These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Electrodynamic forces of the cross-connected figure-eight null-flux coil suspension system  

SciTech Connect

This paper analyzes the cross-connected figure-eight null-flux coil suspension system for maglev vehicles on the basis of dynamic circuit theory. The equivalent circuits and general magnetic force expressions for the system are developed. Simple analytical formulas for the magnetic force partitions on the basis of harmonic approximation are presented, and numerical results are also included.

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

1993-01-01

2

Electrodynamic forces of the cross-connected figure-eight null-flux coil suspension system  

SciTech Connect

This paper analyzes the cross-connected figure-eight null-flux coil suspension system for maglev vehicles on the basis of dynamic circuit theory. The equivalent circuits and general magnetic force expressions for the system are developed. Simple analytical formulas for the magnetic force partitions on the basis of harmonic approximation are presented, and numerical results are also included.

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

1993-06-01

3

Computer modeling and experimental verification of figure-eight-shaped null-flux coil suspension system  

SciTech Connect

This report discusses the computer modeling and experimental verification of the magnetic forces associated with a figure-eight-shaped null-flux coil suspension system. A set of computer codes called COILGDWY, were developed on the basis of the dynamic circuit model and verified by means of a laboratory model. The experimental verification was conducted with a rotating PVC drum, the surface of which held various types of figure-eight-shaped null-flux coils that interacted with a stationary permanent magnet. The transient and dynamic magnetic forces between the stationary magnet and the rotating conducting coils were measured and compared with results obtained from the computer model. Good agreement between the experimental results and computer simulations was obtained. The computer model can also be used to calculate magnetic forces in a large-scale magnetic-levitation system.

He, J.L.; Mulcahey, T.M.; Rote, D.M.; Kelly, T.

1994-12-01

4

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

5

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

6

Forces on a magnet moving past figure-eight coils  

SciTech Connect

For the first time, the lift, drag, and guidance forces acting on a permanent magnet are measured as the magnet passes over different arrays of figure-eight (null-flux) coils. The experimental results are in good agreement with the predictions of dynamic circuit theory, which is used to explain more optimal coil arrays.

Mulcahy, T.H.; He, Jianliang; Rote, D.M. [Argonne National Lab., IL (United States); Rossing, T.D. [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Physics

1993-03-01

7

Forces on a magnet moving past figure-eight coils  

SciTech Connect

For the first time, the lift, drag, and guidance forces acting on a permanent magnet are measured as the magnet passes over different arrays of figure-eight (null-flux) coils. The experimental results are in good agreement with the predictions of dynamic circuit theory, which is used to explain more optimal coil arrays.

Mulcahy, T.H.; He, Jianliang; Rote, D.M. (Argonne National Lab., IL (United States)); Rossing, T.D. (Northern Illinois Univ., De Kalb, IL (United States). Dept. of Physics)

1993-01-01

8

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

9

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

Federal Register 2010, 2011, 2012, 2013

...of the fireworks display for a private wedding. This action is necessary to protect...fireworks display in support of a private wedding over the waters of the Figure Eight Causeway...not require an assessment of potential costs and benefits under section...

2013-05-02

10

BROWNIAN MOTION ON THE FIGURE EIGHT ILIE GRIGORESCU1  

E-print Network

BROWNIAN MOTION ON THE FIGURE EIGHT ILIE GRIGORESCU1 AND MIN KANG2 Abstract. In an interval containing the origin we study a Brownian motion returning to zero as soon as it reaches the boundary Classification. Primary: 60K35; Secondary: 60J50, 35K15 . Key words and phrases. Absorbing Brownian motion

Grigorescu, Ilie

11

Homochiral and meso figure eight knots and a Solomon link.  

PubMed

A homochiral naphthalenediimide-based building block forms in water a disulfide library of macrocycles containing topological isomers. We attempted to identify each of these isomers, and explored the mechanisms leading to their formation. The two most abundant species of the library were assigned as a topologically chiral Solomon link (60% of the library, as measured by high-performance liquid chromatography (HPLC)) and a topologically achiral figure eight knot (18% by HPLC), competing products with formally different geometries but remarkably similar 4-fold symmetries. In contrast, a racemic mixture of building blocks gives the near-quantitative formation of another new and more stable structure, assigned as a meso figure eight knot. Taken together, these results seem to uncover a correlation between the point chirality of the building block used and the topological chirality of the major structure formed. These and the earlier discovery of a trefoil knot also suggest that the number of rigid components in the building block may translate into corresponding knot symmetry and could set the basis of a new strategy for constructing complex topologies. PMID:24831779

Ponnuswamy, Nandhini; Cougnon, Fabien B L; Panto?, G Dan; Sanders, Jeremy K M

2014-06-11

12

High repetition rate, mode locked, figure eight laser with extracavity feedback  

NASA Astrophysics Data System (ADS)

The present invention relates to fiber laser generators of soliton pulses and more particularly to a figure eight fiber laser with extracavity feedback to obtain pulse shortening, initiation of mode locking, and repetition rate control.

Dennis, Michael L.; Duling, Irl N., III

1993-09-01

13

DEVELOPMENT OF LOCOMOTOR ACTIVITY OF RAT PUPS IN FIGURE-EIGHT MAZES  

EPA Science Inventory

In a series of four experiments, social and experiential factors that influence the development of motor activity in rat pups were examined. Motor activity was monitored from postnatal days 13 to 21 as photocell interruptions in figure-eight mazes and comparisons were made betwee...

14

Electromagnetic characteristics of eccentric figure-eight coils for transcranial magnetic stimulation: A numerical study  

NASA Astrophysics Data System (ADS)

Repetitive transcranial magnetic stimulation (rTMS) is effective for treatment of several neurological and psychiatric diseases. We proposed an eccentric figure-eight coil, which induces strong eddy currents in the target brain tissue. In this study, numerical analyses were carried out to obtain magnetic field distribution of the eccentric figure-eight coil and eddy current in the brain. The analyses were performed with various coil design parameters, such as the outer and inner diameters and number of turns, to investigate the influence of these parameters on the coil characteristics. Increases in the inner diameter, outer diameter, and number of turns caused increases in the maximum eddy current densities. Coil inductance, working voltage, and heat generation also became higher with the increases in these design parameters. In order to develop a compact stimulator system for use at home, we need to obtain strong eddy current density, keeping the working voltage as low as possible. Our results show that it is effective to enlarge the outer diameter.

Kato, Takuya; Sekino, Masaki; Matsuzaki, Taiga; Nishikawa, Atsushi; Saitoh, Youichi; Ohsaki, Hiroyuki

2012-04-01

15

Computer model simulation of null-flux magnetic suspension and guidance  

SciTech Connect

This paper discusses the magnetic force computations in a null-flux suspension system using dynamic circuit theory. A computer simulation model that can be used to compute magnetic forces and predict the system performance is developed on the basis of dynamic circuit theory. Numerical examples are presented to demonstrate the application of the model. The performance of the null-flux suspension system is simulated and discussed. 8 refs.

He, Jianliang; Rote, D.M.

1992-06-01

16

Computer model simulation of null-flux magnetic suspension and guidance  

SciTech Connect

This paper discusses the magnetic force computations in a null-flux suspension system using dynamic circuit theory. A computer simulation model that can be used to compute magnetic forces and predict the system performance is developed on the basis of dynamic circuit theory. Numerical examples are presented to demonstrate the application of the model. The performance of the null-flux suspension system is simulated and discussed. 8 refs.

He, Jianliang; Rote, D.M.

1992-01-01

17

Design approaches and parameters for magnetically levitated transport systems. [Null flux suspension (Maglev)  

SciTech Connect

Mechanically levitated transport system approaches are assessed with regard to thrust power needs, track cost, suspension stability, and safety. The null flux suspension appears as the favored approach, having the least thrust power requirements, highest stability, and lowest amount of track material. Various null flux configurations are described together with their operating parameters. The Linear Synchronous Motor (LSM) propulsion system is also described for propelling the suspended vehicles. Cryogenics and superconductivity aspects are discussed and the effect of high T/sub c/ superconductors evaluated. 13 refs., 16 figs., 2 tabs.

Danby, G.T.; Powell, J.R.

1988-01-01

18

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

19

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

20

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

21

Supercontinuum generation in a standard fiber pumped by noise-like pulses from a figure-eight fiber laser  

NASA Astrophysics Data System (ADS)

We report the experimental study of broadband spectrum generation in a piece of standard fiber (SMF-28) using as the pump a train of noise-like pulses, or sub-nanosecond packets of sub-ps pulses with randomly varying amplitudes. The pulses are generated by an erbium-doped figure-eight fiber laser, and present a wide (˜50 nm) optical spectrum, which represents a significant advantage to seed the generation of new frequencies. Another advantage of the pulses is their relatively large energy, as they are made up of a large number of ultrashort pulses. After amplification with an Erbium Doped Fiber Amplifier (EDFA), the pulses were injected in a 0.75 km length of SMF-28 fiber. We obtained experimentally at the end of the fiber an out-put signal spectrum extending from 1530 nm to at least 1750 nm (the upper limit of the spectrum analyzer) for pump pulses with an average power of 20.4 mW, corresponding to a few kilowatts peak power. The spectral broadening is due to Raman self-frequency shift (SFS). It is noteworthy that the spectrum of the newly created frequencies was extremely uniform over the range of measurement. Considering that the Raman shift is directly related to the pump pulse duration, spectral flatness is a direct consequence of the random distribution of amplitudes and durations of the pulses in the packet. Finally, the results show the capabilities of noise-like pulses from a fiber laser for applications in supercontinuum generation based on nonlinear phenomena such as Raman SFS.

Hernandez-Garcia, J. C.; Pottiez, O.; Estudillo-Ayala, J. M.

2011-10-01

22

12 GHz passive harmonic mode-locking in a 1.06 ?m semiconductor optical amplifier-based fiber laser with figure-eight cavity configuration.  

PubMed

We report the generation of passively harmonic mode-locked pulses using a 1.06 ?m semiconductor optical amplifier (SOA) in a figure-eight laser configuration operated in the all-normal-dispersion regime. Different orders of harmonic mode-locking can be obtained from 30 MHz to 12.02 GHz by changing the injection current of the SOA from 80 to 660 mA together with the adjustment of polarization controllers. The highest pulse repetition rate increases almost linearly with the SOA current. As SOA current is set to 660 mA, we obtain the intracavity power of 46 mW at the highest repetition rate of 12.02 GHz, corresponding to the 1202th harmonic of the fundamental mode-locking frequency. To our best knowledge, this is the lowest intracavity power to generate the highest repetition rate with a passively mode-locked laser in the all-normal-dispersion regime. PMID:23503235

Chen, Hou-Ren; Lin, Kuei-Huei; Tsai, Chih-Ya; Wu, Hsiao-Hua; Wu, Chih-Hsuan; Chen, Chieh-Han; Chi, Yu-Chieh; Lin, Gong-Ru; Hsieh, Wen-Feng

2013-03-15

23

Experimental study to improve the focalization of a figure-eight coil of rTMS by using a highly conductive and highly permeable medium.  

PubMed

A method to improve the focalization of the repetitive transcranial magnetic stimulation figure-eight coil in a magnetic stimulation is presented in this paper. For the purpose of reducing the half width of the distribution curve, while improving the ratio of positive to negative electric field, a shield plate with a window and a magnetic conductor were adopted. The shield plate, which was made of highly conductive copper, focused the magnetic field into a smaller area. The magnetic inductor, which was made of highly permeable soft magnetic ferrite, strengthened the magnetic field. A group of experiments was conducted to validate the focalizing effect. Experimental results showed that the negative peak and the half width of the distribution curve reduced by using the shield plate and the magnetic conductor. Especially for to the Magstim 70 mm double coil, when the shield window was 30 × 60 mm, the ratio of positive to negative electric field could be increased 109%, while the half width of the distribution curve could be reduced about 55%. PMID:22531823

Zhang, Shunqi; Yin, Tao; Liu, Zhipeng; Li, Ying; Jin, Jingna; Ma, Ren

2013-05-01

24

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

25

Study of Japanese electrodynamic-suspension maglev systems  

SciTech Connect

This report presents the results of a study of the Japanese MLU magnetic-levitation (maglev) system. The development of the MLU system is reviewed, and the dynamic circuit model then is introduced and applied to the figure-eight-shaped null-flux coil suspension system. Three different types of figure-eight-shaped null-flux suspension systems are discussed in detail: (1) the figure-eight-shaped null-flux coil suspension system without cross-connection; (2) the combined suspension and guidance system; and (3) the combined propulsion, levitation, and guidance system. The electrodynamic-suspension maglev systems developed in Japan seem to be very promising and could result in a commercial application in the near future.

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

1994-04-01

26

Dual-keel electrodynamic maglev system  

SciTech Connect

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

1995-12-31

27

Optical path technologies: a comparison among different cross-connect architectures  

Microsoft Academic Search

The introduction of optical technology in the path layer of the transport network is expected to allow scalable and modular networks to be realized. In this paper, different optical cross-connect architectures, based either on space division or wavelength division switching, are analyzed. A comparative investigation is accomplished considering three issues of primary importance: cross-connect modularity, complexity, and transmission performance. In

Eugenio Iannone; Roberto Sabella

1996-01-01

28

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

29

Characterization of pre-cross-connected trails for optical mesh network protection  

NASA Astrophysics Data System (ADS)

Recently there has been interest in so-called pre-cross-connected protection architectures for optical networks. The main benefit of pre-cross-connected protection is that multiple cross-connection actions are not required in real time at the time of failure. This addresses the practical concern that, in a transparent optical network, one may not be able to make a series of protection path-forming cross-connections in a succession of optical spans with certainty that the resultant end-to-end connection has optical path integrity. Self-healing rings, p-cycles, and preconnected linear segment protection are examples of prior methods that employ prefailure cross-connection of protection capacity but are not end-to-end path-oriented. More recent work has proposed pre-cross-connected trails (PXTs), which are fully preconnected linear path-protecting structures. The same work also provided an online heuristic algorithm for generating PXT network designs. However, important and interesting properties such as length and cyclicity of the PXT structures remained to be characterized. We delve further into PXT network design, attempting to validate claims made previously and to understand the structural and operational properties of PXTs. This involves reimplementation of and experimentation with the above heuristic. Results show that heuristically obtained designs frequently contain PXTs of great total length and high complexity, as well as other PXTs that are equivalent to 1+1 automatic protection switching (APS) arrangements. Through diagramming and statistical analysis of PXT characteristics we give the first intuitive appreciation of the structure and function of PXTs.

Grue, Aden; Grover, Wayne D.

2006-06-01

30

On a Quest for Good Process Models: The Cross-Connectivity Metric  

E-print Network

- tem development, training, process enactment, costing and budgeting. In many business applications issues [30]. It is a considerable problem for these application areas of process modeling in practiceOn a Quest for Good Process Models: The Cross-Connectivity Metric Irene Vanderfeesten1 , Hajo A

van der Aalst, Wil

31

Proposed optical cross connect using a planar arrangement of beam steerers  

Microsoft Academic Search

We propose a design for a strict-sense nonblocking N×N spatial optical cross connect that employs planar lightwave beam steerers. The beam steerers allow for a modular design without requiring two-dimensional chip-to-chip waveguide interconnections. The modular design and the fact that the number of electrical leads scales as N log N in turn allows the possibility of constructing large, robust, solid-state

C. R. Doerr; C. Dragone

1999-01-01

32

Design and performance of an optical path cross-connect system based on wavelength path concept  

Microsoft Academic Search

This paper describes the system design and performance of an optical path cross-connect (OPXC) system based on wavelength path concept. The (OPXC) is designed to offer 16 sets of input and output fiber ports with each fiber transporting eight multiwavelength signals for optical paths. Each optical path has a capacity of 2.5 Gb\\/s. Consequently, the total system throughput is 8×16×2.5=320

Masafumi Koga; Yoshiyuki Hamazumi; Atsushi Watanabe; Satoru Okamoto; Hitoshi Obara; Ken-Ichi Sato; Masayuki Okuno; Senichi Suzuki

1996-01-01

33

On the expandability of free-space micromachined optical cross connects  

Microsoft Academic Search

Free-space micromachined optical-switching technology has emerged as a promising candidate for the large-scale optical cross connects that are needed in next-generation optical-transport networks. Although this technology has demonstrated good optical performance, its ability to expand to the required port-count while remaining within reasonable optical loss budgets has yet to be demonstrated. In this paper, we theoretically analyze the expandability of

Lih-Yuan Lin; Evan L. Goldstein; Robert W. Tkach

2000-01-01

34

Optical cross-connect architecture using free-space optical switches based on PI-LOSS topology  

Microsoft Academic Search

An optical cross-connect (OXC) system is an essential ingredient needed to create an optical transport network for B-ISDN. We propose an OXC architecture, incorporating failure restoration based on reserved wavelengths, which consists of a routing block and bypass block. We compare the number of required optical devices in our structure with a conventional structure. We also propose a polarization controlled

S. Kuroyanagi; K. Hironishi; T. Maeda

1995-01-01

35

EVALUATION OF THE ABILITY OF CHLORINE TO INACTIVATE SELECTED ORGANISMS FROM THE BIOFILM OF A DRINKING WATER DISTRIBUTION SYSTEM SIMULATOR FOLLOWING A LONG-TERM WASTEWATER CROSS-CONNECTION  

EPA Science Inventory

The drinking water distribution system simulator (DSS) from the U.S. EPA was operated with a direct cross-connection of 0.3% wastewater to system volume per day for 70 d. During the cross-connection, tap water, wastewater, and system discharge water were monitored to ensure that ...

