Science.gov

Sample records for high-performance parallel coupler

  1. Cpl6: The New Extensible, High-Performance Parallel Coupler forthe Community Climate System Model

    SciTech Connect

    Craig, Anthony P.; Jacob, Robert L.; Kauffman, Brain; Bettge,Tom; Larson, Jay; Ong, Everest; Ding, Chris; He, Yun

    2005-03-24

    Coupled climate models are large, multiphysics applications designed to simulate the Earth's climate and predict the response of the climate to any changes in the forcing or boundary conditions. The Community Climate System Model (CCSM) is a widely used state-of-art climate model that has released several versions to the climate community over the past ten years. Like many climate models, CCSM employs a coupler, a functional unit that coordinates the exchange of data between parts of climate system such as the atmosphere and ocean. This paper describes the new coupler, cpl6, contained in the latest version of CCSM,CCSM3. Cpl6 introduces distributed-memory parallelism to the coupler, a class library for important coupler functions, and a standardized interface for component models. Cpl6 is implemented entirely in Fortran90 and uses Model Coupling Toolkit as the base for most of its classes. Cpl6 gives improved performance over previous versions and scales well on multiple platforms.

  2. 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.

  3. High Performance Parallel Computational Nanotechnology

    NASA Technical Reports Server (NTRS)

    Saini, Subhash; Craw, James M. (Technical Monitor)

    1995-01-01

    At a recent press conference, NASA Administrator Dan Goldin encouraged NASA Ames Research Center to take a lead role in promoting research and development of advanced, high-performance computer technology, including nanotechnology. Manufacturers of leading-edge microprocessors currently perform large-scale simulations in the design and verification of semiconductor devices and microprocessors. Recently, the need for this intensive simulation and modeling analysis has greatly increased, due in part to the ever-increasing complexity of these devices, as well as the lessons of experiences such as the Pentium fiasco. Simulation, modeling, testing, and validation will be even more important for designing molecular computers because of the complex specification of millions of atoms, thousands of assembly steps, as well as the simulation and modeling needed to ensure reliable, robust and efficient fabrication of the molecular devices. The software for this capacity does not exist today, but it can be extrapolated from the software currently used in molecular modeling for other applications: semi-empirical methods, ab initio methods, self-consistent field methods, Hartree-Fock methods, molecular mechanics; and simulation methods for diamondoid structures. In as much as it seems clear that the application of such methods in nanotechnology will require powerful, highly powerful systems, this talk will discuss techniques and issues for performing these types of computations on parallel systems. We will describe system design issues (memory, I/O, mass storage, operating system requirements, special user interface issues, interconnects, bandwidths, and programming languages) involved in parallel methods for scalable classical, semiclassical, quantum, molecular mechanics, and continuum models; molecular nanotechnology computer-aided designs (NanoCAD) techniques; visualization using virtual reality techniques of structural models and assembly sequences; software required to

  4. Analysis of high performance conjugate heat transfer with the OpenPALM coupler

    NASA Astrophysics Data System (ADS)

    Duchaine, Florent; Jauré, Stéphan; Poitou, Damien; Quémerais, Eric; Staffelbach, Gabriel; Morel, Thierry; Gicquel, Laurent

    2015-01-01

    In many communities such as climate science or industrial design, to solve complex coupled problems with high fidelity external coupling of legacy solvers puts a lot of pressure on the tool used for the coupling. The precision of such predictions not only largely depends on simulation resolutions and the use of huge meshes but also on high performance computing to reduce restitution times. In this context, the current work aims at studying the scalability of code coupling on high performance computing architectures for a conjugate heat transfer problem. The flow solver is a Large Eddy Simulation code that has been already ported on massively parallel architectures. The conduction solver is based on the same data structure and thus shares the flow solver scalability properties. Accurately coupling solvers on massively parallel architectures while maintaining their scalability is challenging. It requires exchanging and treating information based on two different computational grids that are partitioned differently on a different number of cores. Such transfers have to be thought to maintain code scalabilities while maintaining numerical accuracy. This raises communication and high performance computing issues: transferring data from a distributed interface to another distributed interface in a parallel way and on a very large number of processors is not straightforward and solutions are not clear. Performance tests have been carried out up to 12 288 cores on the CURIE supercomputer (TGCC/CEA). Results show a good behavior of the coupled model when increasing the number of cores thanks to the fully distributed exchange process implemented in the coupler. Advanced analyses are carried out to draw new paths for future developments for coupled simulations: i.e. optimization of the data transfer protocols through asynchronous communications or coupling-aware preprocessing of the coupled models (mesh partitioning phase).

  5. Parallel Algebraic Multigrid Methods - High Performance Preconditioners

    SciTech Connect

    Yang, U M

    2004-11-11

    The development of high performance, massively parallel computers and the increasing demands of computationally challenging applications have necessitated the development of scalable solvers and preconditioners. One of the most effective ways to achieve scalability is the use of multigrid or multilevel techniques. Algebraic multigrid (AMG) is a very efficient algorithm for solving large problems on unstructured grids. While much of it can be parallelized in a straightforward way, some components of the classical algorithm, particularly the coarsening process and some of the most efficient smoothers, are highly sequential, and require new parallel approaches. This chapter presents the basic principles of AMG and gives an overview of various parallel implementations of AMG, including descriptions of parallel coarsening schemes and smoothers, some numerical results as well as references to existing software packages.

  6. High-performance parallel input device

    NASA Astrophysics Data System (ADS)

    Daniel, R. W.; Fischer, Patrick J.; Hunter, B.

    1993-12-01

    Research into force reflecting remote manipulation has recently started to move away from common error systems towards explicit force control. In order to maximize the benefit provided by explicit force reflection the designer has to take into account the asymmetry of the bandwidths of the forward and reflecting loops. This paper reports on a high performance system designed and built at Oxford University and Harwell Laboratories and on the preliminary results achieved when performing simple force reflecting tasks. The input device is based on a modified Stewart Platform, which offers the potential of very high bandwidth force reflection, well above the normal 2 - 10 Hz range achieved with common error systems. The slave is a nuclear hardened Puma industrial robot, offering a low cost, reliable solution to remote manipulation tasks.

  7. A high-performance and cost-effective grating coupler for ultraviolet light

    NASA Astrophysics Data System (ADS)

    Zhang, Jingjing; Chen, Dingbo; Yang, Junbo; Chang, Shengli; Zhang, Hailiang; Jia, Honghui

    2015-10-01

    The ultraviolet (UV) light wavelengths, typically defined to range from10-400nm, have proven to be useful for a number of applications, such as astronomy, biology, medicine and so on. It is important for us to study on the UV and related devices. In this paper, a novel and effective grating coupler for ultraviolet light was reported, which can couple efficiently ultraviolet light from fiber to waveguide at the wavelength of 300nm. The grating coupler was based on the oxide layer of silicon surface, because ultraviolet light can be transmitted pure silicon dioxide (SiO2) with low loss. Based on Bragg condition of grating, we use FDTD method to simulate and design the grating parameters operated under TM polarization. Using our optimization design parameters (period T, incident angle θ, filling factor f and etching height h) to optimize the mode matching between the fiber and the grating region, a relatively high coupling efficiency was obtained for the fiber and waveguide interface. In our design, filling factor f=0.55, period T=280nm etching height H=110nm, incident angle θ=11° can be realized in the process of manufacture. But coupling efficiency are sensitivity to the range of period of grating and incident angle θ, which increase the difficulty of processing and experiment, the process of technology and operation need high precision. Consequently, we the coupling efficiency can be largely increased and beyond 88.5% at center wavelength of 296nm and 1dB bandwidth, in which the theory analysis and the simulation results are in good agreement and coupling efficiency is the highest for this kind of coupler reported as we known. This kind submicron-sized SiO2 waveguides that can be fabricated by mature CMOS-compatible processes are showing promise for realistic dense photonic integrated circuit (PIC) in various applications including optical communications, optical interconnects, signal processing and sensing. The gratings open the path to pure silicon dioxide

  8. High Performance Parallel Methods for Space Weather Simulations

    NASA Technical Reports Server (NTRS)

    Hunter, Paul (Technical Monitor); Gombosi, Tamas I.

    2003-01-01

    This is the final report of our NASA AISRP grant entitled 'High Performance Parallel Methods for Space Weather Simulations'. The main thrust of the proposal was to achieve significant progress towards new high-performance methods which would greatly accelerate global MHD simulations and eventually make it possible to develop first-principles based space weather simulations which run much faster than real time. We are pleased to report that with the help of this award we made major progress in this direction and developed the first parallel implicit global MHD code with adaptive mesh refinement. The main limitation of all earlier global space physics MHD codes was the explicit time stepping algorithm. Explicit time steps are limited by the Courant-Friedrichs-Lewy (CFL) condition, which essentially ensures that no information travels more than a cell size during a time step. This condition represents a non-linear penalty for highly resolved calculations, since finer grid resolution (and consequently smaller computational cells) not only results in more computational cells, but also in smaller time steps.

  9. Fundamental and HOM Coupler Design for the Superconducting Parallel-Bar Cavity

    SciTech Connect

    S.U. De Silva, J.R. Delayen,

    2011-03-01

    The superconducting parallel-bar cavity is currently being considered as a deflecting system for the Jefferson Lab 12 GeV upgrade and as a crabbing cavity for a possible LHC luminosity upgrade. Currently the designs are optimized to achieve lower surface fields within the dimensional constraints for the above applications. A detailed analysis of the fundamental input power coupler design for the parallel-bar cavity is performed considering beam loading and the effects of microphonics. For higher beam loading the damping of the HOMs is vital to reduce beam instabilities generated due to the wake fields. An analysis of threshold impedances for each application and impedances of the modes that requires damping are presented in this paper with the design of HOM couplers.

  10. Language interoperability for high-performance parallel scientific components

    SciTech Connect

    Elliot, N; Kohn, S; Smolinski, B

    1999-05-18

    With the increasing complexity and interdisciplinary nature of scientific applications, code reuse is becoming increasingly important in scientific computing. One method for facilitating code reuse is the use of components technologies, which have been used widely in industry. However, components have only recently worked their way into scientific computing. Language interoperability is an important underlying technology for these component architectures. In this paper, we present an approach to language interoperability for a high-performance parallel, component architecture being developed by the Common Component Architecture (CCA) group. Our approach is based on Interface Definition Language (IDL) techniques. We have developed a Scientific Interface Definition Language (SIDL), as well as bindings to C and Fortran. We have also developed a SIDL compiler and run-time library support for reference counting, reflection, object management, and exception handling (Babel). Results from using Babel to call a standard numerical solver library (written in C) from C and Fortran show that the cost of using Babel is minimal, where as the savings in development time and the benefits of object-oriented development support for C and Fortran far outweigh the costs.

  11. Hardware Efficient and High-Performance Networks for Parallel Computers.

    NASA Astrophysics Data System (ADS)

    Chien, Minze Vincent

    High performance interconnection networks are the key to high utilization and throughput in large-scale parallel processing systems. Since many interconnection problems in parallel processing such as concentration, permutation and broadcast problems can be cast as sorting problems, this dissertation considers the problem of sorting on a new model, called an adaptive sorting network. It presents four adaptive binary sorters the first two of which are ordinary combinational circuits while the last two exploit time-multiplexing and pipelining techniques. These sorter constructions demonstrate that any sequence of n bits can be sorted in O(log^2n) bit-level delay, using O(n) constant fanin gates. This improves the cost complexity of Batcher's binary sorters by a factor of O(log^2n) while matching their sorting time. It is further shown that any sequence of n numbers can be sorted on the same model in O(log^2n) comparator-level delay using O(nlog nloglog n) comparators. The adaptive binary sorter constructions lead to new O(n) bit-level cost concentrators and superconcentrators with O(log^2n) bit-level delay. Their employment in recently constructed permutation and generalized connectors lead to permutation and generalized connection networks with O(nlog n) bit-level cost and O(log^3n) bit-level delay. These results provide the least bit-level cost for such networks with competitive delays. Finally, the dissertation considers a key issue in the implementation of interconnection networks, namely, the pin constraint. Current VLSI technologies can house a large number of switches in a single chip, but the mere fact that one chip cannot have too many pins precludes the possibility of implementing a large connection network on a single chip. The dissertation presents techniques for partitioning connection networks into identical modules of switches in such a way that each module is contained in a single chip with an arbitrarily specified number of pins, and that the cost of

  12. A Generic Scheduling Simulator for High Performance Parallel Computers

    SciTech Connect

    Yoo, B S; Choi, G S; Jette, M A

    2001-08-01

    It is well known that efficient job scheduling plays a crucial role in achieving high system utilization in large-scale high performance computing environments. A good scheduling algorithm should schedule jobs to achieve high system utilization while satisfying various user demands in an equitable fashion. Designing such a scheduling algorithm is a non-trivial task even in a static environment. In practice, the computing environment and workload are constantly changing. There are several reasons for this. First, the computing platforms constantly evolve as the technology advances. For example, the availability of relatively powerful commodity off-the-shelf (COTS) components at steadily diminishing prices have made it feasible to construct ever larger massively parallel computers in recent years [1, 4]. Second, the workload imposed on the system also changes constantly. The rapidly increasing compute resources have provided many applications developers with the opportunity to radically alter program characteristics and take advantage of these additional resources. New developments in software technology may also trigger changes in user applications. Finally, political climate change may alter user priorities or the mission of the organization. System designers in such dynamic environments must be able to accurately forecast the effect of changes in the hardware, software, and/or policies under consideration. If the environmental changes are significant, one must also reassess scheduling algorithms. Simulation has frequently been relied upon for this analysis, because other methods such as analytical modeling or actual measurements are usually too difficult or costly. A drawback of the simulation approach, however, is that developing a simulator is a time-consuming process. Furthermore, an existing simulator cannot be easily adapted to a new environment. In this research, we attempt to develop a generic job-scheduling simulator, which facilitates the evaluation of

  13. Thermal Analysis of SRF Cavity Couplers Using Parallel Multiphysics Tool TEM3P

    SciTech Connect

    Akcelik, V; Lee, L.-Q.; Li, Z.; Ng, C.-K.; Ko, K.; Cheng, G.; Rimmer, R.; Wang, H.; /Jefferson Lab

    2009-05-20

    SLAC has developed a multi-physics simulation code TEM3P for simulating integrated effects of electromagnetic, thermal and structural loads. TEM3P shares the same software infrastructure with SLAC's parallel finite element electromagnetic codes, thus enabling all physics simulations within a single framework. The finite-element approach allows high-fidelity, high-accuracy simulations and the parallel implementation facilitates large-scale computation with fast turnaround times. In this paper, TEM3P is used to analyze thermal loading at coupler end of the JLAB SRF cavity.

  14. Thermal Analysis of SRF Cavity Couplers Using Parallel Multiphysics Tool TEM3P

    SciTech Connect

    Akcelik, V, Lee, L.-Q., Li, Z., Ng, C.-K., Ko, K.,Cheng, G., Rimmer, R., Wang, H.

    2009-05-01

    SLAC has developed a multi-physics simulation code TEM3P for simulating integrated effects of electromagnetic, thermal and structural loads. TEM3P shares the same software infrastructure with SLAC’s paralell finite element electromagnetic codes, thus enabling all physics simulations within a single framework. The finite-element approach allows high fidelity, high-accuracy simulations and the parallel implementation facilitates large-scale computation with fast turnaround times. In this paper, TEM3P is used to analyze thermal loading at coupler end of the JLAB SRF cavity.

  15. High Performance Input/Output for Parallel Computer Systems

    NASA Technical Reports Server (NTRS)

    Ligon, W. B.

    1996-01-01

    The goal of our project is to study the I/O characteristics of parallel applications used in Earth Science data processing systems such as Regional Data Centers (RDCs) or EOSDIS. Our approach is to study the runtime behavior of typical programs and the effect of key parameters of the I/O subsystem both under simulation and with direct experimentation on parallel systems. Our three year activity has focused on two items: developing a test bed that facilitates experimentation with parallel I/O, and studying representative programs from the Earth science data processing application domain. The Parallel Virtual File System (PVFS) has been developed for use on a number of platforms including the Tiger Parallel Architecture Workbench (TPAW) simulator, The Intel Paragon, a cluster of DEC Alpha workstations, and the Beowulf system (at CESDIS). PVFS provides considerable flexibility in configuring I/O in a UNIX- like environment. Access to key performance parameters facilitates experimentation. We have studied several key applications fiom levels 1,2 and 3 of the typical RDC processing scenario including instrument calibration and navigation, image classification, and numerical modeling codes. We have also considered large-scale scientific database codes used to organize image data.

  16. Development of Message Passing Routines for High Performance Parallel Computations

    NASA Technical Reports Server (NTRS)

    Summers, Edward K.

    2004-01-01

    Computational Fluid Dynamics (CFD) calculations require a great deal of computing power for completing the detailed computations involved. In an effort shorten the time it takes to complete such calculations they are implemented on a parallel computer. In the case of a parallel computer some sort of message passing structure must be used to communicate between the computers because, unlike a single machine, each computer in a parallel computing cluster does not have access to all the data or run all the parts of the total program. Thus, message passing is used to divide up the data and send instructions to each machine. The nature of my work this summer involves programming the "message passing" aspect of the parallel computer. I am working on modifying an existing program, which was written with OpenMP, and does not use a multi-machine parallel computing structure, to work with Message Passing Interface (MPI) routines. The actual code is being written in the FORTRAN 90 programming language. My goal is to write a parameterized message passing structure that could be used for a variety of individual applications and implement it on Silicon Graphics Incorporated s (SGI) IRIX operating system. With this new parameterized structure engineers would be able to speed up computations for a wide variety of purposes without having to use larger and more expensive computing equipment from another division or another NASA center.

  17. High-performance parallel interface to synchronous optical network gateway

    DOEpatents

    St. John, Wallace B.; DuBois, David H.

    1996-01-01

    A system of sending and receiving gateways interconnects high speed data interfaces, e.g., HIPPI interfaces, through fiber optic links, e.g., a SONET network. An electronic stripe distributor distributes bytes of data from a first interface at the sending gateway onto parallel fiber optics of the fiber optic link to form transmitted data. An electronic stripe collector receives the transmitted data on the parallel fiber optics and reforms the data into a format effective for input to a second interface at the receiving gateway. Preferably, an error correcting syndrome is constructed at the sending gateway and sent with a data frame so that transmission errors can be detected and corrected in a real-time basis. Since the high speed data interface operates faster than any of the fiber optic links the transmission rate must be adapted to match the available number of fiber optic links so the sending and receiving gateways monitor the availability of fiber links and adjust the data throughput accordingly. In another aspect, the receiving gateway must have sufficient available buffer capacity to accept an incoming data frame. A credit-based flow control system provides for continuously updating the sending gateway on the available buffer capacity at the receiving gateway.

  18. High-performance parallel interface to synchronous optical network gateway

    DOEpatents

    St. John, W.B.; DuBois, D.H.

    1996-12-03

    Disclosed is a system of sending and receiving gateways interconnects high speed data interfaces, e.g., HIPPI interfaces, through fiber optic links, e.g., a SONET network. An electronic stripe distributor distributes bytes of data from a first interface at the sending gateway onto parallel fiber optics of the fiber optic link to form transmitted data. An electronic stripe collector receives the transmitted data on the parallel fiber optics and reforms the data into a format effective for input to a second interface at the receiving gateway. Preferably, an error correcting syndrome is constructed at the sending gateway and sent with a data frame so that transmission errors can be detected and corrected in a real-time basis. Since the high speed data interface operates faster than any of the fiber optic links the transmission rate must be adapted to match the available number of fiber optic links so the sending and receiving gateways monitor the availability of fiber links and adjust the data throughput accordingly. In another aspect, the receiving gateway must have sufficient available buffer capacity to accept an incoming data frame. A credit-based flow control system provides for continuously updating the sending gateway on the available buffer capacity at the receiving gateway. 7 figs.

  19. A high performance parallel computing architecture for robust image features

    NASA Astrophysics Data System (ADS)

    Zhou, Renyan; Liu, Leibo; Wei, Shaojun

    2014-03-01

    A design of parallel architecture for image feature detection and description is proposed in this article. The major component of this architecture is a 2D cellular network composed of simple reprogrammable processors, enabling the Hessian Blob Detector and Haar Response Calculation, which are the most computing-intensive stage of the Speeded Up Robust Features (SURF) algorithm. Combining this 2D cellular network and dedicated hardware for SURF descriptors, this architecture achieves real-time image feature detection with minimal software in the host processor. A prototype FPGA implementation of the proposed architecture achieves 1318.9 GOPS general pixel processing @ 100 MHz clock and achieves up to 118 fps in VGA (640 × 480) image feature detection. The proposed architecture is stand-alone and scalable so it is easy to be migrated into VLSI implementation.

  20. High Performance Parallel Analysis of Coupled Problems for Aircraft Propulsion

    NASA Technical Reports Server (NTRS)

    Felippa, C. A.; Farhat, C.; Lanteri, S.; Maman, N.; Piperno, S.; Gumaste, U.

    1994-01-01

    In order to predict the dynamic response of a flexible structure in a fluid flow, the equations of motion of the structure and the fluid must be solved simultaneously. In this paper, we present several partitioned procedures for time-integrating this focus coupled problem and discuss their merits in terms of accuracy, stability, heterogeneous computing, I/O transfers, subcycling, and parallel processing. All theoretical results are derived for a one-dimensional piston model problem with a compressible flow, because the complete three-dimensional aeroelastic problem is difficult to analyze mathematically. However, the insight gained from the analysis of the coupled piston problem and the conclusions drawn from its numerical investigation are confirmed with the numerical simulation of the two-dimensional transient aeroelastic response of a flexible panel in a transonic nonlinear Euler flow regime.

  1. Parallel beam dynamics calculations on high performance computers

    NASA Astrophysics Data System (ADS)

    Ryne, Robert; Habib, Salman

    1997-02-01

    Faced with a backlog of nuclear waste and weapons plutonium, as well as an ever-increasing public concern about safety and environmental issues associated with conventional nuclear reactors, many countries are studying new, accelerator-driven technologies that hold the promise of providing safe and effective solutions to these problems. Proposed projects include accelerator transmutation of waste (ATW), accelerator-based conversion of plutonium (ABC), accelerator-driven energy production (ADEP), and accelerator production of tritium (APT). Also, next-generation spallation neutron sources based on similar technology will play a major role in materials science and biological science research. The design of accelerators for these projects will require a major advance in numerical modeling capability. For example, beam dynamics simulations with approximately 100 million particles will be needed to ensure that extremely stringent beam loss requirements (less than a nanoampere per meter) can be met. Compared with typical present-day modeling using 10,000-100,000 particles, this represents an increase of 3-4 orders of magnitude. High performance computing (HPC) platforms make it possible to perform such large scale simulations, which require 10's of GBytes of memory. They also make it possible to perform smaller simulations in a matter of hours that would require months to run on a single processor workstation. This paper will describe how HPC platforms can be used to perform the numerically intensive beam dynamics simulations required for development of these new accelerator-driven technologies.

  2. Tunable broadband light coupler based on two parallel all-fiber acousto-optic tunable filters.

    PubMed

    Zhang, Wending; Huang, Ligang; Gao, Feng; Bo, Fang; Zhang, Guoquan; Xu, Jingjun

    2013-07-15

    Based on the evanescent-field coupling between the cladding modes of two adjacent and parallel all-fiber acousto-optic tunable filters, tunable broadband light coupling with relatively uniform insertion loss of trapping spectrum was achieved. In the experiments, a wide spectral tuning range from 1490 nm to 1610 nm, covering the whole C- and L-band and parts of S-bands, was demonstrated with a wavelength tunability slope of -0.72 nm/kHz. The insertion loss of the trapping spectrum was uniform (around -5.0 dB, which can be improved with a longer evanescent-field coupling length) within the whole tuning spectral range. Such a light coupling structure would be useful in tunable broadband light coupler and broadband optical fiber add/drop multiplexer for applications in coarse wavelength division multiplexing systems. PMID:23938513

  3. The parallel I/O architecture of the high performance storage system (HPSS). Revision 1

    SciTech Connect

    Watson, R.W.; Coyne, R.A.

    1995-04-01

    Datasets up to terabyte size and petabyte capacities have created a serious imbalance between I/O and storage system performance and system functionality. One promising approach is the use of parallel data transfer techniques for client access to storage, peripheral-to-peripheral transfers, and remote file transfers. This paper describes the parallel I/O architecture and mechanisms, Parallel Transport Protocol (PTP), parallel FTP, and parallel client Application Programming Interface (API) used by the High Performance Storage System (HPSS). Parallel storage integration issues with a local parallel file system are also discussed.

  4. The parallel I/O architecture of the High Performance Storage System (HPSS)

    SciTech Connect

    Watson, R.W.; Coyne, R.A.

    1995-02-01

    Rapid improvements in computational science, processing capability, main memory sizes, data collection devices, multimedia capabilities and integration of enterprise data are producing very large datasets (10s-100s of gigabytes to terabytes). This rapid growth of data has resulted in a serious imbalance in I/O and storage system performance and functionality. One promising approach to restoring balanced I/O and storage system performance is use of parallel data transfer techniques for client access to storage, device-to-device transfers, and remote file transfers. This paper describes the parallel I/O architecture and mechanisms, Parallel Transport Protocol, parallel FIP, and parallel client Application Programming Interface (API) used by the High Performance Storage System (HPSS). Parallel storage integration issues with a local parallel file system are also discussed.

  5. Scalable High Performance Computing: Direct and Large-Eddy Turbulent Flow Simulations Using Massively Parallel Computers

    NASA Technical Reports Server (NTRS)

    Morgan, Philip E.

    2004-01-01

    This final report contains reports of research related to the tasks "Scalable High Performance Computing: Direct and Lark-Eddy Turbulent FLow Simulations Using Massively Parallel Computers" and "Devleop High-Performance Time-Domain Computational Electromagnetics Capability for RCS Prediction, Wave Propagation in Dispersive Media, and Dual-Use Applications. The discussion of Scalable High Performance Computing reports on three objectives: validate, access scalability, and apply two parallel flow solvers for three-dimensional Navier-Stokes flows; develop and validate a high-order parallel solver for Direct Numerical Simulations (DNS) and Large Eddy Simulation (LES) problems; and Investigate and develop a high-order Reynolds averaged Navier-Stokes turbulence model. The discussion of High-Performance Time-Domain Computational Electromagnetics reports on five objectives: enhancement of an electromagnetics code (CHARGE) to be able to effectively model antenna problems; utilize lessons learned in high-order/spectral solution of swirling 3D jets to apply to solving electromagnetics project; transition a high-order fluids code, FDL3DI, to be able to solve Maxwell's Equations using compact-differencing; develop and demonstrate improved radiation absorbing boundary conditions for high-order CEM; and extend high-order CEM solver to address variable material properties. The report also contains a review of work done by the systems engineer.

  6. High-performance parallel image reconstruction for the New Vacuum Solar Telescope

    NASA Astrophysics Data System (ADS)

    Li, Xue-Bao; Liu, Zhong; Wang, Feng; Jin, Zhen-Yu; Xiang, Yong-Yuan; Zheng, Yan-Fang

    2015-06-01

    Many technologies have been developed to help improve spatial resolution of observational images for ground-based solar telescopes, such as adaptive optics (AO) systems and post-processing reconstruction. As any AO system correction is only partial, it is indispensable to use post-processing reconstruction techniques. In the New Vacuum Solar Telescope (NVST), a speckle-masking method is used to achieve the diffraction-limited resolution of the telescope. Although the method is very promising, the computation is quite intensive, and the amount of data is tremendous, requiring several months to reconstruct observational data of one day on a high-end computer. To accelerate image reconstruction, we parallelize the program package on a high-performance cluster. We describe parallel implementation details for several reconstruction procedures. The code is written in the C language using the Message Passing Interface (MPI) and is optimized for parallel processing in a multiprocessor environment. We show the excellent performance of parallel implementation, and the whole data processing speed is about 71 times faster than before. Finally, we analyze the scalability of the code to find possible bottlenecks, and propose several ways to further improve the parallel performance. We conclude that the presented program is capable of executing reconstruction applications in real-time at NVST.

  7. Parallel-vector unsymmetric Eigen-Solver on high performance computers

    NASA Technical Reports Server (NTRS)

    Nguyen, Duc T.; Jiangning, Qin

    1993-01-01

    The popular QR algorithm for solving all eigenvalues of an unsymmetric matrix is reviewed. Among the basic components in the QR algorithm, it was concluded from this study, that the reduction of an unsymmetric matrix to a Hessenberg form (before applying the QR algorithm itself) can be done effectively by exploiting the vector speed and multiple processors offered by modern high-performance computers. Numerical examples of several test cases have indicated that the proposed parallel-vector algorithm for converting a given unsymmetric matrix to a Hessenberg form offers computational advantages over the existing algorithm. The time saving obtained by the proposed methods is increased as the problem size increased.

  8. Gaalop—High Performance Parallel Computing Based on Conformal Geometric Algebra

    NASA Astrophysics Data System (ADS)

    Hildenbrand, Dietmar; Pitt, Joachim; Koch, Andreas

    We present Gaalop (Geometric algebra algorithms optimizer), our tool for high-performance computing based on conformal geometric algebra. The main goal of Gaalop is to realize implementations that are most likely faster than conventional solutions. In order to achieve this goal, our focus is on parallel target platforms like FPGA (field-programmable gate arrays) or the CUDA technology from NVIDIA. We describe the concepts, current status, and future perspectives of Gaalop dealing with optimized software implementations, hardware implementations, and mixed solutions. An inverse kinematics algorithm of a humanoid robot is described as an example.

  9. High-performance parallel analysis of coupled problems for aircraft propulsion

    NASA Technical Reports Server (NTRS)

    Felippa, C. A.; Farhat, C.; Lanteri, S.; Gumaste, U.; Ronaghi, M.

    1994-01-01

    Applications are described of high-performance parallel, computation for the analysis of complete jet engines, considering its multi-discipline coupled problem. The coupled problem involves interaction of structures with gas dynamics, heat conduction and heat transfer in aircraft engines. The methodology issues addressed include: consistent discrete formulation of coupled problems with emphasis on coupling phenomena; effect of partitioning strategies, augmentation and temporal solution procedures; sensitivity of response to problem parameters; and methods for interfacing multiscale discretizations in different single fields. The computer implementation issues addressed include: parallel treatment of coupled systems; domain decomposition and mesh partitioning strategies; data representation in object-oriented form and mapping to hardware driven representation, and tradeoff studies between partitioning schemes and fully coupled treatment.

  10. Next generation Purex modeling by way of parallel processing with high performance computers

    SciTech Connect

    DeMuth, S.F.

    1993-08-01

    The Plutonium and Uranium Extraction (Purex) process is the predominant method used worldwide for solvent extraction in reprocessing spent nuclear fuels. Proper flowsheet design has a significant impact on the character of the process waste. Past Purex flowsheet modeling has been based on equilibrium conditions. It can be shown for the Purex process that optimum separation does not necessarily occur at equilibrium conditions. The next generation Purex flowsheet models should incorporate the fundamental diffusion and chemical kinetic processes required to study time-dependent behavior. Use of parallel processing with high-performance computers will permit transient multistage and multispecies design calculations based on mass transfer with simultaneous chemical reaction models. This paper presents an applicable mass transfer with chemical reaction model for the Purex system and presents a parallel processing solution methodology.

  11. High-performance FFT implementation on the BOPS ManArray parallel DSP

    NASA Astrophysics Data System (ADS)

    Pitsianis, Nikos P.; Pechanek, Gerald

    1999-11-01

    We present a high performance implementation of the FFT algorithm on the BOPS ManArray parallel DSP processor. The ManArray we consider for this application consists of an array controller and 2 to 4 fully interconnected processing elements. To expose the parallelism inherent to an FFT algorithm we use a factorization of the DFT matrix in Kronecker products, permutation and diagonal matrices. Our implementation utilizes the multiple levels of parallelism that are available on the ManArray. We use the special multiply complex instruction, that calculates the product of two complex 32-bit fixed point numbers in 2 cycles (pipelinable). Instruction level parallelism is exploited via the indirect Very Long Instruction Word (iVLIW). With an iVLIW, in the same cycle a complex number is read from memory, another complex number is written to memory, a complex multiplication starts and another finishes, two complex additions or subtractions are done and a complex number is exchanged with another processing element. Multiple local FFTs are executed in Single Instruction Multiple Data (SIMD) mode, and to avoid a costly data transposition we execute distributed FFTs in Synchronous Multiple Instructions Multiple Data (SMIMD) mode.

  12. Towards a high performance parallel library to compute fluid and flexible structures interactions

    NASA Astrophysics Data System (ADS)

    Nagar, Prateek

    LBM-IB method is useful and popular simulation technique that is adopted ubiquitously to solve Fluid-Structure interaction problems in computational fluid dynamics. These problems are known for utilizing computing resources intensively while solving mathematical equations involved in simulations. Problems involving such interactions are omnipresent, therefore, it is eminent that a faster and accurate algorithm exists for solving these equations, to reproduce a real-life model of such complex analytical problems in a shorter time period. LBM-IB being inherently parallel, proves to be an ideal candidate for developing a parallel software. This research focuses on developing a parallel software library, LBM-IB based on the algorithm proposed by [1] which is first of its kind that utilizes the high performance computing abilities of supercomputers procurable today. An initial sequential version of LBM-IB is developed that is used as a benchmark for correctness and performance evaluation of shared memory parallel versions. Two shared memory parallel versions of LBM-IB have been developed using OpenMP and Pthread library respectively. The OpenMP version is able to scale well enough, as good as 83% speedup on multicore machines for 8 cores. Based on the profiling and instrumentation done on this version, to improve the data-locality and increase the degree of parallelism, Pthread based data centric version is developed which is able to outperform the OpenMP version by 53% on manycore machines. A distributed version using the MPI interfaces on top of the cube based Pthread version has also been designed to be used by extreme scale distributed memory manycore systems.

  13. High-Performance Parallel Analysis of Coupled Problems for Aircraft Propulsion

    NASA Technical Reports Server (NTRS)

    Felippa, C. A.; Farhat, C.; Park, K. C.; Gumaste, U.; Chen, P.-S.; Lesoinne, M.; Stern, P.

    1997-01-01

    Applications are described of high-performance computing methods to the numerical simulation of complete jet engines. The methodology focuses on the partitioned analysis of the interaction of the gas flow with a flexible structure and with the fluid mesh motion driven by structural displacements. The latter is treated by a ALE technique that models the fluid mesh motion as that of a fictitious mechanical network laid along the edges of near-field elements. New partitioned analysis procedures to treat this coupled three-component problem were developed. These procedures involved delayed corrections and subcycling, and have been successfully tested on several massively parallel computers, including the iPSC-860, Paragon XP/S and the IBM SP2. The NASA-sponsored ENG10 program was used for the global steady state analysis of the whole engine. This program uses a regular FV-multiblock-grid discretization in conjunction with circumferential averaging to include effects of blade forces, loss, combustor heat addition, blockage, bleeds and convective mixing. A load-balancing preprocessor for parallel versions of ENG10 was developed as well as the capability for the first full 3D aeroelastic simulation of a multirow engine stage. This capability was tested on the IBM SP2 parallel supercomputer at NASA Ames.

  14. High-performance parallel analysis of coupled problems for aircraft propulsion

    NASA Technical Reports Server (NTRS)

    Felippa, C. A.; Farhat, C.; Chen, P.-S.; Gumaste, U.; Leoinne, M.; Stern, P.

    1995-01-01

    This research program deals with the application of high-performance computing methods to the numerical simulation of complete jet engines. The program was initiated in 1993 by applying two-dimensional parallel aeroelastic codes to the interior gas flow problem of a by-pass jet engine. The fluid mesh generation, domain decomposition and solution capabilities were successfully tested. Attention was then focused on methodology for the partitioned analysis of the interaction of the gas flow with a flexible structure and with the fluid mesh motion driven by these structural displacements. The latter is treated by an ALE technique that models the fluid mesh motion as that of a fictitious mechanical network laid along the edges of near-field fluid elements. New partitioned analysis procedures to treat this coupled 3-component problem were developed in 1994. These procedures involved delayed corrections and subcycling, and have been successfully tested on several massively parallel computers. For the global steady-state axisymmetric analysis of a complete engine we have decided to use the NASA-sponsored ENG10 program, which uses a regular FV-multiblock-grid discretization in conjunction with circumferential averaging to include effects of blade forces, loss, combustor heat addition, blockage, bleeds and convective mixing. A load-balancing preprocessor for parallel versions of ENG10 has been developed. It is planned to use the steady-state global solution provided by ENG10 as input to a localized three-dimensional FSI analysis for engine regions where aeroelastic effects may be important.

  15. High-Performance Parallel Analysis of Coupled Problems for Aircraft Propulsion

    NASA Technical Reports Server (NTRS)

    Felippa, C. A.; Farhat, C.; Park, K. C.; Gumaste, U.; Chen, P.-S.; Lesoinne, M.; Stern, P.

    1996-01-01

    This research program dealt with the application of high-performance computing methods to the numerical simulation of complete jet engines. The program was initiated in January 1993 by applying two-dimensional parallel aeroelastic codes to the interior gas flow problem of a bypass jet engine. The fluid mesh generation, domain decomposition and solution capabilities were successfully tested. Attention was then focused on methodology for the partitioned analysis of the interaction of the gas flow with a flexible structure and with the fluid mesh motion driven by these structural displacements. The latter is treated by a ALE technique that models the fluid mesh motion as that of a fictitious mechanical network laid along the edges of near-field fluid elements. New partitioned analysis procedures to treat this coupled three-component problem were developed during 1994 and 1995. These procedures involved delayed corrections and subcycling, and have been successfully tested on several massively parallel computers, including the iPSC-860, Paragon XP/S and the IBM SP2. For the global steady-state axisymmetric analysis of a complete engine we have decided to use the NASA-sponsored ENG10 program, which uses a regular FV-multiblock-grid discretization in conjunction with circumferential averaging to include effects of blade forces, loss, combustor heat addition, blockage, bleeds and convective mixing. A load-balancing preprocessor tor parallel versions of ENG10 was developed. During 1995 and 1996 we developed the capability tor the first full 3D aeroelastic simulation of a multirow engine stage. This capability was tested on the IBM SP2 parallel supercomputer at NASA Ames. Benchmark results were presented at the 1196 Computational Aeroscience meeting.

  16. High performance parallel computing of flows in complex geometries: I. Methods

    NASA Astrophysics Data System (ADS)

    Gourdain, N.; Gicquel, L.; Montagnac, M.; Vermorel, O.; Gazaix, M.; Staffelbach, G.; Garcia, M.; Boussuge, J.-F.; Poinsot, T.

    2009-01-01

    Efficient numerical tools coupled with high-performance computers, have become a key element of the design process in the fields of energy supply and transportation. However flow phenomena that occur in complex systems such as gas turbines and aircrafts are still not understood mainly because of the models that are needed. In fact, most computational fluid dynamics (CFD) predictions as found today in industry focus on a reduced or simplified version of the real system (such as a periodic sector) and are usually solved with a steady-state assumption. This paper shows how to overcome such barriers and how such a new challenge can be addressed by developing flow solvers running on high-end computing platforms, using thousands of computing cores. Parallel strategies used by modern flow solvers are discussed with particular emphases on mesh-partitioning, load balancing and communication. Two examples are used to illustrate these concepts: a multi-block structured code and an unstructured code. Parallel computing strategies used with both flow solvers are detailed and compared. This comparison indicates that mesh-partitioning and load balancing are more straightforward with unstructured grids than with multi-block structured meshes. However, the mesh-partitioning stage can be challenging for unstructured grids, mainly due to memory limitations of the newly developed massively parallel architectures. Finally, detailed investigations show that the impact of mesh-partitioning on the numerical CFD solutions, due to rounding errors and block splitting, may be of importance and should be accurately addressed before qualifying massively parallel CFD tools for a routine industrial use.

  17. High-performance parallel analysis of coupled problems for aircraft propulsion

    NASA Technical Reports Server (NTRS)

    Felippa, C. A.; Farhat, C.; Lanteri, S.; Maman, N.; Piperno, S.; Gumaste, U.

    1994-01-01

    This research program deals with the application of high-performance computing methods for the analysis of complete jet engines. We have entitled this program by applying the two dimensional parallel aeroelastic codes to the interior gas flow problem of a bypass jet engine. The fluid mesh generation, domain decomposition, and solution capabilities were successfully tested. We then focused attention on methodology for the partitioned analysis of the interaction of the gas flow with a flexible structure and with the fluid mesh motion that results from these structural displacements. This is treated by a new arbitrary Lagrangian-Eulerian (ALE) technique that models the fluid mesh motion as that of a fictitious mass-spring network. New partitioned analysis procedures to treat this coupled three-component problem are developed. These procedures involved delayed corrections and subcycling. Preliminary results on the stability, accuracy, and MPP computational efficiency are reported.

  18. Implementation of a Parallel High-Performance Visualization Technique in GRASS GIS

    SciTech Connect

    Sorokine, Alexandre

    2007-01-01

    This paper describes an extension for GRASS GIS that enables users to perform geographic visualization tasks on tiled high-resolution displays powered by the clusters of commodity personal computers. Parallel visualization systems are becoming more common in scientific computing due to the decreasing hardware costs and availability of the open source software to support such architecture. High-resolution displays allow scientists to visualize very large datasets with minimal loss of details. Such systems have a big promise especially in the field of geographic information systems because users can naturally combine several geographic scales on a single display. The paper discusses architecture, implementation and operation of pd-GRASS - a GRASS GIS extension for high-performance parallel visualization on tiled displays. pd-GRASS is specifically well suited for the very large geographic datasets such as LIDAR data or high-resolution nation-wide geographic databases. The paper also briefly touches on computational efficiency, performance and potential applications for such systems.

  19. High performance parallel computing of flows in complex geometries: II. Applications

    NASA Astrophysics Data System (ADS)

    Gourdain, N.; Gicquel, L.; Staffelbach, G.; Vermorel, O.; Duchaine, F.; Boussuge, J.-F.; Poinsot, T.

    2009-01-01

    Present regulations in terms of pollutant emissions, noise and economical constraints, require new approaches and designs in the fields of energy supply and transportation. It is now well established that the next breakthrough will come from a better understanding of unsteady flow effects and by considering the entire system and not only isolated components. However, these aspects are still not well taken into account by the numerical approaches or understood whatever the design stage considered. The main challenge is essentially due to the computational requirements inferred by such complex systems if it is to be simulated by use of supercomputers. This paper shows how new challenges can be addressed by using parallel computing platforms for distinct elements of a more complex systems as encountered in aeronautical applications. Based on numerical simulations performed with modern aerodynamic and reactive flow solvers, this work underlines the interest of high-performance computing for solving flow in complex industrial configurations such as aircrafts, combustion chambers and turbomachines. Performance indicators related to parallel computing efficiency are presented, showing that establishing fair criterions is a difficult task for complex industrial applications. Examples of numerical simulations performed in industrial systems are also described with a particular interest for the computational time and the potential design improvements obtained with high-fidelity and multi-physics computing methods. These simulations use either unsteady Reynolds-averaged Navier-Stokes methods or large eddy simulation and deal with turbulent unsteady flows, such as coupled flow phenomena (thermo-acoustic instabilities, buffet, etc). Some examples of the difficulties with grid generation and data analysis are also presented when dealing with these complex industrial applications.

  20. Multimedia OC12 parallel interface using VCSEL array to achieve high-performance cost-effective optical interconnections

    NASA Astrophysics Data System (ADS)

    Chang, Edward S.

    1996-09-01

    The multimedia communication needs high-performance, cost- effective communication techniques to transport data for the fast-growing multimedia traffic resulting from the recent deployment of World Wide Web (WWW), media-on-demand , and other multimedia applications. To transport a large volume, of multimedia data, high-performance servers are required to perform media processing and transfer. Typically, the high- performance multimedia server is a massively parallel processor with a high number of I/O ports, high storage capacity, fast signal processing, and excellent cost- performance. The parallel I/O ports of the server are connected to multiple clients through a network switch which uses parallel links in both switch-to-server and switch-to- client connections. In addition to media processing and storage, media communication is also a major function of the multimedia system. Without a high-performance communication network, a high-performance server can not deliver its full capacity of service to clients. Fortunately, there are many advanced communication technologies developed for networking, which can be adopted by the multimedia communication to economically deliver the full capacity of a high-performance multimedia service to clients. The VCSEL array technology has been developed for gigabit-rate parallel optical interconnections because of its high bandwidth, small-size, and easy-fabrication advantages. Several firms are developing multifiber, low-skew, low-cost ribbon cables to transfer signals form a VCSEL array. The OC12 SONET data-rate is widely used by high-performance multimedia communications for its high-data-rate and cost- effectiveness. Therefore, the OC12 VCSEL parallel optical interconnection is the ideal technology to meet the high- performance low-cost requirements for delivering affordable multimedia services to mass users. This paper describes a multimedia OC12 parallel optical interconnection using a VCSEL array transceiver, a multifiber

  1. Scalable Unix commands for parallel processors : a high-performance implementation.

    SciTech Connect

    Ong, E.; Lusk, E.; Gropp, W.

    2001-06-22

    We describe a family of MPI applications we call the Parallel Unix Commands. These commands are natural parallel versions of common Unix user commands such as ls, ps, and find, together with a few similar commands particular to the parallel environment. We describe the design and implementation of these programs and present some performance results on a 256-node Linux cluster. The Parallel Unix Commands are open source and freely available.

  2. Scalable parallel programming for high performance seismic simulation on petascale heterogeneous supercomputers

    NASA Astrophysics Data System (ADS)

    Zhou, Jun

    The 1994 Northridge earthquake in Los Angeles, California, killed 57 people, injured over 8,700 and caused an estimated $20 billion in damage. Petascale simulations are needed in California and elsewhere to provide society with a better understanding of the rupture and wave dynamics of the largest earthquakes at shaking frequencies required to engineer safe structures. As the heterogeneous supercomputing infrastructures are becoming more common, numerical developments in earthquake system research are particularly challenged by the dependence on the accelerator elements to enable "the Big One" simulations with higher frequency and finer resolution. Reducing time to solution and power consumption are two primary focus area today for the enabling technology of fault rupture dynamics and seismic wave propagation in realistic 3D models of the crust's heterogeneous structure. This dissertation presents scalable parallel programming techniques for high performance seismic simulation running on petascale heterogeneous supercomputers. A real world earthquake simulation code, AWP-ODC, one of the most advanced earthquake codes to date, was chosen as the base code in this research, and the testbed is based on Titan at Oak Ridge National Laboraratory, the world's largest hetergeneous supercomputer. The research work is primarily related to architecture study, computation performance tuning and software system scalability. An earthquake simulation workflow has also been developed to support the efficient production sets of simulations. The highlights of the technical development are an aggressive performance optimization focusing on data locality and a notable data communication model that hides the data communication latency. This development results in the optimal computation efficiency and throughput for the 13-point stencil code on heterogeneous systems, which can be extended to general high-order stencil codes. Started from scratch, the hybrid CPU/GPU version of AWP

  3. The Design and Implementation of hypre, a Library of Parallel High Performance Preconditioners

    SciTech Connect

    Falgout, R D; Jones, J E; Yang, U M

    2004-07-17

    The increasing demands of computationally challenging applications and the advance of larger more powerful computers with more complicated architectures have necessitated the development of new solvers and preconditioners. Since the implementation of these methods is quite complex, the use of high performance libraries with the newest efficient solvers and preconditioners becomes more important for promulgating their use into applications with relative ease. The hypre library [14, 17] has been designed with the primary goal of providing users with advanced scalable parallel preconditioners. Issues of robustness, ease of use, flexibility and interoperability have also been important. It can be used both as a solver package and as a framework for algorithm development. Its object model is more general and flexible than most current generation solver libraries [9]. hypre also provides several of the most commonly used solvers, such as conjugate gradient for symmetric systems or GMRES for nonsymmetric systems to be used in conjunction with the preconditioners. Design innovations have been made to enable access to the library in the way that applications users naturally think about their problems. For example, application developers that use structured grids, typically think of their problems in terms of stencils and grids. hypre's users do not have to learn complicated sparse matrix structures; instead hypre does the work of building these data structures through various conceptual interfaces. The conceptual interfaces currently implemented include stencil-based structured and semi-structured interfaces, a finite-element based unstructured interface, and a traditional linear-algebra based interface. The primary focus of this paper is on the design and implementation of the conceptual interfaces in hypre. The paper is organized as follows. The first two sections are of general interest.We begin in Section 2 with an introductory discussion of conceptual interfaces and

  4. Parallel Processing of Numerical Tsunami Simulations on a High Performance Cluster based on the GDAL Library

    NASA Astrophysics Data System (ADS)

    Schroeder, Matthias; Jankowski, Cedric; Hammitzsch, Martin; Wächter, Joachim

    2014-05-01

    Thousands of numerical tsunami simulations allow the computation of inundation and run-up along the coast for vulnerable areas over the time. A so-called Matching Scenario Database (MSDB) [1] contains this large number of simulations in text file format. In order to visualize these wave propagations the scenarios have to be reprocessed automatically. In the TRIDEC project funded by the seventh Framework Programme of the European Union a Virtual Scenario Database (VSDB) and a Matching Scenario Database (MSDB) were established amongst others by the working group of the University of Bologna (UniBo) [1]. One part of TRIDEC was the developing of a new generation of a Decision Support System (DSS) for tsunami Early Warning Systems (TEWS) [2]. A working group of the GFZ German Research Centre for Geosciences was responsible for developing the Command and Control User Interface (CCUI) as central software application which support operator activities, incident management and message disseminations. For the integration and visualization in the CCUI, the numerical tsunami simulations from MSDB must be converted into the shapefiles format. The usage of shapefiles enables a much easier integration into standard Geographic Information Systems (GIS). Since also the CCUI is based on two widely used open source products (GeoTools library and uDig), whereby the integration of shapefiles is provided by these libraries a priori. In this case, for an example area around the Western Iberian margin several thousand tsunami variations were processed. Due to the mass of data only a program-controlled process was conceivable. In order to optimize the computing efforts and operating time the use of an existing GFZ High Performance Computing Cluster (HPC) had been chosen. Thus, a geospatial software was sought after that is capable for parallel processing. The FOSS tool Geospatial Data Abstraction Library (GDAL/OGR) was used to match the coordinates with the wave heights and generates the

  5. Geometrically nonlinear design sensitivity analysis on parallel-vector high-performance computers

    NASA Technical Reports Server (NTRS)

    Baddourah, Majdi A.; Nguyen, Duc T.

    1993-01-01

    Parallel-vector solution strategies for generation and assembly of element matrices, solution of the resulted system of linear equations, calculations of the unbalanced loads, displacements, stresses, and design sensitivity analysis (DSA) are all incorporated into the Newton Raphson (NR) procedure for nonlinear finite element analysis and DSA. Numerical results are included to show the performance of the proposed method for structural analysis and DSA in a parallel-vector computer environment.

  6. GROMACS: High performance molecular simulations through multi-level parallelism from laptops to supercomputers

    NASA Astrophysics Data System (ADS)

    Abraham, Mark James; Murtola, Teemu; Schulz, Roland; Páll, Szilárd; Smith, Jeremy C.; Hess, Berk; Lindahl, Erik

    2015-09-01

    GROMACS is one of the most widely used open-source and free software codes in chemistry, used primarily for dynamical simulations of biomolecules. It provides a rich set of calculation types, preparation and analysis tools. Several advanced techniques for free-energy calculations are supported. In version 5, it reaches new performance heights, through several new and enhanced parallelization algorithms. These work on every level; SIMD registers inside cores, multithreading, heterogeneous CPU-GPU acceleration, state-of-the-art 3D domain decomposition, and ensemble-level parallelization through built-in replica exchange and the separate Copernicus framework. The latest best-in-class compressed trajectory storage format is supported.

  7. High Performance Parallel Processing Project: Industrial computing initiative. Progress reports for fiscal year 1995

    SciTech Connect

    Koniges, A.

    1996-02-09

    This project is a package of 11 individual CRADA`s plus hardware. This innovative project established a three-year multi-party collaboration that is significantly accelerating the availability of commercial massively parallel processing computing software technology to U.S. government, academic, and industrial end-users. This report contains individual presentations from nine principal investigators along with overall program information.

  8. High-Performance Computation of Distributed-Memory Parallel 3D Voronoi and Delaunay Tessellation

    SciTech Connect

    Peterka, Tom; Morozov, Dmitriy; Phillips, Carolyn

    2014-11-14

    Computing a Voronoi or Delaunay tessellation from a set of points is a core part of the analysis of many simulated and measured datasets: N-body simulations, molecular dynamics codes, and LIDAR point clouds are just a few examples. Such computational geometry methods are common in data analysis and visualization; but as the scale of simulations and observations surpasses billions of particles, the existing serial and shared-memory algorithms no longer suffice. A distributed-memory scalable parallel algorithm is the only feasible approach. The primary contribution of this paper is a new parallel Delaunay and Voronoi tessellation algorithm that automatically determines which neighbor points need to be exchanged among the subdomains of a spatial decomposition. Other contributions include periodic and wall boundary conditions, comparison of our method using two popular serial libraries, and application to numerous science datasets.

  9. HIVE-Hexagon: High-Performance, Parallelized Sequence Alignment for Next-Generation Sequencing Data Analysis

    PubMed Central

    Santana-Quintero, Luis; Dingerdissen, Hayley; Thierry-Mieg, Jean; Mazumder, Raja; Simonyan, Vahan

    2014-01-01

    Due to the size of Next-Generation Sequencing data, the computational challenge of sequence alignment has been vast. Inexact alignments can take up to 90% of total CPU time in bioinformatics pipelines. High-performance Integrated Virtual Environment (HIVE), a cloud-based environment optimized for storage and analysis of extra-large data, presents an algorithmic solution: the HIVE-hexagon DNA sequence aligner. HIVE-hexagon implements novel approaches to exploit both characteristics of sequence space and CPU, RAM and Input/Output (I/O) architecture to quickly compute accurate alignments. Key components of HIVE-hexagon include non-redundification and sorting of sequences; floating diagonals of linearized dynamic programming matrices; and consideration of cross-similarity to minimize computations. Availability https://hive.biochemistry.gwu.edu/hive/ PMID:24918764

  10. The Parallel Bayesian Toolbox for High-performance Bayesian Filtering in Metrology

    NASA Astrophysics Data System (ADS)

    Garcia, E.; Hausotte, T.

    2013-12-01

    The Bayesian theorem is the most used instrument for stochastic inferencing in nonlinear dynamic systems and also the fundament of measurement uncertainty evaluation in the GUM. Many powerful algorithms have been derived and applied to numerous problems. The most widely used algorithms are the broad family of Kalman filters (KFs), the grid-based filters and the more recent particle filters (PFs). Over the last 15 years, especially PFs are increasingly the subject of researches and engineering applications such as dynamic coordinate measurements, estimating signals from noisy measurements and measurement uncertainty evaluation. This is rooted in their ability to handle arbitrary nonlinear and/or non-Gaussian systems as well as in their easy coding. They are sampling-based sequential Monte-Carlo methods, which generate a set of samples to compute an approximation of the Bayesian posterior probability density function. Thus, the PF faces the problem of high computational burden, since it converges to the true posterior when number of particles NP→∞. In order to solve these computational problems a highly parallelized C++ library, called Parallel Bayesian Toolbox (PBT), for implementing Bayes filters (BFs) was developed and released as open-source software, for the first time. In this paper the PBT is presented, analyzed and verified with respect to efficiency and performance applied to dynamic coordinate measurements of a photogrammetric coordinate measuring machine (CMM) and their online measurement uncertainty evaluation.

  11. High-performance parallel processors based on star-coupled wavelength division multiplexing optical interconnects

    DOEpatents

    Deri, Robert J.; DeGroot, Anthony J.; Haigh, Ronald E.

    2002-01-01

    As the performance of individual elements within parallel processing systems increases, increased communication capability between distributed processor and memory elements is required. There is great interest in using fiber optics to improve interconnect communication beyond that attainable using electronic technology. Several groups have considered WDM, star-coupled optical interconnects. The invention uses a fiber optic transceiver to provide low latency, high bandwidth channels for such interconnects using a robust multimode fiber technology. Instruction-level simulation is used to quantify the bandwidth, latency, and concurrency required for such interconnects to scale to 256 nodes, each operating at 1 GFLOPS performance. Performance scales have been shown to .apprxeq.100 GFLOPS for scientific application kernels using a small number of wavelengths (8 to 32), only one wavelength received per node, and achievable optoelectronic bandwidth and latency.

  12. A parallel-vector algorithm for rapid structural analysis on high-performance computers

    NASA Technical Reports Server (NTRS)

    Storaasli, Olaf O.; Nguyen, Duc T.; Agarwal, Tarun K.

    1990-01-01

    A fast, accurate Choleski method for the solution of symmetric systems of linear equations is presented. This direct method is based on a variable-band storage scheme and takes advantage of column heights to reduce the number of operations in the Choleski factorization. The method employs parallel computation in the outermost DO-loop and vector computation via the loop unrolling technique in the innermost DO-loop. The method avoids computations with zeros outside the column heights, and as an option, zeros inside the band. The close relationship between Choleski and Gauss elimination methods is examined. The minor changes required to convert the Choleski code to a Gauss code to solve non-positive-definite symmetric systems of equations are identified. The results for two large scale structural analyses performed on supercomputers, demonstrate the accuracy and speed of the method.

