technology. M. M

  16. Version: 2009 January 15 The distance to a star forming region in the Outer arm of the

    E-Print Network [OSTI]

    Brunthaler, Andreas

    Version: 2009 January 15 The distance to a star forming region in the Outer arm of the Galaxy K spiral arm of the Galaxy. We measure an annual parallax of 0.167±0.006 mas, corresponding the presence of a faint Outer arm toward l = 135 # . We also measured the full space motion of the object

  17. Matematica Discreta Asignatura optativa de la Licenciatura de Matematicas (UAM)

    E-Print Network [OSTI]

    Quirós, Fernando

    ) 6 2. Demu´estrese que en todo grafo conexo con m´as de dos v´ertices tiene que haber al menos dos v palo- mares los grados. 3. Demu´estrese que los dos siguientes grafos son isomorfos. ¿Cu tiene al menos k - 1 v´ertices. 7. Siete estudiantes se van de vacaciones y deciden que cada uno

  18. Gomez Villegas, M. A. (2014). 2013, A~no internacional de la estadistica: una panoramica. Historia de la Probabilidad y la Estadistica [VII] (J. Santos y S. de Paz, eds.), Madrid: Delta, 1129.

    E-Print Network [OSTI]

    Gómez Villegas, Miguel Ángel

    2014-01-01

    ´amica. Historia de la Probabilidad y la Estad´istica [VII] (J. Santos y S. de Paz, eds.), Madrid: Delta, 11) Universidad Complutense de Madrid 1. Introducci´on En este trabajo se recoge una panor´amica de la historia de dos ciudades, Padua, dependiente del Senado de Florencia, m´as abierta, y Pisa dependiente de la

  19. Simple Adaptive Strategies: From Regret Matching

    E-Print Network [OSTI]

    Hart, Sergiu

    Simple Adaptive Strategies: From Regret Matching to Uncoupled Dynamics Sergiu Hart Andreu Mas, computers--even genes. See the Hand- book of Game Theory (Aumann and Hart 1994, 2002, 2004; Young and Zamir, Israel. E-mail: hart@huji.ac.il; URL: http://www.ma.huji.ac.il/hart. Department of Economics

  20. Informacion Cuantica y Sistemas Colectivos

    E-Print Network [OSTI]

    Informaci´on Cu´antica y Sistemas Colectivos Carlos Enrique L´opez Cabrera Tesis presentada para´opez Cabrera Tesis enviada para obtener el grado de Doctor en Ciencias con menci´on en F´isica USACH, Santiago esta tesis se estudian algunos de estos sistemas f´isicos compuestos de una y m´as part´iculas. Este

  1. UNIVERSIDAD DE CHILE FACULTAD DE CIENCIAS F ' ISICAS Y MATEM '

    E-Print Network [OSTI]

    Hevia, Alejandro

    'on y almacenamiento de la informaci'on. Ejemplos de ellos son la privacidad (confidencialidad del'on de la criptograf'ia se ha extendido vertiginosamente en las ' ulti­ mas dos d'ecadas. Por ejemplo a Shang--Hua Teng, por su oportuno consejo acerca del tema de esta tesis, a Marcos Kiwi, por su invaluable

  2. Seguridad y Configuracion de Redes de Computadoras con GNU/Linux

    E-Print Network [OSTI]

    Fraga, Luis Gerardo de la

    nuestros estu- diantes est´an trabajando en sus tesis con redes y servicios experimentales, tal como IPv6 de la Secci´on, por ejemplo, funcionan desde ha- ce m´as de cuatro a~nos con GNU/Linux. 2 Seguridad. Historicamente se han tenido los siguientes problemas. Los estudiantes en su trabajo de tesis se les asigna una

  3. Cohomologia cuantica tangencial y numeros caracteristicos Joachim Kock

    E-Print Network [OSTI]

    Kock, Joachim

    explicativa de la tesis es una traducci´on de una memoria publicada en los Anais da Academia Brasileira de Ci^encias, 73 (2001), 319­326. Ulteriormente, mas tres publicaciones resultaron de la tesis: · T. Graber, J´enea) sujeta a condiciones de naturaleza infinitesimal, como por ejemplo tangencia. El concepto clave es lo de

  4. Pgina Inicial Empresas Start-ups portuguesas mostram-se hoje a investidores suecos em Lisboa Empresas criadas em

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    Energia Internacional O Governo quer cortar os salários também nas empresas públicas. Mas ao contrário do ano... LEIA TUDO Últimas Telecom Construção Energia Internacional | Empresas criadas em PortugalPágina Inicial Empresas Start-ups portuguesas mostram-se hoje a investidores suecos em Lisboa

  5. Expresso Online Pas: Portugal

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    direito de a escrever Governo: Miguel Relvas garante que claro que confia em Paulo ... Crédito às empresas energia do buraco negro muito rapidamente Comente Uma equipa internacional liderada por dois cientistas do supostamente formam a matéria e a energia escuras, que ainda não são conhecidas mas constituem 96% do Universo

  6. XXV Curso de Introduccin a la Investigacin en ptica -Ao Internacional de la Luz 2015 Este curso proporciona una introduccin terico-prctica de los campos de investigacin de la ptica moderna de los Grupos

    E-Print Network [OSTI]

    XXV Curso de Introducción a la Investigación en Óptica - Año Internacional de la Luz 2015 Este ellos a proyectos de investigación en curso. Con motivo del Año Internacional de la Luz 2015 (UNESCO) se añadirán contenidos adicionales de carácter mas divulgativo y de concienciación de la importancia de la luz

  7. 38 CINCIA HOJE vol. 30 n 177 A S T R O N O M I A

    E-Print Network [OSTI]

    Barcelona, Universitat de

    em horas de luz e de trevas. A órbita da Terra em torno do Sol configura a duração temporal de luz e calor para a vida na Terra, mas a quantidade e a qualidade da luz e do calor Figura 1

  8. || 23.04.2015Focus specialization at IVP 1 Focus: Manufacturing Science -IVP

    E-Print Network [OSTI]

    Daraio, Chiara

    ;|| Automotive industry Food & pharmaceutical packaging Electronics assembly Components of household http://www.ivp.ethz.chhttp://www.iwf.mavt.ethz.ch #12;|| Industrial application fields of forming Bachelor thesis MaS Industrial Internships 23.04.2015Focus specialization at IVP 2 Content #12

  9. Fundao para a Cincia com

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    dinheiro para bolsas e projectos de investigação EDUARDO MARTINS Orçamento. Fundação para a Ciência com desenvolvimento de uma economia baseada no conheci- mento e de alto valor acrescen- tado". Mas de acordo com o Ciência e Tecnologia: bolsas, projectos, instituições, cooperação internacional - vai mesmo sofrer uma

  10. Ricardo Oliveira Duarte Storyteller_PT Email BURACOS NEGROS ESPAO FSICA INSTITUTO SUPERIOR TCNICO

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    bolsa do mesmo ERC, mas no valor de um milhão de euros. "Deu para muita coisa. Instituiu em Portugal o TÉCNICO Autor Tópicos FÍSICA Investigador português ganha bolsa de um milhão e meio de euros 26/1/2015, 21 português ganha bolsa de um milhão e meio de euros - Obs... http://observador.pt/2015/01/26/investigador-portugues-ganha-bolsa

  11. Mais de dois mil alunos desistiram

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    difícil de avaliar PATRÍCIA JESUS Sem direito a bolsa, com propinas e residên- cia para pagar, o os de licenciatura e mestrado, um valor acumulado de mais de um milhão e trezentos mil euros. "Mesmo propinas e residência, devido a mau aproveitamento. Mas tem colegas sem #12;direito a bolsa e que não

  12. plurianuais universidades

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    forma que reclamam "uma adequada política de atribuição de bolsas", por en- tenderem que a atual lei redução de custos, mas sim como pro- cesso de criação de valor." Após este primeiro encon- tro ficou REIVINDI- CAM NOVA POLÍ- TICA DE ATRIBUI- ÇÃO DE BOLSAS #12;

  13. Asociaciones Trasformacion de codons a aminoacidos

    E-Print Network [OSTI]

    Giménez, Domingo

    repetidos se habla de bolsas. Las operaciones m´as frecuentes entre conjuntos son: Uni´on, Intersecci distintos podemos formar con ellos? Representamos uno de estos conjuntos con cuatro valores 0 o 1, con 0 puede acceder al valor asociado a una clave: $definition = $english dictionary{'recreant'} o asociar un

  14. Eng Chemistry 1 (3) Logic Design (4)

    E-Print Network [OSTI]

    Fernandez, Eduardo

    Eng Chemistry 1 (3) EGN 2095 Logic Design (4) CDA 3201C Fundamentals of Engineering (3) EGN 1002 Engineering Design 2 (3) EGN 4411C Electromagnetic Fields & Waves (4) EEL 3470 Calculus for Eng 1 (4) MAC 2281) Examples of Upper Division Math Electives: MAS 2103 Matrix Theory (only exception) MAP 4306 Engineering

  15. Marine EM Reference Database http://marineemlab.ucsd.edu/~kkey/MarineEM

    E-Print Network [OSTI]

    Key, Kerry

    for mapping seafloor electrical conductivity. The database also includes student PhD and Mas- ters theses Workshop, held in Giza Egypt during September 2010. The review paper is now available online: Key, K. (2011] Wertheim, G., 1953. Studies of the electric potential between Key West, Florida, and Havana, Cuba

  16. Marine EM Reference Database http://marineemlab.ucsd.edu/~kkey/MarineEM

    E-Print Network [OSTI]

    Key, Kerry

    for mapping seafloor electrical conductivity. The database also includes student PhD and Mas- ters theses Workshop, held in Giza Egypt during September 2010. The review paper is now available online: Key, K. (2011, Electrical structure beneath the northern MELT line on the East Pacific Rise at 15 degrees 45 ' S

  17. BIS Beckman Institute Seminar BL Beckman Lecture

    E-Print Network [OSTI]

    Stoltz, Brian M.

    -Myers Squibb Lectures in Organic Synthesis BS Biochemistry Seminar CBC Caltech Biotech Club CCS Chemistry Club IN CHEMISTRY AND CHEMICAL ENGINEERING June 12, 2009 IES Inorganic-Electrochemistry Seminar IOS Inorganic Lectureship MAS McCoy Award Seminar MRL Materials Research Lecture (CCE co-sponsor) NDL Norman Davidson

  18. Boletin de la Sociedad de Estadistica e Investigacion Operativa (2011), 27, 1, 85-87.

    E-Print Network [OSTI]

    Gómez Villegas, Miguel Ángel

    2011-01-01

    y creci´o en Centralia, en Illinois, asistiendo a una escuela sin segregaci´on racial, fuera de la Academy of Arts and Sciences y encargado de impartir las m´as prestigiosas conferencias. Presidi´o el Ciencias F´isicas y la Sociedad Bernoulli, recibi´o 12 doctorados honor´ificos y public´o 80 art

  19. Falta de investimento prejudica sector em Portugal

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    .car*alF»o@ecOnomlco.pt Portugal tem condições para se tornar um exemplo de sucesso no desenvolvimento da biotecnologia, mas ainda- estruturas físicas e o "investi- mento descontinuado" - a biotecnologia re- quer investimento de longo prazo, "falta verdadeiro capital de risco investidor em ciências da vida em ge- ral, e em biotecnologia em

  20. INTERNET 2 : Las nuevas redes del futuro Juan Manuel Torres Moreno

    E-Print Network [OSTI]

    Avignon et des Pays de Vaucluse, Université de

    INTERNET 2 : Las nuevas redes del futuro Juan Manuel Torres Moreno Laboratorio Nacional de más virtual) pero aún mas impactante: la revolución de las redes de computadoras. Internet ha supuesto vistas. Internet constituye al mismo tiempo un mecanismo de difusión mundial, de propagación, interacción

  1. A. A. (TONY) EKDALE ACADEMIC POSITION

    E-Print Network [OSTI]

    Johnson, Cari

    .C., & Ekdale, A.A., 2014, Ichnology and sedimentology of an Eocene greensand in Texas: behavioral response: Developments in Sedimentology 64, Elsevier, Amsterdam, p. 139-155. Ekdale, A.A., & Bromley, R.G., 2012, Eolian: Developments in Sedimentology 64, Elsevier, Amsterdam, p. 419-437. Gibert, J.M. de, Mas, G., & Ekdale, A

  2. Metodos combinatorios en teoria de juegos Introduccion

    E-Print Network [OSTI]

    Bilbao Arrese, Jesús Mario

    potencial de Hart y Mas-Colell. En el ret´iculo (L, ), el intervalo [S-, S] es un ´algebra de Boole para´ia convexa de partici´on, el intervalo [T, T+] es un ´algebra de Boole, para T L, T 6= , si

  3. ccsd00001714, Nonlinear dynamics of electromagnetic pulses in cold relativistic plasmas

    E-Print Network [OSTI]

    ccsd­00001714, version 2 ­ 19 Oct 2004 Nonlinear dynamics of electromagnetic pulses in cold. In the present analysis we study the self consistent propagation of nonlinear electromagnetic pulses in a one. INTRODUCTION Propagation of intense electromagnetic pulses in plas- mas is a subject of current interest

  4. ccsd-00001714,version2-19Oct2004 Nonlinear dynamics of electromagnetic pulses in cold relativistic plasmas

    E-Print Network [OSTI]

    Boyer, Edmond

    ccsd-00001714,version2-19Oct2004 Nonlinear dynamics of electromagnetic pulses in cold relativistic analysis we study the self consistent propagation of nonlinear electromagnetic pulses in a one dimensional. INTRODUCTION Propagation of intense electromagnetic pulses in plas- mas is a subject of current interest

  5. Germ'an Vidal Oriola Doctor en Inform'atica

    E-Print Network [OSTI]

    Vidal, Germán

    la integraci'on de la programaci'on l'ogica y funcional est'a considera­ do como uno de los m'as importantes en el 'area de investigaci'on sobre programaci'on declarativa. Para que los lenguajes declarativos

  6. Bayerischer Landtag 16. Wahlperiode Drucksache 16/6696

    E-Print Network [OSTI]

    Pukelsheim, Friedrich

    Sicherheit 1. Gesetzentwurf der Abgeordneten Thomas Hacker, Dr. Andreas Fischer, Tobias Thalhammer u.a. und- gesetzes 2. Änderungsantrag der Abgeordneten Tho- mas Hacker, Dr. Andreas Fischer, Jörg Rohde u.a. FDP, Christian Meißner u.a. CSU Drs. 16/5202 zum Gesetzentwurf der Abgeordneten Hacker, Dr. Fischer, Thalhammer u

  7. Tiragem: 22956 Pas: Portugal

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    profissionais de Ciência e Tecnologia (C&T) que há nas empre- sas da região flamenca. "Só para engenheiros há cerca de três mil va- gas, mas, se juntarmos os profissionais do sec- tordaCiênciaeTecnologia vagas no sector das engenharias e tecnologias, a Bélgica decidiu começar a contratar em países onde há

  8. ARTIGO INTERNET Prmio Jaime Filipe atribudo a investigador do IST

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    Tecnologias de Apoio, inserida na comunidade de spin-offs do IST. O projecto vencedor, Palmiber, tem como portadoras de disfunções neuromotoras graves e/ou outros deficits sensoriais e cognitivos. É uma tecnologia tecnologias médicas. O projecto integra "conhecimentos científicos diversos mas complementares". O Prémio

  9. Tiragem: 13100 Pas: Portugal

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    outros meios académicos". "O setor público devia ser o motor da introdução das novas tecnologias e da modernização" Questionado sobre qual o fu- turo da tecnologia e, particu- larmente, da robótica aplicada à sempre há capa- cidade financeira para absorver as novas tecnologias, mas que, "apesar de tudo, os robots

  10. Devices and process for high-pressure magic angle spinning nuclear magnetic resonance

    DOE Patents [OSTI]

    Hoyt, David W; Sears, Jr., Jesse A; Turcu, Romulus V.F.; Rosso, Kevin M; Hu, Jian Zhi

    2014-04-08

    A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.

  11. THE FIRST ACCURATE PARALLAX DISTANCE TO A BLACK HOLE

    E-Print Network [OSTI]

    Miller-Jones, J. C. A.

    Using astrometric VLBI observations, we have determined the parallax of the black hole X-ray binary V404 Cyg to be 0.418 [plus or minus sign] 0.024 mas, corresponding to a distance of 2.39 [plus or minus sign] 0.14 kpc, ...

  12. 2/15/2014 Investigadores criam micro-monhos capazes de carregar o telemvel | Sociedade : Cincia e Tecnologia | Dirio Digital http://diariodigital.sapo.pt/news.asp?id_news=679551 1/1

    E-Print Network [OSTI]

    Chiao, Jung-Chih

    . Parece inusitado, mas a dupla pretende usar a energia eólica para carregar telemóveis, utilizando gerar energia do movimento do ar. Para isso, este precisaria de ser balançado, para gerar movimento poderiam ser posicionados na parte lateral de um prédio para fornecer energia. Todos os comentários estão

  13. Resolver o problema do armazenamento de energia

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    Resolver o problema do armazenamento de energia OS SUPERCONDENSADORES CHARGE2CHANGE (C2C) PROMETEM EM SEGUNDOS, COM ENERGIA PARA HORAS, PODE SER UMA REALIDADE PRÓXIMA. Passaram dois séculos sobre muita energia mas demoram a carregar, ou a supercondensadores, que apesar de terem menor capacidade de

  14. Contributed Paper Predicting and Mapping Potential Whooping Crane

    E-Print Network [OSTI]

    Minor, Emily

    para Proyectos de Energ´ia E´olica Resumen: Los h´abitats de descanso migratorio frecuentemente no son que el desarrollo de energ´ia e´olica se vuelva cada vez m´as importante. Usamos esta informaci como de bajo riesgo para conflictos entre las grullas y el desarrollo de energ´ia e´olica. Sugerimos

  15. A&A manuscript no. (will be inserted by hand later)

    E-Print Network [OSTI]

    Taylor, Greg

    .20.2; 05.01.1); ASTRONOMY AND ASTROPHYSICS VLBI Observations of GRB Afterglows G. B. Taylor 1 , A. J. Beasley 1 , D. A. Frail 1 , S. R. Kulkarni 2 , & J. E. Reynolds 3 1 National Radio Astronomy Observatory 0.3 mas corresponding to a distance limit of ?3 kpc (Taylor et al. 1997; Taylor et al. 1998

  16. Revising Knowledge in Multi-Agent System Using Preferences

    E-Print Network [OSTI]

    Pivkina, Inna

    Introduction Multi-Agents Systems (MAS) require coordination mechanisms to facilitate dynamic collaboration way of encoding policies for the integration of agent-generated knowledge (e.g., in a mediator) family of revisions. Each revision represents an updated version of the origi- nal knowledge base

  17. Heteronuclear Recoupling in Solid-State Magic-Angle-Spinning NMR via Overtone Irradiation

    E-Print Network [OSTI]

    Frydman, Lucio

    Heteronuclear Recoupling in Solid-State Magic-Angle-Spinning NMR via Overtone Irradiation Sungsool undergoing magic-angle- spinning (MAS) is introduced, based on the overtone irradiation of one of the coupled nuclei. It is shown that when I is a quadrupole, for instance 14N, irradiating this spin at a multiple

  18. Inteligncia Artificial Gigantes tecnolgicos como a Google e o Facebook apostam tudo na criao de programas que consigam aprender, conversar

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    Inteligência Artificial Gigantes tecnológicos como a Google e o Facebook apostam tudo na criação de tecnológica. Mas está longe de ser a única em marcha. Grandes potên- cias como a Google e o Facebook estão utilizado- res um ano após o lançamento." O gigante Facebook também tem me- tas ambiciosas nesta área

  19. -A Science Service Fca*ture WHY THE WEATHER 7

    E-Print Network [OSTI]

    -A Science Service Fca*ture WHY THE WEATHER 7 By D r . Charlee F, B ~ o o k s of Clark University n 1916- 'rith the duration of periodic weather relationships, this mas haxllg discovered it s t o p

  20. Boletin de la Asociacion Matematica Venezolana, Vol. XI, No. 1 (2004) 127 Formulas Elegantes: Grandes ecuaciones de la Ciencia Moderna

    E-Print Network [OSTI]

    Arratia, Argimiro A.

    2004-01-01

    y la magia de las ecuaciones que fundamentan diversas teor´ias cient´ificas del siglo XX. Encuentro Dirac, "es m´as inteligente que ´el " porque no s´olo describe el comportamiento del electr´on, motivo (profesora de Matem´aticas en Oxford), que sienta las bases de una teor´ia universal que intenta deducir a la

  1. About Raising Children (Spanish) 

    E-Print Network [OSTI]

    Warren, Judith L.

    2002-01-04

    significa establecer y adherirse a nor- mas de comportamiento. Despu?s del amor, los padres subrayan la importancia de dar direcci?n clara y hacer que los ni?os cumplan con las normas de conducta. Disciplina es una preparaci?n esencial para adaptarse al...

  2. Professional and Student Organizations: Earth & Environmental Science BS

    E-Print Network [OSTI]

    Walker, Lawrence R.

    : Association for Environmental Studies and Sciences (AESS) www.aess.info American Geological Institute (AGI' Water Resources Management Program (WRM) and Masters' of Arts and Science program (MAS). http of their broad training in the fundamental sciences, math, and natural phenomena and processes, Earth Scientists

  3. A TEORIA DE RUSSO-SEYMOUR-WELSH E ALGUMAS CONSEQ UENCIAS REMY SANCHIS

    E-Print Network [OSTI]

    Friedli, Sacha

    A TEORIA DE RUSSO-SEYMOUR-WELSH E ALGUMAS CONSEQ ¨UENCIAS R´EMY SANCHIS Apresentaremos alguns resultados conhecidos como Teoria de Russo-Seymour-Welsh para percola¸c~ao inde- pendente de arestas em Z2 rigorosamente que pc = 1/2 para esse modelo e Russo percebeu (ao mesmo tempo, mas inde- pendentemente, Seymour e

  4. THE NORTHERN FUR SEAL FISH A>jm WILDLIFE SERVICE-

    E-Print Network [OSTI]

    rook- eries on Mas-a-Fuero, Juan Fernandez, the South Shetlands, Prince Edward, the AntipodesSHfeRlES Circular 169 « ! #12;prifig^Ssl^s yjy^pven ystanS Breeding grounds of the northern fur seals: Robben Island (Kaihyoto or Tyuleniy Island) off Sakhalin; the Commander Islands (Bering Island and Medny or Copper Island

  5. Correccion Variacional de la Adherencia con Regularizacion Direccional aplicada a

    E-Print Network [OSTI]

    Correcci´on Variacional de la Adherencia con Regularizaci´on Direccional aplicada a Modelos radar, la altimetr´ia laser o los lidar, producen resultados precisos a un costo mucho m´as razonable inversamente proporcional a su distancia a las c´amaras. Los m´etodos autom´aticos para determinar modelos de

  6. Sr. Achievement Awards - 7 

    E-Print Network [OSTI]

    Unknown

    2011-08-17

    environments for grain yield.....................69 Expected genetic gain .................................................................71 Preliminary assessment of MAS efficiency in testcrosses...... ...73 Population CML440/COMPE... and their standard errors (SE) for experiment CML441 x CML444 across all environments in Malawi and Zimbabwe in 2003 and 2004?????????????????????????????. 71 24 Expected genetic gain for grain yield (Mg ha-1) per environment for population CML441 x CML...

  7. EL PAS, mircoles 12 de mayo de 2004 SOCIEDAD / 47 n los jardines que circundan los edifi-

    E-Print Network [OSTI]

    Fernández de Córdoba, Pedro

    , pretende demos- trar que la utilización de la transferencia de calor con el suelo redundaría en siste- mas intercambio de calor con el suelo para la climatización de 12 despachos y un aula del Departamento de y refrigeración del edificio a partir del calor residual del suelo --de carácter renovable

  8. Board Interlocks and the Diffusion of Strategic Actions 

    E-Print Network [OSTI]

    Lamb, Nai Hua

    2014-04-10

    . In this dissertation, I specifically focus on mergers and acquisitions (M&As) in emerging markets as the strategic action of interest. Next, I turn to the theory of triads in structural sociology and examine the influence of a closed triad. I theorize that Simmelian...

  9. 522 Florida Entomologist 87(4) December 2004 MONITORING AND MANAGEMENT OF RED

    E-Print Network [OSTI]

    Watson, Craig A.

    presencia de altas poblaciones pueden interferir con actividades de trabajo. El método mas eficáz para densidades bajas de nidos y cuando se usa- ron umbrales de conteo altos de las hormigas para indicar fue aplicado entre las lagunas, con alguna entrada inevitable de cebo en la laguna. Las densidades de

  10. Matching a Human Walking Sequence with a VRML Synthetic Model

    E-Print Network [OSTI]

    Buades Rubio, Jose María

    animation, computer vision, medical rehabilitation, virtual reality and entertainment. There is a greatMatching a Human Walking Sequence with a VRML Synthetic Model J. M. Buades, Ramon Mas and Francisco University of the Balearic Islands 07071 Palma de Mallorca, SPAIN {josemaria,ramon,paco}@anim.uib.es Abstract

  11. UNIVERSIDADE TECNICA DE LISBOA INSTITUTO SUPERIOR TECNICO

    E-Print Network [OSTI]

    Lisboa, Universidade Técnica de

    ao calculo pi com comunicac¸~ao segura, certificados, mas sem uso expl´icito de crip- tografia. Nesta dissertac¸~ao uma outra ´algebra de processos, tamb´em simi- lar ao c´alculo pi, que nos permite expressar e

  12. Lick Northern Proper Motion Program. III. Lick NPM2 Catalog

    E-Print Network [OSTI]

    Robert B. Hanson; Arnold R. Klemola; Burton F. Jones; David G. Monet

    2004-06-07

    The Lick Northern Proper Motion (NPM) program, a two-epoch (1947-1988) photographic survey of the northern two-thirds of the sky (Dec. > -23 deg), has measured absolute proper motions, on an inertial system defined by distant galaxies, for 380,000 stars from 8 14) anonymous stars for astrometry and galactic studies, 92,000 bright (B < 14) positional reference stars, and 35,000 special stars chosen for astrophysical interest. The NPM2 proper motions are on the ICRS system, via Tycho-2 stars, to an accuracy of 0.5 mas/yr in each field. RMS proper motion precision is 6 mas/yr. Positional errors average 80 mas at the mean plate epoch 1968, and 200 mas at the NPM2 catalog epoch 2000. NPM2 photographic photometry errors average 0.18 mag in B, and 0.20 mag in B-V. The NPM2 Catalog and the updated (to J2000) NPM1 Catalog are available at the CDS Strasbourg data center and on the NPM WWW site (http://www.ucolick.org/~npm). The NPM2 Catalog completes the Lick Northern Proper Motion program after a half-century of work by three generations of Lick Observatory astronomers. The NPM Catalogs will serve as a database for research in galactic structure, stellar kinematics, and astrometry.

  13. EVN and MERLIN confirmation of the LS5039 jets

    E-Print Network [OSTI]

    J. M. Paredes; M. Ribo; E. Ros; J. Marti; M. Massi

    2002-07-09

    The microquasar nature of LS5039 was revealed by May 1999 VLBA+VLA observations showing a two-sided jet at milliarcsecond scales. Here we present follow-up interferometric observations carried out with the EVN and MERLIN at 5 GHz in March 2000. The obtained maps with both the EVN and MERLIN show a two-sided jet with a similar position angle to the previous VLBA+VLA map. The total length of the jet arms is ~60 mas in the EVN map and ~300 mas in the MERLIN map. A brightness and length asymmetry of the jets, compatible with the earlier observations, is also present in the maps. Overall, these observations confirm the existence of a two-sided jet structure in LS 5039 and seem to indicate their persistent nature.

  14. The First U.S. Naval Observatory Robotic Astrometric Telescope Catalog (URAT1)

    E-Print Network [OSTI]

    Zacharias, Norbert; Subasavage, John; Bredthauer, Greg; Crockett, Chris; DiVittorio, Mike; Ferguson, Erik; Harris, Fred; Harris, Hugh; Henden, Arne; Kilian, Chris; Munn, Jeff; Rafferty, Ted; Rhodes, Al; Schultheiss, Mike; Tilleman, Trudy; Wieder, Gary

    2015-01-01

    URAT1 is an observational, astrometric catalog covering most of the Dec >= -15 deg area and a magnitude range of about R = 3 to 18.5. Accurate positions (typically 10 to 30 mas standard error) are given for over 228 million objects at a mean epoch around 2013.5. For the over 188 million objects matched with the 2MASS point source catalog proper motions (typically 5 to 7 mas/yr std. errors) are provided. These data are supplemented by 2MASS and APASS photometry. Observations, reductions and catalog construction are described together with results from external data verifications. The catalog data are served by CDS, Starsbourg (I/329). There is no DVD release.

  15. High-burnup core design using minor actinide-containing metal fuel

    SciTech Connect (OSTI)

    Ohta, Hirokazu; Ogata, Takanari; Obara, T.

    2013-07-01

    A neutronic design study of metal fuel fast reactor (FR) cores is conducted on the basis of an innovative fuel design concept to achieve an extremely high burnup and realize an efficient fuel cycle system. Since it is expected that the burnup reactivity swing will become extremely large in an unprecedented high burnup core, minor actinides (MAs) from light water reactors (LWRs) are added to fresh fuel to improve the core internal conversion. Core neutronic analysis revealed that high burnups of about 200 MWd/kg for a small-scale core and about 300 MWd/kg for a large-scale core can be attained while suppressing the burnup reactivity swing to almost the same level as that of conventional cores with normal burnup. An actinide burnup analysis has shown that the MA consumption ratio is improved to about 60% and that the accumulated MAs originating from LWRs can be efficiently consumed by the high-burnup metal fuel FR. (authors)

  16. BRORFELDE SCHMIDT CCD CATALOG

    SciTech Connect (OSTI)

    Zacharias, N.; Finch, C.; Wycoff, G. L.; Einicke, O. H.; Augustesen, K.; Clausen, J. V.; Hoeg, E.

    2010-08-15

    The Brorfelde Schmidt CCD Catalog (BSCC) contains about 13.7 million stars, north of +49{sup 0} decl. with precise positions and V, R photometry. The catalog has been constructed from the reductions of 18,667 CCD frames observed with the Brorfelde Schmidt Telescope between 2000 and 2007. The Tycho-2 catalog was used for astrometric and photometric reference stars. Errors of individual positions are about 20-200 mas for stars in the R = 10-18 mag range. External comparisons with the Two Micron All-Sky Survey (2MASS) and Sloan Digital Sky Survey reveal possible small systematic errors in the BSCC of up to about 30 mas. The catalog is supplemented with J, H, and K{sub s} magnitudes from the 2MASS catalog.

  17. VLBI AND ARCHIVAL VLA AND WSRT OBSERVATIONS OF THE GRB 030329 RADIO AFTERGLOW

    SciTech Connect (OSTI)

    Mesler, Robert A.; Pihlstroem, Ylva M.; Taylor, Greg B. [Department of Physics and Astronomy, University of New Mexico, MSC07 4220, Albuquerque, NM 87131 (United States); Granot, Johnathan, E-mail: meslerra@unm.edu [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom)

    2012-11-01

    We present VLBI and archival Karl G. Jansky Very Large Array (VLA) and Westerbork Synthesis Radio Telescope (WSRT) observations of the radio afterglow from the gamma-ray burst (GRB) of 2003 March 29 (GRB 030329) taken between 672 and 2032 days after the burst. The VLA and WSRT data suggest a simple power-law decay in the flux at 5 GHz, with no clear signature of any rebrightening from the counterjet. We report an unresolved source at day 2032 of size 1.18 {+-} 0.13 mas, which we use in conjunction with the expansion rate of the burst to argue for the presence of a uniform, interstellar-medium-like circumburst medium. A limit of <0.067 mas yr{sup -1} is placed on the proper motion, supporting the standard afterglow model for gamma-ray bursts.

  18. Regnar -- Development of a marginal field

    SciTech Connect (OSTI)

    Thalund, K.M.; Brodersen, F.P.; Roigaard-Petersen, B.

    1994-12-31

    Regnar is a small marginal field located some 13 km from the main Dan F complex and is the first subsea completion in Danish waters, operated by Maersk Olie og Gas AS. A short lifetime has been predicted for the field which therefore has been developed as a low cost project, using a combination of subsea technology and minimum topside facilities. Regnar consists of a subsea x-mas tree producing through a 6 inch pipeline with a 2 1/2 inch chemical piggyback line to Dan F. The x-mas tree and the subsea choke valve are controlled from a buoy moored nearby the well. The buoy is radio linked to Dan F. The Regnar field was brought on stream on September 26, 1993.

  19. Rapid estimation of 4DCT motion-artifact severity based on 1D breathing-surrogate periodicity

    SciTech Connect (OSTI)

    Li, Guang Caraveo, Marshall; Wei, Jie; Rimner, Andreas; Wu, Abraham J.; Goodman, Karyn A.; Yorke, Ellen

    2014-11-01

    Purpose: Motion artifacts are common in patient four-dimensional computed tomography (4DCT) images, leading to an ill-defined tumor volume with large variations for radiotherapy treatment and a poor foundation with low imaging fidelity for studying respiratory motion. The authors developed a method to estimate 4DCT image quality by establishing a correlation between the severity of motion artifacts in 4DCT images and the periodicity of the corresponding 1D respiratory waveform (1DRW) used for phase binning in 4DCT reconstruction. Methods: Discrete Fourier transformation (DFT) was applied to analyze 1DRW periodicity. The breathing periodicity index (BPI) was defined as the sum of the largest five Fourier coefficients, ranging from 0 to 1. Distortional motion artifacts (excluding blurring) of cine-scan 4DCT at the junctions of adjacent couch positions around the diaphragm were classified in three categories: incomplete, overlapping, and duplicate anatomies. To quantify these artifacts, discontinuity of the diaphragm at the junctions was measured in distance and averaged along six directions in three orthogonal views. Artifacts per junction (APJ) across the entire diaphragm were calculated in each breathing phase and phase-averaged APJ{sup ¯}, defined as motion-artifact severity (MAS), was obtained for each patient. To make MAS independent of patient-specific motion amplitude, two new MAS quantities were defined: MAS{sup D} is normalized to the maximum diaphragmatic displacement and MAS{sup V} is normalized to the mean diaphragmatic velocity (the breathing period was obtained from DFT analysis of 1DRW). Twenty-six patients’ free-breathing 4DCT images and corresponding 1DRW data were studied. Results: Higher APJ values were found around midventilation and full inhalation while the lowest APJ values were around full exhalation. The distribution of MAS is close to Poisson distribution with a mean of 2.2 mm. The BPI among the 26 patients was calculated with a value ranging from 0.25 to 0.93. The DFT calculation was within 3 s per 1DRW. Correlations were found between 1DRW periodicity and 4DCT artifact severity: ?0.71 for MAS{sup D} and ?0.73 for MAS{sup V}. A BPI greater than 0.85 in a 1DRW suggests minimal motion artifacts in the corresponding 4DCT images. Conclusions: The breathing periodicity index and motion-artifact severity index are introduced to assess the relationship between 1DRW and 4DCT. A correlation between 1DRW periodicity and 4DCT artifact severity has been established. The 1DRW periodicity provides a rapid means to estimate 4DCT image quality. The rapid 1DRW analysis and the correlative relationship can be applied prospectively to identify irregular breathers as candidates for breath coaching prior to 4DCT scan and retrospectively to select high-quality 4DCT images for clinical motion-management research.

  20. Hydrocarbon-bridged polysiloxane and polysilsesquioxane network materials

    SciTech Connect (OSTI)

    Jamison, G.M.; Loy, D.A.; Assink, R.A. [Sandia National Labs., Albuquerque, NM (United States). Properties of Organic Materials Dept.; Shea, K.J. [Univ. of California, Irvine, CA (United States). Dept. of Chemistry

    1994-12-31

    Hexylene and phenylene-bridged polymethylsiloxane xerogels X-2 and X-4, respectively, were prepared by the sol-gel hydrolysis and condensation of 1, 6-bis(diethoxymethylsilyl)hexane 1 and 1, 4-bis(diethoxymethylsilyl)benzene 2 under acidic and basic conditions. These polymerizations afforded network polymers in the form of wet gels within several hours. The gels were processed to afford xerogels whose characteristics (determined by solid state {sup 13}C and {sup 29}Si CP MAS NMR spectroscopy and nitrogen sorption porosimetry) were compared and contrasted with those of their analogous polysilsesquioxanes. {sup 29}Si CP MAS NMR indicates a high degree of hydrolysis and polycondensation; porosimetry measurements reveal that the materials have significant surface areas, save for the acid-catalyzed hexylene gels X-2.

  1. PRESTO polarization transfer to quadrupolar nuclei: Implications for dynamic nuclear polarization

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Perras, Frédéric A.; Kobayashi, Takeshi; Pruski, Marek

    2015-08-04

    We show both experimentally and numerically on a series of model systems that in experiments involving transfer of magnetization from 1H to the quadrupolar nuclei under magic-angle-spinning (MAS), the PRESTO technique consistently outperforms traditionally used cross polarization (CP), affording more quantitative intensities, improved lineshapes, better overall sensitivity, and straightforward optimization. This advantage derives from the fact that PRESTO circumvents the convoluted and uncooperative spin dynamics during the CP transfer under MAS, by replacing the spin-locking of quadrupolar nuclei with a single central transition selective 90° pulse and using a symmetry-based recoupling sequence in the 1H channel. This is important inmore »the context of dynamic nuclear polarization (DNP) NMR of quadrupolar nuclei, where the efficient transfer of enhanced 1H polarization is desired to obtain the highest sensitivity.« less

  2. Dise~no de redes en chip de proposito especifico con informacion de rutado fisico

    E-Print Network [OSTI]

    De Micheli, Giovanni

    ~nar NoCs a me- dida para cada tipo de aplicaci´on que se desea ejecutar en los SoCs. En este art interconexionado. Este nuevo flujo de dise~no define e instancia de manera compl´etamente autom´atica el c posibles alterna- tivas de dise~no manual basadas en NoCs m´as regulares tipo malla, Clos, etc. Palabras

  3. CONVOLUCI ' 1 Introducci'on matem'atica

    E-Print Network [OSTI]

    Barreiro, Alvaro

    verticales en una imagen. Puede calcular las derivadas de la imagen en direcci'on horizontal; las derivadas arbitrariamente peque~no. Si la unidad de medida es el pixel tenemos \\Deltax = 1 y una aproximaci'on a la derivada proceso de a~nadir m'as generalizaci'on, podr'ia pensarse en una definici'on centrada de la derivada: @F

  4. A Morta de Oswald de Andrade: A Emergência de uma mímesis Paradoxal no Teatro Brasileiro

    E-Print Network [OSTI]

    Vasconcelos Avelar, Idelber

    1995-10-01

    , é em A Morta (1937), "peça de menor viabilidade cénica" (191), segundo Sábato Magaldi, que Oswald mais avança na elaboração de um teatro de vanguarda. Cai definitivamente a quarta parede que separa os espaços do espectador e da representação... teatral," "performance," mas principalmente em termos semióticos mais amplos, no sentido da relação particular que o texto oswaldiano estabelece entre o signo teatral—seja ele sonor, visual, etc.—e seu referente? Não basta dizer que em Oswald esta...

  5. Na Crista da Onda por Mais de 100 anos. Fabio Chalub e Jorge Zubelli

    E-Print Network [OSTI]

    Zubelli, Jorge Passamani

    . (...) #19; E isto que uma eleva#24;c~ao de #19;agua faz: ela n~ao permanece onde est#19;a, mas viaja repente, a embar- ca#24;c~ao parou. A massa d'#19;agua que esta arrastava, no entanto, continuou, foi;erie": acumulando #19; agua em uma extremi- dade de um canal raso separada por um anteparo e, de

  6. Fisica atomica, molecular y materia condensada Entrega 24 de marzo de 2010 antes de la clase

    E-Print Network [OSTI]

    Noguez, Cecilia

    clase 1. Escribe el Hamiltoniano del ´atomo de Litio (Li) con n´umero at´omico Z=3. Encuentra la energ´ametro. Encuentra la energ´ia del estado base optimizando el par´ametro para obtener la energ´ia m´as baja. Ca´lcula las energ´ias de la primera y segunda ionizaciones. 3. Escribe el determinante de Slater ara el ´atomo

  7. Nac onal~na akadem nauk Ukra ni KONDENSOVANIH

    E-Print Network [OSTI]

    tral~nih atom v operator energ h vza mod vz ti u vigl d mul~tipol~nogo r du 1], to v me ah kvantovo-Oppenge mera voni potenc al~- no energ dl centr v mas atom v qi efektivno m atomno vza mod . Zastosovu qi danu prit gann energ proporc na do R 6 (R - v dstan~ m atomami). kwo atomi toto n perebuva t~ v stanah z r

  8. 4.6. Calculo de volumenes de cubos con aristas que sean curvas coordenadas

    E-Print Network [OSTI]

    Morin, Pedro

    (cuantitativamente) la evoluci´on espacio-temporal de una cantidad U en . Por ejemplo, la energ´ia t´ermica, la masa es energ´ia t´ermica. M´as precisamente, suponemos que si E = E(; t) es la energ´ia t´ermica en la regi´on a tiempo t, entonces la densidad de energ´ia t´ermica e = e(x1, x2, x3; t) es la propiedad

  9. The dynamical evolution of the fragmented, bipolar dust shell around the carbon star IRC +10216: Rapid changes of a PPN-like structure?

    E-Print Network [OSTI]

    R. Osterbart; Y. Balega; T. Bloecker; A. Men'shchikov; G. Weigelt

    2000-03-22

    We present high-resolution J-, H-, and K-band observations and the first H-K color image of the carbon star IRC +10216. The images were reconstructed from 6m telescope speckle interferograms using the bispectrum speckle interferometry method. The H and K images with resolutions between 70mas and 92mas consist of several compact components within a 0.2" radius and a fainter asymmetric nebula. The brightest four components are denoted with A to D in the order of decreasing brightness in the 1996 image. A comparison of our images from 1995, 1996, 1997, and 1998 gives - almost like a movie of five frames - insight into the dynamical evolution of the inner nebula. For instance, the separation of the two brightest components A and B increased from 191 mas in 1995 to 265 mas in 1998. At the same time, component B is fading and the components C and D become brighter. The X-shaped bipolar structure of the nebula, most prominently present in the J-band image, implies an asymmetric mass loss. Such asymmetries are often present in protoplanetary nebulae but are unexpected for AGB stars. IRC +10216 is thus likely to be very advanced in its AGB evolution, shortly before turning into a protoplanetary nebula. The cometary shapes of A in the H and J images and in the 0.79 micron and 1.06 micron HST images suggest that the core of A is not the central star, but the southern lobe of a bipolar structure. The position of the central star is probably at or near the position of component B, where the H-K color has a value of 4.2. If the star is at or near B, then the components A, C, and D are likely to be located at the inner boundary of the dust shell.

  10. Using High-Resolution NMR to Examine the Components that Contribute to the Activity and Stability of Phosphatase of Regenerating Liver (PRL-1) and Their Dependence on the Redox State of Cysteine Residues

    E-Print Network [OSTI]

    Skinner, Andria L.

    2009-12-15

    number R-017708. The mas spectrometers used in this study were purchased with support from KSTAR, Kansas administered NSF EPSCoR, the University of Kansas and KCALSI (ww.kclifesciences.org). This study also made use of the National Magnetic Resonance... Vander Velde and Dr. Asokan Anabanadam for their support, training and maintenance of the NMR spectrometers here at KU. Additional NMR training was received at the National Magnetic Resonance Facility at Madison (NMRFAM) Protein Structure Determination...

  11. 1.2 Variedades de curvas. O objetivo desta se,c"ao 'e em primeiro lugar o de especializar alguns resu*

    E-Print Network [OSTI]

    Tausk, Daniel Victor

    - eraliza,c"oes para espa,cos de se,c"oes de um fibrado geral, mas o objetivo des* *ta se,c"ao 'e jus N agora passa a ser chamad* *a de M. Teremos sempre um tipo M de espa,co de se,c"oes que fibrado misto sobre I (cu* *jo fibrado das bases 'e I x M). Teremos ent"ao dois tipos M1, M2 de espa

  12. Mec^anica Geometrica A entregar ate `a aula de Quarta-feira dia 27 de Outubro

    E-Print Network [OSTI]

    Natário, José

    Sistema Solar conservam o momento angular mas tendem a dissipar energia). 3. (a) Mostre que a express¸c~oes em torno de e3 s~ao est´aveis. (c) Se I1 > I2 > I3 ent~ao para um dado momento angular a energia cin~ao local da energia cin´etica de um corpo r´igido com um ponto fixo e I1 = I2 nas coordenadas de TSO(3

  13. Exame de Mecanica Geometrica Jose Natario

    E-Print Network [OSTI]

    Natário, José

    = r sen # cos # y = r sen # sen # z = r cos # e que a energia cinâ??etica de uma partâ??�cula de massa m luz. Em desespero de causa, decide­se instalar um motor experimental na Enterprise que teoricamente lhe permitirâ??a al­ canâ?ºcar 80% da velocidade da luz. A instalaâ?ºcâ?ao demora 1 ano, mas o novo motor

  14. Minor Actinides Loading Optimization for Proliferation Resistant Fuel Design - BWR

    SciTech Connect (OSTI)

    G. S. Chang; Hongbin Zhang

    2009-09-01

    One approach to address the United States Nuclear Power (NP) 2010 program for the advanced light water reactor (LWR) (Gen-III+) intermediate-term spent fuel disposal need is to reduce spent fuel storage volume while enhancing proliferation resistance. One proposed solution includes increasing burnup of the discharged spent fuel and mixing minor actinide (MA) transuranic nuclides (237Np and 241Am) in the high burnup fuel. Thus, we can reduce the spent fuel volume while increasing the proliferation resistance by increasing the isotopic ratio of 238Pu/Pu. For future advanced nuclear systems, MAs are viewed more as a resource to be recycled, and transmuted to less hazardous and possibly more useful forms, rather than simply disposed of as a waste stream in an expensive repository facility. MAs play a much larger part in the design of advanced systems and fuel cycles, not only as additional sources of useful energy, but also as direct contributors to the reactivity control of the systems into which they are incorporated. A typical boiling water reactor (BWR) fuel unit lattice cell model with UO2 fuel pins will be used to investigate the effectiveness of adding MAs (237Np and/or 241Am) to enhance proliferation resistance and improve fuel cycle performance for the intermediate-term goal of future nuclear energy systems. However, adding MAs will increase plutonium production in the discharged spent fuel. In this work, the Monte-Carlo coupling with ORIGEN-2.2 (MCWO) method was used to optimize the MA loading in the UO2 fuel such that the discharged spent fuel demonstrates enhanced proliferation resistance, while minimizing plutonium production. The axial averaged MA transmutation characteristics at different burnup were compared and their impact on neutronics criticality and the ratio of 238Pu/Pu discussed.

  15. Matematica Discreta Asignatura optativa de la Licenciatura de Matematicas (UAM)

    E-Print Network [OSTI]

    Quirós, Fernando

    de sus v´ertices son de grado 4, y los restantes de grado 3. 2. Demu´estrese que en todo grafo conexo con m´as de dos v´ertices tiene que haber al menos dos v´ertices con el mismo grado. 3. Demu´estrese estudiantes se van de vacaciones y deciden que cada uno escribir´a una tarjeta a los otros tres. ¿Es posible

  16. COBI cobi12199 Dispatch: October 31, 2013 CE: AFL Journal MSP No. No. of pages: 10 PE: XXXXX1

    E-Print Network [OSTI]

    Minor, Emily

    fuentes de energ´ia limpias y renovables. Hasta el 54% de nuestra ´area de estudio fue predicha como´abitat Potencial de Descanso de la Grulla Americana para Guiar la Selecci´on de Sitios para Proyectos de Energ´ia E energ´ia e´olica se vuelva cada vez m´as importante. Usamos esta informaci´on para identificar ´areas

  17. Separoides: el Complejo de Radon

    E-Print Network [OSTI]

    Strausz, Ricardo

    meses de trabajo en mi tesis hubieran sido imposibles sin la compa~nia de mi amigo Juancho y la, quisiera dedicar esta tesis a una bola de amiguitos que conoc´i durante el paro que sufri´o nustra m, resulta ser la latiz de caras de una esfera. Los ejemplos m´as claros de la teor´ia surgen de la geometr

  18. Environments of deposition and diagenesis of the Jurassic Upper Smackover Formation in the Lincoln Parish area, Louisiana 

    E-Print Network [OSTI]

    Palko, Gregory Jonathan

    1980-01-01

    and intraclastic grainstones, argillaceous, dolomitic mudstones to wackestones with nodular anhydrite stringers, and some mas- sive, bioturbated litharenites, graded litharenites, silt- stones and shales. The two shoaling upwards grainstone cycles that were... is present between the cycles i . +he landward core. I+ is a +idal lat microfacies on the lee o. the island ti at develoved during deposition of the "z lime" or lower shoaling cycle. inter-'idee trough or salt withdrawal basin in the southern vast of +he...

