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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

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

Federal Register 2010, 2011, 2012, 2013, 2014

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

2013-05-02

5

Eccentric figure-eight coils for transcranial magnetic stimulation.  

PubMed

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

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

2015-01-01

6

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...

7

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

NASA Astrophysics Data System (ADS)

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

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

2003-05-01

8

Narrow-linewidth mode-lock figure-eight nanosecond pulse fiber laser  

NASA Astrophysics Data System (ADS)

A new figure-eight mode-lock laser design based on a passive nonlinear loop mirror with a small modulation depth has been proposed. Self-started narrow-linewidth nanosecond-pulse lasers are realized: one is based on polarization-insensitive components (with a polarization controller) and the other is an environmentally stable adjustment-free laser based on polarization-maintaining components. In both cases, the lasers generate rectangular-shaped pulses. The duration of the pulses can be continuously adjusted from sub-nanosecond to more than tens of nanoseconds by simply changing the pump power.

Likhachev, M. E.; Aleshkina, S. S.; Bubnov, M. M.

2014-12-01

9

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

10

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

11

Water Treatment Technology - Cross-Connections.  

ERIC Educational Resources Information Center

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

Ross-Harrington, Melinda; Kincaid, G. David

12

Generation of a noiselike soliton molecule induced by a comb filter in a figure-eight fiber laser  

NASA Astrophysics Data System (ADS)

We report on the generation of a noiselike soliton molecule induced by a comb filter in a figure-eight fiber laser. Despite the noiselike mode-locked operation, there were always several peaks riding on a wide shoulder when the mode-locked operation was obtained; this phenomenon was called the noiselike soliton molecule. It was found that the formation of the noiselike soliton molecule is induced by the intracavity comb filter. The observed results would give further insight towards understanding both the fundamental physics of soliton molecules and the noiselike pulses in passively mode-locked fiber lasers.

Luo, Ai-Ping; Zheng, Xu-Wu; Liu, Meng; Liu, Hao; Zhao, Nian; Ning, Qiu-Yi; Luo, Zhi-Chao; Xu, Wen-Cheng

2015-04-01

13

CROSS-CONNECTIONS COLLEGE OF LAW  

E-print Network

regarding income tax matters. >> The Securities Arbitration and Consumer Law Clinic provides legalCROSS-CONNECTIONS COLLEGE OF LAW At Syracuse University, we believe that the complexities of the world must be understood from multiple perspectives. In that context, the College of Law builds bridges

McConnell, Terry

14

Generation and characterization of erbium-Raman noise-like pulses from a figure-eight fibre laser  

NASA Astrophysics Data System (ADS)

We report an experimental study of the noise-like pulses generated by a ~300?m long passively mode-locked erbium-doped figure-eight fibre laser. Non-self-starting mode locking yields the formation of ns scale bunches of sub-ps pulses. Depending on birefringence adjustments, noise-like pulses with a variety of temporal profiles and optical spectra are obtained. In particular, for some adjustments the Raman-enhanced spectrum reaches a 10?dB bandwidth of ~130?nm. For the first time to our knowledge, we extract information on the inner structure of the noise-like pulses, using a birefringent Sagnac interferometer as a spectral filter and a nonlinear optical loop mirror as an intensity filter. In particular we show that the different spectral components of the bunch are homogeneously distributed within the temporal envelope of the bunch, whereas the amplitude and/or the density of the sub-pulses present substantial variations along the envelope. In some cases, the analysis reveals the existence of an intermediate level of organization in the structure of the noise-like pulse, between the ns bunch and the sub-ps inner pulses, suggesting that these objects may be even more complex than previously recognized.

Santiago-Hernandez, H.; Pottiez, O.; Paez-Aguirre, R.; Ibarra-Villalon, H. E.; Tenorio-Torres, A.; Duran-Sanchez, M.; Ibarra-Escamilla, B.; Kuzin, E. A.; Hernandez-Garcia, J. C.

2015-04-01

15

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

16

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

17

Dual-keel electrodynamic maglev system  

DOEpatents

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

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

1996-12-24

18

Dual-keel electrodynamic maglev system  

DOEpatents

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

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

1996-01-01

19

Cross-connection control of the potable water lines at Oak Ridge National Laboratory  

SciTech Connect

A 1991 independent U.S. Department of Energy (DOE) audit of Oak Ridge National Laboratory (ORNL) identified the need for establishing a cross-connection control program for the potable and nonpotable water systems at the facility. An informal cross-connection policy had been in place for some time, but the formal implementation of a cross-connection program brought together individuals from the Quality Engineering and Inspection Section of the Office of Quality Programs and Inspection, Industrial Hygiene, Health Physics, Plant and Equipment Division, and the Atomic Trade and Labor Council. In January 1994 a Cross-Connection Control Committee was established at ORNL to identify potential and actual cross connections between potable and nonpotable water systems. Potable water is safe to drink, and nonpotable or process water (e.g., sewage, laboratory wastewater, cooling water, and tower water) is not intended for human consumption, washing of the body, or food preparation. The program is intended to conform with the Federal Safe Drinking Water Act Amendment of 1986 and with state and local regulations. Although the Occupational Safety and Health Administration addresses cross-connection functions, it does not define specific program requirements. The program at ORNL is designed to ensure that necessary recommendations are implemented to safeguard all internal and external potable water distribution lines. Program responsibilities include a thorough engineering assessment to (1) identify the potable water lines, (2) identify any existing or potential cross connections, and (3) inspect the integrity of the water lines. If any cross-connection deficiencies are found, corrective actions are initiated according to industry standards.

Moore, R.M.

1996-04-01

20

Dynamically selective multiwavelength cross-connect based on fibre Bragg gratings and mechanical optical switches  

Microsoft Academic Search

A dynamically selective multiwavelength cross-connect for wavelength division multiplexed (WDM) networks based on fibre Bragg gratings (FBGs) and optical switches is reported. Dynamically single- or multi-channel cross-connect functionality can be realized according to control of the optical switches and the FBGs' arrangement. Bit-error-rate performance with negligible power penalty is achieved in a 2.5Gbs-1x3 WDM channels over 100km conventional single-mode fibre

YUNG-KUANG CHEN; SHIEN-KUEI LIAW; CHIEN-CHUNG LEE

1998-01-01

21

Densely packed NxN wavelength cross-connect switch module  

NASA Astrophysics Data System (ADS)

A wavelength cross-connect switch (WXC) is proposed and demonstrated. The cross-connect optics have orthogonal imaging systems that operate differently in the switching and spectral planes. The switching plane has 2f Fourier optics with a Rayleigh length. On the other hand, the spectral plane has 4f imaging optics. Two types of switching engines, microelectromechanical system (MEMS) mirrors and liquid crystal on silicon (LCOS), are applied for the same cross-connect optics. The 5×5 WXC with MEMS mirrors has a 100 GHz channel spacing, which is compatible with the International Telecommunication Union (ITU) grid. On the other hand, the WXC with LCOS has a variable channel spacing. The characteristics of two types of WXC are compared. In addition, the port count, which is one of the important parameters, is discussed.

Uetsuka, Hisato; Tachikura, Masao; Kawashima, Hitoshi; Ikeda, Kazuhiko; Sorimoto, Keisuke; Tsuda, Hiroyuki; Sasaki, Keiichi; Yamashita, Yuto

2015-01-01

22

Dynamic multi-path WDM routing in a monolithically integrated 8 × 8 cross-connect.  

PubMed

We demonstrate for the first time WDM multi-path routing through a monolithically integrated InP/InGaAsP 8 × 8 space and wavelength selective cross-connect. Data channels are dynamically routed from four input ports to the same output port with excellent OSNR from 27.0 to 31.1 dB. Representative data paths are evaluated in terms of optical power penalty. Data routing experiments are performed using round-robin scheduling with nanosecond time-scale switching times. PMID:24515003

Stabile, Ripalta; Rohit, Abhinav; Williams, Kevin A

2014-01-13

23

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

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

24

Fiber-handling robot and optical connection mechanisms for automatic cross-connection of multiple optical connectors  

NASA Astrophysics Data System (ADS)

Conventionally, in intelligent buildings in a metropolitan area network and in small-scale facilities in the optical access network, optical connectors are joined manually using an optical connection board and a patch panel. In this manual connection approach, mistakes occur due to discrepancies between the actual physical settings of the connections and their management because these processes are independent. Moreover, manual cross-connection is time-consuming and expensive because maintenance personnel must be dispatched to remote places to correct mistakes. We have developed a fiber-handling robot and optical connection mechanisms for automatic cross-connection of multiple optical connectors, which are the key elements of automatic optical fiber cross-connect equipment. We evaluate the performance of the equipment, such as its optical characteristics and environmental specifications. We also devise new optical connection mechanisms that enable the automated optical fiber cross-connect module to handle and connect angled physical contact (APC) optical connector plugs. We evaluate the performance of the equipment, such as its optical characteristics. The evaluation results confirm that the automated optical fiber cross-connect equipment can connect APC connectors with low loss and high return loss, indicating that the automated optical fiber cross-connect equipment is suitable for practical use in intelligent buildings and optical access networks.

Mizukami, Masato; Makihara, Mitsuhiro

2013-07-01

25

Insertion losses in micromachined free-space optical cross-connects due to fiber misalignments  

NASA Astrophysics Data System (ADS)

One of the most promising applications of MOEMS in Optical Networks is represented by free-space electro-mechanical Optical Cross-Connects (OXCs); these components show lower attenuation and lower insertion losses than concurrent components based on waveguides. Although some commercial micromachined electro-mechanical OXCs have been recently announced in the market, further deployment of these devices will certainly require decreasing insertion losses by proper design techniques of both, the electromechanical devices and the system packaging. In this document, we study insertion losses in micromachined free-space OXCs and the related packaging challenges; we assume in our discussions Single Mode Fiber (SMF) Cross-Connects using mirrors as beam steering devices. We start with an introduction to micromachined OXCs architectures, actuation mechanisms and collimators. In section 2, we present a study of insertion losses in SMFs links; the coupled effect of lateral and angular fiber misalignments is discussed. In section 3, we discuss insertion losses in OXCs when quarter-pitch GRIN lenses are used as fiber collimators; both sections 2 and 3 are based on Gaussian beam optics. In section 4, we explore the application of Scalar Diffraction Theory to OXC design, this is for calculating insertion losses including diffraction at the mirror plane. Finally, conclusions on insertion losses and the required fiber positioning accuracy are given.

Martinez, Sergio O.; Courtois, Bernard

2001-04-01

26

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 optical1 A Novel Architecture of an Optical Cross-connect Based on Tuneable Fibre Bragg Gratings - electroholographic matrix with ferro-electric crystals, and Fibre Bragg Grating (FBG) Based [1]. Crosstalk

Haddadi, Hamed

27

A compact, scalable cross-connect switch using total internal reflection due to thermally-generated bubbles  

Microsoft Academic Search

The authors present a novel, compact single mode fiber cross-connect switch which diverts light from one waveguide to a crossing waveguide in a silica planar lightwave circuit (PLC) using total internal reflection (TIR) off the interface between a waveguide and a thermally-generated bubble

J. E. Fouquet; S. Venkatesh; M. Troll; D. Chen; H. F. Wong; P. W. Barth

1998-01-01

28

Parallel and simultaneous spatial mode conversion using photorefractive crystal for photonic cross-connect  

NASA Astrophysics Data System (ADS)

In this paper, we present a novel technology for photonic cross-connect (PXC) in spatial mode domain for the realization of advanced and flexible optical transmission of spatial modes. The PXC is a kind of all -optical devices to switch highspeed optical signals for mode-division multiplexing (MDM) network and it is able to perform signal labeling in the spatial mode domain similar to current photonic switching in the wavelength domain. In addition, parallel and simultaneous mode conversion can be realized using multiplex holograms in a photorefractive crystal (PRC). In our experiment, during the recording process, a rewritable hologram is recorded in the PRC (LiNbO3) through the interference between the signal beam with certain input mode and the reference beam with the phase distribution of the desired output mode. Signal beams are generated by computer generated hologram (CGH) using a spatial light modulator (SLM) instead of an optical fiber emergent beam, and reference beams are generated by phase only modulation using another SLM. Subsequently, during the converting process, the input signal beam is converted into the desired output mode through the holographic diffract ion in the crystal and free-space propagation by an optical lens. By using phase code multiplexing method, parallel mode conversions can be realized. We performed an experiment on parallel mode conversions of several different conversion pairs. Signal beams and reference beams intersected in the PRC with an angle of 18.43 degree. The intensity distributions of converted modes were observed by CCD camera set on the Fourier plane. We confirmed that the two modes inter-conversion of LP11 with LP21 was successfully implemented.

