Science.gov

Sample records for em videiras nas

  1. A estabilidade dos PAHS em função da energia da radiação interestelar nas faixas UV e raios-X

    NASA Astrophysics Data System (ADS)

    Pinotti, R.; Costa, R. K.; Boechat-Roberty, H. M.; Lago, A.; Souza, G. B.

    2003-08-01

    A nebulosa CRL 618, uma proto-nebulosa planetária cuja nuvem molecular espessa envolve uma estrela B0, contém uma grande quantidade de C2H2 e CH4. Estas moléculas são consideradas os tijolos da criação de grandes moléculas carbonadas como os Hidrocarbonetos Policíclicos Aromáticos (PAHs). Esta nebulosa, por estar exposta a intensos campos de UV e Raios-X, é uma região de fotodissociação molecular que propicia a formação de novas moléculas, confirmada pela presença de C4H2 e C6H6 (Benzeno), que é a unidade básica dos PAHs. Atribui-se a esta família de moléculas orgânicas duas propriedades fundamentais, a resistência para sobreviver ao campo de radiação UV interestelar e a geração das bandas de emissão não identificadas (UIR) observadas no infravermelho. No entanto, alguns autores questionam a resistência dos PAHs ao campo de radiação UV interestelar. Empregando a técnica de Espectrometria de Massas por Tempo de Vôo, no modo de coincidência fotoelétron-fotoíon, estudamos a ionização e fragmentação das seguintes moléculas: Benzeno, Benzeno deuterado, Naftaleno, Antraceno e Fenantreno. Utilizamos uma fonte de Hélio monocromática em 21,21 eV (584,5 Å) e a radiação Síncroton do Laboratório Nacional de Luz Síncroton (LNLS) em diferentes energias nas proximidades da borda do C 1s ( 290 eV). Comprovamos a estabilidade dos PAHs sob ação de UV (21,21 eV), onde eles apresentam um baixo nível de fotodissociação, produzindo fragmentos ionizados com rendimento total na ordem de 5 por cento em relação ao íon molecular pai. Entretanto, em altas energias, na faixa de Raios-X, a quebra destas moléculas torna-se mais intensa, com a produção de muitos fragmentos. Como uma das rotas de fragmentação do Naftaleno é [(C10H8) = > (C6H6+) + (C4H2) + (e-)], e como temos as evidências observacionais da existência do C4H2 e C6H6 na nebulosa CRL 618, sugerimos que este ambiente também possui o Naftaleno.

  2. NAS: The first year

    NASA Technical Reports Server (NTRS)

    Bailey, F. R.; Kutler, Paul

    1988-01-01

    Discussed are the capabilities of NASA's Numerical Aerodynamic Simulation (NAS) Program and its application as an advanced supercomputing system for computational fluid dynamics (CFD) research. First, the paper describes the NAS computational system, called the NAS Processing System Network, and the advanced computational capabilities it offers as a consequence of carrying out the NAS pathfinder objective. Second, it presents examples of pioneering CFD research accomplished during NAS's first operational year. Examples are included which illustrate CFD applications for predicting fluid phenomena, complementing and supplementing experimentation, and aiding in design. Finally, pacing elements and future directions for CFD and NAS are discussed.

  3. New NAS journal

    NASA Astrophysics Data System (ADS)

    In April 1984 the National Academy of Sciences (NAS) will begin publishing a new quarterly focusing on science policy. Written primarily for legislators, diplomats, corporate managers, security analysts, and other public policy analysts, the new journal will deal with such diverse topics as arms control, economic competition, social change, and health care.Original articles are expected to create a 120-page periodical that will discuss policy issues on a sophisticated but nonspecialist level, in a manner similar to that which Foreign Affairs uses to discuss U.S. foreign policy topics, according to NAS.

  4. Numerical Aerodynamic Simulation (NAS)

    NASA Technical Reports Server (NTRS)

    Peterson, V. L.; Ballhaus, W. F., Jr.; Bailey, F. R.

    1983-01-01

    The history of the Numerical Aerodynamic Simulation Program, which is designed to provide a leading-edge capability to computational aerodynamicists, is traced back to its origin in 1975. Factors motivating its development and examples of solutions to successively refined forms of the governing equations are presented. The NAS Processing System Network and each of its eight subsystems are described in terms of function and initial performance goals. A proposed usage allocation policy is discussed and some initial problems being readied for solution on the NAS system are identified.

  5. NATIONAL ALCOHOL SURVEY (NAS)

    EPA Science Inventory

    National Alcohol Survey (NAS) is designed to assess the trends in drinking practices and problems in the national population, including attitudes, norms, treatment and experiences and adverse consequences. It also studies the effects of public policy on drinking practices (i.e., ...

  6. The NAS Parallel Benchmarks

    SciTech Connect

    Bailey, David H.

    2009-11-15

    The NAS Parallel Benchmarks (NPB) are a suite of parallel computer performance benchmarks. They were originally developed at the NASA Ames Research Center in 1991 to assess high-end parallel supercomputers. Although they are no longer used as widely as they once were for comparing high-end system performance, they continue to be studied and analyzed a great deal in the high-performance computing community. The acronym 'NAS' originally stood for the Numerical Aeronautical Simulation Program at NASA Ames. The name of this organization was subsequently changed to the Numerical Aerospace Simulation Program, and more recently to the NASA Advanced Supercomputing Center, although the acronym remains 'NAS.' The developers of the original NPB suite were David H. Bailey, Eric Barszcz, John Barton, David Browning, Russell Carter, LeoDagum, Rod Fatoohi, Samuel Fineberg, Paul Frederickson, Thomas Lasinski, Rob Schreiber, Horst Simon, V. Venkatakrishnan and Sisira Weeratunga. The original NAS Parallel Benchmarks consisted of eight individual benchmark problems, each of which focused on some aspect of scientific computing. The principal focus was in computational aerophysics, although most of these benchmarks have much broader relevance, since in a much larger sense they are typical of many real-world scientific computing applications. The NPB suite grew out of the need for a more rational procedure to select new supercomputers for acquisition by NASA. The emergence of commercially available highly parallel computer systems in the late 1980s offered an attractive alternative to parallel vector supercomputers that had been the mainstay of high-end scientific computing. However, the introduction of highly parallel systems was accompanied by a regrettable level of hype, not only on the part of the commercial vendors but even, in some cases, by scientists using the systems. As a result, it was difficult to discern whether the new systems offered any fundamental performance advantage

  7. NAS Parallel Benchmarks Results

    NASA Technical Reports Server (NTRS)

    Subhash, Saini; Bailey, David H.; Lasinski, T. A. (Technical Monitor)

    1995-01-01

    The NAS Parallel Benchmarks (NPB) were developed in 1991 at NASA Ames Research Center to study the performance of parallel supercomputers. The eight benchmark problems are specified in a pencil and paper fashion i.e. the complete details of the problem to be solved are given in a technical document, and except for a few restrictions, benchmarkers are free to select the language constructs and implementation techniques best suited for a particular system. In this paper, we present new NPB performance results for the following systems: (a) Parallel-Vector Processors: Cray C90, Cray T'90 and Fujitsu VPP500; (b) Highly Parallel Processors: Cray T3D, IBM SP2 and IBM SP-TN2 (Thin Nodes 2); (c) Symmetric Multiprocessing Processors: Convex Exemplar SPP1000, Cray J90, DEC Alpha Server 8400 5/300, and SGI Power Challenge XL. We also present sustained performance per dollar for Class B LU, SP and BT benchmarks. We also mention NAS future plans of NPB.

  8. NAS Applications and Advanced Algorithms

    NASA Technical Reports Server (NTRS)

    Bailey, David H.; Biswas, Rupak; VanDerWijngaart, Rob; Kutler, Paul (Technical Monitor)

    1997-01-01

    This paper examines the applications most commonly run on the supercomputers at the Numerical Aerospace Simulation (NAS) facility. It analyzes the extent to which such applications are fundamentally oriented to vector computers, and whether or not they can be efficiently implemented on hierarchical memory machines, such as systems with cache memories and highly parallel, distributed memory systems.

  9. NASA's UAS NAS Access Project

    NASA Technical Reports Server (NTRS)

    Johnson, Charles W.

    2011-01-01

    The vision of the Unmanned Aircraft System (UAS) Integration in the National Airspace System (NAS) Project is "A global transportation system which allows routine access for all classes of UAS." The goal of the UAS Integration in the NAS Project is to "contribute capabilities that reduce technical barriers related to the safety and operational challenges associated with enabling routine UAS access to the NAS." This goal will be accomplished through a two-phased approach based on development of system-level integration of key concepts, technologies and/or procedures, and demonstrations of integrated capabilities in an operationally relevant environment. Phase 1 will take place the first two years of the Project and Phase 2 will take place the following three years. The Phase 1 and 2 technical objectives are: Phase 1: Developing a gap analysis between current state of the art and the Next Generation Air Transportation System (NextGen) UAS Concept of Operations . Validating the key technical areas identified by this Project . Conducting initial modeling, simulation, and flight testing activities . Completing Sub-project Phase 1 deliverables (spectrum requirements, comparative analysis of certification methodologies, etc.) and continue Phase 2 preparation (infrastructure, tools, etc.) Phase 2: Providing regulators with a methodology for developing airworthiness requirements for UAS, and data to support development of certifications standards and regulatory guidance . Providing systems-level, integrated testing of concepts and/or capabilities that address barriers to routine access to the NAS. Through simulation and flight testing, address issues including separation assurance, communications requirements, and human systems integration in operationally relevant environments. The UAS in the NAS Project will demonstrate solutions in specific technology areas, which will address operational/safety issues related to UAS access to the NAS. Since the resource allocation for

  10. New NAS Parallel Benchmarks Results

    NASA Technical Reports Server (NTRS)

    Yarrow, Maurice; Saphir, William; VanderWijngaart, Rob; Woo, Alex; Kutler, Paul (Technical Monitor)

    1997-01-01

    NPB2 (NAS (NASA Advanced Supercomputing) Parallel Benchmarks 2) is an implementation, based on Fortran and the MPI (message passing interface) message passing standard, of the original NAS Parallel Benchmark specifications. NPB2 programs are run with little or no tuning, in contrast to NPB vendor implementations, which are highly optimized for specific architectures. NPB2 results complement, rather than replace, NPB results. Because they have not been optimized by vendors, NPB2 implementations approximate the performance a typical user can expect for a portable parallel program on distributed memory parallel computers. Together these results provide an insightful comparison of the real-world performance of high-performance computers. New NPB2 features: New implementation (CG), new workstation class problem sizes, new serial sample versions, more performance statistics.

  11. EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments (External Review Draft)

    EPA Science Inventory

  1. Status and projections of the NAS program

    NASA Technical Reports Server (NTRS)

    Bailey, Frank R.

    1986-01-01

    NASA's Numerical Aerodynamic Simulation (NAS) Program has completed development of the initial operating configuration of the NAS Processing System Network (NPSN). This is the first milestone in the continuing and pathfinding effort to provide state-of-the-art supercomputing for aeronautics research and development. The NPSN, available to a nation-wide community of remote users, provides a uniform UNIX environment over a network of host computers ranging from the Cray-2 supercomputer to advanced scientific workstations. This system, coupled with a vendor-independent base of common user interface and network software, presents a new paradigm for supercomputing environments. Background leading to the NAS program, its programmatic goals and strategies, technical goals and objectives, and the development activities leading to the current NPSN configuration are presented. Program status, near-term plans, and plans for the next major milestone, the extended operating configuration, are also discussed.

  2. UAS Integration into the NAS Project

    NASA Technical Reports Server (NTRS)

    Bauer, Jeff

    2010-01-01

    The goal of the UAS Integration in the NAS Project is to contribute capabilities that reduce technical barriers related to the safety and operational challenges associated with enabling routine UAS access to the NAS This goal will be accomplished through a two-phased approach of system-level integration of key concepts, technologies and/or procedures, and demonstrations of integrated capabilities in an operationally relevant environment. Technical objectives include: PHASE 1: a) Validating the key technical areas identified by this project. System-level analyses, a State of the Art Analysis (SOAA), and a ConOps will identify the challenges and barriers preventing routine UAS access to the NAS. b) Developing a national roadmap and gap analysis identifying specific deliverables in the area of operations, procedures, and technologies that will impact future policy decisions. PHASE 2: a) Provide regulators with a methodology for developing airworthiness requirements for UAS and data to support development of certifications standards and regulatory guidance. b) Provide systems-level integrated testing of concepts and/or capabilities that address barriers to routine access to the NAS. Through simulation and flight testing, address issues including separation assurance, communications requirements, and Pilot Aircraft Interfaces (PAIs) in operationally relevant environments

  3. Security Controls Hurt Research, NAS Warns.

    ERIC Educational Resources Information Center

    Kolata, Gina

    1982-01-01

    A National Academy of Sciences (NAS) report found no evidence that leaks of technical information from universities or other research centers have damaged national security. However, in areas where control is warranted, decisions should be based on criteria. These criteria and issues related to security control and technological transfer are…

  4. UAS Integration in the NAS Project - Project Overview

    NASA Technical Reports Server (NTRS)

    Johnson, Chuck

    2011-01-01

    The goal of the UAS integration in the NAS Project is to contribute capabili1es that reduce technical barriers related to the safety and opera1onal challenges associated with enabling routine UAS access to the NAS.

  5. NAS Panel endorses science center concept

    NASA Astrophysics Data System (ADS)

    Science and technology centers, as proposed by President Ronald Reagan in his January 1987 State of the Union message, could make “significant contributions to science and to the nation's economic competitiveness,” according to a new report by a National Academy of Sciences (NAS) panel. What will be necessary to realize these contributions, the panel cautioned, are proper management, adequate resources, and, “above all, the selection of programs for which the centers are the most effective form of organization.”NSF plans to support science and technology centers, beginning October 1, 1988, which is the start of fiscal year 1988. NSF requested guidance from the NAS panel in implementing the program. Although other government agencies will participate in the program, NSF will play the primary role.

  6. NAS Grid Benchmarks. 1.0

    NASA Technical Reports Server (NTRS)

    VanderWijngaart, Rob; Frumkin, Michael; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    We provide a paper-and-pencil specification of a benchmark suite for computational grids. It is based on the NAS (NASA Advanced Supercomputing) Parallel Benchmarks (NPB) and is called the NAS Grid Benchmarks (NGB). NGB problems are presented as data flow graphs encapsulating an instance of a slightly modified NPB task in each graph node, which communicates with other nodes by sending/receiving initialization data. Like NPB, NGB specifies several different classes (problem sizes). In this report we describe classes S, W, and A, and provide verification values for each. The implementor has the freedom to choose any language, grid environment, security model, fault tolerance/error correction mechanism, etc., as long as the resulting implementation passes the verification test and reports the turnaround time of the benchmark.

  7. NAS Technical Summaries, March 1993 - February 1994

    NASA Technical Reports Server (NTRS)

    1995-01-01

    NASA created the Numerical Aerodynamic Simulation (NAS) Program in 1987 to focus resources on solving critical problems in aeroscience and related disciplines by utilizing the power of the most advanced supercomputers available. The NAS Program provides scientists with the necessary computing power to solve today's most demanding computational fluid dynamics problems and serves as a pathfinder in integrating leading-edge supercomputing technologies, thus benefitting other supercomputer centers in government and industry. The 1993-94 operational year concluded with 448 high-speed processor projects and 95 parallel projects representing NASA, the Department of Defense, other government agencies, private industry, and universities. This document provides a glimpse at some of the significant scientific results for the year.

  8. Implementation of NAS Parallel Benchmarks in Java

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael; Schultz, Matthew; Jin, Hao-Qiang; Yan, Jerry

    2000-01-01

    A number of features make Java an attractive but a debatable choice for High Performance Computing (HPC). In order to gauge the applicability of Java to the Computational Fluid Dynamics (CFD) we have implemented NAS Parallel Benchmarks in Java. The performance and scalability of the benchmarks point out the areas where improvement in Java compiler technology and in Java thread implementation would move Java closer to Fortran in the competition for CFD applications.

  9. NAS Parallel Benchmarks Results 3-95

    NASA Technical Reports Server (NTRS)

    Saini, Subhash; Bailey, David H.; Walter, Howard (Technical Monitor)

    1995-01-01

    The NAS Parallel Benchmarks (NPB) were developed in 1991 at NASA Ames Research Center to study the performance of parallel supercomputers. The eight benchmark problems are specified in a "pencil and paper" fashion, i.e., the complete details of the problem are given in a NAS technical document. Except for a few restrictions, benchmark implementors are free to select the language constructs and implementation techniques best suited for a particular system. In this paper, we present new NPB performance results for the following systems: (a) Parallel-Vector Processors: CRAY C90, CRAY T90 and Fujitsu VPP500; (b) Highly Parallel Processors: CRAY T3D, IBM SP2-WN (Wide Nodes), and IBM SP2-TN2 (Thin Nodes 2); and (c) Symmetric Multiprocessors: Convex Exemplar SPPIOOO, CRAY J90, DEC Alpha Server 8400 5/300, and SGI Power Challenge XL (75 MHz). We also present sustained performance per dollar for Class B LU, SP and BT benchmarks. We also mention future NAS plans for the NPB.

  10. Carrier spin relaxation in GaInNAsSb/GaNAsSb/GaAs quantum well

    SciTech Connect

    Asami, T.; Nosho, H.; Tackeuchi, A.; Li, L. H.; Harmand, J. C.; Lu, S. L.

    2011-12-23

    We have investigated the carrier spin relaxation in GaInNAsSb/GaNAsSb/GaAs quantum well (QW) by time-resolved photoluminescence (PL) measurement. The sample consists of an 8-nm-thick GaIn{sub 0.36}N{sub 0.006}AsSb{sub 0.015} well, 5-nm-thick GaN{sub 0.01}AsSb{sub 0.11} intermediate barriers and 100-nm-thick GaAs barriers grown by molecular beam epitaxy on a GaAs(100) substrate. The spin relaxation time and recombination lifetime at 10 K are measured to be 228 ps and 151 ps, respectively. As a reference, we have also obtained a spin relaxation time of 125 ps and a recombination lifetime of 63 ps for GaInNAs/GaNAs/GaAs QW. This result shows that crystal quality is slightly improved by adding Sb, although these short carrier lifetimes mainly originate from a nonradiative recombination. These spin relaxation times are longer than the 36 ps spin relaxation time of InGaAs/InP QWs and shorter than the 2 ns spin relaxation time of GaInNAs/GaAs QW.

  11. Dynamics of time-resolved photoluminescence in GaInNAs and GaNAsSb solar cells

    PubMed Central

    2014-01-01

    We report a time-resolved photoluminescence study for GaInNAs and GaNAsSb p-i-n bulk solar cells grown on GaAs(100). In particular, we studied the extent to which the carrier lifetime decreases with the increase of N content. Rapid thermal annealing proved to significantly increase the decay times by a factor of 10 to 12 times, for both GaInNAs and GaNAsSb heterostructures, while for the 1-eV bandgap GaNAsSb structure, grown at the same growth conditions as the GaInNAs, the photoluminescence decay time remained slightly below 100 ps after annealing; the approximately 1.15-eV GaInNAs p-i-n solar cell exhibited a lifetime as long as 900 ps. PACS 78.47.D; 78.55.Cr; 88.40.hj PMID:24533702

  12. NAS Parallel Benchmarks. 2.4

    NASA Technical Reports Server (NTRS)

    VanderWijngaart, Rob; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    We describe a new problem size, called Class D, for the NAS Parallel Benchmarks (NPB), whose MPI source code implementation is being released as NPB 2.4. A brief rationale is given for how the new class is derived. We also describe the modifications made to the MPI (Message Passing Interface) implementation to allow the new class to be run on systems with 32-bit integers, and with moderate amounts of memory. Finally, we give the verification values for the new problem size.

  13. Remote access for NAS: Supercomputing in a university environment

    NASA Technical Reports Server (NTRS)

    Johnson, G.; Olson, B.; Swisshelm, J.; Pryor, D.; Ziebarth, J.

    1986-01-01

    The experiment was designed to assist the Numerical Aerodynamic Simulation (NAS) Project Office in the testing and evaluation of long haul communications for remote users. The objectives of this work were to: (1) use foreign workstations to remotely access the NAS system; (2) provide NAS with a link to a large university-based computing facility which can serve as a model for a regional node of the Long-Haul Communications Subsystem (LHCS); and (3) provide a tail circuit to the University of Colorado a Boulder thereby simulating the complete communications path from NAS through a regional node to an end-user.

  14. NAS Parallel Benchmarks, Multi-Zone Versions

    NASA Technical Reports Server (NTRS)

    vanderWijngaart, Rob F.; Haopiang, Jin

    2003-01-01

    We describe an extension of the NAS Parallel Benchmarks (NPB) suite that involves solving the application benchmarks LU, BT and SP on collections of loosely coupled discretization meshes. The solutions on the meshes are updated independently, but after each time step they exchange boundary value information. This strategy, which is common among structured-mesh production flow solver codes in use at NASA Ames and elsewhere, provides relatively easily exploitable coarse-grain parallelism between meshes. Since the individual application benchmarks also allow fine-grain parallelism themselves, this NPB extension, named NPB Multi-Zone (NPB-MZ), is a good candidate for testing hybrid and multi-level parallelization tools and strategies.

  15. An Implementation Plan for NFS at NASA's NAS Facility

    NASA Technical Reports Server (NTRS)

    Lam, Terance L.; Kutler, Paul (Technical Monitor)

    1998-01-01

    This document discusses how NASA's NAS can benefit from the Sun Microsystems' Network File System (NFS). A case study is presented to demonstrate the effects of NFS on the NAS supercomputing environment. Potential problems are addressed and an implementation strategy is proposed.

  16. [The NAS system: Nursing Activities Score in mobile technology].

    PubMed

    Catalan, Vanessa Menezes; Silveira, Denise Tolfo; Neutzling, Agnes Ludwig; Martinato, Luísa Helena Machado; Borges, Gilberto Cabral de Mello

    2011-12-01

    The objective of this study was to present the computerized structure that enables the use of the Nursing Activities Score (NAS) in mobile technology. It is a project for the development of technology production based on software engineering, founded on the theory of systems development life cycle. The NAS system was built in two modules: the search module, which is accessed using a personal computer (PC), and Data Collection module, which is accessed through a mobile device (Smartphone). The NAS system was constructed to allow other forms, in addition to the NAS tool, to be included in the future. Thus, it is understood that the development of the NAS will bring nurses closer to mobile technology and facilitate their accessibility to the data of the instrument relating to patients, thus assisting in decision-making and in staffing to provide nursing care. PMID:22241201

  17. The Need for Vendor Source Code at NAS. Revised

    NASA Technical Reports Server (NTRS)

    Carter, Russell; Acheson, Steve; Blaylock, Bruce; Brock, David; Cardo, Nick; Ciotti, Bob; Poston, Alan; Wong, Parkson; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    The Numerical Aerodynamic Simulation (NAS) Facility has a long standing practice of maintaining buildable source code for installed hardware. There are two reasons for this: NAS's designated pathfinding role, and the need to maintain a smoothly running operational capacity given the widely diversified nature of the vendor installations. NAS has a need to maintain support capabilities when vendors are not able; diagnose and remedy hardware or software problems where applicable; and to support ongoing system software development activities whether or not the relevant vendors feel support is justified. This note provides an informal history of these activities at NAS, and brings together the general principles that drive the requirement that systems integrated into the NAS environment run binaries built from source code, onsite.

  18. Policy Recommendations to VA Leave NAS at Odds with Congress

    ERIC Educational Resources Information Center

    Walsh, John

    1978-01-01

    Describes adverse congressional reaction to a recent National Academy of Sciences (NAS) recommendation that the Veteran's Administration's (VA) health care system be phased into a general health care system. (SL)

  19. UAS Integration in the NAS Project - FY 14 Annual Review

    NASA Technical Reports Server (NTRS)

    Grindle, Laurie; Randall, Debra; Hackenberg, Davis

    2014-01-01

    This briefing gives insight into the research activities and efforts being executed in order to integrate unmanned aircraft systems into the national airspace system. This briefing is to inform others of the UAS-NAS Projects progress and future directions.

  20. UAS Integration in the NAS FY15 Annual Review

    NASA Technical Reports Server (NTRS)

    Grindle, Laurie; Randall, Debra; Hackenburg, Davis

    2015-01-01

    This presentation gives insight into the research activities and efforts being executed in order to integrate unmanned aircraft systems into the national airspace system. This briefing is to inform others of the UAS-NAS progress and future directions.

  1. The NAS Parallel Benchmarks 2.1 Results

    NASA Technical Reports Server (NTRS)

    Saphir, William; Woo, Alex; Yarrow, Maurice

    1996-01-01

    We present performance results for version 2.1 of the NAS Parallel Benchmarks (NPB) on the following architectures: IBM SP2/66 MHz; SGI Power Challenge Array/90 MHz; Cray Research T3D; and Intel Paragon. The NAS Parallel Benchmarks are a widely-recognized suite of benchmarks originally designed to compare the performance of highly parallel computers with that of traditional supercomputers.

  2. Experimental studies on atmospheric Stirling engine NAS-2

    SciTech Connect

    Watanabe, Hiroichi; Isshiki, Naotsugu; Ohtomo, Michihiro

    1996-12-31

    Atmospheric hot air Stirling engine NAS-1 and 2 have a simple flat rubber sheet diaphragm as their power piston, and they have been experimentally studied at Nihon University for several years continuously, with the target of to get more than 100 watts shaft power by atmospheric air with simple construction and cheap material. The first NAS-1 was intended to be a solar heated engine using television glass and wood for cheap cost, but it failed by thermal break of glass, so the improved NAS-2 is changed to be heated by gas burner, using metallic materials in all parts except rubber power piston. Other than this rubber sheet diaphragm, NAS-2 has many features as using James Watt crank mechanism, high finny copper tube for conventional commercial heat exchanger, and two kinds of hot gas heaters, etc. About the rubber sheet for the power piston, the thickness of the sheet was changed from 2 mm to 6 mm gradually to known what thickness is best, and it is found that about 5 mm is best for this engine. After trying many improvements on this engine, NAS-2 has produced about 130 watt shaft power with indicated power of 350 watt at 1994. In this paper detail of many features, history, results and experiments of these NAS engines are reported.

  3. Natural attenuation software (NAS): Assessing remedial strategies and estimating timeframes

    USGS Publications Warehouse

    Mendez, E.; Widdowson, M.; Chapelle, F.; Casey, C.

    2005-01-01

    Natural Attenuation Software (NAS) is a screening tool to estimate remediation timeframes for monitored natural attenuation (MNA) and to assist in decision-making on the level of source zone treatment in conjunction with MNA using site-specific remediation objectives. Natural attenuation processes that NAS models include are advection, dispersion, sorption, non-aqueous phase liquid (NAPL) dissolution, and biodegradation of either petroleum hydrocarbons or chlorinated ethylenes. Newly-implemented enhancements to NAS designed to maximize the utility of NAS for site managers were observed. NAS has expanded source contaminant specification options to include chlorinated ethanes and chlorinated methanes, and to allow for the analysis of any other user-defined contaminants that may be subject to microbially-mediated transformations (heavy metals, radioisotopes, etc.). Included is the capability to model co-mingled plumes, with constituents from multiple contaminant categories. To enable comparison of remediation timeframe estimates between MNA and specific engineered remedial actions , NAS was modified to incorporate an estimation technique for timeframes associated with pump-and-treat remediation technology for comparison to MNA. This is an abstract of a paper presented at the 8th International In Situ and On-Site Bioremediation Symposium (Baltimore, MD 6/6-9/2005).

  4. Photoreflectance spectroscopy of step-like GaInNAs/GaInNAs/GaAs quantum wells

    NASA Astrophysics Data System (ADS)

    Kudrawiec, R.; Andrzejewski, J.; Misiewicz, J.; Gollub, D.; Forchel, A.

    2005-05-01

    Photoreflectance (PR) spectroscopy has been applied to study of step-like GaInNAs/GaInNAs/GaAs double quantum well (DQW) structures grown by molecular beam epitaxy. PR features related to optical transitions in the active part of the step-like QW structure, i.e. GaInNAs/GaInNAs QW, as well as PR features related to transitions above the step-like barrier (SLB) have been clearly observed and analysed in this paper. The analysis of the QW transitions gives information about the number of confined states in the active part of the step-like QW structure. In addition, the analysis of the second portion of PR signal gives information about the band gap energy of the SLB and optical transitions between hole and electron levels confined above the SLB.

  5. RNA sequence requirements for NasR-mediated, nitrate-responsive transcription antitermination of the Klebsiella oxytoca M5al nasF operon leader.

    PubMed

    Chai, W; Stewart, V

    1999-09-17

    In Klebsiella oxytoca, enzymes required for nitrate assimilation are encoded by the nasFEDCBA operon. Nitrate and nitrite induction of nasF operon expression is determined by a transcriptional antitermination mechanism, in which the nasR gene product responds to nitrate or nitrite and overcomes transcription termination at the factor-independent terminator site located in the nasF upstream leader region. Previous studies led to the hypothesis that the NasR protein mediates transcription antitermination through interaction with nasF leader RNA. Here, we report a DNA sequence comparison that reveals conserved 1:2 and 3:4 RNA secondary structures in the nasF leader RNAs from two Klebsiella species. Additionally, we found that specific binding of the NasR protein to nasF leader RNA was stimulated by nitrate and nitrite. We combined mutational analysis, in vivo and in vitro antitermination assays, and an RNA electrophoretic mobility shift assay to define regions in the nasF leader that are essential for antitermination and for NasR-RNA interaction. Formation of the 1:2 stem structure and the specific sequence of the 1:2 hexanucleotide loop were required for both nitrate induction and for NasR-RNA interaction. Mutations in the 1:2 stem-loop region that abolished nitrate induction also interfered with NasR-leader RNA interaction. Finally, nucleotide alterations or additions in the linker region between the 1:2 and 3:4 stem-loops were deleterious to nasF operon induction but not to NasR-leader RNA interaction. We hypothesize that NasR protein recognizes the 1:2 stem-loop structure in the nasF leader RNA to mediate transcription antitermination in response to nitrate or nitrite. PMID:10493869

  6. National Air Space (NAS) Data Exchange Environment Through 2060

    NASA Technical Reports Server (NTRS)

    Roy, Aloke

    2015-01-01

    NASA's NextGen Concepts and Technology Development (CTD) Project focuses on capabilities to improve safety, capacity and efficiency of the National Air Space (NAS). In order to achieve those objectives, NASA sought industry-Government partnerships to research and identify solutions for traffic flow management, dynamic airspace configuration, separation assurance, super density operations, airport surface operations and similar forward-looking air-traffic modernization (ATM) concepts. Data exchanges over NAS being the key enabler for most of these ATM concepts, the Sub-Topic area 3 of the CTD project sought to identify technology candidates that can satisfy air-to-air and air/ground communications needs of the NAS in the year 2060 timeframe. Honeywell, under a two-year contract with NASA, is working on this communications technology research initiative. This report summarizes Honeywell's research conducted during the second year of the study task.

  7. Upgrades to the Probabilistic NAS Platform Air Traffic Simulation Software

    NASA Technical Reports Server (NTRS)

    Hunter, George; Boisvert, Benjamin

    2013-01-01

    This document is the final report for the project entitled "Upgrades to the Probabilistic NAS Platform Air Traffic Simulation Software." This report consists of 17 sections which document the results of the several subtasks of this effort. The Probabilistic NAS Platform (PNP) is an air operations simulation platform developed and maintained by the Saab Sensis Corporation. The improvements made to the PNP simulation include the following: an airborne distributed separation assurance capability, a required time of arrival assignment and conformance capability, and a tactical and strategic weather avoidance capability.

  8. Phthalates and Cumulative Risk Assessment (NAS Final Report)

    EPA Science Inventory

    Risk assessment has become a dominant public policy tool for making choices, based on limited resources, to protect public health and the environment. NAS_phthalates_cover.jpg" vspace = "5" hspace="5" align="left" border="1" alt="Cover ...

  9. UAS in the NAS Flight Test Series 3 Overview

    NASA Technical Reports Server (NTRS)

    Murphy, James R.

    2015-01-01

    The UAS Integration in the NAS Project is conducting a series of flight tests to acheive the following objectives: 1.) Validate results previously collected during project simulations with live data 2.) Evaluate TCAS IISS interoperability 3.) Test fully integrated system in a relevant live test environment 4.) Inform final DAA and C2 MOPS 5.) Reduce risk for Flight Test Series 4.

  10. Unstructured Adaptive (UA) NAS Parallel Benchmark. Version 1.0

    NASA Technical Reports Server (NTRS)

    Feng, Huiyu; VanderWijngaart, Rob; Biswas, Rupak; Mavriplis, Catherine

    2004-01-01

    We present a complete specification of a new benchmark for measuring the performance of modern computer systems when solving scientific problems featuring irregular, dynamic memory accesses. It complements the existing NAS Parallel Benchmark suite. The benchmark involves the solution of a stylized heat transfer problem in a cubic domain, discretized on an adaptively refined, unstructured mesh.

  11. The nasB operon and nasA gene are required for nitrate/nitrite assimilation in Bacillus subtilis.

    PubMed Central

    Ogawa, K; Akagawa, E; Yamane, K; Sun, Z W; LaCelle, M; Zuber, P; Nakano, M M

    1995-01-01

    Bacillus subtilis can use either nitrate or nitrite as a sole source of nitrogen. The isolation of the nasABCDEF genes of B. subtilis, which are required for nitrate/nitrite assimilation, is reported. The probable gene products include subunits of nitrate/nitrite reductases and an enzyme involved in the synthesis of siroheme, a cofactor for nitrite reductase. PMID:7868621

  12. Nitrogen regulation of nasA and the nasB operon, which encode genes required for nitrate assimilation in Bacillus subtilis.

    PubMed Central

    Nakano, M M; Yang, F; Hardin, P; Zuber, P

    1995-01-01

    The divergently transcribed nasA gene and nasB operon are required for nitrate and nitrite assimilation in Bacillus subtilis. The beta-galactosidase activity of transcriptional lacZ fusions from the nasA and nasB promoters was high when cells were grown in minimal glucose medium containing poor nitrogen sources such as nitrate, proline, or glutamate. The expression was very low when ammonium or glutamine was used as the sole nitrogen source. The repression of the genes during growth on good sources of nitrogen required wild-type glutamine synthetase (GlnA), but not GlnR, the repressor of the glnRA operon. Primer extension analysis showed that the -10 region of each promoter resembles those of sigma A-recognized promoters. Between the divergently oriented nasA and nasB promoters is a region of dyad symmetry. Mutational analysis led to the conclusion that this sequence is required in cis for the activation of both nasA and nasB. The derepression of these genes in a glnA mutant also required this sequence. These results suggest that an unidentified transcriptional activator and glutamine synthetase function in the regulation of nasA and the nasB operon. PMID:7836289

  13. Applications Performance on NAS Intel Paragon XP/S - 15#

    NASA Technical Reports Server (NTRS)

    Saini, Subhash; Simon, Horst D.; Copper, D. M. (Technical Monitor)

    1994-01-01

    The Numerical Aerodynamic Simulation (NAS) Systems Division received an Intel Touchstone Sigma prototype model Paragon XP/S- 15 in February, 1993. The i860 XP microprocessor with an integrated floating point unit and operating in dual -instruction mode gives peak performance of 75 million floating point operations (NIFLOPS) per second for 64 bit floating point arithmetic. It is used in the Paragon XP/S-15 which has been installed at NAS, NASA Ames Research Center. The NAS Paragon has 208 nodes and its peak performance is 15.6 GFLOPS. Here, we will report on early experience using the Paragon XP/S- 15. We have tested its performance using both kernels and applications of interest to NAS. We have measured the performance of BLAS 1, 2 and 3 both assembly-coded and Fortran coded on NAS Paragon XP/S- 15. Furthermore, we have investigated the performance of a single node one-dimensional FFT, a distributed two-dimensional FFT and a distributed three-dimensional FFT Finally, we measured the performance of NAS Parallel Benchmarks (NPB) on the Paragon and compare it with the performance obtained on other highly parallel machines, such as CM-5, CRAY T3D, IBM SP I, etc. In particular, we investigated the following issues, which can strongly affect the performance of the Paragon: a. Impact of the operating system: Intel currently uses as a default an operating system OSF/1 AD from the Open Software Foundation. The paging of Open Software Foundation (OSF) server at 22 MB to make more memory available for the application degrades the performance. We found that when the limit of 26 NIB per node out of 32 MB available is reached, the application is paged out of main memory using virtual memory. When the application starts paging, the performance is considerably reduced. We found that dynamic memory allocation can help applications performance under certain circumstances. b. Impact of data cache on the i860/XP: We measured the performance of the BLAS both assembly coded and Fortran

  14. NAS Grid Benchmarks: A Tool for Grid Space Exploration

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael; VanderWijngaart, Rob F.; Biegel, Bryan (Technical Monitor)

    2001-01-01

    We present an approach for benchmarking services provided by computational Grids. It is based on the NAS Parallel Benchmarks (NPB) and is called NAS Grid Benchmark (NGB) in this paper. We present NGB as a data flow graph encapsulating an instance of an NPB code in each graph node, which communicates with other nodes by sending/receiving initialization data. These nodes may be mapped to the same or different Grid machines. Like NPB, NGB will specify several different classes (problem sizes). NGB also specifies the generic Grid services sufficient for running the bench-mark. The implementor has the freedom to choose any specific Grid environment. However, we describe a reference implementation in Java, and present some scenarios for using NGB.

  15. Evaluating the Information Power Grid using the NAS Grid Benchmarks

    NASA Technical Reports Server (NTRS)

    VanderWijngaartm Rob F.; Frumkin, Michael A.

    2004-01-01

    The NAS Grid Benchmarks (NGB) are a collection of synthetic distributed applications designed to rate the performance and functionality of computational grids. We compare several implementations of the NGB to determine programmability and efficiency of NASA's Information Power Grid (IPG), whose services are mostly based on the Globus Toolkit. We report on the overheads involved in porting existing NGB reference implementations to the IPG. No changes were made to the component tasks of the NGB can still be improved.

  16. NASA UAS Integration into the NAS Project: Human Systems Integration

    NASA Technical Reports Server (NTRS)

    Shively, Jay

    2016-01-01

    This presentation provides an overview of the work the Human Systems Integration (HSI) sub-project has done on detect and avoid (DAA) displays while working on the UAS (Unmanned Aircraft System) Integration into the NAS project. The most recent simulation on DAA interoperability with Traffic Collision Avoidance System (TCAS) is discussed in the most detail. The relationship of the work to the larger UAS community and next steps are also detailed.

  17. Implementation of the NAS Parallel Benchmarks in Java

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael A.; Schultz, Matthew; Jin, Haoqiang; Yan, Jerry; Biegel, Bryan (Technical Monitor)

    2002-01-01

    Several features make Java an attractive choice for High Performance Computing (HPC). In order to gauge the applicability of Java to Computational Fluid Dynamics (CFD), we have implemented the NAS (NASA Advanced Supercomputing) Parallel Benchmarks in Java. The performance and scalability of the benchmarks point out the areas where improvement in Java compiler technology and in Java thread implementation would position Java closer to Fortran in the competition for CFD applications.

  18. Performance and Scalability of the NAS Parallel Benchmarks in Java

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael A.; Schultz, Matthew; Jin, Haoqiang; Yan, Jerry; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    Several features make Java an attractive choice for scientific applications. In order to gauge the applicability of Java to Computational Fluid Dynamics (CFD), we have implemented the NAS (NASA Advanced Supercomputing) Parallel Benchmarks in Java. The performance and scalability of the benchmarks point out the areas where improvement in Java compiler technology and in Java thread implementation would position Java closer to Fortran in the competition for scientific applications.

  19. Advanced Intermediate-Temperature Na-S Battery

    SciTech Connect

    Lu, Xiaochuan; Kirby, Brent W.; Xu, Wu; Li, Guosheng; Kim, Jin Yong; Lemmon, John P.; Sprenkle, Vincent L.; Yang, Zhenguo

    2012-11-12

    In this study, we reported an intermediate-temperature (~150°C) sodium-sulfur (Na-S) battery. With a reduced operating temperature, this novel battery can potentially reduce the cost and safety issues associated with the conventional high-temperature (300~350°C) Na-S battery. A dense β"-Al2O3 solid membrane and tetraglyme were utilized as the electrolyte separator and catholyte solvent in this battery. Solubility tests indicated that cathode mixture of Na2S4 and S exhibited extremely high solubility in tetraglyme (e.g., > 4.1 M for Na2S4 + 4 S). CV scans of Na2S4 in tetraglyme revealed two pairs of redox couples with peaks at around 2.22 and 1.75 V, corresponding to the redox reactions of polysulfide species. The discharge/charge profiles of the Na-S battery showed a slope region and a plateau, indicating multiple steps and cell reactions. In-situ Raman measurements during battery operation suggested that polysulfide species were formed in the sequence of Na2S5 + S → Na2S5 + Na2S4→ Na2S4 + Na2S2 during discharge and in a reverse order during charge. This battery showed dramatic improvement in rate capacity and cycling stability over room-temperature Na-S batteries, which makes it attractive for renewable energy integration and other grid related applications.

  20. 48 CFR 852.236-83 - Payments under fixed-price construction contracts (including NAS).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... construction contracts (including NAS). 852.236-83 Section 852.236-83 Federal Acquisition Regulations System... Provisions and Clauses 852.236-83 Payments under fixed-price construction contracts (including NAS). As... Analysis System (NAS).” Payments Under Fixed-Price Construction Contracts (JUL 2002) The clause...

  1. Graded band gap GaInNAs solar cells

    SciTech Connect

    Langer, F.; Perl, S.; Kamp, M.; Höfling, S.

    2015-06-08

    Dilute nitride GaInN(Sb)As with a band gap (E{sub g}) of 1.0 eV is a promising material for the integration in next generation multijunction solar cells. We have investigated the effect of a compositionally graded GaInNAs absorber layer on the spectral response of a GaInNAs sub cell. We produced band gap gradings (ΔE{sub g}) of up to 39 meV across a 1 μm thick GaInNAs layer. Thereby, the external quantum efficiency—compared to reference cells—was increased due to the improved extraction of photo-generated carriers from 34.0% to 36.7% for the wavelength range from 900 nm to 1150 nm. However, this device figure improvement is accompanied by a small decrease in the open circuit voltage of about 20 mV and the shift of the absorption edge to shorter wavelengths.

  2. Autotasked Performance in the NAS Workload: A Statistical Analysis

    NASA Technical Reports Server (NTRS)

    Carter, R. L.; Stockdale, I. E.; Kutler, Paul (Technical Monitor)

    1998-01-01

    A statistical analysis of the workload performance of a production quality FORTRAN code for five different Cray Y-MP hardware and system software configurations is performed. The analysis was based on an experimental procedure that was designed to minimize correlations between the number of requested CPUs and the time of day the runs were initiated. Observed autotasking over heads were significantly larger for the set of jobs that requested the maximum number of CPUs. Speedups for UNICOS 6 releases show consistent wall clock speedups in the workload of around 2. which is quite good. The observed speed ups were very similar for the set of jobs that requested 8 CPUs and the set that requested 4 CPUs. The original NAS algorithm for determining charges to the user discourages autotasking in the workload. A new charging algorithm to be applied to jobs run in the NQS multitasking queues also discourages NAS users from using auto tasking. The new algorithm favors jobs requesting 8 CPUs over those that request less, although the jobs requesting 8 CPUs experienced significantly higher over head and presumably degraded system throughput. A charging algorithm is presented that has the following desirable characteristics when applied to the data: higher overhead jobs requesting 8 CPUs are penalized when compared to moderate overhead jobs requesting 4 CPUs, thereby providing a charging incentive to NAS users to use autotasking in a manner that provides them with significantly improved turnaround while also maintaining system throughput.

  3. Study of GaInNAs Epilayers Using Optical Methods

    NASA Astrophysics Data System (ADS)

    Tsai, Yutsung

    Photovoltaic devices that convert sun's energy into electricity have the potential to influence energy needs on a global scale. A major limitation of single junction solar cells is that only photons with energy slightly above the bandgap are absorbed efficiently. One of the methods is to split the energy of the incoming spectrum into multiple bands each of which is absorbed separately for more efficient collection. That is why multijunction solar cells formed from III-V compound semiconductors are the highest efficiency photovoltaic devices today. To achieve this goal, researchers stack a number of junctions made of different materials with the highest gap material at the top and the lowest at the bottom since each material is transparent to photons with energy smaller than its bandgap. Kurtz [1] predicted an improvement in the performance of multijunction solar cells if a fourth material with bandgap in the 1.0eV-1.05eV range is included between the GaAs (bandgap = 1.42 eV) and Ge (bandgap = 0.67 eV) in the solar cell. In order for this fourth material to be easily incorporated into the GaInP/ GaAs/Ge triple junction device, it must also be lattice matched to germanium. Since it is preferred to grow multijunction solar cells monolithically lattice matching is required making the options for the 1 eV material rather limited. The most promising material for the fourth junction is currently GaInNAs. This is the reason why this thesis concentrates on the study of this material. In this thesis, we have conducted PL, optical pumping, magneto-PL, reflectance and transmission spectroscopic studies of undoped and p-type doped GaInNAs epilayers. The objective of these studies is to investigate the following phenomena in our samples: (a) Localized excitons and free excitons at low temperatures in GaInNAs epilayers: The exciton localization at low temperatures in undoped GaInNAs epilayers results in the S-shape of the PL peaks versus temperature plot. On the other hand, the

  4. Hybrid Network Architectures for the Next Generation NAS

    NASA Technical Reports Server (NTRS)

    Madubata, Christian

    2003-01-01

    To meet the needs of the 21st Century NAS, an integrated, network-centric infrastructure is essential that is characterized by secure, high bandwidth, digital communication systems that support precision navigation capable of reducing position errors for all aircraft to within a few meters. This system will also require precision surveillance systems capable of accurately locating all aircraft, and automatically detecting any deviations from an approved path within seconds and be able to deliver high resolution weather forecasts - critical to create 4- dimensional (space and time) profiles for up to 6 hours for all atmospheric conditions affecting aviation, including wake vortices. The 21st Century NAS will be characterized by highly accurate digital data bases depicting terrain, obstacle, and airport information no matter what visibility conditions exist. This research task will be to perform a high-level requirements analysis of the applications, information and services required by the next generation National Airspace System. The investigation and analysis is expected to lead to the development and design of several national network-centric communications architectures that would be capable of supporting the Next Generation NAS.

  5. Aquisição de Estreptococos Mutans e Desenvolvimento de Cárie Dental em Primogênitos

    PubMed Central

    NOCE, Erica; RUBIRA, Cassia Maria Fischer; da Silva ROSA, Odila Pereira; da SILVA, Salete Moura Bonifácio; BRETZ, Walter Antonio

    2011-01-01

    Objetivo Avaliar o momento de aquisição de estreptococos mutans (EM), desenvolvimento de cárie dental e as variáveis a eles associadas no decorrer de 23 meses, em primogênitos de famílias de baixo nível socioeconômico, desde os sete meses de idade. Método A amostra foi selecionada com base em mães densamente colonizadas por EM, incluindo todos os membros de 14 famílias que conviviam na mesma casa. Foram envolvidos no estudo 14 mães, pais e primogênitos e 8 parentes, na maioria avós. Exames clínicos e radiográficos iniciais determinaram os índices de cárie e condição periodontal dos adultos. Contagens de EM foram feitas em todos os adultos nas duas primeiras visitas. Nas crianças foram avaliados os níveis de EM, o número de dentes e de cáries, em quatro visitas. Resultados A prevalência de EM nos adultos foi alta, estando ausente em apenas um dos pais. EM foram detectados em 1, 2, 3 e 10 crianças, respectivamente nas visitas #1, 2, 3 e 4. A cárie dental foi detectada em apenas três crianças na última visita (aos 30 meses de idade), as quais apresentaram escores de EM significantemente maiores que as crianças sem cárie, na mesma visita. Conclusão Exclusivamente a condição social de baixa renda e mães densamente colonizadas por EM não são sinônimo de colonização precoce e alta atividade de cárie em crianças cuidadas em casa. O desenvolvimento de cárie está significantemente associado a escores elevados de EM nas crianças. PMID:22022218

  6. High electron mobility in Ga(In)NAs films grown by molecular beam epitaxy

    SciTech Connect

    Miyashita, Naoya; Ahsan, Nazmul; Monirul Islam, Muhammad; Okada, Yoshitaka; Inagaki, Makoto; Yamaguchi, Masafumi

    2012-11-26

    We report the highest mobility values above 2000 cm{sup 2}/Vs in Si doped GaNAs film grown by molecular beam epitaxy. To understand the feature of the origin which limits the electron mobility in GaNAs, temperature dependences of mobility were measured for high mobility GaNAs and referential low mobility GaInNAs. Temperature dependent mobility for high mobility GaNAs is similar to the GaAs case, while that for low mobility GaInNAs shows large decrease in lower temperature region. The electron mobility of high quality GaNAs can be explained by intrinsic limiting factor of random alloy scattering and extrinsic factor of ionized impurity scattering.

  7. NAS Requirements Checklist for Job Queuing/Scheduling Software

    NASA Technical Reports Server (NTRS)

    Jones, James Patton

    1996-01-01

    The increasing reliability of parallel systems and clusters of computers has resulted in these systems becoming more attractive for true production workloads. Today, the primary obstacle to production use of clusters of computers is the lack of a functional and robust Job Management System for parallel applications. This document provides a checklist of NAS requirements for job queuing and scheduling in order to make most efficient use of parallel systems and clusters for parallel applications. Future requirements are also identified to assist software vendors with design planning.

  8. Navigation in Grid Space with the NAS Grid Benchmarks

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael; Hood, Robert; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    We present a navigational tool for computational grids. The navigational process is based on measuring the grid characteristics with the NAS Grid Benchmarks (NGB) and using the measurements to assign tasks of a grid application to the grid machines. The tool allows the user to explore the grid space and to navigate the execution at a grid application to minimize its turnaround time. We introduce the notion of gridscape as a user view of the grid and show how it can be me assured by NGB, Then we demonstrate how the gridscape can be used with two different schedulers to navigate a grid application through a rudimentary grid.

  9. Parallelization of NAS Benchmarks for Shared Memory Multiprocessors

    NASA Technical Reports Server (NTRS)

    Waheed, Abdul; Yan, Jerry C.; Saini, Subhash (Technical Monitor)

    1998-01-01

    This paper presents our experiences of parallelizing the sequential implementation of NAS benchmarks using compiler directives on SGI Origin2000 distributed shared memory (DSM) system. Porting existing applications to new high performance parallel and distributed computing platforms is a challenging task. Ideally, a user develops a sequential version of the application, leaving the task of porting to new generations of high performance computing systems to parallelization tools and compilers. Due to the simplicity of programming shared-memory multiprocessors, compiler developers have provided various facilities to allow the users to exploit parallelism. Native compilers on SGI Origin2000 support multiprocessing directives to allow users to exploit loop-level parallelism in their programs. Additionally, supporting tools can accomplish this process automatically and present the results of parallelization to the users. We experimented with these compiler directives and supporting tools by parallelizing sequential implementation of NAS benchmarks. Results reported in this paper indicate that with minimal effort, the performance gain is comparable with the hand-parallelized, carefully optimized, message-passing implementations of the same benchmarks.

  10. UAS-NAS Project Demo - Mini HITL Week 2 Stats

    NASA Technical Reports Server (NTRS)

    Murphy, James R.; Fern, Lisa C.; Rorie, Robert C.; Shively, Robert; Jovic, Srboljub

    2016-01-01

    The UAS-NAS Project demo will showcase recent research efforts to ensure the interoperability between proposed UAS detect and avoid (DAA) human machine interface requirements (developed within RTCA SC-228) and existing collision avoidance displays. Attendees will be able to view the current state of the art of the DAA pilot traffic, alerting and guidance displays integrated with Traffic advisory and Collision Avoidance (TCAS) II in the UAS-NAS Project's research UAS ground control station (developed in partnership with the Air Force Research Laboratory). In addition, attendees will have the opportunity to interact with the research UAS ground control station and "fly" encounters, using the DAA and TCAS II displays to avoid simulated aircraft. The display of the advisories will be hosted on a laptop with an external 30" monitor, running the Vigilant Spirit system. DAA advisories will be generated by the JADEM software tool, connected to the system via the LVC Gateway. A repeater of the primary flight display will be shown on a 55" monitor mounted on a stand at the back of the booth to show the pilot interaction to the passersby.

  11. Concepts of Integration for UAS Operations in the NAS

    NASA Technical Reports Server (NTRS)

    Consiglio, Maria C.; Chamberlain, James P.; Munoz, Cesar A.; Hoffler, Keith D.

    2012-01-01

    One of the major challenges facing the integration of Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) is the lack of an onboard pilot that can comply with the legal requirement identified in the US Code of Federal Regulations (CFR) that pilots see and avoid other aircraft. UAS will be expected to demonstrate the means to perform the function of see and avoid while preserving the safety level of the airspace and the efficiency of the air traffic system. This paper introduces a Sense and Avoid (SAA) concept for integration of UAS into the NAS that is currently being developed by the National Aeronautics and Space Administration (NASA) and identifies areas that require additional experimental evaluation to further inform various elements of the concept. The concept design rests on interoperability principles that take into account both the Air Traffic Control (ATC) environment as well as existing systems such as the Traffic Alert and Collision Avoidance System (TCAS). Specifically, the concept addresses the determination of well clear values that are large enough to avoid issuance of TCAS corrective Resolution Advisories, undue concern by pilots of proximate aircraft and issuance of controller traffic alerts. The concept also addresses appropriate declaration times for projected losses of well clear conditions and maneuvers to regain well clear separation.

  12. Data communication requirements for the advanced NAS network

    NASA Technical Reports Server (NTRS)

    Levin, Eugene; Eaton, C. K.; Young, Bruce

    1986-01-01

    The goal of the Numerical Aerodynamic Simulation (NAS) Program is to provide a powerful computational environment for advanced research and development in aeronautics and related disciplines. The present NAS system consists of a Cray 2 supercomputer connected by a data network to a large mass storage system, to sophisticated local graphics workstations, and by remote communications to researchers throughout the United States. The program plan is to continue acquiring the most powerful supercomputers as they become available. In the 1987/1988 time period it is anticipated that a computer with 4 times the processing speed of a Cray 2 will be obtained and by 1990 an additional supercomputer with 16 times the speed of the Cray 2. The implications of this 20-fold increase in processing power on the data communications requirements are described. The analysis was based on models of the projected workload and system architecture. The results are presented together with the estimates of their sensitivity to assumptions inherent in the models.

  13. 1.15 Å resolution structure of the proteasome-assembly chaperone Nas2 PDZ domain

    SciTech Connect

    Singh, Chingakham R.; Lovell, Scott; Mehzabeen, Nurjahan; Chowdhury, Wasimul Q.; Geanes, Eric S.; Battaile, Kevin P.; Roelofs, Jeroen

    2014-03-25

    The proteasome-assembly chaperone Nas2 binds to the proteasome subunit Rpt5 using its PDZ domain. The structure of the Nas2 PDZ domain has been determined. The 26S proteasome is a 2.5 MDa protease dedicated to the degradation of ubiquitinated proteins in eukaryotes. The assembly of this complex containing 66 polypeptides is assisted by at least nine proteasome-specific chaperones. One of these, Nas2, binds to the proteasomal AAA-ATPase subunit Rpt5. The PDZ domain of Nas2 binds to the C-terminal tail of Rpt5; however, it does not require the C-terminus of Rpt5 for binding. Here, the 1.15 Å resolution structure of the PDZ domain of Nas2 is reported. This structure will provide a basis for further insights regarding the structure and function of Nas2 in proteasome assembly.

  14. nasST, two genes involved in the induction of the assimilatory nitrite-nitrate reductase operon (nasAB) of Azotobacter vinelandii.

    PubMed

    Gutierrez, J C; Ramos, F; Ortner, L; Tortolero, M

    1995-11-01

    An operon including two new genes (nasS and nasT) has been defined, cloned and sequenced. The deduced NASS protein is homologous to NRTA from Synechococcus sp. and to NASF from Klebsiella pneumoniae, two proteins involved in nitrate uptake. The predicted NAST polypeptide is homologous to the regulator proteins of the two-component regulatory systems. NASS plays a negative regulatory role in the synthesis of the nitrate and nitrite reductase. NAST is required for the expression of the nitrite-nitrate reductase operon (nasAB). Expression of the nasST operon is not under the control of the NTR system and is not regulated by the nitrogen source. A Phi(nasA-lacZ) fusion has been used to analyse expression of the nasAB operon in three different genetic backgrounds with altered nitrate reductase activity. Beta-galactosidase activity in two of them was independent of nitrate but in a mutant unable to reduce nitrate, nas-4, it was normally induced by nitrate. PMID:8748040

  15. The nasFEDCBA operon for nitrate and nitrite assimilation in Klebsiella pneumoniae M5al.

    PubMed

    Lin, J T; Goldman, B S; Stewart, V

    1994-05-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources through the nitrate assimilation pathway. We previously identified structural genes for assimilatory nitrate and nitrite reductases, nasA and nasB, respectively. We report here our further identification of four genes, nasFEDC, upstream of the nasBA genes. The nasFEDCBA genes probably form an operon. Mutational and complementation analyses indicated that both the nasC and nasA genes are required for nitrate assimilation. The predicted NASC protein is homologous to a variety of NADH-dependent oxidoreductases. Thus, the NASC protein probably mediates electron transfer from NADH to the NASA protein, which contains the active site for nitrate reduction. The deduced NASF, NASE, and NASD proteins are homologous to the NRTA, NRTB, and NRTD proteins, respectively, that are involved in nitrate uptake in Synechococcus sp. (T. Omata, X. Andriesse, and A. Hirano, Mol. Gen. Genet. 236:193-202, 1993). Mutational and complementation studies indicated that the nasD gene is required for nitrate but not nitrite assimilation. By analogy with the Synechococcus nrt genes, we propose that the nasFED genes are involved in nitrate transport in K. pneumoniae. PMID:8169203

  16. The nasFEDCBA operon for nitrate and nitrite assimilation in Klebsiella pneumoniae M5al.

    PubMed Central

    Lin, J T; Goldman, B S; Stewart, V

    1994-01-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources through the nitrate assimilation pathway. We previously identified structural genes for assimilatory nitrate and nitrite reductases, nasA and nasB, respectively. We report here our further identification of four genes, nasFEDC, upstream of the nasBA genes. The nasFEDCBA genes probably form an operon. Mutational and complementation analyses indicated that both the nasC and nasA genes are required for nitrate assimilation. The predicted NASC protein is homologous to a variety of NADH-dependent oxidoreductases. Thus, the NASC protein probably mediates electron transfer from NADH to the NASA protein, which contains the active site for nitrate reduction. The deduced NASF, NASE, and NASD proteins are homologous to the NRTA, NRTB, and NRTD proteins, respectively, that are involved in nitrate uptake in Synechococcus sp. (T. Omata, X. Andriesse, and A. Hirano, Mol. Gen. Genet. 236:193-202, 1993). Mutational and complementation studies indicated that the nasD gene is required for nitrate but not nitrite assimilation. By analogy with the Synechococcus nrt genes, we propose that the nasFED genes are involved in nitrate transport in K. pneumoniae. PMID:8169203

  17. An improved NAS-RIF algorithm for blind image restoration

    NASA Astrophysics Data System (ADS)

    Liu, Ning; Jiang, Yanbin; Lou, Shuntian

    2007-01-01

    Image restoration is widely applied in many areas, but when operating on images with different scales for the representation of pixel intensity levels or low SNR, the traditional restoration algorithm lacks validity and induces noise amplification, ringing artifacts and poor convergent ability. In this paper, an improved NAS-RIF algorithm is proposed to overcome the shortcomings of the traditional algorithm. The improved algorithm proposes a new cost function which adds a space-adaptive regularization term and a disunity gain of the adaptive filter. In determining the support region, a pre-segmentation is used to form it close to the object in the image. Compared with the traditional algorithm, simulations show that the improved algorithm behaves better convergence, noise resistance and provides a better estimate of original image.

  18. NAS Miramar Molten Carbonate Fuel Cell demonstration status

    SciTech Connect

    Scroppo, J.A.

    1996-12-31

    Part of M-C Power`s Technology Development Program, this MCFC power plant is designed to supply 250 kW of electricity to Naval Air Station (NAS) Miramar. It also cogenerates steam for the district heating system. The power plant is a fully integrated unit incorporating an advanced design fuel cell based on years of laboratory tests and a prior field test. This demonstration incorporates many innovative features, one of which is the plate type reformer which processes the natural gas fuel for use in the fuel cell. M-C Power Corp. has completed the design, fabrication, and conditioning of a 250-cell fuel cell stack, which was shipped to the site where it will be installed, tested, and evaluated as a 250 kW Proof-of-Concept MCFC Power Plant. (Originally going to Kaiser Permanente`s Sand Diego Medical Center, it was relocated to Miramar.)

  19. Remotely Operated Aircraft (ROA) Impact on the National Airspace System (NAS) Work Package: Automation Impacts of ROA's in the NAS

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The purpose of this document is to analyze the impact of Remotely Operated Aircraft (ROA) operations on current and planned Air Traffic Control (ATC) automation systems in the En Route, Terminal, and Traffic Flow Management domains. The operational aspects of ROA flight, while similar, are not entirely identical to their manned counterparts and may not have been considered within the time-horizons of the automation tools. This analysis was performed to determine if flight characteristics of ROAs would be compatible with current and future NAS automation tools. Improvements to existing systems / processes are recommended that would give Air Traffic Controllers an indication that a particular aircraft is an ROA and modifications to IFR flight plan processing algorithms and / or designation of airspace where an ROA will be operating for long periods of time.

  20. Looking Backward: Parting Reflections on Higher Education Reform from NAS's Founding President

    ERIC Educational Resources Information Center

    Balch, Stephen H.

    2012-01-01

    Twenty-five years at the helm of the National Association of Scholars (NAS) have left the author with vivid memories: of knocks and bruises, peaks of exhilaration and, especially, unforgettable characters. But as for lessons learned, that's a very different story. In this article, the author shares some of the successes that happened in NAS for…

  1. Genome-wide identification, classification and expression profiling of nicotianamine synthase (NAS) gene family in maize

    PubMed Central

    2013-01-01

    Background Nicotianamine (NA), a ubiquitous molecule in plants, is an important metal ion chelator and the main precursor for phytosiderophores biosynthesis. Considerable progress has been achieved in cloning and characterizing the functions of nicotianamine synthase (NAS) in plants including barley, Arabidopsis and rice. Maize is not only an important cereal crop, but also a model plant for genetics and evolutionary study. The genome sequencing of maize was completed, and many gene families were identified. Although three NAS genes have been characterized in maize, there is still no systematic identification of maize NAS family by genomic mining. Results In this study, nine NAS genes in maize were identified and their expression patterns in different organs including developing seeds were determined. According to the evolutionary relationship and tissue specific expression profiles of ZmNAS genes, they can be subgrouped into two classes. Moreover, the expression patterns of ZmNAS genes in response to fluctuating metal status were analysed. The class I ZmNAS genes were induced under Fe deficiency and were suppressed under Fe excessive conditions, while the expression pattern of class II genes were opposite to class I. The complementary expression patterns of class I and class II ZmNAS genes confirmed the classification of this family. Furthermore, the histochemical localization of ZmNAS1;1/1;2 and ZmNAS3 were determined using in situ hybridization. It was revealed that ZmNAS1;1/1;2, representing the class I genes, mainly expressed in cortex and stele of roots with sufficient Fe, and its expression can expanded in epidermis, as well as shoot apices under Fe deficient conditions. On the contrary, ZmNAS3, one of the class II genes, was accumulated in axillary meristems, leaf primordia and mesophyll cells. These results suggest that the two classes of ZmNAS genes may be regulated on transcriptional level when responds to various demands for iron uptake, translocation

  2. Natural Attenuation Software (NAS): A computer program for estimating remediation times of contaminated groundwater

    USGS Publications Warehouse

    Mendez, E.; Widdowson, M.; Brauner, S.; Chapelle, F.; Casey, C.

    2004-01-01

    This paper describes the development and application of a modeling system called Natural Attenuation Software (NAS). NAS was designed as a screening tool to estimate times of remediation (TORs), associated with monitored natural attenuation (MNA), to lower groundwater contaminant concentrations to regulatory limits. Natural attenuation processes that NAS models include advection, dispersion, sorption, biodegradation, and non-aqueous phase liquid (NAPL) dissolution. This paper discusses the three main interactive components of NAS: 1) estimation of the target source concentration required for a plume extent to contract to regulatory limits, 2) estimation of the time required for NAFL contaminants in the source area to attenuate to a predetermined target source concentration, and 3) estimation of the time required for a plume extent to contract to regulatory limits after source reduction. The model's capability is illustrated by results from a case study at a MNA site, where NAS time of remediation estimates compared well with observed monitoring data over multiple years.

