Science.gov

Sample records for fast observation architecture

  1. Fast notification architecture for wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Hahk

    2013-03-01

    In an emergency, since it is vital to transmit the message to the users immediately after analysing the data to prevent disaster, this article presents the deployment of a fast notification architecture for a wireless sensor network. The sensor nodes of the proposed architecture can monitor an emergency situation periodically and transmit the sensing data, immediately to the sink node. We decide on the grade of fire situation according to the decision rule using the sensing values of temperature, CO, smoke density and temperature increasing rate. On the other hand, to estimate the grade of air pollution, the sensing data, such as dust, formaldehyde, NO2, CO2, is applied to the given knowledge model. Since the sink node in the architecture has a ZigBee interface, it can transmit the alert messages in real time according to analysed results received from the host server to the terminals equipped with a SIM card-type ZigBee module. Also, the host server notifies the situation to the registered users who have cellular phone through short message service server of the cellular network. Thus, the proposed architecture can adapt an emergency situation dynamically compared to the conventional architecture using video processing. In the testbed, after generating air pollution and fire data, the terminal receives the message in less than 3 s. In the test results, this system can also be applied to buildings and public areas where many people gather together, to prevent unexpected disasters in urban settings.

  2. Fast semivariogram computation using FPGA architectures

    NASA Astrophysics Data System (ADS)

    Lagadapati, Yamuna; Shirvaikar, Mukul; Dong, Xuanliang

    2015-02-01

    The semivariogram is a statistical measure of the spatial distribution of data and is based on Markov Random Fields (MRFs). Semivariogram analysis is a computationally intensive algorithm that has typically seen applications in the geosciences and remote sensing areas. Recently, applications in the area of medical imaging have been investigated, resulting in the need for efficient real time implementation of the algorithm. The semivariogram is a plot of semivariances for different lag distances between pixels. A semi-variance, γ(h), is defined as the half of the expected squared differences of pixel values between any two data locations with a lag distance of h. Due to the need to examine each pair of pixels in the image or sub-image being processed, the base algorithm complexity for an image window with n pixels is O(n2). Field Programmable Gate Arrays (FPGAs) are an attractive solution for such demanding applications due to their parallel processing capability. FPGAs also tend to operate at relatively modest clock rates measured in a few hundreds of megahertz, but they can perform tens of thousands of calculations per clock cycle while operating in the low range of power. This paper presents a technique for the fast computation of the semivariogram using two custom FPGA architectures. The design consists of several modules dedicated to the constituent computational tasks. A modular architecture approach is chosen to allow for replication of processing units. This allows for high throughput due to concurrent processing of pixel pairs. The current implementation is focused on isotropic semivariogram computations only. Anisotropic semivariogram implementation is anticipated to be an extension of the current architecture, ostensibly based on refinements to the current modules. The algorithm is benchmarked using VHDL on a Xilinx XUPV5-LX110T development Kit, which utilizes the Virtex5 FPGA. Medical image data from MRI scans are utilized for the experiments

  3. A Massively Parallel Adaptive Fast Multipole Method on Heterogeneous Architectures

    SciTech Connect

    Lashuk, Ilya; Chandramowlishwaran, Aparna; Langston, Harper; Nguyen, Tuan-Anh; Sampath, Rahul S; Shringarpure, Aashay; Vuduc, Richard; Ying, Lexing; Zorin, Denis; Biros, George

    2012-01-01

    We describe a parallel fast multipole method (FMM) for highly nonuniform distributions of particles. We employ both distributed memory parallelism (via MPI) and shared memory parallelism (via OpenMP and GPU acceleration) to rapidly evaluate two-body nonoscillatory potentials in three dimensions on heterogeneous high performance computing architectures. We have performed scalability tests with up to 30 billion particles on 196,608 cores on the AMD/CRAY-based Jaguar system at ORNL. On a GPU-enabled system (NSF's Keeneland at Georgia Tech/ORNL), we observed 30x speedup over a single core CPU and 7x speedup over a multicore CPU implementation. By combining GPUs with MPI, we achieve less than 10 ns/particle and six digits of accuracy for a run with 48 million nonuniformly distributed particles on 192 GPUs.

  4. A new architecture for fast ultrasound imaging

    SciTech Connect

    Cruza, J. F.; Camacho, J.; Moreno, J. M.; Medina, L.

    2014-02-18

    Some ultrasound imaging applications require high frame rate, for example 3D imaging and automated inspections of large components. Being the signal-processing throughput of the system the main bottleneck, parallel beamforming is required to achieve hundreds to thousands of images per second. Simultaneous A-scan line beamforming in all active channels is required to reach the intended high frame rate. To this purpose, a new parallel beamforming architecture that exploits the currently available processing resources available in state-of-the-art FPGAs is proposed. The work aims to get the optimal resource usage, high scalability and flexibility for different applications. To achieve these goals, the basic beamforming function is reformulated to be adapted to the DSP-cell architecture of state-of-the-art FPGAs. This allows performing simultaneous dynamic focusing on multiple A-scan lines. Some realistic examples are analyzed, evaluating resource requirements and maximum operating frequency. For example, a 128-channel system, with 128 scan lines and acquiring at 20 MSPS, can be built with 4 mid-range FPGAs, achieving up to 18000 frames per second, just limited by the maximum PRF. The gold standard Synthetic Transmit Aperture method (also called Total Focusing Method) can be carried out in real time at a processing rate of 140 high-resolution images per second (16 cm depth on steel)

  5. A new architecture for fast ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Cruza, J. F.; Camacho, J.; Moreno, J. M.; Medina, L.

    2014-02-01

    Some ultrasound imaging applications require high frame rate, for example 3D imaging and automated inspections of large components. Being the signal-processing throughput of the system the main bottleneck, parallel beamforming is required to achieve hundreds to thousands of images per second. Simultaneous A-scan line beamforming in all active channels is required to reach the intended high frame rate. To this purpose, a new parallel beamforming architecture that exploits the currently available processing resources available in state-of-the-art FPGAs is proposed. The work aims to get the optimal resource usage, high scalability and flexibility for different applications. To achieve these goals, the basic beamforming function is reformulated to be adapted to the DSP-cell architecture of state-of-the-art FPGAs. This allows performing simultaneous dynamic focusing on multiple A-scan lines. Some realistic examples are analyzed, evaluating resource requirements and maximum operating frequency. For example, a 128-channel system, with 128 scan lines and acquiring at 20 MSPS, can be built with 4 mid-range FPGAs, achieving up to 18000 frames per second, just limited by the maximum PRF. The gold standard Synthetic Transmit Aperture method (also called Total Focusing Method) can be carried out in real time at a processing rate of 140 high-resolution images per second (16 cm depth on steel).

  6. A fast, programmable hardware architecture for spaceborne SAR processing

    NASA Technical Reports Server (NTRS)

    Bennett, J. R.; Cumming, I. G.; Lim, J.; Wedding, R. M.

    1983-01-01

    The launch of spaceborne SARs during the 1980's is discussed. The satellite SARs require high quality and high throughput ground processors. Compression ratios in range and azimuth of greater than 500 and 150 respectively lead to frequency domain processing and data computation rates in excess of 2000 million real operations per second for C-band SARs under consideration. Various hardware architectures are examined and two promising candidates and proceeds to recommend a fast, programmable hardware architecture for spaceborne SAR processing are selected. Modularity and programmability are introduced as desirable attributes for the purpose of HTSP hardware selection.

  7. The NOAA Satellite Observing System Architecture Study

    NASA Technical Reports Server (NTRS)

    Volz, Stephen; Maier, Mark; Di Pietro, David

    2016-01-01

    NOAA is beginning a study, the NOAA Satellite Observing System Architecture (NSOSA) study, to plan for the future operational environmental satellite system that will follow GOES and JPSS, beginning about 2030. This is an opportunity to design a modern architecture with no pre-conceived notions regarding instruments, platforms, orbits, etc. The NSOSA study will develop and evaluate architecture alternatives to include partner and commercial alternatives that are likely to become available. The objectives will include both functional needs and strategic characteristics (e.g., flexibility, responsiveness, sustainability). Part of this study is the Space Platform Requirements Working Group (SPRWG), which is being commissioned by NESDIS. The SPRWG is charged to assess new or existing user needs and to provide relative priorities for observational needs in the context of the future architecture. SPRWG results will serve as input to the process for new foundational (Level 0 and Level 1) requirements for the next generation of NOAA satellites that follow the GOES-R, JPSS, DSCOVR, Jason-3, and COSMIC-2 missions.

  8. Fast adaptive composite grid methods on distributed parallel architectures

    NASA Technical Reports Server (NTRS)

    Lemke, Max; Quinlan, Daniel

    1992-01-01

    The fast adaptive composite (FAC) grid method is compared with the adaptive composite method (AFAC) under variety of conditions including vectorization and parallelization. Results are given for distributed memory multiprocessor architectures (SUPRENUM, Intel iPSC/2 and iPSC/860). It is shown that the good performance of AFAC and its superiority over FAC in a parallel environment is a property of the algorithm and not dependent on peculiarities of any machine.

  9. Fast-earth: A global image caching architecture for fast access to remote-sensing data

    NASA Astrophysics Data System (ADS)

    Talbot, B. G.; Talbot, L. M.

    We introduce Fast-Earth, a novel server architecture that enables rapid access to remote sensing data. Fast-Earth subdivides a WGS-84 model of the earth into small 400 × 400 meter regions with fixed locations, called plats. The resulting 3,187,932,913 indexed plats are accessed with a rapid look-up algorithm. Whereas many traditional databases store large original images as a series by collection time, requiring long searches and slow access times for user queries, the Fast-Earth architecture enables rapid access. We have prototyped a system in conjunction with a Fast-Responder mobile app to demonstrate and evaluate the concepts. We found that new data could be indexed rapidly in about 10 minutes/terabyte, high-resolution images could be chipped in less than a second, and 250 kB image chips could be delivered over a 3G network in about 3 seconds. The prototype server implemented on a very small computer could handle 100 users, but the concept is scalable. Fast-Earth enables dramatic advances in rapid dissemination of remote sensing data for mobile platforms as well as desktop enterprises.

  10. Fast, parallel implementation of particle filtering on the GPU architecture

    NASA Astrophysics Data System (ADS)

    Gelencsér-Horváth, Anna; Tornai, Gábor János; Horváth, András; Cserey, György

    2013-12-01

    In this paper, we introduce a modified cellular particle filter (CPF) which we mapped on a graphics processing unit (GPU) architecture. We developed this filter adaptation using a state-of-the art CPF technique. Mapping this filter realization on a highly parallel architecture entailed a shift in the logical representation of the particles. In this process, the original two-dimensional organization is reordered as a one-dimensional ring topology. We proposed a proof-of-concept measurement on two models with an NVIDIA Fermi architecture GPU. This design achieved a 411- μs kernel time per state and a 77-ms global running time for all states for 16,384 particles with a 256 neighbourhood size on a sequence of 24 states for a bearing-only tracking model. For a commonly used benchmark model at the same configuration, we achieved a 266- μs kernel time per state and a 124-ms global running time for all 100 states. Kernel time includes random number generation on the GPU with curand. These results attest to the effective and fast use of the particle filter in high-dimensional, real-time applications.

  11. New architecture of fast parallel multiplier using fast parallel counter with FPA (first partial product addition)

    NASA Astrophysics Data System (ADS)

    Lee, Mike M.; Cho, Byung Lok

    2001-11-01

    In this paper, we proposed a new First Partial product Addition (FPA) architecture with new compressor (or parallel counter) to CSA tree built in the process of adding partial product for improving speed in the fast parallel multiplier to improve the speed of calculating partial product by about 20% compared with existing parallel counter using full Adder. The new circuit reduces the CLA bit finding final sum by N/2 using the novel FPA architecture. A 5.14ns of multiplication speed of the 16X16 multiplier is obtained using 0.25um CMOS technology. The architecture of the multiplier is easily opted for pipeline design and demonstrates high speed performance.

  12. On-board B-ISDN fast packet switching architectures. Phase 2: Development. Proof-of-concept architecture definition report

    NASA Technical Reports Server (NTRS)

    Shyy, Dong-Jye; Redman, Wayne

    1993-01-01

    For the next-generation packet switched communications satellite system with onboard processing and spot-beam operation, a reliable onboard fast packet switch is essential to route packets from different uplink beams to different downlink beams. The rapid emergence of point-to-point services such as video distribution, and the large demand for video conference, distributed data processing, and network management makes the multicast function essential to a fast packet switch (FPS). The satellite's inherent broadcast features gives the satellite network an advantage over the terrestrial network in providing multicast services. This report evaluates alternate multicast FPS architectures for onboard baseband switching applications and selects a candidate for subsequent breadboard development. Architecture evaluation and selection will be based on the study performed in phase 1, 'Onboard B-ISDN Fast Packet Switching Architectures', and other switch architectures which have become commercially available as large scale integration (LSI) devices.

  13. Observing pulsars and fast transients with LOFAR

    NASA Astrophysics Data System (ADS)

    Stappers, B. W.; Hessels, J. W. T.; Alexov, A.; Anderson, K.; Coenen, T.; Hassall, T.; Karastergiou, A.; Kondratiev, V. I.; Kramer, M.; van Leeuwen, J.; Mol, J. D.; Noutsos, A.; Romein, J. W.; Weltevrede, P.; Fender, R.; Wijers, R. A. M. J.; Bähren, L.; Bell, M. E.; Broderick, J.; Daw, E. J.; Dhillon, V. S.; Eislöffel, J.; Falcke, H.; Griessmeier, J.; Law, C.; Markoff, S.; Miller-Jones, J. C. A.; Scheers, B.; Spreeuw, H.; Swinbank, J.; Ter Veen, S.; Wise, M. W.; Wucknitz, O.; Zarka, P.; Anderson, J.; Asgekar, A.; Avruch, I. M.; Beck, R.; Bennema, P.; Bentum, M. J.; Best, P.; Bregman, J.; Brentjens, M.; van de Brink, R. H.; Broekema, P. C.; Brouw, W. N.; Brüggen, M.; de Bruyn, A. G.; Butcher, H. R.; Ciardi, B.; Conway, J.; Dettmar, R.-J.; van Duin, A.; van Enst, J.; Garrett, M.; Gerbers, M.; Grit, T.; Gunst, A.; van Haarlem, M. P.; Hamaker, J. P.; Heald, G.; Hoeft, M.; Holties, H.; Horneffer, A.; Koopmans, L. V. E.; Kuper, G.; Loose, M.; Maat, P.; McKay-Bukowski, D.; McKean, J. P.; Miley, G.; Morganti, R.; Nijboer, R.; Noordam, J. E.; Norden, M.; Olofsson, H.; Pandey-Pommier, M.; Polatidis, A.; Reich, W.; Röttgering, H.; Schoenmakers, A.; Sluman, J.; Smirnov, O.; Steinmetz, M.; Sterks, C. G. M.; Tagger, M.; Tang, Y.; Vermeulen, R.; Vermaas, N.; Vogt, C.; de Vos, M.; Wijnholds, S. J.; Yatawatta, S.; Zensus, A.

    2011-06-01

    Low frequency radio waves, while challenging to observe, are a rich source of information about pulsars. The LOw Frequency ARray (LOFAR) is a new radio interferometer operating in the lowest 4 octaves of the ionospheric "radio window": 10-240 MHz, that will greatly facilitate observing pulsars at low radio frequencies. Through the huge collecting area, long baselines, and flexible digital hardware, it is expected that LOFAR will revolutionize radio astronomy at the lowest frequencies visible from Earth. LOFAR is a next-generation radio telescope and a pathfinder to the Square Kilometre Array (SKA), in that it incorporates advanced multi-beaming techniques between thousands of individual elements. We discuss the motivation for low-frequency pulsar observations in general and the potential of LOFAR in addressing these science goals. We present LOFAR as it is designed to perform high-time-resolution observations of pulsars and other fast transients, and outline the various relevant observing modes and data reduction pipelines that are already or will soon be implemented to facilitate these observations. A number of results obtained from commissioning observations are presented to demonstrate the exciting potential of the telescope. This paper outlines the case for low frequency pulsar observations and is also intended to serve as a reference for upcoming pulsar/fast transient science papers with LOFAR.

  14. Fast underdetermined BSS architecture design methodology for real time applications.

    PubMed

    Mopuri, Suresh; Reddy, P Sreenivasa; Acharyya, Amit; Naik, Ganesh R

    2015-01-01

    In this paper, we propose a high speed architecture design methodology for the Under-determined Blind Source Separation (UBSS) algorithm using our recently proposed high speed Discrete Hilbert Transform (DHT) targeting real time applications. In UBSS algorithm, unlike the typical BSS, the number of sensors are less than the number of the sources, which is of more interest in the real time applications. The DHT architecture has been implemented based on sub matrix multiplication method to compute M point DHT, which uses N point architecture recursively and where M is an integer multiples of N. The DHT architecture and state of the art architecture are coded in VHDL for 16 bit word length and ASIC implementation is carried out using UMC 90 - nm technology @V DD = 1V and @ 1MHZ clock frequency. The proposed architecture implementation and experimental comparison results show that the DHT design is two times faster than state of the art architecture. PMID:26737514

  15. Hardware architecture design of a fast global motion estimation method

    NASA Astrophysics Data System (ADS)

    Liang, Chaobing; Sang, Hongshi; Shen, Xubang

    2015-12-01

    VLSI implementation of gradient-based global motion estimation (GME) faces two main challenges: irregular data access and high off-chip memory bandwidth requirement. We previously proposed a fast GME method that reduces computational complexity by choosing certain number of small patches containing corners and using them in a gradient-based framework. A hardware architecture is designed to implement this method and further reduce off-chip memory bandwidth requirement. On-chip memories are used to store coordinates of the corners and template patches, while the Gaussian pyramids of both the template and reference frame are stored in off-chip SDRAMs. By performing geometric transform only on the coordinates of the center pixel of a 3-by-3 patch in the template image, a 5-by-5 area containing the warped 3-by-3 patch in the reference image is extracted from the SDRAMs by burst read. Patched-based and burst mode data access helps to keep the off-chip memory bandwidth requirement at the minimum. Although patch size varies at different pyramid level, all patches are processed in term of 3x3 patches, so the utilization of the patch-processing circuit reaches 100%. FPGA implementation results show that the design utilizes 24,080 bits on-chip memory and for a sequence with resolution of 352x288 and frequency of 60Hz, the off-chip bandwidth requirement is only 3.96Mbyte/s, compared with 243.84Mbyte/s of the original gradient-based GME method. This design can be used in applications like video codec, video stabilization, and super-resolution, where real-time GME is a necessity and minimum memory bandwidth requirement is appreciated.

  16. Contrasting genetic architectures of schizophrenia and other complex diseases using fast variance-components analysis.

    PubMed

    Loh, Po-Ru; Bhatia, Gaurav; Gusev, Alexander; Finucane, Hilary K; Bulik-Sullivan, Brendan K; Pollack, Samuela J; de Candia, Teresa R; Lee, Sang Hong; Wray, Naomi R; Kendler, Kenneth S; O'Donovan, Michael C; Neale, Benjamin M; Patterson, Nick; Price, Alkes L

    2015-12-01

    Heritability analyses of genome-wide association study (GWAS) cohorts have yielded important insights into complex disease architecture, and increasing sample sizes hold the promise of further discoveries. Here we analyze the genetic architectures of schizophrenia in 49,806 samples from the PGC and nine complex diseases in 54,734 samples from the GERA cohort. For schizophrenia, we infer an overwhelmingly polygenic disease architecture in which ≥71% of 1-Mb genomic regions harbor ≥1 variant influencing schizophrenia risk. We also observe significant enrichment of heritability in GC-rich regions and in higher-frequency SNPs for both schizophrenia and GERA diseases. In bivariate analyses, we observe significant genetic correlations (ranging from 0.18 to 0.85) for several pairs of GERA diseases; genetic correlations were on average 1.3 tunes stronger than the correlations of overall disease liabilities. To accomplish these analyses, we developed a fast algorithm for multicomponent, multi-trait variance-components analysis that overcomes prior computational barriers that made such analyses intractable at this scale. PMID:26523775

  17. Contrasting genetic architectures of schizophrenia and other complex diseases using fast variance components analysis

    PubMed Central

    Bhatia, Gaurav; Gusev, Alexander; Finucane, Hilary K; Bulik-Sullivan, Brendan K; Pollack, Samuela J; de Candia, Teresa R; Lee, Sang Hong; Wray, Naomi R; Kendler, Kenneth S; O’Donovan, Michael C; Neale, Benjamin M; Patterson, Nick

    2015-01-01

    Heritability analyses of GWAS cohorts have yielded important insights into complex disease architecture, and increasing sample sizes hold the promise of further discoveries. Here, we analyze the genetic architecture of schizophrenia in 49,806 samples from the PGC, and nine complex diseases in 54,734 samples from the GERA cohort. For schizophrenia, we infer an overwhelmingly polygenic disease architecture in which ≥71% of 1Mb genomic regions harbor ≥1 variant influencing schizophrenia risk. We also observe significant enrichment of heritability in GC-rich regions and in higher-frequency SNPs for both schizophrenia and GERA diseases. In bivariate analyses, we observe significant genetic correlations (ranging from 0.18 to 0.85) among several pairs of GERA diseases; genetic correlations were on average 1.3x stronger than correlations of overall disease liabilities. To accomplish these analyses, we developed a fast algorithm for multi-component, multi-trait variance components analysis that overcomes prior computational barriers that made such analyses intractable at this scale. PMID:26523775

  18. Quadrant architecture for fast in-place algorithms

    SciTech Connect

    Besslich, P.W.; Kurowski, J.O.

    1983-10-01

    The architecture proposed is tailored to support Radix-2/sup k/ based in-place processing of pictorial data. The algorithms make use of signal-flow graphs to describe 2-dimensional in-place operations suitable for image processing. They may be executed on a general-purpose computer but may also be supported by a special parallel architecture. Major advantages of the scheme are in-place processing and parallel access to disjoint sections of memory only. A quadtree-like decomposition of the picture prevents blocking and queuing of private and common buses. 9 references.

  19. Pulsar Observations with Radio Telescope FAST

    NASA Astrophysics Data System (ADS)

    Nan, Ren-Dong; Wang, Qi-Ming; Zhu, Li-Chun; Zhu, Wen-Bai; Jin, Cheng-Jin; Gan, Heng-Qian

    2006-12-01

    FAST, Five hundred meter Aperture Spherical Telescope, is the Chinese effort for the international project SKA, Square Kilometer Array. An innovative engineering concept and design pave a new road to realizing huge single dish in the most effective way. Three outstanding features of the telescope are the unique karst depressions as the sites, the active main reflector which corrects spherical aberration on the ground to achieve full polarization and wide band without involving complex feed system, and the light focus cabin driven by cables and servomechanism plus a parallel robot as secondary adjustable system to carry the most precise parts of the receivers. Besides a general coverage of those critical technologies involved in FAST concept, the progresses in demonstrating model being constructed at the Miyun Radio Observatory of the NAOC is introduced. Being the most sensitive radio telescope, FAST will enable astronomers to jumpstart many of science goals, for example, the natural hydrogen line surveying in distant galaxies, looking for the first generation of shining objects, hearing the possible signal from other civilizations, etc. Among these subjects, the most striking one could be pulsar study. Large scale survey by FAST will not only improve the statistics of the pulsar population, but also may offer us a good fortune to pick up more of the most exotic, even unknown types like a sub-millisecond pulsar or a neutron star -- black hole binary as the telescope is put into operation.

  20. On-board B-ISDN fast packet switching architectures. Phase 1: Study

    NASA Technical Reports Server (NTRS)

    Faris, Faris; Inukai, Thomas; Lee, Fred; Paul, Dilip; Shyy, Dong-Jye

    1993-01-01

    The broadband integrate services digital network (B-ISDN) is an emerging telecommunications technology that will meet most of the telecommunications networking needs in the mid-1990's to early next century. The satellite-based system is well positioned for providing B-ISDN service with its inherent capabilities of point-to-multipoint and broadcast transmission, virtually unlimited connectivity between any two points within a beam coverage, short deployment time of communications facility, flexible and dynamic reallocation of space segment capacity, and distance insensitive cost. On-board processing satellites, particularly in a multiple spot beam environment, will provide enhanced connectivity, better performance, optimized access and transmission link design, and lower user service cost. The following are described: the user and network aspects of broadband services; the current development status in broadband services; various satellite network architectures including system design issues; and various fast packet switch architectures and their detail designs.

  1. An End-to-End Architecture for Science Goal Driven Observing

    NASA Technical Reports Server (NTRS)

    Jones, Jeremy; Grosvenor, Sandy; Koratkar, Anuradha; Memarsadeghi, Nargess; Wolf, Karl; Obenschain, Arthur F. (Technical Monitor)

    2002-01-01

    New observatories will have greater on-board storage capacity and on-board processing capabilities. The new bottleneck will be download capacity. The cost of downlink time and limitations of bandwidth will end the era where all exposure data is downloaded and all data processing is performed on the ground. In addition, observing campaigns involving inherently variable targets will need scheduling flexibility to focus observing time and data download on exposures that are scientifically interesting. The ability to quickly recognize and react to such events by re-prioritizing the observing schedule will be an essential characteristic for maximizing scientific returns. It will also be a step towards increasing spacecraft autonomy, a major goal of NASA's strategic plan. The science goal monitoring (SGM) system is a proof-of-concept effort to address these challenges. We are developing an interactive distributed system that will use on-board processing and storage combined with event-driven interfaces with ground-based processing and operations, to enable fast re-prioritization of observing schedules, and to minimize time spent on non-optimized observations. SGM is initially aimed towards time-tagged observing modes used frequently in spectroscopic studies of varying targets. In particular, the SGM is collaborating with the proposed MIDEX-class mission Kronos team. The variable targets that Kronos seeks to study make an adaptive system such as SGM particularly valuable for achieving mission goals. However, the architecture and interfaces will also be designed for easy adaptability to other observing platforms, including ground-based systems and to work with different scheduling and pipeline processing systems. This talk will focus on our strategy for developing SGM and the technical challenges that we have encountered. We will discuss the SGM architecture as it applies to the Kronos mission and explain how it is scalable to other missions.

  2. Observations of fast VHF-bright positive breakdown

    NASA Astrophysics Data System (ADS)

    Stock, M.; Krehbiel, P. R.; Rison, W.; Lapierre, J. L.; Edens, H. E.

    2014-12-01

    Positive breakdown during lightning discharges is generally considered to be weak and slowly propagating, as high speed video observations show it to be optically weak, and studies of the development of cloud-to-ground (CG) and intracloud (IC) flashes show development in the negative charge region to be slow. With the proper instrumentation, however, fast positive breakdown is a relatively common feature of both CG and IC flashes. The breakdown is bright at VHF, but is smoothly continuous so that time-of-arrival VHF mapping systems such as the Lightning Mapping Array are usually unable to detect or locate its occurrence. However, the breakdown is easily locatable using interferometric mapping techniques. Such an interferometer was developed at NM Tech in the 1980s and used in the CaPE studies at Kennedy Space Center in 1991, where it observed fast (1-6 × 107 m/s), VHF-bright positive leaders propagating away from the source region of negative CG return strokes (Shao et al., 1995). Here we report new observations of fast positive breakdown, obtained with Langmuir Laboratory's flash-continuous broadband VHF interferometer, that confirm and substantially expand our understanding of the phenomena. Numerous examples have been observed following return strokes of negative CG flashes, including bolt-from-blue discharges, and during K-processes of both IC and CG flashes. The breakdown typically propagates a few kilometers at speeds on the order of 107 m/s and frequently produces some of the brightest radiation of the flash. A particularly interesting feature of the breakdown is that it propagates into regions of previously un-ionized air. Then following the breakdown, frequently no further VHF emission is seen along or beyond its channel, indicating that the channel formed is not conducting. But on occasion, especially during cloud-to-ground flashes, the end of the fast positive breakdown turns into a normal, slowly propagating positive leader.

  3. A Services-Oriented Architecture for Water Observations Data

    NASA Astrophysics Data System (ADS)

    Maidment, D. R.; Zaslavsky, I.; Valentine, D.; Tarboton, D. G.; Whitenack, T.; Whiteaker, T.; Hooper, R.; Kirschtel, D.

    2009-04-01

    Water observations data are time series of measurements made at point locations of water level, flow, and quality and corresponding data for climatic observations at point locations such as gaged precipitation and weather variables. A services-oriented architecture has been built for such information for the United States that has three components: hydrologic information servers, hydrologic information clients, and a centralized metadata cataloging system. These are connected using web services for observations data and metadata defined by an XML-based language called WaterML. A Hydrologic Information Server can be built by storing observations data in a relational database schema in the CUAHSI Observations Data Model, in which case, web services access to the data and metadata is automatically provided by query functions for WaterML that are wrapped around the relational database within a web server. A Hydrologic Information Server can also be constructed by custom-programming an interface to an existing water agency web site so that responds to the same queries by producing data in WaterML as do the CUAHSI Observations Data Model based servers. A Hydrologic Information Client is one which can interpret and ingest WaterML metadata and data. We have two client applications for Excel and ArcGIS and have shown how WaterML web services can be ingested into programming environments such as Matlab and Visual Basic. HIS Central, maintained at the San Diego Supercomputer Center is a repository of observational metadata for WaterML web services which presently indexes 342 million data measured at 1.75 million locations. This is the largest catalog water observational data for the United States presently in existence. As more observation networks join what we term "CUAHSI Water Data Federation", and the system accommodates a growing number of sites, measured parameters, applications, and users, rapid and reliable access to large heterogeneous hydrologic data repositories

  4. Fast readout architectures for large arrays of digital pixels: examples and applications.

    PubMed

    Gabrielli, A

    2014-01-01

    Modern pixel detectors, particularly those designed and constructed for applications and experiments for high-energy physics, are commonly built implementing general readout architectures, not specifically optimized in terms of speed. High-energy physics experiments use bidimensional matrices of sensitive elements located on a silicon die. Sensors are read out via other integrated circuits bump bonded over the sensor dies. The speed of the readout electronics can significantly increase the overall performance of the system, and so here novel forms of readout architectures are studied and described. These circuits have been investigated in terms of speed and are particularly suited for large monolithic, low-pitch pixel detectors. The idea is to have a small simple structure that may be expanded to fit large matrices without affecting the layout complexity of the chip, while maintaining a reasonably high readout speed. The solutions might be applied to devices for applications not only in physics but also to general-purpose pixel detectors whenever online fast data sparsification is required. The paper presents also simulations on the efficiencies of the systems as proof of concept for the proposed ideas. PMID:24778588

  5. Fast Readout Architectures for Large Arrays of Digital Pixels: Examples and Applications

    PubMed Central

    Gabrielli, A.

    2014-01-01

    Modern pixel detectors, particularly those designed and constructed for applications and experiments for high-energy physics, are commonly built implementing general readout architectures, not specifically optimized in terms of speed. High-energy physics experiments use bidimensional matrices of sensitive elements located on a silicon die. Sensors are read out via other integrated circuits bump bonded over the sensor dies. The speed of the readout electronics can significantly increase the overall performance of the system, and so here novel forms of readout architectures are studied and described. These circuits have been investigated in terms of speed and are particularly suited for large monolithic, low-pitch pixel detectors. The idea is to have a small simple structure that may be expanded to fit large matrices without affecting the layout complexity of the chip, while maintaining a reasonably high readout speed. The solutions might be applied to devices for applications not only in physics but also to general-purpose pixel detectors whenever online fast data sparsification is required. The paper presents also simulations on the efficiencies of the systems as proof of concept for the proposed ideas. PMID:24778588

  6. EZ-Rhizo: integrated software for the fast and accurate measurement of root system architecture.

    PubMed

    Armengaud, Patrick; Zambaux, Kevin; Hills, Adrian; Sulpice, Ronan; Pattison, Richard J; Blatt, Michael R; Amtmann, Anna

    2009-03-01

    The root system is essential for the growth and development of plants. In addition to anchoring the plant in the ground, it is the site of uptake of water and minerals from the soil. Plant root systems show an astonishing plasticity in their architecture, which allows for optimal exploitation of diverse soil structures and conditions. The signalling pathways that enable plants to sense and respond to changes in soil conditions, in particular nutrient supply, are a topic of intensive research, and root system architecture (RSA) is an important and obvious phenotypic output. At present, the quantitative description of RSA is labour intensive and time consuming, even using the currently available software, and the lack of a fast RSA measuring tool hampers forward and quantitative genetics studies. Here, we describe EZ-Rhizo: a Windows-integrated and semi-automated computer program designed to detect and quantify multiple RSA parameters from plants growing on a solid support medium. The method is non-invasive, enabling the user to follow RSA development over time. We have successfully applied EZ-Rhizo to evaluate natural variation in RSA across 23 Arabidopsis thaliana accessions, and have identified new RSA determinants as a basis for future quantitative trait locus (QTL) analysis. PMID:19000163

  7. Ocean observing satellite study: instrument and satellite constellation architecture options

    NASA Technical Reports Server (NTRS)

    Gerber, A. J.; McGuire, J.; Cunningham, J. D.; Pichel, W. G.

    2002-01-01

    This paper provides: (1) an overview of the set of active and passive instruments identified by the IPO designed to make the ocean measurements including visible and infrared medium and high resolution imagers, radiometers, altimeters, and synthetic aperture radars and (2) the instrument and satellite constellation architecture options studied, and their ability to meet the set of measurement requirements.

  8. Observation of Hot Remnant Islands using Fast Thomson Scattering

    NASA Astrophysics Data System (ADS)

    Morton, L. A.; Young, W. C.; den Hartog, D. J.; Hegna, C. C.; Parke, E.; Reusch, J. A.; Jacobson, C. M.

    2015-11-01

    The MST Fast Thomson Scattering Laser, operating with repetition rates of up to 100 kHz for up to 25 laser pulses, has allowed direct observation of temperature structures produced by tearing modes rotating at 10 - 20 kHz. A hot spot observed by Fast TS coincides with the O-point of the dominant m/n = 1/6 mode reconstructed by MHD modeling from edge magnetic measurements. The electron thermal conductivity inside the island is estimated from power balance to be 75 m2/s. However, MHD modeling also predicts overlap between the n =6 and n =7 islands, producing chaotic field lines and total loss of the island flux surfaces. Ensemble-averaged data from the slower burst laser (25 kHz for 8 pulses) also indicates overlap between the temperature fluctuations associated with these modes. These temperature fluctuation also exhibits the large higher-harmonic content that characterizes the hot island in the single-shot cases. DEBS finite-beta MHD simulations qualitatively reproduce MST temperature structures in certain cases. This work is supported by the US DoE and the NSF.

  9. Fast camera observations of injected and intrinsic dust in TEXTOR

    NASA Astrophysics Data System (ADS)

    Shalpegin, A.; Vignitchouk, L.; Erofeev, I.; Brochard, F.; Litnovsky, A.; Bozhenkov, S.; Bykov, I.; den Harder, N.; Sergienko, G.

    2015-12-01

    Stereoscopic fast camera observations of pre-characterized carbon and tungsten dust injection in TEXTOR are reported, along with the modelling of tungsten particle trajectories with MIGRAINe. Particle tracking analysis of the video data showed significant differences in dust dynamics: while carbon flakes were prone to agglomeration and explosive destruction, spherical tungsten particles followed quasi-inertial trajectories. Although this inertial nature prevented any validation of the force models used in MIGRAINe, comparisons between the experimental and simulated lifetimes provide a direct evidence of dust temperature overestimation in dust dynamics codes. Furthermore, wide-view observations of the TEXTOR interior revealed the main production mechanism of intrinsic carbon dust, as well as the location of probable dust remobilization sites.

  10. Fast and Statistically Optimal Period Search in Uneven Sampled Observations

    NASA Astrophysics Data System (ADS)

    Schwarzenberg-Czerny, A.

    1996-04-01

    The classical methods for searching for a periodicity in uneven sampled observations suffer from a poor match of the model and true signals and/or use of a statistic with poor properties. We present a new method employing periodic orthogonal polynomials to fit the observations and the analysis of variance (ANOVA) statistic to evaluate the quality of the fit. The orthogonal polynomials constitute a flexible and numerically efficient model of the observations. Among all popular statistics, ANOVA has optimum detection properties as the uniformly most powerful test. Our recurrence algorithm for expansion of the observations into the orthogonal polynomials is fast and numerically stable. The expansion is equivalent to an expansion into Fourier series. Aside from its use of an inefficient statistic, the Lomb-Scargle power spectrum can be considered a special case of our method. Tests of our new method on simulated and real light curves of nonsinusoidal pulsators demonstrate its excellent performance. In particular, dramatic improvements are gained in detection sensitivity and in the damping of alias periods.

  11. Architecture of scalability file system for meteorological observation data storing

    NASA Astrophysics Data System (ADS)

    Botygin, I. A.; Popov, V. N.; Tartakovsky, V. A.; Sherstnev, V. S.

    2015-11-01

    The approach allows to organize distributed storage of large amounts of diverse data in order to further their parallel processing in high performance cluster systems for problems of climatic processes analysis and forecasting. For different classes of data was used the practice of using meta descriptions - like formalism associated with certain categories of resources. Development of a metadata component was made based on an analysis of data of surface meteorological observations, atmosphere vertical sounding, atmosphere wind sounding, weather radar observing, observations from satellites and others. A common set of metadata components was formed for their general description. The structure and content of the main components of a generalized meta descriptions are presented in detail on the example of reporting meteorological observations from land and sea stations.

  12. Fast Emission Estimates in China Constrained by Satellite Observations (Invited)

    NASA Astrophysics Data System (ADS)

    Mijling, B.; van der A, R.