Zhao, Yanfeng; Okamoto, Atsushi; Maeda, Tomohiro; Hirasaki, Yuki; Tomita, Akihisa; Bunsen, Masatoshi

2015-01-01

29

Tunable fibre Bragg grating based optical cross connects using multi-port optical circulators: structure and crosstalk analyses  

Microsoft Academic Search

SUMMARY Tunable fibre Bragg grating (FBG)-based reconfigureably non-blocking optical cross connect (OXC) using multi-port optical circulators (MOCs) are proposed and presented. In an FBG-MOC-based OXC, system insertion loss, system differential insertion loss together with OXC dimensions have been analysed and compared with FBG-OC-based OXC structure using three-port optical circulators (OCs). Optical crosstalk in a multiwavlength FBG-OC-based OXC is discussed, and

Xiangnong Wu; Zabih Ghassemlooy; Chao Lu

2002-01-01

30

Proof of feasibility of a free-space optical cross-connect system using digital MEMS  

NASA Astrophysics Data System (ADS)

This dissertation explores the feasibility of a new design for an optical cross-connection (OXC) device based on combining Micro-Electro-Mechanical Systems technology (MEMS) with an optical system called the White cell. The attractive feature of our design is that is a 3D design using a digital MEMS. This leads to a high number of ports and uses a simple control system for the MEMS. We demonstrate two different systems: a quartic configuration and a binary configuration. This is the first demonstration of either of these configurations as OXC systems. For the binary configuration we design and simulate three different spot displacement device (SDD) designs of our own creation: Tilted spherical mirror SDD, roof prism SDD and lens train SDD. We evaluate each design in terms of aberrations where the SDDs are configured to provide displacements of 500 mum and 2000 mum. From this evaluation we conclude that the roof prism SDD has the best performance of the three with a maximum astigmatism of 0.0013 mm. We simulate an 1 x 8 binary OXC system using the roof prism SDD. An underpopulated quartic cell is simulated and experimentally analyzed. The main objective of these experiments is to prove that is possible to switch any input to any particular output by controlling the titling mirrors of a MEMS. Due to the lack of a MEMS, we designed and made a "pseudo-MEMS," a structure whose main function is to imitate the characteristics of a proper MEMS, except that it cannot be reconfigured in real time. We are able to control the output row by sending the beam to specific spherical mirrors as predicted. Because the optical elements are uncoated we found an experimental loss of 27.54 dB per output. If we assume coated optical components the theoretical loss is only 2.46 dB for seven bounces. Another contribution of our work is to address the problem of beam coupling at the output plane for any White cell-based OXC. Our solution is based on curved a diffraction grating that takes advantage of a free-space architecture that makes it compatible with our OXC designs.

Argueta Diaz, Victor

31

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 ...

32

Proposal and demonstration of lambda-based internet exchange (IX) point using GMPLS protocols and photonic cross-connect (PXC)  

NASA Astrophysics Data System (ADS)

This paper proposes an architecture of a next-generation Internet eXchange (IX) based on the Generalized Multi-Protocol Label Switching (GMPLS) technologies and the photonic cross-connect (PXC), hereafter referred to a Lambda-IX. At first, we investigate a basic Lambda-IX model where the PXC provides a GMPLS-controlled lambda label-switched path (LSP) to interconnect different ISPs' border routers. We verify that the proposed Lambda-IX model can achieve the lambda-based and resilient interconnection for the ISPs, thanks to the PXC's bit-rate insensitive operation as well as fast restoration operation. In addition, once GMPLS functionalities are introduced on the border routers as well as the PXC, very flexible interconnection can be achieved such as demand-based creation and deletion of lambda LSPs. Next, we initiatively demonstrate an experimental Lambda-IX using a PXC and IP/MPLS routers. A Lambda-LSP with OC-192 bandwidth can be successfully created by using the GMPLS RSVP-TE signaling protocol via a control plane, and an EGP session of Border Gateway Protocol 4 (BGP-4) can be established over the Lambda-LSP created between the GMPLS-enabled border routers via a data plane. We also evaluate the fault recovery operation in the case where such Lambda-IXs are consisted of several PXCs and demonstrate that the Lambda-LSP as well as the corresponding BGP session can be restored with a fast recovery time of less than 1s. Through these investigation and demonstration, it is revealed that the Lambda-IX can be put to practical use aiming at inter-exchanging a large traffic in a near future, while enriching the functions of IX.

Tsuritani, Takehiro; Okamoto, Shuichi; Ogino, Nagao; Otani, Tomohiro; Tanaka, Hideaki

2004-10-01

33

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

34

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

35

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

DOEpatents

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

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

1994-01-01

36

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

DOEpatents

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

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

1994-01-04

37

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

38

Modular MEMS design and fabrication for an 80 x 80 transparent optical cross-connect switch  

NASA Astrophysics Data System (ADS)

The ability to transparently switch optical signals from one fiber to another without conversion to the electrical domain is a basic functionality that has a wide range of applications within the fiber optic industry. The so-called 3D-MEMS architecture has emerged as the preferred approach for building transparent, scalable systems with port-counts ranging from 16x16 to 1024x1024. The primary components of the 3D-MEMS architecture are fiber array, lens array, and MEMS mirror array. While a central theme in the MEMS industry is integration, we adopted a strategy of modularization. The key MEMS components, which include mirror array, ceramic substrate, and high-voltage drivers, were manufactured separately and then combined to yield a working product. Central to our modular approach was critical design parameter tolerancing to ensure manufacturability. Results from a large sampling of MEMS components and MEMS assemblies are presented to highlight manufacturability and performance.

Fernandez, Andres; Staker, Bryan P.; Owens, Windsor E.; Muray, Lawrence P.; Spallas, James P.; Banyai, William C.

2004-10-01

39

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

40

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

41

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

42

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...

43

CROSS CONNECTIONS SChOOl Of INfORmaTION STudIES (iSChOOl)  

E-print Network

SchoolofInformationStudies(iSchool)recognizes the pervasiveness of information technologies in all areas of society--from business and communication investigate the ways individuals interact with information and communication technologies and find innovative to understanding the impact of information, technology, and media literacies on children and adults · Center

McConnell, Terry

44

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

ERIC Educational Resources Information Center

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

Robertson, Bill

2014-01-01

45

Effect of flapping trajectories on the dragonfly aerodynamics  

Microsoft Academic Search

The effects of translational, figure-eight and double-figure-eight flapping trajectories on the dragonfly aerodynamics were\\u000a numerically studied by solving the Navier-Stokes equations. There is a common characteristic regarding the lift\\/drag force\\u000a coefficients that the downstroke flapping provides the lift forces while the upstroke flapping creates the thrust forces for\\u000a different flapping trajectories. The maximum lift force coefficient exceeds five for the

Jinliang Xu; Chuangxin Zhao; Yongli Zhang; Yang Zhang

2006-01-01

46

TRIMETHYLTIN-INDUCED HYPERACTIVITY: TIME COURSE AND PATTERN  

EPA Science Inventory

Adult male Long-Evans rats were intubated with either 0,5,6, or 7 mg/kg trimethyltin chloride. Activity was measured for 1 hr in a figure-eight maze 2 hr after dosing (day 0) and again on days 4,8,16 and 32 after dosing. On days 49-51, activity was measured in a figure-eight maze...

47

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

48

Wellness Programs: Preventive Medicine to Reduce Health Care Costs.  

ERIC Educational Resources Information Center

A wellness program is a formalized approach to preventive health care that can positively affect employee lifestyle and reduce future health-care costs. Describes programs for health education, smoking cessation, early detection, employee assistance, and fitness, citing industry success figures. (eight references) (MLF)

Martini, Gilbert R., Jr.

1991-01-01

49

Twisted structure of a cyclic hexapeptide containing a combination of alternating L-Leu-D-Leu-Aib segments.  

PubMed

We designed and synthesized a C(2)-symmetric cyclic hexapeptide, cyclo(L-Leu-D-Leu-Aib)(2) (2), which contains L- and D-amino acids and achiral Aib residues. The conformation of 2 was analyzed in the crystalline state and in solution, which was a unique figure-eight-shaped conformation. PMID:23006337

Demizu, Yosuke; Nagoya, Saori; Doi, Mitsunobu; Sato, Yukiko; Tanaka, Masakazu; Kurihara, Masaaki

2012-10-19

50

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...

51

Three-dimensional drawings in isometric conditions: planar segmentation of force trajectory  

Microsoft Academic Search

Normal human subjects grasped an isometric handle with an unrestrained, pronated hand. They were asked to exert forces continuously to draw lemniscates (figure eights) in specified or self-chosen planes and in the presence or absence of a three-dimensional visual feedback cursor and a visual template. In every condition, the mean plane orientation in the force space differed appreciably between the

Giuseppe Pellizzer; Joe T. Massey; Joseph T. Lurito; Apostolos P. Georgopoulos

1992-01-01

52

Mechanical Assessment of Veterinary Orthopedic Implant Technologies: Comparative Studies of Canine Fracture Fixation and Equine Arthrodesis Devices and Techniques  

E-print Network

Plate (LCP) was compared to a 14-16 hole broad Dynamic Compression Plate (DCP). Both constructs used a two “figure-eight” 1.25mm stainless steel wire tension band. Fatigue tests and to failure tests were conducted. There were no significant differences...

Baker, Sean Travis

2013-04-30

53

Simple scenarios of onset of chaos in three-dimensional maps  

E-print Network

We give a qualitative description of two main routes to chaos in three-dimensional maps. We discuss Shilnikov scenario of transition to spiral chaos and a scenario of transition to discrete Lorenz-like and figure-eight strange attractors. The theory is illustrated by numerical analysis of three-dimensional Henon-like maps and Poincare maps in models of nonholonomic mechanics.

Alexander Gonchenko; Sergey Gonchenko; Alexey Kazakov; Dmitry Turaev

2014-11-30

54

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

55

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

Microsoft Academic Search

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

Steven F. Kreft; Nancy M. Epling

2007-01-01

56

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

57

Development of a high-Performance MALDI-TOF mass spectrometer utilizing a spiral ion trajectory  

Microsoft Academic Search

A novel MALDI-TOF mass spectrometer that utilizes a spiral ion trajectory was developed. In this mass spectrometer, the ions\\u000a sequentially passed through four toroidal electrostatic sectors and revolved along a figure-eight-shaped orbit on a particular\\u000a projection plane. Each toroidal electrostatic sector had eight stories, and during multiple revolutions, the ion trajectory\\u000a shifted perpendicular to the projection plane in every cycle,

Takaya Satoh; Takafumi Sato; Jun Tamura

2007-01-01

58

The design and characteristic features of a new time-of-flight mass spectrometer with a spiral ion trajectory  

Microsoft Academic Search

A new time-of-flight (TOF) mass spectrometer with a corkscrew ion trajectory was designed and constructed. The spiral trajectory\\u000a was realized by using four toroidal electrostatic sectors. Each had fifteen-stories made of sixteen Matsuda plates piled up\\u000a inside a cylindrical electrostatic sector. The ions passed the four toroidal electrostatic sectors sequentially and revolved\\u000a along a figure-eight-shaped orbit on a certain projection

Takaya Satoh; Hisayuki Tsuno; Mitsuyasu Iwanaga; Yoshihiro Kammei

2005-01-01

59

Additive-pulse modelocking in fiber lasers  

Microsoft Academic Search

A self-starting additive-pulse modelocked (APM) all-fiber ring cavity laser operating in the negative group velocity regime is analyzed. The advantages of using a ring cavity with an isolator are discussed. The “figure eight” and the Sagnac loop reflector fiber laser are investigated in a novel way, and one form of their operation is related to the master equation of APM.

H. A. Haus; E. P. Ippen; K. Tamura

1994-01-01

60

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

Code of Federal Regulations, 2012 CFR

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

2012-10-01

61

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

Code of Federal Regulations, 2011 CFR

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

2011-10-01

62

SRLG Failure Localization in Optical Networks Satyajeet S. Ahuja, Srinivasan Ramasubramanian, and Marwan Krunz  

E-print Network

, intrusion, and human error. To ensure robust network operation, it is highly desired that these faults failures. Some failures, such as optical cross-connect port blocking and intrusion, can affect a single

Ramasubramanian, Srinivasan

63

SRLG Failure Localization in All-Optical Networks Using Monitoring Cycles and Paths  

E-print Network

, excessive bit errors, intrusion, and human error. It is desired that these faults be uniquely identified failures, such as optical cross-connect port blocking and intrusion, can affect a single or a specific

Ramasubramanian, Srinivasan

64

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

Code of Federal Regulations, 2010 CFR

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

2010-10-01

65

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

Code of Federal Regulations, 2014 CFR

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

2014-10-01

66

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

67

Topology switching in [32]heptaphyrins controlled by solvent, protonation, and meso substituents.  

