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1

Magnetic damping forces in figure-eight-shaped null-flux coil suspension systems  

Microsoft Academic Search

This paper discusses magnetic damping forces in figure-eight-shaped null-flux coil suspension systems, focusing on the Holloman Maglev rocket system. The paper also discusses simulating the damping plate, which is attached to the superconducting magnet by two short-circuited loop coils interacting with the figure-eight-shaped null-flux coils in the guideway. Closed-form formulas for the magnetic damping coefficient as functions of heave-and-sway displacements

Jianliang He; H. Coffey

1997-01-01

2

Magnetic damping forces in figure-eight-shaped null-flux coil suspension systems  

SciTech Connect

This paper discusses magnetic damping forces in figure-eight-shaped null-flux coil suspension systems, focusing on the Holloman maglev rocket system. The paper also discusses simulating the damping plate, which is attached to the superconducting magnet by two short-circuited loop coils in the guideway. Closed-form formulas for the magnetic damping coefficient as functions of heave-and-sway displacements are derived by using a dynamic circuit model. These formulas are useful for dynamic stability studies.

He, Jianliang; Coffey, H.

1997-08-01

3

Study on figure-eight-shaped coil electrodynamic suspension magnetic levitation systems without cross-connection  

SciTech Connect

Two figure-eight-shaped coils for electrodynamic suspension (EDS) magnetic levitation (MAGLEV) systems without cross-connection are proposed and analyzed. The guideway coils are positioned under the MAGLEV vehicle; they are parallel to the horizontal plane. The interaction of a magnetic module on the vehicle, composed of three or four superconducting (SC) coils, with a guideway module, comprised of two figure-eight coils, is studied by means of the dynamic circuit theory. The currents in the SC coils are supposed to be constant in time while they move as a rigid body, with a constant velocity. Some results are presented and compared with those for a standard side-wall cross-connected system.

Ribani, P.L.; Urbano, N.

2000-01-01

4

Designing with null flux coils  

SciTech Connect

Null flux were suggested by Danby and Powell in the late 1960`s as a useful means for realizing induced lift with little drag. As an array of alternating magnets is translated past a set of null flux coils, the currents induced in these coils act to vertically center the magnets on those coils. At present, one Japanese MAGLEV system company and two American-based companies are employing either null flux or flux eliminating coils in their design for high speed magnetically levitated transportation. The principle question addressed in paper is: what is the proper choice of coil length to magnet length in a null flux system? A generic analysis in the time and frequency domain is laid out with the intent of showing the optimal design specification in terms of coil parameters.

Davey, K.R. [American Electromechanics, New Smyrna Beach, FL (United States)] [American Electromechanics, New Smyrna Beach, FL (United States)

1997-09-01

5

78 FR 25577 - Safety Zone, Figure Eight Causeway Channel; Figure Eight Island, NC  

Federal Register 2010, 2011, 2012, 2013, 2014

...restricts access to Figure Eight Causeway Channel...this rule will not be significant because: (i) The...rule will not have a significant economic impact on a...transit or anchor in the Figure Eight Causeway Channel...regulation will not have a significant impact on a...

2013-05-02

6

Eccentric figure-eight coils for transcranial magnetic stimulation.  

PubMed

Previously we proposed an eccentric figure-eight coil that can cause threshold stimulation in the brain at lower driving currents. In this study, we performed numerical simulations and magnetic stimulations to healthy subjects for evaluating the advantages of the eccentric coil. The simulations were performed using a simplified spherical brain model and a realistic human brain model. We found that the eccentric coil required a driving current intensity of approximately 18% less than that required by the concentric coil to cause comparable eddy current densities within the brain. The eddy current localization of the eccentric coil was slightly higher than that of the concentric coil. A prototype eccentric coil was designed and fabricated. Instead of winding a wire around a bobbin, we cut eccentric-spiral slits on the insulator cases, and a wire was woven through the slits. The coils were used to deliver magnetic stimulation to healthy subjects; among our results, we found that the current slew rate corresponding to motor threshold values for the concentric and eccentric coils were 86 and 78?A/µs, respectively. The results indicate that the eccentric coil consistently requires a lower driving current to reach the motor threshold than the concentric coil. Future development of compact magnetic stimulators will enable the treatment of some intractable neurological diseases at home. Bioelectromagnetics. 35:55-65, 2015. © 2014 Wiley Periodicals, Inc. PMID:25399864

Sekino, Masaki; Ohsaki, Hiroyuki; Takiyama, Yoshihiro; Yamamoto, Keita; Matsuzaki, Taiga; Yasumuro, Yoshihiro; Nishikawa, Atsushi; Maruo, Tomoyuki; Hosomi, Koichi; Saitoh, Youichi

2015-01-01

7

Rational harmonic figure-eight actively-passively mode-locked erbium-doped fiber laser  

NASA Astrophysics Data System (ADS)

The nonlinear optical loop mirror (NOLM) is used as a saturable absorbed to reshape pulses. Experimentally, an actively mode-locked erbium-doped fiber ring laser with figure-eight structure is set up. 2 ? 4 order harmonic pulse train with stable amplitude has been obtained when the RF modulation frequency is about 2.5 GHz.

Wang, Zhaoying; Yu, Zhenhong; Gao, Peiliang; Yang, Tianxin; Zhang, Ruifeng; Jia, Dongfang; Li, Shichen

2003-05-01

8

Cross-connection control and backflow prevention  

SciTech Connect

We discuss the elimination of potable-water contamination through backflow prevention, and present the elements of a comprehensive cross-connection control program currently in use at Lawrence Livermore National Laboratory (LLNL). This discussion includes the structure, objectives, practices, and policies which drive the LLNL program, along with typical examples of cross-connections. In our program, we emphasize that two types of cross-connections, inlet and pressure, should be eliminated to prevent backflow of contaminated water into potable systems. We also present material gathered from available literature on the theory of backsiphonage and backpressure that will provide concepts to form an effective cross-connection control program.

Mosovsky, J.A.

1984-04-26

9

Water Treatment Technology - Cross-Connections.  

ERIC Educational Resources Information Center

One of twelve water treatment technology units, this student manual on cross connections provides instructional materials for two competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on cross connections terminology and control devices. For each…

Ross-Harrington, Melinda; Kincaid, G. David

10

Vector nature of multi-soliton patterns in a passively mode-locked figure-eight fiber laser.  

PubMed

The vector nature of multi-soliton dynamic patterns was investigated in a passively mode-locked figure-eight fiber laser based on the nonlinear amplifying loop mirror (NALM). By properly adjusting the cavity parameters such as the pump power level and intra-cavity polarization controllers (PCs), in addition to the fundamental vector soliton, various vector multi-soliton regimes were observed, such as the random static distribution of vector multiple solitons, vector soliton cluster, vector soliton flow, and the state of vector multiple solitons occupying the whole cavity. Both the polarization-locked vector solitons (PLVSs) and the polarization-rotating vector solitons (PRVSs) were observed for fundamental soliton and each type of multi-soliton patterns. The obtained results further reveal the fundamental physics of multi-soliton patterns and demonstrate that the figure-eight fiber lasers are indeed a good platform for investigating the vector nature of different soliton types. PMID:24921311

Ning, Qiu-Yi; Liu, Hao; Zheng, Xu-Wu; Yu, Wei; Luo, Ai-Ping; Huang, Xu-Guang; Luo, Zhi-Chao; Xu, Wen-Cheng; Xu, Shan-Hui; Yang, Zhong-Min

2014-05-19

11

Calculation of motion induced eddy current forces in null flux coils  

SciTech Connect

Time dependent motion induced eddy current forces can be quite difficult to compute. The movement of null flux coils between magnets is approached using a coupled boundary element-circuit approach to compute the forces on the structure. The technique involves treating the magnets as a separate circuit whose current is dictated by the product of the magnet thickness and the working coercivity. The mutual inductance between the windows of the moving null flux coil and the stationary equivalent magnet coil hold the key for predicting lift, guidance, and drag forces on the coil. The rate of change of these inductances with respect to position determines the forces and currents. A steady state approximation to these forces is derived in addition to a numerical simulation when the steady state assumption is invalid. The results compare favorably to laboratory results from a 4 ft. diameter experimental test wheel.

Davey, K.; Morris, T. [American Maglev, Inc., Edgewater, FL (United States)] [American Maglev, Inc., Edgewater, FL (United States); Shaaf, J. [BDM Federal, Inc., Huntsville, AL (United States)] [BDM Federal, Inc., Huntsville, AL (United States); Rote, D. [Argonne National Lab., IL (United States)] [Argonne National Lab., IL (United States)

1995-11-01

12

Numerical search for periodic solutions in the vicinity of the figure-eight orbit: slaloming around singularities on the shape sphere  

NASA Astrophysics Data System (ADS)

We present the results of a numerical search for periodic orbits with zero angular momentum in the Newtonian planar three-body problem with equal masses focused on a (narrow) search window bracketing the figure-eight initial conditions. We found eleven solutions that can be described as some power of the "figure-eight" solution in the sense of the topological classification method. One of these solutions, with the seventh power of the "figure-eight", is a choreography. We show numerical evidence of its stability.

Šuvakov, Milovan

2014-08-01

13

Intelligent optical networking with photonic cross connections  

NASA Astrophysics Data System (ADS)

Optical amplification and dense wavelength division multiplexing (DWDM) have fundamentally changed optical transport networks. Now that these technologies are widely adopted, the bottleneck has moved from the outside line plant to nodal central offices, where electrical switching equipment has not kept pace. While OEO technology was (and still is) necessary for grooming and traffic aggregation, the transport network has dramatically changed, requiring a dramatic rethinking of how networks need to be designed and operated. While todays transport networks carry remarkable amounts of bandwidth, their optical layer is fundamentally static and provides for only simple point-to-point transport. Efficiently managing the growing number of wavelengths can only be achieved through a new breed of networking element. Photonic switching systems (PSS) can efficiently execute these functions because they are bit rate, wavelength, and protocol transparent. With their all-optical switch cores and interfaces, PSS can switch optical signals at various levels of granularity wavelength, sub band, and composite DWDM fiber levels. Though cross-connect systems with electrical switch cores are available, they perform these functions at very high capital costs and operational inefficiencies. This paper examines enabling technologies for deployment of intelligent optical transport networks (OTN), and takes a practical perspective on survivability architecture migration and implementation issues.

Ceuppens, L.; Jerphagnon, Olivier L.; Lang, Jonathan; Banerjee, Ayan; Blumenthal, Daniel J.

2002-09-01

14

Dual-keel electrodynamic Maglev system  

SciTech Connect

This paper introduces a new concept for an electrodynamic-suspension maglev system that has a dual-keel arrangement. Each keel consists of a row of superconducting magnets aboard the vehicle. The keels move in troughs in the guideway that are each lined with pairs of figure-eight-shaped null-flux coils. Each pair of null-flux coils is cross-connected to produce null-flux suspension and guidance force. The cross-connected figure-eight null-flux coils in each trough are also energized by a three-phase power supply to produce propulsive force. Preliminary analysis shows that the new system has many advantages over other EDS systems in terms of system performance and dynamic stability.

He, Jianliang; Rote, D.M.; Wang, Zian; Coffey, H.T.

1995-12-31

15

Dual-keel electrodynamic maglev system  

DOEpatents

A propulsion and stabilization system is disclosed with a plurality of superconducting magnetic devices affixed to the dual-keels of a vehicle, where the superconducting magnetic devices produce a magnetic field when energized. The system also includes a plurality of figure-eight shaped null-flux coils affixed to opposing vertical sides of slots in a guideway. The figure-eight shaped null-flux coils are vertically oriented, laterally cross-connected in parallel, longitudinally connected in series, and continue the length of the vertical slots providing levitation and guidance force. An external power source energizes the figure-eight shaped null-flux coils to create a magnetic traveling wave that interacts with the magnetic field produced by the superconducting magnets to impart motion to the vehicle. 6 figs.

He, J.L.; Wang, Z.; Rote, D.M.; Coffey, H.T.; Hull, J.R.; Mulcahy, T.M.; Cal, Y.

1996-12-24

16

Dual-keel electrodynamic maglev system  

DOEpatents

A propulsion and stabilization system with a plurality of superconducting magnetic devices affixed to the dual-keels of a vehicle, where the superconducting magnetic devices produce a magnetic field when energized. The system also includes a plurality of figure-eight shaped null-flux coils affixed to opposing vertical sides of slots in a guideway. The figure-eight shaped null-flux coils are vertically oriented, laterally cross-connected in parallel, longitudinally connected in series, and continue the length of the vertical slots providing levitation and guidance force. An external power source energizes the figure-eight shaped null-flux coils to create a magnetic traveling wave that interacts with the magnetic field produced by the superconducting magnets to impart motion to the vehicle.

He, Jianliang (Naperville, IL); Wang, Zian (Downers Grove, IL); Rote, Donald M. (Lagrange, IL); Coffey, Howard T. (Darien, IL); Hull, John R. (Westmont, IL); Mulcahy, Thomas M. (Western Springs, IL); Cal, Yigang (Woodridge, IL)

1996-01-01

17

Performance evaluation of optical cross-connected networks  

NASA Astrophysics Data System (ADS)

The transmission performance of regular two-connected multi-hop transparent optical networks in uniform traffic under hot-potato, single-buffer deflection routing schemes is evaluated. Manhattan Street (MS) Network and ShuffleNet (SN) are compared in terms of bit error rate (BER) and packet error rate (PER). We implement a novel strategy of analysis, in which the transmission performance evaluation is linked to the traffic randomness of the networks. Amplifier spontaneous emission (ASE) noise, and device-induced crosstalk severely limit the characteristics of the network, such as propagation distance, sustainable traffic, and bit- rate. To improve the teletraffic/transmission performance of regular two-connected optical networks a hybrid semi- transparent store-and-forward node architecture is presented. MS and SN are compared in terms of average queueing delay, queue size, propagation delay, throughput, and BER. Packets are stored just in the case of conflict to avoid deflection, otherwise they transparently traverse the node (transparent cut-through routing) without optical-electronic conversion. This architecture performs well, in terms of throughput, propagation delay and BER. It is also shown that by combining deflection routing with the store-and-forward scheme the network can accommodate two different bit- rate. This suggests that the proposed hybrid scheme may have good potential for future multimedia networks. In addition, the steady state behavior of two-connected mesh packet-switched optical networks under wavelength translation scheme (WT) is analyzed. It is shown that wavelength translation mitigates the blocking of cells substantially in cross-connected networks. By increasing the number of wavelengths and employing wavelength translation the probability of deflection can be reduced which, in turn, leads to a significant improvement in the teletraffic performance of the network.

Castanon Avila, Gerardo Antonio

1998-07-01

18

Cross-connection detection in Australian dual reticulation systems by monitoring inherent fluorescent organic matter  

Microsoft Academic Search

New housing developments are now commonly incorporating dual reticulation water systems for the redistribution of recycled water back to households for non-potable use. Within such distribution systems is the potential for cross-connections between recycled and drinking water pipelines, and a number of such events have been documented both in Australia and internationally. While many cross-connections are unlikely to present a

A. C. Hambly; R. K. Henderson; A. Baker; R. M. Stuetz; S. J. Khan

2012-01-01

19

A cross-connected components-based layout analysis algorithm for Chinese business card  

Microsoft Academic Search

In this paper, a cross-connected components-based layout analysis algorithm for Chinese business card (CBC) is presented. The major aim of our scheme is to extract important personal information such as the holder's name, title, address, phone number, etc. from the CBC image. Though much work has been done on layout analysis at present, this task is still very difficult considering

Huiying Zhu; Yuexian Zou

2008-01-01

20

Comparison of Wavelength-Selective Cross-Connect Architectures for Reconfigurable All-Optical Networks  

Microsoft Academic Search

The scalability, modularity and optical transport characteristics of various wavelength-selective cross-connect (WSXC) node architectures for reconfigurable all-optical networks are presented. In particular, these WSXC architectures are analyzed as the add-drop ratio and degree of the node are increased.

V. Kaman; S. Yuan; O. Jerphagnon; R. J. Helkey; J. E. Bowers

2006-01-01

21

Three-dimensional MEMS photonic cross-connect switch design and performance  

Microsoft Academic Search

Photonic cross-connects (PXC) play a key role in all-optical transparent networks. In this paper, the optical design and modeling of a three-dimensional microelectromechanical system (3-D MEMS) based optical switch are discussed. Basic design rules and considerations are reviewed and used to determine the optimum configuration for free-space optical switches with more than 300 ports. The optical performance of a 256

Xuezhe Zheng; Volkan Kaman; Shifu Yuan; Yuanjian Xu; Olivier Jerphagnon; Adrian Keating; Robert C. Anderson; Henrik N. Poulsen; Bin Liu; James R. Sechrist; Chandrasekhar Pusarla; Roger Helkey; Daniel J. Blumenthal; John E. Bowers

2003-01-01

22

A cyclic MUX-DMUX photonic cross-connect architecture for transparent waveband optical networks  

Microsoft Academic Search

A novel photonic cross-connect (PXC) configuration with cyclic multiplexers and demultiplexers (DMUXs) is proposed for realizing dynamic switching and transparent add-drop in waveband dense wavelength-division-multiplexed networks. The PXC architecture allows for a flexible operation while maintaining low optical losses for express wavebands and add-drop wavelengths. The drop functionality of this architecture is demonstrated using an integrated cyclic optical DMUX and

Volkan Kaman; Xuezhe Zheng; Olivier Jerphagnon; Chandrasekhar Pusarla; Roger J. Helkey; John E. Bowers

2004-01-01

23

Combining circuit and packet switching using a large port-count optical cross-connect for data center networks  

NASA Astrophysics Data System (ADS)

The exponential increase in the data center network traffic has posed new challenges for achieving high throughput, low latency and energy consumption. To address these challenges, this paper presents a novel scheme that combines optical circuit and packet switching technologies together in a single optical cross-connect for data center networks. By utilizing fast tunable linecards and parallel array waveguide grating routers, the optical cross-connect can offer low latency, large scalability and high throughput in datacenter networks. A scheduling technique is designed to simultaneously accommodate circuit switching and packet switching in the optical cross-connect. The physical performance of this optical cross-connect in circuit and packet switching modes is investigated by experiments. In addition, the network performance of the optical cross-connect is evaluated through simulations under a mixed circuit/packet-switched traffic pattern. Results show that the network performance of the optical cross-connect does not degrade significantly with an increase in the number of racks, but it is affected by the circuit-switched traffic proportion.

Huang, Qirui; Yeo, Yong-Kee; Zhou, Luying

2012-10-01

24

Cascadability of large-scale 3-D MEMS-based low-loss photonic cross-connects  

Microsoft Academic Search

The performance of cascaded low-loss (<3.5 dB) 256×256 three-dimensional microelectromechanical system (3-D MEMS) photonic cross-connects (PXCs) is experimentally investigated in a recirculating loop. After 60 transitions through the PXC, a power penalty of 1.7 dB is observed, which is attributed to the accumulation of the low polarization-dependent loss in the optical switch. The use of 3-D MEMS PXCs as a

Volkan Kaman; Xuezhe Zheng; Shifu Yuan; Jim Klingshirn; Chandrasekhar Pusarla; Roger J. Helkey; Olivier Jerphagnon; John E. Bowers

2005-01-01

25

Reconfigurable all-fiber all-optical cross-connect node using synthesized fiber Bragg gratings for both demultiplexing and switching  

Microsoft Academic Search

Wavelength-routed optical networks will use all-optical cross-connects (OXC) to establish transparent optical paths through the network. Most OXC architectures are based on using a combination of (de)multiplexers, space switches, optical filters, and power splitters (combiners). In principle, the space division switching can be replaced with a combination of power splitting and tunable wavelength filters. However, such architectures suffer from large

D. R. Hjelme; H. Storoy; J. Skaar

1998-01-01

26

Performance and applications of a large port-count and low-loss photonic cross-connect system for optical networks  

Microsoft Academic Search

We report a 256×256 photonic cross-connect system including 1:1 protection and under 7dB insertion loss in the O and C bands. Some performance metrics are more or less important depending on the application but high reliability and low insertion loss are common requirements for network deployment. Although a 3D-MEMS based PXC is highly linear and transparent, its impact on the

O. Jerphagnon; R. Anderson; A. Chojnacki; R. Helkey; W. Fant; V. Kaman; A. Keating; Bin Liu; C. Pusarla; J. R. Sechrist; D. Xu; Shifu Yuan; Xuezhe Zheng

2002-01-01

27

A 32 x 10 Gb\\/s DWDM metropolitan network demonstration using wavelength-selective photonic cross-connects and narrow-band EDFAs  

Microsoft Academic Search

The feasibility of a 32×10 Gb\\/s dense wavelength-division-multiplexed (DWDM) all-optical short-reach metropolitan network using dynamically reconfigurable three-dimensional microelectromechanical-system-based wavelength-selective photonic cross-connects (WSPXC) is experimentally investigated. Full DWDM amplification at the high-capacity node is performed with low-cost narrow-band erbium-doped fiber amplifiers whose channel gain variation is compensated per span using the inherent channel equalization capability of the WSPXC. With Reed-Solomon forward

Volkan Kaman; Xuezhe Zheng; Shifu Yuan; Jim Klingshirn; Chandrasekhar Pusarla; Roger J. Helkey; Olivier Jerphagnon; John E. Bowers

2005-01-01

28

Acetabular retroversion as a rare cause of chronic hip pain: recognition of the “figure-eight” sign  

Microsoft Academic Search

While well-recognized in the orthopedic literature as a cause of chronic hip pain, acetabular retroversion has not been specifically\\u000a described in the radiologic literature. Acetabular retroversion represents a particular form of hip dysplasia characterized\\u000a by abnormal posterolateral orientation of the acetabulum. This pathophysiology predisposes the individual to subsequent anterior\\u000a impingement of the femoral neck upon the anterior acetabular margin and

Kevin P. Banks; David E. Grayson

2007-01-01

29

CROSS-CONNECTIONS COLLEGE OF LAW  

E-print Network

between academic disciplines to address critical societal issues--from family law to counterterrorism. >> The Institute for National Security and Counterterrorism (INSCT)--created in partnership with the Maxwell School and international security and counterterrorism. >> The Institute for the Study of the Judiciary, Politics

McConnell, Terry

30

Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles  

DOEpatents

A propulsion and stabilization system are described comprising a series of coils mounted vertically on the walls of the guideway to provide suspension, lateral guidance, and propulsion of a magnetically levitated vehicle. This system further allows for altering the magnetic field effects by changing the relative position of the loops comprising the coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension. 8 figures.

Rote, D.M.; He, J.; Johnson, L.R.

1994-01-04

31

Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles  

DOEpatents

A propulsion and stabilization system comprising a series of FIG. 8 coils mounted vertically on the walls of the guideway to provide suspension, lateral guidance and propulsion of a magnetically levitated vehicle. This system further allows for altering the magnetic field effects by changing the relative position of the loops comprising the FIG. 8 coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension.

Rote, Donald M. (Lagrange, IL); He, Jianliang (Woodridge, IL); Johnson, Larry R. (Naperville, IL)

1994-01-01

32

Applications of the dynamic circuit theory to Maglev suspension systems  

Microsoft Academic Search

The applications of dynamic circuit theory to electrodynamic suspension (EDS) systems are discussed. Emphasis is placed on the loop-shaped coil and the figure-eight-shaped null-flux coil suspension systems. Mathematical models, including very general force expressions that can be used for the development of computer codes, are provided for each of these suspension systems. The general applications and advantages of the dynamic

Jian Liang He; Donald M. Rote; Howard T. Coffey

1993-01-01

33

EVALUATION OF FIGURE-EIGHT MAZE ACTIVITY AND GENERAL BEHAVIORAL DEVELOPMENT FOLLOWING PRENATAL EXPOSURE TO FORTY CHEMICALS: EFFECTS OF CYTOSINE ARABINOSIDE, DINOCAP, NITROFEN, AND VITAMIN A  

EPA Science Inventory

The present report describes the effects of prenatal administration exposure of a large number of compounds on the locomotor activity levels of mice. The effects of these treatments on the postnatal growth, viability, morphology and reproductive function from the first experiment...

34

CANR | Cooperative Extension | REC | UD Home | UD Directory | UD Daily | Find It (A-Z) | BUDDY | Room Schedules | Figure Eight Thu, Dec-06-07 Fall Faculty  

E-print Network

Health Rocks! Preventing Pedestrian Injuries Halloween Safety Tips Avoiding the AM Rush Brown Bag Lunch Bulgarian vets visit UD to learn 'Delaware Model' for containing bird flu Panel sees partnerships as key

Sparks, Donald L.