  13. Progress on H5Part: A Portable High Performance Parallel DataInterface for Electromagnetics Simulations

    SciTech Connect

    Adelmann, Andreas; Gsell, Achim; Oswald, Benedikt; Schietinger,Thomas; Bethel, Wes; Shalf, John; Siegerist, Cristina; Stockinger, Kurt

    2007-06-22

    Significant problems facing all experimental andcomputationalsciences arise from growing data size and complexity. Commonto allthese problems is the need to perform efficient data I/O ondiversecomputer architectures. In our scientific application, thelargestparallel particle simulations generate vast quantitiesofsix-dimensional data. Such a simulation run produces data foranaggregate data size up to several TB per run. Motived by the needtoaddress data I/O and access challenges, we have implemented H5Part,anopen source data I/O API that simplifies the use of the HierarchicalDataFormat v5 library (HDF5). HDF5 is an industry standard forhighperformance, cross-platform data storage and retrieval that runsonall contemporary architectures from large parallel supercomputerstolaptops. H5Part, which is oriented to the needs of the particlephysicsand cosmology communities, provides support for parallelstorage andretrieval of particles, structured and in the future unstructuredmeshes.In this paper, we describe recent work focusing on I/O supportforparticles and structured meshes and provide data showing performance onmodernsupercomputer architectures like the IBM POWER 5.

  14. Achieving high performance in numerical computations on RISC workstations and parallel systems

    SciTech Connect

    Goedecker, S.; Hoisie, A.

    1997-08-20

    The nominal peak speeds of both serial and parallel computers is raising rapidly. At the same time however it is becoming increasingly difficult to get out a significant fraction of this high peak speed from modern computer architectures. In this tutorial the authors give the scientists and engineers involved in numerically demanding calculations and simulations the necessary basic knowledge to write reasonably efficient programs. The basic principles are rather simple and the possible rewards large. Writing a program by taking into account optimization techniques related to the computer architecture can significantly speedup your program, often by factors of 10--100. As such, optimizing a program can for instance be a much better solution than buying a faster computer. If a few basic optimization principles are applied during program development, the additional time needed for obtaining an efficient program is practically negligible. In-depth optimization is usually only needed for a few subroutines or kernels and the effort involved is therefore also acceptable.

  15. Folded waveguide coupler

    DOEpatents

    Owens, Thomas L.

    1988-03-01

    A resonant cavity waveguide coupler for ICRH of a magnetically confined plasma. The coupler consists of a series of inter-leaved metallic vanes disposed withn an enclosure analogous to a very wide, simple rectangular waveguide that has been "folded" several times. At the mouth of the coupler, a polarizing plate is provided which has coupling apertures aligned with selected folds of the waveguide through which rf waves are launched with magnetic fields of the waves aligned in parallel with the magnetic fields confining the plasma being heated to provide coupling to the fast magnetosonic wave within the plasma in the frequency usage of from about 50-200 mHz. A shorting plate terminates the back of the cavity at a distance approximately equal to one-half the guide wavelength from the mouth of the coupler to ensure that the electric field of the waves launched through the polarizing plate apertures are small while the magnetic field is near a maximum. Power is fed into the coupler folded cavity by means of an input coaxial line feed arrangement at a point which provides an impedance match between the cavity and the coaxial input line.

  16. Parallelization of a multiregion flow and transport code using software emulated global shared memory and high performance FORTRAN

    SciTech Connect

    D`Azevedo, E.F.; Gwo, Jin-Ping

    1997-02-01

    The objectives of this research are (1) to parallelize a suite of multiregion groundwater flow and solute transport codes that use Galerkin and Lagrangian- Eulerian finite element methods, (2) to test the compatibility of a global shared memory emulation software with a High Performance FORTRAN (HPF) compiler, and (3) to obtain performance characteristics and scalability of the parallel codes. The suite of multiregion flow and transport codes, 3DMURF and 3DMURT, were parallelized using the DOLIB shared memory emulation, in conjunction with the PGI HPF compiler, to run on the Intel Paragons at the Oak Ridge National Laboratory (ORNL) and a network of workstations. The novelty of this effort is first in the use of HPF and global shared memory emulation concurrently to facilitate the conversion of a serial code to a parallel code, and secondly the shared memory library enables efficient implementation of Lagrangian particle tracking along flow characteristics. The latter allows long-time-step-size simulation with particle tracking and dynamic particle redistribution for load balancing, thereby reducing the number of time steps needed for most transient problems. The parallel codes were applied to a pumping well problem to test the efficiency of the domain decomposition and particle tracking algorithms. The full problem domain consists of over 200,000 degrees of freedom with highly nonlinear soil property functions. Relatively good scalability was obtained for a preliminary test run on the Intel Paragons at the Center for Computational Sciences (CCS), ORNL. However, due to the difficulties we encountered in the PGI HPF compiler, as of the writing of this manuscript we are able to report results from 3DMURF only.

  17. High-performance parallel solver for 3D time-dependent Schrodinger equation for large-scale nanosystems

    NASA Astrophysics Data System (ADS)

    Gainullin, I. K.; Sonkin, M. A.

    2015-03-01

    A parallelized three-dimensional (3D) time-dependent Schrodinger equation (TDSE) solver for one-electron systems is presented in this paper. The TDSE Solver is based on the finite-difference method (FDM) in Cartesian coordinates and uses a simple and explicit leap-frog numerical scheme. The simplicity of the numerical method provides very efficient parallelization and high performance of calculations using Graphics Processing Units (GPUs). For example, calculation of 106 time-steps on the 1000ṡ1000ṡ1000 numerical grid (109 points) takes only 16 hours on 16 Tesla M2090 GPUs. The TDSE Solver demonstrates scalability (parallel efficiency) close to 100% with some limitations on the problem size. The TDSE Solver is validated by calculation of energy eigenstates of the hydrogen atom (13.55 eV) and affinity level of H- ion (0.75 eV). The comparison with other TDSE solvers shows that a GPU-based TDSE Solver is 3 times faster for the problems of the same size and with the same cost of computational resources. The usage of a non-regular Cartesian grid or problem-specific non-Cartesian coordinates increases this benefit up to 10 times. The TDSE Solver was applied to the calculation of the resonant charge transfer (RCT) in nanosystems, including several related physical problems, such as electron capture during H+-H0 collision and electron tunneling between H- ion and thin metallic island film.

  18. Single Fiber Star Couplers. [optical waveguides for spacecraft communication

    NASA Technical Reports Server (NTRS)

    Asawa, C. K.

    1979-01-01

    An ion exchange process was developed and used in the fabrication of state-of-the-art planar star couplers for distribution of optical radiation between optical fibers. An 8 x 8 planar transmission star coupler was packaged for evaluation purposes with sixteen fiber connectors and sixteen pigtails. Likewise a transmission star coupler and an eight-port reflection star coupler with eight-fiber ribbons rigidly attached to these couplers, and a planar coupler with silicon guides and a parallel channel guide with pigtails were also fabricated. Optical measurements of the transmission star couplers are included with a description of the manufacturing process.

  19. Development of a high performance parallel computing platform and its use in the study of nanostructures: Clusters, sheets and tubes

    NASA Astrophysics Data System (ADS)

    Gowtham, S.

    Small clusters of gallium oxide, technologically important high temperature ceramic, together with interaction of nucleic acid bases with graphene and small-diameter carbon nanotube are focus of first principles calculations in this work. A high performance parallel computing platform is also developed to perform these calculations at Michigan Tech. First principles calculations are based on density functional theory employing either local density or gradient-corrected approximation together with plane wave and Gaussian basis sets. The bulk Ga2O3 is known to be a very good candidate for fabricating electronic devices that operate at high temperatures. To explore the properties of Ga2O3 at nanoscale, we have performed a systematic theoretical study on the small polyatomic gallium oxide clusters. The calculated results find that all lowest energy isomers of GamO n clusters are dominated by the Ga-O bonds over the metal-metal or the oxygen-oxygen bonds. Analysis of atomic charges suggest the clusters to be highly ionic similar to the case of bulk Ga2O3. In the study of sequential oxidation of these clusters starting from Ga3O, it is found that the most stable isomers display up to four different backbones of constituent atoms. Furthermore, the predicted configuration of the ground state of Ga2O is recently confirmed by the experimental results of Neumark's group. Guided by the results of calculations the study of gallium oxide clusters, performance related challenge of computational simulations, of producing high performance computers/platforms, has been addressed. Several engineering aspects were thoroughly studied during the design, development and implementation of the high performance parallel computing platform, RAMA, at Michigan Tech. In an attempt to stay true to the principles of Beowulf revolution, the RAMA cluster was extensively customized to make it easy to understand, and use - for administrators as well as end-users. Following the results of benchmark

  20. Using the Eclipse Parallel Tools Platform to Assist Earth Science Model Development and Optimization on High Performance Computers

    NASA Astrophysics Data System (ADS)

    Alameda, J. C.

    2011-12-01

    Development and optimization of computational science models, particularly on high performance computers, and with the advent of ubiquitous multicore processor systems, practically on every system, has been accomplished with basic software tools, typically, command-line based compilers, debuggers, performance tools that have not changed substantially from the days of serial and early vector computers. However, model complexity, including the complexity added by modern message passing libraries such as MPI, and the need for hybrid code models (such as openMP and MPI) to be able to take full advantage of high performance computers with an increasing core count per shared memory node, has made development and optimization of such codes an increasingly arduous task. Additional architectural developments, such as many-core processors, only complicate the situation further. In this paper, we describe how our NSF-funded project, "SI2-SSI: A Productive and Accessible Development Workbench for HPC Applications Using the Eclipse Parallel Tools Platform" (WHPC) seeks to improve the Eclipse Parallel Tools Platform, an environment designed to support scientific code development targeted at a diverse set of high performance computing systems. Our WHPC project to improve Eclipse PTP takes an application-centric view to improve PTP. We are using a set of scientific applications, each with a variety of challenges, and using PTP to drive further improvements to both the scientific application, as well as to understand shortcomings in Eclipse PTP from an application developer perspective, to drive our list of improvements we seek to make. We are also partnering with performance tool providers, to drive higher quality performance tool integration. We have partnered with the Cactus group at Louisiana State University to improve Eclipse's ability to work with computational frameworks and extremely complex build systems, as well as to develop educational materials to incorporate into

  1. DIRECTIONAL COUPLERS

    DOEpatents

    Nigg, D.J.

    1961-12-01

    A directional coupler of small size is designed. Stripline conductors of non-rectilinear configuration, and separated from each other by a thin dielectric spacer. cross each other at least at two locations at right angles, thus providing practically pure capacitive coupling which substantially eliminates undesirable inductive coupling. The conductors are sandwiched between a pair of ground planes. The coupling factor is dependent only on the thickness and dielectric constant of the dielectric spacer at the point of conductor crossover. (AEC)

  2. An Overview of High-performance Parallel Big Data transfers over multiple network channels with Transport Layer Security (TLS) and TLS plus Perfect Forward Secrecy (PFS)

    SciTech Connect

    Fang, Chin; Corttrell, R. A.

    2015-05-06

    This Technical Note provides an overview of high-performance parallel Big Data transfers with and without encryption for data in-transit over multiple network channels. It shows that with the parallel approach, it is feasible to carry out high-performance parallel "encrypted" Big Data transfers without serious impact to throughput. But other impacts, e.g. the energy-consumption part should be investigated. It also explains our rationales of using a statistics-based approach for gaining understanding from test results and for improving the system. The presentation is of high-level nature. Nevertheless, at the end we will pose some questions and identify potentially fruitful directions for future work.

  3. pWeb: A High-Performance, Parallel-Computing Framework for Web-Browser-Based Medical Simulation.

    PubMed

    Halic, Tansel; Ahn, Woojin; De, Suvranu

    2014-01-01

    This work presents a pWeb - a new language and compiler for parallelization of client-side compute intensive web applications such as surgical simulations. The recently introduced HTML5 standard has enabled creating unprecedented applications on the web. Low performance of the web browser, however, remains the bottleneck of computationally intensive applications including visualization of complex scenes, real time physical simulations and image processing compared to native ones. The new proposed language is built upon web workers for multithreaded programming in HTML5. The language provides fundamental functionalities of parallel programming languages as well as the fork/join parallel model which is not supported by web workers. The language compiler automatically generates an equivalent parallel script that complies with the HTML5 standard. A case study on realistic rendering for surgical simulations demonstrates enhanced performance with a compact set of instructions. PMID:24732497

  4. Parallel implementation of inverse adding-doubling and Monte Carlo multi-layered programs for high performance computing systems with shared and distributed memory

    NASA Astrophysics Data System (ADS)

    Chugunov, Svyatoslav; Li, Changying

    2015-09-01

    Parallel implementation of two numerical tools popular in optical studies of biological materials-Inverse Adding-Doubling (IAD) program and Monte Carlo Multi-Layered (MCML) program-was developed and tested in this study. The implementation was based on Message Passing Interface (MPI) and standard C-language. Parallel versions of IAD and MCML programs were compared to their sequential counterparts in validation and performance tests. Additionally, the portability of the programs was tested using a local high performance computing (HPC) cluster, Penguin-On-Demand HPC cluster, and Amazon EC2 cluster. Parallel IAD was tested with up to 150 parallel cores using 1223 input datasets. It demonstrated linear scalability and the speedup was proportional to the number of parallel cores (up to 150x). Parallel MCML was tested with up to 1001 parallel cores using problem sizes of 104-109 photon packets. It demonstrated classical performance curves featuring communication overhead and performance saturation point. Optimal performance curve was derived for parallel MCML as a function of problem size. Typical speedup achieved for parallel MCML (up to 326x) demonstrated linear increase with problem size. Precision of MCML results was estimated in a series of tests - problem size of 106 photon packets was found optimal for calculations of total optical response and 108 photon packets for spatially-resolved results. The presented parallel versions of MCML and IAD programs are portable on multiple computing platforms. The parallel programs could significantly speed up the simulation for scientists and be utilized to their full potential in computing systems that are readily available without additional costs.

  5. Design of high-performing hybrid meta-heuristics for unrelated parallel machine scheduling with machine eligibility and precedence constraints

    NASA Astrophysics Data System (ADS)

    Afzalirad, Mojtaba; Rezaeian, Javad

    2016-04-01

    This study involves an unrelated parallel machine scheduling problem in which sequence-dependent set-up times, different release dates, machine eligibility and precedence constraints are considered to minimize total late works. A new mixed-integer programming model is presented and two efficient hybrid meta-heuristics, genetic algorithm and ant colony optimization, combined with the acceptance strategy of the simulated annealing algorithm (Metropolis acceptance rule), are proposed to solve this problem. Manifestly, the precedence constraints greatly increase the complexity of the scheduling problem to generate feasible solutions, especially in a parallel machine environment. In this research, a new corrective algorithm is proposed to obtain the feasibility in all stages of the algorithms. The performance of the proposed algorithms is evaluated in numerical examples. The results indicate that the suggested hybrid ant colony optimization statistically outperformed the proposed hybrid genetic algorithm in solving large-size test problems.

  6. Molecular simulation workflows as parallel algorithms: the execution engine of Copernicus, a distributed high-performance computing platform.

    PubMed

    Pronk, Sander; Pouya, Iman; Lundborg, Magnus; Rotskoff, Grant; Wesén, Björn; Kasson, Peter M; Lindahl, Erik

    2015-06-01

    Computational chemistry and other simulation fields are critically dependent on computing resources, but few problems scale efficiently to the hundreds of thousands of processors available in current supercomputers-particularly for molecular dynamics. This has turned into a bottleneck as new hardware generations primarily provide more processing units rather than making individual units much faster, which simulation applications are addressing by increasingly focusing on sampling with algorithms such as free-energy perturbation, Markov state modeling, metadynamics, or milestoning. All these rely on combining results from multiple simulations into a single observation. They are potentially powerful approaches that aim to predict experimental observables directly, but this comes at the expense of added complexity in selecting sampling strategies and keeping track of dozens to thousands of simulations and their dependencies. Here, we describe how the distributed execution framework Copernicus allows the expression of such algorithms in generic workflows: dataflow programs. Because dataflow algorithms explicitly state dependencies of each constituent part, algorithms only need to be described on conceptual level, after which the execution is maximally parallel. The fully automated execution facilitates the optimization of these algorithms with adaptive sampling, where undersampled regions are automatically detected and targeted without user intervention. We show how several such algorithms can be formulated for computational chemistry problems, and how they are executed efficiently with many loosely coupled simulations using either distributed or parallel resources with Copernicus. PMID:26575558

  7. Making resonance a common case: a high-performance implementation of collective I/O on parallel file systems

    SciTech Connect

    Davis, Marion Kei; Zhang, Xuechen; Jiang, Song

    2009-01-01

    Collective I/O is a widely used technique to improve I/O performance in parallel computing. It can be implemented as a client-based or server-based scheme. The client-based implementation is more widely adopted in MPI-IO software such as ROMIO because of its independence from the storage system configuration and its greater portability. However, existing implementations of client-side collective I/O do not take into account the actual pattern offile striping over multiple I/O nodes in the storage system. This can cause a significant number of requests for non-sequential data at I/O nodes, substantially degrading I/O performance. Investigating the surprisingly high I/O throughput achieved when there is an accidental match between a particular request pattern and the data striping pattern on the I/O nodes, we reveal the resonance phenomenon as the cause. Exploiting readily available information on data striping from the metadata server in popular file systems such as PVFS2 and Lustre, we design a new collective I/O implementation technique, resonant I/O, that makes resonance a common case. Resonant I/O rearranges requests from multiple MPI processes to transform non-sequential data accesses on I/O nodes into sequential accesses, significantly improving I/O performance without compromising the independence ofa client-based implementation. We have implemented our design in ROMIO. Our experimental results show that the scheme can increase I/O throughput for some commonly used parallel I/O benchmarks such as mpi-io-test and ior-mpi-io over the existing implementation of ROMIO by up to 157%, with no scenario demonstrating significantly decreased performance.

  8. High-performance hardware implementation of a parallel database search engine for real-time peptide mass fingerprinting

    PubMed Central

    Bogdán, István A.; Rivers, Jenny; Beynon, Robert J.; Coca, Daniel

    2008-01-01

    Motivation: Peptide mass fingerprinting (PMF) is a method for protein identification in which a protein is fragmented by a defined cleavage protocol (usually proteolysis with trypsin), and the masses of these products constitute a ‘fingerprint’ that can be searched against theoretical fingerprints of all known proteins. In the first stage of PMF, the raw mass spectrometric data are processed to generate a peptide mass list. In the second stage this protein fingerprint is used to search a database of known proteins for the best protein match. Although current software solutions can typically deliver a match in a relatively short time, a system that can find a match in real time could change the way in which PMF is deployed and presented. In a paper published earlier we presented a hardware design of a raw mass spectra processor that, when implemented in Field Programmable Gate Array (FPGA) hardware, achieves almost 170-fold speed gain relative to a conventional software implementation running on a dual processor server. In this article we present a complementary hardware realization of a parallel database search engine that, when running on a Xilinx Virtex 2 FPGA at 100 MHz, delivers 1800-fold speed-up compared with an equivalent C software routine, running on a 3.06 GHz Xeon workstation. The inherent scalability of the design means that processing speed can be multiplied by deploying the design on multiple FPGAs. The database search processor and the mass spectra processor, running on a reconfigurable computing platform, provide a complete real-time PMF protein identification solution. Contact: d.coca@sheffield.ac.uk PMID:18453553

  9. Benchmarking and parallel scalability of MANCINTAP, a Parallel High-Performance Tool For Neutron Activation Analysis in Complex 4D Scenarios

    NASA Astrophysics Data System (ADS)

    Firpo, G.; Frambati, S.; Frignani, M.; Gerra, G.

    2014-06-01

    MANCINTAP is a parallel computational tool developed by Ansaldo Nucleare to perform 4D neutron transport, activation and time-resolved dose-rate calculations in very complex geometries for CPU-intensive fission and fusion applications. MANCINTAP creates an automated link between the 3D radiation transport code MCNP5—which is used to evaluate both the neutron fluxes for activation calculations and the resulting secondary gamma dose rates—and the zero-dimensional activation code Anita2000 by handling crucial processes such as data exchange, determination of material mixtures and generation of cumulative probability distributions. A brief description of the computational tool is given here, with particular emphasis on the key technical choices underlying the project. Benchmarking of MANCINTAP has been performed in three steps: (i) against a very simplified model, where an analytical solution is available for comparison; (ii) against the well-established deterministic transport and activation code ATTILA and (iii) against experimental data obtained at the Frascati Neutron Generator (FNG) facility. An analysis of MANCINTAP scalability performances is proposed to demonstrate the robustness of its parallel structure, tailored for HPC applications, which makes it—to the best of our knowledge—a novel tool.

  10. Parallel microscope-based fluorescence, absorbance and time-of-flight mass spectrometry detection for high performance liquid chromatography and determination of glucosamine in urine.

    PubMed

    Xiong, Bo; Wang, Ling-Ling; Li, Qiong; Nie, Yu-Ting; Cheng, Shuang-Shuang; Zhang, Hui; Sun, Ren-Qiang; Wang, Yu-Jiao; Zhou, Hong-Bin

    2015-11-01

    A parallel microscope-based laser-induced fluorescence (LIF), ultraviolet-visible absorbance (UV) and time-of-flight mass spectrometry (TOF-MS) detection for high performance liquid chromatography (HPLC) was achieved and used to determine glucosamine in urines. First, a reliable and convenient LIF detection was developed based on an inverted microscope and corresponding modulations. Parallel HPLC-LIF/UV/TOF-MS detection was developed by the combination of preceding Microscope-based LIF detection and HPLC coupled with UV and TOF-MS. The proposed setup, due to its parallel scheme, was free of the influence from photo bleaching in LIF detection. Rhodamine B, glutamic acid and glucosamine have been determined to evaluate its performance. Moreover, the proposed strategy was used to determine the glucosamine in urines, and subsequent results suggested that glucosamine, which was widely used in the prevention of the bone arthritis, was metabolized to urines within 4h. Furthermore, its concentration in urines decreased to 5.4mM at 12h. Efficient glucosamine detection was achieved based on a sensitive quantification (LIF), a universal detection (UV) and structural characterizations (TOF-MS). This application indicated that the proposed strategy was sensitive, universal and versatile, and it was capable of improved analysis, especially for analytes with low concentrations in complex samples, compared with conventional HPLC-UV/TOF-MS. PMID:26452822

  11. Transverse emittance dilution due to coupler kicks in linear accelerators

    NASA Astrophysics Data System (ADS)

    Buckley, Brandon; Hoffstaetter, Georg H.

    2007-11-01

    One of the main concerns in the design of low emittance linear accelerators (linacs) is the preservation of beam emittance. Here we discuss one possible source of emittance dilution, the coupler kick, due to transverse electromagnetic fields in the accelerating cavities of the linac caused by the power coupler geometry. In addition to emittance growth, the coupler kick also produces orbit distortions. It is common wisdom that emittance growth from coupler kicks can be strongly reduced by using two couplers per cavity mounted opposite each other or by having the couplers of successive cavities alternate from above to below the beam pipe so as to cancel each individual kick. While this is correct, including two couplers per cavity or alternating the coupler location requires large technical changes and increased cost for superconducting cryomodules where cryogenic pipes are arranged parallel to a string of several cavities. We therefore analyze consequences of alternate coupler placements. We show here that alternating the coupler location from above to below compensates the emittance growth as well as the orbit distortions. For sufficiently large Q values, alternating the coupler location from before to after the cavity leads to a cancellation of the orbit distortion but not of the emittance growth, whereas alternating the coupler location from before and above to behind and below the cavity cancels the emittance growth but not the orbit distortion. We show that cancellations hold for sufficiently large Q values. These compensations hold even when each cavity is individually detuned, e.g., by microphonics. Another effective method for reducing coupler kicks that is studied is the optimization of the phase of the coupler kick so as to minimize the effects on emittance from each coupler. This technique is independent of the coupler geometry but relies on operating on crest. A final technique studied is symmetrization of the cavity geometry in the coupler region with

  12. High Performance FORTRAN

    NASA Technical Reports Server (NTRS)

    Mehrotra, Piyush

    1994-01-01

    High performance FORTRAN is a set of extensions for FORTRAN 90 designed to allow specification of data parallel algorithms. The programmer annotates the program with distribution directives to specify the desired layout of data. The underlying programming model provides a global name space and a single thread of control. Explicitly parallel constructs allow the expression of fairly controlled forms of parallelism in particular data parallelism. Thus the code is specified in a high level portable manner with no explicit tasking or communication statements. The goal is to allow architecture specific compilers to generate efficient code for a wide variety of architectures including SIMD, MIMD shared and distributed memory machines.

  13. Multimode Directional Coupler

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N. (Inventor); Wintucky, Edwin G. (Inventor)

    2016-01-01

    A multimode directional coupler is provided. In some embodiments, the multimode directional coupler is configured to receive a primary signal and a secondary signal at a first port of a primary waveguide. The primary signal is configured to propagate through the primary waveguide and be outputted at a second port of the primary waveguide. The multimode directional coupler also includes a secondary waveguide configured to couple the secondary signal from the primary waveguide with no coupling of the primary signal into the secondary waveguide. The secondary signal is configured to propagate through the secondary waveguide and be outputted from a port of the secondary waveguide.

  14. Plastic star coupler

    NASA Astrophysics Data System (ADS)

    Yuuki, Hayato; Ito, Takeharu; Sugimoto, Tetsuo

    1991-12-01

    We applied an ultrasonic welding method for the bonding of plastic fibers, and obtained many types of optical star couplers for optical communication systems. It enables the manufacturing of optical components with low loss without damaging the clad layer except for the welding surface. Therefore, they have some merits, such as low loss, small size, light weight, and low cost. The 4-ports (2 X 2) star coupler of 1000 micrometers diam APF has 0.7 dB excess loss at most, and the welding length is 20 mm.

  15. Integrated optical XY coupler

    DOEpatents

    Vawter, G.A.; Hadley, G.R.

    1997-05-06

    An integrated optical XY coupler having two converging input waveguide arms meeting in a central section and a central output waveguide arm and two diverging flanking output waveguide arms emanating from the central section. In-phase light from the input arms constructively interferes in the central section to produce a single mode output in the central output arm with the rest of the light being collected in the flanking output arms. Crosstalk between devices on a substrate is minimized by this collection of the out-of-phase light by the flanking output arms of the XY coupler. 9 figs.

  16. Integrated optical XY coupler

    DOEpatents

    Vawter, G. Allen; Hadley, G. Ronald

    1997-01-01

    An integrated optical XY coupler having two converging input waveguide arms meeting in a central section and a central output waveguide arm and two diverging flanking output waveguide arms emanating from the central section. In-phase light from the input arms constructively interfers in the central section to produce a single mode output in the central output arm with the rest of the light being collected in the flanking output arms. Crosstalk between devices on a substrate is minimized by this collection of the out-of-phase light by the flanking output arms of the XY coupler.

  17. Element of an inductive coupler

    DOEpatents

    Hall, David R.; Fox, Joe

    2006-08-15

    An element for an inductive coupler in a downhole component comprises magnetically conductive material, which is disposed in a recess in annular housing. The magnetically conductive material forms a generally circular trough. The circular trough comprises an outer generally U-shaped surface, an inner generally U-shaped surface, and two generally planar surfaces joining the inner and outer surfaces. The element further comprises pressure relief grooves in at least one of the surfaces of the circular trough. The pressure relief grooves may be scored lines. Preferably the pressure relief grooves are parallel to the magnetic field generated by the magnetically conductive material. The magnetically conductive material is selected from the group consisting of soft iron, ferrite, a nickel iron alloy, a silicon iron alloy, a cobalt iron alloy, and a mu-metal. Preferably, the annular housing is a metal ring.

  18. High Performance Fortran: An overview

    SciTech Connect

    Zosel, M.E.

    1992-12-23

    The purpose of this paper is to give an overview of the work of the High Performance Fortran Forum (HPFF). This group of industry, academic, and user representatives has been meeting to define a set of extensions for Fortran dedicated to the special problems posed by a very high performance computers, especially the new generation of parallel computers. The paper describes the HPFF effort and its goals and gives a brief description of the functionality of High Performance Fortran (HPF).

  19. Nonlinear optical transmission of an integrated optical bent coupler in semiconductor-doped glass

    NASA Astrophysics Data System (ADS)

    Guntau, Matthias; Possner, Torsten; Braeuer, Andreas H.; Dannberg, Peter

    1991-08-01

    A technology for monomode slab and strip waveguide fabrication in semiconductor-doped glasses (SDG) is presented. On this basis, directional couplers consisting of both parallel (DC) and bent (BC) couplers of strip waveguides were realized. The optically linear and nonlinear behavior of these devices is described.

  20. High-performance computing — an overview

    NASA Astrophysics Data System (ADS)

    Marksteiner, Peter

    1996-08-01

    An overview of high-performance computing (HPC) is given. Different types of computer architectures used in HPC are discussed: vector supercomputers, high-performance RISC processors, various parallel computers like symmetric multiprocessors, workstation clusters, massively parallel processors. Software tools and programming techniques used in HPC are reviewed: vectorizing compilers, optimization and vector tuning, optimization for RISC processors; parallel programming techniques like shared-memory parallelism, message passing and data parallelism; and numerical libraries.

  1. HOM/LOM Coupler Study for the ILC Crab Cavity

    SciTech Connect

    Xiao, L.; Li, Z.; Ko, K.; /SLAC

    2007-04-16

    The FNAL 9-cell 3.9GHz deflecting mode cavity designed for the CKM experiment was chosen as the baseline design for the ILC BDS crab cavity. The full 9-cell CKM cavity including the coupler end-groups was simulated using the parallel eigensolver Omega3P and scattering parameter solver S3P. It was found that both the notch filters for the HOM/LOM couplers are very sensitive to the notch gap, which is about 1.6MHz/micron and is more than 10 times more sensitive than the TTF cavity. It was also found in the simulation that the unwanted vertical {pi}-mode (SOM) is strongly coupled to the horizontal 7{pi}/9 mode which causes x-y coupling and reduces the effectiveness of the SOM damping. To meet the ILC requirements, the HOM/LOM couplers are redesigned to address these issues. With the new designs, the damping of the HOM/LOM modes is improved. The sensitivity of the notch filter for the HOM coupler is reduced by one order of magnitude. The notch filter for the LOM coupler is eliminated in the new design which significantly simplifies the geometry. In this paper, we will present the simulation results of the original CKM cavity and the progresses on the HOM/LOM coupler re-design and optimization.

  2. Microwave coupler and method

    DOEpatents

    Holcombe, Cressie E.

    1985-01-01

    The present invention is directed to a microwave coupler for enhancing the heating or metallurgical treatment of materials within a cold-wall, rapidly heated cavity as provided by a microwave furnace. The coupling material of the present invention is an alpha-rhombohedral-boron-derivative-structure material such as boron carbide or boron silicide which can be appropriately positioned as a susceptor within the furnace to heat other material or be in powder particulate form so that composites and structures of boron carbide such as cutting tools, grinding wheels and the like can be rapidly and efficiently formed within microwave furnaces.

  3. Microwave coupler and method

    DOEpatents

    Holcombe, C.E.

    1984-11-29

    The present invention is directed to a microwave coupler for enhancing the heating or metallurgical treatment of materials within a cold-wall, rapidly heated cavity as provided by a microwave furnace. The coupling material of the present invention is an alpha-rhombohedral-boron-derivative-structure material such as boron carbide or boron silicide which can be appropriately positioned as a susceptor within the furnace to heat other material or be in powder particulate form so that composites and structures of boron carbide such as cutting tools, grinding wheels and the like can be rapidly and efficiently formed within microwave furnaces.

  4. Multimode waveguide based directional coupler

    NASA Astrophysics Data System (ADS)

    Ahmed, Rajib; Rifat, Ahmmed A.; Sabouri, Aydin; Al-Qattan, Bader; Essa, Khamis; Butt, Haider

    2016-07-01

    The Silicon-on-Insulator (SOI) based platform overcomes limitations of the previous copper and fiber based technologies. Due to its high index difference, SOI waveguide (WG) and directional couplers (DC) are widely used for high speed optical networks and hybrid Electro-Optical inter-connections; TE00-TE01, TE00-TE00 and TM00-TM00 SOI direction couplers are designed with symmetrical and asymmetrical configurations to couple with TE00, TE01 and TM00 in a multi-mode semi-triangular ring-resonator configuration which will be applicable for multi-analyte sensing. Couplers are designed with effective index method and their structural parameters are optimized with consideration to coupler length, wavelength and polarization dependence. Lastly, performance of the couplers are analyzed in terms of cross-talk, mode overlap factor, coupling length and coupling efficiency.

  5. A task-based parallelism and vectorized approach to 3D Method of Characteristics (MOC) reactor simulation for high performance computing architectures

    NASA Astrophysics Data System (ADS)

    Tramm, John R.; Gunow, Geoffrey; He, Tim; Smith, Kord S.; Forget, Benoit; Siegel, Andrew R.

    2016-05-01

    In this study we present and analyze a formulation of the 3D Method of Characteristics (MOC) technique applied to the simulation of full core nuclear reactors. Key features of the algorithm include a task-based parallelism model that allows independent MOC tracks to be assigned to threads dynamically, ensuring load balancing, and a wide vectorizable inner loop that takes advantage of modern SIMD computer architectures. The algorithm is implemented in a set of highly optimized proxy applications in order to investigate its performance characteristics on CPU, GPU, and Intel Xeon Phi architectures. Speed, power, and hardware cost efficiencies are compared. Additionally, performance bottlenecks are identified for each architecture in order to determine the prospects for continued scalability of the algorithm on next generation HPC architectures.

  6. Mid-IR fused fiber couplers

    NASA Astrophysics Data System (ADS)

    Stevens, G.; Woodbridge, T.

    2016-03-01

    We present results from our recent efforts on developing single-mode fused couplers in ZBLAN fibre. We have developed a custom fusion workstation for working with lower melting temperature fibres, such as ZBLAN and chalcogenide fibres. Our workstation uses a precisely controlled electrical heater designed to operate at temperatures between 100 - 250°C as our heat source. The heated region of the fibers was also placed in an inert atmosphere to avoid the formation of microcrystal inclusions during fusion. We firstly developed a process for pulling adiabatic tapers in 6/125 μm ZBLAN fibre. The tapers were measured actively during manufacture using a 2000 nm source. The process was automated so that the heater temperature and motor speed automatically adjusted to pull the taper at constant tension. This process was then further developed so that we could fuse and draw two parallel 6/125 μm ZBLAN fibres, forming a single-mode coupler. Low ratio couplers (1-10%) that could be used as power monitors were manufactured that had an excess loss of 0.76 dB. We have also manufactured 50/50 splitters and wavelength division multiplexers (WDMs). However, the excess loss of these devices was typically 2 - 3 dB. The increased losses were due to localised necking and surface defects forming as the tapers were pulled further to achieve a greater coupling ratio. Initial experiments with chalcogenide fibre have shown that our process can be readily adapted for chalcogenide fibres. A 5% coupler with 1.5 dB insertion loss was manufactured using commercial of the shelf (COTS) fibres.

  7. Task-parallel message passing interface implementation of Autodock4 for docking of very large databases of compounds using high-performance super-computers.

    PubMed

    Collignon, Barbara; Schulz, Roland; Smith, Jeremy C; Baudry, Jerome

    2011-04-30

    A message passing interface (MPI)-based implementation (Autodock4.lga.MPI) of the grid-based docking program Autodock4 has been developed to allow simultaneous and independent docking of multiple compounds on up to thousands of central processing units (CPUs) using the Lamarkian genetic algorithm. The MPI version reads a single binary file containing precalculated grids that represent the protein-ligand interactions, i.e., van der Waals, electrostatic, and desolvation potentials, and needs only two input parameter files for the entire docking run. In comparison, the serial version of Autodock4 reads ASCII grid files and requires one parameter file per compound. The modifications performed result in significantly reduced input/output activity compared with the serial version. Autodock4.lga.MPI scales up to 8192 CPUs with a maximal overhead of 16.3%, of which two thirds is due to input/output operations and one third originates from MPI operations. The optimal docking strategy, which minimizes docking CPU time without lowering the quality of the database enrichments, comprises the docking of ligands preordered from the most to the least flexible and the assignment of the number of energy evaluations as a function of the number of rotatable bounds. In 24 h, on 8192 high-performance computing CPUs, the present MPI version would allow docking to a rigid protein of about 300K small flexible compounds or 11 million rigid compounds. PMID:21387347

  8. Backward Wave Couplers And Reflectors

    NASA Astrophysics Data System (ADS)

    Vassilopoulos, C.; Cozens, J. R.

    1987-09-01

    The analysis and experimental results for weakly perturbed, narrow band, backward wave couplers and fibre reflectors, will be presented. Conventional, co-directional fibre couplers - polished, fused or coaxial - can be designed to demonstrate a sufficient wavelength dependence for some filtering and multiplexing applications. While coupled bandwidths can be sufficiently reduced by weakening the coupling between the guides and hence increasing the interaction (beat) length, useful limits of a few nms are reached for interaction lengths of a few cms. These limitations in coupled bandwidth are considerably transformed for contra-directional coupling provided by a periodic perturbation of suitable pitch (half the guide wavelength) imposed on the coupler. The inverse relationship between bandwidth and interaction length still holds, but the magnitudes are substantially improved. Calculations show that we may expect sub-Angstrom bandwidths for interaction lengths in the order of 1cm. These extremely narrow band effects depend on the successful fabrication of regular, weak, periodic perturbations over relatively long fibre lengths. We have fabricated long gratings (~ 1cm) of periodicity ~ 0.27μm on D-shaped elliptical cored fibres as a first step towards narrow band couplers. These structures can be investigated by observing reflection characteristics at ~ 800nm and the latest results will be described. A contra-directional coupler may then be formed, by joining two dissimilar D-fibres in the polished-coupler configuration with a periodic structure in between them. Additionally, the design of a special twin-core fibre coupler will be described, and its potential as a backward-wave coupler will be examined.

  9. Modern industrial simulation tools: Kernel-level integration of high performance parallel processing, object-oriented numerics, and adaptive finite element analysis. Final report, July 16, 1993--September 30, 1997

    SciTech Connect

    Deb, M.K.; Kennon, S.R.

    1998-04-01

    A cooperative R&D effort between industry and the US government, this project, under the HPPP (High Performance Parallel Processing) initiative of the Dept. of Energy, started the investigations into parallel object-oriented (OO) numerics. The basic goal was to research and utilize the emerging technologies to create a physics-independent computational kernel for applications using adaptive finite element method. The industrial team included Computational Mechanics Co., Inc. (COMCO) of Austin, TX (as the primary contractor), Scientific Computing Associates, Inc. (SCA) of New Haven, CT, Texaco and CONVEX. Sandia National Laboratory (Albq., NM) was the technology partner from the government side. COMCO had the responsibility of the main kernel design and development, SCA had the lead in parallel solver technology and guidance on OO technologies was Sandia`s main expertise in this venture. CONVEX and Texaco supported the partnership by hardware resource and application knowledge, respectively. As such, a minimum of fifty-percent cost-sharing was provided by the industry partnership during this project. This report describes the R&D activities and provides some details about the prototype kernel and example applications.

  10. Polymer waveguide with tunable optofluidic couplers for card-to-backplane optical interconnects

    NASA Astrophysics Data System (ADS)

    Jiang, Guomin; Baig, Sarfaraz; Wang, Michael R.

    2014-03-01

    Polymeric waveguides with tunable optofluidic couplers are fabricated by the vacuum assisted microfluidic technique for card-to-backplane optical interconnect applications. The optofluidic coupler on a backplane consists of polymer waveguides and a perpendicular microfluidic channel with inclined sidewalls. An index matching liquid and air bubbles are located in the microfluidic hollow channel. The activation or deactivation of the surface normal coupling of the optofluidic coupler is accomplished by setting air bubbles or index matching liquid to be in contact with the waveguide mirrors. 10 Gbps eye diagrams of the card-to-backplane optical interconnect link have been demonstrated showing the high performance of the interconnect system.

  11. Efficient waveguide coupler based on metal materials

    NASA Astrophysics Data System (ADS)

    Wu, Wenjun; Yang, Junbo; Chang, Shengli; Zhang, Jingjing; Lu, Huanyu

    2015-10-01

    Because of the diffraction limit of light, the scale of optical element stays in the order of wavelength, which makes the interface optics and nano-electronic components cannot be directly matched, thus the development of photonics technology encounters a bottleneck. In order to solve the problem that coupling of light into the subwavelength waveguide, this paper proposes a model of coupler based on metal materials. By using Surface Plasmon Polaritons (SPPs) wave, incident light can be efficiently coupled into waveguide of diameter less than 100 nm. This paper mainly aims at near infrared wave band, and tests a variety of the combination of metal materials, and by changing the structural parameters to get the maximum coupling efficiency. This structure splits the plane incident light with wavelength of 864 nm, the width of 600 nm into two uniform beams, and separately coupled into the waveguide layer whose width is only about 80 nm, and the highest coupling efficiency can reach above 95%. Using SPPs structure will be an effective method to break through the diffraction limit and implement photonics device high-performance miniaturization. We can further compress the light into small scale fiber or waveguide by using the metal coupler, and to save the space to hold more fiber or waveguide layer, so that we can greatly improve the capacity of optical communication. In addition, high-performance miniaturization of the optical transmission medium can improve the integration of optical devices, also provide a feasible solution for the photon computer research and development in the future.

  12. Wireless power transfer magnetic couplers

    DOEpatents

    Wu, Hunter; Gilchrist, Aaron; Sealy, Kylee

    2016-01-19

    A magnetic coupler is disclosed for wireless power transfer systems. A ferrimagnetic component is capable of guiding a magnetic field. A wire coil is wrapped around at least a portion of the ferrimagnetic component. A screen is capable of blocking leakage magnetic fields. The screen may be positioned to cover at least one side of the ferrimagnetic component and the coil. A distance across the screen may be at least six times an air gap distance between the ferrimagnetic component and a receiving magnetic coupler.

  13. Power coupler for the ILC crab cavity

    SciTech Connect

    Burt, G.; Dexter, A.; Jenkins, R.; Beard, C.; Goudket, P.; McIntosh, P.A.; Bellantoni, Leo; /Fermilab

    2007-06-01

    The ILC crab cavity will require the design of an appropriate power coupler. The beam-loading in dipole mode cavities is considerably more variable than accelerating cavities, hence simulations have been performed to establish the required external Q. Simulations of a suitable coupler were then performed and were verified using a normal conducting prototype with variable coupler tips.

  14. High Performance Tools And Technologies

    SciTech Connect

    Collette, M R; Corey, I R; Johnson, J R

    2005-01-24

    This goal of this project was to evaluate the capability and limits of current scientific simulation development tools and technologies with specific focus on their suitability for use with the next generation of scientific parallel applications and High Performance Computing (HPC) platforms. The opinions expressed in this document are those of the authors, and reflect the authors' current understanding and functionality of the many tools investigated. As a deliverable for this effort, we are presenting this report describing our findings along with an associated spreadsheet outlining current capabilities and characteristics of leading and emerging tools in the high performance computing arena. This first chapter summarizes our findings (which are detailed in the other chapters) and presents our conclusions, remarks, and anticipations for the future. In the second chapter, we detail how various teams in our local high performance community utilize HPC tools and technologies, and mention some common concerns they have about them. In the third chapter, we review the platforms currently or potentially available to utilize these tools and technologies on to help in software development. Subsequent chapters attempt to provide an exhaustive overview of the available parallel software development tools and technologies, including their strong and weak points and future concerns. We categorize them as debuggers, memory checkers, performance analysis tools, communication libraries, data visualization programs, and other parallel development aides. The last chapter contains our closing information. Included with this paper at the end is a table of the discussed development tools and their operational environment.

  15. A modified lower hybrid coupler for TPX

    SciTech Connect

    Bernabei, S.; Greenough, N.; Goranson, P.; Swain, D.

    1995-07-01

    Efforts have concentrated on redesigning the configuration of the Lower Hybrid coupler for TPX tokamak. Several concerns motivated this redesign: reduce the effect of thermal incompatibility between coupler and rf-window material, reduce weight, reduce the risk of wind failure and address the problem of replaceability, increase the reliability by reducing the number connections and finally, reduce the total cost. The result is a highly compact, light and easily serviceable coupler which incorporates some of the simplicity of the multifunction coupler but preserves the spectral flexibility of a conventional coupler.

  16. Hearing aid coupler output level variability and coupler correction levels for insert earphones.

    PubMed

    Frank, T; Richards, W D

    1991-06-01

    HA coupler type SPLs were independently determined by two experimenters for five repeated measurements with and without replacement of two ER-3A and two EARTONE 3A insert earphones. Measurements were made using a B&K DB-0138 coupler configured as an HA-1, HA-2 earphone coupler and HA-2 earphone coupler with entrance through a rigid tube referred to as the DB-0138 coupler. The HA-1, HA-2, and DB-0138 SPLs were found to be very stable (+/- 0.2 dB) for all intra- and interexperimenter measurements for each insert earphone and coupler type from 125 to 8000 Hz. Averaged across both experimenters and all repeated measurements, the mean HA-1 and HA-2 coupler SPLs were similar for each insert earphone from 125 to 8000 Hz. The mean HA-1, HA-2, and DB-0138 coupler SPLs were similar for each insert earphone from 125 to 2000 Hz; however, from 3000 to 8000 Hz the DB-0138 coupler SPLs were higher than the HA-1 and HA-2 coupler SPLs for each insert earphone. This occurred because of the geometrical differences between the insert earphone to coupler connections and coupler types. The HA-1 minus DB-0138 and HA-2 minus DB-0138 coupler SPL differences, or coupler correction levels, could be explained by quarter-wave resonances and stepped-diameter tubing systems creating acoustic horn effects. PMID:1916048

  17. A linear atomic quantum coupler

    NASA Astrophysics Data System (ADS)

    El-Orany, Faisal A. A.; Wahiddin, M. R. B.

    2010-04-01

    In this paper we develop the notion of the linear atomic quantum coupler. This device consists of two modes propagating into two waveguides, each of which includes a localized atom. These waveguides are placed close enough to allow exchange of energy between them via evanescent waves. Each mode interacts with the atom in the same waveguide in the standard way as the Jaynes-Cummings model (JCM) and with the atom-mode system in the second waveguide via the evanescent wave. We present the Hamiltonian for this system and deduce its wavefunction. We investigate the atomic inversions and the second-order correlation function. In contrast to the conventional coupler the atomic quantum coupler is able to generate nonclassical effects. The atomic inversions can exhibit a long revival-collapse phenomenon as well as subsidiary revivals based on the competition among the switching mechanisms in the system. Finally, under certain conditions the system can yield the results of the two-mode JCM.

  18. Side polished twin-core fiber coupler

    NASA Astrophysics Data System (ADS)

    Wang, Xianbin; Yuan, Libo

    2015-07-01

    A novel optical fiber coupler was proposed and fabricated for coupling each core of a twin-core fiber (TCF) with a single-core fiber (SCF) core simultaneously and accessing independently both cores of the TCF. The coupler is mainly composed of two sides polished SCF and a side polished TCF. Each optical field launched from the TCF could be coupled into the side polished SCF. The coupler has a simple structure and less cross-talk between the two cores.

  19. High performance polymer development

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M.

    1991-01-01

    The term high performance as applied to polymers is generally associated with polymers that operate at high temperatures. High performance is used to describe polymers that perform at temperatures of 177 C or higher. In addition to temperature, other factors obviously influence the performance of polymers such as thermal cycling, stress level, and environmental effects. Some recent developments at NASA Langley in polyimides, poly(arylene ethers), and acetylenic terminated materials are discussed. The high performance/high temperature polymers discussed are representative of the type of work underway at NASA Langley Research Center. Further improvement in these materials as well as the development of new polymers will provide technology to help meet NASA future needs in high performance/high temperature applications. In addition, because of the combination of properties offered by many of these polymers, they should find use in many other applications.

  20. High Performance Polymers

    NASA Technical Reports Server (NTRS)

    Venumbaka, Sreenivasulu R.; Cassidy, Patrick E.

    2003-01-01

    This report summarizes results from research on high performance polymers. The research areas proposed in this report include: 1) Effort to improve the synthesis and to understand and replicate the dielectric behavior of 6HC17-PEK; 2) Continue preparation and evaluation of flexible, low dielectric silicon- and fluorine- containing polymers with improved toughness; and 3) Synthesis and characterization of high performance polymers containing the spirodilactam moiety.

  1. A terahertz broadband 3 dB directional coupler based on bridged PPDW.

    PubMed

    Ye, Longfang; Zhang, Yong; Xu, Ruimin; Lin, Weigan

    2011-09-26

    In this paper, a novel broadband 3 dB directional coupler with very flat coupling based on bridged parallel plate dielectric waveguide (PPDW) is proposed and demonstrated. In the uniform coupling section, a bridge structure between the two PPDWs is employed to obtain accurate coupling value and achieve a broadband coupling. It is found that this new type of coupling structure exhibits excellent performance at terahertz frequencies. In order to achieve strong isolation between the adjacent ports and reduce the power reflection in all ports, two quarter-circle bend arms are introduced as the curved transition sections to connect the uniform coupling section. For this bridged coupler, it only needs the value of the uniform coupling length as short as 400 μm to achieve a broadband 3 dB coupling. In this case, the coupler's average return loss is greater than 28 dB, average isolation is better than 27 dB and average coupler loss is only 0.9 dB, over a percentage bandwidth of 12.5% at 1 THz. Compared to the conventional PPDW coupler, the bridged PPDW coupler shows significantly greater bandwidth (about 4.2 times), compact and mechanically stable with a much shorter uniform coupling length (reduced about 61%), which may have potential applications for terahertz integrated circuits and systems. PMID:21996833

  2. 49 CFR 215.123 - Defective couplers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components Draft System § 215.123 Defective couplers. A railroad may not place or continue in service a car, if— (a) The car is... automatically with the adjacent car; (b) The car has a coupler that has a crack in the highly stressed...

  3. 49 CFR 215.123 - Defective couplers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Defective couplers. 215.123 Section 215.123 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....123 Defective couplers. A railroad may not place or continue in service a car, if— (a) The car...

  4. 49 CFR 215.123 - Defective couplers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Defective couplers. 215.123 Section 215.123 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....123 Defective couplers. A railroad may not place or continue in service a car, if— (a) The car...

  5. 49 CFR 215.123 - Defective couplers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Defective couplers. 215.123 Section 215.123 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....123 Defective couplers. A railroad may not place or continue in service a car, if— (a) The car...

  6. 49 CFR 215.123 - Defective couplers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Defective couplers. 215.123 Section 215.123 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....123 Defective couplers. A railroad may not place or continue in service a car, if— (a) The car...

  7. High-Performance Happy

    ERIC Educational Resources Information Center

    O'Hanlon, Charlene

    2007-01-01

    Traditionally, the high-performance computing (HPC) systems used to conduct research at universities have amounted to silos of technology scattered across the campus and falling under the purview of the researchers themselves. This article reports that a growing number of universities are now taking over the management of those systems and…

  8. High performance systems

    SciTech Connect

    Vigil, M.B.

    1995-03-01

    This document provides a written compilation of the presentations and viewgraphs from the 1994 Conference on High Speed Computing given at the High Speed Computing Conference, {open_quotes}High Performance Systems,{close_quotes} held at Gleneden Beach, Oregon, on April 18 through 21, 1994.

  9. High Speed Data Bus Active Coupler

    NASA Astrophysics Data System (ADS)

    Herrmann, James J.

    The author discusses the HSDB (high speed data bus) active coupler which provides a typical 13-dB power margin for HSDB systems installed in military aircraft. This high-power margin ensures reliable HSDB operation through fiber-optic component degradation. The active coupler performs optical amplification and signal reshaping functions such that an incoming signal is modified only in amplitude. Signal distortion and jitter are removed by a retiming ASIC (application-specific integrated circuit). The active coupler is modular in design, and plug-in growth for a 38 x 38 user interface is available. The active coupler achieves better than -27 dBm sensitivity at 5 x 10 exp -11 bit error rate and outputs -8 to -12 dBm optical power. The active coupler unit weighs only 6.25 lbs and has a predicted mean time between failure of over 21,000 h.

  10. Optical Waveguide Output Couplers Fabricated in Polymers

    NASA Technical Reports Server (NTRS)

    Watson, Michael D.; Abushagur, Mustafa A. G.; Ashley, Paul R.; Johnson-Cole, Helen

    1998-01-01

    Waveguide output couplers fabricated in Norland Optical Adhesive (NOA) #81 and AMOCO Ultradel 9020D polyimide are investigated. The output couplers are implemented using periodic relief gratings on a planar waveguide. Design theory of the couplers is based on the perturbation approach. Coupling of light from waveguide propagation modes to output radiation modes is described by coupled mode theory and the transmission line approximation of the perturbed area (grating structure). Using these concepts, gratings can be accurately designed to output a minimum number of modes at desired output angles. Waveguide couplers were designed using these concepts. These couplers were fabricated and analyzed for structural accuracy, output beam accuracy, and output efficiency. The results for the two different materials are compared.

  11. High Power Co-Axial Coupler

    SciTech Connect

    Neubauer, M.; Dudas, A.; Rimmer, Robert A.; Guo, Jiquan; Williams, R. Scott

    2013-12-01

    A very high power Coax RF Coupler (MW-Level) is very desirable for a number of accelerator and commercial applications. For example, the development of such a coupler operating at 1.5 GHz may permit the construction of a higher-luminosity version of the Electron-Ion Collider (EIC) being planned at JLab. Muons, Inc. is currently funded by a DOE STTR grant to develop a 1.5-GHz high-power doublewindowcoax coupler with JLab (about 150 kW). Excellent progress has been made on this R&D project, so we propose an extension of this development to build a very high power coax coupler (MW level peak power and a max duty factor of about 4%). The dimensions of the current coax coupler will be scaled up to provide higher power capability.

  12. High Performance, Dependable Multiprocessor

    NASA Technical Reports Server (NTRS)

    Ramos, Jeremy; Samson, John R.; Troxel, Ian; Subramaniyan, Rajagopal; Jacobs, Adam; Greco, James; Cieslewski, Grzegorz; Curreri, John; Fischer, Michael; Grobelny, Eric; George, Alan; Aggarwal, Vikas; Patel, Minesh; Some, Raphael

    2006-01-01

    With the ever increasing demand for higher bandwidth and processing capacity of today's space exploration, space science, and defense missions, the ability to efficiently apply commercial-off-the-shelf (COTS) processors for on-board computing is now a critical need. In response to this need, NASA's New Millennium Program office has commissioned the development of Dependable Multiprocessor (DM) technology for use in payload and robotic missions. The Dependable Multiprocessor technology is a COTS-based, power efficient, high performance, highly dependable, fault tolerant cluster computer. To date, Honeywell has successfully demonstrated a TRL4 prototype of the Dependable Multiprocessor [I], and is now working on the development of a TRLS prototype. For the present effort Honeywell has teamed up with the University of Florida's High-performance Computing and Simulation (HCS) Lab, and together the team has demonstrated major elements of the Dependable Multiprocessor TRLS system.

  13. High performance polymeric foams

    SciTech Connect

    Gargiulo, M.; Sorrentino, L.; Iannace, S.

    2008-08-28

    The aim of this work was to investigate the foamability of high-performance polymers (polyethersulfone, polyphenylsulfone, polyetherimide and polyethylenenaphtalate). Two different methods have been used to prepare the foam samples: high temperature expansion and two-stage batch process. The effects of processing parameters (saturation time and pressure, foaming temperature) on the densities and microcellular structures of these foams were analyzed by using scanning electron microscopy.

  14. High Performance Proactive Digital Forensics

    NASA Astrophysics Data System (ADS)

    Alharbi, Soltan; Moa, Belaid; Weber-Jahnke, Jens; Traore, Issa

    2012-10-01

    With the increase in the number of digital crimes and in their sophistication, High Performance Computing (HPC) is becoming a must in Digital Forensics (DF). According to the FBI annual report, the size of data processed during the 2010 fiscal year reached 3,086 TB (compared to 2,334 TB in 2009) and the number of agencies that requested Regional Computer Forensics Laboratory assistance increasing from 689 in 2009 to 722 in 2010. Since most investigation tools are both I/O and CPU bound, the next-generation DF tools are required to be distributed and offer HPC capabilities. The need for HPC is even more evident in investigating crimes on clouds or when proactive DF analysis and on-site investigation, requiring semi-real time processing, are performed. Although overcoming the performance challenge is a major goal in DF, as far as we know, there is almost no research on HPC-DF except for few papers. As such, in this work, we extend our work on the need of a proactive system and present a high performance automated proactive digital forensic system. The most expensive phase of the system, namely proactive analysis and detection, uses a parallel extension of the iterative z algorithm. It also implements new parallel information-based outlier detection algorithms to proactively and forensically handle suspicious activities. To analyse a large number of targets and events and continuously do so (to capture the dynamics of the system), we rely on a multi-resolution approach to explore the digital forensic space. Data set from the Honeynet Forensic Challenge in 2001 is used to evaluate the system from DF and HPC perspectives.

  15. High-performance combinatorial algorithms

    SciTech Connect

    Pinar, Ali

    2003-10-31

    Combinatorial algorithms have long played an important role in many applications of scientific computing such as sparse matrix computations and parallel computing. The growing importance of combinatorial algorithms in emerging applications like computational biology and scientific data mining calls for development of a high performance library for combinatorial algorithms. Building such a library requires a new structure for combinatorial algorithms research that enables fast implementation of new algorithms. We propose a structure for combinatorial algorithms research that mimics the research structure of numerical algorithms. Numerical algorithms research is nicely complemented with high performance libraries, and this can be attributed to the fact that there are only a small number of fundamental problems that underlie numerical solvers. Furthermore there are only a handful of kernels that enable implementation of algorithms for these fundamental problems. Building a similar structure for combinatorial algorithms will enable efficient implementations for existing algorithms and fast implementation of new algorithms. Our results will promote utilization of combinatorial techniques and will impact research in many scientific computing applications, some of which are listed.