  19. Historia de la Probabilidad y la Estadistica [IV] (J. Basulto y J. J. Garcia, eds.) Huelva: Servicio de Publicaciones de la Universidad de Huelva

    E-Print Network [OSTI]

    Gómez Villegas, Miguel Ángel

    16 a~nos fu´e retirado de la escuela por motivos de salud, y pasa el a~no siguiente con un preceptor nueva ´epoca en la teor´ia y en la pr´actica de la estad´istica. Entre 1893 y 1906 publica unos 100 art, a lo largo de su vida public´o m´as de 650 art´iculos,

  20. X-shooter Science Verification Proposal A special co-moving white dwarfmain sequence pair

    E-Print Network [OSTI]

    Liske, Jochen

    and HD 122750 form a co-moving proper motion pair (PM in mas/yr: RA, Dec, from UCAC-2): WD 1401-147 (-170: The white dwarf (WD) WD 1401-147 and the main sequence (MS) star HD 122750 form a co-moving proper motion laboratory to study the complex physics of pulsating WDs in a quantitative manner. Scientific Case: WD 1401-147

  1. UPVCurry: Un int'erprete de Curry con tipos polim'orficos y E/S declarativa mon'adica \\Lambda

    E-Print Network [OSTI]

    Escobar, Santiago

    evaluaci'on y b'usqueda encapsulada. De la programaci'on l'ogica, se obtienen las variables l programaci'on declarativos proporcionan un estilo de programaci'on potente que reduce el tiempo de desarrollo1997­0073. 1 #12; Despu'es de m'as de dos d'ecadas de investigaci'on en el campo de la Programaci'on

  2. Biodiversity and Biogeography of an Important Inbred Pest of Coffee, Coffee Berry Borer (Coleoptera: Curculionidae: Scolytinae)

    E-Print Network [OSTI]

    Romero-Severson, Jeanne

    dactilares gene´ticas examinando la variacio´n gene´tica y la biogeograÞa de la plaga mas importante del dactilares (haplotipos) fueron descubiertas. La variacio´n gene´tica fue extremadamente baja (10% promedio de polimorÞsmos por muestra), pero la diferenciacio´n gene´tica fue alta ( ST 0.464). La distribucio´n de las

  3. Post operational investigation of the recovered North East Frigg subsea production equipment after 10 year`s service

    SciTech Connect (OSTI)

    Worley, L.J.; Fjaertoft, L.

    1995-12-31

    Elf Petroleum Norge had for 10 years been operating the North East Frigg field. This gas field was the first subsea field on the Norwegian Continental shelf. It was shut down on the 8th May 1993. Elf Petroleum Norge used the shut down as an ideal opportunity to review the performance of the subsea equipment. An investigation was initiated,its purpose, to gather information regarding the history, wear, effect of cathodic protection, corrosion etc from the X-mas tree components.

  4. arXiv:0803.3834v2[quant-ph]26May2009 The meaning of 1 in j(j+1)

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    del momento angular (J2) en mec´anica cu´antica es mas grande que lo esperado en un modelo cl´asico. Explicamos esta diferencia en t´erminos de las fluctuaciones cu´anticas. Un c´alculo est´andar de mec´anica cu´antica da la interpretaci´on correcta a las componentes del momento angular en el modelo vectorial

  5. Las ágiles musas de la modernidad: Patricia Galvão y Norah Lange

    E-Print Network [OSTI]

    Unruh, Vicky

    1998-05-01

    mujeres 'Las novelas de Galvao incluyen Parque Industrial (1933) y Afamosa revista (1945), escrita con Geraldo Ferraz. La antologia de obra creativa y critica, Pagiu- Vida-O bra, publicada en 1982 por Augusto de Campos, contiene selecciones de su poesia... musa previa de Oswald de Andrade.8 Galvflo, declamadora de poesia, public6 dibujos en la Revista de Antropofagia. La critica reciente la ha venerado como la encarnacion del espiritu de su epoca: "el simbolo mas esencial de todo lo nuevo, lo...

  6. Workshop: Analysis and Concepts to Address Electric Infrastructure Needs

    E-Print Network [OSTI]

    .hahn@nypa.gov 19. Steve Foltyn LANL sfoltyn@lanl.gov 20. Julian Cave Hydro Quebec cave.julian@ireq.ca 21. Soo Yeau DOE roland.george@ee.doe.gov 35. Masaki Suenaga BNL mas@bnl.gov 36. Mike Crews Duke Energy mrcrews@duke-energy@istec.or.jp 41. Robb Turner Arclight Capital rturner@archlightcapital.com 42. William V. Hassenzahl Adv. Energy

  7. A Rating of Plants with Reference to their Relative Resistance or Susceptibility to Phymatotrichum Root Rot. 

    E-Print Network [OSTI]

    Taubenhaus, J. J. (Jacob Joseph); Ezekiel, Walter N. (Walter Naphtali)

    1936-01-01

    , a co-operativc experi- ment mas begun in 1890 with stations at Mississippi, Naryland, Georgia, Connecticut, New York, Wisconsin and Kansas. Previous work and observation had lead to the belief that such a variation would be found to exist... too mucn work upon the chenlists at the several stations. Owing to drouth, and other unavoidable causes, reports have been received from but three stations. That of Connecticut, Georgia and New York. Of the corn grown in Connecticut 1890 but two...

  8. -A Science Service Peatwe Released upon receipt

    E-Print Network [OSTI]

    -A Science Service Peatwe Released upon receipt but inteniied for use July 18, 1931 ? c7;Iy m U32v, with the cooperation of the U. S. Veather Bureau, as a contri- bution to the scYudy of hqy fever, show that the crop the first tine, the survey mas extended into Canada, where lrThe corn crop,fI writes Mr. Durham, Itnay

  9. UNIVERSIDADE T ' ECNICA DE LISBOA

    E-Print Network [OSTI]

    Lisboa, Universidade Técnica de

    a qual se pretende estabelecer uma semâ??antica operacional. Para tal, introduz­se um c'alculo de objectosCO, semelhante aos do C'alculo­â??, mas que atribui tipos aos nomes e tipifica¸c~oes (conjuntos de pares nome type of invariance properties, concluding that it is not possible. #12; Palavras Chave / Keywords C'alculo

  10. Hubble space telescope absolute proper motions of NGC 6681 (M70) and the sagittarius dwarf spheroidal galaxy

    SciTech Connect (OSTI)

    Massari, D.; Ferraro, F. R.; Dalessandro, E.; Lanzoni, B. [Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, v.le Berti Pichat 6/2, I-40127 Bologna (Italy); Bellini, A.; Van der Marel, R. P.; Anderson, J. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2013-12-10

    We have measured absolute proper motions for the three populations intercepted in the direction of the Galactic globular cluster NGC 6681: the cluster itself, the Sagittarius dwarf spheroidal galaxy, and the field. For this, we used Hubble Space Telescope ACS/WFC and WFC3/UVIS optical imaging data separated by a temporal baseline of 5.464 yr. Five background galaxies were used to determine the zero point of the absolute-motion reference frame. The resulting absolute proper motion of NGC 6681 is (?{sub ?}cos ?, ?{sub ?}) = (1.58 ± 0.18, –4.57 ± 0.16) mas yr{sup –1}. This is the first estimate ever made for this cluster. For the Sgr dSph we obtain (?{sub ?}cos ?, ?{sub ?}) = –2.54 ± 0.18, –1.19 ± 0.16) mas yr{sup –1}, consistent with previous measurements and with the values predicted by theoretical models. The absolute proper motion of the Galaxy population in our field of view is (?{sub ?}cos ?, ?{sub ?}) = (– 1.21 ± 0.27, –4.39 ± 0.26) mas yr{sup –1}. In this study we also use background Sagittarius Dwarf Spheroidal stars to determine the rotation of the globular cluster in the plane of the sky and find that NGC 6681 is not rotating significantly: v {sub rot} = 0.82 ± 1.02 km s{sup –1} at a distance of 1' from the cluster center.

  11. Outer Rotation Curve of the Galaxy with VERA III: Astrometry of IRAS 07427-2400 and Test of the Density-Wave Theory

    E-Print Network [OSTI]

    Sakai, Nobuyuki; Matsuo, Mitsuhiro; Koide, Nagito; Tezuka, Daisuke; Kurayama, Tomoharu; Shibata, Katsunori M; Ueno, Yuji; Honma, Mareki

    2015-01-01

    We report the trigonometric parallax of IRAS 07427-2400 with VERA to be 0.185 $\\pm$ 0.027 mas, corresponding to a distance of 5.41$^{+0.92}_{-0.69}$ kpc. The result is consistent with the previous result of 5.32$^{+0.49}_{-0.42}$ kpc obtained by Choi et al. (2014) within error. To remove the effect of internal maser motions (e.g., random motions), we observed six maser features associated with IRAS 07427-2400 and determined systematic proper motions of the source by averaging proper motions of the six maser features. The obtained proper motions are ($\\mu_{\\alpha}$cos$\\delta$, $\\mu_{\\delta}$) = ($-$1.79 $\\pm$ 0.32, 2.60 $\\pm$ 0.17) mas yr$^{-1}$ in equatorial coordinates, while Choi et al. (2014) showed ($\\mu_{\\alpha}$cos$\\delta$, $\\mu_{\\delta}$) = ($-$2.43 $\\pm$ 0.02, 2.49 $\\pm$ 0.09) mas yr$^{-1}$ with one maser feature. Our astrometry results place the source in the Perseus arm, the nearest main arm in the Milky Way. Using our result with previous astrometry results obtained from observations of the Perseus...

  12. New method to measure proper motions of microlensed sources: Application to candidate free-floating-planet event MOA-2011-BLG-262

    SciTech Connect (OSTI)

    Skowron, Jan [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Udalski, Andrzej; Szyma?ski, Micha? K., E-mail: jskowron@astrouw.edu.pl, E-mail: udalski@astrouw.edu.pl, E-mail: msz@astrouw.edu.plm [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); and others

    2014-04-20

    We develop a new method to measure source proper motions in microlensing events, which can partially overcome problems due to blending. It takes advantage of the fact that the source position is known precisely from the microlensing event itself. We apply this method to the event MOA-2011-BLG-262, which has a short timescale t {sub E} = 3.8 day, a companion mass ratio q = 4.7 × 10{sup –3}, and a very high or high lens-source relative proper motion ?{sub rel} = 20 mas yr{sup –1} or 12 mas yr{sup –1} (for two possible models). These three characteristics imply that the lens could be a brown dwarf or a massive planet with a roughly Earth-mass 'moon'. The probability of such an interpretation would be greatly increased if it could be shown that the high lens-source relative proper motion was primarily due to the lens rather than the source. Based on the long-term monitoring data of the Galactic bulge from the Optical Gravitational Lensing Experiment, we measure the source proper motion that is small, ?{sub s}=(?2.3,?0.9)±(2.8,2.6) mas yr{sup ?1} in a (north, east) Galactic coordinate frame. These values are then important input into a Bayesian analysis of the event presented in a companion paper by Bennett et al.

  13. Water Maser Kinematics in the Jet of OH 12.8-0.9

    E-Print Network [OSTI]

    David A. Boboltz; Kevin B. Marvel

    2007-06-20

    We present Very Long Baseline Array observations of the kinematics of the water masers associated with OH 12.8-0.9, the fourth member of the so-called "water fountain" class of sources. We find that the masers occupy two distinct regions at the ends of a bipolar jet-like structure oriented north-south, with the blue-shifted masers located to the north and the red-shifted masers to the south. The masers are distributed along arc-like structures 12-20 mas across oriented perpendicular to the separation axis with an angular separation of ~110 mas on the sky. Our multi-epoch observations, show the two maser arcs to be expanding away from each other along the axis of separation. The relative proper motions of the two maser regions is 2.7 mas/yr (~105 km/s at the assumed distance of 8 kpc). The measured radial velocity difference between the northern, blue-shifted masers and the southern, red-shifted masers is 48.4 km/s. The radial velocity, when combined with the proper motion, yields a three-dimensional expansion velocity of 58 km/s and an inclination angle of 24 deg. for the jet. By combining our radial velocities with historical values, we estimate the three dimensional acceleration of the masers to be ~0.63 km/s/yr and a dynamical age for the collimated outflow of ~90 yr.

  14. Development of a generic computerized nuclear material accountability system

    SciTech Connect (OSTI)

    Cornell, M.D.; O'Leary, J.M.; McCutcheon, S.H.

    1987-01-01

    A computerized nuclear material accountability system (NucMAS) has been developed jointly by DuPont at Savannah River Plant (SRP) and Los Alamos National Laboratory (LANL). The SRP is faced with the goal of improving the accuracy and timeliness of nuclear material accountability. Limited manpower, funding, and time led to the decision to develop a single, generic, process-independent computer system for use throughout SRP's separations facilities, rather than traditional process-specific accountability computer systems. The NucMAS system is currently being installed in each of the material balance areas (MBAs) within SRP's separations facilities. It services the basic need for management of nuclear material inventory data to support timely, accurate, and consistent accountability reporting. Data input for NucMAS can come from any combination of manual entries and automated input, such as distributed control systems, laboratory computers, and vault surveillance systems. The system can be operated as a traditional, after-the-fact accountability system or in a near-real-time mode in situations where more timely data input is available and material control functions are desired. The granularity at which the accounting is performed is set by the MBA custodian and the level of detail at which input information is available.

  15. Separated fringe packet observations with the Chara Array. II. ? Andromeda, HD 178911, and ? Cephei

    SciTech Connect (OSTI)

    Farrington, C. D.; Ten Brummelaar, T. A.; Turner, N. H.; Sturmann, L.; Sturmann, J.; Mason, B. D.; Hartkopf, W. I.; Mourard, D.; Moravveji, E.; McAlister, H. A. E-mail: theo@chara-array.org E-mail: sturmann@chara-array.org E-mail: bdm@usno.navy.mil E-mail: denis.mourard@oca.eu E-mail: hal@chara.gsu.edu

    2014-09-01

    When observed with optical long-baseline interferometers, components of a binary star that are sufficiently separated produce their own interferometric fringe packets; these are referred to as separated fringe packet (SFP) binaries. These SFP binaries can overlap in angular separation with the regime of systems resolvable by speckle interferometry at single, large-aperture telescopes and can provide additional measurements for preliminary orbits lacking good phase coverage, help constrain elements of already established orbits, and locate new binaries in the undersampled regime between the bounds of spectroscopic surveys and speckle interferometry. In this process, a visibility calibration star is not needed, and the SFPs can provide an accurate vector separation. In this paper, we apply the SFP approach to ? Andromeda, HD 178911, and ? Cephei with the CLIMB three-beam combiner at the CHARA Array. For these systems we determine component masses and parallax of 0.963 ± 0.049 M {sub ?} and 0.860 ± 0.051 M {sub ?} and 39.54 ± 1.85 mas for ? Andromeda, for HD 178911 of 0.802 ± 0.055 M {sub ?} and 0.622 ± 0.053 M {sub ?} with 28.26 ± 1.70 mas, and masses of 1.045 ± 0.031 M {sub ?} and 0.408 ± 0.066 M {sub ?} and 38.10 ± 2.81 mas for ? Cephei.

  16. EVOLUTION OF THE WATER MASER EXPANDING SHELL IN W75N VLA 2

    SciTech Connect (OSTI)

    Kim, Jeong-Sook; Kim, Sang Joon [School of Space Science, Kyunghee University, Seocheon-dong, Giheung-si, Gyeonggi-do, 446-701 (Korea, Republic of)] [School of Space Science, Kyunghee University, Seocheon-dong, Giheung-si, Gyeonggi-do, 446-701 (Korea, Republic of); Kim, Soon-Wook [Korea Astronomy and Space Science Institute, 776 Daedeokdaero, Yuseong, Daejeon 305-348 (Korea, Republic of)] [Korea Astronomy and Space Science Institute, 776 Daedeokdaero, Yuseong, Daejeon 305-348 (Korea, Republic of); Kurayama, Tomoharu [Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Kagoshima 890-0065 (Japan)] [Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Kagoshima 890-0065 (Japan); Honma, Mareki [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Sasao, Tesuo [Yaeyama Star Club, Ookawa, Ishigaki, Okinawa 904-0022 (Japan)] [Yaeyama Star Club, Ookawa, Ishigaki, Okinawa 904-0022 (Japan); Surcis, Gabriele [Joint Institute for VLBI in Europe, Postbus 2, 7990 AA Dwingeloo (Netherlands)] [Joint Institute for VLBI in Europe, Postbus 2, 7990 AA Dwingeloo (Netherlands); Canto, Jorge [Instituto de Astronomia (UNAM), Apartado 70-264, 04510 Mexico D. F. (Mexico)] [Instituto de Astronomia (UNAM), Apartado 70-264, 04510 Mexico D. F. (Mexico); Torrelles, Jose M., E-mail: evony@kasi.re.kr, E-mail: skim@kasi.re.kr [Instituto de Ciencias del Espacio (CSIC)-UB/IEEC, Universitat de Barcelona, Marti i Franques 1, E-08028 Barcelona (Spain)

    2013-04-10

    We present Very Long Baseline Interferometry (VLBI) observations of 22 GHz H{sub 2}O masers in the high-mass star-forming region of W75N, carried out with VLBI Exploration of Radio Astrometry (VERA) for three epochs in 2007 with an angular resolution of {approx}1 mas. We detected H{sub 2}O maser emission toward the radio jet in VLA 1 and the expanding shell-like structure in VLA 2. The spatial distribution of the H{sub 2}O masers detected with VERA and measured proper motions around VLA 1 and VLA 2 are similar to those found with previous VLBI observations in epochs 1999 and 2005, with the masers in VLA 1 mainly distributed along a linear structure parallel to the radio jet and, on the other hand, forming a shell-like structure around VLA 2. We have made elliptical fits to the VLA 2 H{sub 2}O maser shell-like structure observed in the different epochs (1999, 2005, and 2007), and found that the shell is still expanding eight years after its discovery. From the difference in the size of the semi-major axes of the fitted ellipses in epochs 1999 ({approx_equal}71 {+-} 1 mas), 2005 ({approx_equal}97 {+-} 3 mas), and 2007 ({approx_equal}111 {+-} 1 mas), we estimate an average expanding velocity of {approx}5 mas yr{sup -1}, similar to the proper motions measured in the individual H{sub 2}O maser features. A kinematic age of {approx}20 yr is derived for this structure. In addition, our VERA observations indicate an increase in the ellipticity of the expanding shell around VLA 2 from epochs 1999 to 2007. In fact, the elliptical fit of the VERA data shows a ratio of the minor and major axes of {approx}0.6, in contrast with an almost circular shape for the shell detected in 1999 and 2005 (b/a {approx} 0.9). This suggests that we are probably observing the formation of a jet-driven H{sub 2}O maser structure in VLA2, evolving from a non-collimated pulsed-outflow event during the first stages of evolution of a massive young stellar object (YSO). This may support predictions made earlier by other authors on this issue, consistent with recent magnetohydrodynamical simulations. We discuss possible implications of our results in the study of the first stages of evolution of massive YSOs.

  17. Asymmetric Surface Brightness Distribution of Altair Observed with the Navy Prototype Optical Interferometer

    E-Print Network [OSTI]

    Naoko Ohishi; Tyler E. Nordgren; Donald J. Hutter

    2004-05-16

    An asymmetric surface brightness distribution of the rapidly rotating A7IV-V star, Altair, has been measured by the Navy Prototype Optical Interferometer (NPOI). The observations were recorded simultaneously using a triangle of three long baselines of 30m, 37m, and 64m, on 19 spectral channels, covering the wavelength range of 520nm to 850nm. The outstanding characteristics of these observations are (a) high resolution with the minimum fringe spacing of 1.7mas, easily resolving the 3-milliarcsecond (mas) stellar disk, and (b) the measurement of closure phase which is a sensitive indicator to the asymmetry of the brightness distribution of the source. Uniform disk diameters fit to the measured squared visibility amplitudes confirms the Altair's oblate shape due to its rapid rotation. The measured observables of Altair showed two features which are inconsistent with both the uniform-disk and limb-darkened disk models, while the measured observable of the comparison star, Vega, are consistent with the limb-darkened disk model. The first feature is that measured squared visibility amplitudes at the first minimum do not reach 0.0 but rather remain at about 0.02, indicating the existence of a small bright region on the stellar disk. The other is that the measured closure phases show non-zero/180 degrees at all spectral channels, which requires an asymmetric surface brightness distribution. We fitted the measured observables to a model with a bright spot on a limb-darkened disk and found the observations are well reproduced by a bright spot, which has relative intensity of 4.7%, on a 3.38 mas limb-darkened stellar disk. Rapid rotation of Altair indicates that this bright region is a pole, which is brighter than other part of the star owing to gravity darkening.

  18. Radio observations of the gamma-ray quasar 0528+134: Superluminal motion and an extreme scattering event

    E-Print Network [OSTI]

    M. Pohl; W. Reich; T. P. Krichbaum; K. Standke; S. Britzen; H. P. Reuter; P. Reich; R. Schlickeiser; R. L. Fiedler; E. B. Waltman; F. D. Ghigo; K. J. Johnston

    1995-03-22

    We report on multifrequency radio observations made with the Effelsberg 100-m telescope, the IRAM 30-m telescope and the Green Bank Interferometer between 1992 and 1994 of the $\\gamma$-ray quasar 0528+134. We present a new VLBI based map of 0518+134 at 22 GHz with sub-mas angular resolution observed in November 1992, which shows a one-sided core jet structure of $\\sim$ 5 mas length. One component, seen also previously at 8.4 GHz & 22 GHz, shows apparent superluminal motion with $\\beta_{app}$=4.4$\\pm$1.7. In summer 1993 we observed a major outburst at all frequencies higher than a few GHz, which peaked a few months after a strong outburst in high energy $\\gamma$-rays and showed the canonical time evolution of a cooling and/or expanding electron distribution. Our data indicate that the outburst in the EGRET range originated very close to the central object of the AGN and that a remnant of this outburst moved further outward in the jet until it became optically thin at radio frequencies after a few months. During the flare in July 1993 we observed with the Effelsberg 100-m telescope an unusually strong decrease of the flux density by about 50% at 4.75 GHz and 10.55 GHz and slightly less at 2.695 GHz. This behaviour is also seen in the monitoring data at 2.25 GHz and 8.3 GHz taken with the Green Bank Interferometer (NRL-GBI). An extreme scattering event by a small dense plasma cloud in the line of sight is able to match the observed time lag in the lightcurves if we take into account the mas-structure of the source and different spectra of the components on the basis of their brightness in the VLBI maps.

  19. Comparison of moment-closure approximations for stochastic chemical kinetics

    E-Print Network [OSTI]

    David Schnoerr; Guido Sanguinetti; Ramon Grima

    2015-08-07

    In recent years moment-closure approximations (MA) of the chemical master equation have become a popular method for the study of stochastic effects in chemical reaction systems. Several different MA methods have been proposed and applied in the literature, but it remains unclear how they perform with respect to each other. In this paper we study the normal, Poisson, log-normal and central-moment-neglect MAs by applying them to understand the stochastic properties of chemical systems whose deterministic rate equations show the properties of bistability, ultrasensitivity and oscillatory behaviour. Our results suggest that the normal MA is favourable over the other studied MAs. In particular we found that (i) the size of the region of parameter space where a closure gives physically meaningful results, e.g. positive mean and variance, is considerably larger for the normal closure than for the other three closures; (ii) the accuracy of the predictions of the four closures (relative to simulations using the stochastic simulation algorithm) is comparable in those regions of parameter space where all closures give physically meaningful results; (iii) the Poisson and log-normal MAs are not uniquely defined for systems involving conservation laws in molecule numbers. We also describe the new software package MOCA which enables the automated numerical analysis of various MA methods in a graphical user interface and which was used to perform the comparative analysis presented in this paper. MOCA allows the user to develop novel closure methods and can treat polynomial, non-polynomial, as well as time-dependent propensity functions, thus being applicable to virtually any chemical reaction system.

  20. Tailoring surface properties and structure of layered double hydroxides using silanes with different number of functional groups

    SciTech Connect (OSTI)

    Tao, Qi; He, Hongping; Li, Tian; Frost, Ray L.; Zhang, Dan; He, Zisen

    2014-05-01

    Four silanes, trimethylchlorosilane (TMCS), dimethyldiethoxylsilane (DMDES), 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS), were adopted to graft layered double hydroxides (LDH) via an induced hydrolysis silylation method (IHS). Fourier transform infrared spectra (FTIR) and {sup 29}Si MAS nuclear magnetic resonance spectra ({sup 29}Si MAS NMR) indicated that APTES and TEOS can be grafted onto LDH surfaces via condensation with hydroxyl groups of LDH, while TMCS and DMDES could only be adsorbed on the LDH surface with a small quantity. A combination of X-ray diffraction patterns (XRD) and {sup 29}Si MAS NMR spectra showed that silanes were exclusively present in the external surface and had little influence on the long range order of LDH. The surfactant intercalation experiment indicated that the adsorbed and/or grafted silane could not fix the interlamellar spacing of the LDH. However, they will form crosslink between the particles and affect the further surfactant intercalation in the silylated samples. The replacement of water by ethanol in the tactoids and/or aggregations and the polysiloxane oligomers formed during silylation procedure can dramatically increase the value of BET surface area (S{sub BET}) and total pore volumes (V{sub p}) of the products. - Graphical abstract: The replacement of water by ethanol in the tactoids and aggregations of LDHs, and the polysiloxane oligomers formed during silylation process can dramatically increase the BET surface area (S{sub BET}) and the total pore volume (V{sub p}) of the silylated products. - Highlights: • Silanes with multifunctional groups were grafted onto LDH surface in C{sub 2}H{sub 5}OH medium. • The number of hydrolysable groups in silanes affects the structure of grafted LDH. • Replacement of H{sub 2}O by C{sub 2}H{sub 5}OH in aggregations increases S{sub BET} and V{sub p} of grafted LDH. • Polysiloxane oligomers contribute to the increase of S{sub BET} and V{sub p} of grafted LDH.

  1. RELATIVISTIC JETS IN THE RADIO REFERENCE FRAME IMAGE DATABASE. II. BLAZAR JET ACCELERATIONS FROM THE FIRST 10 YEARS OF DATA (1994-2003)

    SciTech Connect (OSTI)

    Piner, B. G.; Marvin, C. J.; Arenson, J. G.; Pushkarev, A. B.; Fey, A. L.

    2012-10-20

    We analyze blazar jet apparent speeds and accelerations from the RDV series of astrometric and geodetic very long baseline interferometry (VLBI) experiments. From these experiments, we have produced and analyzed 2753 global VLBI images of 68 sources at 8 GHz with a median beam size of 0.9 milliarcseconds (mas) and a median of 43 epochs per source. From this sample, we analyze the motions of 225 jet components in 66 sources. The distribution of the fastest measured apparent speed in each source has a median of 8.3c and a maximum of 44c. Sources in the 2FGL Fermi LAT catalog display higher apparent speeds than those that have not been detected. On average, components farther from the core in a given source have significantly higher apparent speeds than components closer to the core; for example, for a typical source, components at {approx}3 mas from the core ({approx}15 pc projected at z {approx} 0.5) have apparent speeds about 50% higher than those of components at {approx}1 mas from the core ({approx}5 pc projected at z {approx} 0.5). We measure accelerations of components in orthogonal directions parallel and perpendicular to their average velocity vector. Parallel accelerations have significantly larger magnitudes than perpendicular accelerations, implying that observed accelerations are predominantly due to changes in the Lorentz factor (bulk or pattern) rather than projection effects from jet bending. Positive parallel accelerations are significantly more common than negative ones, so the Lorentz factor (bulk or pattern) tends to increase on the scales observed here. Observed parallel accelerations correspond to modest source frame increases in the bulk or pattern Lorentz factor.

  2. Radio-optical reference frame link using the U.S. Naval observatory astrograph and deep CCD imaging

    SciTech Connect (OSTI)

    Zacharias, N.; Zacharias, M. I.

    2014-05-01

    Between 1997 and 2004 several observing runs were conducted, mainly with the CTIO 0.9 m, to image International Celestial Reference Frame (ICRF) counterparts (mostly QSOs) in order to determine accurate optical positions. Contemporary to these deep CCD images, the same fields were observed with the U.S. Naval Observatory astrograph in the same bandpass. They provide accurate positions on the Hipparcos/Tycho-2 system for stars in the 10-16 mag range used as reference stars for the deep CCD imaging data. Here we present final optical position results of 413 sources based on reference stars obtained by dedicated astrograph observations that were reduced following two different procedures. These optical positions are compared to radio very long baseline interferometry positions. The current optical system is not perfectly aligned to the ICRF radio system with rigid body rotation angles of 3-5 mas (= 3? level) found between them for all three axes. Furthermore, statistically, the optical-radio position differences are found to exceed the total, combined, known errors in the observations. Systematic errors in the optical reference star positions and physical offsets between the centers of optical and radio emissions are both identified as likely causes. A detrimental, astrophysical, random noise component is postulated to be on about the 10 mas level. If confirmed by future observations, this could severely limit the Gaia to ICRF reference frame alignment accuracy to an error of about 0.5 mas per coordinate axis with the current number of sources envisioned to provide the link. A list of 36 ICRF sources without the detection of an optical counterpart to a limiting magnitude of about R = 22 is provided as well.

  3. VERY LONG BASELINE INTERFEROMETRY MEASURED PROPER MOTION AND PARALLAX OF THE ?-RAY MILLISECOND PULSAR PSR J0218+4232

    SciTech Connect (OSTI)

    Du, Yuanjie; Chen, Ding; Yang, Jun; Campbell, Robert M.; Janssen, Gemma; Stappers, Ben

    2014-02-20

    PSR J0218+4232 is a millisecond pulsar (MSP) with a flux density ?0.9 mJy at 1.4 GHz. It is very bright in the high-energy X-ray and ?-ray domains. We conducted an astrometric program using the European VLBI Network (EVN) at 1.6 GHz to measure its proper motion and parallax. A model-independent distance would also help constrain its ?-ray luminosity. We achieved a detection of signal-to-noise ratio S/N >37 for the weak pulsar in all five epochs. Using an extragalactic radio source lying 20 arcmin away from the pulsar, we estimate the pulsar's proper motion to be ?{sub ?}cos ? = 5.35 ± 0.05 mas yr{sup –1} and ?{sub ?} = –3.74 ± 0.12 mas yr{sup –1}, and a parallax of ? = 0.16 ± 0.09 mas. The very long baseline interferometry (VLBI) proper motion has significantly improved upon the estimates from long-term pulsar timing observations. The VLBI parallax provides the first model-independent distance constraints: d=6.3{sub ?2.3}{sup +8.0} kpc, with a corresponding 3? lower-limit of d = 2.3 kpc. This is the first pulsar trigonometric parallax measurement based solely on EVN observations. Using the derived distance, we believe that PSR J0218+4232 is the most energetic ?-ray MSP known to date. The luminosity based on even our 3? lower-limit distance is high enough to pose challenges to the conventional outer gap and slot gap models.

  4. SU-E-I-95: Personalized Radiography Technical Parameters for Each Patient and Exam

    SciTech Connect (OSTI)

    Soares, F; Camozzato, T; Kahl, G; Soares, A; Zottis, A [Instituto Federal de Santa Catarina, Florianopolis (Brazil)

    2014-06-01

    Purpose: To determine exact electrical parameters (kV, mAs) a radiological technologist shall use taking account the exam and patient's structure, with guarantee of minimum dose and adequate quality image. Methods: A patient's absorbed dose equation was developed by means of Entrance Skin Dose (ESD), irradiated area and patient width for specific anatomy. ESD is calculated from a developed equation, where entrance surface air-KERMA and backscatter factor are included, with air-to-skin coefficient conversion. We developed specific Lambert-Beer attenuation equations derived from mass energy-absorption coefficients data for skin, fat, and muscle and bone as one tissue. Anatomy tissue thickness distribution at central X-ray location in anteroposterior incidence for hand and chest, was estimate by discounting constant skin and bone thickness from patient measured width, assuming the result as muscle and fat. A clinical research at a big hospital were executed when real parameters (kV, mAs, filtration, ripple) used by technologists were combined with the image quality and patient's data: anatomy width, height and weight. A correlation among the best images acquired and electrical parameters used were confronted with patient's data and dose estimation. The best combinations were used as gold standards. Results: For each anatomy, two equations were developed to calculate voltage (kV) and exposure (mAs) to reproduce and interpolate the gold standards. Patient is measured and data are input into equations, giving radiological technologists the right set of electrical parameters for that specific exam. Conclusion: This work indicates that radiological technologist can personalize the exact electrical parameters for each patient exam, instead of using standard values. It also guarantee that patients under or over-sized measures will receive the right dose for the best image. It will stop wrong empiric adjusts technologists do when examining a non-standard patient and reduce probability of radiography retaken because of over or under exposition.

  5. 4000 2000 0 DE413+PLU017

    E-Print Network [OSTI]

    Young, Leslie A.

    SAAO 4000 2000 0 ­2000 ­4000 E (km) ­4000 ­2000 0 2000 4000 N (km) DE­413 Plu017 + ( 0.0, 0.0) mas:40:07 23:51:48 Mean 23:45:58 #12; SAAO 4000 2000 0 ­2000 ­4000 E (km) ­4000 ­2000 0 2000 4000 N (km) DE­413:39:20 23:44:25 23:36:32 23:49:12 Mean 23:42:52 23:41:25 23:44:19 #12; SAAO 4000 2000 0 ­2000 ­4000 E (km

  6. SU-F-18C-06: Prospective Patient Evaluation of Iterative Reconstruction in Radiation Oncology

    SciTech Connect (OSTI)

    Price, R; Vance, S; Cattaneo, R; Schultz, L; Elshaikh, M; Chetty, I; Glide-Hurst, C

    2014-06-15

    Purpose: This work incorporates iterative reconstruction (IR) into a dose reduction study to characterize image quality metrics, delineation, and dosimetric assessment, with the goal of reducing imaging dose in Radiation Oncology. Methods: Three-dimensional noise power spectrum (NPS) analysis characterized noise magnitude/texture (120 kVp, 50–200 mAs, IR levels 1–6 yielding noise reduction of 0.89–0.55 compared to filtered backprojection (FBP)). Task-specific Modulation Transfer Functions (MTFtask) were characterized across varied subject contrasts. A prospective dose reduction study (500 to 150 mAs) was conducted for 12 patients (43 inter-fraction CTs) for high-dose rate brachytherapy. Three physicians performed qualitative image assessment between full-dose FBP (FD-FBP, 500 mAs), low-dose FBP (LD-FBP, 150–250 mAs), and low-dose IRL5-6 (LD-IR) scans for image noise, cuff/bladder interface detectability, spatial resolution, texture, and segmentation confidence. Comparisons between LD-FBP and LD-IR were conducted for the following metrics: delineation (bladder and rectum evaluated via overlap indices (OI) and Dice similarity coefficients (DSC)), noise, boundary changes, dose calculation, and digitally reconstructed radiographs (DRRs). Results: NPS showed ?50% reduction in noise magnitude and ?0.1 1/mm spatial frequency shift with IRL6. The largest MTFtask decrease between FBP and IR was 0.08 A.U. Qualitative patient image evaluation revealed LD-IR was equivalent or slightly worse than FD-FBP, and superior to LD-FBP for all metrics except low contrast interface and texture. The largest CT number discrepancy from FBP occurred at a bone/tissue interface using IRL6 (?1.2 ± 4.9 HU (range: ?17.6 – 12.5 HU)). No significant contour differences (OIs and DSCs = 0.85 – 0.95) and dose calculation discrepancy (<0.02%) were observed. DRRs preserved anatomical detail and demonstrated <2% difference in intensity between LD-FBP and LD-IRL6. Conclusion: While phantom analysis showed slight noise texture differences with IR, patient results revealed that image quality, contouring ability, and dosimetric parameters were not adversely affected, thus support integrating IR into treatment planning. Research supported in part by a grant from Philips HealthCare.

  7. Schottky and other electrical phenomena in polyethylene crystals 

    E-Print Network [OSTI]

    Stoltz, Richard Joseph

    1970-01-01

    fields to 2&c applie&1 ac ros s the alumi? num-polyethylene-aluminum sandwich (I ig 7). Each step of sample preparation is photographed to allow determination of the area, of the crystal between the electrodes as well as to provide visual evidence... thickness can be calculated. 2 P i y[ if'yLf="I= ? ? --~ GLASS SLI!)i- ll; '/41. '-/~ / L~Z 1, ' / / //y. '. ', , j; / / / IAICA ~ ALIIlIIfIIIlI SUBSTRATF. Technique oi mas1 in' crystals. Top view. ALUfll NUi'i ALUf'l I 'JUIAI z 'J~ GLASS 9'ig. 7...

  8. URAT: astrometric requirements and design history

    E-Print Network [OSTI]

    N. Zacharias; U. Laux; A. Rakich; H. Epps

    2006-06-08

    The U.S. Naval Observatory Robotic Astrometric Telescope (URAT) project aims at a highly accurate (5 mas), ground-based, all-sky survey. Requirements are presented for the optics and telescope for this 0.85 m aperture, 4.5 degree diameter field-of-view, specialized instrument, which are close to the capability of the industry. The history of the design process is presented as well as astrometric performance evaluations of the toleranced, optical design, with expected wavefront errors included.

  9. Variable-temperature solid-state NMR studies of iron(II) and iron(III) complexes 

    E-Print Network [OSTI]

    Shepard, Patricia Arlene

    1989-01-01

    of paramagnetic impurities to enhance H NMR relaxation rates in solid-state biomolecules was shown to be an effective method for obtaining C spectra using cross-polarization (CP) and magic angle spinning (MAS) (vide infra). In 1983 Bryant et al. published...-lattice relaxation measurements for C nuclei on neighboring low- spin Zn(II) complexes should provide fundamental information concerning the effects of randomly-distributed paramagnetic sites on C nuclear relaxation behavior. According to VanderHart, if the Tl...

  10. VLBI polarimetric observations of 3C147

    E-Print Network [OSTI]

    A. Rossetti; F. Mantovani; D. Dallacasa

    2004-12-29

    We present multi-frequency VLBI observations of the Compact Steep-spectrum Quasar 3C147 (0538+498) made with the VLBA at the four frequencies in the available 5 GHz band and at 8.4 GHz (still under analysis), from which we derived millarcsecond-resolution images of the total intensity, polarization, and rotation measure distributions. The source shows a core-jet structure, with a compact feature and a jet, extending about 200 mas to the South-West. We detect polarized emission in two bright features in the inner jet; the rotation measure of this features (aprox -1630 rad m(-2), aprox -540 rad m(-2)).

  11. HST revisits the proper motion of PSR B0656+14

    E-Print Network [OSTI]

    R. P. Mignani; A. DeLuca; P. A. Caraveo

    2000-05-09

    We report the first successful measurement (with HST/WFPC2) of a significant proper motion for a V~ 25 object which we had proposed as the optical counterpart of the radio pulsar PSR B0656+14. The yearly displacement of 43+/- 2 mas is highly significant and, while in agreement with early, rougher, radio measurements, stands out for its vastly improved accuracy. Together with the report of a possible optical pulsation (Shearer et al. 1998), we regard this result as the final proof of the optical identification of PSR B0656+14.

  12. Packing a Safe School Lunch (Spanish) 

    E-Print Network [OSTI]

    Van Laanen, Peggy

    2001-10-22

    para causar enfemedad. Algunos alimentos deben mantenerse fr?os (a 40 gra- dos F o menos) o calientes (a 140 grados F o mas). Estos son alimentos perecederos tales como carne, aves, mariscos, huevos y productos l?cteos (incluyen- do el yogurt). Lo m...?s importante para preparar una comida sana, es mantener fr?os los alimentos fr?os y caliente los alimentos calientes y mantener todo limpio. A continuaci?n, el por qu? y el c?mo. Para reproducirse, las bacterias que causan enferme- dad alimenticia necesitan...

  13. Hydroxyproline Ring Pucker Causes Frustration of Helix Parameters in the Collagen Triple Helix

    E-Print Network [OSTI]

    Chow, W. Ying; Bihan, Dominique; Forman, Chris J.; Slatter, David A.; Reid, David G.; Wales, David J.; Farndale, Richard W.; Duer, Melinda J.

    2015-01-01

    -time of flight (MALDI-TOF) mass spectrometry, then lyophilised. Solid-state NMR All ssNMR spectra were recorded on a 9.4 Tesla Bruker Avance I NMR spectrometer, operating at frequencies of 400 MHz (1H) and 100 MHz (13C). Magic angle spinning (MAS) frequency... .38 The initial co-ordinates and topology for (POG)12 were generated from PDB 1V7H 9 and modified to give (PPG)12. Full details can be found in Section S2, Supplementary Information. Differential Scanning Calorimetry (DSC) DSC was performed using a...

  14. Matematica Discreta Segundo de Ingenieria Informatica UAM

    E-Print Network [OSTI]

    Fernández Gallardo, Pablo

    . Construir ´arboles abarcadores de los siguientes grafos mediante los algoritmos BA y BP. 12 3 8 6 1 2 4 5 7 algoritmos de Prim y de Kruskaal. v11 v2 v7 v5 v12 v1 v3 v4 v6 v9 v8 v10 1 2 13 2 7 4 1 2 5 1 7 2 3 9 v11 v2 abarcadores que calculan la ruta m´as corta desde los v´ertices v1 y v3 usando el algoritmo de Dijkstra. v11 v

  15. 2H and 27Al Solid-State NMR Study of the Local Environments in Aldoped 2-Line Ferrihydrite, Goethite, and Lepidocrocite

    E-Print Network [OSTI]

    Kim, Jongsik; Ilott, Andrew J.; Middlemiss, Derek S.; Chernova, Natasha A.; Pinney, Nathan; Morgan, Dane; Grey, Clare P.

    2015-05-13

    -doped goethite. Two sets of samples were prepared, labeled sets A and B, which differ in the temperature used in their syntheses. Set A, 70 ?C synthesis: to synthesize a series of goethite with 0, 6, 13, and 27 mol % Al substitution (labeled GA0, GA6, GA13... significant fraction occupies the surface sites. The lower temperature synthesis of GB0 (48 vs. 70 ºC) may also promote more vacancy formation. Figure 12. 2H MAS NMR spectra of Al-doped goethite samples, (a) GA0, (b) GA13, and (c) GA27, acquired at 433 K...

  16. Exame de Mec^anica Geometrica Jose Natario

    E-Print Network [OSTI]

    Natário, José

    = r sen sen z = r cos e que a energia cin´etica de uma part´icula de massa m em R3 ´e dada por¸c~ao do seu planeta a 60% da velocidade da luz. Em desespero de causa, decide-se instalar um motor¸c~ao demora 1 ano, mas o novo motor funciona na perfei¸c~ao. A Enterprise parte no encal¸co do espi~ao e

  17. The Soils of Texas. 

    E-Print Network [OSTI]

    Carter, W. T. (William Thomas)

    1931-01-01

    ., Horticulturist L. E. BROOKS, B. S., Horticulturist RANGE ANIMAL HUSBANDRY: J. M. JoNES, A. M., Chief B L. WARWICK, Ph.D., Breedin!} Investigations S. P. DAVIS, Wool Grader ENTOMvLOGY: F. L. TnoMAS, Ph. D., Chief; State Entflmologist H. J. REINH.,RD, B. S... AGRICULTURAL ENGINEimiNG: I I P. SMITH, M.S., Chief MAIN STATION FARM: G . T. McNEss, Superintendent APICULTURE (San Antonio): H. B. PARKS, B. S., Chief A. H. ALEX, B. S., Queen Breeder FEED CONTROL SERVICE: F D . FuLLER, M. S., Chief JAMES Su...

  18. A market study of the frozen fruit and vegetable industry 

    E-Print Network [OSTI]

    Bradley, James Russell

    1954-01-01

    of vcapiug tldelaweaoe usy bo frosea st tbs seas ties betssoa giffuroat aAs af pIstoo. Ths oabisst is iaeabtc4 oo tbst tbs freoasr ~ bs operated ia s ream of ardisorp toape?atare. Sash froosor ia aslfWoatodl0od ead ycrtsble? sad as' be arced fboa olN p... frooaiag Mas varies viih tbs thiohaess of the pcahage? ea we11 ss tbs hind of yndsA, Tee iaoh4hieh ~s ef f?aits ssd tegstsbles roqaire shoat two home for Aeoaiag. This asthod of f?ossfag is oIHorod bp' INHlersl pstsate ead ie assd cecelusitog Q ths...

  19. Abundance and distribution of the western Gulf stone crab (Menippe adina) in Galveston Bay, Texas 

    E-Print Network [OSTI]

    Boslet, Jane Murray

    1989-01-01

    I BUNDANCE AND DI STRISUT . ON OF THE WESTERN GULF STOiuE CRAB LilFNIL'PC l', Diijil) IN GALVESTON BAY TEXAS Thesis JALXE iiURRAY HOSLET SuL&mitted to th= Office of Graduate Studies of Texa Aai1 University in :. a- Dial fulfullment... of the requirements for the deqree of MAS'I ~ R OI" SCIENCE May 19B9 Major subject: Wildlife and Fisheries Sciences ABUNDANCE AND DISTRIBUTION OF THE WESTERN GULF STONE CRAB (NENIPPE ADINA) IN GALVESTON BAY, TEXAS A Thesis by JANE MURRAY BOSLET Approved...

  20. The Culture of Cigar Leaf Tobacco in Texas. 

    E-Print Network [OSTI]

    Olson, Otto

    1912-01-01

    , and the ~ good, sound leaves as wrappers. There is at present a decided de- mand for these wrappers, principally because of the fact that they closely resemble the imported Cuban wrapper. The veins of the leaf are small so that the entire leaf can be used... veins" on the leaves, and the average yield was 1000 pounds per acre. As the average cost of prodncing this class of tobacco is aho~it Q cents per pound, the margin of profit mas not very great. This low price, in connection with the high prices paid...

  1. PROCESSING METHOD EFFECT ON SUN DIAMETER MEASUREMENT WITH CCD SOLAR ASTROLABE

    SciTech Connect (OSTI)

    Djafer, Djelloul; Irbah, Abdenour E-mail: abdenour.irbah@latmos.ipsl.fr

    2012-05-01

    Photometric Sun diameter measurement is based on the calculation of the inflection point of the solar limb. In ground measurement, this point is located at a position on the solar limb where the signal-to-noise ratio is very high, which necessitates the appropriate filtering techniques to eliminate the noise while preserving its position. In this paper, we compare the filtering method currently in use to process the CCD solar astrolabe data, the FFTD method widely used, with a different method that we propose. Using the acquired data from the CCD astrolabe at Calern, France during 1997, we can obtain a mean difference of 130 mas in the measured radii.

  2. Parental care masks a density-dependent shift from cooperation to competition among burying beetle larvae

    E-Print Network [OSTI]

    Schrader, Matthew; Jarrett, Benjamin J. M.; Kilner, Rebecca M.

    2015-03-21

    . Kolliker, eds. The evolution of parental care. Oxford Univ. Press, Oxford, U.K. Marti, C. D. 1989. Food sharing by sibling common barn-owls. Wilson Bull. 101:132–134. Mas, F., and M. Ko¨lliker. 2008. Maternal care and offspring begging in social insects... (Tyto alba) nestlings have been documented feeding one another (Marti 1989) and there is evidence that barn swallow (Hirundo rustica) nestlings moder- ate their selfishness when their siblings have been food deprived (Romano et al. 2012). Although...

  3. A new species of Eufriesea from Jalisco, Mexico, with a key to Mexican species of the genus (Hymenoptera: Apidae)

    E-Print Network [OSTI]

    Ayala, Ricardo; Engel, Michael S.

