Science.gov

Sample records for multistage interconnection networks

  1. Nonuniform traffic spots (NUTS) in multistage interconnection networks

    SciTech Connect

    Lang, T.; Kurisaki, L. . Dept. of Computer Science)

    1990-09-01

    The performance of multistage interconnection networks for multiprocessors is degraded when the traffic pattern produces nonuniform congestion in the blocking switches, that is, when there exist nonuniform traffic spots. For some specific patterns the authors evaluate this degradation in performance and propose modifications to the network organization and operation to reduce the degradation. Successful modifications are the use of diverting switches and the extension of the network with additional links. The use of these modifications makes the network more effective for a larger variety of traffic patterns. The authors also consider the case in which the network carries the superposition of two types of traffic. One type is the high throughput data and instruction traffic, while the other consists of control and I/O packets which are of low throughput but have severe real-time constraints. The authors conclude that diverting switches and networks with additional links are also suitable for assuring low latency for the real-time traffic, especially when using the displacing mode.

  2. Interconnection networks

    DOEpatents

    Faber, V.; Moore, J.W.

    1988-06-20

    A network of interconnected processors is formed from a vertex symmetric graph selected from graphs GAMMA/sub d/(k) with degree d, diameter k, and (d + 1)exclamation/ (d /minus/ k + 1)exclamation processors for each d greater than or equal to k and GAMMA/sub d/(k, /minus/1) with degree d /minus/ 1, diameter k + 1, and (d + 1)exclamation/(d /minus/ k + 1)exclamation processors for each d greater than or equal to k greater than or equal to 4. Each processor has an address formed by one of the permutations from a predetermined sequence of letters chosen a selected number of letters at a time, and an extended address formed by appending to the address the remaining ones of the predetermined sequence of letters. A plurality of transmission channels is provided from each of the processors, where each processor has one less channel than the selected number of letters forming the sequence. Where a network GAMMA/sub d/(k, /minus/1) is provided, no processor has a channel connected to form an edge in a direction delta/sub 1/. Each of the channels has an identification number selected from the sequence of letters and connected from a first processor having a first extended address to a second processor having a second address formed from a second extended address defined by moving to the front of the first extended address the letter found in the position within the first extended address defined by the channel identification number. The second address is then formed by selecting the first elements of the second extended address corresponding to the selected number used to form the address permutations. 9 figs.

  3. Enzyme-regulated the changes of pH values for assembling a colorimetric and multistage interconnection logic network with multiple readouts.

    PubMed

    Huang, Yanyan; Ran, Xiang; Lin, Youhui; Ren, Jinsong; Qu, Xiaogang

    2015-04-22

    Based on enzymatic reactions-triggered changes of pH values and biocomputing, a novel and multistage interconnection biological network with multiple easy-detectable signal outputs has been developed. Compared with traditional chemical computing, the enzyme-based biological system could overcome the interference between reactions or the incompatibility of individual computing gates and offer a unique opportunity to assemble multicomponent/multifunctional logic circuitries. Our system included four enzyme inputs: β-galactosidase (β-gal), glucose oxidase (GOx), esterase (Est) and urease (Ur). With the assistance of two signal transducers (gold nanoparticles and acid-base indicators) or pH meter, the outputs of the biological network could be conveniently read by the naked eyes. In contrast to current methods, the approach present here could realize cost-effective, label-free and colorimetric logic operations without complicated instrument. By designing a series of Boolean logic operations, we could logically make judgment of the compositions of the samples on the basis of visual output signals. Our work offered a promising paradigm for future biological computing technology and might be highly useful in future intelligent diagnostics, prodrug activation, smart drug delivery, process control, and electronic applications. PMID:25819791

  4. CAISSON: Interconnect Network Simulator

    NASA Technical Reports Server (NTRS)

    Springer, Paul L.

    2006-01-01

    Cray response to HPCS initiative. Model future petaflop computer interconnect. Parallel discrete event simulation techniques for large scale network simulation. Built on WarpIV engine. Run on laptop and Altix 3000. Can be sized up to 1000 simulated nodes per host node. Good parallel scaling characteristics. Flexible: multiple injectors, arbitration strategies, queue iterators, network topologies.

  5. Optical Interconnection Networks

    NASA Astrophysics Data System (ADS)

    Bergman, Keren; Hughes, Gary

    2004-07-01

    In current high-performance computing and communications systems an emerging need for ultra-high-capacity, low-latency interconnection networks has led investigators to consider insertion of optical-domain switching fabrics. The use of optical technology for the physical switching layer within data communication systems is clearly advantageous in providing maximum bandwidth per cable particularly through the exploitation of DWDM. Furthermore, the transparency offered in the optical domain allows potentially wide flexibility in the data encoding and protocols. However, many key challenges remain to the successful implementation of optical packet routing, as optical signals cannot be processed efficiently or buffered for an arbitrary time. Clearly, innovative architectures, switching fabrics, and packet processing subsystems that employ optical technologies in synergetic fashions with powerful electronic techniques would be poised to harvest the immense transmission bandwidth of optics creating the ultimate "unlimited-capacity" interconnection network.

  6. Optical Interconnection Networks

    NASA Astrophysics Data System (ADS)

    Bergman, Keren; Hughes, Gary

    2004-05-01

    In current high-performance computing and communications systems an emerging need for ultra-high-capacity, low-latency interconnection networks has led investigators to consider insertion of optical-domain switching fabrics. The use of optical technology for the physical switching layer within data communication systems is clearly advantageous in providing maximum bandwidth per cable particularly through the exploitation of DWDM. Furthermore, the transparency offered in the optical domain allows potentially wide flexibility in the data encoding and protocols. However, many key challenges remain to the successful implementation of optical packet routing, as optical signals cannot be processed efficiently or buffered for an arbitrary time. Clearly, innovative architectures, switching fabrics, and packet processing subsystems that employ optical technologies in synergetic fashions with powerful electronic techniques would be poised to harvest the immense transmission bandwidth of optics creating the ultimate "unlimited-capacity" interconnection network.

  7. Optical Interconnection Networks

    NASA Astrophysics Data System (ADS)

    Bergman, Keren; Hughes, Gary

    2004-06-01

    In current high-performance computing and communications systems an emerging need for ultra-high-capacity, low-latency interconnection networks has led investigators to consider insertion of optical-domain switching fabrics. The use of optical technology for the physical switching layer within data communication systems is clearly advantageous in providing maximum bandwidth per cable particularly through the exploitation of DWDM. Furthermore, the transparency offered in the optical domain allows potentially wide flexibility in the data encoding and protocols. However, many key challenges remain to the successful implementation of optical packet routing, as optical signals cannot be processed efficiently or buffered for an arbitrary time. Clearly, innovative architectures, switching fabrics, and packet processing subsystems that employ optical technologies in synergetic fashions with powerful electronic techniques would be poised to harvest the immense transmission bandwidth of optics creating the ultimate "unlimited-capacity" interconnection network.

  8. Policy issues in interconnecting networks

    NASA Technical Reports Server (NTRS)

    Leiner, Barry M.

    1989-01-01

    To support the activities of the Federal Research Coordinating Committee (FRICC) in creating an interconnected set of networks to serve the research community, two workshops were held to address the technical support of policy issues that arise when interconnecting such networks. The workshops addressed the required and feasible technologies and architectures that could be used to satisfy the desired policies for interconnection. The results of the workshop are documented.

  9. Optimal software multicast in wormhole-routed multistage networks

    SciTech Connect

    Xu, H.; Gui, Y.D.; Ni, L.M.

    1994-12-31

    Multistage interconnection networks are a popular class of interconnection architecture for constructing scalable parallel computers (SPCs). The focus of this paper is on wormhole routed multistage networks supporting turnaround routing. Existing machines characterized by such a system model include the IBM SP-1, TMC CM-5, and Meiko CS-2. Efficient collective communication among processor nodes is critical to the performance of SPCS. A system-level multicast service, in which the same message is delivered from a source node to an arbitrary number of destination nodes, is fundamental in supporting collective communication primitives including the application-level broadcast, reduction, and barrier synchronization. This paper addresses how to efficiently implement multicast services in wormhole routed multistage networks, in the absence of hardware multicast support, by exploiting the properties of the switching technology. An optimal multicast algorithm is proposed. The results of implementations on a 64-node SP-1 show that the proposed algorithm significantly out performs the application-level broadcast primitives provided by currently existing collective communication libraries including the public domain MPI.

  10. Breathing synchronization in interconnected networks

    PubMed Central

    Louzada, V. H. P.; Araújo, N. A. M.; Andrade, J. S.; Herrmann, H. J.

    2013-01-01

    Global synchronization in a complex network of oscillators emerges from the interplay between its topology and the dynamics of the pairwise interactions among its numerous components. When oscillators are spatially separated, however, a time delay appears in the interaction which might obstruct synchronization. Here we study the synchronization properties of interconnected networks of oscillators with a time delay between networks and analyze the dynamics as a function of the couplings and communication lag. We discover a new breathing synchronization regime, where two groups appear in each network synchronized at different frequencies. Each group has a counterpart in the opposite network, one group is in phase and the other in anti-phase with their counterpart. For strong couplings, instead, networks are internally synchronized but a phase shift between them might occur. The implications of our findings on several socio-technical and biological systems are discussed. PMID:24256765

  11. Traffic congestion in interconnected complex networks

    NASA Astrophysics Data System (ADS)

    Tan, Fei; Wu, Jiajing; Xia, Yongxiang; Tse, Chi K.

    2014-06-01

    Traffic congestion in isolated complex networks has been investigated extensively over the last decade. Coupled network models have recently been developed to facilitate further understanding of real complex systems. Analysis of traffic congestion in coupled complex networks, however, is still relatively unexplored. In this paper, we try to explore the effect of interconnections on traffic congestion in interconnected Barabási-Albert scale-free networks. We find that assortative coupling can alleviate traffic congestion more readily than disassortative and random coupling when the node processing capacity is allocated based on node usage probability. Furthermore, the optimal coupling probability can be found for assortative coupling. However, three types of coupling preferences achieve similar traffic performance if all nodes share the same processing capacity. We analyze interconnected Internet autonomous-system-level graphs of South Korea and Japan and obtain similar results. Some practical suggestions are presented to optimize such real-world interconnected networks accordingly.

  12. Survey of fault-tolerant multistage networks and comparison to the extra stage cube

    SciTech Connect

    Adams, G.B. III; Siegel, H.J.

    1984-01-01

    A variety of fault-tolerant multistage interconnection networks for parallel processing systems that have been proposed in the literature are surveyed. A network is fault-tolerant if it can continue to meet its fault tolerance criterion in the presence of one or more failures of the type(s) allowed by its fault model. Significant differences in fault models and fault-tolerance criteria exist among various fault-tolerant networks. This makes direct comparison of these networks difficult. In analyzing the networks, this paper compares the various models and assesses the effect of choosing a common model and criterion. Network characteristics such as degree of fault tolerance, routing control method, and permutation capability are discussed. The networks surveyed and compared to the extra stage cube are the modified baseline, augmented delta, f-network, enhanced inverse augmented data manipulator, gamma, fault-tolerant Benes, and beta-networks. 21 references.

  13. Navigability of interconnected networks under random failures

    PubMed Central

    De Domenico, Manlio; Solé-Ribalta, Albert; Gómez, Sergio; Arenas, Alex

    2014-01-01

    Assessing the navigability of interconnected networks (transporting information, people, or goods) under eventual random failures is of utmost importance to design and protect critical infrastructures. Random walks are a good proxy to determine this navigability, specifically the coverage time of random walks, which is a measure of the dynamical functionality of the network. Here, we introduce the theoretical tools required to describe random walks in interconnected networks accounting for structure and dynamics inherent to real systems. We develop an analytical approach for the covering time of random walks in interconnected networks and compare it with extensive Monte Carlo simulations. Generally speaking, interconnected networks are more resilient to random failures than their individual layers per se, and we are able to quantify this effect. As an application––which we illustrate by considering the public transport of London––we show how the efficiency in exploring the multiplex critically depends on layers’ topology, interconnection strengths, and walk strategy. Our findings are corroborated by data-driven simulations, where the empirical distribution of check-ins and checks-out is considered and passengers travel along fastest paths in a network affected by real disruptions. These findings are fundamental for further development of searching and navigability strategies in real interconnected systems. PMID:24912174

  14. Hierarchical interconnection networks for multicomputer systems

    SciTech Connect

    Dandamudi, S.P. ); Eager, D.L. )

    1990-06-01

    Multicomputer systems are distributed-memory MIMD systems. Communication in these systems occurs through explicit message passing. Therefore, the underlying processor interconnection network plays an important and direct role in determining their performance. Several types f interconnection networks have been proposed. Unfortunately, no network is universally better. Ideally, therefore, systems should use more than one such network. Furthermore, systems that have large numbers of processors should be able to exploit locality in communication in order to obtain improved performance. This paper proposes the use of hierarchical interconnection networks to meet both these requirements. A performance analysis of a class of hierarchical interconnection networks is presented. This analysis includes both static analysis (queuing delays are neglected) and queuing analysis. In both cases, the hierarchical networks are shown to have better cost-benefit ratios. The queuing analysis is also validated (within our model) by several simulation experiments. The impact of two performance enhancement schemes---replication of links and improved routing algorithms---on hierarchical interconnection network performance is also presented.

  15. Random walk centrality in interconnected multilayer networks

    NASA Astrophysics Data System (ADS)

    Solé-Ribalta, Albert; De Domenico, Manlio; Gómez, Sergio; Arenas, Alex

    2016-06-01

    Real-world complex systems exhibit multiple levels of relationships. In many cases they require to be modeled as interconnected multilayer networks, characterizing interactions of several types simultaneously. It is of crucial importance in many fields, from economics to biology and from urban planning to social sciences, to identify the most (or the less) influent nodes in a network using centrality measures. However, defining the centrality of actors in interconnected complex networks is not trivial. In this paper, we rely on the tensorial formalism recently proposed to characterize and investigate this kind of complex topologies, and extend two well known random walk centrality measures, the random walk betweenness and closeness centrality, to interconnected multilayer networks. For each of the measures we provide analytical expressions that completely agree with numerically results.

  16. Nonlinear Dynamics on Interconnected Networks

    NASA Astrophysics Data System (ADS)

    Arenas, Alex; De Domenico, Manlio

    2016-06-01

    Networks of dynamical interacting units can represent many complex systems, from the human brain to transportation systems and societies. The study of these complex networks, when accounting for different types of interactions has become a subject of interest in the last few years, especially because its representational power in the description of users' interactions in diverse online social platforms (Facebook, Twitter, Instagram, etc.) [1], or in representing different transportation modes in urban networks [2,3]. The general name coined for these networks is multilayer networks, where each layer accounts for a type of interaction (see Fig. 1).

  17. Epidemic spread on interconnected metapopulation networks

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Tanaka, Gouhei; Suzuki, Hideyuki; Aihara, Kazuyuki

    2014-09-01

    Numerous real-world networks have been observed to interact with each other, resulting in interconnected networks that exhibit diverse, nontrivial behavior with dynamical processes. Here we investigate epidemic spreading on interconnected networks at the level of metapopulation. Through a mean-field approximation for a metapopulation model, we find that both the interaction network topology and the mobility probabilities between subnetworks jointly influence the epidemic spread. Depending on the interaction between subnetworks, proper controls of mobility can efficiently mitigate epidemics, whereas an extremely biased mobility to one subnetwork will typically cause a severe outbreak and promote the epidemic spreading. Our analysis provides a basic framework for better understanding of epidemic behavior in related transportation systems as well as for better control of epidemics by guiding human mobility patterns.

  18. Epidemic spread on interconnected metapopulation networks.

    PubMed

    Wang, Bing; Tanaka, Gouhei; Suzuki, Hideyuki; Aihara, Kazuyuki

    2014-09-01

    Numerous real-world networks have been observed to interact with each other, resulting in interconnected networks that exhibit diverse, nontrivial behavior with dynamical processes. Here we investigate epidemic spreading on interconnected networks at the level of metapopulation. Through a mean-field approximation for a metapopulation model, we find that both the interaction network topology and the mobility probabilities between subnetworks jointly influence the epidemic spread. Depending on the interaction between subnetworks, proper controls of mobility can efficiently mitigate epidemics, whereas an extremely biased mobility to one subnetwork will typically cause a severe outbreak and promote the epidemic spreading. Our analysis provides a basic framework for better understanding of epidemic behavior in related transportation systems as well as for better control of epidemics by guiding human mobility patterns. PMID:25314481

  19. Ultralight Interconnected Metal Oxide Nanotube Networks.

    PubMed

    Stano, Kelly L; Faraji, Shaghayegh; Hodges, Ryan; Yildiz, Ozkan; Wells, Brian; Akyildiz, Halil I; Zhao, Junjie; Jur, Jesse; Bradford, Philip D

    2016-05-01

    Record-breaking ultralow density aluminum oxide structures are prepared using a novel templating technique. The alumina structures are unique in that they are comprised by highly aligned and interconnected nanotubes yielding anisotropic behavior. Large-scale network structures with complex form-factors can easily be made using this technique. The application of the low density networks as humidity sensing materials as well as thermal insulation is demonstrated. PMID:26969860

  20. Blocking in multirate interconnection networks

    NASA Astrophysics Data System (ADS)

    Valdimarsson, Einir

    1994-02-01

    We present an extension of the classical methods used to evaluate blocking probability. This method is applicable to multirate circuit and fast packet/ATM switching systems. The analytical methods are presented and compared with simulation results using Benes networks as an example. Extensive simulation has been performed focusing on ways to reduce blocking to acceptable levels.

  1. Modeling and synthesis of multicomputer interconnection networks

    NASA Technical Reports Server (NTRS)

    Standley, Hilda M.; Auxter, D. Steve

    1990-01-01

    The type of interconnection network employed has a profound effect on the performance of a multicomputer and multiprocessor design. Adequate models are needed to aid in the design and development of interconnection networks. A novel modeling approach using statistical and optimization techniques is described. This method represents an attempt to compare diverse interconnection network designs in a way that allows not only the best of existing designs to be identified but to suggest other, perhaps hybrid, networks that may offer better performance. Stepwise linear regression is used to develop a polynomial surface representation of performance in a (k+1) space with a total of k quantitative and qualitative independent variables describing graph-theoretic characteristics such as size, average degree, diameter, radius, girth, node-connectivity, edge-connectivity, minimum dominating set size, and maximum number of prime node and edge cutsets. Dependent variables used to measure performance are average message delay and the ratio of message completion rate to network connection cost. Response Surface Methodology (RSM) optimizes a response variable from a polynomial function of several independent variables. Steepest ascent path may also be used to approach optimum points.

  2. Electric network interconnection of Mashreq Arab Countries

    SciTech Connect

    El-Amin, I.M.; Al-Shehri, A.M.; Opoku, G.; Al-Baiyat, S.A.; Zedan, F.M.

    1994-12-01

    Power system interconnection is a well established practice for a variety of technical and economical reasons. Several interconnected networks exist worldwide for a number of factors. Some of these networks cross international boundaries. This presentation discusses the future developments of the power systems of Mashreq Arab Countries (MAC). MAC consists of Bahrain, Egypt, Iraq, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, United Arab Emirates (UAE), and Yemen. Mac power systems are operated by government or semigovernment bodies. Many of these countries have national or regional electric grids but are generally isolated from each other. With the exception of Saudi Arabia power systems, which employ 60 Hz, all other MAC utilities use 50 Hz frequency. Each country is served by one utility, except Saudi Arabia, which is served by four major utilities and some smaller utilities serving remote towns and small load centers. The major utilities are the Saudi Consolidated electric Company in the Eastern Province (SCECO East), SCECO Center, SCECO West, and SCECO South. These are the ones considered in this study. The energy resources in MAC are varied. Countries such as Egypt, Iraq, and Syria have significant hydro resources.The gulf countries and Iraq have abundant fossil fuel, The variation in energy resources as well as the characteristics of the electric load make it essential to look into interconnections beyond the national boundaries. Most of the existing or planned interconnections involve few power systems. A study involving 12 countries and over 20 utilities with different characteristics represents a very large scale undertaking.

  3. Comparison of large guided-wave interconnection networks for optical computation systems

    NASA Astrophysics Data System (ADS)

    Schneider, Eric G.; Michalson, William R.

    1993-07-01

    Seven common interconnection architectures are evaluated for use as guided-wave interconnection networks. Comparisons are based on characteristics such as the number of switching elements, number of stages or path length, number of layers, number of waveguide crossings, connectivity and routing algorithms. Investigation of the active splitter/active combiner, passive splitter/active combiner, crossbar, n-stage, buddy type multistage interconnection network (MIN), duobanyan and Benes architectures reveals a trade space which is both complicated and previously not well explored. Even among the topologically equivalent MINs such as the baseline, reverse baseline, regular SW banyan with S equals F equals 2, indirect binary n-cube, modified data manipulator, omega or flip networks, the number of waveguide crossings varies while other properties remain constant. Analysis of this larger set of factors reveals more complex trade offs, and presents these architectures in a new perspective.

  4. A new class of rearrangeable interconnection networks

    SciTech Connect

    Douglass, B.G.

    1989-01-01

    With the current interest in general purpose multiprocessing systems and distributed processing networks, a need exists for rearrangeable interconnection networks. These networks can simultaneously transmit information from all sources to all destinations, for all possible combinations of destinations. Such networks exist, and among these the Benes network is of asymptotically optimal hardware complexity. However, this network requires excessive time to recompute the switch settings each time a new set of transmissions is requested by the source processors. Some algorithms exist to reduce this time overhead but they require excessive hardware to compute the settings. This thesis introduces a new class of rearrangeable networks, called reduced networks, based on an extension of Clos three-stage networks. It is shown that the switches in the first and third stages of Clos networks can be constructed as unique path logarithmic networks. Only the center-stage switches must be rearrangeable. This fact is then used to develop a compact network structure. The routing properties of this structure are defined, and it is shown that there is a connectivity in the setting of the switches for any Clos network. An upper and lower bound on this connectivity are established, leading to a fast routing algorithm, with a trade off between the routing time and the network hardware complexity. This can be exploited by the network designer to achieve the best combination of hardware cost and data transfer rate for the particular application. For network sizes contemplated within the foreseeable future, the resulting design will in most cases be closer to the ideal combination than any other network.

  5. Towards energy aware optical networks and interconnects

    NASA Astrophysics Data System (ADS)

    Glesk, Ivan; Osadola, Tolulope; Idris, Siti

    2013-10-01

    In a today's world, information technology has been identified as one of the major factors driving economic prosperity. Datacenters businesses have been growing significantly in the past few years. The equipments in these datacenters need to be efficiently connected to each other and also to the outside world in order to enable effective exchange of information. This is why there is need for highly scalable, energy savvy and reliable network connectivity infrastructure that is capable of accommodating the large volume of data being exchanged at any time within the datacenter network and the outside network in general. These devices that can ensure such effective connectivity currently require large amount of energy in order to meet up with these increasing demands. In this paper, an overview of works being done towards realizing energy aware optical networks and interconnects for datacenters is presented. Also an OCDMA approach is discussed as potential multiple access technique for future optical network interconnections. We also presented some challenges that might inhibit effective implementation of the OCDMA multiplexing scheme.

  6. Multistage neural network model for dynamic scene analysis

    SciTech Connect

    Ajjimarangsee, P.

    1989-01-01

    This research is concerned with dynamic scene analysis. The goal of scene analysis is to recognize objects and have a meaningful interpretation of the scene from which images are obtained. The task of the dynamic scene analysis process generally consists of region identification, motion analysis and object recognition. The objective of this research is to develop clustering algorithms using neural network approach and to investigate a multi-stage neural network model for region identification and motion analysis. The research is separated into three parts. First, a clustering algorithm using Kohonens' self-organizing feature map network is developed to be capable of generating continuous membership valued outputs. A newly developed version of the updating algorithm of the network is introduced to achieve a high degree of parallelism. A neural network model for the fuzzy c-means algorithm is proposed. In the second part, the parallel algorithms of a neural network model for clustering using the self-organizing feature maps approach and a neural network that models the fuzzy c-means algorithm are modified for implementation on a distributed memory parallel architecture. In the third part, supervised and unsupervised neural network models for motion analysis are investigated. For a supervised neural network, a three layer perceptron network is trained by a series of images to recognize the movement of the objects. For the unsupervised neural network, a self-organizing feature mapping network will learn to recognize the movement of the objects without an explicit training phase.

  7. Electric currents in networks of interconnected memristors.

    PubMed

    Nedaaee Oskoee, Ehsan; Sahimi, Muhammad

    2011-03-01

    Chua [IEEE Trans. Circuit Theory 1, 507 (1971).] argued that, in addition to the standard resistors, capacitors, and inductors, there must be a fourth fundamental element in electrical circuits, which he called a memory resistor or memristor. Strukov et al. [Nature (London) 453, 80 (2008)] showed how memristive behavior arises in some thin semiconducting films. Unlike other passive elements, however, a memristor with large sizes cannot be fabricated, because scale up of a memristor to dimensions of the order of microns causes loss of the memristive effect by decreasing the width of the doped region relative to the overall size of the memristor. A microscale memristor is, however, essential to most of the potential applications. One way of fabricating such a microscale memristor without losing the memristive effect is to make a network of very small interconnected memristors. We report the results of numerical simulations of electrical currents in such networks of interconnected memristors, as well as memristors and Ohmic conductors. The memristor networks exhibit a rich variety of interesting properties, including weakly and strongly memristive regimes, a possible first-order transition at the connectivity threshold, generation of second harmonics in the strongly memristive regime, and the universal dependence of the network's strength on the frequency. Moreover, we show that the polarity of the memristors can play an important role in the overall properties of the memristor network, in particular its speed of switching, which may have a potentially important application to faster computers. None of these properties are exhibited by linear resistor networks, or even by nonlinear resistor networks without a memory effect. PMID:21517452

  8. Fault-tolerant interconnection network and image-processing applications for the PASM parallel processing system

    SciTech Connect

    Adams, G.B. III

    1984-01-01

    The demand for very high speed data processing coupled with falling hardware costs has made large-scale parallel and distributed computer systems both desirable and feasible. Two modes of parallel processing are single instruction stream-multiple data stream (SIMD) and multiple instruction stream-multiple data stream (MIMD). PASM, a partitionable SIMD/MIMD system, is a reconfigurable multimicroprocessor system being designed for image processing and pattern recognition. An important component of these systems is the interconnection network, the mechanism for communication among the computation nodes and memories. Assuring high reliability for such complex systems is a significant task. Thus, a crucial practical aspect of an interconnection network is fault tolerance. In answer to this need, the Extra Stage Cube (ESC), a fault-tolerant, multistage cube-type interconnection network, is define. The fault tolerance of the ESC is explored for both single and multiple faults, routing tags are defined, and consideration is given to permuting data and partitioning the ESC in the presence of faults. The ESC is compared with other fault-tolerant multistage networks. Finally, reliability of the ESC and an enhanced version of it are investigated.

  9. Electric currents in networks of interconnected memristors

    NASA Astrophysics Data System (ADS)

    Nedaaee Oskoee, Ehsan; Sahimi, Muhammad

    2011-03-01

    Chua [IEEE Trans. Circuit TheoryIECTAF0018-932410.1109/TCT.1971.1083337 1, 507 (1971).] argued that, in addition to the standard resistors, capacitors, and inductors, there must be a fourth fundamental element in electrical circuits, which he called a memory resistor or memristor. Strukov [Nature (London)NATUAS0028-083610.1038/nature06932 453, 80 (2008)] showed how memristive behavior arises in some thin semiconducting films. Unlike other passive elements, however, a memristor with large sizes cannot be fabricated, because scale up of a memristor to dimensions of the order of microns causes loss of the memristive effect by decreasing the width of the doped region relative to the overall size of the memristor. A microscale memristor is, however, essential to most of the potential applications. One way of fabricating such a microscale memristor without losing the memristive effect is to make a network of very small interconnected memristors. We report the results of numerical simulations of electrical currents in such networks of interconnected memristors, as well as memristors and Ohmic conductors. The memristor networks exhibit a rich variety of interesting properties, including weakly and strongly memristive regimes, a possible first-order transition at the connectivity threshold, generation of second harmonics in the strongly memristive regime, and the universal dependence of the network’s strength on the frequency. Moreover, we show that the polarity of the memristors can play an important role in the overall properties of the memristor network, in particular its speed of switching, which may have a potentially important application to faster computers. None of these properties are exhibited by linear resistor networks, or even by nonlinear resistor networks without a memory effect.

  10. Adaptive control of nonlinear systems using multistage dynamic neural networks

    NASA Astrophysics Data System (ADS)

    Gupta, Madan M.; Rao, Dandina H.

    1992-11-01

    In this paper we present a new architecture of neuron, called the dynamic neural unit (DNU). The topology of the proposed neuronal model embodies delay elements, feedforward and feedback signals weighted by the synaptic weights and a time-varying nonlinear activation function, and is thus different from the conventionally and assumed architecture of neurons. The learning algorithm for the proposed neuronal structure and the corresponding implementation scheme are presented. A multi-stage dynamic neural network is developed using the DNU as the basic processing element. The performance evaluation of the dynamic neural network is presented for nonlinear dynamic systems under various situations. The capabilities of the proposed neural network model not only account for the learning and control actions emulating some of the biological control functions, but also provide a promising parallel-distributed intelligent control scheme for large-scale complex dynamic systems.

  11. A new interconnection network for SIMD computers: The sigma network

    SciTech Connect

    Seznec, A.

    1987-07-01

    When processing vectors on SIMD computers, some data manipulations (rearrangement, expansion, compression, perfect-shuffle, bit-reversal) have to be performed by an inter-connection network. When this network lacks an efficient routing control, it becomes the bottleneck for performance. It has been pointed out that general algorithms to control rearrangeable networks for arbitrary permutations are time consuming. To overcome this difficulty, Lenfant proposed a set of permutations covering standard needs associated with efficient control algorithms for the Benes network. But to perform explicit permutations on vectors, several passes through the network are necessary because they have to be composed with transfer rearrangements. The author presents efficient control algorithms to perform these vector permutations in a single pass on a new interconnection network.

  12. Massive parallel optical systems with nearest-neighbor interconnections

    NASA Astrophysics Data System (ADS)

    Giglmayr, Josef

    1995-08-01

    Two basic architectures are deduced from 1D multistage architectures with nearest-neighbor (NN) interconnection of switches and extended into 2D architectures by a mathematical transformation. These two architectures are the Spanke-Benes (SB) network and the NN multistage interconnection network of switches (NN-MIN). The properties and applications of the two 2D architectures are described.

  13. Oscillations in interconnected complex networks under intentional attack

    NASA Astrophysics Data System (ADS)

    Zhang, Wen-Ping; Xia, Yongxiang; Tan, Fei

    2016-01-01

    Many real-world networks are interconnected with each other. In this paper, we study the traffic dynamics in interconnected complex networks under an intentional attack. We find that with the shortest time delay routing strategy, the traffic dynamics can show the stable state, periodic, quasi-periodic and chaotic oscillations, when the capacity redundancy parameter changes. Moreover, compared with isolated complex networks, oscillations always take place in interconnected networks more easily. Thirdly, in interconnected networks, oscillations are affected strongly by the coupling probability and coupling preference.

  14. Fault-tolerant interconnection networks for multiprocessor systems

    SciTech Connect

    Nassar, H.M.

    1989-01-01

    Interconnection networks represent the backbone of multiprocessor systems. A failure in the network, therefore, could seriously degrade the system performance. For this reason, fault tolerance has been regarded as a major consideration in interconnection network design. This thesis presents two novel techniques to provide fault tolerance capabilities to three major networks: the Beneline network and the Clos network. First, the Simple Fault Tolerance Technique (SFT) is presented. The SFT technique is in fact the result of merging two widely known interconnection mechanisms: a normal interconnection network and a shared bus. This technique is most suitable for networks with small switches, such as the Baseline network and the Benes network. For the Clos network, whose switches may be large for the SFT, another technique is developed to produce the Fault-Tolerant Clos (FTC) network. In the FTC, one switch is added to each stage. The two techniques are described and thoroughly analyzed.

  15. Compact Interconnection Networks Based on Quantum Dots

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Toomarian, Nikzad; Modarress, Katayoon; Spotnitz, Matthew

    2003-01-01

    Architectures that would exploit the distinct characteristics of quantum-dot cellular automata (QCA) have been proposed for digital communication networks that connect advanced digital computing circuits. In comparison with networks of wires in conventional very-large-scale integrated (VLSI) circuitry, the networks according to the proposed architectures would be more compact. The proposed architectures would make it possible to implement complex interconnection schemes that are required for some advanced parallel-computing algorithms and that are difficult (and in many cases impractical) to implement in VLSI circuitry. The difficulty of implementation in VLSI and the major potential advantage afforded by QCA were described previously in Implementing Permutation Matrices by Use of Quantum Dots (NPO-20801), NASA Tech Briefs, Vol. 25, No. 10 (October 2001), page 42. To recapitulate: Wherever two wires in a conventional VLSI circuit cross each other and are required not to be in electrical contact with each other, there must be a layer of electrical insulation between them. This, in turn, makes it necessary to resort to a noncoplanar and possibly a multilayer design, which can be complex, expensive, and even impractical. As a result, much of the cost of designing VLSI circuits is associated with minimization of data routing and assignment of layers to minimize crossing of wires. Heretofore, these considerations have impeded the development of VLSI circuitry to implement complex, advanced interconnection schemes. On the other hand, with suitable design and under suitable operating conditions, QCA-based signal paths can be allowed to cross each other in the same plane without adverse effect. In principle, this characteristic could be exploited to design compact, coplanar, simple (relative to VLSI) QCA-based networks to implement complex, advanced interconnection schemes. The proposed architectures require two advances in QCA-based circuitry beyond basic QCA-based binary

  16. Cascading failures in interconnected networks with dynamical redistribution of loads

    NASA Astrophysics Data System (ADS)

    Zhao, Zhuang; Zhang, Peng; Yang, Hujiang

    2015-09-01

    Cascading failures of loads in isolated networks and coupled networks have been studied in the past few years. In most of the corresponding results, the topologies of the networks are destroyed. Here, we present an interconnected network model considering cascading failures based on the dynamic redistribution of flow in the networks. Compared with the results of single scale-free networks, we find that interconnected scale-free networks have higher vulnerability. Additionally, the network heterogeneity plays an important role in the robustness of interconnected networks under intentional attacks. Considering the effects of various coupling preferences, the results show that there are almost no differences. Finally, the application of our model to the Beijing interconnected traffic network, which consists of a subway network and a bus network, shows that the subway network suffers more damage under the attack. Moreover, the interconnected traffic network may be more exposed to damage after initial attacks on the bus network. These discussions are important for the design and optimization of interconnected networks.

  17. High throughput network for multiprocessor interconnections

    NASA Astrophysics Data System (ADS)

    Raatikainen, Pertti; Zidbeck, Juha

    1993-05-01

    Multiprocessor architectures are needed to support modern broadband applications, since traditional bus structures are not capable of providing high throughput. New bus structures are needed, especially in the area of network components and terminals. A study to find an efficient and cost effective interconnection topology for the future high speed products is presented. The most common bus topologies are introduced, and their characteristics are estimated to decide which one of them offers best performance and lowest implementation cost. The ring topology is chosen to be studied in more detail. Four competing bus access schemes for the high throughput ring are introduced as well as simulation models for each of them. Using transfer delay and throughput results, as well as keeping the implementation point of view in mind, the best candidate is selected to be studied and experimented in the succeeding research project.

  18. Maximizing algebraic connectivity in interconnected networks

    NASA Astrophysics Data System (ADS)

    Shakeri, Heman; Albin, Nathan; Darabi Sahneh, Faryad; Poggi-Corradini, Pietro; Scoglio, Caterina

    2016-03-01

    Algebraic connectivity, the second eigenvalue of the Laplacian matrix, is a measure of node and link connectivity on networks. When studying interconnected networks it is useful to consider a multiplex model, where the component networks operate together with interlayer links among them. In order to have a well-connected multilayer structure, it is necessary to optimally design these interlayer links considering realistic constraints. In this work, we solve the problem of finding an optimal weight distribution for one-to-one interlayer links under budget constraint. We show that for the special multiplex configurations with identical layers, the uniform weight distribution is always optimal. On the other hand, when the two layers are arbitrary, increasing the budget reveals the existence of two different regimes. Up to a certain threshold budget, the second eigenvalue of the supra-Laplacian is simple, the optimal weight distribution is uniform, and the Fiedler vector is constant on each layer. Increasing the budget past the threshold, the optimal weight distribution can be nonuniform. The interesting consequence of this result is that there is no need to solve the optimization problem when the available budget is less than the threshold, which can be easily found analytically.

  19. Three-dimensional multistage network applying for facial images decomposition

    NASA Astrophysics Data System (ADS)

    Timchenko, Leonid I.; Chepornyuk, Serge V.; Grudin, Maxim A.; Harvey, David M.; Kutaev, Yuri F.; Gertsiy, Alexander A.; Zahoruiko, Lubov V.

    1997-09-01

    The paper presents a novel three-dimensional network and its application to pattern analysis. This is a multistage architecture which investigates partial correlations between structural image components. Initially the image is partitioned to be processed in parallel channels. In each channel, the structural components are transformed and subsequently separated depending on their informational activity, to be mixed with the components from other channels for further processing. An output result is represented as a pattern vector, whose components are computed one at a time to allow the quickest possible response. The paper presents an algorithm applied to facial images decomposition. The input gray-scale image is transformed so that each pixel contains information about the spatial structure of its neighborhood. A three-level representation of gray-scale image is used in order for each pixel to contain the maximum amount of structural information. The most correlated information is extracted first, making the algorithm tolerant to minor structural changes.

  20. Computer Network Interconnection: Problems and Prospects. Computer Science & Technology Series.

    ERIC Educational Resources Information Center

    Cotton, Ira W.

    This report examines the current situation regarding the interconnection of computer networks, especially packet switched networks (PSNs). The emphasis is on idntifying the barriers to interconnection and on surveying approaches to a solution, rather than recommending any single course of action. Sufficient organizational and technical background…

  1. Network motifs emerge from interconnections that favour stability

    NASA Astrophysics Data System (ADS)

    Angulo, Marco Tulio; Liu, Yang-Yu; Slotine, Jean-Jacques

    2015-10-01

    The microscopic principles organizing dynamic units in complex networks--from proteins to power generators--can be understood in terms of network `motifs’: small interconnection patterns that appear much more frequently in real networks than expected in random networks. When considered as small subgraphs isolated from a large network, these motifs are more robust to parameter variations, easier to synchronize than other possible subgraphs, and can provide specific functionalities. But one can isolate these subgraphs only by assuming, for example, a significant separation of timescales, and the origin of network motifs and their functionalities when embedded in larger networks remain unclear. Here we show that most motifs emerge from interconnection patterns that best exploit the intrinsic stability characteristics at different scales of interconnection, from simple nodes to whole modules. This functionality suggests an efficient mechanism to stably build complex systems by recursively interconnecting nodes and modules as motifs. We present direct evidence of this mechanism in several biological networks.

  2. Reaction-diffusion processes on interconnected scale-free networks

    NASA Astrophysics Data System (ADS)

    Garas, Antonios

    2015-08-01

    We study the two-particle annihilation reaction A +B →∅ on interconnected scale-free networks, using different interconnecting strategies. We explore how the mixing of particles and the process evolution are influenced by the number of interconnecting links, by their functional properties, and by the interconnectivity strategies in use. We show that the reaction rates on this system are faster than what was observed in other topologies, due to the better particle mixing that suppresses the segregation effect, in line with previous studies performed on single scale-free networks.

  3. Interconnection networks: improved routing methods for Clos and Benes networks

    SciTech Connect

    Carpinelli, J.D.

    1987-01-01

    Interconnection networks for use by multiprocessor systems are optimal in terms of area, but the routing algorithms used to set up these networks are suboptimal. This work improves routing on these networks using a four-fold approach. First, routing is examined in the matrix-decomposition domain; the new characteristic of partitioning is used to improve current algorithms in this class and to develop an algorithm that does not require backtracking. Second, edge coloring and matching on bipartite multigraphs are applied to routing on Clos networks. The regularity of the bipartite multigraph for routing applications is exploited to optimize a more-general edge-coloring algorithm. Third, double-coset decomposition is used to identify new properties of Benes networks and speed up routing for some permutations. Finally, the Tree-Connected Computer is used to parallelize the Looping Algorithm and reduce the setup time for Benes networks by a factor of O(lgN). It is also used to reduce the bandwidth requirements for the fastest current setup algorithm for the Complementary Benes network.

  4. Resistive synaptic interconnects for electronic neural networks

    NASA Technical Reports Server (NTRS)

    Lamb, J. L.; Thakoor, A. P.; Moopenn, A.; Khanna, S. K.

    1987-01-01

    The use of the alpha-Ge(1-x):Al(x) and alpha-Ge(1-x):Cu(x) alloys and Pt/Al2O3 cermet thin films as resistive interconnects for binary synaptic memory arrays is evaluated. The fabrication of the 10-20 microns long, 10 microns wide, and 0.1 micron thick interconnects from the alloys and cermet is described. The current-voltage and switching characteristics of the as-deposited films and the patterned test structure are studied. The resistivity, uniformity, stability, and compatibility of the interconnects are examined. It is observed that alpha-Ge(1-x):Cu(x) alloys have a wide resistivity range and low temperature coefficients of resistance; however, their long-term stability is limited due to their low crystallization temperature. It is detected that the alpha-Ge(1-x):Al(x) alloys have higher crystallization temperatures and their resistivity is not greatly affected by large changes in metal content. The Pt/Al2O3 samples display excellent stability, easy fabrication, and control of resistivity with metal content.

  5. Interconnecting PV on New York City's Secondary Network Distribution System

    SciTech Connect

    Anderson, K; Coddington, M; Burman, K; Hayter, S; Kroposki, B; Watson, and A

    2009-11-01

    The U.S. Department of Energy (DOE) has teamed with cities across the country through the Solar America Cities (SAC) partnership program to help reduce barriers and accelerate implementation of solar energy. The New York City SAC team is a partnership between the City University of New York (CUNY), the New York City Mayor s Office of Long-term Planning and Sustainability, and the New York City Economic Development Corporation (NYCEDC).The New York City SAC team is working with DOE s National Renewable Energy Laboratory (NREL) and Con Edison, the local utility, to develop a roadmap for photovoltaic (PV) installations in the five boroughs. The city set a goal to increase its installed PV capacity from1.1 MW in 2005 to 8.1 MW by 2015 (the maximum allowed in 2005). A key barrier to reaching this goal, however, is the complexity of the interconnection process with the local utility. Unique challenges are associated with connecting distributed PV systems to secondary network distribution systems (simplified to networks in this report). Although most areas of the country use simpler radial distribution systems to distribute electricity, larger metropolitan areas like New York City typically use networks to increase reliability in large load centers. Unlike the radial distribution system, where each customer receives power through a single line, a network uses a grid of interconnected lines to deliver power to each customer through several parallel circuits and sources. This redundancy improves reliability, but it also requires more complicated coordination and protection schemes that can be disrupted by energy exported from distributed PV systems. Currently, Con Edison studies each potential PV system in New York City to evaluate the system s impact on the network, but this is time consuming for utility engineers and may delay the customer s project or add cost for larger installations. City leaders would like to streamline this process to facilitate faster, simpler, and

  6. Cluster system using fiber channel as an interconnection network analysis

    NASA Astrophysics Data System (ADS)

    Yang, Yi; Cao, Mingcui; Luo, Zhixiang

    2005-02-01

    In the parallel processing system, large numbers of processors are interconnected in order to improve the performance of the computer, such as the symmetric multiprocessor (SMP) architecture. When the basic node is an SMP or a computer having a single processor, the characteristics of an interconnection networks are important factors which influence the performance of the entire system. Fibre Channel (FC) has a lot advantages, such as excellent scalability; the bandwidth is large; delay time is short and fault tolerance is large. It is assumed that an SMP is used for a basic node. We construct the cluster system using FC as interconnection network, which are a fabric method and a FC Arbitrated Loop (FC-AL) method. According the method, if the number of nodes supported by the interconnection network is small, the addition of extra nodes can be added at small expense. The bandwidth of each node is large, the delay time is short, and the fault tolerance effect is large in the interconnection network. In the case of connecting to a shared disk, a large bandwidth is provided and time required for gaining access to the shared disk becomes short.

  7. Ranking in interconnected multilayer networks reveals versatile nodes

    NASA Astrophysics Data System (ADS)

    de Domenico, Manlio; Solé-Ribalta, Albert; Omodei, Elisa; Gómez, Sergio; Arenas, Alex

    2015-04-01

    The determination of the most central agents in complex networks is important because they are responsible for a faster propagation of information, epidemics, failures and congestion, among others. A challenging problem is to identify them in networked systems characterized by different types of interactions, forming interconnected multilayer networks. Here we describe a mathematical framework that allows us to calculate centrality in such networks and rank nodes accordingly, finding the ones that play the most central roles in the cohesion of the whole structure, bridging together different types of relations. These nodes are the most versatile in the multilayer network. We investigate empirical interconnected multilayer networks and show that the approaches based on aggregating--or neglecting--the multilayer structure lead to a wrong identification of the most versatile nodes, overestimating the importance of more marginal agents and demonstrating the power of versatility in predicting their role in diffusive and congestion processes.

  8. Rescue of endemic states in interconnected networks with adaptive coupling.

    PubMed

    Vazquez, F; Serrano, M Ángeles; Miguel, M San

    2016-01-01

    We study the Susceptible-Infected-Susceptible model of epidemic spreading on two layers of networks interconnected by adaptive links, which are rewired at random to avoid contacts between infected and susceptible nodes at the interlayer. We find that the rewiring reduces the effective connectivity for the transmission of the disease between layers, and may even totally decouple the networks. Weak endemic states, in which the epidemics spreads when the two layers are interconnected but not in each layer separately, show a transition from the endemic to the healthy phase when the rewiring overcomes a threshold value that depends on the infection rate, the strength of the coupling and the mean connectivity of the networks. In the strong endemic scenario, in which the epidemics is able to spread on each separate network -and therefore on the interconnected system- the prevalence in each layer decreases when increasing the rewiring, arriving to single network values only in the limit of infinitely fast rewiring. We also find that rewiring amplifies finite-size effects, preventing the disease transmission between finite networks, as there is a non zero probability that the epidemics stays confined in only one network during its lifetime. PMID:27380771

  9. Rescue of endemic states in interconnected networks with adaptive coupling

    NASA Astrophysics Data System (ADS)

    Vazquez, F.; Serrano, M. Ángeles; Miguel, M. San

    2016-07-01

    We study the Susceptible-Infected-Susceptible model of epidemic spreading on two layers of networks interconnected by adaptive links, which are rewired at random to avoid contacts between infected and susceptible nodes at the interlayer. We find that the rewiring reduces the effective connectivity for the transmission of the disease between layers, and may even totally decouple the networks. Weak endemic states, in which the epidemics spreads when the two layers are interconnected but not in each layer separately, show a transition from the endemic to the healthy phase when the rewiring overcomes a threshold value that depends on the infection rate, the strength of the coupling and the mean connectivity of the networks. In the strong endemic scenario, in which the epidemics is able to spread on each separate network –and therefore on the interconnected system– the prevalence in each layer decreases when increasing the rewiring, arriving to single network values only in the limit of infinitely fast rewiring. We also find that rewiring amplifies finite-size effects, preventing the disease transmission between finite networks, as there is a non zero probability that the epidemics stays confined in only one network during its lifetime.

  10. Rescue of endemic states in interconnected networks with adaptive coupling

    PubMed Central

    Vazquez, F.; Serrano, M. Ángeles; Miguel, M. San

    2016-01-01

    We study the Susceptible-Infected-Susceptible model of epidemic spreading on two layers of networks interconnected by adaptive links, which are rewired at random to avoid contacts between infected and susceptible nodes at the interlayer. We find that the rewiring reduces the effective connectivity for the transmission of the disease between layers, and may even totally decouple the networks. Weak endemic states, in which the epidemics spreads when the two layers are interconnected but not in each layer separately, show a transition from the endemic to the healthy phase when the rewiring overcomes a threshold value that depends on the infection rate, the strength of the coupling and the mean connectivity of the networks. In the strong endemic scenario, in which the epidemics is able to spread on each separate network –and therefore on the interconnected system– the prevalence in each layer decreases when increasing the rewiring, arriving to single network values only in the limit of infinitely fast rewiring. We also find that rewiring amplifies finite-size effects, preventing the disease transmission between finite networks, as there is a non zero probability that the epidemics stays confined in only one network during its lifetime. PMID:27380771

  11. Using SPEEDES to simulate the blue gene interconnect network

    NASA Technical Reports Server (NTRS)

    Springer, P.; Upchurch, E.

    2003-01-01

    JPL and the Center for Advanced Computer Architecture (CACR) is conducting application and simulation analyses of BG/L in order to establish a range of effectiveness for the Blue Gene/L MPP architecture in performing important classes of computations and to determine the design sensitivity of the global interconnect network in support of real world ASCI application execution.

  12. Brain tumour cells interconnect to a functional and resistant network.

    PubMed

    Osswald, Matthias; Jung, Erik; Sahm, Felix; Solecki, Gergely; Venkataramani, Varun; Blaes, Jonas; Weil, Sophie; Horstmann, Heinz; Wiestler, Benedikt; Syed, Mustafa; Huang, Lulu; Ratliff, Miriam; Karimian Jazi, Kianush; Kurz, Felix T; Schmenger, Torsten; Lemke, Dieter; Gömmel, Miriam; Pauli, Martin; Liao, Yunxiang; Häring, Peter; Pusch, Stefan; Herl, Verena; Steinhäuser, Christian; Krunic, Damir; Jarahian, Mostafa; Miletic, Hrvoje; Berghoff, Anna S; Griesbeck, Oliver; Kalamakis, Georgios; Garaschuk, Olga; Preusser, Matthias; Weiss, Samuel; Liu, Haikun; Heiland, Sabine; Platten, Michael; Huber, Peter E; Kuner, Thomas; von Deimling, Andreas; Wick, Wolfgang; Winkler, Frank

    2015-12-01

    Astrocytic brain tumours, including glioblastomas, are incurable neoplasms characterized by diffusely infiltrative growth. Here we show that many tumour cells in astrocytomas extend ultra-long membrane protrusions, and use these distinct tumour microtubes as routes for brain invasion, proliferation, and to interconnect over long distances. The resulting network allows multicellular communication through microtube-associated gap junctions. When damage to the network occurred, tumour microtubes were used for repair. Moreover, the microtube-connected astrocytoma cells, but not those remaining unconnected throughout tumour progression, were protected from cell death inflicted by radiotherapy. The neuronal growth-associated protein 43 was important for microtube formation and function, and drove microtube-dependent tumour cell invasion, proliferation, interconnection, and radioresistance. Oligodendroglial brain tumours were deficient in this mechanism. In summary, astrocytomas can develop functional multicellular network structures. Disconnection of astrocytoma cells by targeting their tumour microtubes emerges as a new principle to reduce the treatment resistance of this disease. PMID:26536111

  13. Derivatives and credit contagion in interconnected networks

    NASA Astrophysics Data System (ADS)

    Heise, S.; Kühn, R.

    2012-04-01

    The importance of adequately modeling credit risk has once again been highlighted in the recent financial crisis. Defaults tend to cluster around times of economic stress due to poor macro-economic conditions, but also by directly triggering each other through contagion. Although credit default swaps have radically altered the dynamics of contagion for more than a decade, models quantifying their impact on systemic risk are still missing. Here, we examine contagion through credit default swaps in a stylized economic network of corporates and financial institutions. We analyse such a system using a stochastic setting, which allows us to exploit limit theorems to exactly solve the contagion dynamics for the entire system. Our analysis shows that, by creating additional contagion channels, CDS can actually lead to greater instability of the entire network in times of economic stress. This is particularly pronounced when CDS are used by banks to expand their loan books (arguing that CDS would offload the additional risks from their balance sheets). Thus, even with complete hedging through CDS, a significant loan book expansion can lead to considerably enhanced probabilities for the occurrence of very large losses and very high default rates in the system. Our approach adds a new dimension to research on credit contagion, and could feed into a rational underpinning of an improved regulatory framework for credit derivatives.

  14. Fiber-optic interconnection networks for spacecraft

    NASA Technical Reports Server (NTRS)

    Powers, Robert S.

    1992-01-01

    The overall goal of this effort was to perform the detailed design, development, and construction of a prototype 8x8 all-optical fiber optic crossbar switch using low power liquid crystal shutters capable of operation in a network with suitable fiber optic transmitters and receivers at a data rate of 1 Gb/s. During the earlier Phase 1 feasibility study, it was determined that the all-optical crossbar system had significant advantages compared to electronic crossbars in terms of power consumption, weight, size, and reliability. The result is primarily due to the fact that no optical transmitters and receivers are required for electro-optic conversion within the crossbar switch itself.

  15. Stuttgart Interconnection Network Project from PIX to NICS

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The PIX follow-up project NICS is described. The purpose of PIX was access to X.25, the DATEX-P network of the Federal German Post Office. The development and implementation of higher protocols for levels 4-7 in the ISOSINN was the actual problem here. Results of the PIX project are given. NICS (Stuttgart Interconnection Network Project) is presented. International Protocols are reviewed. PAD service is described, which allows terminal access to DATEX-P network of the Federal German Post Office.

  16. Reconfigurable optical interconnection network for multimode optical fiber sensor arrays

    NASA Technical Reports Server (NTRS)

    Chen, R. T.; Robinson, D.; Lu, H.; Wang, M. R.; Jannson, T.; Baumbick, R.

    1992-01-01

    A single-source, single-detector architecture has been developed to implement a reconfigurable optical interconnection network multimode optical fiber sensor arrays. The network was realized by integrating LiNbO3 electrooptic (EO) gratings working at the Raman Na regime and a massive fan-out waveguide hologram (WH) working at the Bragg regime onto a multimode glass waveguide. The glass waveguide utilized the whole substrate as a guiding medium. A 1-to-59 massive waveguide fan-out was demonstrated using a WH operating at 514 nm. Measured diffraction efficiency of 59 percent was experimentally confirmed. Reconfigurability of the interconnection was carried out by generating an EO grating through an externally applied electric field. Unlike conventional single-mode integrated optical devices, the guided mode demonstrated has an azimuthal symmetry in mode profile which is the same as that of a fiber mode.

  17. Design of scalable optical interconnection network using wavelength division multiplexing

    NASA Astrophysics Data System (ADS)

    Jing, Wencai; Tian, Jindong; Zhou, Ge; Zhang, Yimo; Liu, Wei; Zhang, Xun

    2000-04-01

    This paper describes the two-layer scalable wavelength routing optical interconnection network being developed in Tianjin University. The top layer of the network is multi- wavelength bi-directional optical bus, which has high bandwidth and low latency. The optical bus is made up of passive components, no wavelength-tunable devices have been sued. As a result, the optical bus has low communication latency that is mainly decided by the optical fiber length. The sub-layer of the network is single-wavelength ring, which has low communication latency and high-scalability. In each ring, a wavelength routing node is used for data transmission between the ring and the optical bus. Each node computer is connected to the ring using an optical network interface card, which is based on peripheral component interconnect bus. The communication latency inside the ring is decreased using synchronous pipelining transmission technique. The scale of the ring is mainly limited by the efficient bandwidth required by each node computer. The number of rings is mainly decided by the optical power of the laser diodes and the sensitivity of the optical detectors. If Erbium doped fiber amplifier is used in the optical bus, the scale of the network can be further developed.

  18. Construction of programmable interconnected 3D microfluidic networks

    NASA Astrophysics Data System (ADS)

    Hunziker, Patrick R.; Wolf, Marc P.; Wang, Xueya; Zhang, Bei; Marsch, Stephan; Salieb-Beugelaar, Georgette B.

    2015-02-01

    Microfluidic systems represent a key-enabling platform for novel diagnostic tools for use at the point-of-care in clinical contexts as well as for evolving single cell diagnostics. The design of 3D microfluidic systems is an active field of development, but construction of true interconnected 3D microfluidic networks is still a challenge, in particular when the goal is rapid prototyping, accurate design and flexibility. We report a novel approach for the construction of programmable 3D microfluidic systems consisting of modular 3D template casting of interconnected threads to allow user-programmable flow paths and examine its structural characteristics and its modular function. To overcome problems with thread template casting reported in the literature, low-surface-energy polymer threads were used, that allow solvent-free production. Connected circular channels with excellent roundness and low diameter variability were created. Variable channel termination allowed programming a flow path on-the-fly, thus rendering the resulting 3D microfluidic systems highly customizable even after production. Thus, construction of programmable/reprogrammable fully 3D microfluidic systems by template casting of a network of interconnecting threads is feasible, leads to high-quality and highly reproducible, complex 3D geometries.

  19. Interconnecting astronomical networks: evolving from single networks to meta-networks

    NASA Astrophysics Data System (ADS)

    White, R. R.; Allan, A.; Evans, S.; Vestrand, W. T.; Wren, J.; Wozniak, P.