PubMed

The switching of topology between "figure-eight", Möbius, and untwisted conformations in [32]heptaphyrins(1.1.1.1.1.1.1) has been investigated by using density functional theory calculations. Such a change is achieved by variation of one internal dihedral angle and, if properly controlled, can provide access to molecular switches with unique optical and magnetic properties. In this work, we have explored different conformational control methods, such as solvent, protonation and meso substituents. Despite its antiaromatic character, most of the [32]heptaphyrins (R=H, CH(3), CF(3), Ph, C(6)F(5)) adopt a figure-eight conformation in the neutral state, owing to their more-effective hydrogen-bonding interactions. The aromatic Möbius topology is only preferred with dichlorophenyl groups, which minimize the steric hindrance that arises from the bulky chlorine atoms. The conformational equilibrium is sensitive to the solvent, so polar solvents, such as DMSO, further stabilize the Möbius conformation. Protonation induces a conformational change into the Möbius topology, irrespective of the meso-aryl groups. In the triprotonated species, the conformational switch is blocked and a non-twisted conformer becomes much more stable than the figure-eight conformation. We have shown that the relative energies of the protonated [32]heptaphyrins are dominated by aromaticity. Importantly, this topology switching induces a dramatic change in the magnetic properties and reactivity of the macrocycles, as revealed by several energetic, magnetic, structural, and reactivity indices of aromaticity. PMID:23255381

Alonso, Mercedes; Geerlings, Paul; De Proft, Frank

2013-01-28

68

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

PubMed Central

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

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

2015-01-01

69

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

70

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

71

Comparison of major parameters in electrodynamic and electromagnetic levitation transport systems. Final report, July 1991-September 1992  

SciTech Connect

The study compiles quantitative design information that can be used in selecting a high-speed magnetic levitation system. Analytic models were developed for three configurations of electromagnetic (EMS) and three electrodynamic (EDS) systems, and for linear induction and synchronous motors. The models permit comparisons based on consistent assumptions. The following results indicate that the hoped-for advantages of EDS are difficult to realize: (1) all of the systems studied require smooth guideways to achieve acceptable ride quality unless active control techniques are developed; (2) the estimated weight of the superconducting magnets for the EDS systems is surprisingly large and comparable to the weight of the EMS onboard electromagnets; and (3) real power consumption in sheet guideway null flux EDS is similar to EMS when practical configurations and end effects are considered.

Brown, W.S.; Dauwalter, C.R.; Heger, F.; Weinberg, M.S.

1992-09-01

72

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

73

Knot state asymptotics II, Witten conjecture and irreducible representations  

E-print Network

This article pursues the study of the knot state asymptotics in the large level limit initiated in "Knot sate Asymptotics I". As a main result, we prove the Witten asymptotic expansion conjecture for the Dehn fillings of the figure eight knot. The state of a knot is defined in the realm of Chern-Simons topological quantum field theory as a holomorphic section on the SU(2)-character manifold of the peripheral torus. In the previous paper, we conjectured that the knot state concentrates on the character variety of the knot with a given asymptotic behavior on the neighborhood of the abelian representations. In the present paper we study the neighborhood of irreducible representations. We conjecture that the knot state is Lagrangian with a phase and a symbol given respectively by the Chern-Simons and Reidemeister torsion invariants. We show that under some mild assumptions, these conjectures imply the Witten conjecture on the asymptotic expansion of WRT invariants of the Dehn fillings of the knot. Using microlocal techniques, we show that the figure eight knot state satisfies our conjecture starting from q-differential relations verified by the colored Jones polynomials. The proof relies on a differential equation satisfied by the Reidemeister torsion along the branches of the character variety, a phenomenon which has not been observed previously as far as we know.

Laurent Charles; Julien Marche

2011-07-08

74

Magnetically evoked EMGs in rats.  

PubMed

Magnetic stimulation of the brain and spinal cord was carried out in rats to record electromyogram (EMGs) from the gastrocnemius. A figure-eight coil was set over the middle of the dorsum, and shifted from the cervical vertebrae to the sacrum. The motor evoked potentials (MEPs) with 4.8 msec latency by transcranial magnetic stimulation and the descending wave with 4.7 msec latency by C3-C4 stimulation were recorded. In evoked EMGs by magnetic stimulation over T9-T10, L4-L5, S2-S3 and Ca2-Ca3 spinal cord levels, the causes of these two evoked components with short (1.5 msec) and long (4.1 msec) latencies were estimated to be the eddy current generated from the rostral to the caudal portion of the spinal cord. With the increase in magnetic stimuli, the relative sizes and disappearance of H- and M-like responses were comparable with the ordinary M- and H-responses in electrically evoked EMGs. The magnetic stimulation of the spinal cord activated the sciatic nerve at their vertebral exit, because the latencies of the H- and M-responses were constant despite the changing stimulus sites. Although magnetic stimulation with the figure-eight coil can be focused on the target, it is necessary to take into consideration the influence of the eddy current flowing in the body. PMID:12564132

Chiba, Atsushi; Oshio, Ken-ichi; Inase, Masahiko

2003-01-01

75

OSNR game optimization with link capacity constraints in general topology WDM networks$  

E-print Network

OSNR game optimization with link capacity constraints in general topology WDM networks$ Yan Pan-to-noise ratio (OSNR). We first develop a model to describe the network and an OSNR model for each link switching nodes (e.g., optical cross-connects (OXCs)). An OSNR Nash game is formulated with coupled

Pavel, Lacra

76

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

77

JOURNAL DE PHYSIQUE CoZZoque C7, suppZ6ment au n07, Tome 40, JuiZZet 1979, nage C7-45 MONTE CARL0 SIMULATION OF ELECTRON AVALANCHE INHYDROGEN  

E-print Network

,, where qt is the total elastic collision cross section42 The determination of a set of collision cross connected m t h - ly on a curved line. The recent calculation of electronic excitation cross sections qe is assued by using the mmatum transfer elastic collision cross section q,. The gccd agrement of swarm

Boyer, Edmond

78

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

Microsoft Academic Search

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

James Drake

2010-01-01

79

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.

80

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

E-print Network

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

MacLennan, Bruce

81

EVOLUTION, JUNG, AND THEURGY Their Role in Modern Neoplatonism  

E-print Network

1 EVOLUTION, JUNG, AND THEURGY Their Role in Modern Neoplatonism Bruce MacLennan University This article explores the rich cross-connections between Neoplatonism, Jungian psychology, and evolutionary neuroethology can bring to Neoplatonism; in particular, I will use them to explicate theurgical practices. Since

MacLennan, Bruce

82

MICROBIAL GROWTH IN DISTRIBUTION SYSTEMS  

EPA Science Inventory

Drinking water is not sterile. Microbes are commonly found in delivered water. Some survive treatment, while others may be introduced due to cross connections, line breaks, or by other means. Biofilm forms in drinking water pipes when bacteria and other organisms adhere to pip...

83

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

E-print Network

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

Paris-Sud XI, Université de

84

Cleantech and an Analysis of the Platform Nature of Life Sciences: Further Reflections upon Platform Policies  

Microsoft Academic Search

Most articles about life sciences begin from healthcare. This article reaches healthcare by an unusual route. It begins by trying to map out the complex content of the “Cleantech” platform. It then cross-connects important parts of that to the Agro-food industry, only finally relating important aspects of that to Healthcare biosciences. By Cleantech is meant the complex of industry activities

Philip Cooke

2008-01-01

85

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.

86

Waveband MUX\\/DEMUX Using Concatenated Arrayed-Waveguide Gratings  

Microsoft Academic Search

We propose a new waveband MUX\\/DEMUX that uses two concatenated cyclic AWGs. The device can accommodate multiple input fibers simultaneously and as a result, the device cost and size of a waveband cross-connect can be significantly reduced.

Shoji Kakehashi; Hiroshi Hasegawa; Ken-ichi Sato; Osamu Moriwaki

2006-01-01

87

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

E-print Network

of host Ethernet NICs. While as with ordinary circuit switches, cross-connections have to be provisioned the access links from hosts to these switches are Gb/s Ethernet. In this work, an in-depth experimental durations (on the order of minutes to hours). Host-to-host (cluster-to-cluster) circuits are used for large

Veeraraghavan, Malathi

88

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...

89

High capacity digital network management and control  

Microsoft Academic Search

Modern wideband and broadband digital cross-connect systems are being increasingly deployed in fiber networks in the Bell Operating Companies (BOCs). A network controller maximizes the effectiveness of these elements in automating the management and control high capacity digital networks, and the provisioning and service restoration of DS1 and DS3 facilities. Strategies used in providing the above capabilities in a recently

D. K. Doherty; W. D. Hutcheson; K. K. Raychaudhuri

1990-01-01

90

Degenerate ground state and quantum tunneling in rotating condensates  

E-print Network

Quantum tunneling introduces a fundamental difference between classical and quantum mechanics. Whenever the classical ground state is non-unique (degenerate), quantum mechanics restore uniqueness thanks to tunneling. A condensate in a rotating trap with a vortex can have such a degenerate classical ground state, a degeneracy that is excluded in the absence of rotation at least when the Gross-Pitaevskii equation applies. If the rotating trap has a center of symmetry, like a figure eight (a peanut), the vortex may be on either side with the same energy yielding a degenerate ground state, a degeneracy lifted by quantum tunneling. We explain how to compute the rate of tunneling in the WKB limit by estimating the action of the trajectory in the Euclidean version of the dynamics.

Qiang Du; Martine Le Berre; Yves Pomeau

2012-09-07

91

Experimental studies of spheromak formation  

SciTech Connect

Studies in the PS-1 spheromak configuration can be effectively formed by a combined z- and theta-pinch technique on both a fast (tau/sub formation/approx. =tau/sub Alfve/n) and a much slower timescale. The gross tilt and shift instability of the toroid can be suppressed by a combination of conduction walls, shaping the separatrix by externally applied fields, and the use of ''figure-eight'' coils. Optimum stabilty is obtained for almost spherical toroids. Maximum field-reversal times for stable, well-confined toroids are > or =40 /..mu..sec, consistent with resistive decay. Temperatures during the stable decay are 5--10 eV; impurity radiation is an important energy-loss mechanism.

Bruhns, H.; Chin-Fatt, C.; Chong, Y.P.; DeSilva, A.W.; Goldenbaum, G.C.; Griem, H.R.; Hart, G.W.; Hess, R.A.; Irby, J.H.; Shaw, R.S.

1983-06-01

92

Reversible redox reaction between antiaromatic and aromatic states of 32?-expanded isophlorins.  

PubMed

32?-Antiaromatic expanded isophlorins with a varying number of thiophene and furan rings adopt either planar, ring-inverted, or twisted conformations depending on the number of furan rings in the macrocycle. However, they exhibit identical reactivity with respect to their oxidation to aromatic 30?-dicationic species under acidic conditions. These 32?-antiaromatic macrocycles can also be oxidized with [Et3O(+)SbCl6(-)] and NOBF4 to generate dications, thus confirming ring oxidation of macrocycles. Furthermore, they can be reduced back to their parent 32?-antiaromatic state by triethylamine, Zn, or FeCl2. Single-crystal X-ray diffraction analysis confirmed a figure-eight conformation for a hexafuran system, which opens to a planar structure upon oxidation. PMID:24828097

Gopalakrishna, Tullimilli Y; Anand, Venkataramanarao G

2014-06-23

93

Spinal reflex evoked by a pair of opposing pulsed magnetic fields  

NASA Astrophysics Data System (ADS)

A noninvasive method of magnetic stimulation of the spinal roots was designed. The basic idea is to concentrate induced eddy currents in a target by a pair of opposing pulsed magnetic fields. A figure-eight coil was positioned outside the median of the back so that time varying magnetic fields pass through the body in opposite directions around the target. Magnetic stimulation of the spinal roots of human and a rabbit was carried out. It was found that each spine level can be stimulated selectively, producing electromyographic waves related to both the H-reflex and M-wave. The results indicate that the M-wave can be produced by currents flowing either in the rostral or caudal direction, whereas the H-reflex is only generated by currents flowing in the caudal direction. The H-reflex elicited by magnetic stimulation of nerves in the vicinity of the spine becomes a new tool in diagnosis of neuromuscular system diseases.

Ueno, S.; Hiwaki, O.

1991-04-01

94

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.

Anne Jefferson

95

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.

96

Thomson scattering from ultrashort and ultraintense laser pulses.  

PubMed

The Thomson scattering in an ultraintense ( approximately 10(18) W cm(-2)) and ultrashort (20 fs) laser field is calculated that demonstrates different characteristics from those of the low-intensity field case. The electron trajectory no longer conforms to a figure-eight pattern, and the spectra demonstrate complex shifting and broadening to suggest that Thomson scattering can be used for characterizing pulsed lasers. The initial phase at the electron entrance of the field can critically affect the Thomson scattering, but its effect is weighted by the intensity profile of the field. As a result, the fourfold symmetry of the radiation pattern breaks down when the electron enters the field closer to the pulse peak. The relationship between the Thomson scattering and Compton scattering in the high field is analyzed. PMID:15697801

Gao, Ju

2004-12-10

97

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

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

98

Complex investigations of structural and optical homogeneities of low-photorefractivity lithium niobate crystals by the conoscopy and photoinduced and Raman light scattering methods  

NASA Astrophysics Data System (ADS)

Using photoinduced light scattering, conoscopy, and Raman spectroscopy methods, we have studied stoichiometric lithium niobate crystals and congruent crystals that were doped with Mg(0.078, 0.89 mas %), Zn(0.03, 0.52, 0.62), Cu(0.015), B(0.12), Gd(0.51), Y(0.46), Gd(0.23):Mg(0.75), Mg(0.86):Fe(0.0036), Ta(1.13):Mg(0.011), and Y(0.24):Mg(0.63) cations. It has been found that, depending on the kind of the pattern of photoinduced light scattering, investigated specimens can be divided into three groups. We have shown that the asymmetry of the indicatrix of photoinduced light scattering of LiNbO3 crystals is caused by birefringence of exciting laser radiation as it propagates perpendicularly to the polar axis of the crystal, whereas the asymmetry of the Raman spectrum arises due to the occurrence of spontaneous polarization, the vector of which is directed along the polar axis, and by birefringence. The pattern of the photoinduced light scattering depends on the difference of the refractive indices ? n = n o - n e of the ordinary ( n o ) and extraordinary ( n e ) rays and their energies E. If En o {ie259-1} En e , the proportion of the photoinduced light scattering has the shape of a three-layer round spot. For equal energies, the pattern has the shape of a symmetric figure-eight. At En o < En e , the figure-eight is asymmetric. In this case, its large "lobe" is directed in the positive direction of the polar axis of the crystal.