    2008-01-01

    verdoso oscuro o purpura oscuro; ala anterior con la celula medial (M), no mas oscura que el resto del ala E. mexicana (MOCSÄRY) Cabeza y törax oscuro; alas anteriores con la celula medial oscurecida respecto al resto DEL ALA E. surinamensis (LINNAEUS... color pardo o pardo claro de la mitad anterior del mesoescuto 12 12(11) Ala anterior oscurecida, con la celula medial (M) de color similar que el resto del ala; S8 prolongandose en una sola proyecciön apical aguda, en vista lateral E. mexicana...

  4. Characterization of polyxylylenes with solid state {sup 13}C nuclear magnetic resonance spectroscopy

    SciTech Connect (OSTI)

    Schneider, D.A.; Loy, D.A.; Assink, R.A. [Sandia National Labs., Albuquerque, NM (United States)] [and others

    1996-10-01

    Polyxylylenes are an important class of thermoplastics that are readily prepared by thermolysis of [2.2]paracyclophane or xylene precursors to afford xylylene monomers that condense and polymerize on solid surfaces to give polymer films. As most polyxylylenes are insoluble due to a high degree of crystallinity, characterization by solid state nuclear magnetic resonance spectroscopic techniques is necessary. In this paper we describe the preparation of polyxylylene, poly-2-ethylxylylene, poly-2-chloroxylylene, poly-2, 3-dichloroxylylene, and poly({alpha}, {alpha}, {alpha}{prime}, {alpha}{prime}-tetrafluoroxylylene) and their characterization using solid state {sup 13}C Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance (CP MAS NMR) spectroscopy.

  5. Supplement 18, Part 7, Parasite-Subject Catalogue: Hosts 

    E-Print Network [OSTI]

    Edwards, Shirley J.; Kirby, Margie D.; Crawley, Lila R.; Rayburn, Jane D.; Shaw, Judith H.; Walker, Martha L.

    1974-01-01

    STATION A. B. CONNER, XRECTOR COLLEGE STATION, BKAZOS COUNTY, TEXAS BULLETIN NO. 403 OCTOBER, 1929 DIVISION OF CHEMISTRY COMMERCIAL FERTILIZERS IN 1928-29 AND THEIR USES AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS T. 0. WALTON, President STATION... ............................................................. 27 BULLETIN NO. 403 OCTOBER, 1929 COMMERCIAL FERTILIZERS IN 1928-29 AND THEIR USES G. S. FRAPS AND S. E. ASBURY A fertilizer law was first passed in T~X~S in 1899. It mas revised and amended in 1911. The results of the fertilizer inspection have...

  6. An Investigation of the Absolute Proper Motions of the SCUSS Catalog

    E-Print Network [OSTI]

    Peng, Xiyan; Wu, Zhenyu; Ma, Jun; Du, Cuihua; Zhou, Xu; Yu, Yong; Tang, Zhenghong; Jiang, Zhaoji; Zou, Hu; Fan, Zhou; Fan, Xiaohui; Smith, Martin C; Jiang, Linhua; Jing, Yipeng; Lattanzi, Mario G; Mclean, Brian J; Lesser, Michael; Nie, Jundan; Shen, Shiyin; Wang, Jiali; Zhang, Tianmeng; Zhou, Zhimin; Wang, Songhu

    2015-01-01

    Absolute proper motions for $\\sim$ 7.7 million objects were derived based on data from the South Galactic Cap u-band Sky Survey (SCUSS) and astrometric data derived from uncompressed Digitized Sky Surveys that the Space Telescope Science Institute (STScI) created from the Palomar and UK Schmidt survey plates. We put a great deal of effort into correcting the position-, magnitude-, and color-dependent systematic errors in the derived absolute proper motions. The spectroscopically confirmed quasars were used to test the internal systematic and random error of the proper motions. The systematic errors of the overall proper motions in the SCUSS catalog are estimated as -0.08 and -0.06 mas/yr for {\\mu}{\\alpha} cos {\\delta} and {\\mu}{\\delta}, respectively. The random errors of the proper motions in the SCUSS catalog are estimated independently as 4.2 and 4.4 mas/yr for {\\mu}{\\alpha} cos {\\delta} and {\\mu}{\\delta}. There are no obvious position-, magnitude-, and color-dependent systematic errors of the SCUSS proper ...

  7. Present status of JEFF-3.1 validation for fast reactors using the ERANOS-2.1 code system

    SciTech Connect (OSTI)

    Tommasi, J.; Ruggieri, J. M.; Lebrat, J. F.; Plisson-Rieunier, D.; Sublet, J. C. [CEA-Cadarache, DEN/DER/SPRC, 13108 Saint Paul Lez Durance (France)

    2006-07-01

    The latest release (2.1) of the ERANOS code system, using JEF-2.2, JEFF-3.1 and ENDF/B-VI r8 multigroup cross-section libraries is currently being validated on fast reactor critical experiments at CEA-Cadarache (France). This paper briefly presents the library effect studies and the detailed best-estimate validation studies performed up to now as part of the validation process. The library effect studies are performed over a wide range of experimental configurations, using simple model and method options. They yield global trends about the shift from JEF-2.2 to JEFF-3.1 cross-section libraries, that can be related to individual sensitivities and cross-section changes. The more detailed, best-estimate, calculations have been performed up to now over three experimental configurations carried out in the MASURCA critical facility at CEA-Cadarache: two cores with a softened spectrum due to large amounts of graphite (MAS1A' and MAS1B), and a core representative of sodium-cooled fast reactors (CIRANO ZONA2A). Calculated values have been compared to measurements, and discrepancies analyzed in detail using perturbation theory. Values calculated with JEFF-3.1 were found to be within 3 standard deviations of the measured values, and at least of the same quality as the JEF-2.2 based results. (authors)

  8. Final binary star results from the ESO VLT Lunar occultations program

    SciTech Connect (OSTI)

    Richichi, A.; Fors, O.; Cusano, F.; Ivanov, V. D.

    2014-03-01

    We report on 13 subarcsecond binaries, detected by means of lunar occultations in the near-infrared at the ESO Very Large Telescope (VLT). They are all first-time detections except for the visual binary HD 158122, which we resolved for the first time in the near-infrared. The primaries have magnitudes in the range K = 4.5-10.0, and companions in the range K = 6.8-11.1. The magnitude differences have a median value of 2.4, with the largest being 4.6. The projected separations are in the range of 4-168 mas, with a median of 13 mas. We discuss and compare our results with the available literature. With this paper, we conclude the mining for binary star detections in the 1226 occultations recorded at the VLT with the ISAAC instrument. We expect that the majority of these binaries may be unresolvable by adaptive optics on current telescopes, and they might be challenging for long-baseline interferometry. However, they constitute an interesting sample for future larger telescopes and for astrometric missions such as GAIA.

  9. Bright Star Astrometry with URAT

    E-Print Network [OSTI]

    Zacharias, Norbert

    2015-01-01

    The U.S. Naval Observatory Robotic Astrometric Telescope (URAT) is observing the northern sky since April 2012 for an astrometric survey. Multiple overlaps per year are performed in a single bandpass (680$-$750 nm) using the "redlens" 20 cm aperture astrograph and a mosaic of large CCDs. Besides the regular, deep survey to magnitude 18.5, short exposures with an objective grating are taken to access stars as bright as 3rd magnitude. A brief overview of the program, observing and reductions is given. Positions on the 8 to 20 mas level are obtained of 66,202 Hipparcos stars at current epochs. These are compared to the Hipparcos Catalog to investigate its accuracy. About 20\\% of the observed Hipparcos stars are found to have inconsitent positions with the Hipparcos Catalog prediction on the 3 sigma level or over (about 75 mas or more discrepant position offsets). Some stars are now seen at an arcsec (or 25 sigma) off their Hipparcos Catalog predicted position.

  10. Asymmetric Surface Brightness Distribution of Altair Observed with the Navy Prototype Optical Interferometer

    E-Print Network [OSTI]

    Ohishi, N; Hutter, D J; Ohishi, Naoko; Nordgren, Tyler E.; Hutter, Donald J.

    2004-01-01

    An asymmetric surface brightness distribution of the rapidly rotating A7IV-V star, Altair, has been measured by the Navy Prototype Optical Interferometer (NPOI). The observations were recorded simultaneously using a triangle of three long baselines of 30m, 37m, and 64m, on 19 spectral channels, covering the wavelength range of 520nm to 850nm. The outstanding characteristics of these observations are (a) high resolution with the minimum fringe spacing of 1.7mas, easily resolving the 3-milliarcsecond (mas) stellar disk, and (b) the measurement of closure phase which is a sensitive indicator to the asymmetry of the brightness distribution of the source. Uniform disk diameters fit to the measured squared visibility amplitudes confirms the Altair's oblate shape due to its rapid rotation. The measured observables of Altair showed two features which are inconsistent with both the uniform-disk and limb-darkened disk models, while the measured observable of the comparison star, Vega, are consistent with the limb-darke...

  11. A radio-map of the colliding winds in the very massive binary system HD 93129A

    E-Print Network [OSTI]

    Benaglia, Paula; Moldon, Javier; Nelan, Ed; De Becker, Michael; Dougherty, Sean M; Koribalski, Baerbel

    2015-01-01

    Radio observations are an effective tool to discover particle acceleration regions in colliding-wind binaries, through detection of synchrotron radiation; these regions are natural laboratories for the study of relativistic particles. Wind-collision region (WCR) models can reproduce the radio continuum spectra of massive binaries that contain both thermal and non-thermal radio emission; however, key constraints for models come from high-resolution imaging. Only five WCRs have been resolved to date at radio frequencies at milliarcsec (mas) angular scales. The source HD 93129A, prototype of the very few known O2 I stars, is a promising target for study: recently, a second massive, early-type star about 50 mas away was discovered, and a non-thermal radio source detected in the region. Preliminary long-baseline array data suggest that a significant fraction of the radio emission from the system comes from a putative WCR. We sought evidence that HD 93129A is a massive binary system with colliding stellar winds tha...

  12. Interferometric Observation of the Highly Polarized SiO Maser Emission from the $v=1, J=5-4$ Transition Associated with VY Canis Majoris

    E-Print Network [OSTI]

    Hiroko Shinnaga; James M. Moran; Ken H. Young; Paul T. P. Ho

    2004-10-07

    We used the Submillimeter Array to image the SiO maser emission in the $v=1$, \\$J=5-4$ transition associated with the peculiar red supergiant VY Canis Majoris. We identified seven maser components and measured their relative positions and linear polarization properties. Five of the maser components are coincident to within about 150 mas ($\\sim$ 200 AU at the distance of 1.5 kpc); most of them may originate in the circumstellar envelope at a radius of about 50 mas from the star along with the SiO masers in the lowest rotational transitions. Our measurements show that two of the maser components may be offset from the inner stellar envelope (at the 3$\\sigma$ level of significance) and may be part of a larger bipolar outflow associated with VY CMa identified by Shinnaga et al. The strongest maser feature at a velocity of 35.9 kms$^{-1}$ has a 60 percent linear polarization, and its polarization direction is aligned with the bipolar axis. Such a high degree of polarization suggests that maser inversion is due to radiative pumping. Five of the other maser features have significant linear polarization.

  13. Structure of Sagittarius A* at 86 GHz using VLBI Closure Quantities

    E-Print Network [OSTI]

    S. S. Doeleman; Z. -Q. Shen; A. E. E. Rogers; G. C. Bower; M. C. H. Wright; J. -H. Zhao; D. C. Backer; J. W. Crowley; R. W. Freund; P. T. P. Ho; K. Y. Lo; D. P. Woody

    2001-02-13

    At radio wavelengths, images of the compact radio source Sagittarius A* (Sgr A*) in the Galactic Center are scatter broadened with a lambda^2 dependence due to an intervening ionized medium. We present VLBI observations of Sgr A* at 86 GHz using a six station array including the VLBA antennas at Pie Town, Fort Davis and Los Alamos, the 12m antenna at Kitt Peak and the millimeter arrays at Hat Creek and Owens Valley. To avoid systematic errors due to imperfect antenna calibration, the data were modeled using interferometric closure information. The data are best modeled by a circular Gaussian brightness distribution of FWHM 0.18 +- 0.02 mas. The data are also shown to be consistent with an elliptical model corresponding to the scattering of a point source. The source structure in the N-S direction, which is less well determined than in the E-W direction due to the limited N-S (u,v) coverage of the array, is constrained to be less than 0.27 mas by these measurements. These results are consistent with extrapolations of intrinsic structure estimates obtained with VLBI at 7mm wavelength assuming the intrinsic size of Sgr A* has a greater dependence than lambda^0.9 with wavelength.

  14. The off-axis jet structure in Mrk 501 at mm-wavelengths

    E-Print Network [OSTI]

    Shoko Koyama; Motoki Kino; Marcello Giroletti; Akihiro Doi; Hiroshi Nagai; Kazuhiro Hada; Kotaro Niinuma; Monica Orienti; Gabriele Giovannini; Eduardo Ros; Tuomas Savolainen; Miguel A. Pérez-Torres; Thomas P. Krichbaum

    2015-05-17

    We present results from 43 GHz (VLBA, six epochs from 2012.2 to 2013.2) and 86 GHz (GMVA, one epoch in 2012.4) observations toward the basis of the jet in the TeV Blazar Mrk 501. The 43-GHz data analysis reveals a new feature located northeast of the radio core, with a flux density of several tens of mJy, perpendicularly to the jet axis. The 86-GHz image shows the jet feature located 0.75 mas southeast of the radio core, which is consistent with the previous result. The location of Gaussian model for 0.75 mas feature does not coincide with those for the jets in the 43-GHz image, however, a distribution of emission is found. We also discuss the spectral indices of the core, the northeast feature, and the jet feature between 43 GHz and 86 GHz, which show flat-to-steep, steep, and flat-to-invert, respectively.

  15. A new combined nuclear magnetic resonance and Raman spectroscopic probe applied to in situ investigations of catalysts and catalytic processes

    SciTech Connect (OSTI)

    Camp, Jules C. J.; Mantle, Michael D.; York, Andrew P. E.; McGregor, James

    2014-06-15

    Both Raman and nuclear magnetic resonance (NMR) spectroscopies are valuable analytical techniques capable of providing mechanistic information and thereby providing insights into chemical processes, including catalytic reactions. Since both techniques are chemically sensitive, they yield not only structural information but also quantitative analysis. In this work, for the first time, the combination of the two techniques in a single experimental apparatus is reported. This entailed the design of a new experimental probe capable of recording simultaneous measurements on the same sample and/or system of interest. The individual datasets acquired by each spectroscopic method are compared to their unmodified, stand-alone equivalents on a single sample as a means to benchmark this novel piece of equipment. The application towards monitoring reaction progress is demonstrated through the evolution of the homogeneous catalysed metathesis of 1?hexene, with both experimental techniques able to detect reactant consumption and product evolution. This is extended by inclusion of magic angle spinning (MAS) NMR capabilities with a custom made MAS 7 mm rotor capable of spinning speeds up to 1600 Hz, quantified by analysis of the spinning sidebands of a sample of KBr. The value of this is demonstrated through an application involving heterogeneous catalysis, namely the metathesis of 2-pentene and ethene. This provides the added benefit of being able to monitor both the reaction progress (by NMR spectroscopy) and also the structure of the catalyst (by Raman spectroscopy) on the very same sample, facilitating the development of structure-performance relationships.

  16. Compact Radio Sources within 30" of Sgr A*: Proper Motions, Stellar Winds and the Accretion Rate onto Sgr A*

    E-Print Network [OSTI]

    Yusef-Zadeh, F; Schödel, R; Wardle, M; Cotton, W; Roberts, D A; Nogueras-Lara, F; Gallego-Cano, E

    2015-01-01

    Recent broad-band 34 and 44 GHz radio continuum observations of the Galactic center have revealed 41 massive stars identified with near-IR counterparts, as well as 44 proplyd candidates within 30" of Sgr A*. Radio observations obtained in 2011 and 2014 have been used to derive proper motions of eight young stars near Sgr A*. The accuracy of proper motion estimates based on near-IR observations by Lu et al. and Paumard et al. have been investigated by using their proper motions to predict the 2014 epoch positions of near-IR stars and comparing the predicted positions with those of radio counterparts in the 2014 radio observations. Predicted positions from Lu et al. show an rms scatter of 6 mas relative to the radio positions, while those from Paumard et al. show rms residuals of 20 mas, which is mainly due to uncertainties in the IR-based proper motions. Under the assumption of homogeneous ionized winds, we also determine the mass-loss rates of 11 radio stars, finding rates that are on average $\\sim$2 times sm...

  17. Formation and evolution of the water maser outflow event in AFGL 2591 VLA 3-N

    E-Print Network [OSTI]

    Trinidad, M A; Estalella, R; Cantó, J; Raga, A; Torrelles, J M; Patel, N A; Gómez, J F; Anglada, G; Carrasco-González, C; Rodríguez, L F

    2012-01-01

    In this paper we analyze multi-epoch Very Long Baseline Interferometry (VLBI) water maser observations carried out with the Very Long Baseline Array (VLBA) toward the high-mass star-forming region AFGL 2591. We detected maser emission associated with the radio continuum sources VLA 2 and VLA 3. In addition, a water maser cluster, VLA 3-N, was detected ~ 0.5" north of VLA 3. We concentrate the discussion of this paper on the spatio-kinematical distribution of the water masers towards VLA 3-N. The water maser emission toward the region VLA 3-N shows two bow shock-like structures, Northern and Southern, separated from each other by ~ 100 mas (~ 330 AU). The spatial distribution and kinematics of the water masers in this cluster have persisted over a time span of seven years. The Northern bow shock has a somewhat irregular morphology, while the Southern one has a remarkably smooth morphology. We measured the proper motions of 33 water maser features, which have an average proper motion velocity of ~ 1.3 mas/yr (~...

  18. Annual Parallax Distance and Secular Motion of the Water Fountain Source IRAS 18286-0959

    E-Print Network [OSTI]

    Imai, Hiroshi; Honma, Mareki; Miyaji, Takeshi

    2012-01-01

    We report on results of astrometric observations of water vapor masers in the "water fountain" source IRAS 18286-0959 (I18286) with the VLBI Exploration of Radio Astrometry (VERA). These observations yielded an annual parallax of IRAS 18286-0959, pi=0.277+/-0.041 mas, corresponding to a heliocentric distance of D=3.61(+0.63)(-0.47) kpc. The maser feature, whose annual parallax was measured, showed the absolute proper motion of (mu_alpha, mu_delta)=(-3.2 +/- 0.3, -7.2 +/- 0.2) [mas/yr]. The intrinsic motion of the maser feature in the internal motions of the cluster of features in I18286 does not seem to trace the motion of the bipolar jet of I18286. Taking into account this intrinsic motion, the derived motion of the maser feature is roughly equal to that of the maser source I18286 itself. The proximity of I18286 to the Galactic midplane (z~10 pc) suggests that the parental star of the water fountain source in I18286 should be intermediate-mass AGB/post-AGB star, but the origin of a large deviation of the sys...

  19. Investigations of low amplitude radio frequency pulses at and awayfro m rotary resonance conditions for I = 5/2 nuclei

    SciTech Connect (OSTI)

    Logan, John W.; Urban, Jeffry T.; Walls, Jamie D.; Lim, KwangHun; Jerschow, Alexej; Pines, Alexander

    2002-04-15

    Additional experimental evidence of rotary resonance effects for multiple-quantum coherence conversion in a spin-5/2 system is presented. Two dimensional plots of the relative efficiency of MQ excitation and conversion are given as a function of radio frequency (rf) amplitude and pulse width. Data are presented for the excitation of five-quantum coherence (5QC), as well as for 5QC to three-quantum coherence (3QC) conversion, 5QC to 1QC (the central transition coherence) conversion, and 3QC to 1QC conversion. A two-fold increase in the signal-to-noise ratio is achieved by substituting low amplitude rf pulses in place of hard rf pulses for 5QC excitation and 5QC to 3QC conversion in a mixed multiple-quantum MAS (MMQMAS) experiment. The anisotropic line shape for the low amplitude rf pulse version of the MMQMAS experiment was observed to be distorted from the MAS line shape. The cause and implications of the distortion are discussed.

  20. Observations of the pulsation of the Cepheid l Car with the Sydney University Stellar Interferometer

    E-Print Network [OSTI]

    J. Davis; A. P. Jacob; J. G. Robertson; M. J. Ireland; J. R. North; W. J. Tango; P. G. Tuthill

    2008-12-28

    Observations of the southern Cepheid l Car to yield the mean angular diameter and angular pulsation amplitude have been made with the Sydney University Stellar Interferometer (SUSI) at a wavelength of 696 nm. The resulting mean limb-darkened angular diameter is 2.990+-0.017 mas (i.e. +-0.6 per cent) with a maximum-to-minimum amplitude of 0.560+-0.018 mas corresponding to 18.7+-0.6 per cent in the mean stellar diameter. Careful attention has been paid to uncertainties, including those in measurements, in the adopted calibrator angular diameters, in the projected values of visibility squared at zero baseline, and to systematic effects. No evidence was found for a circumstellar envelope at 696 nm. The interferometric results have been combined with radial displacements of the stellar atmosphere derived from selected radial velocity data taken from the literature to determine the distance and mean diameter of l Car. The distance is determined to be 525+-26 pc and the mean radius 169+-8R{solar). Comparison with published values for the distance and mean radius show excellent agreement, particularly when a common scaling factor from observed radial velocity to pulsation velocity of the stellar atmosphere (the p-factor) is used.

  1. A `Water Spout' Maser Jet in S235AB-MIR

    E-Print Network [OSTI]

    Burns, Ross A; Handa, Toshihiro; Omodaka, Toshihiro; Nakagawa, Akiharu; Nagayama, Takumi; Ueno, Yuji

    2015-01-01

    We report on annual parallax and proper motion observations of H2O masers in S235AB-MIR, which is a massive young stellar object in the Perseus Arm. Using multi-epoch VLBI astrometry we measured a parallax of pi = 0.63 +- 0.03 mas, corresponding to a trigonometric distance of D = 1.56+-0.09 kpc, and source proper motion of ( u alpha cos d , u d) = (0.79 +- 0.12, -2.41 +- 0.14) mas/yr. Water masers trace a jet of diameter 15 au which exhibits a definite radial velocity gradient perpendicular to its axis. 3D maser kinematics were well modelled by a rotating cylinder with physical parameters: v_out = 45+-2 km/s, v_rot = 22+-3 km/s, i = 12+-2 degrees, which are the outflow velocity, tangential rotation velocity and line-of-sight inclination, respectively. One maser feature exhibited steady acceleration which may be related to the jet rotation. During our 15 month VLBI programme there were three `maser burst' events caught `in the act' which were caused by the overlapping of masers along the line of sight.

  2. Proper Motion Study of the Magellanic Clouds using SPM material

    E-Print Network [OSTI]

    Katherine, Vieira; William, van Altena; Norbert, Zacharias; Dana, Casetti-Dinescu; Vladimir, Korchagin; Imants, Platais; David, Monet; Carlos, Lopez

    2010-01-01

    Absolute proper motions are determined for stars and galaxies to V=17.5 over a 450 square-degree area that encloses both Magellanic Clouds. The proper motions are based on photographic and CCD observations of the Yale/San Juan Southern Proper Motion program, which span over a baseline of 40 years. Multiple, local relative proper motion measures are combined in an overlap solution using photometrically selected Galactic Disk stars to define a global relative system that is then transformed to absolute using external galaxies and Hipparcos stars to tie into the ICRS. The resulting catalog of 1.4 million objects is used to derive the mean absolute proper motions of the Large Magellanic Cloud and the Small Magellanic Cloud; $(\\mu_\\alpha\\cos\\delta,\\mu_\\delta)_{LMC}=(1.89,+0.39)\\pm (0.27,0.27)\\;\\;\\{mas yr}^{-1}$ and $(\\mu_\\alpha\\cos\\delta,\\mu_\\delta)_{SMC}=(0.98,-1.01)\\pm (0.30,0.29)\\;\\;\\{mas yr}^{-1}$. These mean motions are based on best-measured samples of 3822 LMC stars and 964 SMC stars. A dominant portion (0....

  3. Clay Minerals

    SciTech Connect (OSTI)

    Mueller, Karl T.; Sanders, Rebecca L.; Washton, Nancy M.

    2014-03-14

    Clay minerals are important components of the environment and are involved or implicated in processes such as the uptake of pollutants and the release of nutrients and as potential platforms for a number of chemical reactions. Owing to their small particle sizes (typically, on the order of microns or smaller) and mixing with a variety of other minerals and soil components, advanced characterization methods are needed to study their structures, dynamics, and reactivities. In this article, we describe the use of solid-state NMR methods to characterize the structures and chemistries of clay minerals. Early one-pulse magic-angle spinning (MAS) NMR studies of 27Al and 29Si have now been enhanced and extended with new studies utilizing advanced methodologies (such as Multiple Quantum MAS) as well as studies of less-sensitive nuclei. In additional work, the issue of reactivity of clay minerals has been addressed, including studies of reactive surface area in the environment. Utilizations of NMR-sensitive nuclides within the clay minerals themselves, and in molecules that react with speci?c sites on the clay mineral surfaces, have aided in understanding the reactivity of these complex aluminosilicate systems.

  4. ON THE CONNECTION OF THE APPARENT PROPER MOTION AND THE VLBI STRUCTURE OF COMPACT RADIO SOURCES

    SciTech Connect (OSTI)

    Moor, A.; Frey, S. [FOeMI Satellite Geodetic Observatory, P.O. Box 585, H-1592 Budapest (Hungary); Lambert, S. B. [Observatoire de Paris, Departement Systemes de Reference Temps Espace (SYRTE), CNRS/UMR8630, 75014 Paris (France); Titov, O. A. [Geoscience Australia, P.O. Box 378, Canberra 2601 (Australia); Bakos, J., E-mail: moor@konkoly.hu, E-mail: frey@sgo.fomi.hu, E-mail: sebastien.lambert@obspm.fr, E-mail: oleg.titov@ga.gov.au, E-mail: jbakos@iac.es [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain)

    2011-06-15

    Many of the compact extragalactic radio sources that are used as fiducial points to define the celestial reference frame are known to have proper motions detectable with long-term geodetic/astrometric very long baseline interferometry (VLBI) measurements. These changes can be as high as several hundred microarcseconds per year for certain objects. When imaged with VLBI at milliarcsecond (mas) angular resolution, these sources (radio-loud active galactic nuclei) typically show structures dominated by a compact, often unresolved 'core' and a one-sided 'jet'. The positional instability of compact radio sources is believed to be connected with changes in their brightness distribution structure. For the first time, we test this assumption in a statistical sense on a large sample rather than on only individual objects. We investigate a sample of 62 radio sources for which reliable long-term time series of astrometric positions as well as detailed 8 GHz VLBI brightness distribution models are available. We compare the characteristic direction of their extended jet structure and the direction of their apparent proper motion. We present our data and analysis method, and conclude that there is indeed a correlation between the two characteristic directions. However, there are cases where the {approx}1-10 mas scale VLBI jet directions are significantly misaligned with respect to the apparent proper motion direction.

  5. DISCOVERY OF SUB- TO SUPERLUMINAL MOTIONS IN THE M87 JET: AN IMPLICATION OF ACCELERATION FROM SUB-RELATIVISTIC TO RELATIVISTIC SPEEDS

    SciTech Connect (OSTI)

    Asada, Keiichi; Nakamura, Masanori; Inoue, Makoto; Doi, Akihiro; Nagai, Hiroshi E-mail: nakamura@asiaa.sinica.edu.tw

    2014-01-20

    The velocity field of the M87 jet from milli-arcsecond (mas) to arcsecond scales is extensively investigated together with new radio images taken from European VLBI Network (EVN) observations. We detected proper motions of components located at between 160 mas from the core and the HST-1 complex for the first time. Newly derived velocity fields exhibit a systematic increase from sub- to superluminal speeds in the upstream of HST-1. If we assume that the observed velocities reflect the bulk flow, here we suggest that the M87 jet may be gradually accelerated through a distance of 10{sup 6} times the Schwarzschild radius of the supermassive black hole. The acceleration zone is co-spatial with the jet parabolic region, which is interpreted as the collimation zone of the jet. The acceleration and collimation take place simultaneously, which we suggest is characteristic of magnetohydrodynamic flows. The distribution of the velocity field has a peak at HST-1, which is considered as the site of over-collimation, and shows a deceleration downstream of HST-1 where the jet is conical. Our interpretation of the velocity map in the M87 jet provides a hypothesis for active galactic nuclei which suggests that the acceleration and collimation zone of relativistic jets extends over the whole scale within the sphere of influence of the supermassive black hole.

  6. Connection between inner jet kinematics and broadband flux variability in the BL Lac object S5 0716+714

    E-Print Network [OSTI]

    Rani, B; Marscher, A P; Hodgson, J A; Fuhrmann, L; Angelakis, E; Britzen, S; Zensus, J A

    2015-01-01

    We present a high-frequency very long baseline interferometry (VLBI) kinematical study of the BL Lac object S5 0716+714 over the time period of September 2008 to October 2010. The aim of the study is to investigate the relation of the jet kinematics to the observed broadband flux variability. We find significant non-radial motions in the jet outflow of the source. In the radial direction, the highest measured apparent speed is \\sim37 c, which is exceptionally high, especially for a BL Lac object. Patterns in the jet flow reveal a roughly stationary feature \\sim0.15 mas downstream of the core. The long-term fits to the component trajectories reveal acceleration in the sub-mas region of the jet. The measured brightness temperature, T_{B}, follows a continuous trend of decline with distance, T_B \\propto r_{jet}^{-(2.36\\pm0.41)}, which suggests a gradient in Doppler factor along the jet axis. Our analysis suggest that a moving disturbance (or a shock wave) from the base of the jet produces the high-energy (optica...

  7. The effect of O{sub 2} intercalation on the rotational dynamics and the ordering transition of C{sub 60}

    SciTech Connect (OSTI)

    Myers, S.A.; Assink, R.A.; Schirber, J.E.; Loy, D.A.

    1995-01-01

    We have used {sup 13}C magic-angle spinning (MAS) nuclear magnetic resonance (NMR) to characterize the structure and rotational dynamics of C{sub 60} containing oxygen molecules located in the interstitial sites of the fcc lattice. Under normal conditions, a narrow peak at 143.7 ppm is observed for C{sub 60}. When exposed to oxygen at moderate pressures, several additional resonances appear in the {sup 13}C MAS NMR spectrum. These secondary resonances are shifted downfield from the main peak at 143.7 ppm and are due to the Fermi-contact interaction of the paramagnetic oxygen molecules with the {sup 13}C nuclear spins. The presence of oxygen depresses the orientational ordering transition by ca. 20 K as observed by DSC. The spin-lattice relaxation time (T{sub 1}) of each secondary peak shows a minimum near the ordering transition, indicating that this transition is not dependent on the number of oxygen molecules surrounding an individual C{sub 60} molecule. The T{sub 1}, due to paramagnetic relaxation, normalized by the number of surrounding oxygen molecules, is constant. This observation demonstrates that within a given sample, the dynamics of C{sub 60} molecules are independent of the number of surrounding oxygen molecules.

  8. Validation of Minor Actinide Cross Sections by Studying Samples Irradiated for 492 Days at the Dounreay Prototype Fast Reactor - II: Burnup Calculations

    SciTech Connect (OSTI)

    Tsujimoto, K. [Japan Atomic Energy Research Institute (Japan); Kohno, N. [Japan Atomic Energy Research Institute (Japan); Shinohara, N. [Japan Atomic Energy Research Institute (Japan); Sakurai, T. [Japan Atomic Energy Research Institute (Japan); Nakahara, Y. [Japan Atomic Energy Research Institute (Japan); Mukaiyama, T. [Japan Atomic Energy Research Institute (Japan); Raman, S. [Oak Ridge National Laboratory (United States)

    2003-06-15

    To evaluate neutron cross-section data of minor actinides (MAs), separated actinide samples and dosimetry samples were irradiated at the Dounreay Prototype Fast Reactor for 492 effective full-power days. Irradiated samples were analyzed both at Oak Ridge National Laboratory and at Japan Atomic Energy Research Institute (JAERI). This independent duplication has resulted in the generation of reliable radiochemical analysis data. Based on the burnup calculations of major actinide ({sup 235}U and {sup 239}Pu) and dosimetry samples, the neutron flux distribution and the flux level were adjusted at the locations where MA samples were irradiated. The burnup calculations were carried out for MAs using the determined flux distribution and flux level. The calculated results were compared with the experimental data. A brief description of sample preparation and irradiation and a detailed discussion of radiochemical analysis at JAERI are given in a companion paper. The current paper discusses the burnup calculations and the validation of MA cross-section data in evaluated nuclear data libraries.

  9. Limits on Enhanced Radio Wave Scattering by Supernova Remnants

    E-Print Network [OSTI]

    Laura G. Spitler; Steven R. Spangler

    2005-06-28

    We report multifrequency observations with the NRAO Very Long Baseline Array (VLBA) of the compact radio sources J0128+6306 and J0547+2721, which are viewed through the supernova remnants G127.1+0.5 and S147, respectively. Observations were made at frequencies of 1.427, 1.667, 2.271, and 4.987 GHz. The lines of sight to these sources pass through the shock wave and upstream and downstream turbulent layers of their respective supernova remnants, and thus might detect cosmic-ray generated turbulence produced during the Fermi acceleration process. For both sources, we detect interstellar scattering, characterized by a component of the angular size which scales as the square of the observing wavelength. The magnitude of the scattering is characterized by an effective scattering angular size theta_S0 at a frequency of 1 GHz of 13.2 +/- 2.6 milliarcseconds (mas) for J0128+6306 and 6.7 +/- 2.2 mas for J0547+2721. These angular sizes are consistent with the ``incidental'' scattering for any line of sight out of the galaxy at similar galactic latitudes and longitudes. There is therefore no evidence for enhanced turbulence at these supernova remnants. We establish upper limits to the supernova remnant-associated scattering measures of 8.1-14.8 m^-20/3-pc for J0128+6306 and 3.0 m^-20/3-pc for J0547+2721.

  10. THE FOURTH US NAVAL OBSERVATORY CCD ASTROGRAPH CATALOG (UCAC4)

    SciTech Connect (OSTI)

    Zacharias, N.; Finch, C. T.; Bartlett, J. L.; Girard, T. M.; Henden, A.; Monet, D. G.; Zacharias, M. I.

    2013-02-01

    The fourth United States Naval Observatory (USNO) CCD Astrograph Catalog, UCAC4, was released in 2012 August (double-sided DVD and CDS data center Vizier catalog I/322). It is the final release in this series and contains over 113 million objects; over 105 million of them with proper motions (PMs). UCAC4 is an updated version of UCAC3 with about the same number of stars also covering all-sky. Bugs were fixed, Schmidt plate survey data were avoided, and precise five-band photometry was added for about half the stars. Astrograph observations have been supplemented for bright stars by FK6, Hipparcos, and Tycho-2 data to compile a UCAC4 star catalog complete from the brightest stars to about magnitude R = 16. Epoch 1998-2004 positions are obtained from observations with the 20 cm aperture USNO Astrograph's 'red lens', equipped with a 4k by 4k CCD. Mean positions and PMs are derived by combining these observations with over 140 ground- and space-based catalogs, including Hipparcos/Tycho and the AC2000.2, as well as unpublished measures of over 5000 plates from other astrographs. For most of the faint stars in the southern hemisphere, the first epoch plates from the Southern Proper Motion program form the basis for PMs, while the Northern Proper Motion first epoch plates serve the same purpose for the rest of the sky. These data are supplemented by 2MASS near-IR photometry for about 110 million stars and five-band (B, V, g, r, i) APASS data for over 51 million stars. Thus the published UCAC4, as were UCAC3 and UCAC2, is a compiled catalog with the UCAC observational program being a major component. The positional accuracy of stars in UCAC4 at mean epoch is about 15-100 mas per coordinate, depending on magnitude, while the formal errors in PMs range from about 1 to 10 mas yr{sup -1} depending on magnitude and observing history. Systematic errors in PMs are estimated to be about 1-4 mas yr{sup -1}.

  11. Regmi Research Series ,Year 2, January 1, 1970

    E-Print Network [OSTI]

    Regmi, Mahesh C

    1970-01-01

    , Vol. lIT, Part I, P. 214. lD.rhere exists considerable ~1f.terc~c9 ,in the ma~s of t he Sanskrit term Kirat and the term as it is used in' our 1anguage~ In ' the 15th century, the Sen Kings of Hakwanpur described areas occupied by Magars as "Magarat... ." In the 16th century, the San Kings conquered the hill ragUrns aast of t.h l3 Dudhkoshi river as well as tha Tarai rtlglons of Saptari and Morang. The h:ill .r"6r;t0ns east of the Dudhkosh1. .'Woro inhabited by Kirats, who were contcrnp- , tuousl.Y called...

  12. The deflection of light induced by the Sun's gravitational field and measured with geodetic VLBI

    E-Print Network [OSTI]

    O. Titov; A. Girdiuk

    2015-11-02

    The Sun's gravitational field deflects the apparent positions of close objects in accordance with the formulae of general relativity. Optical astrometry is used to test the prediction, but only with the stars close to the Sun and only during total Solar eclipses. Geodetic Very Long Baseline Interferometry (VLBI) is capable of measuring the deflection of the light from distant radio sources anytime and across the whole sky. We show that the effect of light deflection is equivalent to the gravitational delay calculated during the reduction of VLBI data. All reference radio sources display an annual circular motion with the magnitude proportional to their ecliptic latitude. In particular, radio sources near the ecliptic pole draw an annual circle with magnitude of 4 mas. This effect could be easily measured with the current precision of the geodetic VLBI data.

  13. Initial Aging Studies of Unfilled VCE

    SciTech Connect (OSTI)

    Letant, S E; Herberg, J L; Wilson, T S; Alviso, C T; Chinn, S C; Maxwell, R S

    2008-10-09

    This report presents initial data on the effects of temperature, oxygen, and radiation on the chemical and structural properties of newly formulated, unfilled VCE. This initial effort focused on a pristine sample, and a replicate sample irradiated in air at a dose of 25MR. Thermal degradation was investigated by performing Thermogravimetric Analysis (TGA), and radiation-induced degradation was investigated using Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Solid Phase MicroExtraction--Gas Chromatography/Mass Spectrometry (SPME-GC/MS), as well as various Nuclear Magnetic Resonance (NMR) techniques including: {sup 13}C, {sup 13}C {sup 1}H cross polarization (CP), and {sup 1}H magic angle spinning (MAS) NMR.

  14. Aging Studies of Filled and Unfilled VCE

    SciTech Connect (OSTI)

    Letant, S; Herberg, J; Alviso, C; Small, W; Mulcahy, H; Pearson, M; Wilson, T; Chinn, S; Maxwell, R

    2009-11-10

    This report presents data on the effects of temperature and gamma radiation on the chemical and structural properties of both filled and unfilled VCE material produced by the Kansas City Plant using WR-qualified processes. Thermal effects up to 300 C and gamma irradiation doses of 1 MRad and 25 MRad were investigated under atmospheric conditions. Characterization techniques used in the study comprise Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Tensile Testing, Solid Phase MicroExtraction - Gas Chromatography/Mass Spectrometry (SPME-GC/MS), phenol extraction followed by HPLC, and various Nuclear Magnetic Resonance (NMR) techniques including: {sup 13}C, {sup 13}C {l_brace}{sup 1}H{r_brace} cross polarization (CP), {sup 1}H magic angle spinning (MAS), 13C{l_brace}{sup 1}H{r_brace} Wide-line-Separation (2D-WISE) and development of Center band-Only Detection of Exchange (CODEX).

  15. Influence of hydroxyl contents on photocatalytic activities of polymorphic titania nanoparticles

    SciTech Connect (OSTI)

    kaewguna, Sujaree; Nolpha, Christopher A.; Lee, Burtrand I.; Wang, Li Q.

    2009-03-15

    Polymorphic titania nanoparticles, prepared by a Water-based Ambient Condition Sol (WACS) process, were post-treated by a Solvent-based Ambient Condition Sol (SACS) process in sec-butanol. All samples were characterized for phase composition, surface area, lattice hydroxyl contamination, and particle morphology by X-ray diffraction, N2 physisorption, FT-IR, solid state Magic Angle Spinning (MAS) 1H NMR and scanning electron microscopy. The resultswerecompared to acommercial titania, Degussa P25. Evaluation of methyl orange degradation under UV irradiation results showed that the lower lattice hydroxyl content in SACS titania nanoparticles enhances photocatalytic activity. As-prepared titania and post-treated SACS samples, which have similar surface areas and crystallinity, were compared in order to prove that the superior photocatalytic activity came from a reduction in lattice hydroxyl content.

  16. High-resolution NMR spectroscopy of biological tissues usingprojected Magic Angle Spinning

    SciTech Connect (OSTI)

    Martin, Rachel W.; Jachmann, Rebecca C.; Sakellariou, Dimitris; Nielsen, Ulla Gro; Pines, Alexander

    2005-01-27

    High-resolution NMR spectra of materials subject toanisotropic broadening are usually obtained by rotating the sample aboutthe magic angle, which is 54.7 degrees to the static magnetic field. Inprojected Magic Angle Spinning (p-MAS), the sample is spun about twoangles, neither of which is the magic angle. This provides a method ofobtaining isotropic spectra while spinning at shallow angles. The p-MASexperiment may be used in situations where spinning the sample at themagic angle is not possible due to geometric or other constraints,allowing the choice of spinning angle to be determined by factors such asthe shape of the sample, rather than by the spin physics. The applicationof this technique to bovine tissue samples is demonstrated as a proof ofprinciple for future biological or medical applications.

  17. FEASIBILITY OF RECYCLING PLUTONIUM AND MINOR ACTINIDES IN LIGHT WATER REACTORS USING HYDRIDE FUEL

    SciTech Connect (OSTI)

    Greenspan, Ehud; Todreas, Neil; Taiwo, Temitope

    2009-03-10

    The objective of this DOE NERI program sponsored project was to assess the feasibility of improving the plutonium (Pu) and minor actinide (MA) recycling capabilities of pressurized water reactors (PWRs) by using hydride instead of oxide fuels. There are four general parts to this assessment: 1) Identifying promising hydride fuel assembly designs for recycling Pu and MAs in PWRs 2) Performing a comprehensive systems analysis that compares the fuel cycle characteristics of Pu and MA recycling in PWRs using the promising hydride fuel assembly designs identified in Part 1 versus using oxide fuel assembly designs 3) Conducting a safety analysis to assess the likelihood of licensing hydride fuel assembly designs 4) Assessing the compatibility of hydride fuel with cladding materials and water under typical PWR operating conditions Hydride fuel was found to offer promising transmutation characteristics and is recommended for further examination as a possible preferred option for recycling plutonium in PWRs.

  18. First Parallax Measurements Towards a 6.7 GHz Methanol Maser with the Australian Long Baseline Array - Distance to G339.884-1.259

    E-Print Network [OSTI]

    Krishnan, V; Reid, M J; Brunthaler, A; Sanna, A; McCallum, J; Reynolds, C; Bignall, H E; Phillips, C J; Dodson, R; Rioja, M; Caswell, J L; Chen, X; Dawson, J R; Fujisawa, K; Goedhart, S; Green, J A; Hachisuka, K; Honma, M; Menten, K; Shen, Z Q; Voronkov, M A; Walsh, A J; Xu, Y; Zhang, B; Zheng, X W

    2015-01-01

    We have conducted the first parallax and proper motion measurements of 6.7 GHz methanol maser emission using the Australian Long Baseline Array (LBA). The parallax of G339.884$-$1.259 measured from five epochs of observations is 0.48$\\pm $0.08 mas, corresponding to a distance of $2.1^{+0.4}_{-0.3}$ kpc, placing it in the Scutum spiral arm. This is consistent (within the combined uncertainty) with the kinematic distance estimate for this source at 2.5$\\pm $0.5 kpc using the latest Solar and Galactic rotation parameters. We find from the Lyman continuum photon flux that the embedded core of the young star is of spectral type B1, demonstrating that luminous 6.7 GHz methanol masers can be associated with high-mass stars towards the lower end of the mass range.

  19. An Eulerian PPM & PIC Code for Cosmological Hydrodynamics

    E-Print Network [OSTI]

    A. Sornborger; B. Fryxell; K. Olson; P. MacNeice

    1996-08-05

    We present a method for integrating the cosmological hydrodynamical equations including a collisionless dark matter component. For modelling the baryonic matter component, we use the Piecewise Parabolic Method (PPM) which is a high-accuracy shock capturing technique. The dark matter component is modeled using gravitationally interacting particles whose evolution is determined using standard particle-in-cell techniques. We discuss details of the inclusion of gravity and expansion in the PPM code and give results of a number of tests of the code. This code has been developed for a massively parallel, SIMD supercomputer: the MasPar MP-2 parallel processor. We present details of the techniques we have used to implement the code for this architecture and discuss performance of the code on the MP-2. The code processes $5.0 \\times 10^4$ grid zones per second and requires 53 seconds of machine time for a single timestep in a $128^3$ simulation.

  20. Prospects of cold dark matter searches with an ultra-low-energy germanium detector

    E-Print Network [OSTI]

    H. T. Wong

    2007-11-08

    The report describes the research program on the development of ultra-low-energy germanium detectors, with emphasis on WIMP dark matter searches. A threshold of 100 eV is achieved with a 20 g detector array, providing a unique probe to the low-mas WIMP. Present data at a surface laboratory is expected to give rise to comparable sensitivities with the existing limits at the $\\rm{5 - 10 GeV}$ WIMP-mass range. The projected parameter space to be probed with a full-scale, kilogram mass-range experiment is presented. Such a detector would also allow the studies of neutrino-nucleus coherent scattering and neutrino magnetic moments.

  1. The Use of Conversation in the English Novel

    E-Print Network [OSTI]

    Schafer, Bertha B.

    1896-01-01

    Libraries’ Center for Digital Scholarship. http://kuscholarworks.ku.edu Submitted to the Department of English of the University of Kansas in partial fulfillment of the requirements for the Degree of Master of Arts Mas te r T h e s i s E n g l i s h S c... h a f e r , F e r t h a 1896 Use o f c o n v e r s a t i o n i n the E n g l i s h n o v e l * THE USE OF CONVERSATION IN THE ENGLISH NOVELL C h a p t e r I ft - x f r J J O , t h e p o o r I n d i a n o f the newspaper j o k e s , w h o i...

  2. Conceptual design of minor actinides burner with an accelerator-driven subcritical system.

    SciTech Connect (OSTI)

    Cao, Y.; Gohar, Y. (Nuclear Engineering Division)

    2011-11-04

    In the environmental impact study of the Yucca Mountain nuclear waste repository, the limit of spent nuclear fuel (SNF) for disposal is assessed at 70,000 metric tons of heavy metal (MTHM), among which 63,000 MTHM are the projected SNF discharge from U.S. commercial nuclear power plants though 2011. Within the 70,000 MTHM of SNF in storage, approximately 115 tons would be minor actinides (MAs) and 585 tons would be plutonium. This study describes the conceptual design of an accelerator-driven subcritical (ADS) system intended to utilize (burn) the 115 tons of MAs. The ADS system consists of a subcritical fission blanket where the MAs fuel will be burned, a spallation neutron source to drive the fission blanket, and a radiation shield to reduce the radiation dose to an acceptable level. The spallation neutrons are generated from the interaction of a 1 GeV proton beam with a lead-bismuth eutectic (LBE) or liquid lead target. In this concept, the fission blanket consists of a liquid mobile fuel and the fuel carrier can be LBE, liquid lead, or molten salt. The actinide fuel materials are dissolved, mixed, or suspended in the liquid fuel carrier. Therefore, fresh fuel can be fed into the fission blanket to adjust its reactivity and to control system power during operation. Monte Carlo analyses were performed to determine the overall parameters of an ADS system utilizing LBE as an example. Steady-state Monte Carlo simulations were studied for three fission blanket configurations that are similar except that the loaded amount of actinide fuel in the LBE is either 5, 7, or 10% of the total volume of the blanket, respectively. The neutron multiplication factor values of the three configurations are all approximately 0.98 and the MA initial inventories are each approximately 10 tons. Monte Carlo burnup simulations using the MCB5 code were performed to analyze the performance of the three conceptual ADS systems. Preliminary burnup analysis shows that all three conceptual ADS systems consume about 1.2 tons of actinides per year and produce 3 GW thermal power, with a proton beam power of 25 MW. Total MA fuel that would be consumed in the first 10 years of operation is 9.85, 11.80, or 12.68 tons, respectively, for the systems with 5, 7, or 10% actinide fuel particles loaded in the LBE. The corresponding annual MA fuel transmutation rate after reaching equilibrium at 10 years of operation is 0.83, 0.94, or 1.02 tons/year, respectively. Assuming that the ADS systems can be operated for 35 full-power years, the total MAs consumed in the three ADS systems are 30.6, 35.3, and 37.2 tons, respectively. For the three configurations, it is estimated that 3.8, 3.3, or 3.1 ADS system units are required to utilize the entire 115 tons of MA fuel in the SNF inventory, respectively.