    2013-12-01

    Emission inventories of air pollutants are crucial information for policy makers and form important input data for air quality models. Unfortunately, bottom-up emission inventories, compiled from large quantities of statistical data, are easily outdated for an emerging economy such as China, where rapid economic growth changes emissions accordingly. Alternatively, top-down emission estimates from satellite observations of air constituents have important advantages of being spatial consistent, having high temporal resolution, and enabling emission updates shortly after the satellite data become available. Constraining emissions from concentration measurements is, however, computationally challenging. Within the GlobEmission project of the European Space Agency (ESA) a new algorithm has been developed, specifically designed for fast daily emission estimates of short-lived atmospheric species on a mesoscopic scale (0.25 × 0.25 degree) from satellite observations of column concentrations. The algorithm needs only one forward model run from a chemical transport model to calculate the sensitivity of concentration to emission, using trajectory analysis to account for transport away from the source. By using a Kalman filter in the inverse step, optimal use of the a priori knowledge and the newly observed data is made. We apply the algorithm for NOx emission estimates in East China, using the CHIMERE model together with tropospheric NO2 column retrievals of the OMI and GOME-2 satellite instruments. The observations are used to construct a monthly emission time series, which reveal important emission trends such as the emission reduction measures during the Beijing Olympic Games, and the impact and recovery from the global economic crisis. The algorithm is also able to detect emerging sources (e.g. new power plants) and improve emission information for areas where proxy data are not or badly known (e.g. shipping emissions). The new emission estimates result in a better

  13. Limb Event Brightenings and Fast Ejection Using IRIS Mission Observations

    NASA Astrophysics Data System (ADS)

    Tavabi, E.; Koutchmy, S.; Golub, L.

    2015-10-01

    The Interface Region Imaging Spectrograph (IRIS) of the recently commissioned NASA small explorer mission provides significantly more complete and higher resolution spectral coverage of the dynamical conditions inside the chromosphere and transition region (TR) than has been available ever before. High temporal, spatial (0.3'') and spectral resolution observations from the ultraviolet IRIS spectra near the solar limb reveal high-energy limb event brightenings (LEBs) at low chromospheric heights at about 1 Mm above the limb. They can be characterized as explosive events producing jets. We selected two events showing spectra of a confined eruption just off or near the quiet-Sun limb, the jet part showing obvious moving material with short-duration large Doppler shifts in three directions that were identified as macrospicules on slit-jaw (SJ) images in Si iv and He ii 304 Å. The events were analyzed from a sequence of very close rasters taken near the central meridian and the South Pole limb. We analyzed the processed SJ images and the simultaneously observed fast spectral sequences, which have large Doppler shifts, with a pair of redshifted elements together with a faster blueshifted element from almost the same position. Shifts correspond to velocities of up to 100 km s^{-1} in projection on the plane of the sky. Erupting spicules and macrospicules from these regions are visible in images taken before and after the spectra. The cool low first ionization potential (FIP) element simultaneous line emissions of the Mg ii h and k resonance lines do not clearly show a similar signature because of optical thickness effects, but the Si iv broadband SJ images do. The bidirectional plasma jets ejected from a small reconnection site are interpreted to be the result of coronal loop-loop interactions that lead to reconnection in nearby sites.

  14. State-based scheduling: An architecture for telescope observation scheduling

    NASA Technical Reports Server (NTRS)

    Muscettola, Nicola; Smith, Stephen F.

    1989-01-01

    The applicability of constraint-based scheduling, a methodology previously developed and validated in the domain of factory scheduling, is extended to problem domains that require attendance to a wider range of state-dependent constraints. The problem of constructing and maintaining a short-term observation schedule for the Hubble Space Telescope (HST), which typifies this type of domain is the focus of interest. The nature of the constraints encountered in the HST domain is examined, system requirements are discussed with respect to utilization of a constraint-based scheduling methodology in such domains, and a general framework for state-based scheduling is presented.

  15. Some important observations on fast decoupled load flow algorithm

    SciTech Connect

    Nanda, J.; Kothari, D.P.; Srivastava, S.C.

    1987-05-01

    This letter brings out clearly for the first time the relative importance and weightage of some of the assumptions made by B. Scott and O. Alsac in their fast decoupled load flow (FDLF) algorithm on its convergence property. Results have been obtained for two sample IEEE test systems. The conclusions of this work are envisaged to be of immense practical relevance while developing a fast decoupled load flow program.

  16. Description and Simulation of a Fast Packet Switch Architecture for Communication Satellites

    NASA Technical Reports Server (NTRS)

    Quintana, Jorge A.; Lizanich, Paul J.

    1995-01-01

    The NASA Lewis Research Center has been developing the architecture for a multichannel communications signal processing satellite (MCSPS) as part of a flexible, low-cost meshed-VSAT (very small aperture terminal) network. The MCSPS architecture is based on a multifrequency, time-division-multiple-access (MF-TDMA) uplink and a time-division multiplex (TDM) downlink. There are eight uplink MF-TDMA beams, and eight downlink TDM beams, with eight downlink dwells per beam. The information-switching processor, which decodes, stores, and transmits each packet of user data to the appropriate downlink dwell onboard the satellite, has been fully described by using VHSIC (Very High Speed Integrated-Circuit) Hardware Description Language (VHDL). This VHDL code, which was developed in-house to simulate the information switching processor, showed that the architecture is both feasible and viable. This paper describes a shared-memory-per-beam architecture, its VHDL implementation, and the simulation efforts.

  17. Knowledge-intensive global optimization of Earth observing system architectures: a climate-centric case study

    NASA Astrophysics Data System (ADS)

    Selva, D.

    2014-10-01

    Requirements from the different disciplines of the Earth sciences on satellite missions have become considerably more stringent in the past decade, while budgets in space organizations have not increased to support the implementation of new systems meeting these requirements. At the same time, new technologies such as optical communications, electrical propulsion, nanosatellite technology, and new commercial agents and models such as hosted payloads are now available. The technical and programmatic environment is thus ideal to conduct architectural studies that look with renewed breadth and adequate depth to the myriad of new possible architectures for Earth Observing Systems. Such studies are challenging tasks, since they require formidable amounts of data and expert knowledge in order to be conducted. Indeed, trade-offs between hundreds or thousands of requirements from different disciplines need to be considered, and millions of combinations of instrument technologies and orbits are possible. This paper presents a framework and tool to support the exploration of such large architectural tradespaces. The framework can be seen as a model-based, executable science traceability matrix that can be used to compare the relative value of millions of different possible architectures. It is demonstrated with an operational climate-centric case study. Ultimately, this framework can be used to assess opportunities for international collaboration and look at architectures for a global Earth observing system, including space, air, and ground assets.

  18. Resource Efficient Hardware Architecture for Fast Computation of Running Max/Min Filters

    PubMed Central

    Torres-Huitzil, Cesar

    2013-01-01

    Running max/min filters on rectangular kernels are widely used in many digital signal and image processing applications. Filtering with a k × k kernel requires of k2 − 1 comparisons per sample for a direct implementation; thus, performance scales expensively with the kernel size k. Faster computations can be achieved by kernel decomposition and using constant time one-dimensional algorithms on custom hardware. This paper presents a hardware architecture for real-time computation of running max/min filters based on the van Herk/Gil-Werman (HGW) algorithm. The proposed architecture design uses less computation and memory resources than previously reported architectures when targeted to Field Programmable Gate Array (FPGA) devices. Implementation results show that the architecture is able to compute max/min filters, on 1024 × 1024 images with up to 255 × 255 kernels, in around 8.4 milliseconds, 120 frames per second, at a clock frequency of 250 MHz. The implementation is highly scalable for the kernel size with good performance/area tradeoff suitable for embedded applications. The applicability of the architecture is shown for local adaptive image thresholding. PMID:24288456

  19. Resource efficient hardware architecture for fast computation of running max/min filters.

    PubMed

    Torres-Huitzil, Cesar

    2013-01-01

    Running max/min filters on rectangular kernels are widely used in many digital signal and image processing applications. Filtering with a k × k kernel requires of k(2) - 1 comparisons per sample for a direct implementation; thus, performance scales expensively with the kernel size k. Faster computations can be achieved by kernel decomposition and using constant time one-dimensional algorithms on custom hardware. This paper presents a hardware architecture for real-time computation of running max/min filters based on the van Herk/Gil-Werman (HGW) algorithm. The proposed architecture design uses less computation and memory resources than previously reported architectures when targeted to Field Programmable Gate Array (FPGA) devices. Implementation results show that the architecture is able to compute max/min filters, on 1024 × 1024 images with up to 255 × 255 kernels, in around 8.4 milliseconds, 120 frames per second, at a clock frequency of 250 MHz. The implementation is highly scalable for the kernel size with good performance/area tradeoff suitable for embedded applications. The applicability of the architecture is shown for local adaptive image thresholding. PMID:24288456

  20. Forward-Projection Architecture for Fast Iterative Image Reconstruction in X-ray CT

    PubMed Central

    Kim, Jung Kuk; Fessler, Jeffrey A.; Zhang, Zhengya

    2012-01-01

    Iterative image reconstruction can dramatically improve the image quality in X-ray computed tomography (CT), but the computation involves iterative steps of 3D forward- and back-projection, which impedes routine clinical use. To accelerate forward-projection, we analyze the CT geometry to identify the intrinsic parallelism and data access sequence for a highly parallel hardware architecture. To improve the efficiency of this architecture, we propose a water-filling buffer to remove pipeline stalls, and an out-of-order sectored processing to reduce the off-chip memory access by up to three orders of magnitude. We make a floating-point to fixed-point conversion based on numerical simulations and demonstrate comparable image quality at a much lower implementation cost. As a proof of concept, a 5-stage fully pipelined, 55-way parallel separable-footprint forward-projector is prototyped on a Xilinx Virtex-5 FPGA for a throughput of 925.8 million voxel projections/s at 200 MHz clock frequency, 4.6 times higher than an optimized 16-threaded program running on an 8-core 2.8-GHz CPU. A similar architecture can be applied to back-projection for a complete iterative image reconstruction system. The proposed algorithm and architecture can also be applied to hardware platforms such as graphics processing unit and digital signal processor to achieve significant accelerations. PMID:23087589

  1. Forward-Projection Architecture for Fast Iterative Image Reconstruction in X-ray CT.

    PubMed

    Kim, Jung Kuk; Fessler, Jeffrey A; Zhang, Zhengya

    2012-10-01

    Iterative image reconstruction can dramatically improve the image quality in X-ray computed tomography (CT), but the computation involves iterative steps of 3D forward- and back-projection, which impedes routine clinical use. To accelerate forward-projection, we analyze the CT geometry to identify the intrinsic parallelism and data access sequence for a highly parallel hardware architecture. To improve the efficiency of this architecture, we propose a water-filling buffer to remove pipeline stalls, and an out-of-order sectored processing to reduce the off-chip memory access by up to three orders of magnitude. We make a floating-point to fixed-point conversion based on numerical simulations and demonstrate comparable image quality at a much lower implementation cost. As a proof of concept, a 5-stage fully pipelined, 55-way parallel separable-footprint forward-projector is prototyped on a Xilinx Virtex-5 FPGA for a throughput of 925.8 million voxel projections/s at 200 MHz clock frequency, 4.6 times higher than an optimized 16-threaded program running on an 8-core 2.8-GHz CPU. A similar architecture can be applied to back-projection for a complete iterative image reconstruction system. The proposed algorithm and architecture can also be applied to hardware platforms such as graphics processing unit and digital signal processor to achieve significant accelerations. PMID:23087589

  2. Geochemistry at 4 Vesta: Observations Using Fast Neutrons

    NASA Technical Reports Server (NTRS)

    Lawrence, David J.; Prettyman, Thomas H.; Feldman, William C.; Bazell, David; Mittlefehldt, David W.; Peplowski, Patrick N.; Reedy, Robert C.

    2012-01-01

    Dawn is currently in orbit around the asteroid 4 Vesta, and one of the major objectives of the mission is to probe the relationship of Vesta to the Howardite, Eucrite, and Diogenite (HED) meteorites. As Vesta is an example of a differentiated planetary embryo, Dawn will also provide fundamental information about planetary evolution in the early solar system [1]. To help accomplish this overall goal, the Dawn spacecraft carries the Gamma-Ray and Neutron Detector (GRaND). GRaND uses planetary gamma-ray and neutron spectroscopy to measure the surface elemental composition of Vesta and will provide information that is unique and complementary to that provided by the other Dawn instruments and investigations. Gamma-ray and neutron spectroscopy is a standard technique for measuring planetary compositions [2], having successfully made measurements at near-Earth asteroids, the Moon, Mars, Mercury and now Vesta. GRaND has made the first measurements of the neutron spectrum from any asteroid (previous asteroid measurements were only made with gamma-rays). Dawn has been collecting data at Vesta since July 2011. The prime data collection period for GRaND is the Low-Altitude Mapping Orbit (LAMO), which started on 12 December 2011 and will last through spring 2012. During LAMO, the Dawn spacecraft orbits at an average altitude of 210 km above the surface of Vesta, which allows good neutron and gamma-ray signals to be detected from Vesta. A description of the overall goals of GRaND and a summary of the initial findings are given elsewhere [3,4]. The subject of this study is to present the information that will be returned from GRaND using fast neutron measurements. Here, we discuss what fast neutrons can reveal about Vesta s surface composition, how such data can address Dawn science goals, and describe fast neutron measurements made in the early portion of the Vesta LAMO phase.

  3. Development of a structured observational method for the systematic assessment of school food-choice architecture.

    PubMed

    Ozturk, Orgul D; McInnes, Melayne M; Blake, Christine E; Frongillo, Edward A; Jones, Sonya J

    2016-01-01

    The objective of this study is to develop a structured observational method for the systematic assessment of the food-choice architecture that can be used to identify key points for behavioral economic intervention intended to improve the health quality of children's diets. We use an ethnographic approach with observations at twelve elementary schools to construct our survey instrument. Elements of the structured observational method include decision environment, salience, accessibility/convenience, defaults/verbal prompts, number of choices, serving ware/method/packaging, and social/physical eating environment. Our survey reveals important "nudgeable" components of the elementary school food-choice architecture, including precommitment and default options on the lunch line. PMID:26654767

  4. Ultra-fast data-mining hardware architecture based on stochastic computing.

    PubMed

    Morro, Antoni; Canals, Vincent; Oliver, Antoni; Alomar, Miquel L; Rossello, Josep L

    2015-01-01

    Minimal hardware implementations able to cope with the processing of large amounts of data in reasonable times are highly desired in our information-driven society. In this work we review the application of stochastic computing to probabilistic-based pattern-recognition analysis of huge database sets. The proposed technique consists in the hardware implementation of a parallel architecture implementing a similarity search of data with respect to different pre-stored categories. We design pulse-based stochastic-logic blocks to obtain an efficient pattern recognition system. The proposed architecture speeds up the screening process of huge databases by a factor of 7 when compared to a conventional digital implementation using the same hardware area. PMID:25955274

  5. Ultra-Fast Data-Mining Hardware Architecture Based on Stochastic Computing

    PubMed Central

    Oliver, Antoni; Alomar, Miquel L.

    2015-01-01

    Minimal hardware implementations able to cope with the processing of large amounts of data in reasonable times are highly desired in our information-driven society. In this work we review the application of stochastic computing to probabilistic-based pattern-recognition analysis of huge database sets. The proposed technique consists in the hardware implementation of a parallel architecture implementing a similarity search of data with respect to different pre-stored categories. We design pulse-based stochastic-logic blocks to obtain an efficient pattern recognition system. The proposed architecture speeds up the screening process of huge databases by a factor of 7 when compared to a conventional digital implementation using the same hardware area. PMID:25955274

  6. A fast algorithm for parallel computation of multibody dynamics on MIMD parallel architectures

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Kwan, Gregory; Bagherzadeh, Nader

    1993-01-01

    In this paper the implementation of a parallel O(LogN) algorithm for computation of rigid multibody dynamics on a Hypercube MIMD parallel architecture is presented. To our knowledge, this is the first algorithm that achieves the time lower bound of O(LogN) by using an optimal number of O(N) processors. However, in addition to its theoretical significance, the algorithm is also highly efficient for practical implementation on commercially available MIMD parallel architectures due to its highly coarse grain size and simple communication and synchronization requirements. We present a multilevel parallel computation strategy for implementation of the algorithm on a Hypercube. This strategy allows the exploitation of parallelism at several computational levels as well as maximum overlapping of computation and communication to increase the performance of parallel computation.

  7. A fast, programmable hardware architecture for the processing of spaceborne SAR data

    NASA Technical Reports Server (NTRS)

    Bennett, J. R.; Cumming, I. G.; Lim, J.; Wedding, R. M.

    1984-01-01

    The development of high-throughput SAR processors (HTSPs) for the spaceborne SARs being planned by NASA, ESA, DFVLR, NASDA, and the Canadian Radarsat Project is discussed. The basic parameters and data-processing requirements of the SARs are listed in tables, and the principal problems are identified as real-operations rates in excess of 2 x 10 to the 9th/sec, I/O rates in excess of 8 x 10 to the 6th samples/sec, and control computation loads (as for range cell migration correction) as high as 1.4 x 10 to the 6th instructions/sec. A number of possible HTSP architectures are reviewed; host/array-processor (H/AP) and distributed-control/data-path (DCDP) architectures are examined in detail and illustrated with block diagrams; and a cost/speed comparison of these two architectures is presented. The H/AP approach is found to be adequate and economical for speeds below 1/200 of real time, while DCDP is more cost-effective above 1/50 of real time.

  8. A Lean, Fast Mars Round-trip Mission Architecture: Using Current Technologies for a Human Mission in the 2030s

    NASA Technical Reports Server (NTRS)

    Bailey, Lora; Folta, David; Barbee, Brent W.; Vaughn, Frank; Kirchman, Frank; Englander, Jacob; Campbell, Bruce; Thronson, Harley; Lin, Tzu Yu

    2013-01-01

    We present a lean fast-transfer architecture concept for a first human mission to Mars that utilizes current technologies and two pivotal parameters: an end-to-end Mars mission duration of approximately one year, and a deep space habitat of approximately 50 metric tons. These parameters were formulated by a 2012 deep space habitat study conducted at the NASA Johnson Space Center (JSC) that focused on a subset of recognized high- engineering-risk factors that may otherwise limit space travel to destinations such as Mars or near-Earth asteroid (NEA)s. With these constraints, we model and promote Mars mission opportunities in the 2030s enabled by a combination of on-orbit staging, mission element pre-positioning, and unique round-trip trajectories identified by state-of-the-art astrodynamics algorithms.

  9. Computer architecture providing high-performance and low-cost solutions for fast fMRI reconstruction

    NASA Astrophysics Data System (ADS)

    Chao, Hui; Goddard, J. Iain

    1998-07-01

    Due to the dynamic nature of brain studies in functional magnetic resonance imaging (fMRI), fast pulse sequences such as echo planar imaging (EPI) and spiral are often used for higher temporal resolution. Hundreds of frames of two- dimensional (2-D) images or multiple three-dimensional (3-D) images are often acquired to cover a larger space and time range. Therefore, fMRI often requires a much larger data storage, faster data transfer rate and higher processing power than conventional MRI. In Mercury Computer Systems' PCI-based embedded computer system, the computer architecture allows the concurrent use of a DMA engine for data transfer and CPU for data processing. This architecture allows a multicomputer to distribute processing and data with minimal time spent transferring data. Different types and numbers of processors are available to optimize system performance for the application. The fMRI reconstruction was first implemented in Mercury's PCI-based embedded computer system by using one digital signal processing (DSP) chip, with the host computer running under the Windows NTR platform. Double buffers in SRAM or cache were created for concurrent I/O and processing. The fMRI reconstruction was then implemented in parallel using multiple DSP chips. Data transfer and interprocessor synchronization were carefully managed to optimize algorithm efficiency. The image reconstruction times were measured with different numbers of processors ranging from one to 10. With one DSP chip, the timing for reconstructing 100 fMRI images measuring 128 X 64 pixels was 1.24 seconds, which is already faster than most existing commercial MRI systems. This PCI-based embedded multicomputer architecture, which has a nearly linear improvement in performance, provides high performance for fMRI processing. In summary, this embedded multicomputer system allows the choice of computer topologies to fit the specific application to achieve maximum system performance.

  10. Attitude determination using vector observations: A fast optimal matrix algorithm

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis

    1993-01-01

    The attitude matrix minimizing Wahba's loss function is computed directly by a method that is competitive with the fastest known algorithm for finding this optimal estimate. The method also provides an estimate of the attitude error covariance matrix. Analysis of the special case of two vector observations identifies those cases for which the TRIAD or algebraic method minimizes Wahba's loss function.

  11. Optical observations of the fast nova V2491 Cyg

    NASA Astrophysics Data System (ADS)

    Tomov, T.; Mikolajewski, M.; Ragan, E.; Swierczynski, E.; Wychudzki, P.

    2008-04-01

    We report on optical spectral observations and UBVRI brightness estimations obtained with 60/90 cm Schmidt and 60 cm Cassegrain telescopes of the Nicolaus Copernicus University Observatory (Torun, Poland). The nova V2491 Cyg was discovered on Apr. 10.728 UT with about 7.7 mag on unfiltered CCD frames (IAUC#8934). Additionally, the X-ray emission was detected for the prenova several months ago (ATel#1473).

  12. Optoelectronic analogs of self-programming neural nets - Architecture and methodologies for implementing fast stochastic learning by simulated annealing

    NASA Technical Reports Server (NTRS)

    Farhat, Nabil H.

    1987-01-01

    Self-organization and learning is a distinctive feature of neural nets and processors that sets them apart from conventional approaches to signal processing. It leads to self-programmability which alleviates the problem of programming complexity in artificial neural nets. In this paper architectures for partitioning an optoelectronic analog of a neural net into distinct layers with prescribed interconnectivity pattern to enable stochastic learning by simulated annealing in the context of a Boltzmann machine are presented. Stochastic learning is of interest because of its relevance to the role of noise in biological neural nets. Practical considerations and methodologies for appreciably accelerating stochastic learning in such a multilayered net are described. These include the use of parallel optical computing of the global energy of the net, the use of fast nonvolatile programmable spatial light modulators to realize fast plasticity, optical generation of random number arrays, and an adaptive noisy thresholding scheme that also makes stochastic learning more biologically plausible. The findings reported predict optoelectronic chips that can be used in the realization of optical learning machines.

  13. Optical emission spectroscopy observations of fast pulsed capillary discharge plasmas

    NASA Astrophysics Data System (ADS)

    Avaria, G.; Ruiz, M.; Guzmán, F.; Favre, M.; Wyndham, E. S.; Chuaqui, H.; Bhuyan, H.

    2014-05-01

    We present time resolved optical emission spectroscopic (OES) observations of a low energy, pulsed capillary discharage (PCD). The optical emission from the capillary plasma and plasma jets emitted from the capillary volume was recorded with with a SpectraPro 275 spectrograph, fitted with a MCP gated OMA system, with 15 ns time resolution. The discharge was operated with different gases, including argon, nitrogen, hydrogen and methane, in a repetitive pulsed discharge mode at 10-50 Hz, with, 10-12 kV pulses applied at the cathode side. The time evolution of the electron density was measured using Stark broadening of the Hβ line. Several features of the capillary plasma dynamics, such as ionization growth, wall effects and plasma jet evolution, are inferred from the time evolution of the optical emission.

  14. Fast AdaBoost-Based Face Detection System on a Dynamically Coarse Grain Reconfigurable Architecture

    NASA Astrophysics Data System (ADS)

    Xiao, Jian; Zhang, Jinguo; Zhu, Min; Yang, Jun; Shi, Longxing

    An AdaBoost-based face detection system is proposed, on a Coarse Grain Reconfigurable Architecture (CGRA) named “REMUS-II”. Our work is quite distinguished from previous ones in three aspects. First, a new hardware-software partition method is proposed and the whole face detection system is divided into several parallel tasks implemented on two Reconfigurable Processing Units (RPU) and one micro Processors Unit (µPU) according to their relationships. These tasks communicate with each other by a mailbox mechanism. Second, a strong classifier is treated as a smallest phase of the detection system, and every phase needs to be executed by these tasks in order. A phase of Haar classifier is dynamically mapped onto a Reconfigurable Cell Array (RCA) only when needed, and it's quite different from traditional Field Programmable Gate Array (FPGA) methods in which all the classifiers are fabricated statically. Third, optimized data and configuration word pre-fetch mechanisms are employed to improve the whole system performance. Implementation results show that our approach under 200MHz clock rate can process up-to 17 frames per second on VGA size images, and the detection rate is over 95%. Our system consumes 194mW, and the die size of fabricated chip is 23mm2 using TSMC 65nm standard cell based technology. To the best of our knowledge, this work is the first implementation of the cascade Haar classifier algorithm on a dynamically CGRA platform presented in the literature.

  15. Orion Flight Test 1 Architecture: Observed Benefits of a Model Based Engineering Approach

    NASA Technical Reports Server (NTRS)

    Simpson, Kimberly A.; Sindiy, Oleg V.; McVittie, Thomas I.

    2012-01-01

    This paper details how a NASA-led team is using a model-based systems engineering approach to capture, analyze and communicate the end-to-end information system architecture supporting the first unmanned orbital flight of the Orion Multi-Purpose Crew Exploration Vehicle. Along with a brief overview of the approach and its products, the paper focuses on the observed program-level benefits, challenges, and lessons learned; all of which may be applied to improve system engineering tasks for characteristically similarly challenges

  16. IMAGE Observations of Sounder Stimulated and Naturally Occurring Fast Z mode Cavity Noise

    NASA Astrophysics Data System (ADS)

    Sonwalkar, V. S.; Taylor, C.; Reddy, A.

    2015-12-01

    We report first observations of sounder stimulated and naturally occurring fast Z mode (ZM) cavity noise detected by the Radio Plasma Imager (RPI) on the IMAGE satellite. The fast Z mode cavity noise is a banded, structure-less radio emission trapped inside fast Z mode cavities, which are characterized by a minimum (fz,min) in fast Z mode cut-off frequency (fz) along a geomagnetic field line [Gurnett et al., JGR, 1983]. Fast Z mode waves reflect at fz ~ f, where f is the wave frequency. Waves in the frequency range fz,min < f < fz,max, where fz,max is the maximum fz above fz,min altitude, are trapped within the cavity as they bounce back and forth between reflection altitudes (fz ~ f) above and below the fz,min altitude. These trapped waves will be observed by a satellite passing through the cavity. The observed cavity noise lower cutoff is at the local Z mode cut-off frequency (fz,Sat) and the upper cut-off is presumably close to fz,max. The cavity noise is observed typically inside the plasmasphere. Comparison of cavity noise as observed on the plasmagram obtained during active sounding with that observed on the dynamic spectra obtained from the interspersed passive wave measurements indicate that the cavity noise is either stimulated by transmissions from the sounder (RPI) or is of natural origin. The sounder stimulated noise is often accompanied by fast Z mode echoes. The naturally occurring cavity noise is observed on both the plasmagram and the dynamic spectra. We believe the stimulated cavity noise is generated due to scattering from small-scale irregularities of waves transmitted by RPI. One potential candidate for the source of naturally occurring Z mode cavity noise is the ring current electrons that can generate fast ZM waves via higher order cyclotron resonance [Nishimura et al., Earth Planets Space, 2007].

  17. Remote observing from the bottom up: the architecture of the WIYN telescope control system

    NASA Astrophysics Data System (ADS)

    Percival, Jeffrey W.

    1995-06-01

    Remote observing has many definitions, ranging from unattended batch-mode use through simple remote logins to fully faithful off-site observing centers indistinguishable from the on- site telescope control room. There are problems with each of these ideas: batch mode operation, for example, precludes remote interactive target acquisition and remote access to targets of opportunity. Simple remote login suffers from network problems such as full-duplex character latency; shipping screens instead of the underlying data can cause bandwidth problems and interferes with analyzing or archiving data. Brute-force reproduction of the control room requires expensive fiber or satellite connections. The WIYN Telescope control system was designed to be inexpensive to build and inexpensive to maintain. We emphasized the use of standard tools, portable implementations, and network friendliness. These techniques and features are precisely those that underlie a powerful remote observing capability. The WIYN Telescope control system therefore supports remote observing from the very lowest levels, and does so effectively and inexpensively using a carefully planned architecture, standard software and network tools, and innovative methods to ship large digital images over low bandwidth connections such as phone lines. Even before the construction was complete, these techniques proved their value by allowing remote access for the purposes of eavesdropping, troubleshooting, and servo tuning. This paper presents a block diagram and detailed descriptions of the WIYN Telescope control system architecture. Each aspect of the control system is discussed with respect to its contribution to the overall goal of remote observing, including multi-user access, bandwidth conservation, interoperability, and portability.

  18. Trans-ethnic Meta-analysis and Functional Annotation Illuminates the Genetic Architecture of Fasting Glucose and Insulin.

    PubMed

    Liu, Ching-Ti; Raghavan, Sridharan; Maruthur, Nisa; Kabagambe, Edmond Kato; Hong, Jaeyoung; Ng, Maggie C Y; Hivert, Marie-France; Lu, Yingchang; An, Ping; Bentley, Amy R; Drolet, Anne M; Gaulton, Kyle J; Guo, Xiuqing; Armstrong, Loren L; Irvin, Marguerite R; Li, Man; Lipovich, Leonard; Rybin, Denis V; Taylor, Kent D; Agyemang, Charles; Palmer, Nicholette D; Cade, Brian E; Chen, Wei-Min; Dauriz, Marco; Delaney, Joseph A C; Edwards, Todd L; Evans, Daniel S; Evans, Michele K; Lange, Leslie A; Leong, Aaron; Liu, Jingmin; Liu, Yongmei; Nayak, Uma; Patel, Sanjay R; Porneala, Bianca C; Rasmussen-Torvik, Laura J; Snijder, Marieke B; Stallings, Sarah C; Tanaka, Toshiko; Yanek, Lisa R; Zhao, Wei; Becker, Diane M; Bielak, Lawrence F; Biggs, Mary L; Bottinger, Erwin P; Bowden, Donald W; Chen, Guanjie; Correa, Adolfo; Couper, David J; Crawford, Dana C; Cushman, Mary; Eicher, John D; Fornage, Myriam; Franceschini, Nora; Fu, Yi-Ping; Goodarzi, Mark O; Gottesman, Omri; Hara, Kazuo; Harris, Tamara B; Jensen, Richard A; Johnson, Andrew D; Jhun, Min A; Karter, Andrew J; Keller, Margaux F; Kho, Abel N; Kizer, Jorge R; Krauss, Ronald M; Langefeld, Carl D; Li, Xiaohui; Liang, Jingling; Liu, Simin; Lowe, William L; Mosley, Thomas H; North, Kari E; Pacheco, Jennifer A; Peyser, Patricia A; Patrick, Alan L; Rice, Kenneth M; Selvin, Elizabeth; Sims, Mario; Smith, Jennifer A; Tajuddin, Salman M; Vaidya, Dhananjay; Wren, Mary P; Yao, Jie; Zhu, Xiaofeng; Ziegler, Julie T; Zmuda, Joseph M; Zonderman, Alan B; Zwinderman, Aeilko H; Adeyemo, Adebowale; Boerwinkle, Eric; Ferrucci, Luigi; Hayes, M Geoffrey; Kardia, Sharon L R; Miljkovic, Iva; Pankow, James S; Rotimi, Charles N; Sale, Michele M; Wagenknecht, Lynne E; Arnett, Donna K; Chen, Yii-Der Ida; Nalls, Michael A; Province, Michael A; Kao, W H Linda; Siscovick, David S; Psaty, Bruce M; Wilson, James G; Loos, Ruth J F; Dupuis, Josée; Rich, Stephen S; Florez, Jose C; Rotter, Jerome I; Morris, Andrew P; Meigs, James B

    2016-07-01

    Knowledge of the genetic basis of the type 2 diabetes (T2D)-related quantitative traits fasting glucose (FG) and insulin (FI) in African ancestry (AA) individuals has been limited. In non-diabetic subjects of AA (n = 20,209) and European ancestry (EA; n = 57,292), we performed trans-ethnic (AA+EA) fine-mapping of 54 established EA FG or FI loci with detailed functional annotation, assessed their relevance in AA individuals, and sought previously undescribed loci through trans-ethnic (AA+EA) meta-analysis. We narrowed credible sets of variants driving association signals for 22/54 EA-associated loci; 18/22 credible sets overlapped with active islet-specific enhancers or transcription factor (TF) binding sites, and 21/22 contained at least one TF motif. Of the 54 EA-associated loci, 23 were shared between EA and AA. Replication with an additional 10,096 AA individuals identified two previously undescribed FI loci, chrX FAM133A (rs213676) and chr5 PELO (rs6450057). Trans-ethnic analyses with regulatory annotation illuminate the genetic architecture of glycemic traits and suggest gene regulation as a target to advance precision medicine for T2D. Our approach to utilize state-of-the-art functional annotation and implement trans-ethnic association analysis for discovery and fine-mapping offers a framework for further follow-up and characterization of GWAS signals of complex trait loci. PMID:27321945

  19. An Observing Architecture for Synthesis of Multi-platform Observations of Carbon Dioxide over Railroad Valley, NV

    NASA Astrophysics Data System (ADS)

    Iraci, L. T.; Fladeland, M. M.; Loewenstein, M.; Bruegge, C. J.; Bui, T.; Crisp, D.; Gore, W.; Kolyer, R.; kuze, A.; Olsen, E. T.; Olson, R. A.; Podolske, J. R.; Quigley, E. A.; Schiro, K.; Sheffner, E. J.; Tadic, J.; Trias, A. A.; Walker, R. L.; Wunch, D.; Yates, E. L.

    2011-12-01

    While satellite observations of carbon dioxide (CO2) will provide global data over long time periods, airborne and ground-based measurements will continue to reduce uncertainties in the carbon budget by providing additional temporal resolution not possible from sensors in orbit. Here we describe a new greenhouse gas (GHG) measurement program at NASA Ames Research Center which integrates multiple ground-based and airborne data sets. Surface level in-situ CO2 and methane (CH4) data were collected in June 2010 and June 2011 at Railroad Valley, NV (RRV). In addition, two cavity ring-down spectrometers were flown above the RRV playa in 2011: a 10 Hz flux instrument on the SIERRA research UAS, and a 3 Hz flight instrument on the Alpha jet stationed at Moffett Field, CA. These two instruments sampled from the surface (4713 ft msl; 1437 m) up to 25,000 ft (7.6 km) msl, and their results will be integrated for comparison to the column averaged dry air CO2 mole fraction observed from orbit (GOSAT, AIRS). Variations in GHG mixing ratios in the boundary layer over this barren surface were measured as a function of time of day. Initial seasonal comparisons of in-situ vertical profiles to column dry mole fractions will be presented. Future inclusion in this observing architecture of ground-based column measurements using near-infrared spectroscopy as part of the TCCON network will also be discussed.

  20. Observations of fast ion losses due to toroidal Alfven eigenmodes in TFTR

    SciTech Connect

    Darrow, D.S.; Zweben, S.J.; Chang, Z.

    1993-08-01

    In a tokamak, knowledge of the rate of fast ion loss is of importance in determining the energy balance of the discharge. Heating of the discharge may be diminished if losses are significant, since neutral beam ions, ICRF heating tail ions, and alpha particles all heat the plasma and may all be lost through processes which expel fast ions. In addition, a loss of fast ions which is sufficiently intense and localized may damage plasma facing components in the vacuum vessel. For these reasons, knowledge of the fast ion loss mechanisms is desirable. Loss processes for fast ions in a tokamak fit into two broad categories: single particle and collective. Single particle losses are those, such as first orbit loss, which are independent of the number of fast ions present. These have been seen in numerous instances on TFIR with DD fusion products, and are reported elsewhere. Collective losses arise when the fast ion density is sufficient to drive instabilities which then cause loss. The drive can come from {partial_derivative}f{sub fi}/{partial_derivative}{psi} (where f{sub fi} is the fast ion distribution function), {partial_derivative}f{sub fi}/{partial_derivative}E, and resonances. Examples of collective instabilities include the toroidal Alfven eigenmode (TAE), the kinetic ballooning mode, alpha driven sawteeth, alpha driven fishbones, Alfven waves, and ion cyclotron waves. This paper limits itself to the presentation of observations made during what are believed to be TAEs which were excited under two conditions in TFTR: at low field (1.5 T), with neutral beam ions driving the mode, and at intermediate field (3.4 T) with the hydrogen minority ICRF tail ions driving the mode.

  1. Photoelectron fluxes observed by FAST compared with model predictions incorporating SNOE observations of the solar soft X-ray irradiance

    NASA Astrophysics Data System (ADS)

    Bailey, S. M.; Peterson, W. K.; Solomon, S. C.; Carlson, C. W.; McFadden, J. P.

    2001-12-01

    Photoelectrons are those electrons produced when atoms or molecules in the upper atmosphere are photoionized. These electrons carry the excess energy of the photon remaining from the ionization and can have energies up to and greater than 1 keV. Photoelectrons are important in that they play a significant role in the energetics of the upper atmosphere, resulting in ionization, dissociation, and excitation of atoms and molecules. There have been long standing issues with regard to understanding the magnitude of the terrestrial photoelectron flux as models have not been able to reproduce the observations without scaling the solar soft X-ray irradiance by factors of two to four. The Fast Auroral Snapshot (FAST) spacecraft was launched in August of 1996. While its primary goals focus on the study of auroral energetic particles, in January of 1999 it began making low-latitude observations. From measurements by the FAST energetic electron sensor, upward flowing photoelectron fluxes in the energy range of 50 eV to 1 keV have been obtained. These measurements are in agreement with earlier measurements of the terrestrial photoelectron flux. The Student Nitric Oxide Explorer (SNOE) spacecraft was launched in February of 1998. Since then it has been making daily observations of the solar soft X-ray irradiance in bandpasses of 2 - 7, 6 - 19, and 17 - 20 nm. SNOE observes larger values of the solar soft X-ray irradiance than reported by earlier observations or predicted by empirical models; however, the SNOE observations are in agreement with many suggestions of the solar soft X-ray irradiance obtained from geophysical observations such as airglow and electron densities. These irradiance measurements are used in a photoelectron model that includes transport. Observations of photoelectron fluxes for the first solar rotation of 1999 are modeled. The model photoelectron spectra are in good agreement with the observed photoelectron spectra over most of the 50 eV to 1 keV energy

  2. FAST Observations of Acceleration Processes in the Cusp--Evidence for Parallel Electric Fields

    NASA Technical Reports Server (NTRS)

    Pfaff, R. F.. Jr.; Carlson, C.; McFadden, J.; Ergun, R.; Clemmons, J.; Klumpar D.; Strangeway, R.