Sidorov, N. V.; Pikoul, O. Yu.; Kruk, A. A.; Teplyakova, N. A.; Yanichev, A. A.; Palatnikov, M. N.

2015-02-01

99

Example of high-bit-rate network based on soliton WDM system  

NASA Astrophysics Data System (ADS)

In this paper the authors present an example of optical transmission system based on soliton technology. Implementation of wavelength division multiplexing enables achievement of 40 Gbps in one channel. In described example a multipointmultipoint topology was applied and there the programmable WSXC optical cross connect was used. Model of such system was implemented in OptSim simulation software (ARTIS Software Corporation) 9. Finally an error-free soliton transmission was obtained on haul from 1300 to 1800 km.

Bara?ski, W?adys?aw; Gajda, Jerzy

2007-02-01

100

Comparison of Raw and Internet protocols in a HIPPI\\/ATM\\/SONET based gigabit network  

Microsoft Academic Search

We compare implementation of Raw and Internet protocols (TCP, UDP) on a programmable HIPPI host-interface called the Network Interface Unit. The network interface unit connects Pixel-Planes 5, a message-based graphics multicomputer, to a wide area gigabit network called VISTAnet. The BISDN network consists of a SONET cross-connect switch and an ATM switch. We discuss the tradeoffs between protocols for our

Raj K. Singh; Stephen G. Tell; Shaun J. Bharrat

1996-01-01

101

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

102

Fully reconfigurable optical add\\/drop multiplexing subsystem on a chip  

Microsoft Academic Search

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

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

2004-01-01

103

A simulation-based evaluation of two proposed alternatives to Luer devices for use in neuraxial anaesthesia.  

PubMed

The National Patient Safety Agency has issued a Patient Safety Alert with the aim of eliminating Luer connectors from equipment for lumbar puncture and subarachnoid injections by 1 April 2011, and from all neuraxial and regional anaesthesia equipment in 2013. B-link (UK) Ltd and InterVene Ltd have produced non-Luer connectors for neuraxial devices: the Neurax and Spinalok respectively. Using an adult spinal simulator, 59 experienced clinicians performed neuraxial procedures using these devices and reported on specific performance characteristics and overall usability. Cross-connectivity between non-Luer and Luer connectors was also examined. The median (IQR [range]) overall assessment scores (0-10 scale) of usability for the standard, Neurax and Spinalok systems were 8 (8-9 [7-10]), 6 (5-7 [0-8]) and 7 (6-8 [1-9]) for spinal procedures and 8 (8-9 [6-10]), 7 (5-8 [1-9]) and 4 (3-6 [0-9]) for epidural procedures, respectively. Both study systems scored significantly lower than standard equipment for overall performance of spinal and epidural procedures, although the performance of non-Luer devices was mostly rated 'adequate' or better. Both non-Luer connectors could cross-connect with one or more Luer connectors. Following feedback to the manufacturers, both systems have been modified and cross-connectivity apparently has been eliminated. Our results indicate that clinicians may not find non-Luer devices immediately 'user-friendly'. More importantly, some cross-connectivity with Luer devices was possible. Our findings illustrate that introducing equipment that is fully compliant with the National Patient Safety Agency alert poses a significant challenge to manufacturers and clinicians. We conclude that before introducing any non-Luer device into widespread use, independent, formal evaluation should be carried out. PMID:20946390

Cook, T M; Payne, S; Skryabina, E; Hurford, D; Clow, E; Georgiou, A

2010-11-01

104

Multiwavelength self-healing ring transparent networks  

Microsoft Academic Search

This paper describes the use of optical cross-connect nodes (as used in RACE project MWTN) for implementing multiwavelength unidirectional and bi-directional self-healing ring networks. A comparison of these two ring structures is presented in terms of the number of wavelength required to satisfy a uniform random traffic demand. Two protection strategies based on the electronic self-healing ring principles are applied

L. Wuttisittikulkij; M. J. O'Mahony

1995-01-01

105

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

Microsoft Academic Search

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

Wayne D. Grover; Demetrios Stamatelakis

1998-01-01

106

Self-healing rings in a synchronous environment  

Microsoft Academic Search

An overview of different self-healing network architectures, focusing on ring architectures, is presented. Digital cross-connect systems-based self-healing and diversely routed protection are briefly discussed. Since a typical self-healing network design may use all of the self-healing architectures, a discussion on applications perspectives, illustrating how the various self-healing technologies may best fit in the evolving network, is included

I. Haque; W. Kremer; K. Raychaudhuri

1991-01-01

107

Digital-data receiver synchronization method and apparatus  

DOEpatents

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

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

2009-09-08

108

Digital-data receiver synchronization  

DOEpatents

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

Smith, Stephen F.; Turner, Gary W.

2005-08-02

109

Digital-data receiver synchronization method and apparatus  

DOEpatents

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

Smith, Stephen F.; Turner, Gary W.

2005-12-06

110

Selective transparency in resilient optical networks  

Microsoft Academic Search

Core optical networks can benefit from lower costs and increased speed by reducing O-E-O conversions through use of ultra long reach optical transport, and bit-rate and wavelength transparent cross-connects. While pure optical transparency avoids the high cost of deploying optical termination units (OTUs) for each wavelength channel, it incurs nest, costs with additional fiber requirements and reduced provisioning capability. This

Randy Giles; Krishnan Kumaran; Debasis Mitra; Carl Nuzman; Iraj Saniee

2002-01-01

111

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

PubMed

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

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

2014-08-19

112

GYRO Simulations of Turbulently Driven Density Peaking in C-Mod Plasmas  

NASA Astrophysics Data System (ADS)

In turbulence simulations with H & D mixtures the deuterium density profile is slightly more peaked than hydrogen, while electron density peaking is insensitive to H/D. Adding a low-Z impurity has no effect on density peaking. Density peaking is weakly affected when the Ti profile is varied to align the predicted heat flux to the experimental transport analysis. Robust predictions of peaking are obtained with a novel simulation procedure: each hydrogenic species is represented by two ions in the simulations (e.g. two D and two H); they differ only by having different density gradients, but these offset each other so the total R/Lni for each species matches the electron R/Lne. Linear interpolation of the predicted particle fluxes determines the individual R/Lni that meet the null-flux condition required for each hydrogenic species; integrating the R/Lni profiles gives the predicted density peaking. Studies of the density peaking of low-, medium-, and high-Z impurities are planned.

Mikkelsen, D. R.; Bitter, M.; Delgado-Aparicio, L.; Hill, K. W.; Greenwald, M.; Hughes, J. W.; Ma, Y.; Podpaly, Y.; Rice, J. E.; Candy, J.; Waltz, R. E.

2011-11-01

113

A preliminary harmonic spline model from Magsat data  

NASA Technical Reports Server (NTRS)

A preliminary main field model for 1980 derived from a carefully selected subset of Magsat vector measurements, using the method of harmonic splines, is presented. This model (PHS /80/) for preliminary harmonic splines is the smoothest model (in the sense that the rms radial field at the core surface is minimum) consistent with the measurements (with an rms misfit of 10 nT to account for crustal and external fields as well as noise in the measurement procedure). Therefore PHS (80) is more suitable for studies of the core than models derived with the traditional least squares approach (e.g., GSFC /9/80/). A comparison is conducted of the characteristics of the harmonic spline spectrum, topology of the core field and especially the null-flux curves (loci where the radial field is zero) and the flux through patches bounded by such curves. PHS (80) is less complex than GSFC (9/80) and is therefore more representative of that part of the core field that the data constrain.

Shure, L.; Parker, R. L.; Langel, R. A.

1985-01-01

114

Micromirrors: overview and application roadmap  

NASA Astrophysics Data System (ADS)

The Telecom sector has driven until 2000 the development of micro-mirrors with subsystems like optical cross-connects and add/drop multiplexers for all-optical networks. Following the collapse of the telecom equipment market, much attention has been given to emerging applications in consumer electronics, IT, industry, and biomedical. WTC will give an overview on existing and emerging markets of micro-mirrors outside telecom. The various micro-mirror techniques and their respective applications from high value niches to mass markets will be presented. The supply chain will be analysed and a roadmap of implementation of micro-mirrors will be proposed.

Bouchaud, Jeremie; Bahle, Carsten; Wicht, Henning

2005-01-01

115

Spatial Light Modulators as Optical Crossbar Switches  

NASA Technical Reports Server (NTRS)

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

Juday, Richard

2003-01-01

116

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

117

Localization by indirect immunofluorescence of tetrin, actin, and centrin to the oral apparatus and buccal cavity of the macrostomal form of Tetrahymena vorax.  

PubMed

We have taken advantage of the size of the macrostomal oral apparatus of Tetrahymena vorax to investigate the immunofluorescent localization of three cytoskeletal proteins--tetrin, actin, and centrin. Tetrin and actin antibodies co-localize to cross-connectives that anchor the membranelles. These antibodies also recognize the coarse filamentous reticulum, a filament associated with the undulating membrane. Actin-specific localization extends beyond the coarse filamentous reticulum-undulating membrane complex into a region called the specialized cytoplasm. A centrin antibody localizes to the fine filamentous reticulum which, along with microtubules of the oral ribs, circumscribes the cytostomal opening. Models of phagocytic contraction based on these data are presented. PMID:15134263

McLaughlin, Neil B; Buhse, Howard E

2004-01-01

118

Ni(II) metalations of [40]- and [42]nonaphyrins(1.1.1.1.1.1.1.1.1): the largest doubly twisted Hückel antiaromatic molecule.  

PubMed

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

Soya, Takanori; Naoda, Koji; Osuka, Atsuhiro

2015-01-01

119

Comparative light and electron microscopic analyses of tenuivirus major noncapsid protein (NCP) inclusion bodies in infected plants, and of the NCP in vitro.  

PubMed

Tenuivirus infections are associated with the formation of abundant inclusion bodies and with the accumulation of large quantities of a viral noncapsid protein (NCP) in infected plants. Examination of maize stripe virus and rice hoja blanca virus-infected plant tissues using light, immunofluorescent, and electron microscopy showed that the inclusion bodies induced by the two viruses were very similar. Light microscopy revealed that both induced arrays of ring-like, figure-eight-like, and amorphous inclusions, frequently with a substructure of needle-shaped crystals. Immunofluorescent staining showed that all types of inclusion bodies contained the viral NCP but not the viral N protein, associated to the viral RNA. Electron microscopy revealed abundant amorphous semi-electron-opaque inclusion bodies; these had a fibrillar appearance but also occurred as compact, more electron-dense structures. Filamentous electron-opaque inclusion bodies were also detected. Immunogold labeling of ultrathin sections confirmed that all inclusion bodies included NCP and that none included viral N protein. Examination of purified NCP showed that it can form similar amorphous and crystalline arrays in vitro to the inclusion bodies observed in vivo. We propose that the common presence of NCP in all inclusion bodies implies the existence of a single type of intracellular inclusion body, the different developmental stages of which have previously been considered to be distinct inclusion bodies. PMID:8317091

Espinoza, A M; Pereira, R; Macaya-Lizano, A V; Hernández, M; Goulden, M; Rivera, C

1993-07-01

120

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

PubMed

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

Bourguet, Rémi; Triantafyllou, Michael S

2015-01-28

121

Knot state asymptotics I, AJ Conjecture and abelian representations  

E-print Network

Consider the Chern-Simons topological quantum field theory with gauge group SU(2) and level k. Given a knot in the 3-sphere, this theory associates to the knot exterior an element in a vector space. We call this vector the knot state and study its asymptotic properties when the level is large. The latter vector space being isomorphic to the geometric quantization of the SU(2)-character variety of the peripheral torus, the knot state may be viewed as a section defined over this character variety. We first conjecture that the knot state concentrates in the large level limit to the character variety of the knot. This statement may be viewed as a real and smooth version of the AJ conjecture. Our second conjecture says that the knot state in the neighborhood of abelian representations is a Lagrangian state. Using microlocal techniques, we prove these conjectures for the figure eight and torus knots. The proof is based on q-difference relations for the colored Jones polynomial. We also provide a new proof for the asymptotics of the Witten-Reshetikhin-Turaev invariant of the lens spaces and a derivation of the Melvin-Morton-Rozansky theorem from the two conjectures.

Laurent Charles; Julien Marche

2011-07-08

122

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

123

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

PubMed

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

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

2014-01-01

124

Neural network training by integration of adjoint systems of equations forward in time  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

125

Compensation Techniques in Accelerator Physics  

SciTech Connect

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

Hisham Kamal Sayed

2011-05-31

126

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

127

Theoretical study on the conformation and aromaticity of regular and singly N-confused [28]hexaphyrins.  