  16. Miniature mechanical transfer optical coupler

    DOEpatents

    Abel, Philip; Watterson, Carl

    2011-02-15

    A miniature mechanical transfer (MT) optical coupler ("MMTOC") for optically connecting a first plurality of optical fibers with at least one other plurality of optical fibers. The MMTOC may comprise a beam splitting element, a plurality of collimating lenses, and a plurality of alignment elements. The MMTOC may optically couple a first plurality of fibers disposed in a plurality of ferrules of a first MT connector with a second plurality of fibers disposed in a plurality of ferrules of a second MT connector and a third plurality of fibers disposed in a plurality of ferrules of a third MT connector. The beam splitting element may allow a portion of each beam of light from the first plurality of fibers to pass through to the second plurality of fibers and simultaneously reflect another portion of each beam of light from the first plurality of fibers to the third plurality of fibers.

  17. High performance steam development

    SciTech Connect

    Duffy, T.; Schneider, P.

    1995-12-31

    DOE has launched a program to make a step change in power plant to 1500 F steam, since the highest possible performance gains can be achieved in a 1500 F steam system when using a topping turbine in a back pressure steam turbine for cogeneration. A 500-hour proof-of-concept steam generator test module was designed, fabricated, and successfully tested. It has four once-through steam generator circuits. The complete HPSS (high performance steam system) was tested above 1500 F and 1500 psig for over 102 hours at full power.

  18. High Performance Liquid Chromatography

    NASA Astrophysics Data System (ADS)

    Talcott, Stephen

    High performance liquid chromatography (HPLC) has many applications in food chemistry. Food components that have been analyzed with HPLC include organic acids, vitamins, amino acids, sugars, nitrosamines, certain pesticides, metabolites, fatty acids, aflatoxins, pigments, and certain food additives. Unlike gas chromatography, it is not necessary for the compound being analyzed to be volatile. It is necessary, however, for the compounds to have some solubility in the mobile phase. It is important that the solubilized samples for injection be free from all particulate matter, so centrifugation and filtration are common procedures. Also, solid-phase extraction is used commonly in sample preparation to remove interfering compounds from the sample matrix prior to HPLC analysis.

  19. Numerical simulation of coupler cavities for linacs

    SciTech Connect

    Ng, C.K.; Derutyer, H.; Ko, K.

    1993-04-01

    We present numerical procedures involved in the evaluation of the performance of coupler cavities for linacs. The MAFIA code is used to simulate an X-Band accelerator section in the time domain. The input/output coupler cavities for the structure arc of the symmetrical double-input design. We calculate the transmission properties of the coupler and compare the results with measurements. We compare the performance of the symmetrical double-input design with that of the conventional single-input type by evaluating the field amplitude and phase asymmetries. We also evaluate the peak field gradient in the computer.

  20. rf coupler technology for fusion applications

    SciTech Connect

    Hoffman, D.J.

    1983-01-01

    Radio frequency (rf) oscillations at critical frequencies have successfully provided a means to convey power to fusion plasmas due to the electrical-magnetic properties of the plasma. While large rf systems to couple power to the plasma have been designed, built, and tested, the main link to the plasma, the coupler, is still in an evolutionary stage of development. Design and fabrication of optimal antennas for fusion applications are complicated by incomplete characterizations of the harsh plasma environment and of coupling mechanisms. A brief description of rf coupler technology required for plasma conditions is presented along with an assessment of the status and goals of coupler development.

  1. Overview of recent HOM coupler development

    SciTech Connect

    Xiao, B.

    2015-09-13

    Higher Order Mode (HOM) damping is important for SRF applications, especially for high-intensity machines. A good HOM damping design will help to reduce power load to the cryogenic system and to reduce the risk of beam breakup. The design of HOM damping, including antenna/loop HOM couplers, beam pipe HOM absorbers and waveguide HOM couplers, is to solve a multi-physics problem that involves RF, thermal, mechanical, and beam-cavity interaction issues. In this talk, the author provides an overview on the latest advances of the HOM couplers for high-intensity SRF applications.

  2. Multiport waveguide couplers with periodic energy exchange.

    PubMed

    Petrovic, Jovana

    2015-01-15

    In this Letter, a multiport directional optical coupler based on periodic energy exchange in a linear waveguide array is proposed. The periodic power transfer is achieved by choosing waveguide separations that render commensurate eigenvalues of the array coupling matrix. This is a general solution and offers a plethora of possibilities. Particularly interesting is an array that can be used to realize different couplers by simply choosing a different input waveguide. The proposed design principle is validated by full numerical simulations of realistic devices and the required fabrication precision is estimated. The proposed couplers are of interest for quantum optics, biosensing, and communications. PMID:25679828

  3. High Performance Buildings Database

    DOE Data Explorer

    The High Performance Buildings Database is a shared resource for the building industry, a unique central repository of in-depth information and data on high-performance, green building projects across the United States and abroad. The database includes information on the energy use, environmental performance, design process, finances, and other aspects of each project. Members of the design and construction teams are listed, as are sources for additional information. In total, up to twelve screens of detailed information are provided for each project profile. Projects range in size from small single-family homes or tenant fit-outs within buildings to large commercial and institutional buildings and even entire campuses. The database is a data repository as well. A series of Web-based data-entry templates allows anyone to enter information about a building project into the database. Once a project has been submitted, each of the partner organizations can review the entry and choose whether or not to publish that particular project on its own Web site.

  4. High Performance Window Retrofit

    SciTech Connect

    Shrestha, Som S; Hun, Diana E; Desjarlais, Andre Omer

    2013-12-01

    The US Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) and Traco partnered to develop high-performance windows for commercial building that are cost-effective. The main performance requirement for these windows was that they needed to have an R-value of at least 5 ft2 F h/Btu. This project seeks to quantify the potential energy savings from installing these windows in commercial buildings that are at least 20 years old. To this end, we are conducting evaluations at a two-story test facility that is representative of a commercial building from the 1980s, and are gathering measurements on the performance of its windows before and after double-pane, clear-glazed units are upgraded with R5 windows. Additionally, we will use these data to calibrate EnergyPlus models that we will allow us to extrapolate results to other climates. Findings from this project will provide empirical data on the benefits from high-performance windows, which will help promote their adoption in new and existing commercial buildings. This report describes the experimental setup, and includes some of the field and simulation results.

  5. Experimental demonstration of ultra-wideband and high-efficiency terahertz spoof surface plasmon polaritons coupler

    NASA Astrophysics Data System (ADS)

    Tang, Heng-He; Ma, Tian-Jun; Liu, Pu-Kun

    2016-05-01

    Spoof surface plasmon polaritons (SSPPs) are promising for subwavelength waveguiding in the terahertz (THz) frequency range. However, they cannot be efficiently excited from spatial propagating or guided waves due to the mismatched momenta. In this paper, a THz coupler is designed to smoothly bridge SSPPs and guided (or propagating) waves. By using a tapered parallel-plate waveguide, the incident energies are efficiently compressed and coupled into a subwavelength gap. Then, the momenta differences are mitigated with a graded grating. The numerical simulations show that the relative bandwidth of the coupler reaches up to 127%, and the maximum coupling efficiency is 99%. More importantly, experiment results in the 0.22 THz-0.33 THz frequency range are also presented to verify the good performance of the coupler. The work provides a technical support for terahertz waveguiding.

  6. Folded waveguide coupler for ion cyclotron heating

    SciTech Connect

    Owens, T.L.; Chen, G.L.

    1986-01-01

    A new type of waveguide coupler for plasma heating in the ion cyclotron range of frequencies is described. The coupler consists of a series of interleaved metallic vanes within a rectangular enclosure analogous to a wide rectangular waveguide that has been ''folded'' several times. At the mouth of the coupler, a plate is attached which contains coupling apertures in each fold or every other fold of the waveguide, depending upon the wavenumber spectrum desired. This plate serves primarily as a wave field polarizer that converts coupler fields to the polarization of the fast magnetosonic wave within the plasma. Theoretical estimates indicate that the folded waveguide is capable of high-efficiency, multimegawatt operation into a plasma. Bench tests have verified the predicted field structure within the waveguide in preparation for high-power tests on the Radio Frequency Test Facility at the Oak Ridge National Laboratory.

  7. Rotating optical coupler for signal transmission

    NASA Technical Reports Server (NTRS)

    Ivie, C. V.

    1977-01-01

    Optical coupler using Dove prism assembly to form stationary image of rotating object, transmits data across rotating interface without sliprings or other mechanical contacts. Device can handle many high-bit-rate data channels.

  8. A Tandem Coupler for Terahertz Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Reck, Theodore J.; Deal, William; Chattopadhyay, Goutam

    2013-01-01

    A coplanar waveguide 3 dB quadrature coupler operating from 500 to 700 GHz is designed, fabricated and measured. On-wafer measurements demonstrate an amplitude balance of +/-2 dB and phase balance of +/-20 deg.

  9. Interactions of spatial solitons with fused couplers

    NASA Astrophysics Data System (ADS)

    Harel, Alon; Malomed, Boris A.

    2014-04-01

    We study dynamical and stationary states of solitons in dual-core waveguides which are locally coupled (fused) at one or several short segments. The model applies to planar optical waveguides, and to Bose-Einstein condensate in dual traps. Collisions of an incident soliton with single and double locally fused couplers are investigated by means of systematic simulations and several analytical methods (quasilinear, fast-soliton, and adiabatic approximations). Excitation dynamics of a soliton trapped by a local coupler is studied by means of the variational approximation, and verified by simulations. Shuttle motion of a soliton trapped in a cavity between two local couplers, and in a finite array of couplers, is studied too.

  10. General lossless planar coupler design algorithms.

    PubMed

    Vance, Rod

    2015-08-01

    This paper reviews and extends two classes of algorithms for the design of planar couplers with any unitary transfer matrix as design goals. Such couplers find use in optical sensing for fading free interferometry, coherent optical network demodulation, and also for quantum state preparation in quantum optical experiments and technology. The two classes are (1) "atomic coupler algorithms" decomposing a unitary transfer matrix into a planar network of 2×2 couplers, and (2) "Lie theoretic algorithms" concatenating unit cell devices with variable phase delay sets that form canonical coordinates for neighborhoods in the Lie group U(N), so that the concatenations realize any transfer matrix in U(N). As well as review, this paper gives (1) a Lie theoretic proof existence proof showing that both classes of algorithms work and (2) direct proofs of the efficacy of the "atomic coupler" algorithms. The Lie theoretic proof strengthens former results. 5×5 couplers designed by both methods are compared by Monte Carlo analysis, which would seem to imply atomic rather than Lie theoretic methods yield designs more resilient to manufacturing imperfections. PMID:26367295

  11. High performance sapphire windows

    NASA Technical Reports Server (NTRS)

    Bates, Stephen C.; Liou, Larry

    1993-01-01

    High-quality, wide-aperture optical access is usually required for the advanced laser diagnostics that can now make a wide variety of non-intrusive measurements of combustion processes. Specially processed and mounted sapphire windows are proposed to provide this optical access to extreme environment. Through surface treatments and proper thermal stress design, single crystal sapphire can be a mechanically equivalent replacement for high strength steel. A prototype sapphire window and mounting system have been developed in a successful NASA SBIR Phase 1 project. A large and reliable increase in sapphire design strength (as much as 10x) has been achieved, and the initial specifications necessary for these gains have been defined. Failure testing of small windows has conclusively demonstrated the increased sapphire strength, indicating that a nearly flawless surface polish is the primary cause of strengthening, while an unusual mounting arrangement also significantly contributes to a larger effective strength. Phase 2 work will complete specification and demonstration of these windows, and will fabricate a set for use at NASA. The enhanced capabilities of these high performance sapphire windows will lead to many diagnostic capabilities not previously possible, as well as new applications for sapphire.

  12. High Performance Network Monitoring

    SciTech Connect

    Martinez, Jesse E

    2012-08-10

    Network Monitoring requires a substantial use of data and error analysis to overcome issues with clusters. Zenoss and Splunk help to monitor system log messages that are reporting issues about the clusters to monitoring services. Infiniband infrastructure on a number of clusters upgraded to ibmon2. ibmon2 requires different filters to report errors to system administrators. Focus for this summer is to: (1) Implement ibmon2 filters on monitoring boxes to report system errors to system administrators using Zenoss and Splunk; (2) Modify and improve scripts for monitoring and administrative usage; (3) Learn more about networks including services and maintenance for high performance computing systems; and (4) Gain a life experience working with professionals under real world situations. Filters were created to account for clusters running ibmon2 v1.0.0-1 10 Filters currently implemented for ibmon2 using Python. Filters look for threshold of port counters. Over certain counts, filters report errors to on-call system administrators and modifies grid to show local host with issue.

  13. Coupler induced monopole component and its minimization in deflecting cavities

    NASA Astrophysics Data System (ADS)

    Ambattu, P. K.; Burt, G.; Grudiev, A.; Dolgashev, V.; Dexter, A.

    2013-06-01

    Deflecting cavities are used in particle accelerators for the manipulation of charged particles by deflecting or crabbing (rotating) them. For short deflectors, the effect of the power coupler on the deflecting field can become significant. The particular power coupler type can introduce multipole rf field components and coupler-specific wakefields. Coupler types that would normally be considered like standard on-cell coupler, waveguide coupler, or mode-launcher coupler could have one or two rf feeds. The major advantage of a dual-feed coupler is the absence of monopole and quadrupole rf field components in the deflecting structure. However, a dual-feed coupler is mechanically more complex than a typical single-feed coupler and needs a splitter. For most applications, deflecting structures are placed in regions where there is small space hence reducing the size of the structure is very desirable. This paper investigates the multipole field components of the deflecting mode in single-feed couplers and ways to overcome the effect of the monopole component on the beam. Significant advances in performance have been demonstrated. Additionally, a novel coupler design is introduced which has no monopole field component to the deflecting mode and is more compact than the conventional dual-feed coupler.

  14. Simplified flangeless unisex waveguide coupler assembly

    DOEpatents

    Michelangelo, D.; Moeller, C.P.

    1993-05-04

    A unisex coupler assembly is disclosed capable of providing a leak tight coupling for waveguides with axial alignment of the waveguides and rotational capability. The sealing means of the coupler assembly are not exposed to RF energy, and the coupler assembly does not require the provision of external flanges on the waveguides. In a preferred embodiment, O ring seals are not used and the coupler assembly is, therefore, bakeable at a temperature up to about 150 C. The coupler assembly comprises a split collar which clamps around the waveguides and a second collar which fastens to the split collar. The split collar contains an inner annular groove. Each of the waveguides is provided with an external annular groove which receives a retaining ring. The split collar is clamped around one of the waveguides with the inner annular groove of the split collar engaging the retaining ring carried in the external annular groove in the waveguide. The second collar is then slipped over the second waveguide behind the annular groove and retaining ring therein and the second collar is coaxially secured by fastening means to the split collar to draw the respective waveguides together by coaxial force exerted by the second collar against the retaining ring on the second waveguide. A sealing ring is placed against an external sealing surface at a reduced external diameter end formed on one waveguide to sealingly engage a corresponding sealing surface on the other waveguide as the waveguides are urged toward each other.

  15. Simplified flangeless unisex waveguide coupler assembly

    DOEpatents

    Michelangelo, Dimartino; Moeller, Charles P.

    1993-01-01

    A unisex coupler assembly is disclosed capable of providing a leak tight coupling for waveguides with axial alignment of the waveguides and rotational capability. The sealing means of the coupler assembly are not exposed to RF energy, and the coupler assembly does not require the provision of external flanges on the waveguides. In a preferred embodiment, O ring seals are not used and the coupler assembly is, therefore, bakeable at a temperature up to about 150.degree. C. The coupler assembly comprises a split collar which clamps around the waveguides and a second collar which fastens to the split collar. The split collar contains an inner annular groove. Each of the waveguides is provided with an external annular groove which receives a retaining ring. The split collar is clamped around one of the waveguides with the inner annular groove of the split collar engaging the retaining ring carried in the external annular groove in the waveguide. The second collar is then slipped over the second waveguide behind the annular groove and retaining ring therein and the second collar is coaxially secured by fastening means to the split collar to draw the respective waveguides together by coaxial force exerted by the second collar against the retaining ring on the second waveguide. A sealing ring is placed against an external sealing surface at a reduced external diameter end formed on one waveguide to sealingly engage a corresponding sealing surface on the other waveguide as the waveguides are urged toward each other.

  16. Evaluation of high-performance computing software

    SciTech Connect

    Browne, S.; Dongarra, J.; Rowan, T.

    1996-12-31

    The absence of unbiased and up to date comparative evaluations of high-performance computing software complicates a user`s search for the appropriate software package. The National HPCC Software Exchange (NHSE) is attacking this problem using an approach that includes independent evaluations of software, incorporation of author and user feedback into the evaluations, and Web access to the evaluations. We are applying this approach to the Parallel Tools Library (PTLIB), a new software repository for parallel systems software and tools, and HPC-Netlib, a high performance branch of the Netlib mathematical software repository. Updating the evaluations with feed-back and making it available via the Web helps ensure accuracy and timeliness, and using independent reviewers produces unbiased comparative evaluations difficult to find elsewhere.

  17. Commoditization of High Performance Storage

    SciTech Connect

    Studham, Scott S.

    2004-04-01

    The commoditization of high performance computers started in the late 80s with the attack of the killer micros. Previously, high performance computers were exotic vector systems that could only be afforded by an illustrious few. Now everyone has a supercomputer composed of clusters of commodity processors. A similar commoditization of high performance storage has begun. Commodity disks are being used for high performance storage, enabling a paradigm change in storage and significantly changing the price point of high volume storage.

  18. Organic magnetic diradicals (radical-coupler-radical): standardization of couplers for strong ferromagnetism.

    PubMed

    Cho, Daeheum; Ko, Kyoung Chul; Lee, Jin Yong

    2014-07-10

    The intramolecular magnetic coupling constant (J) values of sets of diradicals linked to bis-DTDA, OVER, and NN radicals (DTDA, OVER, and NN groups) through an aromatic coupler were studied by unrestricted density functional theory calculations (UB3LYP/6-311++G(d,p)). Among 15 aromatic couplers, 9 compounds with an odd number of carbon atoms along its spin coupling path were found to interact ferromagnetically upon coupling with bisradicals while the other 6 couplers with an even number of carbon atoms along its spin coupling path give rise to antiferromagnetic coupling. The overall trends in the strength of magnetic interactions of aromatic couplers were preserved for DTDA, OVER, and NN groups so that the trend can be utilized as an index for the magnetic strength of a given coupler. It was found that the differences in the nucleus-independent chemical shift (NICS), bond order of connecting bonds, and Mulliken atomic spin density at connected atoms between triplet and BS states are closely related to the intramolecular magnetic behavior. 2,4- and 2,5-phosphole couplers exhibit the strongest intramolecular ferromagnetic and antiferromagnetic interactions among 15 aromatic couplers when linked to diverse bisradicals. PMID:24936749

  19. High Performance Input/Output Systems for High Performance Computing and Four-Dimensional Data Assimilation

    NASA Technical Reports Server (NTRS)

    Fox, Geoffrey C.; Ou, Chao-Wei

    1997-01-01

    The approach of this task was to apply leading parallel computing research to a number of existing techniques for assimilation, and extract parameters indicating where and how input/output limits computational performance. The following was used for detailed knowledge of the application problems: 1. Developing a parallel input/output system specifically for this application 2. Extracting the important input/output characteristics of data assimilation problems; and 3. Building these characteristics s parameters into our runtime library (Fortran D/High Performance Fortran) for parallel input/output support.

  20. High power couplers for Project X

    SciTech Connect

    Kazakov, S.; Champion, M.S.; Yakovlev, V.P.; Kramp, M.; Pronitchev, O.; Orlov, Y.; /Fermilab

    2011-03-01

    Project X, a multi-megawatt proton source under development at Fermi National Accelerator Laboratory. The key element of the project is a superconducting (SC) 3GV continuous wave (CW) proton linac. The linac includes 5 types of SC accelerating cavities of two frequencies.(325 and 650MHz) The cavities consume up to 30 kW average RF power and need proper main couplers. Requirements and approach to the coupler design are discussed in the report. New cost effective schemes are described. Results of electrodynamics and thermal simulations are presented.

  1. High Performance Fortran for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Mehrotra, Piyush; Zima, Hans; Bushnell, Dennis M. (Technical Monitor)

    2000-01-01

    This paper focuses on the use of High Performance Fortran (HPF) for important classes of algorithms employed in aerospace applications. HPF is a set of Fortran extensions designed to provide users with a high-level interface for programming data parallel scientific applications, while delegating to the compiler/runtime system the task of generating explicitly parallel message-passing programs. We begin by providing a short overview of the HPF language. This is followed by a detailed discussion of the efficient use of HPF for applications involving multiple structured grids such as multiblock and adaptive mesh refinement (AMR) codes as well as unstructured grid codes. We focus on the data structures and computational structures used in these codes and on the high-level strategies that can be expressed in HPF to optimally exploit the parallelism in these algorithms.

  2. Comparative Simulation Studies of Multipacting in Higher-Order-Mode Couplers of Superconducting RF Cavities

    SciTech Connect

    Li, Y. M.; Liu, Kexin; Geng, Rongli

    2014-02-01

    Multipacting (MP) in higher-order-mode (HOM) couplers of the International Linear Collider (ILC) baseline cavity and the Continuous Electron Beam Accelerator Facility (CEBAF) 12 GeV upgrade cavity is studied by using the ACE3P suites, developed by the Advanced Computations Department at SLAC. For the ILC cavity HOM coupler, the simulation results show that resonant trajectories exist in three zones, corresponding to an accelerating gradient range of 0.6-1.6 MV/m, 21-34 MV/m, 32-35 MV/m, and > 40MV/m, respectively. For the CEBAF 12 GeV upgrade cavity HOM coupler, resonant trajectories exist in one zone, corresponding to an accelerating gradient range of 6-13 MV/m. Potential implications of these MP barriers are discussed in the context of future high energy pulsed as well as medium energy continuous wave (CW) accelerators based on superconducting radio frequency cavities. Frequency scaling of MP's predicted in HOM couplers of the ILC, CBEAF upgrade, SNS and FLASH third harmonic cavity is given and found to be in good agreement with the analytical result based on the parallel plate model.

  3. Time-Domain Simulation of RF Couplers

    SciTech Connect

    Smithe, David; Carlsson, Johan; Austin, Travis

    2009-11-26

    We have developed a finite-difference time-domain (FDTD) fluid-like approach to integrated plasma-and-coupler simulation [1], and show how it can be used to model LH and ICRF couplers in the MST and larger tokamaks.[2] This approach permits very accurate 3-D representation of coupler geometry, and easily includes non-axi-symmetry in vessel wall, magnetic equilibrium, and plasma density. The plasma is integrated with the FDTD Maxwell solver in an implicit solve that steps over electron time-scales, and permits tenuous plasma in the coupler itself, without any need to distinguish or interface between different regions of vacuum and/or plasma. The FDTD algorithm is also generalized to incorporate a time-domain sheath potential [3] on metal structures within the simulation, to look for situations where the sheath potential might generate local sputtering opportunities. Benchmarking of the time-domain sheath algorithm has been reported in the references. Finally, the time-domain software [4] permits the use of particles, either as field diagnostic (test particles) or to self-consistently compute plasma current from the applied RF power.

  4. Nonlinear multimode interference coupler for biological sensing

    NASA Astrophysics Data System (ADS)

    Tajaddini, Mehdi; Mat Jafri, Mohd Zubir

    2013-06-01

    In this study, we propose an all optical sensor based on nonlinearity in a multimode interference coupler. The sensor can be tuned to highest sensitivity in the refractive index ranges sufficient to detect protein- based molecules or other water- soluble chemical or biological materials. The nonlinear regimes show the capability to operate on any choice of materials for slab waveguide even conventional glass. The Kerr nonlinear effect is considered as the nonlinear effect for third order nonlinearity materials; this effect is studied in the multimode waveguide with MPA method that promises to investigate the coupler in small lengths. The visible changes of field profile at output facet in various surrounding layer refractive index show the high sensitivity to the refractive index of surrounding layer that is foundation of introducing a sensor. Also, the result show the high distinguished changes on output intensity in various refractive index of surrounding layer even in conventional glass as a chosen material for coupler. To the best of our knowledge this is the first time that a nonlinear MMI in a few micrometers is proposed as a robustness sensor. In fact, this paper brings a useful and powerful way to progress the all optical sensors based on MMI couplers.

  5. High Performance Thin Layer Chromatography.

    ERIC Educational Resources Information Center

    Costanzo, Samuel J.

    1984-01-01

    Clarifies where in the scheme of modern chromatography high performance thin layer chromatography (TLC) fits and why in some situations it is a viable alternative to gas and high performance liquid chromatography. New TLC plates, sample applications, plate development, and instrumental techniques are considered. (JN)

  6. Poisson's ratio of high-performance concrete

    SciTech Connect

    Persson, B.

    1999-10-01

    This article outlines an experimental and numerical study on Poisson's ratio of high-performance concrete subjected to air or sealed curing. Eight qualities of concrete (about 100 cylinders and 900 cubes) were studied, both young and in the mature state. The concretes contained between 5 and 10% silica fume, and two concretes in addition contained air-entrainment. Parallel studies of strength and internal relative humidity were carried out. The results indicate that Poisson's ratio of high-performance concrete is slightly smaller than that of normal-strength concrete. Analyses of the influence of maturity, type of aggregate, and moisture on Poisson's ratio are also presented. The project was carried out from 1991 to 1998.

  7. (abstract) The Design of a Benign Fail-safe Mechanism Using a Low-melting-point Metal Alloy Coupler

    NASA Technical Reports Server (NTRS)

    Blomquist, Richard S.

    1995-01-01

    Because the alpha proton X ray spectrometer (APXS) sensor head on the Mars Pathfinder rover, Sojourner, is placed on Martian soil by the deployment mechanism (ADM), the rover would be crippled if the actuator fails when the mechanism is in its deployed position, as rover ground clearance is then reduced to zero. This paper describes the unique fail-safe mounted on the ADM, especially the use of a low-temperature-melting alloy as a coupler device. The final form of the design is a low-melting-point metal pellet coupler, made from Cerrobend, in parallel with a Negator spring pack. In its solid state, the metal rigidly connects the driver (the actuator) and the driven part (the mechanism). When commanded, a strip heater wrapped around the coupler melts the metal pellet (at 60(deg)C), allowing the driven part to turn independent of the driver. The Negator spring retracts the mechanism to its fully stowed position. This concept meets all the design criteria, and provides an added benefit. When the metal hardens the coupler once again rigidly connects the actuator and the mechanism. The concept presented here can easily be applied to other applications. Anywhere release devices are needed, low-melting-point couplers can be considered. The issues to be concerned with are thermal isolation, proper setting of the parts before actuation, and possible outgassing concerns. However, when these issues are overcome, the resulting release mechanism can promise to be the most light, simple, power conserving alternative available.

  8. Climate Modeling using High-Performance Computing

    SciTech Connect

    Mirin, A A

    2007-02-05

    The Center for Applied Scientific Computing (CASC) and the LLNL Climate and Carbon Science Group of Energy and Environment (E and E) are working together to improve predictions of future climate by applying the best available computational methods and computer resources to this problem. Over the last decade, researchers at the Lawrence Livermore National Laboratory (LLNL) have developed a number of climate models that provide state-of-the-art simulations on a wide variety of massively parallel computers. We are now developing and applying a second generation of high-performance climate models. Through the addition of relevant physical processes, we are developing an earth systems modeling capability as well.

  9. Optical Nonreciprocity in Asymmetric Optomechanical Couplers

    NASA Astrophysics Data System (ADS)

    Wang, Zheqi; Shi, Lei; Liu, Yi; Xu, Xinbiao; Zhang, Xinliang

    2015-03-01

    We propose an all-optical integrated nonreciprocal device on the optomechanical platform with a large nonreciprocal bandwidth and low operating power. The device is based on an asymmetric silicon coupler consisting of two branches. One of them is a conventional strip waveguide fixed on the substrate, and the other is a freestanding nanostring suspended above a groove in the substrate. When light is launched into the coupler, the optical gradient force between the freestanding nanostring and the underlying substrate leads to the deflection of the nanostring, and finally results in destruction of the initial phase-matching condition between the two branches. The suspended branch would achieve distinct deflections when light is incident from different ports. The simulation results show a nonreciprocal bandwidth of 13.1 nm with operating power of 390 μW. With the advantages of simple structure, low power consumption and large operating bandwidth, our work provides a promising solution for on-chip passive nonreciprocal device.

  10. Folded waveguide cavity coupler for ICRF heating

    SciTech Connect

    Owens, T.L.

    1986-01-01

    This paper introduces a new type of waveguide coupler for ion cyclotron range of frequencies (ICRF) heating which is an adaptation of a concept known as a ''folded waveguide'' reported by Barrow and Schaevitz in connection with low-frequency waveguide transmission systems. The basic idea involves ''folding'' a simple rectangular waveguide to form a more compact structure. Cutoff for the folded waveguide occurs when one-half of a free-space wavelength equals the path length around the ''folds'' of the structure. By adding a large number of folds, the path length around the folds can be made large, leading to very low cutoff frequencies relative to those for simple rectangular waveguides having comparable outside dimensions. Folded waveguide couplers are practical for frequencies as low as 60 MHz for some ports found on present-day experients.

  11. Fundamental Power Couplers for Superconducting Cavities

    SciTech Connect

    Isidoro E. Campisi

    2001-09-01

    Fundamental power couplers (FPC's) for superconducting cavities must meet very strict requirements to perform at high power levels (hundreds of kilowatts) and in a variety of conditions (CS, pulsed, travelling wave, standing wave) without adversely affecting the performance of the cavities they are powering. Producing good coupler designs and achieving operational performances in accelerator environments are challenging tasks that have traditionally involved large resources from many laboratories. The designs involve state-of-the-art activities in RF, cryogenic and mechanical engineering, materials science, vacuum technology, and electromagnetic field modeling. Handling, assembly and conditioning procedures have been developed to achieve ever-increasing power levels and more reliable operation. In this paper, the technical issues associated with the design, construction, assembly, processing, and operation of FPC's will be reviewed, together with the progress in FPC activities in several laboratories during the past few years.

  12. Optically controlled quadrature coupler on silicon substrate

    NASA Astrophysics Data System (ADS)

    Bhadauria, Avanish; Sharma, Sonia; Sonania, Shikha; Akhtar, Jamil

    2016-03-01

    In this paper, we have proposed and studied an optically controlled quadrature coupler fabricated on silicon substrate. The optically controlled quadrature coupler can be realized by terminating its coupled or through ports by optically induced load. Simulation and experimental results show that by varying optical intensity, we can control the phase and amplitude of output RF signal and can realize optically controlled reflection type attenuator, reflection type phase-shifter and ultrafast switches. The new kind of proposed device can be useful for ultra-fast signal processing and modulation schemes in high speed communication especially in QPSK modulation. The optical control has several advantages over conventional techniques such as MEMS and other semiconductor switching, which have several inherent disadvantages and limitations like low response time, low power handling capacity, device parasitic and non-linearity.

  13. Cryostat for testing RF power couplers

    SciTech Connect

    Kuchnir, M.; Champion, M.S.; Koepke, K.P.; Misek, J.R.

    1996-03-01

    Similar to the power leads of accelerator superconducting magnets, the power couplers of accelerator superconducting cavities are components that link room temperature to superfluid helium temperature for the purpose of energy transfer. Instead of conducting kiloamperes of current they guide megawatts of RF power between those two temperatures. In this paper we describe a cryostat designed for testing the performance of these components and measuring their heat loads. A special feature of this cryostat is its minimum liquid inventory that considerably simplifies safety related requirements. This cryostat is part of a Fermilab facility contributing to the international collaboration working on TESLA (TeV Electron Superconducting Linear Accelerator). This facility is now operational and we will be presenting specifications as well as performance data on the cryostat as well as the first pair of power couplers tested with it.

  14. Tough high performance composite matrix

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H. (Inventor); Johnston, Norman J. (Inventor)

    1994-01-01

    This invention is a semi-interpentrating polymer network which includes a high performance thermosetting polyimide having a nadic end group acting as a crosslinking site and a high performance linear thermoplastic polyimide. Provided is an improved high temperature matrix resin which is capable of performing in the 200 to 300 C range. This resin has significantly improved toughness and microcracking resistance, excellent processability, mechanical performance, and moisture and solvent resistances.

  15. Integrated-optical directional coupler biosensor

    NASA Astrophysics Data System (ADS)

    Luff, B. J.; Harris, R. D.; Wilkinson, J. S.; Wilson, R.; Schiffrin, D. J.

    1996-04-01

    We present measurements of biomolecular binding reactions, using a new type of integrated-optical biosensor based on a planar directional coupler structure. The device is fabricated by Ag+ - Na+ ion exchange in glass, and definition of the sensing region is achieved by use of transparent fluoropolymer isolation layers formed by thermal evaporation. The suitability of the sensor for application to the detection of environmental pollutants is considered.

  16. High Power Co-Axial Coupler

    SciTech Connect

    Johnson, Rolland; Neubauer, Michael

    2013-08-14

    A superconducting RF (SRF) power coupler capable of handling 500 kW CW RF power at 750 MHz is required for present and future storage rings and linacs. There are over 35 coupler designs for SRF cavities ranging in frequency from 325 to 1500 MHz. Coupler windows vary from cylinders to cones to disks and RF power couplers will always be limited by the ability of ceramic windows and their matching systems to withstand the stresses due to non-uniform heating from dielectric and wall losses, multipactor, and mechanical flexure. In the Phase II project, we built a double window coaxial system with materials that would not otherwise be useable due to individual VSWRs. Double window systems can be operated such that one is cold (LN2) and one is warm. They can have different materials and still have a good match without using matching elements that create problematic multipactor bands. The match of the two windows will always result from the cancellation of the two window’s reflections when they are located approximately a quarter wavelength apart or multiples of a quarter wavelength. The window assemblies were carefully constructed to put the window material and its braze joint in compression at all times. This was done using explosion bonding techniques which allow for inexpensive fabrication of the vacuum / compression ring out of stainless steel with copper plating applied to the inner surface. The EIA 3-1/8” double window assembly was then successfully baked out and tested to 12 kW in a 3-1/8” co-axial system. The thermal gradient across the window was measured to be 90 C which represents about 15 ksi tensile stress in an uncompressed window. In our design the compression was calculated to be about 25 ksi, so the net compressive force was 5 ksi at full power.

  17. High Power Co-Axial SRF Coupler

    SciTech Connect

    M.L. Neubauer, R.A. Rimmer

    2009-05-01

    There are over 35 coupler designs for SRF cavities ranging in frequency from 325 to 1500 MHz. Two-thirds of these designs are coaxial couplers using disk or cylindrical ceramics in various combinations and configurations. While it is well known that dielectric losses go down by several orders of magnitude at cryogenic temperatures, it not well known that the thermal conductivity also goes down, and it is the ratio of thermal conductivity to loss tangent (SRF ceramic Quality Factor) and ceramic volume which will determine the heat load of any given design. We describe a novel robust co-axial SRF coupler design which uses compressed window technology. This technology will allow the use of highly thermally conductive materials for cryogenic windows. The mechanical designs will fit into standard-sized ConFlat® flanges for ease of assembly. Two windows will be used in a coaxial line. The distance between the windows is adjusted to cancel their reflections so that the same window can be used in many different applications at various frequencies.

  18. A Third Generation Lower Hybrid Coupler

    SciTech Connect

    S. Bernabei; J. Hosea; C. Kung; D. Loesser; J. Rushinski; J.R. Wilson; R. Parker

    2001-12-05

    The Princeton Plasma Physics Laboratory (PPPL) and the Massachusetts Institute of Technology (MIT) are preparing an experiment of current profile control using lower-hybrid waves in order to produce and sustain advanced tokamak regimes in steady-state conditions in Alcator C-Mod. Unlike JET's, ToreSupra's and JT60's couplers, the C-Mod lower-hybrid coupler does not employ the now conventional multijunction design, but will have similar characteristics, compactness, and internal power division while retaining full control of the antenna element phasing. This is achieved by using 3 dB vertical power splitters and a stack of laminated plates with the waveguides milled in them. Construction is simplified and allows easy control and maintenance of all parts. Many precautions are taken to avoid arcing. Special care is also taken to avoid the recycling of reflected power which could affect the coupling and the launched n(subscript ||) spectrum. The results from C-Mod should allow further simplification in the designs of the coupler planned for KSTAR (Korea Superconducting Tokamak Advanced Research) and ITER (International Thermonuclear Experimental Reactor).

  19. RISC Processors and High Performance Computing

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    In this tutorial, we will discuss top five current RISC microprocessors: The IBM Power2, which is used in the IBM RS6000/590 workstation and in the IBM SP2 parallel supercomputer, the DEC Alpha, which is in the DEC Alpha workstation and in the Cray T3D; the MIPS R8000, which is used in the SGI Power Challenge; the HP PA-RISC 7100, which is used in the HP 700 series workstations and in the Convex Exemplar; and the Cray proprietary processor, which is used in the new Cray J916. The architecture of these microprocessors will first be presented. The effective performance of these processors will then be compared, both by citing standard benchmarks and also in the context of implementing a real applications. In the process, different programming models such as data parallel (CM Fortran and HPF) and message passing (PVM and MPI) will be introduced and compared. The latest NAS Parallel Benchmark (NPB) absolute performance and performance per dollar figures will be presented. The next generation of the NP13 will also be described. The tutorial will conclude with a discussion of general trends in the field of high performance computing, including likely future developments in hardware and software technology, and the relative roles of vector supercomputers tightly coupled parallel computers, and clusters of workstations. This tutorial will provide a unique cross-machine comparison not available elsewhere.

  20. Directional multimode coupler for planar magnonics: Side-coupled magnetic stripes

    NASA Astrophysics Data System (ADS)

    Sadovnikov, A. V.; Beginin, E. N.; Sheshukova, S. E.; Romanenko, D. V.; Sharaevskii, Yu. P.; Nikitov, S. A.

    2015-11-01

    We experimentally demonstrate spin waves coupling in two laterally adjacent magnetic stripes. By the means of Brillouin light scattering spectroscopy, we show that the coupling efficiency depends both on the magnonic waveguides' geometry and the characteristics of spin-wave modes. In particular, the lateral confinement of coupled yttrium-iron-garnet stripes enables the possibility of control over the spin-wave propagation characteristics. Numerical simulations (in time domain and frequency domain) reveal the nature of intermodal coupling between two magnonic stripes. The proposed topology of multimode magnonic coupler can be utilized as a building block for fabrication of integrated parallel functional and logic devices such as the frequency selective directional coupler or tunable splitter, enabling a number of potential applications for planar magnonics.

  1. A Ratiometric Wavelength Measurement Based on a Silicon-on-Insulator Directional Coupler Integrated Device

    PubMed Central

    Wang, Pengfei; Hatta, Agus Muhamad; Zhao, Haoyu; Zheng, Jie; Farrell, Gerald; Brambilla, Gilberto

    2015-01-01

    A ratiometric wavelength measurement based on a Silicon-on-Insulator (SOI) integrated device is proposed and designed, which consists of directional couplers acting as two edge filters with opposite spectral responses. The optimal separation distance between two parallel silicon waveguides and the interaction length of the directional coupler are designed to meet the desired spectral response by using local supermodes. The wavelength discrimination ability of the designed ratiometric structure is demonstrated by a beam propagation method numerically and then is verified experimentally. The experimental results have shown a general agreement with the theoretical models. The ratiometric wavelength system demonstrates a resolution of better than 50 pm at a wavelength around 1550 nm with ease of assembly and calibration. PMID:26343668

  2. A Ratiometric Wavelength Measurement Based on a Silicon-on-Insulator Directional Coupler Integrated Device.

    PubMed

    Wang, Pengfei; Hatta, Agus Muhamad; Zhao, Haoyu; Zheng, Jie; Farrell, Gerald; Brambilla, Gilberto

    2015-01-01

    A ratiometric wavelength measurement based on a Silicon-on-Insulator (SOI) integrated device is proposed and designed, which consists of directional couplers acting as two edge filters with opposite spectral responses. The optimal separation distance between two parallel silicon waveguides and the interaction length of the directional coupler are designed to meet the desired spectral response by using local supermodes. The wavelength discrimination ability of the designed ratiometric structure is demonstrated by a beam propagation method numerically and then is verified experimentally. The experimental results have shown a general agreement with the theoretical models. The ratiometric wavelength system demonstrates a resolution of better than 50 pm at a wavelength around 1550 nm with ease of assembly and calibration. PMID:26343668

  3. Directional multimode coupler for planar magnonics: Side-coupled magnetic stripes

    SciTech Connect

    Sadovnikov, A. V. Nikitov, S. A.; Beginin, E. N.; Sheshukova, S. E.; Romanenko, D. V.; Sharaevskii, Yu. P.

    2015-11-16

    We experimentally demonstrate spin waves coupling in two laterally adjacent magnetic stripes. By the means of Brillouin light scattering spectroscopy, we show that the coupling efficiency depends both on the magnonic waveguides' geometry and the characteristics of spin-wave modes. In particular, the lateral confinement of coupled yttrium-iron-garnet stripes enables the possibility of control over the spin-wave propagation characteristics. Numerical simulations (in time domain and frequency domain) reveal the nature of intermodal coupling between two magnonic stripes. The proposed topology of multimode magnonic coupler can be utilized as a building block for fabrication of integrated parallel functional and logic devices such as the frequency selective directional coupler or tunable splitter, enabling a number of potential applications for planar magnonics.

  4. High-performance parallel interface to synchronous optical network gateway

    DOEpatents

    St. John, Wallace B.; DuBois, David H.

    1998-08-11

    A digital system provides sending and receiving gateways for HIPPI interfaces. Electronic logic circuitry formats data signals and overhead signals in a data frame that is suitable for transmission over a connecting fiber optic link. Multiplexers route the data and overhead signals to a framer module. The framer module allocates the data and overhead signals to a plurality of 9-byte words that are arranged in a selected protocol. The formatted words are stored in a storage register for output through the gateway.

  5. RF Processing of the Couplers for the SNS Superconducting Cavities

    SciTech Connect

    Y.Kang; I.E. Campisi; D. Stout; A. Vassioutchenko; M. Stirbet; M. Drury; T. Powers

    2005-07-10

    All eighty-one fundamental power couplers for the 805 MHz superconducting cavities of the SNS linac have been RF conditioned and installed in the cryomodules successfully. The couplers were RF processed at JLAB or at the SNS in ORNL: more than forty couplers have been RF conditioned in the SNS RF Test Facility (RFTF) after the first forty couplers were conditioned at JLAB. The couplers were conditioned up to 650 kW forward power at 8% duty cycle in traveling and standing waves. They were installed on the cavities in the cryomodules and then assembled with the airside waveguide transitions. The couplers have been high power RF tested with satisfactory accelerating field gradients in the cooled cavities.

  6. A compact RF power coupler for the NLC linac

    SciTech Connect

    Bowden, G.B.

    2000-03-01

    A high power RF coupler connecting WR90 rectangular waveguide to the disc loaded waveguide accelerating structure of NLC is described. The coupler design is symmetric and free of beam deflecting field components. It makes an efficient electrical match between the rectangular waveguide power feed and the accelerator structure while keeping electrical surface field enhancement low. Electrical and mechanical design of the coupler are presented as well as quantitative comparisons between numerical simulation and low power cold test models.

  7. Improved input and output couplers for SC acceleration structure

    SciTech Connect

    Solyak, N.; Gonin, I.; Latina, A.; Lunin, A.; Poloubotko, V.; Yakovlev, V.; /Fermilab

    2009-04-01

    Different couplers are described that allow the reduction of both transverse wake potential and RF kick in the SC acceleration structure of ILC. A simple rotation of the couplers reducing the RF kick and transverse wake kick is discussed for both the main linac and bunch compressors, along with possible limitations of this method. Designs of a coupler unit are presented which preserve axial symmetry of the structure, and provide reduced both the RF kick and transverse wake field.

  8. Application of commercial star couplers to increase signal dynamic range

    SciTech Connect

    Whitcomb, B.M.; Smiley, V.N.; Flurer, R.L.; Nelson, L.K.

    1984-01-01

    Fused biconical tapered (FBT) fiber optic star couplers have been used in a variety of applications at the Nevada Test Site (NTS) in several diagnostic experiments to provide increased dynamic range for the recording devices or to divide the available signal between different recording devices. A number of installation problems have been manifested in this application of FBT couplers. The most severe problem results from the modal selection mechanism inherent in the design of FBT couplers. Substantial work has been done to characterize a variety of commercial couplers for this application.

  9. INL High Performance Building Strategy

    SciTech Connect

    Jennifer D. Morton

    2010-02-01

    High performance buildings, also known as sustainable buildings and green buildings, are resource efficient structures that minimize the impact on the environment by using less energy and water, reduce solid waste and pollutants, and limit the depletion of natural resources while also providing a thermally and visually comfortable working environment that increases productivity for building occupants. As Idaho National Laboratory (INL) becomes the nation’s premier nuclear energy research laboratory, the physical infrastructure will be established to help accomplish this mission. This infrastructure, particularly the buildings, should incorporate high performance sustainable design features in order to be environmentally responsible and reflect an image of progressiveness and innovation to the public and prospective employees. Additionally, INL is a large consumer of energy that contributes to both carbon emissions and resource inefficiency. In the current climate of rising energy prices and political pressure for carbon reduction, this guide will help new construction project teams to design facilities that are sustainable and reduce energy costs, thereby reducing carbon emissions. With these concerns in mind, the recommendations described in the INL High Performance Building Strategy (previously called the INL Green Building Strategy) are intended to form the INL foundation for high performance building standards. This revised strategy incorporates the latest federal and DOE orders (Executive Order [EO] 13514, “Federal Leadership in Environmental, Energy, and Economic Performance” [2009], EO 13423, “Strengthening Federal Environmental, Energy, and Transportation Management” [2007], and DOE Order 430.2B, “Departmental Energy, Renewable Energy, and Transportation Management” [2008]), the latest guidelines, trends, and observations in high performance building construction, and the latest changes to the Leadership in Energy and Environmental Design

  10. High-performance membrane chromatography.

    PubMed

    Belenkii, B G; Malt'sev, V G

    1995-02-01

    In gradient chromatography for proteins migrating along the chromatographic column, the critical distance X0 has been shown to exist at which the separation of zones is at a maximum and band spreading is at a minimum. With steep gradients and small elution velocity, the column length may be reduced to the level of membrane thickness--about one millimeter. The peculiarities of this novel separation method for proteins, high-performance membrane chromatography (HPMC), are discussed and stepwise elution is shown to be especially effective. HPMC combines the advantages of membrane technology and high-performance liquid chromatography, and avoids their drawbacks. PMID:7727132

  11. High Performance Photovoltaic Project Overview

    SciTech Connect

    Symko-Davies, M.; McConnell, R.

    2005-01-01

    The High-Performance Photovoltaic (HiPerf PV) Project was initiated by the U.S. Department of Energy to substantially increase the viability of photovoltaics (PV) for cost-competitive applications so that PV can contribute significantly to our energy supply and environment in the 21st century. To accomplish this, the National Center for Photovoltaics (NCPV) directs in-house and subcontracted research in high-performance polycrystalline thin-film and multijunction concentrator devices. In this paper, we describe the recent research accomplishments in the in-house directed efforts and the research efforts under way in the subcontracted area.

  12. High performance flexible heat pipes

    NASA Technical Reports Server (NTRS)

    Shaubach, R. M.; Gernert, N. J.

    1985-01-01

    A Phase I SBIR NASA program for developing and demonstrating high-performance flexible heat pipes for use in the thermal management of spacecraft is examined. The program combines several technologies such as flexible screen arteries and high-performance circumferential distribution wicks within an envelope which is flexible in the adiabatic heat transport zone. The first six months of work during which the Phase I contract goal were met, are described. Consideration is given to the heat-pipe performance requirements. A preliminary evaluation shows that the power requirement for Phase II of the program is 30.5 kilowatt meters at an operating temperature from 0 to 100 C.

  13. The path toward HEP High Performance Computing

    NASA Astrophysics Data System (ADS)

    Apostolakis, John; Brun, René; Carminati, Federico; Gheata, Andrei; Wenzel, Sandro

    2014-06-01

    High Energy Physics code has been known for making poor use of high performance computing architectures. Efforts in optimising HEP code on vector and RISC architectures have yield limited results and recent studies have shown that, on modern architectures, it achieves a performance between 10% and 50% of the peak one. Although several successful attempts have been made to port selected codes on GPUs, no major HEP code suite has a "High Performance" implementation. With LHC undergoing a major upgrade and a number of challenging experiments on the drawing board, HEP cannot any longer neglect the less-than-optimal performance of its code and it has to try making the best usage of the hardware. This activity is one of the foci of the SFT group at CERN, which hosts, among others, the Root and Geant4 project. The activity of the experiments is shared and coordinated via a Concurrency Forum, where the experience in optimising HEP code is presented and discussed. Another activity is the Geant-V project, centred on the development of a highperformance prototype for particle transport. Achieving a good concurrency level on the emerging parallel architectures without a complete redesign of the framework can only be done by parallelizing at event level, or with a much larger effort at track level. Apart the shareable data structures, this typically implies a multiplication factor in terms of memory consumption compared to the single threaded version, together with sub-optimal handling of event processing tails. Besides this, the low level instruction pipelining of modern processors cannot be used efficiently to speedup the program. We have implemented a framework that allows scheduling vectors of particles to an arbitrary number of computing resources in a fine grain parallel approach. The talk will review the current optimisation activities within the SFT group with a particular emphasis on the development perspectives towards a simulation framework able to profit best from

  14. Panelized high performance multilayer insulation

    NASA Technical Reports Server (NTRS)

    Burkley, R. A.; Shriver, C. B.; Stuckey, J. M.

    1968-01-01

    Multilayer insulation coverings with low conductivity foam spacers are interleaved with quarter mil aluminized polymer film radiation shields to cover flight type liquid hydrogen tankage of space vehicles with a removable, structurally compatible, lightweight, high performance cryogenic insulation capable of surviving extended space mission environments.

  15. High performance rolling element bearing

    NASA Technical Reports Server (NTRS)

    Bursey, Jr., Roger W. (Inventor); Olinger, Jr., John B. (Inventor); Owen, Samuel S. (Inventor); Poole, William E. (Inventor); Haluck, David A. (Inventor)

    1993-01-01

    A high performance rolling element bearing (5) which is particularly suitable for use in a cryogenically cooled environment, comprises a composite cage (45) formed from glass fibers disposed in a solid lubricant matrix of a fluorocarbon polymer. The cage includes inserts (50) formed from a mixture of a soft metal and a solid lubricant such as a fluorocarbon polymer.

  16. High Performance Bulk Thermoelectric Materials

    SciTech Connect

    Ren, Zhifeng

    2013-03-31

    Over 13 plus years, we have carried out research on electron pairing symmetry of superconductors, growth and their field emission property studies on carbon nanotubes and semiconducting nanowires, high performance thermoelectric materials and other interesting materials. As a result of the research, we have published 104 papers, have educated six undergraduate students, twenty graduate students, nine postdocs, nine visitors, and one technician.

  17. Mode selective directional coupler for NLC

    SciTech Connect

    Tantawi, S.G.

    1994-10-01

    The design method for a high power, X-band, 50 dB, circular to rectangular directional coupler is presented. The circular guide is over moded and is intended to operate in TE{sub 01} mode. The rectangular guide operates at the fundamental TE{sub 10} mode. A small percentage of higher order modes in the circular guide can cause considerable errors in the measurements because the magnitude of the axial magnetic field of these modes is higher than that of the operating mode, especially near their cutoff. We used a Hamming window patten for the coupling slots to achieve mode selectivity. Comparison of theory and experiment will be presented.

  18. 49 CFR 179.14 - Coupler vertical restraint system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... material failure, vertical loads of at least 200,000 pounds (90,718.5 kg) applied in upward and downward... mating coupler (or simulated coupler) having only frictional vertical force resistance at the mating... section. A test is successful when a vertical disengagement or material failure does not occur during...

  19. An Over-moded Fundamental Power Coupler for the ILC

    SciTech Connect

    Jeff Neilson

    2009-05-20

    The current design of fundamental power couplers for the ILC are expensive and require excessively long conditioning times. The goal of this develoment is design of a coupler that requires little rf processing and is significantly less expensive to build than the present ILC coupler. The goal of this program is development of a new technology for power couplers.This new technology is based on the cylindrical TE01 mode and other over-moded technologies developed for the X-band rf distribution system of the NCLTA. During the Phase I program, a TE10 to TE01 mode transducer suitable for use as a part of a power coupler in the ILC will be designed, built and tested. Following a succesful test, prototype designs of the TE01 to cavity coupler and thermal will be produced. A detailed study of the suitability of this overmoded waveguide technology for the ILC power coupler will be provided in the final report. Development of over-moded power couplers for superconducting cavities could find application im many world-wide accelerator projects, such as SNS, Jefferson Lab upgrade, RIA, TESLA in addition to the ILC.

  20. 30 CFR 75.1405-1 - Automatic couplers, haulage equipment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Automatic couplers, haulage equipment. 75.1405-1 Section 75.1405-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Hoisting and Mantrips § 75.1405-1 Automatic couplers, haulage...

  1. 30 CFR 75.1405-1 - Automatic couplers, haulage equipment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic couplers, haulage equipment. 75.1405-1 Section 75.1405-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Hoisting and Mantrips § 75.1405-1 Automatic couplers, haulage...

  2. 30 CFR 75.1405-1 - Automatic couplers, haulage equipment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Automatic couplers, haulage equipment. 75.1405-1 Section 75.1405-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Hoisting and Mantrips § 75.1405-1 Automatic couplers, haulage...

  3. 30 CFR 75.1405-1 - Automatic couplers, haulage equipment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Automatic couplers, haulage equipment. 75.1405-1 Section 75.1405-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Hoisting and Mantrips § 75.1405-1 Automatic couplers, haulage...

  4. 30 CFR 75.1405-1 - Automatic couplers, haulage equipment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Automatic couplers, haulage equipment. 75.1405-1 Section 75.1405-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Hoisting and Mantrips § 75.1405-1 Automatic couplers, haulage...

  5. TTF3 power coupler thermal analysis for LCLS-II CW operation

    SciTech Connect

    Xiao, L.; Adolphsen, C.; Li, Z.; Nantista, C.; Raubenheimer, T.; Solyak, N.; Gonin, I.

    2015-05-13

    The TESLA 9-cell SRF cavity design has been adopted for use in the LCLS-II SRF Linac. Its TTF3 coaxial fundamental power coupler (FPC), optimized for pulsed operation in European XFEL and ILC, requires modest changes to make it suitable for LCLS-II continuous-wave (CW) operation. For LCLS-II it must handle up to 7 kW of power, fully reflected, with the maximum temperature around 450 K, the coupler bake temperature. In order to improve TTF3 FPC cooling, an increased copper plating thickness will be used on the inner conductor of the ‘warm’ section of the coupler. Also, the antenna will be shortened to achieve higher cavity Qext values. Fully 3D FPC thermal analysis has been performed using the SLAC-developed parallel finite element code suite ACE3P, which includes electromagnetic codes and an integrated electromagnetic, thermal and mechanical multi-physics code. In this paper, we present TTF3 FPC thermal analysis simulation results obtained using ACE3P as well as a comparison with measurement results.

  6. High performance bilateral telerobot control.

    PubMed

    Kline-Schoder, Robert; Finger, William; Hogan, Neville

    2002-01-01

    Telerobotic systems are used when the environment that requires manipulation is not easily accessible to humans, as in space, remote, hazardous, or microscopic applications or to extend the capabilities of an operator by scaling motions and forces. The Creare control algorithm and software is an enabling technology that makes possible guaranteed stability and high performance for force-feedback telerobots. We have developed the necessary theory, structure, and software design required to implement high performance telerobot systems with time delay. This includes controllers for the master and slave manipulators, the manipulator servo levels, the communication link, and impedance shaping modules. We verified the performance using both bench top hardware as well as a commercial microsurgery system. PMID:15458092

  7. High performance dielectric materials development

    NASA Technical Reports Server (NTRS)

    Piche, Joe; Kirchner, Ted; Jayaraj, K.

    1994-01-01

    The mission of polymer composites materials technology is to develop materials and processing technology to meet DoD and commercial needs. The following are outlined in this presentation: high performance capacitors, high temperature aerospace insulation, rationale for choosing Foster-Miller (the reporting industry), the approach to the development and evaluation of high temperature insulation materials, and the requirements/evaluation parameters. Supporting tables and diagrams are included.

  8. High performance ammonium nitrate propellant

    NASA Technical Reports Server (NTRS)

    Anderson, F. A. (Inventor)

    1979-01-01

    A high performance propellant having greatly reduced hydrogen chloride emission is presented. It is comprised of: (1) a minor amount of hydrocarbon binder (10-15%), (2) at least 85% solids including ammonium nitrate as the primary oxidizer (about 40% to 70%), (3) a significant amount (5-25%) powdered metal fuel, such as aluminum, (4) a small amount (5-25%) of ammonium perchlorate as a supplementary oxidizer, and (5) optionally a small amount (0-20%) of a nitramine.