  3. NasFED proteins mediate assimilatory nitrate and nitrite transport in Klebsiella oxytoca (pneumoniae) M5al.

    PubMed

    Wu, Q; Stewart, V

    1998-03-01

    Klebsiella oxytoca can use nitrate and nitrite as sole nitrogen sources. The enzymes required for nitrate and nitrite assimilation are encoded by the nasFEDCBA operon. We report here the complete nasFED sequence. Sequence comparisons indicate that the nasFED genes encode components of a conventional periplasmic binding protein-dependent transport system consisting of a periplasmic binding protein (NasF), a homodimeric intrinsic membrane protein (NasE), and a homodimeric ATP-binding cassette (ABC) protein (NasD). The NasF protein and the related NrtA and CmpA proteins of cyanobacteria contain leader (signal) sequences with the double-arginine motif that is hypothesized to direct prefolded proteins to an alternate protein export pathway. The NasE protein and the related NrtB and CmpB proteins of cyanobacteria contain unusual variants of the EAA loop sequence that defines membrane-intrinsic proteins of ABC transporters. To characterize nitrate and nitrite transport, we constructed in-frame nonpolar deletions of the chromosomal nasFED genes. Growth tests coupled with nitrate and nitrite uptake assays revealed that the nasFED genes are essential for nitrate transport and participate in nitrite transport as well. Interestingly, the delta nasF strain exhibited leaky phenotypes, particularly at elevated nitrate concentrations, suggesting that the NasED proteins are not fully dependent on the NasF protein. PMID:9495773

  4. NasFED Proteins Mediate Assimilatory Nitrate and Nitrite Transport in Klebsiella oxytoca (pneumoniae) M5al

    PubMed Central

    Wu, Qitu; Stewart, Valley

    1998-01-01

    Klebsiella oxytoca can use nitrate and nitrite as sole nitrogen sources. The enzymes required for nitrate and nitrite assimilation are encoded by the nasFEDCBA operon. We report here the complete nasFED sequence. Sequence comparisons indicate that the nasFED genes encode components of a conventional periplasmic binding protein-dependent transport system consisting of a periplasmic binding protein (NasF), a homodimeric intrinsic membrane protein (NasE), and a homodimeric ATP-binding cassette (ABC) protein (NasD). The NasF protein and the related NrtA and CmpA proteins of cyanobacteria contain leader (signal) sequences with the double-arginine motif that is hypothesized to direct prefolded proteins to an alternate protein export pathway. The NasE protein and the related NrtB and CmpB proteins of cyanobacteria contain unusual variants of the EAA loop sequence that defines membrane-intrinsic proteins of ABC transporters. To characterize nitrate and nitrite transport, we constructed in-frame nonpolar deletions of the chromosomal nasFED genes. Growth tests coupled with nitrate and nitrite uptake assays revealed that the nasFED genes are essential for nitrate transport and participate in nitrite transport as well. Interestingly, the ΔnasF strain exhibited leaky phenotypes, particularly at elevated nitrate concentrations, suggesting that the NasED proteins are not fully dependent on the NasF protein. PMID:9495773

  5. Performance Characteristics of the Multi-Zone NAS Parallel Benchmarks

    NASA Technical Reports Server (NTRS)

    Jin, Haoqiang; VanderWijngaart, Rob F.

    2003-01-01

    We describe a new suite of computational benchmarks that models applications featuring multiple levels of parallelism. Such parallelism is often available in realistic flow computations on systems of grids, but had not previously been captured in bench-marks. The new suite, named NPB Multi-Zone, is extended from the NAS Parallel Benchmarks suite, and involves solving the application benchmarks LU, BT and SP on collections of loosely coupled discretization meshes. The solutions on the meshes are updated independently, but after each time step they exchange boundary value information. This strategy provides relatively easily exploitable coarse-grain parallelism between meshes. Three reference implementations are available: one serial, one hybrid using the Message Passing Interface (MPI) and OpenMP, and another hybrid using a shared memory multi-level programming model (SMP+OpenMP). We examine the effectiveness of hybrid parallelization paradigms in these implementations on three different parallel computers. We also use an empirical formula to investigate the performance characteristics of the multi-zone benchmarks.

  6. Performance Comparison of HPF and MPI Based NAS Parallel Benchmarks

    NASA Technical Reports Server (NTRS)

    Saini, Subhash

    1997-01-01

    Compilers supporting High Performance Form (HPF) features first appeared in late 1994 and early 1995 from Applied Parallel Research (APR), Digital Equipment Corporation, and The Portland Group (PGI). IBM introduced an HPF compiler for the IBM RS/6000 SP2 in April of 1996. Over the past two years, these implementations have shown steady improvement in terms of both features and performance. The performance of various hardware/ programming model (HPF and MPI) combinations will be compared, based on latest NAS Parallel Benchmark results, thus providing a cross-machine and cross-model comparison. Specifically, HPF based NPB results will be compared with MPI based NPB results to provide perspective on performance currently obtainable using HPF versus MPI or versus hand-tuned implementations such as those supplied by the hardware vendors. In addition, we would also present NPB, (Version 1.0) performance results for the following systems: DEC Alpha Server 8400 5/440, Fujitsu CAPP Series (VX, VPP300, and VPP700), HP/Convex Exemplar SPP2000, IBM RS/6000 SP P2SC node (120 MHz), NEC SX-4/32, SGI/CRAY T3E, and SGI Origin2000. We would also present sustained performance per dollar for Class B LU, SP and BT benchmarks.

  7. A Programming Model Performance Study Using the NAS Parallel Benchmarks

    DOE PAGESBeta

    Shan, Hongzhang; Blagojević, Filip; Min, Seung-Jai; Hargrove, Paul; Jin, Haoqiang; Fuerlinger, Karl; Koniges, Alice; Wright, Nicholas J.

    2010-01-01

    Harnessing the power of multicore platforms is challenging due to the additional levels of parallelism present. In this paper we use the NAS Parallel Benchmarks to study three programming models, MPI, OpenMP and PGAS to understand their performance and memory usage characteristics on current multicore architectures. To understand these characteristics we use the Integrated Performance Monitoring tool and other ways to measure communication versus computation time, as well as the fraction of the run time spent in OpenMP. The benchmarks are run on two different Cray XT5 systems and an Infiniband cluster. Our results show that in general the threemore » programming models exhibit very similar performance characteristics. In a few cases, OpenMP is significantly faster because it explicitly avoids communication. For these particular cases, we were able to re-write the UPC versions and achieve equal performance to OpenMP. Using OpenMP was also the most advantageous in terms of memory usage. Also we compare performance differences between the two Cray systems, which have quad-core and hex-core processors. We show that at scale the performance is almost always slower on the hex-core system because of increased contention for network resources.« less

  8. NAS Parallel Benchmark Results 11-96. 1.0

    NASA Technical Reports Server (NTRS)

    Bailey, David H.; Bailey, David; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    The NAS Parallel Benchmarks have been developed at NASA Ames Research Center to study the performance of parallel supercomputers. The eight benchmark problems are specified in a "pencil and paper" fashion. In other words, the complete details of the problem to be solved are given in a technical document, and except for a few restrictions, benchmarkers are free to select the language constructs and implementation techniques best suited for a particular system. These results represent the best results that have been reported to us by the vendors for the specific 3 systems listed. In this report, we present new NPB (Version 1.0) performance results for the following systems: DEC Alpha Server 8400 5/440, Fujitsu VPP Series (VX, VPP300, and VPP700), HP/Convex Exemplar SPP2000, IBM RS/6000 SP P2SC node (120 MHz), NEC SX-4/32, SGI/CRAY T3E, SGI Origin200, and SGI Origin2000. We also report High Performance Fortran (HPF) based NPB results for IBM SP2 Wide Nodes, HP/Convex Exemplar SPP2000, and SGI/CRAY T3D. These results have been submitted by Applied Parallel Research (APR) and Portland Group Inc. (PGI). We also present sustained performance per dollar for Class B LU, SP and BT benchmarks.

  9. Performance Analysis of the NAS Y-MP Workload

    NASA Technical Reports Server (NTRS)

    Bergeron, Robert J.; Kutler, Paul (Technical Monitor)

    1997-01-01

    This paper describes the performance characteristics of the computational workloads on the NAS Cray Y-MP machines, a Y-MP 832 and later a Y-MP 8128. Hardware measurements indicated that the Y-MP workload performance matured over time, ultimately sustaining an average throughput of 0.8 GFLOPS and a vector operation fraction of 87%. The measurements also revealed an operation rate exceeding 1 per clock period, a well-balanced architecture featuring a strong utilization of vector functional units, and an efficient memory organization. Introduction of the larger memory 8128 increased throughput by allowing a more efficient utilization of CPUs. Throughput also depended on the metering of the batch queues; low-idle Saturday workloads required a buffer of small jobs to prevent memory starvation of the CPU. UNICOS required about 7% of total CPU time to service the 832 workloads; this overhead decreased to 5% for the 8128 workloads. While most of the system time went to service I/O requests, efficient scheduling prevented excessive idle due to I/O wait. System measurements disclosed no obvious bottlenecks in the response of the machine and UNICOS to the workloads. In most cases, Cray-provided software tools were- quite sufficient for measuring the performance of both the machine and operating, system.

  10. Investigation of Deep Levels in GaInNas

    SciTech Connect

    Abulfotuh, F.; Balcioglu, A.; Friedman, D.; Geisz, J.; Kurtz, S.

    1998-11-12

    This paper presents and discusses the first Deep-Level transient spectroscopy (DLTS) data obtained from measurements carried out on both Schottky barriers and homojunction devices of GaInNAs. The effect of N and In doping on the electrical properties of the GaNInAs devices, which results in structural defects and interface states, has been investigated. Moreover, the location and densities of deep levels related to the presence of N, In, and N+In are identified and correlated with the device performance. The data confirmed that the presence of N alone creates a high density of shallow hole traps related to the N atom and structural defects in the device. Doping by In, if present alone, also creates low-density deep traps (related to the In atom and structural defects) and extremely deep interface states. On the other hand, the co-presence of In and N eliminates both the interface states and levels related to structural defects. However, the device still has a high density of the shallow and deep traps that are responsible for the photocurrent loss in the GaNInAs device, together with the possible short diffusion length.

  11. [Study on the Application of NAS-Based Algorithm in the NIR Model Optimization].

    PubMed

    Geng, Ying; Xiang, Bing-ren; He, Lan

    2015-10-01

    In this paper, net analysis signal (NAS)-based concept was introduced to the analysis of multi-component Ginkgo biloba leaf extracts. NAS algorithm was utilized for the preprocessing of spectra, and NAS-based two-dimensional correlation analysis was used for the optimization of NIR model building. Simultaneous quantitative models for three flavonol aglycones: quercetin, keampferol and isorhamnetin were established respectively. The NAS vectors calculated using two algorithms introduced from Lorber and Goicoechea and Olivieri (HLA/GO) were applied in the development of calibration models, the reconstructed spectra were used as input of PLS modeling. For the first time, NAS-based two-dimensional correlation spectroscopy was used for wave number selection. The regions appeared in the main diagonal were selected as useful regions for model building. The results implied that two NAS-based preprocessing methods were successfully used for the analysis of quercetin, keampferol and isorhamnetin with a decrease of factor number and an improvement of model robustness. NAS-based algorithm was proven to be a useful tool for the preprocessing of spectra and for optimization of model calibration. The above research showed a practical application value for the NIRS in the analysis of complex multi-component petrochemical medicine with unknown interference. PMID:26904808

  12. Determination of composition of non-homogeneous GaInNAs layers

    NASA Astrophysics Data System (ADS)

    Pucicki, D.; Bielak, K.; Ściana, B.; Radziewicz, D.; Latkowska-Baranowska, M.; Kováč, J.; Vincze, A.; Tłaczała, M.

    2016-01-01

    Dilute nitride GaInNAs alloys grown on GaAs have become perspective materials for so called low-cost GaAs-based devices working within the optical wavelength range up to 1.6 μm. The multilayer structures of GaInNAs/GaAs multi-quantum well (MQW) samples usually are analyzed by using high resolution X-ray diffraction (HRXRD) measurements. However, demands for precise structural characterization of the GaInNAs containing heterostructures requires taking into consideration all inhomogeneities of such structures. This paper describes some of the material challenges and progress in structural characterization of GaInNAs layers. A new algorithm for structural characterization of dilute nitrides which bounds contactless electro-reflectance (CER) or photo-reflectance (PR) measurements and HRXRD analysis results together with GaInNAs quantum well band diagram calculation is presented. The triple quantum well (3QW) GaInNAs/GaAs structures grown by atmospheric-pressure metalorganic vapor-phase epitaxy (AP-MOVPE) were investigated according to the proposed algorithm. Thanks to presented algorithm, more precise structural data including the nonuniformity in the growth direction of GaInNAs/GaAs QWs were achieved. Therefore, the proposed algorithm is mentioned as a nondestructive method for characterization of multicomponent inhomogeneous semiconductor structures with quantum wells.

  13. The nitrate-sensing NasST system regulates nitrous oxide reductase and periplasmic nitrate reductase in Bradyrhizobium japonicum.

    PubMed

    Sánchez, Cristina; Itakura, Manabu; Okubo, Takashi; Matsumoto, Takashi; Yoshikawa, Hirofumi; Gotoh, Aina; Hidaka, Masafumi; Uchida, Takafumi; Minamisawa, Kiwamu

    2014-10-01

    The soybean endosymbiont Bradyrhizobium japonicum is able to scavenge the greenhouse gas N2O through the N2O reductase (Nos). In previous research, N2O emission from soybean rhizosphere was mitigated by B. japonicum Nos(++) strains (mutants with increased Nos activity). Here, we report the mechanism underlying the Nos(++) phenotype. Comparative analysis of Nos(++) mutant genomes showed that mutation of bll4572 resulted in Nos(++) phenotype. bll4572 encodes NasS, the nitrate (NO3(-))-sensor of the two-component NasST regulatory system. Transcriptional analyses of nosZ (encoding Nos) and other genes from the denitrification process in nasS and nasST mutants showed that, in the absence of NO3(-) , nasS mutation induces nosZ and nap (periplasmic nitrate reductase) via nasT. NO3(-) addition dissociated the NasS-NasT complex in vitro, suggesting the release of the activator NasT. Disruption of nasT led to a marked decrease in nosZ and nap transcription in cells incubated in the presence of NO3(-). Thus, although NasST is known to regulate the NO3(-)-mediated response of NO3(-) assimilation genes in bacteria, our results show that NasST regulates the NO3(-) -mediated response of nosZ and napE genes, from the dissimilatory denitrification pathway, in B. japonicum. PMID:24947409

  14. 78 FR 12951 - TRICARE; Elimination of the Non-Availability Statement (NAS) Requirement for Non-Emergency...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-26

    ... (NAS) Requirement for Non-Emergency Inpatient Mental Health Care AGENCY: Office of the Secretary... NAS is needed for non-emergency inpatient mental health care in order for a TRICARE Standard beneficiary's claim to be paid. Currently, NAS are required for non-emergency inpatient mental health care...

  15. Identification and structure of the nasR gene encoding a nitrate- and nitrite-responsive positive regulator of nasFEDCBA (nitrate assimilation) operon expression in Klebsiella pneumoniae M5al.

    PubMed Central

    Goldman, B S; Lin, J T; Stewart, V

    1994-01-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources through the nitrate assimilatory pathway. The structural genes for assimilatory nitrate and nitrite reductases together with genes necessary for nitrate transport form an operon, nasFEDCBA. Expression of the nasF operon is regulated both by general nitrogen control and also by nitrate or nitrite induction. We have identified a gene, nasR, that is necessary for nitrate and nitrite induction. The nasR gene, located immediately upstream of the nasFEDCBA operon, encodes a 44-kDa protein. The NasR protein shares carboxyl-terminal sequence similarity with the AmiR protein of Pseudomonas aeruginosa, the positive regulator of amiE (aliphatic amidase) gene expression. In addition, we present evidence that the nasF operon is not autogenously regulated. Images PMID:8051020

  16. Identification and structure of the nasR gene encoding a nitrate- and nitrite-responsive positive regulator of nasFEDCBA (nitrate assimilation) operon expression in Klebsiella pneumoniae M5al.

    PubMed

    Goldman, B S; Lin, J T; Stewart, V

    1994-08-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources through the nitrate assimilatory pathway. The structural genes for assimilatory nitrate and nitrite reductases together with genes necessary for nitrate transport form an operon, nasFEDCBA. Expression of the nasF operon is regulated both by general nitrogen control and also by nitrate or nitrite induction. We have identified a gene, nasR, that is necessary for nitrate and nitrite induction. The nasR gene, located immediately upstream of the nasFEDCBA operon, encodes a 44-kDa protein. The NasR protein shares carboxyl-terminal sequence similarity with the AmiR protein of Pseudomonas aeruginosa, the positive regulator of amiE (aliphatic amidase) gene expression. In addition, we present evidence that the nasF operon is not autogenously regulated. PMID:8051020

  17. The influence of nitrogen and antimony on the optical quality of InNAs(Sb) alloys

    NASA Astrophysics Data System (ADS)

    Latkowska, M.; Baranowski, M.; Linhart, W. M.; Janiaka, F.; Misiewicz, J.; Segercrantz, N.; Tuomisto, F.; Zhuang, Q.; Krier, A.; Kudrawiec, R.

    2016-03-01

    In this work we present detailed studies of the influence of nitrogen and antimony on the optical quality of InNAs(Sb) alloys. We employed photoluminescence, photoreflectance and positron annihilation spectroscopy to reveal the role of antimony and nitrogen on the improvement/degradation of the optical qualities of InNAs(Sb) alloys. A series of 1 μm-thick InNAs(Sb) layers with different nitrogen and antimony concentrations were grown by molecular beam epitaxy. The results of these investigations show that Sb atoms serve as a surfactant which effectively improves the optical quality of InNAsSb alloys. The influence of nitrogen on the optical quality however is not the same as to what has been reported for other dilute nitrides. We observed an improvement of the optical quality for some nitrogen contents. These issues are comprehensively examined and explained.

  18. Performance assessment of multijunction solar cells incorporating GaInNAsSb

    PubMed Central

    2014-01-01

    We have measured the characteristics of molecular beam epitaxy grown GaInNAsSb solar cells with different bandgaps using AM1.5G real sun illumination. Based on the solar cell diode characteristics and known parameters for state-of-the-art GaInP/GaAs and GaInP/GaAs/Ge cells, we have calculated the realistic potential efficiency increase for GaInP/GaAs/GaInNAsSb and GaInP/GaAs/GaInNAsSb/Ge multijunction solar cells for different current matching conditions. The analyses reveal that realistic GaInNAsSb solar cell parameters, render possible an extraction efficiency of over 36% at 1-sun AM1.5D illumination. PACS 88.40.hj; 88.40.jm; 88.40.jp; 81.15.Hi PMID:24498981

  19. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project Subcommittee Final

    NASA Technical Reports Server (NTRS)

    Johnson, Chuck; Griner, James H.; Hayhurst, Kelly J.; Shively, Robert J.; Consiglio, Maria; Muller, Eric; Murphy, James; Kim, Sam

    2012-01-01

    UAS Integration in the NAS Project overview with details from each of the subprojects. Subprojects include: Communications, Certification, Integrated Test and Evaluation, Human Systems Integration, and Separation Assurance/Sense and Avoid Interoperability.

  20. Structural basis for proteasome formation controlled by an assembly chaperone nas2.

    PubMed

    Satoh, Tadashi; Saeki, Yasushi; Hiromoto, Takeshi; Wang, Ying-Hui; Uekusa, Yoshinori; Yagi, Hirokazu; Yoshihara, Hidehito; Yagi-Utsumi, Maho; Mizushima, Tsunehiro; Tanaka, Keiji; Kato, Koichi

    2014-05-01

    Proteasome formation does not occur due to spontaneous self-organization but results from a highly ordered process assisted by several assembly chaperones. The assembly of the proteasome ATPase subunits is assisted by four client-specific chaperones, of which three have been structurally resolved. Here, we provide the structural basis for the working mechanisms of the last, hereto structurally uncharacterized assembly chaperone, Nas2. We revealed that Nas2 binds to the Rpt5 subunit in a bivalent mode: the N-terminal helical domain of Nas2 masks the Rpt1-interacting surface of Rpt5, whereas its C-terminal PDZ domain caps the C-terminal proteasome-activating motif. Thus, Nas2 operates as a proteasome activation blocker, offering a checkpoint during the formation of the 19S ATPase prior to its docking onto the proteolytic 20S core particle. PMID:24685148

  1. Performance assessment of multijunction solar cells incorporating GaInNAsSb.

    PubMed

    Aho, Arto; Tukiainen, Antti; Polojärvi, Ville; Guina, Mircea

    2014-01-01

    We have measured the characteristics of molecular beam epitaxy grown GaInNAsSb solar cells with different bandgaps using AM1.5G real sun illumination. Based on the solar cell diode characteristics and known parameters for state-of-the-art GaInP/GaAs and GaInP/GaAs/Ge cells, we have calculated the realistic potential efficiency increase for GaInP/GaAs/GaInNAsSb and GaInP/GaAs/GaInNAsSb/Ge multijunction solar cells for different current matching conditions. The analyses reveal that realistic GaInNAsSb solar cell parameters, render possible an extraction efficiency of over 36% at 1-sun AM1.5D illumination. PACS: 88.40.hj; 88.40.jm; 88.40.jp; 81.15.Hi. PMID:24498981

  2. Low temperature grown GaNAsSb: A promising material for photoconductive switch application

    SciTech Connect

    Tan, K. H.; Yoon, S. F.; Wicaksono, S.; Loke, W. K.; Li, D. S.; Saadsaoud, N.; Tripon-Canseliet, C.; Lampin, J. F.; Decoster, D.; Chazelas, J.

    2013-09-09

    We report a photoconductive switch using low temperature grown GaNAsSb as the active material. The GaNAsSb layer was grown at 200 °C by molecular beam epitaxy in conjunction with a radio frequency plasma-assisted nitrogen source and a valved antimony cracker source. The low temperature growth of the GaNAsSb layer increased the dark resistivity of the switch and shortened the carrier lifetime. The switch exhibited a dark resistivity of 10{sup 7} Ω cm, a photo-absorption of up to 2.1 μm, and a carrier lifetime of ∼1.3 ps. These results strongly support the suitability of low temperature grown GaNAsSb in the photoconductive switch application.

  3. Shadow Mode Assessment Using Realistic Technologies for the National Airspace (SMART NAS)

    NASA Technical Reports Server (NTRS)

    Kopardekar, Parimal H.

    2014-01-01

    Develop a simulation and modeling capability that includes: (a) Assessment of multiple parallel universes, (b) Accepts data feeds, (c) Allows for live virtual constructive distribute environment, (d) Enables integrated examinations of concepts, algorithms, technologies and National Airspace System (NAS) architectures.

  4. Física e Arte nas Estações do Ano

    NASA Astrophysics Data System (ADS)

    Pessôa Queiroz, Glória; da Conceição Barbosa Lima, Maria; Navarro Vasconcellos das Mercês, Maria

    2004-12-01

    The paper deals with the subject of the Four Seasons, exploring elements of Science and the Art in order to motivate students or public of museums of science and technology to understand it from their current cultural experiences and of old times. Physics joins to Astronomy to explain the phenomenon, while the use of Music and Painting make possible the immersion in the subject in way to many trips to the imagination capable to awake emotions.A proposal didactic is presented and justified for some consensus of the research in the area of teaching-learning of science, since that related to the persistent alternative conceptions concerning the causes of the changes observed at the different times of the year until the qualitative modelling of phenomena that appeals three-dimensional pedagogical models. Such proposal was developed in the activity named " Hiper interesting Talk: The Four Seasons, Science and Art" in the first Sunday of August/2003 in the Museum of Astronomy, MAST. O artigo trata do tema das Estações do Ano, explorando elementos da Ciência e da Arte como forma de motivar estudantes ou público de museus de ciência e tecnologia a compreendê-lo a partir de vivências culturais atuais e de outras épocas. A Física se junta à Astronomia para explicar o fenômeno, enquanto a Música e a Pintura possibilitam a imersão no tema em meio a muitas viagens à imaginação capazes de despertar emoções.Uma proposta didática é apresentada e justificada por consensos das muitas pesquisas na área de ensino-aprendizagem de ciências, desde os que se referem às persistentes concepções alternativas acerca das causas das mudanças observadas nas diferentes épocas do ano até à modelagem qualitativa de fenômenos que recorre a modelos pedagógicos tridimensionais. Tal proposta foi desenvolvida na atividade "Bate papo Hiperinteressante: As Quatro Estações, Ciência e Arte" realizada no primeiro domingo do mês de agosto de 2003 no Museu de Astronomia.

  5. NasR, a novel RNA-binding protein, mediates nitrate-responsive transcription antitermination of the Klebsiella oxytoca M5al nasF operon leader in vitro.

    PubMed

    Chai, W; Stewart, V

    1998-10-23

    In Klebsiella oxytoca (pneumoniae), enzymes required for nitrate assimilation are encoded by the nasFEDCBA operon. Previous genetic studies led to the conclusion that nitrate and nitrite induction of nasF operon expression is determined by a transcriptional antitermination mechanism. In the presence of nitrate or nitrite, the nasR gene product is hypothesized to inhibit transcription termination at the factor-independent terminator site located in the nasF operon leader region. To test this model in vitro, we first purified NasR as both a maltose binding protein fusion form (MBP-NasR) and a His6-tagged form (His6-NasR). Templates for in vitro transcription contained the nasF operon leader region, with a substitution of the sigma70-dependent tac promoter for the native sigmaN-dependent promoter. We found that in vitro transcription of the leader template terminated at the terminator site, and that MBP-NasR and His6-NasR proteins both caused transcription readthrough of this site in response to nitrate or nitrite. Half-maximal antitermination required nitrate or nitrite at moderate (1 to 10 microM) concentrations, and several other anions tested, including chlorate, were without effect. Previous in vivo analysis of leader deletions identified regions required for both negative regulation (the terminator) and for positive regulation. Results from in vitro transcription of these deletion templates correlated fully with the in vivo analysis. Finally, electrophoresis mobility shift analysis revealed that His6-NasR bound specifically to nasF leader RNA. This binding was independent of nitrate in vitro. These results strongly support the conclusions drawn from previous in vivo analysis, and establish that NasR mediates ligand-responsive transcription antitermination through interaction with nasF leader RNA. PMID:9769209

  6. GaInNAs Junctions for Next-Generation Concentrators: Progress and Prospects

    SciTech Connect

    Friedman, D. J.; Ptak, A. J.; Kurtz, S. R.; Geisz, J. F.; Kiehl, J.

    2005-08-01

    We discuss progress in the development of GaInNAs junctions for application in next-generation multijunction concentrator cells. A significant development is the demonstration of near-100% internal quantum efficiencies in junctions grown by molecular-beam epitaxy. Testing at high currents validates the compatibility of these devices with concentrator operation. The efficiencies of several next-generation multijunction structures incorporating these state-of-the-art GaInNAs junctions are projected.

  7. The NAS Alert System: a look at the first eight years

    USGS Publications Warehouse

    Fuller, Pam L.; Neilson, Matt; Huge, Dane H.

    2013-01-01

    The U.S. Geological Survey's Nonindigenous Aquatic Species (NAS) database program (http://nas.er.usgs.gov) tracks the distribution of introduced aquatic organisms across the United States. Awareness of, and timely response to, novel species introductions by those involved in nonindigenous aquatic species management and research requires a framework for rapid dissemination of occurrence data as it is incorporated into the NAS database. In May 2004, the NAS program developed an alert system to notify registered users of new introductions as part of a national early detection/rapid response system. This article summarizes information on system users and dispatched alerts from the system's inception through the end of 2011. The NAS alert system has registered over 1,700 users, with approximately 800 current subscribers. A total of 1,189 alerts had been transmitted through 2011. More alerts were sent for Florida (134 alerts) than for any other state. Fishes comprise the largest taxonomic group of alerts (440), with mollusks, plants, and crustaceans each containing over 100 alerts. Most alerts were for organisms that were intentionally released (414 alerts), with shipping, escape from captivity, and hitchhiking also representing major vectors. To explore the archive of sent alerts and to register, the search and signup page for the alert system can be found online at http://nas.er.usgs.gov/AlertSystem/default.aspx.

  8. Hydrazine N Source for Growth of GaInNAs for Solar Cells

    SciTech Connect

    Friedman, D. J.; Geisz, G. F.; Kurtz, S. R.; Norman, A. G.; Yeh, Y. C. M.

    1999-05-25

    We evaluate hydrazine (Hy) as a nitrogen precursor source for the growth of GaNAs and GaInNAs for application in 1-eV solar cells lattice-matched to GaAs, and compare it to the more commonly used dimethylhydrazine (DMHy). The incorporation efficiency of N into the GaNAs alloy is found to be one to two orders of magnitude higher with Hy than with DMHy. This high N incorporation makes convenient the growth of GaNAs at higher growth temperatures, Tg=650 C, and arsine flows, AsH3/III=44, than are generally possible with the use of DMHy. GaInNAs and GaNAs solar cells are grown under these growth conditions and compared to a GaAs cell grown under the same conditions to determine the extent to which the poor minority-carrier properties routinely observed for the N-containing material can be attributed to the growth conditions. Finally, the background carrier concentrations for Hy- and DMHy-grown material are compared, and little difference is found between the two sources..

  9. Dilute-As AlNAs Alloy for Deep-Ultraviolet Emitter

    PubMed Central

    Tan, Chee-Keong; Borovac, Damir; Sun, Wei; Tansu, Nelson

    2016-01-01

    The band structures of dilute-As AlNAs alloys with As composition ranging from 0% up to 12.5% are studied by using First-Principle Density Functional Theory (DFT) calculation. The energy band gap shows remarkable reduction from 6.19 eV to 3.87 eV with small amount of As content in the AlNAs alloy, which covers the deep ultraviolet (UV) spectral regime. A giant bowing parameter of 30.5 eV ± 0.5 eV for AlNAs alloy is obtained. In addition, our analysis shows that the crossover between crystal field split-off (CH) band and heavy hole (HH) bands occurs in the dilute-As AlNAs alloy with As-content of ~1.5%. This result implies the possibility of dominant transverse electric (TE)-polarized emission by using AlNAs alloy with dilute amount of As-content. Our findings indicate the potential of dilute-As AlNAs alloy as the new active region material for TE-polarized III-Nitride-based deep UV light emitters. PMID:26905060

  10. EM International. Volume 1

    SciTech Connect

    Not Available

    1993-07-01

    It is the intent of EM International to describe the Office of Environmental Restoration and Waste Management`s (EM`s) various roles and responsibilities within the international community. Cooperative agreements and programs, descriptions of projects and technologies, and synopses of visits to international sites are all highlighted in this semiannual journal. Focus on EM programs in this issue is on international collaboration in vitrification projects. Technology highlights covers: in situ sealing for contaminated sites; and remote sensors for toxic pollutants. Section on profiles of countries includes: Arctic contamination by the former Soviet Union, and EM activities with Germany--cooperative arrangements.

  11. NAS Parallel Benchmark. Results 11-96: Performance Comparison of HPF and MPI Based NAS Parallel Benchmarks. 1.0

    NASA Technical Reports Server (NTRS)

    Saini, Subash; Bailey, David; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    High Performance Fortran (HPF), the high-level language for parallel Fortran programming, is based on Fortran 90. HALF was defined by an informal standards committee known as the High Performance Fortran Forum (HPFF) in 1993, and modeled on TMC's CM Fortran language. Several HPF features have since been incorporated into the draft ANSI/ISO Fortran 95, the next formal revision of the Fortran standard. HPF allows users to write a single parallel program that can execute on a serial machine, a shared-memory parallel machine, or a distributed-memory parallel machine. HPF eliminates the complex, error-prone task of explicitly specifying how, where, and when to pass messages between processors on distributed-memory machines, or when to synchronize processors on shared-memory machines. HPF is designed in a way that allows the programmer to code an application at a high level, and then selectively optimize portions of the code by dropping into message-passing or calling tuned library routines as 'extrinsics'. Compilers supporting High Performance Fortran features first appeared in late 1994 and early 1995 from Applied Parallel Research (APR) Digital Equipment Corporation, and The Portland Group (PGI). IBM introduced an HPF compiler for the IBM RS/6000 SP/2 in April of 1996. Over the past two years, these implementations have shown steady improvement in terms of both features and performance. The performance of various hardware/ programming model (HPF and MPI (message passing interface)) combinations will be compared, based on latest NAS (NASA Advanced Supercomputing) Parallel Benchmark (NPB) results, thus providing a cross-machine and cross-model comparison. Specifically, HPF based NPB results will be compared with MPI based NPB results to provide perspective on performance currently obtainable using HPF versus MPI or versus hand-tuned implementations such as those supplied by the hardware vendors. In addition we would also present NPB (Version 1.0) performance results for

  12. Testing New Programming Paradigms with NAS Parallel Benchmarks

    NASA Technical Reports Server (NTRS)

    Jin, H.; Frumkin, M.; Schultz, M.; Yan, J.

    2000-01-01

    Over the past decade, high performance computing has evolved rapidly, not only in hardware architectures but also with increasing complexity of real applications. Technologies have been developing to aim at scaling up to thousands of processors on both distributed and shared memory systems. Development of parallel programs on these computers is always a challenging task. Today, writing parallel programs with message passing (e.g. MPI) is the most popular way of achieving scalability and high performance. However, writing message passing programs is difficult and error prone. Recent years new effort has been made in defining new parallel programming paradigms. The best examples are: HPF (based on data parallelism) and OpenMP (based on shared memory parallelism). Both provide simple and clear extensions to sequential programs, thus greatly simplify the tedious tasks encountered in writing message passing programs. HPF is independent of memory hierarchy, however, due to the immaturity of compiler technology its performance is still questionable. Although use of parallel compiler directives is not new, OpenMP offers a portable solution in the shared-memory domain. Another important development involves the tremendous progress in the internet and its associated technology. Although still in its infancy, Java promisses portability in a heterogeneous environment and offers possibility to "compile once and run anywhere." In light of testing these new technologies, we implemented new parallel versions of the NAS Parallel Benchmarks (NPBs) with HPF and OpenMP directives, and extended the work with Java and Java-threads. The purpose of this study is to examine the effectiveness of alternative programming paradigms. NPBs consist of five kernels and three simulated applications that mimic the computation and data movement of large scale computational fluid dynamics (CFD) applications. We started with the serial version included in NPB2.3. Optimization of memory and cache usage

  13. On Ensino de Astronomia nas Cidades de Ribeirão Pires e Rio Grande da Serra

    NASA Astrophysics Data System (ADS)

    Faria, R. Z.; Voelzke, M. R.

    2007-08-01

    Apesar da astronomia ser um dos temas indicados pelos Parâmetros Curriculares Nacionais, observa-se que poucas mudanças ocorreram desde a implementação do mesmo em sala de aula. A presente pesquisa diz respeito sobre como os tópicos de astronomia estão sendo abordados pelos professores no ensino médio. Optou-se por aplicar um questionário com os professores que ministram a disciplina de física. Os mesmos trabalham em escolas estaduais situadas nas cidades de Ribeirão Pires e Rio Grande da Serra, ambas subordinadas a Diretoria de Ensino de Mauá, no Estado de São Paulo. O questionário foi aplicado durante o 2° semestre de 2006. Até o momento os resultados são preliminares. Dos 82,0% dos professores que responderam ao questionário no município de Rio Grande da Serra, 66,7% não aplicaram nenhum tópico de astronomia, 77,8% não utilizaram qualquer tipo de programa computacional, 66,7% não utilizaram laboratório, que 77,8% nunca levaram os alunos a museus e ou planetários e que 66,7% não indicaram qualquer tipo de revista ou livro sobre astronomia aos seus alunos. No município de Ribeirão Pires, 53,3% dos professores responderam ao questionário, destes 75,0% não aplicaram nenhum tópico de astronomia, 93,8% não utilizaram qualquer tipo de programa computacional, 75,0% não utilizaram laboratório, 81,3% nunca levaram os alunos a museus e ou planetário e 56,3% não indicaram qualquer tipo de revista ou livro sobre astronomia ao seus alunos. Apesar da maioria dos professores reconhecerem que o conteúdo de astronomia influi na formação do jovem, os mesmos não incluem o tema em seus planejamentos escolares.

  14. UAS in the NAS: Survey Responses by ATC, Manned Aircraft Pilots, and UAS Pilots

    NASA Technical Reports Server (NTRS)

    Comstock, James R., Jr.; McAdaragh, Raymon; Ghatas, Rania W.; Burdette, Daniel W.; Trujillo, Anna C.

    2014-01-01

    NASA currently is working with industry and the Federal Aviation Administration (FAA) to establish future requirements for Unmanned Aircraft Systems (UAS) flying in the National Airspace System (NAS). To work these issues NASA has established a multi-center "UAS Integration in the NAS" project. In order to establish Ground Control Station requirements for UAS, the perspective of each of the major players in NAS operations was desired. Three on-line surveys were administered that focused on Air Traffic Controllers (ATC), pilots of manned aircraft, and pilots of UAS. Follow-up telephone interviews were conducted with some survey respondents. The survey questions addressed UAS control, navigation, and communications from the perspective of small and large unmanned aircraft. Questions also addressed issues of UAS equipage, especially with regard to sense and avoid capabilities. From the civilian ATC and military ATC perspectives, of particular interest are how mixed operations (manned / UAS) have worked in the past and the role of aircraft equipage. Knowledge gained from this information is expected to assist the NASA UAS Integration in the NAS project in directing research foci thus assisting the FAA in the development of rules, regulations, and policies related to UAS in the NAS.

  15. UAS in the NAS: Survey Responses by ATC, Manned Aircraft Pilots, and UAS Pilots

    NASA Technical Reports Server (NTRS)

    Comstock, James R., Jr.; McAdaragh, Raymon; Ghatas, Rania W.; Burdette, Daniel W.; Trujillo, Anna C.

    2013-01-01

    NASA currently is working with industry and the Federal Aviation Administration (FAA) to establish future requirements for Unmanned Aircraft Systems (UAS) flying in the National Airspace System (NAS). To work these issues NASA has established a multi-center UAS Integration in the NAS project. In order to establish Ground Control Station requirements for UAS, the perspective of each of the major players in NAS operations was desired. Three on-line surveys were administered that focused on Air Traffic Controllers (ATC), pilots of manned aircraft, and pilots of UAS. Follow-up telephone interviews were conducted with some survey respondents. The survey questions addressed UAS control, navigation, and communications from the perspective of small and large unmanned aircraft. Questions also addressed issues of UAS equipage, especially with regard to sense and avoid capabilities. From the ATC and military ATC perspective, of particular interest is how mixed-operations (manned/UAS) have worked in the past and the role of aircraft equipage. Knowledge gained from this information is expected to assist the NASA UAS in the NAS project in directing research foci thus assisting the FAA in the development of rules, regulations, and policies related to UAS in the NAS.

  16. General Nitrogen Regulation of Nitrate Assimilation Regulatory Gene nasR Expression in Klebsiella oxytoca M5al

    PubMed Central

    Wu, Stephen Qitu; Chai, Weihang; Lin, Janine T.; Stewart, Valley

    1999-01-01

    Klebsiella oxytoca can assimilate nitrate and nitrite by using enzymes encoded by the nasFEDCBA operon. Expression of the nasF operon is controlled by general nitrogen regulation (Ntr) via the NtrC transcription activator and by pathway-specific nitrate and nitrite induction via the NasR transcription antiterminator. This paper reports our analysis of nasR gene expression. We constructed strains bearing single-copy Φ(nasR-lacZ) operon fusions within the chromosomal rhaBAD-rhaSR locus. The expression of ΔrhaBS::[Φ(nasR-lacZ)] operon fusions was induced about 10-fold during nitrogen-limited growth. Induction was reduced in both ntrC and rpoN null mutants, indicating that Ntr control of nasR gene expression requires the NtrC and ςN (ς54) proteins. Sequence inspection of the nasR control region reveals an apparent ςN-dependent promoter but no apparent NtrC protein binding sites. Analysis of site-specific mutations coupled with primer extension analysis authenticated the ςN-dependent nasR promoter. Fusion constructs with only about 70 nucleotides (nt) upstream of the transcription initiation site exhibited patterns of β-galactosidase expression indistinguishable from Φ(nasR-lacZ) constructs with about 470 nt upstream. Expression was independent of the Nac protein, implying that NtrC is a direct activator of nasR transcription. Together, these results indicate that nasR gene expression does not require specific upstream NtrC-binding sequences, as previously noted for argT gene expression in Salmonella typhimurium (G. Schmitz, K. Nikaido, and G. F.-L. Ames, Mol. Gen. Genet. 215:107–117, 1988). PMID:10572131

  17. Identification and functional analysis of a nitrate assimilation operon nasACKBDEF from Amycolatopsis mediterranei U32.

    PubMed

    Shao, Zhihui; Gao, Jin; Ding, Xiaoming; Wang, Jin; Chiao, Juishen; Zhao, Guoping

    2011-07-01

    Nitrate assimilation has been well studied for Gram-negative bacteria but not so much in the Gram-positive actinomycetes up to date. In a rifamycin SV-producing actinomycete, Amycolatopsis mediterranei strain U32, nitrate not only can be used as a sole nitrogen source but also remarkably stimulates the antibiotic production along with regulating the related metabolic enzymes. A gene cluster of nasACKBDEF was cloned from a U32 genomic library by in situ hybridization screening with a heterogeneous nasB probe and confirmed later by whole genome sequence, corresponding to the protein coding genes of AMED_1121 to AMED_1127. These genes were co-transcribed as an operon, concomitantly repressed by ammonium while activated with supplement of either nitrate or nitrite. Genetic and biochemical analyses identified the essential nitrate/nitrite assimilation functions of the encoded proteins, orderly, the assimilatory nitrate reductase catalytic subunit (NasA), nitrate reductase electron transfer subunit (NasC), nitrate/nitrite transporter (NasK), assimilatory nitrite reductase large subunit (NasB) and small subunit (NasD), bifunctional uroporphyrinogen-III synthase (NasE), and an unknown function protein (NasF). Comparing rifamycin SV production and the level of transcription of nasB and rifE from U32 and its individual nas mutants in Bennet medium with or without nitrate indicated that nitrate assimilation function encoded by the nas operon played an essential role in the "nitrate stimulated" rifamycin production but had no effect upon the transcription regulation of the primary and secondary metabolic genes related to rifamycin biosynthesis. PMID:21424691

  18. General nitrogen regulation of nitrate assimilation regulatory gene nasR expression in Klebsiella oxytoca M5al.

    PubMed

    Wu, S Q; Chai, W; Lin, J T; Stewart, V

    1999-12-01

    Klebsiella oxytoca can assimilate nitrate and nitrite by using enzymes encoded by the nasFEDCBA operon. Expression of the nasF operon is controlled by general nitrogen regulation (Ntr) via the NtrC transcription activator and by pathway-specific nitrate and nitrite induction via the NasR transcription antiterminator. This paper reports our analysis of nasR gene expression. We constructed strains bearing single-copy Phi(nasR-lacZ) operon fusions within the chromosomal rhaBAD-rhaSR locus. The expression of DeltarhaBS::[Phi(nasR-lacZ)] operon fusions was induced about 10-fold during nitrogen-limited growth. Induction was reduced in both ntrC and rpoN null mutants, indicating that Ntr control of nasR gene expression requires the NtrC and sigma(N) (sigma(54)) proteins. Sequence inspection of the nasR control region reveals an apparent sigma(N)-dependent promoter but no apparent NtrC protein binding sites. Analysis of site-specific mutations coupled with primer extension analysis authenticated the sigma(N)-dependent nasR promoter. Fusion constructs with only about 70 nucleotides (nt) upstream of the transcription initiation site exhibited patterns of beta-galactosidase expression indistinguishable from Phi(nasR-lacZ) constructs with about 470 nt upstream. Expression was independent of the Nac protein, implying that NtrC is a direct activator of nasR transcription. Together, these results indicate that nasR gene expression does not require specific upstream NtrC-binding sequences, as previously noted for argT gene expression in Salmonella typhimurium (G. Schmitz, K. Nikaido, and G. F.-L. Ames, Mol. Gen. Genet. 215:107-117, 1988). PMID:10572131

  19. Improved performance in GaInNAs solar cells by hydrogen passivation

    SciTech Connect

    Fukuda, M.; Whiteside, V. R.; Keay, J. C.; Meleco, A.; Sellers, I. R.; Hossain, K.; Golding, T. D.; Leroux, M.; Al Khalfioui, M.

    2015-04-06

    The effect of UV-activated hydrogenation on the performance of GaInNAs solar cells is presented. A proof-of-principle investigation was performed on non-optimum GaInNAs cells, which allowed a clearer investigation of the role of passivation on the intrinsic nitrogen-related defects in these materials. Upon optimized hydrogenation of GaInNAs, a significant reduction in the presence of defect and impurity based luminescence is observed as compared to that of unpassivated reference material. This improvement in the optical properties is directly transferred to an improved performance in solar cell operation, with a more than two-fold improvement in the external quantum efficiency and short circuit current density upon hydrogenation. Temperature dependent photovoltaic measurements indicate a strong contribution of carrier localization and detrapping processes, with non-radiative processes dominating in the reference materials, and evidence for additional strong radiative losses in the hydrogenated solar cells.

  20. GaNAsP: An intermediate band semiconductor grown by gas-source molecular beam epitaxy

    SciTech Connect

    Kuang, Y. J.; Yu, K. M.; Walukiewicz, W.; Kudrawiec, R.; Luce, A. V.; Ting, M.; Tu, C. W.

    2013-03-18

    Dilute nitride GaNAsP thin films were grown via a GaAsP metamorphic buffer on GaP(100) substrate with gas-source molecular beam epitaxy. The compositions of this III-V-V-V compound were determined by channeling Rutherford backscattering spectroscopy and nuclear reaction analysis. Photoreflectance shows two distinctive transitions from the valence band to the split conduction bands due to N incorporation. Photoluminescence and optical absorption show the fundamental bandgap of Ga(N)AsP is largely tailored by the small amount of N. The observed multiband characteristics and the bandgap tunability of GaNAsP are two merits that fit into the intermediate-band solar cell roadmap, and GaNAsP of high crystal quality provides a strong candidate for intermediate band solar cell materials.

  1. Examination of Frameworks for Safe Integration of Intelligent Small UAS into the NAS

    NASA Technical Reports Server (NTRS)

    Logan, Michael J.

    2012-01-01

    This paper discusses a proposed framework for the safe integration of small unmanned aerial systems (sUAS) into the National Airspace System (NAS). The paper briefly examines the potential uses of sUAS to build an understanding of the location and frequency of potential future flight operations based on the future applications of the sUAS systems. The paper then examines the types of systems that would be required to meet the application-level demand to determine "classes" of platforms and operations. A framework for categorization of the "intelligence" level of the UAS is postulated for purposes of NAS integration. Finally, constraints on the intelligent systems are postulated to ensure their ease of integration into the NAS.

  2. Epitaxial growth and picosecond carrier dynamics of GaInAs/GaInNAs superlattices

    SciTech Connect

    Martin, M.; Mangeney, J.; Travers, L.; Harmand, J. C.; Mauguin, O.; Patriarche, G.

    2009-10-05

    We study GaInAs/GaInNAs superlattice structures grown on InP substrate as potential candidates for photoconductive terahertz devices or saturable absorbers working at 1.55 {mu}m wavelength. The N-rich GaInNAs layers are flat, with no three-dimensional islanding, and act as trapping layers where carriers can recombine rapidly. The carrier lifetime in GaInAs/GaInNAs superlattice was measured for various growth parameters using time-resolved differential transmission experiments at 1.55 {mu}m wavelength. The carrier lifetime is found to depend strongly on N content and can be reduced down to 3.8 ps for samples with 14% of N. The mechanisms involved in the capture process of photocarriers are discussed.

  3. GaNAsP: An intermediate band semiconductor grown by gas-source molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Kuang, Y. J.; Yu, K. M.; Kudrawiec, R.; Luce, A. V.; Ting, M.; Walukiewicz, W.; Tu, C. W.

    2013-03-01

    Dilute nitride GaNAsP thin films were grown via a GaAsP metamorphic buffer on GaP(100) substrate with gas-source molecular beam epitaxy. The compositions of this III-V-V-V compound were determined by channeling Rutherford backscattering spectroscopy and nuclear reaction analysis. Photoreflectance shows two distinctive transitions from the valence band to the split conduction bands due to N incorporation. Photoluminescence and optical absorption show the fundamental bandgap of Ga(N)AsP is largely tailored by the small amount of N. The observed multiband characteristics and the bandgap tunability of GaNAsP are two merits that fit into the intermediate-band solar cell roadmap, and GaNAsP of high crystal quality provides a strong candidate for intermediate band solar cell materials.

  4. TRICARE; elimination of the non-availability statement (NAS) requirement for non-emergency inpatient mental health care. Final rule.

    PubMed

    2013-02-26

    This final rule eliminates the requirement that states a NAS is needed for non-emergency inpatient mental health care in order for a TRICARE Standard beneficiary's claim to be paid. Currently, NAS are required for non-emergency inpatient mental health care for TRICARE Standard beneficiaries who live within a military treatment facility catchment area. At this time, the number of NASs issued is negligible as most mental health admissions are emergency admissions. Requiring a NAS for a relatively few non-emergency inpatient mental health admissions is disproportionate to the cost of maintaining the systems necessary to process and coordinate the NAS. PMID:23476989

  5. Compositional dependence of the band gap in Ga(NAsP) quantum well heterostructures

    SciTech Connect

    Jandieri, K. Ludewig, P.; Wegele, T.; Beyer, A.; Kunert, B.; Springer, P.; Baranovskii, S. D.; Koch, S. W.; Volz, K.; Stolz, W.

    2015-08-14

    We present experimental and theoretical studies of the composition dependence of the direct band gap energy in Ga(NAsP)/GaP quantum well heterostructures grown on either (001) GaP- or Si-substrates. The theoretical description takes into account the band anti-crossing model for the conduction band as well as the modification of the valence subband structure due to the strain resulting from the pseudomorphic epitaxial growth on the respective substrate. The composition dependence of the direct band gap of Ga(NAsP) is obtained for a wide range of nitrogen and phosphorus contents relevant for laser applications on Si-substrate.

  6. Comparison of Na/S and LiAl/FeS batteries

    NASA Astrophysics Data System (ADS)

    Knoedler, R.

    NaS and LiAl/FeS batteries, both promising candidates for electric-vehicle propulsion and load leveling applications, are compared by assessing 25 different properties of each system. The most important of these properties, including the specific energy of cells and batteries, maximum specific power, lifetime, safety, key technical problems, and economic considerations, are discussed in detail. It is shown that both types of batteries qualify as high-performance batteries. The NaS system has a slight advantage for applications in West Germany (mainly electric vehicle propulsion; no Li resources); for applications in the United States (electric vehicle propulsion and load leveling), both systems are equally suitable.

  7. Compositional dependence of the band gap in Ga(NAsP) quantum well heterostructures

    NASA Astrophysics Data System (ADS)

    Jandieri, K.; Ludewig, P.; Wegele, T.; Beyer, A.; Kunert, B.; Springer, P.; Baranovskii, S. D.; Koch, S. W.; Volz, K.; Stolz, W.

    2015-08-01

    We present experimental and theoretical studies of the composition dependence of the direct band gap energy in Ga(NAsP)/GaP quantum well heterostructures grown on either (001) GaP- or Si-substrates. The theoretical description takes into account the band anti-crossing model for the conduction band as well as the modification of the valence subband structure due to the strain resulting from the pseudomorphic epitaxial growth on the respective substrate. The composition dependence of the direct band gap of Ga(NAsP) is obtained for a wide range of nitrogen and phosphorus contents relevant for laser applications on Si-substrate.

  8. The role of specialized processors in the NAS program - Retrospective/prospective

    NASA Technical Reports Server (NTRS)

    Levin, Eugene; Preston, Frank

    1988-01-01

    The Numerical Aerodynamic Simulation (NAS) Program was initiated by NASA to establish a national resource for scientific research and engineering applications of computational fluid dynamics. This paper examines the changing views of the roles of general purpose and special purpose processors in this program in response to changes in technology as well as changes in perceived needs. The time period covered extends from more than 10 years ago, through the present, and concludes with some speculative concepts for the future roles of specialized processors in the advanced NAS system.

  9. Solar cells with (BGaIn)As and (InGa)(NAs) as absorption layers

    NASA Astrophysics Data System (ADS)

    Leibiger, G.; Krahmer, C.; Bauer, J.; Herrnberger, H.; Gottschalch, V.

    2004-12-01

    (BGaIn)As and (InGa)(NAs) have been tested for the application in solar cells. Single layers have been grown lattice matched on GaAs using MOVPE at low growth temperatures. Optical properties, i.e. band-gap energies and optical constants have been determined with photoluminescence and spectroscopic ellipsometry. n- and p-Type doping have been achieved with disilane and diethylzinc as doping precursors, respectively. Corresponding free carrier properties are discussed based on Hall measurements. Different solar cell structures with n- and p-doped (BGaIn)As and (InGa)(NAs) as base layer have been grown and successfully tested.

  10. Transcriptional profile reveals altered hepatic lipid and cholesterol metabolism in hyposulfatemic NaS1 null mice.

    PubMed

    Dawson, Paul Anthony; Gardiner, Brooke; Grimmond, Sean; Markovich, Daniel

    2006-07-12

    Sulfate plays an essential role in human growth and development, and its circulating levels are maintained by the renal Na+-SO42- cotransporter, NaS1. We previously generated a NaS1 knockout (Nas1-/-) mouse, an animal model for hyposulfatemia, that exhibits reduced growth and liver abnormalities including hepatomegaly. In this study, we investigated the hepatic gene expression profile of Nas1-/- mice using oligonucleotide microarrays. The mRNA expression levels of 92 genes with known functional roles in metabolism, cell signaling, cell defense, immune response, cell structure, transcription, or protein synthesis were increased (n = 51) or decreased (n = 41) in Nas1-/- mice when compared with Nas1+/+ mice. The most upregulated transcript levels in Nas1-/- mice were found for the sulfotransferase genes, Sult3a1 (approximately 500% increase) and Sult2a2 (100% increase), whereas the metallothionein-1 gene, Mt1, was among the most downregulated genes (70% decrease). Several genes involved in lipid and cholesterol metabolism, including Scd1, Acly, Gpam, Elov16, Acsl5, Mvd, Insig1, and Apoa4, were found to be upregulated (> or = 30% increase) in Nas1-/- mice. In addition, Nas1-/- mice exhibited increased levels of hepatic lipid (approximately 16% increase), serum cholesterol (approximately 20% increase), and low-density lipoprotein (approximately 100% increase) and reduced hepatic glycogen (approximately 50% decrease) levels. In conclusion, these data suggest an altered lipid and cholesterol metabolism in the hyposulfatemic Nas1-/- mouse and provide new insights into the metabolic state of the liver in Nas1-/- mice. PMID:16621889

  11. 48 CFR 852.236-83 - Payments under fixed-price construction contracts (including NAS).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Failure either to meet schedules in Section Network Analysis System (NAS), or to process the Interim Arrow Diagram/Complete Project Arrow Diagram; (iii) Failure to present submittals in a timely manner; or (iv... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Payments under...

  12. Beyond the NAS Parallel Benchmarks: Measuring Dynamic Program Performance and Grid Computing Applications

    NASA Technical Reports Server (NTRS)

    VanderWijngaart, Rob F.; Biswas, Rupak; Frumkin, Michael; Feng, Huiyu; Biegel, Bryan (Technical Monitor)

    2001-01-01

    The contents include: 1) A brief history of NPB; 2) What is (not) being measured by NPB; 3) Irregular dynamic applications (UA Benchmark); and 4) Wide area distributed computing (NAS Grid Benchmarks-NGB). This paper is presented in viewgraph form.

  13. A thermo-mechanical stress prediction model for contemporary planar sodium sulfur (NaS) cells

    NASA Astrophysics Data System (ADS)

    Jung, Keeyoung; Colker, Jeffrey P.; Cao, Yuzhe; Kim, Goun; Park, Yoon-Cheol; Kim, Chang-Soo

    2016-08-01

    We introduce a comprehensive finite-element analysis (FEA) computational model to accurately predict the thermo-mechanical stresses at heterogeneous joints and components of large-size sodium sulfur (NaS) cells during thermal cycling. Quantification of the thermo-mechanical stress is important because the accumulation of stress during cell assembly and/or operation is one of the critical issues in developing practical planar NaS cells. The computational model is developed based on relevant experimental assembly and operation conditions to predict the detailed stress field of a state-of-the-art planar NaS cell. Prior to the freeze-and-thaw thermal cycle simulation, residual stresses generated from the actual high temperature cell assembly procedures are calculated and implemented into the subsequent model. The calculation results show that large stresses are developed on the outer surface of the insulating header and the solid electrolyte, where component fracture is frequently observed in the experimental cell fabrication process. The impacts of the coefficients of thermal expansion (CTE) of glass materials and the thicknesses of cell container on the stress accumulation are also evaluated to improve the cell manufacturing procedure and to guide the material choices for enhanced thermo-mechanical stability of large-size NaS cells.

  14. 48 CFR 852.236-82 - Payments under fixed-price construction contracts (without NAS).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Payments under fixed-price construction contracts (without NAS). 852.236-82 Section 852.236-82 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses...

  15. Composition modulation in GaInNAs quantum wells: Comparison of experiment and theory

    NASA Astrophysics Data System (ADS)

    Herrera, M.; González, D.; Hopkinson, M.; Gutiérrez, M.; Navaretti, P.; Liu, H. Y.; García, R.

    2005-04-01

    Composition modulation observed in GaInNAs quantum wells imposes an important handicap to their potential application within optical components, particularly as the indium and nitrogen contents are increased to reach longer wavelengths. In this paper, we compare our experimental results of phase separation in GaInNAs quantum wells grown at different temperatures with recent theoretical models of spinodal decomposition from the literature. This comparison has shown that the regular solution approximation, which explains the higher composition modulation compared to GaInAs samples, provides a more appropriate explanation of GaInNAs decomposition than the usual delta lattice-parameter approximation. Transmission electron microscopy shows no composition modulation contrasts with the chemical sensitive 002 dark field reflection and a strong increase in the intensity of the strain contrasts observed with 220 bright field reflection as the growth temperature increases from 360to460°C. These observations can be explained by an uncoupling between N and In composition profiles forming separate In-rich and N-rich regions according to the regular solution approximation model. We therefore believe that the compositional fluctuations in GaInNAs are not only due to GaInAs decomposition, but that an uncoupled modulation of the III and V elements is also present.

  16. 48 CFR 852.236-82 - Payments under fixed-price construction contracts (without NAS).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Payments under fixed-price construction contracts (without NAS). 852.236-82 Section 852.236-82 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses...

  17. Comparison of Origin 2000 and Origin 3000 Using NAS Parallel Benchmarks

    NASA Technical Reports Server (NTRS)

    Turney, Raymond D.

    2001-01-01

    This report describes results of benchmark tests on the Origin 3000 system currently being installed at the NASA Ames National Advanced Supercomputing facility. This machine will ultimately contain 1024 R14K processors. The first part of the system, installed in November, 2000 and named mendel, is an Origin 3000 with 128 R12K processors. For comparison purposes, the tests were also run on lomax, an Origin 2000 with R12K processors. The BT, LU, and SP application benchmarks in the NAS Parallel Benchmark Suite and the kernel benchmark FT were chosen to determine system performance and measure the impact of changes on the machine as it evolves. Having been written to measure performance on Computational Fluid Dynamics applications, these benchmarks are assumed appropriate to represent the NAS workload. Since the NAS runs both message passing (MPI) and shared-memory, compiler directive type codes, both MPI and OpenMP versions of the benchmarks were used. The MPI versions used were the latest official release of the NAS Parallel Benchmarks, version 2.3. The OpenMP versiqns used were PBN3b2, a beta version that is in the process of being released. NPB 2.3 and PBN 3b2 are technically different benchmarks, and NPB results are not directly comparable to PBN results.

  18. UAS Integration in the NAS Project: Integrated Test and LVC Infrastructure

    NASA Technical Reports Server (NTRS)

    Murphy, Jim; Hoang, Ty

    2015-01-01

    Overview presentation of the Integrated Test and Evaluation sub-project of the Unmanned Aircraft System (UAS) in the National Airspace System (NAS). The emphasis of the presentation is the Live, Virtual, and Constructive (LVC) system (a broadly used name for classifying modeling and simulation) infrastructure and use of external assets and connection.

  19. UAS-NAS Integrated Human in the Loop: Test Environment Report

    NASA Technical Reports Server (NTRS)

    Murphy, Jim; Otto, Neil; Jovic, Srba

    2015-01-01

    The desire and ability to fly Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) is of increasing urgency. The application of unmanned aircraft to perform national security, defense, scientific, and emergency management are driving the critical need for less restrictive access by UAS to the NAS. UAS represent a new capability that will provide a variety of services in the government (public) and commercial (civil) aviation sectors. The growth of this potential industry has not yet been realized due to the lack of a common understanding of what is required to safely operate UAS in the NAS. NASA's UAS Integration in the NAS Project is conducting research in the areas of Separation Assurance/Sense and Avoid Interoperability (SSI), Human Systems Integration (HSI), and Communication to support reducing the barriers of UAS access to the NAS. This research was broken into two research themes namely, UAS Integration and Test Infrastructure. UAS Integration focuses on airspace integration procedures and performance standards to enable UAS integration in the air transportation system, covering Sense and Avoid (SAA) performance standards, command and control performance standards, and human systems integration. The focus of the Test Infrastructure theme was to enable development and validation of airspace integration procedures and performance standards, including the execution of integrated test and evaluation. In support of the integrated test and evaluation efforts, the Project developed an adaptable, scalable, and schedulable relevant test environment incorporating live, virtual, and constructive elements capable of validating concepts and technologies for unmanned aircraft systems to safely operate in the NAS. To accomplish this task, the Project planned to conduct three integrated events: a Human-in-the-Loop simulation and two Flight Test series that integrated key concepts, technologies and/or procedures in a relevant air traffic environment. Each of

  20. Estudo exaustivo e sistemático de erros nas provas da olimpíada brasileira de astronomia - resultados preliminares

    NASA Astrophysics Data System (ADS)

    Oliveira, F. S.; Canalle, J. B. G.; Villas da Rocha, J. F.

    2003-08-01

    A Olimpíada Brasileira de Astronomia (OBA) contou, em sua quinta edição, com a participação de mais de 60 mil alunos dos ensinos fundamental e médio de praticamente todo o território nacional. Uma das formas de controle que a sua coordenação nacional possui sobre a correção, levada a cabo pelos professores que as aplicaram, é a do envio, por parte destes professores, das 10 melhores provas de cada um dos três níveis nos quais a Olimpíada é realizada. Assim, e dado ao caráter discursivo das provas da Olimpíada, a sua coordenação nacional dispõe de um vasto acervo sobre as concepções, certas ou erradas, dos alunos que dela participaram. Este conjunto de dados jamais fora explorado até o presente trabalho que pretende ser, neste sentido, inaugural. Nas provas dos níveis I e II da V OBA, que abrangem todo o conjunto do ensino fundamental, uma das questões versava sobre a noção que os alunos tinham sobre como os habitantes da Terra situam-se sobre sua superfície. Fizemos um estudo sistemático das respostas a esta questão. Primeiramente, todas as modalidades de erros foram levantadas; em seguida, realizamos uma distribuição por idade tanto do índice de acerto como da ocorrência e da distribuição de cada erro. Como resultado, obtivemos que, em ambos os níveis: 1) as concepções errôneas não se apresentam distribuídas aleatoriamente; 2) há uma concentração no tipo de erro apresentado; 3) há uma tendência de progressivo acerto com relação à idade quando os dados são considerados em termos nacionais; 4) esta tendência nacional é fraca ou mesmo não é verificada em alguns dos estados com maior patamar de acerto.

  1. Meeting of Experts on NASA's Unmanned Aircraft System (UAS) Integration in the National Airspace Systems (NAS) Project

    NASA Technical Reports Server (NTRS)

    Wolfe, Jean; Bauer, Jeff; Bixby, C.J.; Lauderdale, Todd; Shively, Jay; Griner, James; Hayhurst, Kelly

    2010-01-01

    Topics discussed include: Aeronautics Research Mission Directorate Integrated Systems Research Program (ISRP) and UAS Integration in the NAS Project; UAS Integration into the NAS Project; Separation Assurance and Collision Avoidance; Pilot Aircraft Interface Objectives/Rationale; Communication; Certification; and Integrated Tests and Evaluations.

  2. 76 FR 57690 - TRICARE; Elimination of the Non-Availability Statement (NAS) Requirement for Non-Emergency...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-16

    ... (NAS) Requirement for Non-Emergency Inpatient Mental Health Care AGENCY: Office of the Secretary... states a NAS is needed for non-emergency inpatient mental health care in order for a TRICARE Standard... the MTF catchment area for non-emergency inpatient mental health care. Currently, the number of...

  3. Defect study of molecular beam epitaxy grown undoped GaInNAsSb thin film using junction-capacitance spectroscopy

    SciTech Connect

    Monirul Islam, Muhammad; Miyashita, Naoya; Ahsan, Nazmul; Okada, Yoshitaka

    2013-02-18

    Defects in undoped GaInNAsSb thin film (i-GaInNAsSb) were investigated by junction-capacitance technique using admittance and transient photocapacitance (TPC) spectroscopy. An electron trap D2 was identified at 0.34 eV below the conduction band (E{sub C}) of i-GaInNAsSb using admittance spectroscopy. Optical transition of valance band (E{sub V}) electrons to a localized state OH1 (E{sub V} + 0.75 eV) was manifested in negative TPC signal. Combined activation energy of OH1 and D2 defect corresponds to the band-gap of i-GaInNAsSb, suggesting that OH1/D2 acts as an efficient recombination center. TPC signal at {approx}1.59 eV above E{sub V} was attributed to the nitrogen-induced localized state in GaInNAsSb.

  4. Nitrogen and oxygen regulation of Bacillus subtilis nasDEF encoding NADH-dependent nitrite reductase by TnrA and ResDE.