PubMed

Structures and electronic states of regular and singly N-confused [28]hexaphyrins(1.1.1.1.1.1) were thoroughly studied with the aid of DFT calculations. To obtain systematic information, all the conceivable structures (450 structures in total) were examined. Unlike the [26]hexaphyrins(1.1.1.1.1.1) reported previously (J. Org. Chem. 2010, 75, 8213-8223), the electronic states of [28]hexaphyrins were highly affected by their conformations. The planar conformers (dumbbell, rectangular, triangular) show Hückel antiaromaticity, while the singly twisted conformers show Möbius aromaticity. Figure-eight structures correspond to the doubly twisted structures and show nonaromaticity. Disruption of annulenic circuits in singly N-confused [28]hexaphyrins caused weakening of both aromatic and antiaromatic characteristics. Relative stabilities among conformers were mainly governed by the intramolecular hydrogen bonds and secondarily affected by the steric factors. In addition, interconversion pathways among conformers were proposed on the basis of calculations on singly N-confused [28]hexaphyrins. PMID:23971892

Toganoh, Motoki; Furuta, Hiroyuki

2013-09-20

128

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

129

The geostationary environment measurement spectrometer (GEMS) mission in view of ozone detection: Possibility analysis and comparison with the geosynchronous orbit  

NASA Astrophysics Data System (ADS)

The United States, Europe, Japan, and Korea are planned to launch a geostationary satellite carrying the UV-VIS spectrometer in 2017-2018. This study is concerned with research program to develop ozone retrieval algorithm in Korean geostationary mission (GEMS, 120E). We compare the daily frequency of clear-sky scene from the collocated OMI and MTSAT reflectance products, which demonstrate that the sub-hourly observation could assure 50.2 ± 11.5% better spatial continuity than daily observation. The geostationary orbit has extreme satellite zenith angle at high latitudes and far west-east area, and large solar zenith angles around sunrise or sunset. This extreme data will make it difficult to retrieve ozone with good accuracy. Chance suggested geosynchronous orbit in form of “figure-eight”. In contrast to geostationary satellite, geosynchronous satellites could move to where we are interesting due to their non-zero inclination. We compare the sensitivity of the current ozone retrieval algorithm to geostationary orbit with that of geosynchronous orbit, which is emphasized on first attempt. This result indicates that for low and sub-mid latitude areas there are insignificant improvement less 10% between geosynchronous and geostationary orbit platforms and whereas become important over high latitude.

Park, S. J.; Kim, J. H.

2010-12-01

130

Links with small lattice stick numbers  

NASA Astrophysics Data System (ADS)

Knots and links have been considered to be useful models for structural analysis of molecular chains such as DNA and proteins. One quantity that we are interested in for molecular links is the minimum number of monomers necessary for realizing them. In this paper we consider every link in the cubic lattice. The lattice stick number sL(L) of a link L is defined to be the minimum number of sticks required to construct a polygonal representation of the link in the cubic lattice. Huh and Oh found all knots whose lattice stick numbers are at most 14. They proved that only the trefoil knot 31 and the figure-eight knot 41 have lattice stick numbers of 12 and 14, respectively. In this paper we find all links with more than one component whose lattice stick numbers are at most 14. Indeed we prove combinatorically that s_L(2^2_1)=8, s_L(2^2_1 \\sharp 2^2_1)=s_L(6^3_2)=s_L(6^3_3)=12, s_L(4^2_1)=13, s_L(5^2_1)=14 and any other non-split links have stick numbers of at least 15.

Hong, Kyungpyo; No, Sungjong; Oh, Seungsang

2014-04-01

131

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

132

The meandering instability of a viscous thread  

E-print Network

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

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

2007-01-01

133

The twist, writhe and overall shape of supercoiled DNA change during counterion-induced transition from a loosely to a tightly interwound superhelix. Possible implications for DNA structure in vivo.  

PubMed

A cryo-electron microscopy study of supercoiled DNA molecules freely suspended in cryo-vitrified buffer was combined with Monte Carlo simulations and gel electrophoretic analysis to investigate the role of intersegmental electrostatic repulsion in determining the shape of supercoiled DNA molecules. It is demonstrated here that a decrease of DNA-DNA repulsion by increasing concentrations of counterions causes a higher fraction of the linking number deficit to be partitioned into writhe. When counterions reach concentrations likely to be present under in vivo conditions, naturally supercoiled plasmids adopt a tightly interwound conformation. In these tightly supercoiled DNA molecules the opposing segments of interwound superhelix seem to directly contact each other. This form of supercoiling, where two DNA helices interact laterally, may represent an important functional state of DNA. In the particular case of supercoiled minicircles (178 bp) the delta Lk = -2 topoisomers undergo a sharp structural transition from almost planar circles in low salt buffers to strongly writhed "figure-eight" conformations in buffers containing neutralizing concentrations of counterions. Possible implications of this observed structural transition in DNA are discussed. PMID:8289322

Bednar, J; Furrer, P; Stasiak, A; Dubochet, J; Egelman, E H; Bates, A D

1994-01-21

134

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

PubMed

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

Gershwin, Lisa-Ann; Dawes, Peter

2008-08-01

135

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

136

Proximal clavicle physeal fracture with posterior displacement: diagnosis, treatment, and prevention.  

PubMed

Posterior sternoclavicular fracture displacement can present as a posterior sternoclavicular joint dislocation and is rare in the pediatric population. This article provides an algorithm for evaluation and management.A 14-year-old boy with a previously undiagnosed posterior sternoclavicular displacement presented with persistent 7/10 shoulder pain extending into his neck after undergoing nonoperative treatment for an unconfirmed diagnosis at another emergency department. Plain radiographs revealed a displacement of the right medial clavicle, and the position of the clavicular head indicated advanced imaging. Computed tomography showed the posterior portion of the clavicular head butting against the left braciocephalic vein at its confluence with the superior vena cava. The patient underwent open reduction and internal fixation. After exposing the sternoclavicular joint, a Salter-Harris I fracture with no evidence of vascular injury was confirmed. The fracture was reduced and stabilized using figure-eight #5 Ethibond sutures (Ethicon, Somerville, New Jersey), and the patient was placed in an immobilizer for 1 week. At 1 year postoperatively, the patient regained full range of motion and was completely healed.Posterior clavicle displacements are potentially devastating injuries that are difficult to diagnose. Coordinating operative treatment with orthopedic and general surgery is indicated to manage the fracture or displacement and potential vascular injury. Due to difficulties in maintaining a closed reduction, open reduction and internal fixation is the preferred mode of treatment for the reduction of all posterior clavicular fracture displacements. PMID:22229601

Koch, Matthew J; Wells, Lawrence

2012-01-01

137

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

138

Rainfall, runoff, and suspended sediment delivery relationships in a small agricultural watershed of the Three Gorges area, China  

NASA Astrophysics Data System (ADS)

Following construction of the Three Gorges Dam, many farmers resettled in surrounding mountain areas and cultivated marginal lands, which are mostly on steep slopes with soil of poor structure. In general, high soil loss rates occur during intense storms. Therefore, soil erosion is a major environmental problem in the Three Gorges area (TGA) of China. Understanding and quantifying sediment load is important for sustainable agriculture and the environment in this region. This paper analyzes the relationships between rainfall, runoff, and sediment transport in the Wangjiaqiao watershed. Strong seasonal and monthly variability in sediment load was found. Sediment was strongly transported during summer months, a period when frequent flood events of high magnitude and intensity occurred. Analysis of the relationships between precipitation, discharge and sediment transport at an individual event scale showed significant correlations between total precipitation, peak discharge, total water yield, maximum 30 min rainfall intensity, and sediment-related variables. Stepwise multiple regression analysis revealed that rainfall amount is the major cause of runoff, while events producing a large discharge in a short time play an important role in inducing severe soil erosion. During 40 flood events, three different types of hysteretic loops were observed: clockwise (28 events, 70%), figure-eight (5 events, 12.5%), and complex (7 events, 17.5%). The results of this study confirm the complex and heterogeneous nature of sediment response in the Wangjiaqiao watershed.

Nu-Fang, Fang; Zhi-Hua, Shi; Lu, Li; Cheng, Jiang

2011-12-01

139

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

PubMed

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

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

2014-08-01

140

Three-body choreographies in given curves  

NASA Astrophysics Data System (ADS)

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

Ozaki, Hiroshi; Fukuda, Hiroshi; Fujiwara, Toshiaki

2009-10-01

141

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

142

Time-dependent effects of low-frequency repetitive transcranial magnetic stimulation of the supramarginal gyrus.  

PubMed

In this paper, we report our studies of the effects of stimulating the bilateral supramarginal gyrus (SMG) with low-frequency transcranial magnetic stimulation (rTMS) or short-term rTMS on brain excitability in humans. We analyzed the effects of various durations of stimulation on P300 latencies of the event-related potential (ERP). Magnetic pulses were delivered using a figure-eight flat coil. The intensity of rTMS was set to 80 % of the subject's motor threshold. In each round of rTMS, 100 magnetic pulses were applied over the scalp at frequencies of 1.00, 0.75, and 0.50 Hz. ERPs were measured prior to magnetic stimulation as a control. The effects of magnetic stimulation were then determined by measuring its effects on P300 latencies elicited by an odd-ball task. These latencies were measured before and 0, 5, 10, and 15 min after the magnetic stimulation. 1.00 Hz low-frequency rTMS of the left SMG decreased P300 latencies for approximately 10 min. In contrast, 0.50 Hz rTMS of the left SMG resulted in delayed P300 latencies for approximately 15 min. We furthermore found that 0.75 Hz rTMS of the left SMG and 1.00, 0.75 and 0.5 Hz rTMS of the right SMG did not affect P300 latencies. These results suggest that the duration of the effects of rTMS depend on the frequency of stimulation. PMID:23366649

Torii, T; Sato, A; Iwahashi, M; Itoh, Y; Iramina, K

2012-01-01

143

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

144

Dual-wavelength operation of continuous-wave and mode-locked erbium-doped fiber lasers  

NASA Astrophysics Data System (ADS)

We study numerically and experimentally multiple-wavelength operation of an erbium-doped figure-eight fiber laser including a multiple-bandpass optical filter formed by two concatenated fiber tapers. Both continuous-wave and pulsed operations are considered. In the continuous-wave regime, stable long-term operation at multiple closely spaced wavelengths is only obtained if fine adjustments of the cavity losses are performed. Under these conditions, simultaneous lasing at up to four wavelengths separated by 1.5 nm was observed experimentally. Tunable single-wavelength operation over more than 20 nm is also observed in the continuous-wave regime. In the passive mode locking regime, numerical simulations indicate that mechanisms involving the filter losses and the nonlinear transmission characteristic of the NOLM contribute in principle to stabilize dual-wavelength operation, allowing less demanding cavity loss adjustments. In this regime, the problem of synchronization between the pulse trains generated at each wavelength adds an additional dimension to the problem. In presence of cavity dispersion, the pulses at each wavelength tend to be asynchronous if the wavelength separation is large, however they can be synchronous in the case of closely spaced wavelengths, if cross-phase modulation is able to compensate for the dispersion-induced walkoff. Experimentally, fundamental and 2nd-order harmonic mode locking was observed, characterized by the generation of noise-like pulses. Finally, a regime of multi-wavelength passive Q-switching was also observed. We believe that this work will be helpful to guide the design of multiple-wavelength fiber laser sources, which are attractive for a wide range of applications including Wavelength Division Multiplexing transmissions, signal processing and sensing.

Pottiez, O.; Martinez-Rios, A.; Monzon-Hernandez, D.; Ibarra-Escamilla, B.; Kuzin, E. A.; Hernandez-Garcia, J. C.

2012-06-01

145

The genetic landscape of a cell.  