35

LC-based subwavelength diffractive optical element structures for optical cross-connect applications  

NASA Astrophysics Data System (ADS)

Two novel concepts of liquid crystal (LC) diffractive structures are introduced and analyzed. Both structures are aimed at overcoming the fringing field effect in thin LC cells while allowing sufficiently large phase dynamic range to be attained. The first structure is a combination of a sub-wavelength metal grating configuration, combined with a built-in reflective, blazed grating structure and a uniform thickness LC cell. The reflective blazed grating provides a periodic, linear phase modulation, while the metal-strip sub-wavelength grating acts as a polarization-sensitive transparent multi-electrode element. The thin liquid crystal layer provides the spatially-varying dynamic phase profile. It is shown that this structure allows a triple-beam deflection operation. A diffraction analysis based on the LC director simulation shows a diffraction efficiency of over 66% in all three diffraction angles. A detailed high-spatial resolution analysis of the fringing field effect on the LC alignment for this structure is described. The second configuration is based on a built-in blazed diffractive grating, composed of two optical substrates with different refractive indices and a uniform-thickness LC layer, enclosed in a Fabry-Perot cavity. It is shown that this structure which overcomes the difficulties of LC alignment and fringing field effects in hybrid, blazed LC-glass structures, allows a dynamic switching of a laser beam with a diffraction efficiency exceeding 75%.

Apter, Boris; Acco, Shy; Efron, Uzi

2001-11-01

36

Transmission of respiratory rhythm: midline-crossing connections at the level of the phrenic motor nucleus?  

PubMed

We used three methods to test for the existence of transmission of respiratory rhythm across the midline at the level of the phrenic motor nucleus in rats using the in situ preparation over a range of ages from neonatal to juvenile. Stimulus-triggered averages of phrenic activity for stimuli applied to one side of the spinal cord at C2 and C3 produced large peaks in the ipsilateral averages but no discernible peaks in the contralateral averages, unless the stimulating microelectrode was placed close to the midline in the ventral funiculus. Following mid-sagittal section of the medulla, respiratory rhythm was maintained for all ages, with bursts occurring on one phrenic nerve that were absent on the other. Cross-correlations of left and right phrenic discharges displayed peaks indicative of short time-scale synchronisation before the medullary transections but not afterwards. We therefore could not find evidence for transmission of respiratory rhythm across the midline at the phrenic motoneurone level; we did find evidence that that transmission via ipsilaterally descending axons of medullary phrenic pre-motor neurones is present at all ages. PMID:16301004

Duffin, James; Li, Yan Mei

2006-09-28

37

Microsecond regime optical cross connect: 32 port to 32 port scalable device  

NASA Astrophysics Data System (ADS)

Presented here is a 32 × 32 optical switch for telecommunications applications capable of reconfiguring at speeds of up to 12 microseconds. The free space switching mechanism in this interconnect is a digital micromirror device (DMD) consisting of a 2D array of 10.8?m mirrors optimized for implementation at 1.55?m. Hinged along one axis, each micromirror is capable of accessing one of two positions in binary fashion. In general reflection based applications this corresponds to the ability to manifest only two display states with each mirror, but by employing this binary state system to display a set of binary amplitude holograms, we are able to access hundreds of distinct locations in space. We previously demonstrated a 7 × 7 switch employing this technology, providing a proof of concept device validating our initial design principles but exhibiting high insertion and wavelength dependent losses. The current system employs 1920 × 1080 DMD, allowing us to increase the number of accessible ports to 32 × 32. Adjustments in imaging, coupling component design and wavelength control were also made in order to improve the overall loss of the switch. This optical switch performs in a bit-rate and protocol independent manner, enabling its use across various network fabrics and data rates. Additionally, by employing a diffractive switching mechanism, we are able to implement a variety of ancillary features such as dynamic beam pick-off for monitoring purposes, beam division for multicasting applications and in situ attenuation control.

Lynn, Brittany; Miles, Alexander; Blanche, Pierre-Alexandre; Wissinger, John; Carothers, Daniel; Norwood, Robert A.; Peyghambarian, N.

2014-03-01

38

Computation of magnetic suspension of maglev systems using dynamic circuit theory  

SciTech Connect

Dynamic circuit theory is applied to several magnetic suspensions associated with maglev systems. These suspension systems are the loop-shaped coil guideway, the figure-eight-shaped null-flux coil guideway, and the continuous sheet guideway. Mathematical models, which can be used for the development of computer codes, are provided for each of these suspension systems. The differences and similarities of the models in using dynamic circuit theory are discussed in the paper. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many electrodynamic suspension system design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper. 15 refs., 7 figs., 1 tab.

He, J.L.; Rote, D.M.; Coffey, H.T.

1991-01-01

39

Applications of the dynamic circuit theory to maglev suspension systems  

SciTech Connect

This paper discusses the applications of dynamic circuit theory to electrodynamic suspension EDS systems. In particular, the paper focuses on the loop-shaped coil and the figure-eight-shaped null-flux coil suspension systems. Mathematical models, including very general force expressions that can be used for the development of computer codes, are provided for each of these suspension systems. General applications and advantages of the dynamic circuit model are summarized. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many EDS maglev design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper to demonstrate the capability of the model.

He, Jian Liang; Rote, D.M.; Coffey, H.T. [Argonne National Lab., IL (United States). Center for Transportation Research

1993-11-01

40

Computation of magnetic suspension of maglev systems using dynamic circuit theory  

NASA Technical Reports Server (NTRS)

Dynamic circuit theory is applied to several magnetic suspensions associated with maglev systems. These suspension systems are the loop-shaped coil guideway, the figure-eight-shaped null-flux coil guideway, and the continuous sheet guideway. Mathematical models, which can be used for the development of computer codes, are provided for each of these suspension systems. The differences and similarities of the models in using dynamic circuit theory are discussed in the paper. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many electrodynamic suspension system design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper.

He, J. L.; Rote, D. M.; Coffey, H. T.

1992-01-01

41

THE EFFECT OF LONG TERM WASTEWATER CROSS-CONNECTION'S EFFECT ON THE BIOFILM OF A SIMULATED WATER DISTRIBUTION SYSTEM  

EPA Science Inventory

Under the current regulations (CFR 503), Class B biosolids may be land applied with certain site restrictions. One method for achieving Class B status is to raise the pH of the sludge to >12 for a minimum of 2 hours with an alkaline material (normally lime). Alternately, a Clas...

42

77 FR 10792 - Self-Regulatory Organizations; Chicago Stock Exchange, Inc.; Notice of Filing and Immediate...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Schedule To Provide for a New Cross Connection Charge and Waive Monthly Fees at its New Facility...provide for certain new cross connection charges and to waive monthly port fees and cross connection charges otherwise applicable to any...

2012-02-23

43

Design of NSLS-II High Order Multipole Correctors  

SciTech Connect

Feasibility studies for two families of corrector magnets for NSLS-II are presented. The first family of magnets are generalizations of figure eight quadrupoles using rotationally symmetric breaks in the return yoke to fit in available space. Properties specific to figure eight magnet are identified. The second type of magnet is a combined sextupole/dipole trim.

Rehak,M.; Danby, G.; Bengtsson, Jo; Jackson, J.; Skaritka, J.; Spataro, C.

2009-05-04

44

Science 101: How Does the Motion of the Earth Affect Our View of the Sun?  

ERIC Educational Resources Information Center

The question examined in this "Science 101" column was inspired by "Find Your School's Analemma" (in this issue). What causes the Sun's apparent position in the sky to trace a figure-eight pattern throughout one year? The analemma, or figure eight pattern that the Sun makes throughout the year, is due to two major…

Robertson, Bill

2014-01-01

45

Adaptive Routing Algorithm for Lambda Switching Networks Stelios Sartzetakis  

E-print Network

converters in real time. For the control of Optical Cross-Connects, the MPLambdaS approach was proposed time. For the control of Optical Cross-Connects (OXC), the MPLambdaS [1] approach was proposed by IETF by IETF, according to which the MPLS traffic engineering control plane is used in Optical Cross Connects

46

Math 205B -Topology February 9, 2007  

E-print Network

Math 205B - Topology Dr. Baez February 9, 2007 Christopher Walker Exercise 58.2. For each Cyclic (k) S1 (R Ã? 0) - Figure Eight (l) R2 - (R+ Ã? 0) - Trivial 1 #12;Exercise 58.4. Let X be the figure the diameter to the center of the circle. Similarly, the map f : X Y can be described as stretching each

Baez, John

47

Theoretical and experimental determination of capstan drive slip error  

Microsoft Academic Search

Cable capstan drives are rotary transmission elements widely used in robot applications because of their low inertia, low backlash, high stiffness and simplicity. The cable in capstan drives is typically wrapped around the input and output drums in a figure-eight pattern and is the principle component for power transmission. In this paper an analytical method is developed for predicting the

Ozgur Baser; E. Ilhan Konukseven

2010-01-01

48

Theoretical and Experimental Determination of the Stiffness Properties of a Capstan Drive  

Microsoft Academic Search

Wire capstan drives are used as rotary transmission elements for their very low (nominally zero) backlash and high stiffness properties. To obtain high stiffness, the cable is typically wrapped around the input and output drum in a figure-eight pattern multiple times. This stiffness can be determined by analyzing the amount of deformation between the cable and the drums and the

Jaime Werkmeister; Alexander Slocum

49

Theoretical and experimental determination of capstan drive stiffness  

Microsoft Academic Search

Cable or metal band capstan drives are used as rotary transmission elements for their very low (nominally zero) backlash and high stiffness properties. Cable drives, in particular, are found in many types of equipment, and to obtain high stiffness, the cable is typically wrapped around the input and output drum in a figure-eight pattern. This paper develops analytical methods for

Jaime Werkmeister; Alexander Slocum

2007-01-01

50

Dipole trapped spheromak in a prolate flux conserver M. R. Brown,a  

E-print Network

are moderate , compact, translatable, sim- ply connected plasma configurations, all of which make them tried a variety of con- ducting boundaries to stabilize the tilt. These included figure-eight coils­dimensional 3D MHD simulation stud- ies motivated by the S-1 experiment ,10 a variety of con- ducting boundaries

Brown, Michael R.

51

NEUROBEHAVIORAL EFFECTS OF TRIADIMEFON, A TRIAZOLE FUNGICIDE, IN MALE AND FEMALE RATS  

EPA Science Inventory

Triadimefon is a widely used systemic fungicide, yet there is little published information on its effects in mammals. This study describes the effects of triadimefon in male and female rats using a functional observational battery (FOB), motor activity (measured in a figure-eight...

52

AUDITORY DEFICITS AND MOTOR DYSFUNCTION FOLLOWING IMINODIPROPIONITRILE ADMINISTRATION IN THE RAT  

EPA Science Inventory

The behavioral effects of 3,3'-iminodipropionitrile (IDPN) were studied using reflex modification of the acoustic startle response and figure-eight maze activity. umber of experiments were conducted with separate groups of adult male Long Evans hooded rats exposed to saline, or 5...

53

7 CFR 1755.910 - RUS specification for outside plant housings and serving area interface systems.  

Code of Federal Regulations, 2010 CFR

...shall be provided with a minimum of 1.8 m (6 ft...terminal to identify special circuits and insulate exposed...cross-connect terminals. The minimum length of cross-connect...be capable of making a minimum of 100 successive connections...occurrence of an open circuit. The test shall...

2010-01-01

54

Design of high density pin board matrix switches for automated main distributing frame systems  

Microsoft Academic Search

High-density pin board matrix switches composed of matrix boards and connecting pins are designed to provide the cross connection function of an automated main distributing frame (AMDF) system. The cross connection is performed by inserting a connecting pin into a through hole on the matrix board. A small economic AMDF system is made possible by using a laminated matrix board

Shigeru Umemura; Tsuneo Kanai; Shuichiro Inagaki; Yasuo Kumakura

1992-01-01

55

Do border crossings contribute to underage motor-vehicle fatalities? An analysis of Michigan border crossings  

Microsoft Academic Search

Abstract.?Currently, Michigan residents can avoid the national drinking age of 21 by crossing into Ontario, where the drinking age is 19. This paper explores the impact that border crossings, connecting areas with different minimum legal drinking ages (MLDA), have on motor-vehicle fatalities. We analyse border crossings connecting Michigan to Ontario as well as to its surrounding states in the period

Steven F. Kreft; Nancy M. Epling

2007-01-01

56

Do Border Crossings Contribute to Underage MotorVehicle Fatalities?  

Microsoft Academic Search

Currently, Michigan residents can avoid the national drinking age of 21 by crossing into Ontario where the drinking age is 19. This paper explores the impact that border crossings, connecting areas with different minimum legal drinking ages (MLDA), have on motor-vehicle fatalities. We analyze border crossings connecting Michigan to Ontario, as well as to its surrounding states in the period

Steven F. Kreft; Nancy M. Epling

2005-01-01

57

Lichen sclerosus in a breast cancer survivor on an aromatase inhibitor: a case report.  

PubMed

Lichen sclerosus is a commonly misdiagnosed disease that is characterized by thinned, hypopigmented, crinkled skin that often forms a figure-eight shape around the vaginal and anal openings. We present a case of advanced lichen sclerosus in a 53-year-old female patient prescribed a nonsteroidal aromatase inhibitor after the excision of a breast cancer tumor. We present a diagnostic approach to lichen sclerosus by recognizing its common figure-eight pattern, and we review the known causes and treatment of lichen sclerosus. Research has shown that lichen sclerosus is more common in low estrogen states, and thus it is logical that aromatase inhibitors could increase a patient's risk for developing this disease. We therefore propose that all patients prescribed aromatase inhibitors undergo regular vulvo-vaginal exams to rule out lichen sclerosus and other hypoestrogen-related vulvo-vaginal problems. PMID:22956445

Potter, Jennifer E; Moore, Kendra A

2013-04-01

58

A symplectic integrator for the symmetry reduced and regularised planar 3-body problem with vanishing angular momentum  

NASA Astrophysics Data System (ADS)

We construct an explicit reversible symplectic integrator for the planar 3-body problem with zero angular momentum. We start with a Hamiltonian of the planar 3-body problem that is globally regularised and fully symmetry reduced. This Hamiltonian is a sum of 10 polynomials each of which can be integrated exactly, and hence a symplectic integrator is constructed. The performance of the integrator is examined with three numerical examples: The figure eight, the Pythagorean orbit, and a periodic collision orbit.

Rose, Danya; Dullin, Holger R.

2013-10-01

59

77 FR 17066 - Proposed Data Collections Submitted for Public Comment and Recommendations  

Federal Register 2010, 2011, 2012, 2013, 2014

...such as water main breaks, cross-connections, back-flow, and pressure fluctuations can result in potential intrusion of microbes and other contaminants that can cause health effects, including acute gastrointestinal and respiratory illness....

2012-03-23

60

77 FR 65894 - Agency Forms Undergoing Paperwork Reduction Act Review  

Federal Register 2010, 2011, 2012, 2013, 2014

...such as water main breaks, cross-connections, back-flow, and pressure fluctuations can result in potential intrusion of microbes and other contaminants that can cause health effects, including acute gastrointestinal illness (AGI) and acute...

2012-10-31

61

76 FR 19362 - Proposed Data Collections Submitted for Public Comment and Recommendations  

Federal Register 2010, 2011, 2012, 2013, 2014

...such as water main breaks, cross-connections, back-flow, and pressure fluctuations can result in potential intrusion of microbes and other contaminants that can cause health effects, including acute gastrointestinal and respiratory illness....

2011-04-07

62

46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.  

Code of Federal Regulations, 2012 CFR

...have instantaneous protection against short circuit for electrical-power circuits and control circuits, the protection sized and located to comply...OSV. (j) Each vessel with duplicate (parallel but cross-connected) power systems...

2012-10-01

63

46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.  

Code of Federal Regulations, 2011 CFR

...have instantaneous protection against short circuit for electrical-power circuits and control circuits, the protection sized and located to comply...OSV. (j) Each vessel with duplicate (parallel but cross-connected) power systems...

2011-10-01

64

46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.  

Code of Federal Regulations, 2013 CFR

...have instantaneous protection against short circuit for electrical-power circuits and control circuits, the protection sized and located to comply...OSV. (j) Each vessel with duplicate (parallel but cross-connected) power systems...

2013-10-01

65

46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.  

Code of Federal Regulations, 2010 CFR

...have instantaneous protection against short circuit for electrical-power circuits and control circuits, the protection sized and located to comply...OSV. (j) Each vessel with duplicate (parallel but cross-connected) power systems...

2010-10-01

66

46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.  

Code of Federal Regulations, 2014 CFR

...have instantaneous protection against short circuit for electrical-power circuits and control circuits, the protection sized and located to comply...OSV. (j) Each vessel with duplicate (parallel but cross-connected) power systems...

2014-10-01

67

78 FR 76350 - Self-Regulatory Organizations; NASDAQ OMX PHLX LLC.; Notice of Filing and Immediate Effectiveness...  

Federal Register 2010, 2011, 2012, 2013, 2014

...releases and product enhancements, as well as testing firm software prior to implementation...cross-connection to either a member firm's direct connection router in Carteret or its co-location cabinet.\\7\\ This...

2013-12-17

68

78 FR 76344 - Self-Regulatory Organizations; NASDAQ OMX BX, Inc.; Notice of Filing and Immediate Effectiveness...  

Federal Register 2010, 2011, 2012, 2013, 2014

...releases and product enhancements, as well as testing firm software prior to implementation...cross-connection to either a member firm's direct connection router in Carteret or its co-location cabinet.\\6\\ This...

2013-12-17

69

78 FR 69485 - Self-Regulatory Organizations; The NASDAQ Stock Market LLC; Notice of Filing and Immediate...  

Federal Register 2010, 2011, 2012, 2013, 2014

...releases and product enhancements, as well as testing firm software prior to implementation...cross-connection to either a member firm's direct connection router in Carteret or its co-location cabinet.\\6\\ NASDAQ...

2013-11-19

70

Application of portable fluorescence spectrophotometry for integrity testing of recycled water dual distribution systems.  

PubMed

Water utilities supplying recycled water to households via a "third-pipe" or "dual reticulation" system have a need for a rapid, portable method to detect cross-connections within potable water reticulation networks. This study evaluates portable fluorimetry as a technique for cross-connection detection in the field. For the first time, an investigation of a full-scale dual reticulation water-recycling network has been carried out to identify cross-connections using a portable fluorimeter. We determined that this can be carried out with a 3 mL water sample, and unlike methods that are currently in use for cross-connection detection, can be achieved quickly without disruption to water flow or availability within the network. It was also revealed that fluorescence trigger values could be established with high levels of confidence by sampling less than 2.5% of the network. Fluorescence analysis was also able to uncover a single, real cross-connection event. As such, this paper is a fundamental demonstration of fluorescence as a reliable, highly portable technique for cross-connection detection within dual reticulation water recycling networks and further establishes the abilities of fluorescence devices as valuable field instruments for water quality monitoring. PMID:25506735

Hambly, Adam C; Henderson, Rita K; Baker, Andy; Stuetz, Richard M; Khan, Stuart J

2015-01-01

71

Physiological modules for generating discrete and rhythmic movements: component analysis of EMG signals  

PubMed Central

A central question in Neuroscience is that of how the nervous system generates the spatiotemporal commands needed to realize complex gestures, such as handwriting. A key postulate is that the central nervous system (CNS) builds up complex movements from a set of simpler motor primitives or control modules. In this study we examined the control modules underlying the generation of muscle activations when performing different types of movement: discrete, point-to-point movements in eight different directions and continuous figure-eight movements in both the normal, upright orientation and rotated 90°. To test for the effects of biomechanical constraints, movements were performed in the frontal-parallel or sagittal planes, corresponding to two different nominal flexion/abduction postures of the shoulder. In all cases we measured limb kinematics and surface electromyographic activity (EMG) signals for seven different muscles acting around the shoulder. We first performed principal component analysis (PCA) of the EMG signals on a movement-by-movement basis. We found a surprisingly consistent pattern of muscle groupings across movement types and movement planes, although we could detect systematic differences between the PCs derived from movements performed in each shoulder posture and between the principal components associated with the different orientations of the figure. Unexpectedly we found no systematic differences between the figure eights and the point-to-point movements. The first three principal components could be associated with a general co-contraction of all seven muscles plus two patterns of reciprocal activation. From these results, we surmise that both “discrete-rhythmic movements” such as the figure eight, and discrete point-to-point movement may be constructed from three different fundamental modules, one regulating the impedance of the limb over the time span of the movement and two others operating to generate movement, one aligned with the vertical and the other aligned with the horizontal. PMID:25620928

Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana Maria; Dan, Bernard; Cheron, Guy; McIntyre, Joseph

2015-01-01

72

Physiological modules for generating discrete and rhythmic movements: component analysis of EMG signals.  

PubMed

A central question in Neuroscience is that of how the nervous system generates the spatiotemporal commands needed to realize complex gestures, such as handwriting. A key postulate is that the central nervous system (CNS) builds up complex movements from a set of simpler motor primitives or control modules. In this study we examined the control modules underlying the generation of muscle activations when performing different types of movement: discrete, point-to-point movements in eight different directions and continuous figure-eight movements in both the normal, upright orientation and rotated 90°. To test for the effects of biomechanical constraints, movements were performed in the frontal-parallel or sagittal planes, corresponding to two different nominal flexion/abduction postures of the shoulder. In all cases we measured limb kinematics and surface electromyographic activity (EMG) signals for seven different muscles acting around the shoulder. We first performed principal component analysis (PCA) of the EMG signals on a movement-by-movement basis. We found a surprisingly consistent pattern of muscle groupings across movement types and movement planes, although we could detect systematic differences between the PCs derived from movements performed in each shoulder posture and between the principal components associated with the different orientations of the figure. Unexpectedly we found no systematic differences between the figure eights and the point-to-point movements. The first three principal components could be associated with a general co-contraction of all seven muscles plus two patterns of reciprocal activation. From these results, we surmise that both "discrete-rhythmic movements" such as the figure eight, and discrete point-to-point movement may be constructed from three different fundamental modules, one regulating the impedance of the limb over the time span of the movement and two others operating to generate movement, one aligned with the vertical and the other aligned with the horizontal. PMID:25620928

Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana Maria; Dan, Bernard; Cheron, Guy; McIntyre, Joseph

2014-01-01

73

Neurobehavioral toxicology of pyrethroid insecticides  

SciTech Connect

Pyrethroid insecticides are classified as either Type I or Type II based upon in vivo toxic signs, and neurophysiological and biochemical data. Both axonal sodium channels and the ..gamma..-aminobutyric acid (GABA) receptor complex have been proposed as the major site of action of the Type II pyrethroids. This investigation characterized the behavior and biochemical effects of low dosages of pyrethroids in rats. Type I and II pyrethroids were tested for effects on figure-eight maze activity and the acoustic startle response (ASR). All compounds decreased figure-eight maze activity. Interactions of Type I and II pyrethroids with the three major binding sites on the GABA complex were determined in vivo. Radioligand binding experiments assessed in vitro interactions of pyrethroids with the three major GABA-complex binding sites. None of the pyrethroids competed for (/sup 3/H)-muscimol or (/sup 3/H)-flunitrazepam binding. Only Type II pyrethroids inhibited binding of (/sup 35/S)-t-butylbicyclophosphorothionate (TBPS) in cortical synaptosome preparations with K/sub i/ values of 5 to 10 ..mu..M. The (/sup 35/S)-TBPS data implicate the TBPS/picrotoxinin binding site in the mechanism of Type II pyrethroid toxicity. The results of these experiments support the classification of pyrethroids into two classes, and demonstrate the utility of the figure-eight maze and the ASR in studies to elucidate neurotoxic mechanisms. The interaction of the Type II pyrethroids is probably restricted to the TBPS/picrotoxinin binding domain on the GABA complex as shown by both the in vivo and in vitro studies.

Crofton, K.M.

1986-01-01

74

A general method for deriving vector potentials produced by knotted solenoids  

NASA Astrophysics Data System (ADS)

A general method for deriving exact expressions for vector potentials produced by arbitrarily knotted solenoids is presented. It consists of using simple physics ideas from magnetostatics to evaluate the magnetic field in a surrogate problem. The latter is obtained by modeling the knot with wire segments carrying steady currents on a cubical lattice. The expressions for a 31 (trefoil) and a 41 (figure-eight) knot are explicitly worked out. The results are of some importance in the study of the Aharonov-Bohm effect generalized to a situation in which charged particles moving through force-free regions are scattered by fluxes confined to the interior of knotted impenetrable tubes.