36

128×128 three-dimensional MEMS optical switch module with simultaneous optical path connection for optical cross-connect systems  

NASA Astrophysics Data System (ADS)

A 128×128 three-dimensional MEMS optical switch module and a switching-control algorithm for high-speed connection and optical power stabilization are described. A prototype switch module enables the simultaneous switching of all optical paths. The insertion loss is less than 4.6dB and is 2.3dB on average. The switching time is less than 38ms and is 8ms on average. We confirmed that the maximum optical power can be obtained and optical power stabilization control is possible. The results confirm that the module is suitable for practical use in optical cross-connect systems.

Mizukami, Masato; Yamaguchi, Joji; Nemoto, Naru; Kawajiri, Yuko; Hirata, Hirooki; Uchiyama, Shingo; Makihara, Mitsuhiro; Sakata, Tomomi; Shimoyama, Nobuhiro; Oda, Kazuhiro

2011-07-01

37

Effect of Correlations of Component Failures and Cross-Connections of EDGs on Seismically Induced Core Damages of a Multi-Unit Site  

NASA Astrophysics Data System (ADS)

Aiming at proposing effective applications of seismic probabilistic safety assessment (PSA) for design and risk management of nuclear facilities, we conducted a preliminary seismic PSA study for a multi-unit site to examine core damage frequency (CDF) and core damage sequences with consideration of the effect of correlations of component failures. In addition, we also examined the effectiveness of an accident management measure, namely, cross-connections of emergency diesel generators (EDGs) between adjacent units in this study. Twin BWR-5 units of the same design were hypothesized to be located at the same site in this study and the CDF as well as the accident sequences of this two-unit site were analyzed by using SECOM2, a system reliability analysis code for seismic PSA. The results showed that the calculated CDF was dependent on the assumptions on the correlations of component failures. When the rules for assigning correlation coefficients of component responses defined in the NUREG-1150 program were adopted, the CDF of a single unit, the CDF of this two-unit site (the frequency of core damages of at least one unit at this site) and the frequency of simultaneous core damages of both units increased by factors of about 1.3, 1.2 and 2.3, respectively. In addition, it might be possible that the simultaneous core damages of both units are caused by different accident sequence pairs as well as the same sequence pairs. When cross-connections of EDGs between two units were available, the CDF of a single unit, the CDF of this two-unit site as well as the frequency of simultaneous core damages of both units decreased. In addition, the CDF of this two-unit site was smaller than the CDF of a single unit site. These results show that cross-connections of EDGs might be beneficial for a multi-unit site if the rules for assigning correlation coefficients defined in NUREG-1150 program are reasonable.

Muramatsu, Ken; Liu, Qiao; Uchiyama, Tomoaki

38

Cross-Connections of Chemistry  

NASA Astrophysics Data System (ADS)

We are in desperate need of qualified chemistry teachers. Are the teachers who have biology, physics, or some psychology degrees qualified to teach chemistry? Have they taken enough chemistry to be prepared to teach outside their degree field? If remediation is necessary, what courses should be required? Attracting pre-service science teachers to the study of pure chemistry is not an easy task when more attractive course offerings are available. Maybe we should concentrate on cross-training in-service teachers by providing appropriate graduate courses to encourage them and bring them into the family. Many teachers with degrees outside the traditional discipline of chemistry have adequate backgrounds in the applications of chemistry. Requiring hours of undergraduate education before they enter the hallowed halls of the chemistry building as graduate students only serves to discourage a large segment of in-service teachers who wish to broaden their perspective. The National Science Education Standards make a compelling argument for connecting and integrating science courses for practicing teachers (3). We are at the crossroads. At a time when we so desperately need qualified chemistry teachers, shouldn't we be more open in our graduate teaching programs, inviting those with degrees in other disciplines to start on a graduate degree without insisting on undergraduate or survey coursework first? Many potential chemical education graduate students have a background in chemistry--it is just known by another name.

Mason, Diana S.

2002-02-01

39

CROSS-CONNECTIONS COLLEGE OF LAW  

E-print Network

of redacted FBI documents, compiled witness books, cross-referenced names, and researched information about Ku Klux Klan activities in the region. As a result of their hard work, the FBI and the U.S. Attorney

McConnell, Terry

40

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

DOEpatents

This report discusses a propulsion and stabilization system comprising a series of figure 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 figure 8 coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension.

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

1992-01-01

41

A silicon-cast device that aids in securing rope ends by ensuring a figure-eight knot is tied for use in gym and rock climbing  

E-print Network

Between the years of 1953 and 2005, there were 253 fatalities from rappel failure/error. Some of these deaths may have been prevented if a stopper knot was tied at the end of the rope. Current climbing habits do not reinforce ...

Treadway, Shane M

2008-01-01

42

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...

43

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

CANR | Cooperative Extension | REC | UD Home | UD Directory | UD Daily | Find It (A-Z) | BUDDY Home > Academic Programs > Communications Program > Cooperative Extension > Facilities > Information Bulgarian vets visit UD to learn 'Delaware Model' for containing bird flu Panel sees partnerships as key

Sparks, Donald L.

44

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

45

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

46

THREE-DIMENSIONAL TOWER STRUCTURES WITH INTEGRATED CROSS-CONNECTS FOR 3-D CULTURING OF NEURONS  

Microsoft Academic Search

As the complexity of bioengineered systems continues to increase, there is a need for the creation of geometrically- controlled three-dimensional scaffolds for cellular growth and culturing. Since the size scale of micromachined structures meshes well with that of cells, MEMS technology can be utilized for this application. In this work, three-dimensional (3-D) scaffolds have been generated for 3-D cell culturing.

Yoonsu Choi; Seungkeun Choi; Richard Powers; Mark G. Allen; Yoonkey Nam; Bruce C. Wheeler; Ashley Marr; Gregory J. Brewer

47

Spatial light modulators for full cross-connections in optical networks  

NASA Technical Reports Server (NTRS)

A polarization-independent optical switch is disclosed for switching at least one incoming beam from at least one input source to at least one output drain. The switch includes a polarizing beam splitter to split each of the at least one incoming beam into a first input beam and a second input beam, wherein the first input beam and the second input beams are independently polarized; a wave plate optically coupled to the second input beam for converting the polarization of the second input beam to an appropriately polarized second input beam; a beam combiner optically coupled to the first input beam and the modified second input beam, wherein the beam combiner accepts the first input beam and the modified second input beam to produce a combined beam; the combined beam is invariant to the polarization state of the input source's polarization; and a controllable spatial light modulator optically coupled to the combined beam, wherein the combined beam is diffracted by the controllable spatial light modulator to place light at a plurality of output locations.

Juday, Richard D. (Inventor)

2004-01-01

48

Optical Path Cross-Connect System Scale Evaluation Using Path Accommodation Design for Restricted Wavelength Multiplexing  

Microsoft Academic Search

The optical path (OP) technology, which employs both wavelength-division multiplexing and wavelength routing, will be the key to enhanced network integrity and an ubiquitous broadband integrated services digital network (B-ISDN) in the future. To construct the OP network, path accommodation design that can solve simultaneously the problems of path routing and wavelength assignment must be established. Since optical wavelengths are

Naohide Nagatsu; Satoru Okamoto; Ken-ichi Sato

1996-01-01

49

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

50

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

51

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

52

Optical cross-connect system based on the White cell and three-state microelectromechanical system: experimental  

E-print Network

is limited by the systems' electronic parts, which prevent the use of the transmitting media at their full into two main groups: 2D digital MEMSs and 3D analog MEMSs. In 2D digital MEMSs, the switches are inte- lel to the substrate. Depending on the MEMS, the micromirrors can be tilted, rotated, or lifted

Anderson, Betty Lise

53

CROSS CONNECTIONS SChOOl Of INfORmaTION STudIES (iSChOOl)  

E-print Network

to understanding the impact of information, technology, and media literacies on children and adults · Center, storing, and communicating informa- tion, as well as its impact on society and poli- cies governingSchoolofInformationStudies(iSchool)recognizes the pervasiveness of information technologies in all areas of society--from business and communication

McConnell, Terry

54

Performance enhancements of the CMCC"s national mesh network using the intelligent optical cross-connect switches  

NASA Astrophysics Data System (ADS)

In the last five years, the traffic growth rate in China has been extremely fast. By 2005, the number of wired telephone customers is estimated to reach 220 to 260 million, while the number of expected cellular customers will reach 260 to 290 million. To meet these challenges, we will continue evolving with more wavelengths and higher speed. By evolving point-to-point WDM systems to OTN/ASON systems, we can eliminate the throughput bottleneck of network nodes caused by electronics, provide optical-layer bandwidth- management capability, provide scalability (which allows continuous traffic growth and network expansion), and provide reconfigurability (which allows semi-dynamic and dynamic optical networking). We can also simplify and speed up provisioning of high-speed circuits and services and offer fast network protection and restoration on the order of tens or hundreds of milliseconds to guarantee excellent network and service survivability. The CMCC (China Mobile Communication Company) will build its OTN network towards the ASON. The CMCC"s long-haul national network utilizing OXC has clearly becomes an intelligent network. It offers end-to-end point-and-click provisioning, shared mesh restoration with a few tens to a couple of hundred msec restoration times, re-provisioning of connections in the event of double failures and network capacity that is not optimally used. In this paper, first we present the CMCC network situation, The network planning tool will be introduced, Then we compare ring with mesh solution in terms of the cost, network performance, protection and restoration, network re-optimization. At last we derive a desired conclusion.

Gong, Qian; Xu, Rong; Lin, JinTong L.

2004-04-01

55

A Novel Architecture of an Optical Cross-connect Based on Tuneable Fibre Bragg Gratings and Optical Circulators  

E-print Network

. In this paper, a novel switching architecture based on thermally tuneable Fibre Bragg Gratings (FBG) and optical) ­ tuneable micro-mirrors placed in a silicon base, `Bubble' switching ­ Gel/Oil based, Electrolographic - electroholographic matrix with ferro-electric crystals, and Fibre Bragg Grating (FBG) Based [1]. Crosstalk

Haddadi, Hamed

56

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...

57

Optical path strategies in WDM all-optical networks: minimization of wavelength converters in optical cross connects  

Microsoft Academic Search

There is a significant debate in progress about the need for translating the wavelength of a signal within an optical network and on the comparison of the performance of the wavelength path (WP) and virtual wavelength path (VWP) approaches. This paper investigates these issues in more depth. An analysis of the algorithms allowing VWP and WP schemes is reported. Their

Marco Listanti; Massimo Berdusco; Roberto Sabella

1997-01-01

58

Comparison of Wavelength-Interchanging and Wavelength-Selective Cross-Connects in Multiwavelength All-Optical Networks  

Microsoft Academic Search

We quantify the benefits of wavelength interchanging in terms of the required capacity and the blocking probability. Most of the previous work on this subject assumed single-fiber links; we study networks with multiple fibers, extend Barry's (see Proceedings of IEEE INFOCOM '95, vol.2, p.402, 1995) probability analysis to the multifiber case, and compare those results with fiber gain calculations in

Gibong Jeong; Ender Ayanoglu

1996-01-01

59

Wavelength Conversion in WDM Optical Networks: Strategies and Algorithms for Limiting the Number of Converters in the Optical Cross-Connects  

Microsoft Academic Search

This paper considers the problem of wavelength conversion in optical networks using wavelength division multiplexing technique. In the previous literature, two main wavelength routing and assignment strategies have been introduced: wavelength path (WP) and virtual wavelength path (VWP), depending on whether the signal stays on the same wavelength or is converted to another during its travel throughout the network. While

Marco Listanti; Roberto Sabella

2000-01-01

60

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

61

Transformation of contrails into cirrus during SUCCESS  

Microsoft Academic Search

Three contrail systems were analyzed with geostationary satellite data to document the conversion of the contrails to cirrus clouds. Two unique contrails, a pair of figure eights and a NASA DC-8 oval, were tracked for more than 7 hours. A cluster of contrails from commercial aircraft lasted over 17 hours. The figure eights produced a cirrus cloud having a maximum

Patrick Minnis; David F. Young; Donald P. Garber; Louis Nguyen; William L. Smith; Rabindra Palikonda

1998-01-01

62

Rev. of American Folk Art: Expressions of a New Spirit, by the staff of the Museum of Folk Art, N.Y. City  

E-print Network

. The calligraphy is copied from a Piatt Rogers Spencer handwriting copybook. FIGURE EIGHT: (Below): "Hemfield Railroad," a double-weave Jacquard loom coverlet, wool, about 1856, possibly by Daniel Campbell. Illustrations courtesy of the Museum of American Folk...

Levine, Stuart

1986-01-01

63

Independent gain and bandwidth control of a traveling wave maser  

NASA Technical Reports Server (NTRS)

An X-band traveling wave maser of the folded-comb type is presented, with two figure-eight coils for gain and bandwidth control. One figure-eight coil covers the full lengths of the comb structure for bandwidth adjustment of an external magnetic field. The other coil covers a central half of the comb structure for independent gain adjustment of the external magnetic field. The half of each figure-eight coil at the turn around end of the comb structure is oriented to aid the external magnetic field, and the half of each coil at the input-output end of the comb structure is oriented to buck the external magnetic field. The maser is pumped in the push-push mode with two different frequencies.

Trowbridge, D. L. (inventor)

1977-01-01

64

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...

65

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...

66

Knot Universes in Bianchi Type I Cosmology  

E-print Network

We investigate the trefoil and figure-eight knot universes from Bianchi-type I cosmology. In particular, we construct several concrete models describing the knot universes related to the cyclic universe and examine those cosmological features and properties in detail. Finally some examples of unknotted closed curves solutions (spiky and Mobius strip universes) are presented.

Ratbay Myrzakulov

2012-04-04

67

60 FR 21504 - Government-Owned Inventions; Availability for Licensing  

Federal Register 2010, 2011, 2012, 2013

...354,420: METHOD FOR LASER-ASSISTED ETCHING OF...LOCKED, FIGURE EIGHT LASER WITH EXTRACAVITY FEEDBACK...AND AZIMUTH BY USE OF A COHERENT SIDE LOBE CANCELLER SYSTEM...Patent 5,362,450: LASER CONTROLLED DECOMPOSITION...APPARATUS FOR PRODUCING IMAGES ACOUSTICALLY;...