PubMed

A genome-scale genetic interaction map was constructed by examining 5.4 million gene-gene pairs for synthetic genetic interactions, generating quantitative genetic interaction profiles for approximately 75% of all genes in the budding yeast, Saccharomyces cerevisiae. A network based on genetic interaction profiles reveals a functional map of the cell in which genes of similar biological processes cluster together in coherent subsets, and highly correlated profiles delineate specific pathways to define gene function. The global network identifies functional cross-connections between all bioprocesses, mapping a cellular wiring diagram of pleiotropy. Genetic interaction degree correlated with a number of different gene attributes, which may be informative about genetic network hubs in other organisms. We also demonstrate that extensive and unbiased mapping of the genetic landscape provides a key for interpretation of chemical-genetic interactions and drug target identification. PMID:20093466

Costanzo, Michael; Baryshnikova, Anastasia; Bellay, Jeremy; Kim, Yungil; Spear, Eric D; Sevier, Carolyn S; Ding, Huiming; Koh, Judice L Y; Toufighi, Kiana; Mostafavi, Sara; Prinz, Jeany; St Onge, Robert P; VanderSluis, Benjamin; Makhnevych, Taras; Vizeacoumar, Franco J; Alizadeh, Solmaz; Bahr, Sondra; Brost, Renee L; Chen, Yiqun; Cokol, Murat; Deshpande, Raamesh; Li, Zhijian; Lin, Zhen-Yuan; Liang, Wendy; Marback, Michaela; Paw, Jadine; San Luis, Bryan-Joseph; Shuteriqi, Ermira; Tong, Amy Hin Yan; van Dyk, Nydia; Wallace, Iain M; Whitney, Joseph A; Weirauch, Matthew T; Zhong, Guoqing; Zhu, Hongwei; Houry, Walid A; Brudno, Michael; Ragibizadeh, Sasan; Papp, Balázs; Pál, Csaba; Roth, Frederick P; Giaever, Guri; Nislow, Corey; Troyanskaya, Olga G; Bussey, Howard; Bader, Gary D; Gingras, Anne-Claude; Morris, Quaid D; Kim, Philip M; Kaiser, Chris A; Myers, Chad L; Andrews, Brenda J; Boone, Charles

2010-01-22

146

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

147

MANS and ATM: evolution, interconnection, and interworking  

NASA Astrophysics Data System (ADS)

This paper, based on work within RACE project R1022 -- `Technology for ATD,' places the evolution of MANs towards ATM within the overall context of ATM introduction and evolution. Beginning with a major motivating factor, the need for LAN to LAN interconnection, a likely evolution of MANs is described, from first introduction, through interconnection via the ATM cross connect network, to the provision of connectionless data service over the ATM network. The introduction and evolution of ATM in general is then considered. This begins with a review of basic introductory approaches (substitution, island, overlay) and how they can be applied. An overview of the main customer groupings and their likely service requirements is provided as a precursor to discussing how fiber will be used in the access network for both business and residential customers. The paper concludes with an assessment of how MAN evolution towards ATM fits within the overall context of ATM introduction and the provision of broadband services.

Sara, Lini; Cuthbert, Laurie; Pitts, Jonathan

1993-10-01

148

Full vector spherical harmonic analysis of the Holocene geomagnetic field  

NASA Astrophysics Data System (ADS)

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

Richardson, Marcia

149

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

150

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

151

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

152

Surface nuclear magnetic resonance measurements of unfrozen sediments below thermokarst lakes  

NASA Astrophysics Data System (ADS)

Unfrozen sediments below thermokarst lakes have been identified as a key source of methane to the atmosphere with potential implications for climate change. Estimating the depth extent of thaw bulbs is a critical step towards determining the volume of unfrozen material potentially producing methane, however the depth is challenging to obtain using conventional borehole-based methods. It is also important to determine if thaw bulbs are hydraulically connected to deep, regional groundwater (open talik) or if they are bounded by permafrost on all sides (closed talik). Surface nuclear magnetic resonance (surface-NMR) is a geophysical method that shows promise for noninvasively estimating thaw bulb depth due to the direct sensitivity to unfrozen water content and appropriate depth of investigation of up to 100 m. Recent advances in the instrumentation have greatly improved the suitability of surface-NMR for making measurements, even in areas with moderate background electromagnetic noise. In this proof-of-concept study, we made surface-NMR measurements on thermokarst lakes near Fairbanks, Alaska. The study was conducted on ice when the lakes were frozen during the winter to enable easy deployment of the instrument over the deepest portions of the lakes. Figure-eight transmitting/receiving loop configurations were utilized along with separate noise loops to compensate for electromagnetic noise associated with the urbanized Fairbanks area. Surface-NMR soundings were inverted using a 1D blocky inversion that simultaneously fit the NMR amplitude and decay time data with layers defined as ice, lake water, thaw bulb sediments and frozen sediments. At one 6 m deep lake the thaw bulb extended beyond the maximum sensitive depth of the surface-NMR measurement (>23 m). At a smaller, 1.2 m deep lake, a thaw bulb depth of 4 m below the lake surface was observed underlain by permafrost. For comparison, we also made measurements at a terrestrial permafrost location with borehole control to provide ground truth. We have demonstrated that surface-NMR is highly suitable for thermokarst and permafrost studies when thawed permafrost contains significant volumes of unfrozen water.

Parsekian, A.; Grosse, G.; Walbrecker, J.; Muller-Petke, M.; Keating, K.; Liu, L.; Jones, B. M.; Knight, R. J.

2012-12-01

153

Enhanced detection of hydraulically active fractures by temperature profiling in lined heated bedrock boreholes  

NASA Astrophysics Data System (ADS)

SummaryThe effectiveness of borehole profiling using a temperature probe for identifying hydraulically active fractures in rock has improved due to the combination of two advances: improved temperature sensors, with resolution on the order of 0.001 °C, and temperature profiling within water inflated flexible impermeable liners used to temporarily seal boreholes from hydraulic cross-connection. The open-hole cross-connection effects dissipate after inflation, so that both the groundwater flow regime and the temperature distribution return to the ambient (background) condition. This paper introduces a third advancement: the use of an electrical heating cable that quickly increases the temperature of the entire static water column within the lined hole and thus places the entire borehole and its immediate vicinity into thermal disequilibrium with the broader rock mass. After heating for 4-6 h, profiling is conducted several times over a 24 h period as the temperature returns to background conditions. This procedure, referred to as the Active Line Source (ALS) method, offers two key improvements over prior methods. First, there is no depth limit for detection of fractures with flow. Second, both identification and qualitative comparison of evidence for ambient groundwater flow in fractures is improved throughout the entire test interval. The benefits of the ALS method are demonstrated by comparing results from two boreholes tested to depths of 90 and 120 m in a dolostone aquifer used for municipal water supply and in which most groundwater flow occurs in fractures. Temperature logging in the lined holes shows many fractures in the heterothermic zone both with and without heating, but only the ALS method shows many hydraulically active fractures in the deeper homothermic portion of the hole. The identification of discrete groundwater flow at many depths is supported by additional evidence concerning fracture occurrence, including continuous core visual inspection, acoustic televiewer logs, and tests for hydraulic conductivity using straddle packers as well as rock core VOC data, where available, that show deep penetration and many migration pathways. Confidence in the use of temperature profiles and the conceptual model is provided by numerical simulation and the demonstrated reproducibility of the evolution of the temperature signal measured in the lined holes with and without heating. This approach for using temperature profiling in lined holes with heating is a practical advance in fractured rock hydrogeology because the liners are readily available, the equipment needed for heating is low cost and rugged, and the time needed to obtain the profiles is not excessive for most projects.

Pehme, P. E.; Parker, B. L.; Cherry, J. A.; Molson, J. W.; Greenhouse, J. P.

2013-03-01

154

Compensation control study based on impairment-aware for Wavelength Switched Optical Networks (WSON)  

NASA Astrophysics Data System (ADS)

In an optical network, the optical signal transmitted along the lightpath may need to travel through a number of cross connect switches (OXCs), optical amplifiers, and fiber segments. While the signal propagates toward its destination, the optical components would continuously degrade the signal quality by inducing impairments. When the signal degradation is so severe that the received bit-error rate (BER) becomes unacceptably high, the lightpath would not be able to provide good service quality to a connection request. Such a lightpath, which has poor signal quality due to transmission impairments in the physical layer, should not be used for connection provisioning in the network layer. This paper presents an adaptive PID controller based on the power compensation of BP neural network to restrict the influence of the impairment power for a networked control system (NCS) with the presence of controller time-delay and power compensation at amplifiers' node firstly. Control algorithms continuously adjust their channel powers in response to dynamic information from the network links. And the controller could achieve the on-line adaptive power compensation without changing the parameters of PID controller. The results of simulation show that the proposed controller could adjust better channel power at the transmitter sites and achieve channel optical signal-to-noise ratio (OSNR) optimization with controller's time-delay.

Zhao, Dongyan; Zhang, Jie; Zhao, Yongli

2011-10-01

155

Real-time determination of the efficacy of residual disinfection to limit wastewater contamination in a water distribution system using filtration-based luminescence.  

PubMed

Water distribution systems can be vulnerable to microbial contamination through cross-connections, wastewater backflow, the intrusion of soiled water after a loss of pressure resulting from an electricity blackout, natural disaster, or intentional contamination of the system in a bioterrrorism event. The most urgent matter a water treatment utility would face in this situation is detecting the presence and extent of a contamination event in real-time, so that immediate action can be taken to mitigate the problem. The current approved microbiological detection methods are culture-based plate count methods, which require incubation time (1 to 7 days). This long period of time would not be useful for the protection of public health. This study was designed to simulate wastewater intrusion in a water distribution system. The objectives were 2-fold: (1) real-time detection of water contamination, and (2) investigation of the sustainability of drinking water systems to suppress the contamination with secondary disinfectant residuals (chlorine and chloramine). The events of drinking water contamination resulting from a wastewater addition were determined by filtration-based luminescence assay. The water contamination was detected by luminescence method within 5 minutes. The signal amplification attributed to wastewater contamination was clear-102-fold signal increase. After 1 hour, chlorinated water could inactivate 98.8% of the bacterial contaminant, while chloraminated water reduced 77.2%. PMID:20480769

Lee, Jiyoung; Deininger, Rolf A

2010-05-01

156

Death and Transfiguration in Static Staphylococcus epidermidis Cultures  

PubMed Central

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

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

2014-01-01

157

Microbial health risks associated with exposure to stormwater in a water plaza.  

PubMed

Climate change scenarios predict an increase of intense rainfall events in summer in Western Europe. Current urban drainage systems cannot cope with such intense precipitation events. Cities are constructing stormwater storage facilities to prevent pluvial flooding. Combining storage with other functions, such as recreation, may lead to exposure to contaminants. This study assessed the microbial quality of rainwater collected in a water plaza and the health risks associated with recreational exposure. The water plaza collects street run-off, diverges first flush to the sewer system and stores the rest of the run-off in the plaza as open water. Campylobacter, Cryptosporidium and Legionella pneumophila were the pathogens investigated. Microbial source tracking tools were used to determine the origin (human, animal) of the intestinal pathogens. Cryptosporidium was not found in any sample. Campylobacter was found in all samples, with higher concentrations in samples containing human Bacteroides than in samples with zoonotic contamination (15 vs 3.7 gc (genomic copies)/100 mL). In both cases, the estimated disease risk associated with Campylobacter and recreational exposure was higher than the Dutch national incidence. This indicates that the health risk associated with recreational exposure to the water plaza is significant. L. pneumophila was found only in two out of ten pond samples. Legionnaire's disease risks were lower than the Dutch national incidence. Presence of human Bacteroides indicates possible cross-connections with the CSS that should be identified and removed. PMID:25706222

Sales-Ortells, Helena; Medema, Gertjan

2015-05-01

158

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

159

Earth and Space Science in the new NRC "Conceptual Framework for New Science Education Standards"  

NASA Astrophysics Data System (ADS)

The National Academy of Sciences has begun the process of creating a new set of K-12 science education standards. At the start of 2011 the National Research Council will release its “Conceptual Framework for New Science Education Standards,” which provides a vision for creating new and improved set of guidelines for the teaching of science. The Earth & Space content was formulated by an Earth & Space Design Team, consisting of the authors of this abstract. The “Framework,” funded by the Carnegie Foundation of New York, places a greater emphasis on the practices of learning and on major cross-cutting themes that run through the four content areas: Earth and Space Science, Physical Science, Life Science, and Engineering and Technology. One aim of the framework is to inspire a set of science standards that are more fundamental, cross-connecting, and less fact-oriented. Compared to previous efforts, the Earth & Space Science component places greater emphasis on a systems approach to Earth Science, on the interrelationships between humans and Earth systems, and on the science surrounding and connected to climate change. The organization Achieve, Inc., has already begun to use this “Framework” for the creation of a set of national K-12 science education standards.

Wysession, M. E.; Duggan-Haas, D. A.; Linneman, S. R.; Pyle, E.; Schatz, D.

2010-12-01

160

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

161

Manufacturing microcomponents for optical information technology using the LIGA technique  

NASA Astrophysics Data System (ADS)

Recently, splices and connectors for fibers ribbons, optical cross connects and especially planar waveguide devices have been fabricated via LIGA in combination with precision engineering techniques. LIGA combines high precision and mass production capability, necessary for products designed for applications in the telecom and datacom market. In this presentation the fabrication of three-level molding and embossing tools is presented, which have been used for the manufacturing of waveguide prestructures consisting of waveguide channels and bier-to-waveguide coupling grooves. The precision of the tools is better than 1 micrometers in all directions, which allows for simple passive pigtailing. A first product, a precision of the tool is better than 1 micrometers in all directions, which allows for simple passive pigtailing. A first product, sixfold array of 4 X 4 multimode star couplers has been realized. The molding behavior of PMMA and COC material has been tested and compared. Production and assembly was tested by fabricating a series of 300 star couplers. The average insertion los has been found better than 9dB, the uniformity better than 3dB, both measured at 830nm. THe device is designed for application in optical backplanes for high-speed computers.

Bauer, Hans-Dieter; Ehrfeld, Wolfgang; Hossfeld, Jens; Paatzsch, Thomas

1999-09-01

162

Unfolded protein response in filamentous fungi-implications in biotechnology.  