    PubMed

    Nakano, M M; Hoffmann, T; Zhu, Y; Jahn, D

    1998-10-01

    The nitrate and nitrite reductases of Bacillus subtilis have two different physiological functions. Under conditions of nitrogen limitation, these enzymes catalyze the reduction of nitrate via nitrite to ammonia for the anabolic incorporation of nitrogen into biomolecules. They also function catabolically in anaerobic respiration, which involves the use of nitrate and nitrite as terminal electron acceptors. Two distinct nitrate reductases, encoded by narGHI and nasBC, function in anabolic and catabolic nitrogen metabolism, respectively. However, as reported herein, a single NADH-dependent, soluble nitrite reductase encoded by the nasDE genes is required for both catabolic and anabolic processes. The nasDE genes, together with nasBC (encoding assimilatory nitrate reductase) and nasF (required for nitrite reductase siroheme cofactor formation), constitute the nas operon. Data presented show that transcription of nasDEF is driven not only by the previously characterized nas operon promoter but also from an internal promoter residing between the nasC and nasD genes. Transcription from both promoters is activated by nitrogen limitation during aerobic growth by the nitrogen regulator, TnrA. However, under conditions of oxygen limitation, nasDEF expression and nitrite reductase activity were significantly induced. Anaerobic induction of nasDEF required the ResDE two-component regulatory system and the presence of nitrite, indicating partial coregulation of NasDEF with the respiratory nitrate reductase NarGHI during nitrate respiration. PMID:9765565

  5. Nitrogen and Oxygen Regulation of Bacillus subtilis nasDEF Encoding NADH-Dependent Nitrite Reductase by TnrA and ResDE

    PubMed Central

    Nakano, Michiko M.; Hoffmann, Tamara; Zhu, Yi; Jahn, Dieter

    1998-01-01

    The nitrate and nitrite reductases of Bacillus subtilis have two different physiological functions. Under conditions of nitrogen limitation, these enzymes catalyze the reduction of nitrate via nitrite to ammonia for the anabolic incorporation of nitrogen into biomolecules. They also function catabolically in anaerobic respiration, which involves the use of nitrate and nitrite as terminal electron acceptors. Two distinct nitrate reductases, encoded by narGHI and nasBC, function in anabolic and catabolic nitrogen metabolism, respectively. However, as reported herein, a single NADH-dependent, soluble nitrite reductase encoded by the nasDE genes is required for both catabolic and anabolic processes. The nasDE genes, together with nasBC (encoding assimilatory nitrate reductase) and nasF (required for nitrite reductase siroheme cofactor formation), constitute the nas operon. Data presented show that transcription of nasDEF is driven not only by the previously characterized nas operon promoter but also from an internal promoter residing between the nasC and nasD genes. Transcription from both promoters is activated by nitrogen limitation during aerobic growth by the nitrogen regulator, TnrA. However, under conditions of oxygen limitation, nasDEF expression and nitrite reductase activity were significantly induced. Anaerobic induction of nasDEF required the ResDE two-component regulatory system and the presence of nitrite, indicating partial coregulation of NasDEF with the respiratory nitrate reductase NarGHI during nitrate respiration. PMID:9765565

  6. An Integrated Gate Turnaround Management Concept Leveraging Big Data Analytics for NAS Performance Improvements

    NASA Technical Reports Server (NTRS)

    Chung, William W.; Ingram, Carla D.; Ahlquist, Douglas Kurt; Chachad, Girish H.

    2016-01-01

    "Gate Turnaround" plays a key role in the National Air Space (NAS) gate-to-gate performance by receiving aircraft when they reach their destination airport, and delivering aircraft into the NAS upon departing from the gate and subsequent takeoff. The time spent at the gate in meeting the planned departure time is influenced by many factors and often with considerable uncertainties. Uncertainties such as weather, early or late arrivals, disembarking and boarding passengers, unloading/reloading cargo, aircraft logistics/maintenance services and ground handling, traffic in ramp and movement areas for taxi-in and taxi-out, and departure queue management for takeoff are likely encountered on the daily basis. The Integrated Gate Turnaround Management (IGTM) concept is leveraging relevant historical data to support optimization of the gate operations, which include arrival, at the gate, departure based on constraints (e.g., available gates at the arrival, ground crew and equipment for the gate turnaround, and over capacity demand upon departure), and collaborative decision-making. The IGTM concept provides effective information services and decision tools to the stakeholders, such as airline dispatchers, gate agents, airport operators, ramp controllers, and air traffic control (ATC) traffic managers and ground controllers to mitigate uncertainties arising from both nominal and off-nominal airport gate operations. IGTM will provide NAS stakeholders customized decision making tools through a User Interface (UI) by leveraging historical data (Big Data), net-enabled Air Traffic Management (ATM) live data, and analytics according to dependencies among NAS parameters for the stakeholders to manage and optimize the NAS performance in the gate turnaround domain. The application will give stakeholders predictable results based on the past and current NAS performance according to selected decision trees through the UI. The predictable results are generated based on analysis of the

  7. Ubiquity and diversity of heterotrophic bacterial nasA genes in diverse marine environments.

    PubMed

    Jiang, Xuexia; Dang, Hongyue; Jiao, Nianzhi

    2015-01-01

    Nitrate uptake by heterotrophic bacteria plays an important role in marine N cycling. However, few studies have investigated the diversity of environmental nitrate assimilating bacteria (NAB). In this study, the diversity and biogeographical distribution of NAB in several global oceans and particularly in the western Pacific marginal seas were investigated using both cultivation and culture-independent molecular approaches. Phylogenetic analyses based on 16S rRNA and nasA (encoding the large subunit of the assimilatory nitrate reductase) gene sequences indicated that the cultivable NAB in South China Sea belonged to the α-Proteobacteria, γ-Proteobacteria and CFB (Cytophaga-Flavobacteria-Bacteroides) bacterial groups. In all the environmental samples of the present study, α-Proteobacteria, γ-Proteobacteria and Bacteroidetes were found to be the dominant nasA-harboring bacteria. Almost all of the α-Proteobacteria OTUs were classified into three Roseobacter-like groups (I to III). Clone library analysis revealed previously underestimated nasA diversity; e.g. the nasA gene sequences affiliated with β-Proteobacteria, ε-Proteobacteria and Lentisphaerae were observed in the field investigation for the first time, to the best of our knowledge. The geographical and vertical distributions of seawater nasA-harboring bacteria indicated that NAB were highly diverse and ubiquitously distributed in the studied marginal seas and world oceans. Niche adaptation and separation and/or limited dispersal might mediate the NAB composition and community structure in different water bodies. In the shallow-water Kueishantao hydrothermal vent environment, chemolithoautotrophic sulfur-oxidizing bacteria were the primary NAB, indicating a unique nitrate-assimilating community in this extreme environment. In the coastal water of the East China Sea, the relative abundance of Alteromonas and Roseobacter-like nasA gene sequences responded closely to algal blooms, indicating that NAB may be

  8. Ubiquity and Diversity of Heterotrophic Bacterial nasA Genes in Diverse Marine Environments

    PubMed Central

    Jiang, Xuexia; Dang, Hongyue; Jiao, Nianzhi

    2015-01-01

    Nitrate uptake by heterotrophic bacteria plays an important role in marine N cycling. However, few studies have investigated the diversity of environmental nitrate assimilating bacteria (NAB). In this study, the diversity and biogeographical distribution of NAB in several global oceans and particularly in the western Pacific marginal seas were investigated using both cultivation and culture-independent molecular approaches. Phylogenetic analyses based on 16S rRNA and nasA (encoding the large subunit of the assimilatory nitrate reductase) gene sequences indicated that the cultivable NAB in South China Sea belonged to the α-Proteobacteria, γ-Proteobacteria and CFB (Cytophaga-Flavobacteria-Bacteroides) bacterial groups. In all the environmental samples of the present study, α-Proteobacteria, γ-Proteobacteria and Bacteroidetes were found to be the dominant nasA-harboring bacteria. Almost all of the α-Proteobacteria OTUs were classified into three Roseobacter-like groups (I to III). Clone library analysis revealed previously underestimated nasA diversity; e.g. the nasA gene sequences affiliated with β-Proteobacteria, ε-Proteobacteria and Lentisphaerae were observed in the field investigation for the first time, to the best of our knowledge. The geographical and vertical distributions of seawater nasA-harboring bacteria indicated that NAB were highly diverse and ubiquitously distributed in the studied marginal seas and world oceans. Niche adaptation and separation and/or limited dispersal might mediate the NAB composition and community structure in different water bodies. In the shallow-water Kueishantao hydrothermal vent environment, chemolithoautotrophic sulfur-oxidizing bacteria were the primary NAB, indicating a unique nitrate-assimilating community in this extreme environment. In the coastal water of the East China Sea, the relative abundance of Alteromonas and Roseobacter-like nasA gene sequences responded closely to algal blooms, indicating that NAB may be

  9. Estudo em microondas do aprisionamento e precipitação de elétrons em explosões solares

    NASA Astrophysics Data System (ADS)

    Rosal, A. C.; Costa, J. E. R.

    2003-08-01

    Uma explosão solar é uma variação rápida e intensa do brilho que ocorre nas chamadas regiões ativas da atmosfera, constituídas por um plasma magnetizado com intensa indução magnética. Os modelos de explosões solares atuais, discutidos na literatura, apresentam características de aprisionamento e precipitação de elétrons em ambientes magnéticos simplificados. Neste trabalho, nos propusemos a separar a emissão dos elétrons aprisionados da emissão dos elétrons em precipitação apenas a partir da emissão em microondas, melhorando portanto o controle sobre o conjunto de parâmetros inferidos. A emissão em microondas da população em precipitação é bastante fraca e portanto da nossa base de dados de 130 explosões observadas pelo Rádio Polarímetro de Nobeyama, em sete freqüências, apenas para 32 foi possível separar as duas componentes de emissão com uma boa razão sinal/ruído. A partir de estudos das escalas de tempo das emissões devidas à variação gradual da emissão no aprisionamento e da variação rápida da emissão dos elétrons em precipitação foi possível obter a separação utilizando um filtro temporal nas emissões resultantes. Em nossa análise destas explosões estudamos os espectros girossincrotrônicos da emissão gradual, a qual associamos provir do topo dos arcos magnéticos e da emissão de variação rápida associada aos elétrons em precipitação. Estes espectros foram calculados e dos quais inferimos que a indução magnética efetiva do topo e dos pés foi em média, Btopo = 236 G e Bpés = 577 G, inferidas das freqüências de pico dos espectros em ntopo = 11,8 GHz e npés = 14,6 GHz com leve anisotropia (pequeno alargamento espectral). O índice espectral da distribuição não-térmica de elétrons d, inferido do índice espectral de fótons da emissão em regime opticamente fino, foi de dtopo = 3,3 e dpés = 3,9. Estes parâmetros são típicos da maioria das análises realizadas em ambiente único de

  10. First-principle natural band alignment of GaN / dilute-As GaNAs alloy

    SciTech Connect

    Tan, Chee-Keong Tansu, Nelson

    2015-01-15

    Density functional theory (DFT) calculations with the local density approximation (LDA) functional are employed to investigate the band alignment of dilute-As GaNAs alloys with respect to the GaN alloy. Conduction and valence band positions of dilute-As GaNAs alloy with respect to the GaN alloy on an absolute energy scale are determined from the combination of bulk and surface DFT calculations. The resulting GaN / GaNAs conduction to valence band offset ratio is found as approximately 5:95. Our theoretical finding is in good agreement with experimental observation, indicating the upward movements of valence band at low-As content dilute-As GaNAs are mainly responsible for the drastic reduction of the GaN energy band gap. In addition, type-I band alignment of GaN / GaNAs is suggested as a reasonable approach for future device implementation with dilute-As GaNAs quantum well, and possible type-II quantum well active region can be formed by using InGaN / dilute-As GaNAs heterostructure.

  11. Moth eye antireflection coated GaInP/GaAs/GaInNAs solar cell

    NASA Astrophysics Data System (ADS)

    Aho, Arto; Tommila, Juha; Tukiainen, Antti; Polojärvi, Ville; Niemi, Tapio; Guina, Mircea

    2014-09-01

    The performance of a GaInP/GaAs/GaInNAs solar cell incorporating AlInP moth eye antireflection coating is reported and compared with the performance of a similar cell comprising TiO2/SiO2 antireflection coating. The moth eye coating exhibits an average reflectance of only 2% within the spectral range from 400 nm to 1600 nm. EQE measurements revealed absorption-related losses in the AlInP moth eye coating at wavelengths below 510 nm. Short wavelength absorption decreases the current generation in the top GaInP junction by 10%. Despite the absorption losses, the moth eye patterned GaInP/GaAs/GaInNAs solar cell exhibited higher current generation under AM1.5G real sun illumination.

  12. Influence of N cluster states on band dispersion in GaInNAs quantum wells

    NASA Astrophysics Data System (ADS)

    Healy, S. B.; Lindsay, A.; O'Reilly, E. P.

    2006-05-01

    We use a modified band-anticrossing (BAC) model to investigate the band dispersion in a GaNxAs1-x/AlGaAs quantum well (QW) as a function of hydrostatic pressure. The band edge mass increases considerably more quickly with pressure than in the case of a GaAs/AlGaAs QW, and the subband separation also decreases significantly. We predict that the strong anticrossing interaction between the GaAs host conduction band and isolated N levels will inhibit tunnelling through the QW for a range of energy above the isolated N levels. The energy of N resonant states depends strongly on details of the local environment, giving a broader calculated distribution of N states in GaInNAs compared to GaNAs.

  13. Enhanced-Depletion-Width GaInNAs Solar Cells Grown by Molecular-Beam Epitaxy

    SciTech Connect

    Ptak, A. J.; Friedman, D. J.

    2005-01-01

    The 3-junction, GaInP2/GaAs/Ge solar cell is a non-optimized structure due to excess light falling on the Ge junction. Because of this, a fourth junction inserted between the GaAs and Ge subcells could use the excess light and provide an increase in device efficiency. Unfortunately, the leading candidate material, GaInNAs, suffers from very low minority-carrier diffusion lengths compared to its parent compound, GaAs. These low diffusion lengths do not allow for the collection of adequate current to keep the overall 4-junction structure current matched. If the currents generated from the GaInNAs subcell are increased, the possibility exists for practical efficiencies of greater than 40% from this structure.

  14. The temperature dependence of atomic incorporation characteristics in growing GaInNAs films

    SciTech Connect

    Li, Jingling; Gao, Fangliang; Wen, Lei; Zhou, Shizhong; Zhang, Shuguang E-mail: msgli@scut.edu.cn; Li, Guoqiang E-mail: msgli@scut.edu.cn

    2015-02-07

    We have systematically studied the temperature dependence of incorporation characteristics of nitrogen (N) and indium (In) in growing GaInNAs films. With the implementation of Monte-Carlo simulation, the low N adsorption energy (−0.10 eV) is demonstrated. To understand the atomic incorporation mechanism, temperature dependence of interactions between Group-III and V elements are subsequently discussed. We find that the In incorporation behaviors rather than that of N are more sensitive to the T{sub g}, which can be experimentally verified by exploring the compositional modulation and structural changes of the GaInNAs films by means of high-resolution X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope, and secondary ion mass spectroscopy.

  15. NAS technical summaries. Numerical aerodynamic simulation program, March 1992 - February 1993

    NASA Technical Reports Server (NTRS)

    1994-01-01

    NASA created the Numerical Aerodynamic Simulation (NAS) Program in 1987 to focus resources on solving critical problems in aeroscience and related disciplines by utilizing the power of the most advanced supercomputers available. The NAS Program provides scientists with the necessary computing power to solve today's most demanding computational fluid dynamics problems and serves as a pathfinder in integrating leading-edge supercomputing technologies, thus benefitting other supercomputer centers in government and industry. The 1992-93 operational year concluded with 399 high-speed processor projects and 91 parallel projects representing NASA, the Department of Defense, other government agencies, private industry, and universities. This document provides a glimpse at some of the significant scientific results for the year.

  16. Object-Oriented Implementation of the NAS Parallel Benchmarks using Charm++

    NASA Technical Reports Server (NTRS)

    Krishnan, Sanjeev; Bhandarkar, Milind; Kale, Laxmikant V.

    1996-01-01

    This report describes experiences with implementing the NAS Computational Fluid Dynamics benchmarks using a parallel object-oriented language, Charm++. Our main objective in implementing the NAS CFD kernel benchmarks was to develop a code that could be used to easily experiment with different domain decomposition strategies and dynamic load balancing. We also wished to leverage the object-orientation provided by the Charm++ parallel object-oriented language, to develop reusable abstractions that would simplify the process of developing parallel applications. We first describe the Charm++ parallel programming model and the parallel object array abstraction, then go into detail about each of the Scalar Pentadiagonal (SP) and Lower/Upper Triangular (LU) benchmarks, along with performance results. Finally we conclude with an evaluation of the methodology used.

  17. Large-scale structural analysis: The structural analyst, the CSM Testbed and the NAS System

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.; Mccleary, Susan L.; Macy, Steven C.; Aminpour, Mohammad A.

    1989-01-01

    The Computational Structural Mechanics (CSM) activity is developing advanced structural analysis and computational methods that exploit high-performance computers. Methods are developed in the framework of the CSM testbed software system and applied to representative complex structural analysis problems from the aerospace industry. An overview of the CSM testbed methods development environment is presented and some numerical methods developed on a CRAY-2 are described. Selected application studies performed on the NAS CRAY-2 are also summarized.

  18. Functional Requirements Document for HALE UAS Operations in the NAS: Step 1. Version 3

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The purpose of this Functional Requirements Document (FRD) is to compile the functional requirements needed to achieve the Access 5 Vision of "operating High Altitude, Long Endurance (HALE) Unmanned Aircraft Systems (UAS) routinely, safely, and reliably in the national airspace system (NAS)" for Step 1. These functional requirements could support the development of a minimum set of policies, procedures and standards by the Federal Aviation Administration (FAA) and various standards organizations. It is envisioned that this comprehensive body of work will enable the FAA to establish and approve regulations to govern safe operation of UAS in the NAS on a routine or daily "file and fly" basis. The approach used to derive the functional requirements found within this FRD was to decompose the operational requirements and objectives identified within the Access 5 Concept of Operations (CONOPS) into the functions needed to routinely and safely operate a HALE UAS in the NAS. As a result, four major functional areas evolved to enable routine and safe UAS operations for an on-demand basis in the NAS. These four major functions are: Aviate, Navigate, Communicate, and Avoid Hazards. All of the functional requirements within this document can be directly traceable to one of these four major functions. Some functions, however, are traceable to several, or even all, of these four major functions. These cross-cutting functional requirements support the "Command / Control: function as well as the "Manage Contingencies" function. The requirements associated to these high-level functions and all of their supporting low-level functions are addressed in subsequent sections of this document.

  19. Applications Performance Under MPL and MPI on NAS IBM SP2

    NASA Technical Reports Server (NTRS)

    Saini, Subhash; Simon, Horst D.; Lasinski, T. A. (Technical Monitor)

    1994-01-01

    On July 5, 1994, an IBM Scalable POWER parallel System (IBM SP2) with 64 nodes, was installed at the Numerical Aerodynamic Simulation (NAS) Facility Each node of NAS IBM SP2 is a "wide node" consisting of a RISC 6000/590 workstation module with a clock of 66.5 MHz which can perform four floating point operations per clock with a peak performance of 266 Mflop/s. By the end of 1994, 64 nodes of IBM SP2 will be upgraded to 160 nodes with a peak performance of 42.5 Gflop/s. An overview of the IBM SP2 hardware is presented. The basic understanding of architectural details of RS 6000/590 will help application scientists the porting, optimizing, and tuning of codes from other machines such as the CRAY C90 and the Paragon to the NAS SP2. Optimization techniques such as quad-word loading, effective utilization of two floating point units, and data cache optimization of RS 6000/590 is illustrated, with examples giving performance gains at each optimization step. The conversion of codes using Intel's message passing library NX to codes using native Message Passing Library (MPL) and the Message Passing Interface (NMI) library available on the IBM SP2 is illustrated. In particular, we will present the performance of Fast Fourier Transform (FFT) kernel from NAS Parallel Benchmarks (NPB) under MPL and MPI. We have also optimized some of Fortran BLAS 2 and BLAS 3 routines, e.g., the optimized Fortran DAXPY runs at 175 Mflop/s and optimized Fortran DGEMM runs at 230 Mflop/s per node. The performance of the NPB (Class B) on the IBM SP2 is compared with the CRAY C90, Intel Paragon, TMC CM-5E, and the CRAY T3D.

  20. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project

    NASA Technical Reports Server (NTRS)

    Griner, James H.

    2013-01-01

    NASA's UAS Integration in the NAS project, has partnered with Rockwell Collins to develop a concept Control and Non-Payload Communication system prototype radio, operating on recently allocated UAS frequency spectrum bands. The prototype radio will be used to validate initial proposed performance requirements for UAS control communications. This presentation will give an overview of the current status of the design, development, and flight test planning for this prototype radio.

  1. Carrier trapping and escape times in p-i-n GaInNAs MQW structures

    PubMed Central

    2014-01-01

    We used a semi-classical model to describe carrier capture into and thermionic escape from GaInNAs/GaAs multiple quantum wells (MQWs) situated within the intrinsic region of a GaAs p-i-n junction. The results are used to explain photocurrent oscillations with applied bias observed in these structures, in terms of charge accumulation and resonance tunnelling. PMID:24417767

  2. NAS Parallel Benchmarks I/O Version 2.4. 2.4

    NASA Technical Reports Server (NTRS)

    Wong, Parkson; VanderWijngaart, Rob F.; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    We describe a benchmark problem, based on the Block-Tridiagonal (BT) problem of the NAS Parallel Benchmarks (NPB), which is used to test the output capabilities of high-performance computing systems, especially parallel systems. We also present a source code implementation of the benchmark, called NPBIO2.4-MPI, based on the MPI implementation of NPB, using a variety of ways to write the computed solutions to file.

  3. Nitrogen incorporation effects on gain properties of GaInNAs lasers : experiment and theory.

    SciTech Connect

    Thranhardt, A.; Mawst, L. J.; Hader, J.; Schlichenmaier, C.; Tansu, N.; Yeh, J. -Y.; Belenky, G.; Chow, Weng Wah; Shterengas, L.; Moloney, Jerome V.; Koch, S. W.; Kuznetsova, I.

    2005-05-01

    Gain properties of GaInNAs lasers with different nitrogen concentrations in the quantum wells are investigated experimentally and theoretically. Whereas nitrogen incorporation induces appreciable modifications in the spectral extension and the carrier density dependence of the gain, it is found that the linewidth enhancement factor is reduced by inclusion of nitrogen, but basically unaffected by different nitrogen content due to the balancing between gain and index changes.

  4. Structural properties of GaNAs nanowires probed by micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Filippov, S.; Ishikawa, F.; Chen, W. M.; Buyanova, I. A.

    2016-02-01

    GaNAs-based nanowires (NWs) form a novel material system of potential importance for applications in advanced optoelectronic and photonic devices, thanks to the advantages provided by band-structure engineering, one-dimensional architecture and the possibility to combine them with mainstream silicon technology. In this work we utilize the micro-Raman scattering technique to systematically study the structural properties of such GaAs/GaNAs core/shell NW structures grown by molecular beam epitaxy on a Si substrate. It is shown that the employed one-dimensional architecture allows the fabrication of a GaNAs shell with a low degree of alloy disorder and weak residual strain, at least within the studied range of nitrogen (N) compositions [N] < 0.6%. Raman scattering by the GaAs-like and GaN-like phonons is found to be enhanced when the excitation energy approaches the E+ transition energy. Since this effect is found to be more pronounced for the GaN-like phonons, the involved intermediate states are concluded to be localized in proximity to N impurities, i.e. they likely represent N-related cluster states located in proximity to E+.

  5. Effects of Bismuth on Wide-Depletion-Width GaInNAs Solar Cells

    SciTech Connect

    Ptak, A. J.; France, R.; Jiang, C.-S.; Reedy, R. C.

    2008-05-01

    GaInNAs solar cells could be useful in next-generation multijunction solar cells if issues surrounding low photocurrents and photovoltages are surmounted. Wide-depletion-width devices generate significant photocurrent using a p-i-n structure grown by molecular beam epitaxy, but these depletion widths are only realized in a region of parameter space that leads to rough surface morphologies. Here, bismuth is explored as a surfactant for the growth of GaInNAs solar cells. Very low fluxes of Bi are effective at maintaining smooth surfaces, even at high growth temperatures and In contents. However, Bi also increases the net donor concentration in these materials, manifested in our n-on-p device structures as a pn-junction that moves deeper into the base layer with increasing Bi fluxes. Quantum efficiency modeling and scanning kelvin probe microscopy measurements confirm the type conversion of the base layer from p type to n type. Bi incorporation in GaAsBi samples shows signs of surface segregation, leading to a finite buildup time, and this effect may lead to slow changes in the electrical properties of the GaInNAs(Bi) devices. Bi also appears to create a defect level, although this defect level is not deleterious enough to increase the dark current in the devices.

  6. NAS technical summaries: Numerical aerodynamic simulation program, March 1991 - February 1992

    NASA Technical Reports Server (NTRS)

    1992-01-01

    NASA created the Numerical Aerodynamic Simulation (NAS) Program in 1987 to focus resources on solving critical problems in aeroscience and related disciplines by utilizing the power of the most advanced supercomputers available. The NAS Program provides scientists with the necessary computing power to solve today's most demanding computational fluid dynamics problems and serves as a pathfinder in integrating leading-edge supercomputing technologies, thus benefiting other supercomputer centers in Government and industry. This report contains selected scientific results from the 1991-92 NAS Operational Year, March 4, 1991 to March 3, 1992, which is the fifth year of operation. During this year, the scientific community was given access to a Cray-2 and a Cray Y-MP. The Cray-2, the first generation supercomputer, has four processors, 256 megawords of central memory, and a total sustained speed of 250 million floating point operations per second. The Cray Y-MP, the second generation supercomputer, has eight processors and a total sustained speed of one billion floating point operations per second. Additional memory was installed this year, doubling capacity from 128 to 256 megawords of solid-state storage-device memory. Because of its higher performance, the Cray Y-MP delivered approximately 77 percent of the total number of supercomputer hours used during this year.

  7. Determination of composition and energy gaps of GaInNAsSb layers grown by MBE

    NASA Astrophysics Data System (ADS)

    Aho, A.; Korpijärvi, V.-M.; Isoaho, R.; Malinen, P.; Tukiainen, A.; Honkanen, M.; Guina, M.

    2016-03-01

    We present a method to accurately determine the composition of GaInNAsSb heterostructures and a modified band anti-crossing model to calculate the corresponding bandgaps. The composition determination method is based on combining x-ray diffractometry and energy dispersive x-ray spectroscopy measurements. The modified band anti-crossing model was derived from the model known for GaInNAs and using band-gap composition relations for GaInAs, GaInSb, InAsSb and GaAsSb. The model parameters were defined by fitting with experimental bandgap data retrieved from photoluminescence. For validation and data fitting we used experimental samples with N composition in the range of 0-0.06, In composition from 0 to 0.17, and Sb composition in the range of 0-0.08. All samples were thermally annealed to minimize the band gap shift caused by the short range ordering effects in GaInNAsSb crystal. The modified model yields an excellent fit to the experimental band gap data with an accuracy of ~20 meV, and is a practical tool for designing, fabricating and analyzing optoelectronics devices.

  8. Estudo comparativo entre estrelas centrais de nebulosas planetárias deficientes em hidrogênio

    NASA Astrophysics Data System (ADS)

    Marcolino, W. L. F.; de Araújo, F. X.

    2003-08-01

    Apresentamos neste trabalho o resultado de um estudo das principais características espectrais das estrelas centrais de nebulosas planetárias (ECNP) deficientes em hidrogênio. A origem e a evolução dessas estrelas ainda constitui um problema em aberto na evolução estelar. Geralmente esses objetos são divididos em [WCE], [WCL] e [WELS]. Os tipos [WCE] e [WCL] apresentam um espectro típico de uma estrela Wolf-Rayet carbonada de população I e as [WELS] apresentam linhas fracas de carbono e oxigênio em emissão. Existem evidências que apontam a seguinte sequência evolutiva : [WCL] = > [WCE] = > [WELS] = > PG 1159 (pré anã-branca). No entanto, tal cenário apresenta falhas como por exemplo a falta de ECNP entre os tipos [WCL] e [WCE]. Baseados em uma amostra de 24 objetos obtida no telescópio de 1.52m em La Silla, Chile (acordo ESO/ON), ao longo do ano 2000, apresentamos os resultados da comparação das larguras equivalentes de diversas linhas relevantes entre os tipos [WCL], [WCE] e [WELS]. Verificamos que nossos dados estão de acordo com a sequência evolutiva. Baseado nas linhas de C IV, conseguimos dividir pela primeira vez as [WELS] em dois grupos principais. Além disso, os dados reforçam a afirmação de que as [WCE] são as estrelas que possuem a maior temperatura entre as ECNP deficientes em hidrogênio. Discutimos ainda, a escassez de dados disponíveis na literatura e a necessidade da obtenção de parametros físicos para estes objetos.

  9. Effect of antimony on the deep-level traps in GaInNAsSb thin films

    SciTech Connect

    Islam, Muhammad Monirul Miyashita, Naoya; Ahsan, Nazmul; Okada, Yoshitaka; Sakurai, Takeaki; Akimoto, Katsuhiro

    2014-09-15

    Admittance spectroscopy has been performed to investigate the effect of antimony (Sb) on GaInNAs material in relation to the deep-level defects in this material. Two electron traps, E1 and E2 at an energy level 0.12 and 0.41 eV below the conduction band (E{sub C}), respectively, were found in undoped GaInNAs. Bias-voltage dependent admittance confirmed that E1 is an interface-type defect being spatially localized at the GaInNAs/GaAs interface, while E2 is a bulk-type defect located around mid-gap of GaInNAs layer. Introduction of Sb improved the material quality which was evident from the reduction of both the interface and bulk-type defects.

  10. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project. NASA Contributions to the SARP WC Definition

    NASA Technical Reports Server (NTRS)

    Randall, Debra K.; Consiglio, Maria Cristina; Santiago, Confesor

    2014-01-01

    To better inform sense and avoid research needs and to understand ongoing investigation of potential solutions that ultimately lead to the assisting the FAA with their Congressional mandate to fly UAS in the NAS.

  11. Anisotropic Lattice Deformation of InAs Self-Assembled Quantum Dots Embedded in GaNAs Strain Compensating Layers

    NASA Astrophysics Data System (ADS)

    Matsumura, N.; Muto, S.; Ganapathy, S.; Suemune, I.; Numata, K.; Yabuta, K.

    2006-01-01

    Lattice deformations of InAs self-assembled quantum dots, which were grown on (001)GaAs substrates and embedded in GaNAs strain compensating layers (SCLs), were examined with an ion-channeling method in Rutherford backscattering spectrometry. The channeling experiments demonstrated that the increase of the nitrogen concentrations in the GaNAs SCLs caused the indium lattice displacements along the [001] growth direction while those parallel to the (001) crystal plane were kept unchanged.

  12. 75 FR 28610 - Draft EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ...EPA is announcing a 90-day public comment period for the external review draft entitled, ``EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments'' (EPA/600/R- 10/038A). This draft report responds to the key recommendations and comments included in the National Academy of Sciences (NAS) 2006 report. In addition, it includes new analyses on potential human......

  13. emGain: Determination of EM gain of CCD

    NASA Astrophysics Data System (ADS)

    Daigle, Olivier; Carignan, Claude; Blais-Ouellette, Sebastien

    2012-01-01

    The determination of the EM gain of the CCD is best done by fitting the histogram of many low-light frames. Typically, the dark+CIC noise of a 30ms frame itself is a sufficient amount of signal to determine accurately the EM gain with about 200 512x512 frames. The IDL code emGain takes as an input a cube of frames and fit the histogram of all the pixels with the EM stage output probability function. The function returns the EM gain of the frames as well as the read-out noise and the mean signal level of the frames.

  14. The CAS-NAS forum for new leaders in space science

    NASA Astrophysics Data System (ADS)

    Smith, David H.

    The space science community is thoroughly international, with numerous nations now capable of launching scientific payloads into space either independently or in concert with others. As such, it is important for national space-science advisory groups to engage with like-minded groups in other spacefaring nations. The Space Studies Board of the US National Academy of Sciences' (NAS') National Research Council has provided scientific and technical advice to NASA for more than 50 years. Over this period, the Board has developed important multilateral and bilateral partnerships with space scientists around the world. The primary multilateral partner is COSPAR, for which the Board serves as the US national committee. The Board's primary bilateral relationship is with the European Science Foundation’s European Space Science Committee. Burgeoning Chinese space activities have resulted in several attempts in the past decade to open a dialogue between the Board and space scientists in China. On each occasion, the external political environment was not conducive to success. The most recent efforts to engage the Chinese space researchers began in 2011 and have proved particularly successful. Although NASA is currently prohibited from engaging in bilateral activities with China, the Board has established a fruitful dialogue with its counterpart in the Chinese Academy of Sciences (CAS). A joint NAS-CAS activity, the Forum for New Leaders in Space Science, has been established to provide opportunities for a highly select group of young space scientists from China and the United States to discuss their research activities in an intimate and collegial environment at meetings to be held in both nations. The presentation will describe the current state of US-China space relations, discuss the goals of the joint NAS-CAS undertaking and report on the activities at the May, 2014, Forum in Beijing and the planning for the November, 2014, Forum in Irvine, California.

  15. UAS Integration Into the NAS: An Examination of Baseline Compliance in the Current Airspace System

    NASA Technical Reports Server (NTRS)

    Fern, Lisa; Kenny, Caitlin A.; Shively, Robert J.; Johnson, Walter

    2012-01-01

    As a result of the FAA Modernization and Reform Act of 2012, Unmanned Aerial Systems (UAS) are expected to be integrated into the National Airspace System (NAS) by 2015. Several human factors challenges need to be addressed before UAS can safely and routinely fly in the NAS with manned aircraft. Perhaps the most significant challenge is for the UAS to be non-disruptive to the air traffic management system. Another human factors challenge is how to provide UAS pilots with intuitive traffic information in order to support situation awareness (SA) of their airspace environment as well as a see-and-avoid capability comparable to manned aircraft so that a UAS pilot could safely maneuver the aircraft to maintain separation and collision avoidance if necessary. A simulation experiment was conducted to examine baseline compliance of UAS operations in the current airspace system. Researchers also examined the effects of introducing a Cockpit Situation Display (CSD) into a UAS Ground Control Station (GCS) on UAS pilot performance, workload and situation awareness while flying in a positively controlled sector. Pilots were tasked with conducting a highway patrol police mission with a Medium Altitude Long Endurance (MALE) UAS in L.A. Center airspace with two mission objectives: 1) to reroute the UAS when issued new instructions from their commander, and 2) to communicate with Air Traffic Control (ATC) to negotiate flight plan changes and respond to vectoring and altitude change instructions. Objective aircraft separation data, workload ratings, SA data, and subjective ratings regarding UAS operations in the NAS were collected. Results indicate that UAS pilots were able to comply appropriately with ATC instructions. In addition, the introduction of the CSD improved pilot SA and reduced workload associated with UAS and ATC interactions.

  16. High power frequency doubled GaInNAs semiconductor disk laser emitting at 615 nm.

    PubMed

    Härkönen, Antti; Rautiainen, Jussi; Guina, Mircea; Konttinen, Janne; Tuomisto, Pietari; Orsila, Lasse; Pessa, Markus; Okhotnikov, Oleg G

    2007-03-19

    We report on an optically-pumped intracavity frequency doubled GaInNAs/GaAs -based semiconductor disk laser emitting around 615 nm. The laser operates at fundamental wavelength of 1230 nm and incorporates a BBO crystal for light conversion to the red wavelength. Maximum output power of 172 mW at 615 nm was achieved from a single output. Combined power from two outputs was 320 mW. The wavelength of visible emission could be tuned by 4.5 nm using a thin glass etalon inside the cavity. PMID:19532562

  17. The OpenMP Implementation of NAS Parallel Benchmarks and its Performance

    NASA Technical Reports Server (NTRS)

    Jin, Hao-Qiang; Frumkin, Michael; Yan, Jerry

    1999-01-01

    As the new ccNUMA architecture became popular in recent years, parallel programming with compiler directives on these machines has evolved to accommodate new needs. In this study, we examine the effectiveness of OpenMP directives for parallelizing the NAS Parallel Benchmarks. Implementation details will be discussed and performance will be compared with the MPI implementation. We have demonstrated that OpenMP can achieve very good results for parallelization on a shared memory system, but effective use of memory and cache is very important.

  18. Communication Improvement for the LU NAS Parallel Benchmark: A Model for Efficient Parallel Relaxation Schemes

    NASA Technical Reports Server (NTRS)

    Yarrow, Maurice; VanderWijngaart, Rob; Kutler, Paul (Technical Monitor)

    1997-01-01

    The first release of the MPI version of the LU NAS Parallel Benchmark (NPB2.0) performed poorly compared to its companion NPB2.0 codes. The later LU release (NPB2.1 & 2.2) runs up to two and a half times faster, thanks to a revised point access scheme and related communications scheme. The new scheme sends substantially fewer messages. is cache "friendly", and has a better load balance. We detail the, observations and modifications that resulted in this efficiency improvement, and show that the poor behavior of the original code resulted from deriving a message passing scheme from an algorithm originally devised for a vector architecture.

  19. A Framework for Safe Integration of Small UAS Into the NAS

    NASA Technical Reports Server (NTRS)

    Logan, Michael J.; Bland, Geoffrey; Murray, Jennifer

    2011-01-01

    This paper discusses a proposed framework for the safe integration of small unmanned aerial systems (sUAS) into the National Airspace System (NAS). The paper examines the potential uses of sUAS to build an understanding of the location and frequency of potential future flight operations based on the future applications of the sUAS systems. The paper then examines the types of systems that would be required to meet the application-level demand to determine classes of platforms and operations. Finally, a framework is proposed for both airworthiness and operations that attempts to balance safety with utility for these important systems.

  20. NAS (Numerical Aerodynamic Simulation Program) technical summaries, March 1989 - February 1990

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Given here are selected scientific results from the Numerical Aerodynamic Simulation (NAS) Program's third year of operation. During this year, the scientific community was given access to a Cray-2 and a Cray Y-MP supercomputer. Topics covered include flow field analysis of fighter wing configurations, large-scale ocean modeling, the Space Shuttle flow field, advanced computational fluid dynamics (CFD) codes for rotary-wing airloads and performance prediction, turbulence modeling of separated flows, airloads and acoustics of rotorcraft, vortex-induced nonlinearities on submarines, and standing oblique detonation waves.

  1. UAS Integration in the NAS Project: Integrated Test and Evaluation (IT&E) Flight Test 3. Revision E

    NASA Technical Reports Server (NTRS)

    Marston, Michael

    2015-01-01

    The desire and ability to fly Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) is of increasing urgency. The application of unmanned aircraft to perform national security, defense, scientific, and emergency management are driving the critical need for less restrictive access by UAS to the NAS. UAS represent a new capability that will provide a variety of services in the government (public) and commercial (civil) aviation sectors. The growth of this potential industry has not yet been realized due to the lack of a common understanding of what is required to safely operate UAS in the NAS. NASA's UAS Integration into the NAS Project is conducting research in the areas of Separation Assurance/Sense and Avoid Interoperability, Human Systems Integration (HSI), and Communication to support reducing the barriers of UAS access to the NAS. This research is broken into two research themes namely, UAS Integration and Test Infrastructure. UAS Integration focuses on airspace integration procedures and performance standards to enable UAS integration in the air transportation system, covering Sense and Avoid (SAA) performance standards, command and control performance standards, and human systems integration. The focus of Test Infrastructure is to enable development and validation of airspace integration procedures and performance standards, including the integrated test and evaluation. In support of the integrated test and evaluation efforts, the Project will develop an adaptable, scalable, and schedulable relevant test environment capable of evaluating concepts and technologies for unmanned aircraft systems to safely operate in the NAS. To accomplish this task, the Project will conduct a series of Human-in-the-Loop and Flight Test activities that integrate key concepts, technologies and/or procedures in a relevant air traffic environment. Each of the integrated events will build on the technical achievements, fidelity and complexity of the previous tests and

  2. Aeronautics Research Mission Directorate Integrated Systems Research Program (ISRP) and UAS Integration in the NAS Project

    NASA Technical Reports Server (NTRS)

    Wolfe, Jean

    2010-01-01

    Program Goal: Conduct research at an integrated system-level on promising concepts and technologies and explore, assess, or demonstrate the benefits in a relevant environment.Criteria for selection of projects for Integrated Systems Research: a) Technology has attained enough maturity in the foundational research program that they merit more in-depth evaluation at an integrated system level in a relevant environment. b) Technologies which systems analysis indicates have the most potential for contributing to the simultaneous attainment of goals. c) Technologies identified through stakeholder input as having potential for simultaneous attainment of goals. d) Research not being done by other government agencies and appropriate for NASA to conduct. e) Budget augmentation. Environmentally Responsible Aviation (ERA) Project Explore and assess new vehicle concepts and enabling technologies through system-level experimentation to simultaneously reduce fuel burn, noise, and emissions Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project Contribute capabilities that reduce technical barriers related to the safety and operational challenges associated with enabling routine UAS access to the NAS Innovative Concepts for Green Aviation (ICGA) Project Spur innovation by offering research opportunities to the broader aeronautics community through peer-reviewed proposals, with a focus on making aviation more eco-friendly. Establish incentive prizes similar to the Centennial Challenges and sponsor innovation demonstrations of selected technologies that show promise of reducing aviation s impact on the environment

  3. InGaN/Dilute-As GaNAs Interface Quantum Well for Red Emitters

    PubMed Central

    Tan, Chee-Keong; Borovac, Damir; Sun, Wei; Tansu, Nelson

    2016-01-01

    The design of InGaN/dilute-As GaNAs interface quantum well (QW) leads to significant redshift in the transition wavelength with improvement in electron-hole wave function overlap and spontaneous emission rate as compared to that of the conventional In0.2Ga0.8N QW. By using self-consistent six-band k·p band formalism, the nitride active region consisting of 30 Å In0.2Ga0.8N and 10 Å GaN0.95As0.05 interface QW leads to 623.52 nm emission wavelength in the red spectral regime. The utilization of 30 Å In0.2Ga0.8N/10 Å GaN0.95As0.05 interface QW also leads to 8.5 times enhancement of spontaneous emission rate attributed by the improvement in electron-hole wavefunction overlap, as compared to that of conventional 30 Å In0.35Ga0.65N QW for red spectral regime. In addition, the transition wavelength of the interface QW is relatively unaffected by the thickness of the dilute-As GaNAs interface layer (beyond 10 Å). The analysis indicates the potential of using interface QW concept in nitride-based light-emitting diodes for long wavelength emission. PMID:26758552

  4. Growth and characterisation of Ga(NAsBi) alloy by metal-organic vapour phase epitaxy

    NASA Astrophysics Data System (ADS)

    Bushell, Z. L.; Ludewig, P.; Knaub, N.; Batool, Z.; Hild, K.; Stolz, W.; Sweeney, S. J.; Volz, K.

    2014-06-01

    This paper summarises results of the epitaxial growth of Ga(NAsBi) by metal-organic vapour phase epitaxy (MOVPE) and the subsequent optical and structural characterisations of the samples. Ga(NAsBi)/GaAs multi-quantum well (MQW) samples are grown at 400 °C and single layers at 450 °C on GaAs (001) substrates. Triethylgallium (TEGa), tertiarybutylarsine (TBAs), trimethylbismuth (TMBi) and unsymmetrical dimethylhydrazine (UDMHy) are used as precursors. Secondary ion mass spectrometry (SIMS) shows that the Bi content is independent of the N content in the alloy. It is found that the N content depends on both UDMHy and TMBi supply during growth. High resolution X-ray diffraction (HR-XRD), scanning transmission electron microscopy (STEM) and atomic force microscopy (AFM) measurements show that samples with good crystalline quality can be realised. For samples containing 1.8% Bi and up to 1.8% N grown at 450 °C, photoreflectance spectroscopy (PR) shows a decrease in the band gap with increasing N content of 141±22 meV/% N.

  5. Web Prep: How to Prepare NAS Reports For Publication on the Web

    NASA Technical Reports Server (NTRS)

    Walatka, Pamela; Balakrishnan, Prithika; Clucas, Jean; McCabe, R. Kevin; Felchle, Gail; Brickell, Cristy

    1996-01-01

    This document contains specific advice and requirements for NASA Ames Code IN authors of NAS reports. Much of the information may be of interest to other authors writing for the Web. WebPrep has a graphic Table of Contents in the form of a WebToon, which simulates a discussion between a scientist and a Web publishing consultant. In the WebToon, Frequently Asked Questions about preparing reports for the Web are linked to relevant text in the body of this document. We also provide a text-only Table of Contents. The text for this document is divided into chapters: each chapter corresponds to one frame of the WebToons. The chapter topics are: converting text to HTML, converting 2D graphic images to gif, creating imagemaps and tables, converting movie and audio files to Web formats, supplying 3D interactive data, and (briefly) JAVA capabilities. The last chapter is specifically for NAS staff authors. The Glossary-Index lists web related words and links to topics covered in the main text.

  6. Growth optimization and optical properties of AlGaNAs alloys

    SciTech Connect

    Kolhatkar, Gitanjali; Boucherif, Abderraouf; Aimez, Vincent; Arès, Richard; Valdivia, Christopher E.; Wallace, Steven G.; Fafard, Simon

    2014-04-28

    The effect of Al on the surface morphology of chemical beam epitaxy grown AlGaNAs alloys is studied. Pits attributed to N clustering appearing on the dilute nitride surface become smaller, denser, and more uniformly distributed in the presence of Al. This reveals that the introduction of Al results in more homogenous N atoms spatial distribution. A growth temperature study reveals the formation of 3D structures at high temperature due to phase separation. The density of these structures decreases, while their diameter and height increase when the temperature is raised from 380 °C to 565 °C. At growth temperatures in the 380–420 °C range, the phase separation is suppressed and the growth mode is 2D. At 420 °C, the N incorporation is also maximized, making it the optimum temperature. The absorption coefficient and the bandgap of AlGaNAs alloys are extracted from transmittance measurement. A good agreement is obtained between the experimentally measured bandgap and the theoretical values calculated using the band anticrossing model. A bandgap as low as 1.22 eV was reached using Al and N concentrations of ∼15% and ∼3.4%, respectively.

  7. The EM Earthquake Precursor

    NASA Astrophysics Data System (ADS)

    Jones, K. B., II; Saxton, P. T.

    2013-12-01

    Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After the 1989 Loma Prieta Earthquake, American earthquake investigators predetermined magnetometer use and a minimum earthquake magnitude necessary for EM detection. This action was set in motion, due to the extensive damage incurred and public outrage concerning earthquake forecasting; however, the magnetometers employed, grounded or buried, are completely subject to static and electric fields and have yet to correlate to an identifiable precursor. Secondly, there is neither a networked array for finding any epicentral locations, nor have there been any attempts to find even one. This methodology needs dismissal, because it is overly complicated, subject to continuous change, and provides no response time. As for the minimum magnitude threshold, which was set at M5, this is simply higher than what modern technological advances have gained. Detection can now be achieved at approximately M1, which greatly improves forecasting chances. A propagating precursor has now been detected in both the field and laboratory. Field antenna testing conducted outside the NE Texas town of Timpson in February, 2013, detected three strong EM sources along with numerous weaker signals. The antenna had mobility, and observations were noted for recurrence, duration, and frequency response. Next, two

  8. Comparison of 250 MHz R10K Origin 2000 and 400 MHz Origin 2000 Using NAS Parallel Benchmarks

    NASA Technical Reports Server (NTRS)

    Turney, Raymond D.; Thigpen, William W. (Technical Monitor)

    2001-01-01

    This report describes results of benchmark tests on Steger, a 250 MHz Origin 2000 system with R10K processors, currently installed at the NASA Ames National Advanced Supercomputing (NAS) facility. For comparison purposes, the tests were also run on Lomax, a 400 MHz Origin 2000 with R12K processors. The BT, LU, and SP application benchmarks in the NAS Parallel Benchmark Suite and the kernel benchmark FT were chosen to measure system performance. Having been written to measure performance on Computational Fluid Dynamics applications, these benchmarks are assumed appropriate to represent the NAS workload. Since the NAS runs both message passing (MPI) and shared-memory, compiler directive type codes, both MPI and OpenMP versions of the benchmarks were used. The MPI versions used were the latest official release of the NAS Parallel Benchmarks, version 2.3. The OpenMP versions used were PBN3b2, a beta version that is in the process of being released. NPB 2.3 and PBN3b2 are technically different benchmarks, and NPB results are not directly comparable to PBN results.

  9. First-principles study on structure stabilities of α-S and Na-S battery systems

    NASA Astrophysics Data System (ADS)

    Momida, Hiroyoshi; Oguchi, Tamio

    2014-03-01

    To understand microscopic mechanisms of charge and discharge reactions in Na-S batteries, there has been increasing needs to study fundamental atomic and electronic structures of elemental S as well as that of Na-S phases. The most stable form of S is known to be an orthorhombic α-S crystal at ambient temperature and pressure, and α-S consists of puckered S8 rings which crystallize in space group Fddd . In this study, the crystal structure of α-S is examined by using first-principles calculations with and without the van der Waals interaction corrections of Grimme's method, and results clearly show that the van der Waals interactions between the S8 rings have crucial roles on cohesion of α-S. We also study structure stabilities of Na2S, NaS, NaS2, and Na2S5 phases with reported crystal structures. Using calculated total energies of the crystal structure models, we estimate discharge voltages assuming discharge reactions from 2Na+ xS -->Na2Sx, and discharge reactions in Na/S battery systems are discussed by comparing with experimental results. This work was partially supported by Elements Strategy Initiative for Catalysts and Batteries (ESICB) of Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan.

  10. GaNAs as Strain Compensating Layer for 1.55 μm Light Emission from InAs Quantum Dots

    NASA Astrophysics Data System (ADS)

    Ganapathy, Sasikala; Zhang, Xi Qing; Suemune, Ikuo; Uesugi, Katsuhiro; Kumano, Hidekazu; Kim, B. J.; Seong, Tae-Yeon

    2003-09-01

    GaNAs strain-compensating layers (SCLs) are applied to bury InAs quantum dots (QDs) grown on GaAs substrates. The main idea is the compensation of the compressive strain induced by InAs QDs with the tensile strain in the GaNAs SCLs to keep the total strain of the system minimum. The application of the GaNAs SCLs resulted in a systematic shift of photoluminescence (PL) peaks of the InAs QDs toward the longer wavelengths with the increase of the nitrogen (N) composition in GaNAs, and luminescence at a wavelength of 1.55 μm has been achieved from the InAs QDs for the N composition of 2.7% in the GaNAs SCL. This result is promising for the application of GaNAs SCL for InAs-QDs-based long-wavelength light sources for optical-fiber communication systems.

  11. Bioterrorism awareness for EMS.

    PubMed

    Patrick, Richard W

    2004-04-01

    It is important to understand that the issues surrounding bioterrorism and all weapons of mass destruction are complex. In an effort to enhance response to such events, EMS should handle all incidents from the perspective of an all-hazards approach. Prevention, preparation, response and recovery are essential to the safe mitigation of all incidents. Organizations must be prepared. Plan now for a safer tomorrow. Your personnel and communities depend on you. PMID:15131906

  12. NasT-Mediated Antitermination Plays an Essential Role in the Regulation of the Assimilatory Nitrate Reductase Operon in Azotobacter vinelandii

    PubMed Central

    Pierson, Leland S.; Rensing, Christopher; Gunatilaka, Malkanthi K.; Kennedy, Christina

    2012-01-01

    Azotobacter vinelandii is a well-studied model system for nitrogen fixation in bacteria. Regulation of nitrogen fixation in A. vinelandii is independent of NtrB/NtrC, a conserved nitrogen regulatory system in proteobacteria. Previous work showed that an ntrC mutation in A. vinelandii resulted in a loss of induction of assimilatory nitrate and nitrite reductases encoded by the nasAB operon. In addition to NtrC, several other proteins, including NasT, a protein containing a potential RNA-binding domain ANTAR (AmiR and NasR transcription antitermination regulators), have been implicated in nasAB regulation. In this work, we characterize the sequence upstream of nasA and identify several DNA sequence elements, including two potential NtrC binding sites and a putative intrinsic transcriptional terminator upstream of nasA that are potentially involved in nasAB regulation. Our analyses confirm that the nasAB promoter, PnasA, is under NtrC control. However, unlike NtrC-regulated promoters in enteric bacteria, PnasA shows high activity in the presence of ammonium; in addition, the PnasA activity is altered in the nifA gene mutation background. We discuss the implication of these results on NtrC-mediated regulation in A. vinelandii. Our study provides direct evidence that induction of nasAB is regulated by NasT-mediated antitermination, which occurs within the leader region of the operon. The results also support the hypothesis that NasT binds the promoter proximal hairpin of nasAB for its regulatory function, which contributes to the understanding of the regulatory mechanism of ANTAR-containing antiterminators. PMID:22773651

  13. Efficient GaInNAs Gain Mirrors for Semiconductor Disk Lasers at 1.18 {mu}m and 1.22 {mu}m

    SciTech Connect

    Korpijaervi, Ville-Markus; Puustinen, Janne; Leinonen, Tomi; Rautiainen, Jussi; Haerkoenen, Antti; Hakkarainen, Teemu; Guina, Mircea

    2010-11-10

    We report two GaInNAs/GaAs semiconductor disk lasers emitting at the wavelengths of 1180 nm and 1220 nm. The lasers generated 5 W and 7 W output powers, respectively, at a mount temperature of 15 deg. C. Both the gain mirrors were grown by molecular beam epitaxy and consisted of a GaAs/AlAs distributed Bragg reflector and an active region with 10 GaInNAs/GaNAs/GaAs QWs.

  14. Benefits of a Unified LaSRS++ Simulation for NAS-Wide and High-Fidelity Modeling

    NASA Technical Reports Server (NTRS)

    Glaab, Patricia; Madden, Michael

    2014-01-01

    The LaSRS++ high-fidelity vehicle simulation was extended in 2012 to support a NAS-wide simulation mode. Since the initial proof-of-concept, the LaSRS++ NAS-wide simulation is maturing into a research-ready tool. A primary benefit of this new capability is the consolidation of the two modeling paradigms under a single framework to save cost, facilitate iterative concept testing between the two tools, and to promote communication and model sharing between user communities at Langley. Specific benefits of each type of modeling are discussed along with the expected benefits of the unified framework. Current capability details of the LaSRS++ NAS-wide simulations are provided, including the visualization tool, live data interface, trajectory generators, terminal routing for arrivals and departures, maneuvering, re-routing, navigation, winds, and turbulence. The plan for future development is also described.

  15. Determination of the nitrogen distribution in InGaNAs/GaAs quantum wells by transmission electron microscopy

    SciTech Connect

    Litvinov, D.; Gerthsen, D.; Rosenauer, A.; Hetterich, M.; Grau, A.; Gilet, Ph.; Grenouillet, L.

    2004-10-25

    We report on measurements of the nitrogen-concentration profile in an InGaNAs heterostructure by high-resolution transmission electron microscopy. Two samples grown by gas-source molecular-beam epitaxy on GaAs(001) substrates were investigated which contain InGaAs and InGaNAs wells with the same thickness and In concentration. The indium concentration was determined by high-resolution x-ray diffractometry. Indium-concentration profiles were obtained with the composition evaluation by lattice fringe analysis (CELFA) technique from the sample with the InGaAs wells exploiting the chemical sensitivity of the diffracted (002) beam. Nitrogen-concentration profiles were measured in the InGaNAs wells by comparison of the CELFA results observed in the samples with and without nitrogen.

  16. NAS Demand Predictions, Transportation Systems Analysis Model (TSAM) Compared with Other Forecasts

    NASA Technical Reports Server (NTRS)

    Viken, Jeff; Dollyhigh, Samuel; Smith, Jeremy; Trani, Antonio; Baik, Hojong; Hinze, Nicholas; Ashiabor, Senanu

    2006-01-01

    The current work incorporates the Transportation Systems Analysis Model (TSAM) to predict the future demand for airline travel. TSAM is a multi-mode, national model that predicts the demand for all long distance travel at a county level based upon population and demographics. The model conducts a mode choice analysis to compute the demand for commercial airline travel based upon the traveler s purpose of the trip, value of time, cost and time of the trip,. The county demand for airline travel is then aggregated (or distributed) to the airport level, and the enplanement demand at commercial airports is modeled. With the growth in flight demand, and utilizing current airline flight schedules, the Fratar algorithm is used to develop future flight schedules in the NAS. The projected flights can then be flown through air transportation simulators to quantify the ability of the NAS to meet future demand. A major strength of the TSAM analysis is that scenario planning can be conducted to quantify capacity requirements at individual airports, based upon different future scenarios. Different demographic scenarios can be analyzed to model the demand sensitivity to them. Also, it is fairly well know, but not well modeled at the airport level, that the demand for travel is highly dependent on the cost of travel, or the fare yield of the airline industry. The FAA projects the fare yield (in constant year dollars) to keep decreasing into the future. The magnitude and/or direction of these projections can be suspect in light of the general lack of airline profits and the large rises in airline fuel cost. Also, changes in travel time and convenience have an influence on the demand for air travel, especially for business travel. Future planners cannot easily conduct sensitivity studies of future demand with the FAA TAF data, nor with the Boeing or Airbus projections. In TSAM many factors can be parameterized and various demand sensitivities can be predicted for future travel. These

  17. Utilizing Traveler Demand Modeling to Predict Future Commercial Flight Schedules in the NAS

    NASA Technical Reports Server (NTRS)

    Viken, Jeff; Dollyhigh, Samuel; Smith, Jeremy; Trani, Antonio; Baik, Hojong; Hinze, Nicholas; Ashiabor, Senanu

    2006-01-01

    The current work incorporates the Transportation Systems Analysis Model (TSAM) to predict the future demand for airline travel. TSAM is a multi-mode, national model that predicts the demand for all long distance travel at a county level based upon population and demographics. The model conducts a mode choice analysis to compute the demand for commercial airline travel based upon the traveler s purpose of the trip, value of time, cost and time of the trip,. The county demand for airline travel is then aggregated (or distributed) to the airport level, and the enplanement demand at commercial airports is modeled. With the growth in flight demand, and utilizing current airline flight schedules, the Fratar algorithm is used to develop future flight schedules in the NAS. The projected flights can then be flown through air transportation simulators to quantify the ability of the NAS to meet future demand. A major strength of the TSAM analysis is that scenario planning can be conducted to quantify capacity requirements at individual airports, based upon different future scenarios. Different demographic scenarios can be analyzed to model the demand sensitivity to them. Also, it is fairly well know, but not well modeled at the airport level, that the demand for travel is highly dependent on the cost of travel, or the fare yield of the airline industry. The FAA projects the fare yield (in constant year dollars) to keep decreasing into the future. The magnitude and/or direction of these projections can be suspect in light of the general lack of airline profits and the large rises in airline fuel cost. Also, changes in travel time and convenience have an influence on the demand for air travel, especially for business travel. Future planners cannot easily conduct sensitivity studies of future demand with the FAA TAF data, nor with the Boeing or Airbus projections. In TSAM many factors can be parameterized and various demand sensitivities can be predicted for future travel. These

  18. Serious Gaming for Test & Evaluation of Clean-Slate (Ab Initio) National Airspace System (NAS) Designs

    NASA Technical Reports Server (NTRS)

    Allen, B. Danette; Alexandrov, Natalia

    2016-01-01

    Incremental approaches to air transportation system development inherit current architectural constraints, which, in turn, place hard bounds on system capacity, efficiency of performance, and complexity. To enable airspace operations of the future, a clean-slate (ab initio) airspace design(s) must be considered. This ab initio National Airspace System (NAS) must be capable of accommodating increased traffic density, a broader diversity of aircraft, and on-demand mobility. System and subsystem designs should scale to accommodate the inevitable demand for airspace services that include large numbers of autonomous Unmanned Aerial Vehicles and a paradigm shift in general aviation (e.g., personal air vehicles) in addition to more traditional aerial vehicles such as commercial jetliners and weather balloons. The complex and adaptive nature of ab initio designs for the future NAS requires new approaches to validation, adding a significant physical experimentation component to analytical and simulation tools. In addition to software modeling and simulation, the ability to exercise system solutions in a flight environment will be an essential aspect of validation. The NASA Langley Research Center (LaRC) Autonomy Incubator seeks to develop a flight simulation infrastructure for ab initio modeling and simulation that assumes no specific NAS architecture and models vehicle-to-vehicle behavior to examine interactions and emergent behaviors among hundreds of intelligent aerial agents exhibiting collaborative, cooperative, coordinative, selfish, and malicious behaviors. The air transportation system of the future will be a complex adaptive system (CAS) characterized by complex and sometimes unpredictable (or unpredicted) behaviors that result from temporal and spatial interactions among large numbers of participants. A CAS not only evolves with a changing environment and adapts to it, it is closely coupled to all systems that constitute the environment. Thus, the ecosystem that

  19. Improvement of InAs quantum-dot optical properties by strain compensation with GaNAs capping layers

    NASA Astrophysics Data System (ADS)

    Zhang, X. Q.; Ganapathy, S.; Suemune, I.; Kumano, H.; Uesugi, K.; Nabetani, Yoichi; Matsumoto, Takashi

    2003-12-01

    Two kinds of self-assembled InAs quantum dots (QDs) grown on GaAs (001) substrates were studied. One is capped with GaAs layers and the other with GaNAs strain-compensating layers. Photoluminescence (PL) measurements on the two kinds of InAs QDs showed distinct dependence on the selection of the capping layers. The homogeneity and luminescence efficiency of the InAs QDs were much improved when the net strain was reduced with GaNAs layers. These results demonstrate the importance of net strain compensation for the improved optical quality of InAs QDs.

  20. Observações simultâneas no óptico e infravermelho próximo dos BL Lacs PKS 2005-489 e PKS 2155-304 em diversas escalas de tempo

    NASA Astrophysics Data System (ADS)

    Dominici, T. P.; Abraham, Z.; Galo, A. L.

    2003-08-01

    A existência de variações rápidas de brilho em alguns blazares é um fenômeno bem comprovado, mas até agora não sabemos ao certo quais são os mecanismos físicos envolvidos. A maior dificuldade é a ausência de observações multibanda simultâneas que poderiam fornecer vínculos aos modelos. Buscando colaborar com a discussão estudamos o comportamento de dois BL Lacs, PKS 2005-489 e PKS 2155-304, em relação à variabilidade em diversas escalas de tempo, de poucos minutos até vários meses, com observações simultâneas em seis bandas espectrais (óptico e infravermelho próximo). Para tanto dois telescópios do LNA foram utilizados em conjunto nas campanhas observacionais realizadas em 2001 e 2002, cujos resultados são apresentados aqui. As duas fontes apresentaram características bastante diferentes, inclusive em relação à existência de variabilidade nos índices espectrais. Particularmente, registramos a primeira detecção de variações em escalas de tempo da ordem de poucos minutos em PKS 2005-489, com evidências da presença de um atraso entre as curvas de luz nas bandas V e R e a variação em R ocorrendo antes (o contrário do esperado no modelo de shock-in-jet). Em PKS 2155-304 detectamos pela primeira vez variabilidade em escalas de tempo de poucos minutos no infravermelho em um AGN. As observações indicam que as variações de brilho em blazares são o resultado da ação de mais de um fenômeno, especialmente em escalas de tempo muito curtas. Alguns cenários físicos são sugeridos para explicar os resultados observacionais.

  1. Temperature coefficients for GaInP/GaAs/GaInNAsSb solar cells

    SciTech Connect

    Aho, Arto; Isoaho, Riku; Tukiainen, Antti; Polojärvi, Ville; Aho, Timo; Raappana, Marianna; Guina, Mircea

    2015-09-28

    We report the temperature coefficients for MBE-grown GaInP/GaAs/GaInNAsSb multijunction solar cells and the corresponding single junction sub-cells. Temperature-dependent current-voltage measurements were carried out using a solar simulator equipped with a 1000 W Xenon lamp and a three-band AM1.5D simulator. The triple-junction cell exhibited an efficiency of 31% at AM1.5G illumination and an efficiency of 37–39% at 70x real sun concentration. The external quantum efficiency was also measured at different temperatures. The temperature coefficients up to 80°C, for the open circuit voltage, the short circuit current density, and the conversion efficiency were determined to be −7.5 mV/°C, 0.040 mA/cm{sup 2}/°C, and −0.09%/°C, respectively.

  2. Characterization of a Dominant Electron Trap in GaNAs Using Deep-Level Spectroscopy

    SciTech Connect

    Johnston, S. W.; Kurtz, S. R.

    2006-08-01

    Dilute-nitrogen GaNAs epitaxial layers grown by metal-organic chemical vapor deposition were characterized by deep-level transient spectroscopy (DLTS). For all samples, the dominant DLTS signal corresponds to an electron trap having an activation energy of about 0.25 to 0.35 eV. The minority-carrier trap density in the p-type material is quantified based on computer simulation of the devices. The simulations show that only about 2% of the traps in the depleted layer are filled during the transient. The fraction of the traps that are filled depends strongly on the depth of the trap, but only weakly on the doping of the layers and on the conduction-band offset. The simulations provide a pathway to obtain semi-quantitative data for analysis of minority-carrier traps by DLTS.

  3. 615 nm GaInNAs VECSEL with output power above 10 W.