1995-05-02

68

Hybrid Fractal Zerotree Wavelet Image Taekon Kim, Robert E. Van Dyck, and David J. Miller  

E-print Network

1 Hybrid Fractal Zerotree Wavelet Image Coding Taekon Kim, Robert E. Van Dyck, and David J. Miller the scaling factor aR the encoding bit rate bR a rate slightly less than the encoding rate fR the fractal. of Tables Four tables No. of Figures Eight figures Keywords hybrid fractal coding, zerotree, image

69

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

70

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

71

Effects of wavelength routing and selection algorithms on wavelength conversion gain in WDM optical networks  

Microsoft Academic Search

Wavelength division multiplexing technology is emerging as the transmission and switch- ing mechanism for future optical mesh networks. In these networks, it is desired that a wavelength can be routed without electrical conversions. Two technologies are possible for this purpose: Wavelength Selective Cross-Connects (WSXC), and Wavelength Interchanging Cross-Connects (WIXC) which involve wavelength conversion. It is believed that wavelength converters may

Ezhan Karasan; Ender Ayanoglu

1998-01-01

72

Magnetic Suspension and Propulsion Systems for High-Speed Transportation  

Microsoft Academic Search

High-speed transportation vehicles (trains) carrying superconducting magnets can be levitated by repulsion from diamagnetic currents induced in a conducting track. Various approximate methods are presented for calculating the lift and drag forces for such magnetic suspensions. Fourier analysis of periodic train magnet fields is used to analyze ``image-force'' and ``hybrid null-flux'' systems which involve homogeneous conducting sheet tracks. A lumped

P. L. Richards; M. Tinkham

1972-01-01

73

Dragonfly (Sympetrum flaveolum) flight: Kinematic measurement and modelling  

NASA Astrophysics Data System (ADS)

The kinematics of the flapping hindwing of the dragonfly Sympetrum flaveolum is investigated. Several tracking points along the leading edge and trailing edge of the hindwing are recorded and studied using high-speed videography. By applying more tracking points along the leading edge around the nodus, it is shown that the leading edge is not one rigid piece, but two pieces hinged at the nodus with physical constraint of forty degrees. Such arrangement also eases the difficulties in rotating the wing during pronation by bending the leading edge forward and flattening the wing. From the kinematic experiments, two flapping patterns of the dragonfly wing are revealed as a simple figure-eight and a double figure-eight flapping pattern. Kinematic modelling of the two flapping patterns is then established by transforming the flapping motions into angular rotations about the pivoting wing root in a local body-fixed spherical coordinate system.

Chen, Y. H.; Skote, M.; Zhao, Y.; Huang, W. M.

2013-07-01

74

Tight and loose shapes in flat entangled dense polymers  

E-print Network

We investigate the effects of topological constraints (entanglements) on two dimensional polymer loops in the dense phase, and at the collapse transition (Theta point). Previous studies have shown that in the dilute phase the entangled region becomes tight, and is thus localised on a small portion of the polymer. We find that the entropic force favouring tightness is considerably weaker in dense polymers. While the simple figure-eight structure, created by a single crossing in the polymer loop, localises weakly, the trefoil knot and all other prime knots are loosely spread out over the entire chain. In both the dense and Theta conditions, the uncontracted knot configuration is the most likely shape within a scaling analysis. By contrast, a strongly localised figure-eight is the most likely shape for dilute prime knots. Our findings are compared to recent simulations.

Andreas Hanke; Ralf Metzler; Paul G. Dommersnes; Yacov Kantor; Mehran Kardar

2003-07-24

75

Dynamics of an electron driven by relativistically intense laser radiation  

SciTech Connect

The dynamics of an electron driven by a relativistically intense laser pulse is analyzed on the basis of the equation of motion with the Lorentz force in the cases of linear and circular polarizations. Laser fields with nonplane phase fronts accelerate electrons in the longitudinal direction. An electron initially at rest is found not to move along figure-eight trajectories for the linear polarization, and not to move along circular trajectories for the circular polarization.

Galkin, A. L.; Korobkin, V. V.; Romanovsky, M. Yu.; Shiryaev, O. B. [Coherent and Nonlinear Optics Department, A.M. Prokhorov General Physics Institute of the Russian Academy of Science, Box 119991, 38 Vavilov Street, Moscow (Russian Federation)

2008-02-15

76

Biomechanical comparison of wire osteosynthesis techniques in craniofacial surgery.  

PubMed

The biomechanical stability of 20 different craniofacial wire osteosynthesis methods were tested in a simulated bone model. Utilizing wire fixation across a curved osteotomy site of an acrylic bar fixed at one end, compressive loading at the suspended end was used to test the resistance of the ligatures to stretch failure. Twenty-eight- and 30-gauge ligature patterns tested included single loops, double loops, and figure-eights across both 1- and 2-cm distances. A two-way analysis of variance was then used to determine the various effects of wire diameter, configuration, and loop length. The extensional deformation of ligature fixation was shown to be reduced by increasing the number of wire loops, reducing intraloop distances, or employing a slightly larger gauge diameter. The complex wiring configuration of a figure-eight technique was of no advantage over simple wire loops. In comparative strengths, two double loops were stronger than one double loop, and two single loops were stronger than one single loop or figure-eight. Comparable reductions in fixation strength were seen in all groups; there were larger intrabony distances between the burr holes or with the smaller gauge wire. These biomechanical ligature testing results are useful in those craniofacial skeletal sites where the use of more rigid fixation is either contraindicated or not desired. PMID:8031977

Eppley, B L; Elluru, R; Sadove, A M

1994-02-01

77

Collection of Remarkable Three-Body Motions  

NSDL National Science Digital Library

This collection of EJS models shows the motions of three or more bodies attracted to one another by gravitational forces. The following applets are included in the collection: Restricted three-body problem - a satellite in the binary planet system Examples of the restricted three-body problem (in two frames of reference) Figure-eight periodic planar three-body motion Figure-eight three-body motion in two frames of reference Variations of figure-eight planar three-body motion Three-body motions in the equilateral configuration Regular planar motions of four bodies of equal masses These Java applets allow us to observe fascinating trajectories of three-body motions that delight the eye and challenge our intuition. However, among the great variety of extremely complex motions there exist a finite subset of very simple regular motions. Some of these regular motions are also illustrated in this collection. EJS applets on this site were created with EJS version 2.0 and are not compatible with the latest version of EJS.

Butikov, Eugene

2010-01-28

78

Magnetization process of a single magnetic ring detected by nonlocal spin valve measurement  

E-print Network

cross connecting the ring to the pad was fabricated using lithographer followed by resistance heating of the magnetic ring easily.12 However, the interlayer coupling between magnetic layers may affect the domain

Otani, Yoshichika

79

75 FR 78794 - Self-Regulatory Organizations; EDGX Exchange, Inc.; Notice of Filing and Immediate Effectiveness...  

Federal Register 2010, 2011, 2012, 2013

...cross-connection or an external telecommunication circuit). By contrast, a ``logical'' port (also commonly referred to as a TCP/IP port) represents a port established by the Exchange within the Exchange's system for trading and billing purposes....

2010-12-16

80

75 FR 78791 - Self-Regulatory Organizations; EDGA Exchange, Inc.; Notice of Filing and Immediate Effectiveness...  

Federal Register 2010, 2011, 2012, 2013

...cross-connection or an external telecommunication circuit). By contrast, a ``logical'' port (also commonly referred to as a TCP/IP port) represents a port established by the Exchange within the Exchange's system for trading and billing purposes....

2010-12-16

81

Project W-320 high vacuum 241-AY-102 annulus ventilation system operability test report  

SciTech Connect

This report documents the test results of OTP-320-001, Tank 241-AY-102 Annulus Ventilation System Testing. Included in the appendices are: (1) Supporting documentation prepared to demonstrate the structural integrity of the tank at high annulus vacuum (<20 INWG), and (2) a report that identifies potential cross connections between the primary and annulus ventilation systems. These cross connections were verified to be eliminated prior to the start of testing.

Bailey, J.W.

1998-03-12

82

Survivable WDM Mesh Networks, Part 1 - Protection  

Microsoft Academic Search

This investigation considers optical networks which employ wavelength cross-connects that enable the establishment of wavelength-division-multiplexed (WDM) channels, between node-pairs. In such and other networks, the failure of a network element (e.g., fiber link, cross-connect, etc.) may cause the failure of several optical channels, thereby leading to large data losses. This study examines different approaches to protect mesh based WDM optical

S. Ramamurthy; Biswanath Mukherjee

1999-01-01

83

A large-scale photonic node architecture that utilizes interconnected OXC subsystems.  

PubMed

We propose a novel photonic node architecture that is composed of interconnected small-scale optical cross-connect subsystems. We also developed an efficient dynamic network control algorithm that complies with a restriction on the number of intra-node fibers used for subsystem interconnection. Numerical evaluations verify that the proposed architecture offers almost the same performance as the equivalent single large-scale cross-connect switch, while enabling substantial hardware scale reductions. PMID:23388942

Iwai, Yuto; Hasegawa, Hiroshi; Sato, Ken-ichi

2013-01-14

84

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

85

The Stealth Biplane: a Proposal in Response to a Low Reynolds Number Station Keeping Mission  

NASA Technical Reports Server (NTRS)

The Stealth Biplane is conceived and constructed to serve as a remotely piloted vehicle designed to navigate a low-level figure-eight course at a target Reynolds number of 100,000. This flight vehicle will combine the latest in lightweight radio controlled hardware in conjunction with current low Reynolds number aerodynamic research to demonstrate feasible operation in a variety of applications. These potential low Reynolds number applications include high altitude atmospheric sampling, search and rescue, and even law enforcement. Design specs and fabrication technique are discussed.

Walsh, Timothy E.; Flynn, Kevin T.; Donovan, Steven; Paul, Chris; Pangilinan, Harold; Padgett, John; Twomey, Daniel

1990-01-01

86

Flexible polyvinyl chloride neutron guides for transporting ultracold and very cold neutrons  

SciTech Connect

The transmission of ultracold neutrons (UCNs) through flexible polyvinyl chloride (PVC) tubes with lengths of up to 3 m and an internal diameter of 6-8 mm has been studied. High UCN transmission is found even for arbitrarily bent tubes (single bend, double bend, triple bend, figure eight, etc.). The transmission can be improved significantly by coating the inner surface of the tube with a thin layer of liquid fluorine polymer. The prospects of these neutron guides in fundamental and applied research are discussed.

Arzumanov, S. S., E-mail: sarzumanov@yandex.ru; Bondarenko, L. N. [Russian Research Center Kurchatov Institute (Russian Federation); Geltenbort, P. [Institut Laue-Langevin (France); Morozov, V. I. [Russian Research Center Kurchatov Institute (Russian Federation); Nesvizhevsky, V. V. [Institut Laue-Langevin (France); Panin, Yu. N.; Strepetov, A. N.; Chuvilin, D. Yu. [Russian Research Center Kurchatov Institute (Russian Federation)

2011-12-15

87

Orbit Program  

NSDL National Science Digital Library

The Orbit program displays the dynamics of multiple massive objects interacting gravitationally. The default scenario shows the figure-eight orbit of three particles first discovered by Montgomery. Additional particles and their initial positions and velocities can be specified using the Display | Switch GUI menu item. Orbit is an Open Source Physics program written for the teaching of classical orbits. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the mech_orbit.jar file will run the program if Java is installed. Other classical mechanics programs are also available. They can be found by searching ComPADRE for Open Source Physics, OSP, or mechanics.

Christian, Wolfgang

2008-05-20

88

SPECIAL ISSUE DEVOTED TO THE 25th ANNIVERSARY OF THE A.M. PROKHOROV GENERAL PHYSICS INSTITUTE: Relativistic motion and radiation of an electron in the field of an intense laser pulse  

NASA Astrophysics Data System (ADS)

The motion of an electron in the fields of relativistic-intensity linearly and circularly polarised laser radiation is analysed. The analysis is based on the numerical solution of the Newton equation with the Lorentz force. The electromagnetic radiation of an electron interacting with a laser pulse is studied. It is shown that this radiation is emitted in the form of extremely short attosecond pulses. It is found that an initially immobile electron does not move along figure-eight trajectories in the field of a linearly polarised laser pulse.

Galkin, A. L.; Korobkin, V. V.; Romanovskii, M. Yu; Shiryaev, O. B.

2007-10-01

89

Localized stimulation of the human brain and spinal cord by a pair of opposing pulsed magnetic fields  

NASA Astrophysics Data System (ADS)

A method of localized stimulation of the human brain and spinal cord is proposed. The basic idea is to concentrate induced eddy currents locally in the vicinity of a target by a pair of opposing pulsed magnetic fields. A pair of coils are positioned outside the head in the opposite directions around a target. The eddy currents induced at the target are expected to flow together, which results in an increased current flow at the target. A figure-eight coil is designed, and the magnetic brain stimulation is carried out using ourselves as volunteers. The results show that the selective stimulation of the brain is realized with a 5-mm resolution. The functional mapping of the human motor cortex related to the hand, arm, and foot areas is obtained. It is also obtained that an optimum direction of stimulating currents for neural excitation exists in each functional area in the cortex. Magnetic stimulation of the spinal cord is carried out by the same method as used in the brain stimulation. Rabbits are used in the experiments. A figure-eight coil is positioned on the surface of the spine. Shifting the stimulating points on the spine, electromyographic (EMG) signals are recorded from limb muscles. The EMG signals are clearly responding to the stimulation at a segment which innervates limb muscles, whereas no EMG signals are obtained by stimulation of segments higher than the critical segment. It is also obtained that the amplitude of the EMG signals varies with the direction of stimulating currents.

Ueno, S.; Matsuda, T.; Hiwaki, O.

1990-05-01

90

Three years of rainfall over the Indian Ocean  

NASA Technical Reports Server (NTRS)

Monthly rain falling on the Indian Ocean is mapped for the period 1979 through 1981 by means of observations of the Nimbus-7 Scanning Multichannel Microwave Radiometer. Both stationary and mobile parts were found in the pattern of rain. The stationary part consisted of three zonal and two meridional bands. Only one, the band along and south of the equator, maintained a strong presence through all seasons. A north equatorial counterpart to this south equatorial band also was persistent, but weak. The mobile part of the pattern took the form of a wave. The locus of this wave was an eastward-tilted figure eight, which straddled the equator. The wave moved clockwise along the north loop of the figure eight, counterclockwise along the south loop. The crest of the wave crossed the equator from south to north in May or June and crossed the equator from north to south between August and October. Along its path the equatorial bands were alternately amplified and damped, and the transient bands were activated and suppressed. The effect of the bands and wave was to produce a strong 'monsoon' (annual cycle, summer peak) signature in rain falling over both the northeastern and southwestern reaches of the Indian Ocean.

Martin, David W.; Hinton, Barry B.; Auvine, Brian A.

1993-01-01

91

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.

92

Backflow prevention and responsibilities of HVAC professionals  

SciTech Connect

This article highlights the seriousness of backflow of harmful substances into potable water systems from cross-connections with other systems. Topics include backflow hazard examples, taking action, piping system surveys. The examples cited included schools, police station, hospitals, and a college. The contaminants included heat transfer fluids and corrosion inhibitors such as zinc chromate and ethylene glycol.

Towle, N. [Towle-Whitney Associates, Inc., Manchester, NH (United States)

1996-09-01

93

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

94

Analysis of Supportable Rates in Symmetric Blocking Wavelength Routers  

E-print Network

Analysis of Supportable Rates in Symmetric Blocking Wavelength Routers Can Emre Koksal EPFL School-- Constructing an n Ã? n non-blocking wavelength router using n Ã? n optical cross-connects may be impractical due requirements can be handled without a non-blocking router. In this paper, we study blocking wavelength routers

Koksal, Can Emre

95

78 FR 76341 - Self-Regulatory Organizations; Financial Industry Regulatory Authority, Inc.; Notice of Filing of...  

Federal Register 2010, 2011, 2012, 2013

...connect to FLOW via the FLOW Smart Order Router, or through the FLOW Gateway. Non-FLOW...production environment to most outbound routers via intranets, cross connects and other...subscribers may use either the FLOW Smart Order Router or the FLOW Gateway, and...