PubMed

The unfolded protein response (UPR) represents a mechanism to preserve endoplasmic reticulum (ER) homeostasis that is conserved in eukaryotes. ER stress caused by the accumulation of potentially toxic un- or misfolded proteins in the ER triggers UPR activation and the induction of genes important for protein folding in the ER, ER expansion, and transport from and to the ER. Along with this adaptation, the overall capacity for protein secretion is markedly increased by the UPR. In filamentous fungi, various approaches to employ the UPR for improved production of homologous and heterologous proteins have been investigated. As the effects on protein production were strongly dependent on the expressed protein, generally applicable strategies have to be developed. A combination of transcriptomic approaches monitoring secretion stress and basic research on the UPR mechanism provided novel and important insight into the complex regulatory cross-connections between UPR signalling, cellular physiology, and developmental processes. It will be discussed how this increasing knowledge on the UPR might stimulate the development of novel strategies for using the UPR as a tool in biotechnology. PMID:25384707

Heimel, Kai

2015-01-01

163

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

NASA Astrophysics Data System (ADS)

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

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

2011-02-01

164

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

PubMed Central

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

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

2014-01-01

165

Telecommunications administration standard  

SciTech Connect

The administration of telecommunications is critical to proper maintenance and operation. The intent is to be able to properly support telecommunications for the distribution of all information within a building/campus. This standard will provide a uniform administration scheme that is independent of applications, and will establish guidelines for owners, installers, designers and contractors. This standard will accommodate existing building wiring, new building wiring and outside plant wiring. Existing buildings may not readily adapt to all applications of this standard, but the requirement for telecommunications administration is applicable to all buildings. Administration of the telecommunications infrastructure includes documentation (labels, records, drawings, reports, and work orders) of cables, termination hardware, patching and cross-connect facilities, telecommunications rooms, and other telecommunications spaces (conduits, grounding, and cable pathways are documented by Facilities Engineering). The investment in properly documenting telecommunications is a worthwhile effort. It is necessary to adhere to these standards to ensure quality and efficiency for the operation and maintenance of the telecommunications infrastructure for Sandia National Laboratories.

Gustwiller, K.D. [GTE Customer Networks, Albuquerque, NM (United States)

1996-05-01

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

Hydraulic testing using a versatile straddle packer system for improved transmissivity estimation in fractured-rock boreholes  

NASA Astrophysics Data System (ADS)

Equipment has been developed for straddle packer testing in fractured-rock boreholes to conduct four types of tests (constant-head step tests, slug tests, constant-rate pumping tests, and recovery tests) without deflating the packers or adjusting equipment in the hole between tests. The goal is to achieve improved accuracy and precision in the determination of transmissivity ( T). Water-pressure measurements are recorded using pressure transducers positioned above and below the test interval to identify connections from the test interval to the open borehole. Insights concerning the nature of test conditions are gathered with this equipment to assess errors related to deviations from assumptions inherent in the mathematical models used to determine T, including validation of the Darcian flow assumption, validation of slug test assumptions, cross-connection to the open borehole, inadequate borehole development, and dual permeability, thereby giving greater confidence in the calculated T values. When the errors indicated above are minimized, the constant-head step tests, slug tests and constant-rate pumping/recovery tests give nearly identical values. This multiple-test approach to fractured-rock studies increases confidence in test results, which is important when the goal is characterization of fracture networks for contaminant transport and fate assessment.

Quinn, Patryk; Cherry, John A.; Parker, Beth L.

2012-12-01

168

Assessment of domestic water quality: case study, Beirut, Lebanon.  

PubMed

In urban cities, the environmental services are the responsibility of the public sector, where piped water supply is the norm for urban household. Likewise, in Beirut City (capital of Lebanon) official water authorities are the main supplier of domestic water through a network of piping system that leaks in many areas. Beirut City and its suburbs are overpopulated since it is the residence of 1/3 of the Lebanese citizens. Thus, Beirut suffers deficiency in meeting its water demand. Water rationing, as a remedial action, is firmly established since four decades by the Lebanese Water Authorities. Consumers resorted then to private wells to supplement their domestic water needs. Consequently, household water quality is influenced by external factors relating to well water characteristics and internal factors depending on the types of the pipes of the distribution network and cross connections to sewer pipes. These factors could result in chemical and microbial contamination of drinking water. The objective of this study is to investigate domestic water quality variation in Beirut City emerging form the aforementioned factors. The presented work encircles a typical case study of Beirut City (Ras Beirut). Results showed deterioration pattern in domestic water quality. The predicted metal species and scales within the water pipes of distribution network depended on water pH, hardness, sulfate, chloride, and iron. The corrosion of iron pipes mainly depended on Mg hardness. PMID:17380419

Korfali, Samira Ibrahim; Jurdi, Mey

2007-12-01

169

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

170

Numerical and experimental study of a high port-density WDM optical packet switch architecture for data centers.  

PubMed

Data centers have to sustain the rapid growth of data traffic due to the increasing demand of bandwidth-hungry internet services. The current intra-data center fat tree topology causes communication bottlenecks in the server interaction process, power-hungry O-E-O conversions that limit the minimum latency and the power efficiency of these systems. In this paper we numerically and experimentally investigate an optical packet switch architecture with modular structure and highly distributed control that allow configuration times in the order of nanoseconds. Numerical results indicate that the candidate architecture scaled over 4000 ports, provides an overall throughput over 50 Tb/s and a packet loss rate below 10(-6) while assuring sub-microsecond latency. We present experimental results that demonstrate the feasibility of a 16x16 optical packet switch based on parallel 1x4 integrated optical cross-connect modules. Error-free operations can be achieved with 4 dB penalty while the overall energy consumption is of 66 pJ/b. Based on those results, we discuss feasibility to scale the architecture to a much larger port count. PMID:23388919

Di Lucente, S; Luo, J; Centelles, R Pueyo; Rohit, A; Zou, S; Williams, K A; Dorren, H J S; Calabretta, N

2013-01-14

171

Multi-granularity optical switching networks test-bed  

NASA Astrophysics Data System (ADS)

Multi-Granularity optical switching technology has only recently attracted attention from the optical networking industry for its practical importance in reducing port count, the associated control complexity, and the cost of optical cross-connects (OXC). In this paper, the advantage of MG-OXC comparing to the ordinary OXC is introduced and the Multi-Granularity Optical Switching test-bed based on ASON (Automatically Switching Optical Network) is presented. This test-bed is composed of three different plants, namely the transport plane, the control plane and the management plane. We have analyzed the architecture of MG-OXC and provided the scheme of multi-granularity optical switching node. In the end some experiments have been done. We firstly have done the experiment in the creation and release of optical path. The optical path could be a wavelength path or a waveband path. And the second experiment has been done to test the capacity of the traffic grooming in the multi-granularity optical networks. The last experiment is performed to test the protection and restoration under the conditions of the node failure, the wavelength failure and the waveband failure, etc. Finally the results are reported and they show that the test-bed can achieve the expected functions under the control of the control plane of ASON.

Xu, Yuegang; Yang, Wanchun; Han, Dahai; Gu, Wanyi

2005-11-01

172

Posterior mini-incision hamstring harvest.  

PubMed

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

Prodromos, Chadwick C

2010-03-01

173

Norwalk-related viral gastroenteritis due to contaminated drinking water.  

PubMed

An explosive outbreak of gastrointestinal illness clinically compatible with infection by an agent serologically related to Norwalk virus agent occurred in an elementary school in May 1978. Seroconversion by radioimmunoassay to the Norwalk antigen was noted in two of three ill persons, but no viral particles were identified in stool. Illness developed in 72% of students and teachers at the school, and 32% of household contacts of these ill persons. Of household contacts of persons exposed at school but not clinically ill, 11% developed illness. This value, however, was not statistically different from the level of illness observed concurrently in household contacts of students at an unaffected school nearby. Epidemiologic investigation implicated water as the mode of transmission. Average consumption of one or more glasses per day was strongly associated with illness (p less than 0.00000001). Among soccer team members with limited school contact, water consumption at the school was associated with a 14-fold greater risk of illness (p less than 0.000001). Drinking water was most likely contaminated by back-siphonage through a cross-connection between the school's well and septic tank. This contamination occurred approximately 24 to 36 hours before the outbreak developed. PMID:6272571

Taylor, J W; Gary, G W; Greenberg, H B

1981-10-01

174

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

175

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

176

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

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

Detailed measurement of the magnitude and orientation of thermal gradients in lined boreholes for characterizing groundwater flow in fractured rock  

NASA Astrophysics Data System (ADS)

Recent developments have led to revitalization of the use of temperature logging for characterizing flow through fractured rock. The sealing of boreholes using water-filled, flexible impermeable liners prevents vertical cross connection between fractures intersecting the hole and establishes a static water column with a temperature stratification that mimics that in the surrounding formation. Measurement of the temperature profile of the lined-hole, water column (using a high sensitivity single-point probe achieving resolution on the order of 0.001 °C) has identified fractures with active flow under ambient groundwater conditions (without cross connecting flow along the borehole). Detection of flow in fractures was further improved with the use of a heater to create thermal disequilibrium in the active line source (ALS) technique and eliminate normal depth limitations in the process. This paper presents another advancement; detailed measurement of the magnitude and direction of the thermal gradient to characterize flow through fractured rock. The temperature within the water column is measured along the length of the lined hole using a temperature vector probe (TVP): four high sensitivity sensors arranged in a tetrahedral pattern oriented using three directional magnetometers. Based on these data, the horizontal and vertical components of the thermal field, as well as the direction of temperature gradient are determined, typically at depth intervals of less than 0.01 m. This probe was assessed and refined by trials in over 30 lined boreholes; the results from two holes through a fractured dolostone aquifer in Guelph, Ontario are used as exampled. Since no other device exists for measuring flow magnitude and direction under the ambient flow condition created by lined holes, the performance of the TVP is assessed by examining the reproducibility of the temperature measurements through an ALS test, and by the consistency of the results relative to other types of larger-scale information from the study area. Temperature profiles were measured in lined holes under both ambient thermal conditions and subject to ALS heating of the entire length of the holes to demonstrate resolution and reproducibility. The hydraulic gradient in three-dimensional space, based on pressure measurements from three depth discrete, multilevel monitoring systems in nearby holes, was used to independently estimate variations in groundwater flow directions. The characteristics of the hydraulic and thermal regimes are compared to assess response to changes in flow in a fractured rock system. When used in the lined holes, the level of detail provided by this multi-sensor probe is much greater than that provided by a single-sensor probe and this detail strongly supports inferences concerning the relative magnitude and direction of the flow. The results of this study indicate that the details of the thermal gradient can be measured and provides superior results compared to a conventional one dimensional temperature profile, thereby substantially enhancing the characterization of groundwater flow in fractured rock.

Pehme, Peeter; Parker, Beth L.; Cherry, John A.; Blohm, Detlef

2014-05-01

179

Collagen fibre arrangement and functional crimping pattern of the medial collateral ligament in the rat knee.  

PubMed

Ligaments have been described as multifascicular structures with collagen fibres cross-connecting to each other or running straight and parallel also showing a waviness or crimping pattern playing as a shock absorber/recoiling system during joint motions. A particular collagen array and crimping pattern in different ligaments may reflect different biomechanical roles and properties. The aim of the study was to relate the 3D collagen arrangement in the crimping pattern of the medial collateral ligament (MCL) to its functional role. The MCL is one of the most injured ligaments during sports activities and an experimental model to understand the rate, quality and composition of ligaments healing. A deep knowledge of structure-function relationship of collagen fibres array will improve the development of rehabilitation protocols and more appropriate exercises for recovery of functional activity. The rat MCL was analysed by polarized light microscopy, confocal laser microscopy and scanning electron microscopy (SEM). Histomorphometric analysis demonstrated that MCL crimps have a smaller base length versus other tendons. SEM observations demonstrated that collagen fibres showing few crimps were composed of fibrils intertwining and crossing one another in the outer region. Confocal laser analyses excluded a helical array of collagen fibres. By contrast, in the core portion, densely packed straight collagen fibres ran parallel to the main axis of the ligament being interrupted both by planar crimps, similar to tendon crimps, and by newly described right-handed twisted crimps. It is concluded that planar crimps could oppose or respond exclusively to tensional forces parallel to the main ligament axis, whereas the right-handed twisted crimps could better resist/respond to a complex of tensional/rotational forces within the ligament thus opposing to an external rotation of tibia. PMID:20182866

Franchi, Marco; Quaranta, Marilisa; Macciocca, Maria; Leonardi, Luisa; Ottani, Vittoria; Bianchini, Paolo; Diaspro, Alberto; Ruggeri, Alessandro

2010-12-01

180

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

NASA Astrophysics Data System (ADS)

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

Zhong, Shan

181

A complete design flow for silicon photonics  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

182

Cross-Borehole Flowmeter Testing to Define Fracture-Flow Parameters  

NASA Astrophysics Data System (ADS)

Although conventional borehole-flow profiles routinely are used to estimate the distribution of hydraulic conductivity along boreholes in heterogeneous formations, these estimates apply only to the immediate vicinity of the borehole. Numerous studies in fractured-rock aquifers demonstrate that fracture-network connectivity is more important than local fracture permeability in determining the hydraulic conductivity of fracture rocks. Cross-borehole flow experiments, where one borehole is stressed by pumping or injection and flow is measured at discrete depth stations in adjacent boreholes, can be used to determine the properties of fracture-flow paths. A fracture-flow model is used to define characteristic type curves for simple classes of fracture connections. One of the main problems in carrying out such experiments is the potential for non-unique solutions, where a given flow response in an observation borehole can be attributed to two different kinds of fracture connections. This ambiguity is greatly reduced by stressing a borehole that is connected to a single permeable fracture, or by pumping from a borehole where individual fractures are isolated with straddle packers. Once a measured flow response is found to match a given type curve, the interval-integrated hydraulic conductivity (transmissivity) derived from previous single-borehole-flowmeter tests is used for an initial estimate, and the value of fracture-segment storage coefficient is adjusted until model predictions match measured flow. This form of type-curve analysis can be used to identify fractures that are connected in series or parallel and to discover cross-connections between fracture zones that are not otherwise indicated by the data. Examples of the application of the cross-borehole flow logging technique in fracture zone characterization are given for study sites in Maine, New Hampshire, and New York.