  3. Scientific Results from High-precision Astrometry at the Palomar Testbed Interferometer

    E-Print Network [OSTI]

    Matthew W. Muterspaugh; Benjamin F. Lane; Maciej Konacki; B. F. Burke; M. M. Colavita; S. R. Kulkarni; M. Shao

    2006-05-31

    A new observing mode for the Palomar Testbed Interferometer was developed in2002-2003 which enables differential astrometry at the level of 20 micro-arcseconds for binary systems with separations of several hundred milli-arcseconds (mas). This phase-referenced mode is the basis of the Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES), a search for giant planets orbiting either the primary or secondary star in fifty binary systems. We present the first science results from the PHASES search. The properties of the stars comprising binary systems are determined to high precision. The mutual inclinations of several hierarchical triple star systems have been determined. We will present upper limits constraining the the existence of giant planets in a few of the target systems.

  4. Trigonometric Parallaxes of Central Stars of Planetary Nebulae

    E-Print Network [OSTI]

    Hugh C. Harris; Conard C. Dahn; Blaise Canzian; Harry H. Guetter; S. K. Leggett; Stephen E. Levine; Christian B. Luginbuhl; Alice K. B. Monet; David G. Monet; Jeffrey R. Pier; Ronald C. Stone; Trudy Tilleman; Frederick J. Vrba; Richard L. Walker

    2006-11-16

    Trigonometric parallaxes of 16 nearby planetary nebulae are presented, including reduced errors for seven objects with previous initial results and results for six new objects. The median error in the parallax is 0.42 mas, and twelve nebulae have parallax errors less than 20 percent. The parallax for PHL932 is found here to be smaller than was measured by Hipparcos, and this peculiar object is discussed. Comparisons are made with other distance estimates. The distances determined from these parallaxes tend to be intermediate between some short distance estimates and other long estimates; they are somewhat smaller than estimated from spectra of the central stars. Proper motions and tangential velocities are presented. No astrometric perturbations from unresolved close companions are detected.

  5. Cataclysmic variables in the SUPERBLINK proper motion survey

    SciTech Connect (OSTI)

    Skinner, Julie N.; Thorstensen, John R.; Lépine, Sébastien

    2014-12-01

    We have discovered a new high proper motion cataclysmic variable (CV) in the SUPERBLINK proper motion survey, which is sensitive to stars with proper motions greater than 40 mas yr{sup ?1}. This CV was selected for follow-up observations as part of a larger search for CVs selected based on proper motions and their near-UV?V and V?K{sub s} colors. We present spectroscopic observations from the 2.4 m Hiltner Telescope at MDM Observatory. The new CV's orbital period is near 96 minutes, its spectrum shows the double-peaked Balmer emission lines characteristic of quiescent dwarf novae, and its V magnitude is near 18.2. Additionally, we present a full list of known CVs in the SUPERBLINK catalog.

  6. Characterization of polyxylylenes with solid state {sup 13}C nuclear magnetic resonance spectroscopy

    SciTech Connect (OSTI)

    Loy, D.A.; Assink, R.A.; Jamison, G.M.; McNamara, W.F.; Schneider, D.A. [Sandia National Labs., Livermore, CA (United States); Prabakar, S. [New Mexico Univ., Albuquerque, NM (United States)

    1996-02-01

    Polyxylylenes are thermoplastics used as encapsulants for electronic devices. Five polyxylylenes were prepared by pyrolysis of [2.2]paracyclophanes and characterized by solid state {sup 13}C NMR spectroscopy. The chemical shift data, in combination with interrupted decoupling experiments, allowed assignment of resonances to their carbon sources in the polymers. This confirmed the integrity of the xylylene building block in the polymers and is consistent with linear polymers. No crosslinking could be detected within the NMR sensitivity limits. Residual paracyclophane was detected by {sup 13}C CP MAS NMR spectroscopy in the polyxylylene samples prepared at room temperature; however discrete {sup 13}C resonances due to amorphous and crystalline phases in the polymers were not resolved.

  7. Porosity in hexylene-bridged polysilsesquioxanes: Effects of monomer concentration

    SciTech Connect (OSTI)

    Baugher, B.; Loy, D.A.; Assink, R.A. [Sandia National Labs., Albuquerque, NM (United States); Prabakar, S. [Advanced Materials Lab., Albuquerque, NM (United States); Shea, K.J.; Oviatt, H. [California Univ., Irvine, CA (United States). Dept. of Chemistry

    1994-12-31

    Hexylene-bridged polysilsesquioxanes can be prepared as mesoporous or non-porous xerogels simply by switching from basic to acidic polymerization conditions. In this study, we looked at the effect of monomer concentration on porosity of hexylene-bridged xerogels prepared under acidic and basic conditions. 1, 6-Hexylene-bridged polysilsesquioxanes were prepared by sol-gel polymerizations of 1, 6-bis(triethoxysilyl)hexane 1 with concentrations between 0. 1 to 1.2 M in ethanol. Gelation times ranged from seconds for 1.2 M concentration to months for 0.2 M. The gels were processed into xerogels by an aqueous work-up and the dry gels characterized by scanning electron microscopy (SEM), solid state {sup 13}C and {sup 29}Si CP MAS NMR spectroscopy, and gas sorption porosimetry.

  8. Comparison of bridged polysilsesquioxane xerogels prepared from methoxy-, ethoxy-, and propoxy-silyl monomers

    SciTech Connect (OSTI)

    Baugher, B.M.; Loy, D.A. [Sandia National Laboratories, Albuquerque, NM (United States)

    1996-10-01

    Hydrocarbon-bridged polysilsesquioxanes are prepared by the sol-gel polymerization of monomers with more than one trialkoxysilyl groups attached directly to the bridging group by Si-C bonds. While the effects of varying the length of the bridging group (length, rigidity, etc.), monomer concentration, and type of catalyst have been studied, the effect of different alkoxy ligands on the silicon atoms has not been investigated. For this study, 1, 6-bis(triethoxysilyl)hexane 1, 1,6-bis(trimethoxysilyl)hexane 2, and 1,6-bis(tripropoxysilyl)hexane 3 were polymerized under acidic and basic conditions in ethanol, methanol, and n-propanol respectively as well as tetrahydrofuran (THF). The resulting gels were processed to afford xerogels that were characterized by SEM, solid state {sup 13}C and {sup 29}Si Cross Polarization Magic Angle Spinning (CP MAS) NMR spectroscopy, nitrogen and CO{sub 2} sorption porosimetry.

  9. Improvement of thermal properties of low-rank coals treated by hydrothermal process

    SciTech Connect (OSTI)

    Xie, X.F.; Ohki, A.; Maeda, S.

    1999-07-01

    Australian low-rank coals, Loy Yang coal, Yallourn coal and Indonesian Adaro coal are hydrothermally treated at 200-350 C. The simultaneous TG/DTA is used to investigate the thermal properties, which include the volatile release profile under a nitrogen atmosphere and the burning profile under an air atmosphere. It is found that the temperature of volatile matter combustion (Ti1) of the hot water dried coals (upgraded coals) increases with heat treatment temperature (HTT), whereas the temperature of char combustion (Ti2), the temperature of maximum reaction (Tmax) and the temperature of char burn out (Tout) do not have large increase on the HTT. These results suggest that the HWD process can raise the volatile matter ignition temperature, resulting in improving the spontaneous ignition temperature, but it still maintains the original combustion behavior. Results from TG-DTA measurements are consistent with those determined by FTIR and solid state {sup 13}C CP/MAS NMR.

  10. Comparison of bridged polysilsesquioxane xerogels prepared from methoxy- and ethoxy-silyl monomers

    SciTech Connect (OSTI)

    Loy, D.A.; Baugher, B.; Assink, R.A. [Sandia National Labs., Albuquerque, NM (United States); Prabakar, S. [Advanced Materials Lab., Albuquerque, NM (United States); Shea, K.J. [California Univ., Irvine, CA (United States). Dept. of Chemistry

    1994-12-31

    Hydrocarbon-bridged polysilsesquioxanes are prepared by the sol-gel polymerization of monomers with more than one trialkoxysilyl group attached directly to the bridging group by Si-C bonds. While the effects of varying the identity of the bridging group (length, rigidity, etc.), monomer concentration, and type of catalyst have been studied, the effect of different alkoxy ligands on the silicon atoms has not been investigated. For this study, 1, 6-- bis(triethoxysilyl)hexane 1 and 1, 6-bis(trimethoxysilyl)hexane 2 were polymerized under acidic and basic conditions in ethanol and methanol, respectively, and in tetrahydrofuran (THF). The resulting gels were processed to afford xerogels that were characterized by SEM, solid state {sup 13}C and {sup 29}Si Cross Polarization Magic Angle Spinning (CP MAS) NMR spectroscopy, and nitrogen sorption porosimetry.

  11. A Proper Motion Survey Using the First Sky Pass of NEOWISE-Reactivation Data

    E-Print Network [OSTI]

    Schneider, Adam C; Cushing, Michael C; Kirkpatrick, J Davy; Mainzer, Amy; Gelino, Christopher R; Fajardo-Acosta, Sergio B; Bauer, James

    2015-01-01

    The Wide-field Infrared Survey Explorer (WISE) was reactivated in December of 2013 (NEOWISE) to search for potentially hazardous near-Earth objects. We have conducted a survey using the first sky pass of NEOWISE data and the AllWISE catalog to identify nearby stars and brown dwarfs with large proper motions ($\\mu_{\\rm total}$ $\\gtrsim$ 250 mas yr$^{-1}$). A total of 20,548 high proper motion objects were identified, 1,006 of which are new discoveries. This survey has uncovered a significantly larger sample of fainter objects (W2 $\\gtrsim$13 mag) than the previous WISE motion surveys of Luhman (2014a) and Kirkpatrick et al. (2014). Many of these objects are predicted to be new L and T dwarfs based on near- and mid-infrared colors. Using estimated spectral types along with distance estimates, we have identified several objects likely belonging to the nearby Solar neighborhood (d $potentially nea...

  12. Asymmetric silicate dust distribution toward the silicate carbon star BM Gem

    E-Print Network [OSTI]

    Keiichi Ohnaka; Hideyuki Izumiura; Christoph Leinert; Thomas Driebe; Gerd Weigelt; Markus Wittkowski

    2008-07-21

    Silicate carbon stars show the 10 micron silicate emission, despite their carbon-rich photospheres. They are considered to have circumbinary or circum-companion disks, which serve as a reservoir of oxygen-rich material shed by mass loss in the past. We present N-band spectro-interferometric observations of the silicate carbon star BM Gem using MIDI at the Very Large Telescope Interferometer (VLTI). Our aim is to probe the spatial distribution of oxygen-rich dust with high spatial resolution. BM Gem was observed with VLTI/MIDI at 44--62 m baselines using the UT2-UT3 and UT3-UT4 baseline configurations. The N-band visibilities observed for BM Gem show a steep decrease from 8 to ~10 micron and a gradual increase longward of ~10 micron, reflecting the optically thin silicate emission feature emanating from sub-micron-sized amorphous silicate grains. The differential phases obtained at baselines of ~44--46 m show significant non-zero values (~ -70 degrees) in the central part of the silicate emission feature between ~9 and 11 micron, revealing a photocenter shift and the asymmetric nature of the silicate emitting region. The observed N-band visibilities and differential phases can be fairly explained by a simple geometrical model in which the unresolved star is surrounded by a ring with azimuthal brightness modulation. The best-fit model is characterized by a broad ring (~70 mas across at 10 micron) with a bright region which is offset from the unresolved star by ~20 mas at a position angle of ~280 degrees. This model can be interpreted as a system with a circum-companion disk and is consistent with the spectroscopic signatures of an accretion disk around an unseen companion recently discovered in the violet spectrum of BM Gem.

  13. SU-E-I-98: Dose Comparison for Pulmonary Embolism CT Studies: Single Energy Vs. Dual Energy

    SciTech Connect (OSTI)

    Mahmood, U; Erdi, Y

    2014-06-01

    Purpose: The purpose of this study was to assess and compare the size specific dose estimate (SSDE), dose length product (DLP) and noise relationship for pulmonary embolism studies evaluated by single source dual energy computed tomography (DECT) against conventional CT (CCT) studies in a busy cancer center and to determine the dose savings provided by DECT. Methods: An IRB-approved retrospective study was performed to determine the CTDIvol and DLP from a subset of patients scanned with both DECT and CCT over the past five years. We were able to identify 30 breast cancer patients (6 male, 24 female, age range 24 to 81) who had both DECT and CCT studies performed. DECT scans were performed with a GE HD 750 scanner (140/80 kVp, 480 mAs and 40 mm) and CCT scans were performed with a GE Lightspeed 16 slice scanner (120 kVp, 352 mAs, 20 mm). Image noise was measured by placing an ROI and recording the standard deviation of the mean HU along the descending aorta. Results: The average DECT patient size specific dose estimate was to be 14.2 ± 1.7 mGy as compared to 22.4 ± 2.7 mGy from CCT PE studies, which is a 37% reduction in the SSDE. The average DECT DLP was 721.8 ± 84.6 mGy-cm as compared to 981.8 ± 106.1 mGy-cm for CCT, which is a 26% decrease. Compared to CCT the image noise was found to decrease by 19% when using DECT for PE studies. Conclusion: DECT SSDE and DLP measurements indicate dose savings and image noise reduction when compared to CCT. In an environment that heavily debates CT patient doses, this study confirms the effectiveness of DECT in PE imaging.

  14. TWENTY-FIVE SUBARCSECOND BINARIES DISCOVERED BY LUNAR OCCULTATIONS

    SciTech Connect (OSTI)

    Richichi, A.; Fors, O.; Cusano, F.; Moerchen, M.

    2013-09-15

    We report on 25 subarcsecond binaries, detected for the first time by means of lunar occultations in the near-infrared (near-IR) as part of a long-term program using the ISAAC instrument at the ESO Very Large Telescope. The primaries have magnitudes in the range K = 3.8-10.4, and the companions in the range K = 6.4-12.1. The magnitude differences have a median value of 2.8, with the largest being 5.4. The projected separations are in the range 6-748 mas and with a median of 18 mas, or about three times less than the diffraction limit of the telescope. Among our binary detections are a pre-main-sequence star and an enigmatic Mira-like variable previously suspected to have a companion. Additionally, we quote an accurate first-time near-IR detection of a previously known wider binary. We discuss our findings on an individual basis as far as made possible by the available literature, and we examine them from a statistical point of view. We derive a typical frequency of binarity among field stars of Almost-Equal-To 10%, in the resolution and sensitivity range afforded by the technique ( Almost-Equal-To 0.''003 to Almost-Equal-To 0.''5, and K Almost-Equal-To 12 mag, respectively). This is in line with previous results using the same technique but we point out interesting differences that we can trace up to sensitivity, time sampling, and average distance of the targets. Finally, we discuss the prospects for further follow-up studies.

  15. A CATALOG OF NEAR-IR SOURCES FOUND TO BE UNRESOLVED WITH MILLIARCSECOND RESOLUTION

    SciTech Connect (OSTI)

    Richichi, A.; Fors, O.; Cusano, F.; Moerchen, M.

    2012-12-15

    Calibration is one of the long-standing problems in optical interferometric measurements, particularly with long baselines which demand stars with angular sizes on the milliarcsecond scale and no detectable companions. While systems of calibrators have been generally established for the near-infrared in the bright source regime (K {approx}< 3 mag), modern large interferometers are sensitive to significantly fainter magnitudes. We aim to provide a list of sources found to be unresolved from direct observations with high angular resolution and dynamic range, which can be used to choose interferometric calibrators. To this purpose, we have used a large number of lunar occultations recorded with the ISAAC instrument at the Very Large Telescope to select sources found to be unresolved and without close companions. An algorithm has been used to determine the limiting angular resolution achieved for each source, taking into account a noise model built from occulted and unocculted portions of the light curves. We have obtained upper limits on the angular sizes of 556 sources, with magnitudes ranging from K{sub s} Almost-Equal-To 4 to 10, with a median of 7.2 mag. The upper limits on possible undetected companions (within Almost-Equal-To 0.''5) range from K{sub s} Almost-Equal-To 8 to 13, with a median of 11.5 mag. One-third of the sources have angular sizes {<=}1 mas, and two-thirds have sizes {<=}2 mas. This list of unresolved sources matches well the capabilities of current large interferometric facilities. We also provide available cross-identifications, magnitudes, spectral types, and other auxiliary information. A fraction of the sources are found to be potentially variable. The list covers parts of the Galactic Bulge and in particular the vicinity of the Galactic Center, where extinction is very significant and traditional lists of calibrators are often insufficient.

  16. SU-E-I-60: The Correct Selection of Pitch and Rotation Time for Optimal CT Scanning : The Big Misconception

    SciTech Connect (OSTI)

    Ranallo, F; Szczykutowicz, T

    2014-06-01

    Purpose: To provide correct guidance in the proper selection of pitch and rotation time for optimal CT imaging with multi-slice scanners. Methods: There exists a widespread misconception concerning the role of pitch in patient dose with modern multi-slice scanners, particularly with the use of mA modulation techniques. We investigated the relationship of pitch and rotation time to image quality, dose, and scan duration, with CT scanners from different manufacturers in a way that clarifies this misconception. This source of this misconception may concern the role of pitch in single slice CT scanners. Results: We found that the image noise and dose are generally independent of the selected effective mAs (mA*time/ pitch) with manual mA technique settings and are generally independent of the selected pitch and /or rotation time with automatic mA modulation techniques. However we did find that on certain scanners the use of a pitch just above 0.5 provided images of equal image noise at a lower dose compared to the use of a pitch just below 1.0. Conclusion: The misconception that the use of a lower pitch over-irradiates patients by wasting dose is clearly false. The use of a lower pitch provides images of equal or better image quality at the same patient dose, whether using manual mA or automatic mA modulation techniques. By decreasing the pitch and the rotation times by equal amounts, both helical and patient motion artifacts can be reduced without affecting the exam time. The use of lower helical pitch also allows better scanning of larger patients by allowing a greater scan effective mAs, if the exam time can be extended. The one caution with the use of low pitch is not related to patient dose, but to the length of the scan time if the rotation time is not set short enough. Partial Research funding from GE HealthCare.

  17. SU-E-I-46: Sample-Size Dependence of Model Observers for Estimating Low-Contrast Detection Performance From CT Images

    SciTech Connect (OSTI)

    Reiser, I; Lu, Z [University of Chicago, Chicago, IL (United States)

    2014-06-01

    Purpose: Recently, task-based assessment of diagnostic CT systems has attracted much attention. Detection task performance can be estimated using human observers, or mathematical observer models. While most models are well established, considerable bias can be introduced when performance is estimated from a limited number of image samples. Thus, the purpose of this work was to assess the effect of sample size on bias and uncertainty of two channelized Hotelling observers and a template-matching observer. Methods: The image data used for this study consisted of 100 signal-present and 100 signal-absent regions-of-interest, which were extracted from CT slices. The experimental conditions included two signal sizes and five different x-ray beam current settings (mAs). Human observer performance for these images was determined in 2-alternative forced choice experiments. These data were provided by the Mayo clinic in Rochester, MN. Detection performance was estimated from three observer models, including channelized Hotelling observers (CHO) with Gabor or Laguerre-Gauss (LG) channels, and a template-matching observer (TM). Different sample sizes were generated by randomly selecting a subset of image pairs, (N=20,40,60,80). Observer performance was quantified as proportion of correct responses (PC). Bias was quantified as the relative difference of PC for 20 and 80 image pairs. Results: For n=100, all observer models predicted human performance across mAs and signal sizes. Bias was 23% for CHO (Gabor), 7% for CHO (LG), and 3% for TM. The relative standard deviation, ?(PC)/PC at N=20 was highest for the TM observer (11%) and lowest for the CHO (Gabor) observer (5%). Conclusion: In order to make image quality assessment feasible in the clinical practice, a statistically efficient observer model, that can predict performance from few samples, is needed. Our results identified two observer models that may be suited for this task.

  18. A Disk of Young Stars at the Galactic Center as Determined by Individual Stellar Orbits

    E-Print Network [OSTI]

    J. R. Lu; A. M. Ghez; S. D. Hornstein; M. R. Morris; E. E. Becklin; K. Matthews

    2008-08-28

    We present new proper motions from the 10 m Keck telescopes for a puzzling population of massive, young stars located within 3.5" (0.14 pc) of the supermassive black hole at the Galactic Center. Our proper motion measurements have uncertainties of only 0.07 mas/yr (3 km/s), which is ~7 times better than previous proper motion measurements for these stars, and enables us to measure accelerations as low as 0.2 mas/yr^2 (7 km/s/yr). Using these measurements, line-of-sight velocities from the literature, and 3D velocities for additional young stars in the central parsec, we constrain the true orbit of each individual star and directly test the hypothesis that the massive stars reside in two stellar disks as has been previously proposed. Analysis of the stellar orbits reveals only one of the previously proposed disks of young stars using a method that is capable of detecting disks containing at least 7 stars. The detected disk contains 50% of the young stars, is inclined by ~115 deg from the plane of the sky, and is oriented at a position angle of ~100 deg East of North. Additionally, the on-disk and off-disk populations have similar K-band luminosity functions and radial distributions that decrease at larger projected radii as \\propto r^-2. The disk has an out-of-the-disk velocity dispersion of 28 +/- 6 km/s, which corresponds to a half-opening angle of 7 +/- 2 deg, and several candidate disk members have eccentricities greater than 0.2. Our findings suggest that the young stars may have formed in situ but in a more complex geometry than a simple, thin circular disk.

  19. The proper motion of the Arches cluster with Keck Laser-Guide Star Adaptive Optics

    E-Print Network [OSTI]

    Andrea Stolte; Andrea M. Ghez; Mark Morris; Jessica R. Lu; Wolfgang Brandner; Keith Matthews

    2007-11-21

    We present the first measurement of the proper motion of the young, compact Arches cluster near the Galactic center from near-infrared adaptive optics (AO) data taken with the recently commissioned laser-guide star (LGS) at the Keck 10-m telescope. The excellent astrometric accuracy achieved with LGS-AO provides the basis for a detailed comparison with VLT/NAOS-CONICA data taken 4.3 years earlier. Over the 4.3 year baseline, a spatial displacement of the Arches cluster with respect to the field population is measured to be 24.0 +/- 2.2 mas, corresponding to a proper motion of 5.6 +/- 0.5 mas/yr or 212 +/- 29 km/s at a distance of 8 kpc. In combination with the known line-of-sight velocity of the cluster, we derive a 3D space motion of 232 +/- 30 km/s of the Arches relative to the field. The large proper motion of the Arches cannot be explained with any of the closed orbital families observed in gas clouds in the bar potential of the inner Galaxy, but would be consistent with the Arches being on a transitional trajectory from x1 to x2 orbits. We investigate a cloud-cloud collision as the possible origin for the Arches cluster. The integration of the cluster orbit in the potential of the inner Galaxy suggests that the cluster passes within 10 pc of the supermassive black hole only if its true GC distance is very close to its projected distance. A contribution of young stars from the Arches cluster to the young stellar population in the inner few parsecs of the GC thus appears increasingly unlikely. The measurement of the 3D velocity and orbital analysis provides the first observational evidence that Arches-like clusters do not spiral into the GC. This confirms that no progenitor clusters to the nuclear cluster are observed at the present epoch.

  20. TH-A-18C-03: Noise Correlation in CBCT Projection Data and Its Application for Noise Reduction in Low-Dose CBCT

    SciTech Connect (OSTI)

    ZHANG, H; Huang, J; Ma, J; Chen, W; Ouyang, L; Wang, J

    2014-06-15

    Purpose: To study the noise correlation properties of cone-beam CT (CBCT) projection data and to incorporate the noise correlation information to a statistics-based projection restoration algorithm for noise reduction in low-dose CBCT. Methods: In this study, we systematically investigated the noise correlation properties among detector bins of CBCT projection data by analyzing repeated projection measurements. The measurements were performed on a TrueBeam on-board CBCT imaging system with a 4030CB flat panel detector. An anthropomorphic male pelvis phantom was used to acquire 500 repeated projection data at six different dose levels from 0.1 mAs to 1.6 mAs per projection at three fixed angles. To minimize the influence of the lag effect, lag correction was performed on the consecutively acquired projection data. The noise correlation coefficient between detector bin pairs was calculated from the corrected projection data. The noise correlation among CBCT projection data was then incorporated into the covariance matrix of the penalized weighted least-squares (PWLS) criterion for noise reduction of low-dose CBCT. Results: The analyses of the repeated measurements show that noise correlation coefficients are non-zero between the nearest neighboring bins of CBCT projection data. The average noise correlation coefficients for the first- and second- order neighbors are about 0.20 and 0.06, respectively. The noise correlation coefficients are independent of the dose level. Reconstruction of the pelvis phantom shows that the PWLS criterion with consideration of noise correlation (PWLS-Cor) results in a lower noise level as compared to the PWLS criterion without considering the noise correlation (PWLS-Dia) at the matched resolution. Conclusion: Noise is correlated among nearest neighboring detector bins of CBCT projection data. An accurate noise model of CBCT projection data can improve the performance of the statistics-based projection restoration algorithm for low-dose CBCT.

  1. Investigation of the hydrothermal crystallisation of the perovskite solid solution NaCe{sub 1?x}La{sub x}Ti{sub 2}O{sub 6} and its defect chemistry

    SciTech Connect (OSTI)

    Harunsani, Mohammad H.; Woodward, David I.; Peel, Martin D.; Ashbrook, Sharon E.; Walton, Richard I.

    2013-11-15

    Perovskites of nominal composition NaCe{sub 1?x}La{sub x}Ti{sub 2}O{sub 6} (0?x?1) crystallise directly under hydrothermal conditions at 240 °C. Raman spectroscopy shows distortion from the ideal cubic structure and Rietveld analysis of powder X-ray and neutron diffraction reveals that the materials represent a continuous series in rhombohedral space group R3-bar c. Ce L{sub III}-edge X-ray absorption near edge structure spectroscopy shows that while the majority of cerium is present as Ce{sup 3+} there is evidence for Ce{sup 4+}. The paramagnetic Ce{sup 3+} affects the chemical shift and line width of {sup 23}Na MAS NMR spectra, which also show with no evidence for A-site ordering. {sup 2}H MAS NMR of samples prepared in D{sub 2}O shows the inclusion of deuterium, which IR spectroscopy shows is most likely to be as D{sub 2}O. The deuterium content is highest for the cerium-rich materials, consistent with oxidation of some cerium to Ce{sup 4+} to provide charge balance of A-site water. - Graphical abstract: A multi-element A-site perovskite crystallises directly from aqueous, basic solutions at 240 °C; while the paramagnetic effect of Ce{sup 3+} on the {sup 23}Na NMR shows a homogeneous solid-solution, the incorporation of A-site water is also found from {sup 2}H NMR and IR, with oxidation of some cerium to charge balance proved by XANES spectroscopy. Display Omitted - Highlights: • Direct hydrothermal synthesis allows crystallisation of a perovskite solid-solution. • XANES spectroscopy shows some oxidation of Ce{sup 3+} to Ce{sup 4+}. • The paramagnetism of Ce{sup 3+} shifts and broadens the {sup 23}Na solid-state NMR. • The perovskite materials incorporate water as an A-site defect.

  2. A PROPER MOTION STUDY OF THE HARO 6-10 OUTFLOW: EVIDENCE FOR A SUBARCSECOND BINARY

    SciTech Connect (OSTI)

    Wilking, Bruce A.; Gerling, Bradley M.; Gibb, Erika; Marvel, Kevin B.; Claussen, Mark J.; Wootten, Alwyn E-mail: bmg5333@truman.edu E-mail: marvel@aas.org E-mail: awootten@nrao.edu

    2012-07-10

    We present single-dish and very long baseline interferometry observations of an outburst of water maser emission from the young binary system Haro 6-10. Haro 6-10 lies in the Taurus molecular cloud and contains a visible T Tauri star with an infrared companion 1.''3 north. Using the Very Long Baseline Array, we obtained five observations spanning three months and derived absolute positions for 20 distinct maser spots. Three of the masers can be traced over three or more epochs, enabling us to extract absolute proper motions and tangential velocities. We deduce that the masers represent one side of a bipolar outflow that lies nearly in the plane of the sky with an opening angle of {approx}45 Degree-Sign . They are located within 50 mas of the southern component of the binary, the visible T Tauri star Haro 6-10S. The mean position angle on the sky of the maser proper motions ({approx}220 Degree-Sign ) suggests they are related to the previously observed giant Herbig-Haro (HH) flow which includes HH 410, HH 411, HH 412, and HH 184A-E. A previously observed HH jet and extended radio continuum emission (mean position angle of {approx}190 Degree-Sign ) must also originate in the vicinity of Haro 6-10S and represent a second, distinct outflow in this region. We propose that a yet unobserved companion within 150 mas of Haro 6-10S is responsible for the giant HH/maser outflow while the visible star is associated with the HH jet. Despite the presence of H{sub 2} emission in the spectrum of the northern component of the binary, Haro 6-10N, none of outflows/jets can be tied directly to this young stellar object.

  3. A parallax distance to the microquasar GRS 1915+105 and a revised estimate of its black hole mass

    SciTech Connect (OSTI)

    Reid, M. J.; McClintock, J. E.; Steiner, J. F.; Narayan, R.; Steeghs, D.; Remillard, R. A.; Dhawan, V.

    2014-11-20

    Using the Very Long Baseline Array, we have measured a trigonometric parallax for the microquasar GRS 1915+105, which contains a black hole and a K-giant companion. This yields a direct distance estimate of 8.6{sub ?1.6}{sup +2.0} kpc and a revised estimate for the mass of the black hole of 12.4{sub ?1.8}{sup +2.0} M {sub ?}. GRS 1915+105 is at about the same distance as some H II regions and water masers associated with high-mass star formation in the Sagittarius spiral arm of the Galaxy. The absolute proper motion of GRS 1915+105 is –3.19 ± 0.03 mas yr{sup –1} and –6.24 ± 0.05 mas yr{sup –1} toward the east and north, respectively, which corresponds to a modest peculiar speed of 22 ± 24 km s{sup –1} at the parallax distance, suggesting that the binary did not receive a large velocity kick when the black hole formed. On one observational epoch, GRS 1915+105 displayed superluminal motion along the direction of its approaching jet. Considering previous observations of jet motions, the jet in GRS 1915+105 can be modeled with a jet inclination to the line of sight of 60° ± 5° and a variable flow speed between 0.65c and 0.81c, which possibly indicates deceleration of the jet at distances from the black hole ? 2000 AU. Finally, using our measurements of distance and estimates of black hole mass and inclination, we provisionally confirm our earlier result that the black hole is spinning very rapidly.

  4. VLBI Imaging of Luminous Infrared Galaxies: AGN Cores in Mrk231, UGC 5101 & NGC 7469

    E-Print Network [OSTI]

    Carol J. Lonsdale; Colin J. Lonsdale; Harding E. Smith; Philip J. Diamond

    2003-04-17

    We report 18cm VLBI continuum imaging observations at 5 mas resolution for UGC 5101, NGC 7469, and Mrk 231, all part of a sample of Luminous Infrared Galaxies which have been shown to have strong VLBI radio cores. The radio morphology of these three systems on VLBI scales is AGN-like, with well-defined ridgelines and high-brightness yet spatially resolved components. The structure and flux densities of these VLBI components are not consistent with starburst generated radio supernovae of the type found in Arp 220. On scales of 100pc the radio continuum in all three objects appears to be dominated by an AGN, not a starburst. Radio emission on larger scales may well originate in a less compact circumnuclear star-forming region. Confirming and extending VLBI imaging of Mrk 231 by Ulvestad et al. (1999), our continuum image shows a triple structure, with a core and two lobes, classifying it as a Compact Symmetric Object (CS0). If the southern (primary) lobe/hot-spot in Mrk 231 is confined by ram pressure, we estimate a lobe advance speed, $v_a \\sim 10^{-4}c$, and an age for the jet/compact source, $< 10^6 yr$. We have also imaged the 1667 MHz OH maser emission in Mrk 231, which is extended on scales of 50--100 milliarcsec (40--80 pc) and probably coincides with the inner region of the disk which is seen in CO emission and HI absorption. Among OH megamasers studied at high sensitivity with mas resolution, Mrk 231 is unique in the stringent upper limits placed upon the flux density of compact OH structures of the type found in Arp 220 and other LIGs. It is possible that the circumnuclear environment of Mrk 231 has been sufficiently disrupted by the emergent QSO that the cool, dense clouds necessary for such compact masers no longer exist.

  5. DISTANCE AND PROPER MOTION MEASUREMENT OF THE RED SUPERGIANT, PZ CAS, IN VERY LONG BASELINE INTERFEROMETRY H{sub 2}O MASER ASTROMETRY

    SciTech Connect (OSTI)

    Kusuno, K.; Asaki, Y. [Department of Space and Astronautical Science, School of Physical Sciences, Graduate University for Advanced Studies (SOKENDAI), 3-1-1 Yoshinodai, Chuou-Ku, Sagamihara, Kanagawa 252-5210 (Japan); Imai, H. [Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan); Oyama, T., E-mail: kusuno@vsop.isas.jaxa.jp, E-mail: asaki@vsop.isas.jaxa.jp, E-mail: hiroimai@sci.kagoshima-u.ac.jp, E-mail: t.oyama@nao.ac.jp [Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2013-09-10

    We present the very long baseline interferometry H{sub 2}O maser monitoring observations of the red supergiant, PZ Cas, at 12 epochs from 2006 April to 2008 May. We fitted maser motions to a simple model composed of a common annual parallax and linear motions of the individual masers. The maser motions with the parallax subtracted were well modeled by a combination of a common stellar proper motion and a radial expansion motion of the circumstellar envelope. We obtained an annual parallax of 0.356 {+-} 0.026 mas and a stellar proper motion of {mu}{sub {alpha}}{sup *} cos {delta} = -3.7 {+-} 0.2 and {mu}{sup *}{sub {delta}}=-2.0{+-}0.3 mas yr{sup -1} eastward and northward, respectively. The annual parallax corresponds to a trigonometric parallax of 2.81{sup +0.22}{sub -0.19} kpc. By rescaling the luminosity of PZ Cas in any previous studies using our trigonometric parallax, we estimated the location of PZ Cas on a Hertzsprung-Russell diagram and found that it approaches a theoretically evolutionary track around an initial mass of {approx}25 M{sub Sun }. The sky position and the distance to PZ Cas are consistent with the OB association, Cas OB5, which is located in a molecular gas super shell. The proper motion of PZ Cas is close to that of the OB stars and other red supergiants in Cas OB5 measured by the Hipparcos satellite. We derived the peculiar motion of PZ Cas of U{sub s} = 22.8 {+-} 1.5, V{sub s} = 7.1 {+-} 4.4, and W{sub s} = -5.7 {+-} 4.4 km s{sup -1}. This peculiar motion has rather a large U{sub s} component, unlike those of near high-mass star-forming regions with negatively large V{sub s} motions. The uniform proper motions of the Cas OB5 member stars suggest random motions of giant molecular clouds moving into local potential minima in a time-dependent spiral arm, rather than a velocity field caused by the spiral arm density wave.

  6. Stellar Orbits Around the Galactic Center Black Hole

    E-Print Network [OSTI]

    A. M. Ghez; S. Salim; S. D. Hornstein; A. Tanner; J. R. Lu; M. Morris; E. E. Becklin; G. Duchene

    2004-11-02

    We present new proper motion measurements and simultaneous orbital solutions for three newly identified (S0-16, S0-19, and S0-20) and four previously known (S0-1, S0-2, S0-4, and S0-5) stars at the Galactic Center. This analysis pinpoints the Galaxy's central dark mass to within +-1 milli-arcsec and, for the first time from orbital dynamics, limits its proper motion to 1.5+-0.5 mas/y, which is consistent with our derivation of the position of Sgr A* in the infrared reference frame (+-10 mas). The estimated central dark mass from orbital motions is 3.7 (+-0.2) x 10^6 (Ro/8kpc)^3 Mo; this is a more direct measure of mass than those obtained from velocity dispersion measurements, which are as much as a factor of two smaller. The smallest closest approach is achieved by S0-16, which confines the mass to within a radius of a mere 45 AU and increases the inferred dark mass density by four orders of magnitude compared to earlier analyses based on velocity and acceleration vectors, making the Milky Way the strongest existing case by far for a supermassive black hole at the center of any normal type galaxy. The stellar orbital properties suggest that the distributions of eccentricities and angular momentum vector and apoapse directions are consistent with those of an isotropic system. Therefore many of the mechanisms proposed for the formation of young stars in the vicinity of a supermassive black hole, such as formation from a pre-existing disk, are unlikely solutions for the Sgr A* cluster stars. Unfortunately, all existing alternative theories are also somewhat problematic. Understanding the apparent youth of stars in the Sgr A* cluster, as well as the more distant He I emission line stars, has now become one of the major outstanding issues in the study of the Galactic Center.

  7. THE HAWAII INFRARED PARALLAX PROGRAM. I. ULTRACOOL BINARIES AND THE L/T TRANSITION

    SciTech Connect (OSTI)

    Dupuy, Trent J.; Liu, Michael C.

    2012-08-01

    We present the first results from our high-precision infrared (IR) astrometry program at the Canada-France-Hawaii Telescope. We measure parallaxes for 83 ultracool dwarfs (spectral types M6-T9) in 49 systems, with a median uncertainty of 1.1 mas (2.3%) and as good as 0.7 mas (0.8%). We provide the first parallaxes for 48 objects in 29 systems, and for another 27 objects in 17 systems, we significantly improve upon published results, with a median (best) improvement of 1.7 times (5 times). Three systems show astrometric perturbations indicative of orbital motion; two are known binaries (2MASS J0518-2828AB and 2MASS J1404-3159AB) and one is spectrally peculiar (SDSS J0805+4812). In addition, we present here a large set of Keck adaptive optics imaging that more than triples the number of binaries with L6-T5 components that have both multi-band photometry and distances. Our data enable an unprecedented look at the photometric properties of brown dwarfs as they cool through the L/T transition. Going from Almost-Equal-To L8 to Almost-Equal-To T4.5, flux in the Y and J bands increases by Almost-Equal-To 0.7 mag and Almost-Equal-To 0.5 mag, respectively (the Y- and J-band 'bumps'), while flux in the H, K, and L' bands declines monotonically. This wavelength dependence is consistent with cloud clearing over a narrow range of temperature, since condensate opacity is expected to dominate at 1.0-1.3 {mu}m. Interestingly, despite more than doubling the near-IR census of L/T transition objects, we find a conspicuous paucity of objects on the color-magnitude diagram just blueward of the late-L/early-T sequence. This 'L/T gap' occurs at (J - H){sub MKO} 0.1-0.3 mag, (J - K){sub MKO} = 0.0-0.4 mag, and implies that the last phases of cloud evolution occur rapidly. Finally, we provide a comprehensive update to the absolute magnitudes of ultracool dwarfs as a function of spectral type using a combined sample of 314 objects.

  8. Mechanochemical-thermal preparation and structural studies of mullite-type Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9} solid solutions

    SciTech Connect (OSTI)

    Da Silva, K.L. [Institute of Physical and Theoretical Chemistry, Technische Universitaet Braunschweig, Hans-Sommer-Str. 10, 38106 Braunschweig (Germany); Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3a, 30167 Hannover (Germany); Department of Physics, State University of Maringa, Av. Colombo 5790, 87020-900 Maringa (Brazil); Sepelak, V., E-mail: vladimir.sepelak@kit.ed [Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Duevel, A. [Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3a, 30167 Hannover (Germany); Paesano, A. [Department of Physics, State University of Maringa, Av. Colombo 5790, 87020-900 Maringa (Brazil); Hahn, H. [Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Litterst, F.J. [Institute of Condensed Matter Physics, Technische Universitaet Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig (Germany); Heitjans, P. [Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3a, 30167 Hannover (Germany); Becker, K.D. [Institute of Physical and Theoretical Chemistry, Technische Universitaet Braunschweig, Hans-Sommer-Str. 10, 38106 Braunschweig (Germany)

    2011-05-15

    A series of Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9} solid solutions (0{<=}x{<=}1), prepared by mechanochemical processing of Bi{sub 2}O{sub 3}/Ga{sub 2}O{sub 3}/Al{sub 2}O{sub 3} mixtures and subsequent annealing, was investigated by XRD, EDX, and {sup 27}Al MAS NMR. The structure of the Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9} solid solutions is found to be orthorhombic, space group Pbam (No. 55). The lattice parameters of the Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9} series increase linearly with increasing gallium content. Rietveld refinement of the XRD data as well as the analysis of the {sup 27}Al MAS NMR spectra show a preference of gallium cations for the tetrahedral sites in Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9}. As a consequence, this leads to a far from random distribution of Al and Ga cations across the whole series of solid solutions. -- Graphical Abstract: Mullite-type Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9} mixed crystals (0{<=}x{<=}1) prepared by a combined mechanochemical-thermal route possess a non-random distribution of Ga{sup 3+} and Al{sup 3+} cations over the sites of tetrahedral (T) and octahedral [O] coordination, characterized by the preference of Ga{sup 3+} (Al{sup 3+}) for tetrahedral (octahedral) sites. Display Omitted Highlights: {yields} Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9} (0{<=}x{<=}1) were synthesized via mechanochemical-thermal route. {yields} The lattice parameters of Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9} increase linearly with gallium content. {yields} Quantitative information on the cation distribution in Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9} is derived. {yields} Ga{sup 3+} and Al{sup 3+} show the preference for tetrahedral and octahedral sites, respectively.

  9. SU-E-J-214: Comparative Assessment On IGRT On Partial Bladder Cancer Treatment Between CT-On-Rails (CTOR) and KV Cone Beam CT (CBCT)

    SciTech Connect (OSTI)

    Lin, T; Ma, C

    2014-06-01

    Purpose: Image-Guided radiation therapy(IGRT) depends on reliable online patient-specific anatomy information to address random and progressive anatomy changes. Large margins have been suggested to bladder cancer treatment due to large daily bladder anatomy variation. KV Cone beam CT(CBCT) has been used in IGRT localization prevalently; however, its lack of soft tissue contrast makes clinicians hesitate to perform daily soft tissue alignment with CBCT for partial bladder cancer treatment. This study compares the localization uncertainties of bladder cancer IGRT using CTon- Rails(CTOR) and CBCT. Methods: Three T2N0M0 bladder cancer patients (total of 66 Gy to partial bladder alone) were localized daily with either CTOR or CBCT for their entire treatment course. A total of 71 sets of CTOR and 22 sets of CBCT images were acquired and registered with original planning CT scans by radiation therapists and approved by radiation oncologists for the daily treatment. CTOR scanning entailed 2mm slice thickness, 0.98mm axial voxel size, 120kVp and 240mAs. CBCT used a half fan pelvis protocol from Varian OBI system with 2mm slice thickness, 0.98axial voxel size, 125kVp, and 680mAs. Daily localization distribution was compared. Accuracy of CTOR and CBCT on partial bladder alignment was also evaluated by comparing bladder PTV coverage. Results: 1cm all around PTV margins were used in every patient except target superior limit margin to 0mm due to bowel constraint. Daily shifts on CTOR averaged to 0.48, 0.24, 0.19 mms(SI,Lat,AP directions); CBCT averaged to 0.43, 0.09, 0.19 mms(SI,Lat,AP directions). The CTOR daily localization showed superior results of V100% of PTV(102% CTOR vs. 89% CBCT) and bowel(Dmax 69.5Gy vs. 78Gy CBCT). CTOR images showed much higher contrast on bladder PTV alignment. Conclusion: CTOR daily localization for IGRT is more dosimetrically beneficial for partial bladder cancer treatment than kV CBCT localization and provided better soft tissue PTV identification.

  10. Trigonometric Parallaxes for Two Late-Type Subdwarfs: LSR1425+71 (sdM8.0) and the Binary LSR1610-00 (sd?M6pec)

    E-Print Network [OSTI]

    C. C. Dahn; H. C. Harris; S. E. Levine; T. Tilleman; A. K. B. Monet; R. C. Stone; H. H. Guetter; B. Canzian; J. R. Pier; W. I. Hartkopf; J. Liebert; M. Cushing

    2008-06-13

    Trigonometric parallax astrometry and BVI photometry are presented for two late-type subdwarf candidates, LSR1425+71 (sdM8.0) and LSR1610-00 (sd?M6pec). For the former we measure an absolute parallax of 13.37+/-0.51 mas yielding Mv=15.25+/-0.09. The astrometry for LSR1610-00 shows that this object is an astrometric binary with a period of 1.66+/-0.01 yr. The photocentric orbit is derived from the data; it has a moderate eccentricity (e ~ 0.44+/-0.02) and a semi-major axis of 0.28+/-0.01 AU based on our measured absolute parallax of 31.02+/-0.26 mas. Our radial velocity measure of -108.1+/-1.6 km/s for LSR1610-00 at epoch 2006.179, when coupled with the observation of -95+/-1 km/s at epoch 2005.167 by Reiners & Basri, indicates a systemic radial velocity of -101+/-1 km/s for the LSR1610-00AB pair. The galactic velocity components for LSR1425+71 and LSR1610-00AB -- (U,V,W)=(84+/-6, -202+/-13, 66+/-14) km/s and (U,V,W)=(36+/-2, -232+/-2, -61+/-2) km/s, respectively. For both stars, the velocities are characteristic of halo population kinematics. However, modeling shows that both stars have orbits around the galaxy with high eccentricity that pass remarkably close to the galactic center. LSR1425+71 has a luminosity and colors consistent with its metal-poor subdwarf spectral classification, while LSR1610-00 has a luminosity and most colors indicative of being only mildly metal-poor, plus a uniquely red B-V color. The companion to LSR1610-00 must be a low-mass, substellar brown dwarf. We speculate on the paradoxical nature of LSR1610-00 and possible sources of its peculiarities.

  11. A technique to derive improved proper motions for Kepler objects of interest

    SciTech Connect (OSTI)

    Benedict, G. Fritz [McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Tanner, Angelle M. [Department of Physics and Astronomy, Mississippi State University, Starkville, MS 39762 (United States); Cargile, Phillip A. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Ciardi, David R., E-mail: fritz@astro.as.utexas.edu [NASA Exoplanet Science Institute, Caltech, Pasadena, CA 91125 (United States)

    2014-12-01

    We outline an approach yielding proper motions with higher precision than exists in present catalogs for a sample of stars in the Kepler field. To increase proper-motion precision, we combine first-moment centroids of Kepler pixel data from a single season with existing catalog positions and proper motions. We use this astrometry to produce improved reduced-proper-motion diagrams, analogous to a Hertzsprung-Russell (H-R) diagram, for stars identified as Kepler objects of interest. The more precise the relative proper motions, the better the discrimination between stellar luminosity classes. Using UCAC4 and PPMXL epoch 2000 positions (and proper motions from those catalogs as quasi-Bayesian priors), astrometry for a single test Channel (21) and Season (0) spanning 2 yr yields proper motions with an average per-coordinate proper-motion error of 1.0 mas yr{sup –1}, which is over a factor of three better than existing catalogs. We apply a mapping between a reduced-proper-motion diagram and an H-R diagram, both constructed using Hubble Space Telescope parallaxes and proper motions, to estimate Kepler object of interest K-band absolute magnitudes. The techniques discussed apply to any future small-field astrometry as well as to the rest of the Kepler field.

  12. An investigation of the role of water on retrograde/condensation reactions and enhanced liquefaction yields

    SciTech Connect (OSTI)

    Miknis, F.P.