    PubMed

    Kantola, Emmi; Leinonen, Tomi; Penttinen, Jussi-Pekka; Korpijärvi, Ville-Markus; Guina, Mircea

    2015-08-10

    A high-power optically-pumped vertical-external-cavity surface-emitting laser (VECSEL) generating 10.5 W of cw output power at 615 nm is reported. The gain mirror incorporated 10 GaInNAs quantum wells and was designed to have an emission peak in the 1230 nm range. The fundamental emission was frequency doubled to the red spectral range by using an intra-cavity nonlinear LBO crystal. The maximum optical-to-optical conversion efficiency was 17.5%. The VECSEL was also operated in pulsed mode by directly modulating the pump laser to produce light pulses with duration of ~1.5 µs. The maximum peak power for pulsed operation (pump limited) was 13.8 W. This corresponded to an optical-to-optical conversion efficiency of 20.4%. PMID:26367883

  4. >8W GaInNAs VECSEL emitting at 615 nm

    NASA Astrophysics Data System (ADS)

    Leinonen, Tomi; Penttinen, Jussi-Pekka; Korpijärvi, Ville-Markus; Kantola, Emmi; Guina, Mircea

    2015-03-01

    We report a high-power VECSEL emitting <8W around 615 nm. The gain chip of the laser was grown by plasmaassisted molecular beam epitaxy and it comprised 10 GaInNAs quantum wells. The VECSEL cavity had a V-shaped geometry and a 10-mm-long non-critically phase-matched LBO crystal for second harmonic generation. The cavity incorporated also an etalon and a birefringent filter for controlling the output wavelength. With the aid of the secondharmonic output and the infrared light leaking out from the laser cavity, the single-pass conversion efficiency of the crystal was estimated to have a value of 0.75%.

  5. Security Risk Assessment Process for UAS in the NAS CNPC Architecture

    NASA Technical Reports Server (NTRS)

    Iannicca, Dennis Christopher; Young, Daniel Paul; Suresh, Thadhani; Winter, Gilbert A.

    2013-01-01

    This informational paper discusses the risk assessment process conducted to analyze Control and Non-Payload Communications (CNPC) architectures for integrating civil Unmanned Aircraft Systems (UAS) into the National Airspace System (NAS). The assessment employs the National Institute of Standards and Technology (NIST) Risk Management framework to identify threats, vulnerabilities, and risks to these architectures and recommends corresponding mitigating security controls. This process builds upon earlier work performed by RTCA Special Committee (SC) 203 and the Federal Aviation Administration (FAA) to roadmap the risk assessment methodology and to identify categories of information security risks that pose a significant impact to aeronautical communications systems. A description of the deviations from the typical process is described in regards to this aeronautical communications system. Due to the sensitive nature of the information, data resulting from the risk assessment pertaining to threats, vulnerabilities, and risks is beyond the scope of this paper

  6. Security Risk Assessment Process for UAS in the NAS CNPC Architecture

    NASA Technical Reports Server (NTRS)

    Iannicca, Dennis C.; Young, Dennis P.; Thadani, Suresh K.; Winter, Gilbert A.

    2013-01-01

    This informational paper discusses the risk assessment process conducted to analyze Control and Non-Payload Communications (CNPC) architectures for integrating civil Unmanned Aircraft Systems (UAS) into the National Airspace System (NAS). The assessment employs the National Institute of Standards and Technology (NIST) Risk Management framework to identify threats, vulnerabilities, and risks to these architectures and recommends corresponding mitigating security controls. This process builds upon earlier work performed by RTCA Special Committee (SC) 203 and the Federal Aviation Administration (FAA) to roadmap the risk assessment methodology and to identify categories of information security risks that pose a significant impact to aeronautical communications systems. A description of the deviations from the typical process is described in regards to this aeronautical communications system. Due to the sensitive nature of the information, data resulting from the risk assessment pertaining to threats, vulnerabilities, and risks is beyond the scope of this paper.

  7. The conjugate gradient NAS parallel benchmark on the IBM SP1

    SciTech Connect

    Trefethen, A.E.; Zhang, T.

    1994-12-31

    The NAS Parallel Benchmarks are a suite of eight benchmark problems developed at the NASA Ames Research Center. They are specified in such a way that the benchmarkers are free to choose the language and method of implementation to suit the system in which they are interested. In this presentation the authors will discuss the Conjugate Gradient benchmark and its implementation on the IBM SP1. The SP1 is a parallel system which is comprised of RS/6000 nodes connected by a high performance switch. They will compare the results of the SP1 implementation with those reported for other machines. At this time, such a comparison shows the SP1 to be very competitive.

  8. Temperature coefficients for GaInP/GaAs/GaInNAsSb solar cells

    NASA Astrophysics Data System (ADS)

    Aho, Arto; Isoaho, Riku; Tukiainen, Antti; Polojärvi, Ville; Aho, Timo; Raappana, Marianna; Guina, Mircea

    2015-09-01

    We report the temperature coefficients for MBE-grown GaInP/GaAs/GaInNAsSb multijunction solar cells and the corresponding single junction sub-cells. Temperature-dependent current-voltage measurements were carried out using a solar simulator equipped with a 1000 W Xenon lamp and a three-band AM1.5D simulator. The triple-junction cell exhibited an efficiency of 31% at AM1.5G illumination and an efficiency of 37-39% at 70x real sun concentration. The external quantum efficiency was also measured at different temperatures. The temperature coefficients up to 80°C, for the open circuit voltage, the short circuit current density, and the conversion efficiency were determined to be -7.5 mV/°C, 0.040 mA/cm2/°C, and -0.09%/°C, respectively.

  9. Development of computer program NAS3D using Vector processing for geometric nonlinear analysis of structures

    NASA Technical Reports Server (NTRS)

    Mangalgiri, P. D.; Prabhakaran, R.

    1986-01-01

    An algorithm for vectorized computation of stiffness matrices of an 8 noded isoparametric hexahedron element for geometric nonlinear analysis was developed. This was used in conjunction with the earlier 2-D program GAMNAS to develop the new program NAS3D for geometric nonlinear analysis. A conventional, modified Newton-Raphson process is used for the nonlinear analysis. New schemes for the computation of stiffness and strain energy release rates is presented. The organization the program is explained and some results on four sample problems are given. The study of CPU times showed that savings by a factor of 11 to 13 were achieved when vectorized computation was used for the stiffness instead of the conventional scalar one. Finally, the scheme of inputting data is explained.

  10. Seismic reflection exploration of geothermal reservoir at Naval Air Station (NAS) Fallon, Nevada

    NASA Astrophysics Data System (ADS)

    Alay G., Gebregiorgis

    The Primary objective of this study is to increase geologic and tectonic understanding of the geothermal resources at the Naval Air Station (NAS) Fallon, Nevada. The seismic reflection method is employed to study faults, fractures and other tectonic structures in the subsurface in order to identify geothermal drill targets. The efficiency of geothermal systems is strongly dependent on water circulation. Discrete faults may be permeable and provide pathways for water flow depending on the fracture density. It is therefore desirable to detect and map faults and fracture zones and characterize their physical properties when evaluating a geothermal prospect. The seismic data for this project were provided by the NAS environmental research program in Ridgecrest, CA. However, the data collection information was not available so the work includes determining the line geometry and mapping shot points to field files in order to process the data. ProMAX 2D(TM) is the software used to determine the geometry and to process the data. Data processing includes eliminating noise, datum and refraction statics, trace muting, bandpass filter, automatic gain control, amplitude recovery, CMP sorting, velocity analysis and NMO correction, stacking and migration. The results of this study indicate the presence of thick basin fill including Tertiary and Quaternary sediments underlain by Tertiary basalts which are interpreted to be capping rocks for the geothermal reservoirs. This seismic reflection study also reveals the presence of strongly fractured pre-Tertiary basement complex with their top at about 1500m on the north and west and about 900 m on the eastern and southern part of the study area.

  11. Origin and annealing of deep-level defects in GaNAs grown by metalorganic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Gelczuk, Ł.; Stokowski, H.; Dąbrowska-Szata, M.; Kudrawiec, R.

    2016-05-01

    Deep-level defects were investigated by deep level transient spectroscopy on the as-grown and annealed GaNAs layers of various nitrogen (N) contents. The unintentionally doped (uid) GaNAs layers were grown by metalorganic vapor phase epitaxy with N = 1.4%, 2.0%, 2.2%, and 2.4% on GaAs substrate. The possible origin and evolution of the deep-level defects upon annealing were analyzed with the use of the GaNAs band gap diagram concept [Kudrawiec et al., Appl. Phys. Lett. 101, 082109 (2012)], which assumes that the activation energy of donor traps decreases with N-related downward shift of the conduction band. On the basis of this diagram and in comparison with previous results, the N-related traps were associated with (N-As)As or (N-N)As split interstitials. It was also proposed that one of the electron traps and the hole trap, lying at the same level position in the bandgap of the annealed uid-GaNAs layers, can both act as one generation-recombination center partially responsible for poor optical properties of this alloy.

  12. 78 FR 21084 - Proposed Amendment of Class D and E Airspace, and Establishment of Class E Airspace; Oceana NAS, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-09

    ... Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of... Traffic Control Tower at Oceana NAS (Apollo Soucek Field) operating on a part time basis. This action...-0038; Airspace Docket No. 13-AEA-2, at the beginning of your comments. You may also submit and...

  13. 78 FR 46497 - Amendment of Class D and E Airspace, and Establishment of Class E Airspace; Oceana NAS, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-01

    ... airspace, and establish Class E airspace at Oceana Naval Air Station, (NAS), VA, (78 FR 21084). Interested... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does..., 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The...

  14. Right and Wrong and Cultural Diversity: Replication of the 2002 NAS/Zogby Poll on Business Ethics

    ERIC Educational Resources Information Center

    Ludlum, Marty; Mascaloinov, Sergei

    2004-01-01

    In April 2002, a NAS/Zogby poll found that only a quarter of sampled students perceived uniform standards of "right and wrong" and that most students felt that ethical behavior depends on cultural diversity. In this effort to replicate those findings in a larger sample of American college students, the authors obtained results that contradict the…

  15. EPA'S REANALYSIS OF KEY ISSUES RELATED TO DIOXIN TOXICITY AND RESPONSE TO NAS COMMENTS (VOLUME 1) (INTERAGENCY SCIENCE DISCUSSION DRAFT)

    EPA Science Inventory

    EPA is releasing the draft report, EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments (Volume 1), that was distributed to Federal agencies and White House Offices for comment during the Science Discussion step of the One-dimensional carbon-sulfur composite fibers for Na-S rechargeable batteries operating at room temperature.

    PubMed

    Hwang, Tae Hoon; Jung, Dae Soo; Kim, Joo-Seong; Kim, Byung Gon; Choi, Jang Wook

    2013-09-11

    Na-S batteries are one type of molten salt battery and have been used to support stationary energy storage systems for several decades. Despite their successful applications based on long cycle lives and low cost of raw materials, Na-S cells require high temperatures above 300 °C for their operations, limiting their propagation into a wide range of applications. Herein, we demonstrate that Na-S cells with solid state active materials can perform well even at room temperature when sulfur-containing carbon composites generated from a simple thermal reaction were used as sulfur positive electrodes. Furthermore, this structure turned out to be robust during repeated (de)sodiation for ~500 cycles and enabled extraordinarily high rate performance when one-dimensional morphology is adopted using scalable electrospinning processes. The current study suggests that solid-state Na-S cells with appropriate atomic configurations of sulfur active materials could cover diverse battery applications where cost of raw materials is critical. PMID:23981085

  16. Strongly polarized quantum-dot-like light emitters embedded in GaAs/GaNAs core/shell nanowires.

    PubMed

    Filippov, S; Jansson, M; Stehr, J E; Palisaitis, J; Persson, P O Å; Ishikawa, F; Chen, W M; Buyanova, I A

    2016-09-21

    Recent developments in fabrication techniques and extensive investigations of the physical properties of III-V semiconductor nanowires (NWs), such as GaAs NWs, have demonstrated their potential for a multitude of advanced electronic and photonics applications. Alloying of GaAs with nitrogen can further enhance the performance and extend the device functionality via intentional defects and heterostructure engineering in GaNAs and GaAs/GaNAs coaxial NWs. In this work, it is shown that incorporation of nitrogen in GaAs NWs leads to formation of three-dimensional confining potentials caused by short-range fluctuations in the nitrogen composition, which are superimposed on long-range alloy disorder. The resulting localized states exhibit a quantum-dot like electronic structure, forming optically active states in the GaNAs shell. By directly correlating the structural and optical properties of individual NWs, it is also shown that formation of the localized states is efficient in pure zinc-blende wires and is further facilitated by structural polymorphism. The light emission from these localized states is found to be spectrally narrow (∼50-130 μeV) and is highly polarized (up to 100%) with the preferable polarization direction orthogonal to the NW axis, suggesting a preferential orientation of the localization potential. These properties of self-assembled nano-emitters embedded in the GaNAs-based nanowire structures may be attractive for potential optoelectronic applications. PMID:27537077

  17. National Academy of Sciences (NAS) Study entitled The Effect of Climate Change on Indoor Air Quality and Public Health.

    EPA Science Inventory

    The Institute of Medicine of the NAS is conducting a study to evaluate the state of scientific understanding of the effects of climate change on indoor air quality and public health. General topics may include the likely impacts of climate change in the U.S. on the indoor environ...

  18. Room temperature continuous-wave operation of GaInNAs long wavelength VCSELs

    SciTech Connect

    Larson, M C; Coldren, C W; Spruytte, S G; Peterson, H E; Harris, J S

    2000-06-22

    Vertical cavity surface-emitting lasers (VCSELs) are becoming increasingly important for short-haul optical fiber transmission systems. Given the commercial success of GaAs-based 850nm VCSELs, dramatic enhancements in transmission bandwidth and distance can be achieved in conventional single- and multi-mode fiber by extending the emission wavelength to the 1300nm-1550nm range. GaInNAs is a promising active layer material grown on GaAs that can achieve 1300nm emission [l], and electrically pulsed broad-area GaInNAs VCSELs [2,3] have been realized. Here we take advantage of the properties of GaAs-based materials-thermally-conductive high contrast mirrors and AlAs-oxide current apertures-to demonstrate for the first time low-threshold ({approx}1 mA) GaInNAs VCSELs emitting at a wavelength of 1200 nm under continuous-wave room temperature operation. The device structure is shown schematically in figure 1. The bottom mirror consists of a 22.5-period n-doped GaAs/AlAs distributed Bragg reflector (DBR) designed for a center wavelength {lambda} near 1200nm, the top mirror is a 22-period p-doped DBR whose reflectance is enhanced by a Ti/Au contact electrode, and the GaAs {lambda} cavity contains three 70{angstrom}, Ga{sub 0.3}In{sub 0.7}N{sub 0.02}As{sub 0.98} quantum wells (QWs) separated by 200{angstrom} GaAs barriers. The epilayers were grown by molecular beam epitaxy using solid-source arsenic and a rf nitrogen plasma source. After growth, the first 17 mirror periods of the top mirror were dry etched and subsequently capped with SiO{sub 2}, and the remaining three periods were etched to expose the AlAs for lateral oxidation, which formed square unoxidized apertures as small as 3.6 {micro}m on a side. After the top contact metalization, devices were mounted without heat sinking on a glass slide for optical emission through the substrate, which was contacted electrically with indium solder. The output power and voltage vs. injection current for a 5{micro}m x 5{micro

  19. Laser Gain and Threshold Properties in Compressive-Strained and Lattice-Matched GaInNAs/GaAs Quantum Wells

    SciTech Connect

    Chow, W.W.; Jones, E.D.; Modine, N.A.; Allerman, A.A.; Kurtz, S.R.

    1999-08-04

    The optical gain spectra for compressive-strained and lattice-matched GaInNAs/GaAs quantum wells are computed using a microscopic laser theory. From these spectra, the peak gain and carrier radiative decay rate as functions of carrier density are determined. These dependences allow the study of lasing threshold current density for different GAInNAs/GaAs laser structures.

  1. Identified EM Earthquake Precursors

    NASA Astrophysics Data System (ADS)

    Jones, Kenneth, II; Saxton, Patrick

    2014-05-01

    Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After a number of custom rock experiments, two hypotheses were formed which could answer the EM wave model. The first hypothesis concerned a sufficient and continuous electron movement either by surface or penetrative flow, and the second regarded a novel approach to radio transmission. Electron flow along fracture surfaces was determined to be inadequate in creating strong EM fields, because rock has a very high electrical resistance making it a high quality insulator. Penetrative flow could not be corroborated as well, because it was discovered that rock was absorbing and confining electrons to a very thin skin depth. Radio wave transmission and detection worked with every single test administered. This hypothesis was reviewed for propagating, long-wave generation with sufficient amplitude, and the capability of penetrating solid rock. Additionally, fracture spaces, either air or ion-filled, can facilitate this concept from great depths and allow for surficial detection. A few propagating precursor signals have been detected in the field occurring with associated phases using custom-built loop antennae. Field testing was conducted in Southern California from 2006-2011, and outside the NE Texas town of Timpson in February, 2013. The antennae have mobility and observations were noted for

  2. Direct visualization of the N impurity state in dilute GaNAs using scanning tunneling microscopy

    NASA Astrophysics Data System (ADS)

    Ishida, Nobuyuki; Jo, Masafumi; Mano, Takaaki; Sakuma, Yoshiki; Noda, Takeshi; Fujita, Daisuke

    2015-10-01

    The interaction between nitrogen (N) impurity states in III-V compounds plays a key role in controlling optoelectronic properties of the host materials. Here, we use scanning tunneling microscopy to characterize the spatial distribution and electronic properties of N impurity states in dilute GaNAs. We demonstrated that the N impurity states can be directly visualized by taking empty state current images using the multipass scanning method. The N impurity states broadened over several nanometers and exhibited a highly anisotropic distribution with a bowtie-like shape on the GaAs(110) surface, which can be explained by anisotropic propagation of strain along the zigzag chains of Ga and As atoms in the {110} plane. Our experimental findings provide strong insights into a possible role of N impurity states in modifying properties of the host materials.The interaction between nitrogen (N) impurity states in III-V compounds plays a key role in controlling optoelectronic properties of the host materials. Here, we use scanning tunneling microscopy to characterize the spatial distribution and electronic properties of N impurity states in dilute GaNAs. We demonstrated that the N impurity states can be directly visualized by taking empty state current images using the multipass scanning method. The N impurity states broadened over several nanometers and exhibited a highly anisotropic distribution with a bowtie-like shape on the GaAs(110) surface, which can be explained by anisotropic propagation of strain along the zigzag chains of Ga and As atoms in the {110} plane. Our experimental findings provide strong insights into a possible role of N impurity states in modifying properties of the host materials. Electronic supplementary information (ESI) available: Identification of N impurity positions in terms of depth of depressions in the filled state topographic image. Filled state topographic images of N impurity in the fourth plane. Slight modification of topographic height

  3. Photoluminescence study of Be acceptors in GaInNAs epilayers

    NASA Astrophysics Data System (ADS)

    Tsai, Y.; Barman, B.; Scrace, T.; Petrou, A.; Fukuda, M.; Sellers, I. R.; Leroux, M.; Khalfioui, M. A.

    2014-03-01

    We have studied the photoluminescence (PL) spectra from MBE grown GaInNAs epilayers doped p-type with Beryllium acceptors. The measurements were carried out in the 5 K - 70 K temperature range and in magnetic fields (B) up to 7 tesla. The PL spectra contain two features at T = 5 K: The exciton at 1093 meV and a second broader feature at 1058 meV. The intensity of this feature decreases with increasing temperature and disappears completely by 70K while the excitonic feature persists. The emission at 1058meV is identified as the conduction band to Beryllium acceptor transition. If we take into account the binding energy of the exciton [3] we get a value of 23 meV for the Beryllium acceptor binding energy. The acceptor related transition was studied as a function of magnetic field; the energy of this transition has a linear dependence on B with a slope of 055 meV/T. Research supported by Amethyst Research In. through the State of Oklahoma, ONAP program.

  4. Air Traffic Controller Performance and Acceptability of Multiple UAS in a Simulated NAS Environment

    NASA Technical Reports Server (NTRS)

    Vu, Kim-Phuong L.; Strybel, Thomas; Chiappe, Dan; Morales, Greg; Battiste, Vernol; Shively, Robert Jay

    2014-01-01

    Previously, we showed that air traffic controllers (ATCos) rated UAS pilot verbal response latencies as acceptable when a 1.5 s delay was added to the UAS pilot responses, but a 5 s delay was rated as mostly unacceptable. In the present study we determined whether a 1.5 s added delay in the UAS pilots' verbal communications would affect ATCos interactions with UAS and other conventional aircraft when the number and speed of the UAS were manipulated. Eight radar-certified ATCos participated in this simulation. The ATCos managed a medium altitude sector containing arrival aircraft, en route aircraft, and one to four UAS. The UAS were conducting a surveillance mission and flew at either a "slow" or "fast" speed. We measured both UAS and conventional pilots' verbal communication latencies, and obtained ATCos' acceptability ratings for these latencies. Although the UAS pilot response latencies were longer than those of conventional pilots, the ATCos rated UAS pilot verbal communication latencies to be as acceptable as those of conventional pilots. Because the overall traffic load within the sector was held constant, ATCos only performed slightly worse when multiple UAS were in their sector compared to when only one UAS was in the sector. Implications of these findings for UAS integration in the NAS are discussed.

  5. MPI, HPF or OpenMP: A Study with the NAS Benchmarks

    NASA Technical Reports Server (NTRS)

    Jin, Hao-Qiang; Frumkin, Michael; Hribar, Michelle; Waheed, Abdul; Yan, Jerry; Saini, Subhash (Technical Monitor)

    1999-01-01

    Porting applications to new high performance parallel and distributed platforms is a challenging task. Writing parallel code by hand is time consuming and costly, but the task can be simplified by high level languages and would even better be automated by parallelizing tools and compilers. The definition of HPF (High Performance Fortran, based on data parallel model) and OpenMP (based on shared memory parallel model) standards has offered great opportunity in this respect. Both provide simple and clear interfaces to language like FORTRAN and simplify many tedious tasks encountered in writing message passing programs. In our study we implemented the parallel versions of the NAS Benchmarks with HPF and OpenMP directives. Comparison of their performance with the MPI implementation and pros and cons of different approaches will be discussed along with experience of using computer-aided tools to help parallelize these benchmarks. Based on the study,potentials of applying some of the techniques to realistic aerospace applications will be presented

  6. Photoluminescence of InNAs alloys: S-shaped temperature dependence and conduction-band nonparabolicity

    NASA Astrophysics Data System (ADS)

    Merrick, M.; Cripps, S. A.; Murdin, B. N.; Hosea, T. J. C.; Veal, T. D.; McConville, C. F.; Hopkinson, M.

    2007-08-01

    Photoluminescence (PL) has been used as a means of unambiguously observing band gap reduction in InNAs epilayers grown by molecular beam epitaxy. The observed redshift in room temperature emission as a function of nitrogen concentration is in agreement with the predictions of the band anticrossing (BAC) model, as implemented with model parameters derived from tight-binding calculations. The temperature dependence of the emission from certain samples exhibits a signature non-Varshni-like behavior indicative of electron trapping in nitrogen-related localized states below the conduction-band edge, as predicted by the linear combination of isolated nitrogen states (LCINS) model. This non-Varshni-like behavior tends to grow more pronounced with increasing nitrogen content, but for the highest nitrogen concentration studied, the more familiar Varshni-like behavior is recovered. Although unexpected, this observation is found to be consistent with the BAC and LCINS models. With consideration given to the effects of conduction-band nonparabolicity on the emission line shapes, the BAC model parameters extracted from the measured PL transition energies are found to be in excellent agreement with the predictions of the aforementioned tight-binding calculations.

  7. MPI, HPF or OpenMP: A Study with the NAS Benchmarks

    NASA Technical Reports Server (NTRS)

    Jin, H.; Frumkin, M.; Hribar, M.; Waheed, A.; Yan, J.; Saini, Subhash (Technical Monitor)

    1999-01-01

    Porting applications to new high performance parallel and distributed platforms is a challenging task. Writing parallel code by hand is time consuming and costly, but this task can be simplified by high level languages and would even better be automated by parallelizing tools and compilers. The definition of HPF (High Performance Fortran, based on data parallel model) and OpenMP (based on shared memory parallel model) standards has offered great opportunity in this respect. Both provide simple and clear interfaces to language like FORTRAN and simplify many tedious tasks encountered in writing message passing programs. In our study, we implemented the parallel versions of the NAS Benchmarks with HPF and OpenMP directives. Comparison of their performance with the MPI implementation and pros and cons of different approaches will be discussed along with experience of using computer-aided tools to help parallelize these benchmarks. Based on the study, potentials of applying some of the techniques to realistic aerospace applications will be presented.

  8. UAS Integration into the NAS: Unmanned Aircraft System (UAS) Delegation of Separation

    NASA Technical Reports Server (NTRS)

    Fern, Lisa Carolynn; Kenny, Caitlin Ailis

    2012-01-01

    FAA Modernization and Reform Act of 2012 mandates UAS integration in the NAS by 2015. Operators must be able to safely maneuver UAS to maintain separation and collision avoidance. Delegated Separation is defined as the transfer of responsibility for maintaining separation between aircraft or vehicles from the air navigation service provider to the relevant flight operator, and will likely begin in sparsely trafficked areas before moving to more heavily populated airspace. As UAS operate primarily in areas with lower traffic density and perform maneuvers routinely that are currently managed through special handling, they have the advantage of becoming an early adopter of delegated separation. This experiment will examine if UAS are capable of performing delegated separation in 5 nm horizontal and 1000 ft vertical distances under two delegation conditions. In Extended Delegation, ATC are in charge of identifying problems and delegating to pilot identification and implementation of the solution and monitoring. In Full Delegation, the pilots are responsible for all tasks related to separation assurance: identification of problems and solutions, implementation and monitoring.

  9. 1-eV GaInNAs solar cells for ultrahigh-frequency multijunction devices

    SciTech Connect

    Friedman, D.J.; Geisz, J.F.; Kurtz, S.R.; Olson, J.M.

    1998-09-01

    The authors demonstrate working prototypes of a GaInNAs-based solar cell lattice-matched to GaAs with photoresponse down to 1 eV. This device is intended for use as the third junction of future-generation ultrahigh-efficiency three- and four-junction devices. Under the AM1.5 direct spectrum with all the light higher in energy than the GaAs band gap filtered out, the prototypes have open-circuit voltages ranging from 0.35 to 0.44 V, short-circuit currents of 1.8 mA/cm{sup 2}, and fill factors from 61--66%. The short-circuit currents are of principal concern: the internal quantum efficiencies rise only to about 0.2. The authors discuss the short diffusion lengths which are the reason for this low photocurrent. As a partial workaround for the poor diffusion lengths, they demonstrate a depletion-width-enhanced variation of one of the prototype devices that grades off decreased voltage for increased photocurrent, with a short-circuit current of 6.5 mA/cm{sup 2} and an open-circuit voltage of 0.29 V.

  10. EPA LABORATORIES IMPLEMENT EMS PROGRAM

    EPA Science Inventory

    This paper highlights the breadth and magnitude of carrying out an effective Environmental Management System (EMS) program at the U.S. EPA's research and development laboratories. Federal research laboratories have unique operating challenges compared to more centralized industr...

  11. The structure of the NasR transcription antiterminator reveals a one-component system with a NIT nitrate receptor coupled to an ANTAR RNA-binding effector.

    PubMed

    Boudes, Marion; Lazar, Noureddine; Graille, Marc; Durand, Dominique; Gaidenko, Tatiana A; Stewart, Valley; van Tilbeurgh, Herman

    2012-08-01

    The nitrate- and nitrite-sensing NIT domain is present in diverse signal-transduction proteins across a wide range of bacterial species. NIT domain function was established through analysis of the Klebsiella oxytoca NasR protein, which controls expression of the nasF operon encoding enzymes for nitrite and nitrate assimilation. In the presence of nitrate or nitrite, the NasR protein inhibits transcription termination at the factor-independent terminator site in the nasF operon transcribed leader region. We present here the crystal structure of the intact NasR protein in the apo state. The dimeric all-helical protein contains a large amino-terminal NIT domain that associates two four-helix bundles, and a carboxyl-terminal ANTAR (AmiR and NasR transcription antitermination regulator) domain. The analysis reveals unexpectedly that the NIT domain is structurally similar to the periplasmic input domain of the NarX two-component sensor that regulates nitrate and nitrite respiration. This similarity suggests that the NIT domain binds nitrate and nitrite between two invariant arginyl residues located on adjacent alpha helices, and results from site-specific mutagenesis showed that these residues are critical for NasR function. The resulting structural movements in the NIT domain would provoke an active configuration of the ANTAR domains necessary for specific leader mRNA binding. PMID:22690729

  12. Photoconductivity and photoluminescence under bias in GaInNAs/GaAs MQW p-i-n structures.

    PubMed

    Khalil, Hagir M; Royall, Ben; Mazzucato, Simone; Balkan, Naci

    2012-01-01

    The low temperature photoluminescence under bias (PLb) and the photoconductivity (PC) of a p-i-n GaInNAs/GaAs multiple quantum well sample have been investigated. Under optical excitation with photons of energy greater than the GaAs bandgap, PC and PLb results show a number of step-like increases when the sample is reverse biased. The nature of these steps, which depends upon the temperature, exciting wavelength and intensity and the number of quantum wells (QWs) in the device, is explained in terms of thermionic emission and negative charge accumulation due to the low confinement of holes in GaInNAs QWs. At high temperature, thermal escape from the wells becomes much more dominant and the steps smear out. PMID:23021540

  13. Photoconductivity and photoluminescence under bias in GaInNAs/GaAs MQW p-i-n structures

    PubMed Central

    2012-01-01

    The low temperature photoluminescence under bias (PLb) and the photoconductivity (PC) of a p-i-n GaInNAs/GaAs multiple quantum well sample have been investigated. Under optical excitation with photons of energy greater than the GaAs bandgap, PC and PLb results show a number of step-like increases when the sample is reverse biased. The nature of these steps, which depends upon the temperature, exciting wavelength and intensity and the number of quantum wells (QWs) in the device, is explained in terms of thermionic emission and negative charge accumulation due to the low confinement of holes in GaInNAs QWs. At high temperature, thermal escape from the wells becomes much more dominant and the steps smear out. PMID:23021540

  14. Nitrate and nitrite-mediated transcription antitermination control of nasF (nitrate assimilation) operon expression in Klebsiella pheumoniae M5al.

    PubMed

    Lin, J T; Stewart, V

    1996-03-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources during aerobic growth. Nitrate is converted through nitrite to ammonium by assimilatory nitrate and nitrite reductase, respectively. Enzymes required for nitrate assimilation are encoded by the nasFEDCBA operon of K. pneumoniae; nasF operon expression is subject to both general nitrogen control and pathway-specific nitrate/nitrite induction, mediated by the NtrC and NasR proteins, respectively. Sequence inspection revealed a presumptive sigmaN (sigma54)-dependent promoter as well as two presumptive upstream NtrC protein binding sites. Site-specific mutational and primer extension analyses confirmed the identity of the sigmaN-dependent promoter. Deletions removing the apparent NtrC protein binding sites greatly reduced NtrC-dependent regulation, indicating that these sites are involved in general nitrogen control. However, deletions removing most of the sequence upstream of the promoter had little effect on nitrate/nitrite regulation, suggesting that the nasF leader region is involved in nitrate/nitrite regulation. The 119 nucleotide long transcribed leader region contains an apparent factor-independent transcription terminator. Promoter replacement experiments demonstrated that the leader region is involved in nitrate/nitrite regulation of nasF operon expression. Deletions removing the transcription terminator structure resulted in a nitrate-blind constitutive phenotype, indicating that the transcription terminator structure serves a negative function. Other deletions, removing proximal portions of the leader region, resulted in an uninducible phenotype, indicating that this region serves a positive function. These results indicate that nitrate/nitrite regulation of nasF operon expression is determined by a transcription attenuation mechanism. We hypothesize that in the absence of nitrate or nitrite, the terminator structure abrogates transcription readthrough into the nasF operon. In the

  15. NASA's UAS Integration into the NAS: A Report on the Human Systems Integration Phase 1 Simulation Activities

    NASA Technical Reports Server (NTRS)

    Fern, Lisa; Rorie, R. Conrad; Shively, R. Jay

    2014-01-01

    In 2011 the National Aeronautics and Space Administration (NASA) began a five-year Project to address the technical barriers related to routine access of Unmanned Aerial Systems (UAS) in the National Airspace System (NAS). Planned in two phases, the goal of the first phase was to lay the foundations for the Project by identifying those barriers and key issues to be addressed to achieve integration. Phase 1 activities were completed two years into the five-year Project. The purpose of this paper is to review activities within the Human Systems Integration (HSI) subproject in Phase 1 toward its two objectives: 1) develop GCS guidelines for routine UAS access to the NAS, and 2) develop a prototype display suite within an existing Ground Control Station (GCS). The first objective directly addresses a critical barrier for UAS integration into the NAS - a lack of GCS design standards or requirements. First, the paper describes the initial development of a prototype GCS display suite and supporting simulation software capabilities. Then, three simulation experiments utilizing this simulation architecture are summarized. The first experiment sought to determine a baseline performance of UAS pilots operating in civil airspace under current instrument flight rules for manned aircraft. The second experiment examined the effect of currently employed UAS contingency procedures on Air Traffic Control (ATC) participants. The third experiment compared three GCS command and control interfaces on UAS pilot response times in compliance with ATC clearances. The authors discuss how the results of these and future simulation and flight-testing activities contribute to the development of GCS guidelines to support the safe integration of UAS into the NAS. Finally, the planned activities for Phase 2, including an integrated human-in-the-loop simulation and two flight tests are briefly described.

  16. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project - Gen-4 and Gen-5 Radio Plans

    NASA Technical Reports Server (NTRS)

    Griner, James H.

    2014-01-01

    NASA's UAS Integration in the NAS project, has partnered with Rockwell Collins to develop a concept Control and Non-Payload Communication (CNPC) system prototype radio, operating on recently allocated UAS frequency spectrum bands. This prototype radio is being used to validate initial proposed performance requirements for UAS control communications. This presentation will give an overview of the current plans for the prototype radio development.

  17. Nitrogen-concentration control in GaNAs/AlGaAs quantum wells using nitrogen δ-doping technique

    SciTech Connect

    Mano, Takaaki; Jo, Masafumi; Kuroda, Takashi; Noda, Takeshi; Sugimoto, Yoshimasa; Sakuma, Yoshiki; Elborg, Martin; Sakoda, Kazuaki

    2014-05-15

    GaNAs/Al{sub 0.35}Ga{sub 0.65}As multiple quantum wells (MQWs) with nitrogen δ-doping were fabricated on GaAs (100) substrates by plasma-assisted molecular beam epitaxy. High controllability of nitrogen-concentrations in the MQWs was achieved by tuning nitrogen δ-doping time. The maximum nitrogen concentration in the MQWs was 2.8%. The MQWs exhibit intense, narrow photoluminescence emission.

  18. Electronic band structure calculation of GaNAsBi alloys and effective mass study

    NASA Astrophysics Data System (ADS)

    Habchi, M. M.; Ben Nasr, A.; Rebey, A.; El Jani, B.

    2013-11-01

    Electronic band structures of GaNxAs1-x-yBiy dilute nitrides-bismides have been determined theoretically within the framework of the band anticrossing (BAC) model and k ṡ p method. We have developed computer codes based on our extended BAC model, denoted (16 × 16), in which the dimension of the used states basis was equal to 16. We have investigated the band gap and the spin orbit splitting as a function of Bi composition for alloys lattice matched to GaAs. We have found that the substitution of As element by N and Bi impurities leads to a significant reduction of band gap energy by roughly 198 meV/%Bi. Meanwhile, spin orbit splitting increases by 56 meV/%Bi regardless N content. There is an excellent agreement between the model predictions and experiment reported in the literature. In addition, alloys compositions and oscillator strengths of transition energies have been calculated for GaNAsBi alloys which represent active zone of temperature insensitive (1.55 μm and 1.3 μm) wavelength laser diodes intended for optical fiber communications. A crossover at about 0.6 eV has occurred between Eg and Δso of GaN.039As.893Bi.068. When the quaternary is lattice mismatched to GaAs, resonance energy increases with Bi content if N content decreases. On the other hand, effective mass behavior of carriers at Γ point has been discussed with respect to alloy composition, k-directions and lattice mismatch.

  19. Suppression of non-radiative surface recombination by N incorporation in GaAs/GaNAs core/shell nanowires

    PubMed Central

    Chen, Shula L.; Chen, Weimin M.; Ishikawa, Fumitaro; Buyanova, Irina A.

    2015-01-01

    III-V semiconductor nanowires (NWs) such as GaAs NWs form an interesting artificial materials system promising for applications in advanced optoelectronic and photonic devices, thanks to the advantages offered by the 1D architecture and the possibility to combine it with the main-stream silicon technology. Alloying of GaAs with nitrogen can further enhance performance and extend device functionality via band-structure and lattice engineering. However, due to a large surface-to-volume ratio, III-V NWs suffer from severe non-radiative carrier recombination at/near NWs surfaces that significantly degrades optical quality. Here we show that increasing nitrogen composition in novel GaAs/GaNAs core/shell NWs can strongly suppress the detrimental surface recombination. This conclusion is based on our experimental finding that lifetimes of photo-generated free excitons and free carriers increase with increasing N composition, as revealed from our time-resolved photoluminescence (PL) studies. This is accompanied by a sizable enhancement in the PL intensity of the GaAs/GaNAs core/shell NWs at room temperature. The observed N-induced suppression of the surface recombination is concluded to be a result of an N-induced modification of the surface states that are responsible for the nonradiative recombination. Our results, therefore, demonstrate the great potential of incorporating GaNAs in III-V NWs to achieve efficient nano-scale light emitters. PMID:26100755

  20. Estudo de não gaussianidade nas anisotropias da RCF medidas Wmap

    NASA Astrophysics Data System (ADS)

    Andrade, A. P. A.; Wuensche, C. A.; Ribeiro, A. L. B.

    2003-08-01

    A investigação do campo de flutuações da Radiação Cósmica de Fundo (RCF) pode oferecer um importante teste para os modelos cosmológicos que descrevem a origem e a evolução das flutuações primordiais. De um lado, apresenta-se o modelo inflacionário que prevê um espectro de flutuações adiabáticas distribuídas segundo uma gaussiana e, de outro, os modelos de defeitos topológicos (dentre outros) que descrevem um mecanismo para a geração de flutuações de isocurvatura que obedecem a uma distribuição não gaussiana. Este trabalho tem como objetivo caracterizar traços do modelo não gaussiano de campo misto (entre flutuações adiabáticas e de isocurvatura) nos mapas do Wilkinson Microwave Anisotropy Probe (WMAP). Simulações das anisotropias da RCF no contexto de mistura indicam traços marcantes na distribuição das flutuações de temperatura, mesmo quando consideradas pequenas contribuições do campo de isocurvatura (da ordem de 0.001). O efeito da mistura entre os campos resulta na transferência de potência de flutuações em escalas angulares intermediárias para flutuações em pequenas escalas angulares. Este efeito pode ser caracterizado pela relação entre as amplitudes dos primeiros picos acústicos no espectro de potência da RCF. Neste trabalho, investigamos a contribuição do campo de isocurvatura, no contexto de mistura, sobre as observações recentes da RCF realizadas pelo WMAP. As previsões do modelo de campo misto, uma vez confrontadas com as observações em pequenas escalas angulares, podem ajudar a revelar a natureza das flutuações primordiais.

  1. 1.55 {mu}m GaAs/GaNAsSb/GaAs optical waveguides grown by radio frequency nitrogen plasma-assisted molecular beam epitaxy

    SciTech Connect

    Tan, K. H.; Yoon, S. F.; Loke, W. K.; Wicaksono, S.; Xu, Z.; Ng, T. K.; Lew, K. L.; Saadsaoud, N.; Zegaoui, M.; Decoster, D.; Chazelas, J.

    2008-03-17

    We demonstrate a 1.55 {mu}m GaAs/GaNAsSb/GaAs optical waveguide grown by molecular beam epitaxy as an alternative to the AlGaAs/GaAs system. The 0.4-{mu}m-thick GaNAsSb guiding layer contains {approx}3.5% of N and 9% of Sb, resulting in optical band gap of 0.88 eV. The refractive index of the GaNAsSb layer was measured from 800 to 1700 nm. The GaNAsSb layer has a refractive index value of 3.42 at 1.55 {mu}m wavelength. The propagation loss measured using the Fabry-Perot resonance method was found to be affected by nitrogen-related defect absorption.

  2. High-temperature operation of self-assembled GaInNAs/GaAsN quantum-dot lasers grown by solid-source molecular-beam epitaxy

    SciTech Connect

    Liu, C.Y.; Yoon, S.F.; Sun, Z.Z.; Yew, K.C.

    2006-02-20

    Self-assembled GaInNAs/GaAsN single layer quantum-dot (QD) lasers grown using solid-source molecular-beam epitaxy have been fabricated and characterized. Temperature-dependent measurements have been carried out on the GaInNAs QD lasers. The lowest obtained threshold current density in this work is {approx}1.05 kA/cm{sup 2} from a GaInNAs QD laser (50x1700 {mu}m{sup 2}) at 10 deg. C. High-temperature operation up to 65 deg. C was also demonstrated from an unbonded GaInNAs QD laser (50x1060 {mu}m{sup 2}), with high characteristic temperature of 79.4 K in the temperature range of 10-60 deg. C.

  3. Remotely Operated Aircraft (ROA) Impact on the National Airspace System (NAS) Work Package: Data Modeling and Sharing Perspective for Development of a Common Operating Picture

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This report documents analyses that were performed in support of Task #3 of Work Package #3 (WP3), ROA Impact on the NAS. The purpose of the overall work package was to determine if there are any serious issues that would prevent or prohibit ROA's flying in the NAS on a routine basis, and if so, what actions should be taken to address them. The purpose of Task #3 was to look at this problem from the perspective of data modeling and sharing.

  4. Is EMS communicating with the FCC?

    PubMed

    Johnson, M S; VanCott, C; Glass, C; Anderson, P B

    1989-07-01

    Radio communication problems in EMS run the spectrum from annoying to deadly. Dedicated radio frequencies for EMS, much like those exclusive to police and fire departments, are long overdue. PMID:10293680

  5. Minimum Capacity of NaS Battery according to Capacity of PV System in a Microgrid under 30 min Power Balancing Control

    NASA Astrophysics Data System (ADS)

    Shimakage, Toyonari; Sone, Akihito; Sumita, Jiro; Kato, Takeyoshi; Suzuoki, Yasuo

    On constructing a microgrid, it is essential to design capacity of photovoltaic power generation (PV) systems and storage batteries in accordance with a control target. In this study, we constructed a simulation model of energy control system in the microgrid used in the demonstration project. By using this model, we investigated the minimum capacity of NaS battery for different PV system capacities for keeping the target power imbalance within ±3% over 30 min. The main results are as follows. The microgrid involving 330-kW PV systems (corresponding to the actual system) needs a NaS battery capacity of at least approximately ±20kW, and PV systems with a capacity up to about 890kW can be integrated in the microgrid with a NaS battery capacity of ±500kW (corresponding to the actual system). We estimated the minimum capacity of NaS battery for different PV system capacities and clarified that the output behavior of the NaS battery and PAFC when supply and demand power imbalance over 30 min. exceeds the ±3% limit. We suggested the improved control model and showed that it is effective in decreasing the minimum capacity of NaS battery, although it has negative effects on the reduction of short-period power flow fluctuation at the grid-connection point.

  6. Incorporating the social dimension into hydrogeochemical investigations for rural development: the Bir Al-Nas approach for socio-hydrogeology

    NASA Astrophysics Data System (ADS)

    Re, Viviana

    2015-11-01

    A replicable multidisciplinary approach is presented for science-based groundwater management practices: Bir Al-Nas (Bottom-up IntegRated Approach for sustainabLe grouNdwater mAnagement in rural areaS). This approach provides a practical example of the concept of "socio-hydrogeology", a way of incorporating the social dimension into hydrogeological investigations, as reinforced by the translation of the Arabic bir al-nas: "the people's well". To achieve this, hydrogeologists act as "social hydrologists" during their monitoring activities, which often bring them into contact with local communities and end users (and polluters) of water. Not only can they retrieve reliable information about traditional know-how and local issues, but they can also change the public perception of science/scientists to create the basis for mutual collaboration and understanding in view of implementing improved integrated groundwater management. The final outcomes are expected to be an increased awareness of communities at the local level and a clear understanding of their water issues and needs from the very early stages of the investigation. Although the importance of using such methods in groundwater analysis and management is widely recognized, hydrogeological investigations are currently dominated by sectorial approaches that are easier to implement but less sustainable. The pressure of population growth, the shift towards more water-dependent economies, climate change and its impact on water availability will require scientists to use a more integrated approach, such as Bir Al-Nas, when dealing with increasing water pollution and water-scarcity issues.

  7. Alveolar Echinococcosis: Characterization of Diagnostic Antigen Em18 and Serological Evaluation of Recombinant Em18

    PubMed Central

    Sako, Yasuhito; Nakao, Minoru; Nakaya, Kazuhiro; Yamasaki, Hiroshi; Gottstein, Bruno; Lightowers, Marshall W.; Schantz, Peter M.; Ito, Akira

    2002-01-01

    The Echinococcus multilocularis protein Em18 is one of the most promising antigens for use in serodiagnosis of alveolar echinococcosis in human patients. Here we identify an antigenic relationship between Em18 and a 65-kDa immunodominant E. multilocularis surface protein previously identified as either EM10 or EmII/3. The NH2-terminal sequence of native Em18 was determined, revealing it to be a fragment of EM10. Experiments were undertaken to investigate the effect of proteinase inhibitors on the degradation of EM10 in crude extracts of E. multilocularis protoscoleces. Em18 was found to be the product of degradation of EM10 by cysteine proteinase. A recombinant Em18 (RecEm18, derived from 349K to 508K of EM10) was successfully expressed by using Escherichia coli expression system and then evaluated for use in serodiagnosis of alveolar echinococcosis. RecEm18 was recognized by 27 (87.1%) and 28 (90.3%) of 31 serum samples from clinically and/or pathologically confirmed alveolar echinococcosis patients by enzyme-linked immunosorbent assay and immunoblotting, respectively. Of 33 serum samples from cystic echinococcosis patients, 1 was recorded as having a weak positive reaction to RecEm18; however, none of the serum samples which were tested from neurocysticercosis patients (n = 10) or healthy people (n = 15) showed positive reactions. RecEm18 has the potential for use in the differential serodiagnosis of alveolar echinococcosis. PMID:12149326

  8. The CSM testbed software system: A development environment for structural analysis methods on the NAS CRAY-2

    NASA Technical Reports Server (NTRS)

    Gillian, Ronnie E.; Lotts, Christine G.

    1988-01-01

    The Computational Structural Mechanics (CSM) Activity at Langley Research Center is developing methods for structural analysis on modern computers. To facilitate that research effort, an applications development environment has been constructed to insulate the researcher from the many computer operating systems of a widely distributed computer network. The CSM Testbed development system was ported to the Numerical Aerodynamic Simulator (NAS) Cray-2, at the Ames Research Center, to provide a high end computational capability. This paper describes the implementation experiences, the resulting capability, and the future directions for the Testbed on supercomputers.

  9. UAS Integration into the NAS: Detect and Avoid Display Evaluations in Support of SC-228 MOPS Development

    NASA Technical Reports Server (NTRS)

    Fern, Lisa; Rorie, Conrad; Shively, Jay

    2015-01-01

    This presentation provides an overview of the work the Human Systems Integration (HSI) sub-project has done on detect and avoid (DAA) displays while working on the UAS Integration into the NAS project. Much of the work has been used to support the ongoing development of minimum operational performance standards (MOPS) for UAS by RTCA Special Committee 228. The design and results of three different human-in-the-loop simulations are discussed, with particular emphasis on the role of the UAS pilot in the Self Separation Timeline.

  10. The European Mobile System (EMS)

    NASA Technical Reports Server (NTRS)

    Jongejans, A.; Rogard, R.; Mistretta, I.; Ananasso, F.

    1993-01-01

    The European Space Agency is presently procuring an L band payload in order to promote a regional European L band system coping with the specific needs of the European market. The payload, and the two communications systems to be supported, are described below. The potential market for EMS in Europe is discussed.

  11. Observacoes do Cometa de Halley no Continuo de 22 GHz E 44 GHz, E NA Raia Maser de Vapor de H20 EM 22.2 GHz

    NASA Astrophysics Data System (ADS)

    Abraham, Z.; Scalise, E., Jr.; Botti, L. C. L.; Cancoro, A. C. O.; Monteiro Do Vale, J. L.; del Ciampo, L. F.; Tateyama, C. E.; Vilas Boas, J. W. S.; Homor, J. L.; Kaufmann, P.

    1987-05-01

    0 cometa de Halley foi observado no contínuo nas frequencias de 22 GHz e 44 GHz no Observatório de Itapetinga, Brasil, no período Fevereiro-Abril de 1986. 0 cometa foi detetado em ambas frequẽncias, apresentando variabilidade corn escalas de tempo de horas. Cálculos teóricos mostram que a radicão não pode ser devida a transicões livre-livre na região ionizada resultante da interacão do cometa corn 0 vento solar. A emissão seria então devida à radiacão térmica dos gráos da coma do cometa, cuja densidade também foi variável em intervalo de horas. Não foi detetada emissão maser de H2O maior que 4 Jy.

  12. Cohort Profile: The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry).

    PubMed

    Gatz, Margaret; Harris, Jennifer R; Kaprio, Jaakko; McGue, Matt; Smith, Nicholas L; Snieder, Harold; Spiro, Avron; Butler, David A

    2015-06-01

    The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry) is a comprehensive registry of White male twin pairs born in the USA between 1917 and 1927, both of the twins having served in the military. The purpose was medical research and ultimately improved clinical care. The cohort was assembled in the early 1960s with identification of approximately 16,000 twin pairs, review of service records, a brief mailed questionnaire assessing zygosity, and a health survey largely comparable to questionnaires used at that time with Scandinavian twin registries. Subsequent large-scale data collection occurred in 1974, 1985 and 1998, repeating the health survey and including information on education, employment history and earnings. Self-reported data have been supplemented with mortality, disability and medical data through record linkage. Potential collaborators should access the study website [http://www.iom.edu/Activities/Veterans/TwinsStudy.aspx] or e-mail the Medical Follow-up Agency at [Twins@nas.edu]. Questionnaire data are being prepared for future archiving with the National Archive of Computerized Data on Aging (NACDA) at the Inter-University Consortium for Political and Social Research (ICPSR), University of Michigan, MI. PMID:25183748

  13. TlGaInNAs/GaAs double quantum well structures: Effect of barrier layers and substrate orientation

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, D.; Matsumoto, T.; Fujiwara, A.; Hasegawa, S.; Asahi, H.

    2007-04-01

    The quinary TlGaInNAs-based double quantum well (DQW) structures were grown on GaAs substrates by electron cyclotron resonance (ECR)-MBE and the samples were probed by secondary ion mass spectroscopy (SIMS). Light emitting diodes (LEDs) were fabricated using these DQW wafers and their electroluminescence (EL) behaviors were studied at different temperatures. The effects of different barrier layers and substrate orientations on the amount of Tl incorporation and on the temperature dependency of the EL peak wavelengths of the LEDs were studied. Higher incorporation of Tl into the quantum well (QW) region and the ensuing change in the temperature dependency of the peak wavelengths owing to the TlGaAs barrier layer are reported. GaAs substrates having (3 1 1)B orientation were found to allow more Tl incorporation as compared to (1 0 0) and (3 1 1)A oriented substrates. The LEDs fabricated out of the TlGaInNAs/TlGaAs/(3 1 1)B GaAs DQW structures showed the least temperature dependency of the EL peak wavelengths exemplifying the usefulness of Tl in the QW as well as barrier region.

  14. Simulation and optimization of current and lattice matching double-junction GaNAsP/Si solar cells

    NASA Astrophysics Data System (ADS)

    Nacer, S.; Aissat, A.

    2016-01-01

    This paper deals with theoretical investigation of the performance of current and lattice matched GaNxAsyP1-x-y/Si double-junction solar cells. The nitrogen and arsenic concentrations ensuring lattice matching to Si are determined. The band gap of GaNAsP is calculated using the band anti-crossing model. Calculations were performed under 1-sun AM1.5 using the one diode ideal model. Impact of minor carrier lifetime and surface recombination in the top sub-cell on the cell performances is analyzed. Optimum compositions of the top sub-cell have been identified (x = 4.5%, y = 11.5% and Eg = 1.68 eV). The simulation results predict, for the optimized GaNAsP/Si double-junction solar cell, a short circuit current Jsc = 20 mA/cm2, an open circuit voltage Voc = 1.95 V, and a conversion efficiency η = 37.5%.

  15. The effect of cathode felt geometries on electrochemical characteristics of sodium sulfur (NaS) cells: Planar vs. tubular

    NASA Astrophysics Data System (ADS)

    Kim, Goun; Park, Yoon-Cheol; Lee, Younki; Cho, Namung; Kim, Chang-Soo; Jung, Keeyoung

    2016-09-01

    Two sodium sulfur (NaS) cells, one with a planar design and the other with a tubular design, were subject to discharge-charge cycles in order to investigate the effect of cathode felt geometries on electrochemical characteristics of NaS cells. Their discharge-charge behaviors over 200 cycles were evaluated at the operation temperature of 350 °C with the current densities of 100 mA cm-2 for discharge and 80 mA cm-2 for charge. The results showed that the deviation from theoretical open circuit voltage changes of a planar cell was smaller than those of a tubular cell resulting in potential specific power loss reduction during operation. In order to understand the effect, a three dimensional statistically representative matrix for a cathode felt has been generated using experimentally measured data. It turns out that the area specific fiber number density in the outer side area of a tubular cathode felt is smaller than that of a planar felt resulting in occurrence of larger voltage drops via retarded convection of cathode melts during cell operation.

  16. Impact of Nitrogen on the Lasing Characteristic of 1.31 μm GaInNAs Quantum Well Lasers

    NASA Astrophysics Data System (ADS)

    Manaf, Nor Azlian Abdul; Alias, Mohd Sharizal; Mitani, Sufian Mousa; Maskuriy, Farha; Sabtu, Idris; Yahya, Mohd Razman

    2011-05-01

    A comprehensive study has been done to investigate the lasing characteristic of 1.31 μm GaInNAs quantum well (QW) lasers. We have varied the nitrogen (N) compositions of GaInNAs QW from 1.0 to 2.0 percentages (%) with a stepped of 0.2 %. Significant improvement of lasing wavelength, emission efficiency and output power were demonstrated with higher N in GaInNAs QW. The emission wavelength red-shifted when the N% enlarge. As formerly known, the band gap of GaInNAs is controlled by adjusting the ratio of group III (Ga, In) or group V (N, As) materials. As the N increased, the band gap will be reduced and thus increasing the emission wavelength. The average ratio of the red-shifted is 92.49 nm per N %. We believed that that the optical quality of the GaInNAs QW depends on N% and total number of N incorporated in the QW. The discussion on the devices performance will be reported further.

  17. Three of Four GlnR Binding Sites Are Essential for GlnR-Mediated Activation of Transcription of the Amycolatopsis mediterranei nas Operon

    PubMed Central

    Wang, Ying; Wang, Jing-Zhi; Shao, Zhi-Hui; Yuan, Hua; Lu, Yin-Hua; Jiang, Wei-Hong

    2013-01-01

    In Amycolatopsis mediterranei U32, genes responsible for nitrate assimilation formed one operon, nasACKBDEF, whose transcription is induced by the addition of nitrate. Here, we characterized GlnR as a direct transcriptional activator for the nas operon. The GlnR-protected DNA sequences in the promoter region of the nas operon were characterized by DNase I footprinting assay, the previously deduced Streptomyces coelicolor double 22-bp GlnR binding consensus sequences comprising a1, b1, a2, and b2 sites were identified, and the sites were then mutated individually to test their roles in both the binding of GlnR in vitro and the GlnR-mediated transcriptional activation in vivo. The results clearly showed that only three GlnR binding sites (a1, b1, and b2 sites) were required by GlnR for its specific binding to the nas promoter region and efficient activation of the transcription of the nas operon in U32, while the a2 site seemed unnecessary. PMID:23543714

  18. Remotely Operated Aircraft (ROA) Impact on the National Airspace System (NAS) Work Package, 2005: Composite Report on FAA Flight Plan and Operational Evaluation Plan. Version 7.0

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The purpose of this document is to present the findings that resulted from a high-level analysis and evaluation of the following documents: (1) The OEP (Operational Evolution Plan) Version 7 -- a 10-year plan for operational improvements to increase capacity and efficiency in U.S. air travel and transport and other use of domestic airspace. The OEP is the FAA commitment to operational improvements. It is outcome driven, with clear lines of accountability within FAA organizations. The OEP concentrates on operational solutions and integrates safety, certification, procedures, staffing, equipment, avionics and research; (2) The Draft Flight Plan 2006 through 2010 -- a multi-year strategic effort, setting a course for the FAA through 2001, to provide the safest and most efficient air transportation system in the world; (3) The NAS System Architecture Version 5 -- a blueprint for modernizing the NAS and improving NAS services and capabilities through the year 2015; and (4) The NAS-SR-1000 System Requirements Specification (NASSRS) -- a compilation of requirements which describe the operational capabilities for the NAS. The analysis is particularly focused on examining the documents for relevance to existing and/or planned future UAV operations. The evaluation specifically focuses on potential factors that could materially affect the development of a commercial ROA industry, such as: (1) Design limitations of the CNS/ATM system, (2) Human limitations, The information presented was taken from program specifications or program office lead personnel.

  19. Queda dos homicídios em São Paulo, Brasil: uma análise descritiva

    PubMed Central

    Peres, Maria Fernanda Tourinho; Vicentin, Diego; Nery, Marcelo Batista; de Lima, Renato Sérgio; de Souza, Edinilsa Ramos; Cerda, Magdalena; Cardia, Nancy; Adorno, e Sérgio

    2012-01-01

    Objetivo Descrever a evolução da mortalidade por homicídios no Município de São Paulo segundo tipo de arma, sexo, raça ou cor, idade e áreas de exclusão/inclusão social entre 1996 e 2008. Métodos Estudo ecológico de série temporal. Os dados sobre óbitos ocorridos no Município foram coletados da base de dados do Programa de Aprimoramento das Informações sobre Mortalidade, seguindo a Classificação Internacional de Doenças, Décima Revisão (CID-10). Foram calculadas as taxas de mortalidade por homicídio (TMH) para a população total, por sexo, raça ou cor, faixa etária, tipo de arma e área de exclusão/inclusão social. As TMH foram padronizadas por idade pelo método direto. Foram calculados os percentuais de variação no período estudado. Para as áreas de exclusão/inclusão social foram calculados os riscos relativos de morte por homicídio. Resultados As TMH apresentaram queda de 73,7% entre 2001 e 2008. Foi observada redução da TMH em todos os grupos analisados, mais pronunciada em homens (−74,5%), jovens de 15 a 24 anos (−78,0%) e moradores de áreas de exclusão social extrema (−79,3%). A redução ocorreu, sobretudo, nos homicídios cometidos com armas de fogo (−74,1%). O risco relativo de morte por homicídio nas áreas de exclusão extrema (tendo como referência áreas com algum grau de exclusão social) foi de 2,77 em 1996, 3,9 em 2001 e 2,13 em 2008. Nas áreas de alta exclusão social, o risco relativo foi de 2,07 em 1996 e 1,96 em 2008. Conclusões Para compreender a redução dos homicídios no Município, é importante considerar macrodeterminantes que atingem todo o Município e todos os subgrupos populacionais e microdeterminantes que atuam localmente, influenciando de forma diferenciada os homicídios com armas de fogo e os homicídios na população jovem, no sexo masculino e em residentes em áreas de alta exclusão social. PMID:21390415

  20. População nuclear e extranuclear em rádio-galáxias

    NASA Astrophysics Data System (ADS)

    Raimann, D. I.; Storchi-Bergmann, T.; Quintana, H.; Alloin, D.; Hunstead, R.; Wisotzki, L.

    2003-08-01

    A natureza do contínuo UV/ótico em rádio-galáxias é muito importante para o seu entendimento. Em baixos redshifts existem evidências de que muitas delas são dominadas no ótico por luz de estrelas velhas, características de galáxias early-type e em altos redshifts a característica dominante é um excesso de luz no UV, freqüentemente associado com estruturas que estão alinhadas aos eixos das estruturas rádio em grande escala. Inicialmente esse excesso foi interpretado como devido a episódios intensos de formação estelar nas galáxias hospedeiras. Entretanto, as descobertas dos alinhamentos entre as estruturas UV e rádio modificaram essa idéia. Foi proposto que a formação estelar é iniciada pela passagem do jato rádio através do meio interestelar das galáxias hospedeiras. A natureza do excesso UV começou a ser compreendida em um estudo detalhado do continuo ótico da 3C321, onde se concluiu que o contínuo desta galáxia tem origem multicomponente, com contribuições de populações velhas e intermediárias, de luz espalhada oriunda de um quasar obscurecido e do contínuo nebular. No presente trabalho estudamos a população nuclear e extranuclear de uma amostra de 24 rádio-galáxias, utilizando espectros óticos de fenda longa, com alta razão sinal/ruído. Através do método de síntese espectral de populações estelares, foram estimadas as contribuições de populações estelares de diferentes idades (e de um contínuo tipo lei de potência devido a um AGN, FC) para a luz integrada das galáxias, em 4020Å. As principais conclusões deste trabalho são: apenas quatro dos objetos estudados têm contribuições significativas (maiores do que 10%) das populações de 100 milhões de anos ou mais jovens (ou de FC) ao longo da região espacial estudada (6 kpc centrais); nenhuma das rádio-galáxias de tipo FRI estudadas tem contribuição significativa destas populações ao longo desta região; duas (de oito) de tipo FRII tem contribui

  1. Incorporation model of N into GaInNAs alloys grown by radio-frequency plasma-assisted molecular beam epitaxy

    SciTech Connect

    Aho, A.; Korpijärvi, V.-M.; Tukiainen, A.; Puustinen, J.; Guina, M.

    2014-12-07

    We present a Maxwell-Boltzmann electron energy distribution based model for the incorporation rate of nitrogen into GaInNAs grown by molecular beam epitaxy (MBE) using a radio frequency plasma source. Nitrogen concentration is predicted as a function of radio-frequency system primary resistance, N flow, and RF power, and group III growth rate. The semi-empirical model is shown to be repeatable with a maximum error of 6%. The model was validated for two different MBE systems by growing GaInNAs on GaAs(100) with variable nitrogen composition of 0%–6%.

  2. Reactive Microcontact Printing of DNA Probes on (DMA-NAS-MAPS) Copolymer-Coated Substrates for Efficient Hybridization Platforms.

    PubMed

    Castagna, Rossella; Bertucci, Alessandro; Prasetyanto, Eko Adi; Monticelli, Marco; Conca, Dario Valter; Massetti, Matteo; Sharma, Parikshit Pratim; Damin, Francesco; Chiari, Marcella; De Cola, Luisa; Bertacco, Riccardo

    2016-04-01

    High-performing hybridization platforms fabricated by reactive microcontact printing of DNA probes are presented. Multishaped PDMS molds are used to covalently bind oligonucleotides over a functional copolymer (DMA-NAS-MAPS) surface. Printed structures with minimum width of about 1.5 μm, spaced by 10 μm, are demonstrated, with edge corrugation lower than 300 nm. The quantification of the immobilized surface probes via fluorescence imaging gives a remarkable concentration of 3.3 × 10(3) oligonucleotides/μm(2), almost totally active when used as probes in DNA-DNA hybridization assays. Indeed, fluorescence and atomic force microscopy show a 95% efficiency in target binding and uniform DNA hybridization over printed areas. PMID:26972953

  3. Theoretical analysis of 1.55 μm emitting GaInNAs QD's on different substrates

    NASA Astrophysics Data System (ADS)

    Tomić, S.; Jones, T. S.

    2008-04-01

    We present a theoretical study which compares the electronic and optical properties of dilute nitrogen GaInNAs quantum dots (QD) on two different substrates, GaAs and InP. The calculations are based on a 10 band kṡp band-anti-crossing (BAC) Hamiltonian, incorporating valence, conduction and nitrogen-induced bands. We show that 1.55 μm emission can be achieved on both substrates through appropriate tailoring of the QD size. On GaAs, the dominant dipole matrix element is the e and e light polarization, whereas on InP substrate, the dominant component is the e light polarization. Our results also identifiy the different In and N QD compositions required for long-wavelength emission on both substrates.

  4. Study of nitrogen incorporation into GaInNAs: The role of growth temperature in molecular beam epitaxy

    SciTech Connect

    Korpijaervi, V.-M.; Aho, A.; Tukiainen, A.; Laakso, A.; Guina, M.; Laukkanen, P.; Tuominen, M.

    2012-07-15

    GaInNAs has an important impact on developing GaAs-based optoelectronics and multijunction solar cells, but the complex nature of the nitrogen incorporation into GaInAs is still not fully understood. By combining x-ray diffraction, photoluminescence, reflection high-energy electron diffraction, and photoelectron spectroscopy measurements, we show that nitrogen incorporation is enhanced with increasing growth temperature in the range of 300-450 Degree-Sign C. We study the growth front and show that the surface reconstruction is (1 Multiplication-Sign 3) regardless of growth temperature in this range. The enhanced nitrogen incorporation can be modeled as a thermally activated process with activation energy of about 0.1 eV.