Sreedhar, V. V.

2014-10-01

75

Continuation of periodic orbits in symmetric Hamiltonian and conservative systems  

NASA Astrophysics Data System (ADS)

We present and review results on the continuation and bifurcation of periodic solutions in conservative, reversible and Hamiltonian systems in the presence of symmetries. In particular we show how two-point boundary value problem continuation software can be used to compute families of periodic solutions of symmetric Hamiltonian systems. The technique is introduced with a very simple model example (the mathematical pendulum), justified with a theoretical continuation result and then applied to two non trivial examples: the non integrable spring pendulum and the continuation of the figure eight solution of the three body problem.

Galan-Vioque, J.; Almaraz, F. J. M.; Macías, E. F.

2014-12-01

76

Design Optimization for a Maglev System Employing Flux Eliminating Coils  

NASA Technical Reports Server (NTRS)

Flux eliminating coils have received no little attention over the past thirty years as an alternative for realizing lift in a MAGLEV system. When the magnets on board the vehicle are displaced from the equilibrium or null flux point of these coils, they induce current in those coils which act to restore the coil to its null flux or centerline position. The question being addressed in this paper is that of how to choose the best coil for a given system. What appears at first glance to be an innocent question is in fact one that is actually quite involved, encompassing both the global economics and physics of the system. The real key in analyzing that question is to derive an optimization index or functional which represents the cost of the system subject to constraints, the primary constraint being that the vehicle lift itself at a certain threshold speed. Outlined in this paper is one scenario for realizing a total system design which uses sequential quadratic programming techniques.

Davey, Kent R.

1996-01-01

77

Numerical investigation on flow-induced vibration of a triangular cylinder at a low Reynolds number  

NASA Astrophysics Data System (ADS)

Flow-induced vibration (FIV) of a triangular cylinder is numerically investigated at a Reynolds number of Re = 100. The four-step fractional finite element method is employed to solve the two-dimensional (2D) incompressible Navier–Stokes equations. The cylinder is endowed with a two-degree-of-freedom motion with the reduced mass ratio of Mr = 2. Three typical flow incidence angles, ? = 0°, 30° and 60°, are examined to identify the effect of incidence angle on the vibration characteristics of the cylinder. For each ?, computations are conducted in a wide range of reduced velocities 2 Ur ? 18. The numerical results show that at ? = 0° and 30°, the responses of the cylinder are dominated by vortex-induced vibration which resembles that of a circular cylinder. At ? = 0°, the peak amplitude of transverse vibration is the smallest among the three investigated ?, and most of the cylinder motions exhibit a regular figure-eight trajectory. Some single-loop trajectories are observed at ? = 30°, where the vibration frequency in the in-line direction is always identical to that in the transverse direction. At ? = 60°, the triangular cylinder undergoes a typical transverse galloping with large amplitude and low frequency, and the vibration trajectories appear to be regular or irregular figure-eight patterns, which are strongly affected by the reduced velocity.

Wang, Huakun; Zhao, Dongliang; Yang, Wenyu; Yu, Guoliang

2015-02-01

78

Path Integration: Effect of Curved Path Complexity and Sensory System on Blindfolded Walking  

PubMed Central

Path integration refers to the ability to integrate continuous information of the direction and distance travelled by the system relative to the origin. Previous studies have investigated path integration through blindfolded walking along simple paths such as straight line and triangles. However, limited knowledge exists regarding the role of path complexity in path integration. Moreover, little is known about how information from different sensory input systems (like vision and proprioception) contributes to accurate path integration. The purpose of the current study was to investigate how sensory information and curved path complexity affect path integration. Forty blindfolded participants had to accurately reproduce a curved path and return to the origin. They were divided into four groups that differed in the curved path, circle (simple) or figure-eight (complex), and received either visual (previously seen) or proprioceptive (previously guided) information about the path before they reproduced it. The dependent variables used were average trajectory error, walking speed, and distance travelled. The results indicated that (a) both groups that walked on a circular path and both groups that received visual information produced greater accuracy in reproducing the path. Moreover, the performance of the group that received proprioceptive information and later walked on a figure-eight path was less accurate than their corresponding circular group. The groups that had the visual information also walked faster compared to the group that had proprioceptive information. Results of the current study highlight the roles of different sensory inputs while performing blindfolded walking for path integration. PMID:22840893

Koutakis, Panagiotis; Mukherjee, Mukul; Vallabhajosula, Srikant; Blanke, Daniel J.; Stergiou, Nicholas

2012-01-01

79

Degradation model for erbium-doped fiber amplifiers to reduce network downtime  

E-print Network

Degradation model for erbium-doped fiber amplifiers to reduce network downtime Christian Merkle optical amplifiers and cross connects reduces the availability of a network and increases the operational of erbium-doped amplifiers (EDFAs) can be used to reduce the repair time by changing an EDFA before it fails

Paris-Sud XI, Université de

80

LAND USE AND SEASONAL EFFECTS ON URBAN STORMWATER RUNOFF MICROORGANISM CONCENTRATIONS  

EPA Science Inventory

Stormwater samples collected from storm sewers draining small municipal separate storm sewer systems shown to be free of cross connections within an urban watershed dominated by a single land use were analyzed for pathogens (Pseudomonas aeruginosa and Staphylococcus aureus) and i...

81

Performance management issues of currently operated ATM enterprise networks  

Microsoft Academic Search

The author proposes a solution for the allocation and balancing of resources to maximize available bandwidth shared among corporate users. Currently established broadband virtual private networks (BVPNs) based on asynchronous transfer mode (ATM) technology comprise ATM cross-connects (ATM-CCs) and a lot of intelligent customer premises equipment (CPE). The CPE, an intelligent ATM service switcher or ATM multiplexer, enables the corporate

Rudolf Jaeger

1996-01-01

82

PXC protection switching triggered by performance monitoring with FEC for submarine cable networks  

Microsoft Academic Search

We have successfully demonstrated the protection-switching operation of photonic cross connect (PXC) triggered by the performance degradation threshold of the bit error ratio monitored with FEC in S-LTE for optical submarine cable networks. We confirmed that once the monitored errors exceed the threshold of the submarine line terminal equipment this immediately generates the loss of signal to initiate PXCs to

T. Otani; M. Hayashi; S. Yamamoto; M. Suzuki; N. Toda; K. Raychaudhuri

2002-01-01

83

James Clerk Maxwell Prize for Plasma Physics: The Physics of Magnetic Reconnection and Associated Particle Acceleration  

Microsoft Academic Search

Solar and stellar flares, substorms in the Earth's magnetosphere, and disruptions in laboratory fusion experiments are driven by the explosive release of magnetic energy through the process of magnetic reconnection. During reconnection oppositely directed magnetic fields break and cross-connect. The resulting magnetic slingshots convert magnetic energy into high velocity flows, thermal energy and energetic particles. A major scientific challenge has

James Drake

2010-01-01

84

An in-depth cross-layer experimental study of transport protocols over circuits  

E-print Network

mismatched-rate circuits. Such circuits are created when a high-speed port, such as a GigE (Gb/s Ethernet switches; instead they are hybrid nodes that include Ethernet interfaces that allow for the connection of host Ethernet NICs. While as with ordinary circuit switches, cross-connections have to be provisioned

Veeraraghavan, Malathi

85

75 FR 8769 - Self-Regulatory Organizations; BATS Exchange, Inc.; Order Approving Proposed Rule Change, as...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Exchange at the data centers where the Exchange's servers are located (i.e., either a cross-connection or a private line Ethernet connection to the Exchange's network within the data center). \\7\\ The Commission notes that BATS will implement the...

2010-02-25

86

77 FR 48576 - Self-Regulatory Organizations; BATS Exchange, Inc.; Notice of Filing and Immediate Effectiveness...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Exchange at the data centers where the Exchange's servers are located (i.e., either a cross-connection or a private line Ethernet connection to the Exchange's network within the data center). Multiple logical ports can be created for a single...

2012-08-14

87

75 FR 1109 - Self-Regulatory Organizations; BATS Exchange, Inc.; Notice of Filing of Proposed Rule Change To...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Exchange at the data centers where the Exchange's servers are located (i.e., either a cross-connection or a private line Ethernet connection to the Exchange's network within the data center). Multiple logical ports can be created for a single...

2010-01-08

88

Evolution, Jung, and Theurgy: Their Role in Modern Neoplatonism  

E-print Network

-1- Evolution, Jung, and Theurgy: Their Role in Modern Neoplatonism Extended Version1 Bruce Mac. Introduction This paper explores the rich cross-connections between Neoplatonism, Jungian psychology and evolutionary neuroethology can bring to Neoplatonism; in particular, I will use them to explicate theurgical

MacLennan, Bruce

89

The Advent of WDM and the All-Optical Network: A Reality Check.  

ERIC Educational Resources Information Center

Discussion of the telecommunications industry focuses on WDM (wavelength division multiplexing) as a solution for dealing with capacity constraints. Highlights include fiber optic technology; cross-connecting and switching wavelengths; SONET (Synchronous Optical Network) and wavelength networking; and optical TDM (Time Division Multiplexing). (LRW)

Lutkowitz, Mark

1998-01-01

90

Temperature Compensated Air/Fuel Ratio Control on a Recuperated Furnace  

E-print Network

When recuperation is added to a furnace, air/ fuel ratio control seemingly becomes more complicated. Two methods normally used are mass flow control where the fuel pressure or flow is proportional to the mass flow of air or cross-connected control...

Ferri, J. L.

1983-01-01

91

Performance Comparison of Agile Optical Network Architectures with Static Vs. Dynamic Regenerator  

E-print Network

Performance Comparison of Agile Optical Network Architectures with Static Vs. Dynamic Regenerator, david.griffith, borchert, golmie}@nist.gov Abstract-- Agile all optical cross-connect (OXC) switches cur consisting of 53 nodes. The simulation study was carried out using NIST's updated GMPLS Lightwave Agile

92

Waterworks Operator Training Manual.  

ERIC Educational Resources Information Center

Sixteen self-study waterworks operators training modules are provided. Module titles are the following: basic mathematics, basic chemistry, analysis procedures, microbiology, basic electricity, hydraulics, chlorination, plant operation, surface water, ground water, pumps, cross connections, distribution systems, safety, public relations, and…

Missouri Univ., Columbia. Instructional Materials Lab.

93

46 CFR 154.1125 - Pipes, fittings, and valves.  

Code of Federal Regulations, 2014 CFR

...fitting, and valve for each water spray system must meet Part 56 of this chapter. (b) Each water spray main that protects more than...cross-connection from the water spray system to the fire main must be outside of the...

2014-10-01

94

46 CFR 154.1125 - Pipes, fittings, and valves.  

Code of Federal Regulations, 2013 CFR

...fitting, and valve for each water spray system must meet Part 56 of this chapter. (b) Each water spray main that protects more than...cross-connection from the water spray system to the fire main must be outside of the...

2013-10-01

95

Electroholography 2001 Electroholographic Wavelength Selective Switches in  

E-print Network

of the communications technologies. In particular, in optical fiber communication systems, which are the dominant technologies including microelectronic machining, liquid crystals, integrated optic, and piezoelectric mirrors dynamic optical add drop multiplexer. 5.2. The Electroholographic cross connect. 6. Conclusions. #12

Agranat, Aharon J.

96

112 Home Power #72 August / September 1999 Code Corner  

E-print Network

protection. The utilities always rely on extensive electronic ground-fault detectors in their ungrounded DC, and to prevent excessive voltages due to surges from lightning or unintentional cross connections with higher they are prone to picking up induced surges from nearby lightning strikes. Utility-interactive inverters are also

Johnson, Eric E.

97

Abstract --Core optical networks can benefit from lower costs and increased speed by reducing O-E-O conversions through use of  

E-print Network

Abstract -- Core optical networks can benefit from lower costs and increased speed by reducing O-E-O conversions through use of ultra long reach optical transport, and bit-rate and wavelength transparent cross-connects. While pure optical transparency avoids the high cost of deploying optical termination units (OTUs

Mitra, Debasis

98

Oktober 2000 OPTICAL NETWORKS MAGAZINE 1 GALEN H. SASAKI  

E-print Network

acceptance for applications where fiber is precious, such as in long-haul transport or fiber-scarce metro low ADM costs. It is shown that networks that allow traffic to be cross-connected have lower ADM costs traffic onto the optical lines using time division multiplexing (TDM). SONET ADMs are a major cost item

Sasaki, Galen H.

99

Analysis of an electrodynamic maglev system  

SciTech Connect

Electrodynamic systems (EDS's) for maglev have an advantage over electromagnetic systems (EMS's) in that the stability is built into the system. EDS's induce the currents used for levitation and guidance, while EMS's impose those currents with controlled feedback. The movement of a magnet over properly designed EDS coils results in forces to keep the system fixed in the lowest energy or null flux spot. In the past such systems have been examined through two-dimensional boundary element techniques. An approximation to the full three-dimensional time harmonic problem is obtained through LaPlace transform theory after using boundary element methods to predict the mutual coupling of the magnets with the track coils. The analytic solution offers helpful design and operation guidelines.

Davey, K.

1999-09-01

100

Gyration radius of a circular polymer under a topological constraint with excluded volume  

E-print Network

It is nontrivial whether the average size of a ring polymer should become smaller or larger under a topological constraint. Making use of some knot invariants, we evaluate numerically the mean square radius of gyration for ring polymers having a fixed knot type, where the ring polymers are given by self-avoiding polygons consisting of freely-jointed hard cylinders. We obtain plots of the gyration radius versus the number of polygonal nodes for the trivial, trefoil and figure-eight knots. We discuss possible asymptotic behaviors of the gyration radius under the topological constraint. In the asymptotic limit, the size of a ring polymer with a given knot is larger than that of no topological constraint when the polymer is thin, and the effective expansion becomes weak when the polymer is thick enough.

Miyuki K. Shimamura; Tetsuo Deguchi

2001-04-02

101

Topological effects in the thermal properties of knotted polymer rings  

E-print Network

The topological effects on the thermal properties of several knot configurations are investigated using Monte Carlo simulations. In order to check if the topology of the knots is preserved during the thermal fluctuations we propose a method that allows very fast calculations and can be easily applied to arbitrarily complex knots. As an application, the specific energy and heat capacity of the trefoil, the figure-eight and the $8_1$ knots are calculated at different temperatures and for different lengths. Short-range repulsive interactions between the monomers are assumed. The knots configurations are generated on a three-dimensional cubic lattice and sampled by means of the Wang-Landau algorithm and of the pivot method. The obtained results show that the topological effects play a key role for short-length polymers. Three temperature regimes of the growth rate of the internal energy of the system are distinguished.

Yani Zhao; Franco Ferrari

2012-09-08

102

The reversal and chaotic attractor in the nonholonomic model of Chaplygin's top  

NASA Astrophysics Data System (ADS)

In this paper we consider the motion of a dynamically asymmetric unbalanced ball on a plane in a gravitational field. The point of contact of the ball with the plane is subject to a nonholonomic constraint which forbids slipping. The motion of the ball is governed by the nonholonomic reversible system of 6 differential equations. In the case of arbitrary displacement of the center of mass of the ball the system under consideration is a nonintegrable system without an invariant measure. Using qualitative and quantitative analysis we show that the unbalanced ball exhibits reversal (the phenomenon of reversal of the direction of rotation) for some parameter values. Moreover, by constructing charts of Lyaponov exponents we find a few types of strange attractors in the system, including the so-called figure-eight attractor which belongs to the genuine strange attractors of pseudohyperbolic type.

Borisov, Alexey V.; Kazakov, Alexey O.; Sataev, Igor R.

2014-11-01

103

The Penguin: a Low Reynolds Number Powered Glider for Station Keeping Missions  

NASA Technical Reports Server (NTRS)

The Penguin is a low Reynolds number (approx. 100,000) remotely piloted vehicle (RPV). It was designed to fly three laps indoors around two pylons in a figure-eight course while maximizing loiter time. The Penguin's low Reynolds number mission is an important one currently being studied for possible future flights in the atmospheres of other planets and for specialized military missions. Although the Penguin's mission seemed quite simple at first, the challenges of such low Reynolds number flight have proven to be quite unique. In addition to the constraint of low Reynolds number flight, the aircraft had to be robust in its control, highly durable, and it had to carry a small instrument package. The Penguin's flight plan, concept, performance, aerodynamic design, weight estimation, structural design, propulsion, stability and control, and cost estimate is detailed.

Costello, J. K.; Greene, D. W.; Lee, T. T.; Matier, P. T.; Mccarthy, T. R.; Mcguire, R. J.; Schuette, M. J.

1990-01-01

104

Magnetic Resonance Imaging of time-varying magnetic fields from therapeutic devices  

PubMed Central

While magnetic resonance imaging of static magnetic fields generated by external probes has been previously demonstrated, there is an unmet need to image time-varying magnetic fields, such as those generated by transcranial magnetic stimulators or radiofrequency hyperthermia probes. A method to image such time-varying magnetic fields is introduced in this work. This article presents the theory behind the method and provides proof of concept by imaging time-varying magnetic fields generated by a figure-eight coil inside simple phantoms over a range of frequencies and intensities, using a 7T small animal MRI scanner. The method is able to reconstruct the three-dimensional components of the oscillating magnetic field vector. PMID:23355446

Hernandez-Garcia, Luis; Bhatia, Vivek; Prem-Kumar, Krishan; Ulfarsson, Magnus

2013-01-01

105

Control protocol and its performance analysis for distributed ATM virtual path self-healing network  

Microsoft Academic Search

A restorable network comprised of a mesh of ATM virtual paths (AVPs) is expected to be superior to distributed SONET digital cross-connect self-healing networks in terms of restoration time. The paper presents a reliable protocol and evaluation of its performance for control information transfer in distributed AVP self-healing networks. Two error-recovery technologies for the data-link level (selective retransmission and go-back-N)

Noriaki Yoshikai; Tsong-Ho Wu

1994-01-01

106

Design and Performance of Novel Optical Fiber Distribution and Management System With Testing Functions in Central Office  

Microsoft Academic Search

This paper describes the design and performance of a novel central office optical fiber distribution and management system for opticalaccess networks.Weclarifythe requirements for an opticalfiber distribution and management system with a testing function. We propose integrated distribution modules (IDMs) and high-count indoor cables for high-capacity cable termination and cross connection, a management system using identification tags for easy administration and

Yoshitaka Enomoto; Hisashi Izumita; Koji Mine; Shigenori Uruno; Nobuo Tomita

2011-01-01

107

1296-port MEMS transparent optical crossconnect with 2.07 petabit\\/s switch capacity  

Microsoft Academic Search

A 1296-port MEMS transparent optical crossconnect with 5.1dB±1.1dB insertion loss at 1550 nm is reported. Measured worst-case optical crosstalk in a fabric was n38 dB and nominal switching rise\\/fall times were 5 ms. A 2.07 petabit\\/s switch capacity was verified upon cross-connecting a forty-channel by 40 Gb\\/s DWDM data stream through a prototype fabric.

R. Ryf; J. Kim; J. P. Hickey; A. Gnauck; D. Carr; F. Pardo; C. Bolle; R. Frahm; N. Basavanhally; C. Yoh; D. Ramsey; R. Boie; R. George; J. Kraus; C. Lichtenwalner; R. Papazian; J. Gates; H. R. Shea; A. Gasparyan; V. Muratov; J. E. Griffith; J. A. Prybyla; S. Goyal; C. D. White; M. T. Lin; R. Ruel; C. Nijander; S. Arney; D. T. Neilson; D. J. Bishop; P. Kolodner; S. Pau; C. Nuzman; A. Weis; B. Kumar; D. Lieuwen; V. Aksyuk; D. S. Greywall; T. C. Lee; H. T. Soh; W. M. Mansfield; S. Jin; W. Y. Lai; H. A. Huggins; D. L. Barr; R. A. Cirelli; G. R. Bogart; K. Teffeau; R. Vella; H. Mavoori; A. Ramirez; N. A. Ciampa; F. P. Klemens; M. D. Morris; T. Boone; J. Q. Liu; J. M. Rosamilia; C. R. Giles

2001-01-01

108

ATM transport system architecture and field trial  

Microsoft Academic Search

The ATM link system will play an important role in constructing virtual path transport networks for the future B-ISDN. A prototype ATM link system is implemented that exhibits the benefits of ATM to the greatest possible extent. This system features not only very high-speed line interfaces, large capacity cross-connect networks, and built-in functions that contribute to efficient operation and maintenance,

Ikuo Tokizawa; Hiromi Ueda; K. Kiskuchi

1993-01-01

109

Cycle-oriented distributed preconfiguration: ring-like speed with mesh-like capacity for self-planning network restoration  

Microsoft Academic Search

Cycle-oriented preconfiguration of spare capacity is a new idea for the design and operation of mesh-restorable networks. It offers a sought-after goal: to retain the capacity-efficiency of a mesh-restorable network, while approaching the speed of line-switched self-healing rings. We show that through a strategy of pre-failure cross-connection between the spare links of a mesh network, it is possible to achieve

Wayne D. Grover; Demetrios Stamatelakis

1998-01-01

110

Survivable WDM Mesh Networks  

Microsoft Academic Search

Abstract, In a wavelength-division-muliplexing (WDM) optical network, the failure of network elements (e. g., fiber links and cross connects) may cause the failure of several optical channels, thereby leading to large data losses. This study examines different approaches to protect a mesh-based WDM optical network from such failures. These approaches are based on two survivability paradigms: 1) path protection\\/restoration and

S. Ramamurthy; Laxman Sahasrabuddhe; Biswanath Mukherjee

2003-01-01

111

Digital-data receiver synchronization method and apparatus  

DOEpatents

Digital data receiver synchronization is provided with composite phase-frequency detectors, mutually cross-connected comparison feedback or both to provide robust reception of digital data signals. A single master clock can be used to provide frequency signals. Advantages can include fast lock-up time in moderately to severely noisy conditions, greater tolerance to noise and jitter when locked, and improved tolerance to clock asymmetries.

Smith, Stephen F. (Loudon, TN) [Loudon, TN; Turner, Gary W. (Clinton, TN) [Clinton, TN

2009-09-08

112

Comparative human health risk analysis of coastal community water and waste service options.  

PubMed

As a pilot approach to describe adverse human health effects from alternative decentralized community water systems compared to conventional centralized services (business-as-usual [BAU]), selected chemical and microbial hazards were assessed using disability adjusted life years (DALYs) as the common metric. The alternatives included: (1) composting toilets with septic system, (2) urine-diverting toilets with septic system, (3) low flush toilets with blackwater pressure sewer and on-site greywater collection and treatment for nonpotable reuse, and (4) alternative 3 with on-site rainwater treatment and use. Various pathogens (viral, bacterial, and protozoan) and chemicals (disinfection byproducts [DBPs]) were used as reference hazards. The exposure pathways for BAU included accidental ingestion of contaminated recreational water, ingestion of cross-connected sewage to drinking water, and shower exposures to DBPs. The alternative systems included ingestion of treated greywater from garden irrigation, toilet flushing, and crop consumption; and ingestion of treated rainwater while showering. The pathways with the highest health impact included the ingestion of cross-connected drinking water and ingestion of recreational water contaminated by septic seepage. These were also among the most uncertain when characterizing input parameters, particularly the scale of the cross-connection event, and the removal of pathogens during groundwater transport of septic seepage. A comparison of the health burdens indicated potential health benefits by switching from BAU to decentralized water and wastewater systems. PMID:24988142

Schoen, Mary E; Xue, Xiaobo; Hawkins, Troy R; Ashbolt, Nicholas J

2014-08-19

113

Novel cryogen-free actively shielded superconducting magnets for maglev vehicles. Final report, August 1991-June 1992  

SciTech Connect

The report presents the results of a research effort into the design of a shielded superconducting magnet system for a maglev vehicle. The magnet design is based on a novel cryogen-free technology which allows operation without the use of any cryogenic fluids. This is accomplished by the use of a two-stage Gifford-McMahon (G-M) cryogenic refrigerator to provide cooling of the coil and a single cryostat thermal radiation shield by conduction. The design operating temperature of the magnet is 7.5 K, and that of the shield is 43 K. The magnet is wound with a tape form of niobium tin superconductor which allows operation at a module current density of 8100 A/sq cm at a flux density of 3.4 T at the 7.5 K temperature with a margin of 4.5 K to critical temperature. The magnet design is coupled with a linear synchronous motor and null-flux sidewall levitation system to provide a workable maglev system design. Costs for several components of the design, including coils and cryostat, shielding, and power conditioning apparatus are estimated.