    1999-01-01

    The existence of precipitating keV ions in the Earth's cusp originating at the magnetosheath provide unique means to test our understanding of particle acceleration and parallel electric fields in the lower altitude acceleration region. On numerous occasions, the FAST (The Fast Auroral Snapshot) spacecraft has encountered the Earth's cusp regions near its apogee of 4175 km which are characterized by their signatures of dispersed keV ion injections. The FAST instruments also reveal a complex microphysics inherent to many, but not all, of the cusp regions encountered by the spacecraft, that include upgoing ion beams and conics, inverted-V electrons, upgoing electron beams, and spikey DC-coupled electric fields and plasma waves. Detailed inspection of the FAST data often show clear modulation of the precipitating magnetosheath ions that indicate that they are affected by local electric potentials. For example, the magnetosheath ion precipitation is sometimes abruptly shut off precisely in regions where downgoing localized inverted-V electrons are observed. Such observations support the existence of a localized process, such as parallel electric fields, above the spacecraft which accelerate the electrons downward and consequently impede the precipitating ion precipitation. Other acceleration events in the cusp are sometimes organized with an apparent cellular structure that suggests Alfven waves or other large-scale phenomena are controlling the localized potentials. We examine several cusp encounters by the FAST satellite where the modulation of energetic session on acceleration particle populations reveals evidence of localized acceleration, most likely by parallel electric fields.

  3. Coastal Ocean Observing Network - Open Source Architecture for Data Management and Web-Based Data Services

    NASA Astrophysics Data System (ADS)

    Pattabhi Rama Rao, E.; Venkat Shesu, R.; Udaya Bhaskar, T. V. S.

    2012-07-01

    The observations from the oceans are the backbone for any kind of operational services, viz. potential fishing zone advisory services, ocean state forecast, storm surges, cyclones, monsoon variability, tsunami, etc. Though it is important to monitor open Ocean, it is equally important to acquire sufficient data in the coastal ocean through coastal ocean observing systems for re-analysis, analysis and forecast of coastal ocean by assimilating different ocean variables, especially sub-surface information; validation of remote sensing data, ocean and atmosphere model/analysis and to understand the processes related to air-sea interaction and ocean physics. Accurate information and forecast of the state of the coastal ocean at different time scales is vital for the wellbeing of the coastal population as well as for the socio-economic development of the country through shipping, offshore oil and energy etc. Considering the importance of ocean observations in terms of understanding our ocean environment and utilize them for operational oceanography, a large number of platforms were deployed in the Indian Ocean including coastal observatories, to acquire data on ocean variables in and around Indian Seas. The coastal observation network includes HF Radars, wave rider buoys, sea level gauges, etc. The surface meteorological and oceanographic data generated by these observing networks are being translated into ocean information services through analysis and modelling. Centralized data management system is a critical component in providing timely delivery of Ocean information and advisory services. In this paper, we describe about the development of open-source architecture for real-time data reception from the coastal observation network, processing, quality control, database generation and web-based data services that includes on-line data visualization and data downloads by various means.

  4. Fast X-ray micro-CT for real-time 4D observation

    NASA Astrophysics Data System (ADS)

    Takano, H.; Yoshida, K.; Tsuji, T.; Koyama, T.; Tsusaka, Y.; Kagoshima, Y.

    2009-09-01

    Fast X-ray computed tomography (CT) system with sub-second order measurement for single CT acquisition has been developed. The system, consisting of a high-speed sample rotation stage and a high-speed X-ray camera, is constructed at synchrotron radiation beamline in order to utilize fully intense X-rays. A time-resolving CT movie (i.e. 4D CT) can be available by operating the fast CT system continuously. Real-time observation of water absorbing process of super-absorbent polymer (SAP) has been successfully performed with the 4D CT operation.

  5. MODELING SUPER-FAST MAGNETOSONIC WAVES OBSERVED BY SDO IN ACTIVE REGION FUNNELS

    SciTech Connect

    Ofman, L.; Liu, W.; Title, A.; Aschwanden, M.

    2011-10-20

    Recently, quasi-periodic, rapidly propagating waves have been observed in extreme ultraviolet by the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) instrument in about 10 flare/coronal mass ejection (CME) events thus far. A typical example is the 2010 August 1 C3.2 flare/CME event that exhibited arc-shaped wave trains propagating in an active region (AR) magnetic funnel with {approx}5% intensity variations at speeds in the range of 1000-2000 km s{sup -1}. The fast temporal cadence and high sensitivity of AIA enabled the detection of these waves. We identify them as fast magnetosonic waves driven quasi-periodically at the base of the flaring region and develop a three-dimensional MHD model of the event. For the initial state we utilize the dipole magnetic field to model the AR and include gravitationally stratified density at coronal temperature. At the coronal base of the AR, we excite the fast magnetosonic wave by periodic velocity pulsations in the photospheric plane confined to a funnel of magnetic field lines. The excited fast magnetosonic waves have similar amplitude, wavelength, and propagation speeds as the observed wave trains. Based on the simulation results, we discuss the possible excitation mechanism of the waves, their dynamical properties, and the use of the observations for coronal MHD seismology.

  6. Hyper fast radiative transfer for the physical retrieval of surface parameters from SEVIRI observations

    NASA Astrophysics Data System (ADS)

    Liuzzi, G.; Masiello, G.; Serio, C.; Blasi, M. G.; Venafra, S.

    2015-09-01

    This paper describes the theoretical aspects of a fast scheme for the physical retrieval of surface temperature and emissivity from SEVIRI data, their implementation and some sample results obtained. The scheme is based on a Kalman Filter approach, which effectively exploits the temporal continuity in the observations of the geostationary Meteosat Second Generation (MSG) platform, on which SEVIRI (Spinning Enhanced Visible and InfraRed Imager) operates. Such scheme embodies in its core a physical retrieval algorithm, which employs an hyper fast radiative transfer code highly customized for this retrieval task. Radiative transfer and its customizations are described in detail. Fastness, accuracy and stability of the code are fully documented for a variety of surface features, showing a peculiar application to the massive Greek forest fires in August 2007.

  7. Multi-wavelength Observations of Fast Infrared Flares from V404 Cygni in 2015

    NASA Astrophysics Data System (ADS)

    Eikenberry, Stephen S.; Dallilar, Yigit; Garner, Alan; Deno Stelter, R.; Gandhi, Poshak; Dhillon, Vik; Littlefair, Stuart; Marsh, Thomas; Fender, Rob P.; Mooley, Kunal

    2016-04-01

    We used the fast photometry mode of our new Canarias InfraRed Camera Experiment (CIRCE) on the 10.4-meter Gran Telescopio Canarias to observe V404 Cyg, a stellar mass black hole binary, on June 25, 2015 during its 2015 outburst. CIRCE provided 10Hz sampling in the Ks-band (2.2 microns) In addition, we obtained simultaneous multi wavelength data from our collaborators: three GHz radio bands from the AMI telescope and three optical/UV bands (u', g', r') from ULTRACAM on the William Herschel 4.2-meter telescope. We identify fast (1-second) IR flares with optical counterparts of varying strength/color, which we argue arise from a relativistic jet outflow. These observations provide important constraints on the emission processes and physical conditions in the jet forming region in V404 Cygni. We will discuss these results as well as their implications for relativistic jet formation around stellar-mass black holes.

  8. Observational constraints on dark energy with a fast varying equation of state

    SciTech Connect

    Felice, Antonio De; Nesseris, Savvas

    2012-05-01

    We place observational constraints on models with the late-time cosmic acceleration based on a number of parametrizations allowing fast transitions for the equation of state of dark energy. In addition to the model of Linder and Huterer where the dark energy equation of state w monotonically grows or decreases in time, we propose two new parametrizations in which w has an extremum. We carry out the likelihood analysis with the three parametrizations by using the observational data of supernovae type Ia, cosmic microwave background, and baryon acoustic oscillations. Although the transient cosmic acceleration models with fast transitions can give rise to the total chi square smaller than that in the Λ-Cold-Dark-Matter (ΛCDM) model, these models are not favored over ΛCDM when one uses the Akaike information criterion which penalizes the extra degrees of freedom present in the parametrizations.

  9. Multi-wavelength Observations of Fast Infrared Flares from V404 Cygni in 2015

    NASA Astrophysics Data System (ADS)

    Dallilar, Yigit; Casella, Piergiorgio; Marsh, Tom; Gandhi, Poshak; Fender, Rob; Littlefair, Stuart; Eikenberry, Steve; Garner, Alan; Stelter, Deno; Dhillon, Vik; Mooley, Kunal

    2016-07-01

    We used the fast photometry mode of our new Canarias InfraRed Camera Experiment (CIRCE) on the 10.4-meter Gran Telescopio Canarias to observe V404 Cyg, a stellar mass black hole binary, on June 25, 2015 during its 2015 outburst. CIRCE provided 10Hz sampling in the Ks-band (2.2 microns) In addition, we obtained simultaneous multi wavelength data from our collaborators: three GHz radio bands from the AMI telescope and three optical/UV bands (u', g', r') from ULTRACAM on the William Herschel 4.2-meter telescope. We identify fast (1-second) IR flares with optical counterparts of varying strength/color, which we argue arise from a relativistic jet outflow. These observations provide important constraints on the emission processes and physical conditions in the jet forming region in V404 Cygni. We will discuss these results as well as their implications for relativistic jet formation around stellar-mass black holes.

  10. A Model-Based Study of On-Board Data Processing Architecture for Balloon-Borne Aurora Observation

    NASA Technical Reports Server (NTRS)

    Lim, Chester

    2011-01-01

    This paper discusses an application of ISAAC design methodology to a balloon-borne payload electronic system for aurora observation. The methodology is composed of two phases, high level design and low level implementation, the focus of this paper is on the high level design. This paper puts the system architecture in the context of a balloon based application but it can be generalized to any airborne/space-borne application. The system architecture includes a front-end detector, its corresponding data processing unit, and a controller. VisualSim has been used to perform modeling and simulations to explore the entire design space, finding optimal solutions that meet system requirements.

  11. MMS Observations of magnetospheric fast ion flows and magnetic dipolarization near the dusk-meridian flank

    NASA Astrophysics Data System (ADS)

    Pollock, Craig; Chen, Li-Jen; Wang, Shan; Torbert, Roy; Russell, Christopher; Reiff, Patricia; Giles, Barbara; Burch, James

    2016-04-01

    The concept of a magnetic dipolarization front propagating earthward through Earth's magnetotail and accompanied by fast earthward ion flows, both as consequences of magnetic reconnection occurring tail-ward of an observation point, is well known. Examples of this phenomenology have recently been referred to as reconnection fronts. It is less common to imagine similar signature sets in contexts other than the imagined noon-midnight magnetotail configuration. Nevertheless, signatures of 800 km/s earthward ion flows were observed contemporaneously with distinct but temporary increases in the GSE-z component of the magnetic field at a geocentric distance of the order of 10 RE, in the vicinity (but somewhat tail-ward) of Earth's equatorial dusk terminator on August 12, 2015. These observations were obtained using the Fast Plasma Investigation (FPI) and the Fields electric fields experiment on NASA's Magnetospheric Multiscale (MMS) mission. Several interesting questions arise as to the nature of the observed plasma and field signatures and their drivers in cases such as this. To what degree are they analogous to the magnetotail reconnection fronts previously alluded to? And, to the degree that they are, what kind of reconnection geometry can we envision as giving rise to these signatures at such a location? We will present sample observations and discuss their significance from this point of view.

  12. Properties of Supergiant Fast X-Ray Transients as Observed by Swift

    NASA Technical Reports Server (NTRS)

    Romano, P.; Vercellone, S.; Krimm, H. A.; Esposito, P.; Cusumano, C.; LaParola, V.; Mangano, V.; Kennea, J. A.; Burrows, D. N.; Pagani, C.; Gehrels, N.

    2011-01-01

    We present the most recent results from our investigation on Supergiant Fast X-ray Transients, a class of High-Mass X-ray Binaries, with a possible counterpart in the gamma-ray energy band. Since 2007 Swift has contributed to this new field by detecting outbursts from these fast transients with the BAT and by following them for days with the XRT. Thus, we demonstrated that while the brightest phase of the outburst only lasts a few hours, further activity is observed at lower fluxes for a remarkably longer time, up to weeks. Furthermore, we have performed several campaigns of intense monitoring with the XRT, assessing the fraction of the time these sources spend in each phase, and their duty cycle of inactivity.

  13. Toward Fast and Accurate Evaluation of Charge On-Site Energies and Transfer Integrals in Supramolecular Architectures Using Linear Constrained Density Functional Theory (CDFT)-Based Methods.

    PubMed

    Ratcliff, Laura E; Grisanti, Luca; Genovese, Luigi; Deutsch, Thierry; Neumann, Tobias; Danilov, Denis; Wenzel, Wolfgang; Beljonne, David; Cornil, Jérôme

    2015-05-12

    A fast and accurate scheme has been developed to evaluate two key molecular parameters (on-site energies and transfer integrals) that govern charge transport in organic supramolecular architecture devices. The scheme is based on a constrained density functional theory (CDFT) approach implemented in the linear-scaling BigDFT code that exploits a wavelet basis set. The method has been applied to model disordered structures generated by force-field simulations. The role of the environment on the transport parameters has been taken into account by building large clusters around the active molecules involved in the charge transfer. PMID:26574411

  14. Fast Variability in Selected Chromospherically Active Dwarf Stars and Observational Equipment for Their Study

    NASA Astrophysics Data System (ADS)

    Bogdanovski, Rumen G.

    2015-06-01

    The observations of variable stars, especially those which show fast changes in their brightness, require high speed and high precision photometry. In order to study events like low amplitude optical oscillations and small scale fluctuations in the light curves, synchronous observations are required. These observations have to be carried out simultaneously at two or more, preferably distant, sites (Romanyuk et al., 2001), which allows the identification and elimination of artifacts produced by the equipment and the atmospheric interferences. In this way the fine structure of the light curve is revealed with a significant certainty. In order to study these events a new high speed time synchronized photometric system had to be designed, which addresses the requirements of the observations of high frequency subtle phenomena during stellar flares. It provides remote automatedand centralized control of the photometric equipment over a computer network,as well as remotemonitoring. Furthermore, some preliminary data processing can be performed at the time the data is obtained.

  15. Effects of Ramadan fasting on cardiovascular risk factors: a prospective observational study

    PubMed Central

    2012-01-01

    Background Previous research has shown that Ramadan fasting has beneficial effects on cardiovascular risk factors, however there are controversies. In the present study, the effect of Ramadan fasting on cardiovascular risk factors has been investigated. Method This is a prospective observational study that was carried out in a group of patients with at least one cardiovascular risk factor (including history of documented previous history of either coronary artery disease (CAD), metabolic syndrome or cerebro-vascular disease in past 10 y). Eighty two volunteers including 38 male and 44 female, aged 29–70 y, mean 54.0 ± 10 y, with a previous history of either coronary artery disease, metabolic syndrome or cerebro-vascular disease were recruited. Subjects attended the metabolic unit after at least 10 h fasting, before and after Ramadan who were been fasting for at least 10 days. A fasting blood sample was obtained, blood pressure was measured and body mass index (BMI) was calculated. Lipids profile, fasting blood sugar (FBS) and insulin, homocysteine (hcy), high-sensitivity C-reactive protein (hs-CRP) and complete blood count (CBC) were analyzed on all blood samples. Results A significant improvement in 10 years coronary heart disease risk (based on Framingham risk score) was found (13.0 ± 8 before Ramadan and 10.8 ±7 after Ramadan, P <0.001, t test).There was a significant higher HDL-c, WBC, RBC and platelet count (PLT), and lower plasma cholesterol, triglycerides, LDL-c, VLDL-c, systolic blood pressure, body mass index and waist circumference after Ramadan (P <0.05, t test). The changes in FBS, insulin,Homeostasis Model Assessment Insulin Resistance (HOMA-IR), hcy, hs-CRP and diastolic blood pressure before and after Ramadan were not significant (P >0.05, t test). Conclusions This study shows a significant improvement in 10 years coronary heart disease risk score and other cardiovascular risk factors such as lipids profile, systolic blood

  16. Fast-mode Coronal Wave Trains Detected by SDO/AIA: Recent Observational Progress

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Downs, Cooper; Ofman, Leon

    2016-05-01

    Quasi-periodic Fast Propagating wave trains (QFPs) are a new observational phenomenon discovered by SDO/AIA in extreme ultraviolet (EUV). They are fast-mode magnetosonic waves, closely related to quasi-periodic pulsations in solar flare emission ranging from radio to X-ray wavelengths. The significance of QFPs lies in their diagnostic potential, because they can provide critical clues to flare energy release and serve as new tools for coronal seismology. In this presentation, we report recent advances in observing QFPs. In particular, using differential emission measure (DEM) inversion, we found clear evidence of heating and cooling cycles that are consistent with alternating compression and rarefaction expected for magnetosonic wave pulses. We also found that different local magnetic and plasma environments can lead to two distinct types of QFPs located in different spatial domains with respect to their accompanying coronal mass ejections (CMEs). Moreover, recent IRIS observations of QFP source regions revealed sawtooth-like flare ribbon motions, indicative of pulsed magnetic reconnection, that are correlated with QFP excitation. More interestingly, from a statistical survey of over 100 QFP events, we found a preferential association with eruptive flares rather than confined flares. We will discuss the implications of these results and the potential roles of QFPs in coronal heating, energy transport, and solar eruptions.

  17. Versatile illumination platform and fast optical switch to give standard observation camera gated active imaging capacity

    NASA Astrophysics Data System (ADS)

    Grasser, R.; Peyronneaudi, Benjamin; Yon, Kevin; Aubry, Marie

    2015-10-01

    CILAS, subsidiary of Airbus Defense and Space, develops, manufactures and sales laser-based optronics equipment for defense and homeland security applications. Part of its activity is related to active systems for threat detection, recognition and identification. Active surveillance and active imaging systems are often required to achieve identification capacity in case for long range observation in adverse conditions. In order to ease the deployment of active imaging systems often complex and expensive, CILAS suggests a new concept. It consists on the association of two apparatus working together. On one side, a patented versatile laser platform enables high peak power laser illumination for long range observation. On the other side, a small camera add-on works as a fast optical switch to select photons with specific time of flight only. The association of the versatile illumination platform and the fast optical switch presents itself as an independent body, so called "flash module", giving to virtually any passive observation systems gated active imaging capacity in NIR and SWIR.

  18. Searching for color variation on fast rotating asteroids with simultaneous V-J observations

    NASA Astrophysics Data System (ADS)

    Polishook, David; Moskovitz, Nicholas

    2016-01-01

    Boulders, rocks and regolith on fast rotating asteroids (<2.5 hours) are modeled to slide towards the equator due to a strong centrifugal force and a low cohesion force. As a result, regions of fresh subsurface material can be exposed. Therefore, we searched for color variation on small and fast rotating asteroids. We describe a novel technique in which the asteroid is simultaneously observed in the visible and near-IR wavelength range. In this technique, brightness changes due to atmospheric extinction effects can be calibrated across the visible and near-IR images. We use V- and J-band filters since the distinction in color between weathered and unweathered surfaces on ordinary chondrite-like bodies is most prominent at these wavelengths and can reach ~25%. To test our method, we observed 3 asteroids with Cerro Tololo's 1.3 m telescope. We find ~5% variation of the mean V-J color, but do not find any clearly repeating color signature through multiple rotations. This suggests that no landslides occurred within the timescale of space weathering, or that Landslides occurred but the exposed patches are too small for the measurements' uncertainty.

  19. Fast multicamera video stitching for underwater wide field-of-view observation

    NASA Astrophysics Data System (ADS)

    Li, Qing-Zhong; Zhang, Yang; Zang, Feng-Ni

    2014-03-01

    Underwater robots equipped with a single forward-looking camera usually have a very limited visual range or field-of-view (FOV) due to the light absorption and scattering effects in the underwater environment, which greatly limit their applications for underwater video-based inspection, navigation, and so on. Although underwater robots using multicamera imaging systems can achieve wide FOV of surroundings, parallax distortion and time-consuming stitching computation are encountered, especially for short-distance observation. To overcome these problems, we present a fast multicamera video-stitching algorithm based on adaptive adjustment of image transformation matrix between adjacent images. The proposed method uses a fast and adaptive optimization algorithm to search the optimal parameters of transformation matrix that can minimize the parallax distortion due to short-distance imaging and maximize the matching degree between adjacent overlapping image areas. The advantage of the proposed stitching method lies in that it avoids the complex and time-consuming computations for feature-point extraction and matching. The experimental results show that the proposed method can construct multicamera-based wide FOV video effectively and meets the real-time requirement of wide FOV video observation for both indoor and underwater scenes.

  20. An explanation for experimental observations of harmonic cyclotron emission induced by fast ions

    SciTech Connect

    Chen, K.R.; Horton, W.; Van Dam, J.W.

    1993-09-01

    An explanation, supported by numerical simulations and analytical theory, is given for the harmonic cyclotron emission induced by fast ions in tokamak plasmas - particular, for the emission observed at low harmonics in deuterium-deuterium md deuterium-tritium experiments in the Joint European Tokamak. We show that the first proton harmonic is one of the highest spectral peaks whereas the first alpha is weak. We also compare the relative spectral amplitudes of different harmonics. Our results axe consistent with the experimental observations. The simulations verify that the instabilities are caused by a weak relativistic mass effect. Simulation that a nonuniform magnetic field leads to no appreciable change in the growth and saturation amplitude of the waves.

  1. Cluster Observations During a Slow Crossing of the Duskside LLBL and Conjugate Observations in the Topside Ionosphere with FAST

    NASA Astrophysics Data System (ADS)

    Lund, E. J.; Farrugia, C. J.; Sandholt, P.; Cowley, S. W.; Mouikis, C. G.; Kistler, L. M.; Moebius, E.; Dunlop, M. W.; Reme, H.; Carlson, C. W.

    2003-12-01

    On 7 December 2000, the Cluster spacecraft were trailing a slowly expanding moagnetopause near dusk, remaining within 1 RE of a model boundary for more than three hours. This orbit allows a detailed probing of the structure of the low latitude boundary layer (LLBL). During this time the IMF trended from south to north, a rotation punctuated by several sharp southward excursions. The aim of the paper is threefold: (1) using twin-satellite observations to find the effect of this IMF behavior on the LLBL; (2) to compare the observations with theoretical predictions of the layered structure of the LLBL and its field-aligned currents (Sonnerup and Siebert, 2003); and (3) to find the ionospheric imprints this boundary layer leaves at FAST altitudes. This work is supported in part by NASA's Living with a Star program. Sonnerup, B.~U.~Ö., and K.~D. Siebert, Theory of the low latitude boundary layer and its coupling to the ionosphere: A tutorial review, in Earth's Low-Latitude Boundary Layer, Geophys. Monogr. Ser., vol.~133, edited by P.~T. Newell and T.~Onsager, p.~13, American Geophysical Union, Washington, DC, 2003.

  2. Very long baseline IPS observations of the solar wind speed in the fast polar streams

    NASA Technical Reports Server (NTRS)

    Rao, A. Pramesh; Ananthakrishnan, S.; Balasubramanian, V.; Coles, William A.

    1995-01-01

    Observations of intensity scintillation (IPS) with two or more spaced antennas have been widely used to measure the solar wind velocity. Such methods are particularly valuable in regions which spacecraft have not yet penetrated, but they are also very useful in improving the spatial temporal sampling of the solar wind, even in regions where spacecraft data are available. The principle of the measurement is to measure the time delay tau(sub d) between the scintillations observed with an antenna baseline b. The velocity estimate is just V = b/tau(sub d). The error in estimation of the time delay delta tau(sub d) is independent of the baseline length, thus the error in the velocity estimate delta V given by delta(V)/V approximately equals to (delta tau(sub d))/tau(sub d) is inversely proportional to tau(sub d) and hence to b. However the use of a long baseline b has a less obvious advantage; it provides a means for separating fast and slow contributions when both are present in the scattering region. Here we will present recent observations made using the large cylinder antenna at Ooty in the Nilgiri Hills of South India, and one of the 45 m dishes of GMRT near Pune in West-Central India. The baseline of 900 km is, by a considerable margin, the longest ever used for IPS and provides excellent velocity resolution. These results compared with the ULYSSES observations and other IPS measurements made closer to the sun with higher frequency instruments such as EISCAT and the VLBA will provide a precise measure of the velocity profile of the fast north-polar stream.

  3. Observation of Critical-Gradient Behavior in Alfvén-Eigenmode-Induced Fast-Ion Transport

    NASA Astrophysics Data System (ADS)

    Collins, C. S.; Heidbrink, W. W.; Austin, M. E.; Kramer, G. J.; Pace, D. C.; Petty, C. C.; Stagner, L.; Van Zeeland, M. A.; White, R. B.; Zhu, Y. B.

    2016-03-01

    Experiments in the DIII-D tokamak show that fast-ion transport suddenly becomes stiff above a critical threshold in the presence of many overlapping small-amplitude Alfvén eigenmodes (AEs). The threshold is phase-space dependent and occurs when particle orbits become stochastic due to resonances with AEs. Above threshold, equilibrium fast-ion density profiles are unchanged despite increased drive, and intermittent fast-ion losses are observed. Fast-ion D α spectroscopy indicates radially localized transport of the copassing population at radii that correspond to the location of midcore AEs. The observation of stiff fast-ion transport suggests that reduced models can be used to effectively predict alpha profiles, beam ion profiles, and losses to aid in the design of optimized scenarios for future burning plasma devices.

  4. Observation of Critical-Gradient Behavior in Alfvén-Eigenmode-Induced Fast-Ion Transport.

    PubMed

    Collins, C S; Heidbrink, W W; Austin, M E; Kramer, G J; Pace, D C; Petty, C C; Stagner, L; Van Zeeland, M A; White, R B; Zhu, Y B

    2016-03-01

    Experiments in the DIII-D tokamak show that fast-ion transport suddenly becomes stiff above a critical threshold in the presence of many overlapping small-amplitude Alfvén eigenmodes (AEs). The threshold is phase-space dependent and occurs when particle orbits become stochastic due to resonances with AEs. Above threshold, equilibrium fast-ion density profiles are unchanged despite increased drive, and intermittent fast-ion losses are observed. Fast-ion Dα spectroscopy indicates radially localized transport of the copassing population at radii that correspond to the location of midcore AEs. The observation of stiff fast-ion transport suggests that reduced models can be used to effectively predict alpha profiles, beam ion profiles, and losses to aid in the design of optimized scenarios for future burning plasma devices. PMID:26991180

  5. Observational and Theoretical Challenges to Wave or Turbulence Accelerations of the Fast Solar Wind

    NASA Technical Reports Server (NTRS)

    Roberts, D. Aaron

    2008-01-01

    We use both observations and theoretical considerations to show that hydromagnetic waves or turbulence cannot produce the acceleration of the fast solar wind and the related heating of the open solar corona. Waves do exist as shown by Hinode and other observations, and can play a role in the differential heating and acceleration of minor ions but their amplitudes are not sufficient to power the wind, as demonstrated by extrapolation of magnetic spectra from Helios and Ulysses observations. Dissipation mechanisms invoked to circumvent this conclusion cannot be effective for a variety of reasons. In particular, turbulence does not play a strong role in the corona as shown by both eclipse observations of coronal striations and theoretical considerations of line-tying to a nonturbulent photosphere, nonlocality of interactions, and the nature of kinetic dissipation. In the absence of wave heating and acceleration, the chromosphere and transition region become the natural source of open coronal energization. We suggest a variant of the velocity filtration approach in which the emergence and complex churning of the magnetic flux in the chromosphere and transition region continuously and ubiquitously produces the nonthermal distributions required. These particles are then released by magnetic carpet reconnection at a wide range of scales and produce the wind as described in kinetic approaches. Since the carpet reconnection is not the main source of the energization of the plasma, there is no expectation of an observable release of energy in nanoflares.

  6. Ultra-Fast Flash Observatory for the observation of early photons from gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Park, I. H.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Connell, P.; Eyles, C.; Grossan, B.; Huang, M.-H. A.; Jeong, S.; Jung, A.; Kim, J. E.; Kim, S.-W.; Lee, J.; Lim, H.; Linder, E. V.; Liu, T.-C.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.; Reglero, V.; Ripa, J.; Rodrigo, J. M.; Smoot, G. F.; Svertilov, S.; Vedenkin, N.; Yashin, I.

    2013-02-01

    One of the least documented and understood aspects of gamma-ray bursts (GRBs) is the rise phase of the optical light curve. The Ultra-Fast Flash Observatory (UFFO) is an effort to address this question through extraordinary opportunities presented by a series of space missions including a small spacecraft observatory. The UFFO is equipped with a fast-response Slewing Mirror Telescope (SMT) that uses a rapidly moving mirror or mirror array to redirect the optical beam rather than slewing the entire spacecraft to aim the optical instrument at the GRB position. The UFFO will probe the early optical rise of GRBs with sub-second response, for the first time, opening a completely new frontier in GRBs and transient studies. Its fast response measurements of the optical emission of dozens of GRBs each year will provide unique probes of the burst mechanism and test the prospect of GRBs as a new standard candle, potentially opening up the z > 10 universe. For the first time we employ a motorized slewing stage in SMT that can point to the event within 1 s after the x-ray trigger provided by the UFFO Burst Alert and Trigger Telescope. These two scientific instruments comprise the UFFO-pathfinder payload, which will be placed onboard the Lomonosov satellite and launched in 2013. The UFFO-pathfinder is the first step of our long-term program of space instruments for rapid-response GRB observations. We describe early photon science, our soon-to-be-launched UFFO-pathfinder hardware and mission, and our next planned mission, the UFFO-100.

  7. Incoherent scatter radar-FAST satellite common volume observations of upflow-to-outflow conversion

    NASA Astrophysics Data System (ADS)

    Sánchez, Ennio R.; StrØmme, Anja

    2014-04-01

    Incoherent scatter radar measurements from the Sondrestrom Research Facility and the European Incoherent Scatter Svalbard radar have been combined with all-sky images, polar convection measurements, and FAST particle and field measurements to quantify the contribution of different magnetosphere-ionosphere coupling processes to the extraction efficiency of ions from the ionosphere. Upflowing ions are traced from their source vertically and horizontally to determine where and when they are likely to intersect the acceleration region observed by FAST. The duration and location of auroral emissions are used to estimate the size and duration of the acceleration region. The upflow-to-outflow efficiency is estimated for three periods of polar cap boundary intensifications and streamers during substorm recovery and steady magnetospheric convection. The extraction efficiency of conics ranges between 0.1%, for the lowest amplitude of broadband extremely low frequency waves, and 5%, for the highest-amplitude waves sampled. Simultaneous measurements of all-sky images and magnetic field-aligned radar measurements show that the most intense ion upflux occurs adjacent to the boundary of intense electron precipitation characteristic of polar cap boundary intensifications and streamers, suggesting that the most efficient acceleration mechanisms couple ionospheric heating at F region altitude with dispersive Alfvén waves that grow from horizontal gradients in electric field and conductivity.

  8. Observations and modelling of fast ice growth in the Tiksi Bay, Laptev Sea

    NASA Astrophysics Data System (ADS)

    Bogorodsky, Petr; Makshtas, Aleksandr; Grubiy, Andrey; Kustov, Vasiliy

    2016-04-01

    Fast ice is one of the main features of sea ice cover in the Laptev Sea. The formation of this immobile ice which occupies up to 30% of the sea area and significantly affects the intensity of air-sea energy exchange in the coastal zones had been investigated during winter 2014-2015 in the Tiksi Bay (Buor-Khaya Gulf). The temperature measurements within sea ice thickness and under-ice sea layer using GeoPrecision thermistor string of 10 sensors together with measurements of snow and ice thicknesses were carried out at the distance of 0.5 km from the shore at the 3.5 m water depth. According to measurements temperature variations qualitatively repeat air temperature variations and, damping with depth, approach to sea water freezing temperature. Vertical temperature distributions allow to recognize snow, ice and water layers by profile inclination in each layer. The temperature profiles within growing ice were quasi-linear, indicating permanence of heat flux inside ice. The linearity of temperature profiles increased during ice growth. For calculations of fast ice evolution one-dimensional thermodynamic model was used. Besides the empirical formulae, based on frost degree-days, developed in 1930th for the Tiksi Bay was applied. Numerical experiments were carried out with constant values of thermal properties of all media and 10 ppt water salinity, as initial condition. The daily average data from Hydrometeorological Observatory Tiksi, located approximately 1 km from the site of ice observations, were used as atmospheric forcing. For the examined area evolutions of ice cover thickness estimated from direct measurements, the thermodynamic model and the empirical formulae were almost identical. The result indicates stability of hydrological and meteorological conditions, determining fast ice growth in the Tiksi Bay during last 75 years. Model simulations showed that in shallow waters the growth of ice thickness is stabilized due to increase of sub-ice water layer

  9. Plasma Distribution in Mercury's Magnetosphere Derived from MESSENGER Magnetometer and Fast Imaging Plasma Spectrometer Observations

    NASA Technical Reports Server (NTRS)

    Korth, Haje; Anderson, Brian J.; Gershman, Daniel J.; Raines, Jim M.; Slavin, James A.; Zurbuchen, Thomas H.; Solomon, Sean C.; McNutt, Ralph L.

    2014-01-01

    We assess the statistical spatial distribution of plasma in Mercury's magnetosphere from observations of magnetic pressure deficits and plasma characteristics by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. The statistical distributions of proton flux and pressure were derived from 10months of Fast Imaging Plasma Spectrometer (FIPS) observations obtained during the orbital phase of the MESSENGER mission. The Magnetometer-derived pressure distributions compare favorably with those deduced from the FIPS observations at locations where depressions in the magnetic field associated with the presence of enhanced plasma pressures are discernible in the Magnetometer data. The magnitudes of the magnetic pressure deficit and the plasma pressure agree on average, although the two measures of plasma pressure may deviate for individual events by as much as a factor of approximately 3. The FIPS distributions provide better statistics in regions where the plasma is more tenuous and reveal an enhanced plasma population near the magnetopause flanks resulting from direct entry of magnetosheath plasma into the low-latitude boundary layer of the magnetosphere. The plasma observations also exhibit a pronounced north-south asymmetry on the nightside, with markedly lower fluxes at low altitudes in the northern hemisphere than at higher altitudes in the south on the same field line. This asymmetry is consistent with particle loss to the southern hemisphere surface during bounce motion in Mercury's offset dipole magnetic field.

  10. Experimental observation of ultrasound fast and slow waves through three-dimensional printed trabecular bone phantoms.

    PubMed

    Mézière, F; Juskova, P; Woittequand, J; Muller, M; Bossy, E; Boistel, Renaud; Malaquin, L; Derode, A

    2016-02-01

    In this paper, ultrasound measurements of 1:1 scale three-dimensional (3D) printed trabecular bone phantoms are reported. The micro-structure of a trabecular horse bone sample was obtained via synchrotron x-ray microtomography, converted to a 3D binary data set, and successfully 3D-printed at scale 1:1. Ultrasound through-transmission experiments were also performed through a highly anisotropic version of this structure, obtained by elongating the digitized structure prior to 3D printing. As in real anisotropic trabecular bone, both the fast and slow waves were observed. This illustrates the potential of stereolithography and the relevance of such bone phantoms for the study of ultrasound propagation in bone. PMID:26936578

  11. Microscopic observation of the tips of fast running cracks in PMMA

    NASA Astrophysics Data System (ADS)

    Zimmermann, C.; Schönert, K.

    ALTHOUGH various theoretical models exist, little experimental data is available on the material behaviour in the ultimate vicinity of the tip of fast running cracks. Using a microscope coupled image converter camera, the tips of cracks running in PMMA (polymethylmethacrylate) at speeds between 250 m s -1 and 680 m s -1 were photographed. Due to the high aperture of the optical set-up, shadow optical effects could be greatly reduced. Thus it was possible to observe the contour of the crack flanks up to the crack tip, revealing the existence of fibrils in between the flanks. Seemingly the appearance of these fibrils is connected with the onset of crack branching. Having the crack pass a microlattice, which had been vapor deposited onto the specimen surface, the displacements around the crack tip could be determined. The recorded plastic zone is of triangular shape. Experimental results are compared with theoretical predictions.