  5. LNTgate: How scientific misconduct by the U.S. NAS led to governments adopting LNT for cancer risk assessment.

    PubMed

    Calabrese, Edward J

    2016-07-01

    This paper provides a detailed rebuttal to the letter of Beyea (2016) which offered a series of alternative interpretations to those offered in my article in Environmental Research (Calabrese, 2015a) concerning the role of the U.S. National Academy of Sciences (NAS) Biological Effects of Atomic Radiation (BEAR) I Committee Genetics Panel in the adoption of the linear dose response model for cancer risk assessment. Significant newly uncovered evidence is presented which supports and extends the findings of Calabrese (2015a), reaffirming the conclusion that the Genetics Panel should be evaluated for scientific misconduct for deliberate misrepresentation of the research record in order to enhance an ideological agenda. This critique documents numerous factual errors along with extensive and deliberate filtering of information in the Beyea letter (2016) that leads to consistently incorrect conclusions and an invalid general perspective. PMID:27131569

  6. Carrier dynamics in Ga(NAsP)/Si multi-quantum well heterostructures with varying well thickness

    NASA Astrophysics Data System (ADS)

    Shakfa, M. K.; Woscholski, R.; Gies, S.; Wegele, T.; Wiemer, M.; Ludewig, P.; Jandieri, K.; Baranovskii, S. D.; Stolz, W.; Volz, K.; Heimbrodt, W.; Koch, M.

    2016-05-01

    Time-resolved photoluminescence (TR-PL) measurements have been performed in Ga(NAsP)/(BGa)(AsP) multi-quantum well heterostructures (MQWHs) with different well thicknesses. The studied structures have been pseudomorphically grown on Si substrates by metal organic vapor phase epitaxy (MOVPE) with an N content of about 7%. Experimental results reveal a shortening in the PL decay time with increasing QW thickness, meanwhile, accompanied by a decrease in the PL intensity. We attribute this behavior to an increasing non-radiative recombination rate for broader QWs which arises from an increasing number of defects in the QW material. The emission-energy distribution of the PL decay time is studied at various temperatures. The PL decay time strongly depends on the emission energy at low temperatures and becomes emission-energy-independent close to room temperature. This is discussed in terms of the carrier localization in the studied structures.

  7. 1.22 {mu}m GaInNAs Saturable Absorber Mirrors with Tailored Recovery Time

    SciTech Connect

    Puustinen, Janne; Guina, Mircea; Korpijaervi, Ville-Markus; Tukiainen, Antti; Kivistoe, Samuli; Pessa, Markus; Marcinkevicius, Saulius

    2010-11-10

    The effect of in-situ N-ion irradiation on the recombination dynamics of GaInNAs/GaAs semiconductor saturable absorber mirrors has been studied. The samples were fabricated by molecular beam epitaxy using a radio frequency plasma source for nitrogen incorporation in the absorber layers as well as for the irradiation. The recombination dynamics of irradiated samples were studied by pump-probe measurements. The recombination time of the absorbers could be reduced by increasing the irradiation time. The effect of the reduced recombination time on the pulse dynamics of a mode-locked laser setup was studied with a Bi-doped fibre laser. The pulse quality was found to improve with increased irradiation time and reduced recombination time, demonstrating the potential of the in-situ irradiation method for device applications.

  8. Ondas de choque em jatos de quasares e objetos BL Lacertae

    NASA Astrophysics Data System (ADS)

    Melo, F. E.; Botti, L. C. L.

    2003-08-01

    Este trabalho é parte de um projeto que vem sendo realizado há dois anos no CRAAM, cujos objetivos principais são analisar e aplicar um modelo generalizado de ondas de choque em jatos relativísticos de plasma, presentes em quasares e objetos BL Lacertae, para explicar a variabilidade observada nestes objetos. O método consiste em uma decomposição de curvas de luz em séries de explosões similares, em várias freqüências, baseando-se em uma evolução espectro-temporal média das explosões. A partir da evolução média, um ajuste de cada explosão é feito com base em equações empíricas, modificando-se apenas parâmetros específicos de cada explosão. Inicialmente o modelo foi aplicado ajustando-se as curvas de luz a explosões delineadas por uma evolução do choque em três estágios, segundo a predominância do processo de emissão: síncrotron, Compton e adiabático. Entretanto, nesta nova fase de projeto, visando uma parametrização mais concisa, uma otimização do algoritmo de ajuste e uma convergência mais rápida, a formulação para cada evento foi assumida com uma evolução em apenas dois estágios: subida e descida. Isto possibilitou uma ótima delineação das curvas de luz das fontes OV236, OJ287, 3C273 e BL Lac, entre 1980 e 2000, nas freqüências 4.8, 8.0, 14.5 e 22 GHz, utilizando-se dados do Observatório da Universidade de Michigan, do Observatório do Itapetinga (Atibaia SP) e do Observatório Metsähovi. Como conclusões importantes, verificou-se que: os parâmetros ajustados descrevem o comportamento do jato; os valores do índice que descreve a expansão do jato sugerem que o mesmo se expande de uma forma não-cônica; o campo magnético é turbulento atrás da frente de choque; e as peculiaridades das explosões são devidas à influência de grandezas tais como o coeficiente da distribuição espectral de energia dos elétrons, a intensidade de campo magnético e o fator de feixe Doppler, no início do choque.

  9. DOE/EM Criticality Safety Needs Assessment

    SciTech Connect

    Westfall, Robert Michael; Hopper, Calvin Mitchell

    2011-02-01

    The issue of nuclear criticality safety (NCS) in Department of Energy Environmental Management (DOE/EM) fissionable material operations presents challenges because of the large quantities of material present in the facilities and equipment that are committed to storage and/or material conditioning and dispositioning processes. Given the uncertainty associated with the material and conditions for many DOE/EM fissionable material operations, ensuring safety while maintaining operational efficiency requires the application of the most-effective criticality safety practices. In turn, more-efficient implementation of these practices can be achieved if the best NCS technologies are utilized. In 2002, DOE/EM-1 commissioned a survey of criticality safety technical needs at the major EM sites. These needs were documented in the report Analysis of Nuclear Criticality Safety Technology Supporting the Environmental Management Program, issued May 2002. Subsequent to this study, EM safety management personnel made a commitment to applying the best and latest criticality safety technology, as described by the DOE Nuclear Criticality Safety Program (NCSP). Over the past 7 years, this commitment has enabled the transfer of several new technologies to EM operations. In 2008, it was decided to broaden the basis of the EM NCS needs assessment to include not only current needs for technologies but also NCS operational areas with potential for improvements in controls, analysis, and regulations. A series of NCS workshops has been conducted over the past years, and needs have been identified and addressed by EM staff and contractor personnel. These workshops were organized and conducted by the EM Criticality Safety Program Manager with administrative and technical support by staff at Oak Ridge National Laboratory (ORNL). This report records the progress made in identifying the needs, determining the approaches for addressing these needs, and assimilating new NCS technologies into EM

  10. Estudo de soluções locais e cosmológicas em teorias do tipo tensor-escalar

    NASA Astrophysics Data System (ADS)

    Silva E Costa, S.

    2003-08-01

    Teorias do tipo tensor-escalar são a mais simples extensão possí vel da Relatividade Geral. Nessas teorias, cujo modelo padrão é a teoria de Brans-Dicke, a curvatura do espaço-tempo, descrita por componentes tensoriais, aparece acoplada a um campo escalar que, de certo modo, representa uma variação na constante de acoplamento da gravitação. Tais teorias apresentam soluções locais e cosmológicas que, em determinados limites, recaem nas apresentadas pela Relatividade Geral, mas que em outros limites trazem novidades, tais como conseqüências observacionais da evolução de flutuações primordiais distintas daquelas previstas pela Relatividade Geral (ver, por ex., Nagata et al., PRD 66, p. 103510 (2002)). Graças a esta possibilidade de trazer à luz novidades em relação à gravitação, teorias do tipo tensor-escalar podem ser vistas como um interessante campo alternativo de pesquisas para soluções dos problemas de massa faltante (ou escura) e/ou energia escura. Seguindo tal linha, este trabalho, ainda em sua fase inicial, apresenta soluções gerais de teorias do tipo tensor-escalar para diversas situações, verificando-se em que consiste a divergência dessas soluções dos casos tradicionais possí veis na Relatividade Geral. Como exemplos das soluções aqui apresentadas pode-se destacar uma expressão geral para diferentes soluções cosmológicas englobando diferentes tipos de matéria (representados por diferentes equações de estado), e a expressão para uma solução local representando um buraco negro com rotação, similar à solução de Kerr da Relatividade Geral. Por fim, é importante ressaltar que, embora aqui apresentem-se poucos resultados novos, na literatura sobre o assunto a maior parte das soluções apresentadas limita-se a uns poucos casos especí ficos, tal como soluções cosmológicas apenas com curvatura nula, e que mesmo as soluções disponí veis são, em geral, pouco divulgadas e, portanto, pouco conhecidas, e

  11. Evolução química em galáxias compactas azuis (BCGs)

    NASA Astrophysics Data System (ADS)

    Lanfranchi, G. A.; Matteucci, F.

    2003-08-01

    Neste trabalho, a formação estelar e evolução quí mica em galáxias Compactas Azuis (Blue Compact Galaxies - BCGs) foram estudadas através da comparação de previsões de modelos de evolução quí mica a várias razões de abundância quí mica observadas nestas galáxias. Modelos detalhados com recentes dados de nucleossí ntese e que levam em consideração o papel desempenahdo por supernovas de ambos os tipos (II e Ia) na evolução galáctica foram desenvolvidos para as BCGs permitindo seguir a evolução de vários elementos quí micos (H, D, He, C, N, O, Mg, Si, S, Ca, e Fe). O modelo é caracterizado pelas prescrições adotadas para a formação estelar, a qual ocorre em vários surtos de atividade separados por longos perí odos quiescentes. Após ajustar os melhores modelos aos dados observacionais, as previsões destes modelos foram comparadas também a razões de abundância observadas em sistemas Damped Lyman alpha (DLAs) e a origem do N (primária ou secundária) foi discutida. Alguns dos resultados obtidos são: i) as razões de abundância observadas nas BCGs são reproduzidas por modelos com 2 a 7 surtos de formação estelar com eficiência entre n = 0.2-0.9 Gano-1; ii) os baixos valores de N/O observados nestas galáxias são um resultado natural de uma formação estelar em surtos; iii) os modelos para BCGs podem reproduzir os dados dos DLAs, iv) uma quantidade "baixa" de N primário produzido em estrelas de alta massa pode ser uma explicação para os baixos valores de [N/a] observados em DLAs.

  12. Effect of multilayer barriers on the optical properties of GaInNAs single quantum-well structures grown by metalorganic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Sun, H. D.; Clark, A. H.; Calvez, S.; Dawson, M. D.; Kim, K. S.; Kim, T.; Park, Y. J.

    2005-07-01

    We report on the effects of combined strain-compensating and strain-mediating layers of various widths on the optical properties of 1.3 μm GaInNAs/GaAs single quantum well structures grown by metalorganic vapor phase epitaxy (MOVPE). While the emission wavelength of GaInNAs/GaAs quantum wells can be redshifted by the adoption of strain-compensated GaNAs layers, the material quality is degraded by the increased stress at the well/barrier interface. This detrimental effect can be cured by inserting a strain-mediating InGaAs layer between them. Contrary to what is expected, however, the emission wavelength is blueshifted by the insertion of the InGaAs layer, which is attributed to the reduced N incorporation due to the improved interface quality. Our results indicate that the optical properties of MOVPE-grown GaInNAs/GaAs quantum wells can be optimized in quantum efficiency and emission wavelength by combination of strain-compensating and strain-mediating layers with suitable characteristics.

  13. Enhancement of photoluminescence from GaInNAsSb quantum wells upon annealing: improvement of material quality and carrier collection by the quantum well.

    PubMed

    Baranowski, M; Kudrawiec, R; Latkowska, M; Syperek, M; Misiewicz, J; Sarmiento, T; Harris, J S

    2013-02-13

    In this study we apply time resolved photoluminescence and contactless electroreflectance to study the carrier collection efficiency of a GaInNAsSb/GaAs quantum well (QW). We show that the enhancement of photoluminescence from GaInNAsSb quantum wells annealed at different temperatures originates not only from (i) the improvement of the optical quality of the GaInNAsSb material (i.e., removal of point defects, which are the source of nonradiative recombination) but it is also affected by (ii) the improvement of carrier collection by the QW region. The total PL efficiency is the product of these two factors, for which the optimal annealing temperatures are found to be ~700 °C and ~760 °C, respectively, whereas the optimal annealing temperature for the integrated PL intensity is found to be between the two temperatures and equals ~720 °C. We connect the variation of the carrier collection efficiency with the modification of the band bending conditions in the investigated structure due to the Fermi level shift in the GaInNAsSb layer after annealing. PMID:23306016

  14. School Budget Hold'em Facilitator's Guide

    ERIC Educational Resources Information Center

    Education Resource Strategies, 2012

    2012-01-01

    "School Budget Hold'em" is a game designed to help school districts rethink their budgeting process. It evolved out of Education Resource Strategies' (ERS) experience working with large urban districts around the country. "School Budget Hold'em" offers a completely new approach--one that can turn the budgeting process into a long-term visioning…

  15. View of Spacelab engineering Model (EM)

    NASA Technical Reports Server (NTRS)

    1981-01-01

    View of Spacelab engineering Model (EM) as it is being brought in the O and C bldg at Kenndey Space Center (27464); view of the EM as it is being offloaded from the C-54 aircraft. Kennedy Space Center alternative photo number is 108-KSC-80-OC-666 (27465); model taken out to launch pad (27466).

  16. EM international activities. February 1997 highlights

    SciTech Connect

    1997-02-01

    EM International Highlights is a brief summary of on-going international projects within the Department of Energy`s Office of Environmental Management (EM). This document contains sections on: Global Issues, activities in Western Europe, activities in central and Eastern Europe, activities in Russia, activities in Asia and the Pacific Rim, activities in South America, activities in North America, and International Organizations.

  17. GaInNAs/Ge (1.10/0.67 eV) double-junction solar cell grown by metalorganic chemical vapor deposition for high efficiency four-junction solar cell application

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaobin; Chen, Bingzhen; Pan, Xu; Wang, Lei; Ma, Difei; Zhang, Yang; Yang, Cuibai; Wang, Zhiyong

    2015-12-01

    GaInNAs materials with narrow bandgaps of 1.10 eV have been grown on a Ge substrate by metalorganic chemical vapor deposition to fabricate GaInNAs/Ge (1.10/0.67 eV) double-junction solar cells. We have studied the photovoltaic characteristics and the external quantum efficiencies of the double-junction cells with various annealing conditions and different GaInNAs base layer thicknesses. The best external quantum efficiency is obtained from the double-junction cell with a 1170 nm thick GaInNAs base layer annealed at 675 °C for 30 min. Under AM1.5G illumination, the best double-junction cell has a short circuit current density (J SC) as 23.63 mA cm-2, which is dominated by the J SC of the GaInNAs subcell.

  18. Effects of rapid thermal annealing conditions on GaInNAs band gap blueshift and photoluminescence intensity

    SciTech Connect

    Liverini, V.; Rutz, A.; Keller, U.; Schoen, S.

    2006-06-01

    We have studied the effects of various conditions of rapid thermal annealing (RTA) on 10 nm GaInNAs/GaAs single quantum wells (SQWs) with fixed indium concentration and increasing nitrogen content to obtain photoluminescence (PL) in the telecom wavelength regime of 1.3 and 1.5 {mu}m. Specifically, we analyzed the results of annealing for a fixed short time but at different temperatures and for longer times at a fixed temperature. In all experiments, InGaAs SQWs with the same In concentration were used as references. For both RTA conditions, the well-known blueshift of the band gap energy and the PL intensity improvement show trends that reveal that these are unrelated effects. At high RTA temperatures the PL efficiency reaches a maximum and then drops independently of N content. On the contrary, the blueshift experiences a rapid increase up to 700 deg. C (strong blueshift regime) and it saturates above this temperature (weak blueshift regime). Both these blueshift regimes are related to the nitrogen content in the SQWs but in different ways. In the strong blueshift regime, we could obtain activation energy for the blueshift process in the range of 1.25 eV, which increases with N content. Analysis with high-resolution x-ray diffraction (HRXRD) shows that the blueshift experienced in this regime is not due to a stoichiometric change in the QW. In the weak blueshift regime, the blueshift, which is only partly due to In outdiffusion, saturates more slowly the higher the N content. Annealing at the same temperature (600 deg. C) for a longer time shows that the blueshift saturates earlier than the PL intensity and that samples with higher nitrogen experience a larger blueshift. Only a small In outdiffusion for annealing at high temperatures (>650 deg. C) and long duration was observed. However, this modest stoichiometric change does not explain the large blueshift experienced by the GaInNAs SQWs. We conclude that the mechanism responsible for the drastic blueshift after

  19. EM International, July 1994, Volume 2

    SciTech Connect

    Not Available

    1994-10-01

    The Office of Environmental Management (EM) at the Department of Energy (DOE) is seeking out and leveraging foreign technology, data, and resources in keeping with EM`s mandate to protect public health and the environment through the safe and cost-effective remediation of the Department`s nuclear weapons sites. EM works closely with foreign governments, industry, and universities to obtain innovative environmental technologies, scientific and engineering expertise, and operations experience that will support EM`s objectives. Where appropriate, these international resources are used to manage the more urgent risks at our sites, secure a safe workplace, help build consensus on critical issues, and strengthen our technology development program. Through international agreements EM engages in cooperative exchange of information, technology, and individuals. Currently, we are managing agreements with a dozen countries in Europe, Latin America, and Asia. These agreements focus on environmental restoration, waste management, transportation of radioactive wastes, and decontamination and decommissioning. This publication contains the following articles: in situ remediation integrated program; in-situ characterization and inspection of tanks; multimedia environmental pollutant assessment system (MEPAS); LLNL wet oxidation -- AEA technology. Besides these articles, this publication covers: EU activities with Russia; technology transfer activities; and international organization activities.

  20. The solution of linear systems of equations with a structural analysis code on the NAS CRAY-2

    NASA Technical Reports Server (NTRS)

    Poole, Eugene L.; Overman, Andrea L.

    1988-01-01

    Two methods for solving linear systems of equations on the NAS Cray-2 are described. One is a direct method; the other is an iterative method. Both methods exploit the architecture of the Cray-2, particularly the vectorization, and are aimed at structural analysis applications. To demonstrate and evaluate the methods, they were installed in a finite element structural analysis code denoted the Computational Structural Mechanics (CSM) Testbed. A description of the techniques used to integrate the two solvers into the Testbed is given. Storage schemes, memory requirements, operation counts, and reformatting procedures are discussed. Finally, results from the new methods are compared with results from the initial Testbed sparse Choleski equation solver for three structural analysis problems. The new direct solvers described achieve the highest computational rates of the methods compared. The new iterative methods are not able to achieve as high computation rates as the vectorized direct solvers but are best for well conditioned problems which require fewer iterations to converge to the solution.

  1. GaInNAs-based Hellish-vertical cavity semiconductor optical amplifier for 1.3 μm operation.

    PubMed

    Chaqmaqchee, Faten Adel Ismail; Mazzucato, Simone; Oduncuoglu, Murat; Balkan, Naci; Sun, Yun; Gunes, Mustafa; Hugues, Maxime; Hopkinson, Mark

    2011-01-01

    Hot electron light emission and lasing in semiconductor heterostructure (Hellish) devices are surface emitters the operation of which is based on the longitudinal injection of electrons and holes in the active region. These devices can be designed to be used as vertical cavity surface emitting laser or, as in this study, as a vertical cavity semiconductor optical amplifier (VCSOA). This study investigates the prospects for a Hellish VCSOA based on GaInNAs/GaAs material for operation in the 1.3-μm wavelength range. Hellish VCSOAs have increased functionality, and use undoped distributed Bragg reflectors; and this coupled with direct injection into the active region is expected to yield improvements in the gain and bandwidth. The design of the Hellish VCSOA is based on the transfer matrix method and the optical field distribution within the structure, where the determination of the position of quantum wells is crucial. A full assessment of Hellish VCSOAs has been performed in a device with eleven layers of Ga0.35In0.65N0.02As0.08/GaAs quantum wells (QWs) in the active region. It was characterised through I-V, L-V and by spectral photoluminescence, electroluminescence and electro-photoluminescence as a function of temperature and applied bias. Cavity resonance and gain peak curves have been calculated at different temperatures. Good agreement between experimental and theoretical results has been obtained. PMID:21711630

  2. GaInNAs-based Hellish-vertical cavity semiconductor optical amplifier for 1.3 μm operation

    PubMed Central

    2011-01-01

    Hot electron light emission and lasing in semiconductor heterostructure (Hellish) devices are surface emitters the operation of which is based on the longitudinal injection of electrons and holes in the active region. These devices can be designed to be used as vertical cavity surface emitting laser or, as in this study, as a vertical cavity semiconductor optical amplifier (VCSOA). This study investigates the prospects for a Hellish VCSOA based on GaInNAs/GaAs material for operation in the 1.3-μm wavelength range. Hellish VCSOAs have increased functionality, and use undoped distributed Bragg reflectors; and this coupled with direct injection into the active region is expected to yield improvements in the gain and bandwidth. The design of the Hellish VCSOA is based on the transfer matrix method and the optical field distribution within the structure, where the determination of the position of quantum wells is crucial. A full assessment of Hellish VCSOAs has been performed in a device with eleven layers of Ga0.35In0.65N0.02As0.08/GaAs quantum wells (QWs) in the active region. It was characterised through I-V, L-V and by spectral photoluminescence, electroluminescence and electro-photoluminescence as a function of temperature and applied bias. Cavity resonance and gain peak curves have been calculated at different temperatures. Good agreement between experimental and theoretical results has been obtained. PMID:21711630

  3. Optical transitions in GaNAs quantum wells with variable nitrogen content embedded in AlGaAs

    NASA Astrophysics Data System (ADS)

    Elborg, M.; Noda, T.; Mano, T.; Sakuma, Y.

    2016-06-01

    We investigate the optical transitions of GaNxAs1-x quantum wells (QWs) embedded in wider band gap AlGaAs. A combination of absorption and emission spectroscopic techniques is employed to systematically investigate the properties of GaNAs QWs with N concentrations ranging from 0 - 3%. From measurement of the photocurrent spectra, we find that besides QW ground state and first excited transition, distinct increases in photocurrent generation are observed. Their origin can be explained by N-induced modifications in the density of states at higher energies above the QW ground state. Photoluminescence experiments reveal that peak position dependence with temperature changes with N concentration. The characteristic S-shaped dependence for low N concentrations of 0.5% changes with increasing N concentration where the low temperature red-shift of the S-shape gradually disappears. This change indicates a gradual transition from impurity picture, where localized N induced energy states are present, to alloying picture, where an impurity-band is formed. In the highest-N sample, photoluminescence emission shows remarkable temperature stability. This phenomenon is explained by the interplay of N-induced energy states and QW confined states.

  4. Origin of radiative recombination and manifestations of localization effects in GaAs/GaNAs core/shell nanowires

    SciTech Connect

    Chen, S. L.; Filippov, S.; Chen, W. M.; Buyanova, I. A.; Ishikawa, Fumitaro

    2014-12-22

    Radiative carrier recombination processes in GaAs/GaNAs core/shell nanowires grown by molecular beam epitaxy on a Si substrate are systematically investigated by employing micro-photoluminescence (μ-PL) and μ-PL excitation (μ-PLE) measurements complemented by time-resolved PL spectroscopy. At low temperatures, alloy disorder is found to cause localization of photo-excited carriers leading to predominance of optical transitions from localized excitons (LE). Some of the local fluctuations in N composition are suggested to lead to strongly localized three-dimensional confining potential equivalent to that for quantum dots, based on the observation of sharp and discrete PL lines within the LE contour. The localization effects are found to have minor influence on PL spectra at room temperature due to thermal activation of the localized excitons to extended states. Under these conditions, photo-excited carrier lifetime is found to be governed by non-radiative recombination via surface states which is somewhat suppressed upon N incorporation.

  5. Utility experience with a 250-kW molten carbonate fuel cell cogeneration power plant at NAS Miramar, San Diego

    NASA Astrophysics Data System (ADS)

    Figueroa, R. A.; Otahal, J.

    This paper focuses on the strategy and experience of San Diego Gas and Electric with the development and demonstration of a proof of concept 250-kW internally manifolded heat exchanger (IMHEX®) carbonate fuel cell power plant. The plant was installed, commissioned, and operated by San Diego Gas and Electric (SDG&E) in a cogeneration mode at the Naval Air Station (NAS) at Miramar in San Diego. These activities were part of a collaborative effort between SDG&E and M-C Power's Program team (IMHEX® Team). The IMHEX® Team consists of M-C Power, Bechtel Engineering, Stewart and Stevenson, and the Institute of Gas Technology (IGT). The technical aspects of the plant's commissioning and operation were addressed by my colleague, J. Otahal, in a poster presentation. Our activities in carbonate fuel cell development are unique because of the level of involvement by an investor-owned utility in the development, engineering, installation, operation and maintenance of a fuel cell demonstration plant. The following topics are discussed in this paper: (i) SDG&E's involvement in the development of molten carbonate fuel cell (MCFC) technology; (ii) the active role in engineering and specification of the IMHEX® MCFC demonstration plant; (iii) responsibility for installation, commissioning, and operation; (iv) utility role in technology development and application of MCFC in a restructured and competitive environment; (v) summary.

  6. Mismatch discrimination of lipidated DNA and LNA-probes (LiNAs) in hybridization-controlled liposome assembly.

    PubMed

    Jakobsen, Ulla; Vogel, Stefan

    2016-08-01

    Assays for mismatch discrimination and detection of single nucleotide variations by hybridization-controlled assembly of liposomes, which do not require tedious surface chemistry, are versatile for both DNA and RNA targets. We report herein a comprehensive study on different DNA and LNA (locked nucleic acids) probe designs, including membrane-anchoring requirements, studies on different probes and target lengths (including overhangs), DNA and RNA targets (including sequences associated with pathogens) for lipidated nucleic acids (LiNAs). Advantages and limitations of the liposome assembly based assay in the context of mismatch discrimination and SNP detection are presented. The advantages of membrane-anchored LiNA-probes compared to chemically attached probes on solid nanoparticles (e.g. gold nanoparticles) are described. Key functionalities such as non-covalent attachment of LiNA probes without the need for long spacers and the inherent mobility of membrane-anchored probes in lipid-bilayer membranes will be described for several different probe designs. PMID:27356098

  7. Many factors complicate EM susceptibility tests

    NASA Astrophysics Data System (ADS)

    Richards, R. J.

    1982-09-01

    Procedures and apparatus currently employed for assaying the EM susceptibility of communication, navigation, and EW equipment are described. Susceptibility is examined in either conducted susceptibility tests, where signals are introduced into the input port of the device under test, or in radiated modes, where the entire device is exposed to an EM field to test for component and system failure. Noting that military standards require up to 10 times the EM resistance as commercial standards, the use of shielded enclosures in both commercial and military testing facilities is explored. RF-tight enclosures are filled with a homogeneous EM field produced by, optimally, broadband generators which emit signals which are amplified to desired levels. Sweep functions permit testing under broadband conditions. Attention is given to radiator selection and antenna choice to produce satisfactory test conditions at all frequencies.

  8. Unified Data Resource for CryoEM

    PubMed Central

    Lawson, Catherine L.

    2010-01-01

    3D cryo-electron microscopy reconstruction methods are uniquely able to reveal structures of many important macromolecules and macromolecular complexes. EMDataBank.org, a joint effort of the Protein Data Bank in Europe (PDBe), the Research Collaboratory for Structural Bioinformatics (RCSB), and the National Center for Macromolecular Imaging (NCMI), is a “one-stop shop” resource for global deposition and retrieval of cryoEM map, model and associated metadata. The resource unifies public access to the two major EM Structural Data archives: EM Data Bank (EMDB) and Protein Data Bank (PDB), and facilitates use of EM structural data of macromolecules and macromolecular complexes by the wider scientific community. PMID:20888470

  9. EMS in Taiwan: past, present, and future.

    PubMed

    Chiang, Wen-Chu; Ko, Patrick Chow-In; Wang, Hui-Chih; Yang, Chi-Wei; Shih, Fuh-Yuan; Hsiung, Kuang-Hua; Ma, Matthew Huei-Ming

    2009-01-01

    Taiwan is a small island country located in East Asia. From around 1995 modern concepts of the EMS were imported and supported by legislation. Considerable progress has since been made towards the construction of an effective pre-hospital care system. This article introduces the current status of the EMS in Taiwan, including the systems, response configurations, funding, personnel, medical directorship, and outcome research. The features and problems of in-hospital emergency care are also discussed. Key areas for further development in the country vary depending on regional differences in available resource and population density. An analysis of the strength, weakness, opportunity, and threats of the evolving EMS in Taiwan could be an example for other countries where the EMS is undergoing a similar process of development and optimisation. PMID:19059690

  10. A room temperature Na/S battery using a β″ alumina solid electrolyte separator, tetraethylene glycol dimethyl ether electrolyte, and a S/C composite cathode

    NASA Astrophysics Data System (ADS)

    Kim, Icpyo; Park, Jin-Young; Kim, Chang Hyeon; Park, Jin-Woo; Ahn, Jae-Pyoung; Ahn, Jou-Hyeon; Kim, Ki-Won; Ahn, Hyo-Jun

    2016-01-01

    To realize a high-performance room temperature Na/S battery with an elemental sulfur cathode, it is important that sodium polysulfides stay within the cathode and that they have room enough to react freely. In this work, sodium polysulfides are confined to the cathode using a β″ alumina solid electrolyte separator and an optimal amount of tetraethylene glycol dimethyl ether (TEGDME) electrolyte. In addition, an activated carbon material, in the form of a sulfur/carbon (S/C) composite, with high surface area, porosity, and pore volume is employed in the cathode. The resulting Na/S battery shows a high first discharge capacity of 855 mAh g-1 and coulombic efficiency close to 100%, as well as stable cyclability, with a discharge capacity of 521 mAh g-1 at the 104th discharge.

  11. Weather Requirements and Procedures for Step 1: High Altitude Long Endurance (HALE) Unmanned Aircraft System (UAS) Flight Operations in the National Air Space (NAS)

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This cover sheet is for version 2 of the weather requirements document along with Appendix A. The purpose of the requirements document was to identify and to list the weather functional requirements needed to achieve the Access 5 vision of "operating High Altitude, Long Endurance (HALE) Unmanned Aircraft Systems (UAS) routinely, safely, and reliably in the National Airspace System (NAS) for Step 1." A discussion of the Federal Aviation Administration (FAA) references and related policies, procedures, and standards is provided as basis for the recommendations supported within this document. Additional procedures and reference documentation related to weather functional requirements is also provided for background. The functional requirements and related information are to be proposed to the FAA and various standards organizations for consideration and approval. The appendix was designed to show that sources of flight weather information are readily available to UAS pilots conducting missions in the NAS. All weather information for this presentation was obtained from the public internet.

  12. MOVPE growth studies of Ga(NAsP)/(BGa)(AsP) multi quantum well heterostructures (MQWH) for the monolithic integration of laser structures on (001) Si-substrates

    NASA Astrophysics Data System (ADS)

    Ludewig, P.; Reinhard, S.; Jandieri, K.; Wegele, T.; Beyer, A.; Tapfer, L.; Volz, K.; Stolz, W.

    2016-03-01

    High-quality, pseudomorphically strained Ga(NAsP)/(BGa)(AsP)-multiple quantum well heterostructures (MQWH) have been deposited on exactly oriented (001) Si-substrate by metal organic vapour phase epitaxy (MOVPE) in a wide temperature range between 525 °C and 700 °C. The individual atomic incorporation efficiencies, growth rates as well as nanoscale material properties have been clarified by applying detailed high-resolution X-ray diffraction (HR-XRD), photoluminescence (PL) spectroscopy and high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) studies. An almost constant N-incorporation efficiency is obtained for a wide growth temperature range from 550 °C up to 650 °C. The P-incorporation is steadily increasing with increasing growth temperature reaching values at high temperatures in excess of the applied gas phase ratio. While the lower interface from the binary GaP- to the quaternary Ga(NAsP)-material system is very sharp, the upper interface is significantly rougher with a roughness scale of ±0.43 nm in quantum well thickness variation at a growth temperature of 525 °C. This roughness scale increases steadily with increasing growth temperature. No indication of any phase separation effects is detected in the Ga(NAsP)-material system even at the highest growth temperature of 700 °C. The obtained experimental results are briefly discussed with respect to the anticipated metastable character of the novel dilute-nitride Ga(NAsP)-material system grown lattice-matched to (001) Si-substrate.

  13. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project, UAS Control and Non-Payload Communication System Phase-1 Flight Test Results

    NASA Technical Reports Server (NTRS)

    Griner, James H.

    2014-01-01

    NASA's UAS Integration in the NAS project, has partnered with Rockwell Collins to develop a concept Control and Non-Payload Communication (CNPC) system prototype radio, operating on recently allocated UAS frequency spectrum bands. This prototype radio is being used to validate initial proposed performance requirements for UAS control communications. This presentation will give an overview of the current status of the prototype radio development, and results from phase 1 flight tests conducted during 2013.

  14. Molecular beam epitaxy of GaNAs alloys with high As content for potential photoanode applications in hydrogen production

    SciTech Connect

    Novikov, S. V.; Staddon, C. R.; Foxon, C. T.; Yu, K. M.; Broesler, R.; Hawkridge, M.; Liliental-Weber, Z.; Walukiewicz, W.; Denlinger, J.; Demchenko, I.

    2009-10-06

    The authors have succeeded in growing GaN1?xAsx alloys over a large composition range (0 < x < 0.8) by plasma-assisted molecular beam epitaxy. The enhanced incorporation of As was achieved by growing the films with high As{sub 2} flux at low (as low as 100 C) growth temperatures, which is much below the normal GaN growth temperature range. Using x-ray and transmission electron microscopy, they found that the GaNAs alloys with high As content x > 0.17 are amorphous. Optical absorption measurements together with x-ray absorption and emission spectroscopy results reveal a continuous gradual decrease in band gap from -3.4 to < 1 eV with increasing As content. The energy gap reaches its minimum of -0.8 eV at x - 0.8. The composition dependence of the band gap of the crystalline GaN{sub 1?x}As{sub x} alloys follows the prediction of the band anticrossing model (BAC). However, our measured band gap of amorphous GaN{sub 1?x}As{sub x} with 0.3 < x < 0.8 are larger than that predicted by BAC. The results seem to indicate that for this composition range the amorphous GaN{sub 1?x}As{sub x} alloys have short-range ordering that resembles random crystalline GaN{sub 1?x}As{sub x} alloys. They have demonstrated the possibility of the growth of amorphous GaN{sub 1?x}As{sub x} layers with variable As content on glass substrates

  15. Improved Performance of GaInNAs Solar Cells Grown by Molecular-Beam Epitaxy Using Increased Growth Rate Instead of Surfactants

    SciTech Connect

    Ptak, A. J.; France, R.; Jiang, C. S.; Romero, M. J.

    2009-01-01

    GaInNAs is potentially useful for increasing the conversion efficiency of multijunction solar cells if low photocurrents and photovoltages can be increased. Wide-depletion width devices generate significant photocurrents using an n-i-p structure grown by molecular-beam epitaxy, but these wide depletion widths are only realized in a region of parameter space that leads to rough surface morphologies. Surfactants are effective at reducing the surface roughness, but lead to increased defect densities and changes in the net acceptor or donor concentration. Here, we show that increasing the growth rate of GaInNAs solar cells leads to smooth surfaces without the use of a surfactant, even at high In compositions and substrate temperatures. No degradation in material quality is observed when increasing the growth rate from 1.5 to 3.0 {micro}m/h, but a shunt resistance does appear for the high-growth-rate samples. This shunt is attributed to increased spitting of the Ga cell, leading to an increase in the oval defect density, at the higher effusion cell temperatures used to achieve high growth rates. As with the case of Bi in GaInNAs, increased growth rates also appear to increase the net donor concentration, but it is not clear if these effects have the same cause.

  16. Inactivation of gltB Abolishes Expression of the Assimilatory Nitrate Reductase Gene (nasB) in Pseudomonas putida KT2442

    PubMed Central

    Eberl, Leo; Ammendola, Aldo; Rothballer, Michael H.; Givskov, Michael; Sternberg, Claus; Kilstrup, Mogens; Schleifer, Karl-Heinz; Molin, Søren

    2000-01-01

    By using mini-Tn5 transposon mutagenesis, random transcriptional fusions of promoterless bacterial luciferase, luxAB, to genes of Pseudomonas putida KT2442 were generated. Insertion mutants that responded to ammonium deficiency by induction of bioluminescence were selected. The mutant that responded most strongly was genetically analyzed and is demonstrated to bear the transposon within the assimilatory nitrate reductase gene (nasB) of P. putida KT2442. Genetic evidence as well as sequence analyses of the DNA regions flanking nasB suggest that the genes required for nitrate assimilation are not clustered. We isolated three second-site mutants in which induction of nasB expression was completely abolished under nitrogen-limiting conditions. Nucleotide sequence analysis of the chromosomal junctions revealed that in all three mutants the secondary transposon had inserted at different sites in the gltB gene of P. putida KT2442 encoding the major subunit of the glutamate synthase. A detailed physiological characterization of the gltB mutants revealed that they are unable to utilize a number of potential nitrogen sources, are defective in the ability to express nitrogen starvation proteins, display an aberrant cell morphology under nitrogen-limiting conditions, and are impaired in the capacity to survive prolonged nitrogen starvation periods. PMID:10852866

  17. Identification of nitrogen- and host-related deep-level traps in n-type GaNAs and their evolution upon annealing

    SciTech Connect

    Gelczuk, Ł.; Henini, M.

    2014-07-07

    Deep level traps in as-grown and annealed n-GaNAs layers (doped with Si) of various nitrogen concentrations (N=0.2%, 0.4%, 0.8%, and 1.2%) were investigated by deep level transient spectroscopy. In addition, optical properties of GaNAs layers were studied by photoluminescence and contactless electroreflectance. The identification of N- and host-related traps has been performed on the basis of band gap diagram [Kudrawiec, Appl. Phys. Lett. 101, 082109 (2012)], which assumes that the activation energy of electron traps of the same microscopic nature decreases with the rise of nitrogen concentration in accordance with the N-related shift of the conduction band towards trap levels. The application of this diagram has allowed to investigate the evolution of donor traps in GaNAs upon annealing. In general, it was observed that the concentration of N- and host-related traps decreases after annealing and PL improves very significantly. However, it was also observed that some traps are generated due to annealing. It explains why the annealing conditions have to be carefully optimized for this material system.

  18. Designing of 1 eV GaNAs/GaInAs superlattice subcell in current-matched four-junction solar cell

    NASA Astrophysics Data System (ADS)

    Haixiao, Wang; Xinhe, Zheng; Xingyuan, Gan; Naiming, Wang; Hui, Yang

    2016-01-01

    A reasonably-thick GaNAs/GaInAs superlattice could be an option as a roughly 1 eV subcell to achieve high-efficiency multi-junction solar cells on a lattice-matched Ge substrate. A detailed consideration of a high-efficiency design for a GaInP/GaAs/1 eV/Ge device is presented. Calculations have been done for this structure to obtain the confined energies of the electrons and holes by utilizing the Kronig-Penney model, as well as the absorption coefficient and thereby the external quantum efficiency. The effect of well layers, GaNAs or GaInAs, on the absorption and photocurrent density under the AM 1.5 condition is discussed in order to realize a requirement of current matching in the four-junction solar cells. The management of these considerations implies the feasibility of the GaNAs/GaInAs superlattice subcell design to improve the overall conversion efficiency of lattice matched GaInP/GaAs/1 eV/Ge cells. Project supported by the National Natural Science Foundation of China (No. 61274134) and the International Cooperation Program of Suzhou, China (No. SH201215).

  19. The NAS parallel benchmarks

    NASA Technical Reports Server (NTRS)

    Bailey, David (Editor); Barton, John (Editor); Lasinski, Thomas (Editor); Simon, Horst (Editor)

    1993-01-01

    A new set of benchmarks was developed for the performance evaluation of highly parallel supercomputers. These benchmarks consist of a set of kernels, the 'Parallel Kernels,' and a simulated application benchmark. Together they mimic the computation and data movement characteristics of large scale computational fluid dynamics (CFD) applications. The principal distinguishing feature of these benchmarks is their 'pencil and paper' specification - all details of these benchmarks are specified only algorithmically. In this way many of the difficulties associated with conventional benchmarking approaches on highly parallel systems are avoided.

  20. Development and manufacturing of panoramic Stokes polarimeter using the polarization films in the Main Astronomical Observatory of NAS of Ukraine

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.; Ivanov, Yu. S.; Syniavskyi, I. I.; Sergeev, A. V.

    2015-08-01

    In the Main Astronomical Observatory of NAS of Ukraine is proposed and implemented the concept of the imaging Stokes polarimeter [1-5]. This device allows carrying out measurements of the four Stokes vector components at the same time, in a wide field, and without any restrictions on the relative aperture of the optical system. Its scheme is developed so that only by turning wheel with replaceable elements, photopolarimeter could be transformed into a low resolution spectropolarimeter. The device has four film's polarizers with positional angles 0°, 45°, 90°, 135°. The device uses a system of special deflecting prisms in each channel. These prisms were achromatizing in the spectral range of 420-850 nm [2], the distortion of the polarimeter optical system is less than 0.65%. In manufacturing version of spectropolarimeter provided for the possibility of using working on passing the diffraction grating with a frequency up to 100 lines/mm. Has begun the laboratory testing of instrument. References. 1. Sinyavskii I.I., Ivanov Yu. S., Vidmachenko Anatoliy P., Karpov N.V. Panoramic Stokes-polarimeter // Ecological bulettin of research centers of the Black Sea Economic Cooperation. - 2013. - V. 3, No 4. - P. 123-127. 2. Sinyavskii I. I., Ivanov Yu. S., Vil'machenko A. P. Concept of the construction, of the optical setup of a panoramic Stokes polarimeter for small telescopes // Journal of Optical Technology. - 2013. - V. 80, Issue 9. - P. 545-548. 3. Vidmachenko A. P., Ivanov Yu. S., Morozhenko A. V., Nevodovsky E. P., Syniavskyi I. I., Sosonkin M. G. Spectropolarimeter of ground-based accompanying for the space experiment "Planetary Monitoring" // Kosmichna Nauka i Tekhnologiya. - 2007. - V. 13, No. 1, p. 63 - 70. 4. Yatskiv Ya. S., Vidmachenko A. P., Morozhenko A. V., Sosonkin M. G., Ivanov Yu. S., Syniavskyi I. I. Spectropolarimetric device for overatmospheric investigations of Solar System bodies // Kosmichna Nauka i Tekhnologiya. - 2008. - V. 14, No. 2. - P. 56

  1. EMS adaptation for climate change

    NASA Astrophysics Data System (ADS)

    Pan, C.; Chang, Y.; Wen, J.; Tsai, M.

    2010-12-01

    The purpose of this study was to find an appropriate scenario of pre-hospital transportation of an emergency medical service (EMS) system for burdensome casualties resulting from extreme climate events. A case of natural catastrophic events in Taiwan, 88 wind-caused disasters, was reviewed and analyzed. A sequential-conveyance method was designed to shorten the casualty transportation time and to promote the efficiency of ambulance services. A proposed mobile emergency medical center was first constructed in a safe area, but nearby the disaster area. The Center consists of professional medical personnel who process the triage of incoming patients and take care of casualties with minor injuries. Ambulances in the Center were ready to sequentially convey the casualties with severer conditions to an assigned hospital that is distant from the disaster area for further treatment. The study suggests that if we could construct a spacious and well-equipped mobile emergency medical center, only a small portion of casualties would need to be transferred to distant hospitals. This would reduce the over-crowding problem in hospital ERs. First-line ambulances only reciprocated between the mobile emergency medical center and the disaster area, saving time and shortening the working distances. Second-line ambulances were highly regulated between the mobile emergency medical center and requested hospitals. The ambulance service of the sequential-conveyance method was found to be more efficient than the conventional method and was concluded to be more profitable and reasonable on paper in adapting to climate change. Therefore, additional practical work should be launched to collect more precise quantitative data.

  2. 10 CFR Appendixes E-M to Part 52 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false E Appendixes E-M to Part 52 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Appendixes E-M to Part 52...

  3. 10 CFR Appendixes E-M to Part 52 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false E Appendixes E-M to Part 52 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Appendixes E-M to Part 52...

  4. 10 CFR Appendixes E-M to Part 52 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 2 2012-01-01 2012-01-01 false E Appendixes E-M to Part 52 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Appendixes E-M to Part 52...

  5. 10 CFR Appendixes E-M to Part 52 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false E Appendixes E-M to Part 52 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Appendixes E-M to Part 52...

  6. 10 CFR Appendixes E-M to Part 52 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false E Appendixes E-M to Part 52 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES, CERTIFICATIONS, AND APPROVALS FOR NUCLEAR POWER PLANTS Appendixes E-M to Part 52...

  7. Processing of Cryo-EM Movie Data.

    PubMed

    Ripstein, Z A; Rubinstein, J L

    2016-01-01

    Direct detector device (DDD) cameras dramatically enhance the capabilities of electron cryomicroscopy (cryo-EM) due to their improved detective quantum efficiency (DQE) relative to other detectors. DDDs use semiconductor technology that allows micrographs to be recorded as movies rather than integrated individual exposures. Movies from DDDs improve cryo-EM in another, more surprising, way. DDD movies revealed beam-induced specimen movement as a major source of image degradation and provide a way to partially correct the problem by aligning frames or regions of frames to account for this specimen movement. In this chapter, we use a self-consistent mathematical notation to explain, compare, and contrast several of the most popular existing algorithms for computationally correcting specimen movement in DDD movies. We conclude by discussing future developments in algorithms for processing DDD movies that would extend the capabilities of cryo-EM even further. PMID:27572725

  8. Risk Communication Within the EM Program

    SciTech Connect

    Edelson, M.

    2003-02-26

    The U.S. Department of Energy Environmental Management program (EM) conducts the most extensive environmental remediation effort in the world. The annual EM budgets have exceeded $6,000,000,000 for approximately ten years and EM has assumed responsibility for the cleanup of the largest DOE reservations (i.e., at Hanford, Washington, Aiken, South Carolina, and Idaho Falls, Idaho) as well as the facilities at Rocky Flats, Colorado and in Ohio. Each of these sites has areas of extensive radioactive and chemical contamination, numerous surplus facilities that require decontamination and removal, while some have special nuclear material that requires secure storage. The EM program has been criticized for being ineffective (1) and has been repeatedly reorganized to address perceived shortcomings. The most recent reorganization was announced in 2001 to become effective at the beginning of the 2003 Federal Fiscal Year (i.e., October 2002). It was preceded by a ''top to bottom'' review (TTBR) of the program (2) that identified several deficiencies that were to be corrected as a result of the reorganization. One prominent outcome of the TTBR was the identification of ''risk reduction'' as an organizing principle to prioritize the activities of the new EM program. The new program also sought to accelerate progress by identifying a set of critical activities at each site that could be accelerated and result in more rapid site closure, with attendant risk, cost, and schedule benefits. This paper investigates how the new emphasis on risk reduction in the EM program has been communicated to EM stakeholders and regulators. It focuses on the Rocky Flats Environmental Technology Site (RFETS) as a case study and finds that there is little evidence for a new emphasis on risk reduction in EM communications with RFETS stakeholders. Discussions between DOE and RFETS stakeholders often refer to ''risk,'' but the word serves as a placeholder for other concepts. Thus ''risk'' communication

  9. Molecular beam epitaxy growth of 1.55 μm GaInNAs(Sb) double quantum wells with bright and narrow photoluminescence

    NASA Astrophysics Data System (ADS)

    Gupta, J. A.; Sproule, G. I.; Wu, X.; Wasilewski, Z. R.

    2006-05-01

    GaInNAs(Sb)/GaNAs double quantum well (DQW) structures were grown on GaAs substrates using solid-source molecular beam epitaxy with N 2/Ar gas mixtures in a radio frequency plasma cell. A novel method of in situ antimony mass spectrometry is introduced which permits flux monitoring in the presence of large arsenic background pressures. For a DQW sample grown without Sb, bright and narrow (38.1 meV) room temperature photoluminescence (PL) emission at 1509 nm was achieved after optimized rapid thermal annealing. In two samples grown with antimony fluxes of approximately 0.012 and 0.028 monolayers/s the PL intensity improved and very bright PL was observed at 1518 and 1551 nm with linewidths of 33.1 and 35.0 meV, respectively. The integrated PL intensities of each of these two samples was equivalent to the emission for a reference GaInNAs/GaAs DQW sample emitting closer to 1.3 μm. More strikingly, the intensity of the Sb-free 1509 nm sample was only lower by a factor of 2. This suggests that the N 2/Ar plasma approach has benefits for the material quality, as well as providing efficient flux control, yielding good material even without Sb. High-resolution X-ray diffraction and transmission electron microscopy measurements indicate excellent crystal quality for all samples. Secondary ion mass spectrometry reveals a dramatic tendency for Sb segregation during growth, resulting in very asymmetric incorporation with most of the Sb atoms located at the top interface.

  10. NOD promoter-controlled AtIRT1 expression functions synergistically with NAS and FERRITIN genes to increase iron in rice grains.

    PubMed

    Boonyaves, Kulaporn; Gruissem, Wilhelm; Bhullar, Navreet K

    2016-02-01

    Rice is a staple food for over half of the world's population, but it contains only low amounts of bioavailable micronutrients for human nutrition. Consequently, micronutrient deficiency is a widespread health problem among people who depend primarily on rice as their staple food. Iron deficiency anemia is one of the most serious forms of malnutrition. Biofortification of rice grains for increased iron content is an effective strategy to reduce iron deficiency. Unlike other grass species, rice takes up iron as Fe(II) via the IRON REGULATED TRANSPORTER (IRT) in addition to Fe(III)-phytosiderophore chelates. We expressed Arabidopsis IRT1 (AtIRT1) under control of the Medicago sativa EARLY NODULIN 12B promoter in our previously developed high-iron NFP rice lines expressing NICOTIANAMINE SYNTHASE (AtNAS1) and FERRITIN. Transgenic rice lines expressing AtIRT1 alone had significant increases in iron and combined with NAS and FERRITIN increased iron to 9.6 µg/g DW in the polished grains that is 2.2-fold higher as compared to NFP lines. The grains of AtIRT1 lines also accumulated more copper and zinc but not manganese. Our results demonstrate that the concerted expression of AtIRT1, AtNAS1 and PvFERRITIN synergistically increases iron in both polished and unpolished rice grains. AtIRT1 is therefore a valuable transporter for iron biofortification programs when used in combination with other genes encoding iron transporters and/or storage proteins. PMID:26560141

  11. Low-loss 1.3-microm GaInNAs saturable Bragg reflector for high-power picosecond neodymium lasers.

    PubMed

    Sun, H D; Valentine, G J; Macaluso, R; Calvez, S; Burns, D; Dawson, M D; Jouhti, T; Pessa, M

    2002-12-01

    A novel low-loss, single-step-growth 1.3-microm GaInNAs saturable Bragg reflector mode-locking element has been developed. Combined radial thickness and postgrowth annealing control have permitted a tuning range of 46 nm for passive mode locking to be demonstrated from one wafer. With this structure, stabilized mode locking was obtained from quasi-cw diode-pumped Nd:YLF and Nd:YALO lasers operating at 1314 and 1342 nm, respectively, with average on-time output powers of as much as 20 W and pulse durations as low as 22 ps. PMID:18033462

  12. Do earthquakes generate EM signals?

    NASA Astrophysics Data System (ADS)

    Walter, Christina; Onacha, Stephen; Malin, Peter; Shalev, Eylon; Lucas, Alan

    2010-05-01

    study areas, large swarms of earthquakes were located very close to the electromagnetic coils. This abstract focuses on the data from the Wairakei area. Preliminary data analysis has been carried out by band pass filtering and removing of the harmonics of the 50 Hz power line frequency. The initial results clearly show that electromagnetic signals accompany the seismic P and S waves (coseismic signal). Further data analysis involves the extraction of the seismoelectric signal generated at the onset of the earthquake and at interfaces from the coseismic signal and other ‘noise' sources. This processing step exhibits a major challenge in seismoelectric data processing. Unlike in other studies we measured the EM field and the seismic field at one location. Therefore the seismoelectric wave travelling at the speed of light cannot be determined as easily in the arrival times as when an array of coils is used. This makes the determination of the origin time much more difficult. Hence other processing techniques need to be explored.

  13. A model for the bandgap energy of the dilute nitride InGaNAs alloys by modifying simplified coherent potential approximation

    NASA Astrophysics Data System (ADS)

    Zhao, Chuan-Zhen; Qu, You-Yang; Wei, Tong; Sun, Xiao-Dong; Wang, Sha-Sha; Lu, Ke-Qing

    2014-03-01

    In this paper, a model describing the bandgap energy of the dilute nitride alloy InxGa1-xNyAs1-y is developed based on the modification of simplified coherent potential approximation (MSCPA) and the band anti-crossing model (BAC). The parameters in the model are obtained by fitting the experimental bandgap energies of the ternary alloys InGaAs, InGaN, GaNAs and InNAs. It is found that the results agree well with the experimental data. We also find that although the bandgap energies of InxGa1-xNyAs1-y and InxGa1-xAs can be calculated by using MSCPA, the physical mechanisms for the bandgap evolution of InxGa1-xNyAs1-y and InxGa1-xAs are very different. In addition, it is found that the model in this work may be used in a larger composition range than the BAC model.

  14. Band structure and the optical gain of GaInNAs/GaAs quantum wells modeled within 10-band and 8-band kp model

    NASA Astrophysics Data System (ADS)

    Gladysiewicz, M.; Kudrawiec, R.; Miloszewski, J. M.; Weetman, P.; Misiewicz, J.; Wartak, M. S.

    2013-02-01

    The band structure and optical gain have been calculated for GaInNAs/GaAs quantum wells (QWs) with various nitrogen concentrations within the 10-band and 8-band kp models. Two approaches to calculate optical properties of GaInNAs/GaAs QWs have been compared and discussed in the context of available material parameters for dilute nitrides and the conduction band nonparabolicity due to the band anti-crossing (BAC) interaction between the N-related resonant level and the conduction band of a host material. It has been clearly shown that this nonparabolicity can be neglected in optical gain calculations since the dispersion of conduction band up to the Femi level is very close to parabolic for carrier concentrations typical for laser operation, i.e., 5 × 1018 cm-3. This means that the 8-band kp model when used to calculate the optical gain is very realistic and much easier to apply in QWs containing new dilute nitrides for which the BAC parameters are unknown. In such an approach, the energy gap and electron effective mass for N-containing materials are needed, instead of BAC parameters. These parameters are available experimentally much easier than BAC parameters.

  15. High gain 1.3-μm GaInNAs SOA with fast gain dynamics and enhanced temperature stability

    NASA Astrophysics Data System (ADS)

    Fitsios, D.; Giannoulis, G.; Iliadis, N.; Korpijärvi, V.-M.; Viheriälä, J.; Laakso, A.; Dris, S.; Spyropoulou, M.; Avramopoulos, H.; Kanellos, G. T.; Pleros, N.; Guina, M.

    2014-03-01

    Semiconductor optical amplifiers (SOAs) are a well-established solution of optical access networks. They could prove an enabling technology for DataCom by offering extended range of active optical functionalities. However, in such costand energy-critical applications, high-integration densities increase the operational temperatures and require powerhungry external cooling. Taking a step further towards improving the cost and energy effectiveness of active optical components, we report on the development of a GaInNAs/GaAs (dilute nitride) SOA operating at 1.3μm that exhibits a gain value of 28 dB and combined with excellent temperature stability owing to the large conduction band offset between GaInNAs quantum well and GaAs barrier. Moreover, the characterization results reveal almost no gain variation around the 1320 nm region for a temperature range from 20° to 50° C. The gain recovery time attained values as short as 100 ps, allowing implementation of various signal processing functionalities at 10 Gb/s. The combined parameters are very attractive for application in photonic integrated circuits requiring uncooled operation and thus minimizing power consumption. Moreover, as a result of the insensitivity to heating issues, a higher number of active elements can be integrated on chip-scale circuitry, allowing for higher integration densities and more complex optical on-chip functions. Such component could prove essential for next generation DataCom networks.

  16. p- to n-type conductivity transition in 1.0 eV GaInNAs solar cells controlled by the V/III ratio

    SciTech Connect

    Langer, Fabian Perl, Svenja; Kamp, Martin; Höfling, Sven

    2015-02-09

    In this work, we report a p- to n-type conductivity transition of GaInNAs (1.0 eV bandgap) layers in p-i-n dilute nitride solar cells continuously controlled by the V/III ratio during growth. Near the transition region, we were able to produce GaInNAs layers with very low effective electrically active doping concentrations resulting in wide depleted areas. We obtained internal quantum efficiencies (IQEs) up to 85% at 0.2 eV above the bandgap. However, the high IQE comes along with an increased dark current density resulting in a decreased open circuit voltage of about 0.2 V. This indicates the formation of non-radiant defect centers related to the p-type to n-type transition. Rapid-thermal annealing of the solar cells on the one hand helps to anneal some of these defects but on the other hand increases the effective doping concentrations.

  17. p- to n-type conductivity transition in 1.0 eV GaInNAs solar cells controlled by the V/III ratio

    NASA Astrophysics Data System (ADS)

    Langer, Fabian; Perl, Svenja; Höfling, Sven; Kamp, Martin

    2015-02-01

    In this work, we report a p- to n-type conductivity transition of GaInNAs (1.0 eV bandgap) layers in p-i-n dilute nitride solar cells continuously controlled by the V/III ratio during growth. Near the transition region, we were able to produce GaInNAs layers with very low effective electrically active doping concentrations resulting in wide depleted areas. We obtained internal quantum efficiencies (IQEs) up to 85% at 0.2 eV above the bandgap. However, the high IQE comes along with an increased dark current density resulting in a decreased open circuit voltage of about 0.2 V. This indicates the formation of non-radiant defect centers related to the p-type to n-type transition. Rapid-thermal annealing of the solar cells on the one hand helps to anneal some of these defects but on the other hand increases the effective doping concentrations.

  18. Model of hopping excitons in GaInNAs: simulations of sharp lines in micro-photoluminescence spectra and their dependence on the excitation power and temperature.

    PubMed

    Baranowski, M; Latkowska, M; Kudrawiec, R; Misiewicz, J

    2011-05-25

    The model of hopping excitons in semiconductors proposed by Baranovskii et al (1998 Phys. Rev. B 58 13081) has been modified and applied to explain sharp lines observed in micro-photoluminescence (μ-PL) spectra of GaInNAs alloys and their changes with excitation power and temperature. Instead of two types of recombination centres (radiative and nonradiative centres) introduced by Baranovskii et alwe have proposed one kind of localization centre with radiative and nonradiative rates. Such a modification is justifiable due to our recent experimental observations for GaInNAs alloys and allows us to explain the fast thermal quenching of localized emission from this alloy. Our simulations clearly show that the individual sharp PL lines observed at low temperatures appear for this material due to exciton hopping between localization centres. Taking into account saturation effects and the exciton dissociation phenomenon, it has been shown that the observed changes in power- and temperature dependent μ-PL spectra can be excellently reproduced by the modified model. PMID:21540495

  19. Experiências internacionais da aplicação de sistemas de apoio à decisão clínica em gastroenterologia

    PubMed Central

    Tenório, Josceli Maria; Hummel, Anderson Diniz; Sdepanian, Vera Lucia; Pisa, Ivan Torres; de Fátima Marin, Heimar

    2015-01-01

    Objetivo Descrever as experiências recentes com a aplicação de sistemas de apoio à decisão clínica em gastroenterologia, de forma a estabelecer o nível de desenvolvimento, testes e vantagens conferidas à prática médica com a introdução desses softwares. Métodos Foi realizada busca nas bases de dados PubMed, LILACS e ISI Web of Knowledge, utilizando termos relacionados à sistemas de apoio à decisão e à gastroenterogia, incluindo artigos originais publicados no período entre 2005 e 2010. Foram recuperadas 104 publicações, na busca inicial e, após a aplicação dos critérios de inclusão e exclusão, foram eleitos nove estudos para leitura do texto completo. Resultados Os sistemas de apoio à decisão clínica apresentam grande multiplicidade de problemas clínicos e investigação de doenças. Em 89% dos casos, são descritos modelos experimentais para o desenvolvimento de sistemas de apoio à decisão clínica. A descrição dos resultados obtidos por técnicas de inteligência artificial em 78% das publicações. Em dois dos estudos foram realizadas comparações com o médico e em apenas uma publicação um estudo controlado foi descrito, mostrando evidências de melhorias na prática médica. Conclusão Os estudos mostram potenciais benefícios dos sistemas de apoio à decisão clínica à prática médica, porém, estudos controlados em ambiente real devem ser realizados para comprovar esta perspectiva. PMID:26491625

  20. Projeto educação em ciências com observatórios virtuais: a participação da Escola Moppe no período 2000-2003

    NASA Astrophysics Data System (ADS)

    Wuensche, C. A.; Gavioli, E.; Oliveira, A. L. P. R. S.; da Silva, C.; Cardoso, H. P.; Estácio, S.

    2003-08-01

    O projeto Educação em Ciências com Observatórios Virtuais foi concebido pelo Instituto Astronômico e Geofísico da USP, agregando diversas instituições de ensino e pesquisa no país para desenvolver competências diversas na educação fundamental, média e superior utilizando a astronomia como ferramenta multidisciplinar. Este trabalho descreve a participação da MOPPE, escola-piloto do INPE no projeto, no período de 2000-2003. Serão apresentadas 1) a criação de um clube de ciências (1999 a 2001) cujo tema foi a colonização de Marte e 2) a ementa de astronomia trabalhada com as 7a. e 8a. séries do ensino fundamental. A proposta do projeto Colonizando Marte foi estudar diversos aspectos de uma missão interplanetária e construir experiementos que permitissem quantificar esses aspectos. Os resultados obtidos incluiram apresentações nas SBPC Jovem em 2000 e 2001. Discutiremos também as ementas de astronomia trabalhadas desde 2001 e o envolvimento dos alunos com atividades ligadas a astronomia, fora da aula de ciências. A inclusão de astronomia no currículo das últimas séries motivou a participação de mais alunos culminando com a conquista de duas medalhas para alunos da 7a. série na Olimpiada Brasileira de Astronomia em 2002. Houve também um aumento no número de participantes na OBA 2003 e nos projetos de astronomia mais elaborados nas Feira de Ciências de 2001 e 2002. Destacamos em 2003 a inclusão da MOPPE no projeto TIE - Telescopes in Education - da NASA, que utiliza o telescópio do Observatório de Mount Wilson (EUA) para observações remotas em projetos pedagógicos para o ensino de astronomia.

  1. The E-MS Algorithm: Model Selection with Incomplete Data

    PubMed Central

    Jiang, Jiming; Nguyen, Thuan; Rao, J. Sunil

    2014-01-01

    We propose a procedure associated with the idea of the E-M algorithm for model selection in the presence of missing data. The idea extends the concept of parameters to include both the model and the parameters under the model, and thus allows the model to be part of the E-M iterations. We develop the procedure, known as the E-MS algorithm, under the assumption that the class of candidate models is finite. Some special cases of the procedure are considered, including E-MS with the generalized information criteria (GIC), and E-MS with the adaptive fence (AF; Jiang et al. 2008). We prove numerical convergence of the E-MS algorithm as well as consistency in model selection of the limiting model of the E-MS convergence, for E-MS with GIC and E-MS with AF. We study the impact on model selection of different missing data mechanisms. Furthermore, we carry out extensive simulation studies on the finite-sample performance of the E-MS with comparisons to other procedures. The methodology is also illustrated on a real data analysis involving QTL mapping for an agricultural study on barley grains. PMID:26783375

  2. Ventos em supergigantes B[e] das nuvens de Magalhães e da Galáxia

    NASA Astrophysics Data System (ADS)

    de Araújo, F. X.; Pilling, D. A.; Pereira, C. B.; Fernandes, M. B.

    2003-08-01

    As Supergigantes B[e] apresentam as seguintes características: (i) alta luminosidade; (ii) espectro típico de estrelas de tipo B; (iii) linhas permitidas e proibidas em emissão de metais de baixa ionização, especialmente FeII; (iv) linhas de Balmer, e por vêzes também dos ions HeI e FeII, com perfis tipo P Cygni indicativos de altas taxas de perda de massa. Atualmente estamos desenvolvendo um projeto que visa comparar as propriedades fisicas (principalmente e v¥) dos ventos destes objetos nas Nuvens de Magalhães e na Galaxia. O objetivo é estudar a influência da metalicidade. No presente painel apresentamos uma determinação das velocidades terminais de 11 estrelas, sendo 4 na GNM (Hen S111, 66, R126 e Hen S93), 4 na PNM (Hen S18, S23, S65 e R4) e 3 na Galaxia (CPD-529243, MWC 300 e GG Car). Nossos dados são espectros de alta resolução obtidos no telescópio 1.52m do ESO com o espectrógrafo FEROS. Para determinar as velocidades terminais usamos as linhas Hd e HeI 3888 Å cujas componentes em absorção costumam estar livres de "blends" e estruturas. Nossos resultados sugerem que as velocidades de expansão na GNM são maiores (ainda que apenas ligeiramente) do que aquelas da PNM, como esperado. No entanto, os objetos da Galaxia não parecem seguir a mesma tendência.