  9. New, high performance rotating parachute

    SciTech Connect

    Pepper, W.B. Jr.

    1983-01-01

    A new rotating parachute has been designed primarily for recovery of high performance reentry vehicles. Design and development/testing results are presented from low-speed wind tunnel testing, free-flight deployments at transonic speeds and tests in a supersonic wind tunnel at Mach 2.0. Drag coefficients of 1.15 based on the 2-ft diameter of the rotor have been measured in the wind tunnel. Stability of the rotor is excellent.

  10. New HOM coupler design for high current SRF cavity

    SciTech Connect

    Xu, W.; Ben-Zvi, I.; Belomestnykh, S.; Hahn, H.; Johnson, E.

    2011-03-28

    Damping higher order modes (HOMs) significantly to avoid beam instability is a challenge for the high current Energy Recovery Linac-based eRHIC at BNL. To avoid the overheating effect and high tuning sensitivity, current, a new band-stop HOM coupler is being designed at BNL. The new HOM coupler has a bandwidth of tens of MHz to reject the fundamental mode, which will avoid overheating due to fundamental frequency shifting because of cooling down. In addition, the S21 parameter of the band-pass filter is nearly flat from first higher order mode to 5 times the fundamental frequency. The simulation results showed that the new couplers effectively damp HOMs for the eRHIC cavity with enlarged beam tube diameter and 2 120{sup o} HOM couplers at each side of cavity. This paper presents the design of HOM coupler, HOM damping capacity for eRHIC cavity and prototype test results.

  11. Omnidirectional spin-wave nanograting coupler.

    PubMed

    Yu, Haiming; Duerr, G; Huber, R; Bahr, M; Schwarze, T; Brandl, F; Grundler, D

    2013-01-01

    Magnonics as an emerging nanotechnology offers functionalities beyond current semiconductor technology. Spin waves used in cellular nonlinear networks are expected to speed up technologically, demanding tasks such as image processing and speech recognition at low power consumption. However, efficient coupling to microelectronics poses a vital challenge. Previously developed techniques for spin-wave excitation (for example, by using parametric pumping in a cavity) may not allow for the relevant downscaling or provide only individual point-like sources. Here we demonstrate that a grating coupler of periodically nanostructured magnets provokes multidirectional emission of short-wavelength spin waves with giantly enhanced amplitude compared with a bare microwave antenna. Exploring the dependence on ferromagnetic materials, lattice constants and the applied magnetic field, we find the magnonic grating coupler to be more versatile compared with gratings in photonics and plasmonics. Our results allow one to convert, in particular, straight microwave antennas into omnidirectional emitters for short-wavelength spin waves, which are key to cellular nonlinear networks and integrated magnonics. PMID:24189978

  12. Omnidirectional spin-wave nanograting coupler

    NASA Astrophysics Data System (ADS)

    Yu, Haiming; Duerr, G.; Huber, R.; Bahr, M.; Schwarze, T.; Brandl, F.; Grundler, D.

    2013-11-01

    Magnonics as an emerging nanotechnology offers functionalities beyond current semiconductor technology. Spin waves used in cellular nonlinear networks are expected to speed up technologically, demanding tasks such as image processing and speech recognition at low power consumption. However, efficient coupling to microelectronics poses a vital challenge. Previously developed techniques for spin-wave excitation (for example, by using parametric pumping in a cavity) may not allow for the relevant downscaling or provide only individual point-like sources. Here we demonstrate that a grating coupler of periodically nanostructured magnets provokes multidirectional emission of short-wavelength spin waves with giantly enhanced amplitude compared with a bare microwave antenna. Exploring the dependence on ferromagnetic materials, lattice constants and the applied magnetic field, we find the magnonic grating coupler to be more versatile compared with gratings in photonics and plasmonics. Our results allow one to convert, in particular, straight microwave antennas into omnidirectional emitters for short-wavelength spin waves, which are key to cellular nonlinear networks and integrated magnonics.

  13. Optical nonreciprocity in asymmetric optomechanical couplers.

    PubMed

    Wang, Zheqi; Shi, Lei; Liu, Yi; Xu, Xinbiao; Zhang, Xinliang

    2015-01-01

    We propose an all-optical integrated nonreciprocal device on the optomechanical platform with a large nonreciprocal bandwidth and low operating power. The device is based on an asymmetric silicon coupler consisting of two branches. One of them is a conventional strip waveguide fixed on the substrate, and the other is a freestanding nanostring suspended above a groove in the substrate. When light is launched into the coupler, the optical gradient force between the freestanding nanostring and the underlying substrate leads to the deflection of the nanostring, and finally results in destruction of the initial phase-matching condition between the two branches. The suspended branch would achieve distinct deflections when light is incident from different ports. The simulation results show a nonreciprocal bandwidth of 13.1 nm with operating power of 390 μW. With the advantages of simple structure, low power consumption and large operating bandwidth, our work provides a promising solution for on-chip passive nonreciprocal device. PMID:25728978

  14. Omnidirectional spin-wave nanograting coupler

    PubMed Central

    Yu, Haiming; Duerr, G.; Huber, R.; Bahr, M.; Schwarze, T.; Brandl, F.; Grundler, D.

    2013-01-01

    Magnonics as an emerging nanotechnology offers functionalities beyond current semiconductor technology. Spin waves used in cellular nonlinear networks are expected to speed up technologically, demanding tasks such as image processing and speech recognition at low power consumption. However, efficient coupling to microelectronics poses a vital challenge. Previously developed techniques for spin-wave excitation (for example, by using parametric pumping in a cavity) may not allow for the relevant downscaling or provide only individual point-like sources. Here we demonstrate that a grating coupler of periodically nanostructured magnets provokes multidirectional emission of short-wavelength spin waves with giantly enhanced amplitude compared with a bare microwave antenna. Exploring the dependence on ferromagnetic materials, lattice constants and the applied magnetic field, we find the magnonic grating coupler to be more versatile compared with gratings in photonics and plasmonics. Our results allow one to convert, in particular, straight microwave antennas into omnidirectional emitters for short-wavelength spin waves, which are key to cellular nonlinear networks and integrated magnonics. PMID:24189978

  15. High Performance Database Management for Earth Sciences

    NASA Technical Reports Server (NTRS)

    Rishe, Naphtali; Barton, David; Urban, Frank; Chekmasov, Maxim; Martinez, Maria; Alvarez, Elms; Gutierrez, Martha; Pardo, Philippe

    1998-01-01

    The High Performance Database Research Center at Florida International University is completing the development of a highly parallel database system based on the semantic/object-oriented approach. This system provides exceptional usability and flexibility. It allows shorter application design and programming cycles and gives the user control via an intuitive information structure. It empowers the end-user to pose complex ad hoc decision support queries. Superior efficiency is provided through a high level of optimization, which is transparent to the user. Manifold reduction in storage size is allowed for many applications. This system allows for operability via internet browsers. The system will be used for the NASA Applications Center program to store remote sensing data, as well as for Earth Science applications.

  16. High performance computing applications in neurobiological research

    NASA Technical Reports Server (NTRS)

    Ross, Muriel D.; Cheng, Rei; Doshay, David G.; Linton, Samuel W.; Montgomery, Kevin; Parnas, Bruce R.

    1994-01-01

    The human nervous system is a massively parallel processor of information. The vast numbers of neurons, synapses and circuits is daunting to those seeking to understand the neural basis of consciousness and intellect. Pervading obstacles are lack of knowledge of the detailed, three-dimensional (3-D) organization of even a simple neural system and the paucity of large scale, biologically relevant computer simulations. We use high performance graphics workstations and supercomputers to study the 3-D organization of gravity sensors as a prototype architecture foreshadowing more complex systems. Scaled-down simulations run on a Silicon Graphics workstation and scale-up, three-dimensional versions run on the Cray Y-MP and CM5 supercomputers.

  17. Achieving high performance on the Intel Paragon

    SciTech Connect

    Greenberg, D.S.; Maccabe, B.; Riesen, R.; Wheat, S.; Womble, D.

    1993-11-01

    When presented with a new supercomputer most users will first ask {open_quotes}How much faster will my applications run?{close_quotes} and then add a fearful {open_quotes}How much effort will it take me to convert to the new machine?{close_quotes} This paper describes some lessons learned at Sandia while asking these questions about the new 1800+ node Intel Paragon. The authors conclude that the operating system is crucial to both achieving high performance and allowing easy conversion from previous parallel implementations to a new machine. Using the Sandia/UNM Operating System (SUNMOS) they were able to port a LU factorization of dense matrices from the nCUBE2 to the Paragon and achieve 92% scaled speed-up on 1024 nodes. Thus on a 44,000 by 44,000 matrix which had required over 10 hours on the previous machine, they completed in less than 1/2 hour at a rate of over 40 GFLOPS. Two keys to achieving such high performance were the small size of SUNMOS (less than 256 kbytes) and the ability to send large messages with very low overhead.

  18. High-performance computing in seismology

    SciTech Connect

    1996-09-01

    The scientific, technical, and economic importance of the issues discussed here presents a clear agenda for future research in computational seismology. In this way these problems will drive advances in high-performance computing in the field of seismology. There is a broad community that will benefit from this work, including the petroleum industry, research geophysicists, engineers concerned with seismic hazard mitigation, and governments charged with enforcing a comprehensive test ban treaty. These advances may also lead to new applications for seismological research. The recent application of high-resolution seismic imaging of the shallow subsurface for the environmental remediation industry is an example of this activity. This report makes the following recommendations: (1) focused efforts to develop validated documented software for seismological computations should be supported, with special emphasis on scalable algorithms for parallel processors; (2) the education of seismologists in high-performance computing technologies and methodologies should be improved; (3) collaborations between seismologists and computational scientists and engineers should be increased; (4) the infrastructure for archiving, disseminating, and processing large volumes of seismological data should be improved.

  19. High-Performance Thermoelectric Semiconductors

    NASA Technical Reports Server (NTRS)

    Fleurial, Jean-Pierre; Caillat, Thierry; Borshchevsky, Alexander

    1994-01-01

    Figures of merit almost double current state-of-art thermoelectric materials. IrSb3 is semiconductor found to exhibit exceptional thermoelectric properties. CoSb3 and RhSb3 have same skutterudite crystallographic structure as IrSb3, and exhibit exceptional transport properties expected to contribute to high thermoelectric performance. These three compounds form solid solutions. Combination of properties offers potential for development of new high-performance thermoelectric materials for more efficient thermoelectric power generators, coolers, and detectors.

  20. Automatic Energy Schemes for High Performance Applications

    SciTech Connect

    Sundriyal, Vaibhav

    2013-01-01

    Although high-performance computing traditionally focuses on the efficient execution of large-scale applications, both energy and power have become critical concerns when approaching exascale. Drastic increases in the power consumption of supercomputers affect significantly their operating costs and failure rates. In modern microprocessor architectures, equipped with dynamic voltage and frequency scaling (DVFS) and CPU clock modulation (throttling), the power consumption may be controlled in software. Additionally, network interconnect, such as Infiniband, may be exploited to maximize energy savings while the application performance loss and frequency switching overheads must be carefully balanced. This work first studies two important collective communication operations, all-to-all and allgather and proposes energy saving strategies on the per-call basis. Next, it targets point-to-point communications to group them into phases and apply frequency scaling to them to save energy by exploiting the architectural and communication stalls. Finally, it proposes an automatic runtime system which combines both collective and point-to-point communications into phases, and applies throttling to them apart from DVFS to maximize energy savings. The experimental results are presented for NAS parallel benchmark problems as well as for the realistic parallel electronic structure calculations performed by the widely used quantum chemistry package GAMESS. Close to the maximum energy savings were obtained with a substantially low performance loss on the given platform.

  1. High-performance computing in image registration

    NASA Astrophysics Data System (ADS)

    Zanin, Michele; Remondino, Fabio; Dalla Mura, Mauro

    2012-10-01

    Thanks to the recent technological advances, a large variety of image data is at our disposal with variable geometric, radiometric and temporal resolution. In many applications the processing of such images needs high performance computing techniques in order to deliver timely responses e.g. for rapid decisions or real-time actions. Thus, parallel or distributed computing methods, Digital Signal Processor (DSP) architectures, Graphical Processing Unit (GPU) programming and Field-Programmable Gate Array (FPGA) devices have become essential tools for the challenging issue of processing large amount of geo-data. The article focuses on the processing and registration of large datasets of terrestrial and aerial images for 3D reconstruction, diagnostic purposes and monitoring of the environment. For the image alignment procedure, sets of corresponding feature points need to be automatically extracted in order to successively compute the geometric transformation that aligns the data. The feature extraction and matching are ones of the most computationally demanding operations in the processing chain thus, a great degree of automation and speed is mandatory. The details of the implemented operations (named LARES) exploiting parallel architectures and GPU are thus presented. The innovative aspects of the implementation are (i) the effectiveness on a large variety of unorganized and complex datasets, (ii) capability to work with high-resolution images and (iii) the speed of the computations. Examples and comparisons with standard CPU processing are also reported and commented.

  2. Integrated dual-mode 3 dB power coupler based on tapered directional coupler

    PubMed Central

    Luo, Yuchan; Yu, Yu; Ye, Mengyuan; Sun, Chunlei; Zhang, Xinliang

    2016-01-01

    A dual-mode 3 dB power coupler based on silicon-on-insulator platform for mode division multiplexing system is proposed and demonstrated. The device, which consists of a tapered directional coupler and two output bend waveguides, has a 50:50 coupling ratio around the wavelength of 1550 nm for both fundamental and first order transverse magnetic (TM0 and TM1) modes. Based on asymmetrical tapered structure, a short common coupling length of ~15.2 μm for both modes is realized by optimizing the width of the tapered waveguide. The measured insertion loss for both modes is less than 0.7 dB. The crosstalks are about −14.3 dB for TM0 mode and −18.1 dB for TM1 mode. PMID:27002747

  3. Integrated dual-mode 3 dB power coupler based on tapered directional coupler.

    PubMed

    Luo, Yuchan; Yu, Yu; Ye, Mengyuan; Sun, Chunlei; Zhang, Xinliang

    2016-01-01

    A dual-mode 3 dB power coupler based on silicon-on-insulator platform for mode division multiplexing system is proposed and demonstrated. The device, which consists of a tapered directional coupler and two output bend waveguides, has a 50:50 coupling ratio around the wavelength of 1550 nm for both fundamental and first order transverse magnetic (TM0 and TM1) modes. Based on asymmetrical tapered structure, a short common coupling length of ~15.2 μm for both modes is realized by optimizing the width of the tapered waveguide. The measured insertion loss for both modes is less than 0.7 dB. The crosstalks are about -14.3 dB for TM0 mode and -18.1 dB for TM1 mode. PMID:27002747

  4. High temperature superconducting axial field magnetic coupler: realization and test

    NASA Astrophysics Data System (ADS)

    Belguerras, L.; Mezani, S.; Lubin, T.; Lévêque, J.; Rezzoug, A.

    2015-09-01

    Contactless torque transmission through a large airgap is required in some industrial applications in which hermetic isolation is necessary. This torque transmission usually uses magnetic couplers, whose dimension strongly depends on the airgap flux density. The use of high temperature superconducting (HTS) coils to create a strong magnetic field may constitute a solution to reduce the size of the coupler. It is also possible to use this coupler to replace a torque tube in transmitting the torque produced by a HTS motor to its load. This paper presents the detailed construction and tests of an axial field HTS magnetic coupler. Pancake coils have been manufactured from BSCCO tape and used in one rotor of the coupler. The second rotor is mainly composed of NdFeB permanent magnets. Several tests have been carried out showing that the constructed coupler is working properly. A 3D finite element (FE) model of the studied coupler has been developed. Airgap magnetic field and torque measurements have been carried out and compared to the FE results. It has been shown that the measured and the computed quantities are in satisfactory agreement.

  5. RF Input Power Couplers for High Current SRF Applications

    SciTech Connect

    Khan, V. F.; Anders, W.; Burrill, Andrew; Knobloch, Jens; Kugeler, Oliver; Neumann, Axel; Wang, Haipeng

    2014-12-01

    High current SRF technology is being explored in present day accelerator science. The bERLinPro project is presently being built at HZB to address the challenges involved in high current SRF machines with the goal of generating and accelerating a 100 mA electron beam to 50 MeV in continuous wave (cw) mode at 1.3 GHz. One of the main challenges in this project is that of handling the high input RF power required for the photo-injector as well as booster cavities where there is no energy recovery process. A high power co-axial input power coupler is being developed to be used for the photo-injector and booster cavities at the nominal beam current. The coupler is based on the KEK–cERL design and has been modified to minimise the penetration of the coupler tip in the beam pipe without compromising on beam-power coupling (Qext ~105). Herein we report on the RF design of the high power (115 kW per coupler, dual couplers per cavity) bERLinPro (BP) coupler along with initial results on thermal calculations. We summarise the RF conditioning of the TTF-III couplers (modified for cw operation) performed in the past at BESSY/HZB. A similar conditioning is envisaged in the near future for the low current SRF photo-injector and the bERLinPro main linac cryomodule.

  6. SISYPHUS: A high performance seismic inversion factory

    NASA Astrophysics Data System (ADS)

    Gokhberg, Alexey; Simutė, Saulė; Boehm, Christian; Fichtner, Andreas

    2016-04-01

    In the recent years the massively parallel high performance computers became the standard instruments for solving the forward and inverse problems in seismology. The respective software packages dedicated to forward and inverse waveform modelling specially designed for such computers (SPECFEM3D, SES3D) became mature and widely available. These packages achieve significant computational performance and provide researchers with an opportunity to solve problems of bigger size at higher resolution within a shorter time. However, a typical seismic inversion process contains various activities that are beyond the common solver functionality. They include management of information on seismic events and stations, 3D models, observed and synthetic seismograms, pre-processing of the observed signals, computation of misfits and adjoint sources, minimization of misfits, and process workflow management. These activities are time consuming, seldom sufficiently automated, and therefore represent a bottleneck that can substantially offset performance benefits provided by even the most powerful modern supercomputers. Furthermore, a typical system architecture of modern supercomputing platforms is oriented towards the maximum computational performance and provides limited standard facilities for automation of the supporting activities. We present a prototype solution that automates all aspects of the seismic inversion process and is tuned for the modern massively parallel high performance computing systems. We address several major aspects of the solution architecture, which include (1) design of an inversion state database for tracing all relevant aspects of the entire solution process, (2) design of an extensible workflow management framework, (3) integration with wave propagation solvers, (4) integration with optimization packages, (5) computation of misfits and adjoint sources, and (6) process monitoring. The inversion state database represents a hierarchical structure with

  7. Multiplexed Energy Coupler for Rotating Equipment

    NASA Technical Reports Server (NTRS)

    Zhao, Xiaoliang

    2011-01-01

    A multiplexing antenna assembly can efficiently couple AC signal/energy into, or out of, rotating equipment. The unit only passes AC energy while blocking DC energy. Concentric tubes that are sliced into multiple pieces are assembled together so that, when a piece from an outer tube aligns well with an inner tube piece, efficient energy coupling is achieved through a capacitive scheme. With N outer pieces and M inner pieces, an effective N x M combination can be achieved in a multiplexed manner. The energy coupler is non-contact, which is useful if isolation from rotating and stationary parts is required. Additionally, the innovation can operate in high temperatures. Applications include rotating structure sensing, non-contact energy transmission, etc.

  8. Problem analysis and new design of TESLA coupler

    SciTech Connect

    Sun, Ding

    1994-06-01

    Problem analysis of tested TESLA coupler shows that the microwave discharge is a possible problem. Two new designs are presented. During previous tests of TESLA input coupler (doorknob with cylindrical ceramic window) it was unable to continuously operate above 300--400 kW and a small area of the coupler (area A in Figure 1) where the metal doorknob and ceramic window are only 2 mm apart was coated with metal by unidentified mechanism. In order to understand the problem and help the following designs, it is necessary to analyze possible mechanisms for the problem.

  9. Linear and nonlinear Zeno effects in an optical coupler

    SciTech Connect

    Abdullaev, F. Kh.; Konotop, V. V.; Shchesnovich, V. S.

    2011-04-15

    It is shown that, in a simple coupler where one of the waveguides is subject to controlled losses of the electric field, it is possible to observe an optical analog of the linear and nonlinear quantum Zeno effects. The phenomenon consists in a counterintuitive enhancement of transparency of the coupler with an increase of the dissipation and represents an optical analog of the quantum Zeno effect. Experimental realization of the phenomenon based on the use of chalcogenide glasses is proposed. The system allows for observation of the crossover between the linear and nonlinear Zeno effects, as well as the effective manipulation of light transmission through the coupler.

  10. Inductive coupler for downhole components and method for making same

    DOEpatents

    Hall, David R.; Hall, Jr., H. Tracy; Pixton, David S.; Dahlgren, Scott; Sneddon, Cameron; Fox, Joe; Briscoe, Michael A.

    2006-10-03

    An inductive coupler for downhole components. The inductive coupler includes an annular housing having a recess defined by a bottom portion and two opposing side wall portions. At least one side wall portion includes a lip extending toward but not reaching the other side wall portion. A plurality of generally U-shaped MCEI segments, preferably comprised of ferrite, are disposed in the recess and aligned so as to form a circular trough. The coupler further includes a conductor disposed within the circular trough and a polymer filling spaces between the segments, the annular housing and the conductor.

  11. High performance storable propellant resistojet

    NASA Technical Reports Server (NTRS)

    Vaughan, C. E.

    1992-01-01

    From 1965 until 1985 resistojets were used for a limited number of space missions. Capability increased in stages from an initial application using a 90 W gN2 thruster operating at 123 sec specific impulse (Isp) to a 830 W N2H4 thruster operating at 305 sec Isp. Prior to 1985 fewer than 100 resistojets were known to have been deployed on spacecraft. Building on this base NASA embarked upon the High Performance Storable Propellant Resistojet (HPSPR) program to significantly advance the resistojet state-of-the-art. Higher performance thrusters promised to increase the market demand for resistojets and enable space missions requiring higher performance. During the program three resistojets were fabricated and tested. High temperature wire and coupon materials tests were completed. A life test was conducted on an advanced gas generator.

  12. High performance magnetically controllable microturbines.

    PubMed

    Tian, Ye; Zhang, Yong-Lai; Ku, Jin-Feng; He, Yan; Xu, Bin-Bin; Chen, Qi-Dai; Xia, Hong; Sun, Hong-Bo

    2010-11-01

    Reported in this paper is two-photon photopolymerization (TPP) fabrication of magnetic microturbines with high surface smoothness towards microfluids mixing. As the key component of the magnetic photoresist, Fe(3)O(4) nanoparticles were carefully screened for homogeneous doping. In this work, oleic acid stabilized Fe(3)O(4) nanoparticles synthesized via high-temperature induced organic phase decomposition of an iron precursor show evident advantages in particle morphology. After modification with propoxylated trimethylolpropane triacrylate (PO(3)-TMPTA, a kind of cross-linker), the magnetic nanoparticles were homogeneously doped in acrylate-based photoresist for TPP fabrication of microstructures. Finally, a magnetic microturbine was successfully fabricated as an active mixing device for remote control of microfluids blending. The development of high quality magnetic photoresists would lead to high performance magnetically controllable microdevices for lab-on-a-chip (LOC) applications. PMID:20721411

  13. FPGA Based High Performance Computing

    SciTech Connect

    Bennett, Dave; Mason, Jeff; Sundararajan, Prasanna; Dellinger, Erik; Putnam, Andrew; Storaasli, Olaf O

    2008-01-01

    Current high performance computing (HPC) applications are found in many consumer, industrial and research fields. From web searches to auto crash simulations to weather predictions, these applications require large amounts of power by the compute farms and supercomputers required to run them. The demand for more and faster computation continues to increase along with an even sharper increase in the cost of the power required to operate and cool these installations. The ability of standard processor based systems to address these needs has declined in both speed of computation and in power consumption over the past few years. This paper presents a new method of computation based upon programmable logic as represented by Field Programmable Gate Arrays (FPGAs) that addresses these needs in a manner requiring only minimal changes to the current software design environment.

  14. High-performance conformal sensors employing single-crystal silicon nanomembranes

    NASA Astrophysics Data System (ADS)

    Xu, Xiaochuan; Subbaraman, Harish; Chakravarty, Swapnajit; Chen, Ray T.

    2014-03-01

    We demonstrate light-weight, conformal, and high-performance flexible sensors fabricated on a large area (>2 cm × 2 cm) silicon nanomembrane transferred onto a flexible substrate. Linear L13 photonic crystal microcavities are designed to provide high quality factors on the flexible platform. Subwavelength grating (SWG) couplers are employed in order to enable efficient light coupling to the device using a single mode fiber. Photonic crystal tapers are implemented at the strip-photonic crystal waveguide interfaces to minimize loss. Preliminary chemical sensing data suggests a sensitivity of 75nm/RIU. Bending tests are further performed in order to demonstrate sensitivityindependent operation.

  15. Multipacting Simulations of TTF-III Coupler Components

    SciTech Connect

    Ge, L.; Adolphsen, Chris E.; Ko, L.K.; Li, Z.; Ng, C.; Schussman, G.; Wang, F.; Rusnak, B.; /LLNL, Livermore

    2007-09-10

    The TTF-III power coupler adopted for the ILC baseline cavity design has shown a tendency to have long initial high power processing time. A possible cause for the long processing time is believed to be multipacting in various regions of the coupler. To understand performance limitations during high power processing, SLAC has built a flexible high-power coupler test stand. The plan is to test individual sections of the coupler, which includes the cold and warm coaxes, the cold and warm bellows, and the cold window, using the test stand to identify problematic regions. To provide insights for the high power test, detailed numerical simulations of multipacting for these sections will be performed using the 3D multipacting code Track3P.

  16. 49 CFR 179.14 - Coupler vertical restraint system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... tank car shall be equipped with couplers capable of sustaining, without disengagement or material... successful when a vertical disengagement or material failure does not occur during the application of any...

  17. 49 CFR 179.14 - Coupler vertical restraint system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... tank car shall be equipped with couplers capable of sustaining, without disengagement or material... successful when a vertical disengagement or material failure does not occur during the application of any...

  18. 49 CFR 179.14 - Coupler vertical restraint system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... tank car shall be equipped with couplers capable of sustaining, without disengagement or material... successful when a vertical disengagement or material failure does not occur during the application of any...

  19. 49 CFR 179.14 - Coupler vertical restraint system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... tank car shall be equipped with couplers capable of sustaining, without disengagement or material... successful when a vertical disengagement or material failure does not occur during the application of any...

  20. Accurate theoretical and experimental characterization of optical grating coupler.

    PubMed

    Fesharaki, Faezeh; Hossain, Nadir; Vigne, Sebastien; Chaker, Mohamed; Wu, Ke

    2016-09-01

    Periodic structures, acting as reflectors, filters, and couplers, are a fundamental building block section in many optical devices. In this paper, a three-dimensional simulation of a grating coupler, a well-known periodic structure, is conducted. Guided waves and leakage characteristics of an out-of-plane grating coupler are studied in detail, and its coupling efficiency is examined. Furthermore, a numerical calibration analysis is applied through a commercial software package on the basis of a full-wave finite-element method to calculate the complex propagation constant of the structure and to evaluate the radiation pattern. For experimental evaluation, an optimized grating coupler is fabricated using electron-beam lithography technique and plasma etching. An excellent agreement between simulations and measurements is observed, thereby validating the demonstrated method. PMID:27607706

  1. IET. Coupling station. Man holds flexible couplers to reactor Dolly ...

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

    IET. Coupling station. Man holds flexible couplers to reactor Dolly and HTRE rig. Date: April 22, 1955. INEEL negative no. 55-1010 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

  2. PREFACE: High Performance Computing Symposium 2011

    NASA Astrophysics Data System (ADS)

    Talon, Suzanne; Mousseau, Normand; Peslherbe, Gilles; Bertrand, François; Gauthier, Pierre; Kadem, Lyes; Moitessier, Nicolas; Rouleau, Guy; Wittig, Rod

    2012-02-01

    HPCS (High Performance Computing Symposium) is a multidisciplinary conference that focuses on research involving High Performance Computing and its application. Attended by Canadian and international experts and renowned researchers in the sciences, all areas of engineering, the applied sciences, medicine and life sciences, mathematics, the humanities and social sciences, it is Canada's pre-eminent forum for HPC. The 25th edition was held in Montréal, at the Université du Québec à Montréal, from 15-17 June and focused on HPC in Medical Science. The conference was preceded by tutorials held at Concordia University, where 56 participants learned about HPC best practices, GPU computing, parallel computing, debugging and a number of high-level languages. 274 participants from six countries attended the main conference, which involved 11 invited and 37 contributed oral presentations, 33 posters, and an exhibit hall with 16 booths from our sponsors. The work that follows is a collection of papers presented at the conference covering HPC topics ranging from computer science to bioinformatics. They are divided here into four sections: HPC in Engineering, Physics and Materials Science, HPC in Medical Science, HPC Enabling to Explore our World and New Algorithms for HPC. We would once more like to thank the participants and invited speakers, the members of the Scientific Committee, the referees who spent time reviewing the papers and our invaluable sponsors. To hear the invited talks and learn about 25 years of HPC development in Canada visit the Symposium website: http://2011.hpcs.ca/lang/en/conference/keynote-speakers/ Enjoy the excellent papers that follow, and we look forward to seeing you in Vancouver for HPCS 2012! Gilles Peslherbe Chair of the Scientific Committee Normand Mousseau Co-Chair of HPCS 2011 Suzanne Talon Chair of the Organizing Committee UQAM Sponsors The PDF also contains photographs from the conference banquet.

  3. High performance Cu adhesion coating

    SciTech Connect

    Lee, K.W.; Viehbeck, A.; Chen, W.R.; Ree, M.

    1996-12-31

    Poly(arylene ether benzimidazole) (PAEBI) is a high performance thermoplastic polymer with imidazole functional groups forming the polymer backbone structure. It is proposed that upon coating PAEBI onto a copper surface the imidazole groups of PAEBI form a bond with or chelate to the copper surface resulting in strong adhesion between the copper and polymer. Adhesion of PAEBI to other polymers such as poly(biphenyl dianhydride-p-phenylene diamine) (BPDA-PDA) polyimide is also quite good and stable. The resulting locus of failure as studied by XPS and IR indicates that PAEBI gives strong cohesive adhesion to copper. Due to its good adhesion and mechanical properties, PAEBI can be used in fabricating thin film semiconductor packages such as multichip module dielectric (MCM-D) structures. In these applications, a thin PAEBI coating is applied directly to a wiring layer for enhancing adhesion to both the copper wiring and the polymer dielectric surface. In addition, a thin layer of PAEBI can also function as a protection layer for the copper wiring, eliminating the need for Cr or Ni barrier metallurgies and thus significantly reducing the number of process steps.

  4. ALMA high performance nutating subreflector

    NASA Astrophysics Data System (ADS)

    Gasho, Victor L.; Radford, Simon J. E.; Kingsley, Jeffrey S.

    2003-02-01

    For the international ALMA project"s prototype antennas, we have developed a high performance, reactionless nutating subreflector (chopping secondary mirror). This single axis mechanism can switch the antenna"s optical axis by +/-1.5" within 10 ms or +/-5" within 20 ms and maintains pointing stability within the antenna"s 0.6" error budget. The light weight 75 cm diameter subreflector is made of carbon fiber composite to achieve a low moment of inertia, <0.25 kg m2. Its reflecting surface was formed in a compression mold. Carbon fiber is also used together with Invar in the supporting structure for thermal stability. Both the subreflector and the moving coil motors are mounted on flex pivots and the motor magnets counter rotate to absorb the nutation reaction force. Auxiliary motors provide active damping of external disturbances, such as wind gusts. Non contacting optical sensors measure the positions of the subreflector and the motor rocker. The principle mechanical resonance around 20 Hz is compensated with a digital PID servo loop that provides a closed loop bandwidth near 100 Hz. Shaped transitions are used to avoid overstressing mechanical links.

  5. High performance aerated lagoon systems

    SciTech Connect

    Rich, L.

    1999-08-01

    At a time when less money is available for wastewater treatment facilities and there is increased competition for the local tax dollar, regulatory agencies are enforcing stricter effluent limits on treatment discharges. A solution for both municipalities and industry is to use aerated lagoon systems designed to meet these limits. This monograph, prepared by a recognized expert in the field, provides methods for the rational design of a wide variety of high-performance aerated lagoon systems. Such systems range from those that can be depended upon to meet secondary treatment standards alone to those that, with the inclusion of intermittent sand filters or elements of sequenced biological reactor (SBR) technology, can also provide for nitrification and nutrient removal. Considerable emphasis is placed on the use of appropriate performance parameters, and an entire chapter is devoted to diagnosing performance failures. Contents include: principles of microbiological processes, control of algae, benthal stabilization, design for CBOD removal, design for nitrification and denitrification in suspended-growth systems, design for nitrification in attached-growth systems, phosphorus removal, diagnosing performance.

  6. The aging process of optical couplers by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Bednarek, Lukas; Marcinka, Ondrej; Perecar, Frantisek; Papes, Martin; Hajek, Lukas; Nedoma, Jan; Vasinek, Vladimir

    2015-08-01

    Scientists have recently discovered that the ageing process of optical elements is faster than it was originally anticipated. It is mostly due to the multiple increases of the optical power in optical components, the introduction of wavelength division multiplexers and, overall, the increased flow of traffic in optical communications. This article examines the ageing process of optical couplers and it focuses on their performance parameters. It describes the measurement procedure followed by the evaluation of the measurement results. To accelerate the ageing process, gamma irradiation from 60Co was used. The results of the measurements of the optical coupler with one input and eight outputs (1:8) were summarized. The results gained by measuring of the optical coupler with one input and four outputs (1:4) as well as of the optical couplers with one input and two outputs (1:2) with different split ratios were also processed. The optical powers were measured on the input and the outputs of each branch of each optical coupler at the wavelengths of 1310 nm and 1550 nm. The parameters of the optical couplers were subsequently calculated according to the appropriate formulas. These parameters were the insertion loss of the individual branches, split ratio, total losses, homogeneity of the losses and directionalities alias cross-talk between the individual output branches. The gathered data were summarized before and after the first irradiation when the configuration of the couplers was 1:8 and 1:4. The data were summarized after the third irradiation when the configuration of the couplers was 1:2.

  7. Low-Field Accelerator Structure Couplers and Design Techniques

    SciTech Connect

    Nantista, C

    2004-07-29

    Recent experience with X-band accelerator structure development has shown the rf input coupler to be the region most prone to rf breakdown and degradation, effectively limiting the operating gradient. A major factor in this appears to be high magnetic fields at the sharp edges of the coupling irises. As a first response to this problem, couplers with rounded and thickened iris horns have been employed and successfully tested at high power. To further reduce fields for higher power flow, conceptually new coupler designs have been developed, in which power is coupled through the broadwall of the feed waveguide, rather than through terminating irises. A 'mode launcher' coupler, which launches the TM{sub 01} mode in circular waveguide before coupling through a matching cell into the main structure, has been tested with great success. With peak surface fields below those in the body of the structure, this coupler represented a break-through in the NLC structure program. The design of this coupler and of variations which use beamline space more efficiently are described here. The latter include a coupler in which power passes directly through an iris in the broad wall of the rectangular waveguide into a matching cell, also successfully implemented, and a variation which makes the waveguide itself an accelerating cell. The authors also discuss in some detail a couple of techniques for matching such couplers to travelling-wave structures using a field solver. The first exploits the cell number independence of a travelling-wave match, and the second optimizes using the fields of an internally driven structure.

  8. Power coupler kick of the TRIUMF ICM capture cavities

    NASA Astrophysics Data System (ADS)

    Yan, Fang; E. Laxdal, R.; Zvyagintsev, V.; Yu., Chao; C., Gong; Koscielniak, S.

    2011-06-01

    The TRIUMF Injector CryoModule (ICM) adapted two superconducting single cavities as the capture section for the low injecting energy of 100 keV electrons. Coupler kick induced beam deflection and projected emittance growth are one of the prime concerns of the beam stability, especially at low energies. In low energy applications, the electron velocity changes rapidly inside the cavity, which makes the numerical analysis much more complicated. The commonly used theoretical formulas of the direct integral or the Panofsky-Wenzel theorem is not suitable for the kick calculation of β < 1 electrons. Despite that, the above mentioned kick calculation method doesn't consider injecting electron energy, the beam offset due to the coupler kick may not be negligible because of the low injection energy even if the kick is optimized. Thus the beam dynamics code TRACK is used here for the simulation of the power coupler kick perturbation. The coupler kick can be compensated for by a judicious choice of the coupler position in successive cavities from upstream to downstream. The simulation shows that because of the adiabatic damping by the following superconducting 9-cell cavity, even for the worst orbit distortion case after two capture cavities, the kick is still acceptable at the exit of the ICM after reaching 10 MeV. This paper presents the analysis of the transverse kick and the projected emittance growth induced by the coupler for β < 1 electrons. The simulated results of the TRIUMF ICM capture cavities are described and presented.

  9. High Performance Solution Processable TFTs

    NASA Astrophysics Data System (ADS)

    Gundlach, David

    2008-03-01

    Organic-based electronic devices offer the potential to significantly impact the functionality and pervasiveness of large-area electronics. We report on soluble acene-based organic thin film transistors (OTFTs) where the microstructure of as-cast films can be precisely controlled via interfacial chemistry. Chemically tailoring the source/drain contact interface is a novel route to self-patterning of soluble small molecule organic semiconductors and enables the growth of highly ordered regions along opposing contact edges which extend into the transistor channel. The unique film forming properties of soluble fluorinated anthradithiophenes allows us to fabricate high performance OTFTs, OTFT circuits, and to deterministically study the influence of the film microstructure on the electrical characteristics of devices. Most recently we have grown single crystals of soluble fluorinated anthradithiophenes by vapor transport method allowing us to probe deeper into their intrinsic properties and determine the potential and limitations of this promising family of oligomers for use in organic-based electronic devices. Co-Authors: O. D. Jurchescu^1,4, B. H. Hamadani^1, S. K. Park^4, D. A. Mourey^4, S. Subramanian^5, A. J. Moad^2, R. J. Kline^3, L. C. Teague^2, J. G. Kushmerick^2, L. J. Richter^2, T. N. Jackson^4, and J. E. Anthony^5 ^1Semiconductor Electronics Division, ^2Surface and Microanalysis Science Division, ^3Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 ^4Department of Electrical Engineering, The Pennsylvania State University, University Park, PA 16802 ^5Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055

  10. High-Performance Bipropellant Engine

    NASA Technical Reports Server (NTRS)

    Biaglow, James A.; Schneider, Steven J.

    1999-01-01

    TRW, under contract to the NASA Lewis Research Center, has successfully completed over 10 000 sec of testing of a rhenium thrust chamber manufactured via a new-generation powder metallurgy. High performance was achieved for two different propellants, N2O4- N2H4 and N2O4 -MMH. TRW conducted 44 tests with N2O4-N2H4, accumulating 5230 sec of operating time with maximum burn times of 600 sec and a specific impulse Isp of 333 sec. Seventeen tests were conducted with N2O4-MMH for an additional 4789 sec and a maximum Isp of 324 sec, with a maximum firing duration of 700 sec. Together, the 61 tests totalled 10 019 sec of operating time, with the chamber remaining in excellent condition. Of these tests, 11 lasted 600 to 700 sec. The performance of radiation-cooled rocket engines is limited by their operating temperature. For the past two to three decades, the majority of radiation-cooled rockets were composed of a high-temperature niobium alloy (C103) with a disilicide oxide coating (R512) for oxidation resistance. The R512 coating practically limits the operating temperature to 1370 C. For the Earth-storable bipropellants commonly used in satellite and spacecraft propulsion systems, a significant amount of fuel film cooling is needed. The large film-cooling requirement extracts a large penalty in performance from incomplete mixing and combustion. A material system with a higher temperature capability has been matured to the point where engines are being readied for flight, particularly the 100-lb-thrust class engine. This system has powder rhenium (Re) as a substrate material with an iridium (Ir) oxidation-resistant coating. Again, the operating temperature is limited by the coating; however, Ir is capable of long-life operation at 2200 C. For Earth-storable bipropellants, this allows for the virtual elimination of fuel film cooling (some film cooling is used for thermal control of the head end). This has resulted in significant increases in specific impulse performance

  11. A Component Architecture for High-Performance Computing

    SciTech Connect

    Bernholdt, D E; Elwasif, W R; Kohl, J A; Epperly, T G W

    2003-01-21

    The Common Component Architecture (CCA) provides a means for developers to manage the complexity of large-scale scientific software systems and to move toward a ''plug and play'' environment for high-performance computing. The CCA model allows for a direct connection between components within the same process to maintain performance on inter-component calls. It is neutral with respect to parallelism, allowing components to use whatever means they desire to communicate within their parallel ''cohort.'' We will discuss in detail the importance of performance in the design of the CCA and will analyze the performance costs associated with features of the CCA.

  12. A Component Architecture for High-Performance Scientific Computing

    SciTech Connect

    Bernholdt, D E; Allan, B A; Armstrong, R; Bertrand, F; Chiu, K; Dahlgren, T L; Damevski, K; Elwasif, W R; Epperly, T W; Govindaraju, M; Katz, D S; Kohl, J A; Krishnan, M; Kumfert, G; Larson, J W; Lefantzi, S; Lewis, M J; Malony, A D; McInnes, L C; Nieplocha, J; Norris, B; Parker, S G; Ray, J; Shende, S; Windus, T L; Zhou, S

    2004-12-14

    The Common Component Architecture (CCA) provides a means for software developers to manage the complexity of large-scale scientific simulations and to move toward a plug-and-play environment for high-performance computing. In the scientific computing context, component models also promote collaboration using independently developed software, thereby allowing particular individuals or groups to focus on the aspects of greatest interest to them. The CCA supports parallel and distributed computing as well as local high-performance connections between components in a language-independent manner. The design places minimal requirements on components and thus facilitates the integration of existing code into the CCA environment. The CCA model imposes minimal overhead to minimize the impact on application performance. The focus on high performance distinguishes the CCA from most other component models. The CCA is being applied within an increasing range of disciplines, including combustion research, global climate simulation, and computational chemistry.

  13. A Component Architecture for High-Performance Scientific Computing

    SciTech Connect

    Bernholdt, David E; Allan, Benjamin A; Armstrong, Robert C; Bertrand, Felipe; Chiu, Kenneth; Dahlgren, Tamara L; Damevski, Kostadin; Elwasif, Wael R; Epperly, Thomas G; Govindaraju, Madhusudhan; Katz, Daniel S; Kohl, James A; Krishnan, Manoj Kumar; Kumfert, Gary K; Larson, J Walter; Lefantzi, Sophia; Lewis, Michael J; Malony, Allen D; McInnes, Lois C; Nieplocha, Jarek; Norris, Boyana; Parker, Steven G; Ray, Jaideep; Shende, Sameer; Windus, Theresa L; Zhou, Shujia

    2006-07-03

    The Common Component Architecture (CCA) provides a means for software developers to manage the complexity of large-scale scientific simulations and to move toward a plug-and-play environment for high-performance computing. In the scientific computing context, component models also promote collaboration using independently developed software, thereby allowing particular individuals or groups to focus on the aspects of greatest interest to them. The CCA supports parallel and distributed computing as well as local high-performance connections between components in a language-independent manner. The design places minimal requirements on components and thus facilitates the integration of existing code into the CCA environment. The CCA model imposes minimal overhead to minimize the impact on application performance. The focus on high performance distinguishes the CCA from most other component models. The CCA is being applied within an increasing range of disciplines, including combustion research, global climate simulation, and computational chemistry.

  14. Carpet Aids Learning in High Performance Schools

    ERIC Educational Resources Information Center

    Hurd, Frank

    2009-01-01

    The Healthy and High Performance Schools Act of 2002 has set specific federal guidelines for school design, and developed a federal/state partnership program to assist local districts in their school planning. According to the Collaborative for High Performance Schools (CHPS), high-performance schools are, among other things, healthy, comfortable,…

  15. High-Performance Schools Make Cents.

    ERIC Educational Resources Information Center

    Nielsen-Palacios, Christian

    2003-01-01

    Describes the educational benefits of high-performance schools, buildings that are efficient, healthy, safe, and easy to operate and maintain. Also briefly describes how to create a high-performance school drawn from volume I (Planning) of the three-volume Collaborative for High Performance Schools (CHPS) "Best Practices Manual." (For more…

  16. High-performance automatic image registration for remote sensing

    NASA Astrophysics Data System (ADS)

    Chalermwat, Prachya

    Image registration is one of the crucial steps in the analysis of remotely sensed data. A new acquired image must be transformed, using image registration techniques, to match the orientation and scale of previous related images. Image registration requires intensive computational effort not only because of its computational complexity, but also due to the continuous increase in image resolution and spectral bands. Thus, high-performance computing techniques for image registration are critically needed. Very few works have addressed image registration on contemporary high-performance computing systems. Furthermore, issues of load balancing, scalability, and formal analysis of algorithmic efficiency were seldom considered. This dissertation introduces high-performance automatic image registration (HAIR) algorithms. High performance is achieved by: (1) reduction in search data, (2) reduction in search space, and (3) parallel processing. Reduction in search data is achieved by performing registration using only subimages. A new metric called registrability is used to select those subimages such that accuracy is maintained. In addition, a histogram comparison is used to discard anomalous subimages, such as those with clouds. Further data reduction is obtained using an iterative refinement search (IRA), which exploits the wavelet multi-resolution representation. This technique starts searching images with lower resolution first, then refining the results using higher resolution images to use the least possible data points in the overall registration task. Reduction of search space is achieved through two methods. First, iterative refinement reduces dramatically the number of solutions examined. In addition, genetic algorithms were also used to further expedite the search. Parallel processing techniques have been utilized to provide coarse-grain load-balanced parallel algorithms based on iterative refinement as well as genetic algorithms. Two hybrid algorithms have been

  17. Understanding and Improving High-Performance I/O Subsystems

    NASA Technical Reports Server (NTRS)

    El-Ghazawi, Tarek A.; Frieder, Gideon; Clark, A. James

    1996-01-01

    This research program has been conducted in the framework of the NASA Earth and Space Science (ESS) evaluations led by Dr. Thomas Sterling. In addition to the many important research findings for NASA and the prestigious publications, the program has helped orienting the doctoral research program of two students towards parallel input/output in high-performance computing. Further, the experimental results in the case of the MasPar were very useful and helpful to MasPar with which the P.I. has had many interactions with the technical management. The contributions of this program are drawn from three experimental studies conducted on different high-performance computing testbeds/platforms, and therefore presented in 3 different segments as follows: 1. Evaluating the parallel input/output subsystem of a NASA high-performance computing testbeds, namely the MasPar MP- 1 and MP-2; 2. Characterizing the physical input/output request patterns for NASA ESS applications, which used the Beowulf platform; and 3. Dynamic scheduling techniques for hiding I/O latency in parallel applications such as sparse matrix computations. This study also has been conducted on the Intel Paragon and has also provided an experimental evaluation for the Parallel File System (PFS) and parallel input/output on the Paragon. This report is organized as follows. The summary of findings discusses the results of each of the aforementioned 3 studies. Three appendices, each containing a key scholarly research paper that details the work in one of the studies are included.

  18. All-optical logic devices with cascaded nonlinear couplers.

    PubMed

    Wang, Y; Wang, Z H; Bialkowski, M E

    2000-08-10

    The switching behaviors of cascaded nonlinear couplers were investigated. They have nearly ideal digital-switching characteristics, and their output power levels can be adjusted by means of varying the nonlinear coupling coefficient of the final coupler. The two-input excitation nonlinear cascaded couplers can perform not only switching operations but also a series of logic operations. The logic operations depend mainly on the coupling length of the two-input coupler and its initial inputs. The power corresponding to the rising and falling ridge of the logic operating waveforms can be shifted effectively by means of varying the switching power of the reshaper. Allowable ranges of three important parameters--coupling length of the two-input coupler L(1), bias optical power P(bia), and phase difference psi between the signal and bias beams for six fundamental logic operations--were calculated. Curves for design considerations and suggestions for the best choice of parameters for stable and reliable logic operations and, or, xor, nand, nor, and nxor are also presented individually. PMID:18349996

  19. Apodized grating coupler using fully-etched nanostructures

    NASA Astrophysics Data System (ADS)

    Wu, Hua; Li, Chong; Li, Zhi-Yong; Guo, Xia

    2016-08-01

    A two-dimensional apodized grating coupler for interfacing between single-mode fiber and photonic circuit is demonstrated in order to bridge the mode gap between the grating coupler and optical fiber. The grating grooves of the grating couplers are realized by columns of fully etched nanostructures, which are utilized to digitally tailor the effective refractive index of each groove in order to obtain the Gaussian-like output diffractive mode and then enhance the coupling efficiency. Compared with that of the uniform grating coupler, the coupling efficiency of the apodized grating coupler is increased by 4.3% and 5.7%, respectively, for the nanoholes and nanorectangles as refractive index tunes layer. Project supported by the National Natural Science Foundation of China (Grant Nos. 61222501, 61335004, and 61505003), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20111103110019), the Postdoctoral Science Foundation of Beijing Funded Project, China (Grant No. Q6002012201502), and the Science and Technology Research Project of Jiangxi Provincial Education Department, China (Grant No. GJJ150998).

  20. Magnetically controllable wavelength-division-multiplexing fiber coupler.

    PubMed

    Lin, Wei; Zhang, Hao; Song, Binbin; Miao, Yinping; Liu, Bo; Yan, Donglin; Liu, Yange

    2015-05-01

    In this paper, a magnetically controllable wavelength-division-multiplexing (WDM) fiber coupler has been proposed and experimentally demonstrated. A theoretical model has been established to analyze the influences of the weak as well as strong couplings to the wavelength tunability of this coupler. Experimental results show that the operation wavelength tunability of the proposed WDM coupler could be fulfilled for an applied magnetic field intensity range of 0 Oe to 500 Oe, and particularly it possesses high operation performances within the magnetic field intensity ranging from 25 Oe to 125 Oe when additional transmission loss and isolation are both considered. Within this range, the two selected channels show the wavelength tunability of 0.05 nm/Oe and 0.0744 nm/Oe, respectively, and the isolation between the two branches is higher than 24.089 dB. Owing to its high isolation, good splitting ratio stability, and high wavelength tunability, the proposed controllable WDM coupler is anticipated to find potential applications in such fields as fiber laser, fiber sensing and fiber-optic communications. Moreover, the fiber coupler integrated with the magnetic fluid would be valuable for the design of magnetically controllable mode-division-multiplexing devices. PMID:25969208

  1. High Performance Computing in Solid Earth Sciences

    NASA Astrophysics Data System (ADS)

    Manea, V. C.; Manea, M.; Pomeran, M.; Besutiu, L.; Zlagnean, L.

    2012-04-01

    Presently, the solid earth sciences started to move towards implementing high performance computational (HPC) research facilities. One of the key tenants of HPC is performance, and designing a HPC solution tailored to a specific research field as solid earth that represents an optimum price/performance ratio is often a challenge. The HPC system performance strongly depends on the software-hardware interaction, and therefore prior knowledge on how well specific parallelized software performs on different HPC architectures can weight significantly on choosing the final configuration. In this paper we present benchmark results from two different HPC systems: one low-end HPCC (Horus) with 300 cores and 1.6 TFlops theoretical peak performance, and one high-end HPCC (CyberDyn) with 1344 cores and 11.2 TFlops theoretical peak performance. The software benchmark used in this paper is the open source package CitcomS, which is widely used in the solid earth community (www.geodynamics.org). Testing a CFD code specific for earth sciences, the HPC system Horus based on Gigabit Ethernet performed remarkably well compared with its counterpart Cyeberdyn which is based on Infiniband QDR fabric, but only for a relatively small number of computing cores (96). However, increasing the mesh size and the number of computing cores the HPCC CyberDyn starts outperforming the HPCC Horus because of the low-latency high-speed QDR network dedicated to MPI traffic. Since presently we are moving towards high-resolution simulations for geodynamic predictions that require the same scale as observations, HPC facilities used in earth sciences should benefit from larger up-front investment in future systems that are based on high-speed interconnects.

  2. Scalable resource management in high performance computers.

    SciTech Connect

    Frachtenberg, E.; Petrini, F.; Fernandez Peinador, J.; Coll, S.

    2002-01-01

    Clusters of workstations have emerged as an important platform for building cost-effective, scalable and highly-available computers. Although many hardware solutions are available today, the largest challenge in making large-scale clusters usable lies in the system software. In this paper we present STORM, a resource management tool designed to provide scalability, low overhead and the flexibility necessary to efficiently support and analyze a wide range of job scheduling algorithms. STORM achieves these feats by closely integrating the management daemons with the low-level features that are common in state-of-the-art high-performance system area networks. The architecture of STORM is based on three main technical innovations. First, a sizable part of the scheduler runs in the thread processor located on the network interface. Second, we use hardware collectives that are highly scalable both for implementing control heartbeats and to distribute the binary of a parallel job in near-constant time, irrespective of job and machine sizes. Third, we use an I/O bypass protocol that allows fast data movements from the file system to the communication buffers in the network interface and vice versa. The experimental results show that STORM can launch a job with a binary of 12MB on a 64 processor/32 node cluster in less than 0.25 sec on an empty network, in less than 0.45 sec when all the processors are busy computing other jobs, and in less than 0.65 sec when the network is flooded with a background traffic. This paper provides experimental and analytical evidence that these results scale to a much larger number of nodes. To the best of our knowledge, STORM is at least two orders of magnitude faster than existing production schedulers in launching jobs, performing resource management tasks and gang scheduling.

  3. Simulations of optical sensors fabricated from metallic rods couplers

    SciTech Connect

    Singh, M. R.; Balakrishanan, Shankar

    2014-03-31

    We have developed the optical sensing mechanism of photonic couplers fabricated from the periodically arranged metallic rods. The metallic rod lattice is embedded between two dielectric material waveguides. This structure is called metallic coupler. Using the transfer matrix method, expressions for the reflection and transmission coefficients of electromagnetic wave propagating in waveguides have been obtained. We found that for certain energies, the electromagnetic wave is totally reflected from the coupler. Similarly, for a certain energy range the light is totally transmitted. It has also been found that by changing the periodicity of the metallic rods, the transmitted energy can be reflected. The periodicity of the metallic lattice can be modified by applying an external stress or pressure. In other words, the system can be used as stress and pressure sensors. The present findings can be used to make new types photonic sensors.

  4. Thin-ribbon tapered coupler for dielectric waveguides

    NASA Technical Reports Server (NTRS)

    Yeh, C.; Otoshi, T. Y.; Shimabukuro, F. I.

    1994-01-01

    A recent discovery shows that a high-dielectric constant, low-loss, solid material can be made into a ribbon-like waveguide structure to yield an attenuation constant of less than 0.02 dB/m for single-mode guidance of millimeter/submillimeter waves. One of the crucial components that must be invented in order to guarantee the low-loss utilization of this dielectric-waveguide guiding system is the excitation coupler. The traditional tapered-to-a-point coupler for a dielectric rod waveguide fails when the dielectric constant of the dielectric waveguide is large. This article presents a new way to design a low-loss coupler for a high- or low-dielectric constant dielectric waveguide for millimeter or submillimeter waves.

  5. Codesign and high-performance computing: scenes and crisis

    NASA Astrophysics Data System (ADS)

    Hartenstein, Reiner W.; Becker, Juergen; Herz, Michael; Nageldinger, Ulrich

    1996-10-01

    During the development of scientific disciplines, mainstream periods alternate with revolution periods, where 'out of the way disciplines' can become a mainstream. Just in the moment increasing turbulences announce a new revolution. The variety of 'high performance computing' scenes will be mixed up. Can an increasing application of structurally programmable hardware platforms (computing by the yard) break the monopoly of the von Neumann mainstream paradigm (computing in time) also in multipurpose hardware? From a co-design point of view, the paper tries to provide an overview through the turbulences and tendencies, and introduces a fundamentally new machine paradigm, which uses a field-programmable data path array (FPDPA) providing instruction level parallelism. The paper drafts a structured design space for all kinds of parallel algorithm implementations and platforms: procedural programming versus structural programing, concurrent versus parallel, hardwired versus reconfigurable. A structured view by rearranging the variety of computing science scenes seems to be feasible.