    1993-01-01

    The overall objectives of this work are to conduct research that will provide the basis for an improved liquefaction process, and to facilitate our understanding of those processes that occur when coals are initially dissolved. Changes in coal structure that occur during coal drying and steam pretreatments will be measured in order to determine what effect water has on retrograde/condensation reactions, and to determine the mechanism by which water enhances coal reactivity toward liquefaction. Different methods for coal drying wig be investigated to determine if drying can be accomplished without destroying coal reactivity toward liquefaction, thereby making coal drying a relatively economical and efficient method for coal pretreatment. Coal drying methods will include conventional thermal drying, microwave drying, and chemical drying at low temperature. State-of-the-art solid-state nuclear magnetic resonance (NMR) techniques using combined rotation and multiple pulse spectroscopy (CRAMPS) and cross polarization with magic-angle spinning (CP/MAS) will be employed: (1) to measures changes in coal structure brought about by the different methods of drying and by low temperature oxidation, and (2) to obtain direct measurements of changes in the aromatic hydrogen-to-carbon ratio of the solid/semisolid material formed or remaining during pretreatment and the initial stages of liquefaction.

  13. An investigation of the role of water on retrograde/condensation reactions and enhanced liquefaction yields. Quarterly progress report, October 1, 1992--December 31, 1992

    SciTech Connect (OSTI)

    Miknis, F.P.

    1993-01-01

    The overall objectives of this work are to conduct research that will provide the basis for an improved liquefaction process, and to facilitate our understanding of those processes that occur when coals are initially dissolved. Changes in coal structure that occur during coal drying and steam pretreatments will be measured in order to determine what effect water has on retrograde/condensation reactions, and to determine the mechanism by which water enhances coal reactivity toward liquefaction. Different methods for coal drying wig be investigated to determine if drying can be accomplished without destroying coal reactivity toward liquefaction, thereby making coal drying a relatively economical and efficient method for coal pretreatment. Coal drying methods will include conventional thermal drying, microwave drying, and chemical drying at low temperature. State-of-the-art solid-state nuclear magnetic resonance (NMR) techniques using combined rotation and multiple pulse spectroscopy (CRAMPS) and cross polarization with magic-angle spinning (CP/MAS) will be employed: (1) to measures changes in coal structure brought about by the different methods of drying and by low temperature oxidation, and (2) to obtain direct measurements of changes in the aromatic hydrogen-to-carbon ratio of the solid/semisolid material formed or remaining during pretreatment and the initial stages of liquefaction.

  14. The environment of the fast rotating star Achernar - Thermal infrared interferometry with VLTI/MIDI and SIMECA modeling

    E-Print Network [OSTI]

    Pierre Kervella; Armando Domiciano De Souza; Samer Kanaan; Anthony Meilland; Alain Spang; Philippe Stee

    2008-12-13

    Context: As is the case of several other Be stars, Achernar is surrounded by an envelope, recently detected by near-IR interferometry. Aims: We search for the signature of circumstellar emission at distances of a few stellar radii from Achernar, in the thermal IR domain. Methods: We obtained interferometric observations on three VLTI baselines in the N band (8-13 mic), using the MIDI instrument. Results: From the measured visibilities, we derive the angular extension and flux contribution of the N band circumstellar emission in the polar direction of Achernar. The interferometrically resolved polar envelope contributes 13.4 +/- 2.5 % of the photospheric flux in the N band, with a full width at half maximum of 9.9 +/- 2.3 mas (~ 6 Rstar). This flux contribution is in good agreement with the photometric IR excess of 10-20% measured by fitting the spectral energy distribution. Due to our limited azimuth coverage, we can only establish an upper limit of 5-10% for the equatorial envelope. We compare the observed properties of the envelope with an existing model of this star computed with the SIMECA code. Conclusions: The observed extended emission in the thermal IR along the polar direction of Achernar is well reproduced by the existing SIMECA model. Already detected at 2.2mic, this polar envelope is most probably an observational signature of the fast wind ejected by the hot polar caps of the star.

  15. Full Three Dimensional Orbits For Multiple Stars on Close Approaches to the Central Supermassive Black Hole

    E-Print Network [OSTI]

    Ghez, A M; Duchêne, G; Hornstein, S D; Morris, M; Salim, S; Tanner, A

    2003-01-01

    With the advent of adaptive optics on the W. M. Keck 10 m telescope, two significant steps forward have been taken in building the case for a supermassive black hole at the center of the Milky Way and understanding the black hole's effect on its environment. Using adaptive optics and speckle imaging to study the motions of stars in the plane of sky with +-~2 mas precision over the past 7 years, we have obtained the first simultaneous orbital solution for multiple stars. Among the included stars, three are newly identified (S0-16, S0-19, S0-20). The most dramatic orbit is that of the newly identified star S0-16, which passed a mere 60 AU from the central dark mass at a velocity of 9,000 km/s in 1999. The orbital analysis results in a new central dark mass estimate of 3.6(+-0.4)x10^6(D/8kpc)^3 Mo. This dramatically strengthens the case for a black hole at the center of our Galaxy, by confining the dark matter to within a radius of 0.0003 pc or 1,000 Rsh and thereby increasing the inferred dark mass density by f...

  16. Limits on the Short Term Variability of Sagittarius A* in the Near-Infrared

    E-Print Network [OSTI]

    Hornstein, S D; Tanner, A; Morris, M; Becklin, E E; Wizinowich, P

    2002-01-01

    The recent detection of a 3-hr X-ray flare by the Chandra Observatory has raised the possibility of enhanced emission over a broad range of wavelengths from Sgr A*, the suspected 2.6 x 10^6 solar mass black hole at the Galactic Center, during a flaring event. We have, therefore, reconstructed 3-hr data sets from 2 micron speckle and adaptive optics images (theta_core = 50 - 100 mas) obtained with the W. M. Keck 10-m telescopes between 1995 and 2001. In 25 separate observations, no evidence of any significant excess emission associated with Sgr A* was detected. The lowest of our detection limits gives an observed limit for the quiescent state of Sgr A* of 0.09+/-0.005 mJy, or, equivalently, a dereddened value of 2.0+/-0.1 mJy, which is a factor of 2 lower than the best previously published quiescent value. Under the assumption that there are random 3-hr flares producing both enhanced X-ray and near-infrared emission, our highest limit constrains the variable state of Sgr A* to <0.8 mJy (observed) or 19 mJy ...

  17. Influence of the ambient solar wind flow on the propagation behavior of interplanetary CMEs

    E-Print Network [OSTI]

    Temmer, Manuela; Möstl, Christian; Veronig, Astrid M; Vrsnak, Bojan; Odstrcil, Dusan

    2011-01-01

    We study three CME/ICME events (2008 June 1-6, 2009 February 13-18, 2010 April 3-5) tracked from Sun to 1 AU in remote-sensing observations of STEREO Heliospheric Imagers and in situ plasma and magnetic field measurements. We focus on the ICME propagation in IP space that is governed by two forces, the propelling Lorentz force and the drag force. We address the question at which heliospheric distance range the drag becomes dominant and the CME gets adjusted to the solar wind flow. To this aim we analyze speed differences between ICMEs and the ambient solar wind flow as function of distance. The evolution of the ambient solar wind flow is derived from ENLIL 3D MHD model runs using different solar wind models, namely Wang-Sheeley-Arge (WSA) and MHD-Around-A-Sphere (MAS). Comparing the measured CME kinematics with the solar wind models we find that the CME speed gets adjusted to the solar wind speed at very different heliospheric distances in the three events under study: from below 30 Rs, to beyond 1 AU, depend...

  18. HIGH VELOCITY PRECESSING JETS FROM THE WATER FOUNTAIN IRAS 18286-0959 REVEALED BY VERY LONG BASELINE ARRAY OBSERVATIONS

    SciTech Connect (OSTI)

    Yung, Bosco H. K.; Nakashima, Jun-ichi; Kwok, Sun [Department of Physics, University of Hong Kong, Pokfulam Rd., Hong Kong (Hong Kong); Imai, Hiroshi [Graduate School of Science and Engineering, Kagoshima University, Kagoshima 890-0065 (Japan); Deguchi, Shuji [Nobeyama Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Diamond, Philip J. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, University of Manchester, Manchester M13 9PL (United Kingdom)

    2011-11-10

    We report the results of multi-epoch Very Long Baseline Array observations of the 22.2 GHz H{sub 2}O maser emission associated with the 'water fountain' IRAS 18286-0959. We suggest that this object is the second example of a highly collimated bipolar precessing outflow traced by H{sub 2}O maser emission, the other is W 43A. The detected H{sub 2}O emission peaks are distributed over a velocity range from -50 km s{sup -1} to 150 km s{sup -1}. The spatial distribution of over 70% of the identified maser features is found to be highly collimated along a spiral jet (jet 1) extended southeast to northwest; the remaining features appear to trace another spiral jet (jet 2) with a different orientation. The two jets form a 'double-helix' pattern which lies across {approx}200 mas. The maser distribution is reasonably fit by a model consisting of two bipolar precessing jets. The three-dimensional velocities of jet 1 and jet 2 are derived to be 138 km s{sup -1} and 99 km s{sup -1}, respectively. The precession period of jet 1 is about 56 years. For jet 2, three possible models are tested and they give different values for the kinematic parameters. We propose that the appearance of two jets is the result of a single driving source with significant proper motion.

  19. Advanced slow-magic angle spinning probe for magnetic resonance imaging and spectroscopy

    DOE Patents [OSTI]

    Wind, Robert A.; Hu, Jian Zhi; Minard, Kevin R.; Rommereim, Donald N.

    2006-01-24

    The present invention relates to a probe and processes useful for magnetic resonance imaging and spectroscopy instruments. More particularly, the invention relates to a MR probe and processes for obtaining resolution enhancements of fluid objects, including live specimens, using an ultra-slow (magic angle) spinning (MAS) of the specimen combined with a modified phase-corrected magic angle turning (PHORMAT) pulse sequence. Proton NMR spectra were measured of the torso and the top part of the belly of a female BALBc mouse in a 2T field, while spinning the animal at a speed of 1.5 Hz. Results show that even in this relatively low field with PHORMAT, an isotropic spectrum is obtained with line widths that are a factor 4.6 smaller than those obtained in a stationary mouse. Resolution of 1H NMR metabolite spectra are thus significantly enhanced. Results indicate that PHORMAT has the potential to significantly increase the utility of 1H NMR spectroscopy for in vivo biochemical, biomedical and/or medical applications involving large-sized biological objects such as mice, rats and even humans within a hospital setting. For small-sized objects, including biological objects, such as excised tissues, organs, live bacterial cells, and biofilms, use of PASS at a spinning rate of 30 Hz and above is preferred.

  20. NAVY PRECISION OPTICAL INTERFEROMETER OBSERVATIONS OF THE EXOPLANET HOST {kappa} CORONAE BOREALIS AND THEIR IMPLICATIONS FOR THE STAR'S AND PLANET'S MASSES AND AGES

    SciTech Connect (OSTI)

    Baines, Ellyn K.; Armstrong, J. Thomas [Remote Sensing Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Van Belle, Gerard T., E-mail: ellyn.baines@nrl.navy.mil [Lowell Observatory, Flagstaff, AZ 86001 (United States)

    2013-07-01

    We used the Navy Precision Optical Interferometer to measure the limb-darkened angular diameter of the exoplanet host star {kappa} CrB and obtained a value of 1.543 {+-} 0.009 mas. We calculated its physical radius (5.06 {+-} 0.04 R{sub Sun }) and used photometric measurements from the literature with our diameter to determine {kappa} CrB's effective temperature (4788 {+-} 17 K) and luminosity (12.13 {+-} 0.09 L{sub Sun }). We then placed the star on an Hertzsprung-Russell diagram to ascertain the star's age (3.42{sup +0.32}{sub -0.25} Gyr) and mass (1.47 {+-} 0.04 M{sub Sun }) using a metallicity of [Fe/H] = +0.15. With this mass, we calculated the system's mass function with the orbital elements from a variety of sources, which produced a range of planetary masses: m{sub p}sin i = 1.61-1.88 M{sub Jup}. We also updated the extent of the habitable zone for the system using our new temperature.

  1. The Stellar Imager (SI) Vision Mission

    E-Print Network [OSTI]

    Kenneth G. Carpenter; Carolus J. Schrijver; Margarita Karovska; SI Vision Mission Team

    2006-06-16

    The Stellar Imager (SI) is a UV-Optical, Space-Based Interferometer designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and of the Universe in general and asteroseismic imaging of stellar interiors. SI is identified as a "Flagship and Landmark Discovery Mission" in the 2005 Sun Solar System Connection (SSSC) Roadmap and as a candidate for a "Pathways to Life Observatory" in the Exploration of the Universe Division (EUD) Roadmap (May, 2005). SI will revolutionize our view of many dynamic astrophysical processes: its resolution will transform point sources into extended sources, and snapshots into evolving views. SI's science focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. SI's prime goal is to enable long-term forecasting of solar activity and the space weather that it drives. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. The results of the SI "Vision Mission" Study are presented in this paper. Additional information on the SI mission concept and related technology development can be found at URL: http://hires.gsfc.nasa.gov/si/.

  2. The influence of chemisorbed molecules on mass transfer in H-ZSM-5-type zeolites and the location of Broensted acid sites

    SciTech Connect (OSTI)

    Caro, J.; Buelow, M. ); Kaerger, J.; Pfeifer, H. )

    1988-11-01

    Heterogeneous catalysis is one of the most important applications of zeolites. Therefore, various methods have been developed to determine the strength and concentration of Bronsted acid sites in zeolites. Among them, in the last few years, {sup 1}H MAS NMR has become a powerful tool. In addition to the accessibility of the acid sites probed by chemisorption of N-bases, the steric environment of these catalytically active sites is of importance since it imposes constraints on the geometry of the transition state. However, only a few studies have been reported on this topic. Information was obtained from quantum chemical calculations, catalytic experiments, I.R. spectroscopy, and the arrangement of guest molecules. From these investigations it has been concluded that in H-ZSM-5 the channel intersections should be preferential location centers for the Bronsted acid sites. In adsorption technology, in the use of zeolites as shape-selective adsorbents, modification of the molecular sieve properties by chemisorption of nitrogen-containing bases (N-compounds) has become a common technique. The authors have applied the NMR pulsed field gradient technique to study the influence of chemisorbed N-compounds on transport properties of molecular sieves, considering the chemisorbed compounds as transport obstacles.

  3. Structural characterization and AC conductivity of bis tetrapropylammonium hexachlorado-dicadmate, [N(C{sub 3}H{sub 7}){sub 4}]{sub 2}Cd{sub 2}Cl{sub 6}

    SciTech Connect (OSTI)

    Hannachi, N.; Guidara, K.; Bulou, A.; Hlel, F.

    2010-11-15

    Synthesis, crystal structure, vibrational study, {sup 13}C, {sup 111}Cd CP-MAS-NMR analysis and electrical properties of the compound [N(C{sub 3}H{sub 7}){sub 4}]{sub 2}Cd{sub 2}Cl{sub 6}, are reported. The latter crystallizes in the triclinic system (space group P1-bar, Z = 2) with the following unit cell dimensions: a = 9.530(1) A, b = 11.744(1) A, c = 17.433(1) A, {alpha} = 79.31(1){sup o}, {beta} = 84.00(1){sup o} and {gamma} = 80.32(1){sup o}. Besides, its structure was solved using 6445 independent reflections down to R = 0.037. The atomic arrangement can be described by alternating organic and inorganic layers parallel to the (11-bar 0) plan, made up of tetrapropylammonium groups and Cd{sub 2}Cl{sub 6} dimers, respectively. In crystal structure, the inorganic layer, built up by Cd{sub 2}Cl{sub 6} dimers, is connected to the organic ones through van der Waals interaction in order to build cation-anion-cation cohesion. Impedance spectroscopy study, reported in the sample, reveals that the conduction in the material is due to a hopping process. The temperature and frequency dependence of dielectric constants of the single crystal sample has been investigated to determine some related parameters to the dielectric relaxation.

  4. Continuing EVN monitoring of HST-1 in the jet of M87

    E-Print Network [OSTI]

    Hada, Kazuhiro; Giovannini, Gabriele; Casadio, Carolina; Beilicke, Matthias; Cesarini, Andrea; Cheung, Teddy; Doi, Akihiro; Gómez, José Luis; Krawczynski, Henric; Kino, Motoki; Nagai, Hiroshi

    2015-01-01

    The relativistic jet in M87 offers a unique opportunity for understanding the detailed jet structure and emission processes due to its proximity. In particular, the peculiar jet region HST-1 at ~1 arcsecond (or 80 pc, projected) from the nucleus has attracted a great deal of interest in the last decade because of its superluminal motion and broadband radio-to-X-ray outbursts, which may be further connected to the gamma-ray productions up to TeV energies. Over the last five years, we have been doing an intensive monitoring of HST-1 with EVN at 5GHz in order to examine the detailed structural evolution and its possible connection to high-energy activities. While this program already yielded interesting results in terms of the detailed mas-scale structure, proper motion measurements and structural variations, the recent HST-1 brightness is continuously decreasing at this frequency. To counter this, we have shifted our monitoring frequency to 1.7GHz from October 2013. This strategy successfully recovered the fain...

  5. PSR B0329+54: Substructure in the scatter-broadened image discovered with RadioAstron on baselines of up to 235,000 km

    E-Print Network [OSTI]

    Popov, M V; Bartel, N; Gwinn, C R; Johnson, M D; Joshi, B C; Kardashev, N S; Karuppusamy, R; Kovalev, Y Y; Kramer, M; Rudnitskii, A G; Safutdinov, E R; Shishov, V I; Smirnova, T V; Soglasnov, V A; Zensus, J A; Zhuravlev, V I

    2015-01-01

    We studied scattering properties of the pulsar PSR B0329+54 with a ground-space radio interferometer RadioAstron which included the 10-m Space Radio Telescope, the 110-m Green Bank Telescope, the 14x25-m Westerbork Synthesis Radio Telescope, and the 64-m Kalyazin Radio Telescope. The observations were performed at 324 MHz on baselines of up to 235,000 km in November 2012 and January 2014. At short ground-space baselines of less than about 20,000 km, the visibility amplitude decreases with the projected baseline length, providing a direct measurement of the diameter of the scattering disk of 4.7$\\pm$0.9 mas. The size of the diffraction spot near Earth is 15,000$\\pm$3,000 km. At longer baselines of up to 235,000 km, where no interferometric detection of the scattering disk would be expected, significant visibilities were observed with amplitudes scattered around a constant value. These detections result in a discovery of a substructure in the completely resolved scatter-broadened image of the pointlike source, ...

  6. Radio monitoring of the hard state jets in the 2011 outburst of MAXI J1836-194

    E-Print Network [OSTI]

    Russell, T D; Curran, P A; Soria, R; Altamirano, D; Corbel, S; Coriat, M; Moin, A; Russell, D M; Sivakoff, G R; Slaven-Blair, T J; Belloni, T M; Fender, R P; Heinz, S; Jonker, P G; Krimm, H A; Kording, E G; Maitra, D; Markoff, S; Middleton, M; Migliari, S; Remillard, R A; Rupen, M P; Sarazin, C L; Tetarenko, A J; Torres, M A P; Tudose, V; Tzioumis, A K

    2015-01-01

    MAXI J1836-194 is a Galactic black hole candidate X-ray binary that was discovered in 2011 when it went into outburst. In this paper, we present the full radio monitoring of this system during its `failed' outburst, in which the source did not complete a full set of state changes, only transitioning as far as the hard intermediate state. Observations with the Karl G. Jansky Very Large Array (VLA) and Australia Telescope Compact Array (ATCA) show that the jet properties changed significantly during the outburst. The VLA observations detected linearly polarised emission at a level of ~1% early in the outburst, increasing to ~3% as the outburst peaked. High-resolution images with the Very Long Baseline Array (VLBA) show a ~15 mas jet along the position angle $-21 \\pm 2^\\circ$, in agreement with the electric vector position angle found from our polarisation results ($-21 \\pm 4^\\circ$), implying that the magnetic field is perpendicular to the jet. Astrometric observations suggest that the system required an asymme...

  7. Fluorine-Containing ABC Linear Triblock Terpolymers: Synthesis and Self-assembly in Solution

    SciTech Connect (OSTI)

    He, Lihong [ORNL; Hinestrosa Salazar, Juan P [ORNL; Pickel, Joseph M [ORNL; Kilbey, II, S Michael [ORNL; Mays, Jimmy [ORNL; Zhang, Shanju [Georgia Institute of Technology; Bucknall, David G. [Georgia Institute of Technology; Hong, Kunlun [ORNL

    2011-01-01

    In this paper a fluorine-containing monomer, 2-fluroroethyl methacrylate (2FEMA) was used to synthesize the linear triblock terpolymer poly(n-butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate) (PnBMA-PMMA-P2FEMA). A kinetic study of the homopolymerization of 2FEMA by reversible addition-fragmentation chain transfer (RAFT) polymerization showed that it demonstrates living character and produces well defined polymers with reasonably narrow polydispersities (~1.30). Triblock terpolymers were prepared sequentially using a purified Macro-CTA at 70 oC, resulting in final terpolymers with high Dp for each block (>150) and with polydispersities between 1.6 and 2.1. The structure and molecular weights of the resultant PnBMA-PMMA-P2FEMA triblock terpolymers were characterized via 1H NMR, 19F NMR, and gel permeation chromatography (GPC). Self-assembly of these polymers was carried out in a selective solvent and the micellar aggregates (MAs) thereby formed were analyzed using scanning electron microscopy (SEM) and dynamic light scattering (DLS). It was confirmed from SEM that these copolymers could directly self-organize into large compound micelles in tetrahydrofuran/methanol with different diameters, depending on polymer composition.

  8. Ellipsoidal primary of the RS CVn binary zeta And: Investigation using high-resolution spectroscopy and optical interferometry

    E-Print Network [OSTI]

    Korhonen, H; Kovari, Zs; Granzer, Th; Hackman, T; Strassmeier, K G

    2010-01-01

    We have obtained high-resolution spectroscopy, optical interferometry, and long-term broad band photometry of the ellipsoidal primary of the RS CVn-type binary system zeta And. Based on the optical interferometry the apparent limb darkened diameter of zeta And is 2.55 +/- 0.09 mas using a uniform disk fit. The Hipparcos distance and the limb-darkened diameter obtained with a uniform disk fit give stellar radius of 15.9 +/- 0.8 Rsolar, and combined with bolometric luminosity, it implies an effective temperature of 4665 +/- 140 K. The temperature maps obtained from high resolution spectra using Doppler imaging show a strong belt of equatorial spots and hints of a cool polar cap. The equatorial spots show a concentration around the phase 0.75. This spot configuration is reminiscent of the one seen in the earlier published temperature maps of zeta And. Investigation of the Halpha line reveals both prominences and cool clouds in the chromosphere. Long-term photometry spanning 12 years shows hints of a spot activit...

  9. Are non-magnetic mechanisms such as temporal solar diameter variations conceivable for an irradiance variability?

    E-Print Network [OSTI]

    J. P. Rozelot; S. Lefebvre; S. Pireaux; A. Ajabshirizadeh

    2006-01-05

    Irradiance variability has been monitored from space for more than two decades. Even if data are coming from different sources, it is well established that a temporal variability exists which can be set to as approximately 0.1%, in phase with the solar cycle. Today, one of the best explanation for such an irradiance variability is provided by the evolution of the solar surface magnetic fields. But if some 90 to 95% can be reproduced, what would be the origin of the 10 to 5% left? Non magnetic effects are conceivable. In this paper we will consider temporal variations of the diameter of the Sun as a possible contributor for the remaining part. Such an approach imposes strong constraints on the solar radius variability. We will show that over a solar cycle, variations of no more than 20 mas of amplitude can be considered. Such a variability (far from what is reported by observers conducting measurements by means of ground-based solar astrolabes) may explain a little part of the irradiance changes not explained by magnetic features. Further requirements are needed that may help to reach a conclusion. Dedicated space missions are necessary (for example PICARD, GOLF-NG or SDO, scheduled for a launch around 2008); it is also proposed to reactivate SDS flights for such a purpose.

  10. The Red Radio Ring: a gravitationally lensed hyperluminous infrared radio galaxy at z=2.553 discovered through citizen science

    E-Print Network [OSTI]

    Geach, J E; Verma, A; Marshall, P J; Jackson, N; Belles, P -E; Beswick, R; Baeten, E; Chavez, M; Cornen, C; Cox, B E; Erben, T; Erickson, N J; Garrington, S; Harrison, P A; Harrington, K; Hughes, D H; Ivison, R J; Jordan, C; Lin, Y -T; Leauthaud, A; Lintott, C; Lynn, S; Kapadia, A; Kneib, J -P; Macmillan, C; Makler, M; Miller, G; Montana, A; Mujica, R; Muxlow, T; Narayanan, G; Briain, D O; O'Brien, T; Oguri, M; Paget, E; Parrish, M; Ross, N P; Rozo, E; Rusu, E; Rykoff, E S; Sanchez-Arguelles, D; Simpson, R; Snyder, C; Schloerb, F P; Tecza, M; Van Waerbeke, L; Wilcox, J; Viero, M; Wilson, G W; Yun, M S; Zeballos, M

    2015-01-01

    We report the discovery of a gravitationally lensed hyperluminous infrared galaxy (L_IR~10^13 L_sun) with strong radio emission (L_1.4GHz~10^25 W/Hz) at z=2.553. The source was identified in the citizen science project SpaceWarps through the visual inspection of tens of thousands of iJKs colour composite images of Luminous Red Galaxies (LRGs), groups and clusters of galaxies and quasars. Appearing as a partial Einstein ring (r_e~3") around an LRG at z=0.2, the galaxy is extremely bright in the sub-millimetre for a cosmological source, with the thermal dust emission approaching 1 Jy at peak. The redshift of the lensed galaxy is determined through the detection of the CO(3-2) molecular emission line with the Large Millimetre Telescope's Redshift Search Receiver and through [OIII] and H-alpha line detections in the near-infrared from Subaru/IRCS. We have resolved the radio emission with high resolution (300-400 mas) eMERLIN L-band and JVLA C-band imaging. These observations are used in combination with the near-...

  11. A Galactic Center Origin for HE 0437-5439, the Hypervelocity Star near the Large Magellanic Cloud

    E-Print Network [OSTI]

    Brown, Warren R; Gnedin, Oleg Y; Bond, Howard E; Geller, Margaret J; Kenyon, Scott J; Livio, Mario; 10.1088/2041-8205/719/1/L23

    2010-01-01

    We use Hubble Space Telescope imaging to measure the absolute proper motion of the hypervelocity star (HVS) HE 0437-5439, a short-lived B star located in the direction of the Large Magellanic Cloud (LMC). We observe (\\mu_\\alpha, \\mu_\\delta)=(+0.53+-0.25(stat)+-0.33(sys), +0.09+-0.21(stat)+-0.48(sys)) mas/yr. The velocity vector points directly away from the center of the Milky Way; an origin from the center of the LMC is ruled out at the 3-sigma level. The flight time of the HVS from the Milky Way exceeds its main-sequence lifetime, thus its stellar nature requires it to be a blue straggler. The large space velocity rules out a Galactic-disk ejection. Combining the HVS's observed trajectory, stellar nature, and required initial velocity, we conclude that HE 0437-5439 was most likely a compact binary ejected by the Milky Way's central black hole.

  12. Modeling of Interstellar Scintillation Arcs from Pulsar B1133+16

    E-Print Network [OSTI]

    Frank S. Trang; Barney J. Rickett

    2007-02-07

    The parabolic arc phenomenon visible in the Fourier analysis of the scintillation spectra of pulsars provides a new method of investigating the small scale structure in the ionized interstellar medium (ISM). We report archival observations of the pulsar B1133+16 showing both forward and reverse parabolic arcs sampled over 14 months. These features can be understood as the mutual interference between an assembly of discrete features in the scattered brightness distribution. By model-fitting to the observed arcs at one epoch we obtain a ``snap-shot'' estimate of the scattered brightness, which we show to be highly anisotropic (axial ratio >10:1), to be centered significantly off axis and to have a small number of discrete maxima, which are coarser the speckle expected from a Kolmogorov spectrum of interstellar plasma density. The results suggest the effects of highly localized discrete scattering regions which subtend 0.1-1 mas, but can scatter (or refract) the radiation by angles that are five or more times larger.

  13. Nature of high-energy ions in the cathode plasma jet of a vacuum arc with high rate of current rise

    SciTech Connect (OSTI)

    Beilis, I.I.

    2004-10-04

    The production mechanism of extremely high-energy (up to 10 keV) ions observed in vacuum arcs having only a few tens of volts of arc voltage was considered. A model was developed for the plasma acceleration in a high-current ({>=}1 kA) short pulsed (<1 {mu}s) vacuum arc, taking into account the high rate of rise of the spot current (dI/dt>100 MA/s). A system of equations, including equations for the cathode spot and the plasma jet, was solved self-consistently with dI/dt in the range of 0.1-10 GA/s. It was shown that the plasma could be accelerated to the measured energy in the near spot region due to a gas dynamic mechanism and that the ion energy depends on the ratio of the ion flux to the electron flux. This ratio is determined by the cathode erosion rate. The calculated cathode erosion rate varies from 200 to 10 {mu}g/C when the ion energy increases from 0.1 to 10 keV and well agrees with measurements.

  14. Hubble Tarantula Treasury Project. III. Photometric Catalog and Resulting Constraints on the Progression of Star Formation in the 30 Doradus Region

    E-Print Network [OSTI]

    Sabbi, E; Anderson, J; Cignoni, M; van der Marel, R P; Zaritsky, D; de Marchi, G; Panagia, N; Gouliermis, D A; Grebel, E K; Gallager, J S; Smith, L J; Sana, H; Aloisi, A; Tosi, M; Evans, C J; Arab, H; Boyer, M; de Mink, S E; Gordon, K; Koekemoer, A M; Larsen, S S; Ryon, J E; Zeidler, P

    2015-01-01

    We present and describe the astro-photometric catalog of more than 800,000 sources found in the Hubble Tarantula Treasury Project (HTTP). HTTP is a Hubble Space Telescope (HST) Treasury program designed to image the entire 30 Doradus region down to the sub-solar (~0.5 solar masses) mass regime using the Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS). We observed 30 Doradus in the near ultraviolet (F275W, F336W), optical (F555W, F658N, F775W), and near infrared (F110W, F160W) wavelengths. The stellar photometry was measured using point-spread function (PSF) fitting across all the bands simultaneously. The relative astrometric accuracy of the catalog is 0.4 mas. The astro-photometric catalog, results from artificial star experiments and the mosaics for all the filters are available for download. Color-magnitude diagrams are presented showing the spatial distributions and ages of stars within 30 Dor as well as in the surrounding fields. HTTP provides the first rich and statistically signifi...

  15. Advance Resource Provisioning in Bulk Data Scheduling

    SciTech Connect (OSTI)

    Balman, Mehmet

    2012-10-01

    Today?s scientific and business applications generate mas- sive data sets that need to be transferred to remote sites for sharing, processing, and long term storage. Because of increasing data volumes and enhancement in current net- work technology that provide on-demand high-speed data access between collaborating institutions, data handling and scheduling problems have reached a new scale. In this paper, we present a new data scheduling model with ad- vance resource provisioning, in which data movement operations are defined with earliest start and latest comple- tion times. We analyze time-dependent resource assign- ment problem, and propose a new methodology to improve the current systems by allowing researchers and higher-level meta-schedulers to use data-placement as-a-service, so they can plan ahead and submit transfer requests in advance. In general, scheduling with time and resource conflicts is NP-hard. We introduce an efficient algorithm to organize multiple requests on the fly, while satisfying users? time and resource constraints. We successfully tested our algorithm in a simple benchmark simulator that we have developed, and demonstrated its performance with initial test results.

  16. Perm Web: remote parallel and distributed volume visualization

    SciTech Connect (OSTI)

    Wittenbrink, C.M.; Kim, K.; Story, J.; Pang, A.; Hollerbach, K.; Max, N.

    1997-01-01

    In this paper we present a system for visualizing volume data from remote supercomputers (PermWeb). We have developed both parallel volume rendering algorithms, and the World Wide Web software for accessing the data at the remote sites. The implementation uses Hypertext Markup Language (HTML), Java, and Common Gateway Interface (CGI) scripts to connect World Wide Web (WWW) servers/clients to our volume renderers. The front ends are interactive Java classes for specification of view, shading, and classification inputs. We present performance results, and implementation details for connections to our computing resources at the University of California Santa Cruz including a MasPar MP-2, SGI Reality Engine-RE2, and SGI Challenge machines. We apply the system to the task of visualizing trabecular bone from finite element simulations. Fast volume rendering on remote compute servers through a web interface allows us to increase the accessibility of the results to more users. User interface issues, overviews of parallel algorithm developments, and overall system interfaces and protocols are presented. Access is available through Uniform Resource Locator (URL) http://www.cse.ucsc.edu/research/slvg/. 26 refs., 7 figs.

  17. DISTANCE AND KINEMATICS OF THE TW HYDRAE ASSOCIATION FROM PARALLAXES

    SciTech Connect (OSTI)

    Weinberger, Alycia J.; Boss, Alan P.; Anglada-Escude, Guillem

    2013-01-10

    From common proper motion and signatures of youth, researchers have identified about 30 members of a putative TW Hydrae Association. Only four of these had parallactic distances from Hipparcos. We have measured parallaxes and proper motions for 14 primary members. We combine these with literature values of radial velocities to show that the Galactic space motions of the stars, with the exception of TWA 9 and 22, are parallel and do not indicate convergence at a common formation point sometime in the last few million years. The space motions of TWA 9 and 22 do not agree with the others and indicate that they are not TWA members. The median parallax is 18 mas or 56 pc. We further analyze the stars' absolute magnitudes on pre-main-sequence evolutionary tracks and find a range of ages with a median of 10.1 Myr and no correlation between age and Galactic location. The TWA stars may have formed from an extended and filamentary molecular cloud but are not necessarily precisely coeval.

  18. The nature of the methanol maser ring G23.657-00.127

    E-Print Network [OSTI]

    A. Bartkiewicz; A. Brunthaler; M. Szymczak; H. J. van Langevelde; M. J. Reid

    2008-09-11

    Methanol masers are associated with young high-mass stars and are an important tool for investigating the process of massive star formation. The recently discovered methanol maser ring in G23.657-00.127 provides an excellent ``laboratory'' for a detailed study of the nature and physical origin of methanol maser emission, as well as parallax and proper motion measurements. Multi-epoch observations of the 12.2 GHz methanol maser line from the ring were conducted using the Very Long Baseline Array. Interferometric observations with milliarcsecond resolution enabled us to track single maser spots in great detail over a period of 2 years. We have determined the trigonometric parallax of G23.657-00.127 to be 0.313+/-0.039 mas, giving a distance of 3.19{+0.46}{-0.35} kpc. The proper motion of the source indicates that it is moving with the same circular velocity as the LSR, but it shows a large peculiar motion of about 35 km/s toward the Galactic center.

  19. TESTING THE HYPOTHESIS THAT METHANOL MASER RINGS TRACE CIRCUMSTELLAR DISKS: HIGH-RESOLUTION NEAR-INFRARED AND MID-INFRARED IMAGING

    SciTech Connect (OSTI)

    De Buizer, James M. [Stratospheric Observatory for Infrared Astronomy-USRA, NASA Ames Research Center, MS N232-12, Moffett Field, CA 94035 (United States); Bartkiewicz, Anna; Szymczak, Marian, E-mail: jdebuizer@sofia.usra.edu [Torun Centre for Astronomy, Nicolaus Copernicus University, Gagarina 11, 87-100 Torun (Poland)

    2012-08-01

    Milliarcsecond very long baseline interferometry maps of regions containing 6.7 GHz methanol maser emission have lead to the recent discovery of ring-like distributions of maser spots and the plausible hypothesis that they may be tracing circumstellar disks around forming high-mass stars. We aimed to test this hypothesis by imaging these regions in the near- and mid-infrared at high spatial resolution and compare the observed emission to the expected infrared morphologies as inferred from the geometries of the maser rings. In the near-infrared we used the Gemini North adaptive optics system of ALTAIR/NIRI, while in the mid-infrared we used the combination of the Gemini South instrument T-ReCS and super-resolution techniques. Resultant images had a resolution of {approx}150 mas in both the near-infrared and mid-infrared. We discuss the expected distribution of circumstellar material around young and massive accreting (proto)stars and what infrared emission geometries would be expected for the different maser ring orientations under the assumption that the masers are coming from within circumstellar disks. Based upon the observed infrared emission geometries for the four targets in our sample and the results of spectral energy distribution modeling of the massive young stellar objects associated with the maser rings, we do not find compelling evidence in support of the hypothesis that methanol masers rings reside in circumstellar disks.

  20. Structure of rhenium-containing sodium borosilicate glass

    SciTech Connect (OSTI)

    Goel, Ashutosh; McCloy, John S.; Windisch, Charles F.; Riley, Brian J.; Schweiger, Michael J.; Rodriguez, Carmen P.; Ferreira, Jose M.

    2013-03-01

    A series of sodium borosilicate glasses were synthesized with increasing fractions of KReO4 or Re2O7, to 10000 ppm (1 mass%) target Re in glass, to assess the effects of large concentrations of rhenium on glass structure and to estimate the solubility of technetium, a radioactive component in typical low active waste nuclear waste glasses. Magic angle spinning nuclear magnetic resonance (MAS-NMR), Fourier transform infrared (FTIR) spectroscopy, and Raman spectroscopy were performed to characterize the glasses as a function of Re source additions. In general, silicon was found coordinated in a mixture of Q2 and Q3 structural units, while Al was 4-coordinated and B was largely 3-coordinate and partially 4-coordinated. The rhenium source did not appear to have significant effects on the glass structure. Thus, at the up to the concentrations that remain in dissolved in glass, ~3000 ppm Re by mass maximum. , the Re appeared to be neither a glass-former nor a strong glass modifier., Rhenium likely exists in isolated ReO4- anions in the interstices of the glass network, as evidenced by the polarized Raman spectrum of the Re glass in the absence of sulfate. Analogous to SO42-¬ in similar glasses, ReO4- is likely a network modifier and forms alkali salt phases on the surface and in the bulk glass above solubility.

  1. Physical properties of the gamma-ray binary LS 5039 through low and high frequency radio observations

    E-Print Network [OSTI]

    Marcote, B; Paredes, J M; Ishwara-Chandra, C H

    2015-01-01

    We have studied in detail the 0.15-15 GHz radio spectrum of the gamma-ray binary LS 5039 to look for a possible turnover and absorption mechanisms at low frequencies, and to constrain the physical properties of its emission. We have analysed two archival VLA monitorings, all the available archival GMRT data and a coordinated quasi-simultaneous observational campaign conducted in 2013 with GMRT and WSRT. The data show that the radio emission of LS 5039 is persistent on day, week and year timescales, with a variability $\\lesssim 25~\\%$ at all frequencies, and no signature of orbital modulation. The obtained spectra reveal a power-law shape with a curvature below 5 GHz and a turnover at $\\sim0.5$ GHz, which can be reproduced by a one-zone model with synchrotron self-absorption plus Razin effect. We obtain a coherent picture for a size of the emitting region of $\\sim0.85~\\mathrm{mas}$, setting a magnetic field of $B\\sim20~\\mathrm{mG}$, an electron density of $n_{\\rm e}\\sim4\\times10^5~{\\rm cm^{-3}}$ and a mass-los...

  2. Alkaline solution/binder ratio as a determining factor in the alkaline activation of aluminosilicates

    SciTech Connect (OSTI)

    Ruiz-Santaquiteria, C.; Fernandez-Jimenez, A.; Palomo, A.

    2012-09-15

    This study investigates the effect of the alkaline solution/binder (S/B) ratio on the composition and nanostructure of the reaction products generated in the alkaline activation of aluminosilicates. The experiments used two mixtures of fly ash and dehydroxylated white clay and for each of these, varying proportions of the solution components. The alkali activator was an 8 M NaOH solution (with and without sodium silicate) used at three S/B ratios: 0.50, 0.75 and 1.25. The {sup 29}Si, {sup 27}Al MAS NMR and XRD characterisation of the reaction products reveal that for ratios nearest the value delivering suitable paste workability, the reaction-product composition and structure depend primarily on the nature and composition of the starting materials and the alkaline activator used. However, when an excess alkaline activator is present in the system, the reaction products tend to exhibit SiO{sub 2}/Al{sub 2}O{sub 3} ratios of approximately 1, irrespective of the composition of the starting binder or the alkaline activator.

  3. Exploring intermediate (5-40AU) scales around AB Aurigae with the Palomar Fiber Nuller

    E-Print Network [OSTI]

    Kuhn, Jonas; Liewer, Kurt; Martin, Stefan; Loya, Frank; Millan-Gabet, Rafael; Serabyn, Eugene

    2015-01-01

    We report on recent Ks-band interferometric observations of the young pre-main-sequence star AB Aurigae obtained with the Palomar Fiber Nuller (PFN). Reaching a contrast of a few 10-4 inside a field of view extending from 35 to 275 mas (5-40AU at AB Aur's distance), the PFN is able to explore angular scales that are intermediate between those accessed by coronagraphic imaging and long baseline interferometry. This intermediate region is of special interest given that many young stellar objects are believed to harbor extended halos at such angular scales. Using destructive interference (nulling) between two sub-apertures of the Palomar 200 inch telescope and rotating the telescope pupil, we measured a resolved circumstellar excess at all probed azimuth angles. The astrophysical null measured over the full rotation is fairly constant, with a mean value of 1.52%, and a slight additional azimuthal modulation of +/-0.2%. The isotropic astrophysical null is indicative of circumstellar emission dominated by an azimu...

  4. A New Merging Double Degenerate Binary in the Solar Neighborhood

    E-Print Network [OSTI]

    Debes, John H; Tremblay, Pier-Emmanuel; López-Morales, Mercedes; Anglada-Escudé, Guillem; Napiwotzki, Ralf; Osip, David; Weinberger, Alycia

    2015-01-01

    Characterizing the local space density of double degenerate binary systems is a complementary approach to broad sky surveys of double degenerates to determine the expected rates of white dwarf binary mergers, in particular those that may evolve into other observable phenomena such as extreme helium stars, Am CVn systems, and supernovae Ia. However, there have been few such systems detected in local space. We report here the discovery that WD 1242$-$105, a nearby bright WD, is a double-line spectroscopic binary consisting of two degenerate DA white dwarfs of similar mass and temperature, despite it previously having been spectroscopically characterized as a single degenerate. Follow-up photometry, spectroscopy, and trigonometric parallax have been obtained in an effort to determine the fundamental parameters of each component of this system. The binary has a mass ratio of 0.7 and a trigonometric parallax of 25.5 mas, placing it at a distance of 39 pc. The system's total mass is 0.95 M$_\\odot$ and has an orbita...

  5. The Binary White Dwarf LHS 3236

    E-Print Network [OSTI]

    Harris, Hugh; Dupuy, Trent; Canzian, Blaise; Guetter, Harry; Hartkopf, William; Ireland, Michael; Leggett, Sandy; Levine, Stephen; Liu, Michael; Luginbuhl, Christian; Monet, Alice; Stone, Ronald; Subasavage, John; Tilleman, Trudy; Walker, Richard

    2013-01-01

    The white dwarf LHS 3236 (WD1639+153) is shown to be a double-degenerate binary, with each component having a high mass. Astrometry at the U.S. Naval Observatory gives a parallax and distance of 30.86 +/- 0.25 pc and a tangential velocity of 98 km/s, and reveals binary orbital motion. The orbital parameters are determined from astrometry of the photocenter over more than three orbits of the 4.0-year period. High-resolution imaging at the Keck Observatory resolves the pair with a separation of 31 and 124 mas at two epochs. Optical and near-IR photometry give a set of possible binary components. Consistency of all data indicates that the binary is a pair of DA stars with temperatures near 8000 and 7400 K and with masses of 0.93 and 0.91 M_solar; also possible, is a DA primary and a helium DC secondary with temperatures near 8800 and 6000 K and with masses of 0.98 and 0.69 M_solar. In either case, the cooling ages of the stars are ~3 Gyr and the total ages are <4 Gyr. The combined mass of the binary (1.66--1....

  6. The binary white dwarf LHS 3236

    SciTech Connect (OSTI)

    Harris, Hugh C.; Dahn, Conard C.; Canzian, Blaise; Guetter, Harry H.; Levine, Stephen E.; Luginbuhl, Christian B.; Monet, Alice K. B.; Stone, Ronald C.; Subasavage, John P.; Tilleman, Trudy; Walker, Richard L. [US Naval Observatory, 10391 West Naval Observatory Road, Flagstaff, AZ 86001-8521 (United States); Dupuy, Trent J.; Liu, Michael C. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Hartkopf, William I. [US Naval Observatory, 3450 Massachusetts Avenue, N.W., Washington, DC 20392-5420 (United States); Ireland, Michael J. [Department of Physics and Astronomy, Macquarie University, New South Wales, NSW 2109 (Australia); Leggett, S. K., E-mail: hch@nofs.navy.mil [Gemini Observatory, 670 N. Aohoku Place, Hilo, HI 96720 (United States)

    2013-12-10

    The white dwarf LHS 3236 (WD1639+153) is shown to be a double-degenerate binary, with each component having a high mass. Astrometry at the U.S. Naval Observatory gives a parallax and distance of 30.86 ± 0.25 pc and a tangential velocity of 98 km s{sup –1}, and reveals binary orbital motion. The orbital parameters are determined from astrometry of the photocenter over more than three orbits of the 4.0 yr period. High-resolution imaging at the Keck Observatory resolves the pair with a separation of 31 and 124 mas at two epochs. Optical and near-IR photometry give a set of possible binary components. Consistency of all data indicates that the binary is a pair of DA stars with temperatures near 8000 and 7400 K and with masses of 0.93 and 0.91 M {sub ?}; also possible is a DA primary and a helium DC secondary with temperatures near 8800 and 6000 K and with masses of 0.98 and 0.69 M {sub ?}. In either case, the cooling ages of the stars are ?3 Gyr and the total ages are <4 Gyr. The combined mass of the binary (1.66-1.84 M {sub ?}) is well above the Chandrasekhar limit; however, the timescale for coalescence is long.

  7. Subsea manifolds optimization -- The combination of mature and new technologies

    SciTech Connect (OSTI)

    Paulo, C.A.S.

    1996-12-31

    Subsea equipment can now be considered a mature option for offshore field developments. In Brazil, since the first oil in Campos Basin, different concepts ranging from one-atmosphere chambers to deepwater guidelineless X-mas trees, have been tested, contributing to this development. The experience acquired during these years makes it possible to combine the proven systems with new technologies being developed, for the design of subsea manifolds. The main target is more efficiency and cost reduction. When choosing a manifold concept, a usual rule is applicable: the simpler the better. The maturity, confidence and reliability obtained, allow the usage of resident hydraulically actuated valves, simplifying considerably the manifold arrangement. Other contributions come from: the reduction of piping bend radius allowed by the new pigs; the increased reliability of subsea instrumentation and chokes, allowing elimination of the gas-lift-test flowline; and the development of the direct vertical connection, that turns subsea tie-ins into very fast and easy operations. Combining all that with the new technology of a multiphase meter (to eliminate the test flowline and even the test separator on the platform), one can achieve a cost effective solution. This paper describes the possibilities of simplifying the subsea manifolds and presents a comparison of different designs. The usage of mature technology combined with the new developments, can help the industry to make deep water developments profitable, worldwide.

  8. Monitoring lensed starlight emitted close to the Galactic Center

    E-Print Network [OSTI]

    Adi Nusser; Tom Broadhurst

    2004-07-12

    We describe the feasibility of detecting the gravitational deflection of light emitted by stars moving under the influence of the massive object at the Galactic center. Light emitted by a star orbiting behind the central mass has a smaller impact parameter than the star itself, and suffers the effect of gravitational lensing, providing a closer probe of the central mass distribution and hence a stricter test of the black hole hypothesis. A mass of $4.3\\times 10^{6} M_{\\odot}$ causes a $0.1-2\\rm mas$ deviation in the apparent position of orbiting stars projected within $10^{\\circ}$ of the line of sight to the galactic center. In addtion, we may uniquely constrain the distance to the center of the galaxy because lensing deflections constrain the ratio $\\rg/R_{0}$ of the Schwarzschild radius to the distance to the black hole, $R_{o}$, whereas the ratio $\\rg/R_{o}^{3}$ is obtained by fitting the orbit.