  3. Percutaneous absorption and disposition of Tinopal EMS.

    PubMed

    Black, J G; Moule, R C; Philp, J

    1977-08-01

    A cotton-substantive, anionic, fluorescent whitening agent manufactured by several suppliers under various trade names e.g. Tinopal EMS, has been synthesized in radioactive form. Intubation of detergent or aqueous solution into rats resulted in little absorption from the intestinal tract as evidenced by low radioactivity in the urine and tissues. Most of the dose was excreted rapidly in the faeces. After parenteral administration to rats, the radioactivity was rapidly excreted in the faeces with small amounts remaining in tissues and organs. There was slight evidence of retention of radioactivity in the kidneys. Very small amounts of Tinopal EMS in detergent were absorbed through rat skin, but only when concentrations greater than those normally used by the consumer, together with occlusion of the skin were employed. Small amounts were absorbed throught skin when applied in ethanol. It is concluded that the possibility of systemic toxic effects in man as a result of percutaneous absorption is remote. PMID:929616

  4. Crosshole EM in steel-cased boreholes

    SciTech Connect

    Wilt, M.; Lee, K.H.; Becker, A.; Spies, B.; Wang, B.

    1996-07-01

    The application of crosshole EM methods through steel well-casing was investigated in theoretical, laboratory and field studies. A numerical code was developed that calculates the attenuation and phase delay of an EM dipole signal propagated through a steel well casing lodged in a homogeneous medium. The code was validated with a scale model and used for sensitivity studies of casing and formation properties. Finally, field measurements were made in an oil field undergoing waterflooding. Our most important findings are that (1) crosshole surveys are feasible using a well pair with one metallic and one non-metallic casing. (2) The casing effect seems be localized within the pipe section that includes the sensor. (3) The effects of the casing can be corrected using simple means and (4) crosshole field data that are sensitive to both formation and casing were acquired in a working environment.

  5. TandEM: Titan and Enceladus mission

    USGS Publications Warehouse

    Coustenis, A.; Atreya, S.K.; Balint, T.; Brown, R.H.; Dougherty, M.K.; Ferri, F.; Fulchignoni, M.; Gautier, D.; Gowen, R.A.; Griffith, C.A.; Gurvits, L.I.; Jaumann, R.; Langevin, Y.; Leese, M.R.; Lunine, J.I.; McKay, C.P.; Moussas, X.; Muller-Wodarg, I.; Neubauer, F.; Owen, T.C.; Raulin, F.; Sittler, E.C.; Sohl, F.; Sotin, C.; Tobie, G.; Tokano, T.; Turtle, E.P.; Wahlund, J.-E.; Waite, J.H.; Baines, K.H.; Blamont, J.; Coates, A.J.; Dandouras, I.; Krimigis, T.; Lellouch, E.; Lorenz, R.D.; Morse, A.; Porco, C.C.; Hirtzig, M.; Saur, J.; Spilker, T.; Zarnecki, J.C.; Choi, E.; Achilleos, N.; Amils, R.; Annan, P.; Atkinson, D.H.; Benilan, Y.; Bertucci, C.; Bezard, B.; Bjoraker, G.L.; Blanc, M.; Boireau, L.; Bouman, J.; Cabane, M.; Capria, M.T.; Chassefiere, E.; Coll, P.; Combes, M.; Cooper, J.F.; Coradini, A.; Crary, F.; Cravens, T.; Daglis, I.A.; de Angelis, E.; De Bergh, C.; de Pater, I.; Dunford, C.; Durry, G.; Dutuit, O.; Fairbrother, D.; Flasar, F.M.; Fortes, A.D.; Frampton, R.; Fujimoto, M.; Galand, M.; Grasset, O.; Grott, M.; Haltigin, T.; Herique, A.; Hersant, F.; Hussmann, H.; Ip, W.; Johnson, R.; Kallio, E.; Kempf, S.; Knapmeyer, M.; Kofman, W.; Koop, R.; Kostiuk, T.; Krupp, N.; Kuppers, M.; Lammer, H.; Lara, L.-M.; Lavvas, P.; Le, Mouelic S.; Lebonnois, S.; Ledvina, S.; Li, J.; Livengood, T.A.; Lopes, R.M.; Lopez-Moreno, J. -J.; Luz, D.; Mahaffy, P.R.; Mall, U.; Martinez-Frias, J.; Marty, B.; McCord, T.; Salvan, C.M.; Milillo, A.; Mitchell, D.G.; Modolo, R.; Mousis, O.; Nakamura, M.; Neish, C.D.; Nixon, C.A.; Mvondo, D.N.; Orton, G.; Paetzold, M.; Pitman, J.; Pogrebenko, S.; Pollard, W.; Prieto-Ballesteros, O.; Rannou, P.; Reh, K.; Richter, L.; Robb, F.T.; Rodrigo, R.; Rodriguez, S.; Romani, P.; Bermejo, M.R.; Sarris, E.T.; Schenk, P.; Schmitt, B.; Schmitz, N.; Schulze-Makuch, D.; Schwingenschuh, K.; Selig, A.; Sicardy, B.; Soderblom, L.; Spilker, L.J.; Stam, D.; Steele, A.; Stephan, K.; Strobel, D.F.; Szego, K.; Szopa

    2009-01-01

    TandEM was proposed as an L-class (large) mission in response to ESA's Cosmic Vision 2015-2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini-Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini-Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (Montgolfi??re) and possibly several landing probes to be delivered through the atmosphere. ?? Springer Science + Business Media B.V. 2008.

  6. Helicopter EMS: Research Endpoints and Potential Benefits

    PubMed Central

    Thomas, Stephen H.; Arthur, Annette O.

    2012-01-01

    Patients, EMS systems, and healthcare regions benefit from Helicopter EMS (HEMS) utilization. This article discusses these benefits in terms of specific endpoints utilized in research projects. The endpoint of interest, be it primary, secondary, or surrogate, is important to understand in the deployment of HEMS resources or in planning further HEMS outcomes research. The most important outcomes are those which show potential benefits to the patients, such as functional survival, pain relief, and earlier ALS care. Case reports are also important “outcomes” publications. The benefits of HEMS in the rural setting is the ability to provide timely access to Level I or Level II trauma centers and in nontrauma, interfacility transport of cardiac, stroke, and even sepsis patients. Many HEMS crews have pharmacologic and procedural capabilities that bring a different level of care to a trauma scene or small referring hospital, especially in the rural setting. Regional healthcare and EMS system's benefit from HEMS by their capability to extend the advanced level of care throughout a region, provide a “backup” for areas with limited ALS coverage, minimize transport times, make available direct transport to specialized centers, and offer flexibility of transport in overloaded hospital systems. PMID:22203905

  7. GaAs/AlGaAs resonant tunneling diodes with a GaInNAs absorption layer for telecommunication light sensing

    NASA Astrophysics Data System (ADS)

    Hartmann, F.; Langer, F.; Bisping, D.; Musterer, A.; Höfling, S.; Kamp, M.; Forchel, A.; Worschech, L.

    2012-04-01

    Al0.6Ga0.4As/GaAs/Al0.6Ga0.4As double-barrier resonant-tunneling diodes (RTD) were grown by molecular beam epitaxy with a nearby, lattice-matched Ga0.89In0.11N0.04As0.96 absorption layer. RTD mesas with ring contacts and an aperture for optical excitation of charge carriers were fabricated on the epitaxial layers. Electrical and optical properties of the RTDs were investigated for different thicknesses of a thin GaAs spacer layer incorporated between the AlGaAs tunnel barrier adjacent to the GaInNAs absorption layer. Illumination of the RTDs with laser light of 1.3 μm wavelength leads to a pronounced photo-effect with a sensitivities of around 103 A/W.

  8. Electronic and optical structure of 1.55 μm emitting GaInNAs quantum dots on different substrates

    NASA Astrophysics Data System (ADS)

    Tomić, Stanko

    2010-01-01

    We present a theoretical study which compares the electronic and optical properties of GaInNAs quantum dots (QD) with dilute amount of nitrogen (< 4%) on two different substrates, GaAs (001) and InP (001). The calculations are based on a 10 band k.p band-anti-crossing (BAC) Hamiltonian, incorporating valence, conduction and nitrogen-induced bands. We show that 1.55 μm emission can be achieved on both substrates through appropriate tailoring of the QD size. On GaAs, the dominant dipole matrix element is the of the in-plane light polarization, whereas on InP substrate, the dominant component is of the perpendicular light polarization. Our results also identify the different In and N QD compositions required for long-wavelength emission on both material substrates.

  9. Uncooled 2.5 Gb/s operation of 1.3 μm GaInNAs DQW lasers over a wide temperature range

    NASA Astrophysics Data System (ADS)

    Wei, Yongqiang; Gustavsson, Johan S.; Sadeghi, Mahdad; Wang, Shumin; Larsson, Anders; Savolainen, Pekka; Melanen, Petri; Sipilä, Pekko

    2006-04-01

    Ridge waveguide 1.3 μm GaInNAs lasers were fabricated from high quality double quantum well material grown by molecular beam epitaxy. Short cavity (250 μm) lasers have low threshold currents and small temperature dependencies of threshold current and slope efficiency, with a characteristic temperature of the threshold current as high as 200 K. The temperature stability allows for uncooled 2.5 Gb/s operation up to temperatures as high as 110°C with a constant modulation voltage and only the bias current adjusted for constant average output power. Under these conditions, an extinction ratio larger than 6 dB and a spectral rms-width smaller than 2 nm are obtained.

  10. Uncooled 2.5 Gb/s operation of 1.3 mum GaInNAs DQW lasers over a wide temperature range.

    PubMed

    Wei, Yongqiang; Gustavsson, Johan S; Sadeghi, Mahdad; Wang, Shumin; Larsson, Anders; Savolainen, Pekka; Melanen, Petri; Sipilä, Pekko

    2006-04-01

    Ridge waveguide 1.3 mum GaInNAs lasers were fabricated from high quality double quantum well material grown by molecular beam epitaxy. Short cavity (250 mum) lasers have low threshold currents and small temperature dependencies of threshold current and slope efficiency, with a characteristic temperature of the threshold current as high as 200 K. The temperature stability allows for uncooled 2.5 Gb/s operation up to temperatures as high as 110 degrees C with a constant modulation voltage and only the bias current adjusted for constant average output power. Under these conditions, an extinction ratio larger than 6 dB and a spectral rms-width smaller than 2 nm are obtained. PMID:19516408

  11. Correlation of the nanostructure with optoelectronic properties during rapid thermal annealing of Ga(NAsP) quantum wells grown on Si(001) substrates

    NASA Astrophysics Data System (ADS)

    Wegele, Tatjana; Beyer, Andreas; Gies, Sebastian; Zimprich, Martin; Heimbrodt, Wolfram; Stolz, Wolfgang; Volz, Kerstin

    2016-01-01

    Ga(NAsP) quantum wells grown pseudomorphically on Si substrate are promising candidates for optically active light sources in future optoelectronically integrated circuits on Si substrates. As the material is typically grown at low temperatures, it has to be thermally annealed after growth to remove defects and optimize optoelectronic properties. Here we show by quantitative transmission electron microscopy that two different kinds of structural development are associated with the annealing. First of all, the quantum well homogeneity improves with increasing annealing temperature. For annealing temperatures above 925 °C the composition becomes less homogeneous again. Second, voids form in the quantum well for annealing temperatures above 850 °C. Their density and size increase continuously with increasing annealing temperature. These results are correlated to the optical properties of the samples, where we find from temperature-dependent photoluminescence measurements two scales of disorder, which show the same temperature dependence as the structural properties.

  12. High-power temperature-stable GaInNAs distributed Bragg reflector laser emitting at 1180  nm.

    PubMed

    Korpijärvi, Ville-Markus; Viheriälä, Jukka; Koskinen, Mervi; Aho, Antti T; Guina, Mircea

    2016-02-15

    We report a single-mode 1180 nm distributed Bragg reflector (DBR) laser diode with a high output power of 340 mW. For the fabrication, we employed novel nanoimprint lithography that ensures cost-effective, large-area, conformal patterning and does not require regrowth. The output characteristics exhibited outstanding temperature insensitivity with a power drop of only 30% for an increase of the mount temperature from 20°C to 80°C. The high temperature stability was achieved by using GaInNAs/GaAs quantum wells (QWs), which exhibit improved carrier confinement compared to standard InGaAs/GaAs QWs. The corresponding characteristic temperatures were T0=110  K and T1=160  K. Moreover, we used a large detuning between the peak wavelength of the material gain at room temperature and the lasing wavelength determined by the DBR. In addition to good temperature characteristics, GaInNAs/GaAs QWs exhibit relatively low lattice strain with direct impact on improving the lifetime of laser diodes at this challenging wavelength range. The single-mode laser emission could be tuned by changing the mount temperature (0.1 nm/°C) or the drive current (0.5 pm/mA). The laser showed no degradation in a room-temperature lifetime test at 900 mA drive current. These compact and efficient 1180 nm laser diodes are instrumental for the development of compact frequency-doubled yellow-orange lasers, which have important applications in medicine and spectroscopy. PMID:26872156

  13. Test beam performance of CDF plug upgrade EM calorimeter

    SciTech Connect

    Fukui, Y.; CDF Upgrade Group

    1998-01-01

    CDF Plug Upgrade(tile-fiber) EM Calorimeter performed resolution of 15%/{radical}E{circle_plus}0.7% with non-linearity less than 1% in a energy range of 5-180 GeV at Fermilab Test Beam. Transverse uniformity of inside-tower-response of the EM Calorimeter was 2.2% with 56 GeV positron, which was reduced to 1.0% with response map correction. We observed 300 photo electron/GeV in the EM Calorimeter. Ratios of EM Calorimeter response to positron beam to that to {sup 137}Cs Source was stable within 1% in the period of 8 months.

  14. 2. HI PAR (ACQUISITION RADAR) TOWER AND ENLISTED MEN (EM) ...

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

    2. HI PAR (ACQUISITION RADAR) TOWER AND ENLISTED MEN (EM) BARRACKS WITH RADAR ATTACHED. - Nike Hercules Missile Battery Summit Site, Battery Control Administration & Barracks Building, Anchorage, Anchorage, AK

  15. Communication - An Effective Tool for Implementing ISO 14001/EMS

    SciTech Connect

    Rachel Damewood; Bowen Huntsman

    2004-04-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) received ISO 14001/EMS certification in June 2002. Communication played an effective role in implementing ISO 14001/EMS at the INEEL. This paper describes communication strategies used during the implementation and certification processes. The INEEL achieved Integrated Safety Management System (ISMS) and Voluntary Protection Program (VPP) Star status in 2001. ISMS implemented a formal process to plan and execute work. VPP facilitated worker involvement by establishing geographic units at various facilities with employee points of contact and management champions. The INEEL Environmental Management System (EMS) was developed to integrate the environmental functional area into its ISMS and VPP. Since the core functions of ISMS, VPP, and EMS are interchangeable, they were easy to integrate. Communication is essential to successfully implement an EMS. (According to ISO 14001 requirements, communication interacts with 12 other elements of the requirements.) We developed communication strategies that integrated ISMS, VPP, and EMS. For example, the ISMS, VPP, and EMS Web sites communicated messages to the work force, such as “VPP emphasizes the people side of doing business, ISMS emphasizes the system side of doing business, and EMS emphasizes the systems to protect the environment; but they all define work, identify and analyze hazards, and mitigate the hazards.” As a result of this integration, the work force supported and implemented the EMS. In addition, the INEEL established a cross-functional communication team to assist with implementing the EMS. The team included members from the Training and Communication organizations, VPP office, Pollution Prevention, Employee and Media Relations, a union representative, facility environmental support, and EMS staff. This crossfunctional team used various communication strategies to promote our EMS to all organization levels and successfully implemented EMS

  16. Reliability and Validity of the Novaco Anger Scale and Provocation Inventory (NAS-PI) and State-Trait Anger Expression Inventory-2 (STAXI-2) in Hispanic and Non-Hispanic White Student Samples

    ERIC Educational Resources Information Center

    Culhane, Scott E.; Morera, Osvaldo F.

    2010-01-01

    This project tested the State-Trait Anger Expression Inventory-2 (STAXI-2) and the Novaco Anger Scale-Provocation Inventory (NAS-PI) in a sample of U.S. Hispanic (n = 257) and U.S. non-Hispanic White (n = 246) undergraduate students. Internal consistency, subscale correlations, convergent validity with the Multidimensional Anger Inventory (MAI),…

  17. EM threat analysis for wireless systems.

    SciTech Connect

    Burkholder, R. J. (Ohio State University Electroscience Laboratory); Mariano, Robert J.; Schniter, P. (Ohio State University Electroscience Laboratory); Gupta, I. J. (Ohio State University Electroscience Laboratory)

    2006-06-01

    Modern digital radio systems are complex and must be carefully designed, especially when expected to operate in harsh propagation environments. The ability to accurately predict the effects of propagation on wireless radio performance could lead to more efficient radio designs as well as the ability to perform vulnerability analyses before and after system deployment. In this report, the authors--experts in electromagnetic (EM) modeling and wireless communication theory--describe the construction of a simulation environment that is capable of quantifying the effects of wireless propagation on the performance of digital communication.

  18. Stochastic EM-based TFBS motif discovery with MITSU

    PubMed Central

    Kilpatrick, Alastair M.; Ward, Bruce; Aitken, Stuart

    2014-01-01

    Motivation: The Expectation–Maximization (EM) algorithm has been successfully applied to the problem of transcription factor binding site (TFBS) motif discovery and underlies the most widely used motif discovery algorithms. In the wider field of probabilistic modelling, the stochastic EM (sEM) algorithm has been used to overcome some of the limitations of the EM algorithm; however, the application of sEM to motif discovery has not been fully explored. Results: We present MITSU (Motif discovery by ITerative Sampling and Updating), a novel algorithm for motif discovery, which combines sEM with an improved approximation to the likelihood function, which is unconstrained with regard to the distribution of motif occurrences within the input dataset. The algorithm is evaluated quantitatively on realistic synthetic data and several collections of characterized prokaryotic TFBS motifs and shown to outperform EM and an alternative sEM-based algorithm, particularly in terms of site-level positive predictive value. Availability and implementation: Java executable available for download at http://www.sourceforge.net/p/mitsu-motif/, supported on Linux/OS X. Contact: a.m.kilpatrick@sms.ed.ac.uk PMID:24931999

  19. CryoEM at IUCrJ: a new era

    PubMed Central

    Subramaniam, Sriram; Kühlbrandt, Werner; Henderson, Richard

    2016-01-01

    In this overview, we briefly outline recent advances in electron cryomicroscopy (cryoEM) and explain why the journal IUCrJ, published by the International Union of Crystallography, could provide a natural home for publications covering many present and future developments in the cryoEM field. PMID:26870375

  20. 7 CFR 1945.20 - Making EM loans available.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Secretary in making a decision on the requested natural disaster determination. (4) The Secretary will... 7 Agriculture 13 2012-01-01 2012-01-01 false Making EM loans available. 1945.20 Section 1945.20...) PROGRAM REGULATIONS (CONTINUED) EMERGENCY Disaster Assistance-General § 1945.20 Making EM loans...

  1. 7 CFR 1945.20 - Making EM loans available.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Secretary in making a decision on the requested natural disaster determination. (4) The Secretary will... 7 Agriculture 13 2011-01-01 2009-01-01 true Making EM loans available. 1945.20 Section 1945.20...) PROGRAM REGULATIONS (CONTINUED) EMERGENCY Disaster Assistance-General § 1945.20 Making EM loans...

  2. Click-EM for imaging metabolically tagged nonprotein biomolecules.

    PubMed

    Ngo, John T; Adams, Stephen R; Deerinck, Thomas J; Boassa, Daniela; Rodriguez-Rivera, Frances; Palida, Sakina F; Bertozzi, Carolyn R; Ellisman, Mark H; Tsien, Roger Y

    2016-06-01

    EM has long been the main technique for imaging cell structures with nanometer resolution but has lagged behind light microscopy in the crucial ability to make specific molecules stand out. Here we introduce click-EM, a labeling technique for correlative light microscopy and EM imaging of nonprotein biomolecules. In this approach, metabolic labeling substrates containing bioorthogonal functional groups are provided to cells for incorporation into biopolymers by endogenous biosynthetic machinery. The unique chemical functionality of these analogs is exploited for selective attachment of singlet oxygen-generating fluorescent dyes via bioorthogonal 'click chemistry' ligations. Illumination of dye-labeled structures generates singlet oxygen to locally catalyze the polymerization of diaminobenzidine into an osmiophilic reaction product that is readily imaged by EM. We describe the application of click-EM in imaging metabolically tagged DNA, RNA and lipids in cultured cells and neurons and highlight its use in tracking peptidoglycan synthesis in the Gram-positive bacterium Listeria monocytogenes. PMID:27110681

  3. The Orthogonally Partitioned EM Algorithm: Extending the EM Algorithm for Algorithmic Stability and Bias Correction Due to Imperfect Data.

    PubMed

    Regier, Michael D; Moodie, Erica E M

    2016-05-01

    We propose an extension of the EM algorithm that exploits the common assumption of unique parameterization, corrects for biases due to missing data and measurement error, converges for the specified model when standard implementation of the EM algorithm has a low probability of convergence, and reduces a potentially complex algorithm into a sequence of smaller, simpler, self-contained EM algorithms. We use the theory surrounding the EM algorithm to derive the theoretical results of our proposal, showing that an optimal solution over the parameter space is obtained. A simulation study is used to explore the finite sample properties of the proposed extension when there is missing data and measurement error. We observe that partitioning the EM algorithm into simpler steps may provide better bias reduction in the estimation of model parameters. The ability to breakdown a complicated problem in to a series of simpler, more accessible problems will permit a broader implementation of the EM algorithm, permit the use of software packages that now implement and/or automate the EM algorithm, and make the EM algorithm more accessible to a wider and more general audience. PMID:27227718

  4. Quantum oscillations and interference effects in strained n- and p-type modulation doped GaInNAs/GaAs quantum wells

    NASA Astrophysics Data System (ADS)

    Sarcan, F.; Nutku, F.; Donmez, O.; Kuruoglu, F.; Mutlu, S.; Erol, A.; Yildirim, S.; Arikan, M. C.

    2015-08-01

    We have performed magnetoresistance measurements on n- and p-type modulation doped GaInNAs/GaAs quantum well (QW) structures in both the weak (B  < 0.08 T) and the high magnetic field (up to 18 T) at 75 mK and 6 K. We observe that the quantum oscillations in {ρxx} and quantum Hall effect (QHE) plateaus in {ρxy} are affected from the presence of the nitrogen in the III-V lattice. The enhancement of N-related scatterings and electron effective mass with increasing nitrogen causes lower electron mobility and higher two-dimensional (2D) electron density, leading to suppressed QHE plateaus in {ρxy} up to 7 T at 6 K. The Shubnikov de Haas (SdH) oscillations develop at lower magnetic fields for higher mobility samples at 6 K and the amplitude of SdH oscillations decreases with increasing nitrogen composition. The well-pronounced QHE plateaus are observed at 75 mK and at higher magnetic fields up to 18 T, for the p-type sample. For n-type samples, the observed anomalies in the characteristic of QHE is attributed the nitrogen-related disorders and overlapping of fluctuating Landau levels. The low magnetic field measurements at 75 mK reveal that the n-type samples exhibit weak antilocalization, whereas weak localization is observed for the p-type sample. The observation of weak antilocalization is an indication of strong electron spin-orbit interactions. The low field magnetoresistance traces are used to extract the spin coherence, phase coherence and elastic scattering times as well Rashba parameters and spin-splitting energy. The calculated Rashba parameters for nitrogen containing samples reveal that the nitrogen composition is a significant parameter to determine the degree of the spin-orbit interactions. Consequently, GaInNAs-based QW structures with various nitrogen compositions can be beneficial to adjust the spin-orbit coupling strength and may be used as a candidate for spintronics applications.

  5. Vertical Distribution of Bacterial Communities in the Indian Ocean as Revealed by Analyses of 16S rRNA and nasA Genes.

    PubMed

    Jiang, Xuexia; Jiao, Nianzhi

    2016-09-01

    Bacteria play an important role in the marine biogeochemical cycles. However, research on the bacterial community structure of the Indian Ocean is scarce, particularly within the vertical dimension. In this study, we investigated the bacterial diversity of the pelagic, mesopelagic and bathypelagic zones of the southwestern Indian Ocean (50.46°E, 37.71°S). The clone libraries constructed by 16S rRNA gene sequence revealed that most phylotypes retrieved from the Indian Ocean were highly divergent from those retrieved from other oceans. Vertical differences were observed based on the analysis of natural bacterial community populations derived from the 16S rRNA gene sequences. Based on the analysis of the nasA gene sequences from GenBank database, a pair of general primers was developed and used to amplify the bacterial nitrate-assimilating populations. Environmental factors play an important role in mediating the bacterial communities in the Indian Ocean revealed by canonical correlation analysis. PMID:27407295

  6. UAS in the NAS Air Traffic Controller Acceptability Study-1: The Effects of Horizontal Miss Distances on Simulated UAS and Manned Aircraft Encounters

    NASA Technical Reports Server (NTRS)

    Ghatas, Rania W.; Comstock, James R., Jr.; Consiglio, Maria C.; Chamberlain, James P.; Hoffler, Keith D.

    2015-01-01

    This study examined air traffic controller acceptability ratings based on the effects of differing horizontal miss distances (HMDs) for encounters between UAS and manned aircraft. In a simulation of the Dallas/Fort Worth (DFW) East-side airspace, the CAS-1 experiment at NASA Langley Research Center enlisted fourteen recently retired DFW air traffic controllers to rate well-clear volumes based on differing HMDs that ranged from 0.5 NM to 3.0 NM. The controllers were tasked with rating these HMDs from "too small" to "too excessive" on a defined, 1-5, scale and whether these distances caused any disruptions to the controller and/or to the surrounding traffic flow. Results of the study indicated a clear favoring towards a particular HMD range. Controller workload was also measured. Data from this experiment and subsequent experiments will play a crucial role in the FAA's establishment of rules, regulations, and procedures to safely and efficiently integrate UAS into the NAS.

  7. Photoluminescence study of InAs quantum dots embedded in GaNAs strain compensating layer grown by metalorganic-molecular-beam epitaxy

    NASA Astrophysics Data System (ADS)

    Zhang, X. Q.; Ganapathy, Sasikala; Kumano, Hidekazu; Uesugi, Kasturi; Suemune, Ikuo

    2002-12-01

    Self-assembled InAs quantum dots (QDs) embedded in GaN0.007As0.993 strain compensating layers have been grown by metalorganic-molecular-beam epitaxy on a GaAs (001) substrate with a high density of 1×1011 cm-2. The photoluminescence properties have been studied for two periods of InAs quantum dots layers embedded in GaN0.007As0.993 strain compensating layers. Four well-resolved excited-state peaks in the photoluminescence spectra have been observed from these highly packed InAs QDs embedded in the GaN0.007As0.993 strain compensating layers. This indicates that the InAs QDs are uniformly formed and that the excited states in QDs due to the quantum confinement effect are well defined. This is explained by tensile strain in GaNAs layers instead of the usual GaAs layers to relieve the compressive strain formed in InAs QDs to keep the total strain of the system at a minimum.

  8. X-ray Diffraction Measurement of GaInNAs/GaAs Double Quantum Well Structures with Novel Analysis Method for Broadening Factors

    NASA Astrophysics Data System (ADS)

    Nakashima, Kiichi; Tateno, Kouta

    2006-09-01

    The structural deterioration of GaInNAs/GaAs double-quantum-well (DQW) samples was analyzed by X-ray diffraction measurement with a novel peak broadening method. We effectively analyzed broadening properties by taking the difference between 004 X-ray satellite profiles measured with two different types of scanning configuration: a conventional configuration without a receiving slit and that with an analyzer crystal placed in front of a receiving detector. We found that the broadening due to structural deterioration can be simply and clearly analyzed by focusing attention on the difference between two types of profile shape, particularly at the valley minimum parts of satellite patterns. It is demonstrated that the difference at the valley minimum parts clearly represents various aspects of the deterioration of DQW structures. Particularly, it is remarkable that not only the degree of deterioration of the DQW structures but also the change in broadening mechanism due to the proceeding deterioration can be effectively analyzed. We propose and formulate a new simple method for analyzing the difference in valley shape by introducing two characteristic indices representing the difference. It is experimentally demonstrated that the new method is effective in both sensitively detecting and characterizing the deterioration of DQW structures by identifying broadening due to tilt distribution or lateral size effects of mosaic structures. From these results, it is concluded that the analysis of the valley minimum parts of profiles is a simple and effective tool for X-ray diffraction measurement.

  9. Pratt and Whitney/Boeing Engine Validation of Noise Reduction Concepts: Final Report for NASA Contract NAS3-97144, Phase 1

    NASA Technical Reports Server (NTRS)

    Mathews, Douglas; Bock, Larry A.; Bielak, Gerald W.; Dougherty, R. P.; Premo, John W.; Scharpf, Dan F.; Yu, Jia

    2014-01-01

    Major airports in the world's air transportation systems face a serious problem in providing greater capacity to meet the ever increasing demands of air travel. This problem could be relieved if airports are allowed to increase their operating time, now restricted by curfews and by relaxing present limits on takeoffs and landings. The key operational issue in extending the present curfews is noise. In response to these increasing restrictive noise regulations, NASA has launched a program to validate through engine testing, noise reduction concepts and technologies that have evolved from the Advanced Subsonic Technologies (AST) Noise Reduction Program. The goal of this AST program was to develop and validate technology that reduces engine noise and improves nacelle suppression effectiveness relative to 1992 technology. Contract NAS3-97144 titled "Engine Validation of Noise Reduction Concepts" (EVNRC) was awarded to P&W on August 12, 1997 to conduct full scale noise reduction tests in two Phases on a PW4098 engine. The following Section 1.2 provides a brief description of the overall program. The remainder of this report provides a detailed documentation of Phase I of the program.

  10. Evaluation of Fracture Azimuth by EM Wave and Elastic Wave

    NASA Astrophysics Data System (ADS)

    Feng, X.; Wang, Q.; Liu, C.; Lu, Q.; Zeng, Z.; Liang, W.; Yu, Y.; Ren, Q.

    2013-12-01

    Fracture system plays an important role in the development of underground energy, for example enhanced geothermal system (EGS), oil shale and shale gas, etc. Therefore, it becomes more and more important to detect and evaluate the fracture system. Geophysical prospecting is an useful method to evaluate the characteristics of the subsurface fractures. Currently, micro-seismology, multi-wave seismic exploration, and electromagnetic (EM) survey are reported to be used for the purpose. We are studying a method using both elastic wave and EM wave to detect and evaluate the fracture azimuth in laboratory. First, we build a 3D horizontal transverse isotropy (HTI) model, shown in the figure 1, by dry parallel fractures system, which was constructed by plexiglass plates and papers. Then, we used the ultrasonic system to obtain reflected S-wave data. Depending on the shear wave splitting, we evaluated the fracture azimuth by the algorithm of Pearson correlation coefficient. In addition, we used the full Polarimetric ultra wide band electromagnetic (FP-UWB-EM) wave System, shown in the figure 2, to obtain full polarimetric reflected EM-wave data. Depending on the rotation of the EM wave polarimetry, we evaluated the fracture azimuth by the the ration between maximum amplitude of co-polarimetric EM wave and maximum amplitude of cross-polarimetric EM wave. Finally, we used both EM-wave data and S-wave data to evaluate the fracture azimuth by the method of cross plot and statistical mathematics. To sum up, we found that FP-UWB-EM wave can be used to evaluated the fracture azimuth and is more accurate than ultrasound wave. Also joint evaluation using both data could improve the precision.

  11. Refinement of atomic models in high resolution EM reconstructions using Flex-EM and local assessment

    PubMed Central

    Joseph, Agnel Praveen; Malhotra, Sony; Burnley, Tom; Wood, Chris; Clare, Daniel K.; Winn, Martyn; Topf, Maya

    2016-01-01

    As the resolutions of Three Dimensional Electron Microscopic reconstructions of biological macromolecules are being improved, there is a need for better fitting and refinement methods at high resolutions and robust approaches for model assessment. Flex-EM/MODELLER has been used for flexible fitting of atomic models in intermediate-to-low resolution density maps of different biological systems. Here, we demonstrate the suitability of the method to successfully refine structures at higher resolutions (2.5–4.5 Å) using both simulated and experimental data, including a newly processed map of Apo-GroEL. A hierarchical refinement protocol was adopted where the rigid body definitions are relaxed and atom displacement steps are reduced progressively at successive stages of refinement. For the assessment of local fit, we used the SMOC (segment-based Manders’ overlap coefficient) score, while the model quality was checked using the Qmean score. Comparison of SMOC profiles at different stages of refinement helped in detecting regions that are poorly fitted. We also show how initial model errors can have significant impact on the goodness-of-fit. Finally, we discuss the implementation of Flex-EM in the CCP-EM software suite. PMID:26988127

  12. Refinement of atomic models in high resolution EM reconstructions using Flex-EM and local assessment.

    PubMed

    Joseph, Agnel Praveen; Malhotra, Sony; Burnley, Tom; Wood, Chris; Clare, Daniel K; Winn, Martyn; Topf, Maya

    2016-05-01

    As the resolutions of Three Dimensional Electron Microscopic reconstructions of biological macromolecules are being improved, there is a need for better fitting and refinement methods at high resolutions and robust approaches for model assessment. Flex-EM/MODELLER has been used for flexible fitting of atomic models in intermediate-to-low resolution density maps of different biological systems. Here, we demonstrate the suitability of the method to successfully refine structures at higher resolutions (2.5-4.5Å) using both simulated and experimental data, including a newly processed map of Apo-GroEL. A hierarchical refinement protocol was adopted where the rigid body definitions are relaxed and atom displacement steps are reduced progressively at successive stages of refinement. For the assessment of local fit, we used the SMOC (segment-based Manders' overlap coefficient) score, while the model quality was checked using the Qmean score. Comparison of SMOC profiles at different stages of refinement helped in detecting regions that are poorly fitted. We also show how initial model errors can have significant impact on the goodness-of-fit. Finally, we discuss the implementation of Flex-EM in the CCP-EM software suite. PMID:26988127

  13. Environmental Education and Development Division (EM-522). Annual report, Fiscal year 1993

    SciTech Connect

    Not Available

    1993-12-31

    The Environmental Education and Development Division (EM-522) is one of three divisions within the Office of Technology Integration and Environmental Education and Development (EM-52) in Environmental Restoration and Waste Management`s (EM`s) Office of Technology Development (EM-50). The primary design criterion for EM-522 education activities is directly related to meeting EM`s goal of environmental compliance on an accelerated basis and cleanup of the 1989 inventory of inactive sites and facilities by the year 2019. Therefore, EM-522`s efforts are directed specifically toward stimulating knowledge and capabilities to achieve the goals of EM while contributing to DOE`s overall goal of increasing scientific, mathematical, and technical literacy and competency. This report discusses fiscal year 1993 activities.

  14. Electromagnetic optimization of EMS-MAGLEV systems

    SciTech Connect

    Andriollo, M.; Martinelli, G.; Morini, A.; Tortella, A.

    1998-07-01

    In EMS-MAGLEV high-speed transport systems, devices for propulsion, levitation and contactless on-board electric power transfer are combined in a single electromagnetic structure. The strong coupling among the windings affects the performance of each device and requires the utilization of numerical codes. The paper describes an overall optimization procedure, based on a suitable mathematical model of the system, which takes into account several items of the system performance. The parameters of the model are calculated by an automated sequence of FEM analyses of the configuration. Both the linear generator output characteristics and the propulsion force ripple are improved applying the procedure to a reference configuration. The results are compared with the results obtained by a sequence of partial optimizations operating separately on two different subsets of the geometric parameters.

  15. DOE EM industry programs robotics development

    SciTech Connect

    Staubly, R.; Kothari, V.

    1997-12-01

    The Office of Science and Technology (OST) manages an aggressive program for RD&D, as well as testing and evaluation for the U.S. Department of Energy`s (DOE) Environmental Management (EM) organization. The goal is to develop new and improved environmental restoration and waste management technologies to clean up the inventory of the DOE weapons complex faster, safer, and cheaper than is possible with currently available technologies. OST has organized technology management activities along focus teams for each major problem area. There are currently five focus areas: decontamination and decommissioning, tanks, subsurface contaminants, mixed waste, and plutonium. In addition, OST is pursuing research and development (R&D) that cuts across these focus areas by having applications in two or more focus areas. Currently, there are three cross-cutting programs: the robotics technology development; characterization, monitoring, and sensor technologies; and efficient separations and processing.

  16. Online EM with weight-based forgetting.

    PubMed

    Celaya, Enric; Agostini, Alejandro

    2015-05-01

    In the online version of the EM algorithm introduced by Sato and Ishii ( 2000 ), a time-dependent discount factor is introduced for forgetting the effect of the old estimated values obtained with an earlier, inaccurate estimator. In their approach, forgetting is uniformly applied to the estimators of each mixture component depending exclusively on time, irrespective of the weight attributed to each unit for the observed sample. This causes an excessive forgetting in the less frequently sampled regions. To address this problem, we propose a modification of the algorithm that involves a weight-dependent forgetting, different for each mixture component, in which old observations are forgotten according to the actual weight of the new samples used to replace older values. A comparison of the time-dependent versus the weight-dependent approach shows that the latter improves the accuracy of the approximation and exhibits much greater stability. PMID:25710091

  17. Memória fonológica em crianças bilíngues bimodais e crianças com implante coclear

    PubMed Central

    de Quadros, Ronice Müller; Cruz, Carina Rebello; Pizzio, Aline Lemos

    2014-01-01

    RESUMO Este estudo comparou o desempenho de crianças bilíngues bimodais ouvintes (filhas de pais surdos) e crianças surdas usuárias de implante coclear (filhas de pais surdos e de pais ouvintes), com diferentes contextos de acesso à Língua Brasileira de Sinais (Libras), em tarefas que envolvem memória fonologica. Os testes utilizados foram: Teste de Pseudopalavras (Santos e Bueno, 2003) e Teste de Pseudosinais (desenvolvido pelos pesquisadores responsáveis pelo Projeto ‘Desenvolvimento Bilíngue Bimoda’). Além disso, foram incluídos dois grupos de controle, formados por crianças surdas (usuarias de Libras), e adultos bilíngues bimodais ouvintes. Na análise dos resultados, em relação ao desempenho entre os dois grupos testados foi constatado que o grupo de crianças bilíngues bimodais ouvintes apresentou desempenho superior, nos dois testes. No entanto, ao ser analisado o desempenho da criança surda usuaria de implante coclear, filha de pais surdos, que possui acesso irrestrito à Libras e comparado com o das crianças surdas usuárias de implante coclear, que possuem acesso restrito à Libras, foi constatado que o seu desempenho foi semelhante ao do grupo de crianças bilíngues bimodais ouvintes. As crianças surdas usuárias de implante coclear com acesso restrito à Libras e, portanto, com acesso maior ao Português apresentaram escores mais baixos nas tarefas, principalmente do teste em Português. Os resultados sugerem que as crianças surdas usuárias de implante coclear em processo de aquisição da línguagem podem se beneficiar com o acesso irrestrito à Libras, atingindo inclusive desempenho semelhante a de crianças bilíngues bimodais ouvintes. PMID:25110473

  18. Processing of Structurally Heterogeneous Cryo-EM Data in RELION.

    PubMed

    Scheres, S H W

    2016-01-01

    This chapter describes algorithmic advances in the RELION software, and how these are used in high-resolution cryo-electron microscopy (cryo-EM) structure determination. Since the presence of projections of different three-dimensional structures in the dataset probably represents the biggest challenge in cryo-EM data processing, special emphasis is placed on how to deal with structurally heterogeneous datasets. As such, this chapter aims to be of practical help to those who wish to use RELION in their cryo-EM structure determination efforts. PMID:27572726

  19. Test beam performance of CDF plug upgrade EM calorimeter

    SciTech Connect

    Fukui, Y.

    1998-11-01

    CDF Plug Upgrade(tile-fiber) EM Calorimeter performed resolution of 15{percent}/{radical} (E) {circle_plus}0.7{percent} with non-linearity less than 1{percent} in a energy range of 5{endash}180 GeV at Fermilab Test Beam. Transverse uniformity of inside-tower-response of the EM Calorimeter was 2.2{percent} with 56 GeV positron, which was reduced to 1.0{percent} with response map correction. We observed 300 photo electron/GeV in the EM Calorimeter. Ratios of EM Calorimeter response to positron beam to that to {sup 137}C{sub s} Source was stable within 1{percent} in the period of 8 months. {copyright} {ital 1998 American Institute of Physics.}

  20. E.M. and Hadronic Shower Simulation with FLUKA

    SciTech Connect

    Battistoni, G.; Fasso, A.; Ferrari, A.; Ranft, J.; Rubbia, A.; Sala, P.R.; /INFN, Milan /SLAC /CERN /Siegen U. /Zurich, ETH

    2005-10-03

    A description of the main features of e.m. and hadronic shower simulation models used in the FLUKA code is summarized and some recent applications are discussed. The general status of the FLUKA project is also reported.

  1. 7 CFR 759.6 - EM to be made available.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Agriculture under the Plant Protection Act or the animal quarantine laws, as defined in section 2509 of the Food, Agriculture, Conservation, and Trade Act of 1990, automatically authorizes EM for production...

  2. 7 CFR 759.6 - EM to be made available.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Agriculture under the Plant Protection Act or the animal quarantine laws, as defined in section 2509 of the Food, Agriculture, Conservation, and Trade Act of 1990, automatically authorizes EM for production...

  3. NASA EM Followup of LIGO-Virgo Candidate Events

    NASA Technical Reports Server (NTRS)

    Blackburn, Lindy L.

    2011-01-01

    We present a strategy for a follow-up of LIGO-Virgo candidate events using offline survey data from several NASA high-energy photon instruments aboard RXTE, Swift, and Fermi. Time and sky-location information provided by the GW trigger allows for a targeted search for prompt and afterglow EM signals. In doing so, we expect to be sensitive to signals which are too weak to be publicly reported as astrophysical EM events.

  4. EM Telemetry Tool for Deep Well Drilling Applications

    SciTech Connect

    Jeffrey M. Gabelmann

    2005-11-15

    This final report discusses the successful development and testing of a deep operational electromagnetic (EM) telemetry system, produced under a cooperative agreement with the United States Department of Energy's National Energy Technology Laboratory. This new electromagnetic telemetry system provides a wireless communication link between sensors deployed deep within oil and gas wells and data acquisition equipment located on the earth's surface. EM based wireless telemetry is a highly appropriate technology for oil and gas exploration in that it avoids the need for thousands of feet of wired connections. In order to achieve the project performance objectives, significant improvements over existing EM telemetry systems were made. These improvements included the development of new technologies that have improved the reliability of the communications link while extending operational depth. A key element of the new design is the incorporation of a data-fusion methodology which enhances the communication receiver's ability to extract very weak signals from large amounts of ambient environmental noise. This innovative data-fusion receiver based system adapts advanced technologies, not normally associated with low-frequency communications, and makes them work within the harsh drilling environments associated with the energy exploration market. Every element of a traditional EM telemetry system design, from power efficiency to reliability, has been addressed. The data fusion based EM telemetry system developed during this project is anticipated to provide an EM tool capability that will impact both onshore and offshore oil and gas exploration operations, for conventional and underbalanced drilling applications.

  5. Gradiente radial de [Mg/Fe] em duas galáxias elípticas

    NASA Astrophysics Data System (ADS)

    Milone, A.; Capelato, H.

    2003-08-01

    Basicamente, são propostos dois cenários de evolução quí mio-dinâmico para os sistemas esferoidais: (i) o hierárquico através da fusão e/ou acresção de sub-sistemas com ou sem surtos de formação estelar, e (ii) o colapso monolí tico dissipativo com formação estelar interrompida por um vento galáctico. Ambos, dentro de certos limites, conseguem explicar os gradientes internos de metalicidade estelar presentes nas galáxias elí pticas bem como a relação observada entre a metalicidade central e a massa (Mg20 vs. log sv0). No entanto, nenhum prevê uma variação interna para a razão de abundâncias Mg/Fe que indiretamente define a escala temporal da formação estelar. Empregamos a espectroscopia óptica de fenda longa com a finalidade de recuperar as histórias de formação estelar, de enriquecimento quí mico e da dinâmica dentro de determinadas regiões das galáxias. Os espectros de média resolução (FWHM = 7,1 Å) e escala angular de 1,092 arcsec/pixel foram coletados com o telescópio 1,60m do OPD/LNA. Comparamos nossas medidas de linhas de absorção com resultados espectrofotométricos de modelos de populações estelares simples - mais especificamente os í ndices do Sistema Lick como Mg2, Mg b, < Fe > e Hb - a fim de se investigar as variações internas de [Fe/H], [Mg/Fe] e idade. Para duas galáxias elí pticas, NGC 1052 e NGC 7796, pertencentes a ambientes de baixa densidade, encontramos uma variação radial da razão Mg/Fe decrescente do centro para fora em regiões de 0,6 e 1 raio efetivo respectivamente. Discutimos alguns cenários de enriquecimento quí mico para estas duas galáxias.

  6. Fisica a escala de Planck usando o principio de incerteza generalizado: efeitos nas flutuações primordiais e buracos negros

    NASA Astrophysics Data System (ADS)

    Horvath, J. E.; Custódio, P. S.

    2003-08-01

    Em escalas proximas à escala de Planck todas as teorias perturbativas de cordas produzem essenciamente a mesma relação de conmutação entre as coordenadas e impulsos (a chamada "álgebra deformada"), permitindo assim estudar a física resultante independentemente dos detalhes da teoria de cordas que seja considerada correta. Este resultado completamente geral, que inclui as interações gravitacionais junto com o resto dos campos pode ser considerada uma versão generalizada (GUP) do Princípio de Incerteza de Heisenberg. Aplicamos neste trabalho essas relações de conmutação para dois sistemas físicos bem definidos: buracos negros de massas próximas à massa de Planck, e flutuações quânticas em pequenas escalas antes do universo sofrer inflação. Obtemos dois resultados concretos dos efeitos do GUP : o primeiro é que o GUP impede a evaporação completa de buracos negros microscópicos na extensão do formalismo semiclássico, deixando assim remanescentes de pequena massa que já foram postulados como candidatos a matéria escura. O segundo resultado é o 'smoothing' das flutuações primordiais em pequenas escalas que levariam à produção de buracos negros primordiais após a inflação, impedindo assim a produção abundante destes últimos e predizendo abundancias atuais bem menores do que os limites disponíveis. Concluimos que, analogamente a utilização do Princípio de Incerteza de Heisenberg para estudar e determinar propriedades fundamentais das interações sem gravitação, o GUP e uma ferramenta poderosa para estudar uma ampla variedade de sistemas trans-Planckianos e predizer seu comportamento dispensando cálculos mais detalhados proprios da teoria quântica da gravitação.

  7. Modelo de atmosfera solar ajustado às observações do raio solar em 17GHz

    NASA Astrophysics Data System (ADS)

    Selhorst, C. L.; Silva, A. V. R.; Costa, J. E. R.

    2003-08-01

    O estudo das variações do raio solar durante o ciclo de atividades do Sol e das diferenças em relação à sua distribuição angular nos fornece informações importantes sobre as mudanças na estrutura da atmosfera solar. Neste trabalho foram analisados mais de 3600 mapas do Sol em 17 GHz obtidos pelo Rádio Heliógrafo de Nobeyama (NoRH), durante 1 ciclo de atividade solar (1992-2003). O raio solar foi definido no ponto onde a temperatura de brilho do mapa era equivalente à metade da temperatura do Sol calmo (temperatura mais comum no mapa).Em relação à sua variação ao longo do ciclo solar, o estudo foi dividido em duas partes: a) ajuste de uma circunferência a pontos distribuídos ao redor do Sol todo. Este estudo mostrou uma variação correlacionada com o ciclo de atividade do Sol. b) ajuste da circunferência a pontos situados somente nas regiões polares. Neste caso os resultados mostraram que o raio polar sofre pouca variação durante o ciclo, com tendência à anticorrelação com este. Além disto, a média do raio polar, durante o período analisado, foi 1" menor que o raio medido no Sol todo. Para estudar a distribuição angular do raio solar, comparamos a média da distribuição de 10 mapas no período de mínima atividade solar com a média de 10 mapas no período de máximo, este estudo mostrou um grande aumento do raio na região equatorial no período de máxima atividade solar. As medidas do raio foram usadas como um dos parâmetros para a criação de um modelo atmosférico (além da temperatura de brilho do Sol e do abrilhantamento do limbo observado), onde mostramos que um modelo atmosférico com a região de transição situada a 3500 km fornece um raio 5" menor que as medidas observacionais. Esta incompatibilidade do modelo com os dados observacionais foi contornada com a inclusão de espículas, estas fazem com que o raio solar aumente proporcionalmente à altura que estas atingem na atmosfera solar. A anticorrelação do raio

  8. A HF EM installation allowing simultaneous whole body and deep local EM hyperthermia.

    PubMed

    Mazokhin, V N; Kolmakov, D N; Lucheyov, N A; Gelvich, E A; Troshin, I I

    1999-01-01

    The structure and main features of a HF EM installation based upon a new approach for creating electromagnetic fields destined for whole body (WBH) and deep local (DLH) hyperthermia are discussed. The HF EM field, at a frequency of 13.56 MHz, is created by a coplanar capacity type applicator positioned under a distilled water filled bolus that the patient is lying on. The EM energy being released directly in the deep tissues ensures effective whole body heating to required therapeutic temperatures of up to 43.5 degrees C, whereas the skin temperature can be maintained as low as 39-40.5 degrees C. For DLH, the installation is equipped with additional applicators and a generator operating at a frequency of 40.68 MHz. High efficiency of the WBH applicator makes it possible to carry out the WBH procedure without any air-conditioning cabin. Due to this, a free access to the patient's body during the WBH treatment is provided and a simultaneous WBH/DLH or WBH/LH procedure by means of additional applicators is possible. Controllable power output in the range of 100-800 W at a frequency of 13.56 MHz and 50-350 W at a frequency of 40.68 MHz allows accurate temperature control during WBH, DLH and WBH/DLH procedures. SAR patterns created by the WBH and DLH applicators in a liquid muscle phantom and measured by means of a non-perturbing E-dipole are investigated. The scattered EM field strength measured in the vicinity of the operating installation during the WBH, DLH and WBH/DLH procedures does not exceed security standards. Examples of temperature versus time graphs in the course of WBH, DLH and WBH/DLH procedures in clinics are presented. The installation is successfully used in leading oncological institutions of Russia and Belarus, though combined WBH/DLH procedures are evidently more complicated and demand thorough planning and temperature measurements to avoid overheating. PMID:10458570

  9. Analysis of EM dataset with several sensor configurations obtained by the loop-loop EM survey on magnetic anomalies

    NASA Astrophysics Data System (ADS)

    CHOI, J.; Yi, M. J.; Sasaki, Y.; Son, J.; Nam, M. J.

    2015-12-01

    Most of mineral mines in Korea are located in rugged mountain area embedding small-scale anomalies. Loop-loop EM survey system can be a better choice for exploring those mines because no ground contact is required and portable loops are freely positioned. Survey design is very important for detecting small amount of mineral deposits efficiently and spatial limits of survey lines should be considered. Along a same survey line, surveys with different separations between a transmitter and a receiver are applicable. EM responses are calculated in a layered-earth model embedding magnetic anomalies and analyses considering electric conductivity and magnetic permeability are made for the loop-loop EM survey data. Combining EM dataset with multi-frequency and multi-separation slightly enhanced a reconstructed image. Loop-loop EM survey using PROMOIS system was conducted on a small magnetite mine. Inversion with and without considering magnetic permeability was conducted for EM data with multi-frequency and multi-separation between a transmitter and a receiver.

  10. DOE EM industry programs robotics development

    SciTech Connect

    Staubly, R.; Kothari, V.

    1998-12-31

    The Office of Science and Technology (OST) manages an aggressive program for RD and D, as well as testing and evaluation for the Department of Energy`s (DOE`s) Environmental Management (EM) organization. The goal is to develop new and improved environmental restoration and waste management technologies to clean up the inventory of the DOE weapons complex faster, safer, and cheaper than is possible with currently available technologies. Robotic systems reduce worker exposure to the absolute minimum, while providing proven, cost-effective, and, for some applications, the only acceptable technique for addressing challenging problems. Development of robotic systems for remote operations occurs in three main categories: tank waste characterization and retrieval; decontamination and dismantlement; and characterization, mapping, and inspection systems. In addition, the Federal Energy Technology Center (FETC) has some other projects which fall under the heading of supporting R and D. The central objective of all FETC robotic projects is to make robotic systems more attractive by reducing costs and health risks associated with the deployment of robotic technologies in the cleanup of the nuclear weapons complex. This will be accomplished through development of robots that are cheaper, faster, safer, and more reliable, as well as more straightforward to modify/adapt and more intuitive to operate with autonomous capabilities and intelligent controls that prevent accidents and optimize task execution.

  11. Databases and Archiving for CryoEM.

    PubMed

    Patwardhan, A; Lawson, C L

    2016-01-01

    CryoEM in structural biology is currently served by three public archives-EMDB for 3DEM reconstructions, PDB for models built from 3DEM reconstructions, and EMPIAR for the raw 2D image data used to obtain the 3DEM reconstructions. These archives play a vital role for both the structural community and the wider biological community in making the data accessible so that results may be reused, reassessed, and integrated with other structural and bioinformatics resources. The important role of the archives is underpinned by the fact that many journals mandate the deposition of data to PDB and EMDB on publication. The field is currently undergoing transformative changes where on the one hand high-resolution structures are becoming a routine occurrence while on the other hand electron tomography is enabling the study of macromolecules in the cellular context. Concomitantly the archives are evolving to best serve their stakeholder communities. In this chapter, we describe the current state of the archives, resources available for depositing, accessing, searching, visualizing and validating data, on-going community-wide initiatives and opportunities, and challenges for the future. PMID:27572735

  12. Degradation of Benzodiazepines after 120 Days of EMS Deployment

    PubMed Central

    McMullan, Jason T.; Jones, Elizabeth; Barnhart, Bruce; Denninghoff, Kurt; Spaite, Daniel; Zaleski, Erin; Silbergleit, Robert

    2014-01-01

    Introduction EMS treatment of status epilepticus improves outcomes, but the benzodiazepine best suited for EMS use is unclear, given potential high environmental temperature exposures. Objective To describe the degradation of diazepam, lorazepam, and midazolam as a function of temperature exposure and time over 120 days of storage on active EMS units. Methods Study boxes containing vials of diazepam, lorazepam, and midazolam were distributed to 4 active EMS units in each of 2 EMS systems in the southwestern United States during May–August 2011. The boxes logged temperature every minute and were stored in EMS units per local agency policy. Two vials of each drug were removed from each box at 30-day intervals and underwent high-performance liquid chromatography to determine drug concentration. Concentration was analyzed as mean (and 95%CI) percent of initial labeled concentration as a function of time and mean kinetic temperature (MKT). Results 192 samples were collected (2 samples of each drug from each of 4 units per city at 4 time-points). After 120 days, the mean relative concentration (95%CI) of diazepam was 97.0% (95.7–98.2%) and of midazolam was 99.0% (97.7–100.2%). Lorazepam experienced modest degradation by 60 days (95.6% [91.6–99.5%]) and substantial degradation at 90 days (90.3% [85.2-95.4%]) and 120 days (86.5% [80.7–92.3%]). Mean MKT was 31.6°C (95%CI 27.1–36.1). Increasing MKT was associated with greater degradation of lorazepam, but not midazolam or diazepam. Conclusions Midazolam and diazepam experienced minimal degradation throughout 120 days of EMS deployment in high-heat environments. Lorazepam experienced significant degradation over 120 days and appeared especially sensitive to higher MKT exposure. PMID:24548058

  13. Emergency medical service (EMS): A unique flight environment

    NASA Technical Reports Server (NTRS)

    Shively, R. Jay

    1993-01-01

    The EMS flight environment is unique in today's aviation. The pilots must respond quickly to emergency events and often fly to landing zones where they have never been before . The time from initially receiving a call to being airborne can be as little as two to three minutes. Often the EMS pilot is the only aviation professional on site, they have no operations people or other pilots to aid them in making decisons. Further, since they are often flying to accident scenes, not airports, there is often complete weather and condition information. Therefore, the initial decision that the pilot must make, accepting or declining a flight, can become very difficult. The accident rate of EMS helicopters has been relatively high over the past years. NASA-Ames research center has taken several steps in an attempt to aid EMS pilots in their decision making and situational awareness. A preflight risk assessment system (SAFE) was developed to aid pilots in their decision making, and was tested at an EMS service. The resutls of the study were promising and a second version incorporating the lessons learned is under development. A second line of research was the development of a low cost electronic chart display (ECD). This is a digital map display to help pilots maintain geographical orientation. Another thrust was undertaken in conjunction with the Aviation Safety Reporting System (ASRS). This involved publicizing the ASRS to EMS pilots and personnel, and calling each of the reporters back to gather additional information. This paper will discuss these efforts and how they may positively impact the safety of EMS operations.

  14. Persistent topology for cryo-EM data analysis.

    PubMed

    Xia, Kelin; Wei, Guo-Wei

    2015-08-01

    In this work, we introduce persistent homology for the analysis of cryo-electron microscopy (cryo-EM) density maps. We identify the topological fingerprint or topological signature of noise, which is widespread in cryo-EM data. For low signal-to-noise ratio (SNR) volumetric data, intrinsic topological features of biomolecular structures are indistinguishable from noise. To remove noise, we employ geometric flows that are found to preserve the intrinsic topological fingerprints of cryo-EM structures and diminish the topological signature of noise. In particular, persistent homology enables us to visualize the gradual separation of the topological fingerprints of cryo-EM structures from those of noise during the denoising process, which gives rise to a practical procedure for prescribing a noise threshold to extract cryo-EM structure information from noise contaminated data after certain iterations of the geometric flow equation. To further demonstrate the utility of persistent homology for cryo-EM data analysis, we consider a microtubule intermediate structure Electron Microscopy Data (EMD 1129). Three helix models, an alpha-tubulin monomer model, an alpha-tubulin and beta-tubulin model, and an alpha-tubulin and beta-tubulin dimer model, are constructed to fit the cryo-EM data. The least square fitting leads to similarly high correlation coefficients, which indicates that structure determination via optimization is an ill-posed inverse problem. However, these models have dramatically different topological fingerprints. Especially, linkages or connectivities that discriminate one model from another, play little role in the traditional density fitting or optimization but are very sensitive and crucial to topological fingerprints. The intrinsic topological features of the microtubule data are identified after topological denoising. By a comparison of the topological fingerprints of the original data and those of three models, we found that the third model is

  15. Colloidal Oatmeal <em>(Avena Sativa)em> Improves Skin Barrier Through Multi-Therapy Activity.

    PubMed

    Ilnytska, Olha; Kaur, Simarna; Chon, Suhyoun; Reynertson, Kurt A; Nebus, Judith; Garay, Michelle; Mahmood, Khalid; Southall, Michael D

    2016-06-01

    Oats (Avena sativa) are a centuries-old topical treatment for a variety of skin barrier conditions, including dry skin, skin rashes, and eczema; however, few studies have investigated the actual mechanism of action for the skin barrier strengthening activity of colloidal oatmeal. Four extracts of colloidal oatmeal were prepared with various solvents and tested in vitro for skin barrier related gene expression and activity. Extracts of colloidal oatmeal were found to induce the expression of genes related to epidermal differentiation, tight junctions and lipid regulation in skin, and provide pH-buffering capacity. Colloidal oatmeal boosted the expression of multiple target genes related to skin barrier, and resulted in recovery of barrier damage in an in vitro model of atopic dermatitis. In addition, an investigator-blinded study was performed with 50 healthy female subjects who exhibited bilateral moderate to severe dry skin on their lower legs. Subjects were treated with a colloidal oatmeal skin protectant lotion. Clinically, the colloidal oatmeal lotion showed significant clinical improvements in skin dryness, moisturization, and barrier. Taken together, these results demonstrate that colloidal oatmeal can provide clinically effective benefits for dry and compromised skin by strengthening skin barrier.

    <em>J Drugs Dermatolem>. 2016;15(6):684-690. PMID:27272074

  16. Learning when to Hold'em and When to Fold'em: ERS's Budget Hold'em Game Facilitates the Budget Development Process in Memphis

    ERIC Educational Resources Information Center

    Education Resource Strategies, 2010

    2010-01-01

    If your school district is facing a budget issue, it might surprise you to learn that the solution might very well lie in a game of cards. That certainly was the case earlier this year for the city schools of Memphis, Tennessee. The game is called Budget Hold'em, and it was developed by Education Resource Strategies (ERS) of Watertown,…

  17. Topical Treatment With an Agent Disruptive to <em>P. acnesem> Biofilm Provides Positive Therapeutic Response: Results of a Randomized Clinical Trial.

    PubMed

    Bernhardt, Michael J; Myntti, Matthew F

    2016-06-01

    The traditional disease model of acne has been one of follicular plugging due to 'sticky epithelial cells' associated with increased sebum production with deep follicular anaerobic conditions favoring <em>P. acnesem>- generated inflammation. <em>P. acnesem> biofilms have been found more frequently in patients with acne than controls. Biofilms are genetically coded to create adhesion to the pilosebaceous unit followed by production of a mucopolysaccharide coating capable of binding to lipid surfaces. Traditional therapies for acne have involved mixtures of oral and topical antibiotics admixed with topical keratolytics and retinoids, which are aimed at traditional bacterial reduction as well as downregulating the inflammatory cascade. These approaches are limited by side effect and compliance/tolerability issues. As the <em>P. acnesem> biofilm may, in fact, be the instigator of this process, we studied the use of a topical agent designed to reduce the <em>P. acnesem> biofilm to see if reducing the biofilm would be therapeutically efficacious. We present data of a proprietary topical non-prescription agent with a novel pharmaco mechanism designed to attack the biofilm produced by <em>P. acnesem>. Our data shows a decrease of inflammatory lesions by 44% and non-inflammatory lesions by 32% after 12 weeks and also provided for a meaningful improvement in the quality of life of the patients in the study. These improvements were achieved with a product that was not associated with burning, chafing, irritation, or erythema, which can be seen with topical treatments. It is apparent from this study that by addressing the biofilm which protects the <em>P. acnesem> bacteria through the use of the Acne Gel, the incidence of acne symptoms can be greatly reduced, while having no negative impacts on the patients' skin (ClinicalTrials.gov registry number NCT02404285).

    <em>J Drugs Dermatol. em>2016;15(6):677-683. PMID:27272073

  18. Refinement of Atomic Structures Against cryo-EM Maps.

    PubMed

    Murshudov, G N

    2016-01-01

    This review describes some of the methods for atomic structure refinement (fitting) against medium/high-resolution single-particle cryo-EM reconstructed maps. Some of the tools developed for macromolecular X-ray crystal structure analysis, especially those encapsulating prior chemical and structural information can be transferred directly for fitting into cryo-EM maps. However, despite the similarities, there are significant differences between data produced by these two techniques; therefore, different likelihood functions linking the data and model must be used in cryo-EM and crystallographic refinement. Although tools described in this review are mostly designed for medium/high-resolution maps, if maps have sufficiently good quality, then these tools can also be used at moderately low resolution, as shown in one example. In addition, the use of several popular crystallographic methods is strongly discouraged in cryo-EM refinement, such as 2Fo-Fc maps, solvent flattening, and feature-enhanced maps (FEMs) for visualization and model (re)building. Two problems in the cryo-EM field are overclaiming resolution and severe map oversharpening. Both of these should be avoided; if data of higher resolution than the signal are used, then overfitting of model parameters into the noise is unavoidable, and if maps are oversharpened, then at least parts of the maps might become very noisy and ultimately uninterpretable. Both of these may result in suboptimal and even misleading atomic models. PMID:27572731

  19. Active geophysical monitoring of hydrocarbon reservoirs using EM methods

    NASA Astrophysics Data System (ADS)

    Gribenko, A.; Black, N.; Zhdanov, M. S.

    2008-12-01

    Marine controlled-source electromagnetic (MCSEM) technology has been successfully established as an effective tool for offshore hydrocarbon (HC) exploration. In this paper we consider another application of the MCSEM method for HC reservoir monitoring. We demonstrate that EM methods can be successfully used for the monitoring of producing wells in connection with the enhanced recovery of hydrocarbons. We have developed a new powerful EM modeling technique based on the integral equation method with an inhomogeneous background conductivity (IE IBC). This new method and the corresponding computer software make it possible to model the EM response over a realistic complex model of a sea-bottom HC reservoir. The numerical modeling results demonstrate that the MCSEM method has the ability to map changes in resistivity caused by the production of hydrocarbons over time. In addition, the EM data help to visualize the changes in the location of the oil-water contact within the reservoir. This result opens the possibility for practical application of the EM method in HC reservoir monitoring.