  12. Fast emission estimates in China and South Africa constrained by satellite observations

    NASA Astrophysics Data System (ADS)

    Mijling, Bas; van der A, Ronald

    2013-04-01

    Emission inventories of air pollutants are crucial information for policy makers and form important input data for air quality models. Unfortunately, bottom-up emission inventories, compiled from large quantities of statistical data, are easily outdated for emerging economies such as China and South Africa, where rapid economic growth change emissions accordingly. Alternatively, top-down emission estimates from satellite observations of air constituents have important advantages of being spatial consistent, having high temporal resolution, and enabling emission updates shortly after the satellite data become available. However, constraining emissions from observations of concentrations is computationally challenging. Within the GlobEmission project (part of the Data User Element programme of ESA) a new algorithm has been developed, specifically designed for fast daily emission estimates of short-lived atmospheric species on a mesoscopic scale (0.25 × 0.25 degree) from satellite observations of column concentrations. The algorithm needs only one forward model run from a chemical transport model to calculate the sensitivity of concentration to emission, using trajectory analysis to account for transport away from the source. By using a Kalman filter in the inverse step, optimal use of the a priori knowledge and the newly observed data is made. We apply the algorithm for NOx emission estimates in East China and South Africa, using the CHIMERE chemical transport model together with tropospheric NO2 column retrievals of the OMI and GOME-2 satellite instruments. The observations are used to construct a monthly emission time series, which reveal important emission trends such as the emission reduction measures during the Beijing Olympic Games, and the impact and recovery from the global economic crisis. The algorithm is also able to detect emerging sources (e.g. new power plants) and improve emission information for areas where proxy data are not or badly known (e

  13. Searching for color variation on fast rotating asteroids with simultaneous V-J observations

    NASA Astrophysics Data System (ADS)

    Polishook, David; Moskovitz, Nicholas

    2015-08-01

    Motivation: Boulders, rocks and regolith on fast rotating asteroids (~2.5 hours) might slide towards the equator due to a strong centrifugal force and a low cohesion force, as described by models (Walsh et al. 2008, Sánchez & Scheeres 2014). As a result, a fresh material might be exposed, if the surface consists of weathered ordinary chondrite (S-complex). Detecting color variation, due to the exposure of fresh material, will allow us to model the mass shedding process, its extent and age, and thus support or reject hypotheses of rotational-fission.Method: Detecting color variation on small and fast rotating asteroids is difficult with spectroscopy since color differences are mild while the exposure time must be short to measure a narrow rotational phase. Broadband photometry is also problematic since it introduces large systematic errors when images in different filters are calibrated with standard stars. We describe a novel technique in which the asteroid is simultaneously observed in the visible and near-IR wavelength ranges. This technique is possible if a dichroic split the light into two beams that hit two detectors. In this technique atmospheric interference are self-calibrated between the visible and the near-IR image. We use a V and a J filters since the distinction between fresh and weathered surfaces are most prominent in these wavelengths and range between 10-20%.Observations: We observed 3 asteroids with CTIO’s 1.3m telescope and ANDICAM detector. The asteroids were observed during 2 rotational cycles to confirm features on the color-curve. There is ~5% variation of the mean color. There are a few measurements with a larger/smaller color in the range of ~10%, but these do not repeat in a second rotation cycle and we cannot confirm them as real. Therefore, we cannot detect fresh colors (as seen on Q-type asteroids) on the surface. This suggests one of the following statements: 1. No landslides occurred within the timescale of space weathering. 2

  14. Healthcare architecture in metamorphosis--observations in Hong Kong's heuristic experience.

    PubMed

    Lai, M

    2001-01-01

    Healthcare Architecture in Hong Kong is in an on-going process of metamorphosis in response to the social, economical and technological developments in the territory. In the process of transformation, universal problems like obsolescence, growth and expansion, and advances in science and technology as well as problems unique to Hong Kong like population growth, scarcity in land supply and high density development all call for special solutions. With the turn of the century, new forces of change have also begun to take shape, and in anticipation of the hyper-turbulent changes ahead, we need to shift our paradigm to allow revolutionary new perspectives and innovate, shape and create the future healing space which is sustainable, adaptable, flexible and humane. PMID:11858009

  15. A fast band-Krylov eigensolver for macromolecular functional motion simulation on multicore architectures and graphics processors

    NASA Astrophysics Data System (ADS)

    Aliaga, José I.; Alonso, Pedro; Badía, José M.; Chacón, Pablo; Davidović, Davor; López-Blanco, José R.; Quintana-Ortí, Enrique S.

    2016-03-01

    We introduce a new iterative Krylov subspace-based eigensolver for the simulation of macromolecular motions on desktop multithreaded platforms equipped with multicore processors and, possibly, a graphics accelerator (GPU). The method consists of two stages, with the original problem first reduced into a simpler band-structured form by means of a high-performance compute-intensive procedure. This is followed by a memory-intensive but low-cost Krylov iteration, which is off-loaded to be computed on the GPU by means of an efficient data-parallel kernel. The experimental results reveal the performance of the new eigensolver. Concretely, when applied to the simulation of macromolecules with a few thousands degrees of freedom and the number of eigenpairs to be computed is small to moderate, the new solver outperforms other methods implemented as part of high-performance numerical linear algebra packages for multithreaded architectures.

  16. SCTPmx: An SCTP Fast Handover Mechanism Using a Single Interface Based on a Cross-Layer Architecture

    NASA Astrophysics Data System (ADS)

    Han, Yunsop; Teraoka, Fumio

    Recently, SCTP is attracting attention to support mobility in the Internet because it does not require additional equipment such as the Home Agent of Mobile IP. This paper focuses on an SCTP fast handover mechanism using a single interface because it is assumed that small mobile devices have a single interface per communication medium such as IEEE802.11b due to hardware limitations. The proposed mechanism called SCTPmx employs a cross layer control information exchange system called LIESto predict handover. LIES was originally designed to achieve network layer fast handover and then it was extended by adding the network layer primitives for efficient interaction among the link layer, the network layer, and the transport layer. Prior to handover, SCTPmx can generate a new address that will be used after handover and can execute duplicate address detection of IPv6. SCTPmx can suppress the delay caused by channel scanning at the link layer by employing selective background scanning mechanism which allows to continue data communication during channel scanning. In addition, SCTPmx can notify the correspondent node of the new address before handover. SCTPmx was implemented on FreeBSD. SCTPmx achieved better than 25 times lower handover latency (100msec) and 2 times higher throughput than previous proposals.

  17. Seismic observations of large-scale deformation at the bottom of fast-moving plates

    NASA Astrophysics Data System (ADS)

    Debayle, Eric; Ricard, Yanick

    2014-05-01

    We present a new tomographic model of azimuthal anisotropy in the upper mantle and discuss in details the geodynamical causes of this anisotropy. Our model improves upon DKP2005 seismic model (Debayle et al., 2005) through a larger dataset (expanded by a factor ~ 4) and a new approach which allows us to better extract fundamental and higher mode information. Our results confirm that on average, azimuthal anisotropy is only significant in the uppermost 200-250 km of the upper mantle where it decreases regularly with depth. We do not see a significant difference in the amplitude of anisotropy beneath fast oceanic plates, slow oceanic plates or continents. The anisotropy projected onto the direction of present plate motion shows a very specific relation with the plate velocity; it peaks in the asthenosphere around 150 km depth, it is very weak for plate velocities smaller than 3 cm yr-1, increases significantly between 3 and 5 cm yr-1, and saturates for plate velocities larger than 5 cm yr-1. Plate-scale present-day deformation is remarkably well and uniformly recorded beneath the fastest moving plates (India, Coco, Nazca, Australia, Philippine Sea and Pacific plates). Beneath slower plates, plate-motion parallel anisotropy is only observed locally, which suggests that the mantle flow below these plates is not controlled by the lithospheric motion (a minimum plate velocity of around 4 cm yr-1 is necessary for a plate to organize the flow in its underlying asthenosphere). The correlation of oceanic anisotropy with the actual plate motion in the shallow lithosphere is very weak. A better correlation is obtained with the fossil accretion velocity recorded by the gradient of local seafloor age. The transition between frozen-in and active anisotropy occurs across the typical age- isotherm that defines the bottom of the thermal lithosphere around 1100 °C. Under fast continents (mostly under Australia and India), the present day velocity orients also the anisotropy in a

  18. Seismic observations of large-scale deformation at the bottom of fast-moving plates

    NASA Astrophysics Data System (ADS)

    Debayle, Eric; Ricard, Yanick

    2013-08-01

    We present a new tomographic model of azimuthal anisotropy in the upper mantle, DR2012, and discuss in details the geodynamical causes of this anisotropy. Our model improves upon DKP2005 seismic model (Debayle et al., 2005) through a larger dataset (expanded by a factor ˜3.7) and a new approach which allows us to better extract fundamental and higher-mode information. Our results confirm that on average, azimuthal anisotropy is only significant in the uppermost 200-250 km of the upper mantle where it decreases regularly with depth. We do not see a significant difference in the amplitude of anisotropy beneath fast oceanic plates, slow oceanic plates or continents. The anisotropy projected onto the direction of present plate motion shows a very specific relation with the plate velocity; it peaks in the asthenosphere around 150 km depth, it is very weak for plate velocities smaller than 3 cm yr, increases significantly between 3 and 5 cm yr, and saturates for plate velocities larger than 5 cm yr. Plate-scale present-day deformation is remarkably well and uniformly recorded beneath the fastest-moving plates (India, Coco, Nazca, Australia, Philippine Sea and Pacific plates). Beneath slower plates, plate-motion parallel anisotropy is only observed locally, which suggests that the mantle flow below these plates is not controlled by the lithospheric motion (a minimum plate velocity of around 4 cm yr is necessary for a plate to organize the flow in its underlying asthenosphere). The correlation of oceanic anisotropy with the actual plate motion in the shallow lithosphere is very weak. A better correlation is obtained with the fossil accretion velocity recorded by the gradient of local seafloor age. The transition between frozen-in and active anisotropy occurs across the typical √{age} isotherm that defines the bottom of the thermal lithosphere around 1100 °C. Under fast continents (mostly under Australia and India), the present-day velocity orients also the anisotropy

  19. The three-dimensional architecture of the notochordal nucleus pulposus: novel observations on cell structures in the canine intervertebral disc

    PubMed Central

    Hunter, Christopher J; Matyas, John R; Duncan, Neil A

    2003-01-01

    Cells from the nucleus pulposus of young (< 2 years) and old (> 5 years) non-chondrodystrophoid dogs were studied using routine histology, confocal laser scanning microscopy and transmission electron microscopy. The architecture of cell structures – from the tissue scale down to subcellular scale – was reported. Clusters of notochordal cells were observed in young nuclei pulposi, ranging from 10 to 426 cells each. These clusters resisted mechanical disruption and showed evidence of cell–cell signalling via gap junctions. Cells (30–40 µm in diameter) within the clusters had a physaliferous appearance, containing numerous large inclusions which ranged from 1 to 20 µm in diameter. The inclusions were surrounded by a dense actin cortex but were not contained by a lipid bilayer. The contents of the inclusions were determined not to be predominantly carbohydrate or neutral lipid as assessed by histochemical staining, but the exact composition of the contents remained uncertain. There were striking differences in the cell architecture of young vs. old nuclei pulposi, with a loss of both cell clusters and physaliferous cells during ageing. These observations demonstrate unique cell structures, which may influence our understanding of the differences between notochordal and chondrocytic cells in the nucleus pulposus. Such differences could have substantial impact upon how we think about development, degeneration and repair of the intervertebral disc. PMID:12713268

  20. Development of GPU-based Monte Carlo code for fast CT imaging dose calculation on CUDA Fermi architecture

    SciTech Connect

    Liu, T.; Du, X.; Ji, W.; Xu, X. G.

    2013-07-01

    This paper describes the development of a Graphics Processing Unit (GPU) accelerated Monte Carlo photon transport code, ARCHER{sub GPU}, to perform CT imaging dose calculations with good accuracy and performance. The code simulates interactions of photons with heterogeneous materials. It contains a detailed CT scanner model and a family of patient phantoms. Several techniques are used to optimize the code for the GPU architecture. In the accuracy and performance test, a 142 kg adult male phantom was selected, and the CT scan protocol involved a whole-body axial scan, 20-mm x-ray beam collimation, 120 kVp and a pitch of 1. A total of 9 x 108 photons were simulated and the absorbed doses to 28 radiosensitive organs/tissues were calculated. The average percentage difference of the results obtained by the general-purpose production code MCNPX and ARCHER{sub GPU} was found to be less than 0.38%, indicating an excellent agreement. The total computation time was found to be 8,689, 139 and 56 minutes for MCNPX, ARCHER{sub CPU} (6-core) and ARCHER{sub GPU}, respectively, indicating a decent speedup. Under a recent grant funding from the NIH, the project aims at developing a Monte Carlo code with the capability of sub-minute CT organ dose calculations. (authors)

  1. A fast SWIR imager for observations of transient features in OH airglow

    NASA Astrophysics Data System (ADS)

    Hannawald, Patrick; Schmidt, Carsten; Wüst, Sabine; Bittner, Michael

    2016-04-01

    Since December 2013 the new imaging system FAIM (Fast Airglow IMager) for the study of smaller-scale features (both in space and time) is in routine operation at the NDMC (Network for the Detection of Mesospheric Change) station at DLR (German Aerospace Center) in Oberpfaffenhofen (48.1° N, 11.3° E).Covering the brightest OH vibrational bands between 1 and 1.7 µm, this imaging system can acquire two frames per second. The field of view is approximately 55 km times 60 km at the mesopause heights. A mean spatial resolution of 200 m at a zenith angle of 45° and up to 120 m for zenith conditions are achieved. The observations show a large variety of atmospheric waves.This paper introduces the instrument and compares the FAIM data with spectrally resolved GRIPS (GRound-based Infrared P-branch Spectrometer) data. In addition, a case study of a breaking gravity wave event, which we assume to be associated with Kelvin-Helmholtz instabilities, is discussed.

  2. A state observer for using a slow camera as a sensor for fast control applications

    NASA Astrophysics Data System (ADS)

    Gahleitner, Reinhard; Schagerl, Martin

    2013-03-01

    This contribution concerns about a problem that often arises in vision based control, when a camera is used as a sensor for fast control applications, or more precisely, when the sample rate of the control loop is higher than the frame rate of the camera. In control applications for mechanical axes, e.g. in robotics or automated production, a camera and some image processing can be used as a sensor to detect positions or angles. The sample time in these applications is typically in the range of a few milliseconds or less and this demands the use of a camera with a high frame rate up to 1000 fps. The presented solution is a special state observer that can work with a slower and therefore cheaper camera to estimate the state variables at the higher sample rate of the control loop. To simplify the image processing for the determination of positions or angles and make it more robust, some LED markers are applied to the plant. Simulation and experimental results show that the concept can be used even if the plant is unstable like the inverted pendulum.

  3. A fast method for quantifying observational selection effects in asteroid surveys

    NASA Astrophysics Data System (ADS)

    Jedicke, Robert; Bolin, Bryce; Granvik, Mikael; Beshore, Ed

    2016-03-01

    We present a fast method to calculate an asteroid survey's 'bias' - essentially a correction factor from the observed number of objects to the actual number in the population. The method builds upon the work of Jedicke and Metcalfe (Jedicke, R., Metcalfe, T.S. [1998]. Icaurs 131, 245-260) and Granvik et al. (Granvik, M., Vaubaillon, J., Jedicke, R. [2012]. Icarus 218, 262-277) and essentially efficiently maps out the phase space of orbit elements that can appear in a field-of-view. It does so by 'integrating' outwards in geocentric distance along a field's boresite from the topocentric location of the survey and calculating the allowable angular elements for each desired combination of semi-major axis, eccentricity and inclination. We then use a contour algorithm to map out the orbit elements that place an object at the edge of the field-of-view. We illustrate the method's application to calculate the bias correction for near Earth Objects detected with the Catalina Sky Survey (Christensen, E. et al. [2012]. AAS/Division for Planetary Sciences Meeting Abstracts, vol. 44, p. 210.13; Larson, S. et al. [1998]. Bulletin of the American Astronomical Society, vol. 30, p. 1037).

  4. Seismic observations of large-scale deformation at the bottom of fast-moving plates

    NASA Astrophysics Data System (ADS)

    Debayle, E.; Ricard, Y. R.

    2012-12-01

    We investigate the global SV-wave azimuthal anisotropy from a new dataset of around 375 000 fundamental and higher mode Rayleigh waveforms. Our azimuthal anisotropy model improves upon DKP2005 seismic model (Debayle et al., Nature 2005) through a larger dataset (expanded by a factor 3.8) and a new approach which allows us to better extract fundamental and higher mode information. Our results confirm that in average, azimuthal anisotropy is significant only in the uppermost 200-250 km of the upper mantle and weak below. A clear root square of age dependence of anisotropy is observed beneath oceanic plates. The anisotropy projected in the direction of plate motion is more or less proportional to the plate velocity. Plate-scale present-day deformation is remarkably well recorded beneath the fastest moving plates (Indo-Australian, Coco, Nazca, Philippine Sea and Pacific plates). Under these plates, the amplitude of anisotropy does not change much with the distance to the ridge, indicating that the lattice preferred orientation rotates and saturates quickly. Beneath slower plates, plate-motion parallel anisotropy is observed only locally, which suggests, not surprisingly that the convection flow is only partly controlled by the surface motion. Within the lithosphere itself, the anisotropy is weak and likely frozen in; rather aligned with the plate velocity at its age of formation which is recorded by the local age gradient, than with the present-day motion. Although for young ages, the difference between the velocity recorded by the isochrons and the present-day velocity is small, for ages larger than 80 ~myrs the anisotropy rotates with depth from the fossil direction in the lithosphere to the present-day direction in the asthenosphere. Under fast continents (mostly Australia and India), the present day velocity orients the anisotropy around 150-200 km depth.

  5. MICA: A fast short-read aligner that takes full advantage of Many Integrated Core Architecture (MIC)

    PubMed Central

    2015-01-01

    Background Short-read aligners have recently gained a lot of speed by exploiting the massive parallelism of GPU. An uprising alterative to GPU is Intel MIC; supercomputers like Tianhe-2, currently top of TOP500, is built with 48,000 MIC boards to offer ~55 PFLOPS. The CPU-like architecture of MIC allows CPU-based software to be parallelized easily; however, the performance is often inferior to GPU counterparts as an MIC card contains only ~60 cores (while a GPU card typically has over a thousand cores). Results To better utilize MIC-enabled computers for NGS data analysis, we developed a new short-read aligner MICA that is optimized in view of MIC's limitation and the extra parallelism inside each MIC core. By utilizing the 512-bit vector units in the MIC and implementing a new seeding strategy, experiments on aligning 150 bp paired-end reads show that MICA using one MIC card is 4.9 times faster than BWA-MEM (using 6 cores of a top-end CPU), and slightly faster than SOAP3-dp (using a GPU). Furthermore, MICA's simplicity allows very efficient scale-up when multiple MIC cards are used in a node (3 cards give a 14.1-fold speedup over BWA-MEM). Summary MICA can be readily used by MIC-enabled supercomputers for production purpose. We have tested MICA on Tianhe-2 with 90 WGS samples (17.47 Tera-bases), which can be aligned in an hour using 400 nodes. MICA has impressive performance even though MIC is only in its initial stage of development. Availability and implementation MICA's source code is freely available at http://sourceforge.net/projects/mica-aligner under GPL v3. Supplementary information Supplementary information is available as "Additional File 1". Datasets are available at www.bio8.cs.hku.hk/dataset/mica. PMID:25952019

  6. STEREO OBSERVATIONS OF FAST MAGNETOSONIC WAVES IN THE EXTENDED SOLAR CORONA ASSOCIATED WITH EIT/EUV WAVES

    SciTech Connect

    Kwon, Ryun-Young; Ofman, Leon; Kramar, Maxim; Olmedo, Oscar; Davila, Joseph M.; Thompson, Barbara J.; Cho, Kyung-Suk

    2013-03-20

    We report white-light observations of a fast magnetosonic wave associated with a coronal mass ejection observed by STEREO/SECCHI/COR1 inner coronagraphs on 2011 August 4. The wave front is observed in the form of density compression passing through various coronal regions such as quiet/active corona, coronal holes, and streamers. Together with measured electron densities determined with STEREO COR1 and Extreme UltraViolet Imager (EUVI) data, we use our kinematic measurements of the wave front to calculate coronal magnetic fields and find that the measured speeds are consistent with characteristic fast magnetosonic speeds in the corona. In addition, the wave front turns out to be the upper coronal counterpart of the EIT wave observed by STEREO EUVI traveling against the solar coronal disk; moreover, stationary fronts of the EIT wave are found to be located at the footpoints of deflected streamers and boundaries of coronal holes, after the wave front in the upper solar corona passes through open magnetic field lines in the streamers. Our findings suggest that the observed EIT wave should be in fact a fast magnetosonic shock/wave traveling in the inhomogeneous solar corona, as part of the fast magnetosonic wave propagating in the extended solar corona.

  7. Volcano-tectonic architecture of a Caldera Complex, Karthala volcano, Grande Comore: new field observations

    NASA Astrophysics Data System (ADS)

    Poppe, S.; Kervyn, M.; Soulé, H.; Cnudde, V.; De Kock, T.; Jacobs, P.

    2012-04-01

    fed small-scale eruptive cones, vertical degassing fissures and former caldera levels. Fissures with active fumaroles inside the two explosive craters and in the area between Choungou Chahalé and Changouméni are indicating a focus area in the hydrothermal activity. It is this hydrothermal system that is suggested to have controlled the phreatic nature of recent eruptions (1991, 2005 and 2007). Several pyroclastic beds and cones affected by block and bomb impacts inside the caldera complex and around the summit area testify the high explosive nature of these recent eruptions, in contrast with the effusive Hawaiian-style character generally associated with Karthala. The orientation of caldera-bounding structures, eruption and fumarolic fissures, dykes as well as the orientation of intra-caldera extensional faults indicate one minor (E-W) and two major volcano-tectonic directions (N-S and N135°S). The latter are concurring with previously identified regional stress orientations and rift zone's orientations on Karthala flanks. Upcoming field work will be dedicated to the exhaustive structural and stratigraphic mapping of Karthala caldera as it provides exceptional exposure to document the internal architecture of an alkali basalt shield volcano and a complex caldera subsidence chronology.

  8. Swift observations of two supergiant fast X-ray transient prototypes in outburst

    NASA Astrophysics Data System (ADS)

    Farinelli, R.; Romano, P.; Mangano, V.; Ceccobello, C.; Ducci, L.; Vercellone, S.; Esposito, P.; Kennea, J. A.; Burrows, D. N.

    2012-08-01

    We report on the results from observations of the most recent outbursts of XTE J1739-302 and IGR J17544-2619, which are considered to be the prototypes of the supergiant fast X-ray transient class. They triggered the Swift/Burst Alert Telescope on 2011 February 22 and March 24, respectively, and each time a prompt Swift slew allowed us to obtain the rich broad-band data we present. The X-ray Telescope light curves show the descending portion of very bright flares that reached luminosities of ˜2 × 1036 and ˜5 × 1036 erg s-1. The broad-band spectra, when fitted with the usual phenomenological models adopted for accreting neutron stars, yield values of both high-energy cut-off and e-folding energy consistent with those obtained from previously reported outbursts from these sources. In the context of more physical models, the spectra of both sources can be well fitted either with a two-blackbody model or with a single unsaturated Comptonization model. In the latter case, the model can be either a classical static Comptonization model, such as COMPTT, or the recently developed COMPMAG model, which includes thermal and bulk Comptonization for cylindrical accretion on to a magnetized neutron star. We discuss the possible accretion scenarios derived by the different models, and we also emphasize the fact that the electron density derived from the Comptonization models, in the regions where the X-ray spectrum presumably forms, is lower than that estimated using the continuity equation at the magnetospheric radius and the source X-ray luminosity, and we give some possible explanations.

  9. Elemental and charge state composition of the fast solar wind observed with SMS instruments on WIND

    NASA Technical Reports Server (NTRS)

    Gloeckler, G.; Galvin, A. B.; Ipavich, F. M.; Hamilton, D. C.; Bochsler, P.; Geiss, J.; Fisk, L. A.; Wilken, B.

    1995-01-01

    The elemental composition and charge state distributions of heavy ions of the solar wind provide essential information about: (1) atom-ion separation processes in the solar atmosphere leading to the 'FIP effect' (the overabundance of low First Ionization potential (FIP) elements in the solar wind compared to the photosphere); and (2) coronal temperature profiles, as well as mechanisms which heat the corona and accelerate the solar wind. This information is required for solar wind acceleration models. The SWICS instrument on Ulysses measures for all solar wind flow conditions the relative abundance of about 8 elements and 20 charge states of the solar wind. Furthermore, the Ulysses high-latitude orbit provides an unprecedented look at the solar wind from the polar coronal holes near solar minimum conditions. The MASS instrument on the WIND spacecraft is a high-mass resolution solar wind ion mass spectrometer that will provide routinely not only the abundances and charge state of all elements easily measured with SWICS, but also of N, Mg, S. The MASS sensor was fully operational at the end of 1994 and has sampled the in-ecliptic solar wind composition in both the slow and the corotating fast streams. This unique combination of SWICS on Ulysses and MASS on WIND allows us to view for the first time the solar wind from two regions of the large coronal hole. Observations with SWICS in the coronal hole wind: (1) indicate that the FIP effect is small; and (2) allow us determine the altitude of the maximum in the electron temperature profile, and indicate a maximum temperature of approximately 1.5 MK. New results from the SMS instruments on Wind will be compared with results from SWICS on Ulysses.

  10. Architecture and morphology of coral reef sequences. Modeling and observations from uplifting islands of SE Sulawesi, Indonesia

    NASA Astrophysics Data System (ADS)

    Pastier, Anne-Morwenn; Husson, Laurent; Bezos, Antoine; Pedoja, Kevin; Elliot, Mary; Hafidz, Abdul; Imran, Muhammad; Lacroix, Pascal; Robert, Xavier

    2016-04-01

    During the Late Neogene, sea level oscillations have profoundly shaped the morphology of the coastlines of intertropical zones, wherein relative sea level simultaneously controlled reef expansion and erosion of earlier reef bodies. In uplifted domains like SE Sulawesi, the sequences of fossil reefs display a variety of fossil morphologies. Similarly, the morphologies of the modern reefs are highly variable, including cliff notches, narrow fringing reefs, wide flat terraces, and barriers reefs. In this region, where uplift rates vary rapidly laterally, the entire set of morphologies is displayed within short distances. We developed a numerical model that predicts the architecture of fossil reefs sequences and apply it to observations from SE Sulawesi, accounting -amongst other parameters- for reef growth, coastal erosion, and uplift rates. The observations that we use to calibrate our models are mostly the morphology of both the onshore (dGPS and high-resolution Pleiades DEM) and offshore (sonar) coast, as well as U-Th radiometrically dated coral samples. Our method allows unravelling the spatial and temporal evolution of large domains on map view. Our analysis indicates that the architecture and morphology of uplifting coastlines is almost systematically polyphased (as attested by samples of different ages within a unique terrace), which assigns a primordial role to erosion, comparable to reef growth. Our models also reproduce the variety of modern morphologies, which are chiefly dictated by the uplift rates of the pre-existing morphology of the substratum, itself responding to the joint effects of reef building and subsequent erosion. In turn, we find that fossil and modern morphologies can be returned to uplift rates rather precisely, as the parametric window of each specific morphology is often narrow.

  11. An Architecture and Analysis Environment for Model to Observational Data Intercomparisons

    NASA Astrophysics Data System (ADS)

    Mattmann, C. A.; Williams, D.; Braverman, A. J.; Crichton, D. J.

    2009-12-01

    The Jet Propulsion Laboratory (JPL) has within the last year initiated an effort to increase the use of its observational data in the improvement and analysis of climate model outputs. This effort, known as the Climate Data eXchange (CDX), is a multi-institutional collaboration involving representatives from JPL and from the Program for Climate Model Diagnosis and Intercomparisions (PCMDI) at Lawrence Livermore National Laboratory (LLNL). Our early focus in the context of CDX has been on NASA Level 2 observational data products. These products vary in a number of ways incl.: (1) format - many of the products are stored in the Hierarchical Data Format (HDF), others in netCDF, with variation even between software versions that generated these output files within the same format; (2) geographic distribution - most observational data products are co-located with their scientific discipline expertise, to increase the yield of promising scientific results and to cut down on the effort for a science user to make progress; (3) data access mechanism - some data products are available from sophisticated web service interfaces, e.g., OPeNDAP -- others are not, requiring a user to fill on an online web ordering ``cart'', and have an email notification indicating availability at a later date; and (4) size - depending on the frequency of the instrument's orbit, and the characteristics of the mission including the way that the instrument ``sees'' the Earth, the sheer volume of the Level 2 data can widely vary, ranging from megabytes (MB) per product, to gigabytes (GB). These four dimensions are just a sampling of the characteristics of Level 2 observational data. The goal of CDX is to deliver an open source software toolkit that allows science users to alleviate as much of the complexity of dealing with Level 2 observational data as possible, and to facilitate its comparison to model outputs. In this fashion, there are two fundamental subsystems within CDX: (1) a Client Toolkit

  12. Using compute unified device architecture-enabled graphic processing unit to accelerate fast Fourier transform-based regression Kriging interpolation on a MODIS land surface temperature image

    NASA Astrophysics Data System (ADS)

    Hu, Hongda; Shu, Hong; Hu, Zhiyong; Xu, Jianhui

    2016-04-01

    Kriging interpolation provides the best linear unbiased estimation for unobserved locations, but its heavy computation limits the manageable problem size in practice. To address this issue, an efficient interpolation procedure incorporating the fast Fourier transform (FFT) was developed. Extending this efficient approach, we propose an FFT-based parallel algorithm to accelerate regression Kriging interpolation on an NVIDIA® compute unified device architecture (CUDA)-enabled graphic processing unit (GPU). A high-performance cuFFT library in the CUDA toolkit was introduced to execute computation-intensive FFTs on the GPU, and three time-consuming processes were redesigned as kernel functions and executed on the CUDA cores. A MODIS land surface temperature 8-day image tile at a resolution of 1 km was resampled to create experimental datasets at eight different output resolutions. These datasets were used as the interpolation grids with different sizes in a comparative experiment. Experimental results show that speedup of the FFT-based regression Kriging interpolation accelerated by GPU can exceed 1000 when processing datasets with large grid sizes, as compared to the traditional Kriging interpolation running on the CPU. These results demonstrate that the combination of FFT methods and GPU-based parallel computing techniques greatly improves the computational performance without loss of precision.

  13. Time-resolved observation of fast domain-walls driven by vertical spin currents in short tracks

    NASA Astrophysics Data System (ADS)

    Sampaio, Joao; Lequeux, Steven; Metaxas, Peter J.; Chanthbouala, Andre; Matsumoto, Rie; Yakushiji, Kay; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji; Nishimura, Kazumasa; Nagamine, Yoshinori; Maehara, Hiroki; Tsunekawa, Koji; Cros, Vincent; Grollier, Julie

    2013-12-01

    We present time-resolved measurements of the displacement of magnetic domain-walls (DWs) driven by vertical spin-polarized currents in track-shaped magnetic tunnel junctions. In these structures, we observe very high DW velocities (600 m/s) at current densities below 107 A/cm2. We show that the efficient spin-transfer torque combined with a short propagation distance allows avoiding the Walker breakdown process and achieving deterministic, reversible, and fast (≈1 ns) DW-mediated switching of magnetic tunnel junction elements, which is of great interest for the implementation of fast DW-based spintronic devices.

  14. Time-resolved observation of fast domain-walls driven by vertical spin currents in short tracks

    SciTech Connect

    Sampaio, Joao; Lequeux, Steven; Chanthbouala, Andre; Cros, Vincent; Grollier, Julie; Matsumoto, Rie; Yakushiji, Kay; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji; Nishimura, Kazumasa; Nagamine, Yoshinori; Maehara, Hiroki; Tsunekawa, Koji

    2013-12-09

    We present time-resolved measurements of the displacement of magnetic domain-walls (DWs) driven by vertical spin-polarized currents in track-shaped magnetic tunnel junctions. In these structures, we observe very high DW velocities (600 m/s) at current densities below 10{sup 7} A/cm{sup 2}. We show that the efficient spin-transfer torque combined with a short propagation distance allows avoiding the Walker breakdown process and achieving deterministic, reversible, and fast (≈1 ns) DW-mediated switching of magnetic tunnel junction elements, which is of great interest for the implementation of fast DW-based spintronic devices.

  15. Geopotential Error Analysis from Satellite Gradiometer and Global Positioning System Observables on Parallel Architecture

    NASA Technical Reports Server (NTRS)

    Schutz, Bob E.; Baker, Gregory A.

    1997-01-01

    The recovery of a high resolution geopotential from satellite gradiometer observations motivates the examination of high performance computational techniques. The primary subject matter addresses specifically the use of satellite gradiometer and GPS observations to form and invert the normal matrix associated with a large degree and order geopotential solution. Memory resident and out-of-core parallel linear algebra techniques along with data parallel batch algorithms form the foundation of the least squares application structure. A secondary topic includes the adoption of object oriented programming techniques to enhance modularity and reusability of code. Applications implementing the parallel and object oriented methods successfully calculate the degree variance for a degree and order 110 geopotential solution on 32 processors of the Cray T3E. The memory resident gradiometer application exhibits an overall application performance of 5.4 Gflops, and the out-of-core linear solver exhibits an overall performance of 2.4 Gflops. The combination solution derived from a sun synchronous gradiometer orbit produce average geoid height variances of 17 millimeters.

  16. GLOBAL CORONAL SEISMOLOGY IN THE EXTENDED SOLAR CORONA THROUGH FAST MAGNETOSONIC WAVES OBSERVED BY STEREO SECCHI COR1

    SciTech Connect

    Kwon, Ryun-Young; Kramar, Maxim; Wang, Tongjiang; Ofman, Leon; Davila, Joseph M.; Chae, Jongchul; Zhang, Jie

    2013-10-10

    We present global coronal seismology for the first time, which allows us to determine inhomogeneous magnetic field strength in the extended corona. From the measurements of the propagation speed of a fast magnetosonic wave associated with a coronal mass ejection (CME) and the coronal background density distribution derived from the polarized radiances observed by the STEREO SECCHI COR1, we determined the magnetic field strengths along the trajectories of the wave at different heliocentric distances. We found that the results have an uncertainty less than 40%, and are consistent with values determined with a potential field model and reported in previous works. The characteristics of the coronal medium we found are that (1) the density, magnetic field strength, and plasma β are lower in the coronal hole region than in streamers; (2) the magnetic field strength decreases slowly with height but the electron density decreases rapidly so that the local fast magnetosonic speed increases while plasma β falls off with height; and (3) the variations of the local fast magnetosonic speed and plasma β are dominated by variations in the electron density rather than the magnetic field strength. These results imply that Moreton and EIT waves are downward-reflected fast magnetosonic waves from the upper solar corona, rather than freely propagating fast magnetosonic waves in a certain atmospheric layer. In addition, the azimuthal components of CMEs and the driven waves may play an important role in various manifestations of shocks, such as type II radio bursts and solar energetic particle events.

  17. NASA's Earth Observing Data and Information System - Supporting Interoperability through a Scalable Architecture (Invited)

    NASA Astrophysics Data System (ADS)

    Mitchell, A. E.; Lowe, D. R.; Murphy, K. J.; Ramapriyan, H. K.

    2013-12-01

    Initiated in 1990, NASA's Earth Observing System Data and Information System (EOSDIS) is currently a petabyte-scale archive of data designed to receive, process, distribute and archive several terabytes of science data per day from NASA's Earth science missions. Comprised of 12 discipline specific data centers collocated with centers of science discipline expertise, EOSDIS manages over 6800 data products from many science disciplines and sources. NASA supports global climate change research by providing scalable open application layers to the EOSDIS distributed information framework. This allows many other value-added services to access NASA's vast Earth Science Collection and allows EOSDIS to interoperate with data archives from other domestic and international organizations. EOSDIS is committed to NASA's Data Policy of full and open sharing of Earth science data. As metadata is used in all aspects of NASA's Earth science data lifecycle, EOSDIS provides a spatial and temporal metadata registry and order broker called the EOS Clearing House (ECHO) that allows efficient search and access of cross domain data and services through the Reverb Client and Application Programmer Interfaces (APIs). Another core metadata component of EOSDIS is NASA's Global Change Master Directory (GCMD) which represents more than 25,000 Earth science data set and service descriptions from all over the world, covering subject areas within the Earth and environmental sciences. With inputs from the ECHO, GCMD and Soil Moisture Active Passive (SMAP) mission metadata models, EOSDIS is developing a NASA ISO 19115 Best Practices Convention. Adoption of an international metadata standard enables a far greater level of interoperability among national and international data products. NASA recently concluded a 'Metadata Harmony Study' of EOSDIS metadata capabilities/processes of ECHO and NASA's Global Change Master Directory (GCMD), to evaluate opportunities for improved data access and use, reduce

  18. Consumers’ estimation of calorie content at fast food restaurants: cross sectional observational study

    PubMed Central

    Condon, Suzanne K; Kleinman, Ken; Mullen, Jewel; Linakis, Stephanie; Rifas-Shiman, Sheryl; Gillman, Matthew W

    2013-01-01

    Objective To investigate estimation of calorie (energy) content of meals from fast food restaurants in adults, adolescents, and school age children. Design Cross sectional study of repeated visits to fast food restaurant chains. Setting 89 fast food restaurants in four cities in New England, United States: McDonald’s, Burger King, Subway, Wendy’s, KFC, Dunkin’ Donuts. Participants 1877 adults and 330 school age children visiting restaurants at dinnertime (evening meal) in 2010 and 2011; 1178 adolescents visiting restaurants after school or at lunchtime in 2010 and 2011. Main outcome measure Estimated calorie content of purchased meals. Results Among adults, adolescents, and school age children, the mean actual calorie content of meals was 836 calories (SD 465), 756 calories (SD 455), and 733 calories (SD 359), respectively. A calorie is equivalent to 4.18 kJ. Compared with the actual figures, participants underestimated calorie content by means of 175 calories (95% confidence interval 145 to 205), 259 calories (227 to 291), and 175 calories (108 to 242), respectively. In multivariable linear regression models, underestimation of calorie content increased substantially as the actual meal calorie content increased. Adults and adolescents eating at Subway estimated 20% and 25% lower calorie content than McDonald’s diners (relative change 0.80, 95% confidence interval 0.66 to 0.96; 0.75, 0.57 to 0.99). Conclusions People eating at fast food restaurants underestimate the calorie content of meals, especially large meals. Education of consumers through calorie menu labeling and other outreach efforts might reduce the large degree of underestimation. PMID:23704170

  19. A Web 2.0 and OGC Standards Enabled Sensor Web Architecture for Global Earth Observing System of Systems

    NASA Technical Reports Server (NTRS)

    Mandl, Daniel; Unger, Stephen; Ames, Troy; Frye, Stuart; Chien, Steve; Cappelaere, Pat; Tran, Danny; Derezinski, Linda; Paules, Granville

    2007-01-01

    This paper will describe the progress of a 3 year research award from the NASA Earth Science Technology Office (ESTO) that began October 1, 2006, in response to a NASA Announcement of Research Opportunity on the topic of sensor webs. The key goal of this research is to prototype an interoperable sensor architecture that will enable interoperability between a heterogeneous set of space-based, Unmanned Aerial System (UAS)-based and ground based sensors. Among the key capabilities being pursued is the ability to automatically discover and task the sensors via the Internet and to automatically discover and assemble the necessary science processing algorithms into workflows in order to transform the sensor data into valuable science products. Our first set of sensor web demonstrations will prototype science products useful in managing wildfires and will use such assets as the Earth Observing 1 spacecraft, managed out of NASA/GSFC, a UASbased instrument, managed out of Ames and some automated ground weather stations, managed by the Forest Service. Also, we are collaborating with some of the other ESTO awardees to expand this demonstration and create synergy between our research efforts. Finally, we are making use of Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) suite of standards and some Web 2.0 capabilities to Beverage emerging technologies and standards. This research will demonstrate and validate a path for rapid, low cost sensor integration, which is not tied to a particular system, and thus be able to absorb new assets in an easily evolvable, coordinated manner. This in turn will help to facilitate the United States contribution to the Global Earth Observation System of Systems (GEOSS), as agreed by the U.S. and 60 other countries at the third Earth Observation Summit held in February of 2005.