  9. A Brown Dwarf Microlens Candidate in the OGLE-II Database

    E-Print Network [OSTI]

    M. C. Smith; S. Mao; P. R. Wozniak

    2003-01-16

    We describe a unique mass determination for a microlensing event from the second phase of the Optical Gravitational Microlensing Experiment (OGLE-II). The event, sc26_2218, which is very bright (baseline magnitude I=15.10), appears to exhibit both parallax and finite source effects. The parallax effect allows us to determine the projected Einstein radius on the observer plane (approx. 3.8 AU), while the finite source effect allows us to determine the ratio of the angular source size and the angular Einstein radius. As the angular size of the star can be estimated using its color and magnitude, we can hence determine the angular Einstein radius (approx. 0.1 mas). By combining both the projected and angular Einstein radius we can determine the lens mass M = 0.050^{+0.016}_{-0.011} solar masses, independent of the source distance. The lens is therefore a brown dwarf candidate. However, the `parallax' signature is weak and so we cannot completely discount the possibility that these signatures originate from binary rotation of the source (which would prevent any estimate of the lens mass), rather than parallax. However, this can be tested by future spectroscopic observations. This event highlights the scientific returns for intense monitoring of bright microlensing events, since the parallax and finite source effects can be more easily identified due to their high signal-to-noise ratios.

  10. X-ray analysis of the proper motion and pulsar wind nebula for PSR J1741-2054

    E-Print Network [OSTI]

    Auchettl, Katie; Romani, Roger W; Posselt, Bettina; Pavlov, George G; Kargaltsev, Oleg; Ng, C-Y; Temim, Tea; Weisskopf, Martin C; Bykov, Andrei; Swartz, Douglas A

    2015-01-01

    We obtained six observations of PSR J1741-2054 using the $Chandra$ ACIS-S detector totaling $\\sim$300 ks. By registering this new epoch of observations to an archival observation taken 3.2 years earlier using X-ray point sources in the field of view, we have measured the pulsar proper motion at $\\mu =109 \\pm 10$ mas/yr. The spectrum of the pulsar can be described by an absorbed power law with photon index $\\Gamma$=2.68$\\pm$0.04, plus a blackbody with an emission radius of (4.5$^{+3.2}_{-2.5})d_{0.38}$ km, for a DM-estimated distance of $0.38d_{0.38}$ kpc and a temperature of $61.7\\pm3.0$ eV. Emission from the compact nebula is well described by an absorbed power law model with a photon index of $\\Gamma$ = 1.67$\\pm$0.06, while the diffuse emission seen as a trail extending northeast of the pulsar shows no evidence of synchrotron cooling. We also looked for extended features that might represent a jet or torus-like structure using image deconvolution and PSF-subtraction but we find no conclusive evidence of suc...

  11. Opacity in compact extragalactic radio sources and its effect on radio-optical reference frame alignment

    E-Print Network [OSTI]

    Y. Y. Kovalev; A. P. Lobanov; A. B. Pushkarev; J. A. Zensus

    2007-10-22

    Accurate alignment of the radio and optical celestial reference frames requires detailed understanding of physical factors that may cause offsets between the positions of the same object measured in different spectral bands. Opacity in compact extragalactic jets (due to synchrotron self-absorption and external free-free absorption) is one of the key physical phenomena producing such an offset, and this effect is well-known in radio astronomy ("core shift"). We have measured the core shifts in a sample of 29 bright compact extragalactic radio sources observed using very long baseline interferometry (VLBI) at 2.3 and 8.6 GHz. We report the results of these measurements and estimate that the average shift between radio and optical positions of distant quasars would be of the order of 0.1-0.2 mas. This shift exceeds positional accuracy of GAIA and SIM. We suggest two possible approaches to carefully investigate and correct for this effect in order to align accurately the radio and optical positions. Both approaches involve determining a Primary Reference Sample of objects to be used for tying the radio and optical reference frames together.

  12. Intramolecular condensation reactions of {alpha},{omega}-bis(triethoxysilyl)alkanes. Formation of cyclic disilsesquioxanes

    SciTech Connect (OSTI)

    Loy, D.A.; Carpenter, J.P.; Myers, S.A.; Assink, R.A. [Sandia National Lab., Albuquerque, NM (United States)] [Sandia National Lab., Albuquerque, NM (United States); Small, J.H.; Greaves, J.; Shea, K.J. [Univ. of California, Irvine, CA (United States)] [Univ. of California, Irvine, CA (United States)

    1996-09-04

    In this paper, we used mass spectrometry and {sup 29}Si NMR spectroscopy to discover that the length of the alkylene-bridging groups had a pronounced effect on the competition between cyclization and polymerization of {alpha},{omega}-bis(triethoxysilyl)alkanes and on the formation of polymeric gels. While the intramolecular reaction clearly slows gelation, the cyclic disilsesquioxanes are still tetrafunctional monomers theoretically capable of forming polymeric gels. If the ring structures, which bear a striking resemblence to carbohydrates, are preserved through the polymerization, the resulting poly(cyclic disilsesquioxane) gels may have structural similarities to branched or cross-linked carbohydrates, such as cellulose or chitosan. Under base-catalyzed sol-gel polymerization conditions, 3 and 4 (six- and seven-membered cyclic disilsesquioxanes, respectively) quickly reacted to give gels with significant ring opening as determined from the {sup 29}Si chemical shifts in solid-state (CP MAS) NMR spectra. However, gels prepared under acidic conditions reveal some or all of the cyclic disilsesquioxane functionality was preserved in the polymers. 13 refs., 1 fig.

  13. Chemical structure and properties of low-rank coals treated by hydrothermal process

    SciTech Connect (OSTI)

    Ohki, A.; Xie, X.F.; Nakajima, Tsunenori; Maeda, Shigeru [Kagoshima Univ., Korimoto, Kagoshima (Japan). Dept. of Applied Chemistry and Chemical Engineering

    1998-12-31

    Several methods for upgrading low-rank coals, in which the hygroscopicity is irreversibly reduced into a level for high-rank coals, have been developed. A hydrothermal treatment of coal, such as hot water drying (HWD), is one of the most promising upgrading methods. The HWD method involves a treatment of low-rank coals under high temperature (300-350 C) and high pressure (80-180 kg/cm{sup 2}). Two low-rank coals, Loy Yang coal and Yallourn coal were hydrothermally treated at 150--350 C. The chemical structure and properties of these treated coals have been examined. The analysis of coal includes hygroscopicity, elemental analysis, the content of oxygenic functional groups measured by chemical analysis, FTIR analysis, CP/MAS {sup 13}C NMR analysis, specific surface area, maceral composition, and vitrinite reflectance. When the low-rank coals are hydrothermally treated, the hygroscopicity of coal remarkably decreases. The content of carboxyl group in coal greatly decreases as heat treatment temperature (HTT) is raised. The difference in carboxyl group content in the 350 C-treated coal between from the chemical analysis and from {sup 13}C NMR and FTIR analyses is explained. From these results, the change in chemical structure and properties of coal during the hydrothermal treatment is discussed.

  14. Astrometric orbits of SB9 stars

    E-Print Network [OSTI]

    Jancart, S; Babusiaux, C; Pourbaix, D

    2005-01-01

    Hipparcos Intermediate Astrometric Data (IAD) have been used to derive astrometric orbital elements for spectroscopic binaries from the newly released Ninth Catalogue of Spectroscopic Binary Orbits (SB9). Among the 1374 binaries from SB9 which have an HIP entry, 282 have detectable orbital astrometric motion (at the 5% significance level). Among those, only 70 have astrometric orbital elements that are reliably determined (according to specific statistical tests discussed in the paper), and for the first time for 20 systems, representing a 10% increase relative to the 235 DMSA/O systems already present in the Hipparcos Double and Multiple Systems Annex. The detection of the astrometric orbital motion when the Hipparcos IAD are supplemented by the spectroscopic orbital elements is close to 100% for binaries with only one visible component, provided that the period is in the 50 - 1000 d range and the parallax is larger than 5 mas. This result is an interesting testbed to guide the choice of algorithms and stati...

  15. New hypodiphosphates of the alkali metals: Synthesis, crystal structure and vibrational spectra of the hypodiphosphates(IV) M{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (M=Rb and Cs)

    SciTech Connect (OSTI)

    Wu, Peng [Institut fuer Anorganische und Analytische Chemie der TU Clausthal, Paul-Ernst-Strasse 4, D-38678 Clausthal-Zellerfeld (Germany)] [Institut fuer Anorganische und Analytische Chemie der TU Clausthal, Paul-Ernst-Strasse 4, D-38678 Clausthal-Zellerfeld (Germany); Wiegand, Thomas; Eckert, Hellmut [Institut fuer Physikalische Chemie and Graduate School of Chemistry, Westfaelische Wilhelms-Universitaet Muenster, Corrensstr. 28/30, D-48149 Muenster (Germany)] [Institut fuer Physikalische Chemie and Graduate School of Chemistry, Westfaelische Wilhelms-Universitaet Muenster, Corrensstr. 28/30, D-48149 Muenster (Germany); Gjikaj, Mimoza, E-mail: mimoza.gjikaj@tu-clausthal.de [Institut fuer Anorganische und Analytische Chemie der TU Clausthal, Paul-Ernst-Strasse 4, D-38678 Clausthal-Zellerfeld (Germany)] [Institut fuer Anorganische und Analytische Chemie der TU Clausthal, Paul-Ernst-Strasse 4, D-38678 Clausthal-Zellerfeld (Germany)

    2012-10-15

    The new hypodiphosphates(IV) Rb{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (1) and Cs{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (2) were synthesized by soft chemistry reactions from aqueous solutions of hypophosphoric acid and the corresponding heavy alkali-metal carbonates. Their crystal structures were determined by single crystal X-ray diffraction. Both compounds crystallize isotypic in the triclinic space group P-1 with one formula unit in the unit cell. The structures are built up by discrete (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) units in staggered conformation for the P{sub 2}O{sub 6} skeleton and the corresponding alkali-metal cations. In the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} ion the hydrogen atoms are in a 'trans-trans' conformation. O{center_dot}H-O hydrogen bonds between the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) groups consolidate the structures into a three-dimensional network. The FT-Raman and {sup 31}P and {sup 1}H and MAS NMR spectra of the title compounds have been recorded and interpreted, especially with respect to their assignment to the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) groups. Thermogravimetric data of 2 have been interpreted in terms of a thermal decomposition model. - Graphical Abstract: The layered compounds Rb{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] and Cs{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] have been synthesized and investigated. Both crystallize isotypic. The structures are built up by discrete (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) units and the corresponding alkali-metal cations. Highlights: Black-Right-Pointing-Pointer Synthesis and single-crystal structure of new alkali hypodiphosphates. Black-Right-Pointing-Pointer Structures are characterized by [(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})]{sup 2-} units and M{sup +} cations. Black-Right-Pointing-Pointer (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) units are linked by short hydrogen bonds. Black-Right-Pointing-Pointer Both compounds are characterized by {sup 31}P MAS-NMR spectra.

  16. Statistical model based iterative reconstruction (MBIR) in clinical CT systems: Experimental assessment of noise performance

    SciTech Connect (OSTI)

    Li, Ke; Tang, Jie; Chen, Guang-Hong

    2014-04-15

    Purpose: To reduce radiation dose in CT imaging, the statistical model based iterative reconstruction (MBIR) method has been introduced for clinical use. Based on the principle of MBIR and its nonlinear nature, the noise performance of MBIR is expected to be different from that of the well-understood filtered backprojection (FBP) reconstruction method. The purpose of this work is to experimentally assess the unique noise characteristics of MBIR using a state-of-the-art clinical CT system. Methods: Three physical phantoms, including a water cylinder and two pediatric head phantoms, were scanned in axial scanning mode using a 64-slice CT scanner (Discovery CT750 HD, GE Healthcare, Waukesha, WI) at seven different mAs levels (5, 12.5, 25, 50, 100, 200, 300). At each mAs level, each phantom was repeatedly scanned 50 times to generate an image ensemble for noise analysis. Both the FBP method with a standard kernel and the MBIR method (Veo{sup ®}, GE Healthcare, Waukesha, WI) were used for CT image reconstruction. Three-dimensional (3D) noise power spectrum (NPS), two-dimensional (2D) NPS, and zero-dimensional NPS (noise variance) were assessed both globally and locally. Noise magnitude, noise spatial correlation, noise spatial uniformity and their dose dependence were examined for the two reconstruction methods. Results: (1) At each dose level and at each frequency, the magnitude of the NPS of MBIR was smaller than that of FBP. (2) While the shape of the NPS of FBP was dose-independent, the shape of the NPS of MBIR was strongly dose-dependent; lower dose lead to a “redder” NPS with a lower mean frequency value. (3) The noise standard deviation (?) of MBIR and dose were found to be related through a power law of ????(dose){sup ??} with the component ? ? 0.25, which violated the classical ????(dose){sup ?0.5} power law in FBP. (4) With MBIR, noise reduction was most prominent for thin image slices. (5) MBIR lead to better noise spatial uniformity when compared with FBP. (6) A composite image generated from two MBIR images acquired at two different dose levels (D1 and D2) demonstrated lower noise than that of an image acquired at a dose level of D1+D2. Conclusions: The noise characteristics of the MBIR method are significantly different from those of the FBP method. The well known tradeoff relationship between CT image noise and radiation dose has been modified by MBIR to establish a more gradual dependence of noise on dose. Additionally, some other CT noise properties that had been well understood based on the linear system theory have also been altered by MBIR. Clinical CT scan protocols that had been optimized based on the classical CT noise properties need to be carefully re-evaluated for systems equipped with MBIR in order to maximize the method's potential clinical benefits in dose reduction and/or in CT image quality improvement.

  17. MOJAVE. X. PARSEC-SCALE JET ORIENTATION VARIATIONS AND SUPERLUMINAL MOTION IN ACTIVE GALACTIC NUCLEI

    SciTech Connect (OSTI)

    Lister, M. L.; Richards, J. L.; Aller, M. F.; Aller, H. D.; Homan, D. C.; Kellermann, K. I.; Kovalev, Y. Y.

    2013-11-01

    We describe the parsec-scale kinematics of 200 active galactic nucleus (AGN) jets based on 15 GHz Very Long Baseline Array (VLBA) data obtained between 1994 August 31 and 2011 May 1. We present new VLBA 15 GHz images of these and 59 additional AGNs from the MOJAVE and 2 cm Survey programs. Nearly all of the 60 most heavily observed jets show significant changes in their innermost position angle over a 12-16 yr interval, ranging from 10° to 150° on the sky, corresponding to intrinsic variations of ?0.°5 to ?2°. The BL Lac jets show smaller variations than quasars. Roughly half of the heavily observed jets show systematic position angle trends with time, and 20 show indications of oscillatory behavior. The time spans of the data sets are too short compared to the fitted periods (5-12 yr), however, to reliably establish periodicity. The rapid changes and large jumps in position angle seen in many cases suggest that the superluminal AGN jet features occupy only a portion of the entire jet cross section and may be energized portions of thin instability structures within the jet. We have derived vector proper motions for 887 moving features in 200 jets having at least five VLBA epochs. For 557 well-sampled features, there are sufficient data to additionally study possible accelerations. We find that the moving features are generally non-ballistic, with 70% of the well-sampled features showing either significant accelerations or non-radial motions. Inward motions are rare (2% of all features), are slow (<0.1 mas yr{sup –1}), are more prevalent in BL Lac jets, and are typically found within 1 mas of the unresolved core feature. There is a general trend of increasing apparent speed with distance down the jet for both radio galaxies and BL Lac objects. In most jets, the speeds of the features cluster around a characteristic value, yet there is a considerable dispersion in the distribution. Orientation variations within the jet cannot fully account for the dispersion, implying that the features have a range of Lorentz factor and/or pattern speed. Very slow pattern speed features are rare, comprising only 4% of the sample, and are more prevalent in radio galaxy and BL Lac jets. We confirm a previously reported upper envelope to the distribution of speed versus beamed luminosity for moving jet features. Below 10{sup 26} W Hz{sup –1} there is a fall-off in maximum speed with decreasing 15 GHz radio luminosity. The general shape of the envelope implies that the most intrinsically powerful AGN jets have a wide range of Lorentz factors up to ?40, while intrinsically weak jets are only mildly relativistic.

  18. Astrometric and Light-travel Time Orbits to Detect Low-mass Companions: A Case Study of the Eclipsing System R Canis Majoris

    E-Print Network [OSTI]

    Ignasi Ribas; Frederic Arenou; Edward F. Guinan

    2002-01-10

    We discuss a method to determine orbital properties and masses of low-mass bodies orbiting eclipsing binaries. The analysis combines long-term eclipse timing modulations (light-travel time or LTT effect) with short-term, high-accuracy astrometry. As an illustration of the method, the results of a comprehensive study of Hipparcos astrometry and over a hundred years of eclipse timings of the Algol-type eclipsing binary R Canis Majoris are presented. A simultaneous solution of the astrometry and the LTTs yields an orbital period of P_12=92.8+/-1.3 yr, an LTT semiamplitude of 2574+/-57 s, an angular semi-major axis of a_12=117+/-5 mas, and values of the orbital eccentricity and inclination of e_12=0.49+/-0.05, and i_12=91.7+/-4.7 deg, respectively. Adopting the total mass of R CMa of M_12=1.24+/-0.05 Mo, the mass of the third body is M_3=0.34+/-0.02 Mo and the semi-major axis of its orbit is a_3=18.7+/-1.7 AU. From its mass, the third body is either a dM3-4 star or, more unlikely, a white dwarf. With the upcoming microarcsecond-level astrometric missions, the technique that we discuss can be successfully applied to detect and characterize long-period planetary-size objects and brown dwarfs around eclipsing binaries. Possibilities for extending the method to pulsating variables or stars with transiting planets are briefly addressed.

  19. Absolute dimensions of the M-type eclipsing binary YY Geminorum (Castor C): a challenge to evolutionary models in the lower main-sequence

    E-Print Network [OSTI]

    Guillermo Torres; Ignasi Ribas

    2001-11-08

    We present new spectroscopic observations of the detached late-type double-lined eclipsing binary YY Gem, a member of the Castor sextuple system and one of the benchmarks for the comparison between observations and stellar evolution theory in the lower main-sequence. In addition, we have re-analyzed existing light curves in several passbands using modern techniques that account for the conspicuous presence of spots. This, combined with the spectroscopy, has yielded a very precise determination of the absolute dimensions of the components, which are virtually identical to each other. We obtain mean values of M=0.5992+/-0.0047 Mo, R=0.6191+/-0.0057 Ro, and Teff=3820+/-100 K. Both the mass and the radius determinations are good to better than 1%. A re-analysis of the Hipparcos transit data for Castor AB has yielded an improved parallax for the system of 66.90+/-0.63 mas. With this, we have estimated the age (~370 Myr) and metal abundance ([Fe/H]~0.0) of YY Gem from isochrone fits to Castor A and B. We have compared the observations of YY Gem with a large number of recent theoretical calculations, and we show that all models underestimate the radius by up to 20%, and most overestimate the effective temperature by 150 K or more. Both of these trends are confirmed by observations of another similar system in the Hyades cluster (V818 Tau). Consequently, theoretical ages for relatively low-mass objects such as T Tauri stars derived from the H-R diagram may be considerably biased. If the radius is used directly as a measure of evolution, ages could be underestimated by as much as a factor of 10 in this mass regime. In view of these discrepancies, absolute ages from essentially all current models for the lower main sequence must be viewed with at least some measure of skepticism. (abridged)

  20. The Milky Way Tomography with SDSS: II. Stellar Metallicity

    E-Print Network [OSTI]

    Zeljko Ivezic; Branimir Sesar; Mario Juric; Nicholas Bond; Julianne Dalcanton; Constance M. Rockosi; Brian Yanny; Heidi J. Newberg; Timothy C. Beers; Carlos Allende Prieto; Ron Wilhelm; Young Sun Lee; Thirupathi Sivarani; John E. Norris; Coryn A. L. Bailer-Jones; Paola Re Fiorentin; David Schlegel; Alan Uomoto; Robert H. Lupton; Gillian R. Knapp; James E. Gunn; Kevin R. Covey; J. Allyn Smith; Gajus Miknaitis; Mamoru Doi; Masayuki Tanaka; Masataka Fukugita; Steve Kent; Douglas Finkbeiner; Jeffrey A. Munn; Jeffrey R. Pier; Tom Quinn; Suzanne Hawley; Scott Anderson; Furea Kiuchi; Alex Chen; James Bushong; Harkirat Sohi; Daryl Haggard; Amy Kimball; John Barentine; Howard Brewington; Mike Harvanek; Scott Kleinman; Jurek Krzesinski; Dan Long; Atsuko Nitta; Stephanie Snedden; Brian Lee; Hugh Harris; Jonathan Brinkmann; Donald P. Schneider; Donald G. York

    2008-04-24

    Using effective temperature and metallicity derived from SDSS spectra for ~60,000 F and G type main sequence stars (0.2mas/yr, for about 200 million F/G dwarf stars within a distance limit of ~100 kpc (g<23.5). [abridged

  1. Concurrent Collections (CnC): A new approach to parallel programming

    ScienceCinema (OSTI)

    None

    2011-10-06

    A common approach in designing parallel languages is to provide some high level handles to manipulate the use of the parallel platform. This exposes some aspects of the target platform, for example, shared vs. distributed memory. It may expose some but not all types of parallelism, for example, data parallelism but not task parallelism. This approach must find a balance between the desire to provide a simple view for the domain expert and provide sufficient power for tuning. This is hard for any given architecture and harder if the language is to apply to a range of architectures. Either simplicity or power is lost. Instead of viewing the language design problem as one of providing the programmer with high level handles, we view the problem as one of designing an interface. On one side of this interface is the programmer (domain expert) who knows the application but needs no knowledge of any aspects of the platform. On the other side of the interface is the performance expert (programmer or program) who demands maximal flexibility for optimizing the mapping to a wide range of target platforms (parallel / serial, shared / distributed, homogeneous / heterogeneous, etc.) but needs no knowledge of the domain. Concurrent Collections (CnC) is based on this separation of concerns. The talk will present CnC and its benefits. About the speaker Kathleen Knobe has focused throughout her career on parallelism especially compiler technology, runtime system design and language design. She worked at Compass (aka Massachusetts Computer Associates) from 1980 to 1991 designing compilers for a wide range of parallel platforms for Thinking Machines, MasPar, Alliant, Numerix, and several government projects. In 1991 she decided to finish her education. After graduating from MIT in 1997, she joined Digital Equipment?s Cambridge Research Lab (CRL). She stayed through the DEC/Compaq/HP mergers and when CRL was acquired and absorbed by Intel. She currently works in the Software and Services Group / Technology Pathfinding and Innovation.

  2. DISCOVERY OF H? EMISSION FROM THE CLOSE COMPANION INSIDE THE GAP OF TRANSITIONAL DISK HD 142527

    SciTech Connect (OSTI)

    Close, L. M.; Follette, K. B.; Males, J. R.; Apai, D.; Morzinski, K.; Rodigas, T. J.; Hinz, P.; Bailey, V.; Puglisi, A.; Xompero, M.; Briguglio, R.; Najita, J.; Weinberger, A. J.

    2014-02-01

    We utilized the new high-order 585 actuator Magellan Adaptive Optics system (MagAO) to obtain very high-resolution visible light images of HD 142527 with MagAO's VisAO science camera. In the median seeing conditions of the 6.5 m Magellan telescope (0.''5–0.''7), we find MagAO delivers 24%-19% Strehl at H? (0.656 ?m). We detect a faint companion (HD 142527B) embedded in this young transitional disk system at just 86.3 ± 1.9 mas (?12 AU) from the star. The companion is detected in both H? and a continuum filter (?mag = 6.33 ± 0.20 mag at H? and 7.50 ± 0.25 mag in the continuum filter). This provides confirmation of the tentative companion discovered by Biller and co-workers with sparse aperture masking at the 8 m Very Large Telescope. The H? emission from the ?0.25 solar mass companion (EW = 180 Å) implies a mass accretion rate of ?5.9 × 10{sup –10} M {sub sun} yr{sup –1} and a total accretion luminosity of 1.2% L {sub sun}. Assuming a similar accretion rate, we estimate that a 1 Jupiter mass gas giant could have considerably better (50-1000×) planet/star contrasts at H? than at the H band (COND models) for a range of optical extinctions (3.4-0 mag). We suggest that ?0.5-5 M {sub jup} extrasolar planets in their gas accretion phase could be much more luminous at H? than in the NIR. This is the motivation for our new MagAO GAPplanetS survey for extrasolar planets.

  3. N-15 NMR spectra of naturally abundant nitrogen in soil and aquatic natural organic matter samples of the International Humic Substances Society

    SciTech Connect (OSTI)

    Thorn, Kevin A.; Cox, Larry G.

    2009-02-28

    The naturally abundant nitrogen in soil and aquatic NOM samples from the International Humic Substances Society has been characterized by solid state CP/MAS ¹?N NMR. Soil samples include humic and fulvic acids from the Elliot soil, Minnesota Waskish peat and Florida Pahokee peat, as well as the Summit Hill soil humic acid and the Leonardite humic acid. Aquatic samples include Suwannee River humic, fulvic and reverse osmosis isolates, Nordic humic and fulvic acids and Pony Lake fulvic acid. Additionally, Nordic and Suwannee River XAD-4 acids and Suwannee River hydrophobic neutral fractions were analyzed. Similar to literature reports, amide/aminoquinone nitrogens comprised the major peaks in the solid state spectra of the soil humic and fulvic acids, along with heterocyclic and amino sugar/terminal amino acid nitrogens. Spectra of aquatic samples, including the XAD-4 acids, contain resolved heterocyclic nitrogen peaks in addition to the amide nitrogens. The spectrum of the nitrogen enriched, microbially derived Pony Lake, Antarctica fulvic acid, appeared to contain resonances in the region of pyrazine, imine and/or pyridine nitrogens, which have not been observed previously in soil or aquatic humic substances by ¹?N NMR. Liquid state ¹?N NMR experiments were also recorded on the Elliot soil humic acid and Pony Lake fulvic acid, both to examine the feasibility of the techniques, and to determine whether improvements in resolution over the solid state could be realized. For both samples, polarization transfer (DEPT) and indirect detection (¹H–¹?N gHSQC) spectra revealed greater resolution among nitrogens directly bonded to protons. The amide/aminoquinone nitrogens could also be observed by direct detection experiments.

  4. Full Three Dimensional Orbits For Multiple Stars on Close Approaches to the Central Supermassive Black Hole

    E-Print Network [OSTI]

    A. M. Ghez; E. Becklin; G. Duchene; S. Hornstein; M. Morris; S. Salim; A. Tanner

    2003-03-07

    With the advent of adaptive optics on the W. M. Keck 10 m telescope, two significant steps forward have been taken in building the case for a supermassive black hole at the center of the Milky Way and understanding the black hole's effect on its environment. Using adaptive optics and speckle imaging to study the motions of stars in the plane of sky with +-~2 mas precision over the past 7 years, we have obtained the first simultaneous orbital solution for multiple stars. Among the included stars, three are newly identified (S0-16, S0-19, S0-20). The most dramatic orbit is that of the newly identified star S0-16, which passed a mere 60 AU from the central dark mass at a velocity of 9,000 km/s in 1999. The orbital analysis results in a new central dark mass estimate of 3.6(+-0.4)x10^6(D/8kpc)^3 Mo. This dramatically strengthens the case for a black hole at the center of our Galaxy, by confining the dark matter to within a radius of 0.0003 pc or 1,000 Rsh and thereby increasing the inferred dark mass density by four orders of magnitude compared to earlier estimates. With the introduction of an adaptive-optics-fed spectrometer, we have obtained the spectra of these high-velocity stars, which suggest that they are massive (~15 Mo), young (<10 Myr) main sequence stars. This presents a major challenge to star formation theories, given the strong tidal forces that prevail over all distances reached by these stars in their current orbits and the difficulty in migrating these stars inward during their lifetime from further out where tidal forces should no longer preclude star formation.

  5. A population of relic intermediate-mass black holes in the halo of the Milky Way

    SciTech Connect (OSTI)

    Rashkov, Valery; Madau, Piero

    2014-01-10

    If 'seed' central black holes were common in the subgalactic building blocks that merged to form present-day massive galaxies, then relic intermediate-mass black holes (IMBHs) should be present in the Galactic bulge and halo. We use a particle tagging technique to dynamically populate the N-body Via Lactea II high-resolution simulation with black holes, and assess the size, properties, and detectability of the leftover population. The method assigns a black hole to the most tightly bound central particle of each subhalo at infall according to an extrapolation of the M {sub BH}-?{sub *} relation, and self-consistently follows the accretion and disruption of Milky Way progenitor dwarfs and their holes in a cosmological 'live' host from high redshift to today. We show that, depending on the minimum stellar velocity dispersion, ? {sub m}, below which central black holes are assumed to be increasingly rare, as many as ?2000 (? {sub m} = 3 km s{sup –1}) or as few as ?70 (? {sub m} = 12 km s{sup –1}) IMBHs may be left wandering in the halo of the Milky Way today. The fraction of IMBHs forced from their hosts by gravitational recoil is ? 20%. We identify two main Galactic subpopulations, 'naked' IMBHs, whose host subhalos were totally destroyed after infall, and 'clothed' IMBHs residing in dark matter satellites that survived tidal stripping. Naked IMBHs typically constitute 40%-50% of the total and are more centrally concentrated. We show that, in the ? {sub m} = 12 km s{sup –1} scenario, the clusters of tightly bound stars that should accompany naked IMBHs would be fainter than m{sub V} = 16 mag, spatially resolvable, and have proper motions of 0.1-10 mas yr{sup –1}. Their detection may provide an observational tool to constrain the formation history of massive black holes in the early universe.

  6. IMAGING DISK DISTORTION OF BE BINARY SYSTEM {delta} SCORPII NEAR PERIASTRON

    SciTech Connect (OSTI)

    Che, X.; Monnier, J. D.; Kraus, S.; Baron, F. [Astronomy Department, University of Michigan, 1034 Dennison Bldg, Ann Arbor, MI 48109-1090 (United States); Tycner, C. [Department of Physics, Central Michigan University, Mount Pleasant, MI 48859 (United States); Zavala, R. T. [US Naval Observatory, Flagstaff Station, 10391 West Naval Observatory Road, Flagstaff, AZ 86001 (United States); Pedretti, E. [European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei Muenchen (Germany); Ten Brummelaar, T.; McAlister, H.; Sturmann, J.; Sturmann, L.; Turner, N. [CHARA Array of Georgia State University, Mount Wilson, CA 91023 (United States); Ridgway, S. T., E-mail: xche@umich.edu [National Optical Astronomy Observatory, NOAO, Tucson, AZ (United States)

    2012-09-20

    The highly eccentric Be binary system {delta} Sco reached periastron during early 2011 July, when the distance between the primary and secondary was a few times the size of the primary disk in the H band. This opened a window of opportunity to study how the gaseous disks around Be stars respond to gravitational disturbance. We first refine the binary parameters with the best orbital phase coverage data from the Navy Precision Optical Interferometer. Then we present the first imaging results of the disk after the periastron, based on seven nights of five telescope observations with the MIRC combiner at the CHARA array. We found that the disk was inclined 27.{sup 0}6 {+-} 6.{sup 0}0 from the plane of the sky, had a half-light radius of 0.49 mas (2.2 stellar radii), and consistently contributed 71.4% {+-} 2.7% of the total flux in the H band from night to night, suggesting no ongoing transfer of material into the disk during the periastron. The new estimation of the periastron passage is UT 2011 July 3 07:00 {+-} 4:30. Re-analysis of archival VLTI-AMBER interferometry data allowed us to determine the rotation direction of the primary disk, constraining it to be inclined either {approx}119 Degree-Sign or {approx}171 Degree-Sign relative to the orbital plane of the binary system. We also detect inner disk asymmetries that could be explained by spot-like emission with a few percent of the disk total flux moving in Keplerian orbits, although we lack sufficient angular resolution to be sure of this interpretation and cannot yet rule out spiral density waves or other more complicated geometries.

  7. Influence of calcium content of biomass-based materials on simultaneous NOx and SO{sub 2} reduction

    SciTech Connect (OSTI)

    Sarma V. Pisupati; Sumeet Bhalla [Pennsylvania State University, University Park, PA (United States). Energy and Mineral Engineering Department

    2008-04-01

    Pyrolysis products of biomass (bio-oils) have been shown to cause a reduction in NOx emissions when used as reburn fuels in combustion systems. When these bio-oils are processed with lime, calcium is ion-exchanged and the product is called BioLime. BioLime, when introduced into a combustion chamber, pyrolyzes and produces volatile products that reduce NOx emissions through reburn mechanisms. Simultaneously, calcium reacts with SO{sub 2} to form calcium sulfate and thus reduces SO{sub 2} emissions. This paper reports the characterization of composition and pyrolysis behavior of two BioLime products and the influence of feedstock on pyrolysis products. Thermogravimetric analysis (TGA) and {sup 13}C-CP/MAS NMR techniques were used to study the composition of two biomass-based materials. The composition of the pyrolysis products of BioLime was determined in a laboratory scale flow reactor. The effect of BioLime composition on NOx and SO{sub 2} reduction performance was evaluated in a 146.5 kW pilot-scale, down fired combustor (DFC). The effect of pyrolysis gas composition on NOx reduction is discussed. The TGA weight loss curves of BioLime samples in an inert atmosphere showed two distinct peaks corresponding to the decomposition of light and heavy components of the BioLime and a third distinct peak corresponding to secondary thermal decomposition of char. The study also showed that BioLime sample with lower content of residual lignin derivatives and lower calcium content produced more volatile compounds upon pyrolysis in the combustor and achieved higher NOx reduction (15%). Higher yields of pyrolysis gases increased the NO reduction potential of BioLime through homogeneous gas phase reactions. Calcium in BioLime samples effectively reduced SO{sub 2} emissions (60-85%). 36 refs., 6 figs., 3 tabs.

  8. Studies of the jet in BL Lacertae. I. Recollimation shock and moving emission features

    SciTech Connect (OSTI)

    Cohen, M. H.; Hovatta, T.; Meier, D. L.; Arshakian, T. G.; Homan, D. C.; Kovalev, Y. Y.; Pushkarev, A. B.; Savolainen, T.

    2014-06-01

    Parsec-scale VLBA images of BL Lac at 15 GHz show that the jet contains a permanent quasi-stationary emission feature 0.26 mas (0.34 pc projected) from the core, along with numerous moving features. In projection, the tracks of the moving features cluster around an axis at a position angle of –166.°6 that connects the core with the standing feature. The moving features appear to emanate from the standing feature in a manner strikingly similar to the results of numerical two-dimensional relativistic magneto-hydrodynamic (RMHD) simulations in which moving shocks are generated at a recollimation shock (RCS). Because of this, and the close analogy to the jet feature HST-1 in M87, we identify the standing feature in BL Lac as an RCS. We assume that the magnetic field dominates the dynamics in the jet, and that the field is predominantly toroidal. From this we suggest that the moving features are compressions established by slow and fast mode magneto-acoustic MHD waves. We illustrate the situation with a simple model in which the slowest moving feature is a slow-mode wave, and the fastest feature is a fast-mode wave. In the model, the beam has Lorentz factor ?{sub beam}{sup gal}?3.5 in the frame of the host galaxy and the fast mode wave has Lorentz factor ?{sub Fwave}{sup beam}?1.6 in the frame of the beam. This gives a maximum apparent speed for the moving features, ?{sub app} = v{sub app}/c = 10. In this model the Lorentz factor of the pattern in the galaxy frame is approximately three times larger than that of the beam itself.

  9. Heterogeneous Recycling in Fast Reactors

    SciTech Connect (OSTI)

    Forget, Benoit; Pope, Michael; Piet, Steven J.; Driscoll, Michael

    2012-07-30

    Current sodium fast reactor (SFR) designs have avoided the use of depleted uranium blankets over concerns of creating weapons grade plutonium. While reducing proliferation risks, this restrains the reactor design space considerably. This project will analyze various blanket and transmutation target configurations that could broaden the design space while still addressing the non-proliferation issues. The blanket designs will be assessed based on the transmutation efficiency of key minor actinide (MA) isotopes and also on mitigation of associated proliferation risks. This study will also evaluate SFR core performance under different scenarios in which depleted uranium blankets are modified to include minor actinides with or without moderators (e.g. BeO, MgO, B4C, and hydrides). This will be done in an effort to increase the sustainability of the reactor and increase its power density while still offering a proliferation resistant design with the capability of burning MA waste produced from light water reactors (LWRs). Researchers will also analyze the use of recycled (as opposed to depleted) uranium in the blankets. The various designs will compare MA transmutation efficiency, plutonium breeding characteristics, proliferation risk, shutdown margins and reactivity coefficients with a current reference sodium fast reactor design employing homogeneous recycling. The team will also evaluate the out-of-core accumulation and/or burn-down rates of MAs and plutonium isotopes on a cycle-by-cycle basis. This cycle-by-cycle information will be produced in a format readily usable by the fuel cycle systems analysis code, VISION, for assessment of the sustainability of the deployment scenarios.

  10. Trigonometric distance and proper motion of IRAS 20056+3350: a massive star-forming region on the solar circle

    SciTech Connect (OSTI)

    Burns, Ross A.; Handa, Toshihiro; Omodaka, Toshihiro; Nakagawa, Akiharu; Nakanishi, Hiroyuki [Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Kôrimoto, Kagoshima, Kagoshima 890-0065 (Japan); Nagayama, Takumi [Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hayashi, Masahiko [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Shizugami, Makoto, E-mail: RossBurns88@MilkyWay.sci.Kagoshima-u.ac.jp [Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, 2-12 Hoshi-ga-oka, Mizusawa-ku, Oshu, Iwate 023-0861 (Japan)

    2014-12-10

    We report our measurement of the trigonometric distance and proper motion of IRAS 20056+3350, obtained from the annual parallax of H{sub 2}O masers. Our distance of D=4.69{sub ?0.51}{sup +0.65} kpc, which is 2.8 times larger than the near kinematic distance adopted in the literature, places IRAS 20056+3350 at the leading tip of the Local arm and proximal to the solar circle. Using our distance, we reevaluate past observations to reveal IRAS 20056+3350 as a site of massive star formation at a young stage of evolution. This result is consistent with the spectral energy distribution of the source evaluated with published photometric data from UKIDSS, WISE, AKARI, IRAS, and the submillimeter continuum. Both analytical approaches reveal the luminosity of the region to be 2.4 × 10{sup 4} L {sub ?}, and suggest that IRAS 20056+3350 is forming an embedded star of ?16 M {sub ?}. We estimated the proper motion of IRAS 20056+3350 to be (?{sub ?}cos ?, ?{sub ?}) = (–2.62 ± 0.33, –5.65 ± 0.52) mas yr{sup –1} from the group motion of H{sub 2}O masers, and use our results to estimate the angular velocity of Galactic rotation at the Galactocentric distance of the Sun, ?{sub 0} = 29.75 ± 2.29 km s{sup –1} kpc{sup –1}, which is consistent with the values obtained for other tangent point and solar circle objects.

  11. Resolving the ionized wind of the post-Red Supergiant IRC +10 420 with VLTI/AMBER

    E-Print Network [OSTI]

    W. J. de Wit; R. D. Oudmaijer; M. A. T. Groenewegen; M. G. Hoare; F. Malbet; ;

    2007-11-30

    The paper investigates the milli-arcsecond scale structure of the present-day mass-loss of the post-Red Supergiant IRC+10420. We use three telescopes of the VLT Interferometer in combination with the AMBER near-infrared beam combiner to measure spectrally dispersed correlated fluxes in the K-band around the Br gamma transition. The resulting visibilities are compared to the predicted visibilities of emission structures with various simple models in order to infer the size of the observed emission region. The Br gamma line is resolved by VLTI+AMBER on all three baselines, with the maximum projected baseline extending 69 meter and a P.A. ranging between 10 and 30 degrees. A differential phase between line and continuum is detected on the longest baseline. The Br gamma emission region is found to have a diameter of 3.3 milli-arcseconds (FWHM), when compared to a Gaussian intensity distribution. A uniform disk and a ring-like intensity distribution do not fit the line visibilities. Comparing the AMBER equivalent width of Br gamma with measurements from various epochs, we find that the stellar photosphere contributes about 60% of the total continuum light at 2.2 micron. The remaining 40% continuum emission is found on scales larger than the 66mas AMBER field of view. Using simple arguments, and assuming optically thick line emission, we find that the line emitting region is elongated. We briefly discuss the possibilities whether such a structure is due to a bi-polar flow or a circumstellar disk. (Abridged).

  12. Smoke Signals From IRC +10216: 1. Milliarcsecond Proper Motions of the Dust

    E-Print Network [OSTI]

    P. G. Tuthill; J. D. Monnier; W. C. Danchi; B. Lopez

    2000-03-21

    The results of a 7-epoch interferometric imaging study, at wavelengths in the near-infrared K-band, of the carbon star IRC +10216 are presented. The use of non- and partially-redundant aperture masking techniques on the 10-m Keck-I telescope has allowed us to produce images of the innermost regions of the circumstellar dust envelope with unprecedented detail. With roughly twice the resolving power of previous work, the complex asymmetric structures reported within the central 0.5 arcsec (20 stellar radii) have been imaged at the size scale of the stellar disk itself (about 50 mas). A prominent dark lane at a position angle of approximately 120 deg is suggested to be an optically thick disk or torus of dust which could help to explain IRC +10216's well-known bipolarity at a position angle of 20 deg. Observations spanning more than a pulsational cycle (638 days) have revealed significant temporal evolution of the nebula, including the outward motion of bright knots and clumps. Registering these displacements against the compact bright core, which we tentatively identify as marking the location of the star, has allowed us to determine the apparent angular velocity at a number of points. The magnitudes of the proper motions were found to be in agreement with current estimates of the stellar distance and radial velocity. Higher outflow speeds were found for features with greater separation from the core. This is consistent with acceleration taking place over the region sampled by the measurements, however alternate interpretations are also presented. Although a number of changes of morphology were found, none were clearly interpreted as the condensation of new dust over the pulsation cycle.

  13. SU-E-I-57: Evaluation and Optimization of Effective-Dose Using Different Beam-Hardening Filters in Clinical Pediatric Shunt CT Protocol

    SciTech Connect (OSTI)

    Gill, K; Aldoohan, S; Collier, J

    2014-06-01

    Purpose: Study image optimization and radiation dose reduction in pediatric shunt CT scanning protocol through the use of different beam-hardening filters Methods: A 64-slice CT scanner at OU Childrens Hospital has been used to evaluate CT image contrast-to-noise ratio (CNR) and measure effective-doses based on the concept of CT dose index (CTDIvol) using the pediatric head shunt scanning protocol. The routine axial pediatric head shunt scanning protocol that has been optimized for the intrinsic x-ray tube filter has been used to evaluate CNR by acquiring images using the ACR approved CT-phantom and radiation dose CTphantom, which was used to measure CTDIvol. These results were set as reference points to study and evaluate the effects of adding different filtering materials (i.e. Tungsten, Tantalum, Titanium, Nickel and Copper filters) to the existing filter on image quality and radiation dose. To ensure optimal image quality, the scanner routine air calibration was run for each added filter. The image CNR was evaluated for different kVps and wide range of mAs values using above mentioned beam-hardening filters. These scanning protocols were run under axial as well as under helical techniques. The CTDIvol and the effective-dose were measured and calculated for all scanning protocols and added filtration, including the intrinsic x-ray tube filter. Results: Beam-hardening filter shapes energy spectrum, which reduces the dose by 27%. No noticeable changes in image low contrast detectability Conclusion: Effective-dose is very much dependent on the CTDIVol, which is further very much dependent on beam-hardening filters. Substantial reduction in effective-dose is realized using beam-hardening filters as compare to the intrinsic filter. This phantom study showed that significant radiation dose reduction could be achieved in CT pediatric shunt scanning protocols without compromising in diagnostic value of image quality.

  14. Trivalent Lanthanide/Actinide Separation Using Aqueous-Modified TALSPEAK Chemistry

    SciTech Connect (OSTI)

    Travis S. Grimes; Richard D. Tillotson; Leigh R. Martin

    2014-05-01

    TALSPEAK is a liquid/liquid extraction process designed to separate trivalent lanthanides (Ln3+) from minor actinides (MAs) Am3+ and Cm3+. Traditional TALSPEAK organic phase is comprised of a monoacidic dialkyl bis(2-ethylhexyl)phosphoric acid extractant (HDEHP) in diisopropyl benzene (DIPB). The aqueous phase contains a soluble aminopolycarboxylate diethylenetriamine-N,N,N’,N”,N”-pentaacetic acid (DTPA) in a concentrated (1.0-2.0 M) lactic acid (HL) buffer with the aqueous acidity typically adjusted to pH 3.0. TALSPEAK balances the selective complexation of the actinides by DTPA against the electrostatic attraction of the lanthanides by the HDEHP extractant to achieve the desired trivalent lanthanide/actinide group separation. Although TALSPEAK is considered a successful separations scheme, recent fundamental studies have highlighted complex chemical interactions occurring in the aqueous and organic phases during the extraction process. Previous attempts to model the system have shown thermodynamic models do not accurately predict the observed extraction trends in the p[H+] range 2.5-4.8. In this study, the aqueous phase is modified by replacing the lactic acid buffer with a variety of simple and longer-chain amino acid buffers. The results show successful trivalent lanthanide/actinide group separation with the aqueous-modified TALSPEAK process at pH 2. The amino acid buffer concentrations were reduced to 0.5 M (at pH 2) and separations were performed without any effect on phase transfer kinetics. Successful modeling of the aqueous-modified TALSPEAK process (p[H+] 1.6-3.1) using a simplified thermodynamic model and an internally consistent set of thermodynamic data is presented.

  15. Zeolite Y adsorbents with high vapor uptake capacity and robust cycling stability for potential applications in advanced adsorption heat pumps

    SciTech Connect (OSTI)

    Li, XS; Narayanan, S; Michaelis, VK; Ong, TC; Keeler, EG; Kim, H; Mckay, IS; Griffin, RG; Wang, EN

    2015-01-01

    Modular and compact adsorption heat pumps (AHPs) promise an energy-efficient alternative to conventional vapor compression based heating, ventilation and air conditioning systems. A key element in the advancement of AHPs is the development of adsorbents with high uptake capacity, fast intracrystalline diffusivity and durable hydrothermal stability. Herein, the ion exchange of NaY zeolites with ingoing Mg2+ ions is systematically studied to maximize the ion exchange degree (IED) for improved sorption performance. It is found that beyond an ion exchange threshold of 64.1%, deeper ion exchange does not benefit water uptake capacity or characteristic adsorption energy, but does enhance the vapor diffusivity. In addition to using water as an adsorbate, the uptake properties of Mg, Na-Y zeolites were investigated using 20 wt.% MeOH aqueous solution as a novel anti-freeze adsorbate, revealing that the MeOH additive has an insignificant influence on the overall sorption performance. We also demonstrated that the lab-scale synthetic scalability is robust, and that the tailored zeolites scarcely suffer from hydrothermal stability even after successive 108-fold adsorption/desorption cycles. The samples were analyzed using N-2 sorption, Al-27/Si-29 MAS NMR spectroscopy, ICP-AES, dynamic vapor sorption, SEM, Fick's 2nd law and D-R equation regressions. Among these, close examination of sorption isotherms for H2O and N-2 adsorbates allows us to decouple and extract some insightful information underlying the complex water uptake phenomena. This work shows the promising performance of our modified zeolites that can be integrated into various AHP designs for buildings, electronics, and transportation applications. (C) 2014 Elsevier Inc. All rights reserved.