Vermilyea, M.E.

1992-06-01

114

Spatial Light Modulators as Optical Crossbar Switches  

NASA Technical Reports Server (NTRS)

A proposed method of implementing cross connections in an optical communication network is based on the use of a spatial light modulator (SLM) to form controlled diffraction patterns that connect inputs (light sources) and outputs (light sinks). Sources would typically include optical fibers and/or light-emitting diodes; sinks would typically include optical fibers and/or photodetectors. The sources and/or sinks could be distributed in two dimensions; that is, on planes. Alternatively or in addition, sources and/or sinks could be distributed in three dimensions -- for example, on curved surfaces or in more complex (including random) three-dimensional patterns.

Juday, Richard

2003-01-01

115

DWDM switching with network photonics CrossWave technology: the third-generation optical switching technology  

NASA Astrophysics Data System (ADS)

CrossWave$TM) multiplexed domain switches enable low cost, simple, reliable and scalable architectures for a wide variety of wavelength selective cross connects, dynamically reconfigurable add/drop multiplexers and hybrid optical core switches. As DWDM becomes ubiquitous in long haul and metro core networks, carriers are looking to optical switching to manage the ever-growing number of wavelengths and to automate wavelength routing, restoration and grooming. To meet these requirements, optical core switches (OCSs) need to scale to accommodate high wavelength counts, high TDM bit rates and various types of transport protocols such as SONET and GbE.

Georgis, Steven

2001-10-01

116

Bulk mixed ion electron conduction in amorphous gallium oxide causes memristive behaviour.  

PubMed

In thin films of mixed ionic electronic conductors sandwiched by two ion-blocking electrodes, the homogeneous migration of ions and their polarization will modify the electronic carrier distribution across the conductor, thereby enabling homogeneous resistive switching. Here we report non-filamentary memristive switching based on the bulk oxide ion conductivity of amorphous GaOx (x~1.1) thin films. We directly observe reversible enrichment and depletion of oxygen ions at the blocking electrodes responding to the bias polarity by using photoemission and transmission electron microscopies, thus proving that oxygen ion mobility at room temperature causes memristive behaviour. The shape of the hysteresis I-V curves is tunable by the bias history, ranging from narrow counter figure-eight loops to wide hysteresis, triangle loops as found in the mathematically derived memristor model. This dynamical behaviour can be attributed to the coupled ion drift and diffusion motion and the oxygen concentration profile acting as a state function of the memristor. PMID:24632885

Aoki, Yoshitaka; Wiemann, Carsten; Feyer, Vitaliy; Kim, Hong-Seok; Schneider, Claus Michael; Ill-Yoo, Han; Martin, Manfred

2014-01-01

117

Bulk mixed ion electron conduction in amorphous gallium oxide causes memristive behaviour  

NASA Astrophysics Data System (ADS)

In thin films of mixed ionic electronic conductors sandwiched by two ion-blocking electrodes, the homogeneous migration of ions and their polarization will modify the electronic carrier distribution across the conductor, thereby enabling homogeneous resistive switching. Here we report non-filamentary memristive switching based on the bulk oxide ion conductivity of amorphous GaOx (x~1.1) thin films. We directly observe reversible enrichment and depletion of oxygen ions at the blocking electrodes responding to the bias polarity by using photoemission and transmission electron microscopies, thus proving that oxygen ion mobility at room temperature causes memristive behaviour. The shape of the hysteresis I-V curves is tunable by the bias history, ranging from narrow counter figure-eight loops to wide hysteresis, triangle loops as found in the mathematically derived memristor model. This dynamical behaviour can be attributed to the coupled ion drift and diffusion motion and the oxygen concentration profile acting as a state function of the memristor.

Aoki, Yoshitaka; Wiemann, Carsten; Feyer, Vitaliy; Kim, Hong-Seok; Schneider, Claus Michael; Ill-Yoo, Han; Martin, Manfred

2014-03-01

118

Imaging the early stages of phospholipase C/sphingomyelinase activity on vesicles containing coexisting ordered-disordered and gel-fluid domains[S  

PubMed Central

The binding and early stages of activity of a phospholipase C/sphingomyelinase from Pseudomonas aeruginosa on giant unilamellar vesicles (GUV) have been monitored using fluorescence confocal microscopy. Both the lipids and the enzyme were labeled with specific fluorescent markers. GUV consisted of a mixture of phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, and cholesterol in equimolar ratios, to which 5–10 mol% of the enzyme end-product ceramide and/or diacylglycerol were occasionally added. Morphological examination of the GUV in the presence of enzyme reveals that, although the enzyme diffuses rapidly throughout the observation chamber, detectable enzyme binding appears to be a slow, random process, with new bound-enzyme-containing vesicles appearing for several minutes. Enzyme binding to the vesicles appears to be a cooperative process. After the initial cluster of bound enzyme is detected, further binding and catalytic activity follow rapidly. After the activity has started, the enzyme is not released by repeated washing, suggesting a “scooting” mechanism for the hydrolytic activity. The enzyme preferentially binds the more disordered domains, and, in most cases, the catalytic activity causes the disordering of the other domains. Simultaneously, peanut- or figure-eight-shaped vesicles containing two separate lipid domains become spherical. At a further stage of lipid hydrolysis, lipid aggregates are formed and vesicles disintegrate. PMID:21252263

Ibarguren, Maitane; López, David J.; Montes, L.-Ruth; Sot, Jesús; Vasil, Adriana I.; Vasil, Michael L.; Goñi, Félix M.; Alonso, Alicia

2011-01-01

119

Two-dimensional spatially selective spin inversion and spin-echo refocusing with a single nuclear magnetic resonance pulse  

NASA Astrophysics Data System (ADS)

A new class of nuclear magnetic resonance (NMR) pulses that provides simultaneous spatially selective inversion of nuclear spins in two dimensions following a single pulse application is described and demonstrated. The two-dimensional selective pulses consist of a single square- or amplitude-modulated ? rf pulse applied in the presence of an amplitude-modulated magnetic field gradient that reorients through the two dimensions during the rf pulse. For example, square and Gaussian rf pulses produce sharply peaked sombrero-, egg-carton-, and stalagmite-shaped profiles of spin inversion in the xz plane when applied in the presence of a gradient that rotates or describes a figure eight in the xz plane. The theoretical profiles, computed by numerical integration of the Bloch equation, are in good agreement with experimental results obtained by incorporating the pulses into a conventional NMR imaging sequence. The pulses are directly applicable to restricted field-of-view high-resolution imaging for the amelioration of aliasing signal artifacts, and when combined with one-dimensional localized phosphorus (31P) chemical shift spectroscopy techniques that employ surface detection coils, should permit complete three-dimensionally localized 31P NMR spectroscopy. The ? pulses provide similar two-dimensional spatial selectivity of the transverse nuclear magnetization when used for refocusing Hahn spin echoes.

Bottomley, Paul A.; Hardy, Christopher J.

1987-11-01

120

Compensation Techniques in Accelerator Physics  

SciTech Connect

Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain, and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Two problems involving compensation are studied in the context of the MEIC (Medium Energy Electron Ion Collider) project at Jefferson Laboratory. Several chromaticity (the energy dependence of the particle tune) compensation methods are evaluated numerically and deployed in a figure eight ring designed for the electrons in the collider. Furthermore, transverse coupling optics have been developed to compensate the coupling introduced by the spin rotators in the MEIC electron ring design.

Hisham Kamal Sayed

2011-05-31

121

Three-body choreographies in given curves  

NASA Astrophysics Data System (ADS)

As shown by Johannes Kepler in 1609, in the two-body problem, the shape of the orbit, a given ellipse, and a given non-vanishing constant angular momentum determine the motion of the planet completely. Even in the three-body problem, in some cases, the shape of the orbit, conservation of the center of mass and a constant of motion (the angular momentum or the total energy) determine the motion of the three bodies. We show, by a geometrical method, that choreographic motions, in which equal mass three bodies chase each other around the same curve, will be uniquely determined for the following two cases. (i) Convex curves that have point symmetry and non-vanishing angular momentum are given. (ii) Eight-shaped curves which are similar to the curve for the figure-eight solution and the energy constant are given. The reality of the motion should be tested whether the motion satisfies an equation of motion or not. Extensions of the method for generic curves are shown. The extended methods are applicable to generic curves which do not have point symmetry. Each body may have its own curve and its own non-vanishing masses.

Ozaki, Hiroshi; Fukuda, Hiroshi; Fujiwara, Toshiaki

2009-10-01

122

Spatiotemporal topology and temporal sequence identification with an adaptive time-delay neural network  

NASA Astrophysics Data System (ADS)

Inspired from the time delays that occur in neurobiological signal transmission, we describe an adaptive time delay neural network (ATNN) which is a powerful dynamic learning technique for spatiotemporal pattern transformation and temporal sequence identification. The dynamic properties of this network are formulated through the adaptation of time-delays and synapse weights, which are adjusted on-line based on gradient descent rules according to the evolution of observed inputs and outputs. We have applied the ATNN to examples that possess spatiotemporal complexity, with temporal sequences that are completed by the network. The ATNN is able to be applied to pattern completion. Simulation results show that the ATNN learns the topology of a circular and figure eight trajectories within 500 on-line training iterations, and reproduces the trajectory dynamically with very high accuracy. The ATNN was also trained to model the Fourier series expansion of the sum of different odd harmonics. The resulting network provides more flexibility and efficiency than the TDNN and allows the network to seek optimal values for time-delays as well as optimal synapse weights.

Lin, Daw-Tung; Ligomenides, Panos A.; Dayhoff, Judith E.

1993-08-01

123

Vortex-induced vibrations of a flexible cylinder at large inclination angle.  

PubMed

The free vibrations of a flexible circular cylinder inclined at 80° within a uniform current are investigated by means of direct numerical simulation, at Reynolds number 500 based on the body diameter and inflow velocity. In spite of the large inclination angle, the cylinder exhibits regular in-line and cross-flow vibrations excited by the flow through the lock-in mechanism, i.e. synchronization of body motion and vortex formation. A profound reconfiguration of the wake is observed compared with the stationary body case. The vortex-induced vibrations are found to occur under parallel, but also oblique vortex shedding where the spanwise wavenumbers of the wake and structural response coincide. The shedding angle and frequency increase with the spanwise wavenumber. The cylinder vibrations and fluid forces present a persistent spanwise asymmetry which relates to the asymmetry of the local current relative to the body axis, owing to its in-line bending. In particular, the asymmetrical trend of flow-body energy transfer results in a monotonic orientation of the structural waves. Clockwise and counter-clockwise figure eight orbits of the body alternate along the span, but the latter are found to be more favourable to structure excitation. Additional simulations at normal incidence highlight a dramatic deviation from the independence principle, which states that the system behaviour is essentially driven by the normal component of the inflow velocity. PMID:25512586

Bourguet, Rémi; Triantafyllou, Michael S

2015-01-28

124

Ni(II) Metalations of [40]- and [42]Nonaphyrins(1.1.1.1.1.1.1.1.1): The Largest Doubly Twisted Hückel Antiaromatic Molecule.  

PubMed

Ni(II) metalation of [42]nonaphyrin gave two Hückel aromatic [42]nonaphyrin Ni(II) complexes that possess different doubly twisted figure-eight conformations. While these complexes are conformers, the activation barriers for conformational interconversion were found to be exceptionally high. However, one-way isomerization from the higher-energy conformer to the lower-energy conformer can be induced upon treatment with trifluoroacetic acid (TFA). This conformational isomerization has been suggested to proceed via a protonation-induced caterpillar-like conformational rotation of the metal-free hexaphyrin-like segment by examining the similar isomerization of an A3 B6 -type [42]nonaphyrin Ni(II) complex. Rh(I) metalation of the lower-energy [42]nonaphyrin Ni(II) complex afforded a [42]nonaphyrin Ni(II) -Rh(I) hybrid complex, which was oxidized with p-chloranil to produce a [40]nonaphyrin Ni(II) -Rh(I) hybrid complex as the largest doubly twisted Hückel antiaromatic molecule to date. PMID:25250529

Soya, Takanori; Naoda, Koji; Osuka, Atsuhiro

2015-01-01

125

Optimization of multiple coils immersed in a conducting liquid for half-hemisphere or whole-brain deep transcranial magnetic stimulation: A simulation study.  

PubMed

Transcranial magnetic stimulation (TMS) was proposed in 1985. Nevertheless, its wider use in the treatment of several neurologic diseases has been hindered by its inability to stimulate deep-brain regions. This is mainly due to the physical limiting effect arising from the presence of surface discontinuities, particularly between the scalp and air. Here, we present the optimization of a system of large multiple coils for whole-brain and half-hemisphere deep TMS, termed orthogonal configuration. COMSOL(®)-based simulations show that the system is capable of reaching the very center of a spherical brain phantom with 58% induction relative to surface maximum. Such penetration capability surpasses to the best of our knowledge that of existing state of the art TMS systems. This induction capability strongly relies on the immersion of the stimulating coils and part of the head of the patient in a conducting liquid (e.g. simple saline solution). We show the impact of the presence of this surrounding conducting liquid by comparing the performance of our system with and without such liquid. In addition, we also compare the performance of the proposed coil with that of a circular coil, a figure-eight coil, and the H-coil. Finally, in addition to its whole-brain stimulation capability (e.g. potentially useful for prophylaxis of epileptic patients) the system is also able to stimulate mainly one brain hemisphere, which may be useful in stroke rehabilitation, among other applications. PMID:25570015

Sousa, Sonia C P; Almeida, Jorge; Cavaleiro Miranda, Pedro; Salvador, Ricardo; Silvestre, Joao; Simoes, Hugo; Crespo, Paulo

2014-08-01

126

Occlusion of large atrial septal defects with a centering buttoned device: early clinical experience.  

PubMed

A feasibility clinical study was conducted for the transcatheter occlusion of large ostium secundum atrial septal defects with the centering buttoned device. The centering buttoned device is a modification of the regular buttoned device in which a centering counter-occluder is sutured at the central 40% portion of the occluder. During centering it is stretched, forming a parachute-shaped structure and pulling the occluder over the center of the defect. During buttoning, the counter-occluder forms a double figure eight, opposing the right atrial side of the atrial septum. Occlusion was performed in 12 patients aged 6 to 56 years. All had been rejected for transcatheter occlusion by the regular buttoned device, because of either their defect size or the lack of adequate septal rim. The defect size varied between 23 and 31 mm, and the device size varied between 45 and 60 mm. Nine had immediate effective occlusions of their defects and three residual shunts. One patient with unbuttoning had hemolysis at 2 weeks and underwent surgery. Early results of the transcatheter occlusion of large atrial septal defects are promising, and larger clinical trials are justified. PMID:8579033

Sideris, E B; Leung, M; Yoon, J H; Chen, C R; Lochan, R; Worms, A M; Rey, C; Meier, B

1996-02-01

127

The vertical disk structure of the edge-on spiral galaxy NGC 3079  

NASA Technical Reports Server (NTRS)

NGC 3079 is an edge-on SB(s)c galaxy at a redshift of 1225 km/s relative to the Local Group. Earlier researchers found a spectacular 'figure-eight' radio structure aligned along the minor axis of the galaxy, centered on the nucleus, and extending 3 kpc above and below the plane. The geometry of this structure and the evidence of unusually high nuclear gas velocities suggest that a wind-type outflow from the nucleus is taking place. The disk of NGC 3079 is also remarkable: it is extremely rich in H 2 regions and is the only unambiguous example of a galaxy outside M31 and our own Galaxy to exhibit 'Heiles-like' shells. Other researchers have also identified a nebulosity with a ragged X-shaped morphology formed by a system of lumpy filaments with individual lengths of 3 - 5 kpc. They suggest that this material is ambient halo gas entrained into the boundary layers of the nuclear outflow. The complex structure of the line emission in NGC 3079 makes this object an ideal target for an imaging spectroscopic study. The present paper reports the preliminary results of such a study.

Veilleux, S.; Bland-Hawthorn, Jonathan; Cecil, G.; Tully, R. B.

1993-01-01

128

Studies on magnetism and bioelectromagnetics for 45 years: from magnetic analog memory to human brain stimulation and imaging.  

PubMed

Forty-five years of studies on magnetism and bioelectromagnetics, in our laboratory, are presented. This article is prepared for the d'Arsonval Award Lecture. After a short introduction of our early work on magnetic analog memory, we review and discuss the following topics: (1) Magnetic nerve stimulation and localized transcranial magnetic stimulation (TMS) of the human brain by figure-eight coils; (2) Measurements of weak magnetic fields generated from the brain by superconducting quantum interference device (SQUID) systems, called magnetoencephalography (MEG), and its application in functional brain studies; (3) New methods of magnetic resonance imaging (MRI) for the imaging of impedance of the brain, called impedance MRI, and the imaging of neuronal current activities in the brain, called current MRI; (4) Cancer therapy and other medical treatments by pulsed magnetic fields; (5) Effects of static magnetic fields and magnetic control of cell orientation and cell growth; and (6) Effects of radio frequency magnetic fields and control of iron ion release and uptake from and into ferritins, iron cage proteins. These bioelectromagnetic studies have opened new horizons in magnetism and medicine, in particular for brain research and treatment of ailments such as depression, Parkinson's, and Alzheimer's diseases. PMID:22012916

Ueno, Shoogo

2012-01-01

129

Preliminary observations on the response of Chironex fleckeri (Cnidaria: Cubozoa: Chirodropida) to different colors of light.  

PubMed

Cubozoans are well known for their attraction to light and light-colored objects. Two highly venomous types are a public safety concern in Australian waters and elsewhere: Chironex fleckeri, long considered the world's deadliest animal and colloquially called the box jellyfish; and the irukandjis, a group of at least 10 species that cause various degrees of debilitating illness. We were asked by the tourism industry whether there might be a color of light that box jellyfish and irukandjis are not attracted to, such that nighttime diving activities might pose less risk of being stung. Our preliminary trials with Chironex fleckeri indicated a marked positive response to lights of white, red, yellow, green, orange, and blue. All colors elicited a strong and directed attraction to light; however, medusae slowed down their pulsation rate, streamed out their tentacles, and performed a series of figure-eight patterns back and forth through the lighted area when exposed to blue light, which we interpreted as feeding behavior. This compares curiously with a report subsequent to our testing, in which the small, mangrove-inhabiting cubomedusa Tripedalia cystophora and the beach-dwelling Chiropsella bronzie demonstrate a peak sensitivity to blue-green light in the region of 500 nm, and that the former is behaviorally attracted to blue and green light, but ignores red. This leaves open the possibility that Irukandji species, which are more closely related to Tripedalia than to Chironex, may be blind to red. PMID:18723637

Gershwin, Lisa-Ann; Dawes, Peter

2008-08-01

130

Neural Network Training by Integration of Adjoint Systems of Equations Forward in Time  

NASA Technical Reports Server (NTRS)

A method and apparatus for supervised neural learning of time dependent trajectories exploits the concepts of adjoint operators to enable computation of the gradient of an objective functional with respect to the various parameters of the network architecture in a highly efficient manner. Specifically. it combines the advantage of dramatic reductions in computational complexity inherent in adjoint methods with the ability to solve two adjoint systems of equations together forward in time. Not only is a large amount of computation and storage saved. but the handling of real-time applications becomes also possible. The invention has been applied it to two examples of representative complexity which have recently been analyzed in the open literature and demonstrated that a circular trajectory can be learned in approximately 200 iterations compared to the 12000 reported in the literature. A figure eight trajectory was achieved in under 500 iterations compared to 20000 previously required. Tbc trajectories computed using our new method are much closer to the target trajectories than was reported in previous studies.

Toomarian, Nikzad (Inventor); Barhen, Jacob (Inventor)

1999-01-01

131

Conformations of some lower-size large-ring cyclodextrins derived from conformational search with molecular dynamics and principal component analysis  

NASA Astrophysics Data System (ADS)

Computational studies were conducted on the conformations of some lower-size large-ring cyclodextrins, CDn (n = 11, 12, 13, 15, 16, 17). Principal component analysis (PCA) was applied for post-processing of trajectories from conformational search based on 100.0 ns molecular dynamics (MD) simulations. The dominant PCA modes for concerted motions of the macroring atoms were monitored in a lower-dimensions subspace. The first six lowest indexed principal components contribute more than 90% of the total atomic motions in all cases, with about 70% (CD12) to 90% (CD17) contribution coming from the three highest-eigenvalue principal components. Representative average geometries of the cyclodextrin macrorings were also obtained for the whole simulation and for the ten 10.0 ns time intervals of the simulation. We concluded that the whole set of structures could be sorted into two clearly distinguished groups, separated by the figure-eight conformation of CD14: (i) open bent boat-like macrorings (CD11 to CD13), and (ii) two winded single helical strands (an anti-parallel double helix with foldbacks at each end), CD15 to CD17, shaped as number eight for the odd-number-residues cases, CD15 and CD17. CD13 and CD14 mark the borderline between lower and higher flexibilities of the lower-size LR-CDs macrorings.

Ivanov, Petko

2012-02-01

132

Looking for Changes in Soil over Time  

NASA Technical Reports Server (NTRS)

The grinding teeth have worn away on the rock abrasion tool of NASA's Mars Exploration Rover Spirit (after exposing interiors of five time more rock targets than its design goal of three rocks) but the tool still has useful wire bristles for brushing targets. In this image, a figure-eight-like imprint in the Martian soil marks the spot where Spirit has begun examining subsurface deposits layer by layer. The circular indentations resulted from brushing by the rock abrasion tool, one of several instruments on the rover's robotic arm. As an effective brushing tool it is now fulfilling a soil profiling experiment on a target called 'Progress.'

The experiment is a multi-step process of carefully brushing away fine layers of soil and then using the Moessbauer and alpha particle X-ray spectrometers, microscopic imager, and panoramic camera to examine the exposed surfaces during the long Martian winter.

This view is a mosaic of exposures taken by Spirit's microscopic imager during the rover's 830th Martian day (May 4, 2006). The total area shown is about 6 centimeters (2.4 inches) square.

2006-01-01

133

The meandering instability of a viscous thread  

E-print Network

A viscous thread falling from a nozzle onto a surface exhibits the famous rope-coiling effect, in which the thread buckles to form loops. If the surface is replaced by a belt moving with speed $U$, the rotational symmetry of the buckling instability is broken and a wealth of interesting states are observed [See S. Chiu-Webster and J. R. Lister, J. Fluid Mech., {\\bf 569}, 89 (2006)]. We experimentally studied this "fluid mechanical sewing machine" in a new, more precise apparatus. As $U$ is reduced, the steady catenary thread bifurcates into a meandering state in which the thread displacements are only transverse to the motion of the belt. We measured the amplitude and frequency $\\omega$ of the meandering close to the bifurcation. For smaller $U$, single-frequency meandering bifurcates to a two-frequency "figure eight" state, which contains a significant $2\\omega$ component and parallel as well as transverse displacements. This eventually reverts to single-frequency coiling at still smaller $U$. More complex, ...

Morris, Stephen W; Ribe, Neil M; Lister, John R

2007-01-01

134

The Beam Pointing of Communication Stellite in Geosynchronous Inclined Orbit  

NASA Astrophysics Data System (ADS)

We assume that the KOREASAT fails the entry of the geostationary orbit due to the error at the apogee kick motor firing. A simulation is done for the satellite that has a geosynchronous orbit with a non-zero degree inclination angle due to the failure at the apogee kick motor caused by the unbalance of the fuel storage ad the spin of the thrust vector, etc. We analyzed the evolution of the orbit using the perturbation theory and calculated the changes of the eccentricity and the inclination. When a communication satellite has the figure eight trajectory, the beam point also traces the satellite. In this paper, we develop an algorithm to attack the above problem by stabilizing the beam point using the adjustment of the roll angle of the satellite. The spin action on the polarization plane that occurs when a satellite passes the ascending node and descending node affects the efficiency of the communication a lot, so we did another simulation for the better yaw angle adjustment for the KOREASAT to reduce the spin action on the polarization plane.

Kim, Bang-Yeop; Choi, Kyu-Hong

1995-06-01

135

Feasibility and clinical benefit of a suture-mediated closure device for femoral vein access after percutaneous edge-to-edge mitral valve repair.  