  20. Direct Electron Heating Observed by Fast Waves in ICRF Range on a Low-Density Low Temperature Tokamak ADITYA

    SciTech Connect

    Mishra, K.; Kulkarni, S.; Rathi, D.; Varia, A.; Jadav, H.; Parmar, K.; Kadia, B.; Joshi, R.; Srinivas, Y.; Singh, R.; Kumar, S.; Dani, S.; Gayatri, A.; Yogi, R.; Singh, M.; Joisa, Y.; Rao, C.; Kumar, S.; Jha, R.; Manchanda, R.

    2011-12-23

    Fast wave electron heating experiments are carried out on Aditya tokamak [R = 0.75 m, a = 0.25m,Bt = 0.75T,ne{approx}1-3E13/cc,Te{approx}250eV] with the help of indigenously developed 200 kW, 20-40 MHz RF heating system. Significant direct electron heating is observed by fast waves in hydrogen plasma with prompt rise in electron temperature with application of RF power and it increases linearly with RF power. A corresponding increase in plasma beta and hence increase in stored diamagnetic energy is also observed in presence of RF. We observe an improvement of energy confinement time from 2-4msec during ohmic heating phase to 3-6msec in RF heating phase. This improvement is within the ohmic confinement regime for the present experiments. The impurity radiation and electron density do not escalate significantly with RF power. The direct electron heating by fast wave in Aditya is also predicted by ion cyclotron resonance heating code TORIC.

  1. An observational study on the influence of solvent composition on the architecture of drug-layered pellets.

    PubMed

    McConnell, Emma L; Macfarlane, Calum B; Basit, Abdul W

    2009-10-01

    Pelletization for the manufacture of modified release multiparticulate drug delivery systems is often considered to be well defined and robust. However, small differences in formulation conditions can lead to surprising changes to the expected outcomes. We observed that extended release tramadol hydrochloride pellets, prepared by solution layering an ethanolic solution of drug on a non-pareil, resulted in highly unusual pellet architecture with deep indentations which prevented the application of a homogeneous outer coating of ethylcellulose and talc, and negatively influenced the desired modified release characteristics. Modification of outer coating thickness and process temperature showed no improvement in release characteristics. A solution to the problem was found in the incorporation of 10% v/v water into the ethanolic drug layering solution, resulting in the production of drug-loaded pellets with a smooth morphology which allowed the application of a coherent outer coating able to retard drug release. The surprising difference in pellet morphology between the two solvent drug layering systems may be attributed to differences in solvent evaporation rates. This demonstrates that established techniques are sometimes less straightforward than thought as small changes in formulation have significant effects on the resulting product in a way which is not always well understood. PMID:19589378

  2. Observation of strong nano-effect via tuning distributed architecture of graphene oxide in poly(propylene carbonate)

    NASA Astrophysics Data System (ADS)

    Gao, Jian; Bai, Hongwei; Zhou, Xin; Yang, Guanghui; Xu, Chenlong; Zhang, Qin; Chen, Feng; Fu, Qiang

    2014-01-01

    For optimum reinforcement in polymer nanocomposite, a critical challenge is to realize the full ‘nano-effect’ of nanofillers at a high content, which is largely hindered by the strong tendency to aggregation of nanofillers. Here, by using a solvent-exchange and solution casting approach, we could incorporate a high-content graphene oxide (GO) into a soft biodegradable CO2-based poly(propylene carbonate) (PPC) up to 20 wt% with excellent dispersion. Based on this, the distributed architecture of GO could be tuned from a ‘GO dotted dispersion’ and ‘GO network’ to strong ‘GO co-continuous structure’ with increasing GO content. As a result, a very strong ‘nano-effect’ of GO in the PPC matrix was observed: (1) the glass transition temperature of PPC was improved from 25 to 45 ° C for slightly confined molecular chains, and even to 100 ° C for highly confined ones; (2) the modified PPC showed drastically enhanced high-temperature mechanical properties, comparable to those of traditional polymers such as polypropylene (PP) and biopolymer poly(lactic acid) (PLA); and (3) such modified PPC exhibited an exciting solvent resistance compared to neat PPC. Our work provides an example to improve the high-temperature properties of a polymer via formation of filler co-continuous structure.

  3. Ultra-Fast Flash Observatory (uffo) for Observation of Early Photons from Gamma Ray Bursts

    NASA Astrophysics Data System (ADS)

    Park, I. H.; Ahmad, S.; Barrillon, P.; Brandt, S.; Budtz-Jorgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang, M.-H. A.; Jung, A.; Jeong, S.; Kim, J. E.; Kim, M. B.; Kim, S.-W.; Kim, Y. W.; Krasnov, A. S.; Lee1, J.; Lim, H.; Linder, E. V.; Liu, T.-C.; Lund, N.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.; Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Suh, J. E.; Svertilov, S.; Vedenkin, N.; Wang, M.-Z.; Yashin, I.

    2013-12-01

    One of the least documented and understood aspects of gamma-ray bursts (GRB) is the rise phase of the optical light curve. The Ultra-Fast Flash Observatory (UFFO) is an effort to address this question through extraordinary opportunities presented by a series of space missions including a small spacecraft observatory. The UFFO is equipped with a fast-response Slewing Mirror Telescope (SMT) which uses rapidly moving mirror or mirror arrays to redirect the optical beam rather than slewing the entire spacecraft to aim the optical instrument at the GRB position. The UFFO will probe the early optical rise of GRBs with a sub-second response, for the first time, opening a completely new frontier in GRB and transient studies, the only GRB system which can point and measure on these time scales. Its fast response measurements of the optical emission of dozens of GRB each year will provide unique probes of the burst mechanism, shock breakouts in core-collapse supernovae, tidal disruptions around black holes, test Lorentz violation, be the electromagnetic counterpart to neutrino and gravitational wave signatures of the violent universe, and verify the prospect of GRB as a new standard candle potentially opening up the z>10 universe. As a first step, we employ a motorized slewing stage in SMT which can point to the event within 1s after X-ray trigger, in the UFFO-pathfinder payload onboard the Lomonosov satellite to be launched in 2012. The pathfinder was a small and limited, yet remarkably powerful micro-observatory for rapid optical response to bright gamma-ray bursts, the first part of our GRB and rapid-response long-term program. We describe the early photon science, the space mission of UFFO-pathfinder, and our plan for the next step.

  4. Observation and interpretation of fast sub-visual light pulses from the night sky

    NASA Technical Reports Server (NTRS)

    Nemzek, R. J.; Winckler, J. R.

    1989-01-01

    Fast large-aperture photometers directed at the zenith on clear nights near Minneapolis have recorded many light pulses in the msec time range, but aside from man-made events these were almost entirely due to Rayleigh-scattered distant lightning, with a residual very low rate (less than 0.1/hr) of unidentified pulses. It is argued that 1-msec light pulses seen in several previous experiments may also be mostly Rayleigh-scattered lightning, rather than fluorescent light due to electron precipitation from lightning-induced whistlers as previously proposed.

  5. High speed Infrared imaging method for observation of the fast varying temperature phenomena

    NASA Astrophysics Data System (ADS)

    Moghadam, Reza; Alavi, Kambiz; Yuan, Baohong

    With new improvements in high-end commercial R&D camera technologies many challenges have been overcome for exploring the high-speed IR camera imaging. The core benefits of this technology is the ability to capture fast varying phenomena without image blur, acquire enough data to properly characterize dynamic energy, and increase the dynamic range without compromising the number of frames per second. This study presents a noninvasive method for determining the intensity field of a High Intensity Focused Ultrasound Device (HIFU) beam using Infrared imaging. High speed Infrared camera was placed above the tissue-mimicking material that was heated by HIFU with no other sensors present in the HIFU axial beam. A MATLAB simulation code used to perform a finite-element solution to the pressure wave propagation and heat equations within the phantom and temperature rise to the phantom was computed. Three different power levels of HIFU transducers were tested and the predicted temperature increase values were within about 25% of IR measurements. The fundamental theory and methods developed in this research can be used to detect fast varying temperature phenomena in combination with the infrared filters.

  6. Obscura telescope with a MEMS micromirror array for space observation of transient luminous phenomena or fast-moving objects.

    PubMed

    Park, J H; Garipov, G K; Jeon, J A; Khrenov, B A; Kim, J E; Kim, M; Kim, Y K; Lee, C-H; Lee, J; Na, G W; Nam, S; Park, I H; Park, Y-S

    2008-12-01

    We introduce a novel telescope consisting of a pinhole-like camera with rotatable MEMS micromirrors substituting for pinholes. The design is ideal for observations of transient luminous phenomena or fast-moving objects, such as upper atmospheric lightning and bright gamma ray bursts. The advantage of the MEMS "obscura telescope" over conventional cameras is that it is capable both of searching for events over a wide field of view, and fast zooming to allow detailed investigation of the structure of events. It is also able to track the triggering object to investigate its space-time development, and to center the interesting portion of the image on the photodetector array. We present the proposed system and the test results for the MEMS obscura telescope which has a field of view of 11.3 degrees, sixteen times zoom-in and tracking within 1 ms. PMID:19065163

  7. Direct observation of ultrafast surface transport of laser-driven fast electrons in a solid target

    SciTech Connect

    Singh, Prashant Kumar; Chatterjee, Gourab; Adak, Amitava; Ahmed, Saima; Lad, Amit D.; Ravindra Kumar, G.; Cui, Y. Q.; Wang, W. M.; Sheng, Z. M.

    2013-11-15

    We demonstrate rapid spread of surface ionization on a glass target excited by an intense, ultrashort laser pulse at an intensity of 3 × 10{sup 17} W cm{sup −2}. Time- and space-resolved reflectivity of the target surface indicates that the initial plasma region created by the pump pulse expands at c/7. The measured quasi-static megagauss magnetic field is found to expand in a manner very similar to that of surface ionization. Two-dimensional particle-in-cell simulations reproduce measurements of surface ionization and magnetic fields. Both the experiment and simulation convincingly demonstrate the role of self-induced electric and magnetic fields in confining fast electrons along the target-vacuum interface.

  8. Observation of fast expansion velocity with insulating tungsten wires on ˜80 kA facility

    NASA Astrophysics Data System (ADS)

    Li, M.; Zhang, J. H.; Wu, J.; Li, Y.; Sun, T. P.; Wang, L. P.; Sheng, L.; Qiu, M. T.; Mao, W. T.; Li, X. W.

    2016-07-01

    This paper presents experimental results on the effects of insulating coatings on tungsten planar wire array Z-pinches on an 80 kA, 100 ns current facility. Expansion velocity is obviously increased from ˜0.25 km/s to ˜3.5 km/s by using the insulating coatings. It can be inferred that the wire cores are in gaseous state with this fast expansion velocity. An optical framing camera and laser probing images show that the standard wire arrays have typical ablation process which is similar to their behaviors on mega-ampere facilities. The ablation process and precursor plasma are suppressed for dielectric tungsten wires. The wire array implosion might be improved if these phenomena can be reproduced on Mega-ampere facilities.

  9. Direct observation of ultrafast surface transport of laser-driven fast electrons in a solid target

    NASA Astrophysics Data System (ADS)

    Singh, Prashant Kumar; Cui, Y. Q.; Chatterjee, Gourab; Adak, Amitava; Wang, W. M.; Ahmed, Saima; Lad, Amit D.; Sheng, Z. M.; Ravindra Kumar, G.

    2013-11-01

    We demonstrate rapid spread of surface ionization on a glass target excited by an intense, ultrashort laser pulse at an intensity of 3 × 1017 W cm-2. Time- and space-resolved reflectivity of the target surface indicates that the initial plasma region created by the pump pulse expands at c/7. The measured quasi-static megagauss magnetic field is found to expand in a manner very similar to that of surface ionization. Two-dimensional particle-in-cell simulations reproduce measurements of surface ionization and magnetic fields. Both the experiment and simulation convincingly demonstrate the role of self-induced electric and magnetic fields in confining fast electrons along the target-vacuum interface.

  10. Observation of a fast beta collapse during high poloidal-beta discharges in JT-60

    SciTech Connect

    Ishida, S.; Koide, Y.; Ozeki, T.; Kikuchi, M.; Tsuji, S.; Shirai, H.; Naito, O.; Azumi, M. )

    1992-03-09

    A nondisruptive {beta}-limiting phenomenon in a large tokamak under a large bootstrap current fraction, up to {similar to}80% of the plasma current, is described; {beta}=(plasma pressure)/(magnetic pressure). During long-pulse neutral-beam-heated discharges in the JT-60 tokamak, it occurs at {beta}{sub {ital p}}{similar to}3, leading to a limit of the normalized {beta} lower than the Troyon limit. The MHD feature is characterized by a large-amplitude partial relaxation with a fast growth time. A hollow current profile evolution in the high-{beta}{sub {ital p}} regime plays an essential role in the MHD stability, analysis of which shows that the ideal {ital n}=1 kink-ballooning modes can be unstable just before the collapse.

  11. OBSERVATIONAL TEST OF STOCHASTIC HEATING IN LOW-{beta} FAST-SOLAR-WIND STREAMS

    SciTech Connect

    Bourouaine, Sofiane; Chandran, Benjamin D. G.

    2013-09-10

    Spacecraft measurements show that protons undergo substantial perpendicular heating during their transit from the Sun to the outer heliosphere. In this paper, we use Helios 2 measurements to investigate whether stochastic heating by low-frequency turbulence is capable of explaining this perpendicular heating. We analyze Helios 2 magnetic field measurements in low-{beta} fast-solar-wind streams between heliocentric distances r = 0.29 AU and r = 0.64 AU to determine the rms amplitude of the fluctuating magnetic field, {delta}B{sub p}, near the proton gyroradius scale {rho}{sub p}. We then evaluate the stochastic heating rate Q{sub stoch} using the measured value of {delta}B{sub p} and a previously published analytical formula for Q{sub stoch}. Using Helios measurements we estimate the ''empirical'' perpendicular heating rate Q{sub Up-Tack emp} = (k{sub B}/m{sub p}) BV (d/dr) (T{sub Up-Tack p}/B) that is needed to explain the T{sub p} profile. We find that Q{sub stoch} {approx} Q{sub emp}, but only if a key dimensionless constant appearing in the formula for Q{sub stoch} lies within a certain range of values. This range is approximately the same throughout the radial interval that we analyze and is consistent with the results of numerical simulations of the stochastic heating of test particles in reduced magnetohydrodynamic turbulence. These results support the hypothesis that stochastic heating accounts for much of the perpendicular proton heating occurring in low-{beta} fast-wind streams.

  12. Magnetic rotor flux observer of induction motors with fast convergence and less transient oscillation

    NASA Astrophysics Data System (ADS)

    Park, Chang-Woo; Hwang, Jung-Hoon

    2013-03-01

    This paper presents an observer design for the estimation of magnetic rotor flux of induction motors. We characterize the class of MIMO induction motor systems that consists of the linear observable and the nonlinear part with a block triangular structure. The similarity transformation that plays an important role in proving the convergence of the proposed observer is generalized to the systems. Since the gain of the proposed observer minimizes a nonlinear part of the system to suppress for the stability of the error dynamics, it improves the transient performance of the high gain observer. Moreover, by using the generalized similarity transformation, it is shown that under some observability and boundedness conditions, the proposed observer guarantees the global exponential convergence to zero of the estimation error. Since the proposed scheme minimizes the nonlinearity of an induction motor system, it improves the transient performance of the observer and guarantees the global exponential convergence to zero of the estimation error. The estimation results of magnetic rotor fluxes through experiments are shown and it is presented that the proposed magnetic flux observer exhibits less transient oscillation and faster convergence time than the general observer.

  13. Cosmic ray modulation at the solar maximum: Ulysses observations during the fast latitude scan of the inner heliosphere*

    NASA Astrophysics Data System (ADS)

    Zhang, M.; McKibben, R. B.; Lopate, C.

    2002-05-01

    Starting at the maximum southern latitude of 80o in November 2000, Ulysses made a fast latitude scan of the inner heliosphere within approximately one year at the time of maximum solar activity. It passed through a perihelion at 1.34 AU near the solar equator in May 2001, and reached its maximum northern latitude in October 2001. The fast latitude scan provides best conditions for the determination of cosmic ray latitudinal gradients because of little expected drift of instrument performance and a small coverage of radial distance (2.2 to 1.34 AU). Although the time period is dominated by solar energetic particle events, measurements from the High-Energy Telescope on the Ulysses COSPIN experiment together with simultaneous measurements from the University of Chicago Charge Particle Telescope on IMP-8 near Earth made during rare solar quiet time periods found that the latitudinal gradient of cosmic ray intensities is essentially zero for all nuclei of energies above 30 MeV/n. Compared to the measurements of small cosmic ray latitude gradients made by Ulysses' first fast latitude scan at the 1994-1995 solar minimum, this observation indicates that the inner heliosphere is more spherically symmetric at the solar maximum. In this paper, we will discuss its implications to the understanding of the structure of heliospheric magnetic fields and the mechanisms of particle transport. * This work was supported in part by NASA Contract JPL-955432 and by NASA Grants NAG5-11036 and NAG5-10888

  14. A Repeating Fast Radio Burst: Radio and X-ray Follow-up Observations of FRB 121102

    NASA Astrophysics Data System (ADS)

    Scholz, Paul; Spitler, Laura; Hessels, Jason; Bogdanov, Slavko; Brazier, Adam; Camilo, Fernando; Chatterjee, Shami; Cordes, James M.; Crawford, Fronefield; Deneva, Julia S.; Ferdman, Robert; Freire, Paulo; Kaspi, Victoria M.; Lazarus, Patrick; Lynch, Ryan; Madsen, Erik; McLaughlin, Maura; Patel, Chitrang; Ransom, Scott M.; Seymour, Andrew; Stairs, Ingrid H.; Stappers, Benjamin; van Leeuwen, Joeri; Zhu, Weiwei

    2016-04-01

    A new phenomenon has emerged in high-energy astronomy in the past few years: the Fast Radio Burst. Fast Radio Bursts (FRBs) are millisecond-duration radio bursts whose dispersion measures imply that they originate from far outside of the Galaxy. Their origin is as yet unknown; their durations and energetics imply that they involve compact objects, such as neutron stars or black holes. Due to their extreme luminosities implied by their distances and the previous absence of any repeat burst in follow-up observations, many potential explanations involve one-time cataclysmic events. However, in our Arecibo telescope follow-up observations of FRB 121102 (discovered in the PALFA survey; Spitler et al. 2014), we find additional bursts at the same location and dispersion measure as the original burst. We also present the results of Swift and Chandra X-ray observations of the field. This result shows that, for at least a sub-set of the FRB population, the source can repeat and thus cannot be explained by a cataclysmic origin.

  15. Covariance approximation for fast and accurate computation of channelized Hotelling observer statistics

    SciTech Connect

    Bonetto, Paola; Qi, Jinyi; Leahy, Richard M.

    1999-10-01

    We describe a method for computing linear observer statistics for maximum a posteriori (MAP) reconstructions of PET images. The method is based on a theoretical approximation for the mean and covariance of MAP reconstructions. In particular, we derive here a closed form for the channelized Hotelling observer (CHO) statistic applied to 2D MAP images. We show reasonably good correspondence between these theoretical results and Monte Carlo studies. The accuracy and low computational cost of the approximation allow us to analyze the observer performance over a wide range of operating conditions and parameter settings for the MAP reconstruction algorithm.

  16. Model Analysis of Fast Photochemistry Over the Arctic Using In-Situ ARCTAS and TOPSE observations

    NASA Astrophysics Data System (ADS)

    Olson, J. R.; Crawford, J. H.; Chen, G.; Brune, W. H.; Ren, X.; Mao, J.; Fried, A.; Weibring, P.; Walega, J.; Weinheimer, A. J.; Knapp, D. J.; Wennberg, P. O.; Crounse, J.; St Clair, J.

    2011-12-01

    Aircraft observations of constituents and meteorological quantities observed during the two seasonal Arctic phases of ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) and during the 2000 TOPSE (Tropospheric Ozone Production About the Spring Equinox) are analyzed using an observationally-constrained steady state box model. An examination of the springtime Arctic portion of the 2000 TOPSE program shows a highly similar meteorological background and chemical composition relative to ARCTAS-A, with the exception of peroxides. Concentrations of H2O2 observed during ARCTAS-A were 2-3 times larger than those during TOPSE. The cause of this discrepancy is unresolved, and it will be shown to have important implications for conclusions related to the Arctic HOx budget. Measurements of HOx from the Penn State ATHOS instrument are available during ARCTAS and are compared to box model predictions. Model predictions show striking inconsistencies during both phases of ARCTAS between observed concentrations of HO2 and of HOx precursors, primarily H2O2 and CH2O. Using observations of precursors in the box model results in predictions of HO2 that are up to nearly a factor of 2 larger than observed. An estimated temperature-dependent terminal loss rate of HO2 to aerosol [Mao et al., 2010] was shown to be insufficient to reconcile model predictions and observations of HO2. When the terminal losses from GEOS-Chem are directly inserted into the fully constrained boxmodel, predictions of upper tropospheric HO2 decrease by no more than 15-25%. Steady state predictions of upper tropospheric CH2O are lower than observations by factors of 2-4 during both phases of ARCTAS. Likewise, steady state predictions of H2O2 are lower than observations by factors of 2-3, and are similar to concentrations measured during TOPSE. Global models suggest that there is an important transport component to the Arctic H2O2 budget not captured by steady state models. An

  17. GPS Observation of Fast-moving Continent-size Traveling TEC Pulsations at the Start of Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Pradipta, R.; Valladares, C. E.; Doherty, P. H.

    2014-12-01

    Using network of GPS receiver stations in North and South America, we have recently observed fast-moving continent-size traveling plasma disturbances in the mapped total electron content (TEC) data. These space plasma disturbances occurred at the beginning of geomagnetic storms, immediately after the storm's suddent commencement (SSC) and prior to the appearance of large-scale traveling ionospheric disturbances (LSTIDs) from the auroral regions. More specifically, these supersize TEC perturbations were observed when the IMF Bz was oscillating between northward and southward directions. They were found to propagate zonally westward with a propagation speed of 2-3 km/s, if projected onto an ionospheric-equivalent altitude of 350 km. Based on their general characteristics and comparison with ground-based ionosonde data, we interpret these TEC pulsations as ion drift waves in the magnetosphere/plasmasphere that propagate azimuthally inside the GPS orbit.

  18. Online Fault Detection of Permanent Magnet Demagnetization for IPMSMs by Nonsingular Fast Terminal-Sliding-Mode Observer

    PubMed Central

    Zhao, Kai-Hui; Chen, Te-Fang; Zhang, Chang-Fan; He, Jing; Huang, Gang

    2014-01-01

    To prevent irreversible demagnetization of a permanent magnet (PM) for interior permanent magnet synchronous motors (IPMSMs) by flux-weakening control, a robust PM flux-linkage nonsingular fast terminal-sliding-mode observer (NFTSMO) is proposed to detect demagnetization faults. First, the IPMSM mathematical model of demagnetization is presented. Second, the construction of the NFTSMO to estimate PM demagnetization faults in IPMSM is described, and a proof of observer stability is given. The fault decision criteria and fault-processing method are also presented. Finally, the proposed scheme was simulated using MATLAB/Simulink and implemented on the RT-LAB platform. A number of robustness tests have been carried out. The scheme shows good performance in spite of speed fluctuations, torque ripples and the uncertainties of stator resistance. PMID:25490582

  19. Clinical observations of early and late normal tissue injury in patients receiving fast neutron irradiation

    SciTech Connect

    Ornitz, R.D.; Bradley, E.W.; Mossman, K.L.; Fender, F.M.; Schell, M.C.; Rogers, C.C.

    1980-03-01

    This communication describes early and late normal tissue effects in 177 patients treated totally or in part by 15 MeV neutrons from the Naval Research Laboratory Cyclotron in Washington, D.C. between October 1973 and December 1976. Late normal tissue reactions were found to be greater than would be expected from careful observation of the early clinical responses to neutron treatment. Neutron prescriptions must be written based on the late effect tolerance level experience which is being accumulated at several neutron therapy facilities.

  20. Can model observers be developed to reproduce radiologists' diagnostic performances? Our study says not so fast!

    NASA Astrophysics Data System (ADS)

    Lee, Juhun; Nishikawa, Robert M.; Reiser, Ingrid; Boone, John M.

    2016-03-01

    The purpose of this study was to determine radiologists' diagnostic performances on different image reconstruction algorithms that could be used to optimize image-based model observers. We included a total of 102 pathology proven breast computed tomography (CT) cases (62 malignant). An iterative image reconstruction (IIR) algorithm was used to obtain 24 reconstructions with different image appearance for each image. Using quantitative image feature analysis, three IIRs and one clinical reconstruction of 50 lesions (25 malignant) were selected for a reader study. The reconstructions spanned a range of smooth-low noise to sharp-high noise image appearance. The trained classifiers' AUCs on the above reconstructions ranged from 0.61 (for smooth reconstruction) to 0.95 (for sharp reconstruction). Six experienced MQSA radiologists read 200 cases (50 lesions times 4 reconstructions) and provided the likelihood of malignancy of each lesion. Radiologists' diagnostic performances (AUC) ranged from 0.7 to 0.89. However, there was no agreement among the six radiologists on which image appearance was the best, in terms of radiologists' having the highest diagnostic performances. Specifically, two radiologists indicated sharper image appearance was diagnostically superior, another two radiologists indicated smoother image appearance was diagnostically superior, and another two radiologists indicated all image appearances were diagnostically similar to each other. Due to the poor agreement among radiologists on the diagnostic ranking of images, it may not be possible to develop a model observer for this particular imaging task.

  1. Rapid Sediment Erosion and Drumlin Formation Observed Beneath a Fast-Flowing Antarctic Ice Stream

    NASA Astrophysics Data System (ADS)

    Smith, A. M.; Murray, T.; Nicholls, K. W.; Makinson, K.; Adalgeirsdottir, G.; Behar, A. E.

    2005-12-01

    What happens beneath a glacier affects both the way it flows and the landforms left behind when it retreats. Unfortunately, although the subglacial environment is one of the most critical to understanding ice flow and the processes of bedform formation, it is also the most difficult to study. As part of the RABID project on Rutford Ice Stream, West Antarctica in 2004/05, seismic reflection data were acquired at the same geographic location as identical surveys conducted 7 and 13 years previously. Analysis of the data from all 3 seismic surveys gives both the bed topography and an indication of the bed material and basal conditions. In particular, we can distinguish between places where the bed is soft, water-saturated sediments, probably deforming pervasively with the motion of the overlying ice, and those where the bed, whilst still sedimentary, is harder and the ice flow is probably dominated by basal sliding. Over the six years between the first and second surveys, 6 m of sediment was eroded from a region of the bed approximately 500 m wide. This occurs in one of the basal sliding areas. Typical interpreted and modelled subglacial erosion rates from all glacial environments are normally of the order of 0.1-100 mm/a. Our minimum observed rate of 1 m/a is remarkably high, particularly for a glacier which appears to have been in overall steady-state for at least many hundreds of years, and probably much longer. Over the seven years between the second and third surveys, further major changes occurred at the ice stream bed. The previous erosion ceased. Subsequently, a large mound of deforming sediment over-rode this same area of the glacier bed. This mound is 10 m high, 100 m wide and at least a few hundred metres long. This is a very short time for the formation of such a large feature, only 7 years previously nothing of its kind existed at this location. We interpret these dimensions and sediment characteristics as an actively-forming drumlin. Our results are the

  2. Design of fast state observers using a backstepping-like approach with application to synchronization of chaotic systems

    NASA Astrophysics Data System (ADS)

    Zaher, Ashraf A.

    2008-06-01

    A simple technique is introduced to build fast state observers for chaotic systems when only a scalar time series of the output is available. This technique relies on using a backstepping-like approach via introducing new virtual states that can be observed using the drive-response synchronization mechanism. The proposed dynamic structure of the virtual states allows for employing control parameters that can adjust the convergence rate of the observed states. In addition, these control parameters can be used to improve the transient performance of the response system to accommodate small and large variations of the initial conditions, thus achieving superior performance to conventional synchronization techniques. Simple Lyapunov functions are used to estimate the range of the control parameters that guarantees stable operation of the proposed technique. Three benchmark chaotic systems are considered for illustration; namely, the Lorenz, Chua, and Rössler systems. The conflict between stability and agility of the states observer is analyzed and a simple tuning mechanism is introduced. Implementation of the proposed technique in both analog and digital forms is also addressed and experimental results are reported ensuring feasibility and real-time applicability. Finally, advantages and limitations are discussed and a comparison with conventional synchronization methods is investigated.

  3. Design of fast state observers using a backstepping-like approach with application to synchronization of chaotic systems.

    PubMed

    Zaher, Ashraf A

    2008-06-01

    A simple technique is introduced to build fast state observers for chaotic systems when only a scalar time series of the output is available. This technique relies on using a backstepping-like approach via introducing new virtual states that can be observed using the drive-response synchronization mechanism. The proposed dynamic structure of the virtual states allows for employing control parameters that can adjust the convergence rate of the observed states. In addition, these control parameters can be used to improve the transient performance of the response system to accommodate small and large variations of the initial conditions, thus achieving superior performance to conventional synchronization techniques. Simple Lyapunov functions are used to estimate the range of the control parameters that guarantees stable operation of the proposed technique. Three benchmark chaotic systems are considered for illustration; namely, the Lorenz, Chua, and Rossler systems. The conflict between stability and agility of the states observer is analyzed and a simple tuning mechanism is introduced. Implementation of the proposed technique in both analog and digital forms is also addressed and experimental results are reported ensuring feasibility and real-time applicability. Finally, advantages and limitations are discussed and a comparison with conventional synchronization methods is investigated. PMID:18601481

  4. Energy calibration issues in nuclear resonant vibrational spectroscopy: observing small spectral shifts and making fast calibrations.

    PubMed

    Wang, Hongxin; Yoda, Yoshitaka; Dong, Weibing; Huang, Songping D

    2013-09-01

    The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-(57)Fe-enriched [Fe4S4Cl4](=) and 10%-(57)Fe and 90%-(54)Fe labeled [Fe4S4Cl4](=) has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3-4 h to about 30 min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements. PMID:23955030

  5. NuSTAR AND SWIFT Observations of the Fast Rotating Magnetized White Dwarf AE Aquarii

    NASA Technical Reports Server (NTRS)

    Kitaguchi, Takao; An, Hongjun; Beloborodov, Andrei M.; Gotthelf, Eric V.; Hayashi, Takayuki; Kaspi, Victoria M.; Rana, Vikram R.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Hailey, Charles J.; Harrison, Fiona A.; Stern, Daniel; Zhang, Will W.

    2014-01-01

    AE Aquarii is a cataclysmic variable with the fastest known rotating magnetized white dwarf (P(sub spin) = 33.08 s). Compared to many intermediate polars, AE Aquarii shows a soft X-ray spectrum with a very low luminosity (LX (is) approximately 10(exp 31) erg per second). We have analyzed overlapping observations of this system with the NuSTAR and the Swift X-ray observatories in 2012 September. We find the 0.5-30 keV spectra to be well fitted by either an optically thin thermal plasma model with three temperatures of 0.75(+0.18 / -0.45), 2.29(+0.96 / -0.82), and 9.33 (+6.07 / -2.18) keV, or an optically thin thermal plasma model with two temperatures of 1.00 (+0.34 / -0.23) and 4.64 (+1.58 / -0.84) keV plus a power-law component with photon index of 2.50 (+0.17 / -0.23). The pulse profile in the 3-20 keV band is broad and approximately sinusoidal, with a pulsed fraction of 16.6% +/- 2.3%. We do not find any evidence for a previously reported sharp feature in the pulse profile.

  6. NuStar and Swift Observations of the Fast Rotating Magnetized White Dwarf AE Aquarii

    NASA Technical Reports Server (NTRS)

    Kitaguchi, Takao; An, Hongjun; Beloborodov, Andrei M.; Gotthelf, Eric V.; Hayashi, Takayuki; Kaspi, Victoria M.; Rana, Vikram R.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Hailey, Charles J.; Harrison, Fiona A.; Stern, Daniel; Zhang, Will W.

    2014-01-01

    AE Aquarii is a cataclysmic variable with the fastest known rotating magnetized white dwarf (P(sub spin) = 33.08 s). Compared to many intermediate polars, AE Aquarii shows a soft X-ray spectrum with a very low luminosity (LX (is) approximately 10(exp 31) erg per second). We have analyzed overlapping observations of this system with the NuSTAR and the Swift X-ray observatories in 2012 September. We find the 0.5-30 keV spectra to be well fitted by either an optically thin thermal plasma model with three temperatures of 0.75(+0.18 / -0.45), 2.29(+0.96 / -0.82), and 9.33 (+6.07 / -2.18) keV, or an optically thin thermal plasma model with two temperatures of 1.00 (+0.34 / -0.23) and 4.64 (+1.58 / -0.84) keV plus a power-law component with photon index of 2.50 (+0.17 / -0.23). The pulse profile in the 3-20 keV band is broad and approximately sinusoidal, with a pulsed fraction of 16.6% +/- 2.3%. We do not find any evidence for a previously reported sharp feature in the pulse profile.

  7. FAST TRACK PAPER: Regional observations of the second North Korean nuclear test on 2009 May 25

    NASA Astrophysics Data System (ADS)

    Shin, Jin Soo; Sheen, Dong-Hoon; Kim, Geunyoung

    2010-01-01

    The suspicious seismic event that occurred in the northern Korean Peninsula on 2009 May 25 was declared to be the second underground nuclear test (NK2ND) by North Korea. We investigated the characteristics of NK2ND using seismic signals recorded at regional-distance stations in South Korea and China. The Pn/Lg ratios of NK2ND definitely discriminate this event from two nearby natural earthquakes at frequencies above 4 Hz. Full moment tensor inversion of full waveform data shows that NK2ND had a very large isotropic component. Pure isotropic moment tensor inversion also resulted in good recovery of observed waveforms, with clear indication that NK2ND was explosive in origin. The moment magnitude (Mw) from the full moment tensor inversion was estimated to be 4.5 and network-averaged values of 4.6 and 3.6 were calculated for rms mb(Lg) and Ms(VMAX), respectively. Although mb - Ms signature has been considered one of the most reliable discriminants for separating explosions and earthquakes, this signature showed poor discrimination in the case of NK2ND. The Pn/Lg ratios and moment tensor inversion give more reliable evidence than does the mb - Ms for classifying the suspicious event in the northern Korean Peninsula as a possible explosion. The characteristics of NK2ND are also quite similar to those of the first North Korean nuclear test on 2006 October 9.

  8. Combined Multipoint Remote and In Situ Observations of the Asymmetric Evolution of a Fast Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Rollett, Tanja; Möstl, Christian; Temmer, Manuela; Frahm, Rudy A.; Davies, Jackie A.; Veronig, Astrid M.; Vrsnak, Bojan; Amerstorfer, Ute V.; Farrugia, Charles J.; Zic, Tomislav; Zhang, Tielong

    2015-04-01

    A significant number of in situ detections and remote observations have allowed us to strongly constrain the shape of the fast coronal mass ejection (CME) of 7 March 2012 during its evolution through interplanetary space. The CME was imaged by both STEREO spacecraft and detected in situ by MESSENGER, Venus Express, Wind and Mars Express. Applying the novel constrained self-similar expansion method, which combines observations from STEREO's heliospheric imaging facilities with the four in situ detections, we derived different kinematical profiles for two different segments of the same CME. For the Venus- (and Mercury-) directed segment we found a gradual deceleration while the Earth- (and Mars-) directed part was decelerated abruptly close to the Sun. In order to study the background solar wind conditions we used a drag-based model, which revealed a comparatively small drag-force acting on the Venus-directed CME segment possibly caused by a preceding CME that cleared the way for the CME under study. The Earth-directed segment may have also been affected by a preceding CME. Here, we found different solar wind conditions along the CME path. A high drag-parameter below 35 solar radii suggests a high drag-force acting against the CME propagation, causing a strong deceleration. Subsequently, this part of the CME propagated with an almost constant speed. The resulting deformation of the overall CME shape underlines the importance of using stereoscopic observations for being able to reduce the arrival time error in space weather forecasting.

  9. Construction of a High Temporal-spectral Resolution Spectrometer for Detection of Fast Transients from Observations of the Sun at 1.4 GHz.

    NASA Astrophysics Data System (ADS)

    Casillas-Perez, G. A.; Jeyakumar, S.; Perez-Enriquez, R.