2013-12-17

96

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

97

Analysis of the potential benefits of OXC-based intelligent optical networks  

Microsoft Academic Search

This paper analyses three quantifiable benefits of Optical Cross Connect (OXC) architectures and how these are affected by network topology and traffic characteristics. The cost-saving benefits of shared protection, the revenue increasing potential of dynamic provisioning, and the efficiency gains of network reconfiguration are analysed. All three of these benefits are available when an OXC-enabled intelligent optical core network is

Neil Gear; Andreas Antonopoulos; John O'Reilly

2002-01-01

98

IP over WDM network traffic engineering approaches  

Microsoft Academic Search

The wide spread deployment of DWDM and reconfigurable optical cross-connect equipment gives rise to a new generation of IP over WDM networks. These network combine gigabit and terabit IP routers with WDM switching and transmission systems to create a more flexible and dynamic network. As these networks grow, there is an urgent need to develop and implement new traffic engineering

J. Y. Wei

2002-01-01

99

Traffic engineering for virtual private networks and random traffic demands in WDM optical core networks  

Microsoft Academic Search

Two main classes of traffic demands may be considered in data networks: virtual private networks (VPN) and random traffic requests. In this paper, we investigate traffic engineering for such traffic classes in the context of hybrid WDM optical networks. A hybrid optical network is made of a set of multi-granularity switches, each electrical cross-connect (EXC) of the network being coupled

Elias A. DOUMITH; Maurice GAGNAIRE; Olivier AUDOUIN; Nicolas PUECH

2005-01-01

100

A new strategy for employing wavelength conversion in WDM optical networks  

Microsoft Academic Search

Here we propose a new strategy for wavelength conversion in WDM networks, and a new algorithm that allows the strategy to be adopted, which aim the same performance of virtual wavelength path (VWP) to be reached, but with a strongly reduced number of wavelength converters. This means a significant saving in cost and complexity of the optical cross connects (OXC)

Marco Listanti; M. Berdusco; R. Sabella

1997-01-01

101

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.

102

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...

103

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

Microsoft Academic Search

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

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

2008-01-01

104

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

105

Coastal Management case study  

NSDL National Science Digital Library

To prepare for the case study, lecture material on coastal landforms and processes is presented. Particular attention is paid to barrier islands, such as the Outer Banks. During the lecture, typical coastal engineering structures, such as groins, breakwaters, and jetties, are introduced. The case study is introduced with a brief overview of North Carolina's coastal management laws, Figure Eight Island's geography, and the current controversy over whether to build a terminal groin. Students are then broken down into small groups and presented with two opposing editorials. The groups are instructed to try to come to consensus as to whether the terminal groin should be allowed or disallowed or to suggest a third alternative. After approximately 25 minutes, each group informally reports out to the rest of the class.

Jefferson, Anne

106

A New Solution to the Three Body Problem  

NSDL National Science Digital Library

The subject of this month's feature column from the American Mathematical Society Online is the solution to the "Three Body Problem" of Newtonian mechanics. The problem deals with three orbiting bodies of equal mass and the paths that they will take relative to one another. Solutions have been proposed by many, including Euler, Lagrange, and G.W. Hill. The article notes that solutions are sometimes called "choreographies." The well-written explanatory text discusses the figure-eight orbit, the triangle construction, other choreographies with >3 bodies, and the search for exotic orbits. It includes user-driven Java applets as demonstrations. This site should be interesting to mathematicians and non-mathematicians alike.

Casselman, Bill.

2001-01-01

107

Lorentz force on an electron in a strong plane-wave laser field and the low-frequency limit for ionization  

SciTech Connect

A motion of a classical free charge in an electromagnetic plane wave can be found exactly in a fully relativistic case. I have found an approximate non-parametric form of the suitable equations of motion. In a linearly polarized wave, in the simplest frame of reference, the charge moves along the well-known figure-eight path. I have numerically calculated the Lorentz force acting on the charge as a function of time. By virtue of this, for the low-frequency ionization (or detachment) rate, I discuss a manifestation of nondipole and relativistic effects. When intensity of the plane wave increases, these effects can first appear in angular distributions, then in spectra of outgoing electrons, but have quite little effect on total ionization rates. I try to give an explanation of the latter fact.

Bauer, Jaroslaw H. [Katedra Fizyki Teoretycznej Uniwersytetu Lodzkiego, Ul. Pomorska 149/153, PL-90-236 Lodz (Poland)

2010-01-15

108

Design and fabrication of the multipinch experimental device  

SciTech Connect

The multipinch experimental device was constructed to study the stability and plasma confinement properties of a reversed-field pinch (RFP) with a magnetic well. The magnetic well is created by shaping an RFP configuration into two equal-current lobes in which the poloidal field cancels at the X point of a figure-eight-shaped magnetic separatrix. The design and construction of a 0.525-m major radium modular machine to study this unique plasma configuration is described. A novel construction technique for the noncircular cross-section plasma chamber, incorporating a thin metal skin, phenolic honeycomb, and graphite/epoxy composite bonded sandwich structure, is discussed. Details of the fabrication of the vacuum liner, conducting shell, the toroidal and poloidal coil systems, and the iron core are given.

Curwen, B.; Graumann, D.W.; La Haye, R.J.

1987-09-01

109

Magnetic resonance imaging of time-varying magnetic fields from therapeutic devices.  

PubMed

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 and radiofrequency hyperthermia probes. A method to image such time-varying magnetic fields is introduced in this study. 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 was 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

2013-06-01

110

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

111

Resource Management in STARGATE-Based Ethernet Passive Optical Networks (SG-EPONs)  

Microsoft Academic Search

At present there is a strong worldwide push toward bringing fiber closer to individual homes and businesses. Another evolutionary step is the cost-effective all-optical integration of fiber-based access and metro networks. STARGATE (IEEE Commun. Mag., vol. 45, no. 5, pp. 50-56, May 2007) is an all-optical access-metro architecture that does not rely on costly active devices, e.g., optical cross connects

Lehan Meng; Chadi M. Assi; Martin Maier; Ahmad R. Dhaini

2009-01-01

112

A reconfigurable ethernet\\/SONET circuit-based metro network architecture  

Microsoft Academic Search

We propose a service concept in which high-speed Ethernet interfaces from end hosts are dynamically cross-connected to equivalent-rate Ethernet-over-SONET (EoS) optical circuits for transport across metro-area networks and\\/or wide-area networks. We call our service concept reconfigurable Ethernet\\/SONET circuits to end users (RESCUE). We describe how RESCUE can be used for two applications: dial-up service to Internet service provider routers and

Malathi Veeraraghavan; Xuan Zheng

2004-01-01

113

A wideband all-optical WDM network  

Microsoft Academic Search

We describe some of the results of the Advanced Research Projects Agency (ARPA) sponsored Consortium on Wideband All-Optical Networks in developing architectures, technology components, and applications for the realization of scaleable, wideband, and transparent optical wavelength-division multiplexing (WDM) networks. Our architecture addresses all-optical transport over the wide, metropolitan, and local areas. It utilizes wavelength partitioning, routing, and active multiwavelength cross-connect

I. P. Kaminow; C. R. Doerr; C. Dragone; T. Koch; U. Koren; A. A. M. Saleh; A. J. Kirby; C. M. Ozveren; B. Schofield; R. E. Thomas; R. A. Barry; D. M. Castagnozzi; V. W. S. Chan; D. Marquis; S. A. Parikh; M. L. Stevens; E. A. Swanson; S. G. Finn; R. G. Gallager

1996-01-01

114

Large N x N waveguide grating routers  

Microsoft Academic Search

We show how the grating diffraction properties of a N×N waveguide grating router (WGR) can limit the size of N when the device operates with a unique set of N wavelengths as a strict-sense nonblocking N×N cross connect. We motivate why for large N, the N optical channels should be chosen equally spaced in wavelength and not in frequency. Two

P. Bernasconi; C. Doerr; C. Dragone; M. Cappuzzo; E. Laskowski; A. Paunescu

2000-01-01

115

Dissolved Organic Matter Dynamics in two Suburban Catchments in NE England  

NASA Astrophysics Data System (ADS)

Recent advances in fluorescence spectrophotometry enable rapid and optically precise analysis of river dissolved organic matter (DOM). In this study we investigate the potential of detecting river pollution associated with urban expansion (cross connected sewerage; overloading of combined sewer overflows (CSOs), land use change) using fluorescence and absorbance spectrophotometry, paired with conventional geochemistry, microbiological analyses and 14C/13C isotope fingerprinting of dissolved organic matter, in two small, rural-urban fringe catchments in NE England over the period 2002-present. In the United Kingdom, `suburbia' (post 1945AD) is distinguished by separate sewerage systems and associated issues of cross connections. Results indicate: (1) suburban catchments have a seasonal trend in DOM fluorescence, with a maximum of tryptophan-like fluorescence in summer low flow, indicative of an increased proportion of cross connected sewer inputs, with a statistically significant inverse relationship with discharge. Older `urban' catchments with CSOs exhibit an opposite seasonality, with combined sewerage overflows occurring in winter at high flow due to CSO discharge. (2) Sampling cross connected storm drains for both Escherichia coli. and fluorescence demonstrates a statistically significant relationship. This finding matches laboratory microbial cultures, which have demonstrated that a wide range of environmentally relevant microbes exhibit tryptophan-like fluorescence, and suggests that when coliforms dominate a river or wastewater microbial community then fluorescence intensity could potentially be employed to monitor faecal coliforms in urban waters. (3) 14C/13C fingerprinting of DOM in three contrasting sub-catchments separates urban and industrial DOM sources through positive 13C and `old' 14C.

Baker, A.; Simpson, E.; Bryant, C.

2005-12-01

116

The A-VPN server: a solution for ATM virtual private networks  

Microsoft Academic Search

The paper presents an architectural element to be included in an ATM cross-connect in order to provide essential features for the deployment of an ATM based virtual private network service (A-VPN service). The A-VPN server aims at a solution of the egress policing problem (bandwidth enforcement function) and incorporates a set of functionalities devoted to the support of an effective

P. Coppo; M. D'Ambrosio; V. Vercellone

1994-01-01

117

Wavelength conversion in optical transport networks  

Microsoft Academic Search

The introduction of optical technology in the path layer of a transport network is analyzed; in particular, the impact of all-optical wavelength conversion is examined. Two basic optical cross-connect schemes based on space switching and on wave-length switching, respectively, and two types of wavelength converters are considered. The wavelength converters are, respectively, based on four-wave miring (FWM) in semiconductor optical

R. Sabella; E. Iannone

1996-01-01

118

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

119

Cross-linker system between neurofilaments, microtubules and membranous organelles in frog axons revealed by the quick-freeze, deep-etching method  

PubMed Central

The elaborate cross-connections among membranous organelles (MO), microtubules (MT), and neurofilaments (NF) were demonstrated in unifixed axons by the quick-freeze, deep-etch, and rotary-shadowing method. They were categorized into three groups: NF-associated cross-linker, MT-associated cross-bridges, and long cross-links in the subaxolemmal space. Other methods were also employed to make sure that the observed cross-connections in the unfixed axons were not a result of artifactual condensation or precipitation of soluble components or salt during deep-etching. Axolemma were permeablized either chemically (0.1% saponin) or physically (gentle homogenization), to allow egress of their soluble components from the axon; or else the axons were washed with distilled water after fixation. After physical rupture of the axolemma or saponin treatment, most of the MO remained intact. MT were stabilized by adding taxol in the incubation medium. Axons prepared by these methods contained many longitudinally oriented NF connected to each other by numerous fine cross-linkers (4-6 nm in diameter, 20-50 nm in length). Two specialized regions were apparent within the axons: one composed of fascicles of MT linked with each other by fine cross-bridges; the other was in the subaxolemmal space and consisted of actinlike filaments and a network of long cross-links (50-150 nm) which connected axolemma and actinlike filaments with NF and MT. F-actin was localized to the subaxolemmal space by the nitrobenzooxadiazol phallacidin method. MO were located mainly in these two specialized regions and were intimately associated with MT via fine short (10-20 nm in length) cross-bridges. Cross-links from NF to MO and MT were also common. All these cross-connections were observed after chemical extraction or physical rupture of the axon; however, these procedures removed granular materials which were attached to the filaments in the fresh unextracted axons. The cross-connections were also found in the axons washed with distilled water after fixation. I conclude that the cross- connections are real structures while the granular material is composed of soluble material, probably protein in nature. PMID:6181077

Hirokawa, N

1982-01-01

120

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

121

Advances in polymer-based dynamic photonic components, modules, and subsystems  

NASA Astrophysics Data System (ADS)

We describe recent advances in optical communication components, modules, and subsystems based on planar polymer technologies. The dynamic organic photonic integrated circuits exhibit ultra low power consumption through thermo-optic actuation for switching, routing, and tuning. The components (switches, optical cross-connects (OXC), variable optical attenuators (VOA), tunable couplers, etc.) have state-of-the-art performance, meet reliability requirements in the telecommunication industry including Telcordia GR-1209 and GR-1221 qualification, and are broadly deployed in the field. The modules and subsystems include variable multiplexers (VMUX) and reconfigurable optical add/drop multiplexers (ROADM), and they meet the requirements of Telcordia GR-1312 and GR-63 protocols.

Eldada, Louay

2006-09-01

122

Deterioration in Heat Transfer due to Axial Conduction of Heat in Open Cell Metal Foam  

NASA Astrophysics Data System (ADS)

Cross-connection in the foam struts helps achieving augmentation in heat transfer. It is the same feature which adds the risk of promoting axial conduction. Fluid flow through a slice of open-cell foam, attached to a plate, has been considered for analysing the effect of axial conduction through the porous medium. A repetitive simple cubic structure model for the porous matrix has been assumed for simplicity. While, thermal gradient in the solid plate is always associated with axial flow of heat, existence of the same through the foam filaments becomes conditional. Axial heat flow through the foam-fibres has been found causing substantial deterioration in heat transfer.

Ghosh, Indranil

2010-05-01

123

[The quadriga syndrome: a rarely recognized alteration in hand surgery].  

PubMed

The tendons of flexor digitorum profundus are most often interconnected and making them less able to move independently than the superficial tendons. The reason for this is the cross connective tissue-ligamentous connection between the tendons of the profundus. The recognition of this so called quadriga phenomenon is important in the clinical practice, when the presence of this syndrome hinders the strength and the movement of the tendons after operative reconstruction. In his work the author describes the anatomical foundation, the biomechanical correlations and the clinical importance of the quadriga syndrome in the mirror of literature data. PMID:24819186

Bíró, Vilmos

2014-05-18

124

Lamar repowering project's creative modeling of old and new wins Marmaduke award  

SciTech Connect

Lamar Light and Power is a municipal utility that has been generating the south eastern Colorado city's electricity since 1920. Rising natural gas and oil costs pushed LL & P to retire its steam plant five years ago and begin hunting for more economic power sources. The answer: repower the existing plant with a state-of-the-art coal-fired circulating fluidized-bed combustor and cross-connect old and new steam turbines. The 120 million dollar project will stabilize the region's electricity rates for many years to come. 10 figs. 1 tab.

Peltier, R.

2008-08-15

125

Propagation of all-optical crosstalk attack in transparent optical networks  

NASA Astrophysics Data System (ADS)

Transparent optical network (TON) is now rapidly booming to be popular, and a threat of an all-optical crosstalk attack with high power will emerge. In this paper, the penalty of crosstalk attack propagation, including intrachannel crosstalk inside the optical cross-connects, as well as direct and indirect interchannel crosstalk within fibers, is evaluated. Our work has proved that these crosstalk attacks do propagate in the TON but with limited propagation stages, which will be useful for the planning, management, and design of TON.

Peng, Yunfeng; Sun, Zeyu; Du, Shu; Long, Keping

2011-08-01

126

Optimal propulsive flapping in Stokes flows.  

PubMed

Swimming fish and flying insects use the flapping of fins and wings to generate thrust. In contrast, microscopic organisms typically deform their appendages in a wavelike fashion. Since a flapping motion with two degrees of freedom is able, in theory, to produce net forces from a time-periodic actuation at all Reynolds numbers, we compute in this paper the optimal flapping kinematics of a rigid spheroid in a Stokes flow. The hydrodynamics for the force generation and energetics of the flapping motion is solved exactly. We then compute analytically the gradient of a flapping efficiency in the space of all flapping gaits and employ it to derive numerically the optimal flapping kinematics as a function of the shape of the flapper and the amplitude of the motion. The kinematics of optimal flapping are observed to depend weakly on the flapper shape and are very similar to the figure-eight motion observed in the motion of insect wings. Our results suggest that flapping could be a exploited experimentally as a propulsion mechanism valid across the whole range of Reynolds numbers. PMID:24343130

Was, Loïc; Lauga, Eric

2014-03-01

127

The Lie-Poisson structure of the reduced n-body problem  

NASA Astrophysics Data System (ADS)

The classical n-body problem in d-dimensional space is invariant under the Galilean symmetry group. We reduce by this symmetry group using the method of polynomial invariants. One novelty of our approach is that we do not fix the centre of mass but rather use a momentum shifting trick to change the kinetic part of the Hamiltonian to arrive at a new, dynamically equivalent Hamiltonian which is easier to reduce. As a result we obtain a reduced system with a Lie-Poisson structure which is isomorphic to \\mathfrak{sp}(2n-2) , independently of d. The reduction preserves the natural form of the Hamiltonian as a sum of kinetic energy that depends on velocities only and a potential that depends on positions only. This splitting allows us to construct a Poisson integrator for the reduced n-body problem which is efficient away from collisions for n = 3. In particular, we could integrate the figure eight orbit in 18 time steps.