PubMed

Aims: We assessed feasibility, efficacy and safety of a suture-mediated closure device, Perclose Proglide® (Abbott Vascular Devices, Santa Clara, CA, USA), for closure of the femoral vein access after percutaneous MitraClip® (Abbott Vascular Devices) implantation. Methods and results: Venous access of 80 consecutive patients undergoing percutaneous mitral valve repair using the MitraClip device was managed either by manual compression, "figure eight" suture and compression bandage for 12 hours, or by applying the Proglide device for haemostasis after the procedure (40 patients each group). Patients with Proglide closure showed complete immediate haemostasis in 92.5% (37/40) and were immobilised with a compression bandage for only four hours. In the Proglide group, one arteriovenous fistula was observed and had to be treated by vascular surgery. The overall duration of stay on an intensive care unit was significantly reduced in the Proglide group (59.4±48.9 hours vs. 84.6±59.5 hours, p<0.005). Conclusions: Using a suture-mediated closure device for the femoral vein after percutaneous MitraClip implantation is feasible and safe. This allows earlier patient mobilisation and may reduce post-interventional duration of stay on an intensive care unit. PMID:24694560

Geis, Nicolas A; Pleger, Sven T; Chorianopoulos, Emmanuel; Müller, Oliver J; Katus, Hugo A; Bekeredjian, Raffi

2014-04-01

136

Routing and switching in optical networks: comparing the benefits of hybrid vs. router-only solutions  

NASA Astrophysics Data System (ADS)

The public network is rapidly moving from being a voice-optimized network that carries data, to a data-optimized network that will carry multiple services with IP as the predominant traffic. One of the key issues confronting carriers is the balance between circuit switching and packet switching in the core of the network. With the emergence of fast IP switch/routers, it is becoming possible to directly connect all ports on DWDM equipment directly on the router vs. connecting the router to DWDM infrastructure through an optical cross-connect. Comparing the costs of circuit switching and packet switching in the core of the network, a hybrid of packet and circuit switching solution proves more cost-effective than the pure packet switching whenever the port cost of the IP router is more than twice the port cost of the optical cross- connect. Furthermore, to enable cost effective evolution toward the converged network, the next generation of switching equipment will need to accommodate astronomical growth, while providing carriers with more flexibility in network design.

Chadwick, Peter; Moghaddam, Yassi

2000-10-01

137

Pixel structure for asymmetry removal in ToF 3D camera  

NASA Astrophysics Data System (ADS)

Most of time-of-flight (ToF) cameras have a 2-tap pixel structure for demodulating a reflected near infrared (NIR) from objects. In order to eliminate the asymmetry between two taps in the pixel, a ToF camera needs another measurement, which collects photo-generated electrons from reflected NIR by inverting the phase of clock signals to transfer gates. This asymmetry removal needs additional frame memories and suppresses the frame rate due to the additional timing budget. In this paper, we propose novel asymmetry removal scheme without timing and area overheads by employing 2×2 shared 2-tap pixels with cross-connected transfer gates. The 2-tap pixel is shared with neighbor pixels and transfer gates in the pixel are cross-connected between upper and lower pixels. In order to verify the proposed pixel architecture, an electron charge generated in floating diffusion is simulated. And then we try to calculate a depth from camera to objects using simulated electron charge and measure a linearity of depth. In simulation result, proposed pixel architecture has more linear graph than conventional pixel structure along the real distance of objects.

Kang, Byongmin; Shin, Jungsoon; Choi, Jaehyuk; Kim, James D. K.

2014-03-01

138

Effects of low-frequency repetitive transcranial magnetic stimulation on event-related potential P300  

NASA Astrophysics Data System (ADS)

The present study analyzed the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity. P300 latency of event-related potential (ERP) was used to evaluate the effects of low-frequency and short-term rTMS by stimulating the supramarginal gyrus (SMG), which is considered to be the related area of P300 origin. In addition, the prolonged stimulation effects on P300 latency were analyzed after applying rTMS. A figure-eight coil was used to stimulate left-right SMG, and intensity of magnetic stimulation was 80% of motor threshold. A total of 100 magnetic pulses were applied for rTMS. The effects of stimulus frequency at 0.5 or 1 Hz were determined. Following rTMS, an odd-ball task was performed and P300 latency of ERP was measured. The odd-ball task was performed at 5, 10, and 15 min post-rTMS. ERP was measured prior to magnetic stimulation as a control. Electroencephalograph (EEG) was measured at Fz, Cz, and Pz that were indicated by the international 10-20 electrode system. Results demonstrated that different effects on P300 latency occurred between 0.5-1 Hz rTMS. With 1 Hz low-frequency magnetic stimulation to the left SMG, P300 latency decreased. Compared to the control, the latency time difference was approximately 15 ms at Cz. This decrease continued for approximately 10 min post-rTMS. In contrast, 0.5 Hz rTMS resulted in delayed P300 latency. Compared to the control, the latency time difference was approximately 20 ms at Fz, and this delayed effect continued for approximately 15 min post-rTMS. Results demonstrated that P300 latency varied according to rTMS frequency. Furthermore, the duration of the effect was not similar for stimulus frequency of low-frequency rTMS.

Torii, Tetsuya; Sato, Aya; Iwahashi, Masakuni; Iramina, Keiji

2012-04-01

139

Physiological modules for generating discrete and rhythmic movements: action identification by a dynamic recurrent neural network.  

PubMed

In this study we employed a dynamic recurrent neural network (DRNN) in a novel fashion to reveal characteristics of control modules underlying the generation of muscle activations when drawing figures with the outstretched arm. We asked healthy human subjects to perform four different figure-eight movements in each of two workspaces (frontal plane and sagittal plane). We then trained a DRNN to predict the movement of the wrist from information in the EMG signals from seven different muscles. We trained different instances of the same network on a single movement direction, on all four movement directions in a single movement plane, or on all eight possible movement patterns and looked at the ability of the DRNN to generalize and predict movements for trials that were not included in the training set. Within a single movement plane, a DRNN trained on one movement direction was not able to predict movements of the hand for trials in the other three directions, but a DRNN trained simultaneously on all four movement directions could generalize across movement directions within the same plane. Similarly, the DRNN was able to reproduce the kinematics of the hand for both movement planes, but only if it was trained on examples performed in each one. As we will discuss, these results indicate that there are important dynamical constraints on the mapping of EMG to hand movement that depend on both the time sequence of the movement and on the anatomical constraints of the musculoskeletal system. In a second step, we injected EMG signals constructed from different synergies derived by the PCA in order to identify the mechanical significance of each of these components. From these results, one can surmise that discrete-rhythmic movements may be constructed from three different fundamental modules, one regulating the co-activation of all muscles over the time span of the movement and two others elliciting patterns of reciprocal activation operating in orthogonal directions. PMID:25278868

Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana M; Dan, Bernard; McIntyre, Joseph; Cheron, Guy

2014-01-01

140

Solar powered multipurpose remotely powered aircraft  

NASA Technical Reports Server (NTRS)

Environmental problems such as the depletion of the ozone layer and air pollution demand a change in traditional means of propulsion that is sensitive to the ecology. Solar-powered propulsion is a favorable alternative that is both ecologically harmless as well as cost effective. Integration of solar energy into designs ranging from futuristic vehicles to heating is, therefore, beneficial to society. The design and construction of a Multipurpose Remotely Piloted Vehicle (MPRPV) seeks to verify the feasibility of using solar propulsion as a primary fuel source. This task has been a year-long effort by a group of eight students, divided into four teams, each dealing with different aspects of the design. The aircraft was designed to take off, climb to the design altitude, fly in a sustained figure-eight flight path, and cruise for approximately one hour. This mission requires flight at Reynolds numbers between 150,000 and 200,000 and demands special considerations in the aerodynamic design to achieve flight in this regime. Optimal performance requires a lightweight configuration with both structural integrity and maximum power availability. The structural design and choice of solar cells for the propulsion were governed by weight, efficiency, and cost considerations. The final design is an MPRPV weighing 35 N that cruises at 7 m/s at the design altitude of 50 m. The configuration includes a wing composed of balsa and foam NACA 6409 airfoil sections and carbon fiber spars, a tail of similar construction, and a truss structure fuselage. The propulsion system consists of 98 12.5 percent-efficient solar cells donated by Mobil Solar, a NiCad battery for energy storage, and a folding propeller regulated by a lightweight and efficient control system. The airfoils and propeller chosen for the design were researched and tested during the design process.

1991-01-01

141

Prefrontal cortex and hippocampus subserve different components of working memory in rats  

PubMed Central

Both the medial prefrontal cortex (mPFC) and hippocampus are implicated in working memory tasks in rodents. Specifically, it has been hypothesized that the mPFC is primarily engaged in the temporary storage and processing of information lasting from a subsecond to several seconds, while the hippocampal function becomes more critical as the working memory demand extends into longer temporal scales. Although these structures may be engaged in a temporally separable manner, the extent of their contributions in the “informational content” of working memory remains unclear. To investigate this issue, the mPFC and dorsal hippocampus (dHPC) were temporarily inactivated via targeted infusions of the GABAA receptor agonist muscimol in rats prior to their performance on a delayed alternation task (DAT), employing an automated figure-eight maze that required the animals to make alternating arm choice responses after 3-, 30-, and 60-sec delays for water reward. We report that inactivation of either the mPFC or dHPC significantly reduced DAT at all delay intervals tested. However, there were key qualitative differences in the behavioral effects. Specifically, mPFC inactivation selectively impaired working memory (i.e., arm choice accuracy) without altering reference memory (i.e., the maze task rule) and arm choice response latencies. In contrast, dHPC inactivation increased both reference memory errors and arm choice response latencies. Moreover, dHPC, but not mPFC, inactivation increased the incidence of successive working memory errors. These results suggest that while both the mPFC and hippocampus are necessarily involved in DAT, they seem to process different informational components associated with the memory task. PMID:18285468

Yoon, Taejib; Okada, Jeffrey; Jung, Min W.; Kim, Jeansok J.

2008-01-01

142

NASA advanced aeronautics design solar powered remotely piloted vehicle  

NASA Technical Reports Server (NTRS)

Environmental problems such as the depletion of the ozone layer and air pollution demand a change in traditional means of propulsion that is sensitive to the ecology. Solar powered propulsion is a favorable alternative that is both ecologically harmless as well as cost effective. Integration of solar energy into designs ranging from futuristic vehicles to heating is beneficial to society. The design and construction of a Multi-Purpose Remotely Piloted Vehicle (MPRPV) seeks to verify the feasibility of utilizing solar propulsion as a primary fuel source. This task has been a year long effort by a group of ten students, divided into five teams, each dealing with different aspects of the design. The aircraft was designed to take-off, climb to the design altitude, fly in a sustained figure-eight flight path, and cruise for approximately one hour. This mission requires flight at Reynolds numbers between 150,000 and 200,000 and demands special considerations in the aerodynamic design in order to achieve flight in this regime. Optimal performance requires a light weight configuration with both structural integrity and maximum power availability. The structure design and choice of solar cells for the propulsion was governed by the weight, efficiency, and cost considerations. The final design is a MPRPV weighting 35 N which cruises 7 m/s at the design altitude of 50 m. The configuration includes a wing composed of balsa and foam NACA 6409 airfoil sections and carbon fiber spars, a tail of similar construction, and a truss structure fuselage. The propulsion system consists of 98 10 percent efficient solar cells donated by Mobil Solar, a NiCad battery for energy storage, and a folding propeller regulated by a lightweight and efficient control system. The airfoils and propeller chosen for the design were research and tested during the design process.

Elario, David S.; Guillmette, Neal H.; Lind, Gregory S.; Webster, Jonathan D.; Ferreira, Michael J.; Konstantakis, George C.; Marshall, David L.; Windt, Cari L.

1991-01-01

143

Physiological modules for generating discrete and rhythmic movements: action identification by a dynamic recurrent neural network  

PubMed Central

In this study we employed a dynamic recurrent neural network (DRNN) in a novel fashion to reveal characteristics of control modules underlying the generation of muscle activations when drawing figures with the outstretched arm. We asked healthy human subjects to perform four different figure-eight movements in each of two workspaces (frontal plane and sagittal plane). We then trained a DRNN to predict the movement of the wrist from information in the EMG signals from seven different muscles. We trained different instances of the same network on a single movement direction, on all four movement directions in a single movement plane, or on all eight possible movement patterns and looked at the ability of the DRNN to generalize and predict movements for trials that were not included in the training set. Within a single movement plane, a DRNN trained on one movement direction was not able to predict movements of the hand for trials in the other three directions, but a DRNN trained simultaneously on all four movement directions could generalize across movement directions within the same plane. Similarly, the DRNN was able to reproduce the kinematics of the hand for both movement planes, but only if it was trained on examples performed in each one. As we will discuss, these results indicate that there are important dynamical constraints on the mapping of EMG to hand movement that depend on both the time sequence of the movement and on the anatomical constraints of the musculoskeletal system. In a second step, we injected EMG signals constructed from different synergies derived by the PCA in order to identify the mechanical significance of each of these components. From these results, one can surmise that discrete-rhythmic movements may be constructed from three different fundamental modules, one regulating the co-activation of all muscles over the time span of the movement and two others elliciting patterns of reciprocal activation operating in orthogonal directions. PMID:25278868

Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana M.; Dan, Bernard; McIntyre, Joseph; Cheron, Guy

2014-01-01

144

3DScapeCS: application of three dimensional, parallel, dynamic network visualization in Cytoscape  

PubMed Central

Background The exponential growth of gigantic biological data from various sources, such as protein-protein interaction (PPI), genome sequences scaffolding, Mass spectrometry (MS) molecular networking and metabolic flux, demands an efficient way for better visualization and interpretation beyond the conventional, two-dimensional visualization tools. Results We developed a 3D Cytoscape Client/Server (3DScapeCS) plugin, which adopted Cytoscape in interpreting different types of data, and UbiGraph for three-dimensional visualization. The extra dimension is useful in accommodating, visualizing, and distinguishing large-scale networks with multiple crossed connections in five case studies. Conclusions Evaluation on several experimental data using 3DScapeCS and its special features, including multilevel graph layout, time-course data animation, and parallel visualization has proven its usefulness in visualizing complex data and help to make insightful conclusions. PMID:24225050

2013-01-01

145

Fbis report. Science and technology: China, October 18, 1995  

SciTech Connect

;Partial Contents: Nanomaterials Fabrication, Applications Research Advances Noted; CAST Announces World`s First Space-Grown Large-Diameter GaAs Monocrystal; Assay of Antiviral Activity of Antisense Phosphorothioate Oligodeoxynucleotide Against Dengue Virus; Expression and Antigenicity of Chimeric Proteins of Cholera Toxin B Subunit With Hepatitis C Virus; CNCOFIEC Signs Agreement With IBM for New Intelligent Building; Latest Reports on Optical Computing, Memory; BIDC To Introduce S3 Company`s Multimedia Accelerator Chipset; Virtual Private PCN Ring Network Based on ATM VP Cross-Connection; Beijing Gets Nation`s First Frame Relay Network; Situation of Power Industry Development and International Cooperation; Diagrams of China`s Nuclear Waste Containment Vessels; Chinese-Developed Containment Vessel Material Reaches World Standards; Second Fuel Elements for Qinshan Plant Passes Inspection; and Geothermal Deep-Well Electric Pump Technology Developed.

NONE

1995-10-18

146

Waste Isolation Pilot Plant Biennial Environmental Compliance Report  

SciTech Connect

This Biennial Environmental Compliance Report (BECR) documents environmental regulatory compliance at the Waste Isolation Pilot Plant (WIPP), a facility designed for the safe disposal of transuranic (TRU) radioactive waste, for the reporting period of April 1, 1998, to March 31, 2000. As required by the WIPP Land Withdrawal Act (LWA)(Public Law [Pub. L.] 102-579, and amended by Pub. L. 104-201), the BECR documents U.S. Department of Energy (DOE) Carlsbad Area Office's (hereinafter the ''CAO'') compliance with applicable environmental protection laws and regulations implemented by agencies of the federal government and the state of New Mexico. An issue was identified in the 1998 BECR relating to a potential cross-connection between the fire-water systems and the site domestic water system. While the CAO and its managing and operating contractor (hereinafter the ''MOC'') believe the site was always in compliance with cross-connection control requirements, hardware and procedural upgrades w ere implemented in March 1999 to strengthen its compliance posture. Further discussion of this issue is presented in section 30.2.2 herein. During this reporting period WIPP received two letters and a compliance order alleging violation of certain requirements outlined in section 9(a)(1) of the LWA. With the exception of one item, pending a final decision by the New Mexico Environment Department (NMED), all alleged violations have been resolved without the assessment of fines or penalties. Non-mixed TRU waste shipments began on March 26, 1999. Shipments continued through November 26, 1999, the effective date of the Waste Isolation Pilot Plant Hazardous Waste Facility Permit (NM4890139088-TSDF). No shipments regulated under the Hazardous Waste Facility Permit were received at WIPP during this BECR reporting period.

Westinghouse TRU Solutions

2000-12-01

147

Full vector spherical harmonic analysis of the Holocene geomagnetic field  

NASA Astrophysics Data System (ADS)

High-quality time-series paleomagnetic measurements have been used to derive spherical harmonic models of Earth's magnetic field for the past 2,000 years. A newly-developed data compilation, PSVMOD2.0 consists of time-series directional and intensity records that significantly improve the data quality and global distribution used to develop previous spherical harmonic models. PSVMOD2.0 consists of 185 paleomagnetic time series records from 85 global sites, including 30 full-vector records (inclination, declination and intensity). It includes data from additional sites in the Southern Hemisphere and Arctic and includes globally distributed sediment relative paleointensity records, significantly improving global coverage over previous models. PSVMOD2.0 records have been assessed in a series of 7 regional intercomparison studies, four in the Northern Hemisphere and 3 in the southern hemisphere. Comparisons on a regional basis have improved the quality and chronology of the data and allowed investigation of spatial coherence and the scale length associated with paleomagnetic secular variation (PSV) features. We have developed a modeling methodology based on nonlinear inversion of the PSVMOD2.0 directional and intensity records. Models of the geomagnetic field in 100-year snapshots have been derived for the past 2,000 with the ultimate goal of developing models spanning the past 8,000 years. We validate the models and the methodology by comparing with the GUFM1 historical models during the 400-year period of overlap. We find that the spatial distribution of sites and quality of data are sufficient to derive models that agree with GUFM1 in the large-scale characteristics of the field. We use the the models derived in this study to downward continue the field to the core-mantle boundary and examine characteristics of the large-scale structure of the magnetic field at the source region. The derived models are temporally consistent from one epoch to the next and exhibit many of the expected characteristics of the field over time (high-latitude flux lobes, South Atlantic reverse flux patch, north pole reverse or null flux region).

Richardson, Marcia

148

Adaptive Morphological Feature-Based Object Classifier for a Color Imaging System  

NASA Technical Reports Server (NTRS)

Utilizing a Compact Color Microscope Imaging System (CCMIS), a unique algorithm has been developed that combines human intelligence along with machine vision techniques to produce an autonomous microscope tool for biomedical, industrial, and space applications. This technique is based on an adaptive, morphological, feature-based mapping function comprising 24 mutually inclusive feature metrics that are used to determine the metrics for complex cell/objects derived from color image analysis. Some of the features include: Area (total numbers of non-background pixels inside and including the perimeter), Bounding Box (smallest rectangle that bounds and object), centerX (x-coordinate of intensity-weighted, center-of-mass of an entire object or multi-object blob), centerY (y-coordinate of intensity-weighted, center-of-mass, of an entire object or multi-object blob), Circumference (a measure of circumference that takes into account whether neighboring pixels are diagonal, which is a longer distance than horizontally or vertically joined pixels), . Elongation (measure of particle elongation given as a number between 0 and 1. If equal to 1, the particle bounding box is square. As the elongation decreases from 1, the particle becomes more elongated), . Ext_vector (extremal vector), . Major Axis (the length of a major axis of a smallest ellipse encompassing an object), . Minor Axis (the length of a minor axis of a smallest ellipse encompassing an object), . Partial (indicates if the particle extends beyond the field of view), . Perimeter Points (points that make up a particle perimeter), . Roundness [(4(pi) x area)/perimeter(squared)) the result is a measure of object roundness, or compactness, given as a value between 0 and 1. The greater the ratio, the rounder the object.], . Thin in center (determines if an object becomes thin in the center, (figure-eight-shaped), . Theta (orientation of the major axis), . Smoothness and color metrics for each component (red, green, blue) the minimum, maximum, average, and standard deviation within the particle are tracked. These metrics can be used for autonomous analysis of color images from a microscope, video camera, or digital, still image. It can also automatically identify tumor morphology of stained images and has been used to detect stained cell phenomena (see figure).

McDowell, Mark; Gray, Elizabeth

2009-01-01

149

Correlation among fibrillation, defibrillation, and cardiac pacing.  

PubMed

An electrical stimulus must create an electric field of approximately 1 V/cm in the extracellular space to stimulate myocardium during diastole. To initiate fibrillation by premature stimulation during the vulnerable period or to defibrillate, an extracellular electric field of approximately 6 V/cm is required, a value approximately six times greater than that necessary for diastolic pacing. Yet, the current strength of the pulse given to the stimulating electrode to initiate fibrillation or to defibrillate is much greater than six times the diastolic pacing threshold. The ventricular fibrillation threshold is typically 40 times greater than the diastolic pacing threshold expressed in terms of current. The defibrillation threshold in terms of current is typically thousands of times greater than the diastolic pacing threshold. The reason that these thresholds vary so much more in terms of stimulus current than in terms of extracellular potential gradient is that each of the three thresholds requires creation of the required potential gradient at different distances from the stimulating electrode. Pacing requires a potential gradient of approximately 1 V/cm only in a small liminal volume of tissue immediately adjacent to the electrode. Initiation of ventricular fibrillation by premature stimulation during the vulnerable period requires a potential gradient of approximately 6 V/cm about 1 cm away from the stimulating electrode to allow sufficient space for the central common pathway of a figure-eight reentrant circuit to form. Since the potential gradient falls off rapidly with distance from the stimulating electrode, a stimulating current about 40 times greater than the diastolic pacing threshold is required to generate an electric field of 6 V/cm approximately 1 cm away from the stimulating electrode. Defibrillation requires an electric field of approximately 6 V/cm throughout all or almost all of the ventricular myocardium. Since some portions of the ventricles can be more than 10 cm away from the defibrillation electrodes, a shock of several amps is required to create this field, a current thousands of times greater than the pacing threshold. PMID:7777416

Ideker, R E; Zhou, X; Knisley, S B

1995-03-01

150

Death and Transfiguration in Static Staphylococcus epidermidis Cultures  

PubMed Central

The overwhelming majority of bacteria live in slime embedded microbial communities termed biofilms, which are typically adherent to a surface. However, when several Staphylococcus epidermidis strains were cultivated in static liquid cultures, macroscopic aggregates were seen floating within the broth and also sedimented at the test tube bottom. Light- and electron microscopy revealed that early-stage aggregates consisted of bacteria and extracellular matrix, organized in sheet-like structures. Perpendicular under the sheets hung a network of periodically arranged, bacteria-associated strands. During the extended cultivation, the strands of a subpopulation of aggregates developed into cross-connected wall-like structures, in which aligned bacteria formed the walls. The resulting architecture had a compartmentalized appearance. In late-stage cultures, the wall-associated bacteria disintegrated so that, henceforth, the walls were made of the coalescing remnants of lysed bacteria, while the compartment-like organization remained intact. At the same time, the majority of strand-containing aggregates with associated culturable bacteria continued to exist. These observations indicate that some strains of Staphylococcus epidermidis are able to build highly sophisticated structures, in which a subpopulation undergoes cell lysis, presumably to provide continued access to nutrients in a nutrient-limited environment, whilst maintaining structural integrity. PMID:24964210

Schaudinn, Christoph; Stoodley, Paul; Hall-Stoodley, Luanne; Gorur, Amita; Remis, Jonathan; Wu, Siva; Auer, Manfred; Hertwig, Stefan; Guerrero-Given, Debbie; Hu, Fen Ze; Ehrlich, Garth D.; Costerton, John William; Robinson, Douglas H.; Webster, Paul

2014-01-01

151

Wastewater characterization survey, Plattsburgh AFB, New York. Final report  

SciTech Connect

The USAFOEHL conducted a survey characterizing the wastewater in the Plattsburgh AFB sanitary, storm, and surface-water discharges from the base and determining if applicable discharge standards are being violated. A total of 31 sampling sites were evaluated including 12 sanitary, 13 surface, and 6 storm-water sources. Priority pollutants were found in samples from the sanitary and storm sewers and in the streams leaving the base. Recommendations were: (1) Combustible-gas detection sytems should be installed in lift stations. (2) A comprehensive hazardous-waste survey should be conducted to identify the source of the contaminants. (3) Respirators should be worn by personnel entering the wet well of lift stations, Building 2291. (4) Alternates for achieving better oil/water separation should be investigated. (5) The possibility of cross connections between the sanitary and storm systems should be investigated. (6) Oil/water separators discharge should be determined and should be connected to the sanitary sewer system. (7) Streams should be monitored for ammonia to avoid aquatic toxicity problems. (8) The BOD/COD ration should be determined by monitoring these parameters in the stream flowing through Copeland Oil property. (9) Additional analysis should be conducted on the seepage from the marina beach area. (10) A hazardous-material training program should be instituted.