    2014-12-01

    Transients explosive events with time durations from nanoseconds to several hours, are observed in the Sun at high energy bands such as gamma ray and xray. In the radio band, several types of radio bursts are commonly detected from the ground. A few observations of the Sun in the past have also detected a new class of fast transients which are known to have short-live electromagnetic emissions with durations less than 100 ms. The mechanisms that produce such fast transiets remain unclear. Observations of such fast transients over a wide bandwidth is necessary to uderstand the underlying physical process that produce such fast transients. Due to their very large flux densities, fast radio transients can be observed at high time resolution using small antennas in combination with digital signal processing techniques. In this work we report the progress of an spectrometer that is currently in construction at the Observatorio de la Luz of the Universidad de Guanajuato. The instrument which will have the purpose of detecting solar fast radio transients, involves the use of digital devices such as FPGA and ADC cards, in addition with a receiver with high temporal-spectral resolution centered at 1.4 GHz and a pair of 2.3 m satellite dish.

  10. Structural changes of block copolymers with bi-modal orientation under fast cyclical stretching as observed by synchrotron SAXS

    PubMed Central

    Brubert, J.; Serrani, M.; Talhat, A.; De Gaetano, F.; Costantino, M. L.; Moggridge, G. D.

    2015-01-01

    Load-bearing tissues are composite materials that depend strongly on anisotropic fibre arrangement to maximise performance. One such tissue is the heart valve, with orthogonally arranged fibrosa and ventricularis layers. Their function is to maintain mechanical stress while being resilient. It is postulated that while one layer bears the applied stress, the orthogonal layer helps to regenerate the microstructure when the load is released. The present paper describes changes in the microstructure of a block copolymer with cylindrical morphology, having a bio-inspired microstructure of anisotropic orthogonally oriented layers, under uniaxial strain. To allow structural observations during fast deformation, equivalent to the real heart valve operation, we used a synchrotron X-ray source and recorded 2D SAXS patterns in only 1 ms per frame. The deformation behaviour of the composite microstructure has been reported for two arrangements of the cylinders in skin and core layers. The behaviour is very different to that observed either for uniaxially oriented or isotropic samples. Deformation is far from being affine. Cylinders aligned in the direction of stretch show fragmentation, but complete recovery of the spacing between cylinders on removal of the load. Those oriented perpendicular to the direction of stretch incline at an angle of approximately 25° to their original direction during load. PMID:25781560

  11. Super-resolution imaging with Pontamine Fast Scarlet 4BS enables direct visualization of cellulose orientation and cell connection architecture in onion epidermis cells

    PubMed Central

    2013-01-01

    Background In plants, a complex cell wall protects cells and defines their shape. Cellulose fibrils form a multilayered network inside the cell-wall matrix that plays a direct role in controlling cell expansion. Resolving the structure of this network will allow us to comprehend the relationship of cellulose fibril orientation and growth. The fluorescent dye Pontamine Fast Scarlet 4BS (PFS) was shown to stain cellulose with high specificity and could be used to visualize cellulose bundles in cell walls of Arabidopsis root epidermal cells with confocal microscopy. The resolution limit of confocal microscopy of some 200 nm in xy and 550 nm in z for green light, restricts the direct visualization of cellulose to relatively large bundles, whereas the structure of cellulose microfibrils with their diameter below 10 nm remains unresolved. Over the last decade, several so-called super-resolution microscopy approaches have been developed; in this paper we explore the potential of such approaches for the direct visualization of cellulose. Results To ensure optimal imaging we determined the spectral properties of PFS-stained tissue. PFS was found not to affect cell viability in the onion bulb scale epidermis. We present the first super-resolution images of cellulose bundles in the plant cell wall produced by direct stochastic optical reconstruction microscopy (dSTORM) in combination with total internal reflection fluorescence (TIRF) microscopy. Since TIRF limits observation to the cell surface, we tested as alternatives 3D-structured illumination microscopy (3D-SIM) and confocal microscopy, combined with image deconvolution. Both methods offer lower resolution than STORM, but enable 3D imaging. While 3D-SIM produced strong artifacts, deconvolution gave good results. The resolution was improved over conventional confocal microscopy and the approach could be used to demonstrate differences in fibril orientation in different layers of the cell wall as well as particular

  12. Fast and slow ion diffusion processes in lithium ion pouch cells during cycling observed with fiber optic strain sensors

    NASA Astrophysics Data System (ADS)

    Sommer, Lars Wilko; Kiesel, Peter; Ganguli, Anurag; Lochbaum, Alexander; Saha, Bhaskar; Schwartz, Julian; Bae, Chang-Jun; Alamgir, Mohamed; Raghavan, Ajay

    2015-11-01

    Cell monitoring for safe capacity utilization while maximizing pack life and performance is a key requirement for effective battery management and encouraging their adoption for clean-energy technologies. A key cell failure mode is the build-up of residual electrode strain over time, which affects both cell performance and life. Our team has been exploring the use of fiber optic (FO) sensors as a new alternative for cell state monitoring. In this present study, various charge-cycling experiments were performed on Lithium-ion pouch cells with a particular class of FO sensors, fiber Bragg gratings (FBGs), that were externally attached to the cells. An overshooting of the volume change at high SOC that recovers during rest can be observed. This phenomenon originates from the interplay between a fast and a slow Li ion diffusion process, which leads to non-homogeneous intercalation of Li ions. This paper focuses on the strain relaxation processes that occur after switching from charge to no-load phases. The correlation of the excess volume and subsequent relaxation to SOC as well as temperature is discussed. The implications of being able to monitor this phenomenon to control battery utilization for long life are also discussed.

  13. Combined Multipoint Remote and in situ Observations of the Asymmetric Evolution of a Fast Solar Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Rollett, T.; Möstl, C.; Temmer, M.; Frahm, R. A.; Davies, J. A.; Veronig, A. M.; Vršnak, B.; Amerstorfer, U. V.; Farrugia, C. J.; Žic, T.; Zhang, T. L.

    2014-07-01

    We present an analysis of the fast coronal mass ejection (CME) of 2012 March 7, which was imaged by both STEREO spacecraft and observed in situ by MESSENGER, Venus Express, Wind, and Mars Express. Based on detected arrivals at four different positions in interplanetary space, it was possible to strongly constrain the kinematics and the shape of the ejection. Using the white-light heliospheric imagery from STEREO-A and B, we derived two different kinematical profiles for the CME by applying the novel constrained self-similar expansion method. In addition, we used a drag-based model to investigate the influence of the ambient solar wind on the CME's propagation. We found that two preceding CMEs heading in different directions disturbed the overall shape of the CME and influenced its propagation behavior. While the Venus-directed segment underwent a gradual deceleration (from ~2700 km s-1 at 15 R ⊙ to ~1500 km s-1 at 154 R ⊙), the Earth-directed part showed an abrupt retardation below 35 R ⊙ (from ~1700 to ~900 km s-1). After that, it was propagating with a quasi-constant speed in the wake of a preceding event. Our results highlight the importance of studies concerning the unequal evolution of CMEs. Forecasting can only be improved if conditions in the solar wind are properly taken into account and if attention is also paid to large events preceding the one being studied.

  14. DISCOVERY OF ULTRA-FAST OUTFLOWS IN A SAMPLE OF BROAD-LINE RADIO GALAXIES OBSERVED WITH SUZAKU

    SciTech Connect

    Tombesi, F.; Sambruna, R. M.; Mushotzky, R. F.; Braito, V.; Ballo, L.; Cappi, M.

    2010-08-10

    We present the results of a uniform and systematic search for blueshifted Fe K absorption lines in the X-ray spectra of five bright broad-line radio galaxies observed with Suzaku. We detect, for the first time in radio-loud active galactic nuclei (AGNs) at X-rays, several absorption lines at energies greater than 7 keV in three out of five sources, namely, 3C 111, 3C 120, and 3C 390.3. The lines are detected with high significance according to both the F-test and extensive Monte Carlo simulations. Their likely interpretation as blueshifted Fe XXV and Fe XXVI K-shell resonance lines implies an origin from highly ionized gas outflowing with mildly relativistic velocities, in the range v {approx_equal} 0.04-0.15c. A fit with specific photoionization models gives ionization parameters in the range log {xi} {approx_equal} 4-5.6 erg s{sup -1} cm and column densities of N {sub H} {approx_equal} 10{sup 22}-10{sup 23} cm{sup -2}. These characteristics are very similar to those of the ultra-fast outflows (UFOs) previously observed in radio-quiet AGNs. Their estimated location within {approx}0.01-0.3 pc of the central super-massive black hole suggests a likely origin related with accretion disk winds/outflows. Depending on the absorber covering fraction, the mass outflow rate of these UFOs can be comparable to the accretion rate and their kinetic power can correspond to a significant fraction of the bolometric luminosity and is comparable to their typical jet power. Therefore, these UFOs can play a significant role in the expected feedback from the AGN to the surrounding environment and can give us further clues on the relation between the accretion disk and the formation of winds/jets in both radio-quiet and radio-loud AGNs.

  15. Discovery of Ultra-fast Outflows in a Sample of Broad-line Radio Galaxies Observed with Suzaku

    NASA Astrophysics Data System (ADS)

    Tombesi, F.; Sambruna, R. M.; Reeves, J. N.; Braito, V.; Ballo, L.; Gofford, J.; Cappi, M.; Mushotzky, R. F.

    2010-08-01

    We present the results of a uniform and systematic search for blueshifted Fe K absorption lines in the X-ray spectra of five bright broad-line radio galaxies observed with Suzaku. We detect, for the first time in radio-loud active galactic nuclei (AGNs) at X-rays, several absorption lines at energies greater than 7 keV in three out of five sources, namely, 3C 111, 3C 120, and 3C 390.3. The lines are detected with high significance according to both the F-test and extensive Monte Carlo simulations. Their likely interpretation as blueshifted Fe XXV and Fe XXVI K-shell resonance lines implies an origin from highly ionized gas outflowing with mildly relativistic velocities, in the range v ~= 0.04-0.15c. A fit with specific photoionization models gives ionization parameters in the range log ξ ~= 4-5.6 erg s-1 cm and column densities of N H ~= 1022-1023 cm-2. These characteristics are very similar to those of the ultra-fast outflows (UFOs) previously observed in radio-quiet AGNs. Their estimated location within ~0.01-0.3 pc of the central super-massive black hole suggests a likely origin related with accretion disk winds/outflows. Depending on the absorber covering fraction, the mass outflow rate of these UFOs can be comparable to the accretion rate and their kinetic power can correspond to a significant fraction of the bolometric luminosity and is comparable to their typical jet power. Therefore, these UFOs can play a significant role in the expected feedback from the AGN to the surrounding environment and can give us further clues on the relation between the accretion disk and the formation of winds/jets in both radio-quiet and radio-loud AGNs.

  16. Direct observation of the core/double-shell architecture of intense dual-mode luminescent tetragonal bipyramidal nanophosphors.

    PubMed

    Kim, Su Yeon; Jeong, Jong Seok; Mkhoyan, K Andre; Jang, Ho Seong

    2016-05-21

    Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors-Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4-and the C/D-S structure has been proved by extensive scanning transmission electron microscopy (STEM) analysis. Colloidal LiYF4:Ce,Tb nanophosphors with a tetragonal bipyramidal shape are synthesized for the first time and they show intense DC green light via energy transfer from Ce(3+) to Tb(3+) under illumination with ultraviolet (UV) light. The LiYF4:Ce,Tb nanophosphors show 65 times higher photoluminescence intensity than LiYF4:Tb nanophosphors under illumination with UV light and the LiYF4:Ce,Tb is adapted into a luminescent shell of the tetragonal bipyramidal C/D-S nanophosphors. The formation of the DC shell on the core significantly enhances UC luminescence from the UC core under irradiation of near infrared light and concurrently generates DC luminescence from the core/shell nanophosphors under UV light. Coating with an inert inorganic shell further enhances the UC-DC dual-mode luminescence by suppressing the surface quenching effect. The C/D-S nanophosphors show 3.8% UC quantum efficiency (QE) at 239 W cm(-2) and 73.0 ± 0.1% DC QE. The designed C/D-S architecture in tetragonal bipyramidal nanophosphors is rigorously verified by an energy dispersive X-ray spectroscopy (EDX) analysis, with the assistance of line profile simulation, using an aberration-corrected scanning transmission electron microscope equipped with a high-efficiency EDX. The feasibility of these C/D-S nanophosphors for transparent display devices is also considered. PMID:26729043

  17. Sawtooth-induced Fast-ion Transport in the DIII-D Tokamak: Observations and Comparison to Theory

    NASA Astrophysics Data System (ADS)

    Muscatello, C. M.; Heidbrink, W. W.; Pace, D. C.; Zhu, Y. B.; Kolesnichenko, Ya. I.; Lutsenko, V. V.; Yakovenko, Yu. V.; van Zeeland, M. A.; Fisher, R. K.; Tobias, B. J.

    2010-11-01

    Tokamak sawteeth consist of a reorganization of the plasma magnetic field and various plasma parameters. The extent to which the fast-ion distribution function F(x,v) is influenced can depend on the ions' distribution of pitch and energy as well as the nature of the crash. Recent sawtooth experiments at DIII-D employed the newly extended fast-ion deuterium-alpha (FIDA) diagnostic, 2D FIDA imaging, and the newly commissioned fast-ion loss detector. Consistent with theoretical predictions, the FIDA diagnostic indicates that passing particles are more strongly affected by a sawtooth crash than the trapped population. Furthermore, FIDA imaging reports a depletion of up to 50% of the central fast-ion density. Extensive experimental data provide a rigorous test bed of theoretical models.

  18. Architecture & Environment

    ERIC Educational Resources Information Center

    Erickson, Mary; Delahunt, Michael

    2010-01-01

    Most art teachers would agree that architecture is an important form of visual art, but they do not always include it in their curriculums. In this article, the authors share core ideas from "Architecture and Environment," a teaching resource that they developed out of a long-term interest in teaching architecture and their fascination with the…

  19. COMBINED MULTIPOINT REMOTE AND IN SITU OBSERVATIONS OF THE ASYMMETRIC EVOLUTION OF A FAST SOLAR CORONAL MASS EJECTION

    SciTech Connect

    Rollett, T.; Möstl, C.; Temmer, M.; Veronig, A. M.; Amerstorfer, U. V.; Frahm, R. A.; Davies, J. A.; Vršnak, B.; Žic, T.; Farrugia, C. J.; Zhang, T. L.

    2014-07-20

    We present an analysis of the fast coronal mass ejection (CME) of 2012  March 7, which was imaged by both STEREO spacecraft and observed in situ by MESSENGER, Venus Express, Wind, and Mars Express. Based on detected arrivals at four different positions in interplanetary space, it was possible to strongly constrain the kinematics and the shape of the ejection. Using the white-light heliospheric imagery from STEREO-A and B, we derived two different kinematical profiles for the CME by applying the novel constrained self-similar expansion method. In addition, we used a drag-based model to investigate the influence of the ambient solar wind on the CME's propagation. We found that two preceding CMEs heading in different directions disturbed the overall shape of the CME and influenced its propagation behavior. While the Venus-directed segment underwent a gradual deceleration (from ∼2700 km s{sup –1} at 15 R {sub ☉} to ∼1500 km s{sup –1} at 154 R {sub ☉}), the Earth-directed part showed an abrupt retardation below 35 R {sub ☉} (from ∼1700 to ∼900 km s{sup –1}). After that, it was propagating with a quasi-constant speed in the wake of a preceding event. Our results highlight the importance of studies concerning the unequal evolution of CMEs. Forecasting can only be improved if conditions in the solar wind are properly taken into account and if attention is also paid to large events preceding the one being studied.

  20. Direct observation of the core/double-shell architecture of intense dual-mode luminescent tetragonal bipyramidal nanophosphors

    NASA Astrophysics Data System (ADS)

    Kim, Su Yeon; Jeong, Jong Seok; Mkhoyan, K. Andre; Jang, Ho Seong

    2016-05-01

    Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors--Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4--and the C/D-S structure has been proved by extensive scanning transmission electron microscopy (STEM) analysis. Colloidal LiYF4:Ce,Tb nanophosphors with a tetragonal bipyramidal shape are synthesized for the first time and they show intense DC green light via energy transfer from Ce3+ to Tb3+ under illumination with ultraviolet (UV) light. The LiYF4:Ce,Tb nanophosphors show 65 times higher photoluminescence intensity than LiYF4:Tb nanophosphors under illumination with UV light and the LiYF4:Ce,Tb is adapted into a luminescent shell of the tetragonal bipyramidal C/D-S nanophosphors. The formation of the DC shell on the core significantly enhances UC luminescence from the UC core under irradiation of near infrared light and concurrently generates DC luminescence from the core/shell nanophosphors under UV light. Coating with an inert inorganic shell further enhances the UC-DC dual-mode luminescence by suppressing the surface quenching effect. The C/D-S nanophosphors show 3.8% UC quantum efficiency (QE) at 239 W cm-2 and 73.0 +/- 0.1% DC QE. The designed C/D-S architecture in tetragonal bipyramidal nanophosphors is rigorously verified by an energy dispersive X-ray spectroscopy (EDX) analysis, with the assistance of line profile simulation, using an aberration-corrected scanning transmission electron microscope equipped with a high-efficiency EDX. The feasibility of these C/D-S nanophosphors for transparent display devices is also considered.Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors--Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4--and the C/D-S structure

  1. Project Integration Architecture: Application Architecture

    NASA Technical Reports Server (NTRS)

    Jones, William Henry

    2005-01-01

    The Project Integration Architecture (PIA) implements a flexible, object-oriented, wrapping architecture which encapsulates all of the information associated with engineering applications. The architecture allows the progress of a project to be tracked and documented in its entirety. Additionally, by bringing all of the information sources and sinks of a project into a single architectural space, the ability to transport information between those applications is enabled.

  2. Controlling Material Reactivity Using Architecture.

    PubMed

    Sullivan, Kyle T; Zhu, Cheng; Duoss, Eric B; Gash, Alexander E; Kolesky, David B; Kuntz, Joshua D; Lewis, Jennifer A; Spadaccini, Christopher M

    2016-03-01

    3D-printing methods are used to generate reactive material architectures. Several geometric parameters are observed to influence the resultant flame propagation velocity, indicating that the architecture can be utilized to control reactivity. Two different architectures, channels and hurdles, are generated, and thin films of thermite are deposited onto the surface. The architecture offers an additional route to control, at will, the energy release rate in reactive composite materials. PMID:26669517

  3. Optical and near-IR observations of the faint and fast 2008ha-like supernova 2010ae

    NASA Astrophysics Data System (ADS)

    Stritzinger, M. D.; Hsiao, E.; Valenti, S.; Taddia, F.; Rivera-Thorsen, T. J.; Leloudas, G.; Maeda, K.; Pastorello, A.; Phillips, M. M.; Pignata, G.; Baron, E.; Burns, C. R.; Contreras, C.; Folatelli, G.; Hamuy, M.; Höflich, P.; Morrell, N.; Prieto, J. L.; Benetti, S.; Campillay, A.; Haislip, J. B.; LaClutze, A. P.; Moore, J. P.; Reichart, D. E.

    2014-01-01

    A comprehensive set of optical and near-infrared (NIR) photometry and spectroscopy is presented for the faint and fast 2008ha-like supernova (SN) 2010ae. Contingent on the adopted value of host extinction, SN 2010ae reached a peak brightness of -13.8 > MV > -15.3 mag, while modeling of the UVOIR light curve suggests it produced 0.003-0.007 M⊙ of 56Ni, ejected 0.30-0.60 M⊙ of material, and had an explosion energy of 0.04-0.30 × 1051 erg. The values of these explosion parameters are similar to the peculiar SN 2008ha -for which we also present previously unpublished early phase optical and NIR light curves - and places these two transients at the faint end of the 2002cx-like SN population. Detailed inspection of the post-maximum NIR spectroscopic sequence indicates the presence of a multitude of spectral features, which are identified through SYNAPPS modeling to be mainly attributed to Co ii. Comparison with a collection of published and unpublished NIR spectra of other 2002cx-like SNe, reveals that a Co ii footprint is ubiquitous to this subclass of transients, providing a link to Type Ia SNe. A visual-wavelength spectrum of SN 2010ae obtained at +252 days past maximum shows a striking resemblance to a similar epoch spectrum of SN 2002cx. However, subtle differences in the strength and ratio of calcium emission features, as well as diversity among similar epoch spectra of other 2002cx-like SNe indicates a range of physical conditions of the ejecta, highlighting the heterogeneous nature of thispeculiar class of transients. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile (ESO Programs 082.A-0526, 084.D-0719, 088.D-0222, 184.D-1140, and 386.D-0966); the Gemini Observatory, Cerro Pachon, Chile (Gemini Programs GS-2010A-Q-14 and GS-2010A-Q-38); the Magellan 6.5 m telescopes at Las Campanas Observatory; and the SOAR telescope.Tables 1-5 and Appendix A are available in electronic form at http

  4. Green Architecture

    NASA Astrophysics Data System (ADS)

    Lee, Seung-Ho

    Today, the environment has become a main subject in lots of science disciplines and the industrial development due to the global warming. This paper presents the analysis of the tendency of Green Architecture in France on the threes axes: Regulations and Approach for the Sustainable Architecture (Certificate and Standard), Renewable Materials (Green Materials) and Strategies (Equipments) of Sustainable Technology. The definition of 'Green Architecture' will be cited in the introduction and the question of the interdisciplinary for the technological development in 'Green Architecture' will be raised up in the conclusion.

  5. Open-source Peer-to-Peer Environment to Enable Sensor Web Architecture: Application to Geomagnetic Observations and Modeling

    NASA Astrophysics Data System (ADS)

    Holland, M.; Pulkkinen, A.

    2007-12-01

    -reported values. Remote "browsing" peers access these modeling-run results within the Environment, but also have the option to access the sensors directly. We expect that this preparatory work will benefit the LWS/Geospace program, as real-time geomagnetic observations are relevant to Sun-Earth Connection studies.

  6. On the search for evidence of fast mode compressions in the near-earth tail - ISEE observations

    NASA Technical Reports Server (NTRS)

    Moortgat, K. T.; Cattell, C. A.; Mozer, F. S.; Elphic, R.

    1990-01-01

    A search for earthward propagating fast mode compressions in the near-earth tail has been conducted. ISEE electric and magnetic field data were studied for substorm and quiet times when the spacecraft was close to the neutral sheet, near midnight, and at radial distances of 5.5 to 13 R(E) (earth radii). Due to ISEE orbit characteristics, the set of events covered 12.5 hours, during which time the satellite remained between 8.5 and 13 R(E). Contrary to earlier ideas, no evidence for fast mode compression waves was found during the substorm events studied here, since plasma data and spacecraft potential data showed no density increases at the times of rapid magnetic field increases. For the one compression event for which a temporal offset between the ISEE 1 and ISEE 2 magnetic field structures could be clearly determined, the propagation velocity was about 140 km/s, well below the fast mode speed of about 400 km/s for the measured composition. During substorm events, the largest convection flows were earthward with magnitudes of 100-350 km/sec.

  7. Spectral variation in the supergiant fast X-ray transient SAX J1818.6-1703 observed by XMM-Newton and INTEGRAL

    NASA Astrophysics Data System (ADS)

    Boon, C. M.; Bird, A. J.; Hill, A. B.; Sidoli, L.; Sguera, V.; Goossens, M. E.; Fiocchi, M.; McBride, V. A.; Drave, S. P.

    2016-03-01

    We present the results of a 30 ks XMM-Newton observation of the supergiant fast X-ray transient (SFXT) SAX J1818.6-1703 - the first in-depth soft X-ray study of this source around periastron. INTEGRAL observations shortly before and after the XMM-Newton observation show the source to be in an atypically active state. Over the course of the XMM-Newton observation, the source shows a dynamic range of ˜100 with a luminosity greater than 1 × 1035 erg s-1 for the majority of the observation. After an ˜6 ks period of low-luminosity (˜1034 erg s-1) emission, SAX J1818.6-1703 enters a phase of fast flaring activity, with flares ˜250 s long, separated by ˜2 ks. The source then enters a larger flare event of higher luminosity and ˜8 ks duration. Spectral analysis revealed evidence for a significant change in spectral shape during the observation with a photon index varying from Γ ˜ 2.5 during the initial low-luminosity emission phase, to Γ ˜ 1.9 through the fast flaring activity, and a significant change to Γ ˜ 0.3 during the main flare. The intrinsic absorbing column density throughout the observation (nH ˜ 5 × 1023 cm-2) is among the highest measured from an SFXT, and together with the XMM-Newton and INTEGRAL luminosities, consistent with the neutron star encountering an unusually dense wind environment around periastron. Although other mechanisms cannot be ruled out, we note that the onset of the brighter flares occurs at 3 × 1035erg s-1, a luminosity consistent with the threshold for the switch from a radiative-dominated to Compton cooling regime in the quasi-spherical settling accretion model.

  8. Controlling chaos in a fast diode resonator using extended time-delay autosynchronization: Experimental observations and theoretical analysis.

    PubMed

    Sukow, David W.; Bleich, Michael E.; Gauthier, Daniel J.; Socolar, Joshua E. S.

    1997-12-01

    We stabilize unstable periodic orbits of a fast diode resonator driven at 10.1 MHz (corresponding to a drive period under 100 ns) using extended time-delay autosynchronization. Stabilization is achieved by feedback of an error signal that is proportional to the difference between the value of a state variable and an infinite series of values of the state variable delayed in time by integral multiples of the period of the orbit. The technique is easy to implement electronically and it has an all-optical counterpart that may be useful for stabilizing the dynamics of fast chaotic lasers. We show that increasing the weights given to temporally distant states enlarges the domain of control and reduces the sensitivity of the domain of control on the propagation delays in the feedback loop. We determine the average time to obtain control as a function of the feedback gain and identify the mechanisms that destabilize the system at the boundaries of the domain of control. A theoretical stability analysis of a model of the diode resonator in the presence of time-delay feedback is in good agreement with the experimental results for the size and shape of the domain of control. (c) 1997 American Institute of Physics. PMID:12779682

  9. Project Integration Architecture: Architectural Overview

    NASA Technical Reports Server (NTRS)

    Jones, William Henry

    2001-01-01

    The Project Integration Architecture (PIA) implements a flexible, object-oriented, wrapping architecture which encapsulates all of the information associated with engineering applications. The architecture allows the progress of a project to be tracked and documented in its entirety. By being a single, self-revealing architecture, the ability to develop single tools, for example a single graphical user interface, to span all applications is enabled. Additionally, by bringing all of the information sources and sinks of a project into a single architectural space, the ability to transport information between those applications becomes possible, Object-encapsulation further allows information to become in a sense self-aware, knowing things such as its own dimensionality and providing functionality appropriate to its kind.

  10. Strategies to Make Ramadan Fasting Safer in Type 2 Diabetics: A Systematic Review and Network Meta-analysis of Randomized Controlled Trials and Observational Studies.

    PubMed

    Lee, Shaun Wen Huey; Lee, Jun Yang; Tan, Christina San San; Wong, Chee Piau

    2016-01-01

    Ramadan is the holy month for Muslims whereby they fast from predawn to after sunset and is observed by all healthy Muslim adults as well as a large population of type 2 diabetic Muslims.To determine the comparative effectiveness of various strategies that have been used for type 2 diabetic Muslim who fast during Ramadan.A systematic review and network meta-analysis of randomized controlled studies (RCT) as well as observational studies for patients with type 2 diabetes who fasted during Ramadan was conducted. Eight databases were searched from January 1980 through October 2015 for relevant studies. Two reviewers independently screened and assessed study for eligibility, assessed the risk of bias, and extracted relevant data. A network meta-analysis for each outcome was fitted separately, combining direct and indirect evidence for each comparison.Twenty-nine studies, 16 RCTs and 13 observational studies each met the inclusion criteria. The most common strategy used was drug changes during the Ramadan period, which found that the use of DPP-4 (Dipeptidyl peptidase inhibitor -4) inhibitors were associated with a reduction in incidence of experiencing hypoglycemia during Ramadan in both RCTs (pooled relative risk: 0.56; 95% confidence interval: 0.44-0.72) as well as in observational studies (pooled relative risk: 0.27; 0.09-0.75). Ramadan-focused education was shown to be beneficial in reducing hypoglycemia in observational studies but not RCTs (0.25 versus 1.00). Network meta-analyses suggest that incretin mimetics can reduce the risk of hypoglycemia by nearly 1.5 times.The newer antidiabetic agents appear to lower the risk of hypoglycemia and improved glycemic control when compared with sulfonylureas. Ramadan-focused education shows to be a promising strategy but more rigorous examination from RCTs are required. PMID:26765440

  11. Fast stochastic variability study of two SU UMa systems V1504 Cyg and V344 Lyr observed by Kepler satellite

    NASA Astrophysics Data System (ADS)

    Dobrotka, A.; Ness, J.-U.; Bajčičáková, I.

    2016-07-01

    We analysed Kepler data of two similar dwarf novae V344 Lyr and V1504 Cyg in order to study optical fast stochastic variability (flickering) by searching for characteristic break frequencies in their power density spectra. Two different stages of activity were analysed separately, i.e. regular outbursts and quiescence. Both systems show similar behaviour during both activity stages. The quiescent power density spectra show a dominant low break frequency which is also present during outburst with a more or less stable value in V344 Lyr while it is slightly higher in V1504 Cyg. The origin of this variability is probably the whole accretion disc. Both outburst power density spectra show additional high-frequency components which we interpret as generated by the rebuilt inner disc that was truncated during quiescence. Moreover, V344 Lyr shows the typical linear rms-flux relation which is strongly deformed by a possible negative superhump variability.

  12. Swift observes a new outburst from the Supergiant Fast X-ray Transient SAX J1818.6-1703

    NASA Astrophysics Data System (ADS)

    Romano, P.; Barthelmy, S.; Sidoli, L.; Vercellone, S.; Burrows, D. N.; Chester, M. M.; Esposito, P.; Evans, P. A.; Gehrels, N.; Kennea, J. A.; Krimm, H. A.; La Parola, V.

    2009-09-01

    The Swift/BAT triggered on a new outburst from the Supergiant Fast X-ray Transient SAX J1818.6-1703 on 2009 September 5 at 11:15:15. Using the data set from T-239 to T+963 s, the mask-weighted light curve shows weak on-going emission at the start of the data at T-240 sec with a slow rise to a peak (of 0.06 ph/cm2/s in the 15-350 keV band) somewhere around T+200 s, and then slowly decreasing out past the end of the collected event-by-event data at T+963 s.

  13. In Situ TEM Observations of Sn-Containing Silicon Nanowires Undergoing Reversible Pore Formation Due to Fast Lithiation/Delithiation Kinetics

    SciTech Connect

    Lu, Xiaotang; Bogart, Timothy D.; Gu, Meng; Wang, Chong M.; Korgel, Brian

    2015-09-03

    In situ transmission electron microscopy (TEM) studies were carried out to observe directly in real time the lithiation and delithiation of silicon (Si) nanowires with significant amounts of tin (Sn). The incorporation of Sn significantly enhances the lithiation rate compared to typical Si nanowires. For instance, surface diffusion is enhanced by two orders of magnitude and the bulk lithiation rate by one order of magnitude, resulting in a sequential surface-then-core lithiation mechanism. Pore formation was observed in the nanowires during delithiation, most likely as a result of the fast delithiation kinetics of the nanowires. Pore formation was reversible and the pores disappeared during subsequent lithiation. When an amorphous Si shell was applied to the nanowires, pore formation was not observed during the in situ TEM experimences. Ex situ TEM analysis of Sn-containing Si nanowires cycled in coin cell batteries also showed that the application of an a-Si shell significantly retards pore formation in these nanowires.

  14. PICNIC Architecture.

    PubMed

    Saranummi, Niilo

    2005-01-01

    The PICNIC architecture aims at supporting inter-enterprise integration and the facilitation of collaboration between healthcare organisations. The concept of a Regional Health Economy (RHE) is introduced to illustrate the varying nature of inter-enterprise collaboration between healthcare organisations collaborating in providing health services to citizens and patients in a regional setting. The PICNIC architecture comprises a number of PICNIC IT Services, the interfaces between them and presents a way to assemble these into a functioning Regional Health Care Network meeting the needs and concerns of its stakeholders. The PICNIC architecture is presented through a number of views relevant to different stakeholder groups. The stakeholders of the first view are national and regional health authorities and policy makers. The view describes how the architecture enables the implementation of national and regional health policies, strategies and organisational structures. The stakeholders of the second view, the service viewpoint, are the care providers, health professionals, patients and citizens. The view describes how the architecture supports and enables regional care delivery and process management including continuity of care (shared care) and citizen-centred health services. The stakeholders of the third view, the engineering view, are those that design, build and implement the RHCN. The view comprises four sub views: software engineering, IT services engineering, security and data. The proposed architecture is founded into the main stream of how distributed computing environments are evolving. The architecture is realised using the web services approach. A number of well established technology platforms and generic standards exist that can be used to implement the software components. The software components that are specified in PICNIC are implemented in Open Source. PMID:16160218

  15. Observations on the quantitation of the phosphate content of peptides by fast-atom bombardment mass spectrometry.

    PubMed

    Poulter, L; Ang, S G; Williams, D H; Cohen, P

    1987-07-29

    Equimolar mixtures of the phosphorylated and dephosphorylated forms of several peptides have been subjected to fast-atom bombardment mass spectrometry (FABMS), to investigate whether the stoichiometry of phosphorylation can be determined from the relative molecular-ion abundances of the phospho and dephospho derivatives. It is concluded that quantitation can be achieved for peptides with large positive or negative hydrophobicity/hydrophilicity indices (delta F values) where addition of a phosphate group does not alter the distribution of the peptide within the matrix significantly. For peptides with small positive or negative delta F values, phosphopeptides tend to be partially suppressed by their dephosphorylated counterparts. Suppression can be partially or totally overcome by conversion of the peptide to a hydrophobic derivative, and by the selection of an appropriate matrix. Alternatively, addition of a very strong acid, perchloric acid, can even reverse the original suppression effect. This last effect is believed to be due to the increased ionic strength in the matrix, which forces a relatively hydrophilic analyte to the matrix surface; and the ability of such a phosphorylated analyte to form a more stable gas-phase cation. PMID:3038197

  16. Measurement of Field Aligned Electron Density Distribution, Ducts, and Z-mode Cavities from the Ducted and Nonducted Fast Z-mode Echoes Observed on IMAGE

    NASA Astrophysics Data System (ADS)

    Mayank, K.; Sonwalkar, V. S.

    2012-12-01

    We present a method to measure geomagnetic field(B0) aligned electron density(Ne) distribution, ducts, and Z-mode(ZM) cavities from the ducted and nonducted fast ZM echoes observed from radio sounding at 50-1000 kHz by RPI/IMAGE. Roughly 2000 cases of fast ZM echoes have been observed on the IMAGE satellite in the altitude range of ˜800-10,000 km, invariant latitude range of 30° - 70°, and at all MLTs. In this paper we present two case studies: (1) nonducted C-D type fast ZM echoes observed on 19 June 2004 (L=3.81, Altitude=5340km, MLT=18.7), and (2) ducted C-D type fast ZM echoes observed on 10 July 2001 (L = 2.68, Altitude˜4100 km, MLT = 17.7). Nonducted fast ZM C(D) trace is obtained when the ZM signal is reflected at an altitude below(above) the satellite altitude, when the satellite is within the ZM cavities, at which fZ ˜ f, where fZ is the ZM cutoff frequency and f is the wave frequency. In the case of nonducted echoes, (1) the lower(upper) cutoff frequency of C-trace is less(more) than that of D-trace, (2) no higher trace (e.g., C+D, C+2D) exists, and (3) C and D traces are discrete i.e,. the echoes, at each frequency, are limited to 2-3 bins. From ray tracing calculations, we obtain four nonducted fast ZM echoes, each reflecting from locations where fZ ˜ f. Three of the echoes retrace their paths after reflection and one forms a loop. The shape of fZ contours in the magnetic meridional plane, the injected wave frequency(f), the location of the satellite with respect to fZ contours, the change in the size of the refractive index surfaces with altitude, and the Snell's law explains the generation of retracing and looping echoes. From the inversion of tg-f dispersion we obtain the field aligned Ne distribution both above and below the satellite from an altitude of ˜1500 km-10,000 km. The ducted echoes, obtained when the satellite is within a ZM cavity, are characterized by (1) integral relationship of echo time-delays (tg) of lower time delay traces (e

  17. Preliminary Results From Observing The Fast Stardust Sample Return Capsule Entry In Earth's Atmosphere On January 15, 2006.

    NASA Astrophysics Data System (ADS)

    Jenniskens, P.; Jordan, D.; Kontinos, D.; Wright, M.; Olejniczak, J.; Raiche, G.; Wercinski, P.; Schilling, E.; Taylor, M.; Rairden, R.; Stenbaek-Nielsen, H.; McHarg, M. G.; Abe, S.; Winter, M.

    2006-08-01

    In order for NASA's Stardust mission to return a comet sample to Earth, the probe was put in an orbit similar to that of Near Earth Asteroids. As a result, the reentry in Earth's atmosphere on January 15, 2006, was the fastest entry ever for a NASA spacecraft, with a speed of 12.8 km/s, similar to that of natural fireballs. A new thermal protection material, PICA, was used to protect the sample, a material that may have a future as thermal protection for the Crew Return Vehicle or for future planetary missions. An airborne and ground-based observing campaign, the "Stardust Hyperseed MAC", was organized to observe the reentry under good observing conditions, with spectroscopic and imaging techniques commonly used for meteor observations (http:// reentry.arc.nasa.gov). A spectacular video of the reentry was obtained. The spectroscopic observations measure how much light was generated in the shock wave, how that radiation added to heating the surface, how the PICA ablated as a function of altitude, and how the carbon reacted with the shock wave to form CN, a possible marker of prebiotic chemistry in natural meteors. In addition, the observations measured a transient signal of zinc and potassium early in the trajectory, from the ablation of a white paint layer that had been applied to the heat shield for thermal control. Implications for sample return and the exploration of atmospheres in future planetary missions will be discussed.