  20. Application of the EM algorithm to radiographic images.

    PubMed

    Brailean, J C; Little, D; Giger, M L; Chen, C T; Sullivan, B J

    1992-01-01

    The expectation maximization (EM) algorithm has received considerable attention in the area of positron emitted tomography (PET) as a restoration and reconstruction technique. In this paper, the restoration capabilities of the EM algorithm when applied to radiographic images is investigated. This application does not involve reconstruction. The performance of the EM algorithm is quantitatively evaluated using a "perceived" signal-to-noise ratio (SNR) as the image quality metric. This perceived SNR is based on statistical decision theory and includes both the observer's visual response function and a noise component internal to the eye-brain system. For a variety of processing parameters, the relative SNR (ratio of the processed SNR to the original SNR) is calculated and used as a metric to compare quantitatively the effects of the EM algorithm with two other image enhancement techniques: global contrast enhancement (windowing) and unsharp mask filtering. The results suggest that the EM algorithm's performance is superior when compared to unsharp mask filtering and global contrast enhancement for radiographic images which contain objects smaller than 4 mm. PMID:1435595

  1. Breaking Cryo-EM Resolution Barriers to Facilitate Drug Discovery.

    PubMed

    Merk, Alan; Bartesaghi, Alberto; Banerjee, Soojay; Falconieri, Veronica; Rao, Prashant; Davis, Mindy I; Pragani, Rajan; Boxer, Matthew B; Earl, Lesley A; Milne, Jacqueline L S; Subramaniam, Sriram

    2016-06-16

    Recent advances in single-particle cryoelecton microscopy (cryo-EM) are enabling generation of numerous near-atomic resolution structures for well-ordered protein complexes with sizes ≥ ∼200 kDa. Whether cryo-EM methods are equally useful for high-resolution structural analysis of smaller, dynamic protein complexes such as those involved in cellular metabolism remains an important question. Here, we present 3.8 Å resolution cryo-EM structures of the cancer target isocitrate dehydrogenase (93 kDa) and identify the nature of conformational changes induced by binding of the allosteric small-molecule inhibitor ML309. We also report 2.8-Å- and 1.8-Å-resolution structures of lactate dehydrogenase (145 kDa) and glutamate dehydrogenase (334 kDa), respectively. With these results, two perceived barriers in single-particle cryo-EM are overcome: (1) crossing 2 Å resolution and (2) obtaining structures of proteins with sizes < 100 kDa, demonstrating that cryo-EM can be used to investigate a broad spectrum of drug-target interactions and dynamic conformational states. PMID:27238019

  2. International Space Station (ISS) Emergency Mask (EM) Development

    NASA Technical Reports Server (NTRS)

    Toon, Katherine P.; Hahn, Jeffrey; Fowler, Michael; Young, Kevin

    2011-01-01

    The Emergency Mask (EM) is considered a secondary response emergency Personal Protective Equipment (PPE) designed to provide respiratory protection to the International Space Station (ISS) crewmembers in response to a post-fire event or ammonia leak. The EM is planned to be delivered to ISS in 2012 to replace the current air purifying respirator (APR) onboard ISS called the Ammonia Respirator (AR). The EM is a one ]size ]fits ]all model designed to fit any size crewmember, unlike the APR on ISS, and uses either two Fire Cartridges (FCs) or two Commercial Off-the-Shelf (COTS) 3M(Trademark). Ammonia Cartridges (ACs) to provide the crew with a minimum of 8 hours of respiratory protection with appropriate cartridge swap ]out. The EM is designed for a single exposure event, for either post ]fire or ammonia, and is a passive device that cannot help crewmembers who cannot breathe on their own. The EM fs primary and only seal is around the wearer fs neck to prevent a crewmember from inhaling contaminants. During the development of the ISS Emergency Mask, several design challenges were faced that focused around manufacturing a leak free mask. The description of those challenges are broadly discussed but focuses on one key design challenge area: bonding EPDM gasket material to Gore(Registered Trademark) fabric hood.

  3. A Computerized Evaluation Methodology for Pre-Hospital EMS Cardiac Care

    PubMed Central

    Nagurney, Frank K.

    1980-01-01

    The computerized application of cardiac care protocols for pre-hospital EMS care is presented. The program logic is reviewed and an example of its application is provided. Uses of the results of the program in EMS management are suggested.

  4. EMS Stretcher “Misadventures” in a Large, Urban EMS System: A Descriptive Analysis of Contributing Factors and Resultant Injuries

    PubMed Central

    Goodloe, Jeffrey M.; Crowder, Christopher J.; Arthur, Annette O.; Thomas, Stephen H.

    2012-01-01

    Purpose. There is a paucity of data regarding EMS stretcher-operation-related injuries. This study describes and analyzes characteristics associated with undesirable stretcher operations, with or without resultant injury in a large, urban EMS agency. Methods. In the study agency, all stretcher-related “misadventures” are required to be documented, regardless of whether injury results. All stretcher-related reports between July 1, 2009 and June 30, 2010 were queried in retrospective analysis, avoiding Hawthorne effect in stretcher operations. Results. During the year studied, 129,110 patients were transported. 23 stretcher incidents were reported (0.16 per 1,000 transports). No patient injury occurred. Four EMS providers sustained minor injuries. Among contributing aspects, the most common involved operations surrounding the stretcher-ambulance safety latch, 14/23 (60.9%). From a personnel injury prevention perspective, there exists a significant relationship between combative patients and crew injury related to stretcher operation, Fisher's exact test 0.048. Conclusions. In this large, urban EMS system, the incidence of injury related to stretcher operations in the one-year study period is markedly low, with few personnel injuries and no patient injuries incurred. Safety for EMS personnel and patients could be advanced by educational initiatives that highlight specific events and conditions contributing to stretcher-related adverse events. PMID:22606379

  5. Recent technical advancements enabled atomic resolution CryoEM

    NASA Astrophysics Data System (ADS)

    Xueming, Li

    2016-01-01

    With recent breakthroughs in camera and image processing technologies single-particle electron cryo-microscopy (CryoEM) has suddenly gained the attention of structural biologists as a powerful tool able to solve the atomic structures of biological complexes and assemblies. Compared with x-ray crystallography, CryoEM can be applied to partially flexible structures in solution and without the necessity of crystallization, which is especially important for large complexes and assemblies. This review briefly explains several key bottlenecks for atomic resolution CryoEM, and describes the corresponding solutions for these bottlenecks based on the recent technical advancements. The review also aims to provide an overview about the technical differences between its applications in biology and those in material science. Project supported by Tsinghua-Peking Joint Center for Life Sciences, China.

  6. Virus particle dynamics derived from CryoEM studies.

    PubMed

    Doerschuk, Peter C; Gong, Yunye; Xu, Nan; Domitrovic, Tatiana; Johnson, John E

    2016-06-01

    The direct electron detector has revolutionized electron cryo-microscopy (CryoEM). Icosahedral virus structures are routinely produced at 4Å resolution or better and the approach has largely displaced virus crystallography, as it requires less material, less purity and often produces a structure more rapidly. Largely ignored in this new era of CryoEM is the dynamic information in the data sets that was not available in X-ray structures. Here we review an approach that captures the dynamic character of viruses displayed in the CryoEM ensemble of particles at the moment of freezing. We illustrate the approach with a simple model, briefly describe the details and provide a practical application to virus particle maturation. PMID:27085980

  7. Geospatial Analysis of Pediatric EMS Run Density and Endotracheal Intubation

    PubMed Central

    Hansen, Matthew; Loker, William; Warden, Craig

    2016-01-01

    Introduction The association between geographic factors, including transport distance, and pediatric emergency medical services (EMS) run clustering on out-of-hospital pediatric endotracheal intubation is unclear. The objective of this study was to determine if endotracheal intubation procedures are more likely to occur at greater distances from the hospital and near clusters of pediatric calls. Methods This was a retrospective observational study including all EMS runs for patients less than 18 years of age from 2008 to 2014 in a geographically large and diverse Oregon county that includes densely populated urban areas near Portland and remote rural areas. We geocoded scene addresses using the automated address locator created in the cloud-based mapping platform ArcGIS, supplemented with manual address geocoding for remaining cases. We then use the Getis-Ord Gi spatial statistic feature in ArcGIS to map statistically significant spatial clusters (hot spots) of pediatric EMS runs throughout the county. We then superimposed all intubation procedures performed during the study period on maps of pediatric EMS-run hot spots, pediatric population density, fire stations, and hospitals. We also performed multivariable logistic regression to determine if distance traveled to the hospital was associated with intubation after controlling for several confounding variables. Results We identified a total of 7,797 pediatric EMS runs during the study period and 38 endotracheal intubations. In univariate analysis we found that patients who were intubated were similar to those who were not in gender and whether or not they were transported to a children’s hospital. Intubated patients tended to be transported shorter distances and were older than non-intubated patients. Increased distance from the hospital was associated with reduced odds of intubation after controlling for age, sex, scene location, and trauma system entry status in a multivariate logistic regression. The

  8. Speaker verification using combined acoustic and EM sensor signal processing

    SciTech Connect

    Ng, L C; Gable, T J; Holzrichter, J F

    2000-11-10

    Low Power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference. This greatly enhances the quality and quantity of information for many speech related applications. See Holzrichter, Burnett, Ng, and Lea, J. Acoustic. SOC. Am . 103 ( 1) 622 (1998). By combining the Glottal-EM-Sensor (GEMS) with the Acoustic-signals, we've demonstrated an almost 10 fold reduction in error rates from a speaker verification system experiment under a moderate noisy environment (-10dB).

  9. Low Bandwidth Vocoding using EM Sensor and Acoustic Signal Processing

    SciTech Connect

    Ng, L C; Holzrichter, J F; Larson, P E

    2001-10-25

    Low-power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference [1]. By combining these data with the corresponding acoustic signal, we've demonstrated an almost 10-fold bandwidth reduction in speech compression, compared to a standard 2.4 kbps LPC10 protocol used in the STU-III (Secure Terminal Unit, third generation) telephone. This paper describes a potential EM sensor/acoustic based vocoder implementation.

  10. Developments in the EM-CCD camera for OGRE

    NASA Astrophysics Data System (ADS)

    Tutt, James H.; McEntaffer, Randall L.; DeRoo, Casey; Schultz, Ted; Miles, Drew M.; Zhang, William; Murray, Neil J.; Holland, Andrew D.; Cash, Webster; Rogers, Thomas; O'Dell, Steve; Gaskin, Jessica; Kolodziejczak, Jeff; Evagora, Anthony M.; Holland, Karen; Colebrook, David

    2014-07-01

    The Off-plane Grating Rocket Experiment (OGRE) is a sub-orbital rocket payload designed to advance the development of several emerging technologies for use on space missions. The payload consists of a high resolution soft X-ray spectrometer based around an optic made from precision cut and ground, single crystal silicon mirrors, a module of off-plane gratings and a camera array based around Electron Multiplying CCD (EM-CCD) technology. This paper gives an overview of OGRE with emphasis on the detector array; specifically this paper will address the reasons that EM-CCDs are the detector of choice and the advantages and disadvantages that this technology offers.

  11. Item Parameter Estimation via Marginal Maximum Likelihood and an EM Algorithm: A Didactic.

    ERIC Educational Resources Information Center

    Harwell, Michael R.; And Others

    1988-01-01

    The Bock and Aitkin Marginal Maximum Likelihood/EM (MML/EM) approach to item parameter estimation is an alternative to the classical joint maximum likelihood procedure of item response theory. This paper provides the essential mathematical details of a MML/EM solution and shows its use in obtaining consistent item parameter estimates. (TJH)

  12. 7 CFR 1945.35 - Special EM loan training.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS...) PROGRAM REGULATIONS (CONTINUED) EMERGENCY Disaster Assistance-General § 1945.35 Special EM loan training. (a) General. When it is evident that a large number of farmers were affected by a widespread...

  13. Reservoir characterization and steam flood monitoring with crosshole EM

    SciTech Connect

    Wilt, M.; Torres-Verdin, C.

    1995-06-01

    Crosshole electromagnetic (EM) imaging is applied to reservoir characterization and steam flood monitoring in a central California oil field. Steam was injected into three stacked eastward-dipping, unconsolidated oil sands within the upper 200 m. The steam plume is expected to develop as an ellipse aligned with the regional northwest-southeast strike. EM measurements were made from two fiberglass-cased observation wells straddling the steam injector on a northeast-southwest profile using the LLNL frequency domain crosshole EM system. Field data were collected before the initiation of a steam drive to map the distribution of the oil sands and then 6 and 12 months later to monitor the progress of the steam chest. Resistivity images derived from the EM data before steam injection clearly delineate the distribution and dipping structure on the target oil sands. Difference images, from data collected before and after steam flooding, show resistivity changes that indicate that the steam chest has developed only in the deeper oil sands although steam injection occurred in all three sand layers.

  14. 7 CFR 1945.20 - Making EM loans available.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 13 2010-01-01 2009-01-01 true Making EM loans available. 1945.20 Section 1945.20 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE SERVICE, RURAL UTILITIES SERVICE, AND FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE...

  15. Functionalized anatomical models for EM-neuron Interaction modeling.

    PubMed

    Neufeld, Esra; Cassará, Antonino Mario; Montanaro, Hazael; Kuster, Niels; Kainz, Wolfgang

    2016-06-21

    The understanding of interactions between electromagnetic (EM) fields and nerves are crucial in contexts ranging from therapeutic neurostimulation to low frequency EM exposure safety. To properly consider the impact of in vivo induced field inhomogeneity on non-linear neuronal dynamics, coupled EM-neuronal dynamics modeling is required. For that purpose, novel functionalized computable human phantoms have been developed. Their implementation and the systematic verification of the integrated anisotropic quasi-static EM solver and neuronal dynamics modeling functionality, based on the method of manufactured solutions and numerical reference data, is described. Electric and magnetic stimulation of the ulnar and sciatic nerve were modeled to help understanding a range of controversial issues related to the magnitude and optimal determination of strength-duration (SD) time constants. The results indicate the importance of considering the stimulation-specific inhomogeneous field distributions (especially at tissue interfaces), realistic models of non-linear neuronal dynamics, very short pulses, and suitable SD extrapolation models. These results and the functionalized computable phantom will influence and support the development of safe and effective neuroprosthetic devices and novel electroceuticals. Furthermore they will assist the evaluation of existing low frequency exposure standards for the entire population under all exposure conditions. PMID:27224508

  16. Functionalized anatomical models for EM-neuron Interaction modeling

    NASA Astrophysics Data System (ADS)

    Neufeld, Esra; Cassará, Antonino Mario; Montanaro, Hazael; Kuster, Niels; Kainz, Wolfgang

    2016-06-01

    The understanding of interactions between electromagnetic (EM) fields and nerves are crucial in contexts ranging from therapeutic neurostimulation to low frequency EM exposure safety. To properly consider the impact of in vivo induced field inhomogeneity on non-linear neuronal dynamics, coupled EM-neuronal dynamics modeling is required. For that purpose, novel functionalized computable human phantoms have been developed. Their implementation and the systematic verification of the integrated anisotropic quasi-static EM solver and neuronal dynamics modeling functionality, based on the method of manufactured solutions and numerical reference data, is described. Electric and magnetic stimulation of the ulnar and sciatic nerve were modeled to help understanding a range of controversial issues related to the magnitude and optimal determination of strength-duration (SD) time constants. The results indicate the importance of considering the stimulation-specific inhomogeneous field distributions (especially at tissue interfaces), realistic models of non-linear neuronal dynamics, very short pulses, and suitable SD extrapolation models. These results and the functionalized computable phantom will influence and support the development of safe and effective neuroprosthetic devices and novel electroceuticals. Furthermore they will assist the evaluation of existing low frequency exposure standards for the entire population under all exposure conditions.

  17. Texas Hold 'em Online Poker: A Further Examination

    ERIC Educational Resources Information Center

    Hopley, Anthony A. B.; Dempsey, Kevin; Nicki, Richard

    2012-01-01

    Playing Texas Hold 'em Online Poker (THOP) is on the rise. However, there is relatively little research examining factors that contribute to problem gambling in poker players. The aim of this study was to extend the research findings of Hopley and Nicki (2010). The negative mood states of depression, anxiety and stress were found to be linked to…

  18. Airborne EM for geothermal and hydrogeological mapping

    NASA Astrophysics Data System (ADS)

    Menghini, A.; Manzella, A.; Viezzoli, A.; Montanari, D.; Maggi, S.

    2012-12-01

    Within the "VIGOR" project, aimed at assessing the geothermal potential of four regions in southern Italy, Airborne EM data have been acquired, modeled and interpreted. The system deployed was SkyTEM, a time-domain helicopter electromagnetic system designed for hydrogeophysical, environmental and mineral investigations. The AEM data provide, after data acquisition, analysis, processing, and modeling, a distribution volume of electrical resistivity, spanning an investigation depth from ground surface of few hundred meters, depending on resistivity condition. Resistivity is an important physical parameter for geothermal investigation, since it proved to be very effective in mapping anomalies due to hydrothermal fluid circulation, which usually has high salt content and produces clayey alteration minerals. Since the project required, among other issues, to define geothermal resources at shallow level, it was decided to perform a test with an airborne electromagnetic geophysical survey, to verify the advantages offered by the system in covering large areas in a short time. The geophysical survey was carried out in Sicily, Italy, in late 2011, over two test sites named "Termini" and "Western Sicily". The two areas were chosen on different basis. "Termini" area is covered by extensive geological surveys, and was going to be investigated also by means of electrical tomography in its northern part. Since geological condition of Sicily, even at shallow depth, is very complex, this area provided a good place for defining the resistivity values of the main geological units outcropping in the region. "Termini" survey has been also an occasion to define relations between resistivity distribution, lithological units and thermal conductivity. The "Western Sicily" area cover the main thermal manifestations of western Sicily, and the research target was to establish whether they are characterized by common hydrogeological or tectonic features that could be mapped by resistivity

  19. Development of the Emergency Medical Services Role Identity Scale (EMS-RIS).

    PubMed

    Donnelly, Elizabeth A; Siebert, Darcy; Siebert, Carl

    2015-01-01

    This article describes the development and validation of the theoretically grounded Emergency Medical Services Role Identity Scale (EMS-RIS), which measures four domains of EMS role identity. The EMS-RIS was developed using a mixed methods approach. Key informants informed item development and the scale was validated using a representative probability sample of EMS personnel. Factor analyses revealed a conceptually consistent, four-factor solution with sound psychometric properties as well as evidence of convergent and discriminant validities. Social workers work with EMS professionals in crisis settings and as their counselors when they are distressed. The EMS-RIS provides useful information for the assessment of and intervention with distressed EMS professionals, as well as how role identity may influence occupational stress. PMID:25760489

  20. Nonlinear Smoothing and the EM Algorithm for Positive Integral Equations of the First Kind

    SciTech Connect

    Eggermont, P. P. B.

    1999-01-15

    We study a modification of the EMS algorithm in which each step of the EMS algorithm is preceded by a nonlinear smoothing step of the form Nf-exp(S*log f) , where S is the smoothing operator of the EMS algorithm. In the context of positive integral equations (a la positron emission tomography) the resulting algorithm is related to a convex minimization problem which always admits a unique smooth solution, in contrast to the unmodified maximum likelihood setup. The new algorithm has slightly stronger monotonicity properties than the original EM algorithm. This suggests that the modified EMS algorithm is actually an EM algorithm for the modified problem. The existence of a smooth solution to the modified maximum likelihood problem and the monotonicity together imply the strong convergence of the new algorithm. We also present some simulation results for the integral equation of stereology, which suggests that the new algorithm behaves roughly like the EMS algorithm.

  1. GPS computer navigators to shorten EMS response and transport times.

    PubMed

    Ota, F S; Muramatsu, R S; Yoshida, B H; Yamamoto, L G

    2001-05-01

    GPS (global positioning satellite system to determine one's position on earth) units have become inexpensive and compact. The purpose of this study is to assess the effectiveness of a GPS enhanced computer street map navigator to improve the ability of EMS drivers in an urban setting to locate their destination and shorten response times. For part I, residential addresses in the city were randomly selected from a telephone directory. Two driver/navigator teams were assigned to drive to the address adhering to speed limits. One team used a standard street map, whereas the other team used a GPS computer navigator. The travel time and distance of the runs were compared. For part II, the computer GPS navigator was placed on an ambulance to supplement their normal methods of navigation to find the address requesting EMS. After the run was completed, EMS providers were interviewed to determine their opinion of whether the GPS navigator was helpful. For part I the results showed that in the 29 initial test runs, comparing the GPS team versus the standard map team, the mean distances traveled were 8.7 versus 9.0 kilometers (not significant) and the mean travel times were 13.5 versus 14.6 minutes (P=.02), respectively. The GPS team arrived faster in 72% runs. For part II the results showed that most EMS providers surveyed noted that the GPS computer navigator enhanced their ability to find the destination and all EMS providers acknowledged that it would enhance their ability to find a destination in an area in which they were unfamiliar. These results suggest that a portable GPS computer navigator system is helpful and can enhance the ability of prehospital care providers to locate their destination. Because these units are accurate and inexpensive, GPS computer navigators may be a valuable tool in reducing pre-hospital transport times. PMID:11326345

  2. The B and Be States of the Star EM Cepheus

    NASA Astrophysics Data System (ADS)

    Kjurkchieva, Diana; Marchev, Dragomir; Sigut, T. A. A.; Dimitrov, Dinko

    2016-09-01

    We present 11 yr of high-resolution, spectroscopic observations for the star EM Cep. EM Cep switches between B and Be star states, as revealed by the level of Hα emission, but spends most of its time in the B star state. EM Cep has been considered to be an eclipsing, near-contact binary of nearly equal-mass B stars in order to reproduce regular photometric variations; however, this model is problematic due to the lack of any observed Doppler shift in the spectrum. Our observations confirm that there are no apparent Doppler shifts in the wide spectral lines Hα and He i λ6678 in either the B or Be star states. The profiles of He i λ6678 typically exhibited a filled-in absorption core, but we detected weak emission in this line during the highest Be state. Given the lack of observed Doppler shifts, we model EM Cep as an isolated Be star with a variable circumstellar disk. We can reproduce the observed Hα emission profiles over the 11 yr period reasonably well with disk masses on the order of 3{--}10× {10}-11 {M}* in the Be state with the circumstellar disk seen at an inclination of 78° to the line of sight. From a disk ejection episode in 2014, we estimate a mass-loss rate of ≈ 3× {10}-9 {M}ȯ {{yr}}-1. The derived disk density parameters are typical of those found for the classical Be stars. We therefore suggest that the EM Cep is a classical Be star and that its photometric variations are the result of β Cep or nonradial pulsations.

  3. Similarity-regulation of OS-EM for accelerated SPECT reconstruction.

    PubMed

    Vaissier, P E B; Beekman, F J; Goorden, M C

    2016-06-01

    Ordered subsets expectation maximization (OS-EM) is widely used to accelerate image reconstruction in single photon emission computed tomography (SPECT). Speedup of OS-EM over maximum likelihood expectation maximization (ML-EM) is close to the number of subsets used. Although a high number of subsets can shorten reconstruction times significantly, it can also cause severe image artifacts such as improper erasure of reconstructed activity if projections contain few counts. We recently showed that such artifacts can be prevented by using a count-regulated OS-EM (CR-OS-EM) algorithm which automatically adapts the number of subsets for each voxel based on the estimated number of counts that the voxel contributed to the projections. While CR-OS-EM reached high speed-up over ML-EM in high-activity regions of images, speed in low-activity regions could still be very slow. In this work we propose similarity-regulated OS-EM (SR-OS-EM) as a much faster alternative to CR-OS-EM. SR-OS-EM also automatically and locally adapts the number of subsets, but it uses a different criterion for subset regulation: the number of subsets that is used for updating an individual voxel depends on how similar the reconstruction algorithm would update the estimated activity in that voxel with different subsets. Reconstructions of an image quality phantom and in vivo scans show that SR-OS-EM retains all of the favorable properties of CR-OS-EM, while reconstruction speed can be up to an order of magnitude higher in low-activity regions. Moreover our results suggest that SR-OS-EM can be operated with identical reconstruction parameters (including the number of iterations) for a wide range of count levels, which can be an additional advantage from a user perspective since users would only have to post-filter an image to present it at an appropriate noise level. PMID:27206135

  4. Similarity-regulation of OS-EM for accelerated SPECT reconstruction

    NASA Astrophysics Data System (ADS)

    Vaissier, P. E. B.; Beekman, F. J.; Goorden, M. C.

    2016-06-01

    Ordered subsets expectation maximization (OS-EM) is widely used to accelerate image reconstruction in single photon emission computed tomography (SPECT). Speedup of OS-EM over maximum likelihood expectation maximization (ML-EM) is close to the number of subsets used. Although a high number of subsets can shorten reconstruction times significantly, it can also cause severe image artifacts such as improper erasure of reconstructed activity if projections contain few counts. We recently showed that such artifacts can be prevented by using a count-regulated OS-EM (CR-OS-EM) algorithm which automatically adapts the number of subsets for each voxel based on the estimated number of counts that the voxel contributed to the projections. While CR-OS-EM reached high speed-up over ML-EM in high-activity regions of images, speed in low-activity regions could still be very slow. In this work we propose similarity-regulated OS-EM (SR-OS-EM) as a much faster alternative to CR-OS-EM. SR-OS-EM also automatically and locally adapts the number of subsets, but it uses a different criterion for subset regulation: the number of subsets that is used for updating an individual voxel depends on how similar the reconstruction algorithm would update the estimated activity in that voxel with different subsets. Reconstructions of an image quality phantom and in vivo scans show that SR-OS-EM retains all of the favorable properties of CR-OS-EM, while reconstruction speed can be up to an order of magnitude higher in low-activity regions. Moreover our results suggest that SR-OS-EM can be operated with identical reconstruction parameters (including the number of iterations) for a wide range of count levels, which can be an additional advantage from a user perspective since users would only have to post-filter an image to present it at an appropriate noise level.

  5. Observação do abrilhantamento de limbo solar e de estruturas filamentares em 48 ghz utilizando a técnica de regularização adaptativa

    NASA Astrophysics Data System (ADS)

    Machado, W. R. S.; Mascarenhas, N.; Costa, J. E. R.; Silva, A. V. R.

    2003-08-01

    O radiotelescópio do Itapetinga tem sido utilizado em campanhas de observações de explosões solares gerando um grande número de mapas diários em 48 GHz como sub-produto destas observações. A resolução espacial do telescópio de 14m do Itapetinga nesta freqüência é de aproximadamente dois minutos de arco. Estruturas de interesse para análise da atmosfera solar quiescente tais como os filamentos e o anel de abrilhantamento do limbo são de dimensão angular moderada da ordem ou ligeiramente menores que a resolução do telescópio. É conhecido que a convolução da função de espalhamento do telescópio, PSF (padrão de ganho do feixe) borra as estruturas de dimensão angular abaixo do HPBW (largura a meia potência do feixe) e portanto é comum a busca por técnicas de restauração que eliminem pelo menos em parte este borramento. Estudamos a restauração destas radioimagens usando a técnica de regularização adaptativa e os resultados ressaltam estas estruturas espaciais de pequeno contraste. O algoritmo da regularização adaptativa faz uso de k imagens, chamadas protótipos, obtidas através da variação de parâmetros de um filtro de regularização. Para controle da qualidade da restauração utilizamos uma imagem de alta resolução espacial obtida na linha H-a e a PSF do Itapetinga para borrá-la. Pequenos desvios, entre a PSF utilizada para o borramento e a PSF utilizada na restauração, produziram alguns desvios notáveis na imagem restaurada porém a adição de ruído nas simulações de restauração foram mais influentes no cálculo da rugosidade da imagem e portanto mais limitante para a restauração. Apresentamos como nosso primeiro resultado uma imagem em 48 GHz com a presença clara do abrilhantamento de limbo que não estava evidente na imagem original e traços de estruturas filamentares, porém ainda sem grande evidência.

  6. Service Discovery Framework Supported by EM Algorithm and Bayesian Classifier

    NASA Astrophysics Data System (ADS)

    Peng, Yanbin

    Service oriented computing has become the main stream research field nowadays. Meanwhile, machine learning is a promising AI technology which can enhance the performance of traditional algorithm. Therefore, aiming at solving service discovery problem, this paper imports Bayesian classifier to web service discovery framework, which can improve service querying speed. In this framework, services in service library become training set of Bayesian classifier, service query becomes a testing sample. Service matchmaking process can be executed in related service class, which has fewer services, thus can save time. Due to don't know the class of service in training set, EM algorithm is used to estimate prior probability and likelihood functions. Experiment results show that the EM algorithm and Bayesian classifier supported method outperforms other methods in time complexity.

  7. Magen David Adom--the EMS in Israel.

    PubMed

    Ellis, Daniel Y; Sorene, Eliot

    2008-01-01

    Israel is a small country with a population of around 7 million. The sole EMS provider for Israel is Magen David Adom (MDA) (translated as 'Red Shield of David'). MDA also carries out the functions of a National Society (similar to the Red Cross) and provides all the blood and blood product services for the country. Nationwide, the organisation responds to over 1000 emergency calls a day and uses doctors, paramedics, emergency medical technicians and volunteers. Local geopolitics has meant that MDA has to be prepared for anything from everyday emergency calls to suicide bombings and regional wars. MDA also prides itself in being able to rapidly assemble and dispatch mobile aid teams to scenes of international disasters. Such a broad range of activities is unusual for a single EMS organisation. PMID:17767990

  8. Superconducting Electromagnetic Suspension (EMS) system for Grumman Maglev concept

    NASA Technical Reports Server (NTRS)

    Kalsi, Swarn S.

    1994-01-01

    The Grumman developed Electromagnetic Suspension (EMS) Maglev system has the following key characteristics: a large operating airgap--40 mm; levitation at all speeds; both high speed and low speed applications; no deleterious effects on SC coils at low vehicle speeds; low magnetic field at the SC coil--less than 0.35 T; no need to use non-magnetic/non-metallic rebar in the guideway structure; low magnetic field in passenger cabin--approximately 1 G; low forces on the SC coil; employs state-of-the-art NbTi wire; no need for an active magnet quench protection system; and lower weight than a magnet system with copper coils. The EMS Maglev described in this paper does not require development of any new technologies. The system could be built with the existing SC magnet technology.

  9. Environmental Restoration and Waste Management (EM) program: An introduction

    SciTech Connect

    Not Available

    1990-12-01

    This booklet introduces the reader to the mission and functions of a major new unit within the US Department of Energy (DOE): the Office of Environmental Restoration and Waste Management (EM). The Secretary of Energy established EM in November 1989, implementing a central purpose of DOE's first annual Environmental Restoration and Waste Management Five-Year Plan, which had appeared three months earlier. The contents of this booklet, and their arrangement, reflect the annual update of the Five-Year Plan. The Five-Year Plan supports DOE's strategy for meeting its 30-year compliance and cleanup goal. This strategy involves: focusing DOE's activities on eliminating or reducing known or recognized potential risks to worker and public health and the environment, containing or isolating, removing, or detoxifying onsite and offsite contamination, and developing technology to achieve DOE's environmental goals.

  10. Analysis of the Presence of Content about Astronomy in a Decade of the National High School Examination (1998-2008). (Spanish Title: Análisis de la Presencia de Contenidos de Astronomía em Uma Década del Examen Nacional de Enseñaza Secundária (1998-2008).) Análise da Presença de Conteúdos de Astronomia em Uma DÉcada do Exame Nacional do Ensino Médio (1998-2008)

    NASA Astrophysics Data System (ADS)

    Gomide, Hanny Angeles; Longhini, Marcos Daniel

    2011-07-01

    In this paper we analyzed the presence of contents of Astronomy in the National High School Examination (ENEM) in its first decade (1998-2008). We verified the number of questions addressing this topic that were present over the years, as well as the most recurrent subjects. We discussed the results from what is proposed by the official documents regarding the teaching of Astronomy in the Elementary and Secondary Education and we entertain future expectations about the presence of contents of this science in future official examinations. En este trabajo realizamos un análisis de la presencia de contenidos de Astronomía em las pruebas del Examen Nacional de Enseñanza Secundaria (ENEM) em su primera década de existência (1998-2008). Contabilizamos la cantidad de preguntas incluyendo este tema que estuvieron presentes en el transcurso de los años, así como los temas más recurrentes. Discutimos los resultados a partir de lo propuesto por los documentos oficiales en relación a la enseñanza de Astronomía en la Educación Básica y elaboramos algunos apuntes sobre futuras expectativas em relación a la presencia de contenidos de esta ciencia en examenes oficiales. No presente trabalho fizemos uma análise da presença de conteúdos de Astronomia nas provas do Exame Nacional do Ensino Médio (ENEM), em sua primeira década de existência (1998-2008). Verificamos a quantidade de questões envolvendo essa temática que estiveram presentes no decorrer dos anos, assim como os temas mais recorrentes. Discutimos os resultados a partir do que é proposto pelos documentos oficiais em relação ao ensino de Astronomia na Educação Básica e tecemos alguns apontamentos sobre a expectativa futura quanto à presença de conteúdos dessa ciência nesse exame oficial.

  11. Generalized single-particle cryo-EM--a historical perspective.

    PubMed

    Frank, Joachim

    2016-02-01

    This is a brief account of the earlier history of single-particle cryo-EM of biological molecules lacking internal symmetry, which goes back to the mid-seventies. The emphasis of this review is on the mathematical concepts and computational approaches. It is written as the field experiences a turning point in the wake of the introduction of digital cameras capable of single electron counting, and near-atomic resolution can be reached even for smaller molecules. PMID:26566976

  12. EMS-STARS: Emergency Medical Services "Superuser" Transport Associations: An Adult Retrospective Study.

    PubMed

    Hall, M Kennedy; Raven, Maria C; Hall, Jane; Yeh, Clement; Allen, Elaine; Rodriguez, Robert M; Tangherlini, Niels L; Sporer, Karl A; Brown, John F

    2015-01-01

    Abstract Objective. Emergency medical services (EMS) "superusers" -those who use EMS services at extremely high rates -have not been well characterized. Recent interest in the small group of individuals who account for a disproportionate share of health-care expenditures has led to research on frequent users of emergency departments and other health services, but little research has been done regarding those who use EMS services. To inform policy and intervention implementation, we undertook a descriptive analysis of EMS superusers in a large urban community. In this paper we compare EMS superusers to low, moderate, and high users to characterize factors contributing to EMS use. We also estimate the financial impact of EMS superusers. Methods. We conducted a retrospective cross-sectional study based on 1 year of data from an urban EMS system. Data for all EMS encounters with patients age ≥18 years were extracted from electronic records generated on scene by paramedics. We identified demographic and clinical variables associated with levels of EMS use. EMS users were characterized by the annual number of EMS encounters: low (1), moderate (2-4), high (5-14), and superusers (≥15). In addition, we performed a financial analysis using San Francisco Fire Department (SFFD) 2009 charge and reimbursement data. Results. A total of 31,462 adults generated 43,559 EMS ambulance encounters, which resulted in 39,107 transports (a 90% transport rate). Encounters for general medical reasons were common among moderate and high users and less frequent among superusers and low users, while alcohol use was exponentially correlated with encounter frequency. Superusers were significantly younger than moderate EMS users, and more likely to be male. The superuser group created a significantly higher financial burden/person than any other group, comprising 0.3% of the study population, but over 6% of annual EMS charges and reimbursements. Conclusions. In this retrospective study, adult

  13. The Genetics Panel of the NAS BEAR I Committee (1956): epistolary evidence suggests self-interest may have prompted an exaggeration of radiation risks that led to the adoption of the LNT cancer risk assessment model.

    PubMed

    Calabrese, Edward J

    2014-09-01

    This paper extends a series of historical papers which demonstrated that the linear-no-threshold (LNT) model for cancer risk assessment was founded on ideological-based scientific deceptions by key radiation genetics leaders. Based on an assessment of recently uncovered personal correspondence, it is shown that some members of the United States (US) National Academy of Sciences (NAS) Biological Effects of Atomic Radiation I (BEAR I) Genetics Panel were motivated by self-interest to exaggerate risks to promote their science and personal/professional agenda. Such activities have profound implications for public policy and may have had a significant impact on the adoption of the LNT model for cancer risk assessment. PMID:24993953

  14. Improving EM&V for Energy Efficiency Programs (Fact Sheet)

    SciTech Connect

    Not Available

    2012-07-01

    This fact sheet describes the objectives of the U.S. Department of Energy Uniform Methods Project to bring consistency to energy savings calculations in U.S. energy efficiency programs. The U.S. Department of Energy (DOE) is developing a framework and a set of protocols for determining gross energy savings from energy efficiency measures and programs. The protocols represent a refinement of the body of knowledge supporting energy efficiency evaluation, measurement, and verification (EM&V) activities. They have been written by technical experts within the field and reviewed by industry experts. Current EM&V practice allows for multiple methods for calculating energy savings. These methods were developed to meet the needs of energy efficiency program administrators and regulators. Although they served their original objectives well, they have resulted in inconsistent and incomparable savings results - even for identical measures. The goal of the Uniform Methods Project is to strengthen the credibility of energy savings determinations by improving EM&V, increasing the consistency and transparency of how energy savings are determined.

  15. The US DOE-EM International Program - 13004

    SciTech Connect

    Elmetti, Rosa R.; Han, Ana M.; Williams, Alice C.

    2013-07-01

    The U.S. Department of Energy (DOE) Office of Environmental Management (EM) conducts international collaboration activities in support of U.S. policies and objectives regarding the accelerated risk reduction and remediation of environmental legacy of the nations' nuclear weapons program and government sponsored nuclear energy research. The EM International Program supported out of the EM Office of the Associate Principal Deputy Assistant Secretary pursues collaborations with foreign government organizations, educational institutions and private industry to assist in identifying technologies and promote international collaborations that leverage resources and link international experience and expertise. In fiscal year (FY) 2012, the International Program awarded eight international collaborative projects for work scope spanning waste processing, groundwater and soil remediation, deactivation and decommissioning (D and D) and nuclear materials disposition initiatives to seven foreign organizations. Additionally, the International Program's scope and collaboration opportunities were expanded to include technical as well as non-technical areas. This paper will present an overview of the on-going tasks awarded in FY 2012 and an update of upcoming international activities and opportunities for expansion into FY 2013 and beyond. (authors)

  16. Electric Machines with Non-Radially Mounted Rectangular Permanent Magnets / Elektriskās Mašīnas Ar Prizmatiskiem Neradiāli Novietotiem Pastāvīgajiem Magnētiem

    NASA Astrophysics Data System (ADS)

    Levin, N.; Pugachev, V.; Dirba, J.; Lavrinovicha, L.

    2013-04-01

    The authors analyze the advantages and disadvantages of brushless synchronous electric machines with radially and non-radially mounted rectangular permanent magnets. The results show that the proposed nonradial mounting of permanent magnets considered in the paper, in several cases (e.g. multi-pole brushless generators with tooth windings of the armature) allows achievement of the following advantages: better technology of manufacturing the electric machine owing to simple packing of the stator winding in the stator open slots, which also increases the copper slot fillfactor; reduction in the mass-and-size of permanent magnets at least twice; significantly lower cost of the electric machine; and, finally, its greater specific power. Darbā tiek analizētas priekšrocības un trūkumi sinhronām bezkontaktu mašīnām ar radiāli un neradiāli novietotiem prizmatiskiem pastāvīgajiem magnētiem. Parādīts, ka vairākos gadījumos, piemēram, daudzpolu bezkontaktu sinhronajos ģeneratoros ar zobu tinumiem, neradiāls pastāvīgo magnētu izvietojums nodrošina vairākas priekšrocības: uzlabojas mašīnas izgatavošanas tehnoloģija, jo statora atvērtajās rievās vieglāk novietot tinumus un iespējams sasniegt augstāku rievas aizpildījuma koeficientu; samazinās pastāvīgo magnētu masa un izmaksas; palielinās mašīnas īpatnēja jauda.

  17. Volta phase plate cryo-EM of the small protein complex Prx3.

    PubMed

    Khoshouei, Maryam; Radjainia, Mazdak; Phillips, Amy J; Gerrard, Juliet A; Mitra, Alok K; Plitzko, Jürgen M; Baumeister, Wolfgang; Danev, Radostin

    2016-01-01

    Cryo-EM of large, macromolecular assemblies has seen a significant increase in the numbers of high-resolution structures since the arrival of direct electron detectors. However, sub-nanometre resolution cryo-EM structures are rare compared with crystal structure depositions, particularly for relatively small particles (<400 kDa). Here we demonstrate the benefits of Volta phase plates for single-particle analysis by time-efficient cryo-EM structure determination of 257 kDa human peroxiredoxin-3 dodecamers at 4.4 Å resolution. The Volta phase plate improves the applicability of cryo-EM for small molecules and accelerates structure determination. PMID:26817416

  18. Standard errors for EM estimates in generalized linear models with random effects.

    PubMed

    Friedl, H; Kauermann, G

    2000-09-01

    A procedure is derived for computing standard errors of EM estimates in generalized linear models with random effects. Quadrature formulas are used to approximate the integrals in the EM algorithm, where two different approaches are pursued, i.e., Gauss-Hermite quadrature in the case of Gaussian random effects and nonparametric maximum likelihood estimation for an unspecified random effect distribution. An approximation of the expected Fisher information matrix is derived from an expansion of the EM estimating equations. This allows for inferential arguments based on EM estimates, as demonstrated by an example and simulations. PMID:10985213

  19. Modeling of MHD edge containment in strip casting with ELEKTRA and CaPS-EM codes

    SciTech Connect

    Chang, F. C.

    2000-01-12

    This paper presents modeling studies of magnetohydrodynamics analysis in twin-roll casting. Argonne National Laboratory (ANL) and ISPAT Inland Inc. (Inland), formerly Inland Steel Co., have worked together to develop a three-dimensional (3-D) computer model that can predict eddy currents, fluid flows, and liquid metal containment of an electromagnetic (EM) edge containment device. The model was verified by comparing predictions with experimental results of liquid metal containment and fluid flow in EM edge dams (EMDs) that were designed at Inland for twin-roll casting. This mathematical model can significantly shorten casting research on the use of EM fields for liquid metal containment and control. The model can optimize the EMD design so it is suitable for application, and minimize expensive time-consuming full-scale testing. Numerical simulation was performed by coupling a 3-D finite-element EM code (ELEKTRA) and a 3-D finite-difference fluids code (CaPS-EM) to solve heat transfer, fluid flow, and turbulence transport in a casting process that involves EM fields. ELEKTRA can predict the eddy-current distribution and the EM forces in complex geometries. CaPS-EM can model fluid flows with free surfaces. The computed 3-D magnetic fields and induced eddy currents in ELEKTRA are used as input to temperature- and flow-field computations in CaPS-EM. Results of the numerical simulation compared well with measurements obtained from both static and dynamic tests.

  20. Volta phase plate cryo-EM of the small protein complex Prx3

    NASA Astrophysics Data System (ADS)

    Khoshouei, Maryam; Radjainia, Mazdak; Phillips, Amy J.; Gerrard, Juliet A.; Mitra, Alok K.; Plitzko, Jürgen M.; Baumeister, Wolfgang; Danev, Radostin

    2016-01-01

    Cryo-EM of large, macromolecular assemblies has seen a significant increase in the numbers of high-resolution structures since the arrival of direct electron detectors. However, sub-nanometre resolution cryo-EM structures are rare compared with crystal structure depositions, particularly for relatively small particles (<400 kDa). Here we demonstrate the benefits of Volta phase plates for single-particle analysis by time-efficient cryo-EM structure determination of 257 kDa human peroxiredoxin-3 dodecamers at 4.4 Å resolution. The Volta phase plate improves the applicability of cryo-EM for small molecules and accelerates structure determination.

  1. Covariance Matrix Estimation for the Cryo-EM Heterogeneity Problem*

    PubMed Central

    Katsevich, E.; Katsevich, A.; Singer, A.

    2015-01-01

    In cryo-electron microscopy (cryo-EM), a microscope generates a top view of a sample of randomly oriented copies of a molecule. The problem of single particle reconstruction (SPR) from cryo-EM is to use the resulting set of noisy two-dimensional projection images taken at unknown directions to reconstruct the three-dimensional (3D) structure of the molecule. In some situations, the molecule under examination exhibits structural variability, which poses a fundamental challenge in SPR. The heterogeneity problem is the task of mapping the space of conformational states of a molecule. It has been previously suggested that the leading eigenvectors of the covariance matrix of the 3D molecules can be used to solve the heterogeneity problem. Estimating the covariance matrix is challenging, since only projections of the molecules are observed, but not the molecules themselves. In this paper, we formulate a general problem of covariance estimation from noisy projections of samples. This problem has intimate connections with matrix completion problems and high-dimensional principal component analysis. We propose an estimator and prove its consistency. When there are finitely many heterogeneity classes, the spectrum of the estimated covariance matrix reveals the number of classes. The estimator can be found as the solution to a certain linear system. In the cryo-EM case, the linear operator to be inverted, which we term the projection covariance transform, is an important object in covariance estimation for tomographic problems involving structural variation. Inverting it involves applying a filter akin to the ramp filter in tomography. We design a basis in which this linear operator is sparse and thus can be tractably inverted despite its large size. We demonstrate via numerical experiments on synthetic datasets the robustness of our algorithm to high levels of noise. PMID:25699132

  2. Perda de massa em ventos empoeirados de estrelas supergigantes

    NASA Astrophysics Data System (ADS)

    Vidotto, A. A.; Jatenco-Pereira, V.

    2003-08-01

    Em praticamente todas as regiões do diagrama HR, as estrelas apresentam evidências observacionais de perda de massa. Na literatura, pode-se encontrar trabalhos que tratam tanto do diagnóstico da perda de massa como da construção de modelos que visam explicá-la. O amortecimento de ondas Alfvén tem sido utilizado como mecanismo de aceleração de ventos homogêneos. Entretanto, sabe-se que os envelopes de estrelas frias contêm grãos sólidos e moléculas. Com o intuito de estudar a interação entre as ondas Alfvén e a poeira e a sua conseqüência na aceleração do vento estelar, Falceta-Gonçalves & Jatenco-Pereira (2002) desenvolveram um modelo de perda de massa para estrelas supergigantes. Neste trabalho, apresentamos um estudo do modelo acima proposto para avaliar a dependência da taxa de perda de massa com alguns parâmetros iniciais como, por exemplo, a densidade r0, o campo magnético B0, o comprimento de amortecimento da onda L0, seu fluxo f0, entre outros. Sendo assim, aumentando f0 de 10% a partir de valores de referência, vimos que aumenta consideravelmente, enquanto que um aumento de mesmo valor em r0, B0 e L0 acarreta uma diminuição em .

  3. EM-21 Retrieval Knowledge Center: Waste Retrieval Challenges

    SciTech Connect

    Fellinger, Andrew P.; Rinker, Michael W.; Berglin, Eric J.; Minichan, Richard L.; Poirier, Micheal R.; Gauglitz, Phillip A.; Martin, Bruce A.; Hatchell, Brian K.; Saldivar, Eloy; Mullen, O Dennis; Chapman, Noel F.; Wells, Beric E.; Gibbons, Peter W.

    2009-04-10

    EM-21 is the Waste Processing Division of the Office of Engineering and Technology, within the U.S. Department of Energy’s (DOE) Office of Environmental Management (EM). In August of 2008, EM-21 began an initiative to develop a Retrieval Knowledge Center (RKC) to provide the DOE, high level waste retrieval operators, and technology developers with centralized and focused location to share knowledge and expertise that will be used to address retrieval challenges across the DOE complex. The RKC is also designed to facilitate information sharing across the DOE Waste Site Complex through workshops, and a searchable database of waste retrieval technology information. The database may be used to research effective technology approaches for specific retrieval tasks and to take advantage of the lessons learned from previous operations. It is also expected to be effective for remaining current with state-of-the-art of retrieval technologies and ongoing development within the DOE Complex. To encourage collaboration of DOE sites with waste retrieval issues, the RKC team is co-led by the Savannah River National Laboratory (SRNL) and the Pacific Northwest National Laboratory (PNNL). Two RKC workshops were held in the Fall of 2008. The purpose of these workshops was to define top level waste retrieval functional areas, exchange lessons learned, and develop a path forward to support a strategic business plan focused on technology needs for retrieval. The primary participants involved in these workshops included retrieval personnel and laboratory staff that are associated with Hanford and Savannah River Sites since the majority of remaining DOE waste tanks are located at these sites. This report summarizes and documents the results of the initial RKC workshops. Technology challenges identified from these workshops and presented here are expected to be a key component to defining future RKC-directed tasks designed to facilitate tank waste retrieval solutions.

  4. Single-particle cryo-EM at crystallographic resolution

    PubMed Central

    Cheng, Yifan

    2015-01-01

    Until only a few years ago, single-particle electron cryo-microscopy (cryo-EM) was usually not the first choice for many structural biologists due to its limited resolution in the range of nanometer to subnanometer. Now, this method rivals X-ray crystallography in terms of resolution and can be used to determine atomic structures of macromolecules that are either refractory to crystallization or difficult to crystallize in specific functional states. In this review, I discuss the recent breakthroughs in both hardware and software that transformed cryo-microscopy, enabling understanding of complex biomolecules and their functions at atomic level. PMID:25910205

  5. A compulsator driven rapid-fire EM-gun

    SciTech Connect

    Pratap, S.B.; Bird, W.L.

    1984-03-01

    A compulsator-driven railgun is an attractive alternative to the homopolar generator-inductor-switch configuration, especially for repetitive duty. A conceptual design of a rapid-fire EM-gun system is presented. The generator is sized to accelerate a 0.08-kg projectile to 2 to 3 km/s at a 60 pulse-per-second repetition rate. Initial design parameters are discussed, and example current and velocity waveforms are given. The generator is discharged at the proper phase angle to provide a current zero just as the projectile exits the muzzle of the railgun.

  6. EM Modelling of RF Propagation Through Plasma Plumes

    NASA Astrophysics Data System (ADS)

    Pandolfo, L.; Bandinelli, M.; Araque Quijano, J. L.; Vecchi, G.; Pawlak, H.; Marliani, F.

    2012-05-01

    Electric propulsion is a commercially attractive solution for attitude and position control of geostationary satellites. Hall-effect ion thrusters generate a localized plasma flow in the surrounding of the satellite, whose impact on the communication system needs to be qualitatively and quantitatively assessed. An electromagnetic modelling tool has been developed and integrated into the Antenna Design Framework- ElectroMagnetic Satellite (ADF-EMS). The system is able to guide the user from the plume definition phases through plume installation and simulation. A validation activity has been carried out and the system has been applied to the plume modulation analysis of SGEO/Hispasat mission.

  7. Developing State and National Evaluation Infrastructures- Guidance for the Challenges and Opportunities of EM&V

    SciTech Connect

    Schiller, Steven R.; Goldman, Charles A.

    2011-06-24

    Evaluating the impacts and effectiveness of energy efficiency programs is likely to become increasingly important for state policymakers and program administrators given legislative mandates and regulatory goals and increasing reliance on energy efficiency as a resource. In this paper, we summarize three activities that the authors have conducted that highlight the expanded role of evaluation, measurement and verification (EM&V): a study that identified and analyzed challenges in improving and scaling up EM&V activities; a scoping study that identified issues involved in developing a national efficiency EM&V standard; and lessons learned from providing technical assistance on EM&V issues to states that are ramping up energy efficiency programs. The lessons learned are summarized in 13 EM&V issues that policy makers should address in each jurisdiction and which are listed and briefly described. The paper also discusses how improving the effectiveness and reliability of EM&V will require additional capacity building, better access to existing EM&V resources, new methods to address emerging issues and technologies, and perhaps foundational documents and approaches to improving the credibility and cross jurisdictional comparability of efficiency investments. Two of the potential foundational documents discussed are a national EM&V standard or resource guide and regional deemed savings and algorithm databases.

  8. EMS Instructor Training Program. National Standard Curriculum. Instructor Guide. Student Guide.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    This guide for teaching a course to prepare emergency medical service (EMS) trainers focuses on the skills necessary to present any of the Department of Transportation (DOT), National Highway Traffic Safety Administration (NHTSA) EMS courses. Course topics are as follows: (1) introduction; (2) instructor roles and responsibilities; (3) legal…

  9. Method for evaluating compatibility of commercial electromagnetic (EM) microsensor tracking systems with surgical and imaging tables

    NASA Astrophysics Data System (ADS)

    Nafis, Christopher; Jensen, Vern; von Jako, Ron

    2008-03-01

    Electromagnetic (EM) tracking systems have been successfully used for Surgical Navigation in ENT, cranial, and spine applications for several years. Catheter sized micro EM sensors have also been used in tightly controlled cardiac mapping and pulmonary applications. EM systems have the benefit over optical navigation systems of not requiring a line-of-sight between devices. Ferrous metals or conductive materials that are transient within the EM working volume may impact tracking performance. Effective methods for detecting and reporting EM field distortions are generally well known. Distortion compensation can be achieved for objects that have a static spatial relationship to a tracking sensor. New commercially available micro EM tracking systems offer opportunities for expanded image-guided navigation procedures. It is important to know and understand how well these systems perform with different surgical tables and ancillary equipment. By their design and intended use, micro EM sensors will be located at the distal tip of tracked devices and therefore be in closer proximity to the tables. Our goal was to define a simple and portable process that could be used to estimate the EM tracker accuracy, and to vet a large number of popular general surgery and imaging tables that are used in the United States and abroad.

  10. Covariance Structure Model Fit Testing under Missing Data: An Application of the Supplemented EM Algorithm

    ERIC Educational Resources Information Center

    Cai, Li; Lee, Taehun

    2009-01-01

    We apply the Supplemented EM algorithm (Meng & Rubin, 1991) to address a chronic problem with the "two-stage" fitting of covariance structure models in the presence of ignorable missing data: the lack of an asymptotically chi-square distributed goodness-of-fit statistic. We show that the Supplemented EM algorithm provides a convenient…

  11. The Relationship between the Bock-Aitkin Procedure and the EM Algorithm for IRT Model Estimation.

    ERIC Educational Resources Information Center

    Hsu, Yaowen; Ackerman, Terry A.; Fan, Meichu

    It has previously been shown that the Bock-Aitkin procedure (R. Bock and M. Aitkin, 1981) is an instance of the EM algorithm when trying to find the marginal maximum likelihood estimate for a discrete latent ability variable (latent trait). In this paper, it is shown that the Bock-Aitkin procedure is a numerical implementation of the EM algorithm…

  12. Global Convergence of the EM Algorithm for Unconstrained Latent Variable Models with Categorical Indicators

    ERIC Educational Resources Information Center

    Weissman, Alexander

    2013-01-01

    Convergence of the expectation-maximization (EM) algorithm to a global optimum of the marginal log likelihood function for unconstrained latent variable models with categorical indicators is presented. The sufficient conditions under which global convergence of the EM algorithm is attainable are provided in an information-theoretic context by…

  13. Signaling of cell fate determination by the TPD1 small protein and EMS1 receptor kinase

    PubMed Central

    Jia, Gengxiang; Liu, Xiaodong; Owen, Heather A.; Zhao, Dazhong

    2008-01-01

    Sexual reproduction requires the specification of cells with distinct fates in plants and animals. The EMS1 (also known as EXS) leucine-rich repeat receptor-like kinase (LRR-RLK) and TPD1 small protein play key roles in regulating somatic and reproductive cell fate determination in Arabidopsis anthers. Here, we show that ectopic expression of TPD1 causes abnormal differentiation of somatic and reproductive cells in anthers. In addition, ectopic TPD1 activity requires functional EMS1. Yeast two-hybrid, pull-down, and coimmunoprecipitation analyses further demonstrate that TPD1 interacts with EMS1 in vitro and in vivo. Moreover, TPD1 induces EMS1 phosphorylation in planta. Thus, our results suggest that TPD1 serves as a ligand for the EMS1 receptor kinase to signal cell fate determination during plant sexual reproduction. PMID:18250314

  14. A Generalized Fast Frequency Sweep Algorithm for Coupled Circuit-EM Simulations

    SciTech Connect

    Rockway, J D; Champagne, N J; Sharpe, R M; Fasenfest, B

    2004-01-14

    Frequency domain techniques are popular for analyzing electromagnetics (EM) and coupled circuit-EM problems. These techniques, such as the method of moments (MoM) and the finite element method (FEM), are used to determine the response of the EM portion of the problem at a single frequency. Since only one frequency is solved at a time, it may take a long time to calculate the parameters for wideband devices. In this paper, a fast frequency sweep based on the Asymptotic Wave Expansion (AWE) method is developed and applied to generalized mixed circuit-EM problems. The AWE method, which was originally developed for lumped-load circuit simulations, has recently been shown to be effective at quasi-static and low frequency full-wave simulations. Here it is applied to a full-wave MoM solver, capable of solving for metals, dielectrics, and coupled circuit-EM problems.

  15. AVALIAÇÃO DA PRESENÇA DE ENDOSSIMBIONTES Cardinium em DIFERENTES ESPÉCIES DE ARTRÓPODES.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A presença de endossimbiontes do gênero Cardinium em alguns grupos de artrópodes foi recentemente relatada e relacionada com diversas alterações reprodutivas em seus hospedeiros, tais como feminilização de ácaros, partenogênese em parasitóides, incompatibilidade citoplasmática e aumento da fecundida...

  16. Aristarchus's <em>On the Sizes and Distances of the Sun and the Moonem>: Greek and Arabic Texts

    NASA Astrophysics Data System (ADS)

    Berggren, J. L.; Sidoli, N.

    2007-05-01

    In the 1920s, T. L. Heath pointed out that historians of mathematics have "given too little attention to Aristarchus". This is still true today. The Greek text of Aristarchus's On the Sizes and Distances of the Sun and the Moonem> has received little attention; the Arabic editions virtually none. Much of what this text has to tell us about ancient and medieval mathematics and the mathematical sciences has gone unnoticed. It should be taken as an important source for our understanding of the mathematical sciences of the early Hellenistic period.

  17. The EM fields in the Solid Generated by a Fault in a Porous Region

    NASA Astrophysics Data System (ADS)

    Ren, H.; Huang, Q.; Chen, X.

    2015-12-01

    Electrokinetic effect, as one of the most possible generation mechanisms of the seismo-electromagnetic phenomenons associated with natural earthquakes, has interested many researchers. Besides, it is also considered as a potential tool for the water/oil exploration. Recently, we numerically investigated the electromagnetic (EM) fields due to the electrokinetic effect in mixed layered model. The mixed model comprises not only porous layers but also solid layers. We firstly tested a two-layer mixed model. The numerical results show that, in addition to the radiation EM fields, another kind of evanescent EM fields can be generated by the seismic waves arriving at the interface with incident angles greater the critical angle. The evanescent EM fields decay faster than the radiation EM fields when getting away from the interface. For the seismic frequency band, the evanescent EM fields in the solid are still measurable at a distance of, e.g., 2km to the interface. We then tested a eight-layer mixed model. The top and bottom layers are solid and the other layers are porous. A finite fault of 20x10km is located in the porous region. The focal depth is 8km. The applied source time function is a ramp fuction with an arise time of 0.8s. Point stacking method was used to compute the wave-fields caused by the finite fault. Our nuemrical results show that, this model can generate the EM fields before the arrival of seismic waves as well as the residual EM fields. Both the two kinds of EM fields have been observed in field observations. There is a possibility that the anomalous EM activities before big earthquakes may be caused by the fluid flow in the shallow Earth as a result of the stress changes.

  18. Review of selected oceanic EM/EO scattering problems

    NASA Astrophysics Data System (ADS)

    Haller, Merrick C.

    2010-02-01

    Electromagnetic and electro-optical (EM/EO) propagation and scattering in the ocean is of interest for a wide range of science problems. For example, the biological productivity of ocean waters through photochemical processes is governed by the vertical attenuation of solar radiation. Also, EO scattering theory is the primary basis for determining biogeochemical parameters (e.g. phytoplankton, suspended sediments, and dissolved matter) from the water leaving optical radiance. In addition, EO scattering from suspended sediments and bubbles is the limiting factor for active lidar systems used to map the sea bottom. This work will review specific applications of EO/EM scattering theory with regard to the influence of bubbles and droplets on remote sensing in the nearshore ocean. The current state of understanding concerning models and applications for optical scattering from bubbles in the water column as well as microwave scattering from water droplets produced by breaking waves at the ocean surface will be discussed as well as future research directions.

  19. The Search for Gravitational Wave EM Counterparts with Swift

    NASA Astrophysics Data System (ADS)

    Kennea, Jamie; Evans, Phil; Swift GW follow-up Team

    2016-04-01

    We present the plan to search for electromagnetic counterparts of Gravitational Waves (GWs) discovered during the current and upcoming runs of the LIGO and Virgo detectors. As we enter a period where the sensitivity of the current generation of GW detectors approaches a high probability of the first detection of a real GW signal, confirmation of the reality of these triggers will be greatly improved if an EM counterpart can be found. Swift’s ability to rapidly respond to high priority target-of-opportunity observations, it’s multi-wavelength capabilities and low overhead observing make it a seemingly ideal follow-up facility. However comparing the size of the expected GW error regions with the fields of view of the Swift XRT and UVOT telescopes, we find that covering the large GW error regions would require a unreasonably large number of pointings. We present our method of meeting this challenge, by both reducing the problem using Galaxy targeting, and by operating Swift in an entirely new way in order to cover the still large number of fields needed to chase down the EM counterpart before it disappears.

  20. Chapter 19: HVAC Controls (DDC/EMS/BAS) Evaluation Protocol

    SciTech Connect

    Romberger, J.

    2014-11-01

    The HVAC Controls Evaluation Protocol is designed to address evaluation issues for direct digital controls/energy management systems/building automation systems (DDC/EMS/BAS) that are installed to control heating, ventilation, and air-conditioning (HVAC) equipment in commercial and institutional buildings. (This chapter refers to the DDC/EMS/BAS measure as HVAC controls.) This protocol may also be applicable to industrial facilities such as clean rooms and labs, which have either significant HVAC equipment or spaces requiring special environmental conditions. This protocol addresses only HVAC-related equipment and the energy savings estimation methods associated with installing such control systems as an energy efficiency measure. The affected equipment includes: Air-side equipment (air handlers, direct expansion systems, furnaces, other heating- and cooling-related devices, terminal air distribution equipment, and fans); Central plant equipment (chillers, cooling towers, boilers, and pumps). These controls may also operate or affect other end uses, such as lighting, domestic hot water, irrigation systems, and life safety systems such as fire alarms and other security systems. Considerable nonenergy benefits, such as maintenance scheduling, system component troubleshooting, equipment failure alarms, and increased equipment lifetime, may also be associated with these systems. When connected to building utility meters, these systems can also be valuable demand-limiting control tools. However, this protocol does not evaluate any of these additional capabilities and benefits.

  1. Contactless ultrasonic treatment of melts using EM induction

    NASA Astrophysics Data System (ADS)

    Bojarevics, V.; Djambazov, G.; Lebon, G. S. B.; Pericleous, K. A.

    2015-06-01

    Ultrasound Treatment (UT) is commonly used in light alloys during solidification to refine microstructure, or disperse immersed particles. A sonotrode probe introduced into the melt generates sound waves that are strong enough to produce cavitation of dissolved gases. The same method cannot be used in high temperature melts, or for highly reactive alloys, due to probe erosion and melt contamination. An alternative, contactless method of generating sound waves is proposed and investigated theoretically in this paper, using electromagnetic (EM) induction. In addition to strong vibration, the EM induction currents generate strong stirring in the melt that aids distribution of the UT effect to large volumes of material. In a typical application, the same induction coil surrounding the crucible used to melt the alloy may be adopted for UT with suitable frequency tuning. Alternatively - or in addition - a top coil may be used. For industrial use, instead of multiple sonotrodes as has been the practice in scaling up, modelling shows that one simply has to alter the coil geometry and current to suit. To reach sinusoidal pressure fluctuations suitable for cavitation it may be necessary to tune the induction coil frequency for resonance, given the crucible dimensions.

  2. The EM SSAB Annual Work Plan Process: Focusing Board Efforts and Resources - 13667

    SciTech Connect

    Young, Ralph

    2013-07-01

    One of the most daunting tasks for any new member of a local board of the Environmental Management Site Specific Advisory Board (EM SSAB) is to try to understand the scope of the clean-up activities going on at the site. In most cases, there are at least two or three major cleanup activities in progress as well as monitoring of past projects. When planning for future projects is added to the mix, the list of projects can be long. With the clean-up activities involving all major environmental media - air, water, soils, and groundwater, new EM SSAB members can find themselves totally overwhelmed and ineffective. Helping new members get over this initial hurdle is a major objective of EM and all local boards of the EM SSAB. Even as members start to understand the size and scope of the projects at a site, they can still be frustrated at the length of time it takes to see results and get projects completed. Many project and clean-up timelines for most of the sites go beyond 10 years, so it's not unusual for an EM SSAB member to see the completion of only 1 or 2 projects over the course of their 6-year term on the board. This paper explores the annual work planning process of the EM SSAB local boards, one tool that can be used to educate EM SSAB members into seeing the broader picture for the site. EM SSAB local work plans divide the site into projects focused on a specific environmental issue or media such as groundwater and/or waste disposal options. Projects are further broken down into smaller segments by highlighting major milestones. Using these metrics, local boards of the EM SSAB can start to quantify the effectiveness of the project in achieving the ultimate goal of site clean-up. These metrics can also trigger board advice and recommendations for EM. At the beginning of each fiscal year, the EM SSAB work plan provides a road map with quantifiable checkpoints for activities throughout the year. When the work plans are integrated with site-specific, enforceable

  3. High-gain 1.3  μm GaInNAs semiconductor optical amplifier with enhanced temperature stability for all-optical signal processing at 10  Gb/s.

    PubMed

    Fitsios, D; Giannoulis, G; Korpijärvi, V-M; Viheriälä, J; Laakso, A; Iliadis, N; Dris, S; Spyropoulou, M; Avramopoulos, H; Kanellos, G T; Pleros, N; Guina, M

    2015-01-01

    We report on the complete experimental evaluation of a GaInNAs/GaAs (dilute nitride) semiconductor optical amplifier that operates at 1.3 μm and exhibits 28 dB gain and a gain recovery time of 100 ps. Successful wavelength conversion operation is demonstrated using pseudorandom bit sequence 27-1 non-return-to-zero bit streams at 5 and 10  Gb/s, yielding error-free performance and showing feasibility for implementation in various signal processing functionalities. The operational credentials of the device are analyzed in various operational regimes, while its nonlinear performance is examined in terms of four-wave mixing. Moreover, characterization results reveal enhanced temperature stability with almost no gain variation around the 1320 nm region for a temperature range from 20°C to 50°C. The operational characteristics of the device, along with the cost and energy benefits of dilute nitride technology, make it very attractive for application in optical access networks and dense photonic integrated circuits. PMID:25967005

  4. Linear array implementation of the EM algorithm for PET image reconstruction

    SciTech Connect

    Rajan, K.; Patnaik, L.M.; Ramakrishna, J.