  16. High frequency VLBI observations of the scatter broadened quasar B2005+403

    E-Print Network [OSTI]

    K. E. Gabanyi; T. P. Krichbaum; S. Britzen; U. Bach; E. Ros; A. Witzel; J. A. Zensus

    2006-01-17

    The quasar B2005+403 located behind the Cygnus region, is a suitable object for studying the interplay between propagation effects, which are extrinsic to the source and source intrinsic variability. On the basis of VLBI experiments performed at 1.6, 5, 8, 15, 22, and 43GHz between 1992-2003 and parallel multi-frequency monitoring of the total flux density, we investigated the variability of total flux density and source structure. Below 8 GHz, the point-like VLBI source is affected by scatter-broadening of the turbulent interstellar medium, which is located along the line of sight and likely associated with the Cygnus region. We present and discuss the measured frequency dependence of the source size, which shows a power-law with slope of -1.91+/-0.05. From the measured scattering angle at 1GHz of 77.1+/-4.0mas a SM=0.43+/-0.04 m^{-20/3} kpc is derived, consistent with the general properties of the ISM in this direction. The decreasing effect of angular broadening towards higher frequencies allows to study the internal structure of the source. Above 8GHz new VLBI observations reveal a one-sided slightly south-bending core-jet structure, with stationary and apparent superluminally moving jet components. The jet components move on non-ballistic trajectories. In AGN, total flux density variations are often related to the emergence of new VLBI components. However, during almost eleven years no new component was ejected in B2005+403. In the flux density variability a trough is observed at 5-37 GHz between 1996 and 2001. This can be explained as a blending effect of jet component fluxes. Dense in time sampled flux density monitoring observations reveal intra-day variability at 1.6GHz impling a second, less dense or turbulent scattering screen at few to hundred parsec distance.

  17. Multi-frequency optical-depth maps and the case for free-free absorption in two compact symmetric radio sources: The CSO candidate J1324 + 4048 and the CSO J0029 + 3457

    SciTech Connect (OSTI)

    Marr, J. M.; Read, J.; Morris, A. O.; Perry, T. M.; Taylor, G. B.

    2014-01-10

    We obtained dual-polarization very long baseline interferometry observations at six frequencies of the compact symmetric object J0029 + 3457 and the compact symmetric object candidate J1324 + 4048. By comparing the three lower-frequency maps with extrapolations of the high-frequency maps, we produced maps of the optical depth as a function of frequency. The morphology of the optical-depth maps of J1324 + 4048 is strikingly smooth, suggestive of a foreground screen of absorbing gas. The spectra at the intensity peaks fit a simple free-free absorption (FFA) model, with ?{sub ?}{sup 2}?2, better than a simple synchrotron self-absorption model, in which ?{sub ?}{sup 2}?3.5--5.5. We conclude that the case for FFA in J1324 + 4048 is strong. The optical-depth maps of J0029 + 3457 exhibit structure, but the morphology does not correlate with that in the intensity maps. The fit of the spectra at the peaks to a simple FFA model yields ?{sub ?}{sup 2}?1, but because the turnover is gradual, the fit is relatively insensitive to the input parameters. We find that FFA by a thin amount of gas in J0029 + 3457 is likely but not definitive. One compact feature in J0029 + 3457 has an inverted spectrum even at the highest frequencies. We infer this to be the location of the core and estimate an upper limit to the magnetic field of order 3 Gauss at a radius of order 1 pc. In comparison with maps from observations at earlier epochs, no apparent growth in either J1324 + 4048 or J0029 + 3457 is apparent, with upper limits of 0.03 and 0.02 mas yr{sup –1}, corresponding to maximum linear separation speeds of 0.6c and 0.4c.

  18. Charge Compensation in RE3+ (RE = Eu, Gd) and M+ (M = Li, Na, K) Co-Doped Alkaline Earth Nanofluorides Obtained by Microwave Reaction with Reactive Ionic Liquids Leading to Improved Optical Properties

    SciTech Connect (OSTI)

    Lorbeer, C [Ruhr-Universitat Bochum; Behrends, F [Westfalische Wilhelsm-Universitat Munster; Cybinska, J [Ruhr Universitat Bochum; Eckert, H [Westfalische Wilhelsm-Universitat Munster; Mudring, Anja -V [Ames Laboratory

    2014-01-01

    Alkaline earth fluorides are extraordinarily promising host matrices for phosphor materials with regard to rare earth doping. In particular, quantum cutting materials, which might considerably enhance the efficiency of mercury-free fluorescent lamps or SC solar cells, are often based on rare earth containing crystalline fluorides such as NaGdF4, GdF3 or LaF3. Substituting most of the precious rare earth ions and simultaneously retaining the efficiency of the phosphor is a major goal. Alkaline earth fluoride nanoparticles doped with trivalent lanthanide ions (which are required for the quantum cutting phenomenon) were prepared via a microwave assisted method in ionic liquids. As doping trivalent ions into a host with divalent cations requires charge compensation, this effect was thoroughly studied by powder X-ray and electron diffraction, luminescence spectroscopy and 23Na, 139La and 19F solid state NMR spectroscopy. Monovalent alkali ions were codoped with the trivalent lanthanide ions to relieve stress and achieve a better crystallinity and higher quantum cutting abilities of the prepared material. 19F-magic angle spinning (MAS)-NMR-spectra, assisted by 19F{23Na} rotational echo double resonance (REDOR) studies, reveal distinct local fluoride environments, the populations of which are discussed in relation to spatial distribution and clustering models. In the co-doped samples, fluoride species having both Na+ and La3+ ions within their coordination sphere can be identified and quantified. This interplay of mono- and trivalent ions in the CaF2 lattice appears to be an efficient charge compensation mechanism that allows for improved performance characteristics of such co-doped phosphor materials.

  19. Candidate gravitational microlensing events for future direct lens imaging

    SciTech Connect (OSTI)

    Henderson, C. B.; Gould, A.; Gaudi, B. S. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Park, H.; Han, C. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Sumi, T.; Koshimoto, N. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Bozza, V. [Department of Physics, University of Salerno, I-84084 Fisciano (Italy); Abe, F.; Fukunaga, D.; Itow, Y.; Masuda, K. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Bond, I. A.; Ling, C. H. [Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland 0745 (New Zealand); Botzler, C. S.; Freeman, M. [Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001 (New Zealand); Fukui, A. [School of Chemical and Physical Sciences, Victoria University, Wellington 6140 (New Zealand); Collaboration: MOA Collaboration; OGLE Collaboration; ?FUN Collaboration; RoboNet Collaboration; and others

    2014-10-10

    The mass of the lenses giving rise to Galactic microlensing events can be constrained by measuring the relative lens-source proper motion and lens flux. The flux of the lens can be separated from that of the source, companions to the source, and unrelated nearby stars with high-resolution images taken when the lens and source are spatially resolved. For typical ground-based adaptive optics (AO) or space-based observations, this requires either inordinately long time baselines or high relative proper motions. We provide a list of microlensing events toward the Galactic bulge with high relative lens-source proper motion that are therefore good candidates for constraining the lens mass with future high-resolution imaging. We investigate all events from 2004 to 2013 that display detectable finite-source effects, a feature that allows us to measure the proper motion. In total, we present 20 events with ? ? 8 mas yr{sup –1}. Of these, 14 were culled from previous analyses while 6 are new, including OGLE-2004-BLG-368, MOA-2005-BLG-36, OGLE-2012-BLG-0211, OGLE-2012-BLG-0456, MOA-2012-BLG-532, and MOA-2013-BLG-029. In ?12 yr from the time of each event the lens and source of each event will be sufficiently separated for ground-based telescopes with AO systems or space telescopes to resolve each component and further characterize the lens system. Furthermore, for the most recent events, comparison of the lens flux estimates from images taken immediately to those estimated from images taken when the lens and source are resolved can be used to empirically check the robustness of the single-epoch method currently being used to estimate lens masses for many events.

  20. A characterization and evaluation of coal liquefaction process streams. Quarterly technical progress report, July 1--September 30, 1995

    SciTech Connect (OSTI)

    Robbins, G.A.; Brandes, S.D.; Winschel, R.A.; Burke, F.P.

    1995-12-01

    The objectives of this project are to support the DOE direct coal liquefaction process development program and to improve the useful application of analytical chemistry to direct coal liquefaction process development. Independent analyses by well-established methods will be obtained of samples produced in direct coal liquefaction processes under evaluation by DOE. Additionally, analytical instruments and techniques which are currently underutilized for the purpose of examining coal-derived samples will be evaluated. The data obtained from this study will be used to help guide current process development and to develop an improved data base on coal and coal liquids properties. A sample bank will be established and maintained for use in this project and will be available for use by other researchers. The reactivity of the non-distillable resids toward hydrocracking at liquefaction conditions (i.e., resid reactivity) will be examined. From the literature and data experimentally obtained, a mathematical kinetic model of resid conversion will be constructed. It is anticipated that such a model will provide insights useful for improving process performance and thus the economics of direct coal liquefaction. Some of the contract activities for this quarter are: We completed many of the analyses on the 81 samples received from HTI bench-scale run CMSL-9, in which coal, coal/mixed plastics, and coal/high density polyethylene were fed; Liquid chromatographic separations of the 15 samples in the University of Delaware sample set were completed; and WRI completed CP/MAS {sup 13}C-NMR analyses on the Delaware sample set.

  1. MO-E-17A-03: Monte Carlo CT Dose Calculation: A Comparison Between Experiment and Simulation Using ARCHER-CT

    SciTech Connect (OSTI)

    Liu, T; Du, X; Su, L; Gao, Y; Ji, W; Xu, X; Zhang, D; Shi, J; Liu, B; Kalra, M

    2014-06-15

    Purpose: To compare the CT doses derived from the experiments and GPU-based Monte Carlo (MC) simulations, using a human cadaver and ATOM phantom. Methods: The cadaver of an 88-year old male and the ATOM phantom were scanned by a GE LightSpeed Pro 16 MDCT. For the cadaver study, the Thimble chambers (Model 10×5?0.6CT and 10×6?0.6CT) were used to measure the absorbed dose in different deep and superficial organs. Whole-body scans were first performed to construct a complete image database for MC simulations. Abdomen/pelvis helical scans were then conducted using 120/100 kVps, 300 mAs and a pitch factor of 1.375:1. For the ATOM phantom study, the OSL dosimeters were used and helical scans were performed using 120 kVp and x, y, z tube current modulation (TCM). For the MC simulations, sufficient particles were run in both cases such that the statistical errors of the results by ARCHER-CT were limited to 1%. Results: For the human cadaver scan, the doses to the stomach, liver, colon, left kidney, pancreas and urinary bladder were compared. The difference between experiments and simulations was within 19% for the 120 kVp and 25% for the 100 kVp. For the ATOM phantom scan, the doses to the lung, thyroid, esophagus, heart, stomach, liver, spleen, kidneys and thymus were compared. The difference was 39.2% for the esophagus, and within 16% for all other organs. Conclusion: In this study the experimental and simulated CT doses were compared. Their difference is primarily attributed to the systematic errors of the MC simulations, including the accuracy of the bowtie filter modeling, and the algorithm to generate voxelized phantom from DICOM images. The experimental error is considered small and may arise from the dosimeters. R01 grant (R01EB015478) from National Institute of Biomedical Imaging and Bioengineering.

  2. ASTROMETRY AND RADIAL VELOCITIES OF THE PLANET HOST M DWARF GJ 317: NEW TRIGONOMETRIC DISTANCE, METALLICITY, AND UPPER LIMIT TO THE MASS OF GJ 317b

    SciTech Connect (OSTI)

    Anglada-Escude, Guillem; Boss, Alan P.; Weinberger, Alycia J.; Butler, R. Paul; Thompson, Ian B.; Vogt, Steven S.; Rivera, Eugenio J.

    2012-02-10

    We have obtained precision astrometry of the planet host M dwarf GJ 317 in the framework of the Carnegie Astrometric Planet Search project. The new astrometric measurements give a distance determination of 15.3 pc, 65% further than previous estimates. The resulting absolute magnitudes suggest that it is metal-rich and more massive than previously assumed. This result strengthens the correlation between high metallicity and the presence of gas giants around low-mass stars. At 15.3 pc, the minimal astrometric amplitude for planet candidate GJ 317b is 0.3 mas (edge-on orbit), just below our astrometric sensitivity. However, given the relatively large number of observations and good astrometric precision, a Bayesian Monte Carlo Markov Chain analysis indicates that the mass of planet b has to be smaller than twice the minimum mass with a 99% confidence level, with a most likely value of 2.5 M{sub Jup}. Additional radial velocity (RV) measurements obtained with Keck by the Lick-Carnegie Planet search program confirm the presence of an additional very long period planet candidate, with a period of 20 years or more. Even though such an object will imprint a large astrometric wobble on the star, its curvature is yet not evident in the astrometry. Given high metallicity, and the trend indicating that multiple systems are rich in low-mass companions, this system is likely to host additional low-mass planets in its habitable zone that can be readily detected with state-of-the-art optical and near-infrared RV measurements.

  3. First images of 6.7-GHz methanol masers in DR21(OH) and DR21(OH)N

    E-Print Network [OSTI]

    L. Harvey-Smith; R. Soria-Ruiz; A. Duarte-Cabral; R. J. Cohen

    2007-11-18

    The first images of 6.7-GHz methanol masers in the massive star-forming regions DR21(OH) and DR21(OH)N are presented. By measuring the shapes, radial velocities and polarization properties of these masers it is possible to map out the structure, kinematics and magnetic fields in the molecular gas that surrounds newly-formed massive stars. The intrinsic angular resolution of the observations was 43 mas (~100 AU at the distance of DR21), but structures far smaller than this were revealed by employing a non-standard mapping technique. This technique was used in an attempt to identify the physical structure (e.g. disc, outflow, shock) associated with the methanol masers. Two distinct star-forming centres were identified. In DR21(OH) the masers had a linear morphology, and the individual maser spots each displayed an internal velocity gradient in the same direction as the large-scale structure. They were detected at the same position as the OH 1.7-GHz ground-state masers, close to the centre of an outflow traced by CO and class I methanol masers. The shape and velocity gradients of the masers suggests that they probably delineate a shock. In DR21(OH)N the methanol masers trace an arc with a double-peaked profile and a complex velocity gradient. This velocity gradient closely resembles that of a Keplerian disc. The masers in the arc are 4.5% linearly polarized, with a polarization angle that indicates that the magnetic field direction is roughly perpendicular to the large-scale magnetic field in the region (indicated by lower angular resolution measurements of the CO and dust polarization). The suitability of channel-by-channel centroid mapping is discussed as an improved and viable means to maximise the information gained from the data.

  4. Surfactant-assisted synthesis of hybrid lithium iron phosphate nanoparticles for enhancing electrochemical performance

    SciTech Connect (OSTI)

    Min Kim, Jung [Division of Materials Science, Korea Basic Science Institute (KBSI), Daejeon 305-806 (Korea, Republic of); Yi, Gi-Ra [Department of Polymer Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Chang Lee, Soon; Moon Lee, Sang; Jo, Younghun [Division of Materials Science, Korea Basic Science Institute (KBSI), Daejeon 305-806 (Korea, Republic of); Kang, Hyun-Wook [Graduate School of Analytical Science and Technology (GRAST), Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lee, Gaehang, E-mail: ghlee@kbsi.re.kr [Division of Materials Science, Korea Basic Science Institute (KBSI), Daejeon 305-806 (Korea, Republic of); Jin Kim, Hae, E-mail: hansol@kbsi.re.kr [Division of Materials Science, Korea Basic Science Institute (KBSI), Daejeon 305-806 (Korea, Republic of); Graduate School of Analytical Science and Technology (GRAST), Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2013-01-15

    Hybrid nanoparticles of LiFePO{sub 4} with carbon and lithium phosphates were synthesized through organic-inorganic co-assembly procedure using a triblock copolymer (F108 or P123). We found that the triblock copolymers play a critical role in controlling size of hybrid particle and the degree of crystallinity of the inorganic nanostructures. The hybrid using P-123 had more graphitic carbon which resulted in fast electron mobility. Also, magic angle spinning nuclear magnetic resonance (MAS-NMR) revealed that the crystallinity of the hybrid using P123 is higher than that using F108 which is not measurable in X-ray diffraction. Electrochemical performance of the hybrid using P123 as a cathode material in Li-ion batteries showed superior rate capability at 20 C of charging rate and 2 C of discharging rate without capacity loss, in which discharge capacity was 102 mAh/g. - Graphical abstract: Hybrid nanoparticles were synthesized through organic-inorganic co-assembly based on synthetic procedure of mesoporous materials. P123-LFP showed superior high-rate capability at a 20 C charging rate and 2 C discharging rate without capacity loss in Li-ion battery. Highlights: Black-Right-Pointing-Pointer LiFePO{sub 4} nanohybrids are synthesized through the organic-inorganic co-assembly method. Black-Right-Pointing-Pointer Copolymers (F108 or P123) serve as structure directing agents and a carbon source. Black-Right-Pointing-Pointer P123 produces more graphitic carbon and higher crystalline nanohybrids. Black-Right-Pointing-Pointer Nanohybrids using P123 show superior rate capability in Li-ion battery.

  5. DISCOVERY, PROGENITOR AND EARLY EVOLUTION OF A STRIPPED ENVELOPE SUPERNOVA iPTF13bvn

    SciTech Connect (OSTI)

    Cao, Yi; Horesh, Assaf; Kulkarni, S. R. [Astronomy Department, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States)] [Astronomy Department, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Kasliwal, Mansi M. [The Observatories, Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)] [The Observatories, Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Arcavi, Iair; Gal-Yam, Avishay; Gorbikov, Evgeny; Ofek, Eran O.; Yaron, Ofer [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel)] [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel); Hancock, Paul [Sydney Institute for Astronomy (SIfA), School of Physics, The University of Sydney, NSW 2006 (Australia)] [Sydney Institute for Astronomy (SIfA), School of Physics, The University of Sydney, NSW 2006 (Australia); Valenti, Stefano; Graham, Melissa; Howell, D. Andrew [Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States)] [Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States); Cenko, S. Bradley [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States)] [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Sand, David [Department of Physics, Texas Tech University, Lubbock, TX 79409 (United States)] [Department of Physics, Texas Tech University, Lubbock, TX 79409 (United States); Silverman, Jeffrey M.; Wheeler, J. Craig; Marion, G. H. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)] [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Walker, Emma S. [Department of Physics, Yale University, New Haven, CT 06511-8499 (United States)] [Department of Physics, Yale University, New Haven, CT 06511-8499 (United States); Mazzali, Paolo, E-mail: ycao@astro.caltech.edu [INAF-Padova Astronomical Observatory, Vicolo dell'Osservatorio 5, I-35122 Padova (Italy)] [INAF-Padova Astronomical Observatory, Vicolo dell'Osservatorio 5, I-35122 Padova (Italy); and others

    2013-09-20

    The intermediate Palomar Transient Factory reports our discovery of a young supernova, iPTF13bvn, in the nearby galaxy, NGC 5806 (22.5 Mpc). Our spectral sequence in the optical and infrared suggests a Type Ib classification. We identify a blue progenitor candidate in deep pre-explosion imaging within a 2? error circle of 80 mas (8.7 pc). The candidate has an M{sub B} luminosity of –5.52 ± 0.39 mag and a B – I color of 0.25 ± 0.25 mag. If confirmed by future observations, this would be the first direct detection for a progenitor of a Type Ib. Fitting a power law to the early light curve, we find an extrapolated explosion date around 0.6 days before our first detection. We see no evidence of shock cooling. The pre-explosion detection limits constrain the radius of the progenitor to be smaller than a few solar radii. iPTF13bvn is also detected in centimeter and millimeter wavelengths. Fitting a synchrotron self-absorption model to our radio data, we find a mass-loading parameter of 1.3×10{sup 12} g cm{sup –1}. Assuming a wind velocity of 10{sup 3} km s{sup –1}, we derive a progenitor mass-loss rate of 3 × 10{sup –5} M {sub ?} yr{sup –1}. Our observations, taken as a whole, are consistent with a Wolf-Rayet progenitor of the supernova iPTF13bvn.

  6. Microlens OGLE-2005-BLG-169 Implies Cool Neptune-Like Planets are Common

    E-Print Network [OSTI]

    A. Gould; A. Udalski; D. An; D. P. Bennett; A. -Y. Zhou; S. Dong; N. J. Rattenbury; B. S. Gaudi; P. C. M. Yock; I. A. Bond; G. W. Christie; K. Horne; J. Anderson; K. Z. Stanek; D. L. DePoy; C. Han; J. McCormick; B. -G. Park; R. W. Pogge; S. D. Poindexter; I. Soszynski; M. K. Szymanski; M. Kubiak; G. Pietrzynski; O. Szewczyk; L. Wyrzykowski; K. Ulaczyk; B. Paczynski; D. M. Bramich; C. Snodgrass; I. A. Steele; M. J. Burgdorf; M. F. Bode; C. S. Botzler; S. Mao; S. C. Swaving

    2006-03-10

    We detect a Neptune mass-ratio (q~8e-5) planetary companion to the lens star in the extremely high-magnification (A~800) microlensing event OGLE-2005-BLG-169. If the parent is a main-sequence star, it has mass M~0.5 M_sun implying a planet mass of ~13 M_earth and projected separation of ~2.7 AU. When intensely monitored over their peak, high-magnification events similar to OGLE-2005-BLG-169 have nearly complete sensitivity to Neptune mass-ratio planets with projected separations of 0.6 to 1.6 Einstein radii, corresponding to 1.6--4.3 AU in the present case. Only two other such events were monitored well enough to detect Neptunes, and so this detection by itself suggests that Neptune mass-ratio planets are common. Moreover, another Neptune was recently discovered at a similar distance from its parent star in a low-magnification event, which are more common but are individually much less sensitive to planets. Combining the two detections yields 90% upper and lower frequency limits f=0.37^{+0.30}_{-0.21} over just 0.4 decades of planet-star separation. In particular, f>16% at 90% confidence. The parent star hosts no Jupiter-mass companions with projected separations within a factor 5 of that of the detected planet. The lens-source relative proper motion is \\mu~7--10 mas/yr, implying that if the lens is sufficiently bright, Iplanet. Analogs of OGLE-2005-BLG-169Lb orbiting nearby stars would be difficult to detect by other methods of planet detection, including radial velocities, transits, or astrometry.

  7. SU-E-I-88: Mammography Imaging: Does Positioning Matter?

    SciTech Connect (OSTI)

    Zhang, J; Szabunio, M [University of Kentucky, Lexington, KY (United States)

    2014-06-01

    Purpose: In mammography, compression is imperative for quality images and glandular radiation exposure dose. The thickness of the compressed breast directly determines mammography acquisition parameters. The compressed thickness varies due to variation in technologist practice, even for the same patient imaged at different time. This study is to investigate potential effect of the variation in breast positioning on radiation dose and image quality. Methods: Radiation dose at different thicknesses was measured with a BR-12 breast phantom for both conventional craniocaudal view and tomosynthesis in a Hologic Tomosynthesis mammography system. The CIRS stereotactic needle biopsy training phantom embedded dense masses and microcalcification in various sizes were imaged for image quality evaluation. Radiologists evaluated images. Clinical mammograms from the same patient but acquired at different time were retrospectively retrieved to evaluate potential effects of variation in positioning. Results: Acquisition parameters (kVp and mAs) increase with the increased phantom thickness. Radiation exposure increases following an exponential trend. The stereotactic phantom images showed loss of spatial and contrast resolution with inappropriate positioning. The compressed pressure may not be a good indicator for appropriate positioning. The inclusion of different amount of pectoralis muscle may lead to the same compressed pressure but different compressed thickness. The initial retrospective study of 3 patients showed that there were potential large variations in positioning the same patient at different examination time, resulting in large variations in patient radiation dose and image quality. Conclusion: Variations in patient positioning potentially influence patient radiation dose and image quality. The technologist has the critical responsibility to position patient to provide quality images in spite of different breast and body types. To reduce intra and inter practice variations in positioning patient, a training program among each breast imaging center may be a need.

  8. Full differentiation and assignment of boron species in the electrolytes Li{sub 2}B{sub 6}O{sub 9}F{sub 2} and Li{sub 2}B{sub 3}O{sub 4}F{sub 3} by solid-state {sup 11}B NMR spectroscopy

    SciTech Connect (OSTI)

    Braeuniger, Thomas; Pilz, Thomas; Chandran, C. Vinod; Jansen, Martin

    2012-10-15

    The syntheses of two new fluorooxoborates, Li{sub 2}B{sub 3}O{sub 4}F{sub 3} and Li{sub 2}B{sub 6}O{sub 9}F{sub 2}, which possess considerable ion conductivity at higher temperatures, have been reported recently. Here, we describe the characterisation of these compounds by solid-state {sup 11}B NMR spectroscopy. The complex central-transition MAS spectra, resulting from overlap of sub-spectra contributed by the individual boron species in the crystal structures, could be clearly separated by acquisition and analysis of 3QMAS spectra. By numerical fit of these sub-spectra, the isotropic chemical shift {delta}{sub iso}, the quadrupolar coupling constant {chi}, and the asymmetry {eta} were determined. Using known relations between boron coordination and chemical shift as well as quadrupolar coupling, the individual {sup 11}B NMR resonances have been ascribed to boron species in tetrahedral or trigonal environment. To remove remaining assignment ambiguities, the response of the {sup 11}B resonances to {sup 19}F decoupling was qualitatively analysed. Thus, by using the combined information conveyed by chemical shift, quadrupolar and dipolar interaction, a complete assignment of the complex {sup 11}B line shapes exhibited by the fluorooxoborates has been achieved. - Graphical abstract: Structure and solid-state {sup 11}B NMR spectrum of Li{sub 2}B{sub 3}O{sub 4}F{sub 3}. Highlights: Black-Right-Pointing-Pointer Characterisation of title compounds by solid-state {sup 11}B NMR spectroscopy. Black-Right-Pointing-Pointer Sub-spectra of boron species separated by evaluation of 3QMAS spectra. Black-Right-Pointing-Pointer Isotropic chemical shift and quadrupolar interaction parameters determined. Black-Right-Pointing-Pointer Full boron assignment based on NMR parameters and response to {sup 19}F decoupling.

  9. TOWARD A SPECTROSCOPIC CENSUS OF WHITE DWARFS WITHIN 40 pc OF THE SUN

    SciTech Connect (OSTI)

    Limoges, M.-M.; Bergeron, P.; Lepine, S. E-mail: bergeron@astro.umontreal.ca

    2013-05-15

    We present the preliminary results of a survey aimed at significantly increasing the range and completeness of the local census of spectroscopically confirmed white dwarfs. The current census of nearby white dwarfs is reasonably complete only to about 20 pc of the Sun, a volume that includes around 130 white dwarfs, a sample too small for detailed statistical analyses. This census is largely based on follow-up investigations of stars with very large proper motions. We describe here the basis of a method that will lead to a catalog of white dwarfs within 40 pc of the Sun and north of the celestial equator, thus increasing by a factor of eight the extent of the northern sky census. White dwarf candidates are identified from the SUPERBLINK proper motion database, allowing us to investigate stars down to a proper motion limit {mu} > 40 mas yr{sup -1}, while minimizing the kinematic bias for nearby objects. The selection criteria and distance estimates are based on a combination of color-magnitude and reduced proper motion diagrams. Our follow-up spectroscopic observation campaign has so far uncovered 193 new white dwarfs, among which we identify 127 DA (including 9 DA+dM and 4 magnetic), 1 DB, 56 DC, 3 DQ, and 6 DZ stars. We perform a spectroscopic analysis on a subsample of 84 DAs, and provide their atmospheric parameters. In particular, we identify 11 new white dwarfs with spectroscopic distances within 25 pc of the Sun, including five candidates to the D < 20 pc subset.

  10. WIDE COMPANIONS TO HIPPARCOS STARS WITHIN 67 pc OF THE SUN

    SciTech Connect (OSTI)

    Tokovinin, Andrei; Lepine, Sebastien E-mail: lepine@amnh.org

    2012-10-01

    A catalog of common-proper-motion (CPM) companions to stars within 67 pc of the Sun is constructed based on the SUPERBLINK proper-motion survey. It contains 1392 CPM pairs with angular separations 30'' < {rho} < 1800'', relative proper motion between the two components less than 25 mas yr{sup -1}, and magnitudes and colors of the secondaries consistent with those of dwarfs in the (M{sub V} , V - J) diagram. In addition, we list 21 candidate white dwarf CPM companions with separations under 300'', about half of which should be physical. We estimate a 0.31 fraction of pairs with red dwarf companions to be physical systems (about 425 objects), while the rest (mostly wide pairs) are chance alignments. For each candidate companion, the probability of a physical association is evaluated. The distribution of projected separations s of the physical pairs between 2 kAU and 64 kAU follows f(s){proportional_to}s {sup -1.5}, which decreases faster than Oepik's law. We find that solar-mass dwarfs have no less than 4.4% {+-} 0.3% companions with separations larger than 2 kAU, or 3.8% {+-} 0.3% per decade of orbital separation in the 2-16 kAU range. The distribution of mass ratio of those wide companions is approximately uniform in the 0.1 < q < 1.0 range, although we observe a dip at q {approx_equal} 0.5 which, if confirmed, could be evidence of bimodal distribution of companion masses. New physical CPM companions to two exoplanet host stars are discovered.

  11. Damage Accumulation in MgAl{sub 2}O{sub 4} and Yttria-Stabilized ZrO{sub 2} by Xe-Ion Irradiation

    SciTech Connect (OSTI)

    Afanasyev-Charkin, I.V.; Gritsyna, V.T.; Cooke, D.W.; Bennett, B.L.; Sickafus, K.E.

    1999-04-25

    Magnesium-aluminate spinel (MAS) and yttria-stabilized zirconia (YSZ) are being considered for use as ceramic matrices in proliferation resistant fuels and radioactive storage systems, and may be used either as individual entities or as constituents in multicomponent ceramic systems. It is worthwhile, therefore, to compare radiation damage in these two potentially important materials when subjected to similar irradiation conditions, e.g., ion beam irradiation. To compare radiation damage properties of these two materials, single crystals of spinel and zirconia were irradiated with 340 keV Xe{sup ++} ions at 120 K, and subsequently investigated by Rutherford backscattering and ion channeling (RBS/C), and optical absorption spectroscopy. Results indicate that damage accumulation in both spinel and zirconia follow a three stage process: (1) very slow damage accumulation over a wide range of dose; (2) rapid changes in damage over a range of doses from about 0.25 to 25 displacements per atom (DPA); (3) slower damage accumulation at very high doses and possibly saturation. Optical absorption results indicate that F-centers form in Xe ion-irradiated spinel and that the concentration of these centers saturates at high dose. Absorption bands are also formed in both spinel and zirconia that are due to point defect complexes formed upon irradiation. These bands increase in intensity with increasing Xe dose, and, in the case of zirconia, without saturation. Finally the rate of change in intensity of these bands with increasing Xe dose, mimic the changes in damage observed by RBS/C with increasing dose.

  12. PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637-752

    SciTech Connect (OSTI)

    Godfrey, L. E. H.; Ekers, R.; Lovell, J. E. J.; Burke-Spolaor, S.; Bicknell, G. V.; Jauncey, D. L.; Birkinshaw, M.; Worrall, D. M.; Schwartz, D. A.; Marshall, H. L.; Gelbord, J.; Perlman, E. S.; Georganopoulos, M.

    2012-10-20

    We present 18 GHz Australia Telescope Compact Array imaging of the megaparsec-scale quasar jet PKS 0637-752 with angular resolution {approx}0.''58. We draw attention to a spectacular train of quasi-periodic knots along the inner 11'' of the jet, with average separation {approx}1.1 arcsec (7.6 kpc projected). We consider two classes of model to explain the periodic knots: those that involve a static pattern through which the jet plasma travels (e.g., stationary shocks) and those that involve modulation of the jet engine. Interpreting the knots as re-confinement shocks implies the jet kinetic power Q{sub jet} {approx} 10{sup 46} erg s{sup -1}, but the constant knot separation along the jet is not expected in a realistic external density profile. For models involving modulation of the jet engine, we find that the required modulation period is 2 Multiplication-Sign 10{sup 3} yr < {tau} < 3 Multiplication-Sign 10{sup 5} yr. The lower end of this range is applicable if the jet remains highly relativistic on kiloparsec scales, as implied by the IC/CMB model of jet X-ray emission. We suggest that the periodic jet structure in PKS 0637-752 may be analogous to the quasi-periodic jet modulation seen in the microquasar GRS 1915+105, believed to result from limit cycle behavior in an unstable accretion disk. If variations in the accretion rate are driven by a binary black hole, the predicted orbital radius is 0.7 pc {approx}< a {approx}< 30 pc, which corresponds to a maximum angular separation of {approx}0.1-5 mas.

  13. Relativistic Beaming and the Intrinsic Properties of Extragalactic Radio Jets

    E-Print Network [OSTI]

    M. H. Cohen; M. L. Lister; D. C. Homan; M. Kadler; K. I. Kellermann; Y. Y. Kovalev; R. C. Vermeulen

    2006-11-20

    Relations between the observed quantities for a beamed radio jet, apparent transverse speed and apparent luminosity (beta_app,L), and the intrinsic quantities, Lorentz factor and intrinsic luminosity (gamma,L_o), are investigated. The inversion from measured to intrinsic values is not unique, but approximate limits to gamma and L_o can be found using probability arguments. Roughly half the sources in a flux density--limited, beamed sample have a value of gamma close to the measured beta_app. The methods are applied to observations of 119 AGN jets made with the VLBA at 15 GHz during 1994-2002. The results strongly support the common relativistic beam model for an extragalactic radio jet. The (beta_app,L) data are closely bounded by a theoretical envelope, an aspect curve for gamma=32, L_o= 10^25 W/Hz. This gives limits to the maximum values of gamma and L_o in the sample: gamma_max about 32, and L_o,max ~ 10^26 W/Hz. No sources with both high beta_app and low L are observed. This is not the result of selection effects due to the observing limits, which are flux density S>0.5 Jy, and angular velocity mu<4 mas/yr. Many of the fastest quasars have a pattern Lorentz factor gamma_p close to that of the beam, gamma_b, but some of the slow quasars must have gamma_p<

  14. Cyclization phenomena in the sol-gel polymerization of {alpha},{omega}-bis(triethoxysilyl)alkanes and incorporation of the cyclic structures into network silsesquioxane polymers

    SciTech Connect (OSTI)

    Loy, D.A.; Carpenter, J.P.; Alam, T.M.; Shaltout, R. [Sandia National Labs., Albuquerque, NM (United States)] [Sandia National Labs., Albuquerque, NM (United States); Dorhout, P.K. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Chemistry] [Colorado State Univ., Fort Collins, CO (United States). Dept. of Chemistry; Greaves, J.; Shea, K.J. [Univ. of California, Irvine, CA (United States). Dept. of Chemistry] [Univ. of California, Irvine, CA (United States). Dept. of Chemistry; Small, J.H. [Los Alamos National Lab., NM (United States). Polymers and Coatings Group] [Los Alamos National Lab., NM (United States). Polymers and Coatings Group

    1999-06-16

    Intramolecular cyclizations during acid-catalyzed sol-gel polymerizations of {alpha},{omega}-bis(triethoxysilyl)alkanes substantially lengthen gel times for monomers with ethylene (1), propylene (2), and butylene (3) bridging groups. These cyclization reactions were found, using mass spectrometry and {sup 29}Si NMR spectroscopy, to lead preferentially to monomeric and dimeric products based on six- and seven-membered disilsesquioxane rings. 1,2-Bis(triethoxysilyl)ethane (1) reacts under acidic conditions to give a bicyclic dimer (5) that is composed of two annelated seven-membered rings. Under the same conditions, 1,3-bis(triethoxysilyl)propane (2), 1,4-bis(triethoxysilyl)butane (3), and Z-1,4-bis(triethoxysilyl)but-2-ene (10) undergo an intramolecular condensation reaction to give the six- and seven-membered cyclic disilsesquioxanes 6, 7, and 11. Subsequently, these cyclic monomers slowly react to form the tricyclic dimers 8, 9, and 12. With NaOH as polymerization catalyst, these cyclic silsesquioxanes readily reacted to afford gels that were shown by CP MAS {sup 29}Si NMR and infrared spectroscopies to retain some cyclic structures. Comparison of the porosity and microstructure of xerogels prepared from the cyclic monomers 6 and 7 with those of gels prepared directly from their acyclic precursors 2 and 3 indicates that the final pore structure of the xerogels is markedly dependent on the nature of the precursor. In addition, despite the fact that the monomeric cyclic disilsesquioxane species cannot be isolated from 1--3 under basic conditions due to their rapid rate of gelation, spectroscopic techniques also detected the presence of the cyclic structures in the resulting polymeric gels.

  15. Cyclization Phenomena in the Sol-Gel Polymerization of a,w-Bis(triethoxysilyl)alkanes and Incorporation of the Cyclic Structures into Network Silsesquioxane Polymers

    SciTech Connect (OSTI)

    Alam, T.M.; Carpenter, J.P.; Dorhout, P.K.; Greaves, J.; Loy, D.A.; Shaltout, R.; Shea, K.J.; Small, J.H.

    1999-01-04

    Intramolecular cyclizations during acid-catalyzed, sol-gel polymerizations of ct,co- bis(tietioxysilyl)aWmes substintidly lengtien gelties formonomers witietiylene- (l), propylene- (2), and butylene-(3)-bridging groups. These cyclizations reactions were found, using mass spectrometry and %i NMR spectroscopy, to lead preferentially to monomeric and dimeric products based on six and seven membered disilsesquioxane rings. 1,2- Bis(triethoxysilyl)ethane (1) reacts under acidic conditions to give a bicyclic drier (5) that is composed of two annelated seven membered rings. Under the same conditions, 1,3- bis(triethoxysilyl)propane (2), 1,4-bis(triethoxysilyl)butane (3), and z-1,4- bis(triethoxysilyl)but-2-ene (10) undergo an intramolecular condensation reaction to give the six membemd and seven membered cyclic disilsesquioxanes 6, 7, and 11. Subsequently, these cyclic monomers slowly react to form the tricyclic dirners 8,9 and 12. With NaOH as polymerization catalyst these cyclic silsesquioxanes readily ~aeted to afford gels that were shown by CP MAS z%i NMR and infr=d spectroscopes to retain some cyclic structures. Comparison of the porosity and microstructwe of xerogels prepared from the cyclic monomers 6 and 7 with gels prepared directly from their acyclic precursors 2 and 3, indicate that the final pore structure of the xerogels is markedly dependent on the nature of the precursor. In addition, despite the fact that the monomeric cyclic disilsesquioxane species can not be isolated from 1-3 under basic conditions due to their rapid rate of gelation, spectroscopic techniques also detected the presence of the cyclic structures in the resulting polymeric gels.

  16. Kilovoltage cone-beam CT imaging dose during breast radiotherapy: A dose comparison between a left and right breast setup

    SciTech Connect (OSTI)

    Quinn, Alexandra; Holloway, Lois; Begg, Jarrad; Nelson, Vinod; Metcalfe, Peter

    2014-07-01

    The purpose of this study was to investigate the delivered dose from a kilovoltage cone-beam computed tomography (kV-CBCT) acquired in breast treatment position for a left and right breast setup. The dose was measured with thermoluminescent dosimeters positioned within a female anthropomorphic phantom at organ locations. Imaging was performed on an Elekta Synergy XVI system with the phantom setup on a breast board. The image protocol involved 120 kVp, 140 mAs, and a 270° arc rotation clockwise 0° to 270° for the left breast setup and 270° to 180° for the right breast setup (maximum arc rotations possible). The dose delivered to the left breast, right breast, and heart was 5.1 mGy, 3.9 mGy, and 4.0 mGy for the left breast setup kV-CBCT, and 6.4 mGy, 6.0 mGy, and 4.8 mGy for the right breast setup kV-CBCT, respectively. The rotation arc of the kV-CBCT influenced the dose delivered, with the right breast setup kV-CBCT found to deliver a dose of up to 4 mGy or 105% higher to the treated breast?s surface in comparison with the left breast setup. This is attributed to the kV-CBCT source being more proximal to the anterior of the phantom for a right breast setup, whereas the source is more proximal to the posterior of the patient for a left-side scan.

  17. Searching for circumplanetary disks around LkCa 15

    SciTech Connect (OSTI)

    Isella, Andrea; Carpenter, John M.; Ricci, Luca [Department of Astronomy, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Chandler, Claire J.; Pérez, Laura M., E-mail: isella@astro.caltech.edu [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States)

    2014-06-20

    We present Karl G. Jansky Very Large Array (VLA) observations of the 7 mm continuum emission from the disk surrounding the young star LkCa 15. The observations achieve an angular resolution of 70 mas and spatially resolve the circumstellar emission on a spatial scale of 9 AU. The continuum emission traces a dusty annulus of 45 AU in radius that is consistent with the dust morphology observed at shorter wavelengths. The VLA observations also reveal a compact source at the center of the disk, possibly due to thermal emission from hot dust or ionized gas located within a few AU from the central star. No emission is observed between the star and the dusty ring and, in particular, at the position of the candidate protoplanet LkCa 15 b. By comparing the observations with theoretical models for circumplanetary disk emission, we find that if LkCa 15 b is a massive planet (>5 M{sub J} ) accreting at a rate greater than 10{sup –6} M{sub J} yr{sup –1}, then its circumplanetary disk is less massive than 0.1 M{sub J} , or smaller than 0.4 Hill radii. Similar constraints are derived for any possible circumplanetary disk orbiting within 45 AU from the central star. The mass estimates are uncertain by at least one order of magnitude due to the uncertainties on the mass opacity. Future ALMA observations of this system might be able to detect circumplanetary disks down to a mass of 5 × 10{sup –4} M{sub J} and as small as 0.2 AU, providing crucial constraints on the presence of giant planets in the act of forming around this young star.

  18. PROPER-MOTION STUDY OF THE MAGELLANIC CLOUDS USING SPM MATERIAL

    SciTech Connect (OSTI)

    Vieira, Katherine; Girard, Terrence M.; Van Altena, William F.; Casetti-Dinescu, Dana I.; Korchagin, Vladimir I.; Herrera, David, E-mail: kvieira@cida.v, E-mail: terry.girard@yale.ed, E-mail: william.vanaltena@yale.ed [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)

    2010-12-15

    Absolute proper motions are determined for stars and galaxies to V = 17.5 over a 450 deg{sup 2} area that encloses both Magellanic Clouds. The proper motions are based on photographic and CCD observations of the Yale/San Juan Southern Proper Motion program, which span a baseline of 40 years. Multiple, local relative proper-motion measures are combined in an overlap solution using photometrically selected Galactic disk stars to define a global relative system that is then transformed to absolute using external galaxies and Hipparcos stars to tie into the ICRS. The resulting catalog of 1.4 million objects is used to derive the mean absolute proper motions of the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC); ({mu}{sub {alpha}}cos {delta}, {mu}{sub {delta}}){sub LMC} = (1.89, + 0.39) {+-} (0.27, 0.27) masyr{sup -1} and ({mu}{sub {alpha}}cos {delta}, {mu}{sub {delta}}){sub SMC} = (0.98, - 1.01) {+-} (0.30, 0.29) masyr{sup -1}. These mean motions are based on best-measured samples of 3822 LMC stars and 964 SMC stars. A dominant portion (0.25 mas yr{sup -1}) of the formal errors is due to the estimated uncertainty in the inertial system of the Hipparcos Catalog stars used to anchor the bright end of our proper motion measures. A more precise determination can be made for the proper motion of the SMC relative to the LMC; ({mu}{sub {alpha}cos {delta}}, {mu}{sub {delta}}){sub SMC-LMC} = (-0.91, - 1.49) {+-} (0.16, 0.15) masyr{sup -1}. This differential value is combined with measurements of the proper motion of the LMC taken from the literature to produce new absolute proper-motion determinations for the SMC, as well as an estimate of the total velocity difference of the two clouds to within {+-}54 km s{sup -1}. The absolute proper-motion results are consistent with the Clouds' orbits being marginally bound to the Milky Way, albeit on an elongated orbit. The inferred relative velocity between the Clouds places them near their binding energy limit and, thus, no definitive conclusion can be made as to whether or not the Clouds are bound to one another.

  19. Cs{sub 4}P{sub 2}Se{sub 10}: A new compound discovered with the application of solid-state and high temperature NMR

    SciTech Connect (OSTI)

    Gave, Matthew A.; Canlas, Christian G. [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Chung, In [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States); Iyer, Ratnasabapathy G. [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Kanatzidis, Mercouri G. [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States)], E-mail: m-kanatzidis@northwestern.edu; Weliky, David P. [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States)], E-mail: weliky@chemistry.msu.edu

    2007-10-15

    The new compound Cs{sub 4}P{sub 2}Se{sub 10} was serendipitously produced in high purity during a high-temperature synthesis done in a nuclear magnetic resonance (NMR) spectrometer. {sup 31}P magic angle spinning (MAS) NMR of the products of the synthesis revealed that the dominant phosphorus-containing product had a chemical shift of -52.8 ppm that could not be assigned to any known compound. Deep reddish brown well-formed plate-like crystals were isolated from the NMR reaction ampoule and the structure was solved with X-ray diffraction. Cs{sub 4}P{sub 2}Se{sub 10} has the triclinic space group P-1 with a=7.3587(11) A, b=7.4546(11) A, c=10.1420(15) A, {alpha}=85.938(2){sup o}, {beta}=88.055(2){sup o}, and {gamma}=85.609(2){sup o} and contains the [P{sub 2}Se{sub 10}]{sup 4-} anion. To our knowledge, this is the first compound containing this anion that is composed of two tetrahedral (PSe{sub 4}) units connected by a diselenide linkage. It was also possible to form a glass by quenching the melt in ice water, and Cs{sub 4}P{sub 2}Se{sub 10} was recovered upon annealing. The static {sup 31}P NMR spectrum at 350 deg. C contained a single peak with a -35 ppm chemical shift and a {approx}7 ppm peak width. This study highlights the potential of solid-state and high-temperature NMR for aiding discovery of new compounds and for probing the species that exist at high temperature. - Graphical abstract: The new compound Cs{sub 4}P{sub 2}Se{sub 10} was discovered following a high-temperature in situ synthesis in the NMR spectrometer and the structure was determined by single-crystal X-ray diffraction. It contains the new [P{sub 2}Se{sub 10}]{sup 4-} anion.

  20. Dose equations for shift-variant CT acquisition modes using variable pitch, tube current, and aperture, and the meaning of their associated CTDI{sub vol}

    SciTech Connect (OSTI)

    Dixon, Robert L.; Boone, John M.; Kraft, Robert A.

    2014-11-01

    Purpose: With the increasing clinical use of shift-variant CT protocols involving tube current modulation (TCM), variable pitch or pitch modulation (PM), and variable aperture a(t), the interpretation of the scanner-reported CTDI{sub vol} is called into question. This was addressed for TCM in their previous paper published by Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)] and is extended to PM and concurrent TCM/PM as well as variable aperture in this work. Methods: Rigorous convolution equations are derived to describe the accumulated dose distributions for TCM, PM, and concurrent TCM/PM. A comparison with scanner-reported CTDI{sub vol} formulae clearly identifies the source of their differences with the traditional CTDI{sub vol}. Dose distribution simulations using the convolution are provided for a variety of TCM and PM scenarios including a helical shuttle used for perfusion studies (as well as constant mA)—all having the same scanner-reported CTDI{sub vol}. These new convolution simulations for TCM are validated by comparison with their previous discrete summations. Results: These equations show that PM is equivalent to TCM if the pitch variation p(z) is proportional to 1/i(z), where i(z) is the local tube current. The simulations show that the local dose at z depends only weakly on the local tube current i(z) or local pitch p(z) due to scatter from all other locations along z, and that the “local CTDI{sub vol}(z)” or “CTDI{sub vol} per slice” do not represent a local dose but rather only a relative i(z) or p(z). The CTDI-paradigm does not apply to shift-variant techniques and the scanner-reported CTDI{sub vol} for the same lacks physical significance and relevance. Conclusions: While the traditional CTDI{sub vol} at constant tube current and pitch conveys useful information (the peak dose at the center of the scan length), CTDI{sub vol} for shift-variant techniques (TCM or PM) conveys no useful information about the associated dose distribution it purportedly represents. On the other hand, the total energy absorbed E (“integral dose”) as well as its surrogate DLP remain robust (invariant) with respect to shift-variance, depending only on the total mAs = ?i?t{sub 0} accumulated during the total beam-on time t{sub 0} and aperture a, where ?i? is the average current.

  1. THE M31 VELOCITY VECTOR. I. HUBBLE SPACE TELESCOPE PROPER-MOTION MEASUREMENTS

    SciTech Connect (OSTI)

    Sohn, Sangmo Tony; Anderson, Jay; Van der Marel, Roeland P.