  18. IAIMS Architecture

    PubMed Central

    Hripcsak, George

    1997-01-01

    Abstract An information system architecture defines the components of a system and the interfaces among the components. A good architecture is essential for creating an Integrated Advanced Information Management System (IAIMS) that works as an integrated whole yet is flexible enough to accommodate many users and roles, multiple applications, changing vendors, evolving user needs, and advancing technology. Modularity and layering promote flexibility by reducing the complexity of a system and by restricting the ways in which components may interact. Enterprise-wide mediation promotes integration by providing message routing, support for standards, dictionary-based code translation, a centralized conceptual data schema, business rule implementation, and consistent access to databases. Several IAIMS sites have adopted a client-server architecture, and some have adopted a three-tiered approach, separating user interface functions, application logic, and repositories. PMID:9067884

  19. IAIMS architecture.

    PubMed

    Hripcsak, G

    1997-01-01

    An information system architecture defines the components of a system and the interfaces among the components. A good architecture is essential for creating an Integrated Advanced Information Management System (IAIMS) that works as an integrated whole yet is flexible enough to accommodate many users and roles, multiple applications, changing vendors, evolving user needs, and advancing technology. Modularity and layering promote flexibility by reducing the complexity of a system and by restricting the ways in which components may interact. Enterprise-wide mediation promotes integration by providing message routing, support for standards, dictionary-based code translation, a centralized conceptual data schema, business rule implementation, and consistent access to databases. Several IAIMS sites have adopted a client-server architecture, and some have adopted a three-tiered approach, separating user interface functions, application logic, and repositories. PMID:9067884

  20. Detection of special nuclear material by observation of delayed neutrons with a novel fast neutron composite detector

    NASA Astrophysics Data System (ADS)

    Mayer, Michael; Nattress, Jason; Barhoumi Meddeb, Amira; Foster, Albert; Trivelpiece, Cory; Rose, Paul; Erickson, Anna; Ounaies, Zoubeida; Jovanovic, Igor

    2015-10-01

    Detection of shielded special nuclear material is crucial to countering nuclear terrorism and proliferation, but its detection is challenging. By observing the emission of delayed neutrons, which is a unique signature of nuclear fission, the presence of nuclear material can be inferred. We report on the observation of delayed neutrons from natural uranium by using monoenergetic photons and neutrons to induce fission. An interrogating beam of 4.4 MeV and 15.1 MeV gamma-rays and neutrons was produced using the 11B(d,n-γ)12C reaction and used to probe different targets. Neutron detectors with complementary Cherenkov detectors then discriminate material undergoing fission. A Li-doped glass-polymer composite neutron detector was used, which displays excellent n/ γ discrimination even at low energies, to observe delayed neutrons from uranium fission. Delayed neutrons have relatively low energies (~0.5 MeV) compared to prompt neutrons, which makes them difficult to detect using recoil-based detectors. Neutrons were counted and timed after the beam was turned off to observe the characteristic decaying time profile of delayed neutrons. The expected decay of neutron emission rate is in agreement with the common parametrization into six delayed neutron groups.

  1. Observing conformations of single FoF1-ATP synthases in a fast anti-Brownian electrokinetic trap

    NASA Astrophysics Data System (ADS)

    Su, Bertram; Düser, Monika G.; Zarrabi, Nawid; Heitkamp, Thomas; Starke, Ilka; Börsch, Michael

    2015-03-01

    To monitor conformational changes of individual membrane transporters in liposomes in real time, we attach two fluorophores to selected domains of a protein. Sequential distance changes between the dyes are recorded and analyzed by Förster resonance energy transfer (FRET). Using freely diffusing membrane proteins reconstituted in liposomes, observation times are limited by Brownian motion through the confocal detection volume. A. E. Cohen and W. E. Moerner have invented and built microfluidic devices to actively counteract Brownian motion of single nanoparticles in electrokinetic traps (ABELtrap). Here we present a version of an ABELtrap with a laser focus pattern generated by electro-optical beam deflectors and controlled by a programmable FPGA. This ABELtrap could hold single fluorescent nanobeads for more than 100 seconds, increasing the observation times of a single particle more than 1000-fold. Conformational changes of single FRET-labeled membrane enzymes FoF1-ATP synthase can be detected in the ABELtrap.

  2. FAST EXTREME-ULTRAVIOLET DIMMING ASSOCIATED WITH A CORONAL JET SEEN IN MULTI-WAVELENGTH AND STEREOSCOPIC OBSERVATIONS

    SciTech Connect

    Lee, K.-S.; Moon, Y.-J.; Lee, Jin-Yi; Innes, D. E.; Shibata, K.; Park, Y.-D.

    2013-03-20

    We have investigated a coronal jet observed near the limb on 2010 June 27 by the Hinode/X-Ray Telescope (XRT), EUV Imaging Spectrograph (EIS), and Solar Optical Telescope (SOT), and by the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA), and on the disk by STEREO-A/EUVI. From EUV (AIA and EIS) and soft X-ray (XRT) images we have identified both cool and hot jets. There was a small loop eruption seen in Ca II images of the SOT before the jet eruption. We found that the hot jet preceded its associated cool jet by about 2 minutes. The cool jet showed helical-like structures during the rising period which was supported by the spectroscopic analysis of the jet's emission. The STEREO observation, which enabled us to observe the jet projected against the disk, showed dimming at 195 A along a large loop connected to the jet. We measured a propagation speed of {approx}800 km s{sup -1} for the dimming front. This is comparable to the Alfven speed in the loop computed from a magnetic field extrapolation of the photospheric field measured five days earlier by the SDO/Helioseismic and Magnetic Imager, and the loop densities obtained from EIS Fe XIV {lambda}264.79/274.20 line ratios. We interpret the dimming as indicating the presence of Alfvenic waves initiated by reconnection in the upper chromosphere.

  3. Architectural Illusion.

    ERIC Educational Resources Information Center

    Doornek, Richard R.

    1990-01-01

    Presents a lesson plan developed around the work of architectural muralist Richard Haas. Discusses the significance of mural painting and gives key concepts for the lesson. Lists class activities for the elementary and secondary grades. Provides a photograph of the Haas mural on the Fountainbleau Hilton Hotel, 1986. (GG)

  4. Architectural Treasures.

    ERIC Educational Resources Information Center

    Pietropola, Anne

    1998-01-01

    Presents an art lesson for eighth-grade students in which they created their own architectural structures. Stresses a strong discipline-based introduction using slide shows of famous buildings, large metropolitan cities, and 35,00 years of homes. Reports the lesson spanned two weeks. Includes a diagram, directions, and specifies materials. (CMK)

  5. Architectural Drafting.

    ERIC Educational Resources Information Center

    Davis, Ronald; Yancey, Bruce

    Designed to be used as a supplement to a two-book course in basic drafting, these instructional materials consisting of 14 units cover the process of drawing all working drawings necessary for residential buildings. The following topics are covered in the individual units: introduction to architectural drafting, lettering and tools, site…

  6. Architectural Tops

    ERIC Educational Resources Information Center

    Mahoney, Ellen

    2010-01-01

    The development of the skyscraper is an American story that combines architectural history, economic power, and technological achievement. Each city in the United States can be identified by the profile of its buildings. The design of the tops of skyscrapers was the inspiration for the students in the author's high-school ceramic class to develop…

  7. Slow and fast narrow spectra aurora E region echoes during the March 17, 2015 storm at mid latitudes. Multi-static, multi-frequency radar observations

    NASA Astrophysics Data System (ADS)

    Chau, Jorge; St-Maurice, Jean-Pierre

    2016-07-01

    Coherent E region echoes were observed at midlatitudes during the March 17, 2015 storm. The observations came from multi-static, multi-frequency, wide-field of view radars operating at 32.55 and 36.2 MHz in northern Germany. Each of the three receiver stations used, two in monostatic and one in bistatic modes, allow interferometry. These radars systems are devoted primarily to the measurement of mesospheric winds from specular meteor echoes. However during this storm, the strongest of the current solar cycle, strong Radar Aurora echoes were observed during the day for more than four hours. Here we present the main features observed, with a specific emphasis on echoes presenting narrow spectra with slower (around 180 m/s) and faster (as fast as 1600 m/s) Doppler velocities, than nominal typical ion-acoustic velocity expected to be between 400 and 800 m/s. We find that in both types of echoes the range vs. time slopes are between 800 and 1400 m/s. They agree rather well with the Doppler velocity for the narrow fast types but do not agree at all in the narrow slow spectral case. In both instances, the echoes are organized in localized horizontal structures with a range extent typically between 50 and 80 km. The fast-narrow structures tend to occur at higher altitudes than the well-known Farley-Buneman echoes, while the slow-narrow structures occur at lower altitudes (lower than 95 km). Both echo types come from regions with relatively small flow angles. Moreover the altitude of all echoes went down after 16:15 UT with the small-narrow echoes acquiring even smaller Doppler velocities. In large part thanks to the echo localization made feasible by interferometry, these new features are shedding some new important perspective on our understanding of auroral E-region radar echoes, particularly when it comes to spectra classified in the past as "Type III" and "Type IV" echoes.

  8. Swift observes a new outburst from the Supergiant Fast X-ray Transient AX J1845.0-0433

    NASA Astrophysics Data System (ADS)

    Romano, P.; Barthelmy, S. D.; Chester, M. M.; Oates, S. R.; Burrows, D. N.; Esposito, P.; Evans, P. A.; Kennea, J. A.; Krimm, H. A.; Mangano, V.; Vercellone, S.; Gehrels, N.

    2012-05-01

    Swift observed a new outburst from the SFXT AX J1845.0-0433/IGR J18450-0435. The Swift/BAT triggered on it on 2012 May 05 at 01:44:39 UT (image trigger=521567). Using the BAT data set from T-239 to T+963 s from the recent telemetry downlink, we report that the mask-weighted light curve shows the source already in outburst when it came into the BAT FoV during a pre-planned slew. Emission continues at the 0.013 ph/cm2/s level out past T+963 s.

  9. Swift observes a new outburst from the Supergiant Fast X-ray Transient AX J1841.0-0536

    NASA Astrophysics Data System (ADS)

    Romano, P.; Barthelmy, S. D.; Kennea, J. A.; Esposito, P.; Evans, P. A.; Mangano, V.; Palmer, D. M.; Burrows, D. N.; Chester, M. M.; Krimm, H.; Ukwatta, T. N.; Vercellone, S.; Gehrels, N.

    2012-06-01

    Swift observed a new outburst from the SFXT AX J1841.0-0536. The Swift/BAT triggered on it on 2012 Jun 14 at 19:11:51 UT (image trigger 524364). Swift performed an immediate slew. Using the BAT data set from T-239 to T+963 s from recent telemetry downlinks, we report that the mask-weighted light curve shows the source was active when it came into the BAT FoV (at T-100 s) during a preplanned slew.

  10. EISCAT-Cluster observations of quiet-time near-Earth magnetotail fast flows and their signatures in the ionosphere

    NASA Astrophysics Data System (ADS)

    Pitkänen, T.; Aikio, A. T.; Amm, O.; Kauristie, K.; Nilsson, H.; Kaila, K. U.

    2011-02-01

    We report observations of a sequence of quiet-time Earthward bursty bulk flows (BBFs) measured by the Cluster spacecraft in the near-tail plasma sheet (XGSM ~ -12 to -14 RE) in the evening sector, and by simultaneous high-resolution measurements in the northern conjugate ionosphere by the EISCAT radars, a MIRACLE all-sky camera and magnetometers, as well as a meridian-scanning photometer (MSP) in the Scandinavian sector on 17 October 2005. The BBFs at Cluster show signatures that are consistent with the plasma "bubble" model (Chen and Wolf, 1993, 1999), e.g. deflection and compression of the ambient plasma in front of the Earthward moving bubble, magnetic signatures of a flow shear region, and the proper flows inside the bubble. In addition, clear signatures of tailward return flows around the edges of the bubble can be identified. The duskside return flows are associated with significant decrease in plasma density, giving support to the recent suggestion by Walsh et al. (2009) of formation of a depleted wake. However, the same feature is not seen for the dawnside return flows, but rather an increase in density. In the ionosphere, EISCAT and optical measurements show that each of the studied BBFs is associated with an auroral streamer that starts from the vicinity of the polar cap boundary, intrudes equatorward, brakes at 68-70° aacgm MLAT and drifts westward along the proton oval. Within the streamer itself and poleward of it, the ionospheric plasma flow has an equatorward component, which is the ionospheric manifestation of the Earthward BBF channel. A sharp velocity shear appears at the equatorward edge of a streamer. We suggest that each BBF creates a local velocity shear in the ionosphere, in which the plasma flow poleward of and inside the streamer is in the direction of the streamer and southeastward. A northwestward return flow is located on the equatorward side. The return flow is associated with decreased plasma densities both in the ionosphere and in

  11. Brain architecture: a design for natural computation.

    PubMed

    Kaiser, Marcus

    2007-12-15

    Fifty years ago, John von Neumann compared the architecture of the brain with that of the computers he invented and which are still in use today. In those days, the organization of computers was based on concepts of brain organization. Here, we give an update on current results on the global organization of neural systems. For neural systems, we outline how the spatial and topological architecture of neuronal and cortical networks facilitates robustness against failures, fast processing and balanced network activation. Finally, we discuss mechanisms of self-organization for such architectures. After all, the organization of the brain might again inspire computer architecture. PMID:17855223

  12. Fast rotor flux control of direct-field-oriented induction motor operating at maximum efficiency using adaptive rotor flux observer

    SciTech Connect

    Matsuse, Kouki; Katsuta, Seiji; Tsukakoshi, Masahiko; Ohta, Masaru; Huang, L.

    1995-12-31

    A method of using an adaptive rotor flux observer to rapidly control the rotor flux of direct-field-oriented induction motors driven by a deadbeat rotor flux controller has been developed. The method ensures maximum efficiency in the steady state without degradation of the dynamic response. Furthermore, to solve the problem of flux current variations that arise from small errors in the measurement of the stator voltage and current, a flux current reference is calculated from the appropriate rotor flux in the steady state. Simulation and experimental results for an induction motor have demonstrated that this method yields the maximum efficiency and good speed response to changes in both torque and motor speed without any degradation in the transient characteristics.

  13. Observation of Abrupt- and Fast-rising SOL Current during Trigger Phase of ELMs in DIII-D Tokamak

    SciTech Connect

    H. Takahashi; E.D. Fredrickson; M.J. Schaffer; M.E. Austin; N.H. Brooks; T.E. Evans; G.L. Jackson; L.L. Lao; J.G. Watkins

    2005-06-27

    Extensive studies to date of edge localized modes (ELMs) have sought their origin inside the separatrix, i.e., MHD instability from steep gradients in the plasma edge, and examined their consequences outside the separatrix, i.e., transport of heat and particles in the scrape-off-layer (SOL) and divertors. Recent measurement by a high-speed scrape-off-layer current (SOLC) diagnostic may indicate that the ELM trigger process lies, in part, in the SOL. Thermoelectrically driven SOLC precedes, or co-evolves with, other parameters of the ELM process, and thus can potentially play a causal role: error field generated by non-axisymmetric SOLC, flowing in the immediate vicinity (approximately 1 cm) of the plasma edge, may contribute toward destabilizing MHD modes. The SOLC, observed concurrently with MHD activity, including ELMs, has been reported elsewhere.

  14. Flare Emission Onset in the Slow-Rise and Fast-Rise Phases of an Erupting Solar Filament Observed with TRACE

    NASA Technical Reports Server (NTRS)

    Sterling, A. C.; Moore, R. L.

    2005-01-01

    We observe the eruption of an active-region solar filament of 1998 July 11 using high time cadence and high spatial resolution EUV observations from the TRACE sareiii'ce, along with soft X-ray images from the soft X-ray telescope (SXT) on the Yohkoh satellite, hard X-ray fluxes from the BATSE instrument on the (CGRO) satellite and from the hard X-ray telescope (HXT) on Yohkoh, and ground-based magnetograms. We concentrate on the initiation of the eruption in an effort to understand the eruption mechanism. First the filament undergoes slow upward movement in a "slow rise" phase with an approximately constant velocity of approximately 15 km/s that lasts about 10-min, and then it erupts in a "fast-rise" phase, reaching a velocity of about 200 km/s in about 5-min, followed by a period of deceleration. EUV brightenings begin just before the start of the filament's slow rise, and remain immediately beneath the rising filament during the slow rise; initial soft X-ray brightenings occur at about the same time and location. Strong hard X-ray emission begins after the onset of the fast rise, and does not peak until the filament has traveled a substantial altitude (to a height about equal to the initial length of the erupting filament) beyond its initial location. Our observations are consistent with the slow-rise phase of the eruption resulting from the onset of "tether cutting" reconnection between magnetic fields beneath the filament, and the fast rise resulting from an explosive increase in the reconnection rate or by catastrophic destabilization of the overlying filament-carrying fields. About two days prior to the event new flux emerged near the location of the initial brightenings, and this recently- emerged flux could have been a catalyst for initiating the tether-cutting reconnection. With the exception of the initial slow rise, our findings qualitatively agree with the prediction for erupting-flux-rope height as a function of time in a model discussed by Chen

  15. Very high swelling and embrittlement observed in a Fe-18Cr-10Ni-Ti hexagonal fuel wrapper irradiated in the BOR-60 fast reactor

    SciTech Connect

    Neustroev, V. S.; Garner, Francis A.

    2008-09-01

    The highest void swelling level ever observed in an operating fast reactor component has been found after irradiation in BOR-60 with swelling in Kh18H10T (Fe-18Cr-10Ni-Ti) austenitic steel exceeding 50%. At such high swelling levels the steel has reached a terminal swelling rate of ~1%/dpa after a transient that depends on both dpa rate and irradiation temperature. The transient duration at the higher irradiation temperatures is as small as 10-13 dpa depending on which face was examined. When irradiated in a fast reactor such as BOR-60 with a rather low inlet temperature, most of the swelling occurs above the core center-plane and produces a highly asymmetric swelling loop when plotted vs. dpa. Voids initially harden the alloy but as the swelling level becomes significant the elastic moduli of the alloy decreases strongly with swelling, leading to the consequence that the steel actually softens with increasing swelling. This softening occurs even as the elongation decreases as a result of void linkage during deformation. Finally, the elongation decreases to zero with further increases of swelling. This very brittle failure is known to arise from segregation of nickel to void surfaces which induces a martensitic instability leading to a zero tearing modulus and zero deformation.

  16. A POSSIBLE DETECTION OF A FAST-MODE EXTREME ULTRAVIOLET WAVE ASSOCIATED WITH A MINI CORONAL MASS EJECTION OBSERVED BY THE SOLAR DYNAMICS OBSERVATORY

    SciTech Connect

    Zheng Ruisheng; Jiang Yunchun; Hong Junchao; Yang Jiayan; Bi Yi; Yang Liheng; Yang Dan

    2011-10-01

    'Extreme ultraviolet (EUV) waves' are large-scale wavelike transients often associated with coronal mass ejections (CMEs). In this Letter, we present a possible detection of a fast-mode EUV wave associated with a mini-CME observed by the Solar Dynamics Observatory. On 2010 December 1, a small-scale EUV wave erupted near the disk center associated with a mini-CME, which showed all the low corona manifestations of a typical CME. The CME was triggered by the eruption of a mini-filament, with a typical length of about 30''. Although the eruption was tiny, the wave had the appearance of an almost semicircular front and propagated at a uniform velocity of 220-250 km s{sup -1} with very little angular dependence. The CME lateral expansion was asymmetric with an inclination toward north, and the southern footprints of the CME loops hardly shifted. The lateral expansion resulted in deep long-duration dimmings, showing the CME extent. Comparing the onset and the initial speed of the CME, the wave was likely triggered by the rapid expansion of the CME loops. Our analysis confirms that the small-scale EUV wave is a true wave, interpreted as a fast-mode wave.

  17. Energy calibration issues in nuclear resonant vibrational spectroscopy: observing small spectral shifts and making fast calibrations

    PubMed Central

    Wang, Hongxin; Yoda, Yoshitaka; Dong, Weibing; Huang, Songping D.

    2013-01-01

    The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-57Fe-enriched [Fe4S4Cl4]= and 10%-57Fe and 90%-54Fe labeled [Fe4S4Cl4]= has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3–4 h to about 30 min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements. PMID:23955030

  18. FAST TRACK COMMUNICATION: Observation of the room temperature magnetoelectric effect in Dy doped BiFeO3

    NASA Astrophysics Data System (ADS)

    Uniyal, P.; Yadav, K. L.

    2009-01-01

    Polycrystalline Bi1-xDyxFeO3 (x = 0.0, 0.03, 0.05, 0.07 and 0.1) ceramics have been prepared via a mixed oxide route. The effect of Dy substitution on the dielectric, ferroelectric, and magnetic properties of the BiFeO3 multiferroic perovskite is studied. Experimental results suggest that in the Bi1-xDyxFeO3 system, increase of the Dy concentration leads to effective suppression of the spiral spin structure of BiFeO3, resulting in the appearance of net magnetization. An anomaly in the dielectric constant (ɛ) was observed in the vicinity of the antiferromagnetic transition temperature. All compositions show saturated polarization-field (P-E) curves. As a result, improved multiferroic properties of Bi0.9Dy0.1FeO3 ceramics with remnant polarization and magnetization (2Pr and 2Mr) of 7.98 µC cm-2 and 0.024 emu g-1, respectively, were established. An enhancement in remnant polarization after poling the samples in the magnetic field was evidence of magnetoelectric coupling at room temperature.

  19. A reconfigurable multicarrier demodulator architecture

    NASA Technical Reports Server (NTRS)

    Kwatra, S. C.; Jamali, M. M.

    1991-01-01

    An architecture based on parallel and pipline design approaches has been developed for the Frequency Division Multiple Access/Time Domain Multiplexed (FDMA/TDM) conversion system. The architecture has two main modules namely the transmultiplexer and the demodulator. The transmultiplexer has two pipelined modules. These are the shared multiplexed polyphase filter and the Fast Fourier Transform (FFT). The demodulator consists of carrier, clock, and data recovery modules which are interactive. Progress on the design of the MultiCarrier Demodulator (MCD) using commercially available chips and Application Specific Integrated Circuits (ASIC) and simulation studies using Viewlogic software will be presented at the conference.

  20. Frame architecture for video servers

    NASA Astrophysics Data System (ADS)

    Venkatramani, Chitra; Kienzle, Martin G.

    1999-11-01

    Video is inherently frame-oriented and most applications such as commercial video processing require to manipulate video in terms of frames. However, typical video servers treat videos as byte streams and perform random access based on approximate byte offsets to be supplied by the client. They do not provide frame or timecode oriented API which is essential for many applications. This paper describes a frame-oriented architecture for video servers. It also describes the implementation in the context of IBM's VideoCharger server. The later part of the paper describes an application that uses the frame architecture and provides fast and slow-motion scanning capabilities to the server.

  1. Angle-differential observation of plasmon electrons in the double-differential cross-section spectra of fast-ion-induced electron ejection from C60

    NASA Astrophysics Data System (ADS)

    Kelkar, A. H.; Gulyás, L.; Tribedi, Lokesh C.

    2015-11-01

    We report on the measurement of double-differential distribution of soft electron emission from C60 fullerene, induced by a fast-moving Coulomb field of 76 MeV energy bare fluorine ions. A broad "plasmon-electron" peak, riding on the Coulomb-ionization continuum, is observed due to the deexcitation of the giant dipole plasmon resonance state in C60. The angular distribution of the plasmon electrons goes through a dip around 90°, which is contrary to that observed in ion-atom collisions measured in situ, indicating the alignment of the induced dipole moment along the projectile beam direction. A model based on the photoelectron angular distribution which is modified due to the ion-induced postcollisional interaction provides an excellent agreement with the observed asymmetric distribution. The distribution smoothly changes from a dip at 90° to a peak with the variation of ejected electron energy indicating transition from a collective plasmon behavior of the whole system to a single ion-atom interaction. The single-differential cross section was also derived, which preserves the signature of the collective excitation.

  2. XMM-Newton and NuSTAR joint observation of the periodic Supergiant Fast X-ray Transient IGR J11215-5952

    NASA Astrophysics Data System (ADS)

    Sidoli, L.; Paizis, A.; Sguera, V.

    2016-06-01

    IGRJ11215-5952 is the only Supergiant Fast X-ray Transient showing periodic outbursts (every 165 days, the orbital period of the system). The driving mechanism causing the transient X-ray emission in this sub-class of High Mass X-ray Binaries is still a matter of debate, after 10 years from the discovery of the class. To disentangle between magnetar-like neutron stars from models requiring more usual neutron star magnetic fields (1E12G), we observed the SFXT pulsar IGRJ11215-5952 with XMM-Newton coordinated with NuSTAR on 2016, February 14, during the expected peak of the outburst, for a net exposure time of 20 ks. The source was indeed caught in outburst (1E36 erg/s), with several bright flares repeating quasi-periodically with timescales of a few thousand seconds, spanning a dynamic range of two orders of magnitude. The overlapping observation with both XMM-Newton and NuSTAR enabled the study of the simultaneous broad band spectrum from 0.3 to 78 keV. The work is still in progress, given the extreme variability of the X-ray emission. X-ray pulsations were detected at 187.14 s, consistent with the last XMM-Newton observation, performed in 2007. We will discuss XMM+NuSTAR results in light of the different models proposed to explain the SFXTs behavior.

  3. How architecture wins technology wars.

    PubMed

    Morris, C R; Ferguson, C H

    1993-01-01

    Signs of revolutionary transformation in the global computer industry are everywhere. A roll call of the major industry players reads like a waiting list in the emergency room. The usual explanations for the industry's turmoil are at best inadequate. Scale, friendly government policies, manufacturing capabilities, a strong position in desktop markets, excellent software, top design skills--none of these is sufficient, either by itself or in combination, to ensure competitive success in information technology. A new paradigm is required to explain patterns of success and failure. Simply stated, success flows to the company that manages to establish proprietary architectural control over a broad, fast-moving, competitive space. Architectural strategies have become crucial to information technology because of the astonishing rate of improvement in microprocessors and other semiconductor components. Since no single vendor can keep pace with the outpouring of cheap, powerful, mass-produced components, customers insist on stitching together their own local systems solutions. Architectures impose order on the system and make the interconnections possible. The architectural controller is the company that controls the standard by which the entire information package is assembled. Microsoft's Windows is an excellent example of this. Because of the popularity of Windows, companies like Lotus must conform their software to its parameters in order to compete for market share. In the 1990s, proprietary architectural control is not only possible but indispensable to competitive success. What's more, it has broader implications for organizational structure: architectural competition is giving rise to a new form of business organization. PMID:10124636

  4. Will architecture win the technology wars?

    PubMed

    Alberthal, L; Manzi, J; Curtis, G; Davidow, W H; Timko, J W; Nadler, D; Davis, L L

    1993-01-01

    Success today flows to the company that establishes proprietary architectural control over a broad, fast-moving, competitive space, Charles R. Morris and Charles H. Ferguson claim in "How Architecture Wins Technology Wars" (March-April 1993). No single vendor can keep pace with the outpouring of cheap, powerful, mass-produced components, so customers have been stitching together their own local systems solutions. Architectures impose order on the system and make interconnections possible. An architectural controller has power over the standard by which the entire information package is assembled. Because of the popularity of Microsoft's Windows, for example, companies like Lotus must conform their software to its parameters to be able to compete for market share. Proprietary architectural control has broader implications for organizational structure too: architectural competition is giving rise to a new form of business organization. PMID:10126152

  5. OBSERVATIONAL QUANTIFICATION OF THE ENERGY DISSIPATED BY ALFVÉN WAVES IN A POLAR CORONAL HOLE: EVIDENCE THAT WAVES DRIVE THE FAST SOLAR WIND

    SciTech Connect

    Hahn, M.; Savin, D. W.

    2013-10-20

    We present a measurement of the energy carried and dissipated by Alfvén waves in a polar coronal hole. Alfvén waves have been proposed as the energy source that heats the corona and drives the solar wind. Previous work has shown that line widths decrease with height in coronal holes, which is a signature of wave damping, but have been unable to quantify the energy lost by the waves. This is because line widths depend on both the non-thermal velocity v{sub nt} and the ion temperature T{sub i}. We have implemented a means to separate the T{sub i} and v{sub nt} contributions using the observation that at low heights the waves are undamped and the ion temperatures do not change with height. This enables us to determine the amount of energy carried by the waves at low heights, which is proportional to v{sub nt}. We find the initial energy flux density present was 6.7 ± 0.7 × 10{sup 5} erg cm{sup –2} s{sup –1}, which is sufficient to heat the coronal hole and accelerate the solar wind during the 2007-2009 solar minimum. Additionally, we find that about 85% of this energy is dissipated below 1.5 R{sub ☉}, sufficiently low that thermal conduction can transport the energy throughout the coronal hole, heating it and driving the fast solar wind. The remaining energy is roughly consistent with what models show is needed to provide the extended heating above the sonic point for the fast solar wind. We have also studied T{sub i}, which we found to be in the range of 1-2 MK, depending on the ion species.

  6. DUAL TRIGGER OF TRANSVERSE OSCILLATIONS IN A PROMINENCE BY EUV FAST AND SLOW CORONAL WAVES: SDO/AIA AND STEREO/EUVI OBSERVATIONS

    SciTech Connect

    Gosain, S.; Foullon, C.

    2012-12-20

    We analyze flare-associated transverse oscillations in a quiescent solar prominence on 2010 September 8-9. Both the flaring active region and the prominence were located near the west limb, with a favorable configuration and viewing angle. The full-disk extreme ultraviolet (EUV) images of the Sun obtained with high spatial and temporal resolution by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory show flare-associated lateral oscillations of the prominence sheet. The STEREO-A spacecraft, 81.{sup 0}5 ahead of the Sun-Earth line, provides an on-disk view of the flare-associated coronal disturbances. We derive the temporal profile of the lateral displacement of the prominence sheet by using the image cross-correlation technique. The displacement curve was de-trended and the residual oscillatory pattern was derived. We fit these oscillations with a damped cosine function with a variable period and find that the period is increasing. The initial oscillation period (P{sub 0}) is {approx}28.2 minutes and the damping time ({tau}{sub D}) {approx} 44 minutes. We confirm the presence of fast and slow EUV wave components. Using STEREO-A observations, we derive a propagation speed of {approx}250 km s{sup -1} for the slow EUV wave by applying the time-slice technique to the running difference images. We propose that the prominence oscillations are excited by the fast EUV wave while the increase in oscillation period of the prominence is an apparent effect, related to a phase change due to the slow EUV wave acting as a secondary trigger. We discuss implications of the dual trigger effect for coronal prominence seismology and scaling law studies of damping mechanisms.

  7. Chandra Observations of Comet 2P/Encke 2003: First Detection of a Collisionally Thin, Fast Solar Wind Charge Exchange System

    NASA Technical Reports Server (NTRS)

    Lisse, C. M.; Christian, D. J.; Deneri, K.; Wolk, S. J.; Bodewits, D.; Hoekstra, R.; Combi, M. R.; Makinen, T.; Dryer, M.; Fry, C. D.; Weaver, H.

    2005-01-01

    We report the results of 15 hr of Chandra observations of comet 2P/Encke 2003 on November 24. X-ray emission from comet Encke was resolved on scales of 500-40,000 km, with unusual morphology due to the presence of a low-density, collisionally thin (to charge exchange) coma. A light curve with peak-to-peak amplitude of 20% consistent with a nucleus rotational period of 11.1 hr was found, further evidence for a collisionally thin coma. We confirm emission lines due to oxygen and neon in the 800-1000 eV range but find very unusual oxygen and carbon line ratios in the 200-700 eV range, evidence for low-density, high effective temperature solar wind composition. We compare the X-ray spectral observation results to contemporaneous measurements of the coma and solar wind made by other means and find good evidence for the dominance of a postshock bubble of expanding solar wind plasma, moving at 600 km/s with charge state composition between that of the "fast" and "slow" solar winds.

  8. INTEGRAL and XMM-Newton observations of IGR J16418-4532: evidence of accretion regime transitions in a supergiant fast X-ray transient

    NASA Astrophysics Data System (ADS)

    Drave, S. P.; Bird, A. J.; Sidoli, L.; Sguera, V.; McBride, V. A.; Hill, A. B.; Bazzano, A.; Goossens, M. E.

    2013-07-01

    We report on combined INTEGRAL and XMM-Newton observations of the supergiant fast X-ray transient (SFXT) IGR J16418-4532. The observations targeted the X-ray eclipse region of IGR J16418-4532's orbit with continuous INTEGRAL observations across ˜25 per cent of orbital phase and two quasi-simultaneous XMM-Newton observations of length 20 and 14 ks, occurring during and just after the eclipse, respectively. An enhanced INTEGRAL emission history is provided with 19 previously unreported outbursts identified in the archival 18-60 keV data set. The XMM-Newton eclipse observation showed prominent Fe emission and a flux of 2.8 × 10-13 erg cm-2 s-1 (0.5-10 keV). Through the comparison of the detected eclipse and post-eclipse flux, the supergiant mass-loss rate through the stellar wind was determined as Ṁw = 2.3-3.8 × 10-7 M⊙ yr-1. The post-eclipse XMM-Newton observation showed a dynamic flux evolution with signatures of the X-ray pulsation, a period of flaring activity, structured nH variations and the first ever detection of an X-ray intensity dip, or `off-state', in a pulsating SFXT. Consideration is given to the origin of the X-ray dip, and we conclude that the most applicable of the current theories of X-ray dip generation is that of a transition between Compton-cooling-dominated and radiative-cooling-dominated subsonic accretion regimes within the `quasi-spherical' model of wind accretion. Under this interpretation, which requires additional confirmation, the neutron star in IGR J16418-4532 possesses a magnetic field of ˜1014 G, providing tentative observational evidence of a highly magnetized neutron star in a SFXT for the first time. The implications of these results on the nature of IGR J16418-4532 itself and the wider SFXT class are discussed.

  9. Lab architecture

    NASA Astrophysics Data System (ADS)

    Crease, Robert P.

    2008-04-01

    There are few more dramatic illustrations of the vicissitudes of laboratory architecturethan the contrast between Building 20 at the Massachusetts Institute of Technology (MIT) and its replacement, the Ray and Maria Stata Center. Building 20 was built hurriedly in 1943 as temporary housing for MIT's famous Rad Lab, the site of wartime radar research, and it remained a productive laboratory space for over half a century. A decade ago it was demolished to make way for the Stata Center, an architecturally striking building designed by Frank Gehry to house MIT's computer science and artificial intelligence labs (above). But in 2004 - just two years after the Stata Center officially opened - the building was criticized for being unsuitable for research and became the subject of still ongoing lawsuits alleging design and construction failures.

  10. A Suzaku X-ray Observation of One Orbit of the Supergiant Fast X-ray Transient IGR J16479-4514

    NASA Technical Reports Server (NTRS)

    Sidoli, L.; Esposito, P.; Sguera, V.; Bodaghee, A.; Tomsick, J. A.; Pottschmidt, K.; Rodriguez, J.; Ramano, P.; Wilms, J.

    2013-01-01

    We report on a 250 ks long X-ray observation of the supergiant fast X-ray transient (SFXT) IGR J16479-4514 performed with Suzaku in 2012 February. During this observation, about 80% of the short orbital period (P(sub orb) approximates 3.32 days) was covered as continuously as possible for the first time. The source light curve displays variability of more than two orders of magnitude, starting with a very low emission state (10(exp -13) erg / sq cm/s; 1-10 keV) lasting the first 46 ks, consistent with being due to the X-ray eclipse by the supergiant companion. The transition to the uneclipsed X-ray emission is energy dependent. Outside the eclipse, the source spends most of the time at a level of 6-7X10)(exp-12) erg/sq. cm/s) punctuated by two structured faint flares with a duration of about 10 and 15 ks, respectively, reaching a peak flux of 3-4X10(exp -11) erg/sq. cm./S, separated by about 0.2 in orbital phase. Remarkably, the first faint flare occurs at a similar orbital phase of the bright flares previously observed in the system. This indicates the presence of a phase-locked large scale structure in the supergiant wind, driving a higher accretion rate onto the compact object. The average X-ray spectrum is hard and highly absorbed, with a column density, NH, of 10*exp 23)/sq cm, clearly in excess of the interstellar absorption. There is no evidence for variability of the absorbing column density, except that during the eclipse, where a less absorbed X-ray spectrum is observed. A narrow Fe K-alpha emission line at 6.4 keV is viewed along the whole orbit, with an intensity which correlates with the continuum emission above 7 keV. The scattered component visible during the X-ray eclipse allowed us to directly probe the wind density at the orbital separation, resulting in rho(sub w)=7X10(exp -14) g/cubic cm. Assuming a spherical geometry for the supergiant wind, the derived wind density translates into a ratio M(sub w)/v(sub infinity) = 7X10(exp -17) Solar M

  11. A next generation Ultra-Fast Flash Observatory (UFFO-100) for IR/optical observations of the rise phase of gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Grossan, B.; Park, I. H.; Ahmad, S.; Ahn, K. B.; Barrillon, P.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, H. S.; Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.; De La Taille, C.; Eyles, C.; Hermann, I.; Huang, M.-H. A.; Jung, A.; Jeong, S.; Kim, J. E.; Kim, M.; Kim, S.-W.; Kim, Y. W.; Lee, J.; Lim, H.; Linder, E. V.; Liu, T.-C.; Lund, N.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.; Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Suh, J. E.; Svertilov, S.; Vedenkin, N.; Wang, M.-Z.; Yashin, I.; Zhao, M. H.