Dullin, Holger R.

2013-06-01

128

A kinematic description of the trajectories of Listeria monocytogenes propelled by actin comet tails  

PubMed Central

The bacterial pathogen Listeria monocytogenes propels itself in the cytoplasm of the infected cells by forming a filamentous comet tail assembled by the polymerization of the cytoskeletal protein actin. Although a great deal is known about the molecular processes that lead to actin-based movement, most macroscale aspects of motion, including the nature of the trajectories traced out by the motile bacteria, are not well understood. Here, we present 2D trajectories of Listeria moving between a glass-slide and coverslip in a Xenopus frog egg extract motility assay. We observe that the bacteria move in a number of fascinating geometrical trajectories, including winding S curves, translating figure eights, small- and large-amplitude sine curves, serpentine shapes, circles, and a variety of spirals. We then develop a dynamic model that provides a unified description of these seemingly unrelated trajectories. A key ingredient of the model is a torque (not included in any microscopic models of which we are aware) that arises from the rotation of the propulsive force about the body axis of the bacterium. We show that a large variety of trajectories with a rich mathematical structure are obtained by varying the rate at which the propulsive force moves about the long axis. The trajectories of bacteria executing both steady and saltatory motion are found to be in excellent agreement with the predictions of our dynamic model. When the constraints that lead to planar motion are removed, our model predicts motion along regular helical trajectories, observed in recent experiments. PMID:17485664

Shenoy, V. B.; Tambe, D. T.; Prasad, A.; Theriot, J. A.

2007-01-01

129

Image Treatment of Hybrid Drops in Low Reynolds Number Flow  

NASA Astrophysics Data System (ADS)

Hybrid drops, also known as compound drops, consisting of two dissimilar configurations are encountered in processes such as melting of ice particles in the atmosphere, liquid membrane technology, evaporation of drops in a superheated liquid and in other various industrial operations. The flow fields around such hybrid drops form a basis for a better understanding of these industrial applications. Here we provide exact analytic solutions for a class of 3D/2D hybrid drops immersed in an infinite viscous domain in the limit of low Reynolds number. For mathematical convenience, the geometry of the multiphase droplet is composed of two overlapping spheres (infinitely long cylinders for 2D case) Sa and Sb of radii a and b, respectively, intersecting at a vertex angle ?2. The composite inclusion has the shape resembling a figure-eight lens type of object with a vapor Sa partly protruded into a fluid sphere Sb with a viscosity different from that of the host fluid. The mathematical problem with this twin-sphere assembly in the Stokes flow environment is formulated in terms of Stokes stream function with mixed boundary conditions and solved using the classical method of images. Singularity solutions are obtained for the hybrid droplet embedded in several unbounded flow fields and the force acting on the drop is computed in each case. Streamline topologies show interesting flow patterns and surprising, but interesting flow features are noticed in the case of two-dimensional flows.

Palaniappan, D.

2008-11-01

130

Disturbance of visual search by stimulating to posterior parietal cortex in the brain using transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

In this study, we applied a transcranial magnetic stimulation (TMS) to investigate the temporal aspect for the functional processing of visual attention. Although it has been known that right posterior parietal cortex (PPC) in the brain has a role in certain visual search tasks, there is little knowledge about the temporal aspect of this area. Three visual search tasks that have different difficulties of task execution individually were carried out. These three visual search tasks are the "easy feature task," the "hard feature task," and the "conjunction task." To investigate the temporal aspect of the PPC involved in the visual search, we applied various stimulus onset asynchronies (SOAs) and measured the reaction time of the visual search. The magnetic stimulation was applied on the right PPC or the left PPC by the figure-eight coil. The results show that the reaction times of the hard feature task are longer than those of the easy feature task. When SOA=150 ms, compared with no-TMS condition, there was a significant increase in target-present reaction time when TMS pulses were applied. We considered that the right PPC was involved in the visual search at about SOA=150 ms after visual stimulus presentation. The magnetic stimulation to the right PPC disturbed the processing of the visual search. However, the magnetic stimulation to the left PPC gives no effect on the processing of the visual search.

Iramina, Keiji; Ge, Sheng; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo

2009-04-01

131

Comparison of current distributions in electroconvulsive therapy and transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

We compared current density distributions in electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS) by numerical calculations. The model consisted of an air region and three types of tissues with different conductivities representing the brain, the skull, and the scalp. In the ECT model, electric currents were applied through electrodes with a voltage of 100 V. In the TMS model, a figure-eight coil (6 cm diameter per coil) was placed on the vertex of the head model. An alternating current with a peak intensity of 3.0 kA and a frequency of 4.2 kHz was applied to the coil. The maximum current densities inside the brain in ECT (bilateral electrode position) and TMS were 234 and 322 A/m2, respectively. The results indicate that magnetic stimulators can generate comparable current densities to ECT. While the skull significantly affected current distributions in ECT, TMS efficiently induced eddy currents in the brain. In addition, TMS is more beneficial than ECT because the localized current distribution reduces the risk of adverse side effects.

Sekino, Masaki; Ueno, Shoogo

2002-05-01

132

Auditory deficits and motor dysfunction following iminodipropionitrile administration in the rat.  

PubMed

The behavioral effects of 3,3'-iminodipropionitrile (IDPN) were studied using reflex modification of the acoustic startle response and figure-eight maze activity. A number of experiments were conducted with separate groups of adult male Long-Evans hooded rats exposed to saline or 50-500 mg/kg IDPN for 3 consecutive days. Auditory thresholds (reflex modification), motor activity, and grip strength were measured 1 day, and 1, 3, and 9 weeks postdosing. Reflex inhibition was monitored daily, prior to, during, and for 7 days following exposure. Auditory thresholds for 5- and 40-kHz tones were elevated approximately 25 dB and 50 dB, respectively. The onset of this auditory dysfunction in the 200-mg/kg/day group, as demonstrated by a loss of reflex inhibition, was 2 days for the 40-kHz tone and 4 days for the 5-kHz tone. Motor activity was increased up to 400% in the 200-mg/kg group, whereas there was no alteration in hindlimb grip strength. These data demonstrate dosage- and time-dependent alterations in auditory and motor function following IDPN exposure. PMID:1779945

Crofton, K M; Knight, T

1991-01-01

133

The discrepancy between human peripheral nerve chronaxie times as measured using magnetic and electric field stimuli: the relevance to MRI gradient coil safety  

NASA Astrophysics Data System (ADS)

Peripheral nerve stimulation (PNS) resulting from electric fields induced from the rapidly changing magnetic fields of gradient coils is a concern in MRI. Nerves exposed to either electric fields or changing magnetic fields would be expected to display consistent threshold characteristics, motivating the direct application of electric field exposure criteria from the literature to guide the development of gradient magnetic field exposure criteria for MRI. The consistency of electric and magnetic field exposures was tested by comparing chronaxie times for electric and magnetic PNS curves for 22 healthy human subjects. Electric and magnetic stimulation thresholds were measured for exposure of the forearm using both surface electrodes and a figure-eight magnetic coil, respectively. The average chronaxie times for the electric and magnetic field conditions were 109 ± 11 µs and 651 ± 53 µs (±SE), respectively. We do not propose that these results call into question the basic mechanism, namely that rapidly switched gradient magnetic fields induce electric fields in human tissues, resulting in PNS. However, this result does motivate us to suggest that special care must be taken when using electric field exposure data from the literature to set gradient coil PNS safety standards in MRI.

Recoskie, Bryan J.; Scholl, Timothy J.; Chronik, Blaine A.

2009-10-01

134

Dynamic multi-channel TMS with reconfigurable coil.  

PubMed

Investigations of the causal involvement of particular brain areas and interconnections in behavior require an external stimulation system with reasonable spatio-temporal resolution. Current transcranial magnetic stimulation (TMS) technology is limited to stimulating a single brain area once in a given trial. Here, we present a feasibility study for a novel TMS system based on multi-channel reconfigurable coils. With this hardware, researchers will be able to stimulate multiple brain sites in any temporal order in a trial. The system employs a wire-mesh coil, constructed using x- and y-directional wires. By varying the current direction and/or strength on each wire, we can configure the proposed mesh-wire coil into a standard loop coil and figure-eight coil of varying size. This provides maximum flexibility to the experimenter in that the location and extent of stimulation on the brain surface can be modified depending on experimental requirement. Moreover, one can dynamically and automatically modify the site(s) of stimulation several times within the span of seconds. By pre-storing various sequences of excitation patterns inside a control unit, one can explore the effect of dynamic TMS on behavior, in associative learning, and as rehabilitative therapy. Here, we present a computer simulation and bench experiments that show the feasibility of the dynamically-reconfigurable coil. PMID:23193321

Jiang, Ruoli; Jansen, Ben H; Sheth, Bhavin R; Chen, Ji

2013-05-01

135

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

136

Migratory shearwaters integrate oceanic resources across the Pacific Ocean in an endless summer  

PubMed Central

Electronic tracking tags have revolutionized our understanding of broad-scale movements and habitat use of highly mobile marine animals, but a large gap in our knowledge still remains for a wide range of small species. Here, we report the extraordinary transequatorial postbreeding migrations of a small seabird, the sooty shearwater, obtained with miniature archival tags that log data for estimating position, dive depth, and ambient temperature. Tracks (262 ± 23 days) reveal that shearwaters fly across the entire Pacific Ocean in a figure-eight pattern while traveling 64,037 ± 9,779 km roundtrip, the longest animal migration ever recorded electronically. Each shearwater made a prolonged stopover in one of three discrete regions off Japan, Alaska, or California before returning to New Zealand through a relatively narrow corridor in the central Pacific Ocean. Transit rates as high as 910 ± 186 km·day?1 were recorded, and shearwaters accessed prey resources in both the Northern and Southern Hemisphere’s most productive waters from the surface to 68.2 m depth. Our results indicate that sooty shearwaters integrate oceanic resources throughout the Pacific Basin on a yearly scale. Sooty shearwater populations today are declining, and because they operate on a global scale, they may serve as an important indicator of climate change and ocean health. PMID:16908846

Shaffer, Scott A.; Tremblay, Yann; Weimerskirch, Henri; Scott, Darren; Thompson, David R.; Sagar, Paul M.; Moller, Henrik; Taylor, Graeme A.; Foley, David G.; Block, Barbara A.; Costa, Daniel P.

2006-01-01

137

Optimal propulsive flapping in Stokes flows  

E-print Network

Swimming fish and flying insects use the flapping of fins and wings to generate thrust. In contrast, microscopic organisms typically deform their appendages in a wavelike fashion. Since a flapping motion with two degrees of freedom is able, in theory, to produce net forces from a time-periodic actuation at all Reynolds number, we compute in this paper the optimal flapping kinematics of a rigid spheroid in a Stokes flow. The hydrodynamics for the force generation and energetics of the flapping motion is solved exactly. We then compute analytically the gradient of a flapping efficiency in the space of all flapping gaits and employ it to derive numerically the optimal flapping kinematics as a function of the shape of the flapper and the amplitude of the motion. The kinematics of optimal flapping are observed to depend weakly on the flapper shape and are very similar to the figure-eight motion observed in the motion of insect wings. Our results suggest that flapping could be a exploited experimentally as a propul...

Was, Loic

2014-01-01

138

An All-Optical Access Metro Interface for Hybrid WDM/TDM PON Based on OBS  

NASA Astrophysics Data System (ADS)

A new all-optical access metro network interface based on optical burst switching (OBS) is proposed. A hybrid wavelength-division multiplexing/time-division multiplexing (WDM/TDM) access architecture with reflective optical network units (ONUs), an arrayed-waveguide-grating outside plant, and a tunable laser stack at the optical line terminal (OLT) is presented as a solution for the passive optical network. By means of OBS and a dynamic bandwidth allocation (DBA) protocol, which polls the ONUs, the available access bandwidth is managed. All the network intelligence and costly equipment is located at the OLT, where the DBA module is centrally implemented, providing quality of service (QoS). To scale this access network, an optical cross connect (OXC) is then used to attain a large number of ONUs by the same OLT. The hybrid WDM/TDM structure is also extended toward the metropolitan area network (MAN) by introducing the concept of OBS multiplexer (OBS-M). The network element OBS-M bridges the MAN and access networks by offering all-optical cross connection, wavelength conversion, and data signaling. The proposed innovative OBS-M node yields a full optical data network, interfacing access and metro with a geographically distributed access control. The resulting novel access metro architectures are nonblocking and, with an improved signaling, provide QoS, scalability, and very low latency. Finally, numerical analysis and simulations demonstrate the traffic performance of the proposed access scheme and all-optical access metro interface and architectures.

Segarra, Josep; Sales, Vicent; Prat, Josep

2007-04-01

139

The Ecogeomorphology of Salt Pools of the Webhannet Estuary, Wells, Maine, USA  

NASA Astrophysics Data System (ADS)

Salt pools are shallow, muddy depressions in salt marshes that remain flooded throughout the entire tidal cycle. They are common landforms of this ecosystem, but little is known for certain about their formation and persistence through time. Understanding the ontogeny of salt pools is critical, as it has been suggested that they may serve as important habitat for some birds and fish, and as indicators of ultimate marsh break-up and wetland loss. Hypotheses regarding pool initiation have suggested that pools are primary features of marshes, while others have suggested that pools form through secondary mechanisms such as isolated vegetative die-off or ice-plucking. Still others have suggested that pools may be associated with tidal creek abandonment. This study combines field observations, geologic coring, and analyses of a time-series of aerial photographs through geographic information systems (GIS), to quantify the recent history of pools of the Webhannet Estuary, Wells, ME, USA. Six transects sampled 119 pools during Summers 2004/2005. Adjacent percent vegetative cover (3, 1m2 plots/pool), bank classification (graded, mostly graded, mostly steep, steep), pool shape (circular, figure eight, irregular, sinuous) and a handheld GPS point were recorded. GPS data points were imported into a GIS platform to determine spatial trends. Examination of the spatial distribution suggests that pools are not randomly distributed across the marsh surface, but rather exhibit strong spatial patterns based on the pool characteristics described. Preliminary analyses of aerial photographs comparing the marsh surface in 1953 to 2003, suggest pools exhibit different developmental sequences over time (some grow, some shrink, some remain the same in area and shape). Dutch cores taken during Summer 2005 reveal a distinct pool signature and suggest that some pools may be of a more ephemeral nature than previously described and support the hypothesis that pools form through secondary mechanisms. New understanding of the development of salt pools may have practical management implications.

Wilson, K. R.; Kelley, J. T.

2005-12-01

140

Stationary equilibrium singularity distributions in the plane  

NASA Astrophysics Data System (ADS)

We characterize all stationary equilibrium point singularity distributions in the plane of logarithmic type, allowing for real, imaginary or complex singularity strengths. The dynamical system follows from the assumption that each of the N singularities moves according to the flow field generated by all the others at that point. For strength vector \\vec{\\Gamma} \\in {\\Bbb R}^N , the dynamical system is the classical point vortex system obtained from a singular discrete representation of the vorticity field from ideal, incompressible fluid flow. When \\vec{\\Gamma} \\in \\Im , it corresponds to a system of sources and sinks, whereas when \\vec{\\Gamma} \\in {\\Bbb C}^N the system consists of spiral sources and sinks discussed in Kochin et al (1964 Theoretical Hydromechanics 1 (London: Interscience)). We formulate the equilibrium problem as one in linear algebra, A \\vec{\\Gamma} = 0 , A \\in {\\Bbb C}^{N \\times N} , \\vec{\\Gamma} \\in {\\Bbb C}^N , where A is a N × N complex skew-symmetric configuration matrix which encodes the geometry of the system of interacting singularities. For an equilibrium to exist, A must have a kernel and \\vec{\\Gamma} must be an element of the nullspace of A. We prove that when N is odd, A always has a kernel, hence there is a choice of \\vec{\\Gamma} for which the system is a stationary equilibrium. When N is even, there may or may not be a non-trivial nullspace of A, depending on the relative position of the points in the plane. We provide examples of evenly and randomly distributed points on curves such as circles, figure eights, flower-petal configurations and spirals. We then show how to classify the stationary equilibria in terms of the singular spectrum of A.