  6. Presentation of floating mass transducer and Vibroplasty couplers on CT and cone beam CT.

    PubMed

    Mlynski, Robert; Nguyen, Thi Dao; Plontke, Stefan K; Kösling, Sabrina

    2014-04-01

    Various titanium coupling elements, Vibroplasty Couplers, maintaining the attachment of the Floating Mass Transducer (FMT) of the active middle ear implant Vibrant Soundbridge (VSB) to the round window, the stapes suprastructure or the stapes footplate are in use to optimally transfer energy from the FMT to the inner ear fluids. In certain cases it is of interest to radiologically verify the correct position of the FMT coupler assembly. The imaging appearance of FMT connected to these couplers, however, is not well known. The aim of this study was to present the radiological appearance of correctly positioned Vibroplasty Couplers together with the FMT using two different imaging techniques. Vibroplasty Couplers were attached to the FMT of a Vibrant Soundbridge and implanted in formalin fixed human temporal bones. Five FMT coupler assemblies were implanted in different positions: conventionally to the incus, a Bell-Coupler, a CliP-Coupler, a Round Window-Coupler and an Oval Window-Coupler. High spatial resolution imaging with Multi-Detector CT (MDCT) and Cone Beam CT (CBCT) was performed in each specimen. Images were blind evaluated by two radiologists on a visual basis. Middle ear details, identification of FMT and coupler, position of FMT coupler assembly and artefacts were assessed. CBCT showed a better spatial resolution and a higher visual image quality than MDCT, but there was no significant advantage over MDCT in delineating the structures or the temporal bone of the FMT Coupler assemblies. The FMT with its coupler element could be clearly identified in the two imaging techniques. The correct positioning of the FMT and all types of couplers could be demonstrated. Both methods, MDCT and CBCT, are appropriate methods for postoperative localization of FMT in combination with Vibroplasty Couplers and for verifying their correct position. If CBCT is available, this method is recommended due to the better spatial resolution and less metal artifacts. PMID:23529745

  7. Passive PT -symmetric couplers without complex optical potentials

    NASA Astrophysics Data System (ADS)

    Lee, Yi-Chan; Liu, Jibing; Chuang, You-Lin; Hsieh, Min-Hsiu; Lee, Ray-Kuang

    2015-11-01

    In addition to the implementation of parity-time-(PT -) symmetric optical systems by carefully and actively controlling the gain and loss, we show that a 2 ×2 PT -symmetric Hamiltonian has a unitarily equivalent representation without complex optical potentials in the resulting optical coupler. Through the Naimark dilation in operator algebra, passive PT -symmetric couplers can thus be implemented with a refractive index of real values and asymmetric coupling coefficients. This opens up the possibility to implement general PT -symmetric systems with state-of-the-art asymmetric slab waveguides, dissimilar optical fibers, or cavities with chiral mirrors.

  8. Flexible polymeric rib waveguide with self-align couplers system.

    PubMed

    Huang, Cheng-Sheng; Wang, Wei-Chih

    2008-01-01

    The authors report a polymeric based rib waveguide with U shape self-align fiber couplers system using a simple micromolding process with SU8 as a molding material and polydimethysiloxane as a waveguide material. The material is used for its good optical transparency, low surface tension, biocompatibility, and durability. Furthermore, the material is highly formable. This unique fabrication molding technique provides a means of keeping the material and manufacturing costs to a minimum. The self-align fiber couplers system also proves a fast and simple means of light coupling. The flexible nature of the waveguide material makes this process ideal for a potential wearable optical sensor. PMID:22171151

  9. Subwavelength-grating-assisted broadband polarization-independent directional coupler.

    PubMed

    Liu, Lu; Deng, Qingzhong; Zhou, Zhiping

    2016-04-01

    This Letter presents both numerical and experimental results of a polarization-independent directional coupler based on slot waveguides with a subwavelength grating. The measured coupling efficiency is 97.4% for TE and 96.7% for TM polarization at a wavelength of 1550 nm. Further analysis shows that the proposed subwavelength grating directional coupler has a fabrication tolerance of ±20  nm for the grating structure and that the coupling efficiencies for the two polarizations are both higher than -0.5  dB (∼89%), exceeding the entire C-band (1525-1570 nm) experimentally. PMID:27192309

  10. Fiber optic data bus using Frequency Division Multiplexing (FDM) and an asymmetric coupler

    NASA Technical Reports Server (NTRS)

    Zanger, M.; Webster, L.

    1984-01-01

    A fiber optic data bus, using frequency division multiplexing (FDM) is discussed. The use of FDM is motivated by the need to avoid central control of the bus operation. A major difficulty of such a data bus is introduced by the couplers. An efficient low loss access coupler with an asymmetric structure is presented, and manufacturing processes for the coupler are proposed.

  11. High performance computing and communications program

    NASA Technical Reports Server (NTRS)

    Holcomb, Lee

    1992-01-01

    A review of the High Performance Computing and Communications (HPCC) program is provided in vugraph format. The goals and objectives of this federal program are as follows: extend U.S. leadership in high performance computing and computer communications; disseminate the technologies to speed innovation and to serve national goals; and spur gains in industrial competitiveness by making high performance computing integral to design and production.

  12. Statistical properties of high performance cesium standards

    NASA Technical Reports Server (NTRS)

    Percival, D. B.

    1973-01-01

    The intermediate term frequency stability of a group of new high-performance cesium beam tubes at the U.S. Naval Observatory were analyzed from two viewpoints: (1) by comparison of the high-performance standards to the MEAN(USNO) time scale and (2) by intercomparisons among the standards themselves. For sampling times up to 5 days, the frequency stability of the high-performance units shows significant improvement over older commercial cesium beam standards.

  13. A History of the Chemical Innovations in Silver-Halide Materials for Color PhotographyII. Color-Forming Development, Part 5. Coupler Innovations after the 1970's—Two-Equivalent Coupler and DIR Coupler

    NASA Astrophysics Data System (ADS)

    Oishi, Yasushi

    After the 1970's on, several manufacturers including Fuji Film, Konica and Agfa-Gevaert participated in innovating color photographic materials by adding their own coupler chemistry to the technological architecture built by Kodak before then. One area of their major advances was development of the couplers having a coupling-off organic group. One of their functional forms was two-equivalent coupler which made the dye-forming process efficient and made the photosensitive layers slim. And another was DIR coupler which improved dramatically the image quality of color negative materials. In this paper a historical overview of these innovations is constructed from the technical documents, mainly patents.

  14. Method of making a high performance ultracapacitor

    SciTech Connect

    Farahmandi, C.J.; Dispennette, J.M.

    2000-05-09

    A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg.

  15. Method of making a high performance ultracapacitor

    DOEpatents

    Farahmandi, C. Joseph; Dispennette, John M.

    2000-07-26

    A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg.

  16. High performance carbon nanocomposites for ultracapacitors

    DOEpatents

    Lu, Wen

    2012-10-02

    The present invention relates to composite electrodes for electrochemical devices, particularly to carbon nanotube composite electrodes for high performance electrochemical devices, such as ultracapacitors.

  17. Common Factors of High Performance Teams

    ERIC Educational Resources Information Center

    Jackson, Bruce; Madsen, Susan R.

    2005-01-01

    Utilization of work teams is now wide spread in all types of organizations throughout the world. However, an understanding of the important factors common to high performance teams is rare. The purpose of this content analysis is to explore the literature and propose findings related to high performance teams. These include definition and types,…

  18. High Performance Work Systems and Firm Performance.

    ERIC Educational Resources Information Center

    Kling, Jeffrey

    1995-01-01

    A review of 17 studies of high-performance work systems concludes that benefits of employee involvement, skill training, and other high-performance work practices tend to be greater when new methods are adopted as part of a consistent whole. (Author)

  19. Sustaining High Performance in Bad Times.

    ERIC Educational Resources Information Center

    Bassi, Laurie J.; Van Buren, Mark A.

    1997-01-01

    Summarizes the results of the American Society for Training and Development Human Resource and Performance Management Survey of 1996 that examined the performance outcomes of downsizing and high performance work systems, explored the relationship between high performance work systems and downsizing, and asked whether some downsizing practices were…

  20. High Performance Work Practices and Firm Performance.

    ERIC Educational Resources Information Center

    Department of Labor, Washington, DC. Office of the American Workplace.

    A literature survey established that a substantial amount of research has been conducted on the relationship between productivity and the following specific high performance work practices: employee involvement in decision making, compensation linked to firm or worker performance, and training. According to these studies, high performance work…

  1. An Associate Degree in High Performance Manufacturing.

    ERIC Educational Resources Information Center

    Packer, Arnold

    In order for more individuals to enter higher paying jobs, employers must create a sufficient number of high-performance positions (the demand side), and workers must acquire the skills needed to perform in these restructured workplaces (the supply side). Creating an associate degree in High Performance Manufacturing (HPM) will help address four…

  2. Interferometer using a 3 × 3 coupler and Faraday mirrors

    NASA Astrophysics Data System (ADS)

    Breguet, J.; Gisin, N.

    1995-06-01

    A new interferometric setup using a 3 \\times 3 coupler and two Faraday mirrors is presented. It has the advantages of being built only with passive components, of freedom from the polarization fading problem, and of operation with a LED. It is well suited for sensing time-dependent signals and does not depend on reciprocal or nonreciprocal constant perturbations.

  3. Interferometer using a 3 x 3 coupler and Faraday mirrors.

    PubMed

    Breguet, J; Gisin, N

    1995-06-15

    A new interferometric setup using a 3 x 3 coupler and two Faraday mirrors is presented. It has the advantages of being built only with passive components, of freedom from the polarization fading problem, and of operation with a LED. It is well suited for sensing time-dependent signals and does not depend on reciprocal or nonreciprocal constant perturbations. PMID:19862044

  4. Investigations on 4x4 polymer couplers for airborne environment

    NASA Astrophysics Data System (ADS)

    Klotzbuecher, Thomas; Sprzagala, M.; Koch, Anne; Teubner, Ulrich

    2004-09-01

    Due to the potential of high data rates up to several Gb/s, low electromagnetic interference sensitivity and weight reduction capabilities, in future, optical data transmission will become standard in airplanes. The requirements on the necessary optical components that have to be operated in airborne environment in general are extremely high. In addition, airframe manufacturers are interested in low cost components. An example for such an optical component is a star coupler for data distribution, in particular, a device made on base of polymers. The applicability of such 4x4 polymer star couplers under extreme environmental conditions was investigated. The investigations were made at temperatures from -40 to +80 °C and up to 98 % humidity. Different types of housings were tested (polymer, metal, ceramic). It was found that housing of the polymer couplers is required necessarily, since non-housed components exhibit a large insertion loss increase of up to 0.5 dB during temperature variation. Best results were achieved with metal or ceramic housings exhibiting a maximum insertion loss increase of approximately 0.1 dB. However, due to a large difference of thermal expansion coefficients of filling and housing material, respectively, ceramic housings mechanically failed (crack formation) and thus metal housings are first choice. The results were also compared to those achieved for commercial 4x4 multimode couplers made of glass and based on fused bi-conical taper technology.

  5. A HIGH POWER RF COUPLER DESIGN FOR MUON COOLING RF CAVITIES.

    SciTech Connect

    CORLETT,J.; LI,DERUN; RIMMER,R.; HOLTKAMP,N.; MORETTI,A.; KIRK,H.G.

    1999-03-29

    We present a high power RF coupler design for an interleaved {pi}/2 805 MHz standing wave accelerating structure proposed for an muon cooling experiment at FNAL. The coupler, in its simplest form, is a rectangular waveguide directly connected to an accelerating Cell through an open slot on the cavity side-wall or end-plates. Two of such couplers are needed to feed the interleaved cavities. Current high power RF test requires the coupler to be at critical coupling. Numerical simulations on the coupler designs using MAFIA will be presented.

  6. Design, performance and production of the Fermilab TESLA RF input couplers

    SciTech Connect

    Champion, M.

    1996-10-01

    The TeV Energy Superconducting Linear Accelerator (TESLA) requires as one of its technical components a radiofrequency (rf) input coupler that transfers 1.3 GHz rf energy from the rf distribution system to a nine-cell superconducting accelerating cavity operating at a temperature of 1.8 K. The input coupler design is driven by numerous design criteria, which result in a rather complicated implementation. The production of twelve input couplers for the TESLA Test Facility (TTF) is underway at Fermilab, with the first two couplers having been delivered late in 1995. This paper discusses the Fermilab TESLA rf input coupler design, recent test results, and production issues.

  7. High performance image processing of SPRINT

    SciTech Connect

    DeGroot, T.

    1994-11-15

    This talk will describe computed tomography (CT) reconstruction using filtered back-projection on SPRINT parallel computers. CT is a computationally intensive task, typically requiring several minutes to reconstruct a 512x512 image. SPRINT and other parallel computers can be applied to CT reconstruction to reduce computation time from minutes to seconds. SPRINT is a family of massively parallel computers developed at LLNL. SPRINT-2.5 is a 128-node multiprocessor whose performance can exceed twice that of a Cray-Y/MP. SPRINT-3 will be 10 times faster. Described will be the parallel algorithms for filtered back-projection and their execution on SPRINT parallel computers.

  8. Parallel computing works

    SciTech Connect

    Not Available

    1991-10-23

    An account of the Caltech Concurrent Computation Program (C{sup 3}P), a five year project that focused on answering the question: Can parallel computers be used to do large-scale scientific computations '' As the title indicates, the question is answered in the affirmative, by implementing numerous scientific applications on real parallel computers and doing computations that produced new scientific results. In the process of doing so, C{sup 3}P helped design and build several new computers, designed and implemented basic system software, developed algorithms for frequently used mathematical computations on massively parallel machines, devised performance models and measured the performance of many computers, and created a high performance computing facility based exclusively on parallel computers. While the initial focus of C{sup 3}P was the hypercube architecture developed by C. Seitz, many of the methods developed and lessons learned have been applied successfully on other massively parallel architectures.

  9. Implementing High Performance Remote Method Invocation in CCA

    SciTech Connect

    Yin, Jian; Agarwal, Khushbu; Krishnan, Manoj Kumar; Chavarría-Miranda, Daniel; Gorton, Ian; Epperly, Thomas G.

    2011-09-30

    We report our effort in engineering a high performance remote method invocation (RMI) mechanism for the Common Component Architecture (CCA). This mechanism provides a highly efficient and easy-to-use mechanism for distributed computing in CCA, enabling CCA applications to effectively leverage parallel systems to accelerate computations. This work is built on the previous work of Babel RMI. Babel is a high performance language interoperability tool that is used in CCA for scientific application writers to share, reuse, and compose applications from software components written in different programming languages. Babel provides a transparent and flexible RMI framework for distributed computing. However, the existing Babel RMI implementation is built on top of TCP and does not provide the level of performance required to distribute fine-grained tasks. We observed that the main reason the TCP based RMI does not perform well is because it does not utilize the high performance interconnect hardware on a cluster efficiently. We have implemented a high performance RMI protocol, HPCRMI. HPCRMI achieves low latency by building on top of a low-level portable communication library, Aggregated Remote Message Copy Interface (ARMCI), and minimizing communication for each RMI call. Our design allows a RMI operation to be completed by only two RDMA operations. We also aggressively optimize our system to reduce copying. In this paper, we discuss the design and our experimental evaluation of this protocol. Our experimental results show that our protocol can improve RMI performance by an order of magnitude.

  10. Tunable dual-parallel Mach-Zehnder modulator with ultra linearity and high tolerance

    NASA Astrophysics Data System (ADS)

    Yue, Peng; Mao, Bomin; Hou, Fanfan; Liu, Zengji

    2015-06-01

    An electro-optic modulator with excellent linearity and high tolerance can be crucial for optimizing the performance of optical communication systems by improving modulation efficiency. In this paper, we propose a novel dual-parallel Mach-Zehnder modulator with three Multimode Interference couplers (MMI-DPMZM) consisting of a reconfigurable type and two 3 dB ones. The structure can maintain a high dynamic range over a wide operating range and is highly tolerant of manufacturing errors because the MMI couplers split the light precisely and flexibly. When the value of the radio frequency voltage splitting ratio deviates from its optimum value within ?, the Spurious-Free Dynamic Range can be maintained above 104.00 dB ? Hz? through the adjustment of the tunable MMI coupler. Further analysis of the effects of modern MMI couplers' fabrication errors demonstrates the dynamic range can still be 104.10 dB ? Hz?.

  11. Strategy Guideline: High Performance Residential Lighting

    SciTech Connect

    Holton, J.

    2012-02-01

    The Strategy Guideline: High Performance Residential Lighting has been developed to provide a tool for the understanding and application of high performance lighting in the home. The high performance lighting strategies featured in this guide are drawn from recent advances in commercial lighting for application to typical spaces found in residential buildings. This guide offers strategies to greatly reduce lighting energy use through the application of high quality fluorescent and light emitting diode (LED) technologies. It is important to note that these strategies not only save energy in the home but also serve to satisfy the homeowner's expectations for high quality lighting.

  12. Radio Synthesis Imaging - A High Performance Computing and Communications Project

    NASA Astrophysics Data System (ADS)

    Crutcher, Richard M.

    The National Science Foundation has funded a five-year High Performance Computing and Communications project at the National Center for Supercomputing Applications (NCSA) for the direct implementation of several of the computing recommendations of the Astronomy and Astrophysics Survey Committee (the "Bahcall report"). This paper is a summary of the project goals and a progress report. The project will implement a prototype of the next generation of astronomical telescope systems - remotely located telescopes connected by high-speed networks to very high performance, scalable architecture computers and on-line data archives, which are accessed by astronomers over Gbit/sec networks. Specifically, a data link has been installed between the BIMA millimeter-wave synthesis array at Hat Creek, California and NCSA at Urbana, Illinois for real-time transmission of data to NCSA. Data are automatically archived, and may be browsed and retrieved by astronomers using the NCSA Mosaic software. In addition, an on-line digital library of processed images will be established. BIMA data will be processed on a very high performance distributed computing system, with I/O, user interface, and most of the software system running on the NCSA Convex C3880 supercomputer or Silicon Graphics Onyx workstations connected by HiPPI to the high performance, massively parallel Thinking Machines Corporation CM-5. The very computationally intensive algorithms for calibration and imaging of radio synthesis array observations will be optimized for the CM-5 and new algorithms which utilize the massively parallel architecture will be developed. Code running simultaneously on the distributed computers will communicate using the Data Transport Mechanism developed by NCSA. The project will also use the BLANCA Gbit/s testbed network between Urbana and Madison, Wisconsin to connect an Onyx workstation in the University of Wisconsin Astronomy Department to the NCSA CM-5, for development of long

  13. IBM SP high-performance networking with a GRF.

    SciTech Connect

    Navarro, J.P.

    1999-05-27

    Increasing use of highly distributed applications, demand for faster data exchange, and highly parallel applications can push the limits of conventional external networking for IBM SP sites. In technical computing applications we have observed a growing use of a pipeline of hosts and networks collaborating to collect, process, and visualize large amounts of realtime data. The GRF, a high-performance IP switch from Ascend and IBM, is the first backbone network switch to offer a media card that can directly connect to an SP Switch. This enables switch attached hosts in an SP complex to communicate at near SP Switch speeds with other GRF attached hosts and networks.

  14. High-performance computing in structural mechanics and engineering

    SciTech Connect

    Adeli, H.; Kamat, M.P.; Kulkarni, G.; Vanluchene, R.D. Georgia Inst. of Technology, Atlanta Montana State Univ., Bozeman )

    1993-07-01

    Recent advances in computer hardware and software have made multiprocessing a viable and attractive technology. This paper reviews high-performance computing methods in structural mechanics and engineering through the use of a new generation of multiprocessor computers. The paper presents an overview of vector pipelining, performance metrics for parallel and vector computers, programming languages, and general programming considerations. Recent developments in the application of concurrent processing techniques to the solution of structural mechanics and engineering problems are reviewed, with special emphasis on linear structural analysis, nonlinear structural analysis, transient structural analysis, dynamics of multibody flexible systems, and structural optimization. 64 refs.

  15. High Performance Computing with Harness over InfiniBand

    SciTech Connect

    Valentini, Alessandro; Di Biagio, Christian; Batino, Fabrizio; Pennella, Guido; Palma, Fabrizio; Engelmann, Christian

    2009-01-01

    Harness is an adaptable and plug-in-based middleware framework able to support distributed parallel computing. By now, it is based on the Ethernet protocol which cannot guarantee high performance throughput and real time (determinism) performance. During last years, both, the research and industry environments have developed new network architectures (InfiniBand, Myrinet, iWARP, etc.) to avoid those limits. This paper concerns the integration between Harness and InfiniBand focusing on two solutions: IP over InfiniBand (IPoIB) and Socket Direct Protocol (SDP) technology. They allow the Harness middleware to take advantage of the enhanced features provided by the InfiniBand Architecture.

  16. Challenges for high-performance networking for exascale computing.

    SciTech Connect

    Barrett, Brian W.; Hemmert, K. Scott; Underwood, Keith Douglas; Brightwell, Ronald Brian

    2010-05-01

    Achieving the next three orders of magnitude performance increase to move from petascale to exascale computing will require a significant advancements in several fundamental areas. Recent studies have outlined many of the challenges in hardware and software that will be needed. In this paper, we examine these challenges with respect to high-performance networking. We describe the repercussions of anticipated changes to computing and networking hardware and discuss the impact that alternative parallel programming models will have on the network software stack. We also present some ideas on possible approaches that address some of these challenges.

  17. Concurrent file operations in a high performance FORTRAN

    NASA Technical Reports Server (NTRS)

    Brezany, Peter; Gerndt, Michael; Mehrotra, Piyush; Zima, Hans

    1992-01-01

    Distributed memory multiprocessor systems can provide the computing power necessary for large scale scientific applications. A critical performance issue for a number of these applications is the efficient transfer of data to secondary storage. Recently several research groups have proposed FORTRAN language extensions for exploiting the data parallelism of such scientific codes on distributed memory architectures. However, few of these high performance FORTRAN's provide appropriate constructs for controlling the use of the parallel I/O capabilities of modern multiprocessing machines. In this paper, we propose constructs to specify I/O operations for distributed data structures in the context of Vienna Fortran. These operations can be used by the programmer to provide information which can help the compiler and runtime environment make the most efficient use of the I/O subsystem.

  18. Productive high-performance software for OpenCL devices

    NASA Astrophysics Data System (ADS)

    Melonakos, John M.; Yalamanchili, Pavan; McClanahan, Chris; Arshad, Umar; Landes, Michael; Jamboti, Shivapriya; Joshi, Abhijit; Mohammed, Shehzan; Spafford, Kyle; Venugopalakrishnan, Vishwanath; Malcolm, James

    2013-05-01

    Over the last three decades, CPUs have continued to produce large performance improvements from one generation to the next. However, CPUs have recently hit a performance wall and need parallel computing to move forward. Parallel computing over the next decade will become increasingly defined by heterogeneous computing, involving the use of accelerators in addition to CPUs to get computational tasks done. In order to use an accelerator, software changes must be made. Regular x86-based compilers cannot compile code to run on accelerators without these needed changes. The amount of software change required varies depending upon the availability of and reliance upon software tools that increase performance and productivity. Writing software that leverages the best parallel computing hardware, adapts well to the rapid pace of hardware updates, and minimizes developer muscle is the industry's goal. OpenCL is the standard around which developers are able to achieve parallel performance. OpenCL itself is too difficult to program to receive general adoptions, but productive high-performing software libraries are becoming increasingly popular and capable in delivering lasting value to user applications.

  19. High-performance simulations for atmospheric pressure plasma reactor

    NASA Astrophysics Data System (ADS)

    Chugunov, Svyatoslav

    Plasma-assisted processing and deposition of materials is an important component of modern industrial applications, with plasma reactors sharing 30% to 40% of manufacturing steps in microelectronics production. Development of new flexible electronics increases demands for efficient high-throughput deposition methods and roll-to-roll processing of materials. The current work represents an attempt of practical design and numerical modeling of a plasma enhanced chemical vapor deposition system. The system utilizes plasma at standard pressure and temperature to activate a chemical precursor for protective coatings. A specially designed linear plasma head, that consists of two parallel plates with electrodes placed in the parallel arrangement, is used to resolve clogging issues of currently available commercial plasma heads, as well as to increase the flow-rate of the processed chemicals and to enhance the uniformity of the deposition. A test system is build and discussed in this work. In order to improve operating conditions of the setup and quality of the deposited material, we perform numerical modeling of the plasma system. The theoretical and numerical models presented in this work comprehensively describe plasma generation, recombination, and advection in a channel of arbitrary geometry. Number density of plasma species, their energy content, electric field, and rate parameters are accurately calculated and analyzed in this work. Some interesting engineering outcomes are discussed with a connection to the proposed setup. The numerical model is implemented with the help of high-performance parallel technique and evaluated at a cluster for parallel calculations. A typical performance increase, calculation speed-up, parallel fraction of the code and overall efficiency of the parallel implementation are discussed in details.

  20. Semi-reciprocal polarization maintaining fibre coupler with distinctive transmission characteristics

    PubMed Central

    Wang, Xinyue; Thomas, Freya; Wang, Ziyu

    2015-01-01

    Optical couplers are very important devices in optical communication systems and optical sensor systems. Several types of optical couplers with different materials or different transmission characteristics have been reported. Here we propose a semi-reciprocal polarization maintaining fibre coupler with unique transmission characteristics, which is distinct from conventional polarization maintaining fibre couplers and polarization beam splitters, and investigate the characteristics of the coupler theoretically and experimentally. The experimental results show that for circularly and elliptically polarized input light, the proposed coupler will act both as an in-line polariser and a conventional polarization maintaining fibre coupler. The output polarization extinction ratio of the transmission arm is 31.79 dB at a centre wavelength of 841 nm. For linearly polarized input light, the coupler will merely act as a conventional 3 dB polarization maintaining fibre coupler. The unique features of the proposed coupler enables the removal of polarisers from optical sensor systems and coherent optical communication systems, and reduces the insertion loss and production cost of the optical path. Therefore there is wide application for this device in optical sensor systems and optical communication systems. PMID:26611837

  1. Semi-reciprocal polarization maintaining fibre coupler with distinctive transmission characteristics.

    PubMed

    Wang, Xinyue; Thomas, Freya; Wang, Ziyu

    2015-01-01

    Optical couplers are very important devices in optical communication systems and optical sensor systems. Several types of optical couplers with different materials or different transmission characteristics have been reported. Here we propose a semi-reciprocal polarization maintaining fibre coupler with unique transmission characteristics, which is distinct from conventional polarization maintaining fibre couplers and polarization beam splitters, and investigate the characteristics of the coupler theoretically and experimentally. The experimental results show that for circularly and elliptically polarized input light, the proposed coupler will act both as an in-line polariser and a conventional polarization maintaining fibre coupler. The output polarization extinction ratio of the transmission arm is 31.79 dB at a centre wavelength of 841 nm. For linearly polarized input light, the coupler will merely act as a conventional 3 dB polarization maintaining fibre coupler. The unique features of the proposed coupler enables the removal of polarisers from optical sensor systems and coherent optical communication systems, and reduces the insertion loss and production cost of the optical path. Therefore there is wide application for this device in optical sensor systems and optical communication systems. PMID:26611837

  2. Semi-reciprocal polarization maintaining fibre coupler with distinctive transmission characteristics

    NASA Astrophysics Data System (ADS)

    Wang, Xinyue; Thomas, Freya; Wang, Ziyu

    2015-11-01

    Optical couplers are very important devices in optical communication systems and optical sensor systems. Several types of optical couplers with different materials or different transmission characteristics have been reported. Here we propose a semi-reciprocal polarization maintaining fibre coupler with unique transmission characteristics, which is distinct from conventional polarization maintaining fibre couplers and polarization beam splitters, and investigate the characteristics of the coupler theoretically and experimentally. The experimental results show that for circularly and elliptically polarized input light, the proposed coupler will act both as an in-line polariser and a conventional polarization maintaining fibre coupler. The output polarization extinction ratio of the transmission arm is 31.79 dB at a centre wavelength of 841 nm. For linearly polarized input light, the coupler will merely act as a conventional 3 dB polarization maintaining fibre coupler. The unique features of the proposed coupler enables the removal of polarisers from optical sensor systems and coherent optical communication systems, and reduces the insertion loss and production cost of the optical path. Therefore there is wide application for this device in optical sensor systems and optical communication systems.

  3. Beam Fields in an Integrated Cavity, Coupler and Window Configuration

    SciTech Connect

    Weathersby, Stephen; Novokhatski, Alexander; /SLAC

    2010-02-10

    In a multi-bunch high current storage ring, beam generated fields couple strongly into the RF cavity coupler structure when beam arrival times are in resonance with cavity fields. In this study the integrated effect of beam fields over several thousand RF periods is simulated for the complete cavity, coupler, window and waveguide system of the PEP-II B-factory storage ring collider. We show that the beam generated fields at frequencies corresponding to several bunch spacings for this case gives rise to high field strength near the ceramic window which could limit the performance of future high current storage rings such as PEP-X or Super B-factories.

  4. GaN directional couplers for integrated quantum photonics

    SciTech Connect

    Zhang Yanfeng; McKnight, Loyd; Watson, Ian M.; Gu, Erdan; Calvez, Stephane; Dawson, Martin D.; Engin, Erman; Cryan, Martin J.; Thompson, Mark G.; O'Brien, Jeremy L.

    2011-10-17

    Large cross-section GaN waveguides are proposed as a suitable architecture to achieve integrated quantum photonic circuits. Directional couplers with this geometry have been designed with aid of the beam propagation method and fabricated using inductively coupled plasma etching. Scanning electron microscopy inspection shows high quality facets for end coupling and a well defined gap between rib pairs in the coupling region. Optical characterization at 800 nm shows single-mode operation and coupling-length-dependent splitting ratios. Two photon interference of degenerate photon pairs has been observed in the directional coupler by measurement of the Hong-Ou-Mandel dip [C. K. Hong, et al., Phys. Rev. Lett. 59, 2044 (1987)] with 96% visibility.

  5. Coupled resonator filter with single-layer acoustic coupler.

    PubMed

    Jamneala, Tiberiu; Small, Martha; Ruby, Rich; Larson, John D

    2008-10-01

    We discuss the operation of novel coupled-resonator filters with single-layer acoustic couplers. Our analysis employs the physical Mason model for acoustic resonators. Their simpler fabrication process is counterbalanced by the high acoustic attenuation of suitable coupler materials. At high levels of attenuation, both the phase and the acoustic impedance must be treated as complex quantities to accurately predict the filter insertion loss. We demonstrate that the typically poor near-band rejection of coupled resonator filters can be improved at the die level by connecting a small capacitance between the input and output of the filter to produce a pair of tunable transmission minima. We make use of these theoretical findings to fabricate coupled resonators filters operating at 2.45 GHz. PMID:18986880

  6. Terahertz quantum well photodetectors with reflection-grating couplers

    SciTech Connect

    Zhang, R.; Fu, Z. L.; Gu, L. L.; Guo, X. G.; Cao, J. C.

    2014-12-08

    The design, fabrication, and characterization of terahertz (THz) quantum well photodetectors with one-dimensional reflection-grating coupler are presented. It is found that the reflection gratings could effectively couple the THz waves normally incident to the device. Compared with the 45-degree facet sample, the peak responsivity of this grating-coupled detector is enhanced by over 20%. The effects of the gratings on the photocurrent spectra are also analyzed.

  7. Challenges in building high performance geoscientific spatial data infrastructures

    NASA Astrophysics Data System (ADS)

    Dubros, Fabrice; Tellez-Arenas, Agnes; Boulahya, Faiza; Quique, Robin; Le Cozanne, Goneri; Aochi, Hideo

    2016-04-01

    One of the main challenges in Geosciences is to deal with both the huge amounts of data available nowadays and the increasing need for fast and accurate analysis. On one hand, computer aided decision support systems remain a major tool for quick assessment of natural hazards and disasters. High performance computing lies at the heart of such systems by providing the required processing capabilities for large three-dimensional time-dependent datasets. On the other hand, information from Earth observation systems at different scales is routinely collected to improve the reliability of numerical models. Therefore, various efforts have been devoted to design scalable architectures dedicated to the management of these data sets (Copernicus, EarthCube, EPOS). Indeed, standard data architectures suffer from a lack of control over data movement. This situation prevents the efficient exploitation of parallel computing architectures as the cost for data movement has become dominant. In this work, we introduce a scalable architecture that relies on high performance components. We discuss several issues such as three-dimensional data management, complex scientific workflows and the integration of high performance computing infrastructures. We illustrate the use of such architectures, mainly using off-the-shelf components, in the framework of both coastal flooding assessments and earthquake early warning systems.

  8. Efficient Coupler for a Bessel Beam Dispersive Element

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy; Iltchenko, Vladimir; Matsko, Andrey; Le, Thanh; Yu, nan; Maleki, Lute

    2008-01-01

    A document discusses overcoming efficient optical coupling to high orbital momentum modes by slightly bending the taper dispersive element. This little shape distortion is not enough to scramble the modes, but it allows the use of regular, free-beam prism coupling, fiber coupling, or planar fiber on-chip coupling with, ultimately, 100 percent efficiency. The Bessel-beam waveguide is bent near the contact with the coupler, or a curved coupler is used. In this case, every Bessel-beam mode can be successfully coupled to a collimated Gaussian beam. Recently developed Bessel-beam waveguides allow long optical delay and very high dispersion. Delay values may vary from nanoseconds to microseconds, and dispersion promises to be at 100 s/nm. Optical setup consisted of a red laser, an anamorphic prism pair, two prism couplers, and a bent, single-mode fiber attached to prisms. The coupling rate increased substantially and corresponded to the value determined by the anamorphic prism pair.

  9. Inductive coupler for downhole components and method for making same

    DOEpatents

    Hall, David R.; Hall, Jr., H. Tracy; Pixton, David S.; Dahlgren, Scott; Briscoe, Michael A.; Sneddon, Cameron; Fox, Joe

    2006-05-09

    The present invention includes a method of making an inductive coupler for downhole components. The method includes providing an annular housing, preferably made of steel, the housing having a recess. A conductor, preferably an insulated wire, is also provided along with a plurality of generally U-shaped magnetically conducting, electrically insulating (MCEI) segments. Preferably, the MCEI segments comprise ferrite. An assembly is formed by placing the plurality of MCEI segments within the recess in the annular housing. The segments are aligned to form a generally circular trough. A first portion of the conductor is placed within the circular trough. This assembly is consolidated with a meltable polymer which fills spaces between the segments, annular housing and the first portion of the conductor. The invention also includes an inductive coupler including an annular housing having a recess defined by a bottom portion and two opposing side wall portions. At least one side wall portion includes a lip extending toward but not reaching the other side wall portion. A plurality of generally U-shaped MCEI segments, preferably comprised of ferrite, are disposed in the recess and aligned so as to form a circular trough. The coupler further includes a conductor disposed within the circular trough and a polymer filling spaces between the segments, the annular housing and the conductor.

  10. State of the Art Power Couplers for Superconducting RF Cavities

    SciTech Connect

    Isidoro Campisi

    2002-08-01

    Simulations are now routinely performed that allow the prediction of electromagnetic, multipacting, thermal, and mechanical properties of couplers. From these studies, better designs have been conceived which can minimize potential problems ahead of construction. Judicious use of materials and the implementation of clean practices and of careful conditioning have gradually increased the power levels at which couplers can safely operate. Machine operation at hundreds of kilowatts has been achieved in CW at KEK and Cornell, and in a pulsed mode at the TESLA Test Facility (TTF). Test stand operations in CW at the megawatt level (Accelerator for the Production of Tritium) and in pulse mode at a peak power of 2 MW (Spallation Neutron Source, TTF version II) have been achieved. The recent progress indicates that the understanding of the behavior of fundamental power couplers is rapidly increasing and that optimal designs are being developed which will allow in the future to attain routine attainment of the megawatt power levels necessary for high-beam-power machines under construction and under study.

  11. Design of the spoke cavity ED&D input coupler.

    SciTech Connect

    Schmierer, E. N.; Chan, K. D.; Gentzlinger, R.C.; Haynes, W. B.; Krawczyk, F. L.; Montoya, D. I.; Roybal, P. L.; Schrage, D. L.; Tajima, T.

    2001-01-01

    The current design of the Accelerator Driven Test Facility (ADTF) accelerator contains multiple {beta}, superconducting, resonant cavities. Spoke-type resonators ({beta} = 0.175 and {beta} = 0.34) are proposed for the low energy linac immediately following the radio frequency quadrupole. A continuous wave power requirement of 8.5 - 211.8 kW, 350 MHz has been established for the input couplers of these spoke cavities. The coupler design approach was to have a single input coupler design for beam currents of 13.3 mA and 100 mA and both cavity {beta}'s. The baseline design consists of a half-height WR2300 waveguide section merged with a shorted coaxial conductor. At the transition is a 4.8-mm thick cylindrical ceramic window creating the air/vacuum barrier. The coax is 103-mm inner diameter, 75 Ohm. The coax extends from the short through the waveguide and terminates with an antenna tip in the sidewall of the cavity. A full diameter pumping port is located in the quarter-wave stub to facilitate good vacuum. The coaxial geometry chosen was based on multipacting and thermal design considerations. The coupling coefficient is adjusted by statically adjusting the outer conductor length. The RF-physics, thermal, vacuum, and structural design considerations will be discussed in this paper, in addition to future room temperature testing plans.

  12. High performance bio-integrated devices

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Hyeong; Lee, Jongha; Park, Minjoon

    2014-06-01

    In recent years, personalized electronics for medical applications, particularly, have attracted much attention with the rise of smartphones because the coupling of such devices and smartphones enables the continuous health-monitoring in patients' daily life. Especially, it is expected that the high performance biomedical electronics integrated with the human body can open new opportunities in the ubiquitous healthcare. However, the mechanical and geometrical constraints inherent in all standard forms of high performance rigid wafer-based electronics raise unique integration challenges with biotic entities. Here, we describe materials and design constructs for high performance skin-mountable bio-integrated electronic devices, which incorporate arrays of single crystalline inorganic nanomembranes. The resulting electronic devices include flexible and stretchable electrophysiology electrodes and sensors coupled with active electronic components. These advances in bio-integrated systems create new directions in the personalized health monitoring and/or human-machine interfaces.

  13. Strategy Guideline. Partnering for High Performance Homes

    SciTech Connect

    Prahl, Duncan

    2013-01-01

    High performance houses require a high degree of coordination and have significant interdependencies between various systems in order to perform properly, meet customer expectations, and minimize risks for the builder. Responsibility for the key performance attributes is shared across the project team and can be well coordinated through advanced partnering strategies. For high performance homes, traditional partnerships need to be matured to the next level and be expanded to all members of the project team including trades, suppliers, manufacturers, HERS raters, designers, architects, and building officials as appropriate. This guide is intended for use by all parties associated in the design and construction of high performance homes. It serves as a starting point and features initial tools and resources for teams to collaborate to continually improve the energy efficiency and durability of new houses.

  14. Dinosaurs can fly -- High performance refining

    SciTech Connect

    Treat, J.E.

    1995-09-01

    High performance refining requires that one develop a winning strategy based on a clear understanding of one`s position in one`s company`s value chain; one`s competitive position in the products markets one serves; and the most likely drivers and direction of future market forces. The author discussed all three points, then described measuring performance of the company. To become a true high performance refiner often involves redesigning the organization as well as the business processes. The author discusses such redesigning. The paper summarizes ten rules to follow to achieve high performance: listen to the market; optimize; organize around asset or area teams; trust the operators; stay flexible; source strategically; all maintenance is not equal; energy is not free; build project discipline; and measure and reward performance. The paper then discusses the constraints to the implementation of change.

  15. Tapered acoustical directional couplers for integrated acousto-optical mode converters with weighted coupling

    NASA Astrophysics Data System (ADS)

    Herrmann, Harald; Rust, Ulrich; Schafer, Klaus

    1995-03-01

    Weighted coupling for strong sidelobe suppression of integrated acoustooptical mode converters in LiNbO3 using acoustical directional couplers has been studied theoretically and experimentally. A parameter free model for the propagation of surface acoustic waves in guiding structures has been developed based on a step-like variation of the acoustic velocity. Comparisons of theoretical results with experimental ones for acoustic waveguides and directional coupler structures confirm the applicability of the model. A coupled mode description of the acousto-optical polarization conversion in converters with acoustical directional couplers has been developed and applied to several tapered acoustical directional couplers. The model reveals that the conversion characteristics are usually strongly asymmetric. If the directional coupler is appropriately designed, a sidelobe suppression of about 30 dB can be achieved. First experimental results with tapered directional couplers confirm within some limits the theoretical predictions.

  16. High performance computing at Sandia National Labs

    SciTech Connect

    Cahoon, R.M.; Noe, J.P.; Vandevender, W.H.

    1995-10-01

    Sandia`s High Performance Computing Environment requires a hierarchy of resources ranging from desktop, to department, to centralized, and finally to very high-end corporate resources capable of teraflop performance linked via high-capacity Asynchronous Transfer Mode (ATM) networks. The mission of the Scientific Computing Systems Department is to provide the support infrastructure for an integrated corporate scientific computing environment that will meet Sandia`s needs in high-performance and midrange computing, network storage, operational support tools, and systems management. This paper describes current efforts at SNL/NM to expand and modernize centralized computing resources in support of this mission.

  17. Opportunities and challenges of high-performance computing in chemistry

    SciTech Connect

    Guest, M.F.; Kendall, R.A.; Nichols, J.A.

    1995-06-01

    The field of high-performance computing is developing at an extremely rapid pace. Massively parallel computers offering orders of magnitude increase in performance are under development by all the major computer vendors. Many sites now have production facilities that include massively parallel hardware. Molecular modeling methodologies (both quantum and classical) are also advancing at a brisk pace. The transition of molecular modeling software to a massively parallel computing environment offers many exciting opportunities, such as the accurate treatment of larger, more complex molecular systems in routine fashion, and a viable, cost-effective route to study physical, biological, and chemical `grand challenge` problems that are impractical on traditional vector supercomputers. This will have a broad effect on all areas of basic chemical science at academic research institutions and chemical, petroleum, and pharmaceutical industries in the United States, as well as chemical waste and environmental remediation processes. But, this transition also poses significant challenges: architectural issues (SIMD, MIMD, local memory, global memory, etc.) remain poorly understood and software development tools (compilers, debuggers, performance monitors, etc.) are not well developed. In addition, researchers that understand and wish to pursue the benefits offered by massively parallel computing are often hindered by lack of expertise, hardware, and/or information at their site. A conference and workshop organized to focus on these issues was held at the National Institute of Health, Bethesda, Maryland (February 1993). This report is the culmination of the organized workshop. The main conclusion: a drastic acceleration in the present rate of progress is required for the chemistry community to be positioned to exploit fully the emerging class of Teraflop computers, even allowing for the significant work to date by the community in developing software for parallel architectures.

  18. Design and fabrication of multimode interference couplers based on digital micro-mirror system

    NASA Astrophysics Data System (ADS)

    Wu, Sumei; He, Xingdao; Shen, Chenbo

    2008-03-01

    Multimode interference (MMI) couplers, based on the self-imaging effect (SIE), are accepted popularly in integrated optics. According to the importance of MMI devices, in this paper, we present a novel method to design and fabricate MMI couplers. A technology of maskless lithography to make MMI couplers based on a smart digital micro-mirror device (DMD) system is proposed. A 1×4 MMI device is designed as an example, which shows the present method is efficient and cost-effective.

  19. Directional couplers for detecting the TE sub 11 and TE sub 12 circular waveguide modes

    NASA Technical Reports Server (NTRS)

    Hoppe, D.

    1987-01-01

    The theoretical and experimental results for a pair of mode-selective directional couplers designed to detect the TE sub 11 and TE sub 12 modes in a multimode circular wavelength are described. A brief description of the design of the couplers is presented, followed by a comparison of their measured and calculated parameters. The couplers were used to measure the characteristics of a circular waveguide mode converter. The results of these measurements are described.

  20. High Performance, Three-Dimensional Bilateral Filtering

    SciTech Connect

    Bethel, E. Wes

    2008-06-05

    Image smoothing is a fundamental operation in computer vision and image processing. This work has two main thrusts: (1) implementation of a bilateral filter suitable for use in smoothing, or denoising, 3D volumetric data; (2) implementation of the 3D bilateral filter in three different parallelization models, along with parallel performance studies on two modern HPC architectures. Our bilateral filter formulation is based upon the work of Tomasi [11], but extended to 3D for use on volumetric data. Our three parallel implementations use POSIX threads, the Message Passing Interface (MPI), and Unified Parallel C (UPC), a Partitioned Global Address Space (PGAS) language. Our parallel performance studies, which were conducted on a Cray XT4 supercomputer and aquad-socket, quad-core Opteron workstation, show our algorithm to have near-perfect scalability up to 120 processors. Parallel algorithms, such as the one we present here, will have an increasingly important role for use in production visual analysis systems as the underlying computational platforms transition from single- to multi-core architectures in the future.

  1. Compact waveguide grating couplers operating in the strong coupling regime

    NASA Astrophysics Data System (ADS)

    Wang, Bin

    2005-07-01

    Since both photonic crystal and high index contrast waveguide photonic devices allow for tighter bend radii and thus reduced die size, they are being actively investigated for use in dense planar lightwave circuits (PLCs). To fully realize highly integrated PLCs, an efficient optical connection interface between single mode fibers or fiber arrays and high-index-contrast waveguides is required. The core size of single-mode fiber is typically 4--9mum while the core size of high-index-contrast waveguides is usually less than 1 to 2mum. Due to the mode size mismatch between the fiber and the waveguide, coupling light into small waveguides is challenging. This results in prohibitive insertion loss and extreme difficulty in fiber alignment for simple pigtail coupling, in which the end of a fiber is aligned and placed next to the end face of a waveguide. In addition, with input and output coupling taking place only along the edge of a chip at the plane of the waveguide device layer, this edge coupling arrangement severely limits the number of optical I/Os in dense PLCs. Moreover, fiber alignment has to be done after the wafer is diced into separate chips, and the end facet of the waveguide needs to be cut and polished. As a result, alignment and packaging accounts for the main manufacturing cost of optical components. In order to fully realize the potential of highly integrated PLCs, a new coupling approach needs to be developed, especially one that permits input and output to a 2-D array of fibers. The goal of this dissertation is to develop a high efficiency coupling method based on grating couplers operating in the strong coupling regime for fibers oriented normal to the waveguide plane without any intermediate optics between the fibers and waveguides. Development of this capability allows for relaxed fiber alignment requirements and wafer-scale alignment and testing. In this dissertation, three types of grating couplers that operate in the strong coupling regime are

  2. High Performance Computing and Communications Panel Report.

    ERIC Educational Resources Information Center

    President's Council of Advisors on Science and Technology, Washington, DC.

    This report offers advice on the strengths and weaknesses of the High Performance Computing and Communications (HPCC) initiative, one of five presidential initiatives launched in 1992 and coordinated by the Federal Coordinating Council for Science, Engineering, and Technology. The HPCC program has the following objectives: (1) to extend U.S.…

  3. High Performance Builder Spotlight: Imagine Homes

    SciTech Connect

    2011-01-01

    Imagine Homes, working with the DOE's Building America research team member IBACOS, has developed a system that can be replicated by other contractors to build affordable, high-performance homes. Imagine Homes has used the system to produce more than 70 Builders Challenge-certified homes per year in San Antonio over the past five years.

  4. Co-design for high performance computing.

    SciTech Connect

    Dosanjh, Sudip Singh; Hemmert, Karl Scott; Rodrigues, Arun F.

    2010-07-01

    Co-design has been identified as a key strategy for achieving Exascale computing in this decade. This paper describes the need for co-design in High Performance Computing related research in embedded computing the development of hardware/software co-simulation methods.

  5. High Poverty, High Performing Schools. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1997

    1997-01-01

    This theme issue includes four articles on high performance by poor Texas schools. In "Principal of National Blue Ribbon School Says High Poverty Schools Can Excel" (interview with Robert Zarate by Christie L. Goodman), the principal of Mary Hull Elementary School (San Antonio, Texas) describes how the high-poverty, high-minority school…

  6. Overview of high performance aircraft propulsion research

    NASA Technical Reports Server (NTRS)

    Biesiadny, Thomas J.

    1992-01-01

    The overall scope of the NASA Lewis High Performance Aircraft Propulsion Research Program is presented. High performance fighter aircraft of interest include supersonic flights with such capabilities as short take off and vertical landing (STOVL) and/or high maneuverability. The NASA Lewis effort involving STOVL propulsion systems is focused primarily on component-level experimental and analytical research. The high-maneuverability portion of this effort, called the High Alpha Technology Program (HATP), is part of a cooperative program among NASA's Lewis, Langley, Ames, and Dryden facilities. The overall objective of the NASA Inlet Experiments portion of the HATP, which NASA Lewis leads, is to develop and enhance inlet technology that will ensure high performance and stability of the propulsion system during aircraft maneuvers at high angles of attack. To accomplish this objective, both wind-tunnel and flight experiments are used to obtain steady-state and dynamic data, and computational fluid dynamics (CFD) codes are used for analyses. This overview of the High Performance Aircraft Propulsion Research Program includes a sampling of the results obtained thus far and plans for the future.

  7. High Performance Networks for High Impact Science

    SciTech Connect

    Scott, Mary A.; Bair, Raymond A.

    2003-02-13

    This workshop was the first major activity in developing a strategic plan for high-performance networking in the Office of Science. Held August 13 through 15, 2002, it brought together a selection of end users, especially representing the emerging, high-visibility initiatives, and network visionaries to identify opportunities and begin defining the path forward.

  8. Debugging a high performance computing program

    DOEpatents

    Gooding, Thomas M.

    2014-08-19

    Methods, apparatus, and computer program products are disclosed for debugging a high performance computing program by gathering lists of addresses of calling instructions for a plurality of threads of execution of the program, assigning the threads to groups in dependence upon the addresses, and displaying the groups to identify defective threads.

  9. Debugging a high performance computing program

    DOEpatents

    Gooding, Thomas M.

    2013-08-20

    Methods, apparatus, and computer program products are disclosed for debugging a high performance computing program by gathering lists of addresses of calling instructions for a plurality of threads of execution of the program, assigning the threads to groups in dependence upon the addresses, and displaying the groups to identify defective threads.

  10. High Performance Work Organizations. Myths and Realities.

    ERIC Educational Resources Information Center

    Kerka, Sandra

    Organizations are being urged to become "high performance work organizations" (HPWOs) and vocational teachers have begun considering how best to prepare workers for them. Little consensus exists as to what HPWOs are. Several common characteristics of HPWOs have been identified, and two distinct models of HPWOs are emerging in the United States.…

  11. Performance, Performance System, and High Performance System

    ERIC Educational Resources Information Center

    Jang, Hwan Young

    2009-01-01

    This article proposes needed transitions in the field of human performance technology. The following three transitions are discussed: transitioning from training to performance, transitioning from performance to performance system, and transitioning from learning organization to high performance system. A proposed framework that comprises…

  12. Project materials [Commercial High Performance Buildings Project

    SciTech Connect

    2001-01-01

    The Consortium for High Performance Buildings (ChiPB) is an outgrowth of DOE'S Commercial Whole Buildings Roadmapping initiatives. It is a team-driven public/private partnership that seeks to enable and demonstrate the benefit of buildings that are designed, built and operated to be energy efficient, environmentally sustainable, superior quality, and cost effective.

  13. Using LEADS to shift to high performance.

    PubMed

    Fenwick, Shauna; Hagge, Erna

    2016-03-01

    Health systems across Canada are tasked to measure results of all their strategic initiatives. Included in most strategic plans is leadership development. How to measure leadership effectiveness in relation to organizational objectives is key in determining organizational effectiveness. The following findings offer considerations for a 21(st)-century approach to shifting to high-performance systems. PMID:26872796

  14. Commercial Buildings High Performance Rooftop Unit Challenge

    SciTech Connect

    2011-12-16

    The U.S. Department of Energy (DOE) and the Commercial Building Energy Alliances (CBEAs) are releasing a new design specification for high performance rooftop air conditioning units (RTUs). Manufacturers who develop RTUs based on this new specification will find strong interest from the commercial sector due to the energy and financial savings.

  15. High Performance Work Systems for Online Education

    ERIC Educational Resources Information Center

    Contacos-Sawyer, Jonna; Revels, Mark; Ciampa, Mark

    2010-01-01

    The purpose of this paper is to identify the key elements of a High Performance Work System (HPWS) and explore the possibility of implementation in an online institution of higher learning. With the projected rapid growth of the demand for online education and its importance in post-secondary education, providing high quality curriculum, excellent…

  16. Quantitative comparison of dynamic flux distribution of magnetic couplers for roadway electric vehicle wireless charging system

    NASA Astrophysics Data System (ADS)

    Qiu, Chun; Chau, K. T.; Liu, Chunhua; Li, Wenlong; Lin, Fei

    2014-05-01

    This paper gives a quantitative comparison of magnetic couplers for electric vehicle (EV) wireless charging applications. Circular pad with ferrite spokes and coreless rectangular coils are specially selected for analysis. The dynamic flux density between couplers under high misalignment is studied by calculating the uncompensated power of the pick-up coupler. By using finite element analysis, the performance of each type of coupler is evaluated, and its adaptation to on-road EV charging are compared according to the flux distribution and effective charging area.

  17. Proceedings of the fifth IEEE international symposium on high performance distributed computing

    SciTech Connect

    1996-12-31

    This report contains papers from the Fifth IEEE International Symposium on High Performance Distributed Computing. Some of the areas covered are: collaboration tools (multimedia track); applications; distributed and parallel programming; metacomputing track; multimedia applications; tools and practice; networks for distributed applications; multimedia networks; languages and algorithms; networks of workstations; metacomputing track - invited papers; quality of service; distributed shared memory; networks and protocols; I/O systems and storage; wide-area distributed systems; communications - design and architecture; and parallel systems.

  18. The high performance storage system (HPSS)

    SciTech Connect

    Kliewer, K.L.

    1995-12-31

    Ever more powerful computers and rapidly enlarging data sets require unprecedented levels of data storage and access capabilities. To help meet these requirements, the scalable, network-centered, parallel storage system HPSS was designed and is now being developed. The parallel 1/0 architecture, mechanisms, strategies and capabilities are described. The current development status and the broad applicability are illustrated through a discussion of the sites at which HPSS is now being implemented, representing a spectrum of computing environments. Planned capabilities and time scales will be provided. Some of the remarkable developments in storage media data density looming on the horizon will also be noted.

  19. Monitoring SLAC High Performance UNIX Computing Systems

    SciTech Connect

    Lettsome, Annette K.; /Bethune-Cookman Coll. /SLAC

    2005-12-15

    Knowledge of the effectiveness and efficiency of computers is important when working with high performance systems. The monitoring of such systems is advantageous in order to foresee possible misfortunes or system failures. Ganglia is a software system designed for high performance computing systems to retrieve specific monitoring information. An alternative storage facility for Ganglia's collected data is needed since its default storage system, the round-robin database (RRD), struggles with data integrity. The creation of a script-driven MySQL database solves this dilemma. This paper describes the process took in the creation and implementation of the MySQL database for use by Ganglia. Comparisons between data storage by both databases are made using gnuplot and Ganglia's real-time graphical user interface.

  20. High performance microsystem packaging: A perspective

    SciTech Connect

    Romig, A.D. Jr.; Dressendorfer, P.V.; Palmer, D.W.

    1997-10-01

    The second silicon revolution will be based on intelligent, integrated microsystems where multiple technologies (such as analog, digital, memory, sensor, micro-electro-mechanical, and communication devices) are integrated onto a single chip or within a multichip module. A necessary element for such systems is cost-effective, high-performance packaging. This paper examines many of the issues associated with the packaging of integrated microsystems, with an emphasis on the areas of packaging design, manufacturability, and reliability.

  1. ADVANCED HIGH PERFORMANCE SOLID WALL BLANKET CONCEPTS

    SciTech Connect

    WONG, CPC; MALANG, S; NISHIO, S; RAFFRAY, R; SAGARA, S

    2002-04-01

    OAK A271 ADVANCED HIGH PERFORMANCE SOLID WALL BLANKET CONCEPTS. First wall and blanket (FW/blanket) design is a crucial element in the performance and acceptance of a fusion power plant. High temperature structural and breeding materials are needed for high thermal performance. A suitable combination of structural design with the selected materials is necessary for D-T fuel sufficiency. Whenever possible, low afterheat, low chemical reactivity and low activation materials are desired to achieve passive safety and minimize the amount of high-level waste. Of course the selected fusion FW/blanket design will have to match the operational scenarios of high performance plasma. The key characteristics of eight advanced high performance FW/blanket concepts are presented in this paper. Design configurations, performance characteristics, unique advantages and issues are summarized. All reviewed designs can satisfy most of the necessary design goals. For further development, in concert with the advancement in plasma control and scrape off layer physics, additional emphasis will be needed in the areas of first wall coating material selection, design of plasma stabilization coils, consideration of reactor startup and transient events. To validate the projected performance of the advanced FW/blanket concepts the critical element is the need for 14 MeV neutron irradiation facilities for the generation of necessary engineering design data and the prediction of FW/blanket components lifetime and availability.

  2. Programming high-performance reconfigurable computers

    NASA Astrophysics Data System (ADS)

    Smith, Melissa C.; Peterson, Gregory D.

    2001-07-01

    High Performance Computers (HPC) provide dramatically improved capabilities for a number of defense and commercial applications, but often are too expensive to acquire and to program. The smaller market and customized nature of HPC architectures combine to increase the cost of most such platforms. To address the problems with high hardware costs, one may create more inexpensive Beowolf clusters of dedicated commodity processors. Despite the benefit of reduced hardware costs, programming the HPC platforms to achieve high performance often proves extremely time-consuming and expensive in practice. In recent years, programming productivity gains come from the development of common APIs and libraries of functions to support distributed applications. Examples include PVM, MPI, BLAS, and VSIPL. The implementation of each API or library is optimized for a given platform, but application developers can write code that is portable across specific HPC architectures. The application of reconfigurable computing (RC) into HPC platforms promises significantly enhanced performance and flexibility at a modest cost. Unfortunately, configuring (programming) the reconfigurable computing nodes remains a challenging task and relatively little work to date has focused on potential high performance reconfigurable computing (HPRC) platforms consisting of reconfigurable nodes paired with processing nodes. This paper addresses the challenge of effectively exploiting HPRC resources by first considering the performance evaluation and optimization problem before turning to improving the programming infrastructure used for porting applications to HPRC platforms.

  3. Computational Biology and High Performance Computing 2000

    SciTech Connect

    Simon, Horst D.; Zorn, Manfred D.; Spengler, Sylvia J.; Shoichet, Brian K.; Stewart, Craig; Dubchak, Inna L.; Arkin, Adam P.