    2012-09-01

    The Swift Gamma-ray Burst (GRB) observatory responds to GRB triggers with optical observations in ~ 100 s, butcannot respond faster than ~ 60 s. While some rapid-response ground-based telescopes have responded quickly, thenumber of sub-60 s detections remains small. In 2013 June, the Ultra-Fast Flash Observatory-Pathfinder is expected tobe launched on the Lomonosov spacecraft to investigate early optical GRB emission. Though possessing uniquecapability for optical rapid-response, this pathfinder mission is necessarily limited in sensitivity and event rate; here wediscuss the next generation of rapid-response space observatory instruments. We list science topics motivating ourinstruments, those that require rapid optical-IR GRB response, including: A survey of GRB rise shapes/times,measurements of optical bulk Lorentz factors, investigation of magnetic dominated (vs. non-magnetic) jet models,internal vs. external shock origin of prompt optical emission, the use of GRBs for cosmology, and dust evaporation inthe GRB environment. We also address the impacts of the characteristics of GRB observing on our instrument andobservatory design. We describe our instrument designs and choices for a next generation space observatory as a secondinstrument on a low-earth orbit spacecraft, with a 120 kg instrument mass budget. Restricted to relatively modest mass,power, and launch resources, we find that a coded mask X-ray camera with 1024 cm2 of detector area could rapidlylocate about 64 GRB triggers/year. Responding to the locations from the X-ray camera, a 30 cm aperture telescope witha beam-steering system for rapid (~ 1 s) response and a near-IR camera should detect ~ 29 GRB, given Swift GRBproperties. The additional optical camera would permit the measurement of a broadband optical-IR slope, allowingbetter characterization of the emission, and dynamic measurement of dust extinction at the source, for the first time.

  12. The FAMoUS toolbox goes to Yasur: field test of a FAst, MUltiparametric Set-up for real-time observation of explosive eruptions

    NASA Astrophysics Data System (ADS)

    Freda, C.; Taddeucci, J.; Scarlato, P.; Rao, S.; Salvaterra, C.; Gaeta, M.; Palladino, D. M.

    2012-04-01

    Explosive volcanic eruptions are intrinsically highly dynamical in space and time. For this reason, their observation in real time requires a broad range of sensors operating at high-sampling rates. Permanent networks meeting these requirements are limited to a few, intensively monitored volcanoes. Multiparametric experiments are run for limited periods at active volcanoes, but currently still require considerable logistic effort and a reliable forecast of "where" and "what" the activity will be. In contrast, the FAMoUS toolbox is a fast-deployed and flexible tool that can provide real-time observation of a broad variety of volcanic phenomena. The core of the FAMoUS toolbox includes: 1) an Optronis CamRecord 600x2 high speed camera and data logger; 2) a FLIR SC655 thermal camera; 3) two InfraCyrus microphones. All instruments are time-synchronized via a hand- or microphone-operated trigger. GPS time stamp is also available. The toolbox also includes a custom-designed power supply system, two laptops, lenses, and tripods. Total weight amounts to less than 20 kg divided into 7 items easily fitting into four, hand-luggage-sized backpacks. Deploying FAMoUS requires less than 20' whereas removing can take less than 2', if needed. The FAMoUS toolbox was first tested on Yasur volcano, Vanuatu Islands, in 10-12 July 2011, explosive activity ranging from strombolian explosions to ash venting and puffing. Visible and infrared high-speed videos were acquired at 500 and 50-200 frames per second, and 1280x1024 and 480-120x640 pixel resolution, respectively. Microphone signals were recorded at 1-20 kHz. Several volcanic processes have been thus investigated. 1) Initial jet-plume dynamics were characterized by zooming into the vents to estimate ejection velocities, gas-particle-atmosphere interactions, and mass eruption rates. 2) Ballistic pyroclast trajectories were recorded with a broader field of view, focusing on larger particles and using thermal data to discriminate

  13. The FAMoUS toolbox goes to Yasur: field test of a FAst, MUltiparametric Set-up for real-time observation of explosive eruptions

    NASA Astrophysics Data System (ADS)

    Taddeucci, J.; Freda, C.; Scarlato, P.; Rao, S.; Salvaterra, C.; Gaeta, M.; Palladino, D. M.

    2011-12-01

    Explosive volcanic eruptions are intrinsically highly dynamical in space and time. For this reason, their observation in real time requires a broad range of sensors operating at high-sampling rates. Permanent networks meeting these requirements are limited to a few, intensively monitored volcanoes. Multiparametric experiments are run for limited periods at active volcanoes, but currently still require considerable logistic effort and a reliable forecast of "where" and "what" the activity will be. In contrast, the FAMoUS toolbox is a fast-deployed and flexible tool that can provide real-time observation of a broad variety of volcanic phenomena. The core of the FAMoUS toolbox includes: 1) an Optronis CamRecord 600x2 high speed camera and data logger; 2) a FLIR SC655 thermal camera; 3) two InfraCyrus microphones. All instruments are time-synchronized via a hand- or microphone-operated trigger. GPS time stamp is also available. The toolbox also includes a custom-designed power supply system, two laptops, lenses, and tripods. Total weight amounts to less than 20 kg divided into 7 items easily fitting into four, hand-luggage-sized backpacks. Deploying FAMoUS requires less than 20' whereas removing can take less than 2', if needed. The FAMoUS toolbox was first tested on Yasur volcano, Vanuatu Islands, in 10-12 July 2011, explosive activity ranging from strombolian explosions to ash venting and puffing. Visible and infrared high-speed videos were acquired at 500 and 50-200 frames per second, and 1280x1024 and 480-120x640 pixel resolution, respectively. Microphone signals were recorded at 1-20 kHz. Several volcanic processes have been thus investigated. 1) Initial jet-plume dynamics were characterized by zooming into the vents to estimate ejection velocities, gas-particle-atmosphere interactions, and mass eruption rates. 2) Ballistic pyroclast trajectories were recorded with a broader field of view, focusing on larger particles and using thermal data to discriminate

  14. A Dual-Porosity, In Situ Crystallisation Model For Fast-Spreading Mid-Ocean Ridge Magma Chambers Based Upon Direct Observation From Hess Deep

    NASA Astrophysics Data System (ADS)

    MacLeod, C. J.; Lissenberg, C. J.

    2014-12-01

    We propose a revised magma chamber model for fast-spreading mid-ocean ridges based upon a synthesis of new data from a complete section of lower crust from the East Pacific Rise, reconstructed from samples collected from the Hess Deep rift valley during cruise JC21. Our investigation includes detailed sampling across critical transitions in the upper part of the plutonic section, including the inferred axial melt lens (AML) within the dyke-gabbro transition. We find that an overall petrological progression, from troctolite and primitive gabbro at the base up into evolved (oxide) gabbro and gabbronorite at the top of the lower crustal section, is mirrored by a progressive upward chemical fractionation as recorded in bulk rock and mineral compositions. Crystallographic preferred orientations measured using EBSD show that the downward increase in deformation of mush required in crystal subsidence models is not observed. Together these observations are consistent only with a model in which crystallisation of upward migrating evolving melts occurs in situ in the lower crust. Over-enrichment in incompatible trace element concentrations and ratios above that possible by fractional crystallisation is ubiquitous. This implies redistribution of incompatible trace elements in the lower crust by low porosity, near-pervasive reactive porous flow of interstitial melt moving continuously upward through the mush pile. Mass balance calculations reveal a significant proportion of this trace element enriched melt is trapped at mid-crustal levels. Mineral compositions in the upper third to half of the plutonic section are too evolved to represent the crystal residues of MORB. Erupted MORB therefore must be fed from melts sourced in the deeper part of the crystal mush pile, and which must ascend rapidly without significant modification in the upper plutonics or AML. From physical models of mush processes we posit that primitive melts are transported through transient, high porosity

  15. Aerobot Autonomy Architecture

    NASA Technical Reports Server (NTRS)

    Elfes, Alberto; Hall, Jeffery L.; Kulczycki, Eric A.; Cameron, Jonathan M.; Morfopoulos, Arin C.; Clouse, Daniel S.; Montgomery, James F.; Ansar, Adnan I.; Machuzak, Richard J.

    2009-01-01

    An architecture for autonomous operation of an aerobot (i.e., a robotic blimp) to be used in scientific exploration of planets and moons in the Solar system with an atmosphere (such as Titan and Venus) is undergoing development. This architecture is also applicable to autonomous airships that could be flown in the terrestrial atmosphere for scientific exploration, military reconnaissance and surveillance, and as radio-communication relay stations in disaster areas. The architecture was conceived to satisfy requirements to perform the following functions: a) Vehicle safing, that is, ensuring the integrity of the aerobot during its entire mission, including during extended communication blackouts. b) Accurate and robust autonomous flight control during operation in diverse modes, including launch, deployment of scientific instruments, long traverses, hovering or station-keeping, and maneuvers for touch-and-go surface sampling. c) Mapping and self-localization in the absence of a global positioning system. d) Advanced recognition of hazards and targets in conjunction with tracking of, and visual servoing toward, targets, all to enable the aerobot to detect and avoid atmospheric and topographic hazards and to identify, home in on, and hover over predefined terrain features or other targets of scientific interest. The architecture is an integrated combination of systems for accurate and robust vehicle and flight trajectory control; estimation of the state of the aerobot; perception-based detection and avoidance of hazards; monitoring of the integrity and functionality ("health") of the aerobot; reflexive safing actions; multi-modal localization and mapping; autonomous planning and execution of scientific observations; and long-range planning and monitoring of the mission of the aerobot. The prototype JPL aerobot (see figure) has been tested extensively in various areas in the California Mojave desert.

  16. Interplanetary Fast Shocks and Associated Drivers Observed through the Twenty-Third Solar Minimum by WIND Over its First 2.5 Years

    NASA Technical Reports Server (NTRS)

    Mariani, F.; Berdichevsky, D.; Szabo, A.; Lepping, R. P.; Vinas, A. F.

    1999-01-01

    A list of the interplanetary (IP) shocks observed by WIND from its launch (in November 1994) to May 1997 is presented. Forty two shocks were identified. The magnetohydrodynamic nature of the shocks is investigated, and the associated shock parameters and their uncertainties are accurately computed using a practical scheme which combines two techniques. These techniques are a combination of the "pre-averaged" magnetic-coplanarity, velocity-coplanarity, and the Abraham-Schrauner-mixed methods, on the one hand, and the Vinas and Scudder [1986] technique for solving the non-linear least-squares Rankine-Hugoniot shock equations, on the other. Within acceptable limits these two techniques generally gave the same results, with some exceptions. The reasons for the exceptions are discussed. It is found that the mean strength and rate of occurrence of the shocks appears to correlated with the solar cycle. Both showed a decrease in 1996 coincident with the time of the lowest ultraviolet solar radiance, indicative of solar minimum and start of solar cycle 23, which began around June 1996. Eighteen shocks appeared to be associated with corotating interaction regions (CIRs). The distribution of their shock normals showed a mean direction peaking in the ecliptic plane and with a longitude (phi(sub n)) in that plane between perpendicular to the Parker spiral and radial from the Sun. When grouped according to the sense of the direction of propagation of the shocks the mean azimuthal (longitude) angle in GSE coordinates was approximately 194 deg for the fast-forward and approximately 20 deg for the fast-reverse shocks. Another 16 shocks were determined to be driven by solar transients, including magnetic clouds. These shocks had a broader distribution of normal directions than those of the CIR cases with a mean direction close to the Sun-Earth line. Eight shocks of unknown origin had normal orientation well off the ecliptic plane. No shock propagated with longitude phi(sub n) >= 220

  17. An Architecture to Enable Future Sensor Webs

    NASA Technical Reports Server (NTRS)

    Mandl, Dan; Caffrey, Robert; Frye, Stu; Grosvenor, Sandra; Hess, Melissa; Chien, Steve; Sherwood, Rob; Davies, Ashley; Hayden, Sandra; Sweet, Adam

    2004-01-01

    A sensor web is a coherent set of distributed 'nodes', interconnected by a communications fabric, that collectively behave as a single dynamic observing system. A 'plug and play' mission architecture enables progressive mission autonomy and rapid assembly and thereby enables sensor webs. This viewgraph presentation addresses: Target mission messaging architecture; Strategy to establish architecture; Progressive autonomy with onboard sensor web; EO-1; Adaptive array antennas (smart antennas) for satellite ground stations.

  18. Fast protein folding kinetics

    PubMed Central

    Gelman, Hannah; Gruebele, Martin

    2014-01-01

    Fast folding proteins have been a major focus of computational and experimental study because they are accessible to both techniques: they are small and fast enough to be reasonably simulated with current computational power, but have dynamics slow enough to be observed with specially developed experimental techniques. This coupled study of fast folding proteins has provided insight into the mechanisms which allow some proteins to find their native conformation well less than 1 ms and has uncovered examples of theoretically predicted phenomena such as downhill folding. The study of fast folders also informs our understanding of even “slow” folding processes: fast folders are small, relatively simple protein domains and the principles that govern their folding also govern the folding of more complex systems. This review summarizes the major theoretical and experimental techniques used to study fast folding proteins and provides an overview of the major findings of fast folding research. Finally, we examine the themes that have emerged from studying fast folders and briefly summarize their application to protein folding in general as well as some work that is left to do. PMID:24641816

  19. Fasting and cognitive function.

    PubMed

    Pollitt, E; Lewis, N L; Garza, C; Shulman, R J

    The effects of short-term fasting (skipping breakfast) on the problem-solving performance of 9 to 11 yr old children were studied under the controlled conditions of a metabolic ward. The behavioral test battery included an assessment of IQ, the Matching Familiar Figure Test and Hagen Central Incidental Test. Glucose and insulin levels were measured in blood. All assessments were made under fasting and non-fasting conditions. Skipping breakfast was found to have adverse effects on the children's late morning problem-solving performance. These findings support observations that the timing and nutrient composition of meals have acute and demonstrable effects on behavior. PMID:6764933

  20. Region-referenced phase unwrapping architecture for digital holographic microscopy.

    PubMed

    Hwang, Wen-Jyi; Chen, Huan-Yuan; Cheng, Chau-Jern

    2015-01-01

    This work presents a novel hardware phase-unwrapping architecture for digital holographic microscopy. The architecture is based on an iterative region-referenced algorithm because of its simplicity and effectiveness for phase unwrapping. The architecture therefore consumes fewer hardware resources for very large-scale integration implementation. In addition, a novel data reuse scheme is adopted for reducing the memory bandwidth required by the architecture. The architecture can then have fast computation speed for the iterative operations. The architecture has been implemented by field programmable gate array. It acts as a hardware accelerator in an embedded system developed by a network-on-chip platform for performance measurement. The superiorities of the proposed architecture have been confirmed by the experiments. PMID:25967024

  1. Discovery with FAST

    NASA Astrophysics Data System (ADS)

    Wilkinson, P.

    2016-02-01

    FAST offers "transformational" performance well-suited to finding new phenomena - one of which might be polarised spectral transients. But discoveries will only be made if "the system" provides its users with the necessary opportunities. In addition to designing in as much observational flexibility as possible, FAST should be operated with a philosophy which maximises its "human bandwidth". This band includes the astronomers of tomorrow - many of whom not have yet started school or even been born.

  2. Evolution of genome architecture.

    PubMed

    Koonin, Eugene V

    2009-02-01

    Charles Darwin believed that all traits of organisms have been honed to near perfection by natural selection. The empirical basis underlying Darwin's conclusions consisted of numerous observations made by him and other naturalists on the exquisite adaptations of animals and plants to their natural habitats and on the impressive results of artificial selection. Darwin fully appreciated the importance of heredity but was unaware of the nature and, in fact, the very existence of genomes. A century and a half after the publication of the "Origin", we have the opportunity to draw conclusions from the comparisons of hundreds of genome sequences from all walks of life. These comparisons suggest that the dominant mode of genome evolution is quite different from that of the phenotypic evolution. The genomes of vertebrates, those purported paragons of biological perfection, turned out to be veritable junkyards of selfish genetic elements where only a small fraction of the genetic material is dedicated to encoding biologically relevant information. In sharp contrast, genomes of microbes and viruses are incomparably more compact, with most of the genetic material assigned to distinct biological functions. However, even in these genomes, the specific genome organization (gene order) is poorly conserved. The results of comparative genomics lead to the conclusion that the genome architecture is not a straightforward result of continuous adaptation but rather is determined by the balance between the selection pressure, that is itself dependent on the effective population size and mutation rate, the level of recombination, and the activity of selfish elements. Although genes and, in many cases, multigene regions of genomes possess elaborate architectures that ensure regulation of expression, these arrangements are evolutionarily volatile and typically change substantially even on short evolutionary scales when gene sequences diverge minimally. Thus, the observed genome

  3. Modeling of fast neutral-beam-generated ion effects on MHD-spectroscopic observations of resistive wall mode stability in DIII-D plasmas

    SciTech Connect

    Turco, F. Hanson, J. M.; Navratil, G. A.; Turnbull, A. D.

    2015-02-15

    Experiments conducted at DIII-D investigate the role of drift kinetic damping and fast neutral beam injection (NBI)-ions in the approach to the no-wall β{sub N} limit. Modelling results show that the drift kinetic effects are significant and necessary to reproduce the measured plasma response at the ideal no-wall limit. Fast neutral-beam ions and rotation play important roles and are crucial to quantitatively match the experiment. In this paper, we report on the model validation of a series of plasmas with increasing β{sub N}, where the plasma stability is probed by active magnetohydrodynamic (MHD) spectroscopy. The response of the plasma to an externally applied field is used to probe the stable side of the resistive wall mode and obtain an indication of the proximity of the equilibrium to an instability limit. We describe the comparison between the measured plasma response and that calculated by means of the drift kinetic MARS-K code [Liu et al., Phys. Plasmas 15, 112503 (2008)], which includes the toroidal rotation, the electron and ion drift-kinetic resonances, and the presence of fast particles for the modelled plasmas. The inclusion of kinetic effects allows the code to reproduce the experimental results within ∼13% for both the amplitude and phase of the plasma response, which is a significant improvement with respect to the undamped MHD-only model. The presence of fast NBI-generated ions is necessary to obtain the low response at the highest β{sub N} levels (∼90% of the ideal no-wall limit). The toroidal rotation has an impact on the results, and a sensitivity study shows that a large variation in the predicted response is caused by the details of the rotation profiles at high β{sub N}.

  4. Shallow vent architecture during hybrid explosive-effusive activity at Cordón Caulle (Chile, 2011-12): Evidence from direct observations and pyroclast textures

    NASA Astrophysics Data System (ADS)

    Schipper, C. Ian; Castro, Jonathan M.; Tuffen, Hugh; James, Mike R.; How, Penelope

    2013-07-01

    In June 2011, an eruption of rhyolite magma began at the Puyehue-Cordón Caulle volcanic complex, southern Chile. By January 2012, explosive activity had declined from sustained pyroclastic (Plinian to sub-Plinian) fountaining to mixed gas and ash jetting punctuated by Vulcanian blasts. This explosive activity was accompanied by synchronous effusion of obsidian lava in a hybrid explosive-effusive eruption. Fortuitous climatic conditions permitted ground-based observation and video recording of transient vent dynamics as well as real-time collection of proximal juvenile ash as it sedimented from the active plume. The main eruptive vent complex and site of lava effusion were represented by two loci of Vulcanian blasts within a single tephra cone containing a pancake-shaped proto-lava dome. These blast loci each consisted of clusters of sub-vents that expressed correlated shifts in eruption intensity, indicating the presence of partially connected and/or branching zones of high permeability within the upper conduit. Pyroclast textures were examined by X-ray computed microtomography and their permeability was modelled by lattice Boltzmann simulations. The porosity (39 to 67%) and Darcian permeability (3.1 × 10- 15 m2 perpendicular to fabric to 3.8 × 10- 11 m2 parallel to fabric) of fine ash emitted during ash jetting indicate that the permeable zones comprised highly sheared, tube-like bubbly magma, and contrast with the low porosity (~ 17%) and nul permeability of bombs ejected to hundreds of metres from the vent in Vulcanian blasts. Residual H2O content of ash (0.14 wt.%) and two bombs (0.2-0.25 wt.%), determined by Karl-Fischer titration indicate degassing of this pyroclastic material to near-atmospheric pressures. Ash textures and simple degassing/vesiculation models indicate the onset of permeability by ductile processes of shear-enhanced bubble coalescence in the upper 1 to 1.5 km of the conduit. Repeated ash jetting and Vulcanian blasts indicate that such

  5. New computer architectures

    SciTech Connect

    Tiberghien, J.

    1984-01-01

    This book presents papers on supercomputers. Topics considered include decentralized computer architecture, new programming languages, data flow computers, reduction computers, parallel prefix calculations, structural and behavioral descriptions of digital systems, instruction sets, software generation, personal computing, and computer architecture education.

  6. Post and Lintel Architecture

    ERIC Educational Resources Information Center

    Daniel, Robert A.

    1973-01-01

    Author finds that children understand architectural concepts more readily when he refers to familiar non-architectural examples of them such as goal posts, chairs, tables, and playground equipment. (GB)

  7. UMTS network architecture

    NASA Astrophysics Data System (ADS)

    Katoen, J. P.; Saiedi, A.; Baccaro, I.

    1994-05-01

    This paper proposes a Functional Architecture and a corresponding Network Architecture for the Universal Mobile Telecommunication System (UMTS). Procedures like call handling, location management, and handover are considered. The architecture covers the domestic, business, and public environments. Integration with existing and forthcoming networks for fixed communications is anticipated and the Intelligent Network (IN) philosophy is applied.

  8. High performance parallel architectures

    SciTech Connect

    Anderson, R.E. )

    1989-09-01

    In this paper the author describes current high performance parallel computer architectures. A taxonomy is presented to show computer architecture from the user programmer's point-of-view. The effects of the taxonomy upon the programming model are described. Some current architectures are described with respect to the taxonomy. Finally, some predictions about future systems are presented. 5 refs., 1 fig.

  9. Fast valve

    DOEpatents

    Van Dyke, W.J.

    1992-04-07

    A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing. 4 figs.

  10. Fast valve

    DOEpatents

    Van Dyke, William J.

    1992-01-01

    A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing.

  11. Design of an integrated airframe/propulsion control system architecture

    NASA Technical Reports Server (NTRS)

    Cohen, Gerald C.; Lee, C. William; Strickland, Michael J.; Torkelson, Thomas C.

    1990-01-01

    The design of an integrated airframe/propulsion control system architecture is described. The design is based on a prevalidation methodology that uses both reliability and performance. A detailed account is given for the testing associated with a subset of the architecture and concludes with general observations of applying the methodology to the architecture.

  12. Project FAST.

    ERIC Educational Resources Information Center

    Essexville-Hampton Public Schools, MI.

    Described are components of Project FAST (Functional Analysis Systems Training) a nationally validated project to provide more effective educational and support services to learning disordered children and their regular elementary classroom teachers. The program is seen to be based on a series of modules of delivery systems ranging from mainstream…

  13. RASSP signal processing architectures

    NASA Astrophysics Data System (ADS)

    Shirley, Fred; Bassett, Bob; Letellier, J. P.

    1995-06-01

    The rapid prototyping of application specific signal processors (RASSP) program is an ARPA/tri-service effort to dramatically improve the process by which complex digital systems, particularly embedded signal processors, are specified, designed, documented, manufactured, and supported. The domain of embedded signal processing was chosen because it is important to a variety of military and commercial applications as well as for the challenge it presents in terms of complexity and performance demands. The principal effort is being performed by two major contractors, Lockheed Sanders (Nashua, NH) and Martin Marietta (Camden, NJ). For both, improvements in methodology are to be exercised and refined through the performance of individual 'Demonstration' efforts. The Lockheed Sanders' Demonstration effort is to develop an infrared search and track (IRST) processor. In addition, both contractors' results are being measured by a series of externally administered (by Lincoln Labs) six-month Benchmark programs that measure process improvement as a function of time. The first two Benchmark programs are designing and implementing a synthetic aperture radar (SAR) processor. Our demonstration team is using commercially available VME modules from Mercury Computer to assemble a multiprocessor system scalable from one to hundreds of Intel i860 microprocessors. Custom modules for the sensor interface and display driver are also being developed. This system implements either proprietary or Navy owned algorithms to perform the compute-intensive IRST function in real time in an avionics environment. Our Benchmark team is designing custom modules using commercially available processor ship sets, communication submodules, and reconfigurable logic devices. One of the modules contains multiple vector processors optimized for fast Fourier transform processing. Another module is a fiberoptic interface that accepts high-rate input data from the sensors and provides video-rate output data to a

  14. Fast vertical movement of groundwater at the borehole in volcanic confined aquifer detected from point-dilution test with multi-level observations

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Han, B.; Kim, K.; Koh, K.; Park, K.

    2007-12-01

    A point-dilution tracer test was performed at a Seokwang well field, one of the pulbic water supply system for southwestern part of Jeju island, South Korea. Seokwang well field is located at the elevation of about 180 m above mean sea level with gentle tilted surface topography to southwest direction. Based on the geological columnar section of supply well no. 3, Seokwang well field area is consisted of Basalt, tuff, clinker, and soil layer. various types of basalt such as trachy basalt, feldspar augite basalt, feldspar basalt and soil layers occurred overlapping each other and clinker zone act as permeable aquifer whereas tuff act as impermeable confining layer. 20 cubic meter's tracer solution as NaCl is injected through pipe at the depth of 170 m below top of the casing using pump and the EC breakthroughs at 18 different depths in the borehole BH3 are monitored using 5 CTD Divers and 13 series of EC sensors. The injected tracer solution transported vertically upward from the injection depth with slight downward movement of about 1 meter from the mouth of the injection pipe due to the force of inertia and gravity. The estimated vertical velocity of groundwater is 1.33 x 10-2 m/s (\\ 0.424 L/s )\\) , which was too fast to be detected by borehole logging using heat pulse type flowmeter.

  15. Observation of 1H-13C and 1H-1H proximities in a paramagnetic solid by NMR at high magnetic field under ultra-fast MAS.

    PubMed

    Li, Shenhui; Trébosc, Julien; Lafon, Olivier; Zhou, Lei; Shen, Ming; Pourpoint, Frédérique; Amoureux, Jean-Paul; Deng, Feng

    2015-02-01

    The assignment of NMR signals in paramagnetic solids is often challenging since: (i) the large paramagnetic shifts often mask the diamagnetic shifts specific to the local chemical environment, and (ii) the hyperfine interactions with unpaired electrons broaden the NMR spectra and decrease the coherence lifetime, thus reducing the efficiency of usual homo- and hetero-nuclear NMR correlation experiments. Here we show that the assignment of (1)H and (13)C signals in isotopically unmodified paramagnetic compounds with moderate hyperfine interactions can be facilitated by the use of two two-dimensional (2D) experiments: (i) (1)H-(13)C correlations with (1)H detection and (ii) (1)H-(1)H double-quantum↔single-quantum correlations. These methods are experimentally demonstrated on isotopically unmodified copper (II) complex of l-alanine at high magnetic field (18.8 T) and ultra-fast Magic Angle Spinning (MAS) frequency of 62.5 kHz. Compared to (13)C detection, we show that (1)H detection leads to a 3-fold enhancement in sensitivity for (1)H-(13)C 2D correlation experiments. By combining (1)H-(13)C and (1)H-(1)H 2D correlation experiments with the analysis of (13)C longitudinal relaxation times, we have been able to assign the (1)H and (13)C signals of each l-alanine ligand. PMID:25557861

  16. Grid Architecture 2

    SciTech Connect

    Taft, Jeffrey D.

    2016-01-01

    The report describes work done on Grid Architecture under the auspices of the Department of Electricity Office of Electricity Delivery and Reliability in 2015. As described in the first Grid Architecture report, the primary purpose of this work is to provide stakeholder insight about grid issues so as to enable superior decision making on their part. Doing this requires the creation of various work products, including oft-times complex diagrams, analyses, and explanations. This report provides architectural insights into several important grid topics and also describes work done to advance the science of Grid Architecture as well.

  17. An analysis of fast photochemistry over high northern latitudes during spring and summer using in-situ observations from ARCTAS and TOPSE

    NASA Astrophysics Data System (ADS)

    Olson, J. R.; Crawford, J. H.; Brune, W.; Mao, J.; Ren, X.; Fried, A.; Anderson, B.; Apel, E.; Beaver, M.; Blake, D.; Chen, G.; Crounse, J.; Dibb, J.; Diskin, G.; Hall, S. R.; Huey, L. G.; Knapp, D.; Richter, D.; Riemer, D.; St. Clair, J.; Ullmann, K.; Walega, J.; Weibring, P.; Weinheimer, A.; Wennberg, P.; Wisthaler, A.

    2012-08-01

    Observations of chemical constituents and meteorological quantities obtained during the two Arctic phases of the airborne campaign ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) are analyzed using an observationally constrained steady state box model. Measurements of OH and HO2 from the Penn State ATHOS instrument are compared to model predictions. Forty percent of OH measurements below 2 km are at the limit of detection during the spring phase (ARCTAS-A). While the median observed-to-calculated ratio is near one, both the scatter of observations and the model uncertainty for OH are at the magnitude of ambient values. During the summer phase (ARCTAS-B), model predictions of OH are biased low relative to observations and demonstrate a high sensitivity to the level of uncertainty in NO observations. Predictions of HO2 using observed CH2O and H2O2 as model constraints are up to a factor of two larger than observed. A temperature-dependent terminal loss rate of HO2 to aerosol recently proposed in the literature is shown to be insufficient to reconcile these differences. A comparison of ARCTAS-A to the high latitude springtime portion of the 2000 TOPSE campaign (Tropospheric Ozone Production about the Spring Equinox) shows similar meteorological and chemical environments with the exception of peroxides; observations of H2O2 during ARCTAS-A were 2.5 to 3 times larger than those during TOPSE. The cause of this difference in peroxides remains unresolved and has important implications for the Arctic HOx budget. Unconstrained model predictions for both phases indicate photochemistry alone is unable to simultaneously sustain observed levels of CH2O and H2O2; however when the model is constrained with observed CH2O, H2O2 predictions from a range of rainout parameterizations bracket its observations. A mechanism suitable to explain observed concentrations of CH2O is uncertain. Free tropospheric observations of acetaldehyde (CH3CHO

  18. An analysis of fast photochemistry over high northern latitudes during spring and summer using in-situ observations from ARCTAS and TOPSE

    NASA Astrophysics Data System (ADS)

    Olson, J. R.; Crawford, J. H.; Brune, W.; Mao, J.; Ren, X.; Fried, A.; Anderson, B.; Apel, E.; Beaver, M.; Blake, D.; Chen, G.; Crounse, J.; Dibb, J.; Diskin, G.; Hall, S. R.; Huey, L. G.; Knapp, D.; Richter, D.; Riemer, D.; St. Clair, J.; Ullmann, K.; Walega, J.; Weibring, P.; Weinheimer, A.; Wennberg, P.; Wisthaler, A.

    2012-04-01

    Observations of chemical constituents and meteorological quantities obtained during the two Arctic phases of the airborne campaign ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) are analyzed using an observationally constrained steady state box model. Measurements of OH and HO2 from the Penn State ATHOS instrument are compared to model predictions. Forty percent of OH measurements below 2 km are at the limit of detection during the spring phase (ARCTAS-A). While the median observed-to-calculated ratio is near one, both the scatter of observations and the model uncertainty for OH are at the magnitude of ambient values. During the summer phase (ARCTAS-B), model predictions of OH are biased low relative to observations and demonstrate a high sensitivity to the level of uncertainty in NO observations. Predictions of HO2 using observed CH2O and H2O2 as model constraints are up to a factor of two larger than observed. A temperature-dependent terminal loss rate of HO2 to aerosol recently proposed in the literature is shown to be insufficient to reconcile these differences. A comparison of ARCTAS-A to the high latitude springtime portion of the 2000 TOPSE campaign (Tropospheric Ozone Production about the Spring Equinox) shows similar meteorological and chemical environments with the exception of peroxides; observations of H2O2 during ARCTAS-A were 2.5 to 3 times larger than those during TOPSE. The cause of this difference in peroxides remains unresolved and has important implications for the Arctic HOx budget. Unconstrained model predictions for both phases indicate photochemistry alone is unable to simultaneously sustain observed levels of CH2O and H2O2; however when the model is constrained with observed CH2O, H2O2 predictions from a range of rainout parameterizations bracket its observations. A mechanism suitable to explain observed concentrations of CH2O is uncertain. Free tropospheric observations of acetaldehyde (CH3CHO

  19. Questioning the observation of laser-assisted ionization in fast collisions of He(2 /sup 1,3/S) with He

    SciTech Connect

    Gillen, K.T.

    1989-02-15

    In four recent papers Pradel et al. (Phys. Rev. Lett. 54, 2600 (1985); Phys. Rev. A 35, 1062 (1987)) and Monchicourt et al. (Phys. Rev. A 33, 3515 (1986); Chem. Phys. Lett. 152, 336 (1988)) give arguments claiming the observation of laser-assisted ionization of the short-lived collision complex formed during collisions of He/sup */(2 /sup 1,3/S) with He. However, estimates of the relative sizes of the assisted and unassisted ion signals observed make it very unlikely that laser-assisted ionization has been observed in those experiments. Collisional excitation to higher He/sup */ states, followed by (single-photon) ionization of the excited states, seems a more likely explanation at all energies considered.

  20. Advanced architectures for astrophysical supercomputing

    NASA Astrophysics Data System (ADS)

    Barsdell, B. R.

    2012-01-01

    This thesis explores the substantial benefits offered to astronomy research by advanced 'many-core' computing architectures, which can provide up to ten times more computing power than traditional processors. It begins by analysing the computations that are best suited to massively parallel computing and advocates a powerful, general approach to the use of many-core devices. These concepts are then put into practice to develop a fast data processing pipeline, with which new science outcomes are achieved in the field of pulsar astronomy, including the discovery of a new star. The work demonstrates how technology originally developed for the consumer market can now be used to accelerate the rate of scientific discovery.

  1. Observation of internal structure of the L-shell x-ray hypersatellites for palladium atoms multiply ionized by fast oxygen ions

    SciTech Connect

    Czarnota, M.; Banas, D.; Pajek, M.; Berset, M.; Dousse, J.-Cl.; Hoszowska, J.; Maillard, Y.-P.; Mauron, O.; Raboud, P. A.; Chmielewska, D.; Rzadkiewicz, J.; Sujkowski, Z.; Polasik, M.; Slabkowska, K.

    2010-06-15

    An observation of the internal structure of the L-shell hypersatellite x rays resulting from the one-photon decay of L{sup -2} double-vacancy states in palladium multiply ionized by oxygen ions is reported. The Pd L{sub 3}{yields}M{sub 4,5} x-ray spectrum was measured with a von Hamos high-resolution crystal spectrometer. The complex shape of the observed spectrum could be interpreted in detail using relativistic multiconfiguration Dirac-Fock calculations. The relative intensities of the measured x rays were found to be in good agreement with semiclassical approximation calculations using relativistic Dirac-Hartree-Fock wave functions.

  2. Clinical document architecture.

    PubMed

    Heitmann, Kai

    2003-01-01

    The Clinical Document Architecture (CDA), a standard developed by the Health Level Seven organisation (HL7), is an ANSI approved document architecture for exchange of clinical information using XML. A CDA document is comprised of a header with associated vocabularies and a body containing the structural clinical information. PMID:15061557

  3. Generic POCC architectures

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This document describes a generic POCC (Payload Operations Control Center) architecture based upon current POCC software practice, and several refinements to the architecture based upon object-oriented design principles and expected developments in teleoperations. The current-technology generic architecture is an abstraction based upon close analysis of the ERBS, COBE, and GRO POCC's. A series of three refinements is presented: these may be viewed as an approach to a phased transition to the recommended architecture. The third refinement constitutes the recommended architecture, which, together with associated rationales, will form the basis of the rapid synthesis environment to be developed in the remainder of this task. The document is organized into two parts. The first part describes the current generic architecture using several graphical as well as tabular representations or 'views.' The second part presents an analysis of the generic architecture in terms of object-oriented principles. On the basis of this discussion, refinements to the generic architecture are presented, again using a combination of graphical and tabular representations.

  4. The Technology of Architecture

    ERIC Educational Resources Information Center

    Reese, Susan

    2006-01-01

    This article discusses how career and technical education is helping students draw up plans for success in architectural technology. According to the College of DuPage (COD) in Glen Ellyn, Illinois, one of the two-year schools offering training in architectural technology, graduates have a number of opportunities available to them. They may work…

  5. Workflow automation architecture standard

    SciTech Connect

    Moshofsky, R.P.; Rohen, W.T.

    1994-11-14

    This document presents an architectural standard for application of workflow automation technology. The standard includes a functional architecture, process for developing an automated workflow system for a work group, functional and collateral specifications for workflow automation, and results of a proof of concept prototype.

  6. Robotic Intelligence Kernel: Architecture

    Energy Science and Technology Software Center (ESTSC)

    2009-09-16

    The INL Robotic Intelligence Kernel Architecture (RIK-A) is a multi-level architecture that supports a dynamic autonomy structure. The RIK-A is used to coalesce hardware for sensing and action as well as software components for perception, communication, behavior and world modeling into a framework that can be used to create behaviors for humans to interact with the robot.

  7. Architectural Physics: Lighting.

    ERIC Educational Resources Information Center

    Hopkinson, R. G.

    The author coordinates the many diverse branches of knowledge which have dealt with the field of lighting--physiology, psychology, engineering, physics, and architectural design. Part I, "The Elements of Architectural Physics", discusses the physiological aspects of lighting, visual performance, lighting design, calculations and measurements of…

  8. FTS2000 network architecture

    NASA Technical Reports Server (NTRS)

    Klenart, John

    1991-01-01

    The network architecture of FTS2000 is graphically depicted. A map of network A topology is provided, with interservice nodes. Next, the four basic element of the architecture is laid out. Then, the FTS2000 time line is reproduced. A list of equipment supporting FTS2000 dedicated transmissions is given. Finally, access alternatives are shown.

  9. Software Architecture Evolution

    ERIC Educational Resources Information Center

    Barnes, Jeffrey M.

    2013-01-01

    Many software systems eventually undergo changes to their basic architectural structure. Such changes may be prompted by new feature requests, new quality attribute requirements, changing technology, or other reasons. Whatever the causes, architecture evolution is commonplace in real-world software projects. Today's software architects, however,…

  10. Emerging supercomputer architectures

    SciTech Connect

    Messina, P.C.

    1987-01-01

    This paper will examine the current and near future trends for commercially available high-performance computers with architectures that differ from the mainstream ''supercomputer'' systems in use for the last few years. These emerging supercomputer architectures are just beginning to have an impact on the field of high performance computing. 7 refs., 1 tab.