Binovi, R.D.; Riojas, A.H.; Spakowicz, M.R.

1987-05-01

152

IC design of low power, wide tuning range VCO in 90 nm CMOS technology  

NASA Astrophysics Data System (ADS)

A low power VCO with a wide tuning range and low phase noise has been designed and realized in a standard 90 nm CMOS technology. A newly proposed current-reuse cross-connected pair is utilized as a negative conductance generator to compensate the energy loss of the resonator. The supply current is reduced by half compared to that of the conventional LC-VCO. An improved inversion-mode MOSFET (IMOS) varactor is introduced to extend the capacitance tuning range from 32.8% to 66%. A detailed analysis of the proposed varactor is provided. The VCO achieves a tuning range of 27–32.5 GHz, exhibiting a frequency tuning range (FTR) of 18.4% and a phase noise of ?101.38 dBc/Hz at 1 MHz offset from a 30 GHz carrier, and shows an excellent FOM of ?185 dBc/Hz. With the voltage supply of 1.5 V, the core circuit of VCO draws only 2.1 mA DC current.

Zhu, Li; Zhigong, Wang; Zhiqun, Li; Qin, Li; Faen, Liu

2014-12-01

153

Metro Optical Networks for Homeland Security  

NASA Astrophysics Data System (ADS)

Metro optical networks provide an enticing opportunity for strengthening homeland security. Many existing and emerging fiber-optic networks can be adapted for enhanced security applications. Applications include airports, theme parks, sports venues, and border surveillance systems. Here real-time high-quality video and captured images can be collected, transported, processed, and stored for security applications. Video and data collection are important also at correctional facilities, courts, infrastructure (e.g., dams, bridges, railroads, reservoirs, power stations), and at military and other government locations. The scaling of DWDM-based networks allows vast amounts of data to be collected and transported including biometric features of individuals at security check points. Here applications will be discussed along with potential solutions and challenges. Examples of solutions to these problems are given. This includes a discussion of metropolitan aggregation platforms for voice, video, and data that are SONET compliant for use in SONET networks and the use of DWDM technology for scaling and transporting a variety of protocols. Element management software allows not only network status monitoring, but also provides optimized allocation of network resources through the use of optical switches or electrical cross connects.

Bechtel, James H.

154

Performance requirements for semitransparent DWDM networks  

NASA Astrophysics Data System (ADS)

Required limits of transmission distance, nodes cascadability and grade of transparency (number of regenerators) are presented to implement semi-transparent DWDM backbone networks. Results are based on OSNR performance of three realistic optical network scenarios. Optical transmission impairments are key issues for transparent optical networks. To improve transmission in an optical network one can use forward error correction (FEC), Raman amplification, robust modulation formats tolerant to non-linear effects and noise, optimised dispersion maps, semi-transparent OXC architectures with selective 3R or 2R regeneration and reduction of losses in the optical cross connector (OXCs) architectures. In a typical optical network with mesh topology, a transmitted optical signal is expected to traverse several nodes connecting any source-destination pair. The cascadability limit of transparent optical cross-connect (OXC) nodes and the transmission distance between OXC nodes are crucial network design parameters. The required limits of transmission distance, OXC nodes cascadability and number of regenerators per node are presented for DWDM backbone networks. OXC architectures with low loss components and cost effective distributive amplification is required to facilitate a high OSNR and reduce the regeneration rate of semi-transparent networks. OXC architectures with OSNR below 36.7 dB are capable of reducing the regeneration rate to 13% for realistic network topologies.

Castanon, Gerardo A.

2004-10-01

155

Investigating brain connectivity heritability in a twin study using diffusion imaging data  

PubMed Central

Heritability of brain anatomical connectivity has been studied with diffusion-weighted imaging (DWI) mainly by modeling each voxel's diffusion pattern as a tensor (e.g., to compute fractional anisotropy), but this method cannot accurately represent the many crossing connections present in the brain. We hypothesized that different brain networks (i.e., their component fibers) might have different heritability and we investigated brain connectivity using High Angular Resolution Diffusion Imaging (HARDI) in a cohort of twins comprising 328 subjects that included 70 pairs of monozygotic and 91 pairs of dizygotic twins. Water diffusion was modeled in each voxel with a Fiber Orientation Distribution (FOD) function to study heritability for multiple fiber orientations in each voxel. Precision was estimated in a test–retest experiment on a sub-cohort of 39 subjects. This was taken into account when computing heritability of FOD peaks using an ACE model on the monozygotic and dizygotic twins. Our results confirmed the overall heritability of the major white matter tracts but also identified differences in heritability between connectivity networks. Inter-hemispheric connections tended to be more heritable than intra-hemispheric and cortico-spinal connections. The highly heritable tracts were found to connect particular cortical regions, such as medial frontal cortices, postcentral, paracentral gyri, and the right hippocampus. PMID:24973604

Shen, Kai-Kai; Rose, Stephen; Fripp, Jurgen; McMahon, Katie L.; de Zubicaray, Greig I.; Martin, Nicholas G.; Thompson, Paul M.; Wright, Margaret J.; Salvado, Olivier

2014-01-01

156

GMPLS-based control plane for optical networks: early implementation experience  

NASA Astrophysics Data System (ADS)

Generalized Multi-Protocol Label Switching (GMPLS) extends MPLS signaling and Internet routing protocols to provide a scalable, interoperable, distributed control plane, which is applicable to multiple network technologies such as optical cross connects (OXCs), photonic switches, IP routers, ATM switches, SONET and DWDM systems. It is intended to facilitate automatic service provisioning and dynamic neighbor and topology discovery across multi-vendor intelligent transport networks, as well as their clients. Efforts to standardize such a distributed common control plane have reached various stages in several bodies such as the IETF, ITU and OIF. This paper describes the design considerations and architecture of a GMPLS-based control plane that we have prototyped for core optical networks. Functional components of GMPLS signaling and routing are integrated in this architecture with an application layer controller module. Various requirements including bandwidth, network protection and survivability, traffic engineering, optimal utilization of network resources, and etc. are taken into consideration during path computation and provisioning. Initial experiments with our prototype demonstrate the feasibility and main benefits of GMPLS as a distributed control plane for core optical networks. In addition to such feasibility results, actual adoption and deployment of GMPLS as a common control plane for intelligent transport networks will depend on the successful completion of relevant standardization activities, extensive interoperability testing as well as the strengthening of appropriate business drivers.

Liu, Hang; Pendarakis, Dimitrios; Komaee, Nooshin; Saha, Debanjan

2002-07-01

157

Water security: the importance of designing dual use into solutions  

NASA Astrophysics Data System (ADS)

Water infrastructure needs in the US are expected to exceed a cost of over 300 billion dollars in the coming years. While security has become a priority since 9/11 budgets for this expenditure are often constrained. This necessitates that solutions be dual use in nature. Since 9/11 numerous communities have installed multi-parameter monitoring stations in the distribution system as early warning systems for potential water security threats. These systems have recorded large streams of data relevant to water quality in the distribution systems. In this study data streams from a number of communities are analyzed for pertinent information as to the health and operation of the distribution system. Changes in water quality are correlated with known causes attributable to day-to-day operational changes and also anomalous events (pipe bursts, accidental back flows, cross connections, chemical over feeds, treatment plant problems, nitrification events, etc.). Information concerning what action was taken to ameliorate the problem will also be linked to the data for the identified events thus demonstrating dual use for these systems.

Kroll, Dan

2009-05-01

158

Fiber-channel trade-off for reducing collisions in slotted single-hop optical packet-switched networks  

NASA Astrophysics Data System (ADS)

The next-generation Internet should be based on high-capacity agile all-optical networks. A single-hop time-slotted all-optical packet-switched network is studied as a potential candidate for the ultra-high-speed next-generation all-optical metro network. This structure is composed of an all-optical wavelength-selective cross-connect core switch and a number of edge switches connected to the core switch in a star physical topology. Since optical packet switching (OPS) uses random medium access control, contention is the major problem for this network. Contention resolution techniques are used to resolve the contention. However, contention resolution hardware such as optical buffers and wavelength converters are expensive. In addition, optical buffers are complex and bulky. Therefore, we do not use contention resolution hardware in this network. Instead, we discuss and analyze the contention avoidance issue for such a network. Using more fibers and using additional wavelength channels to carry the same traffic are two schemes that can be used to reduce contention in OPS networks. We develop a cost model in order to optimize the number of fibers and additional channels required to achieve a given loss rate.

Ghaffar Pour Rahbar, Akbar; Yang, Oliver

2007-07-01

159

Disorganization of Equilibrium Directional Interactions in the Brain Motor Network of Parkinson's disease: New Insight of Resting State Analysis Using Granger Causality and Graphical Approach  

PubMed Central

Parkinson's disease (PD) is a progressive neurological disorder characterized by tremor, rigidity, and slowness of movements. Particular changes related to various pathological attacks in PD could result in causal interactions of the brain network from resting state functional magnetic resonance imaging (rs-fMRI) data. In this paper, we aimed to disclose the network structure of the directed influences over the brain using multivariate Granger causality analysis and graph theory in patients with PD as compared with control group. rs-fMRI at rest from 10 PD patients and 10 controls were analyzed. Topological properties of the networks showed that information flow in PD is smaller than that in healthy individuals. We found that there is a balanced local network in healthy control group, including positive pair-wise cross connections between caudate and cerebellum and reciprocal connections between motor cortex and caudate in the left and right hemispheres. The results showed that this local network is disrupted in PD due to disturbance of the interactions in the motor networks. These findings suggested alteration of the functional organization of the brain in the resting state that affects the information transmission from and to other brain regions related to both primary dysfunctions and higher-level cognition impairments in PD. Furthermore, we showed that regions with high degree values could be detected as betweenness centrality nodes. Our results demonstrate that properties of small-world connectivity could also recognize and quantify the characteristics of directed influence brain networks in PD. PMID:24098860

Ghasemi, Mahdieh; Mahloojifar, Ali

2013-01-01

160

Geochemical heterogeneity in a small, stratigraphically complex moraine aquifer system (Ontario, Canada): Interpretation of flow and recharge using multiple geochemical parameters  

USGS Publications Warehouse

The Waterloo Moraine is a stratigraphically complex system and is the major water supply to the cities of Kitchener and Waterloo in Ontario, Canada. Despite over 30 years of investigation, no attempt has been made to unify existing geochemical data into a single database. A composite view of the moraine geochemistry has been created using the available geochemical information, and a framework created for geochemical data synthesis of other similar flow systems. Regionally, fluid chemistry is highly heterogeneous, with large variations in both water type and total dissolved solids content. Locally, upper aquifer units are affected by nitrate and chloride from fertilizer and road salt. Typical upper-aquifer fluid chemistry is dominated by calcium, magnesium, and bicarbonate, a result of calcite and dolomite dissolution. Evidence also suggests that ion exchange and diffusion from tills and bedrock units accounts for some elevated sodium concentrations. Locally, hydraulic "windows" cross connect upper and lower aquifer units, which are typically separated by a clay till. Lower aquifer units are also affected by dedolomitization, mixing with bedrock water, and locally, upward diffusion of solutes from the bedrock aquifers. A map of areas where aquifer units are geochemically similar was constructed to highlight areas with potential hydraulic windows. ?? 2010 Springer-Verlag.

Stotler, R.L.; Frape, S.K.; El Mugammar, H.T.; Johnston, C.; Judd-Henrey, I.; Harvey, F.E.; Drimmie, R.; Jones, J.P.

2011-01-01

161

Review of Campylobacter spp. in drinking and environmental waters.  

PubMed

Consumption of contaminated drinking water is a significant cause of Campylobacter infections. Drinking water contamination is known to result from septic seepage and wastewater intrusion into non-disinfected sources of groundwater and occasionally from cross-connection into drinking water distribution systems. Wastewater effluents, farm animals and wild birds are the primary sources contributing human-infectious Campylobacters in environmental waters, impacting on recreational activities and drinking water sources. Culturing of Campylobacter entails time-consuming steps that often provide qualitative or semi-quantitative results. Viable but non-culturable forms due to environmental stress are not detected, and thus may result in false-negative assessments of Campylobacter risks from drinking and environmental waters. Molecular methods, especially quantitative PCR applications, are therefore important to use in the detection of environmental Campylobacter spp. Processing large volumes of water may be required to reach the desired sensitivity for either culture or molecular detection methods. In the future, applications of novel molecular techniques such as isothermal amplification and high-throughput sequencing applications are awaited to develop and become more affordable and practical in environmental Campylobacter research. The new technologies may change the knowledge on the prevalence and pathogenicity of the different Campylobacter species in the water environment. PMID:23810971

Pitkänen, Tarja

2013-10-01

162

Posterior mini-incision hamstring harvest.  

PubMed

Many orthopedists looking for alternatives to autograft bone-patellar-tendon-bone grafts are uncertain of their ability to harvest a hamstring graft of adequate length. They may use an allograft instead for this reason despite recent reports of high failure rates. This article presents step-by-step instructions for a posterior mini-incision hamstring harvest that offers a safe and simple method of reliably harvesting sufficient hamstring for 4 or 6 strand repair, while using tiny incisions for excellent cosmesis and minimal pain. Access from the posterior mini-incision allows easy identification and differentiation of the semitendinosus and gracilis (Gr) tendons, as well as precise placement of the anterior mini-incision for tibial tunnel drilling and fixation. Most importantly sectioning of the intertendinous cross-connections is performed under easy direct vision posteriorly, instead of at a distance from the typical anterior incision under retractors. This prevents the tendons from being cut too short by the tendon stripper and is particularly useful in large patients. In addition to the surgical procedure, details on the required equipment are presented. PMID:20160624

Prodromos, Chadwick C

2010-03-01

163

Geochemical heterogeneity in a small, stratigraphically complex moraine aquifer system (Ontario, Canada): interpretation of flow and recharge using multiple geochemical parameters  

NASA Astrophysics Data System (ADS)

The Waterloo Moraine is a stratigraphically complex system and is the major water supply to the cities of Kitchener and Waterloo in Ontario, Canada. Despite over 30 years of investigation, no attempt has been made to unify existing geochemical data into a single database. A composite view of the moraine geochemistry has been created using the available geochemical information, and a framework created for geochemical data synthesis of other similar flow systems. Regionally, fluid chemistry is highly heterogeneous, with large variations in both water type and total dissolved solids content. Locally, upper aquifer units are affected by nitrate and chloride from fertilizer and road salt. Typical upper-aquifer fluid chemistry is dominated by calcium, magnesium, and bicarbonate, a result of calcite and dolomite dissolution. Evidence also suggests that ion exchange and diffusion from tills and bedrock units accounts for some elevated sodium concentrations. Locally, hydraulic "windows" cross connect upper and lower aquifer units, which are typically separated by a clay till. Lower aquifer units are also affected by dedolomitization, mixing with bedrock water, and locally, upward diffusion of solutes from the bedrock aquifers. A map of areas where aquifer units are geochemically similar was constructed to highlight areas with potential hydraulic windows.

Stotler, Randy L.; Frape, Shaun K.; El Mugammar, Humam Taha; Johnston, Craig; Judd-Henrey, Ian; Harvey, F. Edwin; Drimmie, Robert; Jones, Jon Paul

2011-02-01

164

Smart repeater system for communications interoperability during multi-agency law enforcement operations  

SciTech Connect

A prototype smart repeater that provides interoperability capabilities for radio communication systems in multi-agency and multi-user scenarios is being developed by the Oak Ridge National Laboratory. The smart repeater functions as a deployable communications platform that can be dynamically reconfigured to cross-link the radios of participating federal, state, and local government agencies. This interconnection capability improves the coordination and execution of multi-agency operations, including coordinated law enforcement activities and general emergency or disaster response scenarios. The repeater provides multiple channels of operation in the 30--50, 118--136, 138--174, and 403--512 MHz land mobile communications and aircraft bands while providing the ability to cross-connect among multiple frequencies, bands, modulation types, and encryption formats. Additionally, two telephone interconnects provide links to the fixed and cellular telephone networks. The 800- and 900-MHz bands are not supported by the prototype, but the modular design of the system accommodates future retrofits to extend frequency capabilities with minimal impact to the system. Configuration of the repeater is through a portable personal computer with a Windows-based graphical interface control screen that provides dynamic reconfiguration of network interconnections and formats.

Crutcher, R.I.; Jones, R.W.; Moore, M.R.; Smith, S.F.; Tolley, A.L. [Oak Ridge National Lab., TN (United States); Rochelle, R.W. [Univ. of Tennessee, Knoxville, TN (United States). Electrical Engineering Dept.

1996-12-31

165

Pressure-driven ballistic Kelvin's water dropper for energy harvesting.  

PubMed

In this paper, we introduce a microfluidic-based self-excited energy conversion system inspired by Kelvin's water dropper but driven by inertia instead of gravity. Two micro water jets are produced by forcing water through two micropores by overpressure. The jets break up into microdroplets which are inductively charged by electrostatic gates. The droplets land on metal targets which are gradually charged up to high voltages. Targets and electrostatic gates are cross-connected in a way similar to Kelvin's water dropper. Application of pressure as driving force instead of gravity as in Kelvin's dropper allows for much higher energy densities. To prevent overcharging of the droplets by the inductive mechanism and consequent droplet loss by repulsion from the target as in Kelvin's water dropper, a voltage divider using inversely connected diodes was introduced in our system to control the charge induction providing self-limiting positive feedback by the diode characteristics. A maximal 18% energy conversion efficiency was obtained with the diode-gated system. PMID:25112848

Xie, Yanbo; de Boer, Hans L; Sprenkels, Ad J; van den Berg, Albert; Eijkel, Jan C T

2014-11-01

166

Design and implementation of a RF powering circuit for RFID tags or other batteryless embedded devices.  

PubMed

A RF powering circuit used in radio-frequency identification (RFID) tags and other batteryless embedded devices is presented in this paper. The RF powering circuit harvests energy from electromagnetic waves and converts the RF energy to a stable voltage source. Analysis of a NMOS gate-cross connected bridge rectifier is conducted to demonstrate relationship between device sizes and power conversion efficiency (PCE) of the rectifier. A rectifier with 38.54% PCE under normal working conditions is designed. Moreover, a stable voltage regulator with a temperature and voltage optimizing strategy including adoption of a combination resistor is developed, which is able to accommodate a large input range of 4 V to 12 V and be immune to temperature variations. Latch-up prevention and noise isolation methods in layout design are also presented. Designed with the HJTC 0.25 ?m process, this regulator achieves 0.04 mV/°C temperature rejection ratio (TRR) and 2.5 mV/V voltage rejection ratio (VRR). The RF powering circuit is also fabricated in the HJTC 0.25 ?m process. The area of the RF powering circuit is 0.23 × 0.24 mm². The RF powering circuit is successfully integrated with ISO/IEC 15693-compatible and ISO/IEC 14443-compatible RFID tag chips. PMID:25123466

Liu, Dongsheng; Wang, Rencai; Yao, Ke; Zou, Xuecheng; Guo, Liang

2014-01-01

167

Phased-array waveguide grating multi/demultiplexers and their applications in wavelength division multiplexing networks  

NASA Astrophysics Data System (ADS)

Wavelength Division Multiplexing (WDM) technology is emerging in response to the rapid increase of bandwidth and capacity requirements in communication systems and networks. In recent years, high performance and sophisticated photonic devices have been developed to meet WDM system requirements. The components based on phased-array waveguide gratings (PAWG) represent one of the key enabling technologies for WDM systems. This dissertation studied the principles, unique characteristics and system-related pertinent issues of PAWG-based WDM components. Modeling and design were performed to provide optimized PAWG device structures. High performance silica-on-silicon PAWG multi/demultiplexers were demonstrated with precise channel wavelength control, low insertion loss, low crosstalk and flat top passband. Full-wafer device performance and uniformity were studied statistically. A novel dual-channel-spacing PAWG multi/demultiplexer was designed and demonstrated to meet the current WDM system channel spacing requirements. A new device structure, a hybrid PAWG, was proposed for the first time and its feasibility was experimentally demonstrated. Furthermore, several applications of PAWG components were developed for WDM systems. A compact, paired PAWG with a new wavelength comb self-alignment function was proposed and demonstrated to provide standardized and precise channel wavelength alignment. The supervisory channel wavelength was incorporated in PAWG devices for future network management. A novel reflected-type wavelength add/drop multiplexer and wavelength cross-connect switch were proposed.

Lin, Wenhua

1997-11-01

168

Cryogenically stabilized superconductor in cable form for large currents and alternating field stresses  

SciTech Connect

A cryogenically stabilized superconductor in cable form comprises several superconducting elements which contain twisted conductor filaments of superconductive material which are embedded in a matrix material of predetermined electric conductivity and which are twisted with several stabilizing elements of thermally and electrically highly conductive material which is electrically normal conducting at the operating temperature of the superconductor and the electric conductivity of which at the operating temperature is substantially higher than that of the matrix material of the superconducting elements disposed parallel thereto. So this superconductor will be capable of carrying large currents, will have high cryogenic stability and at the same time have only small alternating field losses, pairs of stabilizing elements and superconducting elements form respective stabilized subconductors, the stabilizing elements of which are connected in an electrically conducting manner only at individual points disposed one behind the other in the lengthwise direction of the conductor to the respective superconducting elements; and the subconductors are twisted together and are electrically insulated from each other in such a manner that an electrically highly conducting cross connection of all subconductors is provided only after one or more respective twisting lay lengths.

Ries, G.

1983-10-11

169

"Stop Ne(c)king around": How interactomics contributes to functionally characterize Nek family kinases.  

PubMed

Aside from Polo and Aurora, a third but less studied kinase family involved in mitosis regulation is the never in mitosis-gene A (NIMA)-related kinases (Neks). The founding member of this family is the sole member NIMA of Aspergillus nidulans, which is crucial for the initiation of mitosis in that organism. All 11 human Neks have been functionally assigned to one of the three core functions established for this family in mammals: (1) centrioles/mitosis; (2) primary ciliary function/ciliopathies; and (3) DNA damage response (DDR). Recent findings, especially on Nek 1 and 8, showed however, that several Neks participate in parallel in at least two of these contexts: primary ciliary function and DDR. In the core section of this in-depth review, we report the current detailed functional knowledge on each of the 11 Neks. In the discussion, we return to the cross-connections among Neks and point out how our and other groups' functional and interactomics studies revealed that most Neks interact with protein partners associated with two if not all three of the functional contexts. We then raise the hypothesis that Neks may be the connecting regulatory elements that allow the cell to fine tune and synchronize the cellular events associated with these three core functions. The new and exciting findings on the Nek family open new perspectives and should allow the Neks to finally claim the attention they deserve in the field of kinases and cell cycle biology. PMID:24921005

Meirelles, Gabriela Vaz; Perez, Arina Marina; de Souza, Edmárcia Elisa; Basei, Fernanda Luisa; Papa, Priscila Ferreira; Melo Hanchuk, Talita Diniz; Cardoso, Vanessa Bomfim; Kobarg, Jörg

2014-05-26

170

Proxy-agent management platform for OXC managed objects  

NASA Astrophysics Data System (ADS)

In this paper, we present a Proxy-Agent Management Platform, which supports the managed objects of the Optical Cross-Connects (OXC). OXC is a sophisticated WDM network element (NE) that makes the WDM networks reconfigurable. It consists of several sub-NEs, such as 3R modules, Mux/Demux modules, transponder modules, optical switch fabric modules, and operation administration and maintenance processing modules. The OXC network element manager requests and gathers the managed information, alarms, and events from those sub-NEs in the OXC network element, and updates the Management Information Base (MIB) of the OXC managed object existed in the local or remote OXC network element management system. We propose an OXC network element manager with proxy-agent functions which could configure, control, and manage the sub-NEs via an unified access interface on the Common Object Request Broker Architecture (CORBA). The proxy-agent in the OXC network element management system offers its own MIB information to SNMP and/or CMIP manager. The proposed platform achieves high code reusability, provides unified access interfaces between sub-NEs and proxy-agent via ORB, and offers authentication and authorization. The proposed platform is verified on simulated testbed, and shows that managed objects can be added or droped easily to develop an intelligent OXC system.