Newton, P. K.; Ostrovskyi, V.

2012-02-01

141

Opposite Effects of High and Low Frequency rTMS on Mood in Depressed Patients: Relationship to Baseline Cerebral Activity on PET  

PubMed Central

Background Optimal parameters of rTMS for antidepressant efficacy in general, or within patients, have not been adequately delineated. Methods Using a double-blind, sham-controlled, cross-over design, 22 adult patients with treatment refractory major depression (n=9; bipolar disorder, depressed phase) were randomized to active rTMS (20-Hz or 1-Hz) or sham rTMS conditions and given 5 rTMS treatments per week for two weeks. Repetitive TMS was administered at 100% of motor threshold for 1600 pulses over the left prefrontal cortex using a figure-eight coil. Patients initially randomized to sham rTMS were then exposed to two weeks of active rTMS with each frequency under blinded conditions. Those who received active 20-Hz and 1-Hz rTMS were crossed over to the opposite frequency for two weeks. Improvement in Hamilton Depression ratings were assessed after each two-week treatment phase. PET imaging was used to evaluate the patient’s baseline absolute regional cerebral activity (blood flow and metabolism) as potential predictor of clinical response. Results Changes in depression severity on 1-Hz and 20-Hz rTMS were inversely correlated. PET scans with baseline hypoperfusion (but not hypometabolism) were associated with better improvement on 20-Hz rTMS as predicted. Limitations The magnitude of the clinical change with either frequency at 100% motor threshold was not robust, and larger studies with higher intensities of rTMS for longer durations of time should be explored. Conclusions High and low frequency rTMS exerts differential effects on depressed mood within individual subjects. The brain activity predictors and correlates of an optimal antidepressant response to rTMS remain to be better defined. PMID:19027962

Speer, A.M.; Benson, B.E.; Kimbrell, T.K.; Wassermann, E.M.; Willis, M.W.; Herscovitch, P.; Post, R.M.

2009-01-01

142

Movement strategies for maintaining standing balance during arm tracking in people with multiple sclerosis.  

PubMed

The purpose of this study was to quantify hip and ankle movement strategies during a standing arm tracking task in people with multiple sclerosis (MS). Full-body kinematics and kinetics were assessed with motion analysis cameras and force plates in nine MS and nine age-matched control subjects. While standing, participants used their dominant hand to track a target moving around a large horizontal or vertical figure eight on a screen in front of them. The target moved at constant speed, or linearly increasing speeds, with a frequency between 0.05 Hz and 0.35 Hz. Hip and ankle moments and angles during tracking were calculated from kinematic and kinetic measurements. Ratios of peak-to-peak (PP) hip/ankle moments (kinetics) and angles (kinematics) were calculated to determine the strategies of the hips and ankles used to maintain balance during arm movements. Center of mass (CoM) root mean square (RMS) acceleration was calculated as a measure of overall balance performance. The MS group produced larger PP hip/ankle moments at all speeds compared with the control group (P < 0.05). The CoM RMS acceleration increased with tracking speed for both groups but was not significantly different between groups. Additionally, the ratios of hip to ankle moments were highly correlated with the Berg Balance Scale during horizontal steady-speed tracking in MS. These results suggest that people with MS increase the use of the hip during standing arm tracking compared with age-matched control subjects. This adapted strategy might allow people with MS to achieve balance performance similar to control subjects, possibly increasing the importance of the hip in maintaining balance during voluntary movements. PMID:24966303

Chua, Matthew C; Hyngstrom, Allison S; Ng, Alexander V; Schmit, Brian D

2014-10-01

143

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

144

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, Francoise; Hoellinger, Thomas; Cebolla, Ana M.; Dan, Bernard; McIntyre, Joseph; Cheron, Guy

2014-01-01

145

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

146

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

147

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

148

A Channel for 3D Environmental Shape in Anterior Inferotemporal Cortex.  

PubMed

Inferotemporal cortex (IT) has long been studied as a single pathway dedicated to object vision, but connectivity analysis reveals anatomically distinct channels, through ventral superior temporal sulcus (STSv) and dorsal/ventral inferotemporal gyrus (TEd, TEv). Here, we report a major functional distinction between channels. We studied individual IT neurons in monkeys viewing stereoscopic 3D images projected on a large screen. We used adaptive stimuli to explore neural tuning for 3D abstract shapes ranging in scale and topology from small, closed, bounded objects to large, open, unbounded environments (landscape-like surfaces and cave-like interiors). In STSv, most neurons were more responsive to objects, as expected. In TEd, surprisingly, most neurons were more responsive to 3D environmental shape. Previous studies have localized environmental information to posterior cortical modules. Our results show it is also channeled through anterior IT, where extensive cross-connections between STSv and TEd could integrate object and environmental shape information. PMID:25242216

Vaziri, Siavash; Carlson, Eric T; Wang, Zhihong; Connor, Charles E

2014-10-01

149

Global seamless network demonstrator: carrier grade automatic switched transport network implementation in realistic telecom field environment  

NASA Astrophysics Data System (ADS)

The Global Seamless Network (GSN) Demonstrator is presented, a joint effort of system vendors and Deutsche Telekom Group R&D to demonstrate network functions and management integration and enable, for the first time, experiences with a carrier grade Automatically Switched Transport Network (ASTN) implementation and the envisaged main ASTN clients, IP and Ethernet. For end-to-end monitoring capability, integrating the view on the ASTN and Ethernet-MAN configuration, an UMS (Upper Monitoring System) is being developed. Furthermore broadband application were implemented to visualise the network functions. The ASTN backbone consists of four cross connects and an ULH-WDM system with 3x 10Gbit/s channels (OCh) between Berlin and Darmstadt, whereby each OCh is treated as a virtual fibre.

Foisel, Hans-Martin; Hanik, Norbert; Braun, Ralf-Peter; Lehr, Georg; Gladisch, Andreas

2004-04-01

150

Attack propagation of high-powered intrachannel crosstalk in transparent optical networks  

NASA Astrophysics Data System (ADS)

Transparent optical networks (TON) are becoming increasingly attractive, but transparency introduces security threats, e.g., intrachannel crosstalk attack, to optical networks. In this letter, three attack scenarios, i.e., attack propagation within an optical cross connect (OXC), the secondary attacker traverses successive OXCs and original attacker traverses successive OXCs, are investigated. The scenarios accompanied with gain competition attack are also simulated as comparison. Bit-error-rate (BER), and eye diagram penalties are estimated via VPItransMakerTM. Our work proved that the attack signal will propagate intrachannel crosstalk attack to successive three OXCs but with limited two stages of optical switches in each OXC. The BER will be somewhat higher in case gain competition attack exists. The results will be useful for future managing, planning, and designing on TONs.

Sun, Zeyu; Peng, Yunfeng; Long, Keping

2011-10-01

151

SDH over WDM: interworking and planning aspects  

NASA Astrophysics Data System (ADS)

The protection aspects represent a fundamental point in designing a modern transport network. For this reason, SDH technology was developed taking into maximum account the survivability requirements. The evolution of backbone transport network towards the WDM technology will have also to take into account these aspects. In particular this paper highlights the open issues to coordinate the interworking between the SDH and WDM network layer, the trade-off between transparency and manageability, and presents a possible evolution scenario of how WDM technology could integrate into SDH-based transport networks. The increasing installation of WDM systems from point to point system to multi wavelength optical ring and even to optical cross connect will force the definition of new planning and protection strategies.

Signorelli, Giulio D.; Gryseels, Michael; Demeester, Piet M. A.

1998-09-01

152

East-West fusion: cross-border human rights activism and the Thai Drug Users' Network.  

PubMed

Recently, international human rights leaders have renewed the call for advocacy on economic, social, and cultural rights and suggested partnerships with local organizations. The Thai Drug Users' Network (TDN) promotes the human rights of a marginalized and medically underserved population within Thailand. It also works internationally to reduce drugrelated harms. Thus, TDN transcends a strict local-international dichotomy. The group grew out of professional and personal ties between Thai drug users and international health and human rights actors. Border-crossing connections and two-way transfer of knowledge, particularly through bridging individuals or "cultural translators," have benefited both TDN and the non-Thai organizations that work with it. This case study shows how international-local, and even donor-recipient, relationships may be navigated in ways that are symbiotic and mutually empowering. PMID:17136908

Fink, Sheri

2005-01-01

153

Distributed Algorithm for Signal Polarity Adjustment of Air-Conditioner Control Network  

NASA Astrophysics Data System (ADS)

This paper proposes a distributed algorithm for adjusting the signal polarity of the control networks for building air-conditioners. As field connection work of the two wires to the controller may be straight or cross, each controller has both plus and minus polarity circuits. It starts the algorithm in the arbitary sequence, and then negociates each other to select the plus/minus polarity circuits in order to adjust the signal polarity. A Time Petri Net model was constructed for verification of the proposed algorithm. The model describes the required specification of the system, straight/cross connection of the controller to the network bus line and the polarity adjustment algorithm. The efficient Time Petri Net verification tool made it possible to verify the model.

Ninagawa, Chuzo; Aoi, Fumio; Yokohama, Koji; Yoneda, Tomohiro

154

Fully reconfigurable optical add/drop multiplexing subsystem on a chip  

NASA Astrophysics Data System (ADS)

We propose a single-chip-based module that provides the entire switching/monitoring/equalizing/shuffling functionality needed in 8-channel fully reconfigurable optical add/drop multiplexers. This subsystem on a chip includes an array of switches for adding/dropping individual channels, optical power taps and integrated photodetectors for power monitoring, variable optical attenuators for channel power equalization, and optical cross-connects for channel shuffling at the add and drop ports for full wavelength agility. The chip is based on a polymer-on-silicon platform that allows hybrid integration of passive and active elements. Waveguiding circuitry is built in an optical polymer, and it includes thermo-optic switches, variable optical attenuators, and power taps. Out-of-plane coupling mirrors are formed by ablation of 45° slopes in the polymer waveguides with an Excimer laser, followed by metalization. A self-aligning flipchip process is used to mount photodetector arrays on top of mirrors fabricated in tap waveguides for power monitoring. The worst-case fiber-to-fiber insertion loss for the proposed module, between 1528 and 1610 nm wavelength, is 1.2 dB from Input to Output (Express), including 4% tapped power, and 1.2 dB from Input to Drop and from Add to Output (4.1 dB with 8×8 shuffle cross-connects). The polarization dependent loss for any path is under 0.2 dB, and the polarization mode dispersion is under 0.05 ps. The channel-to-channel crosstalk is 50 dB, the switch extinction is 45 dB, and the return loss is 50 dB.

Eldada, Louay A.; Fujita, Junichiro; Radojevic, Antonije M.; Gerhardt, Reinald; Pant, Deepti; Wang, Fang; Xu, Chuck C.

2004-04-01

155

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

156

Modulation of amplitude and latency of motor evoked potential by direction of transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

The present study analyzed the effects of monophasic magnetic stimulation to the motor cortex. The effects of magnetic stimulation were evaluated by analyzing the motor evoked potentials (MEPs). The amplitude and latency of MEPs on the abductor pollicis brevis muscle were used to evaluate the effects of repetitive magnetic stimulation. A figure eight-shaped flat coil was used to stimulate the region over the primary motor cortex. The intensity of magnetic stimulation was 120% of the resting motor threshold, and the frequency of magnetic stimulation was 0.1 Hz. In addition, the direction of the current in the brain was posterior-anterior (PA) or anterior-posterior (AP). The latency of MEP was compared with PA and AP on initial magnetic stimulation. The results demonstrated that a stimulus in the AP direction increased the latency of the MEP by approximately 2.5 ms. MEP amplitude was also compared with PA and AP during 60 magnetic stimulations. The results showed that a stimulus in the PA direction gradually increased the amplitude of the MEP. However, a stimulus in the AP direction did not modulate the MEP amplitude. The average MEP amplitude induced from every 10 magnetic pulses was normalized by the average amplitude of the first 10 stimuli. These results demonstrated that the normalized MEP amplitude increased up to approximately 150%. In terms of pyramidal neuron indirect waves (I waves), magnetic stimulation inducing current flowing backward to the anterior preferentially elicited an I1 wave, and current flowing forward to the posterior elicited an I3 wave. It has been reported that the latency of the I3 wave is approximately 2.5 ms longer than the I1 wave elicitation, so the resulting difference in latency may be caused by this phenomenon. It has also been reported that there is no alteration of MEP amplitude at a frequency of 0.1 Hz. However, this study suggested that the modulation of MEP amplitude depends on stimulation strength and stimulation direction.

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

2014-05-01

157

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

158

Abdominoplasty and abdominal wall rehabilitation: a comprehensive approach.  

PubMed

Standard abdominoplasty techniques involve a low horizontal or W skin excision, muscle plication, and umbilical transposition. Newer techniques include suction-assisted lipectomy, the use of high lateral tension with fascial suspension, and external oblique muscle advancement. The author has modified these traditional procedures and added new techniques to improve the aesthetic and functional results of the abdominoplasty procedure. This modification provides a comprehensive approach to abdominal wall aesthetic improvement and rehabilitation. The comprehensive approach described includes four components: the "U-M dermolipectomy," "V umbilicoplasty," the rectus abdominis "myofascial release," and suction-assisted lipectomy. The patient is marked while standing for areas of suction lipectomy and undermining. The lower incision is designed as an open U with the lateral limbs placed inside the bikini line. The upper incision is a lazy M with the higher peaks located at the level of the flanks. Subcutaneous hydration is achieved to perform suction along the flanks, waistline, and iliac areas. Gentle suction of the flaps is also performed. The umbilicus is cored out in a heart shape. The flaps within the U-M marks are excised, and the undermining is performed to the xiphoid and costal margins. The rectus diastasis is marked, and the anterior rectus fascia is incised at the junction of the medial third with the central third of the width of the rectus sheath. Horizontal figure-eight plication sutures by using the lateral fascial edge enable easier infolding of the central tissue. The new recipient of the umbilicus is made by an incision in a V shape on the abdominal flap. The umbilicus is telescoped, and the triangular flap of the abdomen is sutured to the triangular defect of the umbilicus. Skin flap fixation to the umbilicus relieves tension in the lower portion of the flap. The upper skin flap, which is cut in an M manner, provides lateral tension and matches the length of the lower flap. A standard fascial suspension is used and closure is performed in layers. The techniques described here are intertwined procedures. Each facilitates the accomplishment of the other procedure, and they complement each other. They all attain the 12 objectives of the abdominoplasty described. These combined techniques have been used in 104 patients in a period of 11 years. Complications were minimal and easily manageable, except for one patient who required excision of a pseudobursa and retightening of the lower quadrants of the abdominal wall musculature to correct extreme lordosis. A comprehensive approach for the treatment of complex abdominal wall aesthetic and functional defects is presented. These require thoughtful integration of the four components mentioned. This approach has allowed predictable, reproducible, and aesthetically pleasing results. PMID:10627012

Ramirez, O M

2000-01-01

159

Computerized mapping of fibrillation in normal ventricular myocardium  

NASA Astrophysics Data System (ADS)

It is well known that the ability to fibrillate is intrinsic to a normal ventricle that exceeds a critical mass. The questions we address are how is ventricular fibrillation (VF) initiated and perpetuated in normal myocardium, and why is VF not seen more often in the general population if all ventricles have the ability to fibrillate. To study the mechanisms of VF, we used computerized mapping techniques with up to 512 channels of simultaneous multisite recordings for data acquisition. The data were then processed for dynamic display of the activation patterns and for mathematical analyses of the activation intervals. The results show that in normal ventricles, VF can be initiated by a single strong premature stimulus given during the vulnerable period of the cardiac cycle. The initial activations form a figure-eight pattern. Afterward, VF will perpetuate itself without any outside help. The self-perpetuation itself is due to at least two factors. One is that single wave fronts spontaneously break up into two or more wavelets. The second is that when two wavelets intersect perpendicular to each other, the second wavelet is broken by the residual refractoriness left over from the first wavelet. Mathematical analyses of the patterns of activation during VF revealed that VF is a form of chaos, and that transition from ventricular tachycardia (VT) to VF occurs via the quasiperiodic route. In separate experiments, we found that we can convert VF to VT by tissue size reduction. The physiological mechanism associated with the latter transition appears to be the reduction of the number of reentrant wave fronts and wandering wavelets. Based on these findings, we propose that the reentrant wave fronts and the wandering wavelets serve as the physiological equivalent of coupled oscillators. A minimal number of oscillators is needed for VF to perpetuate itself, and to generate chaotic dynamics; hence a critical mass is required to perpetuate VF. We conclude that VF in normal myocardium is a form of reentrant cardiac arrhythmia. A strong electrical stimulus initiates single or dual reentrant wave fronts that break up into multiple wavelets. Sometimes short-lived reentry is also generated during the course of VF. These organized reentrant and broken wavelets serve as coupled oscillators that perpetuate VF and maintain chaos. Although the ability to support these oscillators exists in a normal ventricle, the triggers required to generate them are nonexistent in the normal heart. Therefore, VF and sudden death do not happen to most people with normal ventricular myocardium.