    2000-10-19

    The pace of extraordinary advances in molecular biology has accelerated in the past decade due in large part to discoveries coming from genome projects on human and model organisms. The advances in the genome project so far, happening well ahead of schedule and under budget, have exceeded any dreams by its protagonists, let alone formal expectations. Biologists expect the next phase of the genome project to be even more startling in terms of dramatic breakthroughs in our understanding of human biology, the biology of health and of disease. Only today can biologists begin to envision the necessary experimental, computational and theoretical steps necessary to exploit genome sequence information for its medical impact, its contribution to biotechnology and economic competitiveness, and its ultimate contribution to environmental quality. High performance computing has become one of the critical enabling technologies, which will help to translate this vision of future advances in biology into reality. Biologists are increasingly becoming aware of the potential of high performance computing. The goal of this tutorial is to introduce the exciting new developments in computational biology and genomics to the high performance computing community.

  4. Achieving High Performance Perovskite Solar Cells

    NASA Astrophysics Data System (ADS)

    Yang, Yang

    2015-03-01

    Recently, metal halide perovskite based solar cell with the characteristics of rather low raw materials cost, great potential for simple process and scalable production, and extreme high power conversion efficiency (PCE), have been highlighted as one of the most competitive technologies for next generation thin film photovoltaic (PV). In UCLA, we have realized an efficient pathway to achieve high performance pervoskite solar cells, where the findings are beneficial to this unique materials/devices system. Our recent progress lies in perovskite film formation, defect passivation, transport materials design, interface engineering with respect to high performance solar cell, as well as the exploration of its applications beyond photovoltaics. These achievements include: 1) development of vapor assisted solution process (VASP) and moisture assisted solution process, which produces perovskite film with improved conformity, high crystallinity, reduced recombination rate, and the resulting high performance; 2) examination of the defects property of perovskite materials, and demonstration of a self-induced passivation approach to reduce carrier recombination; 3) interface engineering based on design of the carrier transport materials and the electrodes, in combination with high quality perovskite film, which delivers 15 ~ 20% PCEs; 4) a novel integration of bulk heterojunction to perovskite solar cell to achieve better light harvest; 5) fabrication of inverted solar cell device with high efficiency and flexibility and 6) exploration the application of perovskite materials to photodetector. Further development in film, device architecture, and interfaces will lead to continuous improved perovskite solar cells and other organic-inorganic hybrid optoelectronics.

  5. Current-drive on the Versator-2 tokamak with a slotted-waveguide fast-wave coupler

    NASA Astrophysics Data System (ADS)

    Colborn, J. A.

    1987-11-01

    A slotted-waveguide fast-wave coupler has been constructed, without dielectric, and used to drive current on the Versator-2 tokamak. Up to 35 kW of net microwave power at 2.45 GHz has been radiated into plasmas with 2 x 10 to the 12th/cu cm less than or equal to mean of n(sub e) less than or equal to 1.2 x 10 to the 13th/cu cm and B(sub tor) approx. = 1.0 T. The launched spectrum had a peak near N(sub parallel) = -2.0 and a larger peak near N(sub parallel) = 0.7. Radiating efficiency of the antenna was roughly independent of antenna position except when the antenna was at least 0.2 cm outside the limiter, in which case the radiating efficiency slightly improved as the antenna was moved farther outside. When the coupler was inside the limiter, radiating efficiency improved moderately with increased mean of n(sub e). Current-drive efficiency was comparable to that of the slow wave and was not affected when the antenna spectrum was reversed; however, no current was driven for mean of n(sub e) less than or equal to 2 x 10 to the 12th/cu cm. These results indicate the fast wave was launched, but a substantial part of the power may have been mode-converted to the slow wave, possible via a downshift in N(sub parallel), and these slow waves may have been responsible for most of the driven current. Relevant theory for waves in plasma, current-drive efficiency, and coupling of the slotted-waveguide is discussed, the antenna design method is explained, and future work, including the construction of a much-improved probe-fed antenna, is described.

  6. Green Schools as High Performance Learning Facilities

    ERIC Educational Resources Information Center

    Gordon, Douglas E.

    2010-01-01

    In practice, a green school is the physical result of a consensus process of planning, design, and construction that takes into account a building's performance over its entire 50- to 60-year life cycle. The main focus of the process is to reinforce optimal learning, a goal very much in keeping with the parallel goals of resource efficiency and…

  7. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, T.W. Jr.; Johnson, G.W.; O`Brien, D.W.

    1995-05-09

    A high performance capacitor is fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a ``notepad`` configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The notepad capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density. 5 figs.

  8. A high performance scientific cloud computing environment for materials simulations

    NASA Astrophysics Data System (ADS)

    Jorissen, K.; Vila, F. D.; Rehr, J. J.

    2012-09-01

    We describe the development of a scientific cloud computing (SCC) platform that offers high performance computation capability. The platform consists of a scientific virtual machine prototype containing a UNIX operating system and several materials science codes, together with essential interface tools (an SCC toolset) that offers functionality comparable to local compute clusters. In particular, our SCC toolset provides automatic creation of virtual clusters for parallel computing, including tools for execution and monitoring performance, as well as efficient I/O utilities that enable seamless connections to and from the cloud. Our SCC platform is optimized for the Amazon Elastic Compute Cloud (EC2). We present benchmarks for prototypical scientific applications and demonstrate performance comparable to local compute clusters. To facilitate code execution and provide user-friendly access, we have also integrated cloud computing capability in a JAVA-based GUI. Our SCC platform may be an alternative to traditional HPC resources for materials science or quantum chemistry applications.

  9. Java-based communication in a High Performance Computing environment

    NASA Astrophysics Data System (ADS)

    Fries, A.; de Mora, J. Portell I.; Sirvent, R.

    2011-02-01

    Java is one of the most widely used computer programming languages, however its use in High Performance Computing (HPC) is relatively low. A typical HPC environment consists of a number of multi-core computing nodes, while a typical application running in such an environment will normally contain CPU intensive code that can be executed in parallel. Such an application may require inter-node as well as intra-node communication. Message Passing Interface (MPI) is a language independent specification of an API to allow such communication. MPJExpress (Baker et al. 2006) and F-MPJ (Taboada et al. 2009) are Java-based implementations of MPI, designed with the efficient performance of data transfers as a main objective. In this paper we discuss the scalability of one approach of distributing data to compute nodes in HPC and we propose the design of an alternative data transfer system, building upon MPI.

  10. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, T.W. Jr.; Johnson, G.W.; O`Brien, D.W.

    1996-01-23

    A high performance capacitor is described which is fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a ``notepad`` configuration composed of 200--300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The ``notepad`` capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density. 5 figs.

  11. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, Jr., Troy W.; Johnson, Gary W.; O'Brien, Dennis W.

    1995-01-01

    A high performance capacitor fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a "notepad" configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The "notepad" capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density.

  12. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, Jr., Troy W.; Johnson, Gary W.; O'Brien, Dennis W.

    1996-01-01

    A high performance capacitor fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a "notepad" configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The "notepad" capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density.

  13. High Performance Multivariate Visual Data Exploration for Extremely Large Data

    SciTech Connect

    Rubel, Oliver; Wu, Kesheng; Childs, Hank; Meredith, Jeremy; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Ahern, Sean; Weber, Gunther H.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes; Prabhat,

    2008-08-22

    One of the central challenges in modern science is the need to quickly derive knowledge and understanding from large, complex collections of data. We present a new approach that deals with this challenge by combining and extending techniques from high performance visual data analysis and scientific data management. This approach is demonstrated within the context of gaining insight from complex, time-varying datasets produced by a laser wakefield accelerator simulation. Our approach leverages histogram-based parallel coordinates for both visual information display as well as a vehicle for guiding a data mining operation. Data extraction and subsetting are implemented with state-of-the-art index/query technology. This approach, while applied here to accelerator science, is generally applicable to a broad set of science applications, and is implemented in a production-quality visual data analysis infrastructure. We conduct a detailed performance analysis and demonstrate good scalability on a distributed memory Cray XT4 system.

  14. Middleware in Modern High Performance Computing System Architectures

    SciTech Connect

    Engelmann, Christian; Ong, Hong Hoe; Scott, Stephen L

    2007-01-01

    A recent trend in modern high performance computing (HPC) system architectures employs ''lean'' compute nodes running a lightweight operating system (OS). Certain parts of the OS as well as other system software services are moved to service nodes in order to increase performance and scalability. This paper examines the impact of this HPC system architecture trend on HPC ''middleware'' software solutions, which traditionally equip HPC systems with advanced features, such as parallel and distributed programming models, appropriate system resource management mechanisms, remote application steering and user interaction techniques. Since the approach of keeping the compute node software stack small and simple is orthogonal to the middleware concept of adding missing OS features between OS and application, the role and architecture of middleware in modern HPC systems needs to be revisited. The result is a paradigm shift in HPC middleware design, where single middleware services are moved to service nodes, while runtime environments (RTEs) continue to reside on compute nodes.

  15. On-chip optical mode exchange using tapered directional coupler

    PubMed Central

    Zhang, Zhonglai; Hu, Xiao; Wang, Jian

    2015-01-01

    We present an on-chip optical mode exchange between two multiplexed modes by using tapered directional couplers on silicon-on-insulator platform. The device consisting of mode multiplexing and mode exchange is compact with relatively large fabrication error tolerance. The simulation results show efficient higher order mode excitation and mode exchange. A low excess loss less than 0.5 dB and high extinction ratio larger than 15 dB over 10 nm wavelength range from 1535 to 1545 nm are achieved. PMID:26530728

  16. Joint photon and wave statistics in nonlinear optical couplers

    NASA Astrophysics Data System (ADS)

    Peřina, Jan; Křepelka, Jaromír

    2014-09-01

    Nonlinear optical couplers based on optical parametric processes and Raman-Brillouin scattering are discussed from the point of view of their nonclassical behaviour using joint photon-number and integrated-intensity probability distributions and derived quantum statistical quantities. Employing these tools quantum entanglement of modes and their nonclassical properties are demonstrated by means of conditional probability distributions and their Fano factors, difference-number probability distributions, quantum oscillations, squeezing of vacuum fluctuations and negative values of the joint wave probability quasidistributions in time evolution. Sub-Poissonian and sub-shot-noise properties are determined for initial coherent, chaotic and squeezed light.

  17. Optical fiber null coupler sensor for damage detection using ultrasonic

    NASA Astrophysics Data System (ADS)

    Xuan, HaiFeng; Liao, Yanbiao; Zhang, Ming; Lai, Shu R.

    2005-02-01

    A novel optical fiber null coupler (OFNC) sensor based on acousto-optic interaction is developed, which can be used in the structure health monitoring of the medical materials. The OFNC sensors can be response to 10MHz supersonic wave, and their signal-to noise ratio are higher then Piezo Ceramic Transducers(PZT). A kind of Perspex with a 1mm hole is employed as the sample, where the OFNC sensor is glued on, and the reflected signal of ultrasonic wave by the hole is detected .

  18. 30 CFR 77.805 - Cable couplers and connection boxes; minimum design requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Cable couplers and connection boxes; minimum..., DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.805 Cable couplers...

  19. 30 CFR 77.805 - Cable couplers and connection boxes; minimum design requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Cable couplers and connection boxes; minimum..., DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.805 Cable couplers...

  20. 30 CFR 77.805 - Cable couplers and connection boxes; minimum design requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Cable couplers and connection boxes; minimum..., DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.805 Cable couplers...

  1. 30 CFR 77.805 - Cable couplers and connection boxes; minimum design requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Cable couplers and connection boxes; minimum..., DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.805 Cable couplers...

  2. Design and performance of the asymmetrical coupler of plastic optical fibers

    NASA Astrophysics Data System (ADS)

    Kruszewski, Jerzy; Borecki, Michal; Beblowska, Maria

    2004-09-01

    Presented work concerns designing and making the asymmetric couplers. Three-dimensional fiber space modeling of light propagation have been used in the project. Couplers were made using two different technologies of gluing. Design results are confirmed by experiments and elements have expected parameters.

  3. Long-term performance of epoxy-bonded rebar-couplers

    NASA Astrophysics Data System (ADS)

    Brungraber, Griffin Rupp

    Rebar-couplers mechanically splice pairs of steel reinforcing bars, end-to-end; they are used regularly in reinforced concrete construction. Epoxy-bonded couplers are one available type, but have unique long-term performance considerations. The adhesive material used in these couplers is a two-part, field-mixed, ambient-cure epoxy system, originally designed for adhesive anchorage to concrete. Many of the adhesive systems used for anchorage to concrete, including the system used with adhesive-bonded couplers, are epoxy systems. The mechanical properties of these types of epoxies have been shown to degrade over time, in the presence of moisture. A variety of commercially available adhesive systems, for anchorage to concrete, were studied to assess their relative resistance to moisture-based degradation. The material properties of two of the adhesive systems, both epoxies, and the performance of the rebar-couplers were then measured over a fourteen-and-a-half-month period of exposure to a variety of environmental conditions, including water immersion at a range of temperatures. From these results, material degradation models were used to predict the properties of the adhesive over the service life of the rebar-coupler. A Finite Element Analysis (FEA) model was developed to simulate the tensile failure of the epoxy-bonded rebar-coupler system and correlate degrading adhesive material properties to changes in the coupler system's behavior throughout its service life.

  4. Effects of beam focusing on the efficiency of planar waveguide grating couplers

    NASA Technical Reports Server (NTRS)

    Li, Lifeng; Gupta, Mool C.

    1991-01-01

    Results of a theoretical and experimental study into the variation of coupling efficiency with a grating angle are presented for various beam focusing conditions for an integrated optical grating coupler. The study shows that the acceptance angle of the grating coupler can be broadened within a relatively large range and with a relatively small loss of coupling efficiency, by focusing the incident laser beam.

  5. High performance computing: Clusters, constellations, MPPs, and future directions

    SciTech Connect

    Dongarra, Jack; Sterling, Thomas; Simon, Horst; Strohmaier, Erich

    2003-06-10

    Last year's paper by Bell and Gray [1] examined past trends in high performance computing and asserted likely future directions based on market forces. While many of the insights drawn from this perspective have merit and suggest elements governing likely future directions for HPC, there are a number of points put forth that we feel require further discussion and, in certain cases, suggest alternative, more likely views. One area of concern relates to the nature and use of key terms to describe and distinguish among classes of high end computing systems, in particular the authors use of ''cluster'' to relate to essentially all parallel computers derived through the integration of replicated components. The taxonomy implicit in their previous paper, while arguable and supported by some elements of our community, fails to provide the essential semantic discrimination critical to the effectiveness of descriptive terms as tools in managing the conceptual space of consideration. In this paper, we present a perspective that retains the descriptive richness while providing a unifying framework. A second area of discourse that calls for additional commentary is the likely future path of system evolution that will lead to effective and affordable Petaflops-scale computing including the future role of computer centers as facilities for supporting high performance computing environments. This paper addresses the key issues of taxonomy, future directions towards Petaflops computing, and the important role of computer centers in the 21st century.

  6. USING MULTIRAIL NETWORKS IN HIGH-PERFORMANCE CLUSTERS

    SciTech Connect

    Coll, S.; Fratchtenberg, E.; Petrini, F.; Hoisie, A.; Gurvits, L.

    2001-01-01

    Using multiple independent networks (also known as rails) is an emerging technique to overcome bandwidth limitations and enhance fault tolerance of current high-performance clusters. We present an extensive experimental comparison of the behavior of various allocation schemes in terms of bandwidth and latency. We show that striping messages over multiple rails can substantially reduce network latency, depending on average message size, network load, and allocation scheme. The compared methods include a basic round-robin rail allocation, a local-dynamic allocation based on local knowledge, and a dynamic rail allocation that reserves both communication endpoints of a message before sending it. The last method is shown to perform better than the others at higher loads: up to 49% better than local-knowledge allocation and 37% better than the round-robin allocation. This allocation scheme also shows lower latency and it saturates on higher loads (for messages large enough). Most importantly, this proposed allocation scheme scales well with the number of rails and message sizes. In addition we propose a hybrid algorithm that combines the benefits of the local-dynamic for short messages with those of the dynamic algorithm for large messages. Keywords: Communication Protocols, High-Performance Interconnection Networks, Performance Evaluation, Routing, Communication Libraries, Parallel Architectures.

  7. DIAGNOSIS, ANALYSIS, AND RESOLUTION OF THERMAL STABILITY ISSUES WITH HOM COUPLERS ON PROTOTYPE CEBAF SRF CAVITIES

    SciTech Connect

    Charles Reece; Edward Daly; G. Davis; William Hicks; Timothy Rothgeb; H. Phillips; Joseph Preble; Haipeng Wang; Genfa Wu

    2008-02-12

    During initial testing of the prototype cavities incorporated into the developmental cryomodule Renascence severe thermal stability issues were encountered during CW operation. Additional diagnostic instrumentation was added. This enabled identification of an unanticipated thermal impedance between the HOM coupler probe feedthrough assembly and the cavity beamtube. Subsequent detailed FE analysis successfully modeled the situation and indicated the need for alternate cooling path for the couplers on those cavities. HOM damping was measured to be adequate employing only two of the four HOM couplers. The two pickup probes on the couplers at the input power coupler side of each cavity were removed, the remaining HOM probe feedthroughs were heat stationed to two-phase helium supply piping, and a novel heat sink was added to station both the inner and outer conductors of the remaining HOM rf cables. The characterization measurements, analysis, modifications, and resulting performance are presented.

  8. Precision measurement system and analysis of low core signal loss in DCF couplers

    NASA Astrophysics Data System (ADS)

    Yan, P.; Wang, X. J.; Fu, Ch; Li, D.; Sun, J. Y.; Gong, M. L.; Xiao, Q. R.

    2016-07-01

    In order to achieve higher output power of double cladding fiber lasers, low signal loss has become a focus in researches on optical technology, especially double-clad fiber (DCF) couplers. According to the analysis, DCF couplers with low core signal loss (less than 1%) are produced. To obtain higher precision, we use the first-proposed method for core signal transfer efficiency measurement based on the fiber propagation field image processing. To the best of our knowledge, we report, for the first time, the results of the core signal loss less than 1% in DCF coupler measured by our measurement with high stability and relative precision. The measurement values can assess the quality of DCF couplers and be used as a signal to suggest the improvement on the processing technology of our self-made DCF couplers.

  9. Measurements of ICRF (ion cyclotron range of frequencies) loading with a ridged waveguide coupler on PLT

    SciTech Connect

    Greene, G.J.; Wilson, J.R.; Colestock, P.L.; Fortgang, C.M.; Hosea, J.C.; Hwang, D.Q.; Nagy, A.

    1987-11-01

    An ICRF ridged waveguide coupler has been installed on PLT for measurements of plasma loading. The coupler was partially filled with TiO/sub 2/ dielectric in order to sufficiently lower the cutoff frequency and utilized a tapered ridge for improved matching. Vacuum field measurements indicated a single propagating mode in the coupler and emphasized the importance of considering the fringing fields at the mouth of the waveguide. Low power experiments were carried out at 72.6 and 95.0 MHz without any external impedance matching network. Plasma loading increased rapidly as the face of the coupler approached the plasma, and, at fixed position, increased with line-averaged plasma density. At the lower frequency, the reflection coefficient exhibited a minimum (<8%) at a particular coupler position. At both frequencies, measurements indicated efficient power coupling to the plasma. Magnetic probe signals showed evidence of dense eigenmodes suggesting excitation of the fast wave. 24 refs., 13 figs.

  10. Broadly tunable multiwavelength Brillouin-erbium fiber laser using a twin-core fiber coupler

    NASA Astrophysics Data System (ADS)

    Peng, Wanjing; Yan, Fengping; Li, Qi; Liu, Shuo; Tan, Siyu; Feng, Suchun; Feng, Ting

    2014-07-01

    A tunable multiwavelength Brillouin-erbium fiber laser (MW-BEFL) using a twin-core fiber (TCF) coupler is proposed and demonstrated. The TCF coupler is formed by splicing a section of TCF between two single-mode fibers. By simply applying bending curvature on the TCF coupler, the peak net gain is shifted close to the Brillouin pump (BP), which has advantage for suppressing self-lasing cavity modes with low-BP-power injection. In this work, the dependency of the Stokes signals tuning range on the free spectral range (FSR) of TCF coupler is studied. It is also found that the tuning range of MW-BEFL can exceed the FSR of TCF coupler by adopting proper BP power and 980-nm pump power. Up to 40 nm tuning range of MW-BEFL in the absence of self-lasing cavity modes is achieved.

  11. Problem Knowledge Couplers: reengineering evidence-based medicine through interdisciplinary development, decision support, and research.

    PubMed Central

    McGowan, J J; Winstead-Fry, P

    1999-01-01

    The rapid growth of medical knowledge is creating a demand for new ways of providing information in support of evidence-based medical practice. Problem Knowledge Couplers are a clinical decision support software tool that offer a new approach to this growing problem. Couplers are developed through a collaboration among clinicians, informaticians, and librarians. They recognize that functionality must be predicated upon combining unique patient information, gleaned through relevant structured question sets, with the appropriate knowledge found in the world's peer-reviewed medical literature. Two pilot studies indicate that couplers can meet the gold standards of decision making within both a primary care and a specialty practice. Issues remain about how to best integrate Problem Knowledge Couplers into clinical practice and whether large-scale outcomes research will support the findings of pilot studies. However, Problem Knowledge Couplers represent a promising approach that might portend a new model for health care delivery in the next millennium. PMID:10550032

  12. Problem Knowledge Couplers: reengineering evidence-based medicine through interdisciplinary development, decision support, and research.

    PubMed

    McGowan, J J; Winstead-Fry, P

    1999-10-01

    The rapid growth of medical knowledge is creating a demand for new ways of providing information in support of evidence-based medical practice. Problem Knowledge Couplers are a clinical decision support software tool that offer a new approach to this growing problem. Couplers are developed through a collaboration among clinicians, informaticians, and librarians. They recognize that functionality must be predicated upon combining unique patient information, gleaned through relevant structured question sets, with the appropriate knowledge found in the world's peer-reviewed medical literature. Two pilot studies indicate that couplers can meet the gold standards of decision making within both a primary care and a specialty practice. Issues remain about how to best integrate Problem Knowledge Couplers into clinical practice and whether large-scale outcomes research will support the findings of pilot studies. However, Problem Knowledge Couplers represent a promising approach that might portend a new model for health care delivery in the next millennium. PMID:10550032

  13. Failure analysis of high performance ballistic fibers

    NASA Astrophysics Data System (ADS)

    Spatola, Jennifer S.

    High performance fibers have a high tensile strength and modulus, good wear resistance, and a low density, making them ideal for applications in ballistic impact resistance, such as body armor. However, the observed ballistic performance of these fibers is much lower than the predicted values. Since the predictions assume only tensile stress failure, it is safe to assume that the stress state is affecting fiber performance. The purpose of this research was to determine if there are failure mode changes in the fiber fracture when transversely loaded by indenters of different shapes. An experimental design mimicking transverse impact was used to determine any such effects. Three different indenters were used: round, FSP, and razor blade. The indenter height was changed to change the angle of failure tested. Five high performance fibers were examined: KevlarRTM KM2, SpectraRTM 130d, DyneemaRTM SK-62 and SK-76, and ZylonRTM 555. Failed fibers were analyzed using an SEM to determine failure mechanisms. The results show that the round and razor blade indenters produced a constant failure strain, as well as failure mechanisms independent of testing angle. The FSP indenter produced a decrease in failure strain as the angle increased. Fibrillation was the dominant failure mechanism at all angles for the round indenter, while through thickness shearing was the failure mechanism for the razor blade. The FSP indenter showed a transition from fibrillation at low angles to through thickness shearing at high angles, indicating that the round and razor blade indenters are extreme cases of the FSP indenter. The failure mechanisms observed with the FSP indenter at various angles correlated with the experimental strain data obtained during fiber testing. This indicates that geometry of the indenter tip in compression is a contributing factor in lowering the failure strain of the high performance fibers. TEM analysis of the fiber failure mechanisms was also attempted, though without

  14. Toward a theory of high performance.

    PubMed

    Kirby, Julia

    2005-01-01

    What does it mean to be a high-performance company? The process of measuring relative performance across industries and eras, declaring top performers, and finding the common drivers of their success is such a difficult one that it might seem a fool's errand to attempt. In fact, no one did for the first thousand or so years of business history. The question didn't even occur to many scholars until Tom Peters and Bob Waterman released In Search of Excellence in 1982. Twenty-three years later, we've witnessed several more attempts--and, just maybe, we're getting closer to answers. In this reported piece, HBR senior editor Julia Kirby explores why it's so difficult to study high performance and how various research efforts--including those from John Kotter and Jim Heskett; Jim Collins and Jerry Porras; Bill Joyce, Nitin Nohria, and Bruce Roberson; and several others outlined in a summary chart-have attacked the problem. The challenge starts with deciding which companies to study closely. Are the stars the ones with the highest market caps, the ones with the greatest sales growth, or simply the ones that remain standing at the end of the game? (And when's the end of the game?) Each major study differs in how it defines success, which companies it therefore declares to be worthy of emulation, and the patterns of activity and attitude it finds in common among them. Yet, Kirby concludes, as each study's method incrementally solves problems others have faced, we are progressing toward a consensus theory of high performance. PMID:16028814

  15. Strategy Guideline. High Performance Residential Lighting

    SciTech Connect

    Holton, J.

    2012-02-01

    This report has been developed to provide a tool for the understanding and application of high performance lighting in the home. The strategies featured in this guide are drawn from recent advances in commercial lighting for application to typical spaces found in residential buildings. This guide offers strategies to greatly reduce lighting energy use through the application of high quality fluorescent and light emitting diode (LED) technologies. It is important to note that these strategies not only save energy in the home but also serve to satisfy the homeowner’s expectations for high quality lighting.

  16. High performance forward swept wing aircraft

    NASA Technical Reports Server (NTRS)

    Koenig, David G. (Inventor); Aoyagi, Kiyoshi (Inventor); Dudley, Michael R. (Inventor); Schmidt, Susan B. (Inventor)

    1988-01-01

    A high performance aircraft capable of subsonic, transonic and supersonic speeds employs a forward swept wing planform and at least one first and second solution ejector located on the inboard section of the wing. A high degree of flow control on the inboard sections of the wing is achieved along with improved maneuverability and control of pitch, roll and yaw. Lift loss is delayed to higher angles of attack than in conventional aircraft. In one embodiment the ejectors may be advantageously positioned spanwise on the wing while the ductwork is kept to a minimum.

  17. High-Performance Water-Iodinating Cartridge

    NASA Technical Reports Server (NTRS)

    Sauer, Richard; Gibbons, Randall E.; Flanagan, David T.

    1993-01-01

    High-performance cartridge contains bed of crystalline iodine iodinates water to near saturation in single pass. Cartridge includes stainless-steel housing equipped with inlet and outlet for water. Bed of iodine crystals divided into layers by polytetrafluoroethylene baffles. Holes made in baffles and positioned to maximize length of flow path through layers of iodine crystals. Resulting concentration of iodine biocidal; suppresses growth of microbes in stored water or disinfects contaminated equipment. Cartridge resists corrosion and can be stored wet. Reused several times before necessary to refill with fresh iodine crystals.

  18. High-performance neural networks. [Neural computers

    SciTech Connect

    Dress, W.B.

    1987-06-01

    The new Forth hardware architectures offer an intermediate solution to high-performance neural networks while the theory and programming details of neural networks for synthetic intelligence are developed. This approach has been used successfully to determine the parameters and run the resulting network for a synthetic insect consisting of a 200-node ''brain'' with 1760 interconnections. Both the insect's environment and its sensor input have thus far been simulated. However, the frequency-coded nature of the Browning network allows easy replacement of the simulated sensors by real-world counterparts.

  19. An Introduction to High Performance Computing

    NASA Astrophysics Data System (ADS)

    Almeida, Sérgio

    2013-09-01

    High Performance Computing (HPC) has become an essential tool in every researcher's arsenal. Most research problems nowadays can be simulated, clarified or experimentally tested by using computational simulations. Researchers struggle with computational problems when they should be focusing on their research problems. Since most researchers have little-to-no knowledge in low-level computer science, they tend to look at computer programs as extensions of their minds and bodies instead of completely autonomous systems. Since computers do not work the same way as humans, the result is usually Low Performance Computing where HPC would be expected.

  20. High performance pitch-based carbon fiber

    SciTech Connect

    Tadokoro, Hiroyuki; Tsuji, Nobuyuki; Shibata, Hirotaka; Furuyama, Masatoshi

    1996-12-31

    The high performance pitch-based carbon fiber with smaller diameter, six micro in developed by Nippon Graphite Fiber Corporation. This fiber possesses high tensile modulus, high tensile strength, excellent yarn handle ability, low thermal expansion coefficient, and high thermal conductivity which make it an ideal material for space applications such as artificial satellites. Performance of this fiber as a reinforcement of composites was sufficient. With these characteristics, this pitch-based carbon fiber is expected to find wide variety of possible applications in space structures, industrial field, sporting goods and civil infrastructures.

  1. Portability Support for High Performance Computing

    NASA Technical Reports Server (NTRS)

    Cheng, Doreen Y.; Cooper, D. M. (Technical Monitor)

    1994-01-01

    While a large number of tools have been developed to support application portability, high performance application developers often prefer to use vendor-provided, non-portable programming interfaces. This phenomena indicates the mismatch between user priorities and tool capabilities. This paper summarizes the results of a user survey and a developer survey. The user survey has revealed the user priorities and resulted in three criteria for evaluating tool support for portability. The developer survey has resulted in the evaluation of portability support and indicated the possibilities and difficulties of improvements.

  2. High performance channel injection sealant invention abstract

    NASA Technical Reports Server (NTRS)

    Rosser, R. W.; Basiulis, D. I.; Salisbury, D. P. (Inventor)

    1982-01-01

    High performance channel sealant is based on NASA patented cyano and diamidoximine-terminated perfluoroalkylene ether prepolymers that are thermally condensed and cross linked. The sealant contains asbestos and, in its preferred embodiments, Lithofrax, to lower its thermal expansion coefficient and a phenolic metal deactivator. Extensive evaluation shows the sealant is extremely resistant to thermal degradation with an onset point of 280 C. The materials have a volatile content of 0.18%, excellent flexibility, and adherence properties, and fuel resistance. No corrosibility to aluminum or titanium was observed.

  3. Preventing distortion of quick couplers of hoses of central pipe lines--a cheap and simple method.

    PubMed

    Kamath, S K; Patil, A V

    1995-01-01

    A cheap and practical approach of steel chains attached to the station outlet quick couplers helps in maintaining the shape of the quick couplers and ensures their effective functioning over a long period of time and avoids mishap of connection due to damage of these couplers. PMID:10740701

  4. Implementing an Affordable High-Performance Computing for Teaching-Oriented Computer Science Curriculum

    ERIC Educational Resources Information Center

    Abuzaghleh, Omar; Goldschmidt, Kathleen; Elleithy, Yasser; Lee, Jeongkyu

    2013-01-01

    With the advances in computing power, high-performance computing (HPC) platforms have had an impact on not only scientific research in advanced organizations but also computer science curriculum in the educational community. For example, multicore programming and parallel systems are highly desired courses in the computer science major. However,…

  5. InfoMall: An Innovative Strategy for High-Performance Computing and Communications Applications Development.

    ERIC Educational Resources Information Center

    Mills, Kim; Fox, Geoffrey

    1994-01-01

    Describes the InfoMall, a program led by the Northeast Parallel Architectures Center (NPAC) at Syracuse University (New York). The InfoMall features a partnership of approximately 24 organizations offering linked programs in High Performance Computing and Communications (HPCC) technology integration, software development, marketing, education and…

  6. High performance compression of science data

    NASA Technical Reports Server (NTRS)

    Storer, James A.; Cohn, Martin

    1994-01-01

    Two papers make up the body of this report. One presents a single-pass adaptive vector quantization algorithm that learns a codebook of variable size and shape entries; the authors present experiments on a set of test images showing that with no training or prior knowledge of the data, for a given fidelity, the compression achieved typically equals or exceeds that of the JPEG standard. The second paper addresses motion compensation, one of the most effective techniques used in the interframe data compression. A parallel block-matching algorithm for estimating interframe displacement of blocks with minimum error is presented. The algorithm is designed for a simple parallel architecture to process video in real time.

  7. High Performance Compression of Science Data

    NASA Technical Reports Server (NTRS)

    Storer, James A.; Carpentieri, Bruno; Cohn, Martin

    1994-01-01

    Two papers make up the body of this report. One presents a single-pass adaptive vector quantization algorithm that learns a codebook of variable size and shape entries; the authors present experiments on a set of test images showing that with no training or prior knowledge of the data, for a given fidelity, the compression achieved typically equals or exceeds that of the JPEG standard. The second paper addresses motion compensation, one of the most effective techniques used in interframe data compression. A parallel block-matching algorithm for estimating interframe displacement of blocks with minimum error is presented. The algorithm is designed for a simple parallel architecture to process video in real time.

  8. GAMMA: a high performance dataflow database machine

    SciTech Connect

    DeWitt, D.J.; Gerber, R.H.; Graefe, G.; Heytens, M.L.; Kumar, K.B.; Muralikrishna, M.

    1986-03-01

    In this paper, the design, implementation techniques, and initial performance evaluation of Gamma are presented. Gamma is a new relational database machine that exploits dataflow query processing techniques. Ganma is a fully operational prototype consisting of 20 VAX 11/750 computers. The design of Gamma is based on an earlier multiprocessor database machine prototype (DIRECT) and several years of subsequent research on the problems raised by the DIRECT prototype. In addition to demonstrating that parallelism can really be made to work in a database machine context, the Gamma prototype shows how parallelism can be controlled with minimal control overhead through a combination of the use of algorithms based on hashing and the pipelining of data between processes. Except for 2 messages to initiate each operator of a query tree and 1 message when the operator terminates, the execution of a query is entirely self-scheduling. 52 refs., 12 figs.

  9. Parallel rendering

    NASA Technical Reports Server (NTRS)

    Crockett, Thomas W.

    1995-01-01

    This article provides a broad introduction to the subject of parallel rendering, encompassing both hardware and software systems. The focus is on the underlying concepts and the issues which arise in the design of parallel rendering algorithms and systems. We examine the different types of parallelism and how they can be applied in rendering applications. Concepts from parallel computing, such as data decomposition, task granularity, scalability, and load balancing, are considered in relation to the rendering problem. We also explore concepts from computer graphics, such as coherence and projection, which have a significant impact on the structure of parallel rendering algorithms. Our survey covers a number of practical considerations as well, including the choice of architectural platform, communication and memory requirements, and the problem of image assembly and display. We illustrate the discussion with numerous examples from the parallel rendering literature, representing most of the principal rendering methods currently used in computer graphics.

  10. Sound pressure in insert earphone couplers and real ears.

    PubMed

    Burkhard, M D; Sachs, R M

    1977-12-01

    It is known that sound pressure, measured in couplers via a probe-tube microphone, often shows a pressure vs frequency response that drops sharply at a single frequency. In this study sound pressure was theoretically determined at various locations within a hard-walled cylindrical cavity, driven by a constant-volume velocity source with circular symmetry. At each location in the volume, a transfer impedance was defined as the ratio of pressure to inlet-volume velocity. In the region around the inlet, the transfer impedance passes through zero as it changes from negative to positive reactance with increasing frequency. Two hard-walled cavity examples were examined in detail (1) the main cavity of a 2-cm3 HA-2 coupler, and (2) a cavity having dimensions approximately equal to the occluded ear canal between an ear-mold tip and the eardrum. Contours of constant minimum sound pressure vs frequency are given for these two cylindrical volumes with experimental verification. Implications for probe microphone calibration and measurement of sound pressure in ears are discussed. PMID:604691

  11. Supersymmetry-Inspired Non-Hermitian Optical Couplers

    PubMed Central

    Principe, Maria; Castaldi, Giuseppe; Consales, Marco; Cusano, Andrea; Galdi, Vincenzo

    2015-01-01

    Supersymmetry has been shown to provide a systematic and effective framework for generating classes of isospectral optical structures featuring perfectly-phase-matched modes, with the exception of one (fundamental) mode which can be removed. More recently, this approach has been extended to non-Hermitian scenarios characterized by spatially-modulated distributions of optical loss and gain, in order to allow the removal of higher-order modes as well. In this paper, we apply this approach to the design of non-Hermitian optical couplers with higher-order mode-selection functionalities, with potential applications to mode-division multiplexing in optical links. In particular, we highlight the critical role of the coupling between non-Hermitian optical waveguides, which generally induces a phase transition to a complex eigenspectrum, thereby hindering the targeted mode-selection functionality. With the specific example of an optical coupler that selects the second-order mode of a given waveguide, we illustrate the aforementioned limitations and propose possible strategies to overcome them, bearing in mind the practical feasibility of the gain levels required. PMID:25708887

  12. Graphene-based terahertz tunable plasmonic directional coupler

    SciTech Connect

    He, Meng-Dong Wang, Kai-Jun; Wang, Lei; Li, Jian-Bo; Liu, Jian-Qiang; Huang, Zhen-Rong; Wang, Lingling; Wang, Lin; Hu, Wei-Da; Chen, Xiaoshuang

    2014-08-25

    We propose and numerically analyze a terahertz tunable plasmonic directional coupler which is composed of a thin metal film with a nanoscale slit, dielectric grating, a graphene sheet, and a dielectric substrate. The slit is employed to generate surface plasmon polaritons (SPPs), and the metal-dielectric grating-graphene-dielectric constructs a Bragg reflector, whose bandgap can be tuned over a wide frequency range by a small change in the Fermi energy level of graphene. As a graphene-based Bragg reflector is formed on one side of the slit, the structure enables SPP waves to be unidirectionally excited on the other side of the slit due to SPP interference, and the SPP waves in the Bragg reflector can be efficiently switched on and off by tuning the graphene's Fermi energy level. By introducing two optimized graphene-based Bragg reflectors into opposite sides of the slit, SPP waves can be guided to different Bragg reflectors at different Fermi energy levels, thus achieving a tunable bidirectional coupler.

  13. The impacts of ageing effects due to radiation burden on optical fiber couplers

    NASA Astrophysics Data System (ADS)

    Perecar, F.; Marcinka, O.; Bednarek, L.; Lucki, M.; Liner, A.; Hajek, L.; Papes, M.; Jaros, J.; Vasinek, V.

    2015-08-01

    The paper discuss about accelerated ageing of optical fiber elements in their burdened with gamma radiation. In addition to the destruction of coating materials, gamma radiation has its effect on the internal structure of the optical fiber. It is necessary to specify the changes in the optical coupler and find out why these changes occur. This article contains experimental measurement of the impact of gamma radiation Cobalt-60 on the optical couplers of various split performance ratio. The couplers were exposed to gradually increasing doses of 60Co. Measurements are focused on the overall distribution of the energy in the core and cladding various branches of SM optical fiber couplers. This article focuses on applied research and experimental development of resources for safety operation of optical networks since monitoring of ageing substantially contributes to its security. It addresses issues of accelerated ageing of optical fiber elements in their burdened with gamma radiation. How does radiation energy of gamma radiation influence optical network elements? This effect is explored just very little bit and is yet another unanswered question. In addition to the destruction of coating materials, gamma radiation has its effect on the internal structure of the optical fiber. It is necessary to specify the changes in the optical coupler and find out why these changes occur. This article contains experimental measurement of the impact of gamma radiation Cobalt-60 on the optical couplers of various split performance ratio. Optical passive components, couplers, were exposed to gradually increasing doses of 60Co. Measurements are focused on the overall distribution of the energy of LP01 mode in the core and cladding various branches of SM optical fiber couplers. Graphical and mathematical detect changes in the dissemination of energy coupler after single doses of gamma radiation are useful to understand the phenomenon of accelerated ageing elements of optical networks in

  14. Stabilizing mechanism and running behavior of couplers on heavy haul trains

    NASA Astrophysics Data System (ADS)

    Xu, Ziqiang; Wu, Qing; Luo, Shihui; Ma, Weihua; Dong, Xiaoqing

    2014-11-01

    Published studies in regard to coupler systems have been mainly focused on the manufacturing process or coupler strength issues. With the ever increasing of tonnage and length of heavy haul trains, lateral in-train forces generated by longitudinal in-train forces and coupler rotations have become a more and more significant safety issue for heavy haul train operations. Derailments caused by excessive lateral in-train forces are frequently reported. This article studies two typical coupler systems used on heavy haul locomotives. Their structures and stabilizing mechanism are analyzed before the corresponding models are developed. Coupler systems models are featured by two distinct stabilizing mechanism models and draft gear models with hysteresis considered. A model set which consists of four locomotives and three coupler systems is developed to study the rotational behavior of different coupler systems and their implications for locomotive dynamics. Simulated results indicate that when the locomotives are equipped with the type B coupler system, locomotives can meet the dynamics standard on tangent tracks; while the dynamics performance on curved tracks is very poor. The maximum longitudinal in-train force for locomotives equipped with the type B coupler system is 2000 kN. Simulations revealed a distinct trend for the type A coupler system. Locomotive dynamics are poorer for the type A case when locomotives are running on tangent tracks, while the dynamics are better for the type A case when locomotives are running on curved tracks. Theoretical studies and simulations carried out in this article suggest that a combination of the two types of stabilizing mechanism can result in a good design which can significantly decrease the relevant derailments.

  15. Design and implementation of a high performance network security processor

    NASA Astrophysics Data System (ADS)

    Wang, Haixin; Bai, Guoqiang; Chen, Hongyi

    2010-03-01

    The last few years have seen many significant progresses in the field of application-specific processors. One example is network security processors (NSPs) that perform various cryptographic operations specified by network security protocols and help to offload the computation intensive burdens from network processors (NPs). This article presents a high performance NSP system architecture implementation intended for both internet protocol security (IPSec) and secure socket layer (SSL) protocol acceleration, which are widely employed in virtual private network (VPN) and e-commerce applications. The efficient dual one-way pipelined data transfer skeleton and optimised integration scheme of the heterogenous parallel crypto engine arrays lead to a Gbps rate NSP, which is programmable with domain specific descriptor-based instructions. The descriptor-based control flow fragments large data packets and distributes them to the crypto engine arrays, which fully utilises the parallel computation resources and improves the overall system data throughput. A prototyping platform for this NSP design is implemented with a Xilinx XC3S5000 based FPGA chip set. Results show that the design gives a peak throughput for the IPSec ESP tunnel mode of 2.85 Gbps with over 2100 full SSL handshakes per second at a clock rate of 95 MHz.

  16. High-performance monolithic CMOS detectors for space applications

    NASA Astrophysics Data System (ADS)

    Saint-Pe, Olivier; Tulet, Michel; Davancens, Robert; Larnaudie, Franck; Vignon, Bruno; Magnan, Pierre; Farre, Jean A.; Corbiere, Franck; Martin-Gonthier, Philippe

    2001-12-01

    During the last 10 years, research about CMOS image sensors (also called APS - Active Pixel Sensors) has been intensively carried out, in order to offer an alternative to CCDs as image sensors. This is particularly the case for space applications as CMOS image sensors feature characteristics which are obviously of interest for flight hardware: parallel or semi-parallel architecture, on chip control and processing electronics, low power dissipation, high level of radiation tolerance... Many image sensor companies, institutes and laboratories have demonstrated the compatibility of CMOS image sensors with consumer applications: micro-cameras, video-conferencing, digital- still cameras. And recent designs have shown that APS is getting closer to the CCD in terms of performance level. However, he large majority of the existing products do not offer the specific features which are required for many space applications. ASTRIUM and SUPAERO/CIMI have decided to work together in view of developing CMOS image sensors dedicated to space business. After a brief presentation of the team organization for space image sensor design and production, the latest results of a high performances 512 X 512 pixels CMOS device characterization are presented with emphasis on the achieved electro-optical performance. Finally, the on going and short-term coming activities of the team are discussed.

  17. Enabling Efficient Climate Science Workflows in High Performance Computing Environments

    NASA Astrophysics Data System (ADS)

    Krishnan, H.; Byna, S.; Wehner, M. F.; Gu, J.; O'Brien, T. A.; Loring, B.; Stone, D. A.; Collins, W.; Prabhat, M.; Liu, Y.; Johnson, J. N.; Paciorek, C. J.

    2015-12-01

    A typical climate science workflow often involves a combination of acquisition of data, modeling, simulation, analysis, visualization, publishing, and storage of results. Each of these tasks provide a myriad of challenges when running on a high performance computing environment such as Hopper or Edison at NERSC. Hurdles such as data transfer and management, job scheduling, parallel analysis routines, and publication require a lot of forethought and planning to ensure that proper quality control mechanisms are in place. These steps require effectively utilizing a combination of well tested and newly developed functionality to move data, perform analysis, apply statistical routines, and finally, serve results and tools to the greater scientific community. As part of the CAlibrated and Systematic Characterization, Attribution and Detection of Extremes (CASCADE) project we highlight a stack of tools our team utilizes and has developed to ensure that large scale simulation and analysis work are commonplace and provide operations that assist in everything from generation/procurement of data (HTAR/Globus) to automating publication of results to portals like the Earth Systems Grid Federation (ESGF), all while executing everything in between in a scalable environment in a task parallel way (MPI). We highlight the use and benefit of these tools by showing several climate science analysis use cases they have been applied to.

  18. High-performance electron tomography of complex biological specimens.

    PubMed

    Fernández, José-Jesús; Lawrence, Albert F; Roca, Javier; García, Inmaculada; Ellisman, Mark H; Carazo, José-María

    2002-01-01

    We have evaluated reconstruction methods using smooth basis functions in the electron tomography of complex biological specimens. In particular, we have investigated series expansion methods, with special emphasis on parallel computation. Among the methods investigated, the component averaging techniques have proven to be most efficient and have generally shown fast convergence rates. The use of smooth basis functions provides the reconstruction algorithms with an implicit regularization mechanism, very appropriate for noisy conditions. Furthermore, we have applied high-performance computing (HPC) techniques to address the computational requirements demanded by the reconstruction of large volumes. One of the standard techniques in parallel computing, domain decomposition, has yielded an effective computational algorithm which hides the latencies due to interprocessor communication. We present comparisons with weighted back-projection (WBP), one of the standard reconstruction methods in the areas of computational demand and reconstruction quality under noisy conditions. These techniques yield better results, according to objective measures of quality, than the weighted backprojection techniques after a very few iterations. As a consequence, the combination of efficient iterative algorithms and HPC techniques has proven to be well suited to the reconstruction of large biological specimens in electron tomography, yielding solutions in reasonable computation times. PMID:12160697

  19. High-performance mass storage system for workstations

    NASA Technical Reports Server (NTRS)

    Chiang, T.; Tang, Y.; Gupta, L.; Cooperman, S.

    1993-01-01

    Reduced Instruction Set Computer (RISC) workstations and Personnel Computers (PC) are very popular tools for office automation, command and control, scientific analysis, database management, and many other applications. However, when using Input/Output (I/O) intensive applications, the RISC workstations and PC's are often overburdened with the tasks of collecting, staging, storing, and distributing data. Also, by using standard high-performance peripherals and storage devices, the I/O function can still be a common bottleneck process. Therefore, the high-performance mass storage system, developed by Loral AeroSys' Independent Research and Development (IR&D) engineers, can offload a RISC workstation of I/O related functions and provide high-performance I/O functions and external interfaces. The high-performance mass storage system has the capabilities to ingest high-speed real-time data, perform signal or image processing, and stage, archive, and distribute the data. This mass storage system uses a hierarchical storage structure, thus reducing the total data storage cost, while maintaining high-I/O performance. The high-performance mass storage system is a network of low-cost parallel processors and storage devices. The nodes in the network have special I/O functions such as: SCSI controller, Ethernet controller, gateway controller, RS232 controller, IEEE488 controller, and digital/analog converter. The nodes are interconnected through high-speed direct memory access links to form a network. The topology of the network is easily reconfigurable to maximize system throughput for various applications. This high-performance mass storage system takes advantage of a 'busless' architecture for maximum expandability. The mass storage system consists of magnetic disks, a WORM optical disk jukebox, and an 8mm helical scan tape to form a hierarchical storage structure. Commonly used files are kept in the magnetic disk for fast retrieval. The optical disks are used as archive

  20. DOE High Performance Concentrator PV Project

    SciTech Connect

    McConnell, R.; Symko-Davies, M.

    2005-08-01

    Much in demand are next-generation photovoltaic (PV) technologies that can be used economically to make a large-scale impact on world electricity production. The U.S. Department of Energy (DOE) initiated the High-Performance Photovoltaic (HiPerf PV) Project to substantially increase the viability of PV for cost-competitive applications so that PV can contribute significantly to both our energy supply and environment. To accomplish such results, the National Center for Photovoltaics (NCPV) directs in-house and subcontracted research in high-performance polycrystalline thin-film and multijunction concentrator devices with the goal of enabling progress of high-efficiency technologies toward commercial-prototype products. We will describe the details of the subcontractor and in-house progress in exploring and accelerating pathways of III-V multijunction concentrator solar cells and systems toward their long-term goals. By 2020, we anticipate that this project will have demonstrated 33% system efficiency and a system price of $1.00/Wp for concentrator PV systems using III-V multijunction solar cells with efficiencies over 41%.

  1. Management issues for high performance storage systems

    SciTech Connect

    Louis, S.; Burris, R.

    1995-03-01

    Managing distributed high-performance storage systems is complex and, although sharing common ground with traditional network and systems management, presents unique storage-related issues. Integration technologies and frameworks exist to help manage distributed network and system environments. Industry-driven consortia provide open forums where vendors and users cooperate to leverage solutions. But these new approaches to open management fall short addressing the needs of scalable, distributed storage. We discuss the motivation and requirements for storage system management (SSM) capabilities and describe how SSM manages distributed servers and storage resource objects in the High Performance Storage System (HPSS), a new storage facility for data-intensive applications and large-scale computing. Modem storage systems, such as HPSS, require many SSM capabilities, including server and resource configuration control, performance monitoring, quality of service, flexible policies, file migration, file repacking, accounting, and quotas. We present results of initial HPSS SSM development including design decisions and implementation trade-offs. We conclude with plans for follow-on work and provide storage-related recommendations for vendors and standards groups seeking enterprise-wide management solutions.

  2. A High Performance COTS Based Computer Architecture

    NASA Astrophysics Data System (ADS)

    Patte, Mathieu; Grimoldi, Raoul; Trautner, Roland

    2014-08-01

    Using Commercial Off The Shelf (COTS) electronic components for space applications is a long standing idea. Indeed the difference in processing performance and energy efficiency between radiation hardened components and COTS components is so important that COTS components are very attractive for use in mass and power constrained systems. However using COTS components in space is not straightforward as one must account with the effects of the space environment on the COTS components behavior. In the frame of the ESA funded activity called High Performance COTS Based Computer, Airbus Defense and Space and its subcontractor OHB CGS have developed and prototyped a versatile COTS based architecture for high performance processing. The rest of the paper is organized as follows: in a first section we will start by recapitulating the interests and constraints of using COTS components for space applications; then we will briefly describe existing fault mitigation architectures and present our solution for fault mitigation based on a component called the SmartIO; in the last part of the paper we will describe the prototyping activities executed during the HiP CBC project.

  3. Strategy Guideline: Partnering for High Performance Homes

    SciTech Connect

    Prahl, D.

    2013-01-01

    High performance houses require a high degree of coordination and have significant interdependencies between various systems in order to perform properly, meet customer expectations, and minimize risks for the builder. Responsibility for the key performance attributes is shared across the project team and can be well coordinated through advanced partnering strategies. For high performance homes, traditional partnerships need to be matured to the next level and be expanded to all members of the project team including trades, suppliers, manufacturers, HERS raters, designers, architects, and building officials as appropriate. In an environment where the builder is the only source of communication between trades and consultants and where relationships are, in general, adversarial as opposed to cooperative, the chances of any one building system to fail are greater. Furthermore, it is much harder for the builder to identify and capitalize on synergistic opportunities. Partnering can help bridge the cross-functional aspects of the systems approach and achieve performance-based criteria. Critical success factors for partnering include support from top management, mutual trust, effective and open communication, effective coordination around common goals, team building, appropriate use of an outside facilitator, a partnering charter progress toward common goals, an effective problem-solving process, long-term commitment, continuous improvement, and a positive experience for all involved.

  4. A Linux Workstation for High Performance Graphics

    NASA Technical Reports Server (NTRS)

    Geist, Robert; Westall, James

    2000-01-01

    The primary goal of this effort was to provide a low-cost method of obtaining high-performance 3-D graphics using an industry standard library (OpenGL) on PC class computers. Previously, users interested in doing substantial visualization or graphical manipulation were constrained to using specialized, custom hardware most often found in computers from Silicon Graphics (SGI). We provided an alternative to expensive SGI hardware by taking advantage of third-party, 3-D graphics accelerators that have now become available at very affordable prices. To make use of this hardware our goal was to provide a free, redistributable, and fully-compatible OpenGL work-alike library so that existing bodies of code could simply be recompiled. for PC class machines running a free version of Unix. This should allow substantial cost savings while greatly expanding the population of people with access to a serious graphics development and viewing environment. This should offer a means for NASA to provide a spectrum of graphics performance to its scientists, supplying high-end specialized SGI hardware for high-performance visualization while fulfilling the requirements of medium and lower performance applications with generic, off-the-shelf components and still maintaining compatibility between the two.

  5. High-performance computing for airborne applications

    SciTech Connect

    Quinn, Heather M; Manuzzato, Andrea; Fairbanks, Tom; Dallmann, Nicholas; Desgeorges, Rose

    2010-06-28

    Recently, there has been attempts to move common satellite tasks to unmanned aerial vehicles (UAVs). UAVs are significantly cheaper to buy than satellites and easier to deploy on an as-needed basis. The more benign radiation environment also allows for an aggressive adoption of state-of-the-art commercial computational devices, which increases the amount of data that can be collected. There are a number of commercial computing devices currently available that are well-suited to high-performance computing. These devices range from specialized computational devices, such as field-programmable gate arrays (FPGAs) and digital signal processors (DSPs), to traditional computing platforms, such as microprocessors. Even though the radiation environment is relatively benign, these devices could be susceptible to single-event effects. In this paper, we will present radiation data for high-performance computing devices in a accelerated neutron environment. These devices include a multi-core digital signal processor, two field-programmable gate arrays, and a microprocessor. From these results, we found that all of these devices are suitable for many airplane environments without reliability problems.

  6. Improving estimations of greenhouse gas transfer velocities by atmosphere-ocean couplers in Earth-System and regional models

    NASA Astrophysics Data System (ADS)

    Vieira, V. M. N. C. S.; Sahlée, E.; Jurus, P.; Clementi, E.; Pettersson, H.; Mateus, M.

    2015-09-01

    Earth-System and regional models, forecasting climate change and its impacts, simulate atmosphere-ocean gas exchanges using classical yet too simple generalizations relying on wind speed as the sole mediator while neglecting factors as sea-surface agitation, atmospheric stability, current drag with the bottom, rain and surfactants. These were proved fundamental for accurate estimates, particularly in the coastal ocean, where a significant part of the atmosphere-ocean greenhouse gas exchanges occurs. We include several of these factors in a customizable algorithm proposed for the basis of novel couplers of the atmospheric and oceanographic model components. We tested performances with measured and simulated data from the European coastal ocean, having found our algorithm to forecast greenhouse gas exchanges largely different from the forecasted by the generalization currently in use. Our algorithm allows calculus vectorization and parallel processing, improving computational speed roughly 12× in a single cpu core, an essential feature for Earth-System models applications.

  7. High performance computations using dynamical nucleation theory

    NASA Astrophysics Data System (ADS)

    Windus, T. L.; Kathmann, S. M.; Crosby, L. D.

    2008-07-01

    Chemists continue to explore the use of very large computations to perform simulations that describe the molecular level physics of critical challenges in science. In this paper, we describe the Dynamical Nucleation Theory Monte Carlo (DNTMC) model - a model for determining molecular scale nucleation rate constants - and its parallel capabilities. The potential for bottlenecks and the challenges to running on future petascale or larger resources are delineated. A 'master-slave' solution is proposed to scale to the petascale and will be developed in the NWChem software. In addition, mathematical and data analysis challenges are described.

  8. High-performance capillary electrophoresis of histones

    SciTech Connect

    Gurley, L.R.; London, J.E.; Valdez, J.G.

    1991-01-01

    A high performance capillary electrophoresis (HPCE) system has been developed for the fractionation of histones. This system involves electroinjection of the sample and electrophoresis in a 0.1M phosphate buffer at pH 2.5 in a 50 {mu}m {times} 35 cm coated capillary. Electrophoresis was accomplished in 9 minutes separating a whole histone preparation into its components in the following order of decreasing mobility; (MHP) H3, H1 (major variant), H1 (minor variant), (LHP) H3, (MHP) H2A (major variant), (LHP) H2A, H4, H2B, (MHP) H2A (minor variant) where MHP is the more hydrophobic component and LHP is the less hydrophobic component. This order of separation is very different from that found in acid-urea polyacrylamide gel electrophoresis and in reversed-phase HPLC and, thus, brings the histone biochemist a new dimension for the qualitative analysis of histone samples. 27 refs., 8 figs.