    1995-08-01

    The PET image reconstruction based on the EM algorithm has several attractive advantages over the conventional convolution back projection algorithms. However, the PET image reconstruction based on the EM algorithm is computationally burdensome for today`s single processor systems. In addition, a large memory is required for the storage of the image, projection data, and the probability matrix. Since the computations are easily divided into tasks executable in parallel, multiprocessor configurations are the ideal choice for fast execution of the EM algorithms. In tis study, the authors attempt to overcome these two problems by parallelizing the EM algorithm on a multiprocessor systems. The parallel EM algorithm on a linear array topology using the commercially available fast floating point digital signal processor (DSP) chips as the processing elements (PE`s) has been implemented. The performance of the EM algorithm on a 386/387 machine, IBM 6000 RISC workstation, and on the linear array system is discussed and compared. The results show that the computational speed performance of a linear array using 8 DSP chips as PE`s executing the EM image reconstruction algorithm is about 15.5 times better than that of the IBM 6000 RISC workstation. The novelty of the scheme is its simplicity. The linear array topology is expandable with a larger number of PE`s. The architecture is not dependant on the DSP chip chosen, and the substitution of the latest DSP chip is straightforward and could yield better speed performance.

  5. A new method for vitrifying samples for cryoEM.

    PubMed

    Razinkov, Ivan; Dandey, Venkata P; Wei, Hui; Zhang, Zhening; Melnekoff, David; Rice, William J; Wigge, Christoph; Potter, Clinton S; Carragher, Bridget

    2016-08-01

    Almost every aspect of cryo electron microscopy (cryoEM) has been automated over the last few decades. One of the challenges that remains to be addressed is the robust and reliable preparation of vitrified specimens of suitable ice thickness. We present results from a new device for preparing vitrified samples. The successful use of the device is coupled to a new "self-blotting" grid that we have developed to provide a method for spreading a sample to a thin film without the use of externally applied filter paper. This new approach has the advantage of using small amounts of protein material, resulting in large areas of ice of a well defined thickness containing evenly distributed single particles. We believe that these methods will in the future result in a system for vitrifying grids that is completely automated. PMID:27288865

  6. Speech articulator measurements using low power EM-wave sensors

    SciTech Connect

    Holzrichter, J.F.; Burnett, G.C.; Ng, L.C.; Lea, W.A.

    1998-01-01

    Very low power electromagnetic (EM) wave sensors are being used to measure speech articulator motions as speech is produced. Glottal tissue oscillations, jaw, tongue, soft palate, and other organs have been measured. Previously, microwave imaging (e.g., using radar sensors) appears not to have been considered for such monitoring. Glottal tissue movements detected by radar sensors correlate well with those obtained by established laboratory techniques, and have been used to estimate a voiced excitation function for speech processing applications. The noninvasive access, coupled with the small size, low power, and high resolution of these new sensors, permit promising research and development applications in speech production, communication disorders, speech recognition and related topics. {copyright} {ital 1998 Acoustical Society of America.}

  7. EM Properties of Magnetic Minerals at RADAR Frequencies

    NASA Technical Reports Server (NTRS)

    Stillman, D. E.; Olhoeft, G. R.

    2005-01-01

    Previous missions to Mars have revealed that Mars surface is magnetic at DC frequency. Does this highly magnetic surface layer attenuate RADAR energy as it does in certain locations on Earth? It has been suggested that the active magnetic mineral on Mars is titanomaghemite and/or titanomagnetite. When titanium is incorporated into a maghemite or magnetite crystal, the Curie temperature can be significantly reduced. Mars has a wide range of daily temperature fluctuations (303K - 143K), which could allow for daily passes through the Curie temperature. Hence, the global dust layer on Mars could experience widely varying magnetic properties as a function of temperature, more specifically being ferromagnetic at night and paramagnetic during the day. Measurements of EM properties of magnetic minerals were made versus frequency and temperature (300K- 180K). Magnetic minerals and Martian analog samples were gathered from a number of different locations on Earth.

  8. Balloting motion of SLEKE launch packages in EM railguns

    NASA Astrophysics Data System (ADS)

    Chu, Szu H.

    1993-01-01

    This paper reports some balloting motion computational results of the SLEKE (Sabot Launched Electric-gun Kinetic Energy) launch packages, which are in their early stage of development. The computation model considers the effects of the EM (Lorentz) propulsion force, friction, air resistance, gravity, elastic forces, and clearance between the launch package and the barrel. The axial, normal and yaw displacement, velocity and acceleration; friction; deformations and forces at the interfacing points are computed. The results of this study indicate that the balloting force for SLEKE launch packages is on the order of the air drag force and that a uniformly distributed power source would be more desirable than sharp pulse current for electromagnetic railguns.

  9. Detection of karst structures using airborne EM and VLF

    SciTech Connect

    Beard, L.P. Nyquist, J.E.; Carpenter, P.J.

    1994-12-31

    Through the combined use of multi-frequency helicopter electromagnetic and VLF data, it is possible to detect and delineate a wide variety of karst structures and possibly to assess their interconnectedness. Multi-frequency EM Can detect karst features if some element of the structure is conductive. This conductive aspect may derive from thick, moist soils in the depression commonly associated with a doline, from conductive fluids in the cavity, or from conductive sediments in the cavity if these occupy a significant portion of it. Multiple loop configurations may also increase the likelihood of detecting karst features. Preliminary evidence indicates total field VLF measurements may be able to detect interconnected karst pathways, so long as the pathways are water or sediment filled. Neither technique can effectively detect dry, resistive air-filled cavities.

  10. Integrated EM & Thermal Simulations with Upgraded VORPAL Software

    SciTech Connect

    D.N. Smithe, D. Karipides, P. Stoltz, G. Cheng, H. Wang

    2011-03-01

    Nuclear physics accelerators are powered by microwaves which must travel in waveguides between room-temperature sources and the cryogenic accelerator structures. The ohmic heat load from the microwaves is affected by the temperature-dependent surface resistance and in turn affects the cryogenic thermal conduction problem. Integrated EM & thermal analysis of this difficult non-linear problem is now possible with the VORPAL finite-difference time-domain simulation tool. We highlight thermal benchmarking work with a complex HOM feed-through geometry, done in collaboration with researchers at the Thomas Jefferson National Accelerator Laboratory, and discuss upcoming design studies with this emerging tool. This work is part of an effort to generalize the VORPAL framework to include generalized PDE capabilities, for wider multi-physics capabilities in the accelerator, vacuum electronics, plasma processing and fusion R&D fields, and we will also discuss user interface and algorithmic upgrades which facilitate this emerging multiphysics capability.

  11. Selling management on the cost benefits of EMS programs

    SciTech Connect

    Beck, W.B.

    1999-07-01

    One of the persistent misconceptions by management is that environmental programs are always a cost to the business. Management tolerates this situation because they recognize the legal and other ethical considerations related to environmental programs, however, they still regard them as a cost and a necessary evil. This paper will present several ideas that can be put into practice by the environmental professionals to counter this management perception. These include the identification and use of macro scale and micro scale cost considerations in the environmental balance sheet to provide management with a different and perhaps more realistic view of the worth of the program. This cost accounting approach should be viewed as just one of the several systems that should make up the modern day environmental management systems (EMS) program.

  12. Making connections. Voice and data solutions for EMS.

    PubMed

    Careless, James; Erich, John

    2008-08-01

    Communications used to be so simple-1) grab the radio, 2) push and talk. Now we're besieged by a confusing assortment of technology and terms-wideband, broadband, VoIP, RoIP, ect.- and a constand thrumming imperative to achieve and improve and perfect some mystical state of full interoperability. Frankly, it can all be a bit much. With this supplement, we hope to clarify you options. We examine the importance of broadband for EMS, with its potential for larger data "pipes" between the hospital and the field; advances in the promising technologies of Voice over IP and Radio over IP; and how some systems are improving their interconnectedness and resulting operations. The jargon can be overwhelming, but the ideas are worth understanding. PMID:18814746

  13. EM modeling of RF drive in DTL tank 4

    SciTech Connect

    Kurennoy, Sergey S.

    2012-06-19

    A 3-D MicroWave Studio model for the RF drive in the LANSCE DTL tank 4 has been built. Both eigensolver and time-domain modeling are used to evaluate maximal fields in the drive module and RF coupling. The LANSCE DTL tank 4 has recently been experiencing RF problems, which may or may not be related to its replaced RF coupler. This situation stimulated a request by Dan Rees to provide EM modeling of the RF drive in the DTL tank 4 (T4). Jim O'Hara provided a CAD model that was imported into the CST Microwave Studio (MWS) and after some modifications became a part of a simplified MWS model of the T4 RF drive. This technical note describes the model and presents simulation results.

  14. TrakEM2 Software for Neural Circuit Reconstruction

    PubMed Central

    Cardona, Albert; Saalfeld, Stephan; Schindelin, Johannes; Arganda-Carreras, Ignacio; Preibisch, Stephan; Longair, Mark; Tomancak, Pavel; Hartenstein, Volker; Douglas, Rodney J.

    2012-01-01

    A key challenge in neuroscience is the expeditious reconstruction of neuronal circuits. For model systems such as Drosophila and C. elegans, the limiting step is no longer the acquisition of imagery but the extraction of the circuit from images. For this purpose, we designed a software application, TrakEM2, that addresses the systematic reconstruction of neuronal circuits from large electron microscopical and optical image volumes. We address the challenges of image volume composition from individual, deformed images; of the reconstruction of neuronal arbors and annotation of synapses with fast manual and semi-automatic methods; and the management of large collections of both images and annotations. The output is a neural circuit of 3d arbors and synapses, encoded in NeuroML and other formats, ready for analysis. PMID:22723842

  15. TrakEM2 software for neural circuit reconstruction.

    PubMed

    Cardona, Albert; Saalfeld, Stephan; Schindelin, Johannes; Arganda-Carreras, Ignacio; Preibisch, Stephan; Longair, Mark; Tomancak, Pavel; Hartenstein, Volker; Douglas, Rodney J

    2012-01-01

    A key challenge in neuroscience is the expeditious reconstruction of neuronal circuits. For model systems such as Drosophila and C. elegans, the limiting step is no longer the acquisition of imagery but the extraction of the circuit from images. For this purpose, we designed a software application, TrakEM2, that addresses the systematic reconstruction of neuronal circuits from large electron microscopical and optical image volumes. We address the challenges of image volume composition from individual, deformed images; of the reconstruction of neuronal arbors and annotation of synapses with fast manual and semi-automatic methods; and the management of large collections of both images and annotations. The output is a neural circuit of 3d arbors and synapses, encoded in NeuroML and other formats, ready for analysis. PMID:22723842

  16. Kaisen. EMS as theater of the streets. Part two.

    PubMed

    Dernocoeur, K; Taigman, M

    1991-03-01

    Passing an EMT or paramedic course is a considerable achievement, as you have had to acquire a huge and fascinating volume of medical knowledge. But, did the program teach you acting skills? Acting? Whoever said that EMS professionals need to know anything about acting? We submit that you do; prehospital workers can gain many unanticipated benefits by using various acting skills and tactics in the field. One such benefit is the avoidance of the "complacency trap," or the boredom that can develop if you adopt the viewpoint that one crisis is much like another. But, more importantly, you will be more effective at delivering prehospital care, and you'll have a lot more fun on the job. PMID:10110186

  17. Suspended-Patch Antenna With Inverted, EM-Coupled Feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2004-01-01

    An improved suspended-patch antenna has been designed to operate at a frequency of about 23 GHz with linear polarization and to be one of four identical antennas in a rectangular array. The antenna includes a parasitic patch on top of a suspended dielectric superstrate, an active patch on top of a suspended dielectric substrate, a microstrip on the bottom of the dielectric substrate, and a ground plane. The microstrip, the ground plane, the airgap between them, and the dielectric substrate together constitute a transmission line that has an impedance of 50 Ohm and is electromagnetically (EM) coupled to the active patch. The parasitic patch is, in turn, excited by the active patch. The microstrip feed is characterized as inverted because the microstrip is on the bottom of the substrate, whereas microstrips are usually placed on the tops of dielectric substrates

  18. User's guide for the PWR LOCA analysis capability of the WRAP-EM system

    SciTech Connect

    Beranek, F; Gregory, M V

    1980-02-01

    The Water Reactor Analysis Package (WRAP) has been expanded to provide the capability to analyze loss-of-coolant accidents (LOCAs) in both pressurized water reactors (PWRs) and boiling water reactors (BWRs) by using evaluation models (EMs). The input specifications for modules in the WRAP-EM system are presented in this document along with the JOSHUA input templates. This document, along with the WRAP user's guide, provides a step-by-step procedure for setting up a PWR data base for the WRAP-EM system. 12 refs.

  19. Time-Lapse inversion of EM Tomography data for polymer-injected hydrocarbon reservoirs

    NASA Astrophysics Data System (ADS)

    Cheon, Seiwook; Park, Chanho; Nam, Myung Jin; Son, Jeong-Sul

    2015-04-01

    Polymer flooding is a method to increase the production of hydrocarbon reservoir by injecting polymer solution into the reservoir. For a study on the monitoring fluid variation within the reservoir, we first make analysis on seismic- and electromagnetic (EM)- tomography responses for seismic and electrical-resistivity rock physics models (RPMs) of the reservoir considering polymer fluid. Constructing RPMs are dependent on not only geologic characteristics of reservoir but also reservoir parameters such as fluid-type, fluid saturation, pressure and temperature. When making RPM for monitoring analysis, we assume the geology does not changes while reservoir parameters change to affect responses of seismic and EM tomography data. Specifically when constructing electrical-resistivity RPM, we consider three different types of hydrocarbon reservoirs, which are clean sand, shaly sand, sand-shale lamination, while considering two different types of waters (fresh water and salt water) to make 2wt% polymer solution. To compute time lapse EM and seismic tomography responses for corresponding RPMs of polymer-injected reservoirs, we used 2.5D finite element EM modeling algorithm and staggered-grid finite difference elastic modeling algorithm, respectively. Comparison between sensitivities of seismic and EM tomography to polymer injection confirms that EM tomography is more sensitivity to the polymer injection. For the evaluation of the potential of EM tomography to monitor polymer flooding, this study subsequently develops an efficient time-lapse EM tomography inversion algorithm based on the 2.5D EM tomography modeling. Using the inversion algorithm, we inverted the time-lapse EM tomography data to construct true resistivity models of polymer-injected reservoirs and analyze differences between them. From the time-lapse inversion results, we can observe the differences in time lapse responses between using fresh water and salt water have been decreased in the inverted time

  20. Integration of artificial intelligence applications in the EMS: Issues and solutions

    SciTech Connect

    Bann, J.; Irisarri, G.; Kirschen, D.; Miller, B.; Mokhtari, S.

    1996-02-01

    This paper discusses the issues which must be addressed when integrating Artificial Intelligence (AI) and, in particular, expert system applications in an Energy Management System (EMS) environment. It is argued that these issues can be resolved by creating an environment which supports all the interfaces between the Artificial Intelligence (AI) applications and the EMS. This environment should also be responsible for maintaining a model of the power system common to all the AI applications. Once this environment has been created, AI applications can be easily plugged into the EMS. The design of such an environment is described and case studies of its implementation are provided to illustrate its flexibility.

  1. Stochastic EM algorithm for nonlinear state estimation with model uncertainties

    NASA Astrophysics Data System (ADS)

    Zia, Amin; Kirubarajan, Thiagalingam; Reilly, James P.; Shirani, Shahram

    2004-01-01

    In most solutions to state estimation problems like, for example, target tracking, it is generally assumed that the state evolution and measurement models are known a priori. The model parameters include process and measurement matrices or functions as well as the corresponding noise statistics. However, there are situations where the model parameters are not known a priori or are known only partially (i.e., with some uncertainty). Moreover, there are situations where the measurement is biased. In these scenarios, standard estimation algorithms like the Kalman filter and the extended Kalman Filter (EKF), which assume perfect knowledge of the model parameters, are not accurate. In this paper, the problem with uncertain model parameters is considered as a special case of maximum likelihood estimation with incomplete-data, for which a standard solution called the expectation-maximization (EM) algorithm exists. In this paper a new extension to the EM algorithm is proposed to solve the more general problem of joint state estimation and model parameter identification for nonlinear systems with possibly non-Gaussian noise. In the expectation (E) step, it is shown that the best variational distribution over the state variables is the conditional posterior distribution of states given all the available measurements and inputs. Therefore, a particular type of particle filter is used to estimate and update the posterior distribution. In the maximization (M) step the nonlinear measurement process parameters are approximated using a nonlinear regression method for adjusting the parameters of a mixture of Gaussians (MofG). The proposed algorithm is used to solve a nonlinear bearing-only tracking problem similar to the one reported recently with uncertain measurement process. It is shown that the algorithm is capable of accurately tracking the state vector while identifying the unknown measurement dynamics. Simulation results show the advantages of the new technique over standard

  2. Stochastic EM algorithm for nonlinear state estimation with model uncertainties

    NASA Astrophysics Data System (ADS)

    Zia, Amin; Kirubarajan, Thiagalingam; Reilly, James P.; Shirani, Shahram

    2003-12-01

    In most solutions to state estimation problems like, for example, target tracking, it is generally assumed that the state evolution and measurement models are known a priori. The model parameters include process and measurement matrices or functions as well as the corresponding noise statistics. However, there are situations where the model parameters are not known a priori or are known only partially (i.e., with some uncertainty). Moreover, there are situations where the measurement is biased. In these scenarios, standard estimation algorithms like the Kalman filter and the extended Kalman Filter (EKF), which assume perfect knowledge of the model parameters, are not accurate. In this paper, the problem with uncertain model parameters is considered as a special case of maximum likelihood estimation with incomplete-data, for which a standard solution called the expectation-maximization (EM) algorithm exists. In this paper a new extension to the EM algorithm is proposed to solve the more general problem of joint state estimation and model parameter identification for nonlinear systems with possibly non-Gaussian noise. In the expectation (E) step, it is shown that the best variational distribution over the state variables is the conditional posterior distribution of states given all the available measurements and inputs. Therefore, a particular type of particle filter is used to estimate and update the posterior distribution. In the maximization (M) step the nonlinear measurement process parameters are approximated using a nonlinear regression method for adjusting the parameters of a mixture of Gaussians (MofG). The proposed algorithm is used to solve a nonlinear bearing-only tracking problem similar to the one reported recently with uncertain measurement process. It is shown that the algorithm is capable of accurately tracking the state vector while identifying the unknown measurement dynamics. Simulation results show the advantages of the new technique over standard

  3. DOE-EM-45 PACKAGING OPERATIONS AND MAINTENANCE COURSE

    SciTech Connect

    Watkins, R.; England, J.

    2010-05-28

    Savannah River National Laboratory - Savannah River Packaging Technology (SRNL-SRPT) delivered the inaugural offering of the Packaging Operations and Maintenance Course for DOE-EM-45's Packaging Certification Program (PCP) at the University of South Carolina Aiken on September 1 and 2, 2009. Twenty-nine students registered, attended, and completed this training. The DOE-EM-45 Packaging Certification Program (PCP) sponsored the presentation of a new training course, Packaging Maintenance and Operations, on September 1-2, 2009 at the University of South Carolina Aiken (USC-Aiken) campus in Aiken, SC. The premier offering of the course was developed and presented by the Savannah River National Laboratory, and attended by twenty-nine students across the DOE, NNSA and private industry. This training informed package users of the requirements associated with handling shipping containers at a facility (user) level and provided a basic overview of the requirements typically outlined in Safety Analysis Report for Packaging (SARP) Chapters 1, 7, and 8. The course taught packaging personnel about the regulatory nature of SARPs to help reduce associated and often costly packaging errors. Some of the topics covered were package contents, loading, unloading, storage, torque requirements, maintaining records, how to handle abnormal conditions, lessons learned, leakage testing (including demonstration), and replacement parts. The target audience for this course was facility operations personnel, facility maintenance personnel, and field quality assurance personnel who are directly involved in the handling of shipping containers. The training also aimed at writers of SARP Chapters 1, 7, and 8, package designers, and anyone else involved in radioactive material packaging and transportation safety. Student feedback and critiques of the training were very positive. SRNL will offer the course again at USC Aiken in September 2010.

  4. Astronomy, Art and Mythology in a Public Elementary School in Itaocara/rj. (Spanish Title: Astronomía, Arte y Mitologia en el Ensino Fundamental en Una Escuela de la Red Estatal en ITAOCARA/RJ.) Astronomia, Arte e Mitologia no Ensino Fundamental em Escola da Rede Estadual em ITAOCARA/RJ

    NASA Astrophysics Data System (ADS)

    Oliveira Bernardes, Adriana; Ramos dos Santos, Arleidimar

    2008-12-01

    conocimientos recibidos. El trabajo en sí ha mostrado además de la posibilidad de la inclusión de la Astronomía en la Educación Primaria, la posibilidad de un trabajo interdisciplinario en los niveles iniciales incluyendo Astronomía, Arte y Mitología. Los resultados presentados por los estudiantes en las Olimpiadas promovidas en la escuela y por la OBA (Olimpiada Brasilera de Astronomía) permitieron verificar un creciente aprendizaje y estimulo hacia las materias científicas, comprobados por la apropiada expresión de los conceptos adquiridos de astronomía y presentados en evaluaciones o en informes obtenidos de ellos mismos, sus familias y profesores. Desenvolvendo um trabalho voluntário junto aos alunos do ensino fundamental no 1º ciclo (1ª a 4ª série), os monitores de Astronomia membros do CAIMP (Clube de Astronomia de Itaocara Marcos Pontes), que eram em sua maioria alunos do ensino médio, desenvolveram um trabalho de aproximação entre os alunos do Colégio Estadual Teotônio Brandão Vilela e os temas envolvendo Ciências e Astronomia. Através de oficinas de informática, artes, vídeos educativos e teatros de fantoches, os alunos puderam expressar seus conhecimentos e emoções diante das lendas mitológicas com as quais começaram a ter contato. O trabalho desenvolvido pelos monitores junto aos alunos proporcionou a integração entre as turmas do colégio e os levou a participação em atividades de maneira a estimular sua oralidade e aumentar sua auto-estima. Trabalhando várias formas de expressões, os alunos puderam realizar seus experimentos e conhecer alguns conceitos de Física e Astronomia, enquanto adquiriam autonomia para se expressarem de acordo com seus sentimentos e conhecimentos adquiridos. O trabalho em si mostrou além da possibilidade de inserção de Astronomia no Ensino Fundamental, a possibilidade de realização de um trabalho interdisciplinar nas séries iniciais envolvendo Astronomia, Arte e Mitologia. Os resultados apresentados

  5. Vibrational symmetry classification and torsional tunneling splitting patterns in G6(EM), G12, and G36(EM) molecules

    NASA Astrophysics Data System (ADS)

    Lattanzi, F.; di Lauro, C.

    It is shown that the torsional splitting patterns in methanol-like molecules, with the excitation of small amplitude vibrational modes in the methyl group, are determined by mechanisms that can be formulated in an almost identical fashion to that for ethane-like molecules. This is achieved by treating ethane-like molecules by the internal axis method (IAM) and methanol-like molecules by the principal axis method (PAM) or rho-axis method (RAM). Using the extended molecular groups G6(EM) or C6v(M) for methanol and G36(EM) for ethane, vibrations perpendicular to the internal rotation axis are conveniently described by modes of higher degeneracy (E for methanol and Gs for ethane) in the absence of coupling of top and frame. Head-tail coupling operators, except the cos-type barrier terms, lower the degeneracy, causing vibrational splittings. Coupled vibrational pairs with torsional splitting patterns that we call 'regular' (pure A1, A2 pairs for methanol and pure E1d, E2d pairs for ethane) or 'inverted' (pure B1, B2 pairs for methanol and pure E1s, E2s pairs for ethane) can be formed as limit cases. Actual splitting patterns occur between the above limits, and are basically determined by torsional Coriolis coupling, which can tune more or less to resonance pairs of uncoupled basis levels linked by specific head-tail coupling operators. The inversion of torsional splitting patterns, observed in perpendicular vibrational modes of the methyl group of methanol, can be predicted by these theoretical considerations. Similar considerations apply to molecules of G12 symmetry.

  6. EMDataBank.org: unified data resource for CryoEM

    PubMed Central

    Lawson, Catherine L.; Baker, Matthew L.; Best, Christoph; Bi, Chunxiao; Dougherty, Matthew; Feng, Powei; van Ginkel, Glen; Devkota, Batsal; Lagerstedt, Ingvar; Ludtke, Steven J.; Newman, Richard H.; Oldfield, Tom J.; Rees, Ian; Sahni, Gaurav; Sala, Raul; Velankar, Sameer; Warren, Joe; Westbrook, John D.; Henrick, Kim; Kleywegt, Gerard J.; Berman, Helen M.; Chiu, Wah

    2011-01-01

    Cryo-electron microscopy reconstruction methods are uniquely able to reveal structures of many important macromolecules and macromolecular complexes. EMDataBank.org, a joint effort of the Protein Data Bank in Europe (PDBe), the Research Collaboratory for Structural Bioinformatics (RCSB) and the National Center for Macromolecular Imaging (NCMI), is a global ‘one-stop shop’ resource for deposition and retrieval of cryoEM maps, models and associated metadata. The resource unifies public access to the two major archives containing EM-based structural data: EM Data Bank (EMDB) and Protein Data Bank (PDB), and facilitates use of EM structural data of macromolecules and macromolecular complexes by the wider scientific community. PMID:20935055

  7. Analysis of the electrochemistry of hemes with Ems spanning 800 mV

    PubMed Central

    Zheng, Zhong; Gunner, M. R.

    2009-01-01

    The free energy of heme reduction in different proteins is found to vary over more than 18 kcal/mol. It is a challenge to determine how proteins manage to achieve this enormous range of Ems with a single type of redox cofactor. Proteins containing 141 unique hemes of a-, b-, and c-type, with bis-His, His-Met, and aquo-His ligation were calculated using Multi-Conformation Continuum Electrostatics (MCCE). The experimental Ems range over 800 mV from −350 mV in cytochrome c3 to 450 mV in cytochrome c peroxidase (vs. SHE). The quantitative analysis of the factors that modulate heme electrochemistry includes the interactions of the heme with its ligands, the solvent, the protein backbone, and sidechains. MCCE calculated Ems are in good agreement with measured values. Using no free parameters the slope of the line comparing calculated and experimental Ems is 0.73 (R2 = 0.90), showing the method accounts for 73% of the observed Em range. Adding a +160 mV correction to the His-Met c-type hemes yields a slope of 0.97 (R2 = 0.93). With the correction 65% of the hemes have an absolute error smaller than 60 mV and 92% are within 120 mV. The overview of heme proteins with known structures and Ems shows both the lowest and highest potential hemes are c-type, whereas the b-type hemes are found in the middle Em range. In solution, bis-His ligation lowers the Em by ≈205 mV relative to hemes with His-Met ligands. The bis-His, aquo-His, and His-Met ligated b-type hemes all cluster about Ems which are ≈200 mV more positive in protein than in water. In contrast, the low potential bis-His c-type hemes are shifted little from in solution, whereas the high potential His-Met c-type hemes are raised by ≈300 mV from solution. The analysis shows that no single type of interaction can be identified as the most important in setting heme electrochemistry in proteins. For example, the loss of solvation (reaction field) energy, which raises the Em, has been suggested to be a major factor in

  8. Volta phase plate cryo-EM of the small protein complex Prx3

    PubMed Central

    Khoshouei, Maryam; Radjainia, Mazdak; Phillips, Amy J.; Gerrard, Juliet A.; Mitra, Alok K.; Plitzko, Jürgen M.; Baumeister, Wolfgang; Danev, Radostin

    2016-01-01

    Cryo-EM of large, macromolecular assemblies has seen a significant increase in the numbers of high-resolution structures since the arrival of direct electron detectors. However, sub-nanometre resolution cryo-EM structures are rare compared with crystal structure depositions, particularly for relatively small particles (<400 kDa). Here we demonstrate the benefits of Volta phase plates for single-particle analysis by time-efficient cryo-EM structure determination of 257 kDa human peroxiredoxin-3 dodecamers at 4.4 Å resolution. The Volta phase plate improves the applicability of cryo-EM for small molecules and accelerates structure determination. PMID:26817416

  9. 7. PHOTOCOPY, ELEVATIONS FOR E.M. BARRACKS, N.C.O. AND OFFICERS QUARTERS. ...

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

    7. PHOTOCOPY, ELEVATIONS FOR E.M. BARRACKS, N.C.O. AND OFFICERS QUARTERS. - NIKE Missile Base SL-40, Barracks No. 1, North end of base, southest of Basketball Court & northwest of Barracks No. 2, Hecker, Monroe County, IL

  10. The NAS Perchlorate Review: Adverse Effects?

    SciTech Connect

    Johnston, Richard B.; Corley, Richard; Cowan, Linda; Utiger, Robert D.

    2005-11-01

    To the editor: Drs. Ginsberg and Rice argue that the reference dose for perchlorate of 0.0007 mg/kg per day recommended by the National Academies’ Committee to Assess the Health Implications of Perchlorate Ingestion is not adequately protective. As members of the committee, we disagree. Ginsberg and Rice base their conclusion on three points. The first involves the designation of the point of departure as a NOEL (no-observed-effect level) versus a LOAEL (lowest-observed-adverse- effect level). The committee chose as its point of departure a dose of perchlorate (0.007 mg/kg per day) that when given for 14 days to 7 normal subjects did not cause a significant decrease in the group mean thyroid iodide uptake (Greer et al. 2002). Accordingly, the committee considered it a NOEL. Ginsberg and Rice focus on the fact that only 7 subjects were given that dose, and they 1seem to say that attention should be paid only to the results in those subjects in whom there was a 1fall in thyroid iodide uptake, and that the results in those in whom there was no fall or an increase should be ignored. They consider the dose to be a LOAEL because of the fall in uptake in those few subjects. It is important to note that a statistically significant decrease of, for example, 5% or even 10%, would not be biologically important and, more important, would not be sustained. For example, in another study (Braverman et al. 2004), administration of 0.04 mg/kg per day to normal subjects for 6 months had no effect on thyroid iodide uptake when measured at 3 and 6 months, and no effect on serum thyroid hormone or thyrotropin concentrations measured monthly (inspection of Figure 5A in the paper by Greer et al. suggests that this dose would inhibit thyroid iodide uptake by about 25% if measured at 2 weeks). The second issue involves database uncertainty. In clinical studies, perchlorate has been administered prospectively to 68 normal subjects for 2 weeks to 6 months. In one study (Brabant et al. 1992), a dose of 9.2 mg/kg per day for 4 weeks had no effect on thyroid function. In occupational studies, doses as high as 0.5 mg/kg per day were not associated with adverse effects on thyroid function in workers. In epidemiologic studies, there were no abnormalities in growth or thyroid function in children exposed life-long to 100 to 120 mg of perchlorate per liter of drinking water, or in pregnant women and newborn infants similarly exposed. Given the choice of a non-adverse effect (inhibition of iodide uptake by the thyroid) as the point of departure and the multiple studies in which doses of perchlorate much larger than 0.007 mg/kg per day had no effect on any aspect of thyroid function, the committee did not apply a database uncertainty factor. Finally, Ginsberg and Rice argue that inhibition of thyroid iodide uptake is adverse. That conclusion assumes that any acute inhibition would be sustained, so that thyroid hormone production would fall. That is not the case. There is remarkable compensation for even substantial reductions in thyroid iodide uptake – and thyroid hormone production. As noted above, subjects given 0.04 mg/kg per day for 6 months and 9.2 mg/kg per day for 4 weeks-doses that certainly would inhibit thyroid iodide uptake for a few weeks-had no fall in serum thyroid hormone or rise in serum thyrotropin concentrations (the hallmark of even minor systemic thyroid deficiency). Short-term inhibition of thyroid iodide uptake is not an adverse effect; it has no adverse consequences, because there is rapid compensation mediated by several independent processes. One is upregulation of the thyroid sodium-iodide transport system, as a result of intrathyroidal iodide deficiency. The second, should there be even a very small fall in thyroid hormone production, is an increase in thyrotropin secretion, resulting in overall stimulation of the thyroid gland.

  11. NAS Report Reveals Dangers From SST

    ERIC Educational Resources Information Center

    Fowler, Jo Ann V.

    1973-01-01

    Reported are some harmful effects of supersonic travel on humans and other living organisms. Slight decreases in ozone concentration as a result of emissions from the SST aircrafts reduce absorption of ultraviolet radiation. Effects of this may include skin cancer, distort balance of activity in cells and have a deleterious effect on insects and…

  12. NAS President Lauds NSF Peer Review System

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1977

    1977-01-01

    A National Academy of Sciences study of the National Science Foundation's system for evaluating research grant applications reveals it to be fair and equitable and refutes charges of bias favoring older, established scientists. (MLH)

  13. Ecological risk assessment framework -- the NAS perspective

    SciTech Connect

    Barnthouse, L.W.

    1993-06-01

    A Workshop on Ecological Risk Assessment was held on February 26--March 1, 1991, at Airlie House, Warrenton, Virginia. In addition to presentation and discussion of the case study papers, the workshop included breakout sessions to discuss conceptual and technical aspects of ecological risk assessment. A general consensus emerged that an ecological version of the 1983 framework is desirable and feasible. The committee concluded that the 1983 human health framework could be expanded to accomodate both human health and ecological risk assessment. For general applicability to ecological assessments, the 1983 scheme requires augmentation to address some of the interfaces between science and management, primarily because of the need to focus on appropriate questions relevant to applicable environmental law and policy under different circumstances. Specifically, the scheme needs modification to address (1) the influence of legal and regulatory considerations on the initial stages of ecological risk assessment and (2) the importance of characterizing ecological risks in terms that are intelligible to risk managers. The committee`s opinion is that these augmentations are as important for human health risk assessment as they are for ecological risk assessment. This paper briefly describes the framework recommended by the Committee and compares it to EPA`s recently-published Framework for Ecological Risk Assessment.

  14. Input to NAS Plasma 2010 panel

    SciTech Connect

    Molvik, A W

    2006-01-30

    A number of areas of plasma physics have had outstanding success over the last decade. The author comments on progress in understanding and manipulating particle beams, a variety of non-neutral plasmas. Some of the key manipulations were made possible by immersing a particle beam in neutral plasma in order to greatly reduce space-charge forces on the beam.

  15. Response to Questions on Presentation to NAS

    SciTech Connect

    Meier, W R

    2011-03-17

    Response to questions on the presentation 'Overview to Chamber and Power Plant Designs for IFE' made at the 1/29-31 meeting of the National Academies Committee on the Prospects for Inertial Confinement Fusion Energy Systems.

  16. The development of cryo-EM into a mainstream structural biology technique

    PubMed Central

    Nogales, Eva

    2016-01-01

    Single-particle cryo-electron microscopy (cryo-EM) has emerged over the last two decades as a technique capable of studying challenging systems that otherwise defy structural characterization. Recent technical advances have resulted in a ‘quantum leap’ in applicability, throughput and achievable resolution that has gained this technique worldwide attention. Here I discuss some of the major historical landmarks in the development of the cryo-EM field, ultimately leading to its present success. PMID:27110629

  17. The front lines of domestic violence. Training model for rural EMS personnel.

    PubMed

    Hall, Marcia; Becker, Vanessa

    2002-09-01

    1. Domestic violence is a major public health problem requiring committed, coordinated community response. 2. Domestic violence is a significant cause of morbidity and mortality for women and children in the United States. 3. EMS personnel play a frontline role in the critical response and prevention of domestic violence. 4. EMS education and training are requisite for safe, effective responses to domestic violence in rural communities. PMID:12235968

  18. Space resolution obtained with a highly segmented SCIFI e.m. calorimeter

    NASA Astrophysics Data System (ADS)

    Bertino, M.; Bini, C.; De Pedis, D.; De Zorzi, G.; Diambrini Palazzi, G.; Di Cosimo, G.; Di Domenico, A.; Gauzzi, P.; Zanello, D.

    1992-05-01

    During the setting up of the LEP-5 experiment, we tested a longitudinal SCIFI e.m. calorimeter, having a module cross area 25 × 25 mm 2 and 12.5 × 12.5 mm 2 for large and small modules respectively. The results were obtained with 10 and 50 GeV electrons, and concern the impact point resolution and the transverse distribution of the e.m. shower energy inside the calorimeter.

  19. Effects of Loaded Squat Exercise with and without Application of Superimposed EMS on Physical Performance.

    PubMed

    Wirtz, Nicolas; Zinner, Christoph; Doermann, Ulrike; Kleinoeder, Heinz; Mester, Joachim

    2016-03-01

    The aim of the present study was to investigate the effects of a multiple set squat exercise training intervention with superimposed electromyostimulation (EMS) on strength and power, sprint and jump performance. Twenty athletes from different disciplines participated and were divided into two groups: strength training (S) or strength training with superimposed EMS (S+E). Both groups completed the same training program twice a week over a six week period consisting of four sets of the 10 repetition maximum of back squats. Additionally, the S+E group had EMS superimposed to the squat exercise with simultaneous stimulation of leg and trunk muscles. EMS intensity was adjusted to 70% of individual pain threshold to ensure dynamic movement. Strength and power of different muscle groups, sprint, and vertical jump performance were assessed one week before (pre), one week after (post) and three weeks (re) following the training period. Both groups showed improvements in leg press strength and power, countermovement and squat jump performance and pendulum sprint (p < 0.05), with no changes for linear sprint. Differences between groups were only evident at the leg curl machine with greater improvements for the S+E group (p < 0.05). Common squat exercise training and squat exercise with superimposed EMS improves maximum strength and power, as well as jumping abilities in athletes from different disciplines. The greater improvements in strength performance of leg curl muscles caused by superimposed EMS with improvements in strength of antagonistic hamstrings in the S+E group are suggesting the potential of EMS to unloaded (antagonistic) muscle groups. Key pointsSimilar strength adaptations occurred after a 6 week 10 RM back squat exercise program with superimposed EMS (S+E) and 10 RM back squat exercise (S) alone.Specific adaptations for S+E at the leg curl muscles were evident.S and S+E improved SJ, CMJ and pendulum sprint performance.No improvement occurred in linear sprint

  20. Effects of Loaded Squat Exercise with and without Application of Superimposed EMS on Physical Performance

    PubMed Central

    Wirtz, Nicolas; Zinner, Christoph; Doermann, Ulrike; Kleinoeder, Heinz; Mester, Joachim

    2016-01-01

    The aim of the present study was to investigate the effects of a multiple set squat exercise training intervention with superimposed electromyostimulation (EMS) on strength and power, sprint and jump performance. Twenty athletes from different disciplines participated and were divided into two groups: strength training (S) or strength training with superimposed EMS (S+E). Both groups completed the same training program twice a week over a six week period consisting of four sets of the 10 repetition maximum of back squats. Additionally, the S+E group had EMS superimposed to the squat exercise with simultaneous stimulation of leg and trunk muscles. EMS intensity was adjusted to 70% of individual pain threshold to ensure dynamic movement. Strength and power of different muscle groups, sprint, and vertical jump performance were assessed one week before (pre), one week after (post) and three weeks (re) following the training period. Both groups showed improvements in leg press strength and power, countermovement and squat jump performance and pendulum sprint (p < 0.05), with no changes for linear sprint. Differences between groups were only evident at the leg curl machine with greater improvements for the S+E group (p < 0.05). Common squat exercise training and squat exercise with superimposed EMS improves maximum strength and power, as well as jumping abilities in athletes from different disciplines. The greater improvements in strength performance of leg curl muscles caused by superimposed EMS with improvements in strength of antagonistic hamstrings in the S+E group are suggesting the potential of EMS to unloaded (antagonistic) muscle groups. Key points Similar strength adaptations occurred after a 6 week 10 RM back squat exercise program with superimposed EMS (S+E) and 10 RM back squat exercise (S) alone. Specific adaptations for S+E at the leg curl muscles were evident. S and S+E improved SJ, CMJ and pendulum sprint performance. No improvement occurred in linear

  1. ModEM: A modular system for inversion of elecgtromagnetic geophysical data

    NASA Astrophysics Data System (ADS)

    Egbert, G. D.; Kelbert, A.; Meqbel, N.; Weng, A.

    2010-12-01

    We have developed a modular system of computer codes for inversion of electromagnetic (EM) geophysical data (ModEM). ModEM allows for rapid adaptation of inversion algorithms developed for one purpose (e.g., three-dimensional magnetotellurics (MT)) to other EM problems (e.g., controlled source EM). The modular approach can also simplify maintenance of the inversion code, as well as development of new capabilities -- e.g., allowing for new data types such as the inter-site transfer functions in MT, or modifying model regularization. Basic data objects (model parameters, solution vectors, data vectors) are treated as abstract data types, with a standard set of methods developed for each class, including creation and destruction, and, as appropriate, linear algebra or other vector space methods. Operators required for gradient computations are developed as mappings between these basic object classes. Only these abstract data objects and mappings are manipulated by higher level Jacobian and inversion routines, with no reference to the problem specific details required for a specific EM method, or for the numerical implementation of the forward solver. Required problem-specific components are instantiated at the lowest levels of the system, with details hidden from generic top-level routines by an interface layer. Parallelization using MPI has been implemented at the top level, and is thus applicable to any problem embedded in ModEM. To illustrate the flexibility of the system, we consider applications to two- and three-dimensional MT inversion, as well as simple controlled source EM problems.

  2. The Soils and Groundwater – EM-20 S&T Roadmap Quality Assurance Project Plan

    SciTech Connect

    Fix, N. J.

    2008-02-11

    The Soils and Groundwater – EM-20 Science and Technology Roadmap Project is a U.S. Department of Energy, Office of Environmental Management-funded initiative designed to develop new methods, strategies and technology for characterizing, modeling, remediating, and monitoring soils and groundwater contaminated with metals, radionuclides, and chlorinated organics. This Quality Assurance Project Plan provides the quality assurance requirements and processes that will be followed by EM-20 Roadmap Project staff.

  3. Pre-flight risk assessment in emergency medical service (EMS) helicopters

    NASA Technical Reports Server (NTRS)

    Shively, Robert J.

    1990-01-01

    A preflight risk assessment system (SAFE) was developed at NASA-Ames Research Center for civil EMS operations to assist pilots in making a decision objectively to accept or decline a mission. The ability of the SAFE system to predict risk profiles was examined at an EMS operator. Results of this field study showed that the usefulness of SAFE was largely dependent on the type of mission flown.

  4. Single-particle cryo-EM data acquisition by using direct electron detection camera.

    PubMed

    Wu, Shenping; Armache, Jean-Paul; Cheng, Yifan

    2016-02-01

    Recent advances in single-particle electron cryo-microscopy (cryo-EM) were largely facilitated by the application of direct electron detection cameras. These cameras feature not only a significant improvement in detective quantum efficiency but also a high frame rate that enables images to be acquired as 'movies' made of stacks of many frames. In this review, we discuss how the applications of direct electron detection cameras in cryo-EM have changed the way the data are acquired. PMID:26546989

  5. Using Molecular Simulation to Model High-Resolution Cryo-EM Reconstructions.

    PubMed

    Kirmizialtin, Serdal; Loerke, Justus; Behrmann, Elmar; Spahn, Christian M T; Sanbonmatsu, Karissa Y

    2015-01-01

    An explosion of new data from high-resolution cryo-electron microscopy (cryo-EM) studies has produced a large number of data sets for many species of ribosomes in various functional states over the past few years. While many methods exist to produce structural models for lower resolution cryo-EM reconstructions, high-resolution reconstructions are often modeled using crystallographic techniques and extensive manual intervention. Here, we present an automated fitting technique for high-resolution cryo-EM data sets that produces all-atom models highly consistent with the EM density. Using a molecular dynamics approach, atomic positions are optimized with a potential that includes the cross-correlation coefficient between the structural model and the cryo-EM electron density, as well as a biasing potential preserving the stereochemistry and secondary structure of the biomolecule. Specifically, we use a hybrid structure-based/ab initio molecular dynamics potential to extend molecular dynamics fitting. In addition, we find that simulated annealing integration, as opposed to straightforward molecular dynamics integration, significantly improves performance. We obtain atomistic models of the human ribosome consistent with high-resolution cryo-EM reconstructions of the human ribosome. Automated methods such as these have the potential to produce atomistic models for a large number of ribosome complexes simultaneously that can be subsequently refined manually. PMID:26068751

  6. Fusion to a homo-oligomeric scaffold allows cryo-EM analysis of a small protein.

    PubMed

    Coscia, Francesca; Estrozi, Leandro F; Hans, Fabienne; Malet, Hélène; Noirclerc-Savoye, Marjolaine; Schoehn, Guy; Petosa, Carlo

    2016-01-01

    Recent technical advances have revolutionized the field of cryo-electron microscopy (cryo-EM). However, most monomeric proteins remain too small (<100 kDa) for cryo-EM analysis. To overcome this limitation, we explored a strategy whereby a monomeric target protein is genetically fused to a homo-oligomeric scaffold protein and the junction optimized to allow the target to adopt the scaffold symmetry, thereby generating a chimeric particle suitable for cryo-EM. To demonstrate the concept, we fused maltose-binding protein (MBP), a 40 kDa monomer, to glutamine synthetase, a dodecamer formed by two hexameric rings. Chimeric constructs with different junction lengths were screened by biophysical analysis and negative-stain EM. The optimal construct yielded a cryo-EM reconstruction that revealed the MBP structure at sub-nanometre resolution. These findings illustrate the feasibility of using homo-oligomeric scaffolds to enable cryo-EM analysis of monomeric proteins, paving the way for applying this strategy to challenging structures resistant to crystallographic and NMR analysis. PMID:27485862

  7. New Developments in the Technology Readiness Assessment Process in US DOE-EM - 13247

    SciTech Connect

    Krahn, Steven; Sutter, Herbert; Johnson, Hoyt

    2013-07-01

    A Technology Readiness Assessment (TRA) is a systematic, metric-based process and accompanying report that evaluates the maturity of the technologies used in systems; it is designed to measure technology maturity using the Technology Readiness Level (TRL) scale pioneered by the National Aeronautics and Space Administration (NASA) in the 1980's. More recently, DoD has adopted and provided systematic guidance for performing TRAs and determining TRLs. In 2007 the GAO recommended that the DOE adopt the NASA/DoD methodology for evaluating technology maturity. Earlier, in 2006-2007, DOE-EM had conducted pilot TRAs on a number of projects at Hanford and Savannah River. In March 2008, DOE-EM issued a process guide, which established TRAs as an integral part of DOE-EM's Project Management Critical Decision Process. Since the development of its detailed TRA guidance in 2008, DOE-EM has continued to accumulate experience in the conduct of TRAs and the process for evaluating technology maturity. DOE has developed guidance on TRAs applicable department-wide. DOE-EM's experience with the TRA process, the evaluations that led to recently developed proposed revisions to the DOE-EM TRA/TMP Guide; the content of the proposed changes that incorporate the above lessons learned and insights are described. (authors)

  8. Visualizing Proteins and Macromolecular Complexes by Negative Stain EM: from Grid Preparation to Image Acquisition

    PubMed Central

    Booth, David S.; Avila-Sakar, Agustin; Cheng, Yifan

    2011-01-01

    Single particle electron microscopy (EM), of both negative stained or frozen hydrated biological samples, has become a versatile tool in structural biology 1. In recent years, this method has achieved great success in studying structures of proteins and macromolecular complexes 2, 3. Compared with electron cryomicroscopy (cryoEM), in which frozen hydrated protein samples are embedded in a thin layer of vitreous ice 4, negative staining is a simpler sample preparation method in which protein samples are embedded in a thin layer of dried heavy metal salt to increase specimen contrast 5. The enhanced contrast of negative stain EM allows examination of relatively small biological samples. In addition to determining three-dimensional (3D) structure of purified proteins or protein complexes 6, this method can be used for much broader purposes. For example, negative stain EM can be easily used to visualize purified protein samples, obtaining information such as homogeneity/heterogeneity of the sample, formation of protein complexes or large assemblies, or simply to evaluate the quality of a protein preparation. In this video article, we present a complete protocol for using an EM to observe negatively stained protein sample, from preparing carbon coated grids for negative stain EM to acquiring images of negatively stained sample in an electron microscope operated at 120kV accelerating voltage. These protocols have been used in our laboratory routinely and can be easily followed by novice users. PMID:22215030

  9. An erythromycin derivative, EM-523, induces motilin-like gastrointestinal motility in dogs.

    PubMed

    Inatomi, N; Satoh, H; Maki, Y; Hashimoto, N; Itoh, Z; Omura, S

    1989-11-01

    The effect of an erythromycin derivative, EM-523, on gastrointestinal motility was investigated in conscious dogs and compared with that of motilin cisapride, trimebutine and metoclopramide. In the fasting state, EM-523 given i.v. or i.d. at 3 micrograms/kg or more induced contractions in the stomach that migrated along the small intestine. The pattern of the contractions was very similar to that induced by motilin. In the digestive state, EM-523 increased the amplitude of gastric contractions. Cisapride and metoclopramide increased gastrointestinal motility both in the fasting and digestive states; however, their contractile pattern was different from that of EM-523. Trimebutine did not induce gastric motility in the fasting state but rather decreased gastric motility in the digestive state. The contractions induced by EM-523 and motilin were inhibited by atropine but were not affected by naloxone, suggesting that the cholinergic pathway is important in the exertion of their action. These results indicate that EM-523 mimics motilin in stimulating gastrointestinal motility and that this agent may be useful treat gastrointestinal disorders such as gastric stasis, gastroesophageal reflux, and postoperative ileus, and so forth. PMID:2810120

  10. Reservoir characterization and process monitoring with EM methods. 1994 Annual report

    SciTech Connect

    Wilt, M.

    1995-05-01

    During the past five years at Lawrence Livermore National Laboratory (LLNL) the authors have applied the EM induction method to the problem of petroleum reservoir characterization and enhanced oil recovery (EOR) monitoring. The goal is to develop practical tools for determining the electrical resistivity distribution between boreholes at a useful scale for reservoir characterization. During FY94 the authors conducted their largest field test to date. They applied crosshole and surface-to-borehole EM techniques to reservoir characterization at the Los Hills No. 3 oil field making three sets of measurements during the initial phase of the steam drive.From these data they were able to determine the resistivity and configuration of the oil sands, between the observation wells, and provide an image of the subsurface resistivity changes due to the steam drive. They also conducted a waterflood experiment at the Richmond Field Station facility using the borehole-to-surface EM technique. For this test they injected a small quantity of saltwater, and applied the Em technique to monitor the progress of the injected plume. Data collection for this experiment is complete but the results are yet to be interpreted. Finally, a project to understand EM propagation through steel casing was initiated in 1994. The goals of the experiment are to determine the limits and applications for crosswell EM surveys through steel well casing.

  11. An Uncertainty Analysis for Predicting Soil Profile Salinity Using EM Induction Data

    NASA Astrophysics Data System (ADS)

    Huang, Jingyi; Monteiro Santos, Fernando; Triantafilis, John

    2016-04-01

    Proximal soil sensing techniques such as electromagnetic (EM) induction have been used to identify and map the areal variation of average soil properties. However, soil varies with depth owing to the action of various soil forming factors (e.g., parent material and topography). In this work we collected EM data using an EM38 and EM34 meter along a 22-km transect in the Trangie District, Australia.We jointly inverted these data using EM4Soil software and compare our 2-dimensional model of true electrical conductivity (sigma - mS/m) with depth against measured electrical conductivity of a saturated soil-paste extract (ECe - dS/m) at depth of 0-16 m. Through the use of a linear regression (LR) model and by varying forward modelling algorithms (cumulative function and full solution), inversion algorithms (S1 and S2), and damping factor (lambda) we determined a suitable electromagnetic conductivity image (EMCI) which was optimal when using the full solution, S2 and lambda = 0.6. To evaluate uncertainty of the inversion process and the LR model, we conducted an uncertainty analysis. The distribution of the model misfit shows the largest uncertainty caused by inversion (mostly due to EM34-40) occurs at deeper profiles while the largest uncertainty of the LR model occurs where the soil profile is most saline. These uncertainty maps also illustrate us how the model accuracy can be improved in the future.

  12. Operation Protective Edge - A Unique Challenge for a Civilian EMS Agency.

    PubMed

    Jaffe, Eli; Strugo, Refael; Wacht, Oren

    2015-10-01

    During July through August 2014, Operation Protective Edge, a military conflict between Israel and the Hamas regime in Gaza, dramatically affected both populations. Magen David Adom (MDA), the Israeli national Emergency Medical Service (EMS) and a member of the Red Cross, faced a unique challenge during the conflict: to continue providing crucial service to the entire civilian population of Israel, which was under constant missile threat. This challenge included not only providing immediate care for routine EMS calls under missile threat, but also preparing and delivering immediate care to civilians injured in attacks on major cities, as well as small communities, in Israel. This task is a challenge for a civilian EMS agency that normally operates in a non-military environment, yet, in an instant, must enhance its capability to respond to a considerable threat to its population. During Operation Protective Edge, MDA provided care for 842 wounded civilians and utilized a significant amount of its resources. Providing EMS services for a civilian population in a mixed civilian/military scenario is a challenging task on a national level for an EMS system, especially when the threat lasts for weeks. This report describes MDA's preparedness and operations during Operation Protective Edge, and the unique EMS challenges and dilemmas the agency faced. PMID:26323985

  13. High-speed computation of the EM algorithm for PET image reconstruction

    SciTech Connect

    Rajan, K.; Patnaik, L.M.; Ramakrishna, J. )

    1994-10-01

    The PET image reconstruction based on the EM algorithm has several attractive advantages over the conventional convolution backprojection algorithms. However, two major drawbacks have impeded the routine use of the EM algorithm, namely, the long computational time due to slow convergence and the large memory required for the storage of the image, projection data and the probability matrix. In this study, the authors attempts to solve these two problems by parallelizing the EM algorithm on a multiprocessor system. The authors have implemented an extended hypercube (EH) architecture for the high-speed computation of the EM algorithm using the commercially available fast floating point digital signal processor (DSP) chips as the processing elements (PEs). The authors discuss and compare the performance of the EM algorithm on a 386/387 machine, CD 4360 mainframe, and on the EH system. The results show that the computational speed performance of an EH using DSP chips as PEs executing the EM image reconstruction algorithm is about 130 times better than that of the CD 4360 mainframe. The EH topology is expandable with more number of PEs.

  14. Fusion to a homo-oligomeric scaffold allows cryo-EM analysis of a small protein

    PubMed Central

    Coscia, Francesca; Estrozi, Leandro F.; Hans, Fabienne; Malet, Hélène; Noirclerc-Savoye, Marjolaine; Schoehn, Guy; Petosa, Carlo

    2016-01-01

    Recent technical advances have revolutionized the field of cryo-electron microscopy (cryo-EM). However, most monomeric proteins remain too small (<100 kDa) for cryo-EM analysis. To overcome this limitation, we explored a strategy whereby a monomeric target protein is genetically fused to a homo-oligomeric scaffold protein and the junction optimized to allow the target to adopt the scaffold symmetry, thereby generating a chimeric particle suitable for cryo-EM. To demonstrate the concept, we fused maltose-binding protein (MBP), a 40 kDa monomer, to glutamine synthetase, a dodecamer formed by two hexameric rings. Chimeric constructs with different junction lengths were screened by biophysical analysis and negative-stain EM. The optimal construct yielded a cryo-EM reconstruction that revealed the MBP structure at sub-nanometre resolution. These findings illustrate the feasibility of using homo-oligomeric scaffolds to enable cryo-EM analysis of monomeric proteins, paving the way for applying this strategy to challenging structures resistant to crystallographic and NMR analysis. PMID:27485862

  15. Method for estimating dynamic EM tracking accuracy of surgical navigation tools

    NASA Astrophysics Data System (ADS)

    Nafis, Christopher; Jensen, Vern; Beauregard, Lee; Anderson, Peter

    2006-03-01

    Optical tracking systems have been used for several years in image guided medical procedures. Vendors often state static accuracies of a single retro-reflective sphere or LED. Expensive coordinate measurement machines (CMM) are used to validate the positional accuracy over the specified working volume. Users are interested in the dynamic accuracy of their tools. The configuration of individual sensors into a unique tool, the calibration of the tool tip, and the motion of the tool contribute additional errors. Electromagnetic (EM) tracking systems are considered an enabling technology for many image guided procedures because they are not limited by line-of-sight restrictions, take minimum space in the operating room, and the sensors can be very small. It is often difficult to quantify the accuracy of EM trackers because they can be affected by field distortion from certain metal objects. Many high-accuracy measurement devices can affect the EM measurements being validated. EM Tracker accuracy tends to vary over the working volume and orientation of the sensors. We present several simple methods for estimating the dynamic accuracy of EM tracked tools. We discuss the characteristics of the EM Tracker used in the GE Healthcare family of surgical navigation systems. Results for other tracking systems are included.

  16. EM techniques for archaeological laboratory experiments: preliminary results

    NASA Astrophysics Data System (ADS)

    Capozzoli, Luigi; De Martino, Gregory; Giampaolo, Valeria; Raffaele, Luongo; Perciante, Felice; Rizzo, Enzo

    2015-04-01

    The electromagnetic techniques (EM) are based on the investigation of subsoil geophysical parameters and in the archaeological framework they involve in studying contrasts between the buried cultural structures and the surrounding materials. Unfortunately, the geophysical contrast between archaeological features and surrounding soils sometimes are difficult to define due to problems of sensitivity and resolution both related on the characteristic of the subsoil and the geophysical methods. For this reason an experimental activity has been performed in the Hydrogeosite laboratory addressed on the assessment of the capability of geophysical techniques to detect archeological remains placed in the humid/saturated subsoil. At Hydrogeosite Laboratory of CNR-IMAA, a large scale sand-box is located, consisting on a pool shape structures of 230m3 where archaeological remains have been installed . The remains are relative to a living environment and burial of Roman times (walls, tombs, roads, harbour, etc.) covered by sediments. In order to simulate lacustrine and wetland condition and to simulate extreme events (for example underwater landslide, fast natural erosion coast, etc.) the phreatic level was varied and various acquisitions for the different scenarios were performed. In order to analyze the EM behavior of the buried small archaeological framework, ground penetrating radar (GPR) and electrical resistivity tomographies were performed. With GPR, analysis in time domain and frequency domain were performed and coupled to information obtained through resistivity analysis with the support of numerical simulations used to compare the real data with those modeled. A dense grid was adopted for 400 and 900 MHz e-m acquisitions in both the directions, the maximum depth of investigation was limited and less than 3 meters. The same approach was used for ERT acquisition where different array are employed, in particular 3D configuration was used to carry out a 3D resistivity

  17. Tide-driven fluid mud transport in the Ems estuary

    NASA Astrophysics Data System (ADS)

    Becker, Marius; Maushake, Christian; Winter, Christian

    2014-05-01

    The Ems estuary, located at the border between The Netherlands and Germany, experienced a significant change of the hydrodynamic regime during the past decades, as a result of extensive river engineering. With the net sediment transport now being flood-oriented, suspended sediment concentrations have increased dramatically, inducing siltation and formation of fluid mud layers, which, in turn, influence hydraulic flow properties, such as turbulence and the apparent bed roughness. Here, the process-based understanding of fluid mud is essential to model and predict mud accumulation, not only regarding the anthropogenic impact, but also in view of the expected changes of environmental boundary conditions, i.e., sea level rise. In the recent past, substantial progress has been made concerning the understanding of estuarine circulation and influence of tidal asymmetry on upstream sediment accumulation. While associated sediment transport formulations have been implemented in the framework of numerical modelling systems, in-situ data of fluid mud are scarce. This study presents results on tide-driven fluid mud dynamics, measured during four tidal cycles aside the navigation channel in the Ems estuary. Lutoclines, i.e., strong vertical density gradients, were detected by sediment echo sounder (SES). Acoustic Doppler current profiles (ADCP) of different acoustic frequencies were used to determine hydrodynamic parameters and the vertical distribution of suspended sediment concentrations in the upper part of the water column. These continuous profiling measurements were complemented by CTD, ADV, and OBS casts. SES and ADCP profiles show cycles of fluid mud entrainment during accelerating flow, and subsequent settling, and the reformation of a lutocline during decelerating flow and slack water. Significant differences are revealed between flood and ebb phase. Highest entrainment rates are measured at the beginning of the flood phase, associated with strong current shear and

  18. Exploration Depth of Multi-frequency Helicopter EM Systems

    NASA Astrophysics Data System (ADS)

    Yin, C.; Hodges, G.

    2004-05-01

    Due to the high resolution of hilicopter electromagnetic (HEM) systems, they are being widely used for shallow earth resistivity mapping problems. The traditional investigation of the exploration depth of a HEM system is based on the model of a single-frequency coil array over a layered earth. In this paper we extend the study to the multi-frequency HEM systems. We first determine for each frequency channel of a HEM system the maximal depth of a target, beyond which it cannot be identified from the EM signal. This is mathemically realized by assuming that the abnormal signal from the target is three times larger than the noise level of the HEM channel. Since each frequency channel of an HEM system has a different noise level and for different frequency channel the EM field has different penetration depth, we choose the biggest value of these depths as the depth of exploration. Different models are implemented in the study of this paper, including a layered earth model, a dipping plate or a dyke, a 3D ore body, etc. We use as example the Fugro DIGHEM system with three horizontal coplanar (HCP) coils (380 or 900, 7200, 56kHz) and two vertical coaxial (VCX) coils (900, 5500Hz). The following conclusions are obtained: 1. Except for a steeply dipping sheet, the HCP coil array has a larger depth of exploration than the VCX coil array; 2. The depth of exploration may be obtained from different frequency channels for different target geometries and different conductivity contrasts between the target and host rocks. This means that for a specific target geometry and conductivity contrast, we need to search such a frequency channel that offers the maximal value for depth of exploration; 3. Among the factors that influence the depth of exploration, the noise level of the HEM system is the key. The other factors include the geometry of the target and the conductivity contrast between the target and the host rocks, and the relative location between the HEM system and the target

  19. Abundâncias em estrelas de Bário

    NASA Astrophysics Data System (ADS)

    Allen, D. M.

    2003-08-01

    Estrelas de Bário apresentam linhas intensas de elementos produzidos pelo processos (ex: Ba, Y, Sr, Zr) e bandas intensas de CN, C2 e CH. A hipótese mais aceita sobre a origem deste grupo peculiar é a de que essas estrelas façam parte de sistemas binários, tendo recebido material enriquecido em elementos pesados da companheira mais evoluída. Apresentamos neste trabalho uma análise detalhada de uma amostra de estrelas desta classe, incluindo determinação de parâmetros atmosféricos e cálculo de abundâncias. As temperaturas efetivas foram determinadas a partir de dados fotométricos obtidos com o Fotrap instalado no telescópio Zeiss do LNA (Laboratório Nacional de Astrofísica) (B-V, V-I, R-I, V-R), e coletados na literatura nos catálogos Hipparcos (B-V), 2MASS (Two Micron All Sky Survey) (V-K) e The General Catalogue Photometric Data (sistema Geneva). Obtivemos uma faixa de temperaturas de 4400 £ Tef £ 6500. As metalicidades foram determinadas a partir de linhas de Fe I e Fe II, estando os resultados no intervalo -1 £ [Fe/H] £ +0.1. O log g foi determinado pelo equilíbrio de ionização e pela relação com a magnitude bolométrica, a temperatura e a massa, sendo os resultados na faixa 1.5 £ log g £ 4.5. As distâncias utilizadas foram determinadas com o auxílio das paralaxes Hipparcos, e as massas determinadas por modelos de isócronas. Os espectros utilizados foram obtidos com o espectrógrafo FEROS no Telescópio de 1,5m do ESO (European Southern Observatory). As abundâncias foram calculadas por meio de síntese espectral de linhas individuais incluindo elementos alfa, pico do Fe, s e r. Encontramos um excesso de elementos pesados em relação ao Fe, como esperado para estrelas de Bário.

  20. Monitoring Survivability and Infectivity of Porcine Epidemic Diarrhea Virus (PEDv) in the Infected On-Farm Earthen Manure Storages (EMS)

    PubMed Central

    Tun, Hein M.; Cai, Zhangbin; Khafipour, Ehsan

    2016-01-01

    In recent years, porcine epidemic diarrhea virus (PEDv) has caused major epidemics, which has been a burden to North America’s swine industry. Low infectious dose and high viability in the environment are major challenges in eradication of this virus. To further understand the viability of PEDv in the infected manure, we longitudinally monitored survivability and infectivity of PEDv in two open earthen manure storages (EMS; previously referred to as lagoon) from two different infected swine farms identified in the province of Manitoba, Canada. Our study revealed that PEDv could survive up to 9 months in the infected EMS after the initial outbreak in the farm. The viral load varied among different layers of the EMS with an average of 1.1 × 105 copies/ml of EMS, independent of EMS temperature and pH. In both studied EMS, the evidence of viral replication was observed through increased viral load in the later weeks of the samplings while there was no new influx of infected manure into the EMS, which was suggestive of presence of potential alternative hosts for PEDv within the EMS. Decreasing infectivity of virus over time irrespective of increased viral load suggested the possibility of PEDv evolution within the EMS and perhaps in the new host that negatively impacted virus infectivity. Viral load in the top layer of the EMS was low and mostly non-infective suggesting that environmental factors, such as UV and sunlight, could diminish the replicability and infectivity of the virus. Thus, frequent agitation of the EMS that could expose virus to UV and sunlight might be a potential strategy for reduction of PEDv load and infectivity in the infected EMS. PMID:27014197