Morin, R. H.; Paillet, F. L.; Williams, J. H.

2001-12-01

183

New method for continuous transmissivity profiling in fractured rock.  

PubMed

A new method is presented to search for hydraulically transmissive features in open boreholes in bedrock. A flexible borehole liner made of a watertight, nylon fabric is filled with water to create a constant driving head to evert (reverse of invert) the liner down the hole so that the liner pushes the borehole water out into transmissive fractures or other permeable features. The descent rate is governed by the bulk transmissivity of the remaining permeable features below the liner. Initially, the liner descent rate or velocity is a measure of transmissivity (T) of the entire hole. As the everting liner passes and seals each permeable feature, changes in the liner velocity indicate the position of each feature and an estimate of T using the Thiem equation for steady radial flow. This method has been performed in boreholes with diameters ranging from 96 to 330?mm. Profiling commonly takes a few hours in holes 200- to 300-m long. After arrival of the liner at the bottom of the hole, the liner acts as a seal preventing borehole cross connection between transmissive features at different depths. Liner removal allows the hole to be used for other purposes. The T values determined using this method in a dolostone aquifer were found to be similar to the values from injection tests using conventional straddle packers. This method is not a replacement for straddle-packer hydraulic testing of specific zones where greater accuracy is desired; however, it is effective and efficient for scanning entire holes for transmissive features. PMID:23692626

Keller, Carl E; Cherry, John A; Parker, Beth L

2014-01-01

184

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

185

A review of outbreaks of waterborne disease associated with ships: evidence for risk management.  

PubMed Central

OBJECTIVE: The organization of water supply to and on ships differs considerably from that of water supply on land. Risks of contamination can arise from source water at the port or during loading, storage, or distribution on the ship. The purpose of this article is to review documented outbreaks of waterborne diseases associated with passenger, cargo, fishing, and naval ships to identify contributing factors so that similar outbreaks can be prevented in the future. METHODS: The authors reviewed 21 reported outbreaks of waterborne diseases associated with ships. For each outbreak, data on pathogens/toxins, type of ship, factors contributing to outbreaks, mortality and morbidity, and remedial action are presented. RESULTS: The findings of this review show that the majority of reported outbreaks were associated with passenger ships and that more than 6,400 people were affected. Waterborne outbreaks due to Enterotoxigenic Escherichia coli, noroviruses, Salmonella spp, Shigella sp, Cryptosporidium sp, and Giardia lamblia occurred on ships. Enterotoxigenic E. coli was the pathogen most frequently associated with outbreaks. One outbreak of chemical water poisoning also occurred on a ship. Risk factors included contaminated port water, inadequate treatment, improper loading techniques, poor design and maintenance of storage tanks, ingress of contamination during repair and maintenance, cross-connections, back siphonage, and insufficient residual disinfectant. CONCLUSIONS: Waterborne disease outbreaks on ships can be prevented. The factors contributing to outbreaks emphasize the need for hygienic handling of water along the supply chain from source to consumption. A comprehensive approach to water safety on ships is essential. This may be achieved by the adoption of Water Safety Plans that cover design, construction, operation, and routine inspection and maintenance. PMID:15219801

Rooney, Roisin M.; Bartram, Jamie K.; Cramer, Elaine H.; Mantha, Stacey; Nichols, Gordon; Suraj, Rohini; Todd, Ewen C. D.

2004-01-01

186

Optical networks security: a failure management framework  

NASA Astrophysics Data System (ADS)

Network security is becoming a very sensitive and important topic for equipment manufacturers and network operators. In transparent optical networks, security is even more complex since the optical signals are not regenerated as in opaque networks and, therefore, the faults and attacks at the physical layer are more difficult to detect and isolate without significantly affecting the overall network performance. In this paper we define Failure Management as the prevention, detection, and reaction against failures. Failures are defined as the interruptions of the normal functioning of the network and comprise faults (accidental interruptions) as well as attacks (intentional interruptions which can be performed by service disruption or eavesdropping). Our work deals with a solution to detection of failures in transparent networks. For this purpose we have extended a Fault Location algorithm developed for opaque optical networks to be used in transparent networks and be able to also locate attacks. The proposed algorithm is called Transparent Failure Location Algorithm (TFLA). The first part of the extension is based on the study of other optical network elements such as Optical Add/Drop Multiplexers (OADMs), Optical Cross-Connects (OXCs), wavelength converters, Optical Line Terminators, etc. The vulnerability of these elements depends on their architecture and/or fabrication technology and, therefore, different attacks can be considered. A classification of these components based on the masking and alarming properties is proposed. The second part of the extension is based on the monitoring equipment that may be available in transparent networks. The TFLA was applied for the case of a transparent ring of the Pan-European network.

Mas, Carmen; Tomkos, Ioannis; Tonguz, Ozan K.

2003-08-01

187

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

PubMed

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

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

2014-10-01

188

Eye Movement Abnormalities in Joubert Syndrome  

PubMed Central

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

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

2011-01-01

189

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

190

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

191

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

192

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

193

Assessing the Role of Sewers and Atmospheric Deposition as Nitrate Contamination Sources to Urban Surface Waters using Stable Nitrate Isotopes  

NASA Astrophysics Data System (ADS)

Excess nitrate (NO3-) contributes to the overall degraded quality of streams in many urban areas. These systems are often dominated by impervious surfaces and storm sewers that can route atmospherically deposited nitrogen, from both wet and dry deposition, to waterways. Moreover, in densely populated watersheds there is the potential for interaction between urban waterways and sewer systems. The affects of accumulated nitrate in riverine and estuary systems include low dissolved oxygen, loss of species diversity, increased mortality of aquatic species, and general eutrophication of the waterbody. However, the dynamics of nitrate pollution from each source and it’s affect on urban waterways is poorly constrained. The isotopes of nitrogen and oxygen in nitrate have been proven effective in helping to distinguish contamination sources to ground and surface waters. In order to improve our understanding of urban nitrate pollution sources and dynamics, we examined nitrate isotopes (?15N and ?18O) in base- and stormflow samples collected over a two-year period from a restored urban stream in Pittsburgh, Pennsylvania (USA). Nine Mile Run drains a 1,600 hectare urban watershed characterized by 38% impervious surface cover. Prior work has documented high nitrate export from the watershed (~19 kg NO3- ha-1 yr-1). Potential nitrate sources to the watershed include observed sewer overflows draining directly to the stream, as well as atmospheric deposition (~23 kg NO3- ha-1 yr-1). In this and other urban systems with high percentages of impervious surfaces, there is likely minimal input from nitrate derived from soil or fertilizer. In this presentation, we examine spatial and temporal patterns in nitrate isotopic composition collected at five locations along Nine Mile Run characterized by both sanitary and combined-sewer cross-connections. Preliminary isotopic analysis of low-flow winter streamwater samples suggest nitrate export from Nine Mile Run is primarily influenced by inputs of human waste despite high rates of atmospheric nitrate deposition. Further isotopic analysis of nitrate will examine seasonal variations in nitrate sources; compare nitrate dynamics and sources during low- versus high-flows, and the influence of interannual climatic variability on nitrate export.

Sikora, M. T.; Elliott, E. M.

2009-12-01

194

Purification and characterization of squid brain myosin.  

PubMed

Myosin was extracted from frozen squid brain and purified by a modification of the procedure of Pollard et al. (Pollard, T.D., Thomas, S.M., and Niederman, R. (1974) Anal. Biochem. 60, 258-266). Myosin was eluted from Bio-Gel A-15m column as a single peak of (K+-EDTA)-activated ATPase ((K+-EDTA)-ATPase) activity with an average partition coefficient (Kav) of 0.22. In sodium dodecyl sulfate-acrylamide gel electrophoresis, the purified myosin showed a predominant band with similar electrophoretic mobility as the heavy chain of rabbit skeletal muscle myosin, and two less intense bands near the bottom of the gel. No actin band was seen. The properties of the (K+-EDTA)-ATPase activity were: (a) the time course of the reaction was biphasic at 25 degrees but linear at 32 degrees; (b) the optimum rate of reaction was obtained between 0.3 and 0.8 M KCl; (c) the pH optimum was between 8.0 and 9.0; (d) the reaction was specific for ATP with an apparent Km of 0.19 mM. ATPase activity in 0.06 M KCl and 5 mM MgCl2 was increased about 1.5 times by a 10-fold excess of rabbit skeletal muscle F-actin and about 5 times by a 40-fold excess. The actin activation was inhibited slightly by the addition of 0.2 mM CaCl2 and completely by the addition of 10 mM CaCl2. Myosin formed arrowhead patterns with rabbit skeletal muscle F-actin as observed by electron microscopy of negatively stained samples. It also aggregated in bipolar filaments which attached to decorated actin filaments at different angles, as well as formed cross-connections and ladder-like patterns between actin filaments. These two forms of interactions between myosin and actin were abolished by treatment with MgATP. PMID:137240

See, Y P; Metuzals, J

1976-12-10

195

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

196

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

197

A Study of Magnetic Reconnection: From 2D Energy Release to 3D Spreading and Localization  

NASA Astrophysics Data System (ADS)

Magnetic reconnection is a plasma process in which stored magnetic energy is converted into thermal and kinetic energies of the surrounding plasma. Oppositely directed magnetic field lines break and cross connect due to a dissipative mecha- nism. The now bent, reconnected field lines retreat from the X-line (the location of reconnection) at the Alfven speed due to the magnetic tension in the reconnected magnetic field, therefore generating outflows. This dissertation addresses three fundamental properties of magnetic reconnection. Solar flares are explosive events in the solar corona in which magnetic reconnection mediates the rapid release (on the order of minutes) of energy stored in magnetic fields into the surrounding plasma. The Sweet-Parker (collisional) model was the first self-consistent theory to explain magnetic reconnection, but is far too slow to explain observations. The formation of secondary islands make Sweet-Parker reconnection faster, but is it fast enough to explain energy release rates? Collisionless (Hall) reconnection leads to energy release rates fast enough to explain observations. Large-scale resistive Hall-Magnetohydrodynamics simulations of the transition from Sweet-Parker to Hall reconnection are presented; the first to separate secondary islands from collisionless effects. Three main results are described. There exists a regime with secondary islands but without collisionless effects entering, and the reconnection rate is faster than Sweet-Parker, but significantly slower than Hall reconnection. This implies that secondary islands do not cause the fastest reconnection rates. The onset of Hall reconnection ejects secondary islands from the vicinity of the X-line, implying that energy is released more rapidly during Hall reconnection. Early models of magnetic reconnection have treated reconnection as two- dimensional. However, naturally occurring magnetic reconnection often begins in a localized region and spreads in the direction perpendicular to the plane of reconnection. Theoretical arguments and large-scale two fluid simulations are used to study the spreading of reconnection X-lines localized in the direction of the current as a function of the strength of the out-of-plane (guide) magnetic field. It is found that the mechanism causing the spreading is different for weak and strong guide fields. In the weak guide field limit, spreading is due to the motion of the current carriers. However, spreading for strong guide fields is bidirectional and is due to the excitation of Alfven waves along the guide field. In general, we suggest that the X-line spreads bidirectionally with a speed governed by the faster of the two mechanisms for each direction. A prediction of the strength of the guide field at which the spreading mechanism changes is formulated and verified with three-dimensional simulations. In the solar wind, magnetic reconnection exhausts measuring 600 [Gosling et al. (2007)] and 390 [Phan et al. (2006)] Earth radii in length have been observed. The authors assumed that the extended exhaust was caused by an extended X-line. If this is the case, what mechanism is responsible for these large scale structures? It has been suggested these structures are formed by a small X-line forming near the sun and spreading as the X-line convects away from the sun. Another possibility is the X-line is localized in a small region and the exhaust expands into the out-of-plane direction. Theoretical arguments and large-scale simulations are used to study localized (not spreading) magnetic reconnection, and its three-dimensional structure. Localized reconnection may also be vital to the formation of supra-arcade downflows (SADs) in the corona. Both solar wind and coronal applications are discussed.

Shepherd, Lucas S.

198

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

199

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

USGS Publications Warehouse

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

Hyer, Kenneth Edward

2007-01-01