    2012-07-01

    We present the first proper-motion (PM) measurements for the galaxy M31. We obtained new V-band imaging data with the Hubble Space Telescope ACS/WFC and the WFC3/UVIS instruments of three fields: a spheroid field near the minor axis, an outer disk field along the major axis, and a field on the Giant Southern Stream. The data provide five to seven year time baselines with respect to pre-existing deep first-epoch observations of the same fields. We measure the positions of thousands of M31 stars and hundreds of compact background galaxies in each field. High accuracy and robustness is achieved by building and fitting a unique template for each individual object. The average PM for each field is obtained from the average motion of the M31 stars between the epochs with respect to the background galaxies. For the three fields, the observed PMs ({mu}{sub W}, {mu}{sub N}) are, in units of mas yr{sup -1}, (- 0.0458, -0.0376) {+-} (0.0165, 0.0154), (- 0.0533, -0.0104) {+-} (0.0246, 0.0244), and (- 0.0179, -0.0357) {+-} (0.0278, 0.0272), respectively. The ability to average over large numbers of objects and over the three fields yields a final displacement accuracy of a few thousandths of a pixel, corresponding to only 12 {mu}as yr{sup -1}. This is comparable to what has been achieved for other Local Group galaxies using Very Long Baseline Array observations of water masers. Potential systematic errors are controlled by an analysis strategy that corrects for detector charge transfer inefficiency, spatially and time-dependent geometric distortion, and point-spread function variations. The robustness of the PM measurements and uncertainties are supported by the fact that data from different instruments, taken at different times and with different telescope orientations, as well as measurements of different fields, all yield statistically consistent results. Papers II and III of this series explore the implications of the new measurements for our understanding of the history, future, and mass of the Local Group.

  2. SU-D-9A-07: Imaging Dose and Cancer Risk in Image-Guided Radiotherapy of Cancers

    SciTech Connect (OSTI)

    Zhou, L; Bai, S; Zhang, Y; Ming, X; Zhang, Y; Deng, J

    2014-06-01

    Purpose: To systematically evaluate the imaging doses and cancer risks associated with various imaging procedures involving ionizing radiation during image-guided radiotherapy of an increasingly large number of cancer patients. Methods: 141 patients (52 brain cases, 47 thoracic cases, 42 abdominal cases, aged 3 to 91 years old) treated between October 2009 and March 2010 were included in this IRB-approved retrospective study. During the whole radiotherapy course, each patient underwent at least one type of imaging procedures, i.e., kV portal, MV portal and kVCBCT, besides CT simulations. Based on Monte Carlo modeling and particle transport in human anatomy of various dimensions, the correlations between the radiation doses to the various organs-at-risk (OARs) at the head, the thoracic and the abdominal regions and one's weight, circumference, scan mAs and kVp have been obtained and used to estimate the radiation dose from a specific imaging procedure. The radiation-induced excess relative risk (ERR) was then estimated with BEIR VII formulism based on one's gender, age and radiation dose. 1+ ERR was reported in this study as relative cancer risk. Results: For the whole cohort of 141 patients, the mean imaging doses from various imaging procedures were 8.3 cGy to the brain, 10.5 cGy to the lungs and 19.2 cGy to the red bone marrow, respectively. Accordingly, the cancer risks were 1.140, 1.369 and 2.671, respectively. In comparison, MV portal deposited largest doses to the lungs while kVCBCT delivered the highest doses to the red bone marrow. Conclusion: The compiled imaging doses to a patient during his/her treatment course were patient-specific and site-dependent, varying from 1.2 to 263.5 cGy on average, which were clinically significant and should be included in the treatment planning and overall decision-making. Our results indicated the necessity of personalized imaging to maximize its clinical benefits while reducing the associated cancer risks. Sichuan University Scholarship.

  3. Noise correlation in CBCT projection data and its application for noise reduction in low-dose CBCT

    SciTech Connect (OSTI)

    Zhang, Hua; Ouyang, Luo; Wang, Jing E-mail: jing.wang@utsouthwestern.edu; Ma, Jianhua E-mail: jing.wang@utsouthwestern.edu; Huang, Jing; Chen, Wufan

    2014-03-15

    Purpose: To study the noise correlation properties of cone-beam CT (CBCT) projection data and to incorporate the noise correlation information to a statistics-based projection restoration algorithm for noise reduction in low-dose CBCT. Methods: In this study, the authors systematically investigated the noise correlation properties among detector bins of CBCT projection data by analyzing repeated projection measurements. The measurements were performed on a TrueBeam onboard CBCT imaging system with a 4030CB flat panel detector. An anthropomorphic male pelvis phantom was used to acquire 500 repeated projection data at six different dose levels from 0.1 to 1.6 mAs per projection at three fixed angles. To minimize the influence of the lag effect, lag correction was performed on the consecutively acquired projection data. The noise correlation coefficient between detector bin pairs was calculated from the corrected projection data. The noise correlation among CBCT projection data was then incorporated into the covariance matrix of the penalized weighted least-squares (PWLS) criterion for noise reduction of low-dose CBCT. Results: The analyses of the repeated measurements show that noise correlation coefficients are nonzero between the nearest neighboring bins of CBCT projection data. The average noise correlation coefficients for the first- and second-order neighbors are 0.20 and 0.06, respectively. The noise correlation coefficients are independent of the dose level. Reconstruction of the pelvis phantom shows that the PWLS criterion with consideration of noise correlation (PWLS-Cor) results in a lower noise level as compared to the PWLS criterion without considering the noise correlation (PWLS-Dia) at the matched resolution. At the 2.0 mm resolution level in the axial-plane noise resolution tradeoff analysis, the noise level of the PWLS-Cor reconstruction is 6.3% lower than that of the PWLS-Dia reconstruction. Conclusions: Noise is correlated among nearest neighboring detector bins of CBCT projection data. An accurate noise model of CBCT projection data can improve the performance of the statistics-based projection restoration algorithm for low-dose CBCT.

  4. Implications of CT noise and artifacts for quantitative {sup 99m}Tc SPECT/CT imaging

    SciTech Connect (OSTI)

    Hulme, K. W.; Kappadath, S. C.

    2014-04-15

    Purpose: This paper evaluates the effects of computed tomography (CT) image noise and artifacts on quantitative single-photon emission computed-tomography (SPECT) imaging, with the aim of establishing an appropriate range of CT acquisition parameters for low-dose protocols with respect to accurate SPECT attenuation correction (AC). Methods: SPECT images of two geometric and one anthropomorphic phantom were reconstructed iteratively using CT scans acquired at a range of dose levels (CTDI{sub vol} = 0.4 to 46 mGy). Resultant SPECT image quality was evaluated by comparing mean signal, background noise, and artifacts to SPECT images reconstructed using the highest dose CT for AC. Noise injection was performed on linear-attenuation (?) maps to determine the CT noise threshold for accurate AC. Results: High levels of CT noise (? ? 200–400 HU) resulted in low ?-maps noise (? ? 1%–3%). Noise levels greater than ?10% in 140 keV ?-maps were required to produce visibly perceptible increases of ?15% in {sup 99m}Tc SPECT images. These noise levels would be achieved at low CT dose levels (CTDI{sub vol} = 4 ?Gy) that are over 2 orders of magnitude lower than the minimum dose for diagnostic CT scanners. CT noise could also lower (bias) the expected ? values. The relative error in reconstructed SPECT signal trended linearly with the relative shift in ?. SPECT signal was, on average, underestimated in regions corresponding with beam-hardening artifacts in CT images. Any process that has the potential to change the CT number of a region by ?100 HU (e.g., misregistration between CT images and SPECT images due to motion, the presence of contrast in CT images) could introduce errors in ?{sub 140} {sub keV} on the order of 10%, that in turn, could introduce errors on the order of ?10% into the reconstructed {sup 99m}Tc SPECT image. Conclusions: The impact of CT noise on SPECT noise was demonstrated to be negligible for clinically achievable CT parameters. Because CT dose levels that affect SPECT quantification is low (CTDI{sub vol} ? 4 ?Gy), the low dose limit for the CT exam as part of SPECT/CT will be guided by CT image quality requirements for anatomical localization and artifact reduction. A CT technique with higher kVp in combination with lower mAs is recommended when low-dose CT images are used for AC to minimize beam-hardening artifacts.

  5. Dose equations for tube current modulation in CT scanning and the interpretation of the associated CTDI{sub vol}

    SciTech Connect (OSTI)

    Dixon, Robert L. [Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157 (United States)] [Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157 (United States); Boone, John M. [Department of Radiology and Department of Biomedical Engineering, University of California Davis, Sacramento, California 95817 (United States)] [Department of Radiology and Department of Biomedical Engineering, University of California Davis, Sacramento, California 95817 (United States)

    2013-11-15

    Purpose: The scanner-reported CTDI{sub vol} for automatic tube current modulation (TCM) has a different physical meaning from the traditional CTDI{sub vol} at constant mA, resulting in the dichotomy “CTDI{sub vol} of the first and second kinds” for which a physical interpretation is sought in hopes of establishing some commonality between the two.Methods: Rigorous equations are derived to describe the accumulated dose distributions for TCM. A comparison with formulae for scanner-reported CTDI{sub vol} clearly identifies the source of their differences. Graphical dose simulations are also provided for a variety of TCM tube current distributions (including constant mA), all having the same scanner-reported CTDI{sub vol}.Results: These convolution equations and simulations show that the local dose at z depends only weakly on the local tube current i(z) due to the strong influence of scatter from all other locations along z, and that the “local CTDI{sub vol}(z)” does not represent a local dose but rather only a relative i(z) ? mA(z). TCM is a shift-variant technique to which the CTDI-paradigm does not apply and its application to TCM leads to a CTDI{sub vol} of the second kind which lacks relevance.Conclusions: While the traditional CTDI{sub vol} at constant mA conveys useful information (the peak dose at the center of the scan length), CTDI{sub vol} of the second kind conveys no useful information about the associated TCM dose distribution it purportedly represents and its physical interpretation remains elusive. On the other hand, the total energy absorbed E (“integral dose”) as well as its surrogate DLP remain robust between variable i(z) TCM and constant current i{sub 0} techniques, both depending only on the total mAs =t{sub 0}=i{sub 0} t{sub 0} during the beam-on time t{sub 0}.

  6. SU-E-I-92: Is Photon Starvation Preventing Metal Artifact Reduction Algorithm From Working in KVCT?

    SciTech Connect (OSTI)

    Paudel, M; MacKenzie, M; Fallone, B; Rathee, S

    2014-06-01

    Purpose: High density/high atomic number metallic objects create shading and streaking metal artifacts in the CT image that can cause inaccurate delineation of anatomical structures or inaccurate radiation dose calculation. A modified iterative maximum-likelihood polychromatic algorithm for CT (mIMPACT) that models the energy response of detectors, photon interaction processes and beam polychromaticity has successfully reduced metal artifacts in MVCT. Our extension of mIMPACT in kVCT did not significantly reduce metal artifacts for high density metal like steel. We hypothesize that photon starvation may result in the measured data in a commercial kVCT imaging beam. Methods: We measured attenuation of a range of steel plate thicknesses, sandwiched between two 12cm thick solid water blocks, using a Phillips Big Bore CTTM scanner in scout acquisition mode with 120kVp and 200mAs. The transmitted signal (y) was normalized to the air scan signal (y{sub 0}) to get attenuation [i.e., ln(y/y{sub 0})] data for a detector. Results: Below steel plate thickness of 13.4mm, the variations in measured attenuation as a function of view number are characterized by a quantum noise and show increased attenuation with metal thickness. On or above this thickness the attenuation shows discrete levels in addition to the quantum noise. Some views have saturated attenuation value. The histograms of the measured attenuation for up to 36.7mm of steel show this trend. The detector signal is so small that the quantization levels in the analog to digital (A-to-D) converter are visible, a clear indication of photon starvation. Conclusion: Photons reaching the kVCT detector after passing through a thick metal plate are either so low in number that the signal measured has large quantum noise, or are completely absorbed inside the plate creating photon starvation. This is un-interpretable by the mIMPACT algorithm and cannot reduce metal artifacts in kVCT for certain realistic thicknesses of steel hip implants. Moti Raj Paudel is supported by the Vanier Canada Graduate Scholarship, the Endowed Graduate Scholarship in Oncology and the Dissertation Fellowship at the University of Alberta. The authors acknowledge the CIHR operating grant number MOP 53254.

  7. Molecular Siganture and Sources of Biochemical Recalcitrance of Organic C in Amozonian Dark Earths

    SciTech Connect (OSTI)

    Solomon,D.; Lehmann, J.; Thies, J.; Schafer, T.; Liang, B.; Kinyangi, J.; Neves, E.; Peterson, J.; Liuzao, F.; Skjemstad, J.

    2007-01-01

    Amazonian Dark Earths (ADE) are a unique type of soils developed through intense anthropogenic activities that transformed the original soils into Anthrosols throughout the Brazilian Amazon Basin. We conducted a comparative molecular-level investigation of soil organic C (SOC) speciation in ADE (ages between 600 and 8700 years B.P.) and adjacent soils using ultraviolet photo-oxidation coupled with {sup 13}C cross polarization-magic angle spinning nuclear magnetic resonance (CP-MAS NMR), synchrotron-based Fourier transform infrared-attenuated total reflectance (Sr-FTIR-ATR) and C (1s) near edge X-ray absorption fine structure (NEXAFS) spectroscopy to obtain deeper insights into the structural chemistry and sources of refractory organic C compounds in ADE. Our results show that the functional group chemistry of SOC in ADE was considerably different from adjacent soils. The SOC in ADE was enriched with: (i) aromatic-C structures mostly from H- and C-substituted aryl-C, (ii) O-rich organic C forms from carboxylic-C, aldehyde-C, ketonic-C and quinine-C, and (iii) diverse group of refractory aliphatic-C moieties. The SOC in adjacent soils was predominantly composed of O-alkyl-C and methoxyl-C/N-alkyl-C structures and elements of labile aliphatic-C functionalities. Our study suggests that the inherent molecular structures of organic C due to selective accumulation of highly refractory aryl-C structures seems to be the key factor for the biochemical recalcitrance and stability of SOC in ADE. Anthropogenic enrichment with charred carbonaceous residues from biomass-derived black C (BC) is presumed to be the precursor of these recalcitrant polyaromatic structures. Our results also highlight the complementary role that might be played by organic C compounds composed of O-containing organic C moieties and aliphatic-C structures that persisted for millennia in these anthropic soils as additional or secondary sources of chemical recalcitrance of SOC in ADE. These organic C compounds could be the products of: (i) primary recalcitrant biomolecules from non-BC sources or (ii) secondary processes involving microbial mediated oxidative or extracellular neoformation reactions of SOC from BC and non-BC sources; and stabilized through physical inaccessibility to decomposers due to sorption onto the surface or into porous structures of BC particles, selective preservation or through intermolecular interactions involving clay and BC particles.

  8. MOA-2011-BLG-262Lb: A sub-Earth-mass moon orbiting a gas giant primary or a high velocity planetary system in the galactic Bulge

    SciTech Connect (OSTI)

    Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Batista, V. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Bond, I. A.; Ling, C. H. [Institute of Natural and Mathematical Sciences, Massey University, Auckland 0745 (New Zealand); Bennett, C. S. [Department of Physics, Massachussets Institute of Technology, Cambridge, MA 02139 (United States); Suzuki, D.; Koshimoto, N. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Beaulieu, J.-P. [UPMC-CNRS, UMR 7095, Institut d'Astrophysique de Paris, 98bis Boulevard Arago, F-75014 Paris (France); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Donatowicz, J. [Technische Universität Wien, Wieder Hauptst. 8-10, A-1040 Vienna (Austria); Bozza, V. [Dipartimento di Fisica, Università di Salerno, Via Ponte Don Melillo 132, I-84084 Fisciano (Italy); Abe, F.; Fukunaga, D.; Itow, Y.; Masuda, K.; Matsubara, Y.; Muraki, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Botzler, C. S.; Freeman, M. [Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001 (New Zealand); Fukui, A., E-mail: bennett@nd.edu [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Okayama 719-0232 (Japan); Collaboration: MOA Collaboration; PLANET Collaboration; ?FUN Collaboration; OGLE Collaboration; RoboNet Collaboration; and others

    2014-04-20

    We present the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of M {sub host} ? 4 Jupiter masses hosting a sub-Earth mass moon. The argument for an exomoon hinges on the system being relatively close to the Sun. The data constrain the product M{sub L} ?{sub rel} where M{sub L} is the lens system mass and ?{sub rel} is the lens-source relative parallax. If the lens system is nearby (large ?{sub rel}), then M{sub L} is small (a few Jupiter masses) and the companion is a sub-Earth-mass exomoon. The best-fit solution has a large lens-source relative proper motion, ?{sub rel} = 19.6 ± 1.6 mas yr{sup –1}, which would rule out a distant lens system unless the source star has an unusually high proper motion. However, data from the OGLE collaboration nearly rule out a high source proper motion, so the exoplanet+exomoon model is the favored interpretation for the best fit model. However, there is an alternate solution that has a lower proper motion and fits the data almost as well. This solution is compatible with a distant (so stellar) host. A Bayesian analysis does not favor the exoplanet+exomoon interpretation, so Occam's razor favors a lens system in the bulge with host and companion masses of M{sub host}=0.12{sub ?0.06}{sup +0.19} M{sub ?} and m{sub comp}=18{sub ?10}{sup +28} M{sub ?}, at a projected separation of a{sub ?}=0.84{sub ?0.14}{sup +0.25} AU. The existence of this degeneracy is an unlucky accident, so current microlensing experiments are in principle sensitive to exomoons. In some circumstances, it will be possible to definitively establish the mass of such lens systems through the microlensing parallax effect. Future experiments will be sensitive to less extreme exomoons.

  9. The Milky Way Tomography with SDSS. 2. Stellar Metallicity

    SciTech Connect (OSTI)

    Ivezic, Zeljko; Sesar, Branimir; Juric, Mario; Bond, Nicholas; Dalcanton, Julianne; Rockosi, Constance M.; Yanny, Brian; Newberg, Heidi J.; Beers, Timothy C.; Prieto, Carlos Allende; Wilhelm, Ron; /Texas Tech. /Michigan State U.

    2008-04-01

    In addition to optical photometry of unprecedented quality, the Sloan Digital Sky Survey (SDSS) is producing a massive spectroscopic database which already contains over 280,000 stellar spectra. Using effective temperature and metallicity derived from SDSS spectra for {approx}60,000 F and G type main sequence stars (0.2 < g-r < 0.6), we develop polynomial models, reminiscent of traditional methods based on the UBV photometry, for estimating these parameters from the SDSS u-g and g-r colors. These estimators reproduce SDSS spectroscopic parameters with a root-mean-square scatter of 100 K for effective temperature, and 0.2 dex for metallicity (limited by photometric errors), which are similar to random and systematic uncertainties in spectroscopic determinations. We apply this method to a photometric catalog of coadded SDSS observations and study the photometric metallicity distribution of {approx}200,000 F and G type stars observed in 300 deg{sup 2} of high Galactic latitude sky. These deeper (g < 20.5) and photometrically precise ({approx}0.01 mag) coadded data enable an accurate measurement of the unbiased metallicity distribution for a complete volume-limited sample of stars at distances between 500 pc and 8 kpc. The metallicity distribution can be exquisitely modeled using two components with a spatially varying number ratio, that correspond to disk and halo. The best-fit number ratio of the two components is consistent with that implied by the decomposition of stellar counts profiles into exponential disk and power-law halo components by Juric et al. (2008). The two components also possess the kinematics expected for disk and halo stars. The metallicity of the halo component can be modeled as a spatially invariant Gaussian distribution with a mean of [Fe/H] = -1.46 and a standard deviation of {approx}0.3 dex. The disk metallicity distribution is non-Gaussian, with a remarkably small scatter (rms {approx}0.16 dex) and the median smoothly decreasing with distance from the plane from -0.6 at 500 pc to -0.8 beyond several kpc. Similarly, we find using proper motion measurements that a non-Gaussian rotational velocity distribution of disk stars shifts by {approx}50 km/s as the distance from the plane increases from 500 pc to several kpc. Despite this similarity, the metallicity and rotational velocity distributions of disk stars are not correlated (Kendall's {tau} = 0.017 {+-} 0.018). This absence of a correlation between metallicity and kinematics for disk stars is in a conflict with the traditional decomposition in terms of thin and thick disks, which predicts a strong correlation ({tau} = ?0.30 {+-} 0.04) at {approx}1 kpc from the mid-plane. Instead, the variation of the metallicity and rotational velocity distributions can be modeled using non-Gaussian functions that retain their shapes and only shift as the distance from the mid-plane increases. We also study the metallicity distribution using a shallower (g < 19.5) but much larger sample of close to three million stars in 8500 sq. deg. of sky included in SDSS Data Release 6. The large sky coverage enables the detection of coherent substructures in the kinematics-metallicity space, such as the Monoceros stream, which rotates faster than the LSR, and has a median metallicity of [Fe/H] = ?0.95, with an rms scatter of only {approx}0.15 dex. We extrapolate our results to the performance expected from the Large Synoptic Survey Telescope (LSST) and estimate that the LSST will obtain metallicity measurements accurate to 0.2 dex or better, with proper motion measurements accurate to {approx}0.2-0.5 mas/yr, for about 200 million F/G dwarf stars within a distance limit of {approx}100 kpc (g < 23.5).

  10. NbF{sub 5} and TaF{sub 5}: Assignment of {sup 19}F NMR resonances and chemical bond analysis from GIPAW calculations

    SciTech Connect (OSTI)

    Biswal, Mamata; Body, Monique; Legein, Christophe; Sadoc, Aymeric; Boucher, Florent

    2013-11-15

    The {sup 19}F isotropic chemical shifts (?{sub iso}) of two isomorphic compounds, NbF{sub 5} and TaF{sub 5}, which involve six nonequivalent fluorine sites, have been experimentally determined from the reconstruction of 1D {sup 19}F MAS NMR spectra. In parallel, the corresponding {sup 19}F chemical shielding tensors have been calculated using the GIPAW method for both experimental and DFT-optimized structures. Furthermore, the [M{sub 4}F{sub 20}] units of NbF{sub 5} and TaF{sub 5} being held together by van der Waals interactions, the relevance of Grimme corrections to the DFT optimization processes has been evaluated. However, the semi-empirical dispersion correction term introduced by such a method does not show any significant improvement. Nonetheless, a complete and convincing assignment of the {sup 19}F NMR lines of NbF{sub 5} and TaF{sub 5} is obtained, ensured by the linearity between experimental {sup 19}F ?{sub iso} values and calculated {sup 19}F isotropic chemical shielding ?{sub iso} values. The effects of the geometry optimizations have been carefully analyzed, confirming among other matters, the inaccuracy of the experimental structure of NbF{sub 5}. The relationships between the fluorine chemical shifts, the nature of the fluorine atoms (bridging or terminal), the position of the terminal ones (opposite or perpendicular to the bridging ones), the fluorine charges, the ionicity and the length of the M–F bonds have been established. Additionally, for three of the {sup 19}F NMR lines of NbF{sub 5}, distorted multiplets, arising from {sup 1}J-coupling and residual dipolar coupling between the {sup 19}F and {sup 93}Nb nuclei, were simulated yielding to values of {sup 93}Nb–{sup 19}F {sup 1}J-coupling for the corresponding fluorine sites. - Graphical abstract: The complete assignment of the {sup 19}F NMR lines of NbF{sub 5} and TaF{sub 5} allow establishing relationships between the {sup 19}F ?{sub iso} values, the nature of the fluorine atoms (bridging or terminal), the position of the terminal ones (opposite or perpendicular to the bridging ones), the fluorine charges, the ionicity and the length of the M–F bonds. Display Omitted - Highlights: • The {sup 19}F ?{sub iso} values of NbF{sub 5} and TaF{sub 5} have been determined. • The {sup 19}F chemical shielding tensors have been calculated using the GIPAW method. • A confident assignment of the {sup 19}F NMR lines of NbF{sub 5} and TaF{sub 5} is obtained. • The relationships between the {sup 19}F?{sub iso} values and the M–F bonds features are established.

  11. PROPER MOTIONS OF THE ARCHES CLUSTER WITH KECK LASER GUIDE STAR ADAPTIVE OPTICS: THE FIRST KINEMATIC MASS MEASUREMENT OF THE ARCHES

    SciTech Connect (OSTI)

    Clarkson, W. I. [Division of Astronomy and Astrophysics, University of California, Los Angeles, Physics and Astronomy Building, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547 (United States); Ghez, A. M.; Morris, M. R.; Yelda, S. [Department of Astronomy, Indiana University, Bloomington, 727 East 3rd Street, Swain West 319, Bloomington, IN 47405-7105 (United States); Lu, J. R. [Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822-1839 (United States); Stolte, A. [Argelander Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, 53121 Bonn (Germany); McCrady, N. [Department of Physics and Astronomy, University of Montana, 32 Campus Drive, No. 1080, Missoula, MT 59812 (United States); Do, T., E-mail: wiclarks@indiana.edu [Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697-4575 (United States)

    2012-06-01

    We report the first detection of the intrinsic velocity dispersion of the Arches cluster-a young ({approx}2 Myr), massive (10{sup 4} M{sub Sun }) starburst cluster located only 26 pc in projection from the Galactic center. This was accomplished using proper motion measurements within the central 10'' Multiplication-Sign 10'' of the cluster, obtained with the laser guide star adaptive optics system at Keck Observatory over a three-year time baseline (2006-2009). This uniform data set results in proper motion measurements that are improved by a factor {approx}5 over previous measurements from heterogeneous instruments. By careful, simultaneous accounting of the cluster and field contaminant distributions as well as the possible sources of measurement uncertainties, we estimate the internal velocity dispersion to be 0.15 {+-} 0.01 mas yr{sup -1}, which corresponds to 5.4 {+-} 0.4 km s{sup -1} at a distance of 8.4 kpc. Projecting a simple model for the cluster onto the sky to compare with our proper motion data set, in conjunction with surface density data, we estimate the total present-day mass of the cluster to be M(r < 1.0 pc) = 1.5{sup +0.74}{sub -0.60} Multiplication-Sign 10{sup 4} M{sub Sun }. The mass in stars observed within a cylinder of radius R (for comparison to photometric estimates) is found to be M(R < 0.4 pc) = 0.90{sup +0.40}{sub -0.35} Multiplication-Sign 10{sup 4} M{sub Sun} at formal 3{sigma} confidence. This mass measurement is free from assumptions about the mass function of the cluster, and thus may be used to check mass estimates from photometry and simulation. Photometric mass estimates assuming an initially Salpeter mass function ({Gamma}{sub 0} = 1.35, or {Gamma} {approx} 1.0 at present, where dN/d(log M){proportional_to}M{sup {Gamma}}) suggest a total cluster mass M{sub cl} {approx} (4-6) Multiplication-Sign 10{sup 4} M{sub Sun} and projected mass ({approx} 2 {<=} M(R < 0.4 pc) {<=} 3) Multiplication-Sign 10{sup 4} M{sub Sun }. Photometric mass estimates assuming a globally top-heavy or strongly truncated present-day mass function (PDMF; with {Gamma} {approx} 0.6) yield mass estimates closer to M(R < 0.4 pc) {approx} 1-1.2 Multiplication-Sign 10{sup 4} M{sub Sun }. Consequently, our results support a PDMF that is either top-heavy or truncated at low mass, or both. Collateral benefits of our data and analysis include: (1) cluster membership probabilities, which may be used to extract a clean-cluster sample for future photometric work; (2) a refined estimate of the bulk motion of the Arches cluster with respect to the field, which we find to be 172 {+-} 15 km s{sup -1}, which is slightly slower than suggested by previous measurements using one epoch each with the Very Large Telescope and the Keck telescope; and (3) a velocity dispersion estimate for the field itself, which is likely dominated by the inner Galactic bulge and the nuclear disk.

  12. Characterization of a commercial hybrid iterative and model-based reconstruction algorithm in radiation oncology

    SciTech Connect (OSTI)

    Price, Ryan G.; Vance, Sean; Cattaneo, Richard; Elshaikh, Mohamed A.; Chetty, Indrin J.; Glide-Hurst, Carri K.; Schultz, Lonni

    2014-08-15

    Purpose: Iterative reconstruction (IR) reduces noise, thereby allowing dose reduction in computed tomography (CT) while maintaining comparable image quality to filtered back-projection (FBP). This study sought to characterize image quality metrics, delineation, dosimetric assessment, and other aspects necessary to integrate IR into treatment planning. Methods: CT images (Brilliance Big Bore v3.6, Philips Healthcare) were acquired of several phantoms using 120 kVp and 25–800 mAs. IR was applied at levels corresponding to noise reduction of 0.89–0.55 with respect to FBP. Noise power spectrum (NPS) analysis was used to characterize noise magnitude and texture. CT to electron density (CT-ED) curves were generated over all IR levels. Uniformity as well as spatial and low contrast resolution were quantified using a CATPHAN phantom. Task specific modulation transfer functions (MTF{sub task}) were developed to characterize spatial frequency across objects of varied contrast. A prospective dose reduction study was conducted for 14 patients undergoing interfraction CT scans for high-dose rate brachytherapy. Three physicians performed image quality assessment using a six-point grading scale between the normal-dose FBP (reference), low-dose FBP, and low-dose IR scans for the following metrics: image noise, detectability of the vaginal cuff/bladder interface, spatial resolution, texture, segmentation confidence, and overall image quality. Contouring differences between FBP and IR were quantified for the bladder and rectum via overlap indices (OI) and Dice similarity coefficients (DSC). Line profile and region of interest analyses quantified noise and boundary changes. For two subjects, the impact of IR on external beam dose calculation was assessed via gamma analysis and changes in digitally reconstructed radiographs (DRRs) were quantified. Results: NPS showed large reduction in noise magnitude (50%), and a slight spatial frequency shift (?0.1 mm{sup ?1}) with application of IR at L6. No appreciable changes were observed for CT-ED curves between FBP and IR levels [maximum difference ?13 HU for bone (?1% difference)]. For uniformity, differences were ?1 HU between FBP and IR. Spatial resolution was well conserved; the largest MTF{sub task} decrease between FBP and IR levels was 0.08 A.U. No notable changes in low-contrast detectability were observed and CNR increased substantially with IR. For the patient study, qualitative image grading showed low-dose IR was equivalent to or slightly worse than normal dose FBP, and is superior to low-dose FBP (p < 0.001 for noise), although these did not translate to differences in CT number, contouring ability, or dose calculation. The largest CT number discrepancy from FBP occurred at a bone/tissue interface using the most aggressive IR level [?1.2 ± 4.9 HU (range: ?17.6–12.5 HU)]. No clinically significant contour differences were found between IR and FBP, with OIs and DSCs ranging from 0.85 to 0.95. Negligible changes in dose calculation were observed. DRRs preserved anatomical detail with <2% difference in intensity from FBP combined with aggressive IRL6. Conclusions: These results support integrating IR into treatment planning. While slight degradation in edges and shift in texture were observed in phantom, patient results show qualitative image grading, contouring ability, and dosimetric parameters were not adversely affected.

  13. Irradiation Planning for Fully-Ceramic Micro-encsapsulated fuel in ATR at LWR-relevant conditions: year-end report on FY-2011

    SciTech Connect (OSTI)

    Abderrafi M. Ougouag; R. Sonat Sen; Michael A. Pope; Brian Boer

    2011-09-01

    This report presents the estimation of required ATR irradiation levels for the DB-FCM fuel design (fueled with Pu and MAs). The fuel and assembly designs are those considered in a companion report [R. S. Sen et al., FCR&D-2011- 00037 or INL/EXT-11-23269]. These results, pertaining to the DB-FCM fuel, are definitive in as much as the design of said fuel is definitive. In addition to the work performed, as required, for DB-FCM fuel, work has started in a preliminary fashion on single-cell UO2 and UN fuels. These latter activities go beyond the original charter of this project and although the corresponding work is incomplete, significant progress has been achieved. However, in this context, all that has been achieved is only preliminary because the corresponding fuel designs are neither finalized nor optimized. In particular, the UO2 case is unlikely to result in a viable fuel design if limited to enrichment at or under 20 weight % in U-235. The UN fuel allows reasonable length cycles and is likely to make an optimal design possible. Despite being limited to preliminary designs and offering only preliminary conclusions, the irradiation planning tasks for UO2 and UN fuels that are summarized in this report are useful to the overall goal of devising and deploying FCM-LWR fuel since the methods acquired and tested in this project and the overall procedure for planning will be available for planning tests for the finalized fuel design. Indeed, once the fuel design is finalized and the expected burnup level is determined, the methodology that has been assembled will allow the prompt finalization of the neutronic planning of the irradiation experiment and would provide guidance on the expected experimental performance of the fuel. Deviations from the expected behavior will then have to be analyzed and the outcome of the analysis may be corrections or modifications for the assessment models as well as, possibly, fuel design modifications, and perhaps even variation of experimental control for future experimental phases. Besides the prediction of irradiation times, preliminary work was carried out on other aspects of irradiation planning. In particular, a method for evaluating the interplay of depletion, material performance modeling and irradiation is identified by reference to a companion report. Another area that was addressed in a preliminary fashion is the identification and selection of a strategy for the physical and mechanical design of the irradiation experiments. The principal conclusion is that the similarity between the FCM fuel and the fuel compacts of the Next Generation Nuclear Plant prismatic design are strong enough to warrant using irradiation hardware designs and instrumentation adapted from the AGR irradiation tests. Modifications, if found necessary, will probably be few and small, except as pertains to the water environment and its implications on the use of SiC cladding or SiC matrix with no additional cladding.

  14. Capture of Anastrepha species (Diptera: Tephritidae) with multilure traps and biolure attractants in Guatemala

    SciTech Connect (OSTI)

    Martinez, A.J.; Salinas, E.J. [USDA-APHIS-PPQ-CPHST, 22675 N. Moorefield Rd, Edinburg, TX 78541-5033 (United States); Rendon, P. [USDA-APHIS-PPQ-CPHST, 4a Avenida 12-62, Zona 10, Guatemala City (Guatemala)

    2007-03-15

    Two trapping systems were compared in a study in Guatemala during the wet season, May through Dec 2001. Trap/lure combinations consisting of green or yellow-based plastic McPhail-like traps baited with a synthetic 2-component lure (putrescine and ammonium acetate) and 300 mL of propylene glycol antifreeze as a preservative were compared to the traditional glass McPhail baited with torula yeast/borax and 300 mL of water. Both systems captured several key Anastrepha species including Anastrepha ludens Loew, A. obliqua, Macquart, A. serpentina Weidemann, A. striata Schiner, A. distincta Greene, A. fraterculus Weidemann as well as Ceratitis capitata Weidemann. Additionally, 13 other Anastrepha spp. were captured with the synthetic lure. The plastic traps captured more key flies than the McPhail trap except for A. distincta where there were no significant differences between the yellow-based plastic trap and the McPhail trap and no significant differences between any trap and lure for trapping A. fraterculus. The synthetic lure lasted 10 weeks. The sex ratio was female-biased for almost all captured key species in both systems. Moreover, there were significant numbers of captured nontarget insects in all traps; however, the captured flies in those traps with the synthetic lure were not adversely affected by these insects. Propylene glycol-based antifreeze was a superior preservative when compared to borax/water. (author) [Spanish] En Guatemala, se compararon dos sistemas de trampeo durante la epoca lluviosa de Mayo a Deciembre, 2001. Combinaciones de trampa/atrayente que consistieron de trampas de plastico con bases verdes o amarillos y con atrayentes sinteticos (acetate de amoniaco y putrecina) fueron comparadas con el sistema de trampeo tradicional McPhail de vidrio cebada con torula y borax en agua. Los dos sistemas capturaron moscas del genero Anastrepha incluyendo Anastrepha ludens Loew, A. obliqua, Macquart, A. serpentina Weidemann, A. striata Schiner, A. distincta Greene, A. fraterculus Weidemann y Ceratitis capitata Weidemann. Ademas, se capturaron 13 especias adicionales de Anastrepha asi como Toxotrypana curvicauda Gerstaecker con el cebo sintetico. El cebo sintetico fue efectivo por diez semanas sin recebar. Las trampas de plastico capturaron mas moscas del genero Anastrepha que la trampa de cristal McPhail. Las excepciones fueron A. distincta en donde no hubo differencias el la captura con la trampa de plastico con base amarillo y la trampa McPhail de cristal asi como A. fraterculus en donde no hubo differencias comparando la captura de moscas con ambos sistemas. La proporcion sexual de las moscas capturadas con los dos sistemas fue al favor de las hembras. La captura de otros tipos de insectos fue significantemente elevado, sin embargo, las moscas capturadas con los cebos sinteticos no fueron afectados adversamente por estos insectos. El 10% del anticongelante, glicol propilico, fue superior al borax/agua como conservador de las moscas capturardas. (author)

  15. Development of a dynamic quality assurance testing protocol for multisite clinical trial DCE-CT accreditation

    SciTech Connect (OSTI)

    Driscoll, B.; Keller, H.; Jaffray, D.; Coolens, C.; Department of Radiation Oncology, University of Toronto, 150 College Street, Toronto, Ontario M5S 3E2; Techna Institute, University Health Network, 124-100 College Street, Toronto, Ontario M5G 1L5

    2013-08-15

    Purpose: Credentialing can have an impact on whether or not a clinical trial produces useful quality data that is comparable between various institutions and scanners. With the recent increase of dynamic contrast enhanced-computed tomography (DCE-CT) usage as a companion biomarker in clinical trials, effective quality assurance, and control methods are required to ensure there is minimal deviation in the results between different scanners and protocols at various institutions. This paper attempts to address this problem by utilizing a dynamic flow imaging phantom to develop and evaluate a DCE-CT quality assurance (QA) protocol.Methods: A previously designed flow phantom, capable of producing predictable and reproducible time concentration curves from contrast injection was fully validated and then utilized to design a DCE-CT QA protocol. The QA protocol involved a set of quantitative metrics including injected and total mass error, as well as goodness of fit comparison to the known truth concentration curves. An additional region of interest (ROI) sensitivity analysis was also developed to provide additional details on intrascanner variability and determine appropriate ROI sizes for quantitative analysis. Both the QA protocol and ROI sensitivity analysis were utilized to test variations in DCE-CT results using different imaging parameters (tube voltage and current) as well as alternate reconstruction methods and imaging techniques. The developed QA protocol and ROI sensitivity analysis was then applied at three institutions that were part of clinical trial involving DCE-CT and results were compared.Results: The inherent specificity of robustness of the phantom was determined through calculation of the total intraday variability and determined to be less than 2.2 ± 1.1% (total calculated output contrast mass error) with a goodness of fit (R{sup 2}) of greater than 0.99 ± 0.0035 (n= 10). The DCE-CT QA protocol was capable of detecting significant deviations from the expected phantom result when scanning at low mAs and low kVp in terms of quantitative metrics (Injected Mass Error 15.4%), goodness of fit (R{sup 2}) of 0.91, and ROI sensitivity (increase in minimum input function ROI radius by 146 ± 86%). These tests also confirmed that the ASIR reconstruction process was beneficial in reducing noise without substantially increasing partial volume effects and that vendor specific modes (e.g., axial shuttle) did not significantly affect the phantom results. The phantom and QA protocol were finally able to quickly (<90 min) and successfully validate the DCE-CT imaging protocol utilized at the three separate institutions of a multicenter clinical trial; thereby enhancing the confidence in the patient data collected.Conclusions: A DCE QA protocol was developed that, in combination with a dynamic multimodality flow phantom, allows the intrascanner variability to be separated from other sources of variability such as the impact of injection protocol and ROI selection. This provides a valuable resource that can be utilized at various clinical trial institutions to test conformance with imaging protocols and accuracy requirements as well as ensure that the scanners are performing as expected for dynamic scans.

  16. Enhancing BWR Proliferation Resistance Fuel with Minor Actinides

    SciTech Connect (OSTI)

    Gray S. Chang

    2008-07-01

    Key aspects of the Global Nuclear Energy Partnership (GNEP) are to significantly advance the science and technology of nuclear energy systems and the Advanced Fuel Cycle (AFC) program. It consists of both innovative nuclear reactors and innovative research in separation and transmutation. To accomplish these goals, international cooperation is very important and public acceptance is crucial. The merits of nuclear energy are high-density energy, with low environmental impacts (i.e. almost zero greenhouse gas emission). Planned efforts involve near-term and intermediate-term improvements in fuel utilization and recycling in current light water reactors (LWRs) as well as the longer-term development of new nuclear energy systems that offer much improved fuel utilization and proliferation resistance, along with continued advances in operational safety. The challenges are solving the energy needs of the world, protection against nuclear proliferation, the problem of nuclear waste, and the global environmental problem. To reduce spent fuel for storage and enhance the proliferation resistance for the intermediate-term, there are two major approaches (a) increase the discharged spent fuel burnup in the advanced LWR (Gen-III Plus), which not only can reduce the spent fuel for storage, but also increase the 238Pu and 240Pu isotopes ratio to enhance the proliferation resistance, and (b) use of transuranic nuclides (237Np and 241Am) in the high burnup fuel, which can drastically increase the proliferation resistance isotope ratio of 238Pu /Pu. For future advanced nuclear systems, the minor actinides (MA) are viewed more as a resource to be recycled, or transmuted to less hazardous and possibly more useful forms, rather than simply as a waste stream to be disposed of in expensive repository facilities. As a result, MAs play a much larger part in the design of advanced systems and fuel cycles, not only as additional sources of useful energy, but also as direct contributors to the reactivity control of the systems into which they are incorporated. In the study, a typical boiling water reactor (BWR) fuel unit lattice cell model with UO2 fuel pins will be used to investigate the effectiveness of minor actinide reduction approach (MARA) for enhancing proliferation resistance and improving the fuel cycle performance in the intermediate term goal for future nuclear energy systems. To account for the water coolant density variation from the bottom (0.76 g/cm3) to the top (0.35 g/cm3) of the core, the axial coolant channel and fuel pin were divided to 24 nodes. The MA transmutation characteristics at different elevations were compared and their impact on neutronics criticality discussed. We concluded that the concept of MARA, which involves the use of transuranic nuclides (237Np and/or 241Am), significantly increases the 238Pu/Pu ratio for proliferation resistance, as well as serves as a burnable absorber to hold-down the initial excess reactivity. It is believed that MARA can play an important role in atoms for peace and the intermediate term of nuclear energy rennaissance.

  17. A SURVEY OF STELLAR FAMILIES: MULTIPLICITY OF SOLAR-TYPE STARS

    SciTech Connect (OSTI)

    Raghavan, Deepak; McAlister, Harold A.; Henry, Todd J.; Gies, Douglas R.; White, Russel J.; Latham, David W.; Marcy, Geoffrey W.; Mason, Brian D.; Ten Brummelaar, Theo A.

    2010-09-15

    We present the results of a comprehensive assessment of companions to solar-type stars. A sample of 454 stars, including the Sun, was selected from the Hipparcos catalog with {pi}>40 mas, {sigma}{sub {pi}/{pi}} < 0.05, 0.5 {<=} B - V {<=} 1.0 ({approx}F6-K3), and constrained by absolute magnitude and color to exclude evolved stars. These criteria are equivalent to selecting all dwarf and subdwarf stars within 25 pc with V-band flux between 0.1 and 10 times that of the Sun, giving us a physical basis for the term 'solar-type'. New observational aspects of this work include surveys for (1) very close companions with long-baseline interferometry at the Center for High Angular Resolution Astronomy Array, (2) close companions with speckle interferometry, and (3) wide proper-motion companions identified by blinking multi-epoch archival images. In addition, we include the results from extensive radial-velocity monitoring programs and evaluate companion information from various catalogs covering many different techniques. The results presented here include four new common proper-motion companions discovered by blinking archival images. Additionally, the spectroscopic data searched reveal five new stellar companions. Our synthesis of results from many methods and sources results in a thorough evaluation of stellar and brown dwarf companions to nearby Sun-like stars. The overall observed fractions of single, double, triple, and higher-order systems are 56% {+-} 2%, 33% {+-} 2%, 8% {+-} 1%, and 3% {+-} 1%, respectively, counting all confirmed stellar and brown dwarf companions. If all candidate, i.e., unconfirmed, companions identified are found to be real, the percentages would change to 54% {+-} 2%, 34% {+-} 2%, 9% {+-} 2%, and 3% {+-} 1%, respectively. Our completeness analysis indicates that only a few undiscovered companions remain in this well-studied sample, implying that the majority (54% {+-} 2%) of solar-type stars are single, in contrast to the results of prior multiplicity studies. Our sample is large enough to enable a check of the multiplicity dependence on various physical parameters by analyzing appropriate subsamples. Bluer, more massive stars are seen as more likely to have companions than redder, less massive ones, consistent with the trend seen over the entire spectral range. Systems with larger interaction cross sections, i.e., those with more than two components or long orbital periods, are preferentially younger, suggesting that companions may be stripped over time by dynamical interactions. We confirm the planet-metallicity correlation (i.e., higher metallicity stars are more likely to host planets), but are unable to check it for brown dwarfs due to the paucity of such companions, implying that the brown dwarf desert extends over all separation regimes. We find no correlation between stellar companions and metallicity for B - V < 0.625, but among the redder subset, metal-poor stars ([Fe/H] <-0.3) are more likely to have companions with a 2.4{sigma} significance. The orbital-period distribution of companions is unimodal and roughly log normal with a peak and median of about 300 years. The period-eccentricity relation shows the expected circularization for periods below 12 days, caused by tidal forces over the age of the Galaxy, followed by a roughly flat distribution. The mass-ratio distribution shows a preference for like-mass pairs, which occur more frequently in relatively close pairs. The fraction of planet hosts among single, binary, and multiple systems are statistically indistinguishable, suggesting that planets are as likely to form around single stars as they are around components of binary or multiple systems with sufficiently wide separations. This, along with the preference of long orbital periods among stellar systems, increases the space around stars conducive for planet formation, and perhaps life.

  18. Crystal-chemistry of mullite-type aluminoborates Al{sub 18}B{sub 4}O{sub 33} and Al{sub 5}BO{sub 9}: A stoichiometry puzzle

    SciTech Connect (OSTI)

    Fisch, Martin; Armbruster, Thomas; Rentsch, Daniel; Libowitzky, Eugen; Pettke, Thomas

    2011-01-15

    Orthorhombic Al{sub 2}O{sub 3}-rich aluminoborate is an important ceramic material for which two slightly different compositions have been assumed: Al{sub 5}BO{sub 9} (5Al{sub 2}O{sub 3}:B{sub 2}O{sub 3}) and Al{sub 18}B{sub 4}O{sub 33} (9Al{sub 2}O{sub 3}:2B{sub 2}O{sub 3}). The formula Al{sub 18}B{sub 4}O{sub 33} (=Al{sub 4.91}B{sub 1.09}O{sub 9}) was derived from results of chemical analyses when crystal structure data were not yet available. Subsequent structural investigations indicated Al{sub 5}BO{sub 9} composition. Nevertheless, Al{sub 18}B{sub 4}O{sub 33} was still accepted as the correct stoichiometry assuming that additional B replaces 9% Al. Powder samples of both compositions and ones with excess boron were prepared by solid state reactions between {alpha}-Al{sub 2}O{sub 3} and B{sub 2}O{sub 3}/H{sub 3}BO{sub 3} at temperatures above 1100 {sup o}C and single-crystals were grown from flux at 1100 and 1550 {sup o}C. Products were investigated by single-crystal and powder XRD, {sup 11}B and {sup 27}Al solid-state MAS-NMR, Raman and FTIR spectroscopy as well as Laser-ablation ICP-MS. No indication of the predicted 9% B{yields}Al substitution was found. LA ICP-MS indicated 12.36(27) wt% B{sub 2}O{sub 3} corresponding to Al{sub 4.97}B{sub 1.03}O{sub 9}. Hence, the suggested Al{sub 18}B{sub 4}O{sub 33} stoichiometry can be excluded for all synthesized samples. A very low amount of Al vacancies at a five-fold coordinated site are likely, charge balanced by an additional nearby three-fold coordinated B site. All evidences indicate that the title compound should be reported as Al{sub 5-x}B{sub 1+x}O{sub 9} with x<0.038(6), which is close to Al{sub 5}BO{sub 9}. -- Graphical abstract: A chemical composition of Al{sub 18}B{sub 4}O{sub 33}=Al{sub 4.91}B{sub 1.09}O{sub 9}=9Al{sub 2}O{sub 3}:2B{sub 2}O{sub 3} has been assumed for mullite-type aluminoborate with Al{sub 5}BO{sub 9} structure. However, samples prepared by different routes showed compositions close to 5Al{sub 2}O{sub 3}:B{sub 2}O{sub 3}. Display Omitted