Chen, Peng-Sheng; Garfinkel, Alan; Weiss, James N.; Karagueuzian, Hrayr S.

1998-03-01

160

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

2014-09-30

161

SHC-1/p52Shc targets the insulin/IGF-1 and JNK signaling pathways to modulate life span and stress response in C. elegans  

PubMed Central

Correlative evidence links stress, accumulation of oxidative cellular damage, and aging in several species. Genetic studies in species ranging from yeast to mammals revealed several pathways regulating stress response and life span, including caloric intake, mitochondrial respiration, insulin/IGF-1 (IIS), and JNK (c-Jun N-terminal kinase) signaling. How IIS and JNK signaling cross-talk to defend against diverse stressors contributing to aging is of critical importance but, so far, only poorly understood. In this study, we demonstrate that the adaptor protein SHC-1, the Caenorhabditis elegans homolog of human p52Shc, coordinates mechanisms of stress response and aging. Using genetic and biochemical approaches, we discover that SHC-1 not only opposes IIS but also activates JNK signaling. Loss of shc-1 function results in accelerated aging and enhanced sensitivity to heat, oxidative stress, and heavy metals, whereas expression of human p52Shc rescues the shc-1 mutant phenotype. SHC-1 acts upstream of the insulin/IGF receptor DAF-2 and the PI3 kinase AGE-1 and directly interacts with DAF-2. Moreover, SHC-1 activates JNK signaling by binding to MEK-1 kinase. Both aspects converge on controlling the nuclear translocation and activation of the FOXO transcription factor DAF-16. Our findings establish C. elegans SHC-1 as a critical scaffold that directly cross-connects the two parallel JNK and IIS pathways and help to explain how these signaling cascades cooperate to ascertain normal stress response and life span in C. elegans. PMID:18832074

Neumann-Haefelin, Elke; Qi, Wenjing; Finkbeiner, Elisabeth; Walz, Gerd; Baumeister, Ralf; Hertweck, Maren

2008-01-01

162

Cost Comparison of Fiber to the Home Topologies  

NASA Astrophysics Data System (ADS)

Topologies for economically bringing fiber to the home are under investigation. This paper examines the outside plant (OSP) costs of five different fiber to the home topologies and compares them to the cost of existing copper topology for the delivery of telephone service to the home. The costs were analyzed for a newly built subdivision. The topologies include, two fiber star, one fiber star, splitter-star, active pedestal, and bus. The costs examined are for fiber optic cable, hardware, and interconnect devices. Topology costs are calculated from current and projected prices for fiber optic components. The calculations for each topology include the components from the connector in the Central Office (CO) or Remote Terminal (RT) to the connector at the home or pedestal for the fiber system. The component parts include terminating equipment inside the CO or RT, feeder, distribution, and drop cables, splices, connectors, cross connect, taper hardware, and pedestals. Electronics (opto-electric conversion at CO/RT and pedestal/home) costs and installation costs are not included in the analysis. Addition of electronics and installation costs for each topology will allow telco planners to determine the overall topology cost. The analysis reveals the active pedestal and bus topologies as the most efficient deployment of OSP equipment and suitable economic candidates for fiber to the home systems in the near term. Splitter based systems become viable later on and one fiber systems are possible if additional revenue is available.

Pollock, Robert W.; Goessing, Peter E.

1990-01-01

163

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.

164

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

165

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

166

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

167

Greywater recycling systems in Germany--results, experiences and guidelines.  

PubMed

Although Germany is not considered a water-poor country, there exist regional differences in water supply and consumption. During the past 15 years, the greywater aspect has been dealt with in Germany with a greater interest and variable success. In addition to an increased environmental awareness, water costs also play an important role in increasing the demand for advanced greywater treatment plants nstalled in buildings. Under favourable conditions, the amortisation costs usually lie between 5 and 7 years. Systems that have been extensively tried and tested and have been shown to be most reliable are those employing an advanced biological treatment followed by an UV disinfection. Systems based on membrane technology are being developed and researched intensively in Germany for municipal wastewater treatment. However, so far they play no role in greywater recycling. Greywater systems operating under low energy and maintenance requirements without the use of chemicals are mostly favoured. In Germany, greywater recycling systems should be registered at the Health Office in order to guarantee that no cross-connections exist with the drinking water network and that pipes are labelled according to regulations. The hygienic requirements for recycled greywater, which is primarily used for toilet flushing, are oriented towards the EU-Guidelines for Bathing Waters. The use of recycled greywater for irrigation purposes is minor. As to the use of recycled water for laundry, the first promising investigation results are now available. PMID:16104423

Nolde, E

2005-01-01

168

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

169

Protection schemes with waveband grooming in fault-tolerant multidomain optical networks  

NASA Astrophysics Data System (ADS)

In wavelength-division-multiplexing networks, the fault-tolerance is very important since failures may lead to a significant amount of data loss. At the same time, the waveband switching technique is very interesting since it can save switching ports in optical cross-connections. In addition, the hierarchical routing in multidomain optical networks is very challenging since the interdomain routing is based on aggregative virtual topology. However, previous works did not jointly consider the three issues. We propose two schemes, segment-based protection (SBP) and path-based protection (PBP), to provide the fault-tolerance and waveband grooming in multidomain optical networks. In SBP, for each connection we first compute an interdomain loose route based on virtual topology, and then we compute the intradomain exact path-pairs in each single domain traversed by the loose route based on physical topology. In PBP, for each connection we first compute an interdomain loose primary path and an interdomain loose backup path based on virtual topology, and then we compute the intradomain exact paths in each single domain traversed by the loose primary path and backup path based on the physical topology. To support multidomain waveband grooming, we present the layered auxiliary graph. Simulation results show that PBP performs better than SBP.

Guo, Lei; Cao, Jiannong; Wang, Xingwei; Jiang, Dingde; Yang, Ting

2010-04-01

170

Death and transfiguration in static Staphylococcus epidermidis cultures.  

PubMed

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

171

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

172

Searching for storm water inflows in foul sewers using fibre-optic distributed temperature sensing.  

PubMed

A major drawback of separate sewer systems is the occurrence of illicit connections: unintended sewer cross-connections that connect foul water outlets from residential or industrial premises to the storm water system and/or storm water outlets to the foul sewer system. The amount of unwanted storm water in foul sewer systems can be significant, resulting in a number of detrimental effects on the performance of the wastewater system. Efficient removal of storm water inflows into foul sewers requires knowledge of the exact locations of the inflows. This paper presents the use of distributed temperature sensing (DTS) monitoring data to localize illicit storm water inflows into foul sewer systems. Data results from two monitoring campaigns in foul sewer systems in the Netherlands and Germany are presented. For both areas a number of storm water inflow locations can be derived from the data. Storm water inflow can only be detected as long as the temperature of this inflow differs from the in-sewer temperatures prior to the event. Also, the in-sewer propagation of storm and wastewater can be monitored, enabling a detailed view on advection. PMID:24185052

Schilperoort, Rémy; Hoppe, Holger; de Haan, Cornelis; Langeveld, Jeroen

2013-01-01

173

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

174

Managing risks from virus intrusion into water distribution systems due to pressure transients.  

PubMed

Low or negative pressure transients in water distribution systems, caused by unexpected events (e.g. power outages) or routine operation/maintenance activities, are usually brief and thus are rarely monitored or alarmed. Previous studies have shown connections between negative pressure events in water distribution systems and potential public health consequences. Using a quantitative microbial risk assessment (QMRA) model previously developed, various factors driving the risk of viral infection from intrusion were evaluated, including virus concentrations external to the distribution system, maintenance of a disinfectant residual, leak orifice sizes, the duration and the number of nodes drawing negative pressures. The most sensitive factors were the duration and the number of nodes drawing negative pressures, indicating that mitigation practices should be targeted to alleviate the severity of low/negative pressure transients. Maintaining a free chlorine residual of 0.2 mg/L or above is the last defense against the risk of viral infection due to negative pressure transients. Maintaining a chloramine residual did not appear to significantly reduce the risk. The effectiveness of ensuring separation distances from sewer mains to reduce the risk of infection may be system-specific. Leak detection/repair and cross-connection control should be prioritized in areas vulnerable to negative pressure transients. PMID:21942194

Yang, Jian; LeChevallier, Mark W; Teunis, Peter F M; Xu, Minhua

2011-06-01

175

State-dependent computation using coupled recurrent networks.  

PubMed

Although conditional branching between possible behavioral states is a hallmark of intelligent behavior, very little is known about the neuronal mechanisms that support this processing. In a step toward solving this problem, we demonstrate by theoretical analysis and simulation how networks of richly interconnected neurons, such as those observed in the superficial layers of the neocortex, can embed reliable, robust finite state machines. We show how a multistable neuronal network containing a number of states can be created very simply by coupling two recurrent networks whose synaptic weights have been configured for soft winner-take-all (sWTA) performance. These two sWTAs have simple, homogeneous, locally recurrent connectivity except for a small fraction of recurrent cross-connections between them, which are used to embed the required states. This coupling between the maps allows the network to continue to express the current state even after the input that elicited that state is withdrawn. In addition, a small number of transition neurons implement the necessary input-driven transitions between the embedded states. We provide simple rules to systematically design and construct neuronal state machines of this kind. The significance of our finding is that it offers a method whereby the cortex could construct networks supporting a broad range of sophisticated processing by applying only small specializations to the same generic neuronal circuit. PMID:19431267

Rutishauser, Ueli; Douglas, Rodney J

2009-02-01

176

Real-time monitoring of river water quality using in-line continuous acquisition of fluorescence excitation and emission matrices  

NASA Astrophysics Data System (ADS)

In-line fluorescence EEM monitoring has been performed over an eleven-day period for Bournbrook River, Birmingham, UK. River water was diverted to a portable laboratory via a continuous flow pump and filter system. Fluorescence excitation-emission matrices data was recorded every 3 minutes using a flow cell (1cm pathlength) coupled to a fiber optic probe. This real-time fluorescence EEM data (Excitation, 225-400 nm at 5 nm steps, emission, 280-500 nm at 2 nm steps) was collected 'in-line'and directly compared with the spectrophotometric properties and physical and chemical parameters of river water samples collected off-line at known time intervals. Over the monitoring period, minor pollution pulses from cross connections were detected and identified hourly along with a random diesel pollution event. This work addresses the practicalities of measuring and detecting fluorescence EEM in the field and discusses the potential of this technological approach for further understanding important hydrological and biogeochemical processes. Problems associated with fouling and system failure are also reported. Example of the data generated from the continuous fluorescence EEM monitoring.

Carstea, E.; Baker, A.; Johnson, R.; Reynolds, D. M.

2009-12-01

177

Design and Implementation of a RF Powering Circuit for RFID Tags or Other Batteryless Embedded Devices  

PubMed Central

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

178

Termination of supraspinal descending pathways in the spinal cord of the tegu lizard, Tupinambis nigropunctatus.  

PubMed

Descending fiber projections to the lizard spinal cord were studied using anterograde axonal degeneration. Following hemisection of the cord at the first spinal segment, degeneration was found in the white and gray matter as far down as the 31st (caudal) segment. Degenerating fibers in the white matter were confined to the ipsilateral side and were found in the medial longitudinal fasiculus and the outer half ot the lateral and ventral funiculi. Degeneration was more intense in the dorsolateral and ventromedial funiculi than in the ventrolateral funiculus. In the gray matter, REXED's criteria were applied to Nissl-stained material to delimit boundaries of ten laminae. Degeneration of suprospinal axons was most intense in the medial part of VII, dorsal and ventral commissures to ramify contralaterally in the medial part of VII, in VII, and in medial IX. No degeneration was present in the lateral part of the spinal gray on the contralateral side. In Golgi-stained material, dendrites of lateral IX cells were seen to extend into lamina VII, the dorsolateral part of VII, and the lateral funiculus. Thus, fibers of the ventromedial supraspinal pathway may make axodendritic contact with motoneurons of lateral IX as well as medial IX, ipsilaterally. In addition, there is a possibility of a crossed connection to contralateral motoneurons. PMID:1225465

Cruce, W L

1975-01-01

179

Evaluation of steel shafts for magnetostrictive torque sensors (abstract)  

NASA Astrophysics Data System (ADS)

Based on the magnetostrictive effect in steel, a robust, noncontacting shaft torque sensor can be obtained. A fundamental problem in this scheme is compatibility between mechanical strength required for a shaft and a magnetic one needed for a torque sensor. In order to find shaft material accommodating these two requirements, we investigated basic characteristics, such as hysteresis, linearity, and zero-level fluctuation associated with shaft rotation, of the magnetostrictive torque sensor for various nickel chromium molybdenum steel shafts (SNCM in Japanese Industrial Standard) subjected to case hardening. We prepared three kinds of shafts of 25 mm in diameter: SNCM 420 (Ni=1.69%, C=0.2%), SNCM 616 (Ni=2.91%, C=0.15%), and SNCM 447 (Ni=1.67%, C=0.49%). Shafts of the first two materials were carburized, whereas those of the last one were quenched. We used a magnetic head-type torque sensor consisting of a pair of cross-coupled figure-eight coils (14 turn), which has been already proposed by us.1 The hysteresis in the input-output relationship was measured for the excitation current from 0.1 to 1.0 A at the excitation frequency of 60 kHz. The hysteresis of the SNCM 420 shaft changes sign from negative to positive with the increase in excitation current and that of the SNCM 616 shaft decreases monotonically but never reaches zero, whereas that of the SNCM 447 shaft exhibits minimum. The smallest values obtained are nearly zero for the SNCM 420 shaft at 0.3 A, 1.5%/(full scale (FS)=400 Nm) for the SNCM 616 shaft at 1.0 A and 0.7%/FS for the SNCM 447 shaft at 0.8 A, respectively. The linearity measured for the SNCM 420 shaft, which has the smallest hysteresis of the three, at 0.3 A and 60 kHz was virtually straight for the applied torque range -400-400 Nm and 0.8% of nonlinearity error for the range -1000-1000 Nm. The zero-level fluctuation was measured for the SNCM 420 shaft by rotating the shaft without applying torque. The level of the fluctuation was as small as ±1.8%/FS (FS=1000 Nm). It is interesting to consider the effect of carburization on the performance of the shaft seen from the torque sensor. The sensitivity of the as-ground SNCM 420 shaft is approximately ten times larger than that of carburized shafts, however, the input-output relationship measured for the as-ground shaft was saturated completely at the applied torque of 400 Nm. The zero-level fluctuation for the as-ground shaft was about the same in terms of %/FS as that of carburized shaft. Considering that the reduction of the sensitivity by carburization is a factor of 10, magnetic inhomogeneities at the surface are well improved by the carburizing process. We measured the two-dimensional pattern of magnetic anisotropy distribution by scanning the shaft surface using a 6.5 mm square eddy current probe that is sensitive to magnetic anisotropy.2 We found that the as-ground shaft has a peculiar magnetic anisotropy pattern, which is probably induced during manufacturing steel bars. The pattern was erased by the heat treatment at 920 °C for 4 h, which is a main course of carburization treatment.