  9. How to create high-performing teams.

    PubMed

    Lam, Samuel M

    2010-02-01

    This article is intended to discuss inspirational aspects on how to lead a high-performance team. Cogent topics discussed include how to hire staff through methods of "topgrading" with reference to Geoff Smart and "getting the right people on the bus" referencing Jim Collins' work. In addition, once the staff is hired, this article covers how to separate the "eagles from the ducks" and how to inspire one's staff by creating the right culture with suggestions for further reading by Don Miguel Ruiz (The four agreements) and John Maxwell (21 Irrefutable laws of leadership). In addition, Simon Sinek's concept of "Start with Why" is elaborated to help a leader know what the core element should be with any superior culture. PMID:20127598

  10. High performance stepper motors for space mechanisms

    NASA Astrophysics Data System (ADS)

    Sega, Patrick; Estevenon, Christine

    1995-05-01

    Hybrid stepper motors are very well adapted to high performance space mechanisms. They are very simple to operate and are often used for accurate positioning and for smooth rotations. In order to fulfill these requirements, the motor torque, its harmonic content, and the magnetic parasitic torque have to be properly designed. Only finite element computations can provide enough accuracy to determine the toothed structures' magnetic permeance, whose derivative function leads to the torque. It is then possible to design motors with a maximum torque capability or with the most reduced torque harmonic content (less than 3 percent of fundamental). These later motors are dedicated to applications where a microstep or a synchronous mode is selected for minimal dynamic disturbances. In every case, the capability to convert electrical power into torque is much higher than on DC brushless motors.

  11. High performance stepper motors for space mechanisms

    NASA Technical Reports Server (NTRS)

    Sega, Patrick; Estevenon, Christine

    1995-01-01

    Hybrid stepper motors are very well adapted to high performance space mechanisms. They are very simple to operate and are often used for accurate positioning and for smooth rotations. In order to fulfill these requirements, the motor torque, its harmonic content, and the magnetic parasitic torque have to be properly designed. Only finite element computations can provide enough accuracy to determine the toothed structures' magnetic permeance, whose derivative function leads to the torque. It is then possible to design motors with a maximum torque capability or with the most reduced torque harmonic content (less than 3 percent of fundamental). These later motors are dedicated to applications where a microstep or a synchronous mode is selected for minimal dynamic disturbances. In every case, the capability to convert electrical power into torque is much higher than on DC brushless motors.

  12. High performance robotic traverse of desert terrain.

    SciTech Connect

    Whittaker, William

    2004-09-01

    This report presents tentative innovations to enable unmanned vehicle guidance for a class of off-road traverse at sustained speeds greater than 30 miles per hour. Analyses and field trials suggest that even greater navigation speeds might be achieved. The performance calls for innovation in mapping, perception, planning and inertial-referenced stabilization of components, hosted aboard capable locomotion. The innovations are motivated by the challenge of autonomous ground vehicle traverse of 250 miles of desert terrain in less than 10 hours, averaging 30 miles per hour. GPS coverage is assumed to be available with localized blackouts. Terrain and vegetation are assumed to be akin to that of the Mojave Desert. This terrain is interlaced with networks of unimproved roads and trails, which are a key to achieving the high performance mapping, planning and navigation that is presented here.

  13. High performance railgun barrels for laboratory use

    NASA Astrophysics Data System (ADS)

    Bauer, David P.; Newman, Duane C.

    1993-01-01

    High performance low-cost, laboratory railgun barrels are now available, comprised of an inherently stiff containment structure which surrounds the bore components machined from 'off the-shelf' materials. The shape of the containment structure was selected to make the barrel inherently stiff. The structure consists of stainless steel laminations which do not compromise the electrical efficiency of the railgun. The modular design enhances the utility of the barrel, as it is easy to service between shots, and can be 're-cored' to produce different configurations and sizes using the same structure. We have produced barrels ranging from 15 mm to 90 mm square bore, a 30 mm round bore, and in lengths varying from 0.25 meters to 10 meters long. Successful tests with both plasma and solid metal armatures have demonstrated the versatility and performance of this design.

  14. Advanced solidification system using high performance cement

    SciTech Connect

    Kikuchi, Makoto; Matsuda, Masami; Nishi, Takashi; Tsuchiya, Hiroyuki; Izumida, Tatsuo

    1995-12-31

    Advanced cement solidification is proposed for the solidification of radioactive waste such as spent ion exchange resin, incineration ash and liquid waste. A new, high performance cement has been developed to raise volume reduction efficiency and lower radioactivity release into the environment. It consists of slag cement, reinforcing fiber, natural zeolite and lithium nitrate (LiNO{sub 3}). The fiber allows waste loading to be increased from 20 to 55kg-dry resin/200L. The zeolite, whose main constituent is clinoptilolite, reduces cesium leachability from the waste form to about 1/10. Lithium nitrate prevents alkaline corrosion of the aluminum, contained in ash, and reduces hydrogen gas generation. Laboratory and full-scale pilot plant experiments were performed to evaluate properties of the waste form, using simulated wastes. Emphasis was laid on improvement of solidification of spent resin and ash.

  15. Development of a high performance peristaltic micropump

    NASA Astrophysics Data System (ADS)

    Pham, My; Goo, Nam Seo

    2008-03-01

    In this study, a high performance peristaltic micropump has been developed and investigated. The micropump has three cylinder chambers which are connected through micro-channels for high pumping pressure performance. A circular-shaped mini LIPCA has been designed and manufactured for actuating diaphragm. In this LIPCA, a 0.1mm thickness PZT ceramic is used as an active layer. As a result, the actuator has shown to produce large out of plane deflection and consumed low power. During the design process, a coupled field analysis was conducted to predict the actuating behavior of a diaphragm and pumping performance. MEMS technique was used to fabricate the peristaltic micropump. Pumping performance of the present micropump was investigated both numerically and experimentally. The present peristaltic micropump was shown to have higher performance than the same kind of micropump developed else where.

  16. High-Performance, Low Environmental Impact Refrigerants

    NASA Technical Reports Server (NTRS)

    McCullough, E. T.; Dhooge, P. M.; Glass, S. M.; Nimitz, J. S.

    2001-01-01

    Refrigerants used in process and facilities systems in the US include R-12, R-22, R-123, R-134a, R-404A, R-410A, R-500, and R-502. All but R-134a, R-404A, and R-410A contain ozone-depleting substances that will be phased out under the Montreal Protocol. Some of the substitutes do not perform as well as the refrigerants they are replacing, require new equipment, and have relatively high global warming potentials (GWPs). New refrigerants are needed that addresses environmental, safety, and performance issues simultaneously. In efforts sponsored by Ikon Corporation, NASA Kennedy Space Center (KSC), and the US Environmental Protection Agency (EPA), ETEC has developed and tested a new class of refrigerants, the Ikon (registered) refrigerants, based on iodofluorocarbons (IFCs). These refrigerants are nonflammable, have essentially zero ozone-depletion potential (ODP), low GWP, high performance (energy efficiency and capacity), and can be dropped into much existing equipment.

  17. Fiber-optic couplers. January 1973-February 1988 (citations from the NTIS data base). Report for January 1973-February 1988

    SciTech Connect

    Not Available

    1988-03-01

    This bibliography contains citations concerning the design, fabrication, analysis, performance evaluation, and applications of fiber-optic couplers. Topics include optical coupling for fiber-optic transmission lines, frequency and wavelength division multiplexing, multiwavelength coupler-decouplers, single mode and multimode couplers, and fiber-optic gyroscope applications. Various types of couplers are examined including waveguide, star, access, duplex, data bus, passive, tee, and holographic. Patented fiber-optic devices using couplers are included. Citations concerning fiber-optic connectors are excluded and examined in a separate bibliography. (Contains 218 citations fully indexed and including a title list.)

  18. High performance anode for advanced Li batteries

    SciTech Connect

    Lake, Carla

    2015-11-02

    The overall objective of this Phase I SBIR effort was to advance the manufacturing technology for ASI’s Si-CNF high-performance anode by creating a framework for large volume production and utilization of low-cost Si-coated carbon nanofibers (Si-CNF) for the battery industry. This project explores the use of nano-structured silicon which is deposited on a nano-scale carbon filament to achieve the benefits of high cycle life and high charge capacity without the consequent fading of, or failure in the capacity resulting from stress-induced fracturing of the Si particles and de-coupling from the electrode. ASI’s patented coating process distinguishes itself from others, in that it is highly reproducible, readily scalable and results in a Si-CNF composite structure containing 25-30% silicon, with a compositionally graded interface at the Si-CNF interface that significantly improve cycling stability and enhances adhesion of silicon to the carbon fiber support. In Phase I, the team demonstrated the production of the Si-CNF anode material can successfully be transitioned from a static bench-scale reactor into a fluidized bed reactor. In addition, ASI made significant progress in the development of low cost, quick testing methods which can be performed on silicon coated CNFs as a means of quality control. To date, weight change, density, and cycling performance were the key metrics used to validate the high performance anode material. Under this effort, ASI made strides to establish a quality control protocol for the large volume production of Si-CNFs and has identified several key technical thrusts for future work. Using the results of this Phase I effort as a foundation, ASI has defined a path forward to commercialize and deliver high volume and low-cost production of SI-CNF material for anodes in Li-ion batteries.

  19. Small-Scale High-Performance Optics

    SciTech Connect

    WILSON, CHRISTOPHER W.; LEGER, CHRIS L.; SPLETZER, BARRY L.

    2002-06-01

    Historically, high resolution, high slew rate optics have been heavy, bulky, and expensive. Recent advances in MEMS (Micro Electro Mechanical Systems) technology and micro-machining may change this. Specifically, the advent of steerable sub-millimeter sized mirror arrays could provide the breakthrough technology for producing very small-scale high-performance optical systems. For example, an array of steerable MEMS mirrors could be the building blocks for a Fresnel mirror of controllable focal length and direction of view. When coupled with a convex parabolic mirror the steerable array could realize a micro-scale pan, tilt and zoom system that provides full CCD sensor resolution over the desired field of view with no moving parts (other than MEMS elements). This LDRD provided the first steps towards the goal of a new class of small-scale high-performance optics based on MEMS technology. A large-scale, proof of concept system was built to demonstrate the effectiveness of an optical configuration applicable to producing a small-scale (< 1cm) pan and tilt imaging system. This configuration consists of a color CCD imager with a narrow field of view lens, a steerable flat mirror, and a convex parabolic mirror. The steerable flat mirror directs the camera's narrow field of view to small areas of the convex mirror providing much higher pixel density in the region of interest than is possible with a full 360 deg. imaging system. Improved image correction (dewarping) software based on texture mapping images to geometric solids was developed. This approach takes advantage of modern graphics hardware and provides a great deal of flexibility for correcting images from various mirror shapes. An analytical evaluation of blur spot size and axi-symmetric reflector optimization were performed to address depth of focus issues that occurred in the proof of concept system. The resulting equations will provide the tools for developing future system designs.

  20. Multimode Directional Coupler for Utilization of Harmonic Frequencies from TWTAs

    NASA Technical Reports Server (NTRS)

    Simmons, Rainee N.; Wintucky, Edwin G.

    2013-01-01

    A novel waveguide multimode directional coupler (MDC) intended for the measurement and potential utilization of the second and higher order harmonic frequencies from high-power traveling wave tube amplifiers (TWTAs) has been successfully designed, fabricated, and tested. The design is based on the characteristic multiple propagation modes of the electrical and magnetic field components of electromagnetic waves in a rectangular waveguide. The purpose was to create a rugged, easily constructed, more efficient waveguide- based MDC for extraction and exploitation of the second harmonic signal from the RF output of high-power TWTs used for space communications. The application would be a satellitebased beacon source needed for Qband and V/W-band atmospheric propagation studies. The MDC could function as a CW narrow-band source or as a wideband source for study of atmospheric group delay effects on highdata- rate links. The MDC is fabricated from two sections of waveguide - a primary one for the fundamental frequency and a secondary waveguide for the second harmonic - that are joined together such that the second harmonic higher order modes are selectively coupled via precision- machined slots for propagation in the secondary waveguide. In the TWTA output waveguide port, both the fundamental and the second harmonic signals are present. These signals propagate in the output waveguide as the dominant and higher order modes, respectively. By including an appropriate mode selective waveguide directional coupler, such as the MDC presented here at the output of the TWTA, the power at the second harmonic can be sampled and amplified to the power level needed for atmospheric propagation studies. The important conclusions from the preliminary test results for the multimode directional coupler are: (1) the second harmonic (Ka-band) can be measured and effectively separated from the fundamental (Ku-band) with no coupling of the latter, (2) power losses in the fundamental frequency

  1. High Performance Radiation Transport Simulations on TITAN

    SciTech Connect

    Baker, Christopher G; Davidson, Gregory G; Evans, Thomas M; Hamilton, Steven P; Jarrell, Joshua J; Joubert, Wayne

    2012-01-01

    In this paper we describe the Denovo code system. Denovo solves the six-dimensional, steady-state, linear Boltzmann transport equation, of central importance to nuclear technology applications such as reactor core analysis (neutronics), radiation shielding, nuclear forensics and radiation detection. The code features multiple spatial differencing schemes, state-of-the-art linear solvers, the Koch-Baker-Alcouffe (KBA) parallel-wavefront sweep algorithm for inverting the transport operator, a new multilevel energy decomposition method scaling to hundreds of thousands of processing cores, and a modern, novel code architecture that supports straightforward integration of new features. In this paper we discuss the performance of Denovo on the 10--20 petaflop ORNL GPU-based system, Titan. We describe algorithms and techniques used to exploit the capabilities of Titan's heterogeneous compute node architecture and the challenges of obtaining good parallel performance for this sparse hyperbolic PDE solver containing inherently sequential computations. Numerical results demonstrating Denovo performance on early Titan hardware are presented.

  2. High Performance Geostatistical Modeling of Biospheric Resources

    NASA Astrophysics Data System (ADS)

    Pedelty, J. A.; Morisette, J. T.; Smith, J. A.; Schnase, J. L.; Crosier, C. S.; Stohlgren, T. J.

    2004-12-01

    We are using parallel geostatistical codes to study spatial relationships among biospheric resources in several study areas. For example, spatial statistical models based on large- and small-scale variability have been used to predict species richness of both native and exotic plants (hot spots of diversity) and patterns of exotic plant invasion. However, broader use of geostastics in natural resource modeling, especially at regional and national scales, has been limited due to the large computing requirements of these applications. To address this problem, we implemented parallel versions of the kriging spatial interpolation algorithm. The first uses the Message Passing Interface (MPI) in a master/slave paradigm on an open source Linux Beowulf cluster, while the second is implemented with the new proprietary Xgrid distributed processing system on an Xserve G5 cluster from Apple Computer, Inc. These techniques are proving effective and provide the basis for a national decision support capability for invasive species management that is being jointly developed by NASA and the US Geological Survey.

  3. Fiber-chip edge coupler with large mode size for silicon photonic wire waveguides

    NASA Astrophysics Data System (ADS)

    Papes, Martin; Cheben, Pavel; Ye, Winnie N.; Schmid, Jens H.; Xu, Dan-Xia; Janz, Siegfried; Benedikovic, Daniel; Ramos, Carlos A.; Halir, Robert; Ortega-Moñux, Alejandro; Delâge, André; Vašinek, Vladimír.

    2015-05-01

    Fiber-chip edge couplers are extensively used in integrated optics as one of the key structures for coupling of light between planar waveguide circuits and optical fibers. In this work, a new fiber-chip edge coupler concept with large mode size for coupling to submicrometer silicon photonic wire waveguides is presented. The coupler allows direct coupling to conventional SMF-28 optical fiber and circumvents the need for lensed fibers. We demonstrate by simulations a 95% mode overlap between the mode at the chip facet and a high numerical aperture single mode optical fiber with 6 μm mode field diameter (MFD). We also demonstrate a modified design with 89% overlap between the mode at the chip facet and a standard SMF-28 fiber with 10.4 μm MFD. The coupler is designed for 220 nm silicon-oninsulator (SOI) platform. An important advantage of our coupler is that large mode size is obtained without the need to increase buried oxide (BOX) thickness, which in our design is set to 3 μm. This remarkable feature is achieved by implementing in the SiO2 upper cladding two thin high-index Si3N4 layers. The high-index layers increase the effective refractive index of the upper cladding layer near the facet and are gradually tapered out along the coupler to provide adiabatic mode transformation to the silicon wire waveguide. Simultaneously, the Si-wire waveguide is inversely tapered along the coupler. The mode overlap at the chip facet is studied using a vectorial 2D mode solver and the mode transformation along the coupler is studied by 3D Finite-Difference Time-Domain simulations. The couplers are optimized for operating with transverse electric (TE) polarization and the operating wavelength is centered at 1.55 μm.

  4. Improving UV Resistance of High Performance Fibers

    NASA Astrophysics Data System (ADS)

    Hassanin, Ahmed

    High performance fibers are characterized by their superior properties compared to the traditional textile fibers. High strength fibers have high modules, high strength to weight ratio, high chemical resistance, and usually high temperature resistance. It is used in application where superior properties are needed such as bulletproof vests, ropes and cables, cut resistant products, load tendons for giant scientific balloons, fishing rods, tennis racket strings, parachute cords, adhesives and sealants, protective apparel and tire cords. Unfortunately, Ultraviolet (UV) radiation causes serious degradation to the most of high performance fibers. UV lights, either natural or artificial, cause organic compounds to decompose and degrade, because the energy of the photons of UV light is high enough to break chemical bonds causing chain scission. This work is aiming at achieving maximum protection of high performance fibers using sheathing approaches. The sheaths proposed are of lightweight to maintain the advantage of the high performance fiber that is the high strength to weight ratio. This study involves developing three different types of sheathing. The product of interest that need be protected from UV is braid from PBO. First approach is extruding a sheath from Low Density Polyethylene (LDPE) loaded with different rutile TiO2 % nanoparticles around the braid from the PBO. The results of this approach showed that LDPE sheath loaded with 10% TiO2 by weight achieved the highest protection compare to 0% and 5% TiO2. The protection here is judged by strength loss of PBO. This trend noticed in different weathering environments, where the sheathed samples were exposed to UV-VIS radiations in different weatheromter equipments as well as exposure to high altitude environment using NASA BRDL balloon. The second approach is focusing in developing a protective porous membrane from polyurethane loaded with rutile TiO2 nanoparticles. Membrane from polyurethane loaded with 4

  5. Massively parallel visualization: Parallel rendering

    SciTech Connect

    Hansen, C.D.; Krogh, M.; White, W.

    1995-12-01

    This paper presents rendering algorithms, developed for massively parallel processors (MPPs), for polygonal, spheres, and volumetric data. The polygon algorithm uses a data parallel approach whereas the sphere and volume renderer use a MIMD approach. Implementations for these algorithms are presented for the Thinking Machines Corporation CM-5 MPP.

  6. An evaluation of Java's I/O capabilities for high-performance computing.

    SciTech Connect

    Dickens, P. M.; Thakur, R.

    2000-11-10

    Java is quickly becoming the preferred language for writing distributed applications because of its inherent support for programming on distributed platforms. In particular, Java provides compile-time and run-time security, automatic garbage collection, inherent support for multithreading, support for persistent objects and object migration, and portability. Given these significant advantages of Java, there is a growing interest in using Java for high-performance computing applications. To be successful in the high-performance computing domain, however, Java must have the capability to efficiently handle the significant I/O requirements commonly found in high-performance computing applications. While there has been significant research in high-performance I/O using languages such as C, C++, and Fortran, there has been relatively little research into the I/O capabilities of Java. In this paper, we evaluate the I/O capabilities of Java for high-performance computing. We examine several approaches that attempt to provide high-performance I/O--many of which are not obvious at first glance--and investigate their performance in both parallel and multithreaded environments. We also provide suggestions for expanding the I/O capabilities of Java to better support the needs of high-performance computing applications.

  7. NCI's Transdisciplinary High Performance Scientific Data Platform

    NASA Astrophysics Data System (ADS)

    Evans, Ben; Antony, Joseph; Bastrakova, Irina; Car, Nicholas; Cox, Simon; Druken, Kelsey; Evans, Bradley; Fraser, Ryan; Ip, Alex; Kemp, Carina; King, Edward; Minchin, Stuart; Larraondo, Pablo; Pugh, Tim; Richards, Clare; Santana, Fabiana; Smillie, Jon; Trenham, Claire; Wang, Jingbo; Wyborn, Lesley

    2016-04-01

    The Australian National Computational Infrastructure (NCI) manages Earth Systems data collections sourced from several domains and organisations onto a single High Performance Data (HPD) Node to further Australia's national priority research and innovation agenda. The NCI HPD Node has rapidly established its value, currently managing over 10 PBytes of datasets from collections that span a wide range of disciplines including climate, weather, environment, geoscience, geophysics, water resources and social sciences. Importantly, in order to facilitate broad user uptake, maximise reuse and enable transdisciplinary access through software and standardised interfaces, the datasets, associated information systems and processes have been incorporated into the design and operation of a unified platform that NCI has called, the National Environmental Research Data Interoperability Platform (NERDIP). The key goal of the NERDIP is to regularise data access so that it is easily discoverable, interoperable for different domains and enabled for high performance methods. It adopts and implements international standards and data conventions, and promotes scientific integrity within a high performance computing and data analysis environment. NCI has established a rich and flexible computing environment to access to this data, through the NCI supercomputer; a private cloud that supports both domain focused virtual laboratories and in-common interactive analysis interfaces; as well as remotely through scalable data services. Data collections of this importance must be managed with careful consideration of both their current use and the needs of the end-communities, as well as its future potential use, such as transitioning to more advanced software and improved methods. It is therefore critical that the data platform is both well-managed and trusted for stable production use (including transparency and reproducibility), agile enough to incorporate new technological advances and

  8. Compact Couplers for Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, Benjamin; Lin, M.C.; Schwartz, Brian; Byer, Robert; McGuinness, Christopher; Colby, Eric; England, Robert; Noble, Robert; Spencer, James; /SLAC

    2012-07-02

    Photonic crystal waveguides are promising candidates for laser-driven accelerator structures because of their ability to confine a speed-of-light mode in an all-dielectric structure. Because of the difference between the group velocity of the waveguide mode and the particle bunch velocity, fields must be coupled into the accelerating waveguide at frequent intervals. Therefore efficient, compact couplers are critical to overall accelerator efficiency. We present designs and simulations of high-efficiency coupling to the accelerating mode in a three-dimensional photonic crystal waveguide from a waveguide adjoining it at 90{sup o}. We discuss details of the computation and the resulting transmission. We include some background on the accelerator structure and photonic crystal-based optical acceleration in general.

  9. A two-state Raman coupler for coherent atom optics.

    PubMed

    Debs, J E; Döring, D; Robins, N P; Figl, C; Altin, P A; Close, J D

    2009-02-16

    We present results on a Raman laser-system that resonantly drives a closed two-photon transition between two levels in different hyperfine ground states of (87)Rb. The coupler is based on a novel optical design for producing two phase-coherent optical beams to drive a Raman transition. Operated as an outcoupler, it produces an atom laser in a single internal atomic state, with the lower divergence and increased brightness typical of a Raman outcoupler. Due to the optical nature of the outcoupling, the two-state outcoupler is an ideal candidate for transferring photon correlations onto atom-laser beams. As our laser system couples just two hyperfine ground states, it has also been used as an internal state beamsplitter, taking the next major step towards free space Ramsey interferometry with an atom laser. PMID:19219134

  10. Fiber optic highly over-coupled coupler sensors

    SciTech Connect

    Brown, D.A. ||; Chen, M.; Morse, T.F.

    1996-04-01

    We report on the development of prototype vibration and acoustic motion sensors using highly over-coupled couplers (HOCC). A HOCC fabricated with equal power in both arms after 550 optical power transfer cycles and when illuminated with a light source of 15 {mu}W at a wavelength of 850 nm, this device has a sensitivity of 0.9 {mu}W/{mu}m. A prototype of an optical fiber vibration sensor was made by clamping the 550 cycled HOCC to a cantilever stage to which a vibration source was attached. The maximum linear range of this particular prototype is 12 {mu}m. We have also demonstrated a HOCC having 2150 cycles at 850 nm which has a sensitivity of 4 {mu}W/{mu}m. A HOCC sensor has the possible advantages of high resolution, low cost, and all fiber structure. {copyright} {ital 1996 American Institute of Physics.}

  11. High power windows for WR650 waveguide couplers

    SciTech Connect

    Mircea Stirbet; Robert Rimmer; Thomas Elliott; Edward Daly; Katherine Wilson; Lynn Vogel; Haipeng Wang; Brian Carpenter; Karl Smith; Thomas Powers; Michael Drury; Robert Nichols; G. Davis

    2007-06-01

    Based on the robust, pre-stressed planar window concept successfully tested for PEP II and LEDA, a new design for planar ceramic windows to be used with WR650 waveguide fundamental power couplers at 1300 MHz or 1500 MHz has been developed. These windows should operate in pulsed or CW mode and sustain at least 100 kW average power levels. This paper describes an overview of the simulations performed to match the ceramics in WR650 waveguides, design details, as well as the RF measurements and performance assessed by RF power tests on several high power windows manufactured at JLAB. Funding Agency: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177, and by The Office of Naval Research under contract to the Dept. of Energy.

  12. Misalignment tolerant efficient inverse taper coupler for silicon waveguide

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Michael, Aron; Kwok, Chee Yee; Chen, Ssu-Han

    2015-12-01

    This paper describes an efficient fiber to submicron silicon waveguide coupling based on an inversely tapered silicon waveguide embedded in a SiO2 waveguide that is suspended in air. The inverse taper waveguide consist of a 50um long and 240nm thick silicon that linearly taper in width from 500nm to 120nm, which is embedded in SiO2. The SiO2 waveguide is 6um wide and 10um long. The simulation results show that the coupling loss of this new approach is 2.7dB including the interface loss at the input and output. The tolerance to fiber misalignment at the input of the coupler is 2um in both horizontal and vertical directions for only 1.5dB additional loss.

  13. Novel optical directional coupler based on surface plasmon polaritons

    NASA Astrophysics Data System (ADS)

    Zhao, Huawei; Guang, Xu Guang; Huang, Jingtang

    2008-09-01

    In this paper, finite difference time domain (FDTD) method and perfect matching layer (PML) absorbing boundary condition are adopted to simulate and analyze a novel optical directional coupler (ODC) based on surface plasmon polaritons (SPPs). Transmittance at each output port of the novel ODC with different coupling region lengths shows it follows the general regulations of a conventional ODC. Especially, its transverse size is of nanoscale. The extreme power position offset between the two output ports is proved to be connected with the real part of Ag's complex refractive index. The excess loss and isolation of the ODC are, respectively, 0.57 and 25.9 dB for 1550 nm telecommunication wavelength, when the length of the coupling region equals half of its coupling length.

  14. Element for use in an inductive coupler for downhole components

    DOEpatents

    Hall, David R.; Fox, Joe

    2009-03-31

    An element for use in an inductive coupler for downhole components comprises an annular housing having a generally circular recess. The element further comprises a plurality of generally linear, magnetically conductive segments. Each segment includes a bottom portion, an inner wall portion, and an outer wall portion. The portions together define a generally linear trough from a first end to a second end of each segment. The segments are arranged adjacent to each other within the housing recess to form a generally circular trough. The ends of at least half of the segments are shaped such that the first end of one of the segments is complementary in form to the second end of an adjacent segment. In one embodiment, all of the ends are angled. Preferably, the first ends are angled with the same angle and the second ends are angled with the complementary angle.

  15. Seeing in parallel

    SciTech Connect

    Little, J.J.; Poggio, T.; Gamble, E.B. Jr.

    1988-01-01

    Computer algorithms have been developed for early vision processes that give separate cues to the distance from the viewer of three-dimensional surfaces, their shape, and their material properties. The MIT Vision Machine is a computer system that integrates several early vision modules to achieve high-performance recognition and navigation in unstructured environments. It is also an experimental environment for theoretical progress in early vision algorithms, their parallel implementation, and their integration. The Vision Machine consists of a movable, two-camera Eye-Head input device and an 8K Connection Machine. The authors have developed and implemented several parallel early vision algorithms that compute edge detection, stereopsis, motion, texture, and surface color in close to real time. The integration stage, based on coupled Markov random field models, leads to a cartoon-like map of the discontinuities in the scene, with partial labeling of the brightness edges in terms of their physical origin.

  16. High Performance Computing CFRD -- Final Technial Report

    SciTech Connect

    Hope Forsmann; Kurt Hamman

    2003-01-01

    The Bechtel Waste Treatment Project (WTP), located in Richland, WA, is comprised of many processes containing complex physics. Accurate analyses of the underlying physics of these processes is needed to reduce the amount of added costs during and after construction that are due to unknown process behavior. The WTP will have tight operating margins in order to complete the treatment of the waste on schedule. The combination of tight operating constraints coupled with complex physical processes requires analysis methods that are more accurate than traditional approaches. This study is focused specifically on multidimensional computer aided solutions. There are many skills and tools required to solve engineering problems. Many physical processes are governed by nonlinear partial differential equations. These governing equations have few, if any, closed form solutions. Past and present solution methods require assumptions to reduce these equations to solvable forms. Computational methods take the governing equations and solve them directly on a computational grid. This ability to approach the equations in their exact form reduces the number of assumptions that must be made. This approach increases the accuracy of the solution and its applicability to the problem at hand. Recent advances in computer technology have allowed computer simulations to become an essential tool for problem solving. In order to perform computer simulations as quickly and accurately as possible, both hardware and software must be evaluated. With regards to hardware, the average consumer personal computers (PCs) are not configured for optimal scientific use. Only a few vendors create high performance computers to satisfy engineering needs. Software must be optimized for quick and accurate execution. Operating systems must utilize the hardware efficiently while supplying the software with seamless access to the computer’s resources. From the perspective of Bechtel Corporation and the Idaho

  17. Modulation instability in a triangular three-core coupler with a negative-index material channel

    NASA Astrophysics Data System (ADS)

    Shafeeque Ali, A. K.; Nithyanandan, K.; Porsezian, K.; Maimistov, Andrei I.

    2016-03-01

    A theoretical investigation of the modulation instability (MI) in the three core triangular oppositely directed coupler with negative index material channel is presented. This class of couplers have an effective feedback mechanism due to the opposite directionality of the phase velocities in the negative and positive index channels. It is found that the MI in the nonlinear three core triangular oppositely directed coupler is significantly influenced by the ratio of the forward- to backward-propagating wave power and nonlinearity. Also, in the case of the normal dispersion regime a threshold-like behavior is observed, whereas this behavior is not identified in the anomalous dispersion regime. For the asymmetric case (h\

  18. Applications of fiber optic couplers to diagnostic experiments at the Nevada Test Site

    SciTech Connect

    Whitcomb, B.M.; Smiley, V.N.; Flurer, R.F.; Colburn, C.W.

    1985-01-01

    Fused biconical tapered (FBT) fiber optics star couplers have been used in a variety of applications at the Nevada Test Site to provide increased signal dynamic range for recording devices. Problems which were observed resulted primarily from the modal selection processes which occur in FBT couplers. This paper describes the results of work performed to characterize a new type of splitter for the same applications. The new splitters, obtained commercially, were manufactured using reflection techniques rather than the FBT approach. The splitters exhibit virtually none of the modal problems inherent in the FBT couplers.

  19. Experimental Realization of Two Decoupled Directional Couplers in a Subwavelength Packing by Adiabatic Elimination.

    PubMed

    Mrejen, Michael; Suchowski, Haim; Hatakeyama, Taiki; Wang, Yuan; Zhang, Xiang

    2015-11-11

    On-chip optical data processing and photonic quantum integrated circuits require the integration of densely packed directional couplers at the nanoscale. However, the inherent evanescent coupling at this length scale severely limits the compactness of such on-chip photonic circuits. Here, inspired by the adiabatic elimination in a N-level atomic system, we report an experimental realization of a pair of directional couplers that are effectively isolated from each other despite their subwavelength packing. This approach opens the way to ultradense arrays of waveguide couplers for integrated optical and quantum logic gates. PMID:26421374

  20. Long-range plasmonic directional coupler switches controlled by nematic liquid crystals.

    PubMed

    Zografopoulos, D C; Beccherelli, R

    2013-04-01

    A liquid-crystal tunable plasmonic optical switch based on a long-range metal stripe directional coupler is proposed and theoretically investigated. Extensive electro-optic tuning of the coupler's characteristics is demonstrated by introducing a nematic liquid crystal layer above two coplanar plasmonic waveguides. The switching properties of the proposed plasmonic structure are investigated through rigorous liquid-crystal studies coupled with a finite-element based analysis of light propagation. A directional coupler optical switch is demonstrated, which combines very low power consumption, low operation voltages, adjustable crosstalk and coupling lengths, along with sufficiently reduced insertion losses. PMID:23571914

  1. Simulation of TunneLadder Traveling-Wave Tube Input/Output Coupler Characteristics Using MAFIA

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.; Qureshi, A. Haq

    1996-01-01

    RF input/output coupler characteristics for the TunneLadder traveling-wave tube have been calculated using the three-dimensional computer code, MAFIA and compared to experimental data with good agreement. Theory behind coupling of the TunneLadder interaction circuit to input and output waveguides is presented and VSWR data is calculated for variations on principal coupler dimensions to provide insight into manufacturing tolerances necessary for acceptable performance. Accuracy of results using MAFIA demonstrates how experimental hardware testing of three-dimensional coupler designs can be reduced.

  2. Multi-coupler side-pumped Yb-doped double-clad fiber laser

    NASA Astrophysics Data System (ADS)

    Ou, Pan; Yan, Ping; Gong, Mali; Wei, Wenlou

    2004-05-01

    The side-coupler of angle polished method, using angle-polished multimode fiber and optical adhesive, is used to efficiently pump an Yb-doped double-clad fiber laser. The maximum coupling efficiency of 78.6% is achieved by the side-coupler for a multimode fiber with a circular core of 200 um and a double-clad fiber with a 350/400 um D-shaped inner cladding. While laser diodes (LDs) with three side-couplers are simultaneously used as pump sources, maximum output power of 1.38 W and slope efficiency of 48.9% are demonstrated in the fiber laser system.

  3. High performance computations using dynamical nucleation theory

    SciTech Connect

    Windus, Theresa L.; Kathmann, Shawn M.; Crosby, Lonnie D.

    2008-07-14

    Chemists continue to explore the use of very large computations to perform simulations that describe the molecular level physics of critical challenges in science. In this paper, the Dynamical Nucleation Theory Monte Carlo (DNTMC) model - a model for determining molecular scale nucleation rate constants - and its parallel capabilities are described. The potential for bottlenecks and the challenges to running on future petascale or larger resources are delineated. A "master-slave" solution is proposed to scale to the petascale and will be developed in the NWChem software. In addition, mathematical and data analysis challenges are also described. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Chemical Sciences program. The Pacific Northwest National Laboratory is operated by Battelle for DOE.

  4. High performance vapour-cell frequency standards

    NASA Astrophysics Data System (ADS)

    Gharavipour, M.; Affolderbach, C.; Kang, S.; Bandi, T.; Gruet, F.; Pellaton, M.; Mileti, G.

    2016-06-01

    We report our investigations on a compact high-performance rubidium (Rb) vapour-cell clock based on microwave-optical double-resonance (DR). These studies are done in both DR continuous-wave (CW) and Ramsey schemes using the same Physics Package (PP), with the same Rb vapour cell and a magnetron-type cavity with only 45 cm3 external volume. In the CW-DR scheme, we demonstrate a DR signal with a contrast of 26% and a linewidth of 334 Hz; in Ramsey-DR mode Ramsey signals with higher contrast up to 35% and a linewidth of 160 Hz have been demonstrated. Short-term stabilities of 1.4×10-13 τ-1/2 and 2.4×10-13 τ-1/2 are measured for CW-DR and Ramsey-DR schemes, respectively. In the Ramsey-DR operation, thanks to the separation of light and microwave interactions in time, the light-shift effect has been suppressed which allows improving the long-term clock stability as compared to CW-DR operation. Implementations in miniature atomic clocks are considered.

  5. High performance hand-held gas chromatograph

    SciTech Connect

    Yu, C.M.

    1998-04-28

    The Microtechnology Center of Lawrence Livermore National Laboratory has developed a high performance hand-held, real time detection gas chromatograph (HHGC) by Micro-Electro-Mechanical-System (MEMS) technology. The total weight of this hand-held gas chromatograph is about five lbs., with a physical size of 8{close_quotes} x 5{close_quotes} x 3{close_quotes} including carrier gas and battery. It consumes about 12 watts of electrical power with a response time on the order of one to two minutes. This HHGC has an average effective theoretical plate of about 40k. Presently, its sensitivity is limited by its thermal sensitive detector at PPM. Like a conventional G.C., this HHGC consists mainly of three major components: (1) the sample injector, (2) the column, and (3) the detector with related electronics. The present HHGC injector is a modified version of the conventional injector. Its separation column is fabricated completely on silicon wafers by means of MEMS technology. This separation column has a circular cross section with a diameter of 100 pm. The detector developed for this hand-held GC is a thermal conductivity detector fabricated on a silicon nitride window by MEMS technology. A normal Wheatstone bridge is used. The signal is fed into a PC and displayed through LabView software.

  6. High Performance Graphene Oxide Based Rubber Composites

    NASA Astrophysics Data System (ADS)

    Mao, Yingyan; Wen, Shipeng; Chen, Yulong; Zhang, Fazhong; Panine, Pierre; Chan, Tung W.; Zhang, Liqun; Liang, Yongri; Liu, Li

    2013-08-01

    In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications.

  7. A high performance thin film thermoelectric cooler

    SciTech Connect

    Rowe, D.M.; Min, G.; Volklein, F.

    1998-07-01

    Thin film thermoelectric devices with small dimensions have been fabricated using microelectronics technology and operated successfully in the Seebeck mode as sensors or generators. However, they do not operate successfully in the Peltier mode as coolers, because of the thermal bypass provided by the relatively thick substrate upon which the thermoelectric device is fabricated. In this paper a processing sequence is described which dramatically reduces this thermal bypass and facilitates the fabrication of high performance integrated thin film thermoelectric coolers. In the processing sequence a very thin amorphous SiC (or SiO{sub 2}SiN{sub 4}) film is deposited on a silicon substrate using conventional thin film deposition and a membrane formed by removing the silicon substrate over a desired region using chemical etching or micro-machining. Thermoelements are deposited on the membrane using conventional thin film deposition and patterning techniques and configured so that the region which is to be cooled is abutted to the cold junctions of the Peltier thermoelements while the hot junctions are located at the outer peripheral area which rests on the silicon substrate rim. Heat is pumped laterally from the cooled region to the silicon substrate rim and then dissipated vertically through it to an external heat sink. Theoretical calculations of the performance of a cooler described above indicate that a maximum temperature difference of about 40--50K can be achieved with a maximum heat pumping capacity of around 10 milliwatts.

  8. An integrated high performance Fastbus slave interface

    SciTech Connect

    Christiansen, J.; Ljuslin, C. )

    1993-08-01

    A high performance CMOS Fastbus slave interface ASIC (Application Specific Integrated Circuit) supporting all addressing and data transfer modes defined in the IEEE 960 - 1986 standard is presented. The FAstbus Slave Integrated Circuit (FASIC) is an interface between the asynchronous Fastbus and a clock synchronous processor/memory bus. It can work stand-alone or together with a 32 bit microprocessor. The FASIC is a programmable device enabling its direct use in many different applications. A set of programmable address mapping windows can map Fastbus addresses to convenient memory addresses and at the same time act as address decoding logic. Data rates of 100 MBytes/sec to Fastbus can be obtained using an internal FIFO in the FASIC to buffer data between the two buses during block transfers. Message passing from Fastbus to a microprocessor on the slave module is supported. A compact (70 mm x 170 mm) Fastbus slave piggy back sub-card interface including level conversion between ECL and TTL signal levels has been implemented using surface mount components and the 208 pin FASIC chip.

  9. USING MULTITAIL NETWORKS IN HIGH PERFORMANCE CLUSTERS

    SciTech Connect

    S. COLL; E. FRACHTEMBERG; F. PETRINI; A. HOISIE; L. GURVITS

    2001-03-01

    Using multiple independent networks (also known as rails) is an emerging technique to overcome bandwidth limitations and enhance fault-tolerance of current high-performance clusters. We present and analyze various venues for exploiting multiple rails. Different rail access policies are presented and compared, including static and dynamic allocation schemes. An analytical lower bound on the number of networks required for static rail allocation is shown. We also present an extensive experimental comparison of the behavior of various allocation schemes in terms of bandwidth and latency. Striping messages over multiple rails can substantially reduce network latency, depending on average message size, network load and allocation scheme. The methods compared include a static rail allocation, a round-robin rail allocation, a dynamic allocation based on local knowledge, and a rail allocation that reserves both end-points of a message before sending it. The latter is shown to perform better than other methods at higher loads: up to 49% better than local-knowledge allocation and 37% better than the round-robin allocation. This allocation scheme also shows lower latency and it saturates on higher loads (for messages large enough). Most importantly, this proposed allocation scheme scales well with the number of rails and message sizes.

  10. High Performance Graphene Oxide Based Rubber Composites

    PubMed Central

    Mao, Yingyan; Wen, Shipeng; Chen, Yulong; Zhang, Fazhong; Panine, Pierre; Chan, Tung W.; Zhang, Liqun; Liang, Yongri; Liu, Li

    2013-01-01

    In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications. PMID:23974435

  11. High performance composites with active stiffness control.

    PubMed

    Tridech, Charnwit; Maples, Henry A; Robinson, Paul; Bismarck, Alexander

    2013-09-25

    High performance carbon fiber reinforced composites with controllable stiffness could revolutionize the use of composite materials in structural applications. Here we describe a structural material, which has a stiffness that can be actively controlled on demand. Such a material could have applications in morphing wings or deployable structures. A carbon fiber reinforced-epoxy composite is described that can undergo an 88% reduction in flexural stiffness at elevated temperatures and fully recover when cooled, with no discernible damage or loss in properties. Once the stiffness has been reduced, the required deformations can be achieved at much lower actuation forces. For this proof-of-concept study a thin polyacrylamide (PAAm) layer was electrocoated onto carbon fibers that were then embedded into an epoxy matrix via resin infusion. Heating the PAAm coating above its glass transition temperature caused it to soften and allowed the fibers to slide within the matrix. To produce the stiffness change the carbon fibers were used as resistance heating elements by passing a current through them. When the PAAm coating had softened, the ability of the interphase to transfer load to the fibers was significantly reduced, greatly lowering the flexural stiffness of the composite. By changing the moisture content in PAAm fiber coating, the temperature at which the PAAm softens and the composites undergo a reduction in stiffness can be tuned. PMID:23978266

  12. Low-Cost High-Performance MRI.

    PubMed

    Sarracanie, Mathieu; LaPierre, Cristen D; Salameh, Najat; Waddington, David E J; Witzel, Thomas; Rosen, Matthew S

    2015-01-01

    Magnetic Resonance Imaging (MRI) is unparalleled in its ability to visualize anatomical structure and function non-invasively with high spatial and temporal resolution. Yet to overcome the low sensitivity inherent in inductive detection of weakly polarized nuclear spins, the vast majority of clinical MRI scanners employ superconducting magnets producing very high magnetic fields. Commonly found at 1.5-3 tesla (T), these powerful magnets are massive and have very strict infrastructure demands that preclude operation in many environments. MRI scanners are costly to purchase, site, and maintain, with the purchase price approaching $1 M per tesla (T) of magnetic field. We present here a remarkably simple, non-cryogenic approach to high-performance human MRI at ultra-low magnetic field, whereby modern under-sampling strategies are combined with fully-refocused dynamic spin control using steady-state free precession techniques. At 6.5 mT (more than 450 times lower than clinical MRI scanners) we demonstrate (2.5 × 3.5 × 8.5) mm(3) imaging resolution in the living human brain using a simple, open-geometry electromagnet, with 3D image acquisition over the entire brain in 6 minutes. We contend that these practical ultra-low magnetic field implementations of MRI (<10 mT) will complement traditional MRI, providing clinically relevant images and setting new standards for affordable (<$50,000) and robust portable devices. PMID:26469756

  13. High performance techniques for space mission scheduling

    NASA Technical Reports Server (NTRS)

    Smith, Stephen F.

    1994-01-01

    In this paper, we summarize current research at Carnegie Mellon University aimed at development of high performance techniques and tools for space mission scheduling. Similar to prior research in opportunistic scheduling, our approach assumes the use of dynamic analysis of problem constraints as a basis for heuristic focusing of problem solving search. This methodology, however, is grounded in representational assumptions more akin to those adopted in recent temporal planning research, and in a problem solving framework which similarly emphasizes constraint posting in an explicitly maintained solution constraint network. These more general representational assumptions are necessitated by the predominance of state-dependent constraints in space mission planning domains, and the consequent need to integrate resource allocation and plan synthesis processes. First, we review the space mission problems we have considered to date and indicate the results obtained in these application domains. Next, we summarize recent work in constraint posting scheduling procedures, which offer the promise of better future solutions to this class of problems.

  14. High-performance computers for unmanned vehicles

    NASA Astrophysics Data System (ADS)

    Toms, David; Ettinger, Gil J.

    2005-10-01

    The present trend of increasing functionality onboard unmanned vehicles is made possible by rapid advances in high-performance computers (HPCs). An HPC is characterized by very high computational capability (100s of billions of operations per second) contained in lightweight, rugged, low-power packages. HPCs are critical to the processing of sensor data onboard these vehicles. Operations such as radar image formation, target tracking, target recognition, signal intelligence signature collection and analysis, electro-optic image compression, and onboard data exploitation are provided by these machines. The net effect of an HPC is to minimize communication bandwidth requirements and maximize mission flexibility. This paper focuses on new and emerging technologies in the HPC market. Emerging capabilities include new lightweight, low-power computing systems: multi-mission computing (using a common computer to support several sensors); onboard data exploitation; and large image data storage capacities. These new capabilities will enable an entirely new generation of deployed capabilities at reduced cost. New software tools and architectures available to unmanned vehicle developers will enable them to rapidly develop optimum solutions with maximum productivity and return on investment. These new technologies effectively open the trade space for unmanned vehicle designers.

  15. The design of high-performance gliders

    NASA Technical Reports Server (NTRS)

    Mueller, B.; Heuermann, V.

    1985-01-01

    A high-performance glider is defined as a glider which has been designed to carry the pilot in a minimum of time a given distance, taking into account conditions which are as conveniently as possible. The present investigation has the objective to show approaches for enhancing the cross-country flight cruising speed, giving attention to the difficulties which the design engineer will have to overcome. The characteristics of the cross-country flight and their relation to the cruising speed are discussed, and a description is provided of mathematical expressions concerning the cruising speed, the sinking speed, and the optimum gliding speed. The effect of aspect ratio and wing loading on the cruising speed is illustrated with the aid of a graph. Trends in glider development are explored, taking into consideration the design of laminar profiles, the reduction of profile-related drag by plain flaps, and the variation of wing loading during the flight. A number of suggestions are made for obtaining gliders with improved performance.

  16. Low-Cost High-Performance MRI

    PubMed Central

    Sarracanie, Mathieu; LaPierre, Cristen D.; Salameh, Najat; Waddington, David E. J.; Witzel, Thomas; Rosen, Matthew S.

    2015-01-01

    Magnetic Resonance Imaging (MRI) is unparalleled in its ability to visualize anatomical structure and function non-invasively with high spatial and temporal resolution. Yet to overcome the low sensitivity inherent in inductive detection of weakly polarized nuclear spins, the vast majority of clinical MRI scanners employ superconducting magnets producing very high magnetic fields. Commonly found at 1.5–3 tesla (T), these powerful magnets are massive and have very strict infrastructure demands that preclude operation in many environments. MRI scanners are costly to purchase, site, and maintain, with the purchase price approaching $1 M per tesla (T) of magnetic field. We present here a remarkably simple, non-cryogenic approach to high-performance human MRI at ultra-low magnetic field, whereby modern under-sampling strategies are combined with fully-refocused dynamic spin control using steady-state free precession techniques. At 6.5 mT (more than 450 times lower than clinical MRI scanners) we demonstrate (2.5 × 3.5 × 8.5) mm3 imaging resolution in the living human brain using a simple, open-geometry electromagnet, with 3D image acquisition over the entire brain in 6 minutes. We contend that these practical ultra-low magnetic field implementations of MRI (<10 mT) will complement traditional MRI, providing clinically relevant images and setting new standards for affordable (<$50,000) and robust portable devices. PMID:26469756

  17. Low-Cost High-Performance MRI

    NASA Astrophysics Data System (ADS)

    Sarracanie, Mathieu; Lapierre, Cristen D.; Salameh, Najat; Waddington, David E. J.; Witzel, Thomas; Rosen, Matthew S.

    2015-10-01

    Magnetic Resonance Imaging (MRI) is unparalleled in its ability to visualize anatomical structure and function non-invasively with high spatial and temporal resolution. Yet to overcome the low sensitivity inherent in inductive detection of weakly polarized nuclear spins, the vast majority of clinical MRI scanners employ superconducting magnets producing very high magnetic fields. Commonly found at 1.5-3 tesla (T), these powerful magnets are massive and have very strict infrastructure demands that preclude operation in many environments. MRI scanners are costly to purchase, site, and maintain, with the purchase price approaching $1 M per tesla (T) of magnetic field. We present here a remarkably simple, non-cryogenic approach to high-performance human MRI at ultra-low magnetic field, whereby modern under-sampling strategies are combined with fully-refocused dynamic spin control using steady-state free precession techniques. At 6.5 mT (more than 450 times lower than clinical MRI scanners) we demonstrate (2.5 × 3.5 × 8.5) mm3 imaging resolution in the living human brain using a simple, open-geometry electromagnet, with 3D image acquisition over the entire brain in 6 minutes. We contend that these practical ultra-low magnetic field implementations of MRI (<10 mT) will complement traditional MRI, providing clinically relevant images and setting new standards for affordable (<$50,000) and robust portable devices.

  18. High Performance Oxides-Based Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Ren, Guangkun; Lan, Jinle; Zeng, Chengcheng; Liu, Yaochun; Zhan, Bin; Butt, Sajid; Lin, Yuan-Hua; Nan, Ce-Wen

    2015-01-01

    Thermoelectric materials have attracted much attention due to their applications in waste-heat recovery, power generation, and solid state cooling. In comparison with thermoelectric alloys, oxide semiconductors, which are thermally and chemically stable in air at high temperature, are regarded as the candidates for high-temperature thermoelectric applications. However, their figure-of-merit ZT value has remained low, around 0.1-0.4 for more than 20 years. The poor performance in oxides is ascribed to the low electrical conductivity and high thermal conductivity. Since the electrical transport properties in these thermoelectric oxides are strongly correlated, it is difficult to improve both the thermoelectric power and electrical conductivity simultaneously by conventional methods. This review summarizes recent progresses on high-performance oxide-based thermoelectric bulk-materials including n-type ZnO, SrTiO3, and In2O3, and p-type Ca3Co4O9, BiCuSeO, and NiO, enhanced by heavy-element doping, band engineering and nanostructuring.

  19. A parallel coupled oceanic-atmospheric general circulation model

    SciTech Connect

    Wehner, M.F.; Bourgeois, A.J.; Eltgroth, P.G.; Duffy, P.B.; Dannevik, W.P.

    1994-12-01

    The Climate Systems Modeling group at LLNL has developed a portable coupled oceanic-atmospheric general circulation model suitable for use on a variety of massively parallel (MPP) computers of the multiple instruction, multiple data (MIMD) class. The model is composed of parallel versions of the UCLA atmospheric general circulation model, the GFDL modular ocean model (MOM) and a dynamic sea ice model based on the Hiber formulation extracted from the OPYC ocean model. The strategy to achieve parallelism is twofold. One level of parallelism is accomplished by applying two dimensional domain decomposition techniques to each of the three constituent submodels. A second level of parallelism is attained by a concurrent execution of AGCM and OGCM/sea ice components on separate sets of processors. For this functional decomposition scheme, a flux coupling module has been written to calculate the heat, moisture and momentum fluxes independent of either the AGCM or the OGCM modules. The flux coupler`s other roles are to facilitate the transfer of data between subsystem components and processors via message passing techniques and to interpolate and aggregate between the possibly incommensurate meshes.

  20. Parallel machines: Parallel machine languages

    SciTech Connect

    Iannucci, R.A. )

    1990-01-01

    This book presents a framework for understanding the tradeoffs between the conventional view and the dataflow view with the objective of discovering the critical hardware structures which must be present in any scalable, general-purpose parallel computer to effectively tolerate latency and synchronization costs. The author presents an approach to scalable general purpose parallel computation. Linguistic Concerns, Compiling Issues, Intermediate Language Issues, and hardware/technological constraints are presented as a combined approach to architectural Develoement. This book presents the notion of a parallel machine language.

  1. New architectures to reduce I/O bottlenecks in high-performance systems

    SciTech Connect

    Coleman, S.S.; Watson, R.W.

    1993-01-01

    Large commercial and scientific applications are straining input/output and storage facilities, a condition compounded by new networking and distributed-system technology, and by supercomputer, massively-parallel, and high-performance workstation architectures. This paper reviews large-scale application 1/O requirements that are driving the need for high-performance, distributed, hierarchical storage, and then discusses the emerging shift to network-connected devices and third-party protocol architectures to meet these requirements. It illustrates the discussion with actual implementations and with standards work under way in the IEEE Storage System Standards Working Group.

  2. An Approach to Integrate a Space-Time GIS Data Model with High Performance Computers

    SciTech Connect

    Wang, Dali; Zhao, Ziliang; Shaw, Shih-Lung

    2011-01-01

    In this paper, we describe an approach to integrate a Space-Time GIS data model on a high performance computing platform. The Space-Time GIS data model has been developed on a desktop computing environment. We use the Space-Time GIS data model to generate GIS module, which organizes a series of remote sensing data. We are in the process of porting the GIS module into an HPC environment, in which the GIS modules handle large dataset directly via parallel file system. Although it is an ongoing project, authors hope this effort can inspire further discussions on the integration of GIS on high performance computing platforms.

  3. High-performance laboratories and cleanrooms

    SciTech Connect

    Tschudi, William; Sartor, Dale; Mills, Evan; Xu, Tengfang

    2002-07-01

    The California Energy Commission sponsored this roadmap to guide energy efficiency research and deployment for high performance cleanrooms and laboratories. Industries and institutions utilizing these building types (termed high-tech buildings) have played an important part in the vitality of the California economy. This roadmap's key objective to present a multi-year agenda to prioritize and coordinate research efforts. It also addresses delivery mechanisms to get the research products into the market. Because of the importance to the California economy, it is appropriate and important for California to take the lead in assessing the energy efficiency research needs, opportunities, and priorities for this market. In addition to the importance to California's economy, energy demand for this market segment is large and growing (estimated at 9400 GWH for 1996, Mills et al. 1996). With their 24hr. continuous operation, high tech facilities are a major contributor to the peak electrical demand. Laboratories and cleanrooms constitute the high tech building market, and although each building type has its unique features, they are similar in that they are extremely energy intensive, involve special environmental considerations, have very high ventilation requirements, and are subject to regulations--primarily safety driven--that tend to have adverse energy implications. High-tech buildings have largely been overlooked in past energy efficiency research. Many industries and institutions utilize laboratories and cleanrooms. As illustrated, there are many industries operating cleanrooms in California. These include semiconductor manufacturing, semiconductor suppliers, pharmaceutical, biotechnology, disk drive manufacturing, flat panel displays, automotive, aerospace, food, hospitals, medical devices, universities, and federal research facilities.

  4. Study of High Performance Coronagraphic Techniques

    NASA Technical Reports Server (NTRS)

    Crane, Phil (Technical Monitor); Tolls, Volker

    2004-01-01

    The goal of the Study of High Performance Coronagraphic Techniques project (called CoronaTech) is: 1) to verify the Labeyrie multi-step speckle reduction method and 2) to develop new techniques to manufacture soft-edge occulter masks preferably with Gaussian absorption profile. In a coronagraph, the light from a bright host star which is centered on the optical axis in the image plane is blocked by an occulter centered on the optical axis while the light from a planet passes the occulter (the planet has a certain minimal distance from the optical axis). Unfortunately, stray light originating in the telescope and subsequent optical elements is not completely blocked causing a so-called speckle pattern in the image plane of the coronagraph limiting the sensitivity of the system. The sensitivity can be increased significantly by reducing the amount of speckle light. The Labeyrie multi-step speckle reduction method implements one (or more) phase correction steps to suppress the unwanted speckle light. In each step, the stray light is rephased and then blocked with an additional occulter which affects the planet light (or other companion) only slightly. Since the suppression is still not complete, a series of steps is required in order to achieve significant suppression. The second part of the project is the development of soft-edge occulters. Simulations have shown that soft-edge occulters show better performance in coronagraphs than hard-edge occulters. In order to utilize the performance gain of soft-edge occulters. fabrication methods have to be developed to manufacture these occulters according to the specification set forth by the sensitivity requirements of the coronagraph.

  5. Design of high performance piezo composites actuators

    NASA Astrophysics Data System (ADS)

    Almajid, Abdulhakim A.

    Design of high performance piezo composites actuators are developed. Functionally Graded Microstructure (FGM) piezoelectric actuators are designed to reduce the stress concentration at the middle interface existed in the standard bimorph actuators while maintaining high actuation performance. The FGM piezoelectric laminates are composite materials with electroelastic properties varied through the laminate thickness. The elastic behavior of piezo-laminates actuators is developed using a 2D-elasticity model and a modified classical lamination theory (CLT). The stresses and out-of-plane displacements are obtained for standard and FGM piezoelectric bimorph plates under cylindrical bending generated by an electric field throughout the thickness of the laminate. The analytical model is developed for two different actuator geometries, a rectangular plate actuator and a disk shape actuator. The limitations of CLT are investigated against the 2D-elasticity model for the rectangular plate geometry. The analytical models based on CLT (rectangular and circular) and 2D-elasticity are compared with a model based on Finite Element Method (FEM). The experimental study consists of two FGM actuator systems, the PZT/PZT FGM system and the porous FGM system. The electroelastic properties of each layer in the FGM systems were measured and input in the analytical models to predict the FGM actuator performance. The performance of the FGM actuator is optimized by manipulating the thickness of each layer in the FGM system. The thickness of each layer in the FGM system is made to vary in a linear or non-linear manner to achieve the best performance of the FGM piezoelectric actuator. The analytical and FEM results are found to agree well with the experimental measurements for both rectangular and disk actuators. CLT solutions are found to coincide well with the elasticity solutions for high aspect ratios while the CLT solutions gave poor results compared to the 2D elasticity solutions for

  6. Experience with high-performance PACS

    NASA Astrophysics Data System (ADS)

    Wilson, Dennis L.; Goldburgh, Mitchell M.; Head, Calvin

    1997-05-01

    Lockheed Martin (Loral) has installed PACS with associated teleradiology in several tens of hospitals. The PACS that have been installed have been the basis for a shift to filmless radiology in many of the hospitals. the basic structure for the PACS and the teleradiology that is being used is outlined. The way that the PACS are being used in the hospitals is instructive. The three most used areas for radiology in the hospital are the wards including the ICU wards, the emergency room, and the orthopedics clinic. The examinations are mostly CR images with 20 percent to 30 percent of the examinations being CT, MR, and ultrasound exams. The PACS are being used to realize improved productivity for radiology and for the clinicians. For radiology the same staff is being used for 30 to 50 percent more workload. For the clinicians 10 to 20 percent of their time is being saved in dealing with radiology images. The improved productivity stems from the high performance of the PACS that has been designed and installed. Images are available on any workstation in the hospital within less than two seconds, even during the busiest hour of the day. The examination management functions to restrict the attention of any one user to the examinations that are of interest. The examination management organizes the workflow through the radiology department and the hospital, improving the service of the radiology department by reducing the time until the information from a radiology examination is available. The remaining weak link in the PACS system is transcription. The examination can be acquired, read, an the report dictated in much less than ten minutes. The transcription of the dictated reports can take from a few hours to a few days. The addition of automatic transcription services will remove this weak link.

  7. High-Performance Monopropellants and Catalysts Evaluated

    NASA Technical Reports Server (NTRS)

    Reed, Brian D.

    2004-01-01

    The NASA Glenn Research Center is sponsoring efforts to develop advanced monopropellant technology. The focus has been on monopropellant formulations composed of an aqueous solution of hydroxylammonium nitrate (HAN) and a fuel component. HAN-based monopropellants do not have a toxic vapor and do not need the extraordinary procedures for storage, handling, and disposal required of hydrazine (N2H4). Generically, HAN-based monopropellants are denser and have lower freezing points than N2H4. The performance of HAN-based monopropellants depends on the selection of fuel, the HAN-to-fuel ratio, and the amount of water in the formulation. HAN-based monopropellants are not seen as a replacement for N2H4 per se, but rather as a propulsion option in their own right. For example, HAN-based monopropellants would prove beneficial to the orbit insertion of small, power-limited satellites because of this propellant's high performance (reduced system mass), high density (reduced system volume), and low freezing point (elimination of tank and line heaters). Under a Glenn-contracted effort, Aerojet Redmond Rocket Center conducted testing to provide the foundation for the development of monopropellant thrusters with an I(sub sp) goal of 250 sec. A modular, workhorse reactor (representative of a 1-lbf thruster) was used to evaluate HAN formulations with catalyst materials. Stoichiometric, oxygen-rich, and fuelrich formulations of HAN-methanol and HAN-tris(aminoethyl)amine trinitrate were tested to investigate the effects of stoichiometry on combustion behavior. Aerojet found that fuelrich formulations degrade the catalyst and reactor faster than oxygen-rich and stoichiometric formulations do. A HAN-methanol formulation with a theoretical Isp of 269 sec (designated HAN269MEO) was selected as the baseline. With a combustion efficiency of at least 93 percent demonstrated for HAN-based monopropellants, HAN269MEO will meet the I(sub sp) 250 sec goal.

  8. Study of High-Performance Coronagraphic Techniques

    NASA Astrophysics Data System (ADS)

    Tolls, Volker; Aziz, M. J.; Gonsalves, R. A.; Korzennik, S. G.; Labeyrie, A.; Lyon, R. G.; Melnick, G. J.; Somerstein, S.; Vasudevan, G.; Woodruff, R. A.

    2007-05-01

    We will provide a progress report about our study of high-performance coronagraphic techniques. At SAO we have set up a testbed to test coronagraphic masks and to demonstrate Labeyrie's multi-step speckle reduction technique. This technique expands the general concept of a coronagraph by incorporating a speckle corrector (phase or amplitude) and second occulter for speckle light suppression. The testbed consists of a coronagraph with high precision optics (2 inch spherical mirrors with lambda/1000 surface quality), lasers simulating the host star and the planet, and a single Labeyrie correction stage with a MEMS deformable mirror (DM) for the phase correction. The correction function is derived from images taken in- and slightly out-of-focus using phase diversity. The testbed is operational awaiting coronagraphic masks. The testbed control software for operating the CCD camera, the translation stage that moves the camera in- and out-of-focus, the wavefront recovery (phase diversity) module, and DM control is under development. We are also developing coronagraphic masks in collaboration with Harvard University and Lockheed Martin Corp. (LMCO). The development at Harvard utilizes a focused ion beam system to mill masks out of absorber material and the LMCO approach uses patterns of dots to achieve the desired mask performance. We will present results of both investigations including test results from the first generation of LMCO masks obtained with our high-precision mask scanner. This work was supported by NASA through grant NNG04GC57G, through SAO IR&D funding, and by Harvard University through the Research Experience for Undergraduate Program of Harvard's Materials Science and Engineering Center. Central facilities were provided by Harvard's Center for Nanoscale Systems.

  9. Design and characterization of low-loss 2D grating couplers for silicon photonics integrated circuits

    NASA Astrophysics Data System (ADS)

    Lacava, C.; Carrol, L.; Bozzola, A.; Marchetti, R.; Minzioni, P.; Cristiani, I.; Fournier, M.; Bernabe, S.; Gerace, D.; Andreani, L. C.

    2016-03-01

    We present the characterization of Silicon-on-insulator (SOI) photonic-crystal based 2D grating-couplers (2D-GCs) fabricated by CEA-Leti in the frame of the FP7 Fabulous project, which is dedicated to the realization of devices and systems for low-cost and high-performance passives-optical-networks. On the analyzed samples different test structures are present, including 2D-GC connected to another 2D-GC by different waveguides (in a Mach-Zehnder like configuration), and 2D-GC connected to two separate 2D-GCs, so as to allow a complete assessment of different parameters. Measurements were carried out using a tunable laser source operating in the extended telecom bandwidth and a fiber-based polarization controlling system at the input of device-under-test. The measured data yielded an overall fiber-to-fiber loss of 7.5 dB for the structure composed by an input 2D-GC connected to two identical 2D-GCs. This value was obtained at the peak wavelength of the grating, and the 3-dB bandwidth of the 2D-GC was assessed to be 43 nm. Assuming that the waveguide losses are negligible, so as to make a worst-case analysis, the coupling efficiency of the single 2D-GC results to be equal to -3.75 dB, constituting, to the best of our knowledge, the lowest value ever reported for a fully CMOS compatible 2D-GC. It is worth noting that both the obtained values are in good agreement with those expected by the numerical simulations performed using full 3D analysis by Lumerical FDTD-solutions.

  10. High performance amorphous selenium lateral photodetector

    NASA Astrophysics Data System (ADS)

    Abbaszadeh, Shiva; Allec, Nicholas; Karim, Karim S.

    2012-03-01

    Lateral amorphous selenium (a-Se) detectors based on the metal-semiconductor-metal (MSM) device structure have been studied for indirect detector medical imaging applications. These detectors have raised interest due to their simple structure, ease of fabrication, high-speed, low dark current, low capacitance per unit area and better light utilization. The lateral device structure has a benefit that the electrode spacing may be easily controlled to reduce the required bias for a given desired electric field. In indirect conversion x-ray imaging, the scintillator is coupled to the top of the a-Se MSM photodetector, which itself is integrated on top of the thin-film-transistor (TFT) array. The carriers generated at the top surface of the a-Se layer experience a field that is parallel to the surface, and does not initially sweep them away from the surface. Therefore these carriers may recombine or get trapped in surface states and change the field at the surface, which may degrade the performance of the photodetector. In addition, due to the finite width of the electrodes, the fill factor of the device is less than unity. In this study we examine the effect of lateral drift of carriers and the fill factor on the photodetector performance. The impact of field magnitude on the performance is also investigated.

  11. High performance fuel element with end seal

    DOEpatents

    Lee, Gary E.; Zogg, Gordon J.

    1987-01-01

    A nuclear fuel element comprising an elongate block of refractory material having a generally regular polygonal cross section. The block includes parallel, spaced, first and second end surfaces. The first end surface has a peripheral sealing flange formed thereon while the second end surface has a peripheral sealing recess sized to receive the flange. A plurality of longitudinal first coolant passages are positioned inwardly of the flange and recess. Elongate fuel holes are separate from the coolant passages and disposed inwardly of the flange and the recess. The block is further provided with a plurality of peripheral second coolant passages in general alignment with the flange and the recess for flowing coolant. The block also includes two bypasses for each second passage. One bypass intersects the second passage adjacent to but spaced from the first end surface and intersects a first passage, while the other bypass intersects the second passage adjacent to but spaced from the second end surface and intersects a first passage so that coolant flowing through the second passages enters and exits the block through the associated first passages.

  12. Monolithically integrated asymmetric graded and step-index couplers for microphotonic waveguides

    NASA Astrophysics Data System (ADS)

    Delâge, A.; Janz, S.; Lamontagne, B.; Bogdanov, A.; Dalacu, D.; Xu, D.-X.; Yap, K. P.

    2006-01-01

    A monolithically integrated asymmetric graded index (GRIN) or step-index (GRIN) mode converters for microphotonic waveguides are proposed and described. The design parameters and tolerances are calculated for amorphous silicon (a-Si) couplers integrated with silicon-on-insulator waveguides. The GRIN and step-index couplers operate over a wide wavelength range with low polarization dependence, and the lithographic resolution needed is only +/-1 μm. Finally, experimental results are presented for a single layer 3 μm thick step-index a-Si coupler integrated on a 0.8 μm thick SOI waveguide. The measured variation of coupling efficiency with coupler length is in agreement with theory, with an optimal coupling length of 15 μm for this device.

  13. Experience with the Vibrant Soundbridge RW-Coupler for round window Vibroplasty with tympanosclerosis.

    PubMed

    Iwasaki, Satoshi; Suzuki, Hiroaki; Moteki, Hideaki; Miyagawa, Maiko; Takumi, Yutaka; Usami, Shin-Ichi

    2012-06-01

    Abstract Usage of the Vibrant Soundbridge (VSB) with round window (RW)-Coupler placement at the RW has been shown to successfully treat mixed hearing loss. Coupling between the VSB's floating mass transducer (FMT) and the RW membrane is difficult in the case of sclerosis in the RW and drilling down the bony lip until the RW membrane can be seen completely can possibly induce a perilymphatic fistula. A 68-year-old woman who had bilateral mixed hearing loss with sclerosis in the RW due to tympanosclerosis underwent a RW-Vibroplasty with a RW-Coupler. Speech discrimination scores in quiet and noise and functional gain with the VSB with RW-Coupler were better than those using a conventional hearing aid. The results of the present case have shown the feasibility of implanting a VSB with RW-Coupler in patients with mixed hearing loss due to tympanosclerosis. PMID:22385350

  14. Numerical simulations of input and output couplers for linear accelerator structures

    SciTech Connect

    Ng, C.K.; Ko, K.

    1993-04-01

    We present the numerical procedures involved in the design of coupler cavities for accelerator sections for linear colliders. The MAFIA code is used to simulate an X-band accelerator section with a symmetrical double-input coupler at each end. The transmission properties of the structure are calculated in the time domain and the dimensions of the coupler cavities are adjusted until the power coupling is optimized and frequency synchronism is obtained. We compare the performance of the symmetrical double-input design with that of the conventional single-input type by evaluating the field amplitude and phase asymmetries. We also evaluate the peak gradient in the coupler and discuss the implication of pulse rise time on dark current generation.

  15. Large-Area Binary Blazed Grating Coupler between Nanophotonic Waveguide and LED

    PubMed Central

    Zhou, Wenqian; Zhang, Meiling; Liu, Yu; Zhang, Cheng; Li, Enbang; Miao, Changyun; Tang, Chunxiao

    2014-01-01

    A large-area binary blazed grating coupler for the arrayed waveguide grating (AWG) demodulation integrated microsystem on silicon-on-insulator (SOI) was designed for the first time. Through the coupler, light can be coupled into the SOI waveguide from the InP-based C-band LED for the AWG demodulation integrated microsystem to function. Both the length and width of the grating coupler are 360 μm, as large as the InP-based C-band LED light emitting area in the system. The coupler was designed and optimized based on the finite difference time domain method. When the incident angle of the light source is 0°, the coupling efficiency of the binary blazed grating is 40.92%, and the 3 dB bandwidth is 72 nm at a wavelength of 1550 nm. PMID:25126602

  16. Expanded-mode semiconductor laser with tapered-rib adiabatic-following fiber coupler

    SciTech Connect

    Vawter, G.A.; Smith, R.E.; Hou, H.; Wendt, J.R.

    1997-02-01

    A new diode laser using a Tapered-Rib Adiabatic-Following Fiber Coupler to achieve 2D mode expansion and narrow, symmetric far-field emission without epitaxial regrowth or sharply-defined tips on tapered waveguides is presented.

  17. Fast surrogate-assisted simulation-driven optimization of compact microwave hybrid couplers

    NASA Astrophysics Data System (ADS)

    Kurgan, Piotr; Koziel, Slawomir

    2016-07-01

    This work presents a robust methodology for expedited simulation-driven design optimization of compact microwave hybrid couplers. The technique relies on problem decomposition, and a bottom-up design strategy, starting from the level of basic building blocks of the coupler, and finishing with a tuning procedure that exploits a fast surrogate model of the entire structure. The latter is constructed by cascading local response surface approximations of coupler elementary elements. The cross-coupling effects within the structure are neglected in the first stage of the design process; however, they are accounted for in the tuning phase by means of space-mapping correction of the surrogate. The proposed approach is demonstrated through the design of a compact rat-race and two branch-line couplers. In all cases, the computational cost of the optimization process is very low and corresponds to just a few high-fidelity electromagnetic simulations of respective structures. Experimental validation is also provided.

  18. Fiber pigtailed thin wall capillary coupler for excitation of microsphere WGM resonator.

    PubMed

    Wang, Hanzheng; Lan, Xinwei; Huang, Jie; Yuan, Lei; Kim, Cheol-Woon; Xiao, Hai

    2013-07-01

    In this paper, we demonstrate a fiber pigtailed thin wall capillary coupler for excitation of Whispering Gallery Modes (WGMs) of microsphere resonators. The coupler is made by fusion-splicing an optical fiber with a capillary tube and consequently etching the capillary wall to a thickness of a few microns. Light is coupled through the peripheral contact between inserted microsphere and the etched capillary wall. The coupling efficiency as a function of the wall thickness was studied experimentally. WGM resonance with a Q-factor of 1.14 × 10(4) was observed using a borosilicate glass microsphere with a diameter of 71 μm. The coupler operates in the reflection mode and provides a robust mechanical support to the microsphere resonator. It is expected that the new coupler may find broad applications in sensors, optical filters and lasers. PMID:23842369

  19. Single-Mode Fiber-Optic Directional Couplers For Narrow Spectral Linewidth Analyser

    NASA Astrophysics Data System (ADS)

    Belovolov, , M. I.; Dianov, E. M.; Krjukov, A. P.; Pencheva, V. H.

    1988-02-01

    A new design of Y-type end-fused single-mode fiber directional couplers has been suggest ed, and its optimum parameters with which it is possible to obtain losses of 0,5-1 dB have been determined. Cross-talk attenuation between reverse channels exceeds 60 dB. It has been found by experiments that transmission coefficients of the developed couplers are stable at wavelength variations. Furthermore, Y-type directional couplers maintain polarization state of the propagating radiation. Simple Michelson interferometer based on Y-type fiber optic directional couplers with a new optical fringe visibility registration system for the narrow linewidth( ▵V) = 10 kHz - 1 MHz) analysis of the single-frequency lasers has been created.

  20. A high-performance, portable implementation of the MPI message passing interface standard.

    SciTech Connect

    Gropp, W.; Lusk, E.; Doss, N.; Skjellum, A.; Mathematics and Computer Science; Mississippi State Univ.

    1996-09-01

    MPI (Message Passing Interface) is a specification for a standard library for message passing that was defined by the MPI Forum, a broadly based group of parallel computer vendors, library writers, and applications specialists. Multiple implementations of MPI have been developed. In this paper, we describe MPICH, unique among existing implementations in its design goal of combining portability with high performance. We document its portability and performance and describe the architecture by which these features are simultaneously achieved. We also discuss the set of tools that accompany the free distribution of MPICH, which constitute the beginnings of a portable parallel programming environment. A project of this scope inevitably imparts lessons about parallel computing, the specification being followed, the current hardware and software environment for parallel computing, and project management; we describe those we have learned. Finally, we discuss future developments for MPICH, including those necessary to accommodate extensions to the MPI Standard now being contemplated by the MPI Forum.

  1. Design Procedure and Fabrication of Reproducible Silicon Vernier Devices for High-Performance Refractive Index Sensing

    PubMed Central

    Troia, Benedetto; Khokhar, Ali Z.; Nedeljkovic, Milos; Reynolds, Scott A.; Hu, Youfang; Mashanovich, Goran Z.; Passaro, Vittorio M. N.

    2015-01-01

    In this paper, we propose a generalized procedure for the design of integrated Vernier devices for high performance chemical and biochemical sensing. In particular, we demonstrate the accurate control of the most critical design and fabrication parameters of silicon-on-insulator cascade-coupled racetrack resonators operating in the second regime of the Vernier effect, around 1.55 μm. The experimental implementation of our design strategies has allowed a rigorous and reliable investigation of the influence of racetrack resonator and directional coupler dimensions as well as of waveguide process variability on the operation of Vernier devices. Figures of merit of our Vernier architectures have been measured experimentally, evidencing a high reproducibility and a very good agreement with the theoretical predictions, as also confirmed by relative errors even lower than 1%. Finally, a Vernier gain as high as 30.3, average insertion loss of 2.1 dB and extinction ratio up to 30 dB have been achieved. PMID:26067193

  2. Design Procedure and Fabrication of Reproducible Silicon Vernier Devices for High-Performance Refractive Index Sensing.

    PubMed

    Troia, Benedetto; Khokhar, Ali Z; Nedeljkovic, Milos; Reynolds, Scott A; Hu, Youfang; Mashanovich, Goran Z; Passaro, Vittorio M N

    2015-01-01

    In this paper, we propose a generalized procedure for the design of integrated Vernier devices for high performance chemical and biochemical sensing. In particular, we demonstrate the accurate control of the most critical design and fabrication parameters of silicon-on-insulator cascade-coupled racetrack resonators operating in the second regime of the Vernier effect, around 1.55 μm. The experimental implementation of our design strategies has allowed a rigorous and reliable investigation of the influence of racetrack resonator and directional coupler dimensions as well as of waveguide process variability on the operation of Vernier devices. Figures of merit of our Vernier architectures have been measured experimentally, evidencing a high reproducibility and a very good agreement with the theoretical predictions, as also confirmed by relative errors even lower than 1%. Finally, a Vernier gain as high as 30.3, average insertion loss of 2.1 dB and extinction ratio up to 30 dB have been achieved. PMID:26067193

  3. High power input coupler development for BEPCII 500 MHz superconducting cavity

    NASA Astrophysics Data System (ADS)

    Huang, Tongming; Pan, Weimin; Ma, Qiang; Wang, Guangwei; Dai, Xuwen; Zhang, Zhanjun; Furuya, T.; Mitsunobu, S.

    2010-11-01

    A high power input coupler for a 500 MHz superconducting cavity (SCC) of the upgrade project of Beijing Electron Positron Collider (BEPCII) has been developed in China. Several prototypes have been fabricated and tested successfully. A maximum of 420 kW continuous wave (CW) RF power in traveling wave (TW) mode was achieved in the high power test. The detailed design, fabrication and test of the coupler are described in this paper.

  4. Wet-chemical fabrication of a single leakage-channel grating coupler

    NASA Astrophysics Data System (ADS)

    Weisenbach, Lori; Zelinski, Brian J. J.; Roncone, Ronald L.; Burke, James J.

    1995-04-01

    We demonstrate the fabrication of a unique optical device, the single leakage-channel grating coupler, using sol-gel techniques. Design specifications are outlined to establish the material criteria for the sol-gel compositions. Material choice and preparation are described. We evaluate the characteristics and performance of the single leakage-channel grating coupler by comparing the predicted and the measured branching ratios. The branching ratio of the solution-derived device is within 3% of the theoretically predicted value.

  5. A Novel Multimode Waveguide Coupler for Accurate Power Measurement of Traveling Wave Tube Harmonic Frequencies

    NASA Technical Reports Server (NTRS)

    Wintucky, Edwin G.; Simons, Rainee N.

    2014-01-01

    This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from two dissimilar waveguides is capable of isolating the power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT). In addition to accurate power measurements at harmonic frequencies, a potential application of the MDC is in the design of a beacon source for atmospheric propagation studies at millimeter-wave frequencies.

  6. Direct observation of Landau-Zener tunneling in a curved optical waveguide coupler

    SciTech Connect

    Dreisow, F.; Szameit, A.; Heinrich, M.; Nolte, S.; Tuennermann, A.; Ornigotti, M.; Longhi, S.

    2009-05-15

    An electromagnetic realization of Landau-Zener (LZ) tunneling is experimentally demonstrated in femtosecond-laser written waveguide couplers with a cubically bent axis. Quantitative measurements of light evolution inside the coupler, based on fluorescence imaging, enable to trace the detailed dynamics of the LZ process. The experimental results are in good agreement with the theoretical LZ model for linear crossing of energy levels with constant coupling of finite duration.

  7. Terahertz intracavity generation from output coupler consisting of stacked GaP plates

    NASA Astrophysics Data System (ADS)

    Zhao, Pu; Ragam, Srinivasa; Ding, Yujie J.; Zotova, Ioulia B.

    2012-07-01

    We demonstrate intracavity terahertz generation from an output coupler of a compact dual-frequency solid state laser. The output coupler consisting of unbonded and stacked GaP plates is used as a second-order nonlinear medium where the difference-frequency generation takes place. When quasi-phase matching is achieved within the alternatively rotated GaP plates, terahertz output power is significantly enhanced compared with that for the corresponding external-cavity configuration.

  8. High Performance Diesel Fueled Cabin Heater

    SciTech Connect

    Butcher, Tom

    2001-08-05

    Recent DOE-OHVT studies show that diesel emissions and fuel consumption can be greatly reduced at truck stops by switching from engine idle to auxiliary-fired heaters. Brookhaven National Laboratory (BNL) has studied high performance diesel burner designs that address the shortcomings of current low fire-rate burners. Initial test results suggest a real opportunity for the development of a truly advanced truck heating system. The BNL approach is to use a low pressure, air-atomized burner derived form burner designs used commonly in gas turbine combustors. This paper reviews the design and test results of the BNL diesel fueled cabin heater. The burner design is covered by U.S. Patent 6,102,687 and was issued to U.S. DOE on August 15, 2000.The development of several novel oil burner applications based on low-pressure air atomization is described. The atomizer used is a pre-filming, air blast nozzle of the type commonly used in gas turbine combustion. The air pressure used can b e as low as 1300 Pa and such pressure can be easily achieved with a fan. Advantages over conventional, pressure-atomized nozzles include ability to operate at low input rates without very small passages and much lower fuel pressure requirements. At very low firing rates the small passage sizes in pressure swirl nozzles lead to poor reliability and this factor has practically constrained these burners to firing rates over 14 kW. Air atomization can be used very effectively at low firing rates to overcome this concern. However, many air atomizer designs require pressures that can be achieved only with a compressor, greatly complicating the burner package and increasing cost. The work described in this paper has been aimed at the practical adaptation of low-pressure air atomization to low input oil burners. The objective of this work is the development of burners that can achieve the benefits of air atomization with air pressures practically achievable with a simple burner fan.

  9. High Performance Commercial Fenestration Framing Systems

    SciTech Connect

    Mike Manteghi; Sneh Kumar; Joshua Early; Bhaskar Adusumalli

    2010-01-31

    A major objective of the U.S. Department of Energy is to have a zero energy commercial building by the year 2025. Windows have a major influence on the energy performance of the building envelope as they control over 55% of building energy load, and represent one important area where technologies can be developed to save energy. Aluminum framing systems are used in over 80% of commercial fenestration products (i.e. windows, curtain walls, store fronts, etc.). Aluminum framing systems are often required in commercial buildings because of their inherent good structural properties and long service life, which is required from commercial and architectural frames. At the same time, they are lightweight and durable, requiring very little maintenance, and offer design flexibility. An additional benefit of aluminum framing systems is their relatively low cost and easy manufacturability. Aluminum, being an easily recyclable material, also offers sustainable features. However, from energy efficiency point of view, aluminum frames have lower thermal performance due to the very high thermal conductivity of aluminum. Fenestration systems constructed of aluminum alloys therefore have lower performance in terms of being effective barrier to energy transfer (heat loss or gain). Despite the lower energy performance, aluminum is the choice material for commercial framing systems and dominates the commercial/architectural fenestration market because of the reasons mentioned above. In addition, there is no other cost effective and energy efficient replacement material available to take place of aluminum in the commercial/architectural market. Hence it is imperative to improve the performance of aluminum framing system to improve the energy performance of commercial fenestration system and in turn reduce the energy consumption of commercial building and achieve zero energy building by 2025. The objective of this project was to develop high performance, energy efficient commercial

  10. High Efficiency, High Performance Clothes Dryer

    SciTech Connect

    Peter Pescatore; Phil Carbone

    2005-03-31

    This program covered the development of two separate products; an electric heat pump clothes dryer and a modulating gas dryer. These development efforts were independent of one another and are presented in this report in two separate volumes. Volume 1 details the Heat Pump Dryer Development while Volume 2 details the Modulating Gas Dryer Development. In both product development efforts, the intent was to develop high efficiency, high performance designs that would be attractive to US consumers. Working with Whirlpool Corporation as our commercial partner, TIAX applied this approach of satisfying consumer needs throughout the Product Development Process for both dryer designs. Heat pump clothes dryers have been in existence for years, especially in Europe, but have not been able to penetrate the market. This has been especially true in the US market where no volume production heat pump dryers are available. The issue has typically been around two key areas: cost and performance. Cost is a given in that a heat pump clothes dryer has numerous additional components associated with it. While heat pump dryers have been able to achieve significant energy savings compared to standard electric resistance dryers (over 50% in some cases), designs to date have been hampered by excessively long dry times, a major market driver in the US. The development work done on the heat pump dryer over the course of this program led to a demonstration dryer that delivered the following performance characteristics: (1) 40-50% energy savings on large loads with 35 F lower fabric temperatures and similar dry times; (2) 10-30 F reduction in fabric temperature for delicate loads with up to 50% energy savings and 30-40% time savings; (3) Improved fabric temperature uniformity; and (4) Robust performance across a range of vent restrictions. For the gas dryer development, the concept developed was one of modulating the gas flow to the dryer throughout the dry cycle. Through heat modulation in a

  11. Integrating advanced facades into high performance buildings

    SciTech Connect

    Selkowitz, Stephen E.

    2001-05-01

    Glass is a remarkable material but its functionality is significantly enhanced when it is processed or altered to provide added intrinsic capabilities. The overall performance of glass elements in a building can be further enhanced when they are designed to be part of a complete facade system. Finally the facade system delivers the greatest performance to the building owner and occupants when it becomes an essential element of a fully integrated building design. This presentation examines the growing interest in incorporating advanced glazing elements into more comprehensive facade and building systems in a manner that increases comfort, productivity and amenity for occupants, reduces operating costs for building owners, and contributes to improving the health of the planet by reducing overall energy use and negative environmental impacts. We explore the role of glazing systems in dynamic and responsive facades that provide the following functionality: Enhanced sun protection and cooling load control while improving thermal comfort and providing most of the light needed with daylighting; Enhanced air quality and reduced cooling loads using natural ventilation schemes employing the facade as an active air control element; Reduced operating costs by minimizing lighting, cooling and heating energy use by optimizing the daylighting-thermal tradeoffs; Net positive contributions to the energy balance of the building using integrated photovoltaic systems; Improved indoor environments leading to enhanced occupant health, comfort and performance. In addressing these issues facade system solutions must, of course, respect the constraints of latitude, location, solar orientation, acoustics, earthquake and fire safety, etc. Since climate and occupant needs are dynamic variables, in a high performance building the facade solution have the capacity to respond and adapt to these variable exterior conditions and to changing occupant needs. This responsive performance capability

  12. High performance simulation of environmental tracers in heterogeneous domains.

    PubMed

    Gardner, William P; Hammond, Glenn; Lichtner, Peter

    2015-04-01

    In this study, we use PFLOTRAN, a highly scalable, parallel, flow, and reactive transport code to simulate the concentrations of 3H, 3He, CFC-11, CFC-12, CFC-113, SF6, 39Ar, and the mean groundwater age in heterogeneous fields on grids with an excess of 10 million nodes. We utilize this computational platform to simulate the concentration of multiple tracers in high-resolution, heterogeneous 2D and 3D domains, and calculate tracer-derived ages. Tracer-derived ages show systematic biases toward younger ages when the groundwater age distribution contains water older than the maximum tracer age. The deviation of the tracer-derived age distribution from the true groundwater age distribution increases with increasing heterogeneity of the system. However, the effect of heterogeneity is diminished as the mean travel time gets closer to the tracer age limit. Age distributions in 3D domains differ significantly from 2D domains. 3D simulations show decreased mean age, and less variance in age distribution for identical heterogeneity statistics. High-performance computing allows for investigation of tracer and groundwater age systematics in high-resolution domains, providing a platform for understanding and utilizing environmental tracer and groundwater age information in heterogeneous 3D systems. PMID:24372403

  13. Scout: high-performance heterogeneous computing made simple

    SciTech Connect

    Jablin, James; Mc Cormick, Patrick; Herlihy, Maurice

    2011-01-26

    Researchers must often write their own simulation and analysis software. During this process they simultaneously confront both computational and scientific problems. Current strategies for aiding the generation of performance-oriented programs do not abstract the software development from the science. Furthermore, the problem is becoming increasingly complex and pressing with the continued development of many-core and heterogeneous (CPU-GPU) architectures. To acbieve high performance, scientists must expertly navigate both software and hardware. Co-design between computer scientists and research scientists can alleviate but not solve this problem. The science community requires better tools for developing, optimizing, and future-proofing codes, allowing scientists to focus on their research while still achieving high computational performance. Scout is a parallel programming language and extensible compiler framework targeting heterogeneous architectures. It provides the abstraction required to buffer scientists from the constantly-shifting details of hardware while still realizing higb-performance by encapsulating software and hardware optimization within a compiler framework.

  14. Optimizing high performance computing workflow for protein functional annotation.

    PubMed

    Stanberry, Larissa; Rekepalli, Bhanu; Liu, Yuan; Giblock, Paul; Higdon, Roger; Montague, Elizabeth; Broomall, William; Kolker, Natali; Kolker, Eugene

    2014-09-10

    Functional annotation of newly sequenced genomes is one of the major challenges in modern biology. With modern sequencing technologies, the protein sequence universe is rapidly expanding. Newly sequenced bacterial genomes alone contain over 7.5 million proteins. The rate of data generation has far surpassed that of protein annotation. The volume of protein data makes manual curation infeasible, whereas a high compute cost limits the utility of existing automated approaches. In this work, we present an improved and optmized automated workflow to enable large-scale protein annotation. The workflow uses high performance computing architectures and a low complexity classification algorithm to assign proteins into existing clusters of orthologous groups of proteins. On the basis of the Position-Specific Iterative Basic Local Alignment Search Tool the algorithm ensures at least 80% specificity and sensitivity of the resulting classifications. The workflow utilizes highly scalable parallel applications for classification and sequence alignment. Using Extreme Science and Engineering Discovery Environment supercomputers, the workflow processed 1,200,000 newly sequenced bacterial proteins. With the rapid expansion of the protein sequence universe, the proposed workflow will enable scientists to annotate big genome data. PMID:25313296

  15. Multimethod communication for high-performance metacomputing applications

    SciTech Connect

    Foster, I.; Geisler, J.; Tuecke, S.; Kesselman, C.

    1996-12-31

    Metacomputing systems use high-speed networks to connect supercomputers, mass storage systems, scientific instruments, and display devices with the objective of enabling parallel applications to access geographically distributed computing resources. However, experience shows that high performance often can be achieved only if applications can integrate diverse communication substrates, transport mechanisms, and protocols, chosen according to where communication is directed, what is communicated, or when communication is performed. In this article, we describe a software architecture that addresses this requirement. This architecture allows multiple communication methods to be supported transparently in a single application, with either automatic or user-specified selection criteria guiding the methods used for each communication. We describe an implementation of this architecture, based on the Nexus communication library, and use this implementation to evaluate performance issues. The implementation supported a wide variety of applications in the I-WAY metacomputing experiment at Supercomputing 95; we use one of these applications to provide a quantitative demonstration of the advantages of multimethod communication in a heterogeneous networked environment.

  16. High-performance polymeric componentry for telecom and datacom applications

    NASA Astrophysics Data System (ADS)

    Eldada, Louay A.; Blomquist, Robert; Shacklette, Lawrence W.; McFarland, Michael J.

    2000-03-01

    We review a polymeric waveguide technology developed to produce affordable high-performance optical components that address the needs of both the telecom and the datacom industries. We engineer advanced organic polymers that can be readily made into planar single-mode, multimode, and micro-optical waveguide structures of controlled numerical apertures and geometries. These materials are formed from highly crosslinked acrylate monomers with specific linkages that determine properties such as flexibility, toughness, optical loss, and environmental stability. These monomers are intermiscible, providing for precise continuous adjustment of the refractive index over a wide range. In polymer form, they exhibit state-of-the-art loss values, suppressed polarization effects, and exceptional stability, enabling their use in a variety of demanding applications. Waveguides are formed photolithographically, with the liquid monomer mixture polymerizing upon illumination in the UV via either mask exposure or laser direct writing. A wide range of rigid and flexible structures can be used. The devices we describe include a variety of passive and thermo-optically active elements that achieve a variety of coupling, routing, and filtering functionalities. These devices can be either individually pigtailed and packaged components or they can be part of a massively parallel photonic integrated circuit on the multichip module, board, or backplane level.

  17. High Performance Simulation of Environmental Tracers in Heterogeneous Formations

    NASA Astrophysics Data System (ADS)

    Gardner, P.; Hammond, G. E.; Lichtner, P. C.; Arnold, B. W.

    2013-12-01

    Environmental tracers provide information on fluid flux, yielding important information for use in groundwater studies. Currently environmental tracer interpretation has been limited by computational expense. Here we use a scalable, massively parallel, flow and reactive transport code PFLOTRAN to simulate the concentrations of 3H, 3He, CFC-11, CFC-12, CFC-113, SF6, 39Ar, 81Kr , 4He and the mean groundwater age in 2D and 3D heterogeneous fields on grids with an excess of 10 million nodes. We utilize this computational platform to simulate the spatial distribution of environmental tracer concentration, tracer derived ages and modeled mean ground water age in heterogeneous aquifers. Modeled concentrations are then used to calculate tracer derived ages. The deviation of the tracer derived age distribution from the true groundwater age distribution increases with increasing heterogeneity of the system. The separation between the apparent age derived from different tracers also increases with increasing system heterogeneity. Age distributions in 3D aquifers differ significantly from 2D simulations with similar spatial statistics. The addition of the 3rd dimension increases connectivity, decreasing mean age and reducing age variability. High performance computation allows for investigation of tracer and groundwater age spatial distribution in unprecedented detail, providing a foundation for the next generation of environmental tracer interpretation.

  18. High Performance Storage System Scalability: Architecture, Implementation, and Experience

    SciTech Connect

    Watson, R W

    2005-01-05

    The High Performance Storage System (HPSS) provides scalable hierarchical storage management (HSM), archive, and file system services. Its design, implementation and current dominant use are focused on HSM and archive services. It is also a general-purpose, global, shared, parallel file system, potentially useful in other application domains. When HPSS design and implementation began over a decade ago, scientific computing power and storage capabilities at a site, such as a DOE national laboratory, was measured in a few 10s of gigaops, data archived in HSMs in a few 10s of terabytes at most, data throughput rates to an HSM in a few megabytes/s, and daily throughput with the HSM in a few gigabytes/day. At that time, the DOE national laboratories and IBM HPSS design team recognized that we were headed for a data storage explosion driven by computing power rising to teraops/petaops requiring data stored in HSMs to rise to petabytes and beyond, data transfer rates with the HSM to rise to gigabytes/s and higher, and daily throughput with a HSM in 10s of terabytes/day. This paper discusses HPSS architectural, implementation and deployment experiences that contributed to its success in meeting the above orders of magnitude scaling targets. We also discuss areas that need additional attention as we continue significant scaling into the future.

  19. The design of linear algebra libraries for high performance computers

    SciTech Connect

    Dongarra, J.J. |; Walker, D.W.

    1993-08-01

    This paper discusses the design of linear algebra libraries for high performance computers. Particular emphasis is placed on the development of scalable algorithms for MIMD distributed memory concurrent computers. A brief description of the EISPACK, LINPACK, and LAPACK libraries is given, followed by an outline of ScaLAPACK, which is a distributed memory version of LAPACK currently under development. The importance of block-partitioned algorithms in reducing the frequency of data movement between different levels of hierarchical memory is stressed. The use of such algorithms helps reduce the message startup costs on distributed memory concurrent computers. Other key ideas in our approach are the use of distributed versions of the Level 3 Basic Linear Algebra Subprograms (BLAS) as computational building blocks, and the use of Basic Linear Algebra Communication Subprograms (BLACS) as communication building blocks. Together the distributed BLAS and the BLACS can be used to construct higher-level algorithms, and hide many details of the parallelism from the application developer. The block-cyclic data distribution is described, and adopted as a good way of distributing block-partitioned matrices. Block-partitioned versions of the Cholesky and LU factorizations are presented, and optimization issues associated with the implementation of the LU factorization algorithm on distributed memory concurrent computers are discussed, together with its performance on the Intel Delta system. Finally, approaches to the design of library interfaces are reviewed.

  20. High-performance reconfigurable hardware architecture for restricted Boltzmann machines.

    PubMed

    Ly, Daniel Le; Chow, Paul

    2010-11-01

    Despite the popularity and success of neural networks in research, the number of resulting commercial or industrial applications has been limited. A primary cause for this lack of adoption is that neural networks are usually implemented as software running on general-purpose processors. Hence, a hardware implementation that can exploit the inherent parallelism in neural networks is desired. This paper investigates how the restricted Boltzmann machine (RBM), which is a popular type of neural network, can be mapped to a high-performance hardware architecture on field-programmable gate array (FPGA) platforms. The proposed modular framework is designed to reduce the time complexity of the computations through heavily customized hardware engines. A method to partition large RBMs into smaller congruent components is also presented, allowing the distribution of one RBM across multiple FPGA resources. The framework is tested on a platform of four Xilinx Virtex II-Pro XC2VP70 FPGAs running at 100 MHz through a variety of different configurations. The maximum performance was obtained by instantiating an RBM of 256 × 256 nodes distributed across four FPGAs, which resulted in a computational speed of 3.13 billion connection-updates-per-second and a speedup of 145-fold over an optimized C program running on a 2.8-GHz Intel processor. PMID:20858578

  1. High Performance GPU-Based Fourier Volume Rendering.

    PubMed

    Abdellah, Marwan; Eldeib, Ayman; Sharawi, Amr

    2015-01-01

    Fourier volume rendering (FVR) is a significant visualization technique that has been used widely in digital radiography. As a result of its (N (2)log⁡N) time complexity, it provides a faster alternative to spatial domain volume rendering algorithms that are (N (3)) computationally complex. Relying on the Fourier projection-slice theorem, this technique operates on the spectral representation of a 3D volume instead of processing its spatial representation to generate attenuation-only projections that look like X-ray radiographs. Due to the rapid evolution of its underlying architecture, the graphics processing unit (GPU) became an attractive competent platform that can deliver giant computational raw power compared to the central processing unit (CPU) on a per-dollar-basis. The introduction of the compute unified device architecture (CUDA) technology enables embarrassingly-parallel algorithms to run efficiently on CUDA-capable GPU architectures. In this work, a high performance GPU-accelerated implementation of the FVR pipeline on CUDA-enabled GPUs is presented. This proposed implementation can achieve a speed-up of 117x compared to a single-threaded hybrid implementation that uses the CPU and GPU together by taking advantage of executing the rendering pipeline entirely on recent GPU architectures. PMID:25866499

  2. The Nanoelectric Modeling Tool (NEMO) and Its Expansion to High Performance Parallel Computing

    NASA Technical Reports Server (NTRS)

    Klimeck, G.; Bowen, C.; Boykin, T.; Oyafuso, F.; Salazar-Lazaro, C.; Stoica, A.; Cwik, T.

    1998-01-01

    Material variations on an atomic scale enable the quantum mechanical functionality of devices such as resonant tunneling diodes (RTDs), quantum well infrared photodetectors (QWIPs), quantum well lasers, and heterostructure field effect transistors (HFETs).

  3. High Performance Data Distribution for Scientific Community

    NASA Astrophysics Data System (ADS)

    Tirado, Juan M.; Higuero, Daniel; Carretero, Jesus

    2010-05-01

    Institutions such as NASA, ESA or JAXA find solutions to distribute data from their missions to the scientific community, and their long term archives. This is a complex problem, as it includes a vast amount of data, several geographically distributed archives, heterogeneous architectures with heterogeneous networks, and users spread around the world. We propose a novel architecture (HIDDRA) that solves this problem aiming to reduce user intervention in data acquisition and processing. HIDDRA is a modular system that provides a highly efficient parallel multiprotocol download engine, using a publish/subscribe policy which helps the final user to obtain data of interest transparently. Our system can deal simultaneously with multiple protocols (HTTP,HTTPS, FTP, GridFTP among others) to obtain the maximum bandwidth, reducing the workload in data server and increasing flexibility. It can also provide high reliability and fault tolerance, as several sources of data can be used to perform one file download. HIDDRA architecture can be arranged into a data distribution network deployed on several sites that can cooperate to provide former features. HIDDRA has been addressed by the 2009 e-IRG Report on Data Management as a promising initiative for data interoperability. Our first prototype has been evaluated in collaboration with the ESAC centre in Villafranca del Castillo (Spain) that shows a high scalability and performance, opening a wide spectrum of opportunities. Some preliminary results have been published in the Journal of Astrophysics and Space Science [1]. [1] D. Higuero, J.M. Tirado, J. Carretero, F. Félix, and A. de La Fuente. HIDDRA: a highly independent data distribution and retrieval architecture for space observation missions. Astrophysics and Space Science, 321(3):169-175, 2009

  4. Parallel pipelining

    SciTech Connect

    Joseph, D.D.; Bai, R.; Liao, T.Y.; Huang, A.; Hu, H.H.

    1995-09-01

    In this paper the authors introduce the idea of parallel pipelining for water lubricated transportation of oil (or other viscous material). A parallel system can have major advantages over a single pipe with respect to the cost of maintenance and continuous operation of the system, to the pressure gradients required to restart a stopped system and to the reduction and even elimination of the fouling of pipe walls in continuous operation. The authors show that the action of capillarity in small pipes is more favorable for restart than in large pipes. In a parallel pipeline system, they estimate the number of small pipes needed to deliver the same oil flux as in one larger pipe as N = (R/r){sup {alpha}}, where r and R are the radii of the small and large pipes, respectively, and {alpha} = 4 or 19/7 when the lubricating water flow is laminar or turbulent.

  5. Comparative study on compact planar waveguide based photonic integrated couplers using simple effective index method

    NASA Astrophysics Data System (ADS)

    Deka, Bidyut; Dutta, Aradhana; Sahu, Partha P.

    2013-11-01

    The miniaturization of photonic components in integrated optic waveguide devices to microscale platform has attracted enormous attention from the researchers and entrepreneurs. In this paper, we present and report a comparative study of photonic integrated planar waveguide based couplers using a mathematical model based on sinusoidal mode simple effective index method (SEIM). The basic photonic integrated components such as directional coupler (DC), two mode interference (TMI) coupler and multimode interference (MMI) coupler have been designed and fabricated using the versatile SiON waveguide technology (SiON as the waveguide core material using silica waveguide). The experimental results have been compared with the SEIM based theoretical results and further verified with the commercially available software tool based on beam propagation method (BPM). With a focus towards device compactness, particular emphasis is placed on device geometry in an endeavour to achieve the same. In this direction, the theoretical and experimental results obtained have been compared with tooth shaped grating assisted geometry for these photonic components. It is found that the grating assisted structures have the beat length ~0.5 times lower than that of the conventional geometry. Further it is seen that the beat length of TMI coupler is smaller compared to the DC and MMI coupler.

  6. Analysis of a single ring resonator with 2×2 90-degree multimode waveguide turning couplers

    NASA Astrophysics Data System (ADS)

    Chiu, C. L.; Liao, Yen-Hsun

    2016-02-01

    A novel design of a single ring resonator with two low-loss 2×2 90-degree multimode waveguide turning mirror couplers based on a InP structure. The coupling factor of the 2×2 90-degree multimode waveguide turning mirror coupler is inversed for K=0.85 to K=0.15 when one folding is achieved. The 2×2 90-degree turning mirror coupler for K=0.15 is (3/4)Lπ in length. Its length is reduced 3 times than the conventional straight 2×2 multimode waveguide interference coupler (9/4)Lπ in length for K=0.15. The cavity length of the curve waveguide (90-degree arc length) in this ring resonator with two 2×2 90-degree multimode waveguide turning couplers is decreased 1/2 times than with two 2×2 MMI couplers (180-degree arc length). The free spectral range (FSR) is increased 2 times. The output spectral response gets a FSR of 82 GHz for the device and a contrast of 4 dB and FWHM of 0.24 nm for the drop port. The results of numerical analysis calculated by the transfer functions in a single ring resonator are agreement with the experimental results.

  7. Optical performance study of duplex Y-branch coupler with different structures

    NASA Astrophysics Data System (ADS)

    Huang, Kuang-Lung; Liu, Te-Shu; Ding, Jei; Chen, Jin-Jia

    2014-11-01

    As the increase of environment and conservation consciousness in recent years, green-lighting concept begins attracting much attention of the people in our country; particularly, the exploration of daylight lighting system is an obvious example. However, in this nature-light lighting system, versatile optical couplers are required to guide and dissipate sunlight into different indoor spaces to produce assistant illumination, and their coupling efficiencies directly affect the whole efficiency of the lighting system. Thus, they play an important role in the daylight lighting system. To obtain high efficient optical couplers, this thesis, other than investigating various used Y-branch couplers, proposes another new type of coupler, which has a positive- or negative-arc Y-branch structure to split a light-beam into two beams or to combine two light-beams into one beam with high efficient light output. From optical simulation results, it can be seen that the output efficiency of this symmetrical Y-branch coupler with positive or negative arc can reach above 90%, no matter it is used as a combiner or splitter. Furthermore, this thesis also goes through an investigation of the Y-branch output field distribution and an improved arc design; the coupling efficiency between the coupler and an externally connected optical fiber can be promoted.

  8. Design of coupler for the NSLS-II storage ring superconducting RF cavity

    SciTech Connect

    Yeddulla, M.; Rose, J.

    2011-03-28

    NSLS-II is a 3GeV, 500mA, high brightness, 1 MW beam power synchrotron facility that is designed with four superconducting cavities working at 499.68 MHz. To operate the cavities in over-damped coupling condition, an External Quality Factor (Qext) of {approx}65000 is required. We have modified the existing coupler for the CESR-B cavity which has a Qext of {approx}200,000 to meet the requirements of NSLS-II. CESR-B cavity has an aperture coupler with a coupler 'tongue' connecting the cavity to the waveguide. We have optimized the length, width and thickness of the 'tongue' as well as the width of the aperture to increase the coupling using the three dimensional electromagnetic field solver, HFSS. Several possible designs will be presented. We have modified the coupler of the CESR-B cavity to be used in the storage ring at the NSLS-II project using HFSS and verified using CST Microwave Studio. Using a combination of increasing the length and width of the coupler tongue and increasing the width of the aperture, the external Q of the cavity coupler was decreased to {approx}65000 as required for the design of the NSLS-II storage ring design.

  9. Wakefield and RF Kicks Due to Coupler Asymmetry in TESLA-Type Accelerating Cavities

    SciTech Connect

    Bane, K.L.F.; Adolphsen, C.; Li, Z.; Dohlus, M.; Zagorodnov, I.; Gonin, I.; Lunin, A.; Solyak, N.; Yakovlev, V.; Gjonaj, E.; Weiland, T.; /Darmstadt, Tech. Hochsch.

    2008-07-07

    In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate fields that will kick the beam transversely and degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental (FM) and higher mode (HM) couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetry in) the fundamental RF fields and the other, due to transverse wakefields that are generated by the beam even when it is on axis. In this report we calculate the strength of these kicks and estimate their effect on the ILC beam. The TESLA cavity comprises nine cells, one HM coupler in the upstream end, and one (identical, though rotated) HM coupler and one FM coupler in the downstream end (for their shapes and location see Figs. 1, 2) [1]. The cavity is 1.1 m long, the iris radius 35 mm, and the coupler beam pipe radius 39 mm. Note that the couplers reach closer to the axis than the irises, down to a distance of 30 mm.

  10. Thermal interface pastes nanostructured for high performance

    NASA Astrophysics Data System (ADS)

    Lin, Chuangang

    Thermal interface materials in the form of pastes are needed to improve thermal contacts, such as that between a microprocessor and a heat sink of a computer. High-performance and low-cost thermal pastes have been developed in this dissertation by using polyol esters as the vehicle and various nanoscale solid components. The proportion of a solid component needs to be optimized, as an excessive amount degrades the performance, due to the increase in the bond line thickness. The optimum solid volume fraction tends to be lower when the mating surfaces are smoother, and higher when the thermal conductivity is higher. Both a low bond line thickness and a high thermal conductivity help the performance. When the surfaces are smooth, a low bond line thickness can be even more important than a high thermal conductivity, as shown by the outstanding performance of the nanoclay paste of low thermal conductivity in the smooth case (0.009 mum), with the bond line thickness less than 1 mum, as enabled by low storage modulus G', low loss modulus G" and high tan delta. However, for rough surfaces, the thermal conductivity is important. The rheology affects the bond line thickness, but it does not correlate well with the performance. This study found that the structure of carbon black is an important parameter that governs the effectiveness of a carbon black for use in a thermal paste. By using a carbon black with a lower structure (i.e., a lower DBP value), a thermal paste that is more effective than the previously reported carbon black paste was obtained. Graphite nanoplatelet (GNP) was found to be comparable in effectiveness to carbon black (CB) pastes for rough surfaces, but it is less effective for smooth surfaces. At the same filler volume fraction, GNP gives higher thermal conductivity than carbon black paste. At the same pressure, GNP gives higher bond line thickness than CB (Tokai or Cabot). The effectiveness of GNP is limited, due to the high bond line thickness. A

  11. Data parallelism

    SciTech Connect

    Gorda, B.C.

    1992-09-01

    Data locality is fundamental to performance on distributed memory parallel architectures. Application programmers know this well and go to great pains to arrange data for optimal performance. Data Parallelism, a model from the Single Instruction Multiple Data (SIMD) architecture, is finding a new home on the Multiple Instruction Multiple Data (MIMD) architectures. This style of programming, distinguished by taking the computation to the data, is what programmers have been doing by hand for a long time. Recent work in this area holds the promise of making the programmer's task easier.

  12. Data parallelism

    SciTech Connect

    Gorda, B.C.

    1992-09-01

    Data locality is fundamental to performance on distributed memory parallel architectures. Application programmers know this well and go to great pains to arrange data for optimal performance. Data Parallelism, a model from the Single Instruction Multiple Data (SIMD) architecture, is finding a new home on the Multiple Instruction Multiple Data (MIMD) architectures. This style of programming, distinguished by taking the computation to the data, is what programmers have been doing by hand for a long time. Recent work in this area holds the promise of making the programmer`s task easier.

  13. A Queue Simulation Tool for a High Performance Scientific Computing Center

    NASA Technical Reports Server (NTRS)

    Spear, Carrie; McGalliard, James

    2007-01-01

    The NASA Center for Computational Sciences (NCCS) at the Goddard Space Flight Center provides high performance highly parallel processors, mass storage, and supporting infrastructure to a community of computational Earth and space scientists. Long running (days) and highly parallel (hundreds of CPUs) jobs are common in the workload. NCCS management structures batch queues and allocates resources to optimize system use and prioritize workloads. NCCS technical staff use a locally developed discrete event simulation tool to model the impacts of evolving workloads, potential system upgrades, alternative queue structures and resource allocation policies.

  14. Toward a common component architecture for high-performance scientific computing

    SciTech Connect

    Armstrong, R; Gannon, D; Geist, A; Katarzyna, K; Kohn, S; McInnes, L; Parker, S; Smolinski, B

    1999-06-09

    This paper describes work in progress to develop a standard for interoperability among high-performance scientific components. This research stems from growing recognition that the scientific community must better manage the complexity of multidisciplinary simulations and better address scalable performance issues on parallel and distributed architectures. Driving forces are the need for fast connections among components that perform numerically intensive work and parallel collective interactions among components that use multiple processes or threads. This paper focuses on the areas we believe are most crucial for such interactions, namely an interface definition language that supports scientific abstractions for specifying component interfaces and a ports connection model for specifying component interactions.

  15. The NAS Parallel Benchmarks

    SciTech Connect

    Bailey, David H.

    2009-11-15

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

  16. New NAS Parallel Benchmarks Results

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  17. Application of High-performance Visual Analysis Methods to Laser Wakefield Particle Acceleration Data

    SciTech Connect

    Rubel, Oliver; Prabhat, Mr.; Wu, Kesheng; Childs, Hank; Meredith, Jeremy; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Ahern, Sean; Weber, Gunther H.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes

    2008-08-28

    Our work combines and extends techniques from high-performance scientific data management and visualization to enable scientific researchers to gain insight from extremely large, complex, time-varying laser wakefield particle accelerator simulation data. We extend histogram-based parallel coordinates for use in visual information display as well as an interface for guiding and performing data mining operations, which are based upon multi-dimensional and temporal thresholding and data subsetting operations. To achieve very high performance on parallel computing platforms, we leverage FastBit, a state-of-the-art index/query technology, to accelerate data mining and multi-dimensional histogram computation. We show how these techniques are used in practice by scientific researchers to identify, visualize and analyze a particle beam in a large, time-varying dataset.

  18. High Performance Home Building Guide for Habitat for Humanity Affiliates

    SciTech Connect

    Lindsey Marburger

    2010-10-01

    This guide covers basic principles of high performance Habitat construction, steps to achieving high performance Habitat construction, resources to help improve building practices, materials, etc., and affiliate profiles and recommendations.

  19. HEATR project: ATR algorithm parallelization

    NASA Astrophysics Data System (ADS)

    Deardorf, Catherine E.

    1998-09-01

    High Performance Computing (HPC) Embedded Application for Target Recognition (HEATR) is a project funded by the High Performance Computing Modernization Office through the Common HPC Software Support Initiative (CHSSI). The goal of CHSSI is to produce portable, parallel, multi-purpose, freely distributable, support software to exploit emerging parallel computing technologies and enable application of scalable HPC's for various critical DoD applications. Specifically, the CHSSI goal for HEATR is to provide portable, parallel versions of several existing ATR detection and classification algorithms to the ATR-user community to achieve near real-time capability. The HEATR project will create parallel versions of existing automatic target recognition (ATR) detection and classification algorithms and generate reusable code that will support porting and software development process for ATR HPC software. The HEATR Team has selected detection/classification algorithms from both the model- based and training-based (template-based) arena in order to consider the parallelization requirements for detection/classification algorithms across ATR technology. This would allow the Team to assess the impact that parallelization would have on detection/classification performance across ATR technology. A field demo is included in this project. Finally, any parallel tools produced to support the project will be refined and returned to the ATR user community along with the parallel ATR algorithms. This paper will review: (1) HPCMP structure as it relates to HEATR, (2) Overall structure of the HEATR project, (3) Preliminary results for the first algorithm Alpha Test, (4) CHSSI requirements for HEATR, and (5) Project management issues and lessons learned.

  20. Combining high productivity and high performance in image processing using Single Assignment C

    NASA Astrophysics Data System (ADS)

    Wieser, Volkmar; Moser, Bernhard; Scholz, Sven-Bodo; Herhut, Stephan; Guo, Jing

    2011-07-01

    In this paper the problem of high performance software engineering is addressed in the context of image processing regarding productivity and optimized exploitation of hardware resources. Therefore, we introduce the functional array processing language Single Assignment C (SaC), which relies on a hardware virtualization concept for automated, parallel machine code generation. An illustrative benchmarking example proves both utility and adequacy of SaC for image processing.