Pahk, Soomyung; Joo, Seong-Soon; Nam, Hyun-Soon; Lee, Sang-Wha; Kim, Hae G.

2001-10-01

171

Applying genetic algorithm for the bandwidth allocation of ATM nets  

NASA Astrophysics Data System (ADS)

In this paper, we develop an improved optimization algorithm based on genetic algorithm (GA) approach for the bandwidth allocation of ATM networks. The ATM switches can be connected with multiples of DS3 trunks via digital cross connect systems (DCS). One of the advantages of DCS is its ability to reconfigure a customer network dynamically. We utilize this advantage in the design and dynamic reconfiguration of ATM networks. The problem is formulated as a network optimization problem where a congestion measure based on the average packet delay is minimized, subject to capacity constraints posed by the underlying facility trunks. We choose the traffic routing on the express pipes and the allocation of the bandwidth on these pipes as the variables in this problem. The previous GA algorithm is not practical because (1) the number of the traffic distribution patterns is huge, and (2) the values of offered traffic are continuous. A new representation of the chromosome, Net- Chro, and the reproduction operator are presented. We show that the previous algorithm cannot guarantee full usage of trunk capacities in the solutions it generates. We also discuss open-loop control to overcome the congestion caused by a trunk failure.

Park, Fransis Y.; Wong, Edward K.

1996-11-01

172

Broadband local service offerings using free-space optical links: a network business perspective  

NASA Astrophysics Data System (ADS)

12 This paper describes a promising optical wireless broadband technology that will provide low cost broadband services to the local access `last mile' market. This paper examines the application, advantages and limitations of utilizing Free Space Optical Communications (FSOC) systems for broadband access markets. The service markets that would fully utilize FSOC technologies include metropolitan areas, BLECs (multi- tenant dwellings/business apartments), campuses, industrial parks and `pole-to-hole' neighborhood deployments. This paper will identify weather dependent link availability as being the primary consideration in defining and selecting suitable locations for FSOC-based systems. Link availability in turn determines link range, type of service, and the need for transmission diversity. This paper will describe the implications of telecom `five nines' last-mile access availability and its effect on the transparent integration of FSOC technologies into the existing fiber optic networks. This paper will also describe propagation losses and link budget requirements for broadband FSOC-based local service. During adverse weather conditions, stand-alone, FSOC-based optical wireless links typically offer path lengths of less than 200 meters while still meeting the `five nines' availability criteria. This paper will also consider `availability limited' services. These services may prove to be attractive to customers who are willing to accept broadband service on an `as available basis'. The use of availability-enhancing transmission diversity and the use of intelligent `roof-top' routing and optical wireless cross connects between buildings will also be discussed.

Britz, David M.; Dodley, J. P.; Barnickel, D. J.

2001-02-01

173

An Iml3-Chl4 heterodimer links the core centromere to factors required for accurate chromosome segregation  

PubMed Central

Accurate segregation of genetic material in eukaryotes relies on the kinetochore, a multiprotein complex that connects centromeric DNA with microtubules. In yeast and humans, two proteins – Mif2/CENP-C and Chl4/CNEP-N – interact with specialized centromeric nucleosomes and establish distinct but cross-connecting axes of chromatin-microtubule linkage. Proteins recruited by Chl4/CENP-N include a subset that regulates chromsome transmission fidelity. We show that Chl4 and a conserved member of this subset, Iml3, both from S. cerevisiae, form a stable protein complex, which interacts with Mif2 and Sgo1. We have determined the structures of an Iml3 homodimer and an Iml3-Chl4 heterodimer, which suggest a mechanism for regulating assembly of this functional axis of the kinetochore. We propose that at the core centromere, the Chl4-Iml3 complex participates in recruiting factors, such as Sgo1, that influence sister chromatid cohesion and encourage sister kinetochore biorientation. PMID:24075991

Hinshaw, Stephen M.; Harrison, Stephen C.

2013-01-01

174

Human enteric viruses in groundwater from a confined bedrock aquifer  

USGS Publications Warehouse

Confined aquifers are overlain by low-permeability aquitards that are commonly assumed to protect underlying aquifers from microbial contaminants. However, empirical data on microbial contamination beneath aquitards is limited. This study determined the occurrence of human pathogenic viruses in well water from a deep sandstone aquifer confined by a regionally extensive shale aquitard. Three public water-supply wells were each sampled 10 times over 15 months. Samples were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) for several virus groups and by cell culture for infectious enteroviruses. Seven of 30 samples were positive by RT-PCR for enteroviruses; one of these was positive for infectious echovirus 18. The virus-positive samples were collected from two wells cased through the aquitard, indicating the viruses were present in the confined aquifer. Samples from the same wells showed atmospheric tritium, indicating water recharged within the past few decades. Hydrogeologic conditions support rapid porous media transport of viruses through the upper sandstone aquifer to the top of the aquitard 61 m below ground surface. Natural fractures in the shale aquitard are one possible virus transport pathway through the aquitard; however, windows, cross-connecting well bores, or imperfect grout seals along well casings also may be involved. Deep confined aquifers can be more vulnerable to contamination by human viruses than commonly believed. ?? 2007 American Chemical Society.

Borchardt, M.A.; Bradbury, K.R.; Gotkowitz, M.B.; Cherry, J.A.; Parker, B.L.

2007-01-01

175

Detection of fecal coliforms in water by using ((14)C)mannitol  

SciTech Connect

Interest in rapid bacterial detection methods for sanitary indicator bacteria in water prompted a study of the use of (14)C-mannitol (UL) to detect fecal coliforms (FC). A simple method was developed using m-FC broth, membrane filtration, and two-temperature incubation (35 C for 2 h, followed by 44.5 C for 2.5 h). Results indicated that FC numbers ranging from 1 x 10(1) to 2.1 x 10(5) cells could be detected in 4.5 h. Within sample reproducibility at all cell concentrations was good, but sample-to-sample reproducibility was variable. Comparisons between m-FC broth and m-FC broth modified by substituting 4-mannitol for lactose indicated that the standard m-FC broth was the better test medium. Results from experiments employing dimethyl sulfoxide (DMSO) to increase permeability of FC to (14)C-mannitol indicated no increase in (14)CO{sub 2} production due to DMSO. Detection of FC using this method may be useful for rapid analyses of potable water suspected of contamination due to distribution line breaks or cross-connections, or for quick surveys of potable source water quality.

Reasoner, D.J.; Geldreich, E.E.

1989-01-01

176

Planar waveguide based optical performance monitoring techniques and their applications in all-optical networks  

NASA Astrophysics Data System (ADS)

Over the past few years, DWDM has been widely adopted across the telecommunications industry to expand capacity in telecommunication infrastructure. The success of DWDM in increasing raw capacity on point-to-point fiber routes and the rapid growth of data communications accelerates the pace to all-optical networking. The goal of all- optical networking is to create a transparent optical layer that can easily manage the transport of signal entirely in the optical domain, reducing the need for processing and interpretation of signals, while increasing the reliability and restorability of high- bandwidth networks. However, the premise of transparent or all-optical networks requires the availability of tools to measure and control the smallest granular component of such networks-the wavelength channel, not only in the transportation system, but also in core switching segments. This dissertation studied the optical performance measuring tools for WDM networks, and categorized the optical performance monitoring into two layers: optical-physical-layer performance monitoring and optical-path-layer performance monitoring. With potential mass-production capability for future wide range application, planar waveguide technology is selected as the focus of this dissertation. In the optical-physical-layer, arrayed waveguide grating (AWG) based multi-channel wavelength, power and OSNR monitoring circuit were proposed. Modeling and design were performed to provide optimized performance. Multi- channel wavelength monitoring circuit was demonstrated with precise wavelength monitoring capability. Optical-path-layer performance layer monitoring becomes necessary while optical cross-connect (OXC) is implemented. Focusing on one type of OXC, this dissertation studied the possibility to build a low cost, robust and transparent monitoring scheme using similar planar waveguide technology which been used in optical- physical-layer monitoring. Furthermore, the applications of optical performance monitoring in all-optical networks were discussed, including system turn-up, dynamic gain spectrum flattening and power equalizing after OXC.

Zhong, Shan

177

Technologies for optical networking in Nx160-Gbit/s DWDM networks  

NASA Astrophysics Data System (ADS)

Future multi-terabit/s optical core networks require optical technologies capable of managing ultra-high bit rate OTDM/DWDM (optical time division multiplexing/dense wavelength division multiplexing) channels at 160 Gbit/s or higher bit rates. The key functionalities in ultra-high speed network nodes are all-optical wavelength conversion, 3R-regeneration and demultiplexing of OTDM signals. Advanced optical networking techniques (optical add-drop multiplexing and optical routing) are studied in simulations and their performance evaluated considering 160 Gbit/s OTDM/DWDM channels. Performance comparison results for both OADM (optical add-drop multiplexer) and OXC (optical cross-connect) node networking functionalities are shown considering different technologies: semiconductor-optical-amplifier-based symmetric Mach-Zehnder interferometers (SOA-MZI) for wavelength conversion, signal regeneration and demultiplexing, electroabsorption-modulator-based demultiplexers, and wavelength converters based on four-wave mixing in dispersion-shifted fiber. The simulation results show that the SOA-MZI is a promising technology for all-optical signal processing in network nodes mainly due to its signal regeneration capability. At ultra-high bit rates, however, the relaxation time of SOAs considerably limits the operation. A solution to mitigate this problem is to use a differential scheme at the input of the device. Error-free wavelength conversion, signal regeneration and demultiplexing of 160 Gbit/s OTDM signals employing a SOA-MZI with a differential scheme is demonstrated by means of simulations. Furthermore, the parameters of this architecture are optimized to obtain the best performance for each optical networking functionality in OADM and OXC network nodes.

Ramos, Francisco; Schulze, Karsten; Martinez, Jose Manuel; Marti, Javier; Llorente, Roberto; Clavero, Raquel

2003-08-01

178

The structure of the cuticular plate, an in vivo actin gel.  

PubMed

The cuticular plate is a network of actin filaments found in hair cells of the cochlea. In the alligator lizard, it consists of rootlets, emanating from the stereocilia, and of cross-connecting actin filaments that anchor these rootlets. In thin sections, this network displays striking patches of 650 +/- 110-A striae. By quantitative analyses of the images, the mystery of the striae can be explained. They are due in part to the rootlets which are sets of flat ribbons of actin filaments. The ribbons in each set are separated by approximately 650 A. Numerous whiskers 30 A in diameter extend from each ribbon's face, interconnecting adjacent ribbons. The nonrootlet filaments, except at the margins of the cell, occur primarily as single filaments. Like the ribbons, they are bristling with whiskers. The patches of striae are explained by ribbons and filaments held at a 650-A separation by the whiskers that project from them. A simple model for regions of bewhiskered filaments is a box crammed full of randomly oriented test-tube brushes. A thin slice through the box will show regions of dark lines or striae due to the wire backbones of the brushes separated from one another by the bristle length. Using the computer instead of test-tube brushes, we have been able to model quantitatively the filament distribution and pattern of striae seen in the cuticular plate of the lizard. The organization of actin filaments we have deduced from our simulations differs from that found in macrophages or in the terminal web of intestinal epithelial cells. PMID:2592408

DeRosier, D J; Tilney, L G

1989-12-01

179

WDM transmission upgrade using low-cost uncooled components  

NASA Astrophysics Data System (ADS)

Cost-effective short-haul but high-capacity optical transport systems are becoming increasingly important for metropolitan-area and access applications; examples are metro-feeders, inter- or intra-office links between routers and cross-connects, and storage-area networks. Transmission links of this kind are characterized by distances of 10 to 100 km and typically use directly modulated lasers providing a high output power at a low device cost. Due to the inherent wavelength drift of uncooled system components, full spectrum CWDM is defined for up to 16 or 18 channels on a coarse 20-nm wavelength grid between 1270 and 1610 nm. To meet the demand for the increase of transmission capacity in the metro and access domain, there are several potential strategies to remove the capacity limit of 16×2.5 Gb/s found in conventional CWDM systems while still retaining the cost-effectiveness and the modular "pay as you grow" philosophy of CWDM. In this paper, we provide an overview of recent progress in the field of CWDM upgrade techniques. CWDM architectures with increased per channel bit-rates and sub-band DWDM channel overlays are reviewed and experimental results are presented. The particular combination of CWDM with DWDM sub-bands and bit-rate upgrades is expected to deliver the highest capacity gain. However, we also show that the suitability of the system for higher bit-rates hinges on the following considerations: the availability of low-cost 10-Gb/s DMLs at the respective wavelengths, the link budget and the chromatic dispersion of the deployed system.

Thiele, Hans J.; Winzer, Peter J.

2005-11-01

180

Melatonin, the circadian multioscillator system and health: the need for detailed analyses of peripheral melatonin signaling.  

PubMed

Evidence is accumulating regarding the importance of circadian core oscillators, several associated factors, and melatonin signaling in the maintenance of health. Dysfunction of endogenous clocks, melatonin receptor polymorphisms, age- and disease-associated declines of melatonin likely contribute to numerous diseases including cancer, metabolic syndrome, diabetes type 2, hypertension, and several mood and cognitive disorders. Consequences of gene silencing, overexpression, gene polymorphisms, and deviant expression levels in diseases are summarized. The circadian system is a complex network of central and peripheral oscillators, some of them being relatively independent of the pacemaker, the suprachiasmatic nucleus. Actions of melatonin on peripheral oscillators are poorly understood. Various lines of evidence indicate that these clocks are also influenced or phase-reset by melatonin. This includes phase differences of core oscillator gene expression under impaired melatonin signaling, effects of melatonin and melatonin receptor knockouts on oscillator mRNAs or proteins. Cross-connections between melatonin signaling pathways and oscillator proteins, including associated factors, are discussed in this review. The high complexity of the multioscillator system comprises alternate or parallel oscillators based on orthologs and paralogs of the core components and a high number of associated factors with varying tissue-specific importance, which offers numerous possibilities for interactions with melatonin. It is an aim of this review to stimulate research on melatonin signaling in peripheral tissues. This should not be restricted to primary signal molecules but rather include various secondarily connected pathways and discriminate between direct effects of the pineal indoleamine at the target organ and others mediated by modulation of oscillators. PMID:22034907

Hardeland, Rüdiger; Madrid, Juan Antonio; Tan, Dun-Xian; Reiter, Russel J

2012-03-01

181

Eye Movement Abnormalities in Joubert Syndrome  

PubMed Central

Purpose Joubert syndrome is a genetic disorder characterized by hypoplasia of the midline cerebellum and deficiency of crossed connections between neural structures in the brain stem that control eye movements. The goal of the study was to quantify the eye movement abnormalities that occur in Joubert syndrome. Methods Eye movements were recorded in response to stationary stimuli and stimuli designed to elicit smooth pursuit, saccades, optokinetic nystagmus (OKN), vestibulo-ocular reflex (VOR), and vergence using video-oculography or Skalar search coils in 8 patients with Joubert syndrome. All patients underwent high-resolution magnetic resonance imaging (MRI). Results All patients had the highly characteristic molar tooth sign on brain MRI. Six patients had conjugate pendular (n = 4) or see-saw nystagmus (n = 2); gaze holding was stable in four patients. Smooth-pursuit gains were 0.28 to 1.19, 0.11 to 0.68, and 0.33 to 0.73 at peak stimulus velocities of 10, 20, and 30 deg/s in six patients; smooth pursuit could not be elicited in four patients. Saccade gains in five patients ranged from 0.35 to 0.91 and velocities ranged from 60.9 to 259.5 deg/s. Targeted saccades could not be elicited in five patients. Horizontal OKN gain was uniformly reduced across gratings drifted at velocities of 15, 30, and 45 deg/s. VOR gain was 0.8 or higher and phase appropriate in three of seven subjects; VOR gain was 0.3 or less and phase was indeterminate in four subjects. Conclusions The abnormalities in gaze-holding and eye movements are consistent with the distributed abnormalities of midline cerebellum and brain stem regions associated with Joubert syndrome. PMID:19443711

Weiss, Avery H.; Doherty, Dan; Parisi, Melissa; Shaw, Dennis; Glass, Ian; Phillips, James O.

2011-01-01

182

Microstructure and mechanical properties of synthetic brow-suspension materials.  

PubMed

Levator palpebrae superioris (LPS) is a muscle responsible for lifting the upper eyelid and its malfunction leads to a condition called "ptosis", resulting in disfigurement and visual impairment. Severe ptosis is generally treated with "brow-suspension" surgery, whereby the eyelid is cross-connected to the mobile tissues above the eyebrow using a cord-like material, either natural (e.g. fascia lata harvested from the patient) or a synthetic cord. Synthetic brow-suspension materials are widely used, due to not requiring the harvesting of fascia lata that can be associated with pain and donor-site complications. The mechanical properties of some commonly-used synthetic brow-suspension materials were investigated--namely, monofilament polypropylene (Prolene®), sheathed braided polyamide (Supramid Extra® II), silicone frontalis suspension rod (Visitec® Seiff frontalis suspension set), woven polyester (Mersilene® mesh), and expanded polytetrafluoroethylene (Ptose-Up). Each material underwent a single tensile loading to the failure of the material, at three different displacement rates (1, 750 and 1500 mm/min). All the materials exhibited elastic-plastic tensile stress-strain behaviour with considerable differences in elastic modulus, ultimate tensile strength, elastic limit and work of fracture. The results suggest that, as compared to other materials, the silicone brow-suspension rod (Visitec® SFSS) might be the most suitable, providing relatively long-lasting stability and desirable performance. These findings, together with other factors such as commercial availability, cost and clinical outcomes, will provide clinicians with a more rational basis for selection of brow-suspension materials. PMID:24411372

Kwon, Kyung-Ah; Shipley, Rebecca J; Edirisinghe, Mohan; Ezra, Daniel George; Rose, Geoffrey E; Rayment, Andrew W; Best, Serena M; Cameron, Ruth E

2014-02-01

183

Fluorescence as a potential monitoring tool for recycled water systems: a review.  

PubMed

A rapid, highly sensitive and selective detector is urgently required to detect contamination events in recycled water systems - for example, cross-connection events in dual reticulation pipes that recycle advanced treated sewage effluent - as existing technologies, including total organic carbon and conductivity monitoring, cannot always provide the sensitivity required. Fluorescence spectroscopy has been suggested as a potential monitoring tool given its high sensitivity and selectivity. A review of recent literature demonstrates that by monitoring the fluorescence of dissolved organic matter (DOM), the ratios of humic-like (Peak C) and protein-like (Peak T) fluorescence peaks can be used to identify trace sewage contamination in river waters and estuaries, a situation analogous to contamination detection in recycled water systems. Additionally, strong correlations have been shown between Peak T and biochemical oxygen demand (BOD) in rivers, which is indicative of water impacted by microbial activity and therefore of sewage impacted systems. Hence, this review concludes that the sensitive detection of contamination events in recycled water systems may be achieved by monitoring Peak T and/or Peak C fluorescence. However, in such systems, effluent is treated to a high standard resulting in much lower DOM concentrations and the impact of these advanced treatment processes on Peaks T and C fluorescence is largely unknown and requires investigation. This review has highlighted that further work is also required to determine (a) the stability and distinctiveness of recycled water fluorescence in relation to the treatment processes utilised, (b) the impact of matrix effects, particularly the impact of oxidation, (c) calibration issues for online monitoring, and (d) the advanced data analytical techniques required, if any, to improve detection of contamination events. PMID:19081598

Henderson, R K; Baker, A; Murphy, K R; Hambly, A; Stuetz, R M; Khan, S J

2009-03-01

184

The structure of the cuticular plate, an in vivo actin gel  

PubMed Central

The cuticular plate is a network of actin filaments found in hair cells of the cochlea. In the alligator lizard, it consists of rootlets, emanating from the stereocilia, and of cross-connecting actin filaments that anchor these rootlets. In thin sections, this network displays striking patches of 650 +/- 110-A striae. By quantitative analyses of the images, the mystery of the striae can be explained. They are due in part to the rootlets which are sets of flat ribbons of actin filaments. The ribbons in each set are separated by approximately 650 A. Numerous whiskers 30 A in diameter extend from each ribbon's face, interconnecting adjacent ribbons. The nonrootlet filaments, except at the margins of the cell, occur primarily as single filaments. Like the ribbons, they are bristling with whiskers. The patches of striae are explained by ribbons and filaments held at a 650-A separation by the whiskers that project from them. A simple model for regions of bewhiskered filaments is a box crammed full of randomly oriented test- tube brushes. A thin slice through the box will show regions of dark lines or striae due to the wire backbones of the brushes separated from one another by the bristle length. Using the computer instead of test- tube brushes, we have been able to model quantitatively the filament distribution and pattern of striae seen in the cuticular plate of the lizard. The organization of actin filaments we have deduced from our simulations differs from that found in macrophages or in the terminal web of intestinal epithelial cells. PMID:2592408

1989-01-01

185

Protein-like fluorescence intensity as a possible tool for determining river water quality  

NASA Astrophysics Data System (ADS)

The results of a comparison between chemical water quality determinants and river water fluorescence on the River Tyne, NE England, demonstrate that tryptophan-like fluorescence intensity shows statistically significant relationships between nitrate, phosphate, ammonia, biochemical oxygen demand (BOD) and dissolved oxygen. Tryptophan-like fluorescence intensity at the 280 nm excitation/350 nm emission wavelength fluorescence centre correlates with both phosphate (r = 0.80) and nitrate (r = 0.87), whereas tryptophan-like fluorescence intensity at the 220 nm excitation/350 nm emission wavelength centre correlates with BOD (r = 0.85), ammonia (r = 0.70) and dissolved oxygen (r = -0.65). The strongest correlations are between tryptophan-like fluorescence intensity and nitrate and phosphate, which in the Tyne catchment derive predominantly from point and diffuse source sewage inputs. The correlation between BOD and the tryptophan-like fluorescence intensity suggests that this fluorescence centre is related to the bioavailable or labile dissolved organic matter pool. The weakest correlations are observed between tryptophan-like fluorescence intensity and ammonia concentration and dissolved oxygen. The weaker correlation with ammonia is due to removal of the ammonia signal by wastewater treatment, and that with dissolved oxygen due to the natural aeration of the river such that this is not a good indicator of water quality. The observed correlations only hold true when treated sewage, sewerage overflows or cross connections, or agricultural organic pollutants dominate the water quality - this is not true for two sites where airport deicer (propylene glycol, which is non-fluorescent) or landfill leachate (which contains high concentrations of humic and fulvic-like fluorescent DOM) dominate the dissolved organic matter in the river. Mean annual tryptophan-like fluorescence intensity agrees well with the General Water Quality Assessment as determined by the England and Wales environmental regulators, the Environment Agency.

Baker, Andy; Inverarity, Roger

2004-10-01

186

Proline-rich protein-like PRPL1 controls elongation of root hairs in Arabidopsis thaliana.  

PubMed

The synthesis and composition of cell walls is dynamically adapted in response to many developmental and environmental signals. In this respect, cell wall proteins involved in controlling cell elongation are critical for cell development. Transcriptome analysis identified a gene in Arabidopsis thaliana, which was named proline-rich protein-like, AtPRPL1, based on sequence similarities from a phylogenetic analysis. The most resemblance was found to AtPRP1 and AtPRP3 from Arabidopsis, which are known to be involved in root hair growth and development. In A. thaliana four proline-rich cell wall protein genes, playing a role in building up the cross-connections between cell wall components, can be distinguished. AtPRPL1 is a small gene that in promoter::GUS (?-glucuronidase) analysis has high expression in trichoblast cells and in the collet. Chemical or mutational interference with root hair formation inhibited this expression. Altered expression levels in knock-out or overexpression lines interfered with normal root hair growth and etiolated hypocotyl development, but Fourier transform-infrared (FT-IR) analysis did not identify consistent changes in cell wall composition of root hairs and hypocotyl. Co-localization analysis of the AtPRPL1-green fluorescent protein (GFP) fusion protein and different red fluorescent protein (RFP)-labelled markers confirmed the presence of AtPRPL1-GFP in small vesicles moving over the endoplasmic reticulum. Together, these data indicate that the AtPRPL1 protein is involved in the cell's elongation process. How exactly this is achieved remains unclear at present. PMID:25147272

Boron, Agnieszka Karolina; Van Orden, Jürgen; Nektarios Markakis, Marios; Mouille, Grégory; Adriaensen, Dirk; Verbelen, Jean-Pierre; Höfte, Herman; Vissenberg, Kris

2014-10-01

187

Detection of fecal coliforms in water by using [14C]mannitol.  