Koga, F.; Yoshida, K.; Sasada, I.

1997-04-01

180

Quantifying Urban Water Subsidies with Hydrological Tracers of Domestic Water  

NASA Astrophysics Data System (ADS)

Connections between urban hydrological systems and human water infrastructure are well established. Interactions between these systems occur at a wide range of scales, from large inter-basin transfers to individual leaking pipes. However, much of the interest in these connections arises from practical considerations, for example, substantially altered in-stream flow or the presence/absence of sewage in surface water systems. Less recognized is that in smaller urban catchments, daily water flux through human water distribution systems is often much larger than low flow surface water flux from the catchment. As infrastructure ages and cross-connections grow, transfers from the substantial human fluxes to the catchment will increasingly subsidize urban water budgets. Tools for quantifying the contribution of this subsidy to urban hydrological systems can clarify both practical questions for urban managers and our understanding of flow generation in catchments. Stream water chemistry from a multi-year sampling campaign in Nine Mile Run (Pittsburgh, PA) is used to examine potential hydrological tracers of human domestic water. In particular, we examine the use of fluoride added in precise quantities as a dental health supplement as a tracer of human domestic water (e.g., drinking and waste water). While fluoride is not necessarily a conservative tracer, equilibrium reactions governing fluoride solubility generally require substantially higher cationic concentrations than those observed in surface water chemistry. Further, during periods where human subsidies dominate (e.g., water line breaks or hydrant flushes discharging to the stream) fluoride concentrations generally approach the concentration added to domestic water. We use multiple modeling approaches to demonstrate the appropriateness of fluoride as a tracer, infer contributions of human domestic water to the hydrologic budget, and explore fluoride dynamics in the Nine Mile Run basin. A fluoride tracer is particularly exciting due to applicability in a large number of urban systems fluoridating drinking waters and due to robust, high-frequency measurement capacity via off-the-shelf drinking water treatment technologies.

Bain, D. J.; Sikora, M. T.; Wozniak, E.; Fisher, K. R.; Carr, J.; Elliott, E. M.

2011-12-01

181

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

182

Fanconi anemia core complex gene promoters harbor conserved transcription regulatory elements.  

PubMed

The Fanconi anemia (FA) gene family is a recent addition to the complex network of proteins that respond to and repair certain types of DNA damage in the human genome. Since little is known about the regulation of this novel group of genes at the DNA level, we characterized the promoters of the eight genes (FANCA, B, C, E, F, G, L and M) that compose the FA core complex. The promoters of these genes show the characteristic attributes of housekeeping genes, such as a high GC content and CpG islands, a lack of TATA boxes and a low conservation. The promoters functioned in a monodirectional way and were, in their most active regions, comparable in strength to the SV40 promoter in our reporter plasmids. They were also marked by a distinctive transcriptional start site (TSS). In the 5' region of each promoter, we identified a region that was able to negatively regulate the promoter activity in HeLa and HEK 293 cells in isolation. The central and 3' regions of the promoter sequences harbor binding sites for several common and rare transcription factors, including STAT, SMAD, E2F, AP1 and YY1, which indicates that there may be cross-connections to several established regulatory pathways. Electrophoretic mobility shift assays and siRNA experiments confirmed the shared regulatory responses between the prominent members of the TGF-? and JAK/STAT pathways and members of the FA core complex. Although the promoters are not well conserved, they share region and sequence specific regulatory motifs and transcription factor binding sites (TBFs), and we identified a bi-partite nature to these promoters. These results support a hypothesis based on the co-evolution of the FA core complex genes that was expanded to include their promoters. PMID:21826217

Meier, Daniel; Schindler, Detlev

2011-01-01

183

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

184

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

185

Posttranslational Maturation of the Invasion Acyl Carrier Protein of Salmonella enterica Serovar Typhimurium Requires an Essential Phosphopantetheinyl Transferase of the Fatty Acid Biosynthesis Pathway  

PubMed Central

Salmonella pathogenicity island 1 (SPI-1) carries genes required for the formation of a type 3 secretion system, which is necessary for the invasion process of Salmonella. Among the proteins encoded by SPI-1 is IacP, a homolog of acyl carrier proteins. Acyl carrier proteins are mainly involved in fatty acid biosynthesis, and they require posttranslational maturation by addition of a 4?-phosphopantetheine prosthetic group to be functional. In this study, we analyzed IacP maturation in vivo. By performing matrix-assisted laser desorption ionization–time-of-flight (MALDI-TOF) mass spectrometry analysis of intact purified proteins, we showed that IacP from Salmonella enterica serovar Typhimurium was matured by addition of 4?-phosphopantetheine to the conserved serine 38 residue. Therefore, we searched for the phosphopantetheinyl transferases in charge of IacP maturation. A bacterial two-hybrid approach revealed that IacP interacted with AcpS, an enzyme normally required for the maturation of the canonical acyl carrier protein (ACP), which is involved in fatty acid biosynthesis. The creation of a conditional acpS mutant then demonstrated that AcpS was necessary for the maturation of IacP. However, although IacP was similar to ACP and matured by using the same enzyme, IacP could not replace the essential function of ACP in fatty acid synthesis. Hence, the demonstration that IacP is matured by AcpS establishes a cross-connection between virulence and fatty acid biosynthesis pathways. PMID:23893113

Puppo, Remy; My, Laetitia; Bouveret, Emmanuelle

2013-01-01

186

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

187

[Pollution and retro-pollution by the distribution system of medical gases].  

PubMed

The anaesthetic machine, the recovery room or the ICU ventilator as well as any other simple oxygenation device can be accidentally supplied with a "wrong" gas, or a mixture of "wrong" and "true" gases, or a gas containing chemical impurities, as a result of one of the following causes: a) the source of the medical gas pipeline supply contains a "wrong" gas or impurities; b) the gas pipeline is polluted by a "wrong" gas or solvents, introduced during the installation or maintenance of the pipeline; c) the pipeline is polluted by a wrong gas at a point of inter-connection or cross-connection of two pipelines; d) supply of a "wrong" gas through wrong quick couplers connected to the pipeline; e) back flow of a gas in another pipeline supply through a defective gas mixer, which is today the most common cause of pipeline contamination or retropollution. It occurs with some types of mixers in case of absence or malfunction of non-return valves, associated with a pressure difference between the two gas lines. The means of prevention, recognition and emergency treatment of these events include: a) systematic removal of mixers and flowmeter-mixers from supplies when not in use; b) periodical checking of these devices for an accidental communication between the gases to be mixed; c) systematic use of an oxygen analyser for a continuous measurement of FIO2, especially when the machine is connected to the N2O pipeline supply; d) the presence of a reserve cylinder of oxygen connected to every anaesthetic machine. PMID:7733522

Otteni, J C; Ancellin, J; Cazalaà, J B; Clergue, F

1994-01-01

188

Assessment of drinking water quality using ICP-MS and microbiological methods in the Bholakpur area, Hyderabad, India.  

PubMed

A total of 16 people died and over 500 people were hospitalized due to diarrhoeal illness in the Bholakpur area of Hyderabad, India on 6th May 2009. A study was conducted with immediate effect to evaluate the quality of municipal tap water of the Bholakpur locality. The study consists of the determination of physico-chemical properties, trace metals, heavy metals, rare earth elements and microbiological quality of drinking water. The data showed the variation of the investigated parameters in samples as follows: pH 7.14 to 8.72, EC 455 to 769 ?S/cm, TDS 303.51 to 515.23 ppm and DO 1.01 to 6.83 mg/L which are within WHO guidelines for drinking water quality. The water samples were analyzed for 27 elements (Li, Be, B, Na, Mg, Al, Si, K, Ca, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Ba and Pb) using inductively coupled plasma-mass spectrometry (ICP-MS). The concentrations of Fe (0.12 to 1.13 mg/L), Pb (0.01 to 0.07 mg/L), Cu (0.01 to 0.19 mg/L), Ni (0.01 to 0.15 mg/L), Al (0.16 to 0.49 mg/L), and Na (38.36 to 68.69 mg/L) were obtained, which exceed the permissible limits of the World Health Organization (WHO) for drinking water quality guidelines. The remaining elements were within the permissible limits. The microbiological quality of water was tested using standard plate count, membrane filtration technique, thermotolerant coliform (TTC), and most probable number (MPN) methods. The total heterotrophic bacteria ranged from 1.0 × 10(5) to 18 × 10(7 )cfu/ml. Total viable bacteria in all the water samples were found to be too numerable to count and total number of coliform bacteria in all water samples were found to be of order of 1,100 to >2,400 MPN index/100 ml. TTC tested positive for coliform bacteria at 44.2°C. All the water samples of the study area exceeded the permissible counts of WHO and that (zero and minimal counts) of the control site (National Geophysical Research Institute) water samples. Excessively high colony numbers indicate that the water is highly contaminated with microorganisms and is hazardous for drinking purposes. Bacteriological pollution of drinking water supplies caused diarrhoeal illness in Bholakpur, which is due to the infiltration of contaminated water (sewage) through cross connection, leakage points, and back siphoning. PMID:21544503

Abdul, Rasheed M; Mutnuri, Lakshmi; Dattatreya, Patil J; Mohan, Dayal A

2012-03-01

189

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

NASA Astrophysics Data System (ADS)

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 been the multi-scale nature of the problem: a narrow boundary layer, ``the dissipation region,'' breaks field lines and controls the release of energy in a macroscale system. Significant progress has been made on fundamental questions such as how magnetic energy is released so quickly and why the release occurs as an explosion. At the small spatial scales of the dissipation region the motion of electrons and ions decouples, the MHD description breaks down and whistler and kinetic Alfven dynamics drives reconnection. The dispersive property of these waves leads to fast reconnection, insensitive to system size and weakly dependent on dissipation, consistent with observations. The evidence for these waves during reconnection in the magnetosphere and the laboratory is compelling. The role of turbulence within the dissipation region in the form of ``secondary islands'' or as a source of anomalous resistivity continues to be explored. A large fraction of the magnetic energy released during reconnection appears in the form of energetic electrons and protons -- up to 50% or more during solar flares. The mechanism for energetic particle production during magnetic reconnection has remained a mystery. Models based on reconnection at a single large x-line are incapable of producing the large numbers of energetic electrons seen in observations. Scenarios based on particle acceleration in a multi-x-line environment are more promising. In such models a link between the energy gain of electrons and the magnetic energy released, a requirement to explain the observations, has been established. The talk will review key observational data and emphasize basic physical principles to introduce the topic to the non-specialist.[4pt] Thanks to the many colleagues who have contributed to this work. This work was supported by DOE, NASA and NSF.

Drake, James

2010-11-01

190

Analysis of elemental concentration using ICP-AES and pathogen indicator in drinking water of Qasim Abad, District Rawalpindi, Pakistan.  

PubMed

The present study was conducted to investigate drinking water quality (groundwater) from water samples taken from Qasim Abad, a locality of approximately 5,000 population, situated between twin cities Rawalpindi and Islamabad in Pakistan. The main sources of drinking water in this area are water bores which are dug upto the depth of 250-280 ft in almost every house. The study consists of the determination of physico-chemical properties, trace metals, heavy metals, rare earth elements and microbiological quality of drinking water. The data showed the variation of the investigated parameters in samples as follows: pH 6.75 to 8.70, electrical conductivity 540 to 855 ?S/cm, total dissolved solids 325.46 to 515.23 ppm and dissolved oxygen 1.50 to 5.64 mg/L which are within the WHO guidelines for drinking water quality. The water samples were analysed for 30 elements (aluminium, iron, magnesium, manganese, silicon, zinc, molybdenum, titanium, chromium, nickel, tungsten, silver, arsenic, boron, barium, beryllium, cadmium, cobalt, copper, gallium, mercury, lanthanum, niobium, neodymium, lead, selenium, samarium, tin, vanadium and zirconium) by using inductively coupled plasma atomic emission spectroscopy. The organic contamination was detected in terms of most probable number (MPN) of faecal coliforms. Overall, elemental levels were lower than the recommended values but three water bores (B-1, B-6, B-7) had higher values of iron (1.6, 2.206, 0.65 ppm), two water bores (B-1, B-6) had higher values of aluminium (0.95, 1.92 ppm), respectively, and molybdenum was higher by 0.01 ppm only in one water bore (B-11). The total number of coliforms present in water samples was found to be within the prescribed limit of the WHO except for 5 out of 11 bore water samples (B-2, B-3, B-4, B-8, B-11), which were found in the range 5-35 MPN/100 mL, a consequence of infiltration of contaminated water (sewage) through cross connection, leakage points and back siphoning. PMID:22544071

Sehar, Shama; Naz, Iffat; Ali, Naeem; Ahmed, Safia

2013-02-01

191

BOOK REVIEW: Equations of Motion in General Relativity Equations of Motion in General Relativity  

NASA Astrophysics Data System (ADS)

Devoted exclusively to the problem of motion in general relativity, this book by H. Asada, T. Futamase, and P. A. Hogan is highly welcome to close up a gap in the book sector presenting a concise account of theoretical developments and results on gravitational equations of motion achieved since the discovery of the binary neutron star system PSR 1913+16 in 1974. For the most part, the book is concerned with the development and application of the important post-Newtonian approximation (PNA) framework which allows for highly efficient approximate analytic solutions of the Einstein field equations for many-body systems in terms of a slow-motion and weak-field ordering parameter. That approximation scheme is shown to be applicable also to the external motion of strongly self-gravitating objects if their internal dynamics is frozen in (strong field point particle limit) and the external conditions fit. Relying on the expertise of the authors, the PNA framework is presented in a form which, at the 1PNA level, had become famous through the work by Einstein, Infeld and Hoffmann in 1938; therein, surface integrals over gravitational field expressions in the outside-body regime play a crucial role. Other approaches which also succeeded with the highest achieved PNA level so far are mentioned too, if not fully exhaustively with respect to the highest, the 3.5PNA level which contains the inverse power of the speed of light to the seventh order. Regarding the 3PNA, the reader gains a clear understanding of how the equations of motion for binary systems with compact components come about. Remarkably, no deviation from four-dimensional space-time is needed. Various explicit analytic expressions are derived for binary systems: the periastron advance and the orbital period at the 2PNA, the orbital decay through gravitational radiation reaction at the 2.5PNA, and effects of the gravitational spin-orbit and spin-spin couplings on the orbital motion. Also the propagation of light-like signals in gravitational fields of binary systems is treated, which is important for a precise interpretation of pulsar observation measurements. Based on original research by the authors, a detailed presentation is given of a mathematical scheme which makes feasible the treatment of small black holes in background space-times. Using that approach, the equations of motion of small charged black holes are derived in vacuum Einstein-Maxwell space-times without encountering infinities, showing up electromagnetic radiation reaction, background field, and tail forces. At this stage, the book defines various issues to be tackled in future research within the given formalism, such as a physical understanding of the very structure of the tail contribution or a more detailed calculation of the motion of a small Schwarzschild black hole in an external vacuum gravitational field. A unique chapter is devoted to the choreographic three-body solution of the 1PNA dynamics, also mentioning the 2PNA dynamics, in the form of figure-eight configurations. The emitted gravitational waves are shown, and a discussion of their observability in future gravitational wave astronomy is given. Four appendices support and complement the main part of the book. Here, the far zone non-contribution to the equations of motion at 3PNA is carefully investigated, forces resulting from the extendedness of objects are presented in analytic form, null geodesic congruences with their optical scalars are discussed, and the perturbed vacuum Einstein-Maxwell field equations are given. The book delivers a very readable account of the problem of motion in general relativity. It covers the state of the art up to the years 2006/8 and presents a plethora of interesting and important topics and results. Whenever appropriate, connection with observation is made. A reader with good post-introductory knowledge of the theory of general relativity should find easy access to the book, and will surely benefit from the mathematical and conceptual issues elaborated on therein. Being of observational relevance too, the

Schäfer, Gerhard

2012-03-01