    2006-06-01

    Over the past four years we have seen continued advancement in network technology and how those technologies are beginning to enable astronomical science. Even though some sociological aspects are hindering full cooperation between most observatories and telescopes outside of their academic or institutional connections, an unprecedented step during the summer of 2005 was taken towards creating a world-wide interconnection of astronomical assets. The Telescope Alert Operations Network System (TALONS), a centralized server/client bi-directional network developed and operated by Los Alamos National Laboratory, integrated one of its network nodes with a node from the eScience Telescopes for Astronomical Research (eSTAR), a peer-to-peer agent based network developed and operated by The University of Exeter. Each network can act independently, providing support for their direct clients, and by interconnection provide local clients with access to; outside telescope systems, software tools unavailable locally, and the ability to utilize assets far more efficiently, thereby enabling science on a world-wide scale. In this paper we will look at the evolution of these independent networks into the worlds first heterogeneous telescope network and where this may take astronomy in the future. We will also examine those key elements necessary to providing universal communication between diverse astronomical networks.

  20. Complexity in neuronal noise depends on network interconnectivity.

    PubMed

    Serletis, Demitre; Zalay, Osbert C; Valiante, Taufik A; Bardakjian, Berj L; Carlen, Peter L

    2011-06-01

    "Noise," or noise-like activity (NLA), defines background electrical membrane potential fluctuations at the cellular level of the nervous system, comprising an important aspect of brain dynamics. Using whole-cell voltage recordings from fast-spiking stratum oriens interneurons and stratum pyramidale neurons located in the CA3 region of the intact mouse hippocampus, we applied complexity measures from dynamical systems theory (i.e., 1/f(γ) noise and correlation dimension) and found evidence for complexity in neuronal NLA, ranging from high- to low-complexity dynamics. Importantly, these high- and low-complexity signal features were largely dependent on gap junction and chemical synaptic transmission. Progressive neuronal isolation from the surrounding local network via gap junction blockade (abolishing gap junction-dependent spikelets) and then chemical synaptic blockade (abolishing excitatory and inhibitory post-synaptic potentials), or the reverse order of these treatments, resulted in emergence of high-complexity NLA dynamics. Restoring local network interconnectivity via blockade washout resulted in resolution to low-complexity behavior. These results suggest that the observed increase in background NLA complexity is the result of reduced network interconnectivity, thereby highlighting the potential importance of the NLA signal to the study of network state transitions arising in normal and abnormal brain dynamics (such as in epilepsy, for example). PMID:21347547

  1. Robustness in clustering-based weighted inter-connected networks

    NASA Astrophysics Data System (ADS)

    Qiu, Yuzhuo; Yağan, Osman

    2014-04-01

    We study the robustness of symmetrically coupled and clustering-based weighted heterogeneous inter-connected networks with respect to load-failure-induced cascades. This is done under the assumption that the flow dynamics are governed by global redistribution of loads based on weighted betweenness centrality. Our results indicate that no weighting bias should be assigned to inter-links when calculating shortest path between node pairs under the clustering-based weighting scheme; i.e., inter-links shall be treated no differently than intra-links. In contrast with local load redistribution cases, we show that increasing connectivity is preferred for the robustness against global load redistribution-based cascading failures in clustering-based weighted inter-connected networks. Furthermore, comparisons among weighting schemes reveal that, both the clustering-based and degree-based schemes outperform the random one in the sense of requiring lower initial and total investments required to ensure robustness. We also find that clustering-based scheme outperforms degree-based one in terms of requiring lower initial investments. Except in a limited range where weighting is heavily suppressed, clustering-based scheme is shown to outperform degree-based one in terms of total investments. Finally, when there exists a hard investment budget constraint, clustering-based weighting scheme would be a better choice against a two-nodes-induced failure than the degree-based weighting, and the clustering-based scheme is more stable than degree-based scheme against one-or-two-nodes-induced failure. We expect our findings to be significantly useful in designing real-world weighted inter-connected networks that are robust against load-failure-induced cascades.

  2. A reconfigurable optoelectronic interconnect technology for multi-processor networks

    SciTech Connect

    Lu, Y.C.; Cheng, J.; Zolper, J.C.; Klem, J.

    1995-05-01

    This paper describes a new optical interconnect architecture and the integrated optoelectronic circuit technology for implementing a parallel, reconfigurable, multiprocessor network. The technology consists of monolithic array`s of optoelectronic switches that integrate vertical-cavity surface-emitting lasers with three-terminal heterojunction phototransistors, which effectively combined the functions of an optical transceiver and an optical spatial routing switch. These switches have demonstrated optical switching at 200 Mb/s, and electrical-to-optical data conversion at > 500 Mb/s, with a small-signal electrical-to-optical modulation bandwidth of {approximately} 4 GHz.

  3. LTAR linkages with other research networks: Capitalizing on network interconnections

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The USDA ARS Research Unit based at the Jornada Experimental Range outside of Las Cruces, NM, is a member of the USDA’s Long Term Agro-ecosystem Research (LTAR) Network, the National Science Foundation’s Long Term Ecological Research (LTER) Network, the National Ecological Observation Network (NEON)...

  4. Optical interconnections and networks; Proceedings of the Meeting, The Hague, Netherlands, Mar. 14, 15, 1990

    NASA Technical Reports Server (NTRS)

    Bartelt, Hartmut (Editor)

    1990-01-01

    The conference presents papers on interconnections, clock distribution, neural networks, and components and materials. Particular attention is given to a comparison of optical and electrical data interconnections at the board and backplane levels, a wafer-level optical interconnection network layout, an analysis and simulation of photonic switch networks, and the integration of picosecond GaAs photoconductive devices with silicon circuits for optical clocking and interconnects. Consideration is also given to the optical implementation of neural networks, invariance in an optoelectronic implementation of neural networks, and the recording of reversible patterns in polymer lightguides.

  5. Condition known to be sufficient for rearrangeability of the benes class of interconnection networks with 2*2 switches is also necessary

    SciTech Connect

    Kothari, S.C.; Lakshmivarahan, S.

    1983-01-01

    An n*n (n inputs and outputs) multistage interconnection network is said to be rearrangeable if it can realise all the possible connections of the n input terminals to the n output terminals in a one-to-one fashion. Starting with the pioneering works of Clos (1953) and Benes (1968) to this date a variety of sufficient conditions for rearrangeability are known in the literature. It is shown that the well known sufficient condition due to Benes on the link permutation is also necessary for rearrangeability if the network is made up of 2*2 switches. 15 references.

  6. Scaling silicon photonic switch fabrics for data center interconnection networks.

    PubMed

    Nikolova, Dessislava; Rumley, Sébastien; Calhoun, David; Li, Qi; Hendry, Robert; Samadi, Payman; Bergman, Keren

    2015-01-26

    With the rapidly increasing aggregate bandwidth requirements of data centers there is a growing interest in the insertion of optically interconnected networks with high-radix transparent optical switch fabrics. Silicon photonics is a particularly promising and applicable technology due to its small footprint, CMOS compatibility, high bandwidth density, and the potential for nanosecond scale dynamic connectivity. In this paper we analyze the feasibility of building silicon photonic microring based switch fabrics for data center scale optical interconnection networks. We evaluate the scalability of a microring based switch fabric for WDM signals. Critical parameters including crosstalk, insertion loss and switching speed are analyzed, and their sensitivity with respect to device parameters is examined. We show that optimization of physical layer parameters can reduce crosstalk and increase switch fabric scalability. Our analysis indicates that with current state-of-the-art devices, a high radix 128 × 128 silicon photonic single chip switch fabric with tolerable power penalty is feasible. The applicability of silicon photonic microrings for data center switching is further supported via review of microring operations and control demonstrations. The challenges and opportunities for this technology platform are discussed. PMID:25835876

  7. Architectural Exploration and Design Methodologies of Photonic Interconnection Networks

    NASA Astrophysics Data System (ADS)

    Chan, Jong Wu

    Photonic technology is becoming an increasingly attractive solution to the problems facing today's electronic chip-scale interconnection networks. Recent progress in silicon photonics research has enabled the demonstration of all the necessary optical building blocks for creating extremely high-bandwidth density and energy-efficient links for on- and off-chip communications. From the feasibility and architecture perspective however, photonics represents a dramatic paradigm shift from traditional electronic network designs due to fundamental differences in how electronics and photonics function and behave. As a result of these differences, new modeling and analysis methods must be employed in order to properly realize a functional photonic chip-scale interconnect design. In this work, we present a methodology for characterizing and modeling fundamental photonic building blocks which can subsequently be combined to form full photonic network architectures. We also describe a set of tools which can be utilized to assess the physical-layer and system-level performance properties of a photonic network. The models and tools are integrated in a novel open-source design and simulation environment called PhoenixSim. Next, we leverage PhoenixSim for the study of chip-scale photonic networks. We examine several photonic networks through the synergistic study of both physical-layer metrics and system-level metrics. This holistic analysis method enables us to provide deeper insight into architecture scalability since it considers insertion loss, crosstalk, and power dissipation. In addition to these novel physical-layer metrics, traditional system-level metrics of bandwidth and latency are also obtained. Lastly, we propose a novel routing architecture known as wavelength-selective spatial routing. This routing architecture is analogous to electronic virtual channels since it enables the transmission of multiple logical optical channels through a single physical plane (i.e. the

  8. LTAR Linkages with Other Research Networks: Capitalizing on Network Interconnections

    NASA Astrophysics Data System (ADS)

    Havstad, K.

    2015-12-01

    The USDA ARS Research Unit based at the Jornada Experimental Range outside of Las Cruces, NM, is a member of the USDA's Long Term Agro-ecosystem Research (LTAR) Network, the National Science Foundation's Long Term Ecological Research (LTER) Network, the National Ecological Observation Network (NEON), and the USDA's Climate Hub Network. Each of these networks has distinct functions, missions, operational characteristics, and distinct scientific and management sub-cultures (though some are fairly new and developing). Some are a fairly independent collection of research sites functioning as a network in name only, and others are truly working to develop a research synergy that could be holistic and uniquely productive. All have real scientific value, and collectively represent an investment in US research infrastructure in biology and agriculture in excess of $3B. To effectively utilize and exploit this unique research infrastructure will require a concerted effort to meld attributes of each to the benefits of their common stakeholders. Real opportunities exist to collectively utilize this infrastructure to address grand research challenges.

  9. Broadband packet switches based on dilated interconnection networks

    NASA Astrophysics Data System (ADS)

    Lee, Tony T.; Liew, Soung C.

    1994-02-01

    A theoretical foundation for evaluation and comparison of a very broad spectrum of fast packet-switching techniques is developed in this paper. Based on this framework, we investigate the complexity of various packet switch designs, and demonstrate the advantage of dilation as a switch-design technique. Packet switches are classified either as loss systems or waiting systems, according to whether packets losing contention are dropped or queued. In a loss system, the packet loss probability can be made arbitrary small by providing enough paths between inputs and outputs. We focus on the question: How does the switch complexity grow as a function of switch size for a given loss probability requirement? A uniform approach to this problem is developed here. We show that for an N x N switch, the required number of switch elements for both the parallel-banyan network and the tandem-banyan network is of order N(log N)(sup 2), whereas the complexity of a dilated-banyan network is of order N log N(log log N). Within the class of waiting systems, we show that the parallel banyan networks in a Batcher-parallel-banyan network can be replaced by a dilated-banyan network without sacrificing the nonblocking property. Thus, as with parallelization, dilation can also be used to increase the throughput of a waiting system. In addition, we also explore the application of dilation in a large modular switch design which is realized by an interconnection structure consisting of Batcher-dilated-banyan networks and statistical multiplexers.

  10. An efficient network for interconnecting remote monitoring instruments and computers

    SciTech Connect

    Halbig, J.K.; Gainer, K.E.; Klosterbuer, S.F.

    1994-08-01

    Remote monitoring instrumentation must be connected with computers and other instruments. The cost and intrusiveness of installing cables in new and existing plants presents problems for the facility and the International Atomic Energy Agency (IAEA). The authors have tested a network that could accomplish this interconnection using mass-produced commercial components developed for use in industrial applications. Unlike components in the hardware of most networks, the components--manufactured and distributed in North America, Europe, and Asia--lend themselves to small and low-powered applications. The heart of the network is a chip with three microprocessors and proprietary network software contained in Read Only Memory. In addition to all nonuser levels of protocol, the software also contains message authentication capabilities. This chip can be interfaced to a variety of transmission media, for example, RS-485 lines, fiber topic cables, rf waves, and standard ac power lines. The use of power lines as the transmission medium in a facility could significantly reduce cabling costs.

  11. Artificially modified magnetic anisotropy in interconnected nanowire networks

    NASA Astrophysics Data System (ADS)

    Araujo, Elsie; Encinas, Armando; Velázquez-Galván, Yenni; Martínez-Huerta, Juan Manuel; Hamoir, Gaël; Ferain, Etienne; Piraux, Luc

    2015-01-01

    Interconnected or crossed magnetic nanowire networks have been fabricated by electrodeposition into a polycarbonate template with crossed cylindrical nanopores oriented +/-30° with respect to the surface normal. Tailor-made nanoporous polymer membranes have been designed by performing a double energetic heavy ion irradiation with fixed incidence angles. The Ni and Ni/NiFe nanowire networks have been characterized by magnetometry as well as ferromagnetic resonance and compared with parallel nanowire arrays of the same diameter and density. The most interesting feature of these nanostructured materials is a significant reduction of the magnetic anisotropy when the external field is applied perpendicular and parallel to the plane of the sample. This effect is attributed to the relative orientation of the nanowire axes with the applied field. Moreover, the microwave transmission spectra of these nanowire networks display an asymmetric linewidth broadening, which may be interesting for the development of low-pass filters. Nanoporous templates made of well-defined nanochannel network constitute an interesting approach to fabricate materials with controlled anisotropy and microwave absorption properties that can be easily modified by adjusting the relative orientation of the nanochannels, pore sizes and material composition along the length of the nanowire.

  12. Exact coupling threshold for structural transition reveals diversified behaviors in interconnected networks

    NASA Astrophysics Data System (ADS)

    Darabi Sahneh, Faryad; Scoglio, Caterina; Van Mieghem, Piet

    2015-10-01

    An interconnected network features a structural transition between two regimes [F. Radicchi and A. Arenas, Nat. Phys. 9, 717 (2013), 10.1038/nphys2761]: one where the network components are structurally distinguishable and one where the interconnected network functions as a whole. Our exact solution for the coupling threshold uncovers network topologies with unexpected behaviors. Specifically, we show conditions that superdiffusion, introduced by Gómez et al. [Phys. Rev. Lett. 110, 028701 (2013), 10.1103/PhysRevLett.110.028701], can occur despite the network components functioning distinctly. Moreover, we find that components of certain interconnected network topologies are indistinguishable despite very weak coupling between them.

  13. High performance interconnection between high data rate networks

    NASA Technical Reports Server (NTRS)

    Foudriat, E. C.; Maly, K.; Overstreet, C. M.; Zhang, L.; Sun, W.

    1992-01-01

    The bridge/gateway system needed to interconnect a wide range of computer networks to support a wide range of user quality-of-service requirements is discussed. The bridge/gateway must handle a wide range of message types including synchronous and asynchronous traffic, large, bursty messages, short, self-contained messages, time critical messages, etc. It is shown that messages can be classified into three basic classes, synchronous and large and small asynchronous messages. The first two require call setup so that packet identification, buffer handling, etc. can be supported in the bridge/gateway. Identification enables resequences in packet size. The third class is for messages which do not require call setup. Resequencing hardware based to handle two types of resequencing problems is presented. The first is for a virtual parallel circuit which can scramble channel bytes. The second system is effective in handling both synchronous and asynchronous traffic between networks with highly differing packet sizes and data rates. The two other major needs for the bridge/gateway are congestion and error control. A dynamic, lossless congestion control scheme which can easily support effective error correction is presented. Results indicate that the congestion control scheme provides close to optimal capacity under congested conditions. Under conditions where error may develop due to intervening networks which are not lossless, intermediate error recovery and correction takes 1/3 less time than equivalent end-to-end error correction under similar conditions.

  14. The effect of capacity redundancy disparity on the robustness of interconnected networks

    NASA Astrophysics Data System (ADS)

    Xia, Yongxiang; Zhang, Wenping; Zhang, Xuejun

    2016-04-01

    Cascading failures in interconnected networks have received more and more attention. In previous works, the basic assumption is that networks share the same capacity redundancy. However, this setting cannot capture the real case very well. Hence, in this paper, we analyze the effect of capacity redundancy disparity on the robustness of interconnected networks. In isolated networks, it is well known that the complex network's robustness can be improved by increasing its capacity redundancy. In interconnected networks where two networks share the same capacity redundancy, the similar result holds. Yet this result is not necessarily true in interconnected networks where two networks are different in capacity redundancy. We find that when the capacity redundancy of one network is fixed, the robustness of the whole system may not follow another network's capacity redundancy. More specifically, when the fixed network's capacity redundancy is very small or very large, the robustness of the whole system increases as another network's capacity redundancy increases. But there exists a certain range within which the increase of one network's capacity redundancy results in the robustness decline of the whole system. This counterintuitive feature appears under different coupling patterns such as assortative, disassortative, or random coupling. This result advances our understanding of the robustness of interconnected networks.

  15. Highly porous metal oxide networks of interconnected nanotubes by atomic layer deposition.

    PubMed

    Li, Fengbin; Yao, Xueping; Wang, Zhaogen; Xing, Weihong; Jin, Wanqin; Huang, Jun; Wang, Yong

    2012-09-12

    Mesoporous metal oxide networks composed of interconnected nanotubes with ultrathin tube walls down to 3 nm and high porosity up to 90% were fabricated by atomic layer deposition (ALD) of alumina or titania onto templates of swelling-induced porous block copolymers. The nanotube networks possessed dual sets of interconnected pores separated by the tube wall whose thickness could be finely tuned by altering ALD cycles. Because of the excellent pore interconnectivity and high porosity, the alumina nanotube networks showed superior humidity-sensing performances. PMID:22888959

  16. A Multi-Stage Reverse Logistics Network Problem by Using Hybrid Priority-Based Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Lee, Jeong-Eun; Gen, Mitsuo; Rhee, Kyong-Gu

    Today remanufacturing problem is one of the most important problems regarding to the environmental aspects of the recovery of used products and materials. Therefore, the reverse logistics is gaining become power and great potential for winning consumers in a more competitive context in the future. This paper considers the multi-stage reverse Logistics Network Problem (m-rLNP) while minimizing the total cost, which involves reverse logistics shipping cost and fixed cost of opening the disassembly centers and processing centers. In this study, we first formulate the m-rLNP model as a three-stage logistics network model. Following for solving this problem, we propose a Genetic Algorithm pri (GA) with priority-based encoding method consisting of two stages, and introduce a new crossover operator called Weight Mapping Crossover (WMX). Additionally also a heuristic approach is applied in the 3rd stage to ship of materials from processing center to manufacturer. Finally numerical experiments with various scales of the m-rLNP models demonstrate the effectiveness and efficiency of our approach by comparing with the recent researches.

  17. Fault tolerance analysis of the class of rearrangeable interconnection networks

    SciTech Connect

    Pakzad, S. . Dept. of Electrical Engineering)

    1989-08-01

    This paper analyzes the fault tolerance characteristics of a range or rearrangeable {beta}-networks based on the concepts and the framework developed by S. Pakzad and S. Lakshmivarahan. These rearrangeable {beta}-networks include the Benes network, the Waksman network, the Joel network, and the serial network. In addition, this paper presents a comparative analysis of the aforementioned networks according to their hardware cost, performance, and degree of fault tolerance.

  18. Distributed computing for signal processing: modeling of asynchronous parallel computation. Appendix C. Fault-tolerant interconnection networks and image-processing applications for the PASM parallel processing systems. Final report

    SciTech Connect

    Adams, G.B.

    1984-12-01

    The demand for very-high-speed data processing coupled with falling hardware costs has made large-scale parallel and distributed computer systems both desirable and feasible. Two modes of parallel processing are single-instruction stream-multiple data stream (SIMD) and multiple instruction stream - multiple data stream (MIMD). PASM, a partitionable SIMD/MIMD system, is a reconfigurable multimicroprocessor system being designed for image processing and pattern recognition. An important component of these systems is the interconnection network, the mechanism for communication among the computation nodes and memories. Assuring high reliability for such complex systems is a significant task. Thus, a crucial practical aspect of an interconnection network is fault tolerance. In answer to this need, the Extra Stage Cube (ESC), a fault-tolerant, multistage cube-type interconnection network, is defined. The fault tolerance of the ESC is explored for both single and multiple faults, routing tags are defined, and consideration is given to permuting data and partitioning the ESC in the presence of faults. The ESC is compared with other fault-tolerant multistage networks. Finally, reliability of the ESC and an enhanced version of it are investigated.

  19. Calculus for network delays and a note on topologies of interconnection networks. Doctoral thesis

    SciTech Connect

    Cruz, R.L.

    1987-07-01

    A calculus is developed for obtaining bounds on delay in a buffered communication network that applies to a wide variety of models for network operation. The theory developed is different from traditional approaches to analyzing delay because the model used to describe the entry of data into the network is non-probabilistic. It is assumed that the data stream entered into the network by any given user satisfies burstiness constraints--that is, the quantity of data from the stream contained in any interval of time is less than a value that depends on the length of the interval. Given this model, it is shown that data traffic streams on each internal link of the network satisfy burstiness constraints. This allows attainment of upper bounds on network delay and buffering requirements. A mechanism called regulation is studied for enforcing burstiness constraints on an arbitrary data stream. The effect of employing these regulation mechanisms inside the network is noted. Theoretical design issues for topologies of interconnection networks are examined.

  20. Reliability theory for diffusion processes on interconnected networks

    NASA Astrophysics Data System (ADS)

    Khorramzadeh, Yasamin; Youssef, Mina; Eubank, Stephen

    2014-03-01

    We present the concept of network reliability as a framework to study diffusion dynamics in interdependent networks. We illustrate how different outcomes of diffusion processes, such as cascading failure, can be studied by estimating the reliability polynomial under different reliability rules. As an example, we investigate the effect of structural properties on diffusion dynamics for a few different topologies of two coupled networks. We evaluate the effect of varying the probability of failure propagating along the edges, both within a single network as well as between the networks. We exhibit the sensitivity of interdependent network reliability and connectivity to edge failures in each topology. Network Dynamics and Simulation Science Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia 24061, USA.

  1. Highly graphitized laterally interconnected SWCNT network synthesis via a sandwich-grown method

    NASA Astrophysics Data System (ADS)

    Teng, I.-Ju; Chen, Kai-Ling; Hsu, Hui-Lin; Jian, Sheng-Rui; Wang, Li-Chun; Chen, Jung-Hsuan; Wang, Wei-Hsiang; Kuo, Cheng-Tzu

    2011-04-01

    We present a sandwich-grown method for growing laterally interconnected single-walled carbon nanotube (SWCNT) networks with a high degree of graphitization by microwave plasma chemical vapour deposition (MPCVD). An Al2O3-supported Fe catalyst precursor layer deposited on an oxidized Si substrate with an upper Si cover is first pretreated in pure hydrogen, and then exposed to a gas mixture of methane/hydrogen for growth process at a lower growth temperature and a faster rate. The effects of various parameters, such as catalyst film thickness, gas flow rate, working pressure, growth time and plasma power, on the morphologies and structural characteristics of the SWCNT networks are investigated, and therefore provide the essential conditions for direct growth of laterally interconnected SWCNT networks. Analytical results demonstrate that the SWCNT-based lateral architecture comprises a mixture of graphene-sheet-wrapped catalyst particles and laterally interconnected nanotubes, isolated or branched or assembled into bundles. The results also show that the formation of the laterally interconnected SWCNT networks is related to the sandwich-like stack approach and the addition of an Al2O3 layer in the MPCVD process. The successful growth of lateral SWCNT networks provides new experimental information for simply and efficiently preparing lateral SWCNTs on unpatterned substrates, and opens a pathway to create network-structured nanotube-based devices.

  2. Mean-square displacement of particles in slightly interconnected polymer networks.

    PubMed

    Sarmiento-Gomez, Erick; Santamaría-Holek, Iván; Castillo, Rolando

    2014-01-30

    Structural and viscoelastic properties of slightly interconnected polymer networks immersed in a solvent have been studied in two cases: when the polymer network is building up and when the polymer network is shrinking stepwise in a controlled way. To accomplish this goal, the mean square displacement (MSD) of embedded microspheres in the polymer network was measured as a function of time, with diffusive wave spectroscopy. Particle motion was analyzed in terms of a model, based on a Fokker-Planck type equation, developed for describing particles in Brownian motion within a network that constrain their movement. The model reproduces well the experimental features observed in the MSD vs t curves. The variation of the parameters describing the structure of the network can be understood as the polymerization comes about, and also after the successive volume contractions. In addition, from the MSD curves, the complex shear moduli were obtained in a wide range of frequencies when the network is building up, and at the different shrinking states of the network. Our microrheological results give an insight about the dynamics of embedded particles in slightly interconnected networks, which were also compared with similar results for polymers without interconnections and polymer gels. PMID:24423025

  3. The interconnected rhizosphere: High network complexity dominates rhizosphere assemblages.

    PubMed

    Shi, Shengjing; Nuccio, Erin E; Shi, Zhou J; He, Zhili; Zhou, Jizhong; Firestone, Mary K

    2016-08-01

    While interactions between roots and microorganisms have been intensively studied, we know little about interactions among root-associated microbes. We used random matrix theory-based network analysis of 16S rRNA genes to identify bacterial networks associated with wild oat (Avena fatua) over two seasons in greenhouse microcosms. Rhizosphere networks were substantially more complex than those in surrounding soils, indicating the rhizosphere has a greater potential for interactions and niche-sharing. Network complexity increased as plants grew, even as diversity decreased, highlighting that community organisation is not captured by univariate diversity. Covariations were predominantly positive (> 80%), suggesting that extensive mutualistic interactions may occur among rhizosphere bacteria; we identified quorum-based signalling as one potential strategy. Putative keystone taxa often had low relative abundances, suggesting low-abundance taxa may significantly contribute to rhizosphere function. Network complexity, a previously undescribed property of the rhizosphere microbiome, appears to be a defining characteristic of this habitat. PMID:27264635

  4. Interconnecting network for switching data packets and method for switching data packets

    DOEpatents

    Benner, Alan Frederic; Minkenberg, Cyriel Johan Agnes; Stunkel, Craig Brian

    2010-05-25

    The interconnecting network for switching data packets, having data and flow control information, comprises a local packet switch element (S1) with local input buffers (I(1,1) . . . I(1,y)) for buffering the incoming data packets, a remote packet switch element (S2) with remote input buffers (I(2,1) . . . I(2,y)) for buffering the incoming data packets, and data lines (L) for interconnecting the local and the remote packet switch elements (S1, S2). The interconnecting network further comprises a local and a remote arbiter (A1, A2) which are connected via control lines (CL) to the input buffers (I(1,1) . . . I(1,y), I(2,1) . . . I(2,y)), and which are formed such that they can provide that the flow control information is transmitted via the data lines (L) and the control lines (CL).

  5. Fuzzy-information-based robustness of interconnected networks against attacks and failures

    NASA Astrophysics Data System (ADS)

    Zhu, Qian; Zhu, Zhiliang; Wang, Yifan; Yu, Hai

    2016-09-01

    Cascading failure is fatal in applications and its investigation is essential and therefore became a focal topic in the field of complex networks in the last decade. In this paper, a cascading failure model is established for interconnected networks and the associated data-packet transport problem is discussed. A distinguished feature of the new model is its utilization of fuzzy information in resisting uncertain failures and malicious attacks. We numerically find that the giant component of the network after failures increases with tolerance parameter for any coupling preference and attacking ambiguity. Moreover, considering the effect of the coupling probability on the robustness of the networks, we find that the robustness of the assortative coupling and random coupling of the network model increases with the coupling probability. However, for disassortative coupling, there exists a critical phenomenon for coupling probability. In addition, a critical value that attacking information accuracy affects the network robustness is observed. Finally, as a practical example, the interconnected AS-level Internet in South Korea and Japan is analyzed. The actual data validates the theoretical model and analytic results. This paper thus provides some guidelines for preventing cascading failures in the design of architecture and optimization of real-world interconnected networks.

  6. SPRINT: The Systolic Processor with a Reconfigurable Interconnection Network of Transputers

    SciTech Connect

    De Groot, A.J.; Johansson, E.M.; Fitch, J.P.; Grant, C.W.; Parker, S.R.

    1987-05-01

    The Systolic Processor with a Reconfigurable Interconnection Network of Transputers (SPRINT) is a sixty-four-processor multiprocessor developed at Lawrence Livermore National Laboratory for experimentally evaluating systolic algorithms and architectures. This paper describes the architecture of the SPRINT and several algorithms which have been executed on it.

  7. Three-dimensional interconnected nickel phosphide networks with hollow microstructures and desulfurization performance

    SciTech Connect

    Zhang, Shuna; Zhang, Shujuan; Song, Limin; Wu, Xiaoqing; Fang, Sheng

    2014-05-01

    Graphical abstract: Three-dimensional interconnected nickel phosphide networks with hollow microstructures and desulfurization performance. - Highlights: • Three-dimensional Ni{sub 2}P has been prepared using foam nickel as a template. • The microstructures interconnected and formed sponge-like porous networks. • Three-dimensional Ni{sub 2}P shows superior hydrodesulfurization activity. - Abstract: Three-dimensional microstructured nickel phosphide (Ni{sub 2}P) was fabricated by the reaction between foam nickel (Ni) and phosphorus red. The as-prepared Ni{sub 2}P samples, as interconnected networks, maintained the original mesh structure of foamed nickel. The crystal structure and morphology of the as-synthesized Ni{sub 2}P were characterized by X-ray diffraction, scanning electron microscopy, automatic mercury porosimetry and X-ray photoelectron spectroscopy. The SEM study showed adjacent hollow branches were mutually interconnected to form sponge-like networks. The investigation on pore structure provided detailed information for the hollow microstructures. The growth mechanism for the three-dimensionally structured Ni{sub 2}P was postulated and discussed in detail. To investigate its catalytic properties, SiO{sub 2} supported three-dimensional Ni{sub 2}P was prepared successfully and evaluated for the hydrodesulfurization (HDS) of dibenzothiophene (DBT). DBT molecules were mostly hydrogenated and then desulfurized by Ni{sub 2}P/SiO{sub 2}.

  8. Optical interconnection network for parallel access to multi-rank memory in future computing systems.

    PubMed

    Wang, Kang; Gu, Huaxi; Yang, Yintang; Wang, Kun

    2015-08-10

    With the number of cores increasing, there is an emerging need for a high-bandwidth low-latency interconnection network, serving core-to-memory communication. In this paper, aiming at the goal of simultaneous access to multi-rank memory, we propose an optical interconnection network for core-to-memory communication. In the proposed network, the wavelength usage is delicately arranged so that cores can communicate with different ranks at the same time and broadcast for flow control can be achieved. A distributed memory controller architecture that works in a pipeline mode is also designed for efficient optical communication and transaction address processes. The scaling method and wavelength assignment for the proposed network are investigated. Compared with traditional electronic bus-based core-to-memory communication, the simulation results based on the PARSEC benchmark show that the bandwidth enhancement and latency reduction are apparent. PMID:26367901

  9. Exabits/s integrated photonic interconnection technology for flexible data-centric optical networks

    NASA Astrophysics Data System (ADS)

    Binh, Le N.; Tao, Thomas W.; Ning, Gordon L.

    2016-03-01

    Optical networking is evolving from classical service-provider base data-center centric (DCC) internetworking environment with massive capacity, hence demanding novel optical switching and interconnecting technologies. The traditional telecom networks are under a flattening transformation to meet challenges from DCC networks for massive capacity serving in order of multi-Pb/s. We present proposed distributed and concentric data center based networks and the essential optical interconnection technologies, from the photonic kernels to electronic and optoelectronic server clusters, in both passive and active structures. Optical switching devices and integrated matrices are proposed composing of tunable (bandwidth and center wavelength) optical filters and switches as well as resonant microring modulators (μRM)(switching and spectral demux/mux) for multi-wavelength flexible-bandwidth optical channels of aggregate capacity reaching Ebps. The design principles and some experimental results are also reported.

  10. Identifying Modular Flows on Multilayer Networks Reveals Highly Overlapping Organization in Interconnected Systems

    NASA Astrophysics Data System (ADS)

    De Domenico, Manlio; Lancichinetti, Andrea; Arenas, Alex; Rosvall, Martin

    2015-01-01

    To comprehend interconnected systems across the social and natural sciences, researchers have developed many powerful methods to identify functional modules. For example, with interaction data aggregated into a single network layer, flow-based methods have proven useful for identifying modular dynamics in weighted and directed networks that capture constraints on flow processes. However, many interconnected systems consist of agents or components that exhibit multiple layers of interactions, possibly from several different processes. Inevitably, representing this intricate network of networks as a single aggregated network leads to information loss and may obscure the actual organization. Here, we propose a method based on a compression of network flows that can identify modular flows both within and across layers in nonaggregated multilayer networks. Our numerical experiments on synthetic multilayer networks, with some layers originating from the same interaction process, show that the analysis fails in aggregated networks or when treating the layers separately, whereas the multilayer method can accurately identify modules across layers that originate from the same interaction process. We capitalize on our findings and reveal the community structure of two multilayer collaboration networks with topics as layers: scientists affiliated with the Pierre Auger Observatory and scientists publishing works on networks on the arXiv. Compared to conventional aggregated methods, the multilayer method uncovers connected topics and reveals smaller modules with more overlap that better capture the actual organization.

  11. Sub-Wavelength Silicon Photonic Devices for Optical Interconnect Networks

    NASA Astrophysics Data System (ADS)

    Dudley, Eric F.

    As our demand for information grows, so too does the demand for networks capable of handling this flood of data. Conventional on-chip electrical networks are approaching their limits in terms of latency, power consumption and data rates and will need to be replaced with new technology in the near future. Photonic networks promise great improvements over electrical networks, but several key challenges still hinder their widespread deployment. This thesis focuses on addressing the problem of encoding and routing data inside integrated optical communication networks. This is accomplished through electrically driven optical switches or modulators that are able to produce a binary optical data stream from a binary electrical input signal. The primary metrics used to evaluate the performance of these devices are spatial footprint, modulation/switching speed, operating voltage and power consumption per bit. Secondary concerns are device bandwidth, CMOS compatibility, tolerance to fabrication errors and device losses. In this thesis, we present a theoretical design for an electrically driven optical switch utilizing hybrid silicon-insulator-metal waveguides with a 30 square micrometer footprint, 57 Gbit/s switching speed, 2.6 fJ/bit power consumption and 1V operation. We also present experimental confirmation of the optical properties of hybrid silicon-insulator-metal waveguides which form the basis of this design.

  12. Multi-stage freezing of HEUR polymer networks with magnetite nanoparticles.

    PubMed

    Campanella, A; Holderer, O; Raftopoulos, K N; Papadakis, C M; Staropoli, M P; Appavou, M S; Müller-Buschbaum, P; Frielinghaus, H

    2016-04-01

    We observe a change in the segmental dynamics of hydrogels based on hydrophobically modified ethoxylated urethanes (HEUR) when hydrophobic magnetite nanoparticles (MNPs) are embedded in the hydrogels. The dynamics of the nanocomposite hydrogels is investigated using dielectric relaxation spectroscopy (DRS) and neutron spin echo (NSE) spectroscopy. The magnetic nanoparticles within the hydrophobic domains of the HEUR polymer network increase the size of these domains and their distance. The size increase leads to a dilution of the polymers close to the hydrophobic domain, allowing higher mobility of the smallest polymer blobs close to the "center". This is reflected in the decrease of the activation energy of the β-process detected in the DRS data. The increase in distance leads to an increase of the size of the largest hydrophilic polymer blobs. Therefore, the segmental dynamics of the largest blobs is slowed down. At short time scales, i.e. 10(-9) s < τ < 10(-3) s, the suppression of the segmental dynamics is reflected in the α-relaxation processes detected in the DRS data and in the decrease of the relaxation rate Γ of the segmental motion in the NSE data with increasing concentration of magnetic nanoparticles. The stepwise (multi-stage) freezing of the small blobs is only visible for the pure hydrogel at low temperatures. On the other hand, the glass transition temperature (Tg) decreases upon increasing the MNP loading, indicating an acceleration of the segmental dynamics at long time scales (τ∼ 100 s). Therefore, it would be possible to tune the Tg of the hydrogels by varying the MNP concentration. The contribution of the static inhomogeneities to the total scattering function Sst(q) is extracted from the NSE data, revealing a more ordered gel structure than the one giving rise to the total scattering function S(q), with a relaxed correlation length ξNSE = (43 ± 5) Å which is larger than the fluctuating correlation length from a static investigation

  13. Operational parameters of an opto-electronic neural network employing fixed planar holographic interconnects

    SciTech Connect

    Keller, P.E.; Gmitro, A.F.

    1993-07-01

    A prototype neutral network system of multifaceted, planar interconnection holograms and opto-electronic neurons is analyzed. This analysis shows that a hologram fabricated with electron-beam lithography has the capacity to connect 6700 neuron outputs to 6700 neuron inputs and that the encoded synaptic weights have a precision of approximately 5 bits. Higher interconnection densities can be achieved by accepting a lower synaptic weight accuracy. For systems employing laser diodes at the outputs of the neurons, processing rates in the range of 45 to 720 trillion connections per second can potentially be achieve.

  14. The Linked System Project : a network interconnection project between three major bibliographic utilities and LC

    NASA Astrophysics Data System (ADS)

    Kurihara, Shin'ichi

    The Linked Systems Project (LSP) is the first network project based on the Open Systems Interconnection (OSI) in the world. The purpose of the project is to interconnect between three major bibliographic utilities and LC, and to perform as one system on the whole. The first application developed for the LSP is the sharing of name authority data based on the Name Authority Cooperative (NACO) Project. In 1985, LC began to send name authority records to RLG/RLIN. Since 1987, RLG/RLIN and OCLC send name authority records to LC. Bibliographic records will be sent mutually between three major bibliographic utilities and LC near future.

  15. Cut set-based risk and reliability analysis for arbitrarily interconnected networks

    DOEpatents

    Wyss, Gregory D.

    2000-01-01

    Method for computing all-terminal reliability for arbitrarily interconnected networks such as the United States public switched telephone network. The method includes an efficient search algorithm to generate minimal cut sets for nonhierarchical networks directly from the network connectivity diagram. Efficiency of the search algorithm stems in part from its basis on only link failures. The method also includes a novel quantification scheme that likewise reduces computational effort associated with assessing network reliability based on traditional risk importance measures. Vast reductions in computational effort are realized since combinatorial expansion and subsequent Boolean reduction steps are eliminated through analysis of network segmentations using a technique of assuming node failures to occur on only one side of a break in the network, and repeating the technique for all minimal cut sets generated with the search algorithm. The method functions equally well for planar and non-planar networks.

  16. Interconnected Network Motifs Control Podocyte Morphology and Kidney Function

    PubMed Central

    Azeloglu, Evren U.; Hardy, Simon V.; Eungdamrong, Narat John; Chen, Yibang; Jayaraman, Gomathi; Chuang, Peter Y.; Fang, Wei; Xiong, Huabao; Neves, Susana R.; Jain, Mohit R.; Li, Hong; Ma’ayan, Avi; Gordon, Ronald E.; He, John Cijiang; Iyengar, Ravi

    2014-01-01

    Podocytes are kidney cells with specialized morphology that is required for glomerular filtration. Diseases, such as diabetes, or drug exposure that causes disruption of the podocyte foot process morphology results in kidney pathophysiology. Proteomic analysis of glomeruli isolated from rats with puromycin-induced kidney disease and control rats indicated that protein kinase A (PKA), which is activated by adenosine 3′,5′-monophosphate (cAMP), is a key regulator of podocyte morphology and function. In podocytes, cAMP signaling activates cAMP response element–binding protein (CREB) to enhance expression of the gene encoding a differentiation marker, synaptopodin, a protein that associates with actin and promotes its bundling. We constructed and experimentally verified a β-adrenergic receptor–driven network with multiple feedback and feedforward motifs that controls CREB activity. To determine how the motifs interacted to regulate gene expression, we mapped multicompartment dynamical models, including information about protein subcellular localization, onto the network topology using Petri net formalisms. These computational analyses indicated that the juxtaposition of multiple feedback and feedforward motifs enabled the prolonged CREB activation necessary for synaptopodin expression and actin bundling. Drug-induced modulation of these motifs in diseased rats led to recovery of normal morphology and physiological function in vivo. Thus, analysis of regulatory motifs using network dynamics can provide insights into pathophysiology that enable predictions for drug intervention strategies to treat kidney disease. PMID:24497609

  17. Interplay between the magnetic and magneto-transport properties of 3D interconnected nanowire networks

    NASA Astrophysics Data System (ADS)

    da Câmara Santa Clara Gomes, Tristan; De La Torre Medina, Joaquín; Velázquez-Galván, Yenni G.; Martínez-Huerta, Juan Manuel; Encinas, Armando; Piraux, Luc

    2016-07-01

    We have explored the interplay between the magnetic and magneto-transport properties of 3D interconnected nanowire networks made of various magnetic metals by electrodeposition into nanoporous membranes with crossed channels and controlled topology. The close relationship between their magnetic and structural properties has a direct impact on their magneto-transport behavior. In order to accurately and reliably describe the effective magnetic anisotropy and anisotropic magnetoresistance, an analytical model inherent to the topology of 3D nanowire networks is proposed and validated. The feasibility to obtain magneto-transport responses in nanowire network films based on interconnected nanowires makes them very attractive for the development of mechanically stable superstructures that are suitable for potential technological applications.

  18. Credit default swaps drawup networks: too interconnected to be stable?

    PubMed

    Kaushik, Rahul; Battiston, Stefano

    2013-01-01

    We analyse time series of CDS spreads for a set of major US and European institutions in a period overlapping the recent financial crisis. We extend the existing methodology of ε-drawdowns to the one of joint ε-drawups, in order to estimate the conditional probabilities of spike-like co-movements among pairs of spreads. After correcting for randomness and finite size effects, we find that, depending on the period of time, 50% of the pairs or more exhibit high probabilities of joint drawups and the majority of spread series are trend-reinforced, i.e. drawups tend to be followed by drawups in the same series. We then carry out a network analysis by taking the probability of joint drawups as a proxy of financial dependencies among institutions. We introduce two novel centrality-like measures that offer insights on how both the systemic impact of each node as well as its vulnerability to other nodes' shocks evolve in time. PMID:23843931

  19. Credit Default Swaps Drawup Networks: Too Interconnected to Be Stable?

    PubMed Central

    Kaushik, Rahul; Battiston, Stefano

    2013-01-01

    We analyse time series of CDS spreads for a set of major US and European institutions in a period overlapping the recent financial crisis. We extend the existing methodology of -drawdowns to the one of joint -drawups, in order to estimate the conditional probabilities of spike-like co-movements among pairs of spreads. After correcting for randomness and finite size effects, we find that, depending on the period of time, 50% of the pairs or more exhibit high probabilities of joint drawups and the majority of spread series are trend-reinforced, i.e. drawups tend to be followed by drawups in the same series. We then carry out a network analysis by taking the probability of joint drawups as a proxy of financial dependencies among institutions. We introduce two novel centrality-like measures that offer insights on how both the systemic impact of each node as well as its vulnerability to other nodes' shocks evolve in time. PMID:23843931

  20. An analysis of inhibitory pseudo-interconnections in unsupervised neural networks

    NASA Astrophysics Data System (ADS)

    Tran, Minh-Triet; Le, Nam Do-Hoang

    2013-12-01

    Lateral connection is a fundamental element of human neural networks which enables sparse learning and topographical order in feature maps. Due to high complexity and computational cost, computer scientists tend to simplify it in practical implementations. To utilize the simplicity of traditional networks while preserving the effects of interconnections, the authors employ numerical filters in unsupervised learning networks. These filters suppress low activations and decorrelate high ones, which are similar to how inhibitory lateral connections behave. Inhibitory networks outperform conventional approach in both standard datasets CIFAR-10 and STL-10. Our method also yields competitive results in comparison with other single-layer unsupervised networks. Furthermore, it is promising to apply inhibitory networks into deep learning systems for complex recognition problem.

  1. Highly reliable optical interconnection network on printed circuit board for distributed computer systems

    NASA Astrophysics Data System (ADS)

    Yu, Zhihua; Luo, Fengguang; Di, Xu; Zhou, Weilin; Li, Bin; Wang, Guangjun; Chen, Jun

    2010-11-01

    A highly reliable interchip optical interconnection network on a printed circuit board (PCB) was designed and realized, and experiments confirmed that the data rate in each channel could reach above 3.125 Gbps and the bit error rate (BER) could be up to 1.27×10 -18, which would be a good solution to the problem of communication bottlenecks between high-speed VLSI chips.

  2. Nature-inspired interconnects for self-assembled large-scale network-on-chip designs.

    PubMed

    Teuscher, Christof

    2007-06-01

    Future nanoscale electronics built up from an Avogadro number of components need efficient, highly scalable, and robust means of communication in order to be competitive with traditional silicon approaches. In recent years, the networks-on-chip (NoC) paradigm emerged as a promising solution to interconnect challenges in silicon-based electronics. Current NoC architectures are either highly regular or fully customized, both of which represent implausible assumptions for emerging bottom-up self-assembled molecular electronics that are generally assumed to have a high degree of irregularity and imperfection. Here, we pragmatically and experimentally investigate important design tradeoffs and properties of an irregular, abstract, yet physically plausible three-dimensional (3D) small-world interconnect fabric that is inspired by modern network-on-chip paradigms. We vary the framework's key parameters, such as the connectivity, number of switch nodes, and distribution of long- versus short-range connections, and measure the network's relevant communication characteristics. We further explore the robustness against link failures and the ability and efficiency to solve a simple toy problem, the synchronization task. The results confirm that (1) computation in irregular assemblies is a promising and disruptive computing paradigm for self-assembled nanoscale electronics and (2) that 3D small-world interconnect fabrics with a power-law decaying distribution of shortcut lengths are physically plausible and have major advantages over local two-dimensional and 3D regular topologies. PMID:17614693

  3. Nature-inspired interconnects for self-assembled large-scale network-on-chip designs

    NASA Astrophysics Data System (ADS)

    Teuscher, Christof

    2007-06-01

    Future nanoscale electronics built up from an Avogadro number of components need efficient, highly scalable, and robust means of communication in order to be competitive with traditional silicon approaches. In recent years, the networks-on-chip (NoC) paradigm emerged as a promising solution to interconnect challenges in silicon-based electronics. Current NoC architectures are either highly regular or fully customized, both of which represent implausible assumptions for emerging bottom-up self-assembled molecular electronics that are generally assumed to have a high degree of irregularity and imperfection. Here, we pragmatically and experimentally investigate important design tradeoffs and properties of an irregular, abstract, yet physically plausible three-dimensional (3D) small-world interconnect fabric that is inspired by modern network-on-chip paradigms. We vary the framework's key parameters, such as the connectivity, number of switch nodes, and distribution of long- versus short-range connections, and measure the network's relevant communication characteristics. We further explore the robustness against link failures and the ability and efficiency to solve a simple toy problem, the synchronization task. The results confirm that (1) computation in irregular assemblies is a promising and disruptive computing paradigm for self-assembled nanoscale electronics and (2) that 3D small-world interconnect fabrics with a power-law decaying distribution of shortcut lengths are physically plausible and have major advantages over local two-dimensional and 3D regular topologies.

  4. Prolonging the lifetime of wireless sensor networks interconnected to fixed network using hierarchical energy tree based routing algorithm.

    PubMed

    Kalpana, M; Dhanalakshmi, R; Parthiban, P

    2014-01-01

    This research work proposes a mathematical model for the lifetime of wireless sensor networks (WSN). It also proposes an energy efficient routing algorithm for WSN called hierarchical energy tree based routing algorithm (HETRA) based on hierarchical energy tree constructed using the available energy in each node. The energy efficiency is further augmented by reducing the packet drops using exponential congestion control algorithm (TCP/EXP). The algorithms are evaluated in WSNs interconnected to fixed network with seven distribution patterns, simulated in ns2 and compared with the existing algorithms based on the parameters such as number of data packets, throughput, network lifetime, and data packets average network lifetime product. Evaluation and simulation results show that the combination of HETRA and TCP/EXP maximizes longer network lifetime in all the patterns. The lifetime of the network with HETRA algorithm has increased approximately 3.2 times that of the network implemented with AODV. PMID:25535626

  5. Prolonging the Lifetime of Wireless Sensor Networks Interconnected to Fixed Network Using Hierarchical Energy Tree Based Routing Algorithm

    PubMed Central

    Kalpana, M.; Dhanalakshmi, R.; Parthiban, P.

    2014-01-01

    This research work proposes a mathematical model for the lifetime of wireless sensor networks (WSN). It also proposes an energy efficient routing algorithm for WSN called hierarchical energy tree based routing algorithm (HETRA) based on hierarchical energy tree constructed using the available energy in each node. The energy efficiency is further augmented by reducing the packet drops using exponential congestion control algorithm (TCP/EXP). The algorithms are evaluated in WSNs interconnected to fixed network with seven distribution patterns, simulated in ns2 and compared with the existing algorithms based on the parameters such as number of data packets, throughput, network lifetime, and data packets average network lifetime product. Evaluation and simulation results show that the combination of HETRA and TCP/EXP maximizes longer network lifetime in all the patterns. The lifetime of the network with HETRA algorithm has increased approximately 3.2 times that of the network implemented with AODV. PMID:25535626

  6. Nanostructured CuS networks composed of interconnected nanoparticles for asymmetric supercapacitors.

    PubMed

    Fu, Wenbin; Han, Weihua; Zha, Heming; Mei, Junfeng; Li, Yunxia; Zhang, Zemin; Xie, Erqing

    2016-09-21

    Nanostructured metal sulfides with excellent electrochemical activity and electrical conductivity are particularly promising for applications in high-performance energy storage devices. Here, we report on the facile synthesis of nanostructured CuS networks composed of interconnected nanoparticles as novel battery-type materials for asymmetric supercapacitors. We find that the CuS networks exhibit a high specific capacity of 49.8 mA g(-1) at a current density of 1 A g(-1), good rate capability and cycle stability. The superior performance could be attributed to the interconnected nanoparticles of CuS networks, which can facilitate electrolyte diffusion and provide fast electron pathways. Furthermore, an aqueous asymmetric supercapacitor has been assembled by using the CuS networks as the positive electrode and activated carbon as the negative electrode. The assembled device can work at a high operating voltage of 1.6 V and show a maximum energy density of 17.7 W h kg(-1) at a power density of 504 W kg(-1). This study indicates that the CuS networks have great potential for supercapacitor applications. PMID:27539193

  7. Generalized methodology for modeling and simulating optical interconnection networks using diffraction analysis

    NASA Astrophysics Data System (ADS)

    Louri, Ahmed; Major, Michael C.

    1995-07-01

    Research in the field of free-space optical interconnection networks has reached a point where simula-tors and other design tools are desirable for reducing development costs and for improving design time. Previously proposed methodologies have only been applicable to simple systems. Our goal was to develop a simulation methodology capable of evaluating the performance characteristics for a variety of different free-space networks under a range of different configurations and operating states. The proposed methodology operates by first establishing the optical signal powers at various locations in the network. These powers are developed through the simulation by diffraction analysis of the light propagation through the network. After this evaluation, characteristics such as bit-error rate, signal-to-noise ratio, and system bandwidth are calculated. Further, the simultaneous evaluation of this process for a set of component misalignments provides a measure of the alignment tolerance of a design. We discuss this simulation process in detail as well as provide models for different optical interconnection network components.

  8. An Interconnected Network of Core-Forming Melts Produced by Shear Deformation

    NASA Technical Reports Server (NTRS)

    Bruhn, D.; Groebner, N.; Kohlstedt, D. L.

    2000-01-01

    The formation mechanism of terrestrial planetary is still poorly understood, and has been the subject of numerous experimental studies. Several mechanisms have been proposed by which metal-mainly iron with some nickel-could have been extracted from a silicate mantle to form the core. Most recent models involve gravitational sinking of molten metal or metal sulphide through a partially or fully molten mantle that is often referred to as a'magma ocean. Alternative models invoke percolation of molten metal along an interconnected network (that is, porous flow) through a solid silicate matrix. But experimental studies performed at high pressures have shown that, under hydrostatic conditions, these melts do not form an interconnected network, leading to the widespread assumption that formation of metallic cores requires a magma ocean. In contrast, here we present experiments which demonstrate that shear deformation to large strains can interconnect a significant fraction of initially isolated pockets of metal and metal sulphide melts in a solid matrix of polycrystalline olivine. Therefore, in a dynamic (nonhydrostatic) environment, percolation remains a viable mechanism for the segregation and migration of core-forming melts in a solid silicate mantle.

  9. An interconnected network of core-forming melts produced by shear deformation

    PubMed

    Bruhn; Groebner; Kohlstedt

    2000-02-24

    The formation mechanism of terrestrial planetary cores is still poorly understood, and has been the subject of numerous experimental studies. Several mechanisms have been proposed by which metal--mainly iron with some nickel--could have been extracted from a silicate mantle to form the core. Most recent models involve gravitational sinking of molten metal or metal sulphide through a partially or fully molten mantle that is often referred to as a 'magma ocean'. Alternative models invoke percolation of molten metal along an interconnected network (that is, porous flow) through a solid silicate matrix. But experimental studies performed at high pressures have shown that, under hydrostatic conditions, these melts do not form an interconnected network, leading to the widespread assumption that formation of metallic cores requires a magma ocean. In contrast, here we present experiments which demonstrate that shear deformation to large strains can interconnect a significant fraction of initially isolated pockets of metal and metal sulphide melts in a solid matrix of polycrystalline olivine. Therefore, in a dynamic (non-hydrostatic) environment, percolation remains a viable mechanism for the segregation and migration of core-forming melts in a solid silicate mantle. PMID:10706283

  10. Experimental demonstration of the optical multi-mesh hypercube: scaleable interconnection network for multiprocessors and multicomputers

    NASA Astrophysics Data System (ADS)

    Louri, Ahmed; Furlonge, Stephen; Neocleous, Costas

    1996-12-01

    A prototype of a novel topology for scaleable optical interconnection networks called the optical multi-mesh hypercube (OMMH) is experimentally demonstrated to as high as a 150-Mbit s data rate (2 7 1 nonreturn-to-zero pseudo-random data pattern) at a bit error rate of 10 13 link by the use of commercially available devices. OMMH is a scaleable network Appl. Opt. 33, 7558 (1994); J. Lightwave Technol. 12, 704 (1994) architecture that combines the positive features of the hypercube (small diameter, connectivity, symmetry, simple routing, and fault tolerance) and the mesh (constant node degree and size scaleability). The optical implementation method is divided into two levels: high-density local connections for the hypercube modules, and high-bit-rate, low-density, long connections for the mesh links connecting the hypercube modules. Free-space imaging systems utilizing vertical-cavity surface-emitting laser (VCSEL) arrays, lenslet arrays, space-invariant holographic techniques, and photodiode arrays are demonstrated for the local connections. Optobus fiber interconnects from Motorola are used for the long-distance connections. The OMMH was optimized to operate at the data rate of Motorola s Optobus (10-bit-wide, VCSEL-based bidirectional data interconnects at 150 Mbits s). Difficulties encountered included the varying fan-out efficiencies of the different orders of the hologram, misalignment sensitivity of the free-space links, low power (1 mW) of the individual VCSEL s, and noise.

  11. The Dynamical Recollection of Interconnected Neural Networks Using Meta-heuristics

    NASA Astrophysics Data System (ADS)

    Kuremoto, Takashi; Watanabe, Shun; Kobayashi, Kunikazu; Feng, Laing-Bing; Obayashi, Masanao

    The interconnected recurrent neural networks are well-known with their abilities of associative memory of characteristic patterns. For example, the traditional Hopfield network (HN) can recall stored pattern stably, meanwhile, Aihara's chaotic neural network (CNN) is able to realize dynamical recollection of a sequence of patterns. In this paper, we propose to use meta-heuristic (MH) methods such as the particle swarm optimization (PSO) and the genetic algorithm (GA) to improve traditional associative memory systems. Using PSO or GA, for CNN, optimal parameters are found to accelerate the recollection process and raise the rate of successful recollection, and for HN, optimized bias current is calculated to improve the network with dynamical association of a series of patterns. Simulation results of binary pattern association showed effectiveness of the proposed methods.

  12. All-optical code routing in interconnected optical CDMA and WDM ring networks.

    PubMed

    Deng, Yanhua; Fok, Mable P; Prucnal, Paul R; Wang, Ting

    2010-11-01

    We propose an all-optical hybrid network composed of optical code division multiple access (CDMA) rings interconnecting through a reconfigurable wavelength division multiplexing (WDM) metro area ring. This network retains the advantages of both the optical CDMA and WDM techniques, including asynchronous access and differentiated quality of service, while removing the hard limit on the number of subscribers and increasing network flexibility. The all-optical network is enabled by using nonlinear optical loop mirrors in an add/drop router (ADR) that performs code conversion, dropping, and switching asynchronously. We experimentally demonstrate the functionalities of the ADR in the proposed scheme asynchronously and obtain error-free performance. The bit-error rate measurements show acceptable power penalties for different code routes. PMID:21042372

  13. Locus heterogeneity disease genes encode proteins with high interconnectivity in the human protein interaction network

    PubMed Central

    Keith, Benjamin P.; Robertson, David L.; Hentges, Kathryn E.

    2014-01-01

    Mutations in genes potentially lead to a number of genetic diseases with differing severity. These disease genes have been the focus of research in recent years showing that the disease gene population as a whole is not homogeneous, and can be categorized according to their interactions. Locus heterogeneity describes a single disorder caused by mutations in different genes each acting individually to cause the same disease. Using datasets of experimentally derived human disease genes and protein interactions, we created a protein interaction network to investigate the relationships between the products of genes associated with a disease displaying locus heterogeneity, and use network parameters to suggest properties that distinguish these disease genes from the overall disease gene population. Through the manual curation of known causative genes of 100 diseases displaying locus heterogeneity and 397 single-gene Mendelian disorders, we use network parameters to show that our locus heterogeneity network displays distinct properties from the global disease network and a Mendelian network. Using the global human proteome, through random simulation of the network we show that heterogeneous genes display significant interconnectivity. Further topological analysis of this network revealed clustering of locus heterogeneity genes that cause identical disorders, indicating that these disease genes are involved in similar biological processes. We then use this information to suggest additional genes that may contribute to diseases with locus heterogeneity. PMID:25538735

  14. Experimental demonstration of time-aware software defined networking for OpenFlow-based intra-datacenter optical interconnection networks

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Zhang, Jie; Zhao, Yongli; Ji, Yuefeng; Han, Jianrui; Lin, Yi; Qiu, Shaofeng; Lee, Young

    2014-06-01

    Nowadays, most service providers offer their services and support their applications through federated sets of data centers which need to be interconnected using high-capacity optical networks in intra-datacenter networks. Many datacenter applications in the environment require lower delay and higher availability with the end-to-end guaranteed quality of service. In this paper, we propose a novel time-aware software defined networking (TaSDN) architecture for OpenFlow-based intra-datacenter optical interconnection networks. Based on the proposed architecture, a time-aware service scheduling (TaSS) strategy is introduced to allocate the network and datacenter resources optimally, which considers the datacenter service scheduling with flexible service time and service bandwidth according to the various time sensitivity requirements. The TaSDN can arrange and accommodate the applications with required QoS considering the time factor, and enhance the data center responsiveness to quickly provide for intra-datacenter service demands. The overall feasibility of the proposed architecture is experimentally verified on our testbed with real OpenFlow-enabled tunable optical modules. The performance of TaSS strategy under heavy traffic load scenario is also evaluated based on TaSDN architecture in terms of blocking probability and resource occupation rate.

  15. Percolation in interdependent and interconnected networks: abrupt change from second- to first-order transitions.

    PubMed

    Hu, Yanqing; Ksherim, Baruch; Cohen, Reuven; Havlin, Shlomo

    2011-12-01

    Robustness of two coupled networks systems has been studied separately only for dependency coupling [Buldyrev et al., Nature (London) 464, 1025 (2010)] and only for connectivity coupling [Leicht and D'Souza, e-print arXiv:0907.0894]. Here we study, using a percolation approach, a more realistic coupled networks system where both interdependent and interconnected links exist. We find rich and unusual phase-transition phenomena including hybrid transition of mixed first and second order, i.e., discontinuities like in a first-order transition of the giant component followed by a continuous decrease to zero like in a second-order transition. Moreover, we find unusual discontinuous changes from second-order to first-order transition as a function of the dependency coupling between the two networks. PMID:22304164

  16. Percolation in interdependent and interconnected networks: Abrupt change from second- to first-order transitions

    NASA Astrophysics Data System (ADS)

    Hu, Yanqing; Ksherim, Baruch; Cohen, Reuven; Havlin, Shlomo

    2011-12-01

    Robustness of two coupled networks systems has been studied separately only for dependency coupling [Buldyrev , Nature (London)NATUAS0028-083610.1038/nature08932 464, 1025 (2010)] and only for connectivity coupling [Leicht and D’Souza, e-print arXiv:0907.0894]. Here we study, using a percolation approach, a more realistic coupled networks system where both interdependent and interconnected links exist. We find rich and unusual phase-transition phenomena including hybrid transition of mixed first and second order, i.e., discontinuities like in a first-order transition of the giant component followed by a continuous decrease to zero like in a second-order transition. Moreover, we find unusual discontinuous changes from second-order to first-order transition as a function of the dependency coupling between the two networks.

  17. Self-interconnecting Pt nanowire network electrode for electrochemical amperometric biosensor.

    PubMed

    Wang, Shuqi; Xu, Li-Ping; Liang, Hai-Wei; Yu, Shu-Hong; Wen, Yongqiang; Wang, Shutao; Zhang, Xueji

    2015-07-14

    One-dimensional Pt nanostructures are of considerable interest for the development of highly stable and sensitive electrochemical sensors. This paper describes a self-interconnecting Pt nanowire network electrode (PtNNE) for the detection of hydrogen peroxide (H2O2) and glucose with ultrahigh sensitivity and stability. The as-prepared PtNNE consists of polycrystalline nanowires with high-index facets along the side surface which provides more active surface atoms on kinks and steps, those ultralong nanowires being interconnected with each other to form a free-standing network membrane. The excellent structural features of the PtNNE promoted its performance as a Pt-based electrochemical sensor both in terms of electrocatalytic activity and stability. Amperometric measurements towards hydrogen peroxide were performed; the PtNNE sensor showed an extremely high sensitivity of 1360 μA mM(-1) cm(-2). This excellent sensitivity is mainly attributed to the high-index facets of the nanowires resulting in their superior electrocatalytic activity towards H2O2, and the interconnected nanowire network forming an "electron freeway" transport model, which could provide multiple electron pathways and fast electron transport on the electrode, leading to rapid reaction and sensitive signal detection. The as-prepared PtNNE also holds promise as an oxidase-based biosensor. As a proof of concept, a PtNNE-based glucose biosensor also showed an outstanding sensitivity as high as 114 μA mM(-1) cm(-2), a low detection limit of 1.5 μM, and an impressive detection range from 5 μM to 30 mM. PMID:26083932

  18. An approach to architecture 3D scaffold with interconnective microchannel networks inducing angiogenesis for tissue engineering.

    PubMed

    Sun, Jiaoxia; Wang, Yuanliang; Qian, Zhiyong; Hu, Chenbo

    2011-11-01

    The angiogenesis of 3D scaffold is one of the major current limitations in clinical practice tissue engineering. The new strategy of construction 3D scaffold with microchannel circulation network may improve angiogenesis. In this study, 3D poly(D: ,L: -lactic acid) scaffolds with controllable microchannel structures were fabricated using sacrificial sugar structures. Melt drawing sugar-fiber network produced by a modified filament spiral winding method was used to form the microchannel with adjustable diameters and porosity. This fabrication process was rapid, inexpensive, and highly scalable. The porosity, microchannel diameter, interconnectivity and surface topographies of the scaffold were characterized by scanning electron microscopy. Mechanical properties were evaluated by compression tests. The mean porosity values of the scaffolds were in the 65-78% and the scaffold exhibited microchannel structure with diameter in the 100-200 μm range. The results showed that the scaffolds exhibited an adequate porosity, interconnective microchannel network, and mechanical properties. The cell culture studies with endothelial cells (ECs) demonstrated that the scaffold allowed cells to proliferate and penetrate into the volume of the entire scaffold. Overall, these findings suggest that the fabrication process offers significant advantages and flexibility in generating a variety of non-cytotoxic tissue engineering scaffolds with controllable distributions of porosity and physical properties that could provide the necessary physical cues for ECs and further improve angiogenesis for tissue engineering. PMID:21861076

  19. CATO: a CAD tool for intelligent design of optical networks and interconnects

    NASA Astrophysics Data System (ADS)

    Chlamtac, Imrich; Ciesielski, Maciej; Fumagalli, Andrea F.; Ruszczyk, Chester; Wedzinga, Gosse

    1997-10-01

    Increasing communication speed requirements have created a great interest in very high speed optical and all-optical networks and interconnects. The design of these optical systems is a highly complex task, requiring the simultaneous optimization of various parts of the system, ranging from optical components' characteristics to access protocol techniques. Currently there are no computer aided design (CAD) tools on the market to support the interrelated design of all parts of optical communication systems, thus the designer has to rely on costly and time consuming testbed evaluations. The objective of the CATO (CAD tool for optical networks and interconnects) project is to develop a prototype of an intelligent CAD tool for the specification, design, simulation and optimization of optical communication networks. CATO allows the user to build an abstract, possible incomplete, model of the system, and determine its expected performance. Based on design constraints provided by the user, CATO will automatically complete an optimum design, using mathematical programming techniques, intelligent search methods and artificial intelligence (AI). Initial design and testing of a CATO prototype (CATO-1) has been completed recently. The objective was to prove the feasibility of combining AI techniques, simulation techniques, an optical device library and a graphical user interface into a flexible CAD tool for obtaining optimal communication network designs in terms of system cost and performance. CATO-1 is an experimental tool for designing packet-switching wavelength division multiplexing all-optical communication systems using a LAN/MAN ring topology as the underlying network. The two specific AI algorithms incorporated are simulated annealing and a genetic algorithm. CATO-1 finds the optimal number of transceivers for each network node, using an objective function that includes the cost of the devices and the overall system performance.

  20. A Visually Attractive "Interconnected Network of Ideas" for Organizing the Teaching and Learning of Descriptive Inorganic Chemistry

    ERIC Educational Resources Information Center

    Rodgers, Glen E.

    2014-01-01

    A visually attractive interconnected network of ideas that helps general and second-year inorganic chemistry students make sense of the descriptive inorganic chemistry of the main-group elements is presented. The eight network components include the periodic law, the uniqueness principle, the diagonal effect, the inert-pair effect, the…

  1. Formation of an interconnected network of iron melt at Earth’s lower mantle conditions

    SciTech Connect

    Shi, Crystal Y.; Zhang, Li; Yang, Wenge; Liu, Yijin; Wang, Junyue; Meng, Yue; Andrews, Joy C.; Mao, Wendy L.

    2013-10-06

    Core formation represents the most significant differentiation event in Earth’s history. Our planet’s present layered structure with a metallic core and an overlying mantle implies that there must be a mechanism to separate iron alloy from silicates in the initially accreted material. At upper mantle conditions, percolation has been ruled out as an efficient mechanism because of the tendency of molten iron to form isolated pockets at these pressures and temperatures. Here we present experimental evidence of a liquid iron alloy forming an interconnected melt network within a silicate perovskite matrix under pressure and temperature conditions of the Earth’s lower mantle. Using nanoscale synchrotron X-ray computed tomography, we image a marked transition in the shape of the iron-rich melt in three-dimensional reconstructions of samples prepared at varying pressures and temperatures using a laser-heated diamond-anvil cell. We find that, as the pressure increases from 25 to 64GPa, the iron distribution changes from isolated pockets to an interconnected network. Our results indicate that percolation could be a viable mechanism of core formation at Earth’s lower mantle conditions.

  2. Study on the energy-efficient scheme based on the interconnection of optical-network-units for next generation optical access network

    NASA Astrophysics Data System (ADS)

    Lv, Yunxin; Jiang, Ning; Qiu, Kun; Xue, Chenpeng

    2014-12-01

    An energy-efficient scheme based on the interconnection of optical network unit (ONU) is introduced, which can significantly reduce the energy consumption of the low-traffic operation. The energy consumption model for the ONU-interconnected optical access network (OAN) based on the electronic switch (ES) technology is established, and the energy efficiency of the proposed scheme is analyzed and compared with that of the OAN using optical switch (OS). The simulation results demonstrate that the ONU-interconnected scheme can efficiently reduce the energy consumption of OAN, and it shows a good energy consumption performance under daily traffic model.

  3. Estimating Urban Traffic Patterns through Probabilistic Interconnectivity of Road Network Junctions.

    PubMed

    Manley, Ed

    2015-01-01

    The emergence of large, fine-grained mobility datasets offers significant opportunities for the development and application of new methodologies for transportation analysis. In this paper, the link between routing behaviour and traffic patterns in urban areas is examined, introducing a method to derive estimates of traffic patterns from a large collection of fine-grained routing data. Using this dataset, the interconnectivity between road network junctions is extracted in the form of a Markov chain. This representation encodes the probability of the successive usage of adjacent road junctions, encoding routes as flows between decision points rather than flows along road segments. This network of functional interactions is then integrated within a modified Markov chain Monte Carlo (MCMC) framework, adapted for the estimation of urban traffic patterns. As part of this approach, the data-derived links between major junctions influence the movement of directed random walks executed across the network to model origin-destination journeys. The simulation process yields estimates of traffic distribution across the road network. The paper presents an implementation of the modified MCMC approach for London, United Kingdom, building an MCMC model based on a dataset of nearly 700000 minicab routes. Validation of the approach clarifies how each element of the MCMC framework contributes to junction prediction performance, and finds promising results in relation to the estimation of junction choice and minicab traffic distribution. The paper concludes by summarising the potential for the development and extension of this approach to the wider urban modelling domain. PMID:26009884

  4. Estimating Urban Traffic Patterns through Probabilistic Interconnectivity of Road Network Junctions

    PubMed Central

    Manley, Ed

    2015-01-01

    The emergence of large, fine-grained mobility datasets offers significant opportunities for the development and application of new methodologies for transportation analysis. In this paper, the link between routing behaviour and traffic patterns in urban areas is examined, introducing a method to derive estimates of traffic patterns from a large collection of fine-grained routing data. Using this dataset, the interconnectivity between road network junctions is extracted in the form of a Markov chain. This representation encodes the probability of the successive usage of adjacent road junctions, encoding routes as flows between decision points rather than flows along road segments. This network of functional interactions is then integrated within a modified Markov chain Monte Carlo (MCMC) framework, adapted for the estimation of urban traffic patterns. As part of this approach, the data-derived links between major junctions influence the movement of directed random walks executed across the network to model origin-destination journeys. The simulation process yields estimates of traffic distribution across the road network. The paper presents an implementation of the modified MCMC approach for London, United Kingdom, building an MCMC model based on a dataset of nearly 700000 minicab routes. Validation of the approach clarifies how each element of the MCMC framework contributes to junction prediction performance, and finds promising results in relation to the estimation of junction choice and minicab traffic distribution. The paper concludes by summarising the potential for the development and extension of this approach to the wider urban modelling domain. PMID:26009884

  5. Advancing interconnect density for spiking neural network hardware implementations using traffic-aware adaptive network-on-chip routers.

    PubMed

    Carrillo, Snaider; Harkin, Jim; McDaid, Liam; Pande, Sandeep; Cawley, Seamus; McGinley, Brian; Morgan, Fearghal

    2012-09-01

    The brain is highly efficient in how it processes information and tolerates faults. Arguably, the basic processing units are neurons and synapses that are interconnected in a complex pattern. Computer scientists and engineers aim to harness this efficiency and build artificial neural systems that can emulate the key information processing principles of the brain. However, existing approaches cannot provide the dense interconnect for the billions of neurons and synapses that are required. Recently a reconfigurable and biologically inspired paradigm based on network-on-chip (NoC) and spiking neural networks (SNNs) has been proposed as a new method of realising an efficient, robust computing platform. However, the use of the NoC as an interconnection fabric for large-scale SNNs demands a good trade-off between scalability, throughput, neuron/synapse ratio and power consumption. This paper presents a novel traffic-aware, adaptive NoC router, which forms part of a proposed embedded mixed-signal SNN architecture called EMBRACE (EMulating Biologically-inspiRed ArChitectures in hardwarE). The proposed adaptive NoC router provides the inter-neuron connectivity for EMBRACE, maintaining router communication and avoiding dropped router packets by adapting to router traffic congestion. Results are presented on throughput, power and area performance analysis of the adaptive router using a 90 nm CMOS technology which outperforms existing NoCs in this domain. The adaptive behaviour of the router is also verified on a Stratix II FPGA implementation of a 4 × 2 router array with real-time traffic congestion. The presented results demonstrate the feasibility of using the proposed adaptive NoC router within the EMBRACE architecture to realise large-scale SNNs on embedded hardware. PMID:22561008

  6. Optical grooming switch with regenerative functionality for transparent interconnection of networks.

    PubMed

    Vorreau, P; Sygletos, S; Parmigiani, F; Hillerkuss, D; Bonk, R; Petropoulos, P; Richardson, D J; Zarris, G; Simeonidou, D; Klonidis, D; Tomkos, I; Weerasuriya, R; Ibrahim, S; Ellis, A D; Cotter, D; Morais, R; Monteiro, P; Ben Ezra, S; Tsadka, S; Freude, W; Leuthold, J

    2009-08-17

    We demonstrate a regenerative optical grooming switch for buffer-less interconnection of metro/access and metro/core ring networks with switching functionality in time, space and wavelength domain. Key functionalities of the router are the traffic aggregation with time-slot interchanging (TSI) functionality, the WDM-to-ODTM multiplexing and the OTDM-to-WDM demultiplexing of high-speed channel into lower bit-rate tributaries as well as multi-wavelength all-optical 2R regeneration of several higher-speed signals. BER and Q-factor measurements of different switching scenarios show excellent performance with no error floor and Q-factors above 21 dB. PMID:19687996

  7. Methods to improve the bus throughput of node computer in optical interconnection network

    NASA Astrophysics Data System (ADS)

    Tang, Feng; Jing, Wencai; Zhang, Yimo; Zhou, Ge; Jia, Dagong; Kong, Fanmin; Sun, Zhixiang

    2005-02-01

    Both hardware and software are optimized simultaneously to improve the bus throughput of node computer in cluster computing network. A cost effective optical interconnection ring network is established using off-the-shelf PCs with windows operating system. A network adapter card ONIC is developed. Using ETDM and field program technique, the full bandwidth of the 32bit×33MHz PCI bus is reached in physical layer. In order to overcome the hardware and software data bottlenecks induced by using of general purpose platform such as PCs and Windows 2000 system, several methods are adopted to maximum the bus throughput of node computer. A user-level interface is designed to blur the kernel/user mode boundary of the software system, and bypass the OS overhead. Zero-copy DMA is realized. The bandwidth in application level using PIO and DMA transfer mode is improved 17 and 26 times respectively. The sustained bandwidth in application layer can reach 437.6Mbit/s. It"s also shown theoretically and experimentally that the selection of main board chipset, using memory space map, reasonable using of PIO and DMA transfer mode, using polling and large MTU will also improve the bus throughput of node computer considerably.

  8. Detection of the dominant direction of information flow and feedback links in densely interconnected regulatory networks

    PubMed Central

    Ispolatov, Iaroslav; Maslov, Sergei

    2008-01-01

    Background Finding the dominant direction of flow of information in densely interconnected regulatory or signaling networks is required in many applications in computational biology and neuroscience. This is achieved by first identifying and removing links which close up feedback loops in the original network and hierarchically arranging nodes in the remaining network. In mathematical language this corresponds to a problem of making a graph acyclic by removing as few links as possible and thus altering the original graph in the least possible way. The exact solution of this problem requires enumeration of all cycles and combinations of removed links, which, as an NP-hard problem, is computationally prohibitive even for modest-size networks. Results We introduce and compare two approximate numerical algorithms for solving this problem: the probabilistic one based on a simulated annealing of the hierarchical layout of the network which minimizes the number of "backward" links going from lower to higher hierarchical levels, and the deterministic, "greedy" algorithm that sequentially cuts the links that participate in the largest number of feedback cycles. We find that the annealing algorithm outperforms the deterministic one in terms of speed, memory requirement, and the actual number of removed links. To further improve a visual perception of the layout produced by the annealing algorithm, we perform an additional minimization of the length of hierarchical links while keeping the number of anti-hierarchical links at their minimum. The annealing algorithm is then tested on several examples of regulatory and signaling networks/pathways operating in human cells. Conclusion The proposed annealing algorithm is powerful enough to performs often optimal layouts of protein networks in whole organisms, consisting of around ~104 nodes and ~105 links, while the applicability of the greedy algorithm is limited to individual pathways with ~100 vertices. The considered examples

  9. Generalized schemes for access and alignment of data in parallel processors with self-routing interconnection networks

    SciTech Connect

    Boppana, R.V.; Raghavendra, C.S. )

    1991-02-01

    In this paper the authors give a generalized solution to the problem of conflict-free access of various templates of data of a matrix, when they are stored in memory units in a parallel processor. The important features of the method are: compact representation of a skewing scheme, simple address computation, use of self- routing schemes to set up the interconnection network, and a general framework for the study of skewing schemes. In the method, each template access of interest will be a linear permutation on the processor address. The linear permutation involved determines the types of templates accessible. For parallel access of the most important templates, namely, row, column, main diagonal, and square blocks, the interconnection network needs to realize only the class of linear-complement permutations. It is known that with Benes or Omega as the interconnection network, one can efficiently self-route these permutations; this compares favorably with the schemes proposed by other researchers who assume that a cross bar is available for processor-memory interconnections. Hence, the approach given in the paper can be used to solve the data alignment problem for the existing parallel machines such as IBM RP3, Cedar multiprocessor, and NYU Ultracomputer. This is a generalized solution to the data skewing problem and encompasses the previous efforts by other researchers as special cases.

  10. Dimensioning of 10 Gbit/s all-optical packet switched networks based on optical label swapping routers with multistage 2R regeneration.

    PubMed

    Puerto, G; Ortega, B; Manzanedo, M D; Martínez, A; Pastor, D; Capmany, J; Kovacs, G

    2006-10-30

    This paper describes both the experimental and theoretical investigations on the cascadability of all-optical routers in optical label swapping networks incorporating a multistage wavelength conversion with 2R regeneration. A full description of a novel experimental setup allows the packet by packet measurement up to 16 hops with 10 Gb/s payload showing 1 dB penalty with 10(-12) bit error rate. Similarly, the simulations on the system allow a prediction on the cascadability of the router up to 64 hops. PMID:19529426

  11. Design of T-shaped nanophotonic wire waveguide for optical interconnection in H-tree network.

    PubMed

    Kurt, H; Giden, I H; Citrin, D S

    2011-12-19

    Nanophotonic wire waveguides play an important role for the realization of highly dense integrated photonic circuits. The miniaturization of optoelectronic devices and realization of ultra-small integrated circuits strongly demand compact waveguide branches. T-shaped versions of nanophotonic wires are the first stage of both power splitting and optical-interconnection systems based on guided-wave optics; however, the acute transitions at the waveguide junctions typically induce huge bending losses in terms of radiated modes. Both 2D and 3D finite-difference time-domain methods are employed to monitor the efficient light propagation. By introducing appropriate combinations of dielectric posts around the dielectric-waveguide junctions within the 4.096μm×4.096μm region, we are able to reduce the bending losses dramatically and increase the transmission efficiency from low values of 18% in the absence of the dielectric posts to approximately 49% and 43% in 2D and 3D cases, respectively. These findings may lead to the implementation of such T-junctions in near-future high-density integrated photonics to deliver optical-clock signals via H-tree network. PMID:22274265

  12. Interconnection of private land mobile radio systems with the public switched telephone network in certain MHz bands--Federal Communications Commission. Final rule.

    PubMed

    1982-04-23

    This document adopts new rules to enable private radio communication systems licensed under Part 90 in the 800 MHz bands to interconnect with the facilities of the public switched telephone network. These rules are necessary to enable private licensees to better utilize their radio systems by allowing interconnected operation under certain conditions. An accompanying petition for rulemaking is dismissed as moot. PMID:10255452

  13. Standards in process: Foundation and profiles of ISDN (Integrated Services Digital Network) and OSI (Open Systems Interconnection) studies

    NASA Astrophysics Data System (ADS)

    Cerni, D. M.

    1984-12-01

    Telecommunication and computer technologies are merging, stimulating such global communication projects as the Integrated Services Digital Network (ISDN) and the Open Systems Interconnection (OSI) Reference Model. The systems of standards needed to ensure worldwide success of these projects are being developed. These efforts, of unprecedented complexity, are demanding an increase in knowledgeable dedicated standards workers. This report offers background material on the meaning, significance, and changing nature of standards and their development, both in the United States and internationally.

  14. Performance evaluation of time-aware enhanced software defined networking (TeSDN) for elastic data center optical interconnection.

    PubMed

    Yang, Hui; Zhang, Jie; Zhao, Yongli; Ji, Yuefeng; Li, Hui; Lin, Yi; Li, Gang; Han, Jianrui; Lee, Young; Ma, Teng

    2014-07-28

    Data center interconnection with elastic optical networks is a promising scenario to meet the high burstiness and high-bandwidth requirements of data center services. We previously implemented enhanced software defined networking over elastic optical network for data center application [Opt. Express 21, 26990 (2013)]. On the basis of it, this study extends to consider the time-aware data center service scheduling with elastic service time and service bandwidth according to the various time sensitivity requirements. A novel time-aware enhanced software defined networking (TeSDN) architecture for elastic data center optical interconnection has been proposed in this paper, by introducing a time-aware resources scheduling (TaRS) scheme. The TeSDN can accommodate the data center services with required QoS considering the time dimensionality, and enhance cross stratum optimization of application and elastic optical network stratums resources based on spectrum elasticity, application elasticity and time elasticity. The overall feasibility and efficiency of the proposed architecture is experimentally verified on our OpenFlow-based testbed. The performance of TaRS scheme under heavy traffic load scenario is also quantitatively evaluated based on TeSDN architecture in terms of blocking probability and resource occupation rate. PMID:25089383

  15. Frames: A simple characterization of permutations realized by frequently used networks

    NASA Astrophysics Data System (ADS)

    Cam, Hasan; Fortes, Jose A. B.

    1995-05-01

    Rearrangeable multistage networks such as the Benes network realize any permutation, yet their routing algorithms are not cost-effective. On the other hand, there exist inexpensive routing algorithms for nonrearrangeable networks, but no simple technique exists to characterize all the permutations realized on these networks. This paper introduces the concept of frame and shows how it can be used to characterize all the permutations realized on various multistage interconnection networks. They include subnetworks of baseline, Benes, and cascaded baseline and shuffle-exchange networks.

  16. Selective broadcast interconnection - A novel scheme for fiber-optic local-area networks

    NASA Technical Reports Server (NTRS)

    Marhic, M. E.; Birk, Y.; Tobagi, F. A.

    1985-01-01

    A passive, unswitched scheme is introduced for directly interconnecting N stations, each of which has C transmitters and receivers. Implementations using fiber optics with spatial multiplexing and optionally wavelength multiplexing are discussed. This scheme utilizes the same resources as standard topologies with C parallel buses but outperforms them in two respects: (1) the aggregate throughput is proportional to C squared rather than to C; and (2) the power of each transmitter need reach only N/C, instead of N, receivers.

  17. Comparison of two reconfigurable N×N interconnects for a recurrent neural network

    NASA Astrophysics Data System (ADS)

    Berger, Christoph; Collings, Neil; Pourzand, Ali R.; Volkel, Reinnard

    1996-11-01

    Two different methods of pattern replication (conventional and interlaced fan-out) have been investigated and experimentally tested in a reconfigurable 5X5 optical interconnect. Similar alignment problems due to imaging errors (field curvature) were observed in both systems. We conclude that of the two methods the interlaced fan-out is better suited to avoid these imaging errors, to reduce system size and to implement an optical feedback loop.

  18. Engineering interconnected 3D vascular networks in hydrogels using molded sodium alginate lattice as the sacrificial template.

    PubMed

    Wang, Xue-Ying; Jin, Zi-He; Gan, Bo-Wen; Lv, Song-Wei; Xie, Min; Huang, Wei-Hua

    2014-08-01

    Engineering 3D perfusable vascular networks in vitro and reproducing the physiological environment of blood vessels is very challenging for tissue engineering and investigation of blood vessel function. Here, we engineer interconnected 3D microfluidic vascular networks in hydrogels using molded sodium alginate lattice as sacrificial templates. The sacrificial templates are rapidly replicated in polydimethylsiloxane (PDMS) microfluidic chips via Ca⁺²-crosslinking and then fully encapsulated in hydrogels. Interconnected channels with well controlled size and morphology are obtained by dissolving the monolayer or multilayer templates with EDTA solution. The human umbilical vein endothelial cells (HUVECs) are cultured on the channel linings and proliferated to form vascular lumens. The strong cell adhesion capability and adaptive response to shear stress demonstrate the excellent cytocompatibility of both the template and template-sacrificing process. Furthermore, the barrier function of the endothelial layer is characterized and the results show that a confluent endothelial monolayer is fully developed. Taken together, we develop a facile and rapid approach to engineer a vascular model that could be potentially used in physiological studies of vascular functions and vascular tissue engineering. PMID:24887141

  19. Hardware and Software Design of FPGA-based PCIe Gen3 interface for APEnet+ network interconnect system

    NASA Astrophysics Data System (ADS)

    Ammendola, R.; Biagioni, A.; Frezza, O.; Lo Cicero, F.; Lonardo, A.; Martinelli, M.; Paolucci, P. S.; Pastorelli, E.; Rossetti, D.; Simula, F.; Tosoratto, L.; Vicini, P.

    2015-12-01

    In the attempt to develop an interconnection architecture optimized for hybrid HPC systems dedicated to scientific computing, we designed APEnet+, a point-to-point, low-latency and high-performance network controller supporting 6 fully bidirectional off-board links over a 3D torus topology. The first release of APEnet+ (named V4) was a board based on a 40 nm Altera FPGA, integrating 6 channels at 34 Gbps of raw bandwidth per direction and a PCIe Gen2 x8 host interface. It has been the first-of-its-kind device to implement an RDMA protocol to directly read/write data from/to Fermi and Kepler NVIDIA GPUs using NVIDIA peer-to-peer and GPUDirect RDMA protocols, obtaining real zero-copy GPU-to-GPU transfers over the network. The latest generation of APEnet+ systems (now named V5) implements a PCIe Gen3 x8 host interface on a 28 nm Altera Stratix V FPGA, with multi-standard fast transceivers (up to 14.4 Gbps) and an increased amount of configurable internal resources and hardware IP cores to support main interconnection standard protocols. Herein we present the APEnet+ V5 architecture, the status of its hardware and its system software design. Both its Linux Device Driver and the low-level libraries have been redeveloped to support the PCIe Gen3 protocol, introducing optimizations and solutions based on hardware/software co-design.

  20. Electrically Robust Metal Nanowire Network Formation by In-Situ Interconnection with Single-Walled Carbon Nanotubes

    PubMed Central

    Woo, Jong Seok; Han, Joong Tark; Jung, Sunshin; Jang, Jeong In; Kim, Ho Young; Jeong, Hee Jin; Jeong, Seung Yol; Baeg, Kang-Jun; Lee, Geon-Woong

    2014-01-01

    Modulation of the junction resistance between metallic nanowires is a crucial factor for high performance of the network-structured conducting film. Here, we show that under current flow, silver nanowire (AgNW) network films can be stabilised by minimizing the Joule heating at the NW-NW junction assisted by in-situ interconnection with a small amount (less than 3 wt%) of single-walled carbon nanotubes (SWCNTs). This was achieved by direct deposition of AgNW suspension containing SWCNTs functionalised with quadruple hydrogen bonding moieties excluding dispersant molecules. The electrical stabilisation mechanism of AgNW networks involves the modulation of the electrical transportation pathway by the SWCNTs through the SWCNT-AgNW junctions, which results in a relatively lower junction resistance than the NW-NW junction in the network film. In addition, we propose that good contact and Fermi level matching between AgNWs and modified SWCNTs lead to the modulation of the current pathway. The SWCNT-induced stabilisation of the AgNW networks was also demonstrated by irradiating the film with microwaves. The development of the high-throughput fabrication technology provides a robust and scalable strategy for realizing high-performance flexible transparent conductor films. PMID:24763208

  1. Longitudinal Multistage Testing

    ERIC Educational Resources Information Center

    Pohl, Steffi

    2013-01-01

    This article introduces longitudinal multistage testing (lMST), a special form of multistage testing (MST), as a method for adaptive testing in longitudinal large-scale studies. In lMST designs, test forms of different difficulty levels are used, whereas the values on a pretest determine the routing to these test forms. Since lMST allows for…

  2. SnS2 nanoplates embedded in 3D interconnected graphene network as anode material with superior lithium storage performance

    NASA Astrophysics Data System (ADS)

    Tang, Hongli; Qi, Xiang; Han, Weijia; Ren, Long; Liu, Yundan; Wang, Xingyan; Zhong, Jianxin

    2015-11-01

    Three-dimensional (3D) interconnected graphene network embedded with uniformly distributed tin disulfide (SnS2) nanoplates was prepared by a facile two-step method. The microstructures and morphologies of the SnS2/graphene nanocomposite (SSG) are experimentally confirmed by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Using the as-prepared SSG as an anode material for lithium batteries, its electrochemical performances were investigated by cyclic voltammograms (CV), charge/discharge tests, galvanostatic cycling performance and AC impedance spectroscopy. The results demonstrate that the as-prepared SSG exhibits excellent cycling performance with a capacity of 1060 mAh g-1 retained after 200 charge/discharge cycles at a current density of 100 mA g-1, also a superior rate capability of 670 mAh g-1 even at such a high current density of 2000 mA g-1. This favorable performance can be attributed to the unique 3D interconnected architecture with great electro-conductivity and its intimate contact with SnS2. Our results indicate a potential application of this novel 3D SnS2/graphene nanocomposite in lithium-ion battery.

  3. Electrospun interconnected Fe-N/C nanofiber networks as efficient electrocatalysts for oxygen reduction reaction in acidic media.

    PubMed

    Wu, Nan; Wang, Yingde; Lei, Yongpeng; Wang, Bing; Han, Cheng; Gou, Yanzi; Shi, Qi; Fang, Dong

    2015-01-01

    One-dimensional electrospun nanofibers have emerged as a potential candidate for high-performance oxygen reduction reaction (ORR) catalysts. However, contact resistance among the neighbouring nanofibers hinders the electron transport. Here, we report the preparation of interconnected Fe-N/C nanofiber networks (Fe-N/C NNs) with low electrical resistance via electrospinning followed by maturing and pyrolysis. The Fe-N/C NNs show excellent ORR activity with onset and half-wave potential of 55 and 108 mV less than those of Pt/C catalyst in 0.5 M H2SO4. Intriguingly, the resulting Fe-N/C NNs exhibit 34% higher peak current density and superior durability than generic Fe-N/C ones with similar microstructure and chemical compositions. Additionally, it also displays much better durability and methanol tolerance than Pt/C catalyst. The higher electroactivity is mainly due to the more effective electron transport between the interconnected nanofibers. Thus, our findings provide a novel insight into the design of functional electrospun nanofibers for the application in energy storage and conversion fields. PMID:26615799

  4. Electrospun interconnected Fe-N/C nanofiber networks as efficient electrocatalysts for oxygen reduction reaction in acidic media

    PubMed Central

    Wu, Nan; Wang, Yingde; Lei, Yongpeng; Wang, Bing; Han, Cheng; Gou, Yanzi; Shi, Qi; Fang, Dong

    2015-01-01

    One-dimensional electrospun nanofibers have emerged as a potential candidate for high-performance oxygen reduction reaction (ORR) catalysts. However, contact resistance among the neighbouring nanofibers hinders the electron transport. Here, we report the preparation of interconnected Fe-N/C nanofiber networks (Fe-N/C NNs) with low electrical resistance via electrospinning followed by maturing and pyrolysis. The Fe-N/C NNs show excellent ORR activity with onset and half-wave potential of 55 and 108 mV less than those of Pt/C catalyst in 0.5 M H2SO4. Intriguingly, the resulting Fe-N/C NNs exhibit 34% higher peak current density and superior durability than generic Fe-N/C ones with similar microstructure and chemical compositions. Additionally, it also displays much better durability and methanol tolerance than Pt/C catalyst. The higher electroactivity is mainly due to the more effective electron transport between the interconnected nanofibers. Thus, our findings provide a novel insight into the design of functional electrospun nanofibers for the application in energy storage and conversion fields. PMID:26615799

  5. Electrospun interconnected Fe-N/C nanofiber networks as efficient electrocatalysts for oxygen reduction reaction in acidic media

    NASA Astrophysics Data System (ADS)

    Wu, Nan; Wang, Yingde; Lei, Yongpeng; Wang, Bing; Han, Cheng; Gou, Yanzi; Shi, Qi; Fang, Dong

    2015-11-01

    One-dimensional electrospun nanofibers have emerged as a potential candidate for high-performance oxygen reduction reaction (ORR) catalysts. However, contact resistance among the neighbouring nanofibers hinders the electron transport. Here, we report the preparation of interconnected Fe-N/C nanofiber networks (Fe-N/C NNs) with low electrical resistance via electrospinning followed by maturing and pyrolysis. The Fe-N/C NNs show excellent ORR activity with onset and half-wave potential of 55 and 108 mV less than those of Pt/C catalyst in 0.5 M H2SO4. Intriguingly, the resulting Fe-N/C NNs exhibit 34% higher peak current density and superior durability than generic Fe-N/C ones with similar microstructure and chemical compositions. Additionally, it also displays much better durability and methanol tolerance than Pt/C catalyst. The higher electroactivity is mainly due to the more effective electron transport between the interconnected nanofibers. Thus, our findings provide a novel insight into the design of functional electrospun nanofibers for the application in energy storage and conversion fields.

  6. Sustainable Energy Solutions Task 1.0: Networked Monitoring and Control of Small Interconnected Wind Energy Systems

    SciTech Connect

    Janet.twomey@wichita.edu

    2010-04-30

    EXECUTIVE SUMARRY This report presents accomplishments, results, and future work for one task of five in the Wichita State University Sustainable Energy Solutions Project: To develop a scale model laboratory distribution system for research into questions that arise from networked control and monitoring of low-wind energy systems connected to the AC distribution system. The lab models developed under this task are located in the Electric Power Quality Lab in the Engineering Research Building on the Wichita State University campus. The lab system consists of four parts: 1. A doubly-fed induction generator 2. A wind turbine emulator 3. A solar photovoltaic emulator, with battery energy storage 4. Distribution transformers, lines, and other components, and wireless and wired communications and control These lab elements will be interconnected and will function together to form a complete testbed for distributed resource monitoring and control strategies and smart grid applications testing. Development of the lab system will continue beyond this project.

  7. Antimony nanoparticles anchored on interconnected carbon nanofibers networks as advanced anode material for sodium-ion batteries

    NASA Astrophysics Data System (ADS)

    Hou, Hongshuai; Jing, Mingjun; Yang, Yingchang; Zhang, Yan; Song, Weixin; Yang, Xuming; Chen, Jun; Chen, Qiyuan; Ji, Xiaobo

    2015-06-01

    Interconnected carbon nanofibers networks (ICNNs) prepared through the carbonization of polypyrrole (PPy) precursor are utilized as conductive pathways and buffer to improve the Na storage performance of antimony (Sb) as anode for sodium-ion batteries (SIBs). The as-obtained Sb/ICNNs composite exhibits excellent cycle stability. The reversible capacity can remain 542.5 mAh g-1 with a high capacity retention of 96.7% after 100 cycles at a current density of 100 mA g-1. And the superior rate performance is also observed, the reversible capacity can still reach 325 mAh g-1 at a high current density of 3200 mA g-1. These great electrochemical performances observed above suggest that this type of composite can be a nice option for advanced SIBs anode materials and may be extended to other active materials/ICNNs composite electrode.

  8. A proxy design to leverage the interconnection of CoAP Wireless Sensor Networks with Web applications.

    PubMed

    Ludovici, Alessandro; Calveras, Anna

    2015-01-01

    In this paper, we present the design of a Constrained Application Protocol (CoAP) proxy able to interconnect Web applications based on Hypertext Transfer Protocol (HTTP) and WebSocket with CoAP based Wireless Sensor Networks. Sensor networks are commonly used to monitor and control physical objects or environments. Smart Cities represent applications of such a nature. Wireless Sensor Networks gather data from their surroundings and send them to a remote application. This data flow may be short or long lived. The traditional HTTP long-polling used by Web applications may not be adequate in long-term communications. To overcome this problem, we include the WebSocket protocol in the design of the CoAP proxy. We evaluate the performance of the CoAP proxy in terms of latency and memory consumption. The tests consider long and short-lived communications. In both cases, we evaluate the performance obtained by the CoAP proxy according to the use of WebSocket and HTTP long-polling. PMID:25585107

  9. A Proxy Design to Leverage the Interconnection of CoAP Wireless Sensor Networks with Web Applications

    PubMed Central

    Ludovici, Alessandro; Calveras, Anna

    2015-01-01

    In this paper, we present the design of a Constrained Application Protocol (CoAP) proxy able to interconnect Web applications based on Hypertext Transfer Protocol (HTTP) and WebSocket with CoAP based Wireless Sensor Networks. Sensor networks are commonly used to monitor and control physical objects or environments. Smart Cities represent applications of such a nature. Wireless Sensor Networks gather data from their surroundings and send them to a remote application. This data flow may be short or long lived. The traditional HTTP long-polling used by Web applications may not be adequate in long-term communications. To overcome this problem, we include the WebSocket protocol in the design of the CoAP proxy. We evaluate the performance of the CoAP proxy in terms of latency and memory consumption. The tests consider long and short-lived communications. In both cases, we evaluate the performance obtained by the CoAP proxy according to the use of WebSocket and HTTP long-polling. PMID:25585107

  10. Fault tolerant topologies for fiber optic networks and computer interconnects operating in the severe avionics environment

    NASA Astrophysics Data System (ADS)

    Glista, Andrew S., Jr.

    1991-02-01

    The history of fiber optics technology development for naval aircraft is reviewed, and the current status of network and fly-by-light flight control development is examined. Fiber-optic component selection for aircraft is addressed, covering fiber and cables, optical sources, couplers, and connectors. Novel fault-tolerant network topologies for both analog and digital fiber optic transmission, which will permit both packet- and circuit-switched operation of robust fiber optic networks are discussed. The application of smart skin technology, i.e., fibers embedded in composite materials, to optical computer backplanes is briefly considered.

  11. Arabidopsis Ensemble Reverse-Engineered Gene Regulatory Network Discloses Interconnected Transcription Factors in Oxidative Stress[W

    PubMed Central

    Vermeirssen, Vanessa; De Clercq, Inge; Van Parys, Thomas; Van Breusegem, Frank; Van de Peer, Yves

    2014-01-01

    The abiotic stress response in plants is complex and tightly controlled by gene regulation. We present an abiotic stress gene regulatory network of 200,014 interactions for 11,938 target genes by integrating four complementary reverse-engineering solutions through average rank aggregation on an Arabidopsis thaliana microarray expression compendium. This ensemble performed the most robustly in benchmarking and greatly expands upon the availability of interactions currently reported. Besides recovering 1182 known regulatory interactions, cis-regulatory motifs and coherent functionalities of target genes corresponded with the predicted transcription factors. We provide a valuable resource of 572 abiotic stress modules of coregulated genes with functional and regulatory information, from which we deduced functional relationships for 1966 uncharacterized genes and many regulators. Using gain- and loss-of-function mutants of seven transcription factors grown under control and salt stress conditions, we experimentally validated 141 out of 271 predictions (52% precision) for 102 selected genes and mapped 148 additional transcription factor-gene regulatory interactions (49% recall). We identified an intricate core oxidative stress regulatory network where NAC13, NAC053, ERF6, WRKY6, and NAC032 transcription factors interconnect and function in detoxification. Our work shows that ensemble reverse-engineering can generate robust biological hypotheses of gene regulation in a multicellular eukaryote that can be tested by medium-throughput experimental validation. PMID:25549671

  12. Multi-stage complex contagions.

    PubMed

    Melnik, Sergey; Ward, Jonathan A; Gleeson, James P; Porter, Mason A

    2013-03-01

    The spread of ideas across a social network can be studied using complex contagion models, in which agents are activated by contact with multiple activated neighbors. The investigation of complex contagions can provide crucial insights into social influence and behavior-adoption cascades on networks. In this paper, we introduce a model of a multi-stage complex contagion on networks. Agents at different stages-which could, for example, represent differing levels of support for a social movement or differing levels of commitment to a certain product or idea-exert different amounts of influence on their neighbors. We demonstrate that the presence of even one additional stage introduces novel dynamical behavior, including interplay between multiple cascades, which cannot occur in single-stage contagion models. We find that cascades-and hence collective action-can be driven not only by high-stage influencers but also by low-stage influencers. PMID:23556961

  13. Multi-stage complex contagions

    NASA Astrophysics Data System (ADS)

    Melnik, Sergey; Ward, Jonathan A.; Gleeson, James P.; Porter, Mason A.

    2013-03-01

    The spread of ideas across a social network can be studied using complex contagion models, in which agents are activated by contact with multiple activated neighbors. The investigation of complex contagions can provide crucial insights into social influence and behavior-adoption cascades on networks. In this paper, we introduce a model of a multi-stage complex contagion on networks. Agents at different stages—which could, for example, represent differing levels of support for a social movement or differing levels of commitment to a certain product or idea—exert different amounts of influence on their neighbors. We demonstrate that the presence of even one additional stage introduces novel dynamical behavior, including interplay between multiple cascades, which cannot occur in single-stage contagion models. We find that cascades—and hence collective action—can be driven not only by high-stage influencers but also by low-stage influencers.

  14. Performance of a Dynamically Controlled Inverter in a Photovoltaic System Interconnected with a Secondary Network Distribution System

    SciTech Connect

    Coddington, M. H.; Kroposki, B. D.; Basso, T.; Berger, D.; Crowell, K.; Hayes, J.

    2011-01-01

    In 2008, a 300 kW{sub peak} photovoltaic (PV) system was installed on the rooftop of the Colorado Convention Center (CCC). The installation was unique for the electric utility, Xcel Energy, as it had not previously permitted a PV system to be interconnected on a building served by the local secondary network distribution system (network). The PV system was installed with several provisions; one to prevent reverse power flow, another called a dynamically controlled inverter (DCI), that curtails the output of the PV inverters to maintain an amount of load supplied by Xcel Energy at the CCC. The DCI system utilizes current transformers (CTs) to sense power flow to insure that a minimum threshold is maintained from Xcel Energy through the network transformers. The inverters are set to track the load on each of the three phases and curtail power from the PV system when the generated PV system current reaches 95% of the current on any phase. This is achieved by the DCI, which gathers inputs from current transformers measuring the current from the PV array, Xcel, and the spot network load. Preventing reverse power flow is a critical technical requirement for the spot network which serve this part of the CCC. The PV system was designed with the expectation that the DCI system would not curtail the PV system, as the expected minimum load consumption was historically higher than the designed PV system size. However, the DCI system has operated many days during the course of a year, and the performance has been excellent. The DCI system at the CCC was installed as a secondary measure to insure that a minimum level of power flows to the CCC from the Xcel Energy network. While this DCI system was intended for localized control, the system could also reduce output percent if an external smart grid control signal was employed. This paper specifically focuses on the performance of the innovative design at this installation; however, the DCI system could also be used for new s- art

  15. Application of Percolation Theory to Complex Interconnected Networks in Advanced Functional Composites

    NASA Astrophysics Data System (ADS)

    Hing, P.

    2011-11-01

    Percolation theory deals with the behaviour of connected clusters in a system. Originally developed for studying the flow of liquid in a porous body, the percolation theory has been extended to quantum computation and communication, entanglement percolation in quantum networks, cosmology, chaotic situations, properties of disordered solids, pandemics, petroleum industry, finance, control of traffic and so on. In this paper, the application of various models of the percolation theory to predict and explain the properties of a specially developed family of dense sintered and highly refractory Al2O3-W composites for potential application in high intensity discharge light sources such as high pressure sodium lamps and ceramic metal halide lamps are presented and discussed. The low cost, core-shell concept can be extended to develop functional composite materials with unusual dielectric, electrical, magnetic, superconducting, and piezoelectric properties starting from a classical insulator. The core shell concept can also be applied to develop catalysts with high specific surface areas with minimal amount of expensive platinium, palladium or rare earth nano structured materials for light harvesting, replicating natural photosynthesis, in synthetic zeolite composites for the cracking and separation of crude oil. There is also possibility of developing micron and nanosize Faraday cages for quantum devices, nano electronics and spintronics. The possibilities are limitless.

  16. Superior Sodium Storage in 3D Interconnected Nitrogen and Oxygen Dual-Doped Carbon Network.

    PubMed

    Wang, Min; Yang, Zhenzhong; Li, Weihan; Gu, Lin; Yu, Yan

    2016-05-01

    Carbonaceous materials have attracted immense interest as anode materials for Na-ion batteries (NIBs) because of their good chemical, thermal stabilities, as well as high Na-storage capacity. However, the carbonaceous materials as anodes for NIBs still suffer from the lower rate capability and poor cycle life. An N,O-dual doped carbon (denoted as NOC) network is designed and synthesized, which is greatly favorable for sodium storage. It exhibits high specific capacity and ultralong cycling stability, delivering a capacity of 545 mAh g(-1) at 100 mA g(-1) after 100 cycles and retaining a capacity of 240 mAh g(-1) at 2 A g(-1) after 2000 cycles. The NOC composite with 3D well-defined porosity and N,O-dual doped induces active sites, contributing to the enhanced sodium storage. In addition, the NOC is synthesized through a facile solution process, which can be easily extended to the preparation of many other N,O-dual doped carbonaceous materials for wide applications in catalysis, energy storage, and solar cells. PMID:27028729

  17. Open Systems Interconnection.

    ERIC Educational Resources Information Center

    Denenberg, Ray

    1985-01-01

    Discusses the need for standards allowing computer-to-computer communication and gives examples of technical issues. The seven-layer framework of the Open Systems Interconnection (OSI) Reference Model is explained and illustrated. Sidebars feature public data networks and Recommendation X.25, OSI standards, OSI layer functions, and a glossary.…

  18. Performance evaluation of multi-stratum resources integration based on network function virtualization in software defined elastic data center optical interconnect.

    PubMed

    Yang, Hui; Zhang, Jie; Ji, Yuefeng; Tian, Rui; Han, Jianrui; Lee, Young

    2015-11-30

    Data center interconnect with elastic optical network is a promising scenario to meet the high burstiness and high-bandwidth requirements of data center services. In our previous work, we implemented multi-stratum resilience between IP and elastic optical networks that allows to accommodate data center services. In view of this, this study extends to consider the resource integration by breaking the limit of network device, which can enhance the resource utilization. We propose a novel multi-stratum resources integration (MSRI) architecture based on network function virtualization in software defined elastic data center optical interconnect. A resource integrated mapping (RIM) scheme for MSRI is introduced in the proposed architecture. The MSRI can accommodate the data center services with resources integration when the single function or resource is relatively scarce to provision the services, and enhance globally integrated optimization of optical network and application resources. The overall feasibility and efficiency of the proposed architecture are experimentally verified on the control plane of OpenFlow-based enhanced software defined networking (eSDN) testbed. The performance of RIM scheme under heavy traffic load scenario is also quantitatively evaluated based on MSRI architecture in terms of path blocking probability, provisioning latency and resource utilization, compared with other provisioning schemes. PMID:26698748

  19. Committed regional electrical interconnection projects in the Middle East

    SciTech Connect

    Azzam, M.; Al-Said, A.

    1994-12-01

    Due to the well-known advantages of electrical interconnections and their consequent benefits, Jordan considers the interconnection of its electrical network with the neighboring electrical networks as one of its main corporate strategies. At present the electrical interconnection project of the networks of Egypt, Iraq, Jordan, Syria, and Turkey is progressing. To achieve this interconnection project, two feasibility studies were conducted: interconnection of the Egyptian and Jordanian electrical power systems; interconnection of the electrical networks of Egypt, Iraq, Jordan, Syria, and Turkey (EIJST interconnection). This presentation reviews these studies and their results.

  20. The Context of Interconnection for a Nation-Wide Bibliographic Network. Canadian Network Papers, Number 1. Le Contexte de L'Interconnexion dans le Cadre de L'Elaboratim D'Un Reseau Bibliographique National. Documents Sur Les Reseaux Canadiens.

    ERIC Educational Resources Information Center

    Buchinski, Edwin J.; Islam, Mazharul

    The purpose of this document is to highlight the major technical issues of interconnection within a broad based, multi-function, multi-user bibliographic data interchange network in Canada, and to indicate specific areas where development work of a technical nature needs to be undertaken. Recent systems development in the U.S. and Canada is…

  1. 47 CFR 90.477 - Interconnected systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Interconnected systems. 90.477 Section 90.477... MOBILE RADIO SERVICES Transmitter Control Interconnected Systems § 90.477 Interconnected systems. (a... switched telephone network only after modifying their license. See § 1.929 of this chapter. In all cases...

  2. 47 CFR 90.477 - Interconnected systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Interconnected systems. 90.477 Section 90.477... MOBILE RADIO SERVICES Transmitter Control Interconnected Systems § 90.477 Interconnected systems. (a... switched telephone network only after modifying their license. See § 1.929 of this chapter. In all cases...

  3. Multistage Electrophoretic Separators

    NASA Technical Reports Server (NTRS)

    Thomas, Nathan; Doyle, John F.; Kurk, Andy; Vellinger, John C.; Todd, Paul

    2006-01-01

    A multistage electrophoresis apparatus has been invented for use in the separation of cells, protein molecules, and other particles and solutes in concentrated aqueous solutions and suspensions. The design exploits free electrophoresis but overcomes the deficiencies of prior free-electrophoretic separators by incorporating a combination of published advances in mathematical modeling of convection, sedimentation, electro-osmotic flow, and the sedimentation and aggregation of droplets. In comparison with other electrophoretic separators, these apparatuses are easier to use and are better suited to separation in relatively large quantities characterized in the art as preparative (in contradistinction to smaller quantities characterized in the art as analytical). In a multistage electrophoretic separator according to the invention, an applied vertical steady electric field draws the electrically charged particles of interest from within a cuvette to within a collection cavity that has been moved into position of the cuvette. There are multiple collection cavities arranged in a circle; each is aligned with the cuvette for a prescribed short time. The multistage, short-migration-path character of the invention solves, possibly for the first time, the fluid-instability problems associated with free electrophoresis. The figure shows a prototype multistage electrophoretic separator that includes four sample stations and five collection stages per sample. At each sample station, an aqueous solution or suspension containing charged species to be separated is loaded into a cuvette, which is machined into a top plate. The apparatus includes a lower plate, into which 20 collection cavities have been milled. Each cavity is filled with an electrophoresis buffer solution. For the collection of an electrophoretic fraction, the lower plate is rotated to move a designated collection cavity into alignment with the opening of the cuvette. An electric field is then applied between a non

  4. Multistage hierarchy for fast image analysis

    NASA Astrophysics Data System (ADS)

    Grudin, Maxim A.; Harvey, David M.; Timchenko, Leonid I.

    1996-12-01

    In this paper, a novel approach is proposed, which allows for an efficient reduction of the amount of visual data required for representing structural information in the image. This is a multistage architecture which investigates partial correlations between structural image components. Mathematical description of the multistage hierarchical processing is provided, together with the network architecture. Initially the image is partitioned to be processed in parallel channels. In each channel, the structural components are transformed and subsequently separated, depending on their structural significance, to be then combined with the components from other channels for further processing. The output result is represented as a pattern vector, whose components are computed one at a time to allow the quickest possible response. The input gray- scale image is transformed before the processing begins, so that each pixel contains information about the spatial structure of its neighborhood. The most correlated information is extracted first, making the algorithm tolerant to minor structural changes.

  5. Interconnecting heterogeneous database management systems

    NASA Technical Reports Server (NTRS)

    Gligor, V. D.; Luckenbaugh, G. L.

    1984-01-01

    It is pointed out that there is still a great need for the development of improved communication between remote, heterogeneous database management systems (DBMS). Problems regarding the effective communication between distributed DBMSs are primarily related to significant differences between local data managers, local data models and representations, and local transaction managers. A system of interconnected DBMSs which exhibit such differences is called a network of distributed, heterogeneous DBMSs. In order to achieve effective interconnection of remote, heterogeneous DBMSs, the users must have uniform, integrated access to the different DBMs. The present investigation is mainly concerned with an analysis of the existing approaches to interconnecting heterogeneous DBMSs, taking into account four experimental DBMS projects.

  6. Multistage vector (MSV) therapeutics.

    PubMed

    Wolfram, Joy; Shen, Haifa; Ferrari, Mauro

    2015-12-10

    One of the greatest challenges in the field of medicine is obtaining controlled distribution of systemically administered therapeutic agents within the body. Indeed, biological barriers such as physical compartmentalization, pressure gradients, and excretion pathways adversely affect localized delivery of drugs to pathological tissue. The diverse nature of these barriers requires the use of multifunctional drug delivery vehicles that can overcome a wide range of sequential obstacles. In this review, we explore the role of multifunctionality in nanomedicine by primarily focusing on multistage vectors (MSVs). The MSV is an example of a promising therapeutic platform that incorporates several components, including a microparticle, nanoparticles, and small molecules. In particular, these components are activated in a sequential manner in order to successively address transport barriers. PMID:26264836

  7. Electrical interconnect

    DOEpatents

    Frost, John S.; Brandt, Randolph J.; Hebert, Peter; Al Taher, Omar

    2015-10-06

    An interconnect includes a first set of connector pads, a second set of connector pads, and a continuous central portion. A first plurality of legs extends at a first angle from the continuous central portion. Each leg of the first plurality of legs is connected to a connector pad of a first set of connector pads. A second plurality of legs extends at a second angle from the continuous central portion. Each leg of the second plurality of legs is connected to a connector pad of the second set of connector pads. Gaps are defined between legs. The gaps enable movement of the first set of connector pads relative to the second set of connector pads.

  8. The Multistage Compressor Facility

    NASA Technical Reports Server (NTRS)

    Flegel, Ashlie

    2004-01-01

    Research and developments of new aerospace technologies is one of Glenn Research Center's specialties. One facility that deals with the research of aerospace technologies is the High-speed Multistage Compressor Facility. This facility will be testing the performance and efficiency of an Ultra Efficient Engine Technology (UEET) two-stage compressor. There is a lot of preparation involved with testing something of this caliber. Before the test article can be installed into the test rig, the facility must be fully operational and ready to run. Meaning all the necessary instrumentation must be calibrated and installed in the facility. The test rig should also be in safe operating condition, and the proper safety permits obtained. In preparation for the test, the Multistage Compressor Facility went through a few changes. For instance the facility will now be utilizing slip rings, the gearbox went through some maintenance, new lubrications systems replaced the old ones, and special instrumentation needs to be fine tuned to achieve the maximum amount of accurate data. Slips rings help gather information off of a rotating device - in this case from a shaft - onto stationary contacts. The contacts (or brushes) need to be cooled to reduce the amount of frictional heat produced between the slip ring and brushes. The coolant being run through the slip ring is AK-225, a material hazardous to the ozone. To abide by the safety regulations the coolant must be run through a closed chiller system. A new chiller system was purchased but the reservoir that holds the coolant was ventilated which doesn t make the system truly closed and sealed. My task was to design and have a new reservoir built for the chiller system that complies with the safety guidelines. The gearbox had some safety issues also. Located in the back of the gearbox an inching drive was set up. When the inching drive is in use the gears and chain are bare and someone can easily get caught up in it. So to prevent

  9. Advanced Interconnect Development

    SciTech Connect

    Yang, Z.G.; Maupin, G.; Simner, S.; Singh, P.; Stevenson, J.; Xia, G.

    2005-01-27

    The objectives of this project are to develop cost-effective, optimized materials for intermediate temperature SOFC interconnect and interconnect/electrode interface applications and identify and understand degradation processes in interconnects and at their interfaces with electrodes.

  10. Interconnected semiconductor devices

    DOEpatents

    Grimmer, Derrick P.; Paulson, Kenneth R.; Gilbert, James R.

    1990-10-23

    Semiconductor layer and conductive layer formed on a flexible substrate, divided into individual devices and interconnected with one another in series by interconnection layers and penetrating terminals.

  11. Triton-X mediated interconnected nanowalls network of cadmium sulfide thin films via chemical bath deposition and their photoelectrochemical performance

    NASA Astrophysics Data System (ADS)

    Vanalakar, S. A.; Mali, S. S.; Jo, E. A.; Kim, J. Y.; Kim, J. H.; Patil, P. S.

    2014-10-01

    Thin films of cadmium sulfide (CdS) have been wet chemically deposited onto fluorine-doped tin oxide (FTO) coated conducting glass substrates by using non-ionic surfactant; Triton-X 100. An aqueous solution contains cadmium sulphate as a cadmium and thiourea as sulphur precursor. Ammonia used as a complexing agent. The results of measurements of the x-ray diffraction, Raman spectroscopy, optical spectroscopy, energy dispersive spectroscopy, scanning electron microscopy, Brunauer Emmett Teller (BET) surface areas and atomic force microscopy were used for the characterization of the films. These results revealed that the films are polycrystalline, consisting of CdS cubic phase. The films show a direct band gap with energy 2.39 eV. The films show interconnected nanowalls like morphology with well-defined surface area. Finally, the photoelectrochemical (PEC) performance of Triton-X mediated CdS thin film samples were studied. The sample shows photoelectrochemical (PEC) performance with maximum short circuit current density (Jsc) 1.71 mA/cm2 for larger area (1 cm2) solar cells.

  12. 47 CFR 101.519 - Interconnection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SERVICES 24 GHz Service and Digital Electronic Message Service § 101.519 Interconnection. (a) All DEMS licensees must make available to the public all information necessary to allow the manufacture of user... the public all information necessary to allow interconnection of DEMS networks....

  13. 47 CFR 101.519 - Interconnection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SERVICES 24 GHz Service and Digital Electronic Message Service § 101.519 Interconnection. (a) All DEMS licensees must make available to the public all information necessary to allow the manufacture of user... the public all information necessary to allow interconnection of DEMS networks....

  14. Differentiating the functional contributions of resting connectivity networks to memory decision-making: fMRI support for multistage control processes.

    PubMed

    Mill, Ravi D; Cavin, Ian; O'Connor, Akira R

    2015-08-01

    Neural substrates of memory control are engaged when participants encounter unexpected mnemonic stimuli (e.g., a new word when told to expect an old word). The present fMRI study (n = 18) employed the likelihood cueing recognition task to elucidate the role of functional connectivity (fcMRI) networks in supporting memory control processes engaged by these unexpected events. Conventional task-evoked BOLD analyses recovered a memory control network similar to that previously reported, comprising medial prefrontal, lateral prefrontal, and inferior parietal regions. These were split by their differential affiliation to distinct fcMRI networks ("conflict detection" and "confirmatory retrieval" networks). Subsequent ROI analyses clarified the functional significance of this connectivity differentiation, with "conflict" network-affiliated regions specifically sensitive to cue strength, but not to response confidence, and "retrieval" network-affiliated regions showing the opposite pattern. BOLD time course analyses corroborated the segregation of memory control regions into "early" conflict detection and "late" retrieval analysis, with both processes underlying the allocation of memory control. Response specificity and time course findings were generalized beyond task-recruited ROIs to clusters within the large-scale fcMRI networks, suggesting that this connectivity architecture could underlie efficient processing of distinct processes within cognitive tasks. The findings raise important parallels between prevailing theories of memory and cognitive control. PMID:25803597

  15. Microstructure Of Multistage Annealed Nanocrystalline SmCo2Fe2B Alloy With Enhanced Magnetic Properties

    SciTech Connect

    Jiang, Xiujuan; Devaraj, Arun; Balamurugan, B.; Cui, Jun; Shield, Jeffrey E.

    2014-02-11

    The microstructure and chemistry of SmCo2Fe2B melt-spun alloy after multistage annealing was investigated using high resolution transmission electron microscopy (HRTEM) and 3D atom probe tomography. The multistage annealing resulted in an increase in both the coercivity and magnetization. The presence of Sm(Co,Fe)4B (1:4:1) and Sm2(Co,Fe)17Bx (2:17:x) magnetic phases were confirmed using both techniques. Fe2B at a scale of ~ 5 nm was found by HRTEM precipitating within the 1:4:1 phase after the second-stage annealing. Ordering within the 2:17:x phase was directly identified both by the presence of antiphase boundaries observed by TEM and the interconnected isocomposition surface network found in 3D atom probe results in addition to radial distribution function analysis. The variations in the local chemistry after the secondary annealing were considered pivotal in improving the magnetic properties.

  16. Microstructure of multistage annealed nanocrystalline SmCo{sub 2}Fe{sub 2}B alloy with enhanced magnetic properties

    SciTech Connect

    Jiang, Xiujuan Shield, Jeffrey E.; Devaraj, Arun; Balamurugan, B.; Cui, Jun

    2014-02-14

    The microstructure and chemistry of SmCo{sub 2}Fe{sub 2}B melt-spun alloy after multistage annealing was investigated using high resolution transmission electron microscopy (HRTEM) and 3D atom probe tomography. The multistage annealing resulted in an increase in both the coercivity and magnetization. The presence of Sm(Co,Fe){sub 4}B (1:4:1) and Sm{sub 2}(Co,Fe){sub 17}B{sub x} (2:17:x) magnetic phases were confirmed using both techniques. Fe{sub 2}B at a scale of ∼5 nm was found by HRTEM precipitating within the 1:4:1 phase after the second-stage annealing. Ordering within the 2:17:x phase was directly identified both by the presence of antiphase boundaries observed by TEM and the interconnected isocomposition surface network found in 3D atom probe results in addition to radial distribution function analysis. The variations in the local chemistry after the secondary annealing were considered pivotal in improving the magnetic properties.

  17. A sum-over-paths algorithm for third-order impulse-response moment extraction within RC IC-interconnect networks

    NASA Astrophysics Data System (ADS)

    Wojcik, E. A.; Ni, D.; Lam, T. M.; Le Coz, Y. L.

    2015-07-01

    We have created the first stochastic SoP (Sum-over-Paths) algorithm to extract third-order impulse-response (IR) moment within RC IC interconnects. It employs a newly discovered Feynman SoP Postulate. Importantly, our algorithm maintains computational efficiency and full parallelism. Our approach begins with generation of s-domain nodal-voltage equations. We then perform a Taylor-series expansion of the circuit transfer function. These expansions yield transition diagrams involving mathematical coupling constants, or weight factors, in integral powers of complex frequency s. Our SoP Postulate enables stochastic evaluation of path sums within the circuit transition diagram to order s3-corresponding to the order of IR moment (m3) we seek here. We furnish, for the first time, an informal algebraic proof independently validating our SoP Postulate and algorithm. We list, as well, detailed procedural steps, suitable for coding, that define an efficient stochastic algorithm for m3 IR extraction. Origins of the algorithm's statistical "capacitor-number cubed" correction and "double-counting" weight factors are explained, for completeness. Our algorithm was coded and successfully tested against exact analytical solutions for 3-, 5-, and 10-stage RC lines. We achieved better than 0.65% 1-σ error convergence, after only 10K statistical samples, in less than 1 s of 2-GHz Pentium® execution time. These results continue to suggest that stochastic SoP algorithms may find useful application in circuit analysis of massively coupled networks, such as those encountered in high-end digital IC-interconnect CAD.

  18. The brassinosteroid signaling pathway-new key players and interconnections with other signaling networks crucial for plant development and stress tolerance.

    PubMed

    Gruszka, Damian

    2013-01-01

    Brassinosteroids (BRs) are a class of steroid hormones regulating a wide range of physiological processes during the plant life cycle from seed development to the modulation of flowering and senescence. The last decades, and recent years in particular, have witnessed a significant advance in the elucidation of the molecular mechanisms of BR signaling from perception by the transmembrane receptor complex to the regulation of transcription factors influencing expression of the target genes. Application of the new approaches shed light on the molecular functions of the key players regulating the BR signaling cascade and allowed identification of new factors. Recent studies clearly indicated that some of the components of BR signaling pathway act as multifunctional proteins involved in other signaling networks regulating diverse physiological processes, such as photomorphogenesis, cell death control, stomatal development, flowering, plant immunity to pathogens and metabolic responses to stress conditions, including salinity. Regulation of some of these processes is mediated through a crosstalk between BR signalosome and the signaling cascades of other hormones, including auxin, abscisic acid, ethylene and salicylic acid. Unravelling the complicated mechanisms of BR signaling and its interconnections with other molecular networks may be of great importance for future practical applications in agriculture. PMID:23615468

  19. Engineering highly organized and aligned single walled carbon nanotube networks for electronic device applications: Interconnects, chemical sensor, and optoelectronics

    NASA Astrophysics Data System (ADS)

    Kim, Young Lae

    For 20 years, single walled carbon nanotubes (SWNTs) have been studied actively due to their unique one-dimensional nanostructure and superior electrical, thermal, and mechanical properties. For these reasons, they offer the potential to serve as building blocks for future electronic devices such as field effect transistors (FETs), electromechanical devices, and various sensors. In order to realize these applications, it is crucial to develop a simple, scalable, and reliable nanomanufacturing process that controllably places aligned SWNTs in desired locations, orientations, and dimensions. Also electronic properties (semiconducting/metallic) of SWNTs and their organized networks must be controlled for the desired performance of devices and systems. These fundamental challenges are significantly limiting the use of SWNTs for future electronic device applications. Here, we demonstrate a strategy to fabricate highly controlled micro/nanoscale SWNT network structures and present the related assembly mechanism to engineer the SWNT network topology and its electrical transport properties. A method designed to evaluate the electrical reliability of such nano- and microscale SWNT networks is also presented. Moreover, we develop and investigate a robust SWNT based multifunctional selective chemical sensor and a range of multifunctional optoelectronic switches, photo-transistors, optoelectronic logic gates and complex optoelectronic digital circuits.

  20. Polymer TiO2 solar cells: TiO2 interconnected network for improved cell performance

    NASA Astrophysics Data System (ADS)

    Oey, C. C.; Djurisic, A. B.; Wang, H.; Man, K. K. Y.; Chan, W. K.; Xie, M. H.; Leung, Y. H.; Pandey, A.; Nunzi, J.-M.; Chui, P. C.

    2006-02-01

    A titanium dioxide porous network structure was synthesized using a poly(styrene-block-polyethylene oxide) diblock copolymer template. The influence of the titanium precursor concentration and annealing temperature on the obtained morphology was studied. Heterojunction solar cells consisting of TiO2 porous network structure and poly(2-methoxy-5-(2'-ethyl-hexyloxy)-p-phenylene vinylene) (MEH-PPV) were fabricated. The influence of the MEH-PPV layer thickness and device architecture on the solar cell performance was investigated. For an optimized device structure, a short-circuit current as high as 3.3 mA cm-2 is obtained under simulated solar illumination with an air mass AM 1.5 filter. The improved higher short-circuit current compared to other reports on MEH-PPV /TiO2 heterojunction cells can be attributed to improved morphology of the TiO2 layer.

  1. A network model comprising 4 segmental, interconnected ganglia, and its application to simulate multi-legged locomotion in crustaceans.

    PubMed

    Grabowska, M; Toth, T I; Smarandache-Wellmann, C; Daun-Gruhn, S

    2015-06-01

    Inter-segmental coordination is crucial for the locomotion of animals. Arthropods show high variability of leg numbers, from 6 in insects up to 750 legs in millipedes. Despite this fact, the anatomical and functional organization of their nervous systems show basic similarities. The main similarities are the segmental organization, and the way the function of the segmental units is coordinated. We set out to construct a model that could describe locomotion (walking) in animals with more than 6 legs, as well as in 6-legged animals (insects). To this end, we extended a network model by Daun-Gruhn and Tóth (Journal of Computational Neuroscience, doi: 10.1007/s10827-010-0300-1 , 2011). This model describes inter-segmental coordination of the ipsilateral legs in the stick insect during walking. Including an additional segment (local network) into the original model, we could simulate coordination patterns that occur in animals walking on eight legs (e.g., crayfish). We could improve the model by modifying its original cyclic connection topology. In all model variants, the phase relations between the afferent segmental excitatory sensory signals and the oscillatory activity of the segmental networks played a crucial role. Our results stress the importance of this sensory input on the generation of different stable coordination patterns. The simulations confirmed that using the modified connection topology, the flexibility of the model behaviour increased, meaning that changing a single phase parameter, i.e., gating properties of just one afferent sensory signal was sufficient to reproduce all coordination patterns seen in the experiments. PMID:25904469

  2. Multi-stage flash degaser

    DOEpatents

    Rapier, P.M.

    1980-06-26

    A multi-stage flash degaser is incorporated in an energy conversion system having a direct-contact, binary-fluid heat exchanger to remove essentially all of the noncondensable gases from geothermal brine ahead of the direct-contact binary-fluid heat exchanger in order that the heat exchanger and a turbine and condenser of the system can operate at optimal efficiency.

  3. 47 CFR 51.305 - Interconnection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... interface or protocol standards shall constitute evidence of the substantial similarity of network..., interconnection with the incumbent LEC's network: (1) For the transmission and routing of telephone exchange...'s network including, at a minimum: (i) The line-side of a local switch; (ii) The trunk-side of...

  4. 47 CFR 95.1313 - Interconnection prohibited.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... prohibited. MURS stations are prohibited from interconnection with the public switched network... facilities of the public switched telephone network to permit the transmission of messages or signals between points in the wireline or radio network of a public telephone company and persons served by...

  5. Use of transcriptomics and co-expression networks to analyze the interconnections between nitrogen assimilation and photorespiratory metabolism

    PubMed Central

    Pérez-Delgado, Carmen M.; Moyano, Tomás C.; García-Calderón, Margarita; Canales, Javier; Gutiérrez, Rodrigo A.; Márquez, Antonio J.; Betti, Marco

    2016-01-01

    Nitrogen is one of the most important nutrients for plants and, in natural soils, its availability is often a major limiting factor for plant growth. Here we examine the effect of different forms of nitrogen nutrition and of photorespiration on gene expression in the model legume Lotus japonicus with the aim of identifying regulatory candidate genes co-ordinating primary nitrogen assimilation and photorespiration. The transcriptomic changes produced by the use of different nitrogen sources in leaves of L. japonicus plants combined with the transcriptomic changes produced in the same tissue by different photorespiratory conditions were examined. The results obtained provide novel information on the possible role of plastidic glutamine synthetase in the response to different nitrogen sources and in the C/N balance of L. japonicus plants. The use of gene co-expression networks establishes a clear relationship between photorespiration and primary nitrogen assimilation and identifies possible transcription factors connected to the genes of both routes. PMID:27117340

  6. Use of transcriptomics and co-expression networks to analyze the interconnections between nitrogen assimilation and photorespiratory metabolism.

    PubMed

    Pérez-Delgado, Carmen M; Moyano, Tomás C; García-Calderón, Margarita; Canales, Javier; Gutiérrez, Rodrigo A; Márquez, Antonio J; Betti, Marco

    2016-05-01

    Nitrogen is one of the most important nutrients for plants and, in natural soils, its availability is often a major limiting factor for plant growth. Here we examine the effect of different forms of nitrogen nutrition and of photorespiration on gene expression in the model legume Lotus japonicus with the aim of identifying regulatory candidate genes co-ordinating primary nitrogen assimilation and photorespiration. The transcriptomic changes produced by the use of different nitrogen sources in leaves of L. japonicus plants combined with the transcriptomic changes produced in the same tissue by different photorespiratory conditions were examined. The results obtained provide novel information on the possible role of plastidic glutamine synthetase in the response to different nitrogen sources and in the C/N balance of L. japonicus plants. The use of gene co-expression networks establishes a clear relationship between photorespiration and primary nitrogen assimilation and identifies possible transcription factors connected to the genes of both routes. PMID:27117340

  7. Translating the Interconnections between Ecological and Hydrological Processes in a Small Watershed into Process Networks using Information Theory

    NASA Astrophysics Data System (ADS)

    Kim, J.; Woo, N. C.; Kim, S.; Yun, J.; Kim, S.; Kang, M.; Cho, C. H.; Chun, J. H.

    2014-12-01

    We demonstrate how field measurements can inform the selection of model frameworks in small watershed applications. Based on the assumption that ecohydrological systems are open and complex, we employ the process network analysis to identify the system state and the subsystems architecture with changing environment conditions. Ecohydrological and biogeochemical processes in a watershed can be viewed as a network of processes of a wide range of scales involving various feedback loops and time delay. Using the KoFlux tower-based measurements of energy, water and CO2 flux time series along with those representing the soil-plant-atmospheric continuum; we evaluated statistical measures of characterizing the organization of the information flows in the system. We used Shannon's information entropy and calculated the mutual information and transfer entropy, following Ruddell and Kumar (2009). Transfer entropy can measure the relative strength and time scale of couplings between the variables. In this analysis, we selected 15 variables associated with ecohydrological processes, which are groundwater table height, water temperature, specific conductivity, soil moisture contents at three depths, ecosystem respiration, gross primary productivity, sensible heat flux, latent heat flux, precipitation, air temperature, vapor pressure deficit, atmospheric pressure, and solar radiation. The data-driven nature of this investigation may shed a light on reconciling model parsimony with equifinality in small watershed applications. (Acknowledgment: This work and the data used in the study were funded by the Korea Meteorological Administration Research and Development Program under Grant Weather Information Service Engine (WISE) project,153-3100-3133-302-350 and Grant CATER 2014-3030, respectively. The KoFlux site was supported by the Long-term Ecological Study and Monitoring of Forest Ecosystem Project of Korea Forest Research Institute.)

  8. DSS-13 - Using an OSI process control standard for monitor and control. [Deep Space Network experimental station applying Open System interconnection

    NASA Technical Reports Server (NTRS)

    Heuser, W. R.; Chen, Richard L.; Stockett, Michael H.

    1993-01-01

    The flexibility and robustness of a monitor and control (M&C) system are a direct result of the underlying inter-processor communications architecture. A new architecture for M&C at the Deep Space Communications Complexes has been developed based on the manufacturing message specification (MMS) process control standard of the open system interconnection (OSI) suite of protocols. This architecture has been tested both in a laboratory environment and under operational conditions at the Deep Space Network experimental station (DSS-13). The DSS-13 experience in the application of OSI standards to support M&C has been extremely successful. MMS meets the functional needs of the station and provides a level of flexibility and responsiveness previously unknown in that environment. The architecture is robust enough to meet current operational needs and flexible enough to provide a migration path for new subsystems. This paper describes the architecture of the DSS-13 M&C system, discuss how MMS was used and the requirements this imposed on other parts of the system, and provides results from systems and operational testing at DSS-13.

  9. Printed Module Interconnects

    SciTech Connect

    Stockert, Talysa R.; Fields, Jeremy D.; Pach, Gregory F.; Mauger, Scott A.; van Hest, Maikel F. A. M.

    2015-06-14

    Monolithic interconnects in photovoltaic modules connect adjacent cells in series, and are typically formed sequentially involving multiple deposition and scribing steps. Interconnect widths of 500 um every 10 mm result in 5% dead area, which does not contribute to power generation in an interconnected solar panel. This work expands on previous work that introduced an alternative interconnection method capable of producing interconnect widths less than 100 um. The interconnect is added to the module in a single step after deposition of the photovoltaic stack, eliminating the need for scribe alignment. This alternative method can be used for all types of thin film photovoltaic modules. Voltage addition with copper-indium-gallium-diselenide (CIGS) solar cells using a 2-scribe printed interconnect approach is demonstrated. Additionally, interconnect widths of 250 um are shown.

  10. Micro-CT scan reveals an unexpected high-volume and interconnected pore network in a Cretaceous Sanagasta dinosaur eggshell.

    PubMed

    Hechenleitner, E Martín; Grellet-Tinner, Gerald; Foley, Matthew; Fiorelli, Lucas E; Thompson, Michael B

    2016-03-01

    The Cretaceous Sanagasta neosauropod nesting site (La Rioja, Argentina) was the first confirmed instance of extinct dinosaurs using geothermal-generated heat to incubate their eggs. The nesting strategy and hydrothermal activities at this site led to the conclusion that the surprisingly 7 mm thick-shelled eggs were adapted to harsh hydrothermal microenvironments. We used micro-CT scans in this study to obtain the first three-dimensional microcharacterization of these eggshells. Micro-CT-based analyses provide a robust assessment of gas conductance in fossil dinosaur eggshells with complex pore canal systems, allowing calculation, for the first time, of the shell conductance through its thickness. This novel approach suggests that the shell conductance could have risen during incubation to seven times more than previously estimated as the eggshell erodes. In addition, micro-CT observations reveal that the constant widening and branching of pore canals form a complex funnel-like pore canal system. Furthermore, the high density of pore canals and the presence of a lateral canal network in the shell reduce the risks of pore obstruction during the extended incubation of these eggs in a relatively highly humid and muddy nesting environment. PMID:27009182

  11. NiO-Microflower Formed by Nanowire-weaving Nanosheets with Interconnected Ni-network Decoration as Supercapacitor Electrode

    NASA Astrophysics Data System (ADS)

    Ci, Suqing; Wen, Zhenhai; Qian, Yuanyuan; Mao, Shun; Cui, Shumao; Chen, Junhong

    2015-07-01

    We propose a ‘weaving’ evolution mechanism, by systematically investigating the products obtained in controlled experiments, to demonstrate the formation of Ni-based ‘microflowers’ which consists of multiple characteristic dimensions, in which the three dimensional (3D) NiO ‘microflower’ is constructed by a two-dimensional (2D) nanosheet framework that is derived from weaving one-dimensional (1D) nanowires. We found such unique nanostructures are conducive for the generation of an electrically conductive Ni-network on the nanosheet surface after being exposed to a reducing atmosphere. Our study offers a promising strategy to address the intrinsic issue of poor electrical conductivity for NiO-based materials with significant enhancement of utilization of NiO active materials, leading to a remarkable improvement in the performance of the Ni-NiO microflower based supercapacitor. The optimized Ni-NiO microflower material showed a mass specific capacitance of 1,828 F g-1, and an energy density of 15.9 Wh kg-1 at a current density of 0.5 A g-1. This research not only contributes to understanding the formation mechanism of such ‘microflower’ structures but also offers a promising route to advance NiO based supercapacitor given their ease of synthesis, low cost, and long-term stability.

  12. Understand multistage compressor antisurge control

    SciTech Connect

    Rana, S.A.Z.

    1985-03-01

    Methods for, and the principles of antisurge control for multistage centrifugal compressors will be discussed without going into the mathematical details of the theories. Application of these principles is illustrated with an example for a three-stage centrifugal compressor with side suction lines. These principles are not normally discussed in the literature, so this article should be useful to beginners in this field and also serve as a review for more experienced engineers.

  13. Multi-stage flash degaser

    DOEpatents

    Rapier, Pascal M.

    1982-01-01

    A multi-stage flash degaser (18) is incorporated in an energy conversion system (10) having a direct-contact, binary-fluid heat exchanger to remove essentially all of the noncondensable gases from geothermal brine ahead of the direct-contact binary-fluid heat exchanger (22) in order that the heat exchanger (22) and a turbine (48) and condenser (32) of the system (10) can operate at optimal efficiency.

  14. System-theoretical approach to multistage image processing

    NASA Astrophysics Data System (ADS)

    Grudin, Maxim A.; Timchenko, Leonid I.; Harvey, David M.; Gel, Vladimir P.

    1996-08-01

    We present a novel three-dimensional network and its application to pattern analysis. This is a multistage architecture which investigates partial correlations between structural image components. Mathematical description of the multistage hierarchical processing is provided together with the network architecture. Initially the image is partitioned to be processed in parallel channels. In each channel, the structural components are transformed and subsequently separated depending on their informational activity, to be mixed with the components from other channels for further processing. This procedure of temporal decomposition creates a flexible processing hierarchy, which reflects structural image complexity. An output result is represented as a pattern vector, whose components are computed one at a time to allow the quickest possible response. While several applications of the multistage network are possible, this paper represents an algorithm applied to image classification. The input gray-scale image is transformed so that each pixel contains information about the spatial structure of its neighborhood. A three-level representation of gray-scale image is used in order for each pixel to contain the maximum amount of structural information. The investigation of spatial regularities at all hierarchical levels provides a unified approach to pattern analysis. The most correlated information is extracted first, making the algorithm tolerant to minor structural changes.

  15. Perforation patterned electrical interconnects

    SciTech Connect

    Frey, Jonathan

    2014-01-28

    This disclosure describes systems and methods for increasing the usable surface area of electrical contacts within a device, such as a thin film solid state device, through the implementation of electrically conductive interconnects. Embodiments described herein include the use of a plurality of electrically conductive interconnects that penetrate through a top contact layer, through one or more multiple layers, and into a bottom contact layer. The plurality of conductive interconnects may form horizontal and vertical cross-sectional patterns. The use of lasers to form the plurality of electrically conductive interconnects from reflowed layer material further aids in the manufacturing process of a device.

  16. Alignability of Optical Interconnects

    NASA Astrophysics Data System (ADS)

    Beech, Russell Scott

    With the continuing drive towards higher speed, density, and functionality in electronics, electrical interconnects become inadequate. Due to optics' high speed and bandwidth, freedom from capacitive loading effects, and freedom from crosstalk, optical interconnects can meet more stringent interconnect requirements. But, an optical interconnect requires additional components, such as an optical source and detector, lenses, holographic elements, etc. Fabrication and assembly of an optical interconnect requires precise alignment of these components. The successful development and deployment of optical interconnects depend on how easily the interconnect components can be aligned and/or how tolerant the interconnect is to misalignments. In this thesis, a method of quantitatively specifying the relative difficulty of properly aligning an optical interconnect is described. Ways of using this theory of alignment to obtain design and packaging guidelines for optical interconnects are examined. The measure of the ease with which an optical interconnect can be aligned, called the alignability, uses the efficiency of power transfer as a measure of alignment quality. The alignability is related to interconnect package design through the overall cost measure, which depends upon various physical parameters of the interconnect, such as the cost of the components and the time required for fabrication and alignment. Through a mutual dependence on detector size, the relationship between an interconnect's alignability and its bandwidth, signal-to-noise ratio, and bit-error -rate is examined. The results indicate that a range of device sizes exists for which given performance threshold values are satisfied. Next, the alignability of integrated planar-optic backplanes is analyzed in detail. The resulting data show that the alignability can be optimized by varying the substrate thickness or the angle of reflection. By including the effects of crosstalk, in a multi-channel backplane, the

  17. Multilevel codes and multistage decoding

    NASA Astrophysics Data System (ADS)

    Calderbank, A. R.

    1989-03-01

    Imai and Hirakawa have proposed (1977) a multilevel coding method based on binary block codes that admits a staged decoding procedure. Here the coding method is extended to coset codes and it is shown how to calculate minimum squared distance and path multiplicity in terms of the norms and multiplicities of the different cosets. The multilevel structure allows the redundancy in the coset selection procedure to be allocated efficiently among the different levels. It also allows the use of suboptimal multistage decoding procedures that have performance/complexity advantages over maximum-likelihood decoding.

  18. Microstructure of multistage annealed nanocrystalline SmCo2Fe2B alloy with enhanced magnetic properties

    SciTech Connect

    Jiang, Xiujuan; Devaraj, Arun; Balamurugan, B.; Cui, Jun; Shield, Jeffrey E.

    2014-07-30

    The microstructure and chemistry of SmCo2Fe2B melt-spun alloy after multistage annealing was investigated using high resolution transmission electron microscopy (HRTEM) and 3D atom probe tomography. The multistage annealing resulted in an increase in both the coercivity and magnetization. The presence of Sm(Co,Fe)4B (1:4:1) and Sm2(Co,Fe)17Bx (2:17:x) magnetic phases were confirmed using both techniques. Fe2B at a scale of -5 nm was found by HRTEM precipitating within the 1:4:1 phase after the second-stage annealing. Ordering within the 2:17:x phase was directly identified both by the presence of antiphase boundaries observed by TEM and the interconnected isocomposition surface network found in 3D atom probe results in addition to radial distribution function analysis. The variations in the local chemistry after the secondary annealing were considered pivotal in improving the magnetic properties.

  19. Microstructure of Multistage Annealed Nanocrystalline SmCo2Fe2B Alloy with Enhanced Magnetic Properties

    SciTech Connect

    Jiang, Xiujuan; Devaraj, Arun; Balamurugan, B.; Cui, Jun; Shield, Jeffrey E.

    2014-02-01

    The microstructure and chemistry of SmCo2Fe2B melt-spun alloy after multistage annealing was investigated using high resolution transmission electron microscopy (HRTEM) and 3D atom probe tomography. The multistage annealing resulted in an increase in both the coercivity and magnetization. The presence of Sm(Co,Fe)4B (1:4:1) and Sm2(Co,Fe)17Bx (2:17:x) magnetic phases were confirmed using both techniques. Fe2B at a scale of -5 nm was found by HRTEM precipitating within the 1:4:1 phase after the second-stage annealing. Ordering within the 2:17:x phase was directly identified both by the presence of antiphase boundaries observed by TEM and the interconnected isocomposition surface network found in 3D atom probe results in addition to radial distribution function analysis. The variations in the local chemistry after the secondary annealing were considered pivotal in improving the magnetic properties.

  20. Holographic polarization-selective elements in optical network applications

    NASA Astrophysics Data System (ADS)

    Huang, Yang-Tung; Lin, Meng-Fu; Deng, Jiun-Shjou; Fan, Kai-Ting; Chen, Mu-Jung

    1996-09-01

    Highly polarization-selective holographic elements can be achieved with suitable designs. The presented holographic polarization-selective elements are compact and light- weight, and the feature of normally incident and output coupling provide better flexibility and easier alignment for system applications. With suitable designs and arrangements, these elements can be combined to implement star couplers to distribute equal optical power from each input channel to all output channels. In addition, based on our holographic polarization-selective elements with electro-optic halfwave plates, holographic polarization-dependent and polarization- independent optical switches are introduced. The structures to use these switches in various compact 3D multistage interconnection networks for reconfigurable interconnections and in self-healing rings for network service restoration are presented.

  1. Solar cell array interconnects

    DOEpatents

    Carey, P.G.; Thompson, J.B.; Colella, N.J.; Williams, K.A.

    1995-11-14

    Electrical interconnects are disclosed for solar cells or other electronic components using a silver-silicone paste or a lead-tin (Pb-Sn) no-clean fluxless solder cream, whereby the high breakage of thin (<6 mil thick) solar cells using conventional solder interconnect is eliminated. The interconnects of this invention employs copper strips which are secured to the solar cells by a silver-silicone conductive paste which can be used at room temperature, or by a Pb-Sn solder cream which eliminates undesired residue on the active surfaces of the solar cells. Electrical testing using the interconnects of this invention has shown that no degradation of the interconnects developed under high current testing, while providing a very low contact resistance value. 4 figs.

  2. Solar cell array interconnects

    DOEpatents

    Carey, Paul G.; Thompson, Jesse B.; Colella, Nicolas J.; Williams, Kenneth A.

    1995-01-01

    Electrical interconnects for solar cells or other electronic components using a silver-silicone paste or a lead-tin (Pb-Sn) no-clean fluxless solder cream, whereby the high breakage of thin (<6 mil thick) solar cells using conventional solder interconnect is eliminated. The interconnects of this invention employs copper strips which are secured to the solar cells by a silver-silicone conductive paste which can be used at room temperature, or by a Pb-Sn solder cream which eliminates undesired residue on the active surfaces of the solar cells. Electrical testing using the interconnects of this invention has shown that no degradation of the interconnects developed under high current testing, while providing a very low contact resistance value.

  3. Reconfigurable optical interconnections via dynamic computer-generated holograms

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang (Inventor); Zhou, Shaomin (Inventor)

    1994-01-01

    A system is proposed for optically providing one-to-many irregular interconnections, and strength-adjustable many-to-many irregular interconnections which may be provided with strengths (weights) w(sub ij) using multiple laser beams which address multiple holograms and means for combining the beams modified by the holograms to form multiple interconnections, such as a cross-bar switching network. The optical means for interconnection is based on entering a series of complex computer-generated holograms on an electrically addressed spatial light modulator for real-time reconfigurations, thus providing flexibility for interconnection networks for largescale practical use. By employing multiple sources and holograms, the number of interconnection patterns achieved is increased greatly.

  4. Reconfigurable Optical Interconnections Via Dynamic Computer-Generated Holograms

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang (Inventor); Zhou, Shao-Min (Inventor)

    1996-01-01

    A system is presented for optically providing one-to-many irregular interconnections, and strength-adjustable many-to-many irregular interconnections which may be provided with strengths (weights) w(sub ij) using multiple laser beams which address multiple holograms and means for combining the beams modified by the holograms to form multiple interconnections, such as a cross-bar switching network. The optical means for interconnection is based on entering a series of complex computer-generated holograms on an electrically addressed spatial light modulator for real-time reconfigurations, thus providing flexibility for interconnection networks for large-scale practical use. By employing multiple sources and holograms, the number of interconnection patterns achieved is increased greatly.

  5. Micro-fluidic interconnect

    DOEpatents

    Okandan, Murat; Galambos, Paul C.; Benavides, Gilbert L.; Hetherington, Dale L.

    2006-02-28

    An apparatus for simultaneously aligning and interconnecting microfluidic ports is presented. Such interconnections are required to utilize microfluidic devices fabricated in Micro-Electromechanical-Systems (MEMS) technologies, that have multiple fluidic access ports (e.g. 100 micron diameter) within a small footprint, (e.g. 3 mm.times.6 mm). Fanout of the small ports of a microfluidic device to a larger diameter (e.g. 500 microns) facilitates packaging and interconnection of the microfluidic device to printed wiring boards, electronics packages, fluidic manifolds etc.

  6. Application of optical interconnect technology at Lawrence Livermore National Laboratory

    SciTech Connect

    Haigh, R.E.; Lowry, M.E.; McCammon, K.; Hills, R.; Mitchell, R.; Sweider, D.

    1995-08-10

    Optical interconnects will be required to meet the information bandwidth requirements of future communication and computing applications. At Lawrence Livermore National Laboratory, the authors are involved in applying optical interconnect technologies in two distinct application areas: Multi-Gigabit/sec Computer Backplanes and Gigabit/sec Wide Area Networking using Wavelength Division Multiplexing. In this paper, the authors discuss their efforts to integrate optical interconnect technologies into prototype computing and communication systems.

  7. LTCC interconnects in microsystems

    NASA Astrophysics Data System (ADS)

    Rusu, Cristina; Persson, Katrin; Ottosson, Britta; Billger, Dag

    2006-06-01

    Different microelectromechanical system (MEMS) packaging strategies towards high packaging density of MEMS devices and lower expenditure exist both in the market and in research. For example, electrical interconnections and low stress wafer level packaging are essential for improving device performance. Hybrid integration of low temperature co-fired ceramics (LTCC) with Si can be a way for an easier packaging system with integrated electrical interconnection, and as well towards lower costs. Our research on LTCC-Si integration is reported in this paper.

  8. Zee electrical interconnect

    NASA Technical Reports Server (NTRS)

    Rust, Thomas M. (Inventor); Gaddy, Edward M. (Inventor); Herriage, Michael J. (Inventor); Patterson, Robert E. (Inventor); Partin, Richard D. (Inventor)

    2001-01-01

    An interconnect, having some length, that reliably connects two conductors separated by the length of the interconnect when the connection is made but in which one length if unstressed would change relative to the other in operation. The interconnect comprises a base element an intermediate element and a top element. Each element is rectangular and formed of a conducting material and has opposed ends. The elements are arranged in a generally Z-shape with the base element having one end adapted to be connected to one conductor. The top element has one end adapted to be connected to another conductor and the intermediate element has its ends disposed against the other end of the base and the top element. Brazes mechanically and electrically interconnect the intermediate element to the base and the top elements proximate the corresponding ends of the elements. When the respective ends of the base and the top elements are connected to the conductors, an electrical connection is formed therebetween, and when the conductors are relatively moved or the interconnect elements change length the elements accommodate the changes and the associated compression and tension forces in such a way that the interconnect does not mechanically fatigue.

  9. Research Resource: dkCOIN, the National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK) Consortium Interconnectivity Network: A Pilot Program to Aggregate Research Resources Generated by Multiple Research Consortia

    PubMed Central

    McKenna, Neil J.; Howard, Christopher L.; Aufiero, Michael; Easton-Marks, Jeremy; Steffen, David L.; Becnel, Lauren B.; Magnuson, Mark A.; McIndoe, Richard A.

    2012-01-01

    The National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK) supports multiple basic science consortia that generate high-content datasets, reagent resources, and methodologies, in the fields of kidney, urology, hematology, digestive, and endocrine diseases, as well as metabolic diseases such as diabetes and obesity. These currently include the Beta Cell Biology Consortium, the Nuclear Receptor Signaling Atlas, the Diabetic Complications Consortium, and the Mouse Metabolic Phenotyping Centers. Recognizing the synergy that would accrue from aggregating information generated and curated by these initiatives in a contiguous informatics network, we created the NIDDK Consortium Interconnectivity Network (dkCOIN; www.dkcoin.org). The goal of this pilot project, organized by the NIDDK, was to establish a single point of access to a toolkit of interconnected resources (datasets, reagents, and protocols) generated from individual consortia that could be readily accessed by biologists of diverse backgrounds and research interests. During the pilot phase of this activity dkCOIN collected nearly 2000 consortium-curated resources, including datasets (functional genomics) and reagents (mouse strains, antibodies, and adenoviral constructs) and built nearly 3000 resource-to-resource connections, thereby demonstrating the feasibility of further extending this database in the future. Thus, dkCOIN promises to be a useful informatics solution for rapidly identifying useful resources generated by participating research consortia. PMID:22734043

  10. Architecture for on-die interconnect

    DOEpatents

    Khare, Surhud; More, Ankit; Somasekhar, Dinesh; Dunning, David S.

    2016-03-15

    In an embodiment, an apparatus includes: a plurality of islands configured on a semiconductor die, each of the plurality of islands having a plurality of cores; and a plurality of network switches configured on the semiconductor die and each associated with one of the plurality of islands, where each network switch includes a plurality of output ports, a first set of the output ports are each to couple to the associated network switch of an island via a point-to-point interconnect and a second set of the output ports are each to couple to the associated network switches of a plurality of islands via a point-to-multipoint interconnect. Other embodiments are described and claimed.

  11. Multistage Simulations of the GE90 Turbine

    NASA Technical Reports Server (NTRS)

    Turner, Mark G.; Vitt, Paul H.; Topp, David A.; Saeidi, Sohrab; Hunter, Scott D.; Dailey, Lyle D.; Beach, Timothy A.

    1999-01-01

    The average passage approach has been used to analyze three multistage configurations of the GE90 turbine. These are a high pressure turbine rig, a low pressure turbine rig and a full turbine configuration comprising 18 blade rows of the GE90 engine at takeoff conditions. Cooling flows in the high pressure turbine have been simulated using source terms. This is the first time a dual-spool cooled turbine has been analyzed in 3D using a multistage approach. There is good agreement between the simulations and experimental results. Multistage and component interaction effects are also presented. The parallel efficiency of the code is excellent at 87.3% using 121 processors on an SGI Origin for the 18 blade row configuration. The accuracy and efficiency of the calculation now allow it to be effectively used in a design environment so that multistage effects can be accounted for in turbine design.

  12. Folded fibre bus interconnects with distributed amplification

    NASA Astrophysics Data System (ADS)

    Lorenzo, Raul Hernandez; Urquhart, Paul; Lopez-Amo, Manuel

    1998-06-01

    An optical fibre network for application as an interconnect within major nodes is investigated theoretically. The network is configured as a folded bus in which the spine consists of erbium doped fibre to overcome the power division at the couplers. It is argued that high received powers with a narrow dynamic range can be obtained simultaneously with bit rates in the order of 10 Gbit/s and bit error rates of 10 -12 or less.

  13. Combustor with multistage internal vortices

    DOEpatents

    Shang, Jer Y.; Harrington, Richard E.

    1989-01-01

    A fluidized bed combustor is provided with a multistage arrangement of vortex generators in the freeboard area. The vortex generators are provided by nozzle means which extend into the interior of the freeboard for forming vortices within the freeboard area to enhance the combustion of particulate material entrained in product gases ascending into the freeboard from the fluidized bed. Each of the nozzles are radially inwardly spaced from the combustor walls defining the freeboard to provide for the formation of an essentially vortex-free, vertically extending annulus about the vortices whereby the particulate material centrifuged from the vortices against the inner walls of the combustor is returned through the annulus to the fluidized bed. By adjusting the vortex pattern within the freeboard, a significant portion of the full cross-sectional area of the freeboard except for the peripheral annulus can be contacted with the turbulent vortical flow for removing the particulate material from the gaseous products and also for enhancing the combustion thereof within the freeboard.

  14. Combustor with multistage internal vortices

    DOEpatents

    Shang, Jer Yu; Harrington, R.E.

    1987-05-01

    A fluidized bed combustor is provided with a multistage arrangement of vortex generators in the freeboard area. The vortex generators are provided by nozzle means which extend into the interior of the freeboard for forming vortices within the freeboard areas to enhance the combustion of particulate material entrained in product gases ascending into the freeboard from the fluidized bed. Each of the nozzles are radially inwardly spaced from the combustor walls defining the freeboard to provide for the formation of an essentially vortex-free, vertically extending annulus about the vortices whereby the particulate material centrifuged from the vortices against the inner walls of the combustor is returned through the annulus to the fluidized bed. By adjusting the vortex pattern within the freeboard, a significant portion of the full cross-sectional area of the freeboard except for the peripheral annulus can be contacted with the turbulent vortical flow for removing the particulate material from the gaseous products and also for enhancing the combustion thereof within the freeboard. 2 figs.

  15. SOFC INTERCONNECT DEVELOPMENT

    SciTech Connect

    Diane M. England

    2004-03-16

    An interconnect for an SOFC stack is used to connect fuel cells into a stack. SOFC stacks are expected to run for 40,000 hours and 10 thermal cycles for the stationary application and 10,000 hours and 7000 thermal cycles for the transportation application. The interconnect of a stack must be economical and robust enough to survive the SOFC stack operation temperature of 750 C and must maintain the electrical connection to the fuel cells throughout the lifetime and under thermal cycling conditions. Ferritic and austenitic stainless steels, and nickel-based superalloys were investigated as possible interconnect materials for solid oxide fuel cell (SOFC) stacks. The alloys were thermally cycled in air and in a wet nitrogen-argon-hydrogen (N2-Ar-H2-H2O) atmosphere. Thermogravimetry was used to determine the parabolic oxidation rate constants of the alloys in both atmospheres. The area-specific resistance of the oxide scale and metal substrates were measured using a two-probe technique with platinum contacts. The study identifies two new interconnect designs which can be used with both bonded and compressive stack sealing mechanisms. The new interconnect designs offer a solution to chromium vaporization, which can lead to degradation of some (chromium-sensitive) SOFC cathodes.

  16. Optically interconnected phased arrays

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul B.; Kunath, Richard R.

    1988-01-01

    Phased-array antennas are required for many future NASA missions. They will provide agile electronic beam forming for communications and tracking in the range of 1 to 100 GHz. Such phased arrays are expected to use several hundred GaAs monolithic integrated circuits (MMICs) as transmitting and receiving elements. However, the interconnections of these elements by conventional coaxial cables and waveguides add weight, reduce flexibility, and increase electrical interference. Alternative interconnections based on optical fibers, optical processing, and holography are under evaluation as possible solutions. In this paper, the current status of these techniques is described. Since high-frequency optical components such as photodetectors, lasers, and modulators are key elements in these interconnections, their performance and limitations are discussed.

  17. SOFC INTERCONNECT DEVELOPMENT

    SciTech Connect

    Diane M. England

    2003-06-06

    This report summarizes the interconnect work being performed at Delphi. Materials were chosen for this interconnect project were chosen from ferritic and austenitic stainless steels, and nickel-based superalloys. The alloys are thermally cycled in air and a wet hydrogen atmosphere. The oxide scale adherence, electrical resistance and oxidation resistance are determined after long-term oxidation of each alloy. The oxide scale adherence will be observed using a scanning electron microscope. The electrical resistance of the oxidized alloys will be determined using an electrical resistance measurement apparatus which has been designed and is currently being built. Data from the electrical resistance measurement is expected to be provided in the second quarter.

  18. Central American electrical interconnection

    SciTech Connect

    Not Available

    1988-12-01

    A technical cooperation grant of $2.25 million, designed to strengthen the capacity of Central American countries to operate their regional interconnected electrical system, was announced by the Inter-American Development Bank (IDB). The grant, extended from the banks Fund for Special Operations, will help improve the capacity of the regions electric power companies to achieve economical, safe operation of the interconnected electric power systems. The funds will also be used to finance regional studies of the accords, procedures, regulations, and supervisory mechanisms for the system, as well as program development and data bases.

  19. Nanotrench for nano and microparticle electrical interconnects

    NASA Astrophysics Data System (ADS)

    Dayen, J.-F.; Faramarzi, V.; Pauly, M.; Kemp, N. T.; Barbero, M.; Pichon, B. P.; Majjad, H.; Begin-Colin, S.; Doudin, B.

    2010-08-01

    We present a simple and versatile patterning procedure for the reliable and reproducible fabrication of high aspect ratio (104) electrical interconnects that have separation distances down to 20 nm and lengths of several hundreds of microns. The process uses standard optical lithography techniques and allows parallel processing of many junctions, making it easily scalable and industrially relevant. We demonstrate the suitability of these nanotrenches as electrical interconnects for addressing micro and nanoparticles by realizing several circuits with integrated species. Furthermore, low impedance metal-metal low contacts are shown to be obtained when trapping a single metal-coated microsphere in the gap, emphasizing the intrinsic good electrical conductivity of the interconnects, even though a wet process is used. Highly resistive magnetite-based nanoparticles networks also demonstrate the advantage of the high aspect ratio of the nanotrenches for providing access to electrical properties of highly resistive materials, with leakage current levels below 1 pA.

  20. Interconnecting with VIPs

    ERIC Educational Resources Information Center

    Collins, Robert

    2013-01-01

    Interconnectedness changes lives. It can even save lives. Recently the author got to witness and be part of something in his role as a teacher of primary science that has changed lives: it may even have saved lives. It involved primary science teaching--and the climate. Robert Collins describes how it is all interconnected. The "Toilet…

  1. Capillary interconnect device

    SciTech Connect

    Renzi, Ronald F

    2013-11-19

    An interconnecting device for connecting a plurality of first fluid-bearing conduits to a corresponding plurality of second fluid-bearing conduits thereby providing fluid communication between the first fluid-bearing conduits and the second fluid-bearing conduits. The device includes a manifold and one or two ferrule plates that are held by compressive axial forces.

  2. Anodization control for barrier-oxide thinning and 3D interconnected pores and direct electrodeposition of nanowire networks on native aluminium substrates.

    PubMed

    Gillette, Eleanor; Wittenberg, Stefanie; Graham, Lauren; Lee, Kwijong; Rubloff, Gary; Banerjee, Parag; Lee, Sang Bok

    2015-02-01

    Here we report a strategy for combining techniques for pore branching and barrier layer thinning to produce 3D porous anodized aluminum oxide films with direct ohmic contact to the native aluminum. This method provides an example of a rationally designed template which need not be removed from the aluminum, but which is also not constrained to traditional 2D pore geometry. We first demonstrate the barrier layer removal and pore branching techniques independently, and then combine them to produce free standing arrays of interconnected Ni nanostructures. Nickel nanostructures are deposited directly onto the aluminum to demonstrate the success of the structural modification, and showcase the potential for these films to be used as templates. This approach is the first to demonstrate the design and execution of multiple pore modification techniques in the same membrane, and demonstrates the first directly deposited 3D structures on aluminum substrates. PMID:25562070

  3. Psychoactive pharmaceuticals as environmental contaminants may disrupt highly inter-connected nodes in an Autism-associated protein-protein interaction network

    PubMed Central

    2015-01-01

    Background Most cases of idiopathic autism spectrum disorder (ASD) likely result from unknown environmental triggers in genetically susceptible individuals. These triggers may include maternal exposure of a fetus to minute concentrations of pharmaceuticals, such as carbamazepine (CBZ), venlafaxine (VNX) and fluoxetine (FLX). Unmetabolized pharmaceuticals reach drinking water through a variety of routes, including ineffectively treated sewage. Previous studies in our laboratory examined the extent to which gene sets were enriched in minnow brains treated with pharmaceuticals. Here, we tested the hypothesis that genes in fish brains and human cell cultures, significantly enriched by pharmaceuticals, would have distinct characteristics in an ASD-associated protein interaction network. We accomplished this by comparing these groups using 10 network indices. Results A network of 7212 proteins and 33,461 interactions was generated. We found that network characteristics for enriched gene sets for particular pharmaceuticals were distinct from each other, and were different from non-enriched ASD gene sets. In particular, genes in fish brains, enriched by CBZ and VNX 1) had higher network importance than that in the overall network, and those enriched by FLX, and 2) were distinct from FLX and non-enriched ASD genes in multivariate network space. Similarly, genes in human cell cultures enriched by pharmaceutical mixtures (at environmental concentrations) and valproate (at clinical dosages) had similar network signatures, and had greater network importance than genes in the overall ASD network. Conclusions The results indicate that important gene sets in the ASD network are particularly susceptible to perturbation by pharmaceuticals at environmental concentrations. PMID:25952302

  4. Multi-megavolt low jitter multistage switch

    DOEpatents

    Humphreys, D.R.; Penn, K.J. Jr.

    1985-06-19

    It is one object of the present invention to provide a multistage switch capable of holding off numerous megavolts, until triggered, from a particle beam accelerator of the type used for inertial confinement fusion. The invention provides a multistage switch having low timing jitter and capable of producing multiple spark channels for spreading current over a wider area to reduce electrode damage and increase switch lifetime. The switch has fairly uniform electric fields and a short spark gap for laser triggering and is engineered to prevent insulator breakdowns.

  5. Mars integrated transportation system multistage Mars mission

    NASA Technical Reports Server (NTRS)

    1991-01-01

    In accordance with the objective of the Mars Integrated Transport System (MITS) program, the Multistage Mars Mission (MSMM) design team developed a profile for a manned mission to Mars. The purpose of the multistage mission is to send a crew of five astronauts to the martian surface by the year 2019. The mission continues man's eternal quest for exploration of new frontiers. This mission has a scheduled duration of 426 days that includes experimentation en route as well as surface exploration and experimentation. The MSMM is also designed as a foundation for a continuing program leading to the colonization of the planet Mars.

  6. Multi-stage separations based on dielectrophoresis

    DOEpatents

    Mariella, Jr., Raymond P.

    2004-07-13

    A system utilizing multi-stage traps based on dielectrophoresis. Traps with electrodes arranged transverse to the flow and traps with electrodes arranged parallel to the flow with combinations of direct current and alternating voltage are used to trap, concentrate, separate, and/or purify target particles.

  7. Phase stability in a multistage Zeeman decelerator

    SciTech Connect

    Wiederkehr, A. W.; Hogan, S. D.; Merkt, F.

    2010-10-15

    The phase stability of a multistage Zeeman decelerator is analyzed by numerical particle-trajectory simulations and experimental measurements. A one-dimensional model of the phase stability in multistage Stark deceleration [Bethlem et al., Phys. Rev. Lett. 84, 5744 (2000)] has been adapted to multistage Zeeman deceleration and compared with one- and three-dimensional particle-trajectory simulations, including the analysis of the effect of finite switch-on and -off times of the deceleration pulses. The comparison reveals that transverse effects in the decelerator lead to a considerable reduction of the phase-space acceptance at low values of the phase angle and an enhancement at high values. The optimal combinations of phase angles and currents with which a preset amount of kinetic energy can be removed from atoms and molecules in a pulsed supersonic beam using a multistage decelerator are determined by simulation. Quantitative analysis of the phase-space acceptance within a given volume reveals that for our decelerator (8 {mu}s switch-off time) optimal conditions are achieved for values of the phase angle between 45 deg. and 55 deg. This conclusion is examined and confirmed by experimental measurements using deuterium atoms. Alternative approaches to generate optimal deceleration pulse sequences, such as the implementation of evolutionary algorithms or the use of higher-order modes of the decelerator, are discussed.

  8. Phase stability in a multistage Zeeman decelerator

    NASA Astrophysics Data System (ADS)

    Wiederkehr, A. W.; Hogan, S. D.; Merkt, F.

    2010-10-01

    The phase stability of a multistage Zeeman decelerator is analyzed by numerical particle-trajectory simulations and experimental measurements. A one-dimensional model of the phase stability in multistage Stark deceleration [Bethlem , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.84.5744 84, 5744 (2000)] has been adapted to multistage Zeeman deceleration and compared with one- and three-dimensional particle-trajectory simulations, including the analysis of the effect of finite switch-on and -off times of the deceleration pulses. The comparison reveals that transverse effects in the decelerator lead to a considerable reduction of the phase-space acceptance at low values of the phase angle and an enhancement at high values. The optimal combinations of phase angles and currents with which a preset amount of kinetic energy can be removed from atoms and molecules in a pulsed supersonic beam using a multistage decelerator are determined by simulation. Quantitative analysis of the phase-space acceptance within a given volume reveals that for our decelerator (8 μs switch-off time) optimal conditions are achieved for values of the phase angle between 45° and 55°. This conclusion is examined and confirmed by experimental measurements using deuterium atoms. Alternative approaches to generate optimal deceleration pulse sequences, such as the implementation of evolutionary algorithms or the use of higher-order modes of the decelerator, are discussed.

  9. Automated Simultaneous Assembly for Multistage Testing

    ERIC Educational Resources Information Center

    Breithaupt, Krista; Ariel, Adelaide; Veldkamp, Bernard P.

    2005-01-01

    This article offers some solutions used in the assembly of the computerized Uniform Certified Public Accountancy (CPA) licensing examination as practical alternatives for operational programs producing large numbers of forms. The Uniform CPA examination was offered as an adaptive multistage test (MST) beginning in April of 2004. Examples of…

  10. "MSTGen": Simulated Data Generator for Multistage Testing

    ERIC Educational Resources Information Center

    Han, Kyung T.

    2013-01-01

    Multistage testing, or MST, was developed as an alternative to computerized adaptive testing (CAT) for applications in which it is preferable to administer a test at the level of item sets (i.e., modules). As with CAT, the simulation technique in MST plays a critical role in the development and maintenance of tests. "MSTGen," a new MST…

  11. A Multistage Approach for Image Registration.

    PubMed

    Bowen, Francis; Hu, Jianghai; Du, Eliza Yingzi

    2016-09-01

    Successful image registration is an important step for object recognition, target detection, remote sensing, multimodal content fusion, scene blending, and disaster assessment and management. The geometric and photometric variations between images adversely affect the ability for an algorithm to estimate the transformation parameters that relate the two images. Local deformations, lighting conditions, object obstructions, and perspective differences all contribute to the challenges faced by traditional registration techniques. In this paper, a novel multistage registration approach is proposed that is resilient to view point differences, image content variations, and lighting conditions. Robust registration is realized through the utilization of a novel region descriptor which couples with the spatial and texture characteristics of invariant feature points. The proposed region descriptor is exploited in a multistage approach. A multistage process allows the utilization of the graph-based descriptor in many scenarios thus allowing the algorithm to be applied to a broader set of images. Each successive stage of the registration technique is evaluated through an effective similarity metric which determines subsequent action. The registration of aerial and street view images from pre- and post-disaster provide strong evidence that the proposed method estimates more accurate global transformation parameters than traditional feature-based methods. Experimental results show the robustness and accuracy of the proposed multistage image registration methodology. PMID:26292357

  12. Visualizing interconnections among climate risks

    NASA Astrophysics Data System (ADS)

    Tanaka, K.; Yokohata, T.; Nishina, K.; Takahashi, K.; Emori, S.; Kiguchi, M.; Iseri, Y.; Honda, Y.; Okada, M.; Masaki, Y.; Yamamoto, A.; Shigemitsu, M.; Yoshimori, M.; Sueyoshi, T.; Hanasaki, N.; Ito, A.; Sakurai, G.; Iizumi, T.; Nishimori, M.; Lim, W. H.; Miyazaki, C.; Kanae, S.; Oki, T.

    2015-12-01

    It is now widely recognized that climate change is affecting various sectors of the world. Climate change impact on one sector may spread out to other sectors including those seemingly remote, which we call "interconnections of climate risks". While a number of climate risks have been identified in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5), there has been no attempt to explore their interconnections comprehensively. Here we present a first and most exhaustive visualization of climate risks drawn based on a systematic literature survey. Our risk network diagrams depict that changes in the climate system impact natural capitals (terrestrial water, crop, and agricultural land) as well as social infrastructures, influencing the socio-economic system and ultimately our access to food, water, and energy. Our findings suggest the importance of incorporating climate risk interconnections into impact and vulnerability assessments and call into question the widely used damage function approaches, which address a limited number of climate change impacts in isolation. Furthermore, the diagram is useful to educate decision makers, stakeholders, and general public about cascading risks that can be triggered by the climate change. Socio-economic activities today are becoming increasingly more inter-dependent because of the rapid technological progress, urbanization, and the globalization among others. Equally complex is the ecosystem that is susceptible to climate change, which comprises interwoven processes affecting one another. In the context of climate change, a number of climate risks have been identified and classified according to regions and sectors. These reports, however, did not fully address the inter-relations among risks because of the complexity inherent in this issue. Climate risks may ripple through sectors in the present inter-dependent world, posing a challenge ahead of us to maintain the resilience of the system. It is

  13. The Strength of the Spatially Interconnected Eutectic Network in HPDC Mg-La, Mg-Nd, and Mg-La-Nd Alloys

    NASA Astrophysics Data System (ADS)

    Zhang, Bao; Gavras, Serge; Nagasekhar, Anumalasetty V.; Cáceres, Carlos Horacio; Easton, Mark A.

    2014-09-01

    3D numerical images of the intergranular percolating eutectic of two binary alloys, Mg-0.62 at. pctLa and Mg-0.60 at. pctNd, created using dual beam FIB tomography, were incorporated into an FEM code to model their tensile behavior. Due to its high volume fraction (29.9 pct), the behavior of the Mg-La network was akin to that of a stretch-dominated micro-truss structure, whereas the Mg-Nd's, with a relatively low volume fraction (7.5 pct), mimicked that of a bending-dominated structure. The 3D network contributed some 37 MPa to the strength of the Mg-La alloy casting, whereas it only added about 1.4 MPa to the Mg-Nd's. The model predictions based on the binary alloys were verified using cast-to-shape specimens of the Mg-La and two ternary Mg-La-Nd alloys, subjected to a flash-annealing aiming at breaking up the continuity of the 3D network, while preserving the rest of the microstructure unchanged. The flash-annealed specimens exhibited a decrease in strength that matched closely the computed values. Implications regarding alloy design involving the eutectic network and solid solution hardening of more complex alloys are discussed.

  14. Local network interconnection through a satellite point-to-multipoint link. Ph.D. Thesis - Ecole Nationale Superieure des Telecommunications, 6 Jul. 1985

    NASA Technical Reports Server (NTRS)

    Duarte, O. Muniz Bandeira

    1986-01-01

    Four architectures to implement a point to multipoint satellite link protocol for communication services offered by the Telecom 1 satellite network are presented. A safe communication service with error correction and flow control facilities is described. It is shown that a time transparent communication system combines simplicity and cost advantages.

  15. Multi-Stage System for Automatic Target Recognition

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Lu, Thomas T.; Ye, David; Edens, Weston; Johnson, Oliver

    2010-01-01

    A multi-stage automated target recognition (ATR) system has been designed to perform computer vision tasks with adequate proficiency in mimicking human vision. The system is able to detect, identify, and track targets of interest. Potential regions of interest (ROIs) are first identified by the detection stage using an Optimum Trade-off Maximum Average Correlation Height (OT-MACH) filter combined with a wavelet transform. False positives are then eliminated by the verification stage using feature extraction methods in conjunction with neural networks. Feature extraction transforms the ROIs using filtering and binning algorithms to create feature vectors. A feedforward back-propagation neural network (NN) is then trained to classify each feature vector and to remove false positives. The system parameter optimizations process has been developed to adapt to various targets and datasets. The objective was to design an efficient computer vision system that can learn to detect multiple targets in large images with unknown backgrounds. Because the target size is small relative to the image size in this problem, there are many regions of the image that could potentially contain the target. A cursory analysis of every region can be computationally efficient, but may yield too many false positives. On the other hand, a detailed analysis of every region can yield better results, but may be computationally inefficient. The multi-stage ATR system was designed to achieve an optimal balance between accuracy and computational efficiency by incorporating both models. The detection stage first identifies potential ROIs where the target may be present by performing a fast Fourier domain OT-MACH filter-based correlation. Because threshold for this stage is chosen with the goal of detecting all true positives, a number of false positives are also detected as ROIs. The verification stage then transforms the regions of interest into feature space, and eliminates false positives using an

  16. Carbon Nanotube Interconnect

    NASA Technical Reports Server (NTRS)

    Li, Jun (Inventor); Meyyappan, Meyya (Inventor)

    2006-01-01

    Method and system for fabricating an electrical interconnect capable of supporting very high current densities ( 10(exp 6)-10(exp 10) Amps/sq cm), using an array of one or more carbon nanotubes (CNTs). The CNT array is grown in a selected spaced apart pattern, preferably with multi-wall CNTs, and a selected insulating material, such as SiOw, or SiuNv is deposited using CVD to encapsulate each CNT in the array. An exposed surface of the insulating material is planarized to provide one or more exposed electrical contacts for one or more CNTs.

  17. Optical Interconnection Via Computer-Generated Holograms

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang; Zhou, Shaomin

    1995-01-01

    Method of free-space optical interconnection developed for data-processing applications like parallel optical computing, neural-network computing, and switching in optical communication networks. In method, multiple optical connections between multiple sources of light in one array and multiple photodetectors in another array made via computer-generated holograms in electrically addressed spatial light modulators (ESLMs). Offers potential advantages of massive parallelism, high space-bandwidth product, high time-bandwidth product, low power consumption, low cross talk, and low time skew. Also offers advantage of programmability with flexibility of reconfiguration, including variation of strengths of optical connections in real time.

  18. Applied study of optical interconnection link in computer cluster

    NASA Astrophysics Data System (ADS)

    Zhou, Ge; Tian, Jindong; Zhang, Nan; Jing, Wencai; Li, Haifeng

    2000-10-01

    In this paper, some study results to apply fiber link to a computer cluster are presented. The research is based on a ring network topology for a cluster system, which is connected by gigabit/s virtual parallel optical fiber link (VPOFLink) and its driver is for Linux Operating System, the transmission protocol of VPOFLink is compliant with Ethernet standard. We have studied the effect of different types of motherboard on transmission rate of the VPOFLink, and have analyzed the influence of optical interconnection network topology and computer networks protocol on the performance of this optical interconnection computer cluster. The round-trip transmission bandwidth of the VPOFLink have been tested, and the factors that limit transmission bandwidth, such as modes of forwarding data packets in the optical interconnection ring networks, and the size of the link buffer etc., are investigated.

  19. Polymeric optoelectronic interconnects

    NASA Astrophysics Data System (ADS)

    Eldada, Louay A.

    2000-04-01

    Electrical interconnects are reaching their fundamental limits and are becoming the speed bottleneck as processor speeds are increasing. A polymer-based interconnect technology was developed for affordable integrated optical circuits that address the optical signal processing needs in the telecom, datacom, and performance computing industries. We engineered organic polymers that can be readily made into 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, robustness, optical loss, thermal stability, and humidity resistance. 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 and exceptional environmental stability, enabling use in a variety of demanding applications. A wide range of rigid and flexible substrates can be used, including glass, quartz, silicon, glass-filled epoxy printed circuit board substrates, and flexible plastic films. The devices we describe include a variety of routing elements that can be sued as part of a massively parallel photonic integrated circuit on the MCM, board, or backplane level.

  20. Reconfigurable Hybrid Interconnection for Static and DynamicScientific Applications

    SciTech Connect

    Kamil, Shoaib; Pinar, Ali; Gunter, Daniel; Lijewski, Michael; Oliker, Leonid; Shalf, John; Skinner, David

    2006-04-25

    As we enter the era of petascale computing, system architects must plan for machines composed of tens of thousands or even hundreds of thousands of processors. Although fully connected networks such as fat-tree interconnects currently dominate HPC network designs, such approaches are inadequate for thousands of processors due to the superlinear growth of component costs. Traditional low-degree interconnect topologies, such as the 3D torus, have reemerged as a competitive solution because the number of switch components scales linearly with the node count, but such networks are poorly suited for the requirements of many scientific applications. We present our latest work on a hybrid switch architecture called HFAST that uses circuit switches to dynamically reconfigure a lower-degree interconnect to suit the topological requirements of each scientific application. This paper expands upon our prior work on the requirements of non-adaptive applications by analyzing the communication characteristics of dynamically adapting AMR code and presents a methodology that captures the evolving communication requirements. We also present a new optimization that computes the under-utilization of fat-tree interconnects for a given communication topology, showing the potential of constructing a ''fit-tree'' for the application by using the HFAST circuit switches to provision an optimal interconnect topology for each application. Finally, we apply our new optimization technique to the communication requirements of the AMR code to demonstrate the potential of using dynamic reconfiguration of the HFAST interconnect between the communication intensive phases of a dynamically adapting application.

  1. Fuel cell system with interconnect

    SciTech Connect

    Liu, Zhien; Goettler, Richard

    2015-09-29

    The present invention includes a fuel cell system having a plurality of adjacent electrochemical cells formed of an anode layer, a cathode layer spaced apart from the anode layer, and an electrolyte layer disposed between the anode layer and the cathode layer. The fuel cell system also includes at least one interconnect, the interconnect being structured to conduct free electrons between adjacent electrochemical cells. Each interconnect includes a primary conductor embedded within the electrolyte layer and structured to conduct the free electrons.

  2. Fuel cell system with interconnect

    SciTech Connect

    Goettler, Richard; Liu, Zhien

    2015-08-11

    The present invention includes a fuel cell system having a plurality of adjacent electrochemical cells formed of an anode layer, a cathode layer spaced apart from the anode layer, and an electrolyte layer disposed between the anode layer and the cathode layer. The fuel cell system also includes at least one interconnect, the interconnect being structured to conduct free electrons between adjacent electrochemical cells. Each interconnect includes a primary conductor embedded within the electrolyte layer and structured to conduct the free electrons.

  3. Fuel cell system with interconnect

    SciTech Connect

    Goettler, Richard; Liu, Zhien

    2015-03-10

    The present invention includes a fuel cell system having a plurality of adjacent electrochemical cells formed of an anode layer, a cathode layer spaced apart from the anode layer, and an electrolyte layer disposed between the anode layer and the cathode layer. The fuel cell system also includes at least one interconnect, the interconnect being structured to conduct free electrons between adjacent electrochemical cells. Each interconnect includes a primary conductor embedded within the electrolyte layer and structured to conduct the free electrons.

  4. A multistage model of hospital bed requirements.

    PubMed Central

    Pendergast, J F; Vogel, W B

    1988-01-01

    This article presents a model for projecting future hospital bed requirements, based on clinical judgment and basic probability theory. Clinical judgment is used to define various categories of care, including a category for patients who are inappropriately hospitalized, for a large teaching hospital with a heavy indigent and psychiatric workload. Survey results and discharge abstract data are then used to calculate expected discharges and patient days for each clinical category. These expected discharges and patient days are converted into estimated bed requirements using a simple deterministic equation. Results of this multistage model are compared with the results obtained from exercising the simple deterministic equation alone. Because the multistage model removes patients from the hospital if they are deemed inappropriately placed, this model results in the projection of 5.1 percent fewer hospital beds than the simple deterministic equation alone. PMID:3403276

  5. A Multistage Method for Multiobjective Route Selection

    NASA Astrophysics Data System (ADS)

    Wen, Feng; Gen, Mitsuo

    The multiobjective route selection problem (m-RSP) is a key research topic in the car navigation system (CNS) for ITS (Intelligent Transportation System). In this paper, we propose an interactive multistage weight-based Dijkstra genetic algorithm (mwD-GA) to solve it. The purpose of the proposed approach is to create enough Pareto-optimal routes with good distribution for the car driver depending on his/her preference. At the same time, the routes can be recalculated according to the driver's preferences by the multistage framework proposed. In the solution approach proposed, the accurate route searching ability of the Dijkstra algorithm and the exploration ability of the Genetic algorithm (GA) are effectively combined together for solving the m-RSP problems. Solutions provided by the proposed approach are compared with the current research to show the effectiveness and practicability of the solution approach proposed.

  6. Impedance characteristics of multistage ion diodes

    SciTech Connect

    Desjarlais, M.

    1994-09-01

    We further develop a theory of multistage diodes that includes the possibility of emission of ions in the final stage. The exact solutions are extremely cumbersome and are not practical for most applications. We have developed approximate solutions that are very accurate, require no integrations, and may be rapidly calculated using a simple iterative scheme. These solutions for the total current as a function of voltage are used in time-dependent modeling of a two-stage diode.

  7. Multi-stage sampling in genetic epidemiology.

    PubMed

    Whittemore, A S; Halpern, J

    When data are expensive to collect, it can be cost-efficient to sample in two or more stages. In the first stage a simple random sample is drawn and then stratified according to some easily measured attribute. In each subsequent stage a random subset of previously selected units is sampled for more detailed observation, with a unit's sampling probability determined by its attributes as observed in the previous stages. These designs are useful in many medical studies; here we use them in genetic epidemiology. Two genetic studies illustrate the strengths and limitations of the approach. The first study evaluates nuclear and mitochondrial DNA in U.S. blacks. The goal is to estimate the relative contributions of white male genes and white female genes to the gene pool of African-Americans. This example shows that the Horvitz-Thompson estimators proposed for multi-stage designs can be inefficient, particularly when used with unnecessary stratification. The second example is a multi-stage study of familial prostate cancer. The goal is to gather pedigrees, blood samples and archived tissue for segregation and linkage analysis of familial prostate cancer data by first obtaining crude family data from prostate cancer cases and cancer-free controls. This second example shows the gains in efficiency from multi-stage sampling when the individual likelihood or quasilikelihood scores vary substantially across strata. PMID:9004389

  8. Handling Imbalanced Data Sets in Multistage Classification

    NASA Astrophysics Data System (ADS)

    López, M.

    Multistage classification is a logical approach, based on a divide-and-conquer solution, for dealing with problems with a high number of classes. The classification problem is divided into several sequential steps, each one associated to a single classifier that works with subgroups of the original classes. In each level, the current set of classes is split into smaller subgroups of classes until they (the subgroups) are composed of only one class. The resulting chain of classifiers can be represented as a tree, which (1) simplifies the classification process by using fewer categories in each classifier and (2) makes it possible to combine several algorithms or use different attributes in each stage. Most of the classification algorithms can be biased in the sense of selecting the most populated class in overlapping areas of the input space. This can degrade a multistage classifier performance if the training set sample frequencies do not reflect the real prevalence in the population. Several techniques such as applying prior probabilities, assigning weights to the classes, or replicating instances have been developed to overcome this handicap. Most of them are designed for two-class (accept-reject) problems. In this article, we evaluate several of these techniques as applied to multistage classification and analyze how they can be useful for astronomy. We compare the results obtained by classifying a data set based on Hipparcos with and without these methods.

  9. Bioactive macroporous titanium implants highly interconnected.

    PubMed

    Caparrós, Cristina; Ortiz-Hernandez, Mónica; Molmeneu, Meritxell; Punset, Miguel; Calero, José Antonio; Aparicio, Conrado; Fernández-Fairén, Mariano; Perez, Román; Gil, Francisco Javier

    2016-10-01

    Intervertebral implants should be designed with low load requirements, high friction coefficient and low elastic modulus in order to avoid the stress shielding effect on bone. Furthermore, the presence of a highly interconnected porous structure allows stimulating bone in-growth and enhancing implant-bone fixation. The aim of this study was to obtain bioactive porous titanium implants with highly interconnected pores with a total porosity of approximately 57 %. Porous Titanium implants were produced by powder sintering route using the space holder technique with a binder phase and were then evaluated in an in vivo study. The size of the interconnection diameter between the macropores was about 210 μm in order to guarantee bone in-growth through osteblastic cell penetration. Surface roughness and mechanical properties were analyzed. Stiffness was reduced as a result of the powder sintering technique which allowed the formation of a porous network. Compression and fatigue tests exhibited suitable properties in order to guarantee a proper compromise between mechanical properties and pore interconnectivity. Bioactivity treatment effect in novel sintered porous titanium materials was studied by thermo-chemical treatments and were compared with the same material that had undergone different bioactive treatments. Bioactive thermo-chemical treatment was confirmed by the presence of sodium titanates on the surface of the implants as well as inside the porous network. Raman spectroscopy results suggested that the identified titanate structures would enhance in vivo apatite formation by promoting ion exchange for the apatite formation process. In vivo results demonstrated that the bioactive titanium achieved over 75 % tissue colonization compared to the 40 % value for the untreated titanium. PMID:27582071

  10. Process for electrically interconnecting electrodes

    DOEpatents

    Carey, Paul G.; Thompson, Jesse B.; Colella, Nicolas J.; Williams, Kenneth A.

    2002-01-01

    Electrical interconnects for solar cells or other electronic components using a silver-silicone paste or a lead-tin (Pb--Sn) no-clean fluxless solder cream, whereby the high breakage of thin (<6 mil thick) solar cells using conventional solder interconnect is eliminated. The interconnects of this invention employs copper strips which are secured to the solar cells by a silver-silicone conductive paste which can be used at room temperature, or by a Pb--Sn solder cream which eliminates undesired residue on the active surfaces of the solar cells. Electrical testing using the interconnects of this invention has shown that no degradation of the interconnects developed under high current testing, while providing a very low contact resistance value.

  11. 47 CFR 51.321 - Methods of obtaining interconnection and access to unbundled elements under section 251 of the Act.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... or access to unbundled network elements at a particular point upon a request by a telecommunications carrier. (b) Technically feasible methods of obtaining interconnection or access to unbundled network... method of obtaining interconnection or access to unbundled network elements at a particular premises...

  12. 47 CFR 51.321 - Methods of obtaining interconnection and access to unbundled elements under section 251 of the Act.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... or access to unbundled network elements at a particular point upon a request by a telecommunications carrier. (b) Technically feasible methods of obtaining interconnection or access to unbundled network... method of obtaining interconnection or access to unbundled network elements at a particular premises...

  13. SIDES - Segment Interconnect Diagnostic Expert System

    SciTech Connect

    Booth, A.W.; Forster, R.; Gustafsson, L.; Ho, N.

    1989-02-01

    It is well known that the FASTBUS Segment Interconnect (SI) provides a communication path between two otherwise independent, asynchronous bus segments. The SI is probably the most important module in any FASTBUS data acquisition network since it's failure to function can cause whole segments of the network to be inaccessible and sometimes inoperable. This paper describes SIDES, an intelligent program designed to diagnose SI's both in situ as they operate in a data acquisition network, and in the laboratory in an acceptance/repair environment. The paper discusses important issues such as knowledge acquisition; extracting knowledge from human experts and other knowledge sources. SIDES can benefit high energy physics experiments, where SI problems can be diagnosed and solved more quickly. Equipment pool technicians can also benefit from SIDES, first by decreasing the number of SI's erroneously turned in for repair, and secondly as SIDES acts as an intelligent assistant to the technician in the diagnosis and repair process.

  14. Reconfigurable high-speed optoelectronic interconnect technology for multiprocessor computers

    NASA Astrophysics Data System (ADS)

    Cheng, Julian

    1995-06-01

    We describe a compact optoelectronic switching technology for interconnecting multiple computer processors and shared memory modules together through dynamically reconfigurable optical paths to provide simultaneous, high speed communication amongst different nodes. Each switch provides a optical link to other nodes as well as electrical access to an individual processor, and it can perform optical and optoelectronic switching to covert digital data between various electrical and optical input/output formats. This multifunctional switching technology is based on the monolithic integration of arrays of vertical-cavity surface-emitting lasers with photodetectors and heterojunction bipolar transistors. The various digital switching and routing functions, as well as optically cascaded multistage operation, have been experimentally demonstrated.

  15. Implementation of interconnect simulation tools in spice

    NASA Technical Reports Server (NTRS)

    Satsangi, H.; Schutt-Aine, J. E.

    1993-01-01

    Accurate computer simulation of high speed digital computer circuits and communication circuits requires a multimode approach to simulate both the devices and the interconnects between devices. Classical circuit analysis algorithms (lumped parameter) are needed for circuit devices and the network formed by the interconnected devices. The interconnects, however, have to be modeled as transmission lines which incorporate electromagnetic field analysis. An approach to writing a multimode simulator is to take an existing software package which performs either lumped parameter analysis or field analysis and add the missing type of analysis routines to the package. In this work a traditionally lumped parameter simulator, SPICE, is modified so that it will perform lossy transmission line analysis using a different model approach. Modifying SPICE3E2 or any other large software package is not a trivial task. An understanding of the programming conventions used, simulation software, and simulation algorithms is required. This thesis was written to clarify the procedure for installing a device into SPICE3E2. The installation of three devices is documented and the installations of the first two provide a foundation for installation of the lossy line which is the third device. The details of discussions are specific to SPICE, but the concepts will be helpful when performing installations into other circuit analysis packages.

  16. Butterfly interconnection implementation for an n-bit parallel ripple carry full adder.

    PubMed

    Sun, D G; Weng, Z H

    1991-05-10

    Free-space optical interconnections are important both in massive digital optical computing and in communication systems. The optical butterfly interconnection has many advantages over other interconnections in implementing various basic logic functions such as addition, subtraction, multiplication. This paper starts with the conventional Karnaugh maps and Boolean algebra to implement a parallel n-bit ripple carry full adder by the use of multilayer butterfly interconnection networks. Then we describe in detail the design and architecture of the full adder and provide accurate interconnection networks and the structures or patterns of key devices such as the masks to implement AND and OR operations in this calculation. Finally, we discuss development of the interconnection in implementing logic operations. PMID:20700358

  17. Interconnect resistance of photovoltaic submodules

    NASA Technical Reports Server (NTRS)

    Volltrauer, H.; Eser, E.; Delahoy, A. E.

    1985-01-01

    Small area amorphous silicon solar cells generally have higher efficiencies than large interconnected submodules. Among the reasons for the differences in performance are the lack of large area uniformity, the effect of nonzero tin oxide sheet resistance, and possibly pinholes in the various layers. Another and usually small effect that can contribute to reduced performance of interconnected cells is the resistance of the interconnection i.e., the series resistance introduced by the metal to tin oxide contact through silicon. Proper processing problems to avoid poor contacts are discussed.

  18. Renewable Systems Interconnection: Executive Summary

    SciTech Connect

    Kroposki, B.; Margolis, R.; Kuswa, G.; Torres, J.; Bower, W.; Key, T.; Ton, D.

    2008-02-01

    The U.S. Department of Energy launched the Renewable Systems Interconnection (RSI) study in 2007 to address the challenges to high penetrations of distributed renewable energy technologies. The RSI study consists of 14 additional reports.

  19. Parallel optical interconnects utilizing VLSI/FLC spatial light modulators

    NASA Astrophysics Data System (ADS)

    Genco, Sheryl M.

    1991-12-01

    Interconnection architectures are a cornerstone of parallel computing systems. However, interconnections can be a bottleneck in conventional computer architectures because of queuing structures that are necessary to handle the traffic through a switch at very high data rates and bandwidths. These issues must find new solutions to advance the state of the art in computing beyond the fundamental limit of silicon logic technology. Today's optoelectronic (OE) technology in particular VLSI/FLC spatial light modulators (SLMs) can provide a unique and innovative solution to these issues. This paper reports on the motivations for the system, describes the major areas of architectural requirements, discusses interconnection topologies and processor element alternatives, and documents an optical arbitration (i.e., control) scheme using `smart' SLMs and optical logic gates. The network topology is given in section 2.1 `Architectural Requirements -- Networks,' but it should be noted that the emphasis is on the optical control scheme (section 2.4) and the system.

  20. Multistage Zeeman deceleration of metastable neon

    SciTech Connect

    Wiederkehr, Alex W.; Motsch, Michael; Hogan, Stephen D.; Andrist, Markus; Schmutz, Hansjuerg; Lambillotte, Bruno; Agner, Josef A.; Merkt, Frederic

    2011-12-07

    A supersonic beam of metastable neon atoms has been decelerated by exploiting the interaction between the magnetic moment of the atoms and time-dependent inhomogeneous magnetic fields in a multistage Zeeman decelerator. Using 91 deceleration solenoids, the atoms were decelerated from an initial velocity of 580 m/s to final velocities as low as 105 m/s, corresponding to a removal of more than 95% of their initial kinetic energy. The phase-space distribution of the cold, decelerated atoms was characterized by time-of-flight and imaging measurements, from which a temperature of 10 mK was obtained in the moving frame of the decelerated sample. In combination with particle-trajectory simulations, these measurements allowed the phase-space acceptance of the decelerator to be quantified. The degree of isotope separation that can be achieved by multistage Zeeman deceleration was also studied by performing experiments with pulse sequences generated for {sup 20}Ne and {sup 22}Ne.

  1. Multistage Zeeman deceleration of metastable neon.

    PubMed

    Wiederkehr, Alex W; Motsch, Michael; Hogan, Stephen D; Andrist, Markus; Schmutz, Hansjürg; Lambillotte, Bruno; Agner, Josef A; Merkt, Frédéric

    2011-12-01

    A supersonic beam of metastable neon atoms has been decelerated by exploiting the interaction between the magnetic moment of the atoms and time-dependent inhomogeneous magnetic fields in a multistage Zeeman decelerator. Using 91 deceleration solenoids, the atoms were decelerated from an initial velocity of 580 m/s to final velocities as low as 105 m/s, corresponding to a removal of more than 95% of their initial kinetic energy. The phase-space distribution of the cold, decelerated atoms was characterized by time-of-flight and imaging measurements, from which a temperature of 10 mK was obtained in the moving frame of the decelerated sample. In combination with particle-trajectory simulations, these measurements allowed the phase-space acceptance of the decelerator to be quantified. The degree of isotope separation that can be achieved by multistage Zeeman deceleration was also studied by performing experiments with pulse sequences generated for (20)Ne and (22)Ne. PMID:22149785

  2. Multistage adsorption of diffusing macromolecules and viruses

    NASA Astrophysics Data System (ADS)

    Chou, Tom; D'Orsogna, Maria R.

    2007-09-01

    We derive the equations that describe adsorption of diffusing particles onto a surface followed by additional surface kinetic steps before being transported across the interface. Multistage surface kinetics occurs during membrane protein insertion, cell signaling, and the infection of cells by virus particles. For example, viral entry into healthy cells is possible only after a series of receptor and coreceptor binding events occurs at the cellular surface. We couple the diffusion of particles in the bulk phase with the multistage surface kinetics and derive an effective, integrodifferential boundary condition that contains a memory kernel embodying the delay induced by the surface reactions. This boundary condition takes the form of a singular perturbation problem in the limit where particle-surface interactions are short ranged. Moreover, depending on the surface kinetics, the delay kernel induces a nonmonotonic, transient replenishment of the bulk particle concentration near the interface. The approach generalizes that of Ward and Tordai [J. Chem. Phys. 14, 453 (1946)] and Diamant and Andelman [Colloids Surf. A 183-185, 259 (2001)] to include surface kinetics, giving rise to qualitatively new behaviors. Our analysis also suggests a simple scheme by which stochastic surface reactions may be coupled to deterministic bulk diffusion.

  3. Exposure Control Using Adaptive Multi-Stage Item Bundles.

    ERIC Educational Resources Information Center

    Luecht, Richard M.

    This paper presents a multistage adaptive testing test development paradigm that promises to handle content balancing and other test development needs, psychometric reliability concerns, and item exposure. The bundled multistage adaptive testing (BMAT) framework is a modification of the computer-adaptive sequential testing framework introduced by…

  4. 40 CFR 600.316-78 - Multistage manufacture.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and Later Model Year Automobiles-Labeling § 600.316-78 Multistage manufacture. Where more than one person is the manufacturer of a vehicle, the final stage vehicle manufacturer (as defined in 49 CFR 549.3... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Multistage manufacture....

  5. 40 CFR 600.316-78 - Multistage manufacture.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and Later Model Year Automobiles-Labeling § 600.316-78 Multistage manufacture. Where more than one person is the manufacturer of a vehicle, the final stage vehicle manufacturer (as defined in 49 CFR 549.3... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Multistage manufacture....

  6. 40 CFR 600.316-08 - Multistage manufacture.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Multistage manufacture. Where more than one person is the manufacturer of a vehicle, the final stage manufacturer (as defined in 49 CFR 529.3) is treated as the vehicle manufacturer for purposes of compliance... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Multistage manufacture....

  7. Interconnecting Networks of Practice for Professional Learning

    ERIC Educational Resources Information Center

    Mackey, Julie; Evans, Terry

    2011-01-01

    The article explores the complementary connections between communities of practice and the ways in which individuals orchestrate their engagement with others to further their professional learning. It does so by reporting on part of a research project conducted in New Zealand on teachers' online professional learning in a university graduate…

  8. The performance of multicomputer interconnection networks

    SciTech Connect

    Reed, D.A.; Grunwald, D.C.

    1987-06-01

    The spectrum of parallel processor designs can be divided into three sections according to the number and complexity of the processors. At one end there are simple, bit-serial processors. Any one of thee processors is of little value, but when it is coupled with many others, the aggregate computing power can be large. This approach to parallel processing can be likened to a colony of termites devouring a log. The most notable examples of this approach are the NASA/Goodyear Massively Parallel Processor, which has 16K one-bit processors, and the Thinking Machines Connection Machine, which has 64K one-bit processors. At the other end of the spectrum, a small number of processors, each built using the fastest available technology and the most sophisticated architecture, are combined. An example of this approach is the Cray X-MP. This type of parallel processing is akin to four woodmen attacking the log with chainsaws.

  9. Message Passing Framework for Globally Interconnected Clusters

    NASA Astrophysics Data System (ADS)

    Hafeez, M.; Asghar, S.; Malik, U. A.; Rehman, A.; Riaz, N.

    2011-12-01

    In prevailing technology trends it is apparent that the network requirements and technologies will advance in future. Therefore the need of High Performance Computing (HPC) based implementation for interconnecting clusters is comprehensible for scalability of clusters. Grid computing provides global infrastructure of interconnecting clusters consisting of dispersed computing resources over Internet. On the other hand the leading model for HPC programming is Message Passing Interface (MPI). As compared to Grid computing, MPI is better suited for solving most of the complex computational problems. MPI itself is restricted to a single cluster. It does not support message passing over the internet to use the computing resources of different clusters in an optimal way. We propose a model that provides message passing capabilities between parallel applications over the internet. The proposed model is based on Architecture for Java Universal Message Passing (A-JUMP) framework and Enterprise Service Bus (ESB) named as High Performance Computing Bus. The HPC Bus is built using ActiveMQ. HPC Bus is responsible for communication and message passing in an asynchronous manner. Asynchronous mode of communication offers an assurance for message delivery as well as a fault tolerance mechanism for message passing. The idea presented in this paper effectively utilizes wide-area intercluster networks. It also provides scheduling, dynamic resource discovery and allocation, and sub-clustering of resources for different jobs. Performance analysis and comparison study of the proposed framework with P2P-MPI are also presented in this paper.

  10. European Transmission Interconnection; Eurasian power grid

    SciTech Connect

    Posch, J. )

    1991-09-01

    Systems and philosophies perceived on a grand scale, encompassing new ideas, are often characterized as a dream. But in fact, such dreams often lead to the first step to fruitful development. This article is based on a preliminary study of the existing electrical high-tension networks of Western Europe, Eastern Europe and the Soviet Union - which, as explained herein, may be merged into a multinational energy supply system. Such a system would constitute a completely interconnected Eurasian Power Grid. The idea of a Eurasian super grid, spanning from the Atlantic to the Ural and Siberia, is not new. Various studies have been conducted by both western Europe and the Soviet Union on this topic. Our world is currently in an era of extra high voltage (EHV) and ultra high voltage (UHV) electrical systems. This translates into existing UHV lines of 1150 kV which have already been proven in successful operation. Such UHV systems are capable of transmitting thousands of megawatts over a distance of a 1000 miles. Furthermore, national boundaries are not more a hindrance than the challenge of interconnecting complete networks into an overall synchronized working system with load exchange capabilities in all directions.

  11. Misalignment corrections in optical interconnects

    NASA Astrophysics Data System (ADS)

    Song, Deqiang

    Optical interconnects are considered a promising solution for long distance and high bitrate data transmissions, outperforming electrical interconnects in terms of loss and dispersion. Due to the bandwidth and distance advantage of optical interconnects, longer links have been implemented with optics. Recent studies show that optical interconnects have clear advantages even at very short distances---intra system interconnects. The biggest challenge for such optical interconnects is the alignment tolerance. Many free space optical components require very precise assembly and installation, and therefore the overall cost could be increased. This thesis studied the misalignment tolerance and possible alignment correction solutions for optical interconnects at backplane or board level. First the alignment tolerance for free space couplers was simulated and the result indicated the most critical alignments occur between the VCSEL, waveguide and microlens arrays. An in-situ microlens array fabrication method was designed and experimentally demonstrated, with no observable misalignment with the waveguide array. At the receiver side, conical lens arrays were proposed to replace simple microlens arrays for a larger angular alignment tolerance. Multilayer simulation models in CodeV were built to optimized the refractive index and shape profiles of the conical lens arrays. Conical lenses fabricated with micro injection molding machine and fiber etching were characterized. Active component VCSOA was used to correct misalignment in optical connectors between the board and backplane. The alignment correction capability were characterized for both DC and AC (1GHz) optical signal. The speed and bandwidth of the VCSOA was measured and compared with a same structure VCSEL. Based on the optical inverter being studied in our lab, an all-optical flip-flop was demonstrated using a pair of VCSOAs. This memory cell with random access ability can store one bit optical signal with set or

  12. Biologically based multistage modeling of radiation effects

    SciTech Connect

    William Hazelton; Suresh Moolgavkar; E. Georg Luebeck

    2005-08-30

    This past year we have made substantial progress in modeling the contribution of homeostatic regulation to low-dose radiation effects and carcinogenesis. We have worked to refine and apply our multistage carcinogenesis models to explicitly incorporate cell cycle states, simple and complex damage, checkpoint delay, slow and fast repair, differentiation, and apoptosis to study the effects of low-dose ionizing radiation in mouse intestinal crypts, as well as in other tissues. We have one paper accepted for publication in ''Advances in Space Research'', and another manuscript in preparation describing this work. I also wrote a chapter describing our combined cell-cycle and multistage carcinogenesis model that will be published in a book on stochastic carcinogenesis models edited by Wei-Yuan Tan. In addition, we organized and held a workshop on ''Biologically Based Modeling of Human Health Effects of Low dose Ionizing Radiation'', July 28-29, 2005 at Fred Hutchinson Cancer Research Center in Seattle, Washington. We had over 20 participants, including Mary Helen Barcellos-Hoff as keynote speaker, talks by most of the low-dose modelers in the DOE low-dose program, experimentalists including Les Redpath (and Mary Helen), Noelle Metting from DOE, and Tony Brooks. It appears that homeostatic regulation may be central to understanding low-dose radiation phenomena. The primary effects of ionizing radiation (IR) are cell killing, delayed cell cycling, and induction of mutations. However, homeostatic regulation causes cells that are killed or damaged by IR to eventually be replaced. Cells with an initiating mutation may have a replacement advantage, leading to clonal expansion of these initiated cells. Thus we have focused particularly on modeling effects that disturb homeostatic regulation as early steps in the carcinogenic process. There are two primary considerations that support our focus on homeostatic regulation. First, a number of epidemiologic studies using multistage

  13. Multistaged stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A.

    1980-01-01

    A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

  14. Modern multistage depressed collectors - A review

    NASA Technical Reports Server (NTRS)

    Kosmahl, H. G.

    1982-01-01

    The design and performance of the Lewis Research Center (LeRC) electrostatic collector and the associated passive permanent magnetic beam reconditioning (refocusing) are discussed and compared with numerous experimental results on wide- and narrow-band TWT and two klystron cases. Universal designs for efficient collectors for TV klystrons are presented. Collectors other than those based on the symmetric LeRC concept are reviewed only briefly, either because they have not been treated analytically or because only sporadic or incomplete experimental evaluation results are available. It is concluded that significant, a priori predictable performance improvements for TWTs have been demonstrated and that a substantial reduction in the dc power input to TV klystron transmitters could be effected by using well-designed multistage depressed collectors.

  15. Vibration signature analysis of multistage gear transmission

    NASA Technical Reports Server (NTRS)

    Choy, F. K.; Tu, Y. K.; Savage, M.; Townsend, D. P.

    1989-01-01

    An analysis is presented for multistage multimesh gear transmission systems. The analysis predicts the overall system dynamics and the transmissibility to the gear box or the enclosed structure. The modal synthesis approach of the analysis treats the uncoupled lateral/torsional model characteristics of each stage or component independently. The vibration signature analysis evaluates the global dynamics coupling in the system. The method synthesizes the interaction of each modal component or stage with the nonlinear gear mesh dynamics and the modal support geometry characteristics. The analysis simulates transient and steady state vibration events to determine the resulting torque variations, speeds, changes, rotor imbalances, and support gear box motion excitations. A vibration signature analysis examines the overall dynamic characteristics of the system, and the individual model component responses. The gear box vibration analysis also examines the spectral characteristics of the support system.

  16. Modern multistage depressed collectors - A review

    NASA Astrophysics Data System (ADS)

    Kosmahl, H. G.

    1982-11-01

    The design and performance of the Lewis Research Center (LeRC) electrostatic collector and the associated passive permanent magnetic beam reconditioning (refocusing) are discussed and compared with numerous experimental results on wide- and narrow-band TWT and two klystron cases. Universal designs for efficient collectors for TV klystrons are presented. Collectors other than those based on the symmetric LeRC concept are reviewed only briefly, either because they have not been treated analytically or because only sporadic or incomplete experimental evaluation results are available. It is concluded that significant, a priori predictable performance improvements for TWTs have been demonstrated and that a substantial reduction in the dc power input to TV klystron transmitters could be effected by using well-designed multistage depressed collectors.

  17. Manufacturing of planar ceramic interconnects

    SciTech Connect

    Armstrong, B.L.; Coffey, G.W.; Meinhardt, K.D.; Armstrong, T.R.

    1996-12-31

    The fabrication of ceramic interconnects for solid oxide fuel cells (SOFC) and separator plates for electrochemical separation devices has been a perennial challenge facing developers. Electrochemical vapor deposition (EVD), plasma spraying, pressing, tape casting and tape calendering are processes that are typically utilized to fabricate separator plates or interconnects for the various SOFC designs and electrochemical separation devices. For sake of brevity and the selection of a planar fuel cell or gas separation device design, pressing will be the only fabrication technique discussed here. This paper reports on the effect of the characteristics of two doped lanthanum manganite powders used in the initial studies as a planar porous separator for a fuel cell cathode and as a dense interconnect for an oxygen generator.

  18. Singularity analysis and elimination of CMA in multistage PMD channel model

    NASA Astrophysics Data System (ADS)

    Nie, Xinhui; Li, Yan; Du, Wentao; Cheng, Haiquan; Wu, Jian; Li, Wei; Lin, Jintong; Lu, Jianxin; Xu, Jian; Zhang, Guoyi; Luo, Huihong

    2015-08-01

    Polarization-division-multiplexed(PDM) optical coherent systems is considered a promising technique for next generation optical networks. With coherent detection, various impairments in the optical transmission system can be compensated by using digital signal processing (DSP) in the electrical domain. Constant modulus algorithm (CMA), due to its simplicity and immunity to phase noise, has been widely used to demultiplex polarizations and compensate received signals. On the other hand, CMA suffers from the singularity problem which results from Polarization- Dependent-Loss (PDL) and the less sensitivity in phase of CMA. Although many people have researched the singularity problem of CMA both in theory and experiments (modify CMA to avoid singularity problem), their theoretical channel model only contains fiber birefringence and does not consider the situation of multistage channel model which is used in long distance transmission system. Then we analyse the performance of CMA in the channel with multistage channel model through simulation. We change the initial tap of the traditional CMA which can achieve correct polarization demultiplexing without singularity in one stage channel model. But it is not very suitable in multistage channel model. We analysed singularity ratio in long distance transmission system. The simulation results play an active role in following research on singularity problem and the performance of CMA.

  19. Multi-stage internal gear/turbine fuel pump

    DOEpatents

    Maier, Eugen; Raney, Michael Raymond

    2004-07-06

    A multi-stage internal gear/turbine fuel pump for a vehicle includes a housing having an inlet and an outlet and a motor disposed in the housing. The multi-stage internal gear/turbine fuel pump also includes a shaft extending axially and disposed in the housing. The multi-stage internal gear/turbine fuel pump further includes a plurality of pumping modules disposed axially along the shaft. One of the pumping modules is a turbine pumping module and another of the pumping modules is a gerotor pumping module for rotation by the motor to pump fuel from the inlet to the outlet.

  20. Dynamically reconfigurable optical interconnect architecture for parallel multiprocessor systems

    NASA Astrophysics Data System (ADS)

    Girard, Mary M.; Husbands, Charles R.; Antoszewska, Reza

    1991-12-01

    The progress in parallel processing technology in recent years has resulted in increased requirements to process large amounts of data in real time. The massively parallel architectures proposed for these applications require the use of a high speed interconnect system to achieve processor-to-processor connectivity without incurring excessive delays. The characteristics of optical components permit high speed operation while the nonconductive nature of the optical medium eliminates ground loop and transmission line problems normally associated with a conductive medium. The MITRE Corp. is evaluating an optical wavelength division multiple access interconnect network design to improve interconnectivity within parallel processor systems and to allow reconfigurability of processor communication paths. This paper describes the architecture and control of and highlights the results from an 8- channel multiprocessor prototype with effective throughput of 3.2 Gigabits per second (Gbps).

  1. Mapping of interconnection of climate risks

    NASA Astrophysics Data System (ADS)

    Yokohata, Tokuta; Tanaka, Katsumasa; Nishina, Kazuya; Takanashi, Kiyoshi; Emori, Seita; Kiguchi, Masashi; Iseri, Yoshihiko; Honda, Yasushi; Okada, Masashi; Masaki, Yoshimitsu; Yamamoto, Akitomo; Shigemitsu, Masahito; Yoshimori, Masakazu; Sueyoshi, Tetsuo; Iwase, Kenta; Hanasaki, Naota; Ito, Akihiko; Sakurai, Gen; Iizumi, Toshichika; Oki, Taikan

    2015-04-01

    Anthropogenic climate change possibly causes various impacts on human society and ecosystem. Here, we call possible damages or benefits caused by the future climate change as "climate risks". Many climate risks are closely interconnected with each other by direct cause-effect relationship. In this study, the major climate risks are comprehensively summarized based on the survey of studies in the literature using IPCC AR5 etc, and their cause-effect relationship are visualized by a "network diagram". This research is conducted by the collaboration between the experts of various fields, such as water, energy, agriculture, health, society, and eco-system under the project called ICA-RUS (Integrated Climate Assessment - Risks, Uncertainties and Society). First, the climate risks are classified into 9 categories (water, energy, food, health, disaster, industry, society, ecosystem, and tipping elements). Second, researchers of these fields in our project survey the research articles, and pick up items of climate risks, and possible cause-effect relationship between the risk items. A long list of the climate risks is summarized into ~130, and that of possible cause-effect relationship between the risk items is summarized into ~300, because the network diagram would be illegible if the number of the risk items and cause-effect relationship is too large. Here, we only consider the risks that could occur if climate mitigation policies are not conducted. Finally, the chain of climate risks is visualized by creating a "network diagram" based on a network graph theory (Fruchtman & Reingold algorithm). Through the analysis of network diagram, we find that climate risks at various sectors are closely related. For example, the decrease in the precipitation under the global climate change possibly causes the decrease in river runoff and the decrease in soil moisture, which causes the changes in crop production. The changes in crop production can have an impact on society by

  2. Aspects of short-range interconnect packaging

    NASA Astrophysics Data System (ADS)

    Wohlfeld, Denis; Brenner, Karl-Heinz

    2012-01-01

    In short-range interconnect applications, one question arises frequently: When should optical solutions be chosen over electrical wiring? The answer to this question of course depends on several factors like costs, performance, reliability, availability of testing equipment and knowledge about optical technologies, and last but not least, it strongly depends on the application itself. Networking in high performance computing (HPC) is one such example. With bit rates around 10 Gbit/s per channel and cable length above 2 m, the high attenuation of electrical cables leads to a clear preference of optical or active optical cables (AOC) for most planned HPC systems. For AOCs, the electro-optical conversion is realized inside the connector housing, while for purely optical cables, the conversion is done at the edge of the board. Proceeding to 25 Gbit/s and higher, attenuation and loss of signal quality become critical. Therefore, either significantly more effort has to be spent on the electrical side, or the package for conversion has to be integrated closer to the chip, thus requiring new packaging technologies. The paper provides a state of the art overview of packaging concepts for short range interconnects, it describes the main challenges of optical package integration and illustrates new concepts and trends in this research area.

  3. Polyguide polymeric technology for optical interconnect circuits and components

    NASA Astrophysics Data System (ADS)

    Booth, Bruce L.; Marchegiano, Joseph E.; Chang, Catherine T.; Furmanak, Robert J.; Graham, Douglas M.; Wagner, Richard G.

    1997-04-01

    The expanding information revolution has been made possible by the development of optical communication technology. To meet the escalating demand for information transmitted and processed at high data rates and the need to circumvent the growing electronic circuit bottlenecks, mass deployment of not only optical fiber networks but manufacturable optical interconnect circuits, components and connectors for interfacing fibers and electronics that meet economic and performance constraints are absolutely necessary. Polymeric waveguide optical interconnection are considered increasingly important to meet these market needs. DuPont's polyguide polymeric integrated optic channel waveguide system is thought by many to have considerable potential for a broad range of passive optical interconnect applications. In this paper the recent advances, status, and unique attributes of the technology are reviewed. Product and technology developments currently in progress including parallel optical ink organization and polymer optical interconnect technology developments funded by DARPA are used as examples to describe polyguide breadth and potential for manufacture and deployment of optical interconnection products for single and multimode telecom and datacom waveguide applications.

  4. Solving a multistage partial inspection problem using genetic algorithms

    SciTech Connect

    Heredia-Langner, Alejandro ); Montgomery, D C.; Carlyle, W M.

    2002-01-01

    Traditionally, the multistage inspection problem has been formulated as consisting of a decision schedule where some manufacturing stages receive full inspection and the rest none. Dynamic programming and heuristic methods (like local search) are the most commonly used solution techniques. A highly constrained multistage inspection problem is presented where all stages must receive partial rectifying inspection and it is solved using a real-valued genetic algorithm. This solution technique can handle multiple objectives and quality constraints effectively.

  5. Interconnecting compressors control coalbed gas production

    SciTech Connect

    Payton, R.; Niederhofer, J. )

    1992-10-05

    This paper reports that centralized compressors afford Taurus Exploration Inc.'s coalbed gas operations optimum control of gas production. Unlike satellite stations, the centralized system allows methane gas to e shifted from station to station via the interconnecting low-pressure pipeline network. The operations area encompasses approximately 40,000 acres, about 40 miles southwest of Birmingham, Ala. The project includes about 250-miles of low-pressure gas flow lines to almost 400 wells. The centralized system is less costly than a satellite station to build and operate. Unlike a satellite station that requires each compressor to have a complete set of ancillary equipment, the centralized system requires only one suction manifold, one dehydration setup, and one metering facility for every five compressor sets.

  6. A novel multistage estimation of signal parameters

    NASA Technical Reports Server (NTRS)

    Kumar, Rajendra

    1990-01-01

    A multistage estimation scheme is presented for estimating the parameters of a received carrier signal possibly phase-modulated by unknown data and experiencing very high Doppler, Doppler rate, etc. Such a situation arises, for example, in the case of the Global Positioning Systems (GPS). In the proposed scheme, the first-stage estimator operates as a coarse estimator of the frequency and its derivatives, resulting in higher rms estimation errors but with a relatively small probability of the frequency estimation error exceeding one-half of the sampling frequency (an event termed cycle slip). The second stage of the estimator operates on the error signal available from the first stage, refining the overall estimates, and in the process also reduces the number of cycle slips. The first-stage algorithm is a modified least-squares algorithm operating on the differential signal model and referred to as differential least squares (DLS). The second-stage algorithm is an extended Kalman filter, which yields the estimate of the phase as well as refining the frequency estimate. A major advantage of the is a reduction in the threshold for the received carrier power-to-noise power spectral density ratio (CNR) as compared with the threshold achievable by either of the algorithms alone.

  7. Multistage carcinogenesis in the urinary bladder.

    PubMed Central

    Cohen, S M; Greenfield, R E; Ellwein, L B

    1983-01-01

    The induction of cancer of the urinary bladder is a multi-stage process involving multiple exogenous and endogenous factors. Based on the classical initiation-promotion model, we have used N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) as initiator and sodium saccharin (SAC) or tryptophan as promoters. These latter chemicals have the properties expected of promoters: induction of hyperplasia, reversibility and nonmutagenicity. Also, tumors were induced whether the promoter was administered immediately after FANFT or beginning 6 weeks after FANFT was discontinued, but no tumors resulted if either promoter was given without initiation with FANFT. Factor(s) present in normal urine also are involved in the promotion process, in addition to the role of urine as a carrier of carcinogens. However, administration of SAC to animals with a rapidly proliferating bladder mucosa, induced by ulceration, pellet insertion, or in utero, resulted in bladder tumor induction, even without prior initiation with FANFT. To better understand the complex interaction of the multiple variables in bladder carcinogenesis, a stochastic computer model has been formulated based on long-term carcinogenicity and tissue kinetic studies in vivo. This model indicates the importance of cell proliferation and the development of hyperplasia in carcinogenesis. PMID:6832093

  8. Computational analysis of a multistage axial compressor

    NASA Astrophysics Data System (ADS)

    Mamidoju, Chaithanya

    Turbomachines are used extensively in Aerospace, Power Generation, and Oil & Gas Industries. Efficiency of these machines is often an important factor and has led to the continuous effort to improve the design to achieve better efficiency. The axial flow compressor is a major component in a gas turbine with the turbine's overall performance depending strongly on compressor performance. Traditional analysis of axial compressors involves throughflow calculations, isolated blade passage analysis, Quasi-3D blade-to-blade analysis, single-stage (rotor-stator) analysis, and multi-stage analysis involving larger design cycles. In the current study, the detailed flow through a 15 stage axial compressor is analyzed using a 3-D Navier Stokes CFD solver in a parallel computing environment. Methodology is described for steady state (frozen rotor stator) analysis of one blade passage per component. Various effects such as mesh type and density, boundary conditions, tip clearance and numerical issues such as turbulence model choice, advection model choice, and parallel processing performance are analyzed. A high sensitivity of the predictions to the above was found. Physical explanation to the flow features observed in the computational study are given. The total pressure rise verses mass flow rate was computed.

  9. Automatic variance analysis of multistage care pathways.

    PubMed

    Li, Xiang; Liu, Haifeng; Zhang, Shilei; Mei, Jing; Xie, Guotong; Yu, Yiqin; Li, Jing; Lakshmanan, Geetika T

    2014-01-01

    A care pathway (CP) is a standardized process that consists of multiple care stages, clinical activities and their relations, aimed at ensuring and enhancing the quality of care. However, actual care may deviate from the planned CP, and analysis of these deviations can help clinicians refine the CP and reduce medical errors. In this paper, we propose a CP variance analysis method to automatically identify the deviations between actual patient traces in electronic medical records (EMR) and a multistage CP. As the care stage information is usually unavailable in EMR, we first align every trace with the CP using a hidden Markov model. From the aligned traces, we report three types of deviations for every care stage: additional activities, absent activities and violated constraints, which are identified by using the techniques of temporal logic and binomial tests. The method has been applied to a CP for the management of congestive heart failure and real world EMR, providing meaningful evidence for the further improvement of care quality. PMID:25160280

  10. Some recommendations for multi-arm multi-stage trials.

    PubMed

    Wason, James; Magirr, Dominic; Law, Martin; Jaki, Thomas

    2016-04-01

    Multi-arm multi-stage designs can improve the efficiency of the drug-development process by evaluating multiple experimental arms against a common control within one trial. This reduces the number of patients required compared to a series of trials testing each experimental arm separately against control. By allowing for multiple stages experimental treatments can be eliminated early from the study if they are unlikely to be significantly better than control. Using the TAILoR trial as a motivating example, we explore a broad range of statistical issues related to multi-arm multi-stage trials including a comparison of different ways to power a multi-arm multi-stage trial; choosing the allocation ratio to the control group compared to other experimental arms; the consequences of adding additional experimental arms during a multi-arm multi-stage trial, and how one might control the type-I error rate when this is necessary; and modifying the stopping boundaries of a multi-arm multi-stage design to account for unknown variance in the treatment outcome. Multi-arm multi-stage trials represent a large financial investment, and so considering their design carefully is important to ensure efficiency and that they have a good chance of succeeding. PMID:23242385

  11. Some recommendations for multi-arm multi-stage trials

    PubMed Central

    Magirr, Dominic; Law, Martin; Jaki, Thomas

    2012-01-01

    Multi-arm multi-stage designs can improve the efficiency of the drug-development process by evaluating multiple experimental arms against a common control within one trial. This reduces the number of patients required compared to a series of trials testing each experimental arm separately against control. By allowing for multiple stages experimental treatments can be eliminated early from the study if they are unlikely to be significantly better than control. Using the TAILoR trial as a motivating example, we explore a broad range of statistical issues related to multi-arm multi-stage trials including a comparison of different ways to power a multi-arm multi-stage trial; choosing the allocation ratio to the control group compared to other experimental arms; the consequences of adding additional experimental arms during a multi-arm multi-stage trial, and how one might control the type-I error rate when this is necessary; and modifying the stopping boundaries of a multi-arm multi-stage design to account for unknown variance in the treatment outcome. Multi-arm multi-stage trials represent a large financial investment, and so considering their design carefully is important to ensure efficiency and that they have a good chance of succeeding. PMID:23242385

  12. Designing Scalable PGAS Communication Subsystems on Cray Gemini Interconnect

    SciTech Connect

    Vishnu, Abhinav; Daily, Jeffrey A.; Palmer, Bruce J.

    2012-12-26

    The Cray Gemini Interconnect has been recently introduced as a next generation network architecture for building multi-petaflop supercomputers. Cray XE6 systems including LANL Cielo, NERSC Hopper, ORNL Titan and proposed NCSA BlueWaters leverage the Gemini Interconnect as their primary Interconnection network. At the same time, programming models such as the Message Passing Interface (MPI) and Partitioned Global Address Space (PGAS) models such as Unified Parallel C (UPC) and Co-Array Fortran (CAF) have become available on these systems. Global Arrays is a popular PGAS model used in a variety of application domains including hydrodynamics, chemistry and visualization. Global Arrays uses Aggregate Re- mote Memory Copy Interface (ARMCI) as the communication runtime system for Remote Memory Access communication. This paper presents a design, implementation and performance evaluation of scalable and high performance communication subsystems on Cray Gemini Interconnect using ARMCI. The design space is explored and time-space complexities of commu- nication protocols for one-sided communication primitives such as contiguous and uniformly non-contiguous datatypes, atomic memory operations (AMOs) and memory synchronization is presented. An implementation of the proposed design (referred as ARMCI-Gemini) demonstrates the efficacy on communication primitives, application kernels such as LU decomposition and full applications such as Smooth Particle Hydrodynamics (SPH) application.

  13. 47 CFR 64.1401 - Expanded interconnection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... such equipment to connect interconnectors' fiber optic systems or microwave radio transmission... interconnectors' fiber optic systems or microwave radio transmission facilities (where reasonably feasible) with... interconnection of fiber optic facilities, local exchange carriers shall provide: (1) An interconnection point...

  14. 47 CFR 64.1401 - Expanded interconnection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... such equipment to connect interconnectors' fiber optic systems or microwave radio transmission... interconnectors' fiber optic systems or microwave radio transmission facilities (where reasonably feasible) with... interconnection of fiber optic facilities, local exchange carriers shall provide: (1) An interconnection point...

  15. 47 CFR 64.1401 - Expanded interconnection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... such equipment to connect interconnectors' fiber optic systems or microwave radio transmission... interconnectors' fiber optic systems or microwave radio transmission facilities (where reasonably feasible) with... interconnection of fiber optic facilities, local exchange carriers shall provide: (1) An interconnection point...

  16. 47 CFR 64.1401 - Expanded interconnection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... such equipment to connect interconnectors' fiber optic systems or microwave radio transmission... interconnectors' fiber optic systems or microwave radio transmission facilities (where reasonably feasible) with... interconnection of fiber optic facilities, local exchange carriers shall provide: (1) An interconnection point...

  17. 47 CFR 64.1401 - Expanded interconnection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... such equipment to connect interconnectors' fiber optic systems or microwave radio transmission... interconnectors' fiber optic systems or microwave radio transmission facilities (where reasonably feasible) with... interconnection of fiber optic facilities, local exchange carriers shall provide: (1) An interconnection point...

  18. Immortality of Cu damascene interconnects

    NASA Astrophysics Data System (ADS)

    Hau-Riege, Stefan P.

    2002-04-01

    We have studied short-line effects in fully-integrated Cu damascene interconnects through electromigration experiments on lines of various lengths and embedded in different dielectric materials. We compare these results with results from analogous experiments on subtractively-etched Al-based interconnects. It is known that Al-based interconnects exhibit three different behaviors, depending on the magnitude of the product of current density, j, and line length, L: For small values of (jL), no void nucleation occurs, and the line is immortal. For intermediate values, voids nucleate, but the line does not fail because the current can flow through the higher-resistivity refractory-metal-based shunt layers. Here, the resistance of the line increases but eventually saturates, and the relative resistance increase is proportional to (jL/B), where B is the effective elastic modulus of the metallization system. For large values of (jL/B), voiding leads to an unacceptably high resistance increase, and the line is considered failed. By contrast, we observed only two regimes for Cu-based interconnects: Either the resistance of the line stays constant during the duration of the experiment, and the line is considered immortal, or the line fails due to an abrupt open-circuit failure. The absence of an intermediate regime in which the resistance saturates is due to the absence of a shunt layer that is able to support a large amount of current once voiding occurs. Since voids nucleate much more easily in Cu- than in Al-based interconnects, a small fraction of short Cu lines fails even at low current densities. It is therefore more appropriate to consider the probability of immortality in the case of Cu rather than assuming a sharp boundary between mortality and immortality. The probability of immortality decreases with increasing amount of material depleted from the cathode, which is proportional to (jL2/B) at steady state. By contrast, the immortality of Al-based interconnects is

  19. Formation of interconnections to microfluidic devices

    DOEpatents

    Matzke, Carolyn M.; Ashby, Carol I. H.; Griego, Leonardo

    2003-07-29

    A method is disclosed to form external interconnections to a microfluidic device for coupling of a fluid or light or both into a microchannel of the device. This method can be used to form optical or fluidic interconnections to microchannels previously formed on a substrate, or to form both the interconnections and microchannels during the same process steps. The optical and fluidic interconnections are formed parallel to the plane of the substrate, and are fluid tight.

  20. 18 CFR 292.306 - Interconnection costs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Interconnection costs... § 292.306 Interconnection costs. (a) Obligation to pay. Each qualifying facility shall be obligated to pay any interconnection costs which the State regulatory authority (with respect to any...

  1. 47 CFR 90.477 - Interconnected systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Interconnected systems. 90.477 Section 90.477 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Interconnected Systems § 90.477 Interconnected systems. (a) Applicants for new land stations to...

  2. 47 CFR 90.477 - Interconnected systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Interconnected systems. 90.477 Section 90.477 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Interconnected Systems § 90.477 Interconnected systems. (a) Applicants for new land stations to...

  3. 18 CFR 292.306 - Interconnection costs.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Interconnection costs... § 292.306 Interconnection costs. (a) Obligation to pay. Each qualifying facility shall be obligated to pay any interconnection costs which the State regulatory authority (with respect to any...

  4. 18 CFR 292.306 - Interconnection costs.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Interconnection costs... § 292.306 Interconnection costs. (a) Obligation to pay. Each qualifying facility shall be obligated to pay any interconnection costs which the State regulatory authority (with respect to any...

  5. 47 CFR 51.305 - Interconnection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Interconnection. 51.305 Section 51.305 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Additional Obligations of Incumbent Local Exchange Carriers § 51.305 Interconnection. (a) An incumbent LEC shall provide, for the...

  6. 47 CFR 51.305 - Interconnection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Interconnection. 51.305 Section 51.305 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Additional Obligations of Incumbent Local Exchange Carriers § 51.305 Interconnection. (a) An incumbent LEC shall provide, for the...

  7. 47 CFR 51.305 - Interconnection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Interconnection. 51.305 Section 51.305 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Additional Obligations of Incumbent Local Exchange Carriers § 51.305 Interconnection. (a) An incumbent LEC shall provide, for the...

  8. 47 CFR 51.305 - Interconnection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Interconnection. 51.305 Section 51.305 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERCONNECTION Additional Obligations of Incumbent Local Exchange Carriers § 51.305 Interconnection. (a) An incumbent LEC shall provide, for the...

  9. 14 CFR 29.674 - Interconnected controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Interconnected controls. 29.674 Section 29... Interconnected controls. Each primary flight control system must provide for safe flight and landing and operate independently after a malfunction, failure, or jam of any auxiliary interconnected control....

  10. 14 CFR 27.674 - Interconnected controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Interconnected controls. 27.674 Section 27... Interconnected controls. Each primary flight control system must provide for safe flight and landing and operate independently after a malfunction, failure, or jam of any auxiliary interconnected control....

  11. Nonblocking omega network and its topological equivalence with Benes network

    NASA Astrophysics Data System (ADS)

    Ai, Jun; Cao, Mingcui; Li, Zaiguang

    1994-05-01

    Optical interconnection networks have potential uses in parallel processing computers and photonic switching systems. This paper presents the topology of nonblocking omega network (NON) and studies the topological equivalence variety of NON with Benes network by the graph analysis method.

  12. Flexible interconnects for fuel cell stacks

    DOEpatents

    Lenz, David J.; Chung, Brandon W.; Pham, Ai Quoc

    2004-11-09

    An interconnect that facilitates electrical connection and mechanical support with minimal mechanical stress for fuel cell stacks. The interconnects are flexible and provide mechanically robust fuel cell stacks with higher stack performance at lower cost. The flexible interconnects replace the prior rigid rib interconnects with flexible "fingers" or contact pads which will accommodate the imperfect flatness of the ceramic fuel cells. Also, the mechanical stress of stacked fuel cells will be smaller due to the flexibility of the fingers. The interconnects can be one-sided or double-sided.

  13. Interconnects for nanoscale MOSFET technology: a review

    NASA Astrophysics Data System (ADS)

    Chaudhry, Amit

    2013-06-01

    In this paper, a review of Cu/low-k, carbon nanotube (CNT), graphene nanoribbon (GNR) and optical based interconnect technologies has been done. Interconnect models, challenges and solutions have also been discussed. Of all the four technologies, CNT interconnects satisfy most of the challenges and they are most suited for nanometer scale technologies, despite some minor drawbacks. It is concluded that beyond 32 nm technology, a paradigm shift in the interconnect material is required as Cu/low-k interconnects are approaching fundamental limits.

  14. Bodypart Recognition Using Multi-stage Deep Learning.

    PubMed

    Yan, Zhennan; Zhan, Yiqiang; Peng, Zhigang; Liao, Shu; Shinagawa, Yoshihisa; Metaxas, Dimitris N; Zhou, Xiang Sean

    2015-01-01

    Automatic medical image analysis systems often start from identifying the human body part contained in the image; Specifically, given a transversal slice, it is important to know which body part it comes from, namely "slice-based bodypart recognition". This problem has its unique characteristic--the body part of a slice is usually identified by local discriminative regions instead of global image context, e.g., a cardiac slice is differentiated from an aorta arch slice by the mediastinum region. To leverage this characteristic, we design a multi-stage deep learning framework that aims at: (1) discover the local regions that are discriminative to the bodypart recognition, and (2) learn a bodypart identifier based on these local regions. These two tasks are achieved by the two stages of our learning scheme, respectively. In the pre-train stage, a convolutional neural network (CNN) is learned in a multi-instance learning fashion to extract the most discriminative local patches from the training slices. In the boosting stage, the learned CNN is further boosted by these local patches for bodypart recognition. By exploiting the discriminative local appearances, the learned CNN becomes more accurate than global image context-based approaches. As a key hallmark, our method does not require manual annotations of the discriminative local patches. Instead, it automatically discovers them through multi-instance deep learning. We validate our method on a synthetic dataset and a large scale CT dataset (7000+ slices from wholebody CT scans). Our method achieves better performances than state-of-the-art approaches, including the standard CNN. PMID:26221694

  15. Dynamic Model Validation with Governor Deadband on the Eastern Interconnection

    SciTech Connect

    Kou, Gefei; Hadley, Stanton W; Liu, Yilu

    2014-04-01

    This report documents the efforts to perform dynamic model validation on the Eastern Interconnection (EI) by modeling governor deadband. An on-peak EI dynamic model is modified to represent governor deadband characteristics. Simulation results are compared with synchrophasor measurements collected by the Frequency Monitoring Network (FNET/GridEye). The comparison shows that by modeling governor deadband the simulated frequency response can closely align with the actual system response.

  16. Power System Study for Renewable Energy Interconnection in Malaysia

    NASA Astrophysics Data System (ADS)

    Askar, O. F.; Ramachandaramurthy, V. K.

    2013-06-01

    The renewable energy (RE) sector has grown exponentially in Malaysia with the introduction of the Feed-In-Tariff (FIT) by the Ministry of Energy, Green Technology and Water. Photovoltaic, biogas, biomass and mini hydro are among the renewable energy sources which offer a lucrative tariff to incite developers in taking the green technology route. In order to receive the FIT, a developer is required by the utility company to perform a power system analysis which will determine the technical feasibility of an RE interconnection to the utility company's existing grid system. There are a number of aspects which the analysis looks at, the most important being the load flow and fault levels in the network after the introduction of an RE source. The analysis is done by modelling the utility company's existing network and simulating the network with the interconnection of an RE source. The results are then compared to the values before an interconnection is made as well as ensuring the voltage rise or the increase in fault levels do not violate any pre-existing regulations set by the utility company. This paper will delve into the mechanics of performing a load flow analysis and examining the results obtained.

  17. Modeling of Unsteady Three-dimensional Flows in Multistage Machines

    NASA Technical Reports Server (NTRS)

    Hall, Kenneth C.; Pratt, Edmund T., Jr.; Kurkov, Anatole (Technical Monitor)

    2003-01-01

    Despite many years of development, the accurate and reliable prediction of unsteady aerodynamic forces acting on turbomachinery blades remains less than satisfactory, especially when viewed next to the great success investigators have had in predicting steady flows. Hall and Silkowski (1997) have proposed that one of the main reasons for the discrepancy between theory and experiment and/or industrial experience is that many of the current unsteady aerodynamic theories model a single blade row in an infinitely long duct, ignoring potentially important multistage effects. However, unsteady flows are made up of acoustic, vortical, and entropic waves. These waves provide a mechanism for the rotors and stators of multistage machines to communicate with one another. In other words, wave behavior makes unsteady flows fundamentally a multistage (and three-dimensional) phenomenon. In this research program, we have has as goals (1) the development of computationally efficient computer models of the unsteady aerodynamic response of blade rows embedded in a multistage machine (these models will ultimately be capable of analyzing three-dimensional viscous transonic flows), and (2) the use of these computer codes to study a number of important multistage phenomena.

  18. A new topology discovery protocol for multi-ring interconnected resilient packet rings

    NASA Astrophysics Data System (ADS)

    Zhou, Yuli; Zeng, Qingji; Zhao, Zhengfu; Zhang, Zhizhong

    2004-04-01

    Resilient Packet Ring (RPR) is an emerging network architecture and technology designed to meet the requirements of packet-based metropolitan area network (MAN). IEEE 802.17 RPR Draft Standard[1] defines RPR dual-ring topology discovery protocol. In this paper, we propose a new RPR multi-ring interconnected network. RPR multi-ring interconnected network has better resource availability and better bandwidth utilization than RPR dual-ring topology. So how to extend RPR dual-ring topology to RPR multi-ring interconnected network really deserves our attention. RPR multi-ring network is formed by decreasing the scale of standard RPR and interconnecting several small scale standard RPR rings together through cross-stations. The new topology discovery algorithm uses the method of multi-layer subnet topology discovery in clockwise implemented by the multi-ring automatic topology discovery module in cross-station"s MAC control layer. Furthermore, we bring forward the unit structure of tree-like bi-direction list and of topology information list. The paper mainly contains the two parts: RPR standard topology discovery algorithm and RPR multi-ring interconnected topology discovery algorithm.

  19. Multistage Magnetic Separator of Cells and Proteins

    NASA Technical Reports Server (NTRS)

    Barton, Ken; Ainsworth, Mark; Daily, Bruce; Dunn, Scott; Metz, Bill; Vellinger, John; Taylor, Brock; Meador, Bruce

    2005-01-01

    The multistage electromagnetic separator for purifying cells and magnetic particles (MAGSEP) is a laboratory apparatus for separating and/or purifying particles (especially biological cells) on the basis of their magnetic susceptibility and magnetophoretic mobility. Whereas a typical prior apparatus based on similar principles offers only a single stage of separation, the MAGSEP, as its full name indicates, offers multiple stages of separation; this makes it possible to refine a sample population of particles to a higher level of purity or to categorize multiple portions of the sample on the basis of magnetic susceptibility and/or magnetophoretic mobility. The MAGSEP includes a processing unit and an electronic unit coupled to a personal computer. The processing unit includes upper and lower plates, a plate-rotation system, an electromagnet, an electromagnet-translation system, and a capture-magnet assembly. The plates are bolted together through a roller bearing that allows the plates to rotate with respect to each other. An interface between the plates acts as a seal for separating fluids. A lower cuvette can be aligned with as many as 15 upper cuvette stations for fraction collection during processing. A two-phase stepping motor drives the rotation system, causing the upper plate to rotate for the collection of each fraction of the sample material. The electromagnet generates a magnetic field across the lower cuvette, while the translation system translates the electromagnet upward along the lower cuvette. The current supplied to the electromagnet, and thus the magnetic flux density at the pole face of the electromagnet, can be set at a programmed value between 0 and 1,400 gauss (0.14 T). The rate of translation can be programmed between 5 and 2,000 m/s so as to align all sample particles in the same position in the cuvette. The capture magnet can be a permanent magnet. It is mounted on an arm connected to a stepping motor. The stepping motor rotates the arm to

  20. Nested Neural Networks

    NASA Technical Reports Server (NTRS)

    Baram, Yoram

    1992-01-01

    Report presents analysis of nested neural networks, consisting of interconnected subnetworks. Analysis based on simplified mathematical models more appropriate for artificial electronic neural networks, partly applicable to biological neural networks. Nested structure allows for retrieval of individual subpatterns. Requires fewer wires and connection devices than fully connected networks, and allows for local reconstruction of damaged subnetworks without rewiring entire network.

  1. Double interconnection fuel cell array

    DOEpatents

    Draper, Robert; Zymboly, Gregory E.

    1993-01-01

    A fuel cell array (10) is made, containing number of tubular, elongated fuel cells (12) which are placed next to each other in rows (A, B, C, D), where each cell contains inner electrodes (14) and outer electrodes (18 and 18'), with solid electrolyte (16 and 16') between the electrodes, where the electrolyte and outer electrode are discontinuous, having two portions, and providing at least two opposed discontinuities which contain at least two oppositely opposed interconnections (20 and 20') contacting the inner electrode (14), each cell (12) having only three metallic felt electrical connectors (22) which contact surrounding cells, where each row is electrically connected to the other.

  2. Optical transposition transform interconnects using a free-space and fiber hybrid module

    NASA Astrophysics Data System (ADS)

    Popelek, Jan; Li, Yao

    1999-04-01

    Cross-connect switch is a popular switching architecture for telecom and datacom applications. Using various switching components and a k-shuffle interconnect, a cross-connect switch can be configured for general-purpose, blocking as well as non-blocking networking applications. We show that a 1D k-shuffle interconnect pattern is topologically equivalent to a 2D transposition transform pattern. Based on this observation and using space-invariant optical components, the transposition transform interconnect is experimentally implemented. To achieve a sensible packing, we propose to incorporate fiber arrays into the implementation so that the interconnect offers connectorized plug-and-play capability with its switching arrays. Experimental results of implementing a 256 X 256 connectorized free-space and fiber hybrid transposition transform interconnect for cross-connect switching are presented. Key parameters, such as insertion loss, cross- talk, and bit-error-rate of the hybrid interconnect module are measured. Video data are used to demonstrate interconnect quality of various link channels. Scalability to larger interconnects are speculated.

  3. Understanding the Impact of Interconnect Failures on System Operation

    SciTech Connect

    Ezell, Matthew A

    2013-01-01

    Hardware failures are inevitable on large high performance computing systems. Faults or performance degradations in the high-speed network can reduce the entire system s performance. Since the introduction of the Gemini interconnect, Cray systems have become resilient to many networking faults that were fatal in their previous generation systems. These new network reliability and resiliency features have enabled higher uptimes on Cray systems by allowing them to continue running with reduced network performance. Oak Ridge National Laboratory has developed a set of user-level diagnostics that stresses the high-speed network and searches for components that are not performing as expected. Nearest-neighbor bandwidth tests check every network chip and network link in the system. Additionally, performance counters stored on the network ASIC s memory mapped registers (MMRs) are used to better understand the state of the network. Applications have also been characterized under various suboptimal network conditions to better understand what impact network problems have on user codes.

  4. Activated sludge process performance using a multistage tower aeration tank

    SciTech Connect

    Shimizu, Tatsuo; Kudo, Kenzo; Nasu, Yoshikazu )

    1993-07-01

    This study's objective was to clarify both experimentally and theoretically whether a vertical multistage tower aeration tank system is advantageous as compared with a completely mixed system, particularly with respect to purification efficiency, sludge settleability, and excess sludge production. In comparing the two systems: (1) purification efficiency in the multistage tower aeration system with partial fluid mixing with a large Peclet number was higher than in a corresponding completely mixed system for all applied organic loadings; (2) the multistage tower aeration system had some definite advantages with respect to sludge settleability and excess sludge production; and (3) the activated sludge system's higher performance with partial fluid mixing was shown quantitatively with the axial dispersion model in conjunction with growth kinetics which involved rapid uptake such as biosorption and subsequent oxidative biodegradation processes of organic substances.

  5. Conceptual closure. How memories are woven into an interconnected worldview.

    PubMed

    Gabora, L M

    2000-01-01

    This paper describes a tentative model for how discrete memories transform into an interconnected conceptual network, or worldview, wherein relationships between memories are forged by way of abstractions. The model draws on Kauffman's theory of how an information-evolving system can emerge through the formation and closure of an autocatalytic network. Here, the information units are not catalytic molecules, but memories and abstractions, and the process that connects them is not catalysis but reminding events (i.e., one memory evokes another). The result is a worldview that both structures, and is structured by, self-triggered streams of thought. PMID:10818556

  6. An experimental method for directly determining the interconnectivity of melt in a partially molten system

    NASA Technical Reports Server (NTRS)

    Daines, Martha J.; Richter, Frank M.

    1988-01-01

    An experimental method for directly determining the degree of interconnectivity of melt in a partially molten system is discussed using an olivine-basalt system as an example. Samarium 151 is allowed time to diffuse through mixtures of olivine and basalt powder which have texturally equilibrated at 1350 C and 13 to 15 kbars. The final distribution of samarium is determined through examination of developed radiographs of the samples. Results suggest an interconnected melt network is established at melt fractions at least as low as 1 wt pct and all melt is completely interconnected at melt fractions at least as low as 2 wt pct for the system examined.

  7. Optimization of Adaboost Algorithm for Sonar Target Detection in a Multi-Stage ATR System

    NASA Technical Reports Server (NTRS)

    Lin, Tsung Han (Hank)

    2011-01-01

    JPL has developed a multi-stage Automated Target Recognition (ATR) system to locate objects in images. First, input images are preprocessed and sent to a Grayscale Optical Correlator (GOC) filter to identify possible regions-of-interest (ROIs). Second, feature extraction operations are performed using Texton filters and Principal Component Analysis (PCA). Finally, the features are fed to a classifier, to identify ROIs that contain the targets. Previous work used the Feed-forward Back-propagation Neural Network for classification. In this project we investigate a version of Adaboost as a classifier for comparison. The version we used is known as GentleBoost. We used the boosted decision tree as the weak classifier. We have tested our ATR system against real-world sonar images using the Adaboost approach. Results indicate an improvement in performance over a single Neural Network design.

  8. IETI - Isogeometric Tearing and Interconnecting.

    PubMed

    Kleiss, Stefan K; Pechstein, Clemens; Jüttler, Bert; Tomar, Satyendra

    2012-11-01

    Finite Element Tearing and Interconnecting (FETI) methods are a powerful approach to designing solvers for large-scale problems in computational mechanics. The numerical simulation problem is subdivided into a number of independent sub-problems, which are then coupled in appropriate ways. NURBS- (Non-Uniform Rational B-spline) based isogeometric analysis (IGA) applied to complex geometries requires to represent the computational domain as a collection of several NURBS geometries. Since there is a natural decomposition of the computational domain into several subdomains, NURBS-based IGA is particularly well suited for using FETI methods. This paper proposes the new IsogEometric Tearing and Interconnecting (IETI) method, which combines the advanced solver design of FETI with the exact geometry representation of IGA. We describe the IETI framework for two classes of simple model problems (Poisson and linearized elasticity) and discuss the coupling of the subdomains along interfaces (both for matching interfaces and for interfaces with T-joints, i.e. hanging nodes). Special attention is paid to the construction of a suitable preconditioner for the iterative linear solver used for the interface problem. We report several computational experiments to demonstrate the performance of the proposed IETI method. PMID:24511167

  9. Interconnect fatigue design for terrestrial photovoltaic modules

    NASA Technical Reports Server (NTRS)

    Mon, G. R.; Moore, D. M.; Ross, R. G., Jr.

    1982-01-01

    The results of comprehensive investigation of interconnect fatigue that has led to the definition of useful reliability-design and life-prediction algorithms are presented. Experimental data indicate that the classical strain-cycle (fatigue) curve for the interconnect material is a good model of mean interconnect fatigue performance, but it fails to account for the broad statistical scatter, which is critical to reliability prediction. To fill this shortcoming the classical fatigue curve is combined with experimental cumulative interconnect failure rate data to yield statistical fatigue curves (having failure probability as a parameter) which enable (1) the prediction of cumulative interconnect failures during the design life of an array field, and (2) the unambiguous--ie., quantitative--interpretation of data from field-service qualification (accelerated thermal cycling) tests. Optimal interconnect cost-reliability design algorithms are derived based on minimizing the cost of energy over the design life of the array field.

  10. Interconnect fatigue design for terrestrial photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Mon, G. R.; Moore, D. M.; Ross, R. G., Jr.

    1982-03-01

    The results of comprehensive investigation of interconnect fatigue that has led to the definition of useful reliability-design and life-prediction algorithms are presented. Experimental data indicate that the classical strain-cycle (fatigue) curve for the interconnect material is a good model of mean interconnect fatigue performance, but it fails to account for the broad statistical scatter, which is critical to reliability prediction. To fill this shortcoming the classical fatigue curve is combined with experimental cumulative interconnect failure rate data to yield statistical fatigue curves (having failure probability as a parameter) which enable (1) the prediction of cumulative interconnect failures during the design life of an array field, and (2) the unambiguous--ie., quantitative--interpretation of data from field-service qualification (accelerated thermal cycling) tests. Optimal interconnect cost-reliability design algorithms are derived based on minimizing the cost of energy over the design life of the array field.

  11. 47 CFR 90.477 - Interconnected systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Beach, California 34°03′15.0″ 118°14′31.3″ Chicago, Illinois-Northwestern Indiana 41°52′28.1″ 87°38′22.2... 47 Telecommunication 5 2012-10-01 2012-10-01 false Interconnected systems. 90.477 Section 90.477... MOBILE RADIO SERVICES Transmitter Control Interconnected Systems § 90.477 Interconnected systems....

  12. Cascade solar cell having conductive interconnects

    DOEpatents

    Borden, Peter G.; Saxena, Ram R.

    1982-10-26

    Direct ohmic contact between the cells in an epitaxially grown cascade solar cell is obtained by means of conductive interconnects formed through grooves etched intermittently in the upper cell. The base of the upper cell is directly connected by the conductive interconnects to the emitter of the bottom cell. The conductive interconnects preferably terminate on a ledge formed in the base of the upper cell.

  13. Optical interconnect technologies for high-bandwidth ICT systems

    NASA Astrophysics Data System (ADS)

    Chujo, Norio; Takai, Toshiaki; Mizushima, Akiko; Arimoto, Hideo; Matsuoka, Yasunobu; Yamashita, Hiroki; Matsushima, Naoki

    2016-03-01

    The bandwidth of information and communication technology (ICT) systems is increasing and is predicted to reach more than 10 Tb/s. However, an electrical interconnect cannot achieve such bandwidth because of its density limits. To solve this problem, we propose two types of high-density optical fiber wiring for backplanes and circuit boards such as interface boards and switch boards. One type uses routed ribbon fiber in a circuit board because it has the ability to be formed into complex shapes to avoid interfering with the LSI and electrical components on the board. The backplane is required to exhibit high density and flexibility, so the second type uses loose fiber. We developed a 9.6-Tb/s optical interconnect demonstration system using embedded optical modules, optical backplane, and optical connector in a network apparatus chassis. We achieved 25-Gb/s transmission between FPGAs via the optical backplane.

  14. Interconnected microbiomes and resistomes in low-income human habitats.

    PubMed

    Pehrsson, Erica C; Tsukayama, Pablo; Patel, Sanket; Mejía-Bautista, Melissa; Sosa-Soto, Giordano; Navarrete, Karla M; Calderon, Maritza; Cabrera, Lilia; Hoyos-Arango, William; Bertoli, M Teresita; Berg, Douglas E; Gilman, Robert H; Dantas, Gautam

    2016-05-12

    Antibiotic-resistant infections annually claim hundreds of thousands of lives worldwide. This problem is exacerbated by exchange of resistance genes between pathogens and benign microbes from diverse habitats. Mapping resistance gene dissemination between humans and their environment is a public health priority. Here we characterized the bacterial community structure and resistance exchange networks of hundreds of interconnected human faecal and environmental samples from two low-income Latin American communities. We found that resistomes across habitats are generally structured by bacterial phylogeny along ecological gradients, but identified key resistance genes that cross habitat boundaries and determined their association with mobile genetic elements. We also assessed the effectiveness of widely used excreta management strategies in reducing faecal bacteria and resistance genes in these settings representative of low- and middle-income countries. Our results lay the foundation for quantitative risk assessment and surveillance of resistance gene dissemination across interconnected habitats in settings representing over two-thirds of the world's population. PMID:27172044

  15. DEVELOPMENTS IN LIMB (LIMESTONE INJECTION MULTISTAGE BURNER) TECHNOLOGY

    EPA Science Inventory

    The paper describes the most recent results from the Limestone Injection Multistage Burner (LIMB) program, results from the wall-fired demonstration. Tests were conducted to determine the efficacy of commercial calcium hydroxide--Ca(OH)2--supplied by Marblehead Lime Co. and of ca...

  16. MULTISTAGED BURNER DESIGN FOR IN-FURNACE NOX CONTROL

    EPA Science Inventory

    The paper gives results of an evaluation of a multistage combustion modification design, combining two advanced NOx control technologies, on a pilot-scale (0.9 MW) package boiler simulator for in-furnace NOx control of high nitrogen fuel combustion applications. A low NOx precomb...

  17. LOW NOX, HIGH EFFICIENCY MULTISTAGED BURNER: GASEOUS FUEL RESULTS

    EPA Science Inventory

    The paper discusses the evaluation of a multistaged combustion burner design on a 0.6 MW package boiler simulator for in-furnace NOx control and high combustion efficiency. Both deep air staging, resulting in a three-stage configuration, and boiler front wall fuel staging of undo...

  18. The theory of multistage integration in the visual brain.

    PubMed Central

    Bartels, A; Zeki, S

    1998-01-01

    The theory of multistage integration is based on evidence that the visual brain consists of several parallel multistage processing systems, each specialized for a given attribute such as colour or motion. Each stage of a given system processes information at a distinct level of complexity. Our theory supposes that activity at any stage of a given multistage processing system is perceptually explicit--that is to say, it requires no further processing to generate a conscious experience. This activity can be integrated, or bound, with the perceptually explicit activity at any given stage of another or the same multistage processing system. Such binding is therefore not a process that generates a conscious experience, but rather one that brings different conscious experiences together. Many perceptual advantages result from such a flexible and dynamic integrative system. Conversely, there would be disadvantages to limiting perception and binding to hypothetical 'terminal' stages of such processing systems or to hypothetical 'integrator' areas. Although we formulate our hypothesis in terms of the visual brain, we believe it might form a general principle of brain functioning. PMID:9881478

  19. Test Information Targeting Strategies for Adaptive Multistage Testing Designs.

    ERIC Educational Resources Information Center

    Luecht, Richard M.; Burgin, William

    Adaptive multistage testlet (MST) designs appear to be gaining popularity for many large-scale computer-based testing programs. These adaptive MST designs use a modularized configuration of preconstructed testlets and embedded score-routing schemes to prepackage different forms of an adaptive test. The conditional information targeting (CIT)…

  20. Optimal Testlet Pool Assembly for Multistage Testing Designs

    ERIC Educational Resources Information Center

    Ariel, Adelaide; Veldkamp, Bernard P.; Breithaupt, Krista

    2006-01-01

    Computerized multistage testing (MST) designs require sets of test questions (testlets) to be assembled to meet strict, often competing criteria. Rules that govern testlet assembly may dictate the number of questions on a particular subject or may describe desirable statistical properties for the test, such as measurement precision. In an MST…

  1. Low-dose-rate extrapolation using the multistage model

    SciTech Connect

    Portier, C.; Hoel, D.

    1983-12-01

    The distribution of the maximum likelihood estimates of virtually safe levels of exposure to environmental chemicals is derived by using large-sample theory and Monte Carlo simulation according to the Armitage-Doll multistage model. Using historical dose-response we develop a set of 33 two-stage models upon which we base our conclusions. The large-sample distributions of the virtually safe dose are normal for cases in which the multistage-model parameters have nonzero expectation, and are skewed in other cases. The large-sample theory does not provide a good approximation of the distribution observed for small bioassays when Monte Carlo simulation is used. The constrained nature of the multistage-model parameters leads to bimodal distributions for small bioassays. The two modes are the direct result of estimating the linear parameter in the multistage model; the lower mode results from estimating this parameter to be nonzero, and the upper mode from estimating it to be zero. The results of this research emphasize the need for incorporation of the biological theory in the model-selection process.

  2. Young adults' decision making surrounding heavy drinking: a multi-staged model of planned behaviour.

    PubMed

    Northcote, Jeremy

    2011-06-01

    This paper examines the real life contexts in which decisions surrounding heavy drinking are made by young adults (that is, on occasions when five or more alcoholic drinks are consumed within a few hours). It presents a conceptual model that views such decision making as a multi-faceted and multi-staged process. The mixed method study draws on purposive data gathered through direct observation of eight social networks consisting of 81 young adults aged between 18 and 25 years in Perth, Western Australia, including in-depth interviews with 31 participants. Qualitative and some basic quantitative data were gathered using participant observation and in-depth interviews undertaken over an eighteen month period. Participants explained their decision to engage in heavy drinking as based on a variety of factors. These elements relate to socio-cultural norms and expectancies that are best explained by the theory of planned behaviour. A framework is proposed that characterises heavy drinking as taking place in a multi-staged manner, with young adults having: 1. A generalised orientation to the value of heavy drinking shaped by wider influences and norms; 2. A short-term orientation shaped by situational factors that determines drinking intentions for specific events; and 3. An evaluative orientation shaped by moderating factors. The value of qualitative studies of decision making in real life contexts is advanced to complement the mostly quantitative research that dominates research on alcohol decision making. PMID:21632161

  3. Vega rocket series of multi-stage amateur's rocket program 1965-1968

    NASA Astrophysics Data System (ADS)

    Kerstein, Aleksander; Krmelj, Miloš

    2003-08-01

    The Astronautical and Rocket Society of Celje (ARSC — Astronavtično in raketno društvo Celje) Slovenia has been involved in experimental programs for students and adults since early in 1962 when the early maned space flight inspired many young people. In the history of ARSC (1962-1999) many project undergone the period 37 years, but one is significant; the PROJECT MULTISTAGE ROCKETS VEGA. The present paper contains chronological and systematical presentation of most rockets, launching and static tests undergone during the period of 1965-1968. VEGA - III - C launching was viewed by some of 500 participants of XVIII International Astronautic Federation Congress, which was held in Belgrade in the former Yugoslavia at that time. Project VEGA, whose main objecture was solid fuel ≫micrograne≪ motor of 100 mm to 160 mm diameter improvements and interconnecting motors in parallel spree and sequentially in stages has been completed with rocket VEGA - IV. This rocket has never been launched and it is still in storage.

  4. Adaptive optical interconnects: the ADDAPT project

    NASA Astrophysics Data System (ADS)

    Henker, Ronny; Pliva, Jan; Khafaji, Mahdi; Ellinger, Frank; Toifl, Thomas; Offrein, Bert; Cevrero, Alessandro; Oezkaya, Ilter; Seifried, Marc; Ledentsov, Nikolay; Kropp, Joerg-R.; Shchukin, Vitaly; Zoldak, Martin; Halmo, Leos; Turkiewicz, Jaroslaw; Meredith, Wyn; Eddie, Iain; Georgiades, Michael; Charalambides, Savvas; Duis, Jeroen; van Leeuwen, Pieter

    2015-09-01

    Existing optical networks are driven by dynamic user and application demands but operate statically at their maximum performance. Thus, optical links do not offer much adaptability and are not very energy-efficient. In this paper a novel approach of implementing performance and power adaptivity from system down to optical device, electrical circuit and transistor level is proposed. Depending on the actual data load, the number of activated link paths and individual device parameters like bandwidth, clock rate, modulation format and gain are adapted to enable lowering the components supply power. This enables flexible energy-efficient optical transmission links which pave the way for massive reductions of CO2 emission and operating costs in data center and high performance computing applications. Within the FP7 research project Adaptive Data and Power Aware Transceivers for Optical Communications (ADDAPT) dynamic high-speed energy-efficient transceiver subsystems are developed for short-range optical interconnects taking up new adaptive technologies and methods. The research of eight partners from industry, research and education spanning seven European countries includes the investigation of several adaptive control types and algorithms, the development of a full transceiver system, the design and fabrication of optical components and integrated circuits as well as the development of high-speed, low loss packaging solutions. This paper describes and discusses the idea of ADDAPT and provides an overview about the latest research results in this field.

  5. 14 CFR 29.674 - Interconnected controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Interconnected controls. 29.674 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.674 Interconnected controls. Each primary flight control system must provide for safe flight and landing and...

  6. 14 CFR 27.674 - Interconnected controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Interconnected controls. 27.674 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.674 Interconnected controls. Each primary flight control system must provide for safe flight and landing and...

  7. 14 CFR 23.701 - Flap interconnection.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Flap interconnection. 23.701 Section 23.701... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.701 Flap interconnection. (a) The main wing flaps and related movable surfaces as a...

  8. 14 CFR 23.701 - Flap interconnection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flap interconnection. 23.701 Section 23.701... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.701 Flap interconnection. (a) The main wing flaps and related movable surfaces as a...

  9. 14 CFR 23.701 - Flap interconnection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flap interconnection. 23.701 Section 23.701... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.701 Flap interconnection. (a) The main wing flaps and related movable surfaces as a...

  10. 47 CFR 69.124 - Interconnection charge.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Interconnection charge. 69.124 Section 69.124 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) ACCESS CHARGES Computation of Charges § 69.124 Interconnection charge. (a) Until December 31, 2001, local exchange...

  11. 47 CFR 69.124 - Interconnection charge.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Interconnection charge. 69.124 Section 69.124 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) ACCESS CHARGES Computation of Charges § 69.124 Interconnection charge. (a) Until December 31, 2001, local exchange...

  12. Interconnect fatigue design for terrestrial photovoltaic modules

    SciTech Connect

    Mon, G. R.; Moore, D. M.; Ross, Jr., R. G.

    1982-03-01

    Fatigue of solar cell electrical interconnects due to thermal cycling has historically been a major failure mechanism in photovoltaic arrays; the results of a comprehensive investigation of interconnect fatigue that has led to the definition of useful reliability-design and life-prediction algorithms are presented. Experimental data gathered in this study indicate that the classical strain-cycle (fatigue) curve for the interconnect material is a good model of mean interconnect fatigue performance, but it fails to account for the broad statistical scatter, which is critical to reliability prediction. To fill this shortcoming the classical fatigue curve is combined with experimental cumulative interconnect failure rate data to yield statistical fatigue curves (having failure probability as a parameter) which enable: (1) the prediction of cumulative interconnect failures during the design life of an array field; and (2) the unambiguous - i.e., quantitative - interpretation of data from field-service qualification (accelerated thermal cycling) tests. Optimal interconnect cost-reliability design algorithms are derived based on minimizing the cost of energy over the design life of the array field. This procedure yields not only the minimum break-even cost of delivered energy, but also the required degree of interconnect redundancy and an estimate of array power degradation during the design life of the array field. The usefulness of the design algorithms is demonstrated with realistic examples of design optimization, prediction, and service qualification testing.

  13. Updating Technical Screens for PV Interconnection: Preprint

    SciTech Connect

    Coddington, M.; Ellis, A.; Lynn, K.; Razon, A.; Key, T.; Kroposki, B.; Mather, B.; Hill, R.; Nicole, K.; Smith, J.

    2012-08-01

    Solar photovoltaics (PV) is the dominant type of distributed generation (DG) technology interconnected to electric distribution systems in the United States, and deployment of PV systems continues to increase rapidly. Considering the rapid growth and widespread deployment of PV systems in United States electric distribution grids, it is important that interconnection procedures be as streamlined as possible to avoid unnecessary interconnection studies, costs, and delays. Because many PV interconnection applications involve high penetration scenarios, the process needs to allow for a sufficiently rigorous technical evaluation to identify and address possible system impacts. Existing interconnection procedures are designed to balance the need for efficiency and technical rigor for all DG. However, there is an implicit expectation that those procedures will be updated over time in order to remain relevant with respect to evolving standards, technology, and practical experience. Modifications to interconnection screens and procedures must focus on maintaining or improving safety and reliability, as well as accurately allocating costs and improving expediency of the interconnection process. This paper evaluates the origins and usefulness of the capacity penetration screen, offers potential short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen.

  14. 47 CFR 101.519 - Interconnection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Interconnection. 101.519 Section 101.519 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES 24 GHz Service and Digital Electronic Message Service § 101.519 Interconnection. (a) All...

  15. Durability of Metallic Interconnects and Protective Coatings

    SciTech Connect

    Yang, Zhenguo; Stevenson, Jeffry W.

    2009-12-15

    To build up a useful voltage, a number of solid oxide fuel cells (SOFCs) are electrically connected into series in a stack via interconnects, which are placed between adjacent cells. In addition to functioning as a bi-polar electrical connector, the interconnect also acts as a separator plate that separates the fuel at the anode side of one cell from the air at the cathode side on an adjacent cell. During SOFC operation at the high temperatures, the interconnects are thus simultaneously exposed to the oxidizing air at one side and a reducing fuel that can be either hydrogen or hydrocarbon at the other. Besides, they are in contact with adjacent components, such as electrodes or electrical contacts, seals, etc. With steady reduction in SOFC operating temperatures into the low or intermediate range 600-850oC, oxidation resistant alloys are often used to construct interconnects. However, the metallic interconnects may degrade via interactions at their interfaces with surrounding environments or adjacent components, potentially affecting the stability and performance of interconnects and the SOFC stacks. Thus protection layers are applied to metallic interconnects that also intend to mitigate or prevent chromium migration into cells and the cell poisoning. This chapter provides a comprehensive review of materials for metallic interconnects, their degradation and coating protection.

  16. Evaluating the Potential of Cray Gemini Interconnect for PGAS Communication Runtime Systems

    SciTech Connect

    Vishnu, Abhinav; ten Bruggencate, Monika; Olson, Ryan M.

    2011-08-24

    The Cray Gemini Interconnect has been recently introduced as the next generation network for building scalable multi-petascale supercomputers. The Cray XE6 systems, which use the Gemini Interconnect are becoming available with Message Passing Interface (MPI) and Partitioned Global Address Space (PGAS) Models such as as Global Arrays, Unified Parallel C, Co-Array Fortran and Cascade High Performance Language. These PGAS models use one-sided communication runtime systems such as MPI-Remote Memory Access, Aggregate Remote Memory Copy Interface and proprietary communication runtime systems. The primary objective of our work is to study the potential of Cray Gemini Interconnect by designing application specific micro-benchmarks using the DMAPP userspace library provided by the Gemini Interconnect. To meet this objective, we design micro-benchmarks to study the performance of simple communication primitives and application specific micro-benchmarks to understand the behavior of Gemini Interconnect at scale. In our experiments, the Gemini Interconnect can achieve a peak bandwidth of 6911 MB/s and a latency of 1us for get communication primitive. Scalability tests for atomic memory operations and shift communication operation up to 65536 processes shows the efficacy of the Gemini Interconnect.

  17. African electricity infrastructure, interconnections and exchanges

    SciTech Connect

    Hammons, T.J.; Taher, F.; Gulstone, A.B.; Blyden, B.K.; Johnston, R.; Isekemanga, E.; Paluku, K.; Calitz, A.C.; Simanga, N.N.

    1997-01-01

    A 1996 IEEE PES Summer Meeting panel session focused on African Electricity Infrastructure, Interconnections, and Electricity Exchanges. The session was sponsored by the PES Energy Development and Power Generation Committee and organized/moderated by T.J. Hammons, chair of the International Practices Subcommittee. Panelists discussed energy resources, feasibility studies to interconnect power systems, the present state of the electric power sector, future expansion of African power systems, interconnections and power exchanges, and the impact of the private sector on electricity supply. The presentations were as follows: Prospects of the Evolution of a Unified Interconnection Power System in Africa, Fouad Taher; The World Bank`s Involvement with African Electricity Infrastructure, Alfred Gulstone; Towards the implementation of an Integrated African Grid, Bai K. Blyden, Raymond Johnston; Grand Inga Interconnection Projects, Elese Isekemanga, K. Paluku; The Innovative Southern African Kilowatt Hour, Andries C. Calitz; Report on Burundi, Rwanda, and Zaire, Ngove-Ngulu Simanga.

  18. Modeling interconnect corners under double patterning misalignment

    NASA Astrophysics Data System (ADS)

    Hyun, Daijoon; Shin, Youngsoo

    2016-03-01

    Publisher's Note: This paper, originally published on March 16th, was replaced with a corrected/revised version on March 28th. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance. Interconnect corners should accurately reflect the effect of misalingment in LELE double patterning process. Misalignment is usually considered separately from interconnect structure variations; this incurs too much pessimism and fails to reflect a large increase in total capacitance for asymmetric interconnect structure. We model interconnect corners by taking account of misalignment in conjunction with interconnect structure variations; we also characterize misalignment effect more accurately by handling metal pitch at both sides of a target metal independently. Identifying metal space at both sides of a target metal.

  19. Two-Bounce Optical Arbitrary Permutation Network

    NASA Astrophysics Data System (ADS)

    Christensen, Marc P.; Haney, Michael W.

    1998-05-01

    The two-bounce free-space arbitrary interconnection architecture is presented. It results from a series of three-dimensional topological transformations to the Benes network, the minimum rearrangeable nonblocking network. Although functionally equivalent to the Benes network, it requires only two stages of global (spanning multiple chips) optical interconnections. The remaining stages of the modified Benes interconnection network are local and are implemented electronically (on individual chips). The two-bounce network is optimal in the sense that it retains the Benes minimum number of electronic switching resources yet also minimizes the number of optical links needed for global interconnection. Despite the use of higher-order k -shuffle ( k 2 ) global optical interconnects, the number of 2 2 switching elements is identical to the two-shuffle Benes network: there is no need for k k crossbar switches for local interconnection at each stage. An experimental validation of the two-bounce architecture is presented.

  20. Robustness of networks of networks with degree-degree correlation

    NASA Astrophysics Data System (ADS)

    Min, Byungjoon; Canals, Santiago; Makse, Hernan

    Many real-world complex systems ranging from critical infrastructure and transportation networks to living systems including brain and cellular networks are not formed by an isolated network but by a network of networks. Randomly coupled networks with interdependency between different networks may easily result in abrupt collapse. Here, we seek a possible explanation of stable functioning in natural networks of networks including functional brain networks. Specifically, we analyze the robustness of networks of networks focused on one-to-many interconnections between different networks and degree-degree correlation. Implication of the network robustness on functional brain networks of rats is also discussed.

  1. A multistage linear array assignment problem

    NASA Technical Reports Server (NTRS)

    Nicol, David M.; Shier, D. R.; Kincaid, R. K.; Richards, D. S.

    1988-01-01

    The implementation of certain algorithms on parallel processing computing architectures can involve partitioning contiguous elements into a fixed number of groups, each of which is to be handled by a single processor. It is desired to find an assignment of elements to processors that minimizes the sum of the maximum workloads experienced at each stage. This problem can be viewed as a multi-objective network optimization problem. Polynomially-bounded algorithms are developed for the case of two stages, whereas the associated decision problem (for an arbitrary number of stages) is shown to be NP-complete. Heuristic procedures are therefore proposed and analyzed for the general problem. Computational experience with one of the exact problems, incorporating certain pruning rules, is presented with one of the exact problems. Empirical results also demonstrate that one of the heuristic procedures is especially effective in practice.

  2. The high speed interconnect system architecture and operation

    NASA Astrophysics Data System (ADS)

    Anderson, Steven C.

    The design and operation of a fiber-optic high-speed interconnect system (HSIS) being developed to meet the requirements of future avionics and flight-control hardware with distributed-system architectures are discussed. The HSIS is intended for 100-Mb/s operation of a local-area network with up to 256 stations. It comprises a bus transmission system (passive star couplers and linear media linked by active elements) and network interface units (NIUs). Each NIU is designed to perform the physical, data link, network, and transport functions defined by the ISO OSI Basic Reference Model (1982 and 1983) and incorporates a fiber-optic transceiver, a high-speed protocol based on the SAE AE-9B linear token-passing data bus (1986), and a specialized application interface unit. The operating modes and capabilities of HSIS are described in detail and illustrated with diagrams.

  3. Parallel, multi-stage processing of colors, faces and shapes in macaque inferior temporal cortex

    PubMed Central

    Lafer-Sousa, Rosa; Conway, Bevil R.

    2014-01-01

    Visual-object processing culminates in inferior temporal (IT) cortex. To assess the organization of IT, we measured fMRI responses in alert monkey to achromatic images (faces, fruit, bodies, places) and colored gratings. IT contained multiple color-biased regions, which were typically ventral to face patches and, remarkably, yoked to them, spaced regularly at four locations predicted by known anatomy. Color and face selectivity increased for more anterior regions, indicative of a broad hierarchical arrangement. Responses to non-face shapes were found across IT, but were stronger outside color-biased regions and face patches, consistent with multiple parallel streams. IT also contained multiple coarse eccentricity maps: face patches overlapped central representations; color-biased regions spanned mid-peripheral representations; and place-biased regions overlapped peripheral representations. These results suggest that IT comprises parallel, multi-stage processing networks subject to one organizing principle. PMID:24141314

  4. FAST-Net optical interconnection prototype demonstration program

    NASA Astrophysics Data System (ADS)

    Haney, Michael W.; Christensen, Marc P.; Milojkovik, P.; Ekman, Jeremy T.; Chandramani, Premanand; Rozier, Richard G.; Kiamilev, Fouad E.; Liu, Yue; Hibbs-Brenner, Mary K.; Nohava, Jim; Kalweit, Edith; Bounnak, Sommy; Marta, Terry; Walterson, B.

    1998-05-01

    This paper reports progress toward the experimental demonstration of a smart pixel based optical interconnection prototype currently being developed under the Free-space Accelerator for Switching Terabit Networks (FAST-Net) project. The prototype system incorporates 2D arrays of monolithically integrated high- bandwidth vertical cavity surface emitting lasers (VCSELs) and photodetectors (PDs). A key aspect of the FAST-Net concept is that all smart pixels are distributed across a single multi-chip plane. This plane is connected to itself via an optical system that consists of an array of matched lenses (one for each smart pixel chip position) and a mirror. The optical interconnect system implements a global point-to-point shuffle pattern. The interleaved 2D arrays of VCSELs and PDs in the prototype are arranged on a clustered self-similar grid pattern with a closest element pitch of 100 micrometers . The circular VCSEL elements have a diameter of 10 micrometers and the square PDs have an active region that is 50 micrometers wide. These arrays are packaged and mounted on circuit boards along with the CMOS driver, receiver, and FPGA controller chips. Micro-positioning mounts are used to effect alignment that is consistent with current MCM chip placement accuracy. Shuffled optical data links between the multiple ICs have been demonstrated in preliminary evaluation of this system. These results suggest that a multi-Terabit optically interconnected MCM module is feasible.

  5. Power economy using point-to-point optical interconnect links

    NASA Astrophysics Data System (ADS)

    Hartman, Davis H.; Reith, Leslie A.; Habiby, Sarry F.; Lalk, Gail R.; Booth, Bruce L.; Marchegiano, Joseph E.; Hohman, James L.

    1991-04-01

    Future communications networks will be required to provide the switching of very broad-band digita'' channels (typically 155. 52 Mb/s or higher) for as many as 60 customers. Power consumption and cable management are a major factor in the systems level design considerations. It is shown that through the use of ultra-low threshold laser diode arrays optical fiber ribbon cables and a thoughtful packaging strategy significant electrical power advantage can be accrued over conventional electrical interconnection approaches. 1_a

  6. NIRVANA GOSIP (Government Open Systems Interconnect Profile) requirements

    SciTech Connect

    Wood, B.J.

    1990-08-01

    NIRVANA is an effort to standardize electrical computer-aided design workstations at Sandia National Laboratories in Albuquerque, New Mexico. The early effect of this project will be the introduction of at least 60 new engineering workstations at Sandia National Laboratories, Albuquerque, and at Allied Signal, Kansas City Division. These workstations are expected to begin arriving in September 1990. This paper outlines the requirements that a NIRVANA Network must satisfy to comply with the Government Open Systems Interconnect Profile (GOSIP). The author also identifies several issues involved in achieving GOSIP compliance. 4 refs., 1 fig.

  7. Ring-array processor distribution topology for optical interconnects

    NASA Technical Reports Server (NTRS)

    Li, Yao; Ha, Berlin; Wang, Ting; Wang, Sunyu; Katz, A.; Lu, X. J.; Kanterakis, E.

    1992-01-01

    The existing linear and rectangular processor distribution topologies for optical interconnects, although promising in many respects, cannot solve problems such as clock skews, the lack of supporting elements for efficient optical implementation, etc. The use of a ring-array processor distribution topology, however, can overcome these problems. Here, a study of the ring-array topology is conducted with an aim of implementing various fast clock rate, high-performance, compact optical networks for digital electronic multiprocessor computers. Practical design issues are addressed. Some proof-of-principle experimental results are included.

  8. Reentry trajectory optimization based on a multistage pseudospectral method.

    PubMed

    Zhao, Jiang; Zhou, Rui; Jin, Xuelian

    2014-01-01

    Of the many direct numerical methods, the pseudospectral method serves as an effective tool to solve the reentry trajectory optimization for hypersonic vehicles. However, the traditional pseudospectral method is time-consuming due to large number of discretization points. For the purpose of autonomous and adaptive reentry guidance, the research herein presents a multistage trajectory control strategy based on the pseudospectral method, capable of dealing with the unexpected situations in reentry flight. The strategy typically includes two subproblems: the trajectory estimation and trajectory refining. In each processing stage, the proposed method generates a specified range of trajectory with the transition of the flight state. The full glide trajectory consists of several optimal trajectory sequences. The newly focused geographic constraints in actual flight are discussed thereafter. Numerical examples of free-space flight, target transition flight, and threat avoidance flight are used to show the feasible application of multistage pseudospectral method in reentry trajectory optimization. PMID:24574929

  9. Reentry Trajectory Optimization Based on a Multistage Pseudospectral Method

    PubMed Central

    Zhou, Rui; Jin, Xuelian

    2014-01-01

    Of the many direct numerical methods, the pseudospectral method serves as an effective tool to solve the reentry trajectory optimization for hypersonic vehicles. However, the traditional pseudospectral method is time-consuming due to large number of discretization points. For the purpose of autonomous and adaptive reentry guidance, the research herein presents a multistage trajectory control strategy based on the pseudospectral method, capable of dealing with the unexpected situations in reentry flight. The strategy typically includes two subproblems: the trajectory estimation and trajectory refining. In each processing stage, the proposed method generates a specified range of trajectory with the transition of the flight state. The full glide trajectory consists of several optimal trajectory sequences. The newly focused geographic constraints in actual flight are discussed thereafter. Numerical examples of free-space flight, target transition flight, and threat avoidance flight are used to show the feasible application of multistage pseudospectral method in reentry trajectory optimization. PMID:24574929

  10. Multi-staged flap reconstruction for complex radiation thoracic ulcer

    PubMed Central

    Valença-Filipe, Rita; Horta, Ricardo; Costa, Joana; Carvalho, Jorge; Martins, Apolino; Silva, Álvaro

    2014-01-01

    INTRODUCTION Chest wall reconstruction due to previous radiation therapy can be challenging and complex, requiring a multidisciplinary approach. PRESENTATION OF CASE The authors present the case of a 84-year-old woman with a right chest wall radionecrosis ulcer, that was submitted to an ablative surgery resulting in a full-thickness defect of 224 cm2, firstly reconstructed with a pedicled omental flap. Due to partial flap necrosis, other debridements and chest wall multi-staged flap reconstruction were performed. DISCUSSION This case highlights that the reconstructive choice should be individualized and dependent on patient and local factors. The authors advise that surgical team should work closely and be well versed in chest wall reconstruction with a variety of pedicled flaps, when a complication occurs. CONCLUSION A multi-staged flap reconstruction could be a salvage procedure for the coverage of complex, great and complicated chest wall defects due to previous radiation therapy. PMID:25437678

  11. Crosstalk analysis of carbon nanotube bundle interconnects.

    PubMed

    Zhang, Kailiang; Tian, Bo; Zhu, Xiaosong; Wang, Fang; Wei, Jun

    2012-01-01

    Carbon nanotube (CNT) has been considered as an ideal interconnect material for replacing copper for future nanoscale IC technology due to its outstanding current carrying capability, thermal conductivity, and mechanical robustness. In this paper, crosstalk problems for single-walled carbon nanotube (SWCNT) bundle interconnects are investigated; the interconnect parameters for SWCNT bundle are calculated first, and then the equivalent circuit has been developed to perform the crosstalk analysis. Based on the simulation results using SPICE simulator, the voltage of the crosstalk-induced glitch can be reduced by decreasing the line length, increasing the spacing between adjacent lines, or increasing the diameter of SWCNT. PMID:22340628

  12. Gigabit optical interconnects for LAN applications

    NASA Astrophysics Data System (ADS)

    Boncek, Raymond K.; Krol, Mark F.; Johns, Steven T.; Stacy, John L.; Hayduk, Michael J.

    1994-06-01

    We report on the results of experiments performed in areas of technology required to develop gigabit optical interconnects for communication at 1.3 micrometers wavelength. The goal of this work was to develop interconnects not only with very high bandwidth, but with serve to multiple channels having multiple access and simple processing algorithms so as not to rely on high bandwidth electronics, as well. Optical correlation switches (i.e. optical `AND' gates) for use in time-division optical interconnects achieve these goals.

  13. Multi-stage, isothermal CO preferential oxidation reactor

    DOEpatents

    Skala, Glenn William; Brundage, Mark A.; Borup, Rodney Lynn; Pettit, William Henry; Stukey, Kevin; Hart-Predmore, David James; Fairchok, Joel

    2000-01-01

    A multi-stage, isothermal, carbon monoxide preferential oxidation (PrOx) reactor comprising a plurality of serially arranged, catalyzed heat exchangers, each separated from the next by a mixing chamber for homogenizing the gases exiting one heat exchanger and entering the next. In a preferred embodiment, at least some of the air used in the PrOx reaction is injected directly into the mixing chamber between the catalyzed heat exchangers.

  14. Multi-stage depressed collector for small orbit gyrotrons

    DOEpatents

    Singh, A.; Ives, R.L.; Schumacher, R.V.; Mizuhara, Y.M.

    1998-07-14

    A multi-stage depressed collector for receiving energy from a small orbit gyrating electron beam employs a plurality of electrodes at different potentials for sorting the individual electrons on the basis of their total energy level. Magnetic field generating coils, for producing magnetic fields and magnetic iron for magnetic field shaping produce adiabatic and controlled non-adiabatic transitions of the incident electron beam to further facilitate the sorting. 9 figs.

  15. Multi-stage depressed collector for small orbit gyrotrons

    DOEpatents

    Singh, Amarjit; Ives, R. Lawrence; Schumacher, Richard V.; Mizuhara, Yosuke M.

    1998-01-01

    A multi-stage depressed collector for receiving energy from a small orbit gyrating electron beam employs a plurality of electrodes at different potentials for sorting the individual electrons on the basis of their total energy level. Magnetic field generating coils, for producing magnetic fields and magnetic iron for magnetic field shaping produce adiabatic and controlled non-adiabatic transitions of the incident electron beam to further facilitate the sorting.

  16. Multistage aerospace craft. [perspective drawings of conceptual design

    NASA Technical Reports Server (NTRS)

    Kelly, D. L. (Inventor)

    1973-01-01

    A conceptual design of a multi-stage aerospace craft is presented. Two perspective views of the vehicle are developed to show the two component configuration with delta wing, four vertical tail surfaces, tricycle landing gear, and two rocket exhaust nozzles at the rear of the fuselage. Engines for propulsion in the atmosphere are mounted on the fuselage in front of the wing root attachment.

  17. Method for fabricating an interconnected array of semiconductor devices

    DOEpatents

    Grimmer, Derrick P.; Paulson, Kenneth R.; Gilbert, James R.

    1989-10-10

    Semiconductor layer and conductive layer formed on a flexible substrate, divided into individual devices and interconnected with one another in series by interconnection layers and penetrating terminals.

  18. Simulating the multistage environment for single-stage compressor experiments

    SciTech Connect

    Place, J.M.M.; Howard, M.A.; Cumpsty, N.A.

    1996-10-01

    The performance of a single-stage low-speed compressor has been measured both before and after the introduction of certain features of the multistage flow environment. The aim is to make the single-stage rig more appropriate for developing design rules for multistage compressors. End-wall blockage was generated by teeth on the hub and casing upstream of the rotor. A grid fitted upstream produced free-stream turbulence at rotor inlet typical of multistage machines and raised stage efficiency by 1.8 percent at the design point. The potential field that would be generated by blade rows downstream of an embedded stage was replicated by introducing a pressure loss screen at stage exit. This reduced the stator hub corner separation and increased the rotor pressure rise at flow rates below design, changing the shape of the pressure-rise characteristic markedly. These results highlight the importance of features of the flow environment that are often omitted from single-stage experiments and offer improved understanding of stage aerodynamics.

  19. Optical Backplane Interconnect Technology (OBIT)

    NASA Technical Reports Server (NTRS)

    Hammer, J. M.

    1988-01-01

    We describe and analyze a novel approach to implementing an Optical Backplane Interconnect Technology (OBIT) that is capable of optically connecting any row of a 32x32 backplane array to any row of a second 32x32 array. Each backplane array is formed monolithically on a wafer. The technology is based on the use of Grating Surface Emitting (GSE) waveguides formed on a wafer containing quantum-well and separate confinement waveguide layers. These layers are used for transverse guiding, gain, modulation, detection, and for the formation of wavelength tunable distributed-Bragg reflector lasers. The required surface structures are formed photolithographically. The GSE waveguides act as efficient antennae that radiate light at angles selected by tuning the wavelength of the lasers. The same waveguides may be used as the receiving antennae when the array is used in the receiving mode. Thus, wavelength tuning is used to direct each row of the transmitting array to the desired row of the receiving array. In summary: The optical backplane array will have the following characteristics: Any row of a 32x32 GSE array may be optically connected to any row of a second 32x32 array. Only one switch decision is required to switch 32 parallel connections to any one of 32 positions. Each monolithic array can be used as both transmitter and receiver by switching the bias on the quantum-well switch-detectors. Separate transmitting and receiving structures could be provided for duplex operation. For a bit error rate of 10 sup 9 at 100-MHz data rate, a required laser power of 12 mW is calculated based on an estimated total optical loss of 40 dB.

  20. Implementation of optical interconnections for VLSI

    NASA Technical Reports Server (NTRS)

    Wu, Wennie H.; Bergman, Larry A.; Johnston, Alan R.; Guest, Clark C.; Esener, Sadik C.

    1987-01-01

    This paper reports on the progress in implementing optical interconnections for VLSI. Four areas are covered: (1) the holographic optical element (HOE), (2) the laser sources, (3) the detectors and associated circuits forming an optically addressed gate, and (4) interconnection experiments in which five gates are actuated from one source. A laser scanner system with a resolution of 12 x 20 microns has been utilized to generate the HOEs. Diffraction efficiency of the HOE and diffracted spot size have been measured. Stock lasers have been modified with a high-frequency package for interconnect experiments, and buried heterostructure fabrication techniques have been pursued. Measurements have been made on the fabricated photodetectors to determine dark current, responsivity, and response time. The optical gates and the overall chip have been driven successfully with an input light beam, as well as with the optical signal interconnected through the one to five holograms.

  1. INTERCONNECTIONS BETWEEN HUMAN HEALTH AND ECOLOGICAL INTEGRITY

    EPA Science Inventory

    Interconnections between Human Health and Ecological Integrity emanates from a June 2000 Pellston Workshop in Snowbird, Utah, USA. Jointly sponsored by the Society of Environmental Toxicology and Chemistry (SETAC) and the Society of Toxicology (SOT), the workshop was motivated by...

  2. Recent Development of SOFC Metallic Interconnect

    SciTech Connect

    Wu JW, Liu XB

    2010-04-01

    Interest in solid oxide fuel cells (SOFC) stems from their higher e±ciencies and lower levels of emitted pollu- tants, compared to traditional power production methods. Interconnects are a critical part in SOFC stacks, which connect cells in series electrically, and also separate air or oxygen at the cathode side from fuel at the anode side. Therefore, the requirements of interconnects are the most demanding, i:e:, to maintain high elec- trical conductivity, good stability in both reducing and oxidizing atmospheres, and close coe±cient of thermal expansion (CTE) match and good compatibility with other SOFC ceramic components. The paper reviewed the interconnect materials, and coatings for metallic interconnect materials.

  3. Removing Barriers to Utility Interconnected Photovoltaic Inverters

    SciTech Connect

    Gonzalez, S.; Bonn, R.H.; Ginn, J.W.

    2000-10-03

    The Million Solar Roofs Initiative has motivated a renewed interest in the development of utility interconnected photovoltaic (UIPV) inverters. Government-sponsored programs (PVMaT, PVBONUS) and competition among utility interconnected inverter manufacturers have stimulated innovations and improved the performance of existing technologies. With this resurgence, Sandia National Laboratories (SNL) has developed a program to assist industry initiatives to overcome barriers to UIPV inverters. In accordance with newly adopted IEEE 929-2000, the utility interconnected PV inverters are required to cease energizing the utility grid when either a significant disturbance occurs or the utility experiences an interruption in service. Compliance with IEEE 929-2000 is being widely adopted by utilities as a minimum requirement for utility interconnection. This report summarizes work done at the SNL balance-of-systems laboratory to support the development of IEEE 929-2000 and to assist manufacturers in meeting its requirements.

  4. Design of a 12-GHz Multicarrier Earth-Terminal for Satellite-CATV Interconnection.

    ERIC Educational Resources Information Center

    Newman, Burton A.; And Others

    If a satellite-based educational networking and delivery system is to find wide acceptance in the United States and is to be economically viable, it must be capable of interconnecting many headends or nodes on the ground and of delivering quantities of diverse program material. A large number of TV-equivalent bandwidth channels will be required to…

  5. Silicon photonics for compact, energy-efficient interconnects [Invited

    NASA Astrophysics Data System (ADS)

    Barwicz, T.; Byun, H.; Gan, F.; Holzwarth, C. W.; Popovic, M. A.; Rakich, P. T.; Watts, M. R.; Ippen, E. P.; Kã¤Rtner, F. X.; Smith, H. I.; Orcutt, J. S.; Ram, R. J.; Stojanovic, V.; Olubuyide, O. O.; Hoyt, J. L.; Spector, S.; Geis, M.; Grein, M.; Lyszczarz, T.; Yoon, J. U.

    2007-01-01

    The goal of the research program that we describe is to break the emerging performance wall in microprocessor development arising from limited bandwidth and density of on-chip interconnects and chip-to-chip (processor-to-memory) electrical interfaces. Complementary metal-oxide semiconductor compatible photonic devices provide an infrastructure for deployment of a range of integrated photonic networks, which will replace state-of-the-art electrical interconnects, providing significant gains at the system level. Scaling of wavelength-division-multiplexing (WDM) architectures using high-index-contrast (HIC) waveguides offers one path to realizing the energy efficiency and density requirements of high data rate links. HIC microring-resonator filters are well suited to support add-drop nodes in dense WDM photonic networks with high aggregate data rates because they support high Q's and, due to their traveling-wave character, naturally support physically separated input and drop ports. A novel reconfigurable, 'hitless' switch is presented that does not perturb the express channels either before, during, or after reconfiguration. In addition, multigigahertz operation of low-power, Mach-Zehnder silicon modulators as well as germanium-on-silicon photodiodes are presented.

  6. Metallic nanowire networks

    DOEpatents

    Song, Yujiang; Shelnutt, John A.

    2012-11-06

    A metallic nanowire network synthesized using chemical reduction of a metal ion source by a reducing agent in the presence of a soft template comprising a tubular inverse micellar network. The network of interconnected polycrystalline nanowires has a very high surface-area/volume ratio, which makes it highly suitable for use in catalytic applications.

  7. Temperature dependent stability model for graphene nanoribbon interconnects

    NASA Astrophysics Data System (ADS)

    Chanu, Waikhom Mona; Das, Debaprasad

    2016-04-01

    In this paper, a temperature dependent equivalent circuit model for graphene nanoribbon (GNR) interconnects is proposed. The stability analysis of GNR interconnects is performed using this proposed model and its performance is compared with respect to that of the copper based interconnects. The analysis is performed for different interconnect systems for 16nm ITRS technology node. With increase in the length of interconnects, the relative stability increases. GNR interconnect shows less increase of resistance with the increase in temperature as compared to Cu interconnects.

  8. Design and performance of a multi-stage cylindrical reconnection launcher

    SciTech Connect

    Kaye, R.J.; Brawley, E.L.; Duggin, B.W.; Cnare, E.C.; Rovang, D.C.; Widner, M.M. )

    1991-01-01

    A multi-stage, cylindrical reconnection launcher is being tested to demonstrate electrically-contactless, induction-launch technology for solenoidal coil geometry. A 6-stage launcher system is being developed to accelerate a 5 kg mass from rest to 300 m/s with a stored energy of {ge}200 kJ per coil stage. This launcher will provide data fro model verification and the engineering basis for proceeding with larger multistage systems. This paper describes the design of the multi-stage, discrete-coil launcher. Integration of coils, projectile, power systems, and real-time fire control are discussed. Results of multi-stage firings are presented.

  9. Network reliability

    NASA Technical Reports Server (NTRS)

    Johnson, Marjory J.

    1985-01-01

    Network control (or network management) functions are essential for efficient and reliable operation of a network. Some control functions are currently included as part of the Open System Interconnection model. For local area networks, it is widely recognized that there is a need for additional control functions, including fault isolation functions, monitoring functions, and configuration functions. These functions can be implemented in either a central or distributed manner. The Fiber Distributed Data Interface Medium Access Control and Station Management protocols provide an example of distributed implementation. Relative information is presented here in outline form.

  10. Interconnect Performance Evaluation of SGI Altix 3700 BX2, Cray X1, Cray Opteron Cluster, and Dell PowerEdge

    NASA Technical Reports Server (NTRS)

    Fatoohi, Rod; Saini, Subbash; Ciotti, Robert

    2006-01-01

    We study the performance of inter-process communication on four high-speed multiprocessor systems using a set of communication benchmarks. The goal is to identify certain limiting factors and bottlenecks with the interconnect of these systems as well as to compare these interconnects. We measured network bandwidth using different number of communicating processors and communication patterns, such as point-to-point communication, collective communication, and dense communication patterns. The four platforms are: a 512-processor SGI Altix 3700 BX2 shared-memory machine with 3.2 GB/s links; a 64-processor (single-streaming) Cray XI shared-memory machine with 32 1.6 GB/s links; a 128-processor Cray Opteron cluster using a Myrinet network; and a 1280-node Dell PowerEdge cluster with an InfiniBand network. Our, results show the impact of the network bandwidth and topology on the overall performance of each interconnect.

  11. Network congestion can be controlled: Routing algorithms in optical networks and Ethernets

    SciTech Connect

    Goldberg, L.A.; MacKenzie, P.D.; Greenberg, D.S.

    1997-12-01

    Congestion and contention can greatly reduce the effective performance of an interconnection network. This report gathers together research done under a Laboratory Research and Development Program (LDRD) project at Sandia National Laboratories. The goal of the project was to explore the contention properties of novel optical interconnects. In the process of exploring optical interconnects the project also gained new insights into the use of backoff protocols in the current dominant interconnect technology, Ethernet.

  12. Networks.

    ERIC Educational Resources Information Center

    Maughan, George R.; Petitto, Karen R.; McLaughlin, Don

    2001-01-01

    Describes the connectivity features and options of modern campus communication and information system networks, including signal transmission (wire-based and wireless), signal switching, convergence of networks, and network assessment variables, to enable campus leaders to make sound future-oriented decisions. (EV)

  13. Performance of a multistage depressed collector with machined titanium electrodes

    NASA Technical Reports Server (NTRS)

    Ramins, Peter; Ebihara, Ben T.

    1989-01-01

    The performance of a multistage depressed collector (MDC) with machined titanium electrodes was evaluated in conjunction with an 800-W, 8- to 18-GHz travelling-wave tube (TWT) and was compared with the performances of geometrically identical copper and isotropic graphite electrode MDC's operated with the same TWT. The titanium electrode MDC produced a modest (about 3 percent) improvement in the MDC and the TWT overall efficiencies as compared with the copper electrode MDC, but its performance was substantially lower than that of the isotropic graphite electrode MDC.

  14. Multistage spectral relaxation method for solving the hyperchaotic complex systems.

    PubMed

    Saberi Nik, Hassan; Rebelo, Paulo

    2014-01-01

    We present a pseudospectral method application for solving the hyperchaotic complex systems. The proposed method, called the multistage spectral relaxation method (MSRM) is based on a technique of extending Gauss-Seidel type relaxation ideas to systems of nonlinear differential equations and using the Chebyshev pseudospectral methods to solve the resulting system on a sequence of multiple intervals. In this new application, the MSRM is used to solve famous hyperchaotic complex systems such as hyperchaotic complex Lorenz system and the complex permanent magnet synchronous motor. We compare this approach to the Runge-Kutta based ode45 solver to show that the MSRM gives accurate results. PMID:25386624

  15. Thermochemical production of hydrogen via multistage water splitting processes

    NASA Technical Reports Server (NTRS)

    Funk, J. E.

    1975-01-01

    This paper presents and reviews the fundamental thermodynamic principles underlying thermochemical water splitting processes. The overall system is considered first and the temperature limitation in process thermal efficiency is developed. The relationship to an ideal water electrolysis cell is described and the nature of efficient multistage reaction processes is discussed. The importance of the reaction entropy change and the relation of the reaction free energy change to the work of separation is described. A procedure for analyzing thermochemical water splitting processes is presented and its use to calculate individual stage efficiency is demonstrated. A number of processes are used to illustrate the concepts and procedures.

  16. Enhanced decomposition algorithm for multistage stochastic hydroelectric scheduling. Technical report

    SciTech Connect

    Morton, D.P.

    1994-01-01

    Handling uncertainty in natural inflow is an important part of a hydroelectric scheduling model. In a stochastic programming formulation, natural inflow may be modeled as a random vector with known distribution, but the size of the resulting mathematical program can be formidable. Decomposition-based algorithms take advantage of special structure and provide an attractive approach to such problems. We develop an enhanced Benders decomposition algorithm for solving multistage stochastic linear programs. The enhancements include warm start basis selection, preliminary cut generation, the multicut procedure, and decision tree traversing strategies. Computational results are presented for a collection of stochastic hydroelectric scheduling problems. Stochastic programming, Hydroelectric scheduling, Large-scale Systems.

  17. An integral equation solution for multistage turbomachinery design calculations

    NASA Technical Reports Server (NTRS)

    Mcfarland, Eric R.

    1993-01-01

    A method was developed to calculate flows in multistage turbomachinery. The method is an extension of quasi-three-dimensional blade-to-blade solution methods. Governing equations for steady compressible inviscid flow are linearized by introducing approximations. The linearized flow equations are solved using integral equation techniques. The flows through both stationary and rotating blade rows are determined in a single calculation. Multiple bodies can be modelled for each blade row, so that arbitrary blade counts can be analyzed. The method's benefits are its speed and versatility.

  18. Multistage Spectral Relaxation Method for Solving the Hyperchaotic Complex Systems

    PubMed Central

    Saberi Nik, Hassan; Rebelo, Paulo

    2014-01-01

    We present a pseudospectral method application for solving the hyperchaotic complex systems. The proposed method, called the multistage spectral relaxation method (MSRM) is based on a technique of extending Gauss-Seidel type relaxation ideas to systems of nonlinear differential equations and using the Chebyshev pseudospectral methods to solve the resulting system on a sequence of multiple intervals. In this new application, the MSRM is used to solve famous hyperchaotic complex systems such as hyperchaotic complex Lorenz system and the complex permanent magnet synchronous motor. We compare this approach to the Runge-Kutta based ode45 solver to show that the MSRM gives accurate results. PMID:25386624

  19. On the use of ANN interconnection weights in optimal structural design

    NASA Technical Reports Server (NTRS)

    Hajela, P.; Szewczyk, Z.

    1992-01-01

    The present paper describes the use of interconnection weights of a multilayer, feedforward network, to extract information pertinent to the mapping space that the network is assumed to represent. In particular, these weights can be used to determine an appropriate network architecture, and an adequate number of training patterns (input-output pairs) have been used for network training. The weight analysis also provides an approach to assess the influence of each input parameter on a selected output component. The paper shows the significance of this information in decomposition driven optimal design.

  20. The motion of interconnected flexible bodies

    NASA Technical Reports Server (NTRS)

    Hopkins, A. S.

    1975-01-01

    The equations of motion for an arbitrarily interconnected collection of substructures are derived. The substructures are elastic bodies which may be idealized as finite element assemblies and are subject to small deformations relative to a nominal state. Interconnections between the elastic substructures permit large relative translations and rotations between substructures, governed by Pfaffian constraints describing the connections. Screw connections (permitting rotation about and translation along a single axis) eliminate constraint forces and incorporate modal coupling. The problem of flexible spacecraft simulation is discussed. Hurty's component mode approach is extended by permitting interconnected elastic substructures large motions relative to each other and relative to inertial space. The hybrid coordinate methods are generalized by permitting all substructures to be flexible (rather than only the terminal members of a topological tree of substructures). The basic relationships of continuum mechanics are developed.

  1. Interconnection Testing of Distributed Resources: Preprint

    SciTech Connect

    Kroposki, B.; Basso, T.; DeBlasio, R.

    2004-02-01

    With the publication of IEEE 1547-2003(TM) Standard for Interconnecting Distributed Resources With Electric Power Systems, the electric power industry has a need to develop tests and procedures to verify that interconnection equipment meets 1547 technical requirements. A new standard, IEEE P1547.1(TM), is being written to give detailed tests and procedures for confirming that equipment meets the interconnection requirements. The National Renewable Energy Laboratory has been validating test procedures being developed as part of IEEE P1547.1. As work progresses on the validation of those procedures, information and test reports are passed on to the working group of IEEE P1547.1 for future revisions.

  2. Optical transceivers for interconnections in satellite payloads

    NASA Astrophysics Data System (ADS)

    Karppinen, Mikko; Heikkinen, Veli; Juntunen, Eveliina; Kautio, Kari; Ollila, Jyrki; Sitomaniemi, Aila; Tanskanen, Antti

    2013-02-01

    The increasing data rates and processing on board satellites call for the use of photonic interconnects providing high-bitrate performance as well as valuable savings in mass and volume. Therefore, optical transmitter and receiver technology is developed for aerospace applications. The metal-ceramic-packaging with hermetic fiber pigtails enables robustness for the harsh spacecraft environment, while the 850-nm VCSEL-based transceiver technology meets the high bit-rate and low power requirements. The developed components include 6 Gbps SpaceFibre duplex transceivers for intra-satellite data links and 40 Gbps parallel optical transceivers for board-to-board interconnects. Also, integration concept of interchip optical interconnects for onboard processor ICs is presented.

  3. Automotion of domain walls for spintronic interconnects

    SciTech Connect

    Nikonov, Dmitri E.; Manipatruni, Sasikanth; Young, Ian A.

    2014-06-07

    We simulate “automotion,” the transport of a magnetic domain wall under the influence of demagnetization and magnetic anisotropy, in nanoscale spintronic interconnects. In contrast to spin transfer driven magnetic domain wall motion, the proposed interconnects operate without longitudinal charge current transfer, with only a transient current pulse at domain wall creation and have favorable scaling down to the 20 nm dimension. Cases of both in-plane and out-of-plane magnetization are considered. Analytical dependence of the velocity of domain walls on the angle of magnetization are compared with full micromagnetic simulations. Deceleration, attenuation and disappearance, and reflection of domain walls are demonstrated through simulation. Dependences of the magnetization angle on the current pulse parameters are studied. The energy and delay analysis suggests that automotion is an attractive option for spintronic logic interconnects.

  4. Automotion of domain walls for spintronic interconnects

    NASA Astrophysics Data System (ADS)

    Nikonov, Dmitri E.; Manipatruni, Sasikanth; Young, Ian A.

    2014-06-01

    We simulate "automotion," the transport of a magnetic domain wall under the influence of demagnetization and magnetic anisotropy, in nanoscale spintronic interconnects. In contrast to spin transfer driven magnetic domain wall motion, the proposed interconnects operate without longitudinal charge current transfer, with only a transient current pulse at domain wall creation and have favorable scaling down to the 20 nm dimension. Cases of both in-plane and out-of-plane magnetization are considered. Analytical dependence of the velocity of domain walls on the angle of magnetization are compared with full micromagnetic simulations. Deceleration, attenuation and disappearance, and reflection of domain walls are demonstrated through simulation. Dependences of the magnetization angle on the current pulse parameters are studied. The energy and delay analysis suggests that automotion is an attractive option for spintronic logic interconnects.

  5. Laser printing of 3D metallic interconnects

    NASA Astrophysics Data System (ADS)

    Beniam, Iyoel; Mathews, Scott A.; Charipar, Nicholas A.; Auyeung, Raymond C. Y.; Piqué, Alberto

    2016-04-01

    The use of laser-induced forward transfer (LIFT) techniques for the printing of functional materials has been demonstrated for numerous applications. The printing gives rise to patterns, which can be used to fabricate planar interconnects. More recently, various groups have demonstrated electrical interconnects from laser-printed 3D structures. The laser printing of these interconnects takes place through aggregation of voxels of either molten metal or of pastes containing dispersed metallic particles. However, the generated 3D structures do not posses the same metallic conductivity as a bulk metal interconnect of the same cross-section and length as those formed by wire bonding or tab welding. An alternative is to laser transfer entire 3D structures using a technique known as lase-and-place. Lase-and-place is a LIFT process whereby whole components and parts can be transferred from a donor substrate onto a desired location with one single laser pulse. This paper will describe the use of LIFT to laser print freestanding, solid metal foils or beams precisely over the contact pads of discrete devices to interconnect them into fully functional circuits. Furthermore, this paper will also show how the same laser can be used to bend or fold the bulk metal foils prior to transfer, thus forming compliant 3D structures able to provide strain relief for the circuits under flexing or during motion from thermal mismatch. These interconnect "ridges" can span wide gaps (on the order of a millimeter) and accommodate height differences of tens of microns between adjacent devices. Examples of these laser printed 3D metallic bridges and their role in the development of next generation electronics by additive manufacturing will be presented.

  6. Planarization of metal films for multilevel interconnects

    DOEpatents

    Tuckerman, D.B.

    1989-03-21

    In the fabrication of multilevel integrated circuits, each metal layer is planarized by heating to momentarily melt the layer. The layer is melted by sweeping laser pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration. 6 figs.

  7. Graphene Nanoribbons (GNRs) for Future Interconnect

    NASA Astrophysics Data System (ADS)

    Saptono Duryat, Rahmat

    2016-05-01

    Selecting and developing materials for the future devices require a sound understanding of design requirements. Miniaturization of electronic devices, as commonly expressed by Moore Law, has involved the integration level. Increase of the level has caused some consequences in the design and selection of materials for interconnection. The present paper deals with the challenge of materials design and selection beyond the nanoscale limit and the ability of traditional materials to cope with. One of the emerging materials, i.e. Graphene, will be reviewed with particular reference to its characteristics and potentials for future interconnection.

  8. Planarization of metal films for multilevel interconnects

    DOEpatents

    Tuckerman, David B.

    1987-01-01

    In the fabrication of multilevel integrated circuits, each metal layer is anarized by heating to momentarily melt the layer. The layer is melted by sweeping laser pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration.

  9. Planarization of metal films for multilevel interconnects

    DOEpatents

    Tuckerman, David B.

    1989-01-01

    In the fabrication of multilevel integrated circuits, each metal layer is anarized by heating to momentarily melt the layer. The layer is melted by sweeping laser pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration.

  10. Planarization of metal films for multilevel interconnects

    DOEpatents

    Tuckerman, D.B.

    1985-08-23

    In the fabrication of multilevel integrated circuits, each metal layer is planarized by heating to momentarily melt the layer. The layer is melted by sweeping laser pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration.

  11. Planarization of metal films for multilevel interconnects

    DOEpatents

    Tuckerman, D.B.

    1985-06-24

    In the fabrication of multilevel integrated circuits, each metal layer is planarized by heating to momentarily melt the layer. The layer is melted by sweeping lase pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration.

  12. Network Leadership: An Emerging Practice

    ERIC Educational Resources Information Center

    Tremblay, Christopher W.

    2012-01-01

    Network leadership is an emerging approach that can have an impact on change in education and in society. According to Merriam-Webster (2011), a network is "an interconnected or interrelated chain, group, or system." Intentional interconnectedness is what separates network leadership from other leadership theories. Network leadership has the…

  13. Separation Control in a Multistage Compressor Using Impulsive Surface Injection

    NASA Technical Reports Server (NTRS)

    Wundrow, David W.; Braunscheidel, Edward P.; Culley, Dennis E.; Bright, Michelle M.

    2006-01-01

    Control of flow separation using impulsive surface injection is investigated within the multistage environment of a low speed axial-flow compressor. Measured wake profiles behind a set of embedded stator vanes treated with suction-surface injection indicate significant reduction in flow separation at a variety of injection-pulse repetition rates and durations. The corresponding total pressure losses across the vanes reveal a bank of repetition rates at each pulse duration where the separation control remains nearly complete. This persistence allows for demands on the injected-mass delivery system to be economized while still achieving effective flow control. The response of the stator-vane boundary layers to infrequently applied short injection pulses is described in terms of the periodic excitation of turbulent strips whose growth and propagation characteristics dictate the lower bound on the band of optimal pulse repetition rates. The eventual falloff in separation control at higher repetition rates is linked to a competition between the benefits of pulse-induced mixing and the aggravation caused by the periodic introduction of low-momentum fluid. Use of these observations for impulsive actuator design is discussed and their impact on modeling the time-average effect of impulsive surface injection for multistage steady-flow simulation is considered.

  14. A multistaged automatic restoration of noisy microscopy cell images.

    PubMed

    Xu, Jinwei; Hu, Jiankun; Jia, Xiuping

    2015-01-01

    Automated cell segmentation for microscopy cell images has recently become an initial step for further image analysis in cell biology. However, microscopy cell images are easily degraded by noise during the readout procedure via optical-electronic imaging systems. Such noise degradations result in low signal-to-noise ratio (SNR) and poor image quality for cell identification. In order to improve SNR for subsequent segmentation and image-based quantitative analysis, the commonly used state-of-art restoration techniques are applied but few of them are suitable for corrupted microscopy cell images. In this paper, we propose a multistaged method based on a novel integration of trend surface analysis, quantile-quantile plot, bootstrapping, and the Gaussian spatial kernel for the restoration of noisy microscopy cell images. We show this multistaged approach achieves higher performance compared with other state-of-art restoration techniques in terms of peak signal-to-noise ratio and structure similarity in synthetic noise experiments. This paper also reports an experiment on real noisy microscopy data which demonstrated the advantages of the proposed restoration method for improving segmentation performance. PMID:25291801

  15. Pipelining performance of structured dataflow networks

    SciTech Connect

    Tonge, F.M.

    1983-01-01

    A particular approach to specifying procedure interconnection and allocation is presented. The major result is that, within stated assumptions, networks constructed using a small set of structured process connectives can achieve at least as good throughput (pipelining performance) as arbitrarily interconnected networks. 20 references.

  16. Advances in integrated photonic circuits for packet-switched interconnection

    NASA Astrophysics Data System (ADS)

    Williams, Kevin A.; Stabile, Ripalta

    2014-03-01

    Sustained increases in capacity and connectivity are needed to overcome congestion in a range of broadband communication network nodes. Packet routing and switching in the electronic domain are leading to unsustainable energy- and bandwidth-densities, motivating research into hybrid solutions: optical switching engines are introduced for massive-bandwidth data transport while the electronic domain is clocked at more modest GHz rates to manage routing. Commercially-deployed optical switching engines using MEMS technologies are unwieldy and too slow to reconfigure for future packet-based networking. Optoelectronic packet-compliant switch technologies have been demonstrated as laboratory prototypes, but they have so far mostly used discretely pigtailed components, which are impractical for control plane development and product assembly. Integrated photonics has long held the promise of reduced hardware complexity and may be the critical step towards packet-compliant optical switching engines. Recently a number of laboratories world-wide have prototyped optical switching circuits using monolithic integration technology with up to several hundreds of integrated optical components per chip. Our own work has focused on multi-input to multi-output switching matrices. Recently we have demonstrated 8×8×8λ space and wavelength selective switches using gated cyclic routers and 16×16 broadband switching chips using monolithic multi-stage networks. We now operate these advanced circuits with custom control planes implemented with FPGAs to explore real time packet routing in multi-wavelength, multi-port test-beds. We review our contributions in the context of state of the art photonic integrated circuit technology and packet optical switching hardware demonstrations.

  17. Interaction of frequency-modulated light beams in multistage parametric amplifiers at the maximum gain bandwidth

    SciTech Connect

    Vlasov, Sergei N; Koposova, E V; Freidman, Gennadii I

    2009-05-31

    Conditions of the applicability of equations in the quasi-static approximation for studying the parametric interaction of frequency-modulated light beams in multistage amplifiers are considered. This approximation is used to simulate numerically processes in a multistage DKDP crystal amplifier with the output power exceeding 10 PW and suppressed luminescence. (lasers and amplifiers)

  18. Performance of the butterfly processor-memory interconnection in a vector environment

    NASA Astrophysics Data System (ADS)

    Brooks, E. D., III

    1985-02-01

    A fundamental hurdle impeding the development of large N common memory multiprocessors is the performance limitation in the switch connecting the processors to the memory modules. Multistage networks currently considered for this connection have a memory latency which grows like (ALPHA)log2N*. For scientific computing, it is natural to look for a multiprocessor architecture that will enable the use of vector operations to mask memory latency. The problem to be overcome here is the chaotic behavior introduced by conflicts occurring in the switch. The performance of the butterfly or indirect binary n-cube network in a vector processing environment is examined. A simple modification of the standard 2X2 switch node used in such networks which adaptively removes chaotic behavior during a vector operation is described.

  19. Optical interconnections to focal plane arrays

    SciTech Connect

    Rienstra, J.L.; Hinckley, M.K.

    2000-11-01

    The authors have successfully demonstrated an optical data interconnection from the output of a focal plane array to the downstream data acquisition electronics. The demonstrated approach included a continuous wave laser beam directed at a multiple quantum well reflectance modulator connected to the focal plane array analog output. The output waveform from the optical interconnect was observed on an oscilloscope to be a replica of the input signal. They fed the output of the optical data link to the same data acquisition system used to characterize focal plane array performance. Measurements of the signal to noise ratio at the input and output of the optical interconnection showed that the signal to noise ratio was reduced by a factor of 10 or more. Analysis of the noise and link gain showed that the primary contributors to the additional noise were laser intensity noise and photodetector receiver noise. Subsequent efforts should be able to reduce these noise sources considerably and should result in substantially improved signal to noise performance. They also observed significant photocurrent generation in the reflectance modulator that imposes a current load on the focal plane array output amplifier. This current loading is an issue with the demonstrated approach because it tends to negate the power saving feature of the reflectance modulator interconnection concept.

  20. Laser printed interconnects for flexible electronics

    NASA Astrophysics Data System (ADS)

    Pique, Alberto; Beniam, Iyoel; Mathews, Scott; Charipar, Nicholas

    Laser-induced forward transfer (LIFT) can be used to generate microscale 3D structures for interconnect applications non-lithographically. The laser printing of these interconnects takes place through aggregation of voxels of either molten metal or dispersed metallic nanoparticles. However, the resulting 3D structures do not achieve the bulk conductivity of metal interconnects of the same cross-section and length as those formed by wire bonding or tab welding. It is possible, however, to laser transfer entire structures using a LIFT technique known as lase-and-place. Lase-and-place allows whole components and parts to be transferred from a donor substrate onto a desired location with one single laser pulse. This talk will present the use of LIFT to laser print freestanding solid metal interconnects to connect individual devices into functional circuits. Furthermore, the same laser can bend or fold the thin metal foils prior to transfer, thus forming compliant 3D structures able to provide strain relief due to flexing or thermal mismatch. Examples of these laser printed 3D metallic bridges and their role in the development of next generation flexible electronics by additive manufacturing will be presented. This work was funded by the Office of Naval Research (ONR) through the Naval Research Laboratory Basic Research Program.

  1. 14 CFR 23.701 - Flap interconnection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flap interconnection. 23.701 Section 23.701 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.701 Flap...

  2. Electromigration of damascene copper of IC interconnect

    NASA Astrophysics Data System (ADS)

    Meyer, William Kevin

    Copper metallization patterned with multi-level damascene process is prone to electromigration failure, which affects the reliability and performance of IC interconnect. In typical products, interconnect that is not already constrained by I·R drop or Joule self-heating operates at 'near threshold' conditions. Measurement of electromigration damage near threshold is very difficult due to slow degradation requiring greatly extended stress times, or high currents that cause thermal anomalies. Software simulations of the electromigration mechanism combined with characterization of temperature profiles allows extracting material parameters and calculation of design rules to ensure reliable interconnect. Test structures capable of demonstrating Blech threshold effects while allowing thermal characterization were designed and processed. Electromigration stress tests at various conditions were performed to extract both shortline (threshold) and long-line (above threshold) performance values. The resistance increase time constant shows immortality below Je·L (product of current density and segment length) of 3200 amp/cm. Statistical analysis of times-to-failure show that long lines last 105 hours at 3.1 mA/mum2 (120°C). While this is more robust than aluminum interconnect, the semiconductor industry will be challenged to improve that performance as future products require.

  3. 14 CFR 23.701 - Flap interconnection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Flap interconnection. 23.701 Section 23.701 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.701 Flap...

  4. Healing Voids In Interconnections In Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Cuddihy, Edward F.; Lawton, Russell A.; Gavin, Thomas

    1989-01-01

    Unusual heat treatment heals voids in aluminum interconnections on integrated circuits (IC's). Treatment consists of heating IC to temperature between 200 degrees C and 400 degrees C, holding it at that temperature, and then plunging IC immediately into liquid nitrogen. Typical holding time at evaluated temperature is 30 minutes.

  5. A continuum model for interconnected lattice trusses

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1992-01-01

    A continuum model for interconnected lattice trusses based on the 1D Timoshenko beam approximation is developed using the NASA-LRC Phase Zero Evolutionary Model. The continuum model dynamics is presented in the canonical wave-equation form in a Hilbert space.

  6. Vector Lyapunov Functions for Stochastic Interconnected Systems

    NASA Technical Reports Server (NTRS)

    Boussalis, D.

    1985-01-01

    Theoretical paper presents set of sufficient conditions for asymptotic and exponential stability with probability 1 for class of stochastic interconnected systems. Theory applicable to complicated, large-scale mechanical or electrical systems, and, for several design problems, it reduces computational difficulty by relating stability criteria to fundamental structural features of system.

  7. Networking.

    ERIC Educational Resources Information Center

    Duvall, Betty

    Networking is an information giving and receiving system, a support system, and a means whereby women can get ahead in careers--either in new jobs or in current positions. Networking information can create many opportunities: women can talk about how other women handle situations and tasks, and previously established contacts can be used in…

  8. Formation of interconnected morphologies via nanorod inclusion in the confined assembly of symmetric block copolymers.

    PubMed

    Park, Jay Hoon; Joo, Yong Lak

    2014-05-21

    We have investigated the effect of nanorods on the symmetry breaking of a model diblock copolymer under cylindrical confinement using coarse-grained molecular dynamics. Unlike nanoparticles, nanorods can readily be interconnected with each other and also induce connection across self-assembly domains at much lower loading than nanoparticles. Such interconnecting nanorods, when incorporated within the nanofiber confined assembled block copolymer, have great potential for providing highly conductive pathways for energy applications, such as battery electrodes and separators. Symmetric block copolymers (BCP) under cylindrical confinement with a nanorod aspect ratio (N) of 1, 5, and 10 are examined with three different types of nanorod-BCP attractions: (a) neutral nanorods, (b) A (wall-attractive phase)-attractive nanorods, and (c) B (wall-repulsive phase)-attractive nanorods. The system was studied with both selective and neutral walls, which affect the orientation of the interconnected nanorod network. Upon close examination of the BCP-nanorod self-assembly, we discovered that the ratio of the interphase distance to the nanorod aspect ratio (I/N) can be correlated to the onset of nanorod interconnectivity and formation of asymmetrical interconnected BCP morphology. By developing a phase diagram with respect to I/N, one can predict the formation of desired BCP morphology and the critical loading of nanorods for connected morphologies in cylindrical confinement. PMID:24682243

  9. Novel on chip-interconnection structures for giga-scale integration VLSI ICS

    NASA Astrophysics Data System (ADS)

    Nelakuditi, Usha R.; Reddy, S. N.

    2013-01-01

    Based on the guidelines of International Technology Roadmap for Semiconductors (ITRS) Intel has already designed and manufactured the next generation product of the Itanium family containing 1.72 billion transistors. In each new technology due to scaling, individual transistors are becoming smaller and faster, and are dissipating low power. The main challenge with these systems is wiring of these billion transistors since wire length interconnect scaling increases the distributed resistance-capacitance product. In addition, high clock frequencies necessitate reverse scaling of global and semi-global interconnects so that they satisfy the timing constraints. Hence, the performances of future GSI systems will be severely restricted by interconnect performance. It is therefore essential to look at interconnect design techniques that will reduce the impact of interconnect networks on the power, performance and cost of the entire system. In this paper a new routing technique called Wave-Pipelined Multiplexed (WPM) Routing similar to Time Division Multiple Access (TDMA) is discussed. This technique is highly useful for the current high density CMOS VLSI ICs. The major advantages of WPM routing technique are flexible, robust, simple to implement, and realized with low area, low power and performance overhead requirements.

  10. Copper metallization for on-chip interconnects

    NASA Astrophysics Data System (ADS)

    Gelatos, A. V.; Nguyen, Bich-Yen; Perry, Kathleen A.; Marsh, R.; Peschke, J.; Filipiak, Stanley M.; Travis, Edward O.; Thompson, Matthew A.; Saaranen, T.; Tobin, Phil J.; Mogab, C. J.

    1996-09-01

    Continued dimensional scaling of the elements of integrated circuits places significant restrictions on the width, density and current carrying capability of metallic interconnects. It is expected that, by the year 2000, the transistor channel length will be at 0.l8piri [1], while microprocessors will pack more than 15 million transistors over an area of '-700mm2. To conserve area, interconnects will continue to be stacked at an increasing number of levels (6 by the year 2000, vs 4 in todays leading microprocessors) and the minimum spacing and width within an interconnect layer will shrink to 0.3.tm. In addition, it is expected that future interconnects will need to sustain increasingly higher current densities without electromigration failures [2]. Aluminum alloys are the conductors of choice in present-day interconnects, and much effort is focused n means to extend the usefulness of aluminum through improvements in reliability, either by new alloy formulations [3], or by the development of complicated multimetal stacks [4. A more radical approach, which is gaining increased attention, is the replacement of aluminum altogether by copper. The bulk resistivity of copper is significantly lower than that of aluminum (1.7.tW-cm for Cu vs. 3.0iW-cm for Al-Cu), which is expected to translate to interconnects of higher performance because of reduction in signal propagation delay. In addition, the significantly higher melting temperature of copper (.-1100°C vs. -600°C for Al-Cu alloys) and its higher atomic weight are expected to translate to improved resistance to electromigration [5]. However, as with any new process trying to break into the mainstream, significant improvement in reliability and performance over that achievable with aluminum alloys must be demonstrated first. Towards this purpose, processes need to be developed that deposit conformal copper films of high purity with acceptable throughput, and integration schemes need to be developed which produce

  11. Probabilistic immortality of Cu damascene interconnects

    NASA Astrophysics Data System (ADS)

    Hau-Riege, Stefan P.

    2002-02-01

    We have studied electromigration short-line effects in Cu damascene interconnects through experiments on lines of various lengths L, stressed at a variety of current densities j, and embedded in different dielectric materials. We observed two modes of resistance evolution: Either the resistance of the lines remains constant for the duration of the test, so that the lines are considered immortal, or the lines fail due to abrupt open-circuit failure. The resistance was not observed to gradually increase and then saturate, as commonly observed in Al-based interconnects, because the barrier is too thin and resistive to serve as a redundant current path should voiding occur. The critical stress for void nucleation was found to be smaller than 41 MPa, since voiding occurred even under the mildest test conditions of j=2 MA/cm2 and L=10.5 μm at 300 °C. A small fraction of short Cu lines failed even at low current densities, which deems necessary a concept of probabilistic immortality rather than deterministic immortality. Experiments and modeling suggest that the probability of immortality is described by (jL2/B), where B is the effective elastic modulus of the metallization scheme. By contrast, the immortality of Al-based interconnects with shunt layers is described by (jL) if no voids nucleate, and (jL/B) if voids do nucleate. Even though the phenomenology of short-line effects differs for Al- and Cu-based interconnects, the immortality of interconnects of either materials system can be explained by the phenomena of nucleation barriers for void formation and void-growth saturation. The differences are due solely to the absence of a shunt layer and the low critical stress for void nucleation in the case of Cu.

  12. Eating on an interconnected planet

    NASA Astrophysics Data System (ADS)

    MacDonald, Graham K.

    2013-06-01

    Calls to boost agricultural production in order to meet the demands of a growing global population are now commonplace. Yet, depending on where productivity changes and population growth occur, international trade could be increasingly necessary in the transfer of food from farms to consumers. Fader et al (2013) offer a nuanced view of this spatial disconnect and its food security implications by considering a valuable thought experiment: what countries could foreseeably meet their food requirements from internal production alone circa 2000 and for contrasting scenarios in 2050? They investigate the extent to which available renewable water and land resources constrain domestic per capita crop production, assuming current as well as broadly improved yields. The findings convey an intuitive, though often overlooked, point that population growth is likely to increase the reliance of certain regions on food imports unless substantial productivity improvements are realized. It is unlikely that any nation would be compelled to produce all of its food domestically, but reflecting on potential food self-sufficiency is a worthwhile endeavor. Importing crops may be matter of choice, but also one of necessity if available land, water, and yields limit production. Dependence on food imports can involve uncertainty: production shortfalls arising from drought and other factors have been associated with price volatility—or even restrictions on crop exports—posing challenges to countries anticipating consistent import arrangements (Headey 2011). Compounding this uncertainty is that a relatively small number of countries produce the bulk of staple crops for global markets. Just eight countries comprising 11% of the global population produced, on average, 70% of cereal exports during the past decade (FAO 2013). Although trade networks are dynamic, some net-importing countries have developed entrenched relationships with particular producers that entail very large crop transfers

  13. Interconnect assembly for an electronic assembly and assembly method therefor

    DOEpatents

    Gerbsch, Erich William

    2003-06-10

    An interconnect assembly and method for a semiconductor device, in which the interconnect assembly can be used in lieu of wirebond connections to form an electronic assembly. The interconnect assembly includes first and second interconnect members. The first interconnect member has a first surface with a first contact and a second surface with a second contact electrically connected to the first contact, while the second interconnect member has a flexible finger contacting the second contact of the first interconnect member. The first interconnect member is adapted to be aligned and registered with a semiconductor device having a contact on a first surface thereof, so that the first contact of the first interconnect member electrically contacts the contact of the semiconductor device. Consequently, the assembly method does not require any wirebonds, but instead merely entails aligning and registering the first interconnect member with the semiconductor device so that the contacts of the first interconnect member and the semiconductor device make electrically contact, and then contacting the second contact of the first interconnect member with the flexible finger of the second interconnect member.

  14. Silicon Modulators, Switches and Sub-systems for Optical Interconnect

    NASA Astrophysics Data System (ADS)

    Li, Qi

    Silicon photonics is emerging as a promising platform for manufacturing and integrating photonic devices for light generation, modulation, switching and detection. The compatibility with existing CMOS microelectronic foundries and high index contrast in silicon could enable low cost and high performance photonic systems, which find many applications in optical communication, data center networking and photonic network-on-chip. This thesis first develops and demonstrates several experimental work on high speed silicon modulators and switches with record performance and novel functionality. A 8x40 Gb/s transmitter based on silicon microrings is first presented. Then an end-to-end link using microrings for Binary Phase Shift Keying (BPSK) modulation and demodulation is shown, and its performance with conventional BPSK modulation/ demodulation techniques is compared. Next, a silicon traveling-wave Mach- Zehnder modulator is demonstrated at data rate up to 56 Gb/s for OOK modulation and 48 Gb/s for BPSK modulation, showing its capability at high speed communication systems. Then a single silicon microring is shown with 2x2 full crossbar switching functionality, enabling optical interconnects with ultra small footprint. Then several other experiments in the silicon platform are presented, including a fully integrated in-band Optical Signal to Noise Ratio (OSNR) monitor, characterization of optical power upper bound in a silicon microring modulator, and wavelength conversion in a dispersion-engineered waveguide. The last part of this thesis is on network-level application of photonics, specically a broadcast-and-select network based on star coupler is introduced, and its scalability performance is studied. Finally a novel switch architecture for data center networks is discussed, and its benefits as a disaggregated network are presented.

  15. Eating on an interconnected planet

    NASA Astrophysics Data System (ADS)

    MacDonald, Graham K.

    2013-06-01

    Calls to boost agricultural production in order to meet the demands of a growing global population are now commonplace. Yet, depending on where productivity changes and population growth occur, international trade could be increasingly necessary in the transfer of food from farms to consumers. Fader et al (2013) offer a nuanced view of this spatial disconnect and its food security implications by considering a valuable thought experiment: what countries could foreseeably meet their food requirements from internal production alone circa 2000 and for contrasting scenarios in 2050? They investigate the extent to which available renewable water and land resources constrain domestic per capita crop production, assuming current as well as broadly improved yields. The findings convey an intuitive, though often overlooked, point that population growth is likely to increase the reliance of certain regions on food imports unless substantial productivity improvements are realized. It is unlikely that any nation would be compelled to produce all of its food domestically, but reflecting on potential food self-sufficiency is a worthwhile endeavor. Importing crops may be matter of choice, but also one of necessity if available land, water, and yields limit production. Dependence on food imports can involve uncertainty: production shortfalls arising from drought and other factors have been associated with price volatility—or even restrictions on crop exports—posing challenges to countries anticipating consistent import arrangements (Headey 2011). Compounding this uncertainty is that a relatively small number of countries produce the bulk of staple crops for global markets. Just eight countries comprising 11% of the global population produced, on average, 70% of cereal exports during the past decade (FAO 2013). Although trade networks are dynamic, some net-importing countries have developed entrenched relationships with particular producers that entail very large crop transfers

  16. Global interconnectivity in the next two decades - A scenario

    NASA Technical Reports Server (NTRS)

    Lovell, R.; Cuccia, C. L.

    1986-01-01

    The present paper provides a description of a part of NASA's current long range plans, taking into account the development of hierarchal space switching centers and laser intersatellite links which can interconnect the globe. It is pointed out that a special objective involves the development of technology and satellite architecture for reducing the cost of an end-to-end voice message per minute from the present average value of around $.40 now realized by terrestrial telephone systems to less than $.10. The next decade of NASA communications activity (1985-1995) is discussed, giving attention to the Advanced Communications Technology Satellite ACTS (July 1984) which will test the technology of space switchboard and signal processing in space. The environment of the decade 1985-1995 is considered along with the roles of communications satellites, the hierarchies of terrestrial public switched networks, cost comparisons of terrestrial and space point-to-point links, and concomitant technology developments related to supercomputers.

  17. The interconnected data directory system and Catalog Interoperability

    NASA Technical Reports Server (NTRS)

    Thieman, James R.

    1991-01-01

    The Catalog Interoperability (CI) project, designed to enable rapid and efficient identification, location, and access to data of interest to the science community, is considered. The CI goal is to create a worldwide data information network composed of interconnected directory, guide (catalog), and inventory systems. Directories were created to aid in finding data. The directories contain brief information about the data sets, sufficient for determining whether further investigation is warranted. They also provide automated links to other information systems which give more detail on data of interest. A common format for describing data sets has been developed, called the Directory Interchange Format (DIF), which is used as the basis of information to be shared among the directories. These DIF files can be passed among the directories to keep their information up to date.

  18. A Multi-Stage Continuous-Duty Adiabatic Demagnetization Refrigerator

    NASA Technical Reports Server (NTRS)

    Shirron, P. J.; Blumenstock, K. A.; Canavan, E. R.; DiPirro, M. J.; Tuttle, J. G.; Voellmer, G. M.; Yeager, C. J.

    1999-01-01

    The design for a multi-stage adiabatic demagnetization refrigerator (ADR) that can provide continuous cooling at very low temperatures is presented. The ADR is being developed for use in x-ray, IR and sub-millimeter space astronomy missions which will employ large format detector arrays operating at 50 mK and lower and which may dissipate up to 10 microwatts. It is also being designed to reject heat slowly to a relatively warm heat sink (in the 6-10 K range), so that future missions may use mechanical cryocoolers instead of liquid helium for pre-cooling. The continuous nature of the device gives it a much higher cooling power per unit mass, allowing it to be much smaller and lighter than existing ADRs with comparable performance. Design details are discussed along with prototype test results.

  19. A multistage gene normalization system integrating multiple effective methods.

    PubMed

    Li, Lishuang; Liu, Shanshan; Li, Lihua; Fan, Wenting; Huang, Degen; Zhou, Huiwei

    2013-01-01

    Gene/protein recognition and normalization is an important preliminary step for many biological text mining tasks. In this paper, we present a multistage gene normalization system which consists of four major subtasks: pre-processing, dictionary matching, ambiguity resolution and filtering. For the first subtask, we apply the gene mention tagger developed in our earlier work, which achieves an F-score of 88.42% on the BioCreative II GM testing set. In the stage of dictionary matching, the exact matching and approximate matching between gene names and the EntrezGene lexicon have been combined. For the ambiguity resolution subtask, we propose a semantic similarity disambiguation method based on Munkres' Assignment Algorithm. At the last step, a filter based on Wikipedia has been built to remove the false positives. Experimental results show that the presented system can achieve an F-score of 90.1%, outperforming most of the state-of-the-art systems. PMID:24349160

  20. Isotropic graphite multistage depressed collectors - A progress report

    NASA Astrophysics Data System (ADS)

    Ramins, Peter; Ebihara, Ben T.

    1989-04-01

    A small isotropic-graphite-electrode multistage depressed collector (MDC) was designed, fabricated, and evaluated in conjunction with a 500-W CW 4.8-9.6-GHz TWT. The carbon electrode surfaces were used to improve the TWT overall efficiency by minimizing the secondary-electron emission losses in the MDC. The design and fabrication of the brazed graphite MDC assembly are described. The TWT and graphite-electrode MDC bakeout and processing (outgassing) characteristics were evaluated and found to be comparable to those for TWTs equipped with copper-electrode MDCs. The TWT and MDC performance was optimized for broadband CW operation at saturation. The average RF, overall, and MDC efficiencies were 14.9, 46.4, and 83.6 percent, respectively, across the octave operating band. A 1500-h CW test showed no gas buildup and excellent stability of the electrode surfaces.

  1. Subsychronous vibration of multistage centrifugal compressors forced by rotating stall

    NASA Technical Reports Server (NTRS)

    Fulton, J. W.

    1987-01-01

    A multistage centrifugal compressor, in natural gas re-injection service on an offshore petroleum production platform, experienced subsynchronous vibrations which caused excessive bearing wear. Field performance testing correlated the subsynchronous amplitude with the discharge flow coefficient, demonstrating the excitation to be aerodynamic. Adding two impellers allowed an increase in the diffuser flow angle (with respect to tangential) to meet the diffuser stability criteria based on factory and field tests correlated using the theory of Senoo (for rotating stall in a vaneless diffuser). This modification eliminated all significant subsynchronous vibrations in field service, thus confirming the correctness of the solution. Other possible sources of aerodynamically induced vibrations were considered, but the judgment that those are unlikely has been confirmed by subsequent experience with other similar compressors.

  2. Clustering Acoustic Segments Using Multi-Stage Agglomerative Hierarchical Clustering

    PubMed Central

    2015-01-01

    Agglomerative hierarchical clustering becomes infeasible when applied to large datasets due to its O(N2) storage requirements. We present a multi-stage agglomerative hierarchical clustering (MAHC) approach aimed at large datasets of speech segments. The algorithm is based on an iterative divide-and-conquer strategy. The data is first split into independent subsets, each of which is clustered separately. Thus reduces the storage required for sequential implementations, and allows concurrent computation on parallel computing hardware. The resultant clusters are merged and subsequently re-divided into subsets, which are passed to the following iteration. We show that MAHC can match and even surpass the performance of the exact implementation when applied to datasets of speech segments. PMID:26517376

  3. 'Bootstrap' Configuration for Multistage Pulse-Tube Coolers

    NASA Technical Reports Server (NTRS)

    Nguyen, Bich; Nguyen, Lauren

    2008-01-01

    A bootstrap configuration has been proposed for multistage pulse-tube coolers that, for instance, provide final-stage cooling to temperatures as low as 20 K. The bootstrap configuration supplants the conventional configuration, in which customarily the warm heat exchangers of all stages reject heat at ambient temperature. In the bootstrap configuration, the warm heat exchanger, the inertance tube, and the reservoir of each stage would be thermally anchored to the cold heat exchanger of the next warmer stage. The bootstrapped configuration is superior to the conventional setup, in some cases increasing the 20 K cooler's coefficient of performance two-fold over that of an otherwise equivalent conventional layout. The increased efficiency could translate into less power consumption, less cooler mass, and/or lower cost for a given amount of cooling.

  4. The design and development of transonic multistage compressors

    NASA Technical Reports Server (NTRS)

    Ball, C. L.; Steinke, R. J.; Newman, F. A.

    1988-01-01

    The development of the transonic multistage compressor is reviewed. Changing trends in design and performance parameters are noted. These changes are related to advances in compressor aerodynamics, computational fluid mechanics and other enabling technologies. The parameters normally given to the designer and those that need to be established during the design process are identified. Criteria and procedures used in the selection of these parameters are presented. The selection of tip speed, aerodynamic loading, flowpath geometry, incidence and deviation angles, blade/vane geometry, blade/vane solidity, stage reaction, aerodynamic blockage, inlet flow per unit annulus area, stage/overall velocity ratio, and aerodynamic losses are considered. Trends in these parameters both spanwise and axially through the machine are highlighted. The effects of flow mixing and methods for accounting for the mixing in the design process are discussed.

  5. Multi-stage fuel cell system method and apparatus

    DOEpatents

    George, Thomas J.; Smith, William C.

    2000-01-01

    A high efficiency, multi-stage fuel cell system method and apparatus is provided. The fuel cell system is comprised of multiple fuel cell stages, whereby the temperatures of the fuel and oxidant gas streams and the percentage of fuel consumed in each stage are controlled to optimize fuel cell system efficiency. The stages are connected in a serial, flow-through arrangement such that the oxidant gas and fuel gas flowing through an upstream stage is conducted directly into the next adjacent downstream stage. The fuel cell stages are further arranged such that unspent fuel and oxidant laden gases too hot to continue within an upstream stage because of material constraints are conducted into a subsequent downstream stage which comprises a similar cell configuration, however, which is constructed from materials having a higher heat tolerance and designed to meet higher thermal demands. In addition, fuel is underutilized in each stage, resulting in a higher overall fuel cell system efficiency.

  6. A Multistage Gene Normalization System Integrating Multiple Effective Methods

    PubMed Central

    Li, Lishuang; Liu, Shanshan; Li, Lihua; Fan, Wenting; Huang, Degen; Zhou, Huiwei

    2013-01-01

    Gene/protein recognition and normalization is an important preliminary step for many biological text mining tasks. In this paper, we present a multistage gene normalization system which consists of four major subtasks: pre-processing, dictionary matching, ambiguity resolution and filtering. For the first subtask, we apply the gene mention tagger developed in our earlier work, which achieves an F-score of 88.42% on the BioCreative II GM testing set. In the stage of dictionary matching, the exact matching and approximate matching between gene names and the EntrezGene lexicon have been combined. For the ambiguity resolution subtask, we propose a semantic similarity disambiguation method based on Munkres' Assignment Algorithm. At the last step, a filter based on Wikipedia has been built to remove the false positives. Experimental results show that the presented system can achieve an F-score of 90.1%, outperforming most of the state-of-the-art systems. PMID:24349160

  7. Local network assessment

    NASA Astrophysics Data System (ADS)

    Glen, D. V.

    1985-04-01

    Local networks, related standards activities of the Institute of Electrical and Electronics Engineers the American National Standards Institute and other elements are presented. These elements include: (1) technology choices such as topology, transmission media, and access protocols; (2) descriptions of standards for the 802 local area networks (LAN's); high speed local networks (HSLN's) and military specification local networks; and (3) intra- and internetworking using bridges and gateways with protocols Interconnection (OSI) reference model. The convergence of LAN/PBX technology is also described.

  8. Communication Requirements and Interconnect Optimization forHigh-End Scientific Applications

    SciTech Connect

    Kamil, Shoaib; Oliker, Leonid; Pinar, Ali; Shalf, John

    2007-11-12

    The path towards realizing peta-scale computing isincreasingly dependent on building supercomputers with unprecedentednumbers of processors. To prevent the interconnect from dominating theoverall cost of these ultra-scale systems, there is a critical need forhigh-performance network solutions whose costs scale linearly with systemsize. This work makes several unique contributions towards attaining thatgoal. First, we conduct one of the broadest studies to date of high-endapplication communication requirements, whose computational methodsinclude: finite-difference, lattice-bolzmann, particle in cell, sparselinear algebra, particle mesh ewald, and FFT-based solvers. Toefficiently collect this data, we use the IPM (Integrated PerformanceMonitoring) profiling layer to gather detailed messaging statistics withminimal impact to code performance. Using the derived communicationcharacterizations, we next present fit-trees interconnects, a novelapproach for designing network infrastructure at a fraction of thecomponent cost of traditional fat-tree solutions. Finally, we propose theHybrid Flexibly Assignable Switch Topology (HFAST) infrastructure, whichuses both passive (circuit) and active (packet) commodity switchcomponents to dynamically reconfigure interconnects to suit thetopological requirements of scientific applications. Overall ourexploration leads to a promising directions for practically addressingthe interconnect requirements of future peta-scale systems.

  9. National Offshore Wind Energy Grid Interconnection Study Full Report

    SciTech Connect

    Daniel, John P.; Liu, Shu; Ibanez, Eduardo; Pennock, Ken; Reed, Gregory; Hanes, Spencer

    2014-07-30

    The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States.

  10. High temperature solid electrolyte fuel cell configurations and interconnections

    DOEpatents

    Isenberg, Arnold O.

    1984-01-01

    High temperature fuel cell configurations and interconnections are made including annular cells having a solid electrolyte sandwiched between thin film electrodes. The cells are electrically interconnected along an elongated axial outer surface.

  11. National Offshore Wind Energy Grid Interconnection Study Executive Summary

    SciTech Connect

    Daniel, John P.; Liu, Shu; Ibanez, Eduardo; Pennock, Ken; Reed, Gregory; Hanes, Spencer

    2014-07-30

    The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States.

  12. Aerodynamic Design Study of Advanced Multistage Axial Compressor

    NASA Technical Reports Server (NTRS)

    Larosiliere, Louis M.; Wood, Jerry R.; Hathaway, Michael D.; Medd, Adam J.; Dang, Thong Q.

    2002-01-01

    As a direct response to the need for further performance gains from current multistage axial compressors, an investigation of advanced aerodynamic design concepts that will lead to compact, high-efficiency, and wide-operability configurations is being pursued. Part I of this report describes the projected level of technical advancement relative to the state of the art and quantifies it in terms of basic aerodynamic technology elements of current design systems. A rational enhancement of these elements is shown to lead to a substantial expansion of the design and operability space. Aerodynamic design considerations for a four-stage core compressor intended to serve as a vehicle to develop, integrate, and demonstrate aerotechnology advancements are discussed. This design is biased toward high efficiency at high loading. Three-dimensional blading and spanwise tailoring of vector diagrams guided by computational fluid dynamics (CFD) are used to manage the aerodynamics of the high-loaded endwall regions. Certain deleterious flow features, such as leakage-vortex-dominated endwall flow and strong shock-boundary-layer interactions, were identified and targeted for improvement. However, the preliminary results were encouraging and the front two stages were extracted for further aerodynamic trimming using a three-dimensional inverse design method described in part II of this report. The benefits of the inverse design method are illustrated by developing an appropriate pressure-loading strategy for transonic blading and applying it to reblade the rotors in the front two stages of the four-stage configuration. Multistage CFD simulations based on the average passage formulation indicated an overall efficiency potential far exceeding current practice for the front two stages. Results of the CFD simulation at the aerodynamic design point are interrogated to identify areas requiring additional development. In spite of the significantly higher aerodynamic loadings, advanced CFD

  13. Feet swelling in a multistage ultraendurance triathlete: a case study.

    PubMed

    Knechtle, Beat; Zingg, Matthias Alexander; Knechtle, Patrizia; Rosemann, Thomas; Rüst, Christoph Alexander

    2015-01-01

    Recent studies investigating ultraendurance athletes showed an association between excessive fluid intake and swelling of the lower limbs such as the feet. To date, this association has been investigated in single-stage ultraendurance races, but not in multistage ultraendurance races. In this case study, we investigated a potential association between fluid intake and feet swelling in a multistage ultraendurance race such as a Deca Iron ultratriathlon with ten Ironman triathlons within 10 consecutive days. A 49-year-old well-experienced ultratriathlete competed in autumn 2013 in the Deca Iron ultratriathlon held in Lonata del Garda, Italy, and finished the race as winner within 129:33 hours:minutes. Changes in body mass (including body fat and lean body mass), foot volume, total body water, and laboratory measurements were assessed. Food and fluid intake during rest and competing were recorded, and energy and fluid turnovers were estimated. During the ten stages, the volume of the feet increased, percentage body fat decreased, creatinine and urea levels increased, hematocrit and hemoglobin values decreased, and plasma [Na(+)] remained unchanged. The increase in foot volume was significantly and positively related to fluid intake during the stages. The poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. This case report shows that the volume of the foot increased during the ten stages, and the increase in volume was significantly and positively related to fluid intake during the stages. Furthermore, the poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. The continuous feet swelling during the race was most probably due to a combination of a high fluid intake and a progressive decline in renal function (ie, continuous increase in creatinine and urea), leading to body fluid retention (ie, increase in total body water). PMID:26508884

  14. Advanced multistage turbine blade aerodynamics, performance, cooling, and heat transfer

    SciTech Connect

    Fleeter, S.; Lawless, P.B.

    1995-10-01

    The gas turbine has the potential for power production at the highest possible efficiency. The challenge is to ensure that gas turbines operate at the optimum efficiency so as to use the least fuel and produce minimum emissions. A key component to meeting this challenge is the turbine. Turbine performance, both aerodynamics and heat transfer, is one of the barrier advanced gas turbine development technologies. This is a result of the complex, highly three-dimensional and unsteady flow phenomena in the turbine. Improved turbine aerodynamic performance has been achieved with three-dimensional highly-loaded airfoil designs, accomplished utilizing Euler or Navier-Stokes Computational Fluid Dynamics (CFD) codes. These design codes consider steady flow through isolated blade rows. Thus they do not account for unsteady flow effects. However, unsteady flow effects have a significant impact on performance. Also, CFD codes predict the complete flow field. The experimental verification of these codes has traditionally been accomplished with point data - not corresponding plane field measurements. Thus, although advanced CFD predictions of the highly complex and three-dimensional turbine flow fields are available, corresponding data are not. To improve the design capability for high temperature turbines, a detailed understanding of the highly unsteady and three-dimensional flow through multi-stage turbines is necessary. Thus, unique data are required which quantify the unsteady three-dimensional flow through multi-stage turbine blade rows, including the effect of the film coolant flow. This requires experiments in appropriate research facilities in which complete flow field data, not only point measurements, are obtained and analyzed. Also, as design CFD codes do not account for unsteady flow effects, the next logical challenge and the current thrust in CFD code development is multiple-stage analyses that account for the interactions between neighboring blade rows.

  15. Feet swelling in a multistage ultraendurance triathlete: a case study

    PubMed Central

    Knechtle, Beat; Zingg, Matthias Alexander; Knechtle, Patrizia; Rosemann, Thomas; Rüst, Christoph Alexander

    2015-01-01

    Recent studies investigating ultraendurance athletes showed an association between excessive fluid intake and swelling of the lower limbs such as the feet. To date, this association has been investigated in single-stage ultraendurance races, but not in multistage ultraendurance races. In this case study, we investigated a potential association between fluid intake and feet swelling in a multistage ultraendurance race such as a Deca Iron ultratriathlon with ten Ironman triathlons within 10 consecutive days. A 49-year-old well-experienced ultratriathlete competed in autumn 2013 in the Deca Iron ultratriathlon held in Lonata del Garda, Italy, and finished the race as winner within 129:33 hours:minutes. Changes in body mass (including body fat and lean body mass), foot volume, total body water, and laboratory measurements were assessed. Food and fluid intake during rest and competing were recorded, and energy and fluid turnovers were estimated. During the ten stages, the volume of the feet increased, percentage body fat decreased, creatinine and urea levels increased, hematocrit and hemoglobin values decreased, and plasma [Na+] remained unchanged. The increase in foot volume was significantly and positively related to fluid intake during the stages. The poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. This case report shows that the volume of the foot increased during the ten stages, and the increase in volume was significantly and positively related to fluid intake during the stages. Furthermore, the poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. The continuous feet swelling during the race was most probably due to a combination of a high fluid intake and a progressive decline in renal function (ie, continuous increase in creatinine and urea), leading to body fluid retention (ie, increase in total body water). PMID:26508884

  16. Weaves as an Interconnection Fabric for ASIM's and Nanosatellites

    NASA Technical Reports Server (NTRS)

    Gorlick, Michael M.

    1995-01-01

    Many of the micromachines under consideration require computer support, indeed, one of the appeals of this technology is the ability to intermix mechanical, optical, analog, and digital devices on the same substrate. The amount of computer power is rarely an issue, the sticking point is the complexity of the software required to make effective use of these devices. Micromachines are the nano-technologist's equivalent of 'golden screws'. In other words, they will be piece parts in larger assemblages. For example, a nano-satellite may be composed of stacked silicon wafers where each wafer contains hundreds to thousands of micromachines, digital controllers, general purpose computers, memories, and high-speed bus interconnects. Comparatively few of these devices will be custom designed, most will be stock parts selected from libraries and catalogs. The novelty will lie in the interconnections. For example, a digital accelerometer may be a component part in an adaptive suspension, a monitoring element embedded in the wrapper of a package, or a portion of the smart skin of a launch vehicle. In each case, this device must inter-operate with other devices and probes for the purposes of command, control, and communication. We propose a software technology called 'weaves' that will permit large collections of micromachines and their attendant computers to freely intercommunicate while preserving modularity, transparency, and flexibility. Weaves are composed of networks of communicating software components. The network, and the components comprising it, may be changed even while the software, and the devices it controls, are executing. This unusual degree of software plasticity permits micromachines to dynamically adapt the software to changing conditions and allows system engineers to rapidly and inexpensively develop special purpose software by assembling stock software components in custom configurations.

  17. Integrated silicon photonic interconnect with surface-normal optical interface

    NASA Astrophysics Data System (ADS)

    Zhang, Zanyun; Huang, Beiju; Zhang, Zan; Cheng, Chuantong; Liu, Hongwei; Li, Hongqiang; Chen, Hongda

    2016-05-01

    An integrated silicon photonic interconnect with surface-normal optical interface is demonstrated by connecting a bidirectional grating based E-O modulator and a germanium waveguide photodetector. To investigate this photonic interconnect, both static and dynamic performance of the discrete devices are characterized respectively. Based on the characterization work, data transmission experiment is carried out for the photonic interconnect. Eye diagram results indicate the photonic interconnect can operate up to 7 Gb/s.

  18. Hot Chips and Hot Interconnects for High End Computing Systems

    NASA Technical Reports Server (NTRS)

    Saini, Subhash

    2005-01-01

    I will discuss several processors: 1. The Cray proprietary processor used in the Cray X1; 2. The IBM Power 3 and Power 4 used in an IBM SP 3 and IBM SP 4 systems; 3. The Intel Itanium and Xeon, used in the SGI Altix systems and clusters respectively; 4. IBM System-on-a-Chip used in IBM BlueGene/L; 5. HP Alpha EV68 processor used in DOE ASCI Q cluster; 6. SPARC64 V processor, which is used in the Fujitsu PRIMEPOWER HPC2500; 7. An NEC proprietary processor, which is used in NEC SX-6/7; 8. Power 4+ processor, which is used in Hitachi SR11000; 9. NEC proprietary processor, which is used in Earth Simulator. The IBM POWER5 and Red Storm Computing Systems will also be discussed. The architectures of these processors will first be presented, followed by interconnection networks and a description of high-end computer systems based on these processors and networks. The performance of various hardware/programming model combinations will then be compared, based on latest NAS Parallel Benchmark results (MPI, OpenMP/HPF and hybrid (MPI + OpenMP). The tutorial will conclude with a discussion of general trends in the field of high performance computing, (quantum computing, DNA computing, cellular engineering, and neural networks).

  19. Are there any factors influencing the course of multistage treatment in Hirschsprung's disease?

    PubMed Central

    Błaszczyński, Michał; Moryciński, Sebastian; Porzucek, Witold; Mańkowski, Przemysław

    2016-01-01

    Introduction Surgical treatment of Hirschsprung's disease may be performed in a single step, or in stages with a temporary stoma. The therapy depends on the clinical condition of the patient and the severity of symptoms. Planned multistage treatment is carried out in two or three steps. Aim To analyse our 15 years of experience with multistage surgery for the treatment of Hirschsprung's disease, to identify multistage-related factors influencing the course of surgery and hospitalisation, and to evaluate the probability of complications during multistage treatment. Material and methods The study material was collected on the basis of documentation of patients treated during the years 2000 to 2014. The parameters concerning surgery and hospitalisation were statistically analysed. Results Twenty nine patients were treated with multistage surgery using the following methods: Duhamel-Martin and Transanal Endorectal Pull-Through (TEPT). There were significant correlations (p < 0.05) between length of resected intestine and operative time. Classification and Regression Tree (CRT) was used to classify the operated children depending on the presentence of complications after surgery. Conclusions The incidence of complications during multistage treatment for both methods was comparable. It is difficult to objectively compare the Duhamel-Martin and TEPT techniques because of the different indicators for their use in multistage surgery. Intestinal adhesions were the most common complication after definitive surgery. Younger age of the operated patients was associated with greater risk of adhesion formation. PMID:27350842

  20. 14 CFR 29.957 - Flow between interconnected tanks.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flow between interconnected tanks. 29.957... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.957 Flow between interconnected tanks. (a) Where tank outlets are interconnected and allow fuel to flow...

  1. 14 CFR 23.957 - Flow between interconnected tanks.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flow between interconnected tanks. 23.957... Fuel System § 23.957 Flow between interconnected tanks. (a) It must be impossible, in a gravity feed system with interconnected tank outlets, for enough fuel to flow between the tanks to cause an...

  2. Development of Interconnect Technologies for Particle Detectors

    SciTech Connect

    Tripathi, Mani

    2015-01-29

    This final report covers the three years of this grant, for the funding period 9/1/2010 - 8/31/2013. The project consisted of generic detector R&D work at UC Davis, with an emphasis on developing interconnect technologies for applications in HEP. Much of the work is done at our Facility for Interconnect Technologies (FIT) at UC Davis. FIT was established using ARRA funds, with further studies supported by this grant. Besides generic R&D work at UC Davis, FIT is engaged in providing bump bonding help to several DOE supported detector R&D efforts. Some of the developmental work was also supported by funding from other sources: continuing CMS project funds and the Linear Collider R&D funds. The latter program is now terminated. The three year program saw a good deal of progress on several fronts, which are reported here.

  3. Release Resistant Electrical Interconnections For Mems Devices

    DOEpatents

    Peterson, Kenneth A.; Garrett, Stephen E.; Reber, Cathleen A.

    2005-02-22

    A release resistant electrical interconnection comprising a gold-based electrical conductor compression bonded directly to a highly-doped polysilicon bonding pad in a MEMS, IMEMS, or MOEMS device, without using any intermediate layers of aluminum, titanium, solder, or conductive adhesive disposed in-between the conductor and polysilicon pad. After the initial compression bond has been formed, subsequent heat treatment of the joint above 363 C creates a liquid eutectic phase at the bondline comprising gold plus approximately 3 wt % silicon, which, upon re-solidification, significantly improves the bond strength by reforming and enhancing the initial bond. This type of electrical interconnection is resistant to chemical attack from acids used for releasing MEMS elements (HF, HCL), thereby enabling the use of a "package-first, release-second" sequence for fabricating MEMS devices. Likewise, the bond strength of an Au--Ge compression bond may be increased by forming a transient liquid eutectic phase comprising Au-12 wt % Ge.

  4. Interconnection of bundled solid oxide fuel cells

    SciTech Connect

    Brown, Michael; Bessette, II, Norman F; Litka, Anthony F; Schmidt, Douglas S

    2014-01-14

    A system and method for electrically interconnecting a plurality of fuel cells to provide dense packing of the fuel cells. Each one of the plurality of fuel cells has a plurality of discrete electrical connection points along an outer surface. Electrical connections are made directly between the discrete electrical connection points of adjacent fuel cells so that the fuel cells can be packed more densely. Fuel cells have at least one outer electrode and at least one discrete interconnection to an inner electrode, wherein the outer electrode is one of a cathode and and anode and wherein the inner electrode is the other of the cathode and the anode. In tubular solid oxide fuel cells the discrete electrical connection points are spaced along the length of the fuel cell.

  5. Copper Nanowire Production for Interconnect Applications

    NASA Technical Reports Server (NTRS)

    Han, Jin-Woo (Inventor); Meyyappan, Meyya (Inventor)

    2014-01-01

    A method of fabricating metallic Cu nanowires with lengths up to about 25 micrometers and diameters in a range 20-100 nanometers, or greater if desired. Vertically oriented or laterally oriented copper oxide structures (CuO and/or Cu2O) are grown on a Cu substrate. The copper oxide structures are reduced with 99+ percent H or H2, and in this reduction process the lengths decrease (to no more than about 25 micrometers), the density of surviving nanostructures on a substrate decreases, and the diameters of the surviving nanostructures have a range, of about 20-100 nanometers. The resulting nanowires are substantially pure Cu and can be oriented laterally (for local or global interconnects) or can be oriented vertically (for standard vertical interconnects).

  6. A covariance analysis algorithm for interconnected systems

    NASA Technical Reports Server (NTRS)

    Cheng, Victor H. L.; Curley, Robert D.; Lin, Ching-An

    1987-01-01

    A covariance analysis algorithm for propagation of signal statistics in arbitrarily interconnected nonlinear systems is presented which is applied to six-degree-of-freedom systems. The algorithm uses statistical linearization theory to linearize the nonlinear subsystems, and the resulting linearized subsystems are considered in the original interconnection framework for propagation of the signal statistics. Some nonlinearities commonly encountered in six-degree-of-freedom space-vehicle models are referred to in order to illustrate the limitations of this method, along with problems not encountered in standard deterministic simulation analysis. Moreover, the performance of the algorithm shall be numerically exhibited by comparing results using such techniques to Monte Carlo analysis results, both applied to a simple two-dimensional space-intercept problem.

  7. Viewing Integrated-Circuit Interconnections By SEM

    NASA Technical Reports Server (NTRS)

    Lawton, Russel A.; Gauldin, Robert E.; Ruiz, Ronald P.

    1990-01-01

    Back-scattering of energetic electrons reveals hidden metal layers. Experiment shows that with suitable operating adjustments, scanning electron microscopy (SEM) used to look for defects in aluminum interconnections in integrated circuits. Enables monitoring, in situ, of changes in defects caused by changes in temperature. Gives truer picture of defects, as etching can change stress field of metal-and-passivation pattern, causing changes in defects.

  8. A STUDY OF MULTISTAGE/MULTIFUNCTION COLUMN FOR FINE PARTICLE SEPARATION

    SciTech Connect

    Dr. Shiao-Hung Chiang

    1999-10-01

    A non-agitated multi-stage column was constructed and applied to wastewater treatment. Preliminary oil/water separation tests were performed. Excellent separation results verifies the multi-function feature of the multi-stage column. Hydrodynamic behavior is considered as the underlying cause for the separation performance. Therefore, a series of experiments were carried out to investigate the hydrodynamic parameters, including gas holdups and liquid circulating velocities. The experimental data will be used to create a mathematical model to simulate the multi-stage column process. The model will further shed light on the future scale-up of the MSTLFLO process.

  9. A Study of Multistage/Multifunction Column for Fine Particle Separation.

    SciTech Connect

    Chiang, S.

    1997-09-15

    A non-agitated multi-stage column was constructed and applied to wastewater treatment. Preliminary oil/water separation tests were performed. Excellent separation results verifies the multi-function feature of the multi-stage column. Hydrodynamic behavior is considered as the underlying cause for the separation performance. Therefore, a series of experiments were carried out to investigate the hydrodynamic parameters, including gas holdups and liquid circulating velocities. The experimental data will be used to create a mathematical model to simulate the multi-stage column process. The model will further shed light on the future scale-up of the MSTLFLO process.

  10. Optical interconnections on printed circuit boards

    NASA Astrophysics Data System (ADS)

    Griese, Elmar

    2000-05-01

    In this paper an optical interconnection technology for high-speed printed circuit board application is presented. This technology is widely compatible with the existing design and manufacturing technologies of conventional multi- layer pc boards and it combines electrical and optical interconnects on pc board level. Using this interconnection technology on-board bandwidth of several Gbps can be realized. As conventional pc board technology provides sufficient performance characteristics for the majority of all on-board signals only a hybrid technology which is compatible to the existing printed circuit board design and manufacturing processes is able to lead to a practical solution at reasonable cost. This compatibility demand results in different technological, functional, and economic requirements which also consider potential application for high performance computing and telecommunication hardware. In this paper an overview is given on the requirements, on the basic technologies for manufacturing electrical-optical pc boards as well as on the extended design process with its modeling and simulation methodologies and strategies.

  11. Dimensioning of nearby substations interconnected ground system

    SciTech Connect

    Sobral, S.T. ); Costa, V.S. ); Campos, M.S.; Goldman, B. ); Mukhedkar, D. )

    1988-10-01

    This paper deals with the ground mat dimensioning of two or more neighbor interconnected substations, a situation that is very common in the Electrical Industry. The paper recalls that the external ground circuits connected to the ground grid of each substation can drastically reduce the percentage of total ground current injected into the soil through the mat (from 40% up to 2% of the total fault current). The paper presents a set of specific calculation procedures to deal with nearby interconnected ground mats. These procedures correspond to a particular illustration of the general ''Decoupled Method'' (3,4,5), showing how to apply its 8 sequencial steps to solve this type of circuit. The paper shows that the electric neighborhood of nearby substations depends on the ''Space Constant'' (or ''Characteristic Length'') of the ground circuits interconnecting them such as transmission line ground-wires, power cable sheaths, etc. This paper complements also Ref. (3,4), introducing the complete derivation of useful expressions used to solve lumped parameter ladder circuits of any size (from one pi to an infinite number of pis). The derivation of these expressions also used in (3,4) were not included in these References due to lack of space. In the paper it is also shown a simple procedure to determine the suitable number of ACSR ground-wire spans near a substation necessary to allow a reduction of the ground grid conductor extension.

  12. Potential roles of optical interconnections within broadband switching modules

    NASA Astrophysics Data System (ADS)

    Lalk, Gail R.; Habiby, Sarry F.; Hartman, Davis H.; Krchnavek, Robert R.; Wilson, Donald K.; Young, Kenneth C., Jr.

    1991-04-01

    An investigation of potential physical design bottlenecks in future broadband telecommunication switches has led to the identification of several areas where optical interconnections may play a role in the practical realization of required system performance. In the model used the speed and interconnection densities as well as requirements for ease-of-access and efficient power utilization challenge conventional partitioning and packaging strategies. Potential areas where optical interconnections may relieve some of the physical design bottlenecks include fiber management at the customer interface to the switch routing and distribution of high-density interconnections within the fabric of the switch and backplane interconnections to increase system throughput.

  13. Polymer optical interconnect technology (POINT): optoelectronic packaging and interconnect for board and backplane applications

    NASA Astrophysics Data System (ADS)

    Liu, Yung S.; Wojnarowski, R. J.; Hennessy, W. A.; Bristow, Julian P.; Liu, Yue; Peczalski, Andrzej; Rowlette, John R.; Plotts, Alan; Stack, Jared D.; Yardley, James T.; Eldada, L.; Osgood, Richard M.; Scarmozzino, Robert; Lee, Sing H.; Ozguz, Volkan H.

    1996-01-01

    The polymer optical interconnect technology (POINT) represents a major collaborative effort among GE, Honeywell, AMP, AlliedSignal, Columbia University and the University of California at San Diego (UCSD), sponsored by ARPA, in developing affordable optoelectronic module packaging and interconnect technologies for board- and backplane-level optical interconnect applications for a wide range of military and commercial applications. The POINT program takes a novel development approach by fully leveraging the existing electronic design, processing, fabrication, and module packaging technologies to optoelectronic module packaging. The POINT program further incorporates several state-of- the-art optoelectronic technologies that include high-speed VCSEL for multichannel array data transmission; flexible optical polymers such as PolyguideTM or coupling of device-to- fiber using a passive alignment process; a low-loss polymer for backplane interconnect to provide a high I/O density; low-cost diffractive optical elements (DOE) for board-to-backplane interconnect; and use of molded MT array ferrule to reduce overall system size, weight, and cost. In addition to further reducing design and fabrication cycle times, computer simulation tools for optical waveguide and mechanical modeling will be advanced under the POINT program.

  14. Mach-Zehnder-based five-port silicon router for optical interconnects.

    PubMed

    Li, Xianyao; Xiao, Xi; Xu, Hao; Li, Zhiyong; Chu, Tao; Yu, Jinzhong; Yu, Yude

    2013-05-15

    We propose and fabricate a five-port silicon optical router based on Mach-Zehnder interferometer switches. Only 10 switching elements and five low-loss waveguide crossings are required in our design. Through thermal control of the switching network, we successfully demonstrate 20 possible I/O paths of the five-port optical router at a data transmission rate of 32 Gb/s. The results here show great potential for application in ultrahigh-capacity optical interconnects. PMID:23938917

  15. AERODYNAMIC AND BLADING DESIGN OF MULTISTAGE AXIAL FLOW COMPRESSORS

    NASA Technical Reports Server (NTRS)

    Crouse, J. E.

    1994-01-01

    The axial-flow compressor is used for aircraft engines because it has distinct configuration and performance advantages over other compressor types. However, good potential performance is not easily obtained. The designer must be able to model the actual flows well enough to adequately predict aerodynamic performance. This computer program has been developed for computing the aerodynamic design of a multistage axial-flow compressor and, if desired, the associated blading geometry input for internal flow analysis. The aerodynamic solution gives velocity diagrams on selected streamlines of revolution at the blade row edges. The program yields aerodynamic and blading design results that can be directly used by flow and mechanical analysis codes. Two such codes are TSONIC, a blade-to-blade channel flow analysis code (COSMIC program LEW-10977), and MERIDL, a more detailed hub-to-shroud flow analysis code (COSMIC program LEW-12966). The aerodynamic and blading design program can reduce the time and effort required to obtain acceptable multistage axial-flow compressor configurations by generating good initial solutions and by being compatible with available analysis codes. The aerodynamic solution assumes steady, axisymmetric flow so that the problem is reduced to solving the two-dimensional flow field in the meridional plane. The streamline curvature method is used for the iterative aerodynamic solution at stations outside of the blade rows. If a blade design is desired, the blade elements are defined and stacked within the aerodynamic solution iteration. The blade element inlet and outlet angles are established by empirical incidence and deviation angles to the relative flow angles of the velocity diagrams. The blade element centerline is composed of two segments tangentially joined at a transition point. The local blade angle variation of each element can be specified as a fourth-degree polynomial function of path distance. Blade element thickness can also be specified

  16. Unsteady Flow Field in a Multistage Axial Flow Compressor

    NASA Technical Reports Server (NTRS)

    Suryavamshi, N.; Lakshminarayana, B.; Prato, J.

    1997-01-01

    The flow field in a multistage compressor is three-dimensional, unsteady, and turbulent with substantial viscous effects. Some of the specific phenomena that has eluded designers include the effects of rotor-stator and rotor-rotor interactions and the physics of mixing of velocity, pressure, temperature and velocity fields. An attempt was made, to resolve experimentally, the unsteady pressure and temperature fields downstream of the second stator of a multistage axial flow compressor which will provide information on rotor-stator interaction effects and the nature of the unsteadiness in an embedded stator of a three stage axial flow compressor. Detailed area traverse measurements using pneumatic five hole probe, thermocouple probe, semi-conductor total pressure probe (Kulite) and an aspirating probe downstream of the second stator were conducted at the peak efficiency operating condition. The unsteady data was then reduced through an ensemble averaging technique which splits the signal into deterministic and unresolved components. Auto and cross correlation techniques were used to correlate the deterministic total temperature and velocity components (acquired using a slanted hot-film probe at the same measurement locations) and the gradients, distributions and relative weights of each of the terms of the average passage equation were then determined. Based on these measurements it was observed that the stator wakes, hub leakage flow region, casing endwall suction surface corner region, and the casing endwall region away from the blade surfaces were the regions of highest losses in total pressure, lowest efficiency and highest levels of unresolved unsteadiness. The deterministic unsteadiness was found to be high in the hub and casing endwall regions as well as on the pressure side of the stator wake. The spectral distribution of hot-wire and kulite voltages shows that at least eight harmonics of all three rotor blade passing frequencies are present at this

  17. Particle swarm optimization of ascent trajectories of multistage launch vehicles

    NASA Astrophysics Data System (ADS)

    Pontani, Mauro

    2014-02-01

    Multistage launch vehicles are commonly employed to place spacecraft and satellites in their operational orbits. If the rocket characteristics are specified, the optimization of its ascending trajectory consists of determining the optimal control law that leads to maximizing the final mass at orbit injection. The numerical solution of a similar problem is not trivial and has been pursued with different methods, for decades. This paper is concerned with an original approach based on the joint use of swarming theory and the necessary conditions for optimality. The particle swarm optimization technique represents a heuristic population-based optimization method inspired by the natural motion of bird flocks. Each individual (or particle) that composes the swarm corresponds to a solution of the problem and is associated with a position and a velocity vector. The formula for velocity updating is the core of the method and is composed of three terms with stochastic weights. As a result, the population migrates toward different regions of the search space taking advantage of the mechanism of information sharing that affects the overall swarm dynamics. At the end of the process the best particle is selected and corresponds to the optimal solution to the problem of interest. In this work the three-dimensional trajectory of the multistage rocket is assumed to be composed of four arcs: (i) first stage propulsion, (ii) second stage propulsion, (iii) coast arc (after release of the second stage), and (iv) third stage propulsion. The Euler-Lagrange equations and the Pontryagin minimum principle, in conjunction with the Weierstrass-Erdmann corner conditions, are employed to express the thrust angles as functions of the adjoint variables conjugate to the dynamics equations. The use of these analytical conditions coming from the calculus of variations leads to obtaining the overall rocket dynamics as a function of seven parameters only, namely the unknown values of the initial state

  18. A multi-stage methodology for selecting input variables in ANN forecasting flows

    NASA Astrophysics Data System (ADS)

    Panagoulia, Dionysia; Tsekouras, George; Kousiouris, George

    2016-04-01

    Recently, several methods have more or less efficiently dealt with the selection of input variables to artificial neural networks (ANNs) in the hydrology and water resources domain. While the ultimate purpose is to approximate an effective and computationally parsimonious method accounting for non linear input variables to ANNs, very few approaches could reach this target. Moreover, none of these has considered the seasonality as input to ANNs which may be attributed to the influence of natural or anthropogenic variability to hydro-meteorological time series. To this end, a novel methodology is developed for selecting input variables used in artificial neural network (ANNs) models for flow forecasting. The proposed methodology is generic, multi-stage and makes use of data correlations together with a set of crucial statistical indices for optimizing model performance, both in terms of ANN structure (e.g. neurons, momentum rate, learning rate, activation functions) but also in terms of inputs selection. Daily areal precipitation and temperature data coupled with atmospheric circulation in the form of circulation patterns, observed river flow data, and time expressed via functions of sine and cosine (seasonality) were the potential vectors for inputs selection. The historical data concern the mountainous Mesochora catchment in Central-Western Greece. The proposed methodology revealed the river flow of past four days, the precipitation of past three days and the seasonality as robust input variables. However, the temperature of three past days should be considered as an alternative against the seasonality. The produced models forecasting ability was validated by comparing its one-step ahead flow prediction ability to two other approaches (an auto regressive model and a GA-optimized single input ANN).

  19. Design of a multistage depressed collector for the F-16 radar dual mode transmitter tube

    NASA Technical Reports Server (NTRS)

    Dayton, J. A., Jr.

    1982-01-01

    The design of a multistage depressed collector (MDC) for use with the F-16 radar dual mode transmitter tube is described. The methods employed and the rationale on which the design is based are presented.

  20. EPA'S LIMB (ENVIRONMENTAL PROTECTION AGENCY'S LIMESTONE INJECTION MULTISTAGE BURNER) RESEARCH, DEVELOPMENT, AND DEMONSTRATION PROGRAM

    EPA Science Inventory

    The paper describes and discusses key design features of the retrofit of EPA's Limestone Injection Multistage Burner (LIMB) system to an operating, wallfired utility boiler at Ohio Edison's Edgewater Station, based on the preliminary engineering design. It further describes resul...

  1. Mutually connected component of networks of networks with replica nodes

    NASA Astrophysics Data System (ADS)

    Bianconi, Ginestra; Dorogovtsev, Sergey N.; Mendes, José F. F.

    2015-01-01

    We describe the emergence of the giant mutually connected component in networks of networks in which each node has a single replica node in any layer and can be interdependent only on its replica nodes in the interdependent layers. We prove that if, in these networks, all the nodes of one network (layer) are interdependent on the nodes of the same other interconnected layer, then, remarkably, the mutually connected component does not depend on the topology of the network of networks. This component coincides with the mutual component of the fully connected network of networks constructed from the same set of layers, i.e., a multiplex network.

  2. Microfluidic assembly of multistage porous silicon–lipid vesicles for controlled drug release

    PubMed Central

    Herranz-Blanco, Bárbara; Arriaga, Laura R.; Mäkilä, Ermei; Correia, Alexandra; Shrestha, Neha; Mirza, Sabiruddin; Weitz, David A.; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A.

    2014-01-01

    A reliable microfluidic platform for the generation of stable and monodisperse multistage drug delivery systems is reported. A glass-capillary flow-focusing droplet generation device was used to encapsulate thermally hydrocarbonized porous silicon (PSi) microparticles into the aqueous cores of double emulsion drops, yielding the formation of a multistage PSi-lipid vesicle. This composite system enables a large loading capacity for hydrophobic drugs. PMID:24469311

  3. Extensive site-directed mutagenesis reveals interconnected functional units in the alkaline phosphatase active site.

    PubMed

    Sunden, Fanny; Peck, Ariana; Salzman, Julia; Ressl, Susanne; Herschlag, Daniel

    2015-01-01

    Enzymes enable life by accelerating reaction rates to biological timescales. Conventional studies have focused on identifying the residues that have a direct involvement in an enzymatic reaction, but these so-called 'catalytic residues' are embedded in extensive interaction networks. Although fundamental to our understanding of enzyme function, evolution, and engineering, the properties of these networks have yet to be quantitatively and systematically explored. We dissected an interaction network of five residues in the active site of Escherichia coli alkaline phosphatase. Analysis of the complex catalytic interdependence of specific residues identified three energetically independent but structurally interconnected functional units with distinct modes of cooperativity. From an evolutionary perspective, this network is orders of magnitude more probable to arise than a fully cooperative network. From a functional perspective, new catalytic insights emerge. Further, such comprehensive energetic characterization will be necessary to benchmark the algorithms required to rationally engineer highly efficient enzymes. PMID:25902402

  4. Smart-pixel-based free-space interconnects: solving the high-speed multichip packaging bottleneck

    NASA Astrophysics Data System (ADS)

    Haney, Michael W.; Christensen, Marc P.; Milojkovic, Predrag; McFadden, Michael J.

    2001-11-01

    As IC densities grow to 100's of millions of devices per chip and beyond, the inter-chip link bandwidth becomes a critical performance-limiting bottleneck in many applications. Electronic packaging technology has not kept pace with the growth of IC I/O requirements. Recent advances in smart pixel technology, however, offer the potential to use 3-D optical interconnects to overcome the inter-chip I/O bottleneck by linking dense arrays of Vertical Cavity Surface Emitting Lasers (VCSELs) and photodetectors, which are directly integrated onto electronic IC circuits. Many switching and parallel computing applications demand multi-chip interconnection fabrics that achieve high-density global I/O across an array of chips. Such global interconnections require a high degree of space-variance in the interconnection fabric, in addition to high inter-chip throughput capacity. This paper reviews the architectural and optical design issues associated with global interconnections among arrays of chips. The emphasis is on progress made in the design and implementation of the second generation Free-space Accelerator for Switching Terabit Networks (FAST-Net) prototype. The FAST-Net prototype uses a macro-optical lens array and mirror to effect a global (fully connected) fabric across a 4 X 4 array of smart pixel chips. Clusters of VCSELs and photodetectors are imaged onto corresponding clusters on other chips, creating a high- density bi-directional data path between every pair of smart pixel chips on a multi-chip module. The combination of programmable intra-chip electronic routing and the fixed global inter-chip optical interconnection pattern of the FAST- Net architecture has been shown to provide a low latency, minimum complexity fabric, that can effect an arbitrary interconnection pattern across the chip array. Recent experimental results show that the narrow beam characteristics of VCSELs can be exploited in an efficient optical design for the FAST-Net optical interconnection

  5. Silicon integrated nanophotonics for on-chip interconnects

    NASA Astrophysics Data System (ADS)

    Vlasov, Yurii

    2008-03-01

    Current trend in microelectronics industry is to increase the parallelism in computation by multi-threading, by building large scale multi-chip systems and, more recently, by increasing the number of cores on a single chip. With such increase of parallelization the interconnect bandwidth between the racks, chips or different cores is becoming a limiting factor for the design of high performance computer systems. The on-chip ultrahigh-bandwidth silicon-based photonic network might provide an attractive solution to this bandwidth bottleneck. We will review recent results on silicon nanophotonic circuits based on photonic wires and photonic crystals. Strong light confinement at the diffraction limit enables dramatic scaling of the device area and allows unprecedented control over optical signals. Silicon nanophotonic devices have immense capacity for low-loss, high-bandwidth data processing that might enable the design of ultra-compact on-chip optical networks. In particular we will show recent results on design and characterization of various ultra-compact (<0.03mm2) silicon nanophotonic circuits as optical delay lines, electro-optic modulators, broadband optical switches, wavelength filters, etc.

  6. Printed polymer photonic devices for optical interconnect systems

    NASA Astrophysics Data System (ADS)

    Subbaraman, Harish; Pan, Zeyu; Zhang, Cheng; Li, Qiaochu; Guo, L. J.; Chen, Ray T.

    2016-03-01

    Polymer photonic device fabrication usually relies on the utilization of clean-room processes, including photolithography, e-beam lithography, reactive ion etching (RIE) and lift-off methods etc, which are expensive and are limited to areas as large as a wafer. Utilizing a novel and a scalable printing process involving ink-jet printing and imprinting, we have fabricated polymer based photonic interconnect components, such as electro-optic polymer based modulators and ring resonator switches, and thermo-optic polymer switch based delay networks and demonstrated their operation. Specifically, a modulator operating at 15MHz and a 2-bit delay network providing up to 35.4ps are presented. In this paper, we also discuss the manufacturing challenges that need to be overcome in order to make roll-to-roll manufacturing practically viable. We discuss a few manufacturing challenges, such as inspection and quality control, registration, and web control, that need to be overcome in order to realize true implementation of roll-to-roll manufacturing of flexible polymer photonic systems. We have overcome these challenges, and currently utilizing our inhouse developed hardware and software tools, <10μm alignment accuracy at a 5m/min is demonstrated. Such a scalable roll-to-roll manufacturing scheme will enable the development of unique optoelectronic devices which can be used in a myriad of different applications, including communication, sensing, medicine, security, imaging, energy, lighting etc.

  7. Tuning of the droplet motion in interconnected microfluidic devices

    NASA Astrophysics Data System (ADS)

    Hu, Guoqing; Song, Kui; Zhang, Li

    2010-11-01

    The problem of controlling the droplet motions in multiphase flows on the microscale has gained increasing attention because the droplet-based microfluidic devices provide great potentials for chemical/biological applications such as drug discovery, chemical kinetics study, material synthesis, and DNA/cell assays. It is critical to understand the relevant physics on droplet hydrodynamics and thus control the generation, motion, splitting, and coalescence of droplets in complex microfluidic networks. The operation of those applications sometimes requires the arrival of droplets from different branch microchannels at a designated location within a transit time. We propose a simple design for interconnected microfluidic devices that implement the feedback mechanism to synchronize the droplet motion via a passive way. Numerical simulations using the Volume of Fluid (VOF) algorithm are conducted to investigate the time-dependent dynamics of droplets in both gas-liquid and liquid-liquid systems. An analytical mode based on the electronic-hydraulic analogy is also developed to describe the transit behavior of the droplet traffic. Both the numerical and theoretical results agree well with the corresponding experimental results. Furthermore, we optimize the microfluidic networks to control the motion of a series of droplets.

  8. The Interconnected Model of Professional Growth as a Means to Assess the Development of a Mathematics Teacher

    ERIC Educational Resources Information Center

    Witterholt, Martha; Goedhart, Martin; Suhre, Cor; van Streun, Anno

    2012-01-01

    In this qualitative study we used a case study approach to observe and analyse a mathematics teacher who was challenged to redesign her lessons during network meetings with colleagues. Changes in practical knowledge are described by means of concept maps and semi-structured interviews. We applied cycles of change from the Interconnected Model of…

  9. Modified FDR Controlling Procedure for Multi-Stage Analyses

    PubMed Central

    Tuglus, Catherine; van der Laan, Mark J.

    2009-01-01

    Multiple testing has become an integral component in genomic analyses involving microarray experiments where a large number of hypotheses are tested simultaneously. However, before applying more computationally intensive methods, it is often desirable to complete an initial truncation of the variable set using a simpler and faster supervised method such as univariate regression. Once such a truncation is completed, multiple testing methods applied to any subsequent analysis no longer control the appropriate Type I error rates. Here we propose a modified marginal Benjamini & Hochberg step-up FDR controlling procedure for multi-stage analyses (FDR-MSA), which correctly controls Type I error in terms of the entire variable set when only a subset of the initial set of variables is tested. The method is presented with respect to a variable importance application. As the initial subset size increases, we observe convergence to the standard Benjamini & Hochberg step-up FDR controlling multiple testing procedures. We demonstrate the power and Type I error control through simulation and application to the Golub Leukemia data from 1999. PMID:19222379

  10. Multi-stage FE simulation of hot ring rolling

    NASA Astrophysics Data System (ADS)

    Wang, C.; Geijselaers, H. J. M.; van den Boogaard, A. H.

    2013-05-01

    As a unique and important member of the metal forming family, ring rolling provides a cost effective process route to manufacture seamless rings. Applications of ring rolling cover a wide range of products in aerospace, automotive and civil engineering industries [1]. Above the recrystallization temperature of the material, hot ring rolling begins with the upsetting of the billet cut from raw stock. Next a punch pierces the hot upset billet to form a hole through the billet. This billet, referred to as preform, is then rolled by the ring rolling mill. For an accurate simulation of hot ring rolling, it is crucial to include the deformations, stresses and strains from the upsetting and piercing process as initial conditions for the rolling stage. In this work, multi-stage FE simulations of hot ring rolling process were performed by mapping the local deformation state of the workpiece from one step to the next one. The simulations of upsetting and piercing stages were carried out by 2D axisymmetric models using adaptive remeshing and element erosion. The workpiece for the ring rolling stage was subsequently obtained after performing a 2D to 3D mapping. The commercial FE package LS-DYNA was used for the study and user defined subroutines were implemented to complete the control algorithm. The simulation results were analyzed and also compared with those from the single-stage FE model of hot ring rolling.

  11. Controllability in Multi-Stage Laser Ion Acceleration

    NASA Astrophysics Data System (ADS)

    Kawata, S.; Kamiyama, D.; Ohtake, Y.; Barada, D.; Ma, Y. Y.; Kong, Q.; Wang, P. X.; Gu, Y. J.; Li, X. F.; Yu, Q.

    2015-11-01

    The present paper shows a concept for a future laser ion accelerator, which should have an ion source, ion collimators, ion beam bunchers and ion post acceleration devices. Based on the laser ion accelerator components, the ion particle energy and the ion energy spectrum are controlled, and a future compact laser ion accelerator would be designed for ion cancer therapy or for ion material treatment. In this study each component is designed to control the ion beam quality. The energy efficiency from the laser to ions is improved by using a solid target with a fine sub-wavelength structure or a near-critical density gas plasma. The ion beam collimation is performed by holes behind the solid target or a multi-layered solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching are successfully realized by a multi-stage laser-target interaction. A combination of each component provides a high controllability of the ion beam quality to meet variable requirements in various purposes in the laser ion accelerator. The work was partly supported by MEXT, JSPS, ASHULA project/ ILE, Osaka University, CORE (Center for Optical Research and Education, Utsunomiya University, Japan), Fudan University and CDI (Creative Dept. for Innovation) in CCRD, Utsunomiya University.

  12. ''Theta gun,'' a multistage, coaxial, magnetic induction projectile accelerator

    SciTech Connect

    Burgess, T.J.; Duggin, B.W.; Cowan, M. Jr.

    1985-11-01

    We experimentally and theoretically studied a multistage coaxial magnetic induction projectile accelerator. We call this system a ''theta gun'' to differentiate it from other coaxial accelerator concepts such as the mass driver. We conclude that this system can theoretically attain railgun performance only for large caliber or very high injection velocity and, even then, only for long coil geometry. Our experiments with a three-stage, capactor bank-driven accelerator are described. The experiments are modeled with a 1-1/2 dimensional equivalent circuit-hydrodynamics code which is also described. We derive an expression for the conditions of coaxial accelerator-railgun ''velocity breakeven'' in the absence of ohmic and hydrodynamic effects. This, in conjunction with an expression for the magnetic coupling coefficient, defines a set of geometric relations which the coaxial system must simultaneously satisfy. Conclusions concerning both the existence and configuration of a breakeven coaxial system follow from this requirement. The relative advantages and disadvantages of the coaxial induction projectile accelerator, previously cited in the literature, are critiqued from the viewpoint of our analysis and experimental results. We find that the advantages vis-a-vis the railgun have been overstated. 13 refs., 17 figs.

  13. Multi-stage combustion using nitrogen-enriched air

    DOEpatents

    Fischer, Larry E.; Anderson, Brian L.

    2004-09-14

    Multi-stage combustion technology combined with nitrogen-enriched air technology for controlling the combustion temperature and products to extend the maintenance and lifetime cycles of materials in contact with combustion products and to reduce pollutants while maintaining relatively high combustion and thermal cycle efficiencies. The first stage of combustion operates fuel rich where most of the heat of combustion is released by burning it with nitrogen-enriched air. Part of the energy in the combustion gases is used to perform work or to provide heat. The cooled combustion gases are reheated by additional stages of combustion until the last stage is at or near stoichiometric conditions. Additional energy is extracted from each stage to result in relatively high thermal cycle efficiency. The air is enriched with nitrogen using air separation technologies such as diffusion, permeable membrane, absorption, and cryogenics. The combustion method is applicable to many types of combustion equipment, including: boilers, burners, turbines, internal combustion engines, and many types of fuel including hydrogen and carbon-based fuels including methane and coal.

  14. The Manihiki Plateau—A multistage volcanic emplacement history

    NASA Astrophysics Data System (ADS)

    Pietsch, Ricarda; Uenzelmann-Neben, Gabriele

    2015-09-01

    The formation history of the Manihiki Plateau, a Large Igneous Province, is poorly understood. New high-resolution seismic reflection data across the High Plateau, the largest edifice of the Manihiki Plateau, provide evidence for multistage magmatic emplacement. Improved data quality allows for an identification of an earlier volcanic phase, the initial formation phase (>125 Ma), in addition to the previously known volcanic formation phases: the expansion phase (125-116) formerly called main-phase, and the secondary volcanic phase (100-65 Ma). This enhances the understanding of the emplacement scenario. An intrabasement reflection band IB1 reveals the end of initial volcanic formation and forms the nucleus of the High Plateau. This feature provides indications that it continued beyond the Manihiki Scarp and thus supports the hypothesis of an extension of the Manihiki Plateau to the East during the initial formation and expansion phases. The expansion phase is characterized by massive volcanic outpourings leveling and extending the basement throughout the High Plateau and the neighboring Western Plateaus, which in contrast shows massive tectonic alteration. Extrusion centers formed within the secondary volcanic phase (ending ˜65 Ma) are mainly concentrated along the margins of the High Plateau, suggesting the magmatic sources shifted from those being related to the initial emplacement and expansion phases of the High Plateau to induced volcanism at the tectonically altered margins.

  15. Dynamics of Multistage Gear Transmission with Effects of Gearbox Vibrations

    NASA Technical Reports Server (NTRS)

    Choy, F. K.; Tu, Y. K.; Zakrajsek, J. J.; Townsend, Dennis P.

    1990-01-01

    A comprehensive approach is presented in analyzing the dynamic behavior of multistage gear transmission systems with the effects of gearbox induced vibrations and mass imbalances of the rotor. The modal method, with undamped frequencies and planar mode shapes, is used to reduce the degrees of freedom of the gear system for time-transient dynamic analysis. Both the lateral and torsional vibration modes of each rotor-bearing-gear stage as well as the interstage vibrational characteristics are coupled together through localized gear mesh tooth interactions. In addition, gearbox vibrations are also coupled to the rotor-bearing-gear system dynamics through bearing support forces between the rotor and the gearbox. Transient and steady state dynamics of lateral and torsional vibrations of the geared system are examined in both time and frequency domains to develop interpretations of the overall modal dynamic characteristics under various operating conditions. A typical three-stage geared system is used as an example. Effects of mass imbalance and gearbox vibrations on the system dynamic behavior are presented in terms of modal excitation functions for both lateral and torsional vibrations. Operational characteristics and conclusions are drawn from the results presented.

  16. Calculation of Multistage Turbomachinery Using Steady Characteristic Boundary Conditions

    NASA Technical Reports Server (NTRS)

    Chima, Rodrick V.

    1998-01-01

    A multiblock Navier-Stokes analysis code for turbomachinery has been modified to allow analysis of multistage turbomachines. A steady averaging-plane approach was used to pass information between blade rows. Characteristic boundary conditions written in terms of perturbations about the mean flow from the neighboring blade row were used to allow close spacing between the blade rows without forcing the flow to be axisymmetric. In this report the multiblock code is described briefly and the characteristic boundary conditions and the averaging-plane implementation are described in detail. Two approaches for averaging the flow properties are also described. A two-dimensional turbine stator case was used to compare the characteristic boundary conditions with standard axisymmetric boundary conditions. Differences were apparent but small in this low-speed case. The two-stage fuel turbine used on the space shuttle main engines was then analyzed using a three-dimensional averaging-plane approach. Computed surface pressure distributions on the stator blades and endwalls and computed distributions of blade surface heat transfer coefficient on three blades showed very good agreement with experimental data from two tests.

  17. Multi-stage methodology to detect health insurance claim fraud.

    PubMed

    Johnson, Marina Evrim; Nagarur, Nagen

    2016-09-01

    Healthcare costs in the US, as well as in other countries, increase rapidly due to demographic, economic, social, and legal changes. This increase in healthcare costs impacts both government and private health insurance systems. Fraudulent behaviors of healthcare providers and patients have become a serious burden to insurance systems by bringing unnecessary costs. Insurance companies thus develop methods to identify fraud. This paper proposes a new multistage methodology for insurance companies to detect fraud committed by providers and patients. The first three stages aim at detecting abnormalities among providers, services, and claim amounts. Stage four then integrates the information obtained in the previous three stages into an overall risk measure. Subsequently, a decision tree based method in stage five computes risk threshold values. The final decision stating whether the claim is fraudulent is made by comparing the risk value obtained in stage four with the risk threshold value from stage five. The research methodology performs well on real-world insurance data. PMID:25600704

  18. Reduced models of multi-stage cyclic structures using cyclic symmetry reduction and component mode synthesis

    NASA Astrophysics Data System (ADS)

    Tran, Duc-Minh

    2014-10-01

    Reduced models of multi-stage cyclic structures such as bladed-disk assemblies are developed by using the multi-stage cyclic symmetry reduction and/or component mode synthesis methods. The multi-stage cyclic symmetry reduction consists in writing the equations of the bladed disks, the inter-disk structures, the inter-disk constraints and the whole multi-stage coupled system in terms of the traveling wave coordinates for all the phase indexes of the reference sectors and for all the bladed disks. Several reduced coupled systems are then solved by selecting at each time only one or a few phase indexes for each bladed disk and by applying the cyclic symmetry boundary conditions. On the other hand, component mode synthesis methods are used either independently or in combination with the multi-stage cyclic symmetry reduction to obtain reduced models of the multi-stage structure. Two of them are particularly efficient, that are firstly component mode synthesis methods with interface modes applied on the bladed disks and secondly component mode synthesis methods with traveling wave coordinates applied on the reference sectors.

  19. Changes of Hematological Markers during a Multi-stage Ultra-marathon Competition in the Heat.

    PubMed

    Rama, L M; Minuzzi, L G; Carvalho, H M; Costa, R J S; Teixeira, A M

    2016-02-01

    This study examined the changes in resting hematological variables in ultra-endurance runners throughout a multi-stage ultra-marathon competition, and compared athletes that completed all stages with those that failed to complete at least one stage within the cut-off time of competition. 19 ultra-endurance runners competing in a 230 km multi-stage ultra-marathon, conducted over 5 consecutive days in hot ambient conditions (32-40°C T(max)), volunteered to participate in the study. Each day, whole blood samples were collected prior to stage commencement and analyzed for full cell counts by Coulter counter. Linear increases were observed for leukocytes, monocytes and lymphocytes; with increases until Stage 3 and a decrease thereafter. Granulocytes showed a cubic growth exponent, indicating decrements to baseline after the significant increments until Stage 3. Hemoglobin and hematocrit showed linear decrements throughout the multi-stage ultra-marathon. No changes in erythrocytes and platelets were observed throughout the multi-stage ultra-marathon. Granulocytes, erythrocytes, hemoglobin and hematocrit changes along the multi-stage ultra-marathon differed in runners that completed all stages compared to those who failed to complete at least one stage within the cut-off time. Multi-stage ultra-marathon in the heat has a large impact on hematological responses of ultra-endurance runners associated with altered performance. PMID:26509375

  20. Supramolecular Organic Nanowires as Plasmonic Interconnects.

    PubMed

    Armao, Joseph J; Domoto, Yuya; Umehara, Teruhiko; Maaloum, Mounir; Contal, Christophe; Fuks, Gad; Moulin, Emilie; Decher, Gero; Javahiraly, Nicolas; Giuseppone, Nicolas

    2016-02-23

    Metallic nanostructures are able to interact with an incident electromagnetic field at subwavelength scales by plasmon resonance which involves the collective oscillation of conduction electrons localized at their surfaces. Among several possible applications of this phenomenon, the theoretical prediction is that optical circuits connecting multiple plasmonic elements will surpass classical electronic circuits at nanoscale because of their much faster light-based information processing. However, the placement and coupling of metallic elements smaller than optical wavelengths currently remain a formidable challenge by top-down manipulations. Here, we show that organic supramolecular triarylamine nanowires of ≈1 nm in diameter are able to act as plasmonic waveguides. Their self-assembly into plasmonic interconnects between arrays of gold nanoparticles leads to the bottom-up construction of basic optical nanocircuits. When the resonance modes of these metallic nanoparticles are coupled through the organic nanowires, the optical conductivity of the plasmonic layer dramatically increases from 259 to 4271 Ω(-1)·cm(-1). We explain this effect by the coupling of a hot electron/hole pair in the nanoparticle antenna with the half-filled polaronic band of the organic nanowire. We also demonstrate that the whole hybrid system can be described by using the abstraction of the lumped circuit theory, with a far field optical response which depends on the number of interconnects. Overall, our supramolecular bottom-up approach opens the possibility to implement processable, soft, and low cost organic plasmonic interconnects into a large number of applications going from sensing to metamaterials and information technologies. PMID:26814600