PubMed Central

Interest in rapid bacterial detection methods for sanitary indicator bacteria in water prompted a study of the use of [U-14C]mannitol to detect fecal coliforms (FC). A simple method which used m-FC broth, membrane filtration, and two-temperature incubation (35 degrees C for 2 h followed by 44.5 degrees C for 2.5 h) was developed. [U-14C]mannitol was added to the medium, and the temperature was raised to 44.5 degrees C after 2 h at 35 degrees C. 14CO2 was collected as Ba14CO3 and assayed by liquid scintillation spectroscopy. Correlations were examined between FC cell numbers at the start of incubation (standard 24-h FC test) and Ba14CO3 counts per minute after 4.5 h. Results indicated that FC numbers ranging from 1 x 10(1) to 2.1 x 10(5) cells could be detected in 4.5 h. Within-sample reproducibility at all cell concentrations was good, but sample-to-sample reproducibility was variable. Comparisons between m-FC broth and m-FC broth modified by substituting D-mannitol for lactose indicated that the standard m-FC broth was the better test medium. Results from experiments in which dimethyl sulfoxide was used to increase permeability of FC to [U-14C]mannitol indicated no increase in 14CO2 production due to dimethyl sulfoxide. Detection of FC by this method may be useful for rapid estimation of FC levels in freshwater recreational areas, for estimating the quality of potable source water, and potentially for emergency testing of potable water, suspected of contamination due to distribution line breaks or cross-connections. PMID:2499258

Reasoner, D J; Geldreich, E E

1989-01-01

188

Effect of Emergency Argon on FCF Operational Incidents  

SciTech Connect

The following report presents analyses of operational incidents which are considered in the safety analysis of the FCF argon cell and the effect that the operability of the emergency argon system has on the course of these incidents. The purpose of this study is to determine if the emergency argon system makes a significant difference in ameliorating the course of these incidents. Six incidents were considered. The following three incidents were analyzed. These are: 1. Cooling failing on 2. Vacuum Pump Failing on 3. Argon Supplies Failing on. In the remaining three incidents, the emergency argon supply would have no effect on the course of these transients since it would not come on during these incidents. The transients are 1. Loss of Cooling 2. Loss of power (Differs from above by startup delay till the Diesel Generators come on.) 3. Cell rupture due to an earthquake or other cause. The analyses of the first three incidents are reported on in the next three sections. This report is issued realizing the control parameters used may not be optimum, and additional modeling must be done to model the inertia of refrigeration system, but the major conclusion concerning the need for the emergency argon system is still valid. The timing of some events may change with a more accurate model but the differences between the transients with and without emergency argon will remain the same. Some of the parameters assumed in the analyses are Makeup argon supply, 18 cfm, initiates when pressure is = -6 iwg., shuts off when pressure is = -3.1 iwg. 170,000 ft3 supply. Min 1/7th always available, can be cross connected to HFEF argon supply dewar. Emergency argon supply, 900 cfm, initiates when pressure is = -8 iwg. shuts off when pressure is =-4 iwg. reservoir 220 ft3, refilled when tank farm pressure reduces to 1050 psi which is about 110 ft3.

Charles Solbrig

2011-12-01

189

A complete design flow for silicon photonics  

NASA Astrophysics Data System (ADS)

Broad adoption of silicon photonics technology for photonic integrated circuits requires standardized design flows that are similar to what is available for analog and mixed signal electrical circuit design. We have developed a design flow that combines mature electronic design automation (EDA) software with optical simulation software. An essential component of any design flow, whether electrical or photonic, is the ability to accurately simulate largescale circuits. This is particularly important when the behavior of the circuit is not trivially related to the individual component performance. While this is clearly the case for electronic circuits consisting of hundreds to billions of transistors, it is already becoming important in photonic circuits such as WDM transmitters, where signal cross talk needs to be considered, as well as optical cross-connect switches. In addition, optical routing to connect different components requires the introduction of additional waveguide sections, waveguide bends, and waveguide crossings, which affect the overall circuit performance. Manufacturing variability can also have dramatic circuit-level consequences that need to be simulated. Circuit simulations must rely on compact models that can accurately represent the behavior of each component, and the compact model parameters must be extracted from physical level simulation and experimental results. We show how large scale circuits can be simulated in both the time and frequency domains, including the effects of bidirectional and, where appropriate, multimode and multichannel photonic waveguides. We also show how active, passive and nonlinear individual components such as grating couplers, waveguides, splitters, filters, electro-optical modulators and detectors can be simulated using a combination of electrical and optical algorithms, and good agreement with experimental results can be obtained. We then show how parameters, with inclusion of fabrication process variations, can be extracted for use in the circuit level simulations. Ultimately, we show how a multi-channel WDM transceiver can be created, from schematic design to tapeout, using key features of EDA design flows such as schematic driven layout, design rule checking and layout versus schematic.

Pond, James; Cone, Chris; Chrostowski, Lukas; Klein, Jackson; Flueckiger, Jonas; Liu, Amy; McGuire, Dylan; Wang, Xu

2014-05-01

190

Facilitation of stepping with epidural stimulation in spinal rats: role of sensory input.  

PubMed

We investigated the role of afferent information during recovery of coordinated rhythmic activity of the hindlimbs in rats with a complete spinal cord section (approximately T8) and unilateral deafferentation (T12-S2) to answer the following questions: (1) Can bilateral stepping be generated with only afferent projections intact on one side? (2) Can the sensory input from the non-deafferented side compensate for the loss of the afferent input from the deafferented side through the crossed connections within the lumbosacral spinal cord? (3) Which afferent projections to the spinal cord from the non-deafferented side predominantly mediate the effect of epidural stimulation to facilitate stepping? Recovery of stepping ability was tested under the facilitating influence of epidural stimulation at the S1 spinal segment, or epidural stimulation plus quipazine, a 5-HT agonist. All chronic spinal rats were able to generate stepping-like patterns on a moving treadmill on the non-deafferented, but not deafferented, side from 3 to 7 weeks after surgery when facilitated by epidural stimulation. Adaptation to the loss of unilateral afferent input was evident at 7 weeks after surgery, when some movements occurred on the deafferented side. Spinal-cord-evoked potentials were observed on both sides, although middle (monosynaptic) and late (long latency) responses were more prominent on the non-deafferented side. The afferent information arising from the non-deafferented side, however, eventually could mediate limited restoration of hindlimb movements on the deafferented side. These data suggest that facilitation of stepping with epidural stimulation is mediated primarily through ipsilateral afferents that project to the locomotor networks. PMID:18667609

Lavrov, Igor; Courtine, Grégoire; Dy, Christine J; van den Brand, Rubia; Fong, Andy J; Gerasimenko, Yuri; Zhong, Hui; Roy, Roland R; Edgerton, V Reggie

2008-07-30

191

Facilitation of Stepping with Epidural Stimulation in Spinal Rats: Role of Sensory Input  

PubMed Central

We investigated the role of afferent information during recovery of coordinated rhythmic activity of the hindlimbs in rats with a complete spinal cord section (~T8) and unilateral deafferentation (T12-S2) to answer the following questions: 1) Can bilateral stepping be generated with only afferent projections intact on one side? 2) Can the sensory input from the non-deafferented side compensate for the loss of the afferent input from the deafferented side through the crossed connections within the lumbosacral spinal cord? 3) Which afferent projections to the spinal cord from the non-deafferented side predominantly mediate the effect of epidural stimulation to facilitate stepping? Recovery of stepping ability was tested under the facilitating influence of epidural stimulation at the S1 spinal segment or epidural stimulation plus quipazine, a 5-HT agonist. All chronic spinal rats were able to generate stepping-like patterns on a moving treadmill on the non-deafferented, but not deafferented, side 3–7 weeks after surgery when facilitated by epidural stimulation. Adaptation to the loss of unilateral afferent input was evident at 7 weeks after surgery, when some movements occurred on the deafferented side. Spinal cord evoked potentials were observed on both sides, although middle (monosynaptic) and late (long-latency) responses were more prominent on the non-deafferented side. The afferent information arising from the non-deafferented side, however, eventually could mediate limited restoration of hindlimb movements on the deafferented side. These data suggest that facilitation of stepping with epidural stimulation is mediated primarily through ipsilateral afferents that project to the locomotor networks. PMID:18667609

Lavrov, Igor; Courtine, Grégoire; Dy, Christine J.; van den Brand, Rubia; Fong, Andy J.; Gerasimenko, Yuri; Zhong, Hui; Roy, Roland R.; Edgerton, V. Reggie

2010-01-01

192

Detection of fecal coliforms in water by using (/sup 14/C)mannitol  

SciTech Connect

Interest in rapid bacterial detection methods for sanitary indicator bacteria in water prompted a study of the use of (U-14C)mannitol to detect fecal coliforms (FC). A simple method which used m-FC broth, membrane filtration, and two-temperature incubation (35 degrees C for 2 h followed by 44.5 degrees C for 2.5 h) was developed. (U-14C)mannitol was added to the medium, and the temperature was raised to 44.5 degrees C after 2 h at 35 degrees C. 14CO2 was collected as Ba14CO3 and assayed by liquid scintillation spectroscopy. Correlations were examined between FC cell numbers at the start of incubation (standard 24-h FC test) and Ba14CO3 counts per minute after 4.5 h. Results indicated that FC numbers ranging from 1 x 10(1) to 2.1 x 10(5) cells could be detected in 4.5 h. Within-sample reproducibility at all cell concentrations was good, but sample-to-sample reproducibility was variable. Comparisons between m-FC broth and m-FC broth modified by substituting D-mannitol for lactose indicated that the standard m-FC broth was the better test medium. Results from experiments in which dimethyl sulfoxide was used to increase permeability of FC to (U-14C)mannitol indicated no increase in 14CO2 production due to dimethyl sulfoxide. Detection of FC by this method may be useful for rapid estimation of FC levels in freshwater recreational areas, for estimating the quality of potable source water, and potentially for emergency testing of potable water, suspected of contamination due to distribution line breaks or cross-connections.

Reasoner, D.J.; Geldreich, E.E.

1989-04-01

193

Single-phase Mn1-xZnxFe2O4(x = 0.2, 0.5, 0.8) hollow ceramic microspheres: One-step preparation and electromagnetic properties  

NASA Astrophysics Data System (ADS)

Single-phase Mn1-xZnxFe2O4 (x = 0.2, 0.5, 0.8) hollow ceramic microspheres (MnZn-HCMs) was one-step prepared using self-reactive quenching method. Material parameters of three MnZn-HCMs were studied by SEM and XRD, and electromagnetic properties were investigated by vibrating sample magnetometer and vector network analyzer. The results showed that the phase composition of three MnZn-HCMs presents single-phase, with particle size distribution of 20-60 ?m; when x was equal to 0.2 or 0.8, the surface of HCMs showed a large number of nano-lamellar crystal with crossing, connecting or laminating each other, and for 0.5, a large quantity of nano-isometric crystal was formed. Thanks to special surface structure and micron-particle size, three MnZn-HCMs exhibited superparamagnetic. With the content of Zn increases, the saturated magnetization (Ms) decreases first and then increases, meanwhile, the coercivity (Hc) decreases gradually. In the 0.1-18 GHz range, due to nano-lamellar structure could enhance the interfacial polarization and space charge polarization, Mn0.8Zn0.2Fe2O4 HCMs and Mn0.2Zn0.8Fe2O4 HCMs have higher real part of permittivity (?') value than Mn0.5Zn0.5Fe2O4 HCMs. Owing to higher conductivity, the value of imaginary part of permittivity (??) of Mn0.5Zn0.5Fe2O4 HCMs was the highest in 0.1-0.8 GHz range, however, with the frequency increases, the ?? of Mn0.8Zn0.2Fe2O4 HCMs and Mn0.2Zn0.8Fe2O4 HCMs increased significantly resulting from orientation polarization and interfacial polarization, which was greater than Mn0.5Zn0.5Fe2O4 HCMs. Due to the higher Ms, the value of imaginary part of permeability (??) of Mn0.2Zn0.8Fe2O4 HCMs and Mn0.8Zn0.2Fe2O4 HCMs was greater than Mn0.5Zn0.5Fe2O4 HCMs. Moreover, the ??-f curve reveals a broad resonance peak of Mn0.8Zn0.2Fe2O4 HCMs ranging from 0.1 to 8 GHz, which maybe relate to its thick nano-lamellar crystal.

Hongfei, Lou; Jianjiang, Wang; Baocai, Xu; Guanhui, Liang; Zhiguang, Li; Yongshen, Hou; Guoshun, Wan; Haitao, Gao; Liang, Yu

2014-11-01

194

Fiber optic DTS in sealed and heated boreholes for active groundwater flow characterization  

NASA Astrophysics Data System (ADS)

In recent years, advances in technology have allowed temperature profiling to evolve to offer new insight into fractured rock hydrogeology. Temperature profiles in open boreholes within fractured rock have long been used to identify and characterize flow in the rock formation and/or in the borehole. An advance in temperature logging makes use of precision temperature profiles collected using wireline trolling methods in a heated borehole to identify fractures with active groundwater flow by creating a thermal disequilibrium and monitoring the temperature response. A second development is based on collecting wireline temperature profiles within a sealed borehole to eliminate short circuiting effects caused by the open borehole conduit. The borehole is temporarily sealed with a flexible impervious fabric liner so that the water column in the borehole is static and cross-connection is eliminated. Though highly precise temperature and spatial measurements are possible using these techniques, the temporal resolution is limited by the rate at which the wireline probe can be raised and lowered in the borehole. There is a need to measure temperature profiles continuously over time to characterize transient processes. Fibre optic distributed temperature sensing (DTS) is a technique that allows for collecting temperature profiles continuously. This tool was advanced by the oil and gas industry for collecting temperature data in multi kilometer deep boreholes over relatively coarse measurement scales. In contrast, very fine spatial and temperature resolutions are needed for freshwater contaminant fractured rock hydrogeology where the scale of interest is much more acute. Recent advances in the spatial, temperature, and temporal resolution of DTS systems allow this technology to be adapted well to the shallow subsurface environment. This project demonstrates the first application of DTS used in conjunction with flexible borehole liners in a heated borehole environment. The integration of DTS, active heating, and lined boreholes was tested in the context of fractured rock site characterization. DTS heat pulse tests were carried out in two boreholes located at a well characterized research site in Guelph, ON, Canada. The capabilities for long-term and high temporal resolution site monitoring and characterization from the developed methods were assessed. The results of this technique are promising and indicate evidence for identifying active groundwater flow. Advancements to the DTS heat pulse method are possible to offer further improved insight into natural groundwater flow systems.

Coleman, Thomas; Parker, Beth; Cherry, John; Mondanos, Michael

2013-04-01

195

A Multiple-Tracer Approach for Identifying Sewage Sources to an Urban Stream System  

USGS Publications Warehouse

The presence of human-derived fecal coliform bacteria (sewage) in streams and rivers is recognized as a human health hazard. The source of these human-derived bacteria, however, is often difficult to identify and eliminate, because sewage can be delivered to streams through a variety of mechanisms, such as leaking sanitary sewers or private lateral lines, cross-connected pipes, straight pipes, sewer-line overflows, illicit dumping of septic waste, and vagrancy. A multiple-tracer study was conducted to identify site-specific sources of sewage in Accotink Creek, an urban stream in Fairfax County, Virginia, that is listed on the Commonwealth's priority list of impaired streams for violations of the fecal coliform bacteria standard. Beyond developing this multiple-tracer approach for locating sources of sewage inputs to Accotink Creek, the second objective of the study was to demonstrate how the multiple-tracer approach can be applied to other streams affected by sewage sources. The tracers used in this study were separated into indicator tracers, which are relatively simple and inexpensive to apply, and confirmatory tracers, which are relatively difficult and expensive to analyze. Indicator tracers include fecal coliform bacteria, surfactants, boron, chloride, chloride/bromide ratio, specific conductance, dissolved oxygen, turbidity, and water temperature. Confirmatory tracers include 13 organic compounds that are associated with human waste, including caffeine, cotinine, triclosan, a number of detergent metabolites, several fragrances, and several plasticizers. To identify sources of sewage to Accotink Creek, a detailed investigation of the Accotink Creek main channel, tributaries, and flowing storm drains was undertaken from 2001 to 2004. Sampling was conducted in a series of eight synoptic sampling events, each of which began at the most downstream site and extended upstream through the watershed and into the headwaters of each tributary. Using the synoptic sampling approach, 149 sites were sampled at least one time for indicator tracers; 52 of these sites also were sampled for confirmatory tracers at least one time. Through the analysis of multiple-tracer levels in the synoptic samples, three major sewage sources to the Accotink Creek stream network were identified, and several other minor sewage sources to the Accotink Creek system likely deserve additional investigation. Near the end of the synoptic sampling activities, three additional sampling methods were used to gain better understanding of the potential for sewage sources to the watershed. These additional sampling methods included optical brightener monitoring, intensive stream sampling using automated samplers, and additional sampling of several storm-drain networks. The samples obtained by these methods provided further understanding of possible sewage sources to the streams and a better understanding of the variability in the tracer concentrations at a given sampling site. Collectively, these additional sampling methods were a valuable complement to the synoptic sampling approach that was used for the bulk of this study. The study results provide an approach for local authorities to use in applying a relatively simple and inexpensive collection of tracers to locate sewage sources to streams. Although this multiple-tracer approach is effective in detecting sewage sources to streams, additional research is needed to better detect extremely low-volume sewage sources and better enable local authorities to identify the specific sources of the sewage once it is detected in a stream reach.

Hyer, Kenneth Edward

2007-01-01

196

Detection of Human Sewage in Urban Stormwater Using DNA Based Methods and Stable Isotope Analysis  

NASA Astrophysics Data System (ADS)

Urban stormwater is a major source of fecal indicator bacteria in the Milwaukee River Basin, a major watershed draining to Lake Michigan. Much of the watershed is in highly urbanized areas and Escherichia coli (E. coli) levels have been found to be 20,000 CFU per 100 ml in the estuary leading to Lake Michigan. Aging infrastructure and illicit cross connections may allow sewage to infiltrate the stormwater system and could contribute both fecal indicator bacteria and human pathogens to these waters. We conducted extensive sampling of stormwater outfalls in the lower reaches of three major tributaries. Three outfalls along the heavily urbanized Kinnickinnick (KK) were found to have geometric mean E. coli and enterococci levels of 16,200 and 28,700 CFU/100 ml, respectively. Four outfalls along the Menomonee River, draining both suburban and urban areas, had geometric mean E. coli and enterococci levels of 14,700 and 12,800 CFU/100 ml, respectively. These seven outfalls had more than 60% of the samples positive for human specific Bacteroides genetic marker (n=46), suggesting the presence of human sources. In addition, two outfalls on Lincoln Creek, a smaller tributary of the Milwaukee River, had geometric mean E. coli and enterococci levels of 16,700 and 14,900 CFU per 100 ml, respectively. The human specific Bacteroides marker was positive in nearly 90% of the samples (n=24). Subsequent virus testing at one of these outfalls confirmed human pathogens were present with adenovirus detected at 1.3 x 10E3 genomic equivalents (ge)/L, enterovirus at 1.9 x 10E4 ge/L and G1 norovirus at 1.5 x 10E3 ge/L; these values are similar to concentrations found in sewage. Stable isotope studies were conducted in the three tributaries to investigate the relationship between delta C and delta N isotopic composition and microbiological quality of this urban freshwater system. This work is based on the premise that the organic matter of the stormwater will have a stable isotopic signature related to the mixed organic matter sources in polluted stormwater runoff, and that this signal will distinct from untreated sanitary sewage. Stable isotope signatures of stormwater and untreated sewage were determined and compared with the rivers. Isotopic values of stormwater was delta 15N = 1.1 ± 2 %; delta 13C = -25.5 ± 3 % and sewage was delta 15N = -1.9 ± 0.2 %; delta 13C = -23.6 ± 0.3. Suspended particular organic matter (SPOM) of Milwaukee River showed depleted delta 13C (-28.6 ± 1.6 %) and enriched delta 15N (7.7 ± 1.9 %) values. SPOM of the KK River exhibited the most depleted delta 15N (0.2 ± 1.6 %) and enriched delta 13C (-24.8 ± 1.8 %) isotopic values. Menomonee River SPOM showed intermediate isotopic values. The delta 13C values of each river and the estuary enriched significantly throughout the summer storm periods. The isotope signals in the KK and Menomonee were indicative of stormwater runoff and sewage contamination. These results suggest that unrecognized sewage inputs are chronically present and may be delivered through urban stormwater systems. DNA based methods combined with isotope analysis may provide a useful tool for urban watershed assessments and to identify sewage inputs. Delineating the relative contribution of stormwater and sewage to overall degraded water quality might give the first indication of the impact of these sources on the Michigan Lake waters.

McLellan, S. L.; Malet, N.; Sauer, E.; Mueller-Spitz, S.; Borchardt, M.

2008-12-01

197

Evaluation of long-term water-level declines in basalt aquifers near Mosier, Oregon  

USGS Publications Warehouse

The Mosier area lies along the Columbia River in northwestern Wasco County between the cities of Hood River and The Dalles, Oregon. Major water uses in the area are irrigation, municipal supply for the city of Mosier, and domestic supply for rural residents. The primary source of water is groundwater from the Columbia River Basalt Group (CRBG) aquifers that underlie the area. Concerns regarding this supply of water arose in the mid-1970s, when groundwater levels in the orchard tract area began to steadily decline. In the 1980s, the Oregon Water Resources Department (OWRD) conducted a study of the aquifer system, which resulted in delineation of an administrative area where parts of the Pomona and Priest Rapids aquifers were withdrawn from further appropriations for any use other than domestic supply. Despite this action, water levels continued to drop at approximately the same, nearly constant annual rate of about 4 feet per year, resulting in a current total decline of between 150 and 200 feet in many wells with continued downward trends. In 2005, the Mosier Watershed Council and the Wasco Soil and Water Conservation District began a cooperative investigation of the groundwater system with the U.S. Geological Survey. The objectives of the study were to advance the scientific understanding of the hydrology of the basin, to assess the sustainability of the water supply, to evaluate the causes of persistent groundwater-level declines, and to evaluate potential management strategies. An additional U.S. Geological Survey objective was to advance the understanding of CRBG aquifers, which are the primary source of water across a large part of Oregon, Washington, and Idaho. In many areas, significant groundwater level declines have resulted as these aquifers were heavily developed for agricultural, municipal, and domestic water supplies. Three major factors were identified as possible contributors to the water-level declines in the study area: (1) pumping at rates that are not sustainable, (2) well construction practices that have resulted in leakage from aquifers into springs and streams, and (3) reduction in aquifer recharge resulting from long-term climate variations. Historical well construction practices, specifically open, unlined, uncased boreholes that result in cross-connecting (or commingling) multiple aquifers, allow water to flow between these aquifers. Water flowing along the path of least resistance, through commingled boreholes, allows the drainage of aquifers that previously stored water more efficiently. The study area is in the eastern foothills of the Cascade Range in north central Oregon in a transitional zone between the High Cascades to the west and the Columbia Plateau to the east. The 78-square mile (mi2) area is defined by the drainages of three streams - Mosier Creek (51.8 mi2), Rock Creek (13.9 mi2), and Rowena Creek (6.9 mi2) - plus a small area that drains directly to the Columbia River.The three major components of the study are: (1) a 2-year intensive data collection period to augment previous streamflow and groundwater-level measurements, (2) precipitation-runoff modeling of the watersheds to determine the amount of recharge to the aquifer system, and (3) groundwater-flow modeling and analysis to evaluate the cause of groundwater-level declines and to evaluate possible water resource management strategies. Data collection included the following: 1. Water-level measurements were made in 37 wells. Bi-monthly or quarterly measurements were made in 30 wells, and continuous water-level monitoring instruments were installed in 7 wells. The measurements principally were made to capture the seasonal patterns in the groundwater system, and to augment the available long-term record. 2. Groundwater pumping was measured, reported, or estimated from irrigation, municipal and domestic wells. Flowmeters were installed on 74 percent of all high-capacity irrigation wells in the study area. 3. Borehole geophysical data were collected from a known commingling well. These data measured geologic properties and vertic

Burns, Erick R.; Morgan, David S.; Lee, Karl K.; Haynes, Jonathan V.; Conlon, Terrence D.